JPH05124364A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To provide a thermal transfer sheet imparting a full-color image excellent in developed color density, sharpness and various fastnesses, especially, light fastness though the saturation of a magenta color is high in a thermal transfer method using a sublimable dye. CONSTITUTION:A thermal transfer sheet consists of a base material sheet and the dye support layer formed to one surface of the base material sheet and the magenta dye contained in the dye support layer is constituted of a mixture of an anthraquinone dye and an azo dye.

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 recorded image excellent in color density, sharpness and various fastnesses, particularly light fastness.

[0002]

2. Description of the Related Art Conventionally, various thermal transfer methods have been known. Among them, a sublimable dye is used as a recording agent, which is carried on a base material sheet such as paper to form a thermal transfer sheet and dyed with the sublimable dye. There is a sublimation transfer method in which a sublimable dye is transferred to a transfer target material by superimposing it on a transferable material such as a woven polyester cloth and applying heat energy in a pattern from the back surface of the thermal transfer sheet. Recently, there has been proposed a method of forming various full-color images on paper or plastic film by using the sublimation type thermal transfer system. In this case, the thermal head of the printer is used as the heating means, and a large number of three-color or four-color dots are transferred to the transfer material by heating for an extremely short time, and the full-color image of the original is formed by the multi-color dots. To reproduce.
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 of intermediate colors and gradation, and It is possible to form a high quality image which is similar to the image obtained by the offset printing or gravure printing and which is comparable to the full color photographic image.

[0003]

[Problems to be solved by the invention] However,
Reproduction of a full-color image in the thermal transfer method is a subtractive color mixture, and in such a subtractive color mixture, the saturation of magenta generally greatly affects the color reproduction range. Therefore, in the above-mentioned thermal transfer method, a magenta dye having a high saturation has been used as the magenta dye. However, when the saturation of the magenta dye is increased in this way, the fastness of the formed image, in particular,
There was a problem that the light resistance was lowered. Therefore, an object of the present invention is to provide a thermal transfer method using a sublimable dye,
It is an object of the present invention to provide a thermal transfer sheet which gives a full-color image excellent in color density, sharpness and various fastnesses, in particular, light fastness despite the high saturation of magenta color.

[0004]

The above object can be achieved by the present invention described below. That is, the present invention comprises a base sheet and a dye carrying layer formed on one surface of the base sheet, and the magenta dye contained in the dye carrying layer is an anthraquinone represented by the following formula 1 to formula 4. A thermal transfer sheet comprising a mixture of at least one type of azo type dye and at least one type of azo type dye represented by the following formulas 5 to 15.

[Chemical 5] (Wherein X and Y are -S -, - O-or -SO ₂ - _represents, R 1, _{R 2} and _{R 3} is a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group or an allyl group , R ₄ represents a halogen atom or a cyano group.)

[0005]

[Chemical 6]

[0006]

[Chemical 7] (K in the above formula is

[Chemical 8] And R ₄ , R ₅ and R ₆ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a substituted or unsubstituted amino group, an alkyl group, a cycloalkyl group, an allyl group, an aryl group, an aralkyl group. , An alkoxy group, an aryloxy group, an arylthio group, an alkylthio group, an alkoxycarbonyl group, an alkoxyalkyl group, an alkoxycarbonylalkyl group, an acylamino group, a sulfonylamino group, a ureido group, a carbamoyl group, a sulfamoyl group,
Represents an acyl group or an aromatic heterocyclic group, and R ₇ and R ₈ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a vinyl group, an allyl group, an aryl group, an alkoxyalkyl group, an aralkyl group, an alkoxycarbonyl. An alkyl group,
Represents a carboxyalkyl group or an alkoxycarboxyalkyl group, Y represents a hydrogen atom, a halogen atom, a cyano group,
A substituted or unsubstituted alkyl group, alkylformylamino group, alkylsulfonylamino group, flumylamino group,
An allylformylamino group, a sulfonylamino group, an allylsulfonylamino group, a carbamoyl group, a sulfamoyl group, an amino group, a carboxyl group, an alkoxy group or a ureido group, n represents an integer of 1 to 5, and R ₁ and R ₂ And R ₁ and Y may form a ring with each other. ).

[0007]

[Function] By mixing and using a specific dye,
It is possible to provide a thermal transfer sheet which gives a full-color image excellent in color density, sharpness and various fastnesses, particularly light fastness, even though the magenta color is highly saturated.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the following preferred embodiments. Examples of the anthraquinone dyes used in the present invention include the dyes represented by the above formulas 1 to 4, and these dyes can be used alone or as a mixture. Further, examples of the azo dye used in the present invention include the dyes represented by the above formulas 5 to 15, and these dyes can be used alone or as a mixture. The anthraquinone dyes and azo dyes suitable for use in the present invention are listed below in Tables 1 to 21 as represented by their substituents. The hollow columns in the table mean hydrogen atoms. These dyes themselves are known as disperse dyes and the like, and can be obtained from the market and used in the present invention.

[0009]

[Table 1] The dye of the formula 1

[0010]

[Table 2] The dye of the formula 1

[0011]

[Table 3] The dye of the formula 2

[0012]

[Table 4] Dye of the above formula 3

[0013]

[Table 5] Dyes of the above formula 3

[0014]

Table 6 Dyes of the above formula 3

[0015]

[Table 7] Dyes of the above formula 4

[0016]

[Table 8] Dyes of the above formula 5

[0017]

[Table 9]

[0018]

Table 10: Dyes of the above formula 6

[0019]

Table 11: Dyes of the above formula 6

[0020]

Table 12: Dyes of the above formula 6

[0024]

TABLE 13 Dyes of formula 7 above

[0022]

TABLE 14 Dyes of the above formula 8 Three

[0023]

Table 14: Dyes of the above formula 9

[0024]

Table 16: Dyes of the above formula 10

[0025]

TABLE 17 Dyes of formula 11 above

[0026]

Table 18: Dye of the above formula 12

[0027]

TABLE 19 Dyes of formula 13 above

[0028]

[Table 20] Dyes of the above formula 14

[0029]

[Table 21] Dyes of the above formula 15 The anthraquinone dye and the azo dye as described above differ depending on the particular dye selected, but generally, it is preferable to use them in a weight ratio of 10 to 90:90 to 10. If the proportion of the anthraquinone dye is too large, the color density is lowered, and the color reproducibility is deteriorated. On the other hand, if it is too small, the light resistance is lowered.

The thermal transfer sheet of the present invention is characterized by using the specific dye mixture as described above, and other constitutions may be the same as those of the conventionally known thermal transfer sheet. The substrate sheet used for the thermal transfer sheet of the present invention using the above-mentioned dye mixture may be any one as long as it has a conventionally known degree of heat resistance and strength, for example, 0.5 to 50 μm, Paper having a thickness of about 3 to 10 μm, various processed papers, polyester film, polystyrene film, polypropylene film, polysulfone film, polycarbonate film, aramid film, polyvinyl alcohol film, cellophane and the like are preferable, and polyester film is particularly preferable. is there. The dye carrying layer provided on the surface of the substrate sheet as described above is a layer in which the dye mixture is carried by any binder resin. As the binder resin for supporting the dye mixture, any conventionally known binder resin can be used,
Preferred examples are ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose,
Specific examples include cellulose-based resins such as hydroxypropyl cellulose, methyl cellulose, cellulose acetate, and cellulose acetate butyrate, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetoacetal, polyvinyl pyrrolidone, and polyacrylamide. Especially, polyvinyl butyral and polyvinyl acetal are preferable from the viewpoints of heat resistance, dye transferability and the like.

The dye-carrying 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 the conventionally known ones if necessary. Such a dye-supporting layer is preferably prepared by adding the above-mentioned dye mixture, a binder resin and other optional components to a suitable solvent to dissolve or disperse each component to prepare a coating liquid or ink for forming a support layer. Is applied and dried on the above-mentioned substrate sheet to form. The carrier layer thus formed has a thickness of 0.2 to 5.0 μm, preferably 0.4 to 2.0 μm.
and the dye mixture in the carrier layer is 5 to 70% by weight, preferably 10 to 60% by weight of the carrier layer.
It is preferably present in an amount of% by weight. The thermal transfer sheet of the present invention as described above is sufficiently useful for thermal transfer up to that point, but an anti-sticking layer, that is, a release layer may be further provided on the surface of the dye carrying layer, and such a layer is provided. As a result, it is possible to prevent the thermal transfer sheet from sticking to the material to be transferred during thermal transfer, use a higher thermal transfer temperature, and form an image of even higher density.

As the release layer, even if only the adhesion-preventing inorganic powder is adhered, a considerable effect is exhibited.
For example, it is possible to select 0.01 to
It can be formed by providing a release layer having a thickness of 5 μm, preferably 0.05 to 2 μm. Incidentally, the inorganic powder or the releasing polymer as described above has a sufficient effect even when incorporated in the dye carrying 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. The material to be transferred used for forming 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 dye, and In the case of paper, metal, glass, synthetic resin or the like having no property, 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, a thermal printer (for example, , Hitachi, video printer VY-100) and other recording devices to control the recording time.
By applying thermal energy of about 5 to 100 mJ / mm ² , the intended purpose can be sufficiently achieved. In particular, the thermal transfer sheet of the present invention is capable of forming a magenta image and is used in combination with a yellow and cyan thermal transfer sheet, or color reproduction is performed by a thermal transfer sheet provided with the yellow, magenta and cyan dye layers in a frame sequential manner. It is possible to provide a full-color image having excellent properties.

[0033]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the text, “part” or “%” is based on weight unless otherwise specified. Example A dye-carrying layer-forming ink composition having the following composition was prepared, and applied to a 6 μm-thick polyethylene terephthalate film having a heat-treated back surface so that the dry coating amount was 1.0 g / m ² and dried. To obtain a thermal transfer sheet of the present invention. Ink composition Anthraquinone dye a part Azo dye b part Polyvinyl butyral resin 4.5 parts Methyl ethyl ketone 45.75 parts Toluene 45.75 parts However, when the dye is insoluble in the above composition, DMF, dioxane, chloroform, etc. are used as a solvent. (The dyes used and their mixing ratios (a, b) are shown in Table 2 below).
2-32).

Next, a synthetic paper (Yupo FPG # 150, manufactured by Oji Yuka) was used as a base sheet, and a coating solution having the following composition was applied to one surface of the synthetic paper at a rate of 10.0 g / m ² when dried. And then dried at 100 ° C. for 30 minutes to obtain a transfer material. 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 sheet of the present invention and the material to be transferred are superposed with the dye carrying layer and the dye receiving surface facing each other, and a head applied voltage of 11 V and a printing time of 1 from the back surface of the thermal transfer sheet.
6 msec. Recording with the thermal head under the conditions of
Results of 2-32 were obtained. Color Reproducibility Test A yellow thermal transfer sheet was obtained in the same manner as in Example 1 except that the ink composition for forming a dye carrying layer having the following composition was used. C. I. Disperse Yellow 141 3 parts Polyvinyl butyral resin 4.5 parts Methyl ethyl ketone 46.25 parts Toluene 46.25 parts In the same manner as in the thermal transfer test, a yellow image is formed using the yellow thermal transfer sheet, and the same signal is used. A magenta image was overlaid and formed using the thermal transfer sheet of the present invention to form a red image. The obtained red image and the magenta image of the thermal transfer test were visually evaluated for color reproducibility according to the following criteria, and the results in Tables 22 to 32 were obtained. ◎ ・ ・ Very clear ○ ・ ・ ・ ・ ・ ・ Clear △ ・ ・ ・ ・ ・ ・ Slightly unclear × ・ ・ ・ ・ ・ ・ Unclear

The light resistance test The light resistance test of the resulting magenta image thermal transfer test xenon fade meta (manufactured by Atlas, Ci35
Conducted in A) (black panel temperature 50 ° C., 50 kLu
x), but none of them did not discolor after irradiation for 50 hours. Measurement of color density It was measured with a densitometer RD-918 manufactured by Macbeth Co., USA. Comparative Examples 1 to 10 The following dyes were used in place of the dyes used in the examples, and other results were obtained in the same manner as in example 1 and the results shown in Table 33 below were obtained. Dyes in Table 33 below a part Polyvinyl butyral resin 4.5 parts Methyl ethyl ketone 46.25 parts Toluene 46.25 parts

[0037]

[Table 22]

[0038]

[Table 23]

[0039]

[Table 24]

[0040]

[Table 25]

[0041]

[Table 26]

[0042]

[Table 27]

[0043]

[Table 28]

[0044]

[Table 29]

[0045]

[Table 30]

[0046]

[Table 31]

[0047]

[Table 32]

[0048]

[Table 33]

[0049]

[Effects] According to the present invention as described above, by mixing and using a specific dye, the color density, sharpness and various fastnesses, particularly light fastness, are improved even though the magenta color saturation is high. It is possible to provide a thermal transfer sheet that gives an excellent full-color image.

Claims (3)

[Claims] 1. A magenta dye comprising a base sheet and a dye carrying layer formed on one surface of the base sheet, wherein the magenta dye contained in the dye carrying layer is an anthraquinone-based compound represented by the following formulas 1 to 4. At least one kind of dye and the following formula 5 to formula 1
5. A thermal transfer sheet, which is a mixture with at least one kind of azo dye represented by 5. [Chemical 1] (Wherein X and Y are -S -, - O-or -SO ₂ - _represents, R 1, _{R 2} and _{R 3} is a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group or an allyl group , R ₄ represents a halogen atom or a cyano group.) [Chemical 3] (K in the above formula is And R ₄ , R ₅ and R ₆ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a substituted or unsubstituted amino group, an alkyl group, a cycloalkyl group, an allyl group, an aryl group, an aralkyl group. , An alkoxy group, an aryloxy group, an arylthio group, an alkylthio group, an alkoxycarbonyl group, an alkoxyalkyl group, an alkoxycarbonylalkyl group, an acylamino group, a sulfonylamino group, a ureido group, a carbamoyl group, a sulfamoyl group,
Represents an acyl group or an aromatic heterocyclic group, and R ₇ and R ₈ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a vinyl group, an allyl group, an aryl group, an alkoxyalkyl group, an aralkyl group, an alkoxycarbonyl. An alkyl group,
Represents a carboxyalkyl group or an alkoxycarboxyalkyl group, Y represents a hydrogen atom, a halogen atom, a cyano group,
A substituted or unsubstituted alkyl group, alkylformylamino group, alkylsulfonylamino group, flumylamino group,
An allylformylamino group, a sulfonylamino group, an allylsulfonylamino group, a carbamoyl group, a sulfamoyl group, an amino group, a carboxyl group, an alkoxy group or a ureido group, n represents an integer of 1 to 5, and R ₁ and R ₂ And R ₁ and Y may form a ring with each other. ) 2. The thermal transfer sheet according to claim 1, wherein K is K ₂ . 3. The thermal transfer sheet according to claim 1, wherein the azo dye is at least one selected from the dyes represented by formulas (5), (6) or (10) to (15).