Vulcanization composition for unsaturated polymers

Abstract

The present invention relates to the field of vulcanization of unsaturated polymers, in particular halogenated, and more particularly chlorinated, unsaturated polymers, such as, for example, polychloroprene, using as vulcanization agent a mixture of bis(2,5-dimercapto-1,3,4-thiadiazole) and at least one organic base. The present invention relates to the process for vulcanization of said polymers with said vulcanization mixture.

What is claimed: 
     
         1 . A composition for the vulcanization of unsaturated polymers, comprising a mixture of bis(2,5-dimercapto-1,3,4-thiadiazole) and at least one organic base. 
     
     
         2 . The composition according to  claim 1 , wherein the at least one organic base is chosen from nitrogenous organic bases. 
     
     
         3 . The composition according to  claim 2 , wherein the at least one organic base comprises a guanidine. 
     
     
         4 . The composition according to  claim 2 , wherein the at least one organic base comprises a substituted guanidine. 
     
     
         5 . The composition according to  claim 12 , wherein the at least one organic base is a guanidine substituted by one or more aryl groups. 
     
     
         6 . The composition according to  claim 4 , wherein the at least one organic base comprises diphenylguanidine. 
     
     
         7 . The composition according to  claim 1 , wherein the bis(2,5-dimercapto-1,3,4-thiadiazole) to organic base molar ratio is between 1:99 and 99:1. 
     
     
         8 . The composition according to  claim 7 , wherein the bis(2,5-dimercapto-1,3,4-thiadiazole) to organic base molar ratio is between 25:75 and 75:25. 
     
     
         9 . The composition according to  claim 7 , wherein the bis(2,5-dimercapto-1,3,4-thiadiazole) to organic base molar ratio is approximately 50:50. 
     
     
         10 . A process for the vulcanization of an unsaturated polymer, comprising:
 mixing the unsaturated polymer with a mixture of bis(2,5-dimercapto-1,3,4-thiadiazole) and at least one organic base, and   vulcanizing the unsaturated polymer.   
     
     
         11 . The process according to  claim 10 , wherein mixing the unsaturated polymer with a mixture of bis(2,5-dimercapto-1,3,4-thiadiazole) and at least one organic base further comprises mixing the unsaturated polymer with sulphur and/or one or more inorganic vulcanization agents. 
     
     
         12 . The process according to  claim 10 , further comprising adding one or more additives chosen from lubricants, fillers, colourants, preservatives, antioxidants, heat stabilizers, UV stabilizers, and vulcanization inhibitors or retardants. 
     
     
         13 . The process according to  claim 10 , wherein the unsaturated polymer is chosen from natural, artificial or synthetic rubbers, poly(butadienes), styrene and butadiene copolymers (SBRs), acrylonitrile and butadiene copolymers (NBRs), ethylene/propylene/diene copolymers (EPDMs), butyl rubbers, poly(styrene-butadiene styrene) copolymers (SBSs), halogenated polyalkadienes, and mixtures thereof. 
     
     
         14 . The process according to  claim 13 , wherein the unsaturated polymer comprises a chlorinated polyalkadiene. 
     
     
         15 . The process according to  claim 13 , wherein the unsaturated polymer is chosen from chloroprene rubbers or polychloroprenes, chlorinated natural rubbers, chlorinated polyolefins, chlorinated butyl rubbers, and mixtures thereof. 
     
     
         16 . The process according to  claim 15 , wherein the unsaturated polymer comprises polychloroprene.