JPH0725224B2 - Thermal transfer recording medium - Google Patents

Description

The present invention relates to a novel thermal transfer recording medium, and more particularly to a thermal transfer recording medium which has a strong fixing strength with respect to a transfer material, is excellent in stain resistance, and can obtain a clear printed image.

In recent years, thermal printers have been widely used because of their compact size, maintenance-free performance, low noise, and the like. For this thermal printer, one using a color-developing heat-sensitive recording paper and one using a thermal transfer recording medium have been proposed, but the former has the drawback that the storability and fastness of the record are not sufficient. Recently, the latter has been widely adopted.

Further, according to the method using the thermal transfer type recording medium, it is possible to record on a printing material which could not be printed by a conventional color development type thermal printer or an impact printer using a liquid ink at room temperature. Taking advantage of its features, it has been used for new applications such as various cards and labels.

Due to their properties, these cards, labels, etc. are often used under extremely severe conditions compared to the environments such as offices where conventional thermal transfer recording media have been used. The adhesive strength was poor and the abrasion resistance was poor, and the stain resistance such as water resistance was not sufficient.

The present invention solves the above-mentioned drawbacks and provides a thermal transfer type recording medium which has high adhesion strength to a material to be transferred, excellent friction resistance and good stain resistance such as water resistance and is suitable for recording cards and labels. To do. That is, as a result of earnest research by the present inventor, the present invention provides a heat-fusible ink layer on a base material and a resin adhesive layer on the ink layer to improve the adhesion strength to a transfer material and stain resistance. It has been found that the above-mentioned improvement is also achieved and the present invention has been achieved.

The resin adhesive layer of the present invention can be obtained by dissolving a thermoplastic resin in a solvent for the resin and coating it on the heat-meltable ink layer. The resin has high adhesive strength with the heat-fusible ink layer and all materials to be transferred, and has a softening point or melting point of 50 ° C to 180 ° C.
The thing of 60 degreeC-130 degreeC can be used suitably. If the temperature is 50 ° C or lower, blocking occurs during high temperature storage such as in the summer, and if the temperature is 180 ° C or higher, a large amount of energy is required for printing, and sufficient melting is not performed in actual use, which is a cause of defective printing, which is not preferable.

Examples of these resins include acrylic resin amide resin, ketone resin, polystyrene resin rosin resin phenol resin, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer and the like. These resins are coated by solvent coating to have a thickness of about 0.2 μm to 2 μm. If it is 0.2 μm or less, the effect is small, and if it is 2 μm or more, it is not preferable because it does not melt or soften sufficiently during printing and causes defective printing.

Next, the heat-meltable ink layer used in the thermal transfer recording medium of the present invention is a conventionally known one composed of a coloring agent such as a dye, an organic pigment and an inorganic pigment, a binder agent, and a softening agent. Examples of the agent include natural waxes such as carnauba wax and candelilla wax, petroleum waxes such as microcristan wax and paraffin wax, coal waxes such as montan, and synthetic waxes. Examples of the softening agent include animal vegetable oil, mineral oil, petrolatum and petroleum resin. The hot melt ink layer is formed from these compositions by a conventionally known method such as hot melt coating or solvent coating.

The substrate used in the thermal transfer recording medium of the present invention includes
For example, paper such as condenser paper, synthetic resin film such as cellophane, polyester, polycarbonate, polyimide, etc. are appropriately used.

Next, examples of the present invention will be described.

Example 1 Paraffin wax (145F) 35 parts Carnauba wax 30 parts Lanolin 10 parts Alcon P (Arakawa Hayashi Chemical Petroleum Rosin) 15 parts Carbon black 10 parts The above composition is treated with an attritor at 100 ° C. for 2 hours to obtain carbon black. Dispersed. This hot melt ink was applied to a condenser paper in a layer having a thickness of 4 μm by hot melt coating.

Next, as a resin adhesive layer, 10 parts of Versamide 711 (manufactured by Henkel Japan Ltd., polyamide) is dissolved in 90 parts of ethanol, and a 1.5 μm-thick layer is coated on the heat-meltable ink layer to form a thermal transfer recording medium. And

When this thermal transfer recording medium was used to print on a polypropylene label with a thermal printer, clear printing was obtained. Even if you strongly rub this print with your finger, the print will not come off,
It had good abrasion resistance. Next, when this label was immersed in water for 1 hour and taken out and rubbed with a finger, the print had no peeling and had good water resistance.

Example 2 Paraffin wax (135F) 20 parts Carnauba wax 35 parts NPS6115 (Nippon Seiwa Co., Ltd. oxidized microcrystalline wax) 25 parts Vaseline 5 parts Carbon black 15 parts The above composition was treated with an attritor at 100 ° C. for 2 hours, and carbon Dispersed black. This hot-melt ink was coated by hot-melt coating on a polyester film having a thickness of 9μ to form a layer having a thickness of 4μ.

Next, as a resin adhesive layer, 10 parts of Hilac 222 (a ketone type resin manufactured by Hitachi Chemical Co., Ltd.) was dissolved in 90 parts of methyl ethyl ketone, and a 1 μm-thick layer was coated on the hot melt ink layer to form a thermal transfer recording medium. did. When a thermal printer was used to print on a polypropylene label using this thermal transfer recording medium, clear printing was obtained. When this printed matter was tested in the same manner as in Example 1, good results were obtained.

Comparative Example 1 The heat-fusible ink layer of Example 1 was applied to a capacitor paper in a thickness of 4
What was applied to the μ layer by the hot mel coating method was used to print on a polypropylene label with a thermal printer. When this printed image was strongly rubbed with a finger, the printed image disappeared and became unreadable. Then, the printed image was immersed in water for 1 hour and then taken out and lightly rubbed with a finger, the printed image peeled off and became unreadable.

Comparative Example 2 A polypropylene label was printed with a thermal printer by using the hot-melt ink layer of Example 2 coated on a 9 μm thick polyester film by a hot melt coating method on a 4 μm thick layer. When this printed image was strongly rubbed with a finger, the print came off and became unreadable. Next, when the printed image was immersed in water for 1 hour and then taken out and lightly rubbed with a finger, the printed image peeled off and became unreadable.

As described above, the present invention provides a thermal transfer type recording medium which is suitable for cards, labels, etc., because it provides a clear and solid image having excellent stain resistance such as abrasion resistance and water resistance.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a thermal transfer recording medium of the present invention, and FIG. 2 is a vertical sectional view of a conventional thermal transfer recording medium. 1 ... Substrate 2 ... Hot-melt ink layer 3 ... Resin adhesive layer

Claims (1)

[Claims] 1. An acrylic resin, an amide resin, a ketone resin, a polystyrene resin having a heat-meltable ink layer formed on a substrate and having a softening point or a melting point of 50 ° C. to 180 ° C. on the ink layer. A thermal transfer recording medium, wherein a resin adhesive layer having at least one thermoplastic resin selected from a vinyl chloride-vinyl acetate copolymer is provided.