JP5686008B2 - Thermal transfer recording medium - Google Patents

Description

  The present invention relates to a thermal transfer recording medium used in a thermal transfer printer, and in particular, a heat-resistant slipping layer is provided on one surface of a substrate, and an undercoat layer and a dye layer are provided on the other surface of the substrate. The present invention relates to sequentially formed thermal transfer recording media. 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 image receiving layer of the transfer object is fused to the heat-sensitive transfer recording medium, causing hue fluctuations, and as a result, the surface of the print is partially matted. 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. Here, the heat-sensitive transfer layer is an ink layer, and the ink is sublimated (sublimation transfer method) or melted (melt transfer method) by 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. Along with the diversification of applications, there is a growing demand for miniaturization, high speed, low cost, and durability for the prints that can be obtained. 2. Description of the Related Art Thermal transfer recording media having a plurality of thermal transfer layers provided so as not to overlap with a protective layer to be applied have become quite popular.

  Under such circumstances, along with the diversification and widespread use of applications, there has been a problem that sufficient print density cannot be obtained with the conventional thermal transfer recording medium as the printing speed of the printer further increases. 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. However, wrinkles due to heat, pressure, etc. may occur during the manufacture of the thermal transfer recording medium or during printing. Occurs, or in some cases breaks.

  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.

  Attempts have also 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 increases, but also the life of the thermal head of the printer is shortened. And the material to be transferred 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.

  In order to solve such a problem, 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.

  Patent Document 3 proposes a thermal transfer sheet having a base layer composed of a copolymer of vinylpyrrolidone and vinyl acetate and colloidal inorganic pigment ultrafine particles between a base material and a dye layer.

JP-A-2005-231354 JP 2006-150956 A JP 2008-155612 A

  However, in the thermal transfer recording medium proposed in Patent Document 1, when printing is performed with a sublimation transfer type high-speed printer, abnormal transfer is not confirmed, including those stored under high temperature and high humidity. The transfer sensitivity in printing was low, it did not reach a sufficient level, and “shine” could not be suppressed sufficiently. In addition, in the thermal transfer recording medium proposed in Patent Document 2, when printing is performed, the transfer sensitivity in printing is high and has reached a sufficient level, but it is stored at high temperature and high humidity and abnormal transfer is performed. In addition, “shine” could not be suppressed sufficiently. In addition, in the thermal transfer recording medium proposed in Patent Document 3, when printing is performed, the transfer sensitivity in printing is high and has reached a sufficient level, including those stored at high temperature and high humidity, Although there was no problem with abnormal transfer, printing unevenness was confirmed, and “shine” could not be sufficiently suppressed. In this way, all of the conventional technologies have high transfer sensitivity in printing, and even when stored under high temperature and high humidity, abnormal transfer does not occur, and thermal transfer recording that can be applied to high-speed printers that have sufficiently improved the phenomenon of shine. The situation is that no medium has been found.

  Therefore, 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 also after storage under high temperature and high humidity. In addition, abnormal transfer in printing can be prevented, and image quality defects occurring in high density areas, that is, hue fluctuation occurs due to the image receiving layer of the transfer target being fused to the thermal transfer recording medium, resulting in the surface of the print being It is an object of the present invention to provide a heat-sensitive transfer recording medium that can reduce the phenomenon of so-called “shininess” that is partially matted.

The invention according to claim 1 is a thermal transfer recording medium in which 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. Are a silicon compound represented by the general formula Si (OR ¹ ) ₄ and / or a hydrolyzate thereof, and a silicon compound represented by the general formula (R ² Si (OR ³ ) ₃ ) _n and / or a hydrolysis thereof. (Wherein R ¹ and R ³ are CH ₃ , C ₂ H ₅ , or C ₂ H ₄ OCH ₃ , R ² represents an organic functional group), vinylpyrrolidone-vinylimidazole copolymer, water dispersible polyester, It is formed by applying and drying a coating liquid containing a water-soluble polymer as a main component , and the general formula (R ² Si (OR ³ ) ₃ ) _n is represented by the formula (NCO-R ⁴ Si (OR ³ ) ₃ ). ₃ (wherein R ⁴ is (CH ₂ ) _n , n is 1 ) A thermal transfer recording medium characterized in that it is a trimer 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate represented by the above .

The invention according to claim 2 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 diethylene glycol as a diglycol component. a thermal transfer recording medium according to claim 1 Symbol mounting and.

The invention of claim 3, wherein, the water-soluble polymer, a thermal transfer recording medium according to claim 1 or 2, wherein the polyvinyl alcohol.

The invention of claim 4, wherein the silicon compound represented by the general formula Si (OR ¹⁾ ₄ is sensitive to any one of claims 1 to 3, characterized in that tetraethoxysilane It is a thermal transfer recording medium.

Further, an invention according to claim 5, the coating amount after drying of the undercoat layer is, any one of claims 1 to 4, characterized in that in the range of 0.10~0.30g / ^{m 2} A thermal transfer recording medium according to item 1.

  According to the heat-sensitive transfer recording medium of the present invention, the transfer sensitivity at the time of high-speed printing is high, that is, high-density printing can be obtained without increasing the dye used in the dye layer, and even after storage at high temperature and high humidity. There is no abnormal transfer in printing, and a sufficiently satisfactory printed material with less so-called “shine” phenomenon can be obtained.

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

  Hereinafter, a thermal transfer recording medium according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a heat-sensitive transfer recording medium according to an embodiment of the present invention, and a heat-resistant slipping layer 2 that imparts slidability with a thermal head is provided on one surface of a substrate 1. An undercoat layer 3 and a dye layer 4 are sequentially formed on the other surface of the substrate 1.

  Since the base material 1 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.

  Moreover, in the said base material 1, it is also possible to give an adhesion | attachment process to the surface in which the heat resistant slipping layer 2 and / or the undercoat layer 3 are 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.

The heat-resistant slip layer 2 can be handled by a conventionally known one, and is prepared by blending, for example, a resin serving as a binder, a functional additive imparting releasability and slipperiness, a filler, a curing agent, a solvent, and the like. It 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 slipping layer 2, as the binder resin, 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 3 includes, as essential components of the present invention, a silicon compound represented by the general formula Si (OR ¹ ) ₄ and a hydrolyzate thereof, and a general formula (R ² Si (OR ³ ) ₃ ) _n. And a hydrolyzate thereof (wherein R ¹ and R ³ are CH ₃ , C ₂ H ₅ , or C ₂ H ₄ OCH ₃ , R ² represents an organic functional group) and vinylpyrrolidone- A coating solution containing a vinylimidazole copolymer, a water-dispersible polyester, and a water-soluble polymer as main components can be applied and dried.

  Examples of water-soluble polymers 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 vinyl pyrrolidone-vinyl imidazole copolymer is a copolymer of an N-vinyl pyrrolidone monomer and a vinyl imidazole 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.

Here, the metal alkoxide represented by the general formula Si (OR ¹ ) ₄ is condensed after hydrolysis to form a polymer having a chain or three-dimensional structure. However, since the metal oxide is hard and cracks easily occur due to distortion due to volume reduction during condensation, it is very difficult to form a thin, transparent and uniform condensate film on the film. Therefore, by adding a polymer, flexibility can be imparted to the structure, and cracking can be prevented to form a film. The metal alkoxide forms a complex at the molecular level with a water-soluble polymer, and the alkoxide or / and its hydrolyzate in the undercoat layer contributes to the improvement of transfer sensitivity at the time of high-speed printing where the water-soluble polymer alone is insufficient. I think that. However, the subbing layer consisting of a mixture of a metal alkoxide or its hydrolyzate and a water-soluble polymer having a hydroxyl group is composed of hydrogen bonds, so that the subbing layer swells with water during long-term storage under high temperature and high humidity. The deterioration of the adhesive tends to cause a decrease in adhesion.

In contrast, in the present invention, by adding the above-mentioned general formula _{^{(R 2 Si (OR 3)}} 3) a compound represented by _n, it is possible to prevent this swelling. In the general formula (R ² Si (OR ³ ) ₃ ) _n , the organic functional group (R ₂ ) is preferably a non-aqueous functional group such as vinyl, epoxy, methacryloxy, ureido, and isocyanate. The water resistance of the non-aqueous functional group is further improved because the functional group is hydrophobic. General Formula (R ² Si (OR ³ ) ₃ ) When the compound represented by _n is a multimer, a trimer is preferable, and more preferably, the general formula (NCO-R ⁴ Si (OR ³ ) ₃ ) ₃ (wherein R ⁴ is (CH ₂ ) _n , n is 1 or more), 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate. This is a condensate of 3-isocyanatoalkylalkoxysilane. This 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate is known to exhibit the same performance as the reaction due to the polarity of the nurate part, although the isocyanurate part has no chemical reactivity. Yes.

In general, it is added to an adhesive or the like in the same manner as 3-isocyanate alkylalkoxysilane and is known as an adhesion improver. Therefore, by adding 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate to Si (OR ¹ ) ₄ and a water-soluble polymer having a hydroxyl group, it is prevented from swelling due to water and is resistant to moisture. Can be improved.

  1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate may be produced by thermal condensation of 3-isocyanatepropylalkoxysilane, and may contain 3-isocyanatepropylalkoxysilane as a raw material. But there is no problem.

In the general formula Si (OR ¹ ) ₄ , R ¹ may be represented by CH ₃ , C ₂ H ₅ , C ₂ H ₄ OCH _3, etc., but tetraethoxysilane Si (OC ₂ H ₅ ) ₄ is particularly preferable. It is preferable because it is relatively stable in an aqueous solvent after hydrolysis.

  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, and includes 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 such as succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid Examples thereof include dicarboxylic 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 the hydrophobic plastic, the adhesion is improved. There is an advantage of excellent hydrolyzability. 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 alkali metal salt of sulfonic acid 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 ester-forming sulfonic acid alkali metal salt compounds include sulfoterephthalic acid, 5-
Examples include alkali metal salts (alkali metal salts of sulfonic acid) such as sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and ester-forming derivatives thereof. A sodium salt of isophthalic acid and an ester-forming derivative thereof 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, solvent resistance to alcohol can be obtained, but solvent resistance to aromatic solvents such as toluene and xylene is insufficient.

  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.

The coating amount after drying of the undercoat layer 3 is not generally limited, but is preferably in the range of 0.10 to 0.30 g / m ² . If it is less than 0.10 g / m ² , there is a concern that the transfer sensitivity at the time of high-speed printing may be insufficient due to deterioration during lamination of the dye layer, or that there is a problem in 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 fear that the transfer sensitivity at the time of high-speed printing is insufficient.

In addition, the dye layer 4 can be supported by a conventionally known one, for example, a dye layer forming coating solution is prepared by blending a heat transferable dye, a binder, a solvent, and the like, formed by coating and drying, About 1.0 g / m ² is appropriate. In addition, the dye layer 4 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 4 is not particularly limited as long as it is a dye that melts, diffuses, or sublimates and transfers due to heat. For example, the yellow component includes 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.

  As the binder of the dye layer 4, any conventionally known resin binder can be used, and is not particularly limited. However, cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, and cellulose acetate are used. And vinyl resins such as 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 4 is preferably dye / binder = 10/100 to 300/100. This is because if the dye / binder ratio is less than 10/100, the amount of dye is too small and the color development sensitivity is insufficient, and a good thermal transfer image cannot be obtained. This is because the solubility of the dye with respect to the ink 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.

  Next, the image receiving paper used as the transfer material used in the present invention will be described.

  As the image receiving paper substrate, papers mainly composed of cellulose pulp can be used. Examples of paper include coated paper, art paper, high-quality paper (acidic paper, neutral paper), medium-quality paper, and glassine paper.

  Furthermore, it is preferable to form a heat insulating 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 heat insulating layer has cushioning properties, adhesion 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 used in the heat insulating layer, 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 in which hollow particles are pre-foamed by overheating, and after forming a heat insulating layer containing unfoamed particles by coating, etc., heat treatment such as a drying step May form a hollow structure in the heat insulating layer. 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.

  As the dyeing resin used for the image-receiving paper substrate or the image-receiving layer formed on the heat insulating layer, a thermoplastic resin having high affinity for dyes and good dye-dying 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. Further, the dyeing resin is more preferably composed of a water-soluble or water-dispersed so-called aqueous system from the viewpoint of environmental load.

In thermal transfer printing, the image receiving layer on the image receiving paper substrate and the dye layer of the ink ribbon are superposed and heated with a thermal head, and then the ink ribbon is peeled off from the image receiving layer. And releasability is also required. For this reason, it is preferable to add a release agent to the image 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.
The image-receiving layer is preferably improved in heat resistance by adding a crosslinking agent. 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 image 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 image-receiving 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 image receiving layer, and image bleeding may occur.

  Hereinafter, specific Examples 1 to 6 and Comparative Examples 1 to 6 according to the present invention will be manufactured and compared. In the text, “part” is based on mass unless otherwise specified.

<Preparation of substrate with heat-resistant slip layer>
As a base material 1, a polyethylene terephthalate film with a single-sided easy-adhesion treatment of 4.5 μm is used. After apply | coating and drying so that it might become 1.0 g / m < ² >, the base material with a heat-resistant slipping layer was obtained by aging for one week in a 40 degreeC environment.

<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 <Preparation of undercoat layer coating solution>
A: 17.3 parts of tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) and 10.0 parts of methanol were added 72.7 parts of hydrochloric acid (0.1N), and the mixture was stirred for 30 minutes for hydrolysis. solution
B: Dissolution of 1.5 parts of polyvinyl alcohol, 2.5 parts of vinylpyrrolidone-vinylimidazole copolymer and 1.0 part of water dispersible polyester in a mixed solution of 90.0 parts of water and 5.0 parts of methanol. Liquid C: 2.5 parts of polyvinyl alcohol, 1.5 parts of vinylpyrrolidone-vinylimidazole copolymer and 1.0 part of water dispersible polyester were dissolved in a mixed liquid of 90.0 parts of water and 5.0 parts of methanol. Solution D: 1.5 parts of polyvinyl alcohol, 1.5 parts of vinylpyrrolidone-vinylimidazole copolymer and 2.0 parts of water-dispersible polyester are dissolved in a mixture of 90.0 parts of water and 5.0 parts of methanol. Solution E: 1.5 parts of polyvinylpyrrolidone, 2.5 parts of vinylpyrrolidone-vinylimidazole copolymer and water dispersibility in a mixture of 90.0 parts of water and 5.0 parts of methanol Solution F in which 1.0 part of reester is dissolved: Solution G in which 2.5 parts of polyvinyl alcohol and 2.5 parts of water-dispersible polyester are dissolved in a mixture of 90.0 parts of water and 5.0 parts of methanol : Dissolved solution obtained by dissolving 2.5 parts of polyvinyl alcohol and 2.5 parts of vinylpyrrolidone-vinylimidazole copolymer in a mixed solution of 90.0 parts of water and 5.0 parts of methanol H: 90.0 parts of water and methanol Dissolved solution obtained by dissolving 2.5 parts of vinylpyrrolidone-vinylimidazole copolymer and 2.5 parts of water-dispersible polyester in 5.0 parts of a mixed solution I: 45.0 parts of water, 45.0 parts of IPA, 1, Mixture obtained by mixing 10.0 parts of 3,5-tris (3-methoxysilylpropyl) isocyanurate and stirring for 5 minutes <Preparation of image-receiving paper to be transferred>
<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 heat insulation layer>
On the image receiving paper substrate, the following composition heat insulating layer coating solution is applied by gravure coating so that the coating amount after drying is 10 g / m ² , dried, and then aged in a 40 ° C. environment for one week. Thus, an image receiving paper with a heat insulating layer was obtained.

<Insulation layer coating solution>
45 parts of pre-expanded hollow particles made of a copolymer mainly composed of acrylonitrile and methacrylonitrile (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, T _g 64 ° C.)
200 parts of water <formation of image receiving layer>
By applying and drying the following composition image-receiving layer coating solution on the heat insulation layer by a 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. An image receiving layer was obtained.

<Image-receiving layer coating solution>
97 parts of urethane resin (glass transition temperature: -20 ° C)
Associative urethane thickener 1 part Sulfonic acid surfactant 2 parts Water 200 parts (Example 1)
The undercoat layer coating solution prepared above is mixed at A / B / I = 70/20/10 on the easy-adhesion treated surface of the substrate 1 with a heat-resistant slipping layer and stirred for 30 minutes. Thus, the undercoat layer 3 was formed by coating and drying so that the coating amount after drying was 0.2 g / m ² . Subsequently, a dye layer coating solution having the following composition is applied and dried on the undercoat layer 3 by a gravure coating method so that the coating amount after drying is 0.7 g / m ^2. 4 was obtained, and the thermal transfer recording medium of Example 1 was obtained.

<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 heat-sensitive transfer recording medium produced in Example 1, the same procedure as in Example 1 was conducted, except that the undercoat layer coating solution prepared above for the undercoat layer 3 was mixed at A / C / I = 70/20/10. Thus, a thermal recording transfer medium of Example 2 was obtained.

Example 3
In the heat-sensitive transfer recording medium produced in Example 1, the same procedure as in Example 1 was conducted except that the undercoat layer coating solution prepared as described above was mixed at A / D / I = 70/20/10. Thus, a thermal recording transfer medium of Example 3 was obtained.

Example 4
In the heat-sensitive transfer recording medium produced in Example 1, the same procedure as in Example 1 was conducted except that the undercoat layer coating liquid prepared as described above was mixed at A / E / I = 70/20/10. Thus, a thermal recording transfer medium of Example 4 was obtained.

(Example 5)
In the heat-sensitive transfer recording medium produced in Example 1, the same procedure as in Example 1 was carried out except that the undercoat layer 3 was applied and dried so that the coating amount after drying was 0.05 g / m ^2. The thermal recording transfer medium of Example 5 was obtained.

(Example 6)
In the heat-sensitive transfer recording medium produced in Example 1, the same procedure as in Example 1 was carried out except that the undercoat layer 3 was applied and dried so that the coating amount after drying was 0.35 g / m ^2. The heat-sensitive recording transfer medium of Example 6 was obtained.

(Comparative Example 1)
Without forming the undercoat layer 3 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-adhesion treated surface by a gravure coating method. The dye layer was formed by coating and drying so that the subsequent coating amount was 0.7 g / m ² , and the thermal transfer recording medium of Comparative Example 1 was obtained.

(Comparative Example 2)
In the heat-sensitive transfer recording medium produced in Example 1, the same procedure as in Example 1 was conducted except that the undercoat layer coating solution prepared as described above for the undercoat layer 3 was mixed at A / F / I = 70/20/10. Thus, a thermal recording transfer medium of Comparative Example 2 was obtained.

(Comparative Example 3)
In the heat-sensitive transfer recording medium produced in Example 1, the same procedure as in Example 1 was conducted except that the undercoat layer coating solution prepared as described above for the undercoat layer 3 was mixed at A / G / I = 70/20/10. Thus, a thermal recording transfer medium of Comparative Example 3 was obtained.

(Comparative Example 4)
In the heat-sensitive transfer recording medium produced in Example 1, the same procedure as in Example 1 was conducted except that the undercoat layer coating solution prepared as described above was mixed at A / H / I = 70/20/10. Thus, a thermal recording transfer medium of Comparative Example 4 was obtained.

(Comparative Example 5)
In the heat-sensitive transfer recording medium produced in Example 1, a comparative example was prepared in the same manner as in Example 1 except that the undercoat layer coating liquid prepared as described above was mixed at A / B = 70/30. No. 5 thermal recording transfer medium was obtained.

(Comparative Example 6)
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer medium of Comparative Example 6 was prepared in the same manner as in Example 1 except that the undercoat layer coating liquid prepared as described above for the undercoat layer 3 was only B. Got.

<Evaluation of adhesion of dye layer at room temperature>
Regarding the thermal transfer recording media of Examples 1 to 6 and Comparative Examples 1 to 6, a cellophane tape having a width of 24 mm and a length of 150 mm was pasted on the dye layer 4 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 adhesion of the dye layer 4 to the cellophane tape when peeled off.

  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 recognized on the entire surface <Dye layer adhesion evaluation after storage at high temperature and high humidity >
The thermal transfer recording media of Examples 1 to 6 and Comparative Examples 1 to 6 were stored for 72 hours, 84 hours, and 96 hours in an environment of 50 ° C. and 80% RH, respectively, and then stored for 24 hours at room temperature. When a cellophane tape having a width of 24 mm and a length of 150 mm is pasted on the dye layer of the thermal transfer recording medium and then immediately peeled off, the result of evaluation by examining the presence or absence of the dye layer on the cellophane tape side is evaluated. Table 1 shows. The evaluation was performed according to the same standard as the above evaluation at normal temperature.

<Print evaluation>
Regarding the thermal transfer recording media of Examples 1 to 6 and Comparative Examples 1 to 6, the thermal transfer recording media stored at room temperature and stored at 50 ° C. and 80% RH for 72 hours, 84 hours, and 96 hours, respectively. After that, using a thermal transfer recording medium and a transfer medium stored for 24 hours at room temperature, solid printing was performed under the following conditions with a thermal simulator to evaluate the maximum reflection density, presence of abnormal transfer, and shine. The results are shown in Table 2. Note that the maximum reflection density is a value obtained by measuring a print portion where no shine is 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
Also, 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. The following criteria were used.

○: shine is not recognized △: shine is partially recognized ×: shine is clearly recognized

That is, the thermal transfer recording media of Examples 1 to 6 are clearly more sensitive to high speed printing than the thermal transfer recording media of Comparative Example 1 in which the undercoat layer 3 is not provided, as shown in Tables 1 and 2. It was found that the transfer sensitivity was high. It was also found that there is no practical problem with the adhesion of the dye layer during normal temperature storage and high temperature / high humidity storage, abnormal transfer in printing, and “shine” occurring in high density areas. Further, in the thermal transfer recording medium of Example 5, the adhesion after the storage at a high temperature and high humidity is somewhat lowered because the coating amount of the undercoat layer 3 is less than 0.10 g / m ^2. Recognize. In addition, it can be understood that the effect of the transfer sensitivity is lowered in the thermal transfer recording medium of Example 6 because the coating amount of the undercoat layer 3 exceeds 0.30 g / m ² .

  In contrast, in the thermal transfer recording medium of Comparative Example 2, as compared with the thermal transfer recording medium of Example 1, as a result of removing the vinylpyrrolidone-vinylimidazole copolymer from the undercoat layer 3, the transfer sensitivity and abnormalities were reduced. Although sufficient performance is obtained for transfer, it can be seen that there is a problem with shine. Further, the heat-sensitive transfer recording medium of Comparative Example 3 lacks water-dispersible polyester as the undercoat layer 3, resulting in insufficient adhesion between the dye layer 4 and the undercoat layer 3 at high temperature and high humidity, and abnormal transfer occurs. You can see that Such insufficient adhesion at high temperature and high humidity is caused by Comparative Example 5 lacking 1,3,5-tris (3-methoxysilylpropyl) isocyanurate, tetraethoxysilane and 1,3,5-tris (3-methoxy). The same is true for Comparative Example 6 which lacks (silylpropyl) isocyanurate. On the other hand, the thermal transfer recording medium of Comparative Example 4 is practical even in high-temperature and high-humidity storage as a result of lacking polyvinyl alcohol, which is a water-soluble polymer, from the undercoat layer 3 as compared with the thermal transfer recording medium of Example 1. It can be seen that although the adhesion and shine can be ensured, the effect of transfer sensitivity can hardly be confirmed.

  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 1 ... Base material 2 ... Heat-resistant slip layer 3 ... Undercoat layer 4 ... Dye layer

Claims (5)

In a heat-sensitive transfer recording medium in which 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,
The undercoat layer includes a silicon compound represented by the general formula Si (OR ¹ ) ₄ or / and a hydrolyzate thereof, and a silicon compound represented by the general formula (R ² Si (OR ³ ) ₃ ) _n or / Oyo patron hydrolysates ^{(wherein, R 1,} R ³ is _{CH 3,} C 2 _{H 5} or ^{_{C 2 H 4 OCH 3, R}} 2, represents an organic functional group) and vinylpyrrolidone - vinylimidazole copolymer It is formed by applying a coating liquid containing water-dispersible polyester and water-soluble polymer as main components and drying ,
The general formula (R ² Si (OR ³ ) ₃ ) _n is a formula (NCO-R ⁴ Si (OR ³ ) ₃ ) ₃ (wherein R ⁴ is (CH ₂ ) _n , n is 1 or more). A heat- sensitive transfer recording medium characterized by being represented by a trimer 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate . The water-dispersible polyester is at least an ester-forming sulfonic acid alkali metal salt compound as the dicarboxylic acid component is copolymerized, the heat-sensitive transfer of that claim 1 Symbol mounting, characterized in that diethylene glycol as diglycol component are copolymerized recoding media. The water-soluble polymer, a thermal transfer recording medium according to claim 1 or 2, wherein the polyvinyl alcohol. Formula Si (OR ¹⁾ a silicon compound represented by the ₄ heat-sensitive transfer recording medium of any one of claims 1 to 3, wherein the tetraethoxysilane. Coating amount after drying of the undercoat layer is a thermal transfer recording medium of any one of claims 1 to 4, characterized in that in the range of 0.10~0.30g / m ^2.

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