Spherical Silica Nanoparticles in Rubber Compositions
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Solution Overview
Problem
Current tire compositions face challenges in achieving a balance between reduced rolling resistance and improved wear resistance while maintaining good grip on both dry and wet surfaces, with existing solutions such as using highly dispersible precipitated silica not fully addressing these requirements.
Innovation Solution
Incorporating silica in the form of essentially spherical nanoparticles with a BET specific surface area ranging from 30 m²/g to 250 m²/g as a reinforcing filler in rubber compositions, which enhances dispersion and reinforcement properties, allowing for improved rolling resistance and wear resistance without compromising grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If highly dispersible precipitated silica with BET specific surface area between 100 and 250 m²/g is used as reinforcing filler, then rolling resistance is reduced and grip properties are improved, but wear resistance is penalized
Solution Approach 1:
The patent changes the particle morphology parameter of silica from irregular precipitated silica to essentially spherical particles, while controlling the BET specific surface area to be between 30 and 150 m²/g. This parameter change optimizes both the dispersion in the rubber matrix and the reinforcement effectiveness, achieving improved rolling resistance, wear resistance, and grip properties simultaneously
Solution Approach 2:
The patent uses a composite filler system comprising essentially spherical silica particles combined with a coupling agent (such as silane) to create an optimized reinforcement system. The coupling agent forms a bridge between the silica particles and the rubber matrix, enhancing the overall composite performance for wear resistance while maintaining the low rolling resistance benefits of spherical silica
2Reliability
If high volume fractions of reinforcing fillers and diluents are used to improve grip properties, then grip on wet surfaces is improved, but rolling resistance increases
Solution Approach 1:
The patent changes the particle shape parameter to essentially spherical morphology, which reduces particle-particle friction and improves flow characteristics. This allows for better dispersion at lower filler volume fractions, achieving good grip properties without the need for high filler loading that would increase rolling resistance
Solution Approach 2:
The patent optimizes the local distribution and interaction of spherical silica particles with the rubber matrix through controlled surface properties and coupling agent selection. This creates localized reinforcement zones that provide grip without requiring high overall filler content, thus avoiding excessive rolling resistance
3Use of energy by moving object
If conventional silica with high BET specific surface area is used to reduce rolling resistance, then rolling resistance is reduced, but the composition becomes difficult to process due to scorching
Solution Approach 1:
The patent changes the particle morphology to essentially spherical shape with controlled BET specific surface area (30-150 m²/g), which reduces the total surface area compared to highly dispersed irregular silica. This parameter change reduces the total number of active sites that can cause premature vulcanization, improving processability while maintaining rolling resistance benefits
Solution Approach 2:
The patent converts the potentially harmful effect of high surface area (which causes scorching) into a benefit by using spherical morphology. The spherical shape provides lower packing density and reduced inter-particle contact compared to irregular particles with similar surface area, thereby reducing premature vulcanization while maintaining the rolling resistance advantages of high surface area silica
Data Source
Figure 1
AI summary
The present invention relates to a rubber composition based on one or more diene elastomer(s), on at least one reinforcing filler, on at least one coupling agent, on at least one chemical crosslinking system, wherein the reinforcing filler comprises silica in the form of essentially spherical nanoparticles, the specific surface area of this silica ranging from 30 m2/g to 250 m2/g. The invention relates to a process for producing such a composition and also to semi-finished or finished articles comprising at least one such composition.