JPH0692043A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer sheet for a cyan color excellent in transfer properties, developed color density, sharpness and various fastnesses by using a dye having seven kinds, of groups represented by a specific general formula as the dye included in the dye support layer formed on one surface of a base material sheet. CONSTITUTION:A thermal transfer sheet is constituted of a base material sheet and the dye support layer formed on one surface of the base material sheet. In this case, as the dye included in the dye support layer, a dye represented by general formula [wherein R1 is a substituted/non-substituted alkyl group or an atom forming a 5-membered ring together with X, R2 is a substituted/non- substituted alkyl group, R3 is a hydrogen atom or a cyano group, R4 and R5 are a hydrogen atom, a halogen atom or -NHR (wherein R is a substituted/non- substituted alkyl group), R6 is a hydrogen atom or an alkyl group, R7 is an alicyclic hydrocarbon group, X is a 7 hydrogen atom or an atom or atom group forming a 5-membered ring together with R1 and n is 1 or 2] is used.

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, a cyan color capable of forming a recorded image excellent in transferability, color density, vividness and various fastnesses, particularly heat resistance and light fastness. The purpose of the present invention is to provide a thermal transfer sheet.

[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 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 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, the heat transfer resistance and the 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 support such high-speed recording, a sublimable dye having excellent sublimation property has been developed. However, since a dye having excellent sublimation property generally has a small molecular weight, it can be used in a transfer material after transfer. At the time, the dye migrates with time or bleeds on the surface, and the image formed at the corner is disturbed, becomes unclear, or contaminates surrounding articles. Problem is occurring. 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, the 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 excellent various fastnesses, particularly excellent heat transfer resistance and light resistance. Is to provide a thermal transfer sheet. [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 a dye represented by the following general formula (1). Is a thermal transfer sheet. [Chemical 2] (Wherein R ₁ in the above formula is a substituted or unsubstituted alkyl group, cycloalkyl group, aralkyl group, or aryl group,
Alternatively, represents an atom or an atomic group forming a 5-membered ring or a 6-membered ring together with X, R ₂ is a substituted or unsubstituted alkyl group,
It represents a cycloalkyl group, an aralkyl group or an aryl group.
In addition, R ₁ and R ₂ may form a 5-membered ring or a 6-membered ring which may contain an oxygen atom or a nitrogen atom. R ₃ is a hydrogen atom, a halogen atom, a cyano group, an alkyl group which may have a substituent, a cycloalkyl group, an alkoxy group, an aralkyl group, an aryl group, an acyl group, an acylamino group, a sulfonylamino group, a ureido group, carbamoyl. Represents a group, a sulfamoyl group or an amino group. R ₄ and R ₅ represent a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a halogen atom or —NHR, and R represents a substituted or unsubstituted alkyl group, alkylcarbonyl group, arylcarbonyl group, alkylsulfonyl group, Represents an arylsulfonyl group. R ₆ represents a hydrogen atom or a substituted or unsubstituted alkyl group. R ₇ represents an alicyclic hydrocarbon group, a heterocyclic group, an alkenyl group, an alkylcarbonyl group or an arylcarbonyl group. X represents a hydrogen atom or represents an atom or atomic group forming a 5-membered ring or 6-membered ring together with R _1, and n represents 1 or 2. )

[0005]

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

[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 represented by the general formula (1) used in the present invention is a known method, for example, a compound represented by the following general formula (2) and a p-phenylenediamine derivative represented by the general formula (3). And can be easily produced by coupling with and in the presence of an oxidizing agent such as silver chloride, ammonium persulfate, and red blood salt.

[0007]

[Chemical 3] (In the formula, R _{1 to} R ₇ , X and n are as defined above, and Y represents a hydrogen atom or a halogen atom.)

Examples of preferred substituents represented by R _{1 to} R ₅ in the above general formula (1) are alkyl groups such as methyl group, ethyl group, propyl group and butyl group; methoxyethyl group, ethoxyethyl group and the like. A hydroxyalkyl group such as hydroxyethyl group and β-hydroxypropyl group; halogenoalkyl group such as chloroethyl group; cyanoalkyl group such as cyanomethyl group and cyanoethyl group; cycloalkyl group such as cyclohexyl group; benzyl group, Aralkyl group such as phenethyl group; aryl group such as phenyl group, tolyl group, halogenophenyl group, alkoxyphenyl group; hydrogen atom; halogen atom such as chlorine, bromine, iodine; cyano group; methoxy group, ethoxy group, propoxy group, Alkoxy group such as butoxy group; acetyl group, propanoyl group, benzene Acyl group such as ylamino group; acylamino group such as acetylamino group, benzoylamino group; sulfonylamino group such as methanesulfonylamino group, ethanesulfonylamino group, benzenesulfonylamino group; methylureido group, 1,3-dimethylureido group , Ureido groups such as ethylureido group; carbamoyl groups such as methylcarbamoyl group, ethylcarbamoyl group and phenylcarbamoyl group; sulfamoyl groups such as methylsulfamoyl group, ethylsulfamoyl group and phenylsulfamoyl group; methylamino group And amino groups such as ethylamino group, propylamino group, dimethylamino group and diethylamino group.

Examples of preferable substituents represented by R ₆ and R ₇ include alkyl groups such as methyl group, ethyl group, isopropyl group and nonanyl group; cycloalkyl group, 2-methylcyclopentyl group, cyclohexenyl group and the like. Alicyclic hydrocarbon groups; heterocyclic groups such as pyridyl group, thienyl group, furyl group and morpholinyl group; alkenyl groups such as 1-propenyl group, allyl group, isopropenyl group and 2-pentenyl group. Preferred specific examples of the dye of the general formula (1) suitable for the present invention are shown in Table 1 below. However, R _{1 in} the formula
Are all ethyl groups, X are all hydrogen atoms, and n is all 1.

[0010]

[Table 1]

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 carrying layer provided on the surface of the substrate sheet as described above is a layer in which the dye of the general formula (1) is carried by any 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,
Examples thereof include vinyl-based resins such as polyvinylpyrrolidone and polyacrylamide. Among these, polyvinyl butyral and polyvinyl acetal are particularly preferable from the viewpoints of heat resistance and dye transferability.

The dye-carrying layer of the thermal transfer sheet of the present invention is basically formed of the above-mentioned materials, but may further 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 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 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. This prevents the thermal transfer sheet from sticking to the transferred material during thermal transfer,
Higher thermal transfer temperatures can be used to form images of even greater density.

As this 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. 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, video printer VY
By controlling the recording time with a recording device such as -100), it is possible to sufficiently achieve the intended purpose by applying thermal energy of about 5 to 100 mJ / mm ² .

In particular, the thermal transfer sheet of the present invention can form a cyan image, and can be used in combination with the yellow and magenta thermal transfer sheets to provide a full-color image excellent in color reproducibility. As the dye of the yellow thermal transfer sheet used in combination with the thermal transfer sheet of the present invention, the yellow dye of the following structural formula is particularly suitable.

[Chemical 4]

Further, as the dye of the magenta heat transfer sheet used in combination with the heat transfer sheet of the present invention, the magenta dye having the following structural formula is particularly suitable.

[Chemical 5]

[0018]

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. Dye of Table 1 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 was appropriately used as a solvent. If the above solvent was not sufficiently dissolved, the filtrate was used.

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 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 respective 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 performed with a thermal head under the conditions of, and the results shown in Table 2 below were obtained.

[0021]

[Table 2]

Comparative Examples 1 to 6 The results shown in Table 3 below were obtained in the same manner as in Example 1 except that the dyes shown in Table 3 below were used instead of the dyes used in Example 1.

[Table 5] Table 3

Comparative Example 1 = C.I. Disperse Blue 14 Comparative Example 2 = C.I. Disperse Blue 134 Comparative Example 3 = C.I. Solvent Blue 63 Comparative Example 4 = C.I. Disperse Blue 26 Comparative Example 5 = C.I. Disperse Violet 4 Comparative Example 6

[Chemical 7]

[Chemical 8] The recording density in the above is a value measured by a densitometer RD-918 manufactured by Macbeth Co., USA. The heat transfer resistance is ◎ when the recorded image is left in an atmosphere of 70 ° C. for 48 hours, the sharpness of the image does not change, and the white paper is not colored even if the surface is rubbed with white paper. When the sharpness is lost and the white paper is slightly colored,
Sharpness is lost and white paper is colored as △,
The image was unclear and the white paper was markedly marked with x. Light resistance test The light resistance test of the blue image obtained by the thermal transfer test was performed using a xenon fade meter (Ci3 manufactured by Atlas Co., Ltd.).
5A) (black panel temperature 50 ° C, 50KLu
x) was done. ◯: Almost no fading after irradiation for 50 hours. B: Slight fading is observed after irradiation for 50 hours. X: Fading is remarkable after irradiation for 50 hours.

[0024]

[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 the heat energy is applied for an extremely short time, and the high Provided is a thermal transfer sheet which gives a recorded image having a density and various fastnesses, and particularly excellent heat transfer resistance and light resistance.

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 a dye represented by the following general formula (1): A thermal transfer sheet characterized by being present. [Chemical 1] (Wherein R ₁ in the above formula is a substituted or unsubstituted alkyl group, cycloalkyl group, aralkyl group, or aryl group,
Alternatively, represents an atom or an atomic group forming a 5-membered ring or a 6-membered ring together with X, R ₂ is a substituted or unsubstituted alkyl group,
It represents a cycloalkyl group, an aralkyl group or an aryl group.
In addition, R ₁ and R ₂ may form a 5-membered ring or a 6-membered ring which may contain an oxygen atom or a nitrogen atom. R ₃ is a hydrogen atom, a halogen atom, a cyano group, an alkyl group which may have a substituent, a cycloalkyl group, an alkoxy group, an aralkyl group, an aryl group, an acyl group, an acylamino group, a sulfonylamino group, a ureido group, carbamoyl. Represents a group, a sulfamoyl group or an amino group. R ₄ and R ₅ represent a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a halogen atom or —NHR, and R represents a substituted or unsubstituted alkyl group, alkylcarbonyl group, arylcarbonyl group, alkylsulfonyl group, Represents an arylsulfonyl group. R ₆ represents a hydrogen atom or a substituted or unsubstituted alkyl group. R ₇ represents an alicyclic hydrocarbon group, a heterocyclic group, an alkenyl group, an alkylcarbonyl group or an arylcarbonyl group. X represents a hydrogen atom or represents an atom or atomic group forming a 5-membered ring or 6-membered ring together with R _1, and n represents 1 or 2. )