JP2571218B2 - Thermal transfer recording medium - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermal transfer recording medium for performing thermal transfer recording on recording paper utilizing the thermal fusibility of an ink layer, and relates to a printer such as a computer and a word processor, and a bar code. It can be applied to printers and the like.

[Prior Art] A heat-fusible substance such as paraffin wax and a dye,
A thermal transfer medium in which a transfer layer formed of a coloring agent such as a pigment is provided on a support is known. However, paraffin wax has a drawback that the mechanical strength is weak, so that the friction resistance of a transferred image is poor. .

In order to remedy this drawback, a method of adding a thermoplastic resin or making the transfer layer as thin as possible has been adopted.However, in the former case, when the resin component is increased, the adhesive force becomes stronger and transfer becomes difficult, or heat transfer becomes difficult. There is a problem that the sensitivity is deteriorated, and the latter problem is that the uniformity of the transferred image is deteriorated and the image density is reduced.

[Purpose] The present invention solves the above-mentioned problems of the prior art, and provides a high-density and uniform transfer image on a recording paper, and a thermal transfer method capable of obtaining a transfer image excellent in friction resistance. It is intended to provide a recording medium.

[Structure] In order to achieve the above object, the structure of the present invention is to form a first transfer layer having the following structure (1) and a second transfer layer having the following structure (2) on a support. It is a thermal transfer recording medium having sequentially.

(1) A first transfer layer comprising, as main components, resin particles having a melting point or softening point in the range of 75 to 140 ° C, and wax having a melting point or softening point in the range of 70 to 130 ° C.

(2) a second component comprising, as main components, a dye and / or a pigment, resin particles having a melting point or softening point in the range of 60 to 110 ° C, and a wax having a melting point or softening point in the range of 70 to 130 ° C. Transfer layer.

The transfer layer of the thermal transfer recording medium of the present invention is overlapped with the recording paper, and a desired image is formed on the recording paper by thermal printing from the back surface of the thermal transfer recording medium.

As the support of the thermal transfer recording medium in the present invention, various conventionally known supports can be appropriately used.

Examples thereof include a plastic film such as a polyester film, a polyamide film, a polyvinyl chloride film, a polyethylene film, a polypropylene film, a polyimide film, a polysulfone film, and a polycarbonate film, and a condenser paper.

As the dyes and pigments used in the present invention, inorganic and organic dyes and pigments used in printing inks, paints and the like can be used. Specific examples include carbon black, disazo yellow, brilliant carmine 6B, lake red C, phthalocyanine blue, Kayaset Black KR (Nippon Kayaku), oil yellow 3G (Orient Chemical), Kayaset Red K-BE (Nippon Kayaku), Kaya set blue KFL
(Nippon Kayaku).

As the resin used for the resin particles, various resins having a melting point or a softening point (ring and ball method JIS K 2531) of 60 to 140 ° C. can be used.

Examples include acrylic resins, methacrylic resins, styrene resins, vinyl acetate resins, vinyl chloride resins, vinylidene chloride resins, petroleum resins, novolak resins, olefin resins, polyester resins, polyacetal resins, epoxy prepolymers, and copolymers of these. . Further, a plasticizer can be used as needed to adjust the melting point or softening point of the resin particles.

For example, dimethyl phthalate, diethyl phthalate,
Dibutyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, di-2-ethylhexyl adipate, diethylene glycol dibenzoate, butyl stearate, triphenyl phosphate and the like.

If the melting point or softening point of the resin particles used for the first transfer layer is lower than 75 ° C., the friction resistance of the transferred image in a high temperature environment (50 to 60 ° C.) is deteriorated. It is difficult to fix enough with energy alone,
If the friction resistance is inferior, otherwise high energy recording is required, problems such as a decrease in recording speed and a shortened life of the thermal head occur.

If the melting point or softening point of the resin particles used for the second transfer layer is lower than 60 ° C., the transfer layer may cause blocking while the thermal transfer recording medium is stored, and if it is higher than 110 ° C., the uniformity of the transferred image may be reduced. It is not preferable because the property deteriorates.

The resin particles used in the present invention can be obtained by making various resins into fine particles (e.g., emulsion polymerization, a wet dispersion method using a sand mill, a dry dispersion method using a jet mill, etc.).

The average diameter of the resin particles is preferably 0.1 to 5 μm, particularly preferably about 1 to 3 μm. If it is less than 0.1 μm, sticking tends to occur during transfer, and if it exceeds 5 μm, thermal sensitivity and resolution deteriorate, which is not preferable.

As the wax used in the present invention, a wax having a melting point or a softening point of 70 to 130 ° C is suitable.

If the melting point or softening point of the wax is lower than 70 ° C., the applied thermal energy is consumed to melt the wax, so that the energy for softening the resin is insufficient. For this reason, only the wax is preferentially transferred, and the transfer of the transfer layer is insufficient, resulting in a blurred transferred image and reduced sharpness. If the temperature is higher than 130 ° C., high energy is required for transfer.

Further, the penetration of such a wax is preferably 1 or less, and if the penetration is greater than 1, scratch resistance of a recorded image is reduced.

Specific examples include carnauba wax, polyethylene wax, Fischer-Tropsch wax, montan wax derivatives, and hardened castor oil.

The amount of the wax used affects the thermal sensitivity and the abrasion resistance of the thermal transfer image. The use ratio of the wax is preferably 10 to 70% by weight of the total solid content of the transfer layer. If the amount is less than 10% by weight, a uniform transfer image cannot be obtained. If the amount exceeds 70% by weight, the abrasion resistance becomes poor. Not preferred.

In addition, a binder other than wax can be used as appropriate for the transfer layer of the present invention. However, the amount of the binder should be minimized so as not to hinder transfer, and 0 to 25% by weight of the total solid content of the transfer layer. It is about. Conventional binders can be used as these binders, for example, polyvinyl alcohol, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyacrylamide, starch, gelatin,
Examples include acrylic resin, methacrylic resin, vinyl acetate resin, vinyl chloride resin, vinylidene chloride resin, olefin resin, polyester resin, and copolymers thereof.

As the recording paper used together with the thermal transfer recording medium of the present invention, plain paper, synthetic paper, plastic film and the like can be appropriately used.

In the thermal transfer recording medium of the present invention, the above-mentioned transfer layer forming component is mixed with water or a solvent that does not dissolve the resin particles, and the average particle diameter of the resin particles becomes 0.1 to 5 μm by a dispersion means such as a stirrer, a ball mill, and an attritor. dispersed allowed to which the amount of total solids deposited on the support. the coating is a 1 to 10 g / m ^2, so as not allowed fusing resin particles,
It can be produced by drying at a temperature below the softening point of the resin particles.

[Examples] Next, the present invention will be described in more detail with reference to Examples. In the following, “parts” and “%” are based on weight.

1. Preparation of Carbon Black Dispersion Carbon black 20 parts Surfactant 2 parts Water 78 parts The material having the above composition was dispersed in a ball mill for 24 hours.

2.Preparation of resin particle dispersion The materials shown in Table 1 were dispersed in a ball mill for 24 hours to obtain a dispersion of resin particles having an average particle size of 2 μm.

Examples 1 to 6 Preparation of coating solution for first transfer layer The compositions described in Table 2 above were uniformly mixed with a stirrer.

Preparation of coating solution for second transfer layer The compositions described in Table 3 above were uniformly mixed with a stirrer.

Preparation of Thermal Transfer Recording Medium The first transfer layer coating solution (Table 2) was coated on a 6 μm-thick polyester film using a wire bar so that the adhesion after drying was 2 g / m ² , and then heated with hot air. (40-50 ° C) dried.

Next, a coating liquid for the second transfer layer (Table 3) was similarly applied onto the first transfer layer such that the amount of adhesion after drying became 2 g / m ² and dried. Thermal transfer recording media having the combinations shown in Table 4 were produced.

Comparative Example 1 The coating liquid No. 2 was dried so that the amount of adhesion after drying was 4 g / m ^2.
It was applied to a μ-thick polyester film and dried to prepare a thermal transfer recording medium.

Comparative Example 2 A thermal transfer recording medium was prepared in the same manner as in Comparative Example 1 except that the coating liquid No. 6 was used.

Comparative Examples 3 and 4 In the same manner as in Examples 1 to 6, a thermal transfer recording medium was obtained.

The thermal transfer recording medium produced as described above was printed by applying the energy of 0.5 mJ / dot using a thermal transfer printer with the transfer layer in close contact with the surface of the high quality paper. Further, in order to examine the rub resistance of the printed image, a lab tester (manufactured by Toyo Seiki Co., Ltd.)
0, 50 ° C).

 The results were as shown in Table 6 below.

[Effects] As described above, by using the thermal transfer recording medium of the present invention, a transferred image having high density, good uniformity, and excellent friction resistance can be obtained.

Continuation of the front page (56) References JP-A-61-78692 (JP, A) JP-A-60-236790 (JP, A) JP-A-58-219086 (JP, A) Jpn. , U) Jikai Sho 57-199472 (JP, U) JP-B 54-10495 (JP, B2)

Claims (1)

(57) [Claims] 1. A thermal transfer recording medium comprising a support and a first transfer layer having the following configuration (1) and a second transfer layer having the following configuration (2). (1) A first transfer layer comprising, as main components, resin particles having a melting point or softening point in the range of 75 to 140 ° C, and wax having a melting point or softening point in the range of 70 to 130 ° C. (2) A second component comprising, as main components, a dye and / or a pigment, resin particles having a melting point or softening point in a range of 60 to 110 ° C, and a wax having a melting point or softening point in a range of 70 to 130 ° C. Transfer layer.