JP2024049211A - Thermal transfer sheet - Google Patents

Abstract

[Problem] To provide a thermal transfer sheet capable of suppressing lifting of a protective layer from a transferee. [Solution] The thermal transfer sheet comprises a substrate having a first surface and a second surface, a melt-transfer color material layer, a thermally transferable protective layer, and a pressure layer, the melt-transfer color material layer, the thermally transferable protective layer, and the pressure layer being provided in this order on the first surface of the substrate, and the pressure layer is a layer for at least partially pressing the protective layer in a printed matter comprising an image formed by transferring the melt-transfer color material layer and a protective layer formed by transferring the thermally transferable protective layer, while applying thermal energy to the thermal transfer sheet. [Selected Figure] Figure 1

Description

This disclosure relates to a thermal transfer sheet.

Conventionally, a thermal transfer method using a thermal transfer sheet with a color material layer provided on a substrate has been used as a simple printing method. In the thermal transfer method, the thermal transfer sheet and the transfer recipient are superimposed, and the back surface of the thermal transfer sheet is heated in an image-like manner by a thermal head provided in the thermal transfer printer, to form an image (thermal transfer image) on the transfer recipient (see, for example, Patent Document 1). A printed matter can be obtained by the thermal transfer method.

Thermal transfer methods are mainly divided into melt transfer and sublimation transfer.
The images formed by the thermal transfer method are high density and have excellent sharpness. Therefore, the thermal transfer method is suitable for recording binary images such as characters. The sublimation transfer method can control the amount of migration of the sublimation dye according to the amount of energy applied, so it can form a gradation image with image density controlled for each dot of the thermal head.

A protective layer is placed over the image to improve its durability.

JP 2004-188694 A

Images using the melt transfer method are formed by thermally transferring a melt transfer type color material layer itself, which contains a heat-meltable binder and color material, onto a substrate. Such images usually have a certain degree of thickness. Therefore, when a protective layer is provided on such an image, the protective layer may not be able to adhere sufficiently to the substrate at the contours of the image, and the protective layer may float off the substrate.

The present disclosure aims to provide a thermal transfer sheet that can suppress lifting of the protective layer from the receiving object.

The thermal transfer sheet of one embodiment of the present disclosure comprises a substrate having a first surface and a second surface, a melt-transfer color material layer, a thermally transferable protective layer, and a pressure layer, the melt-transfer color material layer, the thermally transferable protective layer, and the pressure layer being provided in this order on the first surface of the substrate, and the pressure layer is a layer for at least partially pressing the protective layer in a printed matter comprising an image formed by transferring the melt-transfer color material layer and a protective layer formed by transferring the thermally transferable protective layer, while applying thermal energy to the thermal transfer sheet.

The present disclosure provides a thermal transfer sheet that can prevent the protective layer from lifting off the transfer target.

FIG. 1 is a schematic cross-sectional view of one embodiment of the thermal transfer sheet of the present disclosure. FIG. 2 is a schematic cross-sectional view of one embodiment of the thermal transfer sheet of the present disclosure. FIG. 3 is a schematic cross-sectional view of one embodiment of the thermal transfer sheet of the present disclosure. FIG. 4 is a schematic cross-sectional view of one embodiment of the thermal transfer sheet of the present disclosure. FIG. 5 is a schematic cross-sectional view of one embodiment of the thermal transfer sheet of the present disclosure. FIG. 6 is a schematic cross-sectional view of one embodiment of the thermal transfer sheet of the present disclosure. FIG. 7 is a schematic cross-sectional view illustrating lifting and steps in the protective layer of a printed matter. FIG. 8 is a schematic cross-sectional view of an embodiment for explaining the pressing step. FIG. 9 is a schematic cross-sectional view of one embodiment of a print of the present disclosure.

The following describes in detail the embodiments of the present disclosure. The present disclosure can be implemented in many different forms, and is not to be construed as being limited to the description of the embodiments exemplified below. In the drawings, the width, thickness, shape, etc. of each layer may be shown diagrammatically compared to the embodiments in order to clarify the explanation, but these are merely examples and do not limit the interpretation of the present disclosure. In this specification and each figure, elements similar to those already explained with respect to the previous figures are given the same reference numerals, and detailed explanations may be omitted as appropriate.

In the present disclosure, when multiple upper limit candidates and multiple lower limit candidates are given for a certain parameter, the numerical range of the parameter may be constructed by combining any one of the upper limit candidates and any one of the lower limit candidates. As an example, the description "Parameter B is preferably A1 or more, more preferably A2 or more, and even more preferably A3 or more. Parameter B is preferably A4 or less, more preferably A5 or less, and even more preferably A6 or less." will be explained. In this example, the numerical range of parameter B may be A1 or more and A4 or less, A1 or more and A5 or less, A1 or more and A6 or less, A2 or more and A4 or less, A2 or more and A5 or less, A2 or more and A6 or less, A3 or more and A4 or less, A3 or more and A5 or less, or A3 or more and A6 or less.

[Thermal transfer sheet]
In one embodiment, the thermal transfer sheet of the present disclosure is
a substrate having a first surface and a second surface;
a melt transfer type color material layer, a thermal transferable protective layer, and a pressing layer;
Equipped with.

The melt-transfer color material layer, the thermally transferable protective layer, and the pressure layer are provided in this order on the first surface of the substrate. The melt-transfer color material layer, the thermally transferable protective layer, and the pressure layer are provided in this order, for example, in the longitudinal direction of the substrate.

In one embodiment, the melt transfer type color material layer of the thermal transfer sheet of the present disclosure is thermally transferred onto a transferee to form an image on the transferee. Next, the thermally transferable protective layer of the thermal transfer sheet is thermally transferred onto the image to form a protective layer on the transferee that at least covers the image. In this way, a print with excellent image durability can be produced. Furthermore, the pressure layer of the thermal transfer sheet is brought into contact with the protective layer formed on the transferee, and the protective layer is pressed at least partially, for example, at least at the contour part of the image, through the pressure layer while applying thermal energy. In this way, for example, at the contour part of the image, the adhesion between the protective layer and the transferee can be increased. In the obtained print, for example, the lifting of the protective layer from the transferee at the contour part of the image can be suppressed. Therefore, an image having a high resolution pattern and excellent adhesion to the transferee can be formed. In addition, the surface of the protective layer can be roughened by the above-mentioned pressing, so that a matte print can be produced.

In one embodiment, the thermal transfer sheet of the present disclosure is
a substrate having a first surface and a second surface;
a colorant layer, a thermally transferable protective layer, and a pressing layer;
The color material layer, the thermally transferable protective layer, and the pressing layer are provided in this order on the first surface of the substrate. The color material layer, the thermally transferable protective layer, and the pressing layer are provided in this order, for example, in the longitudinal direction of the substrate. The thermally transferable protective layer contains a fluorescent material that emits fluorescence when irradiated with ultraviolet light.

In one embodiment, an image is formed on a receiving body by a thermal transfer process using a color material layer provided in the thermal transfer sheet of the present disclosure. Next, a thermally transferable protective layer provided in the thermal transfer sheet is thermally transferred onto the image to form a protective layer on the receiving body that at least covers the image. In this manner, a print with excellent image durability can be produced. Furthermore, the pressing layer provided in the thermal transfer sheet is brought into contact with the protective layer formed on the receiving body, and the protective layer is at least partially pressed via the pressing layer while applying thermal energy. In this manner, the surface of the protective layer can be roughened, so that a matte printed matter can be produced.

<Substrate>
There are no particular restrictions on the substrate, so long as it has heat resistance sufficient to withstand the thermal energy applied when transferring the colorant layer and the thermally transferable protective layer from the thermal transfer sheet onto the transfer recipient, and has mechanical strength and solvent resistance.
The substrate has a first surface and a second surface opposite the first surface.

The substrate may be, for example, a resin film made of a resin material.
Examples of the resin material include polyester, polyamide, polyolefin, vinyl resin, (meth)acrylic resin, styrene resin, cellulose resin, polyarylate, polyimide, polycarbonate, polysulfone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, polyaramid, polyether ketone, and polyether ether ketone.

Examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene terephthalate-isophthalate copolymer, and terephthalic acid-cyclohexane dimethanol-ethylene glycol copolymer. Examples of polyamides include nylon 6 and nylon 6,6. Examples of polyolefins include polyethylene, polypropylene, and polymethylpentene. Examples of vinyl resins include polyvinyl chloride and vinyl chloride-vinyl acetate copolymer. Examples of (meth)acrylic resins include polymethyl (meth)acrylate. Examples of styrene resins include polystyrene, high impact polystyrene, acrylonitrile-styrene copolymer, and acrylonitrile-butadiene-styrene copolymer. Examples of cellulose resins include cellulose acetate and nitrocellulose.

Among resin films, resin films made of polyesters such as polyethylene terephthalate and polyethylene naphthalate are preferred from the viewpoint of excellent heat resistance, mechanical strength and solvent resistance.
The resin film can contain one or more types of resin materials.

In this disclosure, "(meth)acrylate" includes both "acrylate" and "methacrylate," and "(meth)acrylic" includes both "acrylic" and "methacrylic."

The substrate may be, for example, a paper substrate such as glassine paper, condenser paper, and paraffin paper.

The substrate may be a laminate having multiple layers. For example, a laminate of resin films may be used as the substrate. The laminate of resin films may be produced by, for example, a dry lamination method, a wet lamination method, or an extrusion method. The substrate may be a stretched film or an unstretched film, and from the viewpoint of improving strength, it may be a film stretched uniaxially or biaxially.

The substrate may be subjected to a surface treatment. Examples of surface treatment methods include corona discharge treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, roughening treatment, chemical treatment, plasma treatment, low-temperature plasma treatment, primer treatment, and grafting treatment.

In one embodiment, the substrate is elongated.

The thickness of the substrate is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 1.5 μm or more. The thickness of the substrate is preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. A thermal transfer sheet having such a substrate has, for example, an excellent balance between mechanical strength and the transferability of each layer.

<Colorant Layer>
The thermal transfer sheet of the present disclosure comprises a colorant layer on a first surface of a substrate.
In one embodiment, the thermal transfer sheet of the present disclosure comprises a melt-transfer type color material layer on the first surface of the substrate. In one embodiment, the thermal transfer sheet of the present disclosure comprises a sublimation transfer type color material layer on the first surface of the substrate. The thermal transfer sheet of the present disclosure may comprise a sublimation transfer type color material layer and a melt-transfer type color material layer in surface order on the first surface of the substrate. For example, the thermal transfer sheet may comprise sublimation transfer type color material layers of yellow, magenta, and cyan hues and a melt-transfer type color material layer of black hue in surface order on the first surface of the substrate. Using such a thermal transfer sheet, for example, a gradation image may be formed by a sublimation transfer method, and a character portion may be formed by a melt-transfer method.

A melt-transfer colorant layer is a colorant layer in which a colorant is dispersed in a heat-meltable binder. At least a portion of the melt-transfer colorant layer itself is transferred onto a transfer target during thermal transfer. In one embodiment, the melt-transfer colorant layer contains a heat-meltable binder and a colorant.

Examples of the heat-meltable binder include resin materials and waxes. Examples of the resin materials include polyester, polyurethane, polyamide, polyimide, polycarbonate, polyolefin, (meth)acrylic resin, vinyl resin, styrene resin, cellulose resin, phenoxy resin, and ionomer resin. Examples of the wax include microcrystalline wax, carnauba wax, paraffin wax, Fischer-Tropsch wax, polyethylene wax, wood wax, beeswax, whale wax, ivory wax, wool wax, shellac wax, candelilla wax, petrolactam, polyester wax, partially modified wax, fatty acid ester, and fatty acid amide.
The melt transfer type color material layer may contain both a resin material and a wax.
The melt transfer type color material layer can contain one or more types of heat meltable binders.

The coloring material may be a pigment such as an organic pigment or an inorganic pigment, or may be a dye. Specific examples of the coloring material include black coloring materials such as carbon black, acetylene black, lamp black, aniline black, black smoke, and iron black, white coloring materials such as silica, calcium carbonate, and titanium oxide, cadmium red, cadmium pon red, chrome red, vermilion, red iron oxide, azo pigments, alizarin lake, quinacridone, cochineal lake perylene, yellow ocher, aureolin, cadmium yellow, cadmium orange, chrome yellow, zinc yellow, Naples yellow, nickel yellow, greenish yellow, ultramarine, rock ultramarine, cobalt, phthalocyanine, anthraquinone, indicoid, cinnabar green, cadmium green, chrome green, phthalocyanine, azomethine, perylene, and metal pigments and fluorescent substances described below. Among these, black coloring materials, white coloring materials, metal pigments, and fluorescent substances are preferable.

The hues of the melt-transfer colorant layer include, for example, magenta, yellow, cyan, white, and black, with black being preferred. The melt-transfer colorant layer may be, for example, a magenta layer, a yellow layer, a cyan layer, a white layer, or a black layer, with the black layer being preferred.

The melt-transfer color material layer may contain a metal pigment as a color material. Examples of metal pigments include metal pigments, metal oxide pigments, and coated pigments. When a protective layer is formed on an image containing such a metal pigment, the protective layer is likely to lift off the transferee, for example at the contours of the image. By contacting the pressure layer of the thermal transfer sheet with the protective layer formed on the transferee and pressing the protective layer through the pressure layer while applying thermal energy at least at the contours of the image, such lifting of the protective layer can be suppressed.

Metal pigments include, for example, particles composed of metals such as aluminum, iron, titanium, zirconium, silicon, cerium, nickel, chromium, brass, tin, brass, bronze, zinc, silver, platinum, gold, and indium. Metal oxide pigments include, for example, particles composed of oxides of the metals. Among metal pigments, aluminum particles are preferred, and scaly aluminum pigments, i.e., aluminum flakes, are more preferred.

The coated pigment includes a core material and a coating material that coats the core material.
The material constituting the core material of the coated pigment may be an inorganic material or an organic material. Examples of inorganic materials include natural mica, synthetic mica, glass, aluminum, and alumina. Examples of organic materials include resin materials such as polyester, polyamide, polyolefin, vinyl resin, and (meth)acrylic resin.

Examples of the coating material include metals such as aluminum, iron, titanium, zirconium, silicon, cerium, nickel, chromium, brass, tin, brass, bronze, zinc, silver, platinum, gold, and indium, as well as oxides of the metals. Examples of the metal oxides include titanium oxide and iron oxide. The coating material that covers the core material can be formed, for example, by vapor deposition. In one embodiment, the coating material is preferably a metal from the viewpoint of improving the brilliance of the printed matter. The coating material preferably contains gold or silver, and is more preferably composed of gold or silver.

In one embodiment, the core material preferably contains glass, and more preferably is made of glass. In one embodiment, the coating material is preferably a metal. The coating material preferably contains gold or silver, and more preferably is made of gold or silver. In one embodiment, the coated pigment is a particle of glass coated with a metal, specifically, a particle of glass coated with gold or silver.

In one embodiment, the core material preferably contains mica, and more preferably is composed of mica. In one embodiment, the coating material is preferably a metal oxide. The coating material preferably contains titanium oxide or iron oxide, and more preferably is composed of titanium oxide or iron oxide. In one embodiment, the coated pigment is a particle in which mica is coated with a metal oxide, and more specifically, a particle in which mica is coated with titanium oxide or iron oxide.

The shape of the metal pigment is, for example, spherical, needle-like, or scaly.
The average particle diameter of the metallic pigment is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. The average particle diameter of the metallic pigment is preferably 100 μm or less, more preferably 40 μm or less, and even more preferably 10 μm or less. The average particle diameter of the metallic pigment means the arithmetic mean diameter of each value obtained by observing the vertical cross section of the colorant layer in the thermal transfer sheet with a scanning electron microscope (SEM), randomly selecting 100 particles from the particle group to be measured, and measuring the maximum diameter of each particle.

The melt-transfer color material layer may contain a fluorescent material that emits fluorescence when irradiated with ultraviolet light as a color material. In other words, the melt-transfer color material layer may be a fluorescent color material layer.

Images formed by transferring a melt transfer type colorant layer containing a colorless fluorescent substance and a colored colorant onto a transfer target can be seen under visible light, and fluoresce when irradiated with ultraviolet light. This makes it possible to distinguish the authenticity of printed matter. It is clear that those that fluoresce are originals, and those that do not are copies. Therefore, such images are useful in preventing counterfeiting or copying of printed matter. Examples of printed matter include securities, particularly coupons such as commuter passes, horse racing tickets, gift certificates, gift vouchers, book vouchers, checks and bills, delivery notes, and various ID cards.

An image (hidden pattern image) formed by transferring a colorless melt-transfer type color material layer containing a colorless fluorescent substance as a color material onto a transferee cannot be seen under visible light, but can be seen because it emits fluorescence when irradiated with ultraviolet light. Therefore, such an image is useful for preventing counterfeiting or copying of printed matter. Examples of the printed matter include securities, especially season tickets, horse racing tickets, gift certificates, gift certificates, book vouchers, checks, bills, and other cash vouchers, delivery notes, and various ID cards. When a protective layer is formed on an image containing such a fluorescent substance, for example, a step due to the outline of the image is generated on the surface of the protective layer, and the hidden pattern image may be visible even under visible light. The pressing layer of the thermal transfer sheet and the protective layer formed on the transferee are brought into contact with each other, and the surface of the protective layer is roughened by pressing the protective layer through the pressing layer while applying thermal energy at least in the outline of the image, making it difficult to see the hidden pattern image under visible light.

The fluorescent material is preferably colorless. Examples of fluorescent materials include inorganic materials such as zinc sulfide, zinc silicate, zinc oxide, zinc cadmium sulfide, calcium sulfide, and calcium tungstate, and organic dyes or pigments such as stilbenes such as diaminostilbenzyl sulfonic acid, diaminodiphenyls, imidazoles, thiazoles, coumarins, naphthalimides, and thiophenes.

The melt transfer colorant layer can contain one or more types of colorant.

The content of the heat-meltable binder in the melt-transfer colorant layer is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less.

The content of the colorant in the melt-transfer colorant layer is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, and is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. A thermal transfer sheet having such a melt-transfer colorant layer has, for example, excellent print density and storage stability.

The melt transfer type color material layer may contain additives. Examples of additives include ultraviolet absorbers, light stabilizers, antioxidants, leveling agents, defoamers, and surfactants. Examples of ultraviolet absorbers include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, and triazine-based ultraviolet absorbers. Examples of light stabilizers include hindered amine-based light stabilizers and Ni chelate-based light stabilizers. Examples of antioxidants include hindered phenol-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and lactone-based antioxidants.
The melt transfer type color material layer may contain one or more additives.

A sublimation transfer color material layer is a color material layer in which a sublimation dye is dissolved or dispersed in a binder. During thermal transfer, the sublimation dye contained in the sublimation transfer color material layer is transferred to a transfer target. In one embodiment, the sublimation transfer color material layer contains a binder and a sublimation dye.

The binder may be, for example, a resin material, such as polyester, polyurethane, polyamide, polyimide, polycarbonate, polyolefin, (meth)acrylic resin, vinyl resin, styrene resin, cellulose resin, phenoxy resin, or ionomer resin.
The sublimation transfer colorant layer may contain one or more types of binder.

Examples of sublimable dyes include diarylmethane dyes, triarylmethane dyes, thiazole dyes, merocyanine dyes, pyrazolone dyes, methine dyes, indoaniline dyes, acetophenone azomethine dyes, pyrazoloazomethine dyes, xanthene dyes, oxazine dyes, thiazine dyes, azine dyes, acridine dyes, azo dyes, spiropyran dyes, indolinospiropyran dyes, fluoran dyes, naphthoquinone dyes, anthraquinone dyes, and quinophthalone dyes.
The sublimation transfer color material layer can contain one or more sublimation dyes.

The binder content in the sublimation transfer colorant layer is preferably 20% by weight or more, more preferably 30% by weight or more, and is preferably 95% by weight or less, more preferably 90% by weight or less.

The content of the sublimation dye in the sublimation transfer color material layer is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less. A thermal transfer sheet having such a sublimation transfer color material layer has, for example, excellent print density and storage stability.

The sublimation transfer colorant layer may contain one or more of the above additives.

The sublimation transfer colorant layer may be cured with a curing agent. Examples of the curing agent include epoxy resin curing agents, isocyanate curing agents, and carbodiimide curing agents. One or more types of curing agents may be used.

The thickness of the colorant layer, such as the melt transfer colorant layer and the sublimation transfer colorant layer, is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. The thickness of the colorant layer is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less.

The colorant layer can be formed, for example, by applying a coating liquid containing the above-mentioned materials to a substrate by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, and rod coating, and then drying the applied liquid.

<Thermal Transferable Protective Layer>
The thermal transfer sheet of the present disclosure comprises a thermally transferable protective layer on a first surface of a substrate.
The thermally transferable protective layer means a protective layer that is peeled off from the substrate and transferred onto a transferee by applying thermal energy to the thermal transfer sheet. That is, the thermally transferable protective layer constitutes a transfer layer in the thermal transfer sheet that can be peeled off by applying thermal energy. The thermally transferable protective layer is a layer that is transferred onto an image to protect the image after an image is formed on a transferee using the thermal transfer sheet.

The thermally transferable protective layer may contain, as a coloring material, a fluorescent material that emits fluorescence when irradiated with ultraviolet light. The fluorescent material is preferably colorless. Examples of fluorescent materials include inorganic materials such as zinc sulfide, zinc silicate, zinc oxide, zinc cadmium sulfide, calcium sulfide, and calcium tungstate, and organic dyes or pigments such as stilbenes such as diaminostilbenzyl sulfonic acid, diaminodiphenyls, imidazoles, thiazoles, coumarins, naphthalimides, and thiophenes.

In one embodiment, the protective layer comprises a release layer and an adhesive layer. That is, in one embodiment, the protective layer comprises a release layer and an adhesive layer provided on the surface of the release layer opposite the surface facing the substrate. In one embodiment, the adhesive layer contacts the transfer target when the thermally transferable protective layer is transferred onto the transfer target. In one embodiment, the release layer constitutes the surface layer of the print obtained when the thermally transferable protective layer is transferred onto the transfer target.

(Release Layer)
In one embodiment, the thermally transferable protective layer includes a release layer as the layer that is located closest to the substrate among the layers that constitute the thermally transferable protective layer. The thermally transferable protective layer that includes the release layer has, for example, excellent transferability. The release layer is transferred as a part of the thermally transferable protective layer during thermal transfer, and acts to improve the scratch resistance of the image.

The release layer, in one embodiment, contains a binder.
Examples of the binder include resin materials, such as (meth)acrylic resins, styrene resins, vinyl resins, polyesters, cellulose resins, polyamides, polyurethanes, polycarbonates, phenoxy resins, epoxy resins, silicone-modified versions of these resins, ultraviolet absorbing resins, and ionizing radiation curable resins.

Examples of ionizing radiation curable resins include resins obtained by crosslinking and curing a radical polymerizable polymer or a radical polymerizable oligomer by irradiating it with ionizing radiation. Specifically, examples include resins obtained by adding a photopolymerization initiator to a radical polymerizable polymer or a radical polymerizable oligomer as necessary, and polymerizing and crosslinking the polymer by irradiating it with an electron beam or ultraviolet light.

The release layer preferably contains a (meth)acrylic resin.
The glass transition temperature (Tg) of the (meth)acrylic resin is preferably 140° C. or less, more preferably 130° C. or less, and even more preferably 120° C. or less. The Tg of the (meth)acrylic resin is preferably 60° C. or more, more preferably 70° C. or more, and even more preferably 80° C. or more. A release layer containing a (meth)acrylic resin having such a Tg can be pressed well and deformed, for example, by a pressing step described later. In this specification, Tg is a value determined by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012.

The weight average molecular weight (Mw) of the (meth)acrylic resin is preferably 300,000 or less, more preferably 200,000 or less, and even more preferably 150,000 or less. The Mw of the (meth)acrylic resin is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 20,000 or more. A release layer containing a (meth)acrylic resin having such an Mw can be pressed and deformed well, for example, by the pressing step described below. In this specification, Mw means a value measured by gel permeation chromatography using polystyrene as a standard substance, and is a value measured by a method conforming to JIS K7252-1:2016.

The release layer can contain one or more binders.
The content of the binder in the release layer is preferably 80% by mass or more, and more preferably 85% by mass or more. Such a release layer has, for example, excellent durability.

The release layer may contain a lubricant.
Examples of lubricants include wax, metal salts of higher fatty acids, organic particles, and inorganic particles. Examples of metal salts of higher fatty acids include zinc stearate, zinc stearyl phosphate, calcium stearate, and magnesium stearate. Examples of organic particles include (meth)acrylic resins, crosslinked polystyrene, and fluororesins (e.g., polytetrafluoroethylene). Examples of inorganic particles include silica, clay, talc, titanium oxide, calcium carbonate, and barium sulfate.

Examples of waxes include synthetic waxes, natural waxes, higher saturated fatty acids, higher saturated monohydric alcohols, higher fatty acid esters, and higher fatty acid amides. Examples of synthetic waxes include paraffin wax, microcrystalline wax, silicone wax, oxidized wax, polyester wax, and polyethylene wax. Examples of natural waxes include beeswax, spermaceti, Japan wax, rice bran wax, carnauba wax, candelilla wax, and montan wax. Examples of higher saturated fatty acids include margaric acid, lauric acid, myristic acid, palmitic acid, stearic acid, furoic acid, and behenic acid. Examples of higher saturated monohydric alcohols include stearyl alcohol and behenyl alcohol. Examples of higher fatty acid esters include fatty acid esters of sorbitan. Examples of higher fatty acid amides include stearic acid amide and oleic acid amide.

The release layer preferably contains a polyethylene wax.
The melting point (Tm) of the polyethylene wax is preferably 100° C. or higher and preferably 140° C. or lower. In this specification, Tm is a value determined by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012.

The average particle diameter of the polyethylene wax is preferably 1 μm or more, more preferably 5 μm or more, and preferably 15 μm or less, more preferably 12 μm or less. The average particle diameter of the polyethylene wax is determined by observing the vertical cross section of the release layer of the thermal transfer sheet with a scanning electron microscope (SEM), randomly selecting 100 particles from the particle group to be measured, measuring the maximum diameter of each particle, and calculating the arithmetic mean diameter of the obtained values.

The release layer can contain one or more lubricants.
The content of the lubricant in the release layer is preferably 1% by mass or more, more preferably 2% by mass or more, and is preferably 20% by mass or less, more preferably 15% by mass or less. Such a release layer is excellent in, for example, the abrasion resistance of the printed matter.

In one embodiment, the release layer contains a (meth)acrylic resin as the binder and a polyethylene wax as the lubricant.

The release layer may contain one or more of the above additives.
The content of the additive in the release layer is preferably 20% by mass or less, and more preferably 15% by mass or less.

The thickness of the release layer is preferably 0.1 μm or more, more preferably 0.3 μm or more, and even more preferably 0.5 μm or more. The thickness of the release layer is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 3 μm or less. A thermally transferable protective layer having such a release layer can, for example, suppress the occurrence of transfer defects and the like, and can provide sufficient protective function to the transfer target.

The release layer can be formed, for example, by applying a coating liquid containing the above-mentioned materials to, for example, the substrate or release layer by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, and rod coating, and then drying.

(Adhesive Layer)
In one embodiment, the thermally transferable protective layer includes an adhesive layer provided on the surface of the release layer opposite to the surface facing the substrate. The adhesive layer is a layer that improves adhesion between the thermally transferable protective layer and the object to be transferred. The adhesive layer can be formed of, for example, a conventionally known pressure-sensitive adhesive or heat-sensitive adhesive.

In one embodiment, the adhesive layer contains a resin material.
Examples of the resin material include vinyl resin, (meth)acrylic resin, acid-modified polyolefin, polyester, polyurethane, cellulose resin, silicone resin, and fluororesin, as well as various resins modified with silicone or fluorine.

The adhesive layer preferably contains polyester.
The glass transition temperature (Tg) of the polyester is preferably 120° C. or lower, more preferably 110° C. or lower. The Tg of the polyester is preferably 50° C. or higher, more preferably 70° C. or higher. An adhesive layer containing a polyester having such a Tg can be well pressed and deformed, for example, by the pressing step described later.

The number average molecular weight (Mn) of the polyester is preferably 20,000 or less, more preferably 15,000 or less, and even more preferably 12,000 or less. The Mn of the polyester is preferably 2,000 or more, more preferably 3,000 or more, and even more preferably 4,000 or more. An adhesive layer containing a polyester having such an Mn can be pressed and deformed well, for example, by the pressing step described below. In this specification, Mn means a value measured by gel permeation chromatography using polystyrene as a standard substance, and is a value measured by a method conforming to JIS K7252-1:2016.

The adhesive layer preferably contains a (meth)acrylic resin.
The glass transition temperature (Tg) of the (meth)acrylic resin is preferably 120° C. or lower, more preferably 110° C. or lower. The Tg of the (meth)acrylic resin is preferably 50° C. or higher, more preferably 70° C. or higher. An adhesive layer containing a (meth)acrylic resin having such a Tg can be well pressed and deformed, for example, by the pressing step described below.

The weight average molecular weight (Mw) of the (meth)acrylic resin is preferably 100,000 or less, more preferably 80,000 or less, and even more preferably 50,000 or less. The Mw of the (meth)acrylic resin is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 15,000 or more. An adhesive layer containing a (meth)acrylic resin having such an Mw can be well pressed and deformed, for example, by the pressing process described below.

In one embodiment, the adhesive layer contains a polyester and a (meth)acrylic resin. The content ratio of the polyester to the (meth)acrylic resin is not particularly limited. The content of the (meth)acrylic resin in the adhesive layer is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 30 parts by mass or more, and is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 75 parts by mass or less, relative to 100 parts by mass of polyester.

The adhesive layer can contain one or more types of resin materials.
The content of the resin material in the adhesive layer is preferably 80% by mass or more, and more preferably 85% by mass or more.

The adhesive layer may contain one or more of the above additives.

The thickness of the adhesive layer is preferably 0.5 μm or more. The thickness of the adhesive layer is preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 5 μm or less.

The adhesive layer can be formed, for example, by applying a coating liquid containing the above-mentioned materials to the release layer by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, and rod coating, and then drying the coating.

<Pressure layer>
The thermal transfer sheet of the present disclosure comprises a pressure layer on a first surface of a substrate.
The pressing layer is a layer for pressing the protective layer of a printed matter having an image and a protective layer, for example, at least in the contour portion of the image, while applying thermal energy. For example, the pressing layer of the thermal transfer sheet may be brought into contact with the protective layer of the printed matter having an image and a protective layer, and the entire surface of the protective layer may be pressed by the thermal head of a thermal transfer printer, or the protective layer may be partially pressed based on pattern data.

The pressing layer may be provided on the first surface of the substrate in a pattern having projections and recesses. Examples of the pattern of the pressing layer include a lattice pattern such as a checkerboard pattern, a line pattern, and a wave pattern. By applying the above-mentioned pressing to the entire surface of the protective layer using a thermal transfer sheet having such a pressing layer, a projection and recess pattern corresponding to the pattern of the pressing layer can be formed on the protective layer formed on the transfer target. In this way, a printed matter having a certain projection and recess pattern can be produced, and a certain visual effect can be imparted to the printed matter.

The pressure layer, in one embodiment, contains a binder and particles.
Examples of the binder include resin materials, such as polyolefin, polyester, polyamide, polyimide, polyurethane, vinyl resin, (meth)acrylic resin, phenol resin, melamine resin, polyol resin, silicone resin, silicone-modified (meth)acrylic resin, fluororesin, fluoro-modified resin, and cellulose resin.
The pressing layer may contain one or more binders.

Particles include, for example, inorganic particles and organic particles.
The pressing layer can contain one or more types of particles.

Examples of inorganic particles include particles composed of oxides, clay minerals, carbonates, hydroxides, sulfates, silicates, graphite, saltpeter, boron nitride, and the like. Examples of oxides include silica, alumina, zinc oxide, titanium oxide, zirconium oxide, and magnesium oxide. Examples of clay minerals include talc, kaolin, and clay. Examples of carbonates include calcium carbonate and magnesium carbonate. Examples of hydroxides include aluminum hydroxide and magnesium hydroxide. Examples of sulfates include calcium sulfate and barium sulfate. Examples of silicates include aluminum silicate and magnesium silicate.

Examples of organic particles include particles made of resin (resin particles). Resins that form resin particles include thermosetting resins and thermoplastic resins, such as melamine resin, benzoguanamine resin, phenolic resin, silicone resin, urethane resin, amide resin, (meth)acrylic resin, fluororesin, styrene resin, olefin resin, and copolymers of monomers that make up these resins. One or more types of resins can be used.

The shape of the particles may be any of irregular, spherical, elliptical, cylindrical, and prismatic. The surface of the particles may be treated with a surface treatment agent such as a silane coupling agent.

The average particle diameter of the particles is preferably 0.1 μm or more, more preferably 0.3 μm or more, even more preferably 0.5 μm or more, and particularly preferably 1 μm or more. The average particle diameter of the particles is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 6 μm or less, and particularly preferably 4 μm or less. The average particle diameter of the particles is determined by observing the vertical cross section of the pressing layer in the thermal transfer sheet with a scanning electron microscope (SEM), randomly selecting 100 particles from the particle group to be measured, measuring the maximum diameter of each particle, and calculating the arithmetic mean diameter of the obtained values.

The ratio of the particle content to the binder content in the compression layer (PV ratio = particle content/binder content) is preferably 0.01 or more, more preferably 0.03 or more, and even more preferably 0.05 or more, by mass. The above ratio (PV ratio) in the compression layer is preferably 0.5 or less, more preferably 0.4 or less, and even more preferably 0.3 or less, by mass.

The pressing layer can have a surface unevenness structure caused by particles, for example. By contacting the pressing layer of the thermal transfer sheet with a protective layer formed on the transfer target and applying thermal energy to the protective layer through the pressing layer, a matte-finished printed product can be obtained.

The pressing layer may contain particles in a pattern when viewed in a plan view. A plan view refers to viewing the pressing layer from the normal direction of the surface of the pressing layer. That is, in the pressing layer, when viewed in a plan view, the density of the particles may vary in a pattern, for example, a lattice pattern such as a checkerboard pattern, a line pattern, or a wave pattern. By performing the above-mentioned pressing on the entire surface of the protective layer using a thermal transfer sheet having such a pressing layer, a fine uneven pattern corresponding to the particle density pattern can be formed on the protective layer formed on the transfer target. In this way, a printed matter having a constant fine uneven pattern can be produced, and a certain visual effect can be imparted to the printed matter.

The pressing layer may be cured with a curing agent. Examples of the curing agent include aluminum chelate curing agents, isocyanate curing agents, and epoxy resin curing agents. One or more types of curing agents may be used. The amount of the curing agent used is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, per 100 parts by mass of the binder.

The pressing layer may further contain a release agent. Such a pressing layer is prevented from fusing to the transfer object and the protective layer formed on the surface thereof in the pressing step described below. Therefore, the pressing layer of the thermal transfer sheet can be easily peeled off from the transfer object and the protective layer formed on the surface thereof.

Examples of the release agent include metal soaps such as zinc stearate, zinc stearyl phosphate, calcium stearate, and magnesium stearate, as well as silicone oils, fluorine compounds, phosphoric acid esters, fatty acid amides, polyethylene waxes, carnauba waxes, and paraffin waxes. The binder resins and/or particles described above may also function as the release agent.
The pressing layer may contain one or more types of release agents.

When the pressing layer contains a binder resin and/or a release agent other than particles that can also function as a release agent, the content of the release agent in the pressing layer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and is preferably 10% by mass or less, more preferably 5% by mass or less.

The pressing layer may contain one or more of the above additives.

The thickness of the pressing layer is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. The thickness of the pressing layer is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less.

The pressing layer can be formed, for example, by applying a coating liquid containing the above-mentioned materials to, for example, the substrate or the release layer by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, and rod coating, and then drying.

The arithmetic mean height Sa of the surface of the pressing layer is preferably 0.13 μm or more, more preferably 0.25 μm or more, and even more preferably 0.50 μm or more. Such a pressing layer has a surface unevenness structure with a sufficiently large unevenness height, and can sufficiently roughen the protective layer in the pressing step described below. The surface Sa of the pressing layer is preferably 2.4 μm or less, more preferably 1.5 μm or less, and even more preferably 1.2 μm or less.

The maximum height Sz of the surface of the pressing layer is preferably 9.0 μm or more, more preferably 12.0 μm or more, and even more preferably 15.0 μm or more. Such a pressing layer has a surface unevenness structure with a sufficiently large unevenness height, and can sufficiently roughen the protective layer in the pressing process described below. The surface Sz of the pressing layer is preferably 75 μm or less, more preferably 50 μm or less, and even more preferably 40 μm or less.

In the thermal transfer sheet of the present disclosure, it is preferable that at least one of the aspect ratio (Str) of the surface texture of the pressing layer surface, the arithmetic mean curvature of the peaks (Spc), and the developed area ratio (Sdr) of the interface is within the following range.

Str is preferably 0.60 or more, more preferably 0.75 or more, and preferably 3.2 or less, more preferably 2 or less. Spc is preferably 320 (1/mm) or more, more preferably 1600 (1/mm) or more, and preferably 8000 (1/mm) or less, more preferably 5500 (1/mm) or less. Sdr is preferably 0.02 or more, more preferably 0.8 or more, and preferably 10 or less, more preferably 3 or less.

The parameters that indicate the surface condition of the above-mentioned pressed layer, such as Sa, are measured in accordance with ISO 25178-2:2012. The surface of the pressed layer means the surface of the pressed layer opposite to the surface facing the substrate. Details of the measurement conditions are described in the Examples section. The above-mentioned parameters can be adjusted, for example, by the average particle size of the particles in the pressed layer, the particle content, the thickness of the pressed layer, etc.

<Release Layer>
The thermal transfer sheet of the present disclosure may include a first release layer between the substrate and the melt-transfer colorant layer. The thermal transfer sheet of the present disclosure may include a second release layer between the substrate and the thermally transferable protective layer.

The release layer is optionally provided on the first surface of the substrate so that the melt-transferable colorant layer and/or the thermally transferable protective layer can be easily transferred from the substrate during thermal transfer. The release layer is a layer that remains on the first surface of the substrate during thermal transfer.

The first release layer and the second release layer may be the same layer or different layers. For example, a first release layer may be formed on the first surface of the substrate, a melt-transfer color material layer may be formed on the first release layer, and then a second release layer may be formed on the first surface of the substrate, and a thermally transferable protective layer may be formed on the second release layer. For example, a release layer corresponding to the first release layer and the second release layer may be integrally formed on the first surface of the substrate, and a melt-transfer color material layer and a thermally transferable protective layer may be formed on the release layer in surface order. In this way, the first release layer and the second release layer may be integrated.

The release layer, in one embodiment, contains a binder.
Examples of the binder include resin materials. Examples of the resin materials include (meth)acrylic resins, vinyl resins, polyurethanes, polyamides, polyimides, phenolic resins, melamine resins, polyol resins, silicone resins, silicone-modified (meth)acrylic resins, fluororesins, fluororesins, and cellulose resins. The content of the binder in the release layer is preferably 50% by mass or more.
The release layer may contain one or more binders.

The release layer, in one embodiment, further contains a release agent.
Examples of the release agent include metal soaps such as zinc stearate, zinc stearyl phosphate, calcium stearate, and magnesium stearate, as well as waxes such as silicone oil, fluorine compounds, phosphate esters, fatty acid amides, polyethylene wax, carnauba wax, and paraffin wax. The content of the release agent in the release layer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more. The content of the release agent in the release layer is preferably 10% by mass or less, more preferably 5% by mass or less.
The release layer may contain one or more types of release agents.

The release layer may contain one or more of the above additives.

The thickness of the release layer is preferably 0.1 μm or more, more preferably 0.2 μm or more. The thickness of the release layer is preferably 3 μm or less, more preferably 2 μm or less. A thermal transfer sheet having such a release layer has excellent transferability of, for example, the melt-transfer type colorant layer and/or the thermal transferable protective layer.

The release layer can be formed, for example, by applying a coating liquid containing the above-mentioned materials to a substrate by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, and rod coating, and then drying the applied liquid.

<Primer layer>
The thermal transfer sheet of the present disclosure may have a first primer layer between the substrate and the pressure layer. When the thermal transfer sheet of the present disclosure has a sublimation transfer colorant layer, the thermal transfer sheet may have a second primer layer between the substrate and the sublimation transfer colorant layer. Such a thermal transfer sheet has, for example, excellent interlayer adhesion between the substrate and the pressure layer, and excellent interlayer adhesion between the substrate and the sublimation transfer colorant layer.

In one embodiment, the primer layer contains a resin material, such as polyester, vinyl resin, (meth)acrylic resin, polystyrene, polyamide, polyether, urethane resin, and cellulose resin.
The primer layer can contain one or more types of resin materials.

The primer layer may contain one or more of the above additives.

The thickness of the primer layer is preferably 0.05 μm or more.
The thickness of the primer layer is preferably 2 μm or less.

The primer layer can be formed, for example, by applying a coating liquid containing the above-mentioned materials to a substrate by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, and rod coating, and then drying the applied coating.

<Back layer>
In one embodiment, the thermal transfer sheet of the present disclosure may include a back layer on the surface of the substrate opposite to the surface on which the transfer layer is provided. A thermal transfer sheet including such a back layer can, for example, suppress the occurrence of sticking and wrinkles during thermal transfer.

In one embodiment, the back layer contains a resin material. Examples of the resin material include polyolefin, styrene resin, vinyl resin, polyester, polyurethane, polyether, polyamide, polyimide, polyamideimide, polycarbonate, cellulose resin, and silicone-modified versions of these.

In one embodiment, the back layer contains a cured resin obtained by curing a hydroxyl-containing resin with an isocyanate curing agent. Such a back layer can, for example, suppress the occurrence of sticking and wrinkles during thermal transfer. Examples of hydroxyl-containing resins include polyvinyl alcohol, polyvinyl butyral, polyvinyl acetal, and (meth)acrylic polyol. Examples of isocyanate curing agents include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, p-phenylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, triphenylmethane triisocyanate, and tris(isocyanatophenyl)thiophene.

The molar equivalent ratio (-NCO/-OH) of the isocyanate group (-NCO) of the isocyanate curing agent to the hydroxyl group (-OH) of the hydroxyl group-containing resin is preferably 1.5 or more. Such a back layer has excellent heat resistance and can reduce the thermal energy transmitted to the substrate and color material layer, etc., and therefore has excellent printing properties.

The content of the cured resin in the back layer is preferably 50% by mass or more, more preferably 55% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less. A thermal transfer sheet having such a back layer has, for example, excellent printing properties.

The back layer may contain additives for the purpose of improving slip properties, etc. Examples of additives include release agents, organic particles, inorganic particles, and organic-inorganic particles. Examples of release agents include metal soaps such as zinc stearate, zinc stearyl phosphate, calcium stearate, and magnesium stearate, as well as silicone oils, fluorine compounds, phosphate esters, fatty acid amides, and waxes such as polyethylene wax, carnauba wax, and paraffin wax. Examples of organic particles include fluorine resins. Examples of inorganic particles include silica, clay, talc, and calcium carbonate. Examples of organic-inorganic particles include silicone resins.

The content of the above additives in the back layer is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less. A thermal transfer sheet having such a back layer has, for example, excellent slip properties.

From the viewpoint of improving heat resistance and slip resistance, the thickness of the back layer is preferably 0.1 μm or more, more preferably 0.3 μm or more, and is preferably 5 μm or less, more preferably 2 μm or less.

The back layer can be formed, for example, by applying a coating liquid containing the above-mentioned materials to a substrate by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating, and rod coating, and then drying the applied liquid.

<Construction of Thermal Transfer Sheet>
The thermal transfer sheet 1 of the embodiment shown in FIG. 1 includes a substrate 10, and a color material layer 20, a thermally transferable protective layer 30, and a pressing layer 40, which are provided in surface order on a first surface 11 of the substrate 10.

The thermal transfer sheet 1 of the embodiment shown in FIG. 2 comprises a substrate 10, a melt-transfer color material layer 22, a thermally transferable protective layer 30, and a pressing layer 40, which are provided in surface order on the first surface 11 of the substrate 10.

The thermal transfer sheet 1 of the embodiment shown in FIG. 3 has a sublimation transfer color material layer 24, a melt transfer color material layer 22, a thermal transferable protective layer 30, and a pressing layer 40 in this order on the first surface 11 of the substrate 10.

The thermal transfer sheet 1 of the embodiment shown in FIG. 4 has a sublimation transfer yellow layer 24Y, a sublimation transfer magenta layer 24M, a sublimation transfer cyan layer 24C, a melt transfer black layer 22B, a thermal transferable protective layer 30, and a pressing layer 40 arranged in this order on the first surface 11 of the substrate 10.

The thermal transfer sheet 1 of the embodiment shown in FIG. 5A has, on a first surface 11 of a substrate 10, a sublimation transfer yellow layer 24Y, a sublimation transfer magenta layer 24M, a sublimation transfer cyan layer 24C, a melt transfer fluorescent color material layer 22UV, a thermal transferable protective layer 30, and a pressing layer 40, in this order on the first surface 11.
The embodiment of the thermal transfer sheet 1 shown in Figure 5B has, on the first surface 11 of the substrate 10, a sublimation transfer yellow layer 24Y, a sublimation transfer magenta layer 24M, a sublimation transfer cyan layer 24C, a thermal transferable protective layer 30UV containing a fluorescent substance, and a pressing layer 40, in this order on the surface.

The thermal transfer sheet 1 of the embodiment shown in FIG. 6 has a sublimation transfer yellow layer 24Y, a sublimation transfer magenta layer 24M, a sublimation transfer cyan layer 24C, a melt transfer black layer 22B, a melt transfer fluorescent color material layer 22UV, a thermal transferable protective layer 30, and a pressing layer 40 arranged in this order on the first surface 11 of the substrate 10.

The thermal transfer sheet 1 of the embodiment shown in Figures 1 to 6 may further include a back layer (not shown) on the second surface 12 of the substrate 10. The thermal transfer sheet 1 of the embodiment shown in Figures 1 to 6 may further include a primer layer (not shown) between the substrate 10 and the pressing layer 40. The thermal transfer sheet 1 of the embodiment shown in Figures 3 to 6 may further include a primer layer (not shown) between the substrate 10 and the sublimation transfer color material layer 24. The thermal transfer sheet 1 of the embodiment shown in Figures 2 to 6 may further include a release layer (not shown) between the substrate 10 and the melt transfer color material layer 22. The thermal transfer sheet 1 of the embodiment shown in Figures 1 to 6 may further include a release layer (not shown) between the substrate 10 and the thermal transferable protective layer 30.

A combination of at least one color material layer and a thermally transferable protective layer and a pressing layer provided in surface sequence on the color material layer is referred to as a "unit" (U). The thermal transfer sheet of the present disclosure may have one unit repeated on the first surface of a long substrate, i.e., multiple units provided in surface sequence in the longitudinal direction of the substrate. A panel of "one unit" can be used to form one screen's worth of image on the substrate.

The color material layer included in one unit may be single or multiple. When the color material layer included in one unit is multiple, that is, when it is a color material layer group, each color material layer is provided in surface sequence. In one embodiment, one unit is composed of a yellow layer (Y), a magenta layer (M), a cyan layer (C), a black layer (BK), a thermally transferable protective layer (OP), and a pressing layer. In one embodiment, one unit is composed of a yellow layer (Y), a magenta layer (M), a cyan layer (C), a fluorescent color material layer, a thermally transferable protective layer (OP), and a pressing layer. In one embodiment, one unit is composed of a yellow layer (Y), a magenta layer (M), a cyan layer (C), a black layer (BK), a fluorescent color material layer, a thermally transferable protective layer (OP), and a pressing layer. In one embodiment, one unit is composed of a black layer (BK), a thermally transferable protective layer (OP), and a pressing layer. In one embodiment, one unit is composed of a fluorescent color material layer, a thermally transferable protective layer (OP), and a pressing layer. In one embodiment, one unit consists of a black layer (BK), a fluorescent color material layer, a thermally transferable protective layer (OP), and a pressing layer. In one embodiment, one unit consists of a color material layer, a thermally transferable protective layer (OP), and a pressing layer.

The yellow layer (Y), magenta layer (M) and cyan layer (C) are preferably sublimation transfer type colorant layers. The black layer (BK) is preferably a melt transfer type colorant layer.

The area of the pressing layer is, for example, equal to or greater than the area of one screen of each of the sublimation transfer color material layer, the melt transfer color material layer, the fluorescent color material layer, and the thermal transfer protective layer. The areas of each of these layers are periodically arranged in a certain order.

[Printed matter manufacturing method and printed matter]
In one embodiment, the method for producing a print product according to the present disclosure includes:
A step of preparing the thermal transfer sheet and the transferee of the present disclosure (preparation step), wherein the thermal transfer sheet comprises a substrate having a first surface and a second surface, a melt-transfer type color material layer, a thermally transferable protective layer, and a pressing layer;
a step of thermally transferring a melt-transfer type color material layer provided on the thermal transfer sheet onto a transfer receiving material to form a first image on the transfer receiving material (image forming step);
a step of thermally transferring a thermally transferable protective layer of the thermal transfer sheet onto the first image to form a protective layer on the transferee that covers at least the first image (protective layer transfer step);
A pressing layer of the thermal transfer sheet is brought into contact with a protective layer formed on a transferee, and the protective layer is at least partially pressed through the pressing layer while applying thermal energy to the thermal transfer sheet to obtain a printed matter (pressing step).
Equipped with.

In one embodiment, the method for producing a print product according to the present disclosure includes:
A step of preparing the thermal transfer sheet and the transferee of the present disclosure (preparation step), wherein the thermal transfer sheet comprises a substrate having a first surface and a second surface, a color material layer, a thermally transferable protective layer, and a pressing layer;
A step of forming an image on a transfer medium by a thermal transfer process using a color material layer provided on the thermal transfer sheet (image forming step);
a step of thermally transferring a thermally transferable protective layer of the thermal transfer sheet onto the image to form a protective layer on the transferee that at least covers the image (protective layer transfer step);
a step of contacting a pressure layer of the thermal transfer sheet with a protective layer formed on a transferee, and at least partially pressing the protective layer through the pressure layer while applying thermal energy to the thermal transfer sheet to obtain a printed matter (pressing step);
Equipped with.

In one embodiment, the manufacturing method disclosed herein provides a printed matter that includes a transfer target, an image that includes characters, line drawings, patterns, symbols, and combinations of these, and a protective layer provided on the image.

<Preparation process>
In the preparation step, the thermal transfer sheet of the present disclosure and a transfer-receiving object are prepared.
The details of the thermal transfer sheet are as described above, and will not be described here.

The transfer object may be, for example, the resin film, glass substrate, metal substrate, ceramic substrate, cloth substrate, and paper substrate described as the substrate in the thermal transfer sheet, as well as laminated substrates thereof. The transfer object may be a card substrate, for example, a card substrate mainly composed of polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, or polycarbonate. The cloth substrate may be, for example, a substrate formed from fibers such as man-made fibers, such as nylon fibers, polyester fibers, rayon fibers, acetate fibers, acrylic fibers, vinylon fibers, polypropylene fibers, and polyvinylidene chloride fibers, as well as natural fibers, such as cotton, silk, hemp, and wool. The paper substrate may be, for example, fine paper, plain paper, art paper, coated paper, resin-coated paper, cast-coated paper, cardboard, synthetic paper, and impregnated paper. The transfer object may be, for example, a thermal transfer image receiving sheet comprising a substrate and a receiving layer provided on one side of the substrate. The transfer object may have an image, may be colored, and may be transparent.

A card substrate is preferable as the object to be transferred. According to the present disclosure, a printed product having excellent design can be produced using a card substrate.

<Image forming process>
In the image forming step, in one embodiment, a melt-transfer colorant layer of the thermal transfer sheet is thermally transferred onto a transferee to form a first image (hereinafter also referred to as a "melt-transfer image") on the transferee. When the thermal transfer sheet has a sublimation transfer colorant layer, in the image forming step, a sublimation dye contained in the sublimation transfer colorant layer of the thermal transfer sheet may be thermally transferred onto the transferee to further form a second image (hereinafter also referred to as a "sublimation transfer image") on the transferee. In one embodiment, in the image forming step, the colorant layer of the thermal transfer sheet is heated according to image information, and a colorant element (e.g., a melt-transfer colorant layer or a sublimation dye) is transferred to the transferee to form an image.

In the image forming process, for example, the sublimation dye contained in the sublimation transfer color material layer of the thermal transfer sheet may be thermally transferred to the transferee to form a sublimation transfer image on the transferee, and then the melt transfer color material layer of the thermal transfer sheet may be thermally transferred onto the transferee on which the sublimation transfer image has been formed, to form a melt transfer image on the transferee. For example, the sublimation transfer color material layer of the thermal transfer sheet is brought into contact with the surface of the transferee, and then thermal energy is applied to a desired area on the thermal transfer sheet to form a sublimation transfer image on the transferee. For example, the melt transfer color material layer of the thermal transfer sheet is brought into contact with the surface of the transferee, and then thermal energy is applied to a desired area on the thermal transfer sheet to form a melt transfer image on the transferee.

In the image forming process, for example, an image can be formed using a thermal transfer printer having a thermal head. In one embodiment, the thermal transfer sheet and the transferee are superimposed and passed between the thermal head and platen roll of the thermal transfer printer, and the thermal transfer sheet is heated using the thermal head to form an image. The thermal transfer recording method for forming an image on the transferee is at least a melt transfer method, and is preferably a combination of a sublimation transfer method and a melt transfer method. The sublimation transfer method and the melt transfer method may be combined, for example, to form a gradation image by the sublimation transfer method and a character portion by the melt transfer method.

The melt transfer type image is an image formed by thermally transferring the melt transfer type color material layer of the thermal transfer sheet. Therefore, the melt transfer type image has a certain thickness. The thickness of the melt transfer type image is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. The thickness of the melt transfer type image is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less.

<Protective Layer Transfer Step>
In one embodiment, in the protective layer transfer step, a thermally transferable protective layer provided in the thermal transfer sheet is thermally transferred onto the melt-transfer type image to form a protective layer on the transferee that covers at least the melt-transfer type image. The protective layer is formed on the melt-transfer type image formed on the transferee.
In one embodiment, in the protective layer transfer step, a thermally transferable protective layer provided in the thermal transfer sheet is thermally transferred onto the image to form a protective layer on the transfer recipient that at least covers the image. The protective layer is formed on the image formed on the transfer recipient.

In the protective layer transfer step, for example, the thermally transferable protective layer can be transferred using a thermal transfer printer having a thermal head. In one embodiment, the thermal transfer sheet and the transferee are overlapped so that the thermally transferable protective layer of the thermal transfer sheet and the image forming surface of the transferee are in contact with each other. The overlapped thermal transfer sheet and the transferee are passed between the thermal head and platen roll of the thermal transfer printer, and the thermal transfer sheet is heated using the thermal head. In this way, the thermally transferable protective layer is transferred so as to at least cover the image, such as the melt transfer type image, formed on the transferee.

In the protective layer transfer step, thermal energy may be applied to an area of the thermally transferable protective layer of the thermal transfer sheet that corresponds to the entire surface of the image forming surface, thereby transferring the protective layer to the entire surface of the image forming surface. In this case, the amount of thermal energy applied may be uniform on the image forming surface or may vary depending on the location.

In the protective layer transfer step, thermal energy may be applied to an area of the thermally transferable protective layer of the thermal transfer sheet that corresponds to a portion of the image forming surface, thereby partially transferring the protective layer to the image forming surface.

When a thermal head is used as the thermal transfer means for the thermally transferable protective layer, the same thermal head as that used for image formation may be used, or a different thermal head may be used. In the present disclosure, the thermal transfer means for image formation and the thermal transfer means for the thermally transferable protective layer can be performed in-line using a single thermal transfer printer.

<Pressing process>
In the pressing process, a pressing layer provided on the thermal transfer sheet is brought into contact with a protective layer formed on the transfer recipient, and the protective layer is at least partially pressed through the pressing layer while applying thermal energy to the thermal transfer sheet, thereby obtaining a printed matter.

The print comprises a substrate, an image, and a protective layer. The image is formed on the substrate. In one embodiment, the print comprises at least a melt transfer type image, and may further comprise a sublimation transfer type image. The protective layer is formed so as to cover at least the melt transfer type image. In one embodiment, the print comprises a melt transfer type image and/or a sublimation transfer type image. The protective layer is formed so as to cover at least the image. The protective layer may be formed on the entire surface of the image forming surface.

As described above, the melt transfer type image has a certain thickness. If the distance between images (for example, the distance between the lines that make up a character) is small, the protective layer may not be sufficiently transferred to the recesses corresponding to the distance, and the protective layer transferred onto the transferee may float from the transferee (see space AA in FIG. 7A). Such a protective layer does not adhere well to the transferee, and may peel off, for example, when the print is used. In the pressing step, the protective layer is pressed while applying thermal energy, thereby reducing the floating of the protective layer, and therefore the protective layer can be well adhered to the transferee (see FIG. 8 and FIG. 9A). In addition, by roughening the protective layer, or by roughening it in a pattern, visual effects such as matte processing (matte finish) can be obtained.

In the pressing step, for example, the protective layer on at least the contour portion of the melt-transfer image may be pressed through the pressing layer while applying thermal energy. In the pressing step, for example, the thermal energy applied to the protective layer on the contour portion of the melt-transfer image may be greater than the thermal energy applied to the protective layer on the sublimation transfer image.

Of the melt transfer type images, it is desirable that colorless fluorescent color material images that contain colorless fluorescent substances as color materials are not visible under visible light. However, such fluorescent color material images also have a certain thickness and an uneven pattern. Therefore, a step may be generated in the protective layer transferred onto the fluorescent color material image, and the fluorescent color material image may be visible under visible light (see step BB in Figure 7B). Here, in the pressing process, the protective layer is pressed while applying thermal energy to roughen the surface of the protective layer, making it possible to make the fluorescent color material image difficult to see under visible light (see Figures 8 and 9B).

In the pressing step, for example, the protective layer formed on the transferee can be pressed using a thermal transfer printer having a thermal head. In one embodiment, the thermal transfer sheet and the transferee are overlapped so that the pressing layer of the thermal transfer sheet and the protective layer forming surface of the transferee are in contact with each other. The overlapped thermal transfer sheet and the transferee are passed between the thermal head and platen roll of the thermal transfer printer, and the thermal transfer sheet is heated using the thermal head. In this way, the protective layer formed on the transferee can be pressed via the pressing layer.

In the pressing step, thermal energy may be applied to an area of the pressing layer of the thermal transfer sheet that corresponds to the entire surface of the protective layer on the transfer recipient, to press the entire surface of the protective layer. In this case, the amount of thermal energy applied may be uniform across the protective layer, or may vary depending on the location. In this way, a printed product having a matte protective layer over the entire surface can be obtained.

In the pressing step, thermal energy may be applied to an area of the pressing layer of the thermal transfer sheet that corresponds to a portion of the protective layer on the transfer recipient, thereby partially pressing the protective layer. For example, thermal energy may be applied in a pattern to the pressing layer of the thermal transfer sheet to press the protective layer in a pattern. Examples of patterns include lattice patterns such as checkerboard patterns, lines, and waves. In this way, a printed matter having a certain uneven pattern can be produced, and a certain visual effect can be imparted to the printed matter.

In the method for producing a printed matter disclosed herein, the conveying speed (printing speed) of the thermal transfer sheet is preferably 0.01 mm/msec or more and 0.30 mm/msec or less, and more preferably 0.02 mm/msec or more and 0.17 mm/msec or less. It is desirable that the conveying speed of the thermal transfer sheet is within the above ranges in each of the image forming process, the protective layer transfer process, and the pressing process.

＜Printed materials＞
In the print obtained by the manufacturing method of the present disclosure, the arithmetic mean height Sa of the surface of the protective layer is preferably 0.13 μm or more, more preferably 0.25 μm or more, and even more preferably 0.50 μm or more. The surface Sa of the protective layer is preferably 2.4 μm or less, more preferably 1.5 μm or less, and even more preferably 1.2 μm or less.

The maximum height Sz of the surface of the protective layer is preferably 3.0 μm or more, more preferably 4.0 μm or more, and even more preferably 5.5 μm or more. The maximum height Sz of the surface of the protective layer is preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less.

In the printed matter obtained by the manufacturing method of the present disclosure, it is preferable that at least one of the aspect ratio (Str) of the surface texture of the protective layer surface, the arithmetic mean curvature of the peaks (Spc), and the developed area ratio (Sdr) of the interface is within the following ranges.

Str is preferably 0.60 or more, more preferably 0.75 or more, and preferably 3.2 or less, more preferably 2 or less. Spc is preferably 400 (1/mm) or more, more preferably 2000 (1/mm) or more, and preferably 9000 (1/mm) or less, more preferably 6000 (1/mm) or less. Sdr is preferably 0.02 or more, more preferably 0.8 or more, and preferably 10 or less, more preferably 3 or less.

The parameters that indicate the surface condition of the protective layer, such as Sa, are measured in accordance with ISO 25178-2:2012. The surface of the protective layer refers to the surface of the protective layer opposite to the surface facing the transfer object.

The present disclosure relates to, for example, the following [1] to [15].
[1] A thermal transfer sheet comprising a substrate having a first surface and a second surface, a melt-transfer color material layer, a thermally transferable protective layer, and a pressure layer, the melt-transfer color material layer, the thermally transferable protective layer, and the pressure layer being provided in this order on the first surface of the substrate, and the pressure layer being a layer for at least partially pressing the protective layer in a printed matter comprising an image formed by transferring the melt-transfer color material layer and a protective layer formed by transferring the thermally transferable protective layer, while applying thermal energy to the thermal transfer sheet.
[2] The thermal transfer sheet according to [1], wherein the pressing layer contains a binder and particles.
[3] The thermal transfer sheet according to [1] or [2], wherein the arithmetic mean height Sa of the surface of the pressing layer is 0.13 μm or more.
[4] The thermal transfer sheet according to any one of [1] to [3] above, wherein the thickness of the melt-transfer colorant layer is 0.1 μm or more and 20 μm or less.
[5] The thermal transfer sheet according to any one of [1] to [4], wherein the thermal transfer sheet has at least a pigment layer containing a heat-meltable binder and a pigment as the melt-transfer color material layer.
[6] The thermal transfer sheet according to any one of [1] to [5], wherein the thermal transfer sheet has at least a metal-based pigment layer containing a heat-fusible binder and a metal-based pigment as the melt-transfer type color material layer.
[7] The thermal transfer sheet according to any one of [1] to [6], wherein the thermal transfer sheet has at least a fluorescent color material layer containing a heat-meltable binder and a fluorescent substance that emits fluorescence when irradiated with ultraviolet light, as the melt-transfer type color material layer.
[8] The thermal transfer sheet according to any one of [1] to [7], further comprising a sublimation transfer color material layer containing a binder and a sublimation dye, the sublimation transfer color material layer, the melt transfer color material layer, the thermal transfer protective layer and the pressing layer being provided in surface sequence on the first surface of the substrate in this order.
[9] A thermal transfer sheet comprising a substrate having a first surface and a second surface, a color material layer, a thermally transferable protective layer and a pressure layer, the color material layer, the thermally transferable protective layer and the pressure layer being provided in this order on the first surface of the substrate, the thermally transferable protective layer containing a fluorescent substance that emits fluorescence when irradiated with ultraviolet light, and the pressure layer being a layer for at least partially pressing the protective layer in a printed matter comprising an image transferred using the color material layer and a protective layer formed by transferring the thermally transferable protective layer while applying thermal energy to the thermal transfer sheet.
[10] A method for producing a printed matter, comprising the steps of: preparing the thermal transfer sheet and a recipient described in any one of [1] to [7]; thermally transferring the melt-transfer color material layer of the thermal transfer sheet onto the recipient to form a first image on the recipient; thermally transferring the thermally transferable protective layer of the thermal transfer sheet onto the first image to form a protective layer on the recipient that covers at least the first image; and contacting the pressing layer of the thermal transfer sheet with the protective layer formed on the recipient, and at least partially pressing the protective layer via the pressing layer while applying thermal energy to the thermal transfer sheet to obtain a printed matter.
[11] A method for producing a printed matter, comprising the steps of: preparing the thermal transfer sheet and a receiving body described in [8] above; thermally transferring a sublimation dye contained in the sublimation transfer color material layer of the thermal transfer sheet to the receiving body to form a second image on the receiving body; thermally transferring the melt transfer color material layer of the thermal transfer sheet onto the receiving body on which the second image has been formed to form a first image on the receiving body; thermally transferring the thermal transferable protective layer of the thermal transfer sheet onto the first image to form a protective layer on the receiving body that covers at least the first image; and contacting the pressing layer of the thermal transfer sheet with the protective layer formed on the receiving body, and at least partially pressing the protective layer via the pressing layer while applying thermal energy to the thermal transfer sheet to obtain a printed matter.
[12] The method for producing a printed matter according to [10] or [11] above, wherein the thickness of the first image is 0.1 μm or more and 20 μm or less.
[13] The method for producing a printed matter according to any one of [10] to [12] above, wherein the object is a card substrate.
[14] A method for producing a printed matter, comprising the steps of: preparing the thermal transfer sheet and a receiving body described in [9] above; forming an image on the receiving body by a thermal transfer process using the color material layer provided in the thermal transfer sheet; thermally transferring the thermally transferable protective layer provided in the thermal transfer sheet onto the image to form a protective layer on the receiving body that at least covers the image; and contacting the pressing layer provided in the thermal transfer sheet with the protective layer formed on the receiving body, and at least partially pressing the protective layer via the pressing layer while applying thermal energy to the thermal transfer sheet, to obtain a printed matter.
[15] The method for producing a printed matter according to [14], wherein the object is a card substrate.

The thermal transfer sheet of the present disclosure will be described below based on examples, but the thermal transfer sheet of the present disclosure is in no way limited to the examples. In the following description, "parts by mass" will simply be written as "parts". The amounts of components contained in the coating liquid described below are solid content amounts.

[Example 1]
A polyethylene terephthalate film (PET film) having a thickness of 6 μm was prepared as a substrate. A coating liquid for a release layer having the following composition was applied to a part of the first surface of the PET film, and dried to form a release layer having a thickness of 0.3 μm. A coating liquid for a black pigment-containing layer having the following composition was applied to the release layer, and dried to form a black pigment-containing layer having a thickness of 1.7 μm on the release layer. The coating liquid for a release layer having the following composition was applied to the release layer in surface order with the black pigment-containing layer, and dried to form a release layer having a thickness of 0.8 μm on the release layer. The coating liquid for an adhesive layer having the following composition was applied to the release layer, and dried to form an adhesive layer having a thickness of 1.1 μm on the release layer. The thermally transferable protective layer is composed of a release layer and an adhesive layer. A coating liquid for a pressing layer having the following composition was applied to a part of the first surface of the PET film in surface order with the thermally transferable protective layer, and dried to form a pressing layer having a thickness of 1.7 μm. A coating solution for the back layer having the following composition was applied to the second surface of the PET film and dried to form a back layer having a thickness of 1 μm. In this way, a thermal transfer sheet was obtained.

<Release layer coating liquid>
1.25 parts urethane resin 3.75 parts polyvinyl acetal (S-LEC (registered trademark) KS-5, Sekisui Chemical Co., Ltd.)
Toluene 47.5 parts Isopropyl alcohol 47.5 parts

<Coating solution for black pigment-containing layer>
PVC-S3 Black (Showa Ink Co., Ltd.) 1 part

<Coating solution for release layer>
(Meth)acrylic resin 24 parts (Thermolac LP-45M-30, Soken Chemical Co., Ltd.,
Tg: 105 ° C., Mw: 80,000)
Lubricant 1 part (Slip Agent B, Showa Ink Co., Ltd.)
Methyl ethyl ketone (MEK) 45 parts Toluene 30 parts

<Coating solution for adhesive layer>
Polyester 40 parts (Vylon (registered trademark) 700, Toyobo Co., Ltd., Tg: 90°C, Mn: 5,000)
Acrylic acid ester copolymer 20 parts (UVA-40KT, BASF Japan Co., Ltd.)
Tg: 85°C, Mw: 25,000)
MEK 30 parts Toluene 30 parts

<Coating liquid for pressure layer>
Silicone modified acrylic resin 81.27 parts (Celltop (registered trademark) 226, Daicel Chemical Industries, Ltd.)
Silica particles 15.61 parts (Sylysia (registered trademark) 310P, average particle size 2.7 μm,
Fuji Silysia Chemical Ltd.)
Aluminum chelate curing agent 3.13 parts (CAT-A, Daicel Chemical Industries, Ltd.)
・Toluene 200 parts ・Ethyl acetate 200 parts

<Coating solution for back layer>
Polyvinyl butyral 2 parts (S-LEC (registered trademark) BX-1, Sekisui Chemical Co., Ltd.)
Polyisocyanate 9.2 parts (Burnoc (registered trademark) D750, DIC Corporation)
Phosphate ester surfactant 1.3 parts (Plysurf (registered trademark) A208N, Daiichi Kogyo Seiyaku Co., Ltd.)
Talc 0.3 parts (Microace (registered trademark) P-3, Nippon Talc Kogyo Co., Ltd.)
Toluene 43.6 parts MEK 43.6 parts

[Comparative Example 1]
A thermal transfer sheet was obtained in the same manner as in Example 1, except that no pressing layer was formed.

[Production of printed matter]
Using the test printer described below, the black pigment-containing layer of the thermal transfer sheet obtained in each of the Examples and Comparative Examples was transferred to a PVC card (standard white card, manufactured by Dai Nippon Printing Co., Ltd.) to form an image, and a thermally transferable protective layer was transferred onto the image to form a protective layer. In the case of the thermal transfer sheet of Example 1, the protective layer was further pressed with a pressing layer to obtain a printed matter.
(Test Printer)
Thermal head: Kyocera Corporation, KEE-57-12GAN2-STA
Heating element average resistance: 3303Ω
Main scanning direction resolution: 300 dpi (dots per inch)
Sub-scanning direction resolution: 300 dpi
Line speed: 3.0 msec./line
Printing start temperature: 35°C
Pulse duty ratio: 70%

[Adhesion of protective layer]
The adhesion of the protective layer to the card substrate in the printed matter was evaluated as follows.
Visual evaluation: It was visually confirmed whether or not the protective layer had peeled off.
Tape peeling: Cellophane tape was applied to the surface of the protective layer of the card substrate and then peeled off.
In the case of the print obtained using the thermal transfer sheet of Example 1, lifting of the protective layer was not observed, and peeling of the protective layer did not occur. In the case of the print obtained using the thermal transfer sheet of Comparative Example 1, lifting of the protective layer was observed, and peeling of the protective layer also occurred.

[Measurement of arithmetic mean height Sa, etc.]
Using a shape analysis laser microscope (Keyence Corporation, product name: VK-X150), the arithmetic mean height Sa of the surface of the pressure layer of the thermal transfer sheet and the surface of the protective layer of the printed matter was measured in a measurement range of 270 μm × 200 μm in accordance with ISO 25178-2: 2012. The magnification of the objective lens was set to 20 times, and tilt correction was performed on the entire image before analysis.

On the surface of the pressing layer in the thermal transfer sheet of Example 1, Sa was 0.626 μm, Sz was 24.098 μm, Str was 0.905, Spc was 3823 (1/mm), and Sdr was 1.307.

The surface of the protective layer of the print obtained in Example 1 had Sa of 0.637 μm, Sz of 8.441 μm, Str of 0.894, Spc of 4704 (1/mm), and Sdr of 1.386.

The surface of the protective layer of the print obtained in Comparative Example 1 had Sa of 0.117 μm, Sz of 2.945 μm, Str of 0.564, Spc of 392 (1/mm), and Sdr of 0.01473.

Reference Signs List 1: Thermal transfer sheet 2: Printed material 10: Substrate 11: First surface of substrate 12: Second surface of substrate 20: Coloring material layer 22: Melt transfer type coloring material layer 24: Sublimation transfer type coloring material layer 30: Thermal transferable protective layer 40: Pressing layer 60: Transferred body 70: Thermal head

Claims (15)

a substrate having a first surface and a second surface;
a melt transfer type color material layer, a thermal transferable protective layer, and a pressing layer;
A thermal transfer sheet comprising:
the melt transfer color material layer, the thermal transferable protective layer, and the pressing layer are provided in this order on the first surface of the base material,
the pressing layer is a layer for at least partially pressing the protective layer in a print product having an image formed by transferring the melt-transfer color material layer and a protective layer formed by transferring the thermal transferable protective layer while applying thermal energy to the thermal transfer sheet;
Thermal transfer sheet. The thermal transfer sheet according to claim 1, wherein the pressure layer contains a binder and particles. The thermal transfer sheet according to claim 1, wherein the arithmetic mean height Sa of the surface of the pressing layer is 0.13 μm or more. The thermal transfer sheet according to claim 1, wherein the thickness of the melt-transfer colorant layer is 0.1 μm or more and 20 μm or less. The thermal transfer sheet according to claim 1, wherein the thermal transfer sheet has at least a pigment layer containing a heat-meltable binder and a pigment as the melt-transfer color material layer. The thermal transfer sheet according to claim 1, wherein the thermal transfer sheet has at least a metal-based pigment layer containing a heat-meltable binder and a metal-based pigment as the melt-transfer color material layer. The thermal transfer sheet according to claim 1, wherein the thermal transfer sheet has at least a fluorescent color material layer containing a thermally meltable binder and a fluorescent material that emits fluorescence when irradiated with ultraviolet light as the melt-transfer type color material layer. the thermal transfer sheet further comprises a sublimation transfer colorant layer containing a binder and a sublimation dye;
the sublimation transfer color material layer, the melt transfer color material layer, the thermal transferable protective layer, and the pressing layer are provided on the first surface of the base material in this order,
The thermal transfer sheet according to claim 1 . a substrate having a first surface and a second surface;
a colorant layer, a thermally transferable protective layer, and a pressing layer;
A thermal transfer sheet comprising:
the color material layer, the thermally transferable protective layer, and the pressing layer are provided in this order on the first surface of the base material,
the thermally transferable protective layer contains a fluorescent material that emits fluorescence when irradiated with ultraviolet light,
the pressing layer is a layer for at least partially pressing the protective layer in a print product having an image transferred and formed using the color material layer and a protective layer formed by transferring the thermally transferable protective layer while applying thermal energy to the thermal transfer sheet;
Thermal transfer sheet. A step of preparing the thermal transfer sheet and a transfer-receiving body according to claim 1;
a step of thermally transferring the melt-transfer type color material layer of the thermal transfer sheet onto the transfer-receiving material to form a first image on the transfer-receiving material;
a step of thermally transferring the thermally transferable protective layer of the thermal transfer sheet onto the first image to form a protective layer on the transfer recipient that covers at least the first image;
a step of contacting the pressure layer of the thermal transfer sheet with the protective layer formed on the transferee, and at least partially pressing the protective layer through the pressure layer while applying thermal energy to the thermal transfer sheet, thereby obtaining a printed matter;
A method for manufacturing a printed matter comprising the steps of: A step of preparing the thermal transfer sheet and a transfer-receiving body according to claim 8;
a step of thermally transferring a sublimation dye contained in the sublimation transfer color material layer of the thermal transfer sheet to the transfer recipient, thereby forming a second image on the transfer recipient;
a step of thermally transferring the melt-transfer type color material layer of the thermal transfer sheet onto the transfer-receiving body on which the second image has been formed, thereby forming a first image on the transfer-receiving body;
a step of thermally transferring the thermally transferable protective layer of the thermal transfer sheet onto the first image to form a protective layer on the transfer recipient that covers at least the first image;
a step of contacting the pressure layer of the thermal transfer sheet with the protective layer formed on the transferee, and at least partially pressing the protective layer through the pressure layer while applying thermal energy to the thermal transfer sheet, thereby obtaining a printed matter;
A method for manufacturing a printed matter comprising the steps of: The method for producing a print according to claim 10 or 11, wherein the thickness of the first image is 0.1 μm or more and 20 μm or less. The method for producing a printed matter according to claim 10 or 11, wherein the transfer medium is a card substrate. A step of preparing the thermal transfer sheet and a transfer-receiving body according to claim 9;
forming an image on the transfer medium by a thermal transfer process using the color material layer of the thermal transfer sheet;
a step of thermally transferring the thermally transferable protective layer of the thermal transfer sheet onto the image to form a protective layer on the transfer-receiving body that at least covers the image;
a step of contacting the pressure layer of the thermal transfer sheet with the protective layer formed on the transferee, and at least partially pressing the protective layer through the pressure layer while applying thermal energy to the thermal transfer sheet, thereby obtaining a printed matter;
A method for manufacturing a printed matter comprising the steps of: The method for producing a printed matter according to claim 14, wherein the transfer object is a card substrate.