JPH0358887A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To form an image enhanced in abrasion resistance on a transparent plastic film by successively laminating a specific heat-meltable release layer, a colored ink layer and a heat-meltable adhesive layer to the surface of a polyester film having a heat-resistant layer provided to the rear thereof. CONSTITUTION:A heat-meltable release layer based on wax and a colored ink layer based on a thermoplastic resin and an oil-soluble dye or disperse dye low in heat sublimability are successively laminated to the surface of a polyester film having a heat-resistant layer provided to the rear thereof. Further, a heat-meltable adhesive layer based on a thermoplastic resin is laminated to the aforementioned colored ink layer to obtain a thermal transfer recording medium. As the wax of the heat-meltable release layer, paraffin wax having an m.p. of about 50 - 100 deg.C is suitable. As the thermoplastic resin of the heat- meltable adhesive layer, a polyamide resin having a heat softening point of about 100 - 140 deg.C is optimum from the respect of the reproduction of a dot at the time of the formation of an image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a thermal transfer method for forming monochrome, multicolor, or other images on a sheet by a thermal transfer method using a heat supply member such as a thermal head. Regarding recording media, especially OHP
This invention relates to a recording medium that is optimal for recording on transparent plastic sheets for (overhead projectors).

[Conventional Technology In color printing for co-word processors and computer graphics, color ink ribbons are attached to printers (in this specification,
(The term transfer recording medium is used as a general term for a medium that supplies an image forming element such as an ink ribbon). An example of a conventional heat-sensitive transfer recording medium of this type is published in Tokuban Sho 81-2739.
89 or Japanese Patent Laid-Open No. 64-27992.

The medium structure disclosed in JP-A No. 81-273989 has a wax release layer/colored ink layer/wax adhesive layer laminated in this order on a U body.

The medium structure disclosed in Japanese Patent Laid-Open No. 04-27992 and the like has a wax release layer/colored ink layer/resin adhesive layer laminated in this order on a substrate.

[Problems to be Solved by the Invention] With both of the above structures, when an image is printed on a transparent plastic sheet for OHP (generally made of polyester film) using these media, When projected, a problem arises in that the colors of the image (yellow, red, indigo, etc.) become opaque and dark. This is due to the fact that both of the above structures use pigments in the colored ink layers.

The former structure also has the problem of poor adhesion to the OHP transparent plastic sheet and poor abrasion resistance. This is because the adhesive layer is made of hot-melt wax.

The present invention has been made in order to solve the above-mentioned conventional technology, and an object thereof is to provide a thermal transfer recording medium that can obtain transparent colors even when an image is formed on a transparent OHP sheet. shall be.

Another object of the present invention is to improve the abrasion resistance of images formed on transparent plastic sheets for OHP.

[Means for Solving the Problems] In order to achieve the above object, the heat-sensitive transfer recording medium of the present invention has a heat-melting release layer mainly composed of wax on the surface of a polyester film provided with a heat-resistant layer on the back surface. , a colored ink layer containing a thermoplastic resin and a dye as its main components, and a heat-melting adhesive layer containing a thermoplastic resin as its main components are laminated in this order. The dye in the colored ink layer is an oil-soluble dye or a disperse dye with low thermal sublimability.

The wax for the heat-melting release layer has a melting point of approximately 50°.
C-1.00°C paraffin wax, microcrystalline wax, rice wax, etc. can be used.

The thickness of the hot melt release layer is preferably about 0.5 μm to 2 μm.

As the coloring agent for the colored ink layer, an oil-soluble dye or a disperse dye that is decomposed to develop color in an organic solvent such as toluene or methyl ethyl ketone is used. Furthermore, a dye with low thermal sublimation property is selected in consideration of the physical properties after image formation, that is, after transfer. The colored ink layer also contains an adhesive. As this binder, thermoplastic resins such as ethylene vinyl acetate copolymer, acrylic resin, styrene acrylic resin, styrene rubber, styrene butadiene rubber, and epoxy resin are used. The thickness of the colored ink layer is approximately 0.5μm-2μ
m is desirable.

As the thermoplastic resin for the hot melt adhesive layer, ethylene vinyl acetate copolymer, polyester copolymer, polyacrylic resin, polyamide resin, etc. can be used. In particular, it has been found that a polyamide resin having a thermal softening point of about 100 DEG C. to 140 DEG C. is optimal from the viewpoints of dot reproducibility in certain image shapes, adhesion to OHP sheets, and the like. The thickness of the hot melt adhesive layer is preferably about 0.5 μm to 2 μm.

[Example] Example 5: A liquid of the following formulation A was applied to the back side of a 7 μm thick biaxially stretched polyester film (Lumirror (trademark), Toray Industries, Inc.) by gravure coating (2() μm plate deep). evening edition) and
A heat-resistant slipping layer with a thickness of 0.1 μm was provided. Next, the surface of the above film was gravure coated (30 μm deep plate) with a hot melt male release agent having the following formulation B to provide a release layer with a thickness of 1 μm. A blue ink of the following formulation C was gravure coated (30 μm deep plate) on top of it to form an ink layer with a thickness of 1 μm. Furthermore, a hot-melt adhesive of the following formulation D was gravure coated (30 μm deep plate) to a thickness of 1i.
t m adhesive layer was provided, and the thermal transfer recording medium according to the present invention was fully utilized.

Formulation A, heat-resistant lubricant TRL-20C Matsumoto Yushi Co., Ltd. 1 part by weight methanol
・50 parts by weight water
49 parts by weight Recipe B1 Hot-melt release agent rice spawn wax 2 parts QiQ (Nippon Sekiro Co., Ltd.) Toluene 40 parts by weight Isobrobyl alcohol 4 Stirred in a DltQ8B mixer for 2 hours Recipe C, indigo ink disperse dye, PT87B Bfff parts ( Mitsubishi Kasei Co., Ltd.) Ethylene-vinyl acetate copolymer 5 parts by weight (Seikadyne 700B, Dainichiseika Co., Ltd.) Toluene
50 parts by weight Ethyl acetate 42 parts by weight Stir in a mixer for 2.5 hours Recipe D, hot-melt adhesive polyamide loff parts (Tomide 11394, Fuji Kasei Kogyo Co., Ltd.) Isobrobyl alcohol 40 parts by weight Toluene
Comparative Example Stirred in a 50 parts by weight mixer for 2 hours In order to compare the image formation state with the above-mentioned Example according to the present invention,
In place of the blue ink of the above prescription C, blue ink of the following formulation E was used, and in place of the hot melt adhesive of the above prescription D, a hot melt adhesive of the following formulation E was used to create a comparative impression. A thermal transfer recording medium was created.

Prescription ES blue ink pigment, phthalocyanine blue (Toyo Ink (flavor)) Ethylene-vinyl acetate copolymer (Seikadyne 700B, Dainichiseika toluene ethyl acetate mixer, stirred between 3 It. SO) Recipe F1 Hot-melt adhesive Ricepawn Wax (Nippon Sekiro Co., Ltd.) Toluene Isobrobyl alcohol Ethyl acetate Ethylene vinyl acetate copolymer (Seikadyne 700B, stirred for 2 hours in a Dainichi 16ka mixer 3 parts by weight 5 parts by weight Co., Ltd.) 50 parts by weight 42 Market Department 20 iIf Melon Department 30 Heavy Melon Department 19 Weight Parts 30 Heavy Tray Department 1 Weight Part Co., Ltd.) Each of the ink ribbons according to the above Examples and Comparative Examples was set in a NEC (l2) word processor Bungo Mini 7GX. A blue transfer image was formed on a transparent polyester film for OHP (Lumirror (trademark), Toray Industries, Inc.) having a thickness of 100 μm. Then, each of the above films (OHP sheets) was projected using an OHP projector S1 manufactured by Fuji Xerox Co., Ltd., and the above two examples were compared. As a result, the examples according to the present invention are superior in all aspects of desired color reproducibility, transparency, and sharpness. -1f light.

In addition, each of the above films (OH
P sheet) was tested with a Gakushin friction tester under a load of too much.
The degree of contamination of certain cotton cloths was compared under the condition of 20 frictions. As a result, the gray scale judgment grade (5-level display, the higher the grade, the better) improved from grade 2 to grade 4, and the FII abrasion resistance of the image formed in the example of this invention improved. There was found.

[Effects of the Invention] According to the thermal transfer recording medium of the present invention, even when an image is displayed on a transparent plastic sheet for OHP, a transparent colored image can be obtained, and the abrasion resistance of the image is improved. will also be good.

Claims (2)

[Claims] (1) On the surface of a polyester film with a heat-resistant layer on the back side, a heat-melting peeling layer mainly composed of wax, and a colored ink mainly composed of a thermoplastic resin and an oil-soluble dye or disperse dye with low heat sublimation property. 1. A heat-sensitive transfer recording medium characterized by sequentially laminating a layer and a heat-melting adhesive layer containing a thermoplastic resin as a main component. (2) Claim (2) wherein the thermoplastic resin of the heat-melting adhesive layer is a polyamide resin having a heat softening point of about 100°C to 140°C.
1) The thermal transfer recording medium described above.