JP2000272251A - Heat transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a thermal damage to a thin film substrate and prevent unevenness in print due to heat wrinkles of a substrate by suppressing a thermal history of substrate to a minimum and changing a printing process of heat resistant lubricating layer-aging-dye layer to a process of heat resistant lubricating layer.dye layer inline printing. SOLUTION: In the heat transfer sheet having a biaxially stretched polyester film 1-5 μm in thickness (easily-adhesive layer treatment, when required) as a substrate, wherein a heat resistant lubricating layer is provided on one side thereof, while a heat sublimation dye layer is provided on the other side, a binder resin of the heat resistant lubricating layer contains, as a principal component, a styrene/acrylonitrile copolymer, and a lubricant contains a multivalent metallic salt of an alkyl phosphate and at least two kinds of or the same kind of heat resistant particles having different diameters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer material used for a thermal printer, and more particularly, to a thermal transfer sheet which gives a high quality image corresponding to high speed and high sensitivity printing.

[0002]

2. Description of the Related Art Conventionally, a biaxially stretched polyester film has been used as a substrate as a thermal transfer sheet, having a heat-resistant lubricating layer on one side of the substrate, and a sublimable dye and a binder on the other side. A sublimation type thermal transfer sheet provided with a dye layer made of a resin is known. In general, a color image is formed by heating an image from a heat-resistant lubricating layer side by a thermal head and transferring the dye of the heat-sublimable dye layer to a transfer-receiving material. In general, a thermal transfer sheet is composed of a Ye, Mg, Cy layer (a Bk layer and a protective layer as necessary) in a face-sequential manner or a monocolor ribbon, and there are two types of printing methods: a line type and a serial type.

[0003]

In recent years, in order to shorten the printing time of a printer, a printing method has been devised to make it possible to cope with high-speed printing. Furthermore, in order to support mobile device applications, it is essential to reduce the size and power consumption of printers, and thinner thermal transfer sheets have been required. Usually, the thickness of the base material used for the thermal transfer sheet is 5 to 6 μm, but a remarkable sensitivity UP is realized by thinning the base material to 1 to 5 μm,
Problems that did not occur with conventional thicknesses have become apparent.
In particular, the thermal damage of the thin film substrate is large, and the printability is poor.For example, thermal wrinkles of the substrate cause printing unevenness, decrease in dimensional stability due to heat shrinkage of the substrate, and even to post-processing suitability. Have an effect. In general, a sublimation type thermal transfer sheet requires high heat resistance and lubricity, and therefore often uses a thermosetting resin, requires an aging treatment, and inevitably causes thermal damage to a substrate.

[0004]

In other words, it is important to minimize the thermal history of the thin film substrate, and the heat resistant slip layer / dye layer is formed by the steps of heat resistant slip layer printing → aging treatment → dye layer printing. It was found that the above problem could be solved by changing to inline printing.

[0005]

The thin film base material is composed mainly of a styrene / acrylonitrile copolymer as a binder resin, a polyvalent metal salt of an alkyl phosphate as a lubricant, and at least two kinds of particles having different particle sizes.
Alternatively, by using a heat-resistant lubricating layer containing the same type of heat-resistant particles, a print quality is excellent and a high-quality full-color image can be provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in detail with reference to preferred embodiments. The substrate constituting the thermal transfer ribbon of the present invention may be any one having a conventionally known degree of heat resistance and strength, such as polyethylene terephthalate, 1,4-polycyclohexylene dimethylene terephthalate, polyethylene naphthalate, and polyphenylene sal. Fido, polystyrene, aramid, polypropylene,
Cellulose derivatives such as polysulfone, polycarbonate, polyvinyl alcohol, and cellulose acetate; films such as polyethylene, polyvinyl chloride, nylon, polyimide, and ionomer; papers such as condenser paper and paraffin paper; nonwoven fabric; or composite of paper and nonwoven fabric with resin It may be a body.

As a film forming method, a thermoplastic polymer is dried, supplied to an extruder, heated to a temperature not lower than the melting point of the resin, discharged quantitatively from a T-die die, and cooled with a high voltage applied. To obtain an unstretched film. The unstretched film is heated by a heating roll group at 80 to 130 ° C., stretched 4 to 8 times in the MD direction, and stretched to 20 to 5 times.
Cool with rolls at 0 ° C. Here, in order to suppress the thickness unevenness in the MD direction to within ± 5%, it is preferable to carry out longitudinal stretching in at least two steps, and the first-stage longitudinal stretching is performed at a stretching temperature of Tg + 10 to Tg + 55 ° C. of the polymer used, preferably Tg + 30 to Tg + 45 ° C., stretching ratio is 1.1
２．５2.5-fold, preferably 1.5-2.3-fold. In order to enhance the thickness uniformity, when extruding from a T-die, the temperature of the polymer should be lower than the polymer melting end temperature.
The temperature may be set to a temperature higher than the temperature dropping temperature for crystallization to suppress thickness unevenness due to film vibration during extrusion. Next, the longitudinal stretching conditions (stretching ratio distribution, temperature) in the second and subsequent stages are optimized, and after the first longitudinal stretching, a hot roll treatment of Tg + 15 to Tg + 60 ° C., preferably Tg + 30 to Tg + 55 ° C. is performed, whereby the stretchability is improved. Is improved, and is effective in performing longitudinal stretching at a total longitudinal magnification of 4 to 8 times. Incidentally, when finally obtaining a thermal transfer ribbon, in order to improve the adhesiveness between the base film and the thermal transfer color material layer, after longitudinal stretching, polyester-based resin or acrylic-based resin each alone, or by mixing them, An easily adhesive layer cured with a melamine-based crosslinking agent may be applied. However, the coating amount of the easily adhesive layer is preferably 0.1 g / m ² or less, and the uneven coating amount is desirably within the range of ± 15% in both the MD and TD directions.

Subsequently, the film is guided to a tenter and preheated in a hot air atmosphere heated to 80 to 130 ° C. while holding both ends of the longitudinally stretched film with clips, and stretched 3 to 5 times in the TD direction. Heat setting and relaxation treatment may be performed accordingly. The heat setting temperature here is 220 to 255 ° C, preferably 230 to 250 ° C. To obtain a film having excellent thermal dimensional stability, the relaxation temperature is 100 to 220 ° C.
It is preferable to optimize each processing condition (temperature, time, relaxation rate). The thickness of the substrate is 1 to 5 μm,
The thickness unevenness is preferably within ± 10% in both the MD and TD directions.

In the case where an easy-adhesion layer is provided after the formation of the base material, preferred resins include polyester resins, acrylic resins, urethane resins, and alkyd resins, and have an adhesive property to the base material or the thermal transfer color material layer, or Melamine-based compounds, isocyanate-based compounds,
It is desirable to use in combination with an epoxy compound, a compound containing an oxazoline group, a chelate compound, or the like. Acetone, methyl ethyl ketone, toluene, alcohol, solvents such as xylene or water selected from the above materials to suit the coating suitability, or dissolved or dispersed in water to create a coating liquid,
A method of applying, drying, and solidifying the coating liquid with a coating means such as a gravure coater, a die coater, a roll coater, a wire bar or the like to form a film. The coating amount of the easily adhesive layer is preferably 0.1 g / m ² or less, and the uneven coating amount is preferably within ± 15% in the MD and TD directions.

The heat-resistant lubricating layer formed on one surface of the base material is a binder resin containing a styrene / acrylonitrile copolymer as a main component, a polyvalent metal salt of an alkyl phosphate as a lubricant, and at least two kinds of particles having different particle sizes. Alternatively, it is characterized by being formed containing the same kind of heat-resistant particles. The styrene / acrylonitrile copolymer of the binder resin used in the present invention is obtained by copolymerizing styrene and acrylonitrile, and includes, for example, Sebian AD,
Various grades such as Sebian LD and Sebian NA (manufactured by Daicel Chemical) can be easily obtained from the market,
In addition, any of them can be used in the present invention and can be easily produced according to a conventional method. A styrene / acrylonitrile copolymer suitable for the purpose of the present invention has a molecular weight of 100,000 to 200,000, preferably 150 to 190,000, and an acrylonitrile content of 20 to 40.
Mol%, preferably 25 to 30 mol%, and those having a softening temperature of 400 ° C. or higher as determined by differential thermal analysis are favorable in terms of dissolution stability in organic solvents and heat resistance.

[0011] The styrene / acrylonitrile copolymer has insufficient adhesion to a substrate such as polyethylene terephthalate, polyethylene naphthalate, or a composite thereof. Therefore, it is desirable to copolymerize a monomer having a functional group of several mol% (for example, methacrylic acid) during the production of the styrene / acrylonitrile copolymer. On the other hand, when the styrene / acrylonitrile copolymer is used as a mixture, the ratio of the adhesive resin is preferably 1 to 30 parts by weight based on 100 parts by weight of the styrene / acrylonitrile copolymer. Further, within the range not hindering the object of the present invention, for example, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose,
Cellulose resins such as hydroxypropylcellulose, methylcellulose, cellulose acetate, and cellulose acetate butyrate; vinyl resins such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, polyacrylamide, acrylonitrile-styrene copolymer, and polyester. Resins, polyurethane resins, silicone-modified or fluorine-modified urethanes can be used in combination if they are used in small amounts. Another method is to provide an adhesive resin as a primer layer between the base material and the heat-resistant lubricating layer, and the thickness of the primer layer is preferably 0.01 to 0.1 μm. A preferred resin is an amorphous linear saturated polyester resin having a Tg of 50 ° C. or higher. For example, various resins such as Elitel (product of Unitika), Polyester (product of Nippon Synthetic Chemical), Byron (product of Toyobo) and the like can be used. Grades are readily available from the market and can be used in any of the present invention and can be easily manufactured according to conventional methods.

As the lubricant or heat releasing agent used in the present invention, wax, higher fatty acid amide, higher fatty acid ester, surfactant, higher fatty acid metal salt and the like can be mentioned.
Lubricants suitable for the present invention are polyvalent metal salts of alkyl phosphates, known as additives for plastics,
For example, LTB1830, SA1000, SZ2000
(All of which are manufactured by Sakai Chemical Co., Ltd.) are easily available from the market in various grades. The alkyl group of the alkyl phosphate ester has 12 or more carbon atoms such as a cetyl group, a lauryl group, and a stearyl group, and the polyvalent metal salt includes lithium, barium, calcium, magnesium, zinc, and aluminum. On the other hand, the amount of the lubricant is preferably 10 to 150 parts by weight, and a conductive agent such as carbon black and an antistatic agent such as a quaternary ammonium salt and a phosphoric acid ester can be added to impart antistatic properties.

Various heat-resistant particles used in the present invention are known per se. For example, hydrotalsalt DHT-4A
(Manufactured by Kyowa Chemical Co., Ltd.), talc microace (manufactured by Nippon Talc), Teflon Lubron L-2 (manufactured by Daikin Industries), graphite fluoride SCP-10 (manufactured by Sanbo Kagaku), graphite A
Fine particles such as T40S (manufactured by Oriental Sangyo) or silica, calcium carbonate, molybdenum disulfide, urea resin crosslinked powder, melamine resin crosslinked powder, styrene / acrylic resin crosslinked powder, amino resin crosslinked powder, silicone powder, wood powder, and the like. . In the present invention, at least two kinds or different kinds of heat-resistant particles having different particle diameters are mixed and used, and these particle diameters are preferably selected according to the thickness of the heat-resistant lubricating layer to be formed. Assuming that the thickness of the heat-resistant lubricating layer is X, the particle diameter of the large particles is preferably in the range of 0.5X to X. If the thickness is less than half, sufficient heat resistance cannot be obtained. Head wear increases. It is important for the small particles to fill the gaps between the large particles. Therefore, the particle size of the small particles is preferably equal to or smaller than 1/2 of the large particles. If the particle size is larger than this, it becomes difficult to fill the gaps between the large particles. The ratio of the heat-resistant particles in the layer decreases, which causes a decrease in the heat resistance of the coating film. The heat-resistant particles are the binder resin 1
The weight ratio of large particles / small particles is preferably 1/4 to 4/1 with respect to 00 parts by weight.

As a method of forming the heat-resistant lubricating layer, the above-mentioned materials are dissolved or dispersed in water or a solvent such as acetone, methyl ethyl ketone, toluene, xylene, alcohol or the like selected so as to be suitable for coating. Create a working fluid and apply this coating fluid to a gravure coater, die coater,
A method of forming a film by applying, drying, and solidifying by a conventional coating means such as a roll coater or a wire bar may be used.
Coating amount of the heat-resistant slipping layer on a solids basis 1.0 g / m ² or less, preferably heat-resistant lubricating layer is obtained with sufficient performance at coat weight in the 0.1 to 0.5 g / m ² range It is desirable that the unevenness of the coating amount be within ± 10% in the MD and TD directions.

The heat sublimable dye layer formed on the other surface of the base film is composed of a binder resin and fine particles such as a sublimable dye and a filler. As the dye used in the heat sublimable dye layer, any dye conventionally used in a known thermal transfer ribbon can be used in the present invention, and is not particularly limited. For example, a preferred dye is
MS Red G, Macro Re as a red dye
dViolet R, Ceres Red 7B, Sa
maron Red HBSL, Resolin R
ed F3BS and the like, and yellow dyes include holon brilliant yellow 6GL and PTY-5.
2, Macrolex Yellow 6G, etc., and as the blue dye, Kayaset Blue 714, Waxolin Blue AP-FW, Holon Brilliant Blue SR,
MS Blue 100 and the like.

Preferred examples of the binder resin for supporting the above dye include cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate and cellulose acetate butyrate, and polyvinyl alcohol. , Polyvinyl acetate,
Polyvinyl butyral, polyvinyl acetoacetal,
Vinyl resins such as polyvinylpyrrolidone, poly (meth)
Acrylic resins such as acrylate and poly (meth) acrylamide, polyurethane-based resins, polyamide-based resins, polyester-based resins, and the like can be mentioned.
Cellulose-based, vinyl-based, acrylic-based, urethane-based, and polyester-based resins are preferred in terms of heat resistance, dye transfer properties, and the like.

The dye layer is formed by adding the above-mentioned dye and binder resin and, if necessary, additives such as a releasing agent and inorganic fine particles to one surface of the base material, and adding toluene, ethyl ethyl, and the like. Gravure printing, die coating printing, bar coating printing, dissolving in a suitable organic solvent such as ketone, isopropyl alcohol, ethanol, cyclohexanone, DMF, or dispersing in an organic solvent or water
It can be formed by applying and drying by means such as screen printing or reverse roll coating printing using a gravure plate. The coating amount of the dye layer is 3.0 g / m ² or less, preferably 0.5 to 1.5 g / m ^{2 based} on the solid content.
The coating amount is m ² , and the coating amount unevenness is preferably within ± 10% in the MD and TD directions. The sublimable dye in the dye layer is present in an amount of 5 to 90% by weight, preferably 10 to 70% by weight of the weight of the dye layer. When the desired image is a monocolor, the dye layer to be formed is formed by selecting one color from the dyes,
If the desired image is a full-color image, a dye layer of yellow, magenta, and cyan (and, if necessary, a black or protective layer) is formed.

The thermal transfer image-receiving paper used to form an image using the above-described thermal transfer ribbon may be any as long as its recording surface has a dye-accepting property for the dye. In the case of paper, metal, glass, synthetic resin, or the like having no property, a dye receiving layer may be formed on at least one surface thereof. As a printer used when performing thermal transfer using the thermal transfer ribbon and the image receiving sheet, a known thermal transfer printer can be used as it is, and is not particularly limited.

[0019]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following description, parts and percentages are by weight unless otherwise specified.

Example 1 <Thermal transfer sheet> A heat-resistant lubricating layer ink of the following composition 1 was applied to one surface of a biaxially stretched polyethylene terephthalate having a substrate thickness of 4 μm by gravure printing to have a coating amount of about 0.1.
The composition was applied so as to be 3 g / m ² to form a heat-resistant lubricating layer. On the other side, a dye layer ink having the following composition A to C is applied by gravure printing so that the Ye, Mg, and Cy layers are coated in a face-sequential manner so that the coating amount after drying is about 0.5 g / m ² , and then drying is performed. Temperature 100-110 ° C, dry hood residence time 3
Drying was performed under the condition of 0 second to obtain a thermal transfer sheet of the present invention. Heat-resistant lubricating layer ink composition 1 part by weight Styrene / acrylonitrile copolymer (manufactured by Daicel Chemical Industries, Sebian AD) 6.0 parts Linear saturated polyester resin (manufactured by Unitika, Elitel UE3200) 0.3 part Zinc stearyl phosphate (Sakai Chemical) 3.0 parts urea resin cross-linked powder (Nippon Kasei Co., Ltd., organic filler / particle size 0.14 μm) 3.0 parts Melamine resin cross-linked powder (Nippon Shokubai Chemical, Eposter S / 0.30 μm particle size) 1.5 parts Methyl ethyl ketone 43.1 parts Toluene 43.1 parts Dye layer ink composition A (Ye) parts by weight C.I. I. Disperse Yellow 201 3.2 parts

Embedded image 4.8 parts Polyvinyl acetoacetal resin (KS-5, manufactured by Sekisui Chemical) 3.5 parts Polyethylene wax (MF8F, manufactured by ASTOR WAX. CO.) 0.3 parts Methyl ethyl ketone 44.2 parts Toluene 44.2 parts Dye layer ink Composition B (Mg) parts by weight C. I. Disperse Violet 26 3.4 parts C.I. I. Disperse Red 60 2.3 parts

Embedded image 2.6 parts Polyvinyl acetoacetal resin (manufactured by Sekisui Chemical, KS-5) 3.5 parts Polyethylene wax (manufactured by ASTOR WAX. CO., MF8F) 0.3 parts Methyl ethyl ketone 44.1 parts Toluene 44.1 parts Dye layer ink Composition C (Cy) parts by weight I. Solvent Blue 3.1 parts C.I. I. Disperse Blue 354 1.5 parts

Embedded image 3.1 parts Polyvinylacetoacetal resin (manufactured by Sekisui Chemical, KS-5) 3.5 parts Polyethylene wax (manufactured by ASTOR WAX.CO., MF8F) 0.3 parts Methyl ethyl ketone 44.4 parts Toluene 44.4 parts <transferred Image receiving paper> A 150 μm-thick synthetic paper (YUPO FPG # 150 manufactured by Oji Oil Chemical Co., Ltd.) was used as a base material, and the back layer ink having the following composition D was dried on one surface by a wire bar coating method. After coating so as to obtain about 2.5 g / m ² , the coating was dried at 130 ° C. for 1 minute, and the coated surface of the image receiving layer ink having the following composition E was dried in the same manner as described above. After coating so as to be about 0 g / m ² ,
After drying at 130 ° C. for 3 minutes, a transfer receiving paper was prepared. Back layer ink composition D parts by weight Cellulose acetate (L-30, manufactured by Daicel Chemical Industries) 8.0 parts Vinyl acetate resin (Esnil C-2C, manufactured by Sekisui Chemical Co., Ltd.) 2.0 parts Microsilica (Mizukasil, manufactured by Mizusawa Chemical Industries, Ltd.) P73) 3.0 parts Nylon filler (manufactured by Shinto Paint Co., Ltd., MW-330) 2.0 parts Ethyl acetate 180.0 parts Image receiving layer ink composition E parts by weight Polyester resin (Toyobo Co., Byron 200) 20.0 Part Amino-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 part Epoxy-modified silicone (X-22-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 part Methyl ethyl ketone 50.0 parts Toluene 50.0 parts

Example 2 <Thermal Transfer Sheet> A heat-resistant lubricating layer ink of the following composition 2 was coated on one surface of a biaxially stretched polyethylene terephthalate having a substrate thickness of 3 μm by gravure printing to have a coating amount of about 0.1.
The composition was applied so as to be 3 g / m ² to form a heat-resistant lubricating layer. On the other side, the dye layer inks of the above-described compositions A to C were applied by gravure printing to form a Ye, Mg, and Cy layer in a sequential manner so that the coating amount after drying was about 0.5 g / m ^2. Drying was performed under the conditions of 100 to 110 ° C and a residence time of the drying hood of 30 seconds to obtain a thermal transfer sheet of the present invention. Heat-resistant lubricating layer ink composition 2 parts by weight Styrene / acrylonitrile copolymer (manufactured by Daicel Chemical Industries, Sebian LD) 6.0 parts Linear saturated polyester resin (manufactured by Toyobo, Byron 200) 0.3 parts Aluminum stearyl phosphate (Sakai Chemical) 4.5 parts polyethylene wax (manufactured by Adeka Argus, Mark FE113) 1.0 part fluorocarbon (manufactured by Accel Plastics, Moldbits F57) 1.5 parts methyl ethyl ketone 43.6 parts toluene 43.6 parts

Example 3 Biaxially stretched polyethylene naphthalate having a substrate thickness of 2.5 μm
The heat-resistant lubricating layer ink of the following composition 3
(A) The coating amount after drying by printing is about 0.5 g / m ^TwoNana
To form a heat-resistant lubricating layer. On the other side, the pair
Ye, M
g, Cy layer is dried in a plane-sequential manner to a coating amount of about 0.5 g /
m^TwoAfter applying so that the drying temperature is 100 to 110
The present invention is dried under the conditions of 30 ° C. and a drying hood residence time of 30 seconds.
Was obtained.Heat resistant slip layer ink composition 3 Parts by weight Styrene / acrylonitrile copolymer (manufactured by Daicel Chemical Industries, Sebian NA) 6.0 parts amorphous linear saturated polyester resin (manufactured by Nippon Synthetic Chemical Co., Polyester TP 220) 0.2 parts calcium stearyl phosphate (Sakai Chemical) 4.5 parts Melamine resin crosslinked powder (Nippon Shokubai Chemical Co., Ltd., Eposter S / particle diameter 0.30 μm) 1.5 parts Acrylic resin crosslinked powder (Soken Chemical Co., Ltd., GL 300 / particle diameter 0.10 μm) 3.0 parts Methyl ethyl ketone 42.4 parts Toluene 42.4 parts

Comparative Example 1 A heat-resistant lubricating layer ink of the following composition 4 was coated on one surface of a biaxially stretched polyethylene terephthalate having a substrate thickness of 4 μm by gravure printing so that the coating amount after drying was about 1.0 g / m ^2. , And then heat-aged to perform a curing treatment to form a heat-resistant lubricating layer. On the other side, the dye layer inks of the compositions A to C are applied by gravure printing in a Ye, Mg, and Cy layer order, so that the coating amount after drying is about 0.5 g / m ^2, and then the drying temperature is 100. Drying was performed under the conditions of -110 ° C and a residence time of the drying hood of 30 seconds to obtain a thermal transfer sheet. Heat-resistant lubricating layer ink composition 4 parts by weight Polyvinyl butyral resin (manufactured by Sekisui Chemical, S-LEC BX-1) 3.6 parts Polyisocyanate (manufactured by Dainippon Ink and Chemicals, Burnock D-750-45) 19.2 parts phosphorus Acid ester (Daiichi Kogyo Seiyaku, Plysurf A-208S) 2.9 parts Talc (Nippon Talc, Microace L-1 / P-3) 0.6 parts Methyl ethyl ketone 33.0 parts Toluene 33.0 parts

Comparative Example 2 Biaxially stretched polyethylene naphthalate having a substrate thickness of 2.5 μm
The heat-resistant lubricating layer ink of composition 4 is coated on one surface of
(A) The coating amount after drying by printing is about 0.5 g / m ^TwoNana
After application, heat aging and curing treatment,
A thermal lubricating layer was formed. On the other side, a dye layer of the above composition A to C
Surface order of Ye, Mg, Cy layer by gravure printing of ink
Next, the coating amount after drying is about 0.5 g / m^TwoTo be
After applying, drying temperature 100 ~ 110 ° C, drying hood stay
Drying was performed under the conditions of a retention time of 30 seconds to obtain a thermal transfer sheet.

(Evaluation method) Dimensional stability The dimensions of the base film in the width direction before and after printing are measured, and the rate of change (%) in the width direction of the base material is calculated to verify the effect on printing. did. Printing Evaluation YMC full solid printing was performed using a commercially available A6 printer, and the printing quality was visually checked.

(Result)

[Table 1]

[0027]

As described above, according to the present invention, a binder resin is mainly composed of a styrene / acrylonitrile copolymer, a polyvalent metal salt of an alkyl phosphate is used as a lubricant, and at least two kinds of particles having different particle diameters are used. Alternatively, by using a heat-resistant lubricating layer containing the same kind of heat-resistant particles, a high-quality full-color image excellent in printability can be provided.

Claims (6)

[Claims] 1. A heat transfer sheet having a biaxially stretched polyester film of 1 to 5 μm as a base material, a heat-resistant lubricating layer provided on one surface and a heat-sublimable dye layer on the other surface. A thermal transfer sheet comprising a binder resin containing a styrene / acrylonitrile copolymer as a main component and a lubricant containing a polyvalent metal salt of an alkyl phosphate, at least two kinds of particles having different particle diameters, or the same kind of heat-resistant particles. 2. The thermal transfer sheet according to claim 1, wherein the substrate is polyethylene terephthalate, polyethylene naphthalate, or a composite thereof. 3. A primer layer comprising a polyester resin as a main component for providing adhesion between a substrate and a heat-resistant lubricating layer, or the polyester resin is contained in a binder resin. The thermal transfer sheet according to claim 1, wherein 4. The multivalent metal salt of an alkyl phosphate ester as a lubricant has an alkyl group having 12 or more carbon atoms, and is a metal salt of lithium, an alkaline earth metal, zinc, or aluminum. 2. The thermal transfer sheet according to 1. 5. When the heat-resistant particles are an organic filler or an inorganic filler and the thickness of the heat-resistant lubricating layer is X, the large particles have a particle size of 0.5X to X, and the small particles have a large particle size. 1 / diameter
2 or less, and the ratio of large particles / small particles is 1/4 to 4
The thermal transfer sheet according to claim 1, wherein the weight ratio is / 1. 6. The heat-resistant lubricating layer has a thickness of 0.1 to 0.5 μm.
The thermal transfer sheet according to claim 1, wherein