Fluoropolymer Dispersion Shear Stability via Polyhydroxy Surfactants
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Solution Overview
Problem
Fluoropolymer dispersions with low or no fluorinated surfactants exhibit shear instability, which is a challenge in coating applications requiring stable dispersions, as they are prone to coagulation under shear forces.
Innovation Solution
Incorporating non-aromatic polyhydroxy surfactants with an acyclic polyhydroxy unit linked to a long-chain unit via specific linking groups into the fluoropolymer dispersions to enhance their shear stability, allowing for the reduction or elimination of fluorinated surfactants while maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fluorinated surfactants are removed or reduced in fluoropolymer dispersions, then environmental safety and health aspects are improved, but shear stability deteriorates
Solution Approach 1:
The patent introduces non-aromatic polyols as intermediary substances that mediate between the fluoropolymer particles and the aqueous phase. These polyols serve as alternative stabilizing agents that replace the function of fluorinated surfactants without causing environmental harm, thereby maintaining shear stability while eliminating harmful fluorinated compounds
Solution Approach 2:
The patent changes the chemical composition parameters by substituting fluorinated surfactants with non-aromatic polyols having specific molecular weight ranges (500-5000 g/mol) and hydroxyl content (1-10 mmol/g). This parameter change transforms the dispersion system from one relying on fluorinated compounds to one stabilized by environmentally benign polyolic structures
2Loss of substance
If fluorinated surfactants are removed or reduced in fluoropolymer dispersions, then production costs are reduced, but shear stability deteriorates
Solution Approach 1:
The patent employs non-aromatic polyols that are economically more favorable than fluorinated surfactants. These polyols can be derived from renewable resources and are generally less expensive than specialized fluorinated compounds, thereby reducing material costs while providing adequate stabilization function
3Stability of the object's composition
If non-aromatic polyols are used as stabilizing surfactants, then shear stability is improved, but the complexity of formulation increases
Solution Approach 1:
The patent specifies particular local qualities for the polyolic stabilizers, namely molecular weight between 500-5000 g/mol and hydroxyl content of 1-10 mmol/g. By defining these specific local quality parameters, the formulation complexity is managed through targeted specifications rather than requiring complex multi-component systems
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 use of polyhydroxy surfactants significantly improves the shear stability of fluoropolymer dispersions, preventing coagulation and ensuring stable coating compositions even with low fluorinated surfactant content, thereby addressing the instability issues in fluoropolymer-based coatings.
Implementation Method 1
Incorporating non-aromatic polyhydroxy surfactants with an acyclic polyhydroxy unit linked to a long-chain unit via specific linking groups into the fluoropolymer dispersions to enhance their shear stability
Data Source
AI summary
Provided are aqueous fluoropolymer dispersions containing at least one tetrafluoroethene homopolymer or tetrafluoroethene copolymer and at least one non-aromatic polyhydroxy surfactant. The dispersions contain from 0 to 100 ppm based on the total weight of the dispersion of fluorinated surfactants. Also provided are methods of coating using the dispersions and substrate coated with the dispersions.