JP2020049690A - Thermal transfer sheet - Google Patents

Abstract

To provide a thermal transfer sheet having a high printing wrinkle prevention, transferability and blocking resistance.SOLUTION: A thermal transfer sheet 10 includes a back surface layer 11 containing a (meth)acrylic resin, a base material 12, a release layer 13 containing polyester and a transfer layer 14, in which the transfer layer 14 includes at least a release layer 15 adjacent to the release layer 13, and a content of the polyester with respect to 100 pts.mass of the total amount of a resin material contained in the release layer 13 is 50 pts.mass or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermal transfer sheet.

Conventionally, energy is applied to a thermal transfer sheet including a back layer, a base material, and a transfer layer using a thermal head or the like, and the transfer layer is transferred onto a transfer target conveyed in a printer. There is known a hot-melt transfer system in which an image is formed by forming an image.
Since an image formed by the hot-melt transfer method has high density and excellent sharpness, this method is suitable for recording binary images such as characters and line drawings. In addition, according to the thermal fusion transfer method, variable information such as an address, customer information, numbering, and a barcode can be recorded on a transfer target using a computer and a thermal transfer printer.

  Normally, such a thermal transfer sheet is required to have high transferability so that a good image free of dropouts and blurring can be formed.

Conventionally, for the purpose of improving transferability, a release layer containing wax or the like is provided as a layer constituting a transfer layer (Patent Document 1).
The release layer is melted by energy applied during transfer, and the transfer improves the transferability of the transfer layer.

In the conventional thermal transfer sheet as described above, at the time of transfer of the transfer layer, the shear force of the transferred transfer object is applied to the melted release layer, and transfer is not performed normally. As a result of a shift between the transfer expected position of the layer and the actual transfer position, wrinkles (hereinafter referred to as print wrinkles) are generated in the printed matter, and the quality is remarkably impaired.
The print wrinkles are particularly problematic when the substrate is stretched or distorted due to energy applied during transfer.

  Further, as the thermal transfer sheet, those further provided with a release layer between the substrate and the release layer are known, and according to the thermal transfer sheet having such a configuration, the occurrence of the print wrinkles can be reduced to some extent. Depending on the configuration, the transferability may not be sufficient, for example, the transferability may not be transferred, or the printed matter may be missing or blurred.

  Further, the thermal transfer sheet is usually wound up and stored, but during storage, an abnormal transfer (so-called blocking) in which the transfer layer is transferred onto the back layer may occur. It is required to have blocking resistance.

JP-A-2005-128877

  The present invention has been made in view of the above problems, and a problem to be solved is to provide a thermal transfer sheet having high print wrinkle prevention, transferability, and blocking resistance.

The thermal transfer sheet of the present invention includes a back layer containing (meth) acrylic resin, a base material, a release layer containing polyester, and a transfer layer,
The transfer layer includes at least a release layer adjacent to the release layer,
The polyester content is at least 50 parts by mass based on 100 parts by mass of the total amount of the resin material contained in the release layer.

  In one embodiment, the content of the polyester in the release layer is from 20% by mass to 100% by mass.

  In one embodiment, the release layer further includes a filler.

  In one embodiment, the content of the filler in the release layer is from 20% by mass to 80% by mass.

  In one embodiment, the thickness of the release layer is 0.05 μm or more and 0.8 μm or less.

  In one embodiment, the thickness of the back layer is 0.2 μm or more and 0.5 μm or less.

  ADVANTAGE OF THE INVENTION According to this invention, the thermal transfer sheet which has high printing wrinkle prevention property, transferability, and blocking resistance can be provided.

FIG. 1 is a schematic sectional view illustrating an embodiment of a thermal transfer sheet of the present invention. FIG. 1 is a schematic sectional view illustrating an embodiment of a thermal transfer sheet of the present invention. FIG. 1 is a schematic sectional view illustrating an embodiment of a thermal transfer sheet of the present invention. It is a figure showing a Ladder barcode image formed in an example. It is a figure showing a Picket barcode image formed in an example.

(Thermal transfer sheet)
As shown in FIG. 1, the thermal transfer sheet 10 according to the present invention includes a back layer 11, a base material 12, a release layer 13, and a transfer layer 14, and the transfer layer 14 is adjacent to the release layer 13. At least a release layer 15 is provided. .
In one embodiment, the transfer layer 14 further includes a coloring layer 16 on the release layer 15 as shown in FIG.
In one embodiment, the transfer layer 14 further includes an adhesive layer 17 on the colored layer 16 as shown in FIG.
Hereinafter, each layer included in the thermal transfer sheet according to the present invention will be described.

(Back layer)
The thermal transfer sheet of the present invention has a back layer containing a (meth) acrylic resin on the surface of the substrate on which the transfer layer is not provided. When the thermal transfer sheet is provided with such a back surface layer, the anti-wrinkle property, transferability and blocking resistance of the thermal transfer sheet can be remarkably improved.

In the present invention, the (meth) acrylic resin includes:
(1) a polymer of a monomer of (meth) acrylic acid or a derivative thereof,
(2) a polymer of a (meth) acrylate monomer or a derivative thereof,
(3) A copolymer of a (meth) acrylic acid monomer and another monomer or a derivative thereof, and (4) a copolymer of a (meth) acrylic acid ester monomer and another monomer or a derivative thereof are included. .
In the present invention, “(meth) acryl” includes both “acryl” and “methacryl”. Further, “(meth) acrylate” includes both “acrylate” and “methacrylate”.

Examples of (meth) acrylate monomers include alkyl acrylate, alkyl methacrylate, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, lauryl acrylate, and lauryl methacrylate.
Other monomers are not particularly limited, for example, aromatic hydrocarbons, aryl group-containing compounds, amide group-containing compounds, vinyl chloride, and more specifically, styrene, benzylstyrene, phenoxyethyl methacrylate, ( (Meth) acrylamide and the like.

More specifically, examples of the (meth) acrylic resin include poly (meth) acrylate, polymethyl (meth) acrylate, and styrene acrylic copolymer.
Among these, polymethyl (meth) acrylate is particularly preferred from the viewpoints of anti-wrinkle properties, transferability and blocking resistance.

  The content of the (meth) acrylic resin in the back layer is preferably 40% by mass or more and 100% by mass or less, and more preferably 50% by mass or more and 90% by mass or less. Thereby, the print wrinkle prevention property and the blocking resistance of the thermal transfer sheet can be further improved.

Also, in one embodiment, the back layer may include one or more of the above fillers. Thereby, the blocking resistance of the thermal transfer sheet can be further improved.
The filler is not particularly limited, and may be an organic filler or an inorganic filler.
Examples of the organic filler include particles made of a resin material such as a melamine resin, an epoxy resin, an imide resin, a polyamide, a polyolefin resin, and a (meth) acrylic resin.
As the inorganic filler, for example, calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc carbonate, magnesium carbonate, aluminum silicate, calcium silicate, magnesium silicate, silica, colloidal silica, colloidal alumina, water Examples include aluminum oxide, alumina, zeolite, and magnesium hydroxide.

  The content of the filler in the back layer is preferably 5% by mass or more and 20% by mass or less, and more preferably 8% by mass or more and 17% by mass or less. Thereby, the blocking resistance of the thermal transfer sheet can be further improved.

In one embodiment, the back layer contains a lubricant, which can further improve the blocking resistance of the thermal transfer sheet.
Examples of the lubricant include metal soap, polyethylene wax, paraffin wax, anionic surfactant, cationic surfactant, amphoteric surfactant and nonionic surfactant.

  The content of the lubricant in the back layer is preferably from 5% by mass to 40% by mass, more preferably from 10% by mass to 30% by mass. Thereby, the blocking resistance of the thermal transfer sheet can be further improved.

  As long as the properties of the present invention are not impaired, the back layer may contain a resin material other than the (meth) acrylic resin, for example, cellulose resin, styrene resin, vinyl resin, polyester, polyurethane, silicone-modified polyurethane, and fluorine-modified Polyurethane and the like.

  The back layer may contain additives such as a filler, a plasticizer, an antistatic material, an ultraviolet absorber, and a dispersant as long as the characteristics of the present invention are not impaired.

  The thickness of the back layer is preferably from 0.2 μm to 0.5 μm, and more preferably from 0.2 μm to 0.4 μm. Thereby, the anti-wrinkle property of the thermal transfer sheet, the transfer property, and the blocking resistance of the thermal transfer sheet can be further improved.

  The back layer is obtained by dispersing or dissolving the above material in water or a suitable solvent, and applying a known method 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 a film on a substrate to form a coating film and drying the coating film.

(Base material)
The substrate has heat resistance enough to withstand the heat energy applied at the time of thermal transfer, and can be used without particular limitation as long as it has mechanical strength and solvent resistance that can support a transfer layer and the like provided on the substrate. .

As the base material, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene dimethylene terephthalate, terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, etc. Polyester such as polyester, nylon 6 and nylon 6,6, polyolefin such as polyethylene (PE), polypropylene (PP) and polymethylpentene, polyvinyl chloride, polyvinyl alcohol (PVA), polyvinyl acetate, vinyl chloride-vinyl acetate Copolymers, vinyl resins such as polyvinyl butyral and polyvinyl pyrrolidone (PVP), (meth) acrylic resins, imide resins such as polyimide and polyetherimide, cellophane, cellulose acetate Nitrocellulose, cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) and other cellulose resins, polystyrene (PS) and other styrene resins, polycarbonates, ionomer resins and other films (hereinafter simply referred to as "Resin film") can be used.
Among the above-mentioned resins, polyesters such as PET and PEN are preferred from the viewpoint of heat resistance and mechanical strength, and PET is particularly preferred.

  Further, a laminate of the above resin films can be used as a substrate. The laminated body of the resin film can be manufactured by using a dry lamination method, a wet lamination method, an extrusion method, or the like.

  When the substrate is a resin film, the resin film may be a stretched film or an unstretched film, but from the viewpoint of strength, a stretched film stretched in a uniaxial or biaxial direction. It is preferred to use.

  The thickness of the substrate is preferably 2 μm or more and 25 μm or less, more preferably 3 μm or more and 10 μm or less. Thereby, the mechanical strength of the substrate can be improved. Further, the printing wrinkle prevention property and the transfer property of the thermal transfer sheet can be further improved.

(Release layer)
The release layer is a layer provided between the base material and the transfer layer, and stays on the base material side during the transfer of the transfer layer.

The release layer contains at least one kind of polyester, and its content is at least 50 parts by mass based on 100 parts by mass of the total amount of the resin material contained in the release layer. When the thermal transfer sheet of the present invention includes the release layer having such a configuration, the print wrinkle preventing property and the transfer property can be remarkably improved. Further, the alcohol resistance of the print can be improved.
Further, from the viewpoint of anti-wrinkle property of printing, transferability and alcohol resistance, the content of polyester relative to the total amount of 100 parts by mass of the resin material contained in the release layer is preferably 70 parts by mass or more, and more preferably 90 parts by mass. Parts or more is more preferable.

In the present invention, the polyester means a copolymer of a dicarboxylic acid compound and a diol compound.
Examples of the dicarboxylic acid compound include, for example, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, eicosandioic acid, pimelic acid, azelaic acid, methylmalonic acid and ethylmalonic acid, adamantane Dicarboxylic acid, norbornene dicarboxylic acid, cyclohexane dicarboxylic acid, decalin dicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1, 8-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, 5-sodium sulfoisophthalic acid, phenylendanedicarboxylic acid, anthracenedicarboxylic acid, phenanthenedicarboxylic acid, 9, '- bis (4-carboxyphenyl) fluorene acid and the like these ester derivatives.
Examples of the diol compound include ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol, and cyclohexane. Diethanol, decahydronaphthalenediethanol, decahydronaphthalenediethanol, norbornane dimethanol, norbornanediethanol, tricyclodecanedimethanol, tricyclodecaneethanol, tetracyclododecanedimethanol, tetracyclododecanediethanol, decalindimethanol, decalindiethanol, 5 -Methylol-5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -1,3-dioxane, cyclohexanediol, Cyclohexyl-4,4′-diol, 2,2-bis (4-hydroxycyclohexylpropane), 2,2-bis (4- (2-hydroxyethoxy) cyclohexyl) propane, cyclopentanediol, 3-methyl-1, 2-cyclopentadiol, 4-cyclopentene-1,3-diol, adamandiol, paraxylene glycol, bisphenol A, bisphenol S, styrene glycol, trimethylolpropane, pentaerythritol and the like.

  As long as the properties of the present invention are not impaired, the polyester may contain a monomer other than the dicarboxylic acid compound and the diol compound, but the content is preferably 10 mol% or less based on all the structural units. , More preferably 5 mol% or less, and even more preferably 3 mol% or less.

  The content of the polyester in the release layer is preferably from 20% by mass to 100% by mass, more preferably from 20% by mass to 80% by mass, and from 30% by mass to 70% by mass. Is particularly preferred. As a result, it is possible to further improve the anti-wrinkle property of the thermal transfer sheet, the transfer property, and the alcohol resistance of the print.

  In one embodiment, the release layer may include one or more of the above fillers. Thereby, the print wrinkle prevention property and the blocking resistance of the thermal transfer sheet can be further improved.

The average particle size of the filler is not particularly limited, and can be 0.1 μm or more and 4.0 μm or less.
In the present invention, the average particle diameter is measured by a laser method.

  The shape of the filler may be any of a spherical shape, an elliptical shape, a cylindrical shape, a prismatic shape, an amorphous shape, and the like.

  The content of the filler in the release layer is preferably 20% by mass or more and 80% by mass or less, and more preferably 30% by mass or more and 70% by mass or less. This makes it possible to further improve the anti-wrinkle property and the blocking resistance while maintaining the transferability of the thermal transfer sheet and the alcohol resistance of the print.

  The release layer may contain a resin material other than polyester as long as the properties of the present invention are not impaired. For example, polyamide, polyolefin, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, etc. Vinyl resin, (meth) acrylic resin, cellulose resin, styrene resin, ionomer resin and the like.

  The release layer may contain the above-mentioned additive as long as the properties of the present invention are not impaired.

  The thickness of the release layer is preferably 0.05 μm or more and 0.8 μm or less, and more preferably 0.1 μm or more and 0.5 μm or less. Thereby, the print wrinkle prevention property and the transfer property of the thermal transfer sheet can be further improved.

  The release layer is formed by dispersing or dissolving the above material in water or a suitable solvent, and applying a 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. Thus, it can be formed by applying a film on a base material to form a coating film and drying the coating film.

(Transfer layer)
The thermal transfer sheet of the present invention includes a transfer layer, and the transfer layer includes at least a release layer provided adjacent to the release layer.
In one embodiment, the transfer layer includes a coloring layer on the release layer.
In one embodiment, the transfer layer further includes an adhesive layer on the colored layer.

(Release layer)
In one embodiment, the release layer comprises one or more waxes, for example, natural waxes such as beeswax, spermaceti, wood wax, rice bran wax, carnauba wax, candelilla wax and montan wax, paraffin wax, micro wax. Synthetic waxes such as crystallin wax, oxidized wax, ozokerite, ceresin, ester wax and polyethylene wax, higher saturated fatty acids such as margaric acid, lauric acid, myristic acid, palmitic acid, stearic acid, freunic acid and behenic acid, stearyl alcohol and behenyl alcohol And higher esters such as fatty acid esters of sorbitan, and higher fatty acid amides such as stearamide and oleamide.

  The content of the wax in the release layer is not particularly limited, but may be, for example, 20% by mass or more and 100% by mass or less. Thereby, the transferability of the thermal transfer sheet can be further improved.

  In one embodiment, the release layer comprises one or more resin materials, for example, (meth) acrylic resin, cellulose resin, polyester, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer And the like.

  In addition, the release layer may contain the above-mentioned additive as long as the characteristics of the present invention are not impaired.

  The thickness of the release layer is preferably from 0.2 μm to 0.7 μm, more preferably from 0.3 μm to 0.7 μm. Thereby, the transferability of the thermal transfer sheet can be further improved.

  The release layer is obtained by dispersing or dissolving the above material in water or a suitable solvent, and applying a known method 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 a coating on a release layer to form a coating film and drying the coating film.

(Colored layer)
In one embodiment, the coloring layer includes one or more resin materials, such as polyester, polyamide, polyolefin, (meth) acrylic resin, cellulose resin, styrene resin, ethylene-vinyl acetate copolymer, and chloride. Examples include vinyl resins such as vinyl-vinyl acetate copolymers, and ionomer resins.

  The content of the resin material in the coloring layer is not particularly limited, but may be, for example, 50% by mass or more and 70% by mass or less.

  As the coloring material contained in the coloring layer, carbon black, an inorganic pigment, an organic pigment or a dye can be appropriately selected and used according to a required color tone or the like. For example, in the case of barcode printing, it is preferable to use a barcode having a particularly sufficient black density and not discoloring or fading due to light and heat. Examples of such a coloring material include carbon black such as lamp black, graphite, and nigrosine dye. When color printing is required, other chromatic dyes or pigments are used.

  The content of the coloring material in the coloring layer is not particularly limited, but may be, for example, 25% by mass or more and 45% by mass or less. Thereby, the density of the formed image can be improved.

  The colored layer may contain the above-mentioned additive within a range that does not impair the characteristics of the present invention.

  The thickness of the coloring layer is not particularly limited, but may be, for example, 0.3 μm or more and 1.2 μm or less.

  The colored layer is obtained by dispersing or dissolving the above material in water or a suitable solvent, and applying a known method 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 a coating film on a release layer to form a coating film and drying the coating film.

(Adhesive layer)
In one embodiment, the adhesive layer includes at least one type of thermoplastic resin that softens when heated and exhibits adhesion.
As the thermoplastic resin, for example, polyester, vinyl resin such as ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, (meth) acrylic resin, (meth) acrylic resin, polyurethane, cellulose resin, polyamide, Examples include polyolefin, styrene resin, and chlorinated resins thereof.

  The content of the thermoplastic resin in the adhesive layer is not particularly limited, but is, for example, preferably 50% by mass or more, and more preferably 60% by mass or more. Thereby, the adhesiveness of the adhesive layer to the transfer object can be improved.

  The adhesive layer may contain the above-mentioned additive within a range that does not impair the characteristics of the present invention.

  The thickness of the adhesive layer is not particularly limited, but may be, for example, 0.05 μm or more and 0.5 μm or less. Thereby, the adhesiveness of the adhesive layer to the transfer object can be improved.

  The adhesive layer is obtained by dispersing or dissolving the above material in water or a suitable solvent, and applying a known method 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 a coating on a colored layer to form a coating film and drying the coating film.

  Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1
On one surface of the PET film having a thickness of 4.5 μm, a coating solution for forming a release layer having the following composition was applied and dried to form a release layer having a thickness of 0.2 μm.
<Coating liquid for release layer formation>
-50 parts by mass of polyester (manufactured by Toyobo Co., Ltd., Byron (registered trademark) 200)
-150 parts by mass of toluene-150 parts by mass of methyl ethyl ketone (MEK)

On the release layer formed as described above, a coating dispersion for forming a release layer having the following composition was applied and dried to form a release layer having a thickness of 0.4 μm.
<Coating liquid for forming release layer>
・ 45 parts by mass of carnauba wax (WE-95, manufactured by Konishi Co., Ltd.)
・ Isopropanol (IPA) 150 mass parts ・ Water 50 mass parts

On the release layer formed as described above, a coating solution for forming a colored layer having the following composition was applied and dried to form a colored layer having a thickness of 0.7 μm.
<Coating solution for forming colored layer>
・ 33 parts by mass of carbon black ・ 67 parts by mass of polyester ・ 150 parts by mass of toluene ・ 150 parts by mass of methyl ethyl ketone (MEK)

On the colored layer formed as described above, a coating liquid for forming an adhesive layer having the following composition was applied and dried to form an adhesive layer having a thickness of 0.2 μm.
<Coating liquid for forming adhesive layer>
-50 parts by mass of polyester (manufactured by Toyobo Co., Ltd., Byron (registered trademark) GK250)
・ 200 parts by mass of methyl ethyl ketone (MEK)

On the other surface of the PET film, a coating solution for forming a back layer having the following composition was applied and dried to form a back layer having a thickness of 0.3 μm, thereby obtaining a thermal transfer sheet.
<Coating liquid for back layer formation>
-54 parts by weight of polymethyl methacrylate-1.5 parts by weight of linear saturated polyester-29.5 parts by weight of zinc stearyl phosphate-15 parts by weight of melamine resin powder-400 parts by weight of methyl ethyl ketone (MEK)

Examples 2 to 7
A thermal transfer sheet was produced in the same manner as in Example 1, except that the thickness of the release layer was changed as shown in Table 1.

Examples 8 to 13
A thermal transfer sheet was produced in the same manner as in Example 1, except that the composition of the release layer was changed as shown in Table 1.
As the inorganic filler A, silica (manufactured by Fuji Silysia Chemical Ltd., Sylysia 310P, average particle diameter 2.7 μm) is used. FG-15, average particle diameter 1.5 μm), as an organic filler, melamine resin powder (Nippon Shokubai Co., Ltd., Eposter S6, average particle diameter 0.4 μm), and as an ethylene-vinyl acetate copolymer, Evaflex (registered trademark) EV250 manufactured by Du Pont-Mitsui Polychemicals Co., Ltd. was used.

Comparative Example 1
A thermal transfer sheet was produced in the same manner as in Example 1 except that no release layer was provided.

Comparative Examples 2 to 4
A thermal transfer sheet was produced in the same manner as in Example 1, except that the composition of the release layer was changed as shown in Table 1.
As the ethylene-vinyl acetate copolymer, Evaflex (registered trademark) EV250 manufactured by DuPont-Mitsui Polychemicals Co., Ltd., and as the cellulose resin, manufactured by Eastman Chemical Japan Co., Ltd .; As the resin, Dianal (registered trademark) BR-87 manufactured by Mitsubishi Chemical Corporation was used.

Comparative Example 5
A thermal transfer sheet was prepared in the same manner as in Example 1, except that the coating liquid for forming the back layer used in forming the back layer was changed to one having the following composition.
<Coating liquid for back layer formation>
54 parts by mass of styrene resin (styrene-acrylonitrile copolymer) 1.5 parts by mass of linear saturated polyester 29.5 parts by mass of zinc stearyl phosphate 15 parts by mass of melamine resin powder 400 parts by mass of methyl ethyl ketone (MEK)

<< Evaluation of print wrinkle prevention >>
Using the thermal transfer sheets obtained in the above Examples and Comparative Examples and a label printer (thermal head: 200 dpi) manufactured by SATO Co., Ltd., a Ladder bar shown in FIG. 4 was placed on a white PET label (72825 manufactured by Avery). A code image and a Picket barcode image shown in FIG. 5 were formed. The printing energy was 6 and the printing speed was 6 IPS (inch per second).
Next, the printing energy was changed to 7, 8, and 9, and a barcode image was formed as described above.
The formed image was visually checked and evaluated based on the following evaluation criteria. Finally, a comprehensive evaluation was conducted based on these results.
In addition, the thermal transfer sheet obtained in Comparative Example 4 could not be evaluated because the transfer layer retention was too low. The same applies to the following evaluation.
(Evaluation criteria)
A: No wrinkling was observed in the prints produced with any of the printing energies.
NG: Wrinkling was observed in at least one of the prints produced with the printing energy.

<< Evaluation of transferability >>
The image formed on the printed matter obtained in the evaluation of the wrinkle prevention property was visually confirmed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: No omission or blurring was observed.
B: Omission and blurring were slightly observed, but no problem was observed in actual use.
NG: Many omissions and blurring were observed, the formed image density was not sufficient, there was a problem in practice, or the transfer layer could not be transferred.

<< Blocking resistance test >>
Two thermal transfer sheets obtained in each of the above Examples and Comparative Examples were prepared, and the heat transfer sheets were superimposed on each other so that the adhesive layer and the back layer faced each other, a load of 0.196 MPa was applied, and the environment was at 40 ° C. and a relative humidity of 85%. For 48 hours. After standing, the two thermal transfer sheets were peeled off and evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1.
(Evaluation criteria)
A: No abnormal transfer of the transfer layer to the back layer was observed.
B: Abnormal transfer of the transfer layer to the back layer was slightly observed.
C: About half of the abnormal transfer of the transfer layer to the back layer was observed.
NG: The entire transfer layer was abnormally transferred to the back layer.

<< Alcohol resistance evaluation >>
Using the thermal transfer sheets obtained in the above Examples and Comparative Examples, and the above label printer, a Picket barcode image shown in FIG. 5 was formed on a white PET label (72825, manufactured by Avery). The printing speed was 6 IPS and the printing energy was 8. The formed image was judged by a bar code checker, and the results are summarized in Table 1.
Under an environment of 22.5 ° C. and a relative humidity of 40%, based on a friction fastness tester II (FR-2S type, manufactured by Suga Test Instruments Co., Ltd., JIS L 0849 (issued in 2013)) The surface of the image formed as described above was rubbed 20 times with a cotton cloth impregnated with 0.5 mL of isopropanol under a load of 200 g. The image after rubbing was judged by a bar code checker, and the results are summarized in Table 1.
In Comparative Examples 2 and 3, the evaluation could not be performed because the formed image density was too low.
(Evaluation results)
A: There was no change in the judgment result by the barcode checker.
B: The judgment result by the barcode checker was reduced by one step.
C: The judgment result by the barcode checker dropped by two or more steps.

10: thermal transfer sheet, 11: back layer, 12: base material, 13: release layer, 14: transfer layer, 15: release layer, 16: coloring layer, 17: adhesive layer

Claims (6)

A back layer containing (meth) acrylic resin, a base material, a release layer containing polyester, and a transfer layer,
The transfer layer includes at least a release layer adjacent to the release layer,
A thermal transfer sheet, wherein the content of the polyester is 50 parts by mass or more based on 100 parts by mass of the total amount of the resin material contained in the release layer.   The thermal transfer sheet according to claim 1, wherein the content of the polyester in the release layer is from 20% by mass to 100% by mass.   The thermal transfer sheet according to claim 1, wherein the release layer further includes a filler.   The thermal transfer sheet according to any one of claims 1 to 3, wherein the content of the filler in the release layer is from 20% by mass to 80% by mass.   The thermal transfer sheet according to claim 1, wherein a thickness of the release layer is 0.05 μm or more and 0.8 μm or less.   The thermal transfer sheet according to claim 1, wherein a thickness of the back layer is 0.2 μm or more and 0.5 μm or less.