Tread Rubber Phase Separation for Wear and Rolling Resistance Balance
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Solution Overview
Problem
Current rubber compositions for tires face challenges in achieving a balance between wet performance, wear resistance, low rolling resistance, and breaking resistance, as conventional inorganic fillers like silica improve wet performance but increase energy loss, making it difficult to reduce rolling resistance while maintaining wear resistance.
Innovation Solution
A rubber composition comprising modified conjugated diene-based polymers with specific molecular weights and branching factors, separated into incompatible polymer phases with a filler distribution that satisfies a particular concentration and aggregate area formula, enhancing the balance of wet performance, wear resistance, and low rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic fillers like silica are used to improve wet performance, then wet gripping performance is improved, but rolling resistance increases due to energy loss
Solution Approach 1:
The patent changes the molecular weight parameters of the conjugated diene-based polymer, specifically setting weight-average molecular weight to 20×10^4 to 300×10^4 and including high molecular weight components (200×10^4 to 500×10^4) at specific ratios. This parameter optimization reduces energy loss while maintaining wet gripping performance by improving the polymer-filler interaction efficiency.
Solution Approach 2:
The patent creates a composite system by combining modified conjugated diene-based polymers with specific molecular weight characteristics and inorganic fillers. The composite achieves synergistic effects where the optimized polymer structure reduces the negative impact of fillers on rolling resistance while maintaining their beneficial effect on wet performance.
2Loss of energy
If conventional rubber compositions are formulated to achieve low rolling resistance, then energy loss is reduced, but wear resistance deteriorates
Solution Approach 1:
The patent optimizes the molecular weight distribution parameters of the conjugated diene-based polymer, specifically controlling the weight-average molecular weight (20×10^4 to 300×10^4) and the ratio of high molecular weight components. This parameter control enhances both wear resistance and maintains low rolling resistance by improving the polymer's mechanical strength while preserving energy efficiency.
Solution Approach 2:
The patent introduces local quality by creating specific molecular weight distribution zones within the polymer structure, including high molecular weight components (200×10^4 to 500×10^4) at controlled ratios (0.25 to 30% by mass). These localized high molecular weight regions provide enhanced wear resistance while the overall molecular weight distribution maintains low rolling resistance characteristics.
3Loss of energy
If rubber composition is optimized for wet performance and low rolling resistance, then wet gripping and energy efficiency are improved, but breaking resistance deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameters of the conjugated diene-based polymer, setting weight-average molecular weight to 20×10^4 to 300×10^4 and controlling the content of high molecular weight components (200×10^4 to 500×10^4) at 0.25 to 30% by mass. This parameter optimization simultaneously improves wet gripping performance, reduces rolling resistance, and enhances breaking resistance by providing sufficient molecular chain length and entanglement.
Solution Approach 2:
The patent formulates a composite rubber composition combining modified conjugated diene-based polymers with optimized molecular weight characteristics and inorganic fillers. This composite structure achieves a balanced improvement in wet performance, rolling resistance, and breaking resistance through synergistic interactions between the polymer matrix and filler components.
Data Source
AI summary
To provide a rubber composition in which wet performance, wear resistance, low rolling resistance, and breaking resistance are highly balanced. A rubber composition comprising a rubber component comprising at least three polymers and a filler, wherein the rubber component is separated into at least two polymer phases: a polymer phase (1) with the highest tan δ peak temperature; and a polymer phase (2) with the lowest peak temperature; the polymer phases (1) and (2) are incompatible with each other; the polymer phase (1) at least comprises the modified conjugated diene-based polymers (A1) and (A2), and the filler; the modified conjugated diene-based polymer (A1) has a particular weight-average molecular weight and a particular contracting factor (g′); and when a filler concentration and an average aggregate area of the filler in the polymer phase (1) are defined as X and Y, respectively, an formula (1): Y<4.8X+1200 is satisfied.