Rubber composition for tire tread and pneumatic tire using the same

Patent metadata

Field	Value
Publication number	US-12558920-B2
Application number	US-202318128437-A
Country	US
Kind code	B2
Filing date	Mar 30, 2023
Priority date	Apr 15, 2022
Publication date	Feb 24, 2026
Grant date	Feb 24, 2026

Abstract

A rubber composition for a tire tread is disclosed, which provides a tire excellent in wet grip performance at low temperatures and wet grip performance at high temperatures. The rubber composition for a tire tread includes, per 100 parts by mass of diene-based rubbers including (a) 25 to 65 parts by mass of a modified styrene butadiene rubber having a glass transition point of −30° C. or more and (b) 25 to 65 parts by mass of a modified styrene butadiene rubber having a glass transition point of −50° C. or less: 80 to 140 parts by mass of silica; 15 to 50 parts by mass of a thermoplastic resin having a softening point of 40° C. or more; and 5 to 15 parts by mass of an oil.

First claim

What is claimed is:

1 . A rubber composition for a tire tread, comprising, per 100 parts by mass of diene-based rubbers including
(a) 25 to 65 parts by mass of a modified styrene butadiene rubber having a glass transition point of −30° C. or more and (b) 25 to 65 parts by mass of a modified styrene butadiene rubber having a glass transition point of −50° C. or less: 80 to 140 parts by mass of silica; 15 to 50 parts by mass of a thermoplastic resin having a softening point of 40° C. or more; and 5 to 15 parts by mass of an oil.

2 . The rubber composition for a tire tread according to claim 1 , wherein the difference in styrene content between the modified styrene butadiene rubber (a) and the modified styrene butadiene rubber (b) is 5 to 30 mass %.

3 . The rubber composition for a tire tread according to claim 1 , wherein the thermoplastic resin is a styrene-based resin or a terpene-based resin.

4 . The rubber composition for a tire tread according to claim 2 , wherein the thermoplastic resin is a styrene-based resin or a terpene-based resin.

5 . The rubber composition for a tire tread according to claim 1 , having a storage modulus of 150 MPa or less as measured at −5° C., a frequency of 10 Hz, a dynamic strain of 0.2%, and a static strain of 10%.

6 . The rubber composition for a tire tread according to claim 2 , having a storage modulus of 150 MPa or less as measured at −5° C., a frequency of 10 Hz, a dynamic strain of 0.2%, and a static strain of 10%.

7 . The rubber composition for a tire tread according to claim 1 , wherein the difference between the following storage modulus (A) and storage modulus (B) is 20 MPa or less:
Storage modulus (A): measured at 25° C., a frequency of 10 Hz, a dynamic strain of 0.1%, and a static strain of 10%, Storage modulus (B): measured at 25° C., a frequency of 10 Hz, a dynamic strain of 5%, and a static strain of 10%.

8 . The rubber composition for a tire tread according to claim 2 , wherein the difference between the following storage modulus (A) and storage modulus (B) is 20 MPa or less:
Storage modulus (A): measured at 25° C., a frequency of 10 Hz, a dynamic strain of 0.1%, and a static strain of 10%, Storage modulus (B): measured at 25° C., a frequency of 10 Hz, a dynamic strain of 5%, and a static strain of 10%.

9 . The rubber composition for a tire tread according to claim 1 , comprising 5 to 20 parts by mass of a protected mercaptosilane per 100 parts by mass of silica.

10 . The rubber composition for a tire tread according to claim 2 , comprising 5 to 20 parts by mass of a protected mercaptosilane per 100 parts by mass of silica.

11 . A pneumatic tire using the rubber composition according to claim 1 in a tread thereof.

12 . A pneumatic tire using the rubber composition according to claim 2 in a tread thereof.

Assignees

• Toyo Tire Corp

Inventors

• Kimura Takuya

Classifications

• C08L91/00

  Compositions of oils, fats or waxes; Compositions of derivatives thereof · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C08L25/08

  Copolymers of styrene (C08L29/08, C08L35/06, C08L55/02 take precedence) · CPC title

• C08K5/548

  containing sulfur {(C08K5/5477 takes precedence)} · CPC title

• C08L2205/035

  containing four or more polymers in a blend · CPC title