Stereoregular SBR Tread Compound for High-Temperature Grip
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Solution Overview
Problem
High-performance tires face challenges in maintaining grip and durability at high temperatures while minimizing rolling resistance, as existing elastomeric compositions often compromise on mechanical properties and hysteresis values, leading to issues like tread weakness and reduced grip during high-speed maneuvers.
Innovation Solution
Incorporating a stereoregular styrene-butadiene elastomeric copolymer with a styrene content higher than 30% by weight and a molecular weight greater than 500,000 Dalton, which is crosslinked with other elastomeric polymers, to create a tread compound that maintains high hysteresis and mechanical properties at high temperatures while reducing thermoplasticity and rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If large amounts of styrene-butadiene copolymers (SBR) are used in the elastomeric composition, then the tread shows reduced thermoplasticity and maintains rigidity at high temperatures, but the hysteresis and grip are reduced
Solution Approach 1:
The patent uses a composite elastomeric composition combining stereoregular SBR with at least one other elastomeric polymer (such as polybutadiene, polyisoprene, or acrylonitrile-butadiene copolymer). This composite approach allows the stereoregular SBR to provide thermoplasticity control and heat resistance, while the other elastomeric polymer contributes hysteresis and grip, thus resolving the contradiction between maintaining rigidity at high temperatures and preserving grip.
Solution Approach 2:
The patent specifies precise parameter ranges for the stereoregular SBR, including styrene content (20-40 wt%), molecular weight (500,000-2,000,000 Dalton), and microstructure (1,2-addition: 30-70%, 1,4-cis: 5-30%, 1,4-trans: 5-30%). By controlling these parameters, the composition achieves optimal balance between thermoplasticity reduction and grip maintenance.
2Strength
If the hysteresis of the elastomeric material is increased to ensure good road holding at high temperatures, then the grip and resistance to laceration improve, but the rolling resistance increases
Solution Approach 1:
The patent creates local quality differentiation within the tread compound by using stereoregular SBR with specific microstructural composition. The controlled 1,2-addition content (30-70%) provides localized hysteresis enhancement at the contact patch for improved grip, while the overall composition design limits excessive energy loss, thus reducing rolling resistance compared to conventional high-hysteresis compounds.
3Temperature
If materials with high glass transition temperature are introduced into the elastomeric compound to raise the glass transition of the tread, then the rigidity at high temperatures improves, but the mechanical properties and resistance to laceration are compromised
Solution Approach 1:
Instead of using expensive high glass transition temperature materials that compromise mechanical properties, the patent employs stereoregular SBR with controlled microstructure that naturally provides appropriate thermal characteristics. This approach achieves the desired temperature performance without sacrificing resistance to laceration, effectively replacing the need for short-living compromise materials.
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 solution provides improved resistance to laceration and abrasion, enhanced grip under extreme conditions, and reduced sensitivity to temperature changes, resulting in a more consistent and durable tire performance.
Implementation Method 1
a crosslinked elastomeric material obtained by crosslinking a crosslinkable elastomeric composition
Implementation Method 2
High hysteresis accompanied by high values for the mechanical properties may give the tyre tread high grip and high resistance to abrasion and to laceration
Implementation Method 3
the tread should show reduced thermoplasticity, in other words it should remain sufficiently rigid as the working temperature increases
Data Source
AI summary
A tyre for wheels of vehicles, in particular motor vehicles, is described. The tyre has a tread with at least one iso-styrene/trans-butadiene elastomeric copolymer with a styrene content higher than 30% by weight with respect to the total weight of copolymer and a molecular weight higher than 500,000. The tread has improved dynamic-mechanical behaviour at high temperatures, with higher dynamic modulus and hysteresis values, and at the same time better properties at break, optimum elasticity at low temperature and higher abrasion resistance.