Coating composition, laminate, and decorative sheet

Abstract

The present invention pertains to an active energy ray-curable coating composition containing: a urethane (meth)acrylate resin (A); a (meth)acryloyl group-containing monomer (B) (excluding fluorine-based surfactants); and inorganic oxide particles (C). The urethane (meth)acrylate resin (A) contains a structure based on isophorone diisocyanate. The number of (meth)acryloyl groups contained in a molecule of the urethane (meth)acrylate resin (A) is 4 to 12, the weight average molecular weight of said resin is 5,000 to 80,000, and the urethane bond amount of the resin is 3.0 x 10-3 to 5.6 x 10-3 eq / g. The (meth)acryloyl group-containing monomer (B) contains a monofunctional monomer (B1) containing one (meth)acryloyl group per molecule and a polyfunctional monomer (B2) containing 3 to 10 (meth)acryloyl groups per molecule. The glass transition temperature of a homopolymer of the monofunctional monomer (B1) is 90 to 160°C. The mass ratio of the monofunctional monomer (B1) to the polyfunctional monomer (B2) in terms of solid content is 0.3 to 1.2. The average particle diameter of the inorganic oxide particles (C) is 90 nm or less. The content of the urethane (meth)acrylate resin (A) in terms of solid content is 65.0 to 85.0 mass% relative to the total mass of the solid content of the coating composition.

Description

Paint composition, laminate, and decorative sheet

[0001] The present invention relates to a coating composition, a laminate, and a decorative sheet. This application claims priority based on Japanese Patent Application No. 2024-200735, filed in Japan on November 18, 2024, and Japanese Patent Application No. 2025-136470, filed in Japan on August 19, 2025, the contents of which are incorporated herein by reference.

[0002] Conventionally, decorative sheets are sometimes placed on the surface of molded products such as building materials, electronic equipment casings, and automotive interior components for the purpose of decoration or surface protection. Plastic film is widely used as the base material for these decorative sheets. However, plastic film is easily scratched on its surface. Therefore, to protect the plastic film and the molded product being decorated, an ultraviolet-curable coating composition is sometimes applied to the plastic film and cured to form a cured coating film.

[0003] In applications such as these, cured coatings require excellent hardness to prevent scratches. Furthermore, with the increasing diversity of molded products in recent years, moldability such as flexibility and stretchability to be applied to various shapes is also sometimes required. However, while cured coatings formed from conventional UV-curing paint compositions have excellent hardness, they have poor moldability, leading to problems such as cracking during molding.

[0004] Generally, when a cured coating becomes harder, its hardness improves, but its moldability decreases. Conversely, when a cured coating becomes softer, its moldability improves, but its hardness decreases. Methods for improving hardness include incorporating polyfunctional compounds having multiple polymerizable functional groups into the coating composition, or incorporating inorganic oxide particles such as alumina or silica. Furthermore, in recent years, there has been a demand for not only weather resistance, where the cured coating formed from the coating composition does not undergo changes in appearance such as yellowing in the natural environment, but also weather-resistant adhesion, where the adhesion to the substrate does not decrease.

[0005] Patent Document 1 proposes an ultraviolet-curable resin composition comprising an acrylate monomer having a bifunctional or more fluorene skeleton, alumina fine particles, and an ultraviolet-curable resin. Patent Document 2 proposes an ultraviolet-curable resin composition comprising a urethane acrylate oligomer and alumina particles or silica particles. Patent Document 3 proposes an ultraviolet-curable coating composition comprising acrylic urethane and surface-modified colloidal silica.

[0006] Japanese Patent Publication No. 2013-082108, Japanese Patent Publication No. 2018-111793, Japanese Patent Publication No. 2004-124108

[0007] However, the UV-curable resin composition described in Patent Document 1 is intended for use as a hard coat layer and does not guarantee sufficient moldability, nor does it have sufficient weather-resistant adhesion. Patent Document 2 describes how moldability can be ensured by adjusting the weight molecular weight of the urethane acrylate oligomer and by forming a thin coating film. However, this method limits the choice of urethane acrylate oligomer, and designing a low molecular weight leads to a decrease in coating film strength. Similarly, forming a thin film also leads to a decrease in coating film strength. Furthermore, although these methods can guarantee some ease of molding, they do not lead to a fundamental solution to problems such as cracking of the coating film. In addition, weather-resistant adhesion is not sufficient.

[0008] Patent Document 3 describes that by using colloidal silica modified with a mercaptosilane compound that can bond with acrylic urethane, a polyfunctional compound, superior coating strength and bendability are achieved compared to conventional surface-modified colloidal silica. However, there is still much room for improvement in the design and formulation of the curable resin, which constitutes the majority of the cured coating film and greatly affects its physical properties. Further improvements are needed regarding the hardness, moldability, and weather-resistant adhesion of the cured coating film.

[0009] Therefore, there is a need for a hardness that can adequately protect the substrate and the decorated molded product, a moldability that can be flexibly applied to increasingly complex decorated molded products, and weather-resistant adhesion, as well as further improvements thereto. The present invention aims to provide an active energy ray curable coating composition that can form a cured coating film with excellent hardness, moldability, and weather-resistant adhesion, as well as a laminate and a decorative sheet using the same.

[0010] The present invention has the following aspects: [1] An active energy ray curable coating composition comprising: a urethane (meth)acrylate resin (A), a (meth)acryloyl group-containing monomer (B), and inorganic oxide particles (C), wherein the urethane (meth)acrylate resin (A) contains a structure based on isophorone diisocyanate, the (meth)acryloyl group-containing monomer (B) contains a monofunctional monomer (B1) containing one (meth)acryloyl group in its molecule and a polyfunctional monomer (B2) containing two or more (meth)acryloyl groups in its molecule, the mass ratio of the monofunctional monomer (B1) to the polyfunctional monomer (B2) in terms of solid content is 0.3 to 1.2, and the average particle diameter of the inorganic oxide particles (C) is 90 nm or less. A paint composition wherein the content of the urethane (meth)acrylate resin (A) on a solid content basis is 65.0 to 85.0% by mass with respect to the total mass of solids of the paint composition. [2] The paint composition according to [1], wherein the content of the (meth)acryloyl group-containing monomer (B) on a solid content basis is 5.0 to 16.0% by mass with respect to the total mass of solids of the paint composition. [3] The paint composition according to [1] or [2], wherein the polyfunctional monomer (B2) contains 3 to 10 (meth)acryloyl groups in its molecule. [4] The paint composition according to any one of [1] to [3], wherein the glass transition temperature of the homopolymer of the monofunctional monomer (B1) is 90 to 160°C. [5] The paint composition according to any one of [1] to [4], wherein the inorganic oxide particles (C) are at least one selected from the group consisting of alumina particles and silica particles. [6] The paint composition according to any one of [1] to [5], wherein the content of the inorganic oxide particles (C) on a solid content basis is 3.0 to 14.0% by mass relative to the total mass of solids of the paint composition. [7] The paint composition according to any one of [1] to [6], further containing a (meth)acryloyl polymer (D), wherein the double bond equivalent of the (meth)acryloyl polymer (D) is 500 to 2000 g / eq. [8] The paint composition according to [7], wherein the content of the (meth)acryloyl polymer (D) on a solid content basis is 1.0 to 6.0% by mass relative to the total mass of solids of the paint composition.[9] A paint composition according to any one of [1] to [8], wherein the elongation of a laminate prepared by the following preparation method is 50% or more, as determined by the following measurement method. [Preparation method of laminate] A paint composition is applied to the surface of the polymethyl methacrylate layer of a 254 μm thick laminated film, in which a polymethyl methacrylate layer and a polycarbonate layer are laminated in this order, so that the thickness of the coating film after drying is 3.6 μm, and dried at 80°C for 3 minutes, and the resulting coating film is exposed to an integrated light amount of 300 mJ / cm at a wavelength of 365 nm. ２ Ultraviolet light is irradiated in such a manner to form a cured coating film, and a laminate of the laminated film and the cured coating film is obtained. [Method for measuring elongation] A test piece with a width of 15 mm and a length of 110 mm is cut out from the laminate, and a tensile test is performed under the conditions of a chuck distance of 60 mm, a temperature of 160°C, and a tensile strength of 50 mm / min, and the chuck distance at the time when a crack occurs in the cured coating film of the laminate is measured, and the elongation is calculated using the following formula 1. Elongation = (x2 - x1) / x1 × 100 ...Formula 1 Where x1 is the chuck distance before the tensile test (60 mm), and x2 is the chuck distance at the time when a crack occurs.

[10] A laminate comprising a plastic film and a cured coating film of any of the paint compositions described in [1] to [9] formed on at least one surface of the plastic film.

[11] A decorative sheet comprising the laminate described in

[10] .

[0011] The present invention also has the following embodiments: [1] An active energy ray curable coating composition comprising: a urethane (meth)acrylate resin (A); a (meth)acryloyl group-containing monomer (B) (excluding fluorine-based surfactants); and inorganic oxide particles (C), wherein the urethane (meth)acrylate resin (A) contains a structure based on isophorone diisocyanate, the number of (meth)acryloyl groups contained in the molecule of the urethane (meth)acrylate resin (A) is 4 to 12, the weight-average molecular weight is 5,000 to 80,000, and the amount of urethane bond is 3.0 × 10 －３ ~5.6 x 10 －３A paint composition wherein the concentration is eq / g, and the (meth)acryloyl group-containing monomer (B) contains a monofunctional monomer (B1) containing one (meth)acryloyl group in its molecule and a polyfunctional monomer (B2) containing three to ten (meth)acryloyl groups in its molecule, the glass transition temperature of the homopolymer of the monofunctional monomer (B1) is 90 to 160°C, the mass ratio of the monofunctional monomer (B1) to the polyfunctional monomer (B2) in terms of solid content is 0.3 to 1.2, the average particle size of the inorganic oxide particles (C) is 90 nm or less, and the content of the urethane (meth)acrylate resin (A) in terms of solid content is 65.0 to 85.0% by mass relative to the total mass of solid content of the paint composition. [2] The paint composition according to [1], wherein the content of the (meth)acryloyl group-containing monomer (B) on a solid content basis is 5.0 to 16.0% by mass with respect to the total mass of solids of the paint composition. [3] The paint composition according to [1] or [2], wherein the urethane (meth)acrylate resin (A) is a reaction product of a polyisocyanate compound containing at least isophorone diisocyanate, a polyol compound, and a monomer containing a hydroxyl group and a (meth)acryloyl group, and contains a structure based on the polyisocyanate compound, a structure based on the polyol compound, and a structure based on the monomer containing a hydroxyl group and a (meth)acryloyl group, and the ratio of the structure based on isophorone diisocyanate to the total mass of the structure based on the polyisocyanate compound is 50% by mass or more. [4] The paint composition according to any one of [1] to [3], wherein the inorganic oxide particles (C) are at least one selected from the group consisting of alumina particles and silica particles. [5] The paint composition according to any one of [1] to [4], wherein the content of the inorganic oxide particles (C) on a solid content basis is 3.0 to 14.0% by mass relative to the total mass of solids of the paint composition. [6] The paint composition according to any one of [1] to [5], further containing a (meth)acryloyl polymer (D), wherein the double bond equivalent of the (meth)acryloyl polymer (D) is 500 to 2000 g / eq.[7] The paint composition according to [6], wherein the content of the (meth)acryloyl polymer (D) on a solid content basis is 1.0 to 6.0% by mass relative to the total mass of solids of the paint composition. [8] The paint composition according to any one of [1] to [7], wherein the elongation of a laminate prepared by the following preparation method is 50% or more, as determined by the following measurement method. [Preparation method of laminate] A paint composition is applied to the surface of the polymethyl methacrylate layer of a 254 μm thick laminated film in which a polymethyl methacrylate layer and a polycarbonate layer are laminated in this order, such that the thickness of the coating film after drying is 3.6 μm, and the coating film is dried at 80°C for 3 minutes, and the accumulated light amount at a wavelength of 365 nm is 300 mJ / cm. ２ Ultraviolet light is irradiated in such a manner to form a cured coating film, and a laminate of the laminated film and the cured coating film is obtained. [Method for measuring elongation] A test piece with a width of 15 mm and a length of 110 mm is cut out from the laminate, and a tensile test is performed under the conditions of a chuck distance of 60 mm, a temperature of 160°C, and a tensile strength of 50 mm / min, and the chuck distance at the time when a crack occurs in the cured coating film of the laminate is measured, and the elongation is calculated using the following formula 1. Elongation = (x2 - x1) / x1 × 100 ...Formula 1 Where x1 is the chuck distance before the tensile test (60 mm), and x2 is the chuck distance at the time when a crack occurs. [9] A laminate comprising a plastic film and a cured coating film of any of the paint compositions described in [1] to [8] formed on at least one surface of the plastic film.

[10] A decorative sheet comprising the laminate described in [9].

[0012] According to the present invention, it is possible to provide an active energy ray curable coating composition that can form a cured coating film with excellent hardness, moldability, and weather-resistant adhesion, as well as a laminate and decorative sheet using the same.

[0013] The present invention will now be described in detail. The following embodiments are merely illustrative for illustrating the present invention and are not intended to limit the present invention to these embodiments. The present invention can be implemented in various forms without departing from its spirit. In this specification, "coating film" refers to a coating film formed from the coating composition of the present invention. "Solid content" refers to the components of the coating composition excluding volatile media such as solvents, and is the component that ultimately forms the coating film. Specifically, it is measured in accordance with JIS K 5601-1-2:2008. The term "(meth)acrylic" includes both "acrylic" and "methacrylic," and the same applies to the terms "(meth)acrylate" and "(meth)acryloyl." The "weight-average molecular weight" and "number-average molecular weight" of the resin are values ​​on a standard polystyrene basis, measured by gel permeation chromatography (GPC). The "~" indicating a numerical range means that the values ​​written before and after it are included as the lower and upper limits.

[0014] [Paint Composition] The paint composition of this embodiment is an active energy ray curable paint composition containing a urethane (meth)acrylate resin (A), a (meth)acryloyl group-containing monomer (B), and inorganic oxide particles (C). The paint composition of this embodiment may further contain a (meth)acryloyl polymer (D). The paint composition of this embodiment may further contain a photopolymerization initiator (E). The paint composition of this embodiment may further contain an organic solvent. The paint composition of this embodiment may further contain other components as needed, within a range that does not impair the effects of the present invention.

[0015] <Urethane (meth)acrylate resin (A)> Urethane (meth)acrylate resin is a resin that contains urethane bonds and (meth)acryloyl groups in its structure and is curable by active energy rays. Urethane (meth)acrylate resin is typically a reaction product of a polyisocyanate compound, a polyol compound, and a monomer containing hydroxyl groups and (meth)acryloyl groups, and contains a structure based on the polyisocyanate compound, a structure based on the polyol compound, and a structure based on the monomer containing hydroxyl groups and (meth)acryloyl groups.

[0016] In this embodiment, the urethane (meth)acrylate resin (A) contains a structure based on isophorone diisocyanate. By containing a structure based on isophorone diisocyanate, the cured coating film has excellent moldability and chemical resistance. The urethane (meth)acrylate resin (A) may further contain structures based on other polyisocyanate compounds other than isophorone diisocyanate. From the viewpoint of maintaining excellent moldability, the ratio of the structure based on isophorone diisocyanate to the total mass of the structure based on polyisocyanate compounds is preferably 50% by mass or more, more preferably 75% by mass or more, particularly preferably 90% by mass or more, and may also be 100% by mass. The ratio of the structure based on isophorone diisocyanate to the total mass of the structure based on polyisocyanate compounds is preferably 50 to 100% by mass, more preferably 75 to 100% by mass, and particularly preferably 90 to 100% by mass.

[0017] Other isocyanate compounds include, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4-diisocyanate, 2,2-diphenylpropane-4,4-diisocyanate, 3,3-dimethyldiphenylmethane-4,4-diisocyanate, 4,4-diphenylpropane diisocyanate, m-phenylene diisocyanate, and p-phenylene diisocyanate. Examples include aromatic diisocyanates such as nate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, and 3,3-dimethoxydiphenyl-4,4-diisocyanate; aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate; and alicyclic diisocyanates such as norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. In the synthesis of urethane (meth)acrylate resin (A), these isocyanate compounds may be used as is, or they may be used as trimers, dimers, adducts, biurets, allophanates, or urea-modified compounds modified with polyhydric alcohols such as nurates, etc. Other polyisocyanate compounds may be used individually or in combination of two or more.

[0018] Examples of polyol compounds include polyester polyols, polycarbonate polyols, and polyether polyols. Polyol compounds may be used individually or in combination of two or more.

[0019] Examples of polyester polyols include polyester polyols or polyesteramide polyols obtained by a dehydration polycondensation reaction between polycarboxylic acids and polyhydric alcohols or secondary to tertiary amines. Examples of polycarboxylic acids include succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, orthophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, hexahydroorthophthalic acid, naphthalenedicarboxylic acid, and trimellitic acid, as well as their acid esters and acid anhydrides. One type of polycarboxylic acid may be used alone, or two or more types may be used in combination. Examples of polyhydric alcohols include low molecular weight alcohol compounds such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanedimethanol, ethylene oxide or propylene oxide adducts of bisphenol A, trimethylolpropane, glycerin, and pentaerythritol, as well as low molecular weight amino alcohol compounds such as monoethanolamine and diethanolamine. Polyhydric alcohols may be used individually or in combination of two or more. Examples of secondary and tertiary amines include low molecular weight amine compounds such as hexamethylenediamine, xylylenediamine, and isophoronediamine. Secondary and tertiary amines may be used individually or in combination of two or more. Examples of polyester polyols include lactone-based polyester polyols obtained by ring-opening polymerization of cyclic ester (lactone) monomers such as ε-caprolactone and γ-valerolactone using low molecular weight alcohol compounds and low molecular weight amino alcohol compounds as initiators.

[0020] Examples of polycarbonate polyols include those obtained by the dehydrochlorination reaction of a low molecular weight alcohol compound used in the synthesis of polyester polyols with phosgene; and those obtained by the transesterification reaction of this low molecular weight alcohol compound with carbonate compounds such as diethylene carbonate, dimethyl carbonate, diethyl carbonate, and diphenyl carbonate.

[0021] Examples of polyether polyols include polyoxyethylene polyols, polyoxypropylene polyols, polytetramethylene ether polyols, and polyoxyethylene polyoxypropylene polyols, which are obtained by ring-opening polymerization of alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide, and tetrahydrofuran, using low molecular weight alcohol compounds, low molecular weight amine compounds, and low molecular weight amino alcohol compounds, as well as phenols, which are used as initiators in the synthesis of polyester polyols. Examples of polyether polyols include polyester ether polyols obtained by using the aforementioned polyester polyols and polycarbonate polyols as initiators.

[0022] Low molecular weight alcohol compounds may be used as the polyol compound. The number of hydroxyl groups per molecule of the low molecular weight alcohol is preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 or 3. Examples of low molecular weight alcohols include alcohols in which two or more hydrogen atoms of an alkane are substituted with hydroxyl groups. Alternatively, a compound having an etheric oxygen atom between the carbon-carbon bonds of an alkane may be used instead of the above alkane. Examples of low molecular weight alcohols include the polyhydric alcohols described in the raw materials for polyester polyols.

[0023] The molecular weight of the polyol compound is preferably 50 to 500 g / mol, more preferably 60 to 300 g / mol, and particularly preferably 62 to 100 g / mol. If the molecular weight of the polyol compound exceeds the above upper limit, the amount of urethane bonding in the urethane (meth)acrylate resin (A) decreases, which tends to reduce chemical resistance and pencil hardness. If the molecular weight of the polyol compound is below the above lower limit, moldability tends to decrease.

[0024] The theoretical hydroxyl value of the polyol compound is preferably 1200 to 1850 mg KOH / g, more preferably 1400 to 1840 mg KOH / g, and particularly preferably 1600 to 1830 mg KOH / g. If the theoretical hydroxyl value of the polyol compound exceeds the above upper limit, moldability tends to decrease. If the average molecular weight of the polyol compound is below the above lower limit, the amount of urethane bonding in the urethane (meth)acrylate resin (A) decreases, which tends to reduce chemical resistance and pencil hardness.

[0025] The number of hydroxyl groups in monomers containing hydroxyl groups and (meth)acryloyl groups is preferably 1 to 3, more preferably 1 to 2, and even more preferably 1. The number of functional groups in monomers containing hydroxyl groups and (meth)acryloyl groups is preferably 2 to 10, more preferably 3 to 6, and even more preferably 3 to 5. The molecular weight of monomers containing hydroxyl groups and (meth)acryloyl groups is preferably 100 to 600, more preferably 150 to 500, and even more preferably 200 to 400. The structure of the part of monomers containing hydroxyl groups and (meth)acryloyl groups other than the hydroxyl groups and (meth)acryloyl groups consists of carbon, hydrogen, and oxygen, and is preferably linear or branched. Examples of monomers containing a hydroxyl group and a (meth)acryloyl group include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, and 4-hydroxybutyl(meth)acrylate.

[0026] The weight average molecular weight of the urethane (meth)acrylate resin (A) is 5,000 to 80,000, preferably 10,000 to 70,000, and particularly preferably 30,000 to 60,000. When the weight average molecular weight of the urethane (meth)acrylate resin (A) is at least the above lower limit value, the formability of the cured coating film is more excellent. When the weight average molecular weight of the urethane (meth)acrylate resin (A) is at most the above upper limit value, the pencil hardness of the cured coating film is more excellent. Incidentally, the weight average molecular weight of the urethane (meth)acrylate resin (A) may be 10,000 to 100,000, or may be 20,000 to 80,000.

[0027] The number of functional groups of the urethane (meth)acrylate resin (A) is 4 to 12, preferably 4 to 10, and particularly preferably 6 to 9. When the number of functional groups of the urethane (meth)acrylate resin (A) is at least the above lower limit value, the pencil hardness and scratch resistance of the cured coating film are more excellent. When the number of functional groups of the urethane (meth)acrylate resin (A) is at most the above upper limit value, the formability of the cured coating film is more excellent. The number of functional groups of the urethane (meth)acrylate resin (A) may be 1 to 16, may be 4 to 12, or may be 6 to 10. The number of functional groups indicates the number of (meth)acryloyl groups.

[0028] The amount of urethane bonds in the urethane (meth)acrylate resin (A) is 3.0×10 －３ to 5.6×10 －３ eq / g, preferably 3.5×10 －３ to 5.5×10 －３ eq / g, and particularly preferably 4.0×10 －３ to 5.4×10 －３eq / g is more preferable. If the amount of urethane bonds in the urethane (meth)acrylate resin (A) is less than the above lower limit, the pencil hardness, scratch resistance, chemical resistance, and tack-free properties of the dried coating tend to decrease. If the amount of urethane bonds in the urethane (meth)acrylate resin (A) exceeds the above upper limit, the weather-resistant adhesion, paint stability, and coating suitability tend to decrease. The amount of urethane bonds is calculated as follows: Number of isocyanate groups: number of moles of isocyanate compound used in the production of the urethane (meth)acrylate resin × number of isocyanate groups contained in the isocyanate compound. Number of hydroxyl groups: number of moles of hydroxyl group-containing compound used in the production of the urethane (meth)acrylate resin × number of hydroxyl groups contained in the hydroxyl group-containing compound. Number of amino groups: number of moles of amino group-containing compound used in the production of the urethane (meth)acrylate resin × number of amino groups contained in the amino group-containing compound. Number of urethane groups: The smaller of the number of isocyanate groups and the sum of the number of hydroxyl groups and amino groups. Amount of urethane bonds: Number of urethane groups ÷ Total amount (g) of raw materials used in the synthesis of urethane (meth)acrylate resin (A). However, the amount of raw materials used does not include the amount of raw materials that did not react and were not incorporated as units into the urethane (meth)acrylate resin. In other words, the amount of urethane bonds in this specification means the total amount of urethane bonds and urea bonds.

[0029] The amount of (meth)acryloyl groups in urethane (meth)acrylate resin (A) is 1.0 × 10 －３ ~6.0 x 10 －３ eq / g is preferred, and 2.0 × 10 －３ ~5.0 x 10 －３ eq / g is more preferable, 2.5 × 10 －３ ~4.5 x 10 －３eq / g is particularly preferred. If the amount of (meth)acryloyl groups in the urethane (meth)acrylate resin (A) is less than the above lower limit, the chemical resistance and scratch resistance tend to decrease. If the amount of (meth)acryloyl groups in the urethane (meth)acrylate resin (A) exceeds the above upper limit, the moldability tends to decrease. The amount of (meth)acryloyl groups is calculated as follows. Number of (meth)acryloyl groups: The number of moles of the monomer having a hydroxyl group and a (meth)acryloyl group used in the production of the urethane (meth)acrylate resin × the number of (meth)acryloyl groups contained in the monomer having a hydroxyl group and a (meth)acryloyl group. Amount of (meth)acryloyl groups: The number of (meth)acryloyl groups ÷ the total amount (g) of the raw materials used in the synthesis of the urethane (meth)acrylate resin (A). However, regarding the amount of raw materials used, the amount of raw materials that are not incorporated into the urethane (meth)acrylate resin as a unit due to unreactedness is not included.

[0030] The content of the urethane (meth)acrylate resin (A) in terms of solid content is 65.0 to 85.0% by mass, preferably 68.0 to 82.0% by mass, and more preferably 70.0 to 80.0% by mass, based on the total mass of the solid content of the coating composition. When the content of the urethane (meth)acrylate resin (A) is not less than the above lower limit, the moldability of the cured coating film is excellent. When the content of the urethane (meth)acrylate resin (A) is not more than the above upper limit, the pencil hardness and scratch resistance of the cured coating film are excellent. The content of the urethane (meth)acrylate resin (A) in terms of solid content is preferably 15.0 to 35.0% by mass, more preferably 18.0 to 32.0% by mass, and particularly preferably 20.0 to 30.0% by mass, based on the total mass of the coating composition.

[0031] The urethane (meth)acrylate resin (A) can be produced, for example, by reacting an isocyanate compound containing at least isophorone diisocyanate, a polyol compound, and a monomer having a hydroxyl group and a (meth)acryloyl group by a conventionally known method without a solvent or in an organic solvent.

[0032] <(Meth)acryloyl group-containing monomer (B)>The (meth)acryloyl group-containing monomer is a monomer containing a (meth)acryloyl group in its structure and is curable by active energy rays. Note that fluorosurfactants are excluded from the (meth)acryloyl group-containing monomer. That is, the (meth)acryloyl group-containing monomer does not have a fluorine atom.

[0033] The coating composition of the present embodiment contains, as the (meth)acryloyl group-containing monomer (B), a monofunctional monomer (B1) containing one (meth)acryloyl group in the molecule and a polyfunctional monomer (B2) containing two or more (meth)acryloyl groups in the molecule. In one embodiment, the polyfunctional monomer (B2) has 3 to 10 (meth)acryloyl groups in the molecule.

[0034] The molecular weight of the monofunctional monomer (B1) is preferably 80 to 500, more preferably 100 to 400, and even more preferably 110 to 250.

[0035] Examples of monofunctional monomers (B1) include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, isoamyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl (meth)acrylate, 1,4-butylene glycol mono (meth)acrylate, and methoxyethyl Examples include (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, hexahydrophthalyloxyethyl (meth)acrylate, hexahydrophthalyloxypropyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, isobornyl (meth)acrylate, vinylcyclohexane, (meth)acryloylmorpholin, and N-vinylpyrrolidone.

[0036] In particular, monofunctional monomer (B1) is preferably a radical polymerizable monofunctional monomer having an alicyclic or heterocyclic structure, from the viewpoint of having higher moldability. Among these, 3,3,5-trimethylcyclohexyl (meth)acrylate, hexahydrophthalyloxyethyl (meth)acrylate, hexahydrophthalyloxypropyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, isobornyl (meth)acrylate, vinylcyclohexane, (meth)acryloylmorpholin, and N-vinylpyrrolidone are preferred. Monofunctional monomer (B1) may be used alone or in combination of two or more.

[0037] The glass transition temperature of the homopolymer of the monofunctional monomer (B1) is 90 to 160°C, preferably 100 to 155°C, and particularly preferably 110 to 150°C. If the glass transition temperature of the homopolymer of the monofunctional monomer (B1) is above the lower limit, the pencil hardness of the cured coating film is better. If the glass transition temperature of the homopolymer of the monofunctional monomer (B1) is below the upper limit, the moldability of the cured coating film is better. Regarding the glass transition temperature of the monomer homopolymer, if the manufacturer has disclosed a value, that value shall be adopted. If the manufacturer has not disclosed a value, the value described in Polymer Handbook 4th Edition (Wiley-Interscience 2003) shall be adopted. If the value is not described in the aforementioned literature, the value measured by differential scanning calorimeter (DSC) shall be adopted. In the case of DSC, the glass transition temperature is determined from the intersection of the baseline and the tangent to the endothermic curve in the curve (DSC curve) obtained by heating 10 mg of the homopolymer to a sufficiently high molecular weight so that its glass transition temperature reaches the limit value, in accordance with JIS K 7121:2012, from -100°C to 200°C at a rate of 20°C / min.

[0038] The formula weight of the portion of the polyfunctional monomer (B2) other than the (meth)acryloyl group is preferably 60 to 500, more preferably 70 to 400, and even more preferably 80 to 300. The structure of the portion of the polyfunctional monomer (B2) other than the (meth)acryloyl group consists of carbon, hydrogen, and oxygen, and is preferably linear or branched.

[0039] Examples of polyfunctional monomers (B2) include trifunctional monomers such as trimethylolpropane tri(meth)acrylate, trimethylolpropaneethoxytri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerylpropoxytri(meth)acrylate, tris(2-acryloyloxyethyl) isocyanurate, and caprolactone-modified tris(2-acryloyloxyethyl) isocyanurate; tetrafunctional monomers such as pentaerythritol tetra(meth)acrylate and ditrimethylolpropane tetra(meth)acrylate; pentafunctional monomers such as dipentaerythritol penta(meth)acrylate; hexafunctional monomers such as dipentaerythritol hexa(meth)acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate; and decafunctional monomers such as tetrapentaerythritol deca(meth)acrylate. The polyfunctional monomer (B2) may be used alone or in combination of two or more types.

[0040] The number of (meth)acryloyl groups (functional group count) contained in the molecule of the polyfunctional monomer (B2) is 3 to 10, preferably 4 to 10, and particularly preferably 5 to 10. When the number of functional groups of the polyfunctional monomer (B2) is above the lower limit, the pencil hardness and scratch resistance of the cured coating film are better. When the number of functional groups of the polyfunctional monomer (B2) is below the upper limit, the moldability of the cured coating film is better.

[0041] In the coating composition of this embodiment, the mass ratio of monofunctional monomer (B1) to polyfunctional monomer (B2) in terms of solid content (hereinafter also referred to as "B1 / B2") is 0.3 to 1.2, preferably 0.4 to 1.1, and more preferably 0.45 to 1.0. When B1 / B2 is above the lower limit, the pencil hardness, scratch resistance, and moldability of the cured coating film are excellent. When B1 / B2 is below the upper limit, the pencil hardness and scratch resistance of the cured coating film are excellent.

[0042] The content of (meth)acryloyl group-containing monomer (B) on a solids basis is preferably 5.0 to 16.0% by mass, more preferably 8.0 to 15.0% by mass, and particularly preferably 10.0 to 14.0% by mass, relative to the total mass of solids in the paint composition. When the content of (meth)acryloyl group-containing monomer (B) is above the lower limit, the pencil hardness and scratch resistance of the cured coating film are better. When the content of (meth)acryloyl group-containing monomer (B) is below the upper limit, the moldability of the cured coating film is better. The content of (meth)acryloyl group-containing monomer (B) on a solids basis is preferably 1.5 to 5.5% by mass, more preferably 2.0 to 5.2% by mass, and particularly preferably 3.0 to 5.0% by mass, relative to the total mass of the paint composition.

[0043] <Inorganic Oxide Particles (C)> Examples of inorganic oxide particles (C) include alumina particles, silica particles, titanium oxide particles, zirconium oxide particles, tin oxide particles, antimond-doped tin oxide particles, and zinc oxide particles. Among these, alumina particles and silica particles are preferred in terms of haze, hardness, and cost. The inorganic oxide particles (C) may or may not be surface treated. From the viewpoint of hardness and paint stability, those having polymerizable functional groups on the surface are preferred, and those having (meth)acryloyl groups on the surface are particularly preferred. One type of inorganic oxide particle (C) may be used alone, or two or more types may be used in combination.

[0044] The average particle diameter of the inorganic oxide particles (C) is 90 nm or less, preferably 80 nm or less, and more preferably 70 nm or less. When the average particle diameter of the inorganic oxide particles (C) is below the above upper limit, the moldability and transparency (haze evaluation) of the cured coating film are excellent. The lower limit of the average particle diameter of the inorganic oxide particles (C) is not particularly limited, but it is preferably 1 nm or more from the viewpoint that aggregation of inorganic oxide particles (C) is less likely to occur. The average particle diameter of the inorganic oxide particles (C) is preferably 1 to 90 nm, more preferably 1 to 80 nm, and even more preferably 1 to 70 nm. In this specification, the average particle diameter of the inorganic oxide particles (C) refers to the particle diameter at 50% of the cumulative value (D50) in the volume-based particle size distribution, and can be determined by laser diffraction / scattering method.

[0045] The content of inorganic oxide particles (C) on a solid content basis is preferably 3.0 to 14.0% by mass, more preferably 3.5 to 10.0% by mass, and particularly preferably 4.0 to 8.0% by mass, relative to the total mass of solids in the paint composition. When the content of inorganic oxide particles (C) is above the lower limit, the pencil hardness and scratch resistance of the cured coating film are better. When the content of inorganic oxide particles (C) is below the upper limit, the moldability and transparency (haze evaluation) of the cured coating film are better. The content of inorganic oxide particles (C) on a solid content basis is preferably 1.0 to 4.5% by mass, more preferably 1.2 to 3.0% by mass, and particularly preferably 1.4 to 2.0% by mass, relative to the total mass of the paint composition.

[0046] <(meth)acryloyl polymer (D)> The coating composition of this embodiment may further contain (meth)acryloyl polymer (D) for the purpose of improving adhesion to plastic films, such as plastic films containing (meth)acrylic resins including polymethyl methacrylate (PMMA). (meth)acryloyl polymer (D) is a resin that does not have urethane bonds and has (meth)acryloyl groups at the ends of its side chains, and is curable by active energy rays.

[0047] (Meth)acryloyl polymer (D) can be obtained, for example, by the following methods 1 or 2: Method 1: Polymerizing a (meth)acrylate containing a glycidyl group, and then adding the glycidyl group of the side chain of the resulting polymer to (meth)acrylic acid. Method 2: Polymerizing (meth)acrylic acid, and then adding the carboxyl group of the side chain of the resulting polymer to a (meth)acrylate containing a glycidyl group. In Method 1, the (meth)acrylate containing a glycidyl group may be copolymerized with other monomers. In Method 2, (meth)acrylic acid may be copolymerized with other monomers.

[0048] Examples of (meth)acrylates having a glycidyl group include glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, and (3,4-epoxycyclohexyl)methyl (meth)acrylate. A single (meth)acrylate having a glycidyl group may be used, or two or more may be used in combination.

[0049] The weight-average molecular weight of (meth)acryloyl polymer (D) is preferably 10,000 to 100,000, more preferably 20,000 to 80,000, and particularly preferably 30,000 to 50,000. When the weight-average molecular weight of (meth)acryloyl polymer (D) is above the lower limit, the moldability of the cured coating film is better. When the weight-average molecular weight of (meth)acryloyl polymer (D) is below the upper limit, the pencil hardness and scratch resistance of the cured coating film are better.

[0050] The number average molecular weight of (meth)acryloyl polymer (D) is preferably 5,000 to 80,000, more preferably 10,000 to 50,000, and particularly preferably 15,000 to 35,000. When the number average molecular weight of (meth)acryloyl polymer (D) is above the lower limit, the moldability of the cured coating film is better. When the number average molecular weight of (meth)acryloyl polymer (D) is below the upper limit, the compatibility is better.

[0051] The double bond equivalent of (meth)acryloyl polymer (D) is preferably 500 to 2000 g / eq, more preferably 600 to 1800 g / eq, and particularly preferably 700 to 1500 g / eq. When the double bond equivalent of (meth)acryloyl polymer (D) is above the lower limit, the moldability of the cured coating film is better. When the double bond equivalent of (meth)acryloyl polymer (D) is below the upper limit, the pencil hardness and scratch resistance of the cured coating film are better. The double bond equivalent of (meth)acryloyl polymer (D) is calculated by the number-average molecular weight / number of functional groups.

[0052] The content of (meth)acryloyl polymer (D) on a solids basis is preferably 1.0 to 6.0% by mass, more preferably 1.5 to 5.5% by mass, and particularly preferably 2.0 to 5.0% by mass, relative to the total mass of solids in the paint composition. When the content of (meth)acryloyl polymer (D) is above the lower limit, the boiling adhesion is better. When the content of (meth)acryloyl polymer (D) is below the upper limit, the pencil hardness of the cured coating film is better. The content of (meth)acryloyl polymer (D) on a solids basis is preferably 0.3 to 2.0% by mass, more preferably 0.5 to 1.8% by mass, and particularly preferably 0.8 to 1.5% by mass, relative to the total mass of the paint composition.

[0053] <Photopolymerization initiator (E)> Examples of photopolymerization initiators (E) include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-cyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and 4-methylbenzophenone. One type of photopolymerization initiator (E) may be used alone, or two or more types may be used in combination. Furthermore, a known curing accelerator may be used in combination with the photopolymerization initiator (E).

[0054] The content of the photopolymerization initiator (E) is preferably 2 to 10% by mass, more preferably 3 to 9% by mass, and particularly preferably 4 to 8% by mass, based on the total mass of the paint composition. If the content of the photopolymerization initiator (E) is above the lower limit, active energy ray curing proceeds sufficiently, and the pencil hardness and scratch resistance of the cured coating film are better. If the content of the photopolymerization initiator (E) is below the upper limit, unreacted photopolymerization initiator (E), which has a low molecular weight, is less likely to remain in the cured coating film, and the pencil hardness and scratch resistance of the cured coating film are better.

[0055] <Organic Solvents> Examples of organic solvents include esters such as ethyl acetate, propyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and anone; hydrocarbons such as benzene, toluene, xylene, and n-hexane; alcohols such as ethyl alcohol, isopropyl alcohol, n-butyl alcohol, and propylene glycol monomethyl ether; and glycol ethers such as propylene glycol monomethyl ether and butyl cellosolve.

[0056] The content of the organic solvent is preferably 30.0 to 95.0% by mass, more preferably 40.0 to 90.0% by mass, and particularly preferably 50.0 to 80.0% by mass, based on the total mass of the paint composition. When the content of the organic solvent is above the lower limit, the paint stability is better. When the content of the organic solvent is below the upper limit, the printability is better.

[0057] <Other Ingredients> Other ingredients include additives such as silane coupling agents, leveling agents, defoamers, antioxidants, thermoplastic resins, antistatic agents, waxes, heat stabilizers, flame retardants, deodorants, ultraviolet absorbers (UVA), radical scavengers (HALS), surfactants, silicone-based surfactants, and fluorine-based surfactants. Additives may be used individually or in combination of two or more.

[0058] The inclusion of UV absorbers and radical scavengers is preferable because it can further improve the weather resistance of the resulting cured film. The total content of UV absorbers and radical scavengers is preferably 0.1 to 5.0% by mass, and more preferably 0.5 to 2.0% by mass, based on the total mass of the urethane (meth)acrylate resin (A), (meth)acryloyl group-containing monomer (B), and (meth)acryloyl polymer (D) in terms of solid content.

[0059] The inclusion of silicone-based surfactants and fluorine-based surfactants is preferable because it can improve the solvent resistance and antifouling properties of the resulting cured coating film. The total content of silicone-based surfactants and fluorine-based surfactants is preferably 0.05 to 5.0% by mass, and more preferably 0.1 to 2.0% by mass, based on the total mass of the urethane (meth)acrylate resin (A), (meth)acryloyl group-containing monomer (B), and (meth)acryloyl polymer (D) in terms of solid content.

[0060] <Mechanism of Action> The isophorone diisocyanate-based structure of urethane (meth)acrylate resin (A) contributes to improving the moldability of the cured coating film. Isophorone diisocyanate has a cyclohexane ring structure, and it is believed that the introduction of this structure into the cured coating film makes the cured coating film highly flexible in all directions, thereby improving moldability. Polyisocyanates with aromatic ring structures, such as toluene diisocyanate, have a rigid structure and therefore cannot impart flexibility to the cured coating film, resulting in significantly inferior moldability. On the other hand, polyisocyanates with linear structures, such as hexamethylene diisocyanate, can impart some flexibility, but they are inferior in flexibility in the elongation and contraction directions, and furthermore, the steric hindrance near the urethane bond is small, and the intermolecular hydrogen bonds become strong, resulting in insufficient moldability of the cured coating film.

[0061] If the amount of urethane bonding in urethane (meth)acrylate resin (A) is too low, the pencil hardness and scratch resistance will decrease. This is thought to be because the intermolecular connections formed by hydrogen bonding in the urethane bonding area will be insufficient. On the other hand, if the amount of urethane bonding is too high, the weather-resistant adhesion will decrease. This is thought to be because the degree of deterioration due to hydrolysis of the urethane bonding area will be greater.

[0062] The polyfunctional monomer (B2) contributes to improved hardness by increasing the crosslinking density and constructing a complex three-dimensional network structure. The monofunctional monomer (B1), being monofunctional, suppresses the decrease in flexibility caused by excessively high crosslinking density in the cured coating film. By combining these in a specific mass ratio, excellent hardness and moldability are achieved. Furthermore, if the glass transition temperature of the homopolymer of the monofunctional monomer (B1) is below the above upper limit, the flexibility of the cured coating film is improved by the heat generated during molding of the decorated molded article under high-temperature conditions (150°C for 30 seconds is listed as an example in

[0113] ). On the other hand, if the glass transition temperature is too low, it negatively affects the hardness. Therefore, by using a monofunctional monomer (B1) with a glass transition temperature within an appropriate range, it is possible to achieve both excellent moldability and hardness.

[0063] <Elongation> The paint composition of this embodiment preferably has an elongation of 20% or more, more preferably 35% or more, and particularly preferably 50% or more, for a laminate prepared by the following manufacturing method, as determined by the following measurement method. Elongation is an indicator of the moldability of the cured coating film. If the elongation is above the above lower limit, it is useful for applications where moldability is required. [Method of preparing the laminate] A 254 μm thick laminated film is made by laminating a polymethyl methacrylate layer and a polycarbonate layer in this order. The paint composition is applied to the surface of the polymethyl methacrylate layer so that the thickness of the coating film after drying is 3.6 μm, and dried at 80°C for 3 minutes. The resulting coating film is then subjected to an integrated light intensity of 300 mJ / cm² at a wavelength of 365 nm. ２A cured coating film is formed by irradiating the laminated film with ultraviolet light to obtain a laminate of the laminated film and the cured coating film. Details are as described in the examples below. [Method for measuring elongation] A test piece with a width of 15 mm and a length of 110 mm is cut from the laminate, and a tensile test is performed under the conditions of a chuck distance of 60 mm, a temperature of 160°C, and a tensile strength of 50 mm / min. The chuck distance is measured at the time when a crack occurs in the cured coating film of the laminate, and the elongation is calculated using the following formula 1. Elongation = (x2 - x1) / x1 × 100 ...Formula 1 Where x1 is the chuck distance before the tensile test (60 mm), and x2 is the chuck distance at the time when a crack occurs.

[0064] <Indentation Modulus> The indentation modulus of the coating composition of this embodiment, obtained by the following measurement method for a laminate produced by the above-described method, is preferably 2 to 15 Gpa, more preferably 3 to 10 Gpa, and particularly preferably 4 to 8 Gpa. The indentation modulus is an indicator of the hardness of the cured coating film. If the indentation modulus is below the lower limit, the pencil hardness and scratch resistance of the cured coating film tend to decrease. If the indentation modulus exceeds the upper limit, the moldability tends to decrease. [Measurement Method for Indentation Modulus] The indentation modulus is measured on the surface of the cured coating film using a nanoindenter (Bruker's "Hyzitron TI Premier") based on the nanoindentation method. A Berkovich indenter is used as the indenter for the nanoindenter. The measurement conditions employ a load control method (indentation load 1000 μN, load 5 seconds / hold 2 seconds / unload 5 seconds), and the average value of the indentation modulus at five points on the coating film surface is obtained.

[0065] <Indentation Hardness> The indentation hardness of the laminate produced by the above-described manufacturing method of the coating composition of this embodiment is preferably 0.1 to 1.5 Gpa, more preferably 0.15 to 1 Gpa, and particularly preferably 0.2 to 0.8 Gpa, as determined by the following measurement method. Indentation hardness is an indicator of the hardness of the cured coating film. If the indentation hardness is below the above lower limit, the moldability of the cured coating film tends to decrease. If the indentation hardness exceeds the above upper limit, the pencil hardness and scratch resistance tend to decrease. [Method for Measuring Indentation Hardness] Indentation hardness is measured on the surface of the cured coating film using a nanoindenter (Bruker's "Hyzitron TI Premier") based on the nanoindentation method. A Berkovich indenter is used as the indenter for the nanoindenter. The measurement conditions employ a load control method (indentation load of 1000 μN, load for 5 seconds / hold for 2 seconds / unload for 5 seconds), and the average value of the indentation hardness at five points on the coating surface is calculated.

[0066] <Manufacturing Method> The paint composition of this embodiment can be manufactured by mixing, for example, a urethane (meth)acrylate resin (A), a (meth)acryloyl group-containing monomer (B), inorganic oxide particles (C), and, if necessary, one or more of a photopolymerization initiator, an organic solvent, and other components. The method of mixing each component is not particularly limited, and each component can be mixed by various methods. When the paint composition contains an organic solvent, typically, the urethane (meth)acrylate resin (A), etc., is dissolved or dispersed in the organic solvent. The method of dissolving or dispersing each component is not particularly limited, and can be done using known dispersers. Examples of dispersers include paint shakers, dissolvers, ball mills, attritors, sand mills, bead mills, dyno mills, roll mills, ultrasonic mills, and high-pressure impact dispersers. In this case, dispersion treatment may be performed once or multiple times using one type of disperser, or dispersion treatment may be performed multiple times using two or more types of dispersers in combination.

[0067] <Effects> The paint composition of this embodiment described above contains the above-mentioned urethane (meth)acrylate resin (A), (meth)acryloyl group-containing monomer (B), and inorganic oxide particles (C), so it can form a cured coating film with excellent hardness and moldability.

[0068] <Applications> The paint composition of this embodiment is suitable for decorative sheets because it can form a cured coating film with excellent hardness and moldability.

[0069] [Laminate] The laminate of this embodiment comprises a plastic film and a cured coating film of the paint composition of this embodiment formed on at least one surface of the plastic film.

[0070] The thickness of the cured coating film can be set appropriately depending on the application. For example, the thickness of the cured coating film is preferably 100 nm to 10 μm, and more preferably 3 to 5 μm.

[0071] Examples of resins that make up the plastic film include polymethyl methacrylate (PMMA), acrylic resins such as polyacrylonitrile, polycarbonate resin (PC), polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), polyphenylene sulfide resin (PPS), modified polyphenylene ether resin (modified PPE), triacetylcellulose resin (TAC), and cycloolefin polymer resin (COP). One type of resin may be used alone, or two or more types may be used in combination. The plastic film may have a single-layer structure or a multi-layer structure.

[0072] As for the plastic film, a single-layer film containing acrylic resin or a multilayer film in which at least one of the outermost layers is a layer containing acrylic resin (acrylic resin layer) is preferred because it has superior surface hardness. Of these, the multilayer film preferably further contains a layer containing PC (PC layer). This makes it possible to improve thermoformability while ensuring excellent surface hardness. Examples of layer configurations for the multilayer film include acrylic resin layer / PC layer and acrylic resin layer / PC layer / acrylic resin layer. The acrylic resin layer / PC layer indicates that the acrylic resin layer and the PC layer are laminated in this order. Other layer configurations are similar.

[0073] From the viewpoint of workability, processability, and physical properties required for protecting the object to be decorated in decorative applications, the thickness of the plastic film is preferably 25 to 500 μm.

[0074] Preferably, at least one surface of the plastic film is surface-treated to improve adhesion with the cured coating. Examples of surface treatments include surface roughening treatments such as primer treatment, sandblasting, and solvent treatment; and oxidation treatments such as corona discharge treatment, chromic acid treatment, and ozone / ultraviolet irradiation treatment. When the laminate is used as a decorative sheet for in-mold transfer, preferably, at least one surface of the plastic film is release-treated to improve peelability with the cured coating. Examples of release treatments include treatment with melamine resin, silicone resin, or fluororesin.

[0075] The laminate of this embodiment may further comprise other layers besides the plastic film and the cured coating, if necessary. For example, a low refractive index layer with a thickness of approximately 100 nm may be further provided on the cured coating of the paint composition of this embodiment. This can provide an anti-reflective effect. An ink layer may further be provided between the plastic film and the cured coating.

[0076] The laminate of this embodiment can be manufactured according to conventionally known methods. For example, a coating composition can be applied to the surface of a plastic film using known coating methods such as roll coating, gravure coating, comma coating, knife coating, die coating, or screen coating, and dried as necessary to form a coating film. Then, the formed coating film can be irradiated with a predetermined dose of active energy rays to harden the coating film and form a cured coating film, thereby obtaining the laminate. The thickness of the coating film can be appropriately set according to the thickness of the cured coating film to be formed. Known devices can be used as the device for irradiating with active energy rays. For example, known ultraviolet irradiation devices such as xenon lamps, metal halide lamps, high-pressure mercury lamps, low-pressure mercury lamps, electrodeless lamps, LED lamps, xenon flash lamps, and excimer lamps can be used as the device for irradiating with ultraviolet rays. The amount of active energy rays irradiated should be sufficient to harden the coating film and can be appropriately set according to the active energy rays used. For example, the amount of ultraviolet rays irradiated can be 200 to 1000 mJ / cm² as the integrated light amount at a wavelength of 365 nm. ２ That is the case.

[0077] <Applications> The laminate of this embodiment is suitable for use as a decorative sheet because it has a cured coating film of the paint composition of this embodiment.

[0078] [Decorative Sheet] The decorative sheet of this embodiment comprises the laminate of this embodiment. The laminate of this embodiment may be used as a decorative sheet as is, or other layers may be laminated onto the laminate of this embodiment to form a decorative sheet. Examples of other layers include an ink layer, an adhesive layer, and a refractive index adjusting layer. Examples of layer configurations for the decorative sheet include cured coating film / plastic film / ink layer / adhesive layer, and cured coating film / ink layer / plastic film / adhesive layer.

[0079] <Applications> Decorative sheets are used to decorate molded products such as building materials, electronic equipment casings, and automotive interior components. Examples of materials for the molded product to be decorated with the decorative sheet include ABS resin, polypropylene resin (PP), polyethylene resin (PE), and polycarbonate resin (PC). It is preferable that the surface of the molded product to be decorated with the decorative sheet has a curved surface. Decorated molded products, in which the molded product has been decorated with the decorative sheet, can be manufactured by known methods. Examples include heat molding such as vacuum forming, film insert molding, and in-mold molding.

[0080] 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. "Parts" means parts by mass. "%" means mass percent unless otherwise specified. "NV" means solids.

[0081] [Raw materials used] <Urethane (meth)acrylate resin (A)> ・A-1: Urethane (meth)acrylate resin obtained in Synthesis Example 1 (number of functional groups 9, weight-average molecular weight 37,000, urethane bond amount 5.36 × 10 －３ eq / g) ・A-2: Urethane (meth)acrylate resin obtained in Synthesis Example 2 (6 functional groups, weight-average molecular weight 5,000, urethane bond amount 5.10 × 10 －３ eq / g) ・A-3: Urethane (meth)acrylate resin obtained in Synthesis Example 3 (6 functional groups, weight-average molecular weight 6,000, urethane bond amount 2.31 × 10 －３ eq / g) ・A-4: Urethane (meth)acrylate resin obtained in Synthesis Example 4 (number of functional groups 9, weight-average molecular weight 74,000, urethane bond amount 2.92 × 10 －３ eq / g) ・A-5: Urethane (meth)acrylate resin obtained in Synthesis Example 5 (number of functional groups 9, weight-average molecular weight 74,000, urethane bond amount 5.93 × 10 －３ eq / g)

[0082] (Synthesis Example 1: Synthesis of A-1) 72 parts glycerin, 520 parts isophorone diisocyanate, 4 parts dibutyltin laurate, 8 parts 2,6-tert-butyl-4-methylphenol (BHT), and 4,800 parts propyl acetate were charged into a three-necked flask and stirred at 80°C for 6 hours. Next, the temperature was lowered to 60°C, then 290 parts ethylene glycol and 1,038 parts isophorone diisocyanate were added, and the temperature was raised again to 80°C and stirred for 6 hours. After that, the temperature was lowered to 60°C, 1,284 parts pentaerythritol triacrylate were added, and the mixture was stirred at 70°C for 6 hours to obtain a solution of a decahylated urethane (meth)acrylate resin (A-1) with a resin solids content of 40%.

[0083] (Synthesis Example 2: Synthesis of A-2) 420 parts of ethylene glycol, 1,883 parts of isophorone diisocyanate, 4 parts of dibutyltin laurate, 8 parts of BHT, and 4,000 parts of propyl acetate were charged into a three-necked flask and stirred at 80°C for 6 hours. Next, the temperature was reduced to 60°C, 1,696 parts of pentaerythritol triacrylate were added, and the mixture was stirred at 70°C for 6 hours to obtain a solution of a hexafunctional urethane (meth)acrylate resin (A-2) with a resin solids content of 50%.

[0084] (Synthesis Example 3: Synthesis of A-3) 1,514 parts of hexamethylene diisocyanate, 3,610 parts of polycarbonate diol (hydroxyl value 140 mg KOH / g, number average molecular weight 800), and 1 part of dibutyltin laurate were charged into a three-necked flask and reacted at 60°C. After confirming the decrease in isocyanate groups, 2,685 parts of pentaerythritol triacrylate and 4 parts of BHT were further charged and reacted at 60°C. Dilution with propyl acetate was performed to obtain a solution of a hexafunctional urethane (meth)acrylate resin (A-3) with a resin solids content of 50%.

[0085] (Synthesis Example 4: Synthesis of A-4) 72 parts glycerin, 520 parts isophorone diisocyanate, 4 parts dibutyltin laurate, 8 parts 2,6-tert-butyl-4-methylphenol (BHT), and 3,900 parts propyl acetate were charged into a three-necked flask and stirred at 80°C for 6 hours. Next, the temperature was lowered to 60°C, then 580 parts PEG500 and 129 parts isophorone diisocyanate were added, and the temperature was raised again to 80°C and stirred for 6 hours. After that, the temperature was lowered to 60°C, 1,284 parts pentaerythritol triacrylate were added, and the mixture was stirred at 70°C for 6 hours to obtain a solution of a decahylated urethane (meth)acrylate resin (A-4) with a resin solids content of 40%.

[0086] (Synthesis Example 5: Synthesis of A-5) 72 parts glycerin, 520 parts isophorone diisocyanate, 4 parts dibutyltin laurate, 8 parts 2,6-tert-butyl-4-methylphenol (BHT), and 6,800 parts propyl acetate were charged into a three-necked flask and stirred at 80°C for 6 hours. Next, the temperature was lowered to 60°C, then 580 parts ethylene glycol and 2,076 parts isophorone diisocyanate were added, and the temperature was raised again to 80°C and stirred for 6 hours. After that, the temperature was lowered to 60°C, 1,284 parts pentaerythritol triacrylate were added, and the mixture was stirred at 70°C for 6 hours to obtain a solution of a decahylated urethane (meth)acrylate resin (A-5) with a resin solids content of 40%.

[0087] <(meth)acryloyl group-containing monomer (B)> (monofunctional monomer (B1)) ・B1-1: Acryloyl morpholine (ACMO) (manufactured by KJ Chemicals Co., Ltd., glass transition temperature of homopolymer 145°C) ・B1-2: Isobornyl acrylate (IBXA) (manufactured by Osaka Organic Chemical Industry Co., Ltd., glass transition temperature of homopolymer 97°C)

[0088] (Polyfunctional monomers (B2)) ・B2-1: NK Ester A-9550 (manufactured by Shin Nakamura Chemical Industry Co., Ltd., 6 functional groups) ・B2-2: Aronics M-305 (PETA) (manufactured by Toagosei Co., Ltd., 3-4 functional groups) ・B2-3: Viscoat #802 (TriPEA) (manufactured by Osaka Organic Chemical Industry Co., Ltd., 5-10 functional groups)

[0089] <Inorganic Oxide Particles (C)> ・C-1: Alumina particles (Manufactured by CHEM-MAT, product name "EN-2400l", average particle size 60 nm) ・C-2: Alumina particles (Manufactured by CIK Nanotech Co., Ltd., product name "ALMIBK15WT%-H06", average particle size 30 nm) ・C-3: Alumina particles (Manufactured by Denka Co., Ltd., product name "ASFP-20", average particle size 300 nm) ・C-4: Silica particles (Manufactured by CIK Nanotech Co., Ltd., product name "SRIMIBK15WT%-H65", average particle size 80 nm) ・C-5: Silica particles (Manufactured by CIK Nanotech Co., Ltd., product name "SRIMIBK15WT%-H58", average particle size 100 nm)

[0090] <(meth)acryloyl polymer (D)> ・D-1: (meth)acryloyl polymer obtained in Synthesis Example 6 (double bond equivalent 1,000 g / eq, weight-average molecular weight 30,000) ・D-2: (meth)acryloyl polymer obtained in Synthesis Example 7 (double bond equivalent 1,500 g / eq, weight-average molecular weight 24,000) ・D-3: (meth)acryloyl polymer obtained in Synthesis Example 8 (double bond equivalent 430 g / eq, weight-average molecular weight 28,000) ・D-4: (meth)acryloyl polymer obtained in Synthesis Example 9 (double bond equivalent 2,300 g / eq, weight-average molecular weight 26,000)

[0091] (Synthesis Example 6: Synthesis of D-1) In a reactor equipped with a stirrer, condenser, dropping funnel, and nitrogen inlet tube, 290.2 parts of butyl acetate were charged, and the temperature was raised while stirring until the system temperature reached 100°C. Then, a mixture of 75.0 parts of glycidyl methacrylate, 425.0 parts of methyl methacrylate, and 9.0 parts of t-butyl peroxy-2-ethylhexanoate was added dropwise from the dropping funnel over 3 hours, and the mixture was kept warm at 100°C under a nitrogen atmosphere for 10 hours. After the temperature was lowered to 60°C, 0.3 parts of methoquinone and 38.9 parts of acrylic acid were charged, followed by the addition of 2.8 parts of triphenylphosphine. The mixture was then heated to 110°C under air bubbling and held for 8 hours, after which it was further diluted with butyl acetate to obtain (meth)acryloyl polymer (D-1) with a resin solids content of 50%.

[0092] (Synthesis Example 7: Synthesis of D-2) In a reactor equipped with a stirrer, condenser, dropping funnel, and nitrogen inlet tube, 283.0 parts of butyl acetate were charged, and the temperature was raised while stirring until the system temperature reached 100°C. Then, a mixture of 50.0 parts of glycidyl methacrylate, 450.0 parts of methyl methacrylate, and 9.0 parts of t-butyl peroxy-2-ethylhexanoate was added dropwise from the dropping funnel over 3 hours, and the mixture was kept warm at 100°C under a nitrogen atmosphere for 10 hours. After the temperature was lowered to 60°C, 0.3 parts of methoquinone and 25.6 parts of acrylic acid were charged, followed by the addition of 2.7 parts of triphenylphosphine. The mixture was then heated to 110°C under air bubbling and held for 8 hours, after which it was further diluted with butyl acetate to obtain (meth)acryloyl polymer (D-2) with a resin solids content of 50%.

[0093] (Synthesis Example 8: Synthesis of D-3) In a reaction apparatus equipped with a stirrer, condenser, dropping funnel, and nitrogen inlet tube, 324.5 parts of butyl acetate were charged, and the temperature was raised while stirring until the system temperature reached 100°C. Then, a mixture of 200.0 parts of glycidyl methacrylate, 300.0 parts of methyl methacrylate, and 10.0 parts of t-butyl peroxy-2-ethylhexanoate was added dropwise from the dropping funnel over 3 hours, and the mixture was kept warm at 100°C under a nitrogen atmosphere for 10 hours. After the temperature was lowered to 60°C, 0.3 parts of methoquinone and 102.6 parts of acrylic acid were charged, followed by the addition of 3.1 parts of triphenylphosphine. The mixture was then heated to 110°C under air bubbling and held for 8 hours, after which it was further diluted with butyl acetate to obtain (meth)acryloyl polymer (D-3) with a resin solids content of 50%.

[0094] (Synthesis Example 9: Synthesis of D-4) In a reaction apparatus equipped with a stirrer, condenser, dropping funnel and nitrogen inlet tube, 287.2 parts of butyl acetate were charged, and the temperature was raised while stirring until the system temperature reached 100°C. Then, a mixture of 32.0 parts of glycidyl methacrylate, 468.0 parts of methyl methacrylate and 8.0 parts of t-butyl peroxy-2-ethylhexanoate was added dropwise from the dropping funnel over 3 hours, and the mixture was kept warm at 100°C under a nitrogen atmosphere for 10 hours. After the temperature was lowered to 60°C, 0.3 parts of methoquinone and 16.6 parts of acrylic acid were charged, followed by the addition of 2.5 parts of triphenylphosphine. The mixture was then heated to 110°C under air bubbling and held for 8 hours, after which it was further diluted with butyl acetate to obtain (meth)acryloyl polymer (D-4) with a resin solids content of 50%.

[0095] <Photopolymerization Initiator (E)> ・E-1: Omnirad 184 (manufactured by IGM Resins) ・E-2: Omnirad BP (manufactured by IGM Resins)

[0096] <Organic Solvents> ・PM: Propylene glycol monomethyl ether

[0097] <Other ingredients> ・Fluorine-based surfactant: Manufactured by Shin-Etsu Chemical Co., Ltd., product name "SHIN-ETSU SUBELLYN KY-1203" ・Radical scavenger (HALS): Manufactured by BASF, product name "Tinuvin 152"

[0098] [Examples 1-21, Comparative Examples 1-12] <Preparation of Paint Compositions> Paint compositions were obtained by mixing each raw material according to the formulations shown in Tables 1-6. In the tables, the amount (parts) of each raw material shown in the "Formulation" column is the total amount including non-solids. The content (%) of each component is the ratio of solids to the total mass of solids in the paint composition.

[0099] <Fabrication of Laminate> The obtained coating composition was applied using a D-bar to the PMMA layer side of a laminated film (manufactured by Mitsubishi Gas Chemical Co., Ltd., thickness 254 μm) consisting of a polymethyl methacrylate (PMMA) layer and a polycarbonate resin (PC) layer, so that the thickness of the coating film after drying would be 3.6 μm. The coating film was then dried in an 80°C dryer for 3 minutes to form the coating film. An electrodeless lamp (manufactured by Heraeus, lamp bulb: H bulb, 100% output) was used on the obtained coating film, and the integrated light amount at a wavelength of 365 nm was 300 mJ / cm². ２ By irradiating with ultraviolet light in such a manner, a cured coating film was formed, and a laminate was obtained.

[0100] <Evaluation> The following evaluations were performed on the obtained laminates. The results are shown in Tables 1 to 6.

[0101] (Evaluation of boiling adhesion) The obtained laminate was immersed in boiling water at 100°C for 1 hour, then the laminate was removed and the water droplets were wiped off. Then, in accordance with the cross-cut method of JIS K 5600-5-6:1999, a 10x10 grid was created on the coated surface at 1 mm intervals, and 24 mm wide cellophane tape (manufactured by Nichiban Co., Ltd.) was applied and peeled off. The boiling adhesion was evaluated according to the following evaluation criteria based on the number of squares in which the hardened coating remained: 5: 100 4: 95 or more and less than 100 3: 90 or more and less than 95 2: 80 or more and less than 90 1: less than 80

[0102] (Evaluation of weather-resistant adhesion) The obtained laminate was tested using an accelerated weathering tester (Q-LAB Corporation, product name "QUV / se") with UVB-313EL as the light source and an illuminance of 0.71 W / m². ３ After irradiation for 4 hours at a temperature of 60°C, the illuminance was 0 W / m². ３Condensation was performed for 4 hours at a temperature of 50°C. This operation was repeated for 500 hours. The water consumption during this period was 5 L / day. Subsequently, in accordance with the cross-cut method of JIS K 5600-5-6:1999, a 10x10 grid was created on the coated surface at 1 mm intervals, and 24 mm wide cellophane tape (manufactured by Nichiban Co., Ltd.) was applied and peeled off. The number of squares on which the hardened coating remained was used to evaluate the weather resistance and adhesion according to the following evaluation criteria: 5: 100, 4: 95 or more and less than 100, 3: 90 or more and less than 95, 2: 80 or more and less than 90, 1: less than 80.

[0103] (Evaluation of pencil hardness) The surface of the hardened coating film of the obtained laminate was tested in accordance with JIS K 5600-5-4:1999 using a pencil scratch hardness tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd., product name "No. 553-M") equipped with uni (manufactured by Mitsubishi Pencil Co., Ltd.) at a rate of 500 g / cm². ２ Scratch tests were conducted under the following conditions: load, scratch angle of 45 degrees, scratch distance of 7 mm. The hardness of the hardest pencil that showed no scratches was defined as the pencil hardness, and the pencil hardness was evaluated according to the following criteria: 5: H, 4: F, 3: HB, 2: B, 1: 2B

[0104] (Evaluation of scratch resistance) The surface of the hardened coating film of the obtained laminate was subjected to abrasion testing using a reciprocating abrasion tester (manufactured by HEIDON) at 500 g / cm². ２ A scratch test was conducted by rubbing the surface 1000 times back and forth with a No. 3 metal cloth (test attachment white cloth compliant with JIS L0803:2011) under a load, and the scratch resistance was evaluated according to the following evaluation criteria: 5: No scratches 4: No significant scratches in appearance 3: Scratches or gloss changes occurred on 1 / 4 to less than 1 / 2 of the test surface 2: Scratches or gloss changes occurred on 1 / 2 or more of the test surface 1: Significant scratches accompanied by abrasion or whitening of the coating occurred across the entire surface

[0105] (Evaluation of moldability) The obtained laminate was cut into pieces with a width of 15 mm and a length of 110 mm to prepare test specimens. Using a tensile testing machine (Shimadzu Corporation, product name "AGS-X"), a tensile test was performed on the test specimens under the conditions of a chuck distance of 60 mm, a temperature of 160°C, and a tensile strength of 50 mm / min. The chuck distance was measured when cracks appeared in the cured coating film, and the elongation was calculated using the formula 1 described above. The moldability was evaluated according to the following evaluation criteria. Note that the elongation when the chuck distance becomes 120 mm is defined as 100% elongation. 5: Elongation is 50% or more. 4: Elongation is 35% or more and less than 50%. 3: Elongation is 20% or more and less than 35%. 2: Elongation is 5% or more and less than 20%. 1: Elongation is less than 5%.

[0106] (Haze Evaluation) The surface of the hardened coating film of the obtained laminate was measured for haze (haze before scratch resistance evaluation) using a haze meter (manufactured by Murakami Color Technology Laboratory Co., Ltd., product name "HM-150") in accordance with JIS K 7136:2000. For the laminate after the scratch resistance evaluation described above, the haze (haze after scratch resistance evaluation) on the surface of the hardened coating film was measured in the same manner as above. The absolute value (ΔH) of the difference between the haze before scratch resistance evaluation and the haze after scratch resistance evaluation was calculated and evaluated according to the following evaluation criteria: 5: ΔH is less than 0.5% 4: ΔH is 0.5% or more and less than 0.8% 3: ΔH is 0.8% or more and less than 1.2% 2: ΔH is 1.2% or more and less than 1.6% 1: ΔH is 1.6% or more

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113] When the paint compositions of Examples 1 to 21 were used, the boiling adhesion, weather-resistant adhesion, pencil hardness, scratch resistance, moldability, and haze ratings were 3 or higher. On the other hand, when the paint compositions of Comparative Examples 1 to 12, which did not satisfy any of the components of Claim 1, were used, the weather-resistant adhesion, pencil hardness, scratch resistance, moldability, and haze ratings were 2 or lower.

[0114] [Application Example] On the PC side of the laminate obtained in Example 1, opposite to the cured coating side, i.e., the PC side of the laminate film (manufactured by Mitsubishi Gas Chemical Co., Ltd., 254 μm thick), a color ink containing polyurethane resin and vinyl chloride-vinyl acetate copolymer as a binder resin, carbon black as a coloring agent, and a polyisocyanate compound as a curing agent was applied using a D-bar to a coating thickness of 1 μm after drying, dried with a dryer for 10 seconds, and then aged at 40°C for 48 hours to form an ink layer. Next, an adhesive containing thermoplastic acrylic resin was applied on the surface of the ink layer using a D-bar to a coating thickness of 2 μm after drying, and dried with a dryer for 30 seconds to form an adhesive layer and obtain a decorative sheet. The obtained decorative sheet was confirmed to have excellent pencil hardness, scratch resistance, and haze properties, and it was confirmed that there were no problems with its use. Subsequently, the adhesive layer of the obtained decorative sheet was superimposed onto a curved ABS molded body (the molded body to be decorated), and the two were bonded together by vacuum forming at 150°C for 30 seconds to obtain a decorated molded body. Since vacuum forming was performed without problems on the curved ABS molded body, it was confirmed that the decorative sheet has excellent moldability. Furthermore, when the boiling adhesion of the obtained decorated molded body was evaluated in the same manner as above, the score was 5 or higher, confirming that the decorated molded body has excellent boiling adhesion.

[0115] The paint composition of the present invention can form a cured coating film with excellent hardness and moldability, and is useful as a paint composition for decorative sheets.

Claims

1. An active energy ray curable coating composition comprising: a urethane (meth)acrylate resin (A); a (meth)acryloyl group-containing monomer (B) (excluding fluorine-based surfactants); and inorganic oxide particles (C), wherein the urethane (meth)acrylate resin (A) contains a structure based on isophorone diisocyanate, the number of (meth)acryloyl groups contained in the molecule of the urethane (meth)acrylate resin (A) is 4 to 12, the weight-average molecular weight is 5,000 to 80,000, and the amount of urethane bond is 3.0 × 10 －３ ~5.6 x 10 －３ A paint composition wherein the concentration is eq / g, and the (meth)acryloyl group-containing monomer (B) contains a monofunctional monomer (B1) containing one (meth)acryloyl group in its molecule and a polyfunctional monomer (B2) containing three to ten (meth)acryloyl groups in its molecule, the glass transition temperature of the homopolymer of the monofunctional monomer (B1) is 90 to 160°C, the mass ratio of the monofunctional monomer (B1) to the polyfunctional monomer (B2) in terms of solid content is 0.3 to 1.2, the average particle size of the inorganic oxide particles (C) is 90 nm or less, and the content of the urethane (meth)acrylate resin (A) in terms of solid content is 65.0 to 85.0% by mass relative to the total mass of solid content of the paint composition.

2. The paint composition according to claim 1, wherein the content of the (meth)acryloyl group-containing monomer (B) on a solid content basis is 5.0 to 16.0% by mass with respect to the total mass of solids of the paint composition.

3. The paint composition according to claim 1, wherein the urethane (meth)acrylate resin (A) is a reaction product of a polyisocyanate compound containing at least isophorone diisocyanate, a polyol compound, and a monomer containing a hydroxyl group and a (meth)acryloyl group, and contains a structure based on the polyisocyanate compound, a structure based on the polyol compound, and a structure based on the monomer containing the hydroxyl group and a (meth)acryloyl group, and the ratio of the structure based on isophorone diisocyanate to the total mass of the structure based on the polyisocyanate compound is 50% by mass or more.

4. The paint composition according to claim 1, wherein the inorganic oxide particles (C) are at least one selected from the group consisting of alumina particles and silica particles.

5. The paint composition according to claim 1, wherein the content of the inorganic oxide particles (C) on a solid content basis is 3.0 to 14.0% by mass relative to the total mass of solid content of the paint composition.

6. The paint composition according to claim 1, further comprising (meth)acryloyl polymer (D), wherein the double bond equivalent of the (meth)acryloyl polymer (D) is 500 to 2000 g / eq.

7. The paint composition according to claim 6, wherein the content of the (meth)acryloyl polymer (D) on a solid content basis is 1.0 to 6.0% by mass with respect to the total mass of solids of the paint composition.

8. The coating composition according to claim 1, wherein the elongation of a laminate prepared by the following method is 50% or more, as determined by the following measurement method. [Method for preparing a laminate] A coating composition is applied to the surface of the polymethyl methacrylate layer of a 254 μm thick laminated film, in which a polymethyl methacrylate layer and a polycarbonate layer are laminated in this order, so that the thickness of the coating film after drying is 3.6 μm, and the coating film is dried at 80°C for 3 minutes. The obtained coating film is then subjected to an integrated light amount of 300 mJ / cm² at a wavelength of 365 nm. ２ A cured coating film is formed by irradiating the laminated film with ultraviolet light in such a manner, and a laminate of the laminated film and the cured coating film is obtained. [Method for measuring elongation] A test piece with a width of 15 mm and a length of 110 mm is cut from the laminate, and a tensile test is performed under the conditions of a chuck distance of 60 mm, a temperature of 160°C, and a tensile strength of 50 mm / min. The chuck distance at the time when a crack occurs in the cured coating film of the laminate is measured, and the elongation is calculated using the following formula 1. Elongation = (x2 - x1) / x1 × 100 ...Formula 1 Here, x1 represents the chuck distance before the tensile test (60 mm), and x2 represents the chuck distance at the time when a crack occurs.

9. A laminate comprising a plastic film and a cured coating film of a coating composition according to any one of claims 1 to 8, formed on at least one surface of the plastic film.

10. A decorative sheet comprising the laminate described in claim 9.

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