Process for the preparation of polyurethane elastomers

Claim 1

PROCESS FOR THE PREPARING OF A SULFUR CURED POLYURETHANE ELASTOMER WHICH COMPRISES (A) FORMING A LIQUID COMPOSITION BY MIXING TOGETHER (1) X MOLES OF A GLYCOL HAVING A SIDE CHAIN BEARING A TERMINAL -CH=CH2 GROUP, (2) 0.1X TO 1.0X MOLE OF 2,2''-DITHIOBISBENZOTHIAZOLE, (3) 0X TO 1.0X MOLE OF 2-MERCAPTOBENZOTHIAZOLE, (4) 0.2X TO 5.0X MOLES OF SULFUR, (5) Y MOLES OF A GLYCOL HAVING A MOLECULAR WEIGHT NOT GREATER THAN 3500, SAID GLYCOL BEING SELECTED FROM THE GROUP CONSISTING OF ALKYLENE GLYCOLS, ALKYLENETHER GLYCOLS, ALKYLENEETHER-THIOETHER GLYCOLS, POLYALKYLENEETHER GLYCOLS, POLYALKYLENE-ARYLENEETHER GLYCOLS, AND POLYALKYLENEETHER-THIOETHER GLYCOLS AND POLYALKYLENE-ARYLENEETHER-THIOETHER GLYCOLS, (6) Z MOLES OF AN ISOCYANATE-TERMINATED POLYURETHANE HAVING A MOLECULAR WEIGHT FROM ABOUT 1070 TO 5000 AND BEING SELECTED FROM THE GROUP CONSISTING OF POLYALKYLENEETHER POLYURETHANES, POLYALKYLENE-ARYLENEETHER POLYURETHANES, POLYALKYLENEETHER-THIOETHER POLYURETHANES AND POLYALKYLENE-ARYLENEETHER-THIOETHER POLYURETHANES, SAID POLYURETHANES BEING PREPARED BY REACTING A MOLAR EXCESS OF AN ORGANIC DIISOCYANATE WITH A POLYMERIC GLYCOL HAVING A MOLECULAR WEIGHT OF FROM ABOUT 750 TO 3500; WITH THE PROVISO THAT X AND Z ARE INTEGERS GREATER THAN 0 AND Y IS AN INTEGER INCLUDING 0, WITH Z BEING ABOUT EQUAL TO THE SUM OF X AND Y; WITH THE FURTHER PROVISO THAT THE MOLE RATIO OF SULFUR TO 2,2''-DITHIOBISBENZOTHIAZOLE IS AT LEAST 1.0 AND THAT X BE SUFFICIENTLY LARGE SO AS TO PROVIDE AT LEAST ONE SIDE CHAIN BEARING A TERMINAL -CH=CH2 GROUP FOR EVERY 12,000 MOLECULAR WEIGHT UNITS OF POLYURETHANE ELASTOMER WHICH IS OBTAINED FROM THIS LIQUID COMPOSITION; AND (B) HEATING SAID MIXTURE TO A TEMPERATURE OF FROM ABOUT 130 TO 170* C. UNTIL A CURED ELASTOMER IS OBTAINED.