JP5576164B2 - Water-based paint composition and method for coating plastic molded product - Google Patents

Description

  The present invention relates to a water-based coating composition excellent in adhesion to polyolefin materials, and further excellent in water resistance, oil resistance, and smoothness, and a method for coating a plastic molded article comprising a polyolefin material and the like.

  Interior parts such as automotive instrument panels, center consoles, dashboards, and door trims are made of various materials such as polypropylene, polycarbonate, and ABS as plastic materials. In recent years, polyolefin materials, Among them, especially polypropylene materials are increasing. Since the polypropylene material is generally inferior in the adhesion of the coating film, the surface of the material is activated by plasma treatment as a pretreatment for ensuring adhesion. However, this process complicates the coating process and increases the cost. In addition, it is an urgent task to make paints water-based from the viewpoint of reducing organic solvents for environmental conservation. Under such circumstances, an aqueous coating composition that can form a coating film excellent in adhesion to a polypropylene material without pretreatment is desired. In particular, in automobile interior parts in which polypropylene materials are frequently used, the coating film is required to have excellent oil resistance and water resistance. Then, the aqueous coating composition using the polyolefin resin excellent in the adhesiveness to a polypropylene raw material or a chlorinated polyolefin resin has been examined. For example, Patent Document 1 discloses an aqueous coating composition comprising an aqueous modified polyolefin resin modified with an α, β-unsaturated dicarboxylic acid or an acid anhydride thereof, an aqueous acrylic resin, and an aqueous urethane resin. It is described that the acrylic resin may contain a functional group such as a ketonic carbonyl group capable of reacting with a crosslinking agent. Patent Document 2 proposes an aqueous coating composition in which a chlorinated polyolefin resin emulsion and a pure acrylic resin emulsion are blended at a specific ratio. Among them, it is described that a pure acrylic resin is a component that enhances oil resistance. Patent Document 3 discloses an aqueous resin composition obtained by emulsifying an organic solvent solution of chlorinated polyolefin in the presence of a surfactant and polymerizing a vinyl monomer in the emulsion. Describes that it has excellent adhesion and water resistance because it contains less surfactant than in the past. Patent Document 4 discloses an aqueous resin composition obtained by adding a neutralizing agent and water to a carboxyl group-containing chlorinated propylene-based random copolymer to make it water-based and then emulsion-polymerizing a vinyl-based monomer. Yes. It is described that the water resistance and oil resistance of the coating film are improved by emulsion polymerization of the vinyl monomer.

  The aqueous resin compositions disclosed in the above-mentioned Patent Documents 1 to 4 show that the polyolefin or chlorinated polyolefin has excellent affinity and adhesion to the polyolefin base material, and further a polymer of other vinyl monomers. (Vinyl resin), acrylic resin, etc. are used together to impart cross-linking reactivity and improve various performances of the coating film. However, since the aqueous resin compositions disclosed in Patent Documents 1 to 4 are hardly compatible with the polyolefin resin or chlorinated polyolefin resin and the vinyl resin or acrylic resin contained in the composition, the inside of the coating film or the surface layer Phase separation, resulting in a problem that the smoothness, adhesion, oil resistance and water resistance of the coating film may decrease.

JP-A-6-336568 JP 2001-2777 A JP-A-7-300570 JP 2004-91559 A

  An object of the present invention is to provide an aqueous coating composition capable of forming a coating film excellent in smoothness, adhesion, oil resistance and water resistance to a polyolefin material, and a method for coating a plastic molded product such as polyolefin. .

  As a result of intensive studies to solve the above problems, the inventors of the present invention have a water-based coating composition containing a modified polyolefin resin and a hydrazine derivative characterized by containing a carboxyl group and a ketonic carbonyl group in the side chain. It has been found that the above problems can be solved by using a product, and the present invention has been completed.

That is, the present invention comprises the following items.
Item 1. A modified polyolefin resin containing a carboxyl group and a ketonic carbonyl group in the side chain, wherein the modified polyolefin resin has at least one active hydrogen bonded to nitrogen and an amine compound (A1) and diacetone Modified polyolefin which is obtained by ring-opening addition reaction between compound (A) which is obtained by Michael addition reaction with acrylamide or vinyl ketones (A2) and acid anhydride group-containing polyolefin resin (B) Resin .
Item 2 . Item 11. A modified polyolefin resin aqueous dispersion in which the modified polyolefin resin according to Item 1 is dispersed in a medium containing water.
Item 3 . Item 5. An aqueous coating composition containing the modified polyolefin resin aqueous dispersion according to Item 2 and a hydrazine derivative.
Item 4 . Item 4. A method for coating a plastic molded product, comprising applying the water-based paint composition according to Item 3 to a plastic molded product that may be surface-treated.
Item 5 . Item 5. A coated article obtained by the coating method according to Item 4 .

  The modified polyolefin resin, which contains a carboxyl group and a ketonic carbonyl group in the side chain in the present invention, has a highly polar carboxyl group, a ketonic carbonyl group, and a highly polar group such as an amide group or an ester group. Have. In addition, since the aqueous coating composition in the present invention contains the modified polyolefin resin and a hydrazine derivative as a crosslinking agent, the coating obtained from the aqueous coating composition is crosslinked by a reaction between a ketonic carbonyl group and a hydrazine derivative. It has a structure. Therefore, the film obtained from the water-based coating composition in the present invention has high cohesive force due to the above-described highly polar group and a crosslinked structure, and thus has excellent water resistance and oil resistance. Furthermore, since the modified polyolefin resin has a highly polar group, it is superior in compatibility with a resin having a relatively high polarity compared to a polyolefin resin such as an acrylic resin or a urethane resin. , Oil resistance and water resistance can be suppressed.

  The present invention relates to a modified polyolefin resin characterized by containing a carboxyl group and a ketonic carbonyl group in the side chain, and an aqueous coating composition containing the modified polyolefin resin. The modified polyolefin resin is formed by, for example, opening a compound (A) having a reactive group capable of undergoing a ring-opening addition reaction with an acid anhydride group and a ketonic carbonyl group and an acid anhydride group-containing polyolefin resin (B). It can be obtained by a cycloaddition reaction.

(Compound A)
The compound (A) can be obtained, for example, by a Michael addition reaction between an amine compound (A1) having one or more active hydrogen bonded to nitrogen and diacetone acrylamide or vinyl ketones (A2). The compound (A) has a reactive group capable of undergoing a ring-opening addition reaction with the acid anhydride group of the acid anhydride group-containing polyolefin resin (B). For example, such a reactive group includes , Hydroxyl groups, primary amino groups and secondary amino groups.

  Specific examples of the amine compound (A1) having at least one active hydrogen bonded to nitrogen are methylamine, ethylamine, propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, t-butylamine, hexylamine, 2 -Methoxyethylamine, 2-ethoxyethylamine, 3-methoxypropylamine, 3-methylthiopropylamine, ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, N-methylethylenediamine, N-ethylethylenediamine, N, N-dimethylethylenediamine, An aliphatic compound having a carbon number of C1 to C16 which may contain a nitrogen atom, an oxygen atom or a sulfur atom such as allylamine; cyclopentylamine, cyclohexylamine, cycloheptyl Minor, cyclooctylamine, aminomethylcyclohexane, 4-methylcyclohexylamine, 1-cyclohexylethylamine, 3,3,5-trimethylcyclohexylamine, isophoronediamine, bisaminomethylcyclohexane, nitrogen atom, oxygen atom, sulfur atom An alicyclic compound having a carbon number of C1 to C16, which may contain: benzylamine, phenethylamine, 4-methylbenzylamine, N-aminopropylaniline, 2-amino-1,2-diphenylethanol, 9-amino Aromatic compounds having a carbon number of C1 to C16 which may contain nitrogen, oxygen and sulfur atoms such as fluorene, benzhydrylamine, xylylenediamine, phenylenediamine, diaminodiphenylmethane and N-benzylethylenediamine Piperazine, N-aminopropylpiperazine, N-aminoethylpiperidine, N-aminopropylpiperidine, 2-aminomethylpiperidine, 4-aminomethylpiperidine, furfurylamine, tetrahydrofurfurylamine, 3aminopyrrolidine, 3- (methylamino) pyrrolidine Carbon number of C1-C16 which may contain nitrogen atom, oxygen atom, sulfur atom such as 5-methylfurfurylamine, 2- (furfurylthio) ethylamine, 2-picolylamine, 3-picolylamine, 4-picolylamine, etc. 2-hydroxyethylamine, methyl (2-hydroxyethyl) amine, 1-amino-2-propanol, 3-amino-1-propanol, 2-amino-1-propanol, 1-amino-2 -Propanol, Dietano 1 or more hydroxyl groups such as uramine, 3-amino-1,2-propanediol, 2- (2-aminoethoxy) ethanol, N- (2-hydroxyethyl) ethylenediamine, 2-amino-1,3-propanediol And the like.

  For example, when n-butylamine which is an aliphatic compound is selected as the amine compound (A1), the Michael addition reaction with diacetone acrylamide is represented by the following reaction formula (1) and has one secondary amino group. A compound (A) having one ketonic carbonyl group is obtained.

  Further, when a compound having one or more hydroxyl groups is selected as the amine compound (A1), the hydroxyl group does not participate in the Michael addition reaction due to the Michael addition reaction with diacetone acrylamide or vinyl ketones (A2). A compound (A) having more than one can be obtained.

  The Michael addition reaction in the present invention is usually carried out in the range of 0 to 200 ° C., preferably in the range of 50 to 120 ° C., so that a desired reaction product can be obtained in a short time and unintended side reaction. It is preferable from the point which can suppress.

  In the present invention, the molar ratio of the amine compound (A1) to diacetone acrylamide or vinyl ketones (A2) is in the range of 0.8 to 5.0, more preferably in the range of 0.9 to 2.2. From the viewpoint of reducing unreacted diacetone acrylamide or vinyl ketones, or suppressing the generation of a compound having no active hydrogen that reacts with an acid anhydride group-containing polyolefin resin. preferable. The reaction can be carried out in the presence of water or an organic solvent. When using an organic solvent, the kind is not specifically limited, However, Well-known organic solvents, such as ester type, ether type, aliphatic type, and aromatic type, can be used. The concentration of the reaction component when using water or an organic solvent is preferably 20% or more, more preferably 50% or more. If it is less dilute, the reaction may not proceed easily. Moreover, although reaction time changes with kinds of amine compound to be used, it can be normally performed in 30 minutes-5 hours.

  The above vinyl ketones are compounds having a structure in which an acyl group is bonded to one of carbon atoms forming a carbon-carbon double bond, such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, butyl vinyl ketone, and phenyl vinyl ketone. Etc.

  A catalyst can also be used when performing the Michael addition reaction. Examples of the catalyst include metal alkoxides such as sodium methoxide, sodium ethoxide, and magnesium ethoxide; metal phenoxides such as sodium phenoxide; metal carbochelates such as sodium benzoate and potassium benzoate; triethylamine, triethylenediamine, N, N -Diethylaniline, N, N-dimethylaniline, N, N-dimethylbenzylamine, N-methylmorpholine, N-ethylmorpholine, N, N'-dimethylpiperazine, pyridine, picoline, 1,8-diazabicyclo (5 , 4, 0) tertiary amines such as undecene-7; tetraethylammonium bromide, tetrabutylammonium bromide, benzyltriethylammonium chloride, trioctylmethylammonium chloride, cetyltrimethylammonium bromide, Quaternary ammonium salts such as tetrabutylammonium iodide, dodecyltrimethylammonium iodide, benzyldimethyltetradecylammonium acetate; quaternary phosphonium salts such as tetraphenylphosphonium chloride, triphenylmethylphosphonium chloride, tetramethylphosphonium bromide; Methylimidazole, 2-ethylimidazole, 2-methyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2 Examples include basic compounds such as imidazole compounds such as -phenyl-4,5-dihydroxymethylimidazole and 1-azine-2-methylimidazole. One type or two or more types of catalysts can be used. When using a catalyst, the usage-amount is 10 mol% or less with respect to the usage-amount of an amine compound (A1).

  The reaction product obtained by the Michael addition reaction contains an unreacted amine compound or a compound in which a ketonic carbonyl group is ketiminated in addition to the compound (A) having a ketonic carbonyl group. There is. When the reaction product contains a large amount of unreacted amine compound, in the reaction of the compound (A) with the acid anhydride group-containing polyolefin resin (B) described later, the ketonic property to the modified polyolefin resin to be generated Since introduction efficiency of the carbonyl group may be lowered, it is preferably removed. The removal can be performed by distillation or azeotropy with water and / or an organic solvent under normal or reduced pressure conditions. As the organic solvent, the solvent used in the Michael addition reaction can be used, but when a solvent that reacts with an acid anhydride group such as water or alcohol is used in the Michael addition reaction, the acid anhydride group is used. It is preferable to remove by a known method such as distillation under normal pressure or reduced pressure before the reaction with the containing polyolefin resin (B).

  Moreover, when the reaction product obtained by the Michael addition reaction contains a large amount of ketiminated compounds, the following problems may occur. 1) In the aqueous dispersion of the modified polyolefin resin, the ketiminated portion is hydrolyzed to become a volatile organic compound. 2) Gelation may occur in the reaction between the reaction product and the anhydride group-containing polyolefin resin (B). Accordingly, in the amine addition (A1) and Michael addition reaction, water is added to a mixture of diacetone acrylamide or vinyl ketones (A2) to perform the Michael addition reaction, or excess water is added to the mixture obtained by the Michael addition reaction. Is added to hydrolyze the ketiminated portion of the ketiminated compound to obtain a Michael addition reaction product containing a ketonic carbonyl group, thereby solving the above problem. The amine compound produced by this hydrolysis can be removed in the same manner as the unreacted amine compound.

  The removal of the unreacted amine compound and the removal of the amine compound formed by hydrolyzing the ketiminated compound can be performed simultaneously with the Michael addition reaction or after the completion of the Michael addition reaction.

In diacetone acrylamide, a peak derived from a CH ₂ ═CH double bond is observed at 6.19 to 6.23 ppm in 1H-NMR measurement using a deuterated chloroform solvent. In the measurement of 1H-NMR using the deuterated chloroform solvent of the reaction product, no peak is observed at 6.19 to 6.23 ppm. Therefore, in the present invention, the Michael addition reaction is traced by the NMR measurement. Can do.

(Acid anhydride group-containing polyolefin resin (B))
Examples of the acid anhydride group-containing polyolefin resin (B) used in the present invention include those obtained by modifying a polyolefin resin with an acid anhydride group-containing unsaturated compound in a known method and those chlorinated. The polyolefin resin is, for example, a polyolefin obtained by polymerizing one or more selected from olefins having 2 to 10 carbon atoms such as ethylene, propylene, butylene and hexene by a known method, the above olefins and dienes. Copolymer and its hydrogenated product, polybutadiene and its hydrogenated product, polyisoprene and its hydrogenated product, styrene / butadiene copolymer and its hydrogenated product, styrene / isoprene copolymer and its hydrogenated product, etc. And a hydrogenated product thereof, a petroleum resin and a hydrogenated product thereof, a natural rubber and a hydrogenated product thereof, and the like. The acid anhydride group-containing polyolefin resin in the present invention is obtained by modifying the above-described polyolefin resin according to a known method using an acid anhydride group-containing unsaturated compound such as maleic anhydride, itaconic anhydride, citraconic anhydride, or aconitic anhydride. Can be obtained. Those modified with maleic anhydride are particularly preferred. The amount of modification by the acid anhydride group-containing unsaturated compound is 1 to 20% by mass, preferably 1 to 10% by mass with respect to the solid content mass of the polyolefin resin.

  The acid anhydride group-containing polyolefin resin may be further chlorinated. The chlorination reaction may be performed at any time before, after, or simultaneously with the modification of the polyolefin resin with the acid anhydride group-containing unsaturated compound. The chlorination reaction can be performed, for example, by blowing chlorine gas into an organic solvent solution or dispersion of a polyolefin resin or its anhydride group-containing polyolefin resin, and the reaction temperature can be 50 to 120 ° C. The chlorine content in the chlorinated product (solid content) of the polyolefin resin can be changed according to the physical properties desired for the chlorinated product of the polyolefin resin. It is desirable that the amount be 35% by mass or less, particularly 10 to 30% by mass, and more particularly 12 to 25% by mass based on the weight of the chlorinated resin.

  The polyolefin resin used for the acid anhydride group-containing polyolefin resin (B) is particularly preferably a propylene polymer or copolymer, and the mass fraction of propylene in the polyolefin resin is 0.5. It is suitable from the point of the adhesiveness of a formed coating film that it is -1.0, Preferably it is 0.7-0.99.

(Modified polyolefin resin)
The modified polyolefin resin in the present invention contains a compound (A) having a reactive group capable of ring-opening addition reaction with the acid anhydride group obtained by the Michael addition reaction and a ketonic carbonyl group and an acid anhydride group. It can be obtained by a ring-opening addition reaction with the polyolefin resin (B), and the reaction can be carried out in the presence of an organic solvent. Although it does not specifically limit as an organic solvent, Well-known solvents, such as ester type and ether type, can be used. The concentration of the above reaction components is preferably in the range of 50 to 90% by mass from the viewpoint that the reaction rate and the amount of solvent remaining when the obtained resin is dispersed with water can be reduced. Preferably it exists in the range of 55-80 mass%. Moreover, it is preferable to make reaction temperature into the range of 25-120 degreeC from the point of reaction rate or a viscosity, More preferably, it exists in the range of 40-100 degreeC.

  In the ring-opening addition reaction between the above compound (A) and the acid anhydride group-containing polyolefin resin (B), when the compound (A) has a hydroxyl group, a modification having an ester group, a carboxyl group, or a ketonic carbonyl group When a polyolefin resin is produced and the compound (A) has a primary or secondary amino group, a modified polyolefin resin having an amide group, a carboxyl group, and a ketonic carbonyl group is produced.

  The weight average molecular weight of the modified polyolefin resin of the present invention is preferably in the range of 10,000 to 500,000, and more preferably in the range of 30,000 to 300,000. When the weight average molecular weight is larger than this range, the viscosity of the modified polyolefin resin becomes high, the production is difficult, and the finishing property when made into a paint may be lowered. Moreover, when it is small, sufficient water resistance may not be obtained.

  In this specification, the weight average molecular weight is the retention time (retention capacity) of a standard polystyrene having a known molecular weight measured under the same conditions as the retention time (retention capacity) measured using gel permeation chromatography (GPC). Is a value obtained by converting to a molecular weight of polystyrene. Specifically, “HLC8120GPC” (trade name, manufactured by Tosoh Corporation) is used as a gel permeation chromatograph, and “TSKgel G-4000HXL”, “TSKgel G-3000HXL”, “TSKgel G-2500HXL” are used as columns. ”And“ TSKgel G-2000HXL ”(trade names, all manufactured by Tosoh Corporation), a differential refractometer is used as a detector, mobile phase: tetrahydrofuran, measurement temperature: 40 ° C., flow rate: It can be measured under the condition of 1 mL / min.

(Modified polyolefin resin aqueous dispersion)
The aqueous coating composition of the present invention includes a modified polyolefin resin aqueous dispersion in which the modified polyolefin resin is dispersed in a medium containing water.

  Examples of the method for obtaining the aqueous dispersion of the modified polyolefin resin include a method in which the carboxyl group contained in the modified polyolefin resin is neutralized with a basic compound to form fine particles in a medium containing water. As the basic compound, known compounds can be used, and examples thereof include metal hydroxides, amine compounds, ammonia, and the like, and they are easily volatilized from the viewpoint of acid resistance and water resistance of the resulting coating film. Neutralization with an amine compound having 6 or less carbon atoms or ammonia can be suitably performed. Examples of the amines include triethylamine, triethanolamine, dimethylethanolamine, diethylethanolamine, morpholine and the like. The neutralization equivalent with the basic compound is more preferably 10 to 150 mol% with respect to the carboxylic acid in the resin, from the viewpoint of the storage stability of the modified polyolefin resin aqueous dispersion of the present invention and the water resistance of the resulting coating film. Is preferably in the range of 50 to 120 mol%.

  In addition to the above, the method for obtaining the modified polyolefin resin aqueous dispersion is, for example, a method in which the modified polyolefin resin is microparticulated in a medium containing water using an emulsifier, or the carboxyl group contained in the modified polyolefin resin is neutralized. Furthermore, the method etc. which are microparticulated in the medium containing water using an emulsifier can be mentioned.

  Although it does not specifically limit as an emulsifier, For example, an anionic emulsifier, a cationic emulsifier, a nonionic emulsifier, an amphoteric emulsifier, a reactive emulsifier etc. can be used.

  Examples of anionic emulsifiers include alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate and sodium dodecyl sulfate, fatty acid salts, rosinates, alkyl sulfates, alkyl sulfosuccinates, α-olefin sulfonates, and alkyl naphthalene sulfonates. , Polyoxyethylene alkyl (aryl) sulfate ester salts, etc .; as a cationic emulsifier, quaternary ammonium salts such as lauryl trialkyl ammonium salt, stearyl trialkyl ammonium salt, trialkyl benzyl ammonium salt, primary to tertiary Secondary amine salt, laurylpyridinium salt, benzalkonium salt, benzethonium salt, laurylamine acetate, etc .; nonionic emulsifiers include polyoxyethylene alkyl ether, polyoxyethylene Alkylphenol ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan alkyl esters and the like; amphoteric emulsifiers such as carboxybetaine type, sulfobetaine type, aminocarboxylic acid type, imidazoline derivative type and the like; Eleminol JS-2 (manufactured by Sanyo Chemical Industries), Eleminol RS-30 (manufactured by Sanyo Chemical Industries), Latemul S-180A (manufactured by Kao), Aqualon HS-05 (manufactured by Daiichi Kogyo Seiyaku), Aqualon RN-10 (1st Kogyo Seiyaku Co., Ltd.), Adekaria soap SE-10N (Asahi Denka Co., Ltd.) and the like. Moreover, the well-known polymeric emulsifier whose number average molecular weight is 300 or more can also be mentioned.

  In the present invention, the amount of the emulsifier used is 50 masses with respect to 100 parts by mass of the modified polyolefin resin from the viewpoint of the stability of the aqueous dispersion and the water resistance when used as a coating film forming component of the coating composition. The amount is preferably at most 30 parts by mass, more preferably at most 30 parts by mass.

  It is also possible to impart a hydrophilic nonionic group to the modified polyolefin resin by reaction and obtain an aqueous dispersion of the modified polyolefin resin using this.

  Examples of the method for imparting the nonionic group include a hydrophilic polyoxyalkylene compound having an active hydrogen group capable of reacting with an acid anhydride group, and a nonionic hydrophilic group-containing vinyl monomer polymer having an active hydrogen group. Can be imparted by reacting with an acid anhydride group of the acid anhydride group-containing polyolefin resin.

  The concentration of the modified polyolefin resin aqueous dispersion of the present invention is preferably in the range of 15 to 50% by mass, more preferably in the range of 20 to 45% by mass as a solid content from the viewpoint of stability and viscosity. .

(Water-based paint composition)
The aqueous coating composition of the present invention contains a hydrazine derivative capable of reacting with the ketonic carbonyl group of the modified polyolefin resin aqueous dispersion as a crosslinking agent. As the hydrazine derivative, a compound having two or more hydrazide groups and / or semicarbazide groups in one molecule can be preferably used. For example, saturated fatty acid dihydrazides having 2 to 18 carbon atoms such as succinic acid dihydrazide, malonic acid dihydrazide, glutaric acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, etc .; maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide Monoolefinically unsaturated dicarboxylic acid dihydrazide, phthalic acid, terephthalic acid or isophthalic acid dihydrazide, and pyromellitic acid dihydrazide, trihydrazide or tetrahydrazide; nitrilotrihydrazide, citric acid trihydrazide, 1,2,4-benzenetrihydrazide , Ethylenediaminetetraacetic acid tetrahydrazide, 1,4,5,8-naphthoic acid tetrahydrazide, two or more carboxylic acid lower alkyl ester groups in one molecule. Polyhydrazide obtained by reacting a low polymer having hydrazine or hydrazine hydrate (hydrazine hydride) (see Japanese Patent Publication No. 52-22878), polyhydrazide compounds such as carbonic dihydrazide; diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate; Polysemicarbazide compound obtained by reacting polyisocyanate compound derived therefrom with hydrazine or monoalkyl-substituted hydrazine, polyhydrazide obtained by reacting diisocyanate compound or polyhydrazide compound exemplified above with polyisocyanate compound containing diisocyanate Obtained from the reaction of a compound, a polyisocyanate compound and a polyether or polyol having active hydrogen such as polyethylene glycol monoalkyl ethers. A polysemicarbazide compound obtained by reacting an isocyanate group in the modified polyisocyanate compound with hydrazine or a monoalkyl-substituted hydrazine, and a polyhydrazide obtained by reacting the above-exemplified dihydrazide or polyhydrazide with the isocyanate group of the modified polyisocyanate compound Examples thereof include compounds, and these can be used alone or mixed together as necessary.

  In general, the hydrazine derivative preferably has a total of hydrazide group and semicarbazide group contained in the hydrazine derivative within a range of 0.01 to 2 mol with respect to 1 mol of the ketonic carbonyl group of the modified polyolefin resin. Preferably it is in the range of 0.1 to 1.5 mol from the viewpoint of low temperature curability.

  The water-based coating composition of the present invention may further comprise a water-based resin, a color pigment, a rust preventive pigment, a rheology control agent, a pigment dispersant, an anti-settling agent, a curing catalyst, an antifoaming agent, an antioxidant, and an ultraviolet absorber as necessary. Various additives such as additives, extender pigments and the like may be appropriately blended and mixed and dispersed. Since the modified polyolefin resin in the present invention has a highly polar group such as an ester group or an amide group, a carboxyl group and a carbonyl group, the compatibility with other highly polar aqueous resins is better than conventional polyolefin resins. It is possible to use the above aqueous resin together. Examples of the aqueous resin include those dispersed in an aqueous medium such as an acrylic resin emulsion, a polyester emulsion, an epoxy resin emulsion, and a polyurethane emulsion, or dissolved in an aqueous medium such as an acrylic resin aqueous solution, a polyester aqueous solution, an epoxy resin aqueous solution, and a polyurethane aqueous solution. Known ones can be mentioned.

(Coating method and article)
The aqueous coating composition of the present invention obtained as described above can be applied to plastic molded articles. As plastic molded products, it is used for automotive interior parts such as instrument panels (instrument panels), door trims, console panels, center clusters, switch panels, meter hoods, shift knobs, handles, etc., and outer panels of home appliances, etc. Examples of such plastic molded products include those obtained by subjecting these plastic molded materials to surface treatment, undercoating and intermediate coating, and composite materials obtained by combining these materials. As the material of the plastic molded product, for example, polyolefins obtained by (co) polymerizing one or more of olefins having 2 to 10 carbon atoms such as ethylene, propylene, butylene and hexene are particularly suitable. In addition, the composition of the present invention can be applied to polycarbonate, ABS resin, urethane resin, polyamide and the like.

  The coating of the composition of the present invention is usually performed using air spray, airless spray, dip coating, brush, or the like so that the dry film thickness is within a range of 5 to 50 μm, preferably 10 to 40 μm. Can be done. After the application of the composition, the resulting coated surface can be heated for about 20 to 40 minutes at a temperature of about 50 to about 140 ° C., preferably about 50 to about 100 ° C., if necessary.

  Next, an Example is given and this invention is demonstrated more concretely. Here, “parts” and “%” mean “parts by mass” and “% by mass”, respectively.

(Production Example 1)
Production of Michael addition reaction product 1 Air in a 1 L flask equipped with a stirrer, thermometer, condenser, nitrogen gas inlet was replaced with nitrogen, 338.4 g of diacetone acrylamide, deionized water 180.2 g and N-ethylethylenediamine 352.6 g were added and stirred, and the temperature was raised to 80 ° C. and maintained at 80 ° C. for 3 hours. Next, while reducing the pressure to about 100 mmHg, the temperature was maintained at 60 to 80 ° C. for 2 hours, and about 240 g of a mixture of water and unreacted N-ethylethylenediamine was removed azeotropically. Thereafter, 200 g of water was added and maintained at 80 ° C. for 1 hour, and then maintained at 60 to 80 ° C. for 1.5 hours while reducing the pressure to about 100 mmHg to remove azeotropically about 200 g of the mixture of water and N-ethylethylenediamine. Repeated twice. Thereafter, the pressure is reduced to about 10 mmHg and held at 60 to 80 ° C. for 1.5 hours, and the remaining water and N-ethylethylenediamine are removed to have two secondary amino groups, and a ketonic carbonyl group. Michael addition reaction product 1 having

  0.1 g of Michael addition reaction product 1 obtained in a 100 mL Erlenmeyer flask was weighed, and 30 mL of acetic acid was added and dissolved, and then an indicator (alphazulin G 0.3 g dissolved in glacial acetic acid 100 mL and thymol blue 1 0.2 mL of a solution obtained by dissolving 0.5 g in methanol) was added, and titrated with 0.1 N perchloric acid (acetic acid solution) until the solution changed from green to red. As a result, the amine value of Michael addition reaction product 1 was 426 mgKOH / g.

(Production Example 2)
Production of Michael addition reaction product 2 Air in a 2 L flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet was replaced with nitrogen, and 507.7 g of diacetone acrylamide, 270. water. 3 g and 438.8 g of butylamine were added and stirred, and the temperature was raised to 80 ° C. and maintained at 80 ° C. for 2 hours. Next, the pressure was reduced to about 100 mmHg and maintained at 60 to 80 ° C. for 1.5 hours, and about 430 g of a mixture of water and unreacted butylamine was removed azeotropically. After that, an operation for attaching a moisture determination receiver to the flask, adding 270 g of water, raising the temperature to 105 ° C., holding at 103 to 105 ° C. under normal pressure for 1 hour, and azeotropically removing about 200 g of the mixture of water and butylamine twice. Repeated. Next, while maintaining the pressure at 60-80 ° C. while reducing the pressure to about 10 mmHg for 1.5 hours, the remaining water and butylamine are removed to produce a Michael addition reaction having one secondary amino group and a ketonic carbonyl group. Product 2 was obtained. The amine value of the obtained Michael addition reaction product 2 was 230 mgKOH / g.

(Production Example 3)
Production of Michael addition reaction product 3 Air in a 2 L flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet was replaced with nitrogen, and 507.7 g of diacetone acrylamide, 270. water. 3 g and 642.9 g of benzylamine were added and stirred, and the temperature was raised to 80 ° C. and maintained at 80 ° C. for 2 hours. Next, thin film distillation was performed on a wall surface at a reduced pressure of 5 mmHg and 100 ° C. using a thin film distillation apparatus to remove a mixture of water and unreacted benzylamine. Thereafter, air in a 2 L flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet was replaced with nitrogen, and about 900 g of reaction product from which unreacted benzylamine was removed by thin film distillation was added to 500 g of water. Was added, and the temperature was raised to 105 ° C., and kept at 103 to 105 ° C. for 1 hour under normal pressure to hydrolyze ketimine. Furthermore, thin film distillation is performed on a wall at 100 ° C. under reduced pressure of 5 mmHg to remove a mixture of benzylamine formed by hydrolysis of water and ketimine, thereby having one secondary amino group in one molecule, and a ketone. A Michael addition reaction product 3 having a neutral carbonyl group was obtained. Since a peak of 6.19 to 6.23 ppm attributable to diacetone acrylamide was not observed in 1H-NMR measurement of the product using deuterated chloroform solvent, it was confirmed that no unreacted diacetone acrylamide remained. The amine value of the resulting Michael addition reaction product 3 was 211 mgKOH / g.

(Production Example 4)
Production of Michael addition reaction product 4 Air in a 1 L flask equipped with a stirrer, thermometer, condenser, nitrogen gas inlet was purged with nitrogen, 338.4 g of diacetone acrylamide, deionized water 180.2 g and ethylenediamine 240.4 g were added and stirred, and the temperature was raised to 80 ° C. and maintained at 80 ° C. for 3 hours. Next, the pressure was reduced to about 100 mmHg, and the mixture was kept at 60 to 80 ° C. for 2 hours to azeotropically remove the mixture of water and unreacted ethylenediamine. Thereafter, 200 g of water was added and held at 80 ° C. for 1 hour, then held at 60 to 80 ° C. for 1.5 hours while reducing the pressure to about 100 mmHg, and the operation of azeotropically removing about 200 g of the mixture of water and ethylenediamine was repeated twice. It was. Then, while reducing the pressure to about 10 mmHg, the mixture was held at 60 to 80 ° C. for 1.5 hours, and the remaining water and ethylenediamine were removed to obtain a Michael addition reaction product 4 having an amino group and a ketonic carbonyl group. Since a peak of 6.19 to 6.23 ppm attributable to diacetone acrylamide was not observed in 1H-NMR measurement of the product using deuterated chloroform solvent, it was confirmed that no unreacted diacetone acrylamide remained.

(Production Example 5)
Production of Michael addition reaction product 5 Air in a 1 L flask equipped with a stirrer, thermometer, condenser, nitrogen gas inlet was replaced with nitrogen, 338.4 g of diacetone acrylamide, deionized water 180.2 g and 150.2 g of N-methylethanolamine were added, stirred, heated to 100 ° C. and held at 100 ° C. for 14 hours to give a Michael addition reaction product 5 having one hydroxyl group and a ketonic carbonyl group Got. Since a peak of 6.19 to 6.23 ppm attributable to diacetone acrylamide was not observed in 1H-NMR measurement of the product using deuterated chloroform solvent, it was confirmed that no unreacted diacetone acrylamide remained.

Example 1
Production of modified polyolefin aqueous dispersion I-1 Air in a 1 L flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet was purged with nitrogen, and Supercron 851L (trade name, Japan) Paper Manufacturing Chemical Co., Ltd., pellets) (100.0 g) and tetrahydrofuran (hereinafter THF) (150.0 g) were added and heated to 60 ° C. and stirred until fully dissolved. After confirming dissolution, Michael addition reaction product 2 (6.0 g) was added dropwise over 30 minutes. After completion of dropping, the mixture was stirred for 30 minutes at the same temperature, and then measured for FT-IR (using a FT / IR-420 manufactured by JASCO Corporation, a sample was applied to a KBr plate and the spectrophotometer was measured with a transmission type), and it was 1638 cm. ^{In -1} , peak formation of an amide bond derived from the reaction of superclon 851L of maleic acid and the amine of Michael addition-reactive organism 2 was confirmed. Thereafter, n-butanol (20.0 g) was added and stirred for 30 minutes. After cooling to 40 ° C., dimethylethanolamine (4.96 g) was added and stirred for 15 minutes. After deionized water (300 g) was added dropwise over 30 minutes, the temperature was raised to 60 ° C., and the solvent was removed under reduced pressure to obtain an aqueous dispersion I-1 having a resin solid content of 25.0%.

(Example 2) to (Example 9)
Production of aqueous dispersions I-2 to I-9 Aqueous dispersions I-2 to I-9 were produced in the same manner as in Production Example 1 except that the components to be blended were as shown in Table 1 below.

（注１）スーパークロン８５１Ｌ：日本製紙株式会社製無水マレイン酸変性塩素化ポリオレフィン(塩素含有率１９％、軟化点：65〜75 ℃)
（注２）スーパークロン８０３ＭＷ：日本製紙株式会社製無水マレイン酸変性塩素化ポリオレフィン(塩素含有率２９.５％、軟化点：80〜90 ℃)
（注３）アウローレン２００：日本製紙株式会社製無水マレイン酸変性ポリオレフィン重量平均分子量：55000〜65000、軟化点：60〜70 ℃)
（注４）アウローレン１００：日本製紙株式会社製無水マレイン酸変性ポリオレフィン(重量平均分子量：45000〜55000、軟化点：75〜85 ℃)
（実施例１０）
変性ポリオレフィン水性分散体I−１０の製造
撹拌装置、温度計、冷却管、窒素ガス導入口を備えた１Ｌ容のフラスコ内の空気を窒素置換し、スーパークロン８５１Ｌ（１００.０ｇ）、ＴＨＦ（１５０.０ｇ）を加え、６０ ℃に加熱して、十分に溶解するまで、攪拌した。溶解を確認した後、マイケル付加反応生成物５（６.０ｇ）を３０分かけて滴下した。滴下終了後、トリエチルアミン（５．６３ｇ）を添加し同温度で１５分攪拌した。その後ｎ−ブタノール（２０.０ｇ）を添加し３０分攪拌した。４０ ℃まで冷却した後、脱イオン水（３００ｇ）を３０分かけて滴下したのちに６０ ℃まで昇温して、減圧脱溶剤を行い、樹脂固形分２５．０％の水性分散体Ｉ−１０を得た。

(Note 1) Supercron 851L: Nippon Paper Industries Co., Ltd. maleic anhydride modified chlorinated polyolefin (chlorine content 19%, softening point: 65-75 ° C.)
(Note 2) Super Clone 803 MW: Maleic anhydride-modified chlorinated polyolefin manufactured by Nippon Paper Industries Co., Ltd. (chlorine content 29.5%, softening point: 80-90 ° C.)
(Note 3) Aurorene 200: maleic anhydride modified polyolefin manufactured by Nippon Paper Industries Co., Ltd. Weight average molecular weight: 55000-65000, softening point: 60-70 ° C.)
(Note 4) Aurolen 100: maleic anhydride modified polyolefin manufactured by Nippon Paper Industries Co., Ltd. (weight average molecular weight: 45000-55000, softening point: 75-85 ° C.)
(Example 10)
Production of modified polyolefin aqueous dispersion I-10 The air in a 1 L flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet was purged with nitrogen, and superclon 851L (100.0 g) , THF (150.0 g) was added and heated to 60 ° C. and stirred until fully dissolved. After confirming dissolution, Michael addition reaction product 5 (6.0 g) was added dropwise over 30 minutes. After completion of dropping, triethylamine (5.63 g) was added and stirred at the same temperature for 15 minutes. Thereafter, n-butanol (20.0 g) was added and stirred for 30 minutes. After cooling to 40 ° C., deionized water (300 g) was added dropwise over 30 minutes, and then the temperature was raised to 60 ° C. to remove the solvent under reduced pressure to obtain an aqueous dispersion I-10 having a resin solid content of 25.0%. Got.

(Example 11)
Production of modified polyolefin aqueous dispersion I-11 Air in a 1 L flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet was purged with nitrogen, and Supercron 851 L (100.0 g) , THF (150.0 g) was added and heated to 60 ° C. and stirred until fully dissolved. After confirming dissolution, Michael addition reaction product 2 (6.0 g) was added dropwise over 30 minutes. After completion of dropping, the mixture was stirred at the same temperature for 30 minutes, and then heated to 80 ° C. while THF was distilled off under reduced pressure. While stirring, cyclohexane (100 g), Emanon 1112 (trade name, manufactured by Kao Chemical Co., Ltd., polyethylene oxide lauryl ester) (20 g), New Coal 240 (trade name, manufactured by Nippon Emulsifier Co., Ltd.) (6.6 g) were added. . Then, it cooled to 50 degreeC and deionized water (300g) was dripped over 2 hours. At the same temperature, cyclohexane was distilled off under reduced pressure to obtain an aqueous dispersion I-11 of a carbonyl-containing polyolefin resin.

(Comparative Example 1)
Air in a 1 L flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet was replaced with nitrogen, and superclone 851 L (100.0 g), THF (190.0 g), n-butanol (40. 0 g) was added and heated to 60 ° C. and stirred until fully dissolved. After confirming dissolution, dimethylethanolamine (3.0 g) was added and stirred for 15 minutes. The deionized water (300 g) was added dropwise over 2 hours, and then THF was distilled off under reduced pressure to obtain a chlorinated polyolefin resin aqueous dispersion I-12 having a solid content of 32%.

(Comparative Example 2)
Among the components to be blended, an aqueous dispersion I-13 was obtained in the same manner as in Comparative Example 1 except that Aurolen 200 was used instead of Supercron.

(Example 12)
Preparation of aqueous coating composition P-1 60 parts by weight of the above aqueous resin composition (I-1) and "Y Coat UX310" (manufactured by Sanyo Chemical Industries, Ltd., urethane dispersion) by solid weight. 20 parts by weight, 20 parts by weight of acrylic resin solution (W-1: Note 1), 50 parts “MICRO ACE K-1” (manufactured by Nippon Talc Co., Ltd., fine talc), “JR-806” (Taika Corporation) 50 parts by weight, manufactured by Titanium White Co., Ltd. and 2 parts of “MA100” (manufactured by Mitsubishi Chemical Corporation, carbon black) are added according to a conventional method, and then 10 parts of 10% adipic acid dihydrazide aqueous solution is added to obtain a solid content of 35%. Was diluted with deionized water to obtain an aqueous paint (P-1).

(Example 13) to (Example 26) and (Comparative Example 3) to (Comparative Example 7)
Preparation of water-based paint compositions (P-2) to (P-20) In Example 12, each water-based paint composition was carried out in the same manner as in Example 12 except that the blending composition was as shown in Table 2. Products (P-2) to (P-20) were obtained.

（注５）アクリル樹脂溶液（Ｗ−１）の製造
撹拌機、温度計、還流冷却管の備わった通常のアクリル樹脂反応槽に、エチレングリコールモノブチルエーテル３５部を仕込み、加熱撹拌して１１０℃に保持した。この中に、スチレン１０部、メチルメタクリレート４０部、ｎ−ブチルメタクリレート２５部、２−ヒドロキシエチルメタクリレート１０部、メタクリル酸３部、Ｎ，Ｎ−ジメチルアミノエチルメタクリレート５部（固形分量、脱イオン水１０部に溶解して配合）、「ＮＦバイソマーＰＥＭ６Ｅ」（第一工業製薬（株）製、商品名、ポリエチレングリコールモノメタクリレート、分子量約３５０）１０部、アゾビスイソブチロニトリル４部及びイソブチルアルコール２０部からなる混合物を３時間かけて滴下した。滴下終了後、１１０℃で３０分間熟成し、次にエチレングリコールモノブチルエーテル１５部及びアゾビスイソブチロニトリル０．５部からなる追加触媒混合液を１時間かけて滴下した。ついで１１０℃で１時間熟成したのち冷却し、固形分５５％のアクリル樹脂溶液Ｗ−１を得た。

(Note 5) Manufacture of acrylic resin solution (W-1)
A normal acrylic resin reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser was charged with 35 parts of ethylene glycol monobutyl ether and heated to 110 ° C. with stirring. In this, 10 parts of styrene, 40 parts of methyl methacrylate, 25 parts of n-butyl methacrylate, 10 parts of 2-hydroxyethyl methacrylate, 3 parts of methacrylic acid, 5 parts of N, N-dimethylaminoethyl methacrylate (solid content, deionized water) 10 parts dissolved in 10 parts), “NF biisomer PEM6E” (Daiichi Kogyo Seiyaku Co., Ltd., trade name, polyethylene glycol monomethacrylate, molecular weight about 350), 10 parts azobisisobutyronitrile and isobutyl alcohol A mixture of 20 parts was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was aged at 110 ° C. for 30 minutes, and then an additional catalyst mixture composed of 15 parts of ethylene glycol monobutyl ether and 0.5 part of azobisisobutyronitrile was added dropwise over 1 hour. Next, the mixture was aged at 110 ° C. for 1 hour and then cooled to obtain an acrylic resin solution W-1 having a solid content of 55%.

(Note 6) Production of aqueous acrylic resin dispersion (E-1)
Add 28.5 parts by weight of deionized water to a 2 liter four-necked flask and 0.1 part by weight of Newcol 707SF (manufactured by Nippon Emulsifier Co., Ltd., an anionic surfactant having a polyoxyethylene chain, nonvolatile content 30%), After nitrogen substitution, the temperature was kept at 85 ° C. In this, 36.8 parts by weight of deionized water, 15 parts by weight of styrene, 41.3 parts by weight of methyl methacrylate, 24 parts by weight of n-butyl acrylate, 15 parts by weight of 2-ethylhexyl acrylate, 2 parts by weight of diacetone acrylamide, 1, 6 parts of a pre-emulsion prepared by emulsifying 0.5 part by weight of 6-hexanediol diacrylate, 2 parts by weight of hydroxyethyl acrylate, 0.2 part by weight of acrylic acid, and 6.6 parts by weight of Newcol 707SF, and 0.5 part by weight 25% by weight of 10.5 parts by weight of a solution of ammonium persulfate dissolved in 10 parts by weight of deionized water was added, and the remaining pre-emulsion and the remaining ammonium persulfate aqueous solution were added dropwise over 4 hours 20 minutes after the addition. . After completion of the dropping, this was further maintained at 85 ° C. for 2 hours, and then cooled to 40-60 ° C. Next, the pH was adjusted to 8 to 9 with aqueous ammonia to obtain an acrylic resin aqueous dispersion E-1 having a solid content of 55% by weight. The pH of the emulsion was 8.3.
(Note 7) 10% adipic acid dihydrazide aqueous solution
Preparation of test coatings A polypropylene (degreased) plate was selected as shown in Table 3 for the water-based paint prepared as described above, and this was spray-coated to a dry film thickness of about 20 μm. Each test coating was prepared by heating and drying at 80 ° C. for 20 minutes.
Each test paint prepared as described above was subjected to the following performance test. The results are shown in Table 3.

性能試験方法
光沢：各試験塗装物の塗装面を目視で評価した。○はツヤがある状態、△はツヤが引けている状態、×はツヤがない状態を示す。
初期付着性：塗膜面に素地に達するようにカッターで切り込み線を入れ、大きさ２ｍｍ×２ｍｍのマス目を１００個作り、その表面に粘着セロハンテープを貼着し、２０℃においてそれを急激に剥離した後のマス目の残存塗膜数を調べた。
耐湿性：各試験塗装物を、５０ ℃で９８％ＲＨ下に１０日間静置してから、乾燥後の塗装面を目視で評価した。○はブリスター発生なし、△はツヤがひけているがブリスター発生のない状態、×はブリスター発生を示す。
耐溶剤性：各試験塗装物の塗膜面を、キシレンを湿らせたガーゼを１０枚重ねて、荷重約９．８Ｎを加えて１０往復ラビングした後、塗膜面を目視にて評価した。素地露出が認められない場合は○、塗膜が削れ素地が露出している場合は△、塗膜が溶けて素地が露出している場合は×で示す。

Performance test method Gloss: The painted surface of each test paint was visually evaluated. A circle indicates a glossy state, a triangle indicates a glossy state, and a cross indicates a glossless state.
Initial adhesion: Cut lines with a cutter to reach the substrate surface, make 100 squares with a size of 2mm x 2mm, stick adhesive cellophane tape on the surface, and rapidly apply it at 20 ° C The number of residual coatings in the squares after peeling was examined.
Moisture resistance: Each test coating was allowed to stand at 98 ° C. for 10 days at 50 ° C., and then the coated surface after drying was visually evaluated. ○ indicates no occurrence of blister, Δ indicates a state where gloss is lost but no blister is generated, and × indicates occurrence of blister.
Solvent resistance: Ten gauze moistened with xylene were stacked on the coating surface of each test coating, and the coating surface was evaluated by visual observation after 10 reciprocating rubs were applied with a load of about 9.8 N. When the substrate exposure is not recognized, it is indicated by ◯, when the coating is shaved and the substrate is exposed, Δ is indicated, and when the coating is melted and the substrate is exposed, × is indicated.

  The aqueous coating composition of the present invention can be applied to plastic resin molded products such as polyolefin.

Claims (5)

A modified polyolefin resin containing a carboxyl group and a ketonic carbonyl group in the side chain, wherein the modified polyolefin resin has at least one active hydrogen bonded to nitrogen and an amine compound (A1) and diacetone Modified polyolefin which is obtained by ring-opening addition reaction between compound (A) which is obtained by Michael addition reaction with acrylamide or vinyl ketones (A2) and acid anhydride group-containing polyolefin resin (B) Resin . A modified polyolefin resin aqueous dispersion obtained by dispersing the modified polyolefin resin according to claim 1 in a medium containing water. An aqueous coating composition comprising the modified polyolefin resin aqueous dispersion according to claim 2 and a hydrazine derivative. A method for coating a plastic molded product, comprising applying the aqueous coating composition according to claim 3 to a plastic molded product that may be surface-treated. A coated article obtained by the coating method according to claim 4 .