JPH02589A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To print and record on a transfer sheet having rough surface in high quality by incorporating as a main ingredient unvulcanized rubber or unvulcanized rubber and organic lubricant in a peeling layer. CONSTITUTION:A peeling layer 2 is formed to contain as a main ingredient or ingredients unvulcanized rubber 4 or unvulcanized rubber 4 and organic lubricant 5. The rubber used for the layer preferably includes polyisoprene, polybutadiene, ethylenepropylene rubber, butyl rubber and nitrile rubber. These preferable rubbers have 60-200 deg.C of a melting point. The lubricant preferably includes waxes, particularly carnauba wax, montan wax and high density polyethylene; higher fatty acid and its derivative. If the layer is of (unvulcanized rubber + organic lubricant), the ratio of the rubber/lubricant is normally ranged at 5-95/95-5 (by weight) and preferably 30-70/70-30 (by weight).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer recording medium for printing and recording on transfer paper by thermal transfer using the heat-melting properties of an ink layer, and is applicable to printers such as computer word processors and barcode printers. It can also be applied to

In recent years, transfer-type thermal recording methods have become popular as a simple plain paper recording method. In this method, transfer paper is placed on the ink layer surface of a thermal transfer recording medium (a so-called ink ribbon, basically a support with a heat-melting ink layer provided), and a thermal head is applied from the recording medium side. Printing is performed by melting and transferring an ink layer onto a transfer paper.

Thermal transfer recording media used in this method include those in which a heat-melting ink layer containing a colorant and a wax as an organic lubricant and/or a low-melting point resin as a binder is provided on a support; A typical example is one in which a release layer containing wax as a main component is provided between the ink layer and the ink layer. In particular, the latter recording medium is useful because it provides a peeled Ni layer to smooth the transfer of the melted ink layer during transfer. However, with conventional recording media, whether with or without a release layer, the print quality is easily affected by the surface smoothness of the transfer paper, and especially when it comes to transfer paper with low surface smoothness such as bond paper, high quality Printing records was difficult.

Conventionally, in order to improve such defects, heat treatment is performed after printing (Japanese Patent Application Laid-open No. 76276/1983), and magnetic force (
JP-A No. 52-96549) and electrostatic force (JP-A No. 55-Sho.
65590) or by adding an oily substance to the ink layer to reduce the melt viscosity during transfer (Japanese Patent Application Laid-Open No. 60-25762).

Measures have been proposed, such as adding a thermally decomposable substance (Japanese Unexamined Patent Publication No. 60-82389) or a thermally expandable substance (Japanese Unexamined Patent Publication No. 60-25762) to thermally sensitize the film.

In addition, a technology has been previously proposed that attempts to improve print quality by creating multiple layers of heat-melt ink, in which heat-melt inks with slightly different melting points are layered, and pigments are added to one or both of them. Add (Japanese Patent Application Laid-Open No. 59-224392
Techniques have been proposed, such as providing a layer made of a heat-fusible substance containing no colorant on a heat-fusible ink layer (Japanese Patent Laid-Open No. 60-97888).

However, with this method of recording by transferring melted ink that has become a liquid, it is possible to obtain inferior print quality on transfer paper with low surface smoothness compared to transfer paper with high surface smoothness. Therefore, it was not possible to fundamentally solve the drawback of transfer-type thermal recording that the print quality depends on the smoothness of the surface of the transfer paper.

On the other hand, when heat energy is applied, the surface of the transfer paper has a low surface smoothness due to the ink mainly composed of a resin that exhibits stickiness but does not melt into a low-viscosity liquid and has a certain degree of mechanical strength. By using ink that adheres to the convex parts and covers the concave parts, high-quality printing can be performed on transfer paper with a rough surface like this.

However, such resin inks require more energy to print than conventional wax inks, so it is necessary to use a support film with particularly high heat resistance, and it also reduces the lifespan of the thermal head and heat storage. This is not desirable as it causes problems.

The first object of the present invention is to provide a thermal transfer recording medium that is capable of high-quality print recording not only on transfer paper with a smooth surface but also on transfer paper with a rough surface.

(2)-1 The thermal transfer recording medium of the present invention is of the following three types as shown in FIGS. 1 to 3.

(1) In a thermal transfer recording medium in which a release layer 2 is provided on a support 1 and a hot-melt ink M3 is provided thereon, the release layer 2
A thermal transfer recording medium (FIG. 1) characterized in that the main component is unvulcanized rubber 4.

(2) In a thermal transfer recording medium in which a release layer 2 is provided on a support 1 and a heat-melting ink F33 is provided thereon, the release layer 2 contains unvulcanized rubber 4 and an organic lubricant 5 as main components. A thermal transfer recording medium (Fig. 2) characterized by:

(3) In a thermal transfer recording medium in which a release layer 2 is provided on a support 1 and a heat-melt ink layer 3 is provided thereon, the release layer 2
are the first release layer 2-1 and the second release layer M2 in order from the support side.
-2, and the first and second release layers 2 are laminated in the order of
-1゜2-2 is a) organic lubricant 5, or b) unwashed rubber 4
and an organic lubricant 5 [if the first release layer has a) as the main component, the second release layer has b) as the main component, and conversely, the first release layer has b) as the main component. When used as a component,
Peeling RF3 contains a) as a component. A thermal transfer recording medium characterized by the following [Fig. 3 (A), (B)].

As described above, the basic structure of the thermal transfer recording medium of the present invention is such that the release layer contains unvulcanized rubber as a main component, but in the case of this recording medium (1), there is a problem in the abrasion resistance of the transferred image. However, if an organic lubricant is added to the unvulcanized rubber release layer as in the thermal transfer recording medium (2), it is possible to improve the friction resistance by improving the slipperiness.
), the abrasion resistance can be further improved by forming the release layer into a laminated structure of an organic lubricant-based release layer and an unvulcanized rubber+organic lubricant-based release layer.

Examples of unvulcanized rubber used in the release layer of the present invention include polyisoprene, polybutadiene, styrene-butadiene rubber,
Nitrile rubber, ethylene propylene rubber, butyl rubber,
silicone rubber.

Examples include fluorine rubber and urethane rubber, preferably polyisoprene, polybutadiene, ethylene propylene rubber, butyl rubber, and nitrile rubber. Note that these preferable rubbers have a melting point of 60°C to 200°C.

In addition, organic lubricants include waxes such as natural waxes such as carnauba wax, candelilla wax, beeswax, wood wax, montan wax, spermaceti wax, synthetic waxes such as paraffin wax, microcrystalline wax, oxidized wax, and polyethylene wax; and margarine. Higher fatty acids and their derivatives and metal salts such as acid, lauric acid, mystyric acid, palmitic acid, stearic acid, fromenic acid, and behenic acid; Higher alcohols such as stearyl alcohol and behenyl alcohol; Esters such as fatty acid esters of sorbitan; stearinamide , amides such as oleinamide, and the like. Among them, waxes, particularly carnauba wax, montan wax, and high-density polyethylene; higher fatty acids and derivatives thereof are preferred.

If the release layer is unvulcanized rubber + organic lubricant, unvulcanized rubber/
The organic lubricant ratio usually ranges from 5 to 95/95 to 5 (by weight), preferably from 30 to 70/70 to 30 (by weight). If the lubricant content is less than 5%, the transferred image will become less slippery and no improvement in abrasion resistance will be achieved.

If it exceeds 95%, the image quality will deteriorate, especially on transfer paper with a rough surface.

The thickness of the release layer is usually in the range of 0.2 to 5 μm, preferably 1 to 4 μI in the case of the recording medium of (1) and (2), and the thickness of the first release layer is in the range of the recording medium of (3). Usually 0.1 to 2 μm, preferably 0.5 to 1.5 μm,
The second release layer is 0.2 to 3 μm, preferably 0.2 to 3 μm.
It is in the range of 5 to 2 μm.

Both release layers can be formed by coating with a conventional organic solvent solution (solvents include toluene, methyl ethyl ketone, ethyl acetate, etc.) or dispersion (aqueous may be used in the case of a dispersion), or by hot melt coating without using a solvent.

Next, the heat-melting ink layer will be explained.

This heat-melting ink layer is made of colorant as before.

Composed mainly of organic lubricant and low melting point resin.

The colorant is appropriately selected from conventionally known dyes and pigments. Specific examples of the organic lubricant are as described above.

Low melting point resins include polyamide, polyester, polyurethane, vinyl chloride, cellulose, petroleum,
In addition to styrene-based, butyral-based, and phenol-based resins, examples include ethylene-vinyl acetate copolymers and ethylene-acrylic resins. The ratio of each of these components is colorant/organic lubricant/resin=5-50/30-9015-50
(weight) is appropriate. The heat-melt ink layer can be formed by coating with an organic solvent solution or aqueous dispersion, or by hot-melt coating, as in the case of the release layer. The thickness of the ink layer is usually 0.5 to 5 μm, preferably 1 to 3 μm.

In addition to the above-mentioned components, the release layer and ink layer also contain plasticizers such as fatty acid esters, glycol esters, phosphate esters, and epoxidized linseed oil.

Use a small amount (30% or less) of oily substances such as mineral oil, animal oil, vegetable oil, liquid paraffin, and silicone oil as a softener.
Can be added. Further, in the case of a release layer, a colorant can be added in a small amount.

As the support for supporting the above-mentioned release layer and ink layer, heat-resistant plastic films such as polyester, polycarbonate, triacetylcellulose, polyamide, polyimide, cellophane, parchment paper, condenser paper, etc. can be used, and if necessary, Silicone resin and fluororesin are applied to one side of these supports (the side in contact with the thermal head).

A heat-resistant layer of polyimide resin, epoxy resin, phenol resin, melamine resin, cellulose resin, etc. may be provided.

The present invention will be explained below by way of examples. Note that all parts are parts by weight.

Example 1 A solution consisting of 5 parts of unvulcanized ethylene propylene rubber and 95 parts of methyl ethyl ketone (MEK) was coated on one side of a 3.51-thick polyester film support with a wire bar and dried to form a 1-μm-thick release layer.

Carbon black 3 parts Candelilla wax 10.5 parts Ethylene-vinyl acetate copolymer 1.1 parts Toluene
85 parts were dispersed in a ball mill for 12 hours, applied on the peeled layer in the same manner, and dried to form a 2.5 μm thick hot-melt ink layer. After that, silicone resin was applied to the support side using a smoothing bar. A thermal transfer recording medium of the type shown in FIG. 1 was prepared by coating to form a heat-resistant layer having a thickness of 0.1 part m.

Example 2 Thermal transfer recording of the type shown in Fig. 1 was made in the same manner as in Example 1, except that the rubber component in the release layer forming liquid was changed to unvulcanized polyisoprene rubber, and the thickness of the release layer was set to 0.5 μm. Created media.

Example 3 Example 1 except that the formulation of the release layer forming liquid was changed as follows.
A thermal transfer recording medium of the type shown in FIG. 1 was prepared in the same manner as described above.

10% toluene solution of unvulcanized butyl rubber 99 parts Carbon black 1 part (The above was dispersed in a ball mill for 12 hours) Example 4 Example 1 except that the formulation of the release layer forming liquid was changed as shown below.
A thermal transfer recording medium of the type shown in FIG. 1 was prepared in the same manner as described above.

1 part of carbon black (dispersed in a ball mill for 12 hours) Example 5 Example 2 except that the formulation of the release layer forming liquid was changed as follows.
A thermal transfer recording medium of the type shown in FIG. 1 was prepared in the same manner as described above.

Unvulcanized nitrile rubber 5 parts toluene
95 parts Comparative Example 1 A thermal transfer recording medium was prepared in the same manner as in Example 1 except that a release layer was not provided.

Comparative Example 2 A thermal transfer recording medium was prepared in the same manner as in Example 1, except that the release layer was formed by hot melt coating of paraffin.

Example 6 A thermal transfer recording medium of the type shown in FIG. 2 was prepared in the same manner as in Example 1, except that the formulations of the release layer forming liquid and the ink layer forming liquid were changed as follows.

Release layer forming liquid: Unvulcanized ethylene propylene rubber 7 parts Carnauba wax 3 parts M E K
90 parts (disperse the above in a ball mill for 12 hours) Ink layer forming liquid: Carbon black 3 parts Carnauba wax 10.5 parts Ethylene-vinyl acetate copolymer 1.5 parts Toluene
85 parts Example 7 Example 2 except that the formulation of the release layer forming liquid was changed as follows.
A thermal transfer recording medium of the type shown in Fig. 2 was prepared in the same manner as in .

Unvulcanized polyisoprene rubber 7 parts carnauba wax 3 parts toluene
90 parts Example 8 Example 1 except that the formulation of the release layer forming liquid was changed as follows.
A thermal transfer recording medium of the type shown in Fig. 2 was prepared in the same manner as in .

Amino resin modified montan wax 5 parts toluene
° 45 parts (the above was dispersed in a ball mill for 12 hours) Example 9 Example 1 except that the formulation of the release layer forming liquid was changed as follows.
A thermal transfer recording medium of the type shown in Fig. 2 was prepared in the same manner as in .

Unvulcanized nitrile rubber 3 parts zinc stearate 7 parts toluene
90 parts Example 10 Ethylene propylene rubber 8 parts Carnauba wax 2 parts MEK
90 parts were dispersed in a ball mill for 12 hours,
This was applied onto one side of the same polyester film support as in Example 1 using a wire bar, and dried to form a 0.5 μm thick M-th layer. Next, carnauba wax 10 parts toluene
90 parts were dispersed in a ball mill for 12 hours, applied on the first release layer in the same manner, and dried to form a 1 μm thick second release layer.

After forming a heat-melting ink layer on the second release layer in the same manner as in Example 1, a heat-resistant layer was provided on the support side to produce a thermal transfer recording medium of the type shown in FIG. 3(A). .

Example 11 A thermal transfer recording medium of the type shown in FIG. 3(A) was prepared in the same manner as in Example 1O, except that carnauba wax in the first release layer was replaced with montan wax.

Example 12 First release layer forming liquid: unvulcanized polyisoprene rubber 5 parts carnauba wax 5 parts toluene
A first release layer with a thickness of 1 μm was formed using 90 parts of high density polyethylene wax and 10 parts of toluene as a second release layer forming liquid.
1.5 μm using 90 parts
A thermal transfer recording medium of the type shown in FIG. 3(A) was prepared in the same manner as in Example 10 except that a thick second release layer was formed.

Example 13 A thermal transfer recording medium of the type shown in FIG. 3(A) was prepared in the same manner as in Example 12 except that carnauba wax in the first release layer was replaced with montan wax.

Comparative Example 3 A thermal transfer recording medium was produced in the same manner as in Example 10 except that the first transfer layer was not formed.

Example 14 Carnauba wax 10 parts toluene as first release layer forming liquid
90 parts of unvulcanized polyisoprene rubber, 7 parts of carnauba wax, and 3 parts of toluene were used as a second release layer forming liquid to form a first release layer with a thickness of 1 μm.
A thermal transfer recording medium of the type shown in FIG. 3(B) was prepared in the same manner as in Example 10, except that a second release layer having a thickness of 0.5 μm was formed using 90 parts.

Example 15 A thermal transfer recording medium of the type shown in FIG. 3(B) was prepared in the same manner as in Example 14 except that carnauba wax in the second release layer was replaced with montan wax.

Example 16 A thermal transfer recording medium of the type shown in FIG. 3(B) was prepared in the same manner as in Example 14 except that carnauba wax in the first release layer was replaced with polyethylene wax.

Example 17 The same procedure as in Example 14 was carried out, except that the carnauba wax in the first release layer was changed to polyethylene wax, and the carnauba wax in the second release layer was changed to montan wax.
) type of thermal transfer recording medium was created.

The transfer layer surface of the thermal transfer recording medium prepared as described above was brought into close contact with high-smoothness high-quality paper and low-smoothness bond paper, respectively, and printing was performed using a thermal transfer printer by applying an energy of 0.5 mj/dat. The printed image was evaluated, and the abrasion resistance (room temperature: 20.50°C) of the sample surface was also tested.

The results were as shown in Table 1 below.

(Margin below) Since the thermal transfer recording medium of the present invention uses unvulcanized rubber for the release layer, sufficient image density can be obtained without missing dots even on transfer paper with a rough surface, and When an organic lubricant is used in the release layer, a transferred image with excellent abrasion resistance can be obtained.

[Brief explanation of the drawing]

1 to 3 are schematic views of an example of the thermal transfer recording medium of the present invention. 1...Support 2...Peeling layer 2-1...First peeling 1iF1 layer 2-2...Second peeling layer 3...Thermofusible ink layer

Claims (1)

[Claims] 1. A thermal transfer recording medium in which a release layer is provided on a support and a heat-melt ink layer is provided thereon, characterized in that the release layer is mainly composed of unvulcanized rubber. Thermal transfer recording medium. 2. A thermal transfer recording medium in which a release layer is provided on a support and a heat-melt ink layer is provided thereon, wherein the release layer contains unvulcanized rubber and an organic lubricant as main components. . 3. In a thermal transfer recording medium in which a release layer is provided on a support and a hot-melt ink layer is provided thereon, the release layer is laminated in the order of a first release layer and a second release layer from the support side, A thermal transfer recording medium, wherein the first and second release layers contain either a) an organic lubricant, or b) an uncured rubber and an organic lubricant as a main component.