JP2022047377A - Thermal transfer sheet - Google Patents

Abstract

To provide a thermal transfer sheet that can achieve both the adhesion and plastic material resistance of a transfer layer in a printed object obtained from the thermal transfer sheet and that can achieve improved transferability in high energy printing.SOLUTION: The present invention discloses a thermal transfer sheet having a base material, and a transfer layer provided on one side of the base material in a peelable manner. The transfer layer is a monolayer containing a (meth)acrylic resin and a vinyl chloride-vinyl acetate copolymer.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to thermal transfer sheets.

As a means for increasing the durability of the printed matter by the thermal transfer method, a transfer sheet provided with a thermal transferable protective layer (hereinafter, also referred to as a transfer layer) is used on the image obtained by the thermal transfer method, and a thermal head or a heating roll is used. By transferring the transfer layer by a heating means such as, the transfer layer is formed on the image. By providing such a transfer layer on the printed image, it is possible to improve the wear resistance and the chemical resistance of the thermoplastic material of the image.

Further, in the thermal transfer sheet provided with the transfer layer as described above, when the heat transfer sheet is heated from the substrate side by the heating means, the transfer layer needs to be quickly and surely transferred onto the image and adhered.
For example, in Patent Document 1, as a thermal transferable protective layer, a protective layer transfer sheet having an adhesive layer for adhering to a thermal transfer image receiving sheet at the time of transfer and a layer containing a (meth) acrylic resin having excellent plasticity resistance (meth). Thermal transfer sheet) is disclosed.

Japanese Unexamined Patent Publication No. 2020-97132

By the way, in the above-mentioned thermal transfer sheet, it is desired to simplify the structure of the transfer layer from the viewpoint of cost reduction and productivity improvement. The present inventors considered that cost reduction and productivity improvement can be realized by making the transfer layer of the thermal transfer sheet a single layer.

However, the present inventors have noticed that it is difficult to achieve both the adhesiveness of the transfer layer and the thermoplastic resistance in the printed matter obtained from the thermal transfer sheet with one layer.

Now, the present inventors have found that even if the transfer layer is a single layer, by using two specific types of resins for the transfer layer, both the adhesiveness of the transfer layer and the thermoplastic resistance can be achieved at the same time. In addition, by making the transfer layer a single layer in this way, the present inventors can reproduce the matte texture, and even when high energy is received from the thermal print head during transfer, the transfer layer is cohesively broken. I found that it can be suppressed.

Therefore, it is an object of the present disclosure to provide a thermal transfer sheet that can achieve both adhesiveness of a transfer layer and thermoplastic resistance in a printed matter obtained from a thermal transfer sheet and that has improved transferability in high-energy printing. Is.

The present disclosure is a thermal transfer sheet comprising a substrate and a transfer layer removably provided on one surface side of the substrate.
The transfer layer is a thermal transfer sheet which is a single layer containing a (meth) acrylic resin and a vinyl chloride-vinyl acetate copolymer.

According to the present disclosure, it is possible to provide a thermal transfer sheet having both adhesiveness and a thermoplastic resistance of a transfer layer in a printed matter obtained from a thermal transfer sheet and improved transferability in high energy printing.

It is a schematic cross-sectional view which shows one Embodiment of the thermal transfer sheet of this disclosure. It is a schematic cross-sectional view which shows one Embodiment of the thermal transfer sheet of this disclosure. It is a schematic cross-sectional view which shows one Embodiment of the thermal transfer sheet of this disclosure. It is a schematic cross-sectional view which shows one Embodiment of the thermal transfer sheet of this disclosure.

[Thermal transfer sheet]
The thermal transfer sheet of the present disclosure includes a base material and a transfer layer removably provided on one surface side of the base material.

Hereinafter, the thermal transfer sheet of the present disclosure will be described with reference to the drawings.

In one embodiment, as shown in FIG. 1, the thermal transfer sheet 10 includes a substrate 11 and a transfer layer 12. As shown in FIG. 1, the transfer layer 12 is provided on one surface side of the base material 11. As shown in FIG. 1, the transfer layer 12 is a single layer. As shown in FIG. 1, the transfer layer 12 is directly laminated on the base material 11.

In one embodiment, as shown in FIG. 2, the thermal transfer sheet 10 includes a base material 11, a transfer layer 12, and a release layer 13. As shown in FIG. 2, the transfer layer 12 is provided on one surface side of the base material 11. As shown in FIG. 2, the transfer layer 12 is a single layer. As shown in FIG. 2, the thermal transfer sheet 10 includes a release layer 13 between the base material 11 and the transfer layer 12.

In one embodiment, as shown in FIG. 3, the thermal transfer sheet 10 includes a base material 11, a transfer layer 12, and a coloring material layer 14. As shown in FIG. 3, the transfer layer 12 is provided on one surface side of the base material 11. As shown in FIG. 3, the transfer layer 12 is a single layer. As shown in FIG. 3, the transfer layer 12 is directly laminated on the base material 11. As shown in FIG. 3, the thermal transfer sheet 10 includes a coloring material layer 14 so as to be surface-sequential to the transfer layer 12.

In one embodiment, as shown in FIG. 4, the thermal transfer sheet 10 includes a base material 11, a transfer layer 12, a mold release layer 13, and a coloring material layer 14. As shown in FIG. 4, the transfer layer 12 is provided on one surface side of the base material 11. As shown in FIG. 4, the transfer layer 12 is a single layer. As shown in FIG. 4, the thermal transfer sheet 10 includes a release layer 13 between the base material 11 and the transfer layer 12. As shown in FIG. 4, the thermal transfer sheet 10 includes a coloring material layer 14 so as to be surface-sequential to the transfer layer 12.

The thermal transfer sheet 10 may include a primer layer between the base material 11 and the coloring material layer 14 (not shown).
The thermal transfer sheet 10 may be provided with a back surface layer on the surface side of the base material 11 opposite to the transfer layer 12 (not shown).

The layer configurations of the thermal transfer sheet 10 can be combined as appropriate.

Hereinafter, each layer that can be provided by the thermal transfer sheet of the present disclosure will be described.

<Transfer layer>
The transfer layer is a layer that is transferred from the thermal transfer sheet to the transferred body or the like by heating.
The transfer layer is a single layer containing a (meth) acrylic resin and a vinyl chloride-vinyl acetate copolymer.

In the heat transfer sheet of the present disclosure, the transfer layer contains a (meth) acrylic resin and a vinyl chloride-vinyl acetate copolymer, so that the adhesiveness and plastic resistance of the transfer layer in the printed matter obtained from the heat transfer sheet (hereinafter referred to as “plastic material”). , Simply referred to as "adhesiveness" and "plastic material resistance", respectively).
Specifically, when the transfer layer contains a (meth) acrylic resin, the transfer layer can be imparted with thermoplastic resistance. Since the transfer layer contains a vinyl chloride-vinyl acetate copolymer, it is possible to impart adhesive performance to the transfer layer while imparting plastic resistance to the transfer layer.
Further, when the transfer layer contains the (meth) acrylic resin, the glossiness (hereinafter, also simply referred to as “glossiness”) in the printed matter can be improved.
Further, when the transfer layer contains a vinyl chloride-vinyl acetate copolymer, the transferability of the transfer layer in the thermal transfer sheet (hereinafter, also simply referred to as “transferability”) can be improved.
Further, when the transfer layer contains a (meth) acrylic resin, the back phenomenon in the thermal transfer sheet can be suppressed when the thermal transfer sheet of the present disclosure includes a coloring material layer. That is, the back inhibitory property (hereinafter, also simply referred to as "back inhibitory property") in the thermal transfer sheet can be improved.
Here, the back phenomenon will be described by taking as an example a thermal transfer sheet having a base material, a back surface layer on one surface side of the base material, and a color material layer and a transfer layer sequentially on the other surface side of the base material. do. The back phenomenon is that when the thermal transfer sheet is wound, the dye contained in the coloring material layer is transferred to the back layer (kick phenomenon), and the dye transferred to the back layer is the transfer layer or coloring material provided in the thermal transfer sheet. It is to re-migrate to the layer.

In the thermal transfer sheet of the present disclosure, by making the transfer layer a single layer, it is possible to suppress the cohesive failure of the transfer layer even when high energy is received from the thermal print head at the time of transfer by reproducing a matte texture or the like. That is, the transferability of the thermal transfer sheet in high-energy printing (hereinafter, also simply referred to as "high-energy transferability") can be improved. The reason will be explained below.
When the transfer layer is a multilayer, for example, as in the thermal transfer sheet of JP-A-2020-97132, when the transfer layer is a laminate of a protective layer and an adhesive layer, an interface exists between the protective layer and the adhesive layer. If such an interface is present, it may be peeled off at the interface in the transfer layer during transfer, which makes transfer control difficult. Further, since the matte transfer (matt mode) requires a very large printing energy as compared with the normal transfer (gloss mode), the control of the transfer becomes more difficult.
The heat transfer sheet of the present disclosure realizes a transfer layer having both adhesiveness and plastic resistance even if it is a single layer by combining a (meth) acrylic resin and a vinyl chloride-vinyl acetate copolymer. can. Further, by making the transfer layer a single layer, that is, by eliminating the above-mentioned interface in the transfer layer, it becomes easy to control the transfer and the aggregation and destruction of the transfer layer can be suppressed.

From the viewpoint of adhesiveness, the heat transfer sheet of the present disclosure is preferably used for a transferred body provided with a receiving layer containing a vinyl chloride-vinyl acetate copolymer.

Examples of the (meth) acrylic resin contained in the transfer layer include a (meth) acrylic resin and a copolymer of a (meth) acrylic acid monomer and / or a (meth) acrylate monomer and another monomer. ..
In the present disclosure, "(meth) acrylic" means to include both "acrylic" and "methacrylic". By "(meth) acrylate" is meant to include both "acrylate" and "methacrylate".

Examples of the (meth) acrylic resin include a (meth) acrylic resin having a (meth) acrylic acid monomer as a constituent unit, a (meth) acrylic resin having a (meth) acrylate as a constituent unit, and the like. These (meth) acrylic resins may be homopolymers of one kind of monomer or derivatives thereof, or copolymers of two or more kinds of monomers or derivatives thereof.

Examples of the (meth) acrylic acid monomer and the (meth) acrylate monomer include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylic acrylate, cyclohexyl (meth) acrylate, and normal butyl. (Meta) acrylate, isobutyl (meth) acrylate, secondary butyl (meth) acrylate, tertiary butyl (meth) acrylate, isobonyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, and 2-ethyl-2. -Adamantyl (meth) acrylate and the like can be mentioned.

In the (meth) acrylic resin, the other monomer is copolymerizable with the (meth) acrylic acid monomer or the (meth) acrylate monomer. Other monomers include, for example, styrene, (maleic anhydride), fumaric acid, divinylbenzene, vinylbiphenyl, vinylnaphthalene, diphenylethylene, vinyl acetate, vinyl chloride, vinyl fluoride, vinyl alcohol, acrylonitrile, acrylamide, butadiene, etc. Alicyclic olefin monomers such as isoprene, isobutene, 1-butene, 2-butene, N-vinyl-2-pyrrolidone, dicyclopentadiene, etilidennorbornene, norbornenes, vinylcaprolactam, citraconic anhydride, N-phenylmaleimide, etc. Maleimides, vinyl ethers and the like can be mentioned. Two or more of these monomers may be used. The other monomer is preferably styrene.

The glass transition temperature (Tg) of the (meth) acrylic resin contained in the transfer layer is preferably 40 ° C. or higher, more preferably 80 ° C. or higher. Thereby, the thermoplastic resistance can be further improved.
The Tg of the (meth) acrylic resin contained in the transfer layer may be 150 ° C. or lower.
In the present disclosure, Tg is a value obtained by DSC (differential scanning calorimetry) in accordance with JIS K 7121: 2012.

The weight average molecular weight (Mw) of the (meth) acrylic resin contained in the transfer layer is preferably 10,000 or more and 100,000 or less, and more preferably 20,000 or more and 90,000 or less.
In the present disclosure, Mw means a value measured by gel permeation chromatography using polystyrene as a standard substance, and is measured in accordance with JIS K 7252-1: 2008.

The content of the (meth) acrylic resin contained in the transfer layer is preferably 20% by mass or more and 80% by mass or less, more preferably 40% by mass or more and 80% by mass or less, and 50% by mass, based on the total solid content of the transfer layer. % Or more and 75% by mass or less are more preferable, and 55% by mass or more and 65% by mass or less are particularly preferable.
By setting the content of the (meth) acrylic resin to 20% by mass or more, the thermoplastic resistance, glossiness and back-suppressing property can be further improved.
By setting the content of the (meth) acrylic resin to 80% by mass or less, the adhesiveness and transferability can be further improved.

Examples of the vinyl chloride-vinyl acetate copolymer contained in the transfer layer include a copolymer of vinyl chloride and vinyl acetate or a derivative thereof, and a copolymer of vinyl chloride, vinyl acetate and other monomers. Be done.
In the vinyl chloride-vinyl acetate copolymer, examples of the other monomer include the above-mentioned monomers.

The Tg of the vinyl chloride-vinyl acetate copolymer contained in the transfer layer is preferably 20 ° C. or higher and 100 ° C. or lower, and more preferably 50 ° C. or higher and 80 ° C. or lower.

The number average molecular weight (Mn) of the vinyl chloride-vinyl acetate copolymer contained in the transfer layer is preferably 5000 or more and 100,000 or less, and more preferably 10,000 or more and 80,000 or less.
In the present disclosure, Mn means a value measured by gel permeation chromatography using polystyrene as a standard substance, and is measured in accordance with JIS-K-7252-1: 2008.

The content of the vinyl chloride-vinyl acetate copolymer contained in the transfer layer is preferably 5% by mass or more and 65% by mass or less, and more preferably 5% by mass or more and 50% by mass or less, based on the total solid content of the transfer layer. , 15% by mass or more and 40% by mass or less is more preferable, and 20% by mass or more and 30% by mass or less is particularly preferable.
By setting the content of the vinyl chloride-vinyl acetate copolymer to 5% by mass or more, the adhesiveness and transferability can be improved.
By setting the content of the vinyl chloride-vinyl acetate copolymer to 65% by mass or less, the thermoplastic resistance, glossiness and back-suppressing property can be further improved.

In the transfer layer, the ratio of the (meth) acrylic resin to the vinyl chloride-vinyl acetate copolymer ((meth) acrylic resin / vinyl chloride-vinyl acetate copolymer) is preferably 0.3 or more and 10 or less on a mass basis. , 1.1 or more and 8 or less is more preferable, and 1.7 or more and 3.5 or less is further preferable. Thereby, the adhesiveness, the thermoplastic resistance, the glossiness, the transferability and the back suppressing property can be further improved.

The transfer layer preferably contains particles. Thereby, the scratch resistance (hereinafter, also simply referred to as “scratch resistance”) of the transfer layer in the printed matter can be improved.
Examples of the particles include organic particles and inorganic particles. Further, the particles may be powder or sol. Inorganic particles are preferable because the particles have high hardness and can improve scratch resistance.

Examples of the inorganic particles include clay minerals such as talc and kaolin, carbonates such as calcium carbonate and magnesium carbonate, hydroxides such as aluminum hydroxide and magnesium hydroxide, sulfates such as calcium sulfate, and silica. Inorganic particles such as oxides, graphite, sulfates, and boron nitride can be mentioned. As the inorganic particles, talc is preferable.

Examples of the organic particles include organic resin particles made of Teflon (registered trademark) resin, silicone resin, lauroyl resin, phenol resin, acetal resin, styrene resin, polyamide and the like, or crosslinked resin particles obtained by reacting these with a crosslinking material. Be done.

The average particle size (D50) of the particles contained in the transfer layer is preferably 0.1 μm or more and 20 μm or less, and more preferably 1 μm or more and 10 μm or less. This makes it possible to further improve the scratch resistance while maintaining the transparency of the transfer layer.
In the present disclosure, the average particle size of the particles can be measured by laser diffraction according to JIS Z 8825-1: 2013.

The content of the particles contained in the transfer layer is preferably 0.1% by mass or more and 2% by mass or less, and more preferably 0.3% by mass or more and 1% by mass or less with respect to the total solid content of the transfer layer. This makes it possible to further improve the scratch resistance while maintaining the transparency of the transfer layer.

The transfer layer preferably contains an ultraviolet absorber. This makes it possible to improve the light resistance of the printed matter. Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, and a triazine ultraviolet absorber. Two or more kinds of these ultraviolet absorbers may be used.

The content of the ultraviolet absorber contained in the transfer layer is preferably 1% by mass or more and 15% by mass or less, and more preferably 5% by mass or more and 10% by mass or less, based on the total solid content of the transfer layer.
By setting the content of the ultraviolet absorber to 1% by mass or more, the light resistance can be further improved.
By setting the content of the ultraviolet absorber to 15% by mass or less, the thermoplastic resistance can be further improved.

The transfer layer is a filler, an ultraviolet stabilizing material, a coloring inhibitor, a fluorescent whitening material, a matte material, a deodorant material, a flame retardant material, a weatherproof material, an antistatic material, a friction reducing material, a slip material, and an antioxidant material. , Ion exchangers, dispersants, polymerization initiators and additives such as colorants such as pigments and dyes may be included.

The thickness of the transfer layer is preferably 0.3 μm or more and 5 μm or less, and more preferably 0.5 μm or more and 1.5 μm or less.

The transfer layer is formed by dispersing or dissolving the above-mentioned material in water or an appropriate solvent, and using known means such as a roll coating method, a reverse roll coating method, a gravure coating method, a reverse gravure coating method, a bar coating method and a rod coating method. It can be formed by applying it on a base material, a release layer, or the like to form a coating film, and drying the coating film.

<Base material>
As the base material, a film made of a resin material (hereinafter, simply referred to as "resin film") can be used. Examples of the resin material include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene methylene terephthalate, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer. Polyethylene such as polyester, nylon 6 and polyamide such as nylon 6,6, polyethylene (PE), polypropylene (PP) and polyolefins such as polymethylpentene, polyvinyl chloride, polyvinyl alcohol (PVA), polyvinyl acetate, vinyl chloride-acetic acid. Vinyl copolymers, ethylene-vinyl acetate copolymers, vinyl resins such as polyvinyl butyral and polyvinylpyrrolidone (PVP), (meth) acrylic resins such as polyacrylates, polymethacrylates and polymethylmethacrylates, polyimides and polyetherimides. Iimide resin such as cellophane, cellulose acetate, nitrocellulose, cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB), styrene resin such as polystyrene (PS), polycarbonate, ionomer resin and the like. A film made of a resin material (hereinafter, simply referred to as "resin film") can be used.
Among the above-mentioned resins, polyesters such as PET and PEN are preferable, and PET is particularly preferable, from the viewpoint of heat resistance, mechanical strength, and transferability.

The above-mentioned laminate of resin films can also be used as a base material. The laminate of the resin film can be produced by using a dry lamination method, a wet lamination method, an extraction method, or the like.

When the base material is a resin film, the resin film may be a stretched film or an unstretched film, but from the viewpoint of strength, the stretched film stretched in the uniaxial direction or the biaxial direction is used. preferable.

The thickness of the base material is preferably 2 μm or more and 25 μm or less, and more preferably 3 μm or more and 16 μm or less. This makes it possible to improve the mechanical strength of the base material and the transfer of thermal energy during thermal transfer.

<Release layer>
The release layer is a layer that stays on the substrate during thermal transfer of the thermal transfer sheet. By providing the thermal transfer sheet with a release layer, transferability can be further improved.

The release layer contains at least one resin material. Examples of the resin material contained in the release layer include (meth) acrylic resin, polyurethane, acetal resin, polyamide, polyester, melamine resin, polyol resin, cellulose resin, silicone resin and the like.

The release layer may contain at least one release material. Examples of the release material include waxes such as fluorine compounds, phosphoric acid ester compounds, silicone oils and higher fatty acid amide compounds, metal soaps and paraffin waxes.

The content of the release material in the release layer is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less. Thereby, the transferability of the thermal transfer sheet can be further improved.

The release layer may contain the above additives.

The thickness of the release layer is, for example, 0.1 μm or more and 2.0 μm or less.

The release layer is prepared by dispersing or dissolving the above-mentioned material in an appropriate solvent to prepare a coating liquid, and applying the above-mentioned coating means on a base material or the like to form a coating film, which is dried. Can be formed by

<Color material layer>
The color material layer is a layer used to form an image. The colorant layer is a sublimation transfer type layer and contains at least one sublimation dye. Examples of sublimative dyes include diarylmethane dyes, triarylmethane dyes, thiazole dyes, merocyanine dyes, pyrazolone dyes, methine dyes, indian aniline dyes, acetophenone azomethine dyes, pyrazoloazomethine dyes, xanthene dyes, oxadin dyes, and thiazine dyes. , Azine dyes, acridin dyes, azo dyes, spiropyran dyes, indolinospiropiran dyes, fluorane dyes, naphthoquinone dyes, anthraquinone dyes, quinophthalone dyes and the like.

The color material layer contains at least one resin material. Examples of the resin material contained in the coloring material layer include polyester, polyamide, polyolefin, vinyl resin, (meth) acrylic resin, cellulose resin, styrene resin, polycarbonate, phenoxy resin, ionomer resin, acetal resin and the like.

The coloring material layer may contain the above-mentioned additive.

The thickness of the color material layer is, for example, 0.1 μm or more and 3 μm or less.

For the coloring material layer, the above-mentioned material is dispersed or dissolved in an appropriate solvent to prepare a coating liquid, and the above-mentioned coating means is applied onto a base material, a primer layer or the like to form a coating film, which is then applied. It can be formed by drying.

<Primer layer>
The primer layer is a layer that stays on the substrate during thermal transfer of the thermal transfer sheet. By providing the thermal transfer sheet with a primer layer, the adhesion between the base material and the coloring material layer can be improved.

The primer layer contains at least one resin material. Examples of the resin material contained in the primer layer include polyester, vinyl resin, polyurethane, (meth) acrylic resin, polyamide, polyether, styrene resin and cellulose resin.

The primer layer may contain the above-mentioned additive.

The thickness of the primer layer is, for example, 0.05 μm or more and 2.0 μm or less.

The primer layer is formed by dispersing or dissolving the above-mentioned material in an appropriate solvent to prepare a coating liquid, applying the above-mentioned coating means on a substrate or the like to form a coating film, and drying the coating film. Can be formed.

<Back layer>
The back layer is a layer of the base material provided on the side opposite to the side on which the transfer layer is provided. By providing the back layer of the thermal transfer sheet, it is possible to prevent sticking and wrinkles due to heating during thermal transfer.

The back layer may contain at least one resin material. Examples of the resin material contained in the back layer include vinyl resin, polyester, polyamide, polyolefin, (meth) acrylic resin, polyolefin, polyurethane, cellulose resin, phenol resin and the like.

The back layer may contain at least one isocyanate compound. Examples of the isocyanate composition contained in the back layer include xylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate and the like.

The back layer may contain the above additives.

The thickness of the back layer is, for example, 0.01 μm or more and 3.0 μm or less.

The back layer is formed by dispersing or dissolving the above-mentioned material in an appropriate solvent to prepare a coating liquid, applying the above-mentioned coating means on a base material to form a coating film, and drying the coating film. can.

The following is an embodiment of the thermal transfer sheet disclosed in the present disclosure. The thermal transfer sheet of the present disclosure is not limited to these embodiments.

The present disclosure is a thermal transfer sheet comprising a substrate and a transfer layer removably provided on one surface side of the substrate.
The transfer layer is a thermal transfer sheet which is a single layer containing a (meth) acrylic resin and a vinyl chloride-vinyl acetate copolymer.

In one embodiment, the transfer layer may be laminated directly on the substrate.

In one embodiment, a release layer may be provided between the substrate and the transfer layer.

In one embodiment, the ratio of the (meth) acrylic resin to the vinyl chloride-vinyl acetate copolymer may be 1.1 or more and 8 or less on a mass basis.

In one embodiment, the transfer layer may further contain particles.

In one embodiment, the glass transition temperature of the (meth) acrylic resin may be 80 ° C. or higher.

In one embodiment, the thermal transfer sheet may further include a colorant layer so as to be surface-sequential to the transfer layer.

In one embodiment, the thermal transfer sheet may be used for a transfer subject comprising a receiving layer containing a vinyl chloride-vinyl acetate copolymer.

The present disclosure will be described in more detail with reference to the following examples, but the present disclosure is not limited to these examples. Hereinafter, the content of the material for which the solid content ratio is written is shown before the solid content conversion.

In Examples and Comparative Examples, the (meth) acrylic resin and the vinyl chloride-vinyl acetate copolymer used are those shown in Table 1.

[Example 1]
As a base material, a polyethylene terephthalate (PET) film having a thickness of 4.5 μm (manufactured by Mitsubishi Chemical Corporation, Diafoil (registered trademark) K880-4.5W) was prepared.
A coating liquid for a back layer having the following composition was applied to one surface of the substrate and dried to form a back layer having a thickness of 0.1 μm.
Next, the coating liquids A to C for the coloring material layer having the following composition were applied to a part of the surface of the base material opposite to the back surface layer, dried, and the coloring material layers A to C having a thickness of 0.5 μm were obtained. Formed.
Next, a coating liquid for a transfer layer having the following composition was applied and dried so as to be surface-sequential to the color material layer to form a transfer layer having a thickness of 0.8 μm, and a thermal transfer sheet was obtained.

<Coating liquid for back layer>
-Polyvinyl butyral 2 parts by mass (Sekisui Chemical Co., Ltd., Eslek (registered trademark) BX-1)
-Polyisocyanate 9.2 parts by mass (manufactured by DIC Corporation, Barnock (registered trademark) D750)
1.3 parts by mass of phosphoric acid ester surfactant (Plysurf (registered trademark) A208N, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)
-Talc 0.3 parts by mass (manufactured by Nippon Talc Industry Co., Ltd., Micro Ace (registered trademark) P-3)
・ Methyl ethyl ketone (MEK) 43.6 parts by mass ・ Toluene 43.6 parts by mass

<Coating liquid A for color material layer>
・ Solvent Yellow 93 2 parts by mass ・ Disperse Yellow 231 2 parts by mass ・ Polyvinyl acetal 3.5 parts by mass (Sekisui Chemical Co., Ltd., Eslek (registered trademark) KS-5)
・ Polyethylene wax 0.1 parts by mass ・ MEK 45 parts by mass ・ Toluene 45 parts by mass

<Coating liquid B for color material layer>
・ Disperse dye (MS Red G) 1.5 parts by mass ・ Dispersion dye (Macrolex Red Violet R) 2 parts by mass ・ Polyvinyl acetal 4.5 parts by mass (Sekisui Chemical Co., Ltd., Eslek (registered trademark) KS- 5)
・ Polyethylene wax 0.1 parts by mass ・ MEK 45 parts by mass ・ Toluene 45 parts by mass

<Coating liquid C for color material layer>
・ Solvent Blue 63 2 parts by mass ・ Disperse Blue 354 2 parts by mass ・ Polyvinyl acetal 3.5 parts by mass (Sekisui Chemical Co., Ltd., Eslek (registered trademark) KS-5)

<Composition of coating liquid for transfer layer>
(Meta) Acrylic resin A 30 parts by mass-Vinyl chloride-vinyl acetate copolymer A 70 parts by mass-Tark 0.82 parts by mass (Made by Nippon Tarku Kogyo Co., Ltd., Micro Ace (registered trademark) P-3)
-Dispersant 0.12 parts by mass (manufactured by Big Chemie Japan Co., Ltd., BYK-180)
・ UV absorber 10.0 parts by mass (benzotriazole UV absorber, manufactured by Sun Chemical Co., Ltd., UV-329)
-Phosphoric acid ester surfactant 5.3 parts by mass (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Plysurf (registered trademark) A208N)
・ MEK 117 parts by mass ・ Propyl acetate 50 parts by mass

[Examples 2 to 14, Comparative Examples 1 to 2]
A thermal transfer sheet was prepared in the same manner as in Example 1 except that the composition of the transfer layer was changed as shown in Table 2.

[Example 15]
Example 4 and Example 4 except that a release layer coating liquid having the following composition was applied to the substrate and dried to form a release layer having a thickness of 0.1 μm between the substrate and the transfer layer. A thermal transfer sheet was obtained in the same manner.
<Coating liquid for mold release layer>
10 parts by mass of acrylic silicone graft polymer (manufactured by Toagosei Co., Ltd., Cymac (registered trademark) US350)
・ MEK 20 parts by mass ・ Toluene 20 parts by mass

[Comparative Example 3]
A thermal transfer sheet was obtained in the same manner as in Example 1 except that the transfer layer was formed as follows.
A coating liquid for a protective layer having the following composition was applied and dried so as to be surface-sequential to the color material layer to form a protective layer having a thickness of 0.8 μm.
Next, a coating liquid for an adhesive layer having the following composition was applied onto the protective layer and dried to form an adhesive layer having a thickness of 0.8 μm to obtain a thermal transfer sheet.
The protective layer and the adhesive layer of the thermal transfer sheet correspond to the transfer layer.
<Coating liquid for protective layer>
(Meta) Acrylic resin A 30 parts by mass-Vinyl chloride-vinyl acetate copolymer A 70 parts by mass-Tark 0.82 parts by mass (Made by Nippon Tarku Kogyo Co., Ltd., Micro Ace (registered trademark) P-3)
-Dispersant 0.12 parts by mass (manufactured by Big Chemie Japan Co., Ltd., BYK-180)
-Phosphoric acid ester surfactant 5.3 parts by mass (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Plysurf (registered trademark) A208N)
・ MEK 117 parts by mass ・ Propyl acetate 50 parts by mass <Coating liquid for adhesive layer>
100 parts by mass of polyester (manufactured by Toyobo Co., Ltd., Byron (registered trademark) 700)
・ 10 parts by mass of copolymer reaction-bonded with UV absorber (UVA-635L, manufactured by BASF Japan Ltd.)
・ MEK 220 parts by mass ・ Toluene 220 parts by mass

[Comparative Example 4]
A thermal transfer sheet was prepared in the same manner as in Comparative Example 3 except that the composition of the transfer layer was changed as shown in Table 2.

<< Adhesiveness evaluation >>
On a genuine image receiving paper for DS620, a printer manufactured by Dai Nippon Printing Co., Ltd., the transfer layer of the thermal transfer sheet has a gradation of 0 to 255 using the following evaluation printers and the thermal transfer sheets produced in Examples and Comparative Examples. The image was printed with the gradation pattern of the gradation image of.
[Evaluation printer]
・ Thermal head: F3598 (manufactured by Toshiba Hokuto Electronics Corporation)
-Average resistance value of heating element: 5015 (Ω)
-Main scanning direction printing density: 300 (dpi)
-Printing density in the sub-scanning direction: 300 (dpi)
-Applied voltage: 19.0 (V)
-Line cycle: 2 (msec./line)
-Pulse Duty: 85%

After that, a mending tape is attached on the transferred transfer layer, and the state of the tape and the printed matter when the tape is peeled off at a peeling angle of 90 ° is visually confirmed, and the adhesiveness is based on the following evaluation criteria. Was evaluated. The evaluation results are shown in Table 2.
In the following evaluation criteria, "the transfer layer is adhered" means that the transfer layer was not peeled off by the mending tape.
Further, in the following evaluation criteria, "image gradation" is an index different from the energy gradation of the heating energy by the thermal head. As the gradation value of the image gradation decreases, the energy gradation increases. Therefore, "0/255 image gradation" is a transfer with high energy.
〔Evaluation criteria〕
A: The transfer layer is adhered to the image receiving paper at the portion of the image gradation from 0 to 120/255.
B: The transfer layer is adhered to the image receiving paper at the portion of the image gradation from 0 to 90/255.
C: The transfer layer is adhered to the image receiving paper in the portion of the image gradation of 0 to 60/255. D: The transfer layer is adhered to the image receiving paper in the portion of the image gradation of 0 to 30/255.
NG: The transfer layer is adhered to the image receiving paper only in the portion of 0/255 image gradation.

<< Evaluation of thermoplastic resistance >>
The thermal transfer sheets produced in the above Examples and Comparative Examples, a sublimation type thermal transfer printer (DS620 manufactured by Dai Nippon Printing Co., Ltd.), and a genuine image receiving paper for the printer were prepared. In a 20 ° C. and 30% RH environment, the sublimation dye is transferred from the thermal transfer sheet onto the receiving layer provided on the image receiving paper to form a solid black image (0/255 gradation (image gradation)), and the transfer layer is formed. , Formed in gross mode to obtain imprints.
A soft vinyl chloride (PVC) sheet containing a plastic material (Altron # 480, thickness 400 μm, manufactured by Mitsubishi Chemical Corporation) is layered on the transfer surface of the transfer layer of the printed material, and a weight of 1 kg is placed on it under a 50 ° C environment. Stored for 24 hours. After the PVC sheet was peeled off, the deterioration state of the image of the printed matter due to the plastic material was visually observed, and the plastic material resistance was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 2.
〔Evaluation criteria〕
A: The image of the printed matter is not taken on the PVC sheet at all.
B: The image of the printed matter has been transferred to the PVC sheet, but the minute-sized image is only slightly taken on the PVC sheet and is hardly noticeable.
C: The image of the printed matter has been transferred to the PVC sheet, but only a small-sized image was partially taken on the PVC sheet, which is good as a product.
D: The image of the printed matter is completely transferred to the PVC sheet, but the image is only slightly taken on the PVC sheet, and there is no problem as a product.
NG: The image of the printed matter is completely transferred to the PVC sheet, and the image is completely taken on the PVC sheet, which causes a problem as a product.

<< Evaluation of high energy transferability >>
The thermal transfer sheets produced in the above Examples and Comparative Examples, a sublimation thermal transfer printer (DS620 manufactured by Dai Nippon Printing Co., Ltd.), and a genuine image receiving paper for the printer were prepared. In a 20 ° C. and 30% RH environment, only the transfer layer (without transferring the sublimation dye) was formed from the thermal transfer sheet on the receiving layer provided on the image receiving paper in the mat mode to obtain a printed matter.
The obtained printed matter was visually observed, and the high energy transferability was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 2.
〔Evaluation criteria〕
A: There was no location where the transfer layer was not transferred, and good high-energy transferability was confirmed over the entire transfer region.
NG: The transfer layer was not peeled off from the ink ribbon and was not transferred (NG1), or a part of the transfer layer was not peeled off from the ink ribbon and there was a part that was not transferred (NG2).

<< Glossy evaluation >>
A printed matter was obtained in the same manner as in the above-mentioned evaluation of thermoplastic resistance.
The obtained printed matter was measured at a reflection angle of 20 ° using Gloss Meter VG7000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.), and the glossiness was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 2.
〔Evaluation criteria〕
A: It was confirmed that the printed matter had an extremely high glossiness.
B: It was confirmed that the printed matter had a high glossiness.
C: The glossiness of the printed matter could be confirmed.
D: The glossiness of the printed matter was slightly insufficient.
NG: The glossiness of the printed matter was insufficient.

<< Transcription evaluation >>
A printed matter was obtained in the same manner as in the above adhesiveness evaluation except that the applied voltage was set to 17.0 V.
The state of the obtained printed matter was visually confirmed, and the transferability was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 2.
〔Evaluation criteria〕
A: The transfer layer is transferred to the image receiving paper at the portion of the image gradation from 0 to 120/255.
B: The transfer layer is transferred to the image receiving paper at the portion of the image gradation from 0 to 90/255.
C: The transfer layer is transferred to the image receiving paper in the portion of the image gradation of 0 to 60/255. D: The transfer layer is transferred to the image receiving paper in the portion of the image gradation of 0 to 30/255.
NG: The transfer layer is transferred to the image receiving paper only in the portion of 0/255 image gradation.

<< Back suppression evaluation >>
The back layer of the thermal transfer sheet produced in the above Examples and Comparative Examples was opposed to the magenta dye layer, a load of 1.96 MPa was applied, and the magenta dye was stored in a 40 ° C. 90% RT environment for 96 hours, and the magenta dye was placed on the back layer side. The magenta dye in the layer was transferred (kicked). This back layer is opposed to the transfer layer surface of the thermal transfer sheet produced in Examples and Comparative Examples, a load of 1.96 MPa is applied, and the mixture is stored in a 50 ° C. 20% RT environment for 24 hours, and the back surface is on the transfer layer side. The magenta dye in the layer was transferred (backed). After that, the transfer layer surface and the image receiving surface of the genuine image receiving paper for DS620 were overlapped, and a laminating tester (Lamipacker LPD2305PRO, manufactured by Fujipla Co., Ltd.) was used at 110 ° C., 1.0 m / min. Transcription was performed at. After peeling off the PET film of the thermal transfer sheet, the degree of coloring of the transfer layer was visually confirmed, and the back inhibitory property was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 2.
〔Evaluation criteria〕
A: Not visible at all.
B: If you are careful, you can see it slightly.
C: It looks faint, but there is no problem.
D: I can see it.
NG: I can see it clearly.

<< Scratch resistance evaluation >>
A printed matter was obtained in the same manner as in the above-mentioned evaluation of thermoplastic resistance.
The image receiving surface side of the obtained printed matter was superposed on the white cloth attached to the test (cotton, Kanakin No. 3), and a load of 10 g / cm ² was applied to perform a reciprocating friction test 50 times. The state of the image formed on the printed matter was visually confirmed, and the scratch resistance was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 2.
〔Evaluation criteria〕
A: The image is not affected at all.
B: The image is starting to be slightly affected by friction, but it is not noticeable at all.
C: The image is slightly affected by friction, but it is hardly noticeable.
D: The image is affected by friction, but it is not noticeable.
NG: It is considerably worn and there is a problem in use.

<< Light resistance evaluation >>
The thermal transfer sheets produced in the above Examples and Comparative Examples, a sublimation thermal transfer printer (DS620 manufactured by Dai Nippon Printing Co., Ltd.), and a genuine image receiving paper for the printer were prepared. In a 20 ° C. and 30% RH environment, the sublimation dye is transferred from the thermal transfer sheet onto the receiving layer provided on the image receiving paper, the transfer layer is transferred, and a black step image is formed in gloss mode to produce a printed matter. Obtained. The obtained printed matter was irradiated with a lamp under the conditions of the light resistance test shown below.
[Conditions for light resistance test]
-Irradiation tester: Ci4000 manufactured by Atlas
-Light source: Xenon lamp (6.5 kW)
・ Filter: Inside = CIRA
Outside = soda lime black panel temperature: 45 (℃)
・ Irradiation intensity: 1.2 (W / m2) ・ ・ ・ Measured value at 420 (nm) ・ Irradiation energy: 400 (kJ / m2) ・ ・ ・ Integrated value at 420 (nm)

Under the conditions of the above light resistance test, the change in the optical reflection density before and after the lamp irradiation is measured by an optical densitometer (Spectrolino X-Rite), and the concentration residual rate is measured in the step where the optical reflection density before irradiation is close to 1.0. Was calculated by the following formula.
Concentration residual rate = {(optical density after irradiation) / (optical density before irradiation)} x 100

The light resistance was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 2.
〔Evaluation criteria〕
A: The residual concentration rate is 90% or more.
B: The residual concentration rate is 85% or more and less than 90%.
C: The residual concentration rate is 80% or more and less than 85%.
D: The residual concentration rate is 75% or more and less than 80%.
NG: The residual concentration is less than 75%.

10: Thermal transfer sheet, 11: Substrate, 12: Transfer layer, 13: Release layer, 14: Color material layer

Claims (8)

A thermal transfer sheet including a base material and a transfer layer provided on one surface side of the base material so as to be peelable.
The transfer layer is a thermal transfer sheet which is a single layer containing a (meth) acrylic resin and a vinyl chloride-vinyl acetate copolymer. The thermal transfer sheet according to claim 1, wherein the transfer layer is directly laminated on the substrate. The thermal transfer sheet according to claim 1, wherein a release layer is provided between the base material and the transfer layer. The thermal transfer sheet according to any one of claims 1 to 3, wherein the ratio of the (meth) acrylic resin to the vinyl chloride-vinyl acetate copolymer is 1.1 or more and 8 or less on a mass basis. The thermal transfer sheet according to any one of claims 1 to 4, wherein the transfer layer further contains particles. The thermal transfer sheet according to any one of claims 1 to 5, wherein the (meth) acrylic resin has a glass transition temperature of 80 ° C. or higher. The thermal transfer sheet according to any one of claims 1 to 6, further comprising a coloring material layer so as to be surface-sequential to the transfer layer. The thermal transfer sheet according to any one of claims 1 to 7, which is used for a transfer subject including a receiving layer containing a vinyl chloride-vinyl acetate copolymer.

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