Coating method, application liquid, set of application liquid and coating sheet, vehicle, vehicle part, and member

Abstract

To provide a coating method, an application liquid, a set of the application liquid and a coating sheet, and a coated vehicle, vehicle part, and member, which are capable of preventing blister formation upon heating of the coating sheet, following bonding of the coating sheet to a target material using the application liquid, and also capable of suppressing dissolution of the paint layer of the coating sheet caused by the application liquid.SOLUTION: The present invention provides a coating method for applying a coating to a target material 100, wherein the method comprises: an application liquid coating step in which an application liquid 1 is applied to the target material 100, the application liquid 1 containing at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, cyclic esters, glycol ethers, glycol esters, glycerin, glycols, and water-soluble gelling agents, and water, and wherein the content of the compound is within a predetermined range; a sheet attaching step in which a coating sheet 2 is attached to a surface of the target material 100 which has been coated with the application liquid 1; and a curing step in which the target material 100 with the attached coating sheet 2 is heated to cure the coating sheet 2.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a coating method, a coating liquid, a set of the coating liquid and a coating sheet, and a vehicle, a vehicle part, and a member coated by the coating method. [Background technology]

[0002] Furniture, steel plates, vehicle bodies, and the like are painted or decorated from the viewpoint of design and durability. It is known that decoration is performed using a decorative film such as a painted sheet. The painted sheet is generally provided with a paint layer.

[0003] In order to attach the adhesive film to the adherend without air bubbles, an application liquid is used. For example, the application liquid is sprayed onto the surface of the adherend to which the adhesive film is to be attached using a spray or the like, thereby wetting the surface of the adherend to which the adhesive film is to be attached. Then, in a state where the surface of the adherend to which the adhesive film is to be attached is wet with the application liquid, the adhesive sheet is applied to the adherend, and air bubbles and air are pushed out together with the application liquid between the adherend and the adhesive film by a squeegee or the like, so that the adhesive film can be neatly attached to the adherend.

[0004] As working liquids used for attaching adhesive films, for example, the working liquids described in Patent Documents 1 to 3 are known as prior art (see Patent Documents 1 to 3). The working liquids described in Patent Documents 1 and 2 are water (or water only) that does not contain an additive that imparts slipperiness, such as a surfactant, or water that contains an additive that imparts slipperiness, such as a surfactant. The working liquid described in Patent Document 3 is water that contains a surfactant. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-140378 A [Patent Document 2] International Publication No. 2016 / 135997 Brochure [Patent Document 3] JP 2014-145034 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, it is difficult to completely push out the application liquid between the adherend and the adhesive film using a squeegee or the like. Therefore, when a conventional application liquid is used to attach a coating sheet, when the coating sheet is heated to harden after being attached to the coating object, the application liquid remaining between the coating sheet and the coating object may evaporate, causing swelling. In addition, when a conventional application liquid is used to attach a coating sheet, the paint layer of the coating sheet may dissolve into the application liquid.

[0007] Therefore, an object of the present invention is to provide a coating method that can suppress the occurrence of blistering when a coating sheet is heated after being attached to an object to be coated using an application liquid, and that can suppress dissolution of the paint layer of the coating sheet by the application liquid, an application liquid, a set of the application liquid and a coating sheet, and vehicles, vehicle parts and members coated by the coating method. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by using a specific compound as an additive to a water-based working liquid, and have thus completed the present invention. [1] A coating method for applying a coating to an object to be coated, comprising the steps of: a liquid application step of applying a liquid to the object to be coated, the liquid containing water and at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, the compound content of which is 0.05 to 55 mass %; a sheet application step of applying a coating sheet having a coating layer made of a thermosetting resin composition to the surface of the object to be coated on which the application liquid has been applied; and a curing step of heating the object to which the coating sheet is attached to cure the coating sheet. [2] A coating method for applying a coating to an object to be coated, comprising the steps of: a liquid application step of applying to the substrate a liquid containing water and at least one compound selected from the group consisting of glycol ethers, glycol esters and glycerin, the compound content of which is 0.05 to 65 mass %; a sheet application step of applying a coating sheet having a coating layer made of a thermosetting resin composition to the surface of the object to be coated on which the application liquid has been applied; and a curing step of heating the object to which the coating sheet is attached to cure the coating sheet. [3] A coating method for applying a coating to an object to be coated, comprising the steps of: a liquid application step of applying a liquid containing glycols and water, the glycols being present in an amount of 0.05 to 90% by mass, to the object to be coated; a sheet application step of applying a coating sheet having a coating layer made of a thermosetting resin composition to the surface of the object to be coated on which the application liquid has been applied; and a curing step of heating the object to which the coating sheet is attached to cure the coating sheet. [4] A coating method for applying a coating to an object to be coated, comprising the steps of: a liquid application step of applying a liquid containing a water-soluble gelling agent and water, the water-soluble gelling agent being present in an amount of 0.05 to 10 mass % to the object to be coated; a sheet application step of applying a coating sheet having a coating layer made of a thermosetting resin composition to the surface of the object to be coated on which the application liquid has been applied; and a curing step of heating the object to which the coating sheet is attached to cure the coating sheet. [5] The coating method according to the above [4], wherein the water-soluble gelling agent is at least one compound selected from the group consisting of sodium polyacrylate, sodium carboxymethylcellulose and sodium alginate. [6] The coating method according to any one of the above [1] to [5], wherein the thermosetting resin composition contains a (meth)acrylic resin and a blocked isocyanate curing agent. [7] The weight average molecular weight of the (meth)acrylic resin is 50,000 or more and 1,000,000 or less, The coating method according to the above item [6], wherein the (meth)acrylic resin contains a (meth)acrylic resin having a plurality of functional groups. [8] The coating method according to the above [6] or [7], wherein the (meth)acrylic resin is a (meth)acrylic polyol. [9] The coating method according to any one of the above [1] to [8], wherein the paint layer comprises a clear layer and a colorant layer.

[10] The coating sheet further comprises a transfer layer, The coating method according to any one of the above [1] to [9], further comprising a transfer layer removing step of removing the transfer layer from the coating sheet before the curing step.

[11] A coated sheet having a paint layer and a transfer layer made of a thermosetting resin composition; and an application liquid used when attaching the coating sheet to an object to be coated, The working liquid contains water and at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, A set of an application liquid and a coating sheet, wherein the content of the compound in the application liquid is 0.05 to 55 mass %.

[12] A coated sheet having a paint layer and a transfer layer made of a thermosetting resin composition; and an application liquid used when attaching the coating sheet to an object to be coated, The working liquid contains water and at least one compound selected from the group consisting of glycol ethers, glycol esters, and glycerin, A set of an application liquid and a coating sheet, wherein the content of the compound in the application liquid is 0.05 to 65 mass %.

[13] A coated sheet having a paint layer and a transfer layer made of a thermosetting resin composition; and an application liquid used when attaching the coating sheet to an object to be coated, The working liquid contains glycols and water, A set of an application liquid and a coating sheet, wherein the content of the glycols in the application liquid is 0.5 to 90 mass %.

[14] A coated sheet having a paint layer and a transfer layer made of a thermosetting resin composition; and an application liquid used when attaching the coating sheet to an object to be coated, The application liquid contains a water-soluble gelling agent and water, A set of an application liquid and a coating sheet, wherein the content of the water-soluble gelling agent in the application liquid is 0.05 to 10% by mass.

[15] A set of a coating fluid and a coated sheet according to the above

[14] , wherein the water-soluble gelling agent is at least one compound selected from the group consisting of sodium polyacrylate, sodium carboxymethylcellulose and sodium alginate.

[16] A coating liquid used when attaching a coating sheet to an object to be coated, The composition contains at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, and water, The content of the compound in the working liquid is 0.05 to 55% by mass.

[17] A coating liquid used when attaching a coating sheet to an object to be coated, The composition comprises water and at least one compound selected from the group consisting of glycol ethers, glycol esters, and glycerin, The content of the compound in the working liquid is 0.05 to 65% by mass.

[18] A coating liquid used when attaching a coating sheet to an object to be coated, Contains glycols and water, The working liquid has a content of the glycols of 0.05 to 90% by mass.

[19] A coating liquid used when attaching a coating sheet to an object to be coated, Contains a water-soluble gelling agent and water, The working liquid has a content of the water-soluble gelling agent of 0.05 to 10% by mass.

[20] The working liquid according to the above

[19] , wherein the water-soluble gelling agent is at least one compound selected from the group consisting of sodium polyacrylate, sodium carboxymethylcellulose and sodium alginate.

[21] A vehicle painted by the painting method described in any one of [1] to

[10] above.

[22] A vehicle part coated by the coating method according to any one of [1] to

[10] above.

[23] A member coated by the coating method described in any one of [1] to

[10] above. Effect of the Invention

[0009] According to the present invention, it is possible to provide a coating method, an application liquid, and a set of the application liquid and the coating sheet, which can suppress the occurrence of blistering when the coating sheet is heated after being attached to an object to be coated, and which can suppress dissolution of the paint layer of the coating sheet by the application liquid, as well as a vehicle, vehicle part, and member coated by the coating method. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram for explaining the working liquid application step. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing an example of a coated sheet. [Diagram 3] FIG. 3 is a diagram for explaining the sheet attachment step. [Figure 4] FIG. 4 is a diagram for explaining the sheet attachment step. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing another example of the coated sheet. [Figure 6] FIG. 6 is a schematic cross-sectional view showing another example of the coated sheet. [Figure 7] FIG. 7 is a schematic cross-sectional view showing another example of the coated sheet. [Figure 8] FIG. 8 is a schematic cross-sectional view showing another example of the coated sheet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Painting method] Hereinafter, a coating method according to one embodiment of the present invention will be described with reference to the drawings. The coating method according to one embodiment of the present invention is a coating method for applying a coating to an object to be coated, and includes a coating liquid application step, a sheet attachment step, and a curing step. (1) Construction fluid application process As shown in FIG. 1, in the liquid application step, the liquid 1 is applied to an object 100 to be coated.

[0012] (Construction liquid) The working liquid 1 used in the coating application step contains at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, at least one compound selected from the group consisting of glycol ethers, glycol esters, and glycerin, or glycols, and water. When the working liquid 1 contains at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, and water, the content of the above compound is 0.05 to 55 mass%. When the working liquid 1 contains at least one compound selected from the group consisting of glycol ethers, glycol esters, and glycerin, and water, the content of the above compound is 0.05 to 65 mass%. When the working liquid 1 contains glycols and water, the content of the above glycols is 0.05 to 90 mass%. This increases the affinity of the working liquid 1 to the paint layer 10, and the working liquid 1 remaining between the coating sheet 2 and the object to be coated 100 penetrates into the paint layer 10. As a result, when the coating sheet 2 is heated after being attached to the object 100, the coating evaporates without causing foaming, thereby preventing the occurrence of blisters. In addition, the affinity of the application liquid 1 for the paint layer 10 does not become high enough to dissolve the paint layer 10, so dissolution of the paint layer 10 of the coating sheet 2 by the application liquid 1 can be prevented. In another embodiment, the working liquid 1 used in the coating application step contains a water-soluble gelling agent and water. In this case, the content of the water-soluble gelling agent is 0.05 to 10 mass %. As a result, the working liquid 1 remaining between the coating sheet 2 and the object to be coated 100 is gelled by the water-soluble gelling agent, and foaming due to evaporation when heated is suppressed, preventing swelling. In addition, since the solubility of the water-soluble gelling agent in the paint layer 10 is not high, dissolution of the paint layer 10 of the coating sheet 2 by the working liquid 1 can be suppressed.

[0013] <Alcoholic drinks> The alcohols, glycols, glycerin, glycol ethers, glycol esters, ketones, cyclic ethers, and cyclic esters used in the working liquid 1 are water-soluble organic solvents. From the viewpoint of being able to suppress the occurrence of swelling when the coating sheet 2 is heated after the coating sheet 2 is attached to the object to be coated 100 using the working liquid 1 and being able to suppress the dissolution of the coating layer 10 of the coating sheet 2 by the working liquid 1, the alcohols used in the working liquid 1 are preferably alcohols having 1 to 4 carbon atoms, more preferably alcohols having 2 to 3 carbon atoms. Examples of these alcohols include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, and tert-butyl alcohol. These alcohols can be used alone or in combination with two or more types, or in combination with other types of water-soluble organic solvents. Among these alcohols, ethyl alcohol and isopropyl alcohol are preferred.

[0014] <Ketones> Acetone, methyl ethyl ketone, diacetone alcohol, etc. are used as ketones for the working liquid 1 from the viewpoint of being able to suppress the occurrence of blistering when the coating sheet 2 is heated after the coating sheet 2 is attached to the object to be coated 100 using the working liquid 1, and being able to suppress dissolution of the paint layer 10 of the coating sheet 2 by the working liquid 1. These ketones can be used alone, or in combination with two or more kinds, or with other kinds of water-soluble organic solvents. Of these, acetone is preferred.

[0015] <Cyclic ethers and cyclic esters> From the viewpoints of being able to suppress the occurrence of swelling when the coating sheet 2 is heated after the coating sheet 2 is attached to the substrate 100 using the working liquid 1 and being able to suppress dissolution of the paint layer 10 of the coating sheet 2 by the working liquid 1, tetrahydrofuran, 1,4-dioxane, etc. are used as the cyclic ethers used in the working liquid 1, and γ-butyrolactone, etc. are used as the cyclic esters. These cyclic ethers and cyclic esters can be used alone, or in combination with two or more kinds, or with other types of water-soluble organic solvents. Of these, γ-butyrolactone and 1,4-dioxane are preferred.

[0016] <Glycol ethers> From the viewpoints of being able to suppress the occurrence of blistering when the coating sheet 2 is heated after the coating sheet 2 is attached to the substrate 100 using the working liquid 1 and being able to suppress dissolution of the paint layer 10 of the coating sheet 2 by the working liquid 1, preferred glycol ethers used in the working liquid 1 include glycol ethers in which the OH group at one or both ends of ethylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms, glycol ethers in which the OH group at one or both ends of propylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms, glycol ethers in which the OH group at one or both ends of diethylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms, glycol ethers in which the OH group at one or both ends of dipropylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms, glycol ethers in which the OH group at one or both ends of triethylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms, and glycol ethers in which the OH group at one or both ends of tripropylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms. These glycol ethers include, for example, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, ethylene glycol propyl ether, ethylene glycol dipropyl ether, ethylene glycol mono n-butyl ether, ethylene glycol mono tert-butyl alcohol, ethylene glycol di-n-butyl ether, ethylene glycol mono n-hexyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, propylene glycol monoethyl ether, propylene glycol diethyl ether, propylene glycol monopropyl ether, propylene glycol dipropyl ether, propylene glycol methyl ethyl ether, propylene glycol mono n-butyl ether, propylene glycol di-n-butyl ether, propylene glycol mono tert-butyl ether, propylene glycol mono n-hexyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether,Diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol propyl ether, diethylene glycol dipropyl ether, diethylene glycol mono n-butyl ether, diethylene glycol di-n-butyl ether, diethylene glycol mono tert-butyl ether, diethylene glycol mono n-hexyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, dipropylene glycol methyl ethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol dipropyl ether, dipropylene glycol mono n-butyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol mono tert-butyl ether, dipropylene glycol mono n-hexyl ether, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, triethylene glycol monoethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol propyl ether, triethylene glycol dipropyl ether, triethylene glycol mono n-butyl ether, triethylene glycol di n-butyl ether, triethylene glycol mono tert-butyl ether, tripropylene glycol monomethyl ether, tripropylene glycol dimethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol diethyl ether, tripropylene glycol methyl ethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol dipropyl ether, tripropylene glycol mono n-butyl ether, tripropylene glycol di n-butyl ether, tripropylene glycol mono tert-butyl ether, 1-tert-butoxyethanol, 2-tert-butoxyethanol, phenoxyethanol, 3-methoxy-3-methyl-1-butanol, 1-methoxy-2-butanol, 2-methoxy-1-butanol, 2-methoxy-2-methylbutanol,and 2-(2-butoxyethoxy)ethanol. These glycol ethers may be used alone or in combination with two or more water-soluble organic solvents. Among these glycol ethers, ethyl glycol mono-n-butyl ether and propylene glycol monomethyl ether are preferred.

[0017] <Glycol esters> From the viewpoints of being able to suppress the occurrence of blistering when the coating sheet 2 is heated after the coating sheet 2 is attached to the substrate 100 using the working liquid 1 and being able to suppress dissolution of the paint layer 10 of the coating sheet 2 by the working liquid 1, preferred examples of the glycol esters used in the working liquid 1 include glycol esters in which the OH group at one end of ethylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms, glycol esters in which the OH group at one end of propylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms, glycol esters in which the OH group of diethylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms, glycol esters in which the OH group of dipropylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms, glycol esters in which the OH group of triethylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms, and glycol esters in which the OH group of tripropylene glycol is substituted with an alkyl group having 1 to 6 carbon atoms. Examples of glycol esters of ethylene glycol monomethyl ether acetate include ethylene glycol monomethyl ether acetate, ethylene glycol dimethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol diethyl ether acetate, ethylene glycol methyl ethyl ether acetate, ethylene glycol propyl ether acetate, ethylene glycol dipropyl ether acetate, ethylene glycol mono-n-butyl ether acetate, ethylene glycol di-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol dimethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol diethyl ether acetate, propylene glycol methyl ethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol dipropyl ether acetate, propylene glycol mono-n-butyl ether acetate, propylene glycol di-n-butyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol diethyl ether acetate,Diethylene glycol methyl ethyl ether acetate, diethylene glycol propyl ether acetate, diethylene glycol dipropyl ether acetate, diethylene glycol mono n-butyl ether acetate, diethylene glycol di n-butyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol dimethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol diethyl ether acetate, dipropylene glycol methyl ethyl ether acetate, dipropylene glycol monopropyl ether acetate, dipropylene glycol dipropyl ether acetate, dipropylene glycol mono n-butyl ether acetate, dipropylene glycol di n-butyl ether acetate, triethylene glycol monomethyl ether acetate, triethylene glycol Examples of the glycol ethers include dimethyl ether acetate, triethylene glycol monoethyl ether acetate, triethylene glycol diethyl ether acetate, triethylene glycol propyl ether acetate, triethylene glycol dipropyl ether acetate, triethylene glycol mono n-butyl ether acetate, triethylene glycol di n-butyl ether acetate, tripropylene glycol monomethyl ether acetate, tripropylene glycol dimethyl ether acetate, tripropylene glycol monoethyl ether acetate, tripropylene glycol diethyl ether acetate, tripropylene glycol monopropyl ether acetate, tripropylene glycol dipropyl ether acetate, tripropylene glycol mono n-butyl ether acetate, and tripropylene glycol di n-butyl ether acetate. These glycol ethers can be used alone, or in combination with two or more water-soluble organic solvents. Among these glycol ethers, ethyl glycol mono n-butyl ether and propylene glycol monomethyl ether are preferred.

[0018] <Glycerin> Glycerin can be used as the application liquid 1 from the viewpoints that it is possible to suppress the occurrence of swelling when the coating sheet 2 is heated after the coating sheet 2 is attached to the object to be coated 100 using the application liquid 1, and also to suppress dissolution of the paint layer 10 of the coating sheet 2 by the application liquid 1.

[0019] <Glycols> From the viewpoint of being able to suppress the occurrence of swelling when the coating sheet 2 is heated after the coating sheet 2 is attached to the object to be coated 100 using the working liquid 1 and being able to suppress the dissolution of the coating layer 10 of the coating sheet 2 by the working liquid 1, the glycols used in the working liquid 1 are dihydric alcohols, preferably glycols having 2 to 6 carbon atoms. Examples of these glycols include ethylene glycol, 1,3-propanediol, propylene glycol, diethylene glycol, butylene glycol, pentylene glycol, hexylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol. These glycols can be used alone or in combination with two or more types, or in combination with other types of water-soluble organic solvents. Among these glycols, diethylene glycol and dipropylene glycol are preferred.

[0020] <Water-soluble gelling agent> From the viewpoint of being able to suppress the occurrence of swelling when the coating sheet 2 is heated after the coating sheet 2 is attached to the coated object 100 using the application liquid 1 and being able to suppress the dissolution of the coating layer 10 of the coating sheet 2 by the application liquid 1, examples of the water-soluble gelling agent used in the application liquid 1 include sodium polyacrylate, sodium carboxymethylcellulose, sodium alginate, pectin, gelatin, carrageenan, xanthan gum, agar, methylcellulose, HPMC, carob bean gum, glucomannan, gum arabic, gellan gum, etc. These water-soluble gelling agents can be used alone, or in combination with two or more types, or with other types of water-soluble organic solvents. Among these water-soluble gelling agents, sodium polyacrylate, sodium carboxymethylcellulose, and sodium alginate are preferred.

[0021] The water-soluble gelling agent may be used in combination with at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, cyclic esters, glycol esters, glycerin, and glycols.

[0022] <Content of Compound> When the working liquid 1 contains at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, and water, the content of the compound in the working liquid 1 is 0.05 to 55% by mass. If the content of the compound in the working liquid is less than 0.05% by mass, the working liquid remaining between the coating sheet and the substrate after the coating sheet is attached to the substrate using the working liquid may not penetrate into the coating sheet sufficiently, and the coating sheet may blister when heated. If the content of the compound in the working liquid is more than 55% by mass, the coating layer of the coating sheet may be dissolved by the working liquid. From this viewpoint, the content of the compound in the working liquid 1 is preferably 0.1 to 50% by mass, more preferably 10 to 50% by mass.

[0023] When the working liquid 1 contains at least one compound selected from the group consisting of glycol ethers, glycol esters, and glycerin, and water, the content of the compound in the working liquid 1 is 0.05 to 65% by mass. If the content of the at least one compound selected from the group consisting of glycol ethers and glycol esters in the working liquid is less than 0.05% by mass, the working liquid remaining between the coating sheet and the substrate after the coating sheet is attached to the substrate using the working liquid may not penetrate sufficiently into the coating sheet, and the coating sheet may blister when heated. If the content of the at least one compound selected from the group consisting of glycol ethers and glycol esters in the working liquid is more than 65% by mass, the coating layer of the coating sheet may be dissolved by the working liquid. If the content of glycerin in the working liquid is less than 0.05% by mass or more than 65% by mass, the working liquid remaining between the coating sheet and the substrate after the coating sheet is attached to the substrate using the working liquid may not penetrate sufficiently into the coating sheet, and the coating sheet may blister when heated. From this viewpoint, the content of the above compounds in the working liquid 1 is preferably 0.1 to 60 mass %, and more preferably 10 to 60 mass %.

[0024] When the working liquid 1 contains glycols and water, the content of glycols in the working liquid 1 is 0.05 to 90 mass%. If the content of glycols in the working liquid is less than 0.05 mass% or more than 90 mass%, after the coating sheet is attached to the substrate using the working liquid, the working liquid remaining between the coating sheet and the substrate will not penetrate sufficiently into the coating sheet, and the coating sheet may blister when heated. From this viewpoint, the content of glycols in the working liquid 1 is preferably 0.1 to 80 mass%, more preferably 10 to 80 mass%.

[0025] When the working liquid 1 contains a water-soluble gelling agent and water, the content of the water-soluble gelling agent in the working liquid 1 is 0.05 to 10 mass%. If the content of the water-soluble gelling agent in the working liquid is less than 0.05 mass%, the effect of the water-soluble gelling agent in suppressing the evaporation of the coating liquid becomes insufficient, and the coated sheet may blister when heated. If the content of the water-soluble gelling agent in the working liquid is more than 10 mass%, the coating liquid 1 may gel too much, and the applicability of the coating liquid 1 may deteriorate. From this viewpoint, the content of the water-soluble gelling agent in the working liquid 1 is preferably 0.1 to 5 mass%, more preferably 0.2 to 3 mass%.

[0026] When the water-soluble gelling agent is sodium polyacrylate, the content of sodium polyacrylate in the working liquid 1 is preferably 0.1 to 5 mass%, more preferably 0.2 to 3 mass%. When the water-soluble gelling agent is sodium carboxymethylcellulose, the content of sodium carboxymethylcellulose in the working liquid 1 is preferably 0.1 to 5 mass%, more preferably 0.2 to 3 mass%. When the water-soluble gelling agent is sodium alginate, the content of sodium alginate in the working liquid 1 is preferably 0.1 to 5 mass%, more preferably 0.2 to 3 mass%.

[0027] The working liquid 1 contains water as a main solvent, and the water content in the working liquid is, for example, 10 to 99.97 mass %, preferably 15 to 99.95 mass %, and more preferably 20 to 99.9 mass %. Furthermore, the working liquid 1 may contain components other than the above organic solvent and water, and may also contain additives such as surfactants, so long as the effects of the present invention are achieved. Examples of the surfactant include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. Examples of anionic surfactants include fatty acid soaps, alkenyl succinates, sodium alkylbenzene sulfonates, sodium alkylnaphthalene sulfonates, sodium alkyl sulfates, sodium polyoxyethylene alkyl ether sulfates, sodium dialkyl sulfosuccinates, and polycarboxylic acid polymer surfactants. Examples of cationic surfactants include alkyl trimethyl ammonium chloride and alkyl dimethyl benzyl ammonium chloride. Examples of nonionic surfactants include polyoxyalkyl ethers, polyoxyethylene alkyl ethers, polyoxyalkyl allyl ethers, polyoxyethylene alkyl allyl ethers, and sorbitan acid fatty acid esters. Examples of amphoteric surfactants include alkyl betaines and amido betaines. These surfactants can be used alone or in combination of two or more. Among these surfactants, nonionic surfactants are preferred, and polyoxyalkyl ethers are more preferred. The content of the surfactant is not particularly limited, but is, for example, 0.01 to 5 mass %, preferably 0.1 to 2 mass %, based on the total amount of the working liquid.

[0028] (Coating) The method of applying the working liquid 1 to the object 100 to be coated is not particularly limited as long as the surface of the object 100 to be coated can be wetted with the working liquid 1. Examples of methods for applying the working liquid 1 to the object 100 to be coated include brush coating, roll brush coating, pad coating, spray coating, roller coating, curtain flow coating, flow coating, dip coating, spatula coating, etc. Of these coating methods, spray coating is preferred from the viewpoint of coating ability, and spray coating using a spray 50 as shown in Figure 1 is more preferred.

[0029] (Sheet attachment process) As shown in Fig. 3, in the sheet application step, a coating sheet 2 is applied to the surface of an object 100 to be coated that has been coated with the working liquid 1. The sheet application step will be described in detail below with reference to the drawings.

[0030] First, in the sheet attachment step, a painted sheet 2 is prepared as shown in Fig. 2. As shown in Fig. 2, the painted sheet 2 has a paint layer 10.

[0031] (Paint layer) The paint layer 10 is made of a thermosetting resin composition that can be cured by heat. The thermosetting resin composition may contain a curable resin containing a functional group that can be cured by reacting with itself or with a curing agent by heat. Examples of the curable resin used in the thermosetting resin composition include (meth)acrylic resin, polycarbonate resin, polyester resin, and epoxy resin, among which (meth)acrylic resin is preferred.

[0032] The thermosetting resin composition preferably contains a blocked isocyanate curing agent as a curing agent. The blocked isocyanate curing agent is a compound having an isocyanate group, and the details are as described below. By containing the blocked isocyanate curing agent, the thermosetting resin composition can be easily cured by heat.

[0033] In addition, the thermosetting resin composition may contain a functional group reactive to the isocyanate group contained in the blocked isocyanate curing agent, specifically, a hydroxyl group, an amino group, a carboxyl group, etc., among which a hydroxyl group is preferred. The functional group reactive to the isocyanate group is usually contained in the curable resin. The curable resin preferably has a plurality of functional groups in one molecule, and more preferably has a plurality of hydroxyl groups.

[0034] The weight average molecular weight of the curable resin having a functional group reactive to an isocyanate group (hereinafter, sometimes simply referred to as "curable resin") is preferably 50,000 or more and 1,000,000 or less. When the weight average molecular weight of the curable resin is 50,000 or more and 1,000,000 or less, the coating property, curability, tackiness, extensibility, etc. of the paint layer are easily balanced and good. In addition, the coated sheet having the paint layer can be appropriately maintained in a sheet shape. From this viewpoint, the weight average molecular weight of the curable resin is more preferably 60,000 or more and 800,000 or less, even more preferably 70,000 or more and 600,000 or less, and even more preferably 80,000 or more and 600,000 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.

[0035] When the curable resin is a (meth)acrylic resin, the weight average molecular weight of the (meth)acrylic resin is preferably 50,000 or more and 1,000,000 or less. When the weight average molecular weight of the curable resin is 50,000 or more and 1,000,000 or less, the coating property, curability, tackiness, extensibility, etc. of the paint layer can be well balanced and easily achieved. In addition, the coated sheet having the paint layer can be appropriately maintained in a sheet shape. From this viewpoint, the weight average molecular weight of the (meth)acrylic resin is more preferably 60,000 or more and 800,000 or less, even more preferably 70,000 or more and 600,000 or less, and even more preferably 80,000 or more and 600,000 or less. When the curable resin is a (meth)acrylic resin, the (meth)acrylic resin preferably has a plurality of functional groups, and more preferably is a (meth)acrylic polyol having a plurality of hydroxyl groups.

[0036] The coating sheet 2 shown in Fig. 2 is a coating sheet of a preferred embodiment. The coating sheet 2 is an example of a coating sheet used in the coating method of the present invention, and does not limit the coating sheet used in the coating method of the present invention. The coating sheet 2 has a paint layer 10, and the paint layer 10 has a clear layer 11 and a colorant layer 12. The coating sheet 2 of the preferred embodiment will be described in detail below. A coating sheet 2 in a preferred embodiment has, in this order, a clear layer (also referred to as a first resin layer) 11 made of a first thermosetting resin composition and a colorant layer (also referred to as a second resin layer) 12 made of a second thermosetting resin composition. The surface of the coating sheet 2 on the side of the second resin layer 12 is the surface to be attached to an object to be coated.

[0037] (Thermosetting resin composition) The first thermosetting resin composition contains a first curable resin, and the second thermosetting resin composition contains a second curable resin. The first curable resin contained in the first thermosetting resin composition may be the same as or different from the second curable resin contained in the second thermosetting resin composition.

[0038] <Curable resin> The first curable resin and the second curable resin may be selected from (meth)acrylic resin, polycarbonate resin, polyester resin, and epoxy resin as described above, but both are preferably (meth)acrylic resin. The first and second curable resins may contain a functional group reactive to the functional group (isocyanate group) contained in the blocked isocyanate curing agent, specifically, a hydroxyl group, an amino group, a carboxyl group, etc., among which a hydroxyl group is preferred. The first curable resin and the second curable resin may have one functional group, but preferably have two or more. The first curable resin and the second curable resin may have one hydroxyl group, but preferably have two or more. Therefore, both the first curable resin and the second curable resin are preferably (meth)acrylic polyol resins. The weight average molecular weights of the first and second curable resins are as described above. The weight average molecular weights of the first and second curable resins may be the same or different from each other.

[0039] The hydroxyl value of the first curable resin is preferably 50 mgKOH / g or more and 300 mgKOH / g or less. When the hydroxyl value of the first curable resin is 50 mgKOH / g or more, the hardness of the clear layer 11 can be further increased. When the hydroxyl value of the first curable resin is 300 mgKOH / g or less, the adhesive strength of the clear layer 11 to the colorant layer 12 can be further increased. From this viewpoint, the hydroxyl value of the first curable resin is more preferably 60 mgKOH / g or more and 250 mgKOH / g or less, and further preferably 70 mgKOH / g or more and 220 mgKOH / g or less. On the other hand, the hydroxyl value of the second curable resin is preferably 10 mgKOH / g or more and 250 mgKOH / g or less. When the hydroxyl value of the second curable resin is 10 mgKOH / g or more, the strength of the colorant layer 12 can be further increased. If the hydroxyl value of the second curable resin is 250 mgKOH / g or less, it is possible to further increase the adhesive strength of the colorant layer 12 to the coated plate. From this viewpoint, the hydroxyl value of the second curable resin is more preferably 20 mgKOH / g or more and 200 mgKOH / g or less, and further preferably 30 mgKOH / g or more and 180 mgKOH / g or less. In addition, when the first thermosetting resin composition and the second thermosetting resin composition contain a plurality of types of curable resins, the hydroxyl value of the first curable resin and the hydroxyl value of the second curable resin are weighted average values ​​of the hydroxyl values ​​of the curable resins contained in each thermosetting resin composition. For example, when two types of curable resins, curable resin (d1) and curable resin (d2), are used as the curable resin, the hydroxyl value of the curable resin (d1) is X1, the blending ratio is m1, the hydroxyl value of the curable resin (d2) is X2, and the blending ratio is m2, the weighted average value of the hydroxyl value is expressed by the following formula. In addition, the blending ratio is based on mass. Weighted average hydroxyl value (mgKOH / g) = X1 x (m1 / (m1+m2)) + X2 x (m2 / (m1+m2)) The hydroxyl value can be measured in accordance with JISK 1557-1:2007.

[0040] 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 a hydroxyl group. Such an alkyl polymer can contain a hydroxyl group in the acrylic polymer by the hydroxyl group-containing monomer. Note that (meth)acrylic means methacryl or acrylic, and the same applies to other similar terms.

[0041] Examples of the (meth)acrylic acid ester monomer include (meth)acrylic acid ester monomers having no functional group, such as alkyl (meth)acrylates having an alkyl group with a carbon number of about 1 to 18, 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.

[0042] 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.

[0043] The monomer mixture may also contain monomers other than the above-mentioned (meth)acrylic acid ester monomers and hydroxyl group-containing monomers, such as monomers containing functional groups other than hydroxyl groups, and styrene derivative monomers. By using monomers containing functional groups other than hydroxyl groups, such as amino groups and carboxyl groups, in addition to the hydroxyl group-containing monomers, functional groups other than hydroxyl groups can be introduced into the (meth)acrylic resin in addition to the hydroxyl group. 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.

[0044] The (meth)acrylic resin may 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 these monomers.

[0045] The content of the first curable resin in the first thermosetting resin composition and the content of the second curable resin in the second thermosetting resin composition are each preferably 30% by mass or more and 80% by mass or less, more preferably 35% by mass or more and 75% by mass or less, and further preferably 40% by mass or more and 70% by mass or less. The content of the first curable resin in the first thermosetting resin composition may be the same as or different from the content of the second curable resin in the second thermosetting resin composition. In addition, the thermosetting resin composition may be diluted with a volatile component such as a solvent as described later, but in this specification, the content (mass%) of each component in the thermosetting resin composition means a value based on the solid content excluding the volatile components.

[0046] Within the scope of not impairing the effects of the present invention, the first thermosetting resin composition may contain a thermosetting resin other than the (meth)acrylic resin when using a (meth)acrylic resin as the first curable resin, and the second thermosetting resin composition may contain a thermosetting resin other than the (meth)acrylic resin when using a (meth)acrylic resin as the second curable resin. Examples of the thermosetting resin other than the (meth)acrylic resin include polycarbonate resin, polyester resin, and epoxy resin. These thermosetting resins may be used alone or in combination of two or more.

[0047] <Blocked isocyanate curing agent> It is preferable that the first thermosetting resin composition contains a blocked isocyanate curing agent (hereinafter, sometimes referred to as a first blocked isocyanate curing agent), and the second thermosetting resin composition contains a blocked isocyanate curing agent (hereinafter, sometimes referred to as a second blocked isocyanate curing agent).

[0048] A blocked isocyanate curing agent 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 a functional group (typically a hydroxyl group) in the curable resin. The blocked isocyanate curing agent 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 malonic acid esters. The first and second blocked isocyanate curing agents may each be used alone or in combination of two or more. The first blocked isocyanate curing agent and the second blocked isocyanate curing agent may be the same or different.

[0049] The thermal dissociation temperature of the blocked isocyanate curing agent is preferably 180°C or lower. The thermal dissociation temperature is the temperature at which the blocked isocyanate curing agent dissociates to generate an isocyanate group. If the thermal dissociation temperature of the blocked isocyanate curing agent is 180°C or lower, the thermosetting resin sheet can be cured at a relatively low temperature, which is preferable. From the viewpoint of curing the paint layer at a low temperature, the thermal dissociation temperature of the blocked isocyanate curing agent is more preferably 160°C or lower, and even more preferably 140°C or lower. In addition, from the viewpoint of the storage stability of the thermosetting resin sheet, the thermal dissociation temperature of the blocked isocyanate curing agent is preferably 40°C or higher, and more preferably 60°C or higher. The thermal dissociation temperatures of the first blocked isocyanate curing agent and the second blocked isocyanate curing agent are preferably within the above ranges. The thermal dissociation temperature can be measured, for example, by mixing an equivalent amount of a resin having high reactivity with isocyanate, such as a curable resin, with the blocked isocyanate curing agent, stirring at a predetermined temperature for 6 hours, and then evaluating the gel fraction.

[0050] The content of the first blocked isocyanate curing agent in the first thermosetting resin composition and the content of the second blocked isocyanate curing agent in the second thermosetting resin composition are preferably adjusted so that the ratio of the number of functional groups in the thermosetting resin to the number of isocyanate groups in the blocked isocyanate curing agent is preferably 0.4 to 1.8, more preferably 0.6 to 1.5.

[0051] The content of the first blocked isocyanate curing agent in the first thermosetting resin composition and the content of the second blocked isocyanate curing agent in the second thermosetting resin composition are not particularly limited as long as the ratio of the number of functional groups to the number of isocyanate groups is adjusted to be within the above range, and each is preferably 5% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and even more preferably 15% by mass or more and 40% by mass or less. The content of the first blocked isocyanate curing agent in the first thermosetting resin composition may be the same as or different from the content of the second blocked isocyanate curing agent in the second thermosetting resin composition.

[0052] <Plasticizer> The first thermosetting resin composition may contain a plasticizer. The second thermosetting resin composition also preferably contains a plasticizer. The plasticizer is preferably a (meth)acrylic polymer. Examples of the (meth)acrylic polymer used as a plasticizer include non-functional type (meth)acrylic polymers, (meth)acrylic polymers having a hydroxyl group, (meth)acrylic polymers having a carboxyl group, (meth)acrylic polymers having an epoxy group, and (meth)acrylic polymers having an alkoxysilyl group. These (meth)acrylic polymers may be used alone or in combination of two or more. Among these (meth)acrylic polymers, (meth)acrylic polymers having a hydroxyl group are preferred.

[0053] The weight average molecular weight of the (meth)acrylic polymer used as the plasticizer is preferably 300 or more and 8,000 or less, more preferably 500 or more and 6,000 or less, and further preferably 1,000 or more and 4,000 or less.

[0054] The glass transition temperature of the (meth)acrylic polymer used as the plasticizer is preferably 10°C or lower, more preferably from -80°C to 0°C.

[0055] The hydroxyl value of the (meth)acrylic polymer used as a plasticizer is preferably 20 mgKOH / g or more and 250 mgKOH / g or less, more preferably 50 mgKOH / g or more and 200 mgKOH / g or less, and even more preferably 80 mgKOH / g or more and 150 mgKOH / g or less.

[0056] When the first thermosetting resin composition contains a plasticizer, the content of the plasticizer in the first thermosetting resin composition is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 5 parts by mass or more and 30 parts by mass or less, and even more preferably 7 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the total content of the curable resin, the blocked isocyanate curing agent, and the plasticizer. When the second thermosetting resin composition contains a plasticizer, the content of the plasticizer in the second thermosetting resin composition is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 5 parts by mass or more and 30 parts by mass or less, and even more preferably 7 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the total content of the curable resin, the blocked isocyanate curing agent, and the plasticizer.

[0057] The plasticizer in the first thermosetting resin composition may be the same as or different from the plasticizer in the second thermosetting resin composition, and the content of the plasticizer in the first thermosetting resin composition may be the same as or different from the content of the plasticizer in the second thermosetting resin composition.

[0058] <Coloring agent> The second thermosetting resin composition contains a colorant. By containing a colorant in the second thermosetting resin composition, the colorant layer 12 is colored, and the design of the paint layer 10 can be improved. Examples of the colorant include pigments, dyes, and luster materials. Examples of the pigments include 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. Examples of the dyes include azo dyes, anthraquinone dyes, indigoid dyes, and stilbene dyes. Examples of the glittering material include compounds in which a titanium oxide layer is provided on the surface of natural mica, synthetic mica, alumina flakes, glass flakes, etc. These colorants can be used alone or in combination of two or more.

[0059] The content of the colorant in the second thermosetting resin composition, excluding the active components of the colorant, i.e., the binder resin, dispersant, and additives, varies depending on the colorant color. For example, the content of the white colorant required to impart hiding power to the second thermosetting resin composition is much larger than the content of the black colorant. For example, when the colorant is a black colorant such as carbon black, the content of the colorant is, for example, 0.5 parts by mass or more, preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, relative to 100 parts by mass of the total content of the second curable resin, the second blocked isocyanate curing agent, and the plasticizer.

[0060] <Other ingredients> The first thermosetting resin composition and the second thermosetting resin composition may each contain components other than those described above, for example, additives other than those described above. Examples of additives include surface conditioners, antifoamers, urethanization catalysts, crosslinking agents, dispersants, inorganic fillers other than pigments and luster materials, age resistors, antioxidants, and rust inhibitors.

[0061] The first thermosetting resin composition may contain a colorant in addition to the first curable resin and the first blocked isocyanate curing agent, but it may contain no colorant or may contain a colorant in an amount that does not impair transparency. The clear layer 11 is a transparent layer, and transparency means that the transmittance of light with a wavelength of 450 nm is 80% or more. On the other hand, since the second thermosetting resin composition contains a colorant, it is preferable that the colorant layer 12 is an opaque layer.

[0062] The thickness of the clear layer 11 is not particularly limited, but is, for example, from 10 μm to 100 μm, and preferably from 15 μm to 50 μm. The thickness of the colorant layer 12 is not particularly limited, but is, for example, from 10 μm to 100 μm, and preferably from 15 μm to 50 μm.

[0063] The paint layer 10 in the paint sheet 1 of the preferred embodiment has two resin layers (a clear layer 11 and a colorant layer 12). However, the number of resin layers constituting the paint layer in the paint sheet used in the painting method of the present invention is not limited to two. For example, the paint layer 10A may be composed of one resin layer as in the paint sheet 2A shown in Fig. 5. When the coating layer 10A is composed of one resin layer, it is preferable that the coating layer 10A is a colorant layer. The coating layer 10A, which is a colorant layer, may have the same configuration as the second thermosetting resin composition described above. The type and content of the colorant may be the same as those described in the second thermosetting resin composition described above.

[0064] Also, as in the coating sheet 2B shown in FIG. 6, the paint layer 10B may be composed of three resin layers (11-13). In this case, the resin layer 11 is preferably the above-mentioned clear layer, and the resin layer 12 is preferably the above-mentioned colorant layer. The resin layer 13 existing between the two resin layers 11, 12 may be made of the same material as the resin layers 11, 12, and the resin layer 13 is preferably made of a thermosetting resin composition containing, for example, a curable resin and a blocked isocyanate curing agent. In this embodiment, even if the resin layer 13 is provided between the resin layers 11, 12, the peel strength between the resin layers can be increased, and the occurrence of interfacial peeling between the resin layers can be prevented. The thermosetting resin composition constituting the resin layer 13 may contain a colorant in addition to the curable resin and the blocked isocyanate curing agent. The design of the paint layer 10B can be further improved by a combination of the resin layer 13 containing a colorant and the resin layer 13 containing a colorant. The thermosetting resin composition constituting the resin layer 13 may further contain a plasticizer. The details of each component contained in the thermosetting resin composition are as described in the first and second thermosetting resin compositions. Furthermore, although not shown, the paint layer may be composed of four or more resin layers. In this case, it is preferable that the resin layer arranged on the surface to be bonded to the coated object is the above-mentioned second resin layer, and it is also preferable that the resin layer arranged on the surface opposite to the surface to be bonded to the coated object is the above-mentioned first resin layer. Furthermore, each resin layer between the first resin layer and the second resin layer may be made of a thermosetting resin composition, and the details thereof are as described in the above-mentioned resin layer 13.

[0065] In the above explanation, it is assumed that the paint layer has a colorant layer for the purpose of improving design, but the paint layer can be given various functions and does not necessarily have to contain a colorant layer. The paint layer may be a clear layer, and for example, in the coating sheet 2A, the paint layer 10A may be made of a second thermosetting resin composition that does not contain a colorant. In addition, the paint layer can be given various functions other than protecting the adherend or improving the design. For example, the paint layer may function as a heat-shielding coating, and in that case, the paint layer may be a heat-shielding layer containing a heat-shielding material. In addition, by providing the paint layer with surface irregularities, it is possible to impart surface properties such as matte or embossed finish. Furthermore, functions such as rust prevention, mildew prevention, heat insulation, and antistatic properties can be expressed by blending components suitable for the purpose into the curable resin composition.

[0066] In the sheet attachment step, after preparing the coating sheet 2, the coating sheet 2 is attached to the surface of the object 100 to which the working liquid 1 has been applied, as shown in Fig. 3. The attachment of the coating sheet 2 to the object 100 is not particularly limited, and may be performed by hand or by using a laminating device. Note that since the working liquid 1 exists between the coating sheet 2 and the object 100 to be coated, the coating sheet 2 is not in contact with the object 100 to be coated. This allows the coating sheet 2 to be moved in a planar direction (for example, in the direction of the arrow in Fig. 3), and the position of the coating sheet 2 can be adjusted.

[0067] Next, as shown in Fig. 4, a squeegee 60 or the like is used to push out the application liquid 1 between the coating sheet 2 and the object 100. This also pushes out air bubbles and air 70 that were present between the coating sheet 2 and the object 100 together with the application liquid 1. In this way, the coating sheet 2 can be neatly attached to the object 100.

[0068] (hardening process) In the curing step, the workpiece 100 to which the coating sheet 2 is attached is heated to cure the coating sheet 2. The heating method for heating the workpiece 100 to which the coating sheet 2 is attached to harden the coating sheet 2 is not particularly limited. For example, the coating sheet 2 may be hardened by thermal convection using heated air as a medium. The coating sheet 2 may also be hardened by radiative heating using infrared rays. Furthermore, the coating sheet may be hardened by induction heating or dielectric heating using high-frequency current. When the workpiece 100 to which the coating sheet 2 is attached is heated, the application liquid 1 remaining between the coating sheet 2 and the workpiece 100 penetrates the coating sheet 10 and then volatilizes to the outside through the coating sheet 10. Therefore, when the workpiece 100 to which the coating sheet 2 is attached is heated, the application liquid 1 remaining between the coating sheet 2 and the workpiece 100 is vaporized, and the coating sheet 2 does not blister.

[0069] The heating temperature when heating the object 100 to which the coating sheet 2 is attached is preferably 100 to 180° C., more preferably 120 to 140° C. The heating time when heating the object 100 to which the coating sheet 2 is attached is preferably 10 to 2 hours, more preferably 20 to 1 hour.

[0070] (Transfer layer) As shown in Fig. 7, a coating sheet 2C used in a coating method according to one embodiment of the present invention may further include a transfer layer 20. The transfer layer may be provided not only in the laminate sheet 2C but also in any laminate sheet having any configuration.

[0071] The transfer layer 20 is a member that protects the paint layer 10 from scratches and adhesion of foreign matter. As described below, it is also a member that serves as a support when the paint layer 10 is attached to the workpiece 100, and typically serves as a support when the paint layer 10 of the paint sheet 2 is transferred to the workpiece 100. The transfer layer 20 is preferably laminated on the surface of the paint sheet 2 opposite to the surface that is attached to the workpiece 100. The transfer layer 20 is preferably formed from a resin film. Examples of resins used for the resin film include thermoplastic resins. Specific examples of resins used in the resin film include polyolefin resins such as cyclic polyolefin resins, polyethylene resins, polypropylene resins, ethylene-vinyl acetate copolymer resins, and polymethylpentene resins, polyester resins such as polybutylene terephthalate and polyethylene terephthalate, polyamide resins, polycarbonate resins, acrylic resins, fluororesins, soft vinyl chloride resins, and tetrafluoroethylene resins. Among these, polyolefin resins are preferred from the viewpoint of conformability, which will be described later, and polyester resins are preferred from the viewpoint of easily improving bending resistance. As the polyolefin resin, a polyethylene resin, a polypropylene resin, and an ethylene-vinyl acetate copolymer resin are preferable, and as the polyester resin, a polyethylene terephthalate is preferable.

[0072] 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. In addition, in the resin film constituting the release layer, the resin contained in the resin film may be used alone or in combination of two or more types. When two or more types of resins are used in combination, a multilayer film may be formed by using different types of resins in each layer. In addition, a single layer film may be formed by mixing two or more types of resins, or one or two or more layers in a multilayer film may be formed. Examples of multilayer films include multilayer films in which a layer composed of a cyclic polyolefin resin or a polyolefin resin and a layer composed of a polyester resin are laminated together, and for example, a multilayer film in which a polyester resin layer, a polyolefin resin layer, and a polyester resin layer are laminated together in this order may be used. The multilayer film may also be a multilayer film in which each layer is composed of a polyolefin resin. Specific examples of the multilayer film include a multilayer film in which a polyethylene resin, an ethylene-vinyl acetate copolymer resin, and a polyethylene resin are laminated in this order, and a multilayer film in which a polypropylene resin, an ethylene-vinyl acetate copolymer resin, and a polypropylene resin are laminated in this order.

[0073] Each layer in the transfer layer 20 may contain additives other than the resin. As the additives, known additives that are blended into resin films may be used. Specific additives include crystal nucleating agents, fluorescent whitening agents, antioxidants, stabilizers, UV absorbers, surfactants, lubricants, fillers, crosslinking agents, crosslinking accelerators, antistatic agents, flame retardants, dispersants, pigments, dyes, processing aids, and the like.

[0074] The resin film may be a stretched resin film or a non-stretched resin film, but is preferably a non-stretched resin film. Therefore, the resin film is preferably a non-stretched polyester film, and more preferably a non-stretched polyethylene terephthalate film. By using a non-stretched resin film, it becomes easier to adjust the tensile elongation at break to a desired range as described above, and it becomes easier to prevent breakage, wrinkles, etc. during vacuum molding. In addition, the non-stretched resin film may be a multilayer film, for example, a multilayer film having a polyolefin resin layer in addition to a polyester resin layer as described above.

[0075] The transfer layer 20 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 20 is release-treated, it is preferable that the release-treated surface constitutes the surface on the paint layer side. By subjecting the transfer layer 20 to release treatment, it becomes easier to peel the transfer layer 20 from the paint layer 20. However, the transfer layer 20 does not need to be release-treated as long as it can be peeled from the paint layer 20. The thickness of the transfer layer 20 is not particularly limited, but is, for example, 10 μm or more and 1000 μm or less, preferably 20 μm or more and 500 μm or less, and more preferably 30 μm or more and 300 μm or less.

[0076] When the coating sheet 2C has a transfer layer 20, the coating method of one embodiment of the present invention further includes a transfer layer removing step of removing the transfer layer 20 from the coating sheet 10 before the curing step. The method of peeling off the transfer layer 20 is not particularly limited, and it may be peeled off by a peeling device or may be peeled off manually. Furthermore, the transfer layer 20 may be peeled off at room temperature or a temperature around it (about 15 to 35°C), but may be peeled off after the clear layer 11 is cooled.

[0077] (base material) As shown in FIG. 8, the coating sheet 2D used in the coating method of one embodiment of the present invention may further include a substrate 30. The substrate 30 used in the coating sheet 2D is a member that protects the coating layer 10 from scratches and foreign matter adhesion, and is preferably peeled off from the coating layer 10 before the coating sheet 2D is attached to the object to be coated. The substrate 30 is preferably formed from a resin film. Examples of resins used in the resin film include thermoplastic resins. Specific examples of thermoplastic resins used in the substrate 30 are the same as those that can be used in the transfer layer 20, and among them, polyester resins are preferred. The substrate may be provided not only in the laminate sheet 2D but also in any laminate sheet of any configuration.

[0078] 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. In addition, in the resin film constituting the release layer, the resin contained in the resin film may be used alone or in combination of two or more types. When two or more types of resins are used in combination, a multilayer film may be formed by using different types of resins in each layer. In addition, a single layer film may be formed by mixing two or more types of resins, or one or two or more layers in a multilayer film may be formed. Each layer in the substrate 30 may contain additives in addition to the resin. Specific examples of the additives are as described in the transfer layer.

[0079] The resin film in the substrate 30 may be a stretched resin film or a non-stretched resin film, but is preferably a non-stretched resin film. Therefore, a non-stretched polyester resin film is preferable as the resin film. By using a non-stretched resin film, it becomes easier to adjust the tensile elongation at break to a desired range as described above, and it is possible to prevent breakage, wrinkles, etc. from occurring during vacuum molding.

[0080] The substrate 30 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 substrate 30 is release-treated, it is preferable that the release-treated surface constitutes the surface on the paint layer side. By releasing the substrate 30, it becomes easier to easily peel the substrate 30 from the paint layer 20. However, the substrate 30 does not need to be release-treated as long as it can be peeled from the paint layer 20.

[0081] The thickness of the substrate 30 is not particularly limited, but is, for example, 10 μm or more and 1000 μm or less, preferably 30 μm or more and 700 μm or less, and more preferably 50 μm or more and 500 μm or less.

[0082] When the coating sheet 2D includes a substrate 30, the coating method of one embodiment of the present invention further includes a substrate removing step of removing the substrate 30 from the coating sheet 10 before the attaching step.

[0083] (Manufacturing method of coated sheet) A method for producing a coated sheet used in a coating method according to one embodiment of the present invention includes the following steps A, B, and C. (1) Process A In step A, a first coating material containing a first thermosetting resin composition containing a first curable resin and a first blocked isocyanate curing agent is applied to the transfer layer and dried to prepare a first laminate having a transfer layer and a clear layer made of the first thermosetting resin composition provided on the transfer layer. Note that the first thermosetting resin composition, the transfer layer, and the clear layer are described in the above-mentioned "coating sheet" section, so the description of the first thermosetting resin composition, the transfer layer, and the clear layer is omitted.

[0084] The first coating material may be made of the first thermosetting resin composition, but from the viewpoint of improving workability such as coating property, it is preferable that the first thermosetting resin composition is diluted with a solvent. Examples of the solvent include ethyl acetate, butyl acetate, toluene, etc.

[0085] Furthermore, the drying carried out after applying the first coating material to the transfer layer is preferably drying that includes at least the main drying step described below, and more preferably drying that includes the pre-drying step and the main drying step described below in that order.

[0086] The drying temperature in the pre-drying step is preferably 50° C. or more and 70° C. or less, and more preferably 55° C. or more and 65° C. or less. The drying time in the pre-drying step is preferably 1 minute or more and 30 minutes or less, and more preferably 2 minutes or more and 15 minutes or less. 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, and the solvent is prevented from evaporating and causing bubbles when the resin layer is cured. In addition, by setting the drying temperature to the upper limit or lower, the thermosetting resin composition can be prevented from being cured more than necessary during drying. The drying time in this drying step is preferably 1 minute or more and 30 minutes or less, more preferably 2 minutes or more and 15 minutes or less. By setting the drying time to the above lower limit or more, the solvent is easily removed appropriately, and the solvent is prevented from evaporating and generating bubbles when the resin layer is cured. In addition, by setting the drying time to the above upper limit or less, the thermosetting resin composition can be prevented from being cured more than necessary during drying.

[0087] In addition, the resin layer after drying may be subjected to initial curing as necessary. Initial curing refers to curing the thermosetting resin composition constituting the resin layer to a semi-cured state. Initial curing can be performed by heating, and is preferably performed under conditions of a heating temperature of 90°C or higher and 150°C or lower, and a heating time of about 2 minutes or higher and 5 minutes or lower.

[0088] (2) Process B In step B, a second coating material containing a second thermosetting resin composition containing a second curable resin, a second blocked isocyanate curing agent, and a colorant is applied to a substrate and dried to produce a second laminate having a substrate and a colorant layer formed on the substrate and made of the second thermosetting resin composition. Note that the second thermosetting resin composition, substrate, and colorant layer are described in the above-mentioned "coated sheet" section, so the description of the second thermosetting resin composition, substrate, and colorant layer is omitted.

[0089] The second coating material may be made of the second thermosetting resin composition, but from the viewpoint of improving workability such as coating property, it is preferable that the second thermosetting resin composition is diluted with a solvent. Examples of the solvent include ethyl acetate, butyl acetate, toluene, etc.

[0090] Moreover, the drying carried out after applying the second coating material to the substrate is preferably drying that includes at least a main drying step described below, similar to the drying carried out after applying the first coating material to the transfer layer, and more preferably drying that includes a pre-drying step and a main drying step described below in this order. Note that the pre-drying step and the main drying step have been explained in the section "Step A", so explanations of the pre-drying step and the main drying step will be omitted.

[0091] (3) Process C In step C, the first laminate and the second laminate are bonded together so that the clear layer and the colorant layer face each other. As a result, a coating sheet having a laminated structure of transfer layer / clear layer / colorant layer / substrate can be produced. In this way, by producing a coating sheet by bonding the first laminate and the second laminate together, it is possible to prevent the clear layer and the colorant layer from becoming miscible with each other, and a good two-layer structure consisting of the clear layer and the colorant layer can be obtained. Furthermore, by peeling off the transfer layer and the substrate from this coating sheet, a coating sheet consisting of the clear layer and the colorant layer can be produced.

[0092] In addition, as described above, when another resin layer is provided between the clear layer and the colorant layer, the other resin layer is first formed on a separately provided release film or the like to prepare a third laminate. Then, the third laminate is laminated to the first laminate to form another resin layer on the clear layer of the first laminate, or the third laminate is laminated to the second laminate to form another resin layer on the colorant layer of the second laminate. Thereafter, as in the above-mentioned step C, the first laminate and the second laminate are laminated together to produce a coated sheet having a clear layer, a colorant layer, and another resin layer provided between the clear layer and the colorant layer. At that time, the release film may be peeled off after or before the other resin layer is laminated on the second resin layer or the first resin layer. As the release film, a release polyethylene terephthalate film (release PET film) or the like may be used.

[0093] It is to be noted that the coated sheet used in the coating method of one embodiment of the present invention can be produced by a method other than the above-described method for producing the coated sheet.

[0094] The object to be coated by the coating method of one embodiment of the present invention is not particularly limited, and examples thereof include electrical appliances, components, vehicles such as automobiles and transport equipment, and vehicle parts used in vehicles such as automobiles and transport equipment. Examples of components include vehicle interior materials such as automobile vehicle interior materials and transport equipment vehicle interior materials, vehicle exterior materials such as automobile vehicle exterior materials and transport equipment vehicle exterior materials, exterior materials for miscellaneous goods, heavy machinery, ships, aircraft, etc., exterior walls or roof materials for houses and buildings, bridges, steel frames, plants, wind power generation blades, etc. Among these, vehicles, vehicle parts, and components are preferred, components are more preferred, and vehicle exterior materials are even more preferred. Examples of vehicle exterior materials include hoods, roofs, door panels, bumpers, fuel filler panels, trunk lids, rear gates, etc. When the coating sheet used in the coating method of one embodiment of the present invention 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 being attached to the vehicle body. The material of the object to be coated is not particularly limited, and may be any of resin materials, inorganic materials such as ceramics, and metal materials such as steel, among which metal materials such as steel are preferred. Metal materials such as steel are difficult to paint at the same time as molding the adherend by insert molding, and painting with a resin sheet is difficult, but the coating method of one embodiment of the present invention makes it easy to paint such materials.

[0095] The coating method according to one embodiment of the present invention is merely an example of the coating method according to the present invention, and is not intended to limit the coating method according to the present invention.

[0096] [Set of application liquid and paint sheet] The set of the working liquid and the coated sheet of the present invention includes a coated sheet having a paint layer and a transfer layer made of a thermosetting resin composition, and a working liquid used when attaching the coated sheet to an object to be coated. The working liquid includes at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, at least one compound selected from the group consisting of glycol ethers, glycol esters, and glycerin, glycols, or a water-soluble gelling agent and water. When the working liquid includes at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, and water, the content of the compound is 0.05 to 55% by mass. When the working liquid includes at least one compound selected from the group consisting of glycol ethers, glycol esters, and glycerin, and water, the content of the compound is 0.05 to 65% by mass. When the working liquid includes glycols and water, the content of the glycols is 0.05 to 90% by mass. In addition, when the working liquid contains a water-soluble gelling agent and water, the content of the water-soluble gelling agent is 0.05 to 10% by mass. Since the coating sheet and working liquid in the set of working liquid and coating sheet of the present invention have already been explained in the above section "Coating method", explanation of the coating sheet and working liquid in the set of working liquid and coating sheet of the present invention will be omitted. By using the set of working liquid and coating sheet of the present invention, the coating method of the present invention can be easily carried out.

[0097] [Construction fluid] The working liquid of the present invention is a working liquid used when attaching a coating sheet to a substrate. The working liquid of the present invention contains at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, at least one compound selected from the group consisting of glycol ethers, glycol esters, and glycerin, glycols, or a water-soluble gelling agent and water. When the working liquid of the present invention contains at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, and water, the content of the compound is 0.05 to 55% by mass. When the working liquid of the present invention contains at least one compound selected from the group consisting of glycol ethers, glycol esters, and glycerin, and water, the content of the compound is 0.05 to 65% by mass. When the working liquid of the present invention contains glycols and water, the content of the glycols is 0.05 to 90% by mass. When the working liquid contains a water-soluble gelling agent and water, the content of the water-soluble gelling agent is 0.05 to 10% by mass. The working liquid of the present invention has already been explained in the above section on "coating method," so a detailed explanation of the working liquid of the present invention will be omitted. By using the working liquid of the present invention, the coating method of the present invention can be easily carried out.

[0098] [Vehicles, vehicle parts, materials] The vehicle, vehicle part, and member of the present invention are coated by the coating method of the present invention. EXAMPLES

[0099] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0100] The evaluation methods in the present examples are as follows. (Appearance after sintering) The appearance after baking was evaluated as follows. The application liquid described in the Examples was sprayed onto a baked painted plate, and then a painted sheet was applied to the baked painted plate with water using a squeegee. The transfer film was peeled off from the coated sheet and placed in a fan oven set at 140°C for baking. After removing from the oven, the product was evaluated according to the following criteria. : No swelling was visible to the naked eye. ◯: Almost no swelling was visible to the naked eye. △: Slight swelling was observed with the naked eye. ×: Swelling was clearly observed by visual inspection.

[0101] (Squeegee removal) The squeegee removability was evaluated as follows. The application liquid described in the Examples was sprayed onto a baked painted plate, and then a painted sheet was applied to the baked plate with water using a squeegee. The squeegee removability was evaluated as follows. ◎: No visible water residue, and the film is completely attached to the painted board. 〇: Almost no visible water residue was observed, and the film was generally in close contact with the painted plate. △: Visible water residue was observed, but the coated plate and film were in close contact. ×: The film did not adhere to the coated plate.

[0102] (Paint layer dissolves when applied) The dissolution of the paint layer upon application was evaluated as follows. The application liquid described in the Examples was sprayed onto a baked painted plate, and then a painted sheet was applied to the baked painted plate with water using a squeegee. The condition of the coating layer at the time of application was evaluated as follows. ⊚: No dissolution of the paint layer was observed. ◯: Some dissolution of the paint layer was observed, but no problems were observed with application. ×: The paint layer was dissolved and could not be applied.

[0103] The components of the film for transfer layer, the film for substrate, and the resin layer used in the examples and comparative examples are as follows. <Transfer layer film> Unstretched cyclic polyolefin film (Toray "Decofit Q17CK", thickness 100 μm), tensile breaking elongation at 100°C (MD = 1850%, TD = 1850%)

[0104] <Film for base layer> Unstretched polyethylene terephthalate film (A-PET) ("A-PET" manufactured by Nakamoto Pax Co., Ltd., thickness 200 μm), tensile elongation at break at 100°C (MD = 1200%, TD = 980%)

[0105] <Polyol resin> Acrylic polyol resin (1): weight average molecular weight 220,000, hydroxyl value 140 mgKOH / g, solid content concentration (NV) = 30 mass% (solvent: ethyl acetate) Acrylic polyol resin (2): weight average molecular weight 340,000, hydroxyl value 75 mgKOH / g, solid content concentration (NV) = 30 mass% (solvent: ethyl acetate)

[0106] <Plasticizer> (Meth)acrylic polymer with hydroxyl groups, weight average molecular weight 2500, Toagosei Co., Ltd. "ARUFON UH-2041", hydroxyl value 120 mg KOH / mg, solid content (NV) = 100% by mass, glass transition temperature -50°C

[0107] <Pigments (colorants)> "NSP-UP 841B" manufactured by Nikko Vicks Co., Ltd., effective pigment concentration = 9% by mass, solid content concentration (NV) = 24% by mass <Brilliant materials (colorants)> "Xirallic T60-10 WNT Crystal Silver" manufactured by Merck, solid content concentration (NV) = 100% by mass

[0108] <Blocked isocyanate curing agent> Mitsui Chemicals, Inc., "Takenate B-882N", hexamethylene diisocyanate-based blocked isocyanate curing agent (HDI-based), blocking agent type: 3,5-dimethylpyrazole (DMP), solid content concentration (NV) = 70%, solvent is ethyl acetate, thermal dissociation temperature = 120°C

[0109] [Preparation of thermosetting resin compositions A and B] Each component was added in the proportions shown in Table 1, and ethyl acetate was added as a solvent to prepare coating materials of thermosetting resin compositions A and B with a solid content of 30 mass %.

[0110] [Preparation of painted sheet] Thermosetting resin composition A was applied onto the surface of the film for the transfer layer using an applicator, and then a pre-drying process was carried out under conditions of a drying temperature of 60°C and a drying time of 30 minutes, followed by a main drying process under conditions of a drying temperature of 90°C and a drying time of 30 minutes, thereby forming a 30 μm-thick clear layer on the transfer layer. Next, the thermosetting resin composition B was applied onto the surface of the substrate film using an applicator, and then a pre-drying process was carried out under conditions of a drying temperature of 60°C and a drying time of 30 minutes. After that, a main drying process was carried out under conditions of a drying temperature of 90°C and a drying time of 30 minutes, thereby forming a colorant layer having a thickness of 30 μm on the substrate. The clear layer on the transfer layer and the colorant layer on the substrate were attached together and laminated at 25° C. to obtain a laminate in which the transfer layer, the clear layer, the colorant layer, and the substrate were laminated in this order. The above evaluations were performed using the obtained laminate. The evaluation results are shown in Table 2.

[0111] [Preparation of working liquids of Examples 1 to 40 and Comparative Examples 1 to 6] The components were added and mixed in the proportions shown in Tables 2 to 6 to prepare working solutions for Examples 1 to 40 and Comparative Examples 1 to 6. The evaluation results are shown in Tables 2 to 6. The following surfactants were used in Examples 29, 31 to 40 and Comparative Examples 1 and 6. <Surfactant> "Real Perfect" manufactured by Lintec Corporation, polyoxyalkyl ether

[0112] [Table 1] *Table 1 shows the amount of each component in thermosetting resin compositions A and B based on the solid content, with the total solid content of the acrylic polyol resin, plasticizer, and blocked isocyanate curing agent being 100 parts by mass. *The amount of active pigment ingredient is the value in Table 1 multiplied by 9 / 24.

[0113] [Table 2]

[0114] [Table 3]

[0115] [Table 4]

[0116] [Table 5]

[0117] [Table 6]

[0118] Since the working liquids of Examples 1 to 40 satisfied the requirements of the working liquid of the present invention, it was found that the occurrence of blistering when the coating sheet was attached to the substrate using the working liquid and then heated could be suppressed, and the dissolution of the coating layer of the coating sheet by the working liquid could be suppressed. On the other hand, the working liquid of Comparative Example 1 did not contain the compound contained in the coating liquid of the present invention, so when the coating sheet was attached to the substrate using the working liquid and then heated, blistering occurred. Since the working liquid of Comparative Example 2 had an alcohol content of more than 55% by mass, dissolution of the coating layer of the coating sheet by the working liquid occurred. Since the working liquid of Comparative Example 3 had a glycol content of more than 90% by mass, blistering occurred when the coating sheet was attached to the substrate using the working liquid and then heated. Since the working liquid of Comparative Example 4 had a glycerin content of more than 65% by mass, blistering occurred when the coating sheet was attached to the substrate using the working liquid and then heated. The application liquid of Comparative Example 5 contained more than 65% by mass of glycol ethers, and therefore the coating layer of the coated sheet was dissolved by the application liquid. The application liquid of Comparative Example 6 was highly viscous and could not be scraped off with a squeegee. [Explanation of symbols]

[0119] 1 Construction fluid 2,2A~2D Painted Sheet 10,10A,10B paint layer 11 Clear layer 12 Colorant layer 50 Spray 60 Squeegee 70 Bubbles, Air 100 Object to be painted

Claims

1. A coating method for applying a coating to an object to be coated, comprising the steps of: a liquid application step of applying a liquid to the substrate, the liquid containing water and at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, the compound content of which is 0.05 to 55 mass %; a sheet application step of applying a coating sheet having a coating layer made of a thermosetting resin composition to the surface of the object to be coated on which the application liquid has been applied; and a curing step of heating the object to which the coating sheet is attached to cure the coating sheet.

2. A coating method for applying a coating to an object to be coated, comprising the steps of: a liquid application step of applying to the substrate a liquid containing water and at least one compound selected from the group consisting of glycol ethers, glycol esters and glycerin, the compound content of which is 0.05 to 65 mass %; a sheet application step of applying a coating sheet having a coating layer made of a thermosetting resin composition to the surface of the object to be coated on which the application liquid has been applied; and a curing step of heating the object to which the coating sheet is attached to cure the coating sheet.

3. A coating method for applying a coating to an object to be coated, comprising the steps of: a liquid application step of applying a liquid containing glycols and water, the glycols being present in an amount of 0.05 to 90% by mass, to the object to be coated; a sheet application step of applying a coating sheet having a coating layer made of a thermosetting resin composition to the surface of the object to be coated on which the application liquid has been applied; and a curing step of heating the object to which the coating sheet is attached to cure the coating sheet.

4. A coating method for applying a coating to an object to be coated, comprising the steps of: a liquid application step of applying an application liquid to the object to be coated, the application liquid including a water-soluble gelling agent and water, the water-soluble gelling agent content being 0.05 to 10 mass %; a sheet application step of applying a coating sheet having a coating layer made of a thermosetting resin composition to the surface of the object to be coated on which the application liquid has been applied; and a curing step of heating the object to which the coating sheet is attached to cure the coating sheet.

5. 5. The coating method according to claim 4, wherein the water-soluble gelling agent is at least one compound selected from the group consisting of sodium polyacrylate, sodium carboxymethylcellulose and sodium alginate.

6. The coating method according to any one of claims 1 to 5, wherein the thermosetting resin composition comprises a (meth)acrylic resin and a blocked isocyanate curing agent.

7. The (meth)acrylic resin has a weight average molecular weight of 50,000 or more and 1,000,000 or less, 7. The coating method according to claim 6, wherein the (meth)acrylic resin contains a (meth)acrylic resin having a plurality of functional groups.

8. The coating method according to claim 6, wherein the (meth)acrylic resin is a (meth)acrylic polyol.

9. The coating method according to any one of claims 1 to 5, wherein the paint layer comprises a clear layer and a colorant layer.

10. The coating sheet further comprises a transfer layer, The coating method according to any one of claims 1 to 5, further comprising a transfer layer removing step of removing the transfer layer from the coating sheet before the curing step.

11. A coated sheet having a paint layer and a transfer layer made of a thermosetting resin composition; and an application liquid used when attaching the coating sheet to an object to be coated, The working liquid contains water and at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, A set of an application liquid and a coating sheet, wherein the content of the compound in the application liquid is 0.05 to 55 mass %.

12. A coated sheet having a paint layer and a transfer layer made of a thermosetting resin composition; and an application liquid used when attaching the coating sheet to an object to be coated, The working liquid contains water and at least one compound selected from the group consisting of glycol ethers, glycol esters, and glycerin, A set of an application liquid and a coating sheet, wherein the content of the compound in the application liquid is 0.05 to 65 mass %.

13. A coated sheet having a paint layer and a transfer layer made of a thermosetting resin composition; and an application liquid used when attaching the coating sheet to an object to be coated, The working liquid contains glycols and water, A set of an application liquid and a coating sheet, wherein the content of the glycols in the application liquid is 0.05 to 90 mass %.

14. A coated sheet having a paint layer and a transfer layer made of a thermosetting resin composition; and an application liquid used when attaching the coating sheet to an object to be coated, The application liquid contains a water-soluble gelling agent and water, A set of an application liquid and a coating sheet, wherein the content of the water-soluble gelling agent in the application liquid is 0.05 to 10 mass %.

15. 15. The set of coating liquid and coated sheet according to claim 14, wherein the water-soluble gelling agent is at least one compound selected from the group consisting of sodium polyacrylate, sodium carboxymethylcellulose, and sodium alginate.

16. A coating liquid used when attaching a coating sheet to an object to be coated, The composition contains at least one compound selected from the group consisting of alcohols, ketones, cyclic ethers, and cyclic esters, and water; The content of the compound in the working liquid is 0.05 to 55 mass %.

17. A coating liquid used when attaching a coating sheet to an object to be coated, The composition comprises water and at least one compound selected from the group consisting of glycol ethers, glycol esters, and glycerin, The content of the compound in the working liquid is 0.05 to 65 mass %.

18. A coating liquid used when attaching a coating sheet to an object to be coated, Contains glycols and water, The working liquid has a content of the glycols of 0.05 to 90% by mass.

19. A coating liquid used when attaching a coating sheet to an object to be coated, Contains a water-soluble gelling agent and water, The working liquid has a content of the water-soluble gelling agent of 0.05 to 10 mass %.

20. 20. The working liquid according to claim 19, wherein the water-soluble gelling agent is at least one compound selected from the group consisting of sodium polyacrylate, sodium carboxymethylcellulose, and sodium alginate.

21. A vehicle coated by the coating method according to any one of claims 1 to 5.

22. A vehicle part coated by the coating method according to any one of claims 1 to 5.

23. A member coated by the coating method according to any one of claims 1 to 5.

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