JP2940943B2 - Dye for thermal recording and transfer sheet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a transfer sheet for thermal transfer recording used for color hard copy by a sublimation thermal transfer recording system.

[Conventional technology]

The image recording method of the sublimation heat transfer method is a method of forming an image by sublimating a dye by applying heat, and is currently used as a method of obtaining a full-color hard copy from a television, a CRT color display, a color facsimile, a magnetic camera, and the like. Attention has been paid. As a heat source, a heating element such as a thermal head, or a laser, particularly a semiconductor laser is used, and the amount of the dye that undergoes sublimation transfer can be controlled by the applied heat energy, so that good gradation recording can be obtained.

In this method, a thermal transfer sheet in which a sublimable dye is applied to a transfer substrate is used to transfer and record a thermal transfer sheet of three primary colors of yellow, magenta, and cyan by a thermal head controlled by an image signal. Full color is achieved by use.

As such thermosensitive recording dyes, pyridoneazo dyes represented by the formula (II) (Reference: JP-A-62-290583)
It has been known.

[In formula (II), A is unsubstituted or has a substituent at the 2- or 4-position to the azo bond. [Problems to be Solved by the Invention] Dyes used for thermal transfer must satisfy various required performances as described below, and satisfactory image recording becomes possible only by satisfying these requirements.

Good solubility of the dye in the resin or solvent component used when preparing the thermal transfer sheet.

The dye is easily sublimated from the heat-sensitive transfer sheet to the image receptor (image recording layer), and has good affinity for the image receptor resin.

The dye has a large molecular extinction coefficient.

Having optimal color characteristics as three primary colors for full color display.

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

For this recording method, for example, pyridone azo dyes represented by the general formula (II) have been studied. However, there is no dye which satisfies the above conditions and can be put to practical use. Was not obtained.

[Means for solving the problem]

As a result of studying various dyes, the following general formula (I) having a substituent at the 3-position to the azo bond was obtained. (Where R ¹ is X is a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, a halogenoalkyl group,
Alkoxy group, aryloxy group, alkenyloxy group, cycloalkyloxy group, represents a halogenoalkyloxy group, Y represents an alkyl group, a cycloalkyl group, an aryl group, a halogenoalkyl group, R ² is a hydrogen atom, an alkyl group, It represents an alkyl group, a halogen atom or an alkoxy group which may have a substituent, and R ³ represents a hydrogen atom, an alkyl group or an alkyl group which may have a substituent. The pyridone-based azo dye represented by the formula (1) is a yellow dye that satisfies the above-mentioned conditions, and it has been found that robust recording can be obtained with a sufficient color density by containing one or more of these dyes. The present invention has been completed.

In this case, the pyridoneazo dye represented by the above general formula (I) may be used alone as a yellow component,
Further, even when used in combination with other yellow components as required, a robust recording can be obtained with the same color density.

 Next, the present invention will be described in detail.

In R ₁ , R ₂ and R ₃ in the general formula (I), the alkyl group means a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group and the like. Examples of the alkyl group include a cyclohexyl group and a cyclopentyl group, and examples of the alkenyl group include an allyl group, a 2-methylallyl group, a 2-chloroallyl group, and a 2-chloroallyl group.
It represents a bromoallyl group, a crotyl group, a 3-phenylallyl group, or the like.

As the aryl group, a phenyl group, an o-toluyl group,
m-toluyl group, p-toluyl group, p-chlorophenyl group, p-bromophenyl group, p-methoxyphenyl group,
It represents a p-trifluoromethylphenyl group, a p-nitrophenyl group, an m-chlorophenyl group or the like, and the halogenoalkyl group represents a chloroethyl group, a chloropropyl group, a bromoethyl group, an iodoethyl group or the like.

The alkoxy group represents a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a γ-methoxy group, and the like, the aryloxy group represents a phenyloxy group, a p-chlorophenyloxy group, and the like, and the alkenyloxy group includes Represents an allyloxy group, a 2-methylallyloxy group, or the like; a cycloalkyloxy group represents a cyclohexyloxy group, a cyclopentyloxy group; a halogenoalkyloxy group includes a chloroethyloxy group;
A chloropropyloxy group, a bromoethyloxy group, an iodoethyloxy group and the like can be mentioned.

The alkyl group which may have a substituent includes a methoxyethyl group, a γ-methoxypropyl group, an alkoxyalkyl group such as an ethoxyethyl group, a trifluoromethyl group, a halogenoalkyl group such as a β-chloroethyl group, and a hydroxy group. It represents a hydroxyalkyl group such as an ethyl group or a hydroxypropyl group, a cyanoethyl group and the like, and the halogen atom includes chlorine, fluorine and iodine.

The compound used for the transfer sheet of the present invention can be produced, for example, by the following reaction route.

[Wherein, R ² , R ³ , and X have the same meaning as in formula (I). The aniline derivative represented by the general formula (III) is, for example,
In hydrochloric acid water, in the presence of 1.0 to 1.3 times molar ratio of sodium nitrite, 0
After reacting at ５5 ° C. for 1 to 2 hours to diazotize, excess sodium nitrite is decomposed with sulfamic acid to obtain a compound of the general formula (I
A dye represented by the general formula (V) is obtained by performing a coupling reaction with the pyridone represented by the formula (V) at 0 to 5 ° C for 1 to 2 hours.

Then, the obtained compound of the general formula (V) is used, for example, with toluene, xylene, chlorobenzene or the like in an amount of 3 to 7 times by weight based on the compound, and a pyridine having a molar ratio of 0.01 to 1.0 times and a compound of the general formula (VI) are used. The dye represented by the general formula (I) is obtained by reacting at 80 to 100 ° C. for 1 to 3 hours in the presence of a 1.0 to 3.0 molar ratio of the acid chloride shown.

As a method for producing a thermal transfer recording ink using the dye of the present invention, the dye is mixed with an appropriate resin, a solvent, and the like.
The recording ink may be used. As a method of manufacturing the transfer sheet, the transfer sheet can be manufactured by applying a dye ink containing the dye of the present invention on a transfer substrate.

As a thermal transfer method, a transfer sheet is prepared by applying the ink obtained above on a suitable substrate, and the sheet is superimposed on a recording medium, and then heated and heated by a thermal recording head from the back of the sheet. A method of pressing can be used, in which case the dye on the sheet is transferred onto the recording medium.

As the resin for adjusting the above ink, those used in ordinary printing inks may be used, and rosin, phenol, xylene, petroleum, vinyl, polyamide, alkyd, nitrocellulose, and alkyl An oil-based resin such as celluloses or an aqueous resin such as maleic acid, acrylic acid, casein, shellac, glue and the like can be used.

In addition, as a solvent for adjusting the ink, methanol,
Alcohols such as ethanol, propanol and butanol; cellosolves such as methyl cellosolve and ethyl cellosolve; aromatics such as benzene, toluene and xylene; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone and cyclohexanone , Ligroin, cyclohexane, hydrocarbons such as kerosene, dimethylformamide and the like can be used,
When an aqueous resin is used, water or a mixture of water and the above-mentioned solvents can be used.

Substrates to which the ink is applied include condenser paper, tissue paper such as glassine paper, polyester, polyamide,
A plastic film having good heat resistance, such as polyimide, is suitable. However, these substrates have a thickness of about 5 to 50 μm in order to improve the efficiency of heat transfer from the thermal recording head to the dye.

As the recording medium, for example, polyethylene, polyolefin resin such as polypropylene, polyvinyl chloride,
Halogenated polymers such as polyvinylidene chloride, vinyl polymers such as polyvinyl alcohol, polyvinyl acetate and polyacrylic ester, polyethylene terephthalate,
Polyester resin such as polybutylene terephthalate,
Polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene with other vinyl monomers, ionomers, cellulose diacetate,
Examples thereof include fibers, woven fabrics, films, sheets, and molded products made of cellulose resins such as cellulose triacetate, polycarbonate, polysulfone, and polyimide.

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

Further, in the present invention, a resin obtained by adding acidic fine particles such as silica gel to the resin is coated on plain paper, impregnated, laminated with a resin film, or specially processed paper subjected to acetylation treatment. 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]

Since the pyridone azo dye represented by the general formula (I) of the present invention has a clear yellow color, for example, the following structural formula Represented by the magenta color dye and the following structural formula, Suitable for obtaining a full color in combination with a cyan dye.

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

〔Example〕

Hereinafter, the present invention will be described specifically with reference to Examples.
This embodiment does not limit the present invention.

 Parts represent parts by weight, and% represents% by weight.

Example 1 20 parts of m-aminophenol was dissolved in 250 parts of a 6.8% hydrochloric acid solution, and 100 parts of ice was added thereto, followed by cooling to 0 to 5 ° C. To the solution was added 44.5 parts of a 30% aqueous nitrous acid solution, and the mixture was stirred at 0 to 5 ° C. for 1 hour to perform diazotization to obtain a diazotized solution. Then 1.5%
It was dissolved in 550 parts of an aqueous sodium hydroxide solution.

Pyridrine compound of the following formula (VI) To 28.9 parts, the diazotized solution obtained above was added dropwise at 0 to 5 ° C,
After adjusting the pH to 4.5 with 30% aqueous sodium hydroxide,
The mixture was stirred at 0 to 5 ° C for 1 hour to perform coupling. The resulting yellow pigment is filtered off, washed with water and dried to give a yellow powder
35.5 parts were obtained.

9.8 parts of the obtained yellow powder were added to 45 parts of toluene, 1 part of pyridine and 6.1 parts of acetic anhydride were further added, and the mixture was heated and stirred at 80 ° C. for 1 hour. Thereafter, the mixture was cooled to 50 ° C., 45 parts of methanol was added, and the mixture was allowed to cool to room temperature. The precipitated solid was separated by filtration, washed with methanol and dried to obtain a yellow pigment (A) represented by the following formula.
5.7 parts were obtained.

Using the obtained compound (A), preparation of an ink, a transfer sheet, and a recording material were prepared as follows, and transfer recording was performed.
The absorption maximum wavelength of the compound in chloroform (λma
x) was 440 nm.

(I) Ink adjustment method 3 parts of the dye of the formula (A) above 4.5 parts of polybutyral resin 46.25 parts of methyl ethyl ketone 46.25 parts of toluene The above-mentioned dye mixture is mixed with a glass conditioner using a paint conditioner for about 30 minutes. The ink was prepared.

(Ii) Transfer sheet preparation method Using a gravure proofing machine (plate depth 30 μm), apply the above ink to a 9 μm-thick polyethylene terephthalate film that has been heat-treated on the back so that the dry coating amount is 1.0 g / m ^2. And dried.

(Iii) Preparation of recording material Polyester resin (vylon 103 Toyobo Tg = 47 ° C) 0.8 part EVA polymer plasticizer (Elvaloy 741p Mitsui / Dupont Polychemical Tg = -32 ° C) 0.2 part Amino-modified silicone (KF -857 Shin-Etsu Chemical Co., Ltd. 0.04 parts Epoxy-modified silicone (KF-103 Shin-Etsu Chemical Co., Ltd.) 0.04 parts Methyl ethyl ketone / toluene / cyclohexane (weight ratio 4: 4: 2) 9.0 parts Mix and adjust the coating liquid. , Bar Coater (RK Print Coat In) on synthetic paper (Oji Yuka, YUPO FPG # 150)
It was applied at a rate of 4.5 g / m ² when dried using No. 1) manufactured by Struments and dried at 100 ° C. for 15 minutes.

(Iv) Transfer recording The transfer sheet and the recording material are superimposed on each other with the ink-coated surface and the coating liquid-coated surface facing each other.
Recording was performed under the condition of 4.0 milliseconds, and a yellow color record having a color density of 2.7 was obtained.

The color density is measured by Macbeth U.S.A.
It measured using RD-514 type (filter: Wratten No. 58).

 The color density was calculated by the following equation.

Color density = log ₁₀ (Io / I) Io = Intensity of light reflected from a standard white reflector I = Intensity of light reflected from a test object Also, the light resistance test of the obtained record was performed using a xenon fade meter (Suga The test was carried out at a temperature of 63 ± 2 ° C. using a tester manufactured by Test Machine Co., Ltd., but the color hardly changed after irradiation for 40 hours, and the image stability under high temperature and high humidity was excellent.

In addition, the robustness of the obtained recorded image in an atmosphere of 50 ° C
After standing for 48 hours, the sharpness of the image and the coloring when the surface was rubbed with white paper were judged. The sharpness of the image did not change, the white paper was not colored, and the fastness of the recorded image was good. Was.

Example 2 Compound (B) represented by the following formula synthesized by the same method as in Example 1, and compound (C) similarly coupled
Using 1.5 parts each for a total of 3 parts, adjustment of ink, preparation of a transfer sheet and a recording material, and transfer recording were performed, and a yellow color record with a color density of 2.6 was obtained.

These records were subjected to a light resistance test in the same manner as in Example 1. As a result, the records hardly changed, and the stability of images under high temperature and high humidity was excellent.

A fastness test was carried out in the same manner as in Example 1. The sharpness of the image did not change, the white paper was not colored, and the fastness of the recorded image was good.

Examples 3 to 17 Preparation of ink, preparation of a transfer sheet, preparation of a recording material, and transfer recording were performed using the pyridone azo yellow dye shown in Table 1 synthesized according to the same method as that of Example 1, and 1 were obtained.

All of these records were subjected to a light resistance test in the same manner as in Example 1. As a result, the records hardly changed and the stability of images under high temperature and high humidity was excellent.

A fastness test was carried out in the same manner as in Example 1. The sharpness of the image did not change, the white paper was not colored, and the fastness of the recorded image was good.

Comparative Example According to the same method as that of Example 1, the dye of the formula (C)
Preparation of ink, transfer sheet, and recording material were prepared using 3.0 parts.

When the dye of (C) was used alone, some crystals were precipitated on the sheet surface without being completely dissolved in the ink. Transfer recording was performed using this transfer sheet, and the density was measured in the same manner as in Example 1. The result was 0.9. Further, when a light fastness test was performed in the same manner as in Example 1, the recording was discolored.

A fastness test was performed in the same manner as in Example 1. However, the image was unclear, the white paper was colored, and the fastness of the recorded image was poor.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-50-112572 (JP, A) JP-A-51-37919 (JP, A) JP-A-54-38332 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) B41M 5/38-5/40 CA (STN) REG (STN)

Claims (2)

(57) [Claims] (1) (Where R ¹ is X represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, a halogenoalkyl group, an alkoxy group, an aryloxy group, an alkenyloxy group, a cycloalkyloxy group, a halogenoalkyloxy group;
Represents an alkyl group, a cycloalkyl group, an aryl group, a halogenoalkyl group, R2 represents a hydrogen atom, an alkyl group, an alkyl group which may have a substituent, a halogen atom or an alkoxy group, R3 represents a hydrogen atom, It shows an alkyl group or an alkyl group which may have a substituent. Sublimation type dye for thermal recording represented by). (2) (Where R ¹ is X represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, a halogenoalkyl group, an alkoxy group, an aryloxy group, an alkenyloxy group, a cycloalkyloxy group, a halogenoalkyloxy group;
Represents an alkyl group, a cycloalkyl group, an aryl group, a halogenoalkyl group, R2 represents a hydrogen atom, an alkyl group, an alkyl group which may have a substituent, a halogen atom or an alkoxy group, R3 represents a hydrogen atom, It shows an alkyl group or an alkyl group which may have a substituent. A transfer sheet for sublimation-type thermal recording, characterized by comprising at least one or two or more dye components selected from the dye group represented by (1).