Silica Compounding Additive for Rubber Stiffness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The dispersion of hydrophilic silica in hydrophobic rubber formulations is challenging due to its tendency to associate with the aqueous phase, leading to non-uniform blending and increased manufacturing costs, and existing solutions often result in reduced dynamic stiffness and increased hysteresis in silica-filled tire tread compounds.
Innovation Solution
Incorporating a silica compounding additive with a specific structural formula, which includes a divalent metal and organic groups, into the rubber formulation to enhance low strain dynamic stiffness without significantly increasing hysteresis, allowing for improved tire handling performance and retention of low rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hydrophilic silica is dispersed in hydrophobic rubber formulations, then reinforcement benefits are achieved, but non-uniform blending occurs due to silica's tendency to associate with the aqueous phase
Solution Approach 1:
The patent employs silane coupling agents as intermediary substances that bridge the hydrophilic silica particles and the hydrophobic rubber matrix. The silane molecules have both hydrophilic groups that bond to silica surface and hydrophobic organic groups that are compatible with rubber, thereby achieving uniform dispersion while maintaining reinforcement benefits
Solution Approach 2:
The patent modifies the surface properties of silica particles through chemical treatment with silane compounds, changing the surface polarity from hydrophilic to hydrophobic. This parameter change in surface chemistry enables compatible interaction between silica and hydrophobic rubber, resolving the blending uniformity issue
2Stability of the object's composition
If conventional processing aids are used to facilitate mixing and dispersion of filler particles, then dispersion is improved, but manufacturing cost increases and product performance may be negatively affected
Solution Approach 1:
The patent enables the silica particles themselves to provide the dispersing function through surface-modified silane groups that create steric and electrostatic repulsion between particles. This self-dispersing capability eliminates or reduces the need for additional conventional processing aids, thereby lowering manufacturing costs while maintaining good dispersion
3Loss of energy
If silica is used as filler, then rolling resistance is lowered and wet traction is improved, but low strain dynamic stiffness is reduced
Solution Approach 1:
The patent creates a composite structure at the silica-rubber interface through silane coupling, forming a hybrid material system that combines the low hysteresis characteristics of silica with enhanced mechanical properties. The interfacial composite structure provides both low rolling resistance and improved low strain dynamic stiffness simultaneously
4Productivity
If high-shear milling is used for dry blending of silica and rubber, then mixing is enhanced, but filler particles agglomerate and polymer degradation occurs
Solution Approach 1:
The patent performs preliminary surface modification of silica particles with silane coupling agents before the mixing process. This pre-treatment creates a protective hydrophobic coating on silica surfaces that prevents agglomeration during high-shear mixing, enabling efficient mixing without the harmful agglomeration effect
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 additive increases low strain dynamic stiffness, improving tire handling performance while maintaining low hysteresis and rolling resistance, enabling the use of process aids without further reducing stiffness, thus enhancing the processing and performance of silica-filled rubber compounds.
Implementation Method 1
a silica compounding additive of the structural formula: wherein M represents a divalent metal
Implementation Method 2
Incorporating a silica compounding additive with a specific structural formula, which includes a divalent metal and organic groups, into the rubber formulation to enhance low strain dynamic stiffness without significantly increasing hysteresis
Data Source
AI summary
This invention is based upon the discovery that the silica compounding additives of this invention can be included in silica reinforced rubber formulations to increase the low strain dynamic stiffness exhibited by the rubber composition without a substantial increase in the cured compound hysteresis. This increase in stiffness allows for use of process aids that would otherwise result in an unacceptable further reduction in low strain dynamic stiffness. The present invention specifically discloses a rubber formulation which is comprised of (1) a rubbery polymer, (2) a reinforcing silica, and (3) a silica compounding additive of the structural formula:wherein M represents a divalent metal, and wherein R1 and R2 can be the same or different and are selected from the group consisting of hydrogen atoms, alkyl groups, alkylene groups, hydroxyl substituted alkyl or alkylene groups, amine substituted alkyl or alkylene groups and thiol substituted alkyl or alkylene groups.