JPH0513077B2 - - Google Patents

Description

[Detailed description of the invention]

OBJECT OF THE INVENTION A. Field of Industrial Application The present invention relates to a dye used in sublimation type heat-sensitive transfer recording and a heat-sensitive transfer sheet using the same. B. Prior Art Conventionally, there has been a demand for technology for color recording facsimile printers, copying machines, television images, etc., and color recording technologies 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 heat-sensitive head to 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 sublimable dye is formed is heated by a thermal head to sublimate the dye, and then transferred and recorded onto a recording medium. Since the amount of sublimation transfer of the dye can be controlled by changing the applied energy, gradation recording becomes easy and is considered to be particularly advantageous for full color recording. C. Problems to be Solved by the Invention When a dye is applied to this recording method, the dye must meet the following conditions. Easily sublimated under the operating conditions of a thermal recording head. Do not thermally decompose under the operating conditions of the thermal recording head. Must have a favorable hue in terms of color reproduction. High molecular extinction coefficient. Stable against heat, light, moisture, chemicals, etc. Easy to synthesize. Excellent ink suitability. An object of the present invention is to provide a magenta dye that satisfies all of the above conditions and a heat-sensitive transfer sheet using the dye. That is, the present invention provides the following general formula [] (In the formula, R is a hydrogen atom, a C ₁ to C ₈ alkyl group,
Represents a _C1 - _C8 alkoxy group, a _C3 - _C8 alkoxyalkyl group, or a halogen atom, and X is a methyl group, methoxy group, formylamino group, a _C1 - _C8 alkylcarbonylamino group, or a _C1 -C8 alkoxyalkyl group. represents a C ₈ alkoxycarbonylamino group, Y represents a hydrogen atom, a C ₁ to C ₄ alkoxy group, a methyl group, or a halogen atom; R ¹ and R ² represent _an allyl group;
C ₈ alkyl group, C ₃ to C ₈ alkoxyalkyl group, aralkyl group, hydroxyalkyl group) for thermal transfer recording, and an azo dye represented by the above general formula [] on the base film. The gist thereof is a heat-sensitive transfer sheet characterized by having a coloring material layer containing: As a method for producing these dyes of the present invention, for example, the following general formula [] (In the formula, R is the same as defined above.) The anilines represented by the formula are diazotized according to a conventional method to form the following general formula [] (In the formula, X, Y, R ¹ and R ² are the same as defined above.) The following general formula obtained by coupling with anilines represented by [] (In the formula, R, X, Y, R ¹ and R ² are the same as defined above.) It is obtained by reacting an azo compound represented by the following with copper cyanide in a polar solvent. Among the azo dyes of the present invention, particularly preferred are those in which R represents a water atom, a methyl group, a methoxy group, a chlorine atom, or a bromine atom in the general formula [], and R ¹ and R ² represent C ₁ -C ₈ alkyl group,
Examples include dyes in which X represents a methyl group, a _C1 - _C4 alkylcarbonylamino group, or a _C1 - _C4 alkylsulfonylamino group, and Y represents a hydrogen atom. When applying the dye of the present invention to this recording method, an ink is prepared by dissolving the dye together with a binder in a medium or dispersing it in the form of fine particles, and the ink is applied onto a base film and dried to form a transfer sheet. It is necessary to create one. Binders for ink preparation include water-soluble resins such as cellulose, acrylic acid, and starch, and organic solvent-soluble resins such as acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, polyethersulfone, and ethyl cellulose. Examples include resin. 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 ink preparation 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, tetrahydrofuran,
Examples include ethers such as dioxane, and organic solvents such as N,N-dimethylformamide and N-methylpyrrolidone. The base film used to apply ink for the production of transfer sheets includes condenser paper, thin paper such as glassine paper, polyester, polyamide,
Plastic films with good heat resistance such as polyimide are suitable, and their thickness may range from 3 to 50 μm. The ink can be applied to the base film using a reverse roll coater, gravure coater, rod coater, air doctor coater, etc., and the thickness of the ink coating layer after drying is in the range of 0.1 to 5 μm. All you have to do is apply it so that it is coated ("Coating Method" by Yuji Harasaki, published by Maki Shoten in 1979). Functions and Effects of the Invention The azo dye shown in [] above of the present invention has a clear magenta color, and is therefore suitable for obtaining full-color records with good color reproducibility by combining with appropriate yellow and cyan colors. and
Furthermore, since it is easily sublimed and has a large molecular extinction coefficient, it is possible to obtain high-speed recording with high color density without placing a large burden on the heat-sensitive head. Even more heat,
Since it is stable against light, moisture, chemicals, etc., it does not undergo thermal decomposition during transfer recording, and the resulting 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 specifically described below with reference to Examples, but these Examples are not intended to limit the present invention. Example 1 a Preparation of ink Azo dye of the present invention 10g Cellulose acetate ^* 10g Methyl ethyl ketone 80g Total 100g *Manufactured by Daicel Chemical Industries, Ltd., L-30 A mixture having the above composition was treated with a paint conditioner for 10 minutes to prepare an ink. The pigment and resin were completely dissolved, making it possible to obtain an ink with a uniform solution. b Preparation of transfer sheet Apply the above ink using a bar coater (RK Print
Coat Instruments Co., Ltd. No. 1) was applied onto a polyimide film (thickness: 15 μm) and air-dried to obtain a transfer sheet. c. Transfer Recording The ink coated surface of the above transfer sheet was overlapped with the recording medium and recording was carried out using a thermal head under the following conditions, and it was possible to obtain a record of a clear magenta color with a uniform color density of 1.15. Recording conditions Linear density of main scanning and sub-scanning: 4 dots/mm Recording power: 0.6 W/dot head heating time: 10 msec The recording material is made of 34% by weight saturated polyester.
10g of aqueous dispersion (manufactured by Toyobo Co., Ltd., Vylonal MD-1200, trade name) and silica (manufactured by Nippon Silica Kogyo Co., Ltd., Nipsil E220A, trade name)
It was produced by mixing 1 g of the solution, applying it to high-quality paper (200 μm thick) using a bar coater (manufactured by RK Print Coat Instruments, No. 3), and drying it. Color density was measured using a densitometer RD-514 model (filter: Ratten No. 58) manufactured by Macbeth, USA.
Measured using 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 63±2°C), and there was almost no discoloration or fading after 40 hours of irradiation.
Furthermore, the transfer sheet and recording were stable against heat and moisture, and had excellent storage stability in the dark. Example 2 The dyes shown in Table 1 were used instead of the dyes used in Example 1, and ink preparation, transfer sheet production, and transfer recording were carried out in the same manner as in Example 1. As a result, the results were as shown in Table 1. It was possible to obtain a clear magenta color record with the color density shown. Lightfastness test of the obtained recording and transfer sheet
The results of the dark storage stability test of the records were good.

【table】

【table】

[Table] Example 3 Ink was prepared using the azo dye of the present invention used in Example 1 with the following composition: 10 g of ethyl cellulose (manufactured by Hercules), 10 g of methyl ethyl ketone, 80 g of total 100 g. As a result of preparing a transfer sheet and performing transfer recording in the same manner as in Example 1, it was possible to obtain a record with a clear magenta color, a color density of 1.15, and good storage stability and light fastness. did it.

Claims (1)

[Claims] 1. General formula [] (In the formula, R is a hydrogen atom, a C ₁ to C ₈ alkyl group,
Represents a _C1 - _C8 alkoxy group, a _C3 - _C8 alkoxyalkyl group, or a halogen atom, and X is a methyl group, methoxy group, formylamino group, a _C1 - _C8 alkylcarbonylamino group, or a _C1 -C8 alkoxyalkyl group. represents a C ₈ alkylsulfonylamino group or a C ₁ to _{C 8} alkoxycarbonylamino group; Y represents a hydrogen atom; a C ₁ to _{C 4} alkoxy group; a methyl group; or a halogen atom; R ¹ and R ² represent Allyl group, _C1 - _C8 alkyl group, _C3 - _C8 alkoxyalkyl group,
(representing an aralkyl group or a hydroxyalkyl group) Azo dye for thermal transfer recording. 2. In the azo dye for thermal transfer recording according to claim 1, R represents a hydrogen atom, a methyl group, a methoxy group, a chlorine atom, or a bromine atom, and R ¹ and
R ² represents a C ₁ to C ₈ alkyl group, X is a methyl group,
_C1 - _C4 alkylcarbonylamino group, _C1 - _C4
represents an alkylsulfonylamino group, and Y
A dye in which is represented by a hydrogen atom. 3. A heat-sensitive transfer sheet comprising a coloring material layer containing an azo dye represented by the following general formula [] on a base film. General formula [] (In the formula, R is a hydrogen atom, a C ₁ to C ₈ alkyl group,
Represents a _C1 - _C8 alkoxy group, a _C3 - _C8 alkoxyalkyl group, or a halogen atom, and X is a methyl group, methoxy group, formylamino group, a _C1 - _C8 alkylcarbonylamino group, or a _C1 -C8 alkoxyalkyl group. represents a C ₈ alkylsulfonylamino group or a C ₁ to _{C 8} alkoxycarbonylamino group; Y represents a hydrogen atom; a C ₁ to _{C 4} alkoxy group; a methyl group; or a halogen atom; R ¹ and R ² represent Allyl group, _C1 - _C8 alkyl group, _C3 - _C8 alkoxyalkyl group,
(represents an aralkyl group, a hydroxyalkyl group).