JPS6158791A - Transfer sheet for thermal recording - Google Patents

Abstract

PURPOSE:To provide the title transfer sheet imparting the transfer recording of a cyan color with good hue and color density and excellent in storage stability, constituted by containing a specific naphthoquinone dye, an oxidation inhibitor and a polymerization inhibitor in a color material layer. CONSTITUTION:A transfer sheet is formed by providing a color material layer containing a sublimable dye onto a support and used in a method for performing recording by heating said transfer sheet by a thermal recording head to transfer the sublimable dye in said color material layer to an object to be transferred. In said color material layer, at least one naphthoquinone dye represented by formula I [wherein R and R<1> are 1-8C (substituted alkyl or cycloalkyl] (e.g., a compound represented by formula II), an oxidation inhibitor (e.g., 2,6-di-t-butyl- p-cresol) and/or a polymerization inhibitor (e.g., hydroquinone) are contained.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (a) Field of Industrial Application The present invention relates to a transfer sheet used for image sublimation type thermal transfer recording.

(b) Prior Art Currently, color recording technologies using electrophotography, inkjet, thermal transfer, etc. are being considered.

The thermal transfer recording method is considered to be advantageous over other methods because the device is easy to maintain and operate, and the device and consumables are inexpensive.

Thermal transfer methods include a melting method in which a transfer sheet with a heat-melting ink layer formed on a base film is heated by a heat-sensitive head to melt the ink and transfer onto the recording medium, and a base film. There is a sublimation method, in which a transfer sheet on which a color material layer containing a sublimable dye is formed is heated by a thermal head to sublimate the dye, and then transferred and recorded onto the recording medium. By changing the applied energy, the amount of sublimation of the dye can be controlled, which facilitates gradation recording and is particularly advantageous for full-color recording.

In order to obtain full-color recording by thermal transfer recording using the sublimation method, transfer recording can be performed using yellow, magenta, and cyan transfer sheets in sequence, but conventionally, cyan transfer sheets are It has been proposed that transfer recording with good color tone and color density can be obtained by using a naphthoquinone dye (JP-A-Sho, Turf 1r
rri≠publication).

However, transfer sheets using these dyes have problems such as a decrease in sensitivity during storage and a decrease in color density during transfer recording. Furthermore, when using these anthraquinone dyes as a cyan transfer sheet, transfer recording with good color tone and color density cannot be obtained.

(c) Problems to be Solved by the Invention The present invention aims to provide a transfer sheet that can provide cyan transfer recording with good color tone and color density, and also has excellent storage stability.

Structure of the Invention (a) Means for Solving Problems The present invention is directed to heating a transfer sheet having a coloring material layer containing a sublimable dye on a support with a heat-sensitive recording head to reduce the sublimability in the coloring material layer. A transfer sheet used in a recording method for transferring a dye to a recording medium, wherein the colorant layer contains the following general formula CI) (wherein R and R1 are C! to C8 substitutions). or an unsubstituted alkyl group or a cycloalkyl group) and at least 7 kinds of antioxidants or polymerization inhibitors. That is.

R and R1 in the above general formula CI) are linear or branched cl to C, alkyl group, alkoxyalkyl group, hydroxyalkyl group, β-chloroa ethyl group, β
Examples include substituted alkyl groups such as -cyanethyl group, β-phenoxyethyl group, allyl group, benzyl group, β-phenylethyl group, and tetrahydrofurfuryl group, and cycloalkyl groups such as U-cyclohexyl group. In addition, as for the alkyl group λ-substituted alkyl group and cycloalkyl group of R and R1, if the number of carbon atoms is too large, the sublimation ability of the dye will decrease, so C! ~Ca is appropriate.

As the antioxidant, phenol-based, sulfur-based, and phosphoric acid-based oxidizing agents are preferred. For example, λ, 6-di-t-butyl-p-cresol, butylated hydroxyanine,
x, l-c-t-butyl-≠-ethylphenol, stearyl-β-(3,j-di-butyl-μm hydroxyphenyl)globionate, 2.2'-)tyrene-bis-(Hiro-methyl-+-1 -butylphenol), λ
, λ'-methylene-bis-(≠-ethyl-A-t-butylphenol), ≠, g'-thiobis-(3-methyl-J
-t-butylphenol), g, p'-butyrythene-his-(3-methyl-+-1-butylphenol), /,
/I-) lis-(2-methyl-Hiro-hydroxy-j-
t-butylphenyl)butane, /, 3. ! -) listyl-2,≠, tris(3,!-cy t-phthyl≠-hydroxybenzyl)benzene, tetrakis-[
Methylene-3-(!,j-di-t-butyl-hydroxyphenyl)propionate comethane, bis(3,
r-bis-(terhydroxy-!-t-butylphenyl)butyric acid coglycol ester, tocopherols')uf;yshf ocipropionate, cimilistylthiodipropionate, distearylthiodipropionate nate, triphenyl phosphite, diphenyl indecyl phosphite, diphenyl diisodecyl phosphite, Hiroshi, ≠-butylidene bis(3-methyl-
Examples include 4-t-butylphenyl-di-tridecyl) phosphite and tris(nonylphenyl) phosphite.

As polymerization inhibitors, hydroquinone, catechol, t-
Examples include phenols and naphthols such as 7" tylcatechol, α-su7tol, β-su7tol, 7.4t-dihydroxynaphthalene, and ha!-dihydroxynaphthalene, benzoquinone, and chloranil.

Among the above antioxidants and polymerization inhibitors, phenolic and tol compounds are particularly effective.

Furthermore, each of the above antioxidants and polymerization inhibitors can be used as a single compound, but several types can also be used at the same time. You may do so.

The amount of antioxidant and polymerization inhibitor used is relative to the pigment! It is appropriate to use it in a range of 100% by weight.

To prepare a transfer sheet, the above-mentioned dye and antioxidant or polymerization inhibitor are dissolved or dispersed in the form of fine particles in a medium together with a binder.An ink is prepared, and the ink is applied onto a base film. Just apply it and let it dry.

Binders for ink v14m include water-soluble resins such as cellulose, acrylic acid, and starch, and organic solvent-soluble resins such as acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, polyethersulfone, and ethyl cellulose. Examples include resin. In the case of an organic solvent-soluble resin, it is possible to use it not only as an organic solvent solution but also in the form of an aqueous dispersion.

In addition to water, media for ink preparation include alcohols such as methyl alcohol, isobutyl alcohol, and isobutyl alcohol, cellomelfs such as methyl cellosolve and ethyl cellulose, aromatics such as luene, xylene, and chlorobenzene, ethyl acetate, Esters such as butyl acetate, ketones such as acetone, methyl ethyl ketone, methyl ibutyl ketone, and cyclohexanone, chlorinated solvents such as methylene chloride, chloroform, and trichloroethylene sodium, ethers such as tetrahydro-7rane, and dioxane, N,N-dimethylformamide ,
Organic solvents such as N-methylpyrrolidone may be mentioned.

Is there a Hess film used to apply the ink to make the transfer sheet, like condenser paper or gratin paper? 5
Plastic films with good heat resistance such as 1M polyester, polyamide, and polyimide are suitable, and their thicknesses can range from 3 to 0 μm.

The ink can be applied to the base film using a reverse roll coater, gravure coater, rod coater, air coater, etc., and the thickness of the ink coating layer after drying is 0.37 to 54 m.
(Coating method, written by Yuji Harasaki, published by Maki Shoten, /PDP).

Functions and Effects of the Invention The naphthoquinone dyes represented by the general formula (1) are easily sublimed and have an excellent cyan color tone, so by using these dyes, it is possible to transfer a cyan color with good color tone and color density. Records can be obtained, but since these dyes have insufficient stability, the dyes decompose during storage of the transfer sheet, reducing the sensitivity of the transfer sheet and reducing color density during transfer recording.

However, by using the above-mentioned antioxidant or polymerization inhibitor together with the dye, decomposition of the dye can be prevented and the storage stability of the transfer sheet can be improved. Therefore, by using the transfer sheet of the present invention, it is possible to obtain cyan transfer records that are stable and have good color tone and color density even after long-term storage.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but these Examples are not intended to limit the present invention.

EXAMPLES Example 1~/Co and Comparative Example/~λ Dye l shown in Table 1! ? , polycarbonate resin (
Manufactured by Mitsubishi Chemical Industries, Ltd., Tubarex 702YA
s m product name) / r f s methylene chloride 707
And the antioxidant or polymerization inhibitor shown in Table 1 was treated with a paint conditioner for 70 minutes to prepare an ink.

Apply this ink using a bar coater (wet film thickness/-2μm)
A transfer sheet was obtained by coating a capacitor ffd (10 μm thick) with K and drying.

Immediately after and after the production of the transfer sheet, t.

After holding for t days under the conditions of .degree. C. (relative humidity ♂O%), transfer recording was performed on the recording medium using a thermal printer, and as a result, records of color densities (reflected color densities) shown in Table 1 were obtained.

Further, Table 1 shows the color density ratio of the transfer recording between the case using the transfer sheet immediately after production and the case using the transfer sheet after holding for t days under the above conditions.

The record of the thermal printer is as follows.

Main scanning and sub-scanning linear density 2lt dot/wn recording power: 0. tW/dot head heating time: 10 m5ec The recording medium is an aqueous dispersion of 31/L saturated polyester resin (manufactured by Toyobo Co., Ltd., trade name Pyronal MD-12001) and tata and silica (manufactured by Nippon Silkani Industry Co., Ltd.). , N
1pail K 220 A% (trade name) /r was mixed, and the prepared liquid was coated on art paper (700 μm thick) using a K bar coater (Wet Membrane Co., Ltd. μm) and dried.

Reflection color density was measured using a densitometer RD manufactured by Macbeth, USA.
-6/4 was measured using a mold (filter m: latte/11f, 2j).

Claims (2)

[Claims] (1) In a method of recording by heating a transfer sheet having a coloring material layer containing a sublimable dye on a support with a heat-sensitive recording head and transferring the sublimable dye in the coloring material layer to a recording medium. The transfer sheet used has the following general formula (I) ▲mathematical formula, chemical formula, table, etc. in the coloring material layer▼......(I) (wherein, R and R^1 are C_1 to C_8 1. A transfer sheet for heat-sensitive recording, comprising at least one naphthoquinone dye represented by a substituted or unsubstituted alkyl group or cycloalkyl group, and at least one antioxidant or polymerization inhibitor. (2) In the transfer sheet for heat-sensitive recording according to claim 1, the antioxidant and polymerization inhibitor are phenolic,
A substance characterized by being a naphthol-based, sulfur-based, and phosphoric acid-based compound.