Run-Flat Tire Sidewall Rubber Composition for Low Heat Durability
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Solution Overview
Problem
Existing run-flat tires face challenges in enhancing durability while maintaining low rolling resistance, particularly due to limitations in the side-reinforcing rubber composition.
Innovation Solution
A side-reinforcing rubber for run-flat tires is developed, comprising a vulcanized rubber formed from a rubber composition containing dienic rubber, a vulcanizing agent, and carbon black with specific properties, including a polysulfide bond ratio of 40% or less and the use of modified butadiene rubber and thiuram compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a side-reinforcing layer is formed using conventional rubber composition to enhance run-flat durability, then the tire can maintain structural integrity under load, but the rolling resistance increases and heat generation rises
Solution Approach 1:
The patent applies parameter changes by carefully controlling the polysulfide bond ratio (Sx bond ratio) to be 40% or less, and by specifying the carbon black properties (DBP oil absorption of 120 mL/100 g or more, specific surface area of 20 to 80 m²/g). These parameter optimizations reduce hysteresis loss and heat generation while maintaining the reinforcing effect needed for run-flat durability.
Solution Approach 2:
The patent uses composite materials by combining dienic rubber with specifically selected carbon black having high DBP oil absorption and controlled specific surface area. This composite approach creates a rubber composition that achieves both mechanical reinforcement for durability and low hysteresis for reduced rolling resistance.
2Strength
If the side-reinforcing rubber is made stiffer to improve run-flat performance, then the tire can support higher loads, but heat generation increases and antiaging performance deteriorates
Solution Approach 1:
The patent controls the polysulfide bond ratio (Sx bond ratio) to be 40% or less, which prevents excessive crosslinking that would cause heat buildup. Simultaneously, it specifies carbon black with DBP oil absorption of 120 mL/100 g or more and specific surface area of 20 to 80 m²/g, achieving the right balance between stiffness and heat resistance for improved antiaging performance.
3Strength
If carbon black with high surface area is used to enhance reinforcement, then the tire strength increases, but heat generation increases and rolling resistance worsens
Solution Approach 1:
The patent optimizes carbon black parameters by specifying DBP oil absorption of 120 mL/100 g or more and specific surface area of 20 to 80 m²/g. This parameter control ensures sufficient reinforcement while limiting excessive surface area that would cause high hysteresis and heat generation, thereby reducing rolling resistance.
4Loss of energy
If the rubber composition is optimized for low rolling resistance, then energy efficiency improves, but run-flat durability decreases
Solution Approach 1:
The patent creates a composite rubber composition combining dienic rubber with carbon black having high DBP oil absorption (≥120 mL/100 g) and controlled specific surface area (20 to 80 m²/g). This composite provides both low hysteresis for reduced rolling resistance and sufficient reinforcement for run-flat durability.
Solution Approach 2:
The patent controls the polysulfide bond ratio to be 40% or less while optimizing carbon black properties, achieving a balance that delivers both low rolling resistance through reduced heat generation and adequate run-flat durability through maintained structural integrity.
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 solution significantly improves the durability life of run-flat tires by enhancing heat-resistant antiaging performance and maintaining low-heat generation properties, thereby supporting the tire's structure under high-compression and high-temperature conditions.
Implementation Method 1
a carbon black having a dibutyl phthalate oil absorption of 120 mL/100 g or more, and has a specific surface area according to a nitrogen adsorption method of 20 to 80 m2
Implementation Method 2
a carbon black having a dibutyl phthalate oil absorption of 120 mL/100 g or more, and has a specific surface area according to a nitrogen adsorption method of 20 to 80 m2
Implementation Method 3
a vulcanized rubber which is formed from a rubber composition containing a rubber component containing a dienic rubber, a vulcanizing agent
Data Source
Figure 1
AI summary
The side-reinforcing rubber for run-flat tires of the present invention is a side-reinforcing rubber for run-flat tires, including a vulcanized rubber which is formed of a rubber composition containing a rubber component containing a dienic rubber, a vulcanizing agent, and a carbon black having a dibutyl phthalate oil absorption of 120 mL/100 g or more, and has a specific surface area according to a nitrogen adsorption method of 20 to 80 m2/g, with a ratio of an Sx bond (where x is 3 or more) to all sulfide bonds in the side-reinforcing rubber for run-flat tires being 40% or less. The side-reinforcing rubber for run-flat tires is excellent in durability life.