TFE–PAVE Aqueous Dispersion for Storage Stability and Water-Resistant Coatings
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Solution Overview
Problem
Existing aqueous coating materials containing fluorinated polymers lack sufficient storage stability and water resistance in coating films.
Innovation Solution
An aqueous dispersion comprising fluorinated polymers with specific unit proportions, particle sizes, and ion and emulsifier concentrations, including a concentration of fluoride and sulfate ions below 50 ppm and hydrocarbon-based emulsifiers below 100 ppm, is developed to enhance storage stability and water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluorinated polymer aqueous dispersion is used, then coating film can be formed, but storage stability is insufficient and water resistance is poor
Solution Approach 1:
The patent applies parameter changes by precisely controlling the average particle size of the fluorinated polymer (1-150 nm), the monomer composition ratio (20-60 mol% perfluoro alkyl vinyl ether units), and the concentrations of fluoride ions (≤50 ppm) and sulfate ions (≤50 ppm). These parameter optimizations simultaneously improve storage stability and water resistance of the coating film.
Solution Approach 2:
The patent uses a composite approach by combining fluorinated polymer with specific emulsifiers in controlled concentrations, creating a composite aqueous dispersion system that achieves both improved storage stability and water resistance through synergistic effects of the components.
2Manufacturing precision
If fluorinated polymer content is increased to improve coating performance, then coating film quality improves, but storage stability deteriorates due to particle deposition
Solution Approach 1:
The patent resolves this contradiction by optimizing the average particle size parameter to 1-150 nm and controlling fluoride ion concentration to ≤50 ppm, which prevents particle deposition while maintaining high coating film quality. This parameter optimization allows the system to achieve both goals simultaneously.
3Reliability
If emulsifier concentration is increased to improve dispersion stability, then storage stability improves, but water resistance of coating film deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the emulsifier concentration within specific ranges and optimizing the balance between different emulsifier types. This controlled approach allows the system to achieve adequate dispersion stability without compromising the water resistance of the coating film.
Data Source
AI summary
To provide an aqueous dispersion which is excellent in storage stability and from which a coating film excellent in water resistance can be formed. The aqueous dispersion of the present invention is an aqueous dispersion containing a fluorinated polymer having TFE units and PAVE units, and an aqueous medium, wherein the proportion of the PAVE units is 20 to 60 mol % to the total amount of the TFE units and the PAVE units, the content of the fluorinated polymer is 0.1 to 40 mass % to the total mass of the aqueous dispersion, the average particle size of the fluorinated polymer is 1 to 150 nm, the concentration of fluoride ions and the concentration of sulfate ions are each 50 mass ppm or less to the total mass of the aqueous medium in the aqueous dispersion, and the concentration of a hydrocarbon-based emulsifier is 100 mass ppm or less to the total mass of the fluorinated polymer.