Organofunctional Silanes with Blocked Mercaptan for Low Viscosity
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Solution Overview
Problem
Existing organosilane derivatives face issues such as high viscosities, gellation, flammability risks, and volatile organic compound (VOC) emissions, which limit their effectiveness in elastomer manufacturing and tire production, particularly due to the formation of bridged or cyclic structures and the use of ether-based compounds.
Innovation Solution
The development of organofunctional silane compositions that include both mercaptan and blocked mercaptan functionalities, achieved through the transesterification of mercaptosilanes and blocked mercaptosilanes with polyhydroxy-containing compounds, which form bridged dialkoxysilane structures, reducing VOC emissions and improving coupling efficiency between inorganic fillers and organic polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glycol derivatives of organosilanes are used, then coupling efficiency is improved, but viscosity increases and gellation occurs
Solution Approach 1:
The patent changes the molecular structure parameters of the silane derivative by using specific glycol spacers with controlled chain lengths and introducing blocked mercaptan groups, which modifies the physical properties to reduce viscosity and prevent gellation while maintaining coupling efficiency
Solution Approach 2:
The invention creates a composite structure combining silane functional groups with glycol-based spacer molecules, forming a hybrid organic-inorganic coupling agent that balances reactivity with processability
2Reliability
If polyether-based monol derivatives of sulfur silanes are used, then coupling efficiency is improved, but flammability risk increases due to peroxide formation
Solution Approach 1:
The patent removes the polyether component from the silane structure, extracting the harmful peroxide-forming ether linkages while retaining the essential coupling functionality through alternative glycol-based spacer design
Solution Approach 2:
The invention converts the potential harm of ether peroxide formation into a benefit by deliberately avoiding ether linkages and using hydrocarbon-based glycol spacers that do not form peroxides, thereby eliminating flammability risks while maintaining coupling performance
3Productivity
If blocked mercaptosilanes with monofunctional alcohol-derived hydrolyzable groups are used, then manufacturing steps are reduced, but VOC emissions increase
Solution Approach 1:
The patent changes the hydrolyzable group from simple monofunctional alcohol derivatives to glycol-derived multifunctional groups, which alters the emission profile by reducing VOC volatility while maintaining the simplified processing advantage
Solution Approach 2:
The glycol-based spacer acts as an intermediary structure that connects the mercaptan functional group with the hydrolyzable alkoxy groups, mediating between the need for simple processing and the requirement to minimize harmful emissions
4Reliability
If high levels of mercaptosilane are used to improve coupling efficiency, then coupling performance is improved, but scorch time decreases
Solution Approach 1:
The patent changes the chemical structure by introducing blocked mercaptan groups that can be progressively released, modifying the reactivity profile to extend scorch time while maintaining ultimate coupling efficiency through controlled deblocking during curing
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
These compositions exhibit longer scorch times and improved performance in cured articles by reducing rolling resistance, heat build-up, and wear, while minimizing VOC emissions and processing viscosity, thus enhancing the manufacturing process and product properties.
Implementation Method 1
achieved through the transesterification of mercaptosilanes and blocked mercaptosilanes with polyhydroxy-containing compounds, which form bridged dialkoxysilane structures
Data Source
AI summary
Organofunctional silanes, inclusive of dimers and oligomers, are provided in which individual silanes possess both free and blocked mercaptan functionality or particular mixtures of the organofunctional silanes possess both free and blocked mercaptan functionality. The organofunctional silanes and silane mixtures are useful, inter alia, as coupling agents for elastomeric compositions, e.g., rubber formulations employed in the manufacture of tires, where they exhibit a desirable balance of low scorch and good performance properties