JP2009096089A - Thermal transfer image receiving sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer image receiving sheet with improved uniformity, capable of forming images having no consistency unevenness or low spots of print even in a high speed printing. <P>SOLUTION: The thermal transfer image receiving sheet has a porous layer 1 and a dye receiving layer in this order from a base material sheet side on one face of the paper base material sheet. The porous layer 1 is laminated via an adhesive layer (i) provided on the one face of the base material sheet, the adhesive layer (i) includes an adhesive resin with a hardness of E70 or less, measured by a type E durometer hardness test conforming to "Hardness finding method for vulcanized rubber and thermoplastic rubber" of JIS K 6253 (2006). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a thermal transfer image receiving sheet.

As a method of forming an image using thermal transfer, a thermal transfer sheet in which a thermal diffusion dye (sublimation dye) as a recording material is carried on a base sheet such as a plastic film, and another base such as paper or plastic film A thermal diffusion transfer system (sublimation thermal transfer system) is known in which a full-color image is formed by superimposing a thermal transfer image-receiving sheet provided with the dye-receiving layer on a sheet.

In many cases, a paper base material is used as a base material sheet of a thermal transfer image receiving sheet of this thermal diffusion type transfer system (sublimation type thermal transfer system). This is because a relatively smooth base material sheet can be obtained at a low cost, and the printed material after transfer has the merit of obtaining a texture and rigidity comparable to conventional printed materials and silver salt photographs.

In recent years, the printing speed has been increased in the sublimation thermal transfer system.
Along with the increase in printing speed, particularly when a paper base sheet is used, there are problems that density unevenness and printing blur are caused by the uneven shape of the paper. This is because the thermal head is brought into contact with the thermal transfer sheet superimposed on the thermal transfer image receiving sheet and the time for transferring the dye is shortened per unit area, and the time required for the thermal transfer sheet and thermal transfer image receiving sheet to contact the thermal head is reduced. Because it has become shorter per unit area, the thermal head cannot follow the unevenness on the thermal transfer image-receiving sheet due to the uneven shape of the paper, and the heat transferred during normal printing is transmitted according to the unevenness on the thermal transfer image-receiving sheet. This is thought to be due to the lack of density in areas that are not transmitted normally.
As a means for obtaining an image in which density unevenness does not occur, a method of smoothing the thermal transfer image-receiving sheet by adopting a substrate sheet that is as smooth as possible to the thermal transfer image-receiving sheet, or a thermal transfer image-receiving by increasing the force applied to the thermal head A method of printing while crushing unevenness on a sheet is known.

As a method for smoothing the thermal transfer image receiving sheet, for example, a method using a film sheet such as polyethylene terephthalate or polypropylene as a base sheet of the thermal transfer image receiving sheet is known. However, this method has a disadvantage in the texture of the printed matter.
On the other hand, the method of increasing the force applied to the thermal head has a problem that the printer design is likely to be restricted, for example, the size of the printer tends to increase.

On the other hand, by providing a porous layer between the base sheet of the thermal transfer image-receiving sheet and the dye-receiving layer, and utilizing the cushioning property of the porous layer, density unevenness and print blur due to surface irregularities can be reduced. Methods to prevent are known. When a porous layer is provided on a thermal transfer image-receiving sheet, it is widely performed to provide an adhesive layer between the base sheet and the porous layer in order to ensure interlayer adhesion. As such a thermal transfer image-receiving sheet, for example, a sheet (see Patent Document 1) including an adhesive layer containing hollow particles and having voids has been proposed.
However, such a sheet has a problem that the adhesive force of the adhesive layer having voids is insufficient, and fine irregularities derived from the hollow particles are liable to cause uneven density and scumming, and also has insufficient cushioning properties. Met.
For example, Patent Document 2 discloses a sheet in which a porous film layer is laminated on a base sheet via a polyolefin resin layer. However, in such a sheet, the polyolefin resin layer is formed by extrusion lamination, and the adhesion to the base material sheet may be inferior.
JP 2005-186427 A JP 2007-098926 A

An object of the present invention is to provide a thermal transfer image-receiving sheet with improved texture that can form an image free from density unevenness and print blur even when high-speed printing is performed.

The present invention comprises, on one surface of a paper base sheet, a porous layer and a dye receiving layer in order from the base sheet side, and the porous layer (1) is one of the base sheet. The adhesive layer (i) is laminated via an adhesive layer (i) provided on the surface, and the adhesive layer (i) is JIS K 6253 (2006) “Vulcanized rubber and thermoplastic rubber—How to obtain hardness Is a thermal transfer image receiving sheet comprising an adhesive resin having a hardness measured by a type E durometer hardness test conforming to "E70".

The adhesive resin is preferably a urethane resin.
The adhesive layer (i) preferably has a thickness of 2 to 7 μm.
Furthermore, the porous layer (1) is preferably made of porous polyethylene terephthalate [porous PET].
The present invention is described in detail below.

In the present invention, when an adhesive layer containing a low-hardness resin as a constituent component is provided on the dye-receiving layer side of the thermal transfer image-receiving sheet, even if the printing speed is increased, the sensitivity is high, the printing density is high, density unevenness and printing It was completed by finding that an image without blur can be formed.
That is, the thermal transfer image-receiving sheet of the present invention has an adhesive layer (using a resin having lower hardness in addition to improving heat resistance and cushioning properties by providing a porous layer on the dye-receiving layer side of the base sheet). i) is characterized in that the cushioning property is further improved and the smoothness during printing is improved. Therefore, image formation can be performed without affecting the non-uniform shape of the substrate sheet surface. Therefore, the thermal transfer image-receiving sheet of the present invention does not cause density unevenness or print blur due to the non-uniform shape of the substrate sheet surface even when high-speed printing is performed. The thermal transfer image-receiving sheet of the present invention provided with such an adhesive layer (i) is a cushion of the adhesive layer (i) itself, as compared with a sheet provided with an adhesive layer containing a void as in the prior art. Because of its excellent properties, it is excellent in terms of smoothness during printing.

An example of the thermal transfer image receiving sheet of the present invention is shown in FIG. 1 and FIG.
1 is a schematic cross-sectional configuration diagram of the thermal transfer image receiving sheet of the present invention, and FIG. 2 is a schematic cross-sectional configuration diagram of the thermal transfer image receiving sheet of the present invention having a back layer.
As shown in FIG. 1, the thermal transfer image receiving sheet has a porous layer (1) and a dye receiving layer (b) in order from the side of the base sheet (a) on one surface of the base sheet (a). Are stacked. The porous layer (1) is laminated | stacked on the base material sheet (a) through the adhesive bond layer (i).
Moreover, as shown in FIG. 2, a base material sheet (a) has a porous layer (2) and a back surface layer (c) in order from the base material sheet (a) side on the other surface as needed. Are stacked. The porous layer (2) is laminated on the substrate sheet (a) via the adhesive layer (ii).
Hereinafter, the thermal transfer image receiving sheet of the present invention will be described in detail for each layer.

(Substrate sheet)
The substrate sheet is made of paper.
The substrate sheet is used to give the entire thermal transfer image-receiving sheet a texture and rigidity that is comparable to a silver salt photograph.
The paper is not particularly limited, and examples thereof include fine paper, art paper, coated paper, pulp paper such as cast paper, and synthetic paper.
The paper, 78~400g / ^{m 2} basis weight generally preferably 100 to 200 g / ^{m 2.}

The substrate sheet preferably has a thickness of 40 to 300 μm, and more preferably 60 to 200 μm. If the thickness is less than 40 μm, the strength may be insufficient, and if it exceeds 300 μm, it may cause problems such as poor conveyance when printing.

(Adhesive layer (i))
In the present invention, the adhesive layer (i) is laminated on the surface of the base sheet on the dye-receiving layer side between the base sheet and the porous layer (1).
The adhesive layer (i) contributes to improving the cushioning property of the thermal transfer image receiving sheet as described above, in addition to ensuring adhesion between the base material sheet and the porous layer (1).

The adhesive layer (i) has a hardness measured by a type E durometer hardness test in accordance with JIS K 6253 (2006) “Vulcanized rubber and thermoplastic rubber—How to obtain hardness” of E70 or less. Includes adhesive resin.
When the hardness exceeds E70, density unevenness and print blurring occur when printing at high speed. A preferable upper limit of the hardness is E67. The lower limit of the hardness is preferably E40. When it is less than E40, the adhesive sometimes protrudes during processing or printing of the thermal transfer image receiving sheet.

Specifically, the hardness of the adhesive layer (i) is transferred to an aluminum cup having a diameter of 40 mm and dried at 80 ° C. for 24 hours. About a film (diameter 40 mm, thickness 10 mm or more) obtained by curing by this method, a hardness meter for sponge, rubber, and plastic Hardmatic HH-300 series CODE No. Using 811-330 (durometer type E) (manufactured by Mitsutoyo), measurement is performed 15 seconds after pressing.

The adhesive resin is laminated by a known method such as an extrusion laminating method or a dry laminating method to form the adhesive layer (i). Of these, the dry laminating method is preferable.
The adhesive resin is not particularly limited as long as the hardness of the adhesive layer (i) falls within the above range. For example, urethane resin, polyolefin resin, polyester resin, vinyl chloride resin, amide And thermoplastic resins such as styrene resins and styrene resins.

As said urethane type resin, what is obtained by reaction of a polyol and polyisocyanate is used suitably.
Examples of the polyol include ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, and diethylene glycol. , At least one of aliphatic diols such as dipropylene glycol, polyethylene glycol and polypropylene glycol, and a single or mixture of dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, isophthalic acid and terephthalic acid. Polyester diol obtained, or polyoxyalkylene diol or polyester alkylene diol obtained by ring-opening polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, γ-butyrolactone, ε-caprolactone, etc. Etc.

Examples of the polyisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene disilmethane diisocyanate, isophorone diisocyanate, tolylene diisocyanate trimer, hexamethylene diisocyanate trimer, di- or triisocyanate, and the like. Can be mentioned.
Further, in some cases, the polyisocyanate and ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neo At least one compound such as pentyl glycol, diethylene glycol, dipropylene glycol, ethylenediamine, hexamethylenediamine, piperazine, hydrazine, isophoronediamine, dicyclohexylmethanediamine, N-methyldiethanolamine, monoethanolamine, glycerin, trimethylolpropane, pentaerythritol The polymer obtained by making it react may be sufficient.
The said urethane type resin may be used independently and 2 or more types may be used together.

As said polyolefin resin, what has a polymer or copolymer of monoolefins, such as ethylene, propylene, and butene, as a main component is mentioned, for example. For example, high density polyethylene, medium density polyethylene, linear low density polyethylene, low density polyethylene, crystalline polypropylene, crystalline ethylene-propylene-block copolymer, polybutene, poly-3-methylbutene-1, poly-4-methyl Examples include pentene-1, ethylene-vinyl acetate copolymer.

Examples of the polyester resin include polyethylene terephthalate and polybutylene terephthalate.

Examples of the vinyl chloride resin include polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymers, and mixtures thereof.

Examples of the amide resin include nylon 6, nylon 6-6, nylon 6-10, nylon 11 and nylon 12.

Examples of the styrenic resin include polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene terpolymer.

As said adhesive resin, commercially available resin etc. can also be used.
When the adhesive resin is the urethane resin, for example, a mixture of A-365 (Mitsui Chemical Polyurethane, Polyester Polyol) and A-3 (Mitsui Chemical Polyurethane, Isocyanate), A-620 (Mitsui Chemicals). A mixture of Polyurethane, Polyester polyol) and A-65 (Mitsui Chemicals Polyurethane, isocyanate), TM-318 (Toyo Morton, polyether polyol) and CAT-12BL (Toyo Morton, isocyanate) Etc.

As the adhesive resin, a urethane resin is preferable, and a two-component curable urethane resin is particularly preferable. By selecting such an adhesive resin, it can be easily bonded by a dry laminating method.

As a method of forming the adhesive layer (i), a step of preparing an adhesive layer coating solution in which the above-mentioned adhesive resin is dissolved in a solvent, and a base sheet using the adhesive layer coating solution The method which has the process of forming adhesive bond layer (i) on it is mentioned.

As the solvent, conventionally known solvents can be used, for example, alcohols such as ethanol and propanol; cellosolves such as methyl cellosolve and ethyl cellosolve; aromatics such as toluene, xylene and chlorobenzene; acetone, methyl ethyl ketone and the like Ketones; ester solvents such as ethyl acetate and butyl acetate; ethers such as tetrahydrofuran and dioxane; chlorine solvents such as chloroform and trichloroethylene; nitrogen-containing solvents such as dimethylformamide and N-methylpyrrolidone; dimethyl sulfoxide; methyl ethyl ketone , Toluene, and organic solvents such as a mixture thereof.

The adhesive layer (i) preferably has a thickness of 2 to 7 μm, and more preferably 3 to 6 μm, in terms of improving cushioning properties.
In this specification, the thickness of each layer is measured by cross-sectional observation using an electron microscope.

(Porous layer (1))
The porous layer (1) is laminated on the surface of the adhesive layer (i) on the dye-receiving layer side, and gives heat insulation and cushioning properties to the thermal transfer image-receiving sheet to improve printing sensitivity.

In the present invention, the porous layer (1) is not particularly limited, but is preferably a porous heat-resistant resin.
Examples of such a resin include porous polypropylene [porous PP] and porous polyethylene terephthalate [porous PET]. Among these, porous PET is preferable.

The porous layer (1) preferably has a thickness of 15 to 50 μm. If it is less than 15 μm, there is a possibility that sufficient heat insulating properties and cushioning properties may not be obtained, and if it exceeds 50 μm, it may not be preferable in terms of cost.

(Dye-receiving layer)
The dye-receiving layer is mainly composed of a resin.
The resin constituting the dye-receiving layer is preferably one that can be easily dyed with a dye. Examples of such resins include polyolefin resins such as polypropylene; halogenated resins such as polyvinyl chloride resins, polyvinylidene chloride, copolymers of vinyl chloride and vinyl acetate; vinyls such as polyvinyl acetate and polyacrylates. Resins; and copolymers thereof; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polystyrene resins; polyamide resins; copolymers of olefins such as ethylene and propylene and other vinyl monomers; ionomers and cellulose derivatives Can be used alone or as a mixture. Of these, polyester resins and vinyl resins are preferable.

The dye-receiving layer preferably contains a release agent in order to prevent thermal fusion with the thermal transfer sheet during image formation.
Examples of the mold release agent include silicone oil, phosphoric ester plasticizer fluorine compound, vinyl chloride-vinyl acetate copolymer, and among them, silicone oil is preferable.
The dye receiving layer may contain one type of release agent or two or more types.

As the silicone oil, modified silicone oils such as epoxy-modified, alkyl-modified, amino-modified, fluorine-modified, phenyl-modified, and epoxy / polyether-modified are preferable. Of these, vinyl-modified silicone oil and hydrogen-modified silicone oil are preferable.

In general, the content (total amount) of the release agent may be 0.2 to 30 parts by mass per 100 parts by mass of the solid content of the resin constituting the dye-receiving layer.

The dye-receptive layer may contain known additives such as an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a pigment, an antistatic agent, a plasticizer, and a heat-meltable substance as long as the effects of the present invention are not impaired. It may be appropriately blended.

As a method for forming the dye-receiving layer, the above-mentioned resin, a mold release agent as required, and an additive are added to a solvent and kneaded to produce a dye-receiving layer coating solution, and the dye-receiving layer The method of apply | coating a coating liquid on the surface on the opposite side of the base material sheet of the above-mentioned porous layer (1), and drying is mentioned.

The dye-receiving layer coating solution generally has a solid content concentration of 5% by mass or more. The upper limit of the solid content concentration is generally 50% by mass or less because if the concentration becomes too high, the storage stability may decrease and the viscosity may increase.

A conventionally well-known thing can be used as said solvent, For example, what was mentioned regarding adhesive bond layer (i) is mentioned.

The dye-receiving layer coating solution can be applied by a conventionally known method such as a gravure printing method, a screen printing method, or a reverse roll coating method using a gravure plate.
The dye-receiving layer coating solution is generally, 0.5 to 50 g / ^{m 2} approximately in the dry state, preferably 2 to 10 g / ^{m 2.}

Drying of the dye-receiving layer coating solution can generally be performed at a temperature of 50 to 150 ° C.

(Primer layer)
In the thermal transfer image-receiving sheet of the present invention, a primer layer can be provided between the dye-receiving layer and the porous layer (1) as necessary.

Examples of the primer layer include a layer obtained by curing a thermoplastic resin, a thermosetting resin, or a thermoplastic resin having a functional group with various curing agents.
Examples of the resin constituting the primer layer include polyvinyl alcohol, polyvinyl pyrrolidone, polyester, chlorinated polypropylene, modified polyolefin, urethane resin, acrylic resin, polycarbonate, ionomer, monofunctional and / or polyfunctional hydroxyl group-containing prepolymer. .
As said hardening | curing agent, what was illustrated regarding adhesive bond layer (i) can be used similarly.

The primer layer includes a step of producing a primer layer coating solution in which the above-described resin and additives to be added as necessary are dissolved in a solvent, and the primer layer coating solution is combined with the above-described dye-receiving layer coating solution. It can form by the method including the process of apply | coating by the same method and drying.
The coating thickness is preferably 0.5 to 30 g / m ^{2 in} a dry state.

As the additive, titanium oxide, zinc oxide, magnesium carbonate, calcium carbonate and the like are preferably used in order to impart whiteness and concealment.
In order to enhance whiteness, stilbene compounds, benzimidazole compounds, benzoxazole compounds, etc. are added as fluorescent whitening agents, and hindered amine compounds, hindered phenols are used to increase the light fastness of printed materials. -Based compounds, benzotriazole-based compounds, benzophenone-based compounds, etc. are added as UV absorbers or antioxidants, or cationic acrylic resins, polyaniline resins, various conductive fillers, etc. are added to impart antistatic properties. May be.

(Resin layer and adhesive layer (ii))
In the thermal transfer image receiving sheet of the present invention, for the purpose of curling prevention, a resin having a balance between the porous layer (1) and the thermal contraction rate and moisture permeability is provided on the surface opposite to the dye receiving layer of the substrate sheet. It is preferable that the layers are laminated. Various plastic films or sheets can be used for the resin layer, and the resin layer is not particularly limited. Although it can be set as a conventionally well-known composition, such as a heat resistant resin containing a porous film and a hollow particle, it is preferable to set it as the same composition as the above-mentioned porous layer (1).
The resin layer preferably has a thickness of 15 to 50 μm.

The resin layer can be laminated via the adhesive layer (ii).
Although it does not specifically limit as said adhesive bond layer (ii), It is preferable to set it as the composition similar to the above-mentioned adhesive bond layer (i). By setting the adhesive layer (ii) to such a composition, it is possible to obtain a sheet with more excellent cushioning properties.

The resin layer and the adhesive layer (ii) can be laminated in the same manner as the porous layer (1) and the adhesive layer (i) described above.

(Back layer)
When the above-described resin layer is formed on the thermal transfer image-receiving sheet of the present invention, on the surface of the resin layer opposite to the base sheet, for the purpose of improving the transportability of the thermal transfer image-receiving sheet and preventing curling, A back layer can be provided.

The back layer generally comprises a resin such as an acrylic resin, a cellulose resin, a polycarbonate resin, a polyvinyl acetal resin, a polyvinyl alcohol resin, a polyamide resin, a polystyrene resin, a polyester resin, or a halogenated polymer. is there.

The back layer is more preferably one obtained by curing the above resin with a curing agent.
As the curing agent, generally known ones can be used, and among them, an isocyanate compound is preferable. The resin of the back layer reacts with an isocyanate compound or the like to form a urethane bond and crosslink, thereby improving heat resistant storage stability and solvent resistance, and also improving interlayer adhesion.

An organic filler or an inorganic filler may be added to the back surface layer as an additive. The function of these fillers improves the transportability of the thermal transfer image receiving sheet in the printer, and can also improve the storage stability of the thermal transfer image receiving sheet, such as preventing blocking.

Examples of the organic filler include acrylic filler, polyamide filler, fluorine filler, and polyethylene wax. Of these, polyamide filler is particularly preferred.
Examples of the inorganic filler include silicon dioxide and metal oxides.

The method for forming the back layer is not particularly limited. For example, the step of preparing a coating liquid composed of the above-described constituents and the coating liquid on the surface of the porous layer (2) are applied. The method including the process to do is mentioned.
When the back layer is provided, a primer layer provided between the dye-receiving layer and the porous layer (1) is previously provided for the purpose of ensuring adhesion with the porous layer (2). You may provide on the surface on the opposite side.

(Antistatic layer)
In the thermal transfer image-receiving sheet of the present invention, an antistatic layer may be provided on the outermost surface of the dye-receiving layer surface, the back surface, or both surfaces.

The antistatic layer is prepared by dissolving or dispersing an antistatic agent such as a fatty acid ester, a sulfate ester, a phosphate ester, an amide, a quaternary ammonium salt, a betaine, an amino acid, an acrylic resin, or an ethylene oxide adduct in a solvent. Can be formed by coating The coating amount of the antistatic layer is preferably 0.001 to 0.1 g / m ² when dried.

(Other)
The heat transfer image-receiving sheet of the present invention can form an image by superimposing a heat transfer sheet containing a heat transfer dye and a binder and transferring the heat transfer dye.

As the thermal transfer sheet, the above-described dye layer is provided on a base material sheet, and a conventionally known one can be used.
The thermal transfer sheet may be provided with a heat-resistant slip layer as necessary.

The heat transfer dye in the dye layer is not particularly limited as long as it is a conventionally known dye. For example, diarylmethane dyes; triarylmethane dyes; thiazole dyes; merocyanine dyes; methine dyes such as pyrazolone methine Indoaniline dyes; azomethine dyes such as acetophenone azomethine, pyrazoloazomethine, imidazolazomethine, imidazoazomethine, pyridone azomethine; xanthene dyes; oxazine dyes; cyanomethylene dyes such as dicyanostyrene and tricyanostyrene; thiazines Azine dyes; acridine dyes; benzeneazo dyes; pyridoneazo, thiophenazo, isothiazoleazo, pyrroleazo, pyralazo, imidazoleazo, thiadiazoleazo, triazoleazo, dizazo, etc. System dye; spiropyran dyes; Indian Linus Piropi run based dyes; fluoran dyes; rhodamine lactam-based dyes; naphthoquinone dyes; anthraquinone dyes; quinophthalone dyes.

It does not specifically limit as a binder in the said dye layer, A conventionally well-known resin binder can be used.
Examples of the resin binder include cellulose resins such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, and cellulose butyrate; polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, Vinyl resins such as polyacrylamide; polyester resins; phenoxy resins;

The dye layer may be only one or two dye layers of yellow, magenta, and cyan, or may include all layers of each color, and if necessary, a black layer. A layer may be added.

It does not specifically limit as a base material sheet in the said heat transfer sheet, For example, resin films, such as a polyester film, are mentioned.

The image formation is not particularly limited as long as it is performed at a temperature within the above range, and can be performed by a known thermal diffusion transfer system (sublimation thermal transfer system).

Since the image formation is performed using the above-described thermal transfer image-receiving sheet of the present invention as an object to be transferred, an image having a highest maximum density can be formed, and a printed matter free from defects such as density unevenness can be obtained.

Since the thermal transfer image-receiving sheet of the present invention has the above-described configuration, in addition to being able to obtain a printed matter having excellent heat resistance and a high maximum reached density, an image free from defects such as density unevenness even when printed at high speed Can be formed.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples and Comparative Examples.
In the text, “part” or “%” is based on mass unless otherwise specified.

Example 1
As a porous layer (1), an adhesive layer coating solution of 5.0 g / m ² (solid content) having the following composition was formed on one side of a polyethylene terephthalate film (Toyobo Co., Ltd., FK003, thickness 38 μm) having microvoids. The adhesive layer (i) was formed by coating with a gravure printing machine and drying.
Furthermore, using the high-quality paper (basis weight 157 g / m ² ) as the base sheet, the formed adhesive layer (i) was bonded to one surface of the base sheet.
Further, on the other surface of the fine paper, a polyethylene terephthalate film (manufactured by Toray Industries, Inc., T-60, thickness 25 μm) and an adhesive layer (ii) using the above-described adhesive coating solution are provided. Through 0 g / m ² (solid content) (the adhesive layer (ii) was formed by coating and drying with a gravure printing machine), bonding and bonding substrates were produced.
On the porous layer (1) of the bonded substrate, the intermediate layer coating solution having the following composition was coated with a wire bar so as to be ² g / m ² after drying, and dried at 110 ° C. for 1 minute. The receiving layer coating solution having the following composition was dried and coated with a wire bar so as to be 4 g / m ² and dried at 110 ° C. for 1 minute.

(Adhesive layer coating solution composition)
Polyester polyol (A-365: Mitsui Chemicals Polyurethanes) 20 parts isocyanate (A-3: Mitsui Chemicals Polyurethanes) 1 part Ethyl acetate 11.6 parts

(Coating liquid composition for intermediate layer)
Polyester resin (WR-905, manufactured by Nippon Synthetic Chemical) 13.1 parts Titanium oxide (TCA-888, manufactured by Tochem Products) 26.2 parts Optical brightener (benzimidazole derivative, product name; Ubitex BAC, Ciba Japan Co., Ltd.) 0.39 parts water / isopropyl alcohol [IPA] (mass ratio 2/1) 60 parts

(Dye-receiving layer coating solution composition)
Vinyl chloride / vinyl acetate copolymer (Solvine C, manufactured by Nissin Chemical Co., Ltd.) 60 parts Epoxy-modified silicone (X-22-3000T, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.2 parts Modified silicone (X-24-510, Shin-Etsu) 0.6 parts methyl ethyl ketone / toluene (mass ratio 1/1) 5 parts

Example 2
A thermal transfer image receiving sheet was prepared in the same manner as in Example 1 except that the composition of the adhesive layer coating solution was changed as follows.

(Adhesive layer coating solution composition)
Polyether polyol (TM-318: manufactured by Toyo Morton) 100 parts isocyanate (CAT-12BL: manufactured by Toyo Morton) 100 parts ethyl acetate 490 parts

Example 3
A thermal transfer image receiving sheet was prepared in the same manner as in Example 1 except that the composition of the adhesive layer coating solution was changed as follows.

(Adhesive layer coating solution composition)
Polyester polyol (A-620: Mitsui Chemicals Polyurethane) 16 parts isocyanate (A-65: Mitsui Chemicals Polyurethanes) 1 part Ethyl acetate 42.6 parts

Comparative Examples 1-8
A thermal transfer image-receiving sheet was produced in the same manner as in Example 1 except that the composition of the adhesive layer coating solution was changed as shown in Table 1. The composition of the resin and the curing agent used in the adhesive layer coating solution is shown in Table 1.

(Evaluation)
The thermal transfer image-receiving sheets obtained in Examples and Comparative Examples were evaluated by the following methods. The results are shown in Table 1.

Hardness of the adhesive layer (i) Using the adhesive layer coating solution used in each example and comparative example, JIS K 6253 (2006) "Vulcanized rubber and thermoplastic rubber-Determination of hardness" It was determined by a compliant type E durometer hardness test.
That is, first, the adhesive layer coating solution was transferred to an aluminum cup having a diameter of 40 mm and dried at 80 ° C. for 24 hours.
Next, for a film (diameter 40 mm, thickness 10 mm or more) obtained by curing by this method, a hardness meter for sponges, rubbers and plastics, hardmatic HH-300 series CODE No. The hardness was measured by using 811-330 (durometer type E) (manufactured by Mitsutoyo) 15 seconds after pressing.

Sensitivity (blur print)
The thermal transfer image-receiving sheet of each example and comparative example was cut, and the thermal transfer sheet for video printer CP-600 manufactured by Canon Co., Ltd. was used as the thermal transfer film, and the dye receiving layer surface and the dye layer of the thermal transfer sheet were opposed to each other. , Yellow (Y), magenta (M), and cyan (C) in this order, thermal transfer recording was performed with a thermal head using a video printer CP-600 manufactured by Canon Inc. from the back surface of the thermal transfer sheet.
The printing pattern is a 9-step gradation test pattern for each color, and the degree of blurring of the printing was measured visually. The evaluation criteria are as follows.
○: Density unevenness and print blur are not recognized. Δ: Density unevenness and print blur are present, but the level is established as a printed material. ×: Density unevenness and print blur is not conspicuous as a printed material.

From Table 1, the sample of the example had a low hardness of the adhesive layer, and no blur was observed in the printed material, but the sample of the comparative example had a high hardness of the adhesive layer, and the evaluation of the blur of the printed material was low. It was inferior.

The thermal transfer image-receiving sheet of the present invention is excellent in heat resistance and can form an image free from defects such as density unevenness, and therefore can be suitably used for high-speed printing.

It is a typical section lineblock diagram of the thermal transfer image receiving sheet of the present invention. FIG. 2 is a schematic cross-sectional configuration diagram of the thermal transfer image receiving sheet of the present invention having a back surface layer.

Explanation of symbols

a. Base sheet b. Dye-receiving layer c. Back layer 1. 1. porous layer Porous layer i. Adhesive layer ii. Adhesive layer

Claims (4)

On one surface of the paper base sheet, a porous layer (1) and a dye receiving layer are provided in this order from the base sheet side, and the porous layer (1) is one surface of the base sheet. The adhesive layer (i) is laminated via an adhesive layer (i) provided thereon, and the adhesive layer (i) is JIS K 6253 (2006) “Vulcanized rubber and thermoplastic rubber—How to obtain hardness” A thermal transfer image-receiving sheet comprising an adhesive resin having a hardness measured by a type E durometer hardness test in conformity with E70, which is E70 or less. The thermal transfer image receiving sheet according to claim 1, wherein the adhesive resin is a urethane resin. The thermal transfer image-receiving sheet according to claim 1 or 2, wherein the adhesive layer (i) has a thickness of 2 to 7 µm. The thermal transfer image-receiving sheet according to claim 1, 2 or 3, wherein the porous layer (1) comprises porous polyethylene terephthalate (porous PET).

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