JPH0747774A - Heat transfer sheet - Google Patents

Abstract

PURPOSE:To provide a heat transfer sheet in which no peeling of a dye layer occurs at the time of rewinding even if the sheet is wound in a rolled state and an image of high quality can be formed. CONSTITUTION:A heat transfer sheet comprises a dye layer containing dye and binder and formed on a base material film, wherein the layer contains fine particles each having a particle size of 1.0mum or less and fine particles each having a particle size of 5mum or more and heat fusibility.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet, and more particularly, it is useful for a thermal transfer system using a sublimable dye (heat transferable dye) and can be used even in a state of being wound in a small roll.
An object of the present invention is to provide a thermal transfer sheet which has a good stability of a dye layer and which can form a high quality image.

[0002]

2. Description of the Related Art Inkjet systems, thermal transfer systems, etc. have been developed as a method for simply and rapidly providing an excellent monocolor or full-color image in place of conventional general printing methods and printing methods. , The so-called sublimation heat transfer method, which uses a sublimable dye, has the best continuous gradation and gives a full-color image comparable to a color photograph. The thermal transfer sheet used in the sublimation type thermal transfer system described above forms a dye layer composed of a sublimable dye and a binder on one surface of a substrate film such as a polyester film, and, on the other hand, in order to prevent the thermal head from sticking. A substrate having a heat-resistant layer provided on the other surface of the substrate film is generally used. The dye layer surface of such a thermal transfer sheet is superposed on an image receiving sheet having a dye receiving layer made of polyester resin or the like, and the dye in the dye layer is transferred to the image receiving sheet by heating imagewise from the back surface of the thermal transfer sheet with a thermal head. Then, a desired image is formed.

[0003]

Problems to be Solved by the Invention The thermal transfer sheet used in the thermal transfer system is usually wound in a roll shape on a winding core such as a paper tube according to the size of the printer. When wound in such a roll shape, the back layer of the thermal transfer sheet and the dye layer are stored for a relatively long time in a state of being in contact with each other, but the back layer and the dye layer are blocked during the storage, particularly Since the winding pressure is large near the winding core, there is a problem that the dye layer is peeled off by the back surface layer when rewound during printing. As a method for solving such a problem, it is possible to add relatively large fine particles to the coating liquid when forming the dye layer,
In this case, the coating suitability of the coating liquid is lowered and a uniform and smooth dye layer is not formed. Further, when these fine particles are high melting point fine particles such as inorganic fine particles, there is a problem that the image formed during image formation is roughened. Therefore, an object of the present invention is to solve the above problems and provide a thermal transfer sheet capable of forming a high-quality image without peeling of the dye layer during rewinding even when the thermal transfer sheet is rolled and stored. That is.

[0004]

The above object can be achieved by the present invention described below. That is, the present invention relates to a thermal transfer sheet comprising a base film and a dye layer comprising a dye and a binder, wherein the dye layer is fine particles having a particle size of 1.0 μm or less and heat melting particles having a particle size of 5 μm or more. It is a thermal transfer sheet characterized by containing and.

[0005]

The dye layer of the thermal transfer sheet contains fine particles having a particle diameter of 1.0 μm or less and heat-meltable fine particles having a particle diameter of 5 μm or more, so that the thermal transfer sheet can be wound in a roll shape and stored. It is possible to provide a thermal transfer sheet capable of forming a high quality image without peeling of the dye layer upon returning.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. The thermal transfer sheet of the present invention,
Basically, as in the prior art, a dye layer is formed on a substrate film via an intermediate layer, if necessary. The substrate film of the thermal transfer sheet of the present invention as described above may be any one as long as it has a conventionally known degree of heat resistance and strength, for example, 0.5 to 50 μm, preferably 3 to 10 μm. Paper having a certain thickness, various processed papers, polyester film, polystyrene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, cellophane, etc. are particularly preferable. These substrate films may be of single-wafer type or continuous film, and are not particularly limited. The dye layer formed on the surface of the base film is a layer in which the dye is carried by an arbitrary binder resin.

As the dyes to be used, any of the dyes used in conventionally known thermal transfer sheets can be effectively used in the present invention. For example, some preferable dyes are, for example, diarylmethane-based dyes and thoria-based dyes. Reel methane series, thiazole series, methine series such as merocyanine,
Indoaniline, acetophenone azomethine, pyrazoloazomethine, imidazole azomethine, imidazoazomethine, azomethine typified by pyridone azomethine, xanthine oxazine, dicyanostyrene, cyanomethylene typified by tricyanostyrene, thiazine, azine System, acridine system, benzeneazo system, pyridone azo, thiophene azo, isothiazole azo, pyrrole azo, pyrazole azo, imidazole azo, thiadiazole azo, triazole azo, disazo and other azo systems,
Dyes of spirodipyran type, indolinospiropyran type, fluorane type, rhodamine lactam type, naphthoquinone type, anthraquinone type, quinophthalone type are representative, and specifically, the following dyes can be preferably used.

C. I. (Color Index) Yellow 51,
3, 54, 79, 60, 23, 7, 141, 201, 2
31; C.I. I. Disperse Blue 24, 56, 14, 30
1, 334, 165, 19, 72, 87, 287, 15
4, 26, 354; C.I. I. Disperse threads 135, 146, 59,
1, 73, 60, 167; C.I. I. Disperse Violet 4, 13, 26, 3
6, 56, 31; C.I. I. Disperse Orange 149; C.I. I. Solvent Yellow 56, 14, 16, 29; C.I. I. Solvent Blue 70, 35, 63, 36, 5
0, 49, 111, 105, 97, 11; C.I. I. Solvent Red 135, 81, 18, 25,
19, 23, 24, 143, 146, 182, C.I. I. Solvent Violet 13; C.I. I. Solvent Black 3; C.I. I. Solvent Green 3 etc.

For example, as cyan dyes, Kayaset Blue 714 (Nippon Kayaku, Solvent Blue 63), Foron Brilliant Blue SR (Sand, Disperse Blue 354), Waxolin AP-FW (ICI)
Manufactured by Solvent Blue 36), as a magenta dye, M
S-REDG (Mitsui Toatsu, Disperse Red 6
0), Macrolex Red Vio Red R (manufactured by Bayer, Disperse Violet 26), and as yellow dyes, Foron Brilliant Yellow S-6GL (manufactured by Sand, Disperse Yellow 231), Macrolex Yellow 6G (manufactured by Bayer, Diel Spurs yellow 2
01) and the like.

As the binder resin for supporting the dye as described above, any conventionally known binder resin can be used, and preferred examples include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose. , Methyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose derivatives such as cellulose nitrate, polyvinyl alcohol,
Polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, polystyrene, polyvinyl chloride, vinyl resins such as polyacrylamide, acrylic resins such as polyacrylonitrile and polyacrylic acid ester, polyamide resins, polyester resins, polycarbonate resins, phenoxy Resin, phenolic resin,
Epoxy resins and the like can be mentioned, and of these, cellulose-based, acetal-based, butyral-based, polyester-based and the like are preferable from the viewpoint of heat resistance, dye transferability and the like. Further, the dye layer may also contain various conventionally known additives as required.

Such a dye layer is preferably prepared by adding the above-mentioned sublimable dye, binder resin, two kinds of fine particles having different particle sizes and other optional components to a suitable solvent to dissolve or disperse each component. A dye layer-forming coating material or ink is prepared, and this is applied and dried on the above-mentioned base material film to be formed. The dye layer thus formed has a thickness of 0.2-5.
The sublimable dye in the dye layer has a thickness of 0 μm, preferably 0.4 to 2.0 μm.
Suitably it is present in an amount of 90% by weight, preferably 10-70% by weight. The dye layer to be formed is formed by selecting one color from the above dyes when the desired image is a mono color image, and when the desired image is a full color image, for example, a suitable cyan, magenta and Yellow (and optionally black) is selected to form yellow, magenta and cyan (and optionally black) dye layers.

The fine particles contained in the dye layer as described above are
It is a mixture of fine particles having a particle diameter of 1.0 μm or less and heat melting particles having a particle diameter of 5 μm or more. These fine particles may be organic or inorganic, but preferred fine particles are wax fine particles that melt at the temperature at the time of thermal transfer, and since these wax fine particles have a wide range of particle size distribution, commercially available wax fine particles have Of commercially available fine particles of 1.0
Fine particles having a particle size of 5 μm or less and fine particles having a particle size of 5 μm or more may be classified and used, for example, using a sieve. The lower limit of the particles having a particle size of 1.0 μm or less is preferably about 0.2 μm. The particle size of 5 μm or more is preferably in the range of about 5 to 15 μm. When the total amount of the fine particles having a particle diameter of 1.0 μm or less and the particle having a particle diameter of 5.0 μm or more is 100 parts by weight, the former is 20 to 80 parts by weight and the latter is 80 to 20 parts by weight. If the range is preferable and the former is too small, the viscosity of the dye layer-forming coating solution becomes too low, and the coating suitability becomes insufficient. On the other hand, if the latter is too small, the blocking prevention property during storage becomes insufficient.

The melting points of both are 90
It is preferable that the wax fine particles melt at a temperature of about 120 ° C., and if the melting point is too low, the antiblocking property is insufficient. On the other hand, if the melting point is a high melting point that does not melt at the temperature during thermal transfer, The transferability of the dye in (3) is hindered and the resulting image is roughened. These fine particles are used in the range of 0.1 to 20% by weight, preferably 0.5 to 10% by weight, in the solid content of the coating liquid forming the dye layer. If the amount used is too small, the effect of the present invention will be insufficient, while if it is too large, the film strength of the dye layer will decrease, and the resulting image density will decrease.

Further, in the present invention, an intermediate layer can be provided between the base film and the dye layer for the purpose of improving adhesiveness, cushioning property and the like. Examples of the material forming the intermediate layer include polyurethane resin, acrylic resin, polyethylene resin, butadiene rubber, and epoxy resin. The thickness of the intermediate layer is preferably about 0.1 to 5 μm. The method for forming the intermediate layer may be the same as that for the dye. The image-receiving sheet used for forming an image using the thermal transfer sheet as described above may be any one as long as its recording surface has a dye-accepting property for the dye, and a dye-accepting property. Without paper, metal, glass,
In the case of synthetic resin or the like, the dye receiving layer may be formed on at least one surface thereof. In particular, when the thermal transfer sheet of the present invention is used, even if the image receiving sheet has a smooth dye receiving layer, the slip property and the peeling property are good.

As the means for applying thermal energy used when performing thermal transfer using the above-mentioned thermal transfer sheet and the above thermal transfer image-receiving sheet, any conventionally known applying means can be used. For example, a thermal printer (for example, By controlling the recording time with a recording device such as a video printer VY-100 manufactured by Hitachi, Ltd., 5
A desired image is formed by applying thermal energy of about 100 mJ / mm ² .

[0016]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the text, parts and% are based on weight unless otherwise specified. Example 1 A 6 μm thick polyethylene terephthalate film having a heat-resistant back surface on which a dye layer was formed as a base film was coated with the following ink composition for forming a dye layer to a dry thickness of 1.0 g / m 2. A thermal transfer sheet of the present invention was prepared by applying gravure printing so as to have a value of ² and drying.

Ink for dye layer : Sublimable dye (Nippon Kayaku, CI Solvent Blue 63) 4.0 parts Polyvinyl butyral resin (S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.) 3.0 parts Polyethylene wax (grains) Diameter 1.0 μm or less, melting point 105 to 112 ° C. 0.1 part Polyethylene wax (particle size 5.0 μm or more, melting point 105 to 112 ° C.) 0.1 part Methyl ethyl ketone / toluene (1/1) 93.0 parts

Example 2 A thermal transfer sheet of the present invention was obtained in the same manner as in Example 1 except that the ink for the dye layer in Example 1 was replaced with the ink having the following composition. Ink for dye layer : Sublimation dye (Nippon Kayaku, CI Solvent Blue 63) 4.0 parts Polyvinyl butyral resin (S-REC BX-1, Sekisui Chemical Co., Ltd.) 3.0 parts Polyethylene wax (particle size 1. 0 μm or less, melting point 105 to 112 ° C.) 0.2 part Polyethylene wax (particle size 5.0 μm or more, melting point 105 to 112 ° C.) 0.1 part Methyl ethyl ketone / toluene (1/1) 93.0 parts

Comparative Example 1 In Example 1, polyethylene wax (particle size 1.0 μ
A thermal transfer sheet was obtained in the same manner as in Example 1 except that only 0.2 part of a resin having a melting point of m or less and a melting point of 105 to 112 ° C) was used. Comparative Example 2 In Example 2, polyethylene wax (particle size 5.0μ
A thermal transfer sheet was obtained in the same manner as in Example 1 except that only 0.2 parts of m or more, melting point 105 to 112 ° C.) was used.

Reference Example 1 Next, synthetic paper YUPO (thickness 150 μm) was used as a substrate,
An image-receiving sheet used in the present invention and comparative examples was coated on one surface with a coating solution for receiving layer having the following composition at a rate of 4.5 g / m ² when dried and dried at 100 ° C. for 30 minutes. Obtained. Receptor layer coating liquid composition : Polyester resin (Toyobo, Vylon 103) 100 parts Amino-modified silicone oil (Shin-Etsu Chemical Co., X-22-343) 0.5 part Epoxy-modified silicone oil (Shin-Etsu Chemical Co., KF- 393) 0.5 part Toluene / methyl ethyl ketone (weight ratio 1/1) 500 parts

Thermal transfer test : The thermal transfer sheets of the above-mentioned Examples and Comparative Examples were wound around a paper tube in a roll shape with a thickness of about 15 mm and left at 40 ° C. for one month. Then, in the printer, the dye layer of the thermal transfer sheet and the receiving layer of the image receiving sheet are faced and overlapped with each other, and the thermal head (KMT-85-6, MPD2) is placed on the back surface of the thermal transfer sheet.
Head applied voltage 12.0V, applied pulse width 1
6.0 msec. / Line to 1 msec. Step pattern that decreases sequentially every time, 6 line /
Thermal head recording was performed under the condition of mm (33.3 msec./line), and the results shown in Table 1 below were obtained.

[0022]

[Table 1] Evaluation method : Blocking : The presence or absence of peeling noise between the dye layer and the back layer during rewinding was observed. Uneven printing : The printed part (especially the highlight part) after printing was observed.

[0023]

[Effects] According to the present invention as described above, the dye layer of the thermal transfer sheet contains fine particles having a particle diameter of 1.0 μm or less and heat-meltable fine particles having a particle diameter of 5 μm or more, so that the thermal transfer sheet is roll-shaped. It is possible to provide a thermal transfer sheet capable of forming a high-quality image without peeling of the dye layer upon rewinding even when wound and stored.

Claims (2)

[Claims] 1. A thermal transfer sheet comprising a substrate film and a dye layer comprising a dye and a binder provided on the substrate film, wherein the dye layer comprises fine particles having a particle size of 1.0 μm or less and heat-meltable particles having a particle size of 5 μm or more. A thermal transfer sheet comprising: 2. The content of fine particles in the dye layer is from 0.1 to 20.
The thermal transfer sheet according to claim 1, which occupies weight%.