Tire Tread Rubber Composition to Suppress Long-Term Hardening
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Solution Overview
Problem
The hardening phenomenon in the tread part of tires over time leads to a decrease in tire performance, including steering stability and wet grip performance.
Innovation Solution
The tire design incorporates specific thickness ratios for the cap rubber layer, acetone extraction amounts, and ash content relationships to control plasticizer migration, thereby suppressing hardening and enhancing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tread part uses conventional rubber layer composition and thickness, then the tire can be manufactured with standard performance, but the tread part hardens over time causing performance degradation
Solution Approach 1:
The patent applies local quality by creating distinct rubber layers with different compositions and properties. The cap rubber layer contains specific plasticizers and antioxidants to prevent hardening, while the base rubber layer has different characteristics. Each layer is optimized for its specific function, with the cap layer specifically designed to maintain flexibility and prevent hardening over time through localized chemical composition control.
Solution Approach 2:
The patent uses composite materials by combining multiple rubber layers with different compositions. The tread part consists of a cap rubber layer and a base rubber layer, each with specific plasticizer contents, antioxidant contents, and physical properties. This composite structure allows the overall tread to resist hardening while maintaining good abrasion resistance and flexibility through the synergistic effects of different material compositions.
2Ease of operation
If the cap rubber layer thickness is increased to improve wet grip and steering stability, then handling performance improves, but the overall tread part may become too rigid
Solution Approach 1:
The patent applies local quality by making the cap rubber layer (which contacts the road surface) have specific plasticizer content (5-20 parts by mass per 100 parts by mass of rubber) and antioxidant content to provide enhanced wet grip and steering stability. The base rubber layer has different composition characteristics. This localized optimization allows the cap layer to provide improved handling while the overall structure maintains flexibility through the multi-layer composite design.
3Reliability
If plasticizer content is increased to prevent hardening, then the tread remains flexible longer, but the acetone extraction amount increases which may affect other performance characteristics
Solution Approach 1:
The patent applies parameter changes by precisely controlling the plasticizer content within specific ranges (5-20 parts by mass per 100 parts by mass of rubber in the cap layer) and antioxidant content (0.5-5 parts by mass per 100 parts by mass of rubber). These parameter optimizations ensure sufficient flexibility and resistance to hardening while keeping acetone extraction amounts within acceptable limits. The balanced composition prevents excessive plasticizer migration and maintains performance stability over time.
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 maintains improved steering stability and wet grip performance by controlling the hardening phenomenon through precise layer thickness and composition adjustments.
Implementation Method 1
a concentration gradient of a plasticizer between a tread part and a tire internal member causes the plasticizer to migrate from a tread rubber to an internal rubber
Data Source
AI summary
Provided is a tire comprising a tread part having at least one rubber layer and a breaker, wherein a thickness of a cap rubber layer constituting a tread surface relative to a total thickness of the tread part is 20% or more, wherein an average value of acetone extraction amounts of a tread rubber constituting the tread part is 12.0% by mass or less, wherein a difference between the average value of the acetone extraction amounts of the tread rubber and an acetone extraction amount of a breaker topping rubber is 7.0% by mass or less, and wherein an average value of ash contents of the tread rubber is 7.5% by mass or more.