| 摘要 |
1,246,092. Thermographic transfer processes. AGFA GEVAERT. Sept.10, 1968 [Oct.2, 1967], No.44794/67. Heading G2C. A thermographic transfer process wherein a heat-sensitive material comprising a support bearing a water-permeable layer which contains hydrophobic thermoplastic particles dispersed in a hydrophilic binder is imagewise heated rendering the heated areas less water permeable or water impermeable, developed to remove the unheated water-permeable areas and then pressed partly or entirely into contact with a receptor sheet to transfer some or all of the heated areas. Preferred heat-sensitive materials are those of Specifications 1,139,891 and 1,160,221. To assist the transfer, the support may be coated with a subbing layer as in Specification 1,177,481 before applying the heat-sensitive layer. In the Examples, a polyester support is coated with a subbing layer of polyethylene particles and silica dispersed in a vinylidene chloride copolymer or polyethylacrylate and is overcoated with a heatsensitive layer of polyethylene particles and carbon black alone or dispersed in polyvinylpyrrolidone is imagewise exposed to a flash lamp and the unheated areas are washed off. The material is contacted with a receptor sheet and the back of the material rubbed to transfer the heated areas of the heat-sensitive layer to the receptor sheet. The heat-sensitive layer may be overcoated with a layer of butyl acrylate/vinyl acetate copolymer or polyisobutyl methacrylate to assist transfer to the receptor sheet. The heat-sensitive layer may contain a water-insoluble pigment and thus give a coloured image on transfer. If three heat-sensitive layers containing yellow, cyan and magenta pigments are imagewise exposed to the appropriate colour separation negatives and transferred in register to the receptor sheet, a colour proof is obtained.
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