JPH10310716A - Coloring matter for heat-sensitive transfer and heat-sensitive transfer sheet using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new compound useful as a heat-sensitive transfer sheet capable of carrying out the uniform heat-sensitive transfer recording at a high density. SOLUTION: This compound is represented by formula I [Z<1> and Z<2> are each a (substituted)alkyl, etc.; R<1> and R<2> are each an alkoxy, etc.; R<3> and R<4> are each a halogen, etc.; R<5> and R<6> are each allyl, etc.], e.g. a compound represented by formula I in which NZ<1> Z<2> is N(CH3 )2 ; R<1> , R<2> and R<4> are each H; R<3> is (5')-CH3 ; R<5> and R<6> are each C2 H5 . The compound represented by formula I is obtained by reacting a phenolic compound represented by formula II with an aniline-based compound represented by formula III in the presence of an oxidizing agent (e.g. hydrogen peroxide) in an inert solvent (e.g. tetrahydrofuran) under neutral to alkaline conditions and 0-25 deg.C temperature conditions. The resultant coloring matter, together with a binder resin, is dissolved or dispersed in the form of fine particles in a medium to prepare an ink, which is then applied onto a support and dried to afford a heat-sensitive transfer sheet containing the coloring matter layer formed on the support.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet having a dye for thermal transfer and a colorant layer.

[0002]

2. Description of the Related Art Hitherto, color recording techniques such as an electrophotographic system, an ink jet system, and a thermal transfer system have been studied for facsimile machines, copiers and printers. The thermal transfer recording method has many advantages over other methods because the maintenance and operation of the apparatus are easy and the apparatus and consumables are inexpensive.

[0003] The thermal transfer method is a method in which a thermal transfer sheet having a heat-meltable ink layer formed on a base film is heated by a thermal head to melt the ink and transfer and record the image on an image receiving sheet. There is a method in which a thermal transfer sheet having a color material layer containing a heat transferable dye formed on a base film is heated by a thermal head to transfer the dye onto the image receiving sheet. The amount of dye transfer can be controlled by changing the energy applied to the head, so that gradation recording becomes easy, high definition,
This is particularly easy for high-quality full-color recording.

In order to obtain a uniform image by the thermal transfer transfer method, it is necessary that the dye is completely and uniformly dissolved in the color material layer of the thermal transfer sheet to be used. If the solubility of the dye is poor, the dye crystallizes in the color material layer and becomes non-uniform.
When a transfer image is prepared using such a heat-sensitive transfer sheet, transfer of the dye in the crystallized portion to the image receiving layer becomes insufficient, and a uniform image cannot be obtained. Various methods have been studied to solve these problems. For example, Japanese Patent Application Laid-Open No. 63-308072 has been proposed.
Transfer sensitivity, solubility in ink solvent, storage stability of dye in ink, storage stability of dye in colorant layer on thermal transfer sheet, storage stability of dye in image receiving layer on image receiving sheet Further improvements are required in light resistance, image light resistance, and the like.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a blue indoaniline-based thermal transfer dye and a thermal transfer sheet which overcome the above-mentioned problems.

[0006]

The present invention relates to a thermal transfer dye represented by the following general formula (I) and a thermal transfer sheet having a color material layer on a support, wherein the color material layer is The gist of the present invention is a heat-sensitive transfer sheet containing the heat-sensitive transfer dye represented by the general formula (I).

[0007]

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(Wherein Z ¹ and Z ² each independently represent an alkyl group, a cycloalkyl group, an aryl group which may have a substituent or a heterocyclic group which may have a substituent Or combine with each other to form a heterocyclic group,
R ¹ and R ² each independently represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group, or a halogen atom, and R ³ and R ⁴ each independently represent a hydrogen atom which may have a substituent alkyl group, an alkoxy group, a halogen atom or -NHCOR ⁷ (R ⁷ is a hydrogen atom, or a substituted represents an alkyl group or an aryl group.) the Represent. R ⁵ and R ⁶ each independently represent an alkyl group, an allyl group or an aryl group which may have a substituent. Hereinafter, the present invention will be described in detail. The indoaniline dye of the present invention represented by the general formula (I) has the following general formula (II)

[0009]

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Wherein Z ¹ , Z ² , R ¹ and R ² have the same meanings as in the above formula (I), and a phenolic compound represented by the following formula (III)

[0011]

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(Wherein, R ^{3 to} R ⁶ have the same meanings as in the general formula (I)) and an aniline compound represented by the formula (I) in an inert solvent in the presence of an oxidizing agent. It can be manufactured by reacting under alkaline conditions of about 0 to 25 ° C. Examples of the solvent used in this reaction include water, water-miscible acetone, tetrahydrofuran, dioxane, dimethylformamide, dimethylsulfoxide, pyridine, alcohols and the like. These solvents are used alone or as a mixture.
Examples of the oxidizing agent used in this reaction include hydrogen peroxide, ammonium persulfate, potassium persulfate, persulfates such as sodium persulfate, ferricyanates, nitrates and the like.

In the general formula (I), the alkyl groups of Z ¹ and Z ² include methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, n-
-Pentyl group, neopentyl group, n-hexyl group, 2-
Examples include a linear or branched alkyl group having 1 to 8 carbon atoms such as an ethylhexyl group, and the substituted alkyl group includes
Alkoxy groups substituted with alkoxy groups such as methoxyethyl group, ethoxyethyl group, butoxyethyl group, benzyl group, alkyl groups substituted with aryl groups such as 2-phenylethyl group, allyl group, β-methallyl group, etc. Examples include an alkyl group substituted with a vinyl group.

Examples of the cycloalkyl group include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the aryl group include a phenyl group, an m-methylphenyl group and a p-methylphenyl group. And a heterocyclic group which may have a substituent includes a 5- or 6-membered heterocyclic group containing a nitrogen atom, an oxygen atom, a sulfur atom, etc. Are 2-thiazolyl group, 4-methyl-2-thiazolyl group, 5-methyl-2-thiazolyl group, 5-methyl-2-isoxazolyl group, 2-thiadiazolyl group, 5-methylthiadiazolyl group, 2-pyridyl And the like.

Examples of the heterocyclic group formed by bonding Z ¹ and Z ² to each other include a 5- or 6-membered heterocyclic group containing a nitrogen atom, an oxygen atom, a sulfur atom, and the like. Examples include a pyrrolidino group, a piperidino group, an N-methylpiperazino group, and a morpholino group. R ¹ , R ² , R
^{When 3} , R ⁴ and R ⁷ represent an alkyl group, specifically, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, n-pentyl,
Examples thereof include a linear or branched alkyl group having 1 to 8 carbon atoms such as a neopentyl group, an n-hexyl group, and a 2-ethylhexyl group. Examples of the substituent of the alkyl group include a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom. When R ¹ , R ² , R ³ , and R ⁴ represent an alkoxy group, specifically, it has 1 to 8 carbon atoms corresponding to the alkyl group
And when it represents a halogen atom, a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom is exemplified.

R^Five, R⁶Is an alkyl group,
Typically, methyl, ethyl, n-propyl, i-propyl
Propyl group, n-butyl group, t-butyl group, n-pentyl
Group, neopentyl group, n-hexyl group, 2-ethylhexyl
C1-C8 linear or branched alkyl such as a sil group
And the substituent is methanesulfonyl
1 carbon atoms such as luamide group and ethanesulfonylamide group
To 8, preferably alkylsulfonyl having 1 to 4 carbon atoms
Amide group; hydroxy group; methoxy group, ethoxy group,
C1-C8 such as a toxic group, preferably C1-C4
Alkoxy groups; halogen atoms such as fluorine and chlorine atoms
Children; aryl groups such as phenyl groups; ants such as phenoxy groups
Oxy group; acetyloxy group, propionyloxy
An acyloxy group such as a benzoyloxy group; methoxy
Alkoxy group such as carbonyl group and ethoxycarbonyl group
Aryloxy such as rubonyl group and phenoxycarbonyl group
A cyclocarbonyl group; a cyano group; a tetrahydrofuryl group, etc.
No. R^Five, R⁶, R ⁷Is an aryl group
Specifically, specifically, a phenyl group, a p-tolyl group, a p-fur
Alkyl such as an olophenyl group and a p-ethoxyphenyl group
Group, an alkoxy group, a halogen atom, etc.
A good phenyl group is mentioned. R^Five, R⁶Allyl group of
As the substituent, an alkyl group such as a methyl group and an ethyl group,
Halogen atoms such as fluorine, chlorine, bromine, etc.
And an aryl group such as a phenyl group.

Among the dyes represented by the general formula (I), preferred are those wherein Z ¹ and Z ² are an alkyl group having 1 to 6 carbon atoms,
Or Z ^1, Z ² is a pyrrolidino group bonded to form one another, piperidino group, and morpholino group, R ^1,
Examples of R ² include a hydrogen atom, an alkyl group having 1 to 4 carbon atoms which may be substituted by a fluorine atom, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom. As R ³ and R ⁴ , a hydrogen atom And an alkyl group having 1 to 4 carbon atoms which may be substituted by a fluorine atom, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, an alkylcarbonylamino group having 2 to 5 carbon atoms, and a formylamino group. ⁵ , R ⁶ is an alkyl group having 1 to 4 carbon atoms which may be substituted by an alkoxy group, an acyloxy group, an alkylsulfonamide group, an alkoxycarbonyl group, a phenoxycarbonyl group, a tetrahydrofuryl group, or a cyano group as a substituent. Is mentioned.

More preferably, R ¹ and R ² are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ³ and R ⁴ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a halogen atom. , R ⁵ , and R ⁶ are alkyl groups which may be substituted with an alkoxy group or a phenyl group.
Specific examples of the dye for thermal transfer used in the present invention,
For example, the following Table 1 can be mentioned, but the present invention is not particularly limited thereby.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

[0023]

[Table 5]

[0024]

[Table 6]

[0025]

[Table 7]

[0026]

[Table 8]

The dye for thermal transfer according to the present invention is usually prepared by dissolving or dispersing the dye in a medium together with a binder resin in the form of fine particles to form an ink, coating the ink on a support and drying the ink. Thus, a heat-sensitive transfer sheet having a color material layer formed on a support is obtained, and used for image formation by a heat-sensitive transfer method. To form a full-color image by the image forming method using the thermal transfer method of the present invention, yellow,
Magenta and cyan dyes are used, and if necessary, four color dyes are added to black. Each dye is 2
More than one kind of the dye of the present invention or a mixture of the dye of the present invention and a known dye may be used. These dyes are arranged on a sheet-shaped or roll-shaped support to form independent regions. For example, yellow area, magenta area,
Cyan areas are arranged in a plane sequence.

As the support, suitable are heat-resistant plastic films such as thin paper such as condenser paper and glassine paper, polyester, polycarbonate, polyamide, polyimide and polyaramid. Their thickness may be in the range of 3 to 50 μm. Among the above base films, a polyethylene terephthalate film is particularly advantageous in consideration of mechanical strength, solvent resistance, economy, and the like. However, in some cases, the polyethylene terephthalate film does not always have sufficient heat resistance and the running performance of the thermal head is insufficient. By providing a layer of a heat-resistant resin containing, for example, the thermal head can be used with improved running properties.

As the binder resin for preparing the above-mentioned ink, in order to prevent thermal fusion with the image receiving layer during thermal transfer recording,
Although those having good heat resistance are used, those having a softening point or heat deformation temperature of 10 ° C. or more are particularly preferable. Specifically, cellulose-based, acrylic acid-based, starch-based water-soluble resin,
Acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, AS resin, polyethersulfone, polyvinylbutyral, polyester, ethylcellulose, acetylcellulose, polyamide, urea resin, and other organic solvents or water-soluble resins can be used. . These resins are preferably used at a ratio of 20 to 500 parts with respect to 100 parts by weight of the dye.

Examples of the solvent for preparing the ink include water, alcohols such as methyl alcohol, isopropyl alcohol and isobutyl alcohol, cell solvents such as methyl cellosolve and ethyl cellosolve, and aromatics such as toluene, xylene and chlorobenzene. , Ethyl acetate, butyl acetate and other esters, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, chlorinated solvents such as methylene chloride, chloroform and trichloroethylene, ethers such as tetrahydrofuran and dioxane, and N, N-dimethylform. Organic solvents such as amides such as amides and N-methylpyrrolidone can be mentioned. These may be used alone or as a mixture.

In the above ink, in addition to the above components,
A release agent can be contained to improve the releasability between the heat-sensitive transfer sheet and the image receiving sheet. Also, it can be formed by applying a release layer on the dye layer, for example,
In order to more effectively achieve the effects of the present invention, such as color transfer characteristics, it is more preferable to include them in the ink. As the release agent, any release agent such as polyethylene wax, a fluorine-based compound, and a silicone-based compound can be used.
Of these, silicone compounds are preferred. Examples of the silicone compound include a carboxy-modified, amino-modified or epoxy-modified silicone oil or resin. For example, X-22-371 manufactured by Shin-Etsu Chemical Co., Ltd.
0, KF-393, KF-105, etc. are effective.

Phenolic, hydroquinone,
Antioxidants such as hindered amines and ultraviolet absorbers such as benzotriazoles, benzophenones and thiazolidones may be added and used. In addition, a known surfactant, particularly preferably a fluorine-based surfactant, may be added for the purpose of improving coating properties, improving releasability, and improving antistatic properties.

The ink can be applied on the base film by using a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, or the like. The thickness is preferably in the range of 0.1 to 5 μm. The image receiving sheet used in combination with the thermal transfer sheet of the present invention has an image receiving layer on a support. The image receiving layer is a binder resin,
The resin is obtained by adding a compound capable of accepting a dye.

Examples of the binder resin used in the image receiving layer include the binder resins used in the above-mentioned ink preparation. Examples of the substance capable of accepting a dye added to the resin include those described in JP-A-62-174754. And high boiling organic solvents. The thickness of the image receiving layer is 0.
It is preferably from 2 to 40 μm, and particularly preferably from 1 to 15 μm.

As the support, synthetic paper (polyolefin, polystyrene, etc.), high quality paper, art paper, coated paper, polyethylene, polypropylene, polyester (polyethylene terephthalate, etc.), polycarbonate, polyamide film, etc. Laminates can be used. In the image receiving sheet, an intermediate layer having a function of a cushion layer, an adhesive layer, and a dye diffusion preventing layer may be further formed between the support and the image receiving layer. The intermediate layer uses a water-soluble binder such as gelatin or an organic soluble binder, and may contain fine particles such as silica, clay, calcium carbonate, titanium oxide, and alumina.

Further, a fluorescent whitening agent may be added to the image receiving layer in order to impart a function of improving whiteness and the like. Examples of the fluorescent brightener include stilbene, coumarin, and benzoxazolyl. Further, in order to improve the releasability between the heat-sensitive transfer sheet and the image receiving sheet, it is preferable to include a release agent on the surface of the image receiving layer of the image receiving sheet or in the image receiving layer.

Also, isocyanates, aldehydes,
A hardener such as an epoxy-based, vinylsulfone-based, or N-methylol-based hardener, the above-described antioxidant, an ultraviolet absorber, and a surfactant can be used. In this case, peelability, slipperiness,
For the purpose of improving the releasability and the like and preventing static charge, it is preferable to use a fluorine-containing surfactant added. In the present invention, the heat-sensitive transfer sheet is superimposed on the image-receiving sheet, and preferably, from the back surface of the heat-sensitive transfer sheet, by applying heat energy according to the image material by a heating means, the dye in the color material layer is transferred to the image-receiving sheet. Image stability, sharpness,
An image having excellent resolution can be transferred. Heating means is not only thermal head, but also laser light, infrared light,
A known device such as a hot pen can be used.

Further, the thermal transfer dye of the present invention can be prepared by a method other than the above-mentioned transfer method using a thermal transfer sheet and an image receiving sheet.
As described in JP-A-5-221155 and JP-A-7-108711, a heat-liquefied dye or a heat-vaporization transfer system in which a dye itself is heat-liquefied and transferred to an image receiving paper can be used. The thermal transfer dye of the present invention is a violet dye, and is particularly useful for producing a black color by mixing with a yellow dye, a magenta dye and a cyan dye.

[0039]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. The dyes used in the following examples are the dyes NO. Are the dyes exemplified above.

Synthesis of Dye a) NO. Synthesis of Dye 1 6.8 g of 1,1-dimethyl-3- (3-hydroxy-4-methylphenyl) urea, 6.2 ml of triethylamine
Was added to 200 ml of tetrahydrofuran and cooled to 5 ° C. In this, 200 ml of acetone, 200 ml of water and 40 ml of 28% ammonia water are added. The solution was kept at 0 to 5 ° C., and with stirring, 2-amino-
7.5 g of 5- (diethylamino) toluene hydrochloride and then 15.9 g of ammonium persulfate are added,
The reaction was carried out at a temperature of 1 hour. After completion of the reaction, water was added, and the precipitated crystals were filtered to obtain the desired NO. A crude crystal of the dye 1 was obtained. The crude crystals were purified by column chromatography on silica gel using chloroform as a running solvent. 5. one dye
3 g were obtained. The maximum absorption of this dye was 558 nm (in acetone), and the melting point was 159 to 160 ° C.

B) NO. Synthesis of Dye No. 3 In place of 7.5 g of 2-amino-5- (diethylamino) toluene hydrochloride in the synthesis example of Dye 1, the same molar number of N, N-diethyl-p-phenylenediamine sulfate was used. The same processing is performed, and the purpose NO. Three dyes were synthesized. The maximum absorption of this dye is
540 nm (in acetone), melting point 153-1
54 ° C.

Example 1 a) Preparation of ink NO. 6 g of the first dye, 10 g of a phenoxy resin (product name: PKHJ, manufactured by UCC), and 90 g of tetrahydrofuran were treated with a paint conditioner for 10 minutes to prepare an ink.

B) Preparation of Thermal Transfer Sheet The above ink was applied to a 6 μm-thick polyethylene terephthalate film whose back surface was heat-resistant and lubricated using a wire bar so that the film thickness after drying was 1.0 μm. After drying, a heat-sensitive transfer sheet was obtained. The heat-resistant lubrication treatment was carried out on a polyethylene terephthalate film using 8 g of a polycarbonate resin and 1 g of a phosphate-based surfactant (trade name:
(Plysurf A-208B: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and a liquid consisting of 91 g of toluene having a film thickness of 0.1 g after drying.
The coating was performed so as to have a thickness of 5 μm and dried.

C) Preparation of Image Receiving Sheet 10 g of polyvinyl chloride resin (a resin of vinyl chloride, vinyl acetate and vinyl alcohol and having a vinyl alcohol content of 5% by weight), silicone resin (product name: L-700)
2. Nippon Unicar Co., Ltd.) 0.6 g, toluene 40 m
l, a liquid consisting of 40 ml of methyl ethyl ketone, was applied to a synthetic paper (product name: YUPO FPG150, manufactured by Oji Yuka Co., Ltd.) with a wire bar so that the film thickness after drying was 5 μm, and the oven was heated at 100 ° C. for 30 minutes. The image was heated and dried to form an image receiving sheet.

D) Thermal Transfer The heat-sensitive transfer sheet and the image receiving sheet obtained as described above are overlapped so that the color material layer and the image receiving layer are in contact with each other, and the thermal head output is 0.12 W from the support side of the thermal transfer sheet. Heat was applied under the conditions of a recording power of / dot, a dot density of 12 dots / mm, a pulse width of head heating of 10 msec, and the dye was thermally transferred to the image receiving layer. As a result, a uniform transferred image was obtained. The recording density on the image receiving layer after the thermal transfer is a densitometer TR-927 manufactured by Macbeth Co., USA.
1.7 (measured using a black SPI filter)
3, and high-density transfer recording was possible. The results are shown in Table 2 below.

Examples 2 to 10 NO. The following table-
A transfer recording and a color transfer test were carried out in the same manner as in Example 1 except that the dye 2 was used. As a result, good results were shown. The results are shown in Table 2 below. Comparative Example 1 Dye No. used in Example 1 In place of 1
In the publication No. -308072, NO. NO. 4 represented by the following structural formula. A heat-sensitive transfer sheet was prepared using 48 dyes in the same manner as in Example 1, and evaluated in the same manner as in Example 1, but the transfer sensitivity was poor. The results are shown in Table 2 below.

[0047]

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[0048]

[Table 9]

[0049]

When the heat-sensitive transfer sheet of the present invention is used, heat transfer recording can be performed uniformly and at a high density, and there is no color transfer to a contact object and the sharpness of an image is good. A thermal transfer image with good performance can be obtained.

Claims (2)

[Claims] 1. A thermal transfer dye represented by the following general formula (I). Embedded image (In the formula, Z ¹ and Z ² each independently represent an alkyl group which may have a substituent, a cycloalkyl group, an aryl group or a heterocyclic group which may have a substituent. ,
R ¹ and R ² each independently represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group, or a halogen atom;
³ and R ⁴ are each independently a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group, a halogen atom, or —NHCOR ⁷ (R ⁷ is a hydrogen atom or a substituent Represents an alkyl group or an aryl group which may be optionally represented). R ⁵ and R ⁶ each independently represent an alkyl group, an allyl group or an aryl group which may have a substituent. ) 2. A heat-sensitive transfer sheet having a color material layer on a support, wherein the color material layer contains the dye for heat transfer according to claim 1.