Silica-Filled Rubber Tread Composition with Silane Coupling Agent
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Solution Overview
Problem
Conventional rubber compositions for tire treads face challenges in achieving low rolling resistance and wet performance while maintaining extrudability, due to poor silica dispersibility and issues with viscosity and scorching.
Innovation Solution
A rubber composition is developed with 60-130 parts of silica per 100 parts of diene rubber, compounded with a silane coupling agent having a mercapto group and Si-O bond, and diethylene glycol, which improves silica dispersibility and reduces viscosity, thereby enhancing low rolling resistance and wet performance while maintaining extrudability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silica is compounded in rubber composition to improve low rolling resistance and wet performance, then dynamic viscoelastic characteristics are improved, but silica particles aggregate through hydrogen bonds and dispersion becomes poor
Solution Approach 1:
A silane coupling agent with mercapto groups is introduced as an intermediary substance between silica particles and rubber matrix. The silane coupling agent contains both silanol groups that bond with silica and mercapto groups that interact with rubber, preventing silica aggregation and improving dispersion. This mediator resolves the contradiction by enabling silica to maintain both low rolling resistance and good dispersibility.
Solution Approach 2:
The invention creates a composite system combining silica, silane coupling agent, and rubber in specific proportions. The silane coupling agent forms a bridging layer between silica particles and rubber matrix, creating a stable composite structure where silica remains dispersed while providing the desired viscoelastic properties for wet performance.
2Stability of the object's composition
If a mercapto group-containing silane coupling agent is compounded to improve silica dispersibility, then rolling resistance and wet performance are improved, but viscosity increases and extrudability becomes poor
Solution Approach 1:
The invention optimizes the concentration of silane coupling agent and adjusts processing parameters such as mixing temperature and time. By controlling these parameters, the silane coupling agent effectively disperses silica without causing excessive viscosity increase. The specific ratio of silane coupling agent to silica is optimized to maintain extrudability while achieving good dispersion.
3Loss of energy
If silica content is increased to enhance low rolling resistance, then fuel consumption performance is improved, but scorch (premature curing) readily occurs
Solution Approach 1:
The silane coupling agent acts as a protective intermediary between silica and rubber, controlling the reactivity of the system. It prevents premature cross-linking reactions by regulating how silica interacts with rubber, thereby suppressing scorch while allowing the silica to provide low rolling resistance benefits.
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 improved silica dispersibility, reduced viscosity, and suppressed scorching, resulting in enhanced low rolling resistance and wet performance, along with improved extrudability and productivity in tire production.
Implementation Method 1
a silane coupling agent having a mercapto group and an Si-O bond is compounded in an amount from 4 to 15% by weight of the silica content
Implementation Method 2
the particles of silica tend to aggregate together through hydrogen bonds of silanol groups, which are the surface functional group thereof
Implementation Method 3
viscosity of the rubber composition can be improved, scorch (premature curing) can be suppressed and extrudability can be maintained or improved because diethylene glycol is compounded in the rubber composition
Implementation Method 4
dynamic viscoelastic characteristics of the tread rubber such as loss tangent (tanĪ“) have been improved
Data Source
AI summary
Problem: To provide a rubber composition for use in tire treads that enhances low rolling resistance and wet performance to conventional levels or above while maintaining and enhancing extrudability. Solution: A rubber composition for use in tire treads comprising from 60 to 130 parts by weight of silica per 100 parts by weight of diene rubber containing not less than 50% by weight of hydroxyl group-containing modified styrene butadiene rubber, in which the weight ratio of oil to filler containing the silica is not greater than 0.25, and a silane coupling agent having a mercapto group and an Si-O bond is compounded in an amount from 4 to 15% by weight of the silica content, and diethylene glycol is compounded in an amount from 1 to 6% by weight of the silica content.