Silica-Reinforced Tire Rubber Composition with Silane Coupling Agent
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Solution Overview
Problem
Conventional rubber compositions for tires face challenges in achieving low rolling resistance, dry performance, and wet performance simultaneously while maintaining good workability, due to poor silica dispersion and increased viscosity when silica and reinforcing fillers are increased.
Innovation Solution
A rubber composition comprising 90-150 parts of silica blended with a diene rubber containing at least 25% modified conjugated diene polymer rubber with a siloxane structure and a silane coupling agent, along with alkyltriethoxysilane, which enhances silica dispersion and affinity, reducing rolling resistance and improving dry and wet performance while maintaining workability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the compounded amount of silica and reinforcing fillers is increased to improve low rolling resistance and wet performance, then heat build-up is suppressed and fuel consumption performance is improved, but tire rigidity and dry grip performance are reduced
Solution Approach 1:
A silane coupling agent is introduced as an intermediary substance between silica and diene rubber. The silane coupling agent forms chemical bonds with both silica and rubber, creating a bridging interface that enhances the reinforcing effect of silica while maintaining good dispersion. This allows achieving low rolling resistance with moderate silica amounts without sacrificing tire rigidity.
Solution Approach 2:
The invention optimizes the compounding amounts of silica (90-150 parts per 100 parts diene rubber) and silane coupling agent (3-20 mass% relative to silica) to achieve the best balance between rolling resistance and rigidity. By precisely controlling these parameters, the patent achieves both low energy loss and sufficient strength.
2Loss of energy
If the compounded amount of silica is increased to achieve low rolling resistance and wet grip performance, then fuel efficiency is improved, but silica dispersion deteriorates due to poor affinity with diene rubbers
Solution Approach 1:
The silane coupling agent serves as a mediator that improves silica dispersion by forming chemical bridges between silica particles and diene rubber molecules. This intermediary substance overcomes the poor natural affinity between silica and rubber, enabling uniform distribution of high amounts of silica (90-150 parts) without aggregation.
Solution Approach 2:
The invention creates a composite structure where silica, silane coupling agent, and diene rubber form an integrated system. The silane-modified silica-rubber composite achieves superior dispersion and interfacial bonding, allowing high silica content while maintaining compositional stability and uniform distribution.
3Stability of the object's composition
If the compounded amount of terminal-modified solution polymerization styrene-butadiene rubber is increased to improve silica dispersibility, then wet performance is enhanced, but the viscosity of the rubber composition increases and workability deteriorates
Solution Approach 1:
The patent optimizes the content of terminal-modified SBR (at least 25 mass% of total diene rubber) to achieve sufficient silica dispersibility while controlling viscosity. By setting the minimum threshold rather than using excessive amounts, the invention maintains good workability while ensuring adequate dispersion improvement.
Solution Approach 2:
The silane coupling agent acts as an additional intermediary that reduces the need for excessive terminal-modified SBR. This alternative dispersibility enhancement method allows using moderate amounts of modified rubber while achieving good silica distribution, thereby avoiding excessive viscosity increase.
4Loss of energy
If various silane coupling agents are used in combination to increase silica compounded amount, then both low rolling resistance and wet grip performance are achieved, but the viscosity of the rubber composition increases
Solution Approach 1:
The patent specifies precise compounding ranges: silica at 90-150 parts per 100 parts diene rubber and silane coupling agent at 3-20 mass% relative to silica. These optimized parameters achieve low rolling resistance while controlling viscosity to maintain acceptable workability, avoiding the excessive viscosity caused by uncontrolled high silica compounding.
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 significantly reduces rolling resistance, enhances dry and wet performance, and maintains excellent workability by optimizing silica dispersion and reinforcing properties, surpassing conventional tire performance levels.
Implementation Method 1
a silane coupling agent is blended in an amount of 3 to 20 mass % relative to the amount of silica described above
Implementation Method 2
an alkyltriethoxysilane having an alkyl group with 7 to 20 carbons is blended in an amount of 0.1 to 20 mass % relative to the amount of silica described above
Implementation Method 3
dynamic viscoelastic characteristics of the tread rubber such as loss tangent (tan δ) and the like have been improved, heat build-up has been suppressed, rolling resistance reduced
Data Source
AI summary
The present technology provides a rubber composition for a tire which improves the low rolling resistance, dry performance, wet performance, and workability so as to surpass conventional levels. In the rubber composition for a tire according to the present technology, silica is blended into the composition in an amount of 90 to 150 parts by mass relative to 100 parts by mass of a diene rubber containing at least 25 mass % of a modified conjugated diene polymer rubber having a siloxane structure in at least some of the terminal-modifying groups. A silane coupling agent is blended into the composition in an amount of 3 to 20 mass % relative to the amount of silica, and an alkyltriethoxysilane having an alkyl group with 7 to 20 carbons is blended in an amount of 0.1 to 20 mass % relative to the amount of silica.