Silica-Filled Tire Tread Rubber for Rolling Resistance and Dry Traction
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Solution Overview
Problem
Formulating tire tread rubber compositions that improve one property, such as rolling resistance, often leads to deterioration of another property, such as dry traction, presenting a challenge in balancing performance characteristics.
Innovation Solution
A tire tread rubber composition comprising specific ratios of styrene-butadiene rubber and polybutadiene rubber, reinforcing silica filler, limited carbon black filler, hydrocarbon resin, and a cure package, optimized to achieve a balanced performance by controlling glass transition temperature (Tg) and filler content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the rubber composition is formulated to improve rolling resistance, then rolling resistance is reduced, but dry traction deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the glass transition temperature (Tg) of the polybutadiene rubber to be less than −101° C. and adjusting the vinyl bond content of styrene-butadiene rubber to no more than 20%. These specific parameter adjustments optimize the rubber's viscoelastic properties to simultaneously improve rolling resistance and maintain dry traction performance.
Solution Approach 2:
The patent uses composite materials by combining specific ratios of polybutadiene rubber (30-60 parts) and styrene-butadiene rubber (40-60 parts) with reinforcing silica filler (81-120 phr) and limited carbon black filler (0-15 phr). This composite formulation creates a synergistic effect where the rubber blend provides energy efficiency while the filler system maintains traction.
2Reliability
If silica filler content is increased to improve traction, then dry traction is enhanced, but rolling resistance increases
Solution Approach 1:
The patent applies parameter changes by setting the silica filler content within the specific range of 81-120 phr and combining it with polybutadiene rubber having Tg < −101° C. This specific parameter combination allows the silica network to provide traction enhancement while the low Tg rubber matrix maintains flexibility and reduces energy loss, preventing excessive rolling resistance.
3Reliability
If the rubber composition is optimized for one performance characteristic, then that characteristic is improved, but other performance characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes through multiple controlled variables: polybutadiene Tg < −101° C., SBR vinyl bond content ≤ 20%, silica content 81-120 phr, and carbon black content 0-15 phr. By simultaneously optimizing these parameters within specific ranges, the composition achieves balanced performance across multiple characteristics including rolling resistance, dry traction, and overall versatility.
Solution Approach 2:
The patent uses composite materials by creating a multi-component system where polybutadiene rubber, styrene-butadiene rubber, silica filler, and carbon black filler work synergistically. This composite approach allows different components to contribute to different performance aspects, achieving overall performance balance rather than optimizing a single characteristic at the expense of others.
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 composition achieves improved rolling resistance and dry traction performance by precisely balancing the ingredients, enhancing overall tire tread properties without compromising on other essential characteristics.
Implementation Method 1
polybutadiene rubber having a cis bond content of at least 95% and a Tg of less than −101° C.
Implementation Method 2
at least one reinforcing silica filler in an amount of 81-120 phr
Implementation Method 3
11-35 phr of at least one hydrocarbon resin having a Tg of about 30 to about 50° C.
Data Source
AI summary
Disclosed herein are tire tread rubber compositions comprising a specified elastomer component, reinforcing silica filler, a specified hydrocarbon resin, a cure package, and optionally oil. The elastomer component includes styrene-butadiene rubber and polybutadiene.