Rubber composition and tire
The present invention is directed to a rubber composition comprising 10 phr to 100 phr of at least one partially saturated elastomer comprising repeat units, wherein at most 15% of all repeat units of the elastomer comprise a double bond; 0 phr to 90 phr of at least one diene based elastomer; 40 phr to 200 phr of at least one filler; and at least 5 phr of aluminum hydroxide.
1 . A sulfur vulcanizable rubber composition comprising:
80 phr to 95 phr of at least one partially saturated elastomer comprising repeat units, wherein at least 2% and at most 15% of all repeat units of the partially saturated elastomer comprise a double bond, wherein the at least one partially saturated elastomer is a diene-based elastomer;
5 phr to 20 phr of at least one polybutadiene having a glass transition temperature within a range of −90° C. to −115° C.;
40 phr to 200 phr of filler comprising silica and at least 30 phr of aluminum hydroxide.
2 . The rubber composition according to claim 1 wherein at most 8% of the repeat units have a double bond.
3 . The rubber composition according to claim 1 wherein at least 4% of the repeat units have a double bond.
4 . The rubber composition according to claim 1 wherein said filler comprises one or more of: (i) from 35 phr to 190 phr of silica, (ii) silica and carbon black, wherein silica is the predominant filler material, (iii) silica with a BET surface area within a range of 150 m 2 /g to 250 m 2 /g, and (iv) less than 10 phr carbon black.
5 . The rubber composition according to claim 1 wherein the aluminum hydroxide has one or more of: (i) a D50 particle diameter within a range of 0.2 μm and 30 μm, and (ii) a BET surface area within a range of 1 m 2 /g to 20 m 2 /g.
6 . The rubber composition according to claim 1 comprising from 30 phr to 80 phr of the aluminum hydroxide.
7 . The rubber composition according to claim 1 wherein the partially saturated elastomer comprises repeat units formed by residues of monomers selected from ethylene, propylene, butadiene, isoprene, and styrene.
8 . The rubber composition according to claim 1 wherein the partially saturated elastomer is a hydrogenated styrene butadiene rubber.
9 . The rubber composition according to claim 1 further comprising from 3 phr to 20 phr of a polyoctenamer.
10 . The rubber composition according to claim 9 wherein the polyoctenamer has one or more of:
a glass transition temperature within a range of −50° C. to −80° C.;
a molecular weight Mw within a range of 80,000 to 100,000 g/mol, determined by GPC;
a melting point within a range of 45° C. to 55° C., measured by DSC in a second heating; and
between 65% and 85% of trans double bonds.
11 . The rubber composition according to claim 10 wherein the rubber composition comprises from 80 phr to 95 phr of the partially saturated elastomer and from 5 phr to 20 phr of polyisoprene.
12 . The rubber composition according to claim 1 , wherein the partially saturated elastomer has one or more of:
a glass transition temperature within a range of −20° C. to −60° C.; and
a molecular weight Mw within a range of 200,000 g/mol to 500,000 g/mol.
13 . The rubber composition according to claim 1 , wherein the partially saturated elastomer is a solution-polymerized styrene butadiene rubber having one or more of:
(i) less than 5% of nonhydrogenated vinyl groups, based on the total number of vinyl groups of the hydrogenated styrene butadiene rubber;
(ii) less than 20% of nonhydrogenated double bonds in cis-1,4 and trans-1,4 butadiene repeat units, based on the total number of cis-1,4 and trans-1,4 butadiene repeat units;
(iii) from 80% to 99% of hydrogenated double bonds;
(iv) a bound styrene content ranging from 5% to 40% and a butadiene content ranging from 50% to 95%, by weight; and
(v) a molecular weight Mw within a range of 200,000 g/mol to 500,000 g/mol.
14 . The rubber composition according to claim 1 wherein the rubber composition comprises:
from 5 phr to 50 phr of at least one plasticizer chosen from one or more of at least one oil and at least one resin.
15 . The rubber composition according to claim 1 wherein the rubber composition comprises at least 3 phr of at least one mercapto silane.
16 . The rubber composition according to claim 1 wherein the rubber composition further comprises a resin selected from one or more of DCPD resins, CPD resins, terpene resins, C5 resins, C9 resins, coumarone indene resin, styrene-alphamethylstyrene or combinations of those.
17 . The rubber composition according to claim 1 further comprising 0.3 phr to 3 phr of a vulcanization accelerator selected from one or more of dithiocarbamate accelerators and thiuram accelerators.
18 . A tire comprising the rubber composition of claim 1 .