| 摘要 |
1,161,746. Laminates. FARBENFABRIKEN BAYER A.G. 1 Nov., 1966 [5 Nov., 1965], No. 48981/66. Heading B5N. [Also in Divisions B2 and C3] Microporous polyurethane sheet structures permeable to water vapour are prepared by the reversal process by spraying on to a support a solution of 3 to 50% solids content and a Ford viscosity of 10 to 120 sec. (4 mm. outflow nozzle at spray temperature) of the following components: (a) a reaction product of (i) a poly- (thio)ether and/or a poly(thio)ether urethane or urea containing hydroxyl and/or amino groups and having a M.W. of 500 to 20,000; (ii) if desired, a chain extender of M.W. below 500 and (iii) a polyisocyanate in an amount of 90 to 150% based on the total reactive hydrogen atoms and comprising 0À03 to 0À5 equivalent per cent of the reaction product; (b) 2 to 50% by weight of (a) of a polyisocyanate and/or formaldehyde or a formaldehyde donor; and (c) if desired up to 50 equivalent per cent excess, based on polyisocyanate (b) of a further compound reactive with isocyanates, in an organic solvent which has a b.p. below 120‹ C. discontinuously through a stream of gas not more than 80‹ C. below the b.p. of the solvent, the solution being subdivided by the stream of gas and 40 to 99% of the solvent evaporating before the solution reaches the support, the solidified foil on the support being provided with discontinuous layers of adhesive and transferred by the reversal process to other porous substrates. In the examples a chromed steel plate is spray coated with one of a number of the compositions of the invention, the resulting structure dried and the surface lightly ground. This ground surface and a ground surface of a split leather are then covered with a discontinuous layer of adhesive, the two surfaces pressed together and compressed. The sheet structure is then heated, cooled and the leather together with the microporous polyurethane sheet adhered to it stripped from the steel plate. |
