Pneumatic tire having built-in sealant layer and preparation thereof

• Main Authors: HOLDEN BRIAN DAVID, REITER LEONARD JAMES, BALOGH GEORGE FRANK, DEEVERS SUSAN LYNN, DIROSSI RAYMOND ROBERT
• Format: Patent
• Language: English
• Published: 19.08.2004
• Edition: 7
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; DEVICES OR ARRANGEMENTS RELATED TO TYRES; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; REPAIRING, OR CONNECTING VALVES TO, INFLATABLE ELASTIC BODIESIN GENERAL; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; TYRE CHANGING OR REPAIRING; TYRE INFLATION; USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS; VEHICLE TYRES; VEHICLES IN GENERAL; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

This invention relates to a pneumatic tire having a built-in sealant layer and its preparation. The sealant layer precursor is a layer of a butyl rubber based composition which contains an organoperoxide. The butyl rubber of said precursor is a copolymer of isobutylene and isoprene containing from about 0.5 to about 5, alternately less than 1, mole percent isoprene. The precursor composition contains carbon black and/or coal dust and may contain a dispersion of liquid conjugated diene polymer (e.g. liquid cis 1,4-polyisoprene polymer), short fibers and/or hollow glass microspheres. A layer of the sealant precursor is built into the tire between a sulfur vulcanized halobutyl rubber innerliner and conjugated diene-based rubber of the tire carcass. The butyl rubber of the sealant precursor is partially depolymerized by the organoperoxide during the elevated temperature vulcanization of the tire to form the built-in sealant layer. In one aspect of the invention, said uncured butyl rubber sealant precursor layer composition has a storage modulus G'(80° C.) in a range of about 100 to about 400 kPa and said partially depolymerized butyl rubber sealant layer composition has a storage modulus G' (80° C.) in range of about 5 to about 50 kPa.