Run-flat Tire Sidewall Composition for Durability and Comfort
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Solution Overview
Problem
Run flat tires face challenges in achieving improved durability without compromising ride comfort, as existing rubber compositions either soften the sidewall reinforcing layer or impair vulcanization, leading to increased deflection and heat generation.
Innovation Solution
A rubber composition for run flat tires is developed, incorporating a low-molecular weight conjugated diene-based polymer with a weight average molecular weight of 10,000 to 40,000, a vulcanization accelerator in a specific ratio, and sulfur, which enhances the sidewall reinforcing layer's durability and elasticity while maintaining ride comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the modulus of elasticity is increased or loss tangent is reduced to suppress heat generation, then run flat durability is improved, but ride comfort deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular weight of the conjugated diene-based polymer (10,000 to 40,000) and the mass ratio of vulcanization accelerator to polymer (1 to 3.5). This specific parameter control enables the sidewall reinforcing layer to achieve both high run flat durability and acceptable ride comfort by optimizing the balance between heat resistance and elasticity
Solution Approach 2:
The patent uses composite materials by combining the conjugated diene-based polymer with specific vulcanization accelerators in controlled ratios. This composite approach creates a synergistic effect where the polymer provides heat resistance while the accelerator system maintains elasticity, resolving the contradiction between run flat durability and ride comfort
2Ease of operation
If conventional rubber compositions are used to maintain elasticity, then ride comfort is preserved, but run flat durability is insufficient due to excessive heat generation
Solution Approach 1:
The patent changes the critical parameter of polymer molecular weight to a specific range (10,000 to 40,000) and controls the vulcanization accelerator ratio (1 to 3.5). This parameter optimization allows the material to simultaneously achieve low heat generation for durability and sufficient elasticity for comfort
3Ease of operation
If the sidewall reinforcing layer is softened to improve elasticity, then ride comfort is improved, but run flat durability decreases due to increased deflection
Solution Approach 1:
The patent applies parameter changes by controlling the molecular weight (10,000 to 40,000) and accelerator ratio (1 to 3.5) to achieve an optimal balance point where the sidewall has sufficient elasticity for comfort while maintaining enough rigidity to prevent excessive deflection and ensure run flat durability
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 effectively improves run flat durability without impairing ride comfort by controlling the content ratio of the vulcanization accelerator to the low-molecular weight conjugated diene-based polymer, promoting crosslinking and network structure strengthening in the sidewall reinforcing layer.
Implementation Method 1
a vulcanization accelerator, with a mass ratio of the content of the vulcanization accelerator to the content of the low-molecular weight conjugated diene-based polymer (vulcanization accelerator/low-molecular weight conjugated diene-based polymer) being 1 to 3.5
Data Source
Figure 1
AI summary
The present invention relates to a rubber composition for run flat tires, containing a rubber component; a low-molecular weight conjugated diene-based polymer having a weight average molecular weight of 10,000 to 40,000 as expressed in terms of polystyrene in an amount of 1 to 10 parts by mass based on 100 parts by mass of the rubber component; and a vulcanization accelerator, with a ratio of the content of the vulcanization accelerator to the content of the low-molecular weight conjugated diene-based polymer (vulcanization accelerator/low-molecular weight conjugated diene-based polymer) being 1 to 3.5, from which a run flat tire with improved run flat durability without impairing the ride comfort is obtained. The run flat tire includes a sidewall section having a side reinforcing rubber layer formed from the rubber composition for run flat tires, a tread, a carcass, a bead core, and a bead filler.