JPH05233B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an anthraquinone dye 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, 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 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. The object of the present invention is to provide a magenta dye that satisfies the above-mentioned requirements for a dye used in the heat-sensitive recording method. That is, the present invention provides the following general formula [] (In the formula, -X- represents -O- or -S-,
-A- is a linear or branched alkylene group, alkylene-O-alkylene group, alkylene-S-alkylene group,

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The gist thereof is a heat-sensitive transfer sheet characterized by having an anthraquinone-based heat-sensitive transfer recording dye represented by the following formula and a coloring material layer containing the dye on a substrate. Examples of -A- represented by the general formula [] include those shown in Table 1 below.

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[Table] Particularly preferable -A- is -CH ₂ CH ₂ -,

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[Formula], -CH ₂ CH ₂ OCH ₂ CH ₂ -, -CH ₂ CH ₂ SCH ₂ CH ₂ -. As a method for producing a thermal transfer recording ink using the dye of the present invention, the dye is mixed with a suitable resin solvent,
It may be mixed with water or the like to form 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,
Oil-based resins such as rosin-based, phenol-based, xylene-based, petroleum-based, polysulfone-based, vinyl-based, polyamide-based, alkyd-based, nitrocellulose-based, alkylcellulose, and alkylcelluloses may be used in ordinary printing inks. Alternatively, water-based resins such as maleic acid-based, acrylic-acid-based, gasein, silicone, and glue can be used.
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, and xylene, ethyl acetate, butyl acetate, etc. esters, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, hydrocarbons such as ligroin, cyclohexane, and kerosene, and dimethylformamide. However, when using an aqueous resin, water or water and the above solvents can be used. Can also be used in combination. 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 medium, but in order to improve the color development of the dye, it is common to use a resin that has good compatibility with the dye, or a resin to which acidic fine particles such as silica gel are added. By using coated or impregnated paper, laminated with resin film, or special processed paper treated with acetylation, good recording with excellent image stability under high temperature and high humidity conditions can be achieved. . 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 magenta color, for example, the structural formula is as follows: The yellow pigment represented by and the structural formula below Full color can be obtained by combining with cyan dye represented by EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to the following Examples. Example 1 Production of dye A mixture of 130 g of neopentyl glycol and 6 g of potassium hydroxide was heated at 110 to 120°C under a weak nitrogen stream.
The mixture was stirred for 1 hour. Then, at the same temperature, the following structural formula After adding 30 g of anthraquinone compound shown by and stirring at 150 to 160°C for 2 hours, leave to cool to room temperature, add methanol and stir, and after filtration,
Washed with methanol, then water and dried in a vacuum dryer at 40-50°C to give 25g of dark red powder.
I got it. When recrystallized using n-butanol, 20 g of a dye (dark red needle-like crystals) represented by the following structural formula was obtained. The melting point of this dye was 217-220°C, and the mass spectrum showed a parent ion peak of m/e=325. Furthermore, the maximum absorption wavelength, λmax, of the visible absorption spectrum in chloroform was 513 nm. Preparation method for thermal transfer recording ink 2g of the pigment obtained in the above section) Ethyl cellulose 8g Isopropanol 90g Total 100g The pigment mixture having the above composition was mixed with a paint conditioner using glass beads for about 30 minutes to form the ink. was prepared. How to make a transfer sheet: The above ink was applied to condenser paper (10 μm) using a gravure proofing machine (plate depth: 30 μm). How to make an image receiving paper: Aqueous dispersion of 34% by weight of saturated polyester (manufactured by Toyobo Co., Ltd., Vylonal MD- 1200) 10g
and silica gel (Nipsil E220A, Nippon Silica Manufacturing)
Mix 1 g of the prepared paint and place it on high-quality paper (thickness
200μm) with a bar coater (RK Print Coat)
No. 1) manufactured by Instruments Inc. Transfer Recording Method The ink-coated surface of the transfer sheet was placed on the paint-coated surface of the image receiving paper, and thermal transfer recording was performed using a thermal head having a 250Ω heating resistor at a density of 4 dots/m/m to achieve a color density of 0.95. I got a magenta record. 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 RD-514 model manufactured by Macbeth (Filter: Ratten No. 58).
Measured using Color density was calculated using the following formula. Color density = og ₁₀ (Io/I) Io: 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 ( The experiment was conducted using a black panel (manufactured by Suga Test Instruments Co., Ltd.) at a black panel temperature of 63±2℃.
There was almost no discoloration after 40 hours of irradiation, and the image stability was excellent even under high temperature and high humidity conditions. Example 2 Instead of the dye used in Example 1, the following formula Using 2g of the dye represented by , the ink was prepared, a transfer sheet was created, and the transfer recording was performed in the same manner as in Example 1. The magenta color with a color density of 0.9 had excellent light fastness, and it was resistant to high temperatures and high humidity. A record of excellent stability was obtained. The above dye was prepared in the same manner as the dye of Example 1, using 110 g of 1,3-propylene glycol instead of neopentyl glycol. The dye obtained had a melting point of 240° C. (decomposed), a λmax in chloroform of 514 nm, and a parent ion peak of m/e=313 in the mass spectrum. Example 3 Ink preparation method The above pigment 2g Acrylic acid resin (Dyanol BR-107 product name manufactured by Mitsubishi Rayon Co., Ltd.) 8g Ethanol 45g Water 45g Total 100g Add the pigment mixture of the above composition using glass beads and apply it to a paint conditioner for about 30 minutes.
The ink was prepared by mixing for a minute. Method for creating a transfer sheet The above ink was applied to glassine paper (10 μm) using the gravure proofing machine used in Example 1. Transfer recording method The ink-coated surface of the above transfer sheet was placed on high-quality paper laminated with polyester film (10 μm), and using the thermal recording head used in Example 1,
As a result of recording under similar conditions, a magenta color with a color density of 0.85 had excellent light fastness and excellent stability under high temperature and high humidity conditions. The above dye was produced in the same manner as the dye of Example 1, using 95 g of ethylene glycol instead of neopentyl glycol. The resulting dye has a melting point of 230°C (decomposition),
The λmax in chloroform was 514 nm, and the mass spectrum showed a parent ion peak of m/e=283. Example 4 The following formula was used instead of the dye used in Example 1. Using 2 g of the dye represented by , the ink was adjusted, a transfer sheet was prepared, and transfer recording was performed in the same manner as in Example 1, resulting in a magenta color with a color density of 0.80, excellent light fastness, and stability under high temperature and high humidity. Obtained an excellent record. The above dye was produced in the same manner as the dye of Example 1, using 152 g of diethylene glycol instead of neopentyl glycol. The resulting dye had a melting point of 230°C (decomposed) and a λmax of 514 nm in chloroform. Example 5 Using 2 g of the pigment shown in Table 2, ink adjustment, transfer sheet and image receiving paper were prepared in the same manner as in Example 1, and then transfer recording was performed in the same manner as in Example 1. A magenta color record with the color density shown in Table 2 was obtained. All of these records were tested for light resistance in the same manner as in Example 1, and the records showed almost no discoloration and had excellent image stability under high temperature and high humidity.

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Claims (1)

[Claims] 1. General formula [] (In the formula, -X- represents -O- or -S-,
-A- represents a linear or branched alkylene group, alkylene-O-alkylene group, alkylene-S-alkylene group, [formula] [formula] [formula] [formula]) Dye for thermal transfer recording. 2. A heat-sensitive transfer sheet characterized by having a coloring material layer containing an anthraquinone dye represented by the following general formula [] on a base material. (In the formula, -X- represents -O- or -S-,
-A- represents a linear or branched alkylene group, alkylene-O-alkylene group, alkylene-S-alkylene group, [formula] [formula] [formula] [formula])