Diene elastomers with cyclic vinyl units and processes for obtaining same
The present invention relates to a linear or branched diene elastomer having cyclic vinyl units. A linear diene elastomer according to the invention results from at least one conjugated diene and it comprises cyclic vinyl units in a mass content of greater than or equal to 15% while having a number-average molecular weight falling within a range of from 10,000 to 300,000 g/mol. The invention also relates to a process for the production of such a linear or branched diene elastomer including cyclic vinyl units in the above-stated content and having a number-average molecular weight ranging from 10,000 to 300,000 g/mol, such that said process includes the continuous reaction of at least one conjugated diene monomer in an inert aliphatic or alicyclic hydrocarbon solvent with a catalytic system comprising an organolithium initiator, a polar agent having two or more heteroatoms and an alkali metal salt of an aliphatic or alicyclic alcohol, where: (i) the (polar agent:initiator) molar ratio is greater than or equal to 3. (ii) the (salt:initiator) molar ratio falls within a range of from 0.01 to 2, and (iii) the (salt:polar agent) molar ratio falls within a range of from 0.0001 to 0.5.
1. A process for the production of a linear or branched diene elastomer resulting from at least one conjugated diene, said elastomer comprising cyclic vinyl units in a mass content of greater than or equal to 15% and, prior to optional branching, having a number-average molecular weight falling within a range of from 10,000 to 300,000 g/mol, said process comprising the anionic polymerization of one or more monomers comprising at least one conjugated diene monomer, by a continuous reaction, in an inert aliphatic or alicyclic hydrocarbon solvent, of said monomer or monomers with a catalytic system comprising an organolithium initiator, a polar agent comprising two or more heteroatoms, and an alkali metal salt of an aliphatic or alicyclic alcohol, such that said system simultaneously satisfies the following three conditions:
(i)the (polar agent:initiator) molar ratio is greater than or equal to 3,
(ii) the (salt:initiator) molar ratio falls within a range of from 0.01 to 2, and
(iii) the (salt:polar agent) molar ratio falls within a range of from 0.001 to 0.5.
2. A process for the production of a linear or branched diene elastomer according to claim 1 , wherein the (polar agent:initiator) molar ratio is greater than or equal to 5.
3. A process for the production of a linear or branched diene elastomer according to claim 2 , wherein the (polar agent:initiator) molar ratio is greater than or equal to 10.
4. A process for the production of a linear or branched diene elastomer according to claim 3 , wherein the (polar agent:initiator) molar ratio is greater than or equal to 15.
5. A process for the production of a linear or branched diene elastomer according to claim 1 , wherein said (salt:polar agent) molar ratio falls within a range of from 0.001 to 0.1.
6. A process for the production of a linear or branched diene elastomer according to claim 1 , wherein said (salt:initiator) molar ratio falls within a range of from 0.01 to 0.6.
7. A process for the production of a linear or branched diene elastomer according to claim 6 , wherein said (salt:initiator) molar ratio falls within a range of from 0.01 to 0.2.
8. A process for the production of a linear or branched diene elastomer according to claim 7 , wherein said (salt:initiator) molar ratio falls within a range of from 0.3 to 0.6.
9. A process for the production of a linear or branched diene elastomer according to claim 1 , wherein said salt is a sodium salt of an aliphatic alcohol having from 3 to 12 carbon atoms.
10. A process for the production of a branched diene elastomer according to claim 1 , which further comprises reacting the product of said polymerization with a coupling or starring agent in order to obtain said branched diene elastomer.
11. A process for the production of a linear or branched diene elastomer according to claim 9 , wherein said salt is sodium tert. amylate.
12. A process for the production of a linear or branched diene elastomer resulting from at least one conjugated diene, said elastomer comprising cyclic vinyl units in a mass content of greater than or equal to 15% and, prior to optional branching, having a number-average molecular weight falling within a range of from 10,000 to 60,000 g/mol, said process comprising the anionic polymerization of one or more monomers comprising at least one conjugated diene monomer, by a discontinuous reaction, in an inert aliphatic or alicyclic hydrocarbon solvent, of said monomer or monomers with a catalytic system comprising an organolithium initiator and a polar agent comprising two or more heteroatoms, the (polar agent:initiator) molar ratio being greater than 8,
wherein said polar agent is tetramethylethylenediamine.
13. A process for the production of a branched diene elastomer according to claim 12 , which further comprises reacting the product of said polymerization with a coupling or starring agent in order to obtain said branched diene elastomer.
14. A catalytic system usable for producing, by continuous anionic polymerization of one or more conjugated dienes in an inert aliphatic or alicyclic hydrocarbon solvent, a linear diene elastomer resulting from at least one conjugated diene, wherein said diene elastomer comprises cyclic vinyl units in a mass content of greater than or equal to 15% and having a number-average molecular weight falling within a range of from 50,000 to 300,000 g/mol, wherein said system comprises an organolithium initiator, a polar agent comprising two or more heteroatoms and an alkali metal salt of an aliphatic or alicyclic alcohol, said system simultaneously satisfying the following three conditions:
(iv) the (polar agent:initiator) molar ratio is greater than or equal to 10,
(v) the (salt:initiator) molar ratio falls within a range of from 0.01 to 2, and
(vi) the (salt:polar agent) molar ratio falls within a range of from 0.001 to 0.5,
wherein said polar agent belongs to the group consisting of diamines and diethers.
15. A catalytic system according to claim 14 , wherein said salt is a sodium salt of an aliphatic alcohol having from 3 to 12 carbon atoms.
16. A catalytic system according to claim 15 , wherein said salt is sodium tert. amylate.
17. A catalytic system according to claim 14 , wherein said (salt:initiator) molar ratio falls within a range of from 0.01 to 0.2.
18. A catalytic system according to claim 14 , wherein said (salt:initiator) molar ratio falls within a range of from 0.3 to 0.6.
19. A catalytic system usable for producing, by continuous anionic polymerization of one or more conjugated dienes in an inert aliphatic or alicyclic hydrocarbon solvent, a linear diene elastomer resulting from at least one conjugated diene, wherein said diene elastomer comprises cyclic vinyl units in a mass content of greater than or equal to 15% and having a number-average molecular weight falling within a range of from 50,000 to 300,000 g/mol,
wherein said system comprises an organolithium initiator, a polar agent comprising two or more heteroatoms and an alkali metal salt of an aliphatic or alicyclic alcohol, said system simultaneously satisfying the following three conditions:
(iv) the (polar agent:initiator) molar ratio is greater than or equal to 10,
(v)the (salt:initiator) molar ratio falls within a range of from 0.01 to 0.2 or from 0.3 to 2, and
(vi) the (salt:polar agent) molar ratio falls within a range of from 0.001 to 0.1.
20. A catalytic system according to claim 19 , wherein said (polar agent:initiator) molar ratio is greater than or equal to 15.
21. A catalytic system according to claim 19 , wherein said (salt:initiator) molar ratio falls within a range of from 0.01 to 0.2.
22. A catalytic system according to claim 19 , wherein said (salt:initiator) molar ratio falls within a range of from 0.3 to 0.6.
23. A catalytic system according to claim 19 , wherein said polar agent belongs to the group consisting of diamines and diethers.
24. A catalytic system usable for producing, by continuous or discontinuous anionic polymerization of one or more conjugated dienes in an inert aliphatic or alicyclic hydrocarbon solvent, a linear diene elastomer comprising cyclic vinyl units in a mass content of greater than or equal to 15% and having a number-average molecular weight falling within the range of from 10,000 to 60,000 g/mol, said system comprising an organolithium initiator and a polar agent comprising two or more heteroatoms, wherein the (polar agent:iitiator) molar ratio is greater than or equal to 10,
wherein said polar agent is tetramethylethylenediamine.
25. A catalytic system usable for producing, by continuous anionic polymerization of one or more conjugated dienes in an inert aliphatic or alicyclic hydrocarbon solvent, a linear diene elastomerresulting from at least one conjugated diene, wherein said diene elastomer comprises cyclic vinyl units in a mass content of greater than or equal to 15% and having a number-average molecular weight falling within a range of from 50,000 to 300,000 g/mol,
wherein said system comprises an organolithium initiator, a polar agent comprising two or more heteroatoms and an alkali metal salt of an aliphatic or alicyclic alcohol, said system simultaneously satisfying the following three conditions:
(iv) the polar agent:initiator molar ratio is equal to or greater than 14.1,
(v) the (salt:initiator) molar ratio falls within a range of from 0.01 to 2, and
(vi) the (salt:polar agent) molar ratio falls within a range of from 0.001 to 0.5.