JP2825563B2 - Yellow color thermal sublimation transfer sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a yellow color heat-sensitive sublimation transfer sheet for a heat-sensitive sublimation transfer system.

More specifically, in a method of sublimating and transferring onto an image receiving paper by heating with a heating element such as a thermal head to obtain a color copy with good gradation, it has good dyeing and coloring properties and fastness. The present invention relates to a transfer sheet from which an excellent color copy can be obtained.

[Conventional technology]

In the thermal sublimation transfer system, a thermal transfer sheet coated with an ink containing a dye for sublimation thermal transfer is superimposed on an image receiving paper and heated and pressed with a thermal head. The dye sublimates and transfers to the image receiving paper, producing a full-color copy with good gradation. It is a system that can be obtained.

The first characteristic of the thermal sublimation recording method is that a thermal head is mainly used as a hardware device, and it is compact and excellent in maintainability and reliability. Secondly, since it is possible to obtain a mixed color image at a molecular level, a recording similar to a silver halide color photograph having excellent gradation and reproducibility can be obtained.

Further, this system has been applied to a wide variety of full-color recording systems such as CG (computer graphics), plate making systems, video movies and still video systems, and prepaid cards, and has recently received particular attention.

More specifically, a method in which a transfer sheet coated with a sublimable dye is heated by a thermal head controlled by a color signal of a still image to transfer and record the dye on an image receiving paper. Magenta,
Three primary colors of cyan are used. Furthermore, in order to provide light and dark, four primary colors may be used by adding black to the three primary colors.

[Problems to be solved by the invention]

The following conditions are required as the quality required for the yellow color heat-sensitive sublimation transfer sheet.

Good compatibility or solubility of the dye with the solvent and the binder resin in the ink used when applying to the transfer sheet.

The energy required for sublimation dyeing from the transfer sheet to the receiving paper is as low as possible, and an image with color value is obtained on the receiving paper.

The transferred image is yellow, which is one of the three primary colors of printing, and has little turbidity.

The dye does not recrystallize in the transfer sheet even when heated or humidified.

Good light fastness and storage stability of the transferred image.

Among the above-mentioned conditions, what is particularly required is that the ink has high solubility in a solvent and good compatibility with a binder resin.

That is, in the thermal sublimation transfer system, the dye must be completely dissolved in the binder resin on the transfer sheet in order to sublime at the molecular level. If the dye is transferred in a state of being insoluble in the binder resin on the transfer sheet, a uniform image cannot be obtained, the image density is low, and the commercial value is extremely poor.

Although development is underway to satisfy all the conditions necessary for the above transfer sheet, dyes with good sublimability are currently under further improvement due to poor durability and poor storage stability. Is desired.

[Means for solving the problem]

Means for Solving the Problems The present inventors have conducted intensive studies as a means for solving the above-mentioned problems, developed a transfer sheet containing a yellow-based compounding dye that satisfies all of the above conditions, and completed the present invention.

That is, in the present invention, general formula (I) Wherein R ₁ represents an alkyl group branched to the α-position, R ₂ represents a lower alkylene group, R ₃ represents an alkyl group, a cycloalkyl group, a substituted or unsubstituted aryl group, and a dye represented by the general formula: (II) Wherein R ₄ is an alkyl group, an alkoxyalkyl group, R ₅
Surprisingly found that a transfer sheet satisfying all of the above-mentioned conditions can be obtained by blending one or more dyes represented by the following formulas.

 Hereinafter, the present invention will be described in detail.

Specific examples of R _{1 in} the general formula (I) include an isopropyl group, a tert-butyl group, and an alkyl group branched at the α-position.
- methylhexyl group, 1-methylpentyl group and the like, specific examples of R ₂ include a methylene group as the alkylene group, an ethylene group, isopropylene group, butylene group, amylene group, C ₁ -C such hexylene ₆ lower alkylene groups, and specific examples of R ₃ include an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, and an n-butyl group, and a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group. And the like. Examples of the aryl group include a phenyl group, and the substituted aryl group include a p-methylphenyl group, an m-methylphenyl group, an o-methylphenyl group, a p-methoxyphenyl group, and an o-methoxyphenyl group. .

Specific examples of R _{4 in} the general formula (II) include, as an alkyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group,
Examples thereof include an n-butyl group, and examples of the alkoxyalkyl group include a methoxymethyl group, a methoxyethyl group, an ethoxyethyl group, and a propoxyethyl group. Examples of the alkyl group for R ₅ include a methyl group, an ethyl group, a propyl group, an isopropyl group, and an n-butyl group.

Furthermore, the compounding ratio of the compounds represented by the formulas (I) and (II) is arbitrary because it is determined by color matching to yellow.

The dye represented by the general formula (I) does not have completely good solubility in a solvent, but has particularly excellent storage stability in a transfer sheet, and has a greenish lemon-yellow hue with little haze. Also, the light resistance and storage stability of the transferred image are good. That is, conditions other than the above conditions are satisfied.

The dye represented by the general formula (II) tends to recrystallize a little in the transfer sheet and does not satisfy the above conditions, but otherwise has a slightly reddish punchy lemon. It is yellow, has little turbidity, and has good light fastness and storage stability of the transferred image. That is, conditions other than the above conditions are satisfied.

In the present invention, a combination of one or more dyes of the general formula (I) having an unsatisfactory solubility in a solvent in an ink and one or more dyes of the general formula (II) which is unsatisfactory in terms of recrystallization in a transfer sheet is provided. The synergistic effect further makes it possible to provide a transfer sheet that satisfies all of the above conditions, such as sublimation speed, color value, saturation, light resistance, storage stability, etc., with good solubility in solvents and binder resins. . Furthermore, good results can be obtained by adding another yellow colorant to the above combination.

The pyridone compounds of the general formulas (I) and (II)
It can be easily obtained by diazotizing a substituted aniline compound and performing a coupling reaction with an N-substituted pyridone compound.

As a method of manufacturing a transfer sheet, a thermal transfer recording ink composed of a dye, a binder resin, and a solvent is applied on a transfer sheet base material to prepare a transfer sheet. In this case, the amount of the dye in the thermal transfer recording ink is usually 2 to 5
% By weight.

As the resin for preparing the thermal transfer recording ink, those used in ordinary printing inks may be used, such as rosin, phenol, xylene, petroleum, vinyl, polyamide, nitrocellulose, and alkyl celluloses. Or an aqueous resin such as maleic acid, acrylic acid, casein, shellac and glue.

Examples of the solvent for preparing the ink include alcohols such as methanol, ethanol, propanol and butanol, cellosolves such as methyl cellosolve and ethyl cellosolve, aromatics such as benzene, toluene and xylene, ethyl acetate and butyl acetate. Esters, ketones such as acetone, methyl ethyl ketone and cyclohexanone, and hydrocarbons such as ligroin, cyclohexane and kerosene can be used.

The base material of the transfer sheet on which the ink is applied is condenser paper, tissue paper such as glassine paper, polyester,
Polyamide and polyimide films with good heat resistance such as polyimide are suitable, but these substrates are 2 to 20μ in order to improve the heat transfer efficiency from the thermal head to the dye.
A thickness of about m is appropriate.

Further, as the recording material, for example, polyethylene, polyolefin resin such as polypropylene, polyvinyl chloride, halogenated polymer such as polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, vinyl polymer such as polyacrylester, polyethylene terephthalate, Polyester resin such as polybutylene terephthalate, polystyrene resin, polyamide resin, copolymer resin of olefin such as ethylene and propylene and other vinyl monomers, ionomer, cellulose diacetate, cellulose resin, polycarbonate, polysulfone, polyimide, etc. , A woven fabric, a film, a sheet, a molded product, and the like.

Particularly preferred is a sheet or film made of polyethylene terephthalate.

Further, in the present invention, the resin obtained by adding acidic fine particles such as silica gel to the resin is coated on plain paper, impregnated, or laminated with a resin film, or a special acetylated processed paper is used. By doing so, good recording excellent in image stability under high temperature and high humidity can be performed. Also, films of various resins or synthetic papers made therefrom can be used.

Further, after transfer recording, for example, a polyester film is hot-pressed and laminated on the transfer recording surface to improve the coloring of the dye and stabilize the storage of the recording.

[Action and effect]

The yellow sublimation transfer sheet of the present invention containing one or more dyes represented by the general formula (I) and one or more dyes represented by the general formula (II) has a solubility in the solvent and the binder resin of the compounded dye. Is good, the storage stability of the dye in the binder resin on the sheet is good.

Furthermore, the transfer sheet of the present invention has a good sublimation speed by heating the thermal head, and the hue transferred to the image receiving paper is a yellow color of three primary colors of printing, less turbid and has high color value.

Further, the transferred image-receiving paper has very good light fastness and storage stability, and is a practically useful yellow-colored sublimation transfer sheet.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to Examples.

 In the examples, "parts" represents weight.

Example 1 (1) Method for adjusting ink 0.8 parts of a pyridone compound represented by the general formula (I): 1.2 parts of a pyridone compound represented by the general formula (II) represented by: 4.5 parts of polybutyral resin 46.25 parts of methyl ethyl ketone 46.25 parts of toluene The above pigment mixture is mixed with glass beads using a paint conditioner for about 30 minutes. Thus, the ink was adjusted.

(2) Transfer sheet preparation method Using a gravure proofing machine (plate depth 30 μm), apply the above ink to a 3.5 μm thick polyethylene terephthalate film with a heat-resistant backside applied so that the dry weight becomes 1.0 g / m ^2. Dried.

(3) Recording material preparation method Polyester resin 0.8 part (Vylon.103 Toyobo Tg = 47 ℃) EVA polymer sparse material (Elvaloy 741p Mitsui / Dupont Polychemical Tg =-
0.2 parts Amino-modified silicone 0.04 parts (KF-857 Shin-Etsu Chemical Co., Ltd.) Epoxy-modified silicone 0.04 parts (KF-103 Shin-Etsu Chemical Co., Ltd.) Methyl ethyl ketone / toluene / cyclohexane 9.0 parts (weight ratio 4: 4: 2) , A coating solution was prepared, and a bar coater (RK. Print Coat Instru) was applied to synthetic paper (Yoji FPG # 150 manufactured by Oji Yuka).
It was prepared by applying at a rate of 4.5 g / m ² when dried using No. 1 manufactured by ments Co., Ltd. and drying at 100 ° C. for 15 minutes.

(4) Transfer recording The transfer sheet and the recording material are overlapped with their respective ink-coated surfaces and coating liquid-coated surfaces facing each other.
Recording was performed under the conditions of 4.0 milliseconds, and a yellow color record having a color density of 2.1 was obtained. The color density was measured using a densitometer RD-918 manufactured by Macbeth Company, USA. A xenon fedometer (manufactured by Suga Test Instruments Co., Ltd.) was used as a light resistance tester for the obtained recording, and the black panel temperature was 63 ± 2 ° C.
The color was hardly discolored after irradiation for 40 hours, and the image stability under high temperature and high humidity was excellent.

Also, the fastness of the obtained recorded image was left in an atmosphere of 50 ° C. for 48 hours, and then the sharpness of the image was determined by the sharpness of the image and the coloring when the surface was rubbed with white paper. The white paper was not colored, and the fastness of the recorded image was good.

Examples 2 to 9 A transfer sheet and a recording material were prepared in the same manner as in Example 1 to perform transfer recording, using the dyes shown in Tables 1 to 4 in place of the dyes used in Example 1. However, Table-1
As a result, a yellow color of three primary colors of printing having the density shown in 4 was obtained, and the fastness was excellent as in Example 1.

Comparative Example A transfer sheet and a recording material were prepared in the same manner as in Example 1 using the dyes shown in Table 5 instead of the dyes used in Example 1, and transfer recording was performed. In Comparative Example 1, the solubility of the dyes (A) and (B) was low, and the dye (B) was very easily recrystallized in the transfer ribbon sheet. The storage stability in the sheet was poor and the color density was low.

In Comparative Example 2, the solubility of the dye (D) was high, but the storage stability in the ribbon sheet was inferior, and the dye was orange, so that the low solubility of the dye (C) was improved. The transfer image obtained without improvement was orange and had low color density.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41M 5/38-5/40 CA (STN)

Claims (1)

(57) [Claims] 1. The compound of the general formula (I) Wherein R ₁ represents an alkyl group branched to the α-position, R ₂ represents a lower alkylene group, and R ₃ represents an alkyl group, a cycloalkyl group, or a substituted or unsubstituted aryl group. And the general formula (II) [Wherein, R ₄ represents an alkyl group, an alkoxyalkyl group, and R ₅ represents an alkyl group].