Run-flat tire

Patent metadata

Field	Value
Publication number	US-9493041-B2
Application number	US-200913395391-A
Country	US
Kind code	B2
Filing date	Sep 10, 2009
Priority date	Sep 10, 2009
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

The present invention relates to a run-flat tire employing a rubber composition capable of improving processability without reducing the durability during run-flat traveling. More specifically, the present invention relates to a run-flat tire comprising a bead filler 7 and a pair of side-reinforcing rubber layers 8 . At least one of the bead filler 7 and the side-reinforcing rubber layer 8 employs a rubber composition obtained by adding 3 to 10 parts by mass of sulfur and 0.1 to 30 parts by mass of a low-molecular-weight conjugated diene-based polymer (B) having a weight average molecular weight in the range of 2,000 to 10,000, to 100 parts by mass of a rubber component (A) containing at least a natural rubber or polyisoprene rubber and having a weight average molecular weight in the range of 150,000 to 2,000,000.

First claim

The invention claimed is:

1. A run-flat tire comprising a side wall portion, a tread, a carcass, a bead core, and a bead filler,
said bead filler employing a rubber composition obtained by adding 3 to 10 parts by mass of sulfur and 20 to 30 parts by mass of a low-molecular-weight conjugated diene-based polymer (B) having a weight average molecular weight in terms of polystyrene standard in the range of 4,000 to 8,000 measured with a gel permeation chromatography and which is at least one of a homopolymer of 1,3-butadiene and a poly(styrene-co-1,3-butadiene), to 100 parts by mass of a rubber component (A) containing at least a natural rubber or polyisoprene rubber and having a weight average molecular weight in terms of polystyrene standard in the range of 150,000 to 2,000,000 measured with the gel permeation chromatography,
wherein in the polymer (B), the percentage of an aromatic vinyl compound unit relative to all monomer units is less than 4% by mass, and the percentage of a vinyl bonding amount in the conjugated diene compound moiety is in the range of 30% to 80%, and
wherein the rubber component (A) further comprises at least one type selected from the group consisting of a styrene-butadiene copolymer rubber and a polybutadiene rubber.

2. The run-flat tire according to claim 1 , wherein the low-molecular-weight conjugated diene-based polymer (B) is the homopolymer of 1,3-butadiene.

3. The run-flat tire according to claim 1 , wherein the rubber composition further contains a carbon black and/or silica.

4. A run-flat tire comprising a side wall portion, a tread, a carcass, and a side-reinforcing rubber layer,
said side-reinforcing rubber layer employing a rubber composition obtained by adding 3 to 10 parts by mass of sulfur and 20 to 30 parts by mass of a low-molecular-weight conjugated diene-based polymer (B) having a weight average molecular weight in terms of polystyrene standard in the range of 4,000 to 8,000 measured with a gel permeation chromatography and which is at least one of a homopolymer of 1,3-butadiene and a poly(styrene-co-1,3-butadiene), to 100 parts by mass of a rubber component (A) containing at least a natural rubber or polyisoprene rubber and having a weight average molecular weight in terms of polystyrene standard in the range of 150,000 to 2,000,000 measured with the gel permeation chromatography,
wherein in the polymer (B), the percentage of an aromatic vinyl compound unit relative to all monomer units is less than 4% by mass, and the percentage of a vinyl bonding amount in the conjugated diene compound moiety is in the range of 30% to 80%, and
wherein the rubber component (A) further comprises at least one type selected from the group consisting of a styrene-butadiene copolymer rubber and a polybutadiene rubber.

5. A run-flat tire comprising a side wall portion, a tread, a carcass, a bead core, a bead filler, and a side-reinforcing rubber layer,
at least one of said bead filler and said side-reinforcing rubber layer employing a rubber composition obtained by adding 3 to 10 parts by mass of sulfur and 20 to 30 parts by mass of a low-molecular-weight conjugated diene-based polymer (B) having a weight average molecular weight in terms of polystyrene standard in the range of 4,000 to 8,000 measured with a gel permeation chromatography and which is at least one of a homopolymer of 1,3-butadiene and a poly(styrene-co-1,3-butadiene, to 100 parts by mass of a rubber component (A) containing at least a natural rubber or polyisoprene rubber and having a weight average molecular weight in terms of polystyrene standard in the range of 150,000 to 2,000,000 measured with the gel permeation chromatography,
wherein in the polymer (B), the percentage of an aromatic vinyl compound unit relative to all monomer units is less than 4% by mass, and the percentage of a vinyl bonding amount in the conjugated diene compound moiety is in the range of 30% to 80%, and
wherein the rubber component (A) further comprises at least one type selected from the group consisting of a styrene-butadiene copolymer rubber and a polybutadiene rubber.

Assignees

• Matsuo Shigeaki
• Masaki Koji
• Bridgestone Corp

Inventors

• Matsuo Shigeaki
• Masaki Koji

Classifications

• C08L9/00

  Compositions of homopolymers or copolymers of conjugated diene hydrocarbons · CPC title

• C08L21/00

  Compositions of unspecified rubbers · CPC title

• B60C2001/0033

  Compositions of the sidewall inserts, e.g. for runflat · CPC title

• B60C17/0009 Primary

  comprising sidewall rubber inserts, e.g. crescent shaped inserts · CPC title

• C08L7/00

  Compositions of natural rubber · CPC title