JPH0441080B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a thermal transfer medium applied to printers, plotters, etc. Prior Art The thermal recording method has been widely put into practical use due to its ease of handling, low cost, and storage stability.Once the thermal transfer medium is used, the ink composition applied on the base material is transferred to the recording sheet. There was a drawback that it moved completely upwards. Therefore, recording media equipped with a recording layer that can be thermally copied many times have been developed, but either no adhesive layer is used between the base material and the recording layer, or resins such as acrylic, which are well-known as adhesives, are used. The one using 1
The recording layer may peel off during the second transfer, making it impossible to perform the second and subsequent transfers. Purpose The present invention aims to prevent peeling of the recording layer and to stably perform thermal transfer many times, which is the original purpose. Structure The present invention provides a thermal transfer medium in which an adhesive layer is provided on a base material and a heat-melting ink layer is provided on the adhesive layer.
The gist of the present invention is a thermal transfer medium characterized in that the adhesive layer is made of one or more of nitrocellulose, acetylcellulose, cellulose acetate butyrate, and cellulose propionate. In other words, as a result of repeated research on many resin-based adhesives, we discovered that nitrocellulose, acetylcellulose, cellulose acetate butyrate, and cellulose propionate are optimal as adhesives for thermal transfer media for multiple transfers. Therefore, the present invention has been made. The above resins may be used alone or in combination, and the thickness of the adhesive layer is preferably in the range of 0.05 to 8 μm. These resins have strong adhesive strength, so the recording layer does not peel off even after multiple transfers, and since the adhesive layer can be formed thin, thermal transfer can be carried out efficiently without significantly reducing thermal conductivity. can. The heat-melting ink layer may be one containing a heat-melting solid component and a coloring agent component in a microporous resin layer, or one containing a solvent dye, a low-melting point compound, and a fine powder such as carbon black. In the former example, resins include polyvinyl chloride, polyvinyl acetate, polyvinyl fluoride, polyvinyl butyral, polyvinylidene chloride, polyvinyl alcohol, vinyl chloride/vinylidene acetate copolymer, vinyl chloride/vinylidene chloride copolymer, etc. Vinyl resins, acrylic resins such as polyacrylic esters and polymethacrylic esters, cellulose resins such as ethyl cellulose and cellulose acetate, other polystyrene, polyethylene, polyethylene/vinyl acetate copolymers, polyamides, ABS resins, Further examples include gelatin, gum arabic, and the like. In addition, examples of heat-melting solid components or low melting point compounds include paraffin wax, microcrystalline wax, ceresin wax, carnauba wax, montan wax,
Polyethylene wax, oxidized polyethylene wax, castor wax, hardened beef tallow oil, carbo wax, wood wax, lanolin, stearic acid monoglyceride, sorbitan monostearate, sorbitol hexastearate, pentaerythritol stearate, polyoxyethylene monostearate, These include stearyl alcohol, other synthetic oxidized waxes, synthetic and natural ester waxes, and hydrogenated waxes. Examples of the coloring agent include carbon black, lake red, alkali blue, and crystal violet lactone. Examples of solvent dyes include anthraquinone dyes and azo dyes. As the base material, thin paper such as capacitor paper or glassine paper, or polymer film such as polyamide film, polyimide film, polyester film, or polycarbonate film can be used. Next, examples and comparative examples will be described. Example 1 Acetyl cellulose (trade name L-70, manufactured by Daicel Chemical Industries, Ltd.) was dissolved in acetone and coated on a support made of 15 μm capacitor paper so that the thickness after drying was 1 μm. Example 2 Cellulose acetate butyrate (reagent manufactured by Kanto Kagaku Co., Ltd.) was dissolved in acetone and coated on a support made of 15 μm capacitor paper so that the thickness after drying was 1 μm. Comparative Example 1 Only a support made of capacitor paper with a thickness of 15 μm was used. Comparative example 2 Acrylic resin (product name: Dianal LR-
396, manufactured by Mitsubishi Rayon Co., Ltd.) was dissolved in toluene,
It was coated on a support made of 15 μm capacitor paper so that the thickness after drying was 1 μm. Separately, an ink liquid was prepared as follows. Parts by weight of ink liquid formulation Vinyl chloride/vinyl acetate copolymer 10 Carnauba wax 7 Castor wax 11 Carbon black 4 Ethyl acetate 51 Toluene 17 First, carbon black, carnauba wax,
Mix castor wax at 85℃ and knead thoroughly using a three-roll mill to create ink ingredients. Meanwhile, put the vinyl chloride/vinyl acetate copolymer, ethyl acetate, and toluene into a ball mill, and stir at 50°C for 1 hour to completely dissolve the vinyl chloride/vinyl acetate copolymer. Next, the above-mentioned ink components were added thereto and stirred for 2 hours to obtain a smooth and uniformly dispersed ink solution, thereby preparing an ink solution. This ink liquid was applied to the above examples and comparative examples, ethyl acetate and toluene were evaporated,
A heat-melting ink layer was formed to obtain a heat-sensitive transfer medium. Thermal transfer was performed using the four types of samples obtained as described above using RiFux 3300 (manufactured by Ricoh Co., Ltd.). Also,
A two-fold test was conducted on these samples. In this case, the two-fold test involves folding the sample in half with the ink layer inside, visually determining the adhesion between the ink layer and the support at the folded line, and
If it did not peel off, it was considered good; if it peeled off, it was judged as poor.
The results of these tests are shown in the table.

[Table] Solid areas are torn during transfer Transfer effect The recording layer does not peel off during transfer, so multiple transfers are possible, and since the adhesive layer can be made thinner, thermal conductivity does not decrease significantly. , a clear transferred image can be obtained.

Claims (1)

[Claims] 1 In a thermal transfer medium in which an adhesive layer is provided on a base material and a heat-melt ink layer is provided on the adhesive layer, the adhesive layer is made of one or two of nitrocellulose, acetylcellulose, cellulose acetate butyrate, and cellulose propionate. A thermal transfer medium comprising the above.