Tire Tread Rubber Composition Balancing Wet Grip and Cold Flexibility
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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 incorporating butadiene rubber for low-temperature performance tends to deteriorate wet grip, and adding resins for wet grip performance can compromise low-temperature performance.
Innovation Solution
A rubber composition comprising 40 mass % or more of butadiene rubber, 60 to 200 parts of silica, and 20 to 60 parts 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 enhancing wet grip performance.
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 uses a composite material system combining butadiene rubber (for low-temperature performance) with a specific resin component (containing 5 mass% or more of β-pinene unit) and silica filler. This composite structure allows the butadiene rubber to maintain low-temperature flexibility while the resin-silica network provides wet grip performance, resolving the contradiction between the two performance requirements.
Solution Approach 2:
The patent changes the chemical composition parameters by specifying a resin with at least 5 mass% β-pinene unit content and controlling the resin-to-silica ratio. This parameter optimization allows the system to achieve both low-temperature performance (from butadiene rubber) and wet grip performance (from the resin-silica interaction) simultaneously.
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 optimizes the resin composition by specifying at least 5 mass% β-pinene unit content and controlling the resin amount relative to silica (0.05 to 0.5 mass% per 1 mass% silica). This parameter control ensures the resin improves wet grip through silica interaction while maintaining compatibility with butadiene rubber's low-temperature properties.
Solution Approach 2:
The resin acts as an intermediary that bridges silica filler and butadiene rubber matrix. The β-pinene-containing resin interacts with silica to improve wet grip while its molecular structure remains compatible with butadiene rubber, preventing deterioration of low-temperature 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
This composition effectively achieves both low-temperature and wet grip performance, making it suitable for all-season tires that operate on both wet and snowy roads.
Implementation Method 1
a rubber component containing 40 mass % or more of a butadiene rubber combined with a β-pinene resin having a β-pinene unit content of 40 mass % or more
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 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.