JP5568851B2 - Thermal transfer image receiving sheet and printing method - Google Patents

Description

The present invention relates to a thermal transfer image receiving sheet and a printing method using the 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 recent years, image formation by a thermal transfer method has been used for the purpose of creating a color image from digital data such as a digital camera, and the demand thereof is increasing year by year.
Further, by making the image formed by the thermal transfer system a postcard size, the printed matter has been used as a picture postcard. In this way, when a printed matter by the thermal transfer method is used as a picture postcard, it is necessary to write an address or the like on the surface (back surface) opposite to the image forming surface, so that backside writing is required.

Examples of a method for imparting writing properties to the back surface of the thermal transfer image-receiving sheet include, for example, Patent Documents 1, 2, and 3 that form a porous layer on the back surface of the thermal transfer image-receiving sheet using a hydrophilic filler, or a hard filler. And a method of imparting fine irregularities with a hard resin is disclosed.
However, these methods generally have no problem with writing with writing instruments, but when printing using an ink jet printer, there are problems such as blurring of printing, and the ink on the back side is slow to dry. There has been a problem that contamination is caused by shifting to other printed materials.

Further, for example, Patent Document 4 discloses a dye thermal transfer receiving sheet in which a back surface coating layer containing nylon particles is formed on a sheet-like support, and Patent Document 5 discloses a back surface of a base sheet. A thermal transfer image-receiving sheet is disclosed in which a back layer comprising a hydrophilic porous layer and a back coating layer containing a nylon filler is formed. According to the image-receiving sheet disclosed in these documents, in addition to the writing property by the writing tool on the back surface, the writing property by the ink jet printer can be provided.
However, even with the image-receiving sheets described in these documents, it is difficult to say that the ink absorption and quick-drying properties are sufficient when printed by an ink jet printer of the back coating layer. It was not possible to sufficiently prevent the problem of contamination caused by shifting to other printed materials.
Japanese Patent Laid-Open No. 6-239036 JP-A-9-175048 Japanese Patent Laid-Open No. 9-175052 JP 2000-335120 A JP 2002-337463 A

In view of the above situation, the object of the present invention is excellent in absorbency and quick-drying of ink printed by the ink jet system of the back layer, and suitably preventing contamination due to transfer of the ink to other printed matter. Another object of the present invention is to provide a thermal transfer image-receiving sheet that is excellent in writing properties with writing instruments such as water-based, aqueous gel, and oil-based ink, and a printing method using the thermal transfer image-receiving sheet.

The present invention is a thermal transfer image-receiving sheet provided with a back layer on one surface side of a base sheet, wherein the back layer contains resin fine particles having an average particle diameter of 20 to 40 times the thickness of the back layer. The thermal transfer image receiving sheet is characterized in that the resin fine particles are contained in an amount of 50 to 500 parts by mass with respect to 100 parts by mass of the binder resin, and the average particle size of the resin fine particles is 28 to 40 μm .

Also, the fine resin particles, nylon particles, (meth) acrylate-based fine particles, urethane particles, polyester particles, polycarbonate particles, polyethylene particles, polypropylene particles, silicone particles, polystyrene fine particles and phenolic particulate It is preferably at least one selected from the group consisting of
In addition, the thermal transfer image receiving sheet of the present invention preferably has a primer layer between the base sheet and the back surface layer.

The present invention is also a printing method characterized by printing on the back layer of the thermal transfer image receiving sheet of the present invention by an ink jet printing method.
The present invention is described in detail below.

As a result of intensive studies, the inventors of the present invention have used the above-mentioned resin fine particles in a thermal transfer image-receiving sheet having a dye-receiving layer on one side of a base sheet and a back layer containing resin fine particles on the other side. By having an average particle diameter that is extremely large compared to the resin fine particles contained in the back layer of the thermal transfer image-receiving sheet and within a predetermined range with respect to the thickness of the back layer, It has been found that when ink-jet printing is performed, the printed ink has excellent absorbency and quick-drying properties, and the printed ink can be suitably prevented from being transferred to and contaminated with other thermal transfer image-receiving sheets. It came to be completed.

The thermal transfer image receiving sheet of the present invention includes a back surface layer on one surface side of the base material sheet.
The substrate sheet is generally composed of paper or a plastic film.
The papers may be single paper or processed paper, for example, high-quality paper, coated paper, art paper, cast coated paper, paperboard, impregnated paper such as resin emulsion or synthetic rubber latex, Synthetic resin-added paper is exemplified. The papers may be laminated papers of various plastic films, or may be synthetic papers such as polystyrene synthetic paper and polyolefin synthetic paper.

Examples of the plastic film include a polyolefin resin film, a hard polyvinyl chloride film, a polyester resin film, a polystyrene film, a polycarbonate film, a polyacrylonitrile film, and a polymethacrylate film.
The plastic film may be a transparent film, a white opaque film formed by adding a white pigment or a filler, or a foamed film.
The plastic film may be used alone or as a laminate in combination with papers or different plastic films as described above.

When forming the dye-receiving layer and the back layer, the substrate sheet can be provided with a corona discharge treatment, a primer layer, and an intermediate layer on the substrate sheet as necessary.

The thickness of the base sheet is generally 10 to 400 μm, preferably 100 to 300 μm. If the thickness is less than 10 μm, stiffness may be insufficient, and if it exceeds 400 μm, it may cause a paper jam.

The back layer contains resin fine particles.
The resin fine particles give the thermal transfer image-receiving sheet of the present invention transportability in a printer such as a thermal transfer apparatus or an inkjet printing apparatus, and also give the back layer the absorbency and quick drying of ink printed by the inkjet printing method. It plays the role of preventing the ink printed on other thermal transfer image-receiving sheets and the like from migrating, and further, the role of making the writing property of writing instruments such as water-based, water-based gel and oil-based ink excellent. .

In the thermal transfer image receiving sheet of the present invention, the resin fine particles have an average particle diameter of 20 to 40 times the thickness of the back layer. If it is less than 20 times, the ink printed on the back surface layer by the ink jet printing method is inferior in the absorbency and quick-drying property, and it is not possible to sufficiently prevent the ink printed on other thermal transfer image-receiving sheets from migrating, Writability with writing instruments will also be inferior. Moreover, it becomes easy to arrange | position to a back surface layer in the state in which several resin fine particles were laminated | stacked, and it becomes difficult to make it a single layer form mentioned later. When it exceeds 40 times, the resin fine particles are detached from the back surface layer, and the appearance of the thermal transfer image receiving sheet is deteriorated. In the present specification, the average particle diameter of the resin fine particles is a value measured by a laser diffraction particle size distribution measuring method.

The resin fine particles may be either spherical or non-spherical, but are preferably spherical considering the transportability of the thermal transfer image-receiving sheet of the present invention in the printer. When the resin fine particles are non-spherical, the average particle diameter of the resin fine particles means an average particle diameter when the non-spherical resin fine particles are spherical with the same volume.

The thickness of the back layer means the thickness of the portion of the back layer excluding the resin fine particles, and specifically, the shortest distance from the surface of the back layer on the base sheet side to the opposite side of the surface Means the average distance.
Although it does not specifically limit as thickness of the said back surface layer, It is preferable that it is about 0.4-4.0 micrometers. If it is less than 0.4 μm, the resin fine particles are liable to fall off, and the absorbency, quick drying property of ink printed by the ink jet method of the back layer, and writing property with a writing instrument may be insufficient. If it exceeds 4.0 μm, the average particle diameter of the resin fine particles described above becomes extremely large, and the appearance of the thermal transfer image-receiving sheet of the present invention may deteriorate. A more preferable lower limit is 0.7 μm, and a more preferable upper limit is 3.0 μm.
In the thermal transfer image receiving sheet of the present invention, the thickness of the back layer is particularly preferably 1 μm. At this time, the average particle diameter of the resin fine particles is 20 to 40 μm.

The resin fine particles are preferably arranged in a single layer on the back layer.
The term “arranged in the form of a single layer” means that the resin fine particles are arranged in the back surface layer without overlapping in the thickness direction of the back surface layer. Since the resin fine particles are arranged in a single layer, the resin fine particles are less likely to drop off, and the thermal transfer image-receiving sheet of the present invention has excellent transportability in the printer.
In addition, as a method of arranging the resin fine particles in a single layer, for example, there is a method of adjusting the blending amount of the resin fine particles in the back layer to a range as described later, and applying to one side of the base sheet. Preferably mentioned.

The resin fine particles are not particularly limited, but nylon fine particles, (meth) acrylate fine particles, urethane fine particles, polyester fine particles, polycarbonate fine particles, polyethylene fine particles, polypropylene fine particles, silicone fine particles, polystyrene fine particles, and phenol. It is preferably at least one selected from the group consisting of system fine particles. Among these, nylon fine particles and / or (meth) acrylate fine particles are preferable. When the back surface layer contains these resin fine particles, the thermal transfer image-receiving sheet of the present invention is not only quick-drying, but also smooth transportability as image-receiving paper, difficulty in scratching other printing sheets, printing It also excels in the ability to scatter things.
The (meth) acrylate means acrylate or methacrylate.

The raw material of the nylon fine particles is not particularly limited, and examples thereof include nylon 6, nylon 66, nylon 12, nylon 46, nylon 11, nylon 610, nylon 6T, nylon 6I, nylon 9T, and nylon M5T. Among these, nylon 12 is preferable because it is excellent in water resistance and has no characteristic change due to water absorption.

It does not specifically limit as a raw material of the said (meth) acrylate type microparticles | fine-particles, For example, polyethyl (meth) acrylate, polybutyl (meth) acrylate, etc. are mentioned. Among them, polymethyl methacrylate (PMMA) is preferable because it is excellent in transparency, inexpensive, and easily available, and cross-linked PMMA is particularly preferably used.

The back layer preferably contains 50 to 500 parts by mass of the resin fine particles with respect to 100 parts by mass of a binder resin described later. If the amount is less than 50 parts by mass, the absorbency, quick-drying property of ink printed on the back surface layer by the ink jet printing method, and writing property with a writing tool may be insufficient. If it exceeds 500 parts by mass, the resin fine particles are likely to fall off from the back layer, and the resin fine particles may not be arranged in a single layer structure on the back layer. A more preferred lower limit is 100 parts by mass, and a more preferred upper limit is 300 parts by mass.

The back layer contains a binder resin.
The binder resin is not particularly limited, and examples thereof include resins such as acrylic resins, cellulose resins, polycarbonate resins, polyvinyl acetal resins, polyvinyl alcohol resins, polyamide resins, polystyrene resins, polyester resins, and halogenated polymers. Can be mentioned.
Among these binder resins, among them, polyvinyl alcohol resins, water-soluble acrylic resins, water-soluble polyester resins, and water-soluble urethane resins are preferable because they easily exhibit functions such as water absorption.

Furthermore, for example, a cationic acrylic resin, a polyaniline resin, various conductive fillers, and the like may be added to the back layer in order to impart antistatic properties.

The method for forming the back layer is not particularly limited. For example, the resin fine particles, binder resin, curing agent, and other additives added as necessary are dissolved in a suitable organic solvent. Or a dispersion dispersed in a mixed solvent of an organic solvent such as isopropyl alcohol and water (hereinafter, these are also referred to as coating solutions for the back layer), for example, gravure printing method, screen printing method And a method of applying and drying on one surface side of the substrate sheet by a forming means such as a reverse coating method using a gravure plate and a method using a bar coater.

There are no particular limitations on the additive added to the back surface layer coating liquid as necessary, and examples include conventionally known antifoaming agents, dispersants, colored dyes, fluorescent dyes, fluorescent pigments, and ultraviolet absorbers. Can be mentioned.

In addition, the thermal transfer image receiving sheet of the present invention preferably has a primer layer between the base sheet and the back surface layer.
The primer layer is a layer that plays a role of improving adhesion between the base sheet and the back surface layer, preventing curling of the thermal transfer image receiving sheet of the present invention, and the like.
The binder resin used in the primer layer is not particularly limited, and a conventionally known adhesive resin can be used. For example, polyurethane resin, polyester resin, polycarbonate resin, polyamide resin, polyvinyl acetate resin, Examples include vinyl chloride-vinyl acetate copolymer resin, polyvinyl acetal resin, polyvinyl butyral resin, polyvinyl alcohol resin, epoxy resin, cellulose resin, ethylene-vinyl acetate copolymer resin, polyethylene resin, polypropylene resin, and the like. Further, among these resins, those having an active hydroxyl group can further be used as a cured resin of those isocyanates.

The primer layer is preferably added with a filler such as titanium oxide, zinc oxide, magnesium carbonate, or calcium carbonate in order to impart whiteness and concealment.
The primer layer may contain, for example, a stilbene compound, a benzimidazole compound, or a benzoxazole compound as a fluorescent whitening agent in order to improve whiteness.
In addition, the primer layer is added with, for example, a hindered amine compound, a hindered phenol compound, a benzotriazole compound, a benzophenone compound, or the like as an ultraviolet absorber or an antioxidant in order to increase the light resistance of the printed matter. May be.
Furthermore, the primer layer may be added with, for example, a cationic acrylic resin, a polyaniline resin, various conductive fillers, etc. in order to impart antistatic properties.

The coating amount of the primer layer is preferably about 0.5 to 30 g / m ^{2 in} a dry state, for example.

The thermal transfer image receiving sheet of the present invention has a dye receiving layer on the side surface opposite to the back surface layer of the substrate sheet.
The dye receiving layer contains a binder resin as a main component.
The binder resin in the dye-receiving layer is not particularly limited as long as it is a known resin used in a conventionally known thermal transfer image-receiving sheet. For example, the following synthetic resins can be used.

(A) Resin polyester resin having an ester bond, polyacrylate resin, polycarbonate resin, polyvinyl acetate resin, styrene acrylate resin, vinyl toluene acrylate resin, and the like.
(B) Resin polyurethane resin having a urethane bond.
(C) Resin polyamide resin having an amide bond.
(D) Resin urea resin having a urea bond.
(E) Other highly polar bonds Polycaprolactone resin, styrene-maleic anhydride resin, polyvinyl chloride resin, polyacrylonitrile resin, vinyl chloride / vinyl acetate copolymer, ethylene / vinyl acetate copolymer, polychlorinated Halogenated polymers such as vinylidene, polyvinyl acetate, etc.
The synthetic resin may be a copolymer or may be used in combination of two or more.

The dye-receiving layer preferably contains a release agent in addition to the binder resin described above, from the viewpoint of ensuring releasability from the thermal transfer sheet to be superimposed during transfer.

The release agent is not particularly limited, and examples thereof include known ones such as silicone oil, phosphate ester compounds, and fluorine compounds, and silicone oil is particularly preferable.

Examples of the silicone oil include epoxy-modified silicone oil, alkyl-modified silicone oil, amino-modified silicone oil, fluorine-modified silicone oil, phenyl-modified silicone oil, epoxy / polyether-modified silicone oil, vinyl-modified silicone oil, hydrogen-modified silicone oil, etc. The modified silicone oil is preferred.
The release agent is preferably added so as to be in the range of 0.5 to 30 parts by mass with respect to 100 parts by mass of the binder resin. When the amount is less than 0.5 parts by mass, the releasing effect is insufficient. When the amount exceeds 30 parts by mass, the dye acceptability is lowered and the printing density may be insufficient.

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 the method for forming the dye-receiving layer, a step of producing a dye-receiving layer coating liquid by adding the above-mentioned binder resin, and if necessary, a release agent or an additive to a solvent and kneading, and the dye The method of apply | coating the coating liquid for receiving layers on the above-mentioned base material sheet, 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.

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 dye receiving layer coating solution can be applied by a conventionally known method such as a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, or a method using a bar coater.
The dye-receiving layer coating solution is generally, 0.5~50.0g / ^{m 2} approximately in the dry state, preferably 2.0~10.0g / ^{m 2.}

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

The thermal transfer image receiving sheet of the present invention may have a porous film between the dye receiving layer and the substrate sheet.
The porous film preferably has a high surface glossiness, for example, because of its flexibility, it has excellent adhesion to the thermal head and good productivity. The used porous film having fine voids inside is preferable.

Examples of the method for generating fine voids in the film include the following methods.
That is, first, a compound is prepared by kneading one or more organic fine particles or inorganic fine particles that are incompatible with the resin serving as the base of the film.
When this compound is viewed microscopically, the base resin and fine particles incompatible with the base resin form a fine sea-island structure.
Next, this compound is formed into a film and stretched.
Thereby, fine voids can be generated by peeling of the sea-island interface or large deformation of the region forming the island.

Moreover, as a method of forming the fine voids, for example, a method of forming by adding polyester or acrylic resin mainly composed of polypropylene and having a melting point higher than that of polypropylene may be mentioned. In this case, polyester or acrylic resin serves as a nucleating agent that forms fine voids.
It is preferable that content of the said polyester and an acrylic resin is 2-10 mass parts with respect to 100 mass parts of polypropylene in any case. When the amount is less than 2 parts by mass, generation of fine voids is insufficient, and sufficient print sensitivity may not be obtained. When the amount exceeds 10 parts by mass, the heat resistance of the porous film may be reduced. .

Moreover, when producing the porous film which uses polypropylene as the base resin, it is preferable to further add polyisoprene in order to generate finer and dense voids. Thereby, higher print sensitivity can be obtained. For example, a porous film having high printing sensitivity can be obtained by preparing a compound mainly composed of polypropylene, blended with acrylic resin or polyester, and polyisoprene, forming a compound, and stretching.

The minimum with the preferable thickness of the said porous film is 30 micrometers, and a preferable upper limit is 60 micrometers. If it is less than 30 μm, the porous film may be crushed when the image is printed, and the image quality may be impaired. When the thickness exceeds 60 μm, the image becomes good, but the thermal transfer image-receiving sheet of the present invention becomes unnecessarily thick, which is not preferable in terms of cost.

Moreover, it is preferable that the said porous film is bonded together through the said base material sheet and an adhesive bond layer.
It does not specifically limit as said adhesive bond layer, For example, it can select suitably according to bonding methods, such as the method of making it adhere | attach by the electron beam irradiation after dry lamination, wet lamination, and sticking.
The adhesive used in the adhesive layer is not particularly limited. For example, vinyl acetate resin, acrylic resin, vinyl acetate-acrylic copolymer resin, vinyl acetate-vinyl chloride copolymer resin, ethylene-vinyl acetate copolymer Examples thereof include those containing a coalesced resin, a polyamide resin, a polyvinyl acetal resin, a polyester resin, a polyurethane resin and the like as components.

Furthermore, between the porous film and the dye receiving layer, imparting performance such as adhesion between the dye receiving layer and the porous film, whiteness, cushioning property, concealing property, antistatic property and anti-curl property. For this purpose, a conventionally known intermediate layer may be provided.
As binder resin used for the said intermediate | middle layer, the thing similar to the binder resin in the primer layer mentioned above is mentioned, for example.

The thermal transfer image-receiving sheet of the present invention can form an image by superimposing a thermal transfer sheet containing a heat-transferable dye and a binder on the dye-receiving layer and causing the heat-transferable dye to transfer heat.

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).

The thermal transfer image-receiving sheet of the present invention having the above-described configuration has resin fine particles whose particle diameter is extremely large on the back surface layer and whose average particle diameter is within a predetermined range with respect to the thickness of the back surface layer. When printing is performed on the back layer by the ink jet method, the applied ink is quickly absorbed into the gaps between the resin fine particles. That is, the ink printed on the back surface layer by the ink jet method does not come into direct contact with other thermal transfer image receiving sheets.
Therefore, the thermal transfer image-receiving sheet of the present invention can prevent contamination due to ink migration even when another thermal transfer image-receiving sheet or the like is stacked on the back surface layer after ink-jet printing.
Similarly, when writing on the back layer with a writing instrument such as water-based, water-based gel, or oil-based ink, these inks and the like are quickly absorbed into the gaps between the resin fine particles and are in direct contact with other thermal transfer image-receiving sheets. No contamination due to migration of the ink or the like can be prevented.
That is, the thermal transfer image receiving sheet of the present invention has excellent quick drying properties.
Furthermore, since the thermal transfer image receiving sheet of the present invention has resin fine particles having the above-mentioned particle diameter on the back surface layer, even if an undried binder resin is included in the back surface layer, There is no direct contact with the binder resin, and contamination with the undried binder resin can also be prevented.

Such a thermal transfer image-receiving sheet of the present invention is produced, for example, by forming the back layer on one side of the base sheet by the method described above and forming the dye-receiving layer on the other side by the method described above. can do.

In addition, a printing method characterized by printing on the back layer of the thermal transfer image receiving sheet of the present invention by an ink jet method is also one aspect of the present invention.

In the ink jet printing, the ink used is not particularly limited, and a conventionally known ink for ink jet printing can be used. Specifically, for example, an aqueous dye type, an aqueous pigment type, an oily dye type, and an oily pigment type can be used.

In the printing method of the present invention, the printing method using the inkjet method is not particularly limited, and examples thereof include a method using a conventionally known inkjet printer.

Since the thermal transfer image-receiving sheet of the present invention has the above-described configuration, when ink-jet printing is performed on the back surface layer, the ink is excellent in ink absorbability and quick-drying, so that the ink migrates to other printed materials. Contamination caused by this can be suitably prevented, and the writing property with a writing instrument such as aqueous, aqueous gel, or oil-based ink can also be excellent.

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.

( Reference Example 1 )
A polyethylene terephthalate film having a thickness of 125 μm is used as a base sheet, and a coating solution for a dye receiving layer having the following composition is applied on one surface of the base sheet by a wire bar coating method with a coating amount of 5.0 g / m ² (solid content ) And dried at a temperature of 110 ° C. for 2 minutes.

(Dye-receiving layer coating solution)
Vinyl chloride / vinyl acetate copolymer resin [VA ST-PSC, manufactured by Nissin Chemical Co., Ltd.]
100 parts epoxy-modified silicone oil [X-22-3000T manufactured by Shin-Etsu Chemical Co., Ltd.] 1 part main chain both-end alcohol-modified silicone oil [X-22-160AS manufactured by Shin-Etsu Chemical Co., Ltd.] 0.1 part main chain One-end alcohol-modified silicone oil [X-22-176DX, manufactured by Shin-Etsu Chemical Co., Ltd.] 0.1 part XDI violet (Takenate A-14, manufactured by Mitsui Takeda Chemical Co., Ltd.) 0.5 part solvent (methyl ethyl ketone / toluene) Ratio 1: 1) 17 parts

Next, a primer layer coating solution having the following composition was applied to the side surface of the base sheet opposite to the surface on which the dye-receiving layer was formed at a coating amount of 1 g / m ² (solid content) by a wire bar coating method. It was dried for 1 minute to form a primer layer having a thickness of 1 μm.

(Primer layer coating solution)
Polyurethane resin (Nippon Polyurethane Industry Co., Ltd., Nippon Run 5199) 5 parts isocyanate curing agent (Mitsui Chemicals Polyurethanes, Takenate A-14) 10 parts methyl ethyl ketone / toluene / isopropyl alcohol (mass ratio 2: 2: 1) 70 copies

And the coating liquid for back surface layers of the following composition is apply | coated on the formed primer layer, it is made to dry on 100 degreeC and the conditions for 1 minute, a 1 micrometer-thick back layer is formed, The thermal transfer image receiving which concerns on the reference example 1 A sheet was produced. In addition, the solvent used the mixed solvent which mixed water and isopropyl alcohol (IPA) by mass ratio 1: 1.

(Coating liquid for back layer)
IJC403A (manufactured by Yushi Kogyo Co., Ltd., PVA resin, solid content 16%) 7.5 parts by mass of resin fine particles (Orgasol 1002 D NAT1, average particle size 20 μm, 6 nylon, manufactured by Arkema) 1.2 parts by mass Solvent 15.3 parts by mass

(Examples 3-5 , 7 , 8 , Comparative Examples 1-14, Reference Examples 2, 3 )
Except for changing the resin fine particles to those shown in Table 1 in the backside layer coating liquid, in the same manner as in Reference Example 1, Example 3～5,7,8, Comparative Examples 1 to 14 and Reference Example 2 3 thermal transfer image receiving sheets were prepared.

(Evaluation)
The thermal transfer image-receiving sheets obtained in Examples 3 to 5, 7, and 8, Comparative Examples 1 to 14, and Reference Examples 2 and 3 were cut into A6 sizes to produce evaluation samples. The IJ evaluation pattern shown in FIG. 1 was printed on the back layer of each sample for evaluation using Canon PIXUS iP8600. In addition, the IJ evaluation pattern shown in FIG. 1 is printed in three steps in each color of yellow, purple, black, and light blue from the top.
The printer settings were as follows.
Printer Setting Paper Type: Postcard Print Quality: Clean Paper Size: Postcard

After printing, after a predetermined time has elapsed, the plain paper is stacked with a load of 1 kg and 30 seconds (2 × 12 cm) applied to the back surface layer, and the presence or absence of ink transfer to the plain paper is confirmed. Evaluation was made according to the criteria of the stage. The following results are shown in Table 1. In addition, those having an evaluation of 3 or more have absorptivity and quick-drying property at a level that causes no problem in practical use.
(Evaluation criteria)
Ink transfer was not observed after 5:30 seconds. Ink transfer was not observed after 4: 1 minutes. Ink transfer was not observed after 3: 2 minutes. No transfer of ink was observed 1: 4 minutes after transfer was not observed

As shown in Table 1, the thermal transfer image-receiving sheet according to the example contains resin fine particles having an average particle diameter of 20 to 40 μm (20 to 40 times the thickness of the back layer) on the back layer. It was excellent in the absorptivity and quick-drying property of the ink printed by the inkjet system to the back layer.
On the other hand, in the thermal transfer image-receiving sheet according to the comparative example, the average particle diameter of the resin fine particles in the back layer is less than 20 times the thickness of the back layer, and is inferior in the absorptivity and quick drying of ink printed by the ink jet method. It was a thing.

The thermal transfer image-receiving sheet of the present invention is excellent in the absorbability and quick-drying property of ink printed by the ink jet system of the back layer, and can suitably prevent contamination due to the transfer of the ink to other printed materials.

It is a figure which shows an IJ evaluation pattern.

Claims (4)

A thermal transfer image receiving sheet comprising a back layer on one side of the base sheet, and a dye receiving layer on the other side of the base sheet,
The back layer contains resin fine particles having an average particle diameter of 20 to 40 times the thickness of the back layer, and contains 50 to 500 parts by mass of resin fine particles with respect to 100 parts by mass of the binder resin .
The thermal transfer image receiving sheet, wherein the resin fine particles have an average particle diameter of 28 to 40 m . The resin fine particles are selected from the group consisting of nylon fine particles, (meth) acrylate fine particles, urethane fine particles, polyester fine particles, polycarbonate fine particles, polyethylene fine particles, polypropylene fine particles, silicone fine particles, polystyrene fine particles and phenolic fine particles. The thermal transfer image-receiving sheet according to claim 1, which is at least one selected. The thermal transfer image receiving sheet according to claim 1 or 2, further comprising a primer layer between the base sheet and the back surface layer. A printing method comprising printing on the back layer of the thermal transfer image-receiving sheet according to claim 1, 2 or 3 by an inkjet printing method.