A PROCESS FOR THE PRODUCTION OF ARTIFICIAL LEATHER BASED ON POLYURETHANE FOAM

1,211,339. Polyurethane foam laminates. FARBENFABRIKEN BAYER A.G. 17 July, 1969 [22 Aug., 1968], No. 36030/69. Heading B5N. [Also in Divisions B2 and C3] In a method of producing a polyurethane foam artificial leather a foamable reaction mixture comprising (a) a reaction product containing hydroxyl groups and derived from a polyhydroxyl compound with a molecular weight of from 500 to 5000 and a polyisocyanate; (b) a polyisocyanate; (c) a polyvalent heavy metal salt; (d) an expanding agent that gives off gases under the effect of heat; and (e) a polysiloxane, is heated and the resulting foam is combined with a textile supporting material, or the foamable reaction mixture is applied to a pre-coated textile supporting material and heated. The preferred component (a) is a polyester urethane containing hydroxyl groups and is the reaction product of a polyester derived from adipic acid diethylene glycol and a triol, with a polyisocyanate obtained by reacting trimethylolpropane with tolylene diisocyanate. Other preferred components are (c) a zinccadmium salt; (d) azodicarbonamide; and (e) a silicone oil with organofunctional groups. The textile supporting material is a woven fabric, knitted fabric, or web of a natural or synthetic fibre. The textile may be pre-coated with a polyurethane. A covering layer, e.g. of a polyurethane, is applied to the foam and then further coated with a butadiene-styrene-acrylonitrile copolymer and then a finish of a solution of a cross-linkable silicone oil or acrylic or methacrylic ester copolymers or a pigmented solution of a cellulose acetobutyrate is applied. When a sheet of foam is combined with the textile support the procedure is: a separating substrate, e.g. an embossed silicone separating paper or a fabric coated with a silicone rubber, has a covering layer of a butadiene-styreneacrylonitrile copolymer applied to it, and then further coated with a polyurethane, and then coated with the foamable reaction mixture of the invention, the material is then foamed and the resultant sheet of foam is coated with a layer of polyurethane adhesive which is then applied to a knitted cotton fabric and the parting film is removed.