Silicone Resin Concentration via Liquid-Liquid Extraction
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Solution Overview
Problem
Current methods for increasing the solids concentration of silicone resin solutions, such as adjusting reactant stoichiometry or using heat and vacuum, often compromise other performance attributes like hardness and adhesion, and are time-consuming or risk excessive silanol group condensation.
Innovation Solution
A method involving the extraction of a silicone resin solution with an aqueous extractant to separate into distinct layers, where the lower layer contains a higher concentration of resin solids without the need for heat or vacuum, allowing for a stable and efficient increase in solids content from 5 to 70 weight percent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If heat and vacuum are applied to strip solvents and concentrate resin, then solids concentration increases, but excessive silanol group condensation occurs which negatively impacts adhesion and hardness
Solution Approach 1:
The patent applies liquid-liquid extraction using an aqueous extractant to selectively remove solvents from the silicone resin solution. The mixture separates into two phases: an upper aqueous phase containing removed solvents and a lower organic phase containing concentrated resin solids. This extraction method increases solids concentration to 40-70% without applying heat or vacuum, thereby preventing excessive silanol condensation and preserving adhesion and hardness properties.
2Quantity of substance
If aggressive heat and vacuum are applied for extended periods to increase solids, then concentration increases, but significant silanol functional group condensation occurs
Solution Approach 1:
The patent replaces the thermal-mechanical stripping process (heat and vacuum) with a chemical extraction process using aqueous extractants. This substitution allows solvent removal and resin concentration to occur at ambient or mild temperatures, preventing the thermal degradation and excessive condensation of silanol functional groups that occurs during aggressive stripping.
3Quantity of substance
If reactant stoichiometry is adjusted to minimize byproduct formation, then solids concentration increases, but hardness and resistance to cracking are compromised
Solution Approach 1:
The patent creates a concentrated resin solution through extraction that copies the composition and properties of the original resin system, maintaining the same reactant stoichiometry and byproduct profile. This allows the resin to be concentrated to higher solids levels (40-70%) without altering the fundamental chemistry that determines cured coating hardness and crack resistance.
4Quantity of substance
If traditional stripping methods are used to manufacture high resin content grades, then solids level increases to >35%, but the process requires significant time (>24 hours) and careful control to avoid condensation
Solution Approach 1:
The patent exploits liquid-liquid phase separation to achieve rapid resin concentration. When the aqueous extractant is added to the silicone resin solution, the system spontaneously separates into two immiscible liquid phases based on density and solubility differences. This phase transition occurs quickly at ambient temperature, concentrating the resin to 40-70% solids in a fraction of the time required for thermal stripping methods.
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
This method effectively increases the solids concentration of silicone resin solutions to 40-70 weight percent in minimal time, maintaining stability and avoiding the negative impacts of heat or vacuum treatment, such as excessive silanol group condensation, while preserving the performance attributes of the cured coating.
Implementation Method 1
The solution of silicone resin and aqueous extractant are mixed vigorously and allowed to settle. Upon settling the solution provides an upper aqueous layer and a lower layer containing silicone resin solids.
Data Source
AI summary
An improved method for concentrating solids in silicone resin coating compositions is provided, said compositions comprising higher solids levels that are often needed in order to increase the thickness of the final coated film when applied to a given substrate.