| abstract |
The present invention relates to waterproof but breathable flat materials prepared from the melt from polymer resin mixtures consisting of at least two different melt processable polyurethanes, wherein the different thermoplastic polyurethanes have soft segments with different chemical constitutions, wherein the thermoplastic polyurethane which forms the matrix is a polyurethane with a ether based soft segment, wherein the ether segment has a carbon/oxygen atomic ratio of at least two and at most three and is present at a rate of 70-95 wt. % with reference to the total weight of thermoplastic polyurethanes used for melt processing to produce a flat material, and wherein the flat materials according to the invention have a higher permeability to water vapour, determined according to DIN 53 122, and a lower water absorption, determined according to DIN 53 495, method C, than flat materials made from one of the polyurethanes used for the polymer resin mixture. |