Polyurethane prepn. from trans-cyclohexane-1,4-di:isocyanate

摘要

Polymethanes are obtd. by reaction of cyclohexane-1, 4-di-isocyanate macrodiols of average mol.wt. 800-4000, prepd. from monomer of >90% trans-isomer content, with a low-mol.wt.chain-lengthening agent contg. is not <2 active H atoms.Pref. the trans-isomer content is >=95%, esp. >=99%. Pref. reaction is between polybutylene adipate, poly-2,2,4-trimethylhexyl(1,6)ine or polytetramethyleneglycol with an aliphatic glycol contg. 2-4C as chain-lengthening agent. Other suitable agents are hydrazine or a deriv. contg. an active H on each N atom, and diamines, pref.cycloaliphatic cpds., esp. trans-cyclohexane-1,4-diamine. Pref.polyesters used are those that do not crystallise at room temp.Polyesters contg. OH grps. are suitable macrodiols, e.g. those based on adipic acid and (a) short-chain aliphatic glycols of 2-6C and long-chain glycols of 6-10C, (b) branched- and straight-chain glycols, or (c) 2,2,4-trimethylhexane(1,6)diol.The polymers are used to mfr. machine and vehicle parts, tyres, insulating nets, foams, lacquers, coatings, fibres, filaments, sheets, hydraulic elements etc. Compared with previously known polymethanes, including those obtd. from cyclohexane-1,4-di-isocyanate of <85.5% transisomer content, the prods. have higher softening pts., lower glass-transaction temps., higher ability to withstand large forces with minimal stretching, high hardness, good abrasion resistance, good fastness to light and high resistance to many solvents