JPH0825341B2 - Yellow 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 more advantageous than the ground method because the apparatus can be easily maintained and operated and the apparatus and consumables are inexpensive.

The thermal transfer method includes a melting method in which a 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 recording is performed on a recording medium, and a base film. 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. It is possible to control the dye sublimation transfer amount by changing the applied energy, which facilitates gradation recording,
It is considered particularly advantageous for full-color recording.

However, in sublimation thermal transfer recording, transfer recording can be performed with low energy, and there is no one with good maintenance stability of the obtained recorded matter. Therefore, those satisfying these requirements are required.

The present inventors have found that the dyes represented by the general formulas [I] and [II] are both bright yellow, and a heat-sensitive transfer sheet using each of them produces a bright yellow recorded matter. I found that earlier.

However, the heat-sensitive transfer sheet using only the quinophthalone-based dye represented by the general formula [I] has very good storage stability but low sensitivity, and in order to obtain a sufficient recording density, It requires a lot of energy when recording.

On the other hand, the heat-sensitive transfer sheet using only the styryl dye represented by the general formula [II] has very high sensitivity and can obtain a sufficient recording density with low energy, but the storage stability of the obtained recorded matter. In particular, the light resistance is low.

[Problems to be Solved by the Invention]

The present inventors have conducted studies on a heat-sensitive transfer sheet capable of obtaining a yellow recording material having good sensitivity and good storage stability, and as a result, the heat-sensitive transfer sheet is represented by the above general formulas [I] and [II]. It has been found that the object can be achieved by using a heat-sensitive transfer sheet having a coloring material layer containing a mixture of dyes.

It is an object of the present invention to provide a yellow-type heat-sensitive transfer sheet which can be transferred and recorded with low energy because of its good sensitivity and which can give a recorded matter having good storage stability.

(Means for Solving the Problems) The present invention is characterized by having a coloring material layer containing a dye represented by the following general formula [I] and a dye represented by the general formula [II] on a base film. The main point is a thermal transfer sheet.

(In the formula [I], X represents a hydrogen atom or a halogen atom, and Y represents a hydrogen atom, COOR ³ or CONR ⁴ R ⁵ .
R ³ , 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.

[II] In the formula, Z represents a hydrogen atom, a chlorine atom or a lower alkyl group, and R ¹ and R ² represent a substituted or unsubstituted alkyl group, a cycloalkyl group, an allyl group or a substituted or unsubstituted aryl group. . ) The contents of the present invention will be described in detail below.

The dye used in the present invention is represented by the general formulas [I] and [II], and the halogen atom of X in the general formula [I] includes a chlorine atom and a bromine atom. General formula (II)
Examples of the lower alkyl group for Z include C ₁ -C ₄ linear and branched alkyl groups.

Examples of the unsubstituted alkyl group of R ^{1 to} R ^{5 in} the general formulas [I] and [II] include C _{1 to} C ₁₂ linear or branched alkyl groups, and the substituted alkyl group is , 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) octylethoxy] ethyl group, 2- [2'-
(Iso) butoxyethoxy] ethyl group, 1-methyl-2
-(2'-methoxyethoxy) ethyl group, 1-methyl-
2- [2 '-(n) butoxyethoxy] ethyl group, 3-
Examples thereof include (2′-methoxyethoxy) butyl group, but especially C _{5 to} 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 cyanoethyl 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., a furfuryl group as an alkyl group substituted with a furyl group, a tetrahydrofurfuryl group as an alkyl group substituted with a tetrahydrofuryl group, an aryl group Examples of the alkyl group substituted with a group include a benzyl group, a p-chlorobenzyl group and a 2-phenylethyl group.

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

Further, among the dyes represented by the general formula [I], the dyes represented by the following structural formulas [III] and [IV] are preferable.

(In the formula, X ¹ is a hydrogen atom, a halogen atom, R ⁶ is an alkyl group, an alkoxyalkyl group, an aralkyloxyalkyl group, an allyloxyalkyl group, an aryloxyalkyl group, a tetrahydrofurfuryl group, a furfuryl group, a cycloalkyl group, Represents an allyl group or an aralkyl group) (In the formula, X ² represents a hydrogen atom or a halogen atom, and R ⁷ and
R ⁸ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, a cycloalkyl group, an allyl group, an aryl group which may have a substituent, an aralkyl group, a furfuryl group, a tetrahydrofurfuryl group or a hydroxyalkyl group) In the dye represented by the formula [III], as a further preferable substituent, X ¹ is a hydrogen atom or a bromine atom,
R ⁶ is particularly preferably an alkyl group having 4 to 12 carbon atoms.

Further, as a more preferable substituent in the dye represented by the general formula [IV], X ² is a hydrogen atom or a bromine atom,
As R ⁷ and R ⁸ , an alkyl group having 1 to 4 carbon atoms is particularly preferable.

Further, as a more preferable substituent in the dye represented by the general formula [II], Z is a hydrogen atom or a methyl group, R ¹ and R ² are alkyl groups having 1 to 8 carbon atoms, and 3 are carbon atoms. To 8 are alkoxyalkyl groups, benzyl groups, β-phenethyl groups, β-cyanoethyl groups, β
It is preferably a -chloroethyl group, a β-hydroxyethyl group or an allyl group.

In the present invention, a preferable heat-sensitive transfer sheet can be obtained by using the dyes represented by the general formulas [I] and [II] in combination, and as described above, the preferable dyes among the general formulas It is more preferable to select and use.

The mixing ratio of the dyes represented by the general formulas [I] and [II] is preferably 1: 5 to 5: 1 by weight, but particularly 1:
A range of 2-5: 1 is suitable.

In that case, it is more preferable to mix two or more of the dyes of [I] because the solubility is improved.

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 ink preparation, in addition to water, alcohols such as methyl alcohol, isopropyl alcohol and isobutyl alcohol, cellosolves such as methyl cellosolve and acyl 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, cyclohexanone, chlorinated solvents such as methylene chloride, chloroform and trichloroethylene, ethers such as tetrahydrofuran and dioxane, N, N-dimethylformamide, N Mention may be made of organic solvents such as methyl hirolidone.

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,
Films of plastics having good heat resistance such as polyimide and polyaramid are suitable, and the thickness thereof can be in the range of 3 to 50 μm.

Of the above base films, the 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, 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.

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 amount of the ink is 0.1 to 5 μm after drying.
It should be applied so that it is within the range of (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 dye 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 The mixture having the above composition was treated with a paint conditioner for 10 minutes to prepare an ink.

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 phosphoric acid ester-based surfactant (trade name: PRYSURF A-208B: Dai-ichi Kogyo Seiyaku Co., Ltd.), and 91 parts by weight of toluene. Was 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) An image receptor was prepared by 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 using a thermal head under the following conditions. As a result, the recording characteristics shown in FIG. 1 were exhibited.

Recording conditions Linear density for main scanning and sub scanning: 6 dots / mm Recording power: 0.21 W / dot Head heating time: 0 to 13 ms Color density is Densitometer TR manufactured by Macbeth, USA
It was measured using a -927 type.

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

Example 2 In the same manner as in Example 1, except that 3 g of the dye (B) and 3 g of the dye (C) used in Example 1 were used in the preparation of the ink of Example 1, an ink was prepared and a transfer sheet was prepared. As a result of the above-mentioned production, image-receiving body production and transfer recording, the recording characteristics shown in FIG. 1 were exhibited. The results of the light resistance test are 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.

Comparative Example 3 In the same manner as in Example 1 except that 6 g of the dye (C) 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.

Example 3 Dye (A) used in Example 1 in the preparation of the ink,
Instead of (B) and (C), the following dyes (D),
By the same method as in Example 1 except that (E) and (F) were used, 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. Obtained.

Comparative Example 4 In the same manner as in Example 3, except that 6 g of the dye (D) used in Example 3 was used in the preparation of the ink, the ink was prepared, the transfer sheet was prepared, the image receptor was prepared, and the transfer was performed. Recording and light fastness tests were performed 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 procedure as in Example 3 was carried out to prepare the ink, transfer sheet, and image receptor. Transfer recording and a light resistance test were performed, 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.

(Operation and Effect of the Invention) When the heat-sensitive transfer sheet of the present invention is used, a high density yellow recorded matter can be obtained with low energy, and the obtained recorded matter has very good storage stability. .

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 heat-sensitive recording is performed using the transfer sheets produced in Examples 1 and 2 and Comparative Examples 1, 2 and 3. 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 60-110494 (JP, A) JP 60-260391 (JP, A) JP 61-148095 (JP, A) JP 1- 136787 (JP, A)

Claims (2)

[Claims] 1. A yellow-type heat-sensitive transfer sheet having a color material layer containing a dye represented by the following general formula [I] and a dye represented by the general formula [II] on a base film. (In the formula [I], X represents a hydrogen atom or a halogen atom, and Y represents a hydrogen atom, COOR ³ or CONR ⁴ R ⁵ .
R ³ , 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. [II] In the formula, Z represents a hydrogen atom, a chlorine atom or a lower alkyl group, and R ¹ and R ² represent a substituted or unsubstituted alkyl group, a cycloalkyl group, an allyl group or a substituted or unsubstituted aryl group. . ) 2. The yellow heat-sensitive transfer sheet according to claim 1, wherein the weight ratio of the dyes represented by the general formulas [I] and [II] is in the range of 1: 5 to 5: 1.