JPH037387A - Black thermal transfer sheet - Google Patents

Abstract

PURPOSE:To obtain a black thermal transfer sheet with high pitch-blackness, coloring properties and preservability by using magenta dye of specific structure for blending with black. CONSTITUTION:The subject sheet consists of a base sheet and a black dye- bearing layer formed with blended dyes such as yellow, cyan and magenta on one surface of the base sheet. The magenta dye is at least one type which is selected from a group of dyes shown by formulae (I-1) to (I-6). In the formulae, R1, R2 are an alkyl group, an aralkyl group or an allyl group, X is a hydrogen atom, a halogen atom and other elements, R3, R4 and R5 are a hydrogen atom, an alkyl group, an allyl group and other elements, and n is an integer of 0, 1 or 2.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a thermal transfer sheet, and more specifically, to color density,
The purpose of the present invention is to provide a black thermal transfer sheet capable of forming a recorded image excellent in clarity and fastness, particularly in storage stability and resistance to change and fading.

(Prior Art) Various thermal transfer methods have been known in the past, but among them, a sublimation dye is used as a recording agent, this is carried on a base sheet such as paper to form a thermal transfer sheet, and the dye is dyed with a sublimation dye. The thermal transfer sheet is layered on a transferable material such as polyester woven cloth, and thermal energy is applied in a pattern from the back side of the thermal transfer sheet.
A sublimation transfer method is used in which a sublimable dye is transferred to a transfer material.

Also, recently, using the above-mentioned sublimation type thermal transfer method,
Various methods have been proposed for forming full-color images on paper and plastic films.

In this case, the printer's thermal head is used as a heating means, and by heating in an extremely short time, three or four colors can be printed.
A large number of colored dots are transferred to a transfer material, and a full-color image of an original is reproduced using the multicolored colored dots.

The image formed in this way is very clear because the coloring material used is dye, and has excellent transparency, so the resulting image has excellent intermediate color reproducibility and gradation, It is possible to form high-quality images that are similar to images produced by conventional offset printing or gravure printing, and comparable to full-color photographic images.

(The problem that the invention is trying to solve) However,
The most important problem when forming full-color images using the above thermal transfer method is that a black dye is required in addition to yellow, magenta, and cyan dyes, but there is currently no suitable black dye. , produces black thermal transfer sheets by blending yellow, magenta and cyan dyes.

In the case of this black thermal transfer sheet, the combination of the three colors, especially the combination thereof, is important.If a conventionally known magenta dye is used for the black color combination, the color value will be low even if the hue is good ( The problem is that relatively large amounts of dye must be used compared to other dyes, and, more importantly, traditional magenta dyes generally have low molecular weights, resulting in dye migration within the dye-receiving layer after imaging. However, there were problems in image preservation, such as the image blurring, bleeding out onto the surface of the dye-receiving layer, the hue shifting to black, loss of jet blackness, and contamination of other articles.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a black thermal transfer sheet that has excellent color development, jet blackness, storage stability, etc. even when using a black dye with a three-color combination. .

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention comprises a base sheet and a black dye-carrying layer formed on one side of the base sheet from blended dyes of three colors: yellow, cyan, and magenta, and the magenta dye is as defined in claim 1 above. The general formulas (I-1) to (I=6
This is a black thermal transfer sheet characterized by at least one dye selected from the group consisting of the following dyes.

(Function) By using a magenta dye with a specific structure in the black formulation, it is possible to provide a black thermal transfer sheet that is excellent in jet blackness, color development, storage stability, etc.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

Each of the yellow and cyan dyes used in the present invention is publicly known, and any conventionally known dyes can be used as the yellow dye and cyan dye, but a particularly preferable yellow dye is the general formula ( II), and the cyan dye is represented by general formula (III) and/or (IV)
It is a dye represented by

Furthermore, the magenta dye itself of the general formulas (I-1 to I-6) used in the present invention and which mainly characterizes the present invention is disclosed in Japanese Patent Application Laid-open No. 64
Although it is known in Japanese Patent No. 63194, it is completely unknown that the magenta dye can be combined with other yellow dyes and cyan dyes to form a black compound dye.

The blending ratio of the above three color dyes varies depending on each dye selected, but for boat fishing, 50 to 150 parts by weight of the cyan dye and 50 to 150 parts by weight of the magenta dye to 100 parts by weight of the yellow dye. is within the range of

The thermal transfer sheet of the present invention is characterized by using the above-mentioned specific blended dye, and other than that, the structure may be the same as that of conventionally known thermal transfer sheets.

The base sheet used in the thermal transfer sheet of the present invention containing the above compounded dye may be any conventionally known material having a certain degree of heat resistance and strength, for example, 0.5 to 50 μm, preferably is paper with a thickness of about 3 to IO μm, various processed papers, polyester film, polystyrene film, polypropylene film, polysulfone film, polycarbonate film, aramid film, polyvinyl alcohol film, cellophane, etc., and particularly preferred is polyester film. .

The dye-carrying layer provided on the surface of the base sheet as described above is a layer in which the dye of the general formula (I) is supported by an arbitrary binder resin.

As the binder resin for supporting the dye, any conventionally known binder resin can be used, and preferred examples include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, and butyric acid acetate. Examples include cellulose resins such as cellulose, vinyl resins such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetoacetal, polyvinylpyrrolidone, and polyacrylamide. Among these, polyvinyl butyral and polyvinyl acetal are particularly heat-resistant. , is preferable from the viewpoint of dye migration.

The dye-carrying layer of the thermal transfer sheet of the present invention is basically formed from the above-mentioned materials, but may also contain various conventionally known additives as required.

Such a dye-supporting layer is preferably prepared by adding the above-mentioned compounded dye, binder resin, and other optional components to a suitable solvent and dissolving or dispersing each component to prepare a coating liquid or ink for forming the support layer. It is formed by coating and drying on the above base sheet.

The thickness of the support layer formed in this manner is about 0.2 to 5.0 μm, preferably 0.4 to 2.0 μm, and the above-mentioned dye in the support layer is about 5 to 5.0 μm thick by weight of the support layer. 70% by weight,
Preferably, it is present in an amount of 10 to 60%.

The thermal transfer sheet of the present invention as described above is sufficiently useful for thermal transfer as it is, but an anti-adhesive layer, that is, a release layer may be further provided on the inside surface of the dye-carrying layer. By providing this, it is possible to prevent adhesion between the thermal transfer sheet and the transferred material during thermal transfer, and to use a higher thermal transfer temperature.
-layer! It is possible to form an image with a high density.

As this mold release layer, even if an inorganic powder with anti-adhesive properties is simply attached, it has a considerable effect. It can be formed by providing a release layer of 0.01 to 5 μm, preferably 0.05 to 2 μm.

Incidentally, the above-mentioned inorganic powder or mold-releasing polymer exhibits a sufficient effect even when included in the dye-carrying layer.

Furthermore, a heat-resistant layer may be provided on the back surface of such a thermal transfer sheet in order to prevent the adverse effects of the heat of the thermal head.

The transfer material used to form an image using the thermal transfer sheet as described above may be any material as long as its recording surface has dye receptivity to the above-mentioned dyes. If the material is paper, metal, glass, synthetic resin, etc. that does not have any properties, a dye-receiving layer may be formed on at least one surface thereof.

As the means for applying thermal energy used when performing thermal transfer using the thermal transfer sheet of the present invention as described above and the recording material as described above, any conventionally known applying means can be used.
For example, by controlling the recording time using a recording device such as a thermal printer (e.g., Video Printer VY-100 manufactured by Hitachi),
/mrr? By applying a certain amount of thermal energy, the intended purpose can be fully achieved.

(Example) Next, the present invention will be described in more detail with reference to reference examples, examples, and comparative examples. In the text, parts or percentages are based on weight unless otherwise specified.

Example 1 An ink composition for forming a dye-carrying layer having the following composition was prepared, and the dry coating amount was 1.0 g/rr? The thermal transfer sheet of the present invention was obtained by coating and drying to give a heat transfer sheet of the present invention.

Dye of the following structural formula 1 1.10 parts Dye of the following structural formula 2 0.85 parts Dye of the following structural formula 3 1.10 parts Polyvinyl butyral resin 4.5 parts Methyl ethyl ketone 4
6.25 parts toluene 46.25
However, when the dye was insoluble in the above composition, DMF, dioxane, chloroform, etc. were appropriately used as a solvent.

Example 2 A thermal transfer sheet of the present invention was obtained in the same manner as in Example 1 except that the following compounded dye was used in place of the compounded dye in Example 1.

Example 3 A thermal transfer sheet of the present invention was obtained in the same manner as in Example 1, except that the following blended dye was used in place of the blended dye in Example 1.

Comparative Example 1 A thermal transfer sheet of a comparative example was obtained in the same manner as in Example 1 except that the following compounded dye was used in place of the compounded dye in Example 1.

Next, synthetic paper (Yubo FP manufactured by Tamago Yuka Co., Ltd.) was used as a base sheet.
G#150), apply a coating liquid with the following composition on one side at a rate of 10.0g/rrr when dry,
The material to be transferred was obtained by drying at 00° C. for 30 minutes.

Polyester (H fat (Vylon200, manufactured by Toyobo) 1
1.5 parts vinyl chloride/vinyl acetate copolymer (VYHHlUccW
) 5.0 parts Amino-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.2 parts Epoxy-modified silicone (X-22-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.2 parts Methyl ethyl ketone / Toluene / Cyclohexanone (Heavy responsibility) Ratio 4:
4:2) l 02. Part O: The thermal transfer sheet of the present invention and the transfer material described above were stacked with their respective dye-carrying layers and dye-receiving surfaces facing each other, and a head applied voltage of 10 V and a printing time of 14.0 m were applied from the back side of the thermal transfer sheet.
Recording was performed with a thermal head under conditions of 5 ec, and the results shown in Table 1 below were obtained.

○ indicates that the image has lost sharpness and the white paper has been colored; △ indicates that the image has lost sharpness and the white paper has been colored; and × indicates that the image has become unclear and the white paper has been significantly colored.

(Effects) According to the present invention as described above, by using a magenta dye with a specific structure for black compounding, it is possible to provide a black thermal transfer sheet that is excellent in jet blackness, color development, storage stability, etc. .

Claims (2)

[Claims] (1) Consisting of a base sheet and a black dye-carrying layer formed on one side of the base sheet from blended dyes of three colors: yellow, cyan, and magenta, and the magenta dye has the following general formula (I-1). A black thermal transfer sheet characterized by being at least one dye selected from the group consisting of dyes represented by (I-6). ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ( I -1) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ( I -2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ( I -3) ▲ Mathematical formulas, chemical formulas, There are tables, etc. ▼ ( I -4) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ( I -5) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ( I -6) (R_1 and R_2 in the above formula are substituted or represents an unsubstituted alkyl group, aralkyl group, or aryl group, and R_1 and R_2 may form a 5-membered ring or a 6-membered ring that may contain an oxygen atom and/or a nitrogen atom. X is a hydrogen atom, Represents a halogen atom, an alkyl group that may have a substituent, an alkoxy group, a nitro group, a cyano group, an acylamino group, or an aryl group, and R_3, R_4, and R_5 are hydrogen atoms, substituted or unsubstituted alkyl groups, and aryl groups. , -CONHR, -SONHR, -SO_2N
HR, -NHCOCF_3, -SO_2R, -SOR,
It represents a substituent such as -SO_2CF_3, -CN or -CF_3 (wherein R is a substituted or unsubstituted alkyl group or aryl group), and n represents an integer of 0, 1 or 2. ) (2) The black thermal transfer sheet according to claim 1, wherein the yellow dye is represented by the following general formula (II), and the cyan dye is a dye represented by the following general formula (III) and/or (IV). ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (IV) (R in the above formula is substituted or unsubstituted. represents an alkyl group, aralkyl group, or aryl group, X represents a hydrogen atom, a halogen atom, an alkyl group that may have a substituent, an alkoxy group, a nitro group, a cyano group, an acylamino group, or an aryl group, and A or B represents an aromatic ring which may be the same or different, may be substituted or unsubstituted and may contain a heteroatom, and n
represents an integer of 0, 1 or 2. )