JPH0525405A - Primer composition - Google Patents

Abstract

(57) [Summary] [Purpose] 1,1,1 resin molded products such as polypropylene
A primer composition which can be applied to the resin molded product to form a coating film having good adhesion and adhesion of a paint without vapor cleaning with a chlorine-based organic solvent such as trichloroethane. [Structure] A styrene / conjugated diene / block copolymer is graft-modified with a vinyl monomer and chlorinated, and has a vinyl monomer content of 0.5 to 15% by weight and a chlorine content of 10 to 10. A primer composition comprising 5 to 80 parts by weight of a chlorinated modified copolymer, which is 50% by weight, and 95 to 20 parts by weight of an organic solvent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primer composition, and more particularly to a primer composition which can be undercoated on various molded articles to improve the adhesion of the paint to the surfaces of the molded articles.

[0002]

2. Description of the Related Art Conventionally, the added value has been increased by coating the surface of a molded product of polyolefin such as polypropylene or by forming another resin layer. However, in general, polyolefin is poor in polarity,
Poor adhesion to general paints and other resins. Therefore, conventionally, the surface of the molded article has been previously treated with a primer to improve the adhesion and adhesion of the coating material to the surface.

Therefore, as a binder for a paint that can be applied once to a molded article directly without using a primer, styrene-butadiene.
In the presence of hydrogenated styrene block copolymer,
There has been proposed a resin composition for a coating obtained by polymerizing a (meth) acrylic acid ester, particularly a vinyl monomer having a hydroxyl group. (JP-A-63-51477)

[0004]

However, the above-mentioned Japanese Patent Laid-Open No.
The coating film obtained by using the resin composition for coating described in JP-A-3-51477 does not have sufficient peel strength. Moreover, in order to obtain a coating film having good adhesiveness and adhesion of the coating material, the conventional primer including this resin composition for coating material has 1,1,1-
It is necessary to perform steam cleaning with a chlorine-based organic solvent such as trichloroethane, which deteriorates the working environment during manufacturing and use, and the chlorine-based organic solvent used causes ozone layer depletion. It was

Therefore, an object of the present invention is to apply a good coating material to a resin molded product such as polypropylene without vapor cleaning the resin molded product with a chlorine-based organic solvent such as 1,1,1-trichloroethane. Another object of the present invention is to provide a primer composition capable of forming a coating film having the above-mentioned adhesiveness and adhesion.

[0006]

In order to solve the above problems, the present invention provides, as a first aspect, a styrene / conjugated diene / block copolymer or a hydrogenated product thereof which contains a hydroxyl group containing α, β-. The content of the α, β-unsaturated vinyl monomer having a hydroxyl group, which is obtained by further chlorinating a graft-modified copolymer obtained by graft-copolymerizing an unsaturated vinyl monomer, is 0.5 to 15% by weight. % And chlorine content 10
The present invention provides a primer composition containing 5 to 80 parts by weight of a chlorinated modified copolymer, which is ˜50% by weight, and 95 to 20 parts by weight of an organic solvent.

In a second aspect of the present invention, a styrene / conjugated diene / block copolymer or a chlorinated copolymer obtained by chlorinating a hydrogenated product of the styrene / conjugated diene / block copolymer has a hydroxyl group-containing α, β-unsaturation. The content of the α, β-unsaturated vinyl monomer having a hydroxyl group, which is obtained by graft copolymerizing a vinyl monomer, is 0.5 to 15% by weight, and the chlorine content is 10 to 50.
A primer composition comprising 5 to 80 parts by weight of a chlorinated modified copolymer and 95 to 20 parts by weight of an organic solvent is provided.

Further, the modified monomer is a (meth) acrylic acid ester of a monohydric alcohol and a mono (meth) acrylic acid ester of a polyhydric alcohol, wherein the α, β-unsaturated vinyl monomer having a hydroxyl group is used. It is preferable that it is at least one selected from

Hereinafter, the primer composition of the present invention will be described in detail.

The styrene / conjugated diene block copolymer or its hydrogenated product, which is the main constituent of the chlorinated modified copolymer constituting the primer composition of the present invention, is derived from one or more styrenes in the molecule. A styrene polymer block (S) which is a repeating structural unit and a conjugated diene polymer block (D) which is a repeating structural unit derived from one or more conjugated dienes. :

[Chemical 1] (Here, n is an integer of 1 or more).

Examples of the conjugated diene constituting the styrene / conjugated diene block copolymer include isoprene and butadiene. These conjugated dienes may be used alone or in combination of two or more in the styrene / conjugated diene block copolymer.

Such a styrene / conjugated diene block copolymer is produced by the method described in, for example, US Pat. No. 3,265,765 and JP-A-61-292743. And so on.

Among the styrene / conjugated diene block copolymers, specific examples in which the conjugated diene is isoprene include those commercially available as Califlex TR1107 and 1117 (both manufactured by Shell Chemical Co., Ltd.). Specific examples of the styrene / conjugated diene block copolymer in which the conjugated diene is butadiene include those commercially available as Kraton 1101 and 1102 (both manufactured by Shell Chemical Co., Ltd.).

The hydrogenated product of the styrene / conjugated diene block copolymer is, for example, Japanese Patent Publication No. 663/663.
6, Japanese Patent Publication No. 45-20504, Japanese Patent Publication No. 48
Examples include those manufactured by the method described in JP-A-3555. Among the hydrogenated products of this styrene / conjugated diene block copolymer, specific examples of those in which the conjugated diene is butadiene include those commercially available as Kraton G-1652 (manufactured by Shell Chemical Co., Ltd.).

These styrene / conjugated diene block copolymers or hydrogenated products thereof are gel permeated at 40 ° C. with tetrahydrofuran as a solvent from the viewpoint of peel strength and solid content concentration of the coating film of the primer composition of the present invention. The number average molecular weight measured by cation chromatography is preferably 1 × 10 ⁴ to 18 × 10 ⁴ , and particularly preferably 1.5 × 10 ^{4 to} 12 × 10 ⁴ . Further, the styrene content is preferably 10 to 60% by weight, particularly 12 to 55% by weight, from the viewpoints of adhesion, peel strength, low temperature characteristics, stickiness, etc. of the coating film of the primer composition of the present invention. Is preferred.

The chlorinated modified copolymer which is the main constituent of the primer composition of the present invention is (A) the styrene / conjugated diene / block copolymer or its hydrogenated product,
It may be obtained by a step of further chlorinating a graft-modified copolymer obtained by graft-copolymerizing an α, β-unsaturated vinyl monomer having a hydroxyl group, or (B) the styrene / conjugated diene / It may be obtained by a step of graft-copolymerizing an α, β-unsaturated vinyl monomer having a hydroxyl group on a chlorinated copolymer obtained by chlorinating a block copolymer or a hydrogenated product thereof.

First, a method for producing a chlorinated modified copolymer by the step (A) will be described below.

Examples of the α, β-unsaturated vinyl monomer having a hydroxyl group used for graft copolymerization (hereinafter, simply referred to as “vinyl monomer”) include hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth). ) Acrylate, 3-hydroxy (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate and other (meth) acrylic acid esters of monohydric alcohols; Glycerin mono (meth) acrylate, pentaerythritol mono (meth) acrylate, trimethylolpropane mono (meth) acrylate, tetraethylolethane mono (meth) acrylate, butanediol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate Mono- (meth) acrylic acid esters of polyhydric alcohols such as; 10-undecen-1-ol, 1-octen-3-ol, 2-methanol norbornene, hydroxystyrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-methylol Examples thereof include acrylamide, 2- (meth) acryloyloxyethyl acid phosphate, glycerin monoallyl ether, allyl alcohol, and allyloxyethanol. These may be used alone or in combination of two or more. Among these vinyl monomers, monohydric alcohol (meth) acrylic acid esters and polyhydric alcohol mono (meth) acrylic acid esters are particularly preferable.

This vinyl monomer is contained in the graft modified copolymer in an amount of 0.05 to 25% by weight, preferably 1 to 10% by weight, so that the graft copolymer is graft-copolymerized with the styrene / conjugated diene block copolymer. Polymerized.

The graft-modified copolymer used in the present invention can be produced by various known methods. For example, it can be carried out by graft-copolymerizing the vinyl monomer with the styrene / conjugated diene block copolymer in the presence of a radical polymerization initiator or in the presence or absence of an inert solvent.

As a method of graft copolymerization in the presence of an inert solvent, for example, a styrene / conjugated diene block copolymer is dissolved in an inert solvent to prepare a solution, and a vinyl monomer and radical polymerization are added thereto. Examples thereof include a method of adding an initiator and heating the mixture with stirring to cause a reaction. As an example of a preferable method, 10 to 3000 of a conjugated diene block copolymer of styrene is added to 1 m ³ of an inert solvent.
kg, preferably 20 to 1000 kg is dissolved to prepare a solution, and the vinyl monomer is contained in an amount of 0.5 to 100 mmol / min, preferably 1 to 20 mmol per 1 kg of the styrene / conjugated diene block copolymer. The radical polymerization initiator is added at a rate of about 5 × 10 ^{−5 to} 5 per 1 kg of the styrene / conjugated diene block copolymer at the same time.
There may be mentioned a method of sequentially adding and reacting at a rate of 0 mmol / min, preferably 10 ^{−2 to} 5 mmol / min.

At this time, the ratio of the radical polymerization initiator / vinyl monomer used is usually 1/100 to 3 / molar ratio.
The range of 5, preferably 1/20 to 1/2 is preferred.

The reaction temperature is 50 ° C. or higher, especially 80 to 20.
The range of 0 ° C. is suitable, and the reaction time is about 2 to 10 hours.

The reaction system may be either a batch system or a continuous system, but the batch system is preferred in order to carry out the graft copolymerization uniformly.

As a method for carrying out the graft copolymerization in the absence of an inert solvent, for example, the styrene / conjugated diene block copolymer is heated and melted at a temperature equal to or higher than the softening point of the vinyl monomer and radical polymerization. A method in which an initiator is added and reacted in a molten state with strong stirring; a styrene / conjugated diene block copolymer, a vinyl monomer and a radical polymerization initiator are mixed in advance, and the mixture is heated with an extruder. Examples thereof include a method of melting and extruding and graft-copolymerizing. In the method performed in the absence of these inert solvents, the amounts of the vinyl monomer and the radical polymerization initiator used and the proportions of the two used are the same as those used in the presence of the inert solvent.

The radical polymerization initiator used in the above graft copolymerization is, for example, benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di ( Peroxybenzoate) Hexin-
3,1,4-bis (t-butylperoxyisopropyl) benzene, lauroyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexyne-3,2,5-dimethyl-2,5 -Organic peroxides such as di (t-butylperoxy) -hexane; t-butyl peracetate, t-butyl perbenzoate, t-butyl perphenyl acetate, t-butyl perisobutyrate, t-butyl per-sec-octoate, t-
Examples thereof include organic peresters such as butyl perpivalate, cumyl perpivalate and t-butyl perdiethyl acetate; azo compounds such as azobisisobutyronitrile and dimethylazoisobutyronitrile. Of these, organic peroxides and organic peresters are preferred, and in particular dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,2. 5-dimethyl-2,5
Dialkyl peroxides such as -di (t-bitylperoxy) hexane and 1,4-bis (t-butylperoxyisopropyl) benzene are preferred.

When an inert solvent is used, specific examples of the inert solvent include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as hexane, heptane, octane and decane; trichloroethylene. , Halogenated hydrocarbons such as perchlorethylene, dichloroethylene, chlorobenzene, and the like. Among these, aromatic hydrocarbons are preferable, and alkyl group-substituted aromatic hydrocarbons are particularly preferable.

The chlorinated modified copolymer is obtained by chlorinating the graft modified copolymer thus obtained, and its chlorine content is usually about 15 to 40% by weight, preferably It is about 20 to 40% by weight.

The production of this chlorinated modified copolymer is carried out by introducing chlorine gas into the graft modified copolymer in a state of being dissolved or dispersed in an appropriate solvent until a predetermined chlorine content is reached. Can be done by. This reaction is generally performed at about 50 to 120 ° C. for about 0.5 to 5 hours. Further, in order to efficiently proceed this reaction, irradiation with ultraviolet rays or visible light,
Alternatively, a radical generator may be used.

Examples of the solvent used include aliphatic hydrocarbons such as hexane, heptane, octane, decane, dodecane and tetradodecane; alicyclic hydrocarbons such as methylcyclopentane, cyclohexane, methylcyclohexane, cyclooctane and cyclododecane. Hydrogen; benzene, toluene, xylene, ethylbenzene, cumene, ethyltoluene, trimethylbenzene, diisopropylbenzene, and other aromatic hydrocarbons; chlorobenzene, promobenzene, o-dichlorobenzene, carbon tetrachloride, carbon tetrabromide,
Examples thereof include halogenated hydrocarbons such as chloroform, promoform, trichloroethane, trichloroethylene, and tetrachloroethylene. These may be used alone or in combination of two or more.

Further, the chlorinated modified copolymer used in the primer composition of the present invention is not limited to that obtained in the step (A), and (B) the styrene / conjugated diene / block copolymer. Alternatively, it may be obtained by a step of graft-copolymerizing a modified monomer onto a chlorinated copolymer obtained by chlorinating the hydrogenated product. This chlorination and graft copolymerization can be performed in the same manner as the chlorination and graft copolymerization of the chlorinated modified copolymer in the step (A).

The primer composition of the present invention contains the chlorinated modified copolymer obtained as described above and an organic solvent.

Examples of the organic solvent used include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as hexane, heptane, octane and decane; alicyclic hydrocarbons such as cyclohexane, cyclohexene and methylcyclohexane. Hydrogen; aliphatic alcohols such as ethanol and isopropyl alcohol; ketone solvents such as acetone, methyl isobutyl ketone and methyl ethyl ketone; halogenated hydrocarbons such as trichloroethylene, dichloroethylene and chlorobenzene. These may be used alone or as a mixed system in which two or more kinds are combined. Among these, aromatic hydrocarbons are preferable, and alkyl-substituted aromatic hydrocarbons are particularly preferable.

In the primer composition of the present invention, the mixing ratio of the chlorinated modified copolymer and the organic solvent is 95 to 20 parts by weight of the organic solvent based on 5 to 80 parts by weight of the chlorinated modified copolymer. , Preferably chlorinated modified copolymers 7-6
The ratio is 93 to 40 parts by weight of the organic solvent with respect to 0 parts by weight.

Furthermore, the primer composition of the present invention contains, if necessary, a pigment; various stabilizers such as antioxidants, weather resistance stabilizers and heat resistance inhibitors; conductivity imparting agents such as carbon black and ferrite. May be.

Examples of pigments used include cadmium pigments such as titanium oxide, zinc oxide, lead white, red lead, cuprous oxide, red iron oxide, wet synthetic iron oxide, iron black, cadmium yellow, molybdenum red, silver vermilion, and the like. Examples include yellow lead, zinc chromate, chromium oxide, ultramarine blue, navy blue, carbon black, precipitated barium sulfate, barite powder, ordinary light calcium carbonate, ultrafine calcium carbonate, alumina white, and white carbon. These may be used alone or in combination of two or more.

The primer composition of the present invention is effective for improving the adhesion of the coating material to the surface of a molded article made of an olefin polymer or copolymer or other polymer. In particular, the primer composition of the present invention is, for example, an olefin polymer such as high-pressure polyethylene, medium-low-pressure polyethylene, polypropylene, poly-4-methyl-1-pentene, poly-1-butene; ethylene / propylene copolymer. It can be preferably used for a molded article made of an olefinic copolymer such as an ethylene / butene copolymer and a propylene / butene copolymer, or polystyrene.

Further, the primer composition of the present invention comprises, in addition to the above-mentioned olefin polymers and copolymers thereof, molded articles made of polypropylene and synthetic rubber, polyamide resins, unsaturated polyester resins, polybutylene terephthalate resins. Also, the present invention can be applied to a molded product made of a polycarbonate resin or the like, for example, a molded product such as a bumper for an automobile, and further a surface treatment of a steel plate, a steel plate for electrodeposition treatment or the like. In addition, polyuretene resin, fatty acid modified polyester resin, oil-free polyester resin, melamine resin,
A coating that is undercoated on the surface coated with a paint, primer, adhesive, etc. that contains epoxy resin as a main component to improve the adhesion of the paint, etc. to the surface and also has excellent image clarity and low temperature impact resistance. Can also be used to form

Further, the molded article to which the coating method of the present invention is applied is prepared by injection molding, compression molding, blow molding, extrusion molding, rotational molding, or any other known molding method in which the above various polymers or resins are used. It may be molded by a method.

The primer composition of the present invention is particularly suitable when a molded article to which the primer composition is applied is blended with an inorganic filler such as talc, zinc white, glass fiber, titanium white and magnesium sulfate, a pigment and the like. It is possible to form a primer coating film having good coating film adhesion.

In addition to the above, the molded article to which the primer composition of the present invention is applied may contain various stabilizers, ultraviolet absorbers, hydrochloric acid absorbers and the like.

As the stabilizer preferably used, for example, 2,6-di-t-butyl-4-methylphenol,
Tetrakis [methylene (3,5-di-t-butyl-4-
Hydroxyhydrocinnamate)] methane, metaoctadecyl-3- (4'-hydroxy-3,5-di-t-butylphenyl) propionate, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4 '
-Butylidene bis (3-methyl-6-t-butylphenol), 4,4'-thiobis (3-methyl-6-t-butylphenol), 2,2-thiobis (4-methyl-6)
-T-butylphenol), 1,3,5-trimethyl-
2,4,6-Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 1,3,5-tris (2
-Methyl-4-hydroxy-5-t-butylphenol) butane and other phenolic stabilizers; dilaurylthiodipropionate, distearylthiodipropionate and other sulfur stabilizers; tridecyl phosphite, trinonylphenylphosphine Phosphorus stabilizers such as phyto can be used.

Further, as the ultraviolet absorber used,
Examples thereof include 2-hydroxy-4-octoxybenzophenone, 2-ethylhexyl-2-cyano-3,3-diphenyl acrylate, p-octylphenyl salicylate and the like.

Examples of the hydrochloric acid absorbent include calcium stearate and the like.

As a method for applying the primer composition of the present invention to the surface of a molded article, spray coating is suitable, and for example, it is sprayed on the surface of the molded article with a spray gun.
The coating on the molded product may be carried out at room temperature, and after coating, it can be dried by an appropriate method such as natural drying or forced drying by heating to form a coating film.

As described above, the primer composition of the present invention is applied to the surface of a molded product and dried, and then the surface of the molded product is subjected to electrostatic coating, spray coating, brush coating, etc. Paint can be applied. Applying paint
After the undercoating, the method of overcoating may be performed. After applying the coating material, the coating film can be cured according to a usual method of heating with nichrome wire, infrared rays, high frequency, etc. to obtain a molded article having a desired coating film on the surface. The method of curing the coating film is appropriately selected depending on the material and shape of the molded product, the properties of the coating material used, and the like.

Further, the primer composition of the present invention can be applied to a wide range of applications other than the above-mentioned use as a primer for molded articles by taking advantage of its excellent adhesion, peeling strength and water resistance. Of course, it can be applied to applications such as adhesives and additives for paints.

[0048]

EXAMPLES Examples and comparative examples of the present invention will be given below.
The present invention will be specifically described, but the present invention is not limited to these examples. Further, in the following, the physical properties of the coating film were evaluated according to the following methods.

Cross-cut test According to the method of cross-cut test described in JIS K5400, a cross-cut test piece is prepared, and cellophane tape (manufactured by Nichiban Co., Ltd., trade name) is used for the cross-cut test. After sticking on the eye, it was quickly pulled in the direction of 90 ° to be peeled off, and the number of crosses not peeled out of the cross 100 was counted and used as an index of the adhesiveness.

Peeling test A coating film was prepared on a base material, a 1 cm width was cut with a cutter blade until the blade reached the base material, and the edges were peeled off.
180 at the speed of 50 mm / min.
The peel strength was measured by pulling in the direction of ° until the coating film peeled.

Water resistance test After immersing the test piece in water at 40 ° C. for 240 hours, the test piece was subjected to a cross-cut test and a peeling test to evaluate the adhesion and the peeling strength to evaluate the water resistance.

(Reference Example) 90 g of styrene and 140 g of benzene were charged in a reactor and heated to 40 ° C., then s
0.003 mol of ec-butyllithium was added and the temperature was adjusted to 4
Hold at 0 ° C. to polymerize all styrene. Next, add 420 g of new isoprene to the reactor, and further add 40 ° C.
Was polymerized with all isoprene. Thereafter, 90 g of styrene was newly added, and all styrene was polymerized at 40 ° C. to obtain a styrene / isoprene / styrene block copolymer.

[0053] styrene content and iodine value of the resulting styrene-isoprene-styrene block copolymer was measured. Respectively 30 wt%, 272gI _2/1
It was 00 g.

The styrene / isoprene / styrene block copolymer obtained above was dissolved in cyclohexane,
A solution having a concentration of 10% by weight was prepared. To this solution was added diatomaceous earth supporting a nickel catalyst in an amount of 0.5 g per 1 g of styrene / isoprene styrene block copolymer, and 145 to 1 under a hydrogen pressure of 35 kg / cm ^3.
The reaction was carried out at 55 ° C for 13 hours to obtain a hydrogenated product of a styrene / isoprene / styrene block copolymer.

The number average molecular weight and iodine value of the hydrogenated product of the obtained styrene / isoprene / styrene block copolymer were measured to be 4.6 × 10 ⁴ , respectively.
3.6gI was ₂ / 100g.

Example 1 Volume 1.5 equipped with stirrer
250 parts by weight of a hydrogenated product of the styrene / isoprene block copolymer produced in Reference Example and 500 parts by weight of toluene were charged into a 1-liter pressure reaction vessel, and heated to 160 ° C. with stirring. Then, 25 parts by weight of 2-hydroxypropyl acrylate and 6.5 parts by weight of di-t-butyl peroxide were added dropwise over 5 hours. After the dropping was completed, the temperature was maintained at 160 ° C. and the reaction was carried out for 2 hours while stirring. After the completion of the reaction, a large excess of acetone was added to the reaction mixture to precipitate a polymer, which was separated by filtration, washed repeatedly with acetone, and dried under reduced pressure to obtain a graft-modified styrene / isoprene block copolymer.

The content of 2-hydroxypropyl acrylate in the obtained graft-modified styrene / isoprene block copolymer was measured and found to be 4.2% by weight.

The graft-modified styrene / isoprene block copolymer obtained above was added to chlorobenzene at 110%.
It was completely dissolved at 0 ° C, and while keeping the temperature, the light was completely blocked, chlorine gas was introduced, and a chlorination reaction was performed for about 2 hours and 30 minutes. After completion of the reaction, a large excess of methanol was added to the reaction mixture to precipitate a polymer, which was separated by filtration, repeatedly washed with methanol, and dried under reduced pressure to obtain a chlorinated styrene-isoprene block copolymer.

The chlorine content of the obtained chlorinated styrene-isoprene block copolymer was measured and found to be 30
% By weight.

Next, the obtained chlorinated modified copolymer was dissolved in toluene to prepare a toluene solution having a polymer concentration of 20% by weight.

The toluene solution of the obtained chlorinated modified copolymer was applied to a square plate made of polypropylene (X440 manufactured by Mitsui Petrochemical Co., Ltd.) the surface of which was wiped with isopropyl alcohol, and the coating amount was 200 g / m ^2. Spray coating was performed so that Next, a urethane-based paint (R-271, manufactured by Nippon Bee Chemical Co., Ltd.) was dried to a thickness of 4 as an overcoat on this square plate.
A coating film was formed by coating so as to have a thickness of 0 μm. 1 at room temperature
After leaving it for 0 minutes, place it in an air oven at 85 ° C for 30 minutes.
A baking treatment was performed for a minute to obtain a coating film sample.

The obtained coating film sample was subjected to a cross-cut test and a peel test as it is and after the water resistance test. The results are shown in Table 1.

Comparative Example 1 The same square plate as used in Example 1 was steam washed with 1,1,1-trichloroethane, and then the chlorinated modified styrene-isoprene block prepared in Example 1 was used. A toluene solution of the copolymer was applied, and top coating was performed to prepare a coating film sample. This coating film sample was subjected to a cross-cutting test and a peeling test as it is and after the water resistance test. The results are shown in Table 1.

(Example 2) Coating was performed in the same manner as in Example 1 except that a square plate whose surface was washed with washing water (Tosoh Corporation, ID-112) was used instead of isopropyl alcohol. A coating film sample was prepared by performing the above, and this coating film sample was subjected to a cross-cut test and a peeling test as it is and after a water resistance test. The results are shown in Table 1.

Example 3 A coating film sample was prepared by coating in the same manner as in Example 1 except that a square plate whose surface was steam washed with 5-fluoropropanol was used instead of isopropyl alcohol. Created, this coating film sample as it is,
And after the water resistance test, it was subjected to a cross-cut test and a peeling test. The results are shown in Table 1.

(Examples 4 to 6) Coating films were prepared in the same manner as in Example 1 except that the resin square plates shown in Table 1 were used instead of the polypropylene square plates. Then, this coating film sample was subjected to a cross-cutting test and a peeling test as it is and after the water resistance test. The results are shown in Table 1.

[0067] Note: * 1 Ethylene content 24 mol%, MFR 10g /
10 minutes (ASTM D1238) * 2 A mixture of polypropylene and a partially cross-linked ethylene-propylene copolymer. Cross-cut test: Number of cross-cuts not peeled per 100 cross-cuts Peel strength: g / cm * 3 Cleaning method : A The surface was wiped with isopropyl alcohol. B The surface was washed with washing water. The surface was washed with C5-fluorinated propanol vapor.

[0068]

INDUSTRIAL APPLICABILITY The primer composition of the present invention is a resin molded product such as an α-olefin copolymer such as polypropylene, a synthetic rubber, an unsaturated polyester, an epoxy resin, a polyurethane resin, or a composite resin thereof. Since it has excellent adhesion to molded products made of various resins, it is possible to obtain a coating film having sufficient peel strength and adhesiveness by applying to the surfaces of these molded products.

Claims (3)

[Claims] 1. A graft-modified copolymer obtained by graft-copolymerizing a styrene / conjugated diene / block copolymer or a hydrogenated product thereof with an α, β-unsaturated vinyl monomer having a hydroxyl group, and further chlorine. The content of the α, β-unsaturated vinyl monomer having a hydroxyl group is 0.5 to 15
5-80 parts by weight of a chlorinated modified copolymer having a chlorine content of 10-50% by weight and an organic solvent of 95-
20 parts by weight of the primer composition. 2. An α, β-unsaturated vinyl monomer having a hydroxyl group is graft-copolymerized on a chlorinated copolymer obtained by chlorinating a styrene / conjugated diene / block copolymer or a hydrogenated product thereof. A chlorinated modified copolymer 5 having a content of the α, β-unsaturated vinyl monomer containing a hydroxyl group of 0.5 to 15% by weight and a chlorine content of 10 to 50% by weight.
-80 parts by weight and 95 to 20 parts by weight of an organic solvent. 3. The α, β-unsaturated vinyl monomer having a hydroxyl group is at least one selected from a (meth) acrylic acid ester of a monohydric alcohol and a mono (meth) acrylic acid ester of a polyhydric alcohol. The primer composition according to claim 1 or 2.