JPH09207461A - Azo dye for thermosensitive transfer recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermosensitive transfer recording azo dye which satisfies all the conditions required for sublimable thermosensitive recording by using a compound represented by a specific formula as the azo which is easily sublimated by the operating conditions of a thermal recording head and stable for heat, light, moisture and chemicals without thermally decomposing. SOLUTION: As magenta dye used for a thermosensitive transfer recording system, azo dye represented by a formula (R is hydrogen atom, 1-8C alkyl group, 1-8C alkoxy group, 3-8C alkoxyalkyl group, or halogen atom, X is methoxy group or formylamino group, 1-8C alkylcarbonylamino group, 1-8C alkylsulfonylamino group, or 1-8C alkoxycarboxylamino group, Y is hydrogen atom, 1-4 alkoxy group, etc., R<1> , R<2> are aryl group, 1-8C alkyl group, or 3-8C alkoxyalkyl group). Thus, recording with excellent uniformity and color density can be performed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a dye used for sublimation type thermal transfer recording.

[0002]

2. Description of the Related Art Hitherto, there has been a demand for a technology for color recording of a facsimile printer, a copying machine, a television image or the like, and a color recording technology using electrophotography, ink jet, thermal transfer, and the like has been studied. The thermal transfer recording method is considered to be more advantageous than other methods because the maintenance and operation of the apparatus are easy and the apparatus and consumables are inexpensive. The thermal transfer system includes a base film, a base film and a transfer sheet having a heat-fusible ink layer formed thereon, which is heated by a thermal head to melt the ink and transfer-record on 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 transfer recording is performed on a recording medium.
The sublimation method can control the dye sublimation transfer amount by changing the energy applied to the thermal head.
Gradation recording becomes easy, which is considered to be particularly advantageous for full-color recording.

[0003]

When a dye is applied to this recording system, the dye must meet the following conditions. Easily sublimate under the operating conditions of the thermal recording head. Do not decompose under the operating conditions of the thermal recording head. Having a favorable hue in color reproduction. Large molecular extinction coefficient. Stable against heat, light, moisture, chemicals, etc. Easy synthesis. Excellent ink suitability. An object of the present invention is to provide a magenta dye satisfying all the above conditions.

[0004]

That is, the present invention provides the following general formula [I]:

[0005]

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(Wherein R represents a hydrogen atom, a C _{1 to} C ₈ alkyl group, a C _{1 to} C ₈ alkoxy group, a C _{3 to} C ₈ alkoxyalkyl group, a halogen atom, and X represents a methoxy group, A formylamino group, a C ₁ -C ₈ alkylcarbonylamino group, a C ₁ -C ₈ alkylsulfonylamino group, a C ₁ -C ₈ alkoxycarbonylamino group, and Y represents a hydrogen atom, C ₁ -C ₄ An alkoxy group of
It represents a methyl group or a halogen atom, and R ¹ and R ² represent an allyl group, a C _{1 to} C ₈ alkyl group, a C _{3 to} C ₈ alkoxyalkyl group, an aralkyl group or a hydroxyalkyl group. ) Is the gist of the azo dye for heat-sensitive transfer recording. As a method for producing these dyes of the present invention, for example, the following general formula [II]

[0007]

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An aniline represented by the formula (wherein R is the same as the above definition) is diazotized by a conventional method to give the following general formula [II
I]

[0009]

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## STR1 ## wherein X, Y, R ¹ and R ² are the same as defined above, and are obtained by coupling with an aniline represented by the following general formula [IV]

[0011]

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It can be obtained by reacting an azo compound represented by the formula (wherein R, X, Y, R ¹ and R ² are the same as defined above) with copper cyanide in a polar solvent.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Among the above-mentioned azo dyes of the present invention, X is preferably a C ₁ -C ₄ alkylcarbonylamino group or a C ₁ -C ₄ alkylsulfonylamino group, Particularly preferably, R in the above formula [I] represents a hydrogen atom, a methyl group, a methoxy group, a chlorine atom or a bromine atom, and R ¹ and R ² are C ₁ to
Examples thereof include a dye having a C ₈ alkyl group, X being a C _{1 to} C ₄ alkylcarbonylamino group, a C _{1 to} C ₄ alkylsulfonylamino group, and Y being a hydrogen atom. When the dye of the present invention is applied to a thermal transfer recording system, an ink is prepared by dissolving the dye in a medium or dispersing it in a fine particle form together with a binder, and the ink is coated on a base film and dried to transfer recording. Create a sheet for use.

As the binder for the ink preparation, water-soluble resins such as cellulose-based, acrylic acid-based and starch-based resins, organic resins such as acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, polyether sulfone and ethyl cellulose are used. Examples thereof include soluble resins. In the case of an organic solvent-soluble resin, it can be used not only as an organic solvent solution but also as an aqueous dispersion.

As a medium for preparing the ink, in addition to water, alcohols such as methyl alcohol, isopropyl alcohol and isobutyl alcohol, cellosolves such as methyl cellosolve and ethyl cellosolve, toluene,
Aromatic compounds such as xylene and chlorobenzene, esters such as ethyl acetate and butyl acetate, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, chlorinated solvents such as methylene chloride, chloroform and trichloroethylene, tetrahydrofuran, dioxane, etc. Organic solvents such as ethers, N, N-dimethylformamide, N-methylpyrrolidone and the like can be mentioned.

As the base film to which the ink is applied for preparing the transfer recording sheet, thin film such as condenser paper and glassine paper, and plastic film having good heat resistance such as polyester, polyamide and polyimide are suitable. However, their thickness is 3 to 50 μm.
Range. As a method of applying the ink to the base film, a reverse roll coater, a gravure coater, a rod coater, an air doctor coater or the like can be used, and the thickness of the ink application layer is 0.1 to 5 μm after drying. The coating can be applied within the range (Yuji Harasaki, Maki Shoten, 1979, "Coating method").

[0017]

EXAMPLES The present invention will be specifically described below with reference to examples, but the examples do not limit the present invention. Example 1 a) Preparation of ink

[0018]

[Chemical 6]

[0019] * L-30 manufactured by Daicel Chemical Industries, Ltd. The mixture having the above composition was treated with a paint conditioner for 10 minutes to prepare an ink. The dye and resin were completely dissolved, and an ink having a uniform solution could be obtained.

B) Preparation of transfer recording sheet The above ink was applied to a bar coater (RK Print Co).
No. manufactured by at Instruments. 1) was applied onto a polyimide film (thickness of 15 μm) and then naturally dried to obtain a transfer recording sheet.

C) Transfer recording The ink-coated surface of the transfer recording sheet is superposed on the recording medium and a thermal head is used to record under the following conditions to obtain a record with a clear magenta color and a uniform color density of 1.15. I was able to. Recording conditions Linear density in main scanning and sub scanning: 4 dots / mm Recording power: 0.6 W / dot Head heating time: 10 msec

The recording medium is saturated polyester 34.
A liquid prepared by mixing 10 g of a weight% aqueous dispersion (manufactured by Toyobo Co., Ltd., Bayronal MD-1200, trade name) and 1 g of silica (manufactured by Nippon Silica Kogyo Co., Ltd., Nipsil E220A, trade name) was used.
Bar coater (RK Print Coat I)
nstruments, No. It is manufactured by coating using 3) and then drying.

The color density is densitometer RD-514 (filter: Ratten No.
58). A light resistance test of the obtained record was performed using a carbon arc fade meter (manufactured by Suga Test Instruments Co., Ltd.) (black panel temperature 63 ± 2 ° C.).
However, there was almost no discoloration after 40 hours of irradiation.
Further, the transfer recording sheet and the recording were stable against heat and humidity and had excellent storage stability in the dark.

Example 2 In place of the dyes used in Example 1, the dyes shown in Table 1 were used, and ink was prepared, a transfer recording sheet was prepared, and transfer recording was carried out in the same manner as in Example 1. As a result, It was possible to obtain clear magenta recordings with the color densities shown in Table 1, respectively. The results of the light fastness test of the obtained record and the darkness storage stability test of the transfer recording sheet / recorded product were good.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

[Table 4]

[0029]

[Table 5]

Example 3 The composition of the azo dye of the present invention used in Example 1 was as follows: Dye (same as in Example 1) 10 g Ethyl cellulose (manufactured by Hercules) 10 g Methyl ethyl ketone 80 g ────────── ─────────────────────── A transfer recording sheet was prepared in the same manner as in Example 1 except that the total amount of ink was 100 g. As a result of the transfer recording, it was possible to obtain a recording having a clear magenta color, a color density of 1.15, and good storage stability and light fastness.

[0031]

Since the azo dye represented by the above [I] of the present invention has a vivid magenta color, it can be combined with an appropriate yellow color and cyan color to obtain a full color record having good color reproducibility. It is suitable, easy to sublimate, and has a large molecular extinction coefficient, so that high-density recording with high color density can be obtained without imposing a heavy load on the thermal head. Further, since it is stable against heat, light, moisture, chemicals, etc., it does not undergo thermal decomposition during transfer recording, and the obtained recording has excellent storage stability. Further, since the dye of the present invention has good solubility in an organic solvent and dispersibility in water, it is easy to prepare a highly concentrated ink that is uniformly dissolved or dispersed, and by using these inks, It is possible to obtain a transfer recording sheet on which the dye is uniformly applied at a high concentration. Therefore, by using these transfer recording sheets, it is possible to obtain recording with good uniformity and color density.

Claims (3)

[Claims] 1. A compound of the general formula [I] (In the formula, R represents a hydrogen atom, a C _{1 to} C ₈ alkyl group, C ₁
Alkoxy group -C _8, an alkoxyalkyl group C ₃ -C _8, a halogen atom, X is a methoxy group, formylamino group, alkylcarbonylamino group of C ₁ -C _8, alkylsulfonyl C ₁ -C ₈ Amino group, C ₁ ~
Represents a C ₈ alkoxycarbonylamino group, and Y represents a hydrogen atom, a C ₁ -C ₄ alkoxy group, a methyl group,
Represents a halogen atom, R ¹ and R ² are allyl groups, C ₁ to
It represents a C ₈ alkyl group, a C ₃ -C ₈ alkoxyalkyl group, an aralkyl group, or a hydroxyalkyl group. )
An azo dye for heat-sensitive transfer recording shown by. 2. The azo dye for thermal transfer recording according to claim _{1, wherein} X is a C ₁ -C ₄ alkylcarbonylamino group. 3. The azo dye for thermal transfer recording according to claim _{1, wherein} X is a C ₁ -C ₄ alkylsulfonylamino group.