JPH0645273B2 - High-sensitivity and heat-sensitive stencil film and base paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Use) The present invention relates to a heat-sensitive stencil film and base paper suitable for preparing a stencil master by a thermal head, and more specifically to JP-A-62-282983. A thin layer consisting mainly of specific silicone oil is provided on the surface of the high-sensitivity, heat-sensitive perforated film to prevent heat fusion with the thermal head during plate making and improve the resolution of the obtained print. High-sensitivity and heat-sensitive stencil film and base paper.

(Prior Art) A method of using a thermal head to prepare a stencil plate (hereinafter abbreviated as TH method) is already known (Japanese Patent Laid-Open No. 55-1).
No. 03957, etc.), and recently, a plate-making printing apparatus in which a plate-making portion using a thermal head and a printing machine are integrated is commercially available. The heat-sensitive stencil sheet used in this printing apparatus is a laminate of a crystallized polyester film of about 2 μm and a porous support such as ultra-thin Japanese paper. However, these base papers are first perforated plate making (flash method) under flash conditions in high energy range such as infrared rays or xenon flash light.
Have been put to practical use as a film of the group described below, and these are insufficient in perforation with a thermal head having a lower energy than those used in commercially available products such as Facsimili and commercially available word processors. Therefore, it is the current situation that a thermal head with specially added energy is used.

Further, at the time of plate making, the surface temperature of the thermal head usually reaches 300 to 500 ° C. within a few milliseconds, and as a result, the head and the mere film almost instantly cause a thermal fusion (stick) phenomenon. In this case, unlike the flash method, even if heat fusion occurs even in a small portion of the head heating element, the head (heating portion) and the film are constantly moving relative to each other, so that the film around the perforated portion is There are serious problems such as tearing, peeling and fluffing. Therefore, a number of patent applications have been filed as a method for preventing sticking. Those coated with an aliphatic metal salt (JP-A-60-19592) and those provided with an overcoat layer of a phosphate ester type surfactant (JP-A-61-10229).
No. 5, etc.), those provided with an overcoat layer of a nonionic surfactant (JP-A-61-125897), those provided with a silicone release solid layer (JP-A-60-97891, etc.), A plate-making machine provided with a means for applying a fluid lubricant such as silicone oil (JP-A-60-154068).
JP-A-63-30295) (comparison described later) and the like.

(Problems to be Solved by the Invention) Currently, the printed matter produced by the commercially available heat-sensitive stencil printing system is inferior in terms of sharpness (particularly black solid portion) to the printed matter produced by the electrostatic copying (PPC) method. It is clear that the cause of this is a problem on the printing base paper side rather than the printing system. One of the problems is normal low energy TH
There is no high-sensitivity film that can be sufficiently perforated even by the method, and the other is that the thermal head becomes high in temperature during plate making (perforation), causing a sticking phenomenon and lowering the resolution.

The film proposed in JP-A-62-282983 is the most effective as a high-sensitivity film that can be sufficiently perforated by the TH method.

However, since the film has high sensitivity, when the plate is made with a high output (high energy range) thermal head used in a conventional stencil system, the occurrence of a stick is particularly remarkable. It is difficult to obtain satisfactory results with the conventional anti-sticking method, especially in the high energy range.

(Means for Solving Problems) The present inventors have found that the thermal head having a surface layer made of various materials in all ranges from a high energy region to a low energy region does not cause a stick and is sufficiently effective. I found a film that can be perforated.

That is, the present invention relates to a heat-sensitive stencil film produced by a thermal head, wherein the thermoplastic resin constituting the film has a crystallinity of 15% from a substantially amorphous level.
The stretched film has a thickness of 0.5 to 15 μm and is made of a thermoplastic resin having a melt viscosity temperature coefficient (ΔT / ΔlogVI) of 100 or less. Rate (X%) and heat shrinkage stress at 100 ° C. (Yg / mm ² ) are respectively the following formulas: 15 ≦ X
Within the range of ≦ 80, 75 ≦ Y ≦ 500, and the relationship between them is within the range of −8X + 400 ≦ Y ≦ −10X + 1,000, the viscosity at 25 ° C. on one surface of the film to be contacted with the thermal head. Is 10,000 to 50,000
A high-sensitivity and heat-sensitive stencil film comprising a thin layer mainly composed of 0CS of at least one silicone oil per unit area (m ² ) and a thermoplastic resin constituting the film are provided. The heat shrinkage rate (X) at 100 ° C. which is made of a thermoplastic resin having a temperature coefficient of melt viscosity (ΔT / ΔlogVI) of 100 or less in a range of substantially amorphous level to 15% of crystallinity (X %), 100 ° C
Heat shrinkage stress (Yg / mm ² ) at
≦ X ≦ 80, 75 ≦ Y ≦ 500, and the relationship between them is −8X + 400 ≦ Y ≦ −10X + 1,00.
In the range of 0, a stretched film having a thickness of 0.5 to 15 μm and a printing ink can be permeated, and a porous support which does not substantially deteriorate under the heating conditions at the time of perforation of the film is laminated. And a thin layer mainly composed of at least one silicone oil having a viscosity of 10,000 to 50,000 CS at 25 ° C. is provided on the non-contact surface of the film in an amount of 0.05 to 1 g per unit area (m ² ). It is a high-sensitivity, heat-sensitive stencil sheet characterized by It is necessary that the thermoplastic resin in the state of constituting the film has a substantially amorphous level to a crystallinity of 15%, and preferably the thermoplastic resin is mainly a copolyester. And the film is at a substantially amorphous level.

As a result of the present inventors conducting research on a thermoplastic film suitable for plate making by a thermal head, the following important points are obtained particularly for a high-sensitivity film for low-energy plate making (hereinafter abbreviated as high-sensitivity film). It turned out to be.

In order to use the thermoplastic resin film for high-sensitivity and heat-sensitive stencil use, the stretching process of the film is indispensable, and first, its low temperature shrinkage property is an important point. It was further found that the larger the property, the better the perforation property (perforation sensitivity) in the low energy region.

As the thermoplastic resin that constitutes the high-sensitivity film, the melt viscosity (V
I) has a large temperature dependence, that is, the temperature coefficient ΔT /
It has been found that it is necessary for the ΔlogVI value to be small.
This is one of the reasons for obtaining a stencil having a high resolution (sharpness at the hole end portion; especially, prevention of hole expansion).
It is considered that the reason is that the part that has been melted and softened by heating contracts in a form that exactly corresponds to the heated part and immediately after the flow opening, the end of the hole must be cooled and solidified, etc. . The second reason is that in order to stably pierce in a wide range of temperature that slightly changes with time in a very short time, the sharp flow characteristics as described above are necessary, and it is also necessary for the piercing sensitivity. It is thought to have an influence.

Based on the above findings, the film used in the present invention is not limited to the type of thermoplastic resin, and the above-mentioned melt viscosity conditions,
It has been found that it is necessary to satisfy the heat shrinkage characteristics (specifically, the shrinkage rate and shrinkage stress at 100 ° C).

Regarding the temperature coefficient of the melt viscosity of the thermoplastic resin used in the high-sensitivity film of the present invention, the shear rate is 6.08.
Log value of melt viscosity VI (poise) of resin under the condition of sec ^-1 ;
Temperature change Δ until logVI changes from 4.0 to 5.0
T / Δlog VI (° C.), which in the present invention is 100 or less, preferably 80 or less, more preferably 70 or less, particularly preferably 60 or less, and most preferably 50 or less ( When expressed as a coefficient, the unit is omitted.) When it is 100 or more, it is limited by fluidity required for perforation, sharp perforation, or processability into a film. Further, the preferred lower limit is such that the processability into a film is not impaired, and the strength is practically a range that can withstand lamination, perforation, and printing, and a range in which so-called low polymerization below is not included is not included. To do. The lower limit is preferably 3. Further, it is more preferably 5 or more, still more preferably 10 or more.

In addition, the temperature range that gives logVI = 5.0 (the present inventors have found that the oriented polymer has a viscosity that substantially starts flowing at the time of perforation) under the above conditions is 90 to 300.
It is necessary to be within the range of ℃, preferably 120
-280 degreeC, More preferably, it is 150-270 degreeC. Specifically, it was measured by the method described below. Needless to say, the thermoplastic resin used in the film of the present invention must be one that can give the film shrinkage characteristics described below, and excluding those having extremely poor film moldability and film strength. The melt viscosity characteristics of the above resin are
Basically, it is the original property of the resin, but it is modified within the range that does not adversely affect the perforation properties and other practical properties, that is, after mixing with other resins and other additives, plasticizers, oligomers, etc., or reacting with them. It does not matter even if it is the value after doing.

Specifically, as a preferable thermoplastic resin as a raw material that satisfies the conditions such as the temperature gradient of the melt viscosity, first of all, in the first group, polyester resins include polyethylene terephthalate, polybutylene terephthalate, and more particularly Although not modified, polyethylene terephthalate (for example, in addition to ethylene glycol as a diol component, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neo as a copolymerization component) Pentyl glycol, polyethylene glycol, polytetramethylene glycol, cyclohexanedimethanol, those having an aromatic ring, for example, those having a bisphenol nucleus and their modified products, those having a phenol nucleus, or other known substances At least one nuclear diol or other ingredients any of the as the base 15 mol% or less, preferably those containing 10 mol% or less chosen,
Alternatively, as the dicarboxylic acid component, at least selected from terephthalic acid, other aromatic compounds such as isophthalic acid, phthalic acid, carboxylic acid having a bisphenol nucleus, and aliphatic dicarboxylic acids such as succinic acid and adipic acid. 15 mol% or less, preferably 10 mol% of one acid component or other component based on any of the above
The following are included, or those containing both of the above components at the same time (so-called a small amount by copolymerization in the modi-eye region, etc.)], and as the second group, other various copolyesters (the above or other than that). A known alcohol component or similarly an acid component, respectively, or simultaneously, 10 mol% or more, preferably 15 mol% or more, more preferably 20 mol% or more, and the upper limit thereof is 85 mol% or less, preferably 80 mol% or less. Mol% or less, more preferably 60 mol% or less, still more preferably 50 mol% or less, still more preferably 40 mol% or less, in which at least one monomer is copolymerized. Those that have been positively imparted with properties beyond). Of these, the polymer is preferably a copolymer, more preferably the latter second group of copolymers. More preferably, of these, a substantially amorphous polyester resin is more preferable. Next, a polymer or copolymer of oxyacid type as a monomer, or a copolymer of these with a polyester of the above-mentioned monomer may be used.

The substantially amorphous polyester used in the heat-sensitive perforable film of the present invention is mainly a so-called highly crystalline polyethylene terephthalate whose commercially available crystalline melting point (by DSC method) is 245 to 260 ° C. Unlike the resin described above, the substantially amorphous level means that the polymer as a raw material and a polymer composed of mixed components or a blended composition of polymers are sufficiently annealed. The crystallinity measured by the density method is 10% or less, preferably 5% or less, more preferably 5% or less, which is measured by using a sample in which the crystallinity is fixed in the equilibrium state and fixed by the X-ray method as a standard. Is the DSC method (however, 10 ° C
The melting point is hardly seen even when measured at a heating rate of 1 / min. Further, the crystallinity may be simply obtained by measuring the area of the dissolution energy measured by the DSC method for the sample whose crystallinity is clarified and measured by the sample to be measured.

The most preferred substantially amorphous polyester of the present invention is a monomer which constitutes a polymer. In detail, terephthalic acid and its isomers, their derivatives, aliphatic dicarboxylic acids, etc. are used as an acid component. One or two or more kinds of acid components selected from the derivatives and the like are used, and then, as glycol (alcohol) components, ethylene glycol, its derivatives (polyethylene glycol, etc.), alkylene glycols (trimethylene glycol, tetramethylene glycol, Hexamethylene glycol, etc.), saturated saturated cyclic glycols (cyclohexanediol, cyclohexanedimethanol, cyclohexanedialkylols, etc.) are used to polymerize using one or more glycol components. This is a substantially amorphous polymer of It be good if selected from the combinations. In addition, it is acceptable to add components other than the above as long as they are within the above range. Preferably, at least an alcohol component of both components is copolymerized,
The ratio is the same as the level of the above-mentioned copolyester. Then, the preferred combination may include terephthalic acid as the main acid component and optionally include isomers (isophthalic acid, phthalic acid) at minor (15 mol% or less) levels. In addition, a mixed component mainly composed of ethylene glycol and cyclohexanedimethanol as an alcohol component is polymerized.

More preferably, a terephthalic acid-based one similar to the above can be selected as the acid component, ethylene glycol and 1,4-cyclohexanedimethanol-based one can be selected as the alcohol component, and a large amount of the copolymerized alcohol component can be selected. The ratio of the above two components is 60 to 80 mol% of ethylene glycol and 40 to 20 mol% of 1,4-cyclohexanedimethanol, more preferably 64 to 75 mol% of the former and 36 to 25 mol% of the latter. Mol%. Most preferably, the former is 67 to 73 mol% and the latter is 33 to 2
It is 7 mol%.

The degree of polymerization of the copolymer is 3 when using an intrinsic viscosity (60/40 wt% phenol / tetrachloroethane solution).
Measured at 0 ° C.) is about 0.50 to 1.2,
It is preferably about 0.60 to 1.0. More preferably, it is about 0.60 to 0.90. However, this degree is common to both homopolymers and copolymers of the polyester in the future. When the above homopolyester or preferably the copolyester is mixed with another type of polyester, or a polymer which can be mixed other than the polyester, the ratio thereof is 50% by weight or less, preferably 40% by weight or less, more preferably Is 30% by weight or less, and may be used within a range in which the properties of the film of the present invention described above are not impaired.

Further, if desired, known specific stabilizers for heat or ultraviolet rays, lubricants, antiblocking agents, antistatic agents, pigments, dyes, etc. may be mixed with the preferred specific copolymer used in the present invention within a range that does not hinder. good.

The density of the stretched film obtained from the above polyester is different depending on the properties of the monomer used, but in the case of a polyester having a composition in which ethylene glycol used in the present invention is a major component or particularly a single component , Those that crystallize, including that, about 1200-1,345
(G / cm ³ ), preferably 1,220 to 1,3
It is about 20 (g / cm ³ ). However, this is not the case when this is mixed with another polyester or another resin, and the above values are only the values corresponding to the polymer component forming the substrate.

Further, as the above-mentioned raw material, it is more preferable that the absolute value (that is, sufficiently annealed and in equilibrium state) crystallinity of the polyester resin to be used is a group that can be satisfied as described above. Depending on the case, the thing of the thing can also be used. It was obtained under the condition that the crystallization was not sufficiently promoted even if the raw material had the absolute value above the crystallinity (that is, 10% or more) (for example, quenching and stretching at a temperature as low as possible). It is sufficient that the film itself has a crystallinity of 15% or less and is dimensionally stable and can be put to practical use. In that case, the above-mentioned limit is the value in the state of the final film.

Next, the case other than the polyester-based polymer will be described. For the nylon-based resin, so-called nylon 6, 60, 12, 6-
Other known compounds such as 10, 6-12, 6-66 and the like are preferable, and copolymers are preferable. These copolymers are binary, ternary or higher, and are ring-opening polymerized of caprolactam-based monomers, or polycondensed of dicarboxylic acid components and diamine components, Also, various copolymers such as copolymers of these are known, and these can be used. Preferred examples include, for example, a copolymer of nylon 6-66, or a copolymer of terephthalic acid having an aromatic ring and the like. Among the above-mentioned copolymers, 1 to 5 are monomers having a branched hydrocarbon component, a saturated cyclo ring, and an aromatic ring as rigid parts in the molecular structure.
0 mol%, preferably 2 to 30 mol%, more preferably 3 to 20 mol%. More preferably, those having a large amount of amorphous component and the like, which are copolymerized in an amount of about 3 to 15 mol% and have a rigid molecular structure without lowering Tg, are preferable. Tg
Is generally 20 to 150 ° C, preferably 40 to 150 ° C
And more preferably 45 to 130 ° C., further preferably 50 to 110 ° C., and most preferably 60 to 100 ° C. The crystallinity is most preferably as low as possible and close to amorphous, but the range is 30% or less, preferably 20%, more preferably 15% or less.

Other polymers include copolymers such as polyolefins, polyethylenes, acrylic acid derivatives, ethylene / vinyl alcohols, polycarbonates, etc., but the characteristic range is the same as above.

Next, the film characteristics of the present invention will be described. Good perforation with a low heat source requires, first of all, the heat shrinkage property of the film in a predetermined low temperature range.
The heat shrinkage rate and heat shrinkage stress at 00 ° C. are adopted as evaluation criteria of the low temperature shrinkage property, and the suitability range thereof is limited. The value is such that the heat shrinkage ratio X is at least 15
%, Preferably at least 20%, more preferably at least 30%, even more preferably at least 40%. The upper limit is 80% or less. The reason will be described later. The heat shrinkage stress value Y is at least 75 g / mm ² or more, preferably 100 g / mm ² or more, more preferably 15
It is 0 g / mm ² or more, and its upper limit is 500 g / mm ² or less, preferably 450 g / mm ² or less.

The details will be described below.

Heat shrinkage ratio (X%) and heat shrinkage stress (Yg / mm ² )
Both are measured values at 100 ° C.

The suitable range in the present invention is 15 ≦ X ≦ 80, 75 ≦ Y ≦ 500.
Within the range of, and the relationship between them is -8X + 400≤Y≤-10X
It is +1,000. The reasons for limiting the area will be described below.

In the region of X <15, if Y is small, the piercing property is deteriorated, and if Y is large, the hole expandability tends to be large, and in the region of Y <75, the low temperature shrinkage property of the film is mainly small and the piercing property is small. Becomes worse. Also, X ≧ 15 and Y ≧ 7
The film in the range of 5 and Y <-8X + 400 has shrinkage characteristics generally in a high temperature part depending on the draw ratio and is not perforated with a low heat source, or is perforated with a low heat source but has a dull shape. However, the holes are not perfect, or the ends of the holes do not have sherps, and dusts are likely to remain after drilling. Furthermore, a region of X> 80 and Y> 75 or Y
> 500 and X> 15 region or X ≦ 80 and Y ≦ 5
In the region of 00 and Y> -10X + 1,000, there is a tendency that the film is difficult to obtain due to poor stretching, and there is a tendency that the low heat source piercing property is good but the hole expansion tendency is large. Become.

As a more preferable shrinkage characteristic at low temperature, 80 is preferable.
If the shrinkage property at 80 ° C. is specified, the heat shrinkage at 80 ° C. is at least 10% or more, preferably 15% or more, more preferably 20% or more, further preferably 30% or more. At least 50 g / mm ² or more, preferably 100 g / mm ² or more, more preferably 150 g / mm ²
It is the above film.

Hereinafter, other necessary characteristics that the thermoplastic resin film of the present invention must satisfy will be described in order.

First, if the dimensional stability of the base paper film for this purpose is poor, curling of the base paper, peeling of the support, distortion of letters, etc. occur in practice. For example, a commercially available 7 μm vinylidene chloride-based copolymer film is heat-set (for example, 110 ° C. for 20 seconds) within a range that retains the piercing property after stretching to reduce the shrinkage rate as described above, but still When the support is used as a laminated base paper, curling of the base paper and peeling of the support occur during long-term storage at room temperature, which lowers the resolution and poses a practical problem.

However, in the case of the thermoplastic resin film constituting the film and the base paper of the present invention, the dimensional stability at room temperature is also good, and even if it is heat-treated in a hot air circulation constant temperature bath at 50 ° C. for 10 minutes, there is a substantial problem. It is necessary that such shrinkage is difficult to occur. Therefore, among the shrinkage characteristics of the film, the shrinkage initiation temperature at which the film shrinks substantially, that is, shrinks by 2 to 3% in area, preferably exceeds 50 ° C, more preferably 55 ° C.
It is preferably at least ° C, more preferably at least 60 ° C. This is a matter limited by dimensional stability, laminating workability, and hole expansion.

Next, the suitable thickness of the film according to the present invention will be described. An appropriate film thickness is 0.5 to 1.5 μm. When the porous support is laminated and used, if it is 0.5 μm or less, the processability and strength of the film are low, and if it is 15 μm or more, the perforation sensitivity is not good. The thickness is preferably 0.5 to 7 μm, more preferably 1 to 6 μm. Also, when using dot-shaped perforations that do not require a porous support, workability of the film,
From the viewpoint of operability, strength, strength of the remaining portion between dots, etc., it is about 5 to 15 μm, preferably 6 to 13 μm, more preferably about 8 to 12 μm.

The porous support used in the present invention is a single substance such as a natural fiber, a regenerated fiber, a synthetic fiber or the like which is capable of transmitting a printing ink and does not substantially undergo thermal deformation under the heating conditions where the film is perforated. A non-woven fabric, a woven fabric, or the like, which is a porous support made of a mixture of these materials as a raw material, or another porous body is used. 3 for non-woven type thin paper
It has a basis weight of 0 to ³ g / m ² , preferably 20 to 4 g / m ² , and more preferably 15 to 4 g / m ² . In the case of a woven type mesh, it is 500 to 15 mesh, preferably 300 to 50 mesh, more preferably 250 to
It is 80 mesh, and an appropriate one may be selected according to the resolution required for printing.

A particularly preferable porous support is a porous support containing mainly 0.5 to 5 denier polyester fibers.

Further, the film and the porous support are laminated by adhering or heat welding with an adhesive or the like under the condition that the perforation suitability of the film is not hindered. In this case, the adhesive is dissolved in a solvent and laminated, or various adhesives such as hot-melt type, emulsion-latex type, reaction type (thermosetting type, moisture curing type, ultraviolet curing type, electron beam curing type) powder type, etc. The agent may be laminated by a generally known method. These are preferably generally 0.1 to 8 g / m ² , more preferably 0.3 to
It is 5 g / m ² . Next, when the adhesive is a thermoplastic component, it is more preferably 0.5 to 4 g / m ² , more preferably 0.3 to ² g / m ² , and most preferably 0.3 to 1 g / m ² when it is a thermosetting or crosslinkable component. m ² .

When the film and the base paper described above are plate-made by a high-energy thermal head such as a commercially available printing machine, word processor or Facsimile, a stick will occur unless the film surface is subjected to the stick preventing treatment. The present inventors have conducted research on the perforation of the high-sensitivity film by the TH method, and as a result, it has been found that there are the following important points.

First of all, the thermal fusion in the flash method and the thermal fusion in the TH method cannot be handled in the same way. Particularly in the TH method, the film and the thermal element move relative to each other under heating, so that even a slight fusion point may cause trouble. In particular, the high-sensitivity film used in the present invention has a logVI = 5.0 range of 90 to 300 [deg.] C. as described above, and has a thermal head surface temperature of 300 to 5 during perforation.
Since the temperature reaches 00 ° C, it is easy to stay in a high temperature region (high energy region). Because it has high sensitivity characteristics,
Since a material having a large shrinkage property at a low temperature (specifically, a shrinkage rate and a shrinkage stress at 100 ° C.) and having the specific amorphous or low crystallinity is preferably used, it is easily sticky during melting, Melt-like polymer easily aggregates and hardens, which promotes sticking.

For this reason, in order to prevent even a slight fusion point, the stick prevention layer must be uniform and not particularly effective. If the layer is a solid layer, it is difficult to form a thin uniform layer that does not hinder heat transfer during perforation.

Next, similarly, since the head and the film are relatively moved, even if a uniform layer is formed, the head may be scraped by the head. Therefore, even if a large amount is formed so as to inhibit perforation, the effect of preventing stick cannot be expected in some cases.

Further, since the film used in the present invention has high sensitivity,
Even if the film has a thickness of 5 μm or more, it can be perforated by using a thermal head such as a commercially available printing machine, word processor, and fax machine. In particular, when a film having a thickness of 5 to 15 μm, preferably 6 to 13 μm, more preferably 8 to 12 μm is used for the dot-like perforation which does not require a porous support, a clear printed matter can be obtained if no sticking occurs. It is particularly sensitive to stakes because it does not use the body. It has also been found that the thicker the film thickness, the stronger the anti-sticking method must be. Further, when a porous support mainly composed of polyester fiber having a denier of 0.5 to 3 is used as the porous support, a clear printed matter can be obtained as in the case where no support is generated, as in the case where the support is not required. However, since the support is not stiff, when the sticking occurs, problems such as jamming of the base paper in the plate making machine, image distortion, and peeling of the film occur. It goes without saying that special caution is required when using a high-sensitivity film.

Based on the above findings, as a result of earnest research, the present invention has reached the stick prevention method. That is, in the present invention,
Viscosity at 25 ° C is 10,000-50,000CS for high-sensitivity film that can be used under wide perforation conditions as described above.
(Centistokes) is to provide a layer mainly composed of at least one silicone oil specified.

The silicone oil used in the present invention is dimethyl silicone oil which is liquid at room temperature, and ether-modified silicone oil, higher fatty acid-modified silicone oil,
It is another known modified silicone oil, and its viscosity is a value based on JIS K2283 and needs to be 10,000 to 50,000 CS at 25 ° C. This preferred range is 10,000 to 20,000 CS.

JP-A-63-30295 discloses a method of applying silicone oil in the plate-making machine as a method for using it in the anti-stick layer. In a roll-shaped heat-sensitive stencil paper in which the base paper is wound in a roll, if a liquid release agent is used at room temperature, these release agents will become a support (Japanese paper) when wound.
It is described that it is difficult to transfer to the side and maintain a constant coating amount over time.

However, as described above, in the case of a high-sensitivity film, it is necessary to limit it to a specific silicone oil that is unlikely to be rubbed because it is highly apt to stick under high energy. In the above-mentioned known technology, the silicone oil having a viscosity in the range of 2 to 5,000 CS is shown in the examples.
Application of silicone oils over 5,000 CS has been shown to be difficult. Further, the combination with the film is different from that of the present invention. When the base paper is preliminarily treated, a silicone oil having a high viscosity (5,000 CS or more) or a solvent can be used, and a uniform layer can be formed by the method described later.

The lower limit viscosity of the silicone oil used in the high-sensitivity film of the present invention is 10,000 CS. If it is less than 10,000 CS, it is liable to be scraped off mainly by the thermal head during plate making, and when the high-sensitivity film of the present invention is used, the effect of preventing sticking is not sufficient. Further, in the case of the roll-shaped heat-sensitive stencil sheet as described above, the effect of sticking is reduced by "transfer". In the case of roll-shaped heat-sensitive stencil paper,
It is also necessary to consider winding misalignment. The upper limit of the viscosity is 50,000
CS is 50,000 CS or more, and although the amount scraped by the thermal head at the time of plate making seems to be small, an effect that the stick preventing effect is not so good is obtained. Further, when the viscosity is high, the perforation sensitivity tends to be lowered due to the above reason. It is considered that this is due to the characteristics of the polymer itself constituting the film (melt viscosity characteristics depending on molecular weight or molecular structure such as functional groups). Further, when silicone oil having a high viscosity is used, slippage with a machine tends to become worse in a plate making machine, which may cause troubles such as paper jamming during transportation.

Next, in the present invention, the thin layer is mainly composed of a specific silicone oil, and the silicone oil needs to be 50% by weight or more, preferably 70% by weight or more.
If it is less than 50% by weight, it is difficult for silicone oil to form a uniform film-like layer, and a sufficient effect cannot be obtained.

As other components to be mixed in this layer, those which do not inhibit the sticking prevention effect of the silicone oil are selected, and more preferably those which promote the effect. These include, for example, silica as solid fine particles (5 μm or less),
There are carbon, graphite, molybdenum compounds, inorganic substances such as mica, and fine particles (5 μm or less) such as fatty acids, fatty acid esters, fatty acid amides, and fats. Also,
You may add an antistatic agent and the substance which improves heat conductivity.

The thin layer is generally about 0.05 to 1 g / m ² per unit area (m ² ). Although it depends on the substance constituting the thin layer, it is preferably 0.05 to 0.75 g / m ² , and more preferably 0.05 to 0.5 g.
/ m ² . The lower limit of the thin layer amount is the limit at which the sticking prevention effect is exhibited or the transfer transfer limit, and the upper limit is the limit at which troubles such as clogging of the base paper do not occur in the plate making machine.

Examples of the method for forming the thin layer include coating, spraying, kneading into a polymer constituting the film, and transferring from another layer by a coextrusion method.

Each property described in the present invention was evaluated by the following methods.

(1) Temperature coefficient of melt viscosity Capillograph manufactured by Toyo Seiki Co., Ltd. (capillary fluidity tester, capillary diameter 1.0 mm, length 10.0 mm (type E
Shape)) and change the heating temperature by 10 ° C pitch,
The melt viscosity "VI (poise)" at each temperature was calculated using a shear rate of 6.08s.
Measured under the condition of ec ^-1 (extrusion rate 0.5 mm / min), and graph the relationship between logarithmic value of melt viscosity (log VI) and heating temperature.
From the graph, the temperature difference required for the log VI value to change from 5.0 to 4.0 was read as the temperature coefficient of melt viscosity.

(2) Heat shrinkage rate A 50 mm square film sample was left for 10 minutes in a hot air circulation thermostat set at a predetermined temperature (80 ° C or 100 ° C) in a freely shrinkable state, and then the amount of shrinkage of the film was calculated. , Expressed as a percentage of the value divided by the original size, and the average value in the vertical and horizontal directions was adopted. (Similar values at 50 ° C were also used for dimensional stability evaluation.) (3) Heat shrinkage stress The film was sampled into a strip type with a width of 10 mm, and it was set to 50 mm between the chucks with strain gauges.
Immerse it in silicone oil heated to each temperature,
It was obtained by detecting the stress generated. When the silicone oil temperature was 100 ° C. or lower, the value 10 seconds after the immersion was used.

(4) Density Generally, the crystallinity of polyethylene terephthalate varies depending on the processing conditions, and the density at 25 ° C (9 g / cm ³ )
Relation between crystallinity and crystallinity (Xc, 0 ≦ Xc ≦ 0.6): 9 = 1.47X
c + 1.331 (1-Xc) is known, and it was calculated by substituting the measured density. The film density here is JIS
According to K-7112, the density gradient tube method was used to measure the temperature at 23 ° C., and the temperature was converted into the above equation.

(Examples) The present invention is further described below with reference to examples, but the invention is not limited thereto.

Examples and Comparative Examples Substantially amorphous copolyester (Eastman
KODAR made by Kodak Company DETG6763, ΔT / Δlog VI = 4
0) is extruded with a T-die to form a sheet, and the sheet is
Stretcher at 90 ℃, 3.5 × 3.5 times in biaxial direction
The film was stretched to obtain 2 μm (film A). Of the film
Shrinkage at 100 ℃ is 63% and 65%, respectively.
Compressive stress is 180g / mm²And 200 g / mm²It was.

Next, a copolymerized polyester using 75 mol% of terephthalic acid and 25 mol% of isophthalic acid as acid components and 50 mol% of 1,4-butanediol and 50 mol% of ethylene glycol as alcohol components (mp 185 ° C., ΔT / Δ
logVI = 10), 70 mol% of terephthalic acid, 10 mol% of isophthalic acid, 15 mol% of adipic acid, 5 mol% of succinic acid, 30 mol% of 1,4-butanediol as an alcohol component, and 70 mol of ethylene glycol. % Of copolymerized polyester (mp 133 ° C, ΔT / ΔlogV
I = 7) and 90 mol% phthalic acid, 1 isophthalic acid
0 mol%, ethylene glycol 8 as alcohol component
Copolyester using 0 mol% and 10 mol% of 1,4-butanediol (mp 158 ° C., ΔT / Δlog VI
= 15) was formed into a sheet in the same manner as described above, and stretched in a biaxial direction at 85 ° C. by 3.0 × 3.0 times to obtain a stretched film of about 4 μm (films C, D and E). The crystallinity of each film is 10% or less, and the shrinkage rate of each film at 100 ° C. is 67%.
%, 62%, 77%, and the shrinkage stress at the same temperature was 220 g / mm ² , 190 g / mm ² , 225 g / mm ² .

Each film was laminated with a thin paper (manufactured by a wet method) mainly composed of polyester fiber weighing 11 g / m ² using a methanol solution of vinyl acetate adhesive, and the solution shown in Table 1 was applied to the non-bonded surface of each film. It was applied to obtain a heat-sensitive stencil sheet.

Each base paper was evaluated by the following method.

(1) Effect of preventing stickiness and evaluation of printed matter Each of the base papers treated as described above is used as a personal word processor, Wordboy PW-70 (manufactured by Canon Inc., 32
Printing speed of 8.5 with a printing matrix of x32 dots
(For characters / second), select the printing density level "Dark (maximum printing energy)" for plate making (the maximum value of the thermal head surface temperature at that time is about 500 ° C), and then press the lithographic printing machine Lithograph AP7200 (ideal science). Printed by Kogyo Co., Ltd.). As a print pattern, special symbols including numbers, hiragana, kanji, and solid parts (10.5 point JIS size printing) 12
It is composed of 6 symbols, and the number of symbols in the state in which a stick is generated and the holes are widened or the film is torn out of the total number of symbols and the black portion of the ink is spread beyond the size of the symbol by printing, Of less than 5% is designated as a passing line and 5 to 20% is designated as Δ (the following is rejected), 20 to 80
%, X was 80% or more, and particularly when film tearing occurred, it was indicated as xx. Also, if the printed matter is clear (○ is the clearest), Δ is if the printed matter is slightly enlarged and the printed matter is blurred and the sharpness is poor. When the printed matter was insufficient, the printed matter was difficult to read.

(2) Non-transferability Ten heat-sensitive stencil sheets on which a thin layer was formed as described above were stacked, a weight of 50 kg / m ² was placed thereon, and the sheets were left at 35 ° C for 1 week. After that, the sticking prevention effect was measured by the above-mentioned method, and those having no change in sticking prevention effect before and after leaving were evaluated as ◯, those showing a slight decrease in effect were marked as Δ, and those markedly decreasing were marked as x. However, no measurement was made for those in which the stick was generated by 20% or more even before standing (indicated by-in the table).

Table 2 shows the results of the tests conducted as described above. In all the examples, clear prints were obtained and the non-transferability was excellent. When the viscosity of the silicone oil is low, as in the case of the comparative base paper 1, the sticking occurs, and when the viscosity is high (comparative base paper 8) or the coating amount is large (comparative base paper 7), the base paper is That's why it wasn't sent in the plate-making machine.

For comparison, a 2 μm film made of polyethylene terephthalate having a crystallinity of 45%, a shrinkage rate at 100 ° C. of 0% and a shrinkage stress of 0 g / m ² (shrinkage rate of 1% at 160 ° C., shrinkage stress of 50 g / mm ² ). When the film is perforated under the conditions of Example 2 of the base paper A, the perforation is insufficient due to poor sensitivity, and about 30 of the necessary portion (corresponding to the area of the element size of the thermal head) is required.
However, the printed result was unclear and the characters were blurred, making it difficult to read, but the sticking phenomenon still occurred and the level was "Δ". The non-transferability was Δ.

(Effect of the Invention) According to the present invention, the heat-sensitive stencil sheet has high sensitivity, high resolution,
It can be used for high-speed plate making, can be used under a wide range of plate making conditions, and can be used for a wide range of applications such as eliminating the need for a support. Further, a printed matter of higher quality than that of electrostatic copying (PPC) can be obtained.

Claims (2)

[Claims] 1. A heat-sensitive stencil film produced by a thermal head, wherein the thermoplastic resin constituting the film has a substantially amorphous level to a crystallinity of 15%. Is a stretched film having a thickness coefficient of 0.5 to 15 μm and made of a thermoplastic resin having a melt viscosity temperature coefficient (ΔT / ΔlogVI) of 100 or less, and has a heat shrinkage ratio (X%) at 100 ° C. of 100 ° C. Each heat shrinkage stress (Yg / mm ² ) is the following formula; 15 ≦ X ≦
Within the range of 80, 75 ≦ Y ≦ 500, and the relationship between them is within the range of −8X + 400 ≦ Y ≦ −10X + 1,000, and the viscosity at 25 ° C. is on one side of the film to be brought into contact with the thermal head. 10,000-50,000
A film for high-sensitivity and heat-sensitive stencil, characterized in that a thin layer mainly composed of 0CS of at least one silicone oil is provided in an amount of 0.05 to 1 g per unit area (m ² ). 2. A thermoplastic resin comprising a thermoplastic resin having a substantially amorphous level to a crystallinity of 15% and having a melt viscosity temperature coefficient (ΔT / ΔlogVI) of 100 or less. The heat shrinkage rate (X
%) And heat shrinkage stress (Yg / mm ² ) at 100 ° C. are in the ranges of the following formulas: 15 ≦ X ≦ 80, 75 ≦ Y ≦ 500, and the relationship between them is −8X + 400 ≦ Y ≦ −10.
Within the range of X + 1,000, the thickness is 0.5 to 15 μ.
m stretched film and printing ink can be transmitted, and a porous support which does not deteriorate substantially under the heating conditions at the time of perforation of the film is stacked, and the contact surface of the film is 25
A high-sensitivity, heat-sensitive stencil having a thin layer mainly composed of at least one silicone oil having a viscosity of 10,000 to 50,000 CS at a temperature of 0.05 to 1 g per unit area (m ² ). Raw paper.