Fluoropolymer Composition for Stable Extrusion of Transparent Thick Sheets
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Solution Overview
Problem
Existing copolymers struggle to maintain form stability in a molten state, achieve uniform thickness in extruded sheets, provide high transparency, and exhibit sufficient tensile strength, abrasion resistance, and chemical resistance, particularly in chemical solutions like hydrogen peroxide.
Innovation Solution
A copolymer comprising tetrafluoroethylene and perfluoro(propyl vinyl ether units with specific content ratios and melt flow rates, along with controlled functional groups, to enhance stability, transparency, and resistance to deformation, chemical permeability, and ion dissolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the copolymer contains perfluoro(alkyl vinyl ether) unit with 4.5 to 6.6% by mass, then it provides good transparency and chemical resistance, but it deforms easily in a molten state and cannot maintain uniform thickness during extrusion forming
Solution Approach 1:
The patent changes the compositional parameters by specifying perfluoro(propyl vinyl ether) unit content of 4.9 to 7.0% by mass (narrowed from the broader 4.5-6.6% range), melt flow rate at 372°C of 0.5 to 1.5 g/10 min, and functional groups of 20 or less per 10^6. These precise parameter adjustments resolve the contradiction by optimizing both chemical resistance and extrusion stability simultaneously.
Solution Approach 2:
The patent creates a composite polymer structure by copolymerizing tetrafluoroethylene with perfluoro(propyl vinyl ether) in specific ratios. This composite approach combines the chemical resistance benefits of fluorinated units with the structural stability needed for extrusion forming, achieving both transparency and manufacturing precision.
2Ease of manufacture
If the copolymer has higher melt flow rate to enable easy extrusion forming, then it can be processed into thick sheets more easily, but it loses form stability and deforms in the molten state
Solution Approach 1:
The patent optimizes the melt flow rate parameter to a specific range of 0.5 to 1.5 g/10 min at 372°C. This precise parameter control resolves the contradiction by ensuring the material flows sufficiently for extrusion while maintaining enough viscosity to prevent deformation in the molten state.
3Adaptability or versatility
If the copolymer contains more functional groups to improve reactivity and processing, then it can be more easily formed into various shapes, but it increases compression set rate and reduces high-temperature tensile strength
Solution Approach 1:
The patent controls the functional groups content to 20 or less per 10^6, establishing an upper limit that prevents excessive crosslinking. This parameter constraint maintains the copolymer's forming capability while preserving its high-temperature mechanical properties and minimizing compression set.
Data Source
AI summary
There is provided a copolymer containing tetrafluoroethylene unit and perfluoro(propyl vinyl ether) unit, wherein the copolymer has a content of perfluoro(propyl vinyl ether) unit of 4.9 to 7.0% by mass with respect to the whole of the monomer units, a melt flow rate at 372°C of 0.5 to 1.5 g/10 min, and the number of functional groups of 20 or less per 106 main-chain carbon atoms.