JPH03175089A - Color for sublimable thermal recording and transfer sheet - Google Patents

Abstract

PURPOSE:To obtain a yellow color which melts with resin or a solvent component satisfactorily, sublimates into an image receiving element and enables color-fast records to be obtained with adequate color density by using a specific color for sublimable thermal recording. CONSTITUTION:Pyridoneazo color expressed by formula (I) is used alone or with another yellow component if necessary, as a yellow component. In the formula, R1, R2 are a substituted or a non-substituted alkyl group, R2 is a hydro gen atom, a substituted or a non-substituted alkyl group, an alkoxy group or a halogen atom. The color is mixed with any appropriate resin and solvent to manufacture an ink for thermal transfer recording. In this case, the color dosage in the ink is normally 2 to 5 weight%. The transfer sheet is manufac tured by applying a color ink containing this color to the surface of a transfer base. As the pyridoneazo color shown by the formula (I) is a sharp yellow, a full color can be obtained by combining the phyridoneazo color with clors magenta and cyan.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dye for thermal transfer recording and a transfer sheet used for color hard copies by a sublimation thermal transfer recording method.

[Conventional technology]

The sublimation thermal transfer image recording method is a method that sublimates dye by applying heat to form an image.Currently,
It is attracting attention as a method for obtaining full-color hard copies from televisions, CRT color displays, color facsimiles, magnetic cameras, etc. As the heat source, a heating element such as a thermal head or a laser, particularly a semiconductor laser, is used, and the amount of dye sublimated and transferred can be controlled by the applied thermal energy, so that good gradation recording can be obtained.

This method uses a heat-sensitive transfer sheet coated with sublimable dye on the transfer substrate, and transfers and records onto the receiver using a thermal head controlled by image signals. By using , full color is distantly related.

Examples of such heat-sensitive recording dyes include, for example, pyridone azo dyes represented by formula (n)
290583) is known.

[In formula (n), A is unsubstituted or has a substituent at the 2- or 4-position with respect to the azo bond. [Problems to be Solved by the Invention] The dye used for thermal transfer must satisfy various required performances as described below, and good image recording is only possible when these are satisfied.

- The dye has good solubility in the resin or solvent component used to create the heat-sensitive transfer sheet.

(2) The dye sublimes easily from the heat-sensitive transfer sheet to the image receptor (image recording layer) and has good affinity to the image receptor resin.

■The molecular extinction coefficient of the dye is large.

■Have optimal color characteristics as the three primary colors for full-color display.

■The imaged record must have excellent fastness such as light resistance, heat resistance, and stain resistance.

For example, pyridone azo dyes represented by the above general formula (II) have been studied for this recording method, but the current situation is that further improvements are required in order to satisfy the above conditions and put it into practical use. It is.

[Means to solve the problem]

As a result of extensive studies, the present inventors found the following general formula (I
) In formula c, 11,173 represents a substituted or unsubstituted alkyl group, R1 is a hydrogen atom, a substituted or unsubstituted alkyl group,
It was discovered that the pyridone azo dye represented by ], which represents an alkoxy group or a halogen atom, is a yellow dye that satisfies the above conditions, and by containing one or more of these dyes, sufficient color density can be obtained. The present inventors have discovered that robust records can be obtained using the method, and have completed the present invention.

In this case, the pyridone azo dye represented by the above general formula (I) may be used alone as a yellow component,
Further, it may be used in combination with other yellow components if necessary.

Next, the present invention will be explained in detail.

Examples of the unsubstituted alkyl group in the general formula (I) include methyl group, ethyl group, propyl group, isopropyl group, butyl group, t-butyl group, 2-methylpropyl group, pentyl group, hexyl group, and heptyl group. , straight-chain or branched alkyl groups such as octyl group, and examples of alkyl groups that may have substituents include alkoxyalkyl groups such as methoxyethyl group, γ-methoxypropyl group, and ethoxyethyl group; Halogenoalkyl groups such as fluoromethyl group and β-chloroethyl group, hydroxyalkyl groups such as hydroxyethyl group and hydroxypropyl group, methoxycarbonylmethyl group, ethoxycarbonylmethyl group, propoxycarbonylmethyl group, isopropoxycarbonylmethyl group, methoxycarbonyl group Examples include alkoxycarbonylalkyl groups such as ethyl groups, aralkyl groups such as benzyl groups and phenethyl groups, and cyanoalkyl groups such as cyanomethyl groups and cyanoethyl groups. Examples of alkoxy groups include methoxy groups, ethoxy groups, propoxy groups, and butoxy groups. etc., and halogen atoms include chlorine, bromine, iodine,
Examples include fluorine.

The compound of the present invention can be produced, for example, by the reaction route shown below.

[In the formula, R1, R2, and R3 have the same meanings as in the above general formula (I). ] -II The aniline derivative represented by formula (Ill) is reacted, for example, in hydrochloric acid water in the presence of sodium nitrite at a molar ratio of 1.0 to 1.3 times at 0 to 5°C for 1 to 2 hours to diazotize it. After that, excess sodium nitrite is decomposed with sulfamic acid,
pyridones represented by the general formula (rV) and 1 at 0 to 5°C.
By carrying out the coupling reaction for ~2 hours, the general formula (I
) is obtained.

As a method for producing a thermal transfer recording ink using the dye of the present invention, the dye may be mixed with an appropriate resin, solvent, etc. to form the recording ink. The amount of pigment is usually 2-5% by weight.

The transfer sheet can be produced by applying a dye ink containing the dye of the present invention onto a transfer substrate.

In addition, as a thermal transfer method, the ink obtained above is applied onto a suitable base material to create a transfer sheet, the sheet is placed on the recording medium, and then heated and heated from the back side of the sheet with a thermal recording head. For example, a method of pressing may be mentioned, and in this way, the dye on the sheet is transferred onto the recording medium.

The resin used for adjusting the above ink may be those used in ordinary printing inks, such as rosin-based, phenol-based, xylene-based, petroleum-based, vinyl-based, polyamide-based,
Oil-based resins such as alkyd-based, nitrocellulose-based, and alkyl celluloses, or water-based resins such as maleic acid-based, acrylic acid-based, casein, shellac, and glue can be used.

In addition, solvents for ink adjustment include alcohols such as methanol, ethanol, propatool, and butanol, cellosolves such as methyl cellosolve and ethyl cellosolve, aromatics such as benzene, toluene, and xylene, ethyl acetate, and butyl acetate. esters such as acetone, methyl ethyl getone, ketones such as cyclohexanone, hydrocarbons such as ligroin, cyclohexane, kerosene, dimethylformade, etc. can be used, but when using aqueous resins, water or water can be used. It is also possible to use a mixture of and the above-mentioned solvents.

Suitable substrates for applying ink include thin paper such as condenser paper and glassine paper, and films made of plastics with good heat resistance such as polyester, polyamide, and polyimide. In order to improve heat transfer efficiency to the dye, a thickness of about 5 to 50 μm is appropriate.

Examples of recording materials include polyolefin resins such as polyethylene and polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, and polyacrylic ester, polyethylene terephthalate, and polyethylene terephthalate. Polyester resins such as butylene terephthalate, polystyrene resins, polyamide resins, copolymer resins of resins such as ethylene and propylene and other vinyl monomers, ionomers, cellulose resins such as cellulose diacetate and cellulose triacetate, polycarbonates , fibers made of polysulfone, polyimide, etc.
Examples include woven fabrics, films, sheets, and carved objects.

Particularly preferred are woven fabrics, sheets or films made of polyethylene terephthalate.

In addition, in the present invention, plain paper coated or impregnated with acidic fine particles such as silica gel added to the resin, paper laminated with a resin film, or special processed paper treated with acetylation are used. By doing so, good recording with excellent image stability under high temperature and high humidity conditions can be achieved. It is also possible to use films of various resins or synthetic papers made from them.

Furthermore, by heat-pressing and laminating, for example, a polyester film on the transfer recording surface after transfer recording, it is possible to improve the color development of the dye and to stabilize the recording during storage.

[Action and effect]

Since the pyridone azo dye represented by the general formula (I) of the present invention has a vivid yellow color, it can be used in combination with, for example, a magenta color dye represented by the following structural formula and a cyan color dye represented by the following structural formula to produce a full color product. suitable for obtaining.

In this case, it may be possible to improve the solubility of the yellow dye component in the resin and solvent used in the production of the transfer sheet by mixing other dyes. Other yellow pigments may be mixed.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples, but these Examples do not limit the present invention. In addition, parts represent parts by weight, and % represents weight %.

Example 1 25.1 parts of ethyl doaminobenzoate was added to 2 parts of 6.8% hydrochloric acid water.
The mixture was dissolved in 50 parts and cooled to 0 to 5°C by adding 100 parts of ice. 445 parts of a 30% nitrous acid aqueous solution was added to the solution, stirred at 0 to 5°C for 1 hour, and diazotized to obtain a diazotized solution. The previously obtained diazotized solution was added dropwise to 37.7 parts of the pyridone compound of formula (V) at 0 to 5°C, and the mixture was stirred at the same temperature for 1 hour. Thereafter, the pH was adjusted to 4 to 5 with a 30% aqueous sodium hydroxide solution, heated and stirred at 50°C for 30 minutes, and the solid was filtered off and dried to form a yellow powder (A
) was obtained.

(The following is a blank space) Using the obtained compound (A), prepare the ink as follows.
A transfer sheet and recording material were prepared, and transfer recording was performed. Maximum absorption wavelength (λ-ax) of the compound in chloroform
) was 440 parts m.

(i) Ink preparation method Pigment of the above formula (A) 3-part polybutyral resin 4.5# methyl ethyl ketone 46.25 l toluene
46.25# The ink was prepared by treating the above pigment mixture with a paint conditioner for about 30 minutes using a glass piece.

(I1) How to create a transfer sheet Using a gravure proofing machine (plate depth 30μ), apply the above ink to a 9μm thick polyethylene terephthalate film whose back side has been heat-resistant treated so that the dry coating amount is 1.0g/rrr. Coated and dried.

(iii) Preparation of recording material Polyester resin 0.8 parts (vy
lon 103 Toyobo Tg-47°C) EVA polymer plasticizer 0.2 parts (Elvaloy 74
1 P Mitsui Polychemical Tg = -37°C) Amino modified silicone 0.04 part (KF
-857 Shin-Etsu Chemical Co., Ltd.) Epoxy modified silicone 0.04 part (KF
-103 Shin-Etsu Chemical Industry! Mix at least 9.0 parts of methyl ethyl ketone/toluene/cyclohexane (weight ratio 4:4:2), prepare a coating solution, and apply a bar coater (RK Pr1n) to synthetic paper (Yupo FPG11150, Tamago Yuka Co., Ltd.).
Manufactured by Coat Instruments, Inc.
1) at a dry rate of 4.5 g/n, and dried at 100°C for 15 minutes.

(iv) Transfer recording The above-mentioned transfer sheet and the above-mentioned recording material are placed one on top of the other with their respective ink-coated surfaces and coating liquid-coated surfaces facing each other, and a thermal head is applied from the back side of the thermal transfer sheet with a voltage of 10 V and a printing time of 4.0 V. Recording was performed under millisecond conditions, and a yellow record with a color density of 2.7 was obtained.

The color density was measured using a densitometer R manufactured by Macbeth Co., Ltd. in the United States.
It was measured using a D-514 model (filter: Wratten size 58).

Color density was calculated using the following formula.

Color density=fog. (io/I) 1o = Intensity of reflected light from standard white reflector I = Intensity of reflected light from test object In addition, the light resistance test of the obtained record was performed using a xenon fade meter (manufactured by Suga Test Instruments Co., Ltd.). ) at a black panel temperature of 63±2° C., there was almost no discoloration after 40 hours of irradiation, and the image stability was excellent even under high temperature and high humidity conditions.

In addition, fastness was determined by leaving the recorded image in an atmosphere at 50°C for 48 hours and determining the sharpness of the image and the coloring when the surface was rubbed with white paper.The sharpness of the image did not change. Furthermore, the white paper was not colored and the fastness of the recorded image was good.

Example 2 Compound (B) represented by the following formula synthesized by the same method as Example 1, and compound @J (C) coupled in the same manner
A total of 3 copies of 1.5 copies each were used to adjust the ink, prepare a transfer sheet, and a recording material, and perform transfer recording, resulting in a yellow recording with a color density of 2.6.

Jq When these records were subjected to a light fastness test in the same manner as in Example I, the records showed almost no change and were excellent in image stability at and under high temperatures.

Further, a fastness test was conducted in the same manner as in Example 1, but the sharpness of the image did not change, the white paper did not become colored, and the fastness of the recorded image was good.

Examples 3 to 17 Using the pyridone azo yellow dye shown in Table 1 synthesized according to the same method as in Example 1, ink adjustment, preparation of a transfer sheet, preparation of a recording material, and transfer recording were carried out. Each record shown in 1 was obtained.

All of these records were subjected to a light fastness test in the same manner as in Example 1, and the records showed almost no change and were excellent in image stability at and under high temperatures.

Further, a fastness test was conducted in the same manner as in Example 1, but the sharpness of the image did not change, the white paper did not become colored, and the fastness of the recorded image was good.

Comparative Example According to a method similar to Example 1, dye 3 of formula (C) above was prepared.
．． Using 0 copies, ink adjustment, transfer sheets, and recording materials were created.

When the pigment (C) was used alone, it was not completely dissolved in the ink and some crystals were deposited on the sheet surface. Transfer recording was performed using this transfer sheet, and the density was measured in the same manner as in Example 1 and found to be 0.9.

Further, when a light fastness test was conducted in the same manner as in Example 1, the color of the recording was faded.

Further, a fastness test was conducted in the same manner as in Example 1, but the image became unclear, the white paper was also colored, and the fastness of the recorded image was poor.

(Margin below)

Claims (1)

[Claims] 1. The following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In the formula, R^1 and R^3 represent substituted or unsubstituted alkyl groups, and R ^2 represents a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, or a halogen atom. ] A dye for sublimation heat-sensitive recording. 2. The following general formula (I) ▲Mathematical formula, chemical formula, table, etc.▼(I) [In the formula, R^1 and R^3 represent a substituted or unsubstituted alkyl group, R^2 is a hydrogen atom, Indicates a substituted or unsubstituted alkyl group, alkoxy group, or halogen atom. A transfer sheet for sublimation type heat-sensitive recording, comprising at least one or two or more dye components selected from the group of dyes represented by the following.