PROCESS FOR PRODUCING TRANSFER ELEMENTS

摘要

1382367 Transfer elements COLUMBIA RIBBON & CARBON MFG CO INC 7 Nov 1972 [29 Dec 1971] 51304/72 Heading D2B A process for producing a liquid ink-releasing transfer element comprises (a) preparing a composition comprising a synthetic thermoplastic resin, a solid pore forming material, and a volatile liquid vehicle, (b) coating a thin layer of the composition onto a flexible foundation and evaporating the vehicle to form a solidified layer of the resin containing the solid pore-forming material thereon, (c) removing the solid pore-forming material from the layer to form a porous, resin layer, and (d) impregnating the porous layer with a liquid non-drying ink. In a modification, a thin intermediate bonding layer of a synthetic thermoplastic resin may be formed on the flexible foundation prior to the application of the composition referred to in (a) above. Such a bonding layer may be porous. A liquid poreforming material may also be included in the composition referred to in (a) above. In Example 1, the pore-forming coating composition comprises an ethanolic polyamide solution containing salicylic acid as the pore-forming agent. The coating composition is applied to a polyethylene terephthalate film and the ethanol is evaporated off. The coated film is then heated to 90‹C to sublime the salicylic acid, thereby forming a porous nylon-coated film. The porous coating is then impregnated with a conventional duplicating ink comprising carbon black, mineral oil, butyl stearate, and mineral spirits. In Example 2, a pore-forming coating composition comprising a vinyl chloride/vinyl acetate copolymer solution containing sodium chloride, heptane, and methyl ethyl ketone is applied to a polyethylene terephthalate film carrying a porous nylon bonding layer. The methyl ethyl ketone and heptane are evaporated off sequentially and the sodium chloride is leached out with water to produce a coating having the desired porosity. The coating is then inked as previously. In Example 3, the pore-coating composition comprises an aqueous emulsion of a polyurethane resin containing N, N'-dimethyl-N, N'-dinitroso terephthalamide as a pore-forming agent.