Manufacture of polyols and rigid polyurethane foam using thiodialkylene glycols

A process for the preparation of a rigid polyurethane foam which comprises reacting an excess of an aromatic polyisocyanate with a polyol component in the presence of a blowing agent, a catalyst, and a foam stabilizing agent,

• said polyol component comprising a thiodialkylene glycol modified polyester polyol condensation product of a polyalkylene terephthalate with a polyol having a molecular weight of about 500 or less, said condensation product having been prepared by digesting a polyalkylene terephthalate with from about 0.8 to about 2 molecular equivalents, based on the ethylene terephthalate groups in the polyethylene terephthalate, of a polyol having a molecular weight of about 500 or less at a temperature within the range of about 190.degree. to about 280.degree. C. and a pressure within the range of about 1 to about 40 atmospheres for a period of time within the range of about 0.5 to 5 hours while removing from the reaction product volatile condensation by-products including ethylene glycol and derivatives thereof until at least about 10 wt. % of the charge has been removed overhead, cooling the reaction mixture to a temperature within the range of about 150.degree.-190.degree. C., adding from about 20 to about 50 mole percent, based on the low molecular weight diol, of a thiodialkylene glycol and thereafter maintaining said reaction mixture within said temperature range for a period of time within the range of about 0.5 to about 5 hours to thereby provide said thiodialkylene glycol modified polyester polyol condensation product.

A process of preparing a polyurethane which comprises reacting an excess of an aromatic polyisocyanate with a polyol component in the presence of a blowing agent, a catalyst and a foam stabilizer,

• said polyol component comprising a digestion product of a polyalkylene terephthalate with a digesting component comprising a thiodialkylene glycol, said condensation product having been prepared by digesting the polyalkylene terephthalate with from about 0.8 to about 2 molecular equivalents, based on the alkylene terephthalate groups in the polyalkylene terephthalate, of a glycol having a molecular weight of about 500 or less at a temperature within the range of about 180.degree. to about 250.degree. C. and a pressure within the range of about 1 to about 40 atmospheres for a period of time within the range of about 0.5 to about 5 hours while removing from the reaction product volatile condensation by-products including ethylene glycol and derivatives thereof until at least about 10 wt. % of the charge has been removed overhead, cooling the reaction mixture to a temperature within the range of about 150.degree. to about 190.degree. C., adding from about 10 to about 90 mole percent, based on the low molecular weight diol, of a thiodialkylene glycol and thereafter maintaining said reaction mixture within said temperature range for a period of time within the range of about 0.5 to about 5 hours to thereby provide said thiodialkylene glycol modified polyester polyol condensation product, and wherein the polyol is a polyether polyol.

A polyurethane prepared by reacting an excess of an aromatic polyisocyanate with a polyol component in the presence of a blowing agent, a catalyst and a foam stabilizer, said polyol component comprising a digestion product of a polyalkylene terephthalate with a digesting component comprising a thiodialkylene glycol, said digestion product having been prepared by digesting the polyalkylene terephthalate with from about 0.8 to about 2 molecular equivalents, based on the alkylene terephthalate groups in the polyalkylene terephthalate, of a glycol having a molecular weight of about 500 or less at a temperature within the range of about 180.degree. to about 250.degree. C. and a pressure within the range of about 1 to about 40 atmospheres for a period of time within the range of about 0.5 to about 5 hours while removing from the reaction product volatile condensation by-products including ethylene glycol and derivatives thereof until at least about 10 wt. % of the charge has been removed overhead, cooling the reaction mixture to a temperature within the range of about 150.degree. to about 190.degree. C., adding from about 10 to about 90 mole percent, based on the low molecular weight diol, of a thiodialkylene glycol and thereafter maintaining said reaction mixture within said temperature range for a period of time within the range of about 0.5 to about 5 hours to thereby provide a thiodialkylene glycol modified polyester polyol condensation product, and wherein the polyol is a polyether polyol.