JPS6233688A - Dyestuff for thermal transfer recording - Google Patents

Abstract

PURPOSE:To obtain a recording of good color density, by using a specific thermal transfer recording cyanine coloring matter, having a preferable hue in terms of color reproducibility, a large molecular absorptivity coefficient, and stabilities to light, moisture, and chemicals, for an ink layer formed on a base film. CONSTITUTION:The coloring matter is shown by a formula 1. (In the formula, X represents hydrogen, alkyl, alkoxy, alkylcarbonyl-amino, or halogen, Y represents hydrogen, alkyl, alkoxy, or halogen, and R<1> and R<2> hydrogen, substituted or non-substituted alkyl or allyl, or aryl.) The ink prepared by a method wherein the coloring matter is dissolved or dispersed in a medium together with a binder is coated and dried on a base film to produce a transfer sheet. This coloring matter has suitabilities for a full color recording with good color reproducibility and a compounding ingredient for black coloring matter, a good subliming properties, and a large molecular absorptivity coefficient, which enables a recording to the performed at high speed without loading a thermal head to a great extent and to have high color density and sperior shelf stability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to dyes used in sublimation type thermal transfer recording.

Conventional technology The thermal transfer method involves heating a transfer sheet with a heat-melting ink layer formed on a base film using a heating means such as a thermal head or infrared rays to melt the ink and transfer it onto a recording medium. There are two types of methods: the melt method, which performs transfer recording, and the sublimation method, which uses a heating means to heat a transfer sheet on which an ink layer containing a sublimable dye is formed on a base film to sublimate the dye, and transfer and record it onto a recording medium. However, the sublimation method can control the amount of sublimation transfer of the dye by changing the energy applied during heating, which facilitates gradation recording and is considered particularly advantageous for full-color recording.

When applying a dye to this recording method, the dye must meet the following conditions.

■ Easily sublimes under the operating conditions of commonly used heating means such as thermal recording heads.

■Do not thermally decompose before sublimation.

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

■ Large molecular extinction coefficient.

■ Stable against light, moisture, chemicals, etc.

■ Easy to synthesize.

■ Excellent suitability for ink production.

Problems to be Solved by the Invention The object of the present invention is to provide a cyan dye that satisfies all of the above conditions.

Means for solving the problems, that is, the present invention solves the following general formula (1) (where xii
Represents a hydrogen atom, an alkyl group, an alkoxy group, an alkylcarbonylamino group, or a halogen atom; Y represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom; R1 and R2 are a hydrogen atom, a substituted or unsubstituted alkyl group , represents an allyl group or an aryl group. ) The gist thereof is a dye for thermal transfer recording shown in the following.

As a method for producing these dyes of the present invention, for example, co-amino-j-nitrothiazole represented by the following structural formula (II) is diazotized by a conventional method, and the following general formula (fir) (wherein X,
Y%H1 and R2 are the same as defined above. Examples of the substituent of the substituted alkyl group coupled with the aniline represented by ) include an alkoxy group, a halogen atom, a cyano group, a hydroxy group, an alkylcarbonyloxy group, an alkoxycarbonyloxy group, and the like.

Particularly preferably, in the general formula (1), R1 and R2 are CI to Cs alkyl groups, 03 to Os
(7) Alkoxyalkyl group, β-chloroethyl group, β
- A cyanoethyl group, a β-hydroxyethyl group, a benzyl group, a 7enethyl group, or an acetyloxyethyl group, where X is a hydrogen atom, a methyl group, a chlorine atom, an acetylamino group, or a propionylamino group, and Y is a hydrogen atom Examples include dyes that are .

When applying the dye of the present invention to a sublimation type thermal transfer recording system, an ink is prepared by dissolving the dye or dispersing it in the form of fine particles in a medium together with a binder, and the ink is applied onto a base film and dried. It is necessary to create a transfer sheet.

Binders for ink preparation include water-soluble resins such as cellulose, acrylic acid, and starch, acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, polyether sulfone, ethyl cellulose, cellulose acetate, polyarylate, etc. Examples include resins that are soluble in organic solvents. In the case of an organic solvent-soluble resin, it is possible to use it not only as an organic solvent solution but also in the form of an aqueous dispersion.

In addition to water, media for preparing ink include alcohols such as methyl alcohol, isopropyl alcohol, and isobutyl alcohol, cellosolves such as methyl cellosolve and ethyl cellosolve, aromatics such as toluene, xylene, and chlorobenzene, ethyl acetate, Esters such as butyl acetate, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, chlorinated solvents such as methylene chloride, chloroform, and trichloroethylene, ethers such as tetrahydrofuran and dioxane, N, N-dimethylformamide, N-
Organic solvents such as methylpyrrolidone may be mentioned.

Suitable base films for applying ink for producing transfer sheets include thin paper such as capacitor paper and glassine paper, and films made of plastics with good heat resistance such as polyester, polyamide, and polyimide.
Their thickness can range from 3 to jO717n.

The ink can be applied to the base film using a reverse roll coater, gravure coater, rod coater, air doctor coater, etc. The thickness of the ink coating layer after drying is 0.7~ It is sufficient to apply the coating so that the coating is within the range of Jμm (Yuji Harasaki, “Coating Method”, published by tDt Shoten in 1992).

Effects of the Invention The azo riazo dye shown in the above (1) of the present invention is suitable for obtaining full color green with good color reproducibility by combining with appropriate yellow and magenta colors. Furthermore, it is suitable as a blending component for black dyes, and because it sublimes easily and has a large molecular extinction coefficient, it can record at high speed and with high color density without placing a large burden on heating means such as thermal heads. Obtainable. Furthermore, it is stable against heat, light, moisture, chemicals, etc., and does not undergo thermal decomposition during transfer recording, and the obtained recording has excellent storage stability. Furthermore, since the dye of the present invention has good solubility in organic solvents and good dispersibility in water, it is easy to prepare a uniformly dissolved or dispersed ink with high concentration, and by using such ink, It is possible to obtain a transfer sheet on which the dye is uniformly coated at a high concentration. Therefore, by using these transfer sheets, recording with good uniformity and color density can be obtained.

EXAMPLES The present invention will be explained in detail with reference to Examples below, but these Examples do not limit the present invention.

Example/(PL) Preparation of ink The above pigment /θ was cellulose acetate (manufactured by Daicel IoT Chemical Co., Ltd., L-3o) A mixture having the above composition was treated with a paint conditioner for 70 minutes to prepare an ink. The pigment and resin were completely dissolved, and an ink with a uniform solution could be obtained.

('b) Preparation of transfer sheet The above ink was coated with a bar coater (RK Pri, ntCo
A transfer sheet was obtained by coating the polyimide film (thickness: /jμm) using A/) manufactured by AT Instruments, and then drying it.

(Q) Transfer Recording The ink-coated surface of the above transfer sheet was placed on the recording medium and recorded using a thermal head under the following conditions.
It was possible to obtain 30 records of uniform color density.

Recording conditions Main scanning and sub-scanning linear density: Dadot/Cod Recording power:
Q, ≦W/Heating time of dot head: / Omeec Note that the recording medium was an aqueous dispersion of saturated polyester 3% by weight (manufactured by Toyobo Co., Ltd., Pyronal MD-/Co00, trade name) 10t and 7% by weight. (Nippon Sirikani Co., Ltd. Rizo, N
1 psi]! A liquid prepared by mixing 1, 2 θA, trade name)/2 was applied to synthetic paper (/10 μm thick) using a percoater (RK Pr1nt Coat instrument).
Manufactured by S company, A-? ) was applied and dried.

Color density was measured using Tensitometer RD manufactured by Macbeth, USA.
-! /D type (filter: Measured using Ratten A2).

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 ≤3±-℃), but after qo waiting period irradiation, the color almost changed and faded. There wasn't. Furthermore, the transfer sheet and recording were stable against heat and moisture, and had excellent storage stability in the dark.

Example λ Ink was prepared, a transfer sheet was prepared, and transfer recording was carried out in the same manner as in Example using the dyes shown in Table 1 instead of the dyes used in Example. Holes that allow you to get a clear record of color density showing.

Claims (1)

[Claims] (1) General formula [I] ▲Mathematical formulas, chemical formulas, tables, etc.▼[I] (In the formula, X represents a hydrogen atom, an alkyl group, an alkoxy group, an alkylcarbonylamino group, or a halogen atom,
Y represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and R^1 and R^2 represent a hydrogen atom, a substituted or unsubstituted alkyl group, an allyl group, or an aryl group. ) A dye for thermal transfer recording.