JPH05585A - Dye for thermal transfer recording and thermal transfer sheet - Google Patents

Abstract

PURPOSE:To ensure a sharp image having sufficient density, various excellent fastnesses and especially excellent light fastness by using a dye for thermal transfer recording represented by a specific general formula and forming a thermal transfer sheet using said dye. CONSTITUTION:A dye thermal transfer recording is represented by general formula [Wherein X is =C(CN)-A, =C(COOR7)2 (wherein R7 may be same or different) or =C-ring where the ring contains Z being a reaction of a 5- or 6-membred ring represented by H2C-ring where the ring contains Z, which may have a fused ring]. A thermal transfer sheet is formed from a base material sheet and the dye supporting layer formed to one surface thereof and the dye added to dye supporting layer is formed from the above mentioned dye. In the above mentioned general formula, A is an electron withdrawing group, Z is -CO- and R1-R7 are a hydrogen atom, a halogen atom, a nitro group or an aryl group which may be substituted. By this method, a sharp image having sufficient density is obtained and various excellent fastnesses of the image and the especially excellent light fastness thereof are ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dye for thermal transfer recording and a thermal transfer sheet, and more specifically, it is capable of forming an image excellent in color density, sharpness and various fastnesses, particularly light fastness and settling fastness. The purpose is to provide a thermal transfer sheet that can be made.

[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 a 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,
The most important problems in the above thermal transfer method are the color density 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, the sublimable dye and the material to be transferred are not sufficiently heated in such a short time. , It is not possible to form an image with sufficient density.
Therefore, in order to support such high speed recording, sublimable dyes having excellent sublimation properties have been developed. However, dyes having excellent sublimation properties generally have a small molecular weight, and therefore, in the transfer material after transfer. In the above, there is a problem that an image formed due to insufficient light resistance easily fades. 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 heat transfer method using a sublimable dye, which gives a clear image with sufficient density, and the formed image has excellent various fastnesses, and particularly excellent heat resistance. To provide a recording dye and a thermal transfer sheet.

[0004]

The above object can be achieved by the present invention described below. That is, the present invention comprises a dye for thermal transfer recording represented by the following general formula (I) (hereinafter simply referred to as a dye), a base sheet and a dye carrying layer formed on one surface of the base sheet. The thermal transfer sheet is characterized in that the dye contained in the dye carrying layer is a dye represented by the following general formula (I).

[Chemical 3]

[0005]

[Chemical 4] A is an electron-withdrawing group, Z is -CO-, -NR _6- , -S.
-, -O- or -NH-, R ₁ is a hydrogen atom, R ₆ , a halogen atom, a nitro group, -OR ₆ , -SR ₆ or an optionally substituted allyl group, R ₂ is a hydrogen atom, a halogen atom, −
OR ₆ or —SR ₆ , R ₃ is a hydrogen atom, R ₆ , a halogen atom, a nitro group, an optionally substituted allyl group, or —O.
R ₆ , —SR ₆ , sulfamoyl group, carbamoyl group,
An acyl group, an acylamido group, a sulfonamide group, a ureido group or -NR ₆ R ₆ (R ₆ may be the same or different),

R ₄ is a hydrogen atom, a halogen atom, or --O
R _6, -SR _6, a cyano group, -COOR _6, a carbamoyl group or a sulfamoyl group, _{R 5} is a hydrogen atom, a halogen atom, -OR ₆ or _-SR 6, _{R 6} is an optionally substituted alkyl group, substituted Optionally substituted aryl group, optionally substituted cycloalkyl group or optionally substituted heterocycle, R ₇ is hydrogen atom, —R ₆ , optionally substituted allyl group, optionally substituted alkenyl group, substituted Optionally substituted heteroalkenyl group, optionally substituted arylalkyl group, optionally substituted heteroarylalkyl group, optionally substituted alkoxyalkyl group, optionally substituted oxycarbonylalkyl group, optionally substituted Represents a good carboxyalkyl group, an optionally substituted oxycarboxyalkyl group or an optionally substituted cycloalkylalkyl group. . The substituents R _{1 to} R ₅ may be adjacent to each other to form a ring. )

[0007]

By using a dye having a specific structure, the dye used can easily be transferred to the material to be transferred even when heat energy is applied for an extremely short time, and high density and excellent fastness, Provided is a thermal transfer sheet which gives an image having excellent light resistance.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the following preferred embodiments. The dye of the general formula (I) used in the present invention can be prepared by a known method, for example,

[Chemical 5] A benz [cd] indole-2 (1H) one derivative represented by the formula: N-alkylated, and then dehydrated and condensed with an active methylene compound.
After pre-N-alkylating the (IH) one, R _{1 to} R ₅
It can be synthesized by a method of introducing a group and then dehydrating and condensing with an active methylene compound. Other dyes described later can be similarly synthesized.

Preferred examples of the dye of the general formula (I) suitable for the present invention and the results of examining the image density and light resistance when a thermal transfer sheet is prepared by using the dye to form an image as described below, The results are shown in Tables 1 to 19 below.

[0010]

## STR6 ## Dye I-1

Embedded image Dye I-2

## STR8 ## Dye I-3

Embedded image Dye I-4

[0011]

Embedded image Dye I-5

Embedded image Dye I-6

[0012]

[Table 1] Dye I-1

[0013]

[Table 2] (Continued from Table 1)

[0014]

[Table 3] (Continued from Table 1)

[0015]

[Table 4] (Continued from Table 1)

[0016]

[Table 5] (Continued from Table 1)

[0017]

[Table 6] (Continued from Table 1)

[0018]

[Table 7] Dye I-2

[0019]

[Table 8] (Continued from Table 7)

[0020]

[Table 9] (Continued from Table 7)

[0021]

[Table 10] (Continued from Table 7)

[0022]

[Table 11] (Continued from Table 7)

[0023]

Table 12 Dye I-3

[Table 13] (Continued from Table 12)

[0024]

Table 14 Dye I-4

[0025]

[Table 15] (Continued from Table 14)

[0026]

Table 16 Dye I-5

[0027]

[Table 17] (Continued from Table 16)

[0028]

Table 18 Dye I-6

[Table 19] (Continued from Table 18)

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 a conventionally known degree of heat resistance and strength, for example, 0.5 to 50 μm.
m, preferably a 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, etc., particularly preferably polyester. It is a film.

The dye carrying layer provided on the surface of the substrate sheet as described above is a layer in which the dye of the general formula (I) is carried by any binder resin. As the binder resin for supporting the above-mentioned dye, any conventionally known one can be used, and preferable examples include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, butyric acid acetylate. Cellulosic resins such as cellulose, polyvinyl alcohol, polyvinyl acetate,
Polyvinyl butyral, polyvinyl acetoacetal,
Examples thereof include vinyl-based resins such as polyvinylpyrrolidone and polyacrylamide. Among these, polyvinyl butyral and polyvinyl acetal are particularly preferable from the viewpoint 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, 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, It is formed by coating and drying on the above-mentioned substrate sheet. The carrier layer thus formed is
0.2 to 5.0 μm, preferably 0.4 to 2.0 μm in thickness, and the dye 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%.

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 carrying layer. By providing the above, it is possible to prevent the thermal transfer sheet from sticking to the material to be transferred at the time of thermal transfer, use a higher thermal transfer temperature, and form an image with a more excellent density. As the release layer, even if only the adhesion-preventing inorganic powder is adhered, a considerable effect is exhibited. Further, for example, from a resin having excellent release property such as a silicone polymer, an acrylic polymer or a fluorinated polymer, .01-5
It can be formed by providing a release layer having a thickness of 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 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 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 to provide thermal energy of about 5 to 100 mJ / mm ² to achieve the intended purpose. Can be done.

In particular, the thermal transfer sheet of the present invention can form a yellow image and can be used in combination with a magenta and cyan thermal transfer sheet to provide a full color image having excellent color reproducibility.

[0035]

EXAMPLES The present invention will be described in more detail with reference to Reference Examples, Examples and Comparative Examples. In the text, “part” or “%” is based on weight unless otherwise specified. Reference Example 1 N-Ethyl-benz [cd] indole-2 (IH) one (16.9 g), malonnitrile (6 g) and phosphorus oxychloride (19.4 g) were added to 150 ml of toluene, and the mixture was heated with stirring on a water bath for 4 hours to react. Mix the mixture with methanol 60
Pour into 0 ml and filter the precipitated crystals. The crude product was recrystallized from a mixed solution of chloroform-methanol,
No. 75 dyes are obtained. This dye has a maximum absorption wavelength of 4
It was a yellow crystal having a melting point of 196 to 7 ° C., 41 nm (methanol). Reference example 2 formula

[Chemical 13] 9.3 g of a quaternary salt represented by and 3.4 g of cyanoacetic acid ethyl ester were added to 85 ml of acetonitrile, 5.3 ml of triethylamine was added thereto, and the mixture was heated under reflux for 1 hour, then the solvent was distilled off, and methanol was added. And the resulting crystals are collected by filtration. The crude product was purified by a column using silica gel, and the product of No. 10 in Table 10 was obtained. Dye 1 was obtained. This dye has a maximum absorption wavelength of 454 nm (methylene chloride) and a melting point of 8
It was a yellow crystal of 6 to 87 ° C.

Reference Example 3 Dyes shown in Tables 1 to 19 were obtained in the same manner as in Reference Examples 1 and 2 except that raw materials corresponding to the dyes shown in Tables 1 to 19 were used.

Example An ink composition for forming a dye carrying layer 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 it dried and the thermal transfer sheet of this invention was obtained. Dyes in Tables 1 to 3 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, manufactured by 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 transferred material 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.
0 V, printing time 4.0 msec. Recording was carried out with a thermal head under the conditions of, and the results shown in Tables 1 to 19 above were obtained. Comparative Examples 1-5 Using the dyes in Table 20 in place of the dyes in Example 1,
Others were the same as in Example 1, and the results in Table 20 were obtained.

[0040]

[Table 20]

Embedded image Dye 1: Dye 2: C.I. I. Solvent Yellow 56 Dye 3: C.I. I. Solvent Yellow 14 Dye 4: C.I. I. Disperse Yellow 3 Dye 5: C.I. I. Disperse Yellow 54

The color density in the above is a value measured by a densitometer RD-918 manufactured by Macbeth Co., USA. The light resistance was evaluated by irradiating a xenon lamp (1200 W) for irradiation time and dye residual ratio, and when the dye residual ratio was 80% or more after 40 hours irradiation, ◎, 79 to 50%
The evaluation was made as ◯ and less than 50% as x.
In addition, evaluation of light resistance in Tables 1 to 19 was also performed on the same basis as above.

[0042]

As described above, according to the present invention, by using a dye having a specific structure, the dye used can be easily transferred to the material to be transferred even if heat energy is applied for an extremely short time. There is provided a thermal transfer sheet which gives an image having high density and excellent various fastnesses, and particularly excellent light resistance and settling resistance.

[0043]

[Brief description of drawings]

FIG. 1 shows a xenon lamp (1) in a thermal transfer image using a dye of the present invention and a thermal transfer image using a dye of a comparative example.
The figure which shows the relationship between the irradiation time by 200 W) irradiation and the residual ratio of a dye.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryohei Takiguchi 1-1-1, Ichiya-Kagacho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd. (72) Inventor Hiroshi Eguchi 1-1-1, Ichigaya-ka, Shinjuku-ku, Tokyo No. 1 in Dai Nippon Printing Co., Ltd. (72) Inventor Kimiaki Kafuku 1-1 1-1 Ichigaya Kagacho, Shinjuku-ku, Tokyo Within Dai Nippon Printing Co., Ltd.

Claims (1)

Claims: 1. A dye for thermal transfer recording represented by the following general formula (I). [Chemical 1] [Chemical 2] A is an electron-withdrawing group, Z is -CO-, -NR _6- , -S.
-, -O- or -NH-, R ₁ is a hydrogen atom, R ₆ , a halogen atom, a nitro group, -OR ₆ , -SR ₆ or an optionally substituted allyl group, R ₂ is a hydrogen atom, a halogen atom, −
OR ₆ or —SR ₆ , R ₃ is a hydrogen atom, R ₆ , a halogen atom, a nitro group, an optionally substituted allyl group, or —O.
R ₆ , —SR ₆ , sulfamoyl group, carbamoyl group,
Acyl group, an acylamido group, a sulfonamido group, a ureido group, or _{-NR 6 R} 6 _(R 6 may be the same or different), _{R 4} is a hydrogen atom, a halogen atom, _-OR 6, -S
R ₆ , a cyano group, —COOR ₆ , a carbamoyl group or a sulfamoyl group, R ₅ is a hydrogen atom, a halogen atom or —O.
R ₆ or —SR ₆ , R ₆ is an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted cycloalkyl group or an optionally substituted heterocycle, R ₇ is a hydrogen atom, R ₆ , an optionally substituted allyl group, an optionally substituted alkenyl group, an optionally substituted heteroalkenyl group, an optionally substituted arylalkyl group, an optionally substituted heteroarylalkyl group, a substituted Represents an optionally substituted alkoxyalkyl group, an optionally substituted oxycarbonylalkyl group, an optionally substituted carboxyalkyl group, an optionally substituted oxycarboxyalkyl group or an optionally substituted cycloalkylalkyl group. The substituents R _{1 to} R ₅ may be adjacent to each other to form a ring. 2. A dye for thermal transfer recording according to claim 1, comprising a substrate sheet and a dye-carrying layer formed on one surface of the substrate sheet, and the dye contained in the dye-carrying layer. A thermal transfer sheet characterized in that