COATING AND FINISHING AGENT FOR LEATHER, AND LEATHER SUBSTITUTE BASED ON A POLYURETHANE-POLYUREA COATING COMPOSITION

摘要

This invention relates to coating agents and dressing agents for leather and leather substitutes with improved resistance to plasticizer migration, greater hardness and folding strength, a dry hand and resistance to aqueous alcoholic solutions, based on linear or only slightly branched thermoplastic polyurethane ureas built up from the following components (A) at least two macrodiols in a molar ratio of from about 1:6 to 6:1, one of which macrodiols (1) has an average molecular weight of from about 254 to 650 and contains at least one benzene, cyclohexane or cyclohexene ring, while (2) the second macrodiol has an average molecular weight in the range of from about 1200 to 3000 but has at least three times the molecular weight of A/l, and which contain (B) from about 0.5 to 11 mol of chain lengthening agent per mol of macrodiol mixture, at least about 50 mol % of the chain lengthening agents used being aliphatic and/or cycloaliphatic diamines and/or hydrazine, and in which (C) the diisocyanates used are cycloaliphatic diisocyanates, up to about 50 mol % of which may be replaced by aliphatic and/or aromatic diisocyanates.