JPH0462878B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a thermal transfer sheet, and particularly to a transfer sheet used for sublimation type thermal transfer recording. (Prior Art) Conventionally, there has been a demand for technology for color recording facsimile printers, copying machines, television images, etc., and 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 recording onto 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 and record onto the recording medium. Since the amount of sublimation transfer of the dye can be controlled by changing the applied energy, gradation recording becomes easy and is considered to be particularly advantageous for full color recording. In thermal transfer recording using the sublimation method, the sublimable dye used in the transfer sheet is extremely important as it has a large effect on the speed of transfer recording, the image quality of the recorded material, and the storage stability.The following conditions must be met. It is necessary to fulfill the requirements. Easily sublimated under the operating conditions of a thermal recording head. Do not thermally decompose under the operating conditions of the thermal recording head. Must have a favorable hue in terms of color reproduction. High molecular extinction coefficient. Stable against heat, light, moisture, chemicals, etc. Easy to synthesize. Excellent ink suitability. There should be no safety and health problems. No dye has been found to date that satisfies all of the above conditions, and magenta dyes in particular have various drawbacks and have not yet been found to be satisfactory. (Problems to be Solved by the Invention) An object of the present invention is to provide a thermal transfer sheet characterized by using a magenta dye that satisfies all of the above conditions. (Means for Solving the Problems) The present invention provides the following general formula [] (In the formula, A is a nitro group, cyano group, carboxyl group, halogen atom, alkyl group, trifluoromethyl group, alkoxy group, alkoxycarbonyl group, acyl group, acylamino group, alkylsulfonyl group, aminosulfonyl group, aminocarbonyl group , represents a benzene ring which may have an alkylaminosulfonyl group, an alkylaminocarbonyl group, a thiocyano group, and X is a hydrogen atom, a lower alkyl group, a formylamino group, a substituted or unsubstituted alkylcarbonylamino group, benzoyl represents an amino group, a substituted or unsubstituted alkoxycarbonylamino group, or a halogen atom; Y represents a hydrogen atom, a lower alkyl group, a substituted or unsubstituted alkoxy group, or a halogen atom; R ¹ and R ² represent a hydrogen atom, a substituted or an unsubstituted alkyl group, an allyl group, or a substituted or unsubstituted aryl group); It is. The benzothiazole azo dye used in the heat-sensitive transfer sheet of the present invention will be explained in detail below.
Specific examples of A, X, Y, R ¹ and R ² in the general formula () include the following. Examples of the alkyl group represented by R ¹ and R ² in the general formula () include a C ₁ to C ₈ linear or branched alkyl group, and examples of the substituted alkyl group include a 2-hydroxyethyl group, Hydroxy-substituted alkyl groups such as 3-hydroxypropyl group, 4-hydroxybutyl group, 2-hydroxy-propyl group, carboxy-substituted alkyl group such as carboxymethyl group, 2-carboxyethyl group, 3-carboxypropyl group, 2-cyanoethyl cyano-substituted alkyl groups such as groups, amino-substituted alkyl groups such as 2-amino-ethyl groups, 2-chloroethyl groups, 3
-chloropropyl group, 2-chloro-propyl group,
Halogen-substituted alkyl groups such as 2,2,2-trifluoroethyl groups, phenyl-substituted alkyl groups such as benzyl groups, 2-phenylethyl groups, 2-
Methoxyethyl group, 2-ethoxyethyl group, 2-
(n) propoxyethyl group, 2-(iso)propoxyethyl group, 2-(n) butoxyethyl group, 2-
Alkoxy-substituted alkyl groups such as (iso)butoxyethyl group, 2-(2-ethyl-hexyloxy)ethyl group, 3-methoxypropyl group, 4-methoxybutyl group, 2-methoxypropyl group, 2-(2-ethyl-hexyloxy)ethyl group,
-methoxyethoxy)ethyl group, 2-(2-ethoxyethoxy)ethyl group, 2-(2-(n)propoxyethoxy)ethyl group, 2-(2-(iso)propoxyethoxy)ethyl group, 2-(2-(n)propoxyethoxy)ethyl group, 2-(2-(n)propoxyethoxy)ethyl group, -(n)butoxyethoxy)ethyl group, 2-(2-(iso)butoxyethoxy)ethyl group, alkoxyalkoxy-substituted alkyl group such as 2-{2-(2-ethylhexyloxy)ethoxy}ethyl group, 2-acetyl Oxyethyl group, 2-propionyloxyethyl group, 2-(n)butyryloxyethyl group, 2-
(iso) an acyloxy-substituted alkyl group such as a butyryloxyethyl group, a 2-trifluoroacetyloxyethyl group, a benzoyloxyethyl group, a methoxycarbonylmethyl group, an ethoxycarbonylmethyl group, (n) a propoxycarbonylmethyl group,
(iso) propoxycarbonylmethyl group, (n) butoxycarbonylmethyl group, (iso) butoxycarbonylmethyl group, 2-ethylhexyloxycarbonylmethyl group, benzyloxycarbonylmethyl group, furfuryloxycarbonylmethyl group, 2
-methoxycarbonylethyl group, 2-ethoxycarbonylethyl group, 2-(n) propoxycarbonylethyl group, 2-(iso)propoxycarbonylethyl group, 2-(n) butoxycarbonylethyl group, 2-(iso)butoxycarbonyl Ethyl group, 2
-(2-ethylhexyloxycarbonyl)ethyl group, 2-benzyloxycarbonylethyl group,
Optionally substituted alkoxycarbonyl-substituted alkyl groups such as 2-furfuryloxycarbonylethyl group, 2-methoxycarbonyloxyethyl group, 2-ethoxycarbonyloxyethyl group,
2-(n) propoxycarbonyloxyethyl group,
2-(iso)propoxycarbonyloxyethyl group, 2-(n)butoxycarbonyloxyethyl group, 2-(iso)butoxycarbonyloxyethyl group, 2-(2-ethylhexyloxycarbonyloxy)ethyl group, 2-benzyloxy Examples include optionally substituted alkoxycarbonyloxy-substituted alkyl groups such as carbonyloxyethyl group and 2-furfuryloxycarbonyloxyethyl group, and heterocyclic-substituted alkyl groups such as furfuryl group and tetrahydrofurfuryl group. The aryl group represented by R ¹ and R ² includes a phenyl group or a phenyl group having a substituent such as a fluorine atom, a base atom, a methyl group, or a methoxy group. Examples of the halogen atom represented by X and Y in the general formula () include a fluorine atom, a chlorine atom, and a bromine atom. The substituted or unsubstituted alkylcarbonylamino group represented by X in general formula () includes acetylamino group, propionylamino group, (n) butyrylamino group, (iso)
Examples include a butyrylamino group and a trifluoroacetylamino group. The substituted or unsubstituted alkoxycarbonylamino group represented by butoxycarbonylamino group, (iso)butoxycarbonylamino group,
Examples include furfuryloxycarbonylamino group, benzyloxycarbonylamino group, and tetrahydrofurfuryloxycarbonylamino group. The alkoxy group represented by Y in the general formula () is a methoxy group, an ethoxy group, (n)
Propoxy group, (iso) propoxy group, (n) butoxy group, (iso) butoxy group, 2-ethylhexyloxy group, these groups may be substituted, 2-chloroethoxy group, 2-methoxy group, etc. Ethoxy group, 2-ethoxyethoxy group, 2-(n)
Propoxyethoxy group, 2-(iso)propoxyethoxy group, 2-(n)butoxyethoxy group, 2-
(iso)butoxyethoxy group, 2-benzyloxyethoxy group, 2-furfuryloxyethoxy group,
2-tetrahydrofurfuryloxyethoxy group,
Examples include furfuryloxy group and tetrahydrofurfuryloxy group. The lower alkyl group represented by X and Y in general formula () is
Examples include C ₁ to C ₄ linear or branched alkyl groups. Examples of the halogen atom, which is a substituent on the benzene ring A in the general formula (), include fluorine atom, chlorine atom, and bromine atom, and examples of the alkyl group include C ₁ to C ₈ linear or branched chain atoms. Examples of alkyl groups include methoxy groups, ethoxy groups, (n) propoxy groups,
(iso) propoxy group, (n) butoxy group, (iso)
Examples include butoxy groups, and alkoxycarbonyl groups include methoxycarbonyl groups, ethoxycarbonyl groups, (n) propoxycarbonyl groups,
(iso) propoxycarbonyl group, (n) butoxycarbonyl group, (iso) butoxycarbonyl group,
(n) Hexyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, etc., and examples of the acyl group include acetyl group, propionyl group,
Examples of the acylamino group include an acetylamino group, propionylamino group, and benzoylamino group; examples of the alkylsulfonyl group include a methylsulfonyl group and an ethylsulfonyl group; examples of the alkylaminosulfonyl group include a benzoyl group; , N-methylaminosulfonyl group, N-ethylaminosulfonyl group, N-
(n) Propylaminosulfonyl group, N-(iso)
Propylaminosulfonyl group, N-(n)butylaminosulfonyl group, N-(iso)butylaminosulfonyl group, N,N-dimethylaminosulfonyl group, N,N-diethylaminosulfonyl group, N,
N-di(n)propylaminosulfonyl group, N,
N-di(iso)propylaminosulfonyl group, N,
Examples of the alkylaminocarbonyl group include N-di(n)butylaminosulfonyl group,
N-methylaminocarbonyl group, N-ethylaminocarbonyl group, N-(n) propylaminocarbonyl group, N-(iso)propylaminocarbonyl group, N-(n) butylaminocarbonyl group, N-
(iso)butylaminocarbonyl group, N,N-dimethylaminocarbonyl group, N,N-diethylaminocarbonyl group, N,N-di(n)propylaminocarbonyl group, N,N-di(iso)propylaminocarbonyl group , N,N-di(n)butylaminocarbonyl group, N,N-di(iso)butylaminocarbonyl group, and the like. Among the benzothiazole azo dyes represented by the above general formula [], the dyes particularly suitable for use in the heat-sensitive transfer sheet of the present invention are as R ¹ and R ² .
C1 _{- C8} alkyl group, hydroxyethyl group, cyanoethyl group, trifluoroethyl group, chloroethyl group, phenylalkyl group, _C2 - _C8 alkoxyalkyl group, _C4 - _C8 acyloxyalkyl group,
_C3 ~ _C10 alkoxycarbonylalkyl group, C4 _~
It is preferably a group selected from a C ₁₀ alkoxycarbonyloxyalkyl group and an allyl group. In addition, as X, C ₂ - C ₄ alkylcarbonylamino group, trifluoroacetylamino group, C ₂ -
_C5 alkoxycarbonylamino group, methyl group,
It is preferably a group selected from a formylamino group, a halogen atom (especially a chlorine atom or a fluorine atom), and Y is a C ₁ to C ₄ alkoxy group,
It is preferably a group selected from a methyl group, a hydrogen atom, and a halogen atom (particularly a chlorine atom or a fluorine atom). Ring A is unsubstituted or has a halogen atom (especially a chlorine atom, a fluorine atom), a _C1 - _C4 alkyl group, a _C1 - _C4 alkoxy group, a _C2 - _C9 alkoxy group as a substituent. carbonyl group, acetyl group, C ₁ or C ₂ alkylsulfonyl group, di(C ₁
~C ₄ alkyl) aminosulfonyl group, di(C ₁ ~
It preferably has a C ₄ alkyl) aminocarbonyl group, a trifluoromethyl group, a thiocyano group, a nitro group or a cyano group. The benzothiazole azo dye represented by the general formula [] used in the present invention is, for example,
It can be produced by known methods such as those disclosed in Japanese Patent Publication No. 30628, Japanese Patent Publication No. 45-8750, and Japanese Patent Publication No. 45-3313. The thermal transfer sheet of the present invention is formed using the above dye, but the method is not particularly limited,
Usually, an ink is prepared by dissolving or dispersing a dye in a medium together with a binder in the form of fine particles, and the ink is applied onto a base film and dried to form a color material layer on the base film. Binders for ink preparation include water-soluble resins such as cellulose, acrylic acid, and starch, acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, AS resin,
polyether sulfone, polyvinyl butyral,
Examples include organic solvents such as polyester, ethyl cellulose, and acetyl cellulose, and resins soluble in water. In addition to water, media for ink preparation include 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, tetrahydrofuran,
Examples include ethers such as dioxane, and organic solvents such as N,N-dimethylformamide and N-methylpyrrolidone. In addition to the above ingredients, organic and inorganic non-sublimable fine particles, dispersants, antistatic agents, antiblocking agents, antifoaming agents, antioxidants, viscosity modifiers, etc. are added to the above ink as necessary. can do. Suitable base films for applying ink for producing transfer sheets include thin paper such as condenser paper and glassine paper, and films made of plastics with good heat resistance such as polyester, polycarbonate, polyamide, polyimide, and polyaramid. However, their thickness is 3 to 50μ
A range of m can be mentioned. Among the above base films, polyethylene terephthalate film is particularly advantageous in consideration of mechanical strength, solvent resistance, economic efficiency, and the like. However, in some cases, polyethylene terephthalate film does not necessarily have sufficient heat resistance and runs poorly on thermal heads, so surfactants, highly slippery heat-resistant particles, etc. are added to the opposite side of the coloring material layer. By providing a layer of heat-resistant resin containing heat-resistant resin, it is possible to use a thermal head with improved running properties. The ink can be applied to the base film using a reverse roll coater, gravure coater, rod coater, air doctor coater, etc., and the thickness of the ink coating layer after drying is in the range of 0.1 to 5 μm. All you have to do is apply it. These methods are, for example, written by Yuji Harasaki,
This can be easily carried out according to the method described in "Coating Method" published by Maki Shoten in 1979. Further, the heat-sensitive transfer sheet of the present invention can be applied not only to a thermal head but also to infrared light, laser light, etc. as a heating means when transferring a dye. Further, the thermal transfer sheet of the present invention uses a sheet having a conductive thin film layer in addition to the above-mentioned plastic film as a base film,
It can also be used as an electrical thermal transfer sheet by applying ink using the method described above. (Operations and Effects of the Invention) Since the benzothiazole azo dye represented by the above general formula [] used in the heat-sensitive transfer sheet of the present invention has a clear magenta color, it can be combined with an appropriate yellow color and cyan color. It is suitable for obtaining full-color records with good color reproducibility, and because it sublimes easily and has a large molecular extinction coefficient, it is possible to obtain records with high color density at high speed without placing a large burden on the thermal head. can. Furthermore, since it is stable against heat, light, moisture, chemicals, etc., it does not undergo thermal decomposition during transfer recording, and the resulting recording has excellent storage stability, particularly in terms of light resistance. In addition, since the dye has good solubility in organic solvents and good dispersibility in water,
It is easy to prepare highly concentrated inks that are uniformly dissolved or dispersed, and by using these inks, it is possible to obtain a heat-sensitive transfer sheet on which a dye is uniformly coated at a high concentration. Therefore, by using these heat-sensitive transfer sheets, recording with good uniformity and color density can be obtained. (Examples) The present invention will be specifically explained below with reference to Examples, but these Examples do not limit the present invention. Example 1 a Preparation of ink The above azo dye 5g Polysulfone resin ^* 10g Chlorobenzene 100g Total 115g *Manufactured by Nissan Chemical Industries, Ltd., Udel P-1700 (trade name) A mixture of the above composition was treated with a paint conditioner for 10 minutes to prepare ink. Summer. b. Preparation of transfer sheet The above ink was applied using a wire bar onto a polyethylene terephthalate film (6 μm thick) whose back surface had been treated for heat-resistant slipping, and dried (dry film thickness approximately 1 μm) to obtain a transfer sheet. The heat-resistant and slippery treatment for polyethylene terephthalate film is performed using the following formula. 8 parts by weight of a polycarbonate resin having a repeating structural unit shown by, 1 part by weight of a phosphoric acid ester surfactant (product name: Plysurf A-208B:
This was done by applying a solution consisting of 91 parts by weight of toluene (product of Daiichi Kogyo Seiyaku Co., Ltd.) and drying (dry film thickness approximately 0.5 μm). c Preparation of image receptor 10 parts of saturated polyester resin (product name: TP-220, product of Nippon Gosei Co., Ltd.), 0.5 parts of amino-modified silicone (product name: KF393, product of Shin-Etsu Chemical Co., Ltd.), 15 parts of methyl ethyl ketone, xylene
A liquid consisting of 15 parts is applied to synthetic paper (product name: YUPO
FPG150, a product of Oji Yuka Co., Ltd.) was coated with a wire bar, dried (dry film thickness approximately 5 μm), and further heat-treated at 100°C for 30 minutes in an oven to prepare an image receptor. d Transfer Recording The ink-coated surface of the transfer sheet was placed on the recording medium and recording was performed using a thermal head under the following conditions, and it was possible to obtain a clear magenta record with a uniform color density of 1.15. Recording conditions Main scanning and sub-scanning linear density: 8 dots/mm Recording power: 0.25 W/dot head heating time: 10 msec Color density was measured using a densitometer model TR-927 manufactured by Macbeth Co., USA. 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.), and there was almost no discoloration or fading after 40 hours of irradiation.
Furthermore, the transfer sheet and recording were stable against heat and moisture, and had excellent dark storage stability. Example 2 The dyes shown in Table 1 were used instead of the dyes used in Example 1, and ink preparation, transfer sheet production, and transfer recording were carried out in the same manner as in Example 1. As a result, the results shown in Table 1 were obtained. It was possible to obtain a clear magenta color record with the color density shown in . The results of the light fastness test of the obtained record and the dark storage stability test of the transfer sheet and record were both good.

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Claims (1)

[Claims] 1. The following general formula () is formed on the base film. (In the formula, A is a nitro group, cyano group, carboxyl group, halogen atom, alkyl group, trifluoromethyl group, alkoxy group, alkoxycarbonyl group, acyl group, acylamino group, alkylsulfonyl group, aminosulfonyl group, aminocarbonyl group , represents a benzene ring which may have an alkylaminosulfonyl group, an alkylaminocarbonyl group, or a thiocyano group, and X is a hydrogen atom, a lower alkyl group, a formylamino group, a substituted or unsubstituted alkylcarbonylamino group, or a benzoylamino group. Y represents a hydrogen atom, a lower alkyl group, a substituted or unsubstituted alkoxy group, or a halogen atom, and R ¹ and
A heat-sensitive transfer product characterized by having a coloring material layer containing a benzothiazole azo dye represented by (R ² represents a hydrogen atom, a substituted or unsubstituted alkyl group, an allyl group, or a substituted or unsubstituted aryl group) sheet.