Production of polyurethanepolyisocyanates

Claim 1

A PROCESS FOR THE PRODUCTION OF URETHANE DIISOCYANATES WHICH COMPRISES ADMIXING AT A TEMPERATURE LESS THAN 100*C. A SATURATED ALIPHATIC POLYHYDRIC ALCOHOL HAVING FROM TWO TO FOUR HYDROXYL GROUPS WITH AN ORGANIC DIISOCYANATE SELECTED FROM THE GROUP CONSISTING OF SATURATED ALIPHATIC DIISOCYANATES, SATURATED CYCLOALIPATHIC DIIOCYANATES, AND ARYLENE DIIOCYANNATES IN AN AMOUNT IN EXCESS OF THAT REQUIRED FOR THE REACTION OF ONE MOL OF SAID DIISOCYANATE WITH EACH MOL EQUIVALENT OF AN HYDROXYL GROUP CONTAINED IN SAID POLYHYDRIC ALCOHOL, EXTRACTING THE REACTION MIXTURE WITH A MEMBER HAVING A BOILING POINT OF LESS THAN 200*C. AND SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC HYDROCARBONS, ALICYCLIC HY DROCARBONS AND MIXTURES THEREOF AT A TEMPERATURE ABOVE THE MELTING POINT OF SAID REACTION MIXTURE, BUT LOW ENOUGH TO AVOID UNDESIRABLE POLYMERIZATION REACTIONS, SEPARATING THE SOLVENT LAYER FROM THE LIQUID PRODUCT LAYER OBTAINED IN THE EXTRACTION STEP AND RECOVERING A URETHANE POLYISOCYANATE FROM SAID PRODUCT LAYER.