JP4373201B2 - Thermal transfer image-receiving sheet and method for producing the same - Google Patents

Description

  The present invention relates to a thermal transfer image-receiving sheet used in superposition with a thermal transfer sheet for sublimation transfer, and a method for producing the same. Specifically, the image-receiving sheet can be widely used in the field of various color printers such as video printers, and has a print density. The present invention relates to a high-productivity thermal transfer image-receiving sheet and a method for producing the same.

  Conventionally, various thermal transfer methods are known. Among them, a sublimation dye is used as a recording material, and this is supported on a substrate sheet such as paper or plastic film to form a thermal transfer sheet, which can be dyed with a sublimation dye. There have been proposed methods for forming various full-color images on a thermal transfer image-receiving sheet, for example, a thermal transfer image-receiving sheet provided with a dye-receiving layer on the surface of paper or plastic film. Since this method uses a sublimation dye as a color material, the density gradation can be freely adjusted, and a full color image of an original can be expressed. In addition, the image formed with the dye is very clear and excellent in transparency, so it is excellent in intermediate color reproducibility and gradation reproducibility, and can form high-quality images comparable to silver salt photographs. Is possible.

  In order to form a high-quality print image on an image receiving sheet at high speed by such a sublimation type thermal transfer printer, an image receiving layer mainly composed of a dye-dyeable resin is provided on a base material. If paper such as coated paper or art paper is used as the base material, the thermal conductivity is relatively high, and thus there is a drawback that the sensitivity for receiving the dye for image formation is low.

  Therefore, as shown in Patent Document 1, it is known to use a biaxially stretched film having a void as a main component of a thermoplastic resin such as polyolefin as a base material of an image receiving sheet. An image receiving sheet based on such a film has a uniform thickness, is flexible, and has a low thermal conductivity compared to paper made of cellulose fibers, so that a uniform and high density image can be obtained. There is.

  However, when such a biaxially stretched film is used as the substrate of the image receiving sheet, the residual stress during stretching is relaxed by the heat during printing, and heat shrinks in the stretching direction, resulting in curling and wrinkling on the image receiving sheet. Occurred and caused problems such as paper jams when traveling through the printer.

  In order to improve these drawbacks, as disclosed in Patent Document 2, a biaxially stretched film having voids on both sides or one side of a core material having a relatively low thermal shrinkage rate and a core material having a relatively high elastic modulus was laminated and bonded. It is known to use a laminate sheet as a base material for an image receiving sheet. However, a biaxially stretched film having voids has a drawback that it is difficult to control the tension during lamination because of its high stretchability, and the cost is significantly increased.

Japanese Patent Laid-Open No. 5-16539 JP-A-3-268998

  The present invention has the disadvantages of the prior art, that is, a decrease in sensitivity when using pulp paper such as coated paper as a support, and a decrease in transportability when using a void-containing biaxially stretched film. Lamination of a foam film and a core material Solves the shortcomings of productivity reduction and cost increase when using a bonding sheet, is inexpensive, has no uneven density or missing dots, has high performance and can produce high-density, high-resolution images, An object of the present invention is to provide a good thermal transfer image receiving sheet.

The invention according to claim 1 is a thin film gas comprising a thick film gas barrier layer having a thickness of 20 to 50 μm , a heat insulating layer, and an ethylene vinyl alcohol copolymer (EVOH) film having a thickness of 1 to 10 μm on a base sheet. A gist is a thermal transfer image-receiving sheet characterized by sequentially laminating a barrier layer and a dye-receiving layer. The invention according to claim 2 is a thermal transfer image receiving sheet in which a thick film gas barrier layer, a heat insulating layer, a thin film gas barrier layer, and a dye receiving layer having a thickness of 20 to 50 μm are sequentially provided on a base sheet. In this manufacturing method, a thin film gas barrier film made of an ethylene vinyl alcohol copolymer (EVOH) film having a thickness of 1 to 10 μm is used as the thin film gas barrier layer, and a foaming agent or a heat-expandable film is formed on one surface of the film. When providing a resin layer containing microcapsules and laminating the resin layer side of the thin film gas barrier film and the thick film gas barrier film as the thick film gas barrier layer while heating and pressing with a hot roll Then, the resin layer is foamed or expanded to form a heat insulating layer, and then the surface opposite to the surface on which the heat insulating layer of the thin film gas barrier film is provided. A thermal transfer comprising: forming a dye-receiving layer on the opposite side, and then laminating a substrate sheet on the side opposite to the surface on which the heat insulating layer of the thick film gas barrier film is provided. The gist of the manufacturing method of the image receiving sheet.

The invention according to claim 3 is the production of a thermal transfer image receiving sheet in which a thick film gas barrier layer having a thickness of 20 to 50 μm , a heat insulating layer, a thin film gas barrier layer and a dye receiving layer are sequentially provided on a base sheet. In the method, a thin film gas barrier film comprising an ethylene vinyl alcohol copolymer (EVOH) film having a thickness of 1 to 10 μm is used as the thin film gas barrier layer, and a foaming agent or a thermally expandable microcapsule is provided on one side of the film. After the resin layer side of the above thin film gas barrier film and the resin that becomes the thick film gas barrier layer are extruded and laminated, the substrate is heated and pressurized with a hot roll, The above-mentioned foaming agent-containing resin layer is foamed or expanded to form a heat insulating layer, and then the surface of the thin film gas barrier film on which the heat insulating layer is provided The gist is a method for producing a thermal transfer image-receiving sheet, characterized in that a dye-receiving layer is formed on the opposite side of the sheet.

The thermal transfer image-receiving sheet of the present invention comprises a thin film gas barrier comprising a base material sheet comprising a thick film gas barrier layer having a thickness of 20 to 50 μm , a heat insulating layer, and an ethylene vinyl alcohol copolymer (EVOH) film having a thickness of 1 to 10 μm. A thin film gas barrier film made of an ethylene vinyl alcohol copolymer (EVOH) film having a thickness of 1 to 10 μm is used as the thin film gas barrier layer. A resin layer containing a foaming agent or a heat-expandable microcapsule is provided on one side of the film, and the resin film side of the thin film gas barrier film and the thick film gas barrier film as the thick film gas barrier layer are heated. When laminating while heating and pressurizing, the resin layer is foamed or expanded to form a heat insulating layer, and then the thin film gas A dye-receiving layer is formed on the side opposite to the surface on which the heat insulation layer of the rear film is provided, and then the base sheet is laminated to the side opposite to the surface on which the heat insulation layer of the thick film gas barrier film is provided. Are formed by bonding together. As a result, the heat insulation layer has high cushioning properties and heat insulation properties, and the heat insulation layer is sandwiched between gas barrier layers (films) to prevent the gas inside the heat insulation layer from leaking to the outside. The function of the heat insulating layer can be maintained and the function can be prevented from being deteriorated with time. As a result, a thermal transfer image-receiving sheet having a foamed heat insulating layer can be produced efficiently and inexpensively, and there is no uneven density or missing dots, and an excellent thermal transfer image with high density and high resolution can be obtained.

The thermal transfer image-receiving sheet of the present invention has a structure in which a thick film gas barrier layer having a thickness of 20 to 50 μm , a heat insulating layer, a thin film gas barrier layer, and a dye receiving layer are sequentially provided on a base sheet, A resin comprising a thin film gas barrier film made of an ethylene vinyl alcohol copolymer (EVOH) film having a thickness of 1 to 10 μm as a thin film gas barrier layer and containing a foaming agent or a thermally expandable microcapsule on one side of the film After the resin layer side of the thin film gas barrier film and the base sheet are extruded and laminated with a resin that becomes a thick film gas barrier layer, the film is heated and pressurized with a hot roll, and the foaming agent is provided. The resin layer contained is expanded or expanded to form a heat insulating layer, and then the dye is received on the side opposite to the surface on which the heat insulating layer of the thin film gas barrier film is provided. The layer is formed. As a result, the heat insulating layer has high cushioning properties and heat insulating properties, and the heat insulating layer is sandwiched between gas barrier layers, preventing the gas inside the heat insulating layer from leaking to the outside, and the heat insulating layer. It is possible to keep the function of the layer so that the function does not deteriorate with time.

  FIG. 1 is a schematic sectional view showing one best embodiment which is a thermal transfer image receiving sheet of the present invention. This is a thermal transfer image receiving sheet 1 in which a thick film gas barrier layer 3, a heat insulating layer 4, a thin film gas barrier layer 5, and a dye receiving layer 6 are sequentially laminated on a base sheet 2. A thin film gas barrier film is used as the thin film gas barrier layer 5, a resin layer containing a foaming agent or a thermally expandable microcapsule is provided on one side of the film, the resin layer side of the thin film gas barrier film, After the base sheet 2 is extruded and laminated with the resin that becomes the thick film gas barrier layer 3, it is heated and pressurized with a hot roll to foam or expand the resin layer containing the foaming agent, thereby forming the heat insulating layer 4. Then, the dye receiving layer 6 is formed on the side opposite to the surface on which the heat insulating layer 4 of the thin film gas barrier film is provided. In this case, the thin film gas barrier film and the adhesive for extruding and laminating the base sheet become the above thick film gas barrier layer.

  FIG. 2 is a schematic sectional view showing another best embodiment which is a thermal transfer image receiving sheet of the present invention. It is a thermal transfer image receiving sheet 1 in which an adhesive layer 7, a thick film gas barrier layer 3, a heat insulating layer 4, a thin film gas barrier layer 5, and a dye receiving layer 6 are laminated in this order on a base sheet 2. A thin film gas barrier film is used as the thin film gas barrier layer 5, a resin layer containing a foaming agent or a thermally expandable microcapsule is provided on one side of the film, the resin layer side of the thin film gas barrier film, When laminating the thick film gas barrier film as the thick film gas barrier layer 3 while heating and pressurizing with a hot roll, the resin layer is foamed or expanded to form the heat insulating layer 4, and then the thin film A dye-receiving layer 6 is formed on the side opposite to the surface on which the heat insulating layer 4 of the gas barrier film is provided, and then the side opposite to the surface on which the heat insulating layer 4 of the thick film gas barrier film is provided; The material sheet 2 is laminated with an adhesive layer 7 and bonded together. The thermal transfer image-receiving sheet of the present invention is not limited to the form shown in FIGS. 1 and 2, and a back layer is provided on the other surface of the base sheet, or between any of the illustrated layers. It is possible to provide an intermediate layer or add layers as necessary.

(Substrate sheet)
The base sheet 2 has a role of holding a heat insulating layer, a receiving layer, and the like, and heat is applied at the time of thermal transfer. Therefore, the base sheet 2 preferably has mechanical strength that does not hinder handling even in a heated state. The material of such a base sheet is, for example, condenser paper, glassine paper, sulfuric acid paper, or high-size paper, synthetic paper (polyolefin type, polystyrene type), fine paper, art paper, coated paper, cast coated paper , Wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, paperboard, cellulose fiber paper, or polyester, polyacrylate, polycarbonate, polyurethane, polyimide, polyetherimide, cellulose derivatives , Polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, acrylic, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone, polyether resin Film of phon, tetrafluoroethylene / perfluoroalkyl vinyl ether, polyvinyl fluoride, tetrafluoroethylene / ethylene, tetrafluoroethylene / hexafluoropropylene, polychlorotrifluoroethylene, polyvinylidene fluoride, etc. A white opaque film formed by adding a white pigment or filler to a synthetic resin or a foamed foam sheet can also be used.

  In the present invention, it is particularly preferable to use pulp paper such as high-quality paper, art paper, coated paper, and cast coated paper among the above-mentioned base material sheets because the cost can be reduced. In addition, the laminated body by the arbitrary combinations of the said base material sheet can also be used. The thickness of the base sheet used in the present invention may be arbitrary, and is usually about 10 to 300 μm. Moreover, when the adhesiveness of the said base material sheet and the layer provided on it is scarce, it is preferable to perform various primer processing and corona discharge processing on the surface of a base material sheet.

(Thick film gas barrier layer)
The thick film gas barrier layer 3 in the present invention takes either a stretched or non-stretched film form as a thick film gas barrier film, or an adhesive layer form by a laminating adhesive in extrusion lamination. Can do. In the form of the film, a film (including partial vapor deposition) obtained by depositing metallic aluminum on a biaxially stretched polyethylene terephthalate film, a biaxially stretched polypropylene film, or the like can be used. In addition, a film in which silicon oxide or a metal oxide is vapor-deposited, polyvinylidene chloride, a film in which polyvinyl alcohol is coated, a film such as an ethylene vinyl alcohol copolymer (EVOH), or the like can be given.

In the case of the above adhesive layer, for example, polyethylene, ethylene-α-olefin copolymer, polypropylene, polybutene, polyisobutene, poisoisobutylene, polybutadiene, polyisoprene, ethylene-methacrylic acid copolymer, or ethylene-acrylic acid. Copolymers of ethylene and unsaturated carboxylic acids such as copolymers, or acid-modified polyolefin resins modified with them, ethylene-ethyl acrylate copolymers, ionomer resins, ethylene-vinyl acetate copolymers, etc. Etc. can be used. As described above, a thick film gas barrier layer can be formed by any method of a film and an adhesive layer, but the thickness of the thick film gas barrier layer can be changed as appropriate. It is about m ² (solid content).

(Insulation layer)
The heat insulating layer 4 used in the present invention is formed by the following process. A thin film gas barrier film is used as the thin film gas barrier layer, a resin layer containing a foaming agent or a thermally expandable microcapsule is provided on one side of the film, the resin layer side of the thin film gas barrier film, When the material sheet is laminated while being heated and pressed with a heat roll, the resin layer comes into contact with the heat roll, whereby the resin layer is foamed or expanded, and the heat insulating layer 4 is formed. Moreover, after extruding and laminating the resin layer side of the above-mentioned thin film gas barrier film and the resin that becomes the thick film gas barrier layer, the base sheet is heated and pressurized with a hot roll to contain a foaming agent. Foams or expands to form a heat insulating layer. The heat insulating layer is mainly composed of a foaming agent or a thermally expandable microcapsule and a binder resin.

  As the foaming substance, a chemical foaming agent, a thermally expandable microcapsule, or the like can be used. Examples of chemical blowing agents include azo compounds such as azodicarbonamide and azobisisobutyronitrile, nitroso compounds such as dinitrosopentamethylenetetramine, p-toluenesulfonyl hydrazide, p, p′-oxybis (benzenesulfonyl hydrazide) and the like. Organic foaming agents such as β-keto acids such as sulfonylhydridide compounds, oxaloacetic acid, malonic acid, tartonic acid, and acetonedicarboxylic acid, and inorganic foaming agents such as sodium bicarbonate, ammonium bicarbonate, and ammonium carbonate. . A foaming aid is added to these to adjust the foaming temperature and foaming amount.

  Examples of thermally expandable microcapsules include low-boiling hydrocarbons such as n-butane, i-butane, pentane, and neopentane. Acrylic acids such as vinylidene chloride, acrylonitrile, and methyl methacrylate are used as capsule wall films There are those using thermoplastic resins mainly composed of aromatic vinyl compounds such as esters and styrene, and commercially available products include Matsumoto Microsphere F-30, F-50, F-80 (Matsumoto Yushi Co., Ltd.) Product name), Expandel WU-461, WU-551, WU-091, WU-051 (manufactured by Nippon Philite Co., Ltd.) and the like. In the case of thermally expandable microcapsules, those having a volume average particle size of about 1 to 15 μm before foaming and those having a particle size of 5 to 50 μm after foaming are preferable. When the volume average particle diameter before foaming is 15 μm or more and the particle diameter after foaming is 50 μm or more, the surface of the heat insulating layer is made uneven, which adversely affects the image quality of the formed image.

  The foaming agent or the thermally expandable microcapsule preferably has a partition wall softening temperature or foaming start temperature of 100 ° C. or less and an optimum foaming temperature (the temperature at which the foaming ratio becomes the highest in a heating time of 1 minute) of 140 ° C. or less. . By using a foaming material having a low foaming temperature, thermal wrinkles and curling of the base material during foaming can be prevented. This thermally expandable microcapsule having a low foaming temperature can be obtained by adjusting the blending amount of a thermoplastic resin such as polyvinylidene chloride or polyacrylonitrile forming the partition walls. The volume average particle diameter is 1 to 15 μm. In the heat insulating layer using this microcapsule, the bubbles obtained by foaming are closed cells, foamed by a simple process of heating alone, the thickness of the foamed layer can be easily controlled by the amount of microcapsules, etc. There are advantages.

Binder resins include water-based adhesives such as water-soluble adhesives and latex adhesives, solvent-based adhesives, and adhesives such as monomers, oligomers or prepolymers having ethylenically unsaturated bonds that are cured by electron beams or ultraviolet rays. The agent can be used.
Examples of water-soluble adhesives include proteins such as gelatin, albumin and casein, starches, celluloses, water-soluble natural polymer compounds such as agar, sodium alginate and arabic gum, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid and polyacrylamide. And water-soluble synthetic polymer compounds such as maleic acid copolymers.

  Examples of latex adhesives include styrene / butadiene latex, acrylonitrile / butadiene latex, acrylic ester latex, vinyl acetate latex, vinylidene chloride latex, methyl methacrylate / butadiene latex, and their carboxy-modified latex. .

  Solvent-based adhesives include natural resins such as rosin, ceramics, copal, dalman, gilsonite, zein and hardened rosin, ester gum and other rosin esters, maleic resin, fumaric acid resin, duplex rosin, polymerized rosin, rosin Modified phenol resin, cellulose derivative resin such as methyl cellulose, ethyl cellulose, phenol resin, xylene resin, urea resin, melamine resin, ketone resin, chroman indene resin, petroleum resin, terpene resin, cyclized rubber, chlorinated rubber, alkyd resin, polyamide Resin, acrylic resin, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, polyvinyl acetate, ethylene / maleic anhydride copolymer, styrene / maleic anhydride copolymer, methyl vinyl ether / maleic anhydride copolymer, Isobutylene Water maleic acid copolymer, polyvinyl alcohol, modified polyvinyl alcohol, butyral resin, acetal resin, polyvinyl pyrrolidone, chlorinated polypropylene styrene resins, epoxy resins, synthetic resins such as polyurethane resin.

  Monomers, oligomers or prepolymers having ethylenically unsaturated bonds that are cured by electron beam or ultraviolet rays include styrene, methyl methacrylate, butyl methacrylate, polyethylene glycol diacrylate, propylene glycol dimethacrylate, pentaerythritol acrylate, trimethylolpropane. Examples include diacrylate, pentaerythritol triacrylate, hexanediol diacrylate, a reaction product of epoxy resin and acrylic acid, a reaction product of methacrylic acid, pentaerythritol, and acrylic acid, and a condensate of maleic acid, diethylene glycol, and acrylic acid.

  The binder resin can be selected from general-purpose synthetic resins as described above in consideration of wettability and adhesiveness with the adhesive. The amount of the foaming agent, which is a foaming substance, or the thermally expandable microcapsule is preferably in the range of 0.5 to 100 parts by mass with respect to 100 parts by mass of the binder resin. If it is less than 0.5 mass part, the cushioning property of a heat insulation layer is low, and the effect of heat insulation layer formation is not acquired. When it exceeds 100 parts by mass, the hollow ratio after foaming becomes too large, the mechanical strength of the heat insulating layer is lowered, and it becomes impossible to withstand normal handling. In addition, the surface of the heat insulating layer loses its smoothness and adversely affects the appearance and the print quality.

  The heat-insulating layer is, for example, a foamed substance and a binder resin as mentioned above, and, if necessary, an additive, and dissolved in an appropriate organic solvent or dispersed in an organic solvent or water. It is formed by applying and drying by a forming means such as a gravure printing method, a screen printing method, or a reverse roll coating method using a gravure plate. Moreover, the thickness of the whole heat insulation layer is 10-100 micrometers after foaming. When it is 10 μm or less, cushioning properties and heat insulation are insufficient, and when it is 100 μm or more, the effect of the heat insulating layer is not improved and the strength is lowered. In the case of laminating the above thick film gas barrier layer as a thick film gas barrier film, and when forming a thick film gas barrier layer by extruding and laminating a resin, the heat insulating layer is a thin film gas barrier property. Since the resin layer is foamed or expanded, the function of the foamed layer can be fully exerted even when the thickness of the foamed layer formed by foaming or expanding the resin layer is relatively small. .

(Thin gas barrier layer)
The thin film gas barrier layer 5 in the thermal transfer image-receiving sheet of the present invention has a resin layer containing a foaming agent or a heat-expandable microcapsule on one side, and a dye-receiving layer on the other side. In addition to having the role of holding the layer, heat is applied at the time of thermal transfer, so it has mechanical strength that does not hinder handling even in a heated state, and with the thick gas barrier layer described above, The resin layer containing the foaming agent or thermally expandable microcapsule has a so-called gas barrier property that prevents the gas inside the heat insulating layer formed by foaming or expansion from leaking outside, and the performance of the heat insulating layer It has a role to prevent the decrease.

  As a material constituting such a thin film gas barrier layer, for example, a metal aluminum vapor deposition film (including partial vapor deposition) can be used for a biaxially stretched polyethylene terephthalate film, a biaxially stretched polypropylene film, or the like. In addition, a film in which silicon oxide or a metal oxide is vapor-deposited, polyvinylidene chloride, a film in which polyvinyl alcohol is coated, a film such as an ethylene vinyl alcohol copolymer (EVOH), or the like can be given. The thin film as the thin film gas barrier layer used in the present invention has a thickness of about 1 to 10 μm. The thickness of the thin gas barrier layer is smaller than that of the thick gas barrier layer described above, because the effect of the heat insulating layer is sufficiently exhibited during thermal transfer recording, mainly for dye acceptance. It is for improving the dyeing property in a layer. Moreover, when the adhesiveness of the said thin film and the layer provided on it is scarce, it is preferable to perform various primer processing and corona discharge processing on the surface of a thin film.

(Dye-receiving layer)
The dye receiving layer 6 provided on the thin film as the thin film gas barrier layer is for receiving the dye transferred from the thermal transfer sheet when heated and maintaining the formed image. The dye-receiving layer in the present invention is preferably formed of an organic solvent-soluble resin obtained by dissolving the following resin in an organic solvent.

  Examples of the resin for forming the receiving layer include polyolefin resins such as polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, polyvinyl acetate, ethylene vinyl acetate copolymer, and vinyl chloride vinyl acetate copolymer. Polymers, vinyl resins such as polyacrylic esters, acetal resins such as polyvinyl formal, polyvinyl butyral, polyvinyl acetal, various saturated and unsaturated polyester resins, polycarbonate resins, cellulose resins such as cellulose acetate, polystyrene, acrylic styrene Examples thereof include styrene resins such as copolymers, acrylonitrile-styrene copolymers, polyamide resins such as urea resins, melamine resins, and benzoguanamine resins. These resins can be arbitrarily blended and used within a compatible range.

  In addition, the receiving layer resin as described above may cause fusion with the binder resin of the dye layer that retains the dye during thermal transfer of image formation. Therefore, in order to obtain good releasability, phosphate ester, surfactant It is preferable to internally add various releasing agents such as an agent, a fluorine compound, a fluorine resin, a silicone compound, a silicone oil, and a silicone resin into the receiving layer, and in particular, a modified silicone oil is preferably added and cured. .

  One or more release agents are used. Moreover, the addition amount of the release agent is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the dye receiving layer forming resin. When the range of the addition amount is not satisfied, problems such as fusion between the sublimation type thermal transfer sheet and the dye-receiving layer of the thermal transfer image receiving sheet or a decrease in printing sensitivity may occur. By adding such a release agent to the dye receiving layer, the release agent bleeds out on the surface of the dye receiving layer after the transfer to form a release layer. These releasing agents may be separately applied on the dye receiving layer without being added to the dye receiving layer forming resin.

The dye-receiving layer is prepared by dissolving a resin obtained by adding a necessary additive such as a release agent to the surface of a thin film in an appropriate organic solvent, or by dispersing a dispersion in an organic solvent or water. It is formed by applying and drying by a forming means such as a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate. In forming the dye-receiving layer, a white pigment, a fluorescent whitening agent, or the like can be added for the purpose of improving the whiteness of the dye-receiving layer and further enhancing the sharpness of the transferred image. The dye-receiving layer formed as described above may have any thickness, but generally has a thickness of 1 to 50 g / m ^{2 in} a dry state. The receiving layer can also be provided by extrusion coating using a material obtained by kneading each constituent material with heat.

(Method for producing thermal transfer image-receiving sheet)
The manufacturing method of the thermal transfer image receiving sheet of the present invention includes the following two methods. One uses a thin film gas barrier film as the thin film gas barrier layer, and a resin layer containing a foaming agent or a thermally expandable microcapsule is provided on one side of the film, and the resin layer side of the thin film gas barrier film When the thick film gas barrier film as the thick film gas barrier layer is laminated while being heated and pressurized with a hot roll, the resin layer is foamed or expanded to form a heat insulating layer, and then the thin film A dye-receiving layer is formed on the side opposite to the surface on which the heat insulating layer of the gas barrier film is provided, and then the side opposite to the surface on which the heat insulating layer of the thick film gas barrier film is provided; They are formed by laminating together.

  Secondly, a thin film gas barrier film is used as the thin film gas barrier layer, a resin layer containing a foaming agent or a thermally expandable microcapsule is provided on one side of the film, and the resin layer side of the above thin film gas barrier film And after extruding and laminating the resin that becomes the thick film gas barrier layer to the base sheet, it is heated and pressurized with a hot roll to foam or expand the resin layer containing the foaming agent to form a heat insulating layer. Then, a dye receiving layer is formed on the side opposite to the surface on which the heat insulating layer of the thin film gas barrier film is provided.

  In the former production method, when laminating the resin layer side of the thin film gas barrier film and the thick film gas barrier film while heating and pressurizing with a hot roll, the resin layer foams or expands by heating with the hot roll. Thus, a heat insulating layer is formed. In this case, as a laminating method, an adhesive is applied to the resin layer side of the thin film gas barrier film or the thick film gas barrier film side, and before the adhesive is dried, the resin of the thin film gas barrier film is used. After contacting the layer side and the base sheet, and then heating and pressing to dry and bond the adhesive, the so-called wet laminating method, and after applying the adhesive and immediately drying the adhesive The thin film gas barrier film can be laminated using a so-called dry laminating method in which the resin layer side of the thin film gas barrier film and the base sheet are brought into contact with each other and pressed and bonded. The heat roll at the time of laminating heats the resin layer containing the foaming agent or the heat-expandable microcapsule to a temperature higher than the temperature at which it can be foamed or expanded, especially the thin film gas barrier film. It is necessary to heat the surface of the roll that comes into contact with the roller.

  In the latter production method, the resin layer side of the thin film gas barrier film and the base sheet are extruded and laminated with a resin that becomes a thick film gas barrier layer, and then heated and pressurized with a hot roll to contain a foaming agent. The heat insulation layer is formed by foaming or expanding the resin layer. In this case, the hot roll is provided at a position after the extrusion laminating process, and the roll surface temperature, particularly the surface temperature of the roll in contact with the thin film gas barrier film, is supplied from the head at the time of extrusion. It is necessary to heat at a temperature lower than the melting point of the molten resin.

  In either case of the former or the latter production method, a resin layer containing a foaming agent is foamed or expanded to form a dye receiving layer after the heat insulating layer is formed. Since the surface of the thin film gas barrier film is somewhat uneven, the dye receiving layer is formed by a means such as a reverse roll coating method using a gravure plate with good leveling, or by the printing pressure of the dye receiving layer. Care must be taken so that the foaming state of the layer does not change and the cushioning properties and the like do not deteriorate.

The present invention will be described more specifically with reference to the following examples. In the text, “%” or “%” is based on mass unless otherwise specified. As a thin film gas barrier layer, an ethylene vinyl alcohol copolymer (EVOH) film having a thickness of 5 μm is used, and a resin layer 1 having the following composition is applied to one side of the film in a dry state by gravure coating to apply 5 g / m ² . A biaxially stretched polyester film formed in a quantity and deposited on the resin layer side of the EVOH film and an aluminum vapor deposition (deposition thickness of 550 mm) as a thick gas barrier layer with a total thickness of 20 μm is heated in a hot roll (thin film gas barrier film). When laminating while heating and pressing at a surface temperature of the roll in contact with the resin, the resin layer was foamed or expanded to form a heat insulating layer.

(Resin layer 1)
30 parts of ethylene-vinyl acetate copolymer resin (Emercel, manufactured by Eiwa Chemical Co., Ltd.)
1 part of foaming agent (Emercel BA-1, manufactured by Eiwa Chemical Industry Co., Ltd.)
Water / IPA = 1/1 (mass ratio) 70 parts

Thereafter the surface opposite that provided with the heat insulating layer of the thin film gas barrier film, in the following composition, an intermediate layer, a dye receiving layer sequentially, dried, each ^{1g / m 2, 4g / m} 2 Next, the substrate sheet of coated paper having a basis weight of 158 g / m ² is bonded with the following composition. The layer was coated to a thickness of ² g / m ² after drying, and bonded by a dry laminating method to produce the thermal transfer image receiving sheet of Example 1.

(Middle layer)
Polyester resin (Byron 200, manufactured by Toyobo Co., Ltd.) 10 parts Titanium oxide (TCA-888, manufactured by Tochem Products) 20 parts Methyl ethyl ketone / toluene = 1/1 (mass ratio) 120 parts

(Dye-receiving layer)
100 parts of vinyl chloride-vinyl acetate copolymer (Electrochemical Industry Co., Ltd., # 1000A)
Amino-modified silicone 5 parts (Shin-Etsu Chemical Co., Ltd., X22-3050C)
Epoxy-modified silicone 5 parts (Shin-Etsu Chemical Co., Ltd., X22-3000E)
Methyl ethyl ketone / toluene = 1/1 (mass ratio) 400 parts

(Adhesive layer)
Polyurethane resin (A-969V, manufactured by Mitsui Takeda Chemical Co., Ltd.) 30 parts Isocyanate (A-5, manufactured by Mitsui Takeda Chemical Co., Ltd.) 10 parts Ethyl acetate 100 parts

  A thick gas barrier layer of the thermal transfer image-receiving sheet prepared in Example 1 was changed to an EVOH barrier film having a total thickness of 20 μm on which a thin film of silicon oxide (thickness: 550 mm) was deposited. Thus, a thermal transfer image receiving sheet of Example 2 was obtained.

(Reference Example 3)
Example except that the thin film gas barrier layer of the thermal transfer image-receiving sheet prepared in Example 1 was changed to a polyethylene terephthalate (PET) film having a thickness of 5 μm, and the thick gas barrier layer was changed to a polyethylene terephthalate (PET) film having a thickness of 50 μm. In the same manner as in Example 1, a thermal transfer image receiving sheet of Reference Example 3 was obtained.

As a thin film gas barrier layer, an ethylene vinyl alcohol copolymer (EVOH) film having a thickness of 5 μm is used, and a resin layer 2 having the following composition is applied to one side of the film in a dry state by gravure coating to apply 5 g / m ² . The resin layer side of the EVOH film, the base sheet of the coated paper having a basis weight of 158 g / m ² , the resin having the following composition that becomes the thick film gas barrier layer, and the EC laminate did. The thickness of the laminate adhesive layer, that is, the thick film gas barrier layer is 20 g / m ² (solid content).

(Resin layer 2)
Thermal expansion microcapsule-containing resin 50 parts (New die foam, manufactured by Dainichi Seika Kogyo Co., Ltd.)
Ethyl acetate / IPA = 1/2 (mass ratio) 50 parts

(EC laminate resin)
Polyethylene resin (Sumikasen 10P, Mitsui Sumitomo Chemical Co., Ltd.)

After the EC lamination, the resin layer containing the foaming agent is foamed or expanded by heating and pressurizing with a hot roll (the surface temperature of the roll in contact with the thin film gas barrier film is 130 ° C.). After that, the intermediate layer and the dye receiving layer similar to those of Example 1 are sequentially dried on the side opposite to the surface on which the heat insulating layer of the thin film gas barrier film is provided, and then 1 g / m ² , 4 g, respectively. The thermal transfer image receiving sheet of Example 4 was produced by forming the film to a thickness of / m ² .

(Reference Example 5)
A thermal transfer image-receiving sheet of Reference Example 5 was obtained in the same manner as in Example 4 except that the thin film gas barrier layer of the thermal transfer image-receiving sheet prepared in Example 4 was changed to a polyethylene terephthalate (PET) film having a thickness of 5 μm. .

(Comparative Example 1)
A polyethylene terephthalate (PET) film having a thickness of 5 μm is used as the thin film gas barrier layer, and the resin layer 1 having the composition used in Example 1 is dried on the one side of the film by gravure coating, and 5 g / m ² . formed by coating amount, and the resin layer side of the PET film, the base sheet of coated paper having a basis weight of 158 g / m ^2, the adhesive layer thickness after drying 2 g / m ² of composition used in example 1 It was coated so as to be, and bonded together by a dry laminating method. After the dry lamination, the resin layer was foamed or expanded by heating and pressing with a hot roll (the surface temperature of the roll contacting the thin film gas barrier film was 130 ° C.) to form a heat insulating layer. Thereafter, an intermediate layer and a dye receiving layer similar to those of Example 1 were sequentially dried on the side opposite to the surface on which the heat insulating layer of the thin film gas barrier film was provided, and then 1 g / m ² and 4 g / m, respectively. A thermal transfer image-receiving sheet of Comparative Example 1 was produced by forming the film to a thickness of ² .

(Evaluation)
Next, the thermal transfer image receiving sheets of Examples and Comparative Examples were evaluated as follows.
<Evaluation method>
(Thermal transfer recording)
As the thermal transfer film, a transfer film UPC-740 for sublimation transfer printer UP-D70A manufactured by Sony Corporation is used, and the thermal transfer image-receiving sheets of the above-mentioned examples and comparative examples are used, with the dye layer and the dye-receiving layer surface facing each other. Thermal transfer recording was performed using the thermal head from the back surface of the thermal transfer film in the order of superposition, Y, M, C, and protective layer under the following conditions.

(Print conditions)
A gradation image was formed by thermal transfer recording under the following conditions.
-Thermal head: KYT-86-12MFW11 (manufactured by Kyocera Corporation)
-Heating element average resistance: 4412 (Ω)
・ Print density in the main scanning direction: 300 dpi
-Sub-scanning direction printing density: 300 dpi
Applied power: 0.136 (w / dot)
1 line cycle: 6 (msec.)
-Printing start temperature: 30 (° C)
-Print size: 100mm x 150mm
・ Gradation printing: Using a multi-pulse test printer that can vary the number of divided pulses from 0 to 255 with a pulse length that equally divides one line period into 256 within one line period, the duty of each divided pulse The ratio is fixed at 40%, and the number of pulses per line cycle is increased in increments of 17 from 0 in 1 step, 17 in 3 steps, 34 in 3 steps, and from 0 to 255, depending on the gradation. Thus, 16 gradations from 1 step to 16 steps were controlled.
・ Transfer the protective layer: Using a multi-pulse test printer that can vary the number of divided pulses from 0 to 255 within a line period and dividing the line period into 256 equally divided pulses, The duty ratio was fixed at 50%, the number of pulses per line period was fixed at 210, solid printing was performed, and the protective layer was transferred to the entire printed surface.

(Print density)
The maximum reflection density of the printed matter was measured with a visual filter using an optical reflection densitometer (Macbeth RD-918, manufactured by Macbeth).
Evaluation: .largecircle .. Maximum reflection density of 1.7 or more.
X: The maximum reflection density is less than 1.7.

(Printed product appearance)
The printed matter was visually observed and judged according to the following criteria.
Evaluation: ○ ··· No density unevenness.
× ··· There is uneven density.

The evaluation results are as shown in Table 1 below.

The obtained evaluation results were all printed immediately after the thermal transfer image-receiving sheet was prepared. After the thermal transfer image-receiving sheets of the examples and comparative examples were prepared, they were left in a 40 ° C. environment for one week (long term When the same evaluation as described above was performed, the thermal transfer image-receiving sheets of Examples 1, 2, and 4 did not cause density unevenness in the appearance of the printed matter, but the thermal transfer of Reference Examples 3 and 5 The image receiving sheet was slightly uneven in density. Further, the thermal transfer image-receiving sheet of Comparative Example 1 had remarkably uneven density, and the print density was remarkably lowered.

It is a schematic sectional drawing which shows one best embodiment which is the thermal transfer image receiving sheet of this invention. It is a schematic sectional drawing which shows other best embodiment which is the thermal transfer image receiving sheet of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal transfer image-receiving sheet 2 Base material sheet 3 Thick film gas barrier layer 4 Heat insulation layer 5 Thin film gas barrier layer 6 Dye receiving layer 7 Adhesive layer

Claims (3)

A thin film gas barrier layer having a thickness of 20 to 50 μm , a heat insulating layer, a thin film gas barrier layer composed of an ethylene vinyl alcohol copolymer (EVOH) film having a thickness of 1 to 10 μm , and a dye receiving layer are sequentially formed on the base sheet. A thermal transfer image receiving sheet characterized by being laminated. In the method for producing a thermal transfer image receiving sheet, in which a thick film gas barrier layer, a heat insulating layer, a thin film gas barrier layer, and a dye receiving layer having a thickness of 20 to 50 μm are sequentially provided on a substrate sheet, the thin film gas barrier layer Using a thin film gas barrier film made of an ethylene vinyl alcohol copolymer (EVOH) film having a thickness of 1 to 10 μm , and providing a resin layer containing a foaming agent or a thermally expandable microcapsule on one side of the film, When laminating the resin layer side of the thin film gas barrier film and the thick film gas barrier film as the thick film gas barrier layer with a hot roll while heating and pressurizing, the resin layer is foamed or expanded, A heat insulating layer is formed, and then a dye receiving layer is formed on the side opposite to the surface on which the heat insulating layer of the thin film gas barrier film is provided. A method for producing a thermal transfer image-receiving sheet, comprising: forming a laminate of a base sheet and a side opposite to the surface on which the heat insulating layer of the thick film gas barrier film is provided. In the method for producing a thermal transfer image receiving sheet, in which a thick film gas barrier layer, a heat insulating layer, a thin film gas barrier layer, and a dye receiving layer having a thickness of 20 to 50 μm are sequentially provided on a substrate sheet, the thin film gas barrier layer Using a thin film gas barrier film made of an ethylene vinyl alcohol copolymer (EVOH) film having a thickness of 1 to 10 μm , and providing a resin layer containing a foaming agent or a thermally expandable microcapsule on one side of the film, After extruding and laminating the resin layer side of the thin film gas barrier film and the base sheet with a resin that becomes a thick film gas barrier layer, the resin layer containing the foaming agent is heated and pressurized with a hot roll. Foam or expand to form a heat insulating layer, and then form a dye receiving layer on the opposite side of the thin film gas barrier film on which the heat insulating layer is provided. A method for producing a thermal transfer image-receiving sheet.

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