Halo-Functional Silane for Rubber Coupling
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Solution Overview
Problem
The use of silica as a filler in truck tire treads is limited due to poor abrasion resistance and ineffective coupling with natural rubber, while existing non-sulfur silanes suffer from inadequate coupling performance, VOC emissions, and scorch issues, hindering the replacement of carbon black in rubber compositions.
Innovation Solution
A halo-functional silane containing an alkanedioxysilyl group is developed, which provides improved coupling interactions between silica and rubber, reducing VOC emissions and enhancing abrasion resistance, and is used in a rubber composition that includes a silane-reactive filler and an activating agent to improve filler dispersion and scorch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If silica is used to replace carbon black filler in natural rubber formulations, then rolling resistance is reduced and wet traction is improved, but abrasion resistance deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the silane coupling agent by introducing a cyclic orthoester group structure. This structural modification enables the silane to form stronger covalent bonds with natural rubber polymer chains while maintaining effective coupling with silica surface, thereby improving abrasion resistance without sacrificing the low rolling resistance benefit of silica filler
Solution Approach 2:
The patent creates a composite coupling system where the orthoester-functional silane acts as an interfacial material bridging silica filler and natural rubber matrix. This composite approach at the molecular level ensures strong filler-polymer adhesion, enabling the rubber composite to simultaneously achieve low rolling resistance from silica and high abrasion resistance from effective coupling
2Reliability
If non-sulfur silanes are used to improve coupling between fillers and polymer, then coupling performance is enhanced, but scorch time decreases and filler dispersion deteriorates
Solution Approach 1:
The patent designs the silane molecule with a cyclic orthoester group that remains stable during mixing and processing but activates under curing conditions. This preliminary structuring allows the silane to stay dormant during compounding (maintaining good filler dispersion and acceptable scorch time) and then form strong coupling bonds during vulcanization (achieving excellent coupling performance)
Solution Approach 2:
The patent modifies the reactivity parameter of the silane coupling agent by incorporating the cyclic orthoester group, which changes the activation energy and reaction kinetics. This parameter change allows controlled coupling performance - the silane remains relatively inert during mixing but becomes highly reactive under curing conditions, thus achieving good filler dispersion, acceptable scorch time, and excellent coupling performance
3Reliability
If halo-functional silane derived from mono-alcohols is used to improve coupling, then coupling efficiency is enhanced, but VOC emissions increase and environmental impact worsens
Solution Approach 1:
The patent changes the chemical structure of the silane coupling agent by replacing linear alkoxysilyl groups with cyclic orthoester-functional silyl groups. This structural parameter change maintains the coupling efficiency by preserving the reactive silane functionality while eliminating the formation of volatile mono-alcohol byproducts, thus reducing VOC emissions and environmental impact
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 halo-functional silane enhances the coupling efficiency of silica with rubber, reducing VOC emissions and improving abrasion resistance, allowing for the use of higher silica levels and lower carbon black content in tire treads while maintaining low scorch times and good filler dispersion.
Implementation Method 1
The halo-functional silane enhances the coupling efficiency of silica with rubber
Implementation Method 2
improve filler dispersion
Implementation Method 3
reacting a halo-functional silane derived from mono-alcohol with at least one polyhydroxyl-containing compound and removing by-product mono-alcohol
Implementation Method 4
at least one activating agent
Data Source
AI summary
A halo-functional silane possesses halogen functionality and alkanedioxysilyl functionality.