Functionalized Tire Tread Rubber for Low Rolling Resistance
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Solution Overview
Problem
Pneumatic vehicle tires face challenges in achieving a balance between rolling resistance, abrasion resistance, and wet grip, with improvements in one property often leading to deterioration in another, such as increased rolling resistance resulting in poor braking behavior.
Innovation Solution
A sulfur-crosslinkable rubber mixture comprising 20-100 phr of functionalized styrene-butadiene copolymer A, with one chain end reacted with polyorganosiloxane and alkylaminosilane, and the other chain end with a polyisoprene group, combined with 30-300 phr of silica and 1-20 phr of blocked or unblocked mercaptosilane as a silane coupling agent, to enhance filler-polymer interaction and processing behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solution-polymerized styrene-butadiene copolymers with different microstructures are used to influence tire properties, then abrasion resistance, wet grip, and rolling resistance can be improved, but the composition complexity increases
Solution Approach 1:
The patent uses a composite rubber composition combining solution-polymerized styrene-butadiene copolymer with natural rubber or synthetic polyisoprene, silica filler, and specific additives to achieve balanced tire performance properties including abrasion resistance, wet grip, and rolling resistance
Solution Approach 2:
The patent optimizes specific parameters including styrene content (15-35 wt%), vinyl content (5-20 wt%), copolymer composition ratios (20-80 parts by weight), and silica content to achieve the desired balance of tire performance properties
2Loss of energy
If rolling resistance is improved, then energy efficiency increases, but braking performance deteriorates
Solution Approach 1:
The patent optimizes the loss factor tan δ at different temperatures by adjusting the copolymer microstructure (vinyl content, styrene content) and filler composition to achieve low rolling resistance (low tan δ at 70°C) while maintaining adequate braking performance (appropriate tan δ at room temperature)
Solution Approach 2:
The composite formulation combines styrene-butadiene copolymer with natural rubber or synthetic polyisoprene and silica to create a material that balances energy dissipation characteristics for both rolling resistance and braking performance
3Loss of energy
If silica content is increased to reduce rolling resistance, then filler-polymer interaction improves, but processing difficulty increases
Solution Approach 1:
The patent employs silane coupling agents as intermediary substances that mediate between the silica filler and the rubber polymer matrix, improving filler-polymer interaction and reducing rolling resistance while maintaining good processing behavior during extrusion and molding
Solution Approach 2:
The patent optimizes the silica content (30-300 phr) and silane coupling agent concentration to achieve the desired balance between reduced rolling resistance and maintained processability
4Loss of energy
If functionalized styrene-butadiene copolymer with polyorganosiloxane and alkylaminosilane is used, then rolling resistance improves, but scorching risk during extrusion increases
Solution Approach 1:
The patent incorporates blocked mercaptosilane as a scorch prevention agent that acts preliminarily during extrusion to prevent premature vulcanization, allowing the functionalized copolymer to be processed without scorching while still achieving the desired rolling resistance improvement
Solution Approach 2:
The blocked mercaptosilane serves as an intermediary protective agent that temporarily prevents harmful scorching during processing, allowing the beneficial functional groups to remain inactive until the extrusion process is complete
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The rubber mixture significantly improves rolling resistance while maintaining good processing behavior and preventing scorching during extrusion, resulting in enhanced tire performance with increased rebound elasticity and reduced heat build-up.
Implementation Method 1
functionalized at one chain end by reaction with at least one polyorganosiloxane and at least one alkylaminosilane
Implementation Method 2
1 to 20 phr of at least one blocked and/or unblocked mercaptosilane as a silane coupling agent
Implementation Method 3
sulfur-crosslinkable rubber compound
Data Source
AI summary
The invention relates to a sulfur-curable rubber compound and a vehicle tire with a tread that consists at least partially of such a sulfur-vulcanized rubber compound. To improve rolling resistance, the sulfur-curable rubber compound contains at least 20-100 phr of at least one functionalized styrene-butadiene copolymer A, wherein the functionalized styrene-butadiene copolymer A is at least partially functionalized at one chain end by reaction with at least one polyorganosiloxane and at least one alkylaminosilane, and wherein the functionalized styrene-butadiene copolymer A is functionalized at the other chain end with a polyisoprene group containing isoprene and styrene units, wherein the isoprene content in the polyisoprene group is more than 90 wt.-%, - up to 80 phr of at least one further diene rubber, - 30 to 300 phr of at least one silica and - 1 to 20 phr of at least one blocked and/or unblocked mercaptosilane as a silane coupling agent.