JP5641406B2 - Thermal transfer image-receiving sheet and method for producing the same - Google Patents

Description

  The present invention relates to a thermal transfer image-receiving sheet having a substrate and a receiving layer on the substrate, and a method for producing the same.

  Conventionally, various printing methods are known. Among them, the thermal diffusion type transfer method (sublimation type thermal transfer method) uses a sublimation dye as a color material, so that density gradation can be freely adjusted, and intermediate colors and gradations can be adjusted. It has excellent tone reproducibility and can form high-quality images comparable to silver halide photographs.

  This thermal diffusion transfer system is a method in which a thermal transfer ink sheet containing a dye (sublimation dye) and a thermal transfer image receiving sheet are superposed, and then the ink sheet is heated by a thermal head whose heat generation is controlled by an electrical signal. The dye in the ink sheet is transferred to the image receiving sheet to record image information. As such thermal diffusion transfer systems become widespread, the printing speed has been increased, and sufficient color density can be obtained even if the conventional thermal energy is printed using the conventional thermal transfer ink sheet and thermal transfer image receiving sheet. There are problems such as inability to obtain.

  Furthermore, there are various other problems in the thermal diffusion transfer system. For example, due to insufficient releasability of the image receiving sheet, the ink sheet sticks to the receiving layer surface of the image receiving sheet at the time of printing, and when the ink sheet is peeled off from the image receiving layer after printing, generation of peeling sound, Problems such as poor running and occurrence of peeling lines on the image have occurred.

  In order to solve the various problems as described above, a method has been proposed in which a water-soluble polymer is crosslinked by adding a crosslinking agent to the heat insulating layer of the thermal transfer image-receiving sheet (for example, see Patent Document 1). There has also been proposed a method of hardening a gelatin by adding a specific hardener to the receiving layer of the thermal transfer recording sheet (see, for example, Patent Document 2). However, none of the methods has been evaluated for uneven printing (hereinafter, also referred to as “burn”) in a high-temperature and high-humidity environment of the thermal transfer image-receiving sheet.

  Therefore, thermal transfer can improve various performances such as burnt performance, water resistance, image density, etc. while maintaining various performances such as adhesion of each layer and moisture and heat resistance of the printed products. Development of an image receiving sheet is eagerly desired.

JP 2008-246777 A JP 2008-6781 A

  The present invention has been made in view of the above-mentioned background art, and its purpose is to maintain the various properties such as the adhesion of each layer and the moisture resistance and heat resistance of the printed material, while the burned performance and water resistance of the printed material. Another object of the present invention is to provide a thermal transfer image-receiving sheet that can improve various performances such as image density and a method for producing the same.

  As a result of intensive studies to solve the above problems, the present inventors have added a specific epoxy crosslinking agent to any layer on the substrate in the thermal transfer image-receiving sheet having at least a heat insulating layer and a receptor layer on the substrate. As a result, the inventors have found that the above problems can be solved, and have completed the present invention.

That is, according to one aspect of the present invention,
A thermal transfer image-receiving sheet having a base material and a heat insulating layer and a receiving layer on the base material,
The heat insulating layer includes hollow particles;
The receiving layer includes a binder resin;
The thermal insulation layer and / or the receiving layer comprises a cross-linking agent;
There is provided a thermal transfer image-receiving sheet, wherein the crosslinking agent comprises an epoxy crosslinking agent having an epoxy equivalent of 300 or less and a functional group number of 2 or more.

According to another aspect of the present invention,
A method for producing the above thermal transfer image-receiving sheet,
There is provided a method for producing a thermal transfer image receiving sheet, wherein all layers constituting the receiving layer from the heat insulating layer are formed by an aqueous coating method and a simultaneous multilayer coating method.

  According to the thermal transfer image-receiving sheet of the present invention, while maintaining various performances such as adhesion of each layer and moisture and heat resistance of the printed material, various performances such as burning performance, water resistance and image density of the printed material are improved. It is possible to provide a thermal transfer image-receiving sheet that can be manufactured and a method for producing the same.

Thermal transfer image-receiving sheet The thermal transfer image-receiving sheet of the present invention comprises a base material, and a heat insulating layer and a receiving layer on the base material. In a preferred embodiment, the thermal transfer image receiving sheet may further have an intermediate layer between the heat insulating layer and the receiving layer.

Substrate The substrate in the present invention has a role of holding the receiving layer and heat is applied at the time of thermal transfer. Therefore, the substrate may be a material having a mechanical strength that does not hinder handling even in an overheated state. preferable.

  Examples of such a base material include condenser paper, glassine paper, sulfuric acid paper, high-size paper, synthetic paper (polyolefin-based, polystyrene-based), high-quality paper, art paper, coated paper, and cast-coated paper. , Wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, paperboard, cellulose fiber paper, or polyester, polyacrylate, polycarbonate, polyurethane, polyimide, polyetherimide, cellulose derivatives , Polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, acrylic, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone, polyether mon And films such as chlorofluorocarbon, tetrafluoroethylene, perfluoroalkyl vinyl ether, polyvinyl fluoride, tetrafluoroethylene / ethylene, tetrafluoroethylene / hexafluoropropylene, polychlorotrifluoroethylene, and polyvinylidene fluoride. A white opaque film formed by adding a white pigment or a filler to the synthetic resin can be used, and is not particularly limited. Moreover, the laminated body by the arbitrary combinations of the said base material can also be used. Examples of typical laminates include cellulose fiber paper and synthetic paper, or synthetic paper of cellulose synthetic paper and a plastic film. In the present invention, a commercially available base material can be used, and for example, RC paper (manufactured by Mitsubishi Paper Industries Co., Ltd.) is preferable. The thickness of the substrate can be appropriately changed according to the strength and heat resistance required for the thermal transfer image-receiving sheet and the material of the material employed as the substrate. Specifically, the thickness of the substrate is It is preferably in the range of 50 μm to 1000 μm, and more preferably in the range of 100 μm to 300 μm.

Receiving layer The receiving layer in the present invention receives the sublimation dye transferred from the thermal transfer ink sheet during image formation by thermal transfer, and holds the received sublimation dye in the receiving layer, whereby an image is formed on the surface of the receiving layer. Can be formed and maintained. In the present invention, the receiving layer contains a binder resin, and may further contain a crosslinking agent, a hydrophilic binder, a release agent, and other additives.

  In the present invention, the receiving layer may be composed of two or more layers. In the case where the receiving layer is composed of two or more layers, the uppermost layer of the receiving layer may contain a hydrophilic binder, but the smaller the better, it is preferable that the receiving layer is substantially free. “Substantially free” means that the content of the hydrophilic binder is 1% by mass or less, preferably 0.1% by mass or less, and more preferably 0%, based on the solid content mass of the binder resin. 0.05% by mass or less, more preferably 0.01% by mass or less. The image density at the time of printing can be improved by reducing the amount of the hydrophilic binder contained in the uppermost layer of the receiving layer to the above level. Moreover, it is preferable that the film thickness at the time of drying of a receiving layer is 0.5-5.0 micrometers. If the film thickness at the time of drying is in this range, the coating suitability can be further improved.

The binder resin used to form the binder resin receiving layer includes acrylic resins, vinyl chloride resins, polyvinyl chloride resins, polyolefin resins such as polyethylene and polypropylene, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer resins ( Vinyl chloride resin), halogenated polymers such as polyvinylidene chloride, vinyl polymers such as polyvinyl acetate and polyacrylate, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, ethylene And copolymer resins of olefins such as propylene and other vinyl monomers, cellulose resins such as ionomers and cellulose diacetates, polycarbonates, and the like. Particularly preferred are vinyl chloride resins. In the present invention, commercially available binder resins can also be used. For example, VB603 (vinyl acetate resin) VB985 (vinyl chloride resin), VB900 (vinyl chloride acrylic resin), and sorbine C (aqueous dispersion, salt vinegar). Bi-based resin) (manufactured by Nissin Chemical Industry Co., Ltd.). Use of such a binder resin is preferable from the viewpoint of combination with the following crosslinking agent.

Crosslinking agent As the crosslinking agent used in the present invention, one containing an epoxy crosslinking agent having an epoxy equivalent of 300 or less, preferably 200 or less and 100 or more, and having a functional group number of 2 or more, preferably 4 or more and 10 or less. It is done. In addition, an epoxy equivalent (g / eq) is a value of the molecular weight of the epoxy crosslinking agent per functional group. Moreover, the functional group number is the number of epoxy groups in one molecule of the epoxy crosslinking agent. That is, it can be said that the smaller the epoxy equivalent and the greater the number of functional groups, the higher the crosslinking effect as a crosslinking agent. By using a crosslinking agent containing an epoxy crosslinking agent having a small epoxy equivalent and the number of functional groups within the above range, various performances such as burning performance, water resistance and image density can be improved. In the present invention, the epoxy group of the crosslinking agent reacts with the carboxyl group of the component in the coating layer to crosslink part or all of the resin, thereby improving various performances such as burning performance, water resistance, and image density. it can.

  In addition, when the present invention provides two or more layers containing hollow particles (for example, the following heat insulating layer and intermediate layer) in printing, particularly in printing in a high-temperature and high-humidity environment, A new mechanism has been discovered in which voids are generated on the boundary surface and irregularities are formed on the surface of the image receiving sheet, resulting in uneven printing. Therefore, as a result of diligent efforts, the present inventors added a specific epoxy cross-linking agent to any layer on the base material, so that the cross-linking agent component permeates and diffuses during the manufacturing process, thereby generating voids at the interface. And the surprising effect of increasing the smoothness of the image receiving sheet surface. Such an improvement in the smoothness of the surface of the image receiving sheet leads to an improvement in blurring performance (suppression of uneven printing).

  According to a preferred embodiment of the present invention, the content of the cross-linking agent is preferably 1 to 30% by mass, based on the total solid content mass of the resin (total of binder resin, hydrophilic binder, hollow particles and the like). Preferably it is 1-15 mass%, More preferably, it is 1-10 mass%. If the content of the crosslinking agent is in the above range, various performances such as burn performance, water resistance, and image density can be further improved. In the present invention, a commercially available epoxy crosslinking agent can also be used, and examples thereof include EX512, EX521, EX851, EX832 (above, Nagase ChemteX Corporation), CR5L (DIC Corporation), and the like. In addition, you may add the crosslinking agent containing said epoxy crosslinking agent to any one layer or more or all the layers (for example, a receiving layer, a heat insulation layer, and an intermediate | middle layer) in the receiving layer surface side of a base material.

Hydrophilic binder According to a preferred embodiment of the present invention, as the hydrophilic binder contained in the receiving layer, the following heat insulating layer and intermediate layer, gelatin and derivatives thereof, polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, pullulan, Mention may be made of carboxymethylcellulose, hydroxyethylcellulose, dextran, dextrin, polyacrylic acid and its salts, agar, κ-carrageenan, λ-carrageenan, ι-carrageenan, casein, xanthene gum, locust bean gum, alginic acid, and gum arabic. Particularly preferred is gelatin. By using such a hydrophilic binder, interlayer adhesion of each layer such as a receiving layer, a heat insulating layer, and an intermediate layer can be improved. In particular, when each layer is formed by an aqueous coating method and a simultaneous multilayer coating method, the suitability of coating can be improved by using gelatin. Moreover, the viscosity of each coating liquid can be adjusted to a desired range, and a desired film thickness can be obtained. In the present invention, commercially available gelatin can also be used, and for example, RR, R, CLV (manufactured by Nitta Gelatin Co., Ltd.) and the like are preferable.

Release Agent Examples of the release agent contained in the receiving layer in the present invention include silicone oil (including reaction curable silicone), phosphate plasticizers, and fluorine compounds, and silicone oil is particularly preferable. . Various silicones such as dimethyl silicone can be used as the silicone oil. Specifically, amino-modified silicone, epoxy-modified silicone, alcohol-modified silicone, vinyl-modified silicone, urethane-modified silicone, polyester-modified silicone, polyether-modified silicone, polyester-modified silicone oil, acrylic-modified silicone, amide-modified silicone, etc. It can also be polymerized using various reactions. Two or more release agents may be mixed and used. By using such a release agent, problems such as fusion between the thermal transfer ink sheet and the receiving layer of the thermal transfer image receiving sheet and a decrease in printing sensitivity during printing can be improved. In the present invention, it is particularly preferable to use a release agent of dimethyl silicone or polyether modified silicone type. Two or more of these release agents may be used, or may be used in combination with other release agents. In the present invention, commercially available release agents may be used, and for example, KF615A and KF352A (manufactured by Shin-Etsu Chemical Co., Ltd.), FZ2101 and SF8410 (manufactured by Toray Dow Corning Co., Ltd.) and the like are preferable.

Thermal insulation layer The thermal insulation layer in the present invention has thermal insulation and cushioning properties that can prevent heat applied during image formation by thermal transfer from being lost due to heat transfer to a substrate or the like. The heat insulation layer in the present invention contains hollow particles, and may further contain the above-mentioned crosslinking agent, the above-mentioned hydrophilic binder, and other additives. A heat insulation layer can be provided with cushioning properties by including hollow particles. Moreover, according to a preferable aspect, a heat insulation layer may consist of two or more layers. By providing two or more heat insulating layers in this way, the heat insulating properties and cushioning properties that affect the print quality and the adhesion to the substrate can be improved. Here, the degree of cushioning property of the heat insulating layer can be appropriately adjusted according to the application of the thermal transfer image receiving sheet. In addition, the degree of cushioning property of the heat insulating layer can be adjusted to an arbitrary range by changing the thickness of the heat insulating layer, for example. The thickness of the heat insulating layer is not particularly limited as long as the heat insulating property, cushioning property, and the like can be adjusted to a desired level. More preferably, it is within. The density of the thermal insulating layer, for example in the range of ^{0.1g / cm 3 ~0.8g / cm 3} , preferably in the range of inter alia ^{0.2g / cm 3 ~0.7g / cm 3} .

Hollow particles The volume average particle size of the hollow particles used in the present invention is preferably 0.1 to 10 µm, more preferably 0.3 to 5 µm. If the volume average particle diameter of the hollow particles is in the above range, heat insulating properties and cushioning properties can be imparted to the heat insulating layer. The average hollowness of the hollow particles is preferably 20% or more, more preferably 30 to 80%. If the average hollowness of the hollow particles is in the above range, heat insulating properties and cushioning properties can be imparted to the heat insulating layer. Furthermore, the organic hollow particle comprised from resin etc. may be sufficient, and the inorganic hollow particle comprised from glass etc. may be sufficient. The hollow particles may be cross-linked hollow particles. In the present invention, commercially available hollow particles can also be used. For example, HP-1055, HP-91, Ropeke SE (manufactured by Rohm and Haas Co., Ltd.), MH-5055 (Nippon Zeon) and the like are preferable.

Intermediate layer According to a preferred embodiment of the present invention, the intermediate layer exhibits a function as a primer layer. The primer layer has a function of adhering the heat-insulating layer and the receiving layer satisfactorily, and has a function of improving image storability by preventing migration of the dye to the heat-insulating layer side in a high-temperature and high-humidity environment. It is. In a preferred embodiment, the primer layer contains the hollow particles, the hydrophilic binder, and the binder resin, and the binder resin preferably contains an acrylic resin. Although it does not specifically limit as thickness of a primer layer, For example, it is preferable that they are 1 micrometer-40 micrometers, 1 micrometer-20 micrometers are more preferable, and 1 micrometer-10 micrometers are more preferable.

  In the present invention, the acrylic resin refers to a polymer of acrylic acid or methacrylic acid monomer or derivative thereof, a polymer of acrylic acid ester or methacrylic acid ester monomer or derivative thereof, acrylic acid or methacrylic acid monomer and other derivatives. It includes a copolymer with a monomer or a derivative thereof, and a copolymer of a monomer of an acrylate ester or a methacrylate ester with another monomer or a derivative thereof.

  According to a preferred embodiment of the present invention, the acrylic resin is preferably a copolymer of an acrylic ester or methacrylic ester monomer and another monomer or a derivative thereof. Examples of the acrylic acid ester or methacrylic acid ester monomer include alkyl acrylate and alkyl methacrylate, preferably methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, lauryl acrylate, and lauryl methacrylate. Can be mentioned. Examples of other monomers include aromatic hydrocarbons, aryl group-containing compounds, amide group-containing compounds, and vinyl chloride, preferably styrene, benzylstyrene, phenoxyethyl methacrylate, acrylamide, and methacrylamide. it can. In the present invention, a copolymer of an alkyl acrylate or an alkyl methacrylate and at least one other monomer selected from the group consisting of an aromatic hydrocarbon, an aryl group-containing compound, and an amide group-containing compound, or a derivative thereof. It is particularly preferable to use it. By copolymerizing the monomers as described above, the concentration and releasability can be improved. Two or more acrylic resins may be mixed and used.

Release layer In the present invention, the release agent may not be added to the receiving layer, but may be provided as a separate release layer on the receiving layer.

Other Layers In the present invention, other layers may be provided in addition to the above heat insulating layer, receiving layer, intermediate layer, and release layer. By providing other layers, functions such as solvent resistance, dye diffusion barrier during image storage under high temperature / high humidity, interlayer adhesion, whitening, glare / unevenness of the substrate, and antistatic functions Can be added. Known means can be used as the means for forming the other layers. For example, fluorescent brighteners, inorganic fine particles, hollow fine particles, and organic conductive materials such as conductive fillers and polyaniline sulfonic acid, etc. The method of adding is mentioned.

Manufacturing Method of Thermal Transfer Image Receiving Sheet A known manufacturing method can be used for manufacturing the thermal transfer image receiving sheet of the present invention. For the application of each layer of the thermal transfer image-receiving sheet, a known method such as roll coating, bar coating, gravure coating, gravure reverse coating, die coating, slide coating, curtain coating, etc. can be used. A method in which these layers can be applied simultaneously is preferred. In the present invention, all layers constituting the receiving layer from the heat insulating layer are formed by an aqueous coating method and a simultaneous multi-layer coating method, so that there are effects such as improvement of interlayer adhesion of each layer of the thermal transfer image-receiving sheet and cost improvement. can get.

  According to a preferred aspect of the present invention, the method for producing a thermal transfer image-receiving sheet of the present invention may further include a setting step and a drying step after forming a receiving layer and other layers on a substrate by coating. Good. The setting step referred to in the present invention means, for example, increasing the viscosity of the coating composition by means of, for example, blowing cold air or the like onto the coating surface on the support to lower the temperature, and the material fluidity between each layer and each layer. It is a process of promoting gelation that slows down. The temperature condition when using cold air is preferably 25 ° C. or less, and more preferably 10 ° C. or less. Further, the time for which the coating film is exposed to cold air is preferably 10 seconds or more and 120 seconds or less, although it depends on the coating conveyance speed.

Thermal transfer ink sheet The thermal transfer ink sheet used together with the thermal transfer image-receiving sheet of the present invention is provided with a heat transferable color material layer on one side of the base sheet and a heat resistant slipping layer on the other side of the base sheet. It is preferable to have a layer structure. Hereinafter, each layer constituting the thermal transfer ink sheet will be described.

As the material of the base sheet constituting the thermal transfer ink sheet used in the present invention, a conventionally known material can be used, and even if it is other than that, it has a certain degree of heat resistance and strength. Can be used. For example, polyethylene terephthalate, polyester, polypropylene, polycarbonate, polyethylene, polystyrene, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyimide, nylon, cellulose acetate, ionomer and other resin films, condenser paper, paraffin paper, and other non-woven fabrics Etc. These may be used alone, or a laminate in which these are arbitrarily combined may be used. Among these, polyethylene terephthalate which is a versatile plastic that can be thinned and is inexpensive is preferable.

  The thickness of the base sheet can be appropriately selected according to the material so that the strength, heat resistance and the like are appropriate, but is usually preferably about 0.5 to 50 μm, more preferably 1 to 20 μm, and further Preferably it is 1-10 micrometers.

  The base sheet may be subjected to a surface treatment in order to improve adhesion with an adjacent layer. As the surface treatment, known resin surface modification techniques such as corona discharge treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, surface roughening treatment, chemical treatment, plasma treatment, and grafting treatment are applied. can do. Only one type of the surface treatment may be applied, or two or more types may be applied.

  Furthermore, it is also possible to apply and form an adhesive layer on the base sheet as an adhesive treatment of the base sheet. An adhesion layer can be formed from the following organic materials and inorganic materials, for example. Examples of the organic material include polyester resins, polyacrylate resins, polyvinyl acetate resins, polyurethane resins, styrene acrylate resins, polyacrylamide resins, polyamide resins, polyether resins, polystyrene resins, Examples thereof include polyethylene resins, polypropylene resins, polyvinyl chloride resins, polyvinyl alcohol resins, polyvinyl pyrrolidone and vinyl resins such as modified products thereof, and polyvinyl acetal resins such as polyvinyl acetoacetal and polyvinyl butyral. Examples of the inorganic material include silica (colloidal silica), alumina or alumina hydrate (alumina sol, colloidal alumina, cationic aluminum oxide or hydrate, suspicion bakumaite, etc.), aluminum silicate, magnesium silicate, magnesium carbonate, oxidation Examples thereof include ultrafine particles of colloidal inorganic pigments such as magnesium and titanium oxide.

  Moreover, when manufacturing a plastic film by extending | stretching as said surface treatment, a primer liquid can be apply | coated to an unstretched film and it can also carry out by extending | stretching after that (primer process).

Thermal transferable color material layer The thermal transfer ink sheet used in the present invention is provided with a thermal transferable color material layer on one surface of a substrate sheet. When the thermal transfer ink sheet is a sublimation type thermal transfer ink sheet, a layer containing a sublimation dye is formed as the thermal transferable color material layer, and when the thermal transfer type thermal transfer ink sheet is a hot melt composition containing a colorant A layer containing a heat-meltable ink is formed. A layer region containing a sublimable dye and a layer region containing a heat-meltable ink composed of a heat-melting composition containing a colorant are provided in a surface sequence on a continuous base sheet. Also good.

  As the material of the heat transferable color material layer, conventionally known dyes can be used, but those having good characteristics as a printing material, for example, having a sufficient coloring density and changing color due to light, heat, temperature, etc. Those that do not are preferred. For example, as a red dye, MS Red G (manufactured by Mitsui Toatsu Chemical Co., Ltd.), Macrolex Red Violet R (manufactured by Bayer), CeresRed 7B (manufactured by Bayer), Samalon Red F3BS (manufactured by Mitsubishi Chemical), etc. are yellow. Examples of the dye include Holon Brilliant Yellow 6GL (manufactured by Clariant), PTY-52 (manufactured by Mitsubishi Kasei Co., Ltd.), Macrolex Yellow 6G (manufactured by Bayer), etc., and examples of the blue dye include Kayaset Blue 714 (Nippon Kayaku Co., Ltd.). Manufactured), Waxoline Blue AP-FW (manufactured by ICI), Holon Brilliant Blue SR (manufactured by Sand), MS Blue 100 (manufactured by Mitsui Toatsu Chemicals) and the like.

  Examples of the binder resin for supporting the dye include cellulose resins such as ethyl cellulose resin, hydroxyethyl cellulose resin, ethyl hydroxy cellulose resin, methyl cellulose resin, and cellulose acetate resin, polyvinyl alcohol resin, polyvinyl acetate resin, and polyvinyl butyral resin. And vinyl resins such as polyvinyl acetal resin and polyvinyl pyrrolidone, acrylic resins such as poly (meth) acrylate and poly (meth) acrylamide, polyurethane resins, polyamide resins, and polyester resins. Among these, cellulose-based, vinyl-based, acrylic-based, polyurethane-based, and polyester-based resins are preferable from the viewpoints of heat resistance, dye transferability, and the like.

  Examples of the method for forming the heat transferable color material layer include the following methods. For the heat-transferable colorant layer obtained by adding additives such as a release agent to the above dyes and binder resin, if necessary, dissolved in an appropriate organic solvent such as toluene or methyl ethyl ketone, or dispersed in water. A coating solution (solution or dispersion) is applied to one surface of a base sheet by, for example, a gravure printing method, a reverse roll coating method using a gravure plate, a roll coater, a bar coater, etc. It can be formed by drying. The heat transferable color material layer has a thickness of about 0.2 to 5.0 μm, and the content of the sublimable dye in the heat transferable color material layer is 5 to 90% by weight, preferably 5 to 70% by weight. It is preferable that

Protective layer The thermal transfer ink sheet used in the present invention may be provided with a protective layer in the surface order on the same side as the thermal transferable color material layer. After the color material is transferred to the thermal transfer image-receiving sheet, the protective layer is transferred to cover the image, whereby the image can be protected from light, gas, liquid, abrasion and the like. Other layers such as an adhesive layer, a release layer, a release layer, or an undercoat layer may be provided as a protective layer.

Heat-resistant slip layer The heat-resistant slip layer is mainly composed of a heat-resistant resin. The heat resistant resin is not particularly limited. For example, polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride-vinyl acetate copolymer resin, polyether resin, polybutadiene resin, styrene-butadiene copolymer resin, Acrylic polyol, polyurethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, urethane or epoxy prepolymer, nitrocellulose resin, cellulose nitrate resin, cellulose acetate propionate resin, cellulose acetate butyrate resin, cellulose acetate-hydrodiene Phthalate resin, cellulose acetate resin, aromatic polyamide resin, polyimide resin, polyamideimide resin, polycarbonate resin, Fine chlorinated polyolefin resins.

  The heat resistant slipping layer may be formed by blending additives such as a slipperiness imparting agent, a crosslinking agent, a release agent, an organic powder, and an inorganic powder in addition to the above heat resistant resin.

  In general, the heat-resistant slipping layer is formed by adding the above-mentioned heat-resistant resin, and the above-described slipperiness-imparting agent and additives that are optionally added to the solvent, and dissolving or dispersing each component to thereby apply the heat-resistant slipping layer coating solution. Then, the heat resistant slipping layer coating solution can be coated on a substrate and dried. As the solvent in the heat resistant slipping layer coating solution, the same solvent as that in the dye ink can be used.

Examples of the coating method of the heat resistant slipping layer coating liquid include wire bar coating, gravure printing, screen printing, reverse roll coating using a gravure plate, and gravure coating is particularly preferable. Heat-resistant slip layer coating solution, dry coating amount is preferably 0.1 to 3 g / ^{m 2,} more preferably may be applied so as to be 1.5 g / ^{m 2} or less.

Image Forming Method In the image forming method using the thermal transfer image receiving sheet of the present invention, the thermal transfer image receiving sheet and the thermal transfer ink sheet containing a heat diffusible dye are overlaid and heated in accordance with a recording signal, thereby transferring the thermal transfer image. An image can be formed by transferring the thermal diffusible dye contained in the ink sheet to the thermal transfer image-receiving sheet.

  As a thermal transfer recording apparatus that can be used in such an image forming method, a known apparatus can be used and is not particularly limited. In the present invention, a commercially available thermal transfer recording apparatus can be used, and examples include a sublimation thermal transfer printer (manufactured by ALTECH ADS, model: MEGAPIXEL III).

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not construed as being limited to the contents of the following examples. In addition, the weight part of description was described by solid content, it diluted using the pure water, and it adjusted so that the total solid content of each coating liquid might be 15-30%.

Example 1
Preparation of thermal transfer image-receiving sheet 1 Using RC paper (manufactured by Mitsubishi Paper Industries Co., Ltd.) as a base sheet, heat-treating coating solution 1 for heat-insulating layer and coating solution 1 for receiving layer having the following compositions were heated to 40 ° C., respectively, and slide coating Was applied so that the thickness during drying would be 12 μm and 3 μm, respectively, cooled at 5 ° C. for 30 seconds, then dried at 50 ° C. for 2 minutes, and heat transfer image-receiving sheet 1 (layer constitution: substrate / A heat insulating layer / receiving layer) was obtained.

Composition of coating solution 1 for heat insulation layer MH5055 (hollow particles, manufactured by Nippon Zeon Co., Ltd., volume average particle size 0.5 μm) 70 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 25 parts by weight AP40 (Water-based polyurethane resin, manufactured by DIC Corporation) 5 parts by weight
Composition of Receptive Layer Coating Solution 1 VB603 (vinyl chloride resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 10 parts by weight KF615A (polyether) Modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight · EX512 (epoxy crosslinking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight

Example 2
Preparation of thermal transfer image-receiving sheet 2 RC paper (manufactured by Mitsubishi Paper Industries Co., Ltd.) is used as a base sheet, and coating liquid 2-2 for heat insulation layer (for lower layer) and coating liquid 2-1 for heat insulation layer (upper layer) having the following composition: ), Intermediate layer coating solution, receptor layer coating solution 2-2 (for lower layer), and receptor layer coating solution 2-1 (for upper layer) were each heated to 40 ° C. and dried using slide coating. The coatings were coated so that the thicknesses were 2 μm, 12 μm, 3.5 μm, 1.5 μm, and 3 μm, respectively, cooled at 5 ° C. for 30 seconds, dried at 50 ° C. for 2 minutes, and heat-transfer image-receiving sheet 2 (layer Structure: Substrate / heat insulating layer (lower layer) / heat insulating layer (upper layer) / intermediate layer / receiving layer (lower layer) / receiving layer (upper layer)) was obtained.
Composition of coating solution 2-2 for heat insulating layer (for lower layer) MH5055 (hollow particles, manufactured by Nippon Zeon Co., Ltd., volume average particle size 0.5 μm) 60 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) ) 20 parts by weight DM820 (MBR, manufactured by DIC Corporation) 20 parts by weight
Composition of coating solution 2-1 for heat insulation layer (for upper layer) MH5055 (hollow particles, manufactured by Nippon Zeon Co., Ltd., volume average particle size 0.5 μm) 70 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) ) 25 parts by weight / AP40 (aqueous polyurethane resin, manufactured by DIC Corporation) 5 parts by weight
Composition of coating solution for intermediate layer SX866 (crosslinked hollow particles, JSR Corporation, volume average particle size 0.1 μm, porosity 30%) 70 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 15 parts by weight・ NKJ300 (methacrylic acid ester / acrylic copolymer, Shin-Nakamura Chemical Co., Ltd.)
15 parts by weight
Composition of coating liquid 2-2 for receiving layer (for lower layer) VB603 (vinyl chloride resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 10 weight Part
Composition of receiving layer coating solution 2-1 (for upper layer) VB603 (vinyl acetate resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight KF615A (polyether-modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) ) 10.5 parts by weight · EX512 (epoxy crosslinking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight

Example 3
Preparation of thermal transfer image-receiving sheet 3 A thermal transfer image-receiving sheet 3 was prepared in the same manner as in Example 2 except that the composition of the coating solution for the receiving layer (for the upper layer) and the coating solution for the heat insulating layer (for the upper layer) was as follows. .
Composition of coating solution 3-1 (for upper layer) for heat insulation layer MH5055 (hollow particles, manufactured by Nippon Zeon Co., Ltd., volume average particle size 0.5 μm) 70 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) ) 25 parts by weight · AP40 (aqueous polyurethane resin, manufactured by DIC Corporation) 5 parts by weight · EX512 (epoxy crosslinking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight
Composition of coating solution 3-1 for upper layer (for upper layer) VB603 (vinyl acetate resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight KF615A (polyether modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight

Example 4
Preparation of thermal transfer image-receiving sheet 4 A thermal transfer image-receiving sheet 4 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of coating solution 4 for receiving layer: VB603 (vinyl acetate resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight KF615A (polyether-modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight・ EX512 (epoxy crosslinking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight

Example 5
Preparation of thermal transfer image-receiving sheet 5 A thermal transfer image-receiving sheet 5 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of coating solution 5 for receiving layer • VB985 (vinyl chloride resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight • RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 10 parts by weight • KF615A (polyether-modified silicone) 10.5 parts by weight, manufactured by Shin-Etsu Chemical Co., Ltd.) EX512 (epoxy crosslinking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight

Example 6
Preparation of Thermal Transfer Image Receiving Sheet 6 A thermal transfer image receiving sheet 6 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of coating solution 6 for receiving layer • VB900 (vinyl chloride resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight • RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 10 parts by weight • KF615A (polyether modified) Silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight EX512 (epoxy crosslinking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight

Example 7
Preparation of thermal transfer image-receiving sheet 7 A thermal transfer image-receiving sheet 7 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of coating solution 7 for receiving layer: Solvain C (aqueous dispersion, vinyl acetate resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 10 parts by weight -KF615A (polyether-modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight-EX512 (epoxy cross-linking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight It was used in the state of a dispersion dispersed in 1.

Example 8
Preparation of thermal transfer image receiving sheet 8 A thermal transfer image receiving sheet 8 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of coating solution 8 for receiving layer: VB603 (vinyl acetate resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 10 parts by weight KF615A (polyether) Modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight, EX521 (epoxy crosslinking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight

Example 9
Preparation of thermal transfer image receiving sheet 9 A thermal transfer image receiving sheet 9 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of coating solution 9 for receiving layer: VB603 (vinyl acetate resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 10 parts by weight KF615A (polyether) Modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight • EX851 (epoxy crosslinking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight

Example 10
Preparation of thermal transfer image-receiving sheet 10 A thermal transfer image-receiving sheet 10 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of receiving layer coating solution 10 VB603 (vinyl chloride resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 10 parts by weight KF615A (polyether) Modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight • CR5L (epoxy crosslinking agent, manufactured by DIC Corporation) 5 parts by weight

Example 11
Preparation of thermal transfer image receiving sheet 11 A thermal transfer image receiving sheet 11 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of coating solution 11 for receiving layer: VB603 (vinyl acetate resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 10 parts by weight KF615A (polyether) Modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight • EX832 (epoxy crosslinking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight

Comparative Example 1
Preparation of Thermal Transfer Image Receiving Sheet 12 A thermal transfer image receiving sheet 12 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of coating solution 12 for receiving layer: VB603 (vinyl acetate resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight, RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.), 10 parts by weight, KF615A (polyether) Modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight · K2030E (oxazoline group-containing polymer-based crosslinking agent, manufactured by Nippon Shokubai Co., Ltd.) 5 parts by weight

Comparative Example 2
Preparation of thermal transfer image-receiving sheet 13 A thermal transfer image-receiving sheet 13 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of coating solution 13 for receiving layer: VB603 (vinyl acetate resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 10 parts by weight KF615A (polyether) Modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight • EX841 (epoxy crosslinking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight

Comparative Example 3
Preparation of Thermal Transfer Image Receiving Sheet 14 A thermal transfer image receiving sheet 14 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of coating solution 14 for receiving layer: VB603 (vinyl acetate resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight RR (gelatin, manufactured by Nitta Gelatin Co., Ltd.) 10 parts by weight KF615A (polyether) Modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.5 parts by weight • EX145 (epoxy crosslinking agent, manufactured by Nagase ChemteX Corporation) 5 parts by weight

Table 1 shows the epoxy equivalent and the number of functional groups of the epoxy crosslinking agents used in Examples 1 to 11 and Comparative Examples 1 to 3.

Evaluation of Thermal Transfer Image Receiving Sheet For the thermal transfer image receiving sheets 1 to 14 prepared above, (1) Burn performance evaluation, (2) Adhesion evaluation, (3) Water resistance evaluation, (4) Moisture resistance and heat bleeding evaluation, and (5 ) Image density evaluation was performed.

(1) Burn performance evaluation The thermal transfer image-receiving sheet prepared above, a sublimation thermal transfer printer (manufactured by ALTECH ADS, model: MEGAPIXEL III), and the genuine ink ribbon of the printer are used in a high-temperature and high-humidity environment (40 degrees 85%). Etc.) was allowed to stand for 3 hours so that no dew condensation (according), and then a solid black image was printed in that environment, and the burnt level was visually evaluated. In the present invention, “burn” means that the image density is uneven due to roughness or unevenness on the surface of the image receiving paper. This is particularly noticeable in a black solid image.
Evaluation criteria 5: Density unevenness did not occur in the solid black print.
4: Density unevenness occurred in an area of less than 20% of the entire print area of the black solid print.
3: Density unevenness occurred in an area of 20% or more and less than 50% of the entire print area of the black solid print.
2: Density unevenness occurred in an area of 50% or more and less than 75% of the entire print area of the black solid print.
1: Density unevenness occurred in an area of 75% or more of the entire print area of the black solid print.

(2) Adhesive evaluation A mending tape (manufactured by Nichiban Co., Ltd.) 12 mm wide industrial mending tape was attached to the thermal transfer image-receiving sheet prepared above, and a 90-degree peel test was performed. The evaluation criteria of the tape adhesion test are as follows.
Evaluation criteria 5: No destruction was observed on the thermal transfer image-receiving sheet, and no adhesion was observed on the mending tape.
4: Although no breakage was observed in the thermal transfer image-receiving sheet, a very small amount of coloring matter was adhered in the microscopic observation of the mending tape.
3: The thermal transfer image-receiving sheet was broken, and a layer having an area of less than 20% of the entire sticking area was adhered to the mending tape.
2: The thermal transfer image-receiving sheet was broken, and a layer having an area of 20% or more and less than 50% of the entire pasting area was adhered to the mending tape.
1: The thermal transfer image-receiving sheet was destroyed, and a layer having an area of 50% or more of the entire sticking region was adhered to the mending tape.

(3) Water resistance evaluation The thermal transfer image-receiving sheet prepared above is immersed in warm water heated to 36 degrees for 1 minute, taken out from the warm bath, and excess water is allowed to flow off. 30 seconds after the removal, a scratch test was performed with a HEIDON measuring instrument with a load of 20 g and a 0.5 mmφ needle, and the water resistance was evaluated based on the width of the scratch. The evaluation criteria are as follows.
Evaluation criteria 5: There were no scratches.
4: There were scratches with a width of 200 μm or less.
3: There were scratches with a width of 200 μm or more and less than 300 μm.
2: There were scratches having a width of 300 μm or more and less than 500 μm.
1: There was a scratch having a width of 500 μm or more. Alternatively, the coating layer was dissolved in water.

(4) Moisture resistance and heat bleed evaluation A 0.5 mm-wide linear image (black) is printed on the thermal transfer image-receiving sheet produced above using a sublimation thermal transfer printer (manufactured by ALTECH ADS, model: MEGAPICEL III), and then printed. Although the product was stored in an environment of 60 ° C. Free and 40 ° C. and 90% for one week, the image blur was visually evaluated.
-Evaluation criteria 5: It was not blurred.
4: When I looked closely, the line was slightly blurred.
3: The line was clearly blurred.
2: The line was blurred due to blurring.
1: The line was completely blurred and could not be confirmed as the original line.

(5) Image Density Evaluation A sublimation thermal transfer printer (manufactured by ALTECH ADS, model: MEGAPICEL III) and an ink ribbon (for Megapixel III, Altech AD Co., Ltd. genuine product) are applied to the thermal transfer image receiving sheet prepared above. Using this, an 18 gradation gradation image having an RGB value of 15 × n (n = 0 to 17) is printed, and the optical reflection density by an optical densitometer (spectrolino manufactured by Gretag Macbeth) (Ansi-A, D65)) The maximum value was measured to show the OD value (optical density) of black.

Table 2 shows the results of the above evaluations. The thermal transfer image-receiving sheets of Examples 1 to 11 satisfying the composition of the present invention are compared with the thermal transfer image-receiving sheets of Comparative Examples 1 to 3, and the burned performance, adhesion, water resistance, moisture resistance and heat resistance of the printed matter, and It can be seen that each performance of image density was improved.

Claims (8)

A thermal transfer image-receiving sheet having a base material and a heat insulating layer and a receiving layer on the base material,
The heat insulating layer includes hollow particles;
The receiving layer includes a binder resin;
The heat-insulating layer and / or the receiving layer, gelatin, formed by a crosslinking agent and a including a coating solution,
The crosslinking agent includes an epoxy crosslinking agent having an epoxy equivalent of 300 or less and a functional group number of 2 or more,
The thermal transfer image-receiving sheet , wherein the content of the crosslinking agent is 1 to 30% by mass with respect to the total solid content mass of the resin .   The thermal transfer image receiving sheet according to claim 1, wherein the receiving layer contains a crosslinking agent.   The thermal transfer image-receiving sheet according to claim 1 or 2, wherein the binder resin contained in the receiving layer is a vinyl acetate resin.   The thermal transfer according to any one of claims 1 to 3, wherein the receiving layer comprises two or more receiving layers, and the uppermost layer of the two or more receiving layers does not substantially contain a hydrophilic binder. Image receiving sheet.   The thermal transfer image receiving sheet according to claim 4, wherein the hydrophilic binder is gelatin.   The thermal transfer image receiving sheet according to any one of claims 1 to 5, further comprising an intermediate layer between the heat insulating layer and the receiving layer.   The thermal transfer image-receiving sheet according to any one of claims 1 to 6, wherein all layers constituting the receiving layer from the heat insulating layer are formed by an aqueous coating method and a simultaneous multilayer coating method. A method for producing a thermal transfer image-receiving sheet according to any one of claims 1 to 7,
A method for producing a thermal transfer image receiving sheet, wherein all layers constituting the receiving layer from the heat insulating layer are formed by an aqueous coating method and a simultaneous multilayer coating method.