Tire Tread Rubber Composition for Wear and Wet Grip Balance
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Solution Overview
Problem
It is challenging to improve tire wear characteristics without compromising wet skid resistance and traction, as these properties are viscoelastically inconsistent and typically require trade-offs between high rebound and high energy loss rubbers in tire tread compounds.
Innovation Solution
A pneumatic tire tread composition comprising a blend of solution-polymerized and emulsion-polymerized styrene-butadiene rubbers, cis-1,4 polybutadiene, processing oil, carbon black, silica, a sulfur-containing organosilicon compound, and a coumarone-indene resin, which balances abrasion resistance and traction by creating dual elastomer phases with distinct Tan delta peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rubbers with high rebound are used to reduce rolling resistance and improve treadwear, then wear characteristics improve, but wet skid resistance deteriorates
Solution Approach 1:
The patent divides the rubber system into multiple distinct segments: solution-polymerized SBR (first and second types), emulsion-polymerized SBR, and polybutadiene. Each segment contributes different viscoelastic properties, allowing the composite to achieve both high rebound (for wear resistance) and appropriate energy loss (for wet skid resistance) that cannot be achieved by a single rubber type alone.
Solution Approach 2:
The invention creates a composite rubber composition by combining multiple rubber types with specific properties: solution-polymerized SBR with controlled styrene content and vinyl 1,2 content, emulsion-polymerized SBR, and polybutadiene. This composite approach allows synergistic effects where the combination achieves superior wet skid resistance and treadwear characteristics compared to individual rubber components, resolving the contradiction between wear resistance and wet traction.
2Object-generated harmful factors
If rubbers with large energy loss are used to increase wet skid resistance, then wet skid resistance improves, but rolling resistance increases
Solution Approach 1:
The patent segments the energy dissipation function across different rubber components. The emulsion-polymerized SBR and polybutadiene contribute to energy loss for wet skid resistance, while the solution-polymerized SBR components maintain lower energy loss for reduced rolling resistance. This segmentation allows independent optimization of each function within the composite system.
Solution Approach 2:
The invention carefully controls specific parameters of each rubber component: bound styrene content (30-50% for first SBR, 25-45% for second SBR), vinyl 1,2 content (10-40% for first SBR, 20-60% for second SBR), and glass transition temperature ranges. By adjusting these parameters, the patent optimizes the balance between energy loss (for wet skid) and rolling resistance without compromising overall performance.
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 composition achieves improved rolling resistance, wet and dry braking performance, and treadwear characteristics without compromising on any single property, indicating a better balance of abrasion resistance and traction.
Implementation Method 1
0.5 to 20 phr of a sulfur containing organosilicon compound
Implementation Method 2
the dynamic viscoelastic properties of the rubbers utilized in making the tire
Implementation Method 3
creating dual elastomer phases with distinct Tan delta peaks
Data Source
AI summary
A rubber composition for a tread of a pneumatic tire is disclosed. The rubber composition comprises: (A) 30 to 70 phr of a first styrene-butadiene rubber, wherein the first styrene-butadiene rubber is a solution-polymerized styrene-butadiene rubber with a Tg of from -40ºC to -20ºC or an emulsion-polymerized styrene-butadiene rubber with a Tg of from -40ºC to -20ºC; (B) 20 to 60 phr of solution-polymerized styrene-butadiene rubber a Tg of from -30ºC to -5ºC; (C) 5 to 20 phr of cis-1,4 polybutadiene having a Tg of from -110ºC to - 90ºC; (D) 30 to 60 phr of processing oil; (E) 5 to 20 phr of carbon black; (F) 80 to 130 phr of silica; (G) 0.5 to 20 phr of a sulfur containing organosilicon compound; and (H) 5 to 20 phr of resin.