# US 4,396,743 A · Rubber composition for tires containing block copolymer having vinyl bonds

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- Number: US 4,396,743 A
- Document ID: US4396743A
- Status: Granted
- Kind: A
- Application number: 06/334,049
- Filed: 1981-12-23
- Granted: 1983-08-02
- Earliest claimed: 1980-12-26
- Assignees: Bridgestone Tire Company Limited
- Inventors: Tatsuo Fujimaki; Tomoharu Yamada; Seisuke Tomita
- Web page: https://patentgrep.com/patent/US4396743A

## CPC

- C08L 9/00: Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
- B60C 1/0016: {Compositions of the tread}
- C08L 53/02: of vinyl-aromatic monomers and conjugated dienes
- Y10S 152/905: Tread composition
- Y10S 525/914: Polymer from conjugated diene hydrocarbon or halohydrocarbons having more than 50 per cent 1,2-microstructure
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A rubber composition adapted to be used as a tread rubber is disclosed. The rubber composition has remarkably improved resistance against heat generation, breakage resistance, wear resistance, wet skid resistance and low-temperature brittleness, and consists mainly of a rubber blend consisting of 20-95 parts by weight of a styrene-butadiene block copolymer having a specifically limited structure and 80-5 parts by weight of a diene rubber.

## Claims

### Claim 1

A rubber composition for tires, consisting mainly of a rubber blend consisting of 20-95 parts by weight of a styrene-butadiene block copolymer and 80-5 parts by weight of a diene rubber; said styrene-butadiene block copolymer being a copolymer obtained by block copolymerizing styrene with 1,3-butadiene, consisting of a random copolymer block (A) and a random copolymer block (B), the fraction of the copolymer block (A) being 10-90% by weight, and having a total bonded styrene content of 10-40% by weight and a total vinyl bond content in the total bonded butadiene unit of 25-70% by weight; said random copolymer block (A) having a bonded styrene content of 20-50% by weight and a vinyl bond content in the butadiene unit of 40-75% by weight; and said random copolymer block (B) having a bonded styrene content of not higher than 10% by weight and a vinyl bond content in the butadiene unit of 20-50% by weight.

### Claim 2 (depends on 1)

A rubber composition for tires according to claim 1, wherein said rubber blend consists of 20-80 parts by weight of the styrene-butadiene block copolymer and 80-20 parts by weight of a diene rubber having a glass transition temperature of not higher than -50.degree. C.