GB1230465A - - Google Patents

Abstract

1,230,465. Coated sheet material. GLANZSTOFF A.G. 18 Sept., 1968 [20 Dec., 1967], No. 44268/68. Heading B2E. Imitation leather is produced by allowing an unwoven fibre structure which has been bonded by impregnation with a binder and dried to absorb 50-80% by weight (based on the dry impregnated structure) of water, and then coating with an elastomeric polymer gel which is then coagulated. The bonded structure may be split and/or buffed before being moistened and coated. The fibre structures can be carded or can be produced on paper-making machines or by deposition from air streams. Fibre structures which contain a woven or knitted insert may also be used. Polyurethane gels which contain polyvinyl chloride or a copolymer of vinyl chloride can be used as a surface layer composition and can be applied by doctoring or with a roller. In an example a bonded unwoven structure produced from a mixture of synthetic fibres on a paper-making machine is subjected to a shrinking process and then bonded by impregnating with a solution of polyurethane and dimethyl formamide. The impregnated structure is then coagulated with water, washed with a solvent and dried. The impregnated structure is then buffed or abraded, moistened by dipping in water and wrung out to produce a moisture content of 65% by weight based on the dry impregnated structure, and then coated using a roller-type doctor with a polyurethane solution which has been transformed into a gel-like form by adding a non-solvent. The coated material is then conducted through a bath to coagulate the surface layer, and the residual solvent washed out with water and the coated structure dried and finished.