Transfer-type curable resin sheet for coating and method for forming coating

Abstract

To provide a transfer type curable resin sheet for coating which can be suitably adhered to various articles by vacuum molding or the like without causing breakage or the like and is excellent in scratch resistance.SOLUTION: The transfer type curable resin sheet for coating comprises a coating layer comprising a curable resin composition curable by heat, moisture or active energy rays and a transfer layer comprising a thermoplastic resin, wherein the tack value of the coating layer at 23 °C on the surface opposite to the surface on which the transfer layer is provided is 300-4,000 N / cm2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a transfer-type curable resin sheet for coating, and a method for forming a coating using the transfer-type curable resin sheet for coating. [Background technology]

[0002] Traditionally, painting has been applied to various products such as furniture, steel plates, and vehicle bodies to impart functionality such as design, durability, weather resistance, and scratch resistance. When industrially painting three-dimensional products, the paint is typically sprayed using air or electrostatic force. However, due to the waste generated during painting, CO2 emissions from factories, and the large-scale capital investment required for spray painting, replacement with decorative technology using resin films has recently been considered.

[0003] Decorative technology is a technique used in various fields, such as household electrical appliances, automotive interior parts, and miscellaneous goods, to decorate the surface of a product by attaching a resin film (decorative film) printed with letters or patterns in white, black, or color ink. For example, Patent Document 1 proposes a painted film as a decorative film, which has a protective layer formed on a film substrate from an active energy ray-curable composition. Patent Document 1 describes that forming the protective layer from an active energy ray-curable composition with a specific composition can improve the chemical resistance, scratch resistance, and other properties of the painted surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5394995 Summary of the Invention [Problem to be solved by the invention]

[0005] In the coated film disclosed in Patent Document 1, the base film itself is not adhesive, so in order to attach it to various products, an adhesive layer made of an adhesive is generally formed on the surface opposite the protective layer. However, when attached using an adhesive, peeling easily occurs over time, making it unsuitable for outdoor applications that require durability and weather resistance.

[0006] Furthermore, by using a paint film such as that disclosed in Patent Document 1, it is possible to form a surface layer equivalent to a paint on the surface of a plastic molded product by insert molding so that the paint film decorates the surface while molding the plastic raw material supplied from an injection mold. However, because this method presupposes injection molding, it is difficult to apply it to materials other than plastic materials, such as steel plate materials.

[0007] For application to steel plate materials, etc., vacuum forming can be considered for application, but with vacuum forming, the film itself must have adhesive properties in order to be properly attached to the surface of various products. On the other hand, if adhesive properties are given to the film itself, the film becomes flexible and vulnerable to scratches.

[0008] Therefore, an object of the present invention is to provide a transfer-type curable resin sheet for painting that can be appropriately attached to various articles by vacuum forming or the like and has excellent scratch resistance. [Means for solving the problem]

[0009] As a result of extensive investigation, the present inventors have found that the above-mentioned problems can be solved by providing a resin sheet with a transfer-type multilayer structure having a paint layer containing a curable resin composition and a transfer layer, and by setting the tack value at 23°C of the adhesive surface of the paint layer within a certain range, and have completed the present invention as described below. That is, the present invention provides the following [1] to [8]. [1] A transfer-type curable resin sheet for painting, comprising a paint layer containing a curable resin composition that can be cured by heat, moisture, or active energy rays, and a transfer layer containing a thermoplastic resin, wherein the tack value at 23°C of the surface of the paint layer opposite to the surface on which the transfer layer is provided is 300 N / cm 2 More than 4000N / cm 2 The following is a transfer-type curable resin sheet for painting. [2] The transfer-type curable resin sheet for coating according to [1], wherein the transfer layer has a tensile elongation at break of 500% or more in both MD and TD at 120°C. [3] The transfer-type curable resin sheet for coating according to [1] or [2], wherein the transfer layer has a tensile elongation at break in both MD and TD at 100°C of 500% or more. [4] The transfer-type curable resin sheet for coating according to any one of [1] to [3], wherein the curable resin composition contains a (meth)acrylic resin (A) having a weight-average molecular weight of 100,000 or more and 1,000,000 or less, being solid and having multiple functional groups. [5] The transfer-type curable resin sheet for painting according to [4], wherein the (meth)acrylic resin (A) is a (meth)acrylic polyol (A1), and the curable resin composition contains a blocked isocyanate (B). [6] The transfer-type curable resin sheet for coating according to [4], wherein the (meth)acrylic resin (A) is a polymer (A2) having a (meth)acryloyl group, and contains a radical polymerization initiator (C) that generates radicals when exposed to heat or active energy rays. [7] A method for forming a coating, comprising attaching the transfer-type curable resin sheet for coating according to any one of [1] to [6] to an object to be coated, and then curing the paint layer to form a coating. [8] The method for forming a coating according to [7], wherein the transfer layer is peeled off from the paint layer and removed from the object to be coated. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a transfer-type curable resin sheet for coating that can be appropriately adhered to various articles by vacuum forming or the like and has excellent scratch resistance. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view showing an example of a transfer-type curable resin sheet for painting. [Figure 2] 1 is a schematic cross-sectional view showing an example of a transfer-type curable resin sheet for painting. [Figure 3] 1 is a schematic cross-sectional view showing an example of a transfer-type curable resin sheet for painting. [Figure 4] 1 is a schematic cross-sectional view showing an example of a method for forming a coating on an object to be coated. [Figure 5] FIG. 1 is a schematic diagram of an apparatus for performing TOM molding. [Figure 6] 1 is a schematic cross-sectional view showing an example of a method for forming a coating on an object to be coated. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in more detail below using embodiments. The transfer-type curable resin sheet for coating of the present invention (hereinafter sometimes simply referred to as "transfer-type resin sheet") is a multilayer sheet comprising a paint layer and a transfer layer. In the transfer-type resin sheet, the paint layer is formed on one side of the transfer layer, and the two are integrated. The paint layer contains a curable resin composition that can be cured by heat, moisture, or active energy rays. The transfer layer contains a thermoplastic resin. The transfer resin sheet is attached to various articles (hereinafter also referred to as the object to be coated) to be coated with a paint layer so that the paint layer contacts the object to be coated. The paint layer is then cured to form a cured paint layer on the surface of the object to be coated, and the cured paint layer forms a coating. For example, after the paint layer has cured, the transfer layer may be peeled off from the paint layer and removed from the object to be coated.

[0013] The paint layer and transfer layer used in the transfer resin sheet will be described in detail below.

[0014] <Paint layer> The paint layer constituting the transfer resin sheet of the present invention has a tack value at 23°C (hereinafter simply referred to as "tack value") of 300 N / cm on the surface opposite to the surface on which the transfer layer described below is provided. 2 More than 4000N / cm 2 If the tack value is below the lower limit, the coating will not adhere well to the substrate, whereas if the tack value is above the upper limit, the hardness of the cured coating will not be sufficiently improved, and excellent scratch resistance will not be achieved. From the above viewpoint, the tack value is 500N / cm 2 More than 3000N / cm 2 Preferably less than 700N / cm 2 More than 2500N / cm 2 The following is more preferred: The paint layer is used, for example, to protect or beautify the adherend, or to impart other unique functions. The paint layer may be a colored layer or a clear layer, as described below. Furthermore, the unique function of the paint layer can be, for example, a function as a heat-shielding coating. In this case, it is preferable that the coating formed by the paint layer functions as a heat-shielding coating. In this case, it is preferable to include a heat-shielding material in the thermosetting resin composition, and to make the paint layer a heat-shielding layer. Furthermore, by providing the paint layer with surface irregularities, it is possible to impart surface properties such as matte or grained finishes. Other functions such as rust prevention, mildew prevention, heat insulation, and antistatic properties can also be achieved by incorporating components appropriate for the purpose into the curable resin composition. The surface of the paint layer opposite to the surface on which the transfer layer is provided becomes the attachment surface that is attached to the object to be coated.

[0015] The coating layer used in the present invention is made of a curable resin composition that can be cured by heat, moisture, or active energy rays. Examples of active energy rays include ultraviolet rays, electron beams, ionizing radiation such as α-rays, β-rays, and γ-rays, but any energy species can be used as long as it can generate radical active species. Among these, the curable resin composition is preferably a curable resin composition that can be cured by heat or active energy rays. The curable resin composition preferably contains a resin containing a functional group that can be cured by reacting with itself or with a curing agent due to heat, moisture, or active energy rays. Resins used in the curable resin composition include curable resins. Specifically, resins that are cured by heat or active energy rays include (meth)acrylic resins, polycarbonate resins, polyester resins, and epoxy resins, with (meth)acrylic resins being preferred. Furthermore, as resins that are cured by moisture, moisture-curable resins, as described below, are preferably used. Hereinafter, a detailed description will be given of the case where at least a (meth)acrylic resin is used as the resin in the curable resin composition.

[0016] ((Meth)acrylic resin) Examples of (meth)acrylic resins include (meth)acrylic resins having multiple functional groups. The functional group is a group capable of reacting with heat or active energy rays. Preferred examples of the functional group include functional groups that react with functional groups (e.g., isocyanate groups) contained in the curing agent described below, and functional groups having photopolymerizable unsaturated bonds. Specific examples include hydroxyl groups, amino groups, carboxyl groups, (meth)acryloyl groups, vinyl groups, and glycidyl groups. The (meth)acrylic resin may have only one type of functional group, or two or more types. Of these, it is preferable that the (meth)acrylic resin has at least one of a hydroxyl group and a (meth)acryloyl group. Therefore, the (meth)acrylic resin is preferably a (meth)acrylic polyol having a plurality of hydroxyl groups or a polymer having a plurality of (meth)acryloyl groups.

[0017] 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.

[0018] 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 approximately 1 to 18 carbon atoms, such as methyl (meth)acrylate and ethyl (meth)acrylate, (meth)acrylates having an aromatic ring, such as benzyl (meth)acrylate and phenoxydiethylene glycol (meth)acrylate, and 2-ethoxyethyl (meth)acrylate.

[0019] Examples of functional group-containing monomers include hydroxyl group-containing monomers, amino group-containing monomers, and carboxyl group-containing monomers. These may be used alone or in combination of two or more. Of the above-mentioned functional group-containing monomers, hydroxyl group-containing monomers are preferred. The above-mentioned (meth)acrylic polyol can be obtained by polymerizing a monomer mixture containing a (meth)acrylic acid ester monomer and a hydroxyl group-containing monomer.

[0020] The hydroxyl group-containing monomer is not particularly limited, and examples thereof include (meth)acrylic acid ester monomers having a hydroxyl group, such as 2-hydroxyethyl (meth)acrylate. The amino group-containing monomer is not particularly limited, and examples thereof include (meth)acrylic acid ester monomers having an amino group, such as 2-aminoethyl (meth)acrylate. The carboxyl group-containing monomer is not particularly limited, and examples thereof include (meth)acrylic acid. The styrene derivative monomer is not particularly limited, and examples thereof include styrene, α-methylstyrene, α-ethylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-ethoxystyrene, p-chlorostyrene, m-chlorostyrene, and o-chlorostyrene.

[0021] The (meth)acrylic resin may also be a copolymer obtained by block or graft polymerization of the above-mentioned acrylic polymer with another monomer or polymer, such as an acrylic, styrene, maleic acid, imide, silicone, or fluorine-based monomer, or a polymer of such a monomer. Furthermore, the functional group of an acrylic polymer obtained by polymerizing a monomer mixture containing a (meth)acrylic acid ester monomer and a functional group-containing monomer may be reacted with a (meth)acryloyl group-containing compound having a reactive group capable of reacting with the functional group and a (meth)acryloyl group, thereby allowing the acrylic polymer to contain a (meth)acryloyl group.

[0022] As the polymer having a (meth)acryloyl group, like the acrylic polymer described above, the main chain preferably has an acrylic skeleton having a structural unit derived from a (meth)acrylic acid ester; however, the main chain does not necessarily have to have an acrylic skeleton, and as long as it has a (meth)acryloyl group, the main chain does not necessarily have to have an acrylic skeleton, and may have, for example, a urethane skeleton.

[0023] The curable resin composition preferably contains, as the (meth)acrylic resin, a (meth)acrylic resin (hereinafter referred to as (meth)acrylic resin (A)) that has a weight-average molecular weight (Mw) of 100,000 or more and 1,000,000 or less, is solid, and 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 paint layer in a consistent shape even before curing, and facilitates the appropriate formation of the paint layer on the transfer layer. It also makes it easier to impart tackiness and extensibility to the paint layer. The tackiness and extensibility of the paint layer make it easier to adhere to the substrate without tearing during vacuum molding or the like, improving vacuum moldability. Furthermore, a weight-average molecular weight within the above range makes it easier to increase the hardness of the paint layer after curing. From the above viewpoints, the weight average molecular weight of the (meth)acrylic resin (A) is preferably 150,000 or more and 500,000 or less, and more preferably 180,000 or more and 450,000 or less. In this specification, the weight average molecular weight is measured by gel permeation chromatography (GPC) and is calculated as a standard polystyrene equivalent value. Furthermore, "solid" refers to a substance that is solid at room temperature (23°C) and atmospheric pressure (1 atm). Similarly, "liquid" refers to a substance that is liquid at room temperature (23°C) and atmospheric pressure (1 atm).

[0024] 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 coating layer. In this specification, the glass transition temperature is a value determined by differential scanning calorimetry (DSC) in accordance with JIS K 7121.

[0025] The high molecular weight (meth)acrylic resin (A) is preferably at least one of a (meth)acrylic polyol having a plurality of hydroxyl groups (hereinafter also referred to as a (meth)acrylic polyol (A1)) and a polymer having a (meth)acryloyl group (hereinafter also referred to as a polymer (A2)). As described above, the (meth)acrylic polyol (A1) 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 (A1) 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 is easy to achieve high hardness of the coating layer after curing. The hydroxyl value can be measured in accordance with JIS K1557-1:2007.

[0026] The polymer (A2) preferably contains a predetermined proportion of (meth)acryloyl groups, specifically, the (meth)acryloyl group equivalent is preferably 100 g / mol to 10,000 g / mol, more preferably 500 g / mol to 8,000 g / mol. By setting the (meth)acryloyl group equivalent within the above range, the curability of the coating layer containing the polymer (A2) is improved, and the coating layer is likely to have high hardness after curing. The (meth)acryloyl group equivalent means the value obtained by dividing the weight average molecular weight of the polymer by the number of (meth)acryloyl groups in one molecule of the polymer.

[0027] The content of the (meth)acrylic resin (A) in the coating layer is not particularly limited, but is, for example, 18% by mass or more, preferably 19% by mass or more, and more preferably 20% by mass or more, based on the total amount of the curable resin composition. By containing a certain amount or more of the (meth)acrylic resin (A), the coatability and curability of the curable resin composition can be easily improved. The content of the (meth)acrylic resin (A) in the coating layer is not particularly limited, but is, for example, 60 mass % or less, preferably 55 mass % or less, and more preferably 50 mass % or less, based on the total amount of the curable resin composition. By reducing the content of the (meth)acrylic resin (A), it becomes easier to improve the tackiness of the curable resin composition. In this specification, the term "based on the total amount of the curable resin composition" means that, when the curable resin composition contains a solvent, the total of the components excluding the solvent is 100 mass %. In other words, the term "based on the total amount of the curable resin composition" means the total amount of the solid content of the curable resin composition. The (meth)acrylic resin (A) may be used alone or in combination of two or more kinds.

[0028] The curable resin composition preferably contains, as the resin, a plasticizing resin (a) having a weight-average molecular weight of less than 100,000 in addition to the (meth)acrylic resin (A). The plasticizing resin (a) is preferably one that can plasticize the curable resin composition before curing and adjust the tack value of the paint layer to a desired range. The plasticizing resin (a) is preferably one that is compatible with the (meth)acrylic resin (A) and, like the (meth)acrylic resin (A), has a functional group that can be cured by heat or active energy rays. Examples of resins that can be used for the plasticizing resin (a) include (meth)acrylic resins, polycarbonate resins, polyester resins, epoxy resins, polyether resins, polyolefin resins, and plant-derived resins (such as castor oil), with (meth)acrylic resins and polycarbonate resins being preferred. The curable resin composition contains a plasticizing resin (a) in addition to a high molecular weight (meth)acrylic resin (A), which makes it easier to achieve a good balance between the tackiness, coatability, curability of the coating layer, and extensibility of the curable resin composition. The weight average molecular weight of the plasticizing resin (a) is preferably 100 or more and 30,000 or less, and more preferably 300 or more and 20,000 or less.

[0029] Furthermore, the plasticized resin (a) is desirably a liquid when its solid content is 100%. The plasticized resin (a) may or may not have a glass transition temperature. When the plasticized resin (a) has a glass transition temperature, the glass transition temperature is not particularly limited, but is preferably less than 0°C, more preferably -20°C or lower, and even more preferably -40°C or lower. The lower limit of the glass transition temperature is not particularly limited, but is, for example, -120°C or higher, preferably -100°C or higher. When the glass transition temperature of the plasticized resin (a) is within the above range, it becomes easier to adjust the tensile elongation at break of the paint layer to a desired range, and it also becomes easier to develop tackiness.

[0030] The plasticizing resin (a) is preferably at least one of a (meth)acrylic polyol or polycarbonate diol having multiple hydroxyl groups (hereinafter also referred to as polyol (a1)), and a polymer having a (meth)acryloyl group (hereinafter also referred to as polymer (a2)). The hydroxyl value of the (meth)acrylic polyol or polycarbonate diol (polyol (a1)) is preferably 20 mgKOH / g or more and 300 mgKOH / g or less, more preferably 50 mgKOH / g or more and 250 mgKOH / g or less. By setting the hydroxyl value within the above range, the curability is improved, and it is easy to achieve high hardness of the coating layer after curing. The (meth)acryloyl group-containing polymer (a2) preferably has a (meth)acryloyl group equivalent of 10 g / mol to 10,000 g / mol, more preferably 100 g / mol to 8,000 g / mol. By setting the (meth)acryloyl group equivalent within the above range, the curability is improved, and it is easy to achieve high hardness of the coating layer after curing.

[0031] The (meth)acrylic polyol or polycarbonate diol (polyol (a1)) is preferably used when the high-molecular-weight (meth)acrylic resin (A) is a (meth)acrylic polyol (A1). By using the (meth)acrylic polyol or polycarbonate diol (polyol (a1)) in combination with the (meth)acrylic polyol (A1), the curable resin composition can be easily cured appropriately by heating. The polymer (a2) is preferably used when the high-molecular-weight (meth)acrylic resin (A) is a polymer (A2) having a (meth)acryloyl group. By using the polymer (a2) and the polymer (A2) in combination, the curable resin composition can be easily cured appropriately by irradiation with active energy rays, heating, or the like. The plasticizing resin (a) may be used alone or in combination of two or more kinds.

[0032] In the paint layer, the ratio of the total content of the plasticizing resin (a) and the blocked isocyanate (B) to the (meth)acrylic resin (A) (hereinafter also referred to as "(a+B) / A") is, for example, 0.8 or more, preferably 0.9 or more, and more preferably 1.0 or more. When (a+B) / A is a certain level or more, that is, when the paint layer contains a certain level or more of the plasticizing resin (a) and the blocked isocyanate (B), the tack value of the curable resin composition can be made to be a certain level or more, and adhesion and other properties can be easily improved. Furthermore, (a+B) / A is, for example, not more than 5, preferably not more than 4.5, and more preferably not more than 4. By setting (a+B) / A to a certain level or less, the hardness of the cured product of the curable resin composition can be made to be not less than a certain level, and excellent scratch resistance can be imparted. When the curable resin composition contains a solvent, (a+B) / A is the blending ratio based on the total amount of solids as described above. The same applies to a / A, which will be described later.

[0033] (Blocked isocyanate (B)) The curable resin composition of the present invention may contain a curing agent that reacts with the curable resin to cure it. The curing agent is preferably a heat-curing agent that reacts with the curable resin by heating. When a (meth)acrylic polyol (A1) is used as the heat-curing agent, a blocked isocyanate (B) is preferably used. That is, in one embodiment, the curable resin composition of the present invention preferably contains a (meth)acrylic polyol (A1) and a blocked isocyanate (B).

[0034] The blocked isocyanate (B) is a compound in which an isocyanate group is blocked with a protecting group. When exposed to high temperatures, the protecting group (blocking moiety) is thermally dissociated and removed, and a curing reaction occurs between the resulting isocyanate group and the above-mentioned (meth)acrylic polyol (A1), (meth)acrylic polyol, or polycarbonate diol (polyol (a1)). The blocked isocyanate (B) can be obtained, for example, by reacting an isocyanate compound having two or more isocyanate groups in one molecule with a blocking agent. The isocyanate compound having two or more isocyanate groups in one molecule is not particularly limited, but examples thereof include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, and modified products thereof. Examples of blocking agents include pyrazoles, phenols, oximes, lactams, and active methylenes.

[0035] The amount of the blocked isocyanate (B) blended in the curable resin composition is preferably such that the ratio of the number of functional groups in the (meth)acrylic polyol (A1) to the number of isocyanate groups in the blocked isocyanate (B) (number of functional groups / number of isocyanate groups) is 0.4 or more and 2.5 or less, and more preferably 0.6 or more and 1.4 or less. The content of the blocked isocyanate (B) is not particularly limited, but is preferably 20% by mass or more and 50% by mass or less, and more preferably 25% by mass or more and 45% by mass or less, based on the total amount of the curable resin composition.

[0036] (Radical polymerization initiator (C)) The curable resin composition of the present invention may contain a radical polymerization initiator (C) that generates radicals when exposed to heat or active energy rays. When a polymer (A2) having a (meth)acryloyl group is used in the curable resin composition, it is preferable to use the radical polymerization initiator (C). That is, in one embodiment, the curable resin composition of the present invention preferably contains a polymer (A2) having a (meth)acryloyl group and the radical polymerization initiator (C).

[0037] Examples of thermal radical polymerization initiators that generate radicals by heat include azo compounds, organic peroxides, etc. Examples of azo compounds include 2,2'-azobis(2,4-dimethylvaleronitrile) and azobisisobutyronitrile. Examples of organic peroxides include benzoyl peroxide, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, peroxyester, diacyl peroxide, and peroxydicarbonate. Examples of photoradical polymerization initiators that generate radicals when exposed to active energy rays include benzophenone-based compounds, alkylphenone-based compounds, acetophenone-based compounds, acylphosphine oxide-based compounds, titanocene-based compounds, oxime ester-based compounds, benzoin ether-based compounds, and thioxanthone. The radical polymerization initiator (C) is preferably a photoradical polymerization initiator.

[0038] The content of the radical polymerization initiator (C) in the curable resin composition is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 7% by mass or less, and even more preferably 0.2% by mass or more and 5% by mass or less, based on the total amount of the curable resin composition. When the content of the radical polymerization initiator (C) is within these ranges, the curable resin composition can be cured with high curability by heating or irradiation with active energy rays.

[0039] When the curable resin composition is to be a moisture-curable curable resin composition, it is preferable to include a moisture-curable resin in the composition. Examples of the moisture-curable resin include a prepolymer having an isocyanate group at its terminal. Examples of the prepolymer having an isocyanate group at its terminal include those obtained by reacting a polyisocyanate with an active hydrogen-containing compound and / or an active hydrogen-containing polymer. Examples of polyisocyanates that can be used in preparing a prepolymer having an isocyanate group at its terminal include tolylene diisocyanate, crude tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, carbazimidated diphenylmethane diisocyanate, phenylene diisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate, and hexamethylene diisocyanate, and preferably polymethylene polyphenyl isocyanate.

[0040] As the active hydrogen-containing compound and active hydrogen-containing polymer, for example, the following can be used. Active hydrogen-containing polymers having two or more terminal hydroxyl groups and an average molecular weight of 3,000 or less, an average number of functional groups of 2 or more, preferably an average molecular weight of 200 to 1,000, and an average number of functional groups of 2 to 2.5, are usable, which are obtained by addition polymerization of active hydrogen-containing compounds such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolethane, trimethylolpropane, castor oil, diglycerin, sorbitol, pentaerythritol, dipentaerythritol, or a mixture of the above-mentioned active hydrogen-containing compounds and alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, or tetrahydrofuran. Other active hydrogen-containing polymers that can be used in combination include polyester polyols, oil-modified polyester polyols, poly-ε-caprolactone polyols, polycarbonate diols, acrylic polyols, polyamines, polyamides, urea resins, and melamine resins, which have an average molecular weight of 3,000 or less and an average number of functional groups of 1.5 or more, preferably an average molecular weight of 200 to 1,000 and an average number of functional groups of 2 to 2.5. The prepolymer having a terminal isocyanate group has, for example, an effective NCO content of 1 to 15 mass %, preferably 8 to 13 mass %.

[0041] A prepolymer having a terminal isocyanate group can be synthesized by carrying out a urethane reaction of the above polyisocyanate and a conventional polyol containing the above active hydrogen-containing polymer under conditions of excess isocyanate at a temperature of 40°C to 90°C, preferably 55°C to 75°C, in a moisture-free system.

[0042] The urethanization reaction is typically carried out in an organic solvent, such as a ketone solvent (e.g., methyl ethyl ketone), an ester solvent (e.g., ethyl acetate), an aromatic solvent (e.g., toluene, xylene), or another solvent commonly used in paints. The urethanization reaction can also be carried out using a catalyst, such as a tertiary amine catalyst (e.g., triethylamine, dimethylaniline), or a metal catalyst (e.g., tin, zinc). These catalysts also act as catalysts when reacting with moisture in the air during coating film formation.

[0043] (Pigment (D)) The curable resin composition may contain a pigment (D). By adding the pigment (D) to the curable resin composition, the paint layer can be colored to form a colored layer, or the paint layer can be given brilliance, etc. Therefore, the design of the paint formed by the transfer resin sheet can be improved. Examples of the pigment (D) include aluminum pigments such as aluminum flakes, luster pigments such as mica pigments, graphite pigments, and glass flake pigments, metal oxide pigments such as titanium oxide, iron oxide, and titanium yellow, 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, but are not limited to these.

[0044] The content of the active ingredient of the pigment (D) in the paint layer, i.e., the pigment component excluding the binder resin, dispersant, and additives, is, for example, 0.1% by mass to 50% by mass, preferably 0.5% by mass to 40% by mass, and more preferably 1% by mass to 30% by mass, based on the total amount of the curable resin composition. By setting the content of the pigment (D) at or above these lower limits, it is possible to appropriately color the paint formed by the transfer resin sheet or to appropriately impart luster to the paint. Furthermore, by setting the content of the pigment (D) at or below the above upper limits, it is possible to prevent the pigment (D) from deteriorating various properties of the paint layer, such as shape retention, curability, extensibility, and tackiness.

[0045] The curable resin composition may contain a colorant other than the pigment (D), or may contain a dye. As the dye, known dyes can be used, such as azo dyes, anthraquinone dyes, indigoid dyes, and stilbene dyes. The curable resin composition may also contain components other than those described above, such as additives other than those described above, such as adhesion promoters, urethane reaction catalysts, urethane reaction modifiers, antifoaming agents, surface modifiers, wax additives, crosslinking agents, dispersants, inorganic fillers other than pigments, antioxidants, antioxidants, ultraviolet absorbers, and rust inhibitors.

[0046] The paint layer may have a single-layer structure or a multi-layer structure. In the case of a single-layer structure, the paint layer may consist of one layer made of the curable resin composition. In the case of a multi-layer structure, each layer may consist of the curable resin composition. In the case of a multi-layer structure, for example, a plurality of layers made of the curable resin composition, each of which has a different composition from the other adjacent layers, may be laminated. In the case of a multi-layer structure, the paint layer may comprise, for example, at least one of a colored layer containing a pigment or a colorant other than a pigment, and a clear layer containing neither a pigment nor a colorant other than a pigment. However, it is preferable for the paint layer to comprise both a colored layer and a clear layer. When a colored layer and a clear layer are provided, the clear layer and the colored layer are preferably arranged in this order from the transfer layer side. With this layer structure, when the transfer resin sheet is attached to an adherend, the colored layer and the clear layer are arranged in this order from the adherend side. As described above, the paint layer has a colored layer, so that the adherend can be colored by the coating formed by the paint layer. Furthermore, by providing a clear layer in addition to the colored layer, the colored layer can be protected and glossy.

[0047] The clear layer is a transparent layer and is only required 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, it is preferable that the transmittance of light at a wavelength of 450 nm is 80% or more. The clear layer is preferably a coating film that does not contain a colorant, but may contain a small amount of colorant as long as it does not impair its function. Furthermore, when a (meth)acrylic resin is used as the curable resin, the curable resin composition for the clear layer only needs to contain at least a high molecular weight (meth)acrylic resin, in which case it may or may not contain a plasticizing resin.

[0048] Of course, when the paint 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 paint layer 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.

[0049] The thickness of the paint layer is not particularly limited, but is, for example, about 5 μm or more and 1000 μm or less, and preferably 10 μm or more and 500 μm or less. When a colored layer and a clear layer are provided on the paint 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.

[0050] The curable resin composition constituting the paint layer may be in an uncured or semi-cured state. The uncured or semi-cured state refers to a state in which curing further progresses when the paint layer is heated or irradiated with active energy rays. The semi-cured state refers to a state in which the curable resin composition is partially cured, and the uncured state refers to a state in which the curable resin composition is not cured.

[0051] <Transfer layer> In the transfer resin sheet of the present invention, the transfer layer serves as a support when transferring the paint layer to an adherend such as a vehicle body. The transfer layer preferably has a tensile elongation at break of 500% or more in both MD and TD at 120°C. If the tensile elongation at break of the transfer layer in both MD and TD is 500% or more, when the transfer resin sheet is attached to the object by vacuum forming or the like, the transfer resin sheet will be able to easily conform to the shape of the object, making it easier to prevent breakage, wrinkles, and the like, and to make it easier to properly adhere the transfer resin sheet to the object. In order to provide excellent vacuum formability and to allow the transfer resin sheet to adhere more appropriately to the substrate, it is preferable that the tensile elongation at break in both MD and TD of the transfer layer at 120°C is 600% or more, and it is even more preferable that both are 700% or more. Further, the upper limit of the tensile elongation at break at 120°C is not particularly limited, but the tensile elongation at break in the MD and TD at 120°C may be, for example, 3000% or less.

[0052] The transfer layer preferably has a tensile elongation at break of 500% or more in both MD and TD at 100° C. If the transfer layer has a tensile elongation at break of 500% or more in both MD and TD, when the transfer resin sheet is attached to an object to be coated by vacuum forming or the like, the transfer resin sheet will be able to easily conform to the shape of the object to be coated, making it easier to prevent breakage, wrinkles, and the like, and also making it easier to properly adhere the transfer resin sheet to the object to be coated. In order to provide excellent vacuum formability and to allow the transfer resin sheet to adhere more appropriately to the substrate, it is preferable that the tensile elongation at break in both MD and TD of the transfer layer at 100°C is 600% or more, and it is even more preferable that both are 700% or more. Further, the upper limit of the tensile elongation at break at 100°C is not particularly limited, but the tensile elongation at break in the MD and TD at 120°C may be, for example, 3000% or less. The transfer layer may have both MD and TD tensile elongations at break within the above range at at least one of 100° C. and 120° C. For example, when the vacuum forming temperature is relatively high, the MD and TD tensile elongations at break may be within the above range at 120° C., and when the vacuum forming temperature is relatively low, the MD and TD tensile elongations at break may be within the above range at 100° C.

[0053] The tensile elongation at break of the transfer layer at 100°C and 120°C is the elongation at break measured in a tensile test of the film constituting the transfer layer, and can be measured by a measurement method in accordance with JIS K7127. The tensile elongation at break of the transfer layer at 100°C and 120°C can be adjusted appropriately depending on the type of resin constituting the transfer layer, whether or not the resin film constituting the transfer layer is stretched, and the degree of stretching.

[0054] The transfer layer is made of a thermoplastic resin. By using a thermoplastic resin as the transfer layer, the tensile elongation at break at at least one of 100°C and 120°C is increased, and when the transfer resin sheet is attached to the substrate, the transfer resin sheet can easily conform to the shape of the substrate. In addition, the occurrence of breaks, wrinkles, etc. is easily prevented, and the transfer resin sheet can easily be properly adhered to the substrate. Specific examples of thermoplastic resins include cyclic polyolefin resins, polyolefin resins, polyester resins, polyamide resins, acrylonitrile butadiene styrene resins, polycarbonate resins, acrylic resins, fluororesins, vinyl chloride resins, polymethylpentene resins, and tetrafluoroethylene resins. The use of these resins makes it easier to increase the tensile elongation at break.

[0055] Cyclic polyolefin resins are polymers containing structural units derived from cyclic olefins. Examples of cyclic olefins include tetracyclododecene, norbornene, and cyclic conjugated dienes. The cyclic polyolefin resins may be polymers of cyclic olefins, copolymers of cyclic olefins and α-olefins, or hydrogenated products thereof. Examples of the α-olefins include linear α-olefins having from 1 to 12 carbon atoms, such as ethylene, propylene, butene-1, pentene-1, hexene-1, heptene-1, and octene-1. Of these, ethylene is preferred.

[0056] The polyolefin resin is a polyolefin resin other than a cyclic polyolefin resin, and specific examples thereof include polypropylene resin, polyethylene resin, etc. Among these, polypropylene resin is preferred. The polypropylene resin may be homopropylene or a copolymer of propylene, such as random polypropylene, with a small amount (for example, 10% by mass or less) of another α-olefin. Examples of the other α-olefin include linear α-olefins having from 1 to 12 carbon atoms, such as ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, and 1-decene. The polyethylene resin is low-density polyethylene (LDPE, density: 0.930 g / cm 3 less than 0.930 g / cm), medium density polyethylene (MDPE, density: 0.930 g / cm 3 More than 0.942g / cm 3 less than 0.942 g / cm 3 or more), linear low-density polyethylene (LLDPE), etc.

[0057] The polyester resin is not particularly limited, but may be polybutylene terephthalate (PBT) resin. The polybutylene terephthalate resin may be a homopolymer consisting of terephthalic acid units and 1,4-butanediol units, or may be a copolymer containing units derived from copolymerization components other than terephthalic acid units and 1,4-butanediol units. The other copolymerization components may include diol components and dicarboxylic acid components, and may be contained in a proportion of, for example, 30 mol % or less of all units constituting the copolymer.

[0058] The resin film may be a single-layer film consisting of one single layer, or may be a multilayer film consisting of two or more layers. Furthermore, in the resin film constituting the transfer layer, the resin contained in the resin film may be used alone, or two or more types may be used in combination. When two or more types of resins are used in combination, different types of resins may be used in each layer to form a multilayer film. Furthermore, a single-layer film may be formed from a mixture of two or more resins, or one or more layers in a multilayer film may be formed from a mixture of two or more resins.

[0059] Of the above, the resin used in the resin film is preferably one or more resins selected from cyclic polyolefin resins, polyolefin resins, and polyester resins. Among these, one or more selected from cyclic polyolefin resins, polypropylene resins, and PBT resins are more preferred. By using these resins, the solvent resistance of the transfer layer is likely to be increased, and deterioration of the transfer layer can be prevented even if the curable resin composition is diluted with a solvent and directly applied onto the transfer layer. From these viewpoints, the resin used in the resin film is more preferably one or more selected from cyclic polyolefin resins and polypropylene resins, and even more preferably a cyclic polyolefin resin.

[0060] In addition, in the case of a multilayer film, it may be composed of a resin layer (also referred to as a first layer) composed of at least one resin selected from cyclic polyolefin resin, polypropylene resin, and PBT resin, and a resin layer (also referred to as a second layer) composed of a polyolefin resin such as polyethylene resin. For example, a multilayer film in which a first layer serving as a skin layer is provided on one or both sides of the second layer is also preferred. Specifically, a multilayer film in which a first layer composed of PBT resin is provided on one or both sides of a second layer composed of polyethylene resin is preferred. In this case, it is more preferable that a first layer (skin layer) is provided on both sides of the second layer (core layer). Note that when a first layer is provided on only one side of the second resin layer, it is preferable that the first layer is disposed on the paint layer side.

[0061] Each layer in the transfer layer may contain additives other than the resin. Known additives that are incorporated into resin films may be used as the additives. Specific additives include nucleating agents, fluorescent whitening agents, antioxidants, stabilizers, UV absorbers, surfactants, lubricants, fillers, crosslinking agents, crosslinking accelerators, antistatic agents, flame retardants, dispersants, pigments, dyes, and processing aids.

[0062] The resin film constituting the transfer layer may be a stretched film such as a uniaxially stretched film or a biaxially stretched film, or may be a non-stretched film, but is preferably a non-stretched film. When a stretched film is used, it is preferable to use a stretched film with a low stretch ratio. Using a non-stretched film or a stretched film with a low stretch ratio as the resin film makes it easier to increase the tensile elongation at break. The resin film may be a T-die film extruded through a T-die, or an inflation film.

[0063] 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, a non-silicone-based (organic release agent), or a fluorine-based release agent. When the transfer layer is release-treated, the release-treated surface preferably constitutes the surface on the paint layer side. The release treatment of the transfer layer makes it easier to peel the transfer layer from the paint layer. The thickness of the transfer layer is not particularly limited, but is, for example, 30 μm or more and 300 μm or less, and preferably 50 μm or more and 200 μm or less.

[0064] [Layer composition] 1, the transfer resin sheet 10 includes a paint layer 11 and a transfer layer 12, with the paint layer 11 formed on one side of the transfer layer 12 and the two being integrated together. The paint layer 11 may be laminated directly on the transfer layer 12. The transfer resin sheet 10 may be composed of a paint layer 11 and a transfer layer 12 as shown in FIG. 1, but may also include other layers. For example, as shown in FIG. 2, the transfer resin sheet 10 may include a release film 13, with the release film 13 attached to the surface of the paint layer 11. The release film 13 is not particularly limited as long as it is a known release film, but it may be composed of a resin film, or at least one surface of the resin film may be 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. If the release film 13 is release-treated, it is preferable that the release-treated surface be positioned in contact with the paint layer 11. The release film 13 is preferably peeled from the paint layer 11 and removed from the transfer resin sheet 10 before the transfer resin sheet 10 is attached to the substrate.

[0065] 3, the transfer resin sheet 10 may include a support layer 14, and the support layer 14 may be attached to the surface of the paint layer 11. The support layer 14 may be formed from a resin, rubber, or the like. The surface of the support layer 14 that comes into contact with the paint layer 11 may be release-treated, similar to a release film.

[0066] (Method of manufacturing transfer resin sheet) Although the method for producing the transfer resin sheet in the present invention is not particularly limited, it is preferable to prepare a coating liquid in which a curable resin composition is diluted with a solvent, apply the coating liquid to a transfer layer composed of a resin film or the like, and dry the coating liquid. The coating liquid is not particularly limited, but it may be obtained, for example, by mixing each component constituting the curable resin composition, such as a curable resin, a curing agent, a radical polymerization initiator, a pigment, and other additives, into a solvent.

[0067] Examples of the solvent include ethyl acetate, butyl acetate, toluene, etc., and ethyl acetate is preferred from the viewpoints of ease of obtaining the desired transfer resin sheet, workability, etc. The amount of the solvent used is not particularly limited, but is, for example, from 50 parts by mass to 1,000 parts by mass, preferably from 100 parts by mass to 500 parts by mass, relative to 100 parts by mass of the curable resin such as a (meth)acrylic resin.

[0068] The method for applying the coating liquid to the transfer layer is not particularly limited, and it is preferable to apply the coating liquid to the transfer layer using a known coating device.

[0069] 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.

[0070] 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, preventing the solvent from evaporating and causing bubbles when the coating layer is cured. Furthermore, when the drying temperature is equal to or lower than the upper limit, 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, preventing the solvent from evaporating and causing bubbles when the coating layer is cured. 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.

[0071] Furthermore, the dried transfer resin sheet may be subjected to initial curing as needed. Initial curing refers to curing the curable resin composition constituting the paint layer to a semi-cured state. Initial curing may be performed by heating, by irradiation with active energy rays, or by moisture. When performing initial curing by heating, it is recommended to perform the initial curing 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.

[0072] (How to use the transfer resin sheet) The transfer resin sheet of the present invention is used to form a coating on various articles (subjects to be coated). Specifically, after attaching the transfer resin sheet to various subjects to be coated, the paint layer is cured, and the cured paint layer is used as the coating. The transfer layer is preferably peeled off from the paint layer attached to the subject to be coated and removed from the subject to be coated.

[0073] The object to be painted with the transfer resin sheet is not particularly limited, but examples thereof include electrical appliances. Other examples include vehicle interior materials such as automobile and railcar interior materials, vehicle exterior materials such as automobile and railcar exterior materials, and miscellaneous goods. Further examples include exterior materials for heavy machinery, ships, and aircraft, exterior walls and roofing materials for houses and buildings, as well as bridges, steel frames, plants, and wind power generation blades. 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, and rear gates. When the transfer 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 object to be coated 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 the object to be coated by insert molding, and painting with a resin sheet is difficult, but by using the transfer resin sheet of the present invention, such materials can be easily painted.

[0074] The method for attaching the transfer resin sheet to the substrate is not particularly limited, and may be performed by hand using a squeegee or the like, or by 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 transfer 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.

[0075] The transfer resin sheet may be pre-shaped by vacuum forming, press forming, compressed air forming, or the like to form a shape corresponding to the shape of the object to be coated, and then attached to the object to be coated. When pre-shaping is performed, the curable resin sheet is preferably pre-shaped in a state in which a support layer 14 is attached to a paint layer 11, as shown in Figure 3. Pre-shaping is performed by using a jig to shape the transfer resin sheet into a certain shape, but pre-shaping the transfer resin sheet while it has a support layer can prevent the paint layer from sticking to the jig. Among the above methods, pre-shaping is preferably performed by vacuum molding. The pre-shaped transfer resin sheet may be attached to the object to be coated after the support layer is removed. In this case, the transfer resin sheet may be attached by hand, may be attached to the object to be coated using a laminating device, or may be attached by other methods.

[0076] The transfer resin sheet attached to the substrate as described above may have the paint layer cured. When the curable resin composition is heat-curable, the paint layer may be cured by heating. When curing by heating, the heating temperature is not particularly limited as long as the paint 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.

[0077] In addition, when the curable resin composition can be cured by active energy rays, the coating layer may be cured by irradiating the active energy rays. As the active energy rays, ultraviolet rays (UV) are preferably used in terms of curability and convenience. The irradiation dose of the active energy rays is not particularly limited, but may be, for example, 200 mJ / cm. 2 More than 5000mJ / cm 2 Less than or equal to 500 mJ / cm 2 More than 2000mJ / cm 2 The following is the result. In addition, when the curable resin composition can be cured by moisture, it is preferable to carry out curing by moisture.

[0078] The transfer resin sheet has good vacuum formability due to the transfer layer having tensile breaking strength. Therefore, it is preferable to attach the transfer resin sheet to the object to be coated by vacuum forming. It is also preferable to pre-shape the sheet by vacuum forming before attaching it to the object to be coated. Hereinafter, with reference to FIG. 4, a method of attaching the transfer resin sheet to the object to be coated by vacuum forming and forming a coating on the object to be coated will be described in more detail.

[0079] First, the object 20 to be coated is prepared, and the transfer resin sheet 10 is attached to the object 20 by vacuum forming, as shown in Figures 4(a) and 4(b). At this time, the transfer resin sheet 10 is attached to the object 20 to be coated so that the paint layer 11 is in contact with the object 20 to be coated. The transfer resin sheet 10 is also preferably adhered to the object 20 to be coated while being stretched and shaped to fit the shape of the object 20 by vacuum forming. Here, the vacuum forming is preferably TOM forming. TOM stands for "Three Dimension Overlay Method," and by applying TOM forming, the transfer resin sheet 10 can be adhered to the surface of the object 20 to be coated, even if the surface has a complex shape, so as to conform to the shape of the object.

[0080] Figure 5 shows a schematic diagram of an apparatus for performing TOM molding. A transfer resin sheet 10 is set in a TOM molding apparatus 30, with an upper box 31 above the transfer resin sheet 10 and a lower box 32 below the transfer resin sheet 10. Inside the lower box 32, an object 20 to be coated is placed on a vertically movable table 35. The transfer resin sheet 10 has the paint layer on the lower side and the transfer layer on the upper side. In this state, the upper box 31 and the lower box 32 are depressurized, and the transfer resin sheet 10 is heated by a near-infrared heater or the like. Next, the object 20 to be coated is raised by the vertically-lifting table 35, and the object 20 and the transfer resin sheet 10 are pressure-bonded together. Thereafter, compressed air is introduced only into the upper box 11, and this is held for a certain period of time, thereby attaching the transfer resin sheet 10 to the surface of the object 20 to bond the transfer resin sheet 10 onto the object 20 to be coated. Of course, vacuum forming other than TOM forming may also be applied.

[0081] After the transfer resin sheet 10 is attached to the object 20, the paint layer 11 is then cured as shown in Figure 4(c), and the cured paint layer 11 forms a coating on the object 20. The paint layer 11 may be cured by heating, by irradiation with active energy rays, or by moisture. Details of the heating and active energy ray irradiation conditions are as described above. Thereafter, as shown in Figure 4(d), the transfer layer 12 may be peeled off from the paint layer 11 and removed from the object to be coated 20. However, the transfer layer 12 may also be peeled off from the paint layer 11 before curing and removed from the object to be coated 20. Furthermore, as shown in Figure 4(d), the paint layer 11 may be so-called trimmed, that is, unnecessary portions may be cut off as appropriate.

[0082] Next, with reference to Figure 6, an example of a method for forming a coating using a transfer resin sheet that has been pre-shaped by vacuum forming will be described in detail. When pre-shaping is performed, as shown in Figure 6(a), for example, a transfer resin sheet 10 having a support layer 14, with the support layer 14 attached to the surface of a paint layer 11, is prepared, and a jig 40 is also prepared. The surface 40A of the jig 40 should preferably have a shape that matches the surface shape of the object 20 to be coated. The jig 40 may be made of any material, and may be formed from a resin material or a metal.

[0083] The transfer resin sheet 10 having the support layer 14 is placed on the jig 40 so that the support layer 14 faces the surface 40A of the jig 40. As shown in FIG. 6(b), the transfer resin sheet 10 is brought into close contact with the jig 40 by vacuum forming, and the transfer resin sheet 10 is stretched and shaped into a shape corresponding to the surface shape of the object 20 to be coated. The vacuum forming conditions are as described above. Furthermore, the vacuum forming is preferably performed by TOM molding, but may also be performed by a method other than TOM molding. The specific method of TOM molding is as described above, but it is preferable to place the jig 40 in the TOM molding device 30 instead of the object 20 to be coated. The transfer-type resin sheet 10 preliminarily shaped as shown in FIG. 6(b) may be subjected to so-called trimming, that is, unnecessary portions may be cut off as appropriate. The pre-shaped transfer resin sheet 10 is then removed from the jig 40 as shown in FIGS. 6(b) and 6(c), and the support layer 14 is preferably removed from the transfer resin sheet 10.

[0084] The transfer resin sheet 10 that has been pre-shaped and from which the support layer 14 has been removed is attached to the object 20 to be coated, as shown in Figure 6(c). Here, the method for attaching the transfer resin sheet 10 to the object 20 to be coated is not particularly limited, and it may be attached by hand using a squeegee or the like, or by lamination using a laminating device. The transfer resin sheet 10 has been pre-shaped to a shape corresponding to the surface shape of the object 20 to be coated, so it can be easily attached to the object 20 to be coated even by hand attachment or the like.

[0085] After the transfer resin sheet 10 is attached to the object 20, the paint layer 11 is then cured as shown in FIG. 6(d), forming a coating on the object 20. The paint layer 11 may be cured by heating, by irradiation with active energy rays, or by moisture. Details of the heating and active energy ray irradiation conditions are as described above. The transfer layer 12 may also be peeled off from the paint layer 11 and removed from the object 20. The transfer layer 12 may be removed before the paint layer 11 is cured, but is preferably removed after curing. [Example]

[0086] 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.

[0087] The measurement and evaluation methods in the present invention are as follows.

[0088] <Tack value of paint layer> The tack value of the paint layer was measured as follows. Specifically, the coating transfer curable resin was set in a probe tack tester (TA-500 manufactured by UBM Corporation) so that the applied surface was in contact with the probe. Measurement was carried out under the following conditions, and the maximum load required for peeling was evaluated as the tack value. Probe diameter: 5 mm, speed: 10 mm / s, contact load: 100 gf, contact time: 1 s

[0089] <Tensile elongation at break of transfer layer> The tensile elongation at break of the transfer layer was measured by a measurement method conforming to JIS K7127. Specifically, the film used for the transfer layer was cut into a dumbbell shape with a width of 10 mm and a gauge width of 25 mm, and then attached to a tensile tester. In Examples 1 to 8 and Comparative Examples 1 and 2, the film was pulled in a thermostatic chamber set at 120°C at a pulling speed of 100 mm / min, and the tensile elongation was calculated from the displacement at the point where the film broke using the following formula. In addition, in Examples 9 to 12 and Comparative Examples 3 and 4, the film was pulled in a thermostatic chamber set at 100°C at a pulling speed of 100 mm / min, and the tensile elongation was calculated from the displacement at the point where the film broke using the following formula. The jig width was the same as the gauge width. The tensile elongation at break of the transfer layer was measured in both MD and TD. Tensile elongation (%) = (displacement at break / gauge width) x 100

[0090] <Scratch resistance> The measurement was carried out using pencil scratching in accordance with JIS K5600-5-4. Specifically, a measurement sample was prepared as follows: In Example 7, the prepared transfer resin sheet was attached to a baked painted board, and then exposed to 3000 mJ / cm 2 using an ultraviolet irradiation device with a 365 nm LED lamp. 2 After curing under the conditions, the transfer film was peeled off to prepare an evaluation sample. In all cases except for Example 7, the transfer resin sheet was attached to a baked painted plate, the transfer film was peeled off, the paint layer was transferred to the baked painted plate, and the baked painted plate was then placed in an oven at 160°C for 1 hour to be thermally cured. A 1 kg load was applied to the surface of the cured paint layer at a 45° angle with a pencil, scratching it 10 mm, and the degree of scratching was checked and the hardest pencil hardness that did not leave a scratch was indicated. The pencil used was the "Mitsubishi Pencil uni (manufactured by Mitsubishi Pencil Co., Ltd.) certified by the Japan Paint Inspection Association." <Adhesion> The adhesiveness was evaluated as follows. First, water containing 0.5% polyalkyl ether surfactant was sprayed onto the baked painted board. Next, the transfer resin sheet was placed so that the adhesive surface overlapped the baked painted board, and then the transfer layer was rubbed with a squeegee to remove the water and press the sheet together. After pressing, the adhesiveness was evaluated based on the peeling behavior when the transfer layer was peeled off. A: There was no lifting or peeling of the paint layer, and it was able to be applied successfully. B: The paint layer was peeling and could not be applied properly.

[0091] <Vacuum formability> The transfer resin sheets produced in the examples and comparative examples were evaluated for vacuum formability by TOM molding as shown below. A coating object (Test Piece Car Shape, manufactured by ASONE) was placed on a vertically adjustable table installed in a TOM molding machine (manufactured by Fuse Vacuum Co., Ltd., product name "NGF-0709-S") consisting of an upper box and a lower box. Then, a curable resin sheet was set in a sheet clamp frame installed in the molding machine with the coating layer on the bottom and the transfer layer on the top. The upper and lower boxes were then depressurized to a gauge pressure of 0.0 kPa or less, and the transfer resin sheet was heated until its temperature reached 120°C. However, in Examples 9 to 12 and Comparative Examples 3 and 4, the transfer resin sheet was heated until its temperature reached 100°C. The coating object was then elevated to pressurize the coating object and the transfer resin sheet together. Compressed air was then introduced only into the upper box, and the pressure was maintained for 5 seconds. The upper and lower boxes were then released to atmospheric pressure, yielding a laminate consisting of the coating object and the transfer resin sheet. The resulting laminate was observed and evaluated for vacuum formability according to the following criteria. A: The transfer resin sheet conformed to the three-dimensional shape of the object to be coated and adhered evenly. B: The transfer resin sheet was unable to conform to the three-dimensional shape of the object to be coated, causing the sheet to break, or the entire sheet to wrinkle. -: The transfer resin sheet was deformed and could not be fixed with the sheet clamp of the molding machine, so evaluation was not possible.

[0092] The components used in the examples and comparative examples and the films used for the transfer layer are as follows. <(Meth)acrylic resin (A) and plasticizing resin (a)> The acrylic polyol, the reactive polymer containing an acroyl group, and the polycarbonate diol used were those listed in Table 1 below. [Table 1]

[0093] <Blocked isocyanate (B)> Hexamethylene diisocyanate-based blocked isocyanate (HDI-based), Mitsui Chemicals' "Takenate B-882N", blocking agent type: 2-butanone oxime (MEKO), NV=70%, solvent: petroleum naphtha, contains a small amount of urethane catalyst <Photoradical polymerization initiator (C)> Acetophenone compound, BASF "Omnirad1173" (NV = 100% by mass) <Pigment (D)> Pigment dispersion: NSP-UP 841B manufactured by Nihon Bix Co., Ltd., effective pigment concentration = 9% by mass, NV = 24% by mass

[0094] <Transfer layer film> Unstretched cyclic polyolefin film (Toray Industries, Inc. "Decofit Q16CK", thickness 100 μm) Unstretched multilayer polybutylene terephthalate film Unstretched multilayer olefin film 1 (Okamoto "Convenience Store PP", thickness 100 μm) Unstretched multilayer olefin film 2 (Okamoto "Convenience Store PE", thickness 100 μm) Unstretched polyethylene terephthalate film ("Kanelon KA-20" manufactured by Shinei Kasei Co., Ltd., thickness 100 μm) Biaxially oriented polyethylene terephthalate film (Toyobo Co., Ltd. "Cosmo Peel E7004")

[0095] [Example 1] According to the formulation shown in Table 2, 71 parts by mass of acrylic polyol (A1), 9 parts by mass of acrylic polyol (a1-(1)), and 20 parts by mass of blocked isocyanate (B) were mixed with thorough stirring to prepare a coating liquid of a curable resin composition. This coating liquid was applied with an applicator to the smooth surface of an unstretched cyclic polyolefin film ("Decofit Q16CK" manufactured by Toray Industries, Inc.) that constituted the transfer layer. A pre-drying process was then carried out at a drying temperature of 60°C for 30 minutes, followed by a main drying process at a drying temperature of 90°C for 30 minutes, yielding a transfer resin sheet with a 50 μm thick coating layer formed on the transfer layer. During this drying process, the solvent was removed from the coating liquid, and the resulting coating layer had the composition shown in Table 3.

[0096] [Examples 2 to 5, 7 to 8, Comparative Examples 1 to 2] A transfer resin sheet was obtained in the same manner as in Example 1, except that the formulation of the curable resin composition used in the coating liquid and the film used in the transfer layer were changed as shown in Table 2. In Example 5, the pigment shown in Table 1 was also added to produce a transfer resin sheet.

[0097] [Example 6] A transfer-type curable resin sheet for coating was produced in the same manner as in Example 1, except that an unstretched multilayer polybutylene terephthalate film was used as the transfer layer film and the formulation of the curable resin composition used in the coating liquid was changed as shown in Table 2. The unstretched multilayer polybutylene terephthalate film was produced as follows. The raw material for the skin layer was prepared as follows: 100 parts by mass of polybutylene terephthalate resin (manufactured by Mitsubishi Engineering Plastics Corporation, trade name "Novaduran 5010CS") and 100 parts by mass of a crystal nucleating agent (bis(4-methylbenzylidene) sorbitol, T m = 200°C (manufactured by New Japan Chemical Co., Ltd., product name: Gelall E-200) at a composition ratio of 5 parts by mass, and then melt-kneaded and pelletized using a twin-screw extruder at a cylinder temperature of 250°C to produce a nucleating agent masterbatch with a nucleating agent concentration of 5% by mass. Next, a blend of the polybutylene terephthalate and the nucleating agent masterbatch described above was used as the raw material. The amount of nucleating agent added was 3 parts by mass of the nucleating agent masterbatch per 100 parts by mass of polybutylene terephthalate, i.e., the amount of nucleating agent added was 1500 ppm. The raw material for the core layer was a high density polyethylene resin (Novatec HD, manufactured by Japan Polyethylene Corporation). Using a three-layer T-die film molding machine equipped with three extruders with a screw diameter of 40 mm, each raw material was charged into each extruder, and a two-type, three-layer, unstretched polybutylene terephthalate film (multilayer PBT film, thickness 200 μm) was obtained under conditions of a molding temperature of 250°C, a chill roll temperature of 80°C, and an air chamber static pressure of 15 mmH2O, with both skin layers being 50 μm thick PBT resin layers and a core layer being a 90 μm thick polyethylene resin layer.

[0098] [Example 9] A transfer resin sheet was prepared in the same manner as in Example 1, except that the tensile breaking elongation of the transfer layer was measured at 100°C, unstretched multilayer olefin film 1 ("Convenience Store PP" manufactured by Okamoto Corporation, thickness 100 μm) was used as the transfer layer film, and the main drying process (drying temperature 90°C, drying time 30 minutes) was not performed.

[0099] [Example 10] A transfer resin sheet was produced in the same manner as in Example 2, except that the tensile breaking elongation of the transfer layer was measured at 100°C, unstretched multilayer olefin film 2 ("Convenience PE" manufactured by Okamoto Corporation, thickness 100 μm) was used as the transfer layer film, and the main drying process (drying temperature 90°C, drying time 30 minutes) was not performed.

[0100] [Example 11] A transfer resin sheet was produced in the same manner as in Example 3, except that the tensile breaking elongation of the transfer layer was measured at 100°C, an unstretched polyethylene terephthalate film ("Kanelon KA-20" manufactured by Shin-ei Kasei Co., Ltd., thickness 100 μm) was used as the transfer layer film, and the main drying process (drying temperature 90°C, drying time 30 minutes) was not performed.

[0101] [Example 12] A transfer resin sheet was produced in the same manner as in Example 1, except that the tensile breaking elongation of the transfer layer was measured at 100°C, a biaxially oriented polyethylene terephthalate film (Cosmo Peel E7004 manufactured by Toyobo Co., Ltd.) was used as the transfer layer film, and the formulation of the curable resin composition used in the coating liquid was changed as shown in Table 3.

[0102] Comparative Example 3 A transfer resin sheet was prepared in the same manner as in Comparative Example 1, except that an unstretched multilayer olefin film 1 (Okamoto Corporation's "Convenience Store PE", thickness 100 μm) was used as the transfer layer film, the tensile breaking elongation of the transfer layer was measured at 100°C, and the main drying process (drying temperature 90°C, drying time 30 minutes) was not performed.

[0103] Comparative Example 4 A transfer resin sheet was prepared in the same manner as in Comparative Example 2, except that an unstretched multilayer olefin film 1 ("Convenience PE" manufactured by Okamoto Corporation, thickness 100 μm) was used as the transfer layer film, the tensile breaking elongation of the transfer layer was measured at 100°C, and the main drying process (drying temperature 90°C, drying time 30 minutes) was not performed.

[0104] [Table 2]

[0105] [Table 3]

[0106] Table 4 below shows the content of each component based on the total solid content of the curable resin composition in Examples 1 to 8 and Comparative Examples 1 and 2. However, the amount of the active ingredient in the pigment in Example 5 was 2 mass % based on the total solid content of the curable resin composition.

[0107] [Table 4]

[0108] In each of the above examples, a transfer resin sheet with excellent scratch resistance and adhesion could be produced by keeping the tack value of the application surface side of the paint layer within a certain range at 23° C. Furthermore, in Examples 1 to 7 and 9 to 11, a transfer layer with high tensile elongation at break at 120° C. or 100° C. was used, which resulted in good vacuum formability and allowed the transfer resin sheet to conform to the three-dimensional shape of the object to be coated and to adhere uniformly, and an appropriate coating could be formed from the resin sheet using vacuum forming. In contrast, in Comparative Examples 1 and 3, the tack value of the paint layer on the application surface at 23°C was low, resulting in insufficient adhesive strength to the adherend and inability to adhere well. Also, in Comparative Examples 2 and 4, the tack value of the paint layer on the application surface at 23°C was high, resulting in insufficient hardness and therefore poor scratch resistance. [Explanation of symbols]

[0109] 10 Transferable curable resin sheet for painting 11 Paint layer 12 Transfer layer 13 Release film 14 Support layer 20 Object to be painted 30 TOM forming equipment 31 Upper Box 32 Lower Box 35 Height-adjustable table 40 Jig

Claims

1. A transfer-type curable resin sheet for coating, comprising a paint layer containing a curable resin composition that can be cured by heat, moisture, or active energy rays, and a transfer layer containing a thermoplastic resin, The tack value of the paint layer at 23°C on the surface opposite to the surface on which the transfer layer is provided is 300 N / cm ２ More than 4000N / cm ２ The following is a transfer-type curable resin sheet for painting.

2. 2. The transfer-type curable resin sheet for coating according to claim 1, wherein the transfer layer has a tensile elongation at break of 500% or more in both MD and TD at 120°C.

3. 3. The transfer-type curable resin sheet for coating according to claim 1, wherein the transfer layer has a tensile elongation at break of 500% or more in both MD and TD at 100°C.

4. 3. The transfer-type curable resin sheet for coating according to claim 1, wherein the curable resin composition comprises a (meth)acrylic resin (A) that has a weight average molecular weight of 100,000 or more and 1,000,000 or less, is solid, and has a plurality of functional groups.

5. the (meth)acrylic resin (A) is a (meth)acrylic polyol (A1), The transfer-type curable resin sheet for coating according to claim 4 , wherein the curable resin composition contains a blocked isocyanate (B).

6. the (meth)acrylic resin (A) is a polymer (A2) having a (meth)acryloyl group, The transfer-type curable resin sheet for coating according to claim 4, further comprising a radical polymerization initiator (C) that generates radicals when exposed to heat or active energy rays.

7. A method for forming a coating, comprising attaching the transfer-type curable resin sheet for coating according to claim 1 or 2 to an object to be coated, and then curing the paint layer to form a coating.

8. The method for forming a coating according to claim 7, further comprising peeling the transfer layer from the paint layer to remove the transfer layer from the object to be coated.

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