Patent GB-1076018-A (GB)
Title: Improvements in or relating to sheet materials
IPC: B41N1/12
Filed: 1964-09-28
Abstract: A self-supporting, amorphous, complient, firm, extensible smooth thermoplastic material consists essentially of a binder which comprises a homogeneous blend of 10 to 60 parts by weight of readily extensible waxy, low density solid branched thermoplastic ethylenepolymer, 5 to 75 parts by weight of soft flexible resilient elastomer, defined as a relatively soft, weak material such as a stereospecific polybutadiene, 0 to 50 parts by weight of tough flexible elastomer, defined as a relatively harder and tougher material such as natural rubber, which can be formed into a smooth sheet, and a finely divided particulate filler, which is insoluble in water, constitutes from 1/20 to 2/3 of the volume of the material and is present in amount sufficient to keep the sheet from blocking but insufficient to permit the sheet to break when bent back sharply against itself.  The thermoplastic ethylenepolymer may be low-density polyethylene which may be a branched polyethylene having a density of about 0.92 and an average melt index of less than 300, an ethylene: vinyl acetate copolymer, an ethylene: acrylate ester copolymer, or a blend thereof. The soft flexible elastomeric polymer may be stereospecific bis - 1,4 polybutadiene rubber which may have a Mooney viscosity of about 40, chlorosulphonated polyethylene, polyisobutylene, a rubbery polyvinyl ether, an ethylene-acrylate ester polymer, ethylene-propylene polymers, or a blend thereof. The tough flexible elastomer may be natural rubber which may be a smoked sheet natural rubber, low gel nitrile rubber having a Mooney viscosity of 20 to 40, a calendering grade of styrenebutadiene rubber, a calendering grade neoprene, or a blend thereof.  The filler may be attapulgus clay, silica, diatomaceous earth, aluminium silicate platelets, cellulose fibres.ALSO:An ink-transferring sheet is formed from a self-supporting, amorphous, complient, firm, extensible smooth thermoplastic material consisting essentially of a binder which comprises a homogenous blend of 10 to 60 parts by weight of readily extensible waxy, low density solid branched thermoplastic ethylenepolymer, 5 to 75 parts by weight of soft flexible resilient elastomer, defined as a relatively soft, weak material such as a stereospecific polybutadiene, 0 to 50 parts by weight of tough flexible elastomer, defined as a relatively harder and tougher material such as natural rubber, which can be formed into a smooth sheet, and a finely divided particulate filler, which is insoluble in water, constitutes from 1/20 to 2/3 of the volume of the material and is present in amount sufficient to keep the sheet from blocking but insufficient to permit the sheet to break when bent back sharply against itself, the sheet being coated with an adhesive on one surface.  The thermoplastic ethylenepolymer may be low density polyethylene which may be a branched polyethylene having a density of about 0.92 and an average melt index of less than 300, an ethylene: vinyl acetate copolymer, an ethylene: acrylate ester copolymer, or a blend thereof.  The soft flexible elastomeric polymer may be stereospecific cis1,4 polybutadiene rubber which may have a Mooney viscosity of about 40, chlorosulphonated polyethylene, polyisobutylene, a rubbery polyvinyl ether, an ethylene-acrylate ester polymer, ethylene-propylene polymers, or a blend thereof. The tough flexible elastomer may be natural rubber which may be a smoked sheet natural rubber, low gel nitrile rubber having a Mooney viscosity of 20 to 40, a calendering grade of styrene-butadiene rubber, a calendering grade neoprene, or a blend thereof.  The filler may be attapulgus clay, silica, diatomaceous earth, aluminium silicate platelets, or cellulose fibres.  The adhesive may be a normally tacky and pressure sensitive adhesive which is protectively covered by a removable liner e.g. silicone treated paper.  The sheet may be from 1/2 to 2 mm thick. The sheet may be adhered to a rigid block, a roll, or to such supports as metal, wood, paper or cardboard.  A primer coating comprising a butadiene-styrene copolymer may be applied prior to the adhesive coating.  The ink-transferring sheet may be used in a printing operation which comprises shaping the sheet material, applying the shaped sheet material to a support in a manner which provides a surface having a predetermined pattern of areas of varying thickness, applying ink to the surface, and transferring the ink to a substrate to be printed with the pattern.