Tire Tread Rubber Composition Balancing Wear, Wet Grip, and Rolling Resistance
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Solution Overview
Problem
Existing rubber compositions for tire treads struggle to achieve a well-balanced and compatible improvement in wear resistance, low rolling resistance, and wet performance at higher levels than previously achieved.
Innovation Solution
A rubber composition comprising styrene-butadiene rubber, white filler, and a specific thermoplastic resin with a blending ratio and satisfying certain tan δ curve relationships, along with optional plasticizer, to enhance wear resistance, low rolling resistance, and wet performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an aromatic modified terpene resin and an oil are blended in the rubber composition to improve wear resistance, then wear resistance is improved, but rolling resistance and wet performance cannot be sufficiently improved
Solution Approach 1:
The patent changes the chemical composition parameters by replacing aromatic modified terpene resin with a specific thermoplastic resin (polyester resin, polyamide resin, or polyurethane resin) and adjusts the oil content to 5-30 parts by mass. This parameter change enables simultaneous improvement of wear resistance, rolling resistance, and wet performance that was not achievable with the previous aromatic modified terpene resin formulation.
Solution Approach 2:
The patent creates a composite rubber composition system combining diene rubber (70-100 parts), white filler (20-150 parts), thermoplastic resin (5-30 parts), and oil (5-30 parts). This composite material approach with specifically selected components and ratios achieves the multi-performance balance that single-component systems cannot provide.
2Adaptability or versatility
If the thermoplastic resin and plasticizer are blended at specific ratios to achieve higher wear resistance, low rolling resistance, and wet performance, then all three performance parameters are improved, but the formulation becomes more complex
Solution Approach 1:
The patent establishes specific parameter ranges: thermoplastic resin (5-30 parts), plasticizer (0-25 parts), with thermoplastic resin comprising 75-100 mass% of the total. These parameter specifications provide a clear formulation framework that simplifies the complexity while ensuring optimal performance across all three parameters.
3Adaptability or versatility
If the total amount of thermoplastic resin and plasticizer is controlled at 20 parts by mass or more and less than 50 parts by mass, then the dynamic viscoelasticity is optimized for balanced performance, but the formulation range becomes more restricted
Solution Approach 1:
The patent defines a specific parameter range for the total amount of thermoplastic resin and plasticizer (20-50 parts by mass) to optimize the tan δ curve characteristics. This restricted range ensures the half-width σbf is 4.0°C or more and |tan δbf - tan δaf| is 0.02 or less, achieving the desired dynamic viscoelasticity for balanced wear resistance, rolling resistance, and wet 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 composition provides enhanced wear resistance, low rolling resistance, and wet performance beyond previous levels by optimizing the blending ratios and dynamic viscoelasticity properties.
Implementation Method 1
a half-width σbf (° C.) in a temperature dependent tan δ curve of the rubber composition, tan δbf representing a value of tan δ at a temperature 90° C. higher than a peak temperature where tan δ is at maximum
Implementation Method 2
A difference Tgr-Tgp between a minimum glass transition temperature Tgp (° C.) among glass transition temperatures of the at least one styrene-butadiene rubber and a glass transition temperature Tgr (° C.) of the thermoplastic resin is preferably 100° C. or more
Data Source
AI summary
A rubber composition contains from 20 to 150 parts by mass of a white filler, and a total of 20 to less than 50 parts by mass of a thermoplastic resin and, optionally, a plasticizer, in 100 parts by mass of a diene rubber containing a styrene-butadiene rubber, where the thermoplastic resin accounts for 75 mass % or more with respect to the total amount. The rubber composition satisfies |σbf-σaf≥4 and |tan δbf-tan δaf|≤0.02, where σbf (° C.) represents a half-width in a temperature dependent tan δ curve of the rubber composition, tan δb represents tan δ at a temperature 90° C. higher than a peak temperature where tan δ is at maximum, σaf (° C.) represents a half-width of a temperature dependent tan δ curve of a treated rubber composition by immersion of the rubber composition in toluene and drying, and tan δaf represents tan δ at a temperature 90° C. higher than a peak temperature where tan δ is at maximum.