Silane Disulfide Vegetable Oils for Rubber Dispersion
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Solution Overview
Problem
Silica-filled rubber formulations face challenges in achieving better extrusion quality and higher dynamic stiffness without compromising other desirable attributes like low hysteresis, particularly due to issues with dispersion and processing difficulties associated with organosilane coupling agents, which lead to reduced mechanical efficiency and increased costs.
Innovation Solution
A vegetable oil derivative with a specific structure, produced through modification of triglycerides via thiol-ene reactions and disulfide exchange, is used in rubber compositions to enhance silica dispersion and dynamic stiffness, potentially replacing or complementing traditional silane coupling agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mercaptosilane coupling agents are used to improve silica dispersion and coupling, then wet and ice skid resistance and rolling resistance are improved, but premature crosslinking occurs at higher temperatures and mechanical mixing efficiency is reduced
Solution Approach 1:
The silane coupling agent is pre-hydrolyzed and allowed to condense on the silica surface before being incorporated into the rubber compound. This preliminary silanization step ensures the silane is already bonded to silica and less reactive when mixed with rubber, preventing premature crosslinking during conventional Banbury mixing while still providing the coupling benefits for improved wet and ice skid resistance
Solution Approach 2:
The silane coupling process is divided into separate stages: first hydrolysis of the silane in aqueous solution, then condensation on silica surface, followed by drying to form a pre-silanized silica product. This segmentation of the silane reaction process allows control over the timing and extent of crosslinking, preventing unwanted premature reactions during rubber compounding
2Object-generated harmful factors
If low mixing temperatures are used to avoid premature crosslinking, then crosslinking is controlled, but mechanical efficiency of mixing is markedely reduced and productivity decreases
Solution Approach 1:
The silane coupling reaction is performed in advance during silica preparation, creating a pre-silanized silica product with controlled crosslinking. This allows conventional high-temperature Banbury mixing to be used for rubber compounding without fear of premature crosslinking, thereby maintaining high mechanical mixing efficiency and productivity
Solution Approach 2:
The pre-silanized silica acts as an intermediary that has already undergone the crosslinking reaction in a controlled manner. This intermediary material can then be incorporated into rubber at high mixing temperatures without causing premature crosslinking of the rubber compound itself, enabling high-productivity processing
3Reliability
If silica is used as a reinforcing filler to lower rolling resistance and improve wet traction, then performance characteristics are improved, but dispersion difficulty in hydrophobic elastomer increases
Solution Approach 1:
The surface properties of silica are chemically modified by introducing organosilane coupling agents that change the surface from hydrophilic to hydrophobic. This parameter change in surface chemistry enables compatible interaction with hydrophobic elastomers, dramatically improving dispersion ease while maintaining the reinforcing benefits for wet traction
Solution Approach 2:
A composite structure is created where silica particles are coated with organosilane coupling agents that provide both silica surface attachment and organic group exposure. This composite material combines the reinforcing properties of silica with the compatibility of organic groups, enabling good dispersion in hydrophobic elastomers while maintaining improved wet traction performance
4Reliability
If organosilane coupling agents are used to improve silica dispersion, then coupling between rubber and silica is enhanced, but unpleasant odors and scorching occur during compounding
Solution Approach 1:
The silane coupling agent is pre-reacted with silica in an aqueous environment where hydrolysis and condensation occur under controlled conditions. This preliminary reaction completes the coupling process before rubber compounding, eliminating the need for high-temperature reactions during mixing that cause scorching and unpleasant odors
Solution Approach 2:
Water acts as an intermediary medium for the silane hydrolysis and condensation reactions. This allows the coupling reaction to proceed under mild, odor-free conditions during silica preparation, rather than requiring high-temperature processing during rubber compounding that generates scorching and unpleasant odors
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 vegetable oil derivative improves the processing and dynamic stiffness of silica-filled rubber compounds, maintaining low hysteresis and enhancing wet and ice traction, while reducing porosity and extrusion issues, thus addressing the limitations of current silica and carbon black compounds.
Implementation Method 1
modification of triglycerides via thiol-ene reactions
Implementation Method 2
disulfide exchange
Implementation Method 3
the alkoxy group hydrolyzes in the presence of moisture typically found on the surface of the silica to form the corresponding silanol which reacts with or condenses in the presence of the silica surface
Implementation Method 4
the alkoxy group hydrolyzes in the presence of moisture typically found on the surface of the silica to form the corresponding silanol which reacts with or condenses in the presence of the silica surface
Data Source
AI summary
The present invention is directed to novel silane disulfide vegetable oils, a method of making the oils, their use in rubber compositions, and their use in tires.