JP2013075470A - Thermal transfer image receiving sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer image receiving sheet having each kind of performance such as image density, image storability, and mold releasability.SOLUTION: The thermal transfer image receiving sheet sequentially includes a substrate, at least three intermediate layers on the substrate, and a receiving layer. The lowermost layer of the at least three intermediate layers includes a hollow particle, an acrylic resin, and a toning agent. Using the thermal transfer image receiving sheet satisfying the composition can improve each kind of performance such as image density, image storability, and mold releasability.

Description

  The present invention relates to a thermal transfer image receiving sheet, and more particularly to a thermal transfer image receiving sheet comprising a base material, and at least three hollow layers on the base material, and a receiving layer in this order.

  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, in order to adjust the whiteness and hue of the image receiving sheet, a method for toning the base paper has been studied, but there has been a problem that unevenness occurs on the coated surface. Therefore, it has been studied to provide an intermediate layer (toning layer) between the base material of the image receiving sheet and the receiving layer. For example, it has been proposed to form an intermediate layer using an organic solvent-based coating liquid containing a white pigment and other pigments and additives (see, for example, Patent Documents 1 and 2). However, in recent years, from the viewpoint of environmental considerations and safety, it is desired to form each layer of the image receiving sheet using an aqueous coating solution.

  Therefore, it is anxious to develop a thermal transfer image-receiving sheet that can achieve desired chromaticity and is excellent in performance such as surface quality by a manufacturing method using an aqueous coating solution.

JP-A-6-115260 Japanese Patent Laid-Open No. 10-244767

  As a result of examining the above background art, the present inventors newly performed simultaneous multilayer coating using an aqueous coating solution in order to form an intermediate layer (toning layer) or a receiving layer of a thermal transfer image receiving sheet. The present inventors have found that the color material contained in the intermediate layer coating solution diffuses to other layers, resulting in a decrease in toning accuracy. Further, the inventors have also found that the diffusion of the color material to other layers reduces the light resistance of the image receiving sheet and causes the image receiving sheet to turn yellow. The present invention has been made in view of the above-mentioned background art and these newly discovered problems, and the object thereof is to achieve a desired chromaticity, and thermal transfer excellent in each performance such as surface quality and image storage stability. It is to provide an image receiving sheet.

  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, at least three layers of hollow layers in the lowermost layer, a resin having hollow particles and an acrylic acid moiety; It discovered that the said subject could be solved by containing a coloring agent. 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 base material, at least three hollow layers on the base material, and a receiving layer in this order,
There is provided a thermal transfer image-receiving sheet in which the lowermost layer of the at least three hollow layers comprises a hollow particle, a resin having an acrylic acid site, and a colorant.

  In the aspect of the present invention, it is preferable that all of the at least three hollow layers further contain gelatin.

  In the aspect of the present invention, it is preferable that the receiving layer comprises a binder resin, a wax additive, and a urethane-associative thickener.

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

  According to the thermal transfer image receiving sheet of the present invention, various performances such as image density, image storability, and releasability can be improved.

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 sheet The thermal transfer image-receiving sheet of the present invention comprises a base material, on the base material, at least three hollow layers, and a receiving layer in this order, and the lowest layer of at least three hollow layers, Hollow particles, an acrylic resin, and a coloring agent are included. In a preferred embodiment, a back layer may be further provided 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 one surface of a substrate, three 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 (middle layer) 13, and a hollow layer C (upper layer) on one surface of the base material 11. 14 and the receiving layer 15 in this order. Hereinafter, each layer constituting the thermal transfer image receiving sheet of the present invention will be described.

Substrate In the present invention, the substrate has a role of holding at least three hollow layers and a receiving layer, and heat is applied at the time of thermal transfer, so that there is no trouble in handling even in a heated state. It is preferable that the material has a sufficient strength.

  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.

Hollow layer The hollow layer in the present invention has a hollow property capable of preventing heat applied during image formation by thermal transfer from being lost due to heat transfer to a substrate or the like. In the present invention, the hollow layer is composed of at least three layers. The lowermost layer of the hollow layer includes hollow particles, a resin having an acrylic acid site, and a coloring agent. The uppermost layer of the hollow layer preferably comprises a natural rubber latex / methyl methacrylate graft polymerization emulsion. By providing three or more hollow layers with such a configuration, the lowermost layer can be provided with a color control function, and the uppermost layer can be provided with a crack suppressing function for the formed film.

  The colorant may be any colorant as long as it can provide an appropriate color tone, and examples thereof include DISPERSE RED 60, DISPERSE VIOLET 26, DISPERSE BLUE 354, and the like. By adding such a colorant to the lowermost layer of the hollow layer, the ground color can be adjusted without any trouble even when the ground color of the paper varies.

  Since the colorant is non-hydrophilic, it is preferably blended in the hollow layer coating liquid as an aqueous dispersion. For example, the aqueous dispersion can be prepared by the following method. First, an aqueous solution and a solvent solution are prepared separately. 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 aqueous solution is obtained by mixing a dispersant and water. Gelatin may be further added to the aqueous solution. On the other hand, the solvent-based solution is obtained by mixing a colorant and an 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. 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 resin having an acrylic acid moiety includes a polymer of an acrylic acid or methacrylic acid monomer or a derivative thereof, a copolymer of an acrylic acid or methacrylic acid monomer and another monomer, or a derivative thereof. 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. Two or more kinds of acrylic resins may be mixed and used.

  The above-mentioned natural rubber latex / methyl methacrylate graft polymerization emulsion is obtained by adding 50 to 80 mass%, preferably 55 to 75 mass% of methyl methacrylate to the natural rubber latex. Natural rubber latex has strong adhesiveness and low emulsion stability, making it difficult to maintain a stable coating solution state. Therefore, by adding methyl methacrylate, the tackiness is reduced, workability is improved, and the coating solution is also stabilized. Further, since methyl methacrylate is added, the dispersibility of the disperse dye is low, and the flexibility of the film can be maintained without deteriorating the bleeding property as compared with other latex materials. By adjusting the addition rate of methyl methacrylate within the above range, the properties of natural rubber latex are expressed and the uniformity of the coating solution is prevented from being deteriorated, and the detergency of the dried film is reduced and suitability in the process. Can be prevented from decreasing. Furthermore, cracks can be suppressed by maintaining the flexibility of the formed film.

  The addition of methyl methacrylate to the natural rubber latex can be performed by a conventionally known method. For example, when carrying out graft copolymerization of natural rubber latex with methyl methacrylate, an emulsifier is added to the natural rubber latex, and after nitrogen substitution, methyl methacrylate is added with stirring, and further, the graft polymerization treatment is performed while adding an initiator dropwise. It can be performed. As the emulsifier, an amine surfactant or a reactive surfactant is used. The initiator for graft polymerization is not particularly limited, and examples thereof include redox initiators such as combinations of peroxides such as benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide and amines. The addition amount of the polymerization initiator is preferably about 0.001 to 2% by mass with respect to methyl methacrylate. The polymerization treatment is desirably performed at 10 to 70 ° C. for 2 to 100 hours under nitrogen substitution.

In the present invention, the hollow layer includes hollow particles, thereby providing cushioning properties. 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 hollowness, cushioning properties and the like can be adjusted to a desired level, but are 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.

  In a preferred embodiment, all the layers of the hollow layer further contain gelatin and may further contain other additives. 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.

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 preferably comprises a binder resin, a wax additive, and a urethane associative thickener. According to a preferred embodiment, the receiving layer may contain a release agent, 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 polymers such as polyvinyl acetate and polyacrylates, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, olefins such as ethylene and propylene, and other Examples thereof include copolymer resins with vinyl monomers, ionomers, cellulose resins such as cellulose diacetate, and polycarbonates. In particular, it is preferable to use at least one selected from the group consisting of a vinyl chloride resin, a polyester resin, and an acrylic resin.

  Examples of the wax additive contained in the receiving layer include carnauba wax and paraffin wax, and these may be used alone or in combination. In the present invention, the carnauba wax includes natural carnauba wax and purified products and derivatives thereof, including those modified with additives and the like. According to a preferred embodiment, the melting point of carnauba wax is 80 to 90 ° C., the acid value is 10 mg · KOH / g or less, and the saponification value is 78 to 88 mg · KOH / g. The paraffin wax includes natural paraffin wax and purified products and derivatives thereof, and those modified with additives and the like. The melting point of the paraffin wax is preferably 40 to 105 ° C, more preferably 40 to 90 ° C, and further preferably 40 to 75 ° C.

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 5 to 20% by mass, more preferably 6 to 15% 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.

  Examples of the release agent contained in the receiving layer include silicone oil (including reaction-curable silicone), phosphate ester plasticizers, and fluorine compounds, and silicone oil is particularly preferable. Various silicones such as dimethyl silicone can be used as the silicone oil. Specifically, amino-modified silicone, epoxy-modified silicone, alcohol-modified silicone, vinyl-modified silicone, urethane-modified silicone, polyester-modified silicone, polyether-modified silicone, polyester-modified silicone oil, acrylic-modified silicone, amide-modified silicone, etc. These may be mixed or polymerized using various reactions. Two or more release agents may be mixed and used. By using such a release agent, problems such as fusion between the thermal transfer ink sheet and the receiving layer of the thermal transfer image receiving sheet and a decrease in printing sensitivity during printing can be improved. In the present invention, it is particularly preferable to use a polyether-modified silicone type release agent. Two or more polyether-modified silicone mold release agents may be used, or other mold release agents may be used in combination. 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.

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, an intermediate layer, and a release 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 primer layer or the like includes gelatin and its derivatives, polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, pullulan, carboxymethyl cellulose, hydroxyethyl cellulose, dextran, dextrin. And 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.

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

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 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.

Manufacturing Method of Thermal Transfer Image Receiving Sheet A known manufacturing method can be used for manufacturing the thermal transfer image receiving sheet of the present invention. For applying 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. In the present invention, on the surface side having the receiving layer, it is preferable to form all the layers constituting the receiving layer from the hollow layer by aqueous coating.

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, 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
Preparation of thermal transfer image-receiving sheet 1 RC paper (manufactured by Mitsubishi Paper Industries Co., Ltd.) is used as a base sheet, coating solution 1 for hollow layer A (lower layer), coating solution 1 for hollow layer B (middle layer), hollow layer having the following composition The coating solution 1 for C (upper layer) and the coating solution 1 for the receiving layer were heated to 40 ° C., respectively, and applied using a slide coating so that the thickness when dried was 3 μm, 3 μm, 4 μm, and 3 μm, After cooling at 5 ° C. for 30 seconds, it was dried at 40 ° C. for 2 minutes to obtain a thermal transfer image-receiving sheet 1 (layer constitution: substrate / hollow layer / receiving layer).
Composition of coating solution 1 for hollow layer A (lower layer) Hollow particles (volume average particle size: 0.4 μm, average hollowness: 45%, manufactured by Rohm and Haas Co., Ltd., trade name: Ropeke ST) 55 parts by mass Colorant dispersion 1 5 parts by mass Binder resin (acrylic resin, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: Newcoat KT-1030) 10 parts by mass Binder resin (styrene / acrylic / acrylic acid resin, BASF Japan Co., Ltd., trade name: Joncrill 62J) 10 parts by mass The coating solution was diluted with pure water to adjust the solid content to 15%.
Composition of coating solution 1 for hollow layer B (middle layer) Hollow particles (volume average particle size: 0.4 μm, average hollow ratio: 45%, manufactured by Rohm and Haas Co., Ltd., trade name: Ropeke ST) 60 parts by mass Gelatin (manufactured by Nitta Gelatin Co., Ltd., trade name: G1236) 28 parts by mass / binder resin (acrylic resin, Shin-Nakamura Chemical Co., Ltd., trade name: New Coat KT-1030) 5 parts by mass / binder resin ( Styrene / acrylic / acrylic acid resin, manufactured by BASF Japan Ltd., trade name: Jonkrill 62J) 8 parts by mass / SWC (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 0.2 parts by mass Was diluted with pure water to adjust the solid content to 19%.
Composition of coating solution 1 for hollow layer C (upper layer) Hollow particles (volume average particle diameter: 0.3 μm, average hollowness: 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) 18 parts by mass ・ Fluorescent whitening agent (made by Showa Chemical Co., Ltd., trade name: WN-1) 4 parts by mass ・ Binder resin (natural rubber latex / Methyl methacrylate graft polymerization emulsion, 67% addition of methyl methacrylate, manufactured by Residex Co., Ltd., trade name: Residex MG-67, 5 parts by mass, binder resin (styrene / acrylic / acrylic acid resin, manufactured by BASF Japan) , Trade name: Joncrill 62J) 3 parts by mass · SWC (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 0.2 parts by mass In addition, the coating solution is diluted with pure water, Solid content was adjusted to 22%.
Composition of Receptive Layer Coating Solution 1 Binder Resin 1 100 parts by weight Release Agent (Silicone Dispersion) 11 parts by weight Epoxy Crosslinking Agent (manufactured by Nagase ChemteX Corporation, trade name: Denacol EX512)
5 parts by mass / wax additive (Carnauba wax, manufactured by Chukyo Yushi Co., Ltd., trade name: Cellosol 524)
7 parts by mass / Thickener (made by ADEKA, trade name: UH-526) 4.5 parts by weight / Thickener (made by ADEKA, trade name: UH-540) 4.5 parts by weight / SWC (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 3 parts by mass The coating solution was diluted with pure water to adjust the solid content to 20%.

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.

The silicone dispersion used in the receiving 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. Then, the dispersion was desolvated under reduced pressure while warming to 30 to 60 ° C., the volume change of the desolvent was corrected by adding pure water, and the solid content was adjusted to 18%. 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

The coloring agent dispersion 1 used in the coating liquid 1 for the hollow layer A (lower layer) was dispersed as follows to prepare an aqueous dispersion. First, an aqueous solution 2 and a solvent-based solution 2 were prepared so as to have the following composition. The aqueous solution 2 and the solvent solution 2 were mixed and stirred, and then dispersed using a homogenizer to prepare a dispersion. Then, the dispersion was desolvated under reduced pressure while warming to 30 to 60 ° C., the volume change of the desolvent was corrected by adding pure water, and the solid content was adjusted to 18%. An aqueous dispersion was obtained.
Composition of aqueous solution 2 -Triisopropyl naphthalene sulfonic acid Na salt (dispersant, solid content 10%) 12 parts by mass-Gelatin (manufactured by Nitta Gelatin Co., Ltd., trade name: G1236) 67 parts by mass-500 parts by mass of pure water
Composition of solvent-based solution 2・ Binder and UV absorber (manufactured by Ciba Specialty Chemicals Co., Ltd., trade name: TINUVIN 1130) 27 parts by mass ・ Disperse dye (DISPERSE RED 60) 0.05 part by mass ・ Disperse dye (DISPERSE VIOLET 26) 0.10 parts by mass, disperse dye (DISPERSE BLUE 354) 0.05 parts by mass, 73 parts by mass of ethyl acetate

The details of the thickener used in the coating solution 1 for the receiving layer are shown in Table 1. The viscosity in the table is a viscosity measured at a liquid temperature of 25 ° C. according to JIS Z8803 using a B-type viscometer (model: BL Tokyo Keiki Co., Ltd.). The viscosity ratio in the table is the following formula (1):
Viscosity ratio = V _30,6 / V _30,60 (1)
(In the formula, V _30,6 is a viscosity (mPa.s) at a liquid temperature of 25 ° C. and a rotational speed of 6 rpm according to JIS Z8803 using a B-type viscometer (type: BL Tokyo Keiki Co., Ltd.). V _{30 and 60} show viscosity (mPa.s) at a liquid temperature of 25 ° C. and a rotation speed of 60 rpm in accordance with JIS Z8803 using a B-type viscometer)
It is a value represented by

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 hollow layer A (lower layer) was as follows.
Composition of hollow layer A (lower layer) coating solution 2 • Hollow particles (volume average particle size: 0.4 μm, average hollow ratio: 45%, manufactured by Rohm and Haas Co., Ltd., trade name: Ropeke ST) 55 parts by mass Colorant dispersion 1 25 parts by mass Binder resin (acrylic resin, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: New Coat KT-1030) 10 parts by mass Binder resin (methacrylic acid ester / acrylic acid resin, new Nakamura Chemical Co., Ltd., trade name: NKJ-300) 10 parts by mass The coating solution was diluted with pure water to adjust the solid content to 15%.

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 hollow layer A (lower layer) was as follows.
Composition of coating solution 3 for hollow layer A (lower layer) : Hollow particles (volume average particle size: 0.4 μm, average hollow ratio: 45%, manufactured by Rohm and Haas Co., Ltd., trade name: Ropeke ST) 55 parts by mass Colorant Dispersion Liquid 1 25 parts by mass Binder resin (styrene / acrylic / acrylic acid resin, manufactured by BASF Japan Ltd., trade name: Jonkrill 62J) 20 parts by mass In addition, the coating liquid was diluted with pure water, The solid content was adjusted to 15%.

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 2 Binder Resin 1 100 parts by weight Release Agent (Silicone Dispersion) 11 parts by weight Epoxy Crosslinking Agent (manufactured by Nagase ChemteX Corporation, trade name: Denacol EX512)
5 parts by mass / wax additive (paraffin wax, manufactured by Chukyo Yushi Co., Ltd., trade name: Torasol PF60) 7 parts by mass / thickening agent (trade name: UH-526, manufactured by ADEKA Corporation) 6 parts by mass / SWC (Dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 3 parts by mass The coating solution was diluted with pure water to adjust the solid content to 25%.

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 3 for receiving layer 100 parts by weight of binder resin 1 11 parts by weight of release agent (silicone dispersion) Epoxy crosslinking agent (manufactured by Nagase ChemteX Corporation, trade name: Denacol EX512)
5 parts by mass / wax additive (Carnauba wax, manufactured by Chukyo Yushi Co., Ltd., trade name: Cellosol 524)
7 parts by mass / Thickener (made by ADEKA Corporation, trade name: UH-526) 6 parts by mass / SWC (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 3 parts by mass The solid content was adjusted to 25%.

Example 6
Preparation of Thermal Transfer Image Receiving Sheet 6 A thermal transfer image receiving sheet 6 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the receiving layer was as follows.
Composition of Receptive Layer Coating Liquid 4 Binder Resin 1 100 parts by weight Release Agent (Silicone Dispersion) 11 parts by weight Epoxy Crosslinking Agent (manufactured by Nagase ChemteX Corporation, trade name: Denacol EX521)
5 parts by mass / wax additive (Carnauba wax, manufactured by Chukyo Yushi Co., Ltd., trade name: Cellosol 524)
7 parts by mass / Thickener (made by ADEKA Corporation, trade name: UH-526) 6 parts by mass / SWC (dioctylsulfosuccinic acid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 3 parts by mass The solid content was adjusted to 25%.

Comparative Example 1
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 hollow layer A (lower layer) was as follows.
Composition of coating liquid 4 for hollow layer A (lower layer) -25 parts by mass of colorant dispersion 1-Binder resin (acrylic resin, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: New Coat KT-1030) 10 parts by mass -Binder resin (styrene / acrylic / acrylic acid resin, manufactured by BASF Japan Ltd., trade name: Jonkrill 62J) 10 parts by mass The coating liquid was diluted with pure water to adjust the solid content to 15%.

Comparative Example 2
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 hollow layer A (lower layer) was as follows.
Composition of hollow layer A (lower layer) coating solution 5 Hollow particles (volume average particle size: 0.4 μm, average hollowness: 45%, manufactured by Rohm and Haas Co., Ltd., trade name: Ropeke ST) 55 parts by mass Colorant dispersion 1 25 parts by mass The coating solution was diluted with pure water to adjust the solid content to 15%.

Comparative Example 3
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 hollow layer A (lower layer) was as follows.
Composition of hollow layer A (lower layer) coating solution 6 · Hollow particles (volume average particle size: 0.4 µm, average hollow ratio: 45%, manufactured by Rohm and Haas Co., Ltd., trade name: Ropeke ST) 55 parts by mass Colorant dispersion 1 25 parts by mass Binder resin (manufactured by Nissin Chemical Industry Co., Ltd., trade name: VINYBRAN 278) 20 parts by mass The coating liquid was diluted with pure water to adjust the solid content to 15%. did.

Comparative Example 4
Preparation of thermal transfer image-receiving sheet 10 A thermal transfer image-receiving sheet 10 was prepared in the same manner as in Example 1 except that the composition of the coating solution for the hollow layer A (lower layer) was as follows.
Composition of coating solution 7 for hollow layer A (lower layer) Hollow particles (volume average particle size: 0.4 μm, average hollow ratio: 45%, manufactured by Rohm and Haas Co., Ltd., trade name: Ropeke ST) 55 parts by mass Colorant dispersion 2 25 parts by mass / binder resin (acrylic resin, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: New Coat KT-1030) 10 parts by mass / binder resin (styrene / acrylic / acrylic acid resin, BASF Japan Co., Ltd., trade name: Joncrill 62J) 10 parts by mass The coating solution was diluted with pure water to adjust the solid content to 15%.

An aqueous dispersion was prepared in the same manner as the coloring material dispersion 1, except that the coloring material dispersion 2 used in the coating solution 7 for the hollow layer A (lower layer) had the following composition.
Composition of aqueous solution 2-11 parts by mass of triisopropyl naphthalene sulfonic acid Na salt (dispersant, solid content 10%)-Gelatin (manufactured by Nitta Gelatin Co., Ltd., trade name: G1236) 67 parts by mass-470 parts by mass of pure water
Composition of solvent-based solution 2 , binder and ultraviolet absorber (manufactured by Ciba Specialty Chemicals Co., Ltd., trade name: TINUVIN 1130) 27 parts by mass, ethyl acetate 73 parts by mass

Evaluation of Thermal Transfer Image Receiving Sheet The thermal transfer image receiving sheet prepared above was subjected to (1) image density evaluation, (2) image storage stability evaluation, and (3) releasability 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. Similarly, an 11 gradation gradation image was printed and showed an OD value (optical density) of black.

(2) Evaluation of surface quality By visually observing the thermal transfer image-receiving sheet prepared as described above, the following criteria were used.
Evaluation criteria : ○: No unevenness was observed in the coating surface quality.
-: Unevenness was not recognized at first glance, but slightly unevenness was observed when viewed close to each other.
-X: Printing unevenness was recognized at first glance.
(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) Whiteness evaluation A sublimation type thermal transfer printer (manufactured by ALTECH ADS, model: MEGAPIXEL III) and an ink ribbon (for Megapixel III, Altech AD S Co., Ltd. genuine product) are applied to the thermal transfer image-receiving sheet prepared above. Used to print a solid white image. The obtained printed matter was visually evaluated.
Evaluation criteria : ○: Appearance was not yellowish and white, Δ: Appearance was yellowish, but at a satisfactory level. ×: Appearance was yellow.

Table 2 shows the results of the above evaluations. The thermal transfer image receiving sheets of Examples 1 to 6 satisfying the composition of the present invention are excellent in various performances such as image density, image storage stability, and releasability as compared with the thermal transfer image receiving sheets of Comparative Examples 1 to 4. I understand that.

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

Claims (4)

A thermal transfer image receiving sheet comprising a base material, at least three hollow layers on the base material, and a receiving layer in this order,
The thermal transfer image-receiving sheet, wherein the lowermost layer of the at least three hollow layers comprises hollow particles, an acrylic resin, and a coloring agent.   The thermal transfer image-receiving sheet according to claim 1, wherein all of the at least three hollow layers further contain gelatin.   The thermal transfer image-receiving sheet according to claim 1 or 2, wherein the receptor layer comprises a binder resin, a wax additive, and a urethane-associative thickener.   The thermal transfer image-receiving sheet according to any one of claims 1 to 3, wherein all the layers constituting the surface side having the receiving layer of the substrate are formed by aqueous coating.

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