JP2013249426A - Coating composition and coated article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition capable of forming a coating film excellent in adhesion to plastic substrates such as a polyolefin and in water resistance even if under a low temperature backing condition, and to provide coated articles.SOLUTION: A coating composition includes: a block copolymer (I) of a weight average molecular weight of 2,000-500,000 which includes a polymer block (A) containing an epoxy group-having polymerizable unsaturated monomer (a1) unit and another polymerizable unsaturated monomer (a2) unit at a mass ratio of 5/95 to 100/0, and a polymer block (B) containing a polymerizable unsaturated monomer (a3) unit having at least one functional group selected from among a hydroxyl group, carboxyl group and amino group and another polymerizable unsaturated monomer (a4) unit at a mass ratio of 3/97 to 50/50; a polyolefin resin (II) which may be chlorinated; and a curing agent (III).

Description

  The present invention relates to a coating composition and a coated article capable of forming a coating film excellent in adhesion and water resistance to a plastic substrate such as polyolefin even under low-temperature baking conditions.

  A plastic molded product such as polyolefin is often used as a member of an automobile outer plate part, home appliance, or the like. These molded products are often pre-coated with a primer containing chlorinated polyolefin or the like in order to improve the adhesion between the top coat film and the molded product. However, in such primers, chlorinated polyolefins have low polarity, and other compounding components such as curing agents have high polarity, so the compatibility is insufficient due to the difference in polarity and adhesion of the formed coating film. There is a problem that the water resistance and water resistance are lowered.

  In order to improve the above problems, acrylic resins and polyester resins produced by random copolymerization as compatible resins with chlorinated polyolefins may be blended into the coating composition, but this eliminates the problems. Was insufficient. For example, in Patent Document 1, a macromonomer is produced by copolymerizing a copolymerizable unsaturated monomer (a) selected from methacrylic acid and a methacrylic acid ester, and a copolymerizable unsaturated monomer (b). A coating composition comprising an acrylic resin obtained by copolymerizing the macromonomer and a copolymerizable unsaturated monomer (c), and a mixture of chlorinated polyolefin resin and / or a reaction product. Is disclosed. However, in the coating composition disclosed in Patent Document 1, the stability of the coating is improved, but the low-temperature curability and adhesion of the formed coating film are insufficient.

  In order to improve adhesion to a plastic substrate without using chlorinated polyolefin, Patent Document 2 discloses a radically polymerizable monomer (A) as a macromonomer (B) having a polymerizable unsaturated group. The primer composition for coatings containing the polymer composition (C) obtained by polymerizing in the presence of water is disclosed, and Patent Document 3 discloses 4-tert-butylcyclohexyl (meth) acrylate obtained by controlled radical polymerization. A block copolymer having a polymer block and a coating composition containing the block copolymer are disclosed. However, the coating compositions disclosed in Patent Document 2 and Patent Document 3 are particularly insufficient in adhesion and water resistance to polyolefin substrates.

JP 2002-348526 A JP-A-2005-97435 JP 2009-256457 A

  An object of the present invention is to provide a coating composition and a coated article capable of forming a coating film excellent in adhesion to a plastic substrate such as polyolefin and water resistance even under low-temperature baking conditions.

As a result of intensive studies in order to solve the above-mentioned problems, the present inventors have used a specific block copolymer (I) as a compatibilizing agent, a polyolefin resin (II) which may be chlorinated, and By using the coating composition contained together with the curing agent (III), it has been found that the above problems can be solved, and the present invention has been completed.

  That is, the present invention comprises a polymerizable unsaturated monomer (a1) unit containing an epoxy group and another polymerizable unsaturated monomer (a2) unit in a mass ratio of 5/95 to 100/0. A polymer block (A), a polymerizable unsaturated monomer (a3) unit containing at least one functional group selected from a hydroxyl group, a carboxyl group and an amino group, and another polymerizable unsaturated monomer (a4) unit; A block copolymer (I) having a weight average molecular weight of 2,000 to 500,000, and a chlorinated polymer block (B) containing 3/97 to 50/50 in mass ratio A coating composition comprising a polyolefin-based resin (II) and a curing agent (III) which may be prepared, and a coated article obtained by coating the coating composition on the surface of a plastic substrate. To.

  According to the coating composition of the present invention, by containing the specific block copolymer (I) as a compatibilizing agent, a phase between a low polarity chlorinated polyolefin and another compounding component such as a high polarity curing agent is obtained. Capacitance is remarkably improved, and in addition, it is possible to form a coating film excellent in adhesion and water resistance to a plastic substrate such as polyolefin even under low temperature baking conditions.

  The coating composition of the present invention contains a block copolymer (I), an optionally chlorinated polyolefin resin (II), and a curing agent (III).

Block copolymer (I)
In the present invention, the block copolymer (I) is an epoxy group-containing polymerizable unsaturated monomer (a1) unit and other polymerizable unsaturated monomer (a2) unit in a mass ratio of 5/95 to 100/0. A polymer block (A) containing the polymerizable unsaturated monomer (a3) unit containing at least one functional group selected from a hydroxyl group, a carboxyl group and an amino group, and other polymerizable unsaturated groups. And a polymer block (B) containing the monomer (a4) unit in a mass ratio of 3/97 to 50/50.

  The polymer block (A) is composed of a polymerizable unsaturated monomer (a1) unit containing an epoxy group and other polymerizable unsaturated monomer (a2) units in a mass ratio of 5/95 to 100/0, preferably It contains so that it may become 8 / 92-80 / 20. If the polymerizable unsaturated monomer (a1) containing an epoxy group is less than this range, the resistance to hot water adhesion may be lowered.

  The polymerizable unsaturated monomer (a1) containing an epoxy group contains one or more epoxy groups selected from a glycidyl group, a 3,4-epoxycyclohexyl group, and a 2,3-epoxy-2-methylpropyl group. Examples include: glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate, allyl glycidyl ether, 2,3-epoxy-2-methylpropyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meta ) Acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate, and the like.

  The other polymerizable unsaturated monomer (a2) is a monomer that can be copolymerized with the monomer (a1) other than the polymerizable unsaturated monomer (a1) containing an epoxy group. For example, methyl (meth) acrylate, ethyl ( (Meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) Acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl acrylate (trade name, Osaka) Organic Chemistry), Cyclo Alkyl or cycloalkyl (meth) acrylates such as xyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, tricyclodecanyl (meth) acrylate; isobornyl ( Polymerizable unsaturated monomer having an isobornyl group such as meth) acrylate; polymerizable unsaturated monomer having an adamantyl group such as adamantyl (meth) acrylate; tricyclodecenyl group such as tricyclodecenyl (meth) acrylate Polymerizable unsaturated monomer having aromatic ring-containing polymerizable unsaturated monomer such as benzyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene; vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyl Triethoxysilane, vinylmethyldiethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltriisopropoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ -(Meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxypropylmethyldiethoxysilane, γ- (meth) acryloyloxypropyltri-n-propoxysilane, γ- (meth) acryloyloxypropyltriisopropoxy Polymerizable unsaturated monomers having hydrolyzable silyl groups such as silane, vinyltriacetoxysilane, β- (meth) acryloyloxyethyltrimethoxysilane; perfluorobutylethyl (meth) acrylate Perfluoroalkyl (meth) acrylates such as perfluorooctylethyl (meth) acrylate; polymerizable unsaturated monomers having fluorinated alkyl groups such as fluoroolefins; N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate , Vinyl compounds such as vinyl acetate; hydroxyl groups such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and allyl alcohol Polymerizable unsaturated monomer; 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl acid phosphate, 2-methacryloyl Phosphoric acid group-containing polymerizable unsaturated monomers such as ruoxypropyl acid phosphate; N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, (meth) acrylonitrile, (meth) acrylamide, Nitrogen-containing polymerizable unsaturated monomers such as methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, 2- (methacryloyloxy) ethyltrimethylammonium chloride, adducts of glycidyl (meth) acrylate and amines; 2-acrylamide- 2-methylpropanesulfonic acid, 2-sulfoethyl (meth) acrylate, allylsulfonic acid, 4-styrenesulfonic acid, etc .; polymerizable unsaturated mono-monomers having sulfonic acid groups such as sodium salts and ammonium salts of these sulfonic acids -; Carboxy group-containing polymerizable unsaturated monomers such as (meth) acrylic acid, maleic acid, crotonic acid, and β-carboxyethyl acrylate; polymerization having an acid anhydride group such as maleic anhydride, itaconic anhydride, citraconic anhydride, etc. Unsaturated unsaturated monomers and the like, and these can be used alone or in combination of two or more.

  Another polymerizable unsaturated monomer (a2) is a (meth) acrylic acid having a hydrocarbon group having 8 or more carbon atoms as a part of the component from the viewpoint of improving the compatibility of the paint blending component and the stability of the paint. It is desirable to include an ester. Examples of the (meth) acrylic acid ester having a hydrocarbon group having 8 or more carbon atoms include 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, stearyl (meth) acrylate, isostearyl acrylate ( Trade name, manufactured by Osaka Organic Chemical Co., Ltd.), lauryl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, tricyclodecanyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meta) ) Acrylate and the like. These can be used alone or in combination of two or more. Among these, (meth) acrylate having a hydrocarbon group having 10 or more carbon atoms is particularly preferable.

  In the present specification, “(meth) acrylate” means acrylate or methacrylate, and “(meth) acrylic acid” means acrylic acid or methacrylic acid. In addition, “(meth) acryloyl” means acryloyl or methacryloyl, and “(meth) acrylamide” means “acrylamide or methacrylamide”.

The polymer block (B) is different from the polymer block (A), and is a polymerizable unsaturated monomer (a3) unit containing at least one functional group selected from a hydroxyl group, a carboxyl group and an amino group. And other polymerizable unsaturated monomer (a4) units are contained in a mass ratio of 3/97 to 50/50, preferably 5/95 to 40/60. If the amount of the polymerizable unsaturated monomer (a3) containing at least one functional group selected from a hydroxyl group, a carboxyl group and an amino group is less than this range, the resistance to hot water adhesion of the resulting coating film may be decreased, and many In some cases, the compatibility of the paint blending components and the stability of the paint may be reduced.
Examples of the polymerizable unsaturated monomer (a3) containing at least one functional group selected from a hydroxyl group, a carboxyl group, and an amino group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3 -Monoesterified product of (meth) acrylic acid such as hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate and a dihydric alcohol having 2 to 8 carbon atoms, the (meth) acrylic acid and 2 to 2 carbon atoms Hydroxyl-containing polymerizable unsaturated monomers such as ε-caprolactone modified products of monoesterified products with dihydric alcohol of 8 and allyl alcohol; carboxyl groups such as (meth) acrylic acid, maleic acid, crotonic acid and β-carboxyethyl acrylate Containing polymerizable unsaturated monomer; N, N-dimethylaminoethyl ) Acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-di-t-butylaminoethyl (meth) acrylate, N, N-dimethylaminobutyl ( Examples thereof include tertiary amino group-containing polymerizable unsaturated monomers such as (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylamide, and these can be used alone or in combination of two or more.

  The other polymerizable unsaturated monomer (a4) is copolymerized with the monomer (a3) other than the polymerizable unsaturated monomer (a3) containing at least one functional group selected from a hydroxyl group, a carboxyl group and an amino group. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, Stearyl (meth) acrylate, iso Thearyl acrylate (trade name, manufactured by Osaka Organic Chemical Co., Ltd.), cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, tricyclodecanyl (meth) Alkyl or cycloalkyl (meth) acrylate such as acrylate; polymerizable unsaturated monomer having an isobornyl group such as isobornyl (meth) acrylate; polymerizable unsaturated monomer having an adamantyl group such as adamantyl (meth) acrylate; Polymerizable unsaturated monomers having a tricyclodecenyl group such as nyl (meth) acrylate; aromatic ring-containing polymerizable unsaturated monomers such as benzyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene; Rutrimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltriisopropoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- ( (Meth) acryloyloxypropylmethyldimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxypropylmethyldiethoxysilane, γ- (meth) acryloyloxypropyltri-n-propoxysilane, γ -Polymerization having hydrolyzable silyl groups such as (meth) acryloyloxypropyltriisopropoxysilane, vinyltriacetoxysilane, β- (meth) acryloyloxyethyltrimethoxysilane Unsaturated monomer; Perfluoroalkyl (meth) acrylate such as perfluorobutylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate; Polymerizable unsaturated monomer having a fluorinated alkyl group such as fluoroolefin; N-vinyl Vinyl compounds such as pyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate; 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl acid phosphate, 2-methacryloyloxypropyl acid phosphate Phosphoric acid group-containing polymerizable unsaturated monomers such as glycidyl (meth) acrylate, allyl glycidyl ether, 3,4-epoxycyclohexylethyl Polymerizable unsaturated monomers containing epoxy groups such as ru (meth) acrylate; (meth) acrylonitrile, (meth) acrylamide, methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, 2- (methacryloyloxy) ethyltrimethylammonium Nitrogen-containing polymerizable unsaturated monomers such as chlorides, adducts of glycidyl (meth) acrylate and amines; 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl (meth) acrylate, allylsulfonic acid, 4-styrene Polymerizable unsaturated monomers having sulfonic acid groups such as sodium salts and ammonium salts of these sulfonic acids; Polymerizable unsaturated monomers having acid anhydride groups such as maleic anhydride, itaconic anhydride and citraconic anhydride Etc. These may be used alone or in combination.

  Another polymerizable unsaturated monomer (a4) is a polymerizable unsaturated monomer having a ring structure as a part of the component or an acyclic group having 1 to 8 carbon atoms from the viewpoint of improving the warm water resistance of the resulting coating film. It is desirable to include a (meth) acrylic acid ester having a hydrocarbon group. Examples of the polymerizable unsaturated monomer having a ring structure and the (meth) acrylic acid ester having an acyclic hydrocarbon group having 1 to 8 carbon atoms include styrene, methyl (meth) acrylate, ethyl (meth) acrylate, n- Propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl ( Examples include meth) acrylate, cyclohexyl (meth) acrylate, 4-tert-butylcyclohexyl methacrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, and tricyclodecenyl (meth) acrylate. These can be used alone or in combination of two or more.

  The block copolymer (I) can be produced by a conventionally known method. Although the manufacturing method is not particularly limited, it is manufactured using, for example, an addition-cleavage type chain transfer agent which is 2,4-diphenyl-4-methyl-1-pentene from the viewpoint of coating film performance and economical efficiency of the manufacturing process. And a production method using a catalytic chain transfer agent that is a cobalt complex, and in particular, an addition cleavage type chain transfer agent that is 2,4-diphenyl-4-methyl-1-pentene. The method is preferred.

  Examples of the production method using an addition-cleavage chain transfer agent that is 2,4-diphenyl-4-methyl-1-pentene include the following (i) and (ii). In this method, from the viewpoint of suppressing a decrease in chain transferability of the polymerization at the time of production, 50 mol% or more of the polymerizable unsaturated monomer constituting the polymer block is a polymerizable unsaturated monomer having a methacryloyl group. Is appropriate.

  (I) In the presence of 2,4-diphenyl-4-methyl-1-pentene and a radical polymerization initiator, a polymerizable unsaturated monomer (a1) containing an epoxy group and other polymerizable unsaturated monomers (a2) The first monomer component containing is radical polymerized to produce a macromonomer having an ethylenically unsaturated group at the end corresponding to the polymer block (A), and then in the presence of the macromonomer, a hydroxyl group, carboxyl A radical addition-cleavage-type chain of a second monomer component containing a polymerizable unsaturated monomer (a3) containing at least one functional group selected from a group and an amino group and another polymerizable unsaturated monomer (a4) An AB block copolymer containing the polymer block (B) is produced by transfer polymerization.

  (Ii) A polymerizable unsaturated monomer containing at least one functional group selected from a hydroxyl group, a carboxyl group and an amino group in the presence of 2,4-diphenyl-4-methyl-1-pentene and a radical polymerization initiator A first monomer component containing (a3) and other polymerizable unsaturated monomer (a4) is radically polymerized to produce a macromonomer having an ethylenically unsaturated group at the end corresponding to the polymer block (B). Then, in the presence of the macromonomer, the second monomer component containing the polymerizable unsaturated monomer (a1) containing the epoxy group and the other polymerizable unsaturated monomer (a2) is radically added and cleaved. An AB block copolymer containing the polymer block (A) is produced by transfer polymerization.

  In the same manner, the block copolymer (I) is an ABA block polymer or BAB block polymer, and the monomers of the polymer blocks (A) and (B) such as the following (iii) and (iv) A monomer component having a composition different from that of the component may be subjected to radical addition-fragmentation chain transfer polymerization to form an ACB block copolymer, an ABC block copolymer, or the like.

  (Iii) In the presence of 2,4-diphenyl-4-methyl-1-pentene and a radical polymerization initiator, an epoxy group-containing polymerizable unsaturated monomer (a1) and other polymerizable unsaturated monomers (a2) To produce a macromonomer having an ethylenically unsaturated group at the end corresponding to the polymer block (A), and then in the presence of the macromonomer, the polymer block ( AC block comprising a polymer block (C) having an ethylenically unsaturated group at its terminal by radical addition-cleavage chain transfer polymerization of a second monomer component having a composition different from that of the monomer component of A) and (B) A polymerizable monomer having a macromonomer corresponding to a copolymer and further containing at least one functional group selected from a hydroxyl group, a carboxyl group and an amino group -ACB block copolymer containing polymer block (B) is prepared by radical addition-cleavage chain transfer polymerization of the third monomer component containing (a3) and other polymerizable unsaturated monomer (a4). .

  (Iv) A polymerizable unsaturated monomer containing at least one functional group selected from a hydroxyl group, a carboxyl group and an amino group in the presence of 2,4-diphenyl-4-methyl-1-pentene and a radical polymerization initiator A first monomer component containing (a3) and other polymerizable unsaturated monomer (a4) is radically polymerized to produce a macromonomer having an ethylenically unsaturated group at the end corresponding to the polymer block (B). Then, in the presence of the macromonomer, a second monomer component having a composition different from that of the polymer components of the polymer blocks (A) and (B) is subjected to radical addition-cleavage chain transfer polymerization to end the ethylenic group. A macromonomer corresponding to a BC block copolymer containing a polymer block (C) having a saturated group is produced, and an epoxy is further added in the presence of the macromonomer. ACB containing a polymer block (A) by radical addition-cleavage chain transfer polymerization of a third monomer component containing a polymerizable unsaturated monomer (a1) containing other polymerizable unsaturated monomer (a2) A block copolymer is produced.

  Further, ABAC, BABC, ABCA, BACB and the like may be obtained by multistage polymerization. In these cases, it is sufficient that at least one or more blocks of A and B are included, but if the number of stages is too large, the productivity decreases, so the number of stages is preferably 10 or less, preferably 4 or less. . In the multi-stage polymerization as described above, the unreacted residual monomer component at the previous polymerization may be brought in at the next polymerization.

  The amount of 2,4-diphenyl-4-methyl-1-pentene used is not particularly limited, but is usually 1 to 50 parts by mass, preferably 2 to 100 parts by mass of the first monomer component. It is suitable from the viewpoint of the molecular weight of the resin and the polymerization rate to be in the range of ˜30 parts by mass.

  The radical polymerization can be performed by a method such as solution polymerization in an organic solvent using 2,4-diphenyl-4-methyl-1-pentene which is an addition-cleavage type chain transfer agent.

  Examples of the radical polymerization initiator used for polymerization include cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5. -Trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, cumene hydroperoxide, 2,5-dimethylhexane-2, 5-dihydroperoxide, 1,3-bis (tert-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, diisopropylbenzene peroxide, tert-Butyl cumyl peroxide, decanoyl par Oxide, lauroyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, di-tert-amyl peroxide, bis (tert-butylcyclohexyl) peroxydicarbonate, tert-butylperoxybenzoate, 2,5- Peroxide polymerization initiators such as dimethyl-2,5-di (benzoylperoxy) hexane, tert-butylperoxy-2-ethylhexanoate; 2,2′-azobis (isobutyronitrile), 1 , 1-azobis (cyclohexane-1-carbonitrile), azocumene, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 4,4 ' -Azobis (4-cyanovaleric acid), 2- (t-butylazo) -2-cyanopropane, 2,2'-azobis Examples include azo polymerization initiators such as (2,4,4-trimethylpentane), 2,2'-azobis (2-methylpropane), dimethyl 2,2'-azobis (2-methylpropionate). it can.

  The organic solvent is not particularly limited and conventionally known solvents can be used, for example, hydrocarbon solvents such as n-butane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane, cyclobutane; toluene, xylene Aromatic solvents such as n-butyl ether, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol dimethyl ether; ethyl acetate, Ester solvents such as n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate; methyl ethyl ketone, methyl isobutyl Tons, ketone solvents such as diisobutyl ketone; may be mentioned amide solvents such as such as N- methylpyrrolidone; ethanol, isopropanol, n- butanol, sec- butanol, alcohol solvents such as isobutanol.

  When performing the first polymerization in solution polymerization in an organic solvent, 2,4-diphenyl-4-methyl-1-pentene, polymerization initiator, polymerizable unsaturated monomer component used in the first stage polymerization , And a method in which the organic solvent is mixed and heated while stirring, 2,4-diphenyl-4-methyl-1-pentene and the organic solvent are charged into the reaction vessel in order to suppress the temperature rise of the system due to reaction heat, and 60 ° C. A method in which a polymerizable unsaturated monomer component and a polymerization initiator used in the first stage polymerization are mixed and dropped over a predetermined time while stirring at a temperature of ˜250 ° C., 2,4-diphenyl- A method in which a part or all of 4-methyl-1-pentene is added to the polymerizable unsaturated monomer component used in the first stage polymerization and a method of mixing or dropping dropwise the polymerization initiator are used.In either case, polymerization may be performed in the presence of an inert gas such as nitrogen or argon as necessary.

  The second and subsequent polymerizations are methods in which the polymerization unsaturated monomer components used in the second and subsequent polymerizations are sequentially polymerized in the same reaction tank after the completion of the first polymerization reaction, and the first polymerization reaction product is reacted. A method in which the tank is charged and the second and subsequent polymerizations are sequentially performed in the presence of the tank, and the first and second polymerization reactions are sequentially performed, and then the third and subsequent polymerizations are performed in the reaction tank in which the second polymerization reaction is performed. The method includes, for example, a method in which the first and second polymerization reactions are sequentially performed, the reaction product is charged into a reaction vessel, and the third and subsequent polymerizations are performed in the presence thereof. In any case, aging time may be taken as necessary, and 2,4-diphenyl-4-methyl-1-pentene, the radical polymerization initiator and the organic solvent described above are directly added to the reaction vessel, It may be added by mixing with a polymerizable unsaturated monomer component used for the second and subsequent polymerizations.

  The polymerization can be generally performed in about 1 to 10 hours per stage. You may provide the additional catalyst process which heats a reaction tank, dripping a polymerization initiator as needed after superposition | polymerization of each step.

  The compounding amount of the monomer component in each of the above steps is based on the total monomer amount constituting the block copolymer (I), and a polymerizable unsaturated monomer containing an epoxy group constituting the polymer block (A) ( Polymerization containing a total amount (M1) of a1) and other polymerizable unsaturated monomers (a2) and at least one functional group selected from a hydroxyl group, a carboxyl group and an amino group constituting the polymer block (B) The total amount (M2) of the polymerizable unsaturated monomer (a3) and the other polymerizable unsaturated monomer (a4) is (M1): 5 to 95% by mass, preferably 10 to 90% by mass, (M2): 5 It is desirable to set it to -95 mass%, Preferably it is 10-90 mass% from the point of coating-film compatibility or coating-material stability. It is desirable that (M1) / (M2) = 1/19 to 19/1, preferably 1/10 to 10/1.

  The block copolymer (I) obtained as described above has a weight average molecular weight of 2,000 to 500,000, preferably 3,000 to 100,000, from the viewpoint of improving the warm water resistance of the resulting coating film. .

  In this specification, the weight average molecular weight and the number average molecular weight are values calculated based on the molecular weight of standard polystyrene from a chromatogram measured by gel permeation chromatograph (GPC). As the gel permeation chromatograph, “HLC8120GPC” (manufactured by Tosoh Corporation) was used. As the columns, four columns of “TSKgel G-4000HXL”, “TSKgel G-3000HXL”, “TSKgel G-2500HXL”, “TSKgel G-2000HXL” (both manufactured by Tosoh Corporation, trade name) were used, Mobile phase: Tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 cc / min, detector: RI

  The block copolymer (I) obtained as described above comprises a solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the polymer block (B). The solubility parameter value (SPB) difference (SPB-SPA) derived from the monomer composition is 0.2 or more, preferably 0.3 to 1.8, so that the compatibility of the paint compounding components is improved. And desirable from the viewpoint of the stability of the paint.

  The solubility parameter value derived from the monomer composition constituting the polymer block in the present invention is a value calculated according to the following procedure.

  Here, the solubility parameter value is a measure of compatibility.In the present invention, a resin for measuring the solubility parameter value is synthesized by the following method, and measured by the cloud point titration method. It is a numerical value obtained by The synthesis of the resin for measuring the solubility parameter value is performed according to the following procedure. First, 70 g of dipropylene glycol dimethyl ether is charged into a flask and maintained at 90 ° C. with stirring in a nitrogen atmosphere. A mixture of 100 g of a monomer mixture having the same composition as that of the polymer block, 15 g of dipropylene glycol dimethyl ether and 2 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) was added to this over 3 hours. Add a mixture of 15 g of dipropylene glycol dimethyl ether and 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) and ripen at 90 ° C. for 1 hour to measure the solubility parameter value. A solution of the resin is obtained. At this time, in order to ensure the solubility of the resin, a part of dipropylene glycol dimethyl ether may be substituted with another solvent as necessary. Next, in the cloud point titration method, the resin is dissolved in a good solvent, the poor solvent is added dropwise thereto, and the amount of the poor solvent required to produce white turbidity is measured. This is performed separately for two types of poor solvents (such as n-hexane) having a small solubility parameter value and poor solvents (such as deionized water) having a large solubility parameter value. Specifically, first, 0.5 g (solid content) of the resin to be measured is weighed into a 100 ml beaker and dissolved in 10 ml of tetrahydrofuran as a good solvent. Prepare two of these. Next, while stirring one of them, n-hexane, which is a poor solvent, is dropped into this using a burette, and the amount of n-hexane required to become cloudy is measured (this is referred to as H (ml)). For the other, similarly, the same experiment is performed using deionized water, which is a poor solvent, and the amount of deionized water required to become cloudy is measured (this is defined as W (ml)). Titration is performed in a constant temperature room at 20 ° C. The solubility parameter value is obtained by substituting H and W into the following equation.

Solubility parameter value = ((9.52 × (1-α) + 7.24 × α) × (√α) + (9.52 × (1-β) + 23.43 × β) × (√β)) / ((√α) + (√β))
However, α = H / (H + 10) and β = W / (W + 10).

  In addition, 9.52 is derived from the solubility parameter value of tetrahydrofuran, 7.24 is derived from the solubility parameter value of n-hexane, and 23.43 is derived from the solubility parameter value of deionized water.

  The content of the block copolymer (I) in the coating composition of the present invention is such that the block copolymer (I), a polyolefin resin (II) which may be chlorinated as described later, and a curing agent (III). The total resin solid content is 2 to 65% by mass, preferably 5 to 50% by mass, from the viewpoint of improving the stability of the paint and the warm water resistance of the resulting coating film.

Polyolefin resin (II) which may be chlorinated
Examples of the polyolefin resin (II) that may be chlorinated in the present invention include polyolefin resin, chlorinated polyolefin resin, etc., and adhesion to polyolefin materials such as automobile outer plates and exterior parts such as automobile bumpers. Use for improvement. When using chlorinated polyolefin resin, the chlorination rate is 50 mass% or less, Preferably it is 10-45 mass%, More preferably, it is 15-30 mass%. A non-chlorinated polyolefin resin and a chlorinated polyolefin resin may be used in combination.

  As the polyolefin resin, for example, at least one olefin selected from olefins having 2 to 10 carbon atoms, particularly 2 to 4 carbon atoms such as ethylene, propylene, butylene, hexene, octene, and decene is (co) polymerized. Polyolefins obtained from the above, and unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, (meth) acrylic acid (preferably unsaturated mono- or di-carboxylic acids) or unsaturated carboxylic acids thereof. Those obtained by graft polymerization according to a method known per se can be used, and those modified with maleic anhydride are preferred. Further, the unsaturated carboxylic acid or anhydride-modified polyolefin may be acrylic-modified, amine-modified, or alcohol-modified. Examples of polymerizable unsaturated monomers that can be used for acrylic modification include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, and cyclohexyl (meth). Alkyl esters of (meth) acrylic acid such as acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate; (meth) acrylic acid, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) ) Acrylic monomers such as acrylate, (meth) acrylamide, (meth) acrylonitrile; and styrene, and the like. These may be used alone or in combination of two or more. As the amine and alcohol, known ones can be used alone or in combination of two or more.

  Examples of the chlorinated polyfin resin include a resin obtained by chlorinating the above-mentioned polyolefin, and a maleic anhydride-modified chlorinated polyolefin resin obtained by reacting maleic anhydride after producing a chlorinated polyolefin resin. These may be further acrylic-modified, amine-modified, or alcohol-modified. Acrylic modification, amine modification, and alcohol modification can be performed in the same manner as described above.

  By using a maleic anhydride-modified polyolefin resin and / or a chlorinated polyolefin resin, it is possible to improve adhesion to the polyolefin resin molded article and paint stability.

  The polyolefin resin and the chlorinated polyolefin resin may have a functional group such as a hydroxyl group or a carboxyl group in the molecule, and the weight average molecular weight is 3,000 to 300,000, particularly 5,000 to 150,000. The range of is suitable.

  The content of the polyolefin resin (II) which may be chlorinated in the coating composition of the present invention is the sum of the block copolymer (I), the polyolefin resin (II) and the curing agent (III). It is suitable from the point of hot-water-resistant adhesiveness of the coating film obtained that it is 10-90 mass% on the basis of resin solid content mass, Preferably it is 20-70 mass%.

Curing agent (III)
In the present invention, examples of the curing agent (III) include polyisocyanate compounds, blocked polyisocyanate compounds, melamine resins, epoxy resins, and polycarbodiimide compounds.

  Examples of the polyisocyanate compound include aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, and lysine diisocyanate; burette type adducts, isocyanurate ring adducts of these aliphatic polyisocyanates, Allophanate type adducts, uretdione type adducts; alicyclic diisocyanates such as isophorone diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4- or -2,6-diisocyanate; -Type diisocyanate burette-type adducts, isocyanurate cycloadducts; xylylene diisocyanate, tetramethylxylylene diisocyanate , Aromatic diisocyanate compounds such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate; burette type adducts of these aromatic diisocyanates, isocyan Nurate ring adducts; hydrogenated MDI and derivatives of hydrogenated MDI; isocyanates at the hydroxyl groups of polyols such as ethylene glycol, propylene glycol, 1,4-butylene glycol, dimethylolpropionic acid, polyalkylene glycol, trimethylolpropane, hexanetriol Urethane adducts obtained by reacting polyisocyanate compounds in an excess ratio of groups; Burette type adducts of these urethanized adducts, isocyanurate cycloadditions And the like can be given.

  The blocked polyisocyanate compound is obtained by adding a blocking agent to the isocyanate group of the polyisocyanate compound, and the blocked polyisocyanate compound produced by the addition is stable at room temperature, but the baking temperature of the coating film ( When heated to about 80 to about 200 ° C.), it is desirable that the blocking agent can be dissociated to regenerate free isocyanate groups. Examples of the blocking agent that satisfies such requirements include, for example, phenol, lactam, alcohol, ether, oxime, active methylene, mercaptan, acid amide, imide, amine, imidazole, and pyrazole. And the like blocking agents. Of these, a blocked polyisocyanate compound using an active methylene-based or pyrazole-based blocking agent is particularly preferable.

  As the melamine resin, an alkyl etherified melamine resin etherified with an alkyl group such as methyl, ethyl, n-butyl, isobutyl, hexyl, 2-ethylhexyl is particularly preferable. These melamine resins may further have a methylol group, an imino group or the like. The melamine resin usually has a number average molecular weight in the range of 500 to 5,000, particularly 800 to 3,000.

  In the coating composition of the present invention, the content of the curing agent (III) is 5 based on the total resin solid mass of the block copolymer (I), the polyolefin resin (II) and the curing agent (III). It is suitable from the point of hot-water-adhesion property of the coating film obtained, and coating-material stability that it is -50 mass%, Preferably it is 10-40 mass%.

  The coating composition of the present invention essentially comprises the block copolymer (I), the polyolefin resin (II) which may be chlorinated, and the curing agent (III). Resins, urethane resins, acrylic resins other than (I), phenolic resins, polycarbonate resins, and other resin components can be contained, especially hydroxyl groups other than hydroxyl group-containing polyester resins (IV) and / or block copolymers (I) It is preferable to contain the containing acrylic resin (V).

  The hydroxyl group-containing polyester resin (IV) can be obtained, for example, by esterifying a polybasic acid and a polyhydric alcohol with an excess of hydroxyl groups by a method known per se. A polybasic acid is a compound having two or more carboxyl groups in one molecule. For example, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, 1,4-cyclohexanedicarboxylic acid, Examples include merit acid, itaconic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, dimer acid, hymic acid, succinic acid, het acid, and anhydrides thereof. The polyhydric alcohol is a compound having two or more hydroxyl groups in one molecule, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, butylene glycol, hexanediol, 2-ethyl-2- Examples include butyl-1,3-propanediol, cyclohexanedimethanol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol and the like. Introduction of a hydroxyl group can be performed, for example, by using a polyhydric alcohol having 3 or more hydroxyl groups in one molecule. Further, as the polyester resin, a fatty acid-modified polyester resin modified with a fatty acid such as soybean oil fatty acid, castor oil fatty acid, dehydrated castor oil fatty acid or the like can also be used. Moreover, the polyester resin may be modified with an epoxy compound such as butyl glycidyl ether, alkylphenyl glycidyl ether, or neodecanoic acid glycidyl ester, if necessary.

  The hydroxyl group-containing polyether resin (IV) usually has a hydroxyl value of 10 to 100 mgKOH / g, particularly 50 to 85 mgKOH / g, an acid value of 50 mgKOH / g or less, particularly 1 to 30 mgKOH / g, and a number average. A molecular weight in the range of 1,500 to 100,000, particularly 2,000 to 30,000 is suitable.

  The hydroxyl group-containing acrylic resin (V) is a hydroxyl group-containing acrylic resin other than the block copolymer (I) and is usually a hydroxyl group-containing polymerizable unsaturated monomer, a (meth) acrylic acid alkyl ester monomer, and other if necessary. The polymerizable unsaturated monomer can be obtained by polymerizing by a known polymerization method such as a solution polymerization method.

  The hydroxyl group-containing polymerizable unsaturated monomer is a compound having a hydroxyl group and a polymerizable unsaturated group, and examples thereof include (meth) acrylic compounds such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate. Examples include monoesterified products of acids and diols having 2 to 10 carbon atoms, and ε-caprolactone modified products of these compounds having a hydroxyl group and a (meth) acryloyl group. Examples of (meth) acrylic acid alkyl ester monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, ( Examples thereof include monoesterified products of (meth) acrylic acid and monoalcohol having 1 to 20 carbon atoms such as (meth) acrylic acid-2-ethylhexyl, (meth) lauryl acrylate, and stearyl (meth) acrylate. The other polymerizable unsaturated monomer is a compound having a polymerizable unsaturated group other than the hydroxyl group-containing polymerizable unsaturated monomer and the (meth) acrylic acid alkyl ester monomer, and examples thereof include (meth) acrylic acid and maleic acid. Examples thereof include carboxyl group-containing polymerizable unsaturated monomers such as: epoxy group-containing polymerizable unsaturated monomers such as glycidyl (meth) acrylate; (meth) acrylamide, acrylonitrile, styrene, vinyl acetate, vinyl chloride and the like.

  The hydroxyl group-containing acrylic resin (V) usually has a hydroxyl value of 10 to 100 mgKOH / g, particularly 50 to 90 mgKOH / g, an acid value of 10 to 100 mgKOH / g, particularly 30 to 60 mgKOH / g, and weight. The average molecular weight is suitably in the range from 2,000 to 100,000, in particular from 3,000 to 50,000.

  When the hydroxyl group-containing acrylic resin (V) other than the hydroxyl group-containing polyester resin (IV) and / or the block copolymer (I) is used in the coating composition of the present invention, the amount used thereof is the block copolymer ( I), with respect to 100 parts by mass of the total resin solid content of the polyolefin resin (II) and the curing agent (III), it is 5 to 90 parts by mass, preferably 10 to 60 parts by mass. It is suitable from the point of hot water adhesion.

  The coating composition of the present invention further comprises a color pigment, an extender pigment, a conductive pigment, an organic solvent, a silane coupling agent, a curing catalyst, a thickener, an antifoaming agent, a surface conditioning agent, and a film-forming aid, as necessary. An additive for paint such as an agent can be contained.

  Examples of color pigments include titanium oxide, carbon black, chrome lead, ocher, yellow iron oxide, Hansa Yellow, pigment yellow, chrome orange, chrome vermillion, permanent orange, amber, permanent red, brilliant carmine, fast violet, and methyl violet. Examples include rake, ultramarine, bitumen, cobalt blue, phthalocyanine blue, pigment green, naphthol green, and aluminum paste. Examples of extender pigments include talc, silica, calcium carbonate, barium sulfate, and zinc white (zinc oxide). Can be mentioned. These can be used alone or in combination of two or more.

  The conductive pigment is not particularly limited as long as it can impart conductivity to the coating film to be formed, and any pigment, flake, or fiber (including whisker) shape can be used. be able to. Specific examples include conductive carbon such as conductive carbon black, carbon nanotube, carbon nanofiber, and carbon microcoil; metal powder such as silver, nickel, copper, graphite, and aluminum, and further doped with antimony. Tin oxide coated with phosphorus, tin oxide doped with phosphorus, acicular titanium oxide surface coated with tin oxide / antimony, antimony oxide, zinc antimonate, indium tin oxide, carbon and graphite whiskers coated with tin oxide, etc. Pigment having a flake-like mica surface coated with a conductive metal oxide such as tin oxide or antimony-doped tin oxide; a conductive pigment containing tin oxide and phosphorus on the titanium dioxide particle surface, etc. Can be used alone or in combination of two or more. . Of these, conductive carbon can be particularly preferably used.

  The organic solvent is not particularly limited as long as it can mix and dissolve or disperse the above-described resin components. For example, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, alcohol solvents, ester solvents And solvents such as ketone solvents.

  Examples of the silane coupling agent include 2- (3,4 epoxy cyclohexyl) ethyl trialkoxysilane, 3-glycidoxypropyltrialkoxysilane, 3-glycidoxypropylmethyl dialkoxysilane, N-2- (amino Ethyl) -3-aminopropylmethyl dialkoxysilane, N-2- (aminoethyl) -3-aminopropyltrialkoxysilane, 3-aminopropyltrialkoxysilane, 3-aminopropylmethyl dialkoxysilane, 3-mercaptopropyl Methyl dialkoxysilane, 3-mercaptopropyltrialkoxysilane, N-phenyl-3-aminopropyltrialkoxysilane, 3-ureidopropyltrialkoxysilane, 3-chloropropyltrialkoxysilane, bis (trialkoxy) Rirupuropiru) tetrasulfide, etc. may be mentioned 3-isocyanate propyl trialkoxysilane, they may be used either alone or in combination of two or more.

  As described above, the coating composition of the present invention can be applied to the surface of a plastic substrate. As the plastic substrate, for example, a polyolefin obtained by (co) polymerizing one or more of olefins having 2 to 10 carbon atoms such as ethylene, propylene, butylene, and hexene is particularly suitable. In addition, polycarbonate, ABS resin, urethane resin, polyamide and the like can also be mentioned. Examples of molded articles made of these plastic substrates include automobile outer plate parts such as bumpers, spoilers, grills, and fenders; and home appliance outer plate parts. Prior to the coating of the coating composition of the present invention, these plastic molded products can be appropriately subjected to degreasing treatment, washing treatment, etc. by a method known per se.

  The coating of the coating composition of the present invention is performed by applying air spray, airless spray, dip coating, brush, etc. on the plastic substrate surface so that the dry film thickness is usually within the range of 1 to 20 μm, preferably 2 to 10 μm. It is suitable to use. After coating of the composition, the obtained coating surface can be set at room temperature for about 30 seconds to 60 minutes, if necessary, or preheated at a temperature of about 40 to about 80 ° C. for about 1 to 60 minutes ( Can be preheated), or can be cured by heating at a temperature of about 60 to about 140 ° C., preferably about 70 to about 120 ° C. for about 20 to 40 minutes. It is possible to perform the top coating of the next step without preheating after coating the coating composition. After coating the coating composition of the present invention, the coating composition is set at room temperature (about 20 to about 35 ° C.) for about 30 seconds to 3 minutes. Is preferred.

  In the present invention, the top coating material can be applied to the coating surface of the coating composition of the present invention. As the top coating, a colored coating or a clear coating may be used alone, or the base coating and the clear coating may be sequentially applied using the colored coating as a base coating. In addition, as a colored base coating layer, for example, a white base coating and an interference pearl base coating may be sequentially applied on the coating by the coating composition of the present invention to form a multilayer film.

  As the colored paint, those known per se can be used. Usually, an organic solvent and / or water as a main solvent, a colored component such as a colored pigment, a bright pigment and a dye, a base resin, a crosslinking agent, etc. The thing containing the resin component of this can be used.

  Examples of the base resin used in the colored paint include resins such as acrylic resins, polyester resins, and alkyd resins having reactive functional groups such as hydroxyl groups, epoxy groups, carboxyl groups, and silanol groups. . Examples of the crosslinking agent include amino resins such as melamine resins and urea resins, (block) polyisocyanates, polyepoxides, polycarboxylic acids, and the like having a reactive functional group capable of reacting with the functional group.

  The colored paint contains paint additives such as extender pigments, curing catalysts, UV absorbers, coating surface conditioners, rheology control agents, antioxidants, antifoaming agents, waxes, and preservatives as necessary. be able to.

  The colored paint is a dry film thickness on the coating film of the present uncured or cured present paint composition, usually 5 to 50 μm, preferably 5 to 30 μm, more preferably 10 to 20 μm. The coating surface to be obtained can be set at room temperature for about 1 to 60 minutes, if necessary, or preheated at a temperature of about 40 to about 80 ° C. for about 1 to 60 minutes, Alternatively, it can be cured by heating at a temperature of about 60 to about 140 ° C., preferably about 80 to about 120 ° C. for about 20 to 40 minutes. In the present invention, it is particularly preferable to perform clear coating without curing the colored base paint after coating.

  Examples of the clear paint include a resin component such as a base resin and a crosslinking agent, an organic solvent, water, and the like. Further, if necessary, an ultraviolet absorber, a light stabilizer, a curing catalyst, a coating surface conditioner, An organic solvent-based or water-based thermosetting paint that contains paint additives such as rheology control agents, antioxidants, antifoaming agents, and waxes. It is possible to use one having transparency to the extent that it can be performed.

  Examples of the base resin include acrylic resin, polyester resin, alkyd resin, fluororesin, urethane resin, and silicon-containing resin containing at least one reactive functional group such as a hydroxyl group, a carboxyl group, a silanol group, and an epoxy group. In particular, a hydroxyl group-containing acrylic resin is suitable. As said crosslinking agent, it has a reactive functional group which can react with these functional groups, melamine resin, urea resin, (block) polyisocyanate compound, epoxy compound, carboxyl group-containing compound, acid anhydride, alkoxysilane group-containing Examples of the compound include polyisocyanate compounds.

  The clear coating is applied on an uncured or cured colored base coating so that the dry film thickness is usually within the range of 10 to 50 μm, preferably 20 to 40 μm. If necessary, the surface is set at room temperature for about 1 to 60 minutes, or preheated at a temperature of about 40 to about 80 ° C. for about 1 to 60 minutes, and then about 60 to about 140 ° C., preferably about 70 to It can be carried out by heating and curing at a temperature of about 120 ° C. for about 20 to 40 minutes.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited only to these Examples. Note that “part” and “%” indicate “part by mass” and “% by mass”, respectively, unless otherwise specified.

Production of block copolymer (I) Production Example 1
Charge 10 parts of “Swazol 1000” (manufactured by Maruzen Petrochemical Co., Ltd., hydrocarbon solvent) and 2 parts of 2,4-diphenyl-4-methyl-1-pentene to the flask and raise the temperature to 155 ° C. under a nitrogen stream. did. To this, 6 parts glycidyl methacrylate, 14 parts 2-ethylhexyl methacrylate, 5 parts lauryl methacrylate, 4 parts isobornyl methacrylate, 1 part 2-ethylhexyl acrylate, 1.5 parts di-t-amyl peroxide, and "Swazole 1000" 10 parts of the mixture was added dropwise to obtain a solution of the polymer block (A). The weight average molecular weight was about 3,000. Next, this solution is kept at 90 ° C., and 15 parts of 2-hydroxyethyl methacrylate, 5 parts of 2-hydroxyethyl acrylate, 45 parts of 2-ethylhexyl methacrylate, 2 parts of lauryl methacrylate, 2 parts of isobornyl methacrylate, 2-ethylhexyl A mixed solution of 1 part of acrylate, 1 part of 2,2′-azobis (2,4-dimethylvaleronitrile) and 20 parts of isobutyl acetate was added dropwise, and 2,2′-azobis (2,4-dimethylvaleronitrile) 0 was further added. .5 parts was added to produce a polymer block (B) to obtain a solution (P-1) containing an AB type block copolymer. The weight average molecular weight was about 10,000 and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 0.8.

Production Example 2
10 parts of “Swazole 1000” and 6.5 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask, and the temperature was raised to 140 ° C. under a nitrogen stream. To this, a mixture of 16.5 parts of glycidyl methacrylate, 3 parts of 2-ethylhexyl methacrylate, 30 parts of lauryl methacrylate, 3 parts of t-butyl-peroxy-2-ethylhexanoate and 10 parts of “Swazole 1000” was dropped. A solution of polymer block (A) was obtained. The weight average molecular weight was about 3,000. Next, this solution is kept at 90 ° C., 14 parts of 2-hydroxyethyl methacrylate, 31 parts of 2-ethylhexyl methacrylate, 5.5 parts of isobutyl methacrylate, 2,2′-azobis (2,4-dimethylvaleronitrile) 1 A mixture of 20 parts of isobutyl acetate and 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) is added to form a polymer block (B), which is AB type. A solution (P-2) containing a block copolymer was obtained. The weight average molecular weight was about 6,000, and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 0.7.

Production Example 3
10 parts of “Swazole 1000” and 2 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask and heated to 155 ° C. under a nitrogen stream. To this, a mixture of 20 parts of glycidyl methacrylate, 1 part of isobornyl methacrylate, 8 parts of stearyl methacrylate, 1 part of cyclohexyl methacrylate, 1.4 parts of di-t-amyl peroxide, and 10 parts of dipropylene glycol dimethyl ether was added dropwise. A solution of the combined block (A) was obtained. The weight average molecular weight was about 3,000. Next, this solution is kept at 90 ° C., and 20 parts of 2-hydroxyethyl methacrylate, 0.1 part of methacrylic acid, 39 parts of 2-ethylhexyl methacrylate, 9.9 parts of isobornyl methacrylate, 1 part of styrene, 2, 2 A mixed solution of 0.9 part of '-azobis (2,4-dimethylvaleronitrile) and 20 parts of isobutyl acetate was added dropwise, and 0.5 part of 2,2'-azobis (2,4-dimethylvaleronitrile) was further added. The polymer block (B) was generated to obtain a solution (P-3) containing an AB type block copolymer. The weight average molecular weight was about 10,000 and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 0.4.

Production Example 4
10 parts of “Swazole 1000” and 2.2 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask and heated to 155 ° C. under a nitrogen stream. To this, a mixture of 5 parts of glycidyl methacrylate, 25 parts of lauryl methacrylate, 19 parts of isobornyl methacrylate, 1 part of isobutyl methacrylate, 1.3 parts of di-t-amyl peroxide and 10 parts of “Swazole 1000” was added dropwise. A solution of the combined block (A) was obtained. The weight average molecular weight was about 4,000. Next, this solution is kept at 90 ° C., 14 parts of 2-hydroxyethyl methacrylate, 4 parts of 2-hydroxyethyl acrylate, 0.1 part of 2- (dimethylamino) ethyl methacrylate, 19 parts of 2-ethylhexyl methacrylate, lauryl methacrylate 2.9 parts, 10 parts of cyclohexyl methacrylate, 1 part of 2,2′-azobis (2,4-dimethylvaleronitrile) and 20 parts of isobutyl acetate were added dropwise, and 2,2′-azobis (2,4 -Dimethylvaleronitrile) 0.5 part was added, the polymer block (B) was produced | generated, and the solution (P-4) containing an AB type block copolymer was obtained. The weight average molecular weight was about 10,000 and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 1.3.

Production Example 5
10 parts of “Swazole 1000” and 2 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask and heated to 155 ° C. under a nitrogen stream. To this, 9 parts glycidyl methacrylate, 2 parts 3,4-epoxycyclohexylmethyl methacrylate, 1 part 2-ethylhexyl methacrylate, 17 parts lauryl methacrylate, 1 part isobornyl methacrylate, 1.5 parts di-t-amyl peroxide, and A mixture of 10 parts of dipropylene glycol dimethyl ether was added dropwise to obtain a polymer block (A) solution. The weight average molecular weight was about 3,000. Next, this solution is kept at 115 ° C., 1 part 2-hydroxyethyl methacrylate, 6 parts 2-hydroxyethyl acrylate, 25 parts 2-ethylhexyl methacrylate, 11 parts isobornyl methacrylate, 2 parts 2-ethylhexyl acrylate, isobutyl A mixed solution of 15 parts of methacrylate, 10 parts of cyclohexyl methacrylate, 1 part of t-butyl-peroxy-2-ethylhexanoate and 20 parts of isobutyl acetate is added dropwise, and 2,2′-azobis (2,4-dimethylvaleronitrile is further added. ) 0.5 part was added to produce a polymer block (B) to obtain a solution (P-5) containing an AB type block copolymer. The weight average molecular weight was about 10,000 and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 0.4.

Production Example 6
10 parts of ethylene glycol monobutyl ether and 2 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask and heated to 155 ° C. under a nitrogen stream. To this, glycidyl methacrylate 10 parts, 2,3-epoxy-2-methylpropyl methacrylate 2 parts, 2-ethylhexyl methacrylate 8 parts, lauryl methacrylate 10 parts, di-t-amyl peroxide 1.5 parts, and dipropylene glycol A mixture of 10 parts of dimethyl ether was added dropwise to obtain a polymer block (A) solution. The weight average molecular weight was about 3,000. Next, this solution was kept at 115 ° C., 14 parts 2-hydroxyethyl methacrylate, 30 parts 2-ethylhexyl methacrylate, 10 parts isobornyl methacrylate, 1 part styrene, 15 parts isobutyl methacrylate, t-butyl-peroxy-2 -A mixture of 1 part of ethylhexanoate and 20 parts of isobutyl acetate is added dropwise, and 0.5 part of 2,2'-azobis (2,4-dimethylvaleronitrile) is further added to form a polymer block (B). To obtain a solution (P-6) containing an AB type block copolymer. The weight average molecular weight was about 10,000 and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 0.4.

Reference Example 1 (for comparative example)
10 parts of “Swazole 1000” and 2 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask and heated to 155 ° C. under a nitrogen stream. To this 0.3 parts glycidyl methacrylate, 14 parts 2-ethylhexyl methacrylate, 10.7 parts lauryl methacrylate, 4 parts isobornyl methacrylate, 1 part 2-ethylhexyl acrylate, 1.5 parts di-t-amyl peroxide, and A mixture of 10 parts of dipropylene glycol dimethyl ether was dropped to obtain a solution of the polymer block (A). The weight average molecular weight was about 3,000. Next, this solution is kept at 90 ° C., and 15 parts of 2-hydroxyethyl methacrylate, 5 parts of 2-hydroxyethyl acrylate, 45 parts of 2-ethylhexyl methacrylate, 2 parts of lauryl methacrylate, 2 parts of isobornyl methacrylate, 2-ethylhexyl A mixed solution of 1 part of acrylate, 1 part of 2,2′-azobis (2,4-dimethylvaleronitrile) and 20 parts of isobutyl acetate was added dropwise, and 2,2′-azobis (2,4-dimethylvaleronitrile) 0 was further added. .5 parts was added to produce a polymer block (B) to obtain a solution (Q-1) containing an AB type block copolymer. The weight average molecular weight was about 10,000 and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 1.0.

Reference Example 2 (for comparative example)
10 parts of “Swazole 1000” and 6.5 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask, and the temperature was raised to 140 ° C. under a nitrogen stream. A mixture of 3 parts of 2-ethylhexyl methacrylate, 46.5 parts of lauryl methacrylate, 3 parts of t-butyl-peroxy-2-ethylhexanoate, and 10 parts of ethylene glycol monobutyl ether was added dropwise to the polymer block ( A solution of A) was obtained. The weight average molecular weight was about 3,000. Next, this solution is kept at 90 ° C., and 35 parts of 2-hydroxyethyl methacrylate, 10 parts of 2-ethylhexyl methacrylate, 5.5 parts of isobutyl methacrylate, 2,2′-azobis (2,4-dimethylvaleronitrile) 1 A mixture of 20 parts of ethylene glycol monobutyl ether is added dropwise, and 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) is further added to form a polymer block (B). A solution (Q-2) containing a B-type block copolymer was obtained. The weight average molecular weight was about 6000, and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 2.4.

Reference Example 3 (for comparative example)
10 parts of “Swazole 1000” and 2 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask and heated to 155 ° C. under a nitrogen stream. To this, a mixture of 5 parts of glycidyl methacrylate, 11 parts of 2-ethylhexyl methacrylate, 14 parts of lauryl methacrylate, 1.5 parts of di-t-amyl peroxide, and 10 parts of dipropylene glycol dimethyl ether was dropped to form a polymer block (A ) Was obtained. The weight average molecular weight was about 3000. Next, this solution was kept at 90 ° C., and 1 part of 2-hydroxyethyl methacrylate, 50 parts of 2-ethylhexyl methacrylate, 19 parts of isobutyl methacrylate, 1 part of 2,2′-azobis (2,4-dimethylvaleronitrile), A mixed solution of 20 parts of isobutyl acetate was added dropwise, and 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) was further added to form a polymer block (B). A solution (Q-3) containing a polymer was obtained. The weight average molecular weight was about 10,000 and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 0.1.

Production Example 7
10 parts of dipropylene glycol dimethyl ether and 2.5 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask and heated to 155 ° C. under a nitrogen stream. To this, 18 parts of 2-hydroxyethyl methacrylate, 2 parts of 2-hydroxyethyl acrylate, 37 parts of 2-ethylhexyl methacrylate, 3 parts of isobutyl methacrylate, 10 parts of cyclohexyl methacrylate, 2 parts of di-t-amyl peroxide, "Swazole 1000" 5 And a mixture of 5 parts of ethylene glycol monobutyl ether were added dropwise to obtain a solution of the polymer block (B). The weight average molecular weight was about 6,000. Next, this solution was kept at 90 ° C., and 10 parts of glycidyl methacrylate, 10 parts of 2-ethylhexyl methacrylate, 8 parts of lauryl methacrylate, 2 parts of isobornyl methacrylate, 2,2′-azobis (2,4-dimethylvaleronitrile) ) 1 part and a mixed solution of 20 parts of isobutyl acetate are added dropwise, and 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) is further added to form a polymer block (A). A solution (P-7) containing a B-type block copolymer was obtained. The weight average molecular weight was about 10,000 and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 0.8.

Production Example 8
10 parts of dipropylene glycol dimethyl ether and 6 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask and heated to 140 ° C. under a nitrogen stream. To this, 15 parts of 2-hydroxyethyl methacrylate, 0.1 part of methacrylic acid, 20 parts of 2-ethylhexyl methacrylate, 1.9 parts of lauryl methacrylate, 10 parts of isobornyl methacrylate, 3 parts of 2-ethylhexyl acrylate, t-butyl- A mixture of 3 parts of peroxy-2-ethylhexanoate, 5 parts of “Swazole 1000” and 5 parts of ethylene glycol monobutyl ether was added dropwise to obtain a polymer block (B) solution. The weight average molecular weight was about 6,000. Next, this solution is kept at 90 ° C., and 18 parts of glycidyl methacrylate, 5 parts of 2-ethylhexyl methacrylate, 26 parts of lauryl methacrylate, 1 part of styrene, 1 part of 2,2′-azobis (2,4-dimethylvaleronitrile) Then, a mixed solution of 20 parts of isobutyl acetate is dropped, and 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) is further added to form a polymer block (A), and an AB type block A solution (P-8) containing a copolymer was obtained. The weight average molecular weight was about 10,000 and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 0.6.

Reference Example 4 (for comparative example)
10 parts of dipropylene glycol dimethyl ether and 6 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask and heated to 140 ° C. under a nitrogen stream. To this, 15 parts of 2-hydroxyethyl methacrylate, 0.1 part of methacrylic acid, 20 parts of 2-ethylhexyl methacrylate, 1.9 parts of lauryl methacrylate, 10 parts of isobornyl methacrylate, 3 parts of 2-ethylhexyl acrylate, t-butyl- A mixture of 3 parts of peroxy-2-ethylhexanoate, 5 parts of “Swazole 1000” and 5 parts of ethylene glycol monobutyl ether was added dropwise to obtain a polymer block (B) solution. The weight average molecular weight was about 6000. Next, this solution is kept at 90 ° C., and a mixed solution of 5 parts of 2-ethylhexyl methacrylate, 45 parts of lauryl methacrylate, 1 part of 2,2′-azobis (2,4-dimethylvaleronitrile) and 20 parts of isobutyl acetate is added. Then, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) is further added to form a polymer block (A), and a solution containing a AB block copolymer (Q- 4) was obtained. The weight average molecular weight was about 10,000 and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA) was 1.2.

Production Example 9
10 parts of “Swasol 1000” and 6 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask, and the temperature was raised to 140 ° C. under a nitrogen stream. To this, 10 parts glycidyl methacrylate, 10 parts 2-ethylhexyl methacrylate, 8 parts lauryl methacrylate, 2 parts isobornyl methacrylate, 3 parts t-butyl-peroxy-2-ethylhexanoate, and 10 parts dipropylene glycol dimethyl ether The mixture was added dropwise to obtain a polymer block (A1) solution. The weight average molecular weight was about 3,000. Next, this solution is kept at 115 ° C., and 18 parts of 2-hydroxyethyl methacrylate, 2 parts of 2-hydroxyethyl acrylate, 40 parts of 2-ethylhexyl methacrylate, 7 parts of isobutyl methacrylate, 3 parts of cyclohexyl methacrylate, t-butyl-peroxy A mixture of 1 part of 2-ethylhexanoate and 20 parts of isobutyl acetate was added dropwise, and 0.3 part of 2,2′-azobis (2,4-dimethylvaleronitrile) was further added to form a polymer block (B). To obtain a solution containing an AB type block copolymer. The weight average molecular weight was about 10,000. To this, 18 parts of glycidyl methacrylate, 4 parts of 2-ethylhexyl methacrylate, 7 parts of isobornyl methacrylate, 1 part of cyclohexyl methacrylate, 0.5 part of t-butyl-peroxy-2-ethylhexanoate and 13 parts of "Swazole 1000" Then, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) is added to form a polymer block (A2), and an ABA type block copolymer is obtained. A solution (P-9) containing was obtained. The weight average molecular weight was about 130,000 and the solid content was about 70%. The solubility parameter value (SPA1) derived from the monomer composition constituting the polymer block (A1) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA1) is 0.7, which constitutes the polymer block (B) with the solubility parameter value (SPA2) derived from the monomer composition constituting the polymer block (A2). The difference (SPB-SPA2) in solubility parameter values (SPB) derived from the monomer composition was 0.4.

Reference Example 5 (for comparative example)
10 parts of “Swasol 1000” and 6 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask, and the temperature was raised to 140 ° C. under a nitrogen stream. To this was added dropwise a mixture of 10 parts 2-ethylhexyl methacrylate, 18 parts lauryl methacrylate, 2 parts isobornyl methacrylate, 3 parts t-butyl-peroxy-2-ethylhexanoate, and 10 parts dipropylene glycol dimethyl ether. A solution of the polymer block (A1) was obtained. The weight average molecular weight was about 3,000. Next, this solution is kept at 115 ° C., and 18 parts of 2-hydroxyethyl methacrylate, 2 parts of 2-hydroxyethyl acrylate, 40 parts of 2-ethylhexyl methacrylate, 7 parts of isobutyl methacrylate, 3 parts of cyclohexyl methacrylate, t-butyl-peroxy A mixture of 1 part of 2-ethylhexanoate and 20 parts of isobutyl acetate was added dropwise, and 0.3 part of 2,2′-azobis (2,4-dimethylvaleronitrile) was further added to form a polymer block (B). To obtain a solution containing an AB type block copolymer. The weight average molecular weight was about 10,000. To this, a mixture of 22 parts of 2-ethylhexyl methacrylate, 7 parts of isobornyl methacrylate, 1 part of cyclohexyl methacrylate, 0.5 part of t-butyl-peroxy-2-ethylhexanoate and 13 parts of “Swazole 1000” was added dropwise. Furthermore, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) is added to form a polymer block (A2), and a solution containing an ABA type block copolymer (Q- 5) was obtained. The weight average molecular weight was about 13,000 and the solid content was about 70%. The solubility parameter value (SPA1) derived from the monomer composition constituting the polymer block (A1) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The difference (SPB-SPA1) is 1.1, and constitutes the solubility parameter value (SPA2) derived from the monomer composition constituting the polymer block (A2) and the polymer block (B). The difference in the solubility parameter value (SPB) derived from the monomer composition (SPB-SPA2) was 1.0.

Production Example 10
10 parts of dipropylene glycol dimethyl ether and 4 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask and heated to 140 ° C. under a nitrogen stream. To this is a mixture of 9 parts 2-hydroxyethyl methacrylate, 20 parts 2-ethylhexyl methacrylate, 1 part cyclohexyl methacrylate, 1.8 parts t-butyl-peroxy-2-ethylhexanoate, and 10 parts "Swazole 1000". The solution was added dropwise to obtain a polymer block (B1) solution. The weight average molecular weight was about 4,000. Next, this solution was kept at 115 ° C., and mixed with 17 parts of glycidyl methacrylate, 3 parts of 2-ethylhexyl methacrylate, 30 parts of lauryl methacrylate, 1 part of t-butyl-peroxy-2-ethylhexanoate and 20 parts of isobutyl acetate. The solution was added dropwise, and further 0.3 part of 2,2′-azobis (2,4-dimethylvaleronitrile) was added to produce a polymer block (A) to obtain a solution containing a B-A type block copolymer. It was. The weight average molecular weight was about 8,000. To this, a mixture of 9 parts 2-hydroxyethyl methacrylate, 11 parts 2-ethylhexyl methacrylate, 10 parts isobutyl methacrylate, 0.5 parts t-butyl-peroxy-2-ethylhexanoate, and 13 parts "Swazole 1000" Then, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) is further added to form a polymer block (B2) and a solution containing a B-A-B type block copolymer ( P-10) was obtained. The weight average molecular weight was about 12,000, and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB1) derived from the monomer composition constituting the polymer block (B1) The difference (SPB1-SPA) is 0.8, and constitutes the solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the polymer block (B2). The difference (SPB2-SPA) in solubility parameter values (SPB2) derived from the monomer composition was 0.9.

Reference Example 6 (for comparative example)
10 parts of dipropylene glycol dimethyl ether and 4 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a flask and heated to 140 ° C. under a nitrogen stream. To this is a mixture of 21 parts 2-hydroxyethyl methacrylate, 8 parts 2-ethylhexyl methacrylate, 1 part cyclohexyl methacrylate, 1.8 parts t-butyl-peroxy-2-ethylhexanoate and 10 parts ethylene glycol monobutyl ether. Was dropped to obtain a polymer block (B1) solution. The weight average molecular weight was about 4,000. Next, this solution was kept at 115 ° C., and mixed with 17 parts of glycidyl methacrylate, 3 parts of 2-ethylhexyl methacrylate, 30 parts of lauryl methacrylate, 1 part of t-butyl-peroxy-2-ethylhexanoate and 20 parts of isobutyl acetate. The solution was added dropwise, and further 0.3 part of 2,2′-azobis (2,4-dimethylvaleronitrile) was added to produce a polymer block (A) to obtain a solution containing a B-A type block copolymer. It was. The weight average molecular weight was about 8,000. To this, a mixture of 16 parts 2-hydroxyethyl methacrylate, 11 parts 2-ethylhexyl methacrylate, 3 parts isobutyl methacrylate, 0.5 part t-butyl-peroxy-2-ethylhexanoate, and 13 parts ethylene glycol monobutyl ether. Then, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) is further added to form a polymer block (B2) and a solution containing a B-A-B type block copolymer ( Q-6) was obtained. The weight average molecular weight was about 12,000, and the solid content was about 70%. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB1) derived from the monomer composition constituting the polymer block (B1) The difference (SPB1-SPA) is 2.1, and constitutes a solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the polymer block (B2). The difference (SPB2-SPA) in solubility parameter values (SPB2) derived from the monomer composition was 1.5.

Production Example 11 of Curing Agent 11
In a flask, 142 parts of “Duranate TPA-100” (manufactured by Asahi Kasei Chemicals Co., Ltd., polyisocyanate, isocyanate content 23%) was charged, and while stirring, 76 parts of 3,5-dimethylpyrazole was added little by little. The reaction was performed at 110 ° C. Thereafter, 47 parts of 1-butanol and 50 parts of toluene were added, and it was confirmed that the reaction rate of the isocyanate group was 99% or more, and a solution of a blocked polyisocyanate curing agent (H-1) was obtained.

Production Example 12
In a flask, 142 parts of “Duranate TPA-100”, 60 parts of toluene and 140 parts of dibutyl malonate were added. While stirring, 1.3 parts of a 28% methanol solution of sodium methoxide was added and reacted at 70 ° C. for 10 hours. It was. Thereafter, 63 parts of 1-butanol was added and aged at 70 ° C. to obtain a solution of a blocked polyisocyanate curing agent (H-2).

Production and production example 13 of hydroxyl group-containing polyester resin
Into the flask, 218 parts of neopentyl glycol, 222 parts of 2-ethyl-2-butyl-1,3-propanediol, 158 parts of trimethylolpropane, 135 parts of adipic acid, 498 parts of hexahydrophthalic anhydride, 240 ° C. After dehydrating and condensing, 61 parts of trimellitic anhydride is added and reacted, and 120 parts of propylene glycol monopropyl ether and 300 parts of propylene glycol monomethyl ether are added to obtain a solution (J-1) containing a hydroxyl group-containing polyester resin. It was. The hydroxyl value of the hydroxyl group-containing polyester resin was about 80 mgKOH / g, the acid value was about 30 mgKOH / g, and the number average molecular weight was about 2,500.

Production and production example 14 of hydroxyl group-containing acrylic resin
To the flask, 500 parts of propylene glycol monopropyl ether and 400 parts of propylene glycol monomethyl ether were added, and the temperature was raised to 80 ° C. To this, 200 parts of 2-hydroxyethyl acrylate, 90 parts of 2-hydroxyethyl methacrylate, 44 parts of acrylic acid, 300 parts of isobutyl methacrylate, 400 parts of n-butyl acrylate, 1091 parts of 2-ethylhexyl methacrylate, 400 g part of propylene glycol monopropyl ether And 90 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) were added dropwise under a nitrogen stream, 450 parts of propylene glycol monomethyl ether was further added, and a solution containing a hydroxyl group-containing acrylic resin (J- 2) was obtained. The hydroxyl value of the hydroxyl group-containing acrylic resin was about 60 mgKOH / g, the acid value was about 15 mgKOH / g, and the number average molecular weight was about 10,000.

Preparation Example 1 of Coating Composition
"Supercron 892L" (Note 1) 50 parts (solid content), 30 parts (solid content) of block copolymer (P-1), 20 parts (solid content) curing agent (H-1), JR-806 ( Note 5) A mixture of 80 parts and 20 parts of Vulcan XC72 (Note 6) was mixed with a mixed solvent of xylene / toluene = 1/1 to obtain a coating composition (1 )

Examples 2 to 13 and Comparative Examples 1 to 7
The coating compositions (2) to (20) were obtained in the same manner as in Example 1 except that the composition was as shown in Table 1 in Example 1.

In addition, the mixing | blending of Table 1 is a solid content display, (Note 1)-(Note 6) in Table 1 are as follows.
(Note 1) Supercron 892L: trade name, manufactured by Nippon Paper Chemicals Co., Ltd., maleic anhydride modified chlorinated polypropylene, chlorination rate 22%, solid content 20%
(Note 2) Supercron 851L: trade name, manufactured by Nippon Paper Chemicals Co., Ltd., maleic anhydride modified chlorinated polypropylene, chlorination rate 19%, solid content 20%
(Note 3) Hardren DX-526P: trade name, manufactured by Toyobo Co., Ltd., chlorinated polypropylene, 26% chlorination rate (used as a toluene solution with a solid content of 20%)
(Note 4) Cymel 327: trade name, manufactured by Nippon Cytec Industries, Ltd., melamine resin, solid content 90%
(Note 5) JR-806: trade name, manufactured by Teika Co., Ltd., titanium oxide (Note 6) Vulcan XC72: trade name, manufactured by Cabot Specialty Chemicals Co., Ltd., conductive carbon black

  (* 1) Coating stability evaluation: After each coating composition (1) to (20) was stored at 40 ° C. for 10 days, the state in the container was visually observed and evaluated according to the following criteria.

○: Even if there is separation sedimentation or thickening, there is no problem of returning to the original state by hand stirring.

Preparation of test coating plate The above-prepared coating compositions (1) to (20) were spray-coated on a degreased polypropylene plate to a dry film thickness of 10 μm and set at room temperature for 10 seconds. Then, as a colored base paint, “SOFLEX 420” (trade name, colored base paint, manufactured by Kansai Paint Co., Ltd.) was electrostatically applied so as to have a dry film thickness of 15 μm. Next, “Soflex # 500 clear” (trade name, acrylic urethane organic solvent-type clear paint manufactured by Kansai Paint Co., Ltd.) is applied as a clear paint so as to have a dry film thickness of 30 μm. After leaving for a minute, it was heated at 95 ° C. for 30 minutes to obtain a test coating plate on which a multilayer coating film was formed. The multilayer coating film was tested for initial adhesion and resistance to hot water.

Performance test Each test coated plate produced as described above was subjected to the following performance test. The results are also shown in Table 1.

(* 2) Initial adhesion:
Cut with a cutter so that it reaches the base of the multi-layer coating film, make 100 grids with a width of 2 mm, adhere adhesive tape to the surface, and observe the remaining number of grid coating films after abrupt peeling at 20 ° C did.

○: remaining number / total number = 100/100 Δ: remaining number / total number = 90 to 99/100 ×: remaining number / total number = 89 or less / 100

(* 3) Warm water adhesion test After immersing the coated plate in warm water at 60 ° C for 24 hours, removing it, wiping off the water and cutting it with a cutter to reach the base of the multilayer coating film 100 square grids with a width of 2mm Then, the adhesive tape was adhered to the surface, and the remaining number of cross-cut coating film after the rapid peeling at 20 ° C. was observed.

○: remaining number / total number = 100/100 Δ: remaining number / total number = 90 to 99/100 ×: remaining number / total number = 89 or less / 100

Claims (10)

Polymer block comprising a polymerizable unsaturated monomer (a1) unit containing an epoxy group and another polymerizable unsaturated monomer (a2) unit in a mass ratio of 5/95 to 100/0 (A ) And a polymerizable unsaturated monomer (a3) unit containing at least one functional group selected from a hydroxyl group, a carboxyl group, and an amino group and other polymerizable unsaturated monomer (a4) unit in a mass ratio of 3 / A block copolymer (I) containing a polymer block (B) containing 97 to 50/50 and having a weight average molecular weight of 2,000 to 500,000, which may be chlorinated A coating composition comprising a polyolefin resin (II) and a curing agent (III). The coating composition according to claim 1, wherein the other polymerizable unsaturated monomer (a2) contains a (meth) acrylic acid ester having a hydrocarbon group having 8 or more carbon atoms as a part of the component. The solubility parameter value (SPA) derived from the monomer composition constituting the polymer block (A) and the solubility parameter value (SPB) derived from the monomer composition constituting the polymer block (B) The coating composition according to claim 1 or 2, wherein the difference (SPB-SPA) is 0.2 or more. The coating composition according to any one of claims 1 to 3, wherein the polyolefin resin (II) is a modified maleic anhydride. The content of the block copolymer (I) is 2 to 65% by mass based on the total resin solid mass of the components (I), (II) and (III). The coating composition according to Item. The coating composition according to any one of claims 1 to 5, further comprising a hydroxyl group-containing acrylic resin (V) other than the hydroxyl group-containing polyester resin (IV) and / or the block copolymer (I). A coated article obtained by applying the coating composition according to any one of claims 1 to 6 on a plastic substrate surface. A coating method comprising applying the coating composition according to any one of claims 1 to 6 on a plastic substrate surface, and then applying a clear coating to the coating surface. A coating method comprising applying the coating composition according to any one of claims 1 to 6 on a plastic substrate surface, and then sequentially applying a colored base coating and a clear coating onto the coating surface. A coated article obtained by the coating method according to claim 8 or 9.