JP2583425B2 - Thermal transfer recording medium - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermal transfer recording medium which is excellent in thermal transferability particularly at high-speed printing and gives a high-resolution printed image.

(Prior Art) In recent years, the thermal transfer recording method using a thermal head has advantages such as noiselessness, relatively inexpensive and compact device, easy maintenance, and stable printed image. Has become widely used. As a thermal transfer recording medium used in such a thermal transfer recording method, for example, on one surface of a substrate having excellent thermal conductivity and heat resistance such as a capacitor paper or a polyester film, natural wax, waxes such as synthetic wax, A colorant, a thermoplastic resin, or the like is mixed or laminated to provide a heat-meltable color material layer.

However, the heat transfer recording medium provided with the conventional heat-fusible color material layer has a drawback that the transfer rate and resolution of the obtained printed image are not sufficient, particularly when transferring with a short heating time such as during high-speed printing. there were.

(Purpose) An object of the present invention is to provide a thermal transfer recording medium that is excellent in thermal transferability during high-speed printing and that provides a high-resolution printed image.

(Structure) The thermal transfer recording medium of the present invention has a heat-fusible color material layer on a support, and the color material layer (regardless of a single-layer structure or a multi-layer structure).
The compound represented by the following general formula (I) is contained in an arbitrary layer in the case of a multilayer structure).

(Wherein, R is a group having 2 to 2 carbon atoms having 1 to 4 ether bonds)
20 represents a chain hydrocarbon group, and n represents an integer of 1 to 4. The compound of the above general formula (I) has a melting point of 50 to 200 from the viewpoint of storage stability as a thermal transfer recording medium and thermal sensitivity for the purpose.
C., preferably 60 to 150C.

Hereinafter, specific examples of the compound of the general formula (I) are shown, but the present invention is not limited thereto.

Compound No. Structural formula Many of these compounds have a melting point of 50-200 ° C,
The melting point width is as narrow as 0.5 to 1 ° C.

The reasons why the above compounds are preferable as constituent materials of the colorant layer of the thermal transfer recording medium are as follows. Each of these compounds is a single compound and has a sharp melting point and a molecular structure of a polar group and a nonpolar group. It is considered to be a non-ionic surfactant-like structure composed of the following, and as a result, the wettability to an object to be transferred (such as paper) is improved, resulting in excellent transferability during high-speed printing.

As the support of the thermal transfer recording medium of the present invention, for example, polyester, polycarbonate, triacetyl cellulose, nylon, other than a relatively heat-resistant plastic film such as polyimide, glassine paper, capacitor paper, metal foil and the like and A composite of materials can be exemplified.

Examples of the composite include an aluminum / paper composite,
Metal-deposited paper or metal-deposited plastic film can be used. The thickness of the support is preferably about 2 to 15 microns when a thermal head is considered as a heat source at the time of thermal transfer. For example, a heat source that can selectively heat a thermal transferable ink layer such as a laser beam is used. There is no particular limitation in the case. When using a thermal head, provide a heat-resistant protective layer made of silicone resin, fluorine resin, polyimide resin, epoxy resin, phenol resin, melamine resin, nitrocellulose, etc. on the surface of the support that comes into contact with the thermal head. Thereby, the heat resistance of the support can be improved, or a support material that could not be used conventionally can be used.

As the colorant, among organic or inorganic dyes or pigments, those having suitable properties as a recording material are preferable. For example, those having a sufficient coloring density and not discoloring by light, heat, humidity and the like are preferable. In addition, a substance which is colorless when not heated but develops a color when heated, or a substance which develops a color when it comes into contact with a substance applied to a transfer receiving body may be used.

Next, a method for producing a thermal transfer recording medium using the support, the colorant, and the compound described above will be described.
The colorant and the above compound may be kneaded to form a composition, and the composition may be applied to one surface of the support by an appropriate coating method.

As a composition, the weight of the colorant and the above compound is 1 to 80%, preferably 5 to 30%, based on the total weight thereof.
%, And optional components are added as necessary, and kneaded at room temperature or under heating.

In the above, optional components include, for example, a flexibility imparting agent such as a mineral oil or a vegetable oil, a thermal conductivity improving agent such as a metal powder, a microsilica, a calcium carbonate, a pigment such as kaolin, and a transferability improving agent such as a polyhydric alcohol. , Solvents or diluents.

The solvent or diluent is used when the composition is used as an ink composition for an ordinary printing method, and examples thereof include toluene, xylene, ethyl acetate, methyl ethyl ketone, acetone, methanol, ethanol, isopropanol, ethyl cellosolve, and cyclohexanone.

As a method of applying on one surface of the support using the composition comprising the above, in addition to hot melt coating, gravure coat, roll coat, air knife coat, wire bar coat, gravure printing, gravure offset printing, silk screen A printing method such as printing may be used.

If necessary, a wax such as paraffin wax, polyethylene wax, candelilla wax, carnauba wax, or a thermoplastic resin such as EVA or EEA may be added, or a multilayer may be formed.

The thickness of the transfer layer provided as described above is 0.1 to 3
0 μm, preferably 1 to 20 μm. If it is less than 0.1 μm, the print density does not increase, and if it exceeds 30 μm, the thermal conductivity becomes poor and transfer is not sufficient.

 Next, the present invention will be described in more detail with reference to examples.

Example 1 A color material layer dispersion was prepared according to the following formulation by using a ball mill and dispersing while heating to about 50 ° C.

This dispersion is heated on a 3.5 µm thick polyester film with a heat-resistant layer on the back, and the dry adhesion is 8 to 9 g / m.
² and dried to form a thermal transfer recording medium (a)
It was created.

2.5 g of black dye (Kayaset Black KR, manufactured by Nippon Kayaku) (5'-hydroxy-3'-oxapentyl) -12-hydroxystearate 10 g (compound of specific example No. 2, melting point 65-66 ° C.) toluene 70 g Example 2 A colorant layer dispersion was prepared according to the following formulation, and a thermal transfer recording medium (b) was prepared in the same manner as in Example 1.

2.5 g of black dye (Kayaset Black KR manufactured by Nippon Kayaku) (8'-hydroxy-3 ', 6'-dioxaoctyl)-
12-Hydroxystearate 10 g (compound of Compound No. 3; melting point: 62 to 63 ° C.) Toluene 70 g Comparative Example 1 A colorant layer dispersion having the following formulation was prepared, and a thermal transfer recording medium was prepared in the same manner as in Example 1. (C) was created.

2.5 g of black dye (Kayaset Black KR manufactured by Nippon Kayaku) 10 g of paraffin wax (HNP-10 manufactured by Nippon Seiro) 70 g of toluene Thermal transfer recording media (a) to (c) obtained as described above
Using the thermal transfer printer EPSON AP-80K NORMAL
Printing was performed at the HIGH setting and head energy standard (80 characters / second). Copy paper having a Beck smoothness of 60 seconds was used as the receiving paper. Table 1 shows the density and resolution of the printed image.

Concentration: Measured with a Masbeth densitometer RD-514 (filter-W-106).

Resolution: ：: High resolution such as printed and clear prints 鮮: Slightly unclear, but characters can be read. ×: Extremely unclear and difficult to read characters. (Effect) As is apparent from the above description, the present invention The thermal transfer recording medium is excellent in thermal transferability at the time of high-speed printing and can provide a high-resolution printed image.

Claims (1)

(57) [Claims] 1. A thermal transfer recording medium having a heat-fusible colorant layer on a support, wherein the colorant layer contains a compound represented by the following general formula (I). (Wherein, R is a group having 2 to 2 carbon atoms having 1 to 4 ether bonds)
20 represents a chain hydrocarbon group, and n represents an integer of 1 to 4. )