Vulcanization composition for unsaturated polymers
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.
1. A composition for the vulcanization of chlorinated polyalkadienes, comprising a mixture of
a chlorinated polyalkadiene,
bis(2,5-dimercapto-1,3,4-thiadiazole),
sulphur, and
at least one organic base,
wherein the organic base comprises a guanidine substituted by one or more aryl groups,
wherein the composition does not comprise a zeolite, and
wherein the bis(2,5-dimercapto-1,3,4-thiadiazole) to organic base molar ratio is between 25:75 and 75:25.
2. The composition according to claim 1 , wherein the at least one organic base is a guanidine substituted by two aryl groups.
3. The composition according to claim 1 , wherein the at least one organic base comprises diphenylguanidine.
4. The composition according to claim wherein the bis(2,5-dimercapto-1,3,4-thiadiazole) to organic base molar ratio is approximately 50:50.
5. A process for the vulcanization of a chlorinated polyalkadiene, comprising:
mixing the chlorinated polyalkadiene with a mixture of bis(2,5-dimercapto-1,3,4-thiadiazole), sulphur, and at least one organic base, wherein the organic base comprises a guanidine substituted by one or more aryl groups, wherein the mixture does not comprise a zeolite and wherein the bis(2,5-dimercapto-1,3,4-thiadiazole) to organic base molar ratio is between 25:75 and 75:25, and
vulcanizing the chlorinated polyalkadiene.
6. The process according, to claim 5 , wherein mixing the chlorinated polyalkadiene with a mixture of bis(2,5-dimercapto-1,3,4-thiadiazole) and at least one organic base further comprises mixing the chlorinated polyalkadiene with sulphur and/or one or more inorganic vulcanization agents.
7. The process according to claim 5 , further comprising adding one or more additives chosen from lubricants, fillers, colourants, preservatives, antioxidants, heat stabilizers, UV stabilizers, and vulcanization inhibitors or retardants.
8. The process according to claim 5 , wherein the chlorinated polyalkadiene is chosen from chloroprene rubbers or polychloroprenes, chlorinated natural rubbers, chlorinated polyolefins, chlorinated butyl rubbers, and mixtures thereof.
9. The process according to claim 8 , wherein the chlorinated, polyalkadiene comprises polychloroprene.
10. The process according to claim 5 , wherein base comprises a guanidine substituted by two aryl groups.
11. The process according to claim 10 , wherein the organic base is diphenylguanidine.
12. The process according to claim 5 , wherein the bis(2,5-dimercapto-1,3,4-thiadiazole) to organic base molar ratio is approximately 50:50.
13. The composition according to claim 1 , wherein the sulphur is present in the composition in a ratio of up to 1:1 by weight with respect to the amount of bis(2,5-dimercapto-1,3,4-thiadiazole).
14. The process according to claim 5 herein the sulphur is present in the mixture, in a ratio of up to 1:1 by weight with resect the amount of bis(2,5-dimercapto-1,3,4-thiadiazole).
15. The composition according to claim 1 , wherein the chlorinated polyalkadiene is chosen from chloroprene rubbers or polychloroprenes, chlorinated natural rubbers, chlorinated polyolefins, chlorinated butyl rubbers, and mixtures thereof.
16. The composition according to claim 15 , herein the chlorinated polyalkadiene comprises polychloroprene.
17. The composition according to claim 1 , wherein the chlorinated polyalkadiene is polychloroprene.
18. The process according to claim 5 , wherein the chlorinated polyalkadiene is polychloroprene.
19. The composition according to claim 1 , wherein
the chlorinated polyalkadiene is polychloroprene, and
the organic base is diphenylguanidine.
20. The method according to claim 5 wherein
the chlorinated polyalkadiene is polychloroprene, and
the organic base is diphenylguanidine.