Rubber Composition for Balanced Tire Tread Performance
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Solution Overview
Problem
Tires face a challenge in balancing wet skid resistance, low rolling resistance, and wear characteristics, as rubbers with high rebound are used for reduced rolling resistance but those with high energy loss are needed for improved wet skid resistance, making it difficult to achieve these properties simultaneously.
Innovation Solution
A vulcanizable rubber composition for tire treads comprising styrene-butadiene rubber, natural or synthetic polyisoprene, cis-1,4 polybutadiene, silica, a combination resin, oil, and a sulfur-containing organosilicon compound, optimized in specific parts by weight ratios to balance dynamic viscoelastic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rubbers with high rebound are used to reduce rolling resistance, then rolling resistance is improved, but wet skid resistance deteriorates
Solution Approach 1:
The patent uses a composite rubber system combining styrene-butadiene rubber (SBR) with polybutadiene rubber (BR) and natural rubber (NR) in specific ratios. The SBR provides structural stability and wet skid resistance, while the BR and NR components contribute high rebound properties to reduce rolling resistance. This composite approach allows simultaneous optimization of both contradictory properties through synergistic material combination.
Solution Approach 2:
The patent optimizes specific parameters of the rubber components: SBR with 23-43% vinyl content and -30°C to -10°C Tg, BR with -100°C to -90°C Tg, and specific molecular weight distributions. By precisely controlling these parameters, the composition achieves balanced viscoelastic properties that provide both low rolling resistance (through appropriate rebound) and good wet skid resistance (through controlled energy loss at relevant frequencies).
2Reliability
If rubbers with high energy loss are used to improve wet skid resistance, then wet skid resistance is improved, but rolling resistance worsens
Solution Approach 1:
The patent employs a multi-component rubber composite where SBR (providing wet skid resistance through controlled energy loss) is combined with BR and NR (providing high rebound). The specific formulation ratios and molecular weight distributions create a synergistic effect where the energy loss characteristics are optimized for wet traction without excessive rolling resistance penalty.
Solution Approach 2:
The patent specifies precise Tg ranges and vinyl content parameters for each rubber component to control the frequency-dependent viscoelastic behavior. The SBR's -30°C to -10°C Tg and 23-43% vinyl content provide optimal energy loss characteristics for wet skid resistance, while the overall composition maintains adequate rebound to limit rolling resistance increase.
3Duration of action of stationary object
If mixtures of synthetic and natural rubber are used to balance viscoelastic properties, then wear characteristics are improved, but wet skid resistance and traction characteristics deteriorate
Solution Approach 1:
The patent uses a specific composite formulation combining SBR (70-90 parts), polybutadiene (10-30 parts), and natural rubber (0-20 parts) per 100 parts total rubber. This composite provides enhanced wear resistance through the durable SBR matrix while maintaining wet skid resistance through the viscoelastic properties of the BR and NR components. The molecular weight distribution and vinyl content parameters are optimized to balance wear and traction.
Solution Approach 2:
The patent optimizes molecular weight parameters (Mw, Mn, and Mw/Mn ratio) and vinyl content (23-43%) of the SBR, along with Tg ranges for all components, to achieve the desired balance. These parameter controls ensure that the wear resistance from the SBR matrix does not compromise the wet skid resistance provided by the viscoelastic properties of the composite system.
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 significantly improves wet braking, rolling resistance, and treadwear characteristics, demonstrating enhanced performance across these critical tire properties.
Implementation Method 1
from 5 to 25 phr of a sulfur containing organosilicon compound
Implementation Method 2
a vulcanizable rubber composition
Data Source
AI summary
A rubber composition and a tire comprising such a rubber composition is disclosed. The rubber composition comprises: from 75 to 85 phr of a styrene-butadiene rubber having a bound styrene content of from 30 to 50 percent by weight, a vinyl 1,2 content of from 10 to 30 percent by weight based on the rubber weight, and a Tg in a range of from -40ºC to - 20ºC; from 0 to 25 phr, alternatively from 5 phr to 15 phr, of natural rubber or synthetic polyisoprene; from 0 to 20 phr, alternatively from 5 phr to 15 phr, of cis-1,4 polybutadiene having a Tg in a range of from -110ºC to -90ºC; from 100 to 150 phr of silica; from 20 to 40 phr of a combination resin comprising a polyterpene resin, an alkylphenol formaldehyde resin, and a rosin acid; from 30 to 60 phr of oil; and from 5 to 25 phr of a sulfur containing organosilicon compound.