# US 9,518,173 B2 · Tire rubber composition and pneumatic tire

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- Number: US 9,518,173 B2
- Document ID: US9518173B2
- Status: Granted
- Kind: B2
- Application number: 13/949,301
- Filed: 2013-07-24
- Published: 2014-01-30
- Granted: 2016-12-13
- Earliest claimed: 2012-07-25
- Assignees: Sumitomo Rubber Industries, Ltd.
- Applicants: Sumitomo Rubber Industries, Ltd.
- Inventors: Toshio Tada
- Web page: https://patentgrep.com/patent/US9518173B2

## CPC

- C08L 9/06: Copolymers with styrene
- B60C 1/0025: {Compositions of the sidewalls}
- C08L 21/00: Compositions of unspecified rubbers
- 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

## Abstract

The present invention provides a tire rubber composition that makes it possible to suppress discoloration of tires, and a pneumatic tire formed from the rubber composition. The present invention relates to a tire rubber composition containing a bluing agent.

## Claims

### Claim 1

A tire rubber composition comprising a rubber component, a bluing agent and carbon black,
wherein the bluing agent is at least one member selected from the group consisting of inorganic dyes and pigments, and
wherein the carbon black is present in an amount of 10 to 150 parts by mass, per 100 parts by mass of the rubber component in the tire rubber composition.

### Claim 2 (depends on 1)

The tire rubber composition according to claim 1,
further comprising styrene-butadiene rubber and an antioxidant,
wherein a b* value of the bluing agent satisfies −60<b*<5 and an a* value of the bluing agent satisfies −60<a*<5.

### Claim 3 (depends on 1)

The tire rubber composition according to claim 1,
wherein the bluing agent is present in an amount of 0.2 to 50 parts by mass per 100 parts by mass of a rubber component in the tire rubber composition.

### Claim 4 (depends on 1)

The tire rubber composition according to claim 1,
wherein the tire rubber composition is for use as a sidewall rubber composition.

### Claim 5 (depends on 1)

A pneumatic tire, formed from the tire rubber composition according to claim 1.

### Claim 6

A tire rubber composition which suppresses the discoloration of tires and does not degrade the performance of the flex crack growth resistance of the tires, which comprises a rubber component, a bluing agent and carbon black,
wherein the bluing agent is at least one member selected from the group consisting of inorganic dyes and pigments, and
wherein the carbon black is present in an amount of 10 to 150 parts by mass, per 100 parts by mass of the rubber component in the tire rubber composition.

### Claim 7 (depends on 6)

The rubber composition of claim 6, wherein the bluing agent is present in an amount of 0.3 to 15 parts by mass per 100 parts by mass of the rubber component in the rubber composition.

### Claim 8 (depends on 1)

The tire rubber composition according to claim 1, wherein the carbon black is present in an amount of 30 to 150 parts by mass, per 100 parts by mass of the rubber component in the tire rubber composition.