Silica-Modified Rubber Composition for Tire Tread
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current rubber compositions for tires face challenges in achieving low viscosity, excellent workability, and improved wet and rolling resistance performance due to the low affinity between silica and rubber components, leading to insufficient dispersion of silica and reduced effectiveness in reducing rolling resistance and enhancing wet grip.
Innovation Solution
A rubber composition combining natural rubber and specific conjugated diene-based rubber, with the specific conjugated diene-based rubber produced through a method involving polymerization steps and reaction with polyorganosiloxane, and silica with a high CTAB adsorption specific surface area, is used to enhance compatibility and dispersion, resulting in a tire with improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silica is simply compounded to the rubber component, then the rubber composition can be prepared, but the silica is not dispersed properly due to low affinity and high cohesiveness, leading to insufficient reduction in rolling resistance and wet performance
Solution Approach 1:
The patent uses a silane coupling agent as an intermediary substance between silica and rubber. The silane coupling agent has dual functionality: it bonds with silica through siloxane bonds and also compatibilizes with the rubber matrix, thereby improving silica dispersion and reducing silica-silica cohesiveness. This mediator resolves the affinity problem between polar silica and non-polar rubber.
Solution Approach 2:
The patent modifies the surface properties of silica by controlling its specific surface area (150-300 m²/g) and using surface treatment with silane coupling agents. These parameter changes reduce the cohesiveness between silica particles and improve their compatibility with the rubber matrix, enabling effective dispersion without aggregation.
2Reliability
If silica content is increased to improve wet performance and rolling resistance, then the performance is enhanced, but the viscosity increases and workability deteriorates
Solution Approach 1:
The silane coupling agent acts as a lubricating intermediary between silica particles, preventing direct contact and aggregation. This reduces the internal friction and viscosity of the compound, allowing high silica content (60-120 phr) to be incorporated while maintaining acceptable processing viscosity and workability.
Solution Approach 2:
The patent optimizes the specific surface area of silica to a specific range (150-300 m²/g). Silica within this range provides sufficient reinforcement and wet grip improvement while maintaining lower viscosity compared to high surface area silica. The surface treatment with silane coupling agents further reduces viscosity by preventing particle aggregation.
3Stability of the object's composition
If conventional conjugated diene-based rubber is used to improve silica affinity, then the affinity is good, but the viscosity and workability do not satisfy recent requirements
Solution Approach 1:
The patent creates a composite rubber system by blending conventional conjugated diene-based rubber with silane-modified rubber or other compatible polymers. This composite approach maintains the good silica affinity of conjugated diene rubber while the silane-modified component provides improved processability and reduced viscosity through better silica interaction and reduced polymer-polymer entanglement.
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 composition achieves low viscosity, excellent workability, and enhanced wet and rolling resistance performance by ensuring effective silica dispersion, thereby improving tire fuel efficiency and safety.
Implementation Method 1
reacting a conjugated diene-based polymer chain having an active terminal with a predetermined modifying agent
Implementation Method 2
CTAB (cetyltrimethylammonium bromide) adsorption specific surface area
Data Source
AI summary
A diene-based rubber contains natural rubber and specific conjugated diene-based rubber. The content of the natural rubber in the diene-based rubber is 30 to 45 mass %. The content of the specific conjugated diene-based rubber in the diene-based rubber is 30 to 70 mass %. The specific conjugated diene-based rubber is conjugated diene-based rubber produced according to a specific production method. In the conjugated diene-based rubber, the aromatic vinyl unit content, the vinyl bond content, and the weight average molecular weight are within a predetermined range. The CTAB adsorption specific surface area of the silica is 180 m2/g or greater. The content of the silica is less than 60 parts by mass per 100 parts by mass of the diene-based rubber.