Molded rigid polyurethane foams prepared from aminoalkylpiperazine-initiated polyols

摘要

This invention is an improvement in a process for preparing a molded rigid polyurethane or polyurethane-polyurea foam wherein a polyol having an average of at least 3 hydroxyl groups per molecule is reacted with a polyisocyanate in a mold in the presence of a blowing agent under conditions such that a rigid polyurethane or polyurethane-polyurea foam is formed. The improvement comprises employing as all or a portion of said polyol an aminoalkylpiperazine-initiated polyol having an equivalent weight from about 87 to about 500, said aminoalkylpiperazine-initiated polyol being employed in an amount sufficient to increase the cure rate of the foam relative to a similar foam prepared in the absence of the aminoalkylpiperazine-initiated polyol. Excellent flowability k-factors and rapid cures are obtained according to the invention.