JPH085257B2 - Dye for thermal transfer recording and thermal transfer sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dye for heat-sensitive transfer recording used in sublimation-type heat-sensitive transfer recording, and a heat-sensitive transfer sheet using the dye.

(Prior Art) Conventionally, there has been a demand for a technology for color recording a facsimile printer, a copying machine, a television image or the like, 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 thermal transfer system includes a base film and a base film having a heat-meltable ink layer formed thereon. The transfer sheet 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, but the sublimation method is a thermal head. Since the sublimation transfer amount of the dye can be controlled by changing the applied energy, gradation recording becomes easy, which is considered to be particularly advantageous for full-color recording.

In sublimation thermal transfer recording, the sublimable dye used in the transfer sheet is very important because it greatly affects the transfer recording speed, the image quality of the recorded matter, storage stability, etc. It is necessary to fill.

 Easily sublimate under the operating conditions of the thermal recording head.

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

 It should have a favorable hue for color reproduction.

 Large molecular extinction coefficient.

 Stable against heat, light, moisture, chemicals, etc.

 Easy synthesis.

 Excellent ink suitability.

 There are no safety and health problems.

A dye satisfying all the above conditions has not been found so far, and a yellow dye, in particular, has various drawbacks and no satisfactory dye has been found yet.

(Problems to be Solved by the Invention) An object of the present invention is to provide a yellow dye for heat-sensitive transfer recording which satisfies all the above conditions, and a heat-sensitive transfer sheet using the dye.

(Means for Solving Problems) The present invention provides the following general color [I]. (In the formula, X represents a hydrogen atom or a halogen atom, and R ¹ and
I ² 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) The gist of the present invention is a heat-sensitive transfer sheet characterized by having a quinophthalone type heat-sensitive transfer recording dye and a coloring material layer containing the dye.

The quinophthalone-based dye for thermal transfer recording represented by the above general formula [I] of the present invention will be described.

As the halogen atom of X in the above formula [I],
Examples thereof include chlorine atom and bromine atom.

The alkyl group of R ¹ and R ² , a methyl group, an ethyl group, a linear or branched propyl group, a butyl group,
Examples thereof include C _{1 to} C ₈ alkyl groups such as a pentyl group, a hexyl group, a heptyl group, and an octyl group.

Examples of the alkoxyalkyl group include 2-methoxyethyl group, 2-ethoxyethyl group, 2- (n) propoxyethyl group, 2- (iso) propoxyethyl group, 2- (n) butoxyethyl group, 2- (iso) butoxy group. Ethyl group, 2-
(Sec) butoxyethyl group, 3-methoxypropyl group,
3-ethoxypropyl group, 3- (n) propoxypropyl group, 3- (iso) propoxypropyl group, 3- (n)
Examples thereof include C _{2 to} C ₈ alkoxyalkyl groups such as butoxypropyl group, 3- (iso) butoxypropyl group, and 3- (sec) butoxypropyl group.

Examples of the aralkyl group include C _{7 to} C ₈ aralkyl groups such as a benzyl group and a 2-phenylethyl group, and examples of the cycloalkyl group include a cyclopentyl group and a cyclohexyl group.

Examples of the aryl group include a substituted or unsubstituted aryl group, and the substituted aryl group includes a lower alkyl group such as a methyl group, an ethyl group, and a butyl group, a lower alkoxy group such as a methoxy group, an ethoxy group, and a butoxy group, Examples thereof include a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom, and a phenyl group having a substituent such as a trifluoromethyl group.

Examples of the hydroxyalkyl group include hydroxy lower alkyl groups such as 2-hydroxyethyl group and 3-hydroxypropyl group.

Incidentally, these dyes may be mixed and used, if necessary.

These dyes are described, for example, in U.S. Patent No. 3,023,213.
It can be produced by a known method as described in Japanese Patent No. 2,210,168 or the like.

When the above dye is applied to the heat-sensitive transfer sheet of the present invention, the method is not particularly limited, and usually, the dye is dissolved or dispersed in a medium in a medium together with a binder to prepare an ink, The color material layer is formed on the base film by applying the ink on the base film and drying.

As a binder for preparing the ink, cellulose-based,
Acrylic acid-based, starch-based and other water-soluble resins, acrylic resins, methacrylic resins, polystyrene, polycarbonate, polysulfones, polyether sulfones, polyvinyl butyral, ethyl cellulose, acetyl cellulose, and other organic solvents or water-soluble resins. it can.

As a medium for ink preparation, in addition to water, alcohols such as methyl alcohol, isopropyl alcohol and isobutyl alcohol, methyl cellosolve, cellosolves such as ethyl cellosolve, aromatics such as toluene, xylene and chlorobenzene, ethyl acetate, Esters such as butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, ketones such as cyclohexanone, methylene chloride, chloroform, chlorinated solvents such as trichloroethylene, ethers such as tetrahydrofuran and dioxane, N, N-dimethylformamide, N- Organic solvents such as methylpyrrolidone may be mentioned.

In addition to the above components, organic or 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 in the ink. can do.

The base film to which the ink for producing the transfer sheet is applied includes condenser paper, thin paper such as glassine paper, polyester, polycarbonate, polyamide,
Plastic films 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, polyethylene terephthalate film is particularly advantageous in consideration of mechanical strength, solvent resistance, economy and the like. However, in some cases, polyethylene terephthalate film does not always have sufficient heat resistance, and the thermal head has insufficient running property. By providing a layer of a heat-resistant resin containing the thermal head, it is possible to use a thermal head having improved runnability.

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 ink application layer is 0.1 to 5 μm after drying. It should be applied so that it becomes (Yuji Harasaki, Maki Shoten 19
Issued in 1979, "Coating method").

(Operation and Effect of the Invention) Since the dye for thermal transfer recording of the present invention has a vivid yellow color, it is suitable for obtaining a full-color recording with good color reproducibility by combining with an appropriate magenta color and cyan color. In addition, since sublimation is easy and the molecular extinction coefficient is large, it is possible to obtain high-speed recording with high color density without imposing a heavy burden on the thermal head. Furthermore, since it is stable against heat, light, moisture, chemicals, etc., it does not decompose thermally during transfer recording, and the resulting record is excellent in storability and particularly excellent in light resistance. Further, since the dye has good solubility in an organic solvent and dispersibility in water, it is easy to prepare a high-concentration ink that is uniformly dissolved or dispersed. It is possible to obtain a heat-sensitive transfer sheet which is uniformly applied in high concentration. Therefore, by using such a heat-sensitive transfer sheet, it is possible to obtain a recording with good uniformity and color density.

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

(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) Ink preparation The mixture having the above composition was treated with a paint conditioner for 10 minutes to prepare an ink.

b) Preparation of transfer sheet 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 has the following heat-resistant lubricity treatment. 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: Plysurf A-208B: a product of Dai-ichi Kogyo Seiyaku Co., Ltd.), and 91 parts by weight of toluene. Was applied and dried (dry film thickness: about 0.5 μm).

c) Preparation of image receptor 10 parts of saturated polyester resin (product name: TP-220, product of 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 overlaid on the recording medium and a thermal head was used to record under the following conditions.
Records of 40 uniform color densities could be obtained.

Recording conditions Cotton density in main scan and sub-scan: 8 dots / mm Recording power: 0.25 W / dot Head heating time: 10 msec Color density is Densitometer TR manufactured by Macbeth Co., USA
It was measured using a -927 type.

The light resistance test of the obtained record was conducted using a carbon arc fade meter (manufactured by Suga Test Instruments Co., Ltd.) (black panel temperature 63 ± 2 ° C.), but almost no discoloration or fading occurred after irradiation for 40 hours. Further, the transfer sheet and the record were stable against heat and humidity, and had excellent storage stability in the dark.

Example 2 The dyes shown in Table 1 were used in place of the dyes used in Example 1, and ink was prepared, a transfer sheet was prepared, and transfer recording was carried out in the same manner as in Example 1, and the results are shown in Table 1. A clear yellow color record having the indicated color density could be obtained.

The results of the light fastness test of the obtained recording and the darkness storage stability test of the transfer sheet and the recording were good.

Claims (2)

[Claims] 1. The following general formula [I] (In the formula, X represents a hydrogen atom or a halogen atom, and R ¹ and
R ² 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). The indicated quinophthalone dye for thermal transfer recording. 2. A base film having the following general formula [I] (In the formula, X represents a hydrogen atom or a halogen atom, and R ¹ and
R ² 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). A heat-sensitive transfer sheet having a coloring material layer containing a quinophthalone dye shown.