Patent GB-638774-A (GB)
Title: Improvements in and relating to the production of decorative artificial films and sheets
IPC: B29D7/01
Filed: 1948-02-23
Abstract: A wrinkled decorative film or sheet is obtained by forming on a smooth support a layer of a solution of a transparent film-forming material in about 5-15 times its weight of a volatile solvent, in which is dispersed an insoluble pigment other than a metal powder, and evaporating the solvent at such a rate that wrinkling of the film takes place and the pigment migrates to the crests.  The crests may be translucent and the troughs transparent, or if more pigment is used the crests may be opaque while the troughs are transparent or translucent.  The film-forming substance may be a cellulose ester or ether or a synthetic resin such as a polyvinyl ester or polymethacrylic ester.  A plasticizer may be included in the solution.  Acetone or methylene chloride may be used as solvent.  The pigment may be titanium dioxide or an organic pigment.  Mica or similar reflecting substance may be used in conjunction with the pigment.  The pigment may be present in the solution to the extent of 0.5 to 3 per cent for translucent crests and of about 4 to 10 per cent for opaque crests and transparent or translucent troughs.  The solution may be cast on a glass plate or moving band and the solvent may be evaporated freely in air at room temperature or temperatures up to 60 DEG  C.  To prevent flowing p  of the cast solution during the first stages of evaporation, the sheet may be supported at the sides, e.g. by endless belts forming side walls.  These may move away from the casting surface as soon as the film is self-supporting.  The wrinkled film may be treated with a dyestuff for the film-forming material.  Two-colour effects may thus be obtained since the crests containing the pigment are coloured differently from the troughs. Dyeing may be effected by padding the sheet with a solution of dye in an organic solvent. In an example, a solution of cellulose acetate in acetone containing dimethyl phthalate, Monastral Fast Green GS and titanium oxide, is cast as a sheet on a glass plate with glass side supports.  The sheet is exposed to air at 27 DEG  C.  During removal of the solvent the sheet becomes wrinkled, the crests being translucent and of thickness 12 mils, and the troughs being transparent and of thickness 6 mils.  In another example, Monastral Fast Blue GS mixed with titanium dioxide is used as pigment.  The wrinkled film is then padded at 35 DEG  C. with a dyebath comprising Dispersol Fast Yellow A, acetic acid, methylated spirit and water. After removal of surplus liquor and partial drying, the sheet is passed through a bath comprising soap, the sodium salt of a long chain alkyl sulphate and ammonia, and then through a cold water bath. The wrinkled sheet has a two-colour effect in which the crests are green and the troughs are yellow.  Other examples describe the use of other pigments, including Irgalite Cerise 6 BN and Monolite Fast Yellow GNS, and subsequent dye baths containing other dyestuffs, e.g. Duranol Brilliant Blue B and Dispersol Fast Scarlet B.  In another example, a wrinkled sheet is obtained from a solution of a copolymer of vinyl chloride and vinyl acetate.  Specification 592,633 is referred to.ALSO:A film or sheet which has been formed from a pigmented solution in such manner that it has a wrinkled surface and that the pigment has migrated to the crest portions leaving the trough portions only slightly pigmented if at all (see Group IV (a)), is subjected to a dyeing treatment.  Differential colouring or shading may thus be obtained.  The pigment may be white or coloured and may be a mineral pigment or organic dyestuff.  It may be titanium dioxide with or without an organic dyestuff.  Light reflecting substances such as mica may be used in conjunction with the pigment. Dyeing p  may be effected by padding the film with a solution of dye in an organic solvent.  The film-forming substance may be a cellulose ester or ether or a synthetic resin such as a polyvinyl ester or polymethacrylic ester.  In an example, a solution of cellulose acetate containing Monastral Fast Green GS, and titanium dioxide, is cast on a glass plate, and the solvent is evaporated in air at 27 DEG C. so that the sheet becomes wrinkled, the crests being translucent and the troughs transparent.  In another example, Monastral Fast Blue GS mixed with titanium dioxide is used as the pigment.  The wrinkled film is padded with a dyebath comprising Dispersol Fast Yellow A, acetic acid, methylated spirit, and water.  After removal of surplus liquor and partial drying, the sheet is passed through a bath comprising soap, the sodium salt of long chain alkyl sulphate, and ammonia, and is then passed through a cold water bath.  The wrinkled sheet has a two-colour effect in which the crests are green and the troughs are yellow.  Other examples describe the use of other pigments, e.g. Irgalite Cerise 6 BN, and Monolite Fast Yellow GNS, and subsequent dye baths containing other dyestuffs, e.g. Duranol Brilliant Blue B, and Dispersol Fast Scarlet B.  Specification 592,633 is referred to.