Alkoxysilane Polybutadiene Tread for Low Rolling Resistance
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Solution Overview
Problem
Tires face a challenge in balancing good rolling resistance and wet traction characteristics, as improvements in one property often lead to a reduction in the other, due to the viscoelastic inconsistencies of rubber compounds used in tire treads.
Innovation Solution
A pneumatic tire tread composition incorporating a diene elastomer, silica, blocked mercaptosilane, and low molecular weight polybutadiene functionalized with an alkoxysilane group, which includes a blend of styrene-butadiene rubber and natural or synthetic polyisoprene, optimized to improve hysteresis loss characteristics and traction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rubbers with high rebound are used to reduce rolling resistance and improve treadwear, then wear characteristics improve, but wet skid resistance decreases
Solution Approach 1:
The patent changes the molecular weight parameter of polybutadiene rubber to a relatively low range (50-200 kDa), which alters the viscoelastic properties of the rubber compound. This parameter change enables the tread to achieve both low rolling resistance and good wet skid resistance by optimizing the balance between elasticity and energy dissipation at different temperatures and deformation rates.
Solution Approach 2:
The patent creates a composite rubber compound by combining multiple rubber types (styrene-butadiene rubber and polybutadiene rubber) with specific proportions. This composite formulation allows the tread to exhibit both high rebound characteristics for low rolling resistance and sufficient energy loss for wet skid resistance, resolving the contradiction between these two opposing requirements.
2Reliability
If rubbers with large energy loss are used to increase wet skid resistance, then wet traction improves, but rolling resistance increases
Solution Approach 1:
The patent modifies the molecular weight parameter of polybutadiene rubber to a relatively low range (50-200 kDa), which optimizes the energy dissipation characteristics. This parameter adjustment allows the rubber to provide sufficient energy loss for wet skid resistance while maintaining high rebound properties that limit excessive energy loss and keep rolling resistance low.
Solution Approach 2:
The patent applies different rubber compositions to different regions of the tread compound formulation. By using a specific combination of styrene-butadiene rubber and low molecular weight polybutadiene rubber in controlled proportions, the compound achieves localized optimization where energy loss is sufficient for wet traction but not excessive to the point of increasing rolling resistance.
3Reliability
If mixtures of synthetic and natural rubber are used to balance viscoelastic properties, then both rolling resistance and wet traction can be improved, but the complexity of the rubber compound increases
Solution Approach 1:
The patent employs a composite rubber compound consisting of styrene-butadiene rubber and polybutadiene rubber in specific proportions (70-90 parts and 10-30 parts respectively per 100 parts of total rubber). This defined composite formulation balances viscoelastic properties to achieve both good rolling resistance and wet traction without requiring overly complex multi-component systems.
Solution Approach 2:
The patent simplifies the rubber compound complexity by controlling the molecular weight parameter of polybutadiene rubber within a specific range (50-200 kDa). This parameter control allows for predictable performance and simplified formulation compared to using multiple different rubber types with varying molecular weights and properties.
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 tire tread composition achieves a compromise between low rolling resistance and good wet traction, enhancing the overall performance by inhibiting energy loss and improving hysteresis characteristics.
Implementation Method 1
improve hysteresis loss characteristics
Implementation Method 2
dynamic viscoelastic properties of the rubbers
Data Source
AI summary
Disclosed is a pneumatic tire having a tread, the tread comprising a rubber composition comprising a diene elastomer, silica, a blocked mercaptosilane, and a polybutadiene functionalized with an alkoxysilane functional group. The polybutadiene has a weight average molecular weight (Mw) in a range of from 1000 to 25000 g/gmol.