JPS6389383A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To enhance the friction resistance and uniformity of a transfer image, by providing a transfer layer, which consists of a particulate coloring material, particulate wax and a water-soluble resin respectively having melting or softening points received in a specific temp. range on a support. CONSTITUTION:A transfer layer consisting of a coloring material based on a dye and/or pigment and a thermoplastic resin having a melting or softening point of 70-140 deg.C, wax having a melting or softening point of 70-130 deg.C and a water-soluble resin is provided on a support. The coloring material and wax are present in the transfer layer in a particulate form. The coloring material used in the above-mentioned transfer layer is formed by kneading the dye and/or pigment and the thermoplastic resin under heating and grinding the resulting mixture into a fine particulate form. As the dye and pigment, the inorg and org. dyes and pigments used in printing ink and paint can be used. As the thermoplastic resin, there is an acrylic resin. As the wax, carnauba wax, polyethylene wax or the like are used. The coloring material and wax are used in a fine particulate form and the average particle size thereof in the transfer layer is pref. about 0.1-5mum. The use ratio of the coloring material particle, the wax particle and the water-soluble resin is 1pt.wt., about 0.2-1pt.wt. and 0.05-0.2pt.wt. respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a thermal transfer recording medium for performing thermal transfer recording on recording paper by utilizing the heat-melting properties of an ink layer.
It can also be applied to printers such as computers and word processors, and barcode printers.

[Prior Art] A thermal transfer medium is known in which a transfer layer consisting of a heat-fusible substance such as paraffin wax and a coloring agent such as a dye or pigment is provided on a support, but paraffin waxes have poor mechanical strength. This has the disadvantage that the abrasion resistance of the transferred image is poor due to the weak resistance.

In order to improve this drawback, methods have been taken such as adding thermoplastic resin or making the transfer layer as thin as possible.
The former has the problem that when the resin component increases, the adhesive strength becomes stronger, making it difficult to transfer, and the thermal sensitivity deteriorates, while the latter has the problem of worsening the uniformity of the transferred image and lowering the image density. Ta.

[Structure] The structure of the present invention for achieving the above object includes a coloring material mainly composed of a dye and/or a pigment, a thermoplastic resin having a melting point or softening point in the range of 70 to 140°C, and Alternatively, in a thermal transfer recording medium in which a transfer layer containing a wax having a softening point in the range of 70 to 130°C and a water-soluble resin is provided on a support, the coloring material and wax are present in the form of particles in the transfer layer. This is a thermal transfer recording medium characterized by the following.

The transfer layer of the thermal transfer recording medium of the present invention is overlapped with a recording paper, and a desired image is formed on the recording paper by thermal printing from the back side of the thermal transfer recording medium. As the support for the thermal transfer recording medium in the present invention, various conventionally known supports can be used as appropriate.

Examples of these include plastic films such as polyester film, polyamide film, polyvinyl chloride film, polyethylene film, polypropylene film, polyimide film, borizulfon film, and polycarbonate film, and condenser paper.

The coloring material used in the transfer layer of the present invention is obtained by heating and kneading a conventionally known dye and/or pigment and a thermoplastic resin having a melting point or softening point of 70 to 140° C., and then pulverizing the mixture into fine particles. As dyes and pigments, inorganic dyes and pigments used in printing inks, paints, etc. can be used.

Specific examples include carbon black, Disazo Yellow, Brilliant Carmine 6B, Lake Red C1 Phthalocyanine Blue, Kayaset Black KR (Nippon Herbal Medicine), Oil Yellow 3G (Orient Chemical), Chikara A7 Settretsudo ni-BE (Japanese Herbal Medicine), and Kayaset Blue. -KFL
(Japanese Herbal Medicine) etc.

As a thermoplastic resin, the melting point or softening point is 70 to 140°C.
Various resins can be used. Examples include acrylic resin, methacrylic resin, styrene resin, vinyl acetate resin, vinyl chloride resin, nylidene chloride resin, petroleum resin, novolak resin, olefin resin, polyester resin, polyacetal resin, or copolymers thereof.

If the melting point or softening point is lower than 70°C, the abrasion resistance of the transferred image in a high-temperature environment (50 to 60°C) will deteriorate;
If the temperature is higher than 40° C., high energy is required during thermal transfer recording, causing problems such as slow recording speed and shortened thermal head life.

Dyes and/or pigments and melting point or softening point 70-140℃
The proportion of the thermoplastic resin used is preferably about 5 to 100 parts by weight per 1 part by weight of the dye and/or pigment.

The wax used in the present invention has a melting point or softening point of 70 to 1
Wax at 30° C. is used in particulate form. It is preferable that the penetration rate (at 25°C) is 1 or less.

If the melting point or softening point of this wax is lower than 70° C., the applied thermal energy is consumed to melt the wax, resulting in insufficient energy to soften the resin particles. Therefore, only the wax is preferentially transferred, and the transfer of the transfer layer becomes insufficient, causing blurring of the transferred image and deterioration of sharpness. Further, if the temperature is higher than 130° C., high thermal energy is required for transfer.

Specific examples of waxes that satisfy the above conditions include carnauba wax, polyethylene wax, Fischer-Tropsch wax, montan wax derivatives, and hydrogenated castor oil.

The coloring material and wax used in the present invention are used in the form of fine particles, and the average particle size in the transfer layer is 0.1 to 5 μm.
The smaller the degree, the better the thermal sensitivity and resolution will be. However, if it is too small, the abrasion resistance will be poor, and if it is too large, the thermal sensitivity and resolution will be poor.

The transfer layer also contains a water-soluble resin as a binder, and specific examples of these water-soluble resins include polyvinyl alcohol, methoxycellulose, hydroxyethylcellulose, carboxylmethylcellulose, polyvinylpyrrolidone, polyacrylamide, starch,
There are gelatin, etc.

The ratio of these colored material particles, wax particles, and water-soluble resin used is 0.00 parts by weight of wax particles to 1 part by weight of colored material particles.
2-1@Φ parts, water-soluble resin 0,05-0.2 parts.

If there are too few wax particles, a uniform image cannot be obtained, and if there are too many, the abrasion resistance will deteriorate. Furthermore, if the amount of the water-soluble resin is too low, it will not be effective as a binder and will cause scumming, and if it is too large, it will be difficult to transfer and a clear image will not be obtained. or,
If the coloring material and wax are not in the form of particles but in the form of a film, the boundary between the transferred area and the non-transferred area will not be sharp during transfer, resulting in a decrease in resolution.

As the recording paper used with the thermal transfer recording medium of the present invention, plain paper, synthetic paper, plastic film, etc. can be used as appropriate.

The thermal transfer recording medium of the present invention is prepared by mixing the above-mentioned transfer layer forming components with water, and applying the mixture onto a support in a total solid content of 1 to 1.
It can be produced by coating the resin at a density of 10 g/m2 and drying at a temperature below the melting point or softening point of the resin or wax particles so as not to fuse the resin and wax particles.

[Example] Next, the present invention will be roughly described in detail with reference to Examples. It should be noted that all of the dimensions of each component described in the Examples, ie, "parts" and "%", are based on weight.

Preparation of Colored Materials Each of the above compositions A to C was heated and kneaded in a roll mill, cooled, and pulverized in a jet mill to produce a fine-particle coloring material having an average particle size of 3 μm.

Preparation of wax dispersion: Mixtures of each of the following compositions (1) to (L) were prepared.

Examples 1 to 5 The above compositions were mixed uniformly with a stirrer and applied.
The liquid was adjusted. The coating liquid was applied onto a 6 μm thick polyester film using a wire bar so that the amount of adhesion after drying was 49/m2, and the film was dried with warm air (50°C) to obtain a thermal transfer recording medium of the present invention. .

Comparative Example 1.2 A fine particle coloring material having an average particle size of 3 μm was prepared using the same composition as in the example.

A thermal transfer recording medium of Comparative Example 1.2 was prepared in the same manner as in the Example except that the colored material was used in place of A of Example 1.

Comparative Example 3 A composition consisting of 10 parts of coloring material (A) and 5 parts of paraffin wax (mp 58°C) was stirred well at 60°C in a 77O wet state, and a liquid in which the coloring material (A>) was uniformly dispersed was prepared. Adjust and coat on a 6 μm thick polyester film using a hot melt coater.
A thermal transfer recording medium of Comparative Example 3 was prepared with a good adhesion of ff14(]/m2).

Comparative Example 4 A thermal transfer recording medium of Comparative Example 4 was prepared in the same manner as in Example 1 except that the drying temperature was changed to 100°C.

The transfer layer of the thermal transfer recording medium prepared as described above was brought into close contact with the surface of high-quality paper, and printing was performed using a thermal transfer printer by applying an energy of 0.7 mJ/dat.

In order to examine the abrasion resistance of the printed image, the abrasion resistance against cardboard was tested using a Love Tester (manufactured by Toyo Seiki) (air temperature: 20° C., 150° C.). The results were as follows.

Image density: Anti-fAm degree of solid print area (Macbeth reflection densitometer) Uniformity Presence or absence of voids (areas where ink is not transferred) in double-peta print area: No voids Rub resistant Nirabuchistar (manufactured by Toyo Seiki) > friction against cardboard using 100 reciprocating loads 10og, m2 Good...No change Bad...A lot of ink is removed from the printed area and a lot of ink is deposited on the non-printed area.Resolution Two-sided line area The border between the non-printing area and the non-printing area is well-defined...the border is clear and sharp.

Evil...The boundaries are unclear and unclear. Must have.

[Effects] As explained above, by using the thermal transfer recording medium of the present invention, images with high density, uniformity, and resolution can be obtained.
A transferred image with excellent abrasion resistance can be obtained.

Claims (1)

[Claims] Dyes and/or pigments with a melting point or softening point of 70-1
A transfer layer comprising a coloring material whose main component is a thermoplastic resin having a temperature of 40°C, a wax having a melting point or softening point of 70 to 130°C, and a water-soluble resin is provided on a support. A thermal transfer recording medium characterized in that the coloring material and wax are present in the transfer layer in the form of particles.