1. A METHOD FOR FORMING A THERMOPLASTIC POLYURETHANE HAVING FREE -NCO GROUPS AND A MELTING POINT OF FROM ABOUT 60 TO ABOUT 250*C. WHICH COMPRISES MIXING THE REACTIVE COMPONENTS OF SAID POLYURETHANE WHICH CONTAIN AN EXCESS OF -NCO GROUPS COMPRISING AN EXCESS OF AN ORGANIC POLYISOCYANATE AND AN ORGANIC COMPOUND CONTAINING AT LEAST TWO ACTIVE HYDROGEN CONTAINING GROUPS AS DETERMINED BY THE ZEREWITINOFF METHOD, PASSING THE REACTION MIXTURE THROUGH A PASSAGEWAY WHILE MAINTAINING THE TEMPERATURE IN SAID PASSAGEWAY WITHIN THE RANGE OF FROM ABOUT 60*C. TO ABOUT 250*C. AT A RATE SUCH THAT THE RESIDENCE TIME IN THE PASSAGEWAY IS LESS THAN SUFFICIENT TO CAUSE REACTION OF ALL OF THE -NCO GROUPS IN SAID MIXTURE OF REACTIVE COMPONENTS, AND REMOVING THE RESULTING POLYURETHANE FROM SAID PASSAGEWAY TO A ZONE WHERE FURTHER REACTION OF THE -NCO GROUPS IS AVOIDED TO PRODUCE A PRODUCT HAVING A MELTING POINT WITHIN THE RANGE OF ABOUT 60 TO ABOUT 250*C.