JPS60184881A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer recording medium capable of printing with low energy and transferring high-density coloring matter images multiple times with little reduction in density, by providing an intermediate layer comprising a highly heat-conductive fine powder and a resin between a base and a heat-fusible coloring material layer. CONSTITUTION:The intermediate layer comprising a highly heat-conductive fine powder and a resin is provided between the base and the heat-fusible coloring material layer. The resin to be mixed with the fine powder to form the intermediate layer is preferably a resin which shows high adhesion to the base and the coloring material layer and has a melting or softening point of 40-150 deg.C. Particularly, a polyvinyl butyral resin, an epoxy resin or the like generally produces favorable results. The fine powder may be a powder of a metal such as aluminum and copper, an oxide such as tin oxide, aluminum oxide and magnesium oxide or a nitride such as titanium nitride, and the particle diameter thereof is preferably not larger than 3mum, more preferably, not larger than 1mum. In mixing the resin with the power, the proportion of the powder is preferably 10- 90vol%, more preferably, 20-60vol%.

Description

[Detailed description of the invention] [Technical field] The present invention relates to thermal transfer recording media that can be used multiple times.

More specifically, the present invention relates to a thermal transfer recording medium that exhibits a small decrease in density with the number of uses, can be printed with low energy, and provides printing quality with high density and excellent resolution.

[Prior Art] An example of a thermal transfer recording medium intended for multiple use is the invention described in Japanese Patent Application Laid-open No. 54-68253. This invention is a technique in which a microporous layer is formed using a resin and the pores are impregnated with heat-melting ink, but the density of the dye transfer image is low, and it is difficult to obtain a high density dye transfer image. This requires high energy, and even if a high-density dye transfer image is obtained by applying high energy, the edges of the printed image lack sharpness. Japanese Unexamined Patent Publication 1973-
105579 also discloses a technique similar to the above, but it has the same drawbacks.

In addition to the above, heat-sensitive transfer recording media that can be used many times using various techniques are being considered. For example, JP-A-57-1
As shown in Japanese Patent No. 85195, a method of grafting vinyl chloride onto carbon black, No. 57-3
No. 6698, No. 57-138984, No. 58-116
193 and No. 58-155995, there are known ones in which an intermediate layer for adhesion is provided between the base material and the ink layer (heat-melting color material layer). These prevent all of the colorant from being transferred at once when heated with a thermal head, and although each of them is effective to some extent, it is still insufficient.

[Object of the Invention] An object of the present invention is to provide a thermal transfer recording medium that is capable of low-energy printing, has little density loss with respect to the number of uses, and can obtain high-density dye transfer images many times. It is to provide.

Other objects of the invention will become apparent from the following description of the specification.

[Summary of the Invention] As a result of intensive research, the present inventor has discovered that in a thermal transfer recording medium in which a heat-fusible coloring material layer is laminated on a support, a It has been discovered that the above object can be achieved by interposing an intermediate layer containing a highly thermally conductive fine powder and a resin, leading to the present invention.

[Structure of the invention] The present invention will be described in further detail below.

In the thermal transfer recording medium of the present invention, an intermediate layer consisting of a resin layer in which highly thermally conductive fine powder is dispersed is interposed between the support and the heat-melting coloring material layer.

Preferably, resin binder is used to form an intermediate layer by kneading with the highly thermally conductive fine powder used in the thermal transfer recording medium of the present invention.
Especially polyvinyl butyral resin or epoxy resin 1U
etc. generally give good results. The highly thermally conductive fine powder has a higher thermal conductivity than the above-mentioned resin (for example, thermal conductivity of 8.OX+o-' to 25.oxlo-' cal/
It only needs to have a high melting point (see 11 degrees Celsius) and a high melting point, and many monometallic materials such as aluminum and copper are possible, as well as oxides such as tin oxide, aluminum oxide, and magnesium oxide, and nitrides such as titanium nitride. 9 The fine powder with high thermal conductivity of the present invention that can be used has a particle size of 31 Lm.
The distance is preferably 171 m or less. The mixing ratio of the resin and the fine powder is preferably such that the volume fraction of the fine powder is 10 to 90%, more preferably 20 to 60%. This is because if the volume fraction of the fine powder is smaller than this, the effect of thermal conductivity cannot be achieved, whereas if it is larger than this, the adhesive strength with the support and the colorant layer will be reduced, and the multi-printing performance will be reduced.

The highly thermally conductive fine powder may be dispersed and contained in at least the intermediate layer, and may also be contained in the support and/or the colorant layer. The particle size of the highly conductive fine powder used in the present invention may be larger than the thickness of the intermediate layer; in this case, a portion of the fine powder will protrude into the colorant layer, which will impede the effects of the present invention. Never.

The heat-melting coloring material layer in the present invention mainly contains a low melting point substance,
It consists of a coloring agent and a softening agent, and as a low melting point substance,
Melting point (measured by Yanagimoto MPJ-2 model 1et) F40
~120℃ 1-11 bodies are half 1. ', is a one-dimensional substance, and examples of the substrate include 1, such as carnauba wax, wood wax,
Plant waxes such as auriculie wax and esparto wax, animal waxes such as beeswax, insect wax, shellac wax and whale wax,
paraffin wax, microcrystalline wax,
In addition to waxes such as petroleum waxes such as ester wax and oxidized wax, and mineral waxes such as montan wax, osichelite, and ceresin, higher fatty acids such as harmitic acid, stearic acid, margarine, and behenic acid; palmitinamine-J
and higher alcohols such as stearyl alcohol alcohol and eicosanol; higher fatty acid esters such as cetyl palmitate, myricyl palmitate, cetyl stearate, and myricyl stearate;
Amides such as acetamide, propionic acid amide, palmitic acid amide, stearic acid amide, amide wax; rosin derivatives such as ester gum, rosin maleic acid resin, rosin phenolic resin, hydrogenated rosin; phenolic resin, terpene resin, cyclopentadiene Polymer compounds with a softening point of 50-120'C such as resins and aromatic resins; higher amines such as ste-7lylamine, behenylamine, and palmitinamine; polyethylene oxides such as polyethylene glycol 4000 and polyethylene glycol 6000, etc. These may be used alone or in combination; among these, higher amides such as palmitic acid amide, stearic acid amide, oleic acid amide, and amido-wax are particularly preferred. Also, JP-A-54-6
The "thermally compatible solid component that is solid at room temperature" described in Japanese Patent Publication No. 8253 and the "vehicle" described in Japanese Patent Application Laid-Open No. 55-105579 may also be used.

The colorant used in the present invention may be appropriately selected from conventionally known pigments, including direct dyes, acid dyes, basic dyes, disperse dyes, and oil-soluble dyes (including metal-containing oil-soluble dyes). You can choose from among these. The dye used in the color material layer of the present invention may be transferred (transferred) together with a heat-melting substance.
In addition to the above, pigments may be used as long as they are functional pigments. In addition, specifically, the following can be mentioned. That is, as the yellow pigment, Kayalon Polyester Light Yellow 5G-5 (Nikki Kayaku), Oil Yellow o-S-
7 (White J2), Eisensviron GRH Special (Hodogaya), Sumiplast Ie o-FG (OE Tomo), Eisenspiron Yellow GRH (Hodogaya), etc. are preferably used. As a red pigment, diaceteritonephus 7),
DoR (Mitsubishi Kasei), Dianix Brilliant Red BS-E (Mitsubishi Kasei), Sumiplus Trend FB (
Suitably used are Sumiplast Tread HFG (Jinja), Kayalon Polyester Pink RCL-E (Nippon Kayaku), Isenspiron Red GEH Special (Hodogaya), and the like. As blue pigments, Diaceritone Fast Brilliant Blue R (Mitsubishi Kasei), Dianic Sprue EB-E (Mitsubishi Kasei), Kayalon Polyester Blue B-3F Conch (Nippon Kayaku), Sumiplast Blue 31 (Senizen), A Sumiplast Blue G (resident) rod is preferably used. In addition, as yellow pigments, Hansa Yellow 3G, Taldrazine Lake, etc. are used, as red pigments, brilliant carmine FB-Pure (deuterochrome), brilliant carmine 6B (deuterochrome), alizarin lake, etc. are used, and blue pigments are used. Examples include Cerulean Blue, Sumikablin Tocyanine Blue GN-0 (
phthalocyanine blue, etc., and carbon black, oil blank, etc. are used as the black pigment.

Examples of the softener used in the present invention include low softening point polymers selected from ethylene-ethyl acrylate copolymers, ethylene-vinyl acetate copolymers, and the like.

Note that the support used in the thermal transfer recording medium of the present invention is preferably a support that has heat-resistant strength, high dimensional stability, and high surface smoothness. For example, the material is tai-toshi paper,
Paper such as capacitor paper, laminated paper, coated paper, or polyethylene, polyethylene terephthalate 1,
Resin films such as polystyrene, polypropylene, and polyimide, paper-resin film composites, and metal sheet caps such as aluminum foil are all suitably used. The thickness of one literary figure is usually about 60 μm or less at −1 to obtain good thermal conductivity, and preferably 2 to 20 ALm at 41F. Furthermore, in the thermal transfer recording medium of the present invention, the structure on the back side of the support may be arbitrary, and a backing layer such as a stinking prevention layer may be provided.

In the heat-sensitive transfer recording medium of the present invention, techniques suitable for applying the intermediate layer to a support such as a polymer film and techniques suitable for applying the heat-melting coloring material layer to L of the intermediate layer include:
Said JP-A-54-68253 and JP-A-55-105579
These techniques are described in various publications and are well known in the art, and these techniques can also be used in the present invention. For example, the intermediate layer (and the heat-melting coloring material layer) is formed by true-melt coating of the composition, or by bullbent coating with a coating solution prepared by dissolving or dispersing the composition in an appropriate solvent. It is a layer. The intermediate layer of the present invention (
As a coating method for the heat-melting coloring material layer), any known technique can be employed, such as a reverse roll coater method, an extrusion coater method, a gravure coater method, and a wire coater method.

The heat-melting coloring material layer of the present invention may have a thickness of 20#L+w or less, more preferably 11-15P. Further, the intermediate layer of the present invention may have a weight of 3 gva or less, more preferably 1 gm or less.

[Effects of the Invention] According to the present invention, in a heat-sensitive transfer recording medium in which a heat-melting coloring material layer is laminated on a support, a highly thermally conductive fine powder or a heat-melting coloring material layer is disposed between the support and the heat-melting coloring material layer. Since the structure includes an intervening intermediate layer containing Yohi resin, the above-mentioned object of the present invention can be achieved.

Example 1 Examples will be given below, but the embodiments of the present invention are not limited thereto. In addition, "department" used below means "
"claw hook part" is shown.

Example 1 An intermediate layer was obtained by applying an ethylene-ethyl acrylate solution having the following composition to a 5.3 gm thick polyethylene terephthalate film using a wire parser so that the dry film thickness was 0.13 gm. Ta.

Copper powder (particle size 3JLI11 or less) 10 parts Toluene 10
After drying, the following colorant layer coating solution was coated using a wire bar so that the dry film thickness was 12 mm, and then heated in a dryer at 100°C for 20 minutes to obtain the thermal transfer recording of the present invention. A medium sample ■ was obtained.

Carbon black 10 parts Microcrystalline wax 40 parts (Micro UH
120 parts of toluene (manufactured by BARECO) This thermal transfer recording medium sample ■ was printed using a thermal printer (prototype machine equipped with a thin-film line thermal head with a heating element density of 8 dots/am) so that the applied power per heating element was 0. Recording (printing) was performed on plain paper by applying energy of .6 W for an application time of 1 millisecond. This was repeated 1 to 5 times. Note that commercially available high-quality paper (80 g/m') was used as the plain paper.

As a result, printing with sufficient density was obtained even after more than 5 printings, as shown by ■ in FIG. Furthermore, the print quality was also good.

Comparative Example 1 An intermediate layer was coated on a 5.3 gm thick polyethylene terephthalate film in the same manner as in Example 1.

No high thermal conductivity fine powder was added to this intermediate layer. After drying, a colorant layer having the same composition as in Example 1 was dried for 11 yen and the thickness was 12 ml.
After applying the coating so that the temperature was 100 mm, it was heated in a dryer at 100'O for 20 minutes to obtain a comparative thermal transfer recording medium sample "Shino". Using this thermal transfer recording medium sample 1, Example 1 was prepared. Printing was carried out using a thermal printer in the same manner as in Figure 1. As a result, the density (D wax) was low and the print quality was poor, as shown by ■ in FIG.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the number of printing times and the density of the dye transfer image for the thermal transfer recording medium sample (X) of the present invention and the comparative thermal transfer recording medium sample (2). Patent applicant: Konishiroku Photo Industry Co., Ltd. Agent: Nobuaki Sakaguchi (and one other person)

Claims (1)

[Claims] In a heat-sensitive transfer recording medium in which a heat-melting coloring material layer is laminated on a support, an intermediate layer containing a highly thermally conductive fine powder and a resin is interposed between the support and the heat-melting coloring material layer. A thermal transfer recording medium characterized by: