RHEOLOGY AND PAINT COMPOSITION CONTROL AGENT.

Abstract

A rheology control agent contains a reaction product of a polyisocyanate compound (a1), a primary monoamine having a number-average molecular weight of 300 or less (a2), and a polyetheramine having two or more amino groups and having a number-average molecular weight of 1000 or more and less than 6000 (a3), wherein the proportion of polyetheramine having a number-average molecular weight of 1000 or more and less than 6000 (a3) ​​is within the range of 10 to 30% by mass based on the total amount of components (a1) to (a3).

Description

(54) Title: RHEOLOGY AND PAINT COMPOSITION CONTROL AGENT. (54) Title: VISCOSITY MODIFIER AND PAINT COMPOSITION. (57) Summary A rheology control agent contains a reaction product of a polyisocyanate compound (a1), a primary monoamine having a number-average molecular weight of 300 or less (a2), and a polyetheramine having two or more amino groups and having a number-average molecular weight of 1000 or more and less than 6000 (a3), wherein the proportion of polyetheramine having a number-average molecular weight of 1000 or more and less than 6000 (a3) ​​is within the range of 10 to 30% by mass based on the total amount of components (a1) to (a3). (57) Abstract This viscosity modifier contains a reaction product of: a polyisocyanate compound (a1); a primary monoamine (a2) having a number-average molecular weight of 300 or lower; and a polyether amine (a3) ​​having two or more amino groups and having a number-average molecular weight of about 1,000-6,000 (exclusive of 6,000), wherein a blending proportion of the polyether amine (a3) ​​having a number-average molecular weight of about 1,000-6,000 (exclusive of 6,000) ¡s within a range of about 10-30 mass% with respect to the total amount of the components (a1) to (a3). RHEOLOGY AND PAINT COMPOSITION CONTROL AGENT TECHNICAL FIELD OF THE INVENTION The present invention relates to a rheology control agent and a paint composition. BACKGROUND OF THE INVENTION To impart excellent appearance and properties to a substrate, a coating film is conventionally formed over the substrate by applying a paint composition to the substrate to form a wet coating film and curing the wet coating film. However, when the substrate has a vertical plane, the wet coating film on the vertical plane buckles, resulting in a poor appearance of the coating film. To solve this problem, a paint composition containing a rheology control agent (rheology controller) with buckling control capabilities has been investigated. For example, PTL1 describes a paint composition containing a binder component and a rheology control agent; and the rheology control agent for use contains a reaction product of a polyisocyanate compound, a primary monoamine having a number-average molecular weight of 300 or less, and a polyetheramine having a number-average molecular weight of more than 300 and less than 6000. List of appointments Patent literature PTL 1: WO2018 / 012552A BRIEF DESCRIPTION OF THE INVENTION Technical problem The coating film formed from the paint composition described in PTL 1 is excellent in transparency, water resistance, and finished appearance. However, there is room for further improvement in sag resistance during coating, and in the final appearance and reddening resistance of the resulting coating film. The present invention was made in view of the aforementioned current state. An object of the present invention is to provide a rheology control agent usable for producing a paint composition excellent in sag resistance during coating, finished appearance, and water reddening resistance, hereinafter referred to as water reddening resistance, of the resulting coating film. Solution to the problem The present inventors carried out extensive research to achieve the objective and found that the objective can be achieved by means of a rheology control agent containing a reaction product of a polyisocyanate compound (a1), a primary monoamine having a number-average molecular weight of 300 or less (a2), and a polyetheramine having two or more amino groups and having a number-average molecular weight of 1000 or more and less than 6000 (a3), wherein the proportion of polyetheramine having a number-average molecular weight of 1000 or more and less than 6000 (a3) ​​is within the range of 10 to 30% by mass based on the total amount of components (a1) to (a3). Specifically, the present invention includes the following subject matter. In one embodiment, a rheology control agent is provided containing a reaction product of a polyisocyanate compound (a1), a primary monoamine having a number-average molecular weight of 300 or less (a2), and a polyetheramine having two or more amino groups and having a number-average molecular weight of 1000 or more and less than 6000 (a3), wherein the proportion of polyetheramine having a number-average molecular weight of 1000 or more and less than 6000 (a3) ​​is within the range of 10 to 30% by mass based on the total amount of components (a1) to (a3). In another form, the polyether amine (a3) ​​has three or more amino groups. In another embodiment, the proportion of polyether amine (a3) ​​is more than 15% by mass and 30% by mass or less based on the total amount of components (al) to (a3). In one embodiment, a paint composition is provided that contains the rheology control agent of any of the above elements and a binder component (B). In another embodiment, the binding component (B) contains a resin containing hydroxyl (B1) and a crosslinking agent (B2). Advantageous effects of the invention The paint composition containing the rheology control agent of the present invention forms a coating film with excellent resistance to sagging during coating, and a finished appearance and resistance to reddening of the resulting coating film. DETAILED DESCRIPTION OF THE INVENTION nzoAnn / ίζηζ / Β / γίΛΐ The rheology control agent of the present invention is described in more detail below. Rheology control agent (A) In general, it is preferable for a paint composition to have low viscosity when the shear rate is high, such as during atomization, and high viscosity when the shear rate is low, such as during coating (e.g., by a coating method such as air spray coating, airless spray coating, rotary atomizing coating, etc.). This is because such a paint composition can form a coating film with an excellent appearance. Specifically, a paint with a viscosity that decreases with increasing shear rate is preferable. A rheology control agent is a component added to a paint composition to develop the desired viscosity.The rheology control agent of the present invention contains a reaction product of (a1) a polyisocyanate compound, (a2) a primary monoamine having a number-average molecular weight of 300 or less, and (a3) ​​a polyetheramine having two or more amino groups and having a number-average molecular weight of 1000 or more and less than 6000, wherein the proportion of polyetheramine having a number-average molecular weight of 1000 or more and less than 6000 (a3) ​​is within the range of 10 to 30% by mass based on the total amount of components (a1) to (a3). Polyisocyanate compound (al) A polyisocyanate compound is a compound that has at least two isocyanate groups per molecule. Examples include aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, aromatic-aliphatic polyisocyanate compounds, aromatic polyisocyanate compounds, derivatives of these polyisocyanate compounds, and the like. Examples of aliphatic polyisocyanate compounds include aliphatic diisocyanate compounds, such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, dimeric acid diisocyanate, and methyl 2,6-diisocyanatehexanoate (common name: lysine diisocyanate); aliphatic triisocyanate compounds, such as 2,6-ethyl 2-isocyanatohexanoate, 1,6-diisocyanato-3-isocyanatomethylhexane, 1,4,8-triisocyanatooctane, 1,6,11-triisocyanatoundecane, 1,8-diisocyanato-4-isocyanatomethyl, 1,3,6-triisocyanatohexane and 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanatomethyloctane; and the like. Examples of alicyclic polyisocyanate compounds include alicyclic diisocyanate compounds, such as 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isodanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (common name: isophorone diisocyanate), 4-methyl-1,3-cyclohexylene diisocyanate (common name: hydrogenated TDI), 2-methyl-1,3-cyclohexylene diisocyanate, 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane (common name: hydrogenated xylylene diisocyanate) or mixtures thereof, and methylenebis(4,l-d-chlorohexanediyl)diisocyanate (common name: hydrogenated MDI) and norbornane diisocyanate; alicyclic triisocyanate compounds, such as 1,3,5-triisocyanatocyclohexane, 1,3,5-trimethylisocyanatocyclohexane, 2-(3-isocyanatopropyl)-2,5-di(isocyanatomethyl)-bicyclo(2.2.1)heptane, 2-(3-isocyanatopropyl)-2,6-di(isocyanatomethyl)bicyclo(2.2.1)heptane, 3-(3-isocyanatopropyl)-2,5-di(isocyanatomethyl)-bicyclo(2.2.1)heptane.l)heptane, 5-(2-isocyanatoethyl)-2isocyanatomethyl-3-(3-socyanatopropyl)-biddo(2.2.1)heptane, 6-(2-isocyanatoethyl)-2-isocyanatometü-3-(3-isocyanatopropyl)-bicyclo(2.2.1)heptane, 5-(2-socyanatoethyl)-2-isocyanatomethyl·2-(3-socyanatopropyl)bidclo(2.2. l)heptane and 6-(2-socyanatoethyl)-2-isocyanatomethyl-2-(3-socyanatopropyl)-bicyclo(2.2. l)heptane; and the like. Examples of aromatic-aliphatic polyisocyanate compounds include aromatic-aliphatic diisocyanate compounds, such as methylenebis(4,1-phenylene)diisocyanate (common name: MDI), 1,3- or 1,4-xylylene diisocyanate or mixtures thereof, CO,Cl>'-diisocyanate-1,4-diethylbenzene and 1,3-ol,4-bis(1-isocyanate-1-methylethyl)benzene (common name: tetramethylxylylene diisocyanate) or mixtures thereof; aromatic-aliphatic triisocyanate compounds, such as 1,3,5-triisocyanatemethylbenzene; and the like. Examples of aromatic polyisocyanate compounds include aromatic diisocyanate compounds, such as m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 2,4-tolylene diisocyanate (common name: 2,4-TDI) or 2,6-tolylene diisocyanate (common name: 2,6-TDI) or mixtures thereof, 4,4'-toluidine diisocyanate and 4,4'-diphenyl ether diisocyanate; aromatic triisocyanate compounds, such as triphenyllmethane-4,4',4-triisocyanate, 1,3,5-triisocyanatobenzene and 2,4,6-triisocyanatotoluene; aromatic tetraisocyanate compounds, such as 4,4'-diphenylmethane-2,2',5,5'-tetraisocyanate; and the like. Examples of derivatives of polyisocyanate compounds include dimers, trimers, biurets, allophanates, urethdiones, urethymine, isocyanurates, oxadiazinetriones, polymethylene polyphenyl polyisocyanates (crude MDI, polymeric MDI), crude TDI and the like, of the polyisocyanate compounds mentioned above. The above polyisocyanate compounds and their derivatives can be used individually or in a combination of two or more. The polyisocyanate compound (al) is preferably an aliphatic polyisocyanate compound and / or a derivative thereof, more preferably an aliphatic diisocyanate compound and / or an isocyanurate thereof, from the standpoint of sagging resistance during coating, water reddening resistance, and the final appearance of the resulting coating film. Of these, hexamethylene diisocyanate and / or an isocyanurate thereof are preferred, and hexamethylene diisocyanate is most preferred. Primary monoamine that has a number average molecular weight of 300 or less (a2) Examples of primary monoamines having a number-average molecular weight of 300 or less (a2) include benzylamine, ethylamine, n-propylamine, sec-propylamine, n-butylamine, sec-butylamine, n-pentylamine, α-methylbutylamine, α-ethylpropylamine, β-ethylbutylamine, hexylamine, octylamine, 2-ethylhexylamine, n-decylamine, 1-aminooctadecane (stearylamine), cyclohexylamine, aniline, 2-(2-aminoethoxy)ethanol, and the like. These primary monoamines (a2) may be used alone or in combination with one or more others. Since the primary monoamine has a number-average molecular weight of 300 or less (a2), a primary monoamine containing a benzene ring is preferable, and benzylamine is most preferable, from the point of view of sagging resistance during coating, and resistance to water reddening and finished appearance of the resulting coating film. The number average molecular weight of the primary monoamine having a number average molecular weight of 300 or less (a2) is within the range of preferably 60 to 300, more preferably 75 to 250, and even more preferably 90 to 150, from the point of view of resistance to sagging during coating, and resistance to water reddening and the final appearance of the resulting coating film. Polyether amine (a3) The polyether amine (a3) ​​is a polyether that has two or more ether linkages per molecule, and is an amine that has two or more amino groups and a number average molecular weight of 1000 or more and less than 6000. In particular, the number average molecular weight of the polyether amine (a3) ​​is within the range of preferably 1000 to 5000, more preferably 2000 to 5000, and even more preferably 2000 to 4000, from the point of view of buckling resistance during coating, and resistance to water reddening and the final appearance of the resulting coating film. From the point of view of buckling resistance during coating, and resistance to water reddening and the final appearance of the resulting coating film, polyether amine (a3) ​​is preferably a primary amine. Polyetheramine (a3) ​​has two or more amino groups. From the standpoint of sagging resistance during coating, water reddening resistance, and the final appearance of the resulting coating film, polyetheramine (a3) ​​is most preferably at least one amine selected from the group consisting of a diamine and a triamine, and particularly preferably a triamine. Therefore, from the standpoint of buckling resistance during coating, water reddening resistance, and the final appearance of the resulting coating film, the polyether amine (a3) ​​is preferably at least one amine selected from the group consisting of a primary diamine and a primary triamine, and more preferably a primary triamine. In the present invention, the primary diamine is an amine having two -NH2 groups, and the primary triamine is an amine having three -NH2 groups. As polyether amine (a3), for example, an amine containing polyoxyalkylene can preferably be used. From the point of view of buckling resistance during coating, and resistance to water reddening and the final appearance of the resulting coating film, at least one amine compound selected from the group consisting of a polyoxyalkylene-containing diamine represented by formula (1) below (a3-1) and a polyoxyalkylene-containing polyamine having three or more amino groups represented by formula (4) below (a3-2) may be used preferably as the polyoxyalkylene-containing amine. Of these, the polyamine containing polyoxyalkylene having three or more amino groups (a3-2) may be particularly preferred from the point of view of sagging resistance during coating, and resistance to water reddening and the final appearance of the resulting coating film. nzo«nn / Lznz / B / YiAi Diamine containing polyoxyalkylene (a3-l) The polyoxyalkylene-containing diamine (a3-l) is a polyoxyalkylene-containing diamine represented by formula (1) below. H2N—R3—lo—R4-|---NH2(l)L Jn (where R3 represents a C2-6 alkylene group, preferably a C24 alkylene group, more preferably at least one alkylene group selected from the group consisting of an ethylene group, a propylene group, and a tetramethylene group; R4 represents a C2-6 alkylene group, preferably a C24 alkylene group, more preferably at least one alkylene group selected from the group consisting of an ethylene group, a propylene group, and a tetramethylene group; n represents an integer from 9 to 134, preferably 27 to 112, more preferably 27 to 89; n oxyalkylene (O-R4) units may be the same or different; when the oxyalkylene (O-R4) units are different from each other, the addition mode (polymerization mode) of the oxyalkylene (O-R4) units may be a random mode or a block shape). Specifically, as the polyoxyalkylene-containing diamine (a3-l), a polyoxyalkylene-containing diamine represented by formula (2) below H2N VNH2(2) ' z ch3ch3 (where c represents an integer from 16 to 102, preferably from 33 to 85, and more preferably from 33 to 68) and / or a polyoxyalkylene-containing diamine represented by formula (3) below CH3ch3ch3nzo«nn / ίζηζ / Β / γίΛΐ (where d and f each represent an integer from 1 to 20, preferably from 2 to 15, more preferably from 2 to 10; e represents an integer from 12 to 60, preferably from 15 to 50, more preferably from 25 to 45; d+f is within the range of 2 to 40, in particular, preferably 4 to 30, more preferably 4 to 20, even more preferably 4 to 18) may be used preferably. A commercially available product as a diamine containing polyoxyalkylene (a3-l) may be used. Examples of commercially available products include JEFFAMINE D-2000 (number average molecular weight: 2000; in formula (2) above, c ~ 33), JEFFAMINE D-4000 (number average molecular weight: 4000; in formula (2) above, c ~ 68), and JEFFAMINE ED-2003 (number average molecular weight: 2000; in formula (3) above, d + f ~ 6, e ~ 39), EtASTAMINE RT-1000 (number average molecular weight: 1000). Polyamine containing polyoxyalkylene (a3-2) The polyoxyalkylene-containing polyamine (a3-2) is a polyoxyalkylene-containing polyamine having three or more amino groups represented by the formula (4) below. (4) (where R5 represents a q-valent organic group having a carbon atom at a bonding site with the oxygen atom indicated in the formula, preferably a q-valent hydrocarbon group; R6 represents a Cm alkylene group, preferably a Cm alkylene group, more preferably at least one alkylene group selected from the group consisting of an ethylene group, a propylene group and a tetramethylene group; p represents an integer from 4 to 45, preferably 10 to 40, more preferably 15 to 30; q represents an integer of 3 or more, preferably from 3 to 6, more preferably 3 or 4; p oxyalkylene (O-R6) units may be the same or different; when the oxyalkylene (O-R6) units are different from each other, the addition mode (polymerization mode) of the oxyalkylene (O-R6) units may be a random mode or a block mode). Specifically, as a polyoxyalkylene-containing polyamine (a3-2), a polyoxyalkylene-containing triamine represented by formula (5) below nzopnn / ίζηζ / ε / γίΛΐ (where j, kyr each represent an integer from 5 to 60, preferably from 10 to 50, more preferably from 10 to 0; in particular, it is preferred that j+k+r be within the range of 17 to 102, preferably 33 to 86, and more preferably 33 to 68) may be used preferably. A commercially available polyamine containing polyoxyalkylene (a3-2) may be used. Examples of commercially available products include JEFFAMINE T-3000 (number average molecular weight: 3000; in formula (5) above, j+k+r ~ 50) and JEFFAMINE T-5000 (number average molecular weight: 5000; in formula (5) above, j+k+r ~ 85). Reaction method The reaction of the polyisocyanate compound (a1), the primary monoamine having a number-average molecular weight of 300 or less (a2), and the polyetheramine (a3) ​​can generally be carried out by mixing the components (a1) and (a3) ​​according to any selected method at, if necessary, elevated temperature. The reaction is carried out at a temperature preferably of 5 to 80°C, and more preferably of 10 to 60°C. Through this reaction, the carbonyls of the polyisocyanate compound (a1) and the amines of the primary monoamine having a number average molecular weight of 300 or less (a2) and the polyether amine (a3) ​​form urea bonds, resulting in the formation of a cross-linked structure. Typically, components (al) to (a3) ​​can be mixed by any selected method. For example, components (al) to (a3) ​​can be mixed by simultaneously adding a mixture of the primary monoamine (a2) and the polyetheramine (a3) ​​and the polyisocyanate compound (al) dropwise to a reaction vessel, or by adding the polyisocyanate compound (al) dropwise to a mixture of the primary monoamine (a2) and the polyetheramine (a3). If necessary, the components can be mixed in several stages. The reaction of components (al) to (a3) ​​is preferably carried out in the presence of an organic solvent. Examples of organic solvents include toluene, xylene, Swasol 1000 (trade name, produced by Cosmo Oil Co., Ltd., an oil-based high-boiling solvent) and similar aromatic solvents; mineral alcohol and similar aliphatic solvents; ethyl acetate, butyl acetate, propyl propionate, butyl propionate, l-methoxy-2-propyl acetate, 2-ethoxyethyl propionate, 3-methoxybutyl acetate, ethylene glycol acetate ethyl ether, propylene glycol acetate methyl ether and similar ester-based solvents; methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone and similar ketone-based solvents; isopropanol, n-butanol, isobutanol, 2-ethylhexanol and similar alcohol-based solvents; and the like. With regard to the ratio of components (al) to (a3) ​​when reacting components (al) to (a3), the proportion of polyetheramine (a3) ​​is within the range of 10 to 30% by mass based on the total amount of components (al) to (a3) ​​from the point of view of buckling resistance during coating, and resistance to water reddening and the final appearance of the resulting coating film. Following the reaction of components (al) to (a3), the proportions of components (al) to (a3) ​​are preferably within the following ranges based on the total amount of components (al) to (a3) ​​from the point of view of sagging resistance during coating, water reddening resistance and the final appearance of the resulting coating film: Polyisocyanate compound (al): 30 to 60% by mass, preferably 30 to 55% by mass, and more preferably 30 to 45% by mass; Primary monoamine having a number average molecular weight of 300 or less (a2): 30 to 60% by mass, preferably 35 to 60% by mass, and more preferably 35 to 55% by mass; and Polyetheramine (a3): 10 to 30% by mass, preferably more than 15% by mass and 30% by mass or less, and more preferably 18 to 28% by mass. Following the reaction of components (al) to (a3), the ratio of the total number of amino groups in the primary monoamine (a2) and polyetheramine (a3) ​​to the number of isocyanate groups in the polyisocyanate compound (al) (amino groups / isocyanate groups) is within the range of preferably 0.7 to 1.5, more preferably 0.9 to 1.1, and even more preferably 0.95 to 1.05, from the point of view of sagging resistance during coating, and resistance to water reddening and the final appearance of the resulting coating film. In the present invention, the rheology control agent (A) may contain a reaction product of the polyisocyanate compound (a1) and the primary monoamine (a2), or a reaction product of the polyisocyanate compound (a1) and the polyetheramine (a3), other than the reaction product of the polyisocyanate compound (a1), the primary monoamine (a2) and the polyetheramine (a3). Furthermore, the reaction of components (al) to (a3) ​​is preferably carried out in the presence of a resin component, from the point of view of suppressing the aggregation of the reaction product. Examples of resin components include acrylic resins, polyester resins, polyether resins, polycarbonate resins, polyurethane resins, epoxy resins, alkyd resins, and the like. Of these, acrylic resins are preferable in terms of sagging resistance during coating, resistance to water reddening, and the final appearance of the resulting coating film. The resin component may be a binder component (B), described later, or a resin component that is different from the binder component (B).Preferably, a film-forming resin, such as a hydroxy-containing secondary acrylic resin (Bl-la), described below, other than a hydroxy- and alkoxysilyl-containing acrylic resin (Bl-lb), described below, and a hydroxy- and alkoxysilyl-containing secondary acrylic resin (Bl-lc), described below, is used as the resin component. When the reaction of components (al) to (a3) ​​is carried out in the presence of the resin component mentioned above, the mixing ratio of components (al) to (a3) ​​and the resin component is preferably such that the ratio of the total mass of components (al) to (a3) ​​to the mass of the resin component, i.e., the ratio (the total mass of components (al) to (a3)) / (the mass of the resin component), is within the range of 1 / 99 to 15 / 85, and preferably 2 / 98 to 12 / 88. Paint composition The paint composition of the present invention (hereafter sometimes referred to simply as the paint of the present invention) is a paint composition containing the theology control agent (A) and the binder component (B). Binding component (B) The binder component (B) itself has film-forming properties. The binder component (B) may be non-crosslinkable or crosslinkable. In particular, the binder component (B) is preferably crosslinkable. A known film-forming resin that has been used as a binder component for paint may be used as the binder component (B). Examples of film-forming resins include acrylic resins, polyester resins, alkyd resins, polyurethane resins, and similar compounds. Film-forming resins preferably contain a crosslinkable functional group, such as hydroxy, carboxy, or epoxy. In addition to the film-forming resin, a crosslinking agent can also be used as the binder component (B). When a crosslinking agent is used as part of the binder component (B), a resin (a base resin) containing a crosslinkable functional group, such as hydroxy, carboxy, or epoxy, and capable of forming a crosslinked coating film by reaction with the crosslinking agent, can generally be used as the film-forming resin. From the standpoint of, for example, the water resistance of the resulting coating film, the paint composition of the present invention is preferably a crosslinkable paint containing the base resin and the crosslinking agent. In particular, the paint composition of the present invention preferably contains a resin containing hydroxyl (B1) as at least a part of the base resin, and a crosslinking agent (B2) reactive with the resin containing hydroxyl as at least a part of the crosslinking agent. Resin containing hydroxy (Bl) A hydroxyl-containing (Bl) resin is a resin that has at least one hydroxyl group per molecule. Various resins known as hydroxyl-containing (Bl) resins can be used. Examples include hydroxyl-containing acrylic resins, hydroxyl-containing polyester resins, hydroxyl-containing acrylic-modified polyester resins, hydroxyl-containing polyether resins, hydroxyl-containing polycarbonate resins, hydroxyl-containing polyurethane resins, hydroxyl-containing epoxy resins, hydroxyl-containing alkyd resins, and similar resins. These can be used alone or in combination. In particular, from the standpoint of, for example, the water resistance of the resulting coating film, a hydroxyl-containing (Bl) resin is preferably a hydroxyl-containing (Bl-1) acrylic resin. Acrylic resin containing hydroxy (Bl-1) The acrylic resin containing hydroxyl (Bl-1) can be obtained, for example, by copolymerizing a polymerizable unsaturated monomer containing hydroxyl and another polymerizable unsaturated monomer (a polymerizable unsaturated monomer other than the polymerizable unsaturated monomer containing hydroxyl). A polymerizable unsaturated monomer containing hydroxyl is a compound that contains one or more hydroxyl groups and one or more polymerizable unsaturated bonds per molecule. Examples of polymerizable unsaturated monomers containing hydroxyl include monoesterified products of (meth)acrylic acid with a dihydric alcohol having 2 to 8 carbon atoms (e.g., 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate); ε-caprolactone-modified products of such monoesterified products of (meth)acrylic acid with a dihydric alcohol having 2 to 8 carbon atoms; and adducts of (meth)acrylic acid with an epoxy-containing compound (e.g., Cardura E10P, trade name, produced by Momentive Specialty Chemicals Inc.)., glycidyl ester of neodecanoic acid); N-hydroxymethyl (meth)acrylamide; allyl alcohol; (meth)acrylates including a polyoxyethylene chain terminated in hydroxy; and the like. As another polymerizable unsaturated monomer copolymerizable with the polymerizable unsaturated monomer containing hydroxyl, for example, the monomers listed in (1) to (6) below may be used. These polymerizable unsaturated monomers may be used individually or in a combination of two or more. (1) Polymerizable unsaturated monomers containing acid groups A polymerizable unsaturated monomer containing an acid group is a compound that has one or more acid groups and one or more polymerizable unsaturated bonds per molecule. Examples of such monomers include carboxy-containing monomers, such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, and maleic anhydride; sulfonic acid-containing monomers, such as vinylsulfonic acid and 2-sulfoethyl (meth)acrylate; and acid phosphate monomers, such as 2-(meth)acryloyloxyethyl acid phosphate, 2-(meth)acryloyloxypropyl acid phosphate, 2-(meth)acryloyloxy-3-chloropropyl acid phosphate, and 2-methacryloyloxyethylphenyl phosphoric acid. These monomers can be used individually or in a combination of two or more. When using a polymerizable unsaturated monomer containing an acid group, the monomer is preferably used in an amount such that the hydroxyl-containing acrylic resin (B1-1) has an acidity value of 0.5 to 15 mg of KOH / g more preferably 1 to 10 mg of KOH / g. (2) Esterified products of acrylic acid or methacrylic acid with a monohydric alcohol having from 1 to 20 carbon atoms. Specific examples include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, n-butyl(meth)acrylate, iso-butyl(meth)acrylate, tert-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, isooctyl (meth)acrylate, isomistyl (meth)acrylate, stearyl (meth)acrylate, isostearyl acrylate (trade name, produced by Osaka Organic Chemical Industry, Ltd.), lauryl (meth)acrylate, tridecyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and the like. (3) Aromatic vinyl monomers Specific examples include styrene, α-methylstyrene, vinyltoluene, and similar substances. When an aromatic vinyl monomer is used as a constituent component, the glass transition temperature of the resulting resin is raised, and a hydrophobic coating film with a high refractive index can be obtained. This provides an enhanced finish due to the increased gloss of the coating film. When an aromatic vinyl monomer is used as a constituent component, its proportion is preferably in the range of 3 to 50% by mass, and particularly preferably from 5 to 40% by mass, based on the total amount of monomeric components. (4) Polymerizable unsaturated monomers containing glycidyl groups A polymerizable unsaturated monomer containing a glycidyl group is a compound that has one or more glycidyl groups and one or more polymerizable unsaturated bonds per molecule. Specific examples include glycidyl acrylate, glycidyl methacrylate, and similar compounds. (5) Compounds containing nitrogen and a polymerizable unsaturated bond Examples include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-[3(dimethylamino)propyl](meth)acrylamide, N-butoxymethyl(meth)acrylamide, diacetone(meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, vinylpyridine, vinylimidazole, acrylonitrile, methacrylonitrile, and the like. nzo«nn / ίζηζ / ε / γίΛΐ (6) Other vinyl compounds Examples include vinyl acetate, vinyl propionate, vinyl chloride, vinyl versatates, and similar compounds. Examples of vinyl versatates include the commercially available products VEOVA 9 and VEOVA10 (trade names, produced by Japan Epoxy Resin Co., Ltd.) and similar products. Like other polymerizable unsaturated monomers, those listed in (1) to (6) above can be used individually or in a combination of two or more. The term polymerizable unsaturated monomer, as used in this document, refers to a monomer having one or more (e.g., one to four) polymerizable unsaturated groups. A polymerizable unsaturated group is an unsaturated group that can undergo free-radical polymerization. Examples of polymerizable unsaturated groups include a vinyl group, a (meth)acrylate group, a (meth)acrylamide group, a vinyl ether group, an allyl group, a propenyl group, an isopropenyl group, a maleimide group, and the like. The term (meth)acrylate, as used in this document, means acrylate or methacrylate. The term (meth)acrylic acid means acrylic acid or methacrylic acid. The term (meth)acryloyl means acryloyl or methacryloyl. The term (meth)acrylamide means acrylamide or methacrylamide. From the point of view of curability and water resistance, the acrylic resin containing hydroxy (Bl-1) preferably has a hydroxy value of 70 to 200 mg KOH / g, more preferably 80 to 185 mg KOH / g and even more preferably 100 to 170 mg KOH / g. From the point of view of the final appearance and curability of the coating film, the acrylic resin containing hydroxy (Bl-1) preferably has a weight average molecular weight of 2000 to 50000, more preferably 3000 to 30000, and even more preferably 4000 to 10000. In this specification, the average molecular weight refers to a value calculated from a chromatogram measured by gel permeation chromatography based on the molecular weight of standard polystyrene. For gel permeation chromatography, HLC8120GPC (produced by Tosoh Corporation) was used. The measurement was carried out using four columns: TSKgel G-4000HXL, TSKgel G-3000HXL, TSKgel G-2500HXL, and TSKgel G-2000HXL (trade names, all produced by Tosoh Corporation) under the following conditions: mobile phase: tetrahydrofuran; measurement temperature: 40°C; flow rate: 1 cc / min; and detector: RI. The glass transition temperature of the acrylic resin containing hydroxy (Bl-1) is preferably within the range of -50 to 60°C, more preferably 10 to 50°C, and even more preferably 20 to 45°C, from the point of view of the hardness and finished appearance of the coating film. In this specification, the glass transition temperature (°C) of the acrylic resin was calculated using the following formulas. 1 / Tg (K) = (Wl / Tl) + (W2 / T2) +.....(1) Tg (°C) = Tg (K) - 273 (2) nzopnn / ίζηζ / ε / γίΛΐ In each formula, Wl, W2,... represent the mass fractions of the monomers used for copolymerization, and TI, T2,... represent the Tg (K) of the homopolymers of each of the monomers. TI, T2,... are the values ​​described in the Polymer Handbook (Second Edition, Brandrup and E.H. Immergut ed.), IP-139 to 179. When the Tg of a homopolymer of a monomer is unclear, the glass transition temperature (°C) refers to a static glass transition temperature. For example, a sample is taken in a measuring cup and subjected to vacuum suction to completely remove the solvent, followed by measuring the changes in the amount of heat at a heating rate of 3°C / min over a temperature range of -20 to +200°C using a DSC-220U differential scanning calorimeter (produced by Seiko Instruments Inc.). The initial change point on the baseline at the low-temperature end is considered to be the static glass transition temperature. The acrylic resin containing hydroxy (Bl-1) preferably has an acid value of 0.5 to 15 mg KOH / g, and particularly preferably 1 to 10 mg KOH / g, from the point of view, for example, of the shelf life of the paint composition and the final appearance. The method for copolymerizing the monomer mixture to obtain the hydroxy(Bl-1)-containing acrylic resin is not particularly limited, and known copolymerization methods can be used. Among these, a solution polymerization method is preferred, in which polymerization is carried out in an organic solvent in the presence of a polymerization initiator. Examples of organic solvents used in the solution polymerization method include toluene, xylene, Swasol 1000 (trade name, produced by Cosmo Oil Co., Ltd., a high-boiling-point oil-based solvent) and similar aromatic solvents; ethyl acetate, butyl acetate, propyl propionate, butyl propionate, l-methoxy-2-propyl acetate, 2-ethoxyethyl propionate, 3-methoxybutyl acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate and similar ester-based solvents; methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone and similar ketone-based solvents; isopropanol, n-butanol, isobutanol, 2-ethylhexanol and similar alcohol-based solvents; and the like. These organic solvents can be used individually or in combination with one or more of them. From the standpoint of acrylic resin solubility, ester-based and ketone-based solvents are preferable. An aromatic solvent can also be used appropriately in combination. Examples of polymerization initiators used to copolymerize the hydroxy (B1-1)-containing acrylic resin include known radical polymerization initiators such as 2,2'-azobisisobutyronitrile, benzoyl peroxide, di-t-butyl peroxide, di-t-amyl peroxide, t-butyl peroctoate, 2,2'-azobis(2-methylbutyronitrile), and 2,2'-azobis(2,4-dimethylvaleronitrile). Acrylic resins containing hydroxyl (Bl-1) can be used alone or in a combination of two or more. Secondary acrylic resin containing hydroxy (Bl-la) From the point of view of the final appearance of the resulting coating film, a secondary acrylic resin containing hydroxyl (Bl-la) can also be used appropriately as one of the modalities of the acrylic resin containing hydroxyl (Bl-1). The secondary acrylic resin containing hydroxyl (Bl-la) can be produced, for example, using a polymerizable unsaturated monomer containing secondary hydroxyl such as a type of polymerizable unsaturated monomer containing hydroxyl described above in the method for producing the acrylic resin containing hydroxyl (Bl-1). Examples of polymerizable unsaturated monomers containing a secondary hydroxyl group include polymerizable unsaturated monomers having a secondary hydroxyl group whose alkyl group in the ester radical has 2 to 8, preferably 3 to 6, and most preferably 3 or 4 carbon atoms, such as 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 3-hydroxybutyl (meth)acrylate; adducts of (meth)acrylic acid with an epoxy-containing compound (e.g., Cardura E10P, trade name, produced by Momentive Specialty Chemicals Inc., glycidyl ester of neodecanoic acid); and the like. These can be used alone or in combination. From the standpoint of the finished appearance of the resulting coating film, 2-hydroxypropyl (meth)acrylate is preferably used. When the above-described secondary hydroxy-containing polymerizable unsaturated monomer is used to produce the secondary hydroxy-containing acrylic resin (Bl-la), it is preferred that the amount of the secondary hydroxy-containing polymerizable unsaturated monomer be within the range of 15 to 45% by mass, and preferably 20 to 40% by mass, based on the total amount of copolymerizable monomeric components that constitute the secondary hydroxy-containing acrylic resin (Bl-la), from the point of view of the final appearance of the resulting coating film. In acrylic resin containing secondary hydroxyl (Bl-la), the content of the polymerizable unsaturated monomer containing secondary hydroxyl in the total amount of polymerizable unsaturated monomer containing hydroxyl is within the range of preferably 50 to 100% by mass, more preferably 55 to 100% by mass, and even more preferably 60 to 100% by mass, from the point of view of water resistance and the final appearance of the resulting coating film. Acrylic resin containing hydroxy and alkoxysilyl (Bl-lb) As another form of the acrylic resin containing hydroxy (Bl-1), an acrylic resin containing hydroxy and alkoxysilyl (Bl-lb) can preferably be used from the point of view of the scratch resistance of the resulting coating film. Hydroxy-alkoxysilyl (Bl-lb) acrylic resin is a resin that has at least one hydroxy group and at least one alkoxysilyl group per molecule. The use of acrylic resin containing hydroxy and alkoxysilyl (Bl-lb) forms a crosslink due to a condensation reaction between alkoxysilyl groups and a reaction between an alkoxysilyl group and a hydroxyl group, thus increasing the curability of the coating film. Examples of the alkoxy radical of the alkoxysilyl group present in acrylic resin containing hydroxy and alkoxysilyl (B1-B1) include an alkoxy radical having approximately 1 to 6 carbon atoms, preferably approximately 1 to 3 carbon atoms, such as methoxy, ethoxy, and propoxy. The alkoxy radical is most preferably methoxy and ethoxy, and particularly methoxy from the standpoint of the scratch resistance of the resulting coating film. The alkoxysilyl group includes a trialkoxysilyl group, a dialkoxysilyl group, and a monoalkoxysilyl group. The alkoxysilyl group is preferably a trialkoxysilyl group from the standpoint of the scratch resistance of the resulting coating film. When the alkoxysilyl group is a dialkoxysilyl group or a monoalkoxysilyl group, the groups other than the alkoxy that are attached to the silicon atom include alkyl having approximately 1 to 6 carbon atoms, preferably approximately 1 to 3 carbon atoms (e.g., methyl, ethyl, and propyl). The acrylic resin containing hydroxy and alkoxysilyl (Bl-lb) can be obtained, for example, by using an alkoxysilyl-containing polymerizable unsaturated monomer as a type of polymerizable unsaturated monomer and other polymerizable unsaturated monomers in the method for producing the acrylic resin containing hydroxy (Bl-1). An alkoxysilyl-containing polymerizable unsaturated monomer is a compound that has at least one alkoxysilyl group and at least one polymerizable unsaturated bond per molecule. Examples of alkoxysilyl-containing polymerizable unsaturated monomers include vinyltrimethoxysilane, vinyltriethoxysilane, acryloxyethyltrimethoxysilane, methacryloxyethyltrimethoxysilane, meta-yloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, acryloxypropyltriethoxysilane, methacryloxypropyltriethoxysilane, and vinyltris(3-methoxyethoxy)silane. The polymerizable unsaturated monomer containing alkoxysilyl is preferably vinyltrimethoxysilane, γ-acryloxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane, and more preferably γ-methacryloxypropyltrimethoxysilane from the point of view of the scratch resistance of the resulting coating film. The polymerizable unsaturated monomer containing alkoxysilyl for use may be a commercially available product. Examples include KBM-1003, KBE-1003, KBM-502, KBM-503, KBE-502, KBE-503, KBM-5103, and KBM-5803 (all produced by Shin-Etsu Chemical Co., Ltd.); Y-9936 and A-174 (produced by Momentive Performance Materials Inc.); and OFS-6030 and Z-6033 (produced by Dow Toray Co., Ltd.). These polymerizable unsaturated monomers containing alkoxysilyl can be used alone or in combination with two or more. Specifically, the acrylic resin containing hydroxyl and alkoxysilyl (Bl-lb) can be obtained, for example, by copolymerizing the polymerizable unsaturated monomer containing hydroxyl, the polymerizable unsaturated monomer containing alkoxysilyl, and other polymerizable unsaturated monomers (polymerizable unsaturated monomers other than the polymerizable unsaturated monomer containing hydroxyl and the polymerizable unsaturated monomer containing alkoxysilyl). The other polymerizable unsaturated monomers that can be used in the copolymerization are, for example, other polymerizable unsaturated monomers (1) to (6) for use in obtaining the acrylic resin containing hydroxyl (Bl-1). The polymerizable unsaturated monomers can be used alone or in combination with two or more. When producing the hydroxy-alkoxysilyl (Bl-lb) containing acrylic resin, the amount of polymerizable unsaturated monomer containing hydroxy for use is preferably within the range of 5 to 60% by mass, more preferably 15 to 50% by mass, and even more preferably 25 to 45% by mass, based on the total amount of copolymerizable monomeric components constituting the hydroxy-alkoxysilyl (Bl-lb) containing acrylic resin from the standpoint of scratch resistance, water resistance, curability, and final appearance of the resulting coating film. The hydroxyl value of the acrylic resin containing hydroxyl and alkoxysilyl (Bl-lb) is preferably within the range of 70 to 200 mg KOH / g, more preferably 80 to 190 mg KOH / g and even more preferably 100 to 180 mg KOH / g from the point of view of scratch resistance, water resistance, curability and finished appearance of the resulting coating film. Secondary acrylic resin containing hydroxy and alkoxysilyl (Bl-lc) As another form of acrylic resin containing hydroxyl (Bl-1), a secondary acrylic resin containing hydroxyl and alkoxysilyl (Bl-lc) can be used from the point of view of the finished appearance and scratch resistance of the resulting coating film. The secondary acrylic resin containing hydroxy and alkoxysilyl (Bl-lc) is included in the secondary acrylic resin containing hydroxy (Bl-la) and also in the acrylic resin containing hydroxy and alkoxysilyl (Bllb). The secondary acrylic resin containing hydroxy and alkoxysilyl (Bl-lc) can be produced, for example, using a polymerizable unsaturated monomer containing secondary hydroxy (e.g., a polymerizable unsaturated monomer containing secondary hydroxy usable in the production of the secondary acrylic resin containing hydroxy (Bl-la)) as a type of polymerizable unsaturated monomer containing hydroxy in the method for producing the acrylic resin containing hydroxy and alkoxysilyl (Bl-lb). When the above-described secondary hydroxy-containing polymerizable unsaturated monomer is used in the production of the secondary hydroxy- and alkoxysilyl-containing acrylic resin (Bl-lc), the amount of the secondary hydroxy-containing polymerizable unsaturated monomer for use is preferably within the range of 15 to 45% by mass, and more preferably 20 to 40% by mass based on the total amount of copolymerizable monomeric components constituting the secondary hydroxy- and alkoxysilyl-containing acrylic resin (Bl-lc) from the point of view of the final appearance of the resulting coating film. In the production of secondary acrylic resin containing hydroxy and alkoxysilyl (Bl-lc), the content of the polymerizable unsaturated monomer containing secondary hydroxy in the total amount of polymerizable unsaturated monomer containing hydroxy is preferably within the range of 50 to 100% by mass, more preferably 55 to 100% by mass, and even more preferably 60 to 100% by mass from the point of view of water resistance and the final appearance of the resulting coating film. Examples of film-forming resins usable as the binder component (B), other than those described above, in the paint composition of the present invention include hydroxy-free acrylic resin, hydroxy-containing or hydroxy-free polyester resin, hydroxy-containing or hydroxy-free polyether resin, and hydroxy-containing or hydroxy-free polyurethane resin. Of these, hydroxy-containing polyester resin and hydroxy-containing polyurethane resin are preferred as film-forming resins. Polyester resin containing hydroxyl groups can be produced using a commonly employed method, such as esterification between a polybasic acid and a polyhydric alcohol. A polybasic acid is a compound that has two or more carboxyl groups per molecule, such as italic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, fumaric acid, itaconic acid, trimellitic acid, pyromellitic acid, and their anhydrides.A polyhydric alcohol is a compound that has two or more hydroxyl groups per molecule, and examples include diols, such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-diethyl-1,3-propanediol, neopentyl glycol, 1,9-nonanediol, 1,4-acidohexanediol, neopentyl glycol ester of hydroxypivalic acid, 2-butyl-2-ethyl,3-propanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethylpentanediol, and hydrogenated bisphenol A; trihydric or higher polyol components, such as trimethylolpropane, trimethylolethane, glycerin, and pentaerythritol; and hydroxycarboxylic acids, such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolpentanoic acid, 2,2-dimethylolhexanoic acid and 2,2-dimethyloloctanoic acid. An α-olefin epoxide, such as propylene oxide and butylene oxide, or a monoepoxy compound, such as Cardura E10P (trade name, produced by Momentive Specialty Chemicals, a glycidyl ester of a highly branched synthetic saturated fatty additive), can be reacted with an additive to introduce these compounds into a polyester resin. The introduction of carboxyl groups into a polyester resin can be accomplished, for example, by adding an acid anhydride to a hydroxy-containing polyester and semi-esterifying the hydroxy-containing polyester. The hydroxyl value of the hydroxyl-containing polyester resin is preferably within the range of 80 to 250 mg KOH / g, more preferably 100 to 200 mg KOH / g. The weight average molecular weight of the hydroxyl-containing polyester resin is preferably within the range of 500 to 3500, and more preferably 500 to 2500. Hydroxy-containing polyurethane resin is, for example, a hydroxy-containing polyurethane resin obtained by reacting a polyol with a polyisocyanate. nzopnn / ίζηζ / ε / γίΛΐ Examples of low molecular weight polyols include dihydric alcohols, such as ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, and hexamethylene glycol; and trihydric alcohols, such as trimethylolpropane, glycerin, and pentaerythritol. Examples of high molecular weight polyols include polyether polyols, polyester polyols, acrylic polyols, and epoxy polyols. Examples of polyether polyols include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Examples of polyester polyols include the dihydric alcohols described above, polycondensation products of an alcohol, such as dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, or neopentyl glycol, with a dibasic acid, such as adipic acid, azelaic acid, or sebacic acid. lactone-based ring-opening polymeric polyols, such as polycaprolactone; and polycarbonate diol.For example, polyols containing carboxyls such as 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid can also be used. Examples of polyisocyanates reacting with a polyol include aliphatic polyisocyanates, such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimeric acid diisocyanate, and lysine diisocyanate; biuret-type adducts of these polyisocyanates and isocyanurate ring adducts of these polyisocyanates; alicyclic diisocyanates, such as isophorone diisocyanate, 4,4'-methylene bis(cyclohexylisocyanate), methylcyclohexane-2,4-(or -2,6-)diisocyanate, 1,3-(or 1,4-)di(isocyanatomethyl)cyclohexane, 1,4-cyclohexane diisocyanate, 1,3-cyclopentane diisocyanate, and 1,2-cyclohexane diisocyanate; biuret-type adducts of these polyisocyanates and isocyanurate ring adducts of these polyisocyanates;aromatic diisocyanate compounds, such as xylylene diisocyanate, meta-xylylene diisocyanate, tetramethylxylylene diisocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 4,4-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, (m- or p-)phenylene diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimet-M,4'-biphenylene diisocyanate, bis(4-isodanatophenyl) sulfone and isopropylidene bis(4-phenylisocyanate); biuret-type adducts of these polyisocyanates and isocyanurate ring adducts of these polyisocyanates; polyisocyanates having three or more isocyanate groups per molecule, such as triphenylmethane-4,4',4-triisocyanate, 1,3,5-triisocyanatebenzene, 2,4,6-triisocyanate toluene and 4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate; and biuret-type adducts of these polyisocyanates, and isocyanurate ring adducts of these polyisocyanates. The hydroxyl value of the polyurethane resin containing hydroxyl is preferably within the range of 80 to 250 mg KOH / g, more preferably 100 to 200 mg KOH / g. The weight average molecular weight of the polyurethane resin containing hydroxyl is preferably within the range of 500 to 10,000, and more preferably 1,000 to 5,000. When hydroxy-containing acrylic resin (Bl-1) and a resin other than hydroxy-containing acrylic resin (Bl-1) (more specifically, polyester resin, polyurethane resin, polyether resin, etc.) are used in combination as the binder component (B), the content of the resin other than hydroxy-containing acrylic resin (Bl-1) is preferably within the range of 50 parts by mass or less, and more preferably from 1 to 20 parts by mass, per 100 parts by mass of the solids content of the hydroxy-containing acrylic resin (Bl-1). nzopnn / ίζηζ / Β / γίΛΐ Crosslinking agent (B2) In the paint composition of the present invention, the binder component (B) may contain a crosslinking agent (B2). The crosslinking agent (B2) is a compound that can react with a crosslinkable functional group in the binder component (B) and form a crosslinking structure through the reaction. Preferably, the crosslinkable functional group in the binder component (B) is a hydroxyl group, and the crosslinking agent (B2) is a compound that is reactive with a hydroxyl group. Specifically, for example, the crosslinking agent (B2) is preferably a polyisocyanate compound, a blocked polyisocyanate compound, or an amino resin. In particular, from the standpoint of finished appearance, scratch resistance, and the like, the crosslinking agent (B2) preferably contains a polyisocyanate compound. A polyisocyanate compound is a compound that has at least two isocyanate groups per molecule. Examples include aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, aromatic-aliphetic polyisocyanate compounds, aromatic polyisocyanate compounds, derivatives of these polyisocyanate compounds, and the like. Examples of aliphatic polyisocyanate compounds include aliphatic diisocyanate compounds, such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, dimeric acid diisocyanate, and methyl 2,6-diisocyanatehexanoate (common name: lysine diisocyanate); aliphatic triisocyanate compounds, such as 2,6-ethyl 2-isocyanatohexanoate, 1,6-diisocyanato-3-methylhexane, 1,4,8-triisocyanatooctane, 1,6,11-triisocyanatoundecane, 1,8-diisocyanato-1-methyl, 1,3,6-triisocyanatohexane and 2,5,7-trimethyl1,8-diisocyanato-5-methyloctane; and the like. Examples of alicyclic polyisocyanate compounds include alicyclic diisocyanate compounds such as 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatemethyl-3,5,5-trimethylcyclohexyl isocyanate (common name: isophorone diisocyanate), 4-methyl-1,3-cyclohexylene diisocyanate (common name: hydrogenated TDI), 2-methyl-1,3-cyclohexylene diisocyanate, 1,3- or 1,4-bis(isocyanatomethyl)cidohexane (common name: hydrogenated xylylene diisocyanate) or mixtures thereof, and methylenebis(4,1-d-chlorohexanedyl)diisocyanate (common name: hydrogenated MDI) and norbornane diisocyanate; alicyclic triisocyanate compounds, such as 1,3,5-triisocyanatocyclohexane, 1,3,5-trimethylisocyanatocyclohexane, 2-(3-socyanatopropyl)-2,5-d¡(socyanatomethyl)-bidclo(2.2.1)heptane, 2-(3-¡sodanatoprop¡l)-2,6-d¡(isodanatomethyl)bicyclo(2.2. l)heptane, 3-(3-¡sodanatoprop¡l)-2,5-d¡(¡sodanatomethyl)-bicyclo(2.2.l)heptane, 5-(2-ocyanatoethyl)-2-socyanatomethyl-3-(3-sodanatopropyl)-bidclo(2.2.1)heptane, and 6-(2-socyanatoethyl)-2-socyanatomethyl·2-(3-socyanatopropyl)-bicyclo(2.2. l)heptane; and the like. nzo«nn / ίζηζ / ε / γίΛΐ Examples of aromatic-aliphatic polyisocyanate compounds include aromatic-aliphatic diisocyanate compounds, such as methylenebis(4,l-phenylene)diisocyanate (common name: MDI), 1,3- or 1,4-xylylene diisocyanate or mixtures thereof, and 1,3-ol,4-bis(l-isocyanate-l-methylethyl)benzene (common name: tetramethylxylylene diisocyanate) or mixtures thereof; aromatic-aliphatic triisocyanate compounds, such as 1,3,5-methylbenzene triisocyanate; and the like. Examples of aromatic polyisocyanate compounds include aromatic diisocyanate compounds, such as m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 2,4-tolylene diisocyanate (common name: 2,4-TDI) or 2,6-tolylene diisocyanate (common name: 2,6-TDI) or mixtures thereof, 4,4'-toluidine diisocyanate and 4,4'-diphenyl ether diisocyanate; aromatic triisocyanate compounds, such as triphenylmethane-4,4',4-triisocyanate, 1,3,5-benzene triisocyanate and 2,4,6-toluene triisocyanate; aromatic tetraisocyanate compounds, such as 4,4'-diphenylmethane-2,2',5,5'-tetraisocyanate; and the like. Examples of derivatives of polyisocyanate compounds include dimers, trimers, biurets, allophenates, urethdiones, urethymine, isocyanurates, oxadiazinetriones, polymethylene polyphenyl polyisocyanates (crude MDI, polymeric MDI), crude TDI and the like, of the polyisocyanate compounds mentioned above. The polyisocyanate compounds and derivatives thereof mentioned above can be used individually or in a combination of two or more. From the standpoint of weather resistance, etc., of the resulting coating film, the polyisocyanate compound to be used is preferably at least a member selected from the group consisting of an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound, and a derivative thereof. From the standpoint of increasing the solids content of the resulting paint composition, and improving the finished appearance and scratch resistance of the coating film, the polyisocyanate compound to be used is more preferably an aliphatic polyisocyanate compound and / or a derivative thereof. The aliphatic polyisocyanate compound and / or a derivative thereof for use is preferably an aliphatic diisocyanate compound and / or an isocyanurate thereof, and more preferably hexamethylene diisocyanate and / or an isocyanurate thereof, from the point of view of an increase in the solids content of the resulting paint composition, and the final appearance and scratch resistance of the resulting coating film. When the paint composition of the present invention contains a polyisocyanate compound described above as the crosslinking agent (B2), the proportion of the polyisocyanate compound is preferably within the range of 5 to 60 parts by mass, more preferably 15 to 50 parts by mass, and even more preferably 25 to 45 parts by mass, per 100 parts by mass of the total solids content of the hydroxy-containing resin (B1) and the crosslinking agent (B2), from the point of view of the finished appearance and scratch resistance of the resulting coating film. nzo«nn / ίζηζ / ε / γίΛΐ The blocked polyisocyanate compound usable as the crosslinking agent (B2) is a compound obtained by blocking isocyanate groups of a polyisocyanate compound described above with a blocking agent. Examples of blocking agents include phenolic compounds, such as phenol, cresol, xylenol, nitrophenol, ethylphenol, hydroxyphenyl, butylphenol, isopropionylphenol, nonylphenol, octylphenol, and methyl hydroxybenzoate; lactam compounds, such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, and β-propiolactam; aliphatic alcohol compounds, such as methanol, ethanol, propyl alcohol, butyl alcohol, amyl alcohol, and lauryl alcohol; ether compounds, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and methoxymethanol;Alcoholic compounds, such as benzyl alcohol, glycolic acid, methyl glycolate, ethyl glycolate, butyl glycolate, lactic acid, methyl lactate, ethyl lactate, butyl lactate, methylol urea, methylol melamine, diacetone alcohol, 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate; oxime compounds, such as formamide oxime, acetamide oxime, acetoxime, methyl ethyl ketoxime, diacetyl monoxime, benzophenone oxime and cyclohexane oxime; active methylene compounds, such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, methyl acetoacetate and acetylacetone; mercaptan compounds, such as butyl mercaptan, t-butyl mercaptan, hexyl mercaptan, t-dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol, methyl thiophenol and ethyl thiophenol; acid amide compounds, such as acetanilide, acetanisidide, aoetotoluide, acrylamide, methacrylamide, acetic acid amide, stearic acid amide and benzamide;Imidine compounds, such as succinimide, phthalimide, and maleimide; amine compounds, such as diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine, dibutylamine, and butylphenylamine; imidazole compounds, such as imidazole and 2-ethylimidazole; urea compounds, such as urea, thiourea, ethylenurea, ethylthiourea, and diphenylurea; carbamate compounds, such as phenyl N-phenylcarbamate; imine compounds, such as ethylenimine and propylenimine; sulfite compounds, such as sodium bisulfite and potassium bisulfite; azole compounds; and the like. Examples of azole compounds include pyrazole or pyrazole derivatives, such as pyrazole, 3,5-dimethylpyrazole, 3-methylpyrazole, 4-benzyl-3,5-dimethylpyrazole, 4-nitro-3,5-dimethylpyrazole, 4-bromo-3,5-dimethylpyrazole, and 3-methyl-5-phenylpyrazole; imidazole or imidazole derivatives, such as imidazole, benzimidazole, 2-methylimidazole, 2-ethylimidazole, and 2-phenylimidazole;imidazoline derivatives, such as 2-methylimidazoline and 2-phenylimidazoline; and the like. Particularly preferred blocking agents are, for example, oxime-based blocking agents, active methylene-based blocking agents, and pyrazole or pyrazole derivatives. When blocking is performed (a blocking agent is reacted), a solvent may be added, if necessary. The solvent used in the blocking reaction is preferably one that is non-reactive with an isocyanate group. Examples of such solvents include ketones, such as acetone and methyl ethyl ketone; esters, such as ethyl acetate; N-methyl-2-pyrrolidone (NMP); and similar solvents. When the paint composition of the present invention contains a blocked polyisocyanate compound described above as the crosslinking agent (B2), the proportion of the blocked polyisocyanate compound is preferably within the range of 5 to 60 parts by mass, more preferably 15 to 50 parts by mass, and even more preferably 25 to 45 parts by mass, per 100 parts by mass of the total solids content of the binder component, from the point of view of the finished appearance and scratch resistance of the resulting coating film. When the paint composition of the present invention contains a polyisocyanate compound and / or a blocked polyisocyanate compound described above as a crosslinking agent (B2), the ratio is preferably such that the equivalent ratio (NCO / OH) of the total isocyanate groups (including blocked isocyanate groups) in the polyisocyanate compound and the blocked polyisocyanate compound to the hydroxy groups of the hydroxy-containing resin (B1) is generally within the range of 0.5 to 2, and preferably 0.8 to 1.5, from the point of view of water resistance and finished appearance of the resulting coating film. Amino resins that can be used as crosslinking agents (B2) include pardal or fully methylated amino resins obtained by reacting an amino component with an aldehyde component. Examples of amino components include melamine, urea, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine, dicyandiamide, and the like. Examples of aldehyde components include phthalmaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, and the like. Also usable are those obtained by etherifying some or all of the methylol groups of the above aminomethylated resins with a suitable alcohol. Examples of alcohols usable for etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-ethylbutanol, 2-ethylhexanol, and the like. The preferred amino resins are melamine resins. Examples of usable melamine resins include alkyl etherified melamine resins obtained by etherifying some or all of the methylol groups of partially or fully methylated melamine resins with the alcohol. Preferred examples of alkyl etherified melamine resins include methyl etherified melamine resins obtained by etherifying some or all of the methylol groups of partially or fully methylolated melamine resins with methyl alcohol; butyl etherified melamine resins obtained by etherifying some or all of the methylol groups of brown or fully methylolated melamine resins with butyl alcohol; mixed methyl-butyl etherified melamine resins obtained by etherifying some or all of the methylol groups of brown or fully methylolated melamine resins with methyl alcohol and butyl alcohol; and the like. Melamine resin has an average molecular weight preferably of 400 to 6000, more preferably of 500 to 5000 and even more preferably of 800 to 4000. A commercially available product such as melamine resin can be used. Examples of commercially available products include Cymel 202, Cymel 203, Cymel 238, Cymel 251, Cymel 303, Cymel 323, Cymel 324, Cymel 325, Cymel 327, Cymel 350, Cymel 385, Cymel 1156, Cymel 1158, Cymel 1116, Cymel nzopnn / ίζηζ / ε / γίΛΐ 1130, (all produced by Allnex Japan Inc.), U-VAN 120, U-VAN 20HS, U-VAN 20SE60, U-VAN 2021, U-VAN 2028, U-VAN 28-60 (all produced by Mitsui Chemicals, Inc.) and similar. The melamine resins described above can be used alone or in a combination of two or more. When the paint composition of the present invention contains an amino resin described above as the crosslinking agent (B2), its proportion is preferably within the range of 0.5 to 40 parts by mass, more preferably 1 to 15 parts by mass, even more preferably 1.5 to 10 parts by mass, and even more preferably 1.5 to 5 parts by mass, per 100 parts by mass of the total solids content of the binder component, from the point of view of water resistance and the final appearance of the resulting coating film. Crosslinking agents (B2) can be used individually or in a combination of two or more. From the point of view of sagging resistance during coating and resistance to water reddening and the final appearance of the resulting coating film, the content of the rheology control agent (A) in the paint composition of the present invention is preferably within the range of 0.1 to 2 parts by mass, more preferably 0.2 to 1.5 parts by mass, and even more preferably 0.3 to 1 part by mass, per 100 parts by mass of the total solids content of the binder component (B). The paint composition of the present invention has excellent resistance to sagging during coating and is capable of forming a coating film with excellent finished appearance and resistance to water reddening. The reason for this is presumed to be the following: A rheology control agent containing a reaction product of the polyisocyanate compound (a1), where the primary monoamine has a number-average molecular weight of 300 or less (a2), and the polyetheramine has two or more amino groups and a number-average molecular weight of 1000 or more and less than 6000 (a3), serves as a rheology control agent with a fine crystalline structure. It forms a dense network in the paint composition to exert sag control capabilities, thereby improving sag resistance during coating and the final appearance of the resulting coating film. Furthermore, the fine crystalline structure enhances solubility during coating film formation; therefore, a coating film with excellent resistance to water reddening is formed. The paint composition of the present invention may further contain, if necessary, color pigments, effect pigments, dyes, or the like. The paint composition of the present invention may also contain extender pigments, ultraviolet absorbers, light stabilizers, catalysts, antifoaming agents, rheology control agents other than rheology control agent (A), anticorrosives, surface adjustment agents, organic solvents, and the like. Examples of color pigments include titanium oxide, zinc white, carbon black, cadmium red, molybdenum red, chromium yellow, chromium oxide, Prussian blue, cobalt blue, azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, threonine pigments, perylene pigments, and the like. Examples of effect pigments include aluminum powder, mica powder, titanium oxide-coated mica powder, and the like. Examples of extender pigments include talc, clay, kaolin, barite, barium sulfate, barium carbonate, broth carbonate, alumina white, and the like. The above pigments can be used individually or in a combination of two or more. When the paint composition of the present invention is used as a transparent paint and contains a pigment, the pigment is preferably used in an amount such that the transparency of the resulting coating film is not impaired. For example, the amount of pigment is generally within the range of 0.1 to 20% by mass, preferably 0.3 to 10% by mass, and more preferably 0.5 to 5% by mass, based on the total solids content in the paint composition. When the paint composition of the present invention is used as colored paint and contains a pigment, the amount of pigment is generally within the range of 1 to 200% by mass, preferably 2 to 100% by mass, and more preferably 5 to 50% by mass, based on the total solids content in the paint composition. Solids content, as used in this document, refers to the non-volatile components of resin, curing agent, pigment, and the like that remain in the paint composition after drying the paint composition at 110°C for 1 hour. For example, the total solids content of the paint composition can be calculated as follows. The paint composition is measured in a heat-resistant container, such as an aluminum foil cup, spread on the bottom of the container, and then dried at 110°C for 1 hour. After drying, the mass of the components remaining in the paint composition is measured to determine the ratio of the mass of the components remaining after drying to the total mass of the paint composition before drying. Examples of ultraviolet absorbers include well-known ultraviolet absorbers such as benzotriazole absorbers, triazine absorbers, salicylic acid derivative absorbers, benzophenone absorbers, and similar ultraviolet absorbers. These ultraviolet absorbers can be used individually or in combination with one or more of them. When the paint composition of the present invention contains an ultraviolet absorber, the amount of ultraviolet absorber is generally within the range of 0.1 to 10% by mass, preferably 0.2 to 5% by mass, and more preferably 0.3 to 2% by mass, based on the total solids content in the paint composition. Examples of light stabilizers include well-known light stabilizers, such as hindered amine light stabilizers. The hindered amine light stabilizer for use is preferably a hindered amine light stabilizer that has low basicity from a lifetime standpoint. Examples of such hindered amine light stabilizers include adiated hindered amines, amino ether-based hindered amines, and the like. Specific examples include HOSTAVIN 3058 (trade name, produced by Clariant), TINUVIN 123 (trade name, produced by BASF), and the like. When the paint composition of the present invention contains a light stabilizer, the amount of light stabilizer is generally within the range of 0.1 to 10% by mass, preferably 0.2 to 5% by mass, and more preferably 0.3 to 2% by mass, based on the total solids content in the paint composition. Examples of catalysts include known catalysts. For example, when the paint composition of the present invention contains the polyisocyanate compound and / or the blocked polyisocyanate compound mentioned above as a crosslinking agent (B2), the paint composition of the present invention may contain a urethane reaction catalyst. Specific examples of urethane reaction catalysts include organometallic compounds such as tin octylate, dibutyltin diacetate, dibutyltin di(2-ethylhexanoate), dibutyltin dilaurate, dioctyltin diacetate, dioctyltin di(2-ethylhexanoate), dibutyltin oxide, dibutyltin sulfide, dioctyltin oxide, dibutyltin fatty acid salts, lead 2-ethylhexanoate, zinc octylate, zinc naphthenate, zinc fatty acid salts, bismuth octanoate, bismuth 2-ethylhexanoate, bismuth oleate, bismuth neodecanoate, bismuth versatate, bismuth naphthenate, cobalt naphthenate, copper octylate, and tetra(2-ethylhexyl)titanate; tertiary amine; and the like. These can be used alone or in a combination of two or more. When the paint composition of the present invention contains a urethane reaction catalyst described above, the amount of the urethane reaction catalyst is preferably within the range of 0.005 to 2% by mass, and more preferably from 0.01 to 1% by mass, based on the total solids content in the paint composition of the present invention. When the paint composition of the present invention contains a urethane reaction catalyst described above, the paint composition of the present invention may contain acetic acid, propionic acid, butyric acid, isopentanoic acid, hexanoic acid, 2-ethylbutyric acid, naphthenic acid, octyl acid, nonanoic acid, decanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, neodecanoic acid, versatic acid, isobutyric anhydride, itaconic anhydride, acetic anhydride, ditraconic anhydride, propionic anhydride, maleic anhydride, butyric anhydride, citric anhydride, trimellitic anhydride, pyromellitic anhydride, italic anhydride or similar organic acid; hydrochloric acid, phosphoric acid or similar inorganic acid; acetylacetone, an imidazole compound or a similar metal coordination compound;or similar, from the point of view of storage stability, curability, or similar.; When a melamine resin described above is used as the crosslinking agent nzo«nn / ίζηζ / ε / γίΛΐ (B2) in the paint composition of the present invention, the paint composition of the present invention may contain, as a curing catalyst, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, or similar sulfonic acid; monobutyl phosphate, dibutyl phosphate, mono(2-ethylhexyl) phosphate, di(2-ethylhexyl) phosphate, or similar alkyl phosphoric esters; a salt of said acid with an amine compound; or the like. When the paint composition of the present invention contains a curing catalyst for the melamine resin, it is preferred that the amount of curing catalyst for the melamine resin be within the range of 0.1 to 2% by mass, preferably 0.2 to 1.7% by mass, and more preferably 0.3 to 1.4% by mass, based on the total solids content in the paint composition of the present invention. The substrate to be coated with the paint composition of the present invention is not particularly limited. Examples of substrates include exterior panel parts of automobile bodies such as passenger cars, trucks, motorcycles, and buses; automotive parts; exterior panel parts of household appliances such as mobile phones and audio equipment; and the like. Exterior panel parts of automobile bodies and automotive parts are particularly preferred. The substrate material is not particularly limited. Examples include metallic materials such as iron, aluminum, brass, copper, tinplate, stainless steel, galvanized steel, zinc-alloyed steel (Zn-Al, Zn-Ni, Zn-Ee, or similar); plastic materials such as polyethylene resins, polypropylene resins, acrylonitrile butadiene styrene (ABS) resins, polyamide resins, acrylic resins, vinylidene chloride resins, polycarbonate resins, polyurethane resins, epoxy resins, and similar resins, and various types of FRP; inorganic materials such as glass, cement, and concrete; wood; textile materials (e.g., paper and fabric); and similar materials. Of these, metallic and plastic materials are preferred. The substrate may be a metallic material mentioned above, or a vehicle body, etc., formed from a metallic material mentioned above that has undergone a surface treatment, such as phosphoric acid salt treatment, aromate treatment, or compound oxide treatment. The substrate may also be a metallic material, vehicle body, or similar material mentioned above onto which a coating film of various electroplated paints has been formed. The substrate may also be a metallic material, vehicle body, or similar material mentioned above onto which a lower coating film of various electroplated paints has been formed, and an intermediate coating film has been further formed on top of the lower coating film.The substrate can also be a plastic material, such as a bumper, on which a primer coating film has been formed. The method of applying a paint containing the paint composition of the present invention (hereinafter sometimes referred to simply as the paint of the present invention) is not particularly limited. For example, air spray coating, airless spray coating, rotary atomizing coating, curtain coating, or other coating methods may be used to form a wet coating film. In these coating methods, an electrostatic charge may be applied, if necessary. Of these methods, air spray coating or rotary atomizing coating are particularly preferred. The paint of the present invention is generally applied preferably to a cured film thickness of 10 to 60 µm, and more preferably from 25 to 55 µm.In particular, the thickness of the cured film is preferably 35 to 55 pm, and particularly preferably 41 to 50 pm. When applying an air-spray coating, an airless spray coating, or a rotary atomizing coating, it is preferred that the paint of the present invention be suitably adjusted beforehand by adding a solvent, such as an organic solvent, so that it has a viscosity suitable for the coating, which is generally 15 to 60 seconds, and preferably 20 to 40 seconds, as measured with a Ford Cup No. 4 viscometer at 20°C. The wet coating film obtained by applying the paint of the present invention to a substance can be cured by heating. Heating can be carried out using known heating means. For example, a drying oven, such as a hot air oven, an electric oven, or an infrared induction heating oven, can be used. The heating temperature is not particularly limited and is, for example, within the range of 60 to 160°C, and preferably 80 to 140°C. The heating time is not particularly limited and is, for example, within the range of 10 to 60 minutes, and preferably 15 to 30 minutes. The paint of the present invention, which is a paint composition capable of forming a coating film that has both excellent resistance to water reddening and a finished appearance, can be suitable for use, in particular, as a clear topcoat. The paint of the present invention can be suitable for use as paint, particularly for automobiles. Method for forming a multi-layer coating film The method for forming a multi-layer coating film in which the paint of the present invention is applied as the top clear coat paint may be a method for forming a multi-layer coating film comprising sequentially forming on a substrate at least one colored base coat paint layer and at least one clear coat paint layer, wherein the paint composition of the present invention is applied as the clear coat paint to form the top layer. Specific examples of such a method include a method for forming a multilayer coating film by a 1-2-layer baking method, wherein colored basecoat paint is applied to a substrate onto which an electrodeposited coating film and / or an intermediate coating film has been applied, the resulting uncured coating film is preheated, as required, to, for example, 40 to 90°C for approximately 3 to 30 minutes to accelerate solvent vaporization in the colored basecoat paint, and the paint of the present invention is then applied as a clearcoat paint to the uncured colored basecoat film, followed by simultaneous curing of the colored basecoat film and the clearcoat film. The paint of the present invention can also be suitablely used as a clear topcoat paint for topcoating in a 2-3-layer baking method or a 1-3-layer baking method. The basecoat paint used in the manner described above may be a commonly known thermosetting basecoat paint. Specific examples include paints obtained by the appropriate combination of a crosslinking agent, such as an amino resin, a polyisocyanate compound, or a blocked polyisocyanate compound, with reactive functional groups from a base resin, such as an acrylic resin, a polyester resin, an alkyd resin, or a urethane resin. As with basecoat paint, other types of paints can also be used, such as water-based paint, organic solvent-based paint, or powder coating. From the perspective of the finished appearance of the coating film and a reduction in environmental impact, water-based paint is preferable. When two or more transparent coating films are formed in the method for forming a multi-layer coating film, the paint of the present invention or known thermosetting transparent coating paint can be used as a clear coat paint to form a layer distinct from the top layer. EXAMPLES The present invention is described in more detail below with reference to production examples, examples, and comparative examples. However, the present invention is not limited to these. In each example, parts and percentages are expressed by mass unless otherwise specified, and film thickness is the thickness of a cured coating film. Production of acrylic resin containing hydroxy IB1-1-1) PRODUCTION EXAMPLE 1 Twenty-seven parts of Swasol 1000 (trade name, produced by Cosmo Gil Co., Ltd., an aromatic organic solvent) and five parts of propylene glycol monomethyl ether acetate were placed in a reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, a nitrogen inlet tube, and a dropping funnel. While nitrogen gas was blown into the reaction vessel, the mixture was stirred at 150°C. A mixture of monomers comprising 20 parts styrene, 32.5 parts 2-hydroxypropyl acrylate, 46.5 parts isobutyl methacrylate, 1.0 part acrylic acid and 1.5 parts ditertiary amyl peroxide (polymerization initiator) was added dropwise at a constant rate for a period of 4 hours.The resulting mixture was aged at 150°C for 1 hour, cooled, and further diluted with the addition of 34 parts of butyl acetate, yielding a hydroxyl-containing acrylic resin solution (Bl-1-1) (acrylic resin solution containing secondary hydroxyl) with a solids concentration of 60% by mass. The resulting hydroxyl-containing acrylic resin (Bl-1-1) had a hydroxyl value of 140 mg KOH / g, an acid value of 8.0 mg KOH / g, a weight-average molecular weight of 10,000, and a glass transition temperature of 39°C. Production of acrylic resin containing hydroxy (Bl-1-2) PRODUCTION EXAMPLE 2 Thirty parts of Swasol 1000 (trade name, produced by Cosmo Oil Co., Ltd., an aromatic organic solvent) and ten parts of n-butanol were placed in a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, and a dropping funnel. While nitrogen gas was blown into the reaction vessel, the mixture was stirred at 125°C. A monomer mixture comprising 30 parts of γ-methacryloxypropyltrimethoxysilane, 32.5 parts of 2-hydroxypropyl acrylate, 20 parts of styrene, 17.5 parts of isobutyl methacrylate, and 7.0 parts of 2,2'-azobis(2-methylbutyronitrile) (polymerization initiator) was added dropwise at a constant rate for a period of four hours. The resulting mixture was then aged at 125°C for 30 minutes and a solution containing 0.5 parts of 2,2'-azobis(2-methylbutyronitrile) and 5.0 parts of Swasol 1000 (trade name, produced by Cosmo Oil Co.)., Ltd., an aromatic organic solvent) was added dropwise at a constant rate for 1 hour. The resulting mixture was aged at 125°C for 1 hour, cooled, and further diluted with the addition of 8 parts of butyl acetate, yielding a hydroxy-containing acrylic resin solution (Bl1-2) (a secondary hydroxy- and alkoxysilyl-containing acrylic resin solution) with a solids concentration of 65% by mass. The resulting hydroxy-containing acrylic resin (Bl-1-2) had an alkoxysilyl group content of 1.21 mmol / g, a hydroxyl value of 140 mg KOH / g, a weight-average molecular weight of 7000, and a glass transition temperature of 18°C. nzo«nn / Lznz / B / YiAi Production of acrylic resin containing hydroxy (61-1-3) PRODUCTION EXAMPLE 3 Thirty parts of Swasol 1000 (trade name, produced by Cosmo Oil Co., Ltd., an aromatic organic solvent) and ten parts of n-butanol were placed in a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, and a dropping funnel. While nitrogen gas was blown into the reaction vessel, the mixture was stirred at 125°C. A monomer mixture comprising 30 parts of γ-methacryloxypropyltrimethoxysilane, 32.5 parts of 2-hydroxyethyl methacrylate, 20 parts of styrene, 17.5 parts of isobutyl methacrylate, and 7.0 parts of 2,2'-azobis(2-methylbutyrontrile) (polymerization initiator) was added to the same mixture dropwise at a constant rate for a period of four hours. The resulting mixture was then aged at 125°C for 30 minutes and a solution containing 0.5 parts of 2,2'-azobis(2-methylbutyronitrile) and 5.0 parts of Swasol 1000 (trade name, produced by Cosmo Oil Co.)., Ltd., an aromatic organic solvent) was added to the same dropwise at a constant rate for 1 hour. The resulting mixture was then aged at 125°C for 1 hour, cooled, and further diluted with the addition of 8 parts of butyl acetate, thus obtaining a hydroxy-containing acrylic resin solution (Bl-1-3) (primary hydroxy- and alkoxysilyl-containing acrylic resin solution) having a solids concentration of 65% by mass. The obtained hydroxy-containing acrylic resin (Bl-1-3) had an alkoxysilyl group content of 1.21 mmol / g, a hydroxyl value of 140 mg KOH / g, a weight-average molecular weight of 7000, and a glass transition temperature of 39°C. Production of rheology control agent EXAMPLE 1 158.3 parts (solids content: 95.0 parts) of the hydroxy(Bl-1-1) acrylic resin solution obtained in the production example, 15.2 parts of Swasol 1000 (trade name, produced by Cosmo Oil Co., Ltd., an aromatic organic solvent), and 10 parts of n-butanol were placed in a reaction vessel equipped with a stirrer and a dropping funnel. Then, an amine mixture comprising 2.44 parts of benzylamine and 0.6 parts of JEFFAMINE D-2000 (trade name, produced by Huntsman Corporation, a polyoxypropylene-containing diamine, number-average molecular weight: 2000) was added to the same with stirring at room temperature. Subsequently, a mixture of 1.96 parts of hexamethylene diisocyanate and 11.5 parts of Swasol 1000 (trade name, produced by Cosmo Oil Co., Ltd., an aromatic organic solvent) was added dropwise with stirring to obtain a dispersion of the rheology control agent (AM-1).The rheology control agent dispersion obtained (AM-1) had a solids content of 50%. In the rheology control agent dispersion obtained (AM-1), the total mass of components (al) to (a3) ​​was 5.0 parts by mass, the mass of the hydroxy-containing acrylic resin (Bl-1-1), which is a resin component, was 95.0 parts by mass, and the ratio of (the total mass of components (al) to (a3)) / (the mass of the resin component) was 5 / 95. EXAMPLES 2 to 9 V COMPARATIVE EXAMPLES 1 to 8 nzopnn / ίζηζ / ε / γίΛΐ Dispersions of rheology control agents (AM-2) to (AM-17) were obtained in the same manner as in Example 1, except that the formulations shown in Table 1 were used. The rheology control agent dispersions obtained (AM-2) to (AM-17) had a solids content of 50%. The quantities of the components shown in Table 1 are expressed as solids content by mass. TABLE 1 Example 1 2 3 4 5 Rheology Control Agent Dispersion Name AM-1 AM-2 AM-3 AM-4 AM-5 Resin Component Hydroxy-Containing Resin (Bl) Hydroxy-Containing Acrylic Resin (Bl-1) Hydroxy-Containing Acrylic Resin (Bl-11) 95 95 95 95 95 Rheology Control Agent (A) Amine Mixture Primary monoamine having a number-average molecular weight of 300 or less (a2) Benzylamine 2.44 2.19 2.44 2.19 Octylamine 2.35 Polyetheramine having two or more amino groups and a number-average molecular weight of 1000 or more and less than 6000 (a3) ​​Diamine containing polyoxyalkylene chains JEFFAMINE D-2000 0.6 1.0 Triamine containing polyoxyalkylene chains JEFFAMINE T-3000 (*1) 0.6 1.0 1.0 Polyisocyanate compound (al) Aliphatic polyisocyanate compound Hexamethylene diisocyanate 1.96 1.81 1.96 1.81 1.65 Proportion of each component based on the total mass of components (al) to (a3) ​​(% by mass) Polyisocyanate compound (al) 39.3 36.1 39.3 36.1 33.1 Primary monoamine having a number average molecular weight of 300 or less (a2) 48.7 43.9 48.7 43.9 46.9. Polyether amine having two or more amino groups and a number average molecular weight of 1000 or more and less than 6000 (a3) ​​12 20 12 20 20 Total mass of components (al) to (a3) ​​5.0 5.0 5.0 5.0 5.0 Mass of resin component 95.0 95.0 95.0 95.0 95.0 Ratio (total mass of components (al) to (a3)) / (mass of resin component) 5 / 95 5 / 95 5 / 95 5 / 95 5 / 95 nzopnn / Lznz / E / γΐΛΐ TABLE 1 (continued-I) Example 6 7 8 9 Rheology Control Agent Dispersion Name AM-6 AM-7 AM-8 AM-9 Resin Component Hydroxy-Containing Resin (Bl) Hydroxy-Containing Acrylic Resin (Bl-1) Hydroxy-Containing Acrylic Resin (Bl-11) 97.5 95 95 95 Rheology Control Agent (A) Amine Mixture Primary Monoamine Having a Number Average Molecular Weight of 300 or Less (a2) Benzylamine 1.1 1.95 2.19 2.21 Polyetheramine Having Two or More Amino Groups and a Number Average Molecular Weight of 1000 or More and Less than 6000 (a3) ​​Diamine Containing Polyoxyalkylene Chains JEFFAMINE D-2000 0.50 Triamine Containing Polyoxyalkylene Chains JEFFAMINE T-3000 (*1) 0.5 1.4 0.50 JEFFAMINE T-5000 (*2) 1.0 Polyisocyanate compound (al) Aliphatic polyisocyanate compound Hexamethylene diisocyanate 0.9 1.65 1.81 1.79 Proportion of each component based on the total mass of components (al) to (a3) ​​(% by mass) Polyisocyanate compound (al) 36.0 33.0 36.1 35.7 Primary monoamine having a number average molecular weight of 300 or less (a2) 44.0 39.0 43.9 44.3 Polyetheramine having two or more amino groups and a number average molecular weight of 1000 or more and less than 6000 (a3) ​​20 28 20 20 Total mass of components (al) to (a3) ​​2.5 5.0 5.0 5.0 Mass of resin component 97.5 95.0 95.0 95.0 Ratio (total mass of components (al) to (a3)) / (mass of resin component) 2.5 / 97.5 5 / 95 5 / 95 5 / 95. TABLE 1 (continued-2) Comparative Example 1 2 3 4 Name of the rheology control agent dispersion AM-10 AM-11 AM-12 AM-13 Resin component Hydroxy-containing resin (Bl) Hydroxy-containing acrylic resin (Bl-1) Hydroxy-containing acrylic resin (Bl-11) 95 95 95 95 Rheology control agent (A) Amine mixture Primary monoamine having a number-average molecular weight of 300 or less (a2) Benzylamine 2.68 2.56 2.68 2.44 Polyether amine having two or more amino groups and a number-average molecular weight of 1000 or more and less than 6000 (a3) ​​Diamine containing polyoxyalkylene chains JEFFAMINE D-2000 0.2 0.4 Triamine containing polyoxyalkylene chains JEFFAMINE T-3000 (*1) 0.2 Polyether amine other than (a3) ​​Monoamine containing polyoxyalkylene chains JEFFAMINE M-1000 (*3) 0.6 Polyisocyanate compound (al) Aliphatic polyisocyanate compound Hexamethylene diisocyanate 2.12 2.04 2.12 1.96 Proportion of each component based on the total mass of components (al) to (a3) ​​(% by mass) Polyisocyanate compound (al) 42.4 40.8 42.4 44.5 Primary monoamine having a number average molecular weight of 300 or less (a2) 53.6 51.2 53.6 55.5 Polyetheramine having two or more amino groups and a number average molecular weight of 1000 or more and less than 6000 (a3) ​​4 8 4 0 Total mass of components (al) to (a3) ​​and polyetheramine other than (a3) ​​5.0 5.0 5.0 5.0 Mass of resin component 95.0 95.0 95.0 95.0 Ratio (total mass of components (al) to (a3) ​​and polyetheramine other than (a3)) / (mass of resin component) 5 / 95 5 / 95 5 / 95 5 / 95. nzopnn / ίζηζ / ε / γίΛΐ TABLE 1 (continued-3) Comparative Example 5 6 7 8 Rheology Control Agent Dispersion Name AM-14 AM-15 AM-16 AM-17 Resin Component Hydroxy-Containing Resin (Bl) Hydroxy-Containing Acrylic Resin (Bl-1) Hydroxy-Containing Acrylic Resin (Bl-11) 95 95 90 90 Rheology Control Agent (A) Amine Mixture Primary Monoamine Having a Number Average Molecular Weight of 300 or Less (a2) Benzylamine 2.25 2.32 4.65 5.28 Polyetheramine Having Two or More Amino Groups and a Number Average Molecular Weight of 1000 or More and Less than 6000 (a3) ​​Diamine Containing Polyoxyalkylene Chains JEFFAMINE D-2000 Triamine Containing Polyoxyalkylene Chains JEFFAMINE T-3000 (*1) Polyetheramine Other Than (a3) Triamine containing polyoxyalkylene chains JEFFAMINE T-403 (*4) 0.6 Diamine containing polyoxyalkylene chains JEFFAMINE D-400 (*5) 0.6 1.2 0.4 Polyisocyanate compound (al) Aliphatic polyisocyanate compound Hexamethylene diisocyanate 2.15 2.08 4.15 4.32 Proportion of each component based on the total mass of components (al) to (a3) ​​(% by mass) Polyisocyanate compound (al) 48.9 47.3 47.2 45.0 Primary monoamine having a number average molecular weight of 300 or less (a2) 51.1 52.7 52.8 55.0 Polyetheramine having two or more amino groups and a number average molecular weight of 1000 or more and less than 6000 (a3) ​​0 0 0 0 Total mass of components (al) to (a3) ​​and polyetheramine other than (a3) ​​5.0 5.0 10.0 10.0. nzopnn / ίζηζ / Β / γίΛΐ Mass of resin component 95.0 95.0 90.0 90.0 Ratio (total mass of components (al) to (a3) ​​and polyether amine other than (a3)) / (mass of resin component) 5 / 95 5 / 95 10 / 90 10 / 90 The asterisks (*) in Table 1 mean the following. * 1: JEFFAMINE T-3000: Trade name, produced by Huntsman Corporation, triamine containing polyoxyalkylene, number average molecular weight of 3000 * 2: JEFFAMINE T-5000: Trade name, produced by Huntsman Corporation, triamine containing polyoxyalkylene, number average molecular weight of 5000 * 3: JEFFAMINE M-1000: Trade name, produced by Huntsman Corporation, monoamine containing polyoxyalkylene, number average molecular weight of 1000 * 4: JEFFAMINE T-403: Trade name, produced by Huntsman Corporation, triamine containing polyoxyalkylene, number average molecular weight of 440 * 5: JEFFAMINE D-400: Trade name, produced by Huntsman Corporation, diamine containing polyoxyalkylene, number average molecular weight of 400 Production of the paint composition: Part 1 EXAMPLE 10 69.2 parts (solids content: 41.5 parts) of the hydroxy-containing acrylic resin solution (Bl-1-1) obtained in production example 1, 6.7 parts (solids content: 4 parts) of U-VAN 20SE60 (trade name, produced by Mitsui Chemicals, Inc., a melamine resin, solids content: 60%), 20 parts (solids content: 10 parts, in which the rheology control agent component (A) constitutes 0.5 parts, and the hydroxy-containing acrylic resin (Bl-1-1) constitutes 9.5 parts) of the rheology control agent dispersion solution (AM-1) obtained in example 1, 0.4 parts (solids content: 0.2 parts) of BYK-300 (trade name, produced by BYK-Chemie, a surface adjusting agent, active ingredient: 52%), and 0.3 parts (solids content: 0.1 parts) of NACURE 5523 (trade name, amine salt of dodecylbenzenesulfonic acid, active ingredient: 35%, produced by King Industries, Inc.) were mixed uniformly to obtain a main agent. The main agent and 35 parts of Sumidur N3300 (trade name, produced by Sumika Covestro Urethane Co., Ltd., a hexamethylene diisocyanurate isocyanurate, solids content: 100%), which is a curing agent (crosslinking agent (B2)), were mixed uniformly immediately before application, and butyl acetate was added to adjust the viscosity to 30 seconds, measured with a Ford Cup No. 4 at 20°C, thus obtaining paint composition No. 1. EXAMPLES 11 to 26 vs. COMPARATIVE EXAMPLES 9 to 19 Paint compositions No. 2 to 28 with a viscosity of 30 seconds measured with a No. 4 Ford Cup at 20°C were obtained in the same manner as in Example 10, except that the formulations shown in Table 2 below were used. The quantities of the components shown in Table 2 are expressed as solids content by mass. Test panel preparation: Part 1 Test panel preparation for examples 10 to 26 and comparative examples 9 to 19 Preparation of the test panel for the evaluation of the final appearance and resistance to water reddening. Elecron GT-10 (trade name, produced by Kansai Paint Co., Ltd., cationic electroplating paint) was applied by electroplating to a zinc phosphate-treated cold-rolled steel plate (10 cm x 15 cm) to a dry film thickness of 20 µm and cured by heating to 170°C for 30 minutes. Subsequently, WP-306T (trade name, produced by Kansai Paint Co., Ltd., melamine polyester resin-based aqueous intermediate paint) was electrostatically applied to the electroplating film using a rotary atomizing electrostatic coating machine to a cured film thickness of 30 µm and allowed to rest for 5 minutes, followed by preheating to 80°C for 3 minutes and then heating to 140°C for 30 minutes, thus preparing a test substrate. Subsequently, WBC-713T No. 202 (trade name, produced by Kansai Paint Co., Ltd.A water-based acrylic melamine resin-based basecoat paint (coat color: black) was electrostatically applied to the test substrate held in a vertical position using a rotary atomizing electrostatic coating machine to a cured film thickness of 15 µm. The resulting test substrate was allowed to stand for 5 minutes and then preheated in a vertical position to 80°C for 3 minutes. Subsequently, paint composition No. 1 was electrostatically applied to the uncured basecoat film in a vertical position using a rotary atomizing electrostatic coating machine to a dry film thickness of 45 µm to form a clear coating film.The resulting product was left to stand for 7 minutes and heated to 140°C for 30 minutes (holding time) in a vertical state to cure the base coating film and the transparent coating film, thus preparing a test panel of example 10. Test panels of paint compositions No. 2 to 28 were prepared in the same way as in the preparation of the test panel of paint composition No. 1, except that each of the paint compositions No. 2 to 28 was used. nzopnn / ίζηζ / ε / γίΛΐ Preparation of the test panel for the evaluation of buckling resistance Elecron GT-10 (trade name, produced by Kansai Paint Co., Ltd., cationic electroplating paint) was applied by electroplating to a zinc phosphate-treated cold-rolled steel plate (11 cm x 45 cm) to a dry film thickness of 20 µm and cured by heating to 170°C for 30 minutes. Subsequently, WP-306T (trade name, produced by Kansai Paint Co., Ltd., melamine polyester resin-based aqueous intermediate paint) was electrostatically applied to the electroplating film using a rotary atomizing electrostatic coating machine to a cured film thickness of 30 µm and allowed to rest for 5 minutes, followed by preheating to 80°C for 3 minutes and then heating to 140°C for 30 minutes, thus preparing a test substrate.Subsequently, 21 perforations with a diameter of 5 mm were formed in a row at 2 cm intervals, 3 cm from the edge, on one longitudinal side of the test substrate. Then, WBC-713T No. 202 (trade name, produced by Kansai Paint Co., Ltd., waterborne acrylic melamine resin-based basecoat paint, coating color: black) was electrostatically applied to the vertically held test substrate using a rotary atomizing electrostatic coating machine to a cured film thickness of 15 µm. The resulting test substrate was allowed to stand for 5 minutes and then preheated vertically to 80°C for 3 minutes. Next, paint composition No.1. The uncured coating film was applied in a vertical state using a rotary atomizing electrostatic coating machine to a film thickness of approximately 30 µm to 60 µm with a gradient in the longitudinal direction. The resulting product was allowed to stand for 7 minutes at room temperature and then heated to 140°C for 30 minutes (holding time) in a vertical state to cure the base coating film and the clear coating film, thus preparing a test panel of Example 10. Test panels of paint compositions No. 2 to 28 were prepared in the same way as in the preparation of the test panel of paint composition No. 1, except that each of the paint compositions No. 2 to 28 was used. The previously obtained test panels were evaluated using the test methods described below. Table 2 shows the evaluation results along with the paint composition formulations. Test Method 1 Finished appearance: The final appearance of each test panel was evaluated based on a long wave (LW) value measured using a wave scanner (trade name, produced by BYK Gardner). The lower the LW value, the smoother the coating surface. Water reddening resistance: The water reddening resistance of each test panel was evaluated based on the difference in L* values ​​measured with a CM-512m3 (trade name, produced by Konica Minolta, Inc., a multi-angle spectrophotometer) before and after immersion in hot water. In this test, the L* value was obtained by summing the L* values ​​obtained when the panel was illuminated with standard D65 illuminant from three angles, i.e., 25° (highlighting direction), 45°, and 75° (bottom direction), with respect to the angle of reception (the direction perpendicular to the coated surface was considered 0°). After the L* values ​​were measured, the test panel was immersed in hot water at 5 to 40°C for 10 days. The L* values ​​of the test panel were measured after immersion, and the difference AL* between the L* values ​​before and after immersion was calculated.A smaller AL* value indicates less reddening of the coating due to immersion in hot water and represents greater resistance to reddening with water. Buckling resistance: Each test panel was examined to determine the portions where buckling of 3 mm or more of the coating composition began to be observed from the bottom of each drilled hole. Buckling resistance was evaluated by measuring the film thickness (buckling limit film thickness (pm)) in these portions. The greater the buckling limit film thickness, the better the buckling resistance. nzopnn / Lznz / B / YiAi TABLE 2 Example 10 11 12 13 14 15 16 Paint Composition No. 1 2 3 4 5 6 7 Main Agent Binder Component (B) Hydroxy-Containing Resin (Bl) Hydroxy-Containing Acrylic Resin (Bl1) Hydroxy-Containing Acrylic Resin (Bl-1-1) 51.5 51.5 51.5 51.5 51.5 41.5 45.5 Crosslinking Agent (B2) Amino Resin U-VAN 20SE60 4 4 4 4 4 4 Rheology Control Agent Dispersion Name AM1 AM2 AM3 AM4 AM5 AM6 AM6 Quantity 10 10 10 10 10 20 20 Surface Adjustment Agent BYK-300 0.2 0.2 0.2 0.2 0.2 0.2 0.2 NACURE 5523 Catalyst 0.1 0.1 0.1 0.1 0.1 0.1 Curing Agent Binder Component (B) Crosslinking Agent (B2) Sumidur N3300 Polyisocyanate Compound 35 35 35 35 35 35 35 Content of Components (A) and (B) (parts by mass) Binder Component (B) Hydroxy-Containing Resin (B1) 61 61 61 61 61 61 65 Crosslinking Agent (B2) 39 39 39 39 39 39 35 Rheology Control Agent (A) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Results Finished Appearance (LW) 7.5 7.1 6.9 6.7 6.7 6.5 6.7. Evaluation Buckling resistance (pm) 47 48 48 50 49 50 51 Water reddening resistance (AL*) 0.2 0.1 0.1 0.0 0.0 0.0 0.0 TABLE 2 (continued-l) Example 17 18 19 20 21 22 Paint Composition No. 8 9 10 11 12 13 Main Agent Binder Component (B) Hydroxy-containing resin (Bl) Hydroxy-containing acrylic resin (Bl-1) Hydroxy-containing acrylic resin (Bl1-D) 45.5 22 2.5 51.5 51.5 51.5 Crosslinking Agent (B2) Amino resin U-VAN 20SE60 35 4 4 4 4 4 Rheology Control Agent Dispersion Name AM-6 AM-6 AM-6 AM-7 AM-8 AM-9 Quantity 20 40 60 10 10 10 Surface Adjustment Agent BYK-300 0.2 0.2 0.2 0.2 0.2 0.2 Catalyst NACURE 5523 0.1 0.1 0.1 0.1 0.1 0.1 Curing Agent Binder Component (B) Crosslinking Agent (B2) Polyisocyanate Compound Sumidur N3300 35 35 35 35 35 Content of components (A) and (B) (parts by mass) Binder Component (B) Hydroxy-containing resin (B1) 65 61 61 61 61 61 Crosslinking Agent (B2) 35 39 39 39 39 39 Rheology Control Agent (A) 0.5 1.0 1.5 0.5 0.5 0.5 Evaluation Results Finished Appearance (LW) 6.9 7.3 8.0 6.8 7.0 6.8 Buckling resistance (pm) 50 51 52 51 50 49 Water reddening resistance (AL*) 0.0 0.1 0.3 0.0 0.1 0.0. TABLE 2 (continued-2) Example 23 24 25 26 Paint Composition No. 14 15 16 17 Main Agent Binder Component (B) Hydroxy-Containing Resin (Bl) Hydroxy-Containing Acrylic Resin (Bl1) Hydroxy-Containing Acrylic Resin (Bl-1-1) 41.5 41.5 41.5 41.5 Crosslinking Agent (B2) Amino Resin U-VAN 20SE60 4 4 4 4 Dispersion of Rheology Control Agent Name AM-6 AM-6 AM-6 AM-6 Quantity 20 20 20 20 Surface Adjustment Agent BYK-300 0.2 0.2 0.2 0.2 Ultraviolet absorber Γ TINUVIN 400 J (*6) 3 3 3 3 Light stabilizer THOSTAVIN 3058J (*7) 1 1 1 1 Catalyst NACURE 5523 0.1 ΓNACURE 4167 J (*8) 0.1 NEOSTANN U-600 (*9) 0.1 Curing agent Binder component (B) Crosslinking agent (B2) Polyisocyanate compound Sumidur N3300 35 35 35 35 Content of components (A) and (B) (parts by mass) Binder component (B) Hydroxy-containing resin (B1) 61 61 61 61 Crosslinking agent (B2) 39 39 39 39 Rheology control agent (A) 0.5 0.5 0.5 0.5 Evaluation Results Finished Appearance (LW) 6.5 6.6 6.5 6.8 Buckling Resistance 50.0 50.0 49.0 49.0 Water Reddening Resistance (AL*) 0.0 0.0 0.0 0.0 nzoAnn / Lznz / E / γΐΛΐ TABLE 2 (continued-3) Comparative Example 9 10 11 12 13 14 Paint Composition No. 18 19 20 21 22 23 Main Agent Binder Component (B) Hydroxy-Containing Resin (Bl) Hydroxy-Containing Acrylic Resin (Bl-1) Hydroxy-Containing Acrylic Resin (Bl-1-1) 51.5 51.5 51.5 51.5 51.5 51.5 Crosslinking Agent (B2) Amino Resin U-VAN 20SE60 4 4 4 4 4 4 Rheology Control Agent Dispersion Name AM-10 AM-11 AM-12 AM-13 AM-14 AM-15 Quantity 10 10 10 10 10 10 Surface Adjustment Agent BYK-300 0.2 0.2 0.2 0.2 0.2 0.2 NACURE 5523 Catalyst 0.1 0.1 0.1 0.1 0.1 0.1 Curing Agent Binder (B) Crosslinking Agent (B2) Polyisocyanate Compound Sumidur N3300 35 35 35 35 35 35 Content of components (A) and (B) (by mass) Binder (B) Hydroxy-containing resin (B1) 61 61 61 61 61 61 Crosslinking Agent (B2) 39 39 39 39 39 39 Rheology Control Agent (A) 0.5 0.5 0.5 0.5 0.5 0.5 Evaluation results Finished appearance (LW) 10.5 (Bow o) 10.2 (Bow o) 10.4 (Bow o) 13.2 (Bow o) 10.8 (Bow o) 11.8 (Bow o) Buckling resistance 43.0 44.0 44.0 43.0 42.0 41.0 Water reddening resistance (AL*) 0.7 0.5 0.6 0.9 0.6 0.6 TABLE 2 (continued^) nzoann / ίζηζ / ε / γίΛΐ Comparative Example 15 16 17 18 19 Paint Composition No. 24 25 26 27 28 Main Agent Binder Component (B) Hydroxy-Containing Resin (Bl) Hydroxy-Containing Acrylic Resin (Bl1) Hydroxy-Containing Acrylic Resin (Bl-1-1) 56.5 43 25 56.5 41.5 Crosslinking Agent (B2) Amino Resin U-VAN 20SE60 4 4 4 4 4 Rheology Control Agent Dispersion Name AM-16 AM-16 AM-16 AM-17 AM-17 Quantity 5 20 40 5 20 Surface Adjustment Agent BYK-300 0.2 0.2 0.2 0.2 0.2 Catalyst NACURE 5523 0.1 0.1 0.1 0.1 0.1 Curing Agent Binder Component (B) Crosslinking Agent (B2) Sumidur N3300 Polyisocyanate Compound 35 35 35 35 35 Content of components (A) and (B) (parts by mass) Binder Component (B) Hydroxy-containing resin (B1) 61 61 61 61 61 Crosslinking Agent (B2) 39 39 39 39 39 Rheology Control Agent (A) 0.5 2.0 4.0 0.5 2.0 Evaluation Results Finished Appearance (LW) 11.0 (Buckling) 10.6 10.5 11.6 (Buckling) 10.2 Buckling resistance 42.0 46.0 49.0 41.0 47.0 Water reddening resistance (AL*) 0.6 1.3 2.2 0.6 1.7. The asterisks (*) in Table 2 mean the following. *6: TINUVIN 400: Trade name, benzotriazole ultraviolet ray absorber, active ingredient: 100%, produced by BASF *7: HOSTAVIN 3058: Trade name, hindered amine light stabilizer, hindered amine, active ingredient: 100%, produced by Clariant *8: NACURE 4167: Trade name, triethylamine salt of alkylphosphoric acid, active ingredient: 25%, produced by King Industries, Inc. *9: NEOSTANN U-600: trade name, inorganic bismuth, active ingredient: 100%, produced by Nitto Kasei Co., Ltd. Paint Composition Production: Part 2 EXAMPLE 27 32.5 parts (solids content: 19.5 parts) of the hydroxy-containing acrylic resin solution (Bl-1-1) obtained from production example 1, 33.8 parts (solids content: 22 parts) of the hydroxy-containing acrylic resin solution (Bl-1-2) obtained from production example 2, 6.7 parts (solids content: 4 parts) of U-VAN 20SE60 (trade name, produced by Mitsui Chemicals, Inc., a melamine resin, solids content: 60%), 40 parts (solids content: 20 parts, wherein the rheology control agent component (A) constitutes 0.5 parts, and the hydroxy-containing acrylic resin (Bl-1-1) constitutes 19.5 parts) of the rheology control agent dispersion solution (AM-6) obtained from example 6, 0.4 parts (solids content of solids: 0.2 parts) of BYK-300 (trade name, produced by BYK-Chemie, a surface adjusting agent, active ingredient: 52%) and 0.3 parts (solids content: 0.1 part) of NACURE 5523 (trade name, dodecylbenzenesulonic acid amine salt, active ingredient: 35%, produced by King Industries, Inc.) were uniformly mixed to obtain a main agent. The main agent and 35 parts of Sumidur N3300 (trade name, produced by Sumika Covestro Urethane Co., Ltd., a hexamethylene diisocyanurate isocyanurate, solids content: 100%), which is a curing agent (crosslinking agent (B2)), were mixed uniformly immediately before application, and butyl acetate was added to adjust the viscosity to 30 seconds, measured with a Ford Cup No. 4 at 20°C, thus obtaining paint composition No. 29. EXAMPLES 28 to 29 and COMPARATIVE EXAMPLE 20 Paint compositions No. 30 to 32 with a viscosity of 30 seconds, measured with a No. 4 Ford Cup at 20°C, were obtained in the same manner as in Example TJ, except that the formulations shown in Table 3 below were used. The quantities of the components shown in Table 3 are expressed as solids content by mass. Test panel preparation: Part 2 Test panel preparation for examples 27 to 29 and comparative example 20 Preparation of the test panel for the evaluation of the finish appearance, resistance to water reddening and scratch resistance The test panels for paint compositions No. 29 to 32 were prepared in the same way as in the preparation of the test panel for the evaluation of the final appearance and resistance to water reddening described in the section Preparation of the test panel: Part 1, except that each of the paint compositions No. 29 to 32 was used. Preparation of the test panel for the evaluation of buckling resistance The test panels for paint compositions No. 29 to 32 were prepared in the same manner as in the preparation of the test panel for the evaluation of buckling resistance in the section Preparation of the test panel: Part 1, except that each of the paint compositions No. 29 to 32 was used. The previously obtained test panels were evaluated using the test methods described below. Table 3 shows the evaluation results along with the paint composition formulations. Test Method 2 The final appearance, resistance to water reddening, and resistance to buckling were evaluated in the same manner as described above in Test Method 1. Scratch Resistance: Each test panel was affixed to the roof of a car using waterproof adhesive tape (produced by Nichiban Co., Ltd.), and the car, with the test panel on the roof, was washed 15 times in a car wash tunnel at 20°C. The 20° specular reflectance (20° gloss) of the test panel was then measured, and the gloss retention (%) was calculated relative to the 20° gloss value before the test to assess scratch resistance. The higher the gloss retention, the better the scratch resistance. In this specification, an evaluation result of A, B, or C signifies excellent scratch resistance. The car wash tunnel used was a PO20 FWRC (produced by Yasui Sangyo KK). A: 80% or more gloss retention B: Gloss retention of 75% or more and less than 80% C: Gloss retention of 70% or more and less than 75% D: Gloss retention of 50% or more and less than 70% E: Gloss retention less than 50% nzo«nn / Lznz / B / YiAi TABLE 3 Example Comparative Example 27 28 29 20 Paint Composition No. 29 30 31 32 Main Agent Binder Component (B) Hydroxy-Containing Resin (B1) Hydroxy-Containing Acrylic Resin (B1-1) Hydroxy-Containing Acrylic Resin (B1-12) 19.5 9.5 19.5 34.5 Hydroxy- and Alkoxysilyl-Containing Secondary Acrylic Resin (B1-2) 22 32 22 Hydroxy- and Alkoxysilyl-Containing Primary Acrylic Resin (B1-3) 22 Crosslinking Agent (B2) Amino Resin U-VAN 20SE60 4 4 4 4 Dispersion of Rheology Control Agent Name AM-6 AM-6 AM-6 AM-17 Quantity 20 20 20 5 Surface Adjustment Agent BYK-300 0.2 0.2 0.2 0.2 NACURE5523 Catalyst 0.1 0.1 0.1 0.1 Curing Agent Binder Component (B) Crosslinking Agent (B2) Sumidur N3300 Polyisocyanate Compound 35 35 35 35 Content of Components (A) and (B) (parts by mass) Binder Component (B) Nidroxy-Containing Acrylic Resin (B1-11) 39 29 29 39 Hydroxy- and Alkoxysilyl-Containing Secondary Acrylic Resin (B1-12) 22 32 32 22 Crosslinking Agent (B2) 39 39 39 39 Rheology Control Agent (A) 0.5 0.5 0.5 0.5 Evaluation Results Finished Appearance (LW) 6.7 7.5 6.9 11.5 (Buckling) Buckling Resistance 50 51 49 43 Water Reddening Resistance (AL*) 0.0 0.0 0.0 0.6 Scratch resistance. BAB B. nzopnn / Lznz / B / YiAi The embodiments and examples of the present invention are described in detail above. However, the present invention is not limited to these embodiments, and various modifications can be made based on the technical idea of ​​the present invention. For example, the structures, methods, steps, forms, materials, and values ​​indicated in the modalities and examples above are simply examples, and different structures, methods, steps, forms, materials, values, and the like may also be used as needed. Furthermore, the structures, methods, stages, forms, materials, values ​​and the like indicated in the modalities can be combined interchangeably without departing from the spirit and main concepts of the present invention. Furthermore, the present invention may also utilize the following structures. [1] A rheology control agent comprising a reaction product of a polyisocyanate compound (a1), a primary monoamine having a number-average molecular weight of 300 or less (a2), and a polyetheramine having two or more amino groups and having a number-average molecular weight of 1000 or more and less than 6000 (a3), wherein the proportion of polyetheramine having a number-average molecular weight of 1000 or more and less than 6000 (a3) ​​is within a range of 10 to 30% by mass based on the total amount of components (a1) to (a3). [2] The rheology control agent according to [1], wherein the polyether amine (a3) ​​has three or more amino groups. [3] The rheology control agent according to [1] or [2], wherein the proportion of polyether amine (a3) ​​is more than 15% by mass and 30% by mass or less on a basis of the total amount of components (al) to (a3). [4] The rheology control agent according to any of [1] to [3], wherein the proportion of the polyisocyanate compound (al) is from 30% by mass to 60% by mass based on the total amount of components (al) to (a3). [5] The rheology control agent according to any of [1] to [4], wherein the polyisocyanate compound (al) is an aliphatic diisocyanate compound and / or an isocyanurate. [6] The rheology control agent according to any of [1] to [5], wherein the proportion of the primary monoamine having a number average molecular weight of 300 or less (a2) is 30% by mass to 60% by mass based on the total amount of components (a1) to (a3). [7] The rheology control agent according to any of [1] to [6], wherein the primary monoamine having a number average molecular weight of 300 or less (a2) is a primary amine having a benzene ring. [8] The rheology control agent according to any of [1] and [3] to [7], wherein the polyether amine (a3) ​​is a polyoxyalkylene-containing diamine represented by formula (1): H2N—R3—lO—R4-|---NH2(l)L Jn where R3 represents a C2+ alkylene group, R4 represents a C2-6 alkylene group, n represents an integer from 9 to 134, and n oxyalkylene (O-R4) units can be the same or different; when the oxyalkylene (O-R4) units are different from each other, the addition form (polymerization form) of the oxyalkylene (O-R4) units can be a random form or a block form. [9] The rheology control agent according to [8], wherein the polyether amine (a3) ​​is a polyoxyalkylene-containing diamine represented by the following formula (2) nzo«nn / ίζηζ / ε / γίΛΐ ch3ch3 where c represents an integer from 16 to 102, and / or a polyoxyalkylene-containing diamine represented by the following formula (3) CH3ch3ch3where dyf each represent an integer from 1 to 20, e represents an integer from 12 to 60, and d+f is within an interval from 2 to 40.

[10] The rheology control agent according to any of [1] to [7], wherein the polyether amine (a3) ​​is a polyoxyalkylene-containing polyamine having three or more amino groups represented by the following formula (4) (4) where R5 represents a q-valent organic group having a carbon atom in a bonding site with the oxygen atom indicated in the formula; R6 represents a Cz-e alkylene group; p represents an integer from 4 to 45; q represents an integer of 3 or more; p oxyalkylene (O-R6) units may be the same or different; when the oxyalkylene (O-R6) units are different from each other, the addition form (polymerization form) of the oxyalkylene (O-R6) units may be a random form or a block form.

[11] The rheology control agent according to

[10] , wherein the polyether amine (a3) ​​is a triamine containing polyoxyalkylene represented by the following formula (5) (5) nzo«nn / ίζηζ / ε / γίΛΐ where j, k and r each represent an integer from 5 to 60.

[12] A paint composition comprising (A) the rheology control agent of any of [1] to

[11] , and (B) a binder component.

[13] The paint composition according to

[12] , wherein the binder component (B) contains a hydroxy-containing resin (B1) and a crosslinking agent (B2).

[14] The paint composition according to

[13] , wherein the hydroxy-containing resin (Bl) is an acrylic resin containing hydroxy (Bl-1).

[15] The paint composition according to

[13] or

[14] , wherein the hydroxy-containing resin (Bl) is a secondary hydroxy-containing acrylic resin (Bl-la).

[16] The paint composition according to any of

[13] to

[15] , wherein the hydroxy-containing resin (Bl) contains an acrylic resin containing hydroxy and alkoxysilyl (Bl-lb).

[17] The paint composition according to any of

[13] to

[16] , wherein the hydroxy-containing resin (Bl) contains a secondary acrylic resin containing hydroxy and alkoxysilyl (Bl-lc).

[18] The paint composition according to any of

[13] to

[17] , wherein the crosslinking agent (B2) contains one, two or more polyisocyanate compounds.

[19] The paint composition according to any of

[13] to

[17] , wherein the crosslinking agent (B2) contains a blocked polyisocyanate compound, and the content of the blocked polyisocyanate compound is 5 to 60 parts by mass, per 100 parts by mass of the solids content of the binder component.

[20] The paint composition according to any of

[13] to

[17] , wherein the crosslinking agent (B2) contains an amino resin, and the amino resin content is from 0.5 to 40 parts by mass, per 100 parts by mass of the solids content of the binder component.

[21] The paint composition according to any of (12) to (20), wherein the content of the rheology control agent (A) is within a range of 0.1 to 2 parts by mass, per 100 parts by mass of the total solids content of the binder component (B).

Claims

1. A rheology control agent comprising a reaction product of a polyisocyanate compound (a1), a primary monoamine having a number-average molecular weight of 300 or less (a2), and a polyetheramine having two or more amino groups and having a number-average molecular weight of 1000 or more and less than 6000 (a3), wherein the proportion of polyetheramine having a number-average molecular weight of 1000 or more and less than 6000 (a3) ​​is within a range of 10 to 30% by mass based on the total amount of components (a1) to (a3).

2. The rheology control agent according to claim 1, further characterized in that the polyether amine (a3) ​​has three or more amino groups.

3. The rheology control agent according to claim 1 or 2, further characterized in that the proportion of polyether amine (a3) ​​is more than 15% by mass and 30% by mass or less on a basis of the total amount of components (al) to (a3).

4. A paint composition comprising (A) the rheology control agent of any of claims 1 to 3, and (B) a binder component.

5. The paint composition according to claim 4, further characterized in that the binder component (B) contains a hydroxy-containing resin (B1) and a crosslinking agent (B2).