JPH068641A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To form a blackish image excellent in developed color density and fastness and especially excellent in light fastness by adding at least one of three kinds of dyes respectively represented by general formulae to the dye layer containing a plurality of dyes arranged on one surface of a base sheet. CONSTITUTION:A black type thermal transfer sheet is obtained by arranging a dye layer containing a plurality of dyes on one surface of a base sheet. In this case, at least one of respective dyes represented by three kinds of general formulae 1-3 is added to the dye layer. In the formulae 1-3, R1 is a substituted or non-substituted alkyl group or the like, R2 is an alkoxycarbonyl group or the like R3 and R4 are a substituted or non-substituted alkyl group, R5 is a substituted or non-substituted aryl group or the like, R6 is a substituted or non-substituted alkyl group, R7 and R8 are a substituted or non-substituted alkylcarbonyl group or the like, R11 and R12 are a substituted or non-substituted alkyl group or the like R9 is CONHR or the like and R10 is a substituted or non-substituted alkyl group or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet, and more specifically, it is an object of the present invention to provide a thermal transfer sheet capable of forming a black image excellent in color density and various fastnesses, particularly in light fastness.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a method of forming various full-color images on paper or a plastic film by using a general method of thermal transfer using a sublimable dye. In this case, a thermal head of a printer is used as a heating means, and by heating for an extremely short time, four color dots of three primary colors or black of the three primary colors are transferred to a thermal transfer image-receiving sheet, and the multicolor color dots are transferred. To reproduce the full-color image of the original. Further, only one color such as black is transferred to the thermal transfer image receiving sheet to reproduce a high gradation monochrome image. The image formed in this way is extremely clear because the coloring material used is a dye and has excellent transparency, so the resulting image has excellent reproducibility and gradation of intermediate colors, and It is possible to form a high-quality image or a monochrome image which is similar to the image by the offset printing or the gravure printing and which is comparable to the full-color photographic image.

[0003]

[Problems to be solved by the invention] However,
The conventional black heat transfer sheet used in the above heat transfer method is not excellent in color density and various fastnesses, particularly light fastness, because the combination of the three primary colors of yellow, magenta and cyan is not appropriate. Therefore, an object of the present invention is to provide a thermal transfer sheet capable of forming a black image excellent in color density and various fastnesses, especially in light resistance.

[0004]

The above object can be achieved by the present invention described below. That is, the present invention is a black thermal transfer sheet in which a dye layer containing a plurality of dyes is provided on one surface of a substrate sheet, wherein the dye layer is at least one of the dyes represented by the following general formula 1, A thermal transfer sheet comprising at least one kind of dye represented by the general formula 2 and at least one kind of dye represented by the general formula 3.

[Chemical 2](R in the above general formula₁Is a substituted or unsubstituted alkyl group
Or an alkoxy group, R_TwoIs an alkoxycarbonyl
Group, alkylaminocarbonyl group, alkoxy group, ar
Coxyalkoxy group, alkyl group, cycloalkyl group or
Is a heterocyclic group, R_ThreeAnd R_FourIs a substituted or unsubstituted alkyl
R group, R₅Is a substituted or unsubstituted aryl group or substituted or
Is an unsubstituted aromatic heterocyclic group, R₆Is a substituted or unsubstituted
Alkyl group, cycloalkyl group or NR ₇R ₈To R ₇
And R ₈Is a substituted or unsubstituted alkylcarbonyl group or
A substituted or unsubstituted arylcarbonyl group is represented by R₁₁as well as
R₁₂Is a substituted or unsubstituted alkyl group, aryl group,
R is a cycloalkyl group or vinyl group.₉Is CONHR,
NHCOR, SO_TwoNHR, NHSO_TwoR (R is replaced or
Is an unsubstituted alkyl group, cycloalkyl group, aryl group
Or an aromatic heterocyclic group), R₁₀Is replaced or not
Substituted alkyl group, alkoxy group, alkylcarbonyl group
Mino group, alkylsulfonylamino group, carbamoyl
Group, sulfamoyl group, hydrogen atom or halogen atom
You )

[0006]

By using a specific dye in combination, it is possible to provide a thermal transfer sheet capable of forming a black image excellent in color density and various fastnesses, especially in light resistance.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. The dye used in the present invention is
Any dye may be used as long as it is represented by the general formulas 1 to 3. Specific examples of particularly preferable dyes in the general formulas 1 to 3 are shown in Tables 1 to 3 below. Also, these dyes may be used in combination with other conventionally known dyes.

[0008]

Table 1 Dyes of general formula 1 (represented by substituents).

Table 2 Dyes of general formula 2 (represented by substituents).

TABLE 3 Dyes of general formula 3 (represented by substituents).

The thermal transfer sheet of the present invention is characterized by using the specific dyes as described above in combination, and other configurations may be the same as those of the conventionally known thermal transfer sheets.
As for the use ratio of each dye, when the dye of the general formula 1 is set to 100, the dye of the general formula 2 is 50 to 300, and the dye of the general formula 3 is a mixture of three dyes in a weight ratio of 50 to 400. Preference is given to using. If the use ratio is greatly deviated, a jet black clear black color cannot be obtained, and a yellowish, bluish, reddish, or other black color is obtained, and light resistance is also reduced. The base sheet used for the thermal transfer sheet of the present invention using the above dye may be any one as long as it has conventionally known heat resistance and strength to some extent, for example, 0.5 to 50.
μm, preferably about 3 to 10 μm thick paper, various processed papers, polyester film, polystyrene film,
A polypropylene film, a polysulfone film, a polycarbonate film, an aramid film, a polyvinyl alcohol film, cellophane and the like are used, and a polyester film is particularly preferable. The dye layer provided on the surface of the substrate sheet as described above is a layer in which the plurality of dyes are combined and 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 hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, acetyl butyric acid. Cellulose-based resins such as cellulose, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetoacetal, polyvinyl pyrrolidone, polyacrylamide and other vinyl-based resins, and the like, among them, polyvinyl butyral, polyvinyl acetal, ethyl cellulose and ethyl. Hydroxyethyl cellulose is preferable from the viewpoints of heat resistance and dye migration.

The dye layer of the thermal transfer sheet of the present invention is basically formed of the above-mentioned materials, but may also contain various additives similar to conventionally known ones, if necessary. Such a dye layer is preferably prepared by adding a plurality of the above dyes in a suitable solvent, a binder resin, and other optional components to dissolve or disperse each component to prepare a coating liquid or ink for forming a dye layer, This is applied and dried on the above-mentioned substrate sheet to form. The dye layer thus formed has a thickness of 0.2 to
The dye has a thickness of about 5.0 μm, preferably 0.4 to 2.0 μm, and the dye in the dye layer is 5 times the weight of the dye layer.
Suitably it is present in an amount of ˜70% by weight, preferably 10 to 60% by weight. The thermal transfer sheet of the present invention as described above is sufficiently useful as it is for thermal transfer, but an anti-adhesion layer, that is, a release layer may be further provided on the surface of the dye layer, and by providing such a layer. It is possible to prevent adhesion between the thermal transfer sheet and the thermal transfer image-receiving sheet during thermal transfer, and to use a higher thermal transfer temperature to form a blackish image having a more excellent density.

As the release layer, even if only the adhesion-preventing inorganic powder is attached, a considerable effect is exhibited.
For example, from a resin having excellent releasability such as a silicone polymer, an acrylic polymer, or a fluorinated polymer, 0.01 to
It can be formed by providing a release layer having a thickness of 5 μm, preferably 0.05 to 2 μm. The inorganic powder or releasable polymer as described above can exert a sufficient effect even when incorporated in the dye layer. Further, a heat-resistant layer may be provided on the back surface of such a thermal transfer sheet in order to prevent adverse effects due to the heat of the thermal head. Using the thermal transfer sheet as described above, the thermal transfer image-receiving sheet used for forming a black image may be any as long as its recording surface has a dye-accepting property to the dye.
Further, in the case of paper, metal, glass, synthetic resin or the like having no dye receptive property, the dye receptive 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, a thermal printer (for example, , Hitachi, video printer VY-10
By controlling the recording time with a recording device such as 0), it is possible to sufficiently achieve the intended purpose by applying thermal energy of about 5 to 100 mJ / mm ² .

[0012]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the text, parts and% are based on weight unless otherwise specified. Examples 1 to 8 Dye layer inks having the following compositions were prepared and applied to a 6 μm-thick polyethylene terephthalate film having a heat-treated back surface so that the dry coating amount would be 1.0 g / m ² , and then the A black thermal transfer sheet of the invention was obtained. The combinations of the dyes are shown in Table 4 below. Ink Composition Dye of General Formula 1 in Table 1 Part a Dye of General Formula 2 in Table 2 b Part Dye of General Formula 3 in Table 3 c Part Polyvinyl acetoacetal resin 4 parts Toluene (96-a-b-c) / 2 Parts Methyl ethyl ketone (96-a-b-c) / 2 parts However, when the dye was insoluble in the above composition, DMF, dioxane, chloroform or the like was appropriately used as a solvent.

[0013]

[Table 4] Comparative Example 1 A thermal transfer sheet of Comparative Example was obtained in the same manner as in Examples 1 to 7 except that the following ink was used instead of the dye layer ink.

[0014]

[Chemical 3] 1-amino-2-phenoxy-4-hydroxyanthraquinone 1.8 parts 1- (3-methylphenyl) amino-4-methylaminoanthraquinone 3 parts Polyvinyl acetoacetal resin 4 parts Toluene 45 parts Methyl ethyl ketone 45 parts

Next, a synthetic paper (Yupo FPG # 150, manufactured by Oji Yuka) was used as the base sheet, and a coating solution having the following composition was applied to one surface of the paper at a rate of 10.0 g / m ² when dried. And then dried at 100 ° C. for 30 minutes to obtain a thermal transfer image-receiving sheet. Polyester resin (Vylon200, Toyobo) 11.5 parts Vinyl chloride / vinyl acetate copolymer (VYHH, UCC) 5.0 parts Amino-modified silicone (KF-393, Shin-Etsu Chemical Co., Ltd.) 1.2 parts Epoxy-modified Silly Corn (X-22-343, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.2 parts Methyl ethyl ketone / toluene / cyclohexanone (weight ratio 4: 4: 2) 102.0 parts

Thermal Transfer Recording Test The thermal transfer sheets of the present invention and the comparative example and the thermal transfer image receiving sheet are superposed with their dye layers and dye receiving surfaces facing each other, and a head applied voltage of 11 V is applied from the back surface of the thermal transfer sheet. , Maximum printing time 16 msec. Recording was carried out with a thermal head under the conditions described above, and the obtained black image was evaluated according to the following criteria, and the results shown in Table 5 below were obtained. Light fastness test the light resistance test of the obtained black-based image transfer test xenon fade meta (manufactured by Atlas, Ci35
Conducted in A) (black panel temperature 50 ° C., 50 kLu
x) was done. ○ ・ ・ ・ ・ No irradiation after 50 hours irradiation. × ・ ・ ・ ・ Discoloration is remarkable after irradiation for 50 hours. Measurement of color density The maximum B / of black images obtained in the thermal transfer recording test
Densitometer RD- manufactured by Macbeth, USA
The measurement results were shown in Table 5 below. In addition, Example 1
The characteristic curve of Comparative Example 1 is shown in FIG.

[0017]

[Table 5]

[0018]

[Effects] According to the present invention as described above, by using a specific dye in combination, a thermal transfer sheet capable of forming a black image excellent in color density and various fastnesses, particularly light fastness is provided. You can

[Brief description of drawings]

FIG. 1 is a diagram showing characteristic curves of Example 1 and Comparative Example 1.

Claims (1)

[Claims] 1. A substrate sheet containing a plurality of dyes on one surface thereof.
A black thermal transfer sheet with a dye layer
The dye layer contains less dye represented by the following general formula 1.
And at least one of the dyes represented by the general formula 2
And at least one of the dyes represented by the general formula 3
A thermal transfer sheet characterized in that [Chemical 1](R in the above general formula₁Is a substituted or unsubstituted alkyl group
Or an alkoxy group, R_TwoIs an alkoxycarbonyl
Group, alkylaminocarbonyl group, alkoxy group, ar
Coxyalkoxy group, alkyl group, cycloalkyl group or
Is a heterocyclic group, R_ThreeAnd R_FourIs a substituted or unsubstituted alkyl
R group, R₅Is a substituted or unsubstituted aryl group or substituted or
Is an unsubstituted aromatic heterocyclic group, R₆Is a substituted or unsubstituted
Alkyl group, cycloalkyl group or NR ₇R ₈To R ₇
And R ₈Is a substituted or unsubstituted alkylcarbonyl group or
A substituted or unsubstituted arylcarbonyl group is represented by R₁₁as well as
R₁₂Is a substituted or unsubstituted alkyl group, aryl group,
R is a cycloalkyl group or vinyl group.₉Is CONHR,
NHCOR, SO_TwoNHR, NHSO_TwoR (R is replaced or
Is an unsubstituted alkyl group, cycloalkyl group, aryl group
Or an aromatic heterocyclic group), R₁₀Is replaced or not
Substituted alkyl group, alkoxy group, alkylcarbonyl group
Mino group, alkylsulfonylamino group, carbamoyl
Group, sulfamoyl group, hydrogen atom or halogen atom
You )