JPS62149493A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer recording medium capable of reproducing colors with higher fidelity and higher color density and having higher preservation stability, by incorporating a specified coloring matter into a coloring material layer, in a thermal transfer recording medium which comprises at least one heat-fusible coloring material layer on a base. CONSTITUTION:A coloring matter of general formula (I), wherein each of R1 and R2, which may be the same or different, is an alkyl, is incorporated into a coloring material layer, in a thermal transfer recording medium which comprises at least one heat-fusible coloring material layer on a base. The coloring material layer comprises 5-20pts.wt. of a coloring material, 50-90pts.wt. of a heat-fusible substance and 0-30pts.wt. of a resin per 100pts.wt. of the total amount of the layer. Recorded images obtained by the thermal transfer recording medium comprising the coloring matter have a clear magenta color, so that when the recording medium is combined with thermal transfer recording media comprising a yellow coloring matter and a cyan coloring matter, respectively, a full-color image can be obtained with favorable color reproduction properties.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermal transfer recording medium, and more specifically to a thermal transfer recording medium that has excellent color reproducibility and improved storage stability of recorded color images. Regarding.

[Conventional technology and problems]

Currently, a fusion type thermal transfer recording method has been proposed as a means of obtaining color hard copies from CRT color displays, color 7-inch cameras, magnetic cameras, and the like.

In this method, a thermal transfer recording medium coated with a thermofusible ink containing a pigment as a coloring agent and a wax as a thermofusible substance is heated with a yf' (thermal head) to heat the thermal recording medium. This is a method of melting and transferring the color to a wave recording medium to obtain a color record.

In this method, pigments for printing inks or paints have conventionally been mainly used as dyes, but the recorded images obtained from the A transfer recording medium using these pigments have the following drawbacks. It was

A desirable hue cannot be obtained in terms of color reproduction.

■Insufficient color density cannot be obtained.

■Storage stability such as light resistance and weather resistance (heat resistance, moisture resistance, etc.) is not sufficient.

Attempts have also been made to improve the uni-deficiency by using specific dyes. For example, 1, certain cyanoazole dyes (Japanese Unexamined Patent Publication No. 60-30394), specific tricyano dyes (Patent No. 60-31563)
A thermal transfer recording medium containing the following has been proposed.

However, even with these 'F' steps, the recorded color images obtained from thermal transfer recording media are still not in a satisfactory state. There is a demand for quantitative determination of thermal transfer recording media having the following properties.

[Purpose of the invention]

An object of the present invention is to provide a legal transfer recording medium that embodies the following performances (I) to (3).

(I) The recorded image has a favorable hue in terms of color reproduction.

(2) The recorded image has a color density equal to that of light.

(3) Storage stability such as light resistance and weather resistance of the recorded image is sufficient.

[Structure of the invention]

The above-mentioned object of the present invention is to provide a heat-sensitive transfer recording medium comprising at least one (4) heat-fusible colorant/ffi coated on a support, in which the colorant layer is represented by the following general formula (I). This is achieved by incorporating a dye.

General Formula (I) In the formula, Ro and R2 represent each /J alkyl group, and may be the same or different.

The present invention will be explained in detail below.

The dye represented by the general formula (I) used in the present invention is a quinacridone dye. In the general formula (I), the alkyl group represented by R and R2 has 1 to 3 carbon atoms.
0. Preferred are straight or branched alkyl groups of 1 to 20, such as methyl, ethyl, isopropyl, butyl, octyl, 2-ethylhexyl, dodecyl, octadecyl, eicosyl, etc. can. This alkyl group can have a substituent, and examples of the substituent include a halogen atom, a hydroxy group, an alkoxy group, an aryloxy group, an alkylsulfonyl group, and an acylamide group.

Specific examples of the quinacridone dye represented by the general formula (+) of the present invention are shown below, but the present invention is not limited thereto.

(a) (i) (e) (e) These dyes can be prepared by introducing an alkyl group into unsubstituted quinacridone according to a known method.

can be obtained easily.

The coloring material (4) in the present invention contains a heat-fusible substance.

Specific examples of heat-melting substances include paraffin wax,
paraffin-based 7-nox such as Polyethylene 7-nox, microwanx, and polyethylene 7-nox; natural waxes such as beeswax, carnauba wax, and wood wax; ester-based waxes such as Hoechst-wax; stearic acid, palmitic acid, behenic acid, and myristic acid. acids, higher fatty acids such as 1,20-eicosanedioic acid, higher alcohols such as ste-7lyl alcohol and palmityl alcohol, higher amides such as stearamide, oleo-7mide, palmitylamide, butyl stearate, ethyl palmitate, Examples include esters such as myristyl stearate. Two or more of these heat f8@l substances may be used in combination.

It is preferable that the color material layer of the present invention contains a resin. The (M IJff) used in the present invention preferably has a softening point (measured by the ring and ball method) of 40 to 200°C, and can be either a woody polymer or a hydrophobic polymer. Examples include gelatin, gelatin: JJ derivatives, cellulose conductors, proteins such as casein, natural products and natural product derivatives such as polysaccharides such as starch, water-soluble polyvinyl compounds such as polyvinyl alcohol, polyvinyl vicritone, and acrylamide polymers. Examples of hydrophobic polymers include synthetic water-soluble polymers, as well as vinyl and polyurethane polymer latexes. Examples of hydrophobic polymers include US Pat.
Examples of synthetic polymers described in Patent No. 3,143,386, Patent No. 3,062,674, Patent No. 3,220,844, Patent No. 3,287,289, and Patent No. 3,411,911 may be cited as examples. can. Preferred polymers include 1 polyvinyl butyral, polyvinyl formal, polyethylene, polypropylene, polyamide, ethyl cellulose, cellulose acetate, polystyrene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, Examples include vinyl chloride-acetic acid and nyl-maleic acid terpolymers, acrylic resins such as polymethyl methacrylate, polyisobutylene, rosin derivatives such as esters, etc. In the present invention, from among these resins, They may be used alone or in combination of two or more.

Although the composition ratio of the coloring material layer of the present invention is not limited, 5 to 5 parts of the coloring material is added to 100 parts (parts by weight, the same shall apply hereinafter) of the total amount of the coloring material layer.
20 parts, heat-melting substance 50-90 parts, resin 0-3
It is 0 copies.

In the present invention, a so-called dispersant may be used to disperse the coloring agent or to keep the dispersion state stable.

Specific examples include nrubitan fatty acid ester, unsaturated fatty acid alkylolamide, alkylimidacillin, polyacrylic acid partial fatty acid ester, alkylbenzenesulfonic acid calcium salt, and the like.

The color material layer of the present invention may contain various additives in addition to the above components. For example, powder or whole particles of a metal with good thermal conductivity such as aluminum, copper, or zinc can be added as a thermally conductive substance. Such a thermally conductive substance promotes the heat conduction effect of melting, softening, or sublimating the coloring material layer by heat. In addition, as a flexible peg,
Vegetable oils such as castor oil, linseed oil, olive oil, animal oils such as whale oil and mineral oils may suitably be used.

The support used in the present invention may be any known support, but it is desirable that the support has heat-resistant strength, dimensional stability, and surface smoothness. Heat-resistant strength requires strength and dimensional stability to maintain the toughness of the support without becoming compacted or plasticized by the heating temperature of a heat source such as a thermal hend, and surface smoothness requires the ability to maintain the toughness of the support without becoming compacted or plasticized by the heating temperature of a heat source such as a thermal hend. It is desired that the coloring material (a) M containing an evasive substance has sufficient smoothness to exhibit a good transfer rate. The smoothness should be 100 sec or more in the smoothness test (JIS P 8119) using a Beck test strip (JIS P 8119). If the smoothness is 300 sec or more, images with better transfer rate and reproducibility can be obtained. For example, paper such as plain paper, condenser paper, laminated paper, coated paper, resin films such as polyethylene, polyethylene terephthalate, polyester, polystyrene, polypropylene, polyimide, paper-resin film composites, aluminum foil, etc. Metal sheets and the like are preferably used.

The thickness of the support is usually about 60 to obtain good thermal conductivity.
It is preferably 0 μm or less, particularly 2 to 20 μIn.

Furthermore, in the thermal transfer recording medium of the present invention, the structure of the back side of the support is arbitrary.

The thermal transfer recording medium of the present invention has at least one coloring material layer obtained by the present invention, and has layers constituting the layer such as a subbing layer, an intermediate layer, or an overcoat layer. good. That is, for example, examples of the undercoat layer include silicone resin, melamine resin, polyvinyl acetal resin, polyethylene, polyvinyl chloride, polyvinylidene chloride, fluororesin, etc. The undercoat layer is applied before the coloring material layer is applied. It can be done by

Techniques suitable for applying the coloring material layer to a support such as a polymer film in the thermal transfer recording medium of the present invention are known in the art, and these known techniques can also be applied to the present invention. For example, configuration 1 containing heat-melting coloring material/I'W
(The composition may be hot-melt coated or
Alternatively, Wr is formed by solvent coating a coating solution obtained by dissolving or dispersing the composition in an appropriate solvent.

As a coating method for the constituent layers including the heat-resistant colorant layer of the present invention, any technique such as a reverse roll coater method, an extrusion coater method, a gravure coater method, a wire bar coating method, etc. can be employed. The heat-melting coloring material layer of the present invention has a thickness of 20 μm or less,
More preferably, it is 1 to 8μ+6.

The thermal transfer recording medium of the present invention may have other constituent layers such as an undercoat layer (for example, a layer for improving film adhesion), an intermediate Rη, and an overcoat layer.

A method for thermal transfer recording using the thermal transfer recording medium of the present invention will be described below.

The component layer surface of the thermal transfer recording medium of the present invention and a recording sheet such as plain paper are stacked, and a thermal recording device using a thermal head, a thermal vent, or a racer is used to print from the thermal transfer recording medium side according to the image information. Alternatively, when energy is applied from the recording sheet side, relatively low energy is applied to the heat-fusible colorant layer, so that the colorant and the like are transferred to the recording sheet together with the heat-fusible substance.

The recorded image obtained from the thermal transfer recording medium containing the dye of the present invention is a clear magenta color.

A full-color image with good color reproducibility can be obtained by combining it with a heat-sensitive transfer recording medium containing yellow or cyan dye.

For example, a full-color image thermally transferred using a thermal transfer recording medium containing a cyan dye and a yellow dye in addition to the magenta dye of the present invention had very good color reproducibility.

Further, other magenta dyes can be used in combination with the dye of the present invention.

〔Example〕

Examples will be described below, but the embodiments of the present invention are not limited thereto. Note that the "section" used below refers to the rTJLm section.

Example 1 The following colorant layer compositions (a), (I]) and (c) were applied onto a polyethylene terephthalate film having a thickness of 6 μlfi so that the dry film thickness was 3 μto to produce a thermal transfer recording of the present invention. Media samples (Δ), (D) and (C) were obtained.

Coloring material layer composition (a) Exemplary compound (a) 10 parts Ester wax (ILoecl+st Wax F, manufactured by Hoechst)
50 parts Microcrystalline wax (ULTRAFLEX, manufactured by Toyo Hetrolite Co., Ltd.) 3
0 parts ethylene-ethyl acrylate copolymer (I) UC
-6070, manufactured by Nippon Unicar Co., Ltd.) 5 parts Petroleum resin (Alcon P-100, manufactured by Arayo Kagaku Co., Ltd.) 5 parts Coloring material layer composition (b) Exemplary compound (A) Except for changing to Exemplary compound (A), Same as coloring material layer composition (a).

Coloring material layer composition (c) Same as coloring material N composition (a) except that exemplified compound (a) was changed to exemplified compound vJ(ri).

Comparative Example 1 In Example 1, the exemplary compound (a) in the colorant layer composition (a) was replaced with a magenta color pigment (C, 1,1585) having the following structure.
A comparative thermal transfer recording medium sample (D) was obtained in the same manner as in Example 1 except that the ratio was changed to 0:1).

Comparative Example 2 In Comparative Example 1, magenta pigment (C01,1585
0: 1) All the following vIA pigments (C, 1, 12
355) 1. : All except for change i, r, and knee (A comparative thermal transfer recording medium sample (E) was obtained in the same manner.

The thermal transfer recording medium samples obtained in the above Examples and Comparative Examples were printed using a thermal printer (heating element density: 8 clots).
A magenta color recorded image was obtained by printing on plain paper with an applied energy of 0.5 mJ/dot using a prototype machine equipped with a thin film type line thermal head of /ma+. The results of measuring the optical reflection density of the solid printed area using λa+ax are
Shown in the table.

Next, the recorded image was transferred to an eooow xenon lamp.
After 8 hours of exposure, the illuminance on the recorded image was 6000 lux),
The light resistance of the recorded image was evaluated based on the residual rate shown below. This result is also shown in the f51 table.

Do: Optical reflection density before exposure DI: Optical reflection density after exposure ＼ Less than 1, Table 1 Furthermore, when the color reproducibility of these samples was visually evaluated, it was found that compared to the comparison sample [/' Samples A and B of the present invention for E
and C both had extremely good reproducibility.

Claims (1)

[Scope of Claims] A heat-sensitive transfer recording medium comprising at least one heat-melting coloring material layer coated on a support, wherein the coloring material layer contains a dye represented by the following general formula (I). A thermal transfer recording medium characterized by: General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R_1 and R_2 each represent an alkyl group,
It can be the same or different. ]