Pre-formed apex/bead composite and tire with pre-apexed bead
AssigneeThe Goodyear Tire & Rubber Company
InventorsPaul Harry Sandstrom, James Joseph Golden, Joseph Henry Laco
Life of this patent
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Abstract
The invention relates to preparation of an apex/bead composite as a pre-apexed tire bead, and pneumatic tire containing such pre-apexed bead. The invention relates to such pre-apexed bead where the apex is comprised of a rubber composition which contains a syndiotactic-1,2-polybutadiene polymer.
Claims18
A method of preparing a tire apex/bead composite as a pre-apexed bead comprises mixing a sulfur curable rubber composition and extruding the mixed uncured sulfur curable rubber composition through a suitable die to form and apply an uncured rubber apex strip onto and circumferentially around the outer peripheral surface of an annular tire bead, where said tire bead is comprised of uncured sulfur curable rubber encapsulated plurality of wire cords,
- whereby the radially outer portion of the uncured rubber apex strip is caused by such method to be stretched beyond its original extruded length and beyond the length of the radially inner portion of the apex, wherein the composition of the rubber apex is comprised of:
- (A) at least one diene-based elastomer comprised of at least one of cis 1,4-polyisoprene, polybutadiene and styrene/butadiene rubber,
- (B) about 1 to about 10 parts by weight thermoplastic syndiotactic-1,2-polybutadiene per 100 parts by weight of diene-based elastomers contained in the apex rubber composition, wherein the thermoplastic syndiotactic-1,2-polybutadiene has a melting point (MP) in a range of from about 180° C. to about 230° C. and is provided as an alloy comprised of thermoplastic syndiotactic-1,2-polybutadiene with at least one of cis 1,4-polyisoprene rubber and polybutadiene rubber,
- (C) about 30 to about 120 phr of reinforcing filler comprised of:
- (1) rubber reinforcing carbon black, or
- (2) combination of rubber reinforcing carbon black and precipitated silica together with a coupling agent for the precipitated silica having a moiety reactive with hydroxyl groups on the precipitated silica and another different moiety interactive with said diene-based elastomer(s).
The method of claim wherein the reinforcing filler is limited to rubber reinforcing carbon black.
A pre-apexed annular tire bead is provided which comprises an annular tire bead comprised of uncured rubber encapsulated wire cords where said bead contains a uncured rubber apex positioned onto and circumferentially around the outer periphery of the annular bead,
- wherein the radially outer portion of the uncured rubber apex on the annular bead has a stretched length greater than the length of its radially inner portion,
- wherein the composition of the rubber apex is comprised of:
- (A) at least one diene-based elastomer comprised of at least one of cis 1,4-polyisoprene, polybutadiene and styrene/butadiene rubber,
- (B) about 1 to about 10 parts by weight thermoplastic syndiotactic-1,2-polybutadiene per 100 parts by weight of diene-based elastomers contained in the apex rubber composition, wherein the thermoplastic syndiotactic-1,2-polybutadiene has a melting point (MP) in a range of from about 180° C. to about 230° C. and is provided as an alloy comprised of thermoplastic syndiotactic-1,2-polybutadiene with at least one of cis 1,4-polyisoprene rubber and polybutadiene rubber,
- (C) about 30 to about 120 phr of reinforcing filler comprised of:
- (1) rubber reinforcing carbon black, or
- (2) combination of rubber reinforcing carbon black and precipitated silica together with a coupling agent for the precipitated silica having a moiety reactive with hydroxyl groups on the precipitated silica and another different moiety interactive with said diene-based elastomer(s).
Dependencies are inferred from the claim text.