JPH056520B2 - - Google Patents

Description

[Detailed description of the invention]

Object of the Invention (a) Field of Industrial Application The present invention relates to an indophenol dye for thermal transfer recording and a sheet for thermal transfer recording. 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. Since the amount of sublimation can be controlled, gradation expression is easy. Therefore, this method is considered to be a particularly advantageous method for obtaining color hard copies compared to other recording methods. (b) Conventional technology Traditionally, indophenol dyes have the following structural formula: Indophenol pigments represented by (J.PRAKT.Chem., 320 (5), 705-714) are known. (c) Problems to be Solved by the Invention However, when the above-mentioned conventional indophenol dyes are used as dyes for thermal transfer recording, improvements in heat resistance, molecular extinction coefficient, and storage stability have been desired. (d) Purpose The present invention provides a cyan indophenol which has high heat resistance under the operating conditions of a thermal recording head, has a large molecular extinction coefficient, and has excellent storage stability against light, moisture, chemicals, temperature, etc. The object of the present invention is to provide a dye and a heat-sensitive transfer recording sheet using the same. Structure of the invention (a) Means for solving the problem The present invention is based on the general formula [] (In the formula, R ¹ , R ² and R ³ are an alkyl group, an aralkyl group, an alkenyl group, an aryl group, a cyclohexyl group, a halogenoalkyl group, an alkoxyalkyl group, an alkoxyalkoxyalkyl group, a hydroxyalkyl group, a hydroxyalkoxyalkyl group, Hydroxyalkylthioalkyl group, cyanoalkyl group, tetrahydrofurfuryl group, aralkyloxyalkyl group, aryloxyalkyl group, alkenyloxyalkyl group, tetrahydrofurfuryloxyalkyl group, alkoxycarbonylalkyl group, alkylcarbonyloxyalkyl group or alkoxycarbonyloxy represents an alkyl group, X represents a hydrogen atom, a methyl group, a chlorine atom, a bromine atom or an acylamino group,

【ceremony

[expression] or

The gist of the invention is an indophenol-based thermal transfer recording dye and a thermal transfer recording sheet represented by the following formula. As a method for producing the dye of the present invention represented by the above general formula [], the following general formula [] (wherein R ¹ is the same as defined above,

[Formula] Haha

[expression] or

The compound represented by [Formula]) and the following general formula [] (In the formula, X, R ² and R ³ are the same as defined above.) It can be produced by heating an aniline represented by the following formula in the presence of silver nitrate. R ¹ , R ² and R ³ represented by the general formula [] include a methyl group, an ethyl group, an n-propyl group,
i-propyl group, n-butyl group, i-butyl group,
Alkyl groups such as n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group; aralkyl group such as benzyl group, β-phenethyl group; allyl group, 2-methylallyl group,
Alkenyl groups such as 2-chloroallyl group, 2-bromoallyl group, crotyl group, 3-phenylallyl group; phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, p-chlorophenyl group, p
-bromophenyl group, p-methoxyphenyl group,
Aryl groups such as p-trifluoromethylphenyl group, p-nitrophenyl group, m-chlorophenyl group; cyclohexyl group; alkoxy such as methoxyethyl group, ethoxyethyl group, propoxyethyl group, butoxyethyl group, γ-methoxybutyl group Alkyl group; alkoxyalkoxyalkyl group such as methoxyethoxyethyl group, ethoxyethoxyethyl group, propoxyethoxyethyl group; hydroxyalkyl group such as hydroxyethyl group, β-hydroxypropyl group, β-hydroxybutyl group; chloroethyl group, chloropropyl group , bromoethyl group, iodoethyl group; cyanoalkyl group such as cyanomethyl group, cyanoethyl group, cyanopropyl group; tetrahydrofurfuryl group; alkenyloxyalkyl group such as allyloxyethyl group, 2-methylallyloxyethyl group; groups; aryloxyalkyl groups such as phenyloxyethyl group and p-chlorophenyloxyethyl group; aralkyloxyalkyl groups such as benzyloxyethyl group and phenethyloxyethyl group; methoxycarbonylethyl group, ethoxycarbonylethyl group, Alkoxycarbonylalkyl groups such as propoxycarbonylethyl group, methoxycarbonylmethyl group, ethoxycarbonylmethyl group; acetoxyethyl group, propionyloxyethyl group,
Alkylcarbonyloxyalkyl groups such as β-acetoxypropyl group and β-acetoxybutyl group;
Alkoxycarbonyloxyalkyl groups such as methoxycarbonyloxyethyl group and ethoxycarbonyloxyethyl group; Tetrahydrofurfuryloxyalkyl groups such as tetrahydrofurfuryloxyethyl group; Hydroxyalkoxyalkyl groups such as hydroxyethoxyethyl group and hydroxypropoxyethyl group; Examples include hydroxyethylthioethyl group, especially hydroxyalkylthioalkyl group. Examples of X include a hydrogen atom; a methyl group; a chlorine atom; a bromine atom; and an acylamino group such as an acetylamino group, a propionylamino group, and a benzoylamino group. Particularly preferable R ¹ , R ² and R ³ include a methyl group,
Ethyl group, benzyl group, phenethyl group, allyl group, phenyl group, m-tolyl group, p-chlorophenyl group, p-bromophenyl group, methoxyethyl group, ethoxyethyl group, hydroxyethyl group,
Examples include a cyanoethyl group and a tetrahydrofurfuryl group, and examples of X include a hydrogen atom, a methyl group, a chlorine atom, and an acetylamino group. 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 addition, as a thermal transfer method, the ink obtained above is applied onto a suitable base material to create a transfer sheet of the present invention, the sheet is placed on a recording medium, and then heated from the back side of the sheet with a thermal recording head. In this case, the dye on the sheet is transferred onto the recording medium. As the resin for preparing the above ink,
Those with a high melting point or softening point are suitable; specifically, phenolic resins, melamine resins, urethane resins, epoxy resins, silicone resins, urea resins, diallyl phthalate resins, alkyd resins, acetal resins, acrylic resins, methacrylic resins, Polyester resin, starch and its derivatives, cellulose resin, polyvinyl chloride, polyvinylidene chloride, fluororesin, chlorinated polyethylene, polyethylene, polypropylene, polystyrene, polyvinyl cetal, polyamide, polyvinyl alcohol, polycarbonate, polysulfone, polyether Sulfone, polyethylene terephthalate, polybutylene terephthalate, polyphenylene oxide, polyphenylene sulfide,
Polyethylene naphthalate, polyacrylonitrile, polyimide, polyamideimide, AS resin,
Examples include ABS resin. In addition, solvents for ink preparation include alcohols such as methanol, ethanol, propanol, and butanol, cellosolves such as methyl cellosolve and ethyl cellosolve, aromatics such as benzene, toluene, xylene, and chlorobenzene, ethyl acetate, and acetic acid. Examples include esters such as butyl, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, hydrocarbons such as ligroin, cyclohexane, and kerosene, and dimethylformamide.
When using an aqueous resin, water or a mixture of water and the above-mentioned solvents can 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 base materials 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. In addition, plain paper can 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 in some cases. By using materials added with inorganic particulate matter such as silica gel, materials laminated with resin films, or special processed paper treated with acetylation, they have excellent light resistance and storage stability under high temperature and high humidity conditions. Good records can be obtained. 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 cyan color, for example, the structural formula is as follows: The yellow pigment represented by and the structural formula below It is suitable for obtaining full color when combined with the magenta color pigment represented by . EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present Examples are not intended to limit the present invention. (b) Examples and effect examples 1 (a) Structure of dye The following structural formula 5.26g of the compound represented by and the following structural formula 5.24g of the compound represented by 50ml of ethanol
After stirring at room temperature, an aqueous solution of 3.4 g of silver nitrate dissolved in 15 ml of water was added dropwise. then
After adding 15 ml of 28% ammonia water, an aqueous solution of 10.5 g of silver nitrate dissolved in 10 ml of water was added dropwise, and the mixture was reacted at 50° C. for 2 hours. After the reaction is complete, extract with chloroform, distill off the solvent, and perform column purification with chloroform to obtain the following structural formula. 5.16 g of a purified indophenol pigment represented by was obtained. The melting point of the dye was 185-187°C, and the maximum absorption wavelength (chloroform) was 689 nm. (b) Preparation method of thermal transfer recording ink 2 g of the dye obtained in the above (a) 8 g of ethyl cellulose 90 g of isopropanol Total 100 g The dye mixture of the above composition was mixed with a paint conditioner using glass beads for about 30 minutes. The ink was prepared by: (c) 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). (d) Method for making image receiving paper Aqueous dispersion of 34% by weight saturated polyester (manufactured by Toyobo Co., Ltd., Vylonal MD-1200)
A paint prepared by mixing 10 g of silica gel and 5 g of silica gel (Nipsil E220A product name, manufactured by Nippon Silica Kogyo Co., Ltd.) was coated on high-quality paper (thickness 200 μm) using a bar coater (manufactured by RK Print Coat Instruments Co., Ltd.).
No. 5). (e) Transfer recording method Lay the ink-coated surface of the transfer sheet on the paint-coated surface of the image-receiving paper and apply the heating resistor at 4 dots/mm.
Thermal transfer recording was performed using a thermal head with a density of 0.75, and a cyan color recording with a color density of 0.75 was obtained.
At this time, the thermal head receives a power of 0.6W/dot.
10ms added. The color density is measured using a densitometer RD-514 model manufactured by Macbeth Co., Ltd. (filter: Ratten).
No. 25). Color density was calculated using the following formula. Color density = log10 (I ₀ /I) I ₀ : Intensity of reflected light from the standard white reflector I : Intensity of reflected light from the test object In addition, the light fastness test of the obtained record was performed using a xenon fade meter. (manufactured by Suga Test Instruments Co., Ltd.) at a black panel temperature of 63 ± 2°C.
There was almost no discoloration due to irradiation over time, and the image storage stability (bleeding and discoloration and fading) under high temperature and high humidity conditions was also good. 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 according to the method of Example 1, and cyan color recordings were made with the color densities shown in Table 1. I got it. All of these records were subjected to a light fastness test in the same manner as in Example 1, and the records showed almost no discoloration and had excellent image storage stability under high temperature and high humidity conditions. The maximum absorption wavelength of the dye was measured in chloroform.

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

Claims (1)

[Claims] 1. General formula [] (In the formula, R ¹ , R ² and R ³ are an alkyl group, an aralkyl group, an alkenyl group, an aryl group, a cyclohexyl group, a halogenoalkyl group, an alkoxyalkyl group, an alkoxyalkoxyalkyl group, a hydroxyalkyl group, a hydroxyalkoxyalkyl group, Hydroxyalkylthioalkyl group, cyanoalkyl group, tetrahydrofurfuryl group, aralkyloxyalkyl group, aryloxyalkyl group, alkenyloxyalkyl group, tetrahydrofurfuryloxyalkyl group, alkoxycarbonylalkyl group, alkylcarbonyloxyalkyl group or alkoxycarbonyloxy represents an alkyl group, X represents a hydrogen atom, a methyl group, a chlorine atom, a bromine atom or an acylamino group,
[Formula] represents [Formula] or [Formula]), an indophenol-based thermal transfer recording dye represented by: 2 General formula [] (In the formula, R ¹ , R ² and R ³ are an alkyl group, an aralkyl group, an alkenyl group, an aryl group, a cyclohexyl group, a halogenoalkyl group, an alkoxyalkyl group, an alkoxyalkoxyalkyl group, a hydroxyalkyl group, a hydroxyalkoxyalkyl group, Hydroxyalkylthioalkyl group, cyanoalkyl group, tetrahydrofurfuryl group, aralkyloxyalkyl group, aryloxyalkyl group, alkenyloxyalkyl group, tetrahydrofurfuryloxyalkyl group, alkoxycarbonylalkyl group, alkylcarbonyloxyalkyl group or alkoxycarbonyloxy represents an alkyl group, X represents a hydrogen atom, a methyl group, a chlorine atom, a bromine atom or an acylamino group,
[Formula] represents [Formula] or [Formula]), A thermal transfer recording sheet characterized by using an indophenol dye represented by the following.