Coating pastes containing PU plastics and process for the production of water vapour-permeable polyurethane coatings

摘要

The coating pastes are multiphase, stable mixtures of A) 5-50% by weight of hydrophobic polyurethanes and/or polyurethane ureas per se which contain incorporated 1-30% by weight of synthesis components from the silicone resin group, the polyethers or polyesters containing aromatic molecular segments and/or the perfluorocarbon resins, B) 0-30% by weight of hydrophobic polyurethane(urea)s per se, which are synthesised without the special synthesis components mentioned in A), C) 4.5-50% by weight of organic solvents for A) and B), D) 0-40% by weight of organic non-solvents for A) and B), E) 0-10% by weight, preferably 0.5-5% by weight, of polymers which are free of urethane and urea groups and carry carboxyl groups completely or partially neutralised with bases, F) 10-70% by weight of water and G) 0-5% by weight of crosslinking agents, hydrophobicising agents, stabilisers against discoloration and degradation and/or other coating auxiliaries. The coating pastes are used in the direct or transfer process for the production of water vapour-permeable coatings by the principle of evaporative coagulation.