High-performance tyre
A tyre for wheels of vehicles, in particular motor vehicles, is described. The tyre has a tread with at least one copolymer selected from iso-styrene: diene-terminated copolymers. The tread has less sensitivity to the effects of temperature, with less weakness, better consistency of performances, and improved characteristics in terms of grip and/or resistance to laceration.
1. A tire for vehicle wheels comprising:
a carcass structure; and
a tread band applied in radially outer position with respect to said carcass structure;
wherein said tread band comprises a crosslinked elastomeric material obtained by crosslinking a crosslinkable elastomeric composition, wherein said elastomeric composition comprises at least a iso-styrene:diene-terminated copolymer.
2. The tire for vehicle wheels according to claim 1 , wherein said copolymer comprises styrene and/or substituted styrene.
3. The tire for vehicle wheels according to claim 2 , wherein said substituted styrene is represented by formula S-R, wherein S is a styrene residue and R can be a linear or branched alkyl radical containing from 1 to 20 carbon atoms, a linear or branched alkenyl substituent containing from 2 to 20 carbon atoms, an aryl, even condensed, or alkylaryl substituent containing from 6 to 30 carbon atoms, a halogen or a radical containing one or more silicon atoms.
4. The tire for vehicle wheels according to claim 2 , wherein said substituted styrene is selected from the group consisting of p-methylstyrene, o-methylstyrene, p-isopropylstyrene, p-terbutylstyrene, alpha and beta vinylnaphthalene, p-fluorostyrene, p-chlorostyrene, and p-trimethylsilylstyrene.
5. The tire for vehicle wheels according to claim 1 , wherein said copolymer has a content of styrene, substituted styrene, or mixture thereof, equal to or higher than 98% by weight with respect to the total weight of copolymer.
6. The tire for vehicle wheels according to claim 5 , wherein said copolymer has a content of styrene, substituted styrene, or mixture thereof, ranging from 99.5% to 99.99% by weight with respect to the total weight of copolymer.
7. The tire for vehicle wheels according to claim 1 , wherein the dienic monomer employed to realize the terminal polymeric block of said copolymer is selected from the group comprising isolated or conjugated dienic monomers.
8. The tire for vehicle wheels according to claim 7 , wherein said dienic monomer is selected from the group consisting of isoprene, 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, cyclopentadiene, 1-vinyl-cyclopentene, 1-vinyl-cyclopentene, 2-vinyl-cyclohexene, 4-vinyl-cyclohexene, and mixtures thereof.
9. The tire for vehicle wheels according to claim 8 , wherein said dienic monomer is selected from the group consisting of isoprene, 1,4-hexadiene, cyclopentadiene, and mixtures thereof.
10. The tire Tyre for vehicle wheels according to claim 1 , wherein said terminal polymeric block consists of a sequence of one or more dienic monomers comprising a number of concatenated dienic units ranging from 3 to 100.
11. The tire Tyre for vehicle wheels according to claim 1 , wherein said terminal polymeric block represents less than 2% by weight with respect to the total weight of copolymer.
12. The tire Tyre for vehicle wheels according to claim 1 , wherein said copolymer has an inflection point Tg value measured with DSC at 10° C./min ranging from 40° C. to 110° C.
13. The tire Tyre for vehicle wheels according to claim 1 , wherein said copolymer has a molecular weight higher than or equal to 20,000 Da.
14. The tire for vehicle wheels according to claim 1 , wherein said copolymer has a molecular weight lower than or equal to 1,500,000 Da.
15. The tire for vehicle wheels according to claim 1 , wherein said elastomeric composition comprises an amount of said copolymer higher than 1 phr.
16. The tire for vehicle wheels according to claim 15 , wherein said elastomeric composition comprises an amount of said copolymer ranging from 2.5 and 10 phr.
17. The tire for vehicle wheels according to claim 1 , wherein said elastomeric composition comprises an amount of said copolymer lower than 20 phr.
18. The tire for vehicle wheels according to claim 1 , wherein said copolymer has a content of styrene, substituted styrene, or mixture thereof, equal to or higher than 99% by weight with respect to the total weight of copolymer.
19. The tire for vehicle wheels according to claim 1 , wherein said terminal polymeric block represents less than 1% by weight with respect to the total weight of copolymer.
20. The tire for vehicle wheels according to claim 1 , wherein said copolymer has a molecular weight higher than or equal to 50,000 Da.
21. The tire for vehicle wheels according to claim 1 , wherein said copolymer has a molecular weight higher than or equal to 100,000 Da.
22. The tire for vehicle wheels according to claim 1 , wherein said copolymer has a molecular weight higher than or equal to 200,000 Da.
23. The tire for vehicle wheels according to claim 1 , wherein said copolymer has a molecular weight lower than or equal to 1,250,000 Da.
24. The tire for vehicle wheels according to claim 1 , wherein said copolymer has a molecular weight lower than or equal to 1,000,000 Da.
25. The tire for vehicle wheels according to claim 1 , wherein said copolymer has a molecular weight lower than or equal to 900,000 Da.
26. The tire for vehicle wheels according to claim 1 , wherein said elastomeric composition comprises an amount of said copolymer higher than 2 phr.
27. The tire for vehicle wheels according to claim 1 , wherein said elastomeric composition comprises an amount of said copolymer lower than 15 phr.