JPH0461797B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a styryl dye for thermal transfer recording and a thermal transfer sheet using the dye. Currently, a dye sublimation thermal transfer recording method has been proposed as a method for obtaining color hard copies from televisions, CRT color displays, color facsimile machines, magnetic cameras, etc. In this method, a transfer sheet coated with a sublimable dye is heated with a heat-sensitive recording head to sublimate and transfer the dye to the recording medium to obtain color recording, but by adjusting the energy applied to the heat-sensitive head, the dye Since the amount of sublimation can be controlled, it is easy to express gradation, and compared to other recording methods, it is especially advantageous for obtaining full-color hard copies. By the way, the dye used in this recording method must meet the following conditions. Easily sublimes under the operating conditions of a thermal recording head. Does not thermally decompose under the operating conditions of a thermal recording head. Has a favorable hue for color reproduction. Has a large molecular extinction coefficient. Stable against light, moisture, chemicals, etc. Ease of Synthesis The object of the present invention is to provide a yellow dye that satisfies the requirements for the dye used in the above-mentioned heat-sensitive recording method, particularly. That is, the present invention provides the following general formula [I] (In the formula, R is an allyl group, a methyl group, an ethyl group,
Represents a linear or branched propyl group or butyl group, and A is -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂
CH ₂ O-, -CH ₂ CH ₂ OCH ₂ -, -CH ₂ CH ₂ OCH ₂
A heat-sensitive transfer sheet characterized by having a styryl dye for heat-sensitive transfer recording represented by (representing CH ₂ -) and a coloring material layer containing a styryl dye represented by the above general formula [I] on a base material. This is a summary. The dye of the present invention can be prepared according to known methods, for example,
General formula below [] (In the formula, R and A are the same as defined above) is reacted with malonitrile in an organic solvent such as ethanol or N,N-dimethylformamide, and after the reaction, the precipitated target product is filtered. can be easily obtained. If the target product does not precipitate after the reaction, the target product can be precipitated by adding a solvent or water that has low solubility to the target product. Furthermore, the target product can be purified by conventional means such as recrystallization or column chromatography, if necessary. As a method for producing a thermal transfer recording ink using the dye of the present invention, the dye may be mixed with a suitable resin, solvent, water, etc. to prepare the recording ink. In the thermal transfer method, the ink obtained above is applied onto a suitable base material to create a transfer sheet, the sheet is placed on the recording medium, and then heated and pressed from the back side of the sheet using a thermal recording head. In this way, the dye on the sheet is transferred onto the recording medium. As the resin for preparing the above ink,
Those used in ordinary printing inks may be used, such as oil-based resins such as rosin-based, phenol-based, xylene-based, petroleum-based, vinyl-based, polyamide-based, alkyd-based, nitrocellulose-based, alkyl cellulose, or maleic resins. Acid-based,
Water-based resins such as acrylic acid, casein, Sierra, and glue can be used. In addition, as a solvent for ink preparation, methanol, ethanol,
Alcohols such as propanol and butanol,
Carbonization of cellosolves such as methyl cellosolve and ethyl cellosolve, aromatics such as benzene, toluene, and xylene, esters such as ethyl acetate and butyl acetate, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and ligroin, cyclohexine, and kerosene. Hydrogens, dimethylformamide, etc. can be used, but when using an aqueous resin, water or a mixture of water and the above-mentioned solvents can also be used. Substrates for applying ink include condenser paper, thin paper such as glassine paper, polyester,
A plastic film having good heat resistance such as polyamide or polyimide is suitable, and the thickness of these substrates is suitably about 5 to 50 .mu.m in order to improve the efficiency of heat transfer from the heat-sensitive recording head to the dye. Plain paper can also be used as the recording material, but in order to improve the color development of the dye, it may be coated or impregnated with a resin that is compatible with the dye, or it may be laminated with a resin film. Good recording can be achieved by using paper or special processed paper that has been treated with acetylation. It is also possible to use films of various resins or synthetic papers made from them. Furthermore, by hot-pressing and laminating, for example, a polyester film on the transfer recording surface after transfer recording, it is possible to improve the color development of the dye and to stabilize the recording during storage. Since the dye of the present invention has a clear yellow color, for example, the structural formula is as follows: The magenta pigment represented by and the structural formula below Suitable for obtaining full color in combination with cyan pigment represented by It can also be used in combination with other yellow pigments. The above magenta dye can be easily produced by reacting tetracyanoethylene and N-butyl-N-hydroxyaniline. In addition, the above cyan dye is 1-amino-2
-Carboxy-4-methylaminoanthraquinone can be produced by reacting methanol in concentrated sulfuric acid. EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples. Example 1 Method for preparing ink for thermal transfer recording (Maximum absorption wavelength: 444 nm: Chloroform) (Melting point: 160-163°C) The above pigment: 2g Ethyl cellulose: 8g Isopropanol: 90g Total: 100g The pigment mixture having the above composition is mixed with a paint conditioner using glass beads for about 30 minutes to form the ink. was prepared. Method for creating a transfer sheet The above ink was applied to condenser paper (10 μm) using a gravure proofing machine (plate depth 30 μm). Method for making receiver paper Aqueous dispersion of 34% by weight saturated polyester (manufactured by Toyobo Co., Ltd., Vylonal MD-1200)
10g and calcium bicarbonate (Maruo Calcium Manufacturing,
Super 1500) A paint prepared by mixing 50g of 50% water slurry was applied to high-quality paper (thickness 200μm) using a bar coater (manufactured by RK Print Coat Instruments).
No. 5). Transfer recording method The ink-coated surface of the transfer sheet is placed on the paint-coated surface of the image-receiving paper, and thermal transfer recording is performed using a thermal head with a 250Ω heating resistor at a density of 4 dots/mm to produce a yellow color with a color density of 1.00. Obtained a record of. At this time, a voltage of 18V was applied to the heat-sensitive head for 6 milliseconds. The color density was measured using a densitometer model RD514 (filter: Ratten No. 47) manufactured by Macbeth, USA. Color density was calculated using the following formula. Color density = log ₁₀ (I ₀ /I) I ₀ : Intensity of reflected light from standard white reflector I : Intensity of reflected light from test object In addition, the light resistance test of the obtained records was performed using carbon arc The test was carried out using a fade meter (manufactured by Suga Test Instruments Co., Ltd.) at a black panel temperature of 63±2°C, and there was almost no discoloration after 40 hours of irradiation. Example 2 Using 2 g of the pigment shown in Table 1, ink was prepared, a transfer sheet and receiver paper were created, and transfer recording was performed in the same manner as in Example 1, and a yellow color with the color density shown in Table 1 was obtained. Obtained a record of. All of these records were tested for light resistance in the same manner as in Example 1, and in this test, the records obtained using the dye of the present invention showed almost no discoloration.

【table】

[Table] *The maximum absorption wavelength indicates the measured value in chloroform.

Claims (1)

[Claims] 1 General formula [I] (In the formula, R is an allyl group, a methyl group, an ethyl group,
Represents a linear or branched propyl group or butyl group, and A is -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂
CH ₂ O-, -CH ₂ CH ₂ OCH ₂ -, -CH ₂ CH ₂ OCH ₂
A styryl dye for thermal transfer recording, which is represented by CH ₂ -. 2 General formula [I] on the base material (In the formula, R is an allyl group, a methyl group, an ethyl group,
Represents a linear or branched propyl group or butyl group, and A is -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂
CH ₂ O-, -CH ₂ CH ₂ OCH ₂ -, -CH ₂ CH ₂ OCH ₂
1. A heat-sensitive transfer sheet comprising a coloring material layer containing a styryl dye (representing CH ₂ -).