JP2019099728A - Copolymer, leveling agent, coating composition and coating article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a smooth coating film and impart excellent scratch resistance to the obtained coating film, a copolymer, a leveling agent, a slipperiness improving agent, an abrasion resistance improving agent and the like. To provide a coating composition and a coating film using the above. A copolymer (C) containing a structural unit derived from a macromonomer (A) and a structural unit derived from a vinyl monomer (b), wherein the macromonomer (A) has 8 carbon atoms. It contains 20% by mass or more of a structural unit derived from a monomer (a1) having an alkyl group of ~ 24, has a number average molecular weight of 3,500 to 10,000, and has an SP value of 20 (J / cm3) 0.5. The SP value of the polymer (B) obtained by polymerizing the vinyl monomer (b) containing the vinyl monomer (b1) having a hydroxyl group is as follows. A copolymer having a value of 3.5 or more higher than the SP value of the macromonomer (A). [Selection diagram] None

Description

  The present invention is a copolymer, a leveling agent, a slipperiness imparting agent, an abrasion resistance improver, which can obtain a coating film excellent in finished appearance and excellent in scratch resistance by imparting smoothness to a coating film. The present invention relates to a paint composition (hereinafter, also simply referred to as "paint") and a coated article.

Paints to be coated on objects such as automobile bodies are required to be excellent in coating film performance such as scratch resistance and finished appearance.
Conventionally, as a paint for top coats for car bodies, thermosetting paint compositions using an acid-epoxy curing system excellent in acid resistance are known. The coating obtained from the acid / epoxy curing coating has a problem of durability, particularly the low appearance of the coating due to scratches. Scratches caused by car wash brushes, abrasives such as compounds and waxes, sand particles soaring while traveling, and contact with foreign matter are particularly noticeable, and in particular, the problem of scratches caused by car wash brushes of automatic car wash machines is strongly desired to be solved It is rare.

  Various coatings containing a polyisocyanate compound and a hydroxyl group-containing resin have been proposed as thermosetting coatings having excellent scratch resistance. For example, Patent Document 1 discloses a two-component curable paint containing a hydroxyl group-containing acrylic resin and a polyisocyanate compound.

JP, 2010-253384, A

  However, in the case of a coating obtained from a conventional paint, the surface hardness and the scratch resistance are in a trade-off relationship, and it was not easy to achieve both of these characteristics at a high level.

  The present invention has been made in view of the above background, and in various topcoats, in particular clear paints for automobile bodies where high scratch resistance is required, the surface hardness of the coating and scratch resistance are both achieved at a high level, An object of the present invention is to provide a copolymer which improves the appearance and design, and a leveling agent, a slipperiness imparting agent, an abrasion resistance improver and a coating composition containing the copolymer. Another object of the present invention is to provide a coated article having high surface hardness and high abrasion resistance and having a good appearance and design.

The present invention relates to the following.
[1] A copolymer (C) comprising a constituent unit derived from a macromonomer (A) and a constituent unit derived from a vinyl monomer (b),
The macromonomer (A) contains 20% by mass or more of a constitutional unit derived from the monomer (a1) having an alkyl group having 8 to 24 carbon atoms, and has a number average molecular weight of 3,500 to 10,000, and SP Value of 20 (J / cm ³ ) ^0.5 or less, and the vinyl monomer (b) contains a vinyl monomer (b1) having a hydroxyl group,
A copolymer in which the SP value of the polymer (B) obtained by polymerizing the vinyl monomer (b) is 3.5 or more larger than the SP value of the macromonomer (A).
[2] A leveling agent comprising the copolymer (C) according to the above [1].
[3] A slipperiness imparting agent comprising the copolymer (C) according to the above [1].
[4] A wear resistance improver comprising the copolymer (C) according to the above [1].
[5] A coating composition comprising the copolymer (C) according to the above [1].
[6] The coating composition according to the above [5], which further comprises a polyol resin (D) other than the copolymer (C) according to the above [1] and a polyisocyanate compound.
[7] The paint according to the above [6], wherein the difference between the SP value of the polyol resin (D) and the SP value of the polymer (B) of the monomer (b) is 1.5 or less in absolute value. Composition.
[8] A coated article obtained by coating the coating composition according to any one of the above [5] to [7] on a substrate surface.

  According to the present invention, various clear coatings, in particular clear coatings for automobile bodies where high scratch resistance is required, a copolymer that makes the coating film hardness and scratch resistance compatible at a high level, and improves the transparency, And the leveling agent containing the copolymer, a slipperiness imparting agent, an abrasion resistance improver, and a paint composition can be provided. Further, according to the present invention, it is possible to provide a coated article which is compatible with high levels of surface hardness and scratch resistance and which has good appearance and design.

Hereinafter, the copolymer, the paint composition and the coated article of the present invention will be sequentially described in detail.
The following definitions of terms apply throughout the specification and claims.

The "vinyl monomer" means a monomer having a polymerizable carbon-carbon double bond, that is, an ethylenically unsaturated bond.
The “(meth) acrylic copolymer” means a copolymer in which at least a part of the structural units is a structural unit derived from a (meth) acrylic monomer. The (meth) acrylic copolymer may further contain, for example, a structural unit derived from a monomer other than a (meth) acrylic monomer such as styrene.
The “(meth) acrylic monomer” means a monomer having a (meth) acryloyl group.
The "(meth) acryloyl group" is a generic term for acryloyl group and methacryloyl group. Similarly, “(meth) acrylate” is a generic term for acrylate and methacrylate, “(meth) acrylic acid” is a generic term for acrylic acid and methacrylic acid, “(meth) acrylonitrile” is a generic term for acrylonitrile and methacrylonitrile, “(meth) "Acrylamide" is a generic term for acrylamide and methacrylamide.

[Copolymer (C)]
The copolymer (C) of the present invention (hereinafter also referred to as “copolymer (C)”) is a structural unit derived from a macromonomer (A) described later and a structural unit derived from a vinyl monomer (b) Including. The copolymer (C) can be produced, for example, by copolymerizing the macromonomer (A) and the vinyl monomer (b).
The copolymer (C) typically has a polymer chain derived from the macromonomer (A) as a side chain, and a polymer chain mainly composed of constituent units derived from the vinyl monomer (b) as a main chain Or a block copolymer in which a polymer chain derived from the macromonomer (A) and a polymer chain composed of constituent units derived from the vinyl monomer (b) are bonded.

It is preferable that one part or all part of the structural unit which a macromonomer (A) has, and / or the structural unit derived from a vinyl monomer (b) is a structural unit derived from a (meth) acrylic-type monomer. The structural unit derived from the (meth) acrylic monomer is more preferably contained in both of the structural unit possessed by the macromonomer (A) and the structural unit derived from the vinyl monomer (b).
20-100 mass% is preferable, and, as for the ratio of the structural unit derived from the (meth) acrylic monomer in a copolymer (C), ie, the copolymerization composition of a (meth) acrylic monomer, 40-100 mass% Is more preferred.

«Macromonomer (A)»
The macromonomer (A) is a compound containing 20% by mass or more of a constituent unit derived from a monomer (a1) having an alkyl group having 8 to 24 carbon atoms (hereinafter, also referred to as “monomer (a1)”) And has an addition-reactive functional group copolymerizable with the vinyl monomer (b). As an addition reactive functional group, a radical polymerizable group is representative. When the macromonomer (A) has a radical polymerizable group, the copolymer (C) can be obtained by copolymerization of the macromonomer (A) and the vinyl monomer (b) by radical polymerization.
The addition-reactive functional group possessed by the macromonomer (A) may be other than a radically polymerizable group. When the macromonomer (A) has an addition reactive functional group other than a radical polymerizable group, the vinyl monomer (b) has a functional group capable of reacting with the addition reactive functional group Need to be included. It is also possible to obtain a copolymer (C) by reacting the functional group of the polymer consisting of the structural unit derived from the vinyl monomer (b) with the macromonomer (A) having the addition reactive functional group. it can.
Examples of the combination of the addition-reactive functional group other than the radical polymerizable group of the macromonomer (A) and the functional group capable of reacting with this functional group include, for example, the following combinations.
A combination of a hydroxyl group and a carboxyl group or an acid anhydride group.
Combination of isocyanate group and carboxyl group, hydroxyl group or thiol group.
Combination of epoxy group and amino group.
Combination of carboxyl group and epoxy group or carbodiimide group.
Combination of amino group and carboxyl group.
Combination of an amide group and a carboxyl group.
Combination of thiol group and epoxy group.

  The addition-reactive functional group possessed by the macromonomer (A) may be one or two or more, but is preferably one. The macromonomer (A) may have one or both of a radical polymerizable group and an addition reactive functional group other than the radical polymerizable group. When it has both a radically polymerizable group and an addition-reactive functional group other than a radically polymerizable group, each functional group may be one or two or more.

  The macromonomer (A) preferably has a radically polymerizable group from the viewpoint of being copolymerizable with the vinyl monomer (b). When the copolymer (C) is a copolymer of a macromonomer (A) having a radically polymerizable group and a vinyl monomer (b), a weight comprising structural units derived from the vinyl monomer (b) Compared to the reaction product of a functional group of a combination and a macromonomer having an addition-reactive functional group other than a radically polymerizable group, the amount of introduction of the macromonomer (A) can be easily controlled, and residual functional groups It is excellent at the point which can reduce the influence of the corrosion of the apparatus, etc. by the group.

The macromonomer (A) can be produced, for example, by polymerizing a monomer (a) containing 20% by mass or more of a monomer (a1) having an alkyl group having 8 to 24 carbon atoms.
As a monomer (a1), the following monomers are mentioned, for example.
2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate Hydrocarbon-containing (such as lauryl (meth) acrylate, tridecyl (meth) acrylate, hexadecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, docosyl (meth) acrylate) Meta) acrylic acid ester; monooctyl itaconate, monooctyl fumarate, "Blenmer 50 POEP-800B" (manufactured by NOF Corporation, Octoxy polyethylene glycol-polypropylene glycol-methacrylate (ethylene glycol has a chain of 8, propylene) Glycol Chain having a chain length of 6), trade names), "Blenmer 20 ANEP-600" (manufactured by NOF Corporation, nonylphenoxy (ethylene glycol-polypropylene glycol) monoacrylate, trade name), tri-n-octylsilyl (trade name) Meta) acrylate, tri-n-dodecylsilyl (meth) acrylate and the like.
As the monomer (a1), one type may be used alone, or two or more types may be used in combination. Further, at least a part of the monomer (a1) is preferably a (meth) acrylic monomer.

From the viewpoint of increasing the effect of the copolymer (C) to improve the scratch resistance and appearance of the coating film, the alkyl group having 8 to 24 carbon atoms of the monomer (a1) has a linear or branched straight chain It is preferable that it is chained. Although carbon number of the said alkyl group is 8-24, More preferably, it is 8-18, More preferably, it is 8-13. When the number of carbon atoms is 8 or more, the copolymer (C) easily covers the surface of the coating film and easily reduces the friction on the surface of the coating film, so that the abrasion resistance can be easily improved. In addition, when the carbon number of the alkyl group of the monomer (a1) is 24 or less, the handling property of the monomer (a) is improved and the production of the macromonomer (A) is facilitated.
Monomer (a1) is 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate from the viewpoint of availability. It is preferred to use stearyl (meth) acrylate.

The proportion of the structural unit derived from the monomer (a1) contained in the macromonomer (A), that is, the copolymerization composition of the monomer (a1) is 20% by mass or more. This proportion may be 100% by mass, ie a polymer of only the monomer (a1).
The copolymer composition of the monomer (a1) is 20% by mass or more, and 25% by mass or more from the viewpoint of the scratch resistance and appearance of a coating film obtained by applying a coating containing the copolymer (C). More preferably, 30% by mass or more is particularly preferable.
When the monomer (a) is polymerized to produce a solid macromonomer (A) such as spherical particles (so-called beads) or powder, the glass transition temperature of the macromonomer (A) (hereinafter referred to as Tg) Is preferably 20 ° C. or higher. From the viewpoint of recovery of the macromonomer (A), the proportion of the monomer (a1) in the monomer (a), that is, the copolymerization composition of the monomer (a1) is 80% by mass or less. 60 mass% or less is more preferable, and 50 mass% or less is especially preferable.

The macromonomer (A) may contain a constituent unit derived from a monomer other than the monomer (a1). Although various monomers can be used as monomers other than such a monomer (a1), the following monomers are mentioned, for example.
Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (meth) acrylic T-Butyl acid, isoamyl (meth) acrylate, hexyl (meth) acrylate phenyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, (meth) acrylate ) Isobornyl acrylate, 3,5,5-trimethylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyl oxyethyl (meth) acrylate, terpene Acrylates and their derivatives, hydrogenated rosin acrylates and Derivatives, hydrocarbon group-containing (meth) acrylic acid esters of;
(Meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 2-hydroxypropyl, (meth) acrylic acid 2-hydroxybutyl, (meth) acrylic acid 3-hydroxybutyl, (meth) acrylic acid 4-hydroxybutyl, Hydroxyl group-containing (meth) acrylic acid esters such as glycerol (meth) acrylate;
(Meth) acrylic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropyl hexahydrophthalic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxy Propyl phthalic acid, 2- (meth) acryloyloxyethylmaleic acid, 2- (meth) acryloyloxypropylmaleic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyl oxypropyl succinic acid, crotonic acid , Fumaric acid, maleic acid, itaconic acid, citraconic acid, monomethyl maleate, monoethyl maleate, monomethyl itaconate, monoethyl itaconate, monobutyl itaconate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, citraconic acid Carboxyl group-containing vinyl monomers such as aminoethyl;
Acid anhydride group-containing vinyl monomers such as maleic anhydride and itaconic anhydride;
(Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-t-butyl (meth) acrylamide, N-t-octyl (meth) ) Acrylamide, N-methylol (meth) acrylamide, hydroxyethyl (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone (meth) acrylamide, N, N-dimethylaminoethyl ester An amide bond-containing chain vinyl monomer such as (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N-vinylacetamide, maleic acid amide, N, N'-methylenebis (meth) acrylamide, (meth ) Acryloyl An amide bond-containing vinyl monomer such as an amide bond-containing cyclic vinyl monomer such as morpholine, N-vinylpyrrolidone, N-vinyl-ε-caprolactam, maleimide;
Unsaturated dicarboxylic acid diester monomers such as dimethyl malate, dibutyl malate, dimethyl fumarate, dibutyl fumarate, dibutyl itaconate, diperfluorocyclohexyl fumarate;
Epoxy group-containing vinyl monomers such as glycidyl (meth) acrylate, glycidyl α-ethyl acrylate and 3,4-epoxybutyl (meth) acrylate;
Amino group-containing (meth) acrylic acid ester monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate;
Divinylbenzene, ethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, diethylene glycol di ( Meta) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate DOO, dipentaerythritol hexa (meth) acrylate, allyl (meth) acrylate, triallyl cyanurate, diallyl maleate, multi-functional vinyl monomer such as polypropylene glycol diallyl ether;
Heterocyclic monomers such as vinylpyridine and vinylcarbazole;
Polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, n-butoxyethyl (meth) acrylate, isobutoxyethyl (meth) acrylate T-Butoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, nonyl phenoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, (meth) Acetoxyethyl acrylate, "Placcel FM" (manufactured by Daicel Co., Ltd., caprolactone adduct monomer, trade name), "Blenmer PME-100" (manufactured by NOF Corporation, methoxy polyethylene glycol methacrylate (ethylene glycol chain is What is 2) Trade name), "Blenmer PME-200" (manufactured by NOF Corporation, methoxy polyethylene glycol methacrylate (having a chain of ethylene glycol of 4), trade name), "Blenmer PME-400" (NOF Corporation) Product, methoxy polyethylene glycol methacrylate (the one whose chain of ethylene glycol is 9), a trade name, “Blenmer AME-100” (A trade name by NOF Corporation), “Blenmer AME-200” And glycol ester-based monomers such as “Blenmer 50 AOEP-800B” (trade name, manufactured by NOF Corporation);
3- (Meth) acryloxypropyltrimethoxysilane, 3- (Meth) acryloxypropylmethyldiethoxysilane, 3- (Meth) acryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltrimethoxysilane And silane coupling agent-containing monomers such as vinyltriethoxysilane;
Trimethylsilyl (meth) acrylate, triethylsilyl (meth) acrylate, tri-n-propylsilyl (meth) acrylate, tri-n-butylsilyl (meth) acrylate, tri-n-amylsilyl (meth) acrylate, tri-n-hexylsilyl (Meth) acrylate, triphenylsilyl (meth) acrylate, tri-p-methylphenylsilyl (meth) acrylate, tribenzylsilyl (meth) acrylate, triisopropylsilyl (meth) acrylate, triisobutylsilyl (meth) acrylate, tri -S-Butylsilyl (meth) acrylate, tri-2-methylisopropylsilyl (meth) acrylate, tri-t-butylsilyl (meth) acrylate, ethyldimethylsilyl (meth) acrylate, n-be Methyldimethylsilyl (meth) acrylate, diisopropyl n-butylsilyl (meth) acrylate, dicyclohexylphenylsilyl (meth) acrylate, t-butyldiphenylsilyl (meth) acrylate, triisopropylsilylmethyl malate, triisopropylsilyl amyl malate, Tri-n-butylsilyl-n-butylmalate, t-butyldiphenylsilylmethyl malate, t-butyldiphenylsilyl-n-butyl malate, triisopropylsilylmethyl fumarate, triisopropylsilyl amyl fumarate, tri-n-butylsilyl-n -Butyl fumarate, t-butyl diphenyl silyl methyl fumarate, t-butyl diphenyl silyl n-butyl fumarate, thyraplane FM-0711 (JNC Co., Ltd.) , Trade name), Cylaplane FM-0721 (made by JNC Co., Ltd., trade name), Cylaplane FM-0725 (made by JNC, trade name), Cylaplane TM-0701 (made by JNC Co., Ltd., merchandise) Name), Silaplain TM-0701T (made by JNC Co., Ltd., trade name), X-22-174 ASX (made by Shin-Etsu Chemical Co., Ltd., trade name), X-22-174 BX (made by Shin-Etsu Chemical Co., Ltd.) , Trade name), KF-2012 (Shin-Etsu Chemical Co., Ltd., trade name), X-22-2426 (Shin-Etsu Chemical Co., Ltd., trade name), X-22-2404 (Shin-Etsu Chemical Co., Ltd. Organosilyl group-containing monomers other than silane coupling agent-containing monomers, such as those manufactured under the trade name);
Halogenated olefins such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, chlorotrifluoroethylene and the like;
Isocyanate group-containing monomers such as (meth) acrylic acid 2-isocyanatoethyl;
2,2,2-Trifluoroethyl (meth) acrylate, 2,2,3,3,3-pentafluorophenyl (meth) acrylate, 2- (perfluorobutyl) ethyl (meth) acrylate, 3- (perfluoro) Butyl) -2-hydroxypropyl (meth) acrylate, 2- (perfluorohexyl) ethyl (meth) acrylate, 3-perfluorohexyl-2-hydroxypropyl (meth) acrylate, 3- (perfluoro-3-methylbutyl) -2-hydroxypropyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl ( Meta) methacrylate, 1 H, 1 H, 2 H, 2 H-tri Cafluorooctyl (meth) acrylate, 1H-1- (trifluoromethyl) trifluoroethyl (meth) acrylate, 1H, 1H, 3H-hexafluorobutyl (meth) acrylate, 1,2,2,2-tetrafluoro- Fluorine-containing monomers such as 1- (trifluoromethyl) ethyl (meth) acrylate (with the exception of halogenated olefins);
Monomers having an acetal structure such as 1-butoxyethyl (meth) acrylate, 1- (cyclohexyloxy) ethyl methacrylate), 2-tetrahydropyranyl (meth) acrylate;
4-methacryloyloxybenzophenone, styrene, α-methylstyrene, vinyl toluene, (meth) acrylonitrile, vinyl monomers such as vinyl chloride, vinyl acetate, vinyl propionate and the like.
When a monomer other than the monomer (a1) is used, the monomer may be one type, or two or more types.

  As a macromonomer (A), the macromonomer which has a radically polymerizable group at the terminal of the principal chain containing 2 or more structural units is preferable, and the macromonomer represented by following formula (1) is more preferable.

  In formula (1), R represents a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, an unsubstituted or substituted group Heteroaryl group having a substituent, non-aromatic or non-substituted heterocyclic group, unsubstituted or substituted aralkyl group, unsubstituted or substituted alkaryl group, unsubstituted group Or a substituted or unsubstituted organosilyl group, or an unsubstituted or substituted (poly) organosiloxane group, Q represents a main chain portion containing two or more structural units (a '), and Z represents a terminal Indicates a group.

R is the same as the ester residue which the structural unit derived from a (meth) acrylate type monomer has among the structural units of the above-mentioned macromonomer (A), and its preferable aspect is also the same.
The number of structural units constituting Q can be appropriately set such that the number average molecular weight of the macromonomer (A) falls within the above range.
As Z, for example, a hydrogen atom, a group derived from a radical polymerization initiator, a radically polymerizable group and the like can be mentioned as well as the terminal group of a polymer obtained by known radical polymerization.

  As a macromonomer (A), the macromonomer represented by following formula (2) is especially preferable.

In formula (2), R and Z are as defined in the above formula (1), R ²¹ represents a hydrogen atom or a methyl group, R ²² is an unsubstituted or substituted alkyl group, unsubstituted or substituted Group-containing alicyclic group, unsubstituted or substituted aryl group, unsubstituted or substituted heteroaryl group, unsubstituted or substituted aralkyl group, or substituted or unsubstituted group And an alkaryl group or an unsubstituted or substituted organosilyl group, each of which is a group having a radical polymerizable group, an alkyl group, an aryl group, a heteroaryl group or a non-aromatic group. Heterocyclic group, aralkyl group, alkaryl group, carboxylic acid group, carboxylic acid ester group, epoxy group, hydroxy group, alkoxy group, primary amino group Secondary amino group, tertiary amino group, an isocyanato group, sulfonic acid group is at least one carbodiimide group, selected from the group consisting of acid anhydride group and a halogen atom, n represents shows 2 or more natural number.
n is a natural number of 2 or more. n is suitably set so that the number average molecular weight (Mn) of the macromonomer (A) is 3500 or more and 10,000 or less. The preferred range of the number average molecular weight is as follows. The n R ^{21 s} may be the same or different. The n R ^{22 s} may be the same or different.

The macromonomer (A) having an addition-reactive functional group is preferably one having one or more addition-reactive functional groups and two or more of the above-described structural units (a ′). As the structural unit (a ′), one similar to the case where the macromonomer (A) has a radical polymerizable group can be used.
In addition to the macromonomer (A), a compound having a functional group can be added to a functional group of a polymer composed of a structural unit derived from a vinyl monomer (b). As an example of a compound having a functional group, X-22-173BX (Shin-Etsu Chemical Co., Ltd., product name) having an epoxy group, X-22-173DX (Shin-Etsu Chemical Co., Ltd.) having an epoxy group, Trade name) X-22-170BX having hydroxyl group (Shin-Etsu Chemical Co., Ltd., product name), X-22-170 DX having hydroxyl group (Shin-Etsu Chemical Co., Ltd., product name), X having a hydroxyl group -22-176DX (Shin-Etsu Chemical Co., Ltd. product name), X-22-176F having a hydroxyl group (Shin-Etsu Chemical Co., Ltd. product name, trade name), X-22-173 GX-A (Shin-Ekoshi) having a hydroxyl group Examples thereof include silicone compounds having a reactive group at the end such as those manufactured by Chemical Industry Co., Ltd. (trade name).

  The number average molecular weight (Mn) of the macromonomer (A) is 3,500 or more and 10,000 or less. When the number average molecular weight is 3,500 or more, it is easy to improve the scratch resistance by the copolymer (C). When the number average molecular weight is 10,000 or less, separation of the coating composition containing the copolymer (C) is less likely to occur. Moreover, it becomes easy to maintain the transparency of the coating film obtained by coating a coating composition. The number average molecular weight of the macromonomer (A) is preferably 3,500 to 8,000, more preferably 3,500 to 6,000.

  The weight average molecular weight (Mw) of the macromonomer (A) is 7,000 or more and 20,000 or less. When the weight average molecular weight is 7,000 or more, the copolymer (C) can easily improve the scratch resistance. When the weight average molecular weight is 20,000 or less, the separation of the coating composition containing the copolymer (C) hardly occurs. Moreover, it becomes easy to maintain the transparency of the coating film obtained by coating a coating composition. The weight average molecular weight of the macromonomer (A) is preferably 8,000 to 15,000, and more preferably 9,000 to 13,000.

The number average molecular weight and the weight average molecular weight of the macromonomer (A) are measured by gel filtration chromatography (GPC) using polystyrene as a reference resin.
The number average molecular weight and the weight average molecular weight of the macromonomer (A) can be adjusted by the type and amount of the polymerization initiator, chain transfer agent and the like used in the production.

The SP value of the macromonomer (A) is 20 (J / cm ³ ) ^0.5 or less. The SP value is an index quantitatively representing the compatibility of a polymer or a solvent, and is a value derived from a chemical structure. Although various calculation methods other than actual measurement of SP value have been proposed, in the present invention, R. F. Fedors, "Polymer Engineering and Science (Polym. Eng. Sci.)", (1974), 14 (2), p. 147, p. The value calculated by the method using the Fedors estimation formula described in 472 is used. Specifically, it is a value calculated using the following Fedors estimation formula.
δ = Σ (m _i δ _i )
In the above formula, [delta] is the SP value of the macromonomer (A), m _i represents the mole fraction of the monomer i constituting the macromonomer (A), [delta] _i represents the SP value of the monomer i . The unit of SP value uses (J / cm ³ ) ^0.5 . Hereinafter, the unit of SP value is omitted.

When the SP value of the macromonomer (A) is 20 or less, the copolymer (C) tends to be unevenly distributed on the surface of the coating film, and the scratch resistance of the coating film tends to be improved. The SP value of the macromonomer (A) is preferably 19 or less, more preferably 18.8 or less.
SP value can be adjusted with the copolymerization composition etc. of the monomer which forms a macromonomer (A). The (co) polymerization composition of the monomer (a1) tends to decrease the SP value as the amount increases, and by setting it to 20% by mass or more, the SP value can be easily reduced to 20 or less. Further, as monomers other than monomer (a1), i-propyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, The SP value tends to decrease by increasing the copolymer composition of isobornyl (meth) acrylate, cyclohexyl (meth) acrylate or the like, and it becomes easy to make the SP value 20 or less.

0 to 150 ° C. is preferable, 10 to 120 ° C. is more preferable, 20 to 100 ° C. is more preferable, and 30 to 60 ° C. is particularly preferable for the glass transition temperature (hereinafter also referred to as “Tg _A ”) of the macromonomer (A) . The higher the Tg _A, the more the adhesion of the coating can be suppressed. The lower the Tg _A, the more recoatability of the coating film can be ensured.
Tg _A is a polymer handbook [Polymer HandBook, J. Or. It means the value calculated by the calculation formula of Fox from the glass transition temperature and mass fraction of the homopolymer described in Brandrup, Interscience, 1989]. Note that the calculation formula of Fox is the following formula, Tg in the formula is Tg _A.
1 / (273 + Tg) = Σ (W i / (273 + Tg i))
In the formula, W _i represents the mass fraction of the monomer i, and Tg _i represents the glass transition temperature (° C.) of the homopolymer of the monomer i.

Tg _A in the case of using a monomer in which the glass transition temperature of the homopolymer is not described in the above-mentioned "polymer handbook" uses a value measured by a differential scanning calorimeter (DSC).
Tg _A can be adjusted by the copolymerization composition etc. of the monomer which forms a macromonomer (A).

Although a macromer (A) may use a commercial item, it can also use what was manufactured.
As a method for producing the macromonomer (A) having a radically polymerizable group, for example, a method of producing using a cobalt chain transfer agent, a method of using an α-substituted unsaturated compound such as α-methylstyrene dimer as a chain transfer agent, The method of using an initiator, the method of chemically bonding a radical polymerizable group to a polymer, the method by thermal decomposition, etc. are mentioned.
Among these, as a method for producing a macromonomer (A) having a radically polymerizable group, the number of production steps is small, the chain transfer constant of the catalyst used is high, and the radically polymerizable group is From the viewpoints of introduction and that the introduction rate of radically polymerizable groups into the polymer is high, etc., a method of manufacturing using a cobalt chain transfer agent is preferable. In addition, the macromonomer (A) at the time of manufacturing using a cobalt chain transfer agent has a structure represented by said Formula (1).

  Examples of the method for producing the macromonomer (A) using a cobalt chain transfer agent include aqueous dispersion polymerization methods such as bulk polymerization method, solution polymerization method, and suspension polymerization method and emulsion polymerization method. From the viewpoint of easy recovery of the macromonomer (A) produced, an aqueous dispersion polymerization method is preferred.

  As a method of chemically bonding a radically polymerizable group to a polymer to produce a macromonomer (A), for example, a halogen group of a polymer having a halogen group is used to form a radically polymerizable carbon-carbon double bond. Method of substituting with a compound having a group, a method of reacting a vinyl polymer having an acid group with a vinyl monomer having an epoxy group, a reaction of a vinyl polymer having an epoxy group and a vinyl monomer having an acid group Method, method of reacting vinyl polymer having acid group and vinyl monomer having isocyanate group, method of reacting vinyl polymer having isocyanate group and vinyl monomer having acid group, vinyl having hydroxyl group Method of reacting a polymer with a vinyl monomer having an isocyanate group, a vinyl polymer having an isocyanate group and a vinyl monomer having a hydroxyl group A method of reacting, by reacting a vinyl polymer with a diisocyanate compound having a hydroxyl group, and a method of reacting a vinyl monomer having a vinyl polymer and a hydroxyl group with the resulting isocyanate group.

  As a method for producing a macromonomer (A) having an addition-reactive functional group such as a hydroxyl group, an isocyanate group, an epoxy group, a carboxyl group, an amino group, an amido group or a thiol group, for example, a vinyl monomer having the functional group Method of copolymerizing a polymer, a method using a chain transfer agent having an addition-reactive functional group such as mercaptoethanol, mercaptoacetic acid, mercaptopropionic acid, etc., 2,2'-azobis (propane-2-carbamidine), 4, 4'-azobis (4-cyanovaleric acid), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine], 2,2'azobis [2 [1 (2 hydroxyethyl) 2 Methods using an initiator capable of introducing a functional group such as imidazoline 2-yl] propane] and the like can be mentioned.

<Vinyl monomer (b)>
The copolymer (C) contains a constituent unit derived from the vinyl monomer (b). The vinyl monomer (b) is a monomer having an ethylenically unsaturated bond other than the macromonomer (A). As a vinyl monomer (b), the thing similar to the monomer (a) demonstrated as a raw material of a macromonomer (A) can be mentioned. The vinyl monomer (b) may be used alone or in combination of two or more.
It is preferable that at least a part of the monomer (b) is a (meth) acrylic monomer.
When adding a macromonomer (A) to the polymer which consists of a structural unit derived from a vinyl monomer (b) in manufacture of a copolymer (C), a macromonomer (A) is mentioned as a vinyl monomer (b) It is preferable to include a monomer having a functional group capable of reacting with the functional group of

The copolymer (C) contains a structural unit derived from a vinyl monomer (b1) having a hydroxyl group (hereinafter also referred to as "monomer (b1)") as the vinyl monomer (b). Although various things can be used as a monomer (b1), the following monomers are mentioned, for example.
(Meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 2-hydroxypropyl, (meth) acrylic acid 2-hydroxybutyl, (meth) acrylic acid 3-hydroxypropyl, (meth) acrylic acid 3-hydroxybutyl, (Meth) acrylic acid 4-hydroxybutyl, glycerol (meth) acrylate, cyclohexane dimethanol mono (meth) acrylate, "Placcel FM" series (Caprolactone addition monomer manufactured by Daicel Corporation, trade name), "Blenmer PE" Series (NOF Co., Ltd. polyethylene glycol methacrylate, trade name), "Blenmer AE" series (NOF Co., Ltd. polyethylene glycol acrylate, trade name), "Blenmer PP" series (NOF Corp. polypropylene glycol) Methacrylate, quotient Name), "Blenmer AP" series (manufactured by NOF CORPORATION polypropylene glycol acrylate, hydroxyl group-containing (meth) acrylic acid ester of a trade name);
And hydroxyl group-containing (meth) acrylamide derivatives such as N-methylol (meth) acrylamide and hydroxyethyl (meth) acrylamide.
As the monomer (b1), one type may be used alone, or two or more types may be used in combination. Moreover, it is preferable that at least one part of a monomer (b1) is a (meth) acrylic-type monomer.

Since the copolymer (C) contains a structural unit derived from the monomer (b1) having a hydroxyl group, it reacts with the polyisocyanate compound in the paint composition and is incorporated into the crosslinked structure of the coating film. Therefore, the obtained coating film tends to have an improved scratch resistance. In addition, the copolymer (C) is less likely to be detached from the coating film.
Monomer (b1) is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (meth) acrylic acid 3 from the viewpoint of availability. -Hydroxypropyl, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate are preferably used.

The constituent ratio of the structural unit derived from the monomer (b1) is preferably 5 to 80% by mass with respect to 100% by mass of the structural unit derived from the monomer (b). As the component ratio of the monomer (b1) is larger, the copolymer (C) tends to be incorporated into the cross-linked structure of the coating film, and the scratch resistance of the coating film tends to be further improved. In addition, the copolymer (C) becomes more difficult to be detached from the coating film. On the other hand, the smaller the component ratio, the less the separation occurs when the monomer (b) and the macromonomer (A) are mixed in the production of the copolymer (C).
It is preferable that the composition ratio of the monomer (b1) be appropriately adjusted by the compounding ratio of the monomer (b) at the time of producing the copolymer (C).

  As the vinyl monomer (b) other than the monomer (b1), various monomers can be used. As such a vinyl monomer, the monomer demonstrated as a raw material of macromonomer (A) can be mentioned, for example.

  As the vinyl monomer (b), it is preferable to contain a high refractive index monomer which makes the refractive index of the homopolymer 1.5 or more. Specifically, aromatic vinyl monomers such as styrene, vinyl toluene, α-methylstyrene, etc .; phenyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydroful (meth) acrylate Furyl, isobornyl (meth) acrylate, 3,5,5-trimethylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyl (meth) acrylate Examples include alicyclic (meth) acrylates such as oxyethyl, terpene (meth) acrylate and derivatives thereof, hydrogenated rosin (meth) acrylate and derivatives thereof, adamantyl (meth) acrylate and derivatives thereof, and the like.

By including a monomer having a high refractive index, the gloss of the coating can be improved, and the design of the coating can be improved. In addition, it is possible to suppress the water absorption of the coating film or to reduce the relative dielectric constant.
The copolymerization composition of the high refractive index monomer in the copolymer (C) is preferably 10 to 60% by mass with respect to 100% by mass of the total constituent units of the copolymer (C), and is preferably 20 to 40 More preferably, it is mass%. The higher the copolymerization composition, the better the design of the coating film. On the other hand, the lower the copolymerization composition, the less the yellowing and the like of the coating film tend to occur even if the coated material is used outdoors for a long time. The copolymerization composition is preferably adjusted so that the refractive index of the copolymer (C) is 1.5 or more.

  As the high refractive index monomer, styrene, benzyl (meth) acrylate, cyclohexyl (meth) acrylate and isobornyl (meth) acrylate are preferable from the viewpoint of availability.

The vinyl monomer (b) may contain a monomer having an acid group. Although the following compounds are mentioned as a monomer which has an acidic radical, It is not limited to these.
(Meth) acrylic acid, itaconic acid, citraconic acid, maleic acid, monomethyl maleate, monobutyl maleate, monomethyl itaconate, monobutyl itaconate, vinylbenzoic acid, monohydroxyethyl (meth) acrylate oxalate, monohydroxy tetrahydrophthalic acid Ethyl (meth) acrylate, monohydroxypropyl (meth) acrylate of tetrahydrophthalic acid, monohydroxyethyl (meth) acrylate of 5-methyl-1,2-cyclohexanedicarboxylic acid, monohydroxyethyl (meth) acrylate of phthalate, monohydroxy phthalate Propyl (meth) acrylate, monohydroxyethyl (meth) acrylate maleate, hydroxypropyl (meth) acrylate maleate, monohydroxy tetrahydrophthalic acid Le (meth) acrylate.
By including a monomer having an acid group, curing of the coating composition can be accelerated.

  It is preferable that the copolymerization composition of the monomer which has an acidic radical in a copolymer (C) is 0-10 mass% with respect to 100 mass% of all the structural units of a copolymer (C). The smaller the copolymer composition, the easier it is to maintain the water resistance of the coating.

A polymer obtained by removing a structural unit derived from a monomer other than the vinyl monomer (b) from the copolymer (C), that is, a polymer (B) consisting of only the vinyl monomer (b) (hereinafter, a polymer The SP value of (B) is 3.5 or more greater than that of the macromonomer (A).
The SP value of the polymer (B) is determined in the same manner as the SP value of the macromonomer (A) described above. The SP value of the polymer (B) can be adjusted by the type and copolymerization composition of the vinyl monomer (b) in the copolymer (C).
The SP value of the polymer (B) is 3.5 or more greater than the SP value of the macromonomer (A), for example, when the SP value of the macromonomer (A) is 18.5, the polymer (B) SP value is 22 or more.
When the difference in SP value is 3.5 or more, it is considered that the part of the structural unit derived from the macromonomer (A) having an SP value of 20 or less constituting the copolymer (C) is easily oriented on the surface of the coating film . As a result, it is presumed that the coefficient of friction on the surface of the coating decreases and the scratch resistance of the coating improves.
The difference in SP value between the polymer (B) and the macromonomer (A) is preferably 3.5 to 8.0, and more preferably 3.5 to 6.0. The smaller the difference in SP value, the less likely separation occurs when the macromonomer (A) and the monomer (b) are mixed in the production of the copolymer (C). In addition, the storage stability of the obtained copolymer (C) is improved.

The (co) polymerization composition of the vinyl monomer (b) is preferably adjusted so that the glass transition temperature (Tg _B ) of the polymer ( _B ) is −40 to 80 ° C., and −20 to 60 ° C. More preferably, -10 to 45 ° C is more preferable. By setting Tg _B in such a range, the antifouling property and recoating property of the surface of the coating film containing the copolymer (C) can be easily secured.
Tg _B is the glass transition temperature of the homopolymer when the vinyl monomer (b) is one kind, and when the vinyl monomer (b) is plural kinds, according to the above-mentioned calculation formula of Fox It can be calculated.

<Contents of Constituent Units of Copolymer (C)>
In the copolymer (C), the proportion of constituent units derived from the macromonomer (A) is preferably 10 to 60% by mass, relative to 100% by mass of all constituent units of the copolymer (C), and 20 to 50% by mass Is more preferable, and 20 to 40% by mass is more preferable. As this proportion is larger, the scratch resistance of the coating film tends to be improved by the copolymer (C). On the other hand, the smaller the ratio, the less the separation of the coating composition containing the copolymer (C) occurs. Also, the less the amount, the easier it is to maintain the transparency of the coating.

  In the copolymer (C), the proportion of constituent units derived from the vinyl monomer (b) is preferably 40 to 90 mass%, relative to 100 mass% of all constituent units of the copolymer (C), and 50 to 80 Mass% is more preferable, and 60-80 mass% is further more preferable. As this ratio is larger, the compatibility and the like can be easily adjusted when the other resin is blended in the coating composition containing the copolymer (C). On the other hand, as the content is smaller, the scratch resistance of the coating film tends to be improved by the copolymer (C).

<Characteristics of copolymer (C)>
5,000-100,000 are preferable, as for the weight average molecular weight (Mw) of a copolymer (C), 8,000-50,000 are more preferable, and 10,000-30,000 are more preferable. As the weight average molecular weight of the copolymer (C) is larger, the scratch resistance of the coating film tends to be improved. On the other hand, the smaller the size, the lower the viscosity of the coating composition.
The weight average molecular weight of the copolymer (C) can be measured by gel filtration chromatography (GPC) and is a value in terms of standard polystyrene. In detail, it measures by the method as described in the Example mentioned later.

  When the copolymer (C) is a 50% by mass butyl acetate solution, the viscosity measured by a B-type viscometer at 25 ° C. (hereinafter also referred to as “solution viscosity”) is 10 to 2000 mPa · s Preferably, 100 to 1000 mPa · s is more preferable, and 100 to 700 mPa · s is more preferable. If the solution viscosity is in such a range, the coating composition containing the copolymer (C) is excellent in handleability.

<Application of Copolymer (C)>
The copolymer (C) of the present invention is used as a component other than a coating composition such as a leveling agent, a slipperiness imparting agent and an abrasion resistance improver, taking advantage of the property of being easily oriented at the interface between air and paint when painted. Can also be suitably used.

<Method of producing copolymer (C)>
The copolymer (C) can be produced, for example, by the following production method (α) or (β). The method for producing the copolymer (C) is not limited to these.
Production method (α): A method of copolymerizing the macromonomer (A) and the vinyl monomer (b) using a macromonomer having a radical polymerizable group as the macromonomer (A).
Production method (β): A macromonomer having an addition reactive functional group other than a radical polymerizable group is used as the macromonomer (A), and the macromonomer (A) and the vinyl monomer (b) described above are used. A method of reacting a polymer containing a structural unit derived from a vinyl monomer having a functional group capable of reacting with an addition-reactive functional group other than a radically polymerizable group.

  As a manufacturing method of a copolymer (C), a manufacturing method ((alpha)) is preferable. When the copolymer (C) produced by this method has a configuration unit derived from the macromonomer (A) and a component unit derived from the vinyl monomer (b) randomly arranged, that is, the copolymer (C) When a polymer chain derived from one or more macromonomers (A) is bonded throughout the main chain of C), it is called a graft polymer or a comb polymer. When the polymer chain derived from the macromonomer (A) is present only at the end of the polymer chain composed of constituent units derived from the vinyl monomer (b), it is called a block polymer. The copolymer (C) may be either a graft polymer or a block polymer, or may be a mixture thereof.

In the present invention, the copolymer composition of the copolymer (C) produced by the production method (α) is obtained by adding the feed composition of the macromonomer (A) and the vinyl monomer (b) at the time of polymerization to the copolymer composition and convenience. Call. Therefore, the preferable range of the feed composition of the monomer to be polymerized (including the macromonomer, the same applies to the following) is the same as the copolymer composition of the copolymer (C) described above.
10-60 mass% is preferable, as for the preparation composition of a macromonomer (A), 20-50 mass% is more preferable, and 20-40 mass% is further more preferable.

  In the production method (α), the polymerization of the monomer can be carried out by a known method using a known polymerization initiator. For example, there may be mentioned a method of reacting the macromonomer (A) and the vinyl monomer (b) in the presence of a radical polymerization initiator at a reaction temperature of 60 to 240 ° C. for 1 to 14 hours. At that time, a chain transfer agent may be used as needed.

As a radical polymerization initiator, although the following compounds are mentioned, it is not limited to these.
2, Azo compounds such as 2'-azobisisobutyronitrile and 2,2'-azobismethylonitrile; tertiary butyl hydroperoxide, lauroyl peroxide, benzoyl peroxide, ditertiary butyl peroxide, Peroxide compounds such as tertiary butyl peroctoate and tertiary butyl peroxy isopropyl carbonate.

In the production method (α), for example, known polymerization methods such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, and an emulsion polymerization method can be applied. As a polymerization method, a solution polymerization method using a polymerization solvent is preferable from the viewpoint of the productivity of the copolymer (C) to be produced and the ease of use as a coating composition.
This polymerization method can be carried out, for example, by supplying a polymerization solvent, a monomer and a radical polymerization initiator into a polymerization vessel and polymerizing at a predetermined reaction temperature. In this method, all of the monomers may be charged into the polymerization vessel before reaching a predetermined reaction temperature, or all of the monomers may be fed after being adjusted to a predetermined reaction temperature. Alternatively, the reaction vessel may be partially charged into a polymerization vessel before reaching a predetermined reaction temperature, and the remainder may be supplied after dropping to a predetermined reaction temperature.
Specifically, the macromonomer (A) and the polymerization solvent are charged in a polymerization container, and the vinyl monomer (b) and the radical polymerization initiator are separately dropped and supplied, for example. A method in which a solution in which both the macromonomer (A) and the vinyl monomer (b) are dissolved is dropped to the polymerization solvent charged in the polymerization vessel can be exemplified.

As a polymerization solvent which can be used for the solution polymerization method, for example, the following solvents may be mentioned.
Aromatic solvents such as toluene, xylene and other high boiling point aromatic solvents; ester solvents such as ethyl acetate, butyl acetate and cellosolve acetate; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; methyl alcohol, ethyl Alcohol solvents such as alcohol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol; SS-100 (manufactured by JXTG Energy Co., Ltd., product name), hydrocarbon solvents such as cyclohexane, and the like. The polymerization solvents may be used alone or in combination of two or more.
Among these, solvents other than aromatic solvents are preferable from the viewpoint of concentration control in the interior of buildings and automobiles. When using as a raw material of a coating composition without separating a polymerization solvent from the mixture of the copolymer (C) and the polymerization solvent obtained by the solution polymerization method, hydrocarbon solvents such as cyclohexane are used to soften the coating film, etc. It is preferable not to use as a reaction solvent in order to impair the solubility of the polyurethane etc. which are mixed with a paint constituent for the purpose.

[Coating composition]
The coating composition of the present invention comprises a copolymer (C) having a structural unit derived from the macromonomer (A) and a structural unit derived from the vinyl monomer (b). Therefore, it is easy to improve the abrasion resistance of a coating film. When the polyol resin (D) other than the copolymer (C) (hereinafter also referred to as "polyol resin (D)") is blended in the coating composition, the copolymer (C) is blended. The solubility of the polyol resin (D) tends to be improved. The reason is estimated as follows. Since the SP value of the macromonomer (A) is 3.5 or more lower than the SP value of the polymer (B) of the vinyl monomer (b), when forming a coating film, the macro of the copolymer (C) The polymer chain portion derived from the monomer (A) is hardly compatible with the main chain portion of the copolymer (C) composed of the highly polar vinyl monomer (b) and the polyol resin (D). Therefore, the portion of the polymer chain derived from the macromonomer (A) is localized on the surface side of the obtained coating film. It is presumed that the surface characteristics of the coating film are controlled by such a component gradient structure in the depth direction of the coating film.

  The coating composition can be further blended with a polyisocyanate compound (E) to form a two-component curable coating. In that case, it is preferable to contain a polyol resin (D).

«Polyol resin (D)»
The polyol resin (D) is not particularly limited as long as it has a plurality of hydroxyl groups. Examples of the polyol resin (D) include (meth) acrylic copolymers, polyester resins and polycaprolactone resins. Specifically, the resin etc. which are illustrated by patent document 1 are mentioned. A commercial item may be used as a polyol resin (D).
When a polyol resin (D) is blended in a paint composition, the polyol resin (D) may be used alone or in combination of two or more. The polyol resin (D) can improve the hardness of the coating film.

  The hydroxyl value of the polyol resin (D) is preferably 100 to 250 mg KOH / g, and more preferably 120 to 200 mg KOH / g. As the hydroxyl value is higher, the hardness of the coating film tends to be improved when crosslinking is performed by the polyisocyanate compound (E). In addition, as the hydroxyl value is lower, the water resistance of the coating film can be more easily maintained, and the storage stability of the coating composition tends to be improved.

The SP value of the polyol resin (D) largely correlates with the above-mentioned hydroxyl value, and can be adjusted by appropriately selecting the structural unit of the polyol resin. The difference between the SP value of the polyol resin (D) and the SP value of the polymer (B) consisting only of the monomer (b) constituting the copolymer (C) is preferably 1.5 or less.
The difference between the SP values of the polyol resin (D) and the polymer (B) being 1.5 or less means, for example, when the SP value of the polyol resin (D) is 23, the SP value of the polymer (B) Means that it is in the range of 21.5 to 24.5. Moreover, when SP value of a polymer (B) is 22.5, it means that SP value of a polyol resin (D) exists in the range of 21-24.
By setting the difference in SP value to 1.5 or less, the compatibility between the copolymer (C) and the polyol resin (D) tends to be improved, and the storage stability of the resulting coating composition tends to be improved. In addition, the transparency of the coating tends to be improved.

  The weight average molecular weight (Mw) of the polyol resin (D) is preferably 3,000 to 50,000. The larger the weight average molecular weight, the better the oil resistance, solvent resistance and hardness of the coating film. The smaller the weight average molecular weight, the lower the viscosity of the coating composition and the better the appearance of the coating. The weight average molecular weight is measured by gel permeation chromatography (GPC) using polystyrene as a reference resin.

«Polyisocyanate compound (E)»
The coating composition of the present invention can be blended with a polyisocyanate compound (E). The polyisocyanate compound (E) acts as a curing agent for crosslinking the copolymer (C) and the polyol resin (D).
As an isocyanate compound, polyisocyanate compounds having free isocyanate groups, blocked polyisocyanate compounds, and the like can be used. As an isocyanate compound, although the following compound is mentioned, for example, it is not limited to these.
Aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; isophorone diisocyanate, methylcyclohexane-2,4- (or 2,6-) diisocyanate, 4,4'-methylene bis (cyclohexyl isocyanate) and 1,3-di ( Cyclic aliphatic diisocyanates such as isocyanate methyl) -cyclohexane; aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate and xylene diisocyanate; adducts of the above isocyanate compounds with polyhydric alcohols, water and the like; Oligomers such as dimers and trimers of isocyanate compounds; polymers of isocyanate compounds described above; isocyanate compounds described above And an adduct comprising a polyol such as trimethylolpropane of the above-mentioned isocyanate compound. One of these may be used alone, or two or more may be used in combination.
The compounding amount of the isocyanate compound (E) in the coating composition is preferably such that the equivalent ratio NCO / OH of the isocyanate group to the hydroxyl group of the hydroxyl group-containing component is 0.1 / 1 to 3/1. .

<Other crosslinkers>
A coating composition can mix | blend other crosslinking agents other than a polyisocyanate compound (E).
When the coating composition contains a hydroxyl group-containing component, a melamine resin can be blended as another crosslinking agent. Thereby, the properties such as solvent resistance, water resistance and weather resistance of the coating can be further improved. As a melamine resin, n-butylated melamine resin, methylated melamine resin, etc. can be mentioned. The blending amount of the melamine resin is preferably 5 to 50% by mass in the coating composition.

  Further, crosslinking agents such as epoxy type, metal chelate type, photo-curing type and aziridine type can be blended. One of these crosslinking agents may be used alone, or two or more thereof may be used in combination.

  As an epoxy type crosslinking agent, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol A type epoxy resin, N, N, N ', N'-tetraglycidyl Examples thereof include -m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N-diglycidyl aniline, and N, N-diglycidyl toluidine.

  Examples of the metal chelate type crosslinking agent include compounds in which a polyvalent metal is covalently bonded or coordinated with an organic compound. Examples of the polyvalent metal include aluminum, nickel, chromium, copper, iron, tin, titanium, zinc, cobalt, manganese, zirconium and the like. Examples of the organic compound include organic compounds having an oxygen atom such as ketone compounds such as acetylacetone, alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds and the like.

The photo-curing type crosslinking agent is a compound that undergoes a crosslinking reaction by the action of a photopolymerization initiator or the like when irradiated with active energy rays such as ultraviolet rays.
As this type of crosslinking agent, for example, a polymerizable polyfunctional compound having two or more radically polymerizable groups; a polyfunctional organic resin having two or more functional groups selected from the group consisting of a glycol group, a siloxane group and an amino group; The organic metal compound etc. which have a metal complex are mentioned. Examples of the metal in the metal complex include zinc, aluminum, sodium, zirconium, calcium and the like.

  When the coating composition containing the copolymer (C) of the present invention further contains a polyol resin (D) and a polyisocyanate compound (E), the mass ratio of the copolymer (C) to the polyol resin (D) (C) / (D) is preferably 0.5 / 99.5 to 99.5 / 0.5, more preferably 3/97 to 80/20, still more preferably 5/95 to 60/40, / 90 to 40/60 is particularly preferred. As the (C) / (D) is larger, the scratch resistance of the coating film tends to be improved. On the other hand, the smaller the (C) / (D), the better the solvent resistance and hardness of the coating film.

<Organic solvent>
The coating composition of the present invention can be blended with an organic solvent as required for the purpose of improving coating suitability and film forming property.
The organic solvent is not particularly limited as long as it can dissolve the compound such as the copolymer (C). Examples of the organic solvent in the case of blending the polyol resin (D) in the coating composition include hydrocarbon solvents such as heptane, cyclohexane, toluene, xylene, octane and mineral spirit; ethyl acetate, n-butyl acetate, isobutyl acetate Ester solvents such as ethylene glycol monomethyl ether acetate and diethylene glycol monobutyl ether acetate; Ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone and cyclohexanone; methanol, ethanol, isopropanol, n-butanol, s-butanol and isobutanol Alcohol solvents; dioxane, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether and propylene glycol monopropyl Ether solvents such as ether, Cosmo Oil Co. Swasol 310, and aromatic petroleum solvents such as Swasol 1000 and Swasol 1500. These organic solvents can be used singly or in combination of two or more.

<Other optional components of coating composition>
In the paint composition of the present invention, for example, the following components can be added as an optional component, if necessary.
Well-known paint additives such as brighteners, fillers, plasticizers, pigment dispersants, thickeners, antifoaming agents and leveling agents, and softeners such as polyurethanes;
Adhesion-imparting agents for polyolefin-based substrates such as chlorinated polyolefins and maleic anhydride-modified chlorinated polyolefins;
And various additives such as reaction catalysts, tackifier resins, antioxidants, light stabilizers, metal deactivators, anti-aging agents, hygroscopic agents, rust inhibitors, and hydrolysis inhibitors.
Examples of the reaction catalyst include tertiary amine compounds, quaternary ammonium compounds, and tin laurate compounds.
Examples of the antioxidant include phenols, phosphorus, hydroxylamines and sulfurs. Among them, phenol-based and phosphoric acid-based antioxidants are preferable in that coloring of the resin after heating is small. These may be used alone or in combination of two or more. The compounding amount of the antioxidant is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass in total of the copolymer (C) and the optional polyol resin (D).

«Method of manufacturing paint composition»
The method for producing the coating composition is not particularly limited. The order of blending is preferably selected appropriately in consideration of the compatibility between the blending components of the composition in the middle stage and the finally obtained coating composition, the temporal stability of the composition, and the like.

«Applications of paint composition»
The paint composition of the present invention can be applied as a paint for various substrates. Examples of the substrate include plastic substrates and metal substrates. In addition, those substrates may be previously coated with a primer.
Specific examples of the plastic substrate include polyolefin resins such as polyethylene and polypropylene; polycarbonate resins; acrylic resins such as polymethyl methacrylate; nylon resins; and ABS resins.
Specific examples of the metal base include iron, aluminum, brass, copper, tin, stainless steel, galvanized steel, zinc alloy (such as Zn-Al, Zn-Ni and Zn-Fe) plated steel and the like.
Specific examples of the other base materials include glass, slate plates, concrete and silicate base materials such as calcium silicate; gypsum based, asbestos based and ceramic based inorganic bases; woods, papers, fibers and the like Various base materials, such as FRP, etc. are mentioned.

When the material of the substrate is a metal material, the surface of the substrate may be subjected to surface treatment such as phosphate treatment, chromate treatment and complex oxide treatment.
In addition, the surface of the substrate may be coated in advance. When the material of the substrate is a metal material, the coating may be formed on the surface of the substrate subjected to the surface treatment. As a substrate having a film formed on the surface, for example, the surface of the substrate is optionally subjected to a surface treatment to form a primer coating thereon, and an intermediate coating is further formed on the primer coating. What etc. which formed the film can be mentioned. As said undercoat, the coating film formed of electrodeposition paints, such as a cationic electrodeposition paint, is mentioned, for example.

The coating film formed from the coating composition of the present invention may be a single layer or at least one layer of a multilayer coating film, and is particularly suitable as the outermost layer of the multilayer coating film.
As the multilayer coating film, for example, a multilayer coating film consisting of (1) a colored base coating film and a clear coating film, (2) a multilayer consisting of a first colored base coating film, a second colored base coating film and a clear coating film A coating film etc. are mentioned. The coating composition of the present invention is particularly useful as a clear coating material for forming a clear coating film among the coating films of these multilayer coating films.

  The case of painting an automobile body will be described as an example of the method of forming a multilayer coating film using the coating composition of the present invention. A first colored base coating is applied to an automobile body having a cured coating of an electrodeposition coating formed on the surface to form a first colored base coating, and then the first colored base coating is not preheated. Alternatively, after preheating or heat curing, a second colored base coating is applied on the first colored base coating to form a second colored base coating, and then the first colored base coating and the second colored base coating are formed. The base coating is preheated. Thereafter, the coating composition of the present invention is applied as a clear coating on the second colored base coating film to form a clear coating film, and the formed three-layer coating film is simultaneously heat cured to form a multilayer coating film. It is a method to form. In this example, the multilayer coating film of (2) is formed on the cured coating film of the electrodeposition paint. The formation method of this multilayer coating film can be performed using the conventional method except using the coating composition of the said invention as a clear coating material.

The coating method of a plastic base material is mentioned as a formation method of other than this multilayer film. By forming the base layer with a paint composition to which a pigment is added and applying the paint composition of the present invention, a clear layer excellent in surface gloss, smoothness, and scratch resistance can be laminated. . Examples of the pigment to be added to the base layer include known organic pigments and inorganic pigments such as aluminum, titanium oxide, iron oxide, aluminum flakes, and titanium coat mica. The base layer may be preheated before forming the clear layer, or the heat curing may be completed.
The coating composition of the present invention is suitable as a coating composition for forming the outermost layer in a conventional coating film forming method.

[Painted article]
The coated article of the present invention is obtained by coating the coating composition of the present invention on the substrate surface of the article. The coating can be carried out by known methods. For example, the method of apply | coating the coating composition of this invention to a base-material surface and forming an unhardened coating film, making it harden | cure, and setting it as a cured coating film is mentioned.

The coated articles are not particularly limited, and, for example, outer plates of car bodies such as passenger cars, trucks and motorcycles, buses, etc .; automobile parts such as bumpers, handles, center consoles, instrument panels and wheels; ships and various fishing nets, Underwater structures such as port facilities, oil fences, bridges and submarine bases; household electric appliances such as mobile phones and audio equipment; outer plates of industrial machines such as agricultural machines and construction machines.
Examples of the material of the base material of the coated article include the above-mentioned metal materials and plastic materials.

  The coated article of the present invention is excellent in abrasion resistance and hardness because it has a coating film formed by applying the coating composition.

The coating method of the coating composition is not particularly limited, and known coating methods such as air spray coating, airless spray coating, rotary atomization coating, curtain coating, brush coating, dip coating, roll coating, and flow coating, for example Methods can be used. At the time of painting, electrostatic application may be performed as needed.
The film thickness of the coating film to be formed can be appropriately set and is not particularly limited. For example, the thickness of the cured coating film can be about 500 nm to 500 μm.

  The uncured coating can be cured by heating (heat curing). The heating of the uncured coating can be performed by a known heating means. As a heating means, for example, a drying furnace such as a hot air furnace, an electric furnace, an infrared induction heating furnace or the like can be used. The heating temperature is not particularly limited, but preferably about 50 to 180 ° C. The heating time is not particularly limited, but preferably about 1 to 60 minutes. It can be set according to the purpose in consideration of the evaporation rate of the thinner to be used, the drying conditions and the like.

  After coating of the coating composition, prior to heat curing, in order to prevent the occurrence of coating film defects, preheating, air blowing, etc. may be performed under heating conditions where the coating does not substantially cure. The temperature of the preheating is preferably about 30 to 100 ° C. The preheating time is preferably about 30 seconds to 15 minutes. The air blowing can be usually performed by spraying air heated to a temperature of about 30 to 100 ° C. for about 30 seconds to 15 minutes to the coated surface.

  After heat curing the coating, curing may be performed to increase the hardness of the coating. The curing conditions can be, for example, about 0 to 60 ° C. and about 1 to 10 days. During the curing, the coating film may be repaired if necessary. As the repair work, polishing by polishing means such as sand paper and buffing can be mentioned. It is preferable that the repair work be performed for three days after the start of curing.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by the following description. In addition, "part" and "%" in an Example respectively represent "mass part" and "mass%."

[Raw material of macromonomer (A) and copolymer (C)]
The raw materials of the coating composition used in the examples are as follows. The abbreviations used in Table 1 are shown below.
・ "Acryester (registered trademark) SL" manufactured by Mitsubishi Chemical Corporation (trade name, a mixture of lauryl methacrylate and tridecyl methacrylate, hereinafter referred to as "SLMA")
-"Aklyester (registered trademark) S" (trade name, stearyl methacrylate, hereinafter referred to as "SMA") manufactured by Mitsubishi Chemical Corporation.
・ "Acryoester (registered trademark) EH" (trade name, 2-ethylhexyl methacrylate, hereinafter referred to as "EHMA", manufactured by Mitsubishi Chemical Corporation)
・ "Acryoester (registered trademark) IBX" (trade name, isobornyl methacrylate, hereinafter referred to as "IBXMA") manufactured by Mitsubishi Chemical Corporation.
“Monomer (a) other than (a1)”
・ "Acryester (registered trademark) TB" (trade name, t-butyl methacrylate, hereinafter referred to as "tBMA") manufactured by Mitsubishi Chemical Corporation.
・ "Acryoester (registered trademark) M" manufactured by Mitsubishi Chemical Corporation (trade name, methyl methacrylate, hereinafter referred to as "MMA")
・ "Acryester (registered trademark) HP" manufactured by Mitsubishi Chemical Corporation (trade name: hydroxypropyl methacrylate, hereinafter referred to as "HPMA")
・ "Hydroxypropyl acrylate" (hereinafter referred to as "HPA") manufactured by Osaka Organic Chemical Industry Co., Ltd.
-Styrene (hereinafter referred to as "St")
・ "Acryoster (registered trademark) B" (trade name, n-butyl methacrylate, hereinafter referred to as "nBMA") manufactured by Mitsubishi Chemical Corporation.
Acrylic acid (hereinafter referred to as "AA")

Synthesis Example 1
(Production of Dispersant 1)
900 parts of deionized water, 60 parts of sodium 2-sulfoethyl methacrylate, 10 parts of potassium methacrylate and 12 parts of MMA in a polymerization apparatus equipped with a stirrer, condenser, thermometer and nitrogen gas inlet pipe The mixture was stirred, and the temperature in the polymerization apparatus was raised to 50 ° C. while replacing with nitrogen. Into the mixture, 0.08 parts of 2,2'-azobis (2-methylpropionamidine) dihydrochloride as a polymerization initiator was added, and the temperature was further raised to 60 ° C. After raising the temperature, MMA was continuously dropped for 75 minutes at a rate of 0.24 parts / min using a dropping pump. The reaction solution was maintained at 60 ° C. for 6 hours, and then cooled to room temperature to obtain Dispersant 1 having a solid content of 10% by mass as a clear aqueous solution.

(Production of Chain Transfer Agent 1)
In a synthesizer equipped with a stirring device, under nitrogen atmosphere, 1.00 g of cobalt (II) acetate tetrahydrate and 1.93 g of diphenylglyoxime, 80 mL of diethyl ether deoxygenated by nitrogen bubbling in advance are placed. The mixture was stirred at room temperature for 30 minutes. Then, 10 mL of boron trifluoride diethyl ether complex was added, and the mixture was further stirred for 6 hours. The mixture was filtered and the solid was washed with diethyl ether and dried under vacuum for 15 hours to give 2.12 g of chain transfer agent 1 which is a reddish brown solid.

(Manufacture of macromonomer)
145 parts of deionized water, 0.1 part of sodium sulfate and 0.25 of Dispersant 1 (10% solids by weight) in a polymerization apparatus equipped with stirrer, condenser, thermometer and nitrogen gas inlet pipe The parts were added and stirred to obtain a homogeneous aqueous solution. Next, 30 parts of SLMA, 70 parts of tBMA, 0.0020 parts of chain transfer agent 1 and Perocta (registered trademark) O (1,1,3,3-tetramethylbutyl peroxy 2-ethylhexanoate as a polymerization initiator, 0.7 part of Oil Corporation) was added to make an aqueous suspension.
Next, the inside of the polymerization apparatus was replaced with nitrogen, the temperature was raised to 80 ° C., and reaction was performed for 2 hours, and the temperature was raised to 90 ° C. and held for 1 hour in order to increase the polymerization rate. Thereafter, the reaction solution was cooled to obtain an aqueous suspension containing the macromonomer. The aqueous suspension was filtered through a filter, the residue remaining on the filter was washed with deionized water, dried and dried at 30 ° C. for 16 hours to obtain macromonomer (A-1).
The ratio of the structural unit derived from the monomer (a1) contained in the macromonomer (A-1) (denoted as "the ratio of the monomer (a1)" in Table 1) was 30 mass. The number average molecular weight of this macromonomer (A-1) was 3900, the weight average molecular weight was 9300, and the SP value was 18.5. The number average molecular weight and the weight average molecular weight were measured according to the description of “[characteristic value of copolymer solution]” described later.

Synthesis Examples 2 to 10
Macromonomers (A-2) to (A-10) were obtained in the same manner as in Synthesis Example 1 except that the monomers, chain transfer agent, and polymerization initiator were changed as shown in Table 1. The characteristic values of these macromonomers are shown in Table 1.

Example 1
40 parts of butyl acetate and 5 parts of macromonomer (A-1) are initially charged into a four-necked flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet, and the inside of the flask is It heated so that it might become temperature 120 ° C. After the internal temperature is stabilized, 15 parts of macromonomer (A-1), 40 parts of HPA, 15 parts of St, 19.5 parts of SLMA, 0.5 parts of AA, Perocta (registered trademark) O (1, 1, 3, 3) as a polymerization initiator A mixture prepared by dissolving 4 parts of 3-tetramethylbutyl peroxy 2-ethylhexanoate (manufactured by NOF Corporation) in 20 parts of butyl acetate and 10 parts of propylene glycol monomethyl ether acetate (dropwise addition) was added dropwise over 4 hours. After holding for 1 hour after completion of the dropwise addition, 0.2 part of Perocta (registered trademark) O was dissolved in 10 parts of butyl acetate and added. Then, after holding for 2 hours, it cooled to room temperature and obtained copolymer solution (C-1).
Number average molecular weight (Mn), weight average molecular weight (Mw) of the copolymer in the copolymer solution (C-1), hydroxyl value (OHV) calculated from the preparation amount of the monomer (b1), polymer ( The SP value of B) and the difference between the SP values of the polymer (B) and the macromonomer (A-1) are shown in the characteristic column of the copolymer in Table 2. Moreover, the evaluation result of the storage stability and the various characteristics of a coating film which evaluated the copolymer solution (C-1) by the method mentioned later about a coating material composition is shown in the evaluation result column of Table 2.

<Examples 2 to 6, Comparative Examples 1 to 5>
The copolymer solutions (C-2) to (C-2) to (C) were prepared in the same manner as in Example 1 except that the composition of each component to be contained in the mixture of the macromonomer in the initial preparation and the dropwise addition and the mixture in the dropwise addition was changed. C-11).
Number-average molecular weight (Mn), weight-average molecular weight (Mw) of copolymer in copolymer solution obtained in each example, hydroxyl value (OHV) calculated from preparation amount of monomer (b1), polymer ( The SP value of B) and the difference between the SP values of the polymer (B) and the macromonomer (A-1) are shown in the characteristic column of the copolymer in Table 2. Moreover, about the copolymer solution obtained by each case, the storage stability and the evaluation result of various characteristics of a coating film are shown in Table 2. However, with the copolymer solution (C-11) obtained in Example 6, the evaluation of various properties of the coating film was not performed.

[Characteristic value of copolymer solution]
(Molecular weight of macromonomer and copolymer)
The number average molecular weight (Mn) and the weight average molecular weight (Mw) of the copolymer were measured using a gel permeation chromatography (GPC) apparatus (HLC-8320, manufactured by Tosoh Corporation). A 0.2 mass% tetrahydrofuran (THF) solution of a macromonomer or copolymer is prepared, and the above-mentioned apparatus equipped with a Tosoh column (TSKgel SuperHZM-M × HZM-M × HZ2000, TSKguardcolumn SuperHZ-L) is mounted. 10 μL of the solution was injected, flow rate: 0.35 mL / min, eluent: THF (stabilizer: butylhydroxytoluene (BHT)), column temperature: measured at 40 ° C., number average molecular weight in terms of standard polystyrene ( Mn) and weight average molecular weight (Mw) were calculated.

"Storage stability"
Each copolymer solution obtained was stored in an indoor storage room at room temperature, and the state of the solution after 1 week was observed for the presence or absence of separation. The solution state was evaluated in three steps according to the following evaluation criteria.
○: Good.
Δ: Flowing in an uneven state when the stored 200 ml bottle is turned upside down.
X: Completely separated into two layers.

The copolymer solution, isocyanurate of hexamethylene diisocyanate (Duranate (registered trademark) TPA 100, manufactured by Asahi Kasei Corporation, 100% nonvolatile content, 23.1% NCO group content), NCO / OH molar ratio is 1 The paint composition was prepared by mixing so as to be 1/1.
This coating composition is coated on a black painted metal coated plate to a dry film thickness of 30 to 40 μm, predried for 5 minutes at room temperature, dried for 30 minutes in a dryer at 140 ° C. and cured for coating A film was formed, and curing was performed at a temperature of 23.5 ° C. and a relative humidity of 50%.
Seventy-two hours after the start of curing (3 days after painting), evaluation was made according to the description of "[Evaluation of coating film]" below, and the results are shown in Table 2.

[Evaluation of coating film]
"Coating film hardness"
The hardness of the coating was measured by an ultra-micro hardness tester (manufactured by Fisher Instruments, trade name: HM2000). Measurement conditions are F (test force) = 50 mN / 10 seconds, C (maximum load creep time) = 10 seconds, Martens hardness is measured at five different points of the same coating film, and their average value is used for the coating film It was hardness.

"Coat film initial gloss"
The 20 ° gloss of the coating film was measured using a gloss meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., trade name: VG7000).

"Gloss after coating abrasion" and "Abrasion resistance"
Sand paper (abrasive: aluminum oxide, mesh: 2000) was pressed against the surface of the coating, and reciprocated for 10 times with a load of 150 gf / cm ² using a Gakushin type friction tester. The 20 ° gloss of the coating after double scratch was measured and the 20 ° gloss retention before scratch was calculated.

<Production Example 1>
To a four-necked flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet, 40 parts of butyl acetate was charged as an initial charge, and heated to an internal temperature of 120 ° C. under nitrogen gas aeration. After the internal temperature is stabilized, 20 parts of St, 15 parts of MMA, 14.5 parts of 2-hydroxyethyl acrylate, 20 parts of Acryester (registered trademark) HO, 30 parts of nBMA, 0.5 parts of acrylic acid, Perocta (registered as a polymerization initiator) A mixture of 4 parts of O (1,1,3,3-tetramethylbutyl peroxy 2-ethylhexanoate, manufactured by NOF Corporation) dissolved in 20 parts of butyl acetate and 10 parts of propylene glycol monomethyl ether acetate The dropping preparation was added dropwise over 4 hours. After holding for 1 hour after completion of the dropwise addition, 0.2 part of Perocta (registered trademark) O was dissolved in 10 parts of butyl acetate and added. Then, after holding for 2 hours, it cooled to room temperature and the rior resin solution (D-1) was obtained.
The weight average molecular weight (Mw) of the copolymer in the polyol resin solution (D-1) is 12,600, and the hydroxyl value (OHV) determined from the amount of raw material monomer charged is 156 mg KOH / g, the SP value is 22 It was .5.

Examples 7-9
The copolymer solution shown in Table 3 is blended with the polyol resin solution (D-1) so that the mass ratio of the polyol resin to the copolymer is 80/20, and an isocyanurate body of hexamethylene diisocyanate (Duranate (registered trademark) A coating composition was prepared by mixing TPA 100, manufactured by Asahi Kasei Corp., nonvolatile content 100%, NCO group content 23.1%, so that the molar ratio of NCO / OH was 1/1.
This coating composition is coated on a black painted metal coated plate to a dry film thickness of 30 to 40 μm, predried for 5 minutes at room temperature, dried for 30 minutes in a dryer at 140 ° C. and cured for coating A film was formed, and curing was performed at a temperature of 23.5 ° C. and a relative humidity of 50%.
Seventy two hours after the start of curing (3 days after painting), evaluation was made according to the description of the above-mentioned "[Evaluation of coating film]", and the respective results are shown in Table 3.

As shown in Table 2, the copolymer solutions of Examples 1 to 5 are excellent in storage stability, and the coating film of the coating composition prepared using the copolymer solution has the hardness and scratch resistance of the coating film. It was compatible at a high level, and the initial gloss was high.
The coating film using the copolymer solution of Comparative Example 1 in which the number average molecular weight of the macromonomer is small was inferior in the scratch resistance.
The copolymer solution of Comparative Example 2 in which the number average molecular weight of the macromonomer was large was inferior in storage stability, and the transparency of the coating film using this was also low.
The coating film using the copolymer solution of Comparative Example 3 in which the SP value of the macromonomer is large was inferior in the scratch resistance.
The coating film using the copolymer solution of Comparative Example 4 using a macromonomer having a small content of the alkyl group-containing monomer having 8 to 24 carbon atoms was inferior in the scratch resistance.
The coating film using the copolymer solution of Comparative Example 5 which used the macromonomer which does not contain a C8-C24 alkyl group containing monomer was inferior to abrasion resistance.

  As shown in Table 2, the copolymer solution (C-11) of Example 6 was excellent in storage stability. Moreover, as shown in Table 3, the coating film formed using the coating composition of Examples 7 to 9 including the copolymer solution obtained in Example 1, 5 or 6 has a high initial gloss, and the coating film Both hardness and abrasion resistance were compatible at a high level.

Claims (8)

A copolymer (C) comprising a constituent unit derived from a macromonomer (A) and a constituent unit derived from a vinyl monomer (b),
The macromonomer (A) contains 20% by mass or more of a constitutional unit derived from the monomer (a1) having an alkyl group having 8 to 24 carbon atoms, and has a number average molecular weight of 3,500 to 10,000, and SP Value of 20 (J / cm ³ ) ^0.5 or less, and the vinyl monomer (b) contains a vinyl monomer (b1) having a hydroxyl group,
A copolymer in which the SP value of the polymer (B) obtained by polymerizing the vinyl monomer (b) is 3.5 or more larger than the SP value of the macromonomer (A).   A leveling agent comprising the copolymer (C) according to claim 1.   A slipperiness imparting agent comprising the copolymer (C) according to claim 1.   An abrasion resistance improver comprising the copolymer (C) according to claim 1.   A coating composition comprising the copolymer (C) according to claim 1.   The coating composition according to claim 5, further comprising a polyol resin (D) other than the copolymer (C) according to claim 1 and a polyisocyanate compound.   The coating composition according to claim 6, wherein the difference between the SP value of the polyol resin (D) and the SP value of the polymer (B) is 1.5 or less in absolute value.   A coated article obtained by coating the coating composition according to any one of claims 5 to 7 on a substrate surface.