Thermal transfer foil

Abstract

The invention provides a thermal transfer foil capable of ensuring solvent resistance and wear resistance of a transfer layer attached to an object. A thermal transfer foil (100) is provided with a base material (4) and a transfer layer (10) disposed on the base material (4). The transfer layer (10) is provided with a release layer (1), a color layer (2), and an adhesive layer (3), which are laminated in this order in the vicinity of a substrate (4). The release layer (1) contains an isocyanate compound (A) and a polyol compound (B). The isocyanate compound (A) contains a first isocyanate compound (A1) and a second isocyanate compound (A2), which are different from each other. The first isocyanate compound (A1) does not have an isocyanate group terminated with a blocking agent. The second isocyanate compound (A2) has an isocyanate group terminated with a blocking agent.

Description

TECHNICAL FIELD

[0001] Generally, the present application relates to a heat transfer foil, and more particularly, to a heat transfer foil used for imparting decoration to an object. BACKGROUND

[0002] Patent Literature 1 relates to a transfer foil used for close contact with the outer peripheral surface of a round bar having a first outer peripheral surface and a second outer peripheral surface having different taper angles, and discloses that the transfer foil has a base sheet and a transfer layer laminated on the base sheet, and the transfer layer has a release layer for protecting the surface, an ink layer forming a pattern, and an adhesive layer, etc.

[0003] PRIOR ART DOCUMENT

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2020-163861 SUMMARY

[0006] An object of the present disclosure is to provide a heat transfer foil capable of ensuring the solvent resistance and the abrasion resistance of a transfer layer attached to an object.

[0007] A heat transfer foil of one embodiment of the present disclosure includes a base material and a transfer layer provided over the base material. The transfer layer includes, in order close to the base material, a release layer, a color layer, and an adhesive layer. The release layer contains an isocyanate compound (A) and a polyol compound (B) having thermoplasticity. The isocyanate compound (A) contains a first isocyanate compound (A1) and a second isocyanate compound (A2) which are different from each other. The first isocyanate compound (A1) does not have an isocyanate group blocked with a blocking agent. The second isocyanate compound (A2) has an isocyanate group blocked with a blocking agent. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a schematic cross-sectional view of a heat transfer foil of one embodiment of the present disclosure.

[0009] Figure 2 is a schematic cross-sectional view of a process of transferring a heat transfer foil of one embodiment of the present disclosure.

[0010] Figure 3 is a schematic cross-sectional view of a process of transferring a heat transfer foil of one embodiment of the present disclosure. Figure 2 is a schematic cross-sectional view of a process of transferring a heat transfer foil of one embodiment of the present disclosure. DETAILED DESCRIPTION

[0011] [EMBODIMENT]

[0012] The following describes embodiments of the present disclosure. Note that the present disclosure is not limited to the embodiments described below. The embodiments described below are merely examples of various embodiments of the present disclosure and various changes can be made to the embodiments in accordance with design as long as the objects of the present disclosure are achieved. In addition, the scope of the present disclosure is not limited by the process of development described below. Furthermore, the mechanisms shown in the following description are speculative and the present disclosure is not limited to the mechanisms shown below.

[0013] (SUMMARY)

[0014] First, the process of completing the present disclosure is described.

[0015] Conventionally, in order to improve the recognition and added value of a product, a decoration is applied to the outer surface of a shaft or the like.

[0016] As a method of applying the decoration, in addition to a method of providing a pattern or the like by painting or printing, a method of pasting a decoration using a thermal transfer foil has been proposed (Patent Document 1). The thermal transfer foil has the advantages of high freedom of decoration and easy operation. In particular, a shaft requires a character such as a logo of a product and requires an appearance design composed of various patterns and colors, and therefore it is preferable to adopt a decoration using a thermal transfer foil.

[0017] A conventional thermal transfer foil has a transfer film composed of a plurality of layers such as a release layer, an ink layer, and an adhesive layer, and a decoration is performed by attaching the transfer film to a shaft or the like. In general, a shaft or the like to which the transfer film is attached is exposed to a severe environment. Therefore, an overcoat layer is sometimes applied in order to protect the transfer film. However, the process of applying the overcoat layer has a problem of requiring time and cost.

[0018] In view of the above problem, the inventors have conducted intensive research and development, and as a result, have developed a thermal transfer foil 100 capable of ensuring the solvent resistance and wear resistance of a transfer layer 10 attached to an object 20.

[0019] The thermal transfer foil 100 of the present embodiment has a substrate 4 and a transfer layer 10 disposed on the substrate 4. The transfer layer 10 has a release layer 1, a color layer 2, and an adhesive layer 3 (see FIG. 1) sequentially stacked in this order close to the substrate 4. Figure 1 The release layer 1 contains an isocyanate compound (A) and a polyol compound (B) having thermoplasticity. The isocyanate compound (A) contains a first isocyanate compound (A1) and a second isocyanate compound (A2) that are different from each other. The first isocyanate compound (A1) does not have an isocyanate group blocked by a blocking agent. The second isocyanate compound (A2) has an isocyanate group blocked by a blocking agent.

[0020] The thermal transfer foil 100 functions as described above by having the above-described configuration, and although the reason is not necessarily clear, it can be assumed as follows.

[0021] The release layer 1 contains the first isocyanate compound (Al). Therefore, by attaching the transfer layer 10 to the object 20 while heating it, the first isocyanate compound (Al) contained in the release layer 1 can react with the polyol compound (B). Thus, the wear resistance of the release layer 1 can be improved.

[0022] Then, after the transfer layer 10 is attached to the object 20, by further heating the transfer layer 10, the blocking agent possessed by the second isocyanate compound (A2) can be efficiently detached. In this case, the reaction of the second isocyanate compound (A2) with the polyol compound (B) can efficiently proceed. Therefore, the curing of the release layer 1 can further proceed. Thus, the wear resistance of the release layer 1 can be further improved, and the solvent resistance can be improved.

[0023] According to such a mechanism, the thermal transfer foil 100 can ensure the solvent resistance and the wear resistance of the transfer layer 10 attached to the object 20.

[0024] (Transfer Layer)

[0025] The layer possessed by the transfer layer 10 will be described.

[0026] <Release Layer>

[0027] As described above, the transfer layer 10 possesses the release layer 1. The release layer 1 is overlaid on the substrate 4. The thickness of the release layer 1 is, for example, 2 μm to 6 μm. In this case, the solvent resistance and the wear resistance of the release layer 1 can be sufficiently ensured. The thickness is preferably 3 μm or more. The thickness is preferably 5 μm or less.

[0028] In addition, the release layer 1 contains the isocyanate compound (A) and the polyol compound (B). Thus, the release layer 1 can be cured. Also, the isocyanate compound (A) contains both the first isocyanate compound (Al) and the second isocyanate compound (A2). Thus, the solvent resistance and the wear resistance of the release layer 1 can be improved. As a result, the solvent resistance and the wear resistance of the transfer layer 10 attached to the object 20 can be ensured.

[0029] The content ratio of the isocyanate compound (A) with respect to the polyol compound (B) is preferably 10 mass% to 30 mass%. In this case, the solvent resistance and the wear resistance of the release layer 1 can be further improved. The content ratio is more preferably 15 mass% or more. The content ratio is further preferably 25 mass% or less.

[0030] <First Isocyanate Compound>

[0031] As described above, the isocyanate compound (A) contains the 1st isocyanate compound (Al). The 1st isocyanate compound (Al) does not have an isocyanate group blocked by a blocking agent. In this case, the isocyanate group of the 1st isocyanate compound (Al) can easily react with the hydroxyl group of the polyol compound (B). Therefore, when the transfer layer 10 is attached to the object 20 while being heated, the 1st isocyanate compound (Al) contained in the release layer 1 can react with the polyol compound (B). Thus, the wear resistance of the release layer 1 can be improved. Note that the heating performed when the transfer layer 10 is attached to the object 20 means, for example, heating in the range of 190°C to 230°C. In addition, since the time required for attaching the transfer layer 10 to the object 20 is short, the blocking agent of the 2nd isocyanate compound (A2) is unlikely to be removed at this time.

[0032] The molecular form of the 1st isocyanate compound (Al) is not particularly limited. For example, the 1st isocyanate compound (Al) contains at least one selected from the group consisting of a monomer, an oligomer, a prepolymer, and a polymer.

[0033] As described above, the 1st isocyanate compound (Al) can contain a monomer. The monomer contained in the 1st isocyanate compound (Al) is not particularly limited in the number of isocyanate groups in one molecule, but is preferably 2. In other words, the 1st isocyanate compound (Al) preferably contains a 2-functional isocyanate monomer. In this case, the wear resistance of the release layer 1 can be further improved. Furthermore, the 2-functional isocyanate monomer contains at least one selected from the group consisting of an aliphatic diisocyanate monomer, a cycloaliphatic diisocyanate monomer, and an aromatic diisocyanate monomer. The 2-functional isocyanate monomer preferably contains at least one of an aliphatic diisocyanate monomer and a cycloaliphatic diisocyanate monomer. In this case, the wear resistance of the release layer 1 can be further improved.

[0034] The aliphatic diisocyanate monomer contains, for example, at least one selected from the group consisting of butane diisocyanate, pentane diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate. In addition, the alicyclic diisocyanate monomer contains, for example, at least one selected from the group consisting of 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate), hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and 1,4-cyclohexane diisocyanate. Further, the aromatic diisocyanate monomer contains, for example, at least one selected from the group consisting of phenylene-1,4-diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, naphthalene-1,5-diisocyanate, diphenylmethane-2,2'-diisocyanate, diphenylmethane-2,4'-diisocyanate, and diphenylmethane-4,4'-diisocyanate. Among these, the first isocyanate compound (A1) particularly preferably contains at least one of hexamethylene diisocyanate and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate). In this case, the wear resistance of the release layer 1 can be particularly improved.

[0035] As described above, the first isocyanate compound (A1) can contain at least one of an oligomer, a prepolymer, and a polymer. In other words, the first isocyanate compound (A1) can contain a polyisocyanate resin. In this case, the wear resistance of the release layer 1 can be further improved. The polyisocyanate resin is a compound having two or more isocyanate groups in one molecule. The number of isocyanate groups in one molecule of the polyisocyanate resin is not particularly limited, and can be appropriately adjusted. Thereby, the curability of the release layer 1 can be adjusted. In addition, the polyisocyanate resin can have an isocyanate group at a molecular terminal thereof, or can have an isocyanate group in the inside of the molecule thereof.

[0036] Note that the first isocyanate compound (A1) preferably contains both the monomer and the polyisocyanate resin. In this case, the wear resistance of the release layer 1 can be further improved. Note that the first isocyanate compound (A1) particularly preferably contains hexamethylene diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, and a polyisocyanate resin.

[0037] The content ratio of the first isocyanate compound (A1) with respect to the isocyanate compound (A) is preferably 10 to 30% by mass. If the content ratio is 15% by mass or more, the wear resistance of the release layer 1 can be further improved. If the content ratio is 25% by mass or less, the transferability of the thermal transfer foil 100 can be ensured.

[0038] It should be noted that, in the case where the release layer 1 does not contain the first isocyanate compound (Al) but contains only the second isocyanate compound (A2) as the isocyanate compound (A), there is a tendency that the second isocyanate compound (A2) contained in the release layer 1 seeps out from the release layer 1 and can come into contact with the color layer 2 or the adhesive layer 3. In contrast, in the present disclosure, the isocyanate compound (A) contains the second isocyanate compound (A2) in addition to the first isocyanate compound (Al). Therefore, the wear resistance of the release layer 1 can be sufficiently ensured, and the seepage of the first isocyanate compound (Al) from the release layer 1 can be alleviated.

[0039] In addition, in the case where the surface of the substrate 4, which overlaps with the release layer 1, has unevenness, for example, in the case of a rough surface, if the substrate 4 is peeled from the release layer 1 (see Figure 3 ), the unevenness of the substrate 4 is transferred to the release layer 1, and the surface of the release layer 1 can have unevenness. However, in the case where the release layer 1 does not contain the first isocyanate compound (Al) but contains only the second isocyanate compound (A2) as the isocyanate compound (A), when the heated transfer roller 6 is pressed against the substrate 4 or the like to transfer the transfer layer 10 to the object 20 (see Figure 2 ), the surface of the substrate 4 easily becomes smooth along with the heat-curing of the second isocyanate compound (A2). As a result, the unevenness of the surface of the substrate 4 is not easily transferred to the release layer 1. In contrast, in the present disclosure, the isocyanate compound (A) contains the second isocyanate compound (A2) in addition to the first isocyanate compound (Al). Thus, since the coating strength of the release layer 1 is improved, the unevenness of the surface of the substrate 4 can be maintained after the heat-curing of the second isocyanate compound (A2), and the unevenness of the substrate 4 can be transferred to the release layer 1.

[0040] <Second Isocyanate Compound>

[0041] As described above, the isocyanate compound (A) contains the second isocyanate compound (A2). At least a part of the isocyanate groups of the second isocyanate compound (A2) is blocked by a blocking agent. That is, the second isocyanate compound (A2) is a blocked isocyanate compound.

[0042] As described above, if the second isocyanate compound (A2) is heated, the blocking agent can be efficiently detached. In this case, after the transfer layer 10 is attached to the object 20, the curing of the release layer 1 can be promoted by heating the transfer layer 10. Thus, the wear resistance of the release layer 1 can be improved.

[0043] More specifically, the peeling layer 1, for which the abrasion resistance is improved by attaching the transfer layer 10 to the object 20 while heating the transfer layer 10, is heated, whereby the reaction of the second isocyanate compound (A2) and the polyol compound (B) proceeds, and the curing of the peeling layer 1 proceeds, whereby the abrasion resistance of the peeling layer 1 is further improved. Note that the heating performed after attaching the transfer layer 10 to the object 20 means, for example, heating in the range of 80°C to 150°C.

[0044] In addition, the second isocyanate compound (A2) can have an isocyanate group that is not capped by the capping agent, as long as at least a part of the isocyanate groups are capped by the capping agent. The capping agent contains, for example, at least one selected from the group consisting of active methylene-based capping agents, oxime-based capping agents, alcohol-based capping agents, acid amide-based capping agents, acid imide-based capping agents, phenol-based capping agents, amine-based capping agents, imidazole-based capping agents, and pyrazole-based capping agents. These capping agents can be used singly or in combination of two or more.

[0045] In addition, the temperature at which the blocking agent is released from the second isocyanate compound (A2) can be adjusted by appropriately selecting the blocking agent. Thus, the temperature at which the release layer 1 is cured can be adjusted. Note that the temperature at which the blocking agent is released from the second isocyanate compound (A2) is preferably 80°C to 120°C. By making the temperature at which the blocking agent is released 80°C or higher, the release layer 1 can be cured insufficiently until the transfer layer 10 is attached to the object 20. Thus, the transferability of the heat transfer foil 100 can be sufficiently ensured. In addition, by making the temperature at which the blocking agent is released 120°C or lower, the release layer 1 can be cured at a temperature that does not impair the quality of the object 20. Note that the temperature at which the blocking agent is released is preferably 110°C or lower, more preferably 100°C or lower, and further preferably 90°C or lower. Note that the temperature at which the blocking agent is released from the second isocyanate compound (A2) can be confirmed as follows. First, a mixture of the polyol compound (B) and the second isocyanate compound (A2) is applied to a substrate (a sample coating plate or the like), and the coating film is formed by heating at any temperature in the range of 90°C to 120°C for 60 minutes. Then, the formed coating film is cooled to room temperature. Next, a rubbing test is performed on the surface of the coating film by applying a load of 150 g with a cotton swab dipped in methyl ethyl ketone. The rubbing test is performed by repeatedly rubbing with the cotton swab for 50 times or until the surface of the substrate is exposed by the dissolution of the coating film, with one round trip of 20 mm as one time. In the case where the surface of the substrate is not exposed even after 50 times of rubbing, it is determined that the curing has progressed completely due to the release of the blocking agent. In this case, the heating temperature after the application of the mixture is lowered by 1°C, the coating film is formed again, and the rubbing test is performed again. In contrast, in the case where the surface of the substrate is exposed after less than 50 times of rubbing, it is determined that the release of the blocking agent has not progressed sufficiently and the curing has not progressed. In this case, the heating temperature after the application of the mixture is increased by 1°C, the coating film is formed again, and the rubbing test is performed again. According to the above method, the lowest temperature in the heating temperature at which the surface of the substrate is not exposed even after 50 times of rubbing with the cotton swab dipped in methyl ethyl ketone is determined as the temperature at which the blocking agent is released from the second isocyanate compound (A2).

[0046] Further, the molecular form of the second isocyanate compound (A2) is not particularly limited. For example, the second isocyanate compound (A2) contains at least one selected from the group consisting of a monomer, an oligomer, a prepolymer, and a polymer. Among these, the second isocyanate compound (A2) preferably contains at least one of a prepolymer and a polymer. In other words, the second isocyanate compound (A2) preferably contains a blocked polyisocyanate resin. In this case, the wear resistance and the solvent resistance of the release layer 1 can be further improved. The blocked polyisocyanate resin is a compound having two or more isocyanate groups in one molecule, at least one of which is blocked with a blocking agent.

[0047] The content ratio of the second isocyanate compound (A2) with respect to the isocyanate compound (A) is preferably 70 to 90% by mass. In this case, the wear resistance and the solvent resistance of the release layer 1 can be further improved. The content ratio is more preferably 75% by mass or more. The content ratio is more preferably 85% by mass or less.

[0048] ≪Polyol Compound≫

[0049] As described above, the release layer 1 contains a polyol compound (B). As described above, with respect to the release layer 1, by attaching the transfer layer 10 to the object 20 while heating, the first isocyanate compound (Al) can be reacted with the polyol compound (B). Note that, at the stage of attaching the transfer layer 10 to the object 20, the first isocyanate compound (Al) can be partially reacted with the polyol compound (B), or the entire first isocyanate compound (Al) can be reacted with the polyol compound (B).

[0050] The polyol compound (B) has thermoplasticity. In other words, the polyol compound (B) is a thermoplastic resin having a hydroxyl group. For example, the polyol compound (B) contains at least one selected from the group consisting of a polyester-based polyol, an acrylic-based polyol, a polyether-based polyol, a polyolefin-based polyol, a fluorine-based polyol, a polycarbonate-based polyol, and a vinyl chloride-vinyl acetate copolymer-based polyol. Further, the polyol compound (B) particularly preferably contains a vinyl chloride-vinyl acetate copolymer-based polyol (vinyl chloride-vinyl acetate polyol), in which case, the solvent resistance and the wear resistance of the release layer 1 can be particularly improved.

[0051] Note that, in the present disclosure, the vinyl chloride-vinyl acetate copolymer-based polyol refers to a vinyl chloride-vinyl acetate copolymer having two or more hydroxyl groups in one molecule. The method for producing the vinyl chloride-vinyl acetate polyol is not particularly limited, but for example, a vinyl chloride-vinyl acetate polyol can be produced by imparting a hydroxyl group by chemically modifying a part of a vinyl chloride-vinyl acetate copolymer. Alternatively, a vinyl chloride-vinyl acetate polyol can be produced by saponifying a vinyl chloride-vinyl acetate copolymer to cause an acetyl group to be separated from a part of the vinyl acetate to generate a hydroxyl group.

[0052] The content ratio of the polyol compound (B) with respect to the entirety of the release layer 1 is preferably 55 to 65% by mass. In this case, the solvent resistance and the abrasion resistance of the release layer 1 can be further improved. The content ratio is more preferably 60% by mass or more. The content ratio can be 70% by mass or less.

[0053] In addition, the mass ratio of the isocyanate compound (A) to the polyol compound (B) is preferably 10:90 to 30:70. In this case, the solvent resistance and the abrasion resistance of the release layer 1 can be improved. The mass ratio is more preferably 15:85 to 25:75.

[0054] < solvent >

[0055] In producing the release layer 1, a solvent (C) is sometimes used. Therefore, the solvent (C) can sometimes remain in the release layer 1. The solvent (C) is not particularly limited as long as it is a solvent used as a solvent for a paint, and for example, contains at least one selected from the group consisting of an ester compound, an ether compound, a ketone compound, a hydrocarbon compound, and a glycol ether compound. The hydrocarbon-based compound contains at least one of an aliphatic hydrocarbon compound and an aromatic hydrocarbon compound. Note that the solvent (C) preferably contains at least one of a ketone compound and an aromatic hydrocarbon compound, and more specifically, preferably contains at least one of isophorone, Solvesso 150, and cyclohexanone.

[0056] The content ratio of the solvent with respect to the entirety of the release layer 1 is preferably 15% by mass or less. In this case, the transferability and the print adaptability of the thermal transfer foil 100 can be sufficiently ensured.

[0057] < additive >

[0058] The release layer 1 contains an additive (D) in addition to the isocyanate compound (A), the polyol compound (B), and the solvent (C), for example. As the additive (D), for example, a defoaming agent, a leveling agent, or the like can be given. The defoaming agent contains a silicone resin, for example. The leveling agent contains a silicone resin, for example.

[0059] < color layer >

[0060] As described above, the transfer layer 10 is provided with the color layer 2. The color layer 2 is layered on the release layer 1. The color layer 2 can include a plurality of layers. The thickness of each layer included in the color layer 2 is 2 μm to 6 μm, respectively. In this case, the solvent resistance and the abrasion resistance of the color layer 2 can be sufficiently ensured.

[0061] For example, the color layer 2 contains the isocyanate compound (E) and the polyol compound (F). In this case, the abrasion resistance and the solvent resistance of the color layer 2 can be improved.

[0062] The isocyanate compound (E) preferably does not contain the isocyanate compound (El) which does not have an isocyanate group blocked by a blocking agent. In this case, the color layer 2 can be formed on the release layer 1 without being cured. Thus, the transferability of the thermal transfer foil 100 can not be impaired.

[0063] In addition, the isocyanate compound (E) preferably contains the isocyanate compound (E2) which has an isocyanate group blocked by a blocking agent. In this case, the color layer 2 can be cured by heating the transfer layer 10 after the transfer layer 10 is attached to the object 20. Thus, the transferability of the thermal transfer foil 100 can be sufficiently ensured and the solvent resistance and the abrasion resistance of the color layer 2 can be improved.

[0064] Note that the isocyanate compound (E) contained in the color layer 2 is not particularly limited, but for example, the same compound as the isocyanate compound (A) contained in the release layer 1 can be used.

[0065] In addition, the polyol compound (F) contained in the color layer 2 is not particularly limited, but for example, the same compound as the polyol compound (B) contained in the release layer 1 can be used. The color layer 2 preferably contains a vinyl chloride vinyl acetate polyol as the polyol compound (F). In this case, the solvent resistance and the abrasion resistance of the color layer 2 can be improved.

[0066] Further, the color layer 2 can contain at least one selected from a defoaming agent, an adhesion promoter, and a solvent, in addition to the isocyanate compound (E) and the polyol compound (F). As the solvent contained in the color layer 2, the same compound as the solvent (C) which can be contained in the release layer 1 can be used. As the defoaming agent contained in the color layer 2, the same compound as the defoaming agent contained in the release layer 1 can be used. As the adhesion promoter of the color layer 2, the same compound as the adhesion promoter which can be contained in the release layer 1 can be used.

[0067] <Adhesion Layer>

[0068] As described above, the transfer layer 10 is provided with the adhesion layer 3. The adhesion layer 3 is layered on the color layer 2. The thickness of the adhesion layer 3 is 2 μm to 6 μm. In this case, the solvent resistance and the abrasion resistance of the adhesion layer 3 can be sufficiently ensured.

[0069] For example, the adhesive layer 3 contains the isocyanate compound (G) and the polyol compound (H). In this case, the wear resistance and the solvent resistance of the adhesive layer 3 can be improved.

[0070] The isocyanate compound (G) preferably does not contain an isocyanate compound (G1) that does not have an isocyanate group blocked by a blocking agent. In this case, the adhesive layer 3 can be formed without curing on the color layer 2. Thus, the adhesion of the adhesive layer 3 to the object 20 can be further ensured.

[0071] In addition, the isocyanate compound (G) preferably contains an isocyanate compound (G2) that has an isocyanate group blocked by a blocking agent. In this case, after the transfer layer 10 is attached to the object 20, the transfer layer 10 is heated, whereby the adhesive layer 3 can be cured. Thus, the adhesion of the adhesive layer 3 to the object 20 can be ensured and the solvent resistance and the wear resistance of the adhesive layer 3 can be improved.

[0072] Note that the isocyanate compound (G) contained in the adhesive layer 3 is not particularly limited, but for example, the same compound as the isocyanate compound (A) contained in the release layer 1 can be used.

[0073] In addition, the polyol compound (H) contained in the adhesive layer 3 is not particularly limited, but for example, the same compound as the polyol compound (B) contained in the release layer 1 can be used. The adhesive layer 3 preferably contains a vinyl chloride-vinyl acetate polyol as the polyol compound (H). In this case, the solvent resistance and the wear resistance of the adhesive layer 3 can be improved.

[0074] The adhesive layer 3 can contain at least one selected from a defoaming agent, an adhesion promoter, and a solvent, in addition to the isocyanate compound (G) and the polyol compound (H). The solvent contained in the adhesive layer 3 can be the same compound as the solvent (C) that can be contained in the release layer 1. The defoaming agent contained in the adhesive layer 3 can be the same compound as the defoaming agent contained in the release layer 1. The adhesion promoter contained in the adhesive layer 3 can be the same compound as the adhesion promoter that can be contained in the release layer 1.

[0075] (Method for manufacturing thermal transfer foil)

[0076] A method for manufacturing the thermal transfer foil 100 will be described. Note that the method for manufacturing the thermal transfer foil 100 is not limited to the following method, and an appropriate method can be used depending on the usage.

[0077] First, a composition for forming the release layer 1 (hereinafter, composition (L)) is prepared. The composition (L) contains the isocyanate compound (A) and the polyol compound (B), and contains a solvent (C) and the like as necessary. In addition, a composition for forming the color layer 2 (hereinafter, composition (M)) is prepared. The composition (M) contains, for example, an isocyanate compound (E), a polyol compound (F), a solvent, and the like. Then, a composition for forming the adhesive layer 3 (hereinafter, composition (N)) is prepared. The composition (N) contains, for example, an isocyanate compound (G), a polyol compound (H), a solvent, and the like.

[0078] Next, the composition (L) is applied on the substrate 4 to produce a coating film, and the release layer 1 is formed by temporarily leaving the coating film at normal temperature or heating. As the temperature of heating here, a temperature at which the isocyanate compound (A) and the polyol compound (B) do not react is preferred, and for example, less than 80°C is preferred. In addition, as the method of applying the composition (L), there is no particular limitation, but an appropriate method can be applied. As the method of applying the composition (L), for example, screen printing, reverse roll coating, gravure coating, die coating, roll brushing, spraying, air knife coating, curtain coating, and the like can be given.

[0079] Next, the composition (M) is applied on the release layer 1 to produce a coating film, and the color layer 2 is formed by temporarily leaving the coating film at normal temperature or heating. As the temperature of heating here, a temperature at which the isocyanate compound (A) and the polyol compound (B) do not react or, in the case where the composition (M) contains the isocyanate compound (E), a temperature at which the isocyanate compound (E) and the polyol compound (F) do not react is preferred, and for example, less than 80°C is preferred. Thus, the color layer 2 is formed. Note that, as the method of applying the composition (M), the same method as the method of applying the composition (L) can be applied.

[0080] Next, the composition (N) is applied on the color layer 2 to produce a coating film, and the adhesive layer 3 is formed by temporarily leaving the coating film at normal temperature or heating. As the temperature of heating here, a temperature at which the isocyanate compound (A) and the polyol compound (B) do not react, or, in the case where the composition (M) contains the isocyanate compound (E), a temperature at which the isocyanate compound (E) and the polyol compound (F) do not react, or, in the case where the composition (N) contains the isocyanate compound (G), a temperature at which the isocyanate compound (G) and the polyol compound (H) do not react is preferred, and for example, less than 80°C is preferred. Thus, the adhesive layer 3 is formed. Note that, as the method of applying the composition (N), the same method as the method of applying the composition (L) can be applied.

[0081] (Decoration)

[0082] A method of applying a decoration to an object 20 using the thermal transfer foil 100 will be described.

[0083] First, the thermal transfer foil 100 is arranged on the upper side of the object 20 in such a manner that the adhesive layer 3 of the thermal transfer foil 100 opposes the object 20. Next, the transfer layer 10 is transferred to the object 20 in such a manner that the transfer roller 6 is pressed against the base material 4 (see Figure 2 ). At this time, mainly the first isocyanate compound (Al) and the polyol compound (B) can react. Note that the temperature of the transfer roller 6 is not particularly limited, but is, for example, 190°C to 230°C. Thus, the transfer layer 10 attached to the object 20 can be prevented from being damaged. In addition, from the viewpoint of the heat resistance of the base material 4, the heating time at this time is preferably performed for 0.2 seconds to 0.3 seconds. Further, after the transfer in such a manner that the transfer layer 10 contacts the object 20, the base material 4 is peeled from the release layer 1 (see Figure 3 ). In this way, the transfer layer 10 is attached to the object 20. Note that at this time, in the case where the color layer 2 does not contain the isocyanate compound (El), the tackiness of the composition (M) can be suppressed. Thus, when the composition (M) is applied onto the release layer 1 to form the color layer 2, the previously formed release layer 1 can be prevented from being peeled off. Thus, the transfer layer 10 can be further prevented from being damaged. In addition, in the case where the adhesive layer 3 contains the isocyanate compound (Gl), the tackiness of the composition (N) can be suppressed. Thus, when the composition (N) is applied onto the color layer 2 to form the adhesive layer 3, the previously formed release layer 1 can be prevented from being peeled off. Thus, the transfer layer 10 can be further prevented from being damaged.

[0084] Next, the transfer layer 10 is fired by heating the object 20 to which the transfer layer 10 is attached. The method of heating is not particularly limited, but, for example, the object 20 to which the transfer layer 10 is attached can be heated in a heating furnace or the like by being put into the heating furnace. At this time, mainly the second isocyanate compound (A2) and the polyol compound (B) can react. Note that the heating temperature at this time is, for example, 90°C to 120°C. In addition, the heating time is performed for 30 minutes to 90 minutes, and is particularly preferably performed for 90 minutes. If the heating temperature and the heating time are within the above-described ranges, the transfer layer 10 can be sufficiently cured, and as a result, the solvent resistance and the abrasion resistance of the transfer layer 10 can be sufficiently ensured.

[0085] It should be noted that the color layer 2 and the adhesive layer 3 can be cured respectively by performing the firing of the transfer layer 10. In particular, in the case where the color layer 2 contains the isocyanate compound (E2), the isocyanate compound (E2) and the polyol compound (F) can efficiently react. In addition, in the case where the adhesive layer 3 contains the isocyanate compound (G2), the isocyanate compound (G2) and the polyol compound (H) can efficiently react.

[0086] In addition, in the case where the heat resistance of the object 20 is low, even if the object 20 is heated under conditions of 90°C to 120°C, the solvent resistance and the abrasion resistance of the transfer layer 10 can be sufficiently ensured, and thus the degradation of the quality of the object 20 accompanying the heating can be suppressed.

[0087] According to the method as described above, the thermal transfer foil 100 can be transferred to the object 20. It should be noted that the method of transferring the thermal transfer foil 100 to the object 20 is not limited to the method described above, and an appropriate method and conditions can be employed depending on the usage.

[0088] It should be noted that in the case where the transfer layer 10 is attached to the object 20, the transfer layer 10 is exposed to the external environment. In the embodiment, the solvent resistance and the abrasion resistance of the transfer layer 10 attached to the object 20 can be ensured, and thus even if the transfer layer 10 is exposed to the external environment, the transfer layer 10 can have good durability. Thus, the necessity of protecting the transfer layer 10 with an overcoat layer or the like can be reduced, and the process for providing the overcoat layer can be cut down. However, it is not hindered that the transfer layer 10 is protected by being covered with the overcoat layer or the like for the purpose of further improving the durability and the like.

[0089] Example

[0090] Hereinafter, the present disclosure will be further described in detail according to examples, but the present disclosure is not limited to these examples.

[0091] (Composition)

[0092] <Composition for forming a release layer>

[0093] A composition for forming a release layer (hereinafter, referred to as a first composition) was prepared by mixing the components shown in Table 1 at the proportions shown in Table 1. The details of the components are as follows.

[0094] <Non-blocked isocyanate compound>

[0095] • Non-blocked isocyanate compound #1: mixture of hexamethylene diisocyanate and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate) (0.2 mass% of hexamethylene diisocyanate, 0.3 mass% of 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate).

[0096] • Non-blocked isocyanate compound #2: hexamethylene diisocyanate 0.6 mass%, polyisocyanate 85.0 mass%, butyl acetate 14.4 mass%.

[0097] • Non-blocked isocyanate compound #3: xylene diisocyanate 75.0 mass%, ethyl acetate 25.0 mass%.

[0098] • Non-blocked isocyanate compound #4: polyisocyanate 75.0 mass%, ethyl acetate 24.5 mass%, 2,6-di-tert-butyl-4-methylphenol 0.5 mass%.

[0099] < Blocked isocyanate compound >

[0100] • Blocked isocyanate compound #1: blocked isocyanate compound (desorption temperature of blocking agent 110°C) 70.0 mass%, propylene glycol monomethyl ether acetate 30.0 mass%.

[0101] • Blocked isocyanate compound #2: blocked isocyanate compound (desorption temperature of blocking agent 120°C) 55.0 mass%, 1-methoxy-2-propanol 45.0 mass%.

[0102] • Blocked isocyanate compound #3: blocked isocyanate compound (desorption temperature of blocking agent 110°C) 69.6 mass%, dipropylene glycol monomethyl ether 30.0 mass%, residual blocking agent 0.4 mass%.

[0103] • Blocked isocyanate compound #4: blocked isocyanate compound (desorption temperature of blocking agent 110°C) 70.0 mass%, 1-methoxy-2-propyl acetate 28.8 mass%, unreacted residual blocking agent 1.2 mass%.

[0104] < Polyol compound >

[0105] • Polyol compound #1: vinyl chloride-vinyl acetate polyol.

[0106] < Solvent >

[0107] • Solvent #1: mixed solvent of cyclohexanone and isophorone and Solvesso 150 (cyclohexanone 25 mass%, isophorone 25 mass%, Solvesso 150 50 mass%).

[0108] < Additive >

[0109] • Additive #1: defoaming agent (silicone resin (silicone oil)).

[0110] • Additive #2: leveling agent (acrylic polymer).

[0111] <Composition for forming a color layer>

[0112] A composition for forming a color layer (hereinafter, referred to as a second composition) was prepared by mixing the following components.

[0113] • Blocked isocyanate compound (desorption temperature of blocking agent 110°C). 8 mass%.

[0114] • Chlorovinyl vinyl acetate copolymer polyol. 76 mass%.

[0115] • Mixed solvent of cyclohexanone and isophorone and Solvesso 150 (cyclohexanone 25 mass%, isophorone 25 mass%, Solvesso 150 50 mass%). 12 mass%.

[0116] • Defoaming agent (silicone resin (silicone oil)). 2 mass%.

[0117] • Tackifier (silicon dioxide). 2 mass%.

[0118] <Composition for forming an adhesive layer>

[0119] A composition for forming an adhesive layer (hereinafter, referred to as a third composition) was prepared by mixing the following components.

[0120] • Blocked isocyanate compound (desorption temperature of blocking agent 110°C). 8 mass%.

[0121] • Mixed product of chlorovinyl vinyl acetate copolymer and isocyanate compound. 75 mass%.

[0122] • Mixed solvent of cyclohexanone and isophorone and Solvesso 150 (cyclohexanone 25 mass%, isophorone 25 mass%, Solvesso 150 50 mass%). 15 mass%.

[0123] • Defoaming agent (silicone resin (silicone oil)). 2 mass%.

[0124] (Production of a thermal transfer foil)

[0125] A thermal transfer foil was produced from the first composition, the second composition, and the third composition according to the following method.

[0126] First, the first composition was applied to a release film (PET film coated with silicone resin release on both sides: thickness 25 μm) by screen printing to produce a coated film. Next, the coated film was heated by drying with hot air to produce a release layer.

[0127] Next, the second composition is applied on the release layer by screen printing to form a coating film. Next, the coating film is heated by drying with hot air to form a color layer.

[0128] Then, the third composition is applied on the color layer by screen printing to form a coating film. Next, the coating film is heated by drying with hot air to form an adhesive layer.

[0129] The release layer, the color layer, and the adhesive layer are sequentially layered on the release film as described above, whereby a thermal transfer foil is produced.

[0130] (Evaluation of the thermal transfer foil)

[0131] The thermal transfer foil produced is used to transfer the transfer layer to an object (a shaft) under the conditions of a silicon roll hardness of 75 to 85°, a silicon roll surface temperature of 190 to 230°C, a shaft rotation speed of 15 to 25 rpm, and a pressure of 15 to 25 kgf / cm 2 Then, the object to which the transfer layer is transferred is heated at 100°C for 90 minutes. The object decorated with the transfer layer is evaluated as described below.

[0132] <Resistance to solvents test>

[0133] The position of the object to which the transfer layer is attached is rubbed 6 times with a cloth impregnated with a solvent (ethyl acetate), and the state of the transfer layer at this time is evaluated according to the following criteria, and the results are shown in Table 1.

[0134] A: No dissolution is observed in the transfer layer

[0135] B: Dissolution is observed in the transfer layer

[0136] <Resistance to abrasion test>

[0137] A load of 1250 g is applied to the position of the object to which the transfer layer is attached with an interval of 150 mm, and the rubbing is continued at an interval of 1 round trip per second, and the evaluation is performed according to the following criteria, and the results are shown in Table 1.

[0138] A: The surface of the shaft is not exposed even after 75 or more rubs

[0139] B: The surface of the shaft is exposed before 75 rubs

[0140] <Confirmation of foil cracking>

[0141] The transfer layer attached to the object is confirmed by visual observation, and the evaluation is performed according to the following criteria, and the results are shown in Table 1.

[0142] A: No defects are observed in the transfer layer

[0143] B: Defects are observed in the transfer layer

[0144]

[0145] (SUMMARY)

[0146] According to the above-described embodiments, the present disclosure includes the following modes. In the following, the symbols are annotated in parentheses only for the sake of clearly presenting the correspondence with the embodiments.

[0147] The thermal transfer foil (100) of the first mode of the present disclosure has a base material (4) and a transfer layer (10) disposed on the base material (4). The transfer layer (10) has a peeling layer (1), a color layer (2), and an adhesive layer (3) sequentially stacked in this order close to the base material (4). The peeling layer (1) contains an isocyanate compound (A) and a polyol compound (B) having thermoplasticity. The isocyanate compound (A) contains a first isocyanate compound (A1) and a second isocyanate compound (A2) that are different from each other. The first isocyanate compound (A1) does not have an isocyanate group blocked by a blocking agent. The second isocyanate compound (A2) has an isocyanate group blocked by a blocking agent.

[0148] According to this mode, it is possible to provide a thermal transfer foil (100) that can ensure the solvent resistance and the wear resistance of the transfer layer (10) attached to the object (20).

[0149] The thermal transfer foil (100) of the second mode of the present disclosure is based on the thermal transfer foil (100) of the first mode. The first isocyanate compound (A1) contains at least one of hexamethylene diisocyanate and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate.

[0150] According to this mode, it is possible to further improve the wear resistance of the peeling layer (1).

[0151] The thermal transfer foil (100) of the third mode of the present disclosure is based on the thermal transfer foil (100) of the first or second mode. The first isocyanate compound (A1) contains a polyisocyanate resin.

[0152] According to this mode, it is possible to further improve the wear resistance of the peeling layer (1).

[0153] The thermal transfer foil (100) of the fourth mode of the present disclosure is based on the thermal transfer foil (100) of any one of the first to third modes. The temperature at which the blocking agent dissociates from the second isocyanate compound (A2) is 100°C to 120°C.

[0154] According to this aspect, by making the temperature at which the blocking agent departs from the first isocyanate compound (A1) 90°C or higher, the release layer (1) can be prevented from being excessively cured until the transfer layer (10) is attached to the object (20). Thus, the transferability of the thermal transfer foil (100) can be sufficiently ensured. In addition, by making the temperature at which the blocking agent departs from the first isocyanate compound (A1) 120°C or lower, the release layer (1) can be cured by heating at a temperature that does not impair the quality of the object (20).

[0155] The thermal transfer foil (100) of the fifth aspect of the present disclosure is based on the thermal transfer foil (100) of any one of the first to fourth aspects. The color layer (2) contains an isocyanate compound (E) and a polyol compound (F).

[0156] According to this aspect, the solvent resistance and the abrasion resistance of the color layer (2) can be improved.

[0157] The thermal transfer foil (100) of the sixth aspect of the present disclosure is based on the thermal transfer foil (100) of the fifth aspect. The isocyanate compound (E) does not contain an isocyanate compound (E1) that does not have an isocyanate group blocked by a blocking agent.

[0158] According to this aspect, the color layer (2) can be formed on the release layer (1) without being cured. Thus, the transferability of the thermal transfer foil (100) can be prevented from being impaired.

[0159] The thermal transfer foil (100) of the seventh aspect of the present disclosure is based on the thermal transfer foil (100) of the fifth or sixth aspect. The isocyanate compound (E) contains an isocyanate compound (E2) that has an isocyanate group blocked by a blocking agent.

[0160] According to this aspect, after the transfer layer (10) is attached to the object (20), the color layer (2) can be cured by heating the transfer layer (10). Thus, the transferability of the thermal transfer foil (100) can be sufficiently ensured, and the solvent resistance and the abrasion resistance of the color layer (2) can be improved.

[0161] The thermal transfer foil (100) of the eighth aspect of the present disclosure is based on the thermal transfer foil (100) of any one of the first to seventh aspects. The adhesive layer (3) contains an isocyanate compound (G) and a polyol compound (H).

[0162] According to this aspect, the solvent resistance and the abrasion resistance of the adhesive layer (3) can be improved.

[0163] The thermal transfer foil (100) of the 9th aspect of the present disclosure is based on the thermal transfer foil (100) of the 8th aspect. The isocyanate compound (G) does not contain an isocyanate compound (G1) that does not have an isocyanate group blocked with a blocking agent.

[0164] According to this aspect, in this case, the adhesive layer (3) can be formed on the release layer (1) without being cured. Thus, the adhesion of the adhesive layer (3) to the object (20) can be further ensured.

[0165] The thermal transfer foil (100) of the 10th aspect of the present disclosure is based on the thermal transfer foil (100) of the 8th or 9th aspect. The isocyanate compound (G) contains an isocyanate compound (G2) having an isocyanate group blocked with a blocking agent.

[0166] According to this aspect, after the transfer layer (10) is attached to the object (20), the adhesive layer (3) can be cured by heating the transfer layer (10). Thus, the adhesion of the adhesive layer (3) to the object (20) can be ensured and the solvent resistance and wear resistance of the adhesive layer (3) can be improved.

[0167] The thermal transfer foil (100) of the 11th aspect of the present disclosure contains, in any one of the 1st to 10th aspects, a polyol compound (B) that is a chlorovinyl-vinyl acetate copolymer-based polyol.

[0168] Explanation of Symbols

[0169] 1 Release Layer

[0170] 2 Color Layer

[0171] 3 Adhesive Layer

[0172] 4 Substrate

[0173] 10 Transfer Layer

[0174] 20 Object

[0175] 100 Thermal Transfer Foil

Claims

1. A heat transfer foil comprising a substrate and a transfer layer disposed on said substrate, The transfer layer comprises a release layer, a color layer, and an adhesive layer stacked sequentially in order adjacent to the substrate. The release layer contains an isocyanate compound (A) and a thermoplastic polyol compound (B). The isocyanate compound (A) contains two distinct isocyanate compounds, a first isocyanate compound (A1) and a second isocyanate compound (A2). The first isocyanate compound (A1) does not have an isocyanate group that is capped by the capping agent. The second isocyanate compound (A2) has isocyanate groups capped by a capping agent.

2. The heat transfer foil according to claim 1, wherein, The first isocyanate compound (A1) contains at least one of hexamethylene diisocyanate and 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate.

3. The heat transfer foil according to claim 1 or 2, wherein, The first isocyanate compound (A1) contains a polyisocyanate resin.

4. The heat transfer foil according to claim 1, wherein, The capping agent is released from the second isocyanate compound (A2) at a temperature of 100°C to 120°C.

5. The heat transfer foil according to claim 1, wherein, The color layer contains isocyanate compound (E) and polyol compound (F).

6. The heat transfer foil according to claim 5, wherein, The isocyanate compound (E) contains an isocyanate compound (E2) having isocyanate groups capped by a capping agent.

7. The heat transfer foil according to claim 1, wherein, The adhesive layer contains an isocyanate compound (G) and a polyol compound (H).

8. The heat transfer foil according to claim 7, wherein, The isocyanate compound (G) contains an isocyanate compound (G2) having isocyanate groups capped by a capping agent.

9. The heat transfer foil according to claim 1, wherein, The polyol compound (B) contains a vinyl chloride-vinyl acetate copolymer polyol.

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