JP2008238735A - Thermal transfer image-receiving sheet and method for producing the same - Google Patents

Abstract

A thermal transfer image-receiving sheet having high smoothness and no white spot failure is provided.
The support has at least one heat insulating layer containing at least one hollow polymer, at least one receiving layer containing at least one polymer latex, and at least two layers are formed by simultaneous multilayer coating. The heat-sensitive transfer image-receiving sheet is dried by at least two or more apparatuses capable of setting at least two or more different temperature and humidity conditions after coating, and the reduced rate drying rate at the time of drying is 0 of the constant rate drying rate. A thermal transfer image-receiving sheet of 2 to 0.8 times.
[Selection figure] None

Description

  The present invention relates to a heat-sensitive transfer image-receiving sheet and a method for producing the same, and more particularly to a heat-sensitive transfer image-receiving sheet with little curling and a method for producing the same.

  Conventionally, various thermal transfer recording methods are known, and among them, the dye diffusion transfer recording method is attracting attention as a process capable of producing a color hard copy closest to the image quality of a silver salt photograph (for example, Non-Patent Document 1 and 2). In addition, it has the advantages of being dry, being able to visualize directly from digital data, and being easy to duplicate, compared to silver salt photography.

  In this dye diffusion transfer recording system, a thermal transfer sheet containing a pigment (hereinafter also referred to as an ink sheet) and a thermal transfer image receiving sheet (hereinafter also referred to as an image receiving sheet) are superposed, and then heat is generated by an electrical signal. By heating the ink sheet with a controlled thermal head, the dye in the ink sheet is transferred to the image receiving sheet to record image information. By recording three colors of cyan, magenta, and yellow in an overlapping manner, A color image having a continuous change in color shading can be transferred and recorded.

  Ordinary paper can be used as the support for the image receiving sheet of this system, and it can be manufactured at low cost. In order to supplement the cushioning property of the support, the image-receiving sheet using such paper as a support is usually a highly cushioning layer between the support and the receiving layer, for example, a foamed layer composed of a resin and a foaming agent. Is formed to give cushioning properties and enhance the adhesion between the image receiving sheet and the transfer sheet. Further, an intermediate layer is further provided between the foam layer and the receiving layer to prevent the foam layer from being crushed by heating during printing. However, in the conventional image receiving sheet, since this intermediate layer is formed of an organic solvent-based resin coating liquid, the coating liquid crushes bubbles and voids in the foam layer, and a desired cushioning property is obtained. In general, white spots and density unevenness occur during image formation, and the heat insulation necessary for the transfer of the dye is diffused toward the back side of the image-receiving sheet, resulting in a decrease in sensitivity during printing. There was a problem of inviting.

  On the other hand, for example, Patent Document 1 discloses that an intermediate layer between the foam layer and the receiving layer is formed by a water-based coating liquid, and the fine irregularities of the foam layer are directly used as the surface shape of the receiving layer. However, in this method, since the foamed layer is applied on the support and the receptor layer is applied after being heated and dried, irregularities are formed on the surface of the receptor layer, so that many image defects occur. In addition, there is a problem that the sensitivity is insufficient and the cost is high. For example, Patent Document 2 discloses that an intermediate layer mainly composed of hollow particles and an organic solvent-resistant polymer is formed between a support and a receiving layer. For example, Patent Document 3 discloses a dye. Although it is disclosed that a resin layer including a receiving layer contains a hollow capsule, these methods similarly apply an accepting layer after applying an intermediate layer or a resin layer and drying it by heating. Since irregularities are formed on the surface of the layer, there are many image defects, and there is a problem that film peeling occurs depending on how to handle because the interlayer adhesion is not sufficient. Furthermore, there is a problem that the sensitivity is insufficient and the cost is high. Further, in Patent Document 4, in order to solve the above problem, an attempt is made to achieve both sensitivity and unevenness failure by simultaneous multilayer coating. However, in a coating solution having a high solid content concentration and a small amount of binder, drying is performed. Previously, the viscosity of the coating solution increased excessively and was fixed before unevenness during coating was made uniform, and the problem of image defects (especially white spot failure in the print area) could not be solved.

JP-A-8-25813 Japanese Patent Laid-Open No. 11-321128 Japanese Patent Laid-Open No. 5-147364 Japanese Patent Laid-Open No. 2006-68718 “New development of information recording (hard copy) and its materials”, published by Toray Research Center, Inc., 1993, p. 241-285 “Development of printer materials”, issued by CMC Co., Ltd., 1995, p. 180

  It is intended to provide a thermal transfer image-receiving sheet that has an aqueous simultaneous multi-layer coating, a high solid content concentration in the lower layer, at least a binder amount, high smoothness, and no white spot failure.

  As a result of intensive studies, the inventors have at least one heat insulating layer containing at least one hollow polymer on the support, at least one receiving layer containing at least one polymer latex, and at least 2 layers. A heat-sensitive transfer image-receiving sheet having a layer formed by simultaneous multilayer coating, dried by at least two or more apparatuses capable of setting at least two different temperature and humidity conditions after coating, and reduced rate drying speed at the time of the drying However, it has been found that the thermal transfer image-receiving sheet has good curl, which is 0.2 to 0.8 times the constant rate drying rate. The present invention has been made based on such findings.

The above problems have been achieved by the following means.
(1) The support has at least one heat insulating layer containing at least one hollow polymer, at least one receiving layer containing at least one polymer latex, and at least two layers are formed by simultaneous multilayer coating. The thermal transfer image-receiving sheet is dried by at least two or more apparatuses capable of setting at least two or more different temperature and humidity conditions after coating, and the reduction rate drying rate at the time of drying is 0. Thermal transfer image receiving sheet, characterized in that it is 2 to 0.8 times;
(2) The polymer latex contained in the receiving layer is any one of vinyl chloride / acrylic compound copolymer latex, vinyl chloride / vinyl acetate copolymer latex, vinyl chloride / vinyl acetate / acrylic compound copolymer latex, or The thermal transfer image-receiving sheet according to item (1), which is an arbitrary combination,
(3) The support has at least one heat insulating layer containing at least one hollow polymer, at least one receiving layer containing at least one polymer latex, and at least two layers are formed by simultaneous multilayer coating. A method for producing a heat-sensitive transfer image-receiving sheet, which is dried by at least two devices capable of setting at least two different temperature and humidity conditions after coating, and the reduced rate drying rate at the time of drying is a constant rate drying rate. And (4) a polymer latex contained in the receptor layer is a vinyl chloride / acrylic compound copolymer latex, vinyl chloride / It can be any one or any combination of vinyl acetate copolymer latex, vinyl chloride / vinyl acetate / acrylic compound copolymer latex. Wherein (3) the heat-sensitive transfer image-receiving sheet manufacturing method according to claim, characterized in.

  The heat-sensitive transfer image-receiving sheet of the present invention has a small curl and can be produced at a low cost. Further, the thermal transfer image receiving sheet of the present invention can prevent the occurrence of white spot failure.

Hereinafter, the present invention will be described in detail.
The heat-sensitive image-receiving sheet of the present invention has at least one heat-insulating layer containing at least one hollow polymer on the support, at least one receiving layer containing at least one polymer latex, and at least two layers simultaneously laminated. It is formed by coating. Further, an intermediate layer such as a white background adjusting layer, a charge adjusting layer, an adhesive layer, a primer layer, or an undercoat layer may be formed between the support and the heat insulating layer. When the intermediate layer is included, the receiving layer, the heat insulating layer, and the intermediate layer can be formed by simultaneous multilayer coating. A release layer may be formed on the outermost layer on the surface on which the transfer material is superposed.
Furthermore, a curl adjusting layer, a writing layer, and a charge adjusting layer are preferably formed on the back side of the support.

  The production process of these heat-sensitive image-receiving sheets includes adjustment of the coating solution, coating of the coating solution on the support, and drying. The receiving layer and the heat-insulating layer are each preferably two or more layers, or one of them is a two-layer or more. However, if at least the adjacent constituent layers are both water-based, these layers can be applied simultaneously. preferable. In particular, in the above, the adjacent layers are preferably a receiving layer and a heat insulating layer.

Hereinafter, this process will be described in detail.
(Preparation of coating solution)

(Application)
Each layer can be applied by appropriately selecting from known methods such as roll coating, bar coating, gravure coating, gravure reverse coating, die coating, slide coating, curtain coating, etc. The coating is a method in which the coating film thickness is determined by the flow rate of liquid delivered by a pump or the like.
When producing a multi-layer image receiving sheet comprising a plurality of layers having different functions (such as a bubble layer, a heat insulating layer, an intermediate layer, and a receiving layer) on a support, JP-A Nos. 2004-106283 and 2004-181888 are disclosed. In addition, it is known that each layer is sequentially coated as disclosed in each publication such as JP-A 2004-345267, or the layers are previously applied on a support and bonded together. On the other hand, it is known in the photographic industry that productivity is greatly improved, for example, by applying a plurality of layers simultaneously. For example, JP-A Nos. 2,761,791, 2,681,234, 3,508,947, 4,457,256, 3,993,019, Kaisho 63-54975, JP-A-61-278848, 55-86557, 52-31727, 55-142565, 50-43140, 63-80872, 54-54020 JP-A-5-104061, JP-A-5-127305, JP-B49-7050, or the specification of Edgar B. et al. The so-called slide coating method (slide coating method) and curtain coating method (curtain coating method) described in Guoff et al., “Coating and Drying Defects: Troubleshooting Operating Problems”, John Wiley & Sons, 1995, pages 101 to 103, etc. Are known. In these coating methods, a plurality of coating liquids are simultaneously supplied to a coating apparatus to form a plurality of different layers. These methods are preferred embodiments of the present invention because a uniform coating film thickness can be obtained and multilayer simultaneous coating is possible.
As an apparatus for the slide coating method, there is a multilayer slide bead apparatus proposed in US Pat. No. 2,761,791 by Russell et al. This device forms a bead in the gap where a plurality of coating liquids flowing down the slide surface meet the support that is continuously running at the tip of the slide surface, and the coating liquid is applied to the support surface via the bead. To do. Therefore, it is important for this type of apparatus to be able to form beads stably. An example of the shape of a slide coater is Stephen F. et al. Kistler, Petert. It is also described in “LIQUID FILM COATING” written by Schweizer (CHAPMAN & HALL, 1997).
Curtain coating is a method of coating a free-falling liquid film on a support that is continuously running at a constant speed below. There are several methods such as an extrusion type and a slide type. In the slide type coater, the multilayer liquid film created on the slide surface falls freely from the slide end. Therefore, the shape of the slide surface is devised so that a falling liquid film is smoothly formed.
In simultaneous multi-layer coating, it is necessary to adjust the viscosity and surface tension of the coating solution constituting each layer from the viewpoints of forming a uniform coating film and good coating properties. The viscosity of the coating solution can be easily adjusted by using a known thickener or thickener within a range that does not affect other performances. Further, the surface tension of the coating solution can be adjusted by various surfactants.
In order to feed a coating solution prepared so that the physical properties such as liquid concentration, viscosity, surface tension, pH, etc. are appropriate values, it is necessary to continuously carry out while removing bubbles and foreign substances. is there.
Various methods are possible for continuously supplying the coating liquid at a constant flow rate, but it is preferable to use a metering pump from the viewpoint of accuracy and reliability. Examples include a plunger pump and a diaphragm pump. In the diaphragm type, the plunger and the liquid to be sent are separated by the two diaphragms, and the operation of the plunger is transmitted to the liquid to be sent via the drive oil and the pure water between the two diaphragms. It is done. Variations in the flow rate of the liquid feed pump lead to variations in the coating film thickness, and sufficient accuracy is required.
When it is necessary to reduce the influence of the pump pulsation, an auxiliary device for absorbing the pulsation is used. Some methods are known, but one example is a pipeline type pulsation absorbing device (JP-A-1-255793).
In order to remove foreign matter, it is preferable to filter the coating solution. Various kinds of filter media can be used, and a cartridge filter medium can be given as an example. In use, it is preferable to treat in advance in order to prevent air retained in the pores of the filter medium from being mixed into the coating liquid in the form of bubbles. Although several methods are known, as an example, treatment with a liquid containing a surfactant or the like (US Pat. No. 5,096,602) can be mentioned.
Along with foreign matter, bubbles also cause coating surface failure. For this reason, it is preferable to defoam and defoam bubbles that are mixed in the coating liquid and foams that are floating on the liquid surface. As a technique for this purpose, there is separation of bubbles from liquid or dissolution of bubbles in liquid. As separation methods, vacuum defoaming, ultrasonic defoaming, centrifugal defoaming and the like are known. Examples of the method for dissolving in a liquid include ultrasonic pipeline defoaming.
When using an additive that deteriorates the aging stability of the coating solution by adding it to the coating solution, in order to shorten the aging time from adding to coating, A method of adding just before is known. Such a method can also be used in the present invention. As a mixer for this purpose, there are a static mixer and a dynamic mixer.

(Dry)
After coating, the coated product having a coating film formed on the support is dried in a drying zone and wound up through a humidity control zone. In the present invention, it is preferable to quickly solidify after forming a laminate of a plurality of layers on a support. As an example, in the case of a multilayer structure solidified by a resin, it is preferable to quickly raise the temperature after forming a plurality of layers on the support. When strong drying air is applied at a stage where the coating film is not sufficiently solidified, fluidity is generated, resulting in unevenness. Further, when the uppermost layer of the coating film contains an organic solvent, nonuniform solvent evaporation occurs on the slide surface or immediately after coating due to the wind, resulting in unevenness. From this point of view, aqueous coating is advantageous.
In addition, when a binder that gels at a low temperature such as gelatin is included, it may be preferable to form a plurality of layers on a support and then quickly lower the temperature to cool and solidify the coating, then raise the temperature and dry. . Thereby, a further uniform and homogeneous coating film is formed. Here, the setting step is, for example, a gelation accelerating step for increasing the viscosity of the coating composition by means of lowering the temperature by applying cold air or the like to the coating and slowing the material fluidity in each layer and each layer. Means that.
The temperature condition when using cold air is preferably 25 ° C. or lower, and more preferably 10 ° C. or lower.
In the set zone and the drying zone, moisture movement occurs between each coating film and between the support and the coating film, and the coating film is cooled and solidified by moisture evaporation. For this reason, the history of the film surface temperature and drying time during the drying greatly affects the quality and performance of the product such as curl and whiteout failure, and it is necessary to set conditions according to the required quality.
In the present invention, since the latex mainly constitutes the coating solution, if it is dried quickly, the film shrinks due to drying, resulting in cracks in the coated film after drying, and it is preferable to dry slowly. In order to satisfy these requirements, the drying process needs to be dried while adjusting the drying speed, adjusting the drying temperature, the amount of drying air, and the dew point of the drying air.
As a typical drying apparatus, there are an air loop method, a hanger method, and the like. The air loop method is a method in which a dry air jet is blown onto a coated product supported by a roller, and there are a method in which a duct is arranged vertically and a method in which a duct is arranged horizontally. The drying function and the transport function are basically separated, and the degree of freedom such as the air volume is large. However, since many rollers are used, poor conveyance of the base such as slippage, wrinkles, and slips is likely to occur. The spiral winding method is a method in which a coated product is wound around a cylindrical duct in a spiral shape and floated with dry air (air floating), and transported and dried. 20438). In the present invention, these drying apparatuses can be preferably used.
In the drying zone, the drying rate is constant, the drying rate is constant and the wet bulb temperature is approximately equal to the constant rate drying period, and the drying rate is slowed and the drying rate is increased, and the drying rate is increased. move on. In the constant rate drying period, all external heat is used to evaporate moisture. During the rate-decreasing drying period, moisture diffusion inside the material becomes rate-limiting, and the drying rate decreases due to the receding of the evaporation surface, etc., and the applied heat is used for increasing the material temperature. In the present invention, the decreasing rate of drying is preferably 0.8 to 0.2 times the constant rate drying rate, and more preferably 0.8 to 0.3 times.

Hereinafter, the configuration of the heat-sensitive image-receiving sheet of the present invention will be described in detail.
(Receptive layer)
The receiving layer serves to receive the dye transferred from the ink sheet and maintain the formed image. In the image receiving sheet of the present invention, the receiving layer contains a polymer latex.
The receiving layer can contain an ultraviolet absorber, a release agent, a lubricant, an antioxidant, a preservative, a surfactant, and other additives.

<Polymer latex>
The polymer latex used in the present invention will be described. In the heat-sensitive transfer image-receiving sheet of the present invention, the polymer latex that can be used in the receptor layer is a water-insoluble hydrophobic polymer dispersed as fine particles in a water-soluble dispersion medium. As the dispersion state, the polymer is emulsified in a dispersion medium, the emulsion is polymerized, the micelle is dispersed, or the polymer molecule has a partially hydrophilic structure and the molecular chain itself is molecularly dispersed. Anything may be used. For polymer latex, Tadashi Okuda, Hiroshi Inagaki, “Synthetic Resin Emulsion”, published by Kobunshi Publishing (1978), Takaaki Sugimura, Ikuo Kataoka, Junichi Suzuki, Keiji Kasahara, “Application of Synthetic Latex”, Takashi Published by Molecular Press (1993), Soichi Muroi, “Synthetic Latex Chemistry”, published by High Polymer Press (1970), supervised by Yoshiaki Mitsuzawa, “Development and application of water-based coating materials”, CM Publishing ( 2004) and JP-A-64-538. The average particle size of the dispersed particles is preferably 1 to 50000 nm, more preferably about 5 to 1000 nm.
The particle size distribution of the dispersed particles is not particularly limited, and may have a wide particle size distribution or a monodispersed particle size distribution.

  The polymer latex may be a so-called core / shell type latex in addition to a normal uniform polymer latex. In this case, it may be preferable to change the glass transition temperature between the core and the shell. The glass transition temperature (Tg) of the polymer latex of the present invention is preferably -30 ° C to 130 ° C, more preferably 0 ° C to 120 ° C. Among these, the glass transition temperature is preferably 40 ° C or higher (preferably 40 to 120 ° C), and more preferably 70 ° C or higher (70 to 100 ° C).

  Preferred embodiments of the polymer latex of the present invention include polymer latexes such as acrylic polymers, polyesters, rubbers (for example, SBR resin), polyurethanes, polyvinyl chlorides, polyvinyl acetates, polyvinylidene chlorides, and polyolefins. Can be preferably used. The polymer latex may be a linear polymer, a branched polymer, a crosslinked polymer, a so-called homopolymer obtained by polymerizing a single monomer, or a copolymer obtained by polymerizing two or more monomers. Good. In the case of a copolymer, it may be a random copolymer or a block copolymer. These polymers have a number average molecular weight of 5,000 to 1,000,000, preferably 10,000 to 500,000. If the molecular weight is too small, the mechanical strength of the layer containing the latex is insufficient, and if it is too large, the film formability is poor and this is not preferred. A crosslinkable polymer latex is also preferably used.

  The monomer used for the synthesis of the polymer latex used in the present invention is not particularly limited, and monomers that can be polymerized by a normal radical polymerization or ionic polymerization method are preferably the following monomer groups (a) to (j). Can be used. Polymer monomers can be synthesized by selecting these monomers independently and freely in combination.

-Monomer group (a)-(j)-
(A) Conjugated dienes: 1,3-pentadiene, isoprene, 1-phenyl-1,3-butadiene, 1-α-naphthyl-1,3-butadiene, 1-β-naphthyl-1,3-butadiene, cyclo Pentadiene and the like.
(B) Olefins: ethylene, propylene, vinyl chloride, vinylidene chloride, 6-hydroxy-1-hexene, 4-pentenoic acid, methyl 8-nonenoate, vinylsulfonic acid, trimethylvinylsilane, trimethoxyvinylsilane, 1,4- Divinylcyclohexane, 1,2,5-trivinylcyclohexane, etc.

  (C) α, β-unsaturated carboxylic acid esters: alkyl acrylate (eg, methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, etc.), substituted alkyl acrylate (eg, 2-chloro Ethyl acrylate, benzyl acrylate, 2-cyanoethyl acrylate, etc.), alkyl methacrylate (eg, methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, etc.), substituted alkyl methacrylate (eg, 2-hydroxyethyl methacrylate, glycidyl methacrylate, glycerin) Monomethacrylate, 2-acetoxyethyl methacrylate, tetrahydrofurfuryl meta Relate, 2-methoxyethyl methacrylate, polypropylene glycol monomethacrylate (polyoxypropylene added mole number = 2 to 100), 3-N, N-dimethylaminopropyl methacrylate, chloro-3-N, N, N-trimethyl Ammoniopropyl methacrylate, 2-carboxyethyl methacrylate, 3-sulfopropyl methacrylate, 4-oxysulfobutyl methacrylate, 3-trimethoxysilylpropyl methacrylate, allyl methacrylate, 2-isocyanatoethyl methacrylate, etc.), unsaturated dicarboxylic acid derivatives (For example, monobutyl maleate, dimethyl maleate, monomethyl itaconate, dibutyl itaconate, etc.), polyfunctional esters (for example, ethylene glycol diacrylate, Tylene glycol dimethacrylate, 1,4-cyclohexanediacrylate, pentaerythritol tetramethacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, dipentaerythritol pentamethacrylate, pentaerythritol hexaacrylate, 1,2, 4-cyclohexanetetramethacrylate and the like.

(D) Amides of α, β-unsaturated carboxylic acid: for example, acrylamide, methacrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N-methyl-N-hydroxyethylmethacrylamide, N-tert-butylacrylamide N-tert-octylmethacrylamide, N-cyclohexylacrylamide, N-phenylacrylamide, N- (2-acetoacetoxyethyl) acrylamide, N-acryloylmorpholine, diacetone acrylamide, itaconic acid diamide, N-methylmaleimide, 2 -Acrylamide-methylpropane sulfonic acid, methylene bisacrylamide, dimethacryloyl piperazine and the like.
(E) Unsaturated nitriles: acrylonitrile, methacrylonitrile and the like.
(F) Styrene and its derivatives: styrene, vinyl toluene, p-tert-butyl styrene, vinyl benzoic acid, methyl vinyl benzoate, α-methyl styrene, p-chloromethyl styrene, vinyl naphthalene, p-hydroxymethyl styrene, p -Styrene sulfonic acid sodium salt, p-styrene sulfinic acid potassium salt, p-aminomethylstyrene, 1,4-divinylbenzene and the like.
(G) Vinyl ethers: methyl vinyl ether, butyl vinyl ether, methoxyethyl vinyl ether, and the like.
(H) Vinyl esters: vinyl acetate, vinyl propionate, vinyl benzoate, vinyl salicylate, vinyl chloroacetate, and the like.
(I) α, β-unsaturated carboxylic acid and salts thereof: acrylic acid, methacrylic acid, itaconic acid, maleic acid, sodium acrylate, ammonium methacrylate, potassium itaconate and the like.
(J) Other polymerizable monomers: N-vinylimidazole, 4-vinylpyridine, N-vinylpyrrolidone, 2-vinyloxazoline, 2-isopropenyloxazoline, divinylsulfone, and the like.

  The polymer latex that can be used in the present invention is commercially available, and the following polymers can be used. Examples of the acrylic polymer include Sebian A-4635, 4718, 4601 manufactured by Daicel Chemical Industries, Ltd., Nipol Lx811, 814, 821, 820, 855 manufactured by Nippon Zeon Co., Ltd. (P-17: Tg 36 ° C.), 857 × 2 (P-18: Tg 43 ° C.), Voncoat R3370 (P-19: Tg 25 ° C.), 4280 (P-20: Tg 15 ° C.) manufactured by Dainippon Ink & Chemicals, Jurimer ET-410 (manufactured by Nippon Pure Chemical Co., Ltd.) P-21: Tg44 ° C), AE116 (P-22: Tg50 ° C) manufactured by JSR Corporation, AE119 (P-23: Tg55 ° C), AE121 (P-24: Tg58 ° C), AE125 (P-25: Tg60) ° C), AE134 (P-26: Tg48 ° C), AE137 (P-27: Tg48 ° C), AE140 (P-28: Tg53 ° C) ), AE173 (P-29: Tg 60 ° C.), Toagosei Co., Ltd. Aron A-104 (P-30: Tg 45 ° C.), Takamatsu Yushi Co., Ltd. NS-600X, NS-620X, Nissin Chemical Industry ( Vinibrand 2580, 2583, 2641, 2770, 2770H, 2635, 2886, 5202C, 2706, etc. manufactured by Co., Ltd. (all are trade names).

Examples of polyesters include: FINETENX ES650, 611, 675, 850 manufactured by Dainippon Ink Chemical Co., Ltd., WD-size, WMS manufactured by Eastman Chemical, A-110, A-115GE manufactured by Takamatsu Yushi Co., Ltd., A- 120, A-21, A-124GP, A-124S, A-160P, A-210, A-215GE, A-510, A-513E, A-515GE, A-520, A-610, A-613, A-615GE, A-620, WAC-10, WAC-15, WAC-17XC, WAC-20, S-110, S-110EA, S-111SL, S-120, S-140, S-140A, S- 250, S-252G, S-250S, S-320, S-680, DNS-63P, NS-122L
NS-122LX, NS-244LX, NS-140L, NS-141LX, NS-282LX, Aronmelt PES-1000 series, PES-2000 series, Toyobo Co., Ltd. Bironal MD-1100, MD- 1200, MD-1220, MD-1245, MD-1250, MD-1335, MD-1400, MD-1480, MD-1500, MD-1930, MD-1985, Sepijon ES manufactured by Sumitomo Seika Co., Ltd. (Both are trade names).

  Examples of polyurethanes include HYDRAN AP10, AP20, AP30, AP40, 101H, Vonic 1320NS, 1610NS, manufactured by Dainippon Ink and Chemicals, Inc., D-1000, D-2000, D-6000, manufactured by Dainichi Seika Co., Ltd. Examples include D-4000, D-9000, NS-155X, NS-310A, NS-310X, NS-311X manufactured by Takamatsu Yushi Co., Ltd., and Elastron manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (all trade names).

  Examples of rubbers include LACSTAR 7310K, 3307B, 4700H, 7132C (manufactured by Dainippon Ink and Chemicals), Nipol Lx416, LX410, LX430, LX435, LX110, LX415A, LX438C, 2507H, LX303A, LX407BP series, V1004, MH5055 (manufactured by Nippon Zeon Co., Ltd.) and the like (all are trade names).

  As an example of polyvinyl chloride, Nippon Zeon Co., Ltd. G351, G576, Nissin Chemical Industry Co., Ltd. Vinibrand 240, 270, 277, 375, 386, 609, 550, 601, 602, 630, 660, 671, 683, 680, 680S, 681N, 685R, 277, 380, 381, 410, 430, 432, 860, 863, 865, 867, 900, 900GT, 938, 950, etc. (all are trade names). Examples of polyvinylidene chlorides include L502 and L513 manufactured by Asahi Kasei Kogyo Co., Ltd., D-5071 manufactured by Dainippon Ink and Chemicals, Inc. (all are trade names). Examples of polyolefins include Chemipearl S120, SA100, V300 (P-40: Tg 80 ° C.) manufactured by Mitsui Petrochemical Co., Ltd., Voncoat 2830, 2210, 2960 manufactured by Dainippon Ink Chemical Co., Ltd., Sumitomo Seika Co., Ltd. Examples of Zyxen, Sepoljon G, and copolymerized nylons include Sepoljon PA manufactured by Sumitomo Seika Co., Ltd. (all are trade names).

  Examples of the polyvinyl acetates include Nibsin Chemical Industry Co., Ltd. Vinibrand 1080, 1082, 1085W, 1108W, 1108S, 1563M, 1566, 1570, 1588C, A22J7-F2, 1128C, 1137, 1138, A20J2, A23J1, A23J1, A23K1, A23P2E, A68J1N, 1086A, 1086A, 1086D, 1108S, 1187, 1241LT, 1580N, 1083, 1571, 1572, 1581, 4465, 4466, 4468W, 4468S, 4470, 4485LL, 4495LL, 1023, 1042, 1060, 1060S, 1080M, 1084W, 1084S, 1096, 1570K, 1050, 1050S, 3290, 1017AD, 1002, 1006, 1008, 107L, 1225,1245L, GV-6170, GV-6181,4468W, such as 4468S, and the like (all trade names).

These polymer latexes may be used alone or in combination of two or more as required. The polymer latex of the present invention may be any one or any combination of vinyl chloride / acrylic compound copolymer latex, vinyl chloride / vinyl acetate copolymer latex, vinyl chloride / vinyl acetate / acrylic compound copolymer latex. Preferably, vinyl chloride / acrylic compound copolymer latex is most preferable.
The preferred polymer latex here is preferably one that is compatible with the dye in order to accept the dye that migrates from the ink sheet, while being difficult to be compatible with the binder in which the dye of the ink sheet is dispersed. Is preferred. When a polymer latex that is compatible with the dye is used, the maximum transfer density is increased and an image having a sharp image can be obtained. When a polymer latex that is compatible with the binder in which the dye of the ink sheet is dispersed is used, peeling noise is likely to occur when the ink sheet and the thermal transfer receiving sheet are heated after being overlapped. The easier the polymer latex is compatible, the greater the peeling noise, and eventually the peeling line (banding) occurs when the ink sheet peels.

  In the present invention, at least one receiving layer is applied with an aqueous coating solution. When a plurality of receiving layers are provided, all of these receiving layers should be prepared by applying an aqueous coating solution and then drying. Is preferred. However, “aqueous” as used herein means that 60% by mass or more of the solvent (dispersion medium) of the coating solution is water. Components other than water in the coating solution include methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, ethyl acetate, diacetone alcohol, furfuryl alcohol, benzyl alcohol, diethylene glycol monoethyl ether, oxyethyl phenyl ether A water miscible organic solvent such as can be used.

  The minimum film-forming temperature (MFT) of the polymer latex is preferably −30 ° C. to 90 ° C., more preferably about 0 ° C. to 70 ° C.

  Preferable examples of the polymer latex used in the present invention include polylactic acid esters, polyurethanes, polycarbonates, polyesters, polyacetals, SBRs, and polyvinyl chlorides. Among these, polyesters, polycarbonates Most preferably, polyvinyl chlorides are included.

In the present invention, among the above polymer latexes, polyvinyl chlorides are preferred in the present invention. Among the polyvinyl chlorides, that is, the polymer latex containing at least a repeating unit obtained from vinyl chloride, a polymer latex containing 50 mol% or more of a repeating unit obtained from the vinyl chloride is preferable, and a copolymerized polymer latex is more preferable. It is. As such a copolymer latex, it is preferable that the monomer copolymerized with vinyl chloride is acrylic or methacrylic acid or an ester thereof, vinyl acetate or ethylene. Also preferred are vinyl chlorides and copolymers of acrylic and vinyl acetate. Acrylic or methacrylic acid or its ester is more preferred, and acrylic acid ester is more preferred. The alcohol part of the ester part of the acrylate ester preferably has 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms.
Examples of such polyvinyl chlorides include those mentioned above, among others, ViniBran 240, ViniBran 270, ViniBran 276, ViniBran 277, ViniBran 375, ViniBran 380, ViniBran 386, ViniBran 410, ViniBran 430, ViniBran 432, VINYBRAN 550, VINYBRAN 601, VINYBRAN 602, VINYBRAN 609, VINYBRAN 619, VINYBRAN 680, VINYBRAN 680S, VINYBRAN 681N, VINYBRAN 683, VINYBRAN 685R, VINYBRAN 690, VINYBRAN 860, VINYBRAN 863, VINYBRAN 685, VINYBRAN 867, VINYBRAN 900, , ViniBran 950 (all are Nissin Chemical Industry Co., Ltd., SE1320, S-830 (all are Sumitomo Chemtech ( )) Is preferable.

The polymer latex used in the present invention is used for receiving the dye that migrates from the ink sheet, but any polymer may be used in combination with the polymer latex.
The polymer that can be used in combination may be used for receiving a dye, but may also be used as a binder for holding the polymer latex.
Such polymers are preferably transparent or translucent and colorless, and are natural resins, polymers and copolymers, synthetic resins, polymers and copolymers, and other media forming films such as gelatins, polyvinyl alcohols, hydroxys. Ethyl cellulose, cellulose acetate, cellulose acetate butyrate, polyvinyl pyrrolidone, casein, starch, polyacrylic acid, polymethyl methacrylic acid, polyvinyl chloride, polymethacrylic acid, styrene-maleic anhydride copolymers, styrene -Acrylonitrile copolymers, styrene-butadiene copolymers, polyvinyl acetals (eg, polyvinyl formal and polyvinyl butyral), polyesters, polyurethanes, phenoxy resins, poly salts Vinylidene, polyepoxides, polycarbonates, polyvinyl acetates, polyolefins, and polyamides. The binder may be coated from water or an organic solvent or emulsion.

  In addition to the polymer latex used for the purpose of accepting the dye migrating from the ink sheet, when using a polymer latex mainly used as the binder, the polymer latex has processing brittleness and image storage stability. The glass transition temperature (Tg) is preferably in the range of -30 ° C to 70 ° C, more preferably in the range of -10 ° C to 50 ° C, still more preferably in the range of 0 ° C to 40 ° C. It is also possible to use a blend of two or more polymers as the binder, and in this case, it is preferable that the weighted average Tg in consideration of the composition falls within the above range. Moreover, when phase-separating or having a core-shell structure, the weighted average Tg is preferably within the above range.

This glass transition temperature (Tg) can be calculated by the following formula.
1 / Tg = Σ (Xi / Tgi)
Here, it is assumed that n monomer components from i = 1 to n are copolymerized in the polymer. Xi is the weight fraction of the i-th monomer (ΣXi = 1), and Tgi is the glass transition temperature (absolute temperature) of the homopolymer of the i-th monomer. However, Σ is the sum from i = 1 to n. The homopolymer glass transition temperature value (Tgi) of each monomer may be the value of “Polymer Handbook (3rd Edition)” (J. Brandrup, EH Immergut (Wiley-Interscience, 1989)).
In addition, although the glass transition temperature of the said polymer latex for receiving the dye in this invention and the hollow polymer mentioned later is prescribed | regulated by a measured value, it is also possible to estimate with said calculation method.

<Water-soluble polymer>
In the present invention, it is one of preferred embodiments that the receiving layer contains a water-soluble polymer.
Here, the water-soluble polymer may be dissolved in an amount of 0.05 g or more with respect to 100 g of water at 20 ° C., more preferably 0.1 g or more, still more preferably 0.5 g or more, and particularly preferably 1 g or more. The polymer latex is obtained by dispersing polymer fine particles in a dispersion medium, and is different from the water-soluble polymer of the present invention.
Water-soluble polymers that can be used in the present invention include natural polymers (polysaccharides, microorganisms, animals), semi-synthetic polymers (cellulose, starch, alginic acid), and synthetic polymers (vinyl, Others), synthetic polymers such as polyvinyl alcohol described below, and natural or semi-synthetic polymers made from plant-derived cellulose or the like correspond to water-soluble polymers that can be used in the present invention.
In the present invention, a water-soluble polymer may be labeled as a binder to distinguish it from the polymer latex.

Of the water-soluble polymers that can be used in the present invention, natural polymers and semi-synthetic polymers will be described in detail. Examples of plant polysaccharides include gum arabic, κ-carrageenan, ι-carrageenan, λ-carrageenan, guar gum (such as Supercol from Squalon), locust bean gum, pectin, tragacanth, and corn starch (Purity- from National Starch & Chemical Co.). 21), phosphorylated starch (National Star & Chemical Co., National 78-1898, etc.) and the like, and microbial polysaccharides such as xanthan gum (Kelco, Keltrol T), dextrin (National Star & Chemical Co., Ndex 360, etc.) ) And other animal-based natural polymers such as gelatin (Crodine B419 from Croda), casein Such as sodium chondroitin sulfate (such as Croda made Cromoist CS), and the like (all trade names). Cellulose-based materials include ethyl cellulose (ICF Cellofas WLD, etc.), carboxymethyl cellulose (Daicel CMC, etc.), hydroxyethyl cellulose (Daicel HEC, etc.), hydroxypropyl cellulose (Aqualon Klucel, etc.), and methyl cellulose (Henkel). Viscontran, etc.), nitrocellulose (Isopropyl Wet, etc. from Hercules), cationized cellulose (Crodacel QM, etc. from Croda), etc. (all are trade names). As starch systems, phosphorylated starch (such as National Star & Chemical National 78-1898), alginic acid systems such as sodium alginate (such as Kelco's Keltone), propylene glycol alginate, and other classifications include cationized guar gum (Alcolac). Hi-care 1000, etc.) and sodium hyaluronate (Hyalure, etc. from Lifecare Biomedical) (all are trade names).
In the present invention, gelatin is one of the preferred embodiments. The gelatin used in the present invention may have a molecular weight of 10,000 to 1,000,000. The gelatin used in the present invention may contain anions such as Cl ⁻ and SO ₄ ²⁻ , and may contain cations such as Fe ²⁺ , Ca ²⁺ , Mg ²⁺ , Sn ²⁺ and Zn ^2+. . It is preferable to add gelatin dissolved in water.

  Of the water-soluble polymers that can be used in the present invention, synthetic polymers will be described in detail. Examples of the acrylic system include sodium polyacrylate, polyacrylic acid copolymer, polyacrylamide, polyacrylamide copolymer, polydiethylaminoethyl (meth) acrylate quaternary salt or a copolymer thereof, and the vinyl system includes polyvinylpyrrolidone, Polyvinyl pyrrolidone copolymer, polyvinyl alcohol, etc. include polyethylene glycol, polypropylene glycol, polyisopropyl acrylamide, polymethyl vinyl ether, polyethylene imine, polystyrene sulfonic acid or copolymer thereof, naphthalene sulfonic acid condensate salt, polyvinyl sulfonic acid Or a copolymer thereof, polyacrylic acid or a copolymer thereof, acrylic acid or a copolymer thereof, a maleic acid copolymer, a maleic acid monoester copolymer, an acryloylme Propane sulfonic acid or its copolymer, etc.), polydimethyldiallylammonium chloride or its copolymer, polyamidine or its copolymer, polyimidazoline, dicyanciamide condensate, epichlorohydrin-dimethylamine condensate, polyacrylamide Hoffman Decomposition product, water-soluble polyester (Plus Coat Z-221, Z-446, Z-561, Z-450, Z-565, Z-850, Z-3308, RZ-105, RZ-570, manufactured by Kyodo Chemical Co., Ltd.) , Z-730, RZ-142 (both are trade names)).

Also, a highly water-absorbing polymer described in U.S. Pat. No. 4,960,681, JP-A-62-245260, that is, a vinyl monomer having —COOM or —SO3M (M is a hydrogen atom or an alkali metal). Homopolymers of these or copolymers of these vinyl monomers or other vinyl monomers (for example, sodium methacrylate, ammonium methacrylate, Sumikagel L-5H (trade name) manufactured by Sumitomo Chemical Co., Ltd.) can also be used. .

Of the water-soluble synthetic polymers that can be used in the present invention, polyvinyl alcohols are preferred.
Hereinafter, polyvinyl alcohol will be described in more detail.
As a complete saponified product, PVA-105 [polyvinyl alcohol (PVA) content 94.0% by mass or more, saponification degree 98.5 ± 0.5 mol%, sodium acetate content 1.5% by mass or less, volatile content 5 0.0 mass% or less, viscosity (4 mass%, 20 ° C.) 5.6 ± 0.4 CPS], PVA-110 [PVA content 94.0 mass%, saponification degree 98.5 ± 0.5 mol%, acetic acid Sodium content 1.5% by mass, volatile matter 5.0% by mass, viscosity (4% by mass, 20 ° C.) 11.0 ± 0.8 CPS], PVA-117 [PVA content 94.0% by mass, saponification degree 98.5 ± 0.5 mol%, sodium acetate content 1.0 mass%, volatile content 5.0 mass%, viscosity (4 mass%, 20 ° C.) 28.0 ± 3.0 CPS],

PVA-117H [PVA content 93.5% by mass, saponification degree 99.6 ± 0.3 mol%, sodium acetate content 1.85% by mass, volatile matter 5.0% by mass, viscosity (4% by mass, 20% ° C) 29.0 ± 3.0 CPS], PVA-120 [PVA content 94.0 mass%, saponification degree 98.5 ± 0.5 mol%, sodium acetate content 1.0 mass%, volatile content 5. 0 mass%, viscosity (4 mass%, 20 ° C.) 39.5 ± 4.5 CPS], PVA-124 [PVA content 94.0 mass%, saponification degree 98.5 ± 0.5 mol%, sodium acetate contained 1.0 mass%, volatile matter 5.0 mass%, viscosity (4 mass%, 20 ° C.) 60.0 ± 6.0 CPS],

PVA-124H [PVA content 93.5% by mass, saponification degree 99.6 ± 0.3 mol%, sodium acetate content 1.85% by mass, volatile matter 5.0% by mass, viscosity (4% by mass, 20% ° C) 61.0 ± 6.0 CPS], PVA-CS [PVA content 94.0% by mass, saponification degree 97.5 ± 0.5 mol%, sodium acetate content 1.0% by mass, volatile content 5. 0 mass%, viscosity (4 mass%, 20 ° C.) 27.5 ± 3.0 CPS], PVA-CST [PVA content 94.0 mass%, saponification degree 96.0 ± 0.5 mol%, sodium acetate contained 1.0 mass%, volatile matter 5.0 mass%, viscosity (4 mass%, 20 ° C.) 27.0 ± 3.0 CPS], PVA-HC [PVA content 90.0 mass%, saponification degree 99. 85 mol% or more, sodium acetate content 2.5 mass%, volatile content 8.5 mass%, viscosity (4 quality %, 20 ℃) 25.0 ± 3.5CPS] (or more, both of Kuraray Co., Ltd., trade name of) such as,

As a partially saponified product, PVA-203 [PVA content 94.0% by mass, saponification degree 88.0 ± 1.5 mol%, sodium acetate content 1.0% by mass, volatile matter 5.0% by mass, viscosity (4 mass%, 20 ° C.) 3.4 ± 0.2 CPS], PVA-204 [PVA content 94.0 mass%, saponification degree 88.0 ± 1.5 mol%, sodium acetate content 1.0 mass %, Volatile matter 5.0 mass%, viscosity (4 mass%, 20 ° C.) 3.9 ± 0.3 CPS], PVA-205 [PVA content 94.0 mass%, saponification degree 88.0 ± 1.5 Mol%, sodium acetate content 1.0% by mass, volatile matter 5.0% by mass, viscosity (4% by mass, 20 ° C.) 5.0 ± 0.4 CPS],

PVA-210 [PVA content 94.0% by mass, saponification degree 88.0 ± 1.0 mol%, sodium acetate content 1.0% by mass, volatile matter 5.0% by mass, viscosity (4% by mass, 20% ° C) 9.0 ± 1.0 CPS], PVA-217 [PVA content 94.0 mass%, saponification degree 88.0 ± 1.0 mol%, sodium acetate content 1.0 mass%, volatile content 5. 0 mass%, viscosity (4 mass%, 20 ° C.) 22.5 ± 2.0 CPS], PVA-220 [PVA content 94.0 mass%, saponification degree 88.0 ± 1.0 mol%, sodium acetate contained 1.0 mass%, volatile matter 5.0 mass%, viscosity (4 mass%, 20 ° C.) 30.0 ± 3.0 CPS],

PVA-224 [PVA content 94.0% by mass, saponification degree 88.0 ± 1.5 mol%, sodium acetate content 1.0% by mass, volatile matter 5.0% by mass, viscosity (4% by mass, 20% ° C) 44.0 ± 4.0 CPS], PVA-228 [PVA content 94.0 mass%, saponification degree 88.0 ± 1.5 mol%, sodium acetate content 1.0 mass%, volatile content 5. 0 mass%, viscosity (4 mass%, 20 ° C.) 65.0 ± 5.0 CPS], PVA-235 [PVA content 94.0 mass%, saponification degree 88.0 ± 1.5 mol%, sodium acetate contained 1.0 mass%, volatile matter 5.0 mass%, viscosity (4 mass%, 20 ° C.) 95.0 ± 15.0 CPS],

PVA-217EE [PVA content 94.0% by mass, saponification degree 88.0 ± 1.0 mol%, sodium acetate content 1.0% by mass, volatile matter 5.0% by mass, viscosity (4% by mass, 20% ° C) 23.0 ± 3.0 CPS], PVA-217E [PVA content 94.0% by mass, saponification degree 88.0 ± 1.0 mol%, sodium acetate content 1.0% by mass, volatile content 5. 0 mass%, viscosity (4 mass%, 20 ° C.) 23.0 ± 3.0 CPS], PVA-220E [PVA content 94.0 mass%, saponification degree 88.0 ± 1.0 mol%, sodium acetate contained 1.0 mass%, volatile matter 5.0 mass%, viscosity (4 mass%, 20 ° C.) 31.0 ± 4.0 CPS],

PVA-224E [PVA content 94.0% by mass, saponification degree 88.0 ± 1.0 mol%, sodium acetate content 1.0% by mass, volatile matter 5.0% by mass, viscosity (4% by mass, 20% ° C) 45.0 ± 5.0 CPS], PVA-403 [PVA content 94.0 mass%, saponification degree 80.0 ± 1.5 mol%, sodium acetate content 1.0 mass%, volatile content 5. 0 mass%, viscosity (4 mass%, 20 ° C.) 3.1 ± 0.3 CPS], PVA-405 [PVA content 94.0 mass%, saponification degree 81.5 ± 1.5 mol%, sodium acetate contained 1.0 mass%, volatile matter 5.0 mass%, viscosity (4 mass%, 20 ° C.) 4.8 ± 0.4 CPS],

PVA-420 [PVA content 94.0% by mass, saponification degree 79.5 ± 1.5 mol%, sodium acetate content 1.0% by mass, volatile matter 5.0% by mass], PVA-613 [PVA-containing Rate 94.0% by mass, degree of saponification 93.5 ± 1.0 mol%, sodium acetate content 1.0% by mass, volatile matter 5.0% by mass, viscosity (4% by mass, 20 ° C.) 16.5 ± 2.0 CPS], L-8 [PVA content 96.0 mass%, saponification degree 71.0 ± 1.5 mol%, sodium acetate content 1.0 mass% (ash content), volatile content 3.0 mass% , Viscosity (4% by mass, 20 ° C.), 5.4 ± 0.4 CPS] (all are trade names manufactured by Kuraray Co., Ltd.).

  In addition, said measured value is calculated | required according to JISK-6726-1977.

  As for the modified polyvinyl alcohol, those described in Koichi Nagano et al., “Poval” (published by Kobunshi Shuppankai) are used. There is modification by cation, anion, -SH compound, alkylthio compound, silanol.

  As such modified polyvinyl alcohol (modified PVA), C polymer as C-118, C-318, C-318-2A, C-506 (all are trade names manufactured by Kuraray Co., Ltd.), HL polymer HL-12E, HL-1203 (all are trade names made by Kuraray Co., Ltd.), HM polymer is HM-03, HM-N-03 (all are trade names made by Kuraray Co., Ltd.), KL-118, KL-318, KL-506, KM-118T, KM-618 (all are trade names manufactured by Kuraray Co., Ltd.) as the K polymer, and M-115 (manufactured by Kuraray Co., Ltd.) as the M polymer. (Trade name), MP-102, MP-202, MP-203 (all are trade names made by Kuraray Co., Ltd.) as MP polymers, and MPK-1, MPK- as MPK polymers. , MPK-3, MPK-4, MPK-5, MPK-6 (all are trade names manufactured by Kuraray Co., Ltd.), R-1130, R-2105, R-2130 (all are all as R polymers) Kuraray Co., Ltd. product name), V polymer V-2250 (Kuraray Co., Ltd. product name) and the like.

  Polyvinyl alcohol can be adjusted in viscosity or stabilized by a small amount of solvent or inorganic salt added to the aqueous solution. For details, refer to the above document, Koichi Nagano et al., “Poval”, Polymer Publications published by the publisher, pages 144 to 154 can be used. As a typical example, it is possible to improve the coating surface quality by containing boric acid, which is preferable. The addition amount of boric acid is preferably 0.01 to 40% by mass with respect to polyvinyl alcohol.

In the present invention, the water-soluble polymer is preferably polyvinyl alcohol or gelatin, and most preferably gelatin.
The addition amount of the water-soluble polymer in the receiving layer is preferably 1 to 25% by mass, and more preferably 1 to 10% by mass with respect to the entire receiving layer. Moreover, it is also one of the preferable aspects that a water-soluble polymer is not used.

  Polymers other than water-soluble polymers used as binders in the present invention can be easily obtained by solution polymerization, suspension polymerization, emulsion polymerization, dispersion polymerization, anionic polymerization, cationic polymerization, etc. The emulsion polymerization method obtained as is most preferable. Also preferred is a method of preparing a polymer in a solution and neutralizing or adding an emulsifier and then adding water and forcibly stirring to prepare an aqueous dispersion. In the emulsion polymerization method, for example, water or a mixed solvent of water and an organic solvent miscible with water (for example, methanol, ethanol, acetone, etc.) is used as a dispersion medium, and the monomer is 5 to 150% by mass with respect to the dispersion medium. Using the mixture and the total amount of monomers, an emulsifier and a polymerization initiator are used, and polymerization is carried out with stirring at about 30 to 100 ° C., preferably 60 to 90 ° C. for 3 to 24 hours. Various conditions such as the dispersion medium, the monomer concentration, the initiator amount, the emulsifier amount, the dispersant amount, the reaction temperature, and the monomer addition method are appropriately set in consideration of the type of monomer used. Moreover, it is preferable to use a dispersing agent as needed.

  The emulsion polymerization method can be generally performed according to the following literature. Tadashi Okuda, Hiroshi Inagaki, “Synthetic Resin Emulsion”, published by Polymer Press (1978), Takaaki Sugimura, Akio Kataoka, Junichi Suzuki, Keiji Kasahara, “Application of Synthetic Latex”, Published by Polymer Press (1993) 1), Soichi Muroi, “Chemistry of Synthetic Latex”, published by Kobunshi Shuppankai (1970). In the emulsion polymerization method for synthesizing the polymer latex used in the present invention, a batch polymerization method, a monomer (continuous / divided) addition method, an emulsion addition method, a seed polymerization method, etc. can be selected from the viewpoint of latex productivity. A batch polymerization method, a monomer (continuous / divided) addition method, and an emulsion addition method are preferred.

  The polymerization initiator only needs to have radical generating ability, and may be an inorganic peroxide such as persulfate or hydrogen peroxide, a peroxide described in “Oil peroxide catalog” of Nippon Oil & Fats, and Wako Jun. The azo compounds described in Yaku Kogyo Co., Ltd. “Azo Polymerization Initiator Catalog” can be used. Among them, water-soluble peroxides such as persulfate and water-soluble azo compounds described in Wako Pure Chemical Industries, Ltd. “Azo Polymerization Initiator Catalog” are preferable. Ammonium persulfate, sodium persulfate, potassium persulfate, Azobis (2-methylpropionamidine) hydrochloride, azobis (2-methyl-N- (2-hydroxyethyl) propionamide), azobiscyanovaleric acid is more preferable, and in particular, ammonium persulfate, sodium persulfate, potassium persulfate, etc. Peroxides are preferred from the viewpoints of image storability, solubility, and cost.

  As the addition amount of the polymerization initiator, the polymerization initiator is preferably 0.3% by mass to 2.0% by mass, and 0.4% by mass to 1.75% by mass with respect to the total amount of monomers. Is more preferable, and 0.5% by mass to 1.5% by mass is particularly preferable.

  As the polymerization emulsifier, any of an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant can be used, but the anionic surfactant has dispersibility and image storability. From the viewpoint, it is preferable to use a sulfonic acid type anionic surfactant because polymerization stability can be ensured in a small amount and resistance to hydrolysis, and a long chain represented by Perex SS-H (trade name, Kao Corporation). Alkyl diphenyl ether disulfonate is more preferable, and a low electrolyte type such as Pionein A-43-S (trade name, Takemoto Yushi Co., Ltd.) is particularly preferable.

  As the polymerization emulsifier, a sulfonic acid type anionic surfactant is preferably used in an amount of 0.1% by mass to 10.0% by mass with respect to the total amount of monomers, and 0.2% by mass to 7.5% by mass is used. It is more preferable that 0.3% by mass to 5.0% by mass is used.

  In the synthesis of the polymer latex used in the present invention, it is preferable to use a chelating agent. The chelating agent is a compound capable of coordinating (chelating) multivalent ions such as metal ions such as iron ions and alkaline earth metal ions such as calcium ions. Japanese Patent Publication No. 6-8956, US Pat. -73645, JP-A-4-127145, JP-A-4-247703, JP-A-4-305572, JP-A-6-11805, JP-A-5-1773312, JP-A-5-66527, JP-A-5-67527. 158195, JP-A-6-118580, JP-A-6-110168, JP-A-6-161054, JP-A-6-175299, JP-A-6-214352, JP-A-7-114161, JP-A-7-114154 JP-A-7-120894, JP-A-7-199433, JP-A-7-306504, JP-A-9-43792 , JP-A-8-314090, JP-A-10-182571, JP-A-10-182570, can be employed compounds described in JP-A-11-190892.

  Examples of the chelating agent include inorganic chelate compounds (sodium tripolyphosphate, sodium hexametaphosphate, sodium tetrapolyphosphate, etc.), aminopolycarboxylic acid chelate compounds (nitrilotritriacetic acid, ethylenediaminetetraacetic acid, etc.), organic phosphonic acid chelate compounds ( Research Disclosure 18170, JP-A-52-102726, 53-42730, 56-97347, 54-121127, 55-4024, 55-4025, 55-29883, 55 -126241, 55-65955, 55-65956, 57-17943, 54-61125, and West German Patent No. 1045373), polyphenol-based chelating agents, polyamine-based chelates Preferably such DOO compounds, with aminopolycarboxylic acid derivatives being particularly preferred.

  Preferable examples of the aminopolycarboxylic acid derivatives include the compounds listed in the appendix of “EDTA (-Complexane Chemistry)” (Nanedo, 1977), and some of the carboxyl groups of these compounds are sodium or potassium. Alkali metal salts and ammonium salts such as may be substituted. Particularly preferred aminocarboxylic acid derivatives include iminodiacetic acid, N-methyliminodiacetic acid, N- (2-aminoethyl) iminodiacetic acid, N- (carbamoylmethyl) iminodiacetic acid, nitrilotriacetic acid, ethylenediamine-N, N '-Diacetic acid, ethylenediamine-N, N'-di-α-propionic acid, ethylenediamine-N, N'-di-β-propionic acid, N, N'-ethylene-bis (α-o-hydroxyphenyl) glycine N, N′-di (2-hydroxybenzyl) ethylenediamine-N, N′-diacetic acid, ethylenediamine-N, N′-diacetic acid-N, N′-diacethydroxamic acid, N-hydroxyethylethylenediamine-N , N ′, N′-triacetic acid, ethylenediamine-N, N, N ′, N′-tetraacetic acid, 1,2-propylenediamine-N, N, N ′ N′-tetraacetic acid, d, l-2,3-diaminobutane-N, N, N ′, N′-tetraacetic acid, meso-2,3-diaminobutane-N, N, N ′, N′-four Acetic acid, 1-phenylethylenediamine-N, N, N ′, N′-tetraacetic acid, d, l-1,2-diphenylethylenediamine-N, N, N ′, N′-tetraacetic acid, 1,4-diaminobutane -N, N, N ', N'-tetraacetic acid, trans-cyclobutane-1,2-diamine-N, N, N', N'-tetraacetic acid, trans-cyclopentane-1,2-diamine-N, N, N ′, N′-tetraacetic acid, trans-cyclohexane-1,2-diamine-N, N, N ′, N′-tetraacetic acid, cis-cyclohexane-1,2-diamine-N, N, N ′ , N′-tetraacetic acid, cyclohexane-1,3-diamine-N, N, N ′, N′-four Acid, cyclohexane-1,4-diamine-N, N, N ′, N′-tetraacetic acid, o-phenylenediamine-N, N, N ′, N′-tetraacetic acid, cis-1,4-diaminobutene- N, N, N ′, N′-tetraacetic acid, trans-1,4-diaminobutene-N, N, N ′, N′-tetraacetic acid, α, α′-diamino-o-xylene-N, N, N ′, N′-tetraacetic acid, 2-hydroxy-1,3-propanediamine-N, N, N ′, N′-tetraacetic acid, 2,2′-oxy-bis (ethyliminodiacetic acid), 2,2 '-Ethylenedioxy-bis (ethyliminodiacetic acid), ethylenediamine-N, N'-diacetic acid-N, N'-di-α-propionic acid, ethylenediamine-N, N'-diacetic acid-N, N'- Di-β-propionic acid, ethylenediamine-N, N, N ′, N′-tetrapropionic acid Diethylenetriamine-N, N, N ′, N ″, N ″ -pentaacetic acid, triethylenetetramine-N, N, N ′, N ″, N ′ ″, N ′ ″-hexaacetic acid, 1, 2,3-triaminopropane-N, N, N ′, N ″, N ′ ″, N ′ ″-hexaacetic acid, and some of the carboxyl groups of these compounds include sodium and potassium. Substituted ones such as alkali metal salts and ammonium salts can also be mentioned.

  The addition amount of the chelating agent is preferably 0.01% by mass to 0.4% by mass, more preferably 0.02% by mass to 0.3% by mass with respect to the total amount of monomers. It is especially preferable that it is 03 mass%-0.15 mass%. When the amount of the chelating agent is less than 0.01% by mass, capture of metal ions mixed in the production process of the polymer latex becomes insufficient, stability against aggregation of the latex is lowered, and applicability is deteriorated. On the other hand, if it exceeds 0.4%, the viscosity of the latex increases and the coatability is lowered.

  A chain transfer agent is preferably used for the synthesis of the polymer latex used in the present invention. As the chain transfer agent, those described in “Polymer Handbook, 3rd edition” (Wiley-Interscience, 1989) are preferable. Sulfur compounds are more preferred because they have high chain transfer ability and can be used in small amounts. Hydrophobic mercaptan-based chain transfer agents such as tert-dodecyl mercaptan and n-dodecyl mercaptan are particularly preferred.

  The amount of the chain transfer agent is preferably 0.2% by mass to 2.0% by mass, more preferably 0.3% by mass to 1.8% by mass, and 0.4% by mass to 1.6% by mass with respect to the total amount of monomers. Mass% is particularly preferred.

  In emulsion polymerization, in addition to the above compounds, electrolytes, stabilizers, thickeners, antifoaming agents, antioxidants, vulcanizing agents, antifreezing agents, gelling agents, vulcanization accelerators, etc. are described in synthetic rubber handbooks, etc. These additives may be used.

  In the polymer latex used in the present invention, an aqueous solvent can be used as a solvent in the coating solution, but a water-miscible organic solvent may be used in combination. Examples of the water-miscible organic solvent include alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol, cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve, ethyl acetate and dimethylformamide. The amount of these organic solvents added is preferably 40% or less, more preferably 30% or less of the solvent.

The polymer latex used in the present invention preferably has a polymer concentration of 10 to 70% by mass, more preferably 20 to 60% by mass, and particularly preferably 30 to 55% by mass with respect to the latex liquid.
The addition amount of the polymer latex is preferably 50 to 95% by mass, more preferably 70 to 90% by mass, based on the total polymer content in the receptor layer.
In addition, the polymer latex in the image-receiving sheet of the present invention includes a gel or dry film state formed by drying a part of the solvent after coating.

<Organic solvent>
The organic solvent used in the present invention will be described.
In the present invention, an organic solvent having a boiling point of 140 to 220 ° C. is used for the coating solution of the constituent layer coated on the receiving layer side on the support. Preferably, the function of forming a polymer latex that accepts the above-mentioned dye functions as a result. The organic solvent may be added to any of the coating liquids of the constituent layers coated on the receiving layer side on the support, but is preferably present at least in the receiving layer. Yes, it is a coating solution for coating the receiving layer.
The organic solvent used in the present invention acts effectively to achieve the effects of the present invention, but a part of this action is the action of forming a polymer latex in the receiving layer (mainly coating and drying). The film formation is advanced in the process) and is not the function of the conventional film forming aid alone.
Examples of the organic solvent that can be added to the coating solution for producing the thermal transfer image-receiving sheet include ethyl acetoacetate, tetramethylsulfone, γ-butyllactone, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether, diacetone alcohol, diglyme, Dimethyl sulfoxide, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol diethyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol-n-butyl acetate, cyclohexanone, cyclopentanone, lactic acid Ethyl, methyl lactate, butyl acetate, acetic acid Chlohexyl, 2-heptanone, ethyl pyruvate, 3,5,5-trimethyl-2-cyclohexen-1-one, butyl lactate, propylene glycol, propylene glycol diacetate, propylene glycol-n-propyl ether acetate, propylene glycol phenyl ether Acetate, propylene glycol monomethyl ether acetate, 2-ethylhexyl acetate, 3-methoxy-3-methylbutyl acetate, tripropylene glycol methyl ethyl acetate, 1-methoxypropyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, tetrahydrofuryl alcohol, ethoxypropyl propionate and the like can be mentioned.

In the present invention, the organic solvent includes a plasticizer in the case where the polymer latex to be used contains a plasticizer, an auxiliary for adding the polymer latex, and a dispersion auxiliary used in the emulsified dispersion described later. Also included are those used as a solvent for forming the heat insulating layer, but as described above, it is preferably added to the coating solution for the receiving layer, more preferably added as a solvent.
The organic solvent of the present invention has a boiling point of 140 to 220 ° C., and when an organic solvent having a boiling point of 140 ° C. or lower is used, the strength of the receiving layer cannot be made uniform, and scratch-like failure occurs in the output image. The effect of preventing the occurrence is small. In the case of an organic solvent having a boiling point of 140 ° C. or higher, the above-mentioned failure prevention effect is further increased. When an organic solvent having a boiling point of 220 ° C. is used, the strength of the receiving layer can be made uniform and failure can be prevented, but bleeding of the printed image occurs and the image quality deteriorates.
The boiling point of the organic solvent is preferably 150 to 220 ° C, more preferably 170 to 220 ° C, and further preferably 180 to 220 ° C.
In particular, in the present invention, when compared with an organic solvent used merely as a film-forming aid, many of these organic solvents have insufficient film-forming action or films after producing a thermal transfer image-receiving sheet. Disadvantages that cause adverse effects (deterioration of color bleeding, etc.) due to remaining in the resin are eliminated, and at the same time, the effect of the present invention is effectively exerted.
The organic solvent of the present invention is preferably a water-soluble organic solvent, preferably 50 g or more dissolved in 100 ml of water, that is, a solvent that is mixed without separating layers, and preferably 100 g or more. On the other hand, the composition of the organic solvent preferably has 4 or more (preferably 12 or less) carbon atoms, more preferably 5 or more (preferably 10 or less). Further, the organic solvent is preferably composed of carbon atoms, hydrogen atoms and oxygen atoms or / and sulfur atoms, more preferably composed of carbon atoms, hydrogen atoms and oxygen atoms. is there. The organic solvent is preferably neutral, not acidic or alkaline. When viewed from the functional group constituting the organic solvent, it has at least a hydroxyl group and / or an alkyleneoxy group (preferably —CH ₂ 0—, —CH ₂ CH ₂ O—).

Examples of such organic solvents include alcohol solvents, ethylene glycol solvents, propylene glycol solvents, and diethylene glycol solvents, and those in which these hydroxyl groups are etherified and esterified can be mentioned.
For example, ethylene glycol (197.2 ° C), propylene glycol (187.3 ° C), butyl cellosolve (171.2 ° C), methyl cellosolve acetate (144.5 ° C), cellosolve acetate (156.3 ° C), methylcarb Thor (193.2 ° C.), carbitol (201.9 ° C.), diethyl carbitol (186.0 ° C.), carbitol acetate (218.0 ° C.), diacetone alcohol (168.0 ° C.).

These organic solvents may be disadvantageous in terms of dispersion stability of the polymer latex in the state of the coating liquid containing the polymer latex in the property of promoting the film formation of the latex to be used. It is necessary to select an appropriate one.
Moreover, in order to improve the dispersion stability of the polymer latex in the coating solution, a method of mixing the organic solvent used in the present invention with the coating solution immediately before coating in the course of coating and feeding can be suitably used.
The addition amount of the organic solvent of the present invention is preferably 1% or more and 100% or less, more preferably 3% or more and 80% or less, and still more preferably with respect to the solid content of the latex polymer of the receiving layer. It is 10% or more and 60% or less. In addition, also when adding to another layer, it is preferable to add by mass ratio with the solid content of the said polymer latex in a receiving layer.
The organic solvent of the present invention is preferably one that volatilizes during the coating, drying process or storage, and is supported with the heat-sensitive image receiving sheet either immediately after the production of the heat-sensitive transfer image-receiving sheet or between the production and the image formation. It is 3% or less (preferably 1% or less) with respect to the total coating solid content in all the constituent layers on the receiving layer side on the body. If it remains 3% or more, blurring of the printed image occurs, resulting in a problem in that the image quality deteriorates. In order to make such a residual amount, in addition to the conditions in the drying process and the drying process that is normally performed, heat treatment for this purpose may be performed, but the drying process that is normally performed It is preferable to achieve this.
Moreover, the aspect which is 0.001%-3% of the content of said organic solvent in this invention and a residual amount, and the aspect which is 0 to less than 0.001% (mode which does not contain substantially) are preferable.

<Ultraviolet absorber>
In the present invention, an ultraviolet absorber may be added to the receiving layer in order to improve light resistance. At this time, the UV absorber can be fixed to the receiving layer by increasing the molecular weight, and can be prevented from being diffused into the ink sheet or sublimation / transpiration due to heating.
As the ultraviolet absorber, compounds having various ultraviolet absorber skeletons widely known in the field of information recording can be used. Specific examples include 2-hydroxybenzotriazole type ultraviolet absorbers, 2-hydroxybenzotriazine type ultraviolet absorbers, and compounds having a 2-hydroxybenzophenone type ultraviolet absorber skeleton. A compound having a benzotriazole type or triazine skeleton is preferable from the viewpoint of ultraviolet absorption ability (absorption coefficient) / stability, and a compound having a benzotriazole type or benzophenone type skeleton is preferable from the viewpoint of increasing the molecular weight or forming a latex. Specifically, an ultraviolet absorber described in JP 2004-361936 A can be used.

  The ultraviolet absorber preferably has absorption in the ultraviolet region and does not have an absorption edge in the visible region. Specifically, when added to the receiving layer to form a thermal transfer image-receiving sheet, the reflection density at 370 nm is preferably Abs 0.5 or more, and the reflection density at 380 nm is more preferably Abs 0.5 or more. . The reflection density at 400 nm is preferably Abs 0.1 or less. A high reflection density in the range exceeding 400 nm is not preferable because the image is yellowed.

  In the present invention, the ultraviolet absorber has a high molecular weight and preferably has a mass average molecular weight of 10,000 or more, more preferably a mass average molecular weight of 100,000 or more. As a means for increasing the molecular weight, it is preferable to graft an ultraviolet absorber onto the polymer. The polymer that becomes the main chain preferably has a polymer skeleton that is inferior in dyeability to the dye used in combination. Moreover, it is preferable to have sufficient film strength when the film is formed. The graft ratio of the ultraviolet absorber to the polymer main chain is preferably 5 to 20% by mass, and more preferably 8 to 15% by mass.

Moreover, it is more preferable that the polymer grafted with the ultraviolet absorber is made into a latex. The receptor layer can be formed by forming an aqueous dispersion type coating solution into a latex to form a latex, and the manufacturing cost can be reduced. For example, the method described in Japanese Patent No. 3450339 can be used as a method for forming a latex. Examples of the latex-made ultraviolet absorber include ULS-700, ULS-1700, ULS-1383MA, ULS-1635MH, XL-7016, ULS-933LP, ULS-935LH, Shin-Nakamura Chemical Co., Ltd. Commercially available ultraviolet absorbers such as New Coat UVA-1025W, New Coat UVA-204W, and New Coat UVA-4512M (both are trade names) can also be used.
When the polymer to which the ultraviolet absorber is grafted is made into a latex, it is possible to form a receiving layer in which the ultraviolet absorber is uniformly dispersed by mixing with the latex of the above-mentioned dyeable receiving polymer and applying it.

  The added amount of the polymer grafted with the ultraviolet absorber or the latex thereof is preferably 5 to 50 parts by mass, more preferably 10 to 30 parts by mass with respect to the dyeable accepting polymer latex forming the receptor layer.

<Release agent>
In addition, a release agent may be added to the receiving layer in order to prevent thermal fusion with the thermal transfer sheet during image formation. As the release agent, silicone oil and phosphoric ester plasticizer fluorine compound can be used, and silicone oil is particularly preferably used. As the silicone oil, modified silicone oils such as epoxy modification, alkyl modification, amino modification, carboxyl modification, alcohol modification, fluorine modification, alkylaralkyl polyether modification, epoxy / polyether modification, and polyether modification are preferably used. The reaction product of vinyl modified silicone oil and hydrogen modified silicone oil is good. The addition amount of the release agent is preferably 0.2 to 30 parts by mass with respect to the receiving polymer.
The lubricant described in the emulsion section below is almost synonymous with the same effect as the release agent described here. In this invention, what was used as a dispersion for convenience was made into the mold release agent demonstrated here as a lubricant emulsion and the other thing.

<Emulsions>
Hydrophobic additives such as lubricants and antioxidants can be obtained by a known method such as the method described in US Pat. No. 2,322,027, such as a layer of an image receiving sheet (for example, a receiving layer, a heat insulating layer, an undercoat layer, etc.). ) Can be introduced in. In this case, U.S. Pat. Nos. 4,555,470, 4,536,466, 4,536,467, 4,587,206, 4,555,476 No. 4,599,296, JP-B-3-62256, or a high boiling point organic solvent described in the specification or the like, if necessary, in combination with a low boiling point organic solvent having a boiling point of 50 ° C. to 160 ° C. Can be used. These lubricants, antioxidants, high-boiling organic solvents and the like can be used in combination of two or more.
Examples of the lubricant include solid waxes such as polyethylene wax, amide wax, and Teflon (registered trademark) powder; silicone oil, phosphate ester compounds, fluorine surfactants, silicone surfactants, and other in the technical field. A known release agent can be used. Silicone compounds such as various waxes, fluorine compounds represented by fluorine surfactants, silicone surfactants, silicone oils and / or cured products thereof are preferably used.

<Matting agent>
In the present invention, it is preferable to add a matting agent for imparting releasability. The matting agent is preferably contained in the outermost surface layer, the layer functioning as the outermost surface layer of the heat-sensitive transfer image-receiving sheet, or a layer close to the outer surface. The outermost surface layer can be made into two layers as required. Most preferably, it is added to the outermost receiving layer. The matting agent can be added to both the outermost layer on the image forming layer surface and the outermost layer on the back surface, and can also be added to both layers. In particular, it is preferable to include a matting agent on the side of the support containing the slip agent.

  The matting agent is preferably dispersed in advance with a binder and used as a matting agent particle dispersion.

  Examples of the matting agent generally include fine particles of an organic compound insoluble in water and fine particles of an inorganic compound. In the present invention, fine particles containing an organic compound are preferable from the viewpoint of dispersibility. As long as it contains an organic compound, it may be an organic compound fine particle composed of an organic compound alone, or an organic / inorganic composite fine particle containing not only an organic compound but also an inorganic compound. Examples of the matting agent include, for example, U.S. Pat. Nos. 1,939,213, 2,701,245, 2,322,037, 3,262,782, 3,539,344, Those well known in the silver salt sensitive material industry such as the organic matting agent described in each specification such as US Pat. No. 3,767,448 can be used.

Since the temperature of the receiving layer surface becomes high during image printing, the matting agent preferably has heat resistance.
In particular, a polymer having a thermal decomposition temperature of 200 ° C. or higher is preferable. More preferably, it is a polymer having a thermal decomposition temperature of 240 ° C. or higher.
In addition, when the image is printed, not only heat but also pressure is applied to the surface of the receiving layer.

  The matting agent contained in the outermost layer on the image forming layer side and the outermost layer adjacent layer is dispersed in advance with a binder and used as a matting agent particle dispersion. The dispersion method is (a) a matting agent. The dispersion of the matting agent by removing the low boiling point organic solvent from the emulsion by emulsifying and dispersing the polymer to be dissolved in an aqueous medium as a solution (for example, dissolved in a low boiling point organic solvent) to obtain polymer droplets There are two methods: (b) a method in which fine particles such as a polymer to be a matting agent are prepared in advance, and a dispersion is prepared so as not to cause lumps in an aqueous medium. In the present invention, in consideration of the environment, the method (b) in which a low-boiling organic solvent is not discharged to the environment is preferable.

  Since the dispersion state of the mat particle dispersion in the present invention is stabilized when it contains a surfactant, it is preferable to add a surfactant.

<Surfactant>
In the heat-sensitive transfer image-receiving sheet of the present invention, a surfactant can be contained in the above arbitrary layer. Among these, it is preferable to make it contain in a receiving layer and an intermediate | middle layer.
The addition amount of the surfactant is preferably 0.01 to 5% by mass, more preferably 0.01 to 1% by mass, and 0.02 to 0.2% by mass with respect to the total solid content. It is particularly preferred that
Various surfactants such as anionic, nonionic, and cationic surfactants are known. As the surfactant that can be used in the present invention, known ones can be used. For example, those introduced in “Supervision of Functional Surfactant / Mitsuo Tsunoda, Issued / August 2000, Chapter 6” Among them, an anionic fluorine-containing surfactant is preferable.
Application is possible even when no surfactant is contained, but since the surface tension of the application liquid is high, the application surface may be uneven and uneven. By containing a surfactant in the coating solution, the surface tension can be lowered, unevenness during coating can be eliminated, the coated surface can be made uniform, and coating can be performed stably.

  Although the specific example of a fluorine compound is illustrated below, the fluorine compound which can be used by this invention is not restrict | limited at all by the following specific examples. Unless otherwise specified, the alkyl group and perfluoroalkyl group in the structure notation of the following exemplified compounds means a group having a linear structure.

  These fluorine compounds are used as a surfactant in a coating composition for forming a layer constituting a heat-sensitive transfer image-receiving sheet (in particular, a receiving layer, a heat insulating layer, a protective layer, an undercoat layer, a back layer, etc.). However, in the present invention, it can be preferably contained in the receiving layer and the intermediate layer.

<Preservative>
If the coating solution, the image receiving sheet, the print image, and the like are stored, microorganisms (particularly bacteria, mold, yeast, etc.) adhere to these materials during storage, and their performance is often lowered. In order to prevent this, a preservative can be contained in a range that does not affect other performances.
The preservative referred to in the present invention is a compound used to suppress the compound used in the image-receiving sheet from undergoing a decomposition reaction due to the growth of the microorganism, and the definition and specific compound by the general formula are Handbook, Gihodo Publishing (1986), Hiroshi Horiguchi, Antibacterial and Funeral Chemistry, Sankyo Publishing (1986), Antibacterial and Antifungal Encyclopedia, Japanese Antibacterial and Antifungal Society (1986).
The preservative contained in the image-receiving sheet of the present invention is not particularly limited, but phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzoisothiazoline-3-one, benzo Triazole derivatives, amiding anidine derivatives, quaternary ammonium salts, derivatives such as pyrrolidine, quinoline, guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, 2-mercaptopyridine-N-oxide or salts thereof, formaldehyde donor antibacterial agents, etc. Can be mentioned. Among these, phenol or a derivative thereof, 4-isothiazolin-3-one derivative, benzisothiazolin-3-one, and the like are preferable.

  In addition to these, compounds represented by any one of the following general formulas [I] to [IV] can be used as preservatives.

In general formula [I], R ₁ and R ₂ may be the same or different and each represents a hydrogen atom, a hydroxy group, or a lower alkyl group. X is a hydrogen atom, a halogen atom, a nitro group, a cyano group, an aryl group, a lower alkyl group, a lower alkenyl group, an aralkyl group, an alkoxy group, —COR ₃ , —SO ₂ R ₄ , or —N (R ₅ ) R _6. R ₃ and R ₄ represent a hydrogen atom, —OM, a lower alkyl group, a lower alkoxy group, or —N (R ₇ ) R ₈ .
R ₅ and R ₆ may be the same or different and each represents a hydrogen atom, a lower alkyl group, —COR ₉ , or —SO ₂ R ₁₀ . R ₉ and R ₁₀ represent a lower alkyl group or —N (R ₁₁ ) R ₁₂ , and R ₇ , R ₈ , R ₁₁ , and R ₁₂ may be the same or different, and may be a hydrogen atom or a lower alkyl group. Represents.
M represents a hydrogen atom, an alkali metal atom, or an atomic group necessary to form a monovalent cation, l represents an integer of 2 to 6, m represents an integer of 1 to 4, and n represents 6- represents an integer of m. However, when there are a plurality of R ₁ , R ₂ , and X, each may be different from each other.

一般式〔ＩＩ〕中、Ｒ_１３は水素原子、アルキル基、アルケニル基、アラルキル基、アリール基、複素環基、

In the general formula [II], R ₁₃ represents a hydrogen atom, an alkyl group, an alkenyl group, an aralkyl group, an aryl group, a heterocyclic group,

を表し、Ｒ_１４、Ｒ_１５は各々水素原子、アルキル基、アリール基、シアノ基、複素環基、アルキルチオ基、アルキルスルホキシ基、アルキルスルホニル基を表し、Ｒ_１４とＲ_１５は互いに結合して芳香環を形成していても良い。Ｒ_１６、Ｒ_１７は各々水素原子、アルキル基、アリール基、アラルキル基を表す。

R ₁₄ and R ₁₅ each represent a hydrogen atom, an alkyl group, an aryl group, a cyano group, a heterocyclic group, an alkylthio group, an alkylsulfoxy group, or an alkylsulfonyl group, and R ₁₄ and R ₁₅ are bonded to each other. An aromatic ring may be formed. R ₁₆ and R ₁₇ each represent a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group.

Among these, those in which R ₁₄ and R ₁₅ are hydrogen atoms and R ₁₃ is a methyl group (hereinafter referred to as compound II-a) are preferable. In addition, R ₁₄ and R ₁₅ are bonded to each other to form an aromatic ring and R ₁₃ is a hydrogen atom in combination with Compound II-a, and R ₁₄ is a chlorine atom, R ₁₅ is a hydrogen atom, R ₁₃ The combination of the compound in which is a methyl group and compound II-a is further preferred.

In the general formula [III], R ₁₈ represents a hydrogen atom, an alkyl group or a hydroxymethyl group;
₁₉ represents a hydrogen atom or an alkyl group.

In the general formula [IV], R ₂₀ represents a lower alkylene group, X represents a hydrogen atom, a halogen atom, a nitro group, a hydroxy group, a cyano group, a lower alkyl group, a lower alkoxy group, —COR ₂₁ , —N (R ₂₂ ) represents R ₂₃ , —SO ₃ M, R ₂₁ represents a hydrogen atom, —OM, lower alkyl group, aryl group, aralkyl group, lower alkoxy group, aryloxy group, aralkyloxy group, —N (R ₂₄ ) R ₂₅ .
R ₂₂ and R ₂₃ each represents a hydrogen atom, a lower alkyl group, an aryl group, an aralkyl group, —COR ₂₆ , —SO ₂ R _{26, and} may be the same or different from each other, and R ₂₄ , R ₂₅ Each represents a hydrogen atom, a lower alkyl group, an aryl group or an aralkyl group, and may be the same or different from each other, R ₂₆ represents a lower alkyl group, an aryl group or an aralkyl group, M represents a hydrogen atom, An atomic group necessary for forming an alkali metal atom and a monovalent cation is represented, p represents 0 or 1, and q represents 0 or an integer from 1 to 5.

  Any one of the preservatives may be used alone, or two or more arbitrary compounds may be selected and used in combination. The preservative may be added as it is, but it may be dissolved in water or an organic solvent such as methanol, ethanol, isopropyl alcohol, acetone, ethylene, or ethylene glycol, and added as a solution to the image-receiving sheet coating solution. Or you may add in latex. Alternatively, it may be dissolved in a high boiling point solvent, a low boiling point solvent, or a mixed solvent of both, and then emulsified and dispersed in the presence of a surfactant and added to the latex.

The coating amount of the receiving layer is preferably 0.5 to 10 g / m ² (in terms of solid content, hereinafter the coating amount in the present invention is a numerical value in terms of solid content unless otherwise specified). The thickness of the receiving layer is preferably 1 to 20 μm.

(Insulation layer)
The heat insulating layer (porous layer) serves to protect the support from heat during heat transfer using a thermal head. Moreover, since it has high cushioning properties, a thermal transfer image-receiving sheet with high printing sensitivity can be obtained even when paper is used as the support.

In the image receiving sheet of the present invention, the heat insulating layer contains a hollow polymer.
The hollow polymer in the present invention is a polymer particle having independent pores inside the particle, preferably a polymer latex. For example, 1) water is contained in a partition wall formed of polystyrene, acrylic resin, styrene-acrylic resin, or the like. Non-foamed hollow polymer particles in which the water inside the particles evaporates outside the particles after coating and drying, and the inside of the particles becomes hollow. 2) Low-boiling liquids such as butane and pentane are added to polyvinylidene chloride, poly It is covered with a resin made of acrylonitrile, polyacrylic acid, polyacrylic acid ester, or a mixture or polymer thereof. After coating, the low-boiling liquid inside the particles expands by heating, and the interior becomes hollow. Foaming type microballoons 3) Microvalves obtained by heating and foaming the above 2) in advance to form a hollow polymer Such as emissions, and the like.

These hollow polymers preferably have an average particle size of 0.1 to 5.0 μm, more preferably 0.2 to 3.0 μm, and particularly preferably 0.3 to 1.0 μm. If this size is too small, the hollowness tends to decrease and the desired heat insulating property cannot be obtained. If the size is too large, the frequency of occurrence of planar failures other than coarse particles in the heat insulating layer increases.
The hollow polymer preferably has a hollow ratio of about 20 to 70%, particularly preferably 20 to 50%. If the hollow ratio is too small, the desired heat insulating property cannot be obtained, and if it is too large, the ratio of hollow polymer particles and incomplete hollow particles that are easily broken increases, resulting in printing defects and insufficient film strength. .
Two or more types of hollow polymers can be mixed and used as necessary. Specific examples of 1) include Low and Haas Ropaque 1055, Dainippon Ink Boncoat PP-1000, JSR SX866 (B), Nippon Zeon Nipol MH5055 (all trade names), and the like. . Specific examples of 2) include F-30 and F-50 (both trade names) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. Specific examples of 3) include F-30E manufactured by Matsumoto Yushi Seiyaku Co., Ltd., EXPANSEL 461DE, 551DE, and 551DE20 (all trade names) manufactured by Nippon Ferrite Co., Ltd. The hollow polymer used for the heat insulating layer may be made into a latex.

A hollow polymer that is 10 ° C. or more higher than the glass transition temperature of the latex polymer is preferred. When the glass transition temperature is low, hollow polymer particles having a sufficient porosity cannot be obtained after the coating / drying step. More specifically, a hollow polymer having a glass transition temperature of 90 ° C. or higher is more preferable. As the hollow polymer used in the present invention, non-foamed hollow polymer particles are preferable. Those preferably 200 ° C. or less are particularly preferred.
Here, the relationship between the glass transition temperatures of at least one hollow polymer (glass transition temperature Tg2) and the polymer latex (Tg1) for receiving at least one dye in the receiving layer is Tg1 + 10 ≦ Tg2. The case where there is a relationship is preferable in terms of the effect of the present invention.

  The heat insulating layer containing the hollow polymer preferably contains a water-dispersed resin or a water-soluble resin as a binder in addition to the hollow polymer. Examples of the binder resin used in the present invention include acrylic resins, styrene-acrylic copolymers, polystyrene resins, polyvinyl alcohol resins, vinyl acetate resins, ethylene-vinyl acetate copolymers, vinyl chloride vinyl acetate copolymers, and styrene. Known resins such as a butadiene copolymer, a urethane resin, a polyvinylidene chloride resin, a cellulose derivative, casein, starch, and gelatin can be used. These are preferably water-soluble polymers described in the receiving layer. Among these binder resins, gelatin, polyvinyl alcohol, styrene-butadiene copolymer and urethane resin are preferable, and gelatin and polyvinyl alcohol are more preferable. These resins can be used alone or in combination.

Moreover, it is preferable that a heat insulation layer contains the said water-soluble polymer. The water-soluble polymer may be dissolved in an amount of 0.05 g or more with respect to 100 g of water at 20 ° C., more preferably 0.1 g or more, still more preferably 0.5 g or more, and particularly preferably 1 g or more. The polymer latex is obtained by dispersing polymer fine particles in a dispersion medium, and is different from the water-soluble polymer of the present invention. Examples of water-soluble polymers that can be preferably used include gelatin and polyvinyl alcohol. Of these, gelatin is particularly preferable. The gelatin used in the present invention may have a molecular weight of 10,000 to 1,000,000. The gelatin used in the present invention may contain anions such as Cl ⁻ and SO ₄ ²⁻ , and may contain cations such as Fe ²⁺ , Ca ²⁺ , Mg ²⁺ , Sn ²⁺ and Zn ^2+. . It is preferable to add gelatin dissolved in water.
The amount of the water-soluble polymer added to the heat insulating layer is preferably 1 to 75% by mass and more preferably 1 to 50% by mass with respect to the entire heat insulating layer.

Moreover, it is preferable that the water-soluble polymer contained in the heat insulation layer is crosslinked by a crosslinking agent. The preferred range of the crosslinking agent that can be preferably used and the amount of use thereof is the same as described above.
Although the water-soluble polymer in the heat insulating layer varies depending on the type of the crosslinking agent, it is preferably 0.1 to 20% by mass crosslinked with respect to the water-soluble polymer, and 1 to 10% by mass crosslinked. Is more preferable.

  The solid content of the hollow polymer in the heat insulating layer is preferably between 5 and 2000 parts by mass when the solids content of the binder resin is 100 parts by mass. Moreover, 1-70 mass% is preferable, and, as for the mass ratio which occupies with respect to the coating liquid of the solid content of a hollow polymer, 10-40 mass% is more preferable. If the ratio of the hollow polymer is too small, sufficient heat insulation cannot be obtained, and if the ratio of the hollow polymer is too large, the binding force between the hollow polymers decreases, causing problems such as powder falling off during processing or film peeling. Arise.

0.5-14 mass% is preferable, and, as for the quantity which occupies for the coating liquid of the said binder of a heat insulation layer, 1-6 mass% is especially preferable. The coating amount of the hollow polymer in the heat insulation layer is preferably ^{1~100g / m 2, 5~20g / m} 2 is more preferable.
The thickness of the heat insulating layer containing the hollow polymer is preferably 5 to 50 μm, and more preferably 5 to 40 μm.

The porosity of the heat insulating layer calculated from the thickness of the heat insulating layer containing the hollow polymer and the solid coating amount of the heat insulating layer containing the hollow polymer is preferably 10 to 70%, and more preferably 15 to 60%. When the porosity of the heat insulating layer is less than 10%, sufficient heat insulating properties cannot be obtained, and when it is 70% or more, the binding force between the hollow polymers is lowered, and sufficient film strength cannot be obtained, and the scratch resistance is deteriorated.
In the present invention, the porosity of the heat insulating layer is a value V calculated by the following equation (b).

      V = 1−L / L × Σgi · di (Formula b)

  In the above formula (b), L represents the film thickness of the heat insulating layer, gi represents the solid coating amount of the specific material i constituting the heat insulating layer, and di represents the specific gravity of the specific material i. Here, when di represents the specific gravity of the hollow polymer, di represents the specific gravity of the wall material of the hollow polymer.

(Middle layer)
An intermediate layer may be formed between the receiving layer and the heat insulating layer. For example, a white background adjusting layer, a charge adjusting layer, an adhesive layer, a primer layer, and an undercoat layer are formed. About these layers, it can be set as the structure similar to what was described, for example in patent 3585599 specification, patent 2925244 specification.

(Support)
In the present invention, it is preferable to use a water-resistant support as the support. By using a water-resistant support, it is possible to prevent moisture from being absorbed into the support, and to prevent a change in performance of the receiving layer over time. As the water-resistant support, for example, coated paper or laminated paper can be used. Of these, laminated paper is preferable in terms of surface smoothness. Similar to polyethylene laminated paper (sometimes abbreviated as WP paper) used for photographic paper in the field of silver salt photography, that is, a support mainly composed of cellulose, and at least a receiving layer is applied. A support having a surface coated with a polyolefin resin can be suitably used.

-Coated paper-
The coated paper is a paper obtained by coating various sheets of resin, rubber latex, or polymer material on one side or both sides of a sheet such as a base paper, and the coating amount varies depending on the application. Examples of such coated paper include art paper, cast coated paper, Yankee paper, and the like.

  As the resin applied to the surface of the base paper or the like, it is appropriate to use a thermoplastic resin. Examples of such a thermoplastic resin include the following thermoplastic resins (a) to (h).

(A) Polyolefin resins such as polyethylene resins and polypropylene resins, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, acrylic resins, and the like.
(B) A thermoplastic resin having an ester bond. For example, dicarboxylic acid components (these dicarboxylic acid components may be substituted with sulfonic acid groups, carboxyl groups, etc.) and alcohol components (these alcohol components may be substituted with hydroxyl groups, etc.) Polyester resin, polymethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polybutyl acrylate and other polyacrylate resin or polymethacrylate resin, polycarbonate resin, polyvinyl acetate resin, styrene acrylate resin, styrene -Methacrylic acid ester copolymer resin, vinyl toluene acrylate resin, etc. are mentioned.
Specific examples include those described in JP-A Nos. 59-101395, 63-7971, 63-7972, 63-7773, and 60-294862. it can.
Commercially available products include Byron 290, Byron 200, Byron 280, Byron 300, Byron 103, Byron GK-140, Byron GK-130 manufactured by Toyobo Co., Ltd., Tufton NE-382, Tufton manufactured by Kao Corporation U-5, ATR-2009, ATR-2010; Elitel UE3500, UE3210, XA-8153, KZA-7049, KZA-1449 manufactured by Unitika Ltd. Polyester TP-220, R manufactured by Nippon Synthetic Chemical Co., Ltd. -188; various types of thermoplastic resins (all are trade names) of the high loss series manufactured by Seiko Chemical Industry Co., Ltd.

(C) Polyurethane resin etc. are mentioned.
(D) Polyamide resin, urea resin, etc. are mentioned.
(E) Polysulfone resin and the like.
(F) Polyvinyl chloride resin, polyvinylidene chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl propionate copolymer resin, and the like.
(G) Cellulose resins, such as polyol resin, ethyl cellulose resin, cellulose acetate resin, etc., such as polyvinyl butyral.
(H) Polycaprolactone resin, styrene-maleic anhydride resin, polyacrylonitrile resin, polyether resin, epoxy resin, phenol resin and the like.
In addition, the said thermoplastic resin may be used individually by 1 type, and may use 2 or more types together.

  Further, the thermoplastic resin may contain pigments or dyes such as brighteners, conductive agents, fillers, titanium oxide, ultramarine blue, and carbon black as required.

-Laminated paper-
The laminated paper is a paper obtained by laminating various resins, rubber or polymer sheets or films on a sheet such as a base paper. Examples of the laminate material include polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate, polycarbonate, polyimide, triacetyl cellulose, and the like. These resins may be used alone or in combination of two or more.

  In general, the polyolefin is often formed using low density polyethylene, but in order to improve the heat resistance of the support, polypropylene, a blend of polypropylene and polyethylene, high density polyethylene, high density polyethylene and low density polyethylene, It is preferable to use a blend of In particular, it is most preferable to use a blend of high-density polyethylene and low-density polyethylene from the viewpoint of cost, suitability for lamination, and the like.

The blend of the high density polyethylene and the low density polyethylene is used, for example, in a blend ratio (mass ratio) of 1/9 to 9/1. The blend ratio is preferably 2/8 to 8/2, and more preferably 3/7 to 7/3. When forming a thermoplastic resin layer on both surfaces of the support, the back surface of the support is preferably formed using, for example, high-density polyethylene or a blend of high-density polyethylene and low-density polyethylene. The molecular weight of polyethylene is not particularly limited, but the melt index is 1.0 to 40 g / 10 min for both high-density polyethylene and low-density polyethylene and has extrudability. preferable.
In addition, you may perform the process which gives white reflectivity to these sheets or films. Examples of such a treatment method include a method of blending a pigment such as titanium oxide in these sheets or films. This is generally used as a support for photographic paper in the field of silver salt photography (sometimes abbreviated as WP paper).

  The thickness of the support is preferably 25 μm to 300 μm, more preferably 50 μm to 260 μm, and still more preferably 75 μm to 220 μm. Various stiffnesses can be used according to the purpose of the support. As a support for a thermal transfer image-receiving sheet of photographic quality, a support for color silver salt photographic paper is used. Close ones are preferred.

(Curl adjustment layer)
If the support is exposed as it is, the heat-sensitive transfer image-receiving sheet may be curled due to the humidity and temperature in the environment. Therefore, it is preferable to form a curl adjusting layer on the back side of the support. The curl adjusting layer not only prevents the image receiving sheet from curling but also serves as a waterproof. For the curl adjusting layer, polyethylene laminate, polypropylene laminate, or the like is used. Specifically, it can be formed in the same manner as described in, for example, JP-A-61-110135 and JP-A-6-202295.

(Writing layer / Charge adjustment layer)
An inorganic oxide colloid, an ionic polymer, or the like can be used for the writing layer and the charge adjusting layer. As the antistatic agent, for example, a cationic antistatic agent such as a quaternary ammonium salt or a polyamine derivative, an anionic antistatic agent such as an alkyl phosphate, or a nonionic antistatic agent such as a fatty acid ester can be used. . Specifically, it can be formed in the same manner as that described in, for example, Japanese Patent No. 3585585.

  In the present invention, the plurality of layers are composed mainly of a resin. The coating solution for forming each layer is preferably a polymer latex. The solid content weight of the latex resin in the coating solution of each layer is preferably in the range of 5 to 80%, particularly preferably in the range of 20 to 60%. The average particle size of the resin contained in the polymer latex is 5 μm or less, and particularly preferably 1 μm or less. The polymer latex may contain a known additive such as a surfactant, a dispersant, and a binder resin as necessary.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these. In Examples, “part” or “%” is based on mass unless otherwise specified.

(Production of image receiving sheet)
On the support prepared as described above, an undercoat layer 1, an undercoat layer 2, a heat insulating layer, and a receiving layer were formed in order from the lower layer. The composition and coating amount of the coating solution are shown below.
The coating is performed by the slide coating described above, and after passing through the 6 ° C. set zone for 30 seconds, the fluidity of the liquid is lost. The image receiving sheets (samples 101 to 114) were prepared by spraying on the coated surface and drying for 2 minutes each time when using the above apparatus, and for 2 minutes when drying with only one apparatus.
In the above drying process, a moisture meter (Near-infrared moisture content meter SCM-750 manufactured by Organo) and a thermometer (FUSO-309, thermocouple TPK-04 manufactured by FUSO) are online so that feedback can be applied to the temperature and humidity conditions. The temperature and humidity conditions were controlled by an automatically controlled heater according to the moisture content of the coating film and the film surface temperature. In addition, when using a plurality of drying apparatuses, the conditions can be set independently, and the above automatic temperature and humidity control sequence is incorporated in each device.

Undercoat layer 1 coating liquid (composition)
An aqueous solution obtained by adding 1% sodium dodecylbenzenesulfonate to a 3% gelatin aqueous solution.
Adjust pH to 8 with NaOH (application amount) 11 ml / m ²

Undercoat layer 2 coating liquid (composition)
60 parts by mass of styrene-butadiene latex (SR103 manufactured by Nippon A & L Co., Ltd.)
Polyvinyl alcohol (PVA) 6% aqueous solution 40 parts by weight Surfactant 1% aqueous solution (BFS-1) 2 parts by weight Adjust pH to 8 with NaOH (coating amount) 11 ml / m ²
(Coating solution viscosity) 50cp
(Emulsion creation)
Emulsified dispersion A was prepared by the following procedure. Compound EB-9 was dissolved in 42 g of a high boiling point solvent (Solv-5) and 20 ml of ethyl acetate, and this liquid was dissolved in 250 g of a 20% by weight gelatin aqueous solution containing 1 g of sodium dodecylbenzenesulfonate by a high-speed stirring emulsifier (dissolver). Emulsified and dispersed, and water was added to prepare 380 g of Emulsion A.
Here, the amount of Compound EB-9 added was adjusted to 30 mmol in Emulsion A.

(Preparation of emulsified dispersion B)
High boiling point solvent (Solv-5) 11.0 g, KF-96 (dimethyl silicone manufactured by Shin-Etsu Chemical Co., Ltd.) 9 g, (EB-9) 15.5 g, KAYARAD DPCA-30 (trade name, Nippon Kayaku Co., Ltd.) (Product made) Dissolve in 7.5 g and 20 ml of ethyl acetate. This solution is emulsified and dispersed in 250 g of a 20% by weight gelatin aqueous solution containing 1 g of sodium dodecylbenzenesulfonate with a high-speed stirring emulsifier (dissolver), and water is added. 380 g of Emulsion B was adjusted.

Heat insulation layer coating liquid (composition)
Emulsion A prepared earlier 21 parts by mass Hollow polymer 48 parts by mass (MH5055 manufactured by Nippon Zeon Co., Ltd.)
10% aqueous gelatin solution 28 parts by weight Water 3 parts by weight Preservative (compound represented by formula PR-1) 0.2 parts by weight Adjust pH to 8 with NaOH (amount of application) 50 ml / m ²
(Coating liquid viscosity) 45cp

Receiving layer coating liquid (composition)
Emulsified B prepared earlier 4 parts by weight Vinyl chloride polymer latex 53 parts by weight (Nishin Chemical Co., Ltd., Viniblanc 900)
10 parts by weight of vinyl chloride polymer latex (Nishin Chemical Co., Ltd. BiniBran 276)
6 parts by weight of microcrystalline wax (EMUSTAR-42X manufactured by Nippon Wax Co., Ltd.)
Water 22 parts by weight Surfactant 1% aqueous solution (BFS-1) 4 parts by weight Matting agent 1 part by weight (Melamine-silica resin specific gravity 1.65 (Opto beads 3500M manufactured by Nissan Chemical Industries, Ltd.))
Preservative (compound represented by formula PR-1) 0.1 part by mass Adjusting pH to 8 with NaOH (application amount) 18 ml / m ²

(Preparation of ink sheet)
A polyester film having a thickness of 6.0 μm (Lumirror, trade name, manufactured by Toray Industries, Inc.) was used as a base film. A heat-resistant slip layer (thickness 1 μm) was formed on the back side of the film, and yellow, magenta and cyan compositions having the following compositions were applied to the surface side in a single color (coating amount 1 g / m ² during dry film formation).
Yellow composition Dye (Macrolex Yellow 6G, trade name, manufactured by Bayer) 5.5 parts by weight Polyvinyl butyral resin 4.5 parts by weight (ESREC BX-1, trade name, manufactured by Sekisui Chemical Co., Ltd.)
Methyl ethyl ketone / toluene (mass ratio 1/1) 90 parts by mass Magenta composition Magenta dye (Disperse Red 60) 5.5 parts by mass Polyvinyl butyral resin 4.5 parts by mass (ESREC BX-1, trade name, Sekisui Chemical Co., Ltd.) Manufactured by)
Methyl ethyl ketone / toluene (mass ratio 1/1) 90 parts by mass Cyan composition Cyan dye (Solvent Blue 63) 5.5 parts by mass Polyvinyl butyral resin 4.5 parts by mass (ESREC BX-1, trade name, Sekisui Chemical Co., Ltd.) ) Made)
90 parts by mass of methyl ethyl ketone / toluene (mass ratio 1/1)

[Preparation of protective layer sheet]
A protective layer and an adhesive layer having the following composition were applied to the same polyester film used for preparing the ink sheet. The coating amount at the time of dry film protective layer 1 g / ^{m 2,} and an adhesive layer 0.7 g / ^{m 2.} The adhesive layer was applied on the protective layer after coating and drying.
Protective layer Acrylic resin 20 parts by mass (Dianar BR-80, trade name, manufactured by Mitsubishi Rayon Co., Ltd.)
Methyl ethyl ketone / toluene (mass ratio 1/1) 80 parts by mass adhesive layer polyester resin 30 parts by mass (Byron 220, trade name, manufactured by Toyobo Co., Ltd.)
Methyl ethyl ketone / toluene (mass ratio 1/1) 70 parts by mass

(Image formation)
Using the ink sheet, the protective layer sheet, and the image receiving sheet, a thermal transfer type printer A (manufactured by ASK2000 FUJIFILM Corporation) or a thermal transfer type printer B (the printer described in FIG. 6 of JP-A-5-278247) Was used to output a 152 mm × 102 mm size image. The conveyance speed of the printer A was 73 mm / second. The thermal transfer printer B performed printing by setting the conveyance speed of the thermal transfer image-receiving sheet during image formation to 125 mm / second. At this time, the amount of heat generated by the thermal head was adjusted so that a density gradation equivalent to that obtained when printing with the thermal transfer printer A was obtained.

(Performance evaluation)
Performance evaluation was performed on the following items.
(Curl characteristics)
10 solid black images are output continuously, and left for 1 hour in an environment of 25 ° C. and 55% RH with the marking screen on top of the flat plate, and the height T from the flat plate at the four corners is JIS 1 Measured with a metal scale, the average value was calculated, and evaluated according to the following rank.
5: T ≦ 0.5 mm
4: 0.5 mm <T ≦ 2.0 mm
3: 2.0 mm <T ≦ 4.0 mm
2: 4.0 mm <T ≦ 6.0 mm
1: 6.0 mm <T

(White defect)
Ten continuous black images were output, and the presence or absence of white spots (white spot failure) in the printed solid images was visually observed, and the white spot failure level was evaluated according to the following criteria. This evaluation was performed for 20 evaluators, and the average value of the 20 evaluation values was obtained.
5: Occurrence of white spots in the image cannot be confirmed at all. 4: Occurrence of white spots in the image can hardly be confirmed. 3: Occurrence of white spots in the image is recognized, but there is no practical problem. Level 2: Occurrence of white spots in the image is sporadic, and this is a practically problematic level. 1: Occurrence of white spots in the image is frequent, which hinders recognition of printed images. Is level

(Dmax)
A black solid image was output and the maximum color density was measured. The visual density measurement was performed, and the value relative to the sample 101 was shown in the table. A larger value is preferable because the tightening of the image is increased.

Samples 111 and 112 were prepared by coating the sample 108 without coating the undercoat layer, the heat-insulating layer, and the receiving layer, respectively, by coating and drying one layer at a time.
Samples 113 and 114 were prepared in the same manner except that the hollow polymer of the heat insulating layer was removed from Samples 103 and 108, respectively.
The results are shown in the table below.
In the following table, “drying conditions” represents a ratio of a constant rate drying rate and a reduced rate drying rate. As the rate of decrease drying rate at which the rate does not become constant, the average value of the rates after 5 seconds and 10 seconds after reaching the reduced rate drying region of the coating film was calculated and used. The speed was calculated from the difference between the dry bulb temperature and the coating film surface temperature in the apparatus, and the drying speed coefficient (unit: gH ² O / min · m ² · ° C.) specific to the drying apparatus. In addition, in the drying apparatus, it was confirmed in advance that the film surface temperature and the wet bulb temperature in the apparatus almost coincided during the constant rate drying period.
Drying condition = (average value of speed after 5 seconds after reaching the reduced rate drying zone) / (constant rate drying speed)

  As is apparent from the results in the table, it can be seen that the thermal transfer image-receiving sheet of the present invention has no white spot failure and excellent curl characteristics as compared with the comparative example. Moreover, it turns out that the effect of the drying conditions of this invention exhibits a particularly favorable effect, when simultaneous multilayer coating is performed and when a hollow polymer is used for a heat insulation layer.

Claims (4)

  Thermal transfer having at least one heat insulating layer containing at least one hollow polymer on the support, at least one receiving layer containing at least one polymer latex, and at least two layers formed by simultaneous aqueous multilayer coating The image receiving sheet is dried by at least two or more apparatuses capable of setting at least two or more different temperature and humidity conditions after coating, and the decreasing rate drying rate at the time of drying is 0.2 to 0.2 of the constant rate drying rate. A thermal transfer image-receiving sheet having a magnification of 0.8 times.   The polymer latex contained in the receptor layer is any one or any combination of vinyl chloride / acrylic compound copolymer latex, vinyl chloride / vinyl acetate copolymer latex, vinyl chloride / vinyl acetate / acrylic compound copolymer latex. The heat-sensitive transfer image-receiving sheet according to claim 1, wherein   Thermal transfer having at least one heat insulating layer containing at least one hollow polymer on the support, at least one receiving layer containing at least one polymer latex, and at least two layers formed by simultaneous aqueous multilayer coating A method for producing an image receiving sheet, which is dried by at least two or more apparatuses capable of setting at least two different temperature and humidity conditions after coating, and the reduced rate drying rate at the time of drying is 0 of the constant rate drying rate. A method for producing a thermal transfer image-receiving sheet, wherein the ratio is 2 to 0.8 times.   The polymer latex contained in the receptor layer is any one or any combination of vinyl chloride / acrylic compound copolymer latex, vinyl chloride / vinyl acetate copolymer latex, vinyl chloride / vinyl acetate / acrylic compound copolymer latex. The method for producing a thermal transfer image-receiving sheet according to claim 3, wherein: