Urethane resin composition, paint composition, laminate

Abstract

The present invention provides a urethane resin composition capable of forming a hard coat layer with excellent scratch resistance, good storage stability, and excellent adhesion to a substrate; a paint composition comprising the urethane resin composition; a cured product of the urethane resin composition; and a laminate formed by stacking the cured products. [Solution] A urethane resin composition comprising a polyol (A), a polyisocyanate (B), and inorganic fine particles (C), wherein the hydroxyl value of the polyol (A) is 20 to 300 mgKOH / g, the inorganic fine particles (C) have a functional group that can react with a hydroxyl group or an isocyanate group, and the proportion of the inorganic fine particles (C) is 5 to 100 parts by weight per 100 parts by weight of the polyol (A).

Description

Technical Field

[0001] The present invention relates to a urethane resin composition, a coating composition, and a laminate.

Background Art

[0002] Generally, molded articles made of polycarbonate resin, polymethyl methacrylate resin, or polystyrene resin are not only lightweight and excellent in moldability, but also have good transparency and are superior in impact resistance compared to glass products. Therefore, polycarbonate resin, polymethyl methacrylate resin, and polystyrene resin are used as glass substitute materials in various lamp lenses, window materials, covers for instruments, etc. In particular, for headlamp lenses, plastic materials are used due to the diversification of automobile designs. In recent years, polycarbonate resin molded articles with excellent impact resistance are used for window glass and sunroofs for vehicle weight reduction.

[0003] However, since polycarbonate resin molded articles lack surface abrasion resistance and scratch resistance, they are easily damaged on the surface by contact, friction, scratching, etc. with other hard objects, and the damage generated on the surface will reduce the commercial value of the product.

[0004] In order to compensate for such drawbacks of polycarbonate resin molded articles, a coating composition obtained by adding an ultraviolet absorber to a curable raw material such as an acrylic-based, melamine-based, urethane-based, or silicon-based material with relatively excellent weather resistance is applied to the surface of the molded article and heated to form a cured film, or irradiated with active energy rays such as ultraviolet rays or electron beams to cure and form a cured film with weather resistance. Among them, the curing method of a thermosetting paint in a hot drying furnace has advantages such as easy uniform heating regardless of the three-dimensional shape of the coated object, and the obtained cured film is likely to exhibit stable performance regardless of the site.

[0005] As a method of forming a thermosetting cured film on the surface of a resin molded article, it is known to coat with a paint containing a urethane resin composition.

[0006] Patent Document 1 describes a urethane coating composition containing a specific polyol compound, a polyisocyanate compound, and silica particles; Patent Document 2 describes a coating composition containing resin-coated silica particles in which silica particles are coated with a hydroxyl group-containing acrylic resin; and Patent Document 3 describes a thermosetting composition containing colloidal silica modified with a specific silane coupling agent. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2012-021111 [Patent Document 2] Japanese Patent Publication No. 2013-001897 [Patent Document 3] Japanese Patent Publication No. 2020-132751 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The hard coat layer described in Patent Document 1 is said to have excellent scratch resistance by blending a predetermined ratio of acrylic polyol and silica particles, but it is insufficient to meet the recent demand for higher scratch resistance. Regarding the paint composition described in Patent Document 2, a paint composition containing resin-coated silica particles made of hydroxyl group-containing acrylic resin and silica particles has been proposed, but the resin-coated silica particles cause aggregation in the paint, resulting in poor storage stability. Regarding Patent Document 3, although it has excellent abrasion resistance by blending a predetermined ratio of polyol and silica particles having reactive functional groups, the coating film lacks flexibility, which may lead to peeling or cracking of the hard coat layer.

[0009] The present invention aims to provide a urethane resin composition capable of forming a hard coat layer with excellent scratch resistance, good storage stability, and excellent adhesion to a substrate; a paint composition comprising the urethane resin composition; a cured product obtained by curing the paint composition; and a laminate in which the cured products are laminated. [Means for solving the problem]

[0010] The present invention has the following aspects. In other words, the above objectives of the present invention can be achieved by the following means [1] to

[15] . [1] A urethane resin composition comprising a polyol (A), a polyisocyanate (B), and inorganic fine particles (C), wherein the hydroxyl value of the polyol (A) is 20 to 300 mgKOH / g, the inorganic fine particles (C) have a functional group that can react with a hydroxyl group or an isocyanate group, and the proportion of the inorganic fine particles (C) is 5 to 100 parts by weight per 100 parts by weight of the polyol (A). [2] The urethane resin composition according to [1], wherein the inorganic fine particles (C) are colloidal silica modified with a silane coupling agent. [3] The urethane resin composition according to [1] or [2], wherein the reactive group of the inorganic fine particles (C) is one of an isocyanate group, an epoxy group, or a mercapto group. [4] The urethane resin composition according to any one of the items [1] to [3], wherein the polyol (A) is either an acrylic polyol or a polyester polyol. [5] The urethane resin composition according to any one of [1] to [4], wherein the solubility parameter of the polyol (A) is 8.0 or more and 12.0 or less. [6] The urethane resin composition according to any one of [1] to [5], wherein the glass transition temperature of the polyol (A) is -40°C or higher and 100°C or lower. [7] The urethane resin composition according to any one of [1] to [6], wherein the weight-average molecular weight of the polyol (A) is 900 or more and less than 200,000. [8] A urethane resin composition according to any one of the items [1] to [7], comprising a polycarbonate polyol (D) in addition to the polyol (A). [9] The urethane resin composition according to any one of [1] to [8], wherein the urethane resin composition comprises an ultraviolet absorber (E).

[10] The urethane resin composition according to any one of the items [1] to [9], wherein the ultraviolet absorber (E) is hydroxyphenyltriazine-based.

[11] The urethane resin composition according to any one of [1] to

[10] , wherein the urethane resin composition comprises a hindered amine-based light stabilizer (F). A paint composition comprising the urethane resin composition described in any one of items

[12] [1] to

[11] . A cured product obtained by curing a urethane resin composition described in any one of items

[13] [1] to

[11] . A cured product obtained by applying a urethane resin composition described in any one of items

[14] [1] to

[11] onto a polycarbonate resin substrate and drying it in a 120°C atmosphere for 30 minutes, wherein the film thickness of the cured product is 5 to 30 μm, and the scratch hardness conforming to JIS 5600-5-4 is HB or higher. A laminate having a coating film made of the cured product described in

[15] ,

[13] , or

[14] . [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a urethane resin composition that can form a hard coat layer with excellent scratch resistance, good storage stability, and excellent adhesion to a substrate, a paint composition made from the urethane resin composition, a cured product obtained by curing the paint composition, and a laminate in which the cured products are laminated. [Modes for carrying out the invention]

[0012] The embodiments of the present invention will be described in detail below, but the following description is merely one example of an embodiment of the present invention, and the present invention is not limited to the following description unless it exceeds the gist of the invention. In addition, when the expression "~" is used in this specification, it shall be used as an expression including the numerical values or physical property values before and after it. Further, in the present invention, when the expression "(meth)acryl" is used, it shall mean one or both of "acryl" and "methacryl". The same applies to "(meth)acrylate", "(meth)acryloyl", etc.

[0013] <Urethane resin composition> The urethane resin composition of the present invention is a urethane resin composition containing a polyol (A), a polyisocyanate (B), and inorganic fine particles (C), wherein the hydroxyl value of the polyol (A) is 20 to 300 mgKOH / g, the inorganic fine particles (C) have a functional group capable of reacting with a hydroxyl group or an isocyanate group, and the proportion of the inorganic fine particles (C) is 5 to 100 parts by weight with respect to 100 parts by weight of the polyol (A).

[0014] <Polyol (A)> The polyol (A) has a hydroxyl value within the range of 20 to 300 mgKOH / g and is a compound having two or more hydroxyl groups in one molecule. However, it excludes the polycarbonate polyol (D) described later.

[0015] From the viewpoints of the pot life of the resin composition, compatibility with other components, and scratch resistance, chemical resistance, and adhesion of the formed coating film, the hydroxyl value of the polyol (A) is usually in the range of 20 to 300 mgKOH / g, preferably 45 to 280 mgKOH / g, more preferably 60 to 250 mgKOH / g, still more preferably 80 to 220 mgKOH / g, and most preferably 100 to 210 mgKOH / g. By using within the corresponding range, the scratch resistance of the coating film becomes good. When the hydroxyl value of the polyol (A) is less than 20 mgKOH / g, the scratch resistance decreases, and when it is 300 mgKOH / g or more, the substrate adhesion decreases. The hydroxyl value can be measured, for example, by reacting the polyol (A) with an excess of acetic anhydride in pyridine and titrating the liberated acetic acid with potassium hydroxide.

[0016] Also, the solubility parameter (SP value) of the polyol (A) is usually in the range of 8.0 to 12.0, preferably 8.5 to 11.5, more preferably 8.8 to 11.0, and most preferably 9.0 to 10.5 in order to ensure compatibility with other components such as the polyisocyanate (B), inorganic fine particles (C), and ultraviolet absorber (E). By using it within the applicable range, compatibility between the polyol (A) and other components is ensured, and scratch resistance and weather resistance are improved. When the SP value of the polyol (A) is less than 8.0, compatibility with the inorganic fine particles (C) and the ultraviolet absorber (E) decreases, and scratch resistance and weather resistance become low. When the SP value of the polyol (A) is greater than 12.0, compatibility with the polyisocyanate (B) decreases, causing poor appearance and reduced scratch resistance.

[0017] Here, the SP value is a measure of solubility and is measured as follows. Reference: SUH, CLARKE [J.P.S.A-1, 5, 1671-1681 (1967)]. · Measurement temperature: 20 °C · Sample: Weigh 0.5 g of the resin into a 100 ml beaker, add 10 ml of a good solvent using a pipette, and dissolve it using a magnetic stirrer. · Solvent: Good solvent: Acetone. Poor solvent: n-Hexane, ion-exchanged water. · Cloud point measurement: Using a 50 ml burette, dropwise add the poor solvent, and take the dropping amount at the point where turbidity occurs. · Calculation: The SP value δ of the resin is given by the following formula.

[0018]

Number

[0019] Furthermore, the glass transition temperature (Tg) of polyol (A) is typically -40 to 100°C, preferably 0 to 95°C, more preferably 15 to 90°C, and most preferably 24 to 70°C, in order to achieve both indentation hardness and scratch resistance. By using it within this range, good indentation hardness and scratch resistance can be achieved. If the Tg is lower than -40°C, the indentation hardness decreases, and if it is higher than 100°C, the scratch resistance decreases and the appearance of the coating film deteriorates. Here, the Tg of polyol can be measured using a differential scanning calorimeter (DSC). Specific measurement conditions are shown in the examples below.

[0020] Furthermore, the weight-average molecular weight (Mw) of polyol (A) should be appropriately selected depending on the application of the resin composition, but is preferably in the range of 900 to 200,000, more preferably 1,000 to 50,000, even more preferably 1,800 to 20,000, and particularly preferably 5,000 to 10,000. Using this range makes it possible to achieve both scratch resistance and indentation hardness, and also makes it easier to set the viscosity of the composition within an appropriate range, resulting in good leveling properties during film formation. The weight-average molecular weight (Mw) can be determined using gel permeation chromatography (GPC) as a converted value based on the polystyrene standard. Specific measurement conditions are shown in the examples below.

[0021] As polyols that satisfy the above requirements, resins such as acrylic polyols, polyester polyols, and polyether polyols can be used. Among these, acrylic polyols and polyester polyols are preferred from the viewpoint of being easy to adjust the hydroxyl value and forming a hard coat layer with good weather resistance, and acrylic polyols are the most preferred. These polyols may be used individually or in combination of two or more types.

[0022] <Acrylic polyol> Acrylic polyols can be obtained, for example, by copolymerizing a monomer (a1) having one or more hydroxyl groups in one molecule and an ethylenically unsaturated bond with another ethylenically unsaturated monomer (a2) that can copolymerize with it.

[0023] Monomers (a1) having one or more hydroxyl groups in one molecule and an ethylenically unsaturated bond include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol (meth)acrylate, cyclohexanedimethanol mono(meth)acrylate, caprolactone adduct monomers such as the "Praxel F" series (a caprolactone adduct monomer manufactured by Daicel Corporation, trade name), and "Bremmer PME-100" (a methoxypolyethylene glycol methacrylate monomer manufactured by NOF Corporation). Examples include glycol ester monomers such as acrylate (ethylene glycol with 2 chains), trade name, "Bremmer PME-200" (manufactured by NOF Corporation), methoxypolyethylene glycol methacrylate (ethylene glycol with 4 chains), trade name, "Bremmer PME-400" (manufactured by NOF Corporation), methoxypolyethylene glycol methacrylate (ethylene glycol with 9 chains), trade name, "Bremmer AME-100" (manufactured by NOF Corporation, trade name), "Bremmer AME-200" (manufactured by NOF Corporation, trade name), and "Bremmer 50AOEP-800B" (manufactured by NOF Corporation, trade name), and other hydroxyl group-containing (meth)acrylic acid esters.

[0024] As monomer (a1), 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, Praxel FM1 (manufactured by Daicel Corporation, 1 mol caprolactone-added monomer of 2-hydroxyethyl methacrylate, trade name), Praxel FM2 (manufactured by Daicel Corporation, 1 mol caprolactone-added monomer of 2-hydroxyethyl methacrylate, trade name), Praxel FA1 (manufactured by Daicel Corporation, 1 mol caprolactone-added monomer of 2-hydroxyethyl acrylate, trade name), and Praxel FA2D (manufactured by Daicel Corporation, 1 mol caprolactone-added monomer of 2-hydroxyethyl acrylate, trade name) are preferred from the viewpoint of ease of availability and scratch resistance, and among these, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are particularly preferred.

[0025] The proportion of monomer (a1) in the acrylic polyol is typically in the range of 5 to 70% by mass, preferably 10 to 65% by mass, more preferably 14 to 58% by mass, even more preferably 18 to 51% by mass, and most preferably 25 to 52% by mass, relative to 100% by mass of the total constituent units of the acrylic polyol. By using within this range, an acrylic polyol having the desired hydroxyl value can be obtained.

[0026] Various other ethylenically unsaturated monomers can be copolymerized with monomers having one or more hydroxyl groups in a single molecule and containing an ethylenically unsaturated bond. Examples include the following monomers. Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, isoamyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isooctyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecyl methacrylate, lauryl methacrylate, tridecyl methacrylate, hexadecilate methacrylate (meth)acrylic acid esters containing hydrocarbon groups, including syl, stearyl (meth)acrylate, isostearyl (meth)acrylate, docosyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, 3,5,5-trimethylcyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, terpene acrylates and their derivatives, hydrogenated rosin acrylates and their derivatives; Carboxyl group-containing vinyl monomers such as (meth)acrylic acid, 2-(meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyloxypropyl phthalic acid, 2-(meth)acryloyloxyethyl maleic acid, 2-(meth)acryloyloxypropyl maleic acid, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxypropyl succinic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, monomethyl maleate, monoethyl maleate, monomethyl itaconic acid, monoethyl itaconic acid, monobutyl itaconic acid, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monoethyl citraconic acid, etc. Vinyl monomers containing acid anhydride groups such as maleic anhydride and itaconic anhydride; Amide-bonded vinyl monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, Nt-butyl(meth)acrylamide, Nt-octyl(meth)acrylamide, N-methylol(meth)acrylamide, hydroxyethyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, diacetone(meth)acrylamide, N,N-dimethylaminoethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, N-vinylacetamide, maleic acid amide, N,N'-methylenebis(meth)acrylamide, and other amide-bonded chain vinyl monomers; amide-bonded vinyl monomers such as (meth)acryloylmorpholin, N-vinylpyrrolidone, N-vinyl-ε-caprolactam, maleimide, and other amide-bonded cyclic vinyl monomers; Unsaturated dicarboxylic acid diester monomers such as dimethyl maleate, dibutyl maleate, dimethyl fumarate, dibutyl fumarate, dibutyl itaconate, and diperfluorocyclohexyl fumarate; Epoxy group-containing vinyl monomers such as glycidyl (meth)acrylate, glycidyl α-ethylacrylate, and 3,4-epoxybutyl (meth)acrylate; Amino group-containing (meth)acrylic acid ester monomers such as dimethylaminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate; Polyfunctional vinyl monomers such as divinylbenzene, ethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, allyl(meth)acrylate, triallyl cyanurate, diallyl maleate, and polypropylene glycol diallyl ether; Heterocyclic monomers such as vinylpyridine and vinylcarbazole; Monomers containing silane coupling agents such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane; Trimethylsilyl (meth)acrylate, triethylsilyl (meth)acrylate, tri-n-propylsilyl (meth)acrylate, tri-n-butylsilyl (meth)acrylate, tri-n-amylsilyl (meth)acrylate, tri-n-hexylsilyl (meth)acrylate, triphenylsilyl (meth)acrylate, tri-p-methylphenylsilyl (meth)acrylate, tribenzylsilyl (meth)acrylate, triisopropylsilyl (meth)acrylate, triisobutylsilyl (meth)acrylate, Tri-s-butylsilyl (meth)acrylate, tri-2-methylisopropylsilyl (meth)acrylate, tri-t-butylsilyl (meth)acrylate, ethyldimethylsilyl (meth)acrylate, n-butyldimethylsilyl (meth)acrylate, diisopropyl-n-butylsilyl (meth)acrylate, dicyclohexylphenylsilyl (meth)acrylate, t-butyldiphenylsilyl (meth)acrylate, triisopropylsilylmethylmalate, triisopropylsilylamylmalate, tri-n-butyl Lucilyl-n-butylmalate, t-butyldiphenylsilylmethylmalate, t-butyldiphenylsilyl-n-butylmalate, triisopropylsilylmethylfumarate, triisopropylsilylamylfumarate, tri-n-butylsilyl-n-butylfumarate, t-butyldiphenylsilylmethylfumarate, t-butyldiphenylsilyl-n-butylfumarate, Cylaprene FM-0711 (manufactured by JNC Corporation, product name), Cylaprene FM-0721 (manufactured by JNC Corporation, product name), Cylaprene FM-07 Organosilyl group-containing monomers other than silane coupling agent-containing monomers, such as 25 (manufactured by JNC Corporation, product name), Sylaprene TM-0701 (manufactured by JNC Corporation, product name), Sylaprene TM-0701T (manufactured by JNC Corporation, product name), X-22-174ASX (manufactured by Shin-Etsu Chemical Co., Ltd., product name), X-22-174BX (manufactured by Shin-Etsu Chemical Co., Ltd., product name), KF-2012 (manufactured by Shin-Etsu Chemical Co., Ltd., product name), X-22-2426 (manufactured by Shin-Etsu Chemical Co., Ltd., product name), X-22-2404 (manufactured by Shin-Etsu Chemical Co., Ltd., product name); Halogenated olefins such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and chlorotrifluoroethylene; Isocyanate group-containing monomers such as 2-isocyanatoethyl (meth)acrylate; 2,2,2-Trifluoroethyl (meth)acrylate, 2,2,3,3,3-Pentafluorophenyl (meth)acrylate, 2-(Perfluorobutyl)ethyl (meth)acrylate, 3-(Perfluorobutyl)-2-Hydroxypropyl (meth)acrylate, 2-(Perfluorohexyl)ethyl (meth)acrylate, 3-Perfluorohexyl-2-Hydroxypropyl (meth)acrylate, 3-(Perfluoro-3-Methylbutyl)-2-Hydroxypropyl (meth)acrylate, 2,2,3,3-Tetrafluoropropyl Fluorine-containing monomers such as (meth)acrylate, 1H,1H,5H-octafluoropentyl(meth)acrylate, 1H,1H,5H-octafluoropentyl(meth)methacrylate, 1H,1H,2H,2H-tridecafluorooctyl(meth)acrylate, 1H-1-(trifluoromethyl)trifluoroethyl(meth)acrylate, 1H,1H,3H-hexafluorobutyl(meth)acrylate, and 1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl(meth)acrylate (excluding halogenated olefins); Monomers with acetal structures such as 1-butoxyethyl (meth)acrylate, 1-(cyclohexyloxy)ethyl methacrylate, and 2-tetrahydropyranyl (meth)acrylate; Vinyl monomers such as 4-methacryloyloxybenzophenone, styrene, α-methylstyrene, vinyltoluene, (meth)acrylonitrile, vinyl acetate, and vinyl propionate. When using these monomers, there may be one monomer or two or more monomers.

[0027] As the monomer (a2), hydrocarbon-containing acrylic acid esters are preferred due to the ease of designing the SP value and Tg, and among these, monomers having alkyl groups with 1 to 13 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate, are preferred, and monomers having alkyl groups with 1 to 8 carbon atoms are even more preferred.

[0028] Furthermore, from the viewpoint of weather resistance, it is preferable that the content of aromatic monomers, such as styrene and benzyl (meth)acrylate, among the monomers (a2) is in the range of 0 to 30% by mass, more preferably in the range of 0 to 20% by mass, and even more preferably free of aromatic monomers, based on 100% by mass of the total constituent units of the acrylic polyol.

[0029] Monomer (a2) may contain a monomer having an acidic group. Examples of monomers having an acidic group include, but are not limited to, the following compounds. (Meth)acrylic acid, itaconic acid, citraconic acid, maleic acid, monomethyl maleate, monobutyl maleate, monomethyl itaconic acid, monobutyl itaconic acid, vinylbenzoic acid, monohydroxyethyl (meth)acrylate oxalate, monohydroxyethyl (meth)acrylate tetrahydrophthalate, monohydroxypropyl (meth)acrylate tetrahydrophthalate, monohydroxyethyl (meth)acrylate 5-methyl-1,2-cyclohexanedicarboxylic acid monohydroxyethyl (meth)acrylate, monohydroxyethyl (meth)acrylate phthalate, monohydroxypropyl (meth)acrylate phthalate, monohydroxyethyl (meth)acrylate maleate, hydroxypropyl (meth)acrylate maleate, monohydroxybutyl (meth)acrylate tetrahydrophthalate, etc. The inclusion of monomers having acidic groups can accelerate the curing of the paint composition.

[0030] The proportion of monomers containing acid groups in acrylic polyols is preferably 0 to 10% by mass relative to 100% by mass of the total constituent units of the acrylic polyol. A lower proportion makes it easier to maintain the water resistance of the coating film.

[0031] In the method for producing acrylic polyols, known polymerization methods such as solution polymerization, suspension polymerization, bulk polymerization, and emulsion polymerization can be applied. As for the polymerization method, solution polymerization using a polymerization solvent is preferred from the viewpoint of productivity of the produced acrylic polyol and ease of use as a paint composition. This polymerization method can be carried out, for example, by supplying a polymerization solvent, monomers, and a radical polymerization initiator into a polymerization vessel and polymerizing them at a predetermined reaction temperature.

[0032] Examples of radical polymerization initiators used in radical polymerization include, but are not limited to, organic peroxides such as benzoyl peroxide and di-t-butyl peroxide; and azo compounds such as 2,2'-azobisbutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile). These radical polymerization initiators may be used individually or in combination of two or more. It is preferable to use the radical polymerization initiator in an amount of 0.01 to 5% by mass relative to 100% by mass of the total constituent units of the acrylic polyol.

[0033] Furthermore, during radical polymerization, chain transfer agents can be used to control the weight-average molecular weight of the (meth)acrylic resin. Examples of chain transfer agents include butanethiol, octanthiol, decanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, cyclohexyl mercaptan, thiophenol, octyl thioglycolate, octyl 2-mercaptopropionate, octyl 3-mercaptopropionate, 2-ethylhexyl mercaptopropionate, 2-ethylhexyl thioglycolate, butyl-3-mercaptopropionate, mercaptopropyltrimethoxysilane, methyl-3-mercaptopropionate, and 2,2-(ethylenedi Examples of thiol compounds include oxy)diethanethiol, ethanethiol, 4-methylbenzenethiol, 2-mercaptoethyl octanoate, 1,8-dimercapto-3,6-dioxaoctane, decantrithiol, dodecyl mercaptan, diphenyl sulfoxide, dibenzyl sulfide, 2,3-dimethylcapto-1-propanol, mercaptoethanol, thiosalicylic acid, thioglycerol, thioglycolic acid, 3-mercaptopropionic acid, thiomalic acid, mercaptoacetic acid, mercaptosuccal acid, and 2-mercaptoethanesulfonic acid. These may be used individually or in combination of two or more.

[0034] The amount of chain transfer agent used is preferably 0.1 to 25% by mass, more preferably 0.5 to 20% by mass, and even more preferably 1.0 to 15% by mass, based on 100% by mass of the total constituent units of the acrylic polyol.

[0035] Examples of polymerization solvents that can be used in solution polymerization include the following solvents. Aromatic solvents such as toluene, xylene, and other high-boiling aromatic solvents; ester solvents such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and cellosolve acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cycloheptanone, and cyclohexanone; alcohol solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, propylene glycol monomethyl ether, and diacetone alcohol; hydrocarbon solvents such as SS-100 (manufactured by JXTG Energy Corporation, product name) and cyclohexane. Polymerization solvents may be used individually or in combination of two or more types. In particular, solvents other than alcohol-based solvents, excluding tertiary alcohols, are preferred in order to prevent unintended reactions with polyisocyanate (B).

[0036] <Polyester Polyol> Polyester polyols are polycondensates of an acidic component mainly composed of polyhydric carboxylic acids and an alcoholic component mainly composed of polyhydric alcohols.

[0037] Acidic components include terephthalic acid, isophthalic acid, phthalic acid or its anhydride, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, etc. Aromatic dicarboxylic acids and their anhydrides; aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. Furthermore, lactones such as γ-butyrolactone and ε-caprolactone; and their corresponding hydroxycarboxylic acids, as well as aromatic oxymonocarboxylic acids such as p-oxyethoxybenzoic acid; and polycarboxylic acids with three or more valencies such as trimellitic acid, trimezic acid, and pyromellitic acid may be included.

[0038] The alcohol components include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,5-hexanediol, diethylene glycol, triethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A alkylene oxide adduct, bisphenol S alkylene oxide adduct, as well as aliphatic glycols with side chains such as 1,2-propanediol, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 1,2-pentanediol, 2,3-pentanediol, 1,4-pentanediol, 1,4-hexanediol, 2,5-hexanediol, 3-methyl-1,5-pentanediol, 1,2-dodecanediol, and 1,2-octadecanediol. The alcohol components may also include trivalent or higher polyhydric alcohols such as trimethylolpropane, glycerin, and pentaerythritol.

[0039] <Polyisocyanate (B)> In the present invention, the polyisocyanate (B) reacts with the hydroxyl groups of the polyol (A) to form urethane bonds, increasing the crosslinking density of the cured film and improving weather resistance, chemical resistance, and hardness of the cured film.

[0040] Examples of the polyisocyanate (B) include bifunctional isocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, and 4,4-dicyclohexyl diisocyanate, as well as trifunctional or more isocyanates synthesized from the above bifunctional isocyanates as starting materials, such as biuret compounds, trimethylolpropane adduct compounds, isocyanurate compounds, and allophanate compounds.

[0041] Examples of isocyanates with three or more functions include: hexamethylene diisocyanate burette (product name: Duranate (registered trademark; hereinafter the same) 24A-100), hexamethylene diisocyanate adduct (product name: Duranate P-301-75E), hexamethylene diisocyanate isocyanurate (product name: Duranate TPA-100), polyfunctional isocyanate (product name: Duranate MHG-80B), block-type isocyanate (product name: Duranate MF-K60X), and 1,3-bis(isocyanatomethyl)cyclohexane trimethylol manufactured by Mitsui Chemicals, Inc. Examples include propane adduct compounds (product name: Takenate (registered trademark; hereinafter the same) D-120N), isocyanurate compound of 1,3-bis(isocyanatomethyl)cyclohexane (product name: Takenate D-127N), trimethylolpropane adduct compound of isophorone diisocyanate (product name: Takenate D-140N), allophanate compound of hexamethylene diisocyanate manufactured by Sumika Covestro Urethane Co., Ltd. (product name: Desmodule (registered trademark; hereinafter the same) XP2679), and isocyanurate compound of isophorone diisocyanate manufactured by EVONIK (product name: Desmodule T-1890 / 100).

[0042] As the polyisocyanate (B), a trifunctional or more isocyanate is preferred in that it increases the crosslinking density of the cured film and improves weather resistance, stain resistance, and hardness of the cured film. The polyisocyanate (B) may be used alone or in combination of two or more types.

[0043] The mixing ratio of the polyisocyanate (B) and polyol (A) is preferably such that, from the viewpoint of the performance of the cured film, the NCO / OH [number of moles of isocyanate groups in polyisocyanate (B) / number of moles of hydroxyl groups in polyol (A)] is 0.5 or more and 2.0 or less, more preferably 0.7 or more and 1.8 or less, and even more preferably 0.8 or more and 1.5 or less.

[0044] If the equivalent ratio of isocyanate groups in the polyisocyanate (B) is equal to or greater than the lower limit, the curing speed of the resin composition can be increased, and the crosslinking density of the cured film of the resin composition can be increased, which tends to improve the hardness and water resistance of the cured film. If the equivalent ratio of isocyanate groups in the polyisocyanate (B) is equal to or less than the upper limit, the drying properties and adhesion after the cured film of the resin composition is formed tend to improve.

[0045] <Inorganic fine particles (C)> The inorganic fine particles (C) in the present invention have a functional group on its surface that can react with a hydroxyl group or an isocyanate group.

[0046] Since the inorganic fine particles (C) have functional groups on their surface that can react with hydroxyl groups or isocyanate groups, the inorganic fine particles (C) are immobilized on the resin component, thereby improving the abrasion resistance of the cured film.

[0047] Functional groups that can react with hydroxyl groups include isocyanate groups, epoxy groups, and carboxyl groups. Furthermore, functional groups that can react with isocyanate groups include mercapto groups, hydroxyl groups, amino groups, carboxyl groups, and isocyanate groups.

[0048] Due to their high reactivity with hydroxyl groups or isocyanate groups, mercapto groups, isocyanate groups, amino groups, and epoxy groups are preferred as functional groups that can react with hydroxyl groups or isocyanate groups of inorganic fine particles (C).

[0049] The inorganic fine particles (C) can be obtained, for example, by surface-treating silica particles that do not have a functional group that can react with a hydroxyl group or an isocyanate group on their surface with a silane coupling agent that has a functional group that can react with a hydroxyl group or an isocyanate group.

[0050] As silica particles that do not have functional groups on their surface that can react with hydroxyl groups or isocyanate groups, commercially available products such as methanol-dispersed silica sols (MA-ST, MA-ST-M), isopropyl alcohol-dispersed silica sols (IPA-ST, IPA-ST-L, IPA-ST-ZL, IPA-ST-UP), ethylene glycol-dispersed silica sols (EG-ST, EG-ST-L), dimethylacetamide-dispersed silica sols (DMAC-ST, DMAC-ST-L), xylene / butanol-dispersed silica sols (XBA-ST), methyl ethyl ketone-dispersed silica sols (MEK-ST, MEK-ST-L, MEK-ST-ZL, MEK-ST-UP), methyl isobutyl ketone-dispersed silica sols (MIBK-ST), and propylene glycol monomethyl ether acetate-dispersed silica sols (PMA-ST) manufactured by Nissan Chemical Corporation can be used.

[0051] Silane coupling agents having a functional group that can react with a hydroxyl group or an isocyanate group include, for example, silane compounds having a glycidyl group such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 1-mercaptomethyltrimethoxysilane, 1-mercaptomethylmethyldimethoxysilane, 1-mercaptomethyltriethoxysilane, 1-mercaptomethylmethyldiethoxysilane Examples include silane compounds having a mercapto group such as toxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldiethoxysilane; silane compounds having an amino group such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane; and 3-isocyanatetopropyltriethoxysilane.

[0052] Furthermore, commercially available dispersions of the inorganic fine particles (C) include, for example, MEK-EC-2130Y, MEK-EC-6150P, MEK-EC-7150P, and others manufactured by Nissan Chemical Corporation. The inorganic fine particles (C) may be used alone or in combination of two or more types.

[0053] The content of the inorganic fine particles (C) in the resin composition of the present invention is preferably 5 parts by weight or more and 100 parts by weight or less, more preferably 10 parts by weight or more and 50 parts by weight or less, and even more preferably 15 parts by weight or more and 40 parts by weight or less, per 100 parts by weight of polyol (A).

[0054] If the content of the inorganic fine particles (C) is below the upper limit, it is easier to maintain a high appearance over a long period of time and to reduce the cost of the paint. If the content of the inorganic fine particles (C) is above the lower limit, the scratch resistance and hardness of the resulting cured film are likely to improve.

[0055] The average particle size of the inorganic fine particles (C) is preferably 2 nm to 300 nm, more preferably 2 nm to 200 nm, even more preferably 4 nm to 100 nm, and particularly preferably 4 nm to 50 nm. If the average particle size of the inorganic fine particles (C) is greater than or equal to the lower limit, scratch resistance is likely to improve. If the average particle size of the inorganic fine particles (C) is less than or equal to the upper limit, the transparency of the cured film of the resin composition is likely to be maintained.

[0056] The average particle size of the inorganic fine particles (C) is calculated from the specific surface area measured by the BET adsorption method (in accordance with JIS-Z8830).

[0057] <Polycarbonate polyol (D)> The urethane resin composition of the present invention may contain a polycarbonate polyol (D) in addition to the polyol (A). The polycarbonate polyol may have a polycarbonate structure in its molecule and two or more hydroxyl groups at its ends, but it is preferable that the ends are primary hydroxyl groups. From the viewpoint of weather resistance, an aliphatic polycarbonate polyol is preferred as the polycarbonate polyol.

[0058] The aliphatic polycarbonate polyols include Kuraray Polyol (registered trademark; hereinafter the same) C-1090 (hydroxyl value 112 mg·KOH / g, weight-average molecular weight (Mw) 1000 (catalog value)), Kuraray Polyol C-2090 (hydroxyl value 56.1 mg·KOH / g, weight-average molecular weight (Mw) 2000 (catalog value)), Kuraray Polyol C-3090 (hydroxyl value 37 mg·KOH / g, weight-average molecular weight (Mw) 3000 (catalog value)), and Duranol (registered trademark; hereinafter the same) T-5651 (hydroxyl value 112 mg·KOH / g, weight-average molecular weight (Mw) 1000 (catalog value)), Duranol T-5652 (hydroxyl value 56 mgKOH / g, weight-average molecular weight (Mw) 2000 (catalog value)), and Duranol Duranol T-4691 (hydroxyl value 112 mg·KOH / g, weight-average molecular weight (Mw) 1000 (catalog value)), Duranol T-4692 (hydroxyl value 56 mg·KOH / g, weight-average molecular weight (Mw) 2000 (catalog value)), Duranol T-4671 (hydroxyl value 112 mg·KOH / g, weight-average molecular weight (Mw) 1000 (catalog value)), Duranol G-467 2 (Hydroxyl value 56 mg·KOH / g, weight-average molecular weight (Mw) 2000 (catalog value)), Duranol G-3450J (Hydroxyl value 140 mg·KOH / g, weight-average molecular weight (Mw) 800 (catalog value)), Duranol G-3452 (Hydroxyl value 56 mg·KOH / g, weight-average molecular weight (Mw) 2000 (catalog value)), Beneviol (registered trademark) manufactured by Mitsubishi Chemical Corporation.(The following are the same) NL1010DB (Hydroxyl value 112 mg·KOH / g, weight-average molecular weight (Mw) 1000 (catalog value)), Beneviol NL2010DB (Hydroxyl value 56 mg·KOH / g, weight-average molecular weight (Mw) 2000 (catalog value)), Beneviol NL1000B (Hydroxyl value 112 mg·KOH / g, weight-average molecular weight (Mw) 1000 (catalog value)), Beneviol NL2000B (Hydroxyl value 56 mg·KOH / g, weight-average molecular weight (Mw) 2000 (catalog value)), Beneviol NL1050B (Hydroxyl value 112 mg·KOH / g, weight-average molecular weight (Mw) 100 0 (catalog value), Beneviol NL2050B (hydroxyl value 56 mg·KOH / g, weight-average molecular weight (Mw) 2000 (catalog value)), Beneviol HS0840B (hydroxyl value 140 mg·KOH / g, weight-average molecular weight (Mw) 800 (catalog value)), Beneviol HS0850B (hydroxyl value 140 mg·KOH / g, weight-average molecular weight (Mw) 800 (catalog value)), ETERNALCOLL (registered trademark; same applies hereafter) UHC50-100 (hydroxyl value 112 mg·KOH / g, weight-average molecular weight (Mw) 1000 (catalog value)), ETERNALCOLL Examples include UHC50-200 (hydroxyl value 56 mg·KOH / g, weight-average molecular weight (Mw) 2000 (catalog value)), ETERNALCOLL UC-100 (hydroxyl value 112 mg·KOH / g, weight-average molecular weight (Mw) 1000 (catalog value)), and ETERNALCOLL UM-90 (hydroxyl value 125 mg·KOH / g, weight-average molecular weight (Mw) 900 (catalog value)).

[0059] The content of the polycarbonate polyol (D) in the resin composition of the present invention is preferably 1 part by weight or more and 100 parts by weight or less, more preferably 10 parts by weight or more and 70 parts by weight or less, and even more preferably 25 parts by weight or more and 50 parts by weight or less, per 100 parts by weight of polyol (A).

[0060] If the content of the polycarbonate polyol (D) is below the upper limit, compatibility with inorganic fine particles (C) is good, and the appearance of the coating film is good. If the content of the polycarbonate polyol (D) is above the lower limit, adhesion to the substrate is improved.

[0061] <UV absorber (E)> To improve the weather resistance of the cured product, an ultraviolet absorber (E) can be added to the urethane resin composition. From the viewpoint of heat resistance, an ultraviolet absorber with a molecular weight of 500 or more is preferred. From the viewpoint of good solubility in the composition and improvement of weather resistance, an ultraviolet absorber derived from triazine, benzotriazole, cyclic iminoester, benzophenone, salicylic acid ester, or cyanoacrylate compounds is preferred, and its maximum absorption wavelength is in the range of 240 to 380 nm.

[0062] Triazine-based UV absorbers are not limited to those listed below, but for example, 2-[4-([2-hydroxy-3-dodecyloxypropyl]oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-([2-hydroxy-3-tridecyloxypropyl]oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine (Tinuvin® 400 (Manufactured by BASF), 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-[3-(dodecyloxy)-2-hydroxypropoxy]phenol), reaction product of 2-(2,4-dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine and (2-ethylhexyl)-glycidic acid ester (Tinuvin® 405, manufactured by BASF), 2,4-bis"2-hydroxy-4- Examples include butoxyphenyl-6-(2,4-dibutoxyphenyl)-1,3-5-triazine (Tinuvin® 460, manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]-phenol (Tinuvin® 1577, manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]-phenol (ADK STAB LA46, manufactured by ADEKA), and 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine (Tinuvin® 479, manufactured by BASF).

[0063] Benzotriazole-based UV absorbers are not limited to those listed below, but include, for example, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-(2-hydroxy-5-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-butylphenyl)benzotriazole, and 2-(2-hydroxy-5-tert-butylphenyl). Xy-4-octyloxyphenyl)benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxymethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxypropyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyhexyl)phenyl]-2H-benzotriazole, 2-[2'- Hydroxy-3'-tert-butyl-5'-(methacryloyloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-tert-butyl-3'-(methacryloyloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-chloro-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-methoxy-2H-benzotriazole, 2-[ Examples include 2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-cyano-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-tert-butyl-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-5-nitro-2H-benzotriazole, and as a bisbenzotriazole-based UV absorber, Dainsorb® T-33 (manufactured by Yamato Kasei Co., Ltd.).

[0064] Examples of cyclic iminoester UV absorbers include, but are not limited to, 2-methyl-3,1-benzoxazin-4-one, 2-butyl-3,1-benzoxazin-4-one, 2-phenyl-3,1-benzoxazin-4-one, 2-(1- or 2-naphthyl)-3,1-benzoxazin-4-one, 2-(4-biphenyl)-3,1-benzoxazin-4-one, 2-p-nitrophenyl-3,1-benzoxazin-4-one, 2-m-nitrophenyl-3,1-benzoxazin-4-one, and 2-p-benzobutyl Phenyl-3,1-benzoxazin-4-one, 2-p-methoxyphenyl-3,1-benzoxazin-4-one, 2-o-methoxyphenyl-3,1-benzoxazin-4-one, 2-cyclohexyl-3,1-benzoxazin-4-one, 2-p-(or m-)phthalimidophenyl-3,1-benzoxazin-4-one, N-phenyl-4-(3,1-benzoxazin-4-one-2-yl)phthalimido, N-benzoyl-4-(3,1-benzoxazin-4-one-2-yl)aniline, N-benzoyl-N-methyl-4-( 3,1-Benzoxazine-4-one-2-yl)aniline, 2-(p-(N-methylcarbonyl)phenyl)-3,1-benzoxazine-4-one, 2,2'-bis(3,1-benzoxazine-4-one), 2,2'-ethylenebis(3,1-benzoxazine-4-one), 2,2'-tetramethylenebis(3,1-benzoxazine-4-one), 2,2'-decamethylenebis(3,1-benzoxazine-4-one), 2,2'-p-phenylenebis(3,1-benzoxazine-4-one), 2,2'-m-phenylenebis(3,1-be 3,1-benzoxazine-4-one), 2,2'-(4,4'-diphenylene)bis(3,1-benzoxazine-4-one), 2,2'-(2,6-or 1,5-naphthylene)bis(3,1-benzoxazine-4-one), 2,2'-(2-methyl-p-phenylene)bis(3,1-benzoxazine-4-one), 2,2'-(2-nitro-p-phenylene)bis(3,1-benzoxazine-4-one), 2,2'-(2-chloro-p-phenylene)bis(3,1-benzoxazine-4-one), 2,2'-(1,4-cyclohexylene)bis(3,1-Benzoxazine-4-one), 1,3,5-tri(3,1-benzoxazine-4-one-2-yl)benzene, 1,3,5-tri(3,1-benzoxazine-4-one-2-yl)naphthalene, 2,4,6-tri(3,1-benzoxazine-4-one-2-yl)naphthalene, 2,8-dimethyl-4H,6H-benzo(1,2-d;5,4-d')bis(1,3)-oxazine-4,6-dione, 2,7-dimethyl-4H,9H-benzo(1,2-d;4,5-d')bis(1,3)-oxazine-4,9-dione, 2,8-diphenyl Lu-4H,8H-benzo(1,2-d;5,4-d')bis(1,3)-oxazin-4,6-dione, 2,7-diphenyl-4H,9H-benzo(1,2-d;4,5-d')bis(1,3)-oxazin-4,6-dione, 6,6'-bis(2-methyl-4H,3,1-benzoxazin-4-one), 6,6'-bis(2-ethyl-4H,3,1-benzoxazin-4-one), 6,6'-bis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,6'-methylenebis(2-methyl-4H,3,1-benzoxazin-4- 6,6'-methylenebis(2-phenyl-4H,3,1-benzoxazine-4-one), 6,6'-ethylenebis(2-methyl-4H,3,1-benzoxazine-4-one), 6,6'-ethylenebis(2-phenyl-4H,3,1-benzoxazine-4-one), 6,6'-butylenebis(2-methyl-4H,3,1-benzoxazine-4-one), 6,6'-butylenebis(2-phenyl-4H,3,1-benzoxazine-4-one), 6,6'-oxybis(2-methyl-4H,3,1-benzoxazine-4-one), 6 ,6'-Oxybis(2-phenyl-4H,3,1-benzoxazine-4-one), 6,6'-Sulfonylbis(2-methyl-4H,3,1-benzoxazine-4-one), 6,6'-Sulfonylbis(2-phenyl-4H,3,1-benzoxazine-4-one), 6,6'-Carbonylbis(2-methyl-4H,3,1-benzoxazine-4-one), 6,6'-Carbonylbis(2-phenyl-4H,3,1-benzoxazine-4-one), 7,7'-Methylenebis(2-methyl-4H,3,1-benzoxazine-4-one), 7,7'-Methylenebis(2-phenyl-4H,3,1-benzoxazin-4-one), 7,7'-Bis(2-methyl-4H,3,1-benzoxazin-4-one), 7,7'-Ethylenebis(2-methyl-4H,3,1-benzoxazin-4-one), 7,7'-Oxybis(2-methyl-4H,3,1-benzoxazin-4-one), 7,7'-Sulfonylbis(2-methyl-4H,3,1-benzoxazin-4-one), 7,7 Examples include '-carbonylbis(2-methyl-4H,3,1-benzoxazine-4-one), 6,7'-bis(2-methyl-4H,3,1-benzoxazine-4-one), 6,7'-bis(2-phenyl-4H,3,1-benzoxazine-4-one), 6,7'-methylenebis(2-methyl-4H,3,1-benzoxazine-4-one), and 6,7'-methylenebis(2-phenyl-4H,3,1-benzoxazine-4-one).

[0065] Examples of benzophenone-based UV absorbers (benzophenone compounds) and oxybenzophenone-based UV absorbers (oxybenzophenone compounds) include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (anhydrous and trihydrate), 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone (trade name "KEMISORB111", manufactured by Chemipro Chemicals Co., Ltd.), 2,2',4,4'-tetrahydroxybenzophenone (trade name "SEESORB106", manufactured by Cipro Chemicals Co., Ltd.), and 2,2'-dihydroxy-4,4-dimethoxybenzophenone.

[0066] Examples of salicylic acid ester-based UV absorbers (salicylic acid ester compounds) include phenyl-2-acryloyloxybenzoate, phenyl-2-acryloyloxy-3-methylbenzoate, phenyl-2-acryloyloxy-4-methylbenzoate, phenyl-2-acryloyloxy-5-methylbenzoate, phenyl-2-acryloyloxy-3-methoxybenzoate, phenyl-2-hydroxybenzoate, phenyl-2-hydroxy-3-methylbenzoate, phenyl-2-hydroxy-4-methylbenzoate, phenyl-2-hydroxy-5-methylbenzoate, phenyl-2-hydroxy-3-methoxybenzoate, and 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate (Tinuvin® 120, manufactured by BASF).

[0067] Examples of cyanoacrylate-based ultraviolet absorbers (cyanoacrylate compounds) include alkyl-2-cyanoacrylate, cycloalkyl-2-cyanoacrylate, alkoxyalkyl-2-cyanoacrylate, alkenyl-2-cyanoacrylate, and alkynyl-2-cyanoacrylate. Furthermore, these compounds may be used individually or in combination of two or more.

[0068] Among these, triazine-based and benzotriazole-based materials are more preferred, with triazine-based materials being even more preferred, in terms of particularly good UV absorption and excellent appearance when used as a hard coat layer. Furthermore, UV absorbers having non-phenolic hydroxyl groups are preferred, particularly 2-[4-([2-hydroxy-3-dodecyloxypropyl]oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-([2-hydroxy-3-tridecyloxypropyl]oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine (Tinuvin® 400) Preferred are 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl]-5-[3-(dodecyloxy)-2-hydroxypropoxy]phenol (manufactured by BASF), the reaction product of 2-(2,4-dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine and (2-ethylhexyl)-glycidic acid ester (Tinuvin® 405, manufactured by BASF), polypropylene glycol ester of 3-[2-(2-hydroxy-5-tert-butylphenyl)-benzotriazole]-propionic acid (Tinuvin® 1130, manufactured by BASF), and Dynesorb® T-33 (manufactured by Yamato Kasei Co., Ltd.).

[0069] The content of the ultraviolet absorber (E) in the urethane resin composition is preferably 20% by mass or less, more preferably 0.01 to 15% by mass, even more preferably 0.1 to 10% by mass, particularly preferably 0.5 to 8% by mass, and most preferably 1 to 5% by mass, relative to the non-volatile content. If the content of the ultraviolet absorber is above the lower limit, the weather resistance of the cured film tends to improve. If the content of the ultraviolet absorber is below the upper limit, the curability of the paint composition, the toughness of the cured film, the heat resistance, and the scratch resistance tend to improve.

[0070] <Light stabilizer (F)> To further improve the weather resistance of the cured product, a light stabilizer (F) can be added to the urethane resin composition. The light stabilizer (F) is not particularly limited as long as it is a hindered amine-based light stabilizer. Specific examples of light stabilizers (F) include bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1-methoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1-ethoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1-propoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, and bis(1-butoxy-2,2,6,6-tetramethyl (Tyl-4-piperidyl) sebacate, bis(1-pentyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1-hexyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1-heptyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1-nonyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis( 1-Decanyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1-dodecyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-2-(4-methoxy-benzylidene) malonate, tetrakis(2,2,6,6-pentamethyl-4-piperidyl)1,2,3,4-butanetetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)1,2,3,4-butanetetracarboxylate Aminomethyl group-containing compounds such as tantetracarboxylate, condensates of 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol, and β,β,β,β-tetramethyl-3,9-(2,4,8,10-tetraoxaspiro[5,5])undecane)diethanol, 1,2,3,4-butanetetracarboxylic acid, 2,2,6,6-pentamethyl-4-piperidinol, and β,β,β,β-tetramethyl-3,9-(2,4,8,10-tetraoxaspiro[5,Examples of amino ether group-containing compounds include the condensate with undecane diethanol, the reaction product of a diester compound of decanedicarboxylic acid and 2,2,6,6-tetramethyl-1-octoxy-4-piperidinol with 1,1-dimethylethyl hydroperoxide and octane (BASF, trade name Tinuvin 123), and bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-[[3,5-bis(1,1,dimethylethyl)-4-hydroxyphenyl]methyl] (BASF, trade name Tinuvin 144). Among these, amino ether group-containing compounds are preferred from the viewpoint of weather resistance of the cured product, and bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-[[3,5-bis(1,1,dimethylethyl)-4-hydroxyphenyl]methyl] is particularly preferred. Furthermore, these compounds may be used individually or in combination of two or more.

[0071] The content of the light stabilizer (F) in the urethane resin composition is preferably 20% by mass or less, more preferably 0.01 to 15% by mass, even more preferably 0.1 to 10% by mass, particularly preferably 0.5 to 8% by mass, and most preferably 1 to 5% by mass, relative to the non-volatile content. Using this range allows for effective formation of a cured film and improves the weather resistance of the cured film.

[0072] <Leveling agent> To improve the appearance of the cured product, a leveling agent can be added to the urethane resin composition. Examples of leveling agents include acrylic leveling agents, silicone leveling agents, and fluorine leveling agents. Among these, silicone leveling agents are more preferable from the viewpoint of improving abrasion resistance, which is one of the issues addressed in this invention. Furthermore, silicone leveling agents having hydroxyl groups are particularly preferable because they also prevent the leveling agent from bleeding out even after weathering degradation. Silicone leveling agents impart slipperiness to the cured product, achieving high scratch resistance. Silicone leveling agents having hydroxyl groups are incorporated into the cured product by reacting with the isocyanate groups of polyisocyanate (B) contained in the urethane resin composition, and are very useful because they can achieve slipperiness and scratch resistance over a long period of time.

[0073] The leveling agent content in the urethane resin composition is preferably 20% by mass or less, more preferably 0.01 to 10% by mass, even more preferably 0.1 to 5% by mass, particularly preferably 0.2 to 4% by mass, and most preferably 0.3 to 3% by mass, relative to the non-volatile content. Using this range not only improves the appearance of the cured film but also improves its abrasion resistance.

[0074] The urethane resin composition may further contain various additives as needed, such as organic solvents, antioxidants, anti-yellowing agents, bluing agents, pigments, dyes, defoamers, thickeners, anti-settling agents, antistatic agents, and anti-fogging agents.

[0075] <Curing accelerating catalyst> The resin composition of the present invention can be cured at room temperature or by heating, but may optionally contain a curing accelerator.

[0076] While not particularly limited, commonly used metal catalysts such as monoamines like triethylamine and N,N-dimethylcyclohexylamine, diamines like tetramethylethylenediamine, other triamines, cyclic amines, alcohol amines like dimethylethanolamine, ether amines, potassium acetate, potassium 2-ethylhexanoate, calcium acetate, lead octyolate, dibutyltin dilaurate, tin octyolate, bismuth neodecanoate, bismuth oxycarbonate, bismuth 2-ethylhexanoate, zinc octyolate, zinc neodecanoate, phosphine, and phosphophosphate can be used as curing accelerators. These can be used individually or in combination of two or more.

[0077] The content of the curing accelerator catalyst is preferably 0.001% to 10% by mass, more preferably 0.01% to 5% by mass, and even more preferably 0.1% to 1% by mass, relative to the mass (100% by mass) of polyisocyanate (B).

[0078] <Organic solvents> The urethane resin composition of the present invention preferably contains 1% to 90% by mass of an organic solvent based on the weight (100% by mass) of the composition in order to adjust the workability during painting. More preferably, the organic solvent content is 20% to 80% by mass, and even more preferably 40% to 70% by mass.

[0079] The organic solvents used are not particularly limited, but examples include alcohols such as methanol, ethanol, isopropyl alcohol, n-butanol, diacetone alcohol, 2-methoxyethanol (methyl cellosolve), 2-ethoxyethanol (ethyl cellosolve), 2-butoxyethanol (butyl cellosolve), and tert-amyl alcohol; esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, and butyl formate; ketones such as methyl ethyl ketone, methyl isobutyl ketone, acetone, cyclohexanone, and diisobutyl ketone; amides such as dimethylformamide and dimethylacetamide; ethers such as diethyl ether, methoxytoluene, 1,2-dimethoxyethane, 1,2-dibutoxyethane, 1,1-dimethoxymethane, 1,1-dimethoxyethane, 1,4-dioxane, and tetrahydrofuran; aliphatic hydrocarbons such as pentane, hexane, heptane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbons such as toluene, xylene, and benzene.

[0080] In particular, solvents other than primary and secondary alcohols are preferred because they do not react with polyisocyanate (B) and do not degrade the physical properties of the cured film. These may be used individually or in combination of two or more.

[0081] <Base material> Examples of base materials include metals such as galvanized steel sheets, zinc alloy plated steel sheets, stainless steel sheets, and tin-plated steel sheets, as well as polymethyl methacrylate resin, polycarbonate resin, polyester resin, polystyrene resin, ABS resin, AS resin, polyamide resin, polyarylate resin, polymethacrylimide resin, and polyaryl diglycol carbonate resin.

[0082] Among these, polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, and polymethacrylimide resin are particularly preferred from the viewpoint of improving the abrasion resistance of the cured surface.

[0083] <Cured product> The coating composition of the present invention can be applied to a substrate by known methods such as brush coating, bar coating, spray coating, dip coating, spin coating, and curtain coating.

[0084] The curing temperature when curing the coating composition of the present invention applied to a substrate can be set appropriately considering the heat resistance and thermal deformation properties of the substrate, but is preferably 20°C to 200°C, more preferably 60°C to 150°C, and even more preferably 80°C to 120°C.

[0085] The curing time for the coating composition of the present invention applied to a substrate is preferably 5 to 120 minutes, more preferably 8 to 30 minutes, and even more preferably 10 to 20 minutes. A shorter curing time allows for a shorter manufacturing time, while a longer curing time improves scratch resistance.

[0086] <Laminate> In the laminate of the present invention, the thickness of the cured film of the resin composition of the present invention is preferably 3 μm or more and 50 μm or less.

[0087] If the thickness of the cured film in the laminate of the present invention is greater than or equal to the lower limit, the scratch resistance and weather resistance of the cured film will be good, and it will be easier to maintain a high appearance for a long period of time. If the thickness of the cured film in the laminate of the present invention is less than or equal to the upper limit, it will be easier to suppress cracks.

[0088] Regarding the scratch resistance of the cured product, the change in haze in the scratch test described later is preferably 5.0% or less, more preferably 3.0% or less, even more preferably 2.6% or less, particularly preferably 2.0% or less, and most preferably 1.9% or less, with a lower limit of 0.0%. By keeping it within this range, it is possible to prevent scratches on the laminate.

[0089] In the tests described later, the hardness of the cured material is preferably HB or higher on the pencil hardness scale, and more preferably F or higher. This range helps prevent scratching of the laminate.

[0090] In terms of the liquid stability of the paint composition, it is preferable that no precipitates form for one month in the tests described later, and more preferably that no precipitates form for one month or more. Meeting this range allows for use in high-temperature environments.

[0091] <Application> The urethane resin composition of the present invention has excellent appearance, scratch resistance, weather resistance, and hardness, and can therefore be suitably used in applications such as various lamp lenses for automobiles, plastic exterior components, and glazing hard coats. [Examples]

[0092] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. The various manufacturing conditions and evaluation result values ​​in the following examples are intended to represent preferred upper or lower limits in embodiments of the present invention, and the preferred range may be defined by a combination of the aforementioned upper or lower limits and the values ​​of the following examples or the values ​​of the examples themselves. Note that unless otherwise specified, "parts" and "%" refer to "parts by mass" and "% by mass," respectively. The measurement and evaluation methods used in this invention are as follows.

[0093] [Measurement and evaluation methods] <Weight average molecular weight> The weight-average molecular weight (Mw) was measured by gel permeation chromatography (GPC) under the following conditions and calculated on a standard polystyrene basis. Equipment: Tosoh Corporation high-speed GPC system HLC-8320GPC model UV detector: Tosoh Corporation UV-8320 model Flow rate: 0.35mL / min Inlet temperature: 40℃ Oven temperature: 40℃ RI temperature: 40℃ UV wavelength: 254nm Sample injection volume: 10 μL Columns: Three columns linked together in the order of (1) to (3). (1) TSKgel superHZM-M (4.6mm ID x 15cm L) manufactured by Tosoh Corporation (2) TSKgel superHZM-M (4.6mm ID x 15cm L) manufactured by Tosoh Corporation (3) TSKgel HZ2000 manufactured by Tosoh Corporation (4.6mm ID x 15cm L) Guard column: TSKguardcolumn SuperHZ-L (4.6mm ID x 3.5cm L) manufactured by Tosoh Corporation Solvent: THF (stabilizer BHT) Sample concentration: Adjusted to 0.2% by mass of resin content

[0094] <Evaluation Sample> Each of the coating compositions listed in Tables 2-4 was spray-coated onto a 3mm thick polycarbonate resin sheet (manufactured by Mitsubishi Engineering Plastics, product name: "IUPILON ML-300") so that the cured film thickness was 10μm. The coating was then formed on the polycarbonate resin sheet by heat treatment under the conditions listed in Tables 5-7 and evaluated.

[0095] <Appearance of the coating film> The appearance of the coating film was evaluated by measuring the diffuse transmittance (haze value) using a haze meter (HM-65W, manufactured by Murakami Color Technology Research Institute Co., Ltd.) in accordance with JIS K7136:2000. Good: Less than 1% Defective: 1% or more

[0096] <Adhesion> The adhesion of the coating film was evaluated using the following procedure. Eleven scratches reaching the substrate were made on the surface of the coating film with a cutter at 1.5 mm intervals in both the vertical and horizontal directions, creating 100 grids. Cellophane adhesive tape (25 mm wide, manufactured by Nichiban Co., Ltd.) was pressed onto the grids and then rapidly peeled off upwards. Adhesion was evaluated based on the following criteria: number of remaining grids / total number of grids (100) and visual observation. No peeling: 100 / 100 Delamination present: 0 / 100 to 99 / 100.

[0097] <Scratch resistance> The scratch resistance of the coating film was evaluated using a flat abrasion tester (KASAI scratch tester). Steel wool #000 was placed on the evaluation sample and subjected to 50 back-and-forth abrasions under a load of 250g / 1.1cm2. After that, the diffuse transmittance (haze value) was measured using a haze meter (HM-65W, Murakami Color Technology Research Institute Co., Ltd.). Scratch resistance was determined by subtracting the initial haze value from the measured haze value (Δhaze value).

[0098] <Pencil hardness> The hardness of the coating film was evaluated using the pencil hardness scale in accordance with ISO / DIS 15184. After testing, the highest hardness among those that remained completely scratch-free was adopted as the pencil hardness of the coating film.

[0099] <Liquid storage stability> The paint compositions shown in Table 1 were mixed, and their appearance was visually observed and evaluated. 〇:Transparent ×: Cloudy, sediment present

[0100] <Liquid storage stability> The paint compositions shown in Table 1, excluding polyisocyanate (B), were mixed, sealed, and stored in a 60°C warm bath. The liquid's appearance was checked weekly, and the time until precipitates formed was used as the liquid's storage stability.

[0101] <Production of polyol (A)> • Manufacturing Example 1 (Polyol A-1) In a four-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet, 55.7 parts of propylene glycol monomethyl ether acetate were added as the initial solvent, and the mixture was heated under nitrogen gas aeration to an internal temperature of 140°C. After the internal temperature stabilized, a mixture of 60 parts 2-hydroxyethyl methacrylate, 15 parts n-butyl acrylate, 22 parts 2-ethylhexyl acrylate, 3 parts acrylic acid, and 6 parts of Perbutyl® O (tert-butyl peroxy 2-ethylhexanoate, manufactured by Nippon Oil & Fats Co., Ltd.) as a polymerization initiator (added dropwise) was added dropwise over 4 hours. After holding for 1 hour after the dropwise addition was complete, 0.3 parts of Perbutyl® O were dissolved in 15 parts of propylene glycol monomethyl ether acetate and added. After holding for another 1 hour, the mixture was cooled to room temperature to obtain polyol (A-1). The weight-average molecular weight (Mw), glass transition temperature (Tg), hydroxyl value (OHV), and SP value of the copolymer in polyol A-1 are shown in the copolymer properties column of Table 1.

[0102] • Manufacturing examples 2-7 (Polyol A-2-A-7) Polyols A-2 to A-7 with a solid content of 60% were obtained in the same manner as in Production Example 1, except that the monomers shown in Table 1 below were used in Production Example 1.

[0103] [Table 1]

[0104] <Manufacturing of resin (Z) without hydroxyl groups> • Manufacturing example 8 In a four-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet, 55.7 parts of propylene glycol monomethyl ether acetate were added as the initial solvent, and the mixture was heated under nitrogen gas aeration to an internal temperature of 140°C. After the internal temperature stabilized, a mixture of 100 parts of methyl methacrylate and 6 parts of perbutyl®O (tert-butyl peroxy 2-ethyl hexanoate, manufactured by Nippon Oil & Fats Co., Ltd.) as a polymerization initiator was added dropwise over 4 hours. After holding for 1 hour after the dropwise addition was complete, 0.3 parts of perbutyl®O were dissolved in 15 parts of propylene glycol monomethyl ether acetate and added. After holding for another 1 hour, the mixture was cooled to room temperature to obtain a resin (Z) without hydroxyl groups. The weight-average molecular weight (Mw) of the copolymer in resin (Z) was 6000, the glass transition temperature (Tg) was 95°C, and the SP value was 9.5.

[0105] <Manufacturing of inorganic fine particles (C)> • Manufacturing Example 9 (Dispersion of Inorganic Particles C-1) 1.2 g of 3-mercaptopropyltrimethoxysilane manufactured by Shin-Etsu Chemical Co., Ltd., 0.6 g of distilled water, and 2.1 g of tetrahydrofuran were added to flask A, and the mixture was stirred at 30°C for 3 hours to obtain a silanol solution. 100 g of methyl isobutyl ketone dispersed silica sol (product name: "MIBK-ST", solvent: methyl isobutyl ketone, solid content concentration: 30% by mass, average particle size: 15 nm) manufactured by Nissan Chemical Corporation was added to flask B, and the temperature was raised to 70°C. The silanol solution from flask A was added dropwise to flask B, and the mixture was stirred at 70°C for 1 hour after the addition was complete. The solvent of the resulting inorganic fine particle dispersion was dried at 100°C for 2 hours, and 65 g of acetonitrile was added to 35 g of the remainder and stirred to obtain acetonitrile dispersion C-1 (solid content 35%) of inorganic particles having mercapto groups.

[0106] • Manufacturing Example 10 (Dispersion of Inorganic Particles C-2) 1.2 g of 3-mercaptopropyltrimethoxysilane manufactured by Shin-Etsu Chemical Co., Ltd., 0.6 g of distilled water, and 2.1 g of tetrahydrofuran were added to flask A, and the mixture was stirred at 30°C for 3 hours to obtain a silanol solution. 100 g of methyl isobutyl ketone dispersed silica sol (product name: "MIBK-ST", solvent: methyl isobutyl ketone, solid content concentration: 30% by mass, average particle size: 15 nm) manufactured by Nissan Chemical Corporation was added to flask B, and the temperature was raised to 70°C. The silanol solution from flask A was added dropwise to flask B, and the mixture was stirred at 70°C for 1 hour after the addition was complete to obtain methyl isobutyl ketone dispersion C-2 (35% solids) of inorganic particles having mercapto groups.

[0107] [Example 1] 100 parts of polyol A-1 (60% resin content), 34 parts of inorganic fine particle dispersion C-1 (35% solid content), 25 parts of ethanacol UM-90 (1 / 1) (manufactured by Ube Industries, Ltd., Mw: 900) as polycarbonate polyol D-1, 7.5 parts of Chinuvin 405 (manufactured by BASF) and 2.5 parts of Chinuvin 479 (manufactured by BASF) as UV absorbers (E), 2.5 parts of Chinuvin 152 (manufactured by BASF) as light stabilizers (F), 0.02 parts of dibutyltin dilaurate (DBTDL) as a curing accelerator catalyst, 0.4 parts of BYK-370 (manufactured by BYK) as a surface modifier, and 300 parts of cyclohexanone as a solvent were used and uniformly mixed. Finally, 64.9 parts of Duranate TPA-100 (manufactured by Asahi Kasei Corporation) were added as polyisocyanate B-1 and stirred for 30 minutes. The evaluation results of the cured product of the obtained paint composition are shown in Table 3.

[0108] [Examples 2-17 and Comparative Examples 1-6] In Example 1, the paint composition was changed to one shown in Tables 2-4, but otherwise the product was manufactured in the same manner as in Example 1, and a cured product was obtained. The evaluation results of the obtained cured product are shown in Tables 5-7 below.

[0109] [Table 2]

[0110] [Table 3]

[0111] [Table 4]

[0112] [Table 5]

[0113] [Table 6]

[0114] [Table 7]

[0115] The ingredients listed in the table are as follows: · A-8: Basonol HPE 1170B (manufactured by BASF), a hyperbranched polyester polyol with hydroxyl groups at the terminals, solids content 70%, hydroxyl value: 280 mg·KOH / g, weight-average molecular weight (Mw): 1800. • C-3: MEK-EC-2130Y (manufactured by Nissan Chemical Corporation), MEK dispersion of colloidal silica with epoxy groups, solid content 30%, particle size 15 μm. MEK-ST (manufactured by Nissan Chemical Corporation), MEK-dispersed colloidal silica sol, non-reactive, solids content 40% D-1: UM-90 (1 / 1) (manufactured by Ube Industries, Ltd.) Polycarbonate diol, 100% solids content, hydroxyl value: 127 mg KOH / g, weight-average molecular weight (Mw): 900. • E-1: Tinuvin 405 (BASF), hydroxyphenyltriazine-based UV absorber, hydroxyl value: 96.5 mg KOH / g • E-2: Tinuvin 479 (BASF) Hydroxyphenyltriazine-based UV absorber F-1: Tinuvin 152 (manufactured by BASF) Hindered amine light stabilizer. · B-1: Duranate TPA-100 (manufactured by Asahi Kasei Corporation), nurate-type polyfunctional isocyanate, NCO value: 23.1%, solids content: 100%. · B-2: Duranate 24A-100 (manufactured by Asahi Kasei Corporation), biuret-type polyfunctional isocyanate, NCO value: 23.5%, solids content: 100%. · B-3: Duranate 301P-75 (manufactured by Asahi Kasei Corporation), adduct-type polyfunctional isocyanate, NCO value: 12.5%, solids content: 75%. KBM-803: 3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.). • BYK-370: Silicone-based leveling agent (manufactured by BYK) • DBTDL: Dibutyltin dilaurate, Solids content: 100% (Manufactured by Tokyo Chemical Industry Co., Ltd.)

[0116] The cured products obtained in Examples 1 to 17 all exhibited good scratch resistance, hardness, and adhesion, and also showed excellent liquid stability of the paint.

[0117] In Comparative Example 1, when A-8, which does not have hydroxyl groups, was used, a sufficient cross-linked structure could not be formed, resulting in low scratch resistance. In Comparative Examples 2 and 3, the absence of inorganic fine particles C resulted in insufficient scratch resistance in the cured products. In Comparative Example 4, the compatibility between polyol A and inorganic fine particles C-4 was poor, resulting in cloudy coating film, as well as poor scratch resistance and liquid storage stability. In Comparative Example 5, the compatibility between polyol A and inorganic fine particles C-4 was poor, resulting in a cloudy coating film, as well as poor scratch resistance and liquid storage stability. Comparative Example 6 did not contain polyisocyanate B, resulting in poor scratch resistance and adhesion.

Claims

1. A urethane resin composition comprising a polyol (A), a polyisocyanate (B), and inorganic fine particles (C), wherein the hydroxyl value of the polyol (A) is 20 to 300 mgKOH / g, the inorganic fine particles (C) have a functional group that can react with a hydroxyl group or an isocyanate group, and the proportion of the inorganic fine particles (C) is 5 to 100 parts by weight per 100 parts by weight of the polyol (A).

2. The urethane resin composition according to claim 1, wherein the inorganic fine particles (C) are colloidal silica modified with a silane coupling agent.

3. The urethane resin composition according to claim 1 or 2, wherein the reactive group of the inorganic fine particles (C) is any one of an isocyanate group, an epoxy group, or a mercapto group.

4. The urethane resin composition according to any one of claims 1 to 3, wherein the polyol (A) is either an acrylic polyol or a polyester polyol.

5. The urethane resin composition according to any one of claims 1 to 4, wherein the solubility parameter of the polyol (A) is 8.7 or more and 12.0 or less.

6. The urethane resin composition according to any one of claims 1 to 5, wherein the glass transition temperature of the polyol (A) is -40°C or higher and 100°C or lower.

7. The urethane resin composition according to any one of claims 1 to 6, wherein the weight-average molecular weight of the polyol (A) is 900 or more and less than 200,000.

8. The urethane resin composition according to any one of claims 1 to 7, comprising a polycarbonate polyol (D) in addition to the polyol (A).

9. The urethane resin composition according to any one of claims 1 to 8, wherein the urethane resin composition comprises an ultraviolet absorber (E).

10. The urethane resin composition according to any one of claims 1 to 9, wherein the ultraviolet absorber (E) is hydroxyphenyltriazine-based.

11. The urethane resin composition according to any one of claims 1 to 10, wherein the urethane resin composition comprises a hindered amine-based light stabilizer (F).

12. A paint composition comprising the urethane resin composition according to any one of claims 1 to 11.

13. A cured product obtained by curing the urethane resin composition according to any one of claims 1 to 11.

14. A cured product obtained by applying the urethane resin composition according to any one of claims 1 to 11 onto a polycarbonate resin substrate and drying it in a 120°C atmosphere for 30 minutes, wherein the film thickness of the cured product is 5 to 30 μm, and the scratch hardness conforming to JIS 5600-5-4 is HB or higher.

15. Laminate having a coating film made of the cured product according to claim 13 or 14

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