Transfer-type curable resin sheet for painting and method for forming a paint

Abstract

A transfer-type curable resin sheet for painting, having a paint layer containing a curable resin composition capable of being cured by heat, moisture or active energy rays, and a transfer layer containing a thermoplastic resin, the face of the paint layer opposite the face provided with the transfer layer having a tack value of 300 N / cm at 23°C 2 above and 4000 N / cm 2 below.

Description

[0001] This application is a divisional application of the application with application number 202380064869.X, entitled "Transfer-type Curable Resin Sheet for Coating and Method for Forming Coating", filed on September 12, 2023. Technical Field

[0002] This invention relates to a transfer-curable resin sheet for coating and a method for forming a coating using the transfer-curable resin sheet for coating. Background Technology

[0003] Traditionally, coatings have been applied to various products such as furniture, steel sheets, and vehicle bodies to impart design, durability, weather resistance, and scratch resistance. In industrial applications of coating three-dimensional products, air or electrostatic spraying is typically used. However, considering the losses during spraying, CO2 emissions from factories, and the large-scale equipment investment involved, there is ongoing research into replacing spray coating with resin film-based finishing techniques.

[0004] Decorative technology refers to the technique of applying a resin film (decorative film) printed with text and patterns using white, black, or colored inks to the surface of various products, such as household electrical products, automotive interior decorations, and miscellaneous goods, thereby achieving high functionality and design appeal. For example, Patent Document 1 proposes a coating film as a decorative film, which has a protective layer formed on a film substrate using an active energy ray curable composition. Patent Document 1 describes how, because the protective layer is formed using an active energy ray curable composition with a specific composition, the coated surface exhibits good chemical resistance and scratch resistance.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 5394995 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In the coating film disclosed in Patent Document 1, the substrate film itself has no adhesive properties. Therefore, in order to attach it to various articles, an adhesive layer formed by an adhesive is usually formed on the side opposite to the protective layer. However, if an adhesive is used for attachment, it is prone to peeling off over time, making it unsuitable for outdoor applications requiring durability and weather resistance.

[0010] Furthermore, if a coating film as disclosed in Patent Document 1 is used, insert molding can be performed by decorating the surface with the coating film while the plastic raw material supplied by the injection mold is being molded, thereby forming a surface layer equivalent to the coating on the surface of the plastic molded article. However, this method is based on injection molding, and therefore it is difficult to apply to materials other than plastic materials, such as steel plates.

[0011] For application to materials such as steel plates, vacuum forming can also be considered for attachment. However, in vacuum forming, if the film itself does not have adhesive properties, it cannot be properly attached to the surface of various products. On the other hand, if adhesive properties are imparted to the film itself, the film becomes soft and brittle to scratches.

[0012] Therefore, the objective of this invention is to provide a transfer-curable resin sheet for coating that can be properly bonded to various articles by vacuum forming or the like, and has excellent scratch resistance.

[0013] Methods for solving problems

[0014] The inventors of this application discovered through in-depth research that by forming the resin sheet into a transfer-type multilayer structure having a coating layer and a transfer layer comprising a curable resin composition, and by making the adhesion value of the coating layer on the adhesion side within a certain range at 23°C, the above-mentioned problem can be solved, thereby completing the following invention. That is, the present invention provides the following [1] to [7].

[0015] [1] A transfer-curable resin sheet for coating, comprising a coating layer and a transfer layer, wherein the coating layer comprises a curable resin composition capable of being cured by heat, moisture or active energy rays, and the transfer layer comprises a thermoplastic resin, and the viscosity of the side of the coating layer opposite to the side on which the transfer layer is disposed is 300 N / cm at 23°C. 2 Above and 4000 N / cm 2 the following.

[0016] [2] According to the coating transfer curable resin sheet described in [1], the MD and TD tensile elongation at break of the transfer layer at 120°C are both above 500%.

[0017] [3] According to the coating transfer curable resin sheet described in [1] or [2], the MD and TD tensile elongation at break of the transfer layer at 100°C are both 500% or more.

[0018] [4] According to the coating transfer type curable resin sheet described in [1] to [3], the curable resin composition comprises a (meth)acrylic resin (A) having a weight average molecular weight of 100,000 or more and 1,000,000 or less, being in solid form, and having a plurality of functional groups.

[0019] [5] According to the coating transfer curable resin sheet of [4], the (meth)acrylic resin (A) is a (meth)acrylic polyol (A1), and the curable resin composition contains a blocked isocyanate (B).

[0020] [6] According to the coating transfer curable resin sheet of [4], the (meth)acrylic resin (A) is a polymer (A2) having (meth)acryloyl groups, and the curable resin composition contains a free radical polymerization initiator (C) that generates free radicals by heat or active energy rays.

[0021] [7] A method for forming a coating, wherein a coating transfer-type curable resin sheet as described in any one of [1] to [6] is attached to a body to be coated, and then the coating is formed by curing the coating layer.

[0022] [8] According to the coating formation method described in [7], the transfer layer is peeled off from the coating layer, thereby removing the transfer layer from the coated body.

[0023] Invention Effects

[0024] According to the present invention, a transfer-type curable resin sheet for coating can be provided, which can properly adhere the coating layer to various articles by vacuum forming or the like, and has excellent scratch resistance. Attached Figure Description

[0025] [ Figure 1 This is a schematic cross-sectional view showing an example of a transfer-curable resin sheet for coating.

[0026] [ Figure 2 This is a schematic cross-sectional view showing an example of a transfer-curable resin sheet for coating.

[0027] [ Figure 3 This is a schematic cross-sectional view showing an example of a transfer-curable resin sheet for coating.

[0028] [ Figure 4 This is a schematic cross-sectional view illustrating an example of a method for forming a coating on a coated object.

[0029] [ Figure 5 This is a schematic diagram of the apparatus for TOM molding.

[0030] [ Figure 6 This is a schematic cross-sectional view illustrating an example of a method for forming a coating on a coated object. Detailed Implementation

[0031] The present invention will now be described in more detail using embodiments.

[0032] The coating transfer-type curable resin sheet of the present invention (hereinafter, sometimes simply referred to as "transfer-type resin sheet") is a multilayer sheet having a coating layer and a transfer layer. In the transfer-type resin sheet, the coating layer is formed on one side of the transfer layer, and they are integrated. The coating layer contains a curable resin composition capable of being cured by heat, moisture, or active energy rays. The transfer layer contains a thermoplastic resin.

[0033] A transfer resin sheet is attached to various articles (hereinafter also referred to as the object to be coated) in such a way that the coating layer is in contact with the object to be coated. The coating layer is then cured, forming a cured coating layer on the surface of the object to be coated, thus forming a coating. The transfer layer can be peeled off from the object to be coated, for example, after the coating layer has cured.

[0034] The following is a detailed description of the coating layer and transfer layer used for transfer resin sheets.

[0035] <Coating Layer>

[0036] The tack value (hereinafter also simply referred to as "tack value") of the side of the coating layer constituting the transfer resin sheet of the present invention opposite to the side where the transfer layer described later is provided is 300 N / cm at 23°C. 2 Above and 4000 N / cm 2 The following applies: If the viscosity value is below the lower limit, it will not exhibit good adhesion to the adhered material. Conversely, if the viscosity value exceeds the upper limit, the hardness of the cured coating will not be sufficiently increased, and excellent scratch resistance will not be imparted.

[0037] Considering the above points, the preferred viscosity value is 500 N / cm. 2 Above and 3000 N / cm 2 Below, 700 N / cm is more preferred. 2 Above and 2500 N / cm 2 the following.

[0038] A coating layer is a layer used for, for example, protection or aesthetics of the adhered object, or to impart unique functions beyond these. The coating layer can be a coloring layer, as described later, or it can be a transparent layer. Furthermore, a unique function of the coating layer can be, for example, as a heat-insulating coating. In this case, the coating formed by the coating layer can function as a heat-insulating coating; the thermosetting resin composition can contain heat-insulating materials to make the coating layer a heat-insulating layer. Additionally, surface textures can be provided on the coating layer, thereby imparting surface properties such as matte or embossed finishes. Furthermore, functions such as rust prevention, mildew prevention, heat insulation, and antistatic properties can also be achieved by incorporating desired components into the curing resin composition.

[0039] It should be noted that the side of the coating layer opposite to the side with the transfer layer becomes the attachment surface to the object being coated.

[0040] The coating layer used in this invention comprises a curable resin composition capable of being cured by heat, moisture, or active energy rays. Examples of active energy rays include ionizing radiation such as ultraviolet rays, electron beams, alpha rays, beta rays, and gamma rays; any energy type is acceptable as long as it can generate free radicals. The curable resin composition is preferably a curable resin composition capable of being cured by heat or active energy rays.

[0041] The curable resin composition may contain a resin having functional groups that can react with the resin itself or a curing agent and cure by heat, moisture, or active energy rays. Examples of resins used in the curable resin composition include curable resins, and more specifically, examples of resins that cure by heat or active energy rays include (meth)acrylic resins, polycarbonate resins, polyester resins, and epoxy resins, with (meth)acrylic resins being preferred. Furthermore, as a resin that cures by moisture, a moisture-curing resin may be used, as described later.

[0042] The following describes in detail the case where at least a (meth)acrylic resin is used as the resin in the curable resin composition.

[0043] ((Meth)acrylic resin)

[0044] Examples of (meth)acrylic resins include those having multiple functional groups. A functional group is a group capable of reacting with heat or active energy rays. Preferred functional groups include those that react with functional groups contained in the curing agent (e.g., isocyanate groups), and those with photopolymerizable unsaturated bonds; specifically, examples include hydroxyl, amino, carboxyl, (meth)acryloyl, vinyl, and glycidyl groups. A (meth)acrylic resin may have only one functional group or two or more functional groups. Among these, a (meth)acrylic resin preferably has at least one of hydroxyl or (meth)acryloyl groups.

[0045] Therefore, (meth)acrylic resins are preferably (meth)acrylic polyols having multiple hydroxyl groups or polymers having multiple (meth)acryloyl groups.

[0046] (Meth)acrylate resins are preferably acrylic polymers obtained by polymerizing a monomer mixture containing (meth)acrylate monomers and functionalized monomers having functional groups such as hydroxyl, amino, and carboxyl groups. Such acrylic polymers can incorporate functional groups by utilizing functionalized monomers. Furthermore, the monomer mixture may also contain monomers other than (meth)acrylate monomers and functionalized monomers, such as styrene derivative monomers. It should be noted that "(meth)propylene-" refers to methpropylene- or propylene-, and other similar terms are used interchangeably.

[0047] As the above-mentioned (meth)acrylate monomers, examples of (meth)acrylate monomers that do not have the above-mentioned functional groups can be given, such as alkyl (meth)acrylates with an alkyl group having 1 or more and about 18 carbon atoms, benzyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, and 2-ethoxyethyl (meth)acrylate.

[0048] Examples of functionalized monomers include hydroxyl-containing monomers, amino-containing monomers, and carboxyl-containing monomers. One type may be used alone, or two or more may be used in combination. Among these, hydroxyl-containing monomers are preferred. Furthermore, the aforementioned (meth)acrylate polyols can be obtained by polymerizing a mixture of monomers containing (meth)acrylate monomers and hydroxyl-containing monomers.

[0049] The hydroxyl-containing monomers mentioned above are not particularly limited, and examples include (meth)acrylate monomers having hydroxyl groups, such as 2-hydroxyethyl (meth)acrylate. The amino-containing monomers are not particularly limited, and examples include (meth)acrylate monomers having amino groups, such as 2-aminoethyl (meth)acrylate. The carboxyl-containing monomers are not particularly limited, and examples include (meth)acrylic acid.

[0050] There are no particular limitations on the monomers that are styrene derivatives, but examples include styrene, α-methylstyrene, α-ethylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-ethoxystyrene, p-chlorostyrene, m-chlorostyrene, and o-chlorostyrene.

[0051] Alternatively, copolymers obtained by block or graft polymerization of the aforementioned acrylic polymer with other monomers or polymers can also be used as (meth)acrylic resins. In this case, examples of other monomers or polymers include acrylic, styrene, maleic acid, imide, silicone, and fluorine monomers, or polymers of these monomers.

[0052] Alternatively, the functional group of an acrylic polymer obtained by polymerizing a monomer mixture containing a (meth)acrylate monomer and a functionalized monomer can be reacted with a (meth)acryloyl-containing compound having a reactive group capable of reacting with the functional group and a (meth)acryloyl group, thereby making the acrylic polymer contain a (meth)acryloyl group.

[0053] As a polymer having (meth)acryloyl groups, it is preferable that the main chain of the acrylic polymer described above has an acrylic backbone having structural units derived from (meth)acrylates. However, the main chain does not necessarily need to have an acrylic backbone; it is sufficient to have (meth)acryloyl groups. The main chain may also not have an acrylic backbone; for example, it may have a urethane backbone.

[0054] In the curable resin composition, the aforementioned (meth)acrylic resin preferably comprises a (meth)acrylic resin (hereinafter referred to as (meth)acrylic resin (A)) having a weight-average molecular weight (Mw) of 100,000 or more and 1,000,000 or less, being in solid form, and having multiple functional groups. By ensuring that the weight-average molecular weight of (meth)acrylic resin (A) is within the aforementioned range and that it is in solid form, the coating layer can be easily maintained in a certain shape even before curing, and the coating layer can be appropriately formed on the transfer layer. In addition, it is easy to impart tackiness and elongation to the coating layer. Because the coating layer has tackiness and elongation, it is easy to adhere it tightly to the coated body in a manner that does not cause cracking by vacuum forming or the like, resulting in good vacuum forming properties. Furthermore, if the weight-average molecular weight is within the aforementioned range, it is easy to increase the hardness of the cured coating layer.

[0055] Based on the above considerations, the weight-average molecular weight of (meth)acrylic resin (A) is preferably 150,000 or more and 500,000 or less, more preferably 180,000 or more and 450,000 or less.

[0056] It should be noted that the weight-average molecular weight in this specification is determined using gel permeation chromatography (GPC) and can be used as a conversion value for standard polystyrene. Furthermore, "solid" refers to being solid at room temperature (23°C) and normal pressure (1 atmosphere). Similarly, "liquid" refers to being liquid at room temperature (23°C) and normal pressure (1 atmosphere).

[0057] Furthermore, the glass transition temperature (Tg) of the (meth)acrylic resin (A) is preferably below 90°C, more preferably below 80°C, even more preferably below 60°C, and preferably above 0°C, more preferably above 10°C. If the glass transition temperature of the (meth)acrylic resin (A) is within the above range, it is easy to impart certain viscosity and elongation to the coating layer.

[0058] It should be noted that, in this specification, the glass transition temperature is a value determined by differential scanning calorimetry (DSC) in accordance with JIS K 7121.

[0059] The aforementioned high molecular weight (meth)acrylic resin (A) is preferably at least one of a (meth)acrylic polyol having multiple hydroxyl groups (hereinafter also referred to as (meth)acrylic polyol (A1)) or a polymer having (meth)acryloyl groups (hereinafter also referred to as polymer (A2)).

[0060] (Meth)acrylic polyols (A1) can be obtained, for example, by polymerizing a monomer mixture containing (meth)acrylate monomers and hydroxyl-containing monomers, as described above.

[0061] The hydroxyl value of the (meth)acrylic polyol (A1) is preferably 20 mg KOH / g or more and 200 mg KOH / g or less, more preferably 30 mg KOH / g or more and 150 mg KOH / g or less. By keeping the hydroxyl value within the above range, the curing properties are improved, and the coating layer easily achieves high hardness after curing. It should be noted that the hydroxyl value can be determined according to JIS K1557-1:2007.

[0062] Polymer (A2) preferably contains (meth)acryloyl groups in a specified proportion. Specifically, the (meth)acryloyl equivalent is preferably 100 g / mol or more and 10,000 g / mol or less, more preferably 500 g / mol or more and 8,000 g / mol or less. By keeping the (meth)acryloyl equivalent within the above range, the coating layer containing polymer (A2) can be easily cured with good curability, and the coating layer has high hardness after curing. It should be noted that the (meth)acryloyl equivalent is the value obtained by dividing the weight-average molecular weight of the polymer by the number of (meth)acryloyl groups in one polymer molecule.

[0063] The content of (meth)acrylic resin (A) in the coating layer is not particularly limited, but is, for example, 18% by mass or more, preferably 19% by mass or more, and more preferably 20% by mass or more, based on the total amount of the curable resin composition. By containing a certain amount or more of (meth)acrylic resin (A), the coating properties and curing properties of the curable resin composition are easily improved.

[0064] Furthermore, the content of (meth)acrylic resin (A) in the coating layer is not particularly limited, but is, for example, 60% by mass or less, preferably 55% by mass or less, and more preferably 50% by mass or less, based on the total amount of the curable resin composition. By reducing the content of (meth)acrylic resin (A), it is easier to achieve good adhesion of the curable resin composition.

[0065] It should be noted that, in this specification, the term "based on the total amount of the curable resin composition" means, in the case where the curable resin composition contains solvents or other solvents, that the total amount of components other than solvents is set to 100% by mass. That is, "based on the total amount of the curable resin composition" means based on the total amount of solid components in the curable resin composition.

[0066] (Meth)acrylic resin (A) can be used alone or in combination with two or more types.

[0067] In the curable resin composition, the resin preferably contains, in addition to (meth)acrylic resin (A), a plasticized resin (a) with a weight average molecular weight of less than 100,000.

[0068] The plasticizing resin (a) can be a resin capable of plasticizing the curable resin composition before curing, thereby adjusting the viscosity of the coating layer to a desired range. Preferably, the plasticizing resin (a) is a plasticizing resin compatible with (meth)acrylic resin (A) and, like (meth)acrylic resin (A), has functional groups that can be cured by heat or active energy rays. Examples of resins used as plasticizing resin (a) include (meth)acrylic resins, polycarbonate resins, polyester resins, epoxy resins, polyether resins, polyolefin resins, and resins derived from plants (castor oil, etc.), with (meth)acrylic resins or polycarbonate resins being preferred.

[0069] By including a plasticizing resin (a) in addition to a high molecular weight (meth)acrylic resin (A) in the curable resin composition, it is easy to achieve good balance in terms of viscosity, coatability, curing properties of the coating layer, and elongation. The weight-average molecular weight of the plasticizing resin (a) is preferably 100 or more and 30,000 or less, more preferably 300 or more and 20,000 or less.

[0070] Furthermore, it is desirable that the aforementioned plasticizing resin (a) is a liquid in its 100% solid state. The plasticizing resin (a) may or may not have a glass transition temperature. While there is no particular limitation on the glass transition temperature of the plasticizing resin (a), it is preferably below 0°C, more preferably below -20°C, and even more preferably below -40°C. Furthermore, there is no particular limitation on the lower limit of the glass transition temperature; for example, it is above -120°C, preferably above -100°C.

[0071] If the glass transition temperature of the plasticizing resin (a) is set to the above range, the tensile elongation at break of the coating layer can be easily adjusted to the desired range, and it is also easy to exhibit tackiness.

[0072] The plasticizing resin (a) is preferably at least one of a (meth)acrylic polyol or polycarbonate diol having multiple hydroxyl groups (hereinafter also referred to as polyol (a1)) or a polymer having (meth)acryloyl groups (hereinafter also referred to as polymer (a2)).

[0073] The hydroxyl value of the (meth)acrylic polyol or polycarbonate diol (polyol (a1)) is preferably 20 mg KOH / g or more and 300 mg KOH / g or less, more preferably 50 mg KOH / g or more and 250 mg KOH / g or less. By keeping the hydroxyl value within the above range, the curability is improved, and the coating layer is easily made to have high hardness after curing.

[0074] The (meth)acrylyl equivalent of the polymer (a2) having (meth)acrylyl groups is preferably 10 g / mol or more and 10,000 g / mol or less, more preferably 100 g / mol or more and 8,000 g / mol or less. By keeping the (meth)acrylyl equivalent within the above range, the curability is improved, and the coating layer is easily made to have high hardness after curing.

[0075] (Meth)acrylic polyols or polycarbonate diols (polyol (a1)) are preferably used when the high molecular weight (meth)acrylic resin (A) is a (meth)acrylic polyol (A1). By using (meth)acrylic polyols or polycarbonate diols (polyol (a1)) in combination with (meth)acrylic polyols (A1), the curable resin composition can be readily cured by heating.

[0076] Furthermore, polymer (a2) is preferably used when the high molecular weight (meth)acrylic resin (A) is a polymer (A2) having (meth)acryloyl groups. By using polymer (a2) in combination with polymer (A2), the curable resin composition can be properly cured by irradiation with active energy rays, heating, etc.

[0077] Plasticizing resin (a) can be used alone or in combination with two or more types.

[0078] The ratio of the total content of plasticizing resin (a) and blocked isocyanate (B) in the coating layer to the (meth)acrylic resin (A) (hereinafter also referred to as "(a+B) / A") is, for example, 0.8 or more, preferably 0.9 or more, and more preferably 1.0 or more. By making (a+B) / A a certain value or more, that is, by including a certain amount or more of plasticizing resin (a) and blocked isocyanate (B), it is also possible to make the tack value of the curable resin composition a certain value or more, which facilitates good adhesion and other properties.

[0079] Furthermore, (a+B) / A is, for example, 5 or less, preferably 4.5 or less, and more preferably 4 or less. By making (a+B) / A a certain value or less, the hardness of the cured resin composition can be a certain value or more, thus imparting excellent scratch resistance.

[0080] It should be noted that when the curable resin composition contains solvents or other solvents, (a+B) / A is the mixing ratio described above based on the total amount of solid components. The same applies to a / A as described later.

[0081] (Blocked isocyanate (B))

[0082] The curable resin composition of the present invention may contain a curing agent that reacts with the aforementioned curable resin to cure it. The curing agent is preferably a thermosetting agent that reacts with the curable resin by heating. As a thermosetting agent, when using a (meth)acrylic polyol (A1), a blocked isocyanate (B) is preferred. That is, in one embodiment, the curable resin composition of the present invention preferably contains a (meth)acrylic polyol (A1) and a blocked isocyanate (B).

[0083] Blocked isocyanate (B) is a compound obtained by blocking isocyanate groups using a protecting group. If exposed to high temperature, the protecting group (blocked part) undergoes thermal dissociation and detaches, and a curing reaction occurs between the resulting isocyanate group and the above-mentioned (meth)acrylic polyol (A1), (meth)acrylic polyol or polycarbonate diol (polyol (a1)).

[0084] Blocked isocyanates (B) can be obtained, for example, by reacting a blocking agent with an isocyanate compound having two or more isocyanate groups in one molecule.

[0085] There are no particular limitations on the isocyanate compounds having two or more isocyanate groups in one molecule, and examples include toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, phenylene diisocyanate, hydrogenated phenylene diisocyanate, or modified forms thereof.

[0086] Examples of blocking agents include pyrazoles, phenols, oximes, lactams, and active methylene compounds.

[0087] The amount of blocked isocyanate (B) in the curable resin composition is preferably such that the ratio of the number of functional groups in the (meth)acrylic polyol (A1) to the number of isocyanate groups in the blocked isocyanate (B) (number of functional groups / number of isocyanate groups) is 0.4 or more and 2.5 or less, preferably 0.6 or more and 1.4 or less.

[0088] The content of blocked isocyanate (B) is not particularly limited, but is preferably 20% by mass or more and 50% by mass or less, more preferably 25% by mass or more and 45% by mass or less, based on the total amount of the curable resin composition.

[0089] (Free radical polymerization initiator (C))

[0090] The curable resin composition of the present invention may contain a free radical polymerization initiator (C) that generates free radicals through heat or active energy radiation. When a polymer having (meth)acryloyl groups (A2) is used in the curable resin composition, the free radical polymerization initiator (C) is preferably used. That is, in one embodiment, the curable resin composition of the present invention preferably contains a polymer having (meth)acryloyl groups (A2) and a free radical polymerization initiator (C).

[0091] Examples of thermal free radical polymerization initiators that utilize heat to generate free radicals include azo compounds and organic peroxides. Examples of azo compounds include 2,2'-azobis(2,4-dimethylpentanonitrile) and azobisisobutyronitrile. Examples of organic peroxides include benzoyl peroxide, ketone peroxide, ketal peroxide, hydroperoxide, dialkyl peroxide, peroxide ester, diacyl peroxide, and dicarbonate peroxide.

[0092] Examples of photoradical polymerization initiators that utilize active energy rays to generate free radicals include benzophenone compounds, alkyl phenyl ketone compounds, acetophenone compounds, acylphosphine oxide compounds, dicocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanone.

[0093] As a free radical polymerization initiator (C), a photoradical polymerization initiator is preferred.

[0094] The content of the free radical polymerization initiator (C) in the curable resin composition, based on the total amount of the curable resin composition, is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 7% by mass or less, and even more preferably 0.2% by mass or more and 5% by mass or less. By keeping the content of the free radical polymerization initiator (C) within these ranges, the curable resin composition can be cured with high curability by heating or irradiation by active energy rays.

[0095] When a curable resin composition is formulated to be curable by moisture, the composition may contain a moisture-curing resin. Examples of moisture-curing resins include prepolymers having isocyanate groups at the ends. Examples of prepolymers having isocyanate groups at the ends include prepolymers obtained by reacting a polyisocyanate with a compound containing active hydrogen and / or a polymer containing active hydrogen.

[0096] As a polyisocyanate used in the formulation of prepolymers with isocyanate groups at the ends, toluene diisocyanate, crude toluene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, carbodiimide diphenylmethane diisocyanate, phenyl diisocyanate, 1,5-naphthalene diisocyanate, diphenylmethylene diisocyanate, hexamethylene diisocyanate, etc. can be used, with polymethylene polyphenyl isocyanate being preferred.

[0097] As the above-mentioned compounds and polymers containing active hydrogen, substances such as the following can be used.

[0098] Polymers containing active hydrogen, such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerol, trimethylolethane, trimethylolpropane, castor oil, diglycerol, sorbitol, pentaerythritol, dipentaerythritol, etc., and polymers containing active hydrogen obtained by addition polymerization of the above-mentioned active hydrogen compounds with alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran, etc., alone or in mixtures thereof, having two or more terminal hydroxyl groups, with an average molecular weight of 3,000 or less and an average functional group number of 2 or more, preferably an average molecular weight of 200 to 1,000 and an average functional group number of 2 to 2.5, can be used. It can also be used in combination with other polyester polyols, oil-modified polyester polyols, poly-ε-caprolactone polyols, polycarbonate diols, acrylic polyols, polyamines, polyamides, urea resins, and melamine resins, which are polymers containing active hydrogen with an average molecular weight of less than 3,000 and an average functional group of more than 1.5, preferably with an average molecular weight of 200 to 1,000 and an average functional group of 2 to 2.5.

[0099] Prepolymers with terminal isocyanate groups have an effective NCO content of 1 to 15% by mass, preferably 8 to 13% by mass.

[0100] Prepolymers with terminal isocyanate groups can be synthesized as follows: the above-mentioned polyisocyanate and a conventional polyol including the above-mentioned polymer containing active hydrogen are subjected to a carbamate reaction in a system in which moisture is blocked, under conditions of excess isocyanate and at a temperature of 40°C to 90°C, preferably 55°C to 75°C.

[0101] The above-mentioned carbamate esterification reaction is usually carried out in an organic solvent. Suitable solvents include ketone solvents such as methyl ethyl ketone, ester solvents such as ethyl acetate, aromatic solvents such as toluene and xylene, and other solvents commonly used as solvents in coatings. The carbamate esterification reaction can also use a catalyst. Suitable catalysts include tertiary amine catalysts such as triethylamine and dimethylaniline, or metal catalysts such as tin and zinc. These catalysts also act as catalysts during the reaction with moisture in the air when the coating film is formed.

[0102] (Pigment (D))

[0103] The curable resin composition may contain pigment (D). By including pigment (D) in the curable resin composition, it is possible to color the coating layer to form a colored layer, or to impart a glitter effect to the coating layer. Therefore, the design flexibility of coatings formed from transfer resin sheets can be improved.

[0104] Examples of pigments (D) include aluminum pigments such as aluminum flakes, mica pigments, graphite pigments, glass flake pigments, metal oxide pigments such as titanium dioxide, iron oxide, and titanium yellow, inorganic pigments such as carbon black, clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, talc, silica, and alumina white, as well as azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, perylene pigments, violet ketone pigments, benzimidazolone pigments, reduction pigments, isoindoline pigments, isoindoline ketone pigments, metal chelate azo pigments, phthalocyanine pigments, indanone pigments, dioxane pigments, and indigo pigments, but are not limited to these.

[0105] The effective component of pigment (D) in the coating layer, i.e., the pigment component excluding binder resin, dispersant, and additives, is, based on the total amount of the curable resin composition, for example, 0.1% by mass or more and 50% by mass or less, preferably 0.5% by mass or more and 40% by mass or less, and more preferably 1% by mass or more and 30% by mass or less. By setting the content of pigment (D) to these lower limits or above, the coating formed from the transfer resin sheet can be appropriately colored, or appropriately given a glossy finish, etc. Furthermore, by setting the content of pigment (D) to the aforementioned upper limits or below, it is possible to prevent various properties of the coating layer, such as shape retention, curing properties, elongation, and tackiness, from being reduced due to the pigment (D).

[0106] The curable resin composition may contain colorants other than pigment (D), or it may contain dyes. Known dyes can be used, such as azo dyes, anthraquinone dyes, indigo dyes, and uranium dyes.

[0107] In addition, the curable resin composition may contain components other than those mentioned above, such as additives other than those mentioned above. Examples of additives include binding agents, urethane reaction catalysts, urethane reaction regulators, defoamers, surface conditioners, wax additives, crosslinking agents, dispersants, inorganic fillers other than pigments, anti-aging agents, antioxidants, ultraviolet absorbers, and rust inhibitors.

[0108] The coating layer can be a single-layer structure or a multi-layer structure. In the case of a single-layer structure, the coating layer may comprise a single layer made of the aforementioned curable resin composition. In the case of a multi-layer structure, each layer may be made of the aforementioned curable resin composition. In the case of a multi-layer structure, for example, multiple layers made of the aforementioned curable resin composition with different compositions of adjacent layers may be stacked together. In the case of a multi-layer structure, the coating layer may include at least one of, for example, a coloring layer containing either a pigment or a colorant other than a pigment, and a transparent layer not containing either a pigment or a colorant other than a pigment; however, it is preferable to include both a coloring layer and a transparent layer. When both a coloring layer and a transparent layer are included, the transparent layer and the coloring layer can be sequentially arranged from the transfer layer side. With such a layer configuration, when the transfer resin sheet is attached to the substrate, it is arranged from the substrate side in the order of the coloring layer and the transparent layer.

[0109] By providing a coloring layer as described above, the substrate can be colored using a coating formed from the paint layer. Furthermore, by providing a transparent layer in addition to the coloring layer, the coloring layer can be protected or given a glossy finish.

[0110] The transparent layer is a transparent layer, requiring only enough transparency to allow visual identification of the color of the colored layer through the transparent layer. For example, the transmittance of light at a wavelength of 450 nm can be 80% or more. The transparent layer can be a coating film without colorants, but it may also contain a small amount of colorant as long as it does not impair its function. Furthermore, in the curing resin composition used for the transparent layer, if a (meth)acrylic resin is used as the curing resin, it must contain at least a high molecular weight (meth)acrylic resin. However, in this case, it may or may not contain a plasticizing resin.

[0111] Of course, when the coating layer has a multi-layer structure, it is not limited to a two-layer structure of a transparent layer and a coloring layer. Various layered structures are possible. Two or more coloring layers and one or more transparent layers can be added to create a structure of three or more layers. Alternatively, the transparent layer can be omitted, resulting in a structure consisting of two coloring layers. Furthermore, two or more transparent layers can be added. Additionally, a heat-insulating layer or similar layer can be added between the transparent layer and the coloring layer to create a structure of three or more layers.

[0112] The thickness of the coating layer is not particularly limited, for example, it is about 5μm or more and 1000μm or less, preferably 10μm or more and 500μm or less.

[0113] Furthermore, when a coloring layer and a transparent layer are provided on the coating layer, the thickness of the coloring layer is not particularly limited, for example, it is 10 μm or more and 100 μm or less, preferably 15 μm or more and 50 μm or less. Similarly, the thickness of the transparent layer is not particularly limited, for example, it is 10 μm or more and 100 μm or less, preferably 15 μm or more and 50 μm or less.

[0114] The curable resin composition constituting the coating layer can be in an uncured or semi-cured state. An uncured or semi-cured state refers to a state where the coating layer will further cure if heated or irradiated with active energy rays. It should be noted that a semi-cured state refers to a partially cured state of the curable resin composition, while an uncured state refers to a state where the curable resin composition has not yet cured.

[0115] <Transfer Layer>

[0116] In the transfer-type resin sheet of the present invention, the transfer layer serves as a support for transferring the coating layer to the substrate, such as a vehicle body. Preferably, the MD and TD elongation at break of the transfer layer at 120°C are both 500% or more. If the MD and TD elongation at break of the transfer layer are both 500% or more, then when the transfer-type resin sheet is attached to the substrate by vacuum forming or the like, the transfer-type resin sheet easily follows the shape of the substrate, easily prevents breakage, wrinkles, etc., and easily ensures that the transfer-type resin sheet adheres appropriately to the substrate.

[0117] From the viewpoint of achieving excellent vacuum forming properties and ensuring that the transfer resin sheet adheres more appropriately to the object to be coated, it is preferable that the MD and TD tensile elongation at break of the transfer layer at 120°C are both 600% or more, and even more preferably both 700% or more.

[0118] In addition, there is no particular upper limit to the tensile elongation at break at 120°C, but the tensile elongation at break of MD and TD at 120°C can be, for example, below 3000%.

[0119] Preferably, the MD and TD tensile elongation at break of the transfer layer at 100°C are both above 500%. If the MD and TD tensile elongation at break of the transfer layer are both above 500%, then when the transfer resin sheet is attached to the object to be coated by means of vacuum forming, the transfer resin sheet can easily follow the shape of the object to be coated, easily prevent breakage, wrinkles, etc., and easily make the transfer resin sheet fit properly and tightly against the object to be coated.

[0120] From the viewpoint of achieving excellent vacuum forming properties and ensuring that the transfer resin sheet adheres more appropriately to the object to be coated, it is preferable that the MD and TD tensile elongation at break of the transfer layer at 100°C are both 600% or more, and even more preferably both 700% or more.

[0121] In addition, there is no particular upper limit to the tensile elongation at break at 100°C, but the tensile elongation at break of MD and TD at 120°C can be, for example, below 3000%.

[0122] It should be noted that the tensile elongation at break of both MD and TD in the transfer layer should be within the above-mentioned range at at least one temperature between 100°C and 120°C. For example, when the vacuum forming temperature is higher, the tensile elongation at break of MD and TD should be within the above-mentioned range at 120°C; when the vacuum forming temperature is lower, the tensile elongation at break of MD and TD should be within the above-mentioned range at 100°C.

[0123] The tensile elongation at break of the transfer layer at 100°C and 120°C is the elongation at the point of break determined in a tensile test of the film constituting the transfer layer, and can be determined according to the test method of JIS K7127.

[0124] The tensile elongation at break of the transfer layer at 100℃ and 120℃ can be appropriately adjusted by the type of resin constituting the transfer layer, the presence or absence of stretching of the resin film constituting the transfer layer, and the degree of stretching.

[0125] The transfer layer is made of thermoplastic resin. By using a thermoplastic resin as the transfer layer, the elongation at break at least at one of 100°C and 120°C is improved, and the transfer resin sheet easily follows the shape of the object being coated when it is applied to the object. Furthermore, it easily prevents breakage, wrinkles, etc., and makes it easy for the transfer resin sheet to adhere properly to the object being coated. Specifically, examples of thermoplastic resins include cyclic polyolefin resins, polyolefin resins, polyester resins, polyamide resins, acrylonitrile butadiene styrene resins, polycarbonate resins, acrylic resins, fluoropolymers, vinyl chloride resins, polymethylpentene resins, and tetrafluoroethylene resins. Using these resins easily improves the aforementioned elongation at break.

[0126] Cyclic polyolefin resins are polymers containing structural units derived from cyclic olefins. Examples of cyclic olefins include tetracyclododecene, norbornene, and cyclic conjugated dienes. Cyclic polyolefin resins can be polymers of cyclic olefins, copolymers of cyclic olefins and α-olefins, or hydrides thereof. Examples of the aforementioned α-olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene, which are chain-like α-olefins with approximately 12 to 12 carbon atoms; among these, ethylene is preferred.

[0127] Polyolefin resins are polyolefin resins other than cyclic polyolefin resins; specifically, examples include polypropylene resin and polyethylene resin. Among these, polypropylene resin is preferred.

[0128] The polypropylene resin can be homopolymer polypropylene, atactic polypropylene, or a copolymer of propylene with a small amount (e.g., less than 10% by mass) of other α-olefins. Examples of other α-olefins include ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, and 1-decene, which are chain-like α-olefins with approximately 12 or more carbon atoms.

[0129] Examples of polyethylene resins include low-density polyethylene (LDPE, density: less than 0.930 g / cm³). 3 Medium-density polyethylene (MDPE, density: 0.930 g / cm³) 3 Above and below 0.942 g / cm³ 3 High-density polyethylene (HDPE, density: 0.942 g / cm³) 3 The above), linear low-density polyethylene (LLDPE), etc.

[0130] As a polyester resin, there is no particular limitation, but polybutylene terephthalate (PBT) resin can be an example. PBT resin can be a homopolymer formed from terephthalic acid units and 1,4-butanediol units, or a copolymer containing units from other copolymer components besides terephthalic acid and 1,4-butanediol units. Other copolymer components include glycol components and dicarboxylic acid components, which can be contained in, for example, a proportion of less than 30 mol% in all units constituting the copolymer.

[0131] The resin film can be a single-layer film consisting of one layer, or a multilayer film consisting of two or more layers. Furthermore, in the resin film constituting the transfer layer, the resin contained in the resin film can be a single type or a combination of two or more types. When using two or more types of resin, different types of resin can be used in each layer to form a multilayer film. Alternatively, a single-layer film can be formed using a resin obtained by mixing two or more resins, or one or more layers of a multilayer film can be formed.

[0132] Of the resins used in the resin film, the preferred resins are one or more selected from cyclic polyolefin resins, polyolefin resins, and polyester resins.

[0133] More preferably, the resin is selected from one or more resins chosen from cyclic polyolefin resins, polypropylene resins, and PBT resins. By using these resins, the solvent resistance of the transfer layer is easily increased, and even if the curable resin composition is diluted with a solvent and directly applied to the transfer layer, deterioration of the transfer layer can be prevented. From these viewpoints, the resin used as the resin film is further preferably selected from one or more resins chosen from cyclic polyolefin resins and polypropylene resins, and even more preferably from cyclic polyolefin resins.

[0134] In the case of a multilayer film, it can be composed of the following resin layers: a resin layer (also referred to as the first layer) in which the resin is composed of at least one resin selected from cyclic polyolefin resin, polypropylene resin, and PBT resin; and a resin layer (also referred to as the second layer) in which the resin is composed of a polyolefin resin such as polyethylene resin. For example, it is also preferable to obtain a multilayer film in which the first layer, as a skin layer, is provided on one or both sides of the second layer. Specifically, it is preferable to obtain a multilayer film in which the first layer, composed of PBT resin, is provided on one or both sides of the second layer, which is composed of polyethylene resin. In this case, it is more preferable to provide the first layer (skin layer) on both sides of the second layer (core layer). It should be noted that when the first layer is provided only on one side of the second resin layer, the first layer can be disposed on the coating layer side.

[0135] Each layer in the transfer layer may contain additives in addition to resin. Known additives that are incorporated into the resin film can be used as additives. Specific examples of additives include nucleating agents, fluorescent whitening agents, antioxidants, stabilizers, ultraviolet absorbers, surfactants, lubricants, fillers, crosslinking agents, crosslinking accelerators, antistatic agents, flame retardants, dispersants, pigments, dyes, and processing aids.

[0136] Furthermore, the resin film constituting the transfer layer can be a stretched film such as a uniaxially stretched film or a biaxially stretched film, or it can be an unstretched film, but an unstretched film is preferred. Additionally, when using a stretched film, a stretched film with a low stretch ratio can be used. By using an unstretched film or a stretched film with a low stretch ratio in the resin film, it is easier to improve the elongation at break. Furthermore, the resin film can be a T-die film extruded using a T-die, or it can be a blown film.

[0137] The transfer layer can also be a layer obtained by releasing at least one surface using a release agent such as a silicone-based release agent, a non-silicone-based (organic release agent type) release agent, or a fluorinated release agent. When the transfer layer is released, the surface to be released is preferably the surface facing the coating layer. Releasing the transfer layer facilitates good peelability from the coating layer.

[0138] The thickness of the transfer layer is not particularly limited, for example, it is 30μm or more and 300μm or less, preferably 50μm or more and 200μm or less.

[0139] [Layer Composition]

[0140] For example, such as Figure 1 As shown, the transfer resin sheet 10 includes a coating layer 11 and a transfer layer 12, with the coating layer 11 formed on one side of the transfer layer 12, and they are integrally formed. The coating layer 11 can be directly laminated onto the transfer layer 12.

[0141] Transfer resin sheet 10 can be like Figure 1 As shown, it consists of a coating layer 11 and a transfer layer 12, but other layers may also be included. For example, such as Figure 2 As shown, the transfer resin sheet 10 may include a release film 13, which is attached to the surface of the coating layer 11. The release film 13 can be any known release film and is not particularly limited; it can be a release film made of resin film, or it can be obtained by treating at least one surface of the resin film with a release agent such as a silicone-based release agent, a non-silicone-based (organic release agent), or a fluorinated release agent. When the release film 13 is treated, the treated surface can be positioned in contact with the coating layer 11. The release film 13 can be peeled off from the coating layer 11 before the transfer resin sheet 10 is attached to the object to be coated, thereby removing it from the transfer resin sheet 10.

[0142] In addition, such as Figure 3 As shown, the transfer resin sheet 10 may have a support layer 14, and the support layer 14 is attached to the surface of the coating layer 11. The support layer 14 may be formed using resin, rubber, or the like. Alternatively, the support layer 14 may be a layer obtained by performing a demolding treatment on the surface in contact with the coating layer 11, similar to a release film.

[0143] (Manufacturing method of transfer resin sheet)

[0144] The method for manufacturing the transfer-type resin sheet in this invention is not particularly limited. Preferably, a coating solution is prepared by diluting a curable resin composition with a solvent, applying it onto a transfer layer composed of a resin film or the like, and then drying it. The coating solution is not particularly limited; for example, it can be obtained by mixing curable resin, curing agent, free radical polymerization initiator, pigment, and other additives in a solvent to form the curable resin composition.

[0145] Examples of solvents include ethyl acetate, butyl acetate, and toluene. From the viewpoint of ease of obtaining and workability of the desired transfer resin sheet, ethyl acetate is preferred. There is no particular limitation on the amount of solvent used; it is, for example, 50 parts by mass or more and 1000 parts by mass or less, preferably about 100 parts by mass or more and 500 parts by mass or less, relative to 100 parts by mass of the curable resin such as (meth)acrylic resin.

[0146] There are no particular limitations on the method of applying the coating liquid to the transfer layer; any known coating device can be used to apply it to the transfer layer.

[0147] The drying temperature in the pre-drying process is preferably 50°C or higher and 70°C or lower, more preferably 55°C or higher and 65°C or lower. The drying time in the pre-drying process is preferably 10 minutes or higher and 60 minutes or lower, more preferably 15 minutes or higher and 45 minutes or lower.

[0148] The drying temperature in the formal drying process is preferably 85°C or higher and 130°C or lower, more preferably 90°C or higher and 120°C or lower. If the drying temperature is above these lower limits, it is easy to properly remove the solvent from the coating liquid and prevent the solvent or the like from vaporizing and generating bubbles during the curing of the coating layer. In addition, by setting it to the upper limit or lower, it is possible to prevent the curable resin composition from curing to the necessary degree during drying.

[0149] The drying time in the formal drying process is preferably 10 minutes or more and 60 minutes or less, more preferably 15 minutes or more and 45 minutes or less. By setting the drying time to the lower limit or above, it is easier to properly remove the solvent from the coating liquid and prevent the solvent from vaporizing and generating bubbles during the curing of the coating layer. In addition, by setting it to the upper limit or below, it is possible to prevent the curable resin composition from curing to the necessary degree during drying.

[0150] In addition, initial curing can be performed on the dried transfer resin sheet as needed. Initial curing refers to curing the curable resin composition constituting the coating layer to a semi-cured state. Initial curing can be performed by heating, by irradiation with active energy rays, or by applying moisture. It should be noted that when heating is used, the heating temperature can be above 135°C and below 150°C, and the heating time can be above 5 minutes and below 10 minutes.

[0151] (How to use transfer resin sheets)

[0152] The transfer resin sheet of this invention is used to form a coating on various articles (the object to be coated). Specifically, after the transfer resin sheet is applied to various objects to be coated, the coating layer is cured, and the cured coating layer is used as the coating. It should be noted that the transfer layer can be peeled off from the coating layer attached to the object to be coated, thereby removing it from the object to be coated.

[0153] The object to be coated using transfer resin sheets is not particularly limited, and examples include, for instance, electrical products. Other examples include interior trim materials for automobiles and railway vehicles, exterior trim materials for automobiles and railway vehicles, and miscellaneous goods. Furthermore, examples include exterior trim materials for heavy machinery, ships, and aircraft; exterior wall and roof materials for residences and buildings; and materials for bridges, steel reinforcement, factory equipment, and wind turbine blades. Among these, exterior trim materials for automobiles are preferred. Examples of exterior trim materials for vehicles include, for instance, sunroofs, doors, bumpers, fuel filler panels, trunk lids, and rear folding panels. When the transfer resin sheet is applied to exterior trim materials for vehicles, it can be applied to exterior trim materials already installed on the vehicle body or to exterior trim materials installed in front of the vehicle body.

[0154] Furthermore, the material of the object to be coated is not particularly limited and can be any material among resin materials, inorganic materials such as ceramics, and metallic materials such as steel. Among these, metallic materials such as steel are preferred. Metallic materials such as steel are difficult to coat simultaneously with the forming of the object to be coated by insert molding, and are also difficult to coat with resin sheets. However, by using the transfer resin sheet of the present invention, coating can be easily performed even for such materials.

[0155] There are no particular limitations on the method of attaching the transfer resin sheet to the object to be coated. It can be done manually using a brush or similar applicator, or using a lamination device. Alternatively, it can be done by pressure molding, insert injection, vacuum forming, etc., with vacuum forming being the preferred method. When attaching by vacuum forming, the transfer resin sheet can be heated to, for example, 90°C or higher and 130°C or lower, preferably 100°C or higher and 125°C or lower, and then vacuum formed.

[0156] Transfer resin sheets can be pre-shaped to correspond to the shape of the object to be coated through methods such as vacuum forming, pressure forming, or pneumatic forming, and then attached to the object. In the case of pre-shaping, curable resin sheets are preferably as follows: Figure 3As shown, the transfer resin sheet is pre-shaped with the support layer 14 attached to the coating layer 11. The pre-shaping is performed by shaping the transfer resin sheet into a certain shape using a jig. By pre-shaping the transfer resin sheet with the support layer, the coating layer can be prevented from adhering to the jig.

[0157] Of the above, pre-forming is preferably performed by vacuum forming. Furthermore, the pre-formed transfer resin sheet can be attached to the object to be coated after the support layer is removed. In this case, the transfer resin sheet can be attached manually, using a lamination device, or by other methods.

[0158] As described above, the coating layer of the transfer resin sheet attached to the object to be coated can be cured. When the curable resin composition can be cured by heat, the coating layer can be cured by heating. The heating temperature for curing by heating is not particularly limited, as long as it is sufficient to cure the coating layer; for example, it is 135°C or higher and 170°C or lower, preferably 140°C or higher and 160°C or lower. Furthermore, the heating time is, for example, 30 minutes or higher and 90 minutes or lower, preferably 60 minutes or higher and 90 minutes or lower.

[0159] Furthermore, if the curable resin composition can be cured by active energy rays, it can be cured by irradiating the coating layer with active energy rays. From the perspectives of curability and convenience, ultraviolet (UV) light is preferred as the active energy ray. The irradiation dose of the active energy ray is not particularly limited, for example, 200 mJ / cm². 2 Above 5000mJ / cm 2 The preferred value is 500 mJ / cm. 2 Above and 2000mJ / cm 2 the following.

[0160] In addition, if the curable resin composition can be cured by moisture, it can be cured by moisture.

[0161] Regarding transfer-type resin sheets, since the transfer layer has tensile strength, its vacuum forming properties are excellent. Therefore, transfer-type resin sheets are preferably attached to the substrate by vacuum forming. Furthermore, it is also preferable to attach them to the substrate after pre-shaping via vacuum forming. Hereinafter, refer to... Figure 4 This describes in more detail a method for forming a coating on a substrate by attaching a transfer resin sheet to the substrate using vacuum forming.

[0162] First, prepare 20 bodies to be painted, such as... Figure 4As shown in (a) and (b), the transfer resin sheet 10 is attached to the substrate 20 by vacuum forming. At this time, the transfer resin sheet 10 is attached to the substrate 20 in such a way that the coating layer 11 contacts the substrate 20. Furthermore, the transfer resin sheet 10 can be stretched and shaped along the shape of the substrate 20 while being vacuum formed, thus adhering tightly to the substrate 20.

[0163] Here, vacuum forming is preferably TOM forming. TOM stands for "Three Dimension Overlay Method". If TOM forming is applied, even for a coating body 20 with a complex shape, the transfer resin sheet 10 can be tightly attached and adhered along its shape.

[0164] exist Figure 5 The diagram shows a schematic of an apparatus for TOM molding. Within the TOM molding apparatus 30, a transfer resin sheet 10 is provided. An upper chamber 31 is located above the transfer resin sheet 10, and a lower chamber 32 is located below the transfer resin sheet 10. Inside the lower chamber 32, a coating material 20 is positioned on an upper and lower lifting platform 35. The coating layer of the transfer resin sheet 10 is positioned on the lower side, and the transfer layer is positioned on the upper side.

[0165] In this state, the pressure in the upper chamber 31 and lower chamber 32 is reduced, and the transfer resin sheet 10 is heated using a near-infrared heater or the like. Next, the workpiece 20 to be coated is raised using the upper and lower lifting platforms 35, pressing the workpiece 20 against the transfer resin sheet 10. Then, compressed air is introduced only into the upper chamber 11 and held for a certain time. This allows the transfer resin sheet 10 to be adhered to the surface of the workpiece 20, thus bonding the transfer resin sheet 10 to the workpiece 20. Of course, vacuum forming can also be performed using methods other than TOM forming.

[0166] If a transfer resin sheet 10 is attached to the object to be coated 20, then the following steps are as follows: Figure 4 As shown in (c), the coating layer 11 is cured, and a coating is formed on the object to be coated 20 using the cured coating layer 11. The coating layer 11 can be cured by heating, by irradiation with active energy rays, or by moisture. Details of the heating and irradiation conditions with active energy rays are as described above.

[0167] Then, as Figure 4 As shown in (d), the transfer layer 12 can be peeled off from the coating layer 11, thereby removing the transfer layer 12 from the substrate 20. However, the transfer layer 12 can also be peeled off from the coating layer 11 before curing, thereby removing it from the substrate 20. Additionally, as... Figure 4As shown in (d), the coating layer 11 can be trimmed, that is, unnecessary parts can be appropriately cut off.

[0168] Next, refer to Figure 6 This section provides an example of a method for forming a coating using a transfer resin sheet pre-shaped via vacuum forming. In the case of pre-shaping, such as... Figure 6 As shown in (a), a transfer resin sheet 10 is prepared, for example, having a support layer 14 and the support layer 14 being attached to the surface of the coating layer 11, and a jig 40 is also prepared. The surface 40A of the jig 40 may have a shape consistent with the surface shape of the object to be coated 20. The jig 40 may be made of any material, and may be formed of resin material or metal.

[0169] The transfer resin sheet 10 having the support layer 14 can be disposed on the clamp 40 such that the side of the support layer 14 becomes the surface 40A side of the clamp 40, as... Figure 6 As shown in (b), the transfer resin sheet 10 is sealed to the fixture 40 by vacuum forming, and the transfer resin sheet 10 is elongated while being shaped to correspond to the surface shape of the object to be coated 20. The conditions for vacuum forming are as described above. In addition, vacuum forming is preferably performed by TOM forming, but it can also be performed by other methods. It should be noted that the specific method of TOM forming is as described above, and the fixture 40 can be arranged in the TOM forming apparatus 30 instead of the object to be coated 20.

[0170] like Figure 6 As shown in (b), the pre-shaped transfer resin sheet 10 can be trimmed, that is, unnecessary parts can be appropriately cut off.

[0171] In addition, next, such as Figure 6 As shown in (b) and (c), the pre-shaped transfer resin sheet 10 is removed from the fixture 40. Additionally, the support layer 14 can be removed from the transfer resin sheet 10.

[0172] The transfer resin sheet 10 obtained by pre-shaping and removing the support layer 14 is as follows: Figure 6 It is attached to the object to be coated 20 as shown in (c). There is no particular limitation on the method of attaching the transfer resin sheet 10 to the object to be coated 20; it can be done manually using a brush or similar applicator, or by using a laminating device. Since the transfer resin sheet 10 is pre-shaped to correspond to the surface shape of the object to be coated 20, it can be easily attached to the object to be coated 20 even by manual application.

[0173] If a transfer resin sheet 10 is attached to the object to be coated 20, then the following steps are as follows: Figure 6 As shown in (d), the coating layer 11 is cured, and a coating is formed on the workpiece 20 using the coating layer 11. The coating layer 11 can be cured by heating, by irradiation with active energy rays, or by using moisture. Details of the heating and irradiation conditions with active energy rays are as described above. In addition, the transfer layer 12 can be peeled off from the coating layer 11, thereby removing the transfer layer 12 from the workpiece 20. The transfer layer 12 can also be removed before the coating layer 11 is cured, but it is preferable to remove it after the coating layer 11 is cured.

[0174] Example

[0175] The present invention will now be described in more detail by way of examples, but the invention is not limited by these examples.

[0176] The measurement and evaluation methods of this invention are described below.

[0177] <Tackiness value of coating layer>

[0178] The tack value of the coating layer was measured according to the following procedure. Specifically, the probe was placed in a probe initial tack tester (Yubeam Co., Ltd. TA-500) with the adhesive side of the coating transfer-curing resin in contact with the probe. The measurement was performed under the following conditions, and the maximum load at peeling was used as the tack value for evaluation.

[0179] Probe diameter: 5mm, speed: 10mm / s, contact load: 100gf, contact time: 1s

[0180] <Tensive elongation at break of the transfer layer>

[0181] The tensile elongation at break of the transfer layer was measured according to the method of JIS K7127. Specifically, the film used for the transfer layer was cut into dumbbell shapes with a width of 10 mm and a mark width of 25 mm, and then mounted into a tensile testing machine. In Examples 1-8 and Comparative Examples 1-2, the film was stretched in a constant temperature bath set to 120°C at a tensile speed of 100 mm / min, and the tensile elongation was calculated using the following formula based on the displacement of the point where the film breaks. In Examples 9-12 and Comparative Examples 3-4, the film was stretched in a constant temperature bath set to 100°C at a tensile speed of 100 mm / min, and the tensile elongation was calculated using the following formula based on the displacement of the point where the film breaks. It should be noted that the width of the fixture was set to be the same as the width of the mark. The tensile elongation at break of the transfer layer was measured for both MD and TD.

[0182] Elongation at break (%) = (Displacement at break / Marking width) × 100

[0183] Scratch resistance

[0184] The measurements were performed using a pencil scratching method in accordance with JIS K5600-5-4.

[0185] Specifically, the test samples were prepared according to the following guidelines. In Example 7, after the prepared transfer resin sheet was attached to a sintered coated plate, it was subjected to ultraviolet irradiation at 3000 mJ / cm using a 365 nm LED lamp. 2 After curing under certain conditions, the transfer film was peeled off to prepare an evaluation sample. In examples other than Example 7, after attaching the transfer resin sheet to the sintered coated plate, the transfer film was peeled off to transfer the coating layer to the sintered coated plate. The sintered coated plate was then placed in an oven at 160°C for 1 hour to allow it to be thermo-cured.

[0186] For the surface of the cured paint layer, a pencil is held at a 45° angle, a load of 1 kg is applied, and the surface is scratched for 10 mm. The scratches are then checked, and the highest pencil hardness without scratches is used as the rating. The pencil used is "Mitsubishi Pencil uni (manufactured by Mitsubishi Pencil Co., Ltd.) certified by the Japan Paint Inspection Association".

[0187] <Adhesion>

[0188] The adhesion was evaluated according to the following procedure. First, water containing 0.5% polyalkyl ether surfactant was blown onto the sintered coated plate. Next, the plate was positioned so that the adhesion surface of the transfer resin sheet coincided with that of the sintered coated plate. Then, the transfer layer was rubbed off using a brush, thereby expelling water while pressing it together. After pressing, the adhesion was evaluated based on the peeling behavior when the transfer layer was removed.

[0189] A: There is no peeling or flaking of the paint layer, and it can be applied smoothly.

[0190] B: Lifting / peeling occurs in the coating layer, preventing smooth adhesion.

[0191] Vacuum forming capability

[0192] The vacuum forming properties of the transfer resin sheets produced in the various embodiments and comparative examples were evaluated by TOM molding, as shown below.

[0193] In a TOM molding machine (manufactured by Fuse Vacuum Co., Ltd., trade name "NGF-0709-S") consisting of an upper and lower chamber, a substrate (ASONE test sheet cartridge) was placed on an upper and lower lifting platform. A curable resin sheet was then placed on a sheet clamping frame of the molding machine, with the coating layer on the bottom and the transfer layer on the top. Next, the vacuum level in the upper and lower chambers was reduced to below 0.0 kPa, and the temperature of the transfer resin sheet was heated to 120°C. In Examples 9-12 and Comparative Examples 3-4, the temperature of the transfer resin sheet was 100°C. The substrate was then raised, and the substrate and the transfer resin sheet were pressed together. Compressed air was then introduced only into the upper chamber and held for 5 seconds. The upper and lower chambers were then opened to atmospheric pressure, resulting in a laminate consisting of the substrate and the transfer resin sheet. The obtained laminates were observed, and their vacuum formability was evaluated according to the following criteria.

[0194] A: The transfer resin sheet follows the three-dimensional shape of the object being coated, resulting in a uniform and tight fit.

[0195] B: The transfer resin sheet cannot perfectly follow the three-dimensional shape of the object being coated, resulting in breakage. Alternatively, wrinkles may form within the sheet itself.

[0196] - The transfer resin sheet has deformed and cannot be fixed using the sheet clamps of the molding machine, so it cannot be evaluated.

[0197] The components used in the examples and comparative examples, and the films used in the transfer layers, are described below.

[0198] <(Meth)acrylic resin (A) and plasticized resin (a)>

[0199] The substances listed in Table 1 below were used as acrylic polyols, reactive polymers containing acryloyl groups, and polycarbonate diols.

[0200]

[0201] Blocked Isocyanate (B)

[0202] Hexamethylene diisocyanate-based blocked isocyanate (HDI series), manufactured by Mitsui Chemicals Co., Ltd., "Takenet B-882N", blocking agent: 2-butanone oxime (MEKO), NV=70%, solvent: naphtha, containing a small amount of carbamate catalyst.

[0203] <Photoradical polymerization initiator (C)>

[0204] Acetophenone compounds, manufactured by BASF as "Omnirad 1173" (NV=100% by mass).

[0205] Pigment (D)

[0206] Pigment dispersion manufactured by Nihon Bix Co., Ltd., "NSP-UP 841B", effective pigment concentration = 9% by mass, NV = 24% by mass.

[0207] <Transfer Layer Film>

[0208] Unstretched cyclic polyolefin film (Decofit Q16CK, manufactured by Higashi Resha, 100μm thickness)

[0209] Unstretched multilayer polybutylene terephthalate film

[0210] Unstretched multilayer olefin membrane 1 (Okamoto Co., Ltd. "Convini PP", thickness 100μm)

[0211] Unstretched multilayer olefin membrane 2 (Okamoto Co., Ltd. "Convini PE", thickness 100μm)

[0212] Unstretched polyethylene terephthalate film (Kaneron KA-20 manufactured by Shinei Kasei Co., Ltd., 100μm thick)

[0213] Biaxially stretched polyethylene terephthalate film (Toyobo Cosmopolitan E7004)

[0214] [Example 1]

[0215] According to the formulation described in Table 2, 71 parts by weight of acrylic polyol (A1), 9 parts by weight of acrylic polyol (a1-(1)) and 20 parts by weight of blocked isocyanate (B) were mixed while stirring thoroughly to prepare a coating liquid of curable resin composition.

[0216] The coating solution was applied to the smooth surface of the unstretched cyclic polyolefin film (manufactured by Higashi Rei Co., Ltd., "Decofit Q16CK") constituting the transfer layer using a coater. Next, a pre-drying process was performed at a drying temperature of 60°C for 30 minutes, followed by a formal drying process at a drying temperature of 90°C for 30 minutes, resulting in a transfer resin sheet with a coating layer of 50 μm thickness formed on the transfer layer. During the above drying process, the solvent was removed from the coating solution, resulting in a coating layer with the formulation described in Table 3.

[0217] [Examples 2-5, 7-8, Comparative Examples 1-2]

[0218] As shown in Table 2, the formulation of the curing resin composition used in the coating liquid and the film used in the transfer layer were changed. Otherwise, the procedure was the same as in Example 1 to obtain a transfer resin sheet. It should be noted that Example 5 also prepared a transfer resin sheet using the pigments described in Table 1.

[0219] [Example 6]

[0220] An unstretched multilayer polybutylene terephthalate film was used as the transfer layer film, and the formulation of the curing resin composition used in the coating liquid was changed as shown in Table 2. Otherwise, a transfer-type curing resin sheet for coating was prepared using the same method as in Example 1. It should be noted that the unstretched multilayer polybutylene terephthalate film was prepared according to the following guidelines.

[0221] The raw material for the skin layer is prepared according to the following principles. 100 parts by weight of polybutylene terephthalate resin (manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name "Nobaduran 5010CS") and a nucleating agent (bis(4-methylbenzyl)sorbitol, T...) m =200℃ (Shin Nippon Rikka Co., Ltd., trade name: Gel-Oil E-200) 5 parts by mass were blended, and then melt-blended and granulated using a twin-screw extruder at a barrel temperature of 250℃ to produce a nucleating agent masterbatch with a nucleating agent concentration of 5% by mass. Next, the polybutylene terephthalate described above was blended with the nucleating agent masterbatch and the result was used as a raw material. Regarding the amount of nucleating agent added, the above-mentioned nucleating agent masterbatch was blended in such a way that the amount of nucleating agent added was 3 parts by mass relative to 100 parts by mass of polybutylene terephthalate, that is, the amount of nucleating agent added was 1500 ppm.

[0222] The core layer is made of high-density polyethylene resin (produced by Polyester Company of Japan, "Nobatet HD").

[0223] Using a 3-layer T-die forming machine with 3 extruders of 40mm screw diameter, each raw material was fed into each extruder. Under the conditions of forming temperature of 250℃, cold hardening roll temperature of 80℃, and air chamber static pressure of 15mmH2O, a multilayer unstretched polybutylene terephthalate film (multilayer PBT film, thickness 200μm) was obtained, consisting of two skin layers of 50μm thick PBT resin and a core layer of 90μm thick polyethylene resin.

[0224] [Example 9]

[0225] The tensile elongation at break of the transfer layer was measured at 100°C. An unstretched multilayer olefin film 1 (combini PP manufactured by Okamoto Co., Ltd., with a thickness of 100 μm) was used as the transfer layer film. The transfer resin sheet was prepared by the same method as in Example 1, except that no formal drying process was performed (drying temperature 90°C, drying time 30 minutes).

[0226] [Example 10]

[0227] The tensile elongation at break of the transfer layer was measured at 100°C. An unstretched multilayer olefin film 2 (combini PE manufactured by Okamoto Co., Ltd., with a thickness of 100 μm) was used as the transfer layer film. The transfer resin sheet was prepared by the same method as in Example 2, except that no formal drying process was performed (drying temperature 90°C, drying time 30 minutes).

[0228] [Example 11]

[0229] The tensile elongation at break of the transfer layer was measured at 100°C. An unstretched polyethylene terephthalate film (Kaneron KA-20 manufactured by Jinei Kasei Co., Ltd., with a thickness of 100 μm) was used as the transfer layer film. The transfer resin sheet was prepared by the same method as in Example 3, except that no formal drying process was performed (drying temperature 90°C, drying time 30 minutes).

[0230] [Example 12]

[0231] The tensile elongation at break of the transfer layer was measured at 100°C. A biaxially stretched polyethylene terephthalate film (Toyobo Cosmopolitan "Cosmopolitan E7004") was used as the transfer layer film. The formulation of the curing resin composition used in the coating liquid was changed as shown in Table 3. Otherwise, the transfer resin sheet was prepared by the same method as in Example 1.

[0232] [Comparative Example 3]

[0233] An unstretched multilayer olefin film 1 (Okamoto Co., Ltd. "Convini PE", thickness 100 μm) was used as the transfer layer film, and the tensile elongation at break of the transfer layer was measured at 100°C. The transfer resin sheet was prepared by the same method as Comparative Example 1, without performing a formal drying process (drying temperature 90°C, drying time 30 minutes).

[0234] [Comparative Example 4]

[0235] An unstretched multilayer olefin film 1 (Okamoto Co., Ltd. "Convini PE", thickness 100 μm) was used as the transfer layer film, and the tensile elongation at break of the transfer layer was measured at 100°C. The transfer resin sheet was prepared by the same method as Comparative Example 2, without performing a formal drying process (drying temperature 90°C, drying time 30 minutes).

[0236]

[0237]

[0238] Table 4 below shows the content of each component based on the total solid content of the curable resin composition in Examples 1-8 and Comparative Examples 1-2. In Example 5, the amount of active ingredient in the pigment is 2% by mass based on the total solid content of the curable resin composition.

[0239]

[0240] In the above embodiments, since the tack value of the coating layer on the adhesion side at 23°C is limited to a certain range, it is possible to manufacture transfer resin sheets with excellent scratch resistance and adhesion. Furthermore, in Examples 1-7 and 9-11, since a transfer layer with high elongation at break at 120°C or 100°C is used, vacuum forming properties are good, the transfer resin sheet follows the three-dimensional shape of the coated object, and can be uniformly adhered, allowing for the formation of a suitable coating from the resin sheet using vacuum forming.

[0241] In contrast, in Comparative Examples 1 and 3, the coating layer had a low tack value on the adhesion side at 23°C, resulting in insufficient adhesion to the substrate and failure to adhere smoothly. Furthermore, in Comparative Examples 2 and 4, the coating layer had a high tack value on the adhesion side at 23°C, but insufficient hardness, resulting in poor scratch resistance.

[0242] Explanation of reference numerals in the attached figures

[0243] 10. Transfer-type curable resin sheets for coating

[0244] 11. Coating layer

[0245] 12 transfer layers

[0246] 13. Release film

[0247] 14 Support Layer

[0248] 20 Painted Objects

[0249] 30 TOM molding device

[0250] 31 upper box

[0251] 32 lower box

[0252] 35. Lifting Platform

[0253] 40 Fixtures

Claims

1. A transfer-curable resin sheet for coating, comprising a coating layer and a transfer layer, the coating layer comprising a curable resin composition capable of being cured by heat, moisture or active energy rays, and the transfer layer comprising a thermoplastic resin. The adhesive value of the side of the coating layer opposite to the side provided with the transfer layer is 300 N / cm at 23°C 2 above and 4000 N / cm 2 below.

2. The coating transfer-curable resin sheet according to claim 1, wherein the MD and TD tensile elongation at break of the transfer layer at 120°C are both above 500%.

3. The coating transfer-curable resin sheet according to claim 1 or 2, wherein the MD and TD tensile elongation at break of the transfer layer at 100°C are both above 500%.

4. The coating transfer-type curable resin sheet according to any one of claims 1 to 3, wherein the curable resin composition comprises a (meth)acrylic resin (A) having a weight-average molecular weight of 100,000 or more and 1,000,000 or less, being in solid form, and having a plurality of functional groups.

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

6. The coating transfer-type curable resin sheet according to claim 4, wherein the (meth)acrylic resin (A) is a polymer (A2) having (meth)acryloyl groups. The curable resin composition contains a free radical polymerization initiator (C) that generates free radicals through heat or active energy rays.

7. A method for forming a coating, comprising attaching a coating transfer-type curable resin sheet as described in claim 1 or 2 to a body to be coated, and then forming a coating by curing the coating layer.

8. The coating formation method according to claim 7, wherein the transfer layer is peeled off from the coating layer, thereby removing the transfer layer from the coated body.

Images