# US 2014/0196828 A1 · Rubber composition for canvas chafer, and pneumatic tire

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- Number: US 2014/0196828 A1
- Document ID: US20140196828A1
- Status: Published application
- Kind: A1
- Application number: 14/154,872
- Filed: 2014-01-14
- Published: 2014-07-17
- Earliest claimed: 2013-01-15
- Assignees: Sumitomo Rubber Industries, Ltd.
- Applicants: Sumitomo Rubber Industries, Ltd.
- Inventors: Tatsuya MIYAZAKI
- Web page: https://patentgrep.com/patent/US20140196828A1

## CPC

- B60C 15/06: Flipper strips, fillers, or chafing strips {and reinforcing layers for the construction of the bead}
- C08K 3/04: Carbon
- C08L 9/00: Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
- B60C 2001/005: {Compositions of the bead portions, e.g. clinch or chafer rubber or cushion rubber}
- B60C 2015/0614: {characterised by features of the chafer or clinch portion, i.e. the part of the bead contacting the rim}
- C08K 2201/006: Additives being defined by their surface area
- Y10T 152/10828: Chafer or sealing strips
- B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Provided are a rubber composition for a canvas chafer which, despite being low cost, is excellent in rim chafing resistance, resistance to rim damage, and processability (sheeting processability, rubber flow in the tire, adhesion to adjacent components) and performs well with respect to low heat build-up, and a pneumatic tire including the composition. The invention relates to a rubber composition for a canvas chafer, including: an isoprene-based rubber; a carbon black having an N2SA of 65-200 m2/g; and sulfur, wherein an amount of the isoprene-based rubber is 25-80% by mass and an amount of butadiene rubber is not more than 40% by mass, each based on 100% by mass of a rubber component of the rubber composition, and an amount of the carbon black is 40-80 parts by mass and an amount of the sulfur is 1.0-2.7 parts by mass, each per 100 parts by mass of the rubber component.

## Claims

### Claim 1

A pneumatic tire, comprising
a canvas chafer comprising, as a topping composition, a rubber composition for a canvas chafer,
wherein the rubber composition for a canvas chafer comprises:
an isoprene-based rubber;
a carbon black having a nitrogen adsorption specific surface area of 65 to 200 m2/g; and
sulfur,
wherein in the rubber composition for a canvas chafer, an amount of the isoprene-based rubber is 25 to 80% by mass and an amount of butadiene rubber is not more than 40% by mass, each based on 100% by mass of a rubber component of the rubber composition for a canvas chafer, and
an amount of the carbon black is 40 to 80 parts by mass and an amount of the sulfur is 1.0 to 2.7 parts by mass, each per 100 parts by mass of the rubber component.

### Claim 2 (depends on 1)

The pneumatic tire according to claim 1,
wherein the rubber composition for a canvas chafer comprises calcium carbonate, talc, bituminous coal, hard clay, or crushed rubber powder.

### Claim 3 (depends on 1)

The pneumatic tire according to claim 1,
wherein the rubber composition for a canvas chafer comprises 1 to 15 parts by mass of reclaimed rubber powder having an average particle size of 100 μm to 1 mm per 100 parts by mass of the rubber component.

### Claim 4 (depends on 1)

The pneumatic tire according to claim 1, further comprising
a ply adjacent to the canvas chafer, which comprises, as a topping composition, a rubber composition for a ply,
wherein a sulfur content in the rubber composition for a canvas chafer and a sulfur content in the rubber composition for a ply, each per 100 parts by mass of the corresponding rubber component of the rubber composition for a canvas chafer or ply, satisfy the following formula:
(the sulfur content in the rubber composition for a ply)/(the sulfur content in the rubber composition for a canvas chafer)≦3.5.