Fluoropolymer Dispersion Purification via Nonionic Surfactant Stabilization
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Solution Overview
Problem
Existing methods for producing fluoropolymer aqueous dispersions do not effectively reduce the content of fluorine-containing compounds with hydrophilic groups and 7 or fewer carbon atoms.
Innovation Solution
A method involving the polymerization of fluoromonomers in the presence of a fluorine-containing surfactant and an aqueous medium, followed by the addition of a nonionic surfactant, pH regulation to 7 or higher, temperature regulation to 35°C or higher, and treatment with an ion exchange resin or adsorbent to reduce the content of fluorine-containing compounds with hydrophilic groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fluorine-containing emulsifier is used in the aqueous fluoropolymer dispersion, then the dispersion stability is improved, but the content of fluorine-containing compounds with hydrophilic groups and 7 or fewer carbon atoms increases
Solution Approach 1:
The patent applies extraction by removing the harmful fluorine-containing emulsifier from the dispersion system. Through contact with an anion exchanger, the fluorine-containing emulsifier is extracted and removed from the aqueous dispersion, separating it from the fluoropolymer particles while maintaining dispersion stability through the nonionic emulsifier.
Solution Approach 2:
The patent uses a nonionic emulsifier as an intermediary substance that replaces the fluorine-containing emulsifier. This nonionic emulsifier serves as a mediator to maintain dispersion stability without introducing harmful fluorine-containing compounds, thereby resolving the contradiction between stability and contaminant content.
2Quantity of substance
If the aqueous dispersion is treated to remove fluorine-containing emulsifier, then the content of fluorine-containing compounds is reduced, but the dispersion stability may deteriorate
Solution Approach 1:
The nonionic emulsifier acts as an intermediary that ensures dispersion stability is maintained during the removal process. It compensates for the loss of the fluorine-containing emulsifier by providing alternative stabilization, preventing deterioration of dispersion stability while achieving reduction of fluorine-containing compounds.
Solution Approach 2:
The patent changes the chemical parameters of the emulsifier system by switching from a fluorine-containing emulsifier to a nonionic emulsifier. This parameter change allows the system to maintain dispersion stability properties while eliminating the harmful fluorine-containing compounds through subsequent treatment.
3Manufacturing precision
If an anion exchanger is used to remove fluorine-containing emulsifier, then the purification efficiency is improved, but the process complexity increases
Solution Approach 1:
The anion exchanger is used to extract and remove the fluorine-containing emulsifier from the dispersion. This extraction process achieves high purification efficiency by selectively removing the harmful compounds while leaving the fluoropolymer and nonionic emulsifier intact, despite the added process complexity.
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 method achieves a significant reduction in the content of fluorine-containing compounds with hydrophilic groups and 7 or fewer carbon atoms in the fluoropolymer aqueous dispersion, improving the dispersion's properties.
Implementation Method 1
bringing the aqueous dispersion containing the nonionic surfactant into contact with at least one treatment agent selected from the group consisting of an ion exchange resin and an adsorbent
Implementation Method 2
bringing the aqueous dispersion containing the nonionic surfactant into contact with at least one treatment agent selected from the group consisting of an ion exchange resin and an adsorbent
Implementation Method 3
adding a nonionic surfactant to the resulting aqueous dispersion
Data Source
AI summary
Provided is a method for producing a fluoropolymer aqueous dispersion containing a fluoropolymer, the method comprising: polymerizing a fluoromonomer in the presence of a fluorine-containing surfactant and an aqueous medium to prepare an aqueous dispersion containing a fluoropolymer, adding a nonionic surfactant to the resulting aqueous dispersion and also regulating a pH of the aqueous dispersion to 7 or higher and regulating a temperature of the aqueous dispersion to 35°C or higher, and bringing the aqueous dispersion containing the nonionic surfactant into contact with a treatment agent.