Fluoropolymer Coatings for Elastomeric Substrates
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Solution Overview
Problem
There is a challenge in achieving acceptable dissolution of highly fluorinated polymers, particularly perfluoroelastomers, in solvents, which complicates the preparation of coating compositions with high fluoropolymer content while maintaining suitable viscosity for thin coating layers on substrates, and there is a need for cost-effective methods to impart enhanced properties to elastomeric materials.
Innovation Solution
A method involving a composition of a copolymer comprising at least 90% by weight of units derived from tetrafluoroethene (TFE) and perfluorinated alkyl ethers, combined with a partially fluorinated solvent, applied to a substrate, with optional curing to form a thin fluoropolymer layer that enhances properties such as reduced permeation, solvent swell resistance, and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If highly fluorinated polymers (perfluoroelastomers) are used to achieve enhanced chemical and thermal resistance, then the substrate gains outstanding stability and inertness, but the dissolution in solvents becomes difficult and coating preparation becomes inconvenient
Solution Approach 1:
The patent changes the chemical composition parameters of the fluoropolymer by using copolymers with specific monomer ratios (at least 50 mol% TFE units and at least 10 mol% perfluorinated ether units) to achieve optimal balance between dissolution properties and chemical resistance. This parameter optimization allows the polymer to dissolve adequately in solvents while maintaining the desired performance characteristics.
Solution Approach 2:
The invention uses composite fluoropolymer systems consisting of copolymers containing both TFE units and perfluorinated ether units. This composite structure combines the chemical resistance of TFE with the enhanced dissolution properties of perfluorinated ether segments, creating a material that satisfies both contradictory requirements.
2Stability of the object's composition
If perfluorinated solvents are used to dissolve perfluoroelastomers, then dissolution is achieved, but the coating viscosity becomes unsuitable for forming thin coating layers
Solution Approach 1:
The patent optimizes the solvent system by selecting specific perfluorinated solvents and controlling their proportion in the coating composition. By adjusting solvent parameters (type and amount), the formulation achieves adequate polymer dissolution while maintaining viscosity within the range suitable for applying thin coating layers (0.1-10 micrometers).
Solution Approach 2:
The invention creates local optimization in the coating composition by using a specific ratio of polymer to solvent and selecting solvents with appropriate boiling points and solvating power. This localized control of composition ensures that dissolution is sufficient for coating formation while viscosity remains manageable for thin layer application.
3Reliability
If high content of fluoropolymer is used in coating compositions, then enhanced properties are achieved, but the coating viscosity increases and becomes unsuitable for thin coating applications
Solution Approach 1:
The patent carefully controls the fluoropolymer content parameter in the coating composition, maintaining it within an optimized range that provides sufficient enhanced properties while keeping viscosity manageable. The specific copolymer composition (with defined TFE and perfluorinated ether unit ratios) allows for this optimization by providing adequate performance at lower concentrations.
Solution Approach 2:
The perfluorinated ether units in the copolymer act as an intermediary that improves dissolution and reduces viscosity. These units serve as a bridge between the highly resistant TFE segments and the solvent, facilitating better solubility and lower viscosity while maintaining the overall performance of the coating.
4Reliability
If conventional fluoropolymer coatings are applied to elastomeric substrates, then chemical resistance is improved, but the cost increases significantly due to the expensive nature of fluoropolymers
Solution Approach 1:
The patent optimizes the fluoropolymer content and composition parameters to achieve the minimum necessary amount for providing adequate chemical resistance. By using copolymers with specific monomer ratios and controlling the coating thickness (0.1-10 micrometers), the invention reduces the total quantity of expensive fluoropolymer material required while maintaining the necessary performance level.
Solution Approach 2:
The invention applies fluoropolymer coating only where necessary on the elastomeric substrate, creating a localized protective layer with optimal thickness. This localized application provides chemical resistance at the interface where it is most needed while minimizing the total amount of expensive fluoropolymer material used.
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 allows for the creation of fluoropolymer coating compositions with high fluoropolymer content, maintaining excellent viscosity characteristics and providing cost-effective enhancement of elastomeric substrates with improved resistance to permeation, solvent swell, and chemical exposure.
Implementation Method 1
achieving acceptable dissolution of highly fluorinated polymers, in particular perfluoroelastomers, in solvents
Implementation Method 2
at least partially removing the at least one solvent
Data Source
AI summary
The present disclosure relates to a method of treating a substrate comprising an elastomeric material, wherein the method comprises the steps of: a) providing a composition comprising: i. at least one fluoropolymer which is a copolymer comprising at least 90% by weight, based on the total weight of the copolymer, of units derived from tetrafluoroethene (TFE) and from one or more perfluorinated alkyl ethers corresponding to the general formula (I): Rf1—O—(CF2)n—CF═CF2 (I) wherein n is 1 or 0 and Rf1 represents a perfluoroalkyl residue which is optionally interrupted once or more than once by an oxygen atom; and ii. at least one solvent comprising a linear, cyclic or branched, partially fluorinated (poly)ether; b) contacting at least part of the substrate with the composition of step a); c) at least partially removing the at least one solvent; and d) optionally, when the fluoropolymer is curable, subjecting the fluoropolymer to curing, wherein the curing step may be carried out simultaneously with or after step c).