Stable Aqueous Silane Composition via Controlled Hydrolysis and Methanol Removal
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Solution Overview
Problem
Existing aqueous compositions of N-benzyl-substituted N-(2-aminoethyl)-3-aminopropylsiloxane hydrochlorides are unstable and have high VOC content, leading to precipitation and inhomogeneity, especially at elevated storage temperatures, limiting their application as adhesion promoters and fillers.
Innovation Solution
A controlled hydrolysis process of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane with benzyl chloride and hydrochloric acid, followed by distillation to remove methanol, results in a low-VOC, storage-stable, and clear aqueous composition with up to 60% active substance content, which is substantially methanol-free and stable for at least 1 year at room temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous solutions of N-(N-benzyl-2-aminoethyl)-3-aminopropyltrimethoxysilane hydrochloride are prepared, then the composition can be used as an adhesion promoter, but the solution becomes unstable and forms inhomogeneous cloudy precipitates
Solution Approach 1:
The patent applies parameter changes by controlling the hydrolysis process parameters (water to silicon ratio of 1.15-1.25 mol/mol, temperature of 40-60°C, pH 2-4) to achieve complete hydrolysis of methoxy groups while maintaining solution stability. This transforms the unstable alkoxy-silane into stable hydroxyl-silane compounds that remain homogeneous in aqueous solution.
Solution Approach 2:
The patent utilizes phase transition control by managing the hydrolysis reaction to convert methoxy groups to hydroxyl groups, changing the chemical phase state of the silane compound. This phase transition from alkoxy to hydroxyl form eliminates the precipitation issue and ensures long-term storage stability.
2Quantity of substance
If conventional hydrolysis processes are used to produce water-soluble hydrolysates, then the composition becomes water-soluble, but the active substance content is reduced and VOC content increases
Solution Approach 1:
The patent applies extraction by removing methanol through controlled distillation after hydrolysis, separating the harmful VOC component from the active substance. This allows concentration of the active silane compound while eliminating methanol, achieving both high active substance content (40-60% wt.) and low VOC content (≤0.5% wt.).
Solution Approach 2:
The patent discards methanol as a harmful byproduct while recovering and concentrating the valuable active substance. The distillation process selectively removes methanol vapor, leaving behind the high-concentration hydrolyzed silane product, thus converting waste removal into substance concentration.
3Temperature
If the composition is stored at elevated temperatures, then the composition remains stable, but precipitation and inhomogeneity occur
Solution Approach 1:
The patent applies beforehand cushioning by performing complete hydrolysis and methanol removal during production, creating a pre-stabilized composition that is resistant to temperature-induced precipitation. The thorough hydrolysis converts all methoxy groups to stable hydroxyl groups, providing a buffer against thermal degradation and maintaining homogeneity even at elevated storage temperatures.
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 resulting composition is colorless, stable, and miscible with water, maintaining its properties even at elevated temperatures, making it suitable for various applications as an adhesion promoter and filler modifier with enhanced storage stability and reduced VOC content.
Implementation Method 1
A controlled hydrolysis process of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane with benzyl chloride and hydrochloric acid
Implementation Method 2
followed by distillation to remove methanol
Data Source
AI summary
An aqueous composition contains N-benzyl-substituted N-(2-aminoethyl)-3-aminopropylsiloxane hydrochlorides, wherein the composition after storage for 6 weeks at 60° C. has a color number of ≤1 Gardner, a content of methanol of ≤0.5% by weight, an active substance content of ≤60% by weight, and a content of water of ≥40% to ≤60% by weight, and wherein the components in the composition sum to 100% by weight.