JPH02147398A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To obtain favorable feeding characteristics without sticking, wrinkling or the like and enhance image quality by incorporating either a combination of a pigment surface-treated with a metallic soap or silicone resin with a resin or a combination of aniline black with a resin into a back layer, in a recording medium comprising a thermal transfer layer on one side of a film base and the back layer on the other side. CONSTITUTION:A base is provided thereon with a back layer on the side opposite to the side of a thermal transfer layer, thereby enhancing matching properties for a thermal head. The back layer comprise a resin as a binder. The resin may be, for example, polyvinyl acetate or polyvinyl butyral. A pigment surface-treated with a metallic soap may be used, which may be obtained by coating the surface of an inorganic pigment such as silica with a metallic soap, and is excellent in heat-releasability at the time of heating and dispersibility. A pigment surface-treated with a silicone resin may be used, which may be obtained by coating the above-mentioned inorganic pigment with a silicone resin, followed by cross-linking by heating, and has excellent lubricity. Aniline black is a black organic pigment, which is obtained by oxidizing an aniline salt, and has excellent heat resistance.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a thermal transfer recording medium that does not cause stick phenomenon or wrinkles, and does not cause thermal head stains. [Prior art] Thermal transfer recording is popular as a plain paper recording method because the equipment used is simple, but as printing speeds have increased in recent years, high energy has been applied to the thermal head, causing the surface of the support film to become The sticking phenomenon of melting and melting on the thermal head became more likely to occur. In order to eliminate this stick phenomenon, several proposals have been made as described below. B. Silicone resin, epoxy resin, etc. on the back surface of the support.
A heat-resistant protective film made of one selected from the group consisting of melamine resin, phenol resin, fluororesin, polyimide resin, and nitrocellulose is provided. (Tokuko Sho 58-13
(Refer to No. 359) Instead of using the resin in (a) and (a), a thermoplastic resin to which a lubricant or a heat release agent is added is used. (Refer to Japanese Patent Application Laid-Open No. 59-225994.) C. By providing a polymer composition containing ultrafine silica particles produced by a vapor phase method on the back surface, the surface is roughened and the contact area with the thermal head is reduced. Improve stability. (Refer to JP-A-80-82385) 2. Silica whose surface has been hydrophobized with a silane coupling agent is bonded with a resin such as PVA to form a back layer. (Refer to JP-A-82-32091) [Problems to be Solved by the Invention] Most of the resins in (a) of the above conventional technology are thermosetting, and PET film is usually used as a support in the heating process. There are problems such as deformation, and
Because the film itself is brittle and has weak adhesion to the support, smooth printing may not be possible. In the case of the first printing method, the molten active agent or thermal release agent oozes out from the back surface during printing, causing head stains and causing problems such as loud stick noise. In the case of C, the hardness of the silica is high, so there is a problem that the thermal head will wear out during long printing, and
Due to the hydrophilicity of silica and the hydrophobicity of release agents such as silicone resins, the film strength decreased, making it difficult to form a stick prevention layer with high mechanical strength. In case 2, problems such as slipperiness with the thermal head and wear of the head are not solved. The present invention attempts to solve the problems in these conventional techniques. [Means for Solving the Problems] The present invention is a thermal transfer recording medium having a thermal transfer layer on one side of a film support and a back layer on the other side, wherein each of the back layers contains the following: This is a thermal transfer recording medium. (1) Contains pigment and resin that have been surface-treated with metal soap. ...Claims (1) (2) Contains a pigment and resin surface-treated with silicone resin. ...Claim (2) (3) Contains aniline black (diamond black) and a resin. ...Claim (3) As the support used in the present invention, films of relatively heat-resistant plastics such as polyester, polycarbonate, triacetyl cellulose, nylon, and polyimide, cellophane, parchment paper, condenser paper, etc. can be used. . The thickness of the support is preferably 1 to 6 μm, but it may be 1 to 20 μm if it is treated to improve the usage conditions and heat transfer efficiency.
It can be used up to a range of thickness. The main components of the thermal transfer layer are a heat-fusible substance and a colorant, and the heat-fusible substance can be any material used in ordinary thermal transfer inks. For example, natural waxes such as spermaceti wax, beeswax, carnauba wax, candilar wax, lanolin, montan wax, montan wax, petroleum waxes such as paraffin wax and microcrystalline wax, ester waxes, synthetic waxes such as low molecular weight polyethylene, various modified waxes, Hydrogenated wax, long chain fatty acids, etc., polyethylene, oxidized polyethylene, polypropylene, terpene resin, ketone resin, ethylene vinyl acetate copolymer, ethylene acrylic copolymer, acrylic resin, polyester resin, coumaron resin, rosin and its derivatives,
Examples include polyamide resin, epoxy resin, polyvinyl chloride, polyurethane resin, polystyrene resin, phenol resin, cellulose resin, and the like. Various inorganic and organic pigments, colored dyes, sublimation dyes, and the like can be used as coloring agents, but carbon black is particularly effective for creating high-density images. This geothermal transfer layer contains oils such as animal and vegetable oils, mineral oils, liquid paraffin, carbonate esters, phthalic acid esters, higher fatty acids, higher alcohols, plasticizers, surfactants, etc., as well as dispersants, penetrants, and adhesives. Additives such as modifiers and fluidity control agents may be added as necessary. The proportion of each material is 20-90% wax, 0-50% adhesive resin, 0-30% additive, and 5-5 colorant by weight.
0% is appropriate. The thickness of the thermal transfer layer is 2 to 20 μm,
More preferably, it is 3 to 10 μm. If it is thinner than 2 μm, image density cannot be ensured, and if it exceeds 20 μm, transferability deteriorates. The thermal transfer layer may be formed by applying a solution prepared by dissolving or dispersing the above materials in water or an organic solvent, or by a hot melt method. A feature of the present invention is that a back layer is provided on the opposite side of the support from the thermal transfer layer to improve the matching property with the thermal head. The back layer of the present invention basically consists of heat-resistant pigments arranged on a support. However, since the pigment alone does not have fixing properties to the support, it is necessary to use a resin as a binder. Any known resin component may be used as the resin of the present invention without particular limitation. Specific examples include polyvinyl acetate, polyvinyl butyral, polyvinyl chloride, polyvinylidene chloride, vinyl acetate-ethylene copolymer, cellulose derivatives such as ethyl cellulose, cellulose acetate, cellulose acetate butyrate, and nitrocellulose, epoxy resins, and phenol. Resin, melamine resin, urea resin, silicone resin, fluororesin, polycarbonate, polyethylene, polyester resin, polyether, polypropylene, polyamide, styrene-maleic acid resin, polyurethane resin,
Examples include polyvinyl alcohol and petroleum resin. The resin component used in the present invention is preferably one having good adhesion to the support, especially one having a glass transition point of 50.
A polymer compound with a temperature of ℃ or higher is preferable. The pigment of the present invention is characterized by the use of a pigment surface-treated with metal soap, a pigment surface-treated with silicone resin, and aniline black (diamond black). Pigments that have been surface-treated with metal soap include inorganic pigments such as calcium carbonate and silica that are covered with a metal soap, that is, a compound of stearic acid and aluminum, zinc, calcium, barium, lithium, lead, etc., and are particularly effective when heated. It has excellent heat releasability and dispersibility. Pigments surface-treated with silicone resin are those in which inorganic pigments such as calcium carbonate and silica are covered with silicone resin and crosslinked by heat, and have particularly excellent slip properties. The amount of silicone resin is preferably 2 to 20% by weight based on the pigment. Aniline black, also called diamond black, is a black organic pigment represented by the following structural formula I, and is produced by oxidizing aniline salt. It has particularly excellent heat resistance among organic pigments, and is black in color, so if the ink layer is black, it makes it difficult to read the printed information from the thermal transfer recording medium after printing, and has the effect of maintaining confidentiality. The ratio of these pigments and resin is preferably in the range of pigment/resin -9713 to 30/70 in ff1la ratio, but it depends on the adhesion of the resin to the support, the specific surface area of the pigment, the apparent specific gravity, oil-absorbing melon, etc. It is a good idea to consider this when determining the ratio. The amount of resin is preferably the minimum amount that will prevent the back layer pigment from falling off during printing, but it is better to consider the dispersibility of the pigment as it is better to disperse the pigment sufficiently to obtain a higher resolution image. . Furthermore, two or more of the above pigments may be used in combination. In addition to pigments and resins, dispersants, lubricants, colorants, etc. can also be added to the back layer.

[Examples] Hereinafter, the present invention will be specifically explained with reference to Examples. Note that the amounts (parts) of each component described in the Examples are parts by weight. Example 1 A dispersed ink having the following composition was coated on one side of a polyester film with a thickness of 4.5 μm using a hot melt coating method to form an ink layer with a thickness of 4 μm. Ink composition Carnauba wax 30 parts Paraffin wax 40 parts Ethylene vinyl acetate copolymer
15 parts carbon black 15 parts Next, a dispersion having the following composition was coated on the ink layer and the other side of the support by a solvent coating method to a thickness of 0.
The back layer was 5 μm thick. Composition of back layer forming liquid Metallic soap Surface treatment Calcium carbonate (Neolite SP manufactured by Takehara Chemical Industry ■) 250 parts Polyester resin (Tg - 88°C) 45 parts Isocyanate
5 parts toluene
400 parts methyl ethyl ketone
400 parts (however, the isocyanate was added after dispersion) A thermal transfer recording medium was thus obtained. Example 2 Instead of the metal soap surface treatment calcium carbonate of the back layer of Example 1, silicone resin surface treatment silica (Mizukashiru P-527 manufactured by Suiko Kagaku Kogyo ■) was used with 10 wt% silicone resin.
A thermal transfer recording medium was obtained in the same manner as in Example 1, except that a thermal transfer recording medium was used. Example 3 Same as Example 1 except that 200 parts of aniline black (Diamond Black 2R-W manufactured by Sumika Color Nakazai) and 5 parts of zinc stearate were used instead of the metal soap surface treatment calcium carbonate in the back layer of Example 1. A thermal transfer recording medium was obtained in the same manner. Comparative Example 1 Thermal transfer recording was carried out in the same manner as in Example 1, except that calcium carbonate without surface treatment (Takehara Chemical Industry Co., Ltd. Sunlight #1000) was used instead of the metal soap surface-treated calcium carbonate in the back layer of Example 1. Got the medium. Comparative Example 2 A thermal transfer recording medium was obtained in the same manner as in Example 1 except that metal soap surface treatment of the back layer in Example 1 was not added. Comparative Example 3 A thermal transfer recording medium was obtained in the same manner as in Example 1 except that 50 parts of carbon black (Printex P-25 manufactured by Degussa) was used instead of the metal soap surface treatment calcium carbonate in the back layer of Example 1. . Commercially available thermal transfer printer (applied energy 0
．． 6 mJ/dot) using the thermal transfer recording media prepared in the above examples and comparative examples.
c). The printing condition was evaluated as follows. Stick 20 - Printing was possible without fusing to the thermal head. Δ-- Instantly fused, but separated immediately. Stick music large. Horizontal white lines appeared on the image. × - Printing stopped due to fusion. Damage to the support. Wrinkles: After printing, the ink sheet and image were visually evaluated. ○ - No wrinkles Δ - Both images did not have any effect, but wrinkles did occur. x - White streaks having the same shape as wrinkles appeared in the image. Head stain: The thermal head was observed with a magnifying glass after printing 20 consecutive A4 size originals. 〇 - No stain Δ - White or black substance attached. x - Fragments of the ink sheet were attached. Effects of the Invention As explained above, when the thermal transfer recording medium of the present invention is used in a thermal transfer recording method, good conveyance without stickiness, wrinkles, etc. can be obtained, and image quality can be improved.

Claims (3)

[Claims] (1) A thermal transfer recording medium having a thermal transfer layer on one side of a film support and a back layer on the other side, wherein the back layer contains a pigment and a resin surface-treated with metal soap. Medium. (2) A thermal transfer recording medium having a thermal transfer layer on one side of a film support and a back layer on the other side, wherein the back layer contains a pigment and a resin surface-treated with a silicone resin. Medium. (3) A thermal transfer recording medium having a thermal transfer layer on one side of a film support and a back layer on the other side, wherein the back layer contains aniline black (diamond black) and a resin. .