JP2623241B2 - Dye for thermal transfer recording and thermal transfer sheet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a dye for sublimation type thermal transfer recording and a thermal transfer sheet.

[Prior Art] Conventionally, there has been a demand for a facsimile printer, a copier, or a technique for color recording of a television image or the like, and a color recording technique using electrophotography, ink jet, thermal transfer, or the like has been studied.

The thermal transfer recording method is considered to be more advantageous than other methods because the maintenance and operation of the apparatus are easy and the apparatus and consumables are inexpensive.

The heat-sensitive transfer method includes a heat transfer method in which a transfer sheet having a heat-meltable ink layer formed on a base film is heated by a heat-sensitive head to melt the ink and transfer-record on a recording medium; There is a sublimation method in which a transfer sheet on which an ink layer containing a sublimable dye is formed is heated by a thermal head to sublimate the dye and transfer recording is performed on a recording medium. Since the amount of sublimation transfer of the dye can be controlled by changing the applied energy, it is considered that gradation recording becomes easy and it is particularly advantageous for full-color recording.

In the sublimation type thermal transfer recording, the sublimable dye used in the transfer sheet greatly affects the speed of the transfer recording, the image quality of the recorded matter, the storage stability, and is very important, and satisfies the following conditions. There is a need to.

Sublimation easily under the operating conditions of the thermal recording head.

Do not thermally decompose under the operating conditions of the thermal recording head.

Having a favorable hue in color reproduction.

Large molecular extinction coefficient.

Stable against heat, light, moisture, chemicals, etc.

Easy synthesis.

Excellent ink suitability.

Heretofore, a dye satisfying all of the above conditions has not been found, and a magenta dye in particular has various drawbacks and no satisfactory dye has been found.

[Problems to be Solved by the Invention] An object of the present invention is to provide a magenta dye that satisfies all of the above conditions and a thermal transfer sheet using the same.

[Means for Solving the Problems] The present invention provides the following general formula [1] (However, in the above formulas, R represents a cyano group, an alkoxycarbonylalkyl group, a substituted alkoxycarbonyl group, R ¹ and R ² are allyl, alkyl group of C ₁ -C _8, a C ₇ -C ₈ C ₂ -C ₈ substituted with an aralkyl group, a C ₃ -C ₈ alkoxyalkyl group, a hydroxyl group, a halogen atom or a cyano group
X represents a hydrogen atom, a methyl group, a methoxy group, a formylamino group, an alkylcarbonylamino group, an alkylsulfonylamino group, or an alkoxycarbonylamino group; and Y represents a hydrogen atom, a methyl group, a methoxy group, or a halogen atom. Represents an atom. A heat-sensitive transfer sheet having a dicyanoimidazole azo dye represented by the formula (1) and a colorant layer containing the dye on a base film.

The method for producing the above-mentioned dye of the present invention includes, for example, the following structural formula [II] Is diazotized according to a conventional method to give a 2-amino-4,5-dicyanoimidazole represented by the following general formula [III]: (Wherein X, Y, R ¹ and R ² are the same as defined above) and obtained by coupling with an aniline represented by the following general formula [IV]: (Wherein X, Y, R ¹ and R ² are the same as defined above) to the azo compound represented by the following general formula [V] RZ... [V] (where Z is a chlorine atom, a bromine atom , Iodine atom, and R is the same as defined above).

When R is a β-cyanoethyl group or β- (alkoxycarbonyl) ethyl group, acrylonitrile or the following general formula [VI] CH ₂ CHCH—COOR ³ (wherein R ³ is a C ₁ -C ₈ alkyl group; (Representing a substituted alkyl group of C _{1 to} C ₈ )).

Specific examples of the dye of the general formula [I] of the present invention include:
Examples include those shown in Examples, but are not limited thereto.

Particularly preferred are, in the general formula [I], wherein R is a cyanomethyl group, a β-cyanoethyl group, an alkoxycarbonylmethyl group having a C _{1 to} C ₈ alkoxy group, C ₁
Represents a β- (alkoxycarbonyl) ethyl group having a C ₈ -alkoxy group, wherein R ¹ and R ² are an allyl group, a C ₁ -C ₈ alkyl group, a C ₇ -C ₈ aralkyl group, a C ₃ -C _{8 8} alkoxyalkyl group, a hydroxyl group, C ₂ -C ₈ substituted by a halogen atom or a cyano group
Represents an alkyl group, X is a hydrogen atom, an alkyl carbonyl amino group having a methyl group, formylamino group, alkyl group of C ₁ -C _4, Y can be cited dyes represent a hydrogen atom.

The heat-sensitive transfer sheet of the present invention prepares an ink by dissolving or dispersing the dye of the present invention together with a binder in a medium in the form of fine particles, applying the ink on a base film, and drying the base film. A color material layer is formed thereon.

As a binder for preparing the ink, cellulose-based,
Examples include water-soluble resins such as acrylic acid and starch, acrylic resins, methacrylic resins, organic solvents such as polystyrene, polycarbonate, polysulfone, polyethersulfone, ethylcellulose, and acetylcellulose, and resins soluble in water.

As a medium for preparing the ink, in addition to water, alcohols such as methyl alcohol, isopropyl alcohol and isobutyl alcohol, cellosolves such as methyl cellosolve and ethyl cellosolve, aromatics such as toluene, xylene and chlorobenzene, ethyl acetate, Esters such as butyl acetate, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; chlorinated solvents such as methylene chloride, chloroform and trichloroethylene; ethers such as tetrahydrofuran and dioxane; N, N-dimethylformamide; Organic solvents such as methylpyrrolidone can be mentioned.

In addition to the above components, organic and inorganic non-sublimable fine particles, a dispersant, an antistatic agent, an antiblocking agent, an antifoaming agent, an antioxidant, a viscosity modifier, etc. are added to the above ink as required. can do.

As the base film to which the ink for preparing the transfer sheet is applied, thin paper such as condenser paper and glassine paper, and a heat-resistant plastic film such as polyester, polyamide and polyimide are suitable. For example, a range of 3 to 50 μm can be mentioned.

As a method of applying the ink to the base film, a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, or the like can be used, and the thickness of the applied layer of the ink ranges from 0.1 to 5 μm after drying. (Yuji Harazaki, Maki Shoten 19)
Published in 1979, "Coating method".

[Action] Since the dicyanoimidazole azo dye of the present invention represented by the general formula [I] has a vivid magenta color, full color recording with good color reproducibility can be obtained by combining it with an appropriate yellow or cyan color. Suitable for getting
In addition, since it easily sublimates and has a large molecular extinction coefficient, high-speed recording with high color density can be obtained without imposing a large burden on the thermal head. Further, since it is stable against heat, light, moisture, chemicals, etc., it does not undergo thermal decomposition during transfer recording, and the obtained recording has excellent storage stability. In addition, since the dye has good solubility in an organic solvent and good dispersibility in water, it is easy to prepare a high-concentration ink that is uniformly dissolved or dispersed. A transfer sheet uniformly applied at a high concentration can be obtained. Therefore, by using these transfer sheets, it is possible to obtain good recording of uniformity and color density.

The heat-sensitive transfer sheet of the present invention can use not only a thermal head but also an infrared ray, a laser beam or the like as a heating means.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the examples do not limit the present invention.

Example 1 a) Preparation of ink (Maximum absorption in chloroform: 558 nm) Dicyanoimidazole azo dye 10 g Cellulose acetate (L-30, manufactured by Daicel Chemical Industries, Ltd.) 10 g Methyl ethyl ketone 80 g The mixture having the above composition was treated with a paint conditioner for 10 minutes to prepare an ink. Was.

b) Preparation of transfer sheet The above ink was applied to a bar coater (RK Print Coat Instru
Condenser paper (10μm thick) using No.1 manufactured by ments
The resultant was coated and dried (dry film thickness: about 1 μm) to obtain a transfer sheet.

c) Transfer recording The ink-coated surface of the transfer sheet was superimposed on a recording medium and recorded using a thermal head under the following conditions, and a clear magenta color was recorded.
Records of 30 uniform color densities could be obtained.

Recording conditions Cotton density in main scan and sub scan: 8 dots / mm Recording power: 0.25 W / dot Heating time of head: 10 msec The recording medium is a 34% by weight saturated polyester aqueous dispersion (manufactured by Toyobo Co., Ltd.) , Vylonal MD-1200,
(Product name) 10g and silica (manufactured by Nippon Silica Industry Co., Ltd., N
A solution prepared by mixing 1 g of ipsil E 220A (trade name) was coated on polypropylene synthetic paper (200 μm thick) with a bar coater (RK Prin
t Coat Instruments Co., Ltd., No. 3), applied and dried.

Color density, manufactured by Macbeth, USA, Densitometer RD
The measurement was carried out using Model -514 (filter: Ratten No. 58).

A light resistance test of the obtained recording was carried out using a carbon arc fade meter (manufactured by Suga Test Instruments Co., Ltd.) (black panel temperature: 63 ± 2 ° C.). After irradiation for 40 hours, almost no discoloration was observed. Further, the transfer sheet and the recording were stable against heat and moisture, and had excellent storage stability in a dark place.

Example 2 Preparation of an ink, preparation of a transfer sheet, and transfer recording were performed in the same manner as in Example 1 by using the dyes shown in Table 1 in place of the dyes used in Example 1, and the results were shown in Table 1 respectively. A clear magenta color record with the indicated color density could be obtained.

The results of the light resistance test of the obtained recording and the storage stability test of the transfer sheet and the recording in a dark place were good.

[Effects of the Invention] As described above, by using the dye for thermal transfer recording and the thermal transfer sheet of the present invention, a clear image of high density, magenta color, and stable to heat and moisture, and A transfer image with high light resistance can be formed.

Claims (2)

(57) [Claims] 1. A compound represented by the following general formula [I] (However, in the above formulas, R represents a cyano group, an alkoxycarbonylalkyl group, a substituted alkoxycarbonyl group, R ¹ and R ² are allyl, alkyl group of C ₁ -C _8, a C ₇ -C ₈ C ₂ -C ₈ substituted with an aralkyl group, a C ₃ -C ₈ alkoxyalkyl group, a hydroxyl group, a halogen atom or a cyano group
X represents a hydrogen atom, a methyl group, a methoxy group, a formylamino group, an alkylcarbonylamino group, an alkylsulfonylamino group, or an alkoxycarbonylamino group; and Y represents a hydrogen atom, a methyl group, a methoxy group, or a halogen atom. Represents an atom. ) A dye for thermal transfer recording characterized by the following. 2. The following general formula [I] on a base film: (Wherein in the above formula, R represents a cyanoalkyl group, an alkoxycarbonylalkyl group, a substituted alkoxycarbonyl group, R ¹ and R ² are allyl, alkyl group of C ₁ -C _8, aralkyl C ₇ -C ₈ C ₂ -C ₈ substituted with a group, a C ₃ -C ₈ alkoxyalkyl group, a hydroxyl group, a halogen atom or a cyano group
X represents a hydrogen atom, a methyl group, a methoxy group, a formylamino group, an alkylcarbonylamino group, an alkylsulfonylamino group, or an alkoxycarbonylamino group; and Y represents a hydrogen atom, a methyl group, a methoxy group, or a halogen atom. Represents an atom. A heat-sensitive transfer sheet comprising a coloring material layer containing a dicyanoimidazole azo dye represented by the following formula: