Patent GB-1038785-A (GB)
Title: Dry transfer sheets and processes for using the same
Inventor: REED KENNETH JAMES
IPC: B41M5/10
Filed: 1963-02-26
Abstract: A dry transfer sheet comprises a carrier sheet (A), a thin coloured, uncoloured or printed transferable film layer (B) carried by the carrier sheet and being substantially or completely coextensive therewith, an adhesive layer (C) covering the film (B) and a separable protective covering layer (D) applied over the adhesive layer, the assembly being such that a line scribed on the face of sheet (A) remote from film (B) causes the fracture of film (B) in register with the line even though sheet (A) is itself not cut through.  The functional cutting relationship exhibited by the assembly is achieved by selecting a carrier sheet having a higher elongation at break point than the transferable film.  To effect the transfer of film (B), e.g. to a surface of paper, paper board, plastics, glass, wood or metals, the protective layer is removed, the transfer material is placed adhesive side down on to the receiving surface to cover, e.g. a closed outline of a design to which the transfer is to be applied, and the outline is then reproduced on the carrier sheet with a sharp instrument so that when the carrier sheet is lifted away that part of the film within the scribed outline becomes detached and adheres to the surface. Alternatively, the scribed outline may be made before the protective layer is removed. To achieve these results, the mutual adhesion at the various interfaces is arranged such that the peel bond of the carrier sheet to the transferable film is higher than the peel bond between the film and the protective sheet, and is also higher than that between the film and receiving surface under light pressure ( 1/2 p.s.i. or less), but lower than that between the film and the receiving surface under high pressure (50 p.s.i. or more).  The carrier sheet, which may have either a gloss, matt or embossed finish, may be a self-supporting film of a polymeric or similar material.  The dry transferable film preferably comprises an organic material different from that used for the carrier layer, in which may be incorporated plasticizers, dyes, pigments, stabilizers and fillers.  A uniform pattern may be printed on to the clear or coloured transferable film after its application to the carrier sheet, alternatively the carrier sheet may be printed prior to application of the film.  The ink used for the pattern may contain ceramic frits or ceramic pigments, magnetic iron oxide, conductive silver oxide or graphite particles. The product is described as being suitable for use as a photo-mechanical tint sheet, in which case the transparent film layer is overprinted with half-tone dots, line rulings, shading, hatching or stipples.  Drawings and artwork prepared with such sheets may be converted into printing plates, blocks or cylinders by direct photography.  Other uses suggested are masking, photographic masking, colour trim and for making a screen printing stencil by applying the film to a screen printing mesh and bonding it thereto irreversibly by means of a solvent.  The film may be overprinted with ceramic inks and fired after transfer to glass or ceramic articles to burn away the film and fuse the inks on to the surface.