WO2018159811A1

WO2018159811A1 - White laminated film and recording material

Info

Publication number: WO2018159811A1
Application number: PCT/JP2018/008008
Authority: WO
Inventors: 秀孝木村; 敬太川浪; 泰史川崎
Original assignee: 三菱ケミカル株式会社
Priority date: 2017-03-02
Filing date: 2018-03-02
Publication date: 2018-09-07
Also published as: CN114714731A; CN114714731B

Abstract

In order to provide a white laminated film that is to be used as a recording material, which is an information-printing medium to take the place of paper such as copy paper, and that is very economical, the present invention proposes a laminated white film characterized in that at least one surface of a polyester film with an apparent density of 0.7-1.3 g/cm³ and a thickness of 10-1000 µm has a functional layer containing an antistatic agent, and said polyester film comprises a polymer that is incompatible with polyester.

Description

Laminated white film and recording material

The present invention relates to a laminated white film. More specifically, the present invention relates to a plastic sheet suitable as a recording material that is an information printing medium that replaces paper such as copy paper.

Currently, with the high performance of copiers and printers, these devices can be used for various purposes and forms, such as printing and copying documents, printing photos and videos, and issuing forms and slips. Is used to issue As a result, the consumption of copy paper and printer paper in companies and homes is increasing.

Mass consumption of paper, including copy paper and printer paper, is not desirable from the standpoint of reducing deforestation, and recycled paper that has been collected from used paper and recycled into recycled pulp at paper mills has been used. .
Recycled paper is used paper collected from its main raw materials, but to make recycled paper from the collected used paper, a certain amount of new wood resources are also required. Even if the utilization rate increases, wood resources are still consumed, and the use of recycled paper is not a fundamental solution to protect the forest environment. Moreover, since energy is also required for the recycling process, there is a problem from the viewpoint of energy saving.
In addition, recycled paper is still inferior in quality to high-quality paper, and when copying paper made of recycled paper is used, the whiteness of the paper decreases and the color becomes gray. Tends to fall and image quality tends to deteriorate.
Furthermore, recycled paper tends to be more expensive than high-quality paper due to manufacturing costs.
Because of these various problems, the actual situation is that the use of paper as a substitute for high-quality paper has not been established.

In place of such recycled paper, paper that can be reused once it has been proposed by peeling and removing an image formed on the surface of the paper by an electrophotographic system such as a copying machine has been proposed. For example, based on paper mainly composed of cellulose fibers, a layer containing a polymer selected from polyvinyl alcohol, starch, carboxymethyl cellulose, polyvinyl acetate, and acrylic resin is provided on the surface on which the image of the base is recorded, A reusable recording material is disclosed in which a compound having a linear or branched alkyl group or alkenyl group is provided on a layer to be contained, and a layer having toner repellency is provided (see, for example, Patent Document 1). .
However, such a recording material has a structure in which the thickness of the polymer layer is reduced in order to reduce the cost of the polymer layer, and because the base requires paper, the wood environment is not completely used. It is not a solution to protect. In addition, as long as paper is used, the recorded image is impregnated into the fiber of the paper, so that the peeling and removal performance is insufficient.

Therefore, as a material that completely replaces paper, plastic synthetic paper is also being examined. For example, synthetic paper made of polypropylene is used for daily necessities. (For example, see Patent Document 2)

JP 2005-234162 A Japanese Patent Laid-Open No. 10-204196

However, the synthetic paper described in Patent Document 2 is vulnerable to heat, and when used in a copying machine or printer that fixes toner at a relatively high temperature, the synthetic paper melts in the copying machine, causing wrinkles and causing paper jams. Could occur.

The present invention has been made in view of the above circumstances, and the problem to be solved is a laminated white that can be used as a recording material that is an information printing medium that replaces paper such as copy paper, and is extremely excellent in cost. To provide a film. It is also an object of the present invention to reduce film clogging in a conveying process in a copying machine as a recording material for copying paper and printer paper.

The gist of the present invention is that a polyester film having an apparent density of 0.7 to 1.3 g / cm ³ and a thickness of 10 to 1000 μm has a functional layer containing an antistatic agent on at least one side, and The polyester film is a laminated white film characterized by containing a polymer incompatible with polyester.

The laminated white film of the present invention is used as a recording material, which is an information printing medium that replaces paper such as copy paper, because the polyester film as a base material contains a polymer incompatible with the polyester in addition to the polyester. In addition, it is a plastic film that is extremely cost effective. Furthermore, the laminated white film of the present invention can transfer a toner image suitably. That is, the toner image can be suitably transferred by an electrophotographic method or a thermal transfer method that transfers the toner image to the recording material. Further, after being used as a recording material, it is possible to easily peel off and remove characters and images from an image forming substance or the like formed on the surface.
In addition, since the polyester film has a functional layer containing an antistatic agent on at least one surface, it is possible to reduce clogging of the film in a transport process in a copying machine as a recording material for copying paper or printer paper.

Furthermore, by including a release agent in the functional layer, after using it as a recording material as described above, it is possible to easily peel off characters and images from an image-forming substance containing a thermoplastic resin formed on the surface. Since it can be removed, it can be recycled. Therefore, a film having both the characteristics of toner image transfer, that is, the characteristic of fixing the image forming substance to the film base material, and the opposite of the characteristic of peeling the image forming substance from the film base material, can do.

Hereinafter, the present invention will be described in more detail.

<< First Embodiment >>
As an example of the first embodiment for carrying out the present invention, a laminated white film 1 having a functional layer containing an antistatic agent on at least one side of a polyester film as a substrate (“the present laminated white film 1” and Will be described.

<Polyester film>
It is preferable that the polyester film used as the base material of the laminated white film 1 includes a polyester resin layer containing at least a polyester as a main component resin and a polymer incompatible with the polyester.
Here, the “main component resin” means a resin having the highest content ratio among the resin components constituting the polyester resin layer. It can be assumed that the main component resin occupies 30% by mass or more, particularly 50% by mass or more, of which 80% by mass (including 100% by mass) among the resin components constituting the polyester resin layer.

The polyester film may be a single layer composed of the above polyester resin layer, or may be a two-layer, three-layer, four-layer or more multilayer having a polyester resin layer, and is particularly limited. is not. That is, when the polyester film is a single layer, the polyester film means the polyester resin layer itself. Moreover, when the said polyester film is two or more layers, all the layers may be a polyester resin layer, and one or more layers may be resin layers other than polyester. In particular, it is preferable that all the layers are polyester resin layers.
Especially, it is preferable that the polyester film is laminated | stacked on two or more layers, and 3 layer structure (surface layer / intermediate layer / surface layer) which consists of both surface layers and an intermediate | middle layer is more preferable.
In addition, the case where a laminated structure is two layers means that it is comprised by two surface layers, and specifically, 2 of the composition from which mixing | blending of the kind of polyester which comprises each layer, the particle | grains to contain, etc. differs. The case where it forms with a layer is mentioned.

(polyester)
The polyester film as the substrate, particularly the polyester constituting the polyester resin layer, may be obtained by polycondensation of aromatic dicarboxylic acid and aliphatic glycol.
Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid. Examples of the aliphatic glycol include ethylene glycol, diethylene glycol, trimethylene glycol, tetramethylene glycol, neopentyl glycol, 1 , 4-cyclohexanedimethanol and the like.

Typical polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), polybutylene terephthalate, and the like.
Such a polyester may be a homopolymer that is not copolymerized, 20 mol% or less of the dicarboxylic acid component is a dicarboxylic acid component other than the main component, and / or 20 mol% or less of the diol component is other than the main component. It may be a copolyester that is a diol component. Moreover, those mixtures may be sufficient.

Polyester is a conventionally known method, for example, a method of directly obtaining a polyester by reaction of a dicarboxylic acid and a diol, or a reaction of a lower alkyl ester of a dicarboxylic acid and a diol with a conventionally known transesterification catalyst, and the presence of a polymerization catalyst. It can obtain by the method of performing a polymerization reaction under. As the polymerization catalyst, known catalysts such as an antimony compound, a germanium compound, a titanium compound, and an aluminum compound can be used.
The intrinsic viscosity of the polyester is preferably 0.55 to 0.75 dl / g as measured by the method described in the Examples section below, and more preferably 0.60 dl / g or more or 0.70 dl. / G or less is more preferable.

(Polyester incompatible with polyester)
By containing a polymer incompatible with polyester in the polyester film, particularly the polyester resin layer, the polyester film stretched at least in the uniaxial direction can contain innumerable fine cavities. Due to the fine cavities, the polyester film can not only scatter light and cause white opacity, but also reduce the apparent density of the polyester film. In addition, an image forming substance containing a thermoplastic resin such as toner printed on the surface of the polyester film can be easily fixed and easily peeled and removed.
By containing a polymer incompatible with polyester on the surface of the polyester film, it contains a thermoplastic resin such as toner printed on the surface of the laminated white polyester film when used as a recording material for copying paper or printer paper. The image forming substance can be easily fixed and easily removed. That is, by having a fine cavity on the surface layer of the polyester film or roughening the surface, an anchor effect for satisfactorily fixing the image forming substance can be exhibited. Further, since the surface layer contains a polymer that is incompatible with polyester, the fixing power of the image forming substance can be adjusted, so that it can be easily peeled and removed. Surprisingly, such an effect can be expressed in the same manner or even more significantly even when a functional layer described later is provided on the surface of the polyester film.
Moreover, in order to ensure sufficient concealability and weight reduction, a polymer incompatible with polyester may be included in the intermediate layer as necessary.

In addition, when a polyester film is a laminated structure, the polymer incompatible with polyester may be contained in all layers of the polyester film, or may be selectively contained in a specific layer. Specifically, the polymer incompatible with the polyester may be contained in at least one surface layer of the polyester film or may be contained in the intermediate layer.

As the polymer incompatible with the polyester, a conventionally known polymer can be used, and examples thereof include polyolefin, polystyrene, polyacryl, polycarbonate, etc. Among them, polyolefin and polystyrene are preferable, and polyolefin is more preferable. . Further, among polyolefins, polypropylene, polyethylene, poly-4-methylpentene-1, amorphous polyolefin, and the like can be mentioned. Among these, polypropylene is more preferable in view of the formation of cavities and the ease of film formation.
In addition, polyester different from the main component resin which comprises a polyester film can also be used as a polymer incompatible with polyester.

When polypropylene is used as a polymer incompatible with polyester, the content of propylene units in the polypropylene is preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more. By reducing the content of copolymer units other than propylene units and using them in the above range, the formation of fine cavities can be made sufficient.

In the polyester resin layer, the content of the polymer incompatible with the polyester is 1 to 70 parts by mass of the polymer incompatible with the polyester with respect to 100 parts by mass of the polyester. Preferably, it is more preferably 2 parts by mass or more and 50 parts by mass or less, more preferably 3 parts by mass or more or 40 parts by mass or less, and more preferably 5 parts by mass or more or 35 parts by mass or less. Particularly preferred.

When using polypropylene as a polymer incompatible with polyester, the melt flow index of polypropylene under the conditions of a temperature of 230 ° C. and a load of 2.16 kg (21.2 N) is usually 0.5 ml / 10 min or more as a lower limit. Preferably it is 1 ml / 10 minutes or more, More preferably, it is 3 ml / 10 minutes or more, More preferably, it is 5 ml / 10 minutes or more. In the case of the above range, it is possible to generate a sufficient cavity size and to easily avoid breakage during stretching.
On the other hand, the upper limit is usually 50 ml / 10 minutes or less, preferably 40 ml / 10 minutes or less, more preferably 30 ml / 10 minutes or less, and further preferably 25 ml / 10 minutes or less. In the case of the above range, it is possible to avoid clip detachment at the time of transverse stretching, and it is possible to maintain productivity.

The lower limit of the content of the “polyester incompatible polymer” in the polyester film is usually 1% by weight or more, preferably 2% by weight or more, more preferably 3% by weight or more, still more preferably 5% by weight or more, particularly preferably. Is 8% by weight or more. By using in the above range, the amount of fine cavities generated in the film becomes sufficient, the concealability of the film is improved, and the effect of reducing the apparent density, that is, the weight reduction is sufficient. In addition, the slipperiness of the film and the writing property of a pencil or the like are improved, which is advantageous for the print transportability. Furthermore, on the film surface, characters and images due to printed image forming substances and the like are easily fixed and peeled and removed, and the film can be repeatedly used as a recording material for copying paper and printer paper.
On the other hand, the upper limit of the content of the “polyester incompatible polymer” in the polyester film is usually 70% by weight or less, preferably 50% by weight or less, more preferably 40% by weight or less, more preferably 35% by weight or less, Especially preferably, it is 30 weight% or less, Most preferably, it is 25 weight% or less. By using the “polyester incompatible with the polyester” in a content within the range, the amount of voids generated is not too much, and there is a tendency that breakage during stretching is easily suppressed.
In addition, when a polyester film is a laminated structure, said content may mean the average content rate in a polyester film whole layer, and may mean content in a specific layer. Specifically, the content in at least one surface layer of the polyester film may mean the content in the intermediate layer.

Moreover, when a polyester film is a structure of 3 layers or more, an intermediate | middle layer is a surplus part which generate | occur | produces at the time of film manufacture, for example, an end part (ear part), a master roll end part (ear part), and a master roll surplus part (under winding) Part) and the like may be blended within a range not impairing the gist of the present invention. The inclusion of recycled products has the effect of reducing costs and reducing environmental impact.
The content of the recycled product in the intermediate layer is preferably 95% by weight or less, more preferably 85% by weight or less with respect to the intermediate layer from the viewpoint of film formation stability due to a decrease in intrinsic viscosity in addition to color tone regulation. More preferably, it is 70% by weight or less, particularly preferably 60% by weight or less, and most preferably 40% by weight or less. The lower limit of the content of the recycled product in the intermediate layer is not limited and may be 0% by weight. From the viewpoint of cost reduction, it is preferably 1% by weight or more, more preferably 3% by weight or more, and further preferably 5% by weight or more.

(Metal compound particles)
It is also possible for the polyester film to contain metal compound particles for the purpose of further improving concealability and whiteness. When the said polyester film is two or more layers, it is preferable to also contain a metal compound particle in the said polyester resin layer.
When the polyester film has a structure of three or more layers, the layer containing the metal compound particles may be a surface layer or an intermediate layer. In order to effectively improve the concealability and whiteness, it is preferably contained in the surface layer.

The metal compound particles tend to compensate for the white opacity due to the light scattering effect generated by the fine cavities formed by blending the above-mentioned “polyester incompatible polymer”, so that a higher hiding degree and There is a tendency to obtain whiteness.
Examples of the metal compound particles include titanium oxide, calcium carbonate, barium sulfate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, zirconium oxide, and the like. From the viewpoint of improving whiteness, titanium oxide, calcium carbonate, barium sulfate and the like are preferable, and among these, titanium oxide is particularly suitable.

The lower limit of the average particle diameter of the metal compound particles is usually 0.05 μm or more, preferably 0.10 μm or more, more preferably 0.20 μm or more, further preferably 0.25 μm or more, and the upper limit is usually 0.50 μm or less. , Preferably 0.45 μm or less, more preferably 0.40 μm or less. By using metal compound particles having an average particle size in the above range, the degree of concealment when a film is formed becomes sufficient, and there is a tendency for show-through when the entire surface is printed on both sides of the film.
The shape of the compound particles is not particularly limited, and may be any of a spherical shape, a block shape, a rod shape, a flat shape, and the like. Moreover, there is no restriction | limiting in particular about the hardness, specific gravity, a color, etc. Two or more kinds of these particles may be used in combination as required.

The lower limit of the content of the metal compound particles is preferably 1% by weight or more, more preferably 2% by weight or more, further preferably 3% by weight or more, and the upper limit is usually 30% by weight or less, preferably 20% by weight. Hereinafter, it is more preferably 15% by weight or less, further preferably 13% by weight or less, and particularly preferably 10% by weight or less. By setting the content of the metal compound particles in the above range, a sufficient degree of concealment can be imparted, which is also advantageous in terms of cost, and recording on copy paper and printer paper instead of paper made of paper. It tends to be optimal to use as a material.
In addition, when a polyester film is a laminated structure, said content may mean the average content rate in a polyester film whole layer, and may mean content in a specific layer. Specifically, the content in at least one surface layer of the polyester film may mean the content in the intermediate layer.

(Particles other than metal compound particles)
In order to improve the handleability and the slipperiness of the present laminated white film 1, the polyester film may contain particles other than the metal compound particles exemplified above.
Specific examples of the particles other than the metal compound particles exemplified above include silica particles and organic particles. Specific examples of the organic particles include acrylic resins, styrene resins, urea resins, phenol resins, epoxy resins, and benzoguanamine resins. Of these, silica particles are preferred because they are particularly effective in a small amount.

The average particle diameter of the particles (silica particles or organic particles) other than the metal compound particles exemplified above is preferably more than 0.50 μm, more preferably 1.0 μm or more, further preferably 1.5 μm or more, particularly preferably. 2.0 μm or more. By setting the average particle size of the particles other than the metal compound particles in the above range, sufficient slipperiness tends to be imparted. In addition, the upper limit of the average particle size of the particles is usually 15.0 μm or less, preferably 12.0 μm or less, more preferably 10.0 μm or less, and further preferably 8.0 μm or less. By setting the above range, the film surface does not become too rough, and it is easy to peel off and remove characters and images such as image forming substances printed on the film surface, and the film is repeatedly recorded on copying paper and printer paper. It tends to be usable as a material. Furthermore, it is not necessary to extremely increase the thickness of the surface layer from the aspect of particle dropout, and the optimum range of the thickness is wide, which is a preferable form.

The shape of the particles (silica particles or organic particles) other than the metal compound particles exemplified above is not particularly limited, and may be any shape such as a spherical shape, a block shape, a rod shape, and a flat shape. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. Two or more kinds of these particles may be used in combination as required.

Since the content of particles (silica particles or organic particles) other than the metal compound particles exemplified above depends on the average particle size, it cannot be said unconditionally. For example, for a polyester film containing silica particles or organic particles, it is usually 5% by weight or less, preferably 3% by weight or less, more preferably 2% by weight or less, still more preferably 1% by weight or less, and a preferred range. The lower limit is 0.005% by weight or more, more preferably 0.05% by weight or more, and still more preferably 0.1% by weight or more. If it is the said range, it will become possible to make the surface roughness of a film moderate, and it exists in the tendency which can achieve the target slipperiness provision. In addition to providing slipperiness, it also makes it easier to peel off and remove characters and images such as image forming substances printed on the film surface, making the film suitable as a recording material for repetitive copying paper and printer paper. Tend to be able to. Furthermore, the role of silica particles and organic particles tends to further improve the writing properties of pencils, mechanical pencils and ballpoint pens.
In addition, when a polyester film is a laminated structure, said content may mean the average content rate in a polyester film whole layer, and may mean content in a specific layer. Specifically, the content in at least one surface layer of the polyester film may mean the content in the intermediate layer.

(Other ingredients)
Since the polyester film as the base material of the present laminated white film 1 contains an incompatible polymer, the extruded sheet is stretched at least in a uniaxial direction, so that a fine independent space (cavity) is formed inside the film. ) Can be obtained. Therefore, in order to further refine the cavity or increase the concealability and whiteness, for example, a surfactant, inert particles, fluorescent whitening agent, and the like may be blended.

In addition to the above-mentioned particles and polyester incompatible polymers, conventionally known antioxidants, thermal stabilizers, lubricants, antistatic agents, dyes, pigments, etc. may be added to the polyester film as necessary. it can. Further, depending on the use, an ultraviolet absorber, particularly a benzoxazinone-based ultraviolet absorber may be contained.

(In the case of laminated structure)
When the polyester film as the substrate of the present laminated white film 1 has a laminated structure of two or more layers, if it is two layers, any one of them, and if it is three or more layers, the surface layer thereof is the polyester resin layer. Is preferred.

For example, in the case of a laminated structure of three or more layers, if the surface layer contains the above polyester and a polymer that is incompatible with the polyester, a fine cavity can be provided by stretching. Whitening can be achieved. Further, since the surface roughness can be adjusted, the writing property can be improved, the image by the image forming substance or the like can be easily fixed, and it can be peeled off after use.
If the surface layer further contains metal compound particles, the concealability and whiteness can be further increased, and the slipperiness can be improved by containing particles other than the metal compound particles.

On the other hand, as long as the intermediate layer other than the surface layer contains the polyester, the polymer, metal compound particles, and particles other than the metal compound particles that are incompatible with the polyester may be contained as necessary. It is preferable from the viewpoint of cost reduction and environmental load reduction that the content of the metal compound particles and particles other than the metal compound particles is made as small as possible, and the recycled polyester is used.

(Thickness)
The thickness of the polyester film is preferably 10 μm to 1000 μm, more preferably 20 μm or more and 500 μm or less, more preferably 30 μm or more and 400 μm or less, and particularly preferably 38 μm or more or 350 μm or less.
By using it in the above range, the hardness (stiffness) and handleability of the film can be made sufficient, and clogging of the film in the transporting process in the copying machine can be reduced.

When the polyester film has a laminated structure of three or more layers as described above, the thickness of each surface layer is preferably 1 μm to 50 μm, especially 2 μm or more and 40 μm or less, particularly 3 μm or more or 30 μm or less, and especially 4 μm. More preferably, it is 25 μm or less. By using it in the above-mentioned range, it becomes possible to sufficiently exhibit the performance of the above-described metal compound particles and particles other than the metal compound particles, and the production cost can be suppressed at a low cost.

(Apparent density)
The lower limit of the apparent density of the polyester film is 0.7 g / cm ³ or more, preferably 0.75 g / cm ³ or more, more preferably 0.8 g / cm ³ or more. By setting the lower limit of the apparent density to the above range, the film strength can be maintained, and the film is clogged during the transport process in the copying machine when used as a recording material instead of copying paper or printer paper as an information printing medium. Can be reduced, and optimal printing can be performed.
On the other hand, the upper limit of the apparent density is 1.3 g / cm ³ or less, preferably 1.2 g / cm ³ or less, more preferably 1.1 g / cm ³ or less. By setting the upper limit of the apparent density within the above range, the work burden when carrying a large amount of printed materials is reduced, and furthermore, the environmental load can be reduced and the cost can be reduced by reducing CO ₂ generated during the film (sheet) transportation process. It becomes possible.
The apparent density of the polyester film can be adjusted to form fine independent cavities inside the film by blending an incompatible polymer with a specific gravity lighter than that of polyester, the main component resin, and stretching it at least in the uniaxial direction. it can. However, it is not limited to these methods.

(Physical properties of polyester film)
The arithmetic average roughness (Ra) of the surface of the polyester film is based on JIS B0601 (2001). The arithmetic average roughness (Ra) varies depending on the application to be used, but the upper limit is usually 950 nm or less, preferably 850 nm or less, more preferably 800 nm or less. By using a polyester film with an arithmetic average roughness (Ra) in the above range, it is easy to fix characters and images such as image-forming substances containing thermoplastic resin formed on the film surface, and to easily remove and remove. Therefore, the film tends to be repeatedly used as a recording material for copying paper and printer paper.
On the other hand, the lower limit of the arithmetic average roughness (Ra) is usually 100 nm or more, preferably 200 nm or more, more preferably 300 nm or more, and further preferably 350 nm or more. By setting the arithmetic average roughness (Ra) within the above range, it is possible to achieve sufficient concealability and transportability, and to make the film optimal for use as a recording material for copy paper and printer paper. Tend to be possible. Furthermore, it tends to have sufficient writing property.

The b value (reflection method), which is an index representing the yellowness of the polyester film, is usually 0 or less, preferably −0.20 or less, more preferably −0.40 or less, even more preferably −0.50 or less, particularly preferably. Is −0.60 or less, and the lower limit is not particularly limited, but is preferably −5.0 or more. By using in the said range, yellowness can be suppressed and whiteness can be made favorable. Further, when used as a recording material for color printing, the obtained image quality tends to be excellent.

The polyester film has a heat shrinkage in the film longitudinal direction (MD) and film width direction (TD) at 150 ° C. for 30 minutes of usually 2.8% or less, preferably 2.3% or less, more preferably as an absolute value. 2.0% or less.
By setting the heat shrinkage rate of the polyester film in the above range, it is possible to prevent the film from being damaged in the dimensional stability due to heat when printing on a recording material by a method such as an electrophotographic method or a thermal transfer method. it can. In particular, even in the edge portion of the film (sheet), that is, the portion where wrinkles are likely to occur, the generation of wrinkles in the polyester film can be suppressed, and distortion and unevenness occur in characters and images, resulting in deterioration of image quality. It tends to be possible to suppress the phenomenon. In addition, once wrinkles are generated, they cannot be erased and cannot be repeatedly used as a recording material for copying paper or printer paper.

The concealability (OD) of the polyester film is usually 0.30 or more, preferably 0.35 or more, more preferably 0.40 or more, and further preferably 0.45 or more, when a single film is measured with a Macbeth densitometer. It is. By using within the above range, the show-through when the entire surface is printed on both sides of the film is reduced, and it tends to be possible to obtain characters and images of good quality. On the other hand, the upper limit of the concealing property (OD) is not particularly limited, but is preferably 1 or less, more preferably 0.9 or less, considering the balance of other physical properties.

The whiteness of the polyester film is determined by measuring the Hunter whiteness (Wb) when the film is a single sheet with a colorimeter. The lower limit is usually 80.0% or more, preferably 81.0% or more, more preferably 82. It is 0% or more, more preferably 83.0% or more, and particularly preferably 83.5% or more. By setting the whiteness to the above range, high-definition characters and images can be used as recording materials for copy paper and printer paper, which are information printing media that replace paper, especially when color printing is performed. Therefore, it tends to be preferable in terms of quality. Moreover, although depending on the use to be used, in order to give a high-class feeling, a higher one is preferable, and the upper limit is not particularly limited. On the other hand, when used in applications where gloss is a concern, the upper limit of the preferred range is 95.0% or less.

<Functional layer>
Next, the functional layer which comprises this laminated white film 1 is demonstrated.
This functional layer can serve as a recording layer on which the image forming substance adheres directly to the layer surface, for example. The recording layer in the present invention is a layer that not only fixes the attached image forming substance but also has a role of removing the image forming substance together with the resin layer when a resin layer described later is provided.

The functional layer in the laminated white film 1 preferably has antistatic performance and release performance.
The present laminated white film 1 has a reduced apparent density, can be whitened without cost, and can easily remove and remove characters and images such as image forming substances containing a printed thermoplastic resin. In order to realize the above, it is preferable to provide a polyester resin layer containing polyester and a polymer incompatible with polyester, and it is more preferable that the polyester resin layer has a surface layer. However, when the functional layer is provided, it has been found that it may be difficult to express the ability to easily peel off and remove characters and images such as image forming substances on the surface. It is preferable to provide performance.

(Antistatic agent)
When used as a recording material for copy paper and printer paper, this laminated white film 1 is used for the purpose of preventing double feeding in the paper transport of copiers and multifunction machines, and preventing sticking between papers when handling paper. It is preferable to have a functional layer containing an agent on at least one side. In addition, by containing an antistatic agent in the functional layer, there is no clogging of the film in the multi-function machine, there is no occurrence of double feeding of the printed film, and each sheet can be conveyed independently, and dust adheres to it. Therefore, it is possible to obtain a film having a high quality and a film printed matter having a good image quality.

The antistatic agent contained in the functional layer is not particularly limited, and a conventionally known antistatic agent can be used. For example, it is preferable to be a polymer type antistatic agent because of its good heat resistance and moist heat resistance.
Examples of the polymer type antistatic agent include a compound having an ammonium group, a polyether compound, a compound having a sulfonic acid group, a betaine compound, and a conductive polymer.
In view of antistatic performance, a compound having an ammonium group or a compound having a sulfonic acid group is preferable. In consideration of compatibility with other materials forming a functional layer such as a release agent, a compound having an ammonium group is more preferable. preferable. Conductive polymers are preferred because they have the best antistatic properties. However, there is a possibility that the use is limited in applications where the material is expensive and coloring is extremely disliked.

Examples of the compound having an ammonium group include aliphatic amines, alicyclic amines, and ammonium amines of aromatic amines.
The compound having an ammonium group is preferably a compound having a polymer type ammonium group, and the ammonium group has a structure incorporated in the main chain or side chain of the polymer, not as a counter ion. It is preferable. For example, a polymer obtained by polymerizing a monomer containing an addition-polymerizable ammonium group or a precursor of an ammonium group such as an amine is preferably used. As the polymer, a monomer containing an addition polymerizable ammonium group or a precursor of an ammonium group such as an amine may be polymerized alone, or it may be a copolymer of a monomer containing these and another monomer. May be.

Among the compounds having an ammonium group, compounds having a pyrrolidinium ring are also preferred in that they are excellent in antistatic properties and heat stability.

The two substituents bonded to the nitrogen atom of the compound having a pyrrolidinium ring are each independently an alkyl group, a phenyl group, and the like. Even if these alkyl groups and phenyl groups are substituted with the groups shown below, Good.
Substitutable groups are, for example, hydroxyl group, amide group, ester group, alkoxy group, phenoxy group, naphthoxy group, thioalkoxy, thiophenoxy group, cycloalkyl group, trialkylammonium alkyl group, cyano group, and halogen. Further, the two substituents bonded to the nitrogen atom may be chemically bonded. For example, — (CH ₂ ) m — (m = 2 to 5), —CH (CH ₃ ) CH (CH ₃ ) —, —CH═CH—CH═CH—, —CH═CH—CH═N—, —CH═CH—N═CH—, —CH ₂ OCH ₂ —, — (CH ₂ ) ₂ O (CH ₂ ) ₂ — and the like.

A polymer having a pyrrolidinium ring can be obtained by cyclopolymerizing a diallylamine derivative using a radical polymerization catalyst. The polymerization is carried out by using a polymerization initiator such as hydrogen peroxide, benzoyl peroxide, tertiary butyl peroxide in a polar solvent such as water or methanol, ethanol, isopropanol, formamide, dimethylformamide, dioxane, acetonitrile as a solvent. Although it can implement by a method, it is not limited to these. In the present invention, a compound having a polymerizable carbon-carbon unsaturated bond with a diallylamine derivative may be used as a copolymerization component.

In addition, as the compound having an ammonium group, the antistatic agent is preferably a polymer having a structure represented by the following formula (1) from the viewpoint of excellent antistatic properties and wet heat stability. A single polymer or copolymer having the structure of the following formula (1) may be copolymerized, and further a plurality of other components may be copolymerized.

For example, in the above formula, the substituent R ¹ is a hydrogen atom or a hydrocarbon group such as an alkyl group having 1 to 20 carbon atoms or a phenyl group, R ² is —O—, —NH— or —S—, and R ³ is An alkylene group having 1 to 20 carbon atoms or another structure capable of forming the structure of Formula 1, R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a phenyl group. Or a hydrocarbon group provided with a functional group such as a hydroxyalkyl group, and X − is various counter ions.

Among the above, from the viewpoint of excellent antistatic properties and wet heat resistance, in the formula (1), the substituent R ¹ is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ³ is preferably an alkyl group having 1 to 6 carbon atoms, and R ⁴ , R ⁵ and R ⁶ are preferably each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably , R ⁴ , R ⁵ , or R ⁶ is a hydrogen atom, and the other substituent is an alkyl group having 1 to 4 carbon atoms.

Examples of the anion that becomes a counter ion (counter ion) of the ammonium group of the compound having an ammonium group described above include ions such as halogen ions, sulfonates, sulfates, phosphates, nitrates, and carboxylates.

In addition, the number average molecular weight of the compound having an ammonium group is usually 1,000 to 500,000, preferably 2,000 to 350,000, more preferably 5,000 to 200,000. When the molecular weight is less than 1000, the strength of the functional layer may be weakened or the heat resistance stability may be poor. On the other hand, when the molecular weight exceeds 500,000, the viscosity of the coating solution increases, and the handleability and applicability may deteriorate.

Examples of polyether compounds include polyethylene oxide, polyether ester amide, acrylic resin having polyethylene glycol in the side chain, and the like.

The compound having a sulfonic acid group is a compound containing sulfonic acid or a sulfonate in the molecule. For example, a compound containing a large amount of sulfonic acid or a sulfonate such as polystyrene sulfonic acid is preferably used. .

Examples of the conductive polymer include polythiophene-based, polyaniline-based, polypyrrole-based, and polyacetylene-based polymers. Among them, for example, polythiophene-based polymers that use poly (3,4-ethylenedioxythiophene) in combination with polystyrene sulfonic acid. Preferably used. The conductive polymer is preferable to the other antistatic agents described above in that the resistance value is low. However, on the other hand, it is necessary to devise measures such as reducing the amount used in applications where coloring and cost are a concern.

The lower limit of the content of the antistatic agent in the functional layer is usually 1% by weight or more, preferably 3% by weight or more, more preferably 5% by weight or more, further preferably 10% by weight or more, and particularly preferably 20% by weight or more. is there. The upper limit is usually 80% by weight or less, preferably 70% by weight or less, more preferably 60% by weight or less, still more preferably 55% by weight or less, and particularly preferably 50% by weight or less. By using an antistatic agent in the above range, sufficient antistatic properties can be obtained, and it is effective for preventing sticking between films and preventing dust from adhering to printing transportability and image quality. It tends to be excellent.

(Release agent)
It is preferable to provide the functional layer with a release performance so that an image forming substance containing a thermoplastic resin formed on the film surface can be suitably peeled off after printing.
The functional layer having mold release performance may be the same as or different from the functional layer containing the antistatic agent. In particular, it is preferable that the functional layer containing the antistatic agent has a releasing property for the reason described later. In addition, when the functional layer which has mold release performance and the functional layer containing an antistatic agent are different layers, it is preferable to make the functional layer which has mold release performance into an outer layer.
It has been found that the function of separating and removing image forming substances and the like can be performed more appropriately by imparting release properties to the functional layer. That is, the present inventors have found a technique for realizing the characteristics of the fixing property and the releasability that are mutually contradictory with a single functional layer. This technology can be said to be a highly effective technology considering that a functional layer having general fixing performance cannot achieve peeling performance, while a functional layer having general peeling performance cannot realize fixing performance. . Moreover, even if a functional layer having fixing performance and a functional layer having peeling performance are laminated, it is difficult to express any performance, and the performance of the functional layer corresponding to the outermost layer is mainly reflected.
The functional layer preferably contains a release agent in order to impart release performance to the image forming substance or the like.

The release agent is not particularly limited, and a conventionally known release agent can be used. Examples thereof include a long-chain alkyl group-containing compound, a fluorine compound, a silicone compound, and wax. Among these, a long-chain alkyl compound and a fluorine compound are preferable, and a long-chain alkyl compound is more preferable from the viewpoint of low contamination and excellent peeling and removal of the image forming substance. In addition, a silicone compound is preferable when it is particularly important to remove and remove the image forming substance. In addition, wax is effective when it is desired to emphasize the printability of the image forming material on the surface. These release agents may be used alone or in combination.

Further, when the functional layer is provided by coating, a long-chain alkyl group-containing compound is preferable among the above releasing agents from the viewpoint of wettability to the polyester film.

The long-chain alkyl group-containing compound is a compound having a linear or branched alkyl group having usually 6 or more, preferably 8 or more, and more preferably 12 or more carbon atoms.
Examples of the alkyl group include hexyl group, octyl group, decyl group, lauryl group, octadecyl group, and behenyl group.
Examples of the compound having an alkyl group include various long-chain alkyl group-containing polymer compounds, long-chain alkyl group-containing amine compounds, long-chain alkyl group-containing ether compounds, and long-chain alkyl group-containing quaternary ammonium salts. . In view of heat resistance and contamination, a polymer compound is preferable. Further, from the viewpoint of effectively obtaining releasability, a polymer compound having a long-chain alkyl group in the side chain is more preferable.

A polymer compound having a long-chain alkyl group in the side chain can be obtained by reacting a polymer having a reactive group with a compound having an alkyl group capable of reacting with the reactive group. Examples of the reactive group include a hydroxyl group, an amino group, a carboxyl group, and an acid anhydride. Examples of the compound having such a reactive group include polyvinyl alcohol, polyethyleneimine, polyethyleneamine, a reactive group-containing polyester resin, and a reactive group-containing poly (meth) acrylic resin. Among these, polyvinyl alcohol is preferable in view of releasability and ease of handling.

Examples of the compound having an alkyl group capable of reacting with the reactive group include, for example, long-chain alkyl group-containing isocyanates such as hexyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate, and behenyl isocyanate; hexyl chloride, octyl chloride Long chain alkyl group-containing acid chlorides such as decyl chloride, lauryl chloride, octadecyl chloride, and behenyl chloride; long chain alkyl group-containing amines; long chain alkyl group-containing alcohols. Among these, long chain alkyl group-containing isocyanates are preferable, and octadecyl isocyanate is particularly preferable in consideration of releasability and ease of handling.

In addition, a polymer compound having a long-chain alkyl group in the side chain can also be obtained by copolymerization of a long-chain alkyl (meth) acrylate polymer or a long-chain alkyl (meth) acrylate and another vinyl group-containing monomer. . Examples of the long chain alkyl (meth) acrylate include hexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, octadecyl (meth) acrylate, and behenyl (meth) acrylate. It is done.

A fluorine compound is a compound containing a fluorine atom in the compound. In order to reduce contamination, a polymer (polymer) containing a fluorine atom is preferable. Organic fluorine compounds are preferably used from the viewpoint of coating appearance by in-line coating. For example, fluoroalkyl group-containing compounds such as perfluoroalkyl group-containing compounds, polymers of olefin compounds containing fluorine atoms, and aromatics such as fluorobenzene. Group fluorine compounds and the like. From the viewpoint of releasability, a fluoroalkyl group-containing compound is preferable, and among them, a perfluoroalkyl group-containing compound is preferable. Furthermore, the compound containing the long-chain alkyl compound which is mentioned later can also be used for a fluorine compound.

Examples of the perfluoroalkyl group-containing compound include perfluoroalkyl (meth) acrylate, perfluoroalkylmethyl (meth) acrylate, 2-perfluoroalkylethyl (meth) acrylate, 3-perfluoroalkylpropyl (meth) acrylate, Perfluoroalkyl group-containing (meth) acrylates such as 3-perfluoroalkyl-1-methylpropyl (meth) acrylate and 3-perfluoroalkyl-2-propenyl (meth) acrylate, and polymers thereof; perfluoroalkylmethyl vinyl ether, 2-perfluoroalkyl ethyl vinyl ether, 3-perfluoropropyl vinyl ether, 3-perfluoroalkyl-1-methylpropyl vinyl ether, 3-perfluoroalkyl-2-propenyl Perfluoroalkyl group-containing vinyl ether and polymers thereof such as vinyl ether and the like. In view of heat resistance and contamination, a polymer is preferable. The polymer may be a single compound or a polymer of multiple compounds.

Further, from the viewpoint of releasability, the perfluoroalkyl group preferably has 3 to 11 carbon atoms. Further, it may be a polymer with a compound containing a long-chain alkyl compound as described later. Moreover, it is also preferable that it is a polymer with vinyl chloride from a viewpoint of adhesiveness with a base material.

Examples of the silicone compound include alkyl silicones such as dimethyl silicone and diethyl silicone, phenyl silicone having a phenyl group, and methyl phenyl silicone. Silicone having various functional groups can be used, and examples thereof include ether groups, hydroxyl groups, amino groups, epoxy groups, carboxylic acid groups, halogen groups such as fluorine, and perfluoroalkyl groups. As other functional groups, silicones having vinyl groups and hydrogen silicones in which hydrogen atoms are directly bonded to silicon atoms are also common, and both are used in combination to form silicones (addition reaction between vinyl groups and hydrogen silane). It can also be used.

It is also possible to use modified silicones such as acrylic graft silicone, silicone graft acrylic, amino-modified silicone, perfluoroalkyl-modified silicone as the silicone compound. In view of heat resistance and contamination, it is preferable to use a curable silicone resin. As the type of curable type, any of the curing reaction types such as a condensation type, an addition type, and an active energy ray curable type can be used.

The wax is a wax selected from natural waxes, synthetic waxes, and blended waxes.

Natural waxes are plant waxes, animal waxes, mineral waxes and petroleum waxes. Examples of plant waxes include candelilla wax, carnauba wax, rice wax, wood wax, jojoba oil and the like. Animal waxes include beeswax, lanolin, whale wax and the like. Examples of the mineral wax include montan wax, ozokerite, and ceresin. Examples of petroleum wax include paraffin wax, microcrystalline wax, and petrolatum.

Synthetic waxes include synthetic hydrocarbons, modified waxes, hydrogenated waxes, higher fatty acid esters, fatty acid amides, amines, imides, ester waxes, ketones, and the like.
Specific examples of synthetic hydrocarbons include Fischer-Tropsch wax (also known as sazol wax) and polyethylene wax, as well as low molecular weight polymers (specifically, polymers having a number average molecular weight of 500 to 20000). And the following polymers, namely, polypropylene, ethylene / acrylic acid copolymer, polyethylene glycol, polypropylene glycol, polyethylene glycol and polypropylene glycol block or graft conjugate, and the like.

Specific examples of the modified wax include montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives. The derivative herein is a compound obtained by any of purification, oxidation, esterification, saponification treatment, or a combination thereof.
Specific examples of hydrogenated wax include hardened castor oil and hardened castor oil derivatives.

Among them, from the viewpoint of stabilization of properties such as blocking, a synthetic wax is preferable as the release agent in the functional layer, among which polyethylene wax is more preferable, and oxidized polyethylene wax is more preferable. The number average molecular weight of the synthetic wax is usually 500 to 30000, preferably 1000 to 15000, and more preferably 2000 to 8000, from the viewpoints of stability of properties such as blocking and handling properties.

The lower limit of the content of the release agent in the functional layer is usually 0% by weight or more, preferably 3% by weight or more, more preferably 5% by weight or more, still more preferably 8% by weight or more, and particularly preferably 10% by weight or more. is there. The upper limit is usually 80% by weight or less, preferably 70% by weight or less, more preferably 60% by weight or less, still more preferably 50% by weight or less, and particularly preferably 40% by weight or less. By using the release agent in the above range, the releasability is improved and the image forming substance can be easily peeled and removed while securing the fixing property with the image forming substance or the like.

(polymer)
In order to improve the fixability of the functional layer with an image-forming substance, etc., to facilitate the formation of the functional layer, or to improve the wettability to the base film when the functional layer is provided by coating, the functional layer includes a polymer. It is preferable to contain (an antistatic agent, a release agent, or a polymer other than the crosslinking agent described later).

Conventionally known polymers can be used as the polymer used for the functional layer. Specific examples of the polymer include acrylic resin, urethane resin, polyester resin, polyvinyl (polyvinyl alcohol, vinyl chloride vinyl acetate copolymer, etc.), polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starches and the like. . Among these, acrylic resin, urethane resin, polyester resin, and polyvinyl alcohol are preferable from the viewpoint of improving appearance, adhesion to the film of the base material, antistatic performance and stabilization of mold release performance, acrylic resin, urethane resin, Polyester resin is more preferable, and acrylic resin and urethane resin are still more preferable. In addition, acrylic resin and polyvinyl alcohol are preferable from the viewpoint of stabilization of antistatic performance and release performance, or stability in the state of a coating solution when a functional layer is formed by coating. In view of overall performance, an acrylic resin or a urethane resin is preferable, and an acrylic resin is particularly preferable.

The acrylic resin as the polymer to be contained in the functional layer is a polymer composed of polymerizable monomers including acrylic and methacrylic monomers. These may be either homopolymers or copolymers, and copolymers with polymerizable monomers other than acrylic and methacrylic monomers. Moreover, the copolymer of these polymers and other polymers (for example, polyester, polyurethane, etc.) is also included. For example, a block copolymer or a graft copolymer. Alternatively, a polymer (possibly a mixture of polymers) obtained by polymerizing a polymerizable monomer in a polyester solution or a polyester dispersion is also included. Similarly, a polymer obtained by polymerizing a polymerizable monomer in a polyurethane solution or a polyurethane dispersion (sometimes a mixture of polymers) is also included. Similarly, a polymer (in some cases, a polymer mixture) obtained by polymerizing a polymerizable monomer in another polymer solution or dispersion is also included. Moreover, in order to improve adhesiveness more, it is also possible to contain a hydroxyl group and an amino group.

The polymerizable monomer is not particularly limited, and examples thereof include various carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, citraconic acid, and salts thereof; Various hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutylhydroxyfumarate, monobutylhydroxyitaconate; methyl Various (meth) acrylates such as (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate; (meth) acrylamide, diacetone acrylamide, Various nitrogen-containing compounds such as methylolacrylamide or (meth) acrylonitrile; various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, vinyltoluene; various vinyl esters such as vinyl propionate; -Various silicon-containing polymerizable monomers such as methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, etc .; phosphorus-containing vinyl monomers; various vinyl halides such as vinyl chloride and biridene chloride; And various conjugated dienes.

The urethane resin as the polymer to be contained in the functional layer is a polymer compound having a urethane bond in the molecule, and is usually prepared by a reaction between a polyol and an isocyanate. Examples of the polyol include polyester polyols, polycarbonate polyols, polyether polyols, polyolefin polyols, and acrylic polyols. These compounds may be used alone or in combination.

Examples of the polyester polyols include polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) Acid anhydrides and polyhydric alcohols (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butane Diol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4- Pentanediol, 2-methyl-2-pro 1,3-propanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2, 5-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3- Propanediol, cyclohexanediol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyl dialkanolamine, lactone diol, etc.), those having derivative units of lactone compounds such as polycaprolactone, etc. Can be mentioned.

The above polycarbonate polyols are obtained from a polyhydric alcohol and a carbonate compound by a dealcoholization reaction. Polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentane Diol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decane Examples thereof include diol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 3,3-dimethylol heptane. Examples of the carbonate compound include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and ethylene carbonate. Examples of the polycarbonate-based polyols obtained from these reactions include poly (1,6-hexylene) carbonate, poly (3- And methyl-1,5-pentylene) carbonate.

Examples of the polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol and the like.

In consideration of compatibility with other components of the functional layer, stabilization of antistatic performance and release performance, polyester polyols and polycarbonate polyols are more preferable among the above polyols.

Examples of the polyisocyanate compound used for obtaining the urethane resin include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate, α, α, α ′, Aliphatic diisocyanates having an aromatic ring such as α'-tetramethylxylylene diisocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate and other aliphatic diisocyanates, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate , Dicyclohexylme Down diisocyanate, alicyclic diisocyanates such as isopropylidene dicyclohexyl diisocyanates. These may be used alone or in combination.

A chain extender may be used when synthesizing the urethane resin, and the chain extender is not particularly limited as long as it has two or more active groups that react with an isocyanate group. Alternatively, a chain extender having two amino groups can be mainly used.

Examples of the chain extender having two hydroxyl groups include aliphatic glycols such as ethylene glycol, propylene glycol and butanediol, aromatic glycols such as xylylene glycol and bishydroxyethoxybenzene, neopentyl glycol hydroxypivalate, and the like. And glycols such as ester glycols. Examples of the chain extender having two amino groups include aromatic diamines such as tolylenediamine, xylylenediamine, diphenylmethanediamine, ethylenediamine, propylenediamine, hexanediamine, 2,2-dimethyl-1,3- Propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10- Aliphatic diamines such as decane diamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isopropylidine cyclohexyl-4,4′-diamine, 1,4-diaminocyclohexane, 1 , 3-Bisaminomethylcyclohexane Alicyclic diamines, and the like of.

The urethane resin may use a solvent as a medium. Preferably, water is used as a medium.
In order to disperse or dissolve the urethane resin in water, there are a forced emulsification type using an emulsifier, a self-emulsification type in which a hydrophilic group is introduced into the urethane resin, and a water-soluble type. In particular, the self-emulsification type in which an ionic group is introduced into the structure of the urethane resin to form an ionomer is preferable because of excellent storage stability of the liquid and water resistance and transparency of the obtained functional layer.

At this time, examples of the ionic group to be introduced include various groups such as a carboxyl group, sulfonic acid, phosphoric acid, phosphonic acid, and quaternary ammonium salt. As a method for introducing a carboxyl group into a urethane resin, various methods can be taken in each stage of the polymerization reaction. For example, there are a method of using a carboxyl group-containing resin as a copolymer component during prepolymer synthesis, and a method of using a component having a carboxyl group as one component such as polyol, polyisocyanate, and chain extender. In particular, a method in which a desired amount of carboxyl groups is introduced using a carboxyl group-containing diol depending on the amount of this component charged is preferred.

For example, dimethylolpropionic acid, dimethylolbutanoic acid, bis- (2-hydroxyethyl) propionic acid, bis- (2-hydroxyethyl) butanoic acid, and the like are copolymerized with a diol used for polymerization of a urethane resin. Can do. The carboxyl group is preferably in the form of a salt neutralized with ammonia, amine, alkali metal, inorganic alkali or the like. Particularly preferred are ammonia, trimethylamine and triethylamine. In such a urethane resin, the carboxyl group from which the neutralizing agent has been removed in the drying step after coating can be used as a crosslinking reaction point by another crosslinking agent. Thereby, it is possible to further improve the durability, solvent resistance, water resistance, blocking resistance, and the like of the functional layer obtained in addition to excellent stability in the liquid state before coating.

The polyester resin as the polymer to be contained in the functional layer includes, for example, those composed of the following polyvalent carboxylic acid and polyvalent hydroxy compound as main constituent components. That is, as the polyvalent carboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4′-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 2,6 -Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutar Acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid, trimellitic acid monopotassium salt and ester-forming derivatives thereof can be used. As the polyvalent hydroxy compound, ethylene Recall, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol , Neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, Polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, potassium dimethylolpropionate, and the like can be used. One or more compounds may be appropriately selected from these compounds, and a polyester resin may be synthesized by a conventional polycondensation reaction.

The polyvinyl alcohol as the polymer to be contained in the functional layer has a polyvinyl alcohol moiety. For example, polyvinyl alcohol including modified compounds partially acetalized or butyralized with respect to polyvinyl alcohol is known. Alcohol can be used. The degree of polymerization of polyvinyl alcohol is not particularly limited, but is usually 100 or more, preferably 300 to 40,000. When the degree of polymerization is less than 100, the water resistance of the functional layer may decrease. The degree of saponification of polyvinyl alcohol is not particularly limited, but is preferably 50 mol% or more, more preferably 70 to 99 mol%, still more preferably 80 to 98 mol%, and particularly preferably 86 to 97 mol%. It is a polyvinyl acetate saponified product.

The lower limit of the polymer content in the functional layer is usually 0% by weight or more, preferably 3% by weight or more, more preferably 5% by weight or more, still more preferably 10% by weight or more, and particularly preferably 15% by weight or more. The upper limit is usually 80% by weight or less, preferably 70% by weight or less, more preferably 60% by weight or less, still more preferably 55% by weight or less, and particularly preferably 50% by weight or less. By using the polymer in the above range, it is easy to form an image-forming substance, improved adhesion to the base film, and excellent wettability to the base film when a functional layer is provided by coating. Appearance tends to be achieved.

(Crosslinking agent)
It is preferable to further contain a crosslinking agent in order to increase the strength of the functional layer and to improve fixability with an image forming substance or the like. At this time, the functional layer after crosslinking contains a crosslinked structure derived from the crosslinking agent. That is, the functional layer containing a crosslinking agent means a functional layer formed by curing a coating solution containing a crosslinking agent.
Moreover, it exists in the tendency which can give the property of the wettability improvement to a base film by containing a crosslinking agent in a functional layer. According to the study by the present inventors, when a polyester film as a base material contains a polymer incompatible with polyester, particularly polyolefin, the wettability is poor when a functional layer is provided by coating, and the coating solution It turns out that there is a case where it is repelled. However, surprisingly, it has been found that wettability is greatly improved by including a cross-linking agent in the functional layer.

As the crosslinking agent, conventionally known materials can be used, and examples thereof include oxazoline compounds, isocyanate compounds, epoxy compounds, melamine compounds, carbodiimide compounds, silane coupling compounds, hydrazide compounds, and aziridine compounds. Among these, oxazoline compounds, isocyanate compounds, epoxy compounds, melamine compounds, carbodiimide compounds, and silane coupling compounds are preferable. In order to further strengthen the strength of the functional layer, a melamine compound or an oxazoline compound is preferable, and in order to improve adhesion to the base film, an oxazoline compound, an isocyanate compound, an epoxy compound, or a carbodiimide compound is preferable. In particular, oxazoline compounds and isocyanate compounds are preferred.

As the cross-linking agent, the above-mentioned materials can be used. Among them, oxazoline compounds, isocyanate compounds, epoxy compounds, and silane coupling compounds are preferable for improving wettability, and among them, oxazoline compounds and isocyanate compounds are more preferable. . That is, when considered comprehensively, the most preferable material for the crosslinking agent is an oxazoline compound or an isocyanate compound. These crosslinking agents may be used alone or in combination of two or more.

The oxazoline compound used as the crosslinking agent is particularly preferably a polymer containing an oxazoline group, and can be prepared by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with another monomer. Addition-polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, Examples thereof include 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like, and one or a mixture of two or more thereof can be used.

Of these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not limited as long as it is a monomer copolymerizable with an addition polymerizable oxazoline group-containing monomer. For example, (meth) acrylic acid esters such as alkyl (meth) acrylate; acrylic acid, methacrylic acid, itaconic acid, malein Unsaturated carboxylic acids such as acid, fumaric acid, crotonic acid, styrenesulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile, methacrylonitrile; Unsaturated amides such as (meth) acrylamide, N-alkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide; Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as methyl vinyl ether and ethyl vinyl ether ; Ethylene, propylene, etc. -Olefins; Halogen-containing α, β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride; α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene One or more of these monomers can be used. Examples of the alkyl include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, a 2-ethylhexyl group, and a cyclohexyl group.

The isocyanate compound used as the crosslinking agent is a compound having an isocyanate derivative structure represented by isocyanate or blocked isocyanate. Examples of the isocyanate include aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate; and aromatic rings such as α, α, α ′, α′-tetramethylxylylene diisocyanate. Aliphatic isocyanates; aliphatic isocyanates such as methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate; cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), isopropylidene dicyclohexyl diisocyanate Ne Alicyclic isocyanates such as bets are exemplified.

In addition, polymers and derivatives such as burettes, isocyanurates, uretdiones, and carbodiimide modified products of these isocyanates are also included. These may be used alone or in combination. Among the above isocyanates, aliphatic or alicyclic isocyanates are more preferable than aromatic isocyanates in order to avoid yellowing due to ultraviolet rays.

When used in the state of blocked isocyanate, the blocking agent includes, for example, bisulfites, phenolic compounds such as phenol, cresol, and ethylphenol, and alcohols such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol, and ethanol. Compounds, active methylene compounds such as dimethyl malonate, diethyl malonate, methyl isobutanoyl acetate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, mercaptan compounds such as butyl mercaptan, dodecyl mercaptan, ε-caprolactam, δ-valerolactam, etc. Lactam compounds, amine compounds such as diphenylaniline, aniline, ethyleneimine, acetanilide, acetic acid amide acid amide compounds, Examples include oxime compounds such as rumaldehyde, acetoaldoxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime, and these may be used alone or in combination of two or more. Among these, an isocyanate compound blocked with an active methylene compound is particularly preferred from the viewpoint of adhesion to a substrate film and wettability to the substrate film.

The above isocyanate-based compounds may be used alone or as a mixture or combination with various polymers. In the sense of improving the dispersibility and crosslinkability of the isocyanate compound, it is also preferable to use a mixture or a bond with a polyester resin or a urethane resin.

Examples of the epoxy compound used as the cross-linking agent include condensates of epichlorohydrin with ethylene glycol, polyethylene glycol, glycerin, polyglycerin, bisphenol A and other hydroxyl groups and amino groups, such as polyepoxy compounds and diepoxy compounds. Monoepoxy compounds, glycidylamine compounds, and the like. Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane. Polyglycidyl ether: As the diepoxy compound, for example, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether , Polypropylene glycol diglycidyl ether, poly Tetramethylene glycol diglycidyl ether; monoepoxy compounds such as allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and glycidyl amine compounds such as N, N, N ′, N′-tetraglycidyl-m-xyl Examples include range amine and 1,3-bis (N, N-diglycidylamino) cyclohexane.

The melamine compound used as the cross-linking agent is a compound having a melamine skeleton in the compound. For example, an alkylolized melamine derivative or an alkylolated melamine derivative is partially or completely etherified by reacting alcohol. Compounds, and mixtures thereof can be used. As alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are preferably used. Moreover, as a melamine compound, either a monomer or a multimer more than a dimer may be sufficient, or a mixture thereof may be used. In view of reactivity with various compounds, it is preferable that the melamine compound contains a hydroxyl group. Further, a product obtained by co-condensing urea or the like with a part of melamine can be used, and a catalyst can be used to increase the reactivity of the melamine compound.

The carbodiimide-based compound used as the crosslinking agent is a compound having one or more carbodiimide or carbodiimide derivative structures in the molecule. A polycarbodiimide compound having two or more carbodiimide structures in the molecule is preferred for better strength of the functional layer and the like.

The carbodiimide compound used as the crosslinking agent can be synthesized by a conventionally known technique, and generally a condensation reaction of a diisocyanate compound is used. The diisocyanate compound is not particularly limited, and any of aromatic and aliphatic compounds can be used. Specifically, tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, hexa Examples include methylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate, and dicyclohexylmethane diisocyanate.

Furthermore, in order to improve the water solubility and water dispersibility of the polycarbodiimide compound within a range not losing the effect of the present invention, a surfactant may be added, or a polyalkylene oxide or a quaternary ammonium salt of a dialkylamino alcohol. Hydrophilic monomers such as hydroxyalkyl sulfonates may be added and used.

The silane coupling compound used as the crosslinking agent is an organosilicon compound having a hydrolyzable group such as an organic functional group and an alkoxy group in one molecule. For example, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4- Epoxy group) epoxy group-containing compounds such as ethyltrimethoxysilane; vinyl group-containing compounds such as vinyltrimethoxysilane and vinyltriethoxysilane; styryl group-containing compounds such as p-styryltrimethoxysilane and p-styryltriethoxysilane; 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, etc. (Meth) acrylic group-containing compound; 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl)- 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldiethoxysilane, 3-triethoxysilyl-N -Amino group-containing compounds such as (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane; Tris (trimethoxysilylpropyl) Isocyanurate, tris (triethoxysilylpropyl) Isocyanurate group-containing compounds such as cyanurate; mercapto group-containing compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane It is done.

Among the above compounds, from the viewpoint of the strength of the functional layer and the adhesion to the substrate film, an epoxy group-containing silane coupling compound, a double bond-containing silane coupling compound such as a vinyl group or a (meth) acryl group, an amino group More preferred are silane coupling compounds.

In addition, the crosslinking agent contained in the functional layer usually exists in a state of reacting with the polymer or the crosslinking agent itself in the drying process or the film forming process. Therefore, the functional layer in the present laminated white film 1 exists as an unreacted product of these crosslinking agents, a compound after reaction, or a mixture thereof (compound derived from the crosslinking agent).

The lower limit of the content of the crosslinking agent in the functional layer is usually 0% by weight or more, preferably 3% by weight or more, more preferably 5% by weight or more, further preferably 8% by weight or more, and particularly preferably 10% by weight or more. . The upper limit is usually 80% by weight or less, preferably 70% by weight or less, more preferably 60% by weight or less, still more preferably 50% by weight or less, and particularly preferably 40% by weight or less. By using in the above range, it is possible to improve the strength of the functional layer, and also to improve the adhesion to the base film, and to improve the wettability to the base film when the functional layer is provided by coating Appearance tends to be achieved. Here, content of a crosslinking agent means the content rate in the non-volatile component in the raw material (coating liquid) before bridge | crosslinking reaction, and the same meaning is pointed out also in the functional layer after bridge | crosslinking reaction.

(Other ingredients)
In the range not impairing the gist of the present invention, the functional layer may contain particles for improving blocking and slipperiness. Further, the functional layer may contain an antifoaming agent, a coating property improver, a thickener, an organic lubricant, an ultraviolet absorber, an antioxidant, a foaming agent, and the like.

(Functional layer thickness)
The thickness of the functional layer is usually 0.001 to 3 μm, preferably 0.005 to 1 μm, more preferably 0.01 to 0.5 μm, still more preferably 0.02 to 0.3 μm, and most preferably 0.03. ~ 0.2 μm. By setting the film thickness of the functional layer in the above range, it tends to be easy to achieve both good antistatic performance and release performance.

(Functional layer layout)
The functional layer can be provided on one side of the polyester film as the base material, or can be provided on both sides of the polyester film.
When provided on both sides, the film can be used as a recording material on both sides, and there are advantages such as improved handling of the film. In addition, by providing the functional layer on both sides, the curling property due to environmental changes such as temperature and humidity tends to be improved.

(Antistatic performance of functional layer)
As the antistatic performance of the functional layer, the surface resistance value is usually 1 × 10 ¹³ Ω or less, preferably 1 × 10 ¹² Ω or less, more preferably 5 × 10 ¹¹ Ω or less, more preferably 1 × 10 ¹¹ Ω or less. Particularly preferably, it is 5 × 10 ¹⁰ Ω or less. When it is within the above range, the film tends to be effective for preventing sticking between films and preventing adhesion of dust and the like. For this reason, when used as a recording material for copying paper and printer paper that can transfer toner images suitably by methods such as electrophotography and thermal transfer, prevention of double feeding in paper transportation of copying machines and multifunction devices, It becomes possible to prevent sticking between sheets.

<The manufacturing method of this laminated white film 1>
Hereinafter, the manufacturing method of the present laminated white film 1 will be specifically described. However, the present invention is not particularly limited to the following examples as long as the gist of the present invention is satisfied.

First, dry or undried raw materials blended by a known method are supplied to a melt extrusion apparatus, heated to a temperature equal to or higher than the melting point of each polymer, and melt kneaded. The molten polymer is then directed to a die to produce a molten sheet.
In addition, when manufacturing the polyester film laminated | stacked on two or more layers, the raw material mix | blended for each layer is supplied to each melt-extrusion apparatus, and it heat-melts and kneads to the temperature which is more than melting | fusing point of each polymer. The molten polymer of each layer is then directed and laminated to the die, usually through a multi-manifold or feed block.
Next, the molten sheet extruded from the die is rapidly cooled and solidified on the rotary cooling drum so as to have a temperature equal to or lower than the glass transition temperature, thereby obtaining a substantially amorphous unoriented sheet. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably employed.

¡The sheet obtained as described above is stretched to form a film. Fine independent cavities contained in the polyester film are generated by such stretching.

The stretching conditions will be specifically described. The unstretched sheet is preferably stretched 2.5 to 5 times at 70 to 150 ° C. in the longitudinal direction (longitudinal direction) to form a longitudinally uniaxially stretched film. A longitudinally uniaxially stretched film is stretched 3 to 5 times at 70 to 160 ° C. in the width direction (lateral direction), and is usually 200 to 250 ° C., preferably 210 to 240 ° C., more preferably 215 to 240 ° C. The heat treatment is usually performed for 5 to 600 seconds, preferably 8 to 300 seconds.
By adjusting the heat treatment temperature within such a temperature range, the melt viscosity of the polymer incompatible with the polyester can be adjusted, and the roughness of the film surface can be adjusted.

The various conditions of the heat treatment step affect not only the heat shrinkage rate of the film but also the arithmetic average roughness (Ra) of the film surface. That is, by setting the temperature within the above range, in the case of a surface or a laminated structure, fine cavities formed by a polymer incompatible with the polyester existing on the surface layer are dissolved. By appropriately reducing the surface roughness, it is possible to easily peel and remove characters and images formed on the film surface by printing. This makes it possible to repeatedly use the film as a recording material for copying paper and printer paper.

After the heat treatment step, a method of relaxing 2 to 20% in the longitudinal direction and / or the transverse direction in the maximum temperature zone of the heat treatment and / or the cooling zone at the heat treatment outlet is preferable. Further, it is possible to add re-longitudinal stretching and re-lateral stretching as necessary.

(Method for forming functional layer)
The polyester film obtained by the above-described production method has a functional layer laminated on at least one side.
The functional layer can be provided by various known methods such as a coating method, a coextrusion method, and a transfer method. Of these, coating is preferred from the viewpoint of efficient production and performance.

Examples of the coating method include gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze coating, impregnation coating, kiss coating, and spray coating. Conventionally known coating methods such as calendar coating and extrusion coating can be used.
The functional layer may be provided by in-line coating, which treats the film surface during the process of forming the polyester film, or may employ offline coating that is applied outside the system on the once produced film. Among them, the functional layer is more preferably formed by in-line coating.

In-line coating is a method of coating within the process of manufacturing a polyester film, and specifically, a method of coating at any stage from melt extrusion of a polyester to heat setting after stretching and winding up. Usually, it is coated on any of an unstretched sheet obtained by melting and quenching, a stretched uniaxially stretched film, a biaxially stretched film before heat setting, and a film after heat setting and before winding. Although not limited to the following, for example, in sequential biaxial stretching, a method of stretching in the width direction (lateral direction) after coating a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction) is particularly excellent. According to this method, film formation and functional layer formation can be performed at the same time, so there is an advantage in manufacturing cost. In addition, in order to perform stretching after coating, the thickness of the functional layer can be changed by the stretching ratio. Compared to offline coating, thin film coating can be performed more easily. Further, by providing the functional layer on the film before stretching, the functional layer can be stretched together with the base film, whereby the functional layer can be firmly adhered to the base film.
Furthermore, in the production of a biaxially stretched polyester film, the film can be restrained in the longitudinal and lateral directions by stretching while gripping the film end with a clip, etc. High temperature can be applied while maintaining the properties. Therefore, if in-line coating is performed, the heat treatment performed after application can be performed at a high temperature that cannot be achieved by other methods, so that the film-forming property of the functional layer is improved and the functional layer and the base film are made stronger. In addition, the functional layer can be made strong, the functional layer can be prevented from falling off, and the antistatic performance and the release performance can be improved. Moreover, when forming a functional layer using the raw material (coating liquid) containing a crosslinking agent, a crosslinking reaction can be performed by the high temperature at the time of heat setting.

The functional layer is formed by coating the polyester film with a solution prepared by using the above-described series of compounds as a solution or solvent dispersion and adjusting the solid content concentration to about 0.1 to 80% by weight. It is preferable to produce a laminated white film. In particular, when provided by in-line coating, an aqueous solution or a water dispersion is more preferable. For the purpose of improving the dispersibility in water, improving the film-forming property, etc., the coating solution may contain a small amount of an organic solvent. Moreover, only one type of organic solvent may be used, and two or more types may be used as appropriate.

The drying and curing conditions for forming the functional layer are not particularly limited, but in the case of the coating method, the drying temperature of a solvent such as water used in the coating solution is usually 70 to 150 ° C., preferably Is 80 to 130 ° C, more preferably 90 to 120 ° C. The drying time is generally 3 to 200 seconds, preferably 5 to 120 seconds.
In order to improve the strength of the functional layer, it is preferable that a heat treatment step in the range of usually 150 to 270 ° C., preferably 170 to 250 ° C., more preferably 180 to 240 ° C. is performed in the film manufacturing process. The time for the heat treatment step is generally 5 to 600 seconds, preferably 8 to 300 seconds.

Further, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination as necessary. The polyester film constituting the laminated white film 1 may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

<Image-forming substances, etc.>
The laminated white film 1 can be provided with characters and images containing a thermoplastic resin such as an image forming substance on the functional layer.

Here, the character and the image can be provided by a conventionally known method, and can be obtained by printing with a copying machine or a printer.
On the other hand, conventionally known materials can also be used for thermoplastic resins used for image forming substances and the like.
There is no limitation on the image forming substance. That is, the above-mentioned “image forming substance” generally includes all substances capable of forming an image on a recording material, and may have any property such as solid particles, suspension, solution, etc. Ink is also included.
The colorant is not limited, and any of pigments, dyes, colored compounds and the like can be used. Among these, a toner in which a pigment is dispersed in a thermoplastic resin to form a fine particle is preferable.

<Resin layer>
The laminated white film 1 can further be provided with a resin layer on the image forming substance or the like or on the functional layer.
The main purpose of the resin layer may be to remove characters and images from the film together with the resin layer in order to reuse the laminated white film.

As this resin layer, conventionally known materials can be used, and a curable resin layer formed from a curable resin composition is preferable.
Examples of the curable resin layer include a thermosetting resin layer made of a resin composition that is cured by heating, an active energy ray curable resin layer made of a resin composition that is cured by irradiation with active energy rays, and the like. Can be mentioned. Among these, the active energy ray-curable resin layer is preferable from the viewpoint that it is easy to peel off and remove all characters and images.

Examples of the active energy ray curable resin layer include an ultraviolet curable resin layer, an electron beam curable resin layer, and a visible light curable resin layer. In view of ease of handling and curable performance, the ultraviolet curable resin layer is preferable. An example of the active energy ray-curable resin layer is a hard coat layer.

The material used for the active energy ray-curable resin layer is not particularly limited. Examples thereof include cured products such as reactive silicon compounds such as monofunctional (meth) acrylates, polyfunctional (meth) acrylates, and tetraethoxysilane. Among these, from the viewpoint of achieving both productivity and hardness, a polymerization cured product of a composition containing an active energy ray-curable (meth) acrylate is particularly preferable. Moreover, when providing the said resin layer in order to peel and remove an image from a lamination | stacking white film, it exists in the tendency which can exhibit a favorable peeling removal characteristic by using said material.

The composition containing the active energy ray-curable (meth) acrylate is not particularly limited. For example, a known monofunctional (meth) acrylate, a bifunctional (meth) acrylate, a mixture of one or more polyfunctional (meth) acrylates, a commercially available resin material for an active energy ray-curable hard coat, or these In addition to this, what added the other component can be used in the range which does not impair the objective of this embodiment.

The active energy ray-curable monofunctional (meth) acrylate is not particularly limited. For example, alkyl (meth) acrylate such as methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, etc. Hydroxyalkyl (meth) acrylate such as meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxypropyl (meth) ) Acrylate, alkoxyalkyl (meth) acrylate such as ethoxypropyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) Aromatic (meth) acrylates such as acrylate, phenoxypropyl (meth) acrylate, amino group-containing (meth) acrylates such as diaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, methoxyethylene glycol (meth) acrylate, phenoxypolyethylene Examples include ethylene oxide-modified (meth) acrylates such as glycyl (meth) acrylate and phenylphenol ethylene oxide-modified (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and (meth) acrylic acid.

The active energy ray-curable bifunctional (meth) acrylate is not particularly limited. For example, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tricyclodecanedi Alkanediol di (meth) acrylate such as methylol di (meth) acrylate, bisphenol A ethylene oxide modified di (meth) acrylate, bisphenol F ethylene oxide modified di (meth) acrylate and other bisphenol modified di (meth) acrylate, polyethylene glycol di (Meth) acrylate, polypropylene glycol di (meth) acrylate, urethane di (meth) acrylate, epoxy di (meth) acrylate and the like.

The active energy ray-curable polyfunctional (meth) acrylate is not particularly limited, and examples thereof include dipentaerythritol hexa (meth) acrylate, pentaerythritol tetra (meth) acrylate, and ditrimethylolpropane tetra (meth) acrylate. , Isocyanuric acid modified tri (meth) such as pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, ε-caprolactone modified tris (acryloxyethyl) isocyanurate Acrylate, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate Tan prepolymers, urethane acrylates such as dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, and the like.

Other components contained in the composition containing the active energy ray-curable (meth) acrylate are not particularly limited. Examples thereof include inorganic or organic fine particles, polymerization initiators, polymerization inhibitors, antioxidants, antistatic agents, dispersants, surfactants, light stabilizers, and leveling agents. In addition, when the film is dried after film formation in the wet coating method, an arbitrary amount of solvent can be added.

When a resin layer is provided for peeling and removing characters and images from a laminated white film, the peeling and removing process is usually performed in an office or the like, not in a factory that manufactures the film. For this reason, it is preferable not to contain a solvent for indoor use such as in an office. As the resin (resin liquid) for forming the resin layer, the content of the solvent is preferably 10% by weight or less, more preferably 5% by weight or less, further preferably 3% by weight or less, and particularly preferably 1% by weight or less. Most preferably, it does not contain a solvent (does not intentionally contain it).

Examples of the method for forming the resin layer include a general wet coating method such as a roll coating method and a die coating method, and an extrusion method. The formed resin layer can be subjected to a curing reaction by heating, irradiation with active energy rays such as ultraviolet rays and electron beams as necessary.

<< Second Embodiment >>
As an example of a second embodiment for carrying out the present invention, a laminated white polyester film (also referred to as “laminated white film”) 10 will be described.

<Laminated white polyester film 10>
A laminated white polyester film 10 (referred to as “the present laminated white polyester film 10”) as an example for carrying out the present invention is a laminated film having at least two layers containing polyester as a main component resin. At least the surface layer is characterized by containing polyester and a polymer incompatible with the polyester.

<Laminated structure>
The laminated structure of the laminated white polyester film 10 may be a multilayer of two layers, three layers, four layers or more as long as it does not exceed the gist of the present invention, and is not particularly limited. Among these, a three-layer structure (surface layer / intermediate layer / surface layer) composed of both surface layers and an intermediate layer is preferable.
In addition, the case where a laminated structure is two layers means that it is comprised by two surface layers, and specifically, 2 of the composition from which mixing | blending of the kind of polyester which comprises each layer, the particle | grains to contain, etc. differs. The case where it forms with a layer is mentioned.

<Surface>
The surface layer of the laminated white polyester film 10 preferably contains at least a polyester as a main component resin and a polymer incompatible with the polyester.
Here, the “main component resin” means a resin having the largest content ratio among the resin components constituting the surface layer. It can be assumed that the main component resin occupies 30% by mass or more, particularly 50% by mass or more, particularly 80% by mass or more (including 100% by mass) of the resin components constituting the surface layer.

(polyester)
The polyester constituting the laminated white polyester film 10 is the same as the polyester as the base material in the laminated white film 1 or the polyester as the main component resin of the polyester resin layer.

(Polyester incompatible with polyester)
By including a polymer incompatible with the polyester in the laminated white polyester film 10, the polyester film stretched at least in a uniaxial direction can contain innumerable fine cavities. Due to the fine cavities, the laminated white polyester film 10 not only scatters light and causes white opacity, but also reduces the apparent density of the laminated white polyester film 10.
In particular, the surface layer of the laminated white polyester film 10 contains a polymer that is incompatible with polyester, so that the toner printed on the surface of the laminated white polyester film 10 when used as a recording material for copying paper or printer paper, etc. Thus, the image forming substance containing the thermoplastic resin can be easily peeled and removed. Moreover, in order to ensure sufficient concealability and weight reduction, a polymer incompatible with the polyester may be contained in the intermediate layer as necessary.

The polymer incompatible with the polyester is the same as the “polymer incompatible with the polyester” described in the laminated white film 1 described above.

The lower limit of the content of the “polyester incompatible polymer” in the surface layer of the laminated white polyester film 10 is usually 1% by weight or more, preferably 2% by weight or more, more preferably 3% by weight or more, and further preferably 5%. % By weight or more, particularly preferably 8% by weight or more. By using in the above range, the amount of fine cavities generated in the film becomes sufficient, the concealability of the film is improved, and the effect of reducing the apparent density, that is, the weight reduction is sufficient. In addition, the slipperiness of the film and the writing property of a pencil or the like are improved, which is advantageous for the print transportability. Furthermore, on the film surface, it becomes easy to peel off and remove characters and images from printed image forming substances and the like, and there is a tendency that the film can be repeatedly used as a recording material for copying paper or printer paper.
On the other hand, the upper limit of the content of the polymer incompatible with the polyester in the surface layer is usually 70% by weight or less, preferably 50% by weight or less, more preferably 40% by weight or less, still more preferably 35% by weight or less, particularly preferably. 30% by weight or less, most preferably 25% by weight or less. By using in this range, the amount of cavities to be generated is not too large, and there is a tendency to easily suppress breakage during stretching.

Further, the lower limit of the content of the “polyester incompatible with polyester” in each layer of the laminated white polyester film 10 is usually 1% by weight or more, preferably 2% by weight or more, more preferably 3% by weight or more, and further preferably. Is 5% by weight or more, particularly preferably 8% by weight or more. By using it in the above range, it has sufficient concealing property, and the effect of reducing the apparent density, that is, the weight reduction can be sufficient.
On the other hand, the upper limit of the content of the polymer incompatible with the polyester in each layer of the laminated white polyester film 10 is usually 70% by weight or less, preferably 50% by weight or less, more preferably 40% by weight or less, and further preferably 35% by weight. % Or less, particularly preferably 30% by weight or less, and most preferably 25% by weight or less. By using in this range, the amount of cavities to be generated is not too large, and there is a tendency to easily suppress breakage during stretching.

When the present laminated white polyester film 10 has a structure of three or more layers, the intermediate layer is a range that does not impair the gist of the present invention, such as an ear part, a master roll ear part, and a master roll lower winding part generated during film production. You may mix with. The inclusion of recycled products has the effect of reducing costs and reducing environmental impact. The content of the recycled product in the intermediate layer is preferably 95% by weight or less, more preferably 85% by weight or less with respect to the intermediate layer from the viewpoint of film formation stability due to a decrease in intrinsic viscosity in addition to color tone regulation. More preferably, it is 70% by weight or less, particularly preferably 60% by weight or less, most preferably 40% by weight or less.

(Metal compound particles)
The laminated white polyester film 10 may contain metal compound particles for the purpose of further improving the concealability and whiteness. When the polyester film has a structure of three or more layers, the layer containing the metal compound particles may be a surface layer or an intermediate layer. In order to effectively improve the concealability and whiteness, it is preferably contained in the surface layer.

The metal compound particles used in the laminated white polyester film 10 tend to compensate for the white opacity due to the light scattering effect generated by fine cavities by blending incompatible polymers. It tends to get a degree.

At this time, the metal compound particles are the same as the metal compound particles described in the laminated white film 1.

The lower limit of the content of the metal compound particles is preferably 1% by weight or more, more preferably 2% by weight or more, and further preferably 3% by weight with respect to the entire surface layer of the laminated white polyester film 10 containing the metal compound particles. The upper limit is usually 30% by weight or less, preferably 20% by weight or less, more preferably 15% by weight or less, still more preferably 13% by weight or less, and particularly preferably 10% by weight or less. By making it in the above range, a sufficient degree of concealment can be given, and it is also advantageous in terms of cost, and it is optimal to use it as a recording material for copy paper or printer paper instead of paper made of paper. It tends to be a thing.

(Particles other than metal compound particles)
In order to improve the handleability and the slipperiness of the present laminated white polyester film 10, in particular, the surface layer of the present laminate white polyester film 10 includes particles other than the metal compound particles exemplified above for imparting slipperiness. It may be.

At this time, the particles other than the metal compound particles are the same as the “particles other than the metal compound particles” described in the laminated white film 1.

(Other ingredients)
In the present laminated white polyester film 10, in addition to the above-described particles and polymers incompatible with polyester, conventionally known antioxidants, heat stabilizers, lubricants, antistatic agents, fluorescent whitening agents, Dyes, pigments and the like can be added. Further, depending on the use, an ultraviolet absorber, particularly a benzoxazinone-based ultraviolet absorber may be contained.

<Laminated structure>
As described above, the laminated white polyester film 10 is a laminated film having at least two layers containing polyester as a main component resin, and at least a surface layer of the laminated white polyester film 10 contains a polyester and a polymer incompatible with the polyester. In addition, the arithmetic average roughness (Ra) of the surface layer is preferably 950 nm or less.
If the surface layer contains polyester and a polymer that is incompatible with the polyester as described above, a fine cavity can be provided by stretching, so that weight reduction, concealability, and whitening can be realized. Since the surface roughness can be further adjusted, the writing property can be improved.

If the surface layer further contains metal compound particles, the hiding property and whiteness can be further increased, and the slipperiness can be improved by containing particles other than the metal compound particles.

As long as the intermediate layer other than the surface layer contains the polyester, a polymer incompatible with the polyester, metal compound particles, and particles other than the metal compound particles may be contained as necessary. It is preferable from the viewpoint of cost reduction and environmental load reduction that the content of the metal compound particles and particles other than the metal compound particles is made as small as possible, and the recycled polyester is used.

<Thickness>
The thickness of the laminated white polyester film 10 is not particularly limited as long as it can be formed as a film. The thickness is preferably 10 to 1000 μm, more preferably 20 to 500 μm, even more preferably 30 to 400 μm, and particularly preferably 38 to 350 μm. By using in the said range, it becomes possible to make the firmness and handleability of a film sufficient.

In the laminated white polyester film 10, the metal compound particles and particles other than the metal compound particles are preferably contained in the surface layer.
In addition, in order to reduce costs and reduce environmental impact by adding recycled products to the intermediate layer, it is preferable to use a coextrusion method to form a laminated structure.
From this point of view, when the polyester film has a laminated structure of three or more layers as described above, the thickness of each surface layer is preferably 1 μm to 50 μm, especially 2 μm or more or 40 μm or less, especially 3 μm or more or 30 μm. Hereinafter, among them, the thickness is more preferably 4 μm or more or 25 μm or less. By using in the said range, it becomes possible to fully exhibit the performance by the metal compound particle | grains mentioned later and particle | grains other than metal compound particle | grains, and manufacturing cost can also be suppressed at low cost.

<Apparent density>
The lower limit of the apparent density of the laminated white polyester film 10 is usually 0.7 g / cm ³ or more, preferably 0.75 g / cm ³ or more, more preferably 0.8 g / cm ³ or more. By setting the above range, the strength of the film can be maintained, and clogging of the film in the transport process in the copying machine when used as a recording material in place of copying paper or printer paper as an information printing medium can be reduced. This makes it possible to perform optimal printing.
On the other hand, the upper limit is usually 1.3 g / cm ³ or less, preferably 1.2 g / cm ³ or less, more preferably 1.1 g / cm ³ or less. By setting it as the above range, the work burden when carrying a large amount of printed matter is reduced, and furthermore, it is possible to reduce environmental load and reduce costs by reducing CO ₂ generated in the film (sheet) transportation process.
The apparent density of the polyester film can be adjusted by blending an incompatible polymer having a specific gravity lighter than that of the polyester as the main component resin and stretching in at least a uniaxial direction. However, it is not limited to these methods.

<Physical properties>
The arithmetic average roughness (Ra) of the surface, that is, the surface layer of the laminated white polyester film 10 is preferably 950 nm or less, more preferably 850 nm or less, and particularly preferably 800 nm or less. By using the arithmetic average roughness (Ra) within the above range, characters and images such as image forming substances containing thermoplastic resin formed on the film surface by printing can be easily peeled and removed. Tends to be repeatedly used as a recording material for copying paper and printer paper.
On the other hand, the lower limit of the arithmetic average roughness (Ra) is preferably 100 nm or more, more preferably 200 nm or more, more preferably 300 nm or more, and particularly preferably 350 nm or more. By setting it within the above range, it is possible to make the concealability and transportability sufficient, and it is possible to obtain an optimum film for use as a recording material for copying paper and printer paper. Furthermore, it exists in the tendency which can have sufficient writing property.
In addition, the arithmetic mean roughness (Ra) in this invention shall be based on the measuring method used in the Example mentioned later.

The b value (reflection method) which is an index representing the yellowness of the laminated white polyester film 10 is usually 0.00 or less, preferably −0.20 or less, more preferably −0.40 or less, and further preferably −0. .50 or less, particularly preferably −0.60 or less, and the lower limit is not particularly limited, but is preferably −5.0 or more. By using in the said range, yellowness can be suppressed and whiteness can be made favorable. Further, when used as a recording material for color printing, the obtained image quality tends to be excellent.

In the laminated white polyester film 10, the heat shrinkage in the film longitudinal direction (MD) and the film width direction (TD) at 150 ° C. for 30 minutes is usually 2.8% or less, preferably 2.3% or less as an absolute value. More preferably, it is 2.0% or less.
If the heat shrinkage is in the above range, it is possible to prevent the dimensional stability of the film from being impaired due to the influence of heat when printing on a recording material by a method such as an electrophotographic method or a thermal transfer method. Even at the edge of the (sheet), that is, the portion where wrinkles are likely to occur, the generation of wrinkles can be suppressed, and the phenomenon of distortion and unevenness in characters and images can be suppressed and image quality can be reduced. It becomes possible. In addition, since wrinkles cannot be erased once they occur, they cannot be repeatedly used as a recording material for copying paper or printer paper, and therefore it is preferable that wrinkles are not generated as much as possible.

The concealability (OD) of the present laminated white polyester film 10 is usually 0.30 or more, preferably 0.35 or more, more preferably 0.40 or more, even more preferably, when a single film is measured with a Macbeth densitometer. 0.45 or more. By using it in the above range, the show-through when the entire surface is printed on both sides of the film is reduced, and high quality characters and images can be obtained. On the other hand, the upper limit of the concealability (OD) is not particularly limited, but considering the balance of other physical properties, 1.0 or less is preferable, and 0.9 or less is more preferable.

The whiteness of the laminated white polyester film 10 is determined by measuring the Hunter whiteness (Wb) when the film is a single sheet with a colorimeter, and the lower limit is usually 80.0% or more, preferably 81.0% or more. Preferably it is 82.0% or more, More preferably, it is 83.0% or more, Most preferably, it is 83.5% or more. By setting the whiteness to the above range, high-definition characters and images can be used as recording materials for copy paper and printer paper, which are information printing media that replace paper, especially when color printing is performed. Therefore, it tends to be preferable in terms of quality. Moreover, since it depends also on the use to be used, in order to give a high-class feeling, a higher one is preferable, and the upper limit is not particularly limited. On the other hand, when used in applications where gloss is a concern, the upper limit of the preferred range is 95.0% or less.

<Functional layer>
A functional layer may be provided on at least one side of the laminated white polyester film 10.
This functional layer can serve as a recording layer on which the image forming substance adheres directly to the layer surface, for example. The recording layer in the present invention is a layer that not only fixes the attached image forming substance but also has a role of removing the image forming substance together with the resin layer when a resin layer described later is provided.

The functional layer preferably has antistatic performance and release performance.
The laminated white polyester film 10 has a reduced apparent density, can be whitened without cost, and can easily peel and remove characters and images such as image forming substances containing a printed thermoplastic resin. It is preferable to provide a polyester resin layer containing polyester and a polymer incompatible with polyester, and it is more preferable that the polyester resin layer has a surface layer. However, when a functional layer is provided, it has been found that it tends to be difficult to express the ability to easily peel and remove characters and images such as image forming substances on the surface layer. It is preferable that performance is also provided. That is, the functional layer is provided in order to provide a release performance so that characters and image forming substances such as toner containing a thermoplastic resin formed on the film surface can be suitably peeled and removed after printing. Preferably contains a release agent.

This laminated white polyester film 10 is used as a recording material for copying paper and printer paper that can transfer a toner image suitably by a system such as an electrophotographic system or a thermal transfer system, and prevents double feeding in the paper transport of a copier / multifunction machine. The purpose is to prevent sticking between sheets when handling the sheets. Furthermore, it is preferable that the functional layer has an antistatic performance in order to prevent the adhesion of dust and to obtain a high-quality film or a high-quality film print.
From this viewpoint, it is preferable to have a functional layer containing an antistatic agent on at least one side.

In order to improve the ease of forming an image forming substance and fixability, and to improve the wettability to the base film when the functional layer is provided by coating, the functional layer is a polymer (antistatic agent described above). It is further preferable to contain a polymer other than the release agent.

By adding an antistatic agent, a release agent and a polymer to the functional layer and imparting an appropriate release performance, the function of fixing the image forming substance on the film surface and the image forming substance are peeled and removed. It has been found that functions can be obtained more appropriately. That is, the present inventors have found a technique for realizing the mutually contradictory characteristics of fixability and peelability with a single functional layer. This technology can be said to be a highly effective technology considering that a functional layer having general fixing performance cannot achieve peeling performance, while a functional layer having general peeling performance cannot realize fixing performance. . Moreover, even if a functional layer having fixing performance and a functional layer having peeling performance are laminated, any performance cannot be expressed, and only the performance of the functional layer corresponding to the outermost layer is reflected.

The antistatic agent, release agent and polymer used in the laminated white polyester film 10 are the same as the antistatic agent, release agent and polymer used in the laminated white film 1.

In addition, also when this laminated polyester film has the said functional layer, about the preferable value range of b value of this laminated polyester film, heat shrinkage rate, concealability (OD), and whiteness, it is the same as the above-mentioned numerical range. .

<Manufacturing method>
Hereinafter, the method for producing the laminated white polyester film 10 will be specifically described. The present invention is not particularly limited to the following examples as long as the gist of the present invention is satisfied.

First, raw materials blended for each layer which are dried or not dried by a known method are supplied to each melt-extrusion apparatus, heated to a temperature equal to or higher than the melting point of each polymer, and melt-kneaded. The molten polymer of each layer is then directed and laminated to the die, usually through a multi-manifold or feed block.
Next, the molten sheet extruded from the die is rapidly cooled and solidified on the rotary cooling drum so as to have a temperature equal to or lower than the glass transition temperature, thereby obtaining a substantially amorphous unoriented sheet. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably employed.

Specifically describing stretching conditions, the unstretched sheet is preferably stretched 2.5 to 5 times at 70 to 150 ° C. in the longitudinal direction (longitudinal direction) to form a longitudinally uniaxially stretched film, and then the width direction ( The film is stretched 3 to 5 times in the transverse direction at 70 to 160 ° C., usually in the range of 200 to 250 ° C., preferably 210 to 240 ° C., more preferably 215 to 240 ° C., usually 5 to 600 seconds, preferably 8 It is preferable to perform a heat treatment for up to 300 seconds.

The conditions of the heat treatment step affect not only the heat shrinkage rate of the film but also the arithmetic average roughness (Ra) of the surface layer of the film. That is, by setting the temperature within the above range, fine cavities formed by a polymer incompatible with the polyester present on the surface of the surface layer are dissolved. By appropriately reducing the surface roughness, it is possible to easily peel and remove characters and images such as an image forming substance containing a thermoplastic resin formed on the film surface by printing. This makes it possible to repeatedly use the film as a recording material for copying paper and printer paper.

A method for forming a functional layer on the laminated white polyester film 10 will be described below. The functional layer can be provided by various known methods such as a coating method, a coextrusion method, and a transfer method. Among them, the coating method is preferable from the viewpoint of efficient production and imparting performance.

As the above-mentioned coating method, the film surface may be provided by in-line coating, which is processed during the process of forming the polyester film, or off-line coating may be employed that is applied outside the system on the manufactured film. . More preferably, it is formed by in-line coating.

In-line coating is a method of coating in the process of manufacturing a polyester film, and specifically, a method of coating at an arbitrary stage from melt-extrusion of polyester to heat-fixing and winding after stretching. Usually, it is coated on any of an unstretched sheet obtained by melting and quenching, a stretched uniaxially stretched film, a biaxially stretched film before heat setting, and a film after heat setting and before winding. Although not limited to the following, for example, in sequential biaxial stretching, a method of stretching in the transverse direction after coating a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction) is particularly excellent. According to this method, film formation and functional layer formation can be performed at the same time, so there is an advantage in manufacturing cost. In addition, in order to perform stretching after coating, the thickness of the functional layer can be changed by the stretching ratio. Compared to offline coating, thin film coating can be performed more easily. Further, by providing the functional layer on the film before stretching, the functional layer can be stretched together with the base film, whereby the functional layer can be firmly adhered to the base film. Furthermore, in the production of a biaxially stretched polyester film, the film can be restrained in the longitudinal and lateral directions by stretching while gripping the film end with a clip, etc. High temperature can be applied while maintaining the properties. Therefore, since the heat treatment performed after coating can be performed at a high temperature that cannot be achieved by other methods, the film forming property of the functional layer can be improved, and the functional layer and the base film can be more firmly adhered to each other. In addition, the functional layer can be made strong, preventing the functional layer from falling off, and improving the antistatic performance and the release performance.

<Image forming material>
Characters and images containing a thermoplastic resin such as an image-forming substance can be provided on the surface of the laminated white polyester film 10 where the functional layer is not provided or on the surface provided with the functional layer. It is.
Characters and images can be provided by a conventionally known method, and can be obtained by printing with a copying machine or a printer. Moreover, conventionally well-known materials can be used also about thermoplastic resins, such as an image forming substance.

<Resin layer>
The laminated white polyester film 10 can further be provided with a resin layer on characters and images containing a thermoplastic resin such as an image forming substance.
The main purpose of the resin layer may be to remove characters and images from the film together with the resin layer in order to reuse the laminated white polyester film.

A conventionally well-known material can be used as a resin layer, and it is preferable that it is a curable resin layer.
Examples of the curable resin layer include a thermosetting resin layer and an active energy ray curable resin layer. An active energy ray-curable resin layer is preferable from the viewpoint of easy separation and removal without leaving characters and images.

Although it does not specifically limit as a material used for an active energy ray curable resin layer, For example, hardened | cured material, such as reactive silicon compounds, such as monofunctional (meth) acrylate, polyfunctional (meth) acrylate, and tetraethoxysilane Can be mentioned. Among these, from the viewpoint of achieving both productivity and hardness, a polymerization cured product of a composition containing an active energy ray-curable (meth) acrylate is particularly preferable.

The composition containing the active energy ray-curable (meth) acrylate is not particularly limited. For example, a mixture of one or more known active energy ray-curable monofunctional (meth) acrylates, bifunctional (meth) acrylates, polyfunctional (meth) acrylates, and commercially available as an active energy ray-curable hard coat resin material In addition, those other than these may be used as long as the object of the present embodiment is not impaired.

The active energy ray-curable monofunctional (meth) acrylate is not particularly limited. For example, alkyl such as methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, etc. Hydroxyalkyl (meth) acrylate such as (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxypropyl ( Alkoxyalkyl (meth) acrylates such as meth) acrylate and ethoxypropyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) ) Aromatic (meth) acrylates such as acrylate, phenoxypropyl (meth) acrylate, amino group-containing (meth) acrylates such as diaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, methoxyethylene glycol (meth) acrylate, phenoxy Examples include polyethylene oxide (meth) acrylate, ethylene oxide modified (meth) acrylate such as phenylphenol ethylene oxide modified (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and (meth) acrylic acid. .

The active energy ray-curable polyfunctional (meth) acrylate is not particularly limited. For example, dipentaerythritol hexa (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, isocyanuric acid ethylene oxide modified tri Isocyanuric acid-modified tri (meth) acrylates such as (meth) acrylate, ε-caprolactone-modified tris (acryloxyethyl) isocyanurate, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urethane prepolymer, di Pentaerythritol pentaacrylate hexamethylene diisocyanate Urethane acrylates such as Tan prepolymer and the like.

It is preferable not to contain a solvent for indoor use such as in an office. As the resin (resin liquid) for forming the resin layer, the content of the solvent is preferably 10% by weight or less, more preferably 5% by weight or less, further preferably 3% by weight or less, and particularly preferably 1% by weight or less. Most preferably, the solvent is not contained (not intentionally contained).

<Explanation of phrases>
In the present invention, when “X to Y” (X and Y are arbitrary numbers) is described, it means “preferably greater than X” or “preferably Y” with the meaning of “X to Y” unless otherwise specified. It also includes the meaning of “smaller”.
Further, when described as “X or more” (X is an arbitrary number), it means “preferably larger than X” unless otherwise specified, and described as “Y or less” (Y is an arbitrary number). In the case, unless otherwise specified, the meaning of “preferably smaller than Y” is also included.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples unless it exceeds the gist. The measuring method used in the present invention is as follows. In addition, the various physical property in this invention, its measuring method, and a definition are as follows.

<Measurement method>
(1) Intrinsic viscosity of polyester 1 g of polyester from which other components such as polymer components and particles incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. And dissolved at 30 ° C.

(2) Melt flow index (MFI)
According to JIS K7210-1995, amorphous polyolefin was measured at 275 ° C. and 21.2 N, and polypropylene was measured at 230 ° C. and 21.2 N. Higher values indicate lower polymer melt viscosity.

(3) Arithmetic mean roughness (Ra)
Using a non-contact surface / layer cross-sectional shape measurement system VertScan (registered trademark) R550GML, manufactured by Ryoka System Co., Ltd., CCD camera: SONY HR-50 1/3 ′, objective lens: 20 ×, mirror Tube: 1X Body, Zoom lens: No Relay, Wavelength filter: 530 white, Measurement mode: Wave, measure 640 μm x 480 μm area, and use the output by fourth-order polynomial correction to calculate arithmetic mean roughness Ra value Obtained by averaging 10 points.

(4) Average particle size The particle size was measured by a sedimentation method based on Stokes' resistance law using a centrifugal sedimentation type particle size distribution analyzer SA-CP3 manufactured by Shimadzu Corporation. The average particle diameter was determined by using a value of 50% of integration (volume basis) in the equivalent spherical distribution of particles obtained by measurement.

(5) Film thickness of functional layer The surface of the functional layer was dyed with RuO ₄ and embedded in an epoxy resin. Thereafter, the section prepared by the ultrathin section method is stained with RuO ₄ , and the functional layer cross section is observed using a transmission electron microscope (H-7650, Hitachi High-Technologies Corporation, acceleration voltage 100 kV), and the film thickness is measured. did.

(6) Number average molecular weight It measured using the gel permeation chromatography (HLC-8120GPC by Tosoh Corporation). The number average molecular weight was calculated in terms of polystyrene.

(7) Heat Shrinkage The sample was treated for 30 minutes in an oven maintained at 150 ° C. in a tensionless state, the length of the sample before and after that was measured, and the heat shrinkage was calculated by the following equation.
Heat shrinkage rate (%) = {(L0−L1) / L0} × 100
(In the above formula, L0 is the sample length before the heat treatment, L1 is the sample length after the heat treatment)
Five points were measured in the film longitudinal direction (MD) and the width direction (TD), and the average value in each direction was determined.

(8) Surface resistance value Using a high resistance measuring instrument made by Hewlett-Packard Japan: HP4339B and measuring electrode: HP16008B, after fully conditioning the polyester film in a measurement atmosphere of 23 ° C. and 50% RH, the applied voltage was 100V. The surface resistance value of the functional layer after 1 minute was measured.

(9) Hunter whiteness Hunter whiteness (single film) using a colorimeter NDH-1001DP (C light source, 2 ° field of view) manufactured by Nippon Denshoku Industries Co., Ltd. according to the method of JIS P8123-1961 ( Wb) was measured. The back of the film was pressed with a black plate.

(10) b value (reflection method)
Using a colorimeter NDH-1001DP (C light source, 2 ° field of view) manufactured by Nippon Denshoku Industries Co., Ltd., the b value for a single film was measured according to the method of JIS Z-8722, 8730. The back of the film was pressed with a black plate.

(11) Concealment degree (OD)
Using a Macbeth densitometer TD-904, the transmission density with white light was measured. The measurement was performed at 5 points, and the average value was taken as the OD value. The larger this value, the lower the light transmittance.

(12) Apparent density (g / cm ³ )
A 10 cm × 10 cm square sample was cut out from an arbitrary part of the film, and the thickness was measured uniformly at 9 locations with a micrometer. From the average value and the weight of the film, the weight per unit volume was calculated as the apparent density. The number of measurements was 5 points, and the average value was used.

(13) Thickness of laminated white film A film piece was fixed and molded with an epoxy resin, then cut with a microtome, and the cross section of the film was observed with a transmission electron micrograph. Two of the cross-sections are observed in parallel with the film surface, and the interface is observed by light and dark. The distance between the two interfaces and the film surface was measured from 10 photographs, and the average value was taken as the thickness of the laminated white film.

(14) Image quality suitability by electrophotographic printing Ricoh Co., Ltd. MFP: A full-color test image on which an A4 size cut film (sheet) is fed to imagino MPC5001it and image forming substances are placed by photographic printing. Obtained. Image quality was evaluated as follows.

(Evaluation criteria)
A: High-definition, high-quality image without wrinkles on the film B: Some of the image quality is slightly blurred but no problem for practical use C: Wrinkles are generated on the film, and the image quality is also unclear Inferior.

(15) Character, image (toner image) peeling and removal appropriateness 95 parts by weight of UV curable resin (2-hydroxy-3-phenoxypropyl acrylate) on the film surface fixed with the image forming substance obtained in (14) A photopolymerization initiator (trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) is uniformly coated with a mixture of 5 parts by weight, a glass plate is placed on the mixture, and ultraviolet rays are irradiated on the mixture to cure ultraviolet rays. A resin layer was formed. Then, the glass plate and the film were peeled off. At this time, the formed ultraviolet curable resin layer adheres to the glass plate side, and can transfer and hold characters and images formed by an image forming substance formed on the film surface. The following evaluation was performed about the character and image peeling removal state on the film surface at this time.

(Evaluation criteria)
A: The image forming substance on the film surface can be completely removed, and it can be repeatedly used as a copy sheet.
B: Although a part of the image forming substance remains on the film surface, it can be used repeatedly as a copy sheet, and there is no practical problem.
C: Most of the image forming substance remains on the film surface and cannot be repeatedly used as copy paper.

(16) Print Conveyance Ricoh Co., Ltd. MFP: A film of the MFP when 100 sheets of A4 size cut film (sheet) are fed to imgioMPC5001it and 100 sheets are continuously printed by photographic printing. (Sheet) The transportability was evaluated as follows.

(Evaluation criteria)
A: There is no clogging of the film (sheet) in the multifunction machine. In addition, it was confirmed on the discharge tray of the multifunction machine that there was no occurrence of double feeding of printed films (sheets) and that each sheet could be conveyed independently.
B: Double feeding of printed film (sheet) occurs occasionally, but it is confirmed from the discharge tray of the multifunction device that there is no clogging of the film (sheet) in the multifunction device as long as there is no practical problem. .
C: Since several films are agglomerated by sticking films (sheets) together, the multifunction device cannot convey the film (sheet), or the film (sheet) is frequently clogged in the multifunction device and continuously printed. Even if it cannot be printed or barely printed, the image quality is unclear and overall poor.

(17) Writability
Five straight lines were drawn at intervals of 1 mm with a pencil having a hardness of Uni, manufactured by Mitsubishi Pencil Co., Ltd., and the following evaluation was performed visually.

(Evaluation criteria)
A: Individual straight lines can be identified.
B: The color of the line is light and individual lines are difficult to distinguish.
C: A straight line cannot be drawn.

(18) Appearance of functional layer The laminated white film was observed under a fluorescent lamp, and the appearance of the functional layer was visually evaluated as follows.

(Evaluation criteria)
A: Defects are not found in the functional layer and uniform appearance B: Defects are found in a part of the functional layers C: Defects are found in most of the functional layers

[Example 1 group]
As examples of the first embodiment, examples 1-1 to 1-69 and comparative examples 1-1 to 1-2 will be described.

<Functional layer>
The compounds constituting the functional layer are as follows.

・ Antistatic agent (compound with ammonium group): (IA)
Polymer polymerized with the following composition having a pyrrolidinium ring in the main chain: Diallyldimethylammonium chloride / dimethylacrylamide / N-methylolacrylamide = 90/5/5 (mol%). Number average molecular weight 30000.

・ Antistatic agent (compound having ammonium group): (IB)
A polymer compound having a number average molecular weight of 50000, wherein the counter ion is a methanesulfonic acid ion, comprising a structural unit of the following formula (2).

・ Releasing agent (long chain alkyl group-containing compound): (IIA)
200 parts by weight of xylene and 600 parts by weight of octadecyl isocyanate were added to a four-necked flask and heated with stirring. From the time when xylene began to reflux, 100 parts by weight of polyvinyl alcohol having an average polymerization degree of 500 and a saponification degree of 88 mol% was added in small portions over a period of about 2 hours. After the addition of polyvinyl alcohol, the reaction was completed by further refluxing for 2 hours. When the reaction mixture was cooled to about 80 ° C. and added to methanol, the reaction product was precipitated as a white precipitate. This precipitate was filtered off, and 140 parts by weight of xylene was added and heated to dissolve completely. Then, the operation of adding methanol again to cause precipitation was repeated several times, and then the precipitate was washed with methanol and dried and ground.

・ Release agent (polyether group-containing condensed silicone): (IIB)
Polyether group-containing silicone having a number average molecular weight of 7000 (silicone siloxane) containing 1 polyethylene glycol (terminated with a hydroxyl group) having an ethylene glycol chain of 8 with respect to dimethylsiloxane 100 in the dimethyl silicone side chain in a molar ratio. When the bond is 1, the ether bond of the polyether group is 0.07 at a molar ratio). A low molecular component having a number average molecular weight of 500 or less is 3% by weight, and there is no vinyl group (vinyl silane) or hydrogen group (hydrogen silane) bonded to silicon. In addition, this compound mix | blends the water which disperse | distributes sodium dodecyl benzenesulfonate in the ratio of 0.25 by making polyether group containing silicone 1 by weight ratio.

・ Release agent (wax): (IIC)
An emulsification facility with an internal capacity of 1.5 L equipped with a stirrer, thermometer, temperature controller, melting point 105 ° C., acid value 16 mgKOH / g, density 0.93 g / mL, number average molecular weight 5000 polyethylene oxide wax 300 g, ion-exchanged water 650 g 50 g of decaglycerin monooleate surfactant and 10 g of 48 wt% potassium hydroxide aqueous solution were added and replaced with nitrogen, sealed, stirred at 150 ° C. for 1 hour at high speed, cooled to 130 ° C., and the high-pressure homogenizer at 400 atm. A wax emulsion that has been passed through and cooled to 40 ° C.

・ Acrylic resin: (III)
Emulsion polymer of ethyl acrylate / n-butyl acrylate / N-methylol acrylamide / acrylic acid = 88/10/1/1 (wt%) (emulsifier: nonionic surfactant)

・ Crosslinking agent (oxazoline compound): (IVA)
Acrylic polymer having an oxazoline group and a polyalkylene oxide chain EPOCROS (registered trademark) (Oxazoline group amount = 4.5 mmol / g, manufactured by Nippon Shokubai Co., Ltd.)

・ Crosslinking agent (isocyanate compound): (IVB)
1000 parts by weight of hexamethylene diisocyanate was stirred at 60 ° C., and 0.1 part by weight of tetramethylammonium caprylate was added as a catalyst. Four hours later, 0.2 parts by weight of phosphoric acid was added to stop the reaction, and an isocyanurate type polyisocyanate composition was obtained. 100 parts by weight of the obtained isocyanurate-type polyisocyanate composition, 42.3 parts by weight of methoxypolyethylene glycol having a number average molecular weight of 400, and 29.5 parts by weight of propylene glycol monomethyl ether acetate were charged and maintained at 80 ° C. for 7 hours. Thereafter, the temperature of the reaction solution is maintained at 60 ° C., 35.8 parts by weight of methyl isobutanoyl acetate, 32.2 parts by weight of diethyl malonate, and 0.88 parts by weight of a 28 wt% methanol solution of sodium methoxide are added and maintained for 4 hours. did. Block polyisocyanate with active methylene obtained by adding 58.9 parts by weight of n-butanol and maintaining the reaction solution temperature at 80 ° C. for 2 hours and then adding 0.86 parts by weight of 2-ethylhexyl acid phosphate.

・ Crosslinking agent (hexamethoxymethylolmelamine): (IVC)

[Example 1-1]
Main vented biaxial with 80 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.67 dl / g and 20 parts by weight of a crystalline polypropylene homopolymer chip having a melt flow index of 10 ml / 10 min. Crystal in an extruder containing 15 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g and containing 50% by weight of titanium oxide particles having an average particle diameter of 0.32 μm for the surface layer, and a melt flow index of 8 ml / 10 min. 10 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g, containing 15% by weight of a conductive polypropylene homopolymer chip, 3.5% by weight of silica particles having an average particle size of 4.1 μm, and an intrinsic viscosity of 0.69 dl / g 280 parts by weight of polyethylene terephthalate chip of 280 g It was fed to a sub-vented twin screw extruder set at ℃. Through a gear pump and a filter, the polymer from the main extruder is an intermediate layer, and the polymer from the sub-extruder is the surface layer. The two layers and three layers (surface layer / intermediate layer / surface layer) are co-extruded from the die. Extrusion and rapid solidification on a cooling roll having a surface temperature set at 30 ° C. using an electrostatic application adhesion method, yielding a substantially amorphous sheet having a thickness of 887 μm.

The obtained amorphous sheet was stretched 3.1 times in the longitudinal direction at 92 ° C., and then the aqueous coating solution 1 shown in Table 7 below was applied to both sides of the longitudinally stretched film with the thickness of the functional layer (after drying). Was applied to a tenter, and then stretched 3.8 times at 120 ° C. in the transverse direction, followed by heat treatment at 235 ° C. for 10 seconds, relaxed 10% in the transverse direction, and 6 μm ( A laminated white film having a thickness of 74 μm was obtained with a thickness of (surface layer) / 62 μm (intermediate layer) / 6 μm (surface layer).
When the obtained laminated white film was evaluated, the image quality suitability, the characters, the image peeling / removal suitability, the print transportability, the writing property, and the functional layer appearance were all good. The characteristics of this film are shown in Tables 4 and 8 below.

[Examples 1-2 to 1-4]
A laminated white film was obtained in the same manner as in Example 1-1 except that the thickness of the functional layer (after drying) was changed as shown in Table 1.
As shown in Tables 4 and 8 below, the obtained laminated white film had good image quality and good writing properties.

[Examples 1-5 to 1-14]
A laminated white film was obtained in the same manner as in Example 1-1 except that the composition of the functional layer was changed. The production conditions in each example are shown in Table 1 below, and the coating solution composition of the functional layer is shown in Table 7 below.
As shown in Tables 4 and 8 below, the obtained polyester film had good image quality and good writing properties.

[Example 1-15]
40 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.63 dl / g, 15 parts by weight of a crystalline polypropylene homopolymer chip having a melt flow index of 7 ml / 10 minutes, and ears and masters produced during the production of the polyester of Example 1-1 A laminated white film having a thickness of 75 μm was obtained in the same manner as in Example 1-1, except that the mixed raw material obtained by mixing the recycled product from the roll ear portion at a ratio of 45% by weight was used as the intermediate layer. The thickness of each layer of the obtained film was 6 μm / 63 μm / 6 μm. The total amount of polypropylene derived from the crystalline polypropylene homopolymer chip and the recycled product in the intermediate layer is 24% by weight.
When the obtained laminated white film was evaluated, the image quality appropriateness, characters, image peeling / removal appropriateness, print transportability, writing property, and functional layer appearance were all good. The characteristics of this film are shown in Tables 4 and 8 below.

[Examples 1-16 to 1-18]
A laminated white film was obtained in the same manner as in Example 1-15 except that the functional layer thickness (after drying) was changed as shown in Table 1. As shown in Tables 4 and 8 below, the obtained laminated white film had good image quality and good writing properties.

[Examples 1-19 to 1-27]
A laminated white film was obtained in the same manner as in Example 1-15 except that the composition of the functional layer was changed. The production conditions in each example are shown in Table 1 below, and the coating solution composition of the functional layer is shown in Table 7 below.
As shown in Tables 4 and 8 below, the obtained polyester film was good in image quality suitability, character, image peeling / removal suitability, print transportability, and writing property.

[Example 1-28]
3 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g, 10 parts by weight of a crystalline polypropylene homopolymer chip having a melt flow index of 10 ml / 10 minutes, and ears and masters produced during the production of the polyester of Example 1-1 A laminated white film having a thickness of 75 μm was obtained in the same manner as in Example 1-1 except that the mixed material obtained by mixing the recycled product from the roll ear part at a ratio of 87% by weight was used as the intermediate layer. The thickness of each layer of the obtained film was 6 μm / 63 μm / 6 μm.
When the obtained laminated white film was evaluated, the characters, image peeling / removal appropriateness, print conveyance property, writing property, and functional layer appearance were all good. The characteristics of this film are shown in Tables 4 and 8 below.

[Examples 1-29 to 1-31]
A laminated white film was obtained in the same manner as in Example 1-28 except that the functional layer thickness (after drying) was changed as shown in Table 1. As shown in Tables 4 and 8 below, the obtained laminated white film had good image quality and good writing properties.

[Examples 1-32 to 1-40]
A laminated white film was obtained in the same manner as in Example 1-28, except that the composition of the functional layer was changed. The production conditions in each example are shown in Table 1 below, and the coating solution composition of the functional layer is shown in Table 7 below.
As shown in Tables 4 and 8 below, the obtained polyester film had good characters, proper image peeling and removal, printing transportability, and writing properties.

[Example 1-41]
A crystalline polypropylene homopolymer chip containing 15% by weight of a polyethylene terephthalate chip containing 50% by weight of titanium oxide particles having an average particle diameter of 0.32 μm and an intrinsic viscosity of 0.65 dl / g, and a melt flow index of 8 ml / 10 min. 3 parts by weight, 1.6 parts by weight of polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g, containing 0.5% by weight of silica particles having an average particle size of 4.1 μm, and polyethylene having an intrinsic viscosity of 0.68 dl / g A laminated white film having a thickness of 75 μm was obtained in the same manner as in Example 1-15 except that 82.1 parts by weight of the terephthalate chip was used as the surface layer. The thickness of each layer of the obtained film was 6 μm / 63 μm / 6 μm.
When the obtained laminated white film was evaluated, the image quality suitability, the characters, the image peeling / removal suitability, the print transportability, and the functional layer appearance were all good. The characteristics of this film are shown in Tables 5 and 9 below.

[Examples 1-42 to 1-44]
A laminated white film was obtained in the same manner as in Example 1-41 except that the thickness of the functional layer (after drying) was changed as shown in Table 2. The obtained laminated white film had good image quality and good writing properties as shown in Tables 5 and 9 below.

[Examples 1-45 to 1-53]
A laminated white film was obtained in the same manner as in Example 1-41 except that the composition of the functional layer was changed. The production conditions in each Example are shown in Table 2 below, and the coating solution composition of the functional layer is shown in Table 7 below.
As shown in Tables 5 and 9 below, the obtained polyester film had good image quality, characters, image peeling / removal suitability, and print transportability.

[Example 1-54]
A crystalline polypropylene homopolymer chip containing 15% by weight of a polyethylene terephthalate chip containing 50% by weight of titanium oxide particles having an average particle size of 0.32 μm and an intrinsic viscosity of 0.65 dl / g, and a melt flow index of 8 ml / 10 min. 5 parts by weight, 10 parts by weight of polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g containing 3.5% by weight of silica particles having an average particle diameter of 4.1 μm, and a polyethylene terephthalate chip having an intrinsic viscosity of 0.68 dl / g A laminated white film having a thickness of 75 μm was obtained in the same manner as in Example 1-15 except that 74.5 parts by weight was used as the surface layer and the coating solution was applied only on one side in the coating process after longitudinal stretching. The thickness of each layer of the obtained film was 6 μm / 63 μm / 6 μm.
With respect to the obtained laminated white film, evaluation of image quality appropriateness, character, image peeling / removal appropriateness, and writing property was performed on the surface where the coating liquid was not applied. Appropriate image quality, print transportability and functional layer appearance were good. The characteristics of this film are shown in Tables 5 and 9 below.

[Example 1-55]
15 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g containing 50% by weight of titanium oxide particles having an average particle diameter of 0.12 μm, and 15 parts by weight of a crystalline polypropylene homopolymer chip having a melt flow index of 8 ml / 10 minutes 10 parts by weight of polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g containing 3.5% by weight of silica particles having an average particle diameter of 4.1 μm and 60 weight of polyethylene terephthalate chip having an intrinsic viscosity of 0.69 dl / g A laminated white film having a thickness of 75 μm was obtained in the same manner as in Example 1-15 except that the content of The thickness of each layer of the obtained film was 6 μm / 63 μm / 6 μm.
When the obtained laminated white film was evaluated, characters and image peeling and removal were appropriate, and print transportability, writing property, and functional layer appearance were all good. The characteristics of this film are shown in Tables 5 and 9 below.

[Examples 1-56 to 1-58]
A laminated white film was obtained in the same manner as in Example 1-55 except that the functional layer thickness (after drying) was changed as shown in Table 2.
The obtained laminated white film had good image quality and good writing properties as shown in Tables 5 and 9 below.

[Examples 1-59 to 1-67]
A laminated white film was obtained in the same manner as in Example 1-55 except that the composition of the functional layer was changed. The production conditions in each Example are shown in Table 2 below, and the coating solution composition of the functional layer is shown in Table 7 below.
As shown in Tables 5 and 9 below, the obtained polyester film was suitable for character and image peeling removal, and had good print transportability and writing property.

[Example 1-68]
15 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g, containing 50% by weight of titanium oxide particles having an average particle size of 0.32 μm, and 15 parts by weight of a crystalline polypropylene homopolymer chip having a melt flow index of 8 ml / 10 minutes Example 1-15, except that 70 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g containing 5.0% by weight of silica particles having an average particle diameter of 11.1 μm was used as the surface layer. Thus, a laminated white film having a thickness of 75 μm was obtained. The thickness of each layer of the obtained film was 6 μm / 63 μm / 6 μm.
When the obtained laminated white film was evaluated, the image quality suitability, print transportability, writing property and functional layer appearance were all good. The characteristics of this film are shown in Tables 5 and 9 below.

[Example 1-69]
A laminated white film having a thickness of 75 μm and a thickness of each layer of 6 μm / 63 μm / 6 μm in the same manner as in Example 1-15, except that the heat treatment temperature in the film forming step was 201 ° C. for 10 seconds. Got.
When the obtained laminated white film was evaluated, the print transportability, writing property, and functional layer appearance were all good. The characteristics of this film are shown in Tables 5 and 9 below.

[Comparative Example 1-1]
A polyester film was obtained in the same manner as in Example 1-1 except that in Example 1-1, a polyethylene terephthalate chip was used instead of the crystalline polypropylene homopolymer chip and no functional layer was provided. As shown in Tables 6 and 10, the obtained polyester film had poor image quality, character, image peeling / removal suitability, print transportability, and writing property.

[Comparative Example 1-2]
A laminated white film was obtained in the same manner as in Example 1-1 except that the composition of the functional layer was changed. The production conditions of Comparative Example 1-2 are shown in Table 3 below, and the coating solution composition of the functional layer is shown in Table 7 below.
As shown in Tables 6 and 10 below, the obtained polyester film was poor in image quality suitability and print transportability.

[Example 2 group]
As examples of the second embodiment, examples 2-1 to 2-6 and comparative examples 2-1 to 2-2 will be described.

[Example 2-1]
As an intermediate layer, a mixed raw material obtained by mixing 80 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.67 dl / g and 20 parts by weight of a crystalline polypropylene homopolymer chip having a melt flow index of 10 ml / 10 minutes is 280 ° C. Was sent to the main vented twin screw extruder.
As a surface layer, crystalline polypropylene containing 15% by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g, containing 50% by weight of titanium oxide particles having an average particle diameter of 0.32 μm, and a melt flow index of 8 ml / 10 min. 15 parts by weight of a homopolymer chip, 3.5 parts by weight of silica particles having an average particle diameter of 4.1 μm, 10 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g, and an intrinsic viscosity of 0.69 dl / g A mixed raw material obtained by mixing 60 g by weight of polyethylene terephthalate chip was fed into a sub-vented twin screw extruder set at 280 ° C.
Through a gear pump and a filter, the polymer from the main extruder is an intermediate layer, and the polymer from the sub-extruder is the surface layer. The two layers and three layers (surface layer / intermediate layer / surface layer) are co-extruded from the die. Extrusion and rapid cooling and solidification on a cooling roll whose surface temperature was set to 30 ° C. using an electrostatic application adhesion method, to obtain an unstretched sheet having a thickness of 887 μm.
The obtained unstretched sheet was stretched 3.1 times at 92 ° C. in the machine direction, guided to a tenter, and then stretched 3.8 times at 120 ° C. in the transverse direction, and then heat treated at 235 ° C. for 10 seconds. A biaxially oriented laminated white polyester film having a thickness of 6 μm (surface layer) / 62 μm (intermediate layer) / 6 μm (surface layer) and a total thickness of 74 μm was obtained by relaxing 10% in the lateral direction.
When the obtained laminated white polyester film was evaluated, the image quality suitability, characters, image peeling removal suitability, and writing property were all good. The characteristics of this film are shown in Tables 12 and 13 below.

[Example 2-2]
As an intermediate layer, 40 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.63 dl / g, 15 parts by weight of a crystalline polypropylene homopolymer chip having a melt flow index of 7 ml / 10 min, and the polyester of Example 2-1 were produced. A biaxially oriented laminated white polyester film having a thickness of 75 μm in the same manner as in Example 2-1, except that a mixed raw material obtained by mixing 45% by weight of the regenerated product from the generated ear part or master roll ear part was used. Got. The thickness of each layer of the obtained film was 6 μm / 63 μm / 6 μm. The total amount of the polypropylene derived from the crystalline polypropylene homopolymer chip and the recycled product in the intermediate layer was 24% by weight.
When the obtained laminated white polyester film was evaluated, the image quality suitability, characters, image peeling removal suitability, and writing property were all good. The characteristics of this film are shown in Tables 12 and 13 below.

[Example 2-3]
As an intermediate layer, 3 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g, 10 parts by weight of a crystalline polypropylene homopolymer chip having a melt flow index of 10 ml / 10 min, and when producing the polyester of Example 2-1. A biaxially oriented laminated white polyester film having a thickness of 75 μm in the same manner as in Example 2-1, except that a mixed raw material obtained by mixing 87% by weight of the regenerated product from the generated ear part or master roll ear part was used. Got. The thickness of each layer of the obtained film was 6 μm / 63 μm / 6 μm.
When the obtained laminated white polyester film was evaluated, the characters, the image peeling / removal suitability, and the writing property were all good. The characteristics of this film are shown in Tables 12 and 13 below.

[Example 2-4]
As a surface layer, a crystalline polypropylene homopolymer having 15 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g and containing 50% by weight of titanium oxide particles having an average particle diameter of 0.12 μm and a melt flow index of 8 ml / 10 min. 15 parts by weight of a chip, 3.5 parts by weight of silica particles having an average particle size of 4.1 μm, 10 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g, and polyethylene terephthalate having an intrinsic viscosity of 0.69 dl / g A biaxially oriented laminated white polyester film having a thickness of 75 μm was obtained in the same manner as in Example 2-1, except that a mixed raw material mixed at a ratio of 60 parts by weight of the chip was used. The thickness of each layer of the obtained film was 6 μm / 63 μm / 6 μm.
When the obtained laminated white polyester film was evaluated, the characters, the image peeling / removal suitability, and the writing property were all good. The characteristics of this film are shown in Tables 12 and 13 below.

[Example 2-5]
As a surface layer, a crystalline polypropylene homopolymer containing 15 parts by weight of a polyethylene terephthalate chip having an average viscosity of 0.66 dl / g containing 50% by weight of titanium oxide particles having an average particle diameter of 0.32 μm and a melt flow index of 8 ml / 10 min. 1.3 parts by weight of polymer chips, 0.5 parts by weight of silica particles having an average particle diameter of 4.1 μm and 1.6 parts by weight of polyethylene terephthalate chips having an intrinsic viscosity of 0.66 dl / g and an intrinsic viscosity of 0 A biaxially oriented laminated white polyester film having a thickness of 74 μm was obtained in the same manner as in Example 2-2 except that a mixed raw material in which polyethylene terephthalate chips of .69 dl / g were mixed at a ratio of 82.1 parts by weight was used. . The thickness of each layer of the obtained film was 6 μm / 62 μm / 6 μm.
When the obtained laminated white polyester film was evaluated, the image quality suitability was good. The characteristics of this film are shown in Tables 12 and 13 below.

[Example 2-6]
As a surface layer, a crystalline polypropylene homopolymer containing 15 parts by weight of a polyethylene terephthalate chip having an average viscosity of 0.62 dl / g containing 50% by weight of titanium oxide particles having an average particle diameter of 0.32 μm and a melt flow index of 8 ml / 10 min. 0.5 parts by weight of polymer chips, 3.5 parts by weight of silica particles having an average particle size of 4.1 μm, 10 parts by weight of polyethylene terephthalate chips having an intrinsic viscosity of 0.66 dl / g and an intrinsic viscosity of 0.68 dl A biaxially oriented laminated white polyester film having a thickness of 75 μm was obtained in the same manner as in Example 2-2, except that a mixed raw material in which 74.5 parts by weight of a polyethylene terephthalate chip / g was mixed was used. The thickness of each layer of the obtained film was 6 μm / 63 μm / 6 μm.
When the obtained laminated white polyester film was evaluated, the image quality suitability was good. The characteristics of this film are shown in Tables 12 and 13 below.

[Comparative Example 2-1]
As a surface layer, a crystalline polypropylene homopolymer having 15 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g and containing 50% by weight of titanium oxide particles having an average particle diameter of 0.32 μm and a melt flow index of 8 ml / 10 min. Other than using a mixed raw material mixed at a ratio of 15 parts by weight of a chip and 70 parts by weight of a polyethylene terephthalate chip having an intrinsic viscosity of 0.66 dl / g and containing 5.0% by weight of silica particles having an average particle size of 11.1 μm In the same manner as in Example 2-2, a biaxially oriented laminated white polyester film having a thickness of 75 μm was obtained. The thickness of each layer of the obtained film was 6 μm / 63 μm / 6 μm.
As shown in Tables 12 and 13 below, the obtained laminated white polyester film was poor in character and image peeling / removal suitability.

[Comparative Example 2-2]
Biaxial orientation with a thickness of 75 μm and a thickness of each layer of 6 μm / 63 μm / 6 μm in the same manner as in Example 2-2, except that the heat treatment temperature in the film forming step was 201 ° C. for 10 seconds. A laminated white polyester film was obtained.
As shown in Tables 12 and 13 below, the obtained laminated white polyester film was poor in image quality suitability and character and image peeling removal suitability.

Claims

It has a functional layer containing an antistatic agent on at least one surface of a polyester film having an apparent density of 0.7 to 1.3 g / cm 3 and a thickness of 10 to 1000 μm. A laminated white film comprising a polymer incompatible with polyester.
The laminated white film according to claim 1, wherein the functional layer contains a release agent in addition to the antistatic agent.
3. The laminated white film according to claim 2, wherein the functional layer contains the release agent in a proportion of 3% by weight or more in the functional layer.
The laminated white film according to any one of claims 1 to 3, wherein the functional layer contains a crosslinked structure derived from a crosslinking agent.
The laminated white film according to any one of claims 1 to 4, wherein the functional layer is a recording layer.
6. The laminated white film according to claim 1, wherein the polyester film contains metal compound particles.
The laminated white film according to claim 6, wherein the polyester film includes silica particles, organic particles, or both as particles other than the metal compound particles.
The polyester film has both surface layers and an intermediate layer,
The both surface layers are made of polyester, a polymer incompatible with the polyester, metal compound particles, and a resin composition containing silica particles, organic particles, or both, and the arithmetic average roughness (Ra) of the surface layers. The laminated white film according to any one of claims 1 to 7, wherein is a 950 nm or less.
The laminated white film according to any one of claims 1 to 8, wherein the polyester film is a stretched film.
10. The laminated white film according to claim 1, wherein the polyester film has a content of a polymer incompatible with the polyester of 1% by weight to 70% by weight.
11. The laminated white film according to claim 6, wherein the average particle diameter of the metal compound particles is 0.05 μm or more and 0.50 μm or less.
12. The laminated white film according to claim 6, wherein the content of the metal compound particles in the polyester film is 1% by weight to 30% by weight.
The laminated white film according to any one of claims 7 to 12, wherein an average particle diameter of the silica particles or the organic particles is larger than 0.50 µm and not larger than 15.0 µm.
14. The laminated white film according to claim 6, wherein the content of the silica particles or organic particles in the polyester film is 0.005 wt% or more and 5 wt% or less.
A laminated white film having an image forming substance on a functional layer of the laminated white film according to any one of claims 1 to 14.
A recording material having an image forming substance on a functional layer of the laminated white film according to any one of claims 1 to 14.
The laminated white film or recording material according to claim 15 or 16, comprising a resin layer on the image forming substance or the functional layer.
The laminated white film or recording material according to claim 17, wherein the resin layer is laminated so as to be peelable from the image forming substance or the functional layer.