# US 5,341,862 A · Flame-retardant rubber tires

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- Number: US 5,341,862 A
- Document ID: US5341862A
- Status: Granted
- Kind: A
- Application number: 07/974,519
- Filed: 1992-11-12
- Granted: 1994-08-30
- Earliest claimed: 1991-11-14
- Assignees: Bridgestone Corporation
- Inventors: Takatsugu Hashimoto; Keizo Akutagawa; Kazuo Yagawa; Makoto Tanaka; Junichi Yamagishi; Kazuo Hachiya
- Web page: https://patentgrep.com/patent/US5341862A

## CPC

- B60C 11/00: Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C 1/00: Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
- B60C 1/0016: {Compositions of the tread}
- B60C 11/1346: {covered by a rubber different from the tread rubber}
- Y10T 152/10495: Pneumatic tire or inner tube
- B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

In a flame-retardant rubber tire comprising an outer rubber body portion consisting essentially of a tread rubber layer, a sidewall rubber layer extending inward from each side edge of the tread rubber layer toward the vicinity of a bead portion in radial direction and a rubber chafer layer arranged in the vicinity of the bead portion, a flame-retardant rubber composition having an oxygen index of not less than 19.8 but not more than 27.5 is disposed so as to amount at least 20% by weight of the tread rubber layer. Such rubber tires are used in electric vehicles, automobiles, airplanes and the like and have excellent self-extinguishing property and flame-delaying property without damaging other rubber properties.

## Claims

### Claim 1

A flame-retardant rubber tires comprising: an outer rubber body portion consisting essentially of a tread rubber layer, a sidewall rubber layer extending inward from each side edge of the tread rubber layer toward the vicinity of a bead portion in radial direction and a rubber chafer layer arranged in the vicinity of the bead portion, and a reinforcing body located inside the outer rubber body portion, at least a portion of the outer rubber body portion comprised of one or more flame-retardant rubber layers having an oxygen index (O.I.) in the range of 19.8 to 27.5, and an absolute value of total (O.I.) .times.S.times.V.times.U values of the flame-retardant rubber layers is not less than 10 as a flame retardance when S is a ratio of surface area of the flame-retardant rubber layer to a full surface area of the outer rubber body portion, V (kg) is a weight of the flame-retardant rubber layer and U is a ratio of weight (kg) of the flame-retardant rubber layer to total weight (kg) of the outer rubber body portion.

### Claim 2 (depends on 1)

The flame-retardant rubber tire according to claim 1, wherein said surface area ratio S of flame-retardant rubber layer to a full surface area of said outer rubber body portion exposed after the mounting onto a normal rim is at least 0.30 and said ratio U of weight of said flame-retardant rubber layer to total weight of said outer rubber body portion is not less than 0.40.