High Purity Perfluoroelastomer Parts via Non-Metallic Coagulation
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Solution Overview
Problem
Current processes for producing perfluoroelastomers result in high metallic ion contamination and perfluoro carboxylic acid concentrations, which are undesirable in applications like semiconductor manufacturing and pharmaceutical industries that require low metal ion and acid concentrations for purity and safety.
Innovation Solution
The method involves using non-metallic buffers and corrosion-resistant materials in polymerization, eliminating metallic coagulants, and curing perfluoroelastomeric gum at high temperatures without additional chemicals, resulting in crosslinked perfluoroelastomer parts with significantly reduced metallic ion and perfluoro carboxylic acid concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If metallic salts are used for coagulation of emulsion or dispersion, then coagulation is achieved, but metallic contamination is added to the elastomeric crumb and perfluoro carboxylic acid removal becomes difficult
Solution Approach 1:
The patent removes metallic salts from the coagulation process entirely, replacing them with non-metallic alternatives such as calcium carbonate or magnesium carbonate. This extraction of the harmful metallic component eliminates the source of metallic ion contamination while preserving the coagulation function through alternative chemical mechanisms.
Solution Approach 2:
The patent introduces non-metallic buffering agents and coagulants as intermediary substances that mediate the coagulation process without introducing metallic contamination. These intermediaries facilitate the separation and coagulation of elastomeric crumb while maintaining purity, acting as a bridge between the emulsion and final product without the harmful effects of metallic salts.
2Ease of manufacture
If perfluoro carboxylic acid salts are used in polymerization, then polymerization is facilitated, but metal ion contamination occurs and perfluoro carboxylic acid concentration increases
Solution Approach 1:
The patent changes the chemical parameters of the polymerization system by substituting metallic perfluoro carboxylic acid salts with non-metallic alternatives. This parameter change maintains the necessary catalytic and buffering functions while fundamentally altering the composition to eliminate metal ion contamination and reduce perfluoro carboxylic acid concentrations to below detectable levels.
Solution Approach 2:
The patent extracts and removes metallic components from the polymerization system, eliminating the source of contamination while preserving the essential polymerization functionality through non-metallic catalysts and buffering agents.
3Strength
If crosslinking catalysts or additives are added during compounding, then sufficient crosslinking is achieved, but metallic and other contaminants are added to the perfluoroelastomer
Solution Approach 1:
The patent enables the perfluoroelastomer to achieve crosslinking through its own inherent chemical structure and thermal properties, without requiring external crosslinking catalysts or additives. The polymer undergoes self-crosslinking during high-temperature processing, eliminating the need for contaminating substances while achieving the necessary crosslinked network structure for mechanical strength and compression set resistance.
4Strength
If fillers such as carbon black or metallic fillers are added for reinforcement, then mechanical strength is improved, but transparency is lost and additional contamination sources are introduced
Solution Approach 1:
The patent changes the reinforcement strategy by eliminating traditional opaque fillers and instead achieving mechanical strength through controlled crosslinking density and polymer network structure. This parameter change in the reinforcement mechanism maintains transparency while providing the necessary mechanical properties through the crosslinked elastomeric network itself.
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 approach produces perfluoroelastomer parts with metallic ion contamination more than 100 times lower than previous methods, achieving transparency and high purity with compression set values below 35% at 200°C, making them suitable for high-purity applications.
Implementation Method 1
curing perfluoroelastomeric gum at high temperatures without additional chemicals, resulting in crosslinked perfluoroelastomer parts
Implementation Method 2
a small percentage of cure site monomer is copolymerized with the perfluorinated monomer units
Data Source
AI summary
Crosslinkable perfluoroelastomer compositions having low metal content and low compression set when crosslinked, and processes for producing the same, are provided. Compositions comprising terpolymers of TFE, PAVE, and CNVE having a metal content of less than 3000 ppb may be formed into high purity transparent perfluoroelastomer parts.