Improvements in or relating to the production of polyurethane elastomers

摘要

A process for the production of a stable diterminally unsaturated linear polyurethane elastomer comprises heating together n moles of a saturated polymeric dihydroxy compound having a molecular weight which is between 750 and 10,000 inclusive, n+1 moles of an organic diisocyanate, and 2 moles of a diethylenically unsaturated monohydric alcohol of formula: where A is a saturated trivalent radical; Z1 is H-(CH2)n1-CH=CH-(CH2)n2; Z2 is H-(CH2)m1 -CH=CH-(CH2)m2-; n1 and m1 are 0, 1 or 2 and n1 plus n2 and m1 plus m2 are 0 or integers from 1 to 8 inclusive. The reaction mixture may also contain an ethylenically unsaturated dihydric alcohol of formula: where A1 and A2 are saturated tri- and tetravalent radicals respectively; Z is H-(CH2)n3-CH=CH-(CH2)n4; Z1 is H-(CH2)n1-CH=CH-(CH2)n2-; Z2 is H-(CH2)m1-CH=CH-(CH2)m2-; n3, n1 and m1 are 0, 1 or 2 and n3 plus n4, n1 plus n2 and m1 plus m2 are 0 or integers from 1 to 8 inclusive. Specified diethylenically unsaturated alcohols are diallyloxypropanol, allyl propenyl carbinol, allyl vinyl carbinol and diallyl carbinol. Specified ethylenically unsaturated dihydric alcohols are 2-allyloxy-propane-1:3-diol, 1:-5 hexadiene-3:4-diol; 2:6-octadiene-4:5-diol, 1-butene-3-4-diol and 2-pentene-4:5-diol. The elastomers may be vulcanized by heating under pressure in the presence of an organic peroxide e.g. dicumyl peroxide. In the examples, polyesters made from ethylene glycol, propylene glycol and adipic acid are reacted with:-(1) diallyloxy propanol and 4:41-diphenylmethane diisocyanate; (2) diallyloxy propanol, allyloxy, propanediol and 4:41-diphenyl methane diisocyanate; (3) allyloxy propanediol, diallyloxy propanol and 3:31-dimethyl-4:41-biphenylene diisocyanate; (4) and (6) diallyloxy propanol and 4:41-diphenylmethane diisocyanate and (7) and (8) allyl vinylcarbinol and 4:41-diphenylmethane diisocyanate.