JP2008006752A - Thermal transfer image-receiving sheet - Google Patents

Abstract

The present invention provides a thermal transfer image-receiving sheet capable of forming a high-quality image having a high density and no image defects and having excellent fastness of the obtained image.
A copolymer comprising a heat insulating layer containing at least a water-soluble polymer and a foamed hollow polymer on at least one surface of a sheet-like support mainly composed of cellulose pulp, and a repeating unit obtained from vinyl chloride. A heat-sensitive transfer image-receiving sheet in which a receiving layer containing a polymer latex having an average particle size of less than 1.0 μm is sequentially laminated.
[Selection figure] None

Description

  The present invention relates to a heat-sensitive transfer image-receiving sheet that is used in combination with a heat-sensitive transfer sheet (ink sheet) containing a dye.

  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.

  In this type of image receiving sheet, a receiving layer for transferring the transferred dye is formed on the support, and in general, in order to improve the adhesion between the image receiving sheet and the transfer sheet, A layer having high cushioning properties such as a foamed layer made of a resin and a foaming agent or a porous layer containing a hollow polymer is formed between the layers (see, for example, Patent Document 1).

Patent Document 1 discloses forming an image-receiving sheet having a heat insulating layer having a hollow polymer on a support, but when a polyester resin is used for the image-receiving layer, it has a dyeing property and a fading property. There is a problem of being insufficient. Moreover, since these methods form a heat insulating layer on a substrate by a coating method, it is generally difficult to obtain a uniform and smooth image receiving sheet. Since the unevenness on the surface of the image receiving sheet causes transfer loss and printing failure, a smoother image receiving sheet is required.
JP 2006-82382 A “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

  An object of the present invention is to provide a heat-sensitive transfer image-receiving sheet that can overcome the above-mentioned problems, can form a high-quality image having high density and no image defects, and is excellent in the robustness of the obtained image.

As a result of intensive studies, the present inventors have achieved the above-described problem by the following means.
(1) From a copolymer containing a repeating unit obtained from vinyl chloride and a heat insulating layer containing at least a water-soluble polymer and a foamed hollow polymer on at least one surface of a sheet-like support mainly composed of cellulose pulp. A heat-sensitive transfer image-receiving sheet, comprising: a polymer latex comprising a polymer latex having an average particle size of less than 1.0 μm.
(2) The heat insulating layer is formed from a heat insulating layer coating material in which the density of the coating liquid / the calculated density of the coating liquid is a density ratio of 0.7 to 1.2. Thermal transfer image-receiving sheet.
(3) The thermal transfer image-receiving sheet as described in (1) or (2), wherein the hollow polymer has an average particle size of 0.5 to 10 μm.
(4) The heat-sensitive transfer image-receiving sheet as described in any one of (1) to (3), wherein the hollow polymer contained in the heat insulating layer has a hollow ratio of 75 to 95%.
(5) The heat-sensitive transfer image-receiving sheet according to any one of (1) to (4), wherein the heat insulating layer has a thickness of 10 to 110 μm.
(6) The heat-sensitive transfer image-receiving sheet according to any one of (1) to (5), wherein the mass ratio of the hollow polymer to the total solid mass of the heat insulating layer coating solution is 30 to 75%.

  According to the present invention, it is possible to provide a heat-sensitive transfer image-receiving sheet that can form a high-density image having a high density and no image defects, and is excellent in the fastness of the obtained image.

  Hereinafter, the present invention will be described in detail.

In a receiving sheet having a heat insulating layer containing a hollow polymer, if the hollow polymer aggregates are interposed in the heat insulating layer, the smoothness of the receiving layer is lowered and a uniform image is difficult to obtain, but the voids of the aggregates are not obtained. Since it has a heat insulating property, a thermal transfer receiving paper with very high sensitivity can be obtained. However, when thermal printing or sublimation thermal transfer, such as thermal transfer or sublimation thermal transfer, which prints continuously with yellow, magenta, or cyan, is used, the aggregates in the heat insulating layer are not heated by the thermal head during printing or the thermal head and platen. Due to the pressure of the roll, it is crushed during yellow printing of the first color, and after the second color, the heat insulation effect due to the voids inside the agglomerates cannot be used effectively, and dye transfer from the second color onward is not performed sufficiently. Further, since the aggregates are crushed, a uniform image cannot be obtained, the heights of the high density printed portion and the low density portion after printing are generated, and the commercial value is remarkably lowered. In addition, since the binder resin used for the heat insulating layer is softened under high humidity conditions, the aggregates are crushed significantly, and extremely deteriorated such as a decrease in printing density and a feeling of unevenness after printing.

  According to the present invention, since the hollow polymer agglomerates are extremely small, and the receiving layer polymer is a high-modulus vinyl chloride latex having a controlled particle size and closely packed, There was almost no crushing during yellow printing of the first color due to heat or pressure of the thermal head and the platen roll, dye transfer after the second color was sufficiently performed, and excellent color fading and releasability were excellent. An image-receiving sheet having performance can be easily obtained.

(Layer structure of thermal transfer image-receiving sheet)
The heat-sensitive transfer image-receiving sheet of the present invention has at least one receptor layer (dye receptor layer) on a support, and at least one heat insulating layer (porous layer) between the support and the receptor layer. Have. Moreover, you may have base layers, such as a white background adjustment layer, a charge control layer, an adhesive layer, a primer layer, between the receiving layer and a heat insulation layer, for example. It is preferable that a curl adjusting layer, a writing layer, and a charge adjusting layer are formed on the back side of the support.
The receiving layer, the heat insulating layer, and other layers can be performed by a known general coating method. Specifically, a roll coat, a bar coat, a gravure coat, a gravure reverse coat, a die coat, a slide coat curtain coat and the like can be raised. These layers may be applied and dried independently to form necessary layers sequentially, or a plurality of arbitrary layers may be simultaneously laminated. Moreover, you may apply | coat by what is called Wet on Wet. From the viewpoint of productivity, it is desirable to form a plurality of layers that can be stacked by simultaneous multilayer coating. In addition, when a plurality of layers are successively applied to the layer adjacent to the support, it is possible to improve productivity by putting a smoothing process between them and applying the next layer thereon. This is also an effective method. After coating all the layers, a smoothing treatment can be performed. For the smoothing process, a thermal calendar process or a similar method is used.

(Receptive layer)
The receiving layer serves to receive the dye transferred from the ink sheet and maintain the formed image. The image-receiving sheet used in the present invention has at least one receiving layer having a thermoplastic receiving polymer capable of receiving at least a dye.
The accepting polymer is preferably used as a polymer latex dispersed in a water-soluble dispersion medium. Furthermore, the receiving layer preferably contains a water-soluble polymer in addition to the polymer latex. By containing a polymer latex and a water-soluble polymer, a water-soluble polymer that is difficult to be dyed on the dye can be present between the polymer latexes, and the dye dyed on the polymer latex can be prevented from diffusing. Thus, it is possible to reduce a change in sharpness of the receiving layer with time and to form a recorded image with a small change in transfer image with time.
For the receiving layer, in addition to the polymer latex of the receiving polymer, for example, a polymer latex having other functions can be used in combination for the purpose of adjusting the elastic modulus of the film.

<Polymer latex>
The polymer latex used in the present invention will be described.
The polymer latex that can be used in the receiving layer in the heat-sensitive transfer image-receiving sheet of the present invention is obtained by dispersing a water-insoluble hydrophobic polymer as fine particles in a water-soluble dispersion medium. Several different types of polymer latex may be used in combination as the polymer latex, but the polymer latex used in the present invention contains at least vinyl chloride as a monomer unit, that is, a copolymer containing a repeating unit obtained from vinyl chloride. At least one kind of polymer latex is used.
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.

<Average particle size>
The particle size of the polymer latex is desirably smaller than the film thickness of the image receiving layer, and the average particle size is preferably less than 1.0 μm, more preferably in the range of about 0.05 to 0.5 μm. When the average particle size is 1.0 μm or more, coarse particles exist from the particle size distribution, which causes image defects.
The particle size distribution is such that the value σ / Rn (= the coefficient of variation of the particle size distribution, that is, the particle size distribution) obtained by dividing the standard deviation of the particle size distribution of the dispersed particles by the number average particle size is 0.3 or less. By using a narrow material, defects generated by coarse particles are improved, and a dense receiving layer having high strength can be obtained by dense packing. The variation coefficient is more preferably 0.15 or less. The particle size of the emulsion containing vinyl chloride can be adjusted and synthesized by the method described in JP-A-11-124530.

  The average particle size and particle size distribution can be measured, for example, with a laser diffraction / scattering particle size distribution measuring apparatus LA-920 (manufactured by Horiba, Ltd.).

  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 of the polymer latex used in the present invention is preferably −30 ° C. to 100 ° C., more preferably 0 ° C. to 80 ° C., further preferably 10 ° C. to 70 ° C., and particularly preferably 15 ° C. to 60 ° C.

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 mass 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)” (by J. Brandrup, EH Immergut (Wiley-Interscience, 1989)).

  Preferred embodiments of the polymer latex comprising a copolymer containing repeating units obtained from vinyl chloride used in the receiving layer in the present invention include polyvinyl chlorides, copolymers containing vinyl chloride as monomer units, such as vinyl chloride acetic acid. A vinyl copolymer or a vinyl chloride acrylic copolymer polymer can be preferably used. In this case, the ratio of the vinyl chloride monomer is preferably 50% or more and 95% or less. These polymers may be linear polymers, branched polymers, crosslinked polymers, so-called homopolymers obtained by polymerizing a single monomer, or copolymers obtained by polymerizing two or more types of monomers. 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.

  Polymer latex made of a copolymer containing a repeating unit obtained from vinyl chloride that can be used in the present invention is commercially available, and the following polymers can be used. Examples include G351 and G576 manufactured by Nippon Zeon Co., Ltd., Vinibrand 240, 270, 277, 375, 386, 609, 550, 601, 602, 630, 660, 671, 683, 680 manufactured by Nissin Chemical Industry Co., Ltd. 680S, 681N, 685R, 277, 380, 381, 410, 430, 432, 860, 863, 865, 867, 900, 900GT, 938, 950, etc. (all are trade names).

  There are no particular restrictions on polymer latexes having other structures that can be used in combination with latexes containing monomer units of vinyl chloride, but acrylic polymers, polyesters, rubbers (for example, SBR resin), polyurethanes, polyvinyl chloride , Hydrophobic polymers such as polyvinyl acetates, polyvinylidene chlorides and polyolefins can be preferably used. These polymers may be linear polymers, branched polymers, crosslinked polymers, so-called homopolymers obtained by polymerizing a single monomer, or copolymers obtained by polymerizing two or more types of monomers. 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 in combination with the synthesis of a polymer latex having another structure that can be used in combination with a latex containing monomer units used in the present invention is not particularly limited, and may be a normal radical polymerization or ionic polymerization method. In the case of being polymerizable, the monomer groups (a) to (j) shown below can be suitably 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, tetrahydrofurfurylme Chryrate, 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 (eg, monobutyl maleate, dimethyl maleate, monomethyl itaconate, dibutyl itaconate, etc.), polyfunctional esters (eg, ethylene glycol diacrylate) , Ethylene glycol dimethacrylate, 1,4-cyclohexanediacrylate, pentaerythritol tetramethacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, dipentaerythritol pentamethacrylate, pentaerythritol hexaacrylate, 1,2 , 4-cyclohexanetetramethacrylate, etc.).

(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-tertbutyl 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.

  Polymer latex is also commercially available, and the following polymers can be used in combination. 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-121, 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-244L 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, Sephorjon ES manufactured by Sumitomo Seika Co., Ltd. (all 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).

  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.
In the receiving layer in the present invention, the polymer latex containing vinyl chloride as a monomer unit is preferably 50% or more in terms of the total solid content in the layer.

  A polymer latex having another structure used in combination with a latex containing monomer units of vinyl chloride used in the present invention has a glass transition temperature (Tg) of −30 ° C. to 70 ° C. in terms of work brittleness and image storage stability. The thing of the range of ° C is preferable, More preferably, it is the range of -10 degreeC-50 degreeC, More preferably, it is the range of 0 degreeC-40 degreeC. 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.

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. A film-forming auxiliary may be added to control the minimum film-forming temperature. A film-forming aid, also called a temporary plasticizer, is an organic compound (usually an organic solvent) that lowers the minimum film-forming temperature of polymer latex. For example, Soichi Muroi, “Chemistry of Synthetic Latex”, published by Kobunshi Shuppankai (1970) )It is described in. Preferred film-forming aids are the following compounds, but the compounds that can be used in the present invention are not limited to the following specific examples.
Z-1: benzyl alcohol Z-2: 2,2,4-trimethylpentanediol-1,3-monoisobutyrate Z-3: 2-dimethylaminoethanol Z-4: diethylene glycol

  The polymer latex used in the present invention can be easily obtained by a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, an anionic polymerization method, a cationic polymerization or the like. Most preferred. 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, such as inorganic peroxides such as persulfate and hydrogen peroxide, peroxides described in Nippon Oil & Fats Organic Peroxide Catalog, and Wako Pure Chemical Industries, Ltd. The azo compounds described in the azo polymerization initiator catalog can be used. Among these, water-soluble peroxides such as persulfate and water-soluble azo compounds described in the 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, peroxidation such as ammonium persulfate, sodium persulfate, potassium persulfate and the like. The product is preferable from the viewpoint of image preservability, solubility, and cost.

  The addition amount of 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 the monomer. 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, 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 May JP 8-314090, JP-A-10-182571, JP-A-10-182570, can be used the compounds described in JP or the specification of 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, 57-179743, 54-61125, and West German Patent No. 1045373, or the like), a polyphenol chelating agent, Preferably such Riamin based chelate 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 are sodium or 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 chain transfer agent amount 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 based on 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.

The polymer latex used in the present invention is preferably prepared by applying an aqueous coating solution and then drying it. 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.
In addition, the polymer latex in the image-receiving sheet used in the present invention includes a gel or a dried film formed by drying a part of the solvent after coating.

<Water-soluble polymer>
The receiving layer preferably contains a water-soluble polymer. 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. The water-soluble polymer in the present invention does not include the polymer latex.
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)).

Further, it has a superabsorbent polymer described in US Pat. No. 4,960,681, JP-A-62-245260, etc., that is, —COOM or —SO ₃ M (M is a hydrogen atom or an alkali metal). A homopolymer of vinyl monomers or a copolymer 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.) is also used. Can do.

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% by mass, viscosity (4% by mass, 20 ° C.) 39.5 ± 4.5 CPS], PVA-124 [PVA content 94.0% by 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 mass%, saponification degree 97.5 ± 0.5 mol%, sodium acetate content 1.0 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 mass%, 20 ℃) 25.0 ± 3.5CPS] (trade names, available from Kuraray Co.), etc.,

  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% by mass, saponification degree 88.0 ± 1.0 mol%, sodium acetate content 1.0% by mass, volatile content 5. 0% by mass, viscosity (4% by mass, 20 ° C.) 22.5 ± 2.0 CPS], PVA-220 [PVA content 94.0% by 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% by mass, saponification degree 88.0 ± 1.5 mol%, sodium acetate content 1.0% by 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 mass%, saponification degree 88.0 ± 1.0 mol%, sodium acetate content 1.0 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.

  Suitable binders are transparent or translucent, generally colorless, and are natural resins, polymers and copolymers, synthetic resins, polymers and copolymers, and other film-forming media such as rubbers, polyvinyl alcohols, hydroxyethyl celluloses, cellulose Acetates, cellulose acetate butyrate, polyvinylpyrrolidone, starch, polyacrylic acid, polymethylmethacrylic 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, polyvinylidene chlorides, polyepoxides , Polycarbonates, polyvinyl acetates, polyolefins, cellulose esters, and polyamides such water-soluble.

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.

<Hardener>
The hardening agent used in the present invention as a crosslinking agent can be added to a coating layer (for example, a receiving layer, a heat insulating layer, a subbing layer, etc.) of the image receiving sheet.
Examples of the hardening agent that can be used in the present invention include H-1,4,6,8,14 on page 17 of JP-A-1-214845, column 13 to U.S. Pat. No. 4,618,573. 23 compounds (H-1 to 54) represented by formulas (VII) to (XII), compounds (H-1 to 76) represented by formula (6) on page 8, lower right of JP-A-2-214852, In particular, H-14 and the compounds described in claim 1 of US Pat. No. 3,325,287 are preferably used. Examples of hardeners are US Pat. No. 4,678,739, column 41, US Pat. No. 4,791,042, JP-A Nos. 59-116655, 62-245261, and 61-18842. And the hardening agent described in JP-A-4-218444 or the specification thereof. More specifically, aldehyde hardeners (formaldehyde, etc.), aziridine hardeners, epoxy hardeners, vinyl sulfone hardeners (N, N′-ethylene-bis (vinylsulfonylacetamide) Ethane), N-methylol hardeners (dimethylolurea, etc.), boric acid, metaboric acid, or polymer hardeners (compounds described in JP-A-62-234157).
Preferably, a vinyl sulfone type hardener and chlorotriazines are used.
More preferable hardeners in the present invention are compounds represented by the following general formula (B) or (C).
General formula (B)
_{(CH 2 = CH-SO 2} ) n -L
General formula (C)
_{(X-CH 2 -CH 2 -SO} 2) n -L
In general formulas (B) and (C), X represents a halogen atom, and L represents an n-valent organic linking group. When the compound represented by formula (B) or (C) is a low molecular compound, n represents an integer of 1 to 4. In the case of a polymer compound, L is an organic linking group containing a polymer chain, and n is in the range of 10 to 1000.

  In the general formulas (B) and (C), X is preferably a chlorine atom or a bromine atom, more preferably a bromine atom. n is an integer of 1 to 4, preferably an integer of 2 to 4, more preferably an integer of 2 to 3, and most preferably 2.

  L represents an n-valent organic group, preferably an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group, and these groups are ether bond, ester bond, amide bond, sulfonamide bond, urea bond, It may be further connected with a urethane bond or the like. These groups may have a substituent, such as a halogen atom, alkyl group, aryl group, heterocyclic group, hydroxyl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, acyloxy group, alkoxycarbonyl. Groups, carbamoyloxy groups, acyl groups, acyloxy groups, acylamino groups, sulfonamido groups, carbamoyl groups, sulfamoyl groups, sulfonyl groups, phosphoryl groups, carboxyl groups, sulfo groups, etc., halogen atoms, alkyl groups, hydroxy groups, Alkoxy groups, aryloxy groups and acyloxy groups are preferred.

  Specific examples of the vinyl sulfone hardener include the following (VS-1) to (VS-27), but are not limited to these in the present invention.

These hardeners can be obtained by referring to the method described in US Pat. No. 4,173,481.
As the chlorotriazine hardener, a 1,3,5-triazine compound in which at least one chloro atom is substituted at the 2-position, 4-position or 6-position is preferable.
More preferred are those in which 2 or 3 chlorine atoms are substituted at the 2nd, 4th or 6th position. At least one chlorine atom may be substituted at the 2-position, 4-position or 6-position, and a group other than a chlorine atom may be substituted at the remaining positions. Examples of these groups include a hydrogen atom, a bromine atom, Fluorine atom, iodine atom, alkyl group, alkenyl group, alkynyl group, cycloalkyl group, cycloalkenyl group, aryl group, heterocyclic group, hydroxy group, nitro group, cyano group, amino group, hydroxylamino group, alkylamino group, Arylamino group, heterocyclic amino group, acylamino group, sulfonamido group, carbamoyl group, sulfamoyl group, sulfo group, carboxyl group, alkoxy group, alkenoxy group, aryloxy group, heterocyclic oxy group, acyl group, acyloxy group, alkyl Or arylsulfonyl group, alkyl or arylsulfinyl group, alkyl Ku is arylsulfonyloxy group, a mercapto group, an alkylthio group, an alkenylthio group, an arylthio group, a heterocyclic thio group, such as alkyloxy or aryloxy carbonyl group.
Specific examples of chlorotriazine hardeners include 4,6-dichloro-2-hydroxy-1,3,5-triazine or its Na salt, 2-chloro-4,6-diphenoxytriazine, 2-chloro. -4,6-bis [2,4,6-trimethylphenoxy] triazine, 2-chloro-4,6-diglycidoxy-1,3,5-triazine, 2-chloro-4- (n-butoxy) -6 Glycidoxy-1,3,5-triazine, 2-chloro-4- (2,4,6-trimethylphenoxy) -6-glycidoxy-1,3,5-triazine, 2-chloro-4- (2-chloroethoxy ) -6- (2,4,6-trimethylphenoxy) 1,3,5-triazine, 2-chloro-4- (2-bromoethoxy) -6- (2,4,6-trimethylphenoxy) -1, 3,5-tri 2-chloro-4- (2-di-n-butylphosphatoethoxy) -6- (2,4,6-trimethylphenoxy) -1,3,5-triazine, 2-chloro-4- (2 -Di-n-butylphosphatoethoxy) -6- (2,6-xylenoxy) -1,3,5-triazine and the like, but not limited thereto.
Such a compound can be easily produced by reacting cyanuric chloride (that is, 2,4,6-trichlorotriazine) with a hydroxy compound, a thio compound or an amino compound corresponding to a substituent on the heterocyclic ring.

  These hardeners are used in an amount of 0.001 to 1 g, preferably 0.005 to 0.5 g, per 1 g of water-soluble polymer.

<Emulsions>
The receiving layer of the heat-sensitive transfer image-receiving sheet used in the present invention preferably contains an emulsion. The emulsion preferably used in the present invention will be described below.
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.

  As the antioxidant (hereinafter also referred to as a radical scavenger), a compound represented by any one of the following general formulas (E-1) to (E-3) is preferably used.

R ₄₁ is an aliphatic group, aryl group, heterocyclic group, acyl group, aliphatic oxycarbonyl group, aryloxycarbonyl group, aliphatic sulfonyl group, arylsulfonyl group, phosphoryl group, or —Si (R ₄₇ ) (R ₄₈ ). (R ₄₉ ) is represented. Here, R ₄₇ , R ₄₈ and R ₄₉ each independently represents an aliphatic group, an aryl group, an aliphatic oxy group or an aryloxy group. R _{42 to} R ₄₆ represent a hydrogen atom or a substituent. Examples of the substituent include halogen atoms, aliphatic groups (including alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, and cycloalkenyl groups), aryl groups, heterocyclic groups, hydroxy groups, mercapto groups, aliphatic oxy groups. Group, aryloxy group, heterocyclic oxy group, aliphatic thio group, arylthio group, heterocyclic thio group, amino group, aliphatic amino group, arylamino group, heterocyclic amino group, acylamino group, sulfonamide group, cyano group Nitro group, carbamoyl group, sulfamoyl group, acyl group, aliphatic oxycarbonyl group, aryloxycarbonyl group and the like. R _{a1 to} R _a4 each independently represents a hydrogen atom or an aliphatic group (for example, methyl, ethyl).
With respect to the compound represented by any one of the general formulas (E-1) to (E-3), preferred substituents in terms of the effects of the present invention will be described.
In the general formulas (E-1) to (E-3), R ₄₁ is an aliphatic group, an acyl group, an aliphatic oxycarbonyl group, an aryloxycarbonyl group, or a phosphoryl group, and R ₄₂ , R ₄₃ , R ₄₅ And R ₄₆ are each independently preferably a hydrogen atom, an aliphatic group, an aliphatic oxy group or an acylamino group, R ₄₁ is an aliphatic group, and R ₄₂ , R ₄₃ , R ₄₅ and R ₄₆ are It is more preferable that each independently represents a hydrogen atom or an aliphatic group.
Although the preferable specific example represented by either of general formula (E-1)-(E-3) below is shown below, this invention is not limited to these.

  The content of the antioxidant is preferably 1.0 to 7.0% by mass, more preferably 2.5 to 5.0% by mass, based on the solid content in the polymer latex.

  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, and a fluorine-based compound represented by a fluorine-based surfactant, a silicone-based surfactant, a silicone oil such as a silicone oil and / or a cured product thereof is preferably used. The content of the lubricant is preferably 1.0 to 10.0% by mass, more preferably 1.5 to 2.5% by mass, based on the solid content in the polymer latex.

  As the silicone oil as the lubricant, straight silicone oil, modified silicone oil and its cured product can be used. Straight silicone oils include dimethyl silicone oil, methylphenyl silicone oil, and methyl hydrogen silicone oil. Examples of dimethyl silicone oil include KF96-10, KF96-100, KF96-1000, KF96H-10000, KF96H-12500, and KF96H. -100,000 (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like, and examples of dimethyl silicone oil include KF50-100, KF54, KF56 (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.). Can be mentioned.

  The modified silicone oil can be classified into a reactive silicone oil and a non-reactive silicone oil. The reactive silicone oil includes amino modification, epoxy modification, carboxyl modification, hydroxy modification, methacryl modification, mercapto modification, phenol modification, one-terminal reactivity and heterofunctional modification. As amino-modified silicone oil, KF-393, KF-857, KF-858, X-22-3680, X-22-3801C, KF-8010, X-22-161A, KF-8012 (all trade names, Shin-Etsu Chemical Co., Ltd.) and the like, and epoxy-modified silicone oils include KF-100T, KF-101, KF-60-164, KF-103, X-22-343, X-22-3000T ( All of them are trade names, manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of the carboxyl-modified silicone oil include X-22-162C (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of the hydroxy-modified silicone oil include X-22-160AS, KF-6001, KF-6002, KF-6003, X-22-170DX, X-22-176DX, X-22-176D, X-22-176DF (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like, methacryl-modified silicone oil X-22-164A, X-22-164C, X-24-8201, X-22-174D, X-22-2426 (all are trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. .

  The reactive silicone oil can be used after being cured, and can be classified into a reaction curable type, a photo curable type, a catalyst curable type, and the like. Of these, reaction-curable silicone oils are particularly preferable. As the reaction-curable silicone oils, those obtained by reaction-curing amino-modified silicone oil and epoxy-modified silicone oil are preferable. Further, as the catalyst curable type or photo curable type silicone oil, KS-705F-PS, KS-705F-PS-1, KS-770-PL-3 [catalyst curable type silicone oil: all trade names, Shin-Etsu Chemical Co., Ltd. KS-720, KS-774-PL-3 [photocured silicone oil: trade names, manufactured by Shin-Etsu Chemical Co., Ltd.], and the like. The addition amount of these curable silicone oils is preferably 0.5 to 30% by mass of the resin constituting the receiving layer. The release agent is used in an amount of 2 to 4% by mass, preferably about 2 to 3% by mass, based on 100 parts by mass of the polyester resin. If the amount is too small, the releasability cannot be ensured, and if the amount is too large, the protective layer will not be transferred to the image receiving sheet.

  Non-reactive silicone oils include polyether modification, methylstyryl modification, alkyl modification, higher fatty acid ester modification, hydrophilic special modification, higher alkoxy modification, fluorine modification and the like. Polyether-modified silicone (KF-6012, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) can be mentioned, and methylstil-modified silicone silicone oils (24-510, KF41-410, both trade names, Shin-Etsu Chemical ( Etc.). Moreover, the modified silicone represented by either of the following general formulas 1-3 can also be used.

  In General Formula 1, R represents a hydrogen atom, an aryl group, or a linear or branched alkyl group that may be substituted with a cycloalkyl group. m and n represent an integer of 2000 or less, and a and b represent an integer of 30 or less.

  In General Formula 2, R represents a hydrogen atom, an aryl group, or a linear or branched alkyl group which may be substituted with a cycloalkyl group. m represents an integer of 2000 or less, and a and b represent an integer of 30 or less.

  In General Formula 3, R represents a hydrogen atom, an aryl group, or a linear or branched alkyl group which may be substituted with a cycloalkyl group. m and n represent an integer of 2000 or less, and a and b represent an integer of 30 or less. R1 represents a single bond or a divalent linking group, E represents an ethylene group which may have a substituent, and P represents a propylene group which may have a substituent.

  Silicone oils such as those described above are described in “Silicone Handbook” (published by Nikkan Kogyo Shimbun Co., Ltd.), and are described in JP-A-8-108636 and JP-A-2002-264543 as curing technologies for curable silicone oils. The technique can be preferably used.

High boiling point organic solvents include phthalates (dibutyl phthalate, dioctyl phthalate, di-2-ethylhexyl phthalate, etc.), phosphoric acid or phosphonic esters (triphenyl phosphate, tricresyl phosphate, triphosphate phosphate) -2-ethylhexyl, etc.), fatty acid esters 塁 (di-2-ethylhexyl succinate, tributyl citrate, etc.), benzoates (2-ethylhexyl benzoate, dodecyl benzoate, etc.), amides (N, N-diethyl, etc.) Dodecanamide, N, N-dimethyloleamide, etc.), alcohol or phenols (isostearyl alcohol, 2,4-di-tert-amylphenol, etc.), anilines (N, N-dibutyl-2-butoxy-5-) tert-octylaniline, etc.), chlorinated paraffins, hydrocarbons (dode) Rubenzen, diisopropyl naphthalene), carboxylic acids (2- (2,4-di -tert- amylphenoxy) butyric acid, and the like.
The following compounds are preferably used.

  Further, an organic solvent (such as ethyl acetate, butyl acetate, methyl ethyl ketone, cyclohexanone, or methyl cellosolve acetate) having a boiling point of 30 ° C. or higher and 160 ° C. or lower may be used in combination as an auxiliary solvent. The amount of the high-boiling organic solvent is 10 g or less, preferably 5 g or less, more preferably 1 g to 0.1 g based on 1 g of the hydrophobic additive used. In addition, 1 milliliter or less, further 0.5 milliliter or less, particularly 0.3 milliliter or less is appropriate for 1 g of binder.

A dispersion method using a polymer described in JP-B-51-39853 and JP-A-51-59943, or a fine particle dispersion described in JP-A-62-22422, etc. Can also be used. In the case of a compound that is substantially insoluble in water, in addition to this method, it can be dispersed and contained as fine particles in a binder.
In dispersing the hydrophobic compound in the hydrophilic colloid, various surfactants can be used. For example, the surfactants described in JP-A No. 59-157636, pages 37 to 38 can be used. Further, phosphate ester type surfactants described in JP-A-7-56267, JP-A-7-228589 and West German Patent No. 1,932,299A or the specification can also be used.

<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, preferably a weight average molecular weight of 10,000 or more, and more preferably a weight 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 grafted with the ultraviolet absorber is made into a latex, a receiving layer in which the ultraviolet absorber is uniformly dispersed can be formed by mixing with the latex of the dyeable receiving polymer and then 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 mold release agent, silicone oil, phosphate ester plasticizer fluorine compound, and various wax dispersions can be used. In particular, silicone oil and wax dispersion are 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. A reaction product of vinyl-modified silicone oil and hydrogen-modified silicone oil is preferable. The addition amount of the release agent is preferably 0.2 to 30 parts by mass with respect to the receiving polymer.

A known dispersion can be used as the wax dispersion. In the present invention, “wax is treated as an organic substance having a solid or semi-solid alkyl chain at normal temperature” (according to the definition of “Revised properties and application of wax” (Shoshobo, 1989)). Examples of preferred compounds include candelilla wax, carnauba wax, rice wax, wood wax, montan wax, ozokerite, paraffin wax, microcrystalline wax, petrolactam, Fischer-Tropsch wax, polyethylene wax, montan wax derivatives, paraffin wax. Derivatives, microcrystalline wax derivatives, hardened castor oil, hardened castor oil derivatives, 12-hydroxystearic acid, stearamide, phthalic anhydride, chlorinated hydrocarbons, and other blended waxes. Of these, carnauba wax, montan wax and derivatives thereof, paraffin wax and derivatives thereof, microcrystalline wax and derivatives thereof, polyethylene wax and stearamide are preferred, kaunauba wax, mondan wax and derivatives thereof, and microcrystalline wax. Stearamide is more preferable, and montan wax and derivatives thereof, and microcrystalline wax are more preferable.
This wax is selected from those having a melting point of 25 ° C to 120 ° C, preferably 40 ° C to 100 ° C, more preferably 60 ° C to 90 ° C.
The wax is preferably an aqueous dispersion, and more preferably finely divided. The water dispersion method and the micronization method can be achieved by the methods described in “Revised Wax Properties and Applications” (Sachibo, 1989).
The addition amount of the wax is preferably 0.5% by mass to 30% by mass, more preferably 1% by mass to 20% by mass, and still more preferably 1.5% by mass to 15% by mass of the total solid content of the receiving layer. .

The coating amount of the receptor 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), and more preferably 1 to 1. 8 g / ^{m 2,} more preferably the coating weight of 2~7g / ^{m 2} is preferred. The thickness of the receiving layer is preferably 1 to 20 μm.

(Insulation layer)
In the present invention, a heat insulating layer is formed on at least one side of a paper base material mainly composed of cellulose pulp as a support. The heat-insulating layer is composed of a binder resin and a hollow polymer as the main components. This heat-insulating layer has a porous structure and high cushioning properties. can get.

The dispersion distribution of the hollow polymer in the heat insulating layer gives the receiving sheet an appropriate degree of deformation freedom, and improves the followability and adhesion of the receiving sheet with respect to the printer head shape and the ink ribbon shape. The thermal efficiency of the head can be improved, and the print density of the printed image can be increased to improve the image quality. Further, in the high energy application operation of the high-speed printer, it is possible to prevent printing defects due to ribbon wrinkles generated on the ink ribbon at the same time.
By dispersing and distributing the hollow polymer in the heat insulating layer, the heat insulating property of the receiving sheet is improved, thereby improving the thermal efficiency of the thermal head with respect to the receiving layer, thereby increasing the print density and improving the image quality.
Even if the receiving sheet is subjected to high pressure by the thermal head and the conveying roll of the printer, this stress can be absorbed inside the receiving sheet. Resistance to formation is improved.

The hollow polymer used in the heat insulating layer of the present invention comprises a shell formed of a polymer material and one or more hollow parts surrounded by the shell, and the maximum particle size of the hollow polymer is 25 μm. The following is preferable, and more preferably 20 μm or less. The average particle diameter of the hollow polymer is preferably 0.5 to 10 μm, more preferably 0.8 to 8 μm. When the average particle size of the hollow polymer is less than 0.5 μm, the volume hollow ratio of the obtained hollow polymer is lowered, and the heat insulating property and cushioning property are generally lowered, and the sensitivity and the image quality improvement effect are sufficiently obtained. There may not be. On the other hand, if the average particle diameter exceeds 10 μm, the smoothness of the surface of the heat insulating layer to be obtained is lowered, the unevenness of the surface of the image receiving sheet becomes excessive, the uniformity of the thermal transfer image becomes insufficient, and the image quality is inferior.
Although there is no special restriction | limiting about the manufacturing method of a hollow polymer, It can select from what was manufactured as follows.
[1] A dispersion medium such as water is contained inside the partition formed by polystyrene, acrylic resin, styrene-acrylic resin, etc., and after coating and drying, the dispersion medium in the particles evaporates out of the particles and the inside of the particles is hollow. Non-foamed hollow particles, [2] low-boiling liquids such as butane and pentane, and a thermally expandable substance such as polyvinylidene chloride, polyacrylonitrile, polyacrylic acid, polyacrylic acid ester, or a mixture thereof A foamed microballoon that is covered with a resin made of a polymer and becomes hollow when the low-boiling liquid in the particles expands by heating after coating. [3] The above [2] is heated and foamed in advance. And a microballoon made of a hollow polymer.
In the present invention, among these, at least the already-expanded hollow polymer [3], that is, the micro-balloon that has been previously expanded by heating and foaming is contained. The pre-foamed hollow polymer can increase the average particle size of the obtained particles, can increase the void ratio (hollow ratio) in the polymer particles relatively easily, and provides high heat insulation and cushioning properties. Is possible.

  A hollow polymer in an already foamed state produced by thermally expanding a thermoplastic material containing a thermally expandable material is, for example, a volatile material such as n-butane, i-butane, pentane, and / or neopentane as a thermally expandable core material. Encapsulating low-boiling hydrocarbons in a thermoplastic material, and using a homopolymer or copolymer of vinylidene chloride, acrylonitrile, styrene, (meth) acrylic acid ester, etc. as the capsule shell (wall) material By subjecting the obtained particles to a treatment such as heating in advance, the particles are thermally expanded to a predetermined particle diameter to form an already foamed hollow polymer.

  In addition, the foamed hollow polymer produced by thermally expanding the thermoplastic material-containing thermoplastic material as described above generally has a small specific gravity, so that the handling workability and dispersibility are further improved. A foamed composite hollow polymer in which an inorganic powder such as calcium carbonate, talc, titanium dioxide or the like is adhered to the surface of the foamed hollow polymer by heat fusion and the surface is coated with the inorganic powder can also be used in the present invention.

The particle size distribution of the hollow polymer in the heat insulating layer is preferably 10% or less of particles of 10 μm or more, and more preferably 5% or less.
The maximum particle diameter of the secondary particles of the pre-expanded hollow polymer used in the present invention is preferably 25 μm or less, more preferably 20 μm or less. When the maximum particle size including the secondary particles of the foamed hollow polymer exceeds 25 μm, the thermal transfer image may cause unevenness in density of prints and white spots due to coarse particles, which is not preferable.
In order to obtain a desired particle size distribution, a sand mill (also referred to as “sand grinder”), a cowless, a ball mill, or the like can be used for dispersing the hollow polymer. In general, a sand mill used for dispersion of inorganic pigments and organic pigments is preferably used, and the hollow polymer aggregates are efficiently and uniformly dispersed under conditions where the hollow polymer is not crushed.

  For example, in the case of a sand mill, preferable grinding conditions include clearance: 300 μm to 1 mm, rotation speed: 500 to 3000 rpm, bead material: glass, size: φ1 to 3 mm, filling amount: 40 to 70%, flow rate: 0.5 to Distributed processing is performed at about 51 / min. If the clearance is less than 300 μm, clogging of the dispersion occurs. If the clearance exceeds 1 mm, the beads may break and be mixed into the dispersion. If the rotational speed is less than 500 rpm, the dispersibility may be poor, and if it exceeds 3000 rpm, the viscosity of the dispersion may increase rapidly and the fluidity of the dispersion may be impaired. If the bead filling amount is less than 40%, the shaft of the sand mill may be shaken and good dispersion may not be achieved. If the filling amount exceeds 70%, the hollow polymer may be crushed.

  At the time of dispersion, known additives such as sodium alkylsulfosuccinate, sodium dialkylsulfosuccinate, sodium acrylate, sodium polyphosphate, sodium hexametaphosphate, etc., and hydrophilic such as polyvinyl alcohol resin, cellulose resin and derivatives thereof, casein, starch derivatives, etc. It is also possible to contain and disperse a functional polymer resin, (meth) acrylic acid ester resin, styrene-butadiene copolymer resin, urethane resin, polyester resin, ethylene-vinyl acetate copolymer resin, or the like. The heat-insulating layer coating solution (also referred to as coating solution or paint) prepared using the hollow polymer dispersion thus obtained has good workability regardless of the viscosity of the coating solution.

The coating liquid for forming the heat insulating layer is preferably in a range where the density ratio of the density of the coating liquid / the calculated density of the coating liquid is 0.7 to 1.2, more preferably in the range of 0.8 to 1.1. It is.
Here, the density of the coating liquid is an actual density of the coating liquid, and the calculated density of the coating liquid is a density obtained by calculation obtained from the density of each component before dispersion constituting the coating liquid. If the hollow polymer is partially broken by dispersing the already foamed hollow polymer using each component, the density of the coating solution adjusted by dispersion is different.
That said density ratio is less than 0.7 will contain a lot of foam in a coating liquid. For example, a large amount of fine voids are contained in the heat insulating layer obtained by coating the coating liquid on a sheet-like support and drying it with hot air or the like. The printing density of the image-receiving sheet formed in this way combines the heat insulation effect of the hollow polymer and the heat insulation effect due to fine voids in the coating layer, so the heat insulation is extremely high, but the heat during printing is high. The coating layer is greatly crushed, which significantly impairs the product value, and if printing is performed under high humidity conditions, the coating layer due to moisture is plasticized, so that the coating layer is significantly crushed during printing, and the printing density decreases. End up. On the other hand, the fact that the density ratio of the heat insulating layer paint is higher than 1.2 means that the hollow polymer is crushed at the time of dispersion, and the effect expected from the hollow polymer, cushioning property and heat insulating property cannot be obtained, and the print density and The deterioration in image quality is significant.

The average particle diameter and internal void diameter of the hollow polymer are calculated by measuring at least 300 hollow polymers using a transmission electron microscope, and measuring the outer diameter and the equivalent circular diameter of the internal void. Moreover, the internal void ratio (hollow ratio) of the hollow polymer is calculated by averaging the individual hollow ratios (%) obtained by calculation as follows.
Individual hollow ratio (%) = (internal void diameter) ³ / (particle diameter of hollow polymer) ³ × 100

  The hollow ratio of the hollow polymer used in the present invention is preferably 75 to 95%. If the hollow ratio is less than 75%, the image quality may deteriorate, which is not preferable. On the other hand, if the hollow ratio exceeds 95%, the strength of the coating layer is inferior, the hollow polymer is destroyed during coating drying, and the surface smoothness may be lowered, which is not preferable.

  The blending amount of the hollow polymer in the heat insulating layer is preferably in the range of 30 to 75%, more preferably in the range of 35 to 70% in terms of the ratio of the hollow polymer mass to the total solid mass of the heat insulating layer. When the mass ratio of the hollow polymer to the total solid content mass of the heat insulating layer is less than 30%, the heat insulating property and cushioning property of the heat insulating layer may be insufficient, and the sensitivity and image quality improvement effect may not be sufficiently obtained. On the other hand, when the mass ratio of the hollow polymer exceeds 75%, the coatability of the resulting heat insulating layer coating material is deteriorated, the coating film strength is lowered, and the desired effect may not be obtained.

  As for the film thickness of the heat insulation layer for a heat insulation layer to exhibit performance, such as desired heat insulation and cushioning properties, 10-110 micrometers is preferable, More preferably, it is 20-90 micrometers, Especially preferably, it is 25-85 micrometers. When the film thickness of the heat insulating layer is less than 10 μm, the heat insulating property and the cushioning property may be insufficient, and the sensitivity and the image quality improving effect may be insufficient. On the other hand, if the film thickness exceeds 110 μm, the effects of heat insulation and cushioning are saturated, which is economically disadvantageous.

The heat insulating layer of the present invention contains a hollow polymer and a water-soluble polymer. In consideration of the solvent resistance of the hollow polymer, the heat insulating layer paint of the present invention is preferably an aqueous paint. Accordingly, both water-based and organic solvent-based polymers can be used, but an aqueous resin is more preferable.
The water-soluble polymer to be used is not particularly limited. For example, hydrophilic polymer resins such as polyvinyl alcohol resins, cellulose resins and derivatives thereof, casein, and starch derivatives are film forming property, heat resistance, and flexibility. Are preferably used. Also, emulsions of various resins such as (meth) acrylic acid ester resins, styrene-butadiene copolymer resins, urethane resins, polyester resins, ethylene-vinyl acetate copolymer resins are used as low-viscosity and high-solids aqueous resins. . In view of the coating strength, adhesiveness, and coatability of the heat insulating layer, the water-soluble polymer used in the heat insulating layer is preferably a combination of the hydrophilic polymer resin and an emulsion of various resins.

  For the heat insulating layer, various additives such as antistatic agents, inorganic pigments, organic pigments, resin cross-linking agents, antifoaming agents, dispersing agents, colored dyes, mold release agents, lubricants, and the like as required. Or you may select and use 2 or more types suitably.

  The heat insulating layer of the present invention comprises a coating solution for a heat insulating layer containing at least the required components of a hollow polymer and a water-soluble polymer, a bar coater, a gravure coater, a comma coater, a blade coater, an air knife coater, a gate roll coater, a die coater, Using a known coater such as a curtain coater, a lip coater, a slide bead coater or the like, it can be coated on a sheet-like support according to a conventional method and dried.

  When applying the heat insulating layer, a molding surface may be used, or a metal plate, a metal drum, a plastic film, or the like having good dimensional stability and a highly smooth surface may be used. Moreover, in order to make it easy to peel off the heat insulation layer from the molding surface as necessary, higher mold release agents such as calcium stearate and zinc stearate on the molding surface, polyethylene release agents such as polyethylene emulsion, wax, A release agent such as silicone may be applied.

  In the present invention, calendering after coating of the heat insulating layer, barrier layer, and receiving layer is effective in reducing unevenness on the surface of the receiving sheet and smoothing, and in particular, performing calendering after coating of the heat insulating layer. Is more preferable. There are no particular limitations on the calendar device used for the calendar process, the nip pressure, the number of nips, the surface temperature of the metal roll, and the like. Preferred pressure conditions for performing the calendar process are, for example, 0.5 to 150 mPa, preferably Is 1 to 100 mPa. As the temperature condition, the hollow polymer is not destroyed from room temperature, and is preferably Tg temperature or higher of the binder resin for heat insulating layer, for example, 20 to 150 ° C, more preferably 30 to 120 ° C. As the calendar device, for example, a calendar device generally used in the paper industry such as a super calendar, a soft calendar, and a gloss calendar can be appropriately used.

(Sheet support)
As the sheet-like support of the image-receiving sheet (hereinafter sometimes simply referred to as “support”),
(1) High quality paper, coated paper, art paper, cast coated paper, laminated paper provided with a thermoplastic resin layer such as polyolefin resin on at least one, synthetic resin impregnated paper, emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic Paper mainly composed of cellulose pulp, such as resin-added paper, foamed paper containing thermally expandable particles, and paperboard;
(2) Plastic films mainly composed of thermoplastic resins such as polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polyamides, polyvinyl chloride and polystyrene;
Among the above-mentioned various sheet-like supports, papers mainly composed of cellulose pulp have low heat shrinkability, good heat insulation, good texture as a receiving paper, and a price. Is also inexpensive because it is used in the present invention.

  The sheet-like support of the present invention may have a structure in which a first base material layer on which a receiving layer is formed, an adhesive layer, a release agent layer, and a second base material layer are sequentially laminated. Of course, supports having a type of structure can also be used.

  The sheet-like support used in the present invention preferably has a thickness of 100 to 300 μm. Incidentally, if the thickness is less than 100 μm, the mechanical strength thereof is insufficient, the rigidity of the receiving sheet obtained therefrom is small and the repulsive force against deformation is insufficient, and the receiving sheet curl generated at the time of printing is sufficient. May not be prevented. On the other hand, if the thickness exceeds 300 μm, the thickness of the receiving sheet to be obtained becomes excessive, which may lead to a decrease in the number of receiving sheets stored in the printer. In some cases, this causes an increase and makes it difficult to make the printer compact.

The method for producing the thermal transfer image receiving sheet of the present invention will be described below.
The heat-sensitive transfer image-receiving sheet of the present invention can be formed by sequentially applying at least one receiving layer and a heat insulating layer on a support, or by simultaneous multilayer coating.
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 the present invention, it can be manufactured by sequential coating, but by using the above-mentioned simultaneous multilayer coating for manufacturing a multi-layer image-receiving sheet, productivity can be greatly improved and image defects can be greatly reduced.

  In the present invention, the plurality of layers are composed mainly of a resin. The coating solution for forming each layer is preferably water-dispersed 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 water-dispersed latex is 5 μm or less and particularly preferably 1 μm or less. The water-dispersed latex may contain a known additive such as a surfactant, a dispersant, and a binder resin as necessary.

The thermal transfer sheet (ink sheet) used in combination with the above-described thermal transfer image-receiving sheet of the present invention at the time of thermal transfer image formation is provided with a dye layer containing a diffusion transfer dye on a support. Ink sheets can be used. As the means for applying thermal energy at the time of thermal transfer, any conventionally known means for applying can be used. For example, recording is performed by a recording device such as a thermal printer (for example, product name, video printer VY-100, manufactured by Hitachi, Ltd.). By controlling the time, the intended purpose can be sufficiently achieved by applying thermal energy of about 5 to 100 mJ / mm ² .
The heat-sensitive transfer image-receiving sheet of the present invention can be applied to various uses such as a sheet- or roll-shaped heat-sensitive transfer image-receiving sheet, cards, and transmission-type manuscript preparation sheets capable of thermal transfer recording by appropriately selecting a support. You can also

  The present invention can be used in printers, copiers and the like using a thermal transfer recording system.

  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.

(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 Co., Ltd.) 5.5 parts by mass Polyvinyl butyral resin 4.5 parts by mass (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 vinyl chloride-containing latex A-1)
A vinyl chloride-containing latex A-1 was prepared by the following procedure. In a pressure-resistant polymerizer equipped with a stirrer, thermometer and nitrogen gas inlet, after nitrogen substitution, 750 parts of deionized water, 290 parts of vinyl acetate, 10 parts of acrylic acid, 20 parts of sodium dodecylbenzenesulfonate, polyoxyethylene 20 parts of nonylphenyl ether was charged, the inside of the polymerization vessel was further evacuated, 700 parts of vinyl chloride was charged, and the temperature was raised to 60 ° C. while stirring in a nitrogen gas atmosphere. Next, an aqueous solution in which 5 parts of ammonium persulfate was dissolved in 100 parts of deionized water was injected to start the reaction, the reaction was carried out for 20 hours while maintaining the internal temperature at 60 ° C., and the polymerization was completed by cooling to 30 ° C. did. Table 1 shows the average particle size and particle size distribution of the obtained emulsion.

(Preparation of latex A-2 containing vinyl chloride)
A vinyl chloride-containing latex A-2 was prepared by the following procedure. In a pressure-resistant polymerization reactor equipped with a stirrer, a thermometer and a nitrogen gas inlet, after nitrogen substitution, 1250 parts of deionized water, 170 parts of vinyl acetate, 20 parts of methacrylic acid, 10 parts of N-methylolacrylamide, sodium lauryl sulfate 20 And 20 parts of polyoxyethylene nonylphenyl ether were added, and the inside of the polymerization vessel was further evacuated to charge 800 parts of vinyl chloride, and the temperature was raised to 60 ° C. with stirring in a nitrogen gas atmosphere. Next, an aqueous solution in which 5 parts of ammonium persulfate was dissolved in 100 parts of deionized water was injected to start the reaction, the reaction was carried out for 20 hours while maintaining the internal temperature at 60 ° C., and the polymerization was completed by cooling to 30 ° C. did. Table 1 shows the average particle size and particle size distribution of the obtained emulsion.

(Preparation of vinyl chloride-containing latex A-3)
A vinyl chloride-containing latex A-3 was prepared by the following procedure. In a pressure-resistant polymerization reactor equipped with a stirrer, a thermometer and a nitrogen gas inlet, after substitution with nitrogen, 950 parts of deionized water, 240 parts of vinyl acetate, 10 parts of methacrylic acid, 150 parts of ethyl acrylate, potassium oleate soap 20 And 20 parts of polyoxyethylene nonylphenyl ether were added, and the inside of the polymerization vessel was evacuated to 600 parts of vinyl chloride, and the temperature was raised to 60 ° C. with stirring in a nitrogen gas atmosphere. Next, an aqueous solution in which 5 parts of ammonium persulfate was dissolved in 100 parts of deionized water was injected to start the reaction, the reaction was carried out for 20 hours while maintaining the internal temperature at 60 ° C., and the polymerization was completed by cooling to 30 ° C. did. Table 1 shows the average particle size and particle size distribution of the obtained emulsion.

(Preparation of latex A-4 containing vinyl chloride)
A vinyl chloride-containing latex A-4 was prepared by the following procedure. In a pressure-resistant polymerization reactor equipped with a stirrer, thermometer and nitrogen gas inlet, after nitrogen substitution, 1150 parts of deionized water, 130 parts of vinyl acetate, 70 parts of methacrylic acid, 20 parts of sodium lauryl sulfate, polyoxyethylene nonylphenyl 20 parts of ether was charged, and the inside of the polymerization vessel was further evacuated to charge 400 parts of vinyl chloride, and the temperature was raised to 60 ° C. while stirring in a nitrogen gas atmosphere. Next, an aqueous solution in which 5 parts of ammonium persulfate was dissolved in 100 parts of deionized water was injected to start the reaction, the reaction was carried out for 20 hours while maintaining the internal temperature at 60 ° C., and the polymerization was completed by cooling to 30 ° C. did. Table 1 shows the average particle size and particle size distribution of the obtained emulsion.

(Preparation of vinyl chloride-containing latex A-5)
A vinyl chloride-containing latex A-5 was prepared by the following procedure. In a pressure-resistant polymerizer equipped with a stirrer, a thermometer and a nitrogen gas inlet, after substitution with nitrogen, 1100 parts of deionized water, 660 parts of vinyl acetate, 30 parts of methacrylic acid, 10 parts of 2-hydroxyethyl methacrylate, sodium lauryl sulfate 20 parts and 20 parts of polyoxyethylene nonylphenyl ether were charged, the inside of the polymerization vessel was further evacuated, 150 parts of vinyl chloride was charged, and the temperature was raised to 60 ° C. with stirring in a nitrogen gas atmosphere. Next, an aqueous solution in which 5 parts of ammonium persulfate was dissolved in 100 parts of deionized water was injected to start the reaction, and the reaction was carried out for 5 hours while maintaining the internal temperature at 60 ° C. Then, 150 parts of vinyl chloride was added over 5 hours. The mixture was continuously injected, and the reaction was further carried out at the same temperature for 10 hours, followed by cooling to 30 ° C. to complete the polymerization. Table 1 shows the average particle size and particle size distribution of the obtained emulsion.

(Preparation of vinyl chloride-containing latex B-1)
A vinyl chloride-containing latex B-2 was prepared by the following procedure. In a pressure-resistant polymerization reactor equipped with a stirrer, thermometer and nitrogen gas inlet, after nitrogen substitution, 1150 parts of deionized water, 150 parts of vinyl acetate, 70 parts of acrylic acid, 20 parts of methacrylic acid, 10 parts of N-methylolacrylamide , 5 parts of sodium dodecylbenzenesulfonate and 35 parts of polyoxyethylene nonylphenyl ether were added, and the inside of the polymerization vessel was evacuated to prepare 375 parts of vinyl chloride, and the temperature was raised to 60 ° C. with stirring in a nitrogen gas atmosphere. . Next, an aqueous solution in which 5 parts of ammonium persulfate was dissolved in 100 parts of deionized water was injected to start the reaction, and the reaction was carried out for 5 hours while maintaining the internal temperature at 60 ° C. Then, 375 parts of vinyl chloride was added over 5 hours. The mixture was continuously injected, and further reacted at the same temperature for 10 hours, followed by cooling to 30 ° C. to complete the polymerization. Table 1 shows the average particle size and particle size distribution of the obtained emulsion.

  As the polymer latex B-2, a commercially available polyester latex Vylonal MD-1200 (manufactured by Toyobo Co., Ltd.) was used. Table 1 shows the average particle size and particle size distribution of the emulsion.

  The average particle size and particle size distribution in Table 1 were measured with a laser diffraction / scattering particle size distribution measuring apparatus LA-920 (manufactured by Horiba, Ltd.).

(Creation of image receiving sheet)
(1-1) Preparation of Sample 101 Multi-layer coating composition having a heat insulating layer and a receiving layer in order from the lower layer to art paper (trade name: OK Kanfuji N, 174.4 g / m ² , manufactured by Oji Paper Co., Ltd.) having a thickness of 150 μm. 101-105 were created. The composition and coating amount of the coating solution are shown below.

"Insulation layer"
The hollow polymer dispersion was dispersed by a Cowles blade with the following composition to obtain a dispersion in which the hollow polymer particle size distribution was 5% or less (average particle diameter: 5.0 μm) of 10 μm or more hollow polymer.
Hollow polymer dispersion-1
Matsumoto Microsphere MFL80GSL (Brand name: Matsumoto Yushi Co., Ltd.) 50 parts (Hollow rate 88% Acrylonitrile-based foamed microballoon)
Polyacrylic acid soda 0.1 part polyvinyl alcohol 5 parts (trade name: PVA205, manufactured by Kuraray Co., Ltd., polymerization degree 500)
200 parts of water

  On the sheet-like support, the coating liquid for heat insulation layer-1 having the following composition (heat insulation layer paint density / heat insulation layer paint calculated density = 0.8) was applied and dried so that the film thickness after drying was 43 μm. Thus, a heat insulating layer was formed.

Thermal insulation coating liquid-1
Hollow polymer dispersion liquid-1 250 parts polyvinyl alcohol 5 parts (trade name: PVA205, manufactured by Kuraray Co., Ltd., polymerization degree 500)
40 parts of styrene-butadiene latex (trade name: PT1004, manufactured by Asahi Kasei Corporation)

"Receptive layer"
<Receptive layer coating solution-1>
Vinyl chloride-containing polymer latex A-1 shown in Table 1 70 parts 10% aqueous gelatin solution 10 parts Emulsion A prepared previously 10 parts Microcrystalline wax 5 parts (EMUSTAR-42X manufactured by Nippon Wax Co., Ltd.)
Water 5 parts Compound X (crosslinking agent) 0.5 parts Adjust pH to 8 with NaOH

Further, a receiving layer was formed by coating and drying the receiving layer coating liquid-1 having the following composition on the heat insulating layer so that the solid content coating amount was 5 g / m ² . These steps may be simultaneous multilayer coating.

(1-2) Preparation of Samples 102 to 107 Samples 102 to 107 were prepared in the same manner as the sample 101 except that the receiving layer polymer latex in the sample 101 was changed to that shown in Table 1.

As a support, synthetic paper YUPO (manufactured by FGS-200 YUPO Corporation) was changed, and the above receiving layer coating solution-1 was coated and dried so that the solid content coating amount was 5 g / m ^2. Obtained.

(Image formation)
The image receiving sheets of Samples 101 to 108 were processed so that they could be loaded into a sublimation printer ASK2000 (trade name) manufactured by Fuji Photo Film Co., Ltd., and an image was output. At this time, it took 13 seconds to output one L-size print. The formed image-receiving sheet was evaluated for image density and image quality as follows, and the results are shown in Table 2.

[Image density]
The density (Dmax) of yellow (Y), magenta (M), and cyan (C) in the black image obtained under the above conditions was measured with a Photographic Densitometer (manufactured by X-Rite Incorporated).

[Light fastness evaluation]
The concentration was measured before and after exposure to 100,000 lux Xe light for 14 days. The relative residual ratio of each hue after storage at a reflection density of 1.0 for yellow (Y), magenta (M), and cyan (C) was calculated by averaging.

[image quality]
An image obtained by printing an image under the above-mentioned conditions was observed with a magnifying glass at a visual density of about 0.5, and was evaluated by white spots that are image defects.
○: No white spots and excellent image quality △: Some white spots but almost no practical problem ×: Many white spots and inferior practicality

  From the results of Table 2, it was found that the samples of the present invention can provide high-quality images with high density of Y, M, and C in black images, good light fastness and few image failures. Compared with these, the sample 106 having a vinyl chloride latex particle size of 1.0 μm or more has a high Y concentration, but the M and C concentrations are relatively low, and the balance is poor and the image is not good. Is appropriate. Also, there are many image failures, and the image quality has not reached a sufficient level. In addition, the sample 108 using synthetic paper (YUPO) including a void structure as a support instead of the heat insulating layer made of a hollow polymer generally has a low reached maximum density and cannot be said to be a good image. Sample 107 using polyester as the receiving layer polymer is also a result of relatively low M and C concentrations and insufficient light fastness.

Claims (6)

  Polymer latex comprising a heat insulating layer containing at least a water-soluble polymer and a foamed hollow polymer on at least one surface of a sheet-like support mainly composed of cellulose pulp, and a copolymer containing a repeating unit obtained from vinyl chloride A heat-sensitive transfer image-receiving sheet, wherein a receiving layer containing a polymer latex having an average particle diameter of less than 1.0 μm is sequentially laminated.   The thermal transfer image receiving apparatus according to claim 1, wherein the heat insulating layer is formed of a heat insulating layer coating material having a density ratio of coating solution / calculated density of the coating solution of 0.7 to 1.2. Sheet.   The thermal transfer image-receiving sheet according to claim 1 or 2, wherein the hollow polymer has an average particle size of 0.5 to 10 µm.   The heat-sensitive transfer image-receiving sheet according to any one of claims 1 to 3, wherein the hollow polymer contained in the heat insulating layer has a hollow ratio of 75 to 95%.   The heat-sensitive transfer image-receiving sheet according to any one of claims 1 to 4, wherein the heat-insulating layer has a thickness of 10 to 110 µm. The thermal transfer image-receiving sheet according to any one of claims 1 to 5, wherein a mass ratio of the hollow polymer to the total solid mass of the heat insulating layer coating liquid is 30 to 75%.