GB1172145A - Transfer Material - Google Patents

Abstract

1,172,145. Transfers. D. H. HERITAGE, and F. J. MORLEY. 11 Jan., 1967 [20 Jan., 1966], No. 2698/66. Heading B6C. [Also in Divisions C3 and C5] A transfer material comprises a carrier sheet bearing pressure transferable indicia formed of a material which is ink receptive and water repellant so that a lithographic plate may be prepared by application of the carrier sheet to the plate and transferring the indicia on to the plate by applying pressure to the rear of the sheet. The carrier sheet is preferably transparent or translucent, and may be tracing paper impregnated or coated with a wax or silicone release agent, or may be of plastics material such as cellulose acetate, polystyrene or polyethylene which may be coated with a release layer. Alternatively, the sheet may he opaque coated paper on which the indicia are repeated on the reverse face in register with those on the front to aid correct transfer. Tear lines may be defined in the carrier sheet so that one symbol may be selected and accidental transfer prevented, or a transparent or translucent protector sheet, e.g. coated with silicone, may be used for this purpose. The material forming the indicia is paste based solely on an ink comprising a pigment, e.g. carbon black, dispersed in a film forming material such as cellulose acetate and dissolved in an organic solvent, e.g. cyclohexanone, or a chloro-sulphonated polyethylene dispersed in aromatic and ketone solvents, and a wax which may be natural, e.g. beeswax or petroleum derived wax, or synthetic, e.g. polyethylene, polyethylene glycol or modified polyethylene glycol waxes. The wax content is not more than 95% by weight and preferably between 25 and 65%. In an example, the indicia material comprises 10% petroleum derived wax, 45% cyclohexanone and 45% cellulose acetate ink, and the transfer sheet is prepared by printing the indicia on a carrier sheet by a silk screen process and excess solvent allowed to evaporate by standing in air, or by using warm air. In preparing a lithographic plate, the indicia are applied thereto and the plate is heated to a temperature in the range of 120‹ to 200‹ F. for 5 to 30 seconds, the heat being applied to the back of the plate by radiation or convection.