JPH0825342B2 - Magenta color thermal transfer sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a transfer sheet used for sublimation thermal transfer recording.

(Prior Art) Conventionally, a technology for color recording a facsimile printer, a copying machine, a television image or the like has been demanded, and a color recording technology by electrophotography, ink jet, thermal transfer or the like has been studied.

The thermal transfer recording method is considered to be advantageous as compared with other methods because the apparatus is easy to maintain and operate and the apparatus and consumables are inexpensive.

The heat-sensitive transfer method is a melting 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 recording is performed 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. The sublimation method is applied to the thermal head. Since the sublimation transfer amount of the dye can be controlled by changing the energy, gradation recording becomes easy, which is considered to be particularly advantageous for full-color recording.

However, in the sublimation type thermal transfer recording, transfer recording can be performed with low energy, and further, the obtained recorded matter does not have good storage stability, and those satisfying these characteristics are required.

Both of the dyes represented by the general formulas [I] and [II] have a vivid magenta color, and a heat-sensitive transfer sheet using them can be used to obtain a vivid magenta color recorded matter. However, the heat-sensitive transfer sheet using only the imidazole azo dye represented by the general formula [I] has very good storage stability of the obtained recorded matter but has low sensitivity, and in order to obtain sufficient recording density, , Requires a lot of energy when recording. On the other hand, the thermal transfer sheet using only the tricyanovinyl dye represented by the general formula [II] has very high sensitivity and can obtain sufficient recording density with low energy, but the obtained recorded matter can be stored. Stability is particularly low in light resistance.

(Problems to be Solved by the Invention) The present inventors have conducted studies on a heat-sensitive transfer sheet capable of obtaining a magenta recording material having good sensitivity and good storage stability. It has been found that the object can be achieved by using a heat-sensitive transfer sheet having a color material layer containing a mixture of dyes represented by [I] and [II].

That is, it is an object of the present invention to provide a magenta color heat-sensitive transfer sheet which can be transferred and recorded with low energy because of its good sensitivity, and which can provide a recorded matter with good storage stability.

(Means for Solving the Problems) The present invention provides a heat-sensitive transfer sheet comprising a base film and a color material layer containing a mixture of dyes represented by the following general formulas [I] and [II]. It is a summary.

(In the formula [I], X represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a formylamino group, a lower alkylcarbonylamino group, a lower alkylsulfonylamino group or a lower alkoxycarbonylamino group, and Y represents a hydrogen atom,
It represents a lower alkyl group, a lower alkoxy group or a halogen atom, and R ¹ , R ² and R ³ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an allyl group or a substituted or unsubstituted aryl group. [II] In the formula, Z represents a hydrogen atom or a lower alkyl group, R ⁴ and R ⁵ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an allyl group or a substituted or unsubstituted aryl group. , R ⁴ may be further bonded to the carbon atom adjacent to the bonding carbon atom of the nitrogen atom bonded to the benzene ring to form a hetero 6-membered ring).

 The details of the present invention will be described below.

Examples of the lower alkyl group and lower alkoxy group of the substituents X, Y and Z in the general formulas [I] and [II] include C _{1 to} C ₄ linear or branched alkyl groups and alkoxy groups. The lower alkylcarbonylamino group, lower alkylsulfonylamino group, lower alkoxycarbonylamino group, lower alkyl group and lower alkoxy group for X are C _{1 to} C ₄ linear or branched alkyl groups and alkoxy groups. Is mentioned. Further, examples of the halogen atom of Y include a fluorine atom and a chlorine atom.

Examples of the unsubstituted alkyl group represented by R ^{1 to} R ^{5 in} the general formulas [I] and [II] include C _{1 to} C ₁₂ linear or branched alkyl groups. Examples of the substituted alkyl group include , Alkoxy groups, alkoxyalkoxy groups, aryloxy groups, allyloxy groups, aralkyloxy groups, aryl groups, cyano groups, hydroxy groups, halogen atoms, furyl groups, tetrahydrofuryl groups, alkoxycarbonyl groups,
Examples thereof include a C _{1 to} C ₁₂ linear or branched alkyl group substituted with an allyloxycarbonyl group or an acyloxy group.

Examples of the alkyl group substituted with an alkoxy group include a 2-methoxyethyl group, a 2-ethoxyethyl group, a 2- (n) propoxyethyl group, a 2- (iso) propoxyethyl group,
2- (n) butoxyethyl group, 2- (iso) butoxyethyl group, 2- (sec) butoxyethyl group, 2- (n) pentyloxyethyl group, 2- (n) hexyloxyethyl group, 2- ( n) octyloxyethyl group, 2- (2 '
-Ethylhexyloxy) ethyl group, 1-methyl-2-
Methoxyethyl group, 1-methyl-2-ethoxyethyl group, 1-methyl-2- (n) propoxyethyl group, 1-
Methyl-2- (iso) propoxyethyl group, 1-methyl-2- (n) butoxyethyl group, 1-methyl-2- (is
o) Butoxyethyl group, 1-methyl-2- (n) hexyloxyethyl group, 1-methyl-2- (2'-ethylhexyloxy) ethyl group, 3-methoxybutyl group, 3-
Examples thereof include an ethoxybutyl group, a 1-ethyl-2-methoxyethyl group, and a 1-ethyl-2-ethoxyethyl group, and a C ₃ -C ₈ β-alkoxyethyl group is particularly preferable.

As the alkyl group substituted with an aralkyloxy group, a 2-benzyloxyethyl group, a 1-methyl-2-benzyloxyethyl group, a 1-ethyl-2-benzyloxyethyl group, a 2- (β-phenylethyl) oxyethyl group And so on.

The alkyl group substituted with an allyloxy group is 2-
Examples thereof include an allyloxyethyl group, a 1-methyl-2-allyloxyethyl group, a 1-ethyl-2-allyloxyethyl group and the like.

2 as an alkyl group substituted with an aryloxy group
-Phenoxyethyl group, 1-methyl-2-phenoxyethyl group, 1-ethyl-2-phenoxyethyl group and the like.

Examples of the alkyl group substituted with an alkoxyalkoxy group include a 2- (2′-methoxyethoxy) ethyl group and a 2- (2′-methoxyethoxy) ethyl group.
(2'-Ethoxyethoxy) ethyl group, 2- {2'-
(N) butoxyethoxy) ethyl group, 2- {2'-
(N) Hexyloxyethoxy} ethyl group, 2- {2 '
-(N) octyloxyethoxy} ethyl group, 2-
{2 '-(iso) butoxyethoxy} ethyl group, 1-methyl-2- (2'-methoxyethoxy) ethyl group, 1-
Methyl -2 {2 '- (n) butoxyethoxy} ethyl group, 3- (2'-methoxyethoxy) but a butyl group, especially, a C ₅ ~C ₁₀ β- (β'- alkoxyethoxy) The ethyl group is preferred.

Examples of the alkyl group substituted with a cyano group include 2-cyanoethyl group and cyanomethyl group, and examples of the alkyl group substituted with a hydroxy group include 2-hydroxyethyl group and 3.
-Hydroxy (n) propyl group, 4-hydroxy (n)
Butyl group, 1-methyl-2-hydroxyethyl group, 1-
An ethyl-2-hydroxyethyl group or the like is a 2-chloroethyl group as an alkyl group substituted with a halogen atom,
2-Bromoethyl group, 2,2,2-trifluoroethyl group, etc., furfuryl group as an alkyl group substituted with a furyl group, and tetrahydrofurfuryl group as an aryl group as an alkyl group substituted with a tetrahydrofuryl group Examples of the alkyl group substituted with include a benzyl group, a p-chlorobenzyl group, a 2-phenylethyl group and the like.

Examples of the alkyl group substituted with an alkoxycarbonyl group or an allyloxycarbonyl group include 2-methoxycarbonylethyl group, 2-ethoxycarbonylethyl group, 2-
(Iso) butoxycarbonylethyl group, 2- (n) hexyloxycarbonyl group, 1-methyl-2-methoxycarbonylethyl group, 1-methyl-2- (n) butoxycarbonylethyl group, 2-allyloxycarbonylethyl group , 1-methyl-2-allyloxycarbonylethyl group, methoxycarbonylmethyl group, ethoxycarbonylmethyl group, (iso) butoxycarbonylmethyl group,
(N) Hexyloxycarbonylmethyl group, 2-ethylhexyloxycarbonylmethyl group and the like.

The alkyl group substituted with an acyloxy group is 2-
Acetoxyethyl group, 2-propionyloxyethyl group, 2-benzoyloxyethyl group, 3-acetoxy (n) propyl group, 4-acetoxy (n) butyl group, 1
-Methyl-2-acetoxyethyl group, 1-ethyl-2-
An acetoxyethyl group etc. are mentioned.

Examples of the cycloalkyl group represented by R ^{1 to} R ⁵ in formulas [I] and [II] include a cyclopentyl group and a cyclohexyl group.

Examples of the substituted or unsubstituted aryl group of R ^{1 to} R ^{5 in} the general formulas [I] and [II] include a substituted or unsubstituted phenyl group, and the substituent is a C _{1 to} C ₄ lower alkyl group. Group, a C ₁ -C ₄ lower alkoxy group, a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom, and a trifluoromethyl group.

In the general formula [II], examples of the compound in which R ⁴ is combined with a benzene ring to form a hetero 6-membered ring include those represented by the following general formula [III].

(In the formula, R ⁶ , R ⁷ , and R ⁸ represent a hydrogen atom or a methyl group,
Z and R ⁵ have the same meanings as in the general formula [II].

Among the dyes represented by the general formula [II], preferred dyes are those represented by the above general formula [III] in which Z is a hydrogen atom or a methyl group, R ⁵ is an alkyl group having 1 to 8 carbon atoms, and alkoxyalkyl having 3 to 8 carbon atoms. A group, a benzyl group or a β-phenylethyl group, and R ⁶ , R ⁷ and R ⁸ each represent a hydrogen atom or a methyl group.

In the general formula [II], Z represents a hydrogen atom or a methyl group, R ⁴ and R ⁵ represent an alkyl group having 1 to 8 carbon atoms, an alkoxyalkyl group having 3 to 8 carbon atoms, a benzyl group or a β-phenylethyl group. The dyes represented are likewise preferred.

On the other hand, in the dye represented by the general formula [I], preferable substituents are as follows: X is a formylamino group, an acetylamino group or another alkylcarbonylamino group having 2 to 5 carbon atoms, a hydrogen atom, a methyl group or a methoxy group, Y Is a hydrogen atom, R ¹ and R ² are allyl groups, alkyl groups having 1 to 8 carbon atoms, alkoxyalkyl groups having 3 to 8 carbon atoms, benzyl groups, β-phenethyl groups or hydroxyl groups, halogen atoms or cyano groups. A substituted alkyl group having 2 to 8 carbon atoms, R ₃ is an alkyl group having 1 to 8 carbon atoms, an allyl group, a cyanomethyl group, a cyanoethyl group, or an alkoxycarbonylmethyl group having an alkoxy group having 1 to 8 carbon atoms, or It is an alkoxycarbonylethyl group.

In the present invention, a preferable heat-sensitive transfer sheet can be obtained by using the dye represented by the general formula [I] and the dye represented by the general formula [II] in combination. A more preferable one can be obtained by selecting and using together.

The weight ratio of the dyes represented by the general formulas [I] and [II] is appropriately in the range of 1: 5 to 5: 1.
A range of ~ 5: 1 is suitable.

When the coloring material layer is formed on the heat-sensitive transfer sheet of the present invention using the above dye, the method is not particularly limited, and usually, the dye is dissolved or finely dispersed in the medium together with the binder. An ink is prepared, and the ink is applied onto a base film and dried to form a color material layer on the base film.

As a binder for preparing the ink, cellulose-based,
Acrylic acid, starch-based water-soluble resin, acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, polyether sulfone, polyvinyl butyral, ethyl cellulose, acetyl cellulose,
Examples thereof include resins soluble in organic solvents such as polyester and AS resin.

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 a base film for applying the ink for producing the transfer sheet, condenser paper, thin paper such as glassine paper, polyester, polycarbonate, polyamide,
A film of a plastic having good heat resistance such as polyimide or polyaramid is suitable, and the thickness thereof can be in the range of 3 to 50 μm. Of the above base films, the polyester terephthalate film is mechanical. It is particularly advantageous in consideration of 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, so that heat resistance that includes a surfactant, heat-resistant particles with high lubricity, etc. on the opposite surface of the color material layer. By providing a layer of a functional resin, a thermal head having improved running properties can be used.

The ink can be applied to the base film by using a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, etc., and the thickness of the ink coating layer is in the range of 0.1 to 5 μm after drying. It should be applied so that it becomes (Yuji Harasaki, Maki Shoten
Published in 1979 "Coating method").

Further, the heat-sensitive transfer sheet of the present invention can use not only a thermal head but also infrared rays, laser light, etc. as a heating means.

Alternatively, an electrically conductive film designed to generate heat by applying electricity to the base film itself can be used as an electrically conductive thermal transfer sheet.

(Example) 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 Apply a mixture of the above composition with paint conditioner 10
The ink was prepared by processing for 1 minute.

b) Preparation of transfer sheet A polyethylene terephthalate film (6 μm) whose back surface was heat-resistant and slip-treated with a wire bar was used.
m) and then dried (dry film thickness: about 1 μm) to obtain a transfer sheet. In addition, the polyethylene terephthalate film is subjected to the heat-resistant lubricity treatment by applying the following formula A liquid consisting of 8 parts by weight of a polycarbonate resin having a repeating structural unit represented by: 1 part by weight of a phosphate ester-based surfactant (trade name: PRYSURF A208B: Dai-ichi Kogyo Seiyaku Co., Ltd.) and 91 parts by weight of toluene is applied. And dried (dry film thickness of about 0.5 μm).

c) Preparation of image receptor 10 parts of saturated polyester resin (product name: TP-220, manufactured by Nippon Gosei Co., Ltd.), amino-modified silicone (product name: KF3)
93, Shin-Etsu Chemical Co., Ltd. product) 0.5 part, methyl ethyl ketone 15 parts, xylene 15 parts liquid on synthetic paper (Product name: YUPO FPG150, Oji Yuka Co., Ltd. product) with a wire bar and dry (dry film thickness) An image receptor was prepared by further heat-treating in an oven at 100 ° C. for 30 minutes.

d) Transfer recording The ink-coated surface of the transfer sheet was superposed on the recording medium and recording was performed under the following conditions using a thermal head, and the recording characteristics shown in FIG. 1 were exhibited.

Recording conditions Linear density for main scanning and sub scanning: 6 dots / mm Recording power: 0.4 W / dot Head heating time: 0 to 10 ms Color density is densitometer TR manufactured by Macbeth, USA
It was measured using a -927 type.

e) Light fastness test The light fastness test of the record (with a color density of about 1.0) obtained in d) above was carried out using a carbon arc fade meter (manufactured by Suga Test Instruments Co., Ltd.) (black panel temperature 63).
± 2 ° C) and the degree of discoloration and fading after irradiation for 80 hours {ΔE (L ^*
a ^* b ^* )} is shown in Table 1.

Comparative Example 1 In the same manner as in Example 1 except that 6 g of the dye (A) used in Example 1 was used in the ink preparation, ink preparation, transfer sheet preparation, image receptor preparation and transfer recording were carried out. As a result, the recording characteristics shown in FIG. 1 were exhibited. The results of the light resistance test are shown in Table 1.

Comparative Example 2 In the same manner as in Example 1 except that 6 g of the dye (B) used in Example 1 was used in the ink preparation, ink preparation, transfer sheet preparation, image receptor preparation and transfer recording were carried out. As a result, the recording characteristics shown in FIG. 1 were exhibited. The results of the light resistance test are shown in Table 1.

Table 1 Light resistance test results Example 2 In the same manner as in Example 1 except that the following dyes (C) and (D) were used instead of the dyes (A) and (B) used in Example 1 in the preparation of the ink. Ink preparation, transfer sheet preparation, image receptor preparation, transfer recording and light fastness test were conducted and the results shown in Table 2 were obtained.

Comparative Example 3 In the ink preparation, only 6 g of the dye (C) used in Example 2 was used, and otherwise the same method as in Example 2 was carried out to prepare the ink, transfer sheet, image receptor, and transfer. Recording and light fastness tests were performed and the results shown in Table 2 were obtained.

Comparative Example 4 In the ink preparation, 6 g of the dye (D) used in Example 2 alone was used, and otherwise the same method as in Example 2 was carried out to prepare the ink, transfer sheet, image receptor, and transfer material. Recording and light fastness tests were performed and the results shown in Table 2 were obtained.

Example 3 Ink was prepared in the same manner as in Example 1 except that the following dyes (E) and (F) were used instead of the dyes (A) and (B) used in Example 1 in the preparation of the ink. Was prepared, a transfer sheet was prepared, an image receptor was prepared, transfer recording and a light resistance test were conducted, and the results shown in Table 2 were obtained.

Comparative Example 5 In the preparation of the ink, 6 g of the dye (E) used in Example 3 alone was used, and otherwise the same method as in Example 3 was carried out to prepare the ink, transfer sheet, image receptor and transfer recording. Then, a light resistance test was conducted and the results shown in Table 2 were obtained.

Comparative Example 6 In the preparation of the ink, 6 g of the dye (F) used in Example 3 alone was used, and otherwise the same procedure as in Example 3 was carried out to prepare ink, transfer sheet, and image receptor. Transfer recording and a light resistance test were performed, and the results shown in Table 2 were obtained.

Example 4 In the same manner as in Example 1 except that the following dyes (G) and (H) were used instead of the dyes (A) and (B) used in Example 1 in the preparation of the ink. , Ink preparation, transfer sheet preparation, image receptor preparation, transfer recording and light resistance test were carried out, and the results shown in Table 2 were obtained.

Comparative Example 7 In the preparation of an ink, 6 g of the dye (G) used in Example 4 alone was used, and otherwise the same procedure as in Example 4 was carried out to prepare an ink, a transfer sheet, an image receptor, and a transfer. Recording and light fastness tests were conducted and the results shown in Table 2 were obtained.

Comparative Example 8 In the ink preparation, only 6 g of the dye (H) used in Example 4 was used, and otherwise the same method as in Example was carried out to prepare ink, transfer sheet, image receptor, and transfer recording. Then, the light resistance test was performed and the results shown in Table 2 were obtained.

(Operation and Effect of the Invention) When the heat-sensitive transfer sheet of the present invention is used, it is possible to obtain a high density magenta color recorded product with low energy,
Further, the storage stability of the obtained recorded matter is very good.

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.

[Brief description of drawings]

FIG. 1 shows recording characteristics when thermal transfer recording is performed using the transfer sheets prepared in Example 1 of the present invention and Comparative Examples 1 and 2. In the figure, the vertical axis represents color density, and the horizontal axis represents head application time (milliseconds).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukichi Murata 1000 Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryo Kasei Co., Ltd. (72) Inventor Takao Hirota 1000, Kamoshida-cho, Midori-ku, Yokohama (56) Reference JP-A-59-78896 (JP, A) JP-A-60-110494 (JP, A) JP-A-60-260391 (JP, A) JP-A-1- 136787 (JP, A)

Claims (2)

[Claims] 1. A magenta color heat-sensitive transfer sheet having a color material layer containing a mixture of dyes represented by the following general formulas [I] and [II] on a base film. (In the formula [I], X represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a formylamino group, a lower alkylcarbonylamino group, a lower alkylsulfonylamino group or a lower alkoxycarbonylamino group, and Y represents a hydrogen atom,
It represents a lower alkyl group, a lower alkoxy group or a halogen atom, and R ¹ , R ² and R ³ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an allyl group or a substituted or unsubstituted aryl group. [II] In the formula, Z represents a hydrogen atom or a lower alkyl group, R ⁴ and R ⁵ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an allyl group or a substituted or unsubstituted aryl group. , R ⁴ may be further bonded to the carbon atom adjacent to the bonding carbon atom of the nitrogen atom bonded to the benzene ring to form a hetero 6-membered ring). 2. The magenta heat-sensitive transfer sheet according to claim 1, wherein the weight ratio of the dyes represented by the general formulas [I] and [II] is 1: 5 to 5: 1. .