Use of liquid oxazolines in polyurethane/polyisocyanurate rigid foams as reactive compatibilizers

Claim 1

A rigid cellular foam comprising the cured reaction product of a polyisocyanate with between about 0.1 and about 1.0 hydroxyl equivalent of polyol per equivalent of said polyisocyanate, said polyol comprising at least about 60 percent polyol mixture prepared by the transesterification with a glycol of molecular weight from about 60 to 400 of a residue remaining after dimethyl terephthalate and methyl p-toluate have been removed from a dimethyl terephthalate esterified oxidate reaction product, the major portion of said residue comprising a mixture of methyl and benzyl esters of benzene and biphenyl di- and tricarboxylic acids, said reaction of polyisocyanate and polyol taking place in the presence of (a) isocyanate trimerization catalyst; (b) fluorocarbon blowing agent; and (c) between about 1 and 50% by weight based on total polyol of oxazoline of the formula ##STR2## wherein R, R', R"' and R"" independently represent hydrogen, an alkyl group containing from 1 to 10 carbon atoms, or a hydroxy alkyl group having from 1 to 10 carbon atoms and R" represents hydrogen, an alkyl group containing from 1 to 19 carbon atoms, an aryl group containing from 6 to 12 carbon atoms or a hydroxy alkyl group containing from 1 to 19 carbon atoms.