Polysiloxane Silane Coupling Agent for Tire Tread Rubber
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Solution Overview
Problem
Rubber compositions for tire treads with silica face challenges in achieving high silica dispersibility while maintaining excellent processability, as existing silane coupling agents either improve dispersibility at the cost of processability or vice versa.
Innovation Solution
A rubber composition combining diene rubber, silica, and a specific polysiloxane silane coupling agent with a sulfide group and mercapto group, represented by a specific average composition formula, is used, which balances silica dispersibility and processability by regulating the generation of thiyl radicals and ensuring compatibility with silica.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a silane coupling agent with mercapto group is used to improve silica dispersibility, then silica dispersibility is improved, but Mooney viscosity increases and processability deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters of the silane coupling agent by introducing a polysiloxane backbone with specific silane groups. This structural modification allows the coupling agent to maintain silica dispersibility while controlling Mooney viscosity through the flexible polysiloxane chain that prevents excessive crosslinking during mixing
Solution Approach 2:
The patent creates a composite silane coupling agent system combining polysiloxane backbone with reactive silane groups (such as triethoxysilylpropyl). This composite structure provides both the dispersibility enhancement from the silane groups and the processability control from the polysiloxane matrix, resolving the contradiction between silica dispersion and processing ease
2Reliability
If silica is used as reinforcing filler to reduce rolling resistance and improve wet road stability, then rolling resistance and wet stability are improved, but silica particles agglomerate and adversely affect wear resistance and mechanical characteristics
Solution Approach 1:
The polysiloxane silane coupling agent acts as an intermediary between silica particles and the rubber matrix. The silane groups bond to silica surface hydroxyl groups while the polysiloxane chains interact with the rubber, creating a bridge that prevents silica agglomeration and ensures uniform distribution, thereby maintaining both wet stability and wear resistance
Solution Approach 2:
The patent applies local quality modification by treating only the surface of silica particles with the silane coupling agent. The silane groups concentrate at the silica surface to prevent agglomeration, while the bulk silica maintains its reinforcing properties, achieving both improved dispersion and preserved mechanical characteristics
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 high silica dispersibility and excellent processability, resulting in improved tire performance with enhanced wet traction, rolling resistance, and wear resistance.
Implementation Method 1
the silane coupling agent is a polysiloxane represented by an average composition formula of formula (1) below
Implementation Method 2
the silane coupling agent is a polysiloxane represented by an average composition formula of formula (1) below
Implementation Method 3
regulating the generation of thiyl radicals and ensuring compatibility with silica
Data Source
AI summary
The problem of the present invention is to provide a rubber composition for tire treads having high silica dispersibility while also having excellent processability. The rubber composition for tire treads of the present invention contains a diene rubber, silica and a silane coupling agent, wherein the silane coupling agent is a polysiloxane represented by a specific average composition formula, the silica content is from 5 to 200 parts by mass per 100 parts by mass of the diene rubber, and the silane coupling agent content is from 1 to 20 mass% relative to the silica content.