JPH0515198B2 - - Google Patents

Description

[Detailed description of the invention]

Object of the Invention (a) Industrial Application Field The present invention relates to a thermal transfer material used for sublimation type thermal transfer recording. (b) Prior Art Currently, 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-fusible 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 a color material layer containing a sublimable dye is formed is heated by a thermal head to sublimate the dye, and then transferred and recorded onto the recording medium. By changing the energy, the amount of sublimation of the dye can be controlled, which facilitates gradation recording and is particularly advantageous for full-color recording. In order to obtain a cyan color record using sublimation type thermal transfer recording, it is sufficient to perform the transfer recording using a transfer material containing a cyan dye as the color material, but conventionally, cyan color transfer materials do not have enough cyan dye. There is no one with high performance, and there is a demand for its development. (c) Problems to be solved by the invention Conventional cyan transfer sheets using only the dyes represented by the above general formulas [] and [] had good sublimation properties and excellent fastness. but,
The following problems occurred in the preparation and color tone of the transfer sheet. In other words, the indoaniline dyes represented by the general formulas [] and [] dissolve relatively well in solvents and binders, but the dyes precipitate when creating highly concentrated inks or when the ratio with the binder is increased. It is not possible to produce a uniform transfer sheet. (d) Purpose The present invention enables the preparation of high-density ink, provides a transfer sheet coated with a pigment uniformly and at high concentration, and further provides a cyan-colored transfer record without image unevenness and scratch-free stains. The purpose is to provide a heat-sensitive transfer material that can Means for Solving the Problems The present invention provides a thermal transfer material having a coloring material layer on a support, in which the coloring material layer contains dyes represented by the general formulas [] and []. The gist is thermal transfer materials. (In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ represent a linear or branched C ₁ to C ₃ alkyl group) The cyan transfer sheet of the present invention is , can be obtained by blending the indoaniline dye represented by the general formula [] and the indoaniline dye represented by the general formula [] in an arbitrary ratio. The blending ratio of each dye is as shown in the general formula []
The pigment represented by the formula [] accounts for 5 to 95%, and the pigment represented by the general formula [] accounts for 95 to 5%.
Particularly preferred blending ratios include 30% to 70%, and 70% to 70%.
Each range of 30% can be mentioned. In order to produce a transfer sheet, an ink may be prepared by dissolving the above-mentioned blended dye together with a binder in a medium, and the ink may be applied onto a base film and dried. Binders for ink preparation include aqueous resins such as cellulose, acrylic, and starch resins, resins soluble in organic solvents such as acrylic resins, methacrylic resins, polystyrene, polycarbonate, polysulfone, polyethersulfone, and ethyl cellulose. can be mentioned. 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;
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, ethers such as tetrahydrofuran and dioxane, N,N-dimethyl Organic solvents such as formamide and N-methylpyrrolidone can be mentioned. The base film used to apply ink for the production of transfer sheets includes condenser paper, thin paper such as glassine paper, polyester, polyamide,
A plastic film with good heat resistance, such as polyimide, is suitable. Moreover, the thickness of the base film can be in the range of 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. (Yuji Harasaki, "Coating method")
(1979) Maki Shoten). Functions and Effects of the Invention The pigments represented by the general formulas [] and [] of the present invention have good solubility in organic solvents, so it is easy to prepare a uniformly dissolved and highly concentrated ink. By using this ink, it is possible to obtain a transfer sheet on which the dye is uniformly coated at a high concentration. Moreover, by using this transfer sheet, it is possible to obtain a cyan-colored transfer record with an even image and no scratches. The cyan transfer sheet of the present invention is easy to sublimate and has a color material layer containing dyes with matching sublimation properties, so it can quickly achieve color density without placing a large burden on the heat-sensitive head. You can get a high record of. 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. 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 Blending ratio Mixed pigment (1-1) (1-2) 7g (50%) 7g (50%) Polysulfone resin ^* 10g Chlorobenzene 50g Total 74g * Manufactured by Nissan Chemical Industries, Ltd., Udel P-
1700 (trade name) A mixture having 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 high concentration solution could be obtained. (b) Preparation of transfer sheet Transfer the above ink to a barcoder (RK Print).
When coated on a polyimide film (15 μm thick) using Coat Instruments Co., Ltd. (No. 1) and dried with hot air at 60°C, a uniformly coated transfer sheet was obtained with no pigment precipitation. did it. (c) Transfer recording The ink-applied surface of the above transfer sheet is placed over the recording medium and recorded using a thermal head under the following conditions, and it is possible to obtain a clear cyan color record with a uniform high color density of 1.80 without image unevenness. did it. 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 medium was an aqueous dispersion of 34% by weight saturated polyester (manufactured by Toyobo Co., Ltd., Vylonal MD-1200, trade name) 10g and silica (manufactured by Nippon Silica Kogyo Co., Ltd., Nipsil E220A,
Mix 1 g of product name) and apply the prepared solution to high-quality paper (200 μm thick) using a bar coater (RK Print Coat).
After application using No. 3 manufactured by Inetruments,
Produced by drying. Color density was measured using a densitometer RD-514 model manufactured by Macbeth Corporation in the United States (filter: Ratten No.
25). The light resistance test of the obtained record was performed using a carbon arc fade meter (manufactured by Suga Test Instruments Co., Ltd.).
It was carried out using a black panel at a temperature of 63±2°C, and there was almost no discoloration or fading after 40 hours of irradiation. Comparative Examples 1 and 2 Mixed pigments of Example 1 (1-1) and (1-2)
Instead of 14 g, 14 g of the dye (1-1) was used alone (Comparative Example 1), and 14 g of the dye (1-2)
was used alone (Comparative Example 2), and an ink was prepared in the same manner as in Example 1 except for the pigment. In each of the obtained inks, a portion of the pigment was not dissolved and remained undissolved. This ink was applied to a base film and dried, but significant precipitation of the dye was observed and an uneven transfer sheet was obtained. Then,
Transfer recording was performed using this transfer sheet, but
Only a cyan-colored transfer record with a lot of image unevenness and heavy scratches could be obtained. Example 2 In place of the blended pigments [(1-1) and (1-2)] used in Example 1, the blended pigments shown in Table 1 were used, and ink was prepared according to the method of Example 1. As a result of preparing the transfer sheet and performing transfer recording,
High-density ink could be produced, transfer sheets uniformly coated without dye precipitation could be obtained, and cyan-colored records with high color densities as shown in Table 1 could be obtained.

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[Table] Example 3 (a) Preparation of ink Blending ratio Mixed pigment (3-1) (3-2) 7g (50%) 7g (50%) Cellulose acetate ^* 10g Methyl ethyl ketone 50g Total 74g * L-30 (product name) manufactured by Daicel Chemical Co., Ltd. Mixture with the above composition was treated with paint conditioner for 10 minutes to prepare the ink. The pigment and resin were completely dissolved, and an ink with a uniform high concentration solution could be obtained. (b) Preparation of transfer sheet Apply the above ink using a bar coater (RK Print).
Using Coat Instruments Co., Ltd., No. 1),
After coating on condenser paper and drying with hot air at 60°C, it was possible to obtain a transfer sheet with uniform coating without any dye precipitation. (c) Transfer recording Lay the ink-applied surface of the above transfer sheet over the recording medium and record using a thermal head under the following conditions to obtain a record with a clear cyan color and uniform high color density of 1.80 without image unevenness. was completed. The recording conditions, production of the recording medium, and measurement of color density used in this example were the same as in Example 1. Comparative Examples 3 and 4 Blended dyes of Example 3 [(3-1) and (3-2)
[Total] Instead of 14g, the pigment (3-1) alone
Using 14g, Comparative Example 3, and dye (3-2)
As Comparative Example 4, an ink was prepared in the same manner as in Example 1 using 14 g of a single product. In all of the obtained inks, significant precipitation of the dye was observed, and the transfer sheets were non-uniform. Subsequently, transfer recording was performed using this transfer sheet, but the image was cyan-colored transfer recording with many unevenness and heavy scratches. Example 4 (a) Preparation of ink Blend ratio of blended pigments (4-1) (4-2) 6g (60%) 4g (40%) Ethyl cellulose ^* 10g Methyl ethyl ketone 50g Total 70g * Manufactured by Hercules Co., Ltd. Treat the mixture with the above composition with a paint conditioner for 10 minutes. , prepared the ink. The pigment and resin were completely dissolved, and a uniform, highly concentrated solution of the ink could be obtained. (b) Creating a transfer sheet Apply the above ink using a bar coater (RK Print).
Using Cort Instruments, No. 1),
After coating on condenser paper and drying with hot air at 60°C, it was possible to obtain a transfer sheet with uniform coating without any dye precipitation. (c) Transfer recording Lay the ink-coated surface of the transfer sheet on the recording medium and record using a thermal head under the following conditions to obtain a record of a clear cyan color with a uniform high color density of 1.70 without image unevenness. was completed. Recording conditions used in this example, manufacturing of the recording medium,
The measurement of color density was the same as in Example 1. Comparative Examples 5 and 6 Instead of using 10 g of the blended pigment [total of (4-1) and (4-2)] in Example 4, as Comparative Example 5, 10 g of the pigment (4-1) above was used alone. ,
As Comparative Example 6, an ink was prepared in the same manner as in Example 1, except that 10 g of the dye (4-2) above was used alone. In the resulting ink, the dye was significantly precipitated, and the transfer sheet was non-uniform. Next, using this transfer sheet,
Transfer recording was performed, but the image was cyan-colored with many unevenness and scratches.

Claims (1)

[Scope of Claims] 1. In a heat-sensitive transfer material having a coloring material layer on a support, the coloring material layer has the general formula [] and the general formula []
A heat-sensitive transfer material characterized by containing a dye represented by: (In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ represent a linear or branched C ₁ to C ₃ alkyl group.) 2 Claims 1. In the thermal transfer material, the dye represented by the general formula [] is 5 to 95
%, a heat-sensitive transfer material containing 95 to 5% of a dye represented by the general formula [ ]. 3. In the thermal transfer material according to claim 1, R ¹ and R ⁴ of the general formulas [] and [] are
represented by a C ₁ to C ₄ straight chain or branched alkyl group, and R ² , R ³ , R ⁵ and R ⁶ are represented by a C ₁ to C ₄ straight chain alkyl group; Thermal transfer material. 4. In the thermal transfer material according to claim 1, R ¹ and R ⁴ of the general formulas [] and [] are represented by a methyl group, and R ² , R ³ , R ⁵ and R ⁶ are represented by an ethyl group. A thermal transfer material represented by .