Tread with ultra efficient vulcanization system
View Patent ↗Tire treads having improved traction properties while surprisingly still maintaining good material cohesion properties, the tire treads comprising a rubber composition based upon a highly unsaturated diene elastomer and between 95 phr and 160 phr of an inorganic reinforcing filler. The composition may further include between 60 phr and 130 phr of a plasticizing system made up of a plasticizing resin having a Tg of at least 25° C. and a plasticizing liquid. The rubber composition is cured with an ultra-efficient sulfur curing system having a sulfur to accelerator weight ratio adjusted between 0.02 and 0.2 to provide the rubber composition with an MA300/G* ratio of greater than 1.7, wherein the elongation modulus MA300 at 300% is measured at 23° C. and the shear modulus G* is measured at 60° C.
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):
a highly unsaturated diene elastomer;
between 95 phr and 160 phr of an inorganic reinforcing filler;
between 60 phr and 130 phr of a plasticizing system comprising a plasticizing resin having a Tg of at least 25° C. and a plasticizing liquid;
an ultra-efficient sulfur curing system having a sulfur to accelerator weight ratio adjusted between 0.02 and 0.2 to provide the rubber composition with an MA300/G* ratio of greater than 1.7, wherein the elongation modulus MA300 at 300% is measured at 23° C. and the shear modulus G* is measured at 60° C.
2. The tread of claim 1 , wherein the rubber composition has a glass transition temperature of between −35° C. and 0° C.
3. The tread of claim 1 , wherein the sulfur to accelerator weight ratio is between 0.05 and 0.15.
4. The tread of claim 1 , wherein the MA300/G* ratio is between 1.7 and 3.
5. The tread of claim 1 , wherein the shear modulus G* at 60° C. is between 0.4 MPa and 1.4 MPa.
6. The tread of claim 1 , wherein the shear modulus G* at 60° C. is between 0.5 MPa and 1 MPa.
7. The tread of claim 1 , wherein the inorganic reinforcing filler is a highly dispersible silica.
8. The tread of claim 1 , wherein a ratio of the plasticizing resin to the plasticizing liquid is between 4:1 and 1:4.
9. The tread of claim 1 , wherein a ratio of the plasticizing resin to the plasticizing liquid is between 2:1 and 1:2.
10. The tread of claim 1 , wherein the plasticizing resin has a glass transition temperature of between 40° C. and 85° C.
11. The tread of claim 10 , wherein the plasticizing resin is a polylimonene resin.
12. The tread of claim 1 , wherein the plasticizing liquid is selected from sunflower oil, soybean oil, safflower oil, corn oil, linseed oil, cotton seed oil or combinations thereof.
13. The tread of claim 12 , wherein the plasticizing liquid has an oleic content of at least 80 wt. %.
14. The tread of claim 1 , wherein the plasticizing system comprises between 5 phr and 70 phr of the plasticizing liquid.
15. The tread of claim 1 , wherein the plasticizing system comprises between 5 phr and 125 phr of the plasticizing resin.