JPH05236B2 - - 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 dye. 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 satisfy 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 light, moisture, chemicals, etc. Easy to synthesize. Excellent ink suitability. An object of the present invention is to provide a yellow dye that satisfies the above conditions and a heat-sensitive transfer sheet using the yellow dye. Structure of the invention A Means for solving the problem The present invention is based on the general formula [] (In the formula, X represents a hydrogen atom, a methyl group, or a chlorine atom, and R represents a C ₃ to _{C 8} alkoxyalkyl group,
_C5 - _C8 alkoxyalkoxyalkyl group, _C3
~ _C8 acyloxyalkyl group or _C3 ~ _C8 alkoxycarbonylalkyl group, R' is
(represents a C ₁ to C ₈ substituted or unsubstituted alkyl group)
The gist of the dye for thermal transfer is shown in the following. The dye of the present invention represented by the above general formula [] can be prepared using the following general formula [] by a known method, for example. (wherein, X, R, and R' are the same as defined above) is formylated by Vilsmeier-Haack reaction to form the following general formula [] It can be produced by obtaining an aldehyde represented by the formula (wherein X, R and R' are the same as defined above) and then condensing it with malononitrile. When applying the dye of the present invention to this recording method, the ink is prepared by dissolving or dispersing the dye in a medium together with a binder in the form of fine particles, and the ink is applied onto a base film and dried. It is necessary to produce a heat-sensitive transfer sheet for another purpose. 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 organic solvent-soluble resins, they can be used 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. The thickness of the ink coating layer after drying is in the range of 0.1 to 5 μm. (Coating method, written by Yuji Harasaki, published by Maki Shoten, 1979). Effects and Effects of the Invention The dye shown in [] above of the present invention can be said to be a styryl dye due to its structure, and
Because it has a clear yellow color, it is suitable for obtaining full-color records with good color reproducibility by combining it with appropriate magenta and cyan colors.It also sublimes easily and has a large molecular extinction coefficient, making it heat-sensitive. Records with high color density can be obtained at high speed without placing a large burden on the head. Furthermore, since it is stable against heat, 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 explained below with reference to Examples, but these Examples are not intended to limit the present invention. Example 1 a Preparation of ink The above pigment 10g Polysulfone resin ^* 10g Chlorobenzene 80g Total 100g *Yudel P-1700 (trade name) manufactured by Nissan Chemical Industries, Ltd. A mixture of the above composition was treated with a paint conditioner for 10 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 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. Even after the ink dried, the dye did not crystallize on the sheet, and it was possible to obtain a transfer sheet on which the dye was evenly coated. c. Transfer Recording The ink coated surface of the above transfer sheet was placed on the recording medium and recording was performed using a thermal head under the following conditions, and it was possible to obtain a clear yellow recording with a uniform color density of 1.0. Recording conditions Main scanning and sub-scanning linear density: 4 dots/mm Recording power: 0.6 W/dot Head heating time: 10 msec The recording material is 34% by weight saturated polyester.
10g of aqueous dispersion (manufactured by Toyobo Co., Ltd., Binalol MP-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. 47) manufactured by Macbeth, USA.
Measured using A light resistance test of the obtained records was conducted using a carbon arc fade meter (manufactured by Suga Test Instruments Co., Ltd.) (black panel temperature 63±2°C).
There was almost no deterioration after 40 hours of irradiation. The dye used here is N-ethyl-N-
It is obtained by formylating (β-methoxyethyl)-m-toluidine with phosphorus oxychloride in N,N-dimethylformamide according to a conventional method, and condensing the obtained formyl compound with malononitrile according to a conventional method. The melting point is 106-107℃, and the maximum absorption value of the absorption spectrum of chloroform solution is 446nm.
It was hot. 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. A clear yellow record with the color density shown in the table could be obtained.

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[Table] *Measured values in chloroform

Claims (1)

[Claims] 1. General formula [] (In the formula, X represents a hydrogen atom, a methyl group, or a chlorine atom, and R represents a C ₃ to _{C 8} alkoxyalkyl group,
_C5 - _C8 alkoxyalkoxyalkyl group, _C3
~ _C8 acyloxyalkyl group or _C3 ~ _C8 alkoxycarbonylalkyl group, R' is
(represents a C ₁ to C ₈ substituted or unsubstituted alkyl group)
A dye for thermal transfer indicated by . 2. In the thermal transfer recording dye according to claim 1, R' is a β-cyanoethyl group, a β-chloroethyl group, a _C2 to _C4 hydroxyalkyl group,
_C1 - _C8 alkyl group, _C3 - _C8 alkoxyalkyl group, phenoxyethyl group, _C5 - _C6 alkoxyalkoxyalkyl group, _C3 - _C8 acyloxyalkyl group, _C3 - _C8 alkoxy A dye represented by a carbonyl alkyl group, an allyl group, a benzyl group, a β-phenylethyl group, or a tetrahydrofurfuryl group. 3 General formula [] (In the formula, X represents a hydrogen atom, a methyl group, or a chlorine atom, and R represents a C ₃ to _{C 8} alkoxyalkyl group,
_C5 - _C8 alkoxyalkoxyalkyl group, _C3
~ _C8 acyloxyalkyl group or _C3 ~ _C8 alkoxycarbonylalkyl group, R' is
(represents a C ₁ to C ₈ substituted or unsubstituted alkyl group)
A heat-sensitive transfer sheet characterized by using a dye represented by: