polyurethanes and their preparation segmentes lineaires

摘要

1286389 Linear segmented polyurethanes FARBENFABRIKEN BAYER AG 14 Oct 1970 [17 Oct 1969] 48770/70 Heading C3R [Also in Division C2] Linear segmented polyurethanes contain at least 5 mol. per cent, based on the chain extension segment present, of a chain extension segment of the formula in which R represents a radical of the formula -(CH 2 ) x -, wherein x is 1 or 2 or of the formula wherein y is 0, 1 or 2, and may be prepared by reacting an isocyanate preadduct obtained from a dihydroxy compound with a molecular weight of 500 to 6000, optionally a diol having a M.W. of 62 to 300 and containing optionally one or more tertiary aliphatic amino groups, and a molar excess of a diisocyanate with a substantially equivalent quantity of a bifunctional chain extending agent, at least 5 mol. per cent of which is a monourea hydrazide of the formula wherein R is as above, in the presence of a highly polar organic solvent, and then removing the solvent. The isocyanate preadduct is suitably prepared from a polyester, polycarbonate or polyether and an aromatic diisocyanate. In specific examples, the chain extending agent is urea-N,NSP1/SP-diacetic acid hydrazide, urea-N,NSP1/SP- dipropionic acid hydrazide, urea -N,NSP1/SP-diphenyl- 4,4SP1/SP-carboxylic acid hydrazide, urea-N,NSP1/SP-diphenyl-4,4SP1/SP-diacetic acid hydrazide or urea- N,NSP1/SP - diphenyl - 4,4SP1 /SP- propionic acid hydrazide. Filaments or films may be produced from the polymer solutions.