Decorative transfer film and transfer decorating method

Abstract

To provide a decorative transfer film by which a decorative layer can be applied with high printability, and transfer can be performed onto an article to be decorated by using the transfer film with high transferability and adhesion.SOLUTION: An ultraviolet curable ink for printing a decorative layer on a carrier film includes 85 wt.% or more of photopolymerizable monomers based on the weight of the entire ultraviolet curable ink composition, the photopolymerizable monomers consist of polyfunctional monomers and monofunctional monomers, the polyfunctional monomers are included in the ratio of 55 to 70 wt.% based on the entire photopolymerizable monomers, and the polyfunctional monomers include 50 wt.% or more of trifunctional or higher monomers based on the total weight of the polyfunctional monomers, and the decorative layer is semi-cured.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a decorative transfer film that is used to decorate an article by transferring it onto the surface of the article, and a transfer decoration method for decorating an article using this decorative transfer film. [Background technology]

[0002] 2. Description of the Related Art Various decorating techniques have been developed for decorating an article by transferring a decorative layer of a decorative transfer film onto the surface of the article.

[0003] One decoration technique is a water pressure transfer method in which a transfer film having a decorative layer (printed pattern layer) printed and dried on a water-soluble carrier film is floated in water with the decorative layer facing up, and the item to be decorated is pushed into the water while in contact with the transfer film, thereby transferring the decorative layer to the surface of the item.

[0004] This hydraulic transfer method has the drawback of being difficult to use because it is difficult to press the item into the desired position on the decorative layer, resulting in poor decorative reproducibility. In addition, the dried decorative layer must be dissolved to reproduce the adhesiveness, which requires applying a solvent to the decorative layer, resulting in poor workability.

[0005] Another decoration technique involves placing a decorative transfer film with the decorative layer facing downwards at the boundary between a lower chamber containing the item to be decorated and an upper chamber, heating the decorative layer of the transfer film to soften it, and then bringing the item into contact with the transfer film while utilizing the pressure difference between the upper and lower chambers to pressurize the decorative layer of the transfer film into contact with the item, thereby transferring the decorative layer to the surface of the item (see Patent Documents 1 to 3).

[0006] Of these, in the decoration technology of Patent Document 1 (Patent Publication No. 5599009), the decorative layer consists of three layers: an ultraviolet-curable clear layer, a pattern layer, and an adhesive layer. The ultraviolet-curable clear layer provides chemical and physical protective functions such as corrosion resistance and abrasion resistance, but the layer providing the protective function and the adhesive layer are required separately, which has the disadvantage of making the transfer film structure complex.

[0007] Furthermore, in the decoration technology of Patent Document 2 (JP 2017-144676 A), the decorative layer is composed of a printing layer made of an ultraviolet-curable paint applied to a transfer sheet. The transfer sheet having this printing layer is pressed against the surface of an article in a vacuum chamber to transfer the printing layer, and this transfer is achieved by ensuring that the affinity between the printing layer and the surface of the article is higher than the affinity between the printing layer and the transfer sheet. It is disclosed that preferably, an adhesive layer is provided on the printing layer to further improve transfer to the surface of the article. However, transfer due to differences in affinity has the disadvantages of unstable transfer of the printing layer, and providing an adhesive layer complicates the structure of the transfer film.

[0008] Furthermore, in the decoration technology of the third patent document (JP 2020-001259 A), the decorative layer of the transfer film contains an ultraviolet-curing resin, and this decorative layer is fused to the article by heating both the transfer film and the article to be decorated while applying pressure to the decorative layer, and the decorative layer is irradiated with ultraviolet light after the carrier film holding the decorative layer is peeled off from the decorative layer. However, there are drawbacks in that the device for heating both the transfer film and the article to be decorated is complicated, and if ultraviolet light is irradiated after peeling off the carrier film, the decorative layer is exposed to air, which causes the decorative layer to oxidize before UV curing, resulting in undesirable changes to the decorative layer.

[0009] Several UV-curable inks are known that are used in the field of inkjet technology, not in the field of decoration technology, and have weather resistance that can also be used for printing printed layers of transfer films in decoration technology (see Patent Documents 4 to 6). All of these patent documents aim to improve weather resistance, and in particular, Patent Document 6 (JP 2022-184084 A) discloses an ink composition that can be printed on a substrate with excellent curability and adhesion.

[0010] However, even if the ink compositions disclosed in these patent documents are used directly in the decorative layer of a decorative transfer film, it is difficult to achieve high adhesion during transfer. Furthermore, although the transfer film contains a carrier film, the ink compositions of Patent Documents 4 to 6 are difficult to peel from the carrier film, and therefore the ink compositions of these conventional technologies cannot be used directly in printing the decorative layer of a decorative transfer film. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent No. 5599009 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-144676 [Patent Document 3] Japanese Patent Application Publication No. 2020-001259 [Patent Document 4] Japanese Patent Application Laid-Open No. 2008-080629 [Patent Document 5] Japanese Patent Application Laid-Open No. 2017-125133 [Patent Document 6] Japanese Patent Publication No. 2022-184084 Summary of the Invention [Problem to be solved by the invention]

[0012] The first problem to be solved by the present invention is to provide a decorative transfer film that can be transferred in a simple process and cured by ultraviolet light while maintaining the chemical and physical functions of the decorative layer and maintaining high adhesion to the item to be decorated.

[0013] The second problem to be solved by the present invention is to provide a transfer decoration method that can transfer the decorative layer to the article to be decorated in a simple process and harden it with ultraviolet light while maintaining the chemical and physical functions of the decorative layer and maintaining high adhesion to the article to be decorated. [Means for solving the problem]

[0014] The means for solving the first problem of the present invention is to provide a decorative transfer film comprising a light-transmitting carrier film and a decorative layer printed on the carrier film with ultraviolet-curable ink, wherein the ultraviolet-curable ink of the decorative layer contains 85% or more by weight of photopolymerizable monomers relative to the total weight of the ultraviolet-curable ink, the photopolymerizable monomers are composed of polyfunctional monomers and monofunctional monomers, the polyfunctional monomers are contained in a proportion of 55 to 70% by weight relative to the total weight of the photopolymerizable monomers, and the polyfunctional monomers contain 50% or more by weight of trifunctional or higher functional monomers relative to the total weight of the polyfunctional monomers, and the decorative layer of ultraviolet-curable ink is semi-cured.

[0015] In the first means for solving the problems of the present invention, it is preferable that the ultraviolet-curable resin composition constituting the ultraviolet-curable ink does not contain a functional oligomer.

[0016] In the first means for solving the problem of the present invention, the ultraviolet curable ink of the decorative layer may contain an ultraviolet absorber.

[0017] In the first means for solving the problem of the present invention, it is preferable to have a light-transmitting functional layer between the carrier film and the decorative layer. This light-transmitting functional layer can be, for example, a color clear layer and / or a photocatalytic functional layer such as an anti-fouling layer.

[0018] In the first means for solving the problem of the present invention, an auxiliary adhesive layer may be laminated on the decorative layer on the side opposite to the carrier film.

[0019] The second means for solving the problem of the present invention is a process of preparing a decorative transfer film having a decorative layer formed by printing ultraviolet-curable ink on a light-transmitting carrier film and semi-curing it by irradiating ultraviolet rays; a process of transferring the semi-cured decorative layer of the decorative transfer film to the surface of an article to be decorated by a pressure transfer means; a process of irradiating ultraviolet rays through the light-transmitting carrier film of the decorative transfer film having the semi-cured decorative layer thus transferred to fully cure the semi-cured decorative layer to form a finished decorative layer; and a process of transferring the semi-cured decorative layer of the decorative transfer film having the semi-cured decorative layer thus transferred to the surface of an article to be decorated by a pressure transfer means. The object of the present invention is to provide a transfer decoration method comprising a step of peeling and removing a photopolymerizable monomer from a finished decorative layer, wherein the ultraviolet curable ink used to print the decorative layer contains 85% by weight or more of a photopolymerizable monomer relative to the total weight of the ultraviolet curable ink, the photopolymerizable monomer being composed of a polyfunctional monomer and a monofunctional monomer, the polyfunctional monomer being contained in a proportion of 55 to 70% by weight relative to the total weight of the photopolymerizable monomer, and the polyfunctional monomer containing 50% by weight or more of a trifunctional or higher functional monomer relative to the total weight of the polyfunctional monomer.

[0020] In the second means for solving the problems of the present invention, the ultraviolet curable ink preferably does not contain a functional oligomer.

[0021] In the second means for solving the problems of the present invention, the ultraviolet curable ink may contain an ultraviolet absorber.

[0022] In the second means for solving the problem of the present invention, the ultraviolet irradiation conditions when semi-curing the decorative layer are an irradiation intensity of 1 to 100 mW / cm 2 The range is 1 to 200 mJ / cm 2 It is preferable that the range is:

[0023] In the second means for solving the problem of the present invention, the pressure transfer means for transferring the decorative layer can be configured to pressurize and transfer the decorative layer onto the surface of the article by utilizing the differential pressure between the top and bottom of the decorative transfer film while the decorative transfer film and the article to be decorated are in contact with each other. [Effects of the Invention]

[0024] According to the present invention, the decorative layer is formed by printing ultraviolet-curable ink, so that the chemical and physical functions of the decorative layer can be maintained. However, this decorative layer is adhered to the surface of the article using its inherent high adhesiveness due to the semi-curing of the ultraviolet-curable ink with a specific composition, so that the decorative layer can be stably adhered to the article with high strength without the need for a special adhesive layer. Furthermore, the decorative layer can be fully cured after transfer by irradiating it with ultraviolet light through a light-transmitting carrier film, so the process is simple and simplified, allowing for highly efficient work. This full curing also has the advantage of allowing the decorative layer to be adhered to the surface of the article with high adhesion. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic diagram illustrating a process for producing the decorative transfer film of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a state before transfer by the transfer decoration method of the present invention. [Figure 3] 1 is a schematic cross-sectional view showing a state during transfer in the transfer decoration method of the present invention. [Figure 4] 2 is a schematic diagram showing a main curing step of the transfer decoration method of the present invention. FIG. [Figure 5] 1 is a schematic cross-sectional view of a decorated article obtained by the transfer decoration method of the present invention and a carrier film peeled off from the decorated article. DETAILED DESCRIPTION OF THE INVENTION

[0026] The decorative transfer film of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 shows the manufacturing process of a decorative transfer film 10. This decorative transfer film 10 comprises a carrier film 12 and a decorative layer 14 of ultraviolet-curable ink formed on this carrier film 12.

[0027] The carrier film 12 is made of a light-transmitting thermoplastic resin (e.g., non-stretchable polyester resin) with an ink-releasable surface. This carrier film 12 can be, for example, a film manufactured by Okura Kogyo Co., Ltd. This carrier film has a thickness of, for example, about 0.02 to 0.3 mm.

[0028] 1(a), the decorative layer 14 is formed by printing a predetermined pattern on the carrier film 12 with ultraviolet-curable ink by spraying it from the nozzles of an inkjet head 16. The printing method for the ultraviolet-curable ink can be inkjet printing or any other known printing method such as gravure printing, screen printing, flexographic printing, or offset printing.

[0029] The UV-curable ink contains 85% by weight or more of photopolymerizable monomers based on the total weight of the UV-curable ink, and the photopolymerizable monomers consist of polyfunctional monomers and monofunctional monomers. Each of these will be explained in detail below.

[0030] (polyfunctional monomer) The polyfunctional monomer is a component that contributes to the adhesiveness of the UV-curable ink when semi-cured, and to the physical properties of the decorative layer, which is the cured product of the UV-curable ink, such as mechanical strength, chemical resistance, and adhesion. The polyfunctional monomer is contained in a proportion of 55 to 70 wt% of the total photopolymerizable monomers. If the content of the polyfunctional monomer relative to the total photopolymerizable monomers is less than 55 wt%, the adhesiveness of the UV-curable ink when semi-cured and the physical properties of the decorative layer, such as mechanical strength, chemical resistance, and adhesion, will be insufficient. If the content of the polyfunctional monomer relative to the total photopolymerizable monomers is greater than 70 wt%, the viscosity of the UV-curable ink will be too high, making printing difficult, and the ejection performance will be significantly reduced, especially in inkjet printing. The UV-curable ink used in the present invention preferably does not contain a functional oligomer, because functional oligomers increase the viscosity of the ink and reduce the ejection performance of the inkjet printer.

[0031] (Tri- or higher functional monomers among multifunctional monomers) The polyfunctional monomer is required to contain 50% by weight or more of trifunctional or higher polyfunctional monomers relative to the total weight of the polyfunctional monomers. This trifunctional or higher polyfunctional monomer is a major component that contributes to the mechanical strength and chemical resistance of the decorative layer obtained by curing after transfer. If the content of trifunctional or higher polyfunctional monomers relative to the total weight of the polyfunctional monomers is less than 50% by weight, the physical properties of the decorative layer, such as mechanical strength and chemical resistance, may be insufficient. Furthermore, the greater the number of functional groups in the trifunctional or higher polyfunctional monomer, the better the physical properties required of the decorative layer. However, this increases the viscosity of the UV-curable ink when uncured. Therefore, it is preferable to combine trifunctional and tetrafunctional or higher monomers within the above content range to achieve a formulation that adjusts the balance between the physical properties of the decorative layer and the viscosity of the UV-curable ink when uncured. Examples of tri- or higher functional monomers include photopolymerizable monomers with four or more functional groups, such as dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxytetraacrylate, and ditrimethylolpropane tetraacrylate, as well as trifunctional monomers, such as trimethylolpropane triacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, and glyceryl triacrylate.

[0032] (Difunctional monomers in multifunctional monomers) The polyfunctional monomer may contain a bifunctional monomer to facilitate adjustment of the balance between the physical properties of the decorative layer and the viscosity of the uncured UV-curable ink. After curing, the bifunctional monomer is incorporated into a crosslinked structure, contributing to the mechanical strength of the decorative layer, but to a lesser extent than trifunctional or higher functional monomers. On the other hand, the bifunctional monomer can adjust the viscosity of the uncured UV-curable ink lower than trifunctional or higher functional monomers. Therefore, by blending it in combination with a trifunctional or higher functional monomer, it is possible to adjust the balance between the physical properties of the decorative layer and the viscosity of the uncured UV-curable ink. The bifunctional monomer is preferably 50% by weight or less of the total weight of the polyfunctional monomers. If the blending ratio of the bifunctional monomer exceeds 50% by weight of the total weight of the polyfunctional monomers, the strength of the cured decorative layer may decrease. Examples of bifunctional monomers include hydroxypivalic acid neopentyl glycol diacrylate, polytetramethylene glycol diacrylate, trimethylolpropane acrylic acid benzoate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol (200) diacrylate, polyethylene glycol (400) diacrylate, polyethylene glycol (600) diacrylate, neopentyl glycol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, dimethylol-tricyclodecane diacrylate, and bisphenol A diacrylate.

[0033] (monofunctional monomer) The monofunctional monomer is a component for adjusting the viscosity of the uncured UV-curable ink to a level suitable for printing, and this monofunctional monomer is crosslinked with the polyfunctional monomer after curing. Examples of the monofunctional monomer include caprolactone acrylate, tridecyl acrylate, isodecyl acrylate, isooctyl acrylate, isomyristyl acrylate, isostearyl acrylate, 2-ethylhexyl-diglycol diacrylate, 2-hydroxybutyl acrylate, 2-acryloyloxyethyl hexahydrophthalic acid, neopentyl glycol acrylic acid benzoate, isoamyl acrylate, lauryl acrylate, stearyl acrylate, butoxyethyl acrylate, ethoxy-diethylene glycol acrylate, and methoxy-triethylene glycol acrylate. Acrylate, methoxy-polyethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxy-polyethylene glycol acrylate, nonylphenol acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl-succinate, 2-acryloyloxyethyl-phthalate, 2-acryloyloxyethyl-2-hydroxyethyl-phthalate, etc.

[0034] (Photopolymerization initiator) The UV-curable ink contains a photopolymerization initiator to initiate the photopolymerization reaction of the photopolymerizable monomer, and any known photopolymerization initiator can be selected and used. Photopolymerization initiators are classified into surface-curing photopolymerization initiators and internal-curing photopolymerization initiators, and it is preferable to contain both. For example, hydroxyketone-based initiators can be used as the surface-curing photopolymerization initiator, and for example, acylphosphine oxide-based initiators can be used as the internal-curing photopolymerization initiator. The addition ratio of the photopolymerization initiator to the photopolymerizable monomer is 1% to 50% by weight, more preferably 3% to 30% by weight, and particularly preferably 5% to 10% by weight.

[0035] (ultraviolet absorber) The ultraviolet-curable ink for printing a pattern on the decorative layer may contain an ultraviolet absorber. This ultraviolet absorber converts ultraviolet light absorbed by the transferred decorative layer into small amounts of heat energy, protecting the transferred decorative layer and preventing deterioration of the transferred decorative layer due to ultraviolet light. Examples of ultraviolet absorbers include benzotriazole-based compounds, benzophenone-based compounds, cinnamic acid-based compounds, and triazine-based compounds. The content of the ultraviolet absorber is preferably 1 to 6% by weight of the total ink.

[0036] (polymerization inhibitor) The UV-curable ink may contain a polymerization inhibitor. This polymerization inhibitor reacts with radicals generated from the photopolymerization initiator of the UV-curable ink, converting them into a stable substance. This inhibits polymerization during storage and prevents undesired polymerization due to external light, heat, or other factors. Examples of suitable polymerization inhibitors include hindered phenol compounds, phenol compounds, hydroquinone compounds, phenothiazine compounds, phosphorus compounds, and nitrosophenylhydroxylamine compounds. Specific examples include 4-methoxyphenol, tert-butylhydroquinone, 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], hydroquinone, methylhydroquinone, phenothiazine, dicumylphenothiazine, triphenylphosphine, and aluminum salt of N-nitrosophenylhydroxylamine. The content of the polymerization inhibitor is preferably 0.01 to 2% by mass, and more preferably 0.1 to 1% by mass, based on the total amount of the ink.

[0037] (Other ingredients 1 = pigments) The UV-curable ink may contain a coloring pigment, if necessary. The pigment is not particularly limited, and may be any of various known organic or inorganic pigments. Examples of organic pigments include dye lake pigments, azo-based, benzimidazolone-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigo-based, thioindigo-based, perylene-based, perinone-based, diketopyrrolopyrrole-based, isoindolinone-based, nitro-based, nitroso-based, anthraquinone-based, flavanthrone-based, quinophthalone-based, pyranthrone-based, and indanthrone-based pigments. Examples of inorganic pigments include colored pigments (including achromatic coloring pigments such as white and black) such as titanium oxide, red iron oxide, antimony red, cadmium yellow, cobalt blue, ultramarine blue, Prussian blue, iron black, chromium oxide green, carbon black, and graphite, as well as extender pigments such as calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, and talc. The pigment content is not particularly limited. For example, other than the white pigment, the content is preferably 0.5% by mass or more, more preferably 1% by mass or more, of the total UV-curable ink, with the upper limit being preferably 10% by mass or less, more preferably 7% by mass or less. On the other hand, the content of the white pigment is preferably 8% by mass or more, more preferably 10% by mass or more, of the total UV-curable ink, with the upper limit being preferably 18% by mass or less, more preferably 15% by mass or less. When the pigment content is within the above range, the UV-curable ink can have a moderate coloring power while minimizing the effect on the physical properties of the cured decorative layer.

[0038] (Other ingredients 2 = dispersant) When the UV-curable ink contains a pigment, it is preferable that the ink further contains a dispersant to improve pigment dispersibility. The dispersant is not particularly limited, but a dispersant commonly used in preparing pigment dispersions is preferable. Specific examples of dispersants include those containing one or more of the following as the main component: polyoxyalkylene polyalkylene polyamines, vinyl polymers and copolymers, acrylic polymers and copolymers, polyesters, polyamides, polyimides, polyurethanes, amino polymers, silicon-containing polymers, sulfur-containing polymers, fluorine-containing polymers, and epoxy resins. Commercially available polymer dispersants include the Discol® series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., the Solsperse® series (e.g., Solsperse 6000) manufactured by Lubrizol Corporation, and the Disperbyk series manufactured by BYK Chemie.

[0039] The ultraviolet-curable ink can be obtained by dispersing and mixing the above-mentioned components using a dispersing machine such as a wet circulation mill, a bead mill, a ball mill, a sand mill, an attritor, a roll mill, a DCP mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a high-pressure homogenizer (such as a Microfluidizer, Nanomizer, Ultimizer, Genus PY, or DeBEE2000), or a pearl mill.

[0040] The decorative transfer film 10 of the present invention is sent to the semi-curing process shown in Figure 1(b), where the decorative layer 14 printed on the carrier film 12 is semi-cured by irradiating it with ultraviolet light UV1 from a light source lamp 18H such as a high-pressure mercury lamp, metal halide lamp, or UVLED (Ultraviolet Light Emitting Diode) to form a semi-cured decorative layer 14P. This is done to impart some hardness to the pattern of the decorative layer 14 to prevent it from becoming distorted between storage and the transfer operation, and to maintain adequate adhesion to the object during transfer. The degree of semi-curing is sufficient as long as it is adhesive enough to prevent the pattern of the decorative layer 14 from becoming distorted between storage and the transfer operation, and can be adjusted depending on the properties of the UV-curable ink, such as its viscosity. Furthermore, the degree of curing of the semi-cured decorative layer 14P is greater on the carrier film 12 side than on the side opposite the carrier film 12 (hereinafter referred to as the "surface side"). Therefore, the degree of curing of the surface side of the decorative layer 14P is less than that of the carrier film side. In this way, if the degree of curing of the surface side of the decorative layer 14P is less than that of the carrier film side, the adhesiveness required for adhesion to the object to be decorated can be maintained. Furthermore, if the degree of curing of the carrier film side of the decorative layer 14P is greater than that of the surface side, the surface of the decorative layer will have a cured film when transferred to the object. This prevents the penetration of oxygen, which may penetrate the carrier film 12 and inhibit the curing of the decorative layer during full curing. Therefore, the entire decorative layer can be effectively cured in a low-oxygen environment. To achieve this semi-cured decorative layer 14, it is preferable to semi-cure the decorative layer 14 in an atmosphere with an oxygen concentration similar to that of atmospheric air. The ultraviolet irradiation conditions for semi-curing the decorative layer 14 are an irradiation intensity of 1 to 100 mW / cm. 2 The range is 1 to 200 mJ / cm 2It is preferable that the range is . If at least one of the irradiation intensity and the integrated light amount is below the lower limit, the curing reaction of the ultraviolet-curable ink is difficult to proceed and the viscosity is difficult to increase, which may result in an inability to prevent the pattern of the decorative layer 14 from becoming distorted between storage and the transfer operation. Furthermore, if at least one of the irradiation intensity and the integrated light amount exceeds the upper limit, the curing reaction of the ultraviolet-curable ink proceeds too quickly, reducing the adhesiveness of the surface of the decorative layer 14, which may result in insufficient adhesion when transferred to the item to be decorated.

[0041] The decorative transfer film 10 of the present invention may have a light-transmitting functional layer (not shown) between the carrier film 12 and the decorative layer 14. Examples of this light-transmitting functional layer include a color clear layer and an anti-fouling functional layer containing a photocatalyst. The light-transmitting functional layer is peelably laminated on the carrier film 12, and the decorative layer 14 is formed of ultraviolet-curable ink on the surface of the light-transmitting functional layer opposite the carrier film 12.

[0042] Next, a transfer method for decorating an article using the decorative transfer film of the present invention will be described in detail with reference to FIG. 2 and subsequent drawings.

[0043] First, referring to Figure 2, the pressure transfer means 20 is shown, and this pressure transfer means 20 comprises upper and lower chambers 22U and 22L, a heating means HT provided in the upper chamber 22U, a pressure means (gas cylinder) GS connected to the upper chamber 22U, an air intake means (vacuum pump) VP connected to the air intake port 24 of the lower chamber 22L, and an article support means 26 placed on the floor of the lower chamber 22L to support the article 30 to be decorated.

[0044] (Preparation before transcription) The article 30 to be decorated is fixed and stored in the article support means 26 of the lower chamber 22L, as shown in Fig. 2, and the decorative transfer film 10 having the semi-cured decorative layer 14P shown in Fig. 1 is placed between the upper and lower chambers 22U, 22L with the decorative layer 14P facing downward, and the upper and lower chambers 22U, 22L are closed and sealed in this state. In the illustrated embodiment, the article 30 is shown to be an article with an arc-shaped cross section, and this article is supported by the elevating stage 26S of the article support means 26.

[0045] (heating of transfer film for decoration) Next, the heating means HT provided in the upper chamber 22U is operated to heat the decorative transfer film 10 and soften the carrier film 12. Therefore, the softening of the carrier film 12 makes it easier to adhere the decorative layer 14 to the three-dimensional surface of the article to be decorated, as will be described later.

[0046] (Decorative layer transfer) Then, as shown in FIG. 3 , the liftable stage 26S is raised to press the article 30 against the semi-cured decorative layer 14P of the decorative transfer film 10. The lower chamber 22L is evacuated by operating the air intake means VP connected to the air intake port 24 of the lower chamber 22L. Meanwhile, gas is injected into the upper chamber 22U from the gas cylinder GB, which serves as a pressurizing means. This operation creates a pressure difference between the upper and lower chambers 22U and 22L, causing the decorative transfer film 10 to adhere to the surface of the article 30 to be decorated. As previously mentioned, the transfer film 10 is softened by heating, and is stretched and deformed to conform to the surface of the article 30 due to the pressure difference between the upper and lower chambers. As previously mentioned, the decorative layer 14 is printed using ink containing a predetermined proportion of polyfunctional monomers relative to monofunctional monomers. This ink therefore has an appropriate viscosity and maintains high adhesion. Therefore, the semi-cured decorative layer 14P is well adhered and transferred to the surface of the article 30 to be decorated. After the decorative layer 14P is transferred, the suction of the suction means VP is stopped, the pressurizing means GS is released, the upper and lower chambers 22U and 22L are opened, and the article 30 onto which the decorative layer 14P has been transferred is removed from the chambers.

[0047] (Main curing of decorated items) 4, ultraviolet rays UV2 are irradiated from the light source lamp 18H onto the semi-cured decorative layer 14P through the light-transmitting carrier film 12 of the transfer film 10 transferred onto the article 30, to fully cure the decorative layer 14P. This full curing is performed under ultraviolet irradiation conditions that correspond to the curing properties of the ultraviolet-curable ink that constitutes the decorative layer 14, specifically, 50 to 400 mW / cm. 2 UV intensity of 3000 to 6000 mJ / cm 2 It is preferable to carry out the process until

[0048] (Removing the carrier film from the decorative transfer film) 5, the remaining transfer film portion 10R of the carrier film 12 and the remaining decorative layer 14B that was not transferred to the article 30 is peeled off from the article 30, and the decorated article 30D decorated with the transferred decorative layer 14D is collected. Note that, in order to leave the decorative layer 14D on the article 30 when the carrier film 12 is released, the degree of adhesion of the decorative layer 14 to the carrier film 12 is set lower than the degree of adhesion to the article 30.

[0049] In the above embodiment, the ultraviolet-curable ink used in the present invention is semi-cured and fully cured by ultraviolet light. However, the ink may be semi-cured and fully cured by active energy rays such as electron beams, and different radiation sources may be used for the semi-curing step and the fully curing step.

[0050] Note that Figure 2 shows an embodiment using a three-dimensional surface decoration method (Three Dimension Overlay Method, TOM) using a heating and vacuum pressure method as the pressure transfer means, but other heating and vacuum pressure methods such as the NATS method (Navitas) or the new TFH method (Asano Laboratory), as well as other known methods such as heating and vacuum forming and in-mold transfer methods may also be used. [Example]

[0051] The present invention will be described in more detail below with reference to examples, but is not limited to these examples. The decorative transfer film, transfer decoration method, and evaluation method of the decorated product in the following examples and comparative examples are as follows (1) to (3).

[0052] (1) Transferability The decorative transfer film was transferred to the surface of an article, and the condition of the decorative layer laminated on the article was observed. If the carrier film could be peeled off and no decorative layer remained on the film, it was judged as "good" (○), and if the carrier film could not be peeled off and no decorative layer remained on the carrier film, it was judged as "poor" (×).

[0053] (2) Adhesion The decorative layer (transfer layer) of the decorated article obtained in each Example and Comparative Example was cut in a grid pattern at 1 mm intervals to form 100 squares with sides of 1 mm, and then the area with the squares was observed for peeling using Cellotape (registered trademark) (manufactured by Nichiban) in a cross-cut test (based on the old JIS K5400-8.5) to evaluate adhesion. In this case, if no squares of the decorative layer (transfer layer) peeled off after the cross-cut test, it was evaluated as "good" (indicated by "◎"), if some of the squares peeled off, it was evaluated as "fair" (indicated by "○"), and if one or more squares peeled off, it was evaluated as "poor" (indicated by "×").

[0054] (3) Mechanical strength of the decorative layer after hardening "Mechanical strength of film" was evaluated by measuring the strength of the film (decorative layer) of the tested article using a pencil hardness test (based on JIS K5600-5-4), with "H or higher" being rated as "◎", "HB to F" being rated as "○", and "HB not achieved" being rated as "×".

[0055] Table 1 shows the specifications of each component of the ultraviolet curable ink used in the following examples and comparative examples.

[0056] [Table 1]

[0057] Example 1 The ultraviolet curable ink was prepared by adding the following components (A) to (G) to a high-speed mixer and mixing them. (A) 86.0 parts by weight of a photopolymerizable monomer consisting of the following components (a1) to (a5): (a1) 8.7 parts by weight of a mixed pentafunctional and hexafunctional monomer Ethoxylated dipentaerythritol polyacrylate (NK Ester A-DPH-12E, manufactured by Shin-Nakamura Chemical Co., Ltd.) (a2) Trifunctional monomer 28.9 parts by weight Trimethylolpropane trimethacrylate (Light Ester TMP (Light Ester is a registered trademark) manufactured by Kyoeisha Chemical Co., Ltd.) (a3) Bifunctional monomer No. 1 7.7 parts by weight 1,6-Hexanediol diacrylate (HDDA manufactured by Daicel Allnex) (a4) Bifunctional monomer No. 2 2.0 parts by weight Dipropylene glycol diacrylate (DPGDA, manufactured by Daicel Allnex) (a5) Monofunctional monomer 38.7 parts by weight Tetrahydrofurfuryl acrylate (VISCOAT#150 (VISCOAT is a registered trademark) manufactured by Osaka Organic Chemical Industry Co., Ltd.) (B) 5.5 parts by weight of the following polymerization initiator: 2-Hydroxy-2-methyl-1-phenyl-1-propanone (Omnirad 1173 (Omnirad is a registered trademark) manufactured by IGM Resins BV) (C) 2.9 parts by weight of the following ultraviolet absorber 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (Tinuvin 928 (Tinuvin is a registered trademark) manufactured by BASF Japan Ltd.) (D) 2.5 parts by weight of the following light stabilizer: 2,2,6,6-tetramethyl-1-[2-[(3,5,5-trimethyl-1-oxohexyl)oxy]ethyl]-4-piperidinyl 3,5,5-trimethylhexanoate (Tinuvin 249 (Tinuvin is a registered trademark) manufactured by BASF Japan Ltd.) (E) 0.1 parts by weight of the following surface treatment agent: Polyether-modified polydimethylsiloxane (BYK Japan KK, BYK-333 (BYK is a registered trademark)) (F) 2.0 parts by weight of the following blue pigment Copper phthalocyanine pigment (Fuji Pigment Co., Ltd. Pigment Blue 15:4) (G) 1.0 part by weight of the following pigment dispersant: Solsperse 6000 (manufactured by LUBRIZOL) The UV-curable ink obtained in this manner had a weight ratio of photopolymerizable monomer of 86.0 wt%, a weight ratio of polyfunctional monomer in the photopolymerizable monomer of 55.0 wt%, a weight ratio of trifunctional or higher monomer in the polyfunctional monomer of 79.5 wt%, and a weight ratio of monofunctional monomer in the photopolymerizable monomer of 45.0 wt%. Next, using this UV-curable ink, a decorative layer was formed by printing a solid monochrome print pattern with a thickness of approximately 22 μm and a square shape of 300 mm on each side using an inkjet printer (VersaUV LEC2-330, manufactured by Roland DG) on a carrier film made of non-stretchable polyester resin (Development Product No. 7, manufactured by Okura Kogyo Co., Ltd.), thereby obtaining the decorative transfer film of Example 1. The decorative layer of this decorative transfer film was exposed to ultraviolet light using an ultraviolet irradiation device (LED-UV385, manufactured by Micro Square Co., Ltd.) at an irradiation intensity of 10 mW / cm 2 , cumulative light intensity 50mJ / cm 2After semi-curing the decorative layer by irradiating it with ultraviolet light, the decorative transfer film and the item to be decorated (the item to be decorated) (a 100mm x 200mm x 3mm ABS resin plate (TM20 manufactured by UMG ABS Co., Ltd.)) were placed in a three-dimensional heating vacuum decoration device (NAVITAS / NATS-612B) so that the semi-cured decorative layer of the decorative transfer film faced the decorated surface of the item, and heated with an IR heater set to 130°C for 45 seconds to perform a pressure transfer process. The decorative transfer item was removed from the device and heated with an ultraviolet irradiation device (LED-UV385 manufactured by Micro Square Co., Ltd.) at an irradiation intensity of 125mW / cm. 2 , cumulative light intensity 3000mJ / cm 2 The semi-cured decorative layer of the decorative transfer article was irradiated with ultraviolet light to fully cure the semi-cured decorative layer, and then the carrier film was peeled off to obtain the decorated article of Example 1. This decorated article was evaluated in accordance with the above items (1) to (3).

[0058] (Examples 2 to 5) Each of the decorated articles of Examples 2 to 5 was obtained in the same manner as in Example 1, except that in Example 1, the blending ratio of each component of the ultraviolet-curable ink was as shown in Table 2, and a decorative transfer film with a decorative layer formed with that ultraviolet-curable ink was used. Each of these decorated articles was evaluated in the above (1) to (3).

[0059] (Comparative Examples 1 to 4) Each of the decorated products of Comparative Examples 1 to 4 was obtained in the same manner as in Example 1, except that in Example 1, the blending ratio of each component of the ultraviolet-curable ink was as shown in Table 3, and a decorative transfer film with a decorative layer formed with that ultraviolet-curable ink was used. Each of these decorated products was evaluated in the above (1) to (3).

[0060] The evaluation results of Examples 1 to 5 are shown in Table 2, and the evaluation results of Comparative Examples 1 to 4 are shown in Table 3, along with the blending ratios of the ultraviolet-curable inks used.

[0061] [Table 2]

[0062] [Table 3]

[0063] From the evaluation results of Examples 1 to 5 shown in Table 2, it was found that when a decorative transfer film was used in which a decorative layer was formed by printing a carrier film with an ultraviolet-curable ink containing a photopolymerizable monomer at 85% by weight or more (see Example 5) of the total weight of the ultraviolet-curable ink, the photopolymerizable monomer being composed of a polyfunctional monomer and a monofunctional monomer, the polyfunctional monomer being contained in a proportion of 55 to 70% by weight (see Examples 1 and 3) of the total weight of the photopolymerizable monomer, and the polyfunctional monomer containing a trifunctional or higher functional monomer at 50% by weight or more (see Example 4) of the total weight of the polyfunctional monomer, the carrier film had good peelability (transferability) after transferring the semi-cured decorative layer to the surface of the article, and the decorative layer of the decorated article obtained by fully curing the transferred decorative layer had excellent adhesion and mechanical strength after curing.

[0064] In contrast, as can be seen from the results of Comparative Example 1 shown in Table 3, when the proportion of photopolymerizable monomer contained in the ultraviolet-curable ink that forms the decorative layer of the decorative transfer film was less than 85% by weight, the mechanical strength of the decorative layer after hardening of the decorated article was unacceptable.

[0065] Furthermore, as can be seen from the results of Comparative Example 2 shown in Table 3, when the proportion of polyfunctional monomers in the photopolymerizable monomers contained in the UV-curable ink was less than 55 wt% of the total photopolymerizable monomers, the peelability of the carrier film of the decorative transfer film after transfer to an article was unacceptable, and the adhesion of the decorative layer after curing of the decorated article was unacceptable. Furthermore, as can be seen from the results of Comparative Example 3, when the proportion of polyfunctional monomers in the photopolymerizable monomers contained in the UV-curable ink was more than 70 wt% of the total photopolymerizable monomers, the adhesion of the decorative layer after curing of the decorated article was unacceptable.

[0066] Furthermore, as can be seen from the results of Comparative Example 4 shown in Table 3, when the proportion of trifunctional or higher monomers contained in the polyfunctional monomers constituting the UV-curable ink was less than 50% by weight relative to the total weight of the polyfunctional monomers, the peelability (transferability) of the carrier film of the decorative transfer film after transfer to an article was unacceptable, and the mechanical strength of the decorative layer after hardening of the decorated article was also unacceptable. [Industrial Applicability]

[0067] The decorative transfer film of the present invention has high industrial applicability because the decorative layer can be printed appropriately by appropriately setting the composition and proportions of the ultraviolet-curable ink, and the decorative layer can be transferred with high workability. [Explanation of symbols]

[0068] 10 Decorative transfer film 10R Remaining transfer film after transfer 12 Carrier Film 14 Decorative layer 14P Semi-hardened decorative layer 14D Fully cured decorative layer 14B Remaining decorative layer 16 inkjet nozzles 18H, 18F light source lamp 20 Pressure transfer means 322U, 22L upper and lower chambers 24 Air intake 26 Article support means 26S Elevating Stage 30 Goods 30D Decorated items UV1, UV2 UV for semi-curing and final curing VP Suction means (vacuum pump) HT heating means

Claims

1. A decorative transfer film comprising a light-transmitting carrier film and a decorative layer printed on the carrier film with ultraviolet-curable ink, wherein the ultraviolet-curable ink of the decorative layer contains 85% by weight or more of photopolymerizable monomers relative to the total weight of the ultraviolet-curable ink, the photopolymerizable monomers are composed of polyfunctional monomers and monofunctional monomers, the polyfunctional monomers are contained in a proportion of 55 to 70% by weight relative to the total weight of the photopolymerizable monomers, and the polyfunctional monomers contain 50% by weight or more of trifunctional or higher functional monomers relative to the total weight of the polyfunctional monomers, and the ultraviolet-curable ink decorative layer is semi-cured.

2. 2. The transfer decoration method according to claim 1, wherein the ultraviolet irradiation conditions when semi-curing the decorative layer are an irradiation intensity of 1 to 100 mW / cm ２ The integrated light amount is 1 to 200 mJ / cm ２ A range of decorative transfer films.

3. 2. The decorative transfer film according to claim 1, wherein the ultraviolet curable ink does not contain a functional oligomer.

4. 2. The decorative transfer film according to claim 1, wherein the ultraviolet curable ink of the decorative layer contains an ultraviolet absorber.

5. The decorative transfer film according to claim 1 , further comprising a light-transmitting functional layer between the carrier film and the decorative layer.

6. a step of transferring the decorative layer of the decorative transfer film onto the surface of the article to be decorated by a pressure transfer means; a step of irradiating ultraviolet light through the light-transmitting carrier film of the decorative transfer film with the transferred decorative layer to fully cure the decorative layer; and a step of peeling and removing the light-transmitting carrier film from the decorative layer, wherein the UV-curable ink of the decorative layer contains 85% by weight or more of a photopolymerizable monomer based on the total weight of the UV-curable ink, the photopolymerizable monomer being composed of a polyfunctional monomer and a monofunctional monomer, the polyfunctional monomer being contained in a proportion of 55 to 70% by weight of the total photopolymerizable monomer, and the polyfunctional monomer containing 50% by weight or more of a trifunctional or higher functional monomer based on the total weight of the polyfunctional monomer.

7. 7. The transfer decoration method according to claim 6, wherein the ultraviolet curable ink does not contain a functional oligomer.

8. 7. The transfer decoration method according to claim 6, wherein the ultraviolet curable ink contains an ultraviolet absorbent.

9. 7. The transfer decoration method according to claim 6, wherein the ultraviolet irradiation conditions when semi-curing the decorative layer are an irradiation intensity of 1 to 100 mW / cm. ２ and the integrated light amount is in the range of 1 to 200 mJ / cm ２ A transfer decoration method that is in the range of.

10. 7. The transfer decoration method according to claim 6, wherein the pressure transfer means for transferring the decorative layer is a transfer method in which the decorative transfer film and the article to be decorated are in contact with each other and the decorative layer is pressed and transferred onto the surface of the article by utilizing the differential pressure between them.

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