JP2012187853A - Thermal transfer recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer recording medium which exhibits high transfer sensitivity in printing at high speed to reduce a dye to be used for a dye layer, and which prevents abnormal transfer in printing even after storage at high temperature and high humidity.SOLUTION: The thermal transfer recording medium includes a heat-resistant lubricative layer 40 formed on one surface of a base material 10, and a foundation layer 20 and the dye layer 30 successively formed on the other surface of the base material 10. The foundation layer 20 contains as main components: at least one of alkoxide, its hydrolytic product, and tin chloride; vinyl pyrrolidone/vinyl caprolactam copolymer; a water-soluble polymer; and water-dispersible polyester.

Description

  The present invention relates to a thermal transfer recording medium used in a thermal transfer type printer, and is provided with a heat-resistant slipping layer on one surface of a substrate, and an undercoat layer and a dye layer on the other surface of the substrate. Are sequentially formed. More specifically, the transfer sensitivity is high during high-speed printing, that is, the amount of dye used in the dye layer can be reduced, and abnormal transfer in printing can be prevented even after storage under high temperature and high humidity. Image quality that occurs at the edges, that is, the hue of the transfer layer is fused to the heat-sensitive transfer recording medium, resulting in partial matting of the surface of the printed material. The present invention relates to a thermal transfer recording medium capable of reducing the phenomenon.

  In general, a thermal transfer recording medium is an ink ribbon called a thermal ribbon, which is used in a thermal transfer type printer, and has a thermal transfer layer on one side of the substrate and heat resistance on the other side of the substrate. A slipping layer (back coat layer) is provided. Of these, the thermal transfer layer is an ink layer that is sublimated (sublimation transfer method) or melted (melt transfer method) by the heat generated in the thermal head of the printer, and transferred to the transfer target side. is there.

  Currently, among the thermal transfer systems, the sublimation transfer system can easily form full-color images with various functions of the printer, so digital camera self-prints, cards such as identification cards, amusement output, etc. Widely used. In addition, with the diversification of applications, there is a growing demand for miniaturization, high speed, low cost, and durability for the resulting prints. In recent years, the durability of prints on the same side of the base sheet is increasing. 2. Description of the Related Art Thermal transfer recording media having a plurality of thermal transfer layers provided so as not to overlap a protective layer or the like that imparts properties have become quite popular.

  As the image receiving sheet on the transfer target side, a solvent type image receiving sheet having a solvent type dye receiving layer and a water type image receiving sheet having an aqueous dye receiving layer are known. The solvent-based image-receiving sheet is superior to the water-based image-receiving sheet in terms of releasability between the dye layer and the dye-receiving layer, but the glossiness is low. Furthermore, solvent-based image-receiving sheets have a strong irritating odor, which causes health damage when sucked into the human body, and tends to be avoided from use due to problems such as environmental impact due to treatment of waste liquids and the like.

  In recent years, along with the diversification and widespread use of applications, there has been a problem that sufficient print density cannot be obtained with conventional thermal transfer recording media as the printing speed of printers increases. Therefore, in order to increase the transfer sensitivity, attempts have been made to improve the transfer sensitivity in printing by reducing the thickness of the thermal transfer recording medium. There is a problem that “wrinkles” occur and in some cases breakage occurs.

  In addition, attempts have been made to increase the printing density and transfer sensitivity in printing by increasing the dye / resin (Dye / Binder) ratio in the dye layer of the thermal transfer recording medium. In addition to being up, a part of the dye migrates to the heat-resistant slipping layer of the thermal transfer recording medium during the winding state in the manufacturing process (setback), and when the rewinding is performed, the migrated dye has another color. When the dye layer or the protective layer is re-transferred (backside back) and the contaminated layer is thermally transferred to the transfer target, the hue becomes different from the designated color, or so-called scumming occurs.

  Furthermore, an attempt has been made to increase the energy at the time of image formation on the printer side, not on the thermal transfer recording medium side, but not only the power consumption is increased, but besides shortening the life of the thermal head of the printer, The dye layer and the transfer target are fused, so that so-called abnormal transfer is likely to occur. On the other hand, when a large amount of a release agent is added to the dye layer or the transfer target in order to prevent abnormal transfer, blurring of the image or background staining may occur.

  Furthermore, when an image is formed by combining a heat-sensitive transfer recording medium and an image-receiving sheet having an aqueous dye-receiving layer (hereinafter referred to as “receiving layer”), the water-based receiving layer and the thermal transfer sheet cause thermal fusion, As a result, so-called “shine” occurs in which the surface of the printed material is partially matted.

  In order to solve such a demand, several methods have been proposed. For example, Patent Document 1 proposes a thermal transfer sheet having an adhesive layer containing a polyvinylpyrrolidone resin and a modified polyvinylpyrrolidone resin between a base material and a dye layer.

  Patent Document 2 proposes a thermal transfer sheet having an adhesive layer composed of a thermoplastic resin of polyvinyl pyrrolidone resin or polyvinyl alcohol resin and colloidal inorganic pigment ultrafine particles between a substrate and a dye layer.

JP-A-2005-231354 JP 2006-150956 A

  However, in the thermal transfer recording medium proposed in Patent Document 1, when printing is performed using a high-speed printer of the recent sublimation transfer method, abnormal transfer including that stored under high temperature and high humidity is not performed. Although not confirmed, there is a problem that the transfer sensitivity in printing is low, it does not reach a sufficient level, and “shine” cannot be sufficiently suppressed.

  In addition, the thermal transfer recording medium proposed in Patent Document 2 was printed in the same manner. As a result, although the transfer sensitivity in printing was high and reached a sufficient level, it was stored under high temperature and high humidity. Abnormal transcription was confirmed, and “shine” was also confirmed.

  As described above, the thermal transfer recording medium according to the prior art has high transfer sensitivity in printing, and does not cause abnormal transfer even when stored at high temperature and high humidity, making it a high-speed printer that has sufficiently improved the phenomenon of “shine”. It has a problem that it is difficult to deal with.

  The present invention has been made in view of the above problems, and has high transfer sensitivity during high-speed printing, that is, it can reduce the dye used in the dye layer, and can be printed even after storage under high temperature and high humidity. In addition, the image quality defect occurring in the high density portion can be prevented, that is, the hue fluctuation occurs due to the receiving layer of the transfer material being fused to the thermal transfer recording medium, and as a result, the surface of the print is partially It is an object of the present invention to provide a heat-sensitive transfer recording medium that can reduce the phenomenon of so-called “shine” that is matted.

  The invention according to claim 1 is a thermal transfer image-receiving sheet in which an aqueous receiving layer containing an aqueous binder and a release agent is formed on a substrate via an aqueous hollow particle layer containing an aqueous binder and hollow particles. A thermal transfer recording medium for forming an image by thermal transfer, wherein a heat-resistant slipping layer is provided on one surface of the substrate, and an undercoat layer and a dye layer are sequentially formed on the other surface of the substrate, The undercoat layer includes at least one of an alkoxide, a hydrolyzate thereof, and tin chloride, a vinylpyrrolidone-vinylcaprolactam copolymer, a water-soluble polymer, and a water-dispersible polyester as main components. To do.

  The invention according to claim 2 is the thermal transfer recording medium, wherein the water-soluble polymer is polyvinyl alcohol.

  The invention according to claim 3 is characterized in that the water-dispersible polyester is copolymerized with at least an ester-forming sulfonic acid alkali metal salt compound as a dicarboxylic acid component and copolymerized with diethylene glycol as a diglycol component. It is a thermal transfer recording medium.

  The invention according to claim 4 is the thermal transfer recording medium, wherein the alkoxide is tetraethoxysilane, triisopropoxyaluminum, or a mixture thereof.

The invention according to claim 5 is the thermal transfer recording medium, wherein the coating amount of the undercoat layer after drying is in the range of 0.10 g / m ^{2 to} 0.30 g / m ^2. .

  According to the present invention, the undercoat layer is mainly composed of at least one of an alkoxide, a hydrolyzate thereof, and tin chloride, a vinylpyrrolidone-vinylcaprolactam copolymer, a water-soluble polymer, and a water-dispersible polyester. As a result, the transfer sensitivity during high-speed printing is high, the amount of dye used in the dye layer can be reduced, and abnormal transfer in printing can be prevented even after storage under high temperature and high humidity. It is possible to obtain a sufficiently satisfactory print with little phenomenon.

  The polyester of the undercoat layer has excellent adhesion to the substrate and the dye layer, and the compatibility with the water-soluble polymer is improved by introducing an ester-forming alkali metal salt of sulfonic acid and diethylene glycol. Moreover, the tolerance with respect to organic solvents, such as MEK, toluene, and xylene, is acquired.

  Furthermore, the vinyl pyrrolidone-vinyl caprolactam copolymer of the undercoat layer has good adhesion between the base material and the dye layer after being stored at high temperature and high humidity, and has a high density part "Tecari" during high-speed printing. The ability to reduce the amount can be demonstrated.

  Further, the alkoxide of the undercoat layer and / or its hydrolyzate or tin chloride is a highly reactive inorganic component, and itself undergoes a polycondensation reaction while being dried from an aqueous solution to form a chain or tertiary. In addition to forming a polymer having an original structure, it forms a complex at the molecular level with a water-soluble polymer. Therefore, the alkoxide of the undercoat layer and / or the hydrolyzate thereof or the polycondensate of tin chloride improves the transfer sensitivity at the time of high-speed printing, which is insufficient with a water-soluble polymer alone. Polyester, alkoxide and / or its hydrolyzate or tin chloride complex with water-soluble polymer and vinylpyrrolidone-vinylcaprolactam copolymer is abnormal after storage at high temperature and high humidity, which is inferior to water-soluble polymer alone Provides improvements in terms of transcription and “shine”.

Further, the water-soluble polymer is polyvinyl alcohol, the water-dispersible polyester is at least an ester-forming alkali metal sulfonate compound as a dicarboxylic acid component, a copolymer obtained by copolymerizing diethylene glycol as a diglycol component, and the alkoxide. By using tetraethoxysilane or triisopropoxyaluminum, or a mixture thereof, the coating amount after drying of the undercoat layer is within the range of 0.10 g / m ² or more and 0.30 g / m ² or less, thereby enabling high speed printing. A high-sensitivity print can be obtained, and a higher-density print can be obtained, and there is no abnormal transfer in the print even after storage at high temperature and high humidity, so that a sufficiently satisfactory print can be obtained.

1 is a side sectional view showing a main part of a thermal transfer recording medium according to an embodiment of the present invention.

  A thermal transfer recording medium according to an embodiment of the present invention will be described below with reference to the drawings.

  That is, in the thermal transfer recording medium according to the embodiment of the present invention, a heat-resistant slipping layer is provided on one surface of a substrate, and an undercoat layer and a dye layer are sequentially formed on the other surface of the substrate. Of these, the undercoat layer contains at least one of an alkoxide, a hydrolyzate thereof, and tin chloride, a vinylpyrrolidone-vinylcaprolactam copolymer, a water-soluble polymer, and a water-dispersible polyester as main components.

  Here, the main component means that the water-soluble polymer, vinylpyrrolidone-vinylcaprolactam copolymer, water-dispersible polyester, alkoxide and / or a hydrolyzate thereof, or the like, as long as the effects of the present invention are not impaired. In addition to at least one of tin chloride, it represents that other components may be added, and the water-soluble polymer, vinylpyrrolidone-vinylcaprolactam copolymer, water-dispersible polyester, and alkoxide Or / and its hydrolyzate or tin chloride at least one of the total is meant to be contained in an amount of more than 50% by mass as viewed from the whole when the undercoat layer is formed, but preferably 80% by mass or more.

  FIG. 1 shows an essential part of a thermal transfer recording medium according to an embodiment of the present invention. A heat-resistant slipping layer 40 for imparting slipperiness with a thermal head is provided on one surface of a substrate 10. And the other surface of the substrate 10 includes at least one of alkoxide, a hydrolyzate thereof, and tin chloride, a vinylpyrrolidone-vinylcaprolactam copolymer, a water-soluble polymer, and a water-dispersible polyester as main components. The undercoat layer 20 and the dye layer 30 formed by applying and drying the coating solution are sequentially formed.

  Since the base material 10 is required to have heat resistance and strength not to be softened and deformed by heat pressure in thermal transfer, for example, polyethylene terephthalate, polyethylene naphthalate, polypropylene, cellophane, acetate, polycarbonate, polysulfone, polyimide, polyvinyl alcohol, aromatic Can be used as a composite of synthetic resin films such as polyamido polyamide, aramid, and polystyrene, and papers such as condenser paper and paraffin paper, either alone or in combination. In view of the above, a polyethylene terephthalate film is preferable. In addition, the thickness is in the range of 2 to 50 μm in consideration of operability and workability, but in consideration of handling properties such as transfer suitability and workability, the thickness is about 2 to 9 μm. preferable.

Further, in the base material 10, it is possible to perform an adhesion treatment on the surface on which the heat resistant slipping layer 40 and / or the undercoat layer 20 is formed. As the adhesion treatment, known techniques such as corona treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, roughening treatment, plasma treatment, primer treatment, etc. can be applied, and these treatments are used in combination. You can also In the present invention, it is effective to increase the adhesion between the substrate and the undercoat layer, and a primer-treated polyethylene terephthalate film is preferable from the viewpoint of cost. Next, the heat-resistant slipping layer 40 can be handled by a conventionally known layer. For example, a resin serving as a binder, a functional additive imparting releasability or slipperiness, a filler, a curing agent, a solvent, and the like are blended. And can be formed by coating and drying. The coating amount after drying of the heat resistant slipping layer is suitably about 0.1 to 2.0 g / m ² .

  As an example of the heat-resistant slip layer 40, the binder resin may be polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride-vinyl acetate copolymer, polyether resin, polybutadiene resin, acrylic polyol, polyurethane acrylate. , Polyester acrylate, polyether acrylate, epoxy acrylate, nitrocellulose resin, cellulose acetate resin, polyamide resin, polyimide resin, polyamideimide resin, polycarbonate resin and the like. Functional additives include natural waxes such as animal waxes and plant waxes, synthetic hydrocarbon waxes, aliphatic alcohols and acid waxes, fatty acid esters and glycerite waxes, synthetic ketone waxes, amine and amide waxes Synthetic waxes such as chlorinated hydrocarbon waxes and alpha-olefin waxes, higher fatty acid esters such as butyl stearate and ethyl oleate, sodium stearate, zinc stearate, calcium stearate, potassium stearate, magnesium stearate, etc. Surfactants such as higher fatty acid metal salts, long chain alkyl phosphate esters, polyoxyalkylene alkyl aryl ether phosphate esters or phosphate esters such as polyoxyalkylene alkyl ether phosphate esters, etc. Rukoto can. As fillers, talc, silica, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, kaolin, clay, silicone particles, polyethylene resin particles, polypropylene resin particles, polystyrene resin particles, polymethyl methacrylate resin particles, polyurethane resin particles, etc. Can be mentioned. Examples of the curing agent include isocyanates such as tolylene diisocyanate, triphenylmethane triisocyanate, tetramethylxylene diisocyanate, and derivatives thereof, but the above are not particularly limited.

  The undercoat layer 20 is, as an essential component of the present invention, at least one of vinylpyrrolidone-vinylcaprolactam copolymer, water-soluble polymer, water-dispersible polyester, alkoxide and / or a hydrolyzate thereof, and tin chloride. 1 as a main component.

  Examples of the water-soluble polymer include polyvinyl alcohol, polyvinyl pyrrolidone, starch, gelatin, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, sodium alginate and the like. Among these, polyvinyl alcohol and polyvinyl pyrrolidone are preferable, and polyvinyl alcohol is more preferable. Polyvinyl alcohol as used herein is generally obtained by saponifying polyvinyl acetate, and so-called completely saponified polyvinyl alcohol in which only several percent of acetate groups remain from so-called partially saponified polyvinyl alcohol in which dozens of acetate groups remain. It includes up to saponified polyvinyl alcohol and is not particularly limited.

  The vinylpyrrolidone-vinylcaprolactam copolymer is a copolymer of an N-vinylpyrrolidone monomer and vinylcaprolactam which is a vinyl polymerizable monomer. The form of copolymerization is not limited to any of random copolymerization, block copolymerization, and graft copolymerization. Here, the N-vinyl pyrrolidone-based monomer refers to N-vinyl pyrrolidone (N-vinyl-2-pyrrolidone, N-vinyl-4-pyrrolidone, etc.) and derivatives thereof. Examples of those having a substituent on the pyrrolidone ring such as vinyl-3-methylpyrrolidone, N-vinyl-5-methylpyrrolidone, N-vinyl-3-benzylpyrrolidone, N-vinyl-3,3,5-trimethylpyrrolidone However, it is not particularly limited.

  As an example of the water-dispersible polyester, the dicarboxylic acid component which is a copolymerization component has an ester-forming sulfonic acid alkali metal salt compound as an essential component, phthalic acid, terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, Aromatic dicarboxylic acids such as 2,5-dimethylterephthalic acid, 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, orthophthalic acid, and aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid Examples thereof include acids and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid.

  As the dicarboxylic acid component other than the ester-forming sulfonic acid alkali metal salt compound, an aromatic dicarboxylic acid is preferable, and since the aromatic nucleus of the aromatic dicarboxylic acid has a high affinity with a hydrophobic plastic, adhesion is improved, There is an advantage that it is excellent in degradability. In particular, terephthalic acid and isophthalic acid are preferable. The ester-forming sulfonic acid alkali metal salt compound is preferably contained in the total acid component in an amount of 6 to 20 mol%. More preferably, it is 10-18 mol%. When the ester-forming sulfonic acid alkali metal salt compound is less than 6 mol%, the dispersion time of the resin in water becomes long, and the solvent resistance is not sufficient. Conversely, if it exceeds 20 mol%, the water resistance tends to decrease.

  Examples of the ester-forming sulfonic acid alkali metal salt compound include alkali metal salts such as sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalenic acid-2,7-dicarboxylic acid (alkali sulfonic acid alkali). Metal salts) and their ester-forming derivatives, and the sodium salt of 5-sulfoisophthalic acid and its ester-forming derivatives are more preferably used.

  Examples of the diglycol component include diethylene glycol and aliphatic having 2 to 8 carbon atoms or alicyclic glycol having 6 to 12 carbon atoms. Specific examples of the aliphatic having 2 to 8 carbon atoms or the alicyclic glycol having 6 to 12 carbon atoms include ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, Neopentyl glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, 1,6-hexanediol , P-xylylene glycol, triethylene glycol and the like, and one or more of these may be used in combination. It is preferable to contain 20-80 mol% of diethylene glycol in the total glycol component. Even if diethylene glycol is outside this range, the solvent resistance to alcohol can be obtained, but the solvent resistance is insufficient with respect to aromatic solvents such as toluene and xylene.

The water-dispersible polyester is produced by a polycondensation reaction after esterification or transesterification of dicarboxylic acid and diglycol by a known production technique, but the production method is not limited at all. As an example of the alkoxide, tetraethoxysilane [Si (OC2 H5) 4], triisopropoxyaluminum _{[Al (O-C 3 H 7} ) 3 ] (- C ₃ H ₇ are isopropyl group) following general such It can be expressed by a formula. Among these, tetraethoxysilane or triisopropoxyaluminum is preferable because it is relatively stable even in an aqueous solvent.

General formula: M (OR) n
(M: metal element such as Si, Ti, Al, Zr,
R: alkyl group such as CH3, C2H5, n: oxidation number of metal element)
The tin chloride may be stannous chloride (SnCl2), stannic chloride (SnCl3), or a mixture thereof, and may be used as an anhydride or a hydrate.

The coating amount after drying of the undercoat layer 20 is not generally limited, but is preferably in the range of 0.10 g / m ² or more and 0.30 g / m ² or less. If it is less than 0.10 g / m ² , the transfer sensitivity at the time of high-speed printing may be insufficient due to deterioration during lamination of the dye layer, or there may be a problem with adhesion to the substrate or the dye layer. On the other hand, if it exceeds 0.30 g / m ² , the sensitivity of the thermal transfer recording medium itself is affected, and there is a concern that the transfer sensitivity at the time of high-speed printing is insufficient.

  The aqueous thermal transfer image-receiving sheet is obtained by laminating an aqueous hollow particle layer containing at least an aqueous binder and hollow particles and an aqueous receiving layer mainly composed of an aqueous binder and a release agent on a substrate. There is no restriction | limiting in particular about the base material used for a water-system thermal transfer image receiving sheet, According to the intended purpose etc., the thing of a various material, a layer structure, and a size can be selected and used suitably. Examples thereof include various papers such as paper, coated paper, and synthetic paper (polypropylene, polystyrene, or a composite material obtained by bonding them with paper).

(Hollow particle layer)
Furthermore, it is preferable to form a hollow particle layer containing hollow particles and an adhesive component on the image receiving paper substrate. Thermal transfer printing is performed by heating from a thermal head, and it is required that the thermal head and the image receiving paper substrate have good adhesion. Since the image receiving paper base material having the hollow particle layer has cushioning properties, the adhesiveness with the thermal head is improved, and a more uniform image can be obtained at the time of printing. As a material for forming the walls of the hollow particles, acrylonitrile, vinylidene chloride, a polymer of styrene acrylate, and the like are preferably used. Examples of the method for producing the hollow particles include a method in which a foaming agent such as butane gas is encapsulated in the resin particles and foamed by heating, an emulsion polymerization method, and the like. As a method of heating and foaming, when using pre-foamed hollow particles obtained by pre-foaming hollow particles by preheat treatment, and after forming a layer containing unfoamed particles by coating or the like, by heat treatment such as a drying step A hollow structure may be formed. From the viewpoint of easily controlling the hollow ratio and particle diameter of the hollow particles, it is generally preferable to use the already-expanded particles.

(Receptive layer)
As the dyeing resin used in the receiving layer of the present invention, a thermoplastic resin having high affinity for the dye and good dyeing property is used.

Examples of the resin include vinyl chloride resin, urethane resin, polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, polystyrene resin, polyacrylate resin, acrylic resin, cellulose resin, and polyamide resin. A thermoplastic resin such as a copolymer resin of a vinyl compound monomer and a monomer having a benzotriazole skeleton and / or a benzophenone skeleton, and these thermoplastic resins may be used alone or in combination of two or more. You may use together.
Among these, acrylic resins, copolymer resins of vinyl compound monomers and monomers having a benzotriazole skeleton and / or a benzophenone skeleton, and urethane resins are preferable because of excellent light resistance of printed images. This is because the urethane-based resin has a crystalline region in the molecule, and thus abnormal transfer hardly occurs. The dyeing resin is more preferably made of a water-soluble or water-dispersed so-called aqueous system from the viewpoint of environmental burden.

  In thermal transfer printing, the receiving layer on the image receiving paper substrate and the dye layer of the ink ribbon are overlaid and heated with a thermal head, and then the ink ribbon is peeled off from the receiving layer. And releasability is also required. For this reason, it is preferable to add a release agent to the receiving layer for the purpose of preventing fusion with the ink ribbon and improving printing runnability. Examples of the release agent to be added include silicone oil, polysiloxane graft acrylic resin, waxes, and fluorine compounds.

  It is preferable to add a crosslinking agent to the receiving layer to improve heat resistance. As a crosslinking agent, a carbodiimide compound, an isocyanate compound, an oxazoline compound, and an organic titanium chelate compound are preferable. Among these cross-linking agents, carbodiimide-based cross-linking agents are preferable because they are highly effective in improving heat resistance, are less likely to cause running problems such as ribbon fusion during printing, and are stable in aqueous paints. . The addition amount of the carbodiimide crosslinking agent is preferably 1 to 30 parts, more preferably 3 to 25 parts, with respect to 100 parts of the resin contained in the receiving layer. If it is less than 1 part, sufficient crosslinking effect cannot be obtained, and printing running failure may occur. If it exceeds 30 parts, the curing property of the resin may inhibit the density of the printed image.

The coating amount of the receptor layer is preferably from 0.5 to 5 g / ^{m 2,} more preferably 0.5-4 g / ^{m 2.} If it is less than 0.5 g / m ² , the light resistance of the image may be inferior. If it exceeds 5 g / m ² , the dye may diffuse in the receiving layer, and image bleeding may occur.

(Coating method)
Various auxiliary agents such as wetting agents, dispersants, thickeners, antifoaming agents, colorants, antistatic agents, preservatives and the like used in the production of general coated papers are appropriately added to each coating layer. . Each coating layer is a predetermined coating solution using a known coater such as a bar coater, gravure coater, comma coater, blade coater, air knife coater, gate roll coater, die coater, curtain coater, and slide bead coater. Can be formed by coating and drying each layer or two or more layers simultaneously.

The dye layer 30 may be a conventionally known one. For example, the dye layer 30 is formed by preparing a coating solution for forming a dye layer by blending a heat transfer dye, a binder, a solvent, and the like, and applying and drying. A value of about 0 g / m ² is appropriate. Note that the dye layer can be composed of a single layer of one color, or a plurality of dye layers containing dyes having different hues can be repeatedly formed on the same surface of the same base material in the surface order.

  The heat transferable dye of the dye layer 30 is not particularly limited as long as it is a dye that melts, diffuses, or sublimates and transfers by heat. For example, the yellow component may be solvent yellow 56, 16, 30. , 93, 33, Disperse Yellow 201, 231, 33, and the like. Examples of the magenta component include C.I. I. Disperse thread 60, C.I. I. Disperse violet 26, C.I. I. Solvent Red 27, or C.I. I. Solvent Red 19 etc. can be mentioned. As the cyan component, C.I. I. Disperse Blue 354, C.I. I. Solvent Blue 63, C.I. I. Solvent Blue 36, or C.I. I. Disperse Blue 24 and the like. As a black ink dye, it is common to perform color matching by combining the above dyes.

  The binder of the dye layer 30 may be any conventionally known resin binder, and is not particularly limited, but cellulose such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate and the like. Examples thereof include vinyl resins such as resin, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, and polyacrylamide, polyester resins, styrene-acrylonitrile copolymer resins, and phenoxy resins.

  Here, the ratio of the dye and the binder in the dye layer 30 is preferably dye / binder = 10/100 to 300/100. This is because when the ratio of the dye / binder is less than 10/100, the amount of the dye is too small and the color development sensitivity becomes insufficient, and a good thermal transfer image cannot be obtained, and when this ratio exceeds 300/100, This is because the solubility of the dye is extremely lowered, so that when it becomes a thermal transfer recording medium, the storage stability is deteriorated and the dye is likely to be precipitated. Further, known additives such as isocyanate compounds, silane coupling agents, dispersants, viscosity modifiers, stabilizers and the like can be used in the dye layer or the dye layer forming coating solution as long as the performance is not impaired. The heat resistant slipping layer 40, the undercoat layer 20, and the dye layer 30 can be formed by applying and drying by a conventionally known application method. An example of the application method is a gravure coating method. , Screen printing, spray coating, and reverse roll coating.

  Next, specific Examples 1 to 4 and Comparative Examples 1 to 6 according to the present invention are manufactured and compared as follows. In the following text, “part” is based on mass unless otherwise specified.

<Preparation of substrate with heat-resistant slip layer>
As a base material, a polyethylene terephthalate film with a single-sided easy adhesion treatment of 4.5 μm is used, and a heat resistant slipping layer coating solution having the following composition is applied to the non-easy adhesion treatment surface by a gravure coating method so that the coating amount after drying is 1 After coating and drying so as to be 0.0 g / m ² , the substrate with a heat-resistant slipping layer was obtained by aging in a 40 ° C. environment for 1 week.

<Heat resistant slipping layer coating solution>
Acrylic polyol resin 12.5 parts Polyoxyalkylene alkyl ether / phosphate ester 2.5 parts talc 6.0 parts 2,6-tolylene diisocyanate prepolymer 4.0 parts toluene 50.0 parts methyl ethyl ketone 20.0 parts ethyl acetate 5.0 parts (Example 1)
The undercoat layer coating solution-1 having the composition shown below is applied to the surface of the base material with a heat-resistant slip layer by a gravure coating method so that the coating amount after drying is 0.2 g / m ² and dried. As a result, an undercoat layer was formed. Subsequently, a dye layer coating solution having the following composition is applied onto the undercoat layer by a gravure coating method so that the coating amount after drying is 0.7 g / m ² , and the dye layer is formed by drying. The thermal transfer recording medium of Example 1 was obtained.

<Undercoat layer coating solution-1>
Tetraethoxysilane 2.8 parts vinylpyrrolidone-vinylcaprolactam copolymer 2.8 parts polyvinyl alcohol 2.8 parts water-dispersed polyester 2.1 parts 0.1N hydrochloric acid 53.8 parts pure water 31.8 parts isopropyl alcohol 9 parts <Dye layer coating solution>
C. I. Solvent Blue 63 6.0 parts Polyvinyl acetal resin 4.0 parts Toluene 45.0 parts Methyl ethyl ketone 45.0 parts (Example 2)
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer medium of Example 2 was obtained in the same manner as in Example 1 except that the undercoat layer was changed to the undercoat layer coating liquid-2 of the following composition. .

<Undercoat layer coating solution-2>
Stannous chloride 2.8 parts vinylpyrrolidone-vinylcaprolactam copolymer 2.8 parts polyvinyl alcohol 2.8 parts water-dispersed polyester 2.1 parts 0.1 N hydrochloric acid 53.8 parts pure water 31.8 parts isopropyl alcohol 3 .9 parts (Example 3)
In the heat-sensitive transfer recording medium produced in Example 1, the example was applied in the same manner as in Example 1 except that the undercoat layer was applied and dried so that the coating amount after drying was 0.05 g / m ^2. No. 3 thermal recording transfer medium was obtained.

Example 4
In the heat-sensitive transfer recording medium produced in Example 1, the Example was applied in the same manner as in Example 1 except that the undercoat layer was applied and dried so that the coating amount after drying was 0.35 g / m ^2. No. 4 thermal recording transfer medium was obtained.

(Comparative Example 1)
After forming the undercoat layer on the easy-adhesion treated surface of the substrate with a heat-resistant slipping layer, the same dye layer coating solution as in Example 1 is dried on the easy-adhesive treated surface by a gravure coating method. The dye layer was formed by coating and drying so that the amount of coating was 0.7 g / m ² , and the thermal transfer recording medium of Comparative Example 1 was obtained.

(Comparative Example 2)
Applying undercoat layer coating solution-3 of the following composition to the surface of easy adhesion of the base material with a heat-resistant slip layer by gravure coating so that the coating amount after drying is 0.2 g / m ² , and drying. As a result, an undercoat layer was formed. Subsequently, on the undercoat layer, the same dye layer coating solution as in Example 1 was applied and dried by the gravure coating method so that the coating amount after drying was 0.7 g / m ² . A dye layer was formed to obtain a thermal transfer recording medium of Comparative Example 2.

<Undercoat layer coating solution-3>
Polyvinyl alcohol 4.2 parts Water-dispersed polyester 4.2 parts 0.1N hydrochloric acid 53.8 parts Pure water 33.9 parts Isopropyl alcohol 3.9 parts (Comparative Example 3)
The undercoat layer coating solution-4 having the following composition is applied to the surface of the base material with a heat-resistant slip layer by a gravure coating method so that the coating amount after drying is 0.2 g / m ² and dried. As a result, an undercoat layer was formed. Subsequently, on the undercoat layer, the same dye layer coating solution as in Example 1 was applied and dried by the gravure coating method so that the coating amount after drying was 0.7 g / m ² . A dye layer was formed to obtain a thermal transfer recording medium of Comparative Example 3.

<Undercoat layer coating solution-4>
Tetraethoxysilane 4.2 parts Polyvinyl alcohol 4.2 parts 0.1 N hydrochloric acid 53.8 parts Pure water 33.9 parts Isopropyl alcohol 3.9 parts (Comparative Example 4)
The undercoat layer coating solution-5 having the following composition was applied to the surface of the base material with a heat-resistant slip layer by a gravure coating method so that the coating amount after drying was 0.2 g / m ² and dried. As a result, an undercoat layer was formed. Subsequently, on the undercoat layer, the same dye layer coating solution as in Example 1 was applied and dried by the gravure coating method so that the coating amount after drying was 0.7 g / m ² . A dye layer was formed to obtain a thermal transfer recording medium of Comparative Example 4.

<Undercoat layer coating solution-5>
Tetraethoxysilane 4.2 parts Vinylpyrrolidone-vinylcaprolactam copolymer 4.2 parts 0.1N hydrochloric acid 53.8 parts Pure water 33.9 parts Isopropyl alcohol 3.9 parts (Comparative Example 5)
The undercoat layer coating solution-6 of the following composition is applied to the surface of the base material with a heat-resistant slip layer by a gravure coating method so that the coating amount after drying is 0.2 g / m ² and dried. As a result, an undercoat layer was formed. Subsequently, on the undercoat layer, the same dye layer coating solution as in Example 1 was applied and dried by the gravure coating method so that the coating amount after drying was 0.7 g / m ² . A dye layer was formed to obtain a thermal transfer recording medium of Comparative Example 5.

<Undercoat layer coating solution-6>
Tetraethoxysilane 4.2 parts Polyvinyl alcohol 4.2 parts Water-dispersed polyester 2.1 parts 0.1N hydrochloric acid 53.8 parts Pure water 33.9 parts Isopropyl alcohol 3.9 parts (Comparative Example 6)
The undercoat layer coating solution-7 having the following composition was applied to the surface of the base material with a heat-resistant slip layer by a gravure coating method so that the coating amount after drying was 0.2 g / m ² and dried. As a result, an undercoat layer was formed. Subsequently, on the undercoat layer, the same dye layer coating solution as in Example 1 was applied and dried by the gravure coating method so that the coating amount after drying was 0.7 g / m ² . A dye layer was formed to obtain a thermal transfer recording medium of Comparative Example 6.

<Undercoat layer coating solution-7>
Tetraethoxysilane 3.5 parts Polyvinyl alcohol 3.5 parts Vinylpyrrolidone-vinylcaprolactam copolymer 3.5 parts 0.1 N hydrochloric acid 53.8 parts Pure water 33.9 parts Isopropyl alcohol 3.9 parts <Preparation of image receiving paper >
<Preparation of image receiving paper substrate>
Art paper having a thickness of 180 g / m ² was used as the image receiving paper substrate.
<Formation of hollow particle layer>
On the image receiving paper substrate, the following composition hollow particle layer coating solution is applied by a gravure coating method so that the coating amount after drying is 10 g / m ² , dried, and then in a 40 ° C. environment for one week. By aging, an image receiving paper with a hollow particle layer was obtained.

<Hollow particle layer coating solution>
Pre-expanded hollow particles made of a copolymer mainly composed of acrylonitrile and methacrylonitrile: 45 parts (average particle diameter: 3.2 μm, volume hollow ratio: 85%)
Polyvinyl alcohol 10 parts vinyl chloride vinyl acetate copolymer resin dispersion 45 parts (vinyl chloride / vinyl acetate = 70/30, Tg 64 ° C.)
Water… 200 parts <Formation of receptor layer>
By applying and drying the following composition-receiving layer coating solution on the heat insulation layer by gravure coating method so that the coating amount after drying becomes 4 g / m ^2, and then aging in a 40 ° C. environment for one week. , Got a receptive layer.

<Receptive layer coating solution>
Urethane resin: 97 parts (Glass transition temperature: -20 ° C)
Associative urethane thickener ... 1 part sulfonic acid surfactant ... 2 parts water ... 200 parts
<Evaluation of adhesion of dye layer at room temperature>
With respect to the thermal transfer recording media of Examples 1 to 4 and Comparative Examples 1 to 6, a cellophane tape having a width of 18 mm and a length of 150 mm was applied on the dye layer of the thermal transfer recording medium stored at room temperature, and immediately thereafter. Table 1 shows the results of evaluation by examining the presence or absence of the dye layer adhering to the cellophane tape when peeled off.

  Here, the evaluation was performed according to the following criteria.

○: Adhesion of the dye layer is not observed Δ: Adhesion of the dye layer is very slightly observed ×: Adhesion of the dye layer is observed on the entire surface <Evaluation of adhesion of the dye layer after storage at high temperature and high humidity >
Regarding the thermal transfer recording media of Examples 1 to 4 and Comparative Examples 1 to 6, the dye layers of the thermal transfer recording media were stored for 72 hours at 40 ° C. and 90% RH and then further stored for 24 hours at room temperature. Table 1 shows the results of evaluation by examining the presence or absence of the dye layer adhering to the cellophane tape side when a cellophane tape having a width of 18 mm and a length of 150 mm is applied to the top and then immediately peeled off. The evaluation was performed according to the same standard as the above evaluation at room temperature.
Regarding the thermal transfer recording media of Examples 1 to 4 and Comparative Examples 1 to 6, the thermal transfer recording media stored at room temperature, and after being stored in a 40 ° C. 90% RH environment for 72 hours, further 24 at normal temperature. Table 1 shows the results of evaluating the maximum reflection density, the presence / absence of abnormal transfer, and “shiny” by performing solid printing with a thermal simulator using a heat-sensitive transfer recording medium and a transfer medium that have been stored for a long time. Note that the maximum reflection density is a value obtained by measuring a printed portion where “shine” is not confirmed with X-Rite 528.

<Printing conditions>
Printing environment: 23 ° C, 50% RH
Applied voltage: 29V
Line cycle: 0.7msec
Print density: main scanning 300 dpi sub-scanning 300 dpi
<Abnormal transcription evaluation>
Also, abnormal transcription was evaluated according to the following criteria.

  The abnormal transcription was evaluated according to the following criteria.

○: Abnormal transfer to the transfer object is not observed. Δ: Abnormal transfer to the transfer object is very slight. ×: Abnormal transfer to the transfer object is observed on the entire surface.
Moreover, the evaluation of shine was performed according to the following criteria.

◯: shine is not recognized Δ: shine is partially recognized

      X: Tekari is clearly recognized.

  As can be seen from Table 1, the thermal transfer recording medium provided with the undercoat layer was clearly transferred at the time of high-speed printing as compared with the thermal transfer recording medium of Comparative Example 1 provided with no undercoat layer. It is confirmed that the sensitivity is high.

  Moreover, when water-dispersed polyester is not included from Example 1 and Comparative Example 6 and Comparative Examples 3 and 5, adhesion of the dye layer in high-temperature and high-humidity storage and abnormal transfer in printing also occur, and in high-temperature and high-humidity storage. It is confirmed that there is a problem with the adhesion of the dye layer.

  Furthermore, in Comparative Examples 2, 3, and 5 that did not contain a vinylpyrrolidone-vinylcaprolactam copolymer, “shine” was generated. Although Comparative Example 4 which contains a vinylpyrrolidone-vinylcaprolactam copolymer but does not contain a water-soluble polymer shows that “Tekari” is at a level that does not cause any practical problems, it has a problem in the maximum reflection density and abnormal transfer. Is confirmed.

  On the other hand, in Examples 1 and 2 mainly composed of at least one of alkoxide, its hydrolyzate, and tin chloride, vinylpyrrolidone-vinylcaprolactam copolymer, polyvinyl alcohol, and water-dispersible polyester, It is confirmed that there is no practical problem with the adhesion of the dye layer in storage and high temperature / high humidity storage, abnormal transfer in printing, and “shine” occurring in high density areas.

In addition, although the thermal transfer recording medium of Example 3 has good transfer sensitivity, the coating amount of the undercoat layer is less than 0.10 g / m ² , so the adhesion after storage at a somewhat high temperature and high humidity is somewhat. Further, it is confirmed that the effect of the transfer sensitivity is lowered in the thermal transfer recording medium of Example 4 because the coating amount of the undercoat layer is more than 0.30 g / m ² .

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, the problems described in the column of problems to be solved by the invention can be solved, and the effects described in the effects of the invention can be obtained. In some cases, a configuration from which this configuration requirement is deleted can be extracted as an invention.

  The thermal transfer recording medium obtained according to the present invention is an ink ribbon used in a sublimation transfer type printer, and in addition to the high speed and high functionality of the printer, various images can be easily formed in full color. Can be used widely, such as self-prints, cards such as identification cards, and amusement output.

DESCRIPTION OF SYMBOLS 10 ... Base material 20 ... Undercoat layer 30 ... Dye layer 40 ... Heat-resistant slipping layer

Claims (5)

For forming an image by thermal transfer on a thermal transfer image-receiving sheet in which an aqueous receiving layer containing an aqueous binder and a release agent is formed on a substrate via an aqueous hollow particle layer containing an aqueous binder and hollow particles A thermal transfer recording medium,
A heat resistant slipping layer is provided on one surface of the substrate, and an undercoat layer and a dye layer are sequentially formed on the other surface of the substrate. The undercoat layer comprises an alkoxide, a hydrolyzate thereof, and tin chloride. A thermal transfer recording medium comprising at least one of the following: vinylpyrrolidone-vinylcaprolactam copolymer, water-soluble polymer, and water-dispersible polyester as main components.   The heat-sensitive transfer recording medium according to claim 1, wherein the water-soluble polymer is polyvinyl alcohol.   3. The water-dispersible polyester is characterized in that at least an ester-forming sulfonic acid alkali metal salt compound is copolymerized as a dicarboxylic acid component, and diethylene glycol is copolymerized as a diglycol component. Thermal transfer recording medium.   The thermal transfer recording medium according to any one of claims 1 to 3, wherein the alkoxide is tetraethoxysilane, triisopropoxyaluminum, or a mixture thereof. 5. The feeling according to claim 1, wherein the coating amount of the undercoat layer after drying is in the range of 0.10 g / m ² or more and 0.30 g / m ² or less. Thermal transfer recording medium.

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