TIRE TREAD
Treads and tires having such treads having improved characteristics breaking the compromise between Wear and wet braking, such treads manufactured from a rubber composition that may include greater than 90 phr of an elastomer component selected from styrene-butadiene rubber (SBR), a polybutadiene or combinations thereof having, a glass transition temperature of between −100° C. and less than −50° C. and a plasticizing system. The plasticizing system may include, for example, between 5 phr and 120 phr of a plasticizing resin having a Tg of at least 25° C. and between 0 phr and 60 phr of a plasticizing liquid. Particular embodiments may include the elastomer component having a Tg of between −90° C. and −60° C. and/or may further have the elastomer component included in an amount of at least 95 phr.
1 . A tread for a tire, the tread comprising a rubber composition that is based upon a cross-linkable elastomer composition, the cross-linkable elastomer composition comprising, per 100 parts by weight of rubber (phr):
greater than 90 phr of an elastomer component selected from a styrene-butadiene rubber, a polybutadiene rubber or combinations thereof having a glass transition temperature of between −100° C. and less than −50° C.;
between 0 phr and 9 phr of an additional highly unsaturated diene elastomer;
a plasticizing system comprising between 5 phr and 120 phr of a plasticizing resin having a Tg of at least 25° C. and between 0 phr and 60 phr of a plasticizing liquid;
a reinforcing filler; and
a curing system.
2 . The tread of claim 1 , wherein the plasticizing system comprises between 10 phr and 55 phr of the plasticizing liquid.
3 . The tread of claim 1 , wherein the plasticizing system comprises between 55 phr and 120 phr of the plasticizing resin.
4 . The tread of claim 1 , wherein the cross-linkable rubber composition comprises between 0 phr and 5 phr of the additional highly unsaturated diene elastomer.
5 . The tread of claim 1 , wherein the cross-linkable rubber composition comprises 0 phr of the additional highly unsaturated diene elastomer.
6 . The tread of claim 1 , wherein the glass transition temperature of the elastomer component is between −100° C. and −55° C.
7 . The tread of claim 1 , wherein the glass transition temperature of the elastomer component is between −90° C. and −60° C.
8 . The tread of claim 1 , wherein a glass transition temperature of the rubber composition is between −30° C. and −10° C.
9 . The tread of claim 1 , wherein the shear modulus G* of the rubber composition is between 0.6 MPa and 1.1 MPa.
10 . The tread of claim 1 , wherein the elastomer component, the additional highly unsaturated diene rubber or combinations thereof are functionalized with an active moiety.
11 . The tread of claim 10 , wherein the elastomer component includes chain ends having a silanol functional group attached as the active moiety.
12 . The tread of claim 1 , wherein the reinforcing filler is silica, the rubber composition comprising between 90 phr and 130 phr of the silica.
13 . The tread of claim 1 , wherein the plasticizing resin has a glass transition temperature of between 40° C. and 85° C.
14 . The tread of claim 11 , wherein the plasticizing resin is a polylimonene resin.
15 . The tread of claim 1 , wherein the rubber composition comprises between 20 phr and 70 phr of the plasticizing resin.
16 . The tread of claim 1 , wherein the plasticizing liquid is a selected from sunflower oil, soybean oil, safflower oil, corn oil, linseed oil, cotton seed oil or combinations thereof.
17 . The tread of claim 15 , wherein the plasticizing liquid has an oleic content of at least 80 wt. %.
18 . The tread of claim 1 , wherein the rubber composition comprises between 10 phr and 50 phr of the plasticizing liquid.
19 . The tread of claim 1 , wherein the rubber composition has a glass transition temperature of between −28° C. and −14° C.
20 . The tread of claim 1 , wherein the rubber composition has a shear modulus G* measured at 60° C. of between 0.5 MPa and 1.5 MPa.
21 . The tread of claim 1 , wherein the elastomer component is 100 phr of the styrene-butadiene rubber.