JPS6339380A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To enable easy preparation of high density ink and a recording of high uniformity and chromatic density to be available by using a specific yellow pigment. CONSTITUTION:A coloring material layer containing a pyridone azo pigment is provided on a base film as shown in the formula. When applying a pigment to a thermal transfer sheet, the ink is conditioned by melting a pigment into a medium together with a binding agent or dispersing the pigment in fine particles. Then the ink is applied and dried on the base film to form a coloring material layer. The pyridone azo pigment has a sharp yellow color, so that this color is suitable for obtaining a full color recording with a high chromatic reproducibility by combining it with proper magenta and cyan colors. In addition, a high color density recording can be obtained at high speed. In the formula, R1 represents an alkyl group of 1-8C, an alkoxyalkyl group of 3-8C, a cycloalkyl group or aryl group, R2 represents an alkyl group of 1-8C, an alkoxyalkyl group of 3-8C, an aralkyl group of 7-8C and a cycloalkyl group or an aryl group.

Description

[Detailed Description of the Invention] 卆benjukuretsu (Industrial Application Field) The present invention is based on the Sho 4! The present invention relates to a transfer sheet used for thermal transfer recording.

(Prior Art) Techniques for color recording facsimile printers, copying machines, television images, etc. have been highly desired, and color recording techniques using electrophotography, inkjet, thermal transfer, etc. are being considered.

The thermal transfer recording method is considered to be advantageous over other methods because the device is easy to maintain and operate, and the device and consumables are inexpensive.

Thermal transfer methods include a melting method in which a transfer sheet with a heat-melting ink layer formed on a base film is heated by a thermal head to bath-melt the ink and transfer recording onto a recording medium; There is a sublimation method in which a transfer sheet on which an ink layer containing a collimating dye is formed is heated with a thermal head to sublimate the dye, and the transfer marks are recorded on the recording medium. Since this method can control the amount of dye sublimation transfer by changing the energy applied to the thermal head, it facilitates gradation recording and is considered particularly advantageous for full-color recording.

In thermal transfer recording using the sublimation method, the sublimable dye used in the transfer sheet is extremely important because it has a great effect on the speed of transfer recording, the image quality of the recorded material, and the storage stability.The following conditions must be met. It is necessary to fulfill the requirements.

■ Easily sublimated under the operating conditions of the thermal recording head.

■Do not thermally decompose under the operating conditions of the thermal recording head.

■ It must have a favorable hue in terms of color reproduction.

■ High molecular extinction coefficient.

C5) Stable against heat, light, moisture, chemicals, etc.

■ Easy to synthesize.

■ Excellent suitability for ink production.

Until now, no dye has been found that satisfies all of the above conditions, and yellow dyes in particular have various drawbacks and have not yet been found to be satisfactory.

(Problems to be Solved by the Invention) An object of the present invention is to provide a heat-sensitive transfer sheet characterized by using a yellow dye that satisfies all of the above conditions.

(Means for Solving the Problem) The present invention provides a base film with the following general formula [I] 1
.

(In the formula, R1 represents a C1-c alkyl group, 03-o8 noalkoxyalkyl group, cycloalkyl group, or allyl group, and R2 represents a C1-c8 alkyl group, 03-C8
an alkoxyalkyl group, a C7-c8 aralkyl group,
The gist thereof is a heat-sensitive transfer sheet characterized by having a coloring material layer containing a pyridone azo dye represented by a cycloalkyl group or an allyl group.

The pyridone azo dye represented by the general formula CI) used in the present invention will be briefly explained.

Examples of the alkyl group of 01 to C8 in R1 include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, and octyl group. In either case, the wave is especially C, -0
, lower alkyl groups are preferred. Examples of C3 to C8 alkoxyalkyl groups include β-methoxyethyl group, β-ethoxyethyl group, β-(n)propoxyethyl group, β-
(1 day O) propoxyethyl group, β-(n) butoxyethyl group, β-(1θ0)butoxyethyl group, β-(θe
c) Butoxyethyl group, β-(n) bentoquinethyl group, β-(n) hexylethyl group, /-methyl-comethoxyethyl group, /-methyl-j-ethogynethyl group, 3
Examples include -methoxybutyl group, 3-ethoxybutyl group, /-ethyl-methoxyethyl group, /-ethyl-ethoxyethyl group, and C3 to C6 β-alkoxyethyl group is particularly preferred. Examples of the cycloalkyl group include a cyclopentyl group and a cyclohexyl group.

Examples of the alkyl group for R2 include a methyl group, an ethyl group, a linear or branched propyl group, and a butyl group. As the alkoxyalkyl group of 03 to 08, β-
Methoxyethyl group, β-ethoxyethyl group, β-(n)
Propoxyethyl group, β-(iso)propoxyethyl group, β-(n)butoxyethyl group, β-(180)butoxyethyl group, β-(SθC)7')oxyethyl group, β-(n)pentoxyethyl group group, β-(n)hexylethyl group, γ-methoxypropyl group, γ-(iso)propoxy 7' o hir group, γ-ethoxycpropyl group,
Examples include γ-(n) butquinpropyl group, γ-(n) propoxypropyl group, and especially 03 to C6 β-
Alkoxyethyl groups and C1I-C6 γ-alkoxypropyl groups are preferred. 07-C8 aralkyl, 1-
L-11. Examples include benzyl group and β-phenethyl group. Examples of the cycloalkyl group include cyclopentyl and cyclohexyl.

The dye described in General 20) used in the coloring material layer of the heat-sensitive transfer sheet of the present invention is produced according to a method normally used for producing this type of compound.

For example, a compound represented by the following structural formula [old (wherein R1 is the same as defined above)] is diazotized by a conventional method, and the compound represented by the following general formula (III) (wherein R2 is the same as defined above) is obtained. Obtained by compounding with a salle compound.

When applying the above dye to the thermal transfer sheet of the present invention,
An ink is prepared by dissolving or dispersing the pigment in the form of fine particles in a medium together with a binder, and the ink is applied to a base film, lyFed, and smoked to form a color material layer on the base film. do.

Binders for ink preparation include water-soluble resins such as cellulose, acrylic acid, and starch, acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, polyether sulfone, polyvinyl butyral, ethyl cellulose, acetyl cellulose, etc. Examples include resins that are soluble in organic solvents or water.

In addition to water, media for ink preparation include alcohols such as methyl alcohol, iso7'robil alcohol, and isobutyl alcohol, cellosolders such as methyl cellosolve and ethyl cellosolve, and aromatic compounds such as toluene, xylene, and chlorobenzene. , esters such as ethyl acetate and butyl acetate, ketones such as acetone, methyl ethyl ketone, methyl isobunal ketone, and cyclohexanone, chlorine bath agents such as methylene chloride, chloroform, and trichloroethylene, and ethers such as tetrahydrofuran and dioxane M, N , N-dimethylformamide, N-
Organic solvents such as methylpyrrolidone can be avoided.

In addition to the above-mentioned components, the above ink also contains organic and inorganic non-sublimable fine particles, dispersion wound, charging agent, anti-blocking agent, anti-foaming agent, acid oxidation agent, Viscosity h1η
Conditioners and the like can be added.

Suitable base films for applying ink for making transfer sheets include thin paper such as condenser paper and glassine paper, and plastic films with good heat resistance such as polyester, polycarbonate, polyamide, polyimide, and polyaramid. , their thickness can be in the range of Fi3 to jOμm.

The method of applying ink to the base film is
It can be carried out using an IJ bar roll coater, Clavia coater, rod coater, air doctor coater, etc., and the thickness of the ink coating layer is θ, /~j after drying.
It is sufficient to apply the coating so that the coating frequency is micrometers ("Coating Method", written by Yuji Harasaki, published by Maki Shoten, 7979).

(Operations and Effects of the Invention) Since the pyridone azo dye represented by (r) above used in the heat-sensitive transfer sheet of the present invention has a vivid yellow color, it can be colored by combining it with magenta and cyan colors, which are suitable foils. p+31. It is suitable for obtaining full-color records with good color density, and because it sublimes easily and has a large molecular extinction coefficient, it is possible to obtain records with high color density at high speed without placing a large burden on the sensor or thermal head. . Furthermore, heat, light,
Since it is stable against moisture, chemicals, etc., it does not undergo thermal decomposition during transfer recording, and the resulting recording has excellent storage stability, and is particularly excellent in light resistance. In addition, since the pigment has good solubility in organic solvents and dispersibility in water, it is easy to prepare a highly concentrated ink in which the pigment is uniformly dissolved or dispersed. It is possible to obtain a heat-sensitive transfer sheet coated uniformly and with high concentration. Therefore, recording with good uniformity and color density can be obtained by using such heat-sensitive transfer sheets.

Furthermore, the thermal transfer sheet of the present invention can utilize not only a thermal head but also infrared rays, laser light, etc. as a heating means.
I can do it.

(Examples) The present invention will be specifically explained below with reference to Examples, but these Examples do not limit the present invention.

Example/Pyridone azo dye of the above invention/θV cellulose acetate 10? (Manufactured by Daicel Chemical Co., Ltd., L-Jθ) Methyl ethyl ketone and 02 total
/θ0v The composition of the silk composition was treated with a paint conditioner for 10 minutes to prepare an ink.

b) Transfer sheet work ゛Use a wire bar to apply the above ink to a polyethylene terephthalate film (in μm
The transfer sheet was coated on the film (with a dry film thickness of approx./μm) and dried to obtain a transfer sheet.

In addition, the heat-resistant and slippery treatment of polyethylene terephthalate film is performed by injecting polyethylene terephthalate into it.
．． 1; Polycarbonate resin having a repeating structural unit represented by the following formula? Parts by weight, phosphate ester surfactant/parts by weight (
Product name Nibly Surf A-ko θlB: 1st process! A liquid consisting of 97 accumulated parts of toluene was applied and dried (dried film thickness of about 01 S μm).

C) Creation of image receptor Saturated polyester resin (Product name: 'rp-, zao,
Nippon Gosei Co., Ltd. product) 70 parts, amino-modified silicone (product name: KFJ Ri3, Shin-Etsu Chemical Co., Ltd. product) 0
．． A liquid consisting of 5 parts of methyl ethyl ketone, 775 parts of methyl ethyl ketone, and 1 part of xylene was applied to synthetic paper (product name: Yubo FPG/sO, manufactured by Oji Yuka Co., Ltd.) with a wire bar, dried to form a dry film of about 11 S μm), and then opened. An image receptor was prepared by heat treatment at 700°C for 3θ minutes.

d) Transfer arrangement The ink-applied surface of the above transfer sheet was overlapped with the recording medium and recorded using a thermal head under the following conditions, with a clear yellow color of 0.
It was possible to obtain a record of uniform color density for 9 seconds.

Recording conditions Linear density of main scanning and sub-scanning: Dot/Sea bream recording Power: θ, 2sw/Heating time of dot head: /θm 8θC Densitometer RD-371/L manufactured by Macbeth Co., USA Type (filter:
It was measured using a Wratten Hiroki 7).

A light resistance test of the obtained record was carried out using a carbon arc fade meter (manufactured by Suga Test Instruments Co., Ltd.) (black panel temperature 33±-℃), but after irradiation for a long time the color changed and faded. There wasn't. In addition, the transfer sheet and recording were stable against heat and moisture, and had excellent stability in the dark.

Actual Neutral B Example = 2 Ink preparation, preparation of a transfer sheet, and transfer 1tFf+ were carried out in the same manner as in Example/, using the pigments shown in Table 1 instead of the pigments used in Example/, It was possible to obtain clear yellow Hri records with the color densities shown in Table 1.

The results of the light fastness test of the recording and the dark storage stability test of the transfer sheet and recording were good.

-]5-

Claims (1)

[Claims] (1) Apply the following general formula [I]▲ on the base film,
There are chemical formulas, tables, etc. ▼ (In the formula, R^1 is an alkyl group of C_1 to C_8, C_3
~C_8 represents an alkoxyalkyl group, cycloalkyl group, or allyl group, and R^2 is a C_1 to C_8 alkyl group, a C_3 to C_8 alkoxyalkyl group, C_
7 to C_8 representing an aralkyl group, cycloalkyl group, or allyl group) A heat-sensitive transfer sheet comprising a coloring material layer containing a pyridone azo dye.