JPH06143839A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer sheet forming a sharp image having sufficient density and showing excellent fastness and light resistance by forming a dye support layer containing a specific dye on one surface of a base material sheet. CONSTITUTION:A dye support layer containing a dye represented by formula I or II is formed on one surface of a base material sheet. In the formulae, X is N=N, Y is Cr<5> or N, Z is a residue of a coupling component, R<1> and R<2> are H, an alkyl group, an aryl group or an alkenyl group, R<3> is a cyano group, a nitro group, a carbamoyl group, H, an acyl group, an alkoxy group, an acyloxy group or an alkoxy carbonyloxy group, R<4> is H, a cyano group, an alkoxycarbonyl group, an aryl group, a heterocyclic aryl group, an alkyl group, halogen, an alkoxy group, an alkylthio group, an amino group, a nitro group, an alkylsulfonyl group or an electron withdrawing group and R<5> is H or a cyano group.

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 are known, but among them, sublimable dyes are used as recording agents,
This is carried on a base material sheet such as paper to form a thermal transfer sheet, which is overlaid on a transferable material that can be dyed with a sublimable dye, for example, polyester woven cloth, and thermal energy is applied in a pattern from the back surface of the thermal transfer sheet. Then, a sublimation transfer method in which a sublimable dye is transferred to a transfer target material is performed. 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 very 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 by offset printing or gravure printing and which is comparable to a full color photographic image. [0003]

(Problems to be Solved by the Invention) However, the most important problems in the thermal transfer method are the color density, sharpness and light resistance of the formed image. That is, in the case of high-speed recording, the application of heat energy is required to be performed in an extremely short time of seconds or less. Therefore, in such a short time, the sublimable dye and the transfer material are not sufficiently heated. , It is not possible to form an image with sufficient density. Therefore, in order to cope with such high speed recording, a sublimable dye excellent in sublimation property was developed.
Dyes with excellent sublimation properties generally have a small molecular weight, so the dye migrates over time or bleeds to the surface in the transferred material after transfer, causing the image to be distorted or unclear. There is a problem of heat transfer resistance such as aging or contamination of surrounding articles and a problem of light resistance due to a small molecular weight. When a sublimable dye having a relatively large molecular weight is used in order to avoid such a problem, the sublimation speed is inferior in the above high-speed recording method, so that an image having a satisfactory density cannot be formed as described above. there were. Therefore, an object of the present invention is to provide a clear image with sufficient density in a thermal transfer method using a sublimable dye, and the formed image has various fastnesses, particularly a thermal transfer sheet having excellent light resistance. Is to provide. [0004]

[Means for Solving Problems] The above object is achieved by the present invention described below. That is, the present invention comprises a base material sheet and a dye carrying layer formed on one surface of the base material sheet, and the dye contained in the dye carrying layer is represented by the following general formula (A) or (B). It is a thermal transfer sheet characterized by being a dye represented. [Chemical 2] (In the formula, X represents N = N, and Y represents CR ⁵ or N. Z
Represents a residue of the coupling component. R ¹ and R ² are a hydrogen atom, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted allyl group, an optionally substituted aryl group, an optionally substituted aralkyl group, It represents an optionally substituted heterocyclic group or an optionally substituted alkenyl group, and R ¹ and R ² may form a ring. R ³ represents a cyano group, a nitro group, a carbamoyl group, an aminocarbonyl group, an alkoxycarbonyl group, a hydrogen atom, an acyl group, an alkoxy group, an acyloxy group or an alkoxycarbonyloxy group. R ⁴ is a hydrogen atom, a cyano group, an alkoxycarbonyl group, an optionally substituted aryl group, an optionally substituted heterocyclic aryl group, an optionally substituted alkyl group, a halogen atom, an alkoxy group, an alkylthio group, an arylthio group , Amino group, imide group,
It represents a nitro group, an alkylsulfonyl group, an acylamino group, an arylsulfonyl group, an arylcarbonylamino group or an electron withdrawing group. R ⁵ represents a hydrogen atom or a cyano group. )

[0005]

[Function] By using a dye having a specific structure, the dye used can easily transfer to the material to be transferred even if heat energy is applied for an extremely short time, resulting in excellent color density, sharpness and light resistance. There is provided a thermal transfer sheet which gives a recorded image having

[0006]

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
Preferred coupling components represented by the general formula (A) or (B) and represented by X, Y and Z include the following.

[0007]

[Chemical 3]

[0008]

[Chemical 4] 11

[0009]

[Chemical 5] In the above formula, R and R'represent a residue containing C, H, N, O, S or a substituent consisting of a halogen atom. The dye used in the present invention is represented by the general formula (A) or (B), and can be obtained by coupling any known coupler by a known method. Specific examples of each dye and various performances when used in a thermal transfer sheet described below are exemplified below.

[0010]

Embedded image Specific examples of dyes

[0011]

[Chemical 7]

[0012]

[Chemical 8]

[0013]

[Table 1] Dye No. 1

[0014]

[Table 2] Dye No. 1

[0015]

[Table 3] Dye No. Two

[0016]

[Table 4] Dye No. Three

[0017]

[Table 5] Dye No. Four

[0018]

Table 6 Dye No. 5

[0019]

[Table 7] Dye No. 6

[0020]

[Table 8] Dye No. 7

[0022]

Table 9: Dye No. 8

[0023]

Table 10 Dye No. 9

[0024]

Table 11 Dye No. 10

[0025]

Table 12: Dye No. 11

[0026]

Table 13 Dye No. 12

[0027]

Table 14 Dye No. Thirteen

[0028]

Table 15 Dye No. 14

The thermal transfer sheet of the present invention is characterized by using the specific dye as described above, and other configurations may be the same as those of the conventionally known thermal transfer sheet. The base sheet used for the thermal transfer sheet of the present invention containing the above-mentioned 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.
m, preferably about 3 to 10 μm in thickness, 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. It is a film.

The dye-supporting layer provided on the surface of the substrate sheet as described above is a layer in which the dye represented by the general formula (A) or (B) is supported by an optional binder resin. As the binder resin for supporting the above-mentioned dye, any conventionally known binder resin can be used, and preferred examples include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, butyric acid acetate. Cellulosic resins such as cellulose, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetoacetal, polyvinylpyrrolidone, polyvinyl resins such as polyacrylamide, and the like. Among them, polyvinyl butyral and polyvinyl acetal are particularly heat resistant. ,
This is preferable from the viewpoint of 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, 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 supporting layer. It is formed by coating and drying on the above-mentioned substrate sheet.

The supporting layer thus formed has a thickness of 0.2 to
The thickness of the support layer is 5.0 μm, preferably 0.4 to 2.0 μm.
Suitably it is present in an amount of 70% by weight, preferably 10-60% 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-adhesion 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, 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. 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 a dye receptivity to the above dye, or 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, Ltd., video printer VY-100) and other recording devices to control the recording time so that thermal energy of about 5 to 100 mJ / mm ² is applied to achieve the intended purpose. Can be done.

[0035]

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. 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. Dyes in Tables 1 to 15 described above 3 parts Polyvinyl butyral resin 4.5 parts Methyl ethyl ketone 46.25 parts Toluene 46.25 parts However, when the dye is insoluble in the above composition, DMF, dioxane, chloroform or the like is appropriately used as a solvent. I was there. If the above solvent was not sufficiently dissolved, the filtrate was used.

Next, a synthetic paper (Yupo FPG # 150, manufactured by Oji Yuka Co., Ltd.) 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, Shin-Etsu Chemical Co., Ltd.) 1.2 parts Methyl ethyl ketone / toluene / cyclohexanone (weight ratio 4: 4: 2) 102.0 parts

The above-mentioned thermal transfer sheet of the present invention and the above-mentioned material to be transferred are superposed with their dye carrying layers and dye receiving surfaces facing each other, and the head applied voltage 1 is applied from the back surface of the thermal transfer sheet.
1 V, printing time 16.0 msec. Recording was carried out with a thermal head under the conditions of, and the results shown in Tables 1 to 15 were obtained.

Comparative Examples 1 to 5 The dyes shown in Table 16 below were used in place of the dyes used in Example 1, and the results shown in Table 16 below were obtained in the same manner as in Example 1.

[Table 16]

Comparative Example 1 = CI Disperse Blue 14 Comparative Example 2 = CI Disperse Blue 134 Comparative Example 3 = CI Solvent Blue 63 Comparative Example 4 = CI Disperse Blue 26 Comparative Example 5 = CI Disperse Violet 4 The recording density in is a value measured by a densitometer RD-918 manufactured by Macbeth Co., USA. The light resistance was evaluated as ○ when the sharpness of the image did not change after irradiation with a 50 KLux xenon arc lamp for 24 hours, Δ when the sharpness was slightly lost, and × when the sharpness was lost. did.

[0040]

[Effects] According to the present invention as described above, by using a dye having a specific structure, the dye used can easily be transferred to the transfer material even if heat energy is applied for an extremely short time, and a color is developed. Provided is a thermal transfer sheet which gives a recorded image excellent in density, sharpness and light fastness.

Claims (1)

[Claims] 1. A substrate sheet and a dye carrying layer formed on one surface of the substrate sheet, wherein the dye contained in the dye carrying layer is represented by the following general formula (A) or (B). A thermal transfer sheet characterized in that it is a dye. [Chemical 1] (In the formula, X represents N = N, and Y represents CR ⁵ or N. Z
Represents a residue of the coupling component. R ¹ and R ² are a hydrogen atom, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted allyl group, an optionally substituted aryl group, an optionally substituted aralkyl group, It represents an optionally substituted heterocyclic group or an optionally substituted alkenyl group, and R ¹ and R ² may form a ring. R ³ represents a cyano group, a nitro group, a carbamoyl group, an aminocarbonyl group, an alkoxycarbonyl group, a hydrogen atom, an acyl group, an alkoxy group, an acyloxy group or an alkoxycarbonyloxy group. R ⁴ is a hydrogen atom, a cyano group, an alkoxycarbonyl group, an optionally substituted aryl group, an optionally substituted heterocyclic aryl group, an optionally substituted alkyl group, a halogen atom, an alkoxy group, an alkylthio group, an arylthio group , Amino group, imide group,
It represents a nitro group, an alkylsulfonyl group, an acylamino group, an arylsulfonyl group, an arylcarbonylamino group or an electron withdrawing group. R ⁵ represents a hydrogen atom or a cyano group. )