JP5660449B2 - Method for producing thermal transfer image-receiving sheet - Google Patents

Description

  The present invention relates to a base material and a method for producing a thermal transfer image-receiving sheet having a heat insulating layer and a receiving layer on the base material.

  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, various studies have been made on the coating liquid for forming the receiving layer of the thermal transfer image-receiving sheet according to the performance of the receiving layer and the manufacturing method. In particular, since it is preferable to use an aqueous coating solution from the viewpoints of the environment and the like, various methods have been proposed. For example, it has been proposed to form a receiving layer using a coating solution containing vinyl chloride, gelatin, and a silicone compound having an amino group or an epoxy group (see, for example, Patent Document 1). It has also been proposed to form a receiving layer using a water-soluble gelatin dispersion containing polyester (see, for example, Patent Document 2). As for the method for producing an aqueous dispersion, it has been proposed to disperse an acid-modified polyolefin or polyarate resin in an aqueous medium (for example, see Patent Documents 3 and 4).

  However, development of a thermal transfer image-receiving sheet excellent in various properties such as releasability, moisture resistance / heat resistance, and image density of printed matter is still desired.

JP2008-6781 JP-A-8-90938 JP2009-79078 JP2010-18770

  The present invention has been made in view of the above-described background art, and its purpose is to provide a method for producing a thermal transfer image-receiving sheet excellent in various properties such as releasability, moisture resistance / heat resistance, and image density of a printed matter. There is to do. In particular, it is to improve the performance of a receiving layer formed using an aqueous dispersion coating solution.

  In order to solve the above-mentioned problems, the present inventors have intensively studied. As a result, in a method for producing a thermal transfer image-receiving sheet having a heat insulating layer and a receiving layer in this order on a substrate, To find out that the above problem can be solved by forming a receiving layer using an aqueous dispersion coating solution containing a resin and a solvent-based mold release agent and substantially free of gelatin, to complete the present invention. It came.

That is, according to one aspect of the present invention,
A method for producing a thermal transfer image receiving sheet, comprising a base material, and a heat insulating layer and a receiving layer in this order on the base material,
Using an aqueous coating solution containing hollow particles, forming a heat insulating layer on the substrate;
A solvent-based solution comprising a solvent-based polyvinyl chloride resin and a solvent-based mold release agent is received on the heat insulating layer using an aqueous dispersion coating solution obtained by emulsifying an aqueous solution substantially free of gelatin. A method of manufacturing a thermal transfer image-receiving sheet, comprising the step of forming a layer.

  According to the method for producing a thermal transfer image receiving sheet of the present invention, it is possible to provide a thermal transfer image receiving sheet excellent in various properties such as releasability, moisture resistance / heat resistance, and image density of printed matter. In particular, the performance of the receiving layer formed using the aqueous dispersion coating solution can be improved. In addition, the migration of the solvent-based polyvinyl chloride resin to the heat insulating layer can be suppressed, the dissolution of the hollow particles contained in the heat insulating layer into the solvent can be prevented, and the performance degradation of the hollow particles can be avoided. Therefore, it is not necessary to provide an intermediate layer such as a barrier layer between the heat insulating layer and the receiving layer, so that the cost can be improved.

It is a schematic cross section which shows an example of the thermal transfer image receiving sheet manufactured by the manufacturing method of this invention.

Thermal transfer image-receiving sheet The thermal transfer image-receiving sheet of the present invention comprises a base material, and at least a heat insulating layer and a receiving layer on the base material in this order. In a preferred embodiment, the thermal transfer image receiving sheet may further have other layers.

  According to one aspect of the present invention, there is provided a thermal transfer image receiving sheet comprising a heat insulating layer and a receiving layer in this order on a substrate. Specifically, FIG. 1 shows a schematic sectional view of an example of the thermal transfer image receiving sheet according to the present invention. A thermal transfer image receiving sheet 10 shown in FIG. 1 has a base material 11, a heat insulating layer 12, and a receiving layer 13 on the base material 11 in this order.

The base material in the present invention has a role of holding the receiving layer and heat is applied at the time of thermal transfer. Therefore, the base material may be a material having a mechanical strength that does not hinder handling even in a heated 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 preferred. 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.

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 insulating layer in the present invention contains hollow particles, and may further contain a 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.

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. The receptor layer in the present invention is formed by an aqueous dispersion coating solution.

The aqueous dispersion coating liquid used for forming the aqueous dispersion coating liquid receiving layer can be prepared by dispersing a solvent-based polyvinyl chloride resin and a solvent-based release agent by a conventionally known method. For example, it is desirable to disperse and prepare an aqueous solution containing a dispersant and a solvent-based solution containing a solvent-based polyvinyl chloride resin and a solvent-based release agent by a method such as a homogenizer. In the present invention, the “aqueous solution” is a solution using water as a medium, and the “solvent solution” is a solution using an organic solvent as a medium. A dispersion containing a solvent-based polyvinyl chloride resin and a solvent-based release agent can be formed by separately preparing an aqueous solution and a solvent-based solution, and then mixing and dispersing the mixture using a homogenizer or the like. . The dispersion may be substantially free of the following gelatin, and may further include additives as appropriate. In the present invention, the receiving layer may be substantially free of gelatin. In the present invention, “substantially free” means that no gelatin is intentionally added to modify the properties of the receiving layer. For example, the gelatin content is 1% by mass or less, preferably 0.1% by mass or less, more preferably 0.05% by mass or less, based on the solid content mass of the polyvinyl chloride resin. More preferably, it is 0.01 mass% or less. By reducing the amount of gelatin contained in the receiving layer to the above level, the image density at the time of printing can be improved.

Examples of the dispersant used for the preparation of the dispersant aqueous solution include those selected from the group consisting of anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and mixtures thereof. It is done. From the viewpoint of preventing “bleeding” of an image, a sulfonic acid type anionic surfactant is more preferable. A low molecular surfactant has good dispersibility, and among them, a low molecular anionic surfactant is particularly good. In addition, high-molecular surfactants and nonionic surfactants with high HLB have good dispersion stability. Stability can be further increased by using in combination with low and high molecular surfactants. For example, sodium dodecylbenzenesulfonate, sodium tetradecylbenzenesulfonate, di-t-butylnaphthalenesulfonate, sodium triisopropylnaphthalenesulfonate, mononaphthalenesulfonate, p-nonylphenoxypropylsulfonate Na salt, Na salt of dodecyl sulfonic acid, Na salt of perfluorooctane sulfonic acid, Na salt of bis-2-ethylhexyl sulfosuccinic acid, Na salt of diisooctyl sulfosuccinic acid, Di (1,1,7-trihydro-perfluoroheptyl) sulfosuccinic acid Acid Na salt, stearic acid Na salt, 2-methyl-hexanol sulfonic acid Na salt, heptadecenylbenzimidazole sulfonic acid Na salt, N-methyloleyl tauride Na salt, N-perfluorooctyl sulfonyl N- propyl glycine K salts, sorbitan lauryl monoester, alkyl naphthalene sulfonate Na, succinic dioctyl sulfonic acid Na, polyoxyethylene - polyoxypropylene condensate, polyoxyethylene lauryl ether sulfate Na and the like. By using such a dispersant, an aqueous dispersion coating liquid containing a polyvinyl chloride resin and the following solvent-based release agent can be in a stable state. In the present invention, commercially available dispersants can also be used. For example, Hightenol, Neogen LA-10, Neogen LA-12, PSA-C, Eocol SW, Hightenol LA- manufactured by Daiichi Kogyo Seiyaku Co., Ltd. 10, Prisurf DB-01, Epan 485, Epan 785, Adeka LA LA-50, Adeka Pluronic F-68, Adeka Pluronic F-88, Adeka Pluronic F-108, Adeka Hope YES-25, etc. from ADEKA Corporation are preferable.

The organic solvent used in the preparation of the organic solvent solvent-based solution may be any solvent that dissolves the solvent-based resin and silicone, such as an aromatic hydrocarbon solvent such as ethyl acetate, toluene or benzene, or a ketone solvent such as acetone or methyl ethyl ketone. Those selected from the group consisting of solvents, and mixtures thereof. By using such an organic solvent, it is possible to increase dispersibility and maintain an appropriate dispersion state with water. Thereby, an aqueous dispersion coating solution for the receiving layer can be obtained. In this invention, you may put the process of removing an organic solvent by means, such as a heating and / or pressure reduction, after dispersion | distribution or simultaneously with dispersion | distribution.

Polyvinyl chloride resin The resin used in the present invention is a polyvinyl chloride resin, which may be copolymerized with a general resin, and is preferably a copolymer with vinyl acetate (vinyl chloride resin). In the present invention, the “polyvinyl chloride resin” preferably contains vinyl chloride at a composition ratio (molar ratio) of 50% or more of the whole. Various properties such as solubility, adhesion, and chemical resistance can be changed depending on the molar ratio of vinyl chloride and vinyl acetate, the degree of polymerization, the molecular weight, and the like. By using a polyvinyl chloride resin for the preparation of the aqueous dispersion, it is possible to obtain good printability after coating while the dispersion containing the polyvinyl chloride resin and the solvent release agent is in a stable state. . In the present invention, commercially available vinyl chloride-based resins can also be used. For example, Nisshin Chemical Industry Co., Ltd. Solvain C, Solvain CL, Solvain CH, Solvine CN, Solvine CNL, Solvine A, Solvain AL, Solvein TA2, Solvein TA3, and the like are preferable.

Solvent-based release agent Examples of the solvent-based release agent used for the preparation of the solvent-based solution include solvent-based silicones and fluorine-based surfactants, and solvent-based silicones are particularly preferable. As the solvent-based silicone, various modified silicones such as dimethyl silicone can be used. 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. These may be used as a mixture, or may be polymerized using various reactions. Two or more release agents may be mixed and used. By forming a receiving layer using such an aqueous dispersion coating solution containing 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 are improved. Can do. In the present invention, a commercially available solvent-based mold release agent can also be used, for example, X-22-163, X-22-173D, X-22-343, X-22-2000 manufactured by Shin-Etsu Chemical Co., Ltd. X-22-3000T, KF-101, KF-102, KF-1001, KF-1002, KP-1800U, X-22-4015, X-22-1660B, X-22-160ASD, KF-410, etc. preferable.

Other layers In the present invention, other layers may be provided in addition to the heat insulating layer and the receiving 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.

Hydrophilic binder According to a preferred embodiment of the present invention, a hydrophilic binder can be used in the aqueous solution used for forming the heat insulating layer and other layers. Examples of hydrophilic binders include gelatin and derivatives thereof, polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, pullulan, carboxymethyl cellulose, hydroxyethyl cellulose, dextran, dextrin, polyacrylic acid and salts thereof, agar, κ-carrageenan, and λ-carrageenan. , Iota-carrageenan, casein, xanthene gum, locust bean gum, alginic acid, and gum arabic, with gelatin being particularly preferred. By using such a hydrophilic binder, interlayer adhesion with the heat insulating layer and other layers can be improved. In particular, when each layer is formed by an aqueous coating method and a simultaneous multilayer coating method, by using gelatin, the viscosity of each coating solution 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.

Manufacturing method of thermal transfer image receiving sheet The manufacturing method of the thermal transfer image receiving sheet of the present invention is:
Forming a heat insulating layer on the substrate using an aqueous coating solution containing hollow particles;
A solvent-based solution comprising a solvent-based polyvinyl chloride resin and a solvent-based mold release agent is received on the heat insulating layer using an aqueous dispersion coating solution obtained by emulsifying an aqueous solution substantially free of gelatin. Forming a layer. In this way, by forming the receptor layer on the heat insulation layer using the aqueous dispersion coating liquid, the transition of the solvent-based polyvinyl chloride resin to the heat insulation layer is suppressed, and the hollow particles contained in the heat insulation layer Can be prevented from being dissolved in the solvent, and the deterioration of the performance of the hollow particles can be avoided. Therefore, it is not necessary to provide an intermediate layer such as a barrier layer between the heat insulating layer and the receiving layer, so that the cost can be improved. Further, in the present invention, since the receiving layer can be formed using an aqueous dispersion coating solution in which a solvent-based polyvinyl chloride resin is sufficiently dispersed without using gelatin, the image density of the printed matter is improved. be able to.

  In the present invention, an aqueous dispersion coating solution containing the above-mentioned solvent-based polyvinyl chloride resin and a solvent-based release agent and substantially free of gelatin can be prepared by the following method. First, an aqueous solution and a solvent solution were prepared separately. The aqueous solution is obtained by mixing the above dispersant and water. On the other hand, the solvent-based solution is obtained by mixing the solvent-based polyvinyl chloride resin, the solvent-based release agent, and the organic solvent. If the dispersant is difficult to dissolve in water, it may be mixed in a solvent-based solution. This solvent-based solution is added to an aqueous solution and emulsified to prepare a dispersion. Then, the solvent is removed under reduced pressure while heating the dispersion at 30 to 60 ° C., the volume change of the solvent is corrected by adding pure water, and the solid content is prepared. can get. By forming the receiving layer on the heat insulation layer using the aqueous dispersion coating solution prepared in this way, the solvent-based release agent phase-separates during drying and bleeds out to the outermost surface, and the density of the release agent on the surface Can be increased. Moreover, when a receiving layer is formed by simultaneous multilayer coating, the migration of the solvent-based release agent to the lower layer can be suppressed and the surface release agent density can be increased.

  According to another preferred embodiment, it is preferable that the aqueous dispersion coating liquid for forming the receiving layer further comprises a dispersant. In addition, about a dispersing agent, it is as having demonstrated above.

  According to a preferred embodiment, the step of forming the heat insulating layer and the step of forming the receiving layer may be performed simultaneously. Furthermore, it is particularly preferable that all layers constituting the receiving layer from the heat insulating layer are formed by an aqueous coating method and a simultaneous multilayer coating method. By such a manufacturing method, effects such as improvement in interlayer adhesion of each layer of the thermal transfer image-receiving sheet and cost improvement can be obtained. When simultaneous multi-layer coating is performed in this way, a surface tension can be adjusted by adding a surfactant to the coating solution for forming each layer. Examples of the surfactant include Surfynol 440 (manufactured by Nissin Chemical Industry Co., Ltd.).

  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.

  According to a preferred aspect of the present invention, the thermal transfer image-receiving sheet production method of the present invention may further undergo a setting step and a drying step after the heat insulating layer and the receiving layer are formed by aqueous coating. 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 (dissolved solution or dispersion) is applied to one surface of a substrate sheet by, for example, a gravure printing method, a reverse roll coating method using a gravure plate, a roll coater, a bar coater, etc., and dried. Can be formed. 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 prepared by adding the above-mentioned heat-resistant resin and the above-mentioned slipperiness-imparting agent and additives that are optionally added to the solvent, and dissolving or dispersing each component to form a heat-resistant slipping layer coating solution. After the preparation, the heat-resistant slip layer coating solution can be applied on a substrate and dried.
As the solvent in the heat resistant slipping layer coating solution, the same solvents as those in the dye ink can be used.

Examples of the coating method for 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.

Example 1
1. Preparation of aqueous dispersion coating solution First, an aqueous solution 1 and a solvent solution 1 were prepared so as to have the following composition. The aqueous solution 1 and the solvent-based solution 1 are mixed and stirred, and then dispersed using a homogenizer to emulsify the solvent-based vinyl acetate resin and the solvent-based release agent in the aqueous solution. Then, an aqueous dispersion coating solution was prepared. The amount of solid content of the prepared aqueous dispersion coating liquid was 16%. This aqueous dispersion coating solution was used as a receiving layer coating solution.
Composition of aqueous solution 1-5 parts by weight of triisopropyl naphthalene sulfonic acid Na salt (dispersant, solid content 100%)-Adekapluronic F-108 (dispersant, polyoxyethylene-polyoxypropylene condensate, manufactured by ADEKA Corporation) , Solid content 100%) 5 parts by weight, 600 parts by weight of pure water
Composition of solvent-based solution 1 · Solvain C (vinyl acetate resin, manufactured by Nissin Chemical Industry Co., Ltd., solid content 100%) 100 parts by weight · X-22-3000T (solvent-based silicone release agent (epoxy-modified silicone) ), Manufactured by Shin-Etsu Chemical Co., Ltd., solid content: 100%) 5 parts by weight, ethyl acetate (solvent for dissolving silicone release agent) 600 parts by weight

2. Preparation of thermal transfer image-receiving sheet Using RC paper (manufactured by Mitsubishi Paper Industries Co., Ltd.) as a base sheet, the following heat-insulating layer coating solution and the receiving layer coating solution prepared above were heated to 40 ° C., respectively, and slide coating was performed. It was applied so that the thickness when dried was 25 μm and 5 μm, respectively. After coating, the mixture was cooled at 5 ° C. for 30 seconds and then dried at 40 ° C. for 5 minutes to obtain a thermal transfer image-receiving sheet 1 (layer constitution: base material / heat insulating layer / receiving layer). This thermal transfer image-receiving sheet had a layer structure as shown in FIG.
Composition of coating solution for heat-insulating layer · Low-pike ST (acrylic hollow particles, manufactured by Rohm and Haas Co., Ltd., volume average particle size: 0.4 µm, solid content 30%) 240 parts by weight · RR (gelatin, Nitta gelatin ( Co., Ltd., solid content 10%) 250 parts by weight ・ Hydran AP-40 (urethane resin, DIC Corporation, solid content 22%) 25 parts by weight

Example 2
A thermal transfer image-receiving sheet 2 was prepared by preparing an aqueous dispersion coating solution in the same manner as in Example 1 except that the composition of the solvent-based solution was as follows.
Composition of solvent-based solution 2 / Solvine CN (vinyl chloride-based resin, manufactured by Nissin Chemical Industry Co., Ltd., solid content 100%)
100 parts by weight. X-22-3000T (solvent silicone release agent, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by weight ethyl acetate (solvent for dissolving silicone release agent) 600 parts by weight

Example 3
An aqueous dispersion coating solution was prepared in the same manner as in Example 1 except that the composition of the solvent-based solution was as follows, and a thermal transfer image-receiving sheet 3 was prepared.
Composition of solvent-based solution 3 · Solvain CNL (vinyl chloride resin, manufactured by Nissin Chemical Industry Co., Ltd., solid content 100%)
100 parts by weight. X-22-3000T (solvent silicone release agent, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by weight ethyl acetate (solvent for dissolving silicone release agent) 600 parts by weight

Example 4
An aqueous dispersion coating solution was prepared in the same manner as in Example 1 except that the composition of the solvent-based solution was as follows, and a thermal transfer image-receiving sheet 4 was prepared.
Composition of solvent-based solution 4 · Solvain C (vinyl chloride-based resin, manufactured by Nissin Chemical Industry Co., Ltd.) 5 parts by weight · KP-1800U (solvent-based silicone release agent (epoxy-modified silicone), Shin-Etsu Chemical Co., Ltd. ), Solid content 100%) 5 parts by weight, ethyl acetate (solvent for dissolving silicone release agent) 600 parts by weight

Example 5
A thermal transfer image-receiving sheet 5 was prepared by preparing an aqueous dispersion coating solution in the same manner as in Example 1 except that the composition of the aqueous solution and the solvent-based solution was as follows.
Composition of aqueous solution 2 · 5 parts by weight of sodium dodecylbenzenesulfonate (dispersant, solid content 100%) · 5 parts by weight of Adekapluronic F-108 (polyoxyethylene-polyoxypropylene condensate, manufactured by ADEKA Corporation)・ 600 parts by weight of pure water
Composition of solvent-based solution 5 · Solvain C (vinyl chloride resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight · X-22-3000T (solvent-based silicone release agent, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by weight / ethyl acetate (solvent for dissolving silicone release agent) 600 parts by weight

Comparative Example 1
A thermal transfer image-receiving sheet 6 was prepared in the same manner as in Example 1 except that the composition of the solvent-based solution was as follows and the solvent-based solution was used as the coating solution for the receiving layer.
Composition of solvent-based solution 6 · Solvain C (vinyl acetate-based resin, manufactured by Nissin Chemical Industry Co., Ltd.) 100 parts by weight · X-22-3000T (solvent-based silicone release agent, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by weight / ethyl acetate (solvent for dissolving silicone release agent) 600 parts by weight

Comparative Example 2
The thermal transfer image-receiving sheet 7 (layer structure: substrate / material) was used in the same manner as in Comparative Example 1 except that an intermediate layer (barrier layer) coating solution having the following composition was used to provide an intermediate layer between the heat insulating layer and the receiving layer. Heat insulation layer / intermediate layer (barrier layer) / receiving layer) was prepared. The intermediate layer was applied so that the thickness when dried was 2 μm.
Composition of coating solution for intermediate layer KM-11 (polyvinyl alcohol, manufactured by Nippon Chemical Industry Co., Ltd.) 80 parts by weight Hydran AP-20 (polyurethane emulsion, manufactured by Dainippon Ink & Chemicals, Inc., solid content 30%) 100 parts by weight / solvent (water / isopropyl alcohol = 3/1) 36 parts by weight

Comparative Example 3
Except that the composition of the aqueous solution was as follows, an aqueous dispersion coating solution was prepared in the same manner as in Example 1 to prepare a thermal transfer image receiving sheet 8.
Composition of aqueous solution 3-5 parts by weight of sodium triisopropyl naphthalene sulfonate (dispersant, solid content 100%)-Adekapluronic F-108 (dispersant, polyoxyethylene-polyoxypropylene condensate, manufactured by ADEKA Corporation) , Solid content 100%) 5 parts by weight RR (gelatin, Nitta Gelatin Co., Ltd., solid content 10%) 100 parts by weight pure water 600 parts by weight

Comparative Example 4
A thermal transfer image-receiving sheet 9 was prepared in the same manner as in Example 1 except that the composition of the aqueous solution was as follows and the aqueous solution was used as the receiving layer coating solution.
Composition of aqueous solution 4 • Viniblanc 900 (vinyl chloride emulsion, manufactured by Nissin Chemical Industry Co., Ltd., solid content 40%) 250 parts by weight • KF-615A (aqueous silicone release agent (polyether-modified silicone), Shin-Etsu) Chemical Industry Co., Ltd., solid content 100%) 10 parts by weight

Evaluation of Thermal Transfer Image Receiving Sheets For the thermal transfer image receiving sheets 1 to 9 produced above, (1) evaluation of releasability, (2) evaluation of moisture and heat resistance, (3) evaluation of roughness, and (4) evaluation of image density were performed. .

(1) Evaluation of releasability Sublimation type thermal transfer printer (ALTECH ADS Co., Ltd., model: MEGAPIXELIII) which was previously heated to the thermal transfer image-receiving sheet prepared above until the head temperature reached 40 ° C. in an environment of 35 ° C. and 80%. ) Was used to print a solid black image on the produced thermal transfer image-receiving sheet, and sensory evaluation was performed to determine whether or not peeling sound could be heard.
-Evaluation standard ( circle): The peeling sound was not heard or it was a level covered with a mechanical sound.
Δ: A peeling sound was heard.
X: Printing could not be performed, and sticking between the ribbon and the image receiving paper occurred.

(2) Moisture resistance and heat bleed evaluation 18 Using the sublimation type thermal transfer printer (manufactured by ALTECH ADS, model: MEGAPICEL III), the RGB value is 15 × n (n = 0 to 17) 18 A gradation image was printed, and the print was stored in an environment of 60 ° C. Free and 40 ° C. and 90% for one week.
-Evaluation criteria ○: Not blurred.
Δ: Slightly blurred.
X: It was blurred.
(3) Roughness evaluation The thermal transfer image-receiving sheet prepared above was subjected to a sublimation-type thermal transfer printer (manufactured by ALTECH ADS, model: MEGAPICEL III), and the RGB value was 15 × n (n = 0 to 17). 18) gradation image was printed, and the sensory evaluation was visually performed to check whether the printed material had white spots or unevenness.
Evaluation criteria ○: No problem Δ: Slight white spots or unevenness occurred.
X: White spots or unevenness occurred.
(4) Image Density Evaluation A sublimation thermal transfer printer (manufactured by ALTECH ADS, model: MEGAPIXEL 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.

The results of the above evaluations are shown in Table 1. The thermal transfer image-receiving sheets of Examples 1 to 5 produced by the production method of the present invention have a releasability, moisture resistance and heat resistance, and a printed product as compared with the thermal transfer image-receiving sheets of Comparative Examples 1, 3, and 4. It can be seen that each performance of image density was improved. In addition, the thermal transfer image-receiving sheets of Examples 1 to 5 have a releasability, moisture resistance, heat resistance, and printed image, while reducing costs, as compared with Comparative Example 2 in which an intermediate layer (barrier layer) is provided. Each performance of concentration could be equal or better.

DESCRIPTION OF SYMBOLS 10 Thermal transfer image receiving sheet 11 Base material 12 Heat insulation layer 13 Receiving layer

Claims (4)

A method for producing a thermal transfer image receiving sheet, comprising a base material, and a heat insulating layer and a receiving layer in this order on the base material,
Using an aqueous coating solution containing hollow particles, forming a heat insulating layer on the substrate;
A solvent-based solution comprising a solvent-based polyvinyl chloride resin and a solvent-based release agent is added to an aqueous solution in which the gelatin content is 1% by mass or less based on the solid content mass of the polyvinyl chloride-based resin. And a step of forming a receiving layer on the heat insulating layer using an emulsified aqueous dispersion coating solution.   The method for producing a thermal transfer image receiving sheet according to claim 1, wherein the aqueous dispersion coating liquid for forming the receiving layer further comprises a dispersant.   The method for producing a thermal transfer image receiving sheet according to claim 1, wherein the solvent-based release agent is a solvent-based silicone or a fluorine-based surfactant.   The manufacturing method of the thermal transfer image receiving sheet as described in any one of Claims 1-3 which forms the said heat insulation layer and the said receiving layer by simultaneous multilayer coating.

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