JP2012196913A - Thermal transfer recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer recording medium exhibiting excellent slipping properties in all printing energies to be applied to a heat-resistant slipping layer, and having a small friction difference between in low-energy printing and high-energy printing to reduce printing creases.SOLUTION: The thermal transfer recording medium includes: at least a base material 46; an undercoat layer 44 and a dye layer 42 provided on one surface of the base material 46; and the heat-resistant slipping layer 48 provided on the other surface of the base material 46. The undercoat layer 44 contains at least a water-soluble polymer and a vinylpyrrolidone vinyl caprolactam copolymer. The heat-resistant slipping layer 48 contains at least two kinds of lubricants with different melting points, and a coefficient of static friction in an environment at 25-100°C is set to 0.4 or less.

Description

  The present invention relates to a thermal transfer recording medium used in a thermal transfer type printer, and in particular, prevents the occurrence of printing wrinkles even at high-speed printing, has low printing density unevenness, and is heat resistant enough to cope with high energy printing. The present invention relates to a heat-sensitive transfer recording medium having a heat-resistant slipping layer having properties.

  2. Description of the Related Art Conventionally, characters and images are formed on a transfer target using a thermal transfer system. The thermal transfer recording medium here is generally called a thermal ribbon and is an ink ribbon used in the thermal transfer system. As the thermal transfer system, a sublimation transfer system and a melt transfer system are widely used. In each of these methods, the ink of the dye layer is sublimated or melted by the heat of the thermal head and transferred to a transfer medium to form an image.

  Currently, thermal transfer systems are used in a wide variety of ways, including the enhancement of printer functionality, the output of identification photos and facial photos to cards, and the composite photos at amusement facilities. Along with such diversification of applications, the speed of printers has been increasing in recent years, and as a result, the thermal energy applied to the thermal head increases and the temperature of the thermal head itself also increases. Therefore, the influence on the heat-sensitive transfer recording medium is increased, and heat resistance higher than that in the past is required.

  This thermal transfer recording medium is provided with a dye layer on one side of a base material, for example, a polyethylene terephthalate film (PET), and a heat-resistant slipping layer in contact with the thermal head of the printer on the other side. This heat-resistant slipping layer has been conventionally provided for imparting self-cleaning properties, improving the durability of the thermal head, reducing heat conduction unevenness from the thermal head, adjusting running performance, and the like.

  However, if the slipperiness of the heat resistant slipping layer is insufficient, the substrate and the thermal head will stick together, resulting in poor printing (sticking), and slipperiness during low energy printing and high energy printing. If there is a large difference between the two, the friction coefficient is greatly different, and there is a problem of causing printing wrinkles.

  Also, when heat is applied from the thermal head to the heat-resistant slipping layer, the unevenness of the thermal transfer recording medium and the thermal transfer image-receiving sheet affects the heat transfer from the thermal head, resulting in uneven printing. There is a problem that printing defects such as density unevenness occur.

  Therefore, recently, a technique for preventing the occurrence of printing wrinkles by improving the lubricity at the time of high-energy printing by adding metal soap and filler together with the silicone-modified resin to the heat-resistant slipping layer has been proposed (for example, Patent Document 1).

JP 2006-306017 A

  However, with the technique described in Patent Document 1, the slipperiness at the time of high-energy printing is improved, and good slipperiness cannot be obtained in printing at any energy. Therefore, there is a problem that it is difficult to sufficiently prevent printing wrinkles due to a large difference in friction between the thermal head and the heat-resistant slipping layer between low energy printing and high energy printing.

  On the other hand, the inventor provided a heat-resistant slipping layer on one surface of the base material, and provided the undercoat layer and the dye layer on the other surface of the base material in this order. , By containing at least a water-soluble polymer and a vinylpyrrolidone-vinylcaprolactam copolymer, the transfer sensitivity at the time of high-speed printing is high, that is, the dye used in the dye layer can be reduced, resulting in poor image quality occurring at high density portions That is, the present inventors have discovered a technique capable of reducing the shine phenomenon, in which hue fluctuation occurs when the image receiving layer of the transfer target is fused to the thermal transfer recording medium, resulting in partial matting of the surface of the printed material.

  However, the transfer sensitivity at the time of high-speed printing by this technique becomes high, and the fact that the dye used in the dye layer can be reduced leads to a reduction in the thickness of the dye layer, that is, the heat resistance of the thermal transfer recording medium. Therefore, when a subbing layer containing a water-soluble polymer and a vinylpyrrolidone-vinylcaprolactam copolymer is provided between the substrate and the dye layer, the heat resistant slipping layer is required to have further improved heat resistance.

  The present invention has been made in view of the above circumstances, has a stable slipperiness and heat resistance, and at any temperature and printing energy, the friction with the thermal head does not change abruptly. It is an object of the present invention to provide a heat-sensitive transfer recording medium capable of giving a printed product having no print density unevenness.

  The invention according to claim 1 of the present invention provides 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 provided in this order on the other surface of the substrate. The undercoat layer includes at least a water-soluble polymer and a vinylpyrrolidone-vinylcaprolactam copolymer, and the heat resistant slipping layer includes at least two kinds of lubricants having melting points of 5 ° C. or more, and includes 25 ° C. The static friction coefficient is 0.4 or less in an environment of ˜100 ° C.

  According to a second aspect of the present invention, in the thermal transfer recording medium according to the first aspect, the heat-resistant slipping layer has an absolute value of a difference between a static friction coefficient at 25 ° C. and a static friction coefficient at 100 ° C. of 0.04. It is characterized by the following.

  The invention according to claim 3 of the present invention is the thermal transfer recording medium according to claim 1 or 2, wherein the total amount of the lubricant contained in the heat-resistant slipping layer is in the heat-resistant slipping layer. It is characterized by being 5 to 25% by mass.

  According to a fourth aspect of the present invention, in the thermal transfer recording medium according to any one of the first to third aspects, at least one of the lubricants included in the heat-resistant slipping layer is at least one type. The melting point is 50 to 100 ° C.

  According to a fifth aspect of the present invention, in the heat-sensitive transfer recording medium according to any one of the first to fourth aspects, the melting point of the lubricant contained in the heat-resistant slipping layer is 30 ° C. It is characterized by the above differences.

  The invention according to claim 6 of the present invention is the thermal transfer recording medium according to any one of claims 1 to 5, wherein the water-soluble polymer contained in the undercoat layer is polyvinyl alcohol. Features.

  According to the heat-sensitive transfer recording medium of the present invention, a heat-resistant slipping layer is provided on one surface of the base material, and an undercoat layer and a dye layer are provided in this order on the other surface of the base material. Includes at least a water-soluble polymer and a vinylpyrrolidone-vinylcaprolactam copolymer, and includes at least two kinds of lubricants having a melting point of 5 ° C. or higher, and the heat-resistant slipping layer has a melting point of 25 ° C. to 100 ° C. By setting the coefficient of static friction to 0.4 or less in the environment, it has stable lubricity and heat resistance at any temperature and printing energy, and prevents printing defects such as printing wrinkles due to low friction with the thermal head. The durability of the thermal head can be improved.

  The heat-resistant slipping layer has an absolute value of the difference between the static friction coefficient at 25 ° C. and the static friction coefficient at 100 ° C. of 0.04 or less, so that the friction during low energy printing and high energy printing is The difference is small and printing defects such as printing wrinkles can be prevented.

1 is a side sectional view showing a configuration of 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 thermal transfer recording medium 50 according to an embodiment of the present invention. An undercoat layer 44 and a dye layer 42 are sequentially laminated on one surface of a substrate 46. A heat-resistant slip layer 48 is provided on the other surface of the substrate 46.

  As the base material 46, a material equivalent to that used as a base material of a conventionally known thermal transfer recording medium can be used, and preferably has mechanical strength, heat resistance and the like. For example, polyethylene terephthalate, polyethylene naphthalate, polystyrene, polypropylene, polycarbonate, polyvinyl chloride, polyvinyl alcohol, polysulfone, aliphatic polyamide, aromatic polyamide, polyimide, polyamideimide, and other synthetic resin films, condenser paper, paraffin paper, etc. Papers. In particular, a polyethylene terephthalate film that is excellent in terms of physical properties and processability is preferable. The thickness of the base material can be 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, it is about 2 to 10 μm. Is preferred.

  The heat-resistant slip layer 48 is provided to prevent thermal contraction of the substrate due to the heat of the thermal head and breakage of the substrate due to friction with the thermal head. Examples of the binder used in the heat resistant slipping layer include cellulose resins, polyester resins, acrylic resins, vinyl resins, polyurethane resins, polyether resins, polycarbonate resins, and acetal resins.

  Next, the lubricant that is a feature of the present invention will be described.

  Examples of the at least two kinds of lubricants contained in the heat resistant slipping layer 48 include natural waxes such as animal waxes and plant waxes, synthetic hydrocarbon waxes, aliphatic alcohols and acid waxes, and fatty acid esters. Glycerite wax, synthetic ketone wax, amine and amide wax, chlorinated hydrocarbon wax, synthetic wax such as alpha-olefin wax, higher fatty acid ester such as butyl stearate and ethyl oleate, sodium stearate, stearic acid Higher fatty acid metal salts such as zinc, calcium stearate, potassium stearate, magnesium stearate, long chain alkyl phosphates, polyoxyalkylene alkylaryl ether phosphates, or polyoxyalkylene alkyl ethers And surfactants such as phosphoric acid esters such as acid esters.

  At least two or more kinds of lubricants contained in the heat-resistant slip layer 48 must have melting points different by 5 ° C. or more. The lubricant dissolves when heat is applied from the thermal head, improves the lubricity, and reduces the load on the heat-sensitive transfer recording medium due to heat. At that time, if there is no stable slipperiness at any temperature from low temperature to high temperature, the heat resistance decreases, or the friction between the thermal head and the heat-resistant slip layer (48) causes a difference. There is a risk of occurrence. Further, there is a risk that unevenness of heat conduction occurs and unevenness of printing density occurs.

  Since it is desired to have stable lubricity in the range from room temperature to heat from the thermal head, among the at least two kinds of lubricants contained in the heat resistant slipping layer (48), At least one of them preferably has a melting point of 50 to 100 ° C., and the melting point of the other lubricants contained therein preferably has a difference of 30 ° C. or more. When a lubricant having a particularly high melting point is contained, there is a risk that the effect is not exhibited because the lubricant does not melt with heat from the thermal head. Also, if the difference in melting point of each lubricant is too small, the effects of each cannot be fully exhibited, or the slipperiness at a certain temperature may be biased, resulting in printing due to the friction difference between low energy printing and high energy printing. There is a possibility that a print defect such as uneven print density may occur due to creases, heat more than necessary, or heat more than necessary.

  The total amount of at least two or more lubricants contained in the heat resistant slipping layer (48) is preferably 5 to 25% by mass with respect to the heat resistant slipping layer (48). When the content of the lubricant is 5% by mass or less, there is a risk that the lubricity may not be sufficiently exhibited, or depending on the image, the thermal head may be stuck due to lack of the lubricant. Further, when the content of the lubricant is 25% by mass or more, there is a risk that the slipperiness may be imparted more than necessary or the lubricant may be melted and affect the printing.

  The heat-resistant slip layer 48 may contain inorganic particles. By including inorganic particles, irregularities are formed on the surface of the heat-resistant slip layer 48 and the contact area with the thermal head is reduced, so that the releasability of the thermal head during printing is improved. Moreover, heat resistance and cleaning properties can also be imparted. The inorganic particles are preferably those that are not deformed by heat from the thermal head. Specific examples include silica particles, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, talc, kaolin, and clay. Further, one kind of inorganic particles may be used, or two or more kinds thereof may be mixed and used. As for content of an inorganic particle, 2-30 mass% is preferable, More preferably, it is 3-20 mass%. When the content is less than 2% by mass, the cleaning effect of the thermal head is insufficient, and when it is more than 30% by mass, there is a risk that depending on the inorganic particles, the film strength of the heat resistant slipping layer itself may be reduced.

  Further, the heat resistant slip layer 48 may be used in combination with a crosslinking agent for the purpose of improving heat resistance. By containing a cross-linking agent, the heat resistance of the heat resistant slipping layer 48 is improved, and deformation of the substrate due to friction with the thermal head can be prevented. Examples of the cross-linking agent include polyisocyanates, which are used in combinations of acrylic, urethane, and polyester polyol resins, cellulose resins, and acetal resins.

Coating amount after drying of the heat-resistant lubricating layer 48 is preferably 0.2~2.6g / ^{m 2,} further 0.6~1.6g / ^{m 2} is more preferable. When the thickness of the heat-resistant slip layer (48) is smaller than 0.2 g / m ² , the heat resistance from the thermal head is inferior, and the support tends to shrink during printing. On the other hand, when it is larger than 2.6 g / m ² , heat from the thermal head is not sufficiently transmitted to the dye layer, and a printed matter having a desired density cannot be obtained.

  The undercoat layer 44 includes at least a water-soluble polymer and a vinylpyrrolidone-vinylcaprolactam copolymer, and is a coating solution for forming an undercoat layer by blending the water-soluble polymer and the vinylpyrrolidone-vinylcaprolactam copolymer. It is formed by preparing, applying and drying.

  In the undercoat layer 44, the water-soluble polymer and the vinylpyrrolidone-vinylcaprolactam copolymer are essential components, and in particular, the water-soluble polymer and the vinylpyrrolidone-vinylcaprolactam copolymer are the main components of the undercoat layer. It is preferable.

  Here, the main component means that, in addition to the water-soluble polymer and the vinylpyrrolidone-vinylcaprolactam copolymer, other components may be added unless the effects of the present invention are impaired. The total of the functional polymer and the vinylpyrrolidone-vinylcaprolactam copolymer is more than 50% by mass as viewed from the whole when the undercoat layer is formed, but is preferably 80% by mass or more.

  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. The polyvinyl alcohol here is generally obtained by saponifying polyvinyl acetate, and so-called partially saponified polyvinyl alcohol in which several tens percent of acetic acid groups remain, so that only a few percent of acetic acid groups remain. It includes up to fully 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.

  The vinyl pyrrolidone-vinyl caprolactam copolymer is considered to have been compensated by the vinyl caprolactam component for the poor heat resistance and moisture resistance of the water-soluble polymer component and the vinyl pyrrolidone component. The adhesiveness between the material 46 and the dye layer 42 is high, so that abnormal transfer in printing can be prevented, and the function of reducing the shine in the high density portion during high-speed printing can be exhibited. Here, in the vinylpyrrolidone-vinylcaprolactam copolymer, the polymerization ratio of vinylpyrrolidone and vinylcaprolactam is preferably (vinylpyrrolidone) / (vinylcaprolactam) = 8/2 to 2/8 in a molar ratio. In some cases, the above functions can be sufficiently exhibited.

  The mixing ratio of the water-soluble polymer and the vinylpyrrolidone-vinylcaprolactam copolymer is (water-soluble polymer) / (vinylpyrrolidone-vinylcaprolactam copolymer) = 8/2 to 2/8 on a mass basis. It is preferable. Further, when considering the transfer sensitivity at the time of high-speed printing and the adhesion to the base material 46 or the dye layer 42, it is preferably 7/3 to 3/7. By satisfying this range, the transfer sensitivity during high-speed printing is higher, high-density prints with less shine are obtained, and there is no abnormal transfer in printing even after storage under high temperature and high humidity. A sufficiently satisfactory print can be obtained.

  The undercoat layer 44 may contain known additives such as an isocyanate compound, a silane coupling agent, a dispersant, a viscosity modifier, and a stabilizer as long as the performance is not impaired.

The coating amount of the undercoat layer 44 after drying 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 is insufficient due to the deterioration at the time of laminating the dye layer, and there is a possibility that the adhesion to the substrate 46 or the dye layer 42 may be problematic. 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 risk that the transfer sensitivity at the time of high-speed printing will be insufficient.

The dye layer 42 may be a conventionally known one, and is formed by, for example, preparing a coating solution for forming a dye layer by blending a heat transferable dye, a binder, a solvent, etc., and applying and drying. The An appropriate coating amount of the dye layer 42 after drying is about 1.0 g / m ² . 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 substrate in the surface order.

  The heat transferable dye of the dye layer 42 is not particularly limited as long as it is a dye that melts, diffuses or sublimates and transfers due to heat. For example, as yellow components, 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 contained in the dye layer 42, any conventionally known resin binder can be used, and is not particularly limited. However, cellulose-based materials such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, and cellulose acetate are used. Examples thereof include vinyl resins such as resins, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, and polyacrylamide, polyester resins, styrene-acrylonitrile copolymer resins, and phenoxy resins.

  Here, the blending ratio of the dye and the binder in the dye layer 42 is preferably (dye) / (binder) = 10/100 to 300/100 on a mass basis. This is because when the ratio of (dye) / (binder) is less than 10/100, the amount of dye is too small and the color development sensitivity becomes insufficient, and a good thermal transfer image cannot be obtained, and this ratio is 300/100. If it exceeds the upper limit, the solubility of the dye in the binder is extremely lowered, so that when it becomes a thermal transfer recording medium, the storage stability is deteriorated and the dye is likely to precipitate. The dye layer may contain known additives such as an isocyanate compound, a silane coupling agent, a dispersant, a viscosity modifier, and a stabilizer as long as the performance is not impaired.

  The heat-resistant slip layer 48, the undercoat layer 44, and the dye layer 42 can be formed by applying and drying by a conventionally known application method. Examples of the application method include a gravure coating method, a screen printing method, a spray coating method, and a reverse roll coating method.

(Measuring method of static friction coefficient)
The static friction coefficient in the present invention is determined by using a HEIDON tribogear muse 94i (manufactured by Shinto Kagaku Co., Ltd.) friction coefficient measuring instrument, and the static friction coefficient between the heat-resistant sliding layers of the thermal transfer recording medium is 25 ° C to 100 ° C. Measurements were made at 5 ° C. intervals in the environment, and the absolute value of the difference between the maximum static friction coefficient and the static friction coefficient at 25 ° C. and 100 ° C. was determined.

  Hereinafter, Examples 1 to 9 and Comparative Examples 1 to 5 are produced and compared as specific examples according to the present invention. In the text, “part” is based on mass unless otherwise specified. Further, a lubricant whose melting point is described after the material name of the coating solution is a lubricant.

<Example 1>
As a base material 46, a polyethylene terephthalate film with a single-sided easy adhesion treatment of 4.5 μm is used, and a heat resistant slipping layer coating liquid-1 having the following composition is applied to the non-adhesive adhesion treated surface by a gravure coating method. After coating and drying so that the coating amount becomes 1.0 g / m ² , it is aged in a 40 ° C. environment for 1 week, and undercoat layer coating solution-1 having the following composition is applied to the surface with easy adhesion by a gravure coating method. The undercoat layer 44 was formed by applying and drying so that the coating amount after drying was 0.20 g / m ² . Subsequently, a dye layer coating solution having the following composition is applied onto the undercoat layer 44 by a gravure coating method so that the coating amount after drying is 0.70 g / m ² and dried. The layer 42 was formed, and the thermal transfer recording medium of Example 1 was obtained.

<Heat resistant slipping layer coating solution-1>
Acrylic polyol resin (solid content 50%) 12.5 parts Phosphate ester Melting point 15 ° C 0.3 part Phosphate ester Melting point 70 ° C 0.2 part Talc 6 parts 2,6-Tolylene diisocyanate prepolymer 4 parts Toluene 52 parts Methyl ethyl ketone 20 parts Ethyl acetate 5 parts

<Undercoat layer coating solution-1>
Polyvinylpyrrolidone 1.0 part Vinylpyrrolidone-vinylcaprolactam copolymer 4.0 parts [Copolymerization ratio (molar ratio): 3/7]
Pure water 76.0 parts Isopropyl alcohol 19.0 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 of Example 2 was performed in the same manner as in Example 1 except that the heat resistant slipping layer coating liquid was changed to the heat resistant slipping layer coating liquid-2 having the following composition. A medium was obtained.

Acrylic polyol resin (solid content 50%) 12.5 parts Phosphate ester Melting point 15 ° C. 3 parts Phosphate ester Melting point 70 ° C. 3 parts Talc 6 parts 2,6-tolylene diisocyanate prepolymer 4 parts Toluene 52 parts Methyl ethyl ketone 20 parts Acetic acid 5 parts ethyl

<Example 3>
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer of Example 3 was performed in the same manner as in Example 1 except that the heat resistant slipping layer coating liquid was changed to the heat resistant slipping layer coating liquid-3 having the following composition. A medium was obtained.

Acrylic polyol resin (solid content 50%) 12.5 parts sorbitan palmitate Melting point 46 ° C. 2 parts Zinc stearate Melting point 115 to 125 ° C. 1 part Talc 6 parts 2,6-tolylene diisocyanate prepolymer 4 parts Toluene 52 parts Methyl ethyl ketone 20 Part 5 parts ethyl acetate

<Example 4>
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer of Example 4 was performed in the same manner as in Example 1 except that the heat resistant slipping layer coating solution was changed to the heat resistant slipping layer coating solution-4 having the following composition. A medium was obtained.

Acrylic polyol resin (solid content 50%) 12.5 parts Phosphoric acid ester Melting point 70 ° C. 2 parts Erucic acid amide Melting point 79-85 ° C. 1 part Talc 6 parts 2,6-Tolylene diisocyanate prepolymer 4 parts Toluene 52 parts Methyl ethyl ketone 20 Part 5 parts ethyl acetate

<Example 5>
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer of Example 5 was performed in the same manner as in Example 1 except that the heat resistant slipping layer coating solution was changed to the heat resistant slipping layer coating solution-5 having the following composition. A medium was obtained.

Acrylic polyol resin (solid content 50%) 12.5 parts Phosphate ester Melting point 15 ° C 0.5 part Phosphate ester Melting point 70 ° C 0.5 part Talc 6 parts 2,6-Tolylene diisocyanate prepolymer 4 parts Toluene 52 parts Methyl ethyl ketone 20 parts Ethyl acetate 5 parts

<Example 6>
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer of Example 6 was performed in the same manner as in Example 1 except that the heat resistant slipping layer coating solution was changed to the heat resistant slipping layer coating solution-6 having the following composition. A medium was obtained.

Acrylic polyol resin (solid content 50%) 12.5 parts Phosphate ester Melting point 15 ° C. 3 parts Phosphate ester Melting point 70 ° C. 2 parts Talc 6 parts 2,6-tolylene diisocyanate prepolymer 4 parts Toluene 52 parts Methyl ethyl ketone 20 parts Acetic acid 5 parts ethyl

<Example 7>
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer of Example 7 was performed in the same manner as in Example 1 except that the heat resistant slipping layer coating liquid was changed to the heat resistant slipping layer coating liquid-7 having the following composition. A medium was obtained.

Acrylic polyol resin (solid content 50%) 12.5 parts Phosphate ester Melting point 15 ° C. 2 parts Phosphate ester Melting point 70 ° C. 1 part Talc 6 parts 2,6-Tolylene diisocyanate prepolymer 4 parts Toluene 52 parts Methyl ethyl ketone 20 parts Acetic acid 5 parts ethyl

<Example 8>
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer of Example 8 was performed in the same manner as in Example 1 except that the heat resistant slipping layer coating solution was changed to the heat resistant slipping layer coating solution-8 having the following composition. A medium was obtained.

Acrylic polyol resin (solid content 50%) 12.5 parts Phosphate ester Melting point 15 ° C 2 parts Phosphate ester Melting point 70 ° C 0.5 part Zinc stearate Melting point 115 to 125 ° C 0.5 part Talc 6 parts 2,6- Tolylene diisocyanate prepolymer 4 parts Toluene 52 parts Methyl ethyl ketone 20 parts Ethyl acetate 5 parts

<Example 9>
In the thermal transfer recording medium produced in Example 8, the thermal recording transfer medium of Example 9 was obtained in the same manner as in Example 8 except that the undercoat layer 44 was changed to the undercoat layer coating solution-2 of the following composition. It was.

<Undercoat layer coating solution-2>
Polyvinyl alcohol 1.0 part Vinylpyrrolidone-vinylcaprolactam copolymer 4.0 parts
[Copolymerization ratio (molar ratio): 3/7]
Pure water 76.0 parts Isopropyl alcohol 19.0 parts

<Comparative Example 1>
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer of Comparative Example 1 was performed in the same manner as in Example 1 except that the heat resistant slipping layer coating liquid was changed to the heat resistant slipping layer coating liquid-9 having the following composition. A medium was obtained.

Acrylic polyol resin (solid content 50%) 12.5 parts Zinc stearate Melting point 100-105 ° C 3 parts Talc 6 parts 2,6-tolylene diisocyanate prepolymer 4 parts Toluene 52 parts Methyl ethyl ketone 20 parts Ethyl acetate 5 parts

<Comparative example 2>
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer of Comparative Example 2 was performed in the same manner as in Example 1 except that the heat resistant slipping layer coating solution was changed to the heat resistant slipping layer coating solution-10 having the following composition. A medium was obtained.

Acrylic polyol resin (solid content 50%) 12.5 parts Phosphate ester Melting point 70 2 parts Glyceryl stearate Melting point 70 ° C 1 part Talc 6 parts 2,6-Tolylene diisocyanate prepolymer 4 parts Toluene 52 parts Methyl ethyl ketone 20 parts Ethyl acetate 5 copies

<Comparative Example 3>
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer of Comparative Example 3 was performed in the same manner as in Example 1 except that the heat resistant slipping layer coating solution was changed to the heat resistant slipping layer coating solution-11 having the following composition. A medium was obtained. The absolute value of the difference between the static friction coefficients between 25 ° C. and 100 ° C. was 0.056.

Acrylic polyol resin (solid content 50%) 12.5 parts Zinc stearate Melting point 115-125 ° C 2 parts Magnesium stearate Melting point 155 ° C 1 part Talc 6 parts 2,6-tolylene diisocyanate prepolymer 4 parts Toluene 52 parts Methyl ethyl ketone 20 Part 5 parts ethyl acetate

<Comparative example 4>
In the thermal transfer recording medium produced in Example 8, the thermal recording transfer medium of Comparative Example 4 was prepared in the same manner as in Example 8 except that the undercoat layer coating solution was changed to the undercoat layer coating solution-2 of the following composition. Obtained.

<Undercoat layer coating solution-2>
Polyvinylpyrrolidone 5.0 parts Pure water 76.0 parts Isopropyl alcohol 19.0 parts

<Comparative Example 5>
In the thermal transfer recording medium produced in Example 8, the thermal recording transfer medium of Comparative Example 5 was obtained in the same manner as in Example 8 except that the undercoat layer 44 was not provided.

<Print evaluation>
Table 1 shows the results of printing the thermal transfer recording media of Examples 1 to 9 and Comparative Examples 1 to 5 with a thermal simulator, and evaluating the maximum reflection density, printing wrinkles, printing defects, and head contamination. The maximum reflection density is a value measured with X-Rite 528.

  The printing conditions are as follows.

Printing environment: 23 ° C, 50% RH
Applied voltage: 29V
Line cycle: 0.7msec
Print density: main scanning 300 dpi sub-scanning 300 dpi

[Printing Jiwa]
◎: No printing wrinkles ○: Slightly small printing wrinkles △: Slight printing wrinkles ×: Many printing wrinkles [Print density unevenness]
A: There is almost no density unevenness; ○: There is a slight density unevenness; Δ: There is a density unevenness (slightly noticeable)
×: Concentration unevenness (conspicuous)
[Head dirt]
○: Good without problems
△: There is no problem, but it is a little bad ×: There is a problem [shine]
◎; No shine ○; Slightly shine in some places △; With shine (slightly noticeable)
×: There is shine (conspicuous)

(Evaluation results)
It was found that the thermal transfer recording media of Examples 1 to 9 of the present invention were able to obtain printed matter without problems in terms of printing wrinkles and density unevenness, and the maximum reflection density was also good. In particular, in Examples 7 to 9, the absolute value of the difference between the static friction coefficients of 25 ° C. and 100 ° C. was small, and good results were obtained in both printing wrinkles and density unevenness. Therefore, the heat-sensitive transfer recording medium of the present invention having a low coefficient of static friction coefficient in any temperature environment by containing two or more lubricants having different melting points of 5 ° C. or more has stable lubricity and heat conduction at any temperature and printing energy. It has been confirmed that it has sex.

  In Example 9, it was found that the maximum reflection density was increased by using polyvinyl alcohol as the water-soluble polymer in the undercoat layer 44. Therefore, it was found that the water-soluble polymer in the undercoat layer 44 is more preferably polyvinyl alcohol.

  Regarding Example 1, it was found that there was no problem with respect to the maximum reflection density, printing wrinkles, and density unevenness, but it was slightly inferior to the others. Moreover, it turned out that the maximum value of a static friction coefficient is high. Therefore, it was found that the amount of lubricant was slightly insufficient. Moreover, about Example 2, although the favorable result was obtained by the maximum reflection density and the printing wrinkle, it turned out that there is not a big difference with Examples 6-9 for the largest amount of lubricant additions. Further, the density unevenness did not give a very good result, and the head contamination was deteriorated. Because of this, the content of the lubricant was slightly high, so the lubricant melted more than necessary due to the heat of the thermal head, and even though the slipperiness was good to some extent and print wrinkles did not occur, density unevenness appeared I understood it. Therefore, it was found that the total amount of the lubricant is preferably 5 to 25% by mass with respect to the heat resistant slipping layer.

  Regarding Examples 3 and 4, a slight print wrinkle was generated. For Example 3, the lubricant that is considered to exhibit lubricity during medium energy printing is not included, and for Example 4, only the lubricant that is considered to exhibit lubricity during medium energy printing is included. It was found that stable slipperiness at any temperature and printing energy could not be obtained. For this reason, it has been found that it is preferable to include a lubricant having a melting point that can cope with medium-energy printing to some extent and a lubricant having a certain melting point difference so as to show stable lubricity at any temperature and printing energy.

  On the other hand, in Comparative Example 1 in which only one type of lubricant is contained in the heat-resistant slip layer 48, the absolute value of the difference between the static friction coefficients at 25 ° C. and 100 ° C. is large, and it is found that printing wrinkles and density unevenness are worsened. It was.

  Further, in Comparative Example 2 containing two kinds of lubricants having the same melting point, it was found that the maximum value of the static friction coefficient was slightly high, and good results were not obtained in printing wrinkles and density unevenness. From the above, it was found that in both Comparative Examples 1 and 2, the slipperiness at a certain temperature was biased and affected the running property of the ribbon. In Comparative Example 3 in which the absolute value of the difference between the static friction coefficients at 25 ° C. and 100 ° C. was 0.04 or more, it was confirmed that printing wrinkles and density unevenness were worsened.

In Comparative Example 4 in which the undercoat layer 44 contains only polyvinyl pyrrolidone, it was also found that the maximum reflection density was low and shine was generated. Further, in Comparative Example 5 in which the undercoat layer itself was not provided, it was found that the maximum reflection density was significantly reduced, and it was confirmed that the maximum reflection density could be improved by the undercoat layer 44.

  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.

  According to the heat-sensitive transfer recording medium of the present invention, good results can be obtained in printing wrinkles and density unevenness, so that it is possible to obtain printed matter with excellent quality. It can be used for output of facial photos, composite photos at amusement facilities, etc., and it can be used for a wide range of printer speeds due to its stable lubricity at all temperatures and printing energies. Can be expected.

42 ... Dye layer 44 ... Undercoat layer 46 ... Base material 48 ... Heat-resistant slip layer 50 ... Thermal transfer recording medium

Claims (6)

In the heat-sensitive transfer recording medium provided with a heat-resistant slipping layer on one surface of the substrate, and provided with an undercoat layer and a dye layer in this order on the other surface of the substrate,
The undercoat layer includes at least a water-soluble polymer and a vinylpyrrolidone-vinylcaprolactam copolymer, and the heat resistant slipping layer includes at least two kinds of lubricants having melting points of 5 ° C. or more, and includes 25 ° C. A thermal transfer recording medium having a static friction coefficient of 0.4 or less in an environment of -100 ° C.   The thermal transfer recording medium according to claim 1, wherein the heat-resistant slipping layer has an absolute value of a difference between a static friction coefficient at 25 ° C and a static friction coefficient at 100 ° C of 0.04 or less.   3. The thermal transfer recording medium according to claim 1, wherein the total amount of the lubricant contained in the heat-resistant slipping layer is 5 to 25 mass% with respect to the heat-resistant slipping layer.   4. The thermal transfer recording according to claim 1, wherein at least one of the lubricants contained in the heat resistant slipping layer has a melting point of 50 to 100 ° C. 5. Medium.   5. The thermal transfer recording medium according to claim 1, wherein melting points of the lubricants contained in two or more kinds of the heat resistant slipping layer have a difference of 30 ° C. or more.   6. The thermal transfer recording medium according to claim 1, wherein the water-soluble polymer contained in the undercoat layer is polyvinyl alcohol.

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