US 6,962,181 B2Granted

Pneumatic tire having built-in sealant layer and preparation thereof

AssigneeThe Goodyear Tire & Rubber Company

InventorsSusan Lynn Deevers, Raymond Robert DiRossi, George Frank Balogh, Brian David Holden, Leonard James Reiter

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Abstract

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.

Claims9

Dependent claims

A pneumatic tire having a built-in puncture sealing layer wherein said puncture sealing layer contains an at least partially organoperoxide-depolymerized butyl rubber-based sealant layer positioned between a sulfur vulcanized halobutyl rubber tire innerliner and a sulfur vulcanized diene-based vulcanized conjugated diene-based tire carcass, wherein said sealant layer is a polymeric composition having a storage modulus (G′) in a range of from about 5 to about 50, alternately about 5 to about 30, kPa, which is exclusive of polyisobutylene additive, and is comprised of, based upon parts by weight per 100 parts by weight of said partially depolymerized butyl rubber:

(A) a partially organoperoxide-depolymerized butyl rubber as a copolymer of isobutylene and isoprene, wherein said copolymer prior to such depolymerization contains from about 0.5 to about 5 percent units derived from isoprene, and correspondingly from about 95 to about 99.5 weight percent units derived from isobutylene, and, based upon parts by weight per 100 parts by weight partially depolymerized butyl rubber (phr) of:
(B) particulate filler comprised of about 5 to about 90 phr of rubber reinforcing carbon black and coal dust, and, optionally at least one of:
(1) from zero to about 6 phr of short fibers, and
(2) from zero to about 20 phr of hollow glass microspheres;
(C) from zero to about 20 phr of rubber processing oil having a maximum aromatic content of about 15 weight percent;
(D) from 1 to about 10 phr of liquid polyisoprene having a weight average molecular weight in a range of from about 35,000 to about 65,000.

3 more elements

A pneumatic tire having a puncture sealing ability comprised of an assembly of components comprised of an outer circumferential sulfur curable rubber tread, at least one sulfur curable rubber carcass ply supporting said tread and an inner sulfur curable halobutyl rubber tire innerliner layer, is prepared by:

(A) positioning a layer of an uncured butyl rubber-based rubber composition, exclusive of sulfur curative, as a sealant layer precursor between said innerliner and rubber carcass, wherein said butyl rubber based composition has a storage modulus G′ (80° C.) in a range of from about 100 to about 400 kPa, wherein said sealant precursor butyl rubber composition is comprised of, based upon parts by weight per 100 parts of butyl rubber (phr):
(1) 100 phr of butyl rubber as a copolymer of isobutylene and isoprene which contains about 0.5 to about 5 mole percent units derived from isoprene and, correspondingly about 95 to about 99.5 mole percent derived from isobutylene, and, based upon parts by weight per 100 parts of said butyl rubber (phr);
(2) particulate filler comprised of about 5 to about 90 phr of rubber reinforcing carbon black and coal dust, and optionally
(a) from zero to 6 phr of short fibers, and/or
(b) from zero to about 20 phr of hollow glass microspheres;
(3) from zero to about 20 phr of rubber processing oil, having a maximum aromatic content of about 15 weight percent;
(4) from 1 to about 10 phr of liquid polyisoprene having a weight average molecular weight in a range of from about 35,000 to about 65,000;
and
(5) about 0.5 to about 10 phr of active organoperoxide compound;
and
(B) vulcanizing said tire assembly in a suitable mold at a temperature in a range of from about 150° C. to about 175° C. for a sufficient period of time to partially depolymerize said butyl rubber and thereby form a built-in sealant layer having a storage modulus property G′ (80° C.) in a range of from about 5 to about 50 kPa.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/368,259Filed 17 Feb 2003
Published: US 2004/0159386 A119 Aug 2004
Granted: 8 Nov 2005
Term ends: Not estimatedThe source records don’t support an estimate.

Classification23 codes

B29D 30/0685
Parts of pneumatic tyres; accessories, auxiliary operations: incorporating auto-repairing or self-sealing arrangements or agents on or into tyres
B29C 73/163
Auto-repairing or self-sealing arrangements or agents: sealing compositions or agents, e.g. combined with propellant agents
B29C 73/22
Auto-repairing or self-sealing arrangements or agents: the article containing elements including a sealing composition, e.g. powder being…
B60C 1/00
Tyres characterised by the chemical composition or the physical arrangement or mixture