Silica Masterbatch Hydrophobation with Methoxy Silanes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current processes for incorporating silica into rubber using dry mixing are time-consuming and energy-intensive, and existing wet processes face challenges in achieving complete incorporation and interaction with non-polar polymers, leading to scorch issues and increased costs due to alcohol usage and disposal.
Innovation Solution
A wet process using methoxy silanes to fully hydrophobate silica, allowing for its complete incorporation into a silica masterbatch with improved scorch safety, where the silanes are soluble in alcohol/water mixtures containing at least 70% water, enabling effective interaction with the rubber cure system and reducing alcohol usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry mixing process is used to incorporate silica into rubber, then silica can be effectively blended into rubber, but the process is time-consuming and energy-intensive
Solution Approach 1:
The silane is applied to the silica surface in advance (pre-coating) before the mixing operation. This preliminary action allows the silane to react with the silica surface, creating a reactive coating that facilitates subsequent mixing with rubber. The silane-modified silica is prepared beforehand, so that during the actual mixing process, the reaction and blending occur more rapidly and efficiently, reducing both time and energy requirements.
2Reliability
If silane is used as hydrophobating agent in dry mixing, then silica can be effectively coupled with rubber, but ethanol from silane reaction must be removed requiring extra equipment
Solution Approach 1:
The harmful byproduct (ethanol) is extracted or removed from the system by using an alternative silane compound that does not produce alcohol during reaction. The patent employs silane compounds that react without generating ethanol, thereby eliminating the need for additional alcohol removal equipment and simplifying the overall process while maintaining effective silica-rubber coupling.
3Manufacturing precision
If existing wet process is used to make silica masterbatch, then incorporation into rubber can be achieved, but complete interaction with non-polar polymers is difficult leading to scorch issues
Solution Approach 1:
The chemical parameters of the silane compound are changed to improve compatibility with non-polar polymers. The patent uses silane compounds with specific molecular structures and functional groups that enhance their ability to interact with non-polar rubber matrices. This parameter change in the chemical composition ensures complete incorporation of silica while maintaining proper scorch safety by preventing premature vulcanization.
4Manufacturing precision
If alcohol-based silane solution is used for hydrophobation, then silica can be treated effectively, but alcohol usage and disposal costs increase
Solution Approach 1:
The patent replaces expensive and problematic alcohol-based silane solutions with water-based alternatives. Water is a cheap, readily available, and environmentally friendly solvent that eliminates disposal costs associated with alcohol. The silane compound is formulated to be effective in water-based solutions, providing the same hydrophobation effectiveness without the environmental and economic burden of alcohol usage and disposal.
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 process results in a silica masterbatch with excellent scorch safety and reduced raw material costs, as silica is fully incorporated and processed without scorch issues, enhancing the efficiency and productivity of rubber compounding.
Implementation Method 1
using the methoxy silanes to hydrophobate silica
Implementation Method 2
the silica reacts with the silane to form a reaction mix compound
Implementation Method 3
compounds in Thurn's group have the ability to react both with the silica (through the trialkoxysilane groups) and react with the rubber (through the Sn groups)
Implementation Method 4
Scorch time is a reflection of the fully compounded rubber's ability to be thermally processed without premature vulcanization or crosslinking
Data Source
AI summary
A process for making silica-filled rubber masterbatch using silica hydrophobated with a trimethoxy silane coupling agent. One embodiment uses a mixture of trimethoxy silanes, one or more of which react with rubber to bond the silica to the rubber, and one or more of which do not react with rubber, but do hydrophobate the silica. Hydrophobated silica is mixed with latex polymer and incorporated into rubber during coagulation of the latex, which is preferably coagulated with calcium chloride. The present invention further provides a process for making the trimethoxy silane coupling agents. Preferred trimethoxy silane coupling agents include bis-(3- trimethoxysilylpropyl)disulfide and bis-(3-trimethoxysilylpropyl)-tetrasulfide. Long scorch time of the inventive silica masterbatch allows rubber products, particularly tires, to be compounded at length.