POLYURETHANE-UREA ELASTOMERS PREPARED FROM 4,4'-METHYLENE BIS (CYCLOHEXYL-ISOCYANATE),NEOPENTYL ADIPATE AND AN AROMATIC DIAMINE

摘要

1,233,300. Polyurethane elastomers. ALLIED CHEMICAL CORP. 22 Dec., 1969 [28 Jan., 1969], No. 62492/69. Heading C3R. Polyurethane elastomers having improved hydrolytic stability and extended pour time are obtained by reacting an aromatic diamine of the formula H 2 N-X-NH 2 (wherein X represents an arylene or bis-(arylene) alkane group free from halogen substituents and optionally substituted by up to 4 C 1-4 alkyl or alkoxy groups) with an isocyanate-terminated prepolymer derived from polyneopentyl adipate and 4,4SP1 /SP- methylene - bis - (cyclohexylisocyanate). The polyneopentyl adipate is a hydroxy terminated polyester obtained by reaction of excess neopentyl glycol with adipic acid, and preferably has a molecular weight of between 500 and 3000 and an acid number of below 20. Suitable aromatic diamines include methylenedianiline, meta - phenylenediamine, 2,4 - toluenediamine, 3,31 - dimethyl - 4,41- diphenylmethanediamine, 3,3SP1/SP - dibutyl - 4,41- diphenylmethanediamine, 3,3SP1 /SP- diethyl - 4,4SP1/SP- biphenyldiamine, 3,31 - dimethyl - 4,41 - biphenyldiamine, 3,31 - dimethoxy - 4,41 - biphenyldiamine, butoxy - 2,4 - phenylenediamine, para - xylylenediamine, 2,4 - diaminoanisole, ethoxy - 2,4 - phenylenediamine and naphthylenediamines. The prepolymer preferably has an NCO/OH ratio of between 1À5 and 3À0, and the aromatic diamine is preferably used in 35 to 100% of the stoichiometric amount required to react with all the available NCO groups. After curing, further post curing may be effected at 100‹ C.