Resin-extended elastomer
A resin-extended elastomer comprises an elastomer which is a synthetic diene elastomer with a number-average molar mass of greater than or equal to 200,000 g/mol and a resin which is a plasticizing hydrocarbon-based resin. A process for obtaining such a resin-extended elastomer and compositions, semi-finished products for tires and tires containing same are also disclosed.
1. A resin-extended elastomer, the elastomer of which is a synthetic diene elastomer obtained by solution polymerization with a number-average molar mass of greater than or equal to 200,000 g/mol and the resin of which is a plasticizing hydrocarbon-based resin having a number-average molar mass of between 400 and 2000 g/mol, wherein the synthetic diene elastomer has a 1,2-vinyl butadiene monomer content of 5% to 30% by weight relative to a total weight of a polybutadiene part of the synthetic diene elastomer.
2. The resin-extended elastomer according to claim 1 , wherein the number-average molar mass of the synthetic diene elastomer is in a range extending from 250,000 g/mol to 450,000 g/mol.
3. The resin-extended elastomer according to claim 1 , wherein the plasticizing hydrocarbon-based resin is selected from the group consisting of aliphatic resins, aromatic resins and mixtures thereof.
4. The resin-extended elastomer according to claim 3 , wherein the plasticizing hydrocarbon-based resin is selected from the group consisting of cyclopentadiene homopolymer or copolymer resins, dicyclopentadiene homopolymer or copolymer resins, terpene homopolymer or copolymer resins, C5 fraction homopolymer or copolymer resins, C9 fraction homopolymer or copolymer resins, mixtures of C5 fraction homopolymer or copolymer resins and of C9 fraction homopolymer or copolymer resins, α-methylstyrene homopolymer or copolymer resins, and mixtures thereof.
5. The resin-extended elastomer according to claim 1 , wherein the content of plasticizing hydrocarbon-based resin is in a range extending from 5 to 100 phr.
6. The resin-extended elastomer according to claim 1 obtained by mixing the synthetic diene elastomer in solution in an organic solvent and the plasticizing hydrocarbon-based resin in the liquid state.
7. A composition based on at least one resin-extended elastomer according to claim 1 and on at least one reinforcing filler and further comprising at least one chemical crosslinking system.
8. A semi-finished product for a tire comprising at least one resin-extended elastomer according to claim 1 .
9. A semi-finished product for a tire comprising at least one composition according to claim 7 .
10. A tire comprising at least one resin-extended elastomer according to claim 1 .
11. A tire comprising at least one composition according to claim 7 .
12. A process for obtaining a resin-extended elastomer, the process comprising at least (a) one step of placing at least one synthetic diene elastomer in solution in an organic solvent in contact with at least one plasticizing hydrocarbon-based resin, the synthetic diene elastomer having a number-average molar mass of greater than or equal to 200,000 g/mol and a 1,2-vinyl butadiene monomer content of 5% to 30% by weight relative to the total weight of a polybutadiene part of the synthetic diene elastomer, and the plasticizing hydrocarbon-based resin having a number-average molar mass of between 400 and 2000 g/mol;
(b) one mixing step of mixing to obtain a homogenous solution of synthetic diene elastomer and of plasticizing hydrocarbon-based resin;
(c) one steam stripping step of steam stripping to recover a gaseous fraction enriched in organic solvent and an aqueous dispersion of particles of synthetic diene elastomer and of plasticizing hydrocarbon-based resin; and
(d) one step of recovering the resin-extended elastomer form the aqueous dispersion of particles of synthetic diene elastomer and of plasticizing hydrocarbon-based resin.
13. The process for obtaining a resin-extended elastomer according to claim 12 , wherein the synthetic diene elastomer of step (a) is obtained either by dissolution of the synthetic diene elastomer in the organic solvent or by solution polymerization in the organic solvent of corresponding monomers of the synthetic diene elastomer.
14. The process for obtaining a resin-extended elastomer according to claim 12 , wherein, during the placing in contact in step (a), the plasticizing hydrocarbon-based resin is in the liquid state.
15. The process for obtaining a resin-extended elastomer according to claim 12 , wherein the number-average molar mass of the synthetic diene elastomer is a less than or equal to 500,000 g/mol.
16. The process for obtaining a resin-extended elastomer according to claim 12 , wherein the synthetic diene elastomer has a glass transition temperature of less than or equal to−60° C.