Propylene-based polymer additives for improved tire tread performance

1. A tire tread composition comprising components, by weight of the composition, within the range from:

5 to 75 wt % of a diene elastomer;

0 to 40 wt % of processing oil;

20 to 80 wt % of filler;

a curative agent; and

5 to 30 wt % of a propylene-ethylene-diene terpolymer containing from 2 to 40 wt % of ethylene and/or C 4 -C 20 α-olefins derived units, from 2 wt % to 20 wt % ethylene, and from 0.5 to 10 wt % of ethylidene norbornene, and having a heat of fusion, as determined by DSC, of 0 J/g, and a melt flow rate (MFR) at 2.16 kg weight at 230° C. of 0.2 to 10 g/10 min.

2. The tire tread composition of claim 1 , wherein the filler is a silica-based filler.

3. The tire tread composition of claim 1 , wherein the filler is a carbon black filler.

4. The tire tread composition of claim 1 , wherein the filler is blend of silica-based filler and a carbon black filler.

5. The tire tread composition of claim 1 , wherein the propylene-ethylene-diene terpolymer contains 60 wt % to 95 wt % propylene.

6. The tire tread composition of claim 1 , wherein the Tg (° C.) of the tire tread composition is from 0 to −60.

7. The tire tread composition of claim 1 , wherein the diene elastomer is a styrenic copolymer, a polybutadiene, natural rubber, a polyisoprene, a butadiene copolymer, an isoprene copolymer or blends thereof.

8. The tire tread composition of claim 1 , wherein the propylene-ethylene-diene terpolymer further comprises 1 to 4 phr sulfur.

9. The tire tread composition of claim 1 , wherein the propylene-ethylene-diene terpolymer has a Tg (° C.) of from 0 to −20.