JP2984331B2 - Water dispersion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to an aqueous dispersion, and in particular, it can improve the adhesion of a paint to the surface of a molded article by undercoating various resin molded articles, The present invention relates to an aqueous dispersion suitable as a primer, which does not contain an organic solvent and can maintain a favorable working environment.

<Conventional technology> Conventionally, the surface of a molded article of polyolefin such as polypropylene is painted, or another resin layer is formed,
The added value is being increased. However, polyolefins generally have poor polarity and poor adhesion to general paints and other resins. Therefore, conventionally, it has been attempted to improve the adhesion of paint by treating the surface of a molded article in advance with chromium scattering, flame, corona discharge, plasma, solvent, or the like to increase the polarity of the surface. However, in these treatments, there are disadvantages that complicated treatments are required and dangers are involved due to the use of corrosive chemicals. In addition, there is a disadvantage that strict process control is required to obtain a stable processing effect.

Therefore, as an effective means to improve these disadvantages,
This is a method of coating the surface of a molded article or the like with a primer, and various surface treatment agents obtained by further chlorinating polypropylene graft-modified with a specific carboxyl group-containing compound have been proposed as the primer. (Japanese Patent Publication No. 50-10916, JP-A-55-149304, JP-A-61-108608) <Problems to be Solved by the Invention> However, these conventional surface treatment agents contain insoluble components. Or does not have sufficient adhesiveness and heat resistance,
In addition, since it has poor solubility in solvents, when applied as a primer, a coating film having sufficient smoothness cannot be obtained, and there are disadvantages such as a decrease in the appearance of a molded product, particularly, gloss. Further, all of these conventional surface treatment agents contain an organic solvent or are used after being dissolved in an organic solvent. However, this organic solvent causes a problem that the working environment during production and use is deteriorated. There is. Therefore, in recent years, a surface treatment agent that does not contain an organic solvent has been required in order to reduce the amount of the volatile organic solvent used and maintain a favorable working environment in a factory.

Accordingly, an object of the present invention is to provide a resin molded article, for example, adhesion to a molded article made of various resins such as polyolefin such as polypropylene, synthetic rubber, unsaturated polyester, epoxy resin, polyurethane resin, or a composite resin thereof. Because it is excellent in, it is possible to obtain a coating film having sufficient peel strength and adhesion by applying to the surface of these molded articles, and because it is an aqueous solution containing no organic solvent,
An object of the present invention is to provide an aqueous dispersion suitable as a primer, which can maintain a favorable working environment.

<Means for Solving the Problems> In order to solve the above problems, the present invention comprises propylene and / or 1-butene as a main component and has an intrinsic viscosity [η].
Is a modified polymer obtained by graft copolymerizing a polyolefin having a dl / g or more with an α, β-vinyl monomer having a hydroxyl group, the modified polymer having an intrinsic viscosity of 0.4 to 1 dl / g. Further, the present invention provides an aqueous dispersion obtained by dispersing chlorinated modified polyolefin having a chlorine content of 10 to 40% by weight obtained by chlorination in water.

Further, the α, β-vinyl monomer having a hydroxyl group is
It is preferable that at least one selected from a monohydric alcohol mono (meth) acrylate and a polyhydric alcohol mono (meth) acrylate.

 Hereinafter, the aqueous dispersion of the present invention will be described in detail.

The chlorinated modified polyolefin, which is the main component of the aqueous dispersion of the present invention, is a modified polymer obtained by graft copolymerizing a polyolefin having an α, β-vinyl monomer having a hydroxyl group,
It is obtained by further chlorination. The polyolefin which is a main component of the chlorinated modified polyolefin is mainly composed of propylene and / or 1-butene. For example, propylene homopolymer, 1-butene homopolymer, propylene and 1-butene Butene copolymer or propylene and / or 1-butene and other α
-Copolymers with olefins. In this polyolefin, the content of propylene is usually about 90 mol% or more. Examples of the other α-olefin include ethylene, 1-pentene, 1-hexene, 1-octene, 1-decene, and 4-methyl-1-pentene. In the present invention, one or more of these other α-olefins may be included in the polyolefin. When the polyolefin contains another α-olefin, its content is usually at most 40 mol%, preferably at most 30 mol%.

The intrinsic viscosity [η] of this polyolefin is such that an aqueous dispersion which has a high cohesive force and can maintain a good appearance even when subjected to heat treatment after being applied to a molded article is obtained. Is 1 dl / g or less, preferably 1 to 10 dl / g, particularly preferably 1.5 to 7 dl / g. Here, the intrinsic viscosity [η] in the present invention is a value measured in decalin at 135 ° C. As such a polyolefin, those having a crystallinity of 5% or more by X-ray diffraction are preferable.

In the present invention, in order to obtain a modified polymer, an α, β-vinyl monomer having a hydroxyl group to be graft-copolymerized to the polyolefin as described above (hereinafter, simply referred to as “vinyl monomer”) includes: For example, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) ) (Meth) acrylates of monohydric alcohols such as acrylates; glycerin mono (meth) acrylate, pentaerythritol mono (meth) acrylate, trimethylolpropane mono (meth) acrylate, tetraethylolethane mono (meth) acrylate, Butanediol mono ( Mono (meth) acrylates of polyhydric alcohol such as meth) acrylate and polyethylene glycol mono (meth) acrylate; 10-undecene-1-ol, 1-octen-3-ol, 2-
Methanol norbornene, hydroxystyrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-methylol acrylamide, 2- (meth) acryloyloxyethyl acid phosphate,
Glycerin monoallyl ether, allyl alcohol, allyloxyethanol and the like can be mentioned. These may be used alone or in combination of two or more. Among these vinyl monomers, in particular, the (meth)
Acrylic acid esters and acrylic acid esters of polyhydric alcohols are preferred, and 2-hydroxypropyl acrylate is particularly preferred.

In the present invention, the modified polymer has a high intrinsic viscosity [η] in that the modified polymer has a high cohesive force and an aqueous dispersion capable of maintaining a good appearance even after being heat-treated after being applied to a molded article is obtained.
Is 0.4 to 1 dl / g, preferably 0.5 to 1 dl / g.

The production of the modified polymer as described above can be performed according to various known methods. For example, it can be carried out by graft copolymerizing the vinyl monomer with the polyolefin in the presence of a radical polymerization initiator, in the presence or absence of an inert solvent.

As a method for graft copolymerization in the presence of an inert solvent, for example, a polyolefin is dissolved in an inert solvent to prepare a solution, a vinyl monomer and a radical polymerization initiator are added thereto, and the mixture is heated while stirring. To react;
A method in which a powdery polyolefin is impregnated with a solution obtained by dissolving a vinyl monomer and a radical polymerization initiator in an inert solvent, followed by heating to a temperature at which the powder does not dissolve and reacting the mixture.

At this time, the ratio of the radical polymerization initiator / vinyl monomer used is usually 1/100 to 3/5, preferably 1/20, in molar ratio.
It is in the range of ~ / 1/2. The reaction is preferably carried out with heating and stirring. The reaction system may be a batch system or a continuous system, but in order to perform the graft copolymerization uniformly,
Batch systems are preferred.

Examples of a method for performing graft copolymerization in the absence of an inert solvent include, for example, a method in which a polyolefin is heated and melted, and a vinyl monomer and a radical polymerization initiator are added and reacted while stirring; polyolefin, vinyl Premix the monomer and radical polymerization initiator,
A method in which the mixture is heated and melted by an extruder and graft-copolymerized while extruding the mixture may, for example, be mentioned. In the method performed in the absence of these inert solvents, the amount of the vinyl monomer and the radical polymerization initiator used, and the ratio of both used are the same as in the method performed in the presence of the above-described inert solvent. .

Examples of the radical polymerization initiator used for the graft copolymerization include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide,
t-butyl peroxide, 2,5-dimethyl-2,5-di (peroxybenzoate) hexyne-3,1,4-bis (t
-Butylperoxyisopropyl) benzene, lauroyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexyne-3,2,5-dimethyl-2,5-di (t-butylperoxy)- Organic peroxides such as hexane; t-butyl peracetate, t-butyl perbenzoate, t-butyl perphenyl acetate, t-butyl perisobutyrate, t-butyl per-sec-octoate, t-butyl perpivalate, cumyl Organic peresters such as perpivalate and t-butyl perdiethyl acetate; azo compounds such as azobisisobutyronitrile and dimethylazoisobutyronitrile; Of these, organic peroxides and organic peresters are preferred, especially dicumyl peroxide, di-t
-Butyl peroxide, 2,5-dimethyl-2,5-di (t-
Butylperoxy) hexyne-3,2,5-dimethyl-2,5
Dialkyl peroxides such as -di (t-butylperoxy) hexane and 1,4-bis (t-butylperoxyisopropyl) benzene are preferred.

The reaction temperature is usually 80 to 25 when using an organic solvent.
About 0 ° C, when using an extruder, usually 150-350 ° C
Range.

 The reaction time is about 0.5 to 6 hours.

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

The aqueous dispersion of the present invention is mainly composed of a chlorinated modified polyolefin obtained by further chlorinating the modified polymer obtained as described above. This chlorinated modified polyolefin is easily dissolved in a solvent, the production of an aqueous dispersion by the solvent replacement method described later is facilitated, and the adhesion with a molded article of polypropylene is improved, and the chlorine content is 10%.
-40% by weight, preferably 15-35% by weight. Further, the intrinsic viscosity of the chlorinated modified polyolefin is usually about 0.1 to 1 dl / g, preferably about 0.3 to 0.8 dl / g,
It has a degree of crystallinity of about 0 to 20%.

The production of the chlorinated modified polyolefin can be carried out by dissolving or dispersing the modified polymer in a suitable organic solvent and then reacting it with chlorine gas. This reaction is generally performed at about 50 to 120 ° C. for about 0.5 to 5 hours. Further, in order to make the reaction proceed efficiently, ultraviolet rays or visible rays may be irradiated, or a radical polymerization initiator may be used.

Examples of the organic solvent used include aliphatic hydrocarbons such as hexane, heptane, octane, decane, dodecane, and tetradodecane; alicyclic hydrocarbons such as methylcyclopentane, cyclohexane, methylcyclohexane, cyclooctane, and cyclododecane; Benzene, toluene,
Xylene, ethylbenzene, cumene, ethyltoluene,
Aromatic hydrocarbons such as trimethylbenzene and diisopropylbenzene; halogenated hydrocarbons such as chlorobenzene, bromobenzene, o-dichlorobenzene, carbon tetrachloride, carbon tetrabromide, chloroform, bromoform, trichloroethane, trichloroethylene, tetrachloroethane, tetrachloroethylene, etc. Is mentioned. These may be used alone or in combination of two or more.

The aqueous dispersion of the present invention is obtained by dispersing the chlorinated modified polyolefin obtained as described above in water. As a method for producing the aqueous dispersion of the present invention by dispersing the chlorinated modified polyolefin in water, for example, a drum emulsification method in which the chlorinated modified polyolefin, water and a surfactant are mixed and emulsified at once; A pulverization method in which chlorinated modified polyolefin that has been pulverized in advance is added to water together with a surfactant to disperse the same; a chlorinated modified polyolefin dissolved in an organic solvent is mixed with the surfactant and water, and then the organic solvent is removed. Solvent-dispersing method; homomixer method of performing dispersion using a homomixer; phase inversion method; and the like, which is appropriately selected depending on the physical properties of the chlorinated modified polyolefin to be used.

Surfactants used include nonionic and anionic surfactants. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene sorbitan ester, and polyoxyethylene alkylamine ether.
Examples of the anionic surfactant include a fatty acid salt, a higher alcohol sulfate, sodium alkylbenzene sulfonate, a condensate of naphthalenesulfonic acid formalin, and polyoxyethylene alkyl ether sulfate. Particularly, sodium alkylbenzenesulfonic acid is preferable.

The amount of this surfactant used is usually 0.05 to the chlorinated modified polyolefin in that the dispersion state of the chlorinated modified polyolefin is good, and the adhesion of the obtained aqueous dispersion to the molded article is good. ~ 10% by weight is preferable, especially
0.1 to 7% by weight is preferred. Further, when the aqueous dispersion of the present invention is applied to the surface of a molded product by spray coating, uneven coating does not occur on the coated surface, the coating film adhesion does not vary, and the smoothness of the coated film after coating is applied. Is preferable, the amount of the surfactant is preferably 3 to 45% by weight based on the chlorinated modified polyolefin.

The blending ratio of the chlorinated modified polyolefin and water in the aqueous dispersion of the present invention is 5 to 70%.
In the range of 95 to 30 parts by weight of water to parts by weight,
It is appropriately selected. In particular, when spray-coating the aqueous dispersion of the present invention, coating unevenness is less likely to occur on the coated surface, variation in the adhesion of the coating film is less likely to occur, and the formed coating film layer does not become thicker. For example, when used as a primer, the content of the chlorinated modified polyolefin is preferably about 3 to 45% by weight from the viewpoint that the smoothness of the coating film after coating is improved.

In addition, a thickener, a basic substance, an antifoaming agent, and the like can be added to the aqueous dispersion of the present invention as needed. Further, in order to improve the wettability with the material to be applied, a small amount of an organic solvent may be added as necessary.

As the thickener, for example, ammonium alginate,
Mineral thickeners such as sodium alginate, bentonite clay; acrylic thickeners such as sodium polyacrylate, polyammonium acrylate, acrylic emulsion copolymer crosslinked acrylic emulsion copolymer;
Examples thereof include cellulose derivatives such as carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose, and hydroxyethylcellulose, and carboxymethylcellulose is particularly preferable.

Examples of the antifoaming agent include vegetable oils such as castor oil, soybean oil, and linseed oil; mineral oils such as spindle oil and liquid paraffin; fatty acids such as stearic acid and oleic acid; oleyl alcohol, polyoxyalkylene glycol, octyl alcohol, and the like. Alcohols; fatty acid esters such as ethylene glycol distearate and polyoxyethylene sorbitan monolaurate; phosphoric acid esters such as tributyl phosphate and sodium octyl phosphate; amides such as polyoxyalkylene amide; aluminum stearate and potassium oleate And metal soaps such as calcium stearate; silicons such as dimethyl silicon and polyether-modified silicon; amines such as diamylamine and polyoxypropylene alkylamine.

Further, in addition to the above, the aqueous dispersion of the present invention may further contain various stabilizers such as antioxidants, weather stabilizers, and heat inhibitors as required; coloring agents such as titanium oxide and organic pigments; carbon black and ferrite. May be included.

The aqueous dispersion of the present invention can be applied to the surface of a molded article made of polyolefin or another polymer, and used as a primer or the like for improving the adhesion of the paint to the surface. In particular, the aqueous dispersion of the present invention includes, for example, polyolefins such as high pressure polyethylene, medium / low pressure polyethylene, polypropylene, poly-4-methyl 1-pentene, poly-1-butene, and polystyrene; ethylene-propylene copolymers; It can be suitably used for molded articles made of olefin copolymers such as ethylene / butene copolymer and propylene / butene copolymer.

Further, the aqueous dispersion of the present invention, besides the above-mentioned polyolefin and its copolymer, comprises a molded article composed of polypropylene and synthetic rubber, a polyamide resin, an unsaturated polyester resin, a polybutylene terephthalate resin, a polycarbonate resin and the like. It can be used for molded articles, for example, molded articles such as bumpers for automobiles, and also for surface treatment of steel sheets, steel sheets for electrodeposition treatment, and the like. In addition, a primer, a primer, an adhesive or the like containing polyurethane resin, a fatty acid-modified polyester resin, an oil-free polyester resin, an melamine resin, an epoxy resin, etc. as a main component is applied to the surface, and the paint or the like adheres to the surface. While improving
It is also used to form a coating film having excellent clarity and low-temperature impact properties.

Further, the molded article to which the aqueous dispersion of the present invention is applied, the above-mentioned various polymers or resins are prepared by any of known molding methods such as injection molding, compression molding, hollow molding, extrusion molding, and rotational molding. It may be formed.

The aqueous dispersion of the present invention is a molded article to which it is applied, talc, zinc white, glass fiber, titanium white, inorganic fillers such as magnesium sulfate, pigments and the like are blended, especially for coating films. A primer coating film having good adhesion can be formed.

Further, the molded article to which the aqueous dispersion of the present invention is applied may contain various stabilizers, ultraviolet absorbers, hydrochloric acid absorbers and the like in addition to the above.

As a preferably used stabilizer, for example, 2,6-
Di-tert-butyl-4-methylphenol, tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate)] methane, metaoctadecyl-3-
(4'-Hydroxy-3,5-di-t-butylphenyl) propionate, 2,2'-methylenebis (4-methyl-6
-T-butylphenol), 4,4'-butylidenebis (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,
Phenolic stabilizers such as 5-tris (2-methyl-4-hydroxy-5-t-butylphenol) butane; sulfur-based stabilizers such as dilaurylthiodipropionate and distearylthiodipropionate; tridecyl phosphite And phosphorus-based stabilizers such as trinonylphenyl phosphite.

Further, as the ultraviolet absorber used, for example, 2
-Hydroxy-4-octoxybenzophenone, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate, paraoctylphenyl salicylate and the like.

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

As a method for applying the aqueous dispersion of the present invention to the surface of a molded article, spray coating is suitable. For example, the aqueous dispersion is sprayed on the surface of the molded article by a spray gun. The coating on the molded article may be performed at room temperature. After the coating, the coating is dried by an appropriate method such as natural drying or forced drying by heating to form a coating film.

As described above, after applying the aqueous dispersion of the present invention to the surface of a molded article and drying, the surface of the molded article is subjected to electrostatic coating,
The coating can be applied by a method such as spray coating or brush coating. The application of the paint may be performed by a method of applying an undercoat and then applying an overcoat. After applying the paint, the coating film is cured according to an ordinary method of heating with a nichrome wire, infrared ray, high frequency or the like, and a molded article having a desired coating film on the surface can be obtained. How to cure the coating film,
It is appropriately selected depending on the material and shape of the molded product, the properties of the paint used, and the like.

Further, the aqueous dispersion of the present invention, by utilizing the characteristics of excellent adhesiveness, peel strength and water resistance, in addition to the use as a primer of the molded article, can be applied to a wide range of applications, for example, Needless to say, the present invention can also be applied to uses such as additives for adhesives and paints.

<Examples> Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples of the present invention, but the present invention is not limited to these Examples. In the following, the physical properties of the coating film were evaluated according to the following methods.

Cross-cut test According to the cross-cut test method described in JIS K5400, a test piece with a cross-cut is prepared, and a cellotape (trade name, manufactured by Nichiban Co., Ltd.) is stuck on the cross-cut of the test piece. After that, this was quickly pulled in the direction of 90 ° to be peeled off, and the number of grids which were not peeled out of the grid 100 was counted, and was used as an index of adhesion.

Peel strength Prepare a coating film on the substrate, cut a 1cm width until the blade reaches the substrate with a cutter blade, after peeling the end,
The peel strength was measured by pulling the edge of the peeled coating film at a speed of 50 mm / min in a direction of 180 ° until the coating film was peeled.

After immersing the test piece in water at 40 ° C. for 240 hours, the test piece is subjected to a grid test to evaluate the adhesion.

(Example 1) 250 parts by weight of polypropylene (intrinsic viscosity "η": 2.0 dl / g) and 500 parts by weight of toluene were charged into a 1.5-capacity reaction vessel equipped with a stirrer, and heated to 150 ° C while stirring.
Temperature. 2-hydroxypropyl acrylate 25
Parts by weight and 6.5 parts by weight of di-t-butyl peroxide were separately added dropwise over 5 hours.
The mixture was reacted at 150 ° C. for 2 hours with stirring to obtain a graft-modified polypropylene.

When the content of 2-hydroxypropyl acrylate in the obtained graft-modified polypropylene was measured,
1.6% by weight. The intrinsic viscosity [η] was 0.7 dl / g when measured in decalin at 135 ° C.

The graft-modified polypropylene obtained above is completely dissolved by heating to 110 ° C. in a chlorobenzene solvent,
While maintaining the temperature, the light was completely shut off, chlorine gas was supplied, and the reaction was performed for about 2 hours. A large excess of methanol was added to the obtained reaction mixture to precipitate a reaction product, which was separated, washed repeatedly with methanol, and dried under reduced pressure to obtain a graft-modified / chlorinated polypropylene.

When the chlorine content of the obtained graft-modified / chlorinated polypropylene was measured, it was 30% by weight.

Next, the obtained graft-modified / chlorinated polypropylene was dissolved in toluene to prepare a solution having a polymer concentration of 125 g / 500 g of this polymer solution, 500 g of distilled water and sodium dodecylbenzenesulfonate (manufactured by Kao Corporation, 1.44 g of Perex F-25) were mixed by stirring at 10,000 rpm for 15 minutes. Subsequently, 0.72 g of polyacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd., Hibiswako 304) was added and stirred,
The mixture was mixed to obtain an emulsion. The toluene in the obtained emulsion was distilled off under reduced pressure using an evaporator to obtain an aqueous dispersion having a polymer concentration of 20% by weight.

This aqueous dispersion was spray-coated on a square plate made of polypropylene (X440, manufactured by Mitsui Petrochemical Industries, Ltd.) washed with 1,1,1-trichloroethane vapor at 200 g / m ² .

After this square plate was dried by heating at 100 ° C. for 30 minutes in an air oven, it was subjected to a grid test and an evaluation of water resistance. Table 1 shows the results.

(Example 2) As in Example 1, after applying an aqueous dispersion to a polypropylene square plate, a urethane-based paint (R-271, manufactured by Nippon Bee Chemical Co., Ltd.) was further dried to a dry film thickness of 60 µm. Was overcoated. Next, baking was performed in an oven at 100 ° C. for 30 minutes to obtain a coating film sample.

The obtained sample was subjected to a grid test, measurement of peel strength, and evaluation of water resistance. Table 1 shows the results.

(Example 3) Coating was performed in the same manner as in Example 2 except that a square plate made of poly 4-methylpentene-1 (manufactured by Mitsui Petrochemical Industries, Ltd., TPX) was used instead of the polypropylene square plate. The obtained coating film sample was subjected to a grid test, a measurement of peel strength, and an evaluation of water resistance. Table 1 shows the results.

Example 4 Instead of 2-hydroxypropyl acrylate, 2
A graft-modified polypropylene was produced in the same manner as in Example 1 except that -hydroxyethyl methacrylate was used. When the content of 2-hydroxyethyl methacrylate in the obtained graft-modified polypropylene was measured, it was 1.1% by weight. The intrinsic viscosity [η] measured in decalin at 135 ° C. was 0.7 dl / g. After chlorinating this graft-modified polypropylene in the same manner as in Example 1, an aqueous dispersion was prepared. A sample was prepared in the same manner as in Example 2, and a cross-cut test, measurement of peel strength and evaluation of water resistance were performed. Was served. Table 1 shows the results.

(Example 5) 3 kg of the same polypropylene as that used in Example 1,
120 g of 2-hydroxypropyl acrylate and 2,5-
12 g of dimethyl-di (t-butylperoxy) hexane
Was mixed in advance with a Henschel mixer, and then supplied to a twin-screw extruder (PCM = 45, manufactured by Ikegai Iron Works), and heated at a heating temperature of 210
The mixture was extruded while being kneaded at a temperature of 260 ° C. and a rotational speed of 260 rpm, and reacted to obtain a graft-modified polypropylene. When the content of 2-hydroxypropyl acrylate in the obtained graft-modified polypropylene was measured, it was 1.5% by weight. The intrinsic viscosity measured at 135 ° C. in decalin was 0.5 dl / g. After chlorinating this graft-modified polypropylene in the same manner as in Example 1, an aqueous dispersion was prepared, and a sample was prepared in the same manner as in Example 2 for cross-cut test, measurement of peel strength, and evaluation of water resistance. Provided. Table 1 shows the results.

(Comparative Example 1) A top coat was applied in the same manner as in Example 2 without applying an aqueous dispersion to the same polypropylene square plate as that used in Example 1 to prepare a sample. The test, measurement of peel strength, and evaluation of water resistance were performed.
Table 1 shows the results.

(Comparative Example 2) Except not using 2-hydroxypropyl acrylate and graft copolymerizing it with polypropylene,
An aqueous dispersion was prepared in the same manner as in Example 1, and a sample was prepared using the aqueous dispersion in the same manner as in Example 2.
It was used for measurement of peel strength and evaluation of water resistance. Table 1 shows the results.

Peel strength: g / cm Note "-" in the table indicates that the measurement was not performed.

Crosscut: The number of crosscuts that were not peeled per 100 crosscuts <Effect of the Invention> The aqueous dispersion of the present invention is a resin molded product, for example, a polyolefin such as polypropylene, a synthetic rubber, an unsaturated polyester, an epoxy resin, Since it has excellent adhesion to molded products made of various resins such as polyurethane resin or these composite resins, it is necessary to apply it to the surface of these molded products to obtain a coating film with sufficient peel strength and adhesion. It is suitable as a primer because it is an aqueous system containing no organic solvent and can maintain a good working environment.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-139903 (JP, A) JP-A-1-256556 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08J 3/03 C08F 255/00-255/10

Claims (2)

(57) [Claims] 1. A polyolefin having propylene and / or 1-butene as a main component and an intrinsic viscosity [η] of 1 dl / g or more is graft-copolymerized with an α, β-vinyl monomer having a hydroxyl group. Modified polymer with intrinsic viscosity
An aqueous dispersion comprising a chlorinated modified polyolefin having a chlorine content of 10 to 40% by weight, which is obtained by further chlorinating a modified polymer of 0.4 to 1 dl / g, in water. 2. The α, β-vinyl monomer having a hydroxyl group is at least one selected from mono (meth) acrylates of monohydric alcohols and mono (meth) acrylates of polyhydric alcohols. The aqueous dispersion according to claim 1.