Tread Rubber Composition for Wet Grip After Heat Aging
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Solution Overview
Problem
Tread rubber compositions with silica for improved wet grip performance face challenges in maintaining grip when thermally damaged, as the oil used for processability migrates, reducing acetone extractable content and degrading performance over time.
Innovation Solution
A tread rubber composition with specific acetone extractable content ratios before and after heat aging, incorporating silica and either a liquid polymer or resin to maintain compatibility and prevent migration, ensuring high wet grip performance even after thermal damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silica is incorporated to improve wet grip performance, then wet grip performance is improved, but processability is reduced
Solution Approach 1:
An organic compound containing a silane coupling agent is introduced as an intermediary substance between silica and the rubber matrix. This coupling agent modifies the silica surface to enhance compatibility with the rubber, improving dispersion and adhesion without requiring excessive oil, thus maintaining both wet grip performance and processability
Solution Approach 2:
The patent creates a composite material system combining silica, organic compound with silane coupling agent, and rubber. This composite approach allows the synergistic effects of silica (for wet grip) and the organic coupling agent (for compatibility and processability), resolving the contradiction between performance and manufacturability
2Ease of manufacture
If oil is used to secure processability, then processability is improved, but wet grip performance degrades when thermally damaged
Solution Approach 1:
The patent changes the chemical parameters of the plasticizing component by using an organic compound with silane coupling agent instead of conventional oil. This parameter change transforms the substance from a migratory oil to a chemically bonded coupling agent that remains stable under thermal conditions, maintaining wet grip performance after thermal damage while still providing necessary processability
Solution Approach 2:
The patent replaces the conventional approach of using large amounts of oil (which degrades over time) with a small amount of effective silane coupling agent compound. This substitution uses a more stable, long-lasting substance that maintains performance over time, effectively replacing the 'short-living' oil-based approach
3Stability of the object's composition
If acetone extractable content decreases due to oil migration, then composition stability is improved, but wet grip performance is degraded
Solution Approach 1:
The silane coupling agent acts as an intermediary that chemically bonds silica to the rubber matrix, creating a stable composite structure. This bonding prevents the migration that would otherwise occur with oil-based plasticizers, maintaining both composition stability and wet grip performance simultaneously
Solution Approach 2:
The patent applies local quality modification by treating the silica surface with silane coupling agent. This creates a localized region of enhanced compatibility and bonding at the silica-rubber interface, preventing migration in that critical area while maintaining overall composition stability and performance
Data Source
AI summary
Provided are a tread rubber composition and a pneumatic tire, which exhibit excellent wet grip performance when thermally damaged. A tread rubber composition having acetone extractable contents before and after heat aging (denoted by “AEf” and “AEo”, respectively) that satisfy the following relationships 1) and 2):1) AEf≥16.0%;2) AEo/AEf×100≥95%.