JP2552486B2 - 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. Examples of the thermal transfer recording medium used in such a thermal transfer recording method include waxes such as natural wax and synthetic wax on one surface of a substrate having excellent thermal conductivity and heat resistance such as condenser paper and polyester film, A colorant, a thermoplastic resin, etc. are mixed or laminated to provide a heat-fusible color material layer.

However, the thermal transfer recording medium provided with the above-mentioned conventional heat-fusible color material layer has a drawback that the transfer rate and resolution of a print image to be obtained are not sufficient especially when transferring in a short heating time such as high-speed printing. there were.

(Object) It is an object of the present invention to provide a thermal transfer recording medium which is excellent in thermal transfer property during high speed printing and gives 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).

(In the formula, R has 2 to 5 carbon atoms and has 1 to 5 hydroxyl groups.
Represents a chain hydrocarbon group of ~ 24, X ₁ , X ₂ X ₃ , X ₄ , X ₅ , X ₆
Each independently represents a group selected from a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a halogen atom, an alkoxyl group, an aryl group, and an aralkyl group.) The compound of the general formula (I) is used as a thermal transfer recording medium. Melting point 50-200 from the viewpoint of storage stability and thermal sensitivity for this 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.

Most of these compounds have a melting point of 50 to 200 ° C.,
The melting point width is as narrow as 0.5 to 1 ° C.

The reason why the above compound is preferable as a constituent material of the color material layer of the thermal transfer recording medium will be described. All of these compounds are single compounds, have a sharp melting point, and have a molecular structure of polar group and nonpolar group. It has a nonionic surfactant-like structure consisting of and improves the wettability to the transferred material (paper or the like), so that the transferability during high-speed printing is considered to be excellent.

As the support of the thermal transfer recording medium of the present invention, for example, polyester, polycarbonate, triacetyl cellulose, nylon, other relatively heat-resistant plastic film such as glass, glassine paper, condenser paper,
Examples include metal foils and composites of the above materials.

Examples of the composite include an aluminum / paper composite,
Examples thereof include metal evaporated paper, metal evaporated plastic film and the like. When considering the thermal head as a heat source for thermal transfer paper, the thickness of the support is preferably about 2 to 15 microns, but for example, a heat source that can selectively heat the thermal transferable ink layer such as laser light is used. If so, there is no particular limitation. 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 contacts the thermal head. According to this, the heat resistance of the support can be improved, or a support material which cannot 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. Further, it may be a substance which is colorless when not heated, but which develops a color when heated, or a substance which develops a color when brought into contact with a substance applied to the transfer target.

The support, the colorant, and the method for producing a thermal transfer recording medium using the above compound will be described below.
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 the composition, the weight of the colorant and the above compound is 1 to 80% of the total weight thereof, preferably 5%.
It is blended so as to be 〜30%, and in addition, an optional component is added as required, and kneaded at room temperature or under heating.

Examples of the optional component in the above include a flexibility imparting agent such as mineral oil or vegetable oil, a thermal conductivity improving agent such as metal powder, a pigment such as microsilica, calcium carbonate and kaolin, and a transferability improving agent such as polyhydric alcohol. , Solvents, diluents, and the like. The solvent or diluent is used when the composition is used as an ink composition for a normal printing method,
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
It is 0 μm, preferably 1 to 20 μm. If it is less than 0.1 μm, the printing density does not increase, and if it exceeds 30 μm, the thermal conductivity becomes poor and the transfer is not sufficiently performed.

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

Example 1 A coloring material layer solution was prepared according to the following formulation, and applied on a polyester film having a thickness of 3.5 μm so that the dry adhesion amount was 8 to 9 g / m ^2, and dried to obtain the thermal transfer recording medium (a). Created.

Black dye (Nippon Kayaku Kayaset Black KR) 2.5g 1,3-diphenoxy-2-propanol (Compound Specific Example N
Compound of o.2, melting point 76-77 ° C) 10 g Acetone 12.5 g Example 2 A color material layer dispersion having the following formulation was prepared, and a thermal transfer recording medium (b) was prepared in the same manner as in Example 1.

Black dye (Nippon Kayaku Kayaset Black KR) 2.5g 1,2-diphenoxy-1-propanol (Compound Specific Example N
Compound of o.1, melting point 78-79 ° C) 10 g Acetone 12.5 g Example 3 A color material layer dispersion having the following formulation was prepared, and a thermal transfer recording medium (c) was prepared in the same manner as in Example 1.

Black dye (Kayaset Black KR manufactured by Nippon Kayaku) 2.5 g 1,4-diphenoxy-2,3-butanediol (compound of specific example No. 5, compound, melting point 101 to 102 ° C.) 10 g acetone 12.5 g Comparative Example 1 A color material layer dispersion having the following formulation was prepared, and a thermal transfer recording medium (d) was prepared in the same manner as in Example 1.

Black dye (Nippon Kayaku Kayaset Black KR) 2.5 g Paraffin wax (NIPPON SEIRO, HNP-10) 10 g Toluene 60 g Thermal transfer recording media (a) to (d) obtained as described above.
Using a thermal transfer printer EPSON AP-80K with NORMAL HI
Printed with GH (80 characters / second) and head energy standard. A copy paper having a Beck smoothness of 200 seconds was used as the transfer paper. The results are shown in Table-1.

Density: Measured with Macbeth densitometer RD-514 (filter W-106).

Image resolution: Visually.

5: The resolution is good and clear like ordinary printed matter.

3: Low resolution but legible.

2: Barely readable.

1: Almost unreadable.

(Effect) As is clear from the above description, the thermal transfer recording medium of the present invention is excellent in thermal transfer property during 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). (In the formula, R has 2 to 5 carbon atoms and has 1 to 5 hydroxyl groups.
Represents a chain hydrocarbon group of ~ 24, X ₁ , X ₂ X ₃ , X ₄ , X ₅ , X ₆
Each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a halogen atom, an alkoxyl group, an aryl group or an aralkyl group.)