JP7145409B2 - thermal transfer sheet - Google Patents

Description

The present invention relates to thermal transfer sheets.

Conventionally, energy is applied using a thermal head or the like to a thermal transfer sheet comprising a substrate such as a resin film and a transfer layer having a colored layer containing a coloring material, and a transfer target such as paper or a plastic sheet is applied. 2. Description of the Related Art A hot melt transfer method is known in which a printed matter is produced by transferring a transfer layer onto a body and forming an image.
Since images formed by the thermal fusion transfer method have high density and excellent sharpness, the method is suitable for recording binary images such as characters and line drawings. Further, according to the thermal fusion transfer method, variable information such as address, customer information, numbering, bar code, etc. can be recorded on the transferred material using a computer and a thermal transfer printer.

For example, a phenolic resin is added to the colored layer of the thermal transfer sheet for the purpose of improving the scratch resistance of the printed matter.
However, printed matter produced from such a thermal transfer sheet may be erased by alcohol such as isopropanol (IPA), and there is room for improvement in alcohol resistance.

Further, the transfer layer provided in such a thermal transfer sheet is usually required to have high transferability and adhesion to a transfer receiving material.

The present invention has been made in view of the above problems, and the problem to be solved is to be able to produce a printed matter having high alcohol resistance and abrasion resistance, as well as high transferability and transferability to a transferred material. To provide a thermal transfer sheet provided with a transfer layer having adhesion of

The thermal transfer sheet of the present invention comprises a base material, a colored layer, and a transfer layer comprising an adhesive layer in this order, the colored layer containing a polyester and a coloring material, and the adhesive layer containing a phenolic resin and a polyester. , the content of polyester in the adhesive layer is 15% by mass or more and 90% by mass or less.

In one embodiment, the softening point of the phenolic resin is 90° C. or higher.

In one embodiment, the content of the phenolic resin in the adhesive layer is 10% by mass or more and 85% by mass or less.

In one embodiment, the polyester contained in the adhesive layer has a number average molecular weight of 2000 or more and 20000 or less.

In one embodiment, the polyester contained in the adhesive layer has a glass transition temperature of 35° C. or higher and 85° C. or lower.

In one embodiment, the sum of the content of phenolic resin and polyester in the adhesive layer is 90% by mass or more.

In one embodiment, the polyester content in the colored layer is 20% by mass or more and 90% by mass or less.

In one embodiment, the transfer layer comprises a release layer below the colored layer.

ADVANTAGE OF THE INVENTION According to this invention, the thermal transfer sheet which can produce the printed matter which has high alcohol resistance and abrasion resistance, and is provided with the transfer layer which has high transferability and adhesiveness to a transfer-receiving body.

1 is a schematic cross-sectional view showing one embodiment of a thermal transfer sheet of the present invention; FIG. 1 is a schematic cross-sectional view showing one embodiment of a thermal transfer sheet of the present invention; FIG. It is a figure which shows the picket barcode image formed in the Example.

(Thermal transfer sheet)
As shown in FIG. 1, the thermal transfer sheet 10 of the present invention comprises a substrate 11 and a transfer layer 14 comprising a colored layer 12 and an adhesive layer 13 in this order.
In one embodiment, the transfer layer 14 further comprises a release layer 15 below the colored layer 12, as shown in FIG.
In one embodiment, as shown in FIGS. 1 and 2, the thermal transfer sheet 10 of the present invention further comprises a backing layer 16 on the surface of the substrate 11 opposite to the surface on which the transfer layer 14 is provided.
Furthermore, in one embodiment, the thermal transfer sheet 10 of the present invention may further include a release layer and a primer layer on the substrate (not shown).

Each layer included in the thermal transfer sheet according to the present invention will be described below.

(Base material)
The base material has heat resistance to withstand the thermal energy applied during thermal transfer (for example, heat from a thermal head), and has mechanical strength and solvent resistance to support the colored layer, etc. provided on the base material. If so, you can use it without any restrictions.

Examples of base materials include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene dimethylene terephthalate, terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, and the like. polyester, polyamides such as nylon 6 and nylon 6,6, polyolefins 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 polyvinylpyrrolidone (PVP), (meth)acrylic resins such as polyacrylate, polymethacrylate and polymethyl methacrylate, imide resins such as polyimide and polyetherimide, cellophane, cellulose acetate , cellulose resins such as nitrocellulose, cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB), styrene resins such as polystyrene (PS), polycarbonates, and films composed of ionomer resins (hereinafter simply “ "Resin film") can be used.
Among the above resins, polyesters such as PET and PEN are preferable, and PET is particularly preferable, from the viewpoint of heat resistance and mechanical strength.
In the present invention, "(meth)acryl" means to include both "acryl" and "methacryl". Moreover, "(meth)acrylate" means to include both "acrylate" and "methacrylate".

Moreover, the laminated body of the above-mentioned resin film can also be used as a base material. A laminate of resin films can be produced 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. It is preferred to use

The thickness of the substrate is preferably 2.0 μm or more and 25.0 μm or less, more preferably 3.0 μm or more and 10.0 μm or less. Thereby, the mechanical strength of the substrate and the transmission of thermal energy during thermal transfer can be improved.

(transfer layer)
The transfer layer included in the thermal transfer sheet of the present invention includes at least a colored layer and an adhesive layer. Also, in one embodiment, the transfer layer further comprises a release layer below the colored layer.

(Colored layer)
The thermal transfer sheet of the present invention comprises a colored layer containing polyester and a colorant. Moreover, in the present invention, polyester means a copolymer of a dicarboxylic acid compound and a diol compound.
Dicarboxylic acid compounds 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, cyclohexanedicarboxylic acid, decalinedicarboxylic 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-sodiumsulfoisophthalic acid, phenylendanedicarboxylic acid, anthracenedicarboxylic acid, phenanthenedicarboxylic acid, 9,9'-bis (4-Carboxyphenyl)fluoric acid and their ester derivatives.
Examples of diol compounds include ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol, and cyclohexane. diethanol, decahydronaphthalenedimethanol, decahydronaphthalenediethanol, norbornanedimethanol, norbornanediethanol, tricyclodecanedimethanol, tricyclodecaneethanol, tetracyclododecanedimethanol, tetracyclododecanediethanol, decalindimethanol, decalindiethanol, 5 -methylol-5-ethyl-2-(1,1-dimethyl-2-hydroxyethyl)-1,3-dioxane, cyclohexanediol, bicyclohexyl-4,4'-diol, 2,2-bis(4-hydroxy cyclohexylpropane), 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 and pentaerythritol.

The polyester may contain a monomer other than the dicarboxylic acid compound and the diol compound as long as the properties of the present invention are not impaired, but the content thereof is preferably 40 mol% or less with respect to all structural units. , is more preferably 30 mol % or less, more preferably 20 mol % or less.

Moreover, the colored layer can contain two or more kinds of polyesters.

The polyester content in the colored layer is preferably 20% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 80% by mass or less. This makes it possible to further improve the alcohol resistance and abrasion resistance of printed matter (hereinafter simply referred to as printed matter) produced using the thermal transfer sheet of the present invention.

The coloring material contained in the colored layer is not particularly limited, and is preferably selected as appropriate according to the required color tone and the like, and inorganic pigments, organic pigments, dyes, and the like can be used. For example, when it is desired to form a bar code image, it is preferable to use a material that has sufficient black density and does not discolor or fade due to light, heat, or the like. Examples of such coloring materials include carbon black such as lamp black, graphite, and nigrosine dyes.

Moreover, the colored layer can contain two or more kinds of coloring materials.

The content of the coloring material in the colored layer is preferably 10% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 70% by mass or less. Thereby, the density of the formed image can be improved.

The colored layer can contain a resin material other than polyester as long as the characteristics of the present invention are not impaired. Examples of resin materials include polyamides, polyolefins, vinyl resins, (meth)acrylic resins, imide resins, cellulose resins, and styrene resins.

The colored layer may contain additives such as fillers, plasticizers, antistatic agents, ultraviolet absorbers, inorganic fine particles, organic fine particles, releasing agents and dispersing agents, as long as the properties of the present invention are not impaired.

The thickness of the colored layer is preferably 0.2 μm or more and 2 μm or less, more preferably 0.3 μm or more and 1.5 μm or less. As a result, the transferability of the transfer layer can be further improved, and the density of the formed image can be improved.

The colored layer is formed by dispersing or dissolving the above material in water or an appropriate solvent, and coating the material by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating and rod coating. , to form a coating film on a substrate or the like, and then drying the film.

(adhesive layer)
The thermal transfer sheet of the present invention comprises an adhesive layer containing phenolic resin and polyester. The adhesive layer is a layer provided on the outermost surface of the transfer layer, and can improve the adhesion of the transfer layer to the object to be transferred.
In the present invention, the phenolic resin means a resin containing 50 mol % or more of structural units having a phenolic hydroxyl group with respect to all structural units.
For example, phenolic resins include phenol, cresol, ethylphenol, aminophenol, nitrophenol, naphthol, alkyl-substituted naphthol, catechol, resorcinol, hydroquinone, dihydroxynaphthalene, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, terpene diphenol. , 4,4′-biphenol, 2,2′-biphenol, 3,3′,5,5′-tetramethyl-[1,1′-biphenyl]-4,4′-diol, naphthalenediol, tris-( phenolic compounds such as 4-hydroxyphenyl)methane and 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane; aldehyde compounds such as formaldehyde, acetaldehyde, benzaldehyde, hydroxybenzaldehyde and hydroxyacetophenone; dicyclopentadiene; furfural; , 4,4′-bis(chloromethyl)-1,1′-biphenyl, 4,4′-bis(methoxymethyl)-1,1′-biphenyl, 1,4′-bis(chloromethyl)benzene and 1 , 4′-bis(methoxymethyl)benzene and other compounds.
Among the above phenolic resins, a novolak phenolic resin, which is a copolymer of a phenolic compound and an aldehyde compound, is preferred for the reason of improving the adhesion of the transfer layer to the object to be transferred.

The softening point of phenolic resin is 90° C. or higher. As a result, the abrasion resistance of the printed matter can be significantly improved.
From the viewpoint of scratch resistance of printed matter, the softening point of the phenolic resin is more preferably 95° C. or higher, more preferably 100° C. or higher. Also, the softening point of the phenol resin is preferably 125° C. or less.
In addition, in this invention, the softening point of resin is measured based on JISK7234.

Also, the adhesive layer can contain two or more phenolic resins.

The content of the phenol resin in the adhesive layer is preferably 10% by mass or more and 85% by mass or less, more preferably 15% by mass or more and 80% by mass or less. As a result, the transferability of the transfer layer and the adhesion to the transferred material can be further improved.

As the polyester contained in the adhesive layer, the same polyester as that contained in the colored layer can be used. Moreover, from the viewpoint of adhesion between the adhesive layer and the colored layer, it is preferable that the polyester contained in the adhesive layer and the polyester contained in the colored layer are the same.
In addition, the adhesive layer can contain two or more kinds of polyester.

The number average molecular weight (Mn) of the polyester is preferably 2000 or more and 20000 or less, more preferably 2500 or more and 18000 or less. As a result, the alcohol resistance of the printed matter can be further improved, and the transferability of the transfer layer can be further improved.
In the present invention, Mn is a value obtained in terms of polystyrene by gel permeation chromatography (GPC) according to JIS K 7252-1 (2008).

The glass transition temperature (Tg) of the polyester is preferably 35°C or higher and 85°C or lower, more preferably 38°C or higher and 83°C or lower. As a result, the alcohol resistance of the printed matter can be further improved, and the transferability of the transfer layer and the adhesion to the transfer-receiving body can be further improved.
In the present invention, Tg is a value determined by differential scanning calorimetry (DSC) in accordance with JIS K 7121.

Also, the adhesive layer can contain two or more polyesters.

The content of polyester in the adhesive layer is 15% by mass or more and 90% by mass or less. As a result, the alcohol resistance of the printed matter can be significantly improved, and the adhesion of the transfer layer to the transferred material can be significantly improved.
From the viewpoint of the alcohol resistance of the printed material and the adhesion of the transfer layer to the transfer material, the polyester content is preferably 20% by mass or more and 87% by mass or less, and more preferably 23% by mass or more and 80% by mass. % or less.

The colored layer can contain the above-mentioned resin materials other than the phenolic resin and the polyester and the above-mentioned additives as long as the properties of the present invention are not impaired.

The thickness of the adhesive layer is preferably 0.1 μm or more and 0.6 μm or less, more preferably 0.2 μm or more and 0.5 μm or less. As a result, the transferability of the transfer layer and the adhesion to the transferred material can be further improved.

The adhesive layer is formed by dispersing or dissolving the above material in water or an appropriate solvent, and coating the adhesive layer by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating and rod coating. , to form a coating film on a colored layer or the like, and then drying the film.

(Release layer)
In one embodiment, the transfer layer included in the thermal transfer sheet of the present invention includes a release layer below the colored layer. Thereby, the transferability of the transfer layer can be further improved.

In one embodiment, the release layer contains wax as a major component. Examples of waxes include natural waxes such as beeswax, spermaceti, Japan wax, rice bran wax, carnauba wax, candelilla wax and montan wax, paraffin wax, microcrystalline wax, oxidized wax, ozokerite, ceresin, ester wax and polyethylene wax. synthetic waxes, higher saturated fatty acids such as margaric acid, lauric acid, myristic acid, palmitic acid, stearic acid, furoic acid and behenic acid, higher saturated monohydric alcohols such as stearyl alcohol and behenyl alcohol, higher esters such as fatty acid esters of sorbitan , higher fatty acid amides such as stearic acid amide and oleic acid amide. Among these, carnauba wax is preferable from the viewpoint of transferability of the transfer layer.
In addition, the release layer can contain two or more kinds of waxes.

The wax content in the release layer is preferably 70% by mass or more and 99% by mass or less, more preferably 80% by mass or more and 98% by mass or less. Thereby, the transferability of the transfer layer can be further improved.

Also, in one embodiment, the release layer contains a resin material as a main component. By including a resin material as a main component in the release layer, the abrasion resistance of the printed matter can be further improved. Examples of resin materials include (meth)acrylic resins, cellulose resins, vinyl resins, polyurethanes, silicone resins, and fluorine resins.

The content of the resin material in the release layer is preferably 70% by mass or more and 99% by mass or less, more preferably 80% by mass or more and 98% by mass or less. This makes it possible to further improve the abrasion resistance of the printed matter while maintaining the transferability of the transfer layer.

The thickness of the release layer is preferably 0.1 μm or more and 3.0 μm or less, more preferably 0.2 μm or more and 2.0 μm or less. Thereby, the transferability of the transfer layer can be further improved.

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

(back layer)
In one embodiment, the thermal transfer sheet of the present invention comprises a backing layer on the side of the substrate not provided with the transfer layer. As a result, sticking and wrinkles due to heating during thermal transfer can be prevented.

In one embodiment, the back layer comprises a resin material, such as cellulose resin, styrene resin, vinyl resin, polyester, polyurethane, silicone-modified polyurethane, fluorine-modified polyurethane, and (meth)acrylic resin.

In one embodiment, the back layer comprises inorganic or organic particles. This makes it possible to further prevent sticking and wrinkles due to heating during thermal transfer.
Examples of 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 oxides such as silica. , graphite, saltpeter, and inorganic particles such as boron nitride. The organic particles include organic resin particles made of (meth)acrylic resin, Teflon (registered trademark) resin, silicone resin, lauroyl resin, phenol resin, acetal resin, styrene resin, polyamide, etc., or reacting these with a cross-linking agent. Examples include crosslinked resin particles obtained by

The thickness of the back layer is preferably 0.1 μm or more and 2 μm or less, more preferably 0.1 μm or more and 1 μm or less. This makes it possible to prevent the occurrence of sticking, wrinkles, etc., while maintaining the transferability of thermal energy during thermal transfer.

The back layer is formed by dispersing or dissolving the above material in water or an appropriate solvent, and coating the material by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating and rod coating. , to form a coating film by applying it on a substrate, and drying it.

(release layer)
In one embodiment, the thermal transfer sheet of the present invention comprises a release layer between the substrate and the transfer layer. Thereby, the transferability of the thermal transfer layer can be improved.

In one embodiment, the release layer comprises a resin material, such as (meth)acrylic resins, polyurethanes, acetal resins, polyamides, polyesters, melamine resins, polyol resins, cellulose resins and silicone resins.

In one embodiment, the release layer contains a release material such as silicone oil, phosphate ester plasticizer, fluorine compound, wax, metallic soap, and filler.

The thickness of the release layer is not particularly limited, and can be, for example, 0.2 μm or more and 2 μm or less.

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

(primer layer)
In one embodiment, the thermal transfer sheet of the present invention comprises a primer layer on one or both sides of the substrate. This can improve the adhesion between the substrate and the adjacent layer.

In one embodiment, the primer layer comprises resinous materials such as polyesters, vinyl resins, polyurethanes, (meth)acrylic resins, polyamides, polyethers, styrene resins and cellulose resins.

The thickness of the primer layer is not particularly limited, and can be, for example, 0.2 μm or more and 2 μm or less.

The primer layer is formed by dispersing or dissolving the above materials in water or an appropriate solvent, and applying the coating by known means such as roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating and rod coating. , to form a coating film by applying it on a substrate, and drying it.

EXAMPLES 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
A PET film having a thickness of 4.5 μm was prepared, and a release layer forming coating liquid having the following composition was applied to one surface of the PET film and dried to form a release layer having a thickness of 0.5 μm.
<Coating solution for forming release layer>
・ Carnauba wax 100 parts by mass (WE-95, manufactured by Chukyo Yushi Co., Ltd.)
・Water 50 parts by mass ・Isopropanol (IPA) 150 parts by mass

A colored layer-forming coating liquid having the following composition was applied onto the release layer formed as described above and dried to form a colored layer having a thickness of 0.5 μm.
<Coating liquid for forming colored layer>
- Carbon black 33.4 parts by mass (Mitsubishi Chemical Co., Ltd., C / B # 25)
・ Polyester 33.3 parts by mass (Byron (registered trademark) 200, manufactured by Toyobo Co., Ltd.)
・ Polyester 33.3 parts by mass (Byron (registered trademark) 220, manufactured by Toyobo Co., Ltd.)
・Toluene 200 parts by mass ・Methyl ethyl ketone (MEK) 200 parts by mass

A coating solution for forming an adhesive layer having the following composition was applied onto the colored layer formed as described above and dried to form an adhesive layer having a thickness of 0.3 μm.
<Coating solution for forming adhesive layer>
· Phenolic resin 5.3 parts by mass (DIC Corporation, Phenolite (registered trademark) TD-2090, novolac type, softening point 120 ° C.)
・ Polyester 2 parts by mass (Unitika Ltd., Elitel (registered trademark) UE-3380, Mn8000, Tg60 ° C.)
・MEK 62.7 parts by mass

On the other side 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 0.1 μm to obtain a thermal transfer sheet.
<Coating solution for forming back layer>
・Acrylic-modified silicone resin 10 parts by mass (manufactured by Natoco Co., Ltd., polyalloy NSA-X55)
・MEK 20 parts by mass

Examples 2-10 and Comparative Examples 1-12
A thermal transfer sheet was produced in the same manner as in Example 1, except that the composition of the colored layer and the composition of the adhesive layer were changed to those shown in Tables 1 and 2.
The details of each component in Tables 1 and 2 are as follows.
<Colored layer>
((meth)acrylic resin)
・ Dianal (registered trademark) BR-87: manufactured by Mitsubishi Chemical Corporation <adhesive layer>
(Phenolic resin)
・ Phenolite (registered trademark) TD2093Y: manufactured by DIC Corporation, novolak type, softening point 100°C
- Shaunol (registered trademark) BRG556: manufactured by Aica Kogyo Co., Ltd., novolac type, softening point 80 ° C.
(polyester)
・ Vylon (registered trademark) 220: manufactured by Toyobo Co., Ltd., Mn 3000, Tg 53 ° C.
・ Vylon (registered trademark) 885: manufactured by Toyobo Co., Ltd., Mn 8000, Tg 79 ° C.
・ Elitel (registered trademark) UE-3320: manufactured by Unitika Ltd., Mn 1800, Tg 40 ° C.
・ Vylon (registered trademark) 290: manufactured by Toyobo Co., Ltd., Mn 22000, Tg 72 ° C.
(vinyl chloride-vinyl acetate copolymer)
・ Solbin (registered trademark) CNL: manufactured by Nissin Chemical Industry Co., Ltd., Mn 12000, Tg 76 ° C.
((meth)acrylic resin)
・ Dianal (registered trademark) BR-87: manufactured by Mitsubishi Chemical Corporation (ethylene-vinyl acetate copolymer)
・ Evaflex (registered trademark) EV 205WR: manufactured by Mitsui DuPont Polychemicals Co., Ltd.

Comparative example 13
A thermal transfer sheet was produced in the same manner as in Example 1, except that the composition and thickness of the colored layer were changed as shown in Table 2 and the adhesive layer was not provided.

<<Evaluation of Transferability>>
Using the thermal transfer sheets obtained in the above Examples and Comparative Examples and a printer (SD3C, manufactured by Markem Image), a print density of 140% and a print speed of 140% are printed on the PET surface of the PET-LLDPE laminated film that is the object to be transferred. A picket bar code image shown in FIG. 3 was formed under conditions of 10 m/min and a pressure of 0.35 MPa. The formed image was visually confirmed and evaluated based on the following evaluation criteria. The evaluation results are summarized in Tables 1 and 2.
(Evaluation criteria)
A: It was confirmed that a good image was formed with no crushing or fading in the image.
B: Collapse and/or faintness was observed in part of the image, but there was no practical problem.
NG: Could not transfer and could not form an image.

<<Alcohol resistance evaluation>>
In an environment of 22.5 ° C. and 40% humidity, the surface of the image formed as described above was measured using a Gakushin type friction fastness tester (manufactured by Tester Sangyo Co., Ltd., AB-301). A cotton cloth impregnated with 5 mL was rubbed 10 times with a load of 200 g, and the image after rubbing was visually observed and evaluated based on the following evaluation criteria. The evaluation results are summarized in Tables 1 and 2. Note that Comparative Example 13 could not be evaluated because transfer was not possible.
(Evaluation criteria)
A: No new image defects were observed after rubbing.
B: New image defects were observed after rubbing, but they were small and practically non-problematic.
NG: A new image defect was observed after rubbing, and there was a problem in practical use.

<<Scratch resistance evaluation>>
The surface of the image formed as described above was rubbed back and forth with a thumb 20 times in an environment of 22.5° C. and 40% humidity. The image after rubbing was visually observed and evaluated based on the following evaluation criteria. The evaluation results are summarized in Tables 1 and 2. Comparative Example 10 could not be evaluated because transfer was not possible.
(Evaluation criteria)
A: No new image defects were observed after rubbing.
B: New image defects were observed after rubbing, but they were small and practically non-problematic.
NG: A new image defect was observed after rubbing, and there was a problem in practical use.

<<Adhesion Evaluation>>
A tape (48 mm×18 mm, manufactured by Otsuka Shokai Co., Ltd., TANOSEE OPP tape thin) was strongly attached to the surface of the image formed as described above, and left to stand for 1 minute. After standing still, the tape was peeled off at a peel angle of 180 degrees in an environment of 22.5° C. and 40% humidity. The image after peeling was evaluated based on the following evaluation criteria. The evaluation results are summarized in Tables 1 and 2. Note that Comparative Example 13 could not be evaluated because transfer was not possible.
(Evaluation criteria)
A: No new image defects were observed after peeling.
B: A new image defect was observed after peeling, but it was small and practically non-problematic.
NG: A new image defect was observed after peeling, and there was a problem in practical use.

10: Thermal transfer sheet, 11: Base material, 12: Colored layer, 13: Adhesive layer, 14: Transfer layer, 15: Release layer, 16: Back layer

Claims (8)

A transfer layer comprising a substrate, a colored layer, and an adhesive layer in this order,
The colored layer contains a polyester and a coloring material,
The adhesive layer contains a phenolic resin and polyester,
The sum of the contents of the phenolic resin and the polyester in the adhesive layer is 90% by mass or more,
A thermal transfer sheet, wherein the content of polyester in the adhesive layer is 15% by mass or more and 90% by mass or less. 2. The thermal transfer sheet according to claim 1, wherein the phenolic resin has a softening point of 90[deg.] C. or higher. The thermal transfer sheet according to claim 1 or 2, wherein the content of the phenol resin in the adhesive layer is 10% by mass or more and 85% by mass or less. The thermal transfer sheet according to any one of claims 1 to 3, wherein the polyester contained in the adhesive layer has a number average molecular weight of 2000 or more and 20000 or less. The thermal transfer sheet according to any one of claims 1 to 4, wherein the polyester contained in the adhesive layer has a glass transition temperature of 35°C or higher and 85°C or lower. The thermal transfer sheet according to any one of claims 1 to 5, wherein the polyester contained in the adhesive layer has a number average molecular weight of 2000 or more and 8000 or less. The thermal transfer sheet according to any one of claims 1 to 6, wherein the polyester content in the colored layer is 20% by mass or more and 90% by mass or less. The thermal transfer sheet according to any one of Claims 1 to 7, wherein the transfer layer comprises a release layer below the colored layer.

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