JPH01263082A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer sheet using a magenta coloring matter which is easily sublimed under the operating conditions of a thermal recording head, stable to heat, light, moisture, chemicals and the like and excellent in the property for making an ink therefrom, by providing a coloring material layer comprising a specified benzothiazolazo coloring matter on a base film. CONSTITUTION:A thermal transfer sheet has a coloring material later comprising a benzothiazolazo coloring matter of general formula [I]. The transfer sheet is produced by dissolving or finely dispersing the coloring matter in a medium together with a binder to prepare an ink, applying the ink to a base film, and drying the applied ink to provide the coloring material layer. The benzothiazolazo coloring matter has a clear magenta color, and is suitable for achieving full-color recording with favorable color reproduction properties by combining it with appropriate yellow and cyan colors. The benzothiazolazo coloring matter can be easily sublimed, enabling high-speed recording with high color density. Further, the coloring matter is stable to heat, light, moisture, chemicals and the like, so that recorded images obtained have excellent preservability and light resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat-sensitive transfer sheet, particularly a transfer sheet used for sublimation-type heat-sensitive transfer recording.

(Conventional technology) Conventionally, there has been a demand for technology for color recording facsimile printers, copying machines, television images, etc., and electrophotography,
Color recording technologies using 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.

The thermal transfer method involves forming a heat-melting tactile ink layer on the base film! The transfer sheet is heated by a thermal head to melt the ink and transferred onto the recording medium, and the transfer sheet is formed with an ink layer containing a sublimable dye on a base film. There is a sublimation method, in which the dye is sublimated by heating with a head and then transferred and recorded onto the recording medium, but with the sublimation method, the amount of sublimation and transfer of the dye can be controlled by changing the energy given to the thermal head. Gradation recording becomes easier, and it 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 the thermal recording head.

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

■ It 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 suitability for ink production.

■ No safety and health problems.

There is no other dye that satisfies all of the above conditions.

(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 has the following general formula CI group, acyl group, acylamino group, alkylsulfonyl group, aminesulfonyl group, aminocarbonyl group, alkylaminesulfonyl group,
Represents a benzene ring which may have an alkylaminocarbonyl group, a thiocyano group, or a hydrogen atom, a lower alkyl group, a formylamino group, a substituted or unsubstituted alkylcarbonylamino group, a benzoylamino group, a substituted or unsubstituted represents a substituted 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, R1 and R2 represent a hydrogen atom substituted or unsubstituted alkyl group, an allyl group The gist of the invention is a heat-sensitive transfer sheet characterized by having a coloring material layer containing a benzothiazole azo dye represented by (or a substituted or unsubstituted aryl group).

The benzothiazole azo dye used in the thermal transfer sheet of the present invention will be described in detail below. Specific examples of A, X, Y, R' and R2 in general formula (1) include the following. Examples include branched alkyl groups,
Substituted alkyl groups include 2-hydroxyethyl group, 3
-Hydroxypropyl group, Hiro-hydroxybutyl group, 2
-hydroxy-substituted alkyl groups such as -hydroxy-propyl groups, carboxymethyl groups, λ-carboxyethyl groups,
Carboxy-substituted alkyl groups such as 3-carboxypropyl groups, cyano-substituted alkyl groups such as cocyanoethyl groups, amine-substituted alkyl groups such as -mono-aminoethyl groups,
Alkyl groups substituted with nitrogen atoms such as 2-chloroethyl group, 3-chloropropyl group, 2-chloro-propyl group, 2,2.2-trifluoroethyl group, benzyl group, 2-
Phenyl-substituted alkyl groups such as phenylethyl groups 2-
Methoxyethyl group, 2-ethoxyethyl M%2-(n)
Propoxyethyl group, -2-(iso)propoxyethyl group, 2-(n)butoxyethyl group, co(iso)
) Butoxyethyl group, 2-(2-ethyl-hexyloxy)ethyl group, 3-methoxypropyl group, ≠-methoxybutyl group, alkoxy-substituted alkyl group such as 2-methoxypropyl group, λ-(2-methoxyethoxy) Ethyl group, x-(2-ethoxyethoxy)ethyl group, 2- (2
-(n)propoxyethoxy)ethyl group 1. z −(,
2-(iso)propoxyethoxy)ethyl group, ' -
(2(n)butoxyethoxy)ethyl group, ' ”-(2
-(iso)butoxyethoxy)ethyl group, 2-12-
(2-Ethylhexyloxy)ethoxy)ethyl group, an alkoxyalkoxy-substituted alkyl group,! -acetyloxyethyl group, coprobionyloxyethyl group,
x-(n) butyryloxyethyl group, 2-(iso)butyryloxyethyl group, cotrifluoroacetyloxyethyl group, acyloxy group-substituted alkyl group such as benzoyloxyethyl group, methoxycarbonylmethyl group,
Ethoxycarbonylmethyl group, (n) propoxycarbonylmethyl group, (iso) propoxycarbonylmethyl group, (n) butoxycarbonylmethyl group, (iso) butoxycarbonylmethyl group, coethylhexyloxycarbonylmethyl group, benzyloxycarbonylmethyl group , furfuryloxycarbonylmethyl group, 2-methoxycarbonylethyl group, coethoxycarbonylethyl group, -2-(n)propoxycarbonylethyl group%2-
(iso)propoxycarbonylethyl group, -2-(n
) butoxycarbonylethyl group, J-(iso)
7” Toxycarbonylethyl group 5x-(2-ethylhexyloxycarbonyl)ethyl group, cobenzyloxyproponylethyl group, cofurfuryloxyproponylethyl group, optionally substituted alkoxycarbonyl-substituted alkyl group, 2-methoxy Carbonyloxyethyl group, !-ethoxycarbonyloxyethyl a%2
-(n) propoxycarbonyloxyethyl group, co-(
iso) propoxycarbonyloxyethyl group, 2-(
n) Butoxycarbonyloxyethyl group, co-(iso
) Butoxycarbonyloxyethyl group 1,! -(2-ethylhexyloxycarbonyloxy)ethyl group, 2-
Examples include substituted alkyl groups such as benzyloxycarbonyloxyethyl group and 2-furfuryloxycarbonyloxyethyl group, and heterocyclic substituted alkyl groups such as furfuryl group and tetrahydrofurfuryl group. . Examples of the aryl group represented by R1 and R2 include 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 halogen atoms represented by X and Y in general formula (IJ) include fluorine atom, chlorine atom, and bromine atom. Substituted or unsubstituted alkylcarbonylamino group represented by X in general formula CI) include acetylamino The substituted or unsubstituted alkoxycarbonylamino group represented by X, propionylamino group, (n) butyrylamino group, methoxycarbonylamino group, ethoxycarbonylamino group, (n) propoxycarbonylamino group, (iso) propoxy carbonylamino group, (n) butoxycarbonylamino group, (i
so) butoxycarbonylamino group, furfuryloxycarbonylamino group, benzyloxycarbonylamino group, tetrahydrofurfuryloxycarbonylamino group, and the like. The alkoxy group represented by Y in general formula (I) includes methoxy group, ethoxy group, (n
) propoxy group, (iso) propoxy group, (n) butoxy group, (iso) butoxy group, λ-ethylhexyloxy group, these two groups may be substituted, co-chloro/toxy group, co-chloro/toxy group, etc. Methoxyethoxy group, coethoxyethoxy group, -2
Examples include -(n) propoxyethoxy group, -benzyloxyethoxy group, 2-furfuryloxyethoxy group, 2-tetrahydrofurfuryloxyethoxy group, furfuryloxy group, and tetrahydrofurfuryloxy group.

Examples of the lower alkyl group represented by X and Y in general formula (I) include C1 to C4 linear or branched alkyl groups. In the general formula (I), fluorine atom, chlorine atom, bromine atom, etc. can be mentioned as the chlorine atom which is a substituent on the benzene ring, and as the alkyl group, 01 to C8 straight chain or branched chain atom can be mentioned. Alkyl groups include methoxy groups, ethoxy groups, (n) propoxy groups, (iso) propoxy groups, (n) butoxy groups, (iso) butoxy groups, etc., and alkoxy carbonyl groups include is a methoxycarbonyl group, an ethoxycarbonyl group, (n) a propoxycarbonyl group, an (iso) propoxycarbonyl group,
(n) butoxycarbonyl group, (iso)butoxycarbonyl group, (n) hexyloxycarbonyl group, coethylhexyloxycarbonyl group, etc.; examples of the acyl group include acetyl group, propionyl group, benzoyl group, etc. Examples of the acylamino group include an acetylamino group, a propionylamino group, a benzoylamino group, etc., an alkylsulfonyl group, an ethylsulfonyl group, an ethylsulfonyl group, and an example of the alkylaminesulfonyl group include 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 M, N, N
-diethylaminosulfonyl group, N, N-cy(n)
7' lobylaminosulfonyl group, N,N-di(iso)
Examples of alkylaminocarbonyl groups include propylaminosulfonyl group, N,N-di(n)butylaminosulfonyl group, and alkylaminocarbonyl group, N-methylaminocarbonyl group, N-ethylaminocarbonyl group, N-(n)propylaminocarbonyl group, etc. carbonyl 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)propylamino carbonyl group, N,N-di(n)butylaminocarbonyl group,
Examples include N,N-di(iso)butylaminocarbonyl group.

Among the benzothiazole azo dyes represented by the general formula (1), dyes particularly suitable for use in the heat-sensitive transfer sheet of the present invention are those in which R1 and R2 are C1 to C8 alkyl groups, hydroxyethyl groups, and cyanethyl groups. , trifluoroethyl group, chloroethyl group, phenylalkyl group,
C9-C8 alkoxyalkyl Ti, C4-C8 acyloxyalkyl group, 03-CI. Alkoxycarbonylalkyl group, 04-C engineering. A group selected from an alkoxycarbonyloxyalkyl group and an allyl group is preferable.

In addition, X is a C2-C4 alkylcarbonylamino group, a trifluoroacetylamino group, a 02-C6 alkoxycarbonylamino group, a methyl group, a formylamino group,
A group selected from halogen atoms (especially chlorine atoms or fluorine atoms) is preferable, and Y is a group selected from C□ to C4
The group is preferably selected from an alkoxy group, a methyl group, a hydrogen atom, and a chlorine atom (particularly a chlorine atom or a fluorine atom). The embedding is unsubstituted, or the substituent is a chlorine atom (particularly a chlorine atom or a fluorine atom), a C□-C4 alkyl group, a C□-C4 alkoxy group, or a C2-C.

Alkoxycarbonyl group, acetyl group, C, or C, alkylsulfonyl group, di(Ct-C4 alkoxy)aminosulfonyl group, di(C1-C4 alkyl)aminocarbonyl group, )'J fluoromethyl group, thiocyano group, nitro group Or preferably, it has a cyano group.

The benzothiazole azo dye represented by the general formula CI) used in the present invention is, for example, Tokuko Shonu≠-306. ! g
It can be produced by a known method as disclosed in Japanese Patent Publication No. Sho≠Yoichi♂750, Japanese Patent Publication Sho≠R-33/3, etc.

The heat-sensitive transfer sheet of the present invention is formed using the above-mentioned dye, but the method is not particularly limited. Usually, the dye is dissolved in a medium or dispersed in the form of fine particles together with a binder. An ink is prepared, and the ink is applied onto a base film and dried to form a coloring 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, AsL polyether sulfone, polyvinyl butyral, polyester, and ethyl cellulose. ,
Examples include organic solvents such as acetylcellulose or water-soluble resins.

In addition to water, media for ink preparation include alcohols such as methyl alcohol, imbutyl alcohol, and imbutyl alcohol, cellosolders such as methyl cellosolve and ethyl cellosolve, aromatics such as toluene, xylene, and chlorobenzene, and acetic acid. Esters such as ethyl and butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl in butyl ketone, and cyclohexanone;
Examples include chlorinated solvents such as methylene chloride, chloroform, and trichloroethylene, ethers such as tetrahydrofuran and dioxane, and organic solvents such as N,N-dimethylformamide and N-methylpyrrolidone. In addition, organic or inorganic non-sublimable fine particles, a dispersant, an antistatic agent, an antiblocking agent, an antifoaming agent, an antioxidant, a viscosity modifier, etc. can be added as necessary.

Base films for applying ink for making transfer sheets include condenser paper, thin paper such as glassine paper, polyester, polycarbonate, polyamide,
Plastic films with good heat resistance such as polyimide and polyaramid are suitable, and their thicknesses can range from 3 to 0 μm.

Among the above base films, polyethylene terephthalate film is particularly advantageous in view 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 the running properties of the thermal head are insufficient. By providing a layer of synthetic resin, it is possible to use a thermal head with improved running performance.

The method of applying the ink to the base film can be carried out using a reverse roll coater, a Krachia coater, a rod coater, an air doctor coater, etc., and the thickness of the ink coating layer after drying is 0.000. It is sufficient to apply the coating within a range of 1 to 58 m. These methods can be easily carried out, for example, according to the method described in "Coating Method" by Yuji Harasaki, published by Maki Shoten in 1972.

Furthermore, the thermal transfer sheet of the present invention uses not only a thermal head but also infrared light,
It can also be applied when using laser light or the like.

Further, the thermal transfer sheet of the present invention can be used as a sheet for electrical thermal transfer by using a sheet having an electrically conductive thin film layer on a base film such as the above-mentioned plastic film, and coating it with ink by the above method. It can also be used.

(Actions and effects of the invention) The general formula CI used in the heat-sensitive transfer sheet of the invention
The benzothiazole azo dye shown in Since it sublimates easily and has a large molecular extinction coefficient, it is possible to obtain high-speed recording with high color density without placing a large burden on the thermal head. 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 pigment has good solubility in organic solvents and dispersibility in water, it is easy to prepare a highly concentrated ink that is uniformly dissolved or dispersed. It is possible to obtain a heat-sensitive transfer sheet on which is coated uniformly and at a high concentration. Therefore,
By using these heat-sensitive transfer sheets, recordings 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.

Examples/a) Preparation of ink The above azo dye? Polysulfone resin 10f Ri C10 benzene 100? Total // Evening? Needel P-/700 (trade name) manufactured by Kunissan Chemical Industry Co., Ltd. A mixture having the above composition was treated with a paint conditioner for 10 minutes to prepare an ink.

b) Preparation of transfer sheet The above ink was applied to a polyethylene terephthalate film (6 μm
The transfer sheet was coated on the transfer sheet (with a dry film thickness of approximately 1 μm) and dried. In addition, the heat-resistant lubricity treatment of the polyethylene terephthalate film is performed by adding parts by weight of a polycarbonate resin having a repeating structural unit shown by the following formula to the polyethylene terephthalate film, parts by weight of a phosphate ester surfactant (
This was carried out by applying a solution consisting of NIBLY SURF A-20♂B (trade name: Daiichi Kogyo Seiyaku Co., Ltd. product) and toluenta/parts by weight, and drying (dry film thickness: about 03 μm).

C) Preparation of image receptor Saturated polyester resin (product name: TP-,2,1!(
7゜ Nippon Gosei Co., Ltd. product) io part, amine-modified silicone (product name: KF 393, Shin-Etsu Chemical Co., Ltd. product) Q,! parts, 775 parts of methyl ethyl keto, 1 xylene
Synthetic paper (product name: YUPO FPG/J-
0, Oji Yuka Co., Ltd. product) applied with a wire bar and dried to a dry film thickness of approx. μm)s further in the oven
An image receptor was prepared by heat treatment at 0° C. for 3θ minutes.

d) Transfer recording The ink-applied surface of the above 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 record with a clear magenta color and uniform color density. .

Recording conditions Linear density of main scanning and sub-scanning: ♂ dot l-/Trm Recording power: o, 2 sw/dot head heating time: 10 msec Color density was determined using a densitometer TR-r, Z7 type, manufactured by Macbeth Corporation in the United States. It was measured using

A light resistance test of the obtained records was carried out using a carbon arc fade meter (manufactured by Suga Test Instruments Co., Ltd.) (black panel temperature 3±2°C), but after irradiation for ti-o time, No discoloration or fading. Furthermore, the transfer sheet and recording were stable against heat and moisture, and had excellent dark storage stability.

Example 2 Ink was prepared, a transfer sheet was prepared, and transfer recording was carried out in the same manner as in Example using the dyes shown in Table 1 instead of the dyes used in Example. 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.

Claims (1)

[Claims] The base film has the following general formula (I) ▲ mathematical formula, chemical formula, table, etc. ▼ (I) (wherein A is a nitro group, a cyano group, a carboxyl group, a halogen atom, an alkyl group, trifluoromethyl group, alkoxy group, alkoxycarbonyl group, acyl group, acylamino group, alkylsulfonyl group, aminosulfonyl group, aminocarbonyl group, alkylaminosulfonyl group,
Represents a benzene ring which may have 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, a benzoylamino group, a substituted or unsubstituted represents an 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, and R^1 and R^2 represent a hydrogen atom, a substituted or unsubstituted alkyl 1. A heat-sensitive transfer sheet comprising a coloring material layer containing a benzothiazole azo dye represented by a benzothiazole group, an allyl group, or a substituted or unsubstituted aryl group.