Rubber composition comprising a specific hydrocarbon resin
A rubber composition based on at least: from 50 to 100 phr of one or more diene elastomers, referred to as very low glass transition temperature (Tg) diene elastomers, having a Tg within a range of from −110° C. to −70° C., selected from butadiene homopolymers, copolymers of butadiene and of a vinylaromatic monomer, having a content of vinylaromatic units of between 0 and 5% by weight, and mixtures thereof a reinforcing filler a crosslinking system; and from 40 to 150 phr of at least one hydrogenated hydrocarbon resin predominantly composed of units derived from C 9 monomers, the resin having a content of aromatic protons of less than 25% and a content of ethylenic protons of less than 1%.
1. A rubber composition based on at least:
from 50 to 100 phr of at least one diene elastomer,
wherein the at least one diene elastomer is a very low glass transition temperature Tg diene elastomer consisting of a copolymer of butadiene and of a vinylaromatic monomer, wherein the copolymer of butadiene and of a vinylaromatic monomer has a Tg within a range of from −110° C. to −70° C. and has a content of vinylaromatic units of between 0 and 5% by weight relative to the total weight of the at least one diene elastomer;
a reinforcing filler;
a crosslinking system; and
from 40 to 150 phr of at least one hydrogenated hydrocarbon resin predominantly composed of units derived from C 9 monomers, the resin having a content of aromatic protons of less than 25% and a content of ethylenic protons of less than 1%.
2. The rubber composition according to claim 1 , wherein the very low glass transition temperature Tg diene elastomer is present at a total content of from 75 to 100 phr.
3. The rubber composition according to claim 1 , wherein the very low glass transition temperature Tg diene elastomer has a Tg within a range of from −100° C. to −80° C.
4. The rubber composition according to claim 1 , wherein the very low glass transition temperature Tg diene elastomer has a Mooney viscosity within a range of from 50 to 80.
5. The rubber composition according to claim 1 , wherein the very low glass transition temperature Tg diene elastomer has a content of 1,2-bonds relative to a diene portion ranging from 8% to 15% by weight.
6. The rubber composition according to claim 5 , wherein at least 70% by weight of the copolymer of butadiene and of a vinylaromatic monomer is functionalized.
7. The rubber composition according to claim 6 , wherein the copolymer of butadiene and of a vinylaromatic monomer is functionalized with an alkoxysilane group, optionally partially or completely hydrolyzed to give silanol, the alkoxysilane group optionally bearing another function capable of interacting with a reinforcing filler, the alkoxysilane group being bonded to the diene elastomer by means of the silicon atom.
8. The rubber composition according to claim 6 , wherein the copolymer of butadiene and of a vinylaromatic monomer is functionalized predominantly in the middle of the chain.
9. The rubber composition according to claim 5 , wherein the copolymer of butadiene and of a vinylaromatic monomer comprises more than 0 and up to 30% by weight, relative to the total weight of the copolymer of butadiene and of a vinylaromatic monomer, of a star-branched copolymer of butadiene and of a vinylaromatic monomer.
10. The rubber composition according to claim 9 , wherein the copolymer of butadiene and of a vinylaromatic monomer comprises between 0 and 20% by weight of a star-branched copolymer of butadiene and of a vinylaromatic monomer.
11. The rubber composition according to claim 1 , wherein the copolymer of butadiene and of a vinylaromatic monomer is present at a content within a range of from 50 to 100 phr.
12. The rubber composition according to claim 11 , wherein the copolymer of butadiene and of a vinylaromatic monomer is present at a content within a range of from 90 to 100 phr.
13. The rubber composition according to claim 1 , wherein a content of the hydrocarbon resin is within a range of from 45 to 120 phr.
14. The rubber composition according to claim 1 , wherein the hydrocarbon resin has a content of aromatic protons of less than 10%.
15. The rubber composition according to claim 1 , wherein the hydrocarbon resin has a content of aromatic protons of less than 5%.
16. The rubber composition according to claim 1 , wherein the hydrocarbon resin has a glass transition temperature Tg of greater than 60° C.
17. The rubber composition according to claim 1 , wherein the hydrocarbon resin has a content of ethylenic protons of less than 0.5%.
18. The rubber composition according to claim 1 , wherein the hydrocarbon resin does not comprise any ethylenic units.
19. The rubber composition according to claim 1 , wherein the hydrocarbon resin has an Mn of greater than 600 g/mol.
20. The rubber composition according to claim 1 , wherein the hydrocarbon resin has a polydispersity index of less than 2.
21. The rubber composition according to claim 1 , wherein the reinforcing filler is selected from the group consisting of silicas, carbon blacks, and mixtures thereof.
22. The rubber composition according to claim 1 , wherein a content of reinforcing filler is within a range of from 5 to 200 phr.
23. The rubber composition according to claim 1 , wherein a predominant reinforcing filler is silica at a content within a range of from 40 to 150 phr.
24. The rubber composition according to claim 23 further comprising a minority amount of carbon black at a content within a range of from 0.1 to 10 phr.
25. A tire comprising the rubber composition according to claim 1 .
26. The tire according to claim 25 , wherein the rubber composition constitutes all or part of a tread of the tire.