Method of recovering polyether polyols from polyurethane.

摘要

Polyol is recovered from polyurethane based polyurethane foam by a process which includes first dissolving the foam in a saturated alcohol, preferably diethylene glycol, having a boiling point between about 225°C and 280°C at a temperature between about 185°C and 220°C under a non-oxidizing atmosphere. The solution is reacted with water in the presence of an alkali hydroxide catalyst, preferably sodium hydroxide, under a non-oxiding atmosphere, such as nitrogen. This may be done by refluxing the solution at a temperature between 175°C and 220°C until all the carbamates produced during dissolution have been hydrolyzed to amines and alcohol. Water remaining in solution after hydrolysis is removed. A high boiling alkane is used to extract the polyol from the solution still under a non-oxidizing atmosphere and then the extracted polyol is subjected to vacuum purification at a temperature of less than about 230°C. Substantially pure polyol is recovered which can be used to make new foam.