JP5906903B2 - 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 and a method for producing the same, and more specifically, to a thermal transfer image receiving sheet comprising a substrate, a hollow layer, and a receiving layer on the substrate in this order, 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 general, in order to improve releasability, there are methods such as increasing the glass transition temperature (Tg) of the resin, but there is also a problem that the concentration and / or light resistance is lowered. Therefore, it has been proposed to use a thermal transfer image-receiving sheet having a receiving layer containing at least one paraffin wax dispersion and vinyl chloride latex. However, in printing in a high-temperature and high-humidity environment, the peeling sound is intense. However, depending on the composition change, there is a problem that a peeling line is generated (for example, see Patent Document 1).

  In the hard copy including the thermal transfer method, at least one paraffin wax dispersion and a vinyl chloride latex are contained in order to increase the image density of the shadow area as high as possible, and conversely to increase the image density of the highlight area. It has been proposed to use a thermal transfer image-receiving sheet having a receptive layer (see, for example, Patent Document 2). However, simply adding paraffin wax to vinyl chloride latex increases the image density in the highlight area. It was not possible to finish a soft natural image.

  Therefore, by improving the releasability at the time of printing in a high-temperature and high-humidity environment, and improving the density of the shadow part of the produced print, and reducing the highlight density, natural images in a wide range of density areas can be obtained. The development of a thermal transfer image-receiving sheet that can be realized faithfully is eagerly desired.

JP 2008-6789 A JP 2011-073340 A

  The present invention has been made in view of the above-mentioned background art, and its purpose is to improve the releasability at the time of printing in a high-temperature and high-humidity environment, to improve the density of the shadow portion of the produced printed matter, and to Another object of the present invention is to provide a thermal transfer image-receiving sheet and a method for producing the same, which can faithfully realize a natural image in a wide density range by reducing the light density.

  As a result of intensive studies to solve the above problems, the present inventors, as a result, in a thermal transfer image-receiving sheet having a specific layer structure, a binder resin, a specific wax additive, and a silicone release agent are added to the receiving layer. It discovered that the said subject could be solved by making it contain. The present invention has been completed based on such findings.

That is, according to one aspect of the present invention,
A thermal transfer image receiving sheet comprising a substrate, a hollow layer, and a receiving layer in this order on the substrate,
There is provided a thermal transfer image-receiving sheet, wherein the receiving layer comprises a binder resin, a wax additive containing polyethylene wax, and a silicone release agent.

  In the embodiment of the present invention, the polyethylene wax preferably has a melting point of 100 to 150 ° C.

  In the embodiment of the present invention, the wax additive preferably further contains an anionic emulsifier.

  In the embodiment of the present invention, it is preferable that the receiving layer further comprises a urethane-associative thickener.

  In the aspect of the present invention, the binder resin is preferably at least one selected from the group consisting of a vinyl chloride resin, a vinyl chloride acrylic resin, and a vinyl acetate resin.

  In the embodiment of the present invention, it is preferable that a primer layer is further provided between the hollow layer and the receiving layer.

  In the aspect of the present invention, it is preferable that all the layers constituting the surface side of the base material having the receiving layer are formed by aqueous coating.

According to another aspect of the invention,
A method for producing a thermal transfer image receiving sheet comprising a base material, a hollow layer, and a receiving layer in this order on the base material,
Provided is a method for producing a thermal transfer image-receiving sheet, comprising a step of forming a receptor layer using an aqueous dispersion coating liquid comprising a binder resin, a wax additive containing polyethylene wax, and a silicone release agent. The

  According to the thermal transfer image-receiving sheet of the present invention, the releasability at the time of printing in a high-temperature and high-humidity environment is improved, the density of the shadow portion of the produced printed matter is increased, and the highlight density is reduced, so that a wide range of A natural image in the density range can be faithfully realized.

1 is a schematic cross-sectional view showing an embodiment of a thermal transfer image receiving sheet according to the present invention.

Thermal transfer image-receiving sheetThe thermal transfer image-receiving sheet of the present invention comprises a substrate, a hollow layer, and a receiving layer in this order on the substrate, the receiving layer comprising a binder resin, a specific wax additive, A silicone release agent. In a preferred embodiment, the thermal transfer image-receiving sheet may further have a primer layer or an intermediate layer between the hollow layer and the receiving layer, and may further have a back layer on the surface opposite to the receiving layer. Hereinafter, the structure of the thermal transfer image receiving sheet of the present invention will be described with reference to the drawings.

  According to one aspect of the present invention, there is provided a thermal transfer image receiving sheet comprising, on a base material, two hollow layers, a primer layer, and a receiving layer in this order. Specifically, a schematic cross-sectional view of one embodiment of the thermal transfer image receiving sheet according to the present invention is shown in FIG. A thermal transfer image receiving sheet 10 shown in FIG. 1 includes a base material 11, a hollow layer A (lower layer) 12, a hollow layer B (upper layer) 13, a primer layer 14, and a receiving layer 15 on the base material 11. In this order. Hereinafter, each layer constituting the thermal transfer image receiving sheet of the present invention will be described.

Base material The base material in the present invention has a role of holding the hollow layer and the receiving layer, and heat is applied at the time of thermal transfer, so that it has mechanical strength that does not hinder handling even in a heated state. A material is preferred.

  Examples of the 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 resin-coated paper. , 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, polyether Imide, cellulose derivative, polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, acrylic, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone, Examples include polyethersulfone, 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 these synthetic resins can also 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 this invention, a commercially available base material can also be used, for example, RC paper (Mitsubishi Paper Co., Ltd. make, brand name) etc. are preferable. The base material thickness 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 base material. Specifically, the base material thickness is 50 μm. It is preferable to be within a range of ˜1000 μm, and it is more preferable to be within a 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. The receiving layer contains a binder resin, a specific wax additive, and a silicone release agent, and may further contain a urethane associative thickener. According to a preferred embodiment, the receiving layer may further contain a surfactant or the like according to various purposes.

  Binder resins contained in the receiving layer include acrylic resins, vinyl chloride resins, polyolefin resins such as polyethylene and polypropylene, polyvinyl chloride, vinyl chloride / vinyl acetate copolymers (vinyl acetate resin), poly Halogenated polymers such as vinylidene chloride, vinyl acetate / acrylic copolymers, vinyl polymers such as polyacrylates, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, ethylene and propylene, etc. And other vinyl monomers, such as copolymer resins, ionomers, cellulose resins such as cellulose diacetate, polycarbonates, and the like, and mixtures of these resins. Preferred are vinyl chloride resins such as vinyl chloride. Tree Is at least one selected from the group consisting of salt Biakuriru resins, and vinyl chloride acetate-based resin, particularly preferably a vinyl chloride acetate-based resin.

  Polyethylene wax is used as the wax additive contained in the receiving layer. Polyethylene wax includes high-density or low-density polyethylene wax, and low-density polyethylene contains many ethylene polymer branches due to its structure, whereas high-density polyethylene is relatively polyethylene. It is mainly composed of a straight chain structure. The melting point of the polyethylene wax is preferably 100 to 150 ° C, more preferably 105 to 140 ° C. If the melting point of the polyethylene wax is within the above range, the releasability at the time of printing in a high-temperature and high-humidity environment is further improved, the concentration of the shadow portion of the produced printed matter is further improved, and the highlight concentration is further reduced. be able to. The melting point is measured according to JIS K0064.

  As the polyethylene wax, polyethylene wax particles having a density of 0.94 to 0.97 (polyethylene wax finely powdered) can be suitably used. The average particle diameter of the polyethylene wax particles is preferably 20 to 170 nm, more preferably 30 to 160 nm, and still more preferably 40 to 150 nm. If the average particle size of the polyethylene wax particles is within the above range, the releasability at the time of printing in a high-temperature and high-humidity environment is further improved, the concentration of the shadow portion of the produced printed matter is further improved, and the highlight concentration is increased. It can be further reduced. The average particle diameter means a volume average particle diameter, and can be measured by a method based on JIS Z 8901, for example, a laser diffraction / scattering particle diameter / particle size distribution measuring apparatus Microtrac 3100II manufactured by Nikkiso Co., Ltd. it can.

  In the present invention, the polyethylene wax is preferably emulsified with an emulsifier, particularly an anionic emulsifier. Examples of the anionic emulsifier include alkyl carboxylates, alkyl sulfates, higher fatty acid amide sulfonates, alkyl sulfonates, alkyl benzene sulfonates, sulfosuccinates, N-acyl glutamates, alkyl ether sulfates. , Polyoxyethylene alkyl ether sulfate, phosphate, alkyl phosphate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl phenyl ether phosphate, sodium salt, potassium salt, Examples include ethanolamine salts and amino acid salts. These anionic emulsifiers may be used in combination of two or more. Since these anionic emulsifiers have polar groups, they can suppress an increase in highlight concentration and reduce dye bleeding during image storage.

  The content of the wax additive is preferably 5 to 30% by mass and more preferably 10 to 20% by mass with respect to the solid mass of the binder resin in the receiving layer. If the content of the wax additive is within the above range, the releasability at the time of printing in a high-temperature and high-humidity environment is further improved, the concentration of the shadow portion of the produced printed matter is further improved, and the highlight concentration is further increased. Can be reduced. In the present invention, commercially available polyethylene wax can also be used. For example, Hitech E-8237, Hitech E-1000, Hitech E-9015, Hitech E-6500, Hitech E-2213 (above, Toho Chemical Industry Co., Ltd.) And the like are preferable.

  Examples of the silicone release agent contained in the receiving layer include amino-modified silicone, alcohol-modified silicone, vinyl-modified silicone, urethane-modified silicone, epoxy-modified silicone, polyester-modified silicone, polyether-modified silicone, polyester-modified silicone, acrylic-modified silicone, Examples include silicone oils such as aralkyl-modified silicones and amide-modified silicones. In the present invention, these may be mixed or polymerized using various reactions. By using such a silicone 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 epoxy-modified silicone or polyether-modified silicone.

Epoxy-modified silicone used in the present invention, the viscosity is preferably 100~10000mm ² / s, more preferably 300~9000mm ² / s, more preferably 500~6000mm ² / s, even more preferably, 1000～3000Mm ² / s. The epoxy-modified silicone has an epoxy equivalent of preferably 50 to 2000, more preferably 80 to 1800, and still more preferably 100 to 1000. The viscosity can be measured by various methods of JIS Z 8803: Viscosity of liquid-Measurement method. The epoxy equivalent (g / eq) is the molecular weight value of the epoxy crosslinking agent per functional group. By using an epoxy-modified silicone having a viscosity within the above range and / or an epoxy equivalent within the above range, the releasability at the time of printing and the heat resistance / humidity resistance of the printed material can be further improved.

  The content of the silicone release agent is preferably 1 to 20% by mass, more preferably 5 to 15% by mass, based on the solid content mass of the binder resin in the receiving layer. When the content of the silicone release agent is within the above range, it is possible to further improve the releasability at the time of printing and the heat resistance and moisture resistance of the printed matter. In the present invention, a commercially available release agent may be used, and examples thereof include X22-3000T and KF410 (manufactured by Shin-Etsu Chemical Co., Ltd.). Use of such an epoxy-modified silicone is preferable from the viewpoint of combination with the binder resin.

The urethane associative thickener contained in the receiving layer has a viscosity when measured at a liquid temperature of 25 ° C. according to JIS Z8803 using a B-type viscometer when the solid concentration is 30%. , Preferably it is 1000-100000 mPa * s, More preferably, it is 2000-60000 mPa * s. Furthermore, the viscosity ratio is the following formula (1):
Viscosity ratio = V _30,6 / V _30,60 (1)
_{(Wherein, V 30,6} by using a B-type viscometer, in conformity with JIS Z8803, a viscosity (mPa.s) when the rotational speed 6rpm at a liquid temperature 25 ° _{C., V 30, 60} is B Using a viscometer, the viscosity (mPa.s) at a liquid temperature of 25 ° C. and a rotational speed of 60 rpm is shown in accordance with JIS Z8803)
And is preferably 2.0 to 5.0, more preferably 2.0 to 4.5. This viscosity ratio is generally called a thixotropy index (TI) and is an index that correlates with sagging difficulty. By using a urethane associative thickener with a viscosity and a viscosity ratio in the above range, it gives leveling viscosity to the coating solution for the receiving layer, improves surface quality, and exists in the form of particles. Binders are bound together to form a film, and heat fusion during image printing can be suppressed.

  The content of the urethane associative thickener is preferably 1 to 10% by mass, more preferably 2 to 5% by mass, based on the solid content of the binder resin in the receptor layer. When the content of the urethane associative thickener is within the above range, the receptor layer can be sufficiently formed, and heat fusion during image printing can be suppressed. In the present invention, a commercially available urethane associative thickener can also be used. For example, UH-450, UH-526, UH-530, UH-540, UH-550 (above, manufactured by ADEKA Corporation), SN thickener A812 (manufactured by San Nopco) is preferable.

Hollow layer The hollow layer in the present invention has a heat insulating property that can prevent heat applied during image formation by thermal transfer from being lost due to heat transfer to a substrate or the like. In a preferred embodiment, the hollow layer contains hollow particles and may further contain a hydrophilic binder and other additives. According to a preferred embodiment, the hollow layer may be composed of two or more layers. A hollow layer is provided with cushioning properties by including hollow particles. Here, the degree of cushioning property of the hollow layer can be appropriately adjusted according to the application of the thermal transfer image receiving sheet. The degree of cushioning property of the hollow layer can also be adjusted to an arbitrary range by changing the thickness of the hollow layer, for example. The thickness of the hollow layer is not particularly limited as long as the heat insulating property, cushioning property and the like can be adjusted to a desired level, but preferably in the range of 10 μm to 100 μm, and in the range of 10 μm to 50 μm. More preferably, it is within. The density of the hollow 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} .

  The average particle diameter 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 average particle diameter of the hollow particles is in the above range, heat insulation and cushioning properties can be imparted to the hollow layer. This is because if the average particle size is too small, the amount of hollow particles used increases and the cost increases, and if the average particle size is too large, it becomes difficult to form a smooth hollow 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 insulation and cushioning properties can be imparted to the hollow 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, Ropeke HP-1055, Ropeke HP-91, Ropeke OP-84J, Ropeke Ultra and Ropeke SE (manufactured by Rohm and Haas Co., Ltd.), Nipol MH-5055 (Nippon Zeon Corporation), SX8782 and SX866 (JSR Corporation) are preferred.

Other Layers The thermal transfer image receiving sheet of the present invention may further have other layers other than the above layers. In a preferred embodiment, the thermal transfer image-receiving sheet can further have other layers such as a primer layer and an intermediate layer on the receiving layer side. Moreover, it can have a back surface layer on the opposite side to a receiving layer.

Primer layer The primer layer in the present invention has a role of satisfactorily adhering the hollow layer and the receiving layer, and prevents image migration to the hollow layer side in a high-temperature and high-humidity environment, thereby improving image storage stability. It has a function. In a preferred embodiment, the primer layer contains hollow particles, a resin, and a hydrophilic binder, and the 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.

  According to a preferred embodiment of the present invention, the hydrophilic binder contained in the hollow layer or primer layer described above includes gelatin and derivatives thereof, polyvinyl alcohol, polyethylene oxyside, polyvinyl pyrrolidone, pullulan, carboxymethyl cellulose, hydroxyethyl cellulose, Examples include dextran, dextrin, polyacrylic acid and salts thereof, agar, κ-carrageenan, λ-carrageenan, ι-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 of each layer 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. For example, RR, R, CLV, G1236 (manufactured by Nitta Gelatin Co., Ltd.) and the like are preferable.

Intermediate Layer In the present invention, at least one intermediate layer may be provided between the hollow layer and the primer layer or between the primer layer and the receiving layer. By providing an intermediate layer, functions such as solvent resistance, dye diffusion barrier during image storage under high temperature / high humidity, interlayer adhesion, white color imparting, glare / unevenness of the substrate, and antistatic functions are added. Can do. As a method for forming the intermediate layer, known means can be used. For example, an optical brightener, inorganic fine particles, hollow fine particles, and an organic conductive material such as a conductive filler or polyaniline sulfonic acid are added to the intermediate layer. The method of doing is mentioned.

Back layer The back layer in the present invention has the fixability of ink used in an ink jet method, a dot impact method, a writing instrument, and the like, and enables a back print excellent in quick-drying with less bleeding of the recording portion ( To improve the backprint suitability). Furthermore, it also has the basic characteristics as the image receiving paper back side described below.
1. When superposed on the receiving layer surface, no sticking (blocking) occurs even if it is stored under a temperature or load.
2. Even when the paper is mistakenly mounted on the printer with the front and back sides reversed, and the thermal transfer sheet is superposed on the thermal transfer sheet, it will stick to the thermal transfer sheet and will not clog in the printer, and the printed matter will be discharged. (Has back surface releasability).
3. Even if it rubs against the receiving layer surface, the receiving layer surface is not damaged, and the particle component does not fall off (powder off) from the back layer.
The back layer preferably contains a binder resin and inorganic fine particles, and other additives such as an antifoaming agent and an antistatic agent can be appropriately added to the back layer. In recent years, a water-based coating method is preferred from the viewpoint of environmental considerations, but the back layer of the present invention can be particularly suitably used as the back surface of an image receiving paper on which a receiving layer is formed by a water-based coating method.

  The binder resin contained in the back layer is preferably at least one selected from the group consisting of styrene / acrylic resins, polyester resins, polyurethane resins, and acrylic resins. By using such a binder resin, it is possible to have good adhesion to the base material and good backprint suitability. In the present invention, a commercially available binder resin can also be used, such as Bironal MD 1500 (manufactured by Toyobo Co., Ltd.), Plus Coat Z690 (manufactured by Kyoyo Chemical Co., Ltd.), Superflex 130 (Daiichi Kogyo Seiyaku ( Etc.) are preferable.

  The inorganic fine particles contained in the back layer are at least one selected from the group consisting of colloidal alumina, colloidal silica, and silica particles. By using such inorganic fine particles, it is possible to improve the backprint suitability and prevent blocking.

In the present invention, but are not coating amount of the back layer is particularly limited, it is preferable that the coating amount is in the range of drying after ^{0.1g / m 2 ~3.0g / m 2} , 0.3g / More preferably, it is in the range of m ^{2 to} 1.5 g / m ² . If the coating amount is in the above range, sufficient back print suitability can be obtained.

Method for Producing Thermal Transfer Image-Receiving Sheet The method for producing a thermal transfer image-receiving sheet of the present invention is a method for producing a thermal transfer image-receiving sheet comprising a substrate, a hollow layer, and a receptor layer in this order on the substrate. And a step of forming a receptor layer using an aqueous dispersion coating liquid containing a binder resin, a wax additive containing polyethylene wax, and a silicone release agent. In the present invention, it is preferable that all layers constituting the surface side having the receiving layer are formed by aqueous coating, preferably by aqueous coating and simultaneous multilayer coating. For the application of each layer of the thermal transfer image-receiving sheet, known methods such as roll coating, bar coating, gravure coating, gravure reverse coating, die coating, slide coating, and curtain coating can be used. A method in which a plurality of layers such as a slide coat and a curtain coat can be applied simultaneously in multiple layers is preferred. 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.

Aqueous dispersion coating liquid The aqueous dispersion coating liquid used for forming the receiving layer in the present invention can be obtained by dispersing (emulsifying) a binder resin, a wax additive, and a silicone release agent in water by a known method. it can. For example, the aqueous dispersion coating liquid can be prepared by mixing a wax additive in the state of an aqueous dispersion and another aqueous dispersion. First, an aqueous dispersion and a solvent-based solution are prepared separately. The aqueous solution is obtained by mixing the above emulsifier and water. On the other hand, the solvent-based solution is obtained by mixing the above polyethylene wax and a known organic solvent (solvent). The aqueous solution and the solvent solution are mixed and stirred, and then dispersed using a homogenizer to prepare a dispersion. Thereafter, the solvent is removed under reduced pressure while heating the dispersion to 30 to 60 ° C., the volume change of the solvent is corrected by adding pure water, and the solid content is prepared to obtain an aqueous dispersion. It is done.

  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. The organic solvent used for the preparation of the solvent-based solution is not particularly limited as long as it can dissolve the dye. Ethyl acetate, aromatic hydrocarbon solvents such as toluene and benzene, ketone solvents such as acetone and methyl ethyl ketone, and mixtures thereof Those selected from the group consisting of: 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.

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) 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 mass, preferably 5 to 70% by mass. 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, 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 slipping 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 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 more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples. In addition, the mass part of description described was described by solid content, and it diluted with the pure water as needed.

Example 1
Using RC paper (manufactured by Mitsubishi Paper Industries Co., Ltd.) as a base material for producing the thermal transfer image-receiving sheet 1, the coating liquid 1 for the hollow layer A, the coating liquid 1 for the hollow layer B, the coating liquid 1 for the primer layer, and the receptor having the following composition the layers coating liquid 1 was heated respectively to 40 ° C., using a slide coating, the coating amount after drying respectively ^{2.0g / m 2, 3.0g / m} 2, 3.0g / m 2, 3.0g / M ² is applied simultaneously, and is cooled at 5 ° C. for 30 seconds, and then dried at 50 ° C. for 2 minutes. The thermal transfer image-receiving sheet 1 (layer structure: back layer / base material / hollow layer A / hollow Layer B / Primer layer / Receptive layer) was obtained. The coating speed was 20 m / min. This thermal transfer image-receiving sheet had a layer structure as shown in FIG.
Composition of hollow layer A coating solution 1 (for lower layer) Hollow particles (volume average particle size: 0.5 μm, average hollow ratio: 45%, manufactured by Rohm and Haas Co., Ltd., trade name: Ropeke ST) 55 parts by mass Gelatin (made by Nitta Gelatin Co., Ltd., trade name: G1236) 26 parts by mass Binder resin (styrene / acrylic resin, made by Shin Nakamura Chemical Co., Ltd., trade name: New Coat B-13) 8 parts by mass Binder resin (styrene / acrylic resin, manufactured by BASF Japan Ltd., trade name: Jonkrill 62J) 8 parts by mass
Composition of hollow layer B coating solution 1 (for upper layer) Hollow particles (volume average particle size: 0.5 μm, average hollow ratio: 45%, manufactured by Rohm and Haas Co., Ltd., trade name: Ropeke ST) 59 parts by mass Gelatin (Nitta Gelatin Co., Ltd., trade name: G1236) 28 parts by mass Binder resin (Styrene / acrylic resin, Shin Nakamura Chemical Co., Ltd., trade name: New Coat B-13) 5 parts by mass Binder resin (styrene / acrylic resin, manufactured by BASF Japan Ltd., trade name: Jonkrill 62J) 8 parts by mass
Composition of coating liquid 1 for primer layer : Hollow particles (crosslinked hollow particles, volume average particle size: 0.4 μm, average hollow ratio: 39%, manufactured by Rohm and Haas Co., Ltd., trade name: OA-39) 70 parts by mass・ Gelatin (made by Nitta Gelatin Co., Ltd., trade name: G1236) 16 parts by mass ・ Fluorescent whitening agent (made by Showa Chemical Industry Co., Ltd., trade name: WN-1) 4 parts by mass ・ Binder resin (styrene / acrylic Resin, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: New Coat B-13) 2 parts by mass Binder resin (styrene / acrylic resin, manufactured by BASF Japan Ltd., trade name: John Krill 62J) 2 parts by mass
Composition of coating solution 1 for receiving layer 100 parts by mass of binder resin 1 Urethane associative thickener (viscosity: 2000, viscosity ratio: 3.0ADEKA, trade name: UH-526) 3.8 parts by mass Wax additive 1 (polyethylene wax (Hitech E-8237 (manufactured by Toho Chemical Industry Co., Ltd., melting point 106 ° C., average particle size 80 nm) 12 parts by mass) release agent (silicone dispersion 1) 10 parts by mass Agent (manufactured by Nagase ChemteX Corp., trade name: Denacol EX512)
5 parts by mass-surfactant (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.5 parts by mass of the receiving layer coating solution is an aqueous dispersion coating solution in which the above components are dispersed in water by a known method. It is.

Preparation of binder resin 1 The binder resin 1 used in the coating solution 1 for the receiving layer was prepared as follows. In a 2.5 L autoclave, 600 g of deionized water, 438.8 g of vinyl chloride monomer (97.5% by mass with respect to all charged monomers), and 2.25 g of potassium persulfate were charged. The reaction mixture was stirred with a stirring blade so as to maintain a rotation speed of 120 rpm, and the temperature of the reaction mixture was raised to 60 ° C. to initiate polymerization. 11.2 g of glycidyl methacrylate (2.5% by mass based on all charged monomers) was continuously added at a rate of 2.8 g / hr from the start of polymerization to 4 hours later, and the vinyl chloride monomer at a polymerization pressure of 60 ° C. The polymerization was stopped when the saturated vapor pressure decreased by 0.6 MPa to obtain a vinyl chloride resin latex.

Preparation of Silicone Dispersion 1 Silicone Dispersion 1 used in Receptive Layer Coating Solution 1 was dispersed as follows to prepare an aqueous dispersion. First, an aqueous solution 1 and a solvent-based solution 1 were prepared so as to have the following composition. The aqueous solution 1 and the solvent solution 1 were mixed and stirred, and then dispersed using a homogenizer to prepare a dispersion. Thereafter, the dispersion was desolvated under reduced pressure while being heated to 30 to 60 ° C., the volume change of the desolvated part was corrected by adding pure water, and the solid content was adjusted to 17%. An aqueous dispersion was obtained.
Composition of aqueous solution 1 · Triisopropyl naphthalene sulfonic acid Na salt (dispersant, solid content 10%) 10 parts by mass · Pure water 56 parts by mass
Composition of solvent-based solution 1 Silicone (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: X-22-3000T) 11 parts by mass Silicone (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-410) 6 parts by weight・ 17 parts by mass of ethyl acetate

Example 2
Preparation of thermal transfer image-receiving sheet 2 A thermal transfer image-receiving sheet 2 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 2 for receiving layer 100 parts by weight of binder resin 1 Urethane associative thickener (trade name: UH-526, manufactured by ADEKA Corporation) 3.8 parts by weight of wax additive 2 (polyethylene wax ( Hitec E-1000 (manufactured by Toho Chemical Industry Co., Ltd., melting point 137 ° C., average particle size 140 nm)) 12 parts by mass / release agent (silicone dispersion 1) 10 parts by mass / epoxy crosslinking agent (Nagase ChemteX Corporation) (Product name: Denacol EX512)
5 parts by mass / surfactant (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.5 parts by mass

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 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of Receptive Layer Coating Solution 3 Binder Resin 1 100 parts by mass Urethane Associative Thickener (trade name: UH-526, manufactured by ADEKA Corporation) 3.8 parts by mass Wax Additive 3 (polyethylene wax ( Hitec E-9015 (manufactured by Toho Chemical Industry Co., Ltd., melting point 137 ° C., average particle size 50 nm)) 12 parts by mass, release agent (silicone dispersion 1) 10 parts by mass, epoxy crosslinking agent (Nagase ChemteX Corporation) (Product name: Denacol EX512)
5 parts by mass / surfactant (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.5 parts by mass
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 Receptive Layer Coating Solution 4 Binder Resin 1 100 parts by mass Urethane Associative Thickener (ADEKA Corporation, trade name: UH-526) 3.8 parts by mass Wax Additive 4 (polyethylene wax ( Hitec E-6500 (manufactured by Toho Chemical Industry Co., Ltd., melting point 140 ° C., average particle size 50 nm)) 12 parts by mass / release agent (silicone dispersion 1) 10 parts by mass / epoxy crosslinking agent (Nagase ChemteX Corporation) (Product name: Denacol EX512)
5 parts by mass / surfactant (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.5 parts by mass

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 100 parts by weight of binder resin 1 Urethane associative thickener (trade name: UH-526, manufactured by ADEKA Corporation) 3.8 parts by weight of wax additive 5 (polyethylene wax ( Hitec E-2213 (manufactured by Toho Chemical Industry Co., Ltd., melting point 140 ° C., average particle diameter 60 nm)) 12 parts by mass, release agent (silicone dispersion 1) 10 parts by mass, epoxy crosslinking agent (Nagase ChemteX Corporation) (Product name: Denacol EX512)
5 parts by mass / surfactant (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.5 parts by mass

Comparative Example 1
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 liquid 6 for receiving layer 100 parts by mass of binder resin 1 Urethane associative thickener (made by ADEKA, trade name: UH-526) 3.8 parts by mass of release agent (silicone dispersion 1 ) 10 parts by mass / Epoxy crosslinking agent (manufactured by Nagase ChemteX Corp., trade name: Denacol EX512)
5 parts by mass / surfactant (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.5 parts by mass

Comparative Example 2
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 100 parts by weight of binder resin 1 Urethane associative thickener (trade name: UH-526, manufactured by ADEKA Corporation) 3.8 parts by weight of wax additive 6 (aqueous dispersion) Carnauba wax (manufactured by Chukyo Yushi Co., Ltd., trade name: Cellosol 524) 12 parts by mass, release agent (silicone dispersion 1) 10 parts by mass, epoxy crosslinking agent (manufactured by Nagase ChemteX Corporation, trade name) : Denacol EX512)
5 parts by mass / surfactant (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.5 parts by mass

Comparative Example 3
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 liquid 8 for receiving layer 100 parts by weight of binder resin 1 Urethane associative thickener (trade name: UH-526, manufactured by ADEKA Corporation) 3.8 parts by weight Wax additive 7 12 parts by weight Release agent (Silicone dispersion 1) 10 parts by mass / Epoxy crosslinking agent (manufactured by Nagase ChemteX Corporation, trade name: Denacol EX512)
5 parts by mass / surfactant (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.5 parts by mass

Wax additive 7
The wax additive 7 used in the receiving layer coating solution 8 was dispersed as follows to prepare an aqueous dispersion. First, the aqueous solution 2 was prepared so that it might become the following composition. This aqueous solution 2 (66 parts by mass) and a wax melted by heating (paraffin wax (Paraffin Wax-155, manufactured by Nippon Seiki Co., Ltd., melting point 69 ° C.) (17 parts by mass)) are mixed and stirred. After that, dispersion was performed using a homogenizer to prepare a dispersion. Thereafter, while the dispersion was heated to 30 to 60 ° C., the solid content was adjusted to 17%, and an aqueous dispersion of wax additive 7 was obtained.
Composition of aqueous solution 2 -Triisopropyl naphthalene sulfonic acid Na salt (dispersant, solid content 10%) 10 parts by mass-Pure water 56 parts by mass

Comparative Example 4
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 Receptor Layer Coating Solution 9 Binder Resin 1 100 parts by weight Thickener (ADEKA Corporation, trade name: UH-526) 3.8 parts by weight Wax Additive 1 12 parts by weight Epoxy crosslinking agent (Nagase ChemteX Co., Ltd., trade name: Denacol EX512)
5 parts by mass / surfactant (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.5 parts by mass

Evaluation of Thermal Transfer Image Receiving Sheet The thermal transfer image receiving sheets 1 to 9 produced above were subjected to (1) image density evaluation, (2) releasability evaluation, (3) image storage stability evaluation, and (4) sticking resistance evaluation. .

(1) Image Density Evaluation A sublimation thermal transfer printer (manufactured by ALTECH ADS, model: MEGAPIXELIII) 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 (max). Further, to evaluate the highlight property from the difference (.DELTA.OD _2-1) with OD values (OD ₂₎ of the OD value of the low density portion Gray _{(n = 0) (OD 1} ) and the second step (n = 1) (HL).
・Evaluation criteria (max)
5: OD value was 1.95 or more 4: OD value was 1.90 or more and less than 1.95 3: OD value was 1.85 or more and less than 1.90 2: OD value was 1 .80 or more and less than 1.85 1: OD value was less than 1.80 ・Evaluation criteria (HL)
3: .DELTA.OD _2-1 was less than 0.02.
2: .DELTA.OD _2-1 is less than 0.02 or more 0.03.
1: ΔOD _2-1 was 0.03 or more.

(2) Evaluation of releasability Sublimation type thermal transfer printer (manufactured by ALTECH ADS, model: MEGAIXEL III) and ink ribbon (for Megapixel III, genuine product of Altec AD Co., Ltd.) Was used to print a solid black image, and the peeling sound generated at that time was subjected to sensory evaluation. Similarly, after leaving for 3 hours in a high-temperature and high-humidity environment at 40 ° C. and 85% RH), a solid black image was printed in that environment, and the peeling sound generated at that time was subjected to sensory evaluation.
Evaluation criteria 5: No peeling sound was heard.
4: A slight peeling sound was heard at the time of printing the third color, but there was no practical problem.
3: A large peeling sound was heard at the time of printing the third color, and there was a problem in practical use.
2: A peeling sound was heard at the time of printing the 2nd color.
1: Could not print.

(3) Evaluation of image storability A 0.5 mm-wide linear image (black) is printed on the thermal transfer image-receiving sheet produced above using a sublimation type thermal transfer printer (manufactured by ALTECH ADS, model: MEGAPICEL III), and the printed matter. Was stored for one week in a 60 ° C. Free environment and a 40 ° C. 90% RH environment, and the image blur was visually sensory 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.

(4) Evaluation of sticking resistance The sublimation type thermal transfer printer (manufactured by ALTECH ADS, model: MEGAPICEL III) and ink ribbon (for Megapixel III, Altech AD Co., Ltd. genuine product) are applied to the thermal transfer image receiving sheet prepared above. After leaving it for 3 hours in a high-temperature and high-humidity environment (35 ° C. and 80% RH) without condensation, a black solid image was printed in that environment, and the streaky unevenness (sticking) generated at that time was visually evaluated. .
Evaluation criteria 5: No sticking was observed between the thermal transfer image receiving sheet and the thermal transfer ink sheet.
4: Almost no sticking was observed between the thermal transfer image receiving sheet and the thermal transfer ink sheet.
3: While the thermal transfer ink sheet was moved, some sticking was observed on the surface of the thermal transfer image receiving sheet, but no wrinkles were observed on the thermal transfer ink sheet.
2: When the thermal transfer ink sheet was moved, some sticking was observed on the surface of the thermal transfer image receiving sheet, and some wrinkles were observed on the thermal transfer ink sheet.
1: When the thermal transfer ink sheet was moved, obvious sticking was observed on the surface of the thermal transfer image receiving sheet, and strong wrinkles were observed on the thermal transfer ink sheet.

The results of the above evaluations are shown in Table 1. Each evaluation result shows that it is so favorable that a numerical value is large. The thermal transfer image-receiving sheet of the example satisfying the composition of the present invention improves the releasability at the time of printing in a high-temperature and high-humidity environment as compared with the thermal transfer image-receiving sheet of the comparative example, and the density of the shadow portion of the produced printed matter is increased. It can be seen that a natural image in a wide density range can be faithfully realized by improving and reducing the highlight density.

10 Thermal transfer image-receiving sheet 11 Base material 12 Hollow layer A (lower layer)
13 Hollow layer B (upper layer)
14 Primer layer 15 Receptor layer

Claims (8)

A thermal transfer image receiving sheet comprising a base material, a hollow layer, and a receiving layer in this order on the base material,
The receptor layer comprises a binder resin, a wax additive including polyethylene wax particles, and a silicone release agent;
A thermal transfer image-receiving sheet, wherein the polyethylene wax particles have an average particle size of 20 to 170 nm. The thermal transfer image-receiving sheet according to claim 1, wherein the polyethylene wax particles have a melting point of 100 to 150 ° C.   The thermal transfer image-receiving sheet according to claim 1 or 2, wherein the wax additive further comprises an anionic emulsifier.   The thermal transfer image-receiving sheet according to any one of claims 1 to 3, wherein the receptor layer further comprises a urethane-associative thickener.   The binder resin contained in the receiving layer is at least one selected from the group consisting of a vinyl chloride resin, a vinyl chloride acrylic resin, and a vinyl acetate resin, according to any one of claims 1 to 4. The thermal transfer image receiving sheet described.   The thermal transfer image receiving sheet according to any one of claims 1 to 5, further comprising a primer layer between the hollow layer and the receiving layer. The thermal transfer image receiving sheet according to any one of claims 1 to 6, wherein all the layers constituting the surface side having the receiving layer of the substrate are aqueous coating layers . A method for producing a thermal transfer image receiving sheet comprising a base material, a hollow layer, and a receiving layer in this order on the base material,
Using a water-based dispersion coating liquid containing a binder resin, a wax additive containing polyethylene wax particles, and a silicone release agent, and forming a receiving layer.
The manufacturing method of the thermal transfer image receiving sheet whose average particle diameter of the said polyethylene wax particle is 20-170 nm.

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