Patent GB-727825-A (GB)
Title: Transfer paper and dry-strip transfers made with such paper
Inventor: EDGE NORMAN
IPC: B44C1/17
Filed: 1952-11-20
Abstract: 727,825. Transfers. BRITTAINS, Ltd. Aug. 27, 1953 [Nov. 20, 1952], No. 29399/52. Class 140. [Also in Group XVI] A transfer comprises a strong non-delaminable backing paper peelably attached to tissue paper which is permanently attached to a translucent flexible carrier film peelably attached to the transfer film. The backing paper provides the strength and stiffness necessary for handling and printing, being stripped off prior to the transfer operation. The peeling operations do not require the use of liquids. The transfer may be made from ungummed " Duplex " transfer paper (relatively thick backing paper peelably attached to relatively thin tissue paper), the " Duplex " paper being coated to produce said film, followed by application of the transfer film in the conventional way. The carrier film may be a polyethylene, polychlorotrifluoroethylene, polystyrene, soyabean lecithin, phenol-formaldehyde, or silicone resin. In the following examples, ungummed " Duplex " transfer paper is employed. (1) A polyethylene latex dispersion is brushed on to the ungummed tissue side, dried, and fused at 160‹ C. for 2-3 minutes; the polyethylene may contain an antioxidant, and may be applied from a solution in hot xylene or other organic solvent; or by extruding hot polyethylene through a flat film die into the nip between a resilient backing roll carrying the paper and an internally water-cooled metal roller, the coated paper being carried partly round the metal roller before slitting and reeling-up. A transfer film may be formed on the polyethylene surface by brushing on a solution of a low viscosity cellulose acetate plasticized with 50 per cent by weight of diethyl phthalate in an acetone-methyl glycol mixture; other transfer films, suitable for subsequent transference to a moistened glass plate, may be formed by brushing on a solution of polyvinyl alcohol in a water-ethyl alcohol mixture, preceded or not by a nitro-cellulose lacquer plasticized with 57 per cent of trixylenyl phosphate; alternatively, a lithographic transfer may be printed on (see Group XVI). The free surface of the transfer film may be overprinted with a solvent- or heat-activatable adhesive, to obviate sizing of the receiving surface. (2) Polystyrene is brushed on as a solution in an organic solvent (e.g. 15 per cent in toluene with or without 3.5 per cent of a partly compatible additive such as butyl stearate); a cellulose acetate or polyvinyl alcohol transfer film as in example (1) may then be applied. (3) The ungummed " Duplex " paper is first coated with hydrophilic material such as starch or glue, then with a specified silicone in aqueous dispersion or in solution in aromatic hydrocarbons, ketones, &c. (e.g. a 3 per cent solution in toluol, with 2 per cent by weight of Zn of zinc 2-ethyl hexoate as catalyst), and then heated at 130‹ C. for 1 minute; a cellulose acetate or nitrocellulose transfer film as in example (1) may then be applied. Other materials for the translucent flexible film are: a polyethylene composition containing e.g. waxes or polyisobutylene or both as modifiers; polychlorotrifluoroethylene (which may be applied by extrusion-lamination); soya bean lecithin or phenol-formaldehyde resins (applied as a solution in an organic solvent).