JP2013001088A - Transparent sheet for printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent sheet for printing whose transparent heat-resistant sheet has an ink receiving layer and which is excellent in color printability by, for instance, a sublimation type direct thermal transfer method or a sublimation type indirect thermal transfer method, and is suitable for a plastic card having such properties as thermal fusion, transparency, sheet transportability, mold releasability from a mold after hot pressing, heat resistance, foldability, and abrasion resistance.SOLUTION: The transparent sheet for printing is produced by forming the ink receiving layer comprised of a polyester resin having a vinyl chloride copolymer or a functional group on at least one side of a transparent base material sheet comprised of a noncrystalline aromatic polyester resin whose glass transition temperature is 90°C or higher.

Description

  The present invention particularly relates to a transparent sheet for printing excellent in color printing suitability by a sublimation type thermal transfer method, and can be suitably used for a plastic card.

  Today, plastic IC cards are ID cards (employee cards, student cards, admission cards, security cards, etc.), personal cards, bank cards, credit cards, transportation cards, health insurance cards, and various membership cards that record personal information. A wide variety of cards are used in particular with the development of a globalized society. Personal card holdings are also increasing. Such a card is manufactured by punching a plurality of plastic sheets after heat lamination, and vinyl chloride resin (PVC) is mainly used for the plastic sheets. In addition to being inexpensive, PVC does not have any problems with strength properties required for plastic cards, such as ease of heat lamination and repeated bending fatigue properties. In addition, it is excellent in sublimation type thermal transfer printability generally used in plastic cards, and images and characters can be printed in color using white sublimation type thermal transfer printers from plain white blank cards. Although there are problems with waste and incineration, it is still used in many countries around the world. On the other hand, there are also movements in various countries in which non-crystalline aromatic polyester resins are used instead of PVC due to environmental problems as described above. However, the non-crystalline aromatic polyester resin is inferior in sublimation thermal transfer printability. Therefore, it is difficult to color-print images and characters from a white plain blank card using a card sublimation thermal transfer printer.

  Patent Document 1 discloses a non-stretched polyester resin composition comprising two kinds of polyesters having different molar ratios of ethylene glycol units and 1,4-cyclohexanedimethanol units, and an aromatic polycarbonate. A sheet for an identification card on which one side is matted is described.

JP-A-11-100451

  In the identification card sheet of Patent Document 1, application of printing aptitude such as printing ink adhesiveness, ink landing finish, and printing machine aptitude is simply by embossing formed on the surface of the polyester resin sheet. The embossing can provide a certain degree of printability, but is inferior in color reproducibility and sharpness by color printing using a sublimation type direct thermal transfer method or a sublimation type indirect heat transfer method. In addition, printed characters, designs, and the like are simply on the embossed uneven surface, and there is a problem that they are easily peeled off.

  The present invention has been made to solve the above-described problems, and is a plastic card having excellent printability, heat resistance, good adhesion between a transparent base sheet and an ink receiving layer, and high transparency. A suitable printing transparent sheet can be provided.

[1] The present invention is a transparent sheet for printing in which an ink receiving layer is provided on at least one side of a transparent substrate sheet, and the transparent substrate sheet is an amorphous aromatic polyester based glass transition temperature of 90 ° C. or higher. It is made of a resin and is configured as a sheet having a thickness of 50 to 200 μm and a total light transmittance of 70% or more, and the ink receiving layer is made of a vinyl chloride copolymer or a polyester resin having a functional group, A transparent sheet for printing, which is formed as a layer having a dry film thickness of 1 to 20 μm on one side of the transparent substrate sheet in a solution containing a transparent medium.

[2] From the amorphous aromatic polyester resin composition, wherein the transparent base sheet comprises 100 parts by mass of a non-crystalline aromatic polyester resin having a glass transition temperature of 90 ° C. or more and 0.01 to 3 parts by mass of a lubricant. And further containing 0.1 to 5 parts by mass of an antioxidant and / or anti-coloring agent and 0.1 to 5 parts by mass of an ultraviolet absorber and / or a light stabilizer. Transparent sheet for printing.

[3] The [1] or [2], wherein the vinyl chloride copolymer has a copolymerization ratio of vinyl chloride and another monomer of at least 30% by mass of vinyl chloride and an average degree of polymerization of 100 to 2000. The transparent sheet for printing as described in 2.

[4] A copolymer component other than vinyl chloride of the vinyl chloride copolymer is vinyl ester, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, olefin, acrylonitrile, styrene, vinylidene chloride, vinyl ether, and aromatic The transparent sheet for printing according to any one of [1] to [3], which is one or more selected from vinyl compounds.

[5] The transparent sheet for printing according to [1] or [2], wherein the polyester resin having the functional group is a polyester resin having a sulfonate group or a carboxylate group.

[6] The printing transparent sheet according to any one of [1] to [5], which is for a plastic card.

  According to the present invention, it is possible to provide a printing transparent sheet suitable for a plastic card, which has excellent heat resistance, printability, good adhesion between a transparent base sheet and an ink receiving layer, and high transparency. Can have a very remarkable effect. In particular, the color printing suitability by the sublimation type direct thermal transfer method or the sublimation type indirect heat transfer method is extremely excellent, and the printing suitability is excellent such that there is no color distortion and color blur and printing having a good density can be performed. Further, the ink receiving layer is firmly adhered to the transparent substrate sheet, and does not peel off or change in quality. Furthermore, it has sheet transportability, release properties from the mold after hot pressing, and has heat resistance, bending resistance, and wear resistance.

  Hereinafter, although the form for implementing the transparent sheet for printing which provided the ink receiving layer in at least one side of the transparent base material sheet of this invention is demonstrated concretely, it is not limited to the following embodiment.

[1] Configuration of transparent sheet for printing provided with ink receiving layer:
The transparent sheet for printing has a configuration in which an ink receiving layer is provided on at least one side of a transparent substrate sheet. The transparent substrate sheet is made of a non-crystalline aromatic polyester resin having a glass transition temperature of 90 ° C. or higher. The transparent substrate sheet has a thickness of 50 to 200 μm and a total light transmittance of 70% or more. The ink receiving layer is made of a vinyl chloride copolymer or a polyester-based resin having a functional group, and has a dry film thickness of 1 to 20 μm on one side of the transparent substrate sheet in a solvent or water-based solution. It is comprised as a layer which has.

  The transparent sheet for printing provided with the ink receiving layer of the present invention has a dry film thickness of 1 to 20 μm on a sheet of 50 to 200 μm thick made of a non-crystalline aromatic polyester resin that is a transparent base sheet. A transparent sheet for printing, which is provided with an ink receiving layer formed by coating and drying. Although the drying conditions after the application of the ink receiving layer will be described later in detail, the drying temperature is generally 60 to 120 ° C. and the drying time is about 30 seconds to 10 minutes using a conveyor type drying furnace. If the heat resistance of the transparent substrate sheet is poor, “streaks” or “wrinkles” may occur along the sheet traveling direction due to the softening of the transparent substrate sheet in the drying process after the ink receiving layer is applied. Cause practical problems. For this reason, the non-crystalline aromatic polyester resin constituting the transparent base sheet of the present invention is required to be a non-crystalline aromatic polyester resin having a glass transition temperature of 90 ° C. or higher. Here, in the transparent base sheet made of the non-crystalline aromatic polyester-based resin having a glass transition temperature of less than 90 ° C., as described above, in the drying process after coating the ink receiving layer on one side of the transparent base sheet, Since the sheet is softened, “streaks” are generated along the sheet traveling direction and “wrinkles” are generated.

[2] Transparent substrate sheet:
The transparent substrate sheet of the present invention is a transparent resin mainly composed of an amorphous aromatic polyester resin, and further a transparent resin mainly composed of an amorphous polyester resin having a glass transition temperature of 90 ° C. or higher. Consists of. This transparent substrate sheet is a transparent sheet excellent in heat resistance formed from, for example, a sheet formed by melt extrusion molding.

  The amorphous aromatic polyester resin constituting the transparent base sheet is a non-crystalline aromatic polyester resin having a glass transition temperature of 90 ° C. or higher, preferably 100 ° C. or higher. A non-crystalline aromatic polyester resin having a glass transition temperature of less than 90 ° C. is not preferable because of poor heat resistance.

  Furthermore, non-crystalline aromatic polyester resins having a glass transition temperature of 90 ° C. or higher are terephthalic acid, 1,4-cyclohexanedimethanol (CHDM), and 2,2,4,4-tetramethylcyclobutane-1,3. -Polycondensate of diol (TMCB). This non-crystalline aromatic polyester-based resin is a copolyester in which the dicarboxylic acid component and / or diol component of polyethylene terephthalate (PET) is partially replaced with another copolymer component to reduce or eliminate crystallinity. And even if it heat-molds frequently with a heating press etc., it does not cause the cloudiness by a crystallization and the fall of a melt | fusion property. The proportion of the copolymer component is at most 20 to 50 mol%. If the proportion of the copolymer component is too low, crystallinity appears in the polyester resin, the degree of crystallinity increases, and the tensile elongation at break and flexibility of the sheet decrease. This amorphous aromatic polyester-based resin is a polycondensate of approximately equimolar amounts of a dicarboxylic acid component and a diol component. As described above, the non-crystalline aromatic polyester-based resin having a glass transition temperature of 90 ° C. or more includes, for example, a diol component such as 1,4-cyclohexanedimethanol and 2,2,4,4-tetramethylcyclobutane-1, It can be produced by using 3-diol (TMCB).

  On the other hand, the crystalline polyester resin is a polycondensate of terephthalic acid and ethylene glycol, and the non-crystalline aromatic polyester resin (PETG) having a glass transition temperature of about 80 ° C. is one of the ethylene glycols. Part (about 30 mol%) is a polycondensate in which 1,4-cyclohexanedimethanol (CHDM) is substituted, and the non-crystalline aromatic polyester resin having a glass transition temperature of 90 ° C. or higher used in the present invention is The structure and manufacturing method are different.

  Films and sheets made of the above-described crystalline polyester resins are excellent in strength and heat resistance, but have anisotropy (because the film is formed from a T-die and stretched and crystallized in the winding direction (MD)). ). Therefore, there is a difference in strength between the winding direction (MD) and the T die width direction (TD). For that reason, when a film or sheet made of a crystalline polyester resin is heated, a large anisotropy occurs in the shrinkage of the film or sheet. In addition, because of its high crystallinity, it has inferior adhesion to other materials at temperatures below the melting point and has the property of being easily split in the crystal orientation axis direction. On the other hand, the non-crystalline aromatic polyester resin having a glass transition temperature of 90 ° C. or higher used in the present invention has a feature that these problems hardly occur.

  Furthermore, as an amorphous aromatic polyester system having a glass transition temperature of 90 ° C. or more, for example, Eastman Tritan copolyester FX100 and Eastman Tritan copolyester FX200 (both manufactured by Eastman Chemical Co., Ltd.) are commercially available. Can be mentioned. As long as the polyester is essentially non-crystalline and an aromatic polyester resin having a glass transition temperature of 90 ° C. or higher, other grades of commercial products and synthetic products can be used.

  In addition, although it is important that the transparent substrate sheet has high transparency, a resin, a filler, and the like that are usually blended in a sheet made of a transparent resin are added and blended within a range that does not hinder the transparency. There are no particular restrictions on this.

  Moreover, the thickness of a transparent base material sheet needs to be the range of 50-200 micrometers. When the total thickness of the transparent substrate sheet is less than 50 μm, vertical stripes and wrinkles are generated in the transparent substrate sheet during the coating and drying process of the ink receiving layer on the surface of such a relatively thin transparent substrate sheet. Not suitable for practical use. On the other hand, when the thickness of the transparent base sheet exceeds 200 μm, when such a thick transparent base sheet is used as an oversheet of a plastic IC card, the total thickness of the plastic IC card is regulated to around 760 μm by ISO. The thickness is greatly exceeded and is not practical. For example, in a non-contact type plastic IC card, oversheet (transparent) / core sheet (white, printed) / inlet sheet (sheet provided with IC chip + antenna) / core sheet (white, printed) / oversheet ( Taking a laminate of 5 layers as an example, the inlet sheet is generally 300 to 400 μm, and the core sheet (white, printed) cannot see the IC chip + antenna disposed on the inlet sheet ( In many cases, 150 to 300 μm is used. In such a case, if the total thickness of the transparent base sheet exceeds 200 μm, the total thickness of the non-contact plastic IC card greatly exceeds about 760 μm. Therefore, it is difficult to use in actual use and is not practical.

  Thus, by setting the thickness of the transparent base sheet to the desired range as described above, only the coating property and drying property of the vinyl chloride copolymer forming the ink receiving layer or the polyester resin having a functional group can be obtained. In addition, excellent properties such as sublimation direct thermal transfer printability, heat resistance, scratch resistance, chemical resistance, and heat-fusibility can be achieved.

[3] Ink receiving layer:
The ink receiving layer in the printing transparent sheet provided with the ink receiving layer of the present invention is formed in a layered manner on at least one side of the transparent substrate sheet. Further, the receiving layer is formed from a vinyl chloride copolymer or a polyester-based resin having a functional group, and is configured as a layer having a thickness of 1 to 20 μm. By forming in this way, color printing can be performed on the ink receiving layer provided on the transparent substrate sheet by, for example, a sublimation type direct thermal transfer method or a sublimation type indirect heat transfer method. Color-printed characters and designs have no color blurring or color distortion, and are excellent in density reproducibility. In addition, it is possible to form an ink receiving layer that adheres firmly to the transparent substrate sheet and does not peel off or change in quality. By using a transparent sheet for printing provided with such an ink-receiving layer, a predetermined color printing can be performed from a blank card using a sublimation direct thermal transfer printing machine, which is a general-purpose card printing machine, in the same manner as a PVC card. The plastic card which gave can be formed. This ink receiving layer is made of a vinyl chloride copolymer or a polyester-based resin having a functional group, and is applied on one side of the transparent substrate sheet with a solvent or water-based solution to a dry film thickness of 1 to 20 μm. It is made by processing.

  By providing such an ink receiving layer, there is no color blur, color distortion, excellent print reproducibility, excellent adhesion with a transparent substrate sheet, and characters, figures, symbols, etc. are not blurred It becomes clear and surely visible. Moreover, the ink receiving layer in the transparent sheet for printing of this invention is comprised as a layer which has a thickness of 1-20 micrometers. By providing such a desired thickness, the ink receiving layer does not need to be excessively thick. Furthermore, it can have sufficient printability and corresponds to the general thickness standard required for plastic cards. That is, when the ink receiving layer is within the above-described desired thickness range, it is possible to ensure the clarity of characters, figures, symbols, and the like when printed. On the other hand, if the thickness of the ink receiving layer is less than 1 μm, it is difficult to obtain sufficient printability. By reducing the adhesion between the ink-receiving layer and the transparent substrate sheet, for example, characters, designs, etc. by sublimation type direct thermal transfer system or sublimation type indirect thermal transfer system, color blurring or color distortion occurs, It becomes inferior in the reproducibility of density. On the other hand, when the thickness of the ink receiving layer exceeds 20 μm, when a heat-resistant transparent sheet provided with such an ink receiving layer is used for a plastic IC card, the transparent oversheet originally used for the plastic IC card is generally used. In addition, the total thickness of the heat-resistant transparent oversheet provided with the ink receiving layer is excessively thick with respect to about 50 to 125 μm. For example, in a plastic IC card, the thickness of the entire card is defined by ISO. Since it exceeds that, it is not preferable. Moreover, even if it is too thick, it is difficult to obtain printability commensurate with it.

  Here, the “ink-receiving layer made of a vinyl chloride copolymer or a polyester resin having a functional group” is transparent when coated on a transparent base sheet and has excellent fixability of printing ink. is there. The target printing method includes a sublimation type direct thermal transfer method or a sublimation type indirect heat transfer method, and various printing methods such as an ink jet method and an offset printing method can be targeted.

  The vinyl chloride copolymer has a copolymerization ratio between vinyl chloride and another monomer of at least 30% by mass of vinyl chloride and an average degree of polymerization of 100 to 2000, and the vinyl chloride copolymer other than vinyl chloride. The copolymerization component is one or more selected from vinyl esters, acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, olefins, acrylonitrile, styrene, vinylidene chloride, vinyl ethers, and aromatic vinyl compounds.

  On the other hand, the polyester-based resin having a functional group is a polyester-based resin having a sulfonate group or a carboxylate group, and is composed of a (water) solution using an organic solvent and water as a medium. By forming the ink receiving layer, it is possible to perform color printing with excellent sharpness and density because of excellent adhesion to the transparent substrate sheet and excellent fixability of the printing ink.

  The ratio (ratio) of vinyl chloride in the vinyl chloride copolymer is 30% by mass or more, preferably 50% by mass or more. This ratio is 30% by mass or more, preferably 50% by mass or more even in the case of binary copolymers and ternary or higher multi-component copolymers. Here, the vinyl chloride component contributes to fixing of printing ink (ink acceptance), and the other components contribute to solubility in organic solvents, dispersion stability of polymer droplets in water, and adhesion to the substrate. Therefore, by setting it to 30% by mass or more, especially by direct thermal transfer printing, it has excellent adhesion to a transparent substrate sheet, excellent color development and sharpness, characters, symbols, images, And color printing such as designs can be performed. On the other hand, when the ratio of the vinyl chloride structural unit is less than 30% by mass, it becomes difficult to obtain good printability. In addition, it is preferable that the upper limit of content of a vinyl chloride component is 85 mass%. If the vinyl chloride component content increases too much, the copolymer component content decreases and the solubility in organic solvents is inferior, resulting in inferior film formability during coating and adhesion to the substrate. Therefore, formation of the ink receiving layer on the substrate is hindered.

  The average degree of polymerization of the vinyl chloride copolymer forming the ink receiving layer is preferably 100 to 2000. An ink receiving layer containing a vinyl chloride copolymer having such an average degree of polymerization is excellent in printability and also has good adhesion to a transparent substrate sheet. Furthermore, if the average degree of polymerization is too low, such as less than 100, the cohesive force of the ink-receiving layer becomes small and the printed layer becomes brittle. On the other hand, a vinyl chloride copolymer having an average degree of polymerization exceeding 2000 is inferior in coating suitability because it is inferior in solubility in an organic solvent or in dispersion stability in water. In addition, the layer cannot be formed properly and does not function as an ink receiving layer.

  Here, the average degree of polymerization is a value representing how many monomers are polymerized to form a copolymer. The total number of molecules of vinyl chloride and the copolymer components other than vinyl chloride that form a vinyl chloride copolymer formed by polymerization of vinyl chloride and a copolymer component other than vinyl chloride is the number of molecules of the vinyl chloride copolymer. The value divided by. The average degree of polymerization refers to the number average degree of polymerization.

  Examples of the vinyl chloride copolymer forming the ink receiving layer include vinyl chloride-olefin copolymers such as vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride-isobutylene copolymer, and chloride. Halogenated olefins such as vinyl chloride-propylene copolymers such as vinyl-vinylidene chloride copolymers, vinyl chloride-vinyl fluoride copolymers, vinyl chloride-vinyl bromide copolymers, vinyl chloride-propylene chloride copolymers, etc. Copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl ester copolymer such as vinyl chloride-vinyl stearate copolymer, vinyl chloride-acrylic such as vinyl chloride-acrylic copolymer, or acrylic Derivative copolymer, ethylene-vinyl chloride-vinyl acetate copolymer, ethylene-vinyl chloride-acrylic acid Chill copolymer, methyl methacrylate - butadiene - styrene - may be mentioned 3-way, or quaternary copolymer of vinyl chloride copolymer. The copolymer structure of the vinyl chloride copolymer may be a block copolymer, a graft copolymer, or a random copolymer.

  On the other hand, examples of the polyester-based resin having a functional group include aqueous polyester-based resins containing a sulfonate group or a carboxylic acid group. Furthermore, these aqueous polyester-based resins and vinyl-based monomer emulsion polymerization emulsions, and these aqueous polyester-based resins are included. Dispersible water-dispersed resin composition of water and copolymer acrylic resin, mixed aqueous solution of these water-based polyester resins, water-based urethane resin and polyvinyl alcohol (hereinafter PVA), aqueous dispersion, or mixed aqueous solution of these, aqueous dispersion present Under mixing of an anionic graft polymer obtained by graft polymerization of a hydrophilic radical polymerizable vinyl monomer and another vinyl monomer, a vinyl copolymer having a side chain cationic quaternary ammonium base, and PVA Mixed aqueous solution with the resulting modified cationic polymer Aqueous dispersion, and the like.

  Examples of the sulfonate group, which is a functional group of the polyester resin, include groups in which protons of the sulfonate group are substituted with other cations (for example, metal ions, organic onium ions, etc.). Needless to say, is not limited to monovalent ions, but may be divalent or higher ions. Furthermore, examples of the carboxylate group include groups in which a hydrogen atom of a carboxyl group is substituted with another cation.

  The above-mentioned polyester-based resin having a sulfonate group can be obtained, for example, by polymerizing a polyester-based resin and then copolymerizing a dicarboxylic acid or glycol containing a sulfonate group such as a metal salt of sulfonic acid. A polyester resin having a carboxylate group can be obtained by a method in which an acid anhydride is reacted with a polyester resin, a carboxyl group is introduced, and then neutralized with an alkali compound or the like to obtain a carboxylate.

  Further, in order to perform suitable coating and drying on the substrate sheet, a coating agent (vinyl chloride copolymer or polyester resin having a functional group) for forming an ink receiving layer is used as an organic solvent solution, an aqueous solution or an organic solvent. Used as a mixed aqueous solution of solvent and water. By being configured as a solvent solution, an aqueous solution, or a mixed aqueous solution in this way, it becomes easy to apply a thin coating on the surface of the substrate when applying to the substrate sheet, and it is easy to adjust the thickness of the ink receiving layer. Become.

  An organic solvent that can be used by dissolving a copolymer or a polyester resin that forms an ink receiving layer containing a vinyl chloride copolymer or a polyester resin having a functional group is ethyl cellosolve (2-ethoxy). Ethanol), butyl cellosolve (2-n-butoxyethanol), ethyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, methyl ethyl ketone, isobutyl ketone, ethyl acetate, butyl acetate, isopropyl acetate, dioxane, cyclohexanone, and the like. The organic solvent is not limited to one type when used, and two or more types can be mixed and used.

  Further, as described above, the mixing ratio of the organic solvent and water when used as a mixed aqueous solution of the organic solvent and water is not particularly limited, and it is easy to adjust the thickness of the ink receiving layer. It is preferable to determine in consideration of thinness and the like.

  The copolymer or polyester resin forming the ink receiving layer is required to be used as an organic solvent solution or an aqueous solution as described above, and the solid content concentration at that time is 20 to 60% by mass. It is preferable to set it as the range. This is because if it is less than 20% by mass, several times of recoating are required to obtain a desired dry film thickness, and man-hours are required. On the other hand, if it exceeds 60% by mass, uniform coating becomes difficult.

  An agent for forming an ink receiving layer containing a vinyl chloride copolymer or a polyester-based resin having a functional group is applied to one side of a single-layer sheet, which will be described later, by a known coating method. Can be formed. For example, a method of preparing an ink receiving layer by preparing a coating solution dissolved or dispersed in a solvent or water, and applying and drying the adjusted coating solution by a known method such as gravure coating. it can.

  The drying temperature after coating is the same as the solvent used when applying a vinyl chloride copolymer or a polyester resin having a functional group to form a heat-resistant transparent ink sheet and an ink-receiving layer (organic solvent). Or water) depending on the species, but generally 60 to 120 ° C is preferable. Moreover, considering the damage due to the drying temperature of the base sheet as for the drying time, a long drying time is preferable at a relatively low temperature, but when considering industrial production, it is usually several tens of seconds to several tens of minutes. From less than 1 minute to several minutes is preferable from the viewpoint of productivity. By performing drying under such drying conditions, the ink receiving layer can be formed in close contact with the transparent substrate sheet. On the other hand, if the drying temperature after coating is less than 60 ° C., there is a problem in the drying property of the organic solvent or water of the vinyl chloride copolymer forming the ink receiving layer or the polyester resin having a functional group, and the ink receiving layer is organic. Since the solvent and water remain, the ink-receiving layer becomes sticky, or the cohesive force of the ink-receiving layer is greatly reduced and the function is greatly reduced, which is not suitable for practical use. On the other hand, when the drying temperature after coating exceeds 120 ° C., the evaporation of the organic solvent and water becomes violent, which may cause voids and cracks in the dried ink receiving layer. In addition, the transparent base sheet is softened, causing vertical stripes in the transparent base sheet, which is not preferable. The drying time depends on the drying temperature, but by setting the desired drying time as described above, a strong ink receiving layer without stickiness can be formed on the transparent substrate sheet. On the other hand, if the drying time is too short, it is necessary to increase the drying temperature more than necessary, which may cause voids and cracks in the dried ink-receiving layer, and may cause softening of the transparent substrate sheet. This is undesirable because it causes vertical streaks in the material sheet.

[4] Lubricant:
Moreover, in this embodiment, it is preferable to make a heat-resistant transparent sheet contain a lubricant. This is because inclusion of a lubricant can prevent fusion to the press plate during molding and heating. Examples of the lubricant include fatty acid esters, fatty acid amides, and fatty acid metal salts, and it is preferable to add at least one lubricant selected from them.

  Examples of the fatty acid ester lubricants include butyl stearate, cetyl palmitate, stearic acid monoglyceride, stearic acid diglyceride, stearic acid triglyceride, montan wax acid ester, wax ester, dicarboxylic acid ester, and complex ester. Examples of fatty acid amide-based lubricants include stearic acid amide and ethylene bisstearyl amide. Furthermore, examples of the fatty acid metal salt lubricant include calcium stearate, magnesium stearate, zinc stearate, aluminum stearate and barium stearate.

[5] Antioxidants, anti-coloring agents, ultraviolet absorbers, and light stabilizers:
Furthermore, in this embodiment, it is also preferable to contain at least one of an antioxidant and a coloring inhibitor, and at least one of an ultraviolet absorber and a light stabilizer as necessary. Addition (mixing) of at least one of an antioxidant and an anti-coloring agent effectively acts on physical property reduction and hue stabilization due to molecular weight reduction during molding processing. Here, a phenolic antioxidant or a phosphite ester colorant is used as at least one of the antioxidant and the colorant. Addition (mixing) of at least one of an ultraviolet absorber and a light stabilizer effectively acts to suppress light deterioration resistance during actual use as a plastic card. As such an ultraviolet absorber, a benzotriazole compound, a hydroxyphenyltriazine compound, a cyclic imino ester compound, or the like can be used. As said antioxidant, a phenolic antioxidant, an amine antioxidant, etc. can be used, for example.

  Examples of the phenol-based antioxidant include α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 3 -5-di-t-butyl-4-hydroxytoluene; pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- ( 3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2- t-butyl-6- (3′-t-butyl-5′-methyl-2′-hydroxybenzyl) -4-methylphenol Acrylate, 2,6-di-tert-butyl-4- (N, N-dimethylaminomethyl) phenol, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-methylenebis (2,6-di-tert-butylphenol), 2, 2′-methylenebis (4-methyl-6-cyclohexylphenol), 2,2′-dimethylene-bis (6-α-methyl-benzyl-4-cresol), 2,2′-ethylidene-bis (4,6- Di-t-butylphenol), 2,2'-butylidene-bis (4-methyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-) -Butylphenol), triethylene glycol-N-bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, 1,6-hexanediol bis [3- (3,5-di- t-butyl-4-hydroxyphenyl) propionate], bis [2-t-butyl-4-methyl 6- (3-t-butyl-5-methyl-2-hydroxybenzyl) phenyl] terephthalate, 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1, -dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5 ] Undecane, 4,4'-thiobis (6-t-butyl-m-cresol), 4,4'-thiobis (3-methyl-6-t-butylphenol), 2,2'-thiobi (4-methyl-6-tert-butylphenol), bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, 4,4′-di-thiobis (2,6-di-tert-butylphenol) 4,4′-tri-thiobis (2,6-di-t-butylphenol), 2,2-thiodiethylenebis- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] 2,4-bis (n-octylthio) -6- (4-hydroxy-3 ′, 5′-di-t-butylanilino) -1,3,5-triazine, N, N′-hexamethylenebis- ( 3,5-di-t-butyl-4-hydroxyhydrocinnamide), N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, 1,1 , 3-Tris (2-methyl -4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris (3 , 5-di-t-butyl-4-hydroxyphenyl) isocyanurate, tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris (3,5-di) -T-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 1,3,5-tris 2 [ 3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl isocyanurate and tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionyloxymethyl] methane, and the like.

  Among these examples, n-octadecyl-3- (3,5-di-t-butyl-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3, 5-di-t-butyl-4-hydroxybenzyl) benzene, 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, tetrakis [3- (3,5- Di-t-butyl-4-hydroxyphenyl) propionyloxymethyl] methane is preferred, and n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate is particularly preferred. The said hindered phenolic antioxidant can be used individually or in combination of 2 or more types.

  Examples of coloring inhibitors include phosphite compounds, such as triphenyl phosphite, tris (nonylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl. Monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, 2,2-methylenebis (4,6-di-t-butyl Phenyl) octyl phosphite, tris (diethylphenyl) phosphite, tris (di-iso-propylphenyl) phosphite, tris (di-n-butylphenyl) phosphite, tris (2,4-di t-butylphenyl) phosphite, tris (2,6-di-t-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite Bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-ethylphenyl) pentaerythritol diphosphite, phenylbisphenol A Examples thereof include pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, and dicyclohexyl pentaerythritol diphosphite.

  Furthermore, as another phosphite compound in the coloring inhibitor, those having a cyclic structure by reacting with dihydric phenols can be used. For example, 2,2′-methylenebis (4,6-di-t-butylphenyl) (2,4-di-t-butylphenyl) phosphite, 2,2′-methylenebis (4,6-di-t- Butylphenyl) (2-t-butyl-4-methylphenyl) phosphite, 2,2′-methylenebis (4-methyl-6-t-butylphenyl) (2-t-butyl-4-methylphenyl) phosphite And 2,2′-ethylidenebis (4-methyl-6-t-butylphenyl) (2-t-butyl-4-methylphenyl) phosphite.

  Among the anti-coloring agents described above, tris (2,4-di-t-butylphenyl) phosphite is particularly preferable because of its extremely high purity and excellent hydrolysis resistance and volatilization resistance. The phosphite ester coloration inhibitor may be used alone or in combination of two or more. Moreover, you may use together with a phenolic antioxidant.

  Specific examples of the above-described ultraviolet absorbers, which are benzotriazole compounds, hydroxyphenyltriazine compounds, and cyclic imino ester compounds, are as follows.

  First, examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole and 2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl). Benzotriazole, 2- (2′-hydroxy-3 ′, 5′-bis (α, α′-dimethylbenzyl) phenylbenzotriazole, 2,2′methylenebis [4- (1,1,3,3-tetramethyl) Butyl) -6- (2H-benzotriazol-2-yl) phenol], methyl-3- [3-t-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenylpropionate-polyethylene The compound represented by the condensate with glycol can be mentioned.

  Examples of the hydroxyphenyl triazine-based compound ultraviolet absorber include 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-hexyloxyphenol and 2- (4,6-bis). And (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -5-hexyloxyphenol.

  Furthermore, as the cyclic imino ester compound ultraviolet absorber, for example, 2,2′-p-phenylenebis (3,1-benzoxazin-4-one), 2,2′-2-phenylenebis (3,1- And benzoxazin-4-one) and 2,2′-4,4′-diphenylenebis (3,1-benzoxazin-4-one).

  Examples of the light stabilizer include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, tetrakis (2 , 2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2 , 3,4-Butanetetracarboxylate, poly {[6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl] [(2,2, 6,6-tetramethylpiperidyl) imino] hexamethylene [(2,2,6,6-tetramethylpiperidyl) imino]} and polymethylpropyl 3-oxy- [4- (2,2,6,6-tetra Methyl) pipette A hindered amine compound typified by [diynyl] siloxane can also be used, and such a light stabilizer has better performance in terms of weather resistance, etc. in combination with the ultraviolet absorber and optionally various antioxidants. Demonstrate.

  More preferably, the non-transparent base sheet contains 0.01 to 3 parts by mass of a lubricant with respect to 100 parts by mass of a transparent resin mainly composed of an amorphous aromatic polyester resin having a glass transition temperature of 90 ° C. or higher. Comprising a crystalline aromatic polyester-based resin composition, further comprising 0.1 to 5 parts by mass of at least one of an antioxidant and an anti-coloring agent with respect to 100 parts by mass of the non-crystalline aromatic polyester-based resin; and 0.1-5 mass parts of at least 1 sort (s) of a ultraviolet absorber and a light stabilizer are included.

  Here, the addition amount of the lubricant is 0.01 to 3 parts by mass, preferably 0.05 to 1.5 parts by mass. If it is less than 0.01 parts by mass, it will be fused to the press plate at the time of hot pressing, and if it exceeds 3 parts by mass, there will be a problem in interlayer heat fusion at the time of multi-layer heat-pressing of the card. Furthermore, if the addition amount of at least one of an antioxidant and an anti-coloring agent is less than 0.1 parts by mass, the thermal oxidation reaction of the amorphous aromatic polyester resin in the sheet molding step by melt extrusion molding, and Inconveniences such as thermal discoloration are likely to occur. On the other hand, if it exceeds 5 parts by mass, problems such as bleeding of these additives are likely to occur. Furthermore, when the addition amount of at least one of the ultraviolet absorber and the light stabilizer is less than 0.1 parts by mass, the effect is poor, and light defects such as deterioration due to light resistance and associated discoloration tend to occur. Furthermore, if it exceeds 5 parts by mass, problems such as bleeding of these additives are likely to occur, which is not preferable.

[6] Method for forming transparent substrate sheet:
In the present invention, for obtaining a transparent substrate sheet, for example, a method of melt extrusion molding a resin composition can be employed.

  Specifically, the resin composition is formed into pellets as necessary and charged into a melt extrusion molding machine with a T die, and a sheet melt-extruded from the T die at an extrusion temperature of 180 to 250 ° C. is predetermined with a multistage roll. After controlling the temperature, the sheet is cooled and solidified to produce a sheet having a predetermined thickness. In addition, the manufacturing method of the transparent base material sheet which has the heat resistance of this invention is not limited to the said method, It can form by a well-known method. For example, it can be obtained according to the description of JP-A-10-71763, pages (6) to (7).

[7] Total light transmittance:
Furthermore, the total light transmittance of the transparent substrate sheet is preferably 70% or more, and more preferably 85% or more. For example, when the printing transparent sheet on which the ink receiving layer of the present invention is formed is used for a laminate sheet for a plastic IC card, printing is generally performed for those uses. Therefore, when the printing transparent sheet on which the ink receiving layer of the present embodiment is formed is used as an oversheet of a plastic IC card, for example, printing of characters, figures, etc. is performed on a sheet (core sheet (white)) positioned below the sheet. Ink acceptance, which is the outermost layer, to produce a blank card by heating and laminating the printed core sheet (hereinafter, printing of a white sheet on which characters, figures, etc. have been printed, as appropriate) Since the transparent sheet for printing in which the layer is formed requires the visibility of the printing portion in the lower layer, the transparent sheet for printing in which the ink receiving layer is formed is required to have high transparency. For example, to give an example of a plastic IC card, there are five printing transparent sheets / core sheets (white) / inlets / core sheets (white) / ink transparent layers on which an ink receiving layer is formed. The sheets are stacked and heated and laminated with a vacuum press machine or the like, and then punched to produce a card (blank card). Then, after directly printing an image, characters, symbols, etc. on a blank card using a direct thermal transfer printer, it is usually coated with a protective coating to obtain a plastic IC card.

  As another example, a transparent sheet for printing / core sheet (printing) / inlet / core sheet in which fixed information is color-printed on one side of a core sheet (white) by offset printing or the like and then an ink receiving layer is formed. (Printing) / After stacking five sheets of transparent printing sheets on which an ink receiving layer is formed and heating and laminating them with a vacuum press machine or the like, punching is performed to produce a card (blank card). For example, personal information such as a person image is directly printed on a card using a thermal transfer printer, and then usually a protective coating is applied to obtain a plastic IC card.

  Here, the “total light transmittance” is an index indicating the ratio of light transmitted through the light incident on the sheet, film, film, etc., and the total light transmittance when all the incident light is transmitted is 100%. In this specification, “total light transmittance” indicates a value measured in accordance with JIS K7105 (light transmittance and total light reflectance). Measurement of this total light transmittance Can be measured using, for example, a Nippon Denshoku Industries haze meter (trade name: “NDH 2000”), a spectrophotometer (trade name “EYE7000” manufactured by Macbeth Co., Ltd.), and the like.

  The direct thermal transfer color printing system described above is a system in which a sublimation ink ribbon (dye system) is pressed against a blank card and heated to transfer the sublimation ink to the card surface, and then a protective transparent coating is applied. Processing can be performed by a single system. On the other hand, the indirect thermal transfer color printing method transfers a sublimation ink ribbon (pigment system) to a PET film according to the same principle as described above, and then affixes the PET film on which the sublimation ink has been transferred to a blank card or sublimation type. A method in which a PET film with ink transferred is pressed against a blank card and heated to transfer the sublimation ink to the card surface, and then a protective transparent coating is applied. The indirect thermal transfer color printing method is only clear for the ribbon of the ink ribbon, which is clear and clean, and is discarded. For each PET film to which the sublimation ink is transferred, the coloring is not very clear due to the pigment-based ink. In the method of affixing to a blank card, the PET film has a thickness of at least about 20 μm, so the thickness increases. There is. In the latter method of indirect thermal transfer color printing, the PET film that has been transferred once is discarded, and the process is considerably complicated and there is a problem in productivity.

[8] Colorant:
It is preferable to contain 1 part by mass or more of at least one kind of resin colorant such as dye or pigment with respect to 100 parts by mass of the polyester resin forming the transparent base sheet of the present invention. That is, as described above, the plastic IC card has a configuration of oversheet / core sheet / inlet sheet / core sheet / oversheet. Furthermore, it is common that an image or the like is fixedly printed on the core sheet by color printing using offset printing or the like. In light of the visibility of an image printed on the core sheet, light colors and particularly white are desirable.

  As coloring agents for resins such as coloring dyes and pigments, titanium oxide, barium oxide, zinc oxide as a white pigment, iron oxide, titanium yellow as a yellow pigment, iron oxide as a red pigment, cobalt blue ultramarine blue as a blue pigment, etc. Is mentioned. However, in order to improve the contrast, a light colored and lightly colored system is preferable.

  Among the coloring dyes and pigments, it is more preferable to add resin colorants such as white dyes and pigments, which stand out in contrast.

[9] For plastic cards:
Furthermore, the printing transparent sheet formed with the ink receiving layer in this embodiment can be suitably used for plastic cards.

  Here, as a plastic card to which the transparent sheet for printing formed by forming the ink receiving layer of the present invention can be applied, for example, various ID cards, health insurance cards, ETC cards and other transportation cards, bank cards, credits, etc. Various IC cards such as cards and various membership cards can be listed. However, these are merely examples, and the present invention is not limited to these.

  In general plastic IC cards, as described above, a general-purpose image or the like is color-printed on one side of the core sheet by offset printing or the like, and then the transparent sheet for printing formed by forming an ink receiving layer is overlaid. Used as a sheet, heated and laminated with an inlet sheet or the like, and then cut into a predetermined card size to produce a blank card. Thereafter, a method of performing color printing with a sublimation type direct thermal transfer system card printer is generally adopted. Further, a transparent sheet for printing formed with an ink receiving layer is used as an oversheet, and after heat lamination with a white core sheet (unprinted), an inlet sheet, etc., a white blank card is cut by cutting to a predetermined card size. To manufacture. Thereafter, a method of performing color printing with a sublimation type direct thermal transfer system card printer is generally adopted.

  As described above, direct thermal transfer color printing includes a method in which a sublimation ink ribbon (dye system) is pressed against a blank card and heated to transfer the sublimation ink to the card surface, and then a protective transparent coating is applied. On the other hand, indirect thermal transfer color printing, a sublimation ink ribbon (pigment system) is transferred to a PET film according to the same principle as described above, and then the PET film on which the sublimation ink is transferred is attached to a blank card, or the sublimation ink is There is a method of applying a protective transparent coating after the transferred PET film is pressed against a blank card and heated to transfer the sublimation ink onto the card surface. Direct thermal transfer color printing is clear and clean due to dye-based ink, and only the ribbon of the ink ribbon is discarded, while indirect thermal transfer color printing is not very clear due to pigment-based ink, Since the PET film has a thickness of at least about 20 μm in the method of pasting to the blank card for each PET film to which the sublimation ink has been transferred, the overall thickness increases, and the PET film once transferred will be discarded. There is also a problem as waste. On the other hand, a sublimation type direct thermal transfer color printer that has already been widely used in PVC cards is used by using the printing transparent sheet formed with the ink receiving layer of the present invention as an oversheet. In addition, there is no problem of discarding a large amount of PET film such as indirect thermal transfer color printing, and a desired color image can be printed on a card, so that the value of use can be greatly increased.

[10] Matting The transparent surface for printing formed by forming the ink receiving layer, the core sheet, and other sheet surfaces may be subjected to matting with an average roughness (Ra) of 0.1 to 5 μm. preferable. As described above, the reason why the mat processing is appropriately and selectively formed on each of the above-described sheet surfaces is that there is a step of performing color printing by offset printing on one side of the core sheet when the plastic card is heated and laminated. In this process, the sheet is transported by a conveyor and loaded into a printing machine. However, if the mat is not properly processed, the sheet does not slide and causes a problem in sheet transport. Further, other sheets similarly have problems in the transportability in the transport process, which hinders mass production. Further, in the step of heating and laminating a plurality of various sheets, there is a problem in that bubbles between the sheets are difficult to be removed and a “bulge” on the card surface is generated.

  When the average roughness (Ra) of the sheet surface is less than 0.1 μm, as described above, the sheet conveyance problem and the “bubble” problem during heating lamination occur, but the average roughness (Ra) of mat processing exceeds 5 μm. In the core sheet, there is a problem with printability, and in the oversheet, the mat processing on the sheet surface is not heated to a mirror surface in the heat lamination process, and it does not become a mirror surface. This is not preferable because the visibility is reduced.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In the following examples and comparative examples, “parts” and “%” mean parts by mass and mass% unless otherwise specified. Various evaluations and measurements in the examples were evaluated and measured by the following methods.

[1] Transparency of a transparent sheet for printing provided with an ink receiving layer:
For the transparent printing sheets E to T of Examples 1 to 6 and Comparative Examples 1 to 5, the total light transmittance of each sheet was measured using a spectrophotometer (trade name “NDH 2000” manufactured by Nippon Denshoku Industries Co., Ltd.). The transparency of the sheet was determined at the following evaluation level.
A: Total light transmittance of 80% or more, very good light transmission,
○: Total light transmittance of 60% or more and less than 80%, good light transmission,
X: The total light transmittance is less than 60%, and the light transmittance is inferior.

[2] Adhesion between ink receiving layer and transparent substrate sheet:
For the transparent sheets E to T for printing of Examples 1 to 6 and Comparative Examples 1 to 5, the adhesion between the ink receiving layer and the transparent substrate sheet was determined according to JIS K 5600 (cross-cut test (lattice pattern: 25 And the adhesion between the ink receiving layer and the substrate sheet was evaluated at the following evaluation levels.
A: No peeling at all, very good adhesion,
○: Within 5 peels, good adhesion,
Δ: Within 10 peels, adhesion is slightly good,
X: 10 to 20 peels, poor adhesion,
XX: All peeling and adhesion are very poor.

[3] Color printability:
Layers of oversheet / core sheet / core sheet / oversheet using the transparent sheets E to T for printing of Examples 1 to 6 and Comparative Examples 1 to 5 as oversheets, and the sheet B produced in Production Example 2 as a core sheet Using a rotary vacuum press machine (manufactured by Nissei Plastic Industry), pressing was performed at a heating temperature of 160 ° C. and a surface pressure of 10 MPa so that the total thickness was about 700 μm in a tact time of 2 minutes. A blank card was obtained by punching after pressing. These blank cards were subjected to color printing using a double-sided card printer (product name: PR5350, manufactured by Nisca Co., Ltd.), and the printing situation was observed with the naked eye and visually evaluated at the following evaluation levels.
○: No color blur or color skip, good color printing with slightly lighter density,
Δ: No color blur or color jump but low density, poor color printability
X: Color blur and color jump are observed, the density is extremely thin, and the color printability is extremely poor.

(Production Example 1) Single-layer sheet A: Transparent single-layer sheet 100 parts of non-crystalline aromatic polyester-based resin (trade name “Eastman Tritan copolymer FX100” manufactured by Eastman Chemical Co., Ltd., glass transition temperature 110 ° C.), as a lubricant Formulated with 0.1 parts of calcium stearate and processed with a T-die extruder so that the total sheet thickness is 100 μm and the average surface roughness (Ra) on both sides of the sheet is 0.5 to 1.8 μm. A single layer sheet A was obtained.

(Production Example 2) Single-layer sheet B: Transparent single-layer sheet Non-crystalline aromatic polyester-based resin (trade name “Eastman Tritan copolyester FX200” manufactured by Eastman Chemical Co., Ltd., glass transition temperature 119 ° C.) 100 parts, as a lubricant Formulated with 0.1 parts of calcium stearate and processed with a T-die extruder so that the total sheet thickness is 100 μm and the average surface roughness (Ra) on both sides of the sheet is 0.5 to 1.8 μm. A single-layer sheet B was obtained.

(Production Example 3) Single-layer sheet C: Transparent single-layer sheet Amorphous polyester-based resin (trade name “Eastar Copolyester 6763” manufactured by Eastman Chemical Co., Ltd., glass transition temperature 80 ° C.) 100 parts, calcium stearate as a lubricant 0.1 part is blended, and a single layer is formed by an extruder with a T die so that the total thickness of the sheet is 100 μm and the average surface roughness (Ra) on both sides of the sheet is 0.5 to 1.8 μm. Sheet C was obtained.

(Production Example 4) Single layer sheet D: White single layer sheet Amorphous polyester resin (trade name “Eastar Copolyester 6763” manufactured by Eastman Chemical Co., Ltd., glass transition temperature 80 ° C.) 100 parts, calcium stearate as lubricant 0.1 parts and 15 parts of titanium oxide are blended and processed with an extruder with a T die so that the total thickness of the sheet is 300 μm and the average surface roughness (Ra) on both sides of the sheet is 0.5 to 1.8 μm. To obtain a single layer sheet D.

  Using the transparent sheets of Production Examples 1 to 3 described above, transparent sheets E to R coated with a coating agent for forming an ink receiving layer were obtained.

[Example 1] (Transparent sheet E for printing having an ink-receiving layer)
As the base sheet, the single-layer sheet A (thickness: 100 μm) produced in Production Example 1 was used. Vinyl chloride-vinyl acetate copolymer (manufactured by Nissin Chemical Industry Co., Ltd., Solvain CN (vinyl chloride / vinyl acetate content = 89/11, polymerization degree = 750), ethyl cellosolve / butyl cellosolve / dioxane = 1/1 / 2 (mass ratio) was dissolved in a mixed solvent to prepare an ink receiving layer forming agent (coating liquid) having a solid content concentration of 20% using an automatic film applicator (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) After coating the coating liquid prepared above on one side of the single-layer sheet A, it was dried at a temperature of 110 ° C., and an ink receiving layer having an average coating thickness after drying of 6 to 8 μm was formed. Sheet E was obtained.

[Example 2] (Printing transparent sheet F formed with an ink receiving layer)
As the base sheet, the single-layer sheet A (thickness: 100 μm) produced in Production Example 1 was used. Vinyl chloride-vinyl acetate copolymer emulsion (Nissin Chemical Industry Co., Ltd., Viniblanc 603 (vinyl chloride / vinyl acetate content = 70/30, solid content concentration = 50%), ethyl cellosolve / butyl cellosolve = 1/1 An ink-receiving layer forming agent (coating solution) having a solid content concentration of 20% was prepared by diluting with a mixed solvent, and using the automatic film applicator (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), After coating the coating solution prepared above on one side of A, drying is performed at a temperature of 110 ° C. to obtain a transparent sheet F for printing on which an ink receiving layer having an average coating thickness of 6 to 8 μm after drying is formed. It was.

[Example 3] (Transparent sheet G for printing formed with an ink receiving layer)
As the base sheet, the single-layer sheet A (thickness: 100 μm) produced in Production Example 1 was used. Vinyl chloride-acrylic copolymer emulsion (manufactured by Nissin Chemical Industry Co., Ltd., Viniblanc 690 (vinyl chloride / acrylic content = 80/20, solid content concentration = 54%), ethyl cellosolve / butyl cellosolve = 1/1 ( (Mass ratio) The mixture was diluted with a mixed solvent to prepare an ink-receiving layer forming agent (coating solution) having a solid content concentration of 20%, using an automatic film applicator (manufactured by Yasuda Seiki Seisakusho Co., Ltd.). After coating the coating liquid prepared above on one side of the sheet A, the printing transparent sheet G formed with an ink receiving layer having an average coating thickness of 6 to 8 μm after drying at a temperature of 110 ° C. Obtained.

Example 4 (Printing transparent sheet H formed with an ink receiving layer)
As the base sheet, the single-layer sheet A (thickness: 100 μm) produced in Production Example 1 was used. Ethylene-vinyl chloride-vinyl acetate copolymer emulsion (manufactured by Sumika Chemtex Co., Ltd., Sumikaflex S-830 (ethylene / vinyl chloride / vinyl acetate content = 20/50/30, solid content concentration = 50%)) Then, diluted with a mixed solvent of ethyl cellosolve / butyl cellosolve = 1/1 (mass ratio) to prepare an ink-receiving layer forming agent (coating solution) having a solid content concentration of 20% Automatic film applicator (Yasuda Seiki Co., Ltd.) After the coating solution prepared above was applied to one side of the single-layer sheet A using a manufacturing method, the ink was received at a temperature of 110 ° C., and the average coating thickness after drying was 6 to 8 μm. The transparent sheet H for printing in which the layer was formed was obtained.

Example 5 (Printing transparent sheet J formed with an ink receiving layer)
As the base sheet, the single-layer sheet A (thickness: 100 μm) produced in Production Example 1 was used. Application of sulfonic acid group-containing polyester resin solution (manufactured by Takamatsu Yushi Co., Ltd., Pesresin A-1120, isopropyl alcohol 26 wt% / n-propyl alcohol 12 wt% / water 42 wt% mixed solvent, solid content concentration = 20%) The coating liquid prepared above was applied to one side of the single-layer sheet A using Ta (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), then dried at a temperature of 110 ° C., and the average coating thickness after drying Obtained a transparent sheet J for printing on which an ink receiving layer having a thickness of 6 to 8 μm was formed.

[Example 6] (Transparent transparent sheet K formed with an ink receiving layer)
As the base sheet, the single-layer sheet B (thickness: 100 μm) produced in Production Example 2 was used. Vinyl chloride-vinyl acetate copolymer (manufactured by Nissin Chemical Industry Co., Ltd., Solvain CN (vinyl chloride / vinyl acetate content = 89/11, polymerization degree = 750), ethyl cellosolve / butyl cellosolve / dioxane = 1/1 / 2 (mass ratio) was dissolved in a mixed solvent to prepare an ink receiving layer forming agent (coating liquid) having a solid content concentration of 20% using an automatic film applicator (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) After coating the coating liquid prepared above on one side of the single-layer sheet A, it was dried at a temperature of 110 ° C., and an ink receiving layer having an average coating thickness after drying of 6 to 8 μm was formed. Sheet K was obtained.

[Comparative Example 1] (Transparent transparent sheet P formed with an ink receiving layer)
As the base sheet, the single-layer sheet A (thickness: 100 μm) produced in Production Example 1 was used. Water-dispersed polyester resin (manufactured by Toyobo Co., Ltd., Vironal MD-1200 (solid content concentration 34%, butyl cellosolve 11%) is used with the above-mentioned monolayer base using an automatic film applicator (manufactured by Yasuda Seiki Seisakusho Co., Ltd.). After coating on one side of the material sheet A, it was dried at a temperature of 110 ° C. to obtain a transparent printing sheet P on which an ink receiving layer having an average coating thickness after drying of 6 to 8 μm was formed.

[Comparative Example 2] (Transparent transparent sheet Q formed with an ink receiving layer)
As the base sheet, the single-layer sheet A (thickness: 100 μm) produced in Production Example 1 was used. Acrylic emulsion (Takamatsu Oil & Fat Co., Ltd., prototype SNX-25 (solid content concentration 37%) is diluted by adding a mixed solvent of ethyl cellosolve / butyl cellosolve 1/1 (mass ratio), and coating with a solid content concentration of 22% Using an automatic film applicator (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), the coating solution was coated on one side of the single-layer sheet A, dried at a temperature of 110 ° C., and the average coating film after drying. A transparent sheet for printing Q having an ink receiving layer having a thickness of 6 to 8 μm was obtained.

[Comparative Example 3] (Printing transparent sheet R formed with an ink receiving layer)
As the base sheet, the single-layer sheet A (thickness: 100 μm) produced in Production Example 1 was used. After adjusting the vinyl chloride polymer emulsion (Nissin Chemical Industry Co., Ltd., VINYBRAN 985 (solid content concentration 37%) by adding ethyl cellosolve / butyl cellosolve = 1/1 mixed solvent to a solid content concentration of 22%. The coating liquid was coated on one side of the single-layer sheet A using an automatic film applicator (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), then dried at a temperature of 110 ° C., and the average coating film after drying A transparent sheet for printing on which an ink receiving layer having a thickness of 6 to 8 μm was formed was obtained.

[Comparative Example 4] (Transparent sheet S for printing formed with an ink receiving layer)
As the base sheet, the single-layer sheet C (thickness: 100 μm) produced in Production Example 3 was used. Vinyl chloride-vinyl acetate copolymer (manufactured by Nissin Chemical Industry Co., Ltd., Solvain CN (vinyl chloride / vinyl acetate content = 89/11, polymerization degree = 750), ethyl cellosolve / butyl cellosolve / dioxane = 1/1 / 2 (mass ratio) was dissolved in a mixed solvent to prepare an ink receiving layer forming agent (coating liquid) having a solid content concentration of 20% using an automatic film applicator (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) After coating the coating liquid prepared above on one side of the single-layer sheet A, printing is performed by drying at a temperature of 110 ° C. to form an ink receiving layer having an average coating thickness of 6 to 8 μm after drying. A transparent sheet S was obtained.

[Comparative Example 5] (Ink receiving layer non-transparent heat-resistant sheet, printing transparent sheet T)
As the base sheet, the single-layer sheet A (thickness 100 μm) produced in Production Example 1 was used as it was.

  Various evaluations were performed with the transparent printing sheets E to H and J to K obtained in Examples 1 to 6 described above. The results are shown in Table 1. Moreover, various evaluation was performed about the transparent sheets PT for printing obtained in Comparative Examples 1-5. The results are shown in Table 2.

(Discussion)
As shown in Tables 1 and 2, the printing transparent sheet formed with the ink receiving layers in Examples 1 to 6 has high total light transmittance and excellent transparency, and the ink receiving layer and the base sheet It was excellent in adhesion. Furthermore, in sublimation type direct thermal transfer color printing, it was confirmed that there was no color blurring and color distortion, a sufficient density, and good printability. On the other hand, the printing transparent sheet of Comparative Example 1 has high total light transmittance, excellent transparency, and excellent adhesion between the ink receiving layer and the substrate sheet. Blur and color distortion were observed, the density was insufficient, and the color printability was poor. Further, the transparent sheet for printing of Comparative Example 2 was inferior in color printability although it had good transparency and adhesion between the ink receiving layer and the base sheet. In the transparent sheet for printing of Comparative Example 3, the adhesion between the ink receiving layer and the substrate sheet was extremely poor, and the ink receiving layer was not formed on the substrate sheet. The transparent sheet for printing of Comparative Example 4 was poor in heat resistance of the base material sheet, and innumerable “wrinkles” were generated on the sheet in the coating / drying process of the ink receiving layer, and was inferior in practicality. Further, Comparative Example 5 is an example in which the ink receiving layer is not formed on the substrate, and is inferior in color printability.

  The present invention is a transparent sheet for printing excellent in heat resistance formed by an ink receiving layer capable of color printing excellent in color development and sharpness by sublimation type thermal transfer printing, and can be applied to a plastic card or the like. .

Claims (6)

A transparent sheet for printing provided with an ink receiving layer on at least one side of a transparent substrate sheet,
The transparent base sheet is composed of a non-crystalline aromatic polyester resin having a glass transition temperature of 90 ° C. or more, and is configured as a sheet having a thickness of 50 to 200 μm and a total light transmittance of 70% or more,
The ink receiving layer is made of a vinyl chloride copolymer or a polyester-based resin having a functional group, and a dry film thickness is 1 to 20 μm on one side of the transparent substrate sheet with a solvent or a solution using water as a medium. The transparent sheet for printing comprised as a layer which has thickness.   The transparent base sheet comprises a non-crystalline aromatic polyester resin composition comprising 100 parts by mass of a non-crystalline aromatic polyester resin having a glass transition temperature of 90 ° C. or more, and 0.01 to 3 parts by mass of a lubricant, The transparent sheet for printing according to claim 1, comprising 0.1 to 5 parts by mass of an antioxidant and / or an anti-coloring agent and 0.1 to 5 parts by mass of an ultraviolet absorber and / or a light stabilizer. .   3. The transparent printing material according to claim 1, wherein the vinyl chloride copolymer has a copolymerization ratio of vinyl chloride and another monomer of at least 30% by mass of vinyl chloride and an average degree of polymerization of 100 to 2000. 4. Sheet.   Copolymerization components other than vinyl chloride of the vinyl chloride copolymer are vinyl ester, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, olefin, acrylonitrile, styrene, vinylidene chloride, vinyl ether, and aromatic vinyl compound. The transparent sheet for printing according to any one of claims 1 to 3, which is one or more selected.   The transparent sheet for printing according to claim 1 or 2, wherein the polyester-based resin having the functional group is a polyester-based resin having a sulfonate group or a carboxylate group.   The transparent sheet for printing according to any one of claims 1 to 5, which is used for a plastic card.