Process for recovering secondary polyols from polyadducts mixed with nonglycolysable materials

Process for reprocessing plastic waste material made of polyaddition products of diols and diisocyanates and plastic wastes from the production of the polyaddition product, wherein for reprocessing waste which is mixed with or joined to nonglycolysable constituents, the reaction to form a secondary polyol comprises the steps of:

• a) subjecting comminuted starting material at a temperature of from about 150.degree. to 250.degree. C. for about 1 to 15 minutes with a first addition of at least one glycol in a weight ratio of 1 part glycol for 10 parts to 1 part starting material to shear force, wherein the nonglycolysable constituents are further comminuted and dispersed and glycolysable materials are glycolysed to produce a preproduct,
• b) further glycolyzing the preproduct in a spatially separate treatment vessel at a temperature from about 150.degree. to 280.degree. C. for about 30 to 150 minutes with constant stirring, resulting in a preglycolysate which is subsequently homogenized,
• c) making a second addition of at least one glycol in a weight ratio of 1 part glycol for 10 parts to 1 part preglycolysate, and further glycolyzing the preglycolysate for an additional about 30 to 150 minutes at the same temperature, stirring constantly, to produce the secondary polyol, wherein the nonglycolysable materials are further dispersed.