Process for polyol recovery from polyurethane foam comprising alcohol and steam hydrolysis

摘要

Polyol is recovered from polyether based polyurethane foam by a process which includes reacting the foam with an alcohol, preferably a glycol ether, whose boiling point is between 225 DEG C. and 280 DEG C. at a temperature between 185 DEG C. and 220 DEG C. under a non-oxidizing atmosphere. Thereafter, superheated steam is bubbled through the solution to hydrolyze substantially all the carbamate produced during dissolution to amines and alcohols, preferably in the presence of sodium hydroxide. During hydrolysis, the temperature of the solution is maintained at between 185 DEG C. and 220 DEG C. and the solution volume is maintained by adding alcohol to replace that removed by the steam. At least a portion of the solution is subjected to vacuum purification at a temperature below about 230 DEG C. The portion of the solution subjected to vacuum purification may be the polyol layer which forms after the hydrolyzed solution has been allowed to stand. Substantially pure polyol is recovered.