	US 12,325,797 B2
	Tire tread rubber composition and related methods
Jamie L. Whyte, Kent, OH (US); Anthony M. Unger, New Albany, OH (US); Kenny L. Howman, Ashland, OH (US); and Benjamin C. Galizio, Munroe Falls, OH (US)
Assigned to Bridgestone Americas Tire Operations, LLC, Nashville, TN (US)
Appl. No. 17/614,960
Filed by Bridgestone Americas Tire Operations, LLC, Nashville, TN (US)
PCT Filed May 28, 2020, PCT No. PCT/US2020/034930 § 371(c)(1), (2) Date Nov. 29, 2021, PCT Pub. No. WO2020/243308, PCT Pub. Date Dec. 3, 2020.
Claims priority of provisional application 62/854,095, filed on May 29, 2019.
Prior Publication US 2022/0235208 A1, Jul. 28, 2022
Int. Cl. C08L 9/06 (2006.01)

CPC C08L 9/06 (2013.01) [C08L 2205/035 (2013.01)]

20 Claims

1. A tire tread rubber composition made of ingredients comprising:

a. 100 parts of an elastomer component comprising:

i. 60-70 parts of polybutadiene having a cis bond content of at least 95% and a Tg of less than −101° C.,

ii. 30-40 parts of at least one styrene-butadiene rubber having a Tg of at least −20° C.,

iii. optionally up to 5 parts of natural rubber, polyisoprene, or a combination thereof;

b. at least one reinforcing silica filler in an amount of 81-120 phr having a surface area of about 150 to about 300 m²/g;

c. no more than 10 phr of carbon black filler;

d. 25-40 phr of at least one hydrocarbon resin having a Tg of about 30 to about 50° C.;

e. 5-30 phr of liquid plasticizer; and

f. a cure package,

wherein the total amount of (d) and (e) is 30-59 phr, and

wherein the rubber composition has a value for tan δ at 60° C. of 0.21 to 0.28.