Curable resin sheet, vehicle and vehicle component, and manufacturing method of vehicle and vehicle component

Abstract

To provide a curable resin sheet in which at least either of adhesive force or peeling force is good, and the adhesive force or the peeling force is less likely to change with time.SOLUTION: A curable resin sheet includes at least one resin layer composed of a curable resin composition containing a (meth)acrylic resin and block isocyanate, wherein at least the one resin layer is composed of a curable resin composition which has a functional group reactive with isocyanate, and further contains a synthetic resin that is a resin other than the (meth)acrylic resin, and the molecular weight of the synthetic resin is 1,000 or more and 5,000 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable resin sheet, a vehicle and a vehicle part coated with the sheet, and a method for manufacturing the vehicle and the vehicle part. [Background technology]

[0002] Furniture, steel plates, vehicle bodies, and the like are coated with exterior paint for the sake of design and durability. Exterior coating is known to be performed using films, such as decorative films, and various types of decorative films have been developed for such applications. For example, Patent Document 1 discloses a thermosetting coating sheet that is in an uncured or semi-cured state and can retain its sheet shape, and that contains as its main components an acrylic resin, a monomer having multiple functional groups as a crosslinking agent that reacts with isocyanate groups, and a blocked isocyanate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 2688105 Summary of the Invention [Problem to be solved by the invention]

[0004] The resin layer constituting the decorative film needs to have a certain level of adhesive strength to attach it to an adherend or a certain level of peel strength from the transfer layer to maintain transportability. Therefore, adding a plastic resin to enhance the adhesive strength or peel strength has been investigated. However, even if a plastic resin is used, it may not be possible to impart sufficient adhesive strength or peel strength to the decorative film. Furthermore, the adhesive strength or peel strength may change due to bleeding out of the plastic resin over time, making it impossible to impart appropriate adhesive strength or peel strength to the decorative film.

[0005] Therefore, an object of the present invention is to provide a curable resin sheet that has good adhesive strength and / or peel strength, and that is less likely to change in adhesive strength or peel strength over time. [Means for solving the problem]

[0006] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by making at least one of the resin layers constituting the curable resin sheet from a curable resin composition containing a synthetic resin having a molecular weight within a certain range. That is, the present invention provides the following [1] to

[12] .

[0007] [1] A curable resin sheet comprising at least one resin layer made of a curable resin composition containing a (meth)acrylic resin and a blocked isocyanate, wherein at least one of the resin layers is made of a curable resin composition having a functional group that reacts with isocyanate and further containing a synthetic resin that is a resin other than a (meth)acrylic resin, and the molecular weight of the synthetic resin is 1,000 or more and 5,000 or less. [2] The curable resin sheet according to [1], which comprises two or more of the resin layers. [3] The curable resin sheet according to [2], wherein the resin layer comprises a colored layer and a clear layer. [4] The curable resin sheet according to any one of [1] to [3], further comprising a transfer layer. [5] The curable resin sheet according to any one of [1] to [4], wherein the synthetic resin has at least one functional group selected from the group consisting of a hydroxyl group, an amino group, an isocyanate group, and a carboxyl group. [6] The curable resin sheet according to any one of [1] to [5], wherein the synthetic resin has a glass transition temperature of 60° C. or lower. [7] The curable resin sheet according to any one of [1] to [6], wherein the content of the synthetic resin is 40 mass % or less based on the total amount of the (meth)acrylic resin and the synthetic resin. [8] The curable resin sheet according to any one of [1] to [7], wherein the (meth)acrylic resin has a plurality of functional groups and contains a (meth)acrylic resin having a weight average molecular weight of 50,000 or more and 1,000,000 or less. [9] A vehicle painted using the curable resin sheet according to any one of [1] to [8].

[10] A vehicle part coated with the curable resin sheet according to any one of [1] to [8].

[11] A method for manufacturing a vehicle, comprising a step of painting using the curable resin sheet according to any one of [1] to [8].

[12] A method for producing a vehicle part, comprising a step of painting using the curable resin sheet according to any one of [1] to [8]. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a curable resin sheet that has good adhesive strength and / or peel strength, and in which the adhesive strength or peel strength is unlikely to change over time. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a curable resin sheet. [Figure 2] FIG. 1 is a schematic cross-sectional view showing an example of a curable resin sheet. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Hardening resin sheet] (resin layer) The curable resin sheet of the present invention has one or more resin layers made of a curable resin composition containing a (meth)acrylic resin and a blocked isocyanate. At least one of the resin layers constituting the curable resin sheet is made of a curable resin composition further containing a synthetic resin. That is, when the resin layer has a multilayer structure described below, at least one of the layers may be made of a curable resin composition containing a (meth)acrylic resin, a blocked isocyanate, and a synthetic resin, or a resin layer may be provided that is made of a curable resin composition that contains a (meth)acrylic resin and a blocked isocyanate but no synthetic resin. Also, when the resin layer has a single-layer structure, the resin layer may be made of a curable resin composition that contains a (meth)acrylic resin, a blocked isocyanate, and a synthetic resin. In the following description, a curable resin composition containing a synthetic resin will be referred to as a curable resin composition (X), and a curable resin composition not containing a synthetic resin will be referred to as a curable resin composition (Y). A layer made of the curable resin composition (X) will be referred to as a synthetic resin-containing layer, and a layer made of the curable resin composition (Y) will be referred to as a synthetic resin-free layer. When describing matters common to the curable resin composition (X) and the curable resin composition (Y), they may be simply referred to as curable resin compositions.

[0011] <<Curable resin composition (X)>> <Synthetic resin> The synthetic resin used in the curable resin composition (X) has a functional group reactive with isocyanate, is a resin other than a (meth)acrylic resin, and has a molecular weight of 1000 or more and 5000 or less. If the molecular weight of the synthetic resin is less than 1000, the synthetic resin may bleed out from the curable resin sheet over time, causing a change in the adhesive strength or peel strength of the curable resin sheet. If the molecular weight of the synthetic resin exceeds 5000, the adhesive strength and peel strength of the curable resin sheet may not be satisfactory. From these viewpoints, the molecular weight of the synthetic resin is preferably 1000 or more and 4500 or less, and more preferably 1020 or more and 2500 or less. The molecular weight of the synthetic resin can be measured by GPC and is a number average molecular weight.

[0012] As described above, the synthetic resin preferably has a functional group that reacts with isocyanate and is used as a curable resin. When the synthetic resin has the functional group, the functional group reacts with the isocyanate group of the blocked isocyanate when the curable resin sheet is baked, thereby improving the adhesiveness to the adherend. The functional group preferably has at least one functional group selected from a hydroxyl group, an amino group, an isocyanate group, and a carboxyl group, more preferably at least one selected from a hydroxyl group and an amino group, and even more preferably a hydroxyl group.

[0013] As described above, the synthetic resin used in the present invention is a resin other than a (meth)acrylic resin. By using a resin other than a (meth)acrylic resin as the synthetic resin, the synthetic resin and the (meth)acrylic resin as the main component are not too miscible with each other, and the synthetic resin moderately aggregates, thereby imparting good adhesive strength to the curable resin sheet. Specific examples of synthetic resins include, but are not limited to, polyester resins, polycarbonate resins, polyether resins, vinyl chloride-vinyl acetate copolymer resins, polyalkyleneimines, polybutadiene resins, and the like.

[0014] Examples of polyester-based resins include polyester polyols obtained by reacting polycarboxylic acids such as dibasic acids with polyols such as diols. Examples of dibasic acids include divalent aromatic carboxylic acids such as terephthalic acid, isophthalic acid, 1,5-naphthalic acid, and 2,6-naphthalic acid, and divalent aliphatic carboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. Examples of diols include linear aliphatic diols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, and diethylene glycol, branched aliphatic diols such as neopentyl glycol, and cyclic aliphatic diols such as cyclohexanediol. Polyalkyd resins may also be used as polyester-based resins. The polyester resin may be a polycaprolactone resin. The polycaprolactone resin may be poly-ε-caprolactone polyol obtained by ring-opening polymerization of ε-caprolactone. The polyester resin is preferably a polyester diol.

[0015] The polycarbonate resin may have a structure in which structural units derived from a polyhydroxy compound are linked by carbonate bonds. The polyhydroxy compound is generally a dihydroxy compound. The polyhydroxy compound may be any of a linear aliphatic polyol, an aliphatic polyol having a branched structure, an alicyclic polyol having an alicyclic structure, and an aromatic polyhydroxy compound, but an aliphatic polyol having a linear or branched structure is preferred. The dihydroxy compound has, for example, 4 to 16 carbon atoms, preferably 5 to 12 carbon atoms. The polycarbonate resin is preferably a polycarbonate diol.

[0016] The polyether resin may be any resin having a polyether skeleton. Examples of the polyether skeleton include those derived from polyoxyalkylene glycol. Specific examples of preferred polyoxyalkylene glycols include polypropylene glycol, polytetramethylene ether glycol, and copolymer polyether glycol of propylene oxide and tetrahydrofuran. Among these, polytetramethylene ether glycol (PTMG) is more preferred. The polyether resin is preferably a polyether polycarbonate having a polyether skeleton and a carbonate bond. The polyether polycarbonate polyol preferably has a structure in which a plurality of polyether skeletons are bonded via carbonate bonds. The polyether polycarbonate polyol is preferably a polyether polycarbonate diol containing two hydroxyl groups per molecule. The polyether polycarbonate diol preferably has hydroxyl groups at both ends of the molecule.

[0017] Vinyl chloride-vinyl acetate copolymer resin is a resin made by copolymerizing vinyl chloride and vinyl acetate. It is preferable that the vinyl chloride-vinyl acetate copolymer resin contains hydroxyl groups, for example, hydroxyl groups derived from the vinyl alcohol structure. Examples of polyalkyleneimines include polyethyleneimine and polypropyleneimine, and polyethyleneimine is more preferred. Polyethyleneimine is obtained by polymerizing ethyleneimine and has a branched chain structure containing primary, secondary, and tertiary amine nitrogen atoms.

[0018] Of the above, from the viewpoints of adhesive strength, peel strength, and the rate of change in adhesive strength or peel strength over time, at least one selected from polyester-based resins, polycarbonate-based resins, polyether-based resins, and polyethyleneimine-based resins is preferred, and of these, polyester-based resins, polycarbonate-based resins, and polyether-based resins are more preferred, with polyester-based resins being even more preferred. The synthetic resins may be used alone or in combination of two or more.

[0019] As the synthetic resin, commercially available products may be used, specific examples of which include "Burnoc D-161" manufactured by DIC Corporation, "P-4010" manufactured by Kuraray Co., Ltd., "Placcel 410" manufactured by Daicel Corporation, "ALLP" manufactured by Nissin Chemical Industry Co., Ltd., "PH100" manufactured by UBE Corporation, "NT2002" manufactured by Mitsubishi Chemical Corporation, and "SP-018" manufactured by Nippon Shokubai Co., Ltd.

[0020] The synthetic resin may or may not have a glass transition temperature (Tg). When the synthetic resin has a glass transition temperature, the glass transition temperature may be, for example, 80°C or lower, preferably 60°C or lower, more preferably 30°C or lower, and even more preferably 0°C or lower. When the glass transition temperature of the synthetic resin is equal to or lower than the upper limit, at least one of the adhesive strength and peel strength of the curable resin sheet is easily improved. On the other hand, the glass transition temperature of the synthetic resin is not particularly limited, but from the viewpoint of easily imparting appropriate tackiness to the resin layer, it is preferably -90°C or higher, more preferably -85°C or higher, and even more preferably -75°C or higher. In this specification, the glass transition temperature is a value determined by differential scanning calorimetry (DSC) in accordance with JIS K 7121.

[0021] When the synthetic resin has hydroxyl groups, the hydroxyl value of the synthetic resin is not particularly limited, but is preferably 10 mgKOH / g or more, more preferably 20 mgKOH / g or more, and even more preferably 50 mgKOH / g or more. It is also preferably 300 mgKOH / g or less, more preferably 250 mgKOH / g or less, and even more preferably 230 mgKOH / g or less. By setting the hydroxyl value within the above range, curability is improved, and it becomes easier to achieve high hardness in the resin layer after curing. In this specification, the hydroxyl value can be measured in accordance with JISK 1557-1:2007.

[0022] The content of the synthetic resin in the curable resin composition (X) may be, for example, 60% by mass or less, preferably 50% by mass or less, and more preferably 40% by mass or less, based on the total combined amount of the (meth)acrylic resin and the synthetic resin. Having the synthetic resin content at or below the upper limit makes it easier to improve the rate of change in adhesive strength or peel strength of the curable resin sheet over time. On the other hand, the content of the synthetic resin is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total combined amount of the (meth)acrylic resin and the synthetic resin. By having the synthetic resin content at or above the lower limit, good adhesive strength is imparted to the curable resin sheet, making it difficult for the curable resin sheet to be easily peeled from the adherend. Also, good peel strength is imparted to the curable resin sheet, making it difficult for the transfer layer, described below, to be unintentionally peeled off, for example, when the curable resin sheet includes a transfer layer. Although the curable resin composition (X) may be diluted with a volatile component such as a solvent as described below, the content (mass%) of each component in the curable resin composition (X) herein refers to a value based on the solid content excluding volatile components. The same applies to the content (mass%) of each component in the curable resin composition (Y) described below.

[0023] <(Meth)acrylic resin> The (meth)acrylic resin contained in the curable resin composition (X) may be contained as a curable resin. Examples of the (meth)acrylic resin include (meth)acrylic resins having a plurality of functional groups. The functional group may be any functional group that reacts with isocyanate, and specific examples include a hydroxyl group, a carboxyl group, and an amino group. Among these, a hydroxyl group is preferred. The (meth)acrylic resin may have only one type of functional group, or may have two or more types. Among these, it is preferred that the (meth)acrylic resin has a hydroxyl group. Therefore, the (meth)acrylic resin is preferably a (meth)acrylic polyol having a plurality of hydroxyl groups.

[0024] The (meth)acrylic resin is preferably an acrylic polymer obtained by polymerizing a monomer mixture containing a (meth)acrylic acid ester monomer and a functional group-containing monomer having the above-mentioned functional group, such as a hydroxyl group, an amino group, or a carboxyl group. Such an acrylic polymer can contain functional groups in the acrylic polymer by using the functional group-containing monomer. The monomer mixture may also contain monomers other than the (meth)acrylic acid ester monomer and the functional group-containing monomer, such as a styrene derivative monomer. Note that (meth)acrylic refers to either methacrylic or acrylic, and the same applies to other similar terms.

[0025] Examples of the (meth)acrylic acid ester monomer include (meth)acrylic acid ester monomers that do not have the above-mentioned functional groups, such as alkyl (meth)acrylates having an alkyl group with about 1 to 18 carbon atoms, (meth)acrylates having an aromatic ring such as benzyl (meth)acrylate and phenoxydiethylene glycol (meth)acrylate, and 2-ethoxyethyl (meth)acrylate. Examples of functional group-containing monomers include (meth)acrylic acid ester monomers having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, (meth)acrylic acid ester monomers having an amino group such as 2-aminoethyl (meth)acrylate, and monomers having a carboxyl group such as (meth)acrylic acid. Furthermore, as the (meth)acrylic resin, a copolymer obtained by block or graft polymerization of the above-mentioned acrylic polymer with other monomers or polymers may be used.

[0026] The curable resin composition (X) constituting the synthetic resin-containing layer preferably contains, as the (meth)acrylic resin, a (meth)acrylic resin (hereinafter also referred to as (meth)acrylic resin (A)) that is solid and has a weight-average molecular weight (Mw) of 50,000 or more and 1,000,000 or less, and that has multiple functional groups. The (meth)acrylic resin (A) has a weight-average molecular weight within the above range and is solid, which makes it easier to maintain the resin layer in a consistent shape even before curing, making it easier to properly form the resin layer on, for example, a transfer layer. It also makes it easier to impart tackiness and extensibility to the resin layer. The tackiness and extensibility of the resin layer improve vacuum moldability, preventing breakage during vacuum molding or the like. Furthermore, a weight-average molecular weight within the above range makes it easier to increase the hardness of the resin layer after curing. From the above viewpoints, the weight average molecular weight of the (meth)acrylic resin (A) is preferably 150,000 or more, more preferably 180,000 or more, and preferably 500,000 or less, more preferably 450,000 or less. In this specification, the weight average molecular weight (Mw) is measured by gel permeation chromatography (GPC) and is calculated as a value converted into standard polystyrene. Furthermore, being solid means being solid at room temperature (23°C) and normal pressure (1 atm).

[0027] The glass transition temperature (Tg) of the (meth)acrylic resin (A) is preferably less than 90° C., more preferably not more than 80° C., even more preferably not more than 60° C., and preferably not less than 0° C., more preferably not less than 10° C. When the glass transition temperature of the (meth)acrylic resin (A) is within the above range, it becomes easier to impart a certain level of tackiness and extensibility to the resin layer.

[0028] The (meth)acrylic resin (A) is preferably a (meth)acrylic polyol having a plurality of hydroxyl groups (hereinafter also referred to as (meth)acrylic polyol (A')). As described above, the (meth)acrylic polyol (A') can be obtained, for example, by polymerizing a monomer mixture containing a (meth)acrylic acid ester monomer and a hydroxyl group-containing monomer. The hydroxyl value of the (meth)acrylic polyol (A') is preferably 20 mgKOH / g or more and 200 mgKOH / g or less, more preferably 30 mgKOH / g or more and 150 mgKOH / g or less. By setting the hydroxyl value within the above range, the curability is improved, and it becomes easier to achieve high hardness of the resin layer after curing.

[0029] The content of the (meth)acrylic resin (A) in the curable resin composition (X) constituting the synthetic resin layer is not particularly limited, but is preferably 10% by mass or more and 80% by mass or less, more preferably 15% by mass or more and 75% by mass or less, and even more preferably 25% by mass or more and 65% by mass or less, based on the total amount of the curable resin composition (X). By setting the content of the (meth)acrylic resin (A) within the above range, the coatability and curability of the resin layer can be easily improved. In the curable resin composition (X), the (meth)acrylic resin (A) may be used alone or in combination of two or more kinds.

[0030] The curable resin composition (X) may contain, as a curable resin, in addition to the (meth)acrylic resin (A) described above, a (meth)acrylic resin having a weight average molecular weight of less than 50,000 (hereinafter also referred to as (meth)acrylic resin (c)). The (meth)acrylic resin (c) is preferably one that is compatible with the high molecular weight (meth)acrylic resin (A) and has a thermosetting functional group. Examples of the (meth)acrylic resin (c) include (meth)acrylic polymers having functional groups such as hydroxyl groups, amino groups, and carboxyl groups, and among these, (meth)acrylic polymers having hydroxyl groups are preferred. Poly(meth)acrylates having carboxyl groups are also preferred. The weight average molecular weight of the (meth)acrylic resin (c) is preferably 400 or more and 30,000 or less, more preferably 450 or more and 20,000 or less, and even more preferably 450 or more and 5,000 or less. Moreover, the (meth)acrylic resin (c) is preferably a liquid at room temperature and normal pressure.

[0031] The curable resin composition (X) may or may not contain the (meth)acrylic resin (c). When the (meth)acrylic resin (c) is contained, its content is not particularly limited, but is, for example, 0 to 0.5, preferably 0.01 to 0.3, more preferably 0.03 to 0.1, in mass ratio relative to the content of the (meth)acrylic resin (A).

[0032] <Blocked isocyanate> The blocked isocyanate contained in the curable resin composition (X) may be contained as a curing agent. The blocked isocyanate is a compound in which an isocyanate group is blocked with a protecting group. When exposed to high temperatures, the protecting group (blocking agent) is thermally dissociated and removed, causing a curing reaction between the resulting isocyanate group and the functional group in the curable resin (typically, a hydroxyl group of a polyol). A blocked isocyanate can be obtained, for example, by reacting an isocyanate compound having two or more isocyanate groups in one molecule with a blocking agent.

[0033] The isocyanate compound having two or more isocyanate groups in one molecule is not particularly limited, and examples thereof include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isocyanurate group-containing isocyanate compounds, and modified products thereof. Among these, at least one selected from an isocyanurate modified product of hexamethylene diisocyanate and an isocyanurate modified product of an isocyanurate group-containing isocyanate compound is preferred, and an isocyanurate modified product of hexamethylene diisocyanate is more preferred.

[0034] Examples of blocking agents include pyrazoles, phenols, oximes, lactams, and active methylenes. The content of the blocked isocyanate in the curable resin composition (X) may be adjusted so that the ratio of the number of functional groups in the curable resin to the number of isocyanate groups in the blocked isocyanate (number of functional groups / number of isocyanate groups) is preferably 0.4 or more and 1.8 or less, more preferably 0.6 or more and 1.5 or less.

[0035] <Other ingredients> The curable resin composition (X) may contain appropriate components other than the curable resin ((meth)acrylic resin and synthetic resin) and the curing agent. For example, when the curable resin sheet is used for coating applications, it is preferable to appropriately contain components according to the performance required for the coating formed from the resin layer. For example, when the coating formed from the resin layer is to be a colored coating, it is preferable to add a colorant such as a pigment, dye, or luster material to make the resin layer a colored layer. Furthermore, when the coating formed from the resin layer is to be a heat-shielding coating, it is preferable to add a heat-shielding material to the curable resin composition (X) to make the resin layer a heat-shielding layer. The resin layer may also contain components other than those described above, such as additives other than those described above, such as crosslinking agents, dispersants, inorganic fillers other than pigments and luster materials, antioxidants, antioxidants, and rust inhibitors. Furthermore, the resin layer may be made of a clear layer, which will be described later. Among these, it is preferable that the resin layer contains at least a colorant.

[0036] Examples of pigments used in the colorant include, but are not limited to, metal oxide pigments such as titanium oxide and iron oxide; inorganic pigments such as carbon black, clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, talc, silica, and alumina white; and organic pigments such as azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, perylene pigments, perinone pigments, benzimidazolone pigments, vat pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, indanthrone pigments, dioxane pigments, and indigo pigments. As the dye, known dyes can be used, and examples thereof include azo dyes, anthraquinone dyes, indigoid dyes, and stilbene dyes. The lustrous material is a compound that can impart lustrous properties to the resin layer and can impart the property of exhibiting gloss when observed from multiple directions. Examples of the lustrous material include, but are not limited to, compounds in which a titanium oxide layer is provided on the surface of natural mica, synthetic mica, alumina flakes, glass flakes, etc. The resin layer preferably contains at least one of a pigment or a luster material as a colorant, and more preferably contains a pigment. The resin layer also preferably contains both a pigment and a luster material.

[0037] The content of the colorant in the curable resin composition (X) that forms the resin layer is not particularly limited, but is, for example, about 0.1 to 25 mass %, preferably 0.3 to 20 mass %, and more preferably 0.5 to 12 mass %. In addition to the above-mentioned additives such as the colorant and the heat-shielding material, the curable resin composition (X) may appropriately contain additives such as an inorganic filler, a catalyst such as a urethanization catalyst, a curing accelerator, a surface conditioner, an antifoaming agent, a crosslinking agent, a dispersant, an antioxidant, an antioxidant, and an ultraviolet absorber.

[0038] <<Curable resin composition (Y)>> As described above, the resin layer may include a synthetic resin-free layer made of a curable resin composition (Y) that does not contain a synthetic resin. The curable resin composition (Y) contains at least a (meth)acrylic resin and a blocked isocyanate. The curable resin composition (Y) may also contain components other than the (meth)acrylic resin and the blocked isocyanate (other components) as appropriate. The content of the (meth)acrylic resin in the curable resin composition (Y) is not particularly limited, but is preferably 30% by mass or more and 90% by mass or less, more preferably 40% by mass or more and 80% by mass or less, and even more preferably 45% by mass or more and 75% by mass or less, based on the total amount of the curable resin composition (Y). By setting the content of the (meth)acrylic resin within the above range, it becomes easier to improve the coatability and curability of the resin layer. In the curable resin composition (Y), the (meth)acrylic resin may be used alone or in combination of two or more kinds. The (meth)acrylic resin, blocked isocyanate, and other components in the curable resin composition (Y) are as described for the curable resin composition (X), and therefore will not be described here in detail.

[0039] <<Resin layer structure>> The resin layer may have a single-layer structure consisting of a single layer, or may have a multi-layer structure consisting of two or more layers, but a multi-layer structure is preferable. The multi-layer structure allows, for example, various functions to be imparted to the coating formed from the resin layer. In the case of a multilayer resin layer, each layer may be made of the curable resin composition described above. Each layer may contain a colorant as described above to form a colored layer, a heat-shielding material to form a heat-shielding layer, or a clear layer that does not substantially contain a colorant.

[0040] In the case of a multi-layer structure, the resin layer preferably has at least a colored layer and a clear layer. When the resin layer has a colored layer and a clear layer and a transfer layer (described later) is provided, the clear layer and the colored layer are preferably arranged in this order from the transfer layer side. With this structure, when the curable resin sheet is attached to an adherend, the colored layer and the clear layer are arranged in this order from the adherend side. By having a colored layer, the resin layer can color the adherend with the coating formed by the resin layer. Furthermore, by providing a clear layer in addition to the colored layer, the colored layer can be protected and glossy. The colored layer preferably contains a pigment as a colorant, and therefore, it is particularly preferable that the resin layer has a clear layer and a colored layer.

[0041] The colored layer and the clear layer may be made of the curable resin composition (X) or the curable resin composition (Y), and the curable resin composition for the colored layer may contain a colorant as described above. On the other hand, the clear layer is a transparent layer and only needs to have a transparency sufficient to allow the color of the colored layer to be visible from the outside through the clear layer, for example, a transmittance of 80% or more for light with a wavelength of 450 nm. The clear layer is preferably a resin layer that does not contain a colorant, but may contain a small amount of colorant as long as it does not impair its function. The content of the colorant in the specific curable resin composition for the clear layer may be, for example, about 1% by mass or less, preferably about 0.5% by mass or less, and more preferably about 0.1% by mass or less.

[0042] Of course, when the resin layer has a multi-layer structure, it is not limited to a two-layer structure of a clear layer and a colored layer, and various laminate structures are possible. A three-layer or more structure may be formed by providing two or more colored layers and one or more clear layers, or the clear layer may be omitted and the structure may consist of two colored layers. Also, two or more clear layers may be provided. Furthermore, a three-layer or more structure may be formed by providing a heat-shielding layer or the like between the clear layer and the colored layer.

[0043] Furthermore, when the resin layer has a multi-layer structure, as described above, it is sufficient that it has at least one synthetic resin-containing layer, and it may also have a synthetic resin-free layer, or all layers may be synthetic resin-containing layers. When synthetic resin-free layers are provided, the synthetic resin-containing layers may be in contact with each other, or the synthetic resin-free layers may be in contact with each other, or a synthetic resin-containing layer may be in contact with a synthetic resin-free layer. When at least one of the synthetic resin-containing layer and the synthetic resin-free layer is two or more layers, the synthetic resin-containing layers or the synthetic resin-free layers do not need to be in contact with each other. For example, the structure may be synthetic resin-containing layer / synthetic resin-free layer / synthetic resin-containing layer, or synthetic resin-free layer / synthetic resin-containing layer / synthetic resin-free layer. Furthermore, the layer in contact with the adherend may be a synthetic resin-containing layer or a synthetic resin-free layer. Furthermore, when the curable resin sheet has a transfer layer, the layer in contact with the transfer layer may also be a synthetic resin-containing layer or a synthetic resin-free layer. However, it is preferable that the outermost layer of the multiple resin layers (i.e., either the layer in contact with the adherend or the layer in contact with the transfer layer) is a synthetic resin-containing layer.

[0044] When the resin layer has a colored layer and a clear layer, either the colored layer or the clear layer may be a synthetic resin-containing layer, or both the colored layer and the clear layer may be synthetic resin-containing layers. When the colored layer is a synthetic resin-containing layer, it is possible to impart good adhesive strength to the colored layer. Furthermore, when the clear layer is a synthetic resin-containing layer, it is possible to impart good peel strength to the clear layer. For example, when the curable resin sheet has a transfer layer, it is possible to prevent the transfer layer in contact with the clear layer from unintentionally peeling off.

[0045] Furthermore, when the resin layer has a structure of three or more layers, only the outermost layer may be a synthetic resin-containing layer, only layers other than the outermost layer (hereinafter also referred to as "middle layers") may be synthetic resin-containing layers, or both the outermost layer and the middle layer may be synthetic resin-containing layers. When the middle layer is a synthetic resin-containing layer, the adhesive strength between the middle layer and the layer in contact with it can be improved, and when the curable resin sheet is attached to an adherend, the appearance of the adherend can be maintained good.

[0046] The thickness of the resin layer is not particularly limited, but is, for example, 20 μm or more and 200 μm or less, and preferably 30 μm or more and 100 μm or less. When a colored layer and a clear layer are provided on the resin layer, the thickness of the colored layer is not particularly limited, but is, for example, 10 μm to 100 μm, preferably 15 μm to 50 μm. The thickness of the clear layer is not particularly limited, but is, for example, 10 μm to 100 μm, preferably 15 μm to 50 μm.

[0047] (transfer layer) The curable resin sheet of the present invention may include at least a resin layer, but preferably further includes a transfer layer. When including a transfer layer, for example, as shown in Fig. 1, the curable resin sheet 10 may include a transfer layer 12 and a resin layer 11 laminated on one side of the transfer layer 12. Note that Fig. 1 shows a structure in which the resin layer 11 is a single layer, but two or more resin layers may be laminated on the transfer layer 12. The transfer layer is a member that protects the resin layer from scratches and foreign matter adhesion, and also serves as a support when the resin layer is attached to an adherend. The transfer layer is preferably formed from a resin film. The resin used for the resin film may be, for example, a thermoplastic resin. Specific examples of resins used in resin films include cyclic polyolefin resins, polyolefin resins, polyester resins such as polybutylene terephthalate (PBT) and polyethylene terephthalate (PET), polyamide resins, polycarbonate resins, acrylic resins, fluororesins, vinyl chloride resins (PVC) such as soft vinyl chloride resins, polymethylpentene resins, tetrafluoroethylene resins, and acrylonitrile-butadiene-styrene copolymer (ABS) resins. Cyclic polyolefin resins are polymers containing structural units derived from cyclic olefins. Polyolefin resins are polyolefin resins other than cyclic polyolefin resins, specifically polypropylene resin (PP) and polyethylene resin (PE). Polyethylene resins include low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene (LLDPE). These resins can be used alone or in combination of two or more. Among these resins, cyclic olefin resins, PET, PBT, PVC, ABS, PE, and PP are preferred from the viewpoints of vacuum moldability and transferability.

[0048] The transfer layer may have at least one surface that has been release-treated with a release agent such as a silicone-based release agent or a fluorine-based release agent. When the transfer layer is release-treated, it is preferable that the release-treated surface constitutes the surface on the resin layer side. However, the transfer layer does not need to be release-treated as long as it can be peeled from the resin layer. The thickness of the transfer layer is not particularly limited, but is, for example, 10 μm or more and 1000 μm or less, preferably 20 μm or more and 600 μm or less, and more preferably 30 μm or more and 400 μm or less.

[0049] (Other layers) Furthermore, the curable resin sheet 10 may have layers other than the transfer layer 12. For example, as shown in Fig. 2, the curable resin sheet 10 may include a release film 13, and the release film 13 may be attached to the surface of the resin layer 11. When the transfer layer 12 is provided, the release film 13 may be provided on the surface of the resin layer 11 opposite to the side on which the transfer layer 12 is provided. The release film 13 is not particularly limited as long as a known release film is used, but it may be made of a resin film, or may be a resin film whose surface has been release-treated with a release agent such as a silicone-based release agent, a non-silicone-based (organic release agent), or a fluorine-based release agent. When the release film 13 is release-treated, the release-treated surface is preferably positioned in contact with the resin layer 11. The release film 13 is preferably peeled from the resin layer 11 and removed from the curable resin sheet 10 before the curable resin sheet 10 is attached to an adherend. Furthermore, although not shown, the curable resin sheet 10 may include a support layer instead of a release film, and the support layer may be attached to the surface of the resin layer 11. The support layer may be formed of resin, rubber, or the like. Similarly to the release film, the support layer may have a release-treated surface that comes into contact with the resin layer 11. The support layer may be provided on the surface of the resin layer 11 opposite to the side on which the transfer layer 12 is provided.

[0050] [Method for manufacturing curable resin sheet] The following mainly describes a method for producing a curable resin sheet in the case where the resin layer is composed of two layers, a colored layer and a clear layer. This production method preferably includes the following steps A, B, and C. (1) Process A In step A, a coating liquid (hereinafter also referred to as the first coating liquid) containing a curable resin composition for the colored layer is applied to a release film and dried to produce a laminate (hereinafter also referred to as the first laminate) comprising the release film and the colored layer provided on the release film.

[0051] The first coating liquid may be a curable resin composition for the colored layer, but from the viewpoint of improving workability such as coatability, it is preferable that the curable resin composition for the colored layer is diluted with a solvent. Examples of the solvent include ethyl acetate, butyl acetate, methyl ethyl ketone, isopropyl alcohol, methyl methacrylate, and toluene.

[0052] Furthermore, the drying carried out after the first coating liquid is applied to the release film is preferably drying that includes at least the main drying step described below, and more preferably drying that carries out the pre-drying step and the main drying step described below in this order.

[0053] The drying temperature in the pre-drying step is preferably from 50° C. to 70° C., more preferably from 55° C. to 65° C. The drying time in the pre-drying step is preferably from 10 minutes to 60 minutes, more preferably from 15 minutes to 45 minutes.

[0054] The drying temperature in this drying step is preferably 85°C or higher and 130°C or lower, and more preferably 90°C or higher and 120°C or lower. When the drying temperature is equal to or higher than these lower limits, the solvent is easily removed appropriately from the coating liquid, and the solvent is prevented from evaporating and causing bubbles when the resin layer is cured. Furthermore, by setting the drying temperature to the above upper limit or lower, the curable resin composition can be prevented from curing more than necessary during drying. The drying time in this drying step is preferably 10 minutes or more and 60 minutes or less, more preferably 15 minutes or more and 45 minutes or less. By setting the drying time to the above lower limit or more, the solvent can be easily removed appropriately from the coating liquid, and the generation of bubbles due to evaporation of the solvent when curing the resin layer can be prevented. Furthermore, by setting the drying time to the above upper limit or less, the curable resin composition can be prevented from curing more than necessary during drying.

[0055] Furthermore, the dried resin layer may be subjected to initial curing as needed. Initial curing refers to curing the curable resin composition constituting the resin layer to a semi-cured state. Initial curing is preferably performed by heating. When initial curing is performed by heating, it is preferably performed under conditions of a heating temperature of 135°C or higher and 150°C or lower, and a heating time of approximately 5 minutes or higher and 10 minutes or lower.

[0056] (2) Process B In step B, a coating liquid containing a curable resin composition for the clear layer (hereinafter also referred to as the second coating liquid) is applied to a substrate for the transfer layer such as a resin film and dried to produce a laminate (hereinafter also referred to as the second laminate) comprising a transfer layer and a clear layer provided on the transfer layer.

[0057] The first coating liquid may be made of a curable resin composition for the colored layer, but is preferably made by diluting the curable resin composition for the colored layer with a solvent from the viewpoint of improving workability such as coatability. The solvent was explained in the section "Step A," so a detailed explanation thereof will be omitted.

[0058] Furthermore, the drying performed after applying the second coating liquid to the transfer layer substrate is preferably drying that includes at least the main drying step described below, similar to the drying performed after applying the first coating liquid to the release film, and more preferably drying that includes the pre-drying step and the main drying step described below in this order. Note that the pre-drying step and the main drying step were explained in the section "Step A," so detailed explanations of them will be omitted.

[0059] (3) Process C In step C, the first laminate and the second laminate are bonded together so that the colored layer and the clear layer face each other. As a result, a curable resin sheet having a laminate structure of release film / colored layer / clear layer / transfer layer can be produced. By peeling the release film from this curable resin sheet, a curable resin sheet consisting of the transfer layer, the clear layer, and the colored layer can be produced.

[0060] The manufacturing method of the curable resin sheet is not limited to the above-mentioned method, and may be appropriately changed according to the structure of the curable resin sheet to be manufactured. For example, when manufacturing a curable resin sheet having a resin layer other than a clear layer and a colored layer, it is advisable to manufacture the curable resin sheet in the same procedure as above, except that the curable resin composition applied to the transfer layer substrate is changed. In addition, when manufacturing a curable resin sheet consisting of a single resin layer, steps B and C can be omitted to obtain a laminate in which a resin layer is provided on a release film.

[0061] Furthermore, when three or more resin layers are provided, a third laminate is first prepared by forming another resin layer on a separately provided release film or the like. Then, the third laminate is bonded to the first laminate to form another resin layer on the resin layer of the first laminate, or the third laminate is bonded to the second laminate to form another resin layer on the resin layer of the second laminate. Thereafter, the first laminate and the second laminate are bonded together as in step C described above to produce a coated sheet having three resin layers. It is recommended that the release film be peeled off after or before laminating the other resin layer on the second or first resin layer. Cured resin sheets having four or more resin layers can also be produced by repeating the same procedure.

[0062] (How to use the curable resin sheet) The curable resin sheet of the present invention is preferably used to form a coating on various articles as adherends. Specifically, the curable resin sheet is attached to various adherends, and then the resin layer is cured, and the cured resin layer is used as a coating. The transfer layer is preferably peeled from the resin layer attached to the adherend and removed from the adherend.

[0063] The substrate to be coated with the curable resin sheet is not particularly limited, but includes electrical appliances, vehicle parts such as vehicle interior materials and vehicle exterior materials, more specifically, vehicle interior materials such as automobile interior materials and interior materials for transportation equipment other than automobiles, vehicle exterior materials such as automobile exterior materials and exterior materials for transportation equipment other than automobiles, miscellaneous goods, heavy machinery, ships, aircraft exterior materials, exterior walls or roofing materials for houses and buildings, bridges, steel frames, plants, wind power generation blades, etc. Among these, vehicle exterior materials such as automobile exterior materials are preferred. Examples of vehicle exterior materials include hoods, roofs, door panels, bumpers, fuel filler panels, trunk lids, rear gates, etc. When the curable resin sheet is attached to a vehicle exterior material, it may be attached to the exterior material attached to the vehicle body, or it may be attached to the exterior material before it is attached to the vehicle body. The material of the adherend is not particularly limited, and may be any of a resin material, an inorganic material such as ceramic, or a metal material such as steel, with metal materials being preferred among these. Metal materials such as steel are difficult to paint simultaneously with molding of the adherend by insert molding, and painting with a resin sheet is difficult, but by using the curable resin sheet of the present invention, such materials can be easily painted.

[0064] The method for attaching the curable resin sheet to the adherend is not particularly limited, and may be performed by hand using a squeegee or the like, or may be performed using a laminating device. Also, the sheet may be attached by press molding, insert injection, vacuum molding, or the like, but among these, vacuum molding is preferred. When attaching by vacuum molding, the curable resin sheet may be heated to, for example, 90°C or higher and 130°C or lower, preferably 100°C or higher and 125°C or lower, and then vacuum molded.

[0065] The curable resin sheet may be pre-shaped to a shape corresponding to the shape of the adherend by vacuum forming, press molding, compressed air molding, etc., and then attached to the adherend. When pre-shaping is performed, the curable resin sheet is preferably pre-shaped in a state where a support layer is attached to the resin layer. Pre-shaping is performed by using a jig to shape the curable resin sheet into a certain shape, but by pre-shaping the curable resin sheet in a state where it has a support layer, it is possible to prevent the resin layer from sticking to the jig. Among the above methods, pre-shaping is preferably performed by vacuum molding. The pre-shaped curable resin sheet may be attached to the adherend after the support layer is removed. In this case, the curable resin sheet may be attached by hand, may be attached to the adherend using a laminating device, or may be attached by other methods.

[0066] The resin layer of the curable resin sheet attached to the adherend as described above may be cured. When the curable resin composition is heat-curable, the resin layer may be cured by heating. When curing by heating, the heating temperature is not particularly limited as long as the resin layer can be cured, but is, for example, 135°C or higher and 170°C or lower, preferably 140°C or higher and 160°C or lower. The heating time is, for example, 30 minutes or higher and 90 minutes or lower, preferably 60 minutes or higher and 90 minutes or lower.

[0067] The present invention also provides a method for manufacturing a vehicle or a vehicle part. The method for manufacturing a vehicle or a vehicle part of the present invention includes a step of painting using the thermosetting resin sheet of the present invention. In the painting step, the vehicle or vehicle part may be painted by the method described in the above-mentioned method of use. [Example]

[0068] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0069] The methods for measuring and evaluating various physical properties are as follows.

[0070] [Adhesive strength] The release film was peeled off from the curable resin sheet obtained in each Example and Comparative Example, and the curable resin sheet was attached to a coated steel plate using a squeegee and water containing 0.5% by mass of a surfactant so that the colored layer and the urethane coating surface were in contact. The curable resin sheet was then peeled off at a peeling speed of 300 mm / min using a variable angle peel tester at a peel angle of 90° under an environment of 23°C and 50% RH, and the adhesive strength per 25 mm was evaluated. Note that this evaluation was not performed in Examples 9, 12, and Comparative Example 3. The evaluation criteria for adhesive strength are as follows: ⊚: A force of 5N or more was required to peel off the curable resin sheet. ◯: A force of 2N or more but less than 5N was required to peel off the curable resin sheet. △: A force of 0.5 N or more but less than 1 N was required to peel off the curable resin sheet. ×: The curable resin sheet was peeled off with a force of less than 0.5 N.

[0071] [Peeling force] The release film was peeled off from the curable resin sheet obtained in each Example and Comparative Example, and the surface that had been in contact with the release film was fixed to a substrate. The transfer layer was peeled at a peel angle of 90° at a peel rate of 300 mm / min using a variable angle peel tester under an environment of 23°C and 50% RH, and the peel force per 25 mm when peeled off was evaluated. Note that this evaluation was not performed in Examples 1 to 8, 11 and Comparative Examples 1 and 2. The evaluation criteria for peel strength are as follows: ⊚: A force of 0.3 N or more was required to peel off the transfer layer. ◯: A force of 0.2 N or more and less than 0.3 N was required to peel off the transfer layer. Δ: A force of 0.1 N or more but less than 0.2 N was required to peel off the transfer layer. ×: The transfer layer was peeled off with a force of less than 0.1 N.

[0072] [Rate of change in adhesive strength or peel strength] The curable resin sheets obtained in each Example and Comparative Example were subjected to an accelerated aging test at 40°C for one week. Before and after the accelerated aging test, the adhesive strength or peel strength of the curable resin sheets was measured using the same method as used for evaluating adhesive strength or peel strength. In Examples 10, 13, and 14 and Comparative Example 4, both the adhesive strength and peel strength were measured before and after the accelerated aging test, while in Examples 1 to 9, 11, and 12 and Comparative Examples 1 to 3, either the adhesive strength or the peel strength was measured before and after the accelerated aging test. The rate of change in adhesive strength or peel strength of the curable resin sheet was evaluated based on the difference between the adhesive strength and peel strength before the accelerated deterioration test and the adhesive strength and peel strength after the accelerated deterioration test. For the curable resin sheets whose adhesive strength was measured, the rate of change in adhesive strength and peel strength was evaluated based on the difference in adhesive strength before and after the accelerated deterioration test, and for the curable resin sheets whose peel strength was measured, the rate of change in adhesive strength and peel strength was evaluated based on the difference in peel strength before and after the accelerated deterioration test.

[0073] The evaluation criteria for the rate of change in adhesive strength and peel strength in Examples 10, 13, and 14 and Comparative Example 4 are as follows. ⊚: Both adhesive strength and peel strength changed by less than 10%. Good: At least one of the adhesive strength and the peel strength changed by 10% or more and less than 25%, and both the adhesive strength and the peel strength changed by less than 25%. Δ: At least one of the adhesive strength and peel strength changed by 25% or more and less than 50%, and both the adhesive strength and peel strength changed by less than 50%. ×: At least one of the adhesive strength and peel strength changed by 50% or more.

[0074] The evaluation criteria for the rate of change in adhesive strength or peel strength in Examples 1 to 9, 11, and 12 and Comparative Examples 1 to 3 are as follows. ⊚: The adhesive strength or peel strength changed by less than 10%. ◯: The adhesive strength or peel strength changed by 10% or more but less than 25%. △: The adhesive strength or peel strength changed by 25% or more but less than 50%. ×: The adhesive strength or peel strength changed by 50% or more.

[0075] The components used in the examples and comparative examples are as follows. <(Meth)acrylic resin> Acrylic polyol resin (A1): solid content 29.6% by mass, Tg = 40°C, hydroxyl value 80 mg KOH / g, weight average molecular weight 250,000, solvent is ethyl acetate Acrylic polyol resin (A2): solid content 29.6% by mass, Tg = 40°C, hydroxyl value 170 mgKOH / g, weight average molecular weight 250,000, solvent is ethyl acetate

[0076] <Synthetic resin> The synthetic resins (a1) to (a10) shown in Table 1 were used.

[0077] [Table 1] *The molecular weights in Table 1 are number average molecular weights. *The unit of OH value is mgKOH / g. The amino value is the number of mmol of amine contained in 1g of solid content of synthetic resin.

[0078] <Blocked isocyanate curing agent> Blocked isocyanate (B1): Isocyanurate-modified hexamethylene diisocyanate-based blocked isocyanate (HDI-based), blocking agent type: Pyrazole-based, solid content (NV) = 68% by mass, recycled NCO amount = 10.4, solvent: ethyl acetate

[0079] <Pigments> "NSP-UP 841B" manufactured by Nichiko Bix Co., Ltd., effective pigment concentration = 9% by mass, solid content (NV) = 24% by mass

[0080] [Example 1] Acrylic polyol resin (A1), synthetic resin (a1), pigment, luster material, and blocked isocyanate were added in the proportions shown in Table 2, and ethyl acetate was added as a solvent to prepare a coating liquid of a curable resin composition for a colored layer (hereinafter also referred to as Coating Liquid A) so that the solids concentration was 40% by mass. The obtained Coating Liquid A was applied to a release film using an applicator. Thereafter, a pre-drying process was carried out under conditions of a drying temperature of 60°C and a drying time of 20 minutes, and the colored layer was subjected to a main drying process under conditions of a drying temperature of 80°C and a drying time of 5 minutes, forming a colored layer with a thickness of 30 μm on the release film.

[0081] Next, acrylic polyol resin (A1), synthetic resin (a1), and blocked isocyanate were added in the proportions shown in Table 2, and ethyl acetate was added as a solvent to prepare a coating liquid of the curable resin composition for the clear layer (hereinafter also referred to as coating liquid B) so that the solids concentration was 40% by mass. The obtained coating liquid B was applied to the smooth surface of the unstretched cyclic polyolefin film (manufactured by Toray Industries, Inc., "Decofit Q16CK") constituting the transfer layer using an applicator. Thereafter, a pre-drying process was carried out under conditions of a drying temperature of 60 ° C. and a drying time of 20 minutes, and the clear layer was subjected to a main drying process under conditions of a drying temperature of 80 ° C. and a drying time of 5 minutes, forming a clear layer with a thickness of 80 μm on the transfer layer, and a clear layer with a thickness of 30 μm on the transfer layer.

[0082] The colored layer on the release film and the clear layer on the transfer layer were attached together and laminated at room temperature to obtain a curable resin sheet in which the release film, colored layer, clear layer, and transfer layer were laminated in this order, and various evaluations were performed. The results are shown in Table 2.

[0083] [Examples 2 to 10, 13, and 14, and Comparative Examples 1 to 4] Except for changing the formulation of the curable resin composition used to prepare each coating liquid as shown in Tables 2 to 4, curable resin sheets having a release film, a colored layer, a clear layer, and a transfer layer laminated in this order were obtained in the same manner as in Example 1, and various evaluations were carried out. The results are shown in Tables 2 to 4.

[0084] [Example 11] Except for changing the formulation of the curable resin composition used to prepare Coating Solution A as shown in Table 3 and forming only a colored layer without forming a clear layer, a curable resin sheet consisting of a transfer layer and a colored layer formed on the transfer layer was obtained in the same manner as in Example 1, and various evaluations were carried out. The results are shown in Table 3.

[0085] [Example 12] Except for changing the formulation of the curable resin composition used to prepare Coating Solution A as shown in Table 3 and forming only a clear layer without forming a colored layer, a curable resin sheet consisting of a transfer layer and a clear layer formed on the transfer layer was obtained in the same manner as in Example 1, and various evaluations were performed. The results are shown in Table 3.

[0086] [Table 2]

[0087] [Table 3]

[0088] [Table 4]

[0089] As is clear from the above examples, curable resin sheets that satisfy the requirements of the present invention have good adhesive strength and / or peel strength, and no significant change was observed in the rate of change in adhesive strength or peel strength. In contrast, the curable resin sheets produced in Comparative Examples 1, 3, and 4 could not achieve good adhesive strength or peel strength because the molecular weight of the synthetic resin contained in the curable resin composition for the resin layer was too high. Also, the curable resin sheet produced in Comparative Example 2 suffered from a large change in the rate of change in adhesive strength or peel strength because the molecular weight of the synthetic resin contained in the curable resin composition for the resin layer was too low. [Explanation of symbols]

[0090] 10. Hardening resin sheet 11 Resin layer 12 Transfer layer 13 Release film

Claims

1. at least one resin layer made of a curable resin composition containing a (meth)acrylic resin and a blocked isocyanate; at least one of the resin layers is made of a curable resin composition having a functional group reactive with isocyanate and further containing a synthetic resin other than a (meth)acrylic resin; The molecular weight of the synthetic resin is 1,000 or more and 5,000 or less.

2. The curable resin sheet according to claim 1 , comprising two or more resin layers.

3. The curable resin sheet according to claim 2 , wherein the resin layer comprises a colored layer and a clear layer.

4. The curable resin sheet according to claim 1 or 2, further comprising a transfer layer.

5. The curable resin sheet according to claim 1 or 2, wherein the synthetic resin has at least one functional group selected from the group consisting of a hydroxyl group, an amino group, an isocyanate group, and a carboxyl group.

6. The curable resin sheet according to claim 1 or 2, wherein the synthetic resin has a glass transition temperature of 60°C or lower.

7. The curable resin sheet according to claim 1 or 2, wherein the content of the synthetic resin is 40 mass% or less based on the total amount of the (meth)acrylic resin and the synthetic resin.

8. The curable resin sheet according to claim 1 or 2, wherein the (meth)acrylic resin contains a (meth)acrylic resin having a plurality of functional groups and a weight average molecular weight of 50,000 or more and 1,000,000 or less.

9. A vehicle painted with the curable resin sheet according to claim 1 or 2.

10. A vehicle part coated with the curable resin sheet according to claim 1 or 2.

11. A method for manufacturing a vehicle, comprising a step of painting using the thermosetting resin sheet according to claim 1 or 2.

12. A method for manufacturing a vehicle part, comprising a step of painting using the thermosetting resin sheet according to claim 1 or 2.

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