Tire Tread Rubber Composition Using β-Pinene Resin Phase Separation
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Solution Overview
Problem
Existing rubber compositions for tire treads face challenges in simultaneously achieving low-temperature performance and wet grip performance, as the incorporation of butadiene rubber for low-temperature performance tends to deteriorate wet grip performance, and vice versa, due to conflicting effects on glass transition temperature and compatibility with silica and resins.
Innovation Solution
A rubber composition comprising 100 parts by mass of a diene rubber component with 40 parts by mass or more of modified butadiene rubber, 60 to 200 parts by mass of silica, and 20 to 60 parts by mass of a terpene-based resin with a β-pinene unit content of 40 mass% or more, which phase-separates to maintain low-temperature performance while improving wet grip performance, and uses modified butadiene rubber to enhance silica dispersibility and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If butadiene rubber is incorporated to improve low-temperature performance, then low-temperature performance is improved, but wet grip performance deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters of the butadiene rubber by introducing polar groups (nitrile, carboxyl, or hydroxyl groups) at the terminal positions of the butadiene rubber chains. This parameter change allows the rubber to maintain low glass transition temperature (improving low-temperature performance) while simultaneously providing polar interactions with silica and resin (improving wet grip performance). The specific parameter change is the introduction of polar functional groups at terminal positions, which creates dual functionality in the same polymer chains.
2Reliability
If resin is added to improve wet grip performance, then wet grip performance is improved, but low-temperature performance deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by specifying precise ratios of butadiene rubber (40-80 mass%), silica (50-150 parts per 100 mass% rubber), and resin (5-30 parts per 100 mass% rubber). These parameter changes create a balanced composition where the resin content is optimized to provide wet grip improvement without excessive increase in glass transition temperature. The parameter optimization allows simultaneous achievement of both performance targets.
3Reliability
If silica is incorporated to improve wet grip performance, then wet grip performance is improved, but processability deteriorates
Solution Approach 1:
The patent introduces polar groups (nitrile, carboxyl, or hydroxyl groups) on the butadiene rubber chains as intermediary functional groups that mediate the interaction between silica and the rubber matrix. These polar groups act as intermediaries that enhance silica dispersibility through polar interactions, thereby improving wet grip performance while maintaining good processability. The intermediary polar groups facilitate uniform silica distribution without causing excessive stickiness or processing difficulties.
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 rubber composition simultaneously achieves low-temperature and wet grip performance while improving processability by ensuring uniform silica dispersion and reducing stickiness, making it suitable for all-season tires.
Implementation Method 1
a rubber composition comprising 100 parts by mass of a diene rubber component with 40 parts by mass or more of modified butadiene rubber, 60 to 200 parts by mass of silica, and 20 to 60 parts by mass of a terpene-based resin with a β-pinene unit content of 40 mass% or more, which phase-separates to maintain low-temperature performance while improving wet grip performance
Implementation Method 2
uses modified butadiene rubber to enhance silica dispersibility and processability
Data Source
AI summary
A rubber composition for a tire tread according to an embodiment includes: 100 parts by mass of a diene rubber component containing 40 parts by mass or more of a modified butadiene rubber; 60 to 200 parts by mass of silica; and 20 to 60 parts by mass of a terpene-based resin having a β-pinene unit content of 40 mass% or more.