JP2007237522A - Thermal transfer receiving sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiving sheet which has a back coating layer excellent in adhesion properties and is free from peeling of the back coating layer, powdering of particles or the like, etc. and which has a function of sufficiently preventing blocking of the back layer and a receiving layer side, causes no image defect such as a void or the like on the occasion when a color image is formed, and enables attainment of excellent image quality and printing density. <P>SOLUTION: This thermal transfer receiving sheet has a sheetlike substrate, the image receiving layer formed on one side of the sheetlike substrate and constituted mainly of a dyeing resin and the back coating layer formed on the other side of the sheetlike substrate. The back coating layer contains a silanol modified polyvinyl alcohol resin as an adhesive resin. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermal transfer receiving sheet (hereinafter simply referred to as a receiving sheet). More specifically, the present invention relates to a receiving sheet that exhibits good image quality and print density without image defects such as white spots when a color image is formed using a thermal transfer printer.

  A high-quality color hard copy printing system using a dye thermal transfer system includes a printer, a thermal transfer sheet (hereinafter simply referred to as an ink ribbon), and a receiving sheet. As a general method for forming a color image on a receiving sheet, an ink ribbon in which a color material layer composed of three or four colors of yellow, magenta, cyan, and black as necessary is provided in a surface sequential manner, and an image A receiving sheet provided with a receiving layer (hereinafter simply referred to as a receiving layer) is brought into close contact, and is passed between a heating device pressed with a constant pressure and a platen roller. At that time, the heat generating portion of the heating device is selectively heated according to the image information, and the dye contained in the color material layer of the ink ribbon is transferred to the receiving layer of the receiving sheet to form an image. The ink ribbon is provided with three or four color material layers in a surface sequence, and different colors are sequentially transferred to the same position on the receiving sheet in three or four times, and each color is superimposed. As a result, a color image is formed. In such a dye thermal transfer type printer, the receiving sheet is generally supplied in a sheet state.

  In general, the receiving sheet is formed on one side of the sheet-like support and the sheet-like support, and is formed on the other side of the sheet-like support, and a receiving layer excellent in the dyeing property of the dye transferred from the ink ribbon. It is formed from the back surface layer provided with the blocking prevention property with a receiving layer.

  In the manufacturing process, the receiving sheet can be stacked and subjected to a load at a high temperature in a state where the receiving layer surface and the back surface layer are in contact with each other, such as coating and drying the receiving layer coating material and the back layer coating material, and taking up and storing in a roll. It is normal. The receiving layer is required to easily transfer the color material layer of the ink ribbon, and is mainly composed of a thermoplastic resin. For this reason, the back surface layer is required to have a function of preventing sticking to the receiving layer (so-called blocking). When blocking occurs, the glossiness of the surface of the receiving layer is lowered, so that the appearance as a receiving sheet is impaired and the commercial value is lowered. Alternatively, since the smoothness of the receiving layer surface is lowered, the image quality is deteriorated when forming a color image.

  Further, for the purpose of preventing blocking between the receiving layer surface and the back layer surface of the thermal transfer receiving paper, for example, a method of providing a “surface layer” made of an acrylic resin on the surface of the receiving layer is disclosed (for example, patents). Reference 1). However, when a “surface layer” is provided on the surface of the receiving layer, there is a problem that the dye cannot be sufficiently transferred from the colorant layer of the ink ribbon to the receiving sheet, and a clear image cannot be obtained.

  In addition, a back layer containing microsilica and a thermoplastic resin in the first layer, and a back layer containing cellulose acetate in the second layer and a back layer containing a nylon filler are disclosed (for example, see Patent Document 2). Examples of the resin include polyurethane resin, polyester resin, polyvinyl acetate resin, polyvinyl acetal resin, polyvinyl butyral resin, cellulose plastic, polyolefin resin, acrylic resin, and the like. Further, a back layer containing a heat resistant resin and an abrasive is disclosed (for example, see Patent Document 3). As the heat resistant resin, an acrylic resin, an epoxy resin, a polyimide resin, a silicone resin, and an acrylic-silicone resin are disclosed. Fluorine-based resin and the like are exemplified. However, even if only the resin as described above is used for the back layer, the actual situation is that the anti-blocking property with respect to the receiving layer surface and other general required qualities are not sufficiently satisfied.

  By including microsilica or an abrasive in the back layer, the contact area between the receiving layer and the back layer is reduced, and a certain degree of blocking prevention effect can be expected. However, when microsilica or abrasives fall off from the back layer (so-called powder fall) and move to the receiving layer surface, and the migration of the dye is hindered at the powder adhering part, or when the back surface layer of microsilica or abrasive is on the receiving layer surface When the shape is transferred to form a recess on the surface of the receiving layer, the dye may be difficult to move to the surface of the receiving layer due to the shape, and as a result, there is a problem that a white spot phenomenon occurs in a color image.

JP 2003-94843 A (2nd page) JP-A-8-230337 (page 2-3) Japanese Patent Laid-Open No. 5-116472 (page 2-3)

  The present invention has been made in view of the circumstances as described above, and the back surface coating layer of the receiving sheet (hereinafter simply referred to as the back surface layer) has good adhesiveness, There is no powder fall off of fine particles, etc., and it has a function to sufficiently prevent blocking between the back layer and the receiving layer surface, and there is no image defect such as white spots when forming a color image, and good image quality and printing It is an object of the present invention to provide a receiving sheet capable of obtaining a concentration.

The present invention includes the following inventions.
(1) A sheet-shaped support, an image receiving layer mainly composed of a dye-dyeable resin formed on one surface of the sheet-shaped support, and formed on the other surface of the sheet-shaped support. A thermal transfer receiving sheet having a back coating layer, wherein the back coating layer contains a silanol-modified polyvinyl alcohol resin as an adhesive resin.
(2) The thermal transfer receiving sheet according to item (1), wherein the back surface coating layer further contains a polyacrylate resin as an adhesive resin.
(3) The thermal transfer receiving sheet according to (1) or (2), wherein the back coating layer contains nylon resin fine particles having an average particle size of 20 μm or less.

  The receiving sheet of the present invention has good adhesion of the back layer, no peeling of the back layer, no powder falling off of fine particles, etc., and sufficient blocking prevention even if the back layer is left in contact with the receiving layer In particular, when a color image is formed, there are no image defects such as white spots, and a good image quality and a sufficient print density.

  In the receiving sheet of the present invention, at least a sheet-like support and a receiving layer for receiving a dye are laminated on one side of the sheet-like support, and further on the side of the sheet-like support on which the receiving layer is not provided. A receiving sheet having a configuration in which a back layer is laminated. Hereinafter, each layer constituting the receiving sheet will be described in detail.

(Back layer)
In the back layer of the present invention, silanol-modified polyvinyl alcohol resin is used for the back layer. The silanol-modified polyvinyl alcohol resin is excellent in heat resistance and can prevent blocking even if it contacts a receiving layer surface containing a thermoplastic resin at a high temperature. Silanol-modified polyvinyl alcohol resin has a great effect of improving the adhesive strength with a support as an adhesive resin.

  Furthermore, when various fine particles are added to the back surface layer for the purpose of preventing blocking or the like, the adhesiveness with the fine particles is good, and “powder off” in which the fine particles fall off from the back surface layer can be prevented. It is considered that high adhesiveness can be obtained by silanol groups possessed by the silanol-modified polyvinyl alcohol resin by hydrogen bonding or dehydration condensation with hydroxyl groups present on the surface of fine particles contained in the receiving sheet support or the back layer.

The silanol-modified polyvinyl alcohol resin used in the present invention can be produced by a conventionally known synthesis method, and a copolymerization of vinyltrimethoxysilane and vinyl acetate in methanol or the like, followed by methanolysis using sodium hydroxide as a catalyst, The target polymer can be obtained by saponifying vinyl acetate. Examples of commercially available products include R-1130, R-2105, R-2130 (manufactured by Kuraray). The silanol-modified polyvinyl alcohol resin of the present invention preferably has a saponification degree of 85% or more and a silanol group content in the molecule of 0.05 to 3 mol% as a monomer unit.
In the back layer of the present invention, the silanol-modified polyvinyl alcohol resin is preferably contained in an amount of 2% by mass or more of the total solid content of the back layer, and more preferably 4 to 80% by mass in order to obtain sufficient adhesive strength. If it is less than 2% by mass, peeling of the back surface layer, falling off of fine particles, etc., and blocking between the back surface layer and the receiving layer may occur.

  As the adhesive resin used in the back layer of the present invention, in addition to the silanol-modified polyvinyl alcohol resin, an adhesive resin generally used within a range not impairing the effects of the present invention can be used together. Polyvinyl alcohol resins such as saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, polyethylene oxide resin, polyethylene glycol resin, poly (meth) acrylic acid resin, poly (meth) acrylic acid Water-soluble resins such as ester resins and starches, acrylic resins such as polyacrylates, styrene-butadiene copolymer resins, urethane resins, polyvinyl acetal resins, polyvinyl butyral resins, polyester resins, and epoxy resins Resin, melamine resin, phenol resin, phenoxy resin, organic solvent-soluble resin such as cellulose derivative resin, mixed solvent-soluble resin consisting of water and organic solvent such as polyvinyl acetal resin, acrylic resin are used. Two or more kinds may be used in combination. Also, reaction cured products of these resins can be used.

  As the back surface layer adhesive resin, acrylic resins such as polyacrylic acid ester, polyvinyl acetal resin, polyvinyl butyral resin, polyvinyl alcohol resin, starch, phenoxy resin and the like are preferably used in combination. Among them, polyacrylate resin is more preferably used in combination, and commercially available products include, for example, Jurimer FC80 (manufactured by Nippon Pure Chemicals), Polysol AM2250 (manufactured by Showa Kogyo), Rikabond SAR615A (manufactured by Chuo Rika), Barrier Star B1000 (Mitsui Chemicals). Manufactured) and the like. Furthermore, a polyacrylic ester resin having a carboxyl group is preferably used in combination, and the stability during preparation of the coating liquid, the uniformity of the formed coating film, water resistance, and the like are also good. As a commercial item, Jurimer AT510,515,613 (made by Nippon Pure Chemical) etc. are mentioned.

As for the compounding quantity of adhesive resin, 50 mass% or more is preferable with respect to the total solid of a back surface layer. If the blending amount is less than 50% by mass, the adhesiveness of the back layer to the support may be insufficient, although it depends on the type of adhesive resin.
The blending amount of the silanol-modified polyvinyl alcohol resin is preferably 5% by mass or more with respect to the total adhesive resin component for the back layer, and if it is less than 5% by mass, the adhesion with the substrate may be insufficient. May cause peeling of fine particles, powder falling off of fine particles, etc., and blocking between the back surface layer and the receiving layer.

  The back layer of the present invention can contain various known fine particles for the purpose of preventing blocking. As fine particles, inorganic fine particles and / or organic fine particles may be used. Examples of inorganic fine particles include metals such as aluminum, iron and copper, metal oxides such as silica, titanium oxide, zinc oxide and alumina, inorganic salts such as calcium carbonate, barium sulfate and calcium sulfate, kaolin, calcined kaolin, clay, Examples include minerals such as talc and diatomaceous earth. As the organic fine particles, organic fine particles such as nylon resin, styrene resin, acrylic resin, urea resin, melamine resin, benzoguanamine resin, phenol resin, silicone resin, and fluorine resin can be arbitrarily used together.

  In the present invention, among these particles, nylon resin fine particles are preferably used because of their moderately low hardness and excellent adhesion to silanol-modified polyvinyl alcohol resin. For example, nylon 12, nylon 6, nylon 6, 6 and the like. The resin fine particle which consists of is mentioned. As the kind of nylon resin fine particles, nylon 12 resin fine particles are more preferable because they are superior in water resistance and less change in properties due to water absorption than nylon 6, nylon 6/6 resin fine particles.

  The nylon resin fine particles preferably contain nylon resin fine particles (also referred to as nylon filler) having an average particle diameter of 20 μm or less and a coefficient of variation of the average particle diameter of 5% or less. In the present invention, the coefficient of variation CV can be expressed by CV = σ / φ (σ: standard deviation of particle diameter of nylon resin fine particles, φ: average particle diameter of nylon resin fine particles). Here, the coefficient of variation is the ratio of the standard deviation to the average particle diameter, and in the present invention is a value representing the degree of variation in the particle diameter of the nylon resin fine particles. Note that the coefficient of variation is corrected so as to be independent of the average value by dividing by the average value so that the standard deviations of groups with different average values can be directly compared.

In the present invention, the average particle size of the nylon resin fine particles is preferably 20 μm or less, more preferably 1 to 10 μm. The coefficient of variation is preferably 5% or less. When the average particle diameter of the nylon resin particles exceeds 20 μm, or when the coefficient of variation exceeds 5%, the protrusion of the nylon resin particles from the surface of the back surface layer may become large, and the back surface layer and the receiving layer are in strong contact. In this case, the receiving layer may become moldy or white spots may occur in the printed image. Further, when the receiving sheet is rubbed, the nylon resin fine particles may fall off. On the other hand, when the average particle size is too small, the anti-blocking effect may not be sufficiently obtained.
As a particle diameter measuring method of nylon resin fine particles, the average particle diameter and the standard deviation of the particle diameter can be measured using a general particle diameter measuring apparatus, for example, a laser diffraction type particle size distribution measuring device (trade name: SALD2000, manufactured by Shimadzu Corporation) can be used.

  As for the compounding quantity of nylon resin microparticles | fine-particles, 1-25 mass% is preferable with respect to the total solid of a back surface layer. If the blending amount is less than 1% by mass, the anti-blocking effect becomes insufficient, and the back surface layer and the receiving layer may stick. On the other hand, when the blending amount exceeds 25% by mass, when the back layer coating material is applied with a coater, streaks due to the precipitation of nylon resin fine particles are likely to occur, and problems such as deterioration of the coating surface may occur. is there.

In the present invention, the solid coating amount of the back layer is preferably in the range of 0.5 to 10 g / ^{m 2,} more preferably from 1 to 7 g / ^{m 2.} Incidentally, when the solid content coating amount is less than 0.5 g / m ² , the back surface layer cannot completely cover the surface of the sheet-like support, and a coating film defect may occur. On the other hand, when the solid content coating amount exceeds 10 g / m ² , the effect is saturated, and the cost tends to increase, resulting in an economical disadvantage.

  Furthermore, in the coating liquid for forming the back layer, various additives such as an antistatic agent, a lubricant, a release agent, an antifoaming agent, a dispersant, a resin crosslinking agent, a colored dye, and a fluorescent dye are used as necessary. Fluorescent pigments, ultraviolet absorbers and the like may be appropriately selected and used.

  The back surface layer of the present invention may contain an antistatic agent in order to prevent troubles in feeding and discharging due to electrostatic charging and troubles in running. Antistatic agents include anionic, cationic, nonionic, and amphoteric surfactants, and polymer resin-type conductive agents include anionic, cationic, nonionic conductive resins, and electronically conductive inorganic materials. A fine powder, a carbon fine powder, and the like can be mentioned, and a polymer resin type conductive agent is preferably used from the standpoint of maintaining the antistatic effect for a long period of time and the hue of the antistatic agent.

  As the polymer resin type conductive agent, a cation type conductive resin is well known, but an anionic type conductive resin is preferably used because of its high price and generation of amine odor during thermal decomposition. Examples of anionic conductive resins include polymers containing carboxyl groups, sulfonic acid groups, etc., such as polyacrylic acid, polymethacrylic acid, vinyl chloride-maleic acid mono (2-ethylhexyl) copolymer, polystyrene sulfonic acid, and the like. And the like, in which a part or all of the functional groups corresponding to each of them is an alkali metal salt, alkaline earth metal salt, transition metal salt, or the like. Of these, polyacrylic acid, polymethacrylic acid, and alkali metal salts or alkaline earth metal salts of polystyrene sulfonic acid are preferable. In particular, sodium salt of polystyrene sulfonic acid has an antistatic function, solubility, and other used in the back layer. Since it is excellent in compatibility with adhesive resin, it is especially preferable.

  The blending amount of the antistatic agent is preferably 3 to 25% by mass, more preferably 5 to 20% by mass with respect to the total solid content of the back surface layer. Incidentally, if the blending amount is less than 3% by mass, the surface electrical resistance on the back side of the receiving sheet becomes high, and a sufficient antistatic effect cannot be obtained, so that the paper feeding and discharging performance of the printer and the running performance of the receiving sheet may be inferior. . On the other hand, if the blending amount exceeds 25% by mass, the strength of the white paper coating film on the back surface layer at high temperature and high humidity may decrease.

  In the back layer of the present invention, a lubricant such as a higher fatty acid salt may be added as a release agent. The higher fatty acid salt that can be used is usually a saturated or unsaturated fatty acid having 12 to 24 carbon atoms, preferably 16 to 20 carbon atoms. Specifically, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, Linoleic acid, oleic acid and the like can be mentioned, and preferred salts of such higher fatty acids include metal salts such as calcium salts, magnesium salts, aluminum salts, zinc salts and barium salts. Particularly preferred are metal stearates, such as zinc stearate, calcium stearate, barium stearate and the like.

  3-50 mass% is preferable with respect to the total solid of a back surface layer, and, as for the compounding quantity of lubricants, such as higher fatty acid salt, More preferably, it is 5-45 mass%. Incidentally, when the blending amount of the lubricant is less than 3% by mass, the back layer and the ink ribbon tend to be fused when printing with the receiving sheet turned upside down, and so-called back print suitability may be deteriorated. On the other hand, if the blending amount exceeds 50% by mass, the slipping property of the back surface layer becomes excessive, and there is a possibility that the writing property and the printability by the ink jet printer may be deteriorated, and the stamp sticking property may be insufficient.

(Sheet support)
Examples of the sheet-like support used in the present invention include paper base materials such as coated paper, art paper, and high-quality paper, resin-coated paper obtained by coating a paper base with a thermoplastic resin such as polyethylene, and heat such as polyethylene and polypropylene. Laminated paper obtained by extruding and laminating a plastic resin to a paper base material, thermoplastic film such as polyethylene terephthalate, nylon, polyolefin (for example, polypropylene, polyethylene, a mixture of polyethylene and polypropylene), or thermoplastic resin such as polyolefin resin, polyethylene terephthalate resin Examples include porous single-layer or multi-layer films in which voids are formed by uniaxially and / or biaxially stretching a molten resin composition composed mainly of a resin and a void forming agent (inorganic pigment or organic fine particles). Is done. Furthermore, not only the above-mentioned material is used alone, but also a known method such as a dry laminating method, a wet laminating method, a melt laminating method, etc. can be used to laminate two or more of the above materials into a multilayer structure, The combination is not limited.

In addition, coated paper provided with a coating layer mainly composed of hollow particles and a binder on at least one surface of a paper substrate can also be used as a support. The back surface coating layer containing the silanol-modified polyvinyl alcohol resin of the present invention is a preferable embodiment because an excellent effect is obtained particularly in a sheet-like support including a paper base material mainly composed of cellulose pulp.
Further, an adhesive sheet having a structure such as a so-called label type (also referred to as a sticker or a seal type) in which the above-described sheet-like support and a base material coated with a release agent are laminated via an adhesive. A structured support can also be used.

  The thickness of the sheet-like support is preferably 100 to 300 μm. Incidentally, if the thickness is less than 100 μm, the mechanical strength is insufficient, and the rigidity of the receiving sheet obtained therefrom and the repulsive force against deformation are insufficient, so that the curling of the receiving sheet generated at the time of printing is sufficient. There are some cases that cannot be prevented. In addition, if the thickness exceeds 300 μm, the thickness of the receiving sheet obtained becomes excessive, which causes a decrease in the number of receiving sheets accommodated in the printer or an increase in the volume of the printer, making it difficult to make the printer compact. May cause problems.

(Middle layer)
The receiving sheet of the present invention includes an intermediate layer between the sheet-like support and the receiving layer for the purpose of improving the adhesion between the sheet-like support and the receiving layer, improving the antistatic property of the receiving sheet, improving the barrier property, etc. May be provided. As the resin used for forming the intermediate layer, various hydrophilic resins and hydrophobic resins can be used. For example, vinyl polymers such as polyvinyl alcohol and polyvinyl pyrrolidone and derivatives thereof, polyacrylamide, polydimethylacrylamide, poly Acrylic acid or salts thereof, polymers containing acrylic groups such as polyacrylic acid esters, polymers containing methacrylic groups such as polymethacrylic acid and polymethacrylic acid esters, polyester resins, polyurethane resins, starch, modified starch, carboxy Resins such as cellulose derivatives such as methylcellulose can be used. Further, known antistatic agents and crosslinking agents can be used alone or in combination with the above resins.

The solid coating amount of the intermediate layer is preferably in the range of 0.2 to 5 g / m ² , more preferably in the range of 0.5 to 3 g / m ² . Incidentally, if the solid content coating amount is less than 0.2 g / m ² , the effect of improving the adhesion as the intermediate layer is small, while if it exceeds 5 g / m ² , the operability may be lowered.

(Receptive layer)
In the receiving sheet of the present invention, the receiving layer provided on one surface of the sheet-like support is formed mainly of a dye dyeable resin capable of dyeing a dye migrating from the ink ribbon. Examples of such dye-dyeing resins include polyester resins, vinyl chloride-vinyl acetate copolymer resins, polyvinyl acetal resins, acrylic resins, polycarbonate resins, and cellulose derivative resins.

The solid content coating amount of the receiving layer is adjusted in the range of 1 to 12 g / m ² , preferably 3 to 10 g / m ² . Incidentally, if the solid coating amount is less than 1 g / m ² , the receiving layer cannot completely cover the surface of the support, resulting in deterioration of the image quality, and the receiving layer and the ink ribbon are bonded by heating the thermal head. May cause fusing troubles. On the other hand, when the solid content coating amount exceeds 12 g / m ² , not only is the effect saturated and uneconomical, but also the strength of the receptor layer is insufficient, or the thickness of the receptor layer is increased and the sheet-like support is increased. The heat insulation effect is not sufficiently exhibited, and the image density may be lowered.

  In order to prevent fusion between the receiving layer and the ink ribbon at the time of thermal printing with a thermal head, it is preferable to add a crosslinking agent, a lubricant, a release agent, or the like of the dye dyeable resin to the receiving layer. If necessary, other additives such as colored pigments, colored dyes, fluorescent pigments, fluorescent dyes, plasticizers, antioxidants, white pigments, ultraviolet absorbers, and light stabilizers may be added. These additives may be applied by mixing with the main component of the receiving layer, or may be applied on and / or below the receiving layer as a separate coating layer.

  The intermediate layer, the receiving layer, the back surface layer, and other coating layers of the receiving sheet of the present invention are a bar coater, a gravure coater, a comma coater, a blade coater, an air knife coater, a gate roll coater, a die coater, a curtain coater, and It can be formed by coating and drying with a known coater such as a slide bead coater.

  The present invention will be described in detail by the following examples and comparative examples, but the scope of the present invention is not limited thereto. In Examples and Comparative Examples, unless otherwise specified, “%” and “parts” indicate “mass%” and “parts by mass” of solids, except for those relating to solvents.

Example 1
Biaxially stretched porous multilayer structure film (trade name: YUPO FPG60, manufactured by YUPO Corporation) with a biaxially stretched structure containing inorganic pigment as a main component on both sides of a polyethylene terephthalate (PET) film having a thickness of 50 μm The sheet-like support was obtained by pasting together by a dry laminating method using a polyester adhesive.

On one surface of the support, the following receiving layer coating solution-1 was coated with a gravure coater so that the solid coating amount was 5 g / m ² and dried to form a receiving layer. Thereafter, the receptor layer was cross-linked by holding it at 50 ° C. for 3 days.
Receiving layer coating solution-1
Polyester resin (trade name: Byron 200, manufactured by Toyobo) 100 parts silicone oil (trade name: KF393, manufactured by Shin-Etsu Chemical Co., Ltd.) 3 parts isocyanate compound (trade name: Takenate D110N, manufactured by Mitsui Takeda Chemical Co., Ltd.) 5 parts Toluene / Methyl ethyl ketone = 1 / 400 (mass ratio) liquid mixture 400 parts

Next, on the opposite surface of the sheet-like support provided with the receiving layer, the following back surface layer coating solution-1 is applied with a gravure coater so that the solid content coating amount is 3 g / m ² and dried. A back layer was formed.
Back layer coating solution-1
Silanol-modified polyvinyl alcohol resin (trade name: R2105, saponification degree 98%,
Degree of polymerization: 700, manufactured by Kuraray) 70 parts polyacrylic ester resin (trade name: Polysol AM2250,
10 parts zinc stearate (trade name: KW509, manufactured by Kyoyo Chemical) 10 parts anionic conductive resin (trade name: Chemistat SA-9,
Main component: Polystyrene sulfonate sodium, manufactured by Sanyo Chemical Co., Ltd.) 10 parts Water / isopropyl alcohol = 2/3 (mass ratio) mixed solution 500 parts

Example 2
A receiving sheet was obtained in the same manner as in Example 1 except that the following back surface layer coating liquid-2 was used instead of the back surface layer coating liquid-1.
Back layer coating liquid-2
Silanol-modified polyvinyl alcohol resin (trade name: R1130, saponification degree 98%,
Degree of polymerization: 1700, manufactured by Kuraray) 5 parts fully saponified polyvinyl alcohol resin (trade name: PVA105, manufactured by Kuraray) 20 parts polyacrylic ester resin (trade name: Jurimer AT613, manufactured by Nippon Pure Chemical,
40 parts zinc stearate (trade name: KW509, manufactured by Kyoyo Chemical) 20 parts anionic conductive resin (trade name: Chemistat SA-9, having a carboxyl group in the molecule)
Main component: Polystyrene sulfonate sodium, manufactured by Sanyo Chemical Co., Ltd.) 15 parts Water / isopropyl alcohol = 2/3 (mass ratio) mixed solution 500 parts

Example 3
(Formation of intermediate layer and barrier layer)
As a sheet-like support, art paper (trade name: OK Kanto N, 174.4 g / m ² , made by Oji Paper Co., Ltd.) having a thickness of 150 μm is used, and an intermediate layer coating liquid-1 having the following composition is applied on one side thereof. The intermediate layer was formed by coating and drying so that the film thickness after drying was 51 μm. Next, the barrier layer coating liquid-1 having the following composition was coated on the intermediate layer so as to have a solid content coating amount of 2 g / m ² and dried to form a barrier layer.
Intermediate layer coating solution-1
Pre-foamed hollow particles (average particle size 3.2 μm, volume hollow ratio 76%) made of a copolymer mainly composed of acrylonitrile and methacrylonitrile 50 parts partially saponified polyvinyl alcohol resin (trade name: PVA205, manufactured by Kuraray Co., Ltd.) 10 Partially modified styrene-butadiene latex (trade name: PT1004, manufactured by Zeon Corporation) 40 parts Water 250 parts
Coating liquid for barrier layer-1
Swellable inorganic layered compound (sodium 4 silicon mica, particle average major axis 6.3 μm,
(Aspect ratio 2,700) 10 parts Fully saponified polyvinyl alcohol resin (trade name: PVA105, manufactured by Kuraray) 90 parts Water 1100 parts

On one surface of the support, the receiving layer coating solution-1 (prepared in Example 1) was applied with a gravure coater so that the solid content coating amount was 4 g / m ² , dried and received. A layer was formed. Thereafter, the receptor layer was cross-linked by holding it at 50 ° C. for 3 days. Next, on the opposite surface of the sheet-like support provided with the receiving layer, the back surface layer coating liquid-2 (prepared in Example 2) is applied with a gravure coater so that the solid content coating amount is 3 g / m ^2. The back layer was formed by coating and drying.

Example 4
A receiving sheet was obtained in the same manner as in Example 3, except that the following back surface layer coating liquid-3 was used instead of back surface layer coating liquid-2 (prepared in Example 2).
Back layer coating solution-3
Silanol-modified polyvinyl alcohol resin (trade name: R1130, saponification degree 98%,
Degree of polymerization: 1700, manufactured by Kuraray Co., Ltd. 40 parts polyacrylic ester resin (trade name: Jurimer AT613, manufactured by Nippon Pure Chemical) 40 parts nylon filler (trade name: 2001 EXDNAT1, manufactured by Elfalt Chem,
Average particle diameter 10μ, coefficient of variation 4.5%) 3 parts anionic conductive resin (trade name: Chemista SA-9,
Main component: Polystyrene sulfonate sodium, manufactured by Sanyo Chemical Co., Ltd.) 15 parts Water / isopropyl alcohol = 2/3 (mass ratio) mixed solution 500 parts

Comparative Example 1
Except for using a polyvinyl acetal resin (trade name: ESREC KX-1, manufactured by Sekisui Chemical Co., Ltd.) in place of the silanol-modified polyvinyl alcohol resin in the preparation of the back layer coating solution-3 (prepared in Example 4). In the same manner as in Example 4, a receiving sheet was obtained.

Comparative Example 2
In the preparation of the backside layer coating liquid-3 (prepared in Example 4), the same procedure as in Example 4 was performed except that a polyvinyl alcohol resin (trade name: PVA105, manufactured by Kuraray Co., Ltd.) was used instead of the silanol-modified polyvinyl alcohol resin. A receiving sheet was obtained.

Quality Evaluation Regarding the receiving sheets obtained in Examples 1 to 4 and Comparative Examples 1 and 2, the following items were evaluated for quality and the results are shown in Table 1.

[Evaluation of Adhesiveness of Receiving Sheet Back Layer]
As a sample for evaluating the adhesiveness between the substrate and the back surface layer in the receiving sheet, a strip-shaped receiving sheet having a width of 18 mm and a length of 170 mm is cut and prepared, and a receiving sheet sample is prepared using a double-sided adhesive tape. The receiving layer side of was fixed on a glass plate. Next, a commercially available adhesive tape (trade name: cello tape (registered trademark), manufactured by Nichiban Co., Ltd., tape width: 18 mm) is adhered onto the back surface layer of the fixed strip-shaped receiving sheet sample, and the adhesive tape is peeled 180 degrees. Regarding the adhesion between the base material and the back surface layer, the occurrence of peeling of the back surface layer or powder falling of the fine particle component contained in the back surface layer was visually evaluated.
Adhesive with excellent adhesion with no peeling of the base material and back surface layer and no adhesion, ○ ○ with adhesion and slight peeling of the base material and back surface layer but no problem in practical use Inferior properties were shown as x when peeling between the base material and the back surface layer or occurrence of powder falling off of fine particle components was conspicuous and impractical.

[Blocking test]
The receiving sheet is stacked on the receiving layer so that the back surface layer is in contact, and a weight is placed so that the load is 800 g / cm ^2, and the receiving sheet is treated in a dryer at 50 ° C. for 3 days. The receptor layer and the back layer were peeled off slowly, and blocking was evaluated by the appearance of the superposed surface and the resistance when peeling off.
There is no resistance when the receiving layer surface and the back surface are peeled off, and there is no appearance abnormality on the peeled surface. There is very little resistance when peeling, but there is almost no trace on the appearance of the peeled surface. When the material was not practically problematic, the resistance was felt when it was peeled off, and a trace remained on the peeled surface.

[Print quality] (Print density, image uniformity)
Print quality was evaluated using the receiving sheet after the blocking test. Using a commercially available thermal transfer video printer (trade name: UP-DR100, manufactured by Sony Corporation), an ink layer containing yellow, magenta, and cyan sublimation dyes with binders on a 6 μm thick polyester film is provided. Each color ink layer of the ink ribbon is brought into contact with the receiving sheet in sequence, and heat is transferred stepwise by a thermal head to thermally transfer a predetermined image to the receiving sheet. Overlaid images were printed.

(Print density)
About the obtained recorded image, the reflection density was measured using the Macbeth reflection densitometer (brand name: RD-914, product made by Kollmorgen). The density of the high gradation portion corresponding to the 15th step from the lowest applied energy is displayed in Table 1 as the print density. If the print density is 1.70 or more, it is judged that there is sufficient commercial value.

(Image uniformity)
Further, as an evaluation of the uniformity of the recorded image, the presence / absence of a print defect such as a white spot was visually observed in a gradation portion corresponding to an optical density (black) of 0.3.
No white spots etc. and excellent image uniformity ◎, white spots slightly, but no problems in practical use ○, print defects such as white spots are conspicuous and those that are not practical use × displayed.

The receiving sheet of the present invention has good adhesion to the back surface layer, no powder fall off, etc., and has sufficient anti-blocking properties even when the back layer is left in contact with the receiving layer, and has excellent print quality. It can be used as a receiving sheet having high practical value.

Claims (3)

  A sheet-like support, an image receiving layer mainly composed of a dye-dyeable resin formed on one surface of the sheet-like support, and a back surface coating formed on the other surface of the sheet-like support A thermal transfer receiving sheet, wherein the back coating layer contains a silanol-modified polyvinyl alcohol resin as an adhesive resin.   The thermal transfer receiving sheet according to claim 1, wherein the back coating layer further contains a polyacrylate resin as an adhesive. The thermal transfer receiving sheet according to claim 1, wherein the back coating layer contains nylon resin fine particles having an average particle diameter of 20 μm or less.