JP5023557B2 - Aqueous modified polyolefin resin composition - Google Patents

Description

  The present invention relates to an aqueous modified polyolefin resin composition having excellent adhesion to a nonpolar substrate during low temperature drying. More specifically, the present invention relates to an aqueous modified polyolefin resin composition in which the melting point of the aqueous resin composition after being made aqueous is 19 to 26 ° C. lower than the drying temperature.

  Conventionally, a propylene-based random copolymer modified with an acid such as a chlorinated polyolefin resin and an unsaturated carboxylic acid and / or an anhydride thereof having excellent adhesion to a hardly-adhesive polyolefin base material such as polypropylene and polyethylene. Polymers have been used as binders. Also in the automobile industry, the chlorinated polyolefin resin, unsaturated carboxylic acid and / or its anhydride, etc. as a binder for adhering difficult-to-adhere paint to the polyolefin of the base material (in the automobile industry, this is particularly called a primer) Propylene-based random copolymers modified with these acids have been used.

  In recent years, drying (baking) temperature tends to decrease in a coating line for automobile parts and the like mainly for the purpose of cost reduction and prevention of deformation of the base material. Furthermore, from the viewpoint of environmental problems, the propylene random copolymer has been shifted from a solvent-based primer to an aqueous primer, and has been modified with an acid such as the chlorinated polyolefin resin, unsaturated carboxylic acid and / or anhydride thereof. Water system is required.

  In “Patent Document 1” to “Patent Document 2” and the like, the primer contains an aqueous modified polyolefin resin composition having a low melting point resin as a base, or the minimum film forming temperature (MFT) is lower than a certain temperature. There has been proposed a method for improving the film-forming property during low-temperature baking by using the characteristic aqueous-modified polyolefin resin composition. However, conventional aqueous modified polyolefin resin compositions often have insufficient adhesiveness even though they have sufficient wettability and film-forming properties.

JP 2003-327761 A JP 2003-171512 A JP 2004-157711 A

An object of the present invention is to provide an aqueous modified polyolefin resin composition that exhibits excellent adhesion to a nonpolar substrate during low temperature drying.

  In order to achieve the above-mentioned object, the present inventors have intensively studied, and as a result, the melting point of the modified polyolefin resin composition after being made aqueous is 19 ° C. or higher and 26 ° C. or lower than the temperature at which the coating liquid containing the composition is dried. It was found that by using a low aqueous modified polyolefin resin composition within the range of the above range, the melting point of achieving the object can be achieved, and the present invention has been achieved. In the present specification, “low in a range of 19 ° C. or more and 26 ° C. or less” may be expressed as “19 ° C. to 26 ° C. low”.

That is, the present invention
(1) The melting point of the modified polyolefin resin composition after being made aqueous is 19 ° C. higher than the temperature at which the coating liquid is dried in the step of applying a coating liquid containing the resin composition on a substrate and drying to form a coating film. An aqueous modified polyolefin resin composition characterized by being low in the range of 26 ° C. or lower.
(2) The raw material polyolefin resin is modified with one or more kinds of polarity-imparting agents selected from chlorine, an unsaturated carboxylic acid and / or an anhydride thereof, and a radical polymerizable monomer. An aqueous modified polyolefin resin composition.
(3) The aqueous modified polyolefin resin composition according to (1) or (2), which contains a melting point regulator.
(4) The aqueous modified polyolefin resin composition according to (2), wherein the melting point modifier has a Hildebrand Parameter of 22 MPa ^1/2 or less.
(5) The method for producing an aqueous modified polyolefin resin composition according to any one of (1) to (4), wherein a melting point adjusting agent is added when the raw polyolefin resin is modified with a polarity-imparting agent and then made aqueous. .
(6) The method for adjusting the melting point of the aqueous modified polyolefin resin according to any one of (1) to (4), wherein the melting point of the aqueous modified polyolefin resin is lowered using a melting point adjusting agent.
(7) An aqueous modified polyolefin resin composition is coated on a substrate and dried at a high drying temperature in the range of 19 ° C. to 26 ° C. higher than the melting point of the aqueous modified polyolefin resin composition. Forming method.

  The present inventors have found that in order to improve the adhesion, it is necessary to increase the crystallinity within a range in which a film is sufficiently formed at a set drying temperature. In particular, in the case of low-temperature drying, it is difficult to balance the film forming property and crystallinity. According to the present invention, by making the melting point of the aqueous modified polyolefin resin composition 19 to 26 ° C. lower than the drying temperature, it is possible to obtain an aqueous modified polyolefin resin composition having high adhesion even at low temperature drying. The aqueous modified polyolefin resin composition of the present invention is suitable as an aqueous binder resin for low temperature drying. In particular, it is suitable as a primer resin for low-temperature baking.

  In general, in order to exhibit practically sufficient adhesiveness, it is an essential condition that the aqueous modified polyolefin resin composition is wetted by a substrate and further formed into a film. In order to obtain a film by drying the aqueous modified polyolefin resin composition at a target temperature, it is necessary to consider 1) the latent heat of water, 2) the mechanism of film formation, and the amount of heat required for drying compared to the solvent system. . Therefore, it is difficult for water-based products to cope with low-temperature baking compared to solvent-based products.

As countermeasures, 1) using a raw material resin having a low melting point, 2) optimizing the type and degree of modification, 3) adding an auxiliary such as a melting point adjusting agent, etc., the melting point and the minimum film-forming temperature (MFT) A method of lowering the value is effective. In addition, a method of improving the wettability to the base material and increasing the volatility of the solvent by adding alcohol or the like is also effective.
The inventors have found that the water-modified polyolefin resin composition is wetted on the base material, and sufficient adhesion cannot be obtained only by forming a film at the desired drying temperature, so that it has a certain degree of crystallinity. It is confirmed that the adhesion cannot be improved. In other words, in order to develop higher adhesion, it has been confirmed that it is important that the water-modified polyolefin resin composition is wetted by the base material, and it is important to balance the film-forming property and the crystallinity (Paint & Coatings Industry, p38, November 2005).

  However, particularly in the case of low-temperature drying, it is very difficult to balance the film forming property and crystallinity. This is because the physical properties of the two are contradictory to each other, that the crystallinity is lowered when the film-forming property is increased, and the film-forming property is lowered when the crystallinity is increased. The inventors have the best balance between the film-forming property and the crystallinity, regardless of the presence or absence of additives such as a melting point modifier, only when the aqueous modified polyolefin resin composition has a specific melting point. It has been found that it exhibits very good adhesion. In particular, the aqueous modified polyolefin resin composition of the present invention is suitable as a primer resin for automobile painting. The best mode is described below.

In this specification, drying means drying the water-modified polyolefin resin composition to evaporate water. Also, “drying” is sometimes referred to as “baking”. Baking refers to drying the paint mainly in a painting line for automobile parts and the like.
In the present invention, low temperature refers to a temperature lower than 120 ° C., and particularly refers to a range of 90 ° C. or lower and room temperature or higher.

  The modified polyolefin resin composition after making it aqueous according to the present invention refers to a dispersion of a modified polyolefin modified with a polarity-imparting agent in water. Moreover, the modified polyolefin resin composition after water-izing may be called aqueous modified polyolefin resin composition. In the present specification, a polyolefin resin that is a starting material for the aqueous modified polyolefin resin composition of the present invention may be referred to as a raw material polyolefin resin. In the present invention, the aqueous modified polyolefin resin composition is not limited to the aqueous modified polyolefin resin composition alone, and may contain other resins and auxiliaries. As will be described later, it is a preferred form to contain a melting point modifier.

  The nonpolar resin used as the adherend of the present invention refers to polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer sheet, film-formed product, and plate-shaped product. The water-modified polyolefin resin composition of the present invention is characterized in that it can be used even if these substrates are difficult-to-adhere with no surface treatment by plasma, corona, etc. Even materials can be used similarly.

  The raw material polyolefin resin used in the present invention is polypropylene, ethylene-propylene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer (hereinafter referred to as these) obtained by copolymerizing ethylene or α-olefin. And may be referred to as a propylene-based random copolymer). These resins may be used alone, or a plurality of resins may be mixed and used. As a polymerization catalyst for copolymerizing ethylene or α-olefin, a Ziegler-Natta catalyst or a metallocene catalyst can be used, but a metallocene catalyst is preferably used in order to cope with low temperature baking.

Known metallocene catalysts can be used. Specifically, a catalyst obtained by combining components (1) and (2) described below and (3) as necessary is desirable.
Component (1): a metallocene complex that is a transition metal compound of Groups 4 to 6 in the periodic table having at least one conjugated five-membered ring ligand.
-Component (2); ion-exchangeable layered silicate.
-Component (3); organoaluminum compound.

  Polyolefin resin synthesized using a metallocene catalyst is characterized by a narrow molecular weight distribution, excellent random copolymerizability, a narrow composition distribution, a wide range of comonomers that can be copolymerized, and a low propylene component content even with a low melting point. It is preferable as a raw material polyolefin resin of the present invention.

  Although the component composition of the raw material polyolefin resin of this invention is not specifically limited, It is preferable to use a propylene component 90 mol% or more. When 90 mol% or less is used, the adhesiveness to the polypropylene substrate is lowered.

  The molecular weight of the raw polyolefin resin of the present invention is not particularly limited. However, the weight average molecular weight of the modified polyolefin resin modified with a polarity-imparting agent described later is preferably 15,000 to 200,000. For this reason, when the weight average molecular weight of polyolefin resin is larger than 200,000, it is preferable to denature in the presence of heat or radicals to adjust the molecular weight to an appropriate range. In addition, the weight average molecular weight and molecular weight distribution (Mw / Mn) in this invention are the values measured by the gel permeation chromatography (standard material: polystyrene).

  In the present invention, the raw polyolefin resin is modified with a polarity imparting agent that imparts polarity to the raw polyolefin resin. As the polarity imparting agent, one or more selected from chlorine, an unsaturated carboxylic acid derivative and / or an anhydride thereof, and a radical polymerizable monomer are used. You may combine these 2 types or all 3 types.

  In the following description, when chlorine is used as a polarity-imparting agent, it is a chlorinated modified polyolefin resin, and when chlorine is not used as a polarity-imparting agent, it is a non-chlorinated modified polyolefin resin. Regardless of whether chlorine is used as the polarity-imparting agent, the polyolefin resin modified with the polarity-imparting agent is generally used as a modified polyolefin resin.

  The chlorine content in the chlorinated modified polyolefin resin is not particularly limited, but is preferably 2 to 35% by weight, particularly preferably 4 to 25% by weight. If it is less than 2% by weight, the adhesion to various nonpolar substrates is improved, but it becomes difficult to make it water-based. On the other hand, when it is more than 35% by weight, the adhesion to various nonpolar substrates is lowered. The chlorine content is a value measured according to JIS-K7229.

  In the present invention, the unsaturated carboxylic acid derivative and / or its anhydride means an unsaturated compound containing a carboxyl group and its anhydride, and the derivative means a mono- or diester, amide, imide, etc. of the compound. . For example, fumaric acid, maleic acid, itaconic acid, citraconic acid, aconitic acid, nadic acid and their anhydrides, methyl fumarate, ethyl fumarate, propyl fumarate, butyl fumarate, dimethyl fumarate, diethyl fumarate, fumarate Dipropyl acid, dibutyl fumarate, methyl maleate, ethyl maleate, propyl maleate, butyl maleate, dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, maleimide, N-phenylmaleimide, etc. Preferred are itaconic anhydride and maleic anhydride. Unsaturated carboxylic acid derivatives and / or anhydrides thereof can be used alone or in admixture of two or more.

  The graft weight of the unsaturated carboxylic acid derivative and / or anhydride thereof in the modified polyolefin resin is preferably 0.1 to 50% by weight, more preferably 0.5 to 15% by weight, particularly preferably 1.0 to 10% by weight. In the case where chlorine is not used as the polarity imparting agent, the content is preferably 0.5 to 20% by weight, particularly preferably 1.0 to 10% by weight in the non-chlorinated modified polyolefin resin.

When an unsaturated carboxylic acid derivative and / or an anhydride thereof is used alone as a polarity imparting agent, the chlorinated modified polyolefin resin is 0.1% by weight, and the nonchlorinated modified polyolefin resin is more than 0.5% by weight. When the graft weight is small, the adhesiveness of the adhesive composition to the polar adherend is lowered. On the other hand, when the amount is too large, a large amount of unreacted substances are generated, and adhesion to a non-polar non-adhered body is unfavorable.
Graft weight% of unsaturated carboxylic acid and / or derivative thereof was determined by alkali titration method or Fourier transform infrared spectroscopy.

  The radical polymerizable monomer in the present invention means a (meth) acrylic compound or a vinyl compound. The (meth) acrylic compound is a compound containing at least one (meth) acryloyl group in the molecule. For example, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl (meth) acrylate, hydroxyethyl (meth) acrylate, isobornyl (meth) acrylate, glycidyl (meta ) Acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, dimethylaminoethyl (meth) ) Acrylate, diethylaminoethyl (meth) acrylate, hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N, N-dimethylaminoethyl (Meth) acrylate, acetoacetoxyethyl (meth) acrylate, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) ) Acrylamide, N-isobutyl (meth) acrylamide, Nt-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-methylene-bis (Meth) acrylamide, N-methylol (meth) acrylamide, hydroxyethyl (meth) acrylamide, (meth) acryloylmorpholine, n-butyl vinyl ether, 4-hydroxybutyl vinyl ether, dodecyl vinyl ether, etc. That. These can be used alone or in admixture of two or more, and the mixing ratio can be freely set.

As the (meth) acrylic compound, those containing at least 20% by weight of at least one compound selected from (meth) acrylic acid esters represented by the following general formula (I) are preferable. When the (meth) acrylic compound is used, the molecular weight distribution of the modified polyolefin resin can be narrowed, and the adhesion and compatibility with other resins can be further improved.
(General Formula I) CH ₂ = CR ₁ COOR ₂ (I)
(In formula (I), R ₁ = H or CH ₃ , R ₂ = C _n H _{2n + 1} , n = integer of 8 to 18) ”

  The graft weight of the radical polymerizable monomer in the modified polyolefin resin is preferably from 0.1 to 30% by weight, particularly preferably from 1 to 20% by weight. When the radically polymerizable monomer is used alone as the polarity imparting agent, if the graft weight is less than 0.1% by weight, the compatibility and adhesion between the aqueous modified polyolefin resin composition and the other resin are lowered. On the other hand, if it is more than 30% by weight, the reactivity is high so that an ultra-high molecular weight body is formed, making the aqueous process difficult, and the amount of unreacted homopolymer or copolymer that does not graft onto the polyolefin skeleton increases. Therefore, it is not preferable.

  When chlorine is not used as the polarity imparting agent, the graft weight of the radical polymerizable monomer in the non-chlorinated modified polyolefin resin is preferably 0.1 to 30% by weight, particularly preferably 0.5 to 20% by weight.

  A method for obtaining a modified polyolefin resin by graft polymerization of an unsaturated carboxylic acid derivative and / or an anhydride thereof, and a radical polymerizable monomer as a polarity-imparting agent to a raw material polyolefin resin can be performed by a known method. For example, a polyolefin resin, a polar imparting agent, a solution method in which a mixture of a polyolefin resin and a polar imparting agent is heated and dissolved in a solvent such as toluene and a radical generator is added, a Banbury mixer, a kneader, an extruder, etc. And a method of obtaining a modified polyolefin resin by a melt kneading method in which a radical generator is added and kneaded. The method for adding the polarity imparting agent may be added all at once or sequentially.

Further, the order of graft polymerization of the polarizing agent to the polyolefin resin is not limited except in the following cases. Graft polymerization may be performed simultaneously, graft polymerization may be performed separately, or a polyolefin resin graft-polymerized with each component may be mixed.
When an unsaturated carboxylic acid derivative and / or an anhydride thereof and a radical polymerizable monomer are used as a polar imparting agent, styrene, o-, p-, α-methylstyrene, divinylbenzene, hexadiene, dicyclopentadiene are used as reaction aids. Etc. may be added.

  When using chlorine, an unsaturated carboxylic acid derivative and / or its anhydride, and a radically polymerizable monomer as a polarity imparting agent, the chlorination step may be performed before or after graft polymerization. It is preferable to end the process. That is, a method in which an unsaturated carboxylic acid derivative and / or an anhydride thereof and a radical polymerizable monomer are graft-polymerized to a polyolefin resin by the above-described solution method or melt-kneading method and then chlorinated by the method described later is preferable. However, if necessary, graft polymerization can be carried out after chlorination by a low temperature solution method. When a compound containing an ester such as (meth) acrylic acid ester is used as the radical polymerizable monomer, the ester may be decomposed by chlorination, so that these compounds are grafted after the chlorination step. Polymerization is preferred.

  As a method for chlorination, for example, after dissolving a polyolefin resin obtained by graft polymerization of a polarity imparting agent in a solvent such as chloroform, gaseous chlorine is blown while irradiating ultraviolet rays or in the presence of the radical generator. Thus, a method for obtaining a chlorinated modified polyolefin resin is preferred. The chlorine content is adjusted while monitoring the amount and time of chlorine injection because the introduction rate of chlorine varies depending on the type of polyolefin resin, reaction scale, reactor, and other factors.

  The radical generator used in the reaction for graft polymerization of the polarity imparting agent to the polyolefin resin can be appropriately selected from known ones, and an organic peroxide compound is particularly preferable. For example, di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, benzoyl peroxide, dilauryl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, 1,1-bis (t -Butylperoxy) -3,5,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) -cyclohexane, cyclohexanone peroxide, t-butylperoxybenzoate, t-butylperoxyisobutyrate, Examples thereof include t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisopropyl carbonate, cumylperoxyoctoate and the like.

The melting point of the modified polyolefin resin composition after being made aqueous according to the present invention is the modified polyolefin resin composition after being made aqueous, dried at 40 ° C. for 3 days, and then a trace melting point measuring device (Yanaco Instrument Development Laboratory Co., Ltd.). Manufactured by MP series). The drying temperature may be a temperature at which the melting point adjusting agent to be added does not volatilize when the melting point adjusting agent is added. There is no particular limitation when no melting point modifier is added. Detailed conditions are described below.
After drying the water-modified polyolefin resin composition for 3 days with an air dryer set at 40 ° C., the obtained solid was cut to a thickness of 0.5 to 1 mm, and about 1 to 3 mg of the solid was used as a slide glass. Place it between the preparations and place it on the sample stage of the micro melting point measurement device (MP series, manufactured by Yanaco Instrument Development Laboratory). The heater is heated at a temperature rising rate of 25 to 30 ° C./min, and the temperature of the heater when the solid starts to change and the temperature of the heater when the solid is completely melted are measured and averaged. The same measurement is repeated three times, and the average value of these three points is taken as the melting point in the present invention. At this time, the first decimal place is rounded off.

The present invention is characterized in that the melting point of the aqueous modified polyolefin resin composition is lowered in a range of 19 ° C. or higher and 26 ° C. or lower from the temperature at which the coating liquid containing the aqueous modified polyolefin resin composition is dried.
When the melting point of the aqueous modified polyolefin resin composition of the present invention is not lower than 19 ° C. below the drying temperature, for example, when the drying temperature is 80 ° C. and the melting point is higher than 61 ° C., a good film can be formed. It becomes difficult and the adhesive strength decreases. Further, when the melting point is 27 ° C. or more lower than the drying temperature, for example, when the drying temperature is 80 ° C., when the melting point is lower than 53 ° C., the film is formed well but the crystallinity of the resin is lowered. For this reason, the adhesive force to the substrate is reduced. That is, in the present invention, by using an aqueous modified polyolefin resin composition having a melting point that is lower than the drying temperature by 19 ° C. or more and 26 ° C. or less, the balance between film forming property and crystallinity is optimized and adhesion for low temperature drying is performed. As an adhesive resin, it exhibits maximum adhesive strength.

Methods for lowering the melting point of the aqueous modified polyolefin resin composition are broadly classified as follows.
(1) The raw polyolefin resin is modified with a polarity imparting agent.
(2) A melting point modifier is added when the modified polyolefin resin is made aqueous.
Of the above (1) and (2), (1) is essential for the resin of the present application from the viewpoint of adhesiveness. When the melting point of the aqueous modified polyolefin resin composition does not fall within the above-mentioned range due to the modification (1), the melting point of the aqueous modified polyolefin resin composition can be further lowered by using the method (2).

(1) The raw polyolefin resin is modified with a polarity imparting agent.
When chlorine is used as the polarity imparting agent, the melting point of the raw polyolefin resin can be greatly lowered by increasing the degree of chlorination through the chlorination step. However, if the degree of chlorination is too high, the adhesive force decreases, and therefore, a resin whose melting point is 20 ° C. lower to 60 ° C. higher than the drying temperature is preferred. In general, the chlorine content (degree of chlorination) for achieving the melting point of the present invention is preferably 2 to 35% by weight, but the melting point varies depending on the raw material resin even at the same degree of chlorination. Adjust the degree of chlorination while sampling the melting point of the resin.

  When chlorine is not used as the polarity imparting agent, the melting point after modification is difficult to decrease, that is, the melting point of the present invention is also difficult to decrease. It is preferable to use a resin having a high temperature. In general, the smaller the molecular weight, the lower the melting point. Therefore, the melting point of the present invention may be lowered by decreasing the melting point by reducing the molecular weight of the raw polyolefin resin by a known method such as thermal degradation.

  The melting point of the raw material polyolefin used in the present invention is preferably in the range as described above, but even if a raw material polyolefin having a melting point within the range is used, the melting point of the obtained aqueous modified polyolefin resin composition is If the condition that the temperature is lower than the drying temperature by 19 ° C. or more and 26 ° C. or less is not satisfied, the effect of the present invention is not exhibited.

(2) When making the modified polyolefin resin aqueous, a melting point adjusting agent is added.
Even when the melting point of the aqueous modified polyolefin resin composition does not fall within the above-described range due to the modification (1), the melting point can be lowered by adding a melting point adjusting agent when making the aqueous solution. Specifically, after the modified polyolefin is made aqueous, the following melting point modifier is added.

The melting point adjusting agent in the present invention is not particularly limited as long as it lowers the melting point of the aqueous modified polyolefin resin, but is preferably used as a film-forming auxiliary because it is preferable to improve adhesion. Is preferred. A film-forming aid is one that temporarily remains in the film during film formation, improves the film-forming property of the aqueous modified polyolefin resin composition by a plastic effect, and volatilizes after film formation. Common materials such as ethylene glycol and diethylene glycol can be used, but the Hildebrand Parameter must be 22 MPa ^1/2 or less. The Hildebrand Parameter indicates the polarity. The larger the value, the higher the polarity. When the Hildebrand Parameter is larger than 22 MPa ^1/2 , the polarity is too high and the water-modified polyolefin resin composition is not compatible.

As the film forming aid having a Hildebrand Parameter of 22 MPa ^1/2 or less, ethylene glycol mono-n-ethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-ethyl ether acetate, ethylene glycol methyl ether acetate, Examples include diethylene glycol-mono-ethyl ether, diethylene glycol-mono-n-butyl ether, and diethylene glycol-mono-ethyl ether acetate. Among them, in order to improve the adhesion with lowering the melting point of the present invention preferably has Hildebrand Parameter of 20 MPa ^1/2 or less, in particular those Hildebrand Parameter of 18 MPa ^1/2 or less preferred.

  The amount of film-forming aid added is sampled and added so that the melting point of the aqueous modified polyolefin resin composition is 19 to 26 ° C. lower than the drying temperature. Generally, 3 to 7 weight% is preferable with respect to the aqueous modified polyolefin resin composition.

  In the present invention, “aqueous” refers to a state in which the modified polyolefin resin is dispersed in water. The state of being dispersed in water refers to a state where it is not separated into two layers even if left for a certain period of time, or an emulsion (emulsified) state.

The aqueous modified polyolefin resin composition of the present invention is produced by dispersing a modified polyolefin resin in water. Any method such as a known forced emulsification method, phase inversion emulsification method, D phase emulsification method, or gel emulsification method may be used as the method of dispersing (emulsifying) in water. However, as will be described later, the average particle diameter of the aqueous modified polyolefin resin composition is preferably 300 nm or less. For this purpose, a phase inversion emulsification method or a composite agitation with high shear, a sand mill, a multi-screw extruder, etc. The method used is preferred.
When using a film-forming aid in the present invention, the modified polyolefin resin is added after making it aqueous.

In order to disperse and emulsify the modified polyolefin resin of the present invention in water, a surfactant can be used as necessary, and any of a nonionic surfactant and an anionic surfactant can be used. Nonionic surfactants are preferred because the water resistance of the emulsified aqueous modified polyolefin resin composition is better.

  Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene derivatives, polyoxyethylene fatty acid ester, polyoxyethylene polyhydric alcohol fatty acid ester, polyoxyethylene propylene polyol, sorbitan fatty acid ester, Polyoxyethylene hydrogenated castor oil, polyoxyalkylene polycyclic phenyl ether, polyoxyethylene alkylamine, alkylalkanolamide, polyalkylene glycol (meth) acrylate and the like can be mentioned. Preferably, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine and the like can be mentioned.

  As an anionic surfactant, alkyl sulfate ester salt, polyoxyethylene alkyl ether sulfate, alkylbenzene sulfonate, α-olefin sulfonate, methyl taurate, sulfosuccinate, ether sulfonate, ether carboxylate, Fatty acid salts, naphthalenesulfonic acid formalin condensates, alkylamine salts, quaternary ammonium salts, alkylbetaines, alkylamine oxides and the like are preferable, and polyoxyethylene alkyl ether sulfates, sulfosuccinates and the like are preferable.

  The addition amount of the surfactant is 0.1 to 30% by weight, more preferably 5 to 20% by weight with respect to the modified polyolefin resin. When it exceeds 30% by weight, the excess emulsifier more than the amount that forms the water-modified polyolefin resin composition causes the adhesiveness and water resistance to be remarkably lowered, and when it is used as a dry film, it causes a plastic effect and a bleed phenomenon. This is not preferable because blocking is likely to occur.

  The pH of the aqueous modified polyolefin resin composition in the present invention is preferably 5 or more, more preferably 6 to 10. When the pH is less than 5, neutralization is insufficient, so that the modified polyolefin resin does not disperse in water, or even if dispersed, precipitation and separation are likely to occur with time, and storage stability is deteriorated. On the other hand, when the pH exceeds 10, there is a problem in compatibility with other components and work safety. If necessary, a basic substance can be added for the purpose of neutralizing the acidic component in the modified polyolefin resin and dispersing it in water.

  Preferably, the basic substance is sodium hydroxide, potassium hydroxide, ammonia, methylamine, propylamine, hexylamine, octylamine, ethanolamine, propanolamine, diethanolamine, N-methyldiethanolamine, dimethylamine, diethylamine, triethylamine, N , N-dimethylethanolamine, 2-dimethylamino-2-methyl-1-propanol, 2-amino-2-methyl-1-propanol, morpholine, etc., more preferably ammonia, triethylamine, 2-amino-2. -Methyl-1-propanol, morpholine and the like. The amount used can be arbitrarily added according to the amount of the acidic component of the modified polyolefin resin, but it must be added so that the pH of the aqueous modified polyolefin resin composition is 5 or more, preferably 6 to 10.

  When obtaining a modified polyolefin resin, a surfactant is used when grafting an unsaturated carboxylic acid derivative and / or its anhydride and a radical polymerizable monomer as a polarity imparting agent with a high degree of modification and imparting these self-emulsifying properties. It can be emulsified without. In that case, for example, sodium hydroxide or potassium hydroxide is preferably used as the strongly basic substance.

  In the aqueous modified polyolefin resin composition of the present invention, the average particle size of the resin emulsified and dispersed in water is preferably adjusted to 300 nm or less, more preferably 200 nm or less. When it is 300 nm or more, the storage stability of the water-modified polyolefin resin composition and the compatibility with other resins deteriorates, and further, film properties such as adhesion to a substrate, solvent resistance, water resistance, and blocking resistance. Decreases. In addition, the particle size can be reduced as much as possible by increasing the amount of the emulsifier, but in this case, the physical properties of the film such as adhesion to the base material, water resistance, gasohol resistance, etc. tend to decrease. Becomes easier to appear. In addition, the average particle diameter in this invention is obtained by the particle size distribution measurement using the light-diffusion method. The particle diameter can be adjusted by the amount and type of emulsifier added, the stirring force when emulsifying the resin in water, and the like.

  In the present invention, a crosslinking agent may be used in the aqueous modified polyolefin resin composition. A crosslinking agent means a compound that reacts with a hydroxyl group, carboxyl group, amino group, etc. present in a modified polyolefin resin, surfactant, basic substance, etc. to form a crosslinked structure, and is itself water-soluble. Those that are dispersed in water by some method can be used. Specific examples include blocked isocyanate compounds, aliphatic or aromatic epoxy compounds, amine compounds, amino resins, and the like. The method for adding the crosslinking agent is not particularly limited. For example, it can be added during or after the hydration process.

  The aqueous modified polyolefin resin composition of the present invention includes an aqueous acrylic resin, an aqueous urethane resin, a lower alcohol, a lower ketone, a lower ester, an antiseptic, a leveling agent, an antioxidant, a light stabilizer, if necessary. Ultraviolet absorbers, dyes, pigments, metal salts, acids and the like can be blended.

  The aqueous modified polyolefin resin composition of the present invention is particularly excellent in adhesiveness when dried at a low temperature, and can be used as an adhesive for non-polar substrates, a primer, a binder resin for paints, and a binder resin for inks. Moreover, you may change and use into forms, such as a solution, a powder, a sheet | seat, according to the necessity, such as a use. At that time, additives such as antioxidants, light stabilizers, ultraviolet absorbers, pigments, dyes, inorganic fillers and the like can be blended as necessary.

  The aqueous modified polyolefin resin composition of the present invention is particularly suitable as a primer resin used for low temperature baking. Excellent adhesion to top coat and clear when dried at low temperature. In the present specification, the primer refers to a binder for adhering a hardly-adhesive paint to the nonpolar resin serving as a base material, and includes the aqueous modified polyolefin resin composition of the present invention as an adhesive component. Further, the primer may contain a paint component or other resin.

  By applying a coating liquid containing the aqueous modified polyolefin resin composition of the present invention on a substrate and drying at a drying temperature 19 ° C. to 26 ° C. higher than the melting point of the aqueous modified polyolefin resin composition, adhesion and A film having various physical properties can be formed.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to this.
(Production Examples 1-4)
Propylene-based random copolymer produced using a metallocene catalyst as a polymerization catalyst (propylene content: 96 wt%, ethylene content: 4 wt%, MFR = 2.0 g / min, melting point (Tm) = 125 ° C.) at a barrel temperature of 350 ° C. A propylene-based random copolymer having a melt viscosity of about 1500 mPa · s at 190 ° C. was obtained by supplying to the set twin screw extruder for thermal degradation. After thoroughly mixing 100 parts by weight of the degraded propylene random copolymer, 4 parts by weight of maleic anhydride and 3 parts by weight of dicumyl peroxide in advance, a twin screw extruder (L / D = 34, Φ = 40 mm, first Barrel to 8th barrel), residence time is 5 minutes, rotation speed is 300 rpm, barrel temperature is 120 ° C. (first and second barrels), 180 ° C. (third and fourth barrels), 100 ° C. (fifth barrel) The reaction was carried out under the conditions of 130 ° C. (6-8 barrels), and unreacted maleic anhydride was removed by decompression treatment of 6-8 barrels to obtain a maleic anhydride-modified propylene copolymer. . 2 kg of this resin was put into a glass-lined 50 L reaction kettle, 20 L of chloroform was added, and gaseous chlorine was blown from the bottom of the reaction kettle while irradiating ultraviolet rays under a pressure of ² kg / cm ² . In order to adjust the chlorine content, sampling was performed to obtain samples with chlorination content of 15.2, 19.1, 20.4, 21.6% by weight (Production Example 1 in order of decreasing chlorine content). 2, 3, 4). Next, chloroform as a solvent was distilled off with an evaporator, and each was adjusted to a solid content of 30% by weight. After adding a stabilizer (t-butylphenyl glycidyl ether) to the chloroform solution at 1.5% by weight with respect to the resin, a twin screw extruder (L / D = 34, Φ = 40 mm, first to seventh barrels) Solidification was performed under the conditions of a residence time of 10 minutes, a rotation speed of 50 rpm, a barrel temperature of 90 ° C. (first to sixth barrels), and 70 ° C. (seventh barrel). The first and fourth to sixth barrels were subjected to reduced pressure treatment to obtain four types of maleic anhydride-modified chlorinated propylene random copolymers having different chlorine contents.
In a 2 L four-necked flask equipped with a stirrer, a condenser, a thermometer and a dropping funnel, 200 g of the obtained maleic anhydride-modified chlorinated propylene-based random copolymer and a surfactant (polyoxyethylene alkylamine) ), 35 g of stabilizer (stearyl glycidyl ether) and 36 g of toluene were added and kneaded at 120 ° C. for 30 minutes. Next, 8 g of 2-amino-2-methyl-1-propanol was added over 5 minutes, and after maintaining for 5 minutes, 970 g of warm water at 90 ° C. was added over 40 minutes. After performing the pressure reduction process and removing toluene, it cooled, stirring to room temperature, and obtained the water-modified polyolefin resin composition.

(Production Examples 5-8)
While stirring 100 g of the aqueous modified polyolefin resin composition obtained in Production Examples 1 to 4, 5 g of ethylene glycol mono-n-butyl ether (Hildebrand Parameter = 19.4 MPa ^1/2 ) was sequentially added as a melting point modifier.

(Production Examples 9-12)
While stirring 100 g of the aqueous modified polyolefin resin composition obtained in Production Examples 1 to 4, 5 g of diethylene glycol-mono-ethyl ether acetate (Hildebrand Parameter = 17.4 MPa ^1/2 ) was sequentially added as a melting point adjusting agent.

(Production Example 13)
100 parts by weight of a propylene random copolymer produced using a metallocene catalyst as a polymerization catalyst (propylene content: 88 wt%, ethylene content: 12 wt%, weight average molecular weight: 55,000, Tm = 70 ° C.), maleic anhydride: 4 parts by weight Then, 4 parts by weight of methyl methacrylate and 3 parts by weight of dicumyl peroxide were reacted using a twin screw extruder set at 180 ° C. Deaeration was also performed in the extruder to remove the remaining unreacted matter, and a modified propylene random copolymer was obtained.
In a four-necked flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel, 200 g of the obtained modified polyolefin resin composition, 35 g of a surfactant (polyoxyethylene alkylamine) and 36 g of toluene were added, and 120 The mixture was kneaded at 30 ° C for 30 minutes. Next, 7 g of dimethylethanolamine was added over 5 minutes and held for 5 minutes, and then 970 g of 90 ° C. ion exchange water was added over 40 minutes. Subsequently, the mixture was cooled to room temperature with stirring to obtain an aqueous modified polyolefin resin composition.

(Production Example 14)
100 parts by weight of a propylene random copolymer produced using a metallocene catalyst as a polymerization catalyst (propylene content: 92 wt%, ethylene content 8 wt%, weight average molecular weight 50,000, Tm = 95 ° C.), maleic anhydride 8 weight Part, 8 parts by weight of stearyl methacrylate, and 4 parts by weight of di-t-butyl peroxide were reacted using a twin screw extruder set at 180 ° C. Deaeration was also performed in the extruder to remove the remaining unreacted matter, and a modified propylene random copolymer was obtained. An aqueous modified polyolefin resin composition was obtained in the same manner as in Production Example 13 except that the obtained resin was changed to 12 g of dimethylethanolamine.

(Production Example 15)
In Production Example 14, the same modification reaction was carried out by changing to 4 parts by weight of maleic anhydride, 3 parts by weight of stearyl methacrylate, and 2 parts of di-t-butyl peroxide. An aqueous modified polyolefin resin composition was obtained from the obtained resin in the same manner as in Production Example 13.

(Production Example 16)
In Production Example 14, the same modification reaction was carried out by changing to 2 parts by weight of maleic anhydride, 2 parts by weight of stearyl methacrylate, and 1 part of di-t-butyl peroxide. An aqueous modified polyolefin resin composition was obtained in the same manner as in Production Example 13 except that the obtained resin was changed to 3 g of dimethylethanolamine.

  About the water-modified polyolefin resin composition obtained by the manufacture example, various physical properties and performance were measured with the following method, and the result was shown to Tables 1-4. Tables 1 to 4 also show comparisons between production examples and examples.

<Method of measuring physical properties>
The chlorine content, the weight average molecular weight, and the acid / acrylic graft ratio were measured using a modified polyolefin resin, and other measurements were performed using an aqueous modified polyolefin resin composition.
(1) Chlorine content: Measured according to JIS-K7229.
(2) Weight average molecular weight (Mw): Measured by GPC (standard substance: polystyrene resin).
(3) Graft ratio of unsaturated carboxylic acid and / or derivative thereof (hereinafter referred to as graft ratio A): determined by an alkali titration method.
(4) Graft ratio of radical polymerizable monomer (hereinafter referred to as graft ratio B): determined by alkali titration method. In the case of ester etc. which do not have an acid group, it calculated | required by FT-IR.
(5) Melting point: After drying the aqueous modified polyolefin resin composition at 40 ° C. for 3 days, the resulting solid was cut to a thickness of 0.5 to 1 mm, and about 1 to 3 mg of the slide glass and prepared slide And placed on a sample stage of a micro melting point measuring apparatus (MP-500D manufactured by Yanaco Device Development Laboratory Co., Ltd.). The heater was heated at a temperature increase rate of 25 to 30 ° C./min, and the temperature of the heater when the solid began to change and the temperature of the heater when the solid completely melted were measured and averaged. The same measurement was repeated three times, and the average of these three points was taken as the melting point.
(6) Average particle size: Measured with a particle size distribution measuring apparatus (manufactured by Malvern Instruments).

<Performance evaluation items and test method of water-modified polyolefin resin composition>
(1) Peel strength: The adhesion strength of the present invention means the peel strength between the nonpolar substrate and the dry film of the aqueous modified polyolefin resin composition. Measurement was performed at room temperature by a surface-interface cutting method (SAICAS method, manufactured by Daipura Wintes). A sample for measurement was prepared by the following procedure.
(Sample Preparation) An aqueous modified polyolefin resin composition was spray-coated on an ultra-high rigidity polypropylene plate degreased with isopropanol so that the dry film thickness was 10 to 15 μm and preheated at 80 ° C. for 10 minutes. Thereafter, baking was performed at 80 ° C. for 30 minutes or 90 ° C. for 20 minutes. After standing at room temperature for 5 days, a peel strength test was conducted.
The peel strength measured by the SAICAS method is in the range of about 0.20 to 1.00 kg / cm, depending on the type of substrate, baking temperature, type of additive, etc., and the difference is 0.1 kg / It can be considered that there exists a significant difference as peeling strength that it is cm or more.

(2) High-pressure car wash resistance A portion of an ultra-high-rigidity polypropylene plate degreased with isopropanol is masked, and an aqueous modified polyolefin resin composition is spray-coated so that the dry film thickness is 10 to 15 μm, and 80 ° C. For 10 minutes. Next, the two-pack type top coat white paint was spray-coated so that the dry film thickness was 45 to 50 μm, and allowed to stand at room temperature for 15 minutes, and then baked at 80 ° C. for 30 minutes or 90 ° C. for 20 minutes. . Pressurized water having a height of 20 cm to 20 ° C. and a water pressure of 50 kgf / cm ² was sprayed for 30 seconds to the boundary between the unpainted test piece and the coating film. The state of the coating film after spraying was observed, and evaluation was made with ○ indicating that there was no change in the coating film, Δ indicating that the coating film was slightly changed, and × indicating that the coating film was peeled off.

  From the results in Table 2, it can be seen that when the melting point of the modified polyolefin resin composition after being made aqueous is 19 ° C. to 26 ° C. lower than the drying temperature, the peel strength is high and it is suitable for high-pressure car washing.

From the results of Table 4, it can be seen that when the melting point of the modified polyolefin resin composition after being made aqueous is 19 ° C. to 26 ° C. lower than the drying temperature, the peel strength is high and it is suitable for high-pressure car washing.

Claims (6)

In the method for forming a film, in which an aqueous modified polyolefin resin composition is coated on a substrate and dried at 80 to 90 ° C., the melting point of the aqueous modified polyolefin resin composition is in the range of 19 ° C. or higher and 26 ° C. or lower from the drying temperature. A method for forming a coating film characterized by being low. The aqueous modified polyolefin resin composition is characterized in that the raw polyolefin resin is modified with one or more kinds of polarity imparting agents selected from chlorine, unsaturated carboxylic acid and / or anhydride thereof, and radical polymerizable monomer. The method for forming a film according to claim 1. The method for forming a film according to claim 1, wherein the aqueous modified polyolefin resin composition contains a melting point modifier. The method for forming a coating film according to claim 2, wherein the melting point adjusting agent has a Hildebrand Parameter of 22 MPa1 ^{/ 2} or less. The coating film according to claim 1, wherein the aqueous modified polyolefin resin composition is produced by adding a melting point adjusting agent when the aqueous polyolefin resin composition is modified with a polarity imparting agent and then made aqueous. Forming method. The method for forming a film according to claim 1, wherein the melting point of the aqueous modified polyolefin resin composition is lowered using a melting point modifier.