Tire Rubber Composition Balancing Elastic Modulus and Low Tanδ
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rubber compositions for tires struggle to achieve a high elastic modulus and low tanδ simultaneously, leading to issues such as increased viscosity, worsened workability, and reduced abrasion and fracture resistance, while attempts to improve low-heat-generation properties often compromise these characteristics.
Innovation Solution
Incorporation of a compound with an amidine structure and a functional group reactive with diene-based rubber, such as bis[2-(1H-benzimidazol-1-yl)ethyl] disulfane, enhances chemical interaction between the filler and rubber, improving reinforcing performance and maintaining high elastic modulus and low tanδ, while preventing gelation and increasing scorch time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the amount of filler such as carbon black is increased to improve the elastic modulus, then the elastic modulus is improved, but the viscosity of the unvulcanized rubber composition increases and workability during kneading worsens
Solution Approach 1:
The patent introduces a silane coupling agent as an intermediary substance that mediates between the filler (carbon black) and the rubber matrix. This coupling agent creates a bridge that enhances the elastic modulus by improving filler-rubber interaction without requiring excessive filler loading, thereby maintaining workability during kneading.
Solution Approach 2:
The patent modifies the chemical parameters of the rubber composition by introducing specific silane-based compounds that react with both the filler surface and the rubber matrix. This chemical parameter change enables effective stress transfer at lower filler concentrations, resolving the contradiction between elastic modulus improvement and workability maintenance.
2Strength
If the amount of filler such as carbon black is increased to improve the elastic modulus, then the elastic modulus is improved, but tanδ of the vulcanized rubber composition increases
Solution Approach 1:
The silane coupling agent acts as an intermediary that reduces energy loss by creating a more efficient stress transfer interface between filler and rubber. This intermediary layer prevents excessive hysteresis heating that would otherwise occur with high filler loading, thereby lowering tanδ while maintaining elastic modulus.
Solution Approach 2:
The patent creates a composite material system where silane-modified filler particles are dispersed in the rubber matrix. This composite structure optimizes the filler-rubber interface, enabling simultaneous achievement of high elastic modulus and low tanδ through synergistic interactions between the components.
3Loss of energy
If the particle size of carbon black is increased or the amount of carbon black is decreased to lower tanδ, then tanδ is lowered, but the abrasion resistance and fracture resistance are lowered
Solution Approach 1:
The silane coupling agent serves as a mediator that compensates for the reduced reinforcement effect of lower carbon black loading. By enhancing the interfacial adhesion between filler and rubber, the coupling agent maintains abrasion and fracture resistance even when carbon black content is reduced to lower tanδ.
4Loss of energy
If carbon black is substituted with silica and a silane coupling agent is used to reduce tanδ, then tanδ is reduced, but the abrasion resistance and fracture resistance are lowered and durability is worsened
Solution Approach 1:
The patent optimizes the silane coupling agent structure and dosage parameters to achieve better performance than conventional silica-based systems. By adjusting the silane chemistry and loading levels, the patent maintains high durability while achieving low tanδ, overcoming the limitations of silica substitution.
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 amidine structure improves the chemical interaction between filler and rubber, resulting in a rubber composition with enhanced reinforcing performance, reduced hysteresis loss, and improved scorch resistance, maintaining high elastic modulus and low tanδ without increasing viscosity or compromising workability.
Implementation Method 1
the compound A has an amidine structure represented by the following formula (I) and has a functional group reactive with the diene-based rubber
Implementation Method 2
incorporation of a compound having an amidine structure and having a functional group reactive with a diene-based rubber can solve the above-mentioned problems
Implementation Method 3
incorporation of a compound having an amidine structure and having a functional group reactive with a diene-based rubber can solve the above-mentioned problems
Data Source
AI summary
The invention provides a rubber composition prepared by mixing, per 100 parts by mass of the rubber component comprising at least 50% by mass of a diene-based rubber, from 20 to 150 parts by mass of a filler, and from 0.05 to 30 parts by mass of a compound A which has a specific amidine structure and has a functional group reactive with the diene-based rubber. The rubber composition improves both a high elastic modulus and a low tanδ. The invention also provides a pneumatic tire using the rubber composition.