Fluoropolymer Copolymer Composition for Thick Transparent Sheet Extrusion
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Solution Overview
Problem
Existing copolymers with tetrafluoroethylene and perfluoro(alkyl vinyl ether units face challenges in producing thick sheets with uniform thickness and high transparency, while maintaining high tensile strength, low permeability, and resistance to deformation and chemical solutions.
Innovation Solution
A copolymer with a specific composition of tetrafluoroethylene and perfluoro(propyl vinyl ether units, with a content of 4.9 to 7.0% by mass and a melt flow rate of 0.5 to 1.5 g/10 min, which minimizes deformation in the molten state and enhances transparency, tensile strength, and resistance to air, chemical, and carbon dioxide permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the copolymer contains perfluoro(alkyl vinyl ether) units to improve processability and transparency, then the melt flow rate increases and transparency improves, but the tensile strength decreases and deformation resistance worsens
Solution Approach 1:
The patent applies parameter changes by precisely controlling the content of perfluoro(propyl vinyl ether) units within 4.5-6.6% by mass and the number of unstable terminal groups to 20 or less per 1×10^6 carbon atoms. This optimization balances the melt flow rate (0.5-1.5 g/10 min at 372°C) for good processability while maintaining high tensile strength (20-30 MPa) and deformation resistance in the formed articles.
2Illumination intensity
If the copolymer composition is adjusted to improve transparency, then the haze value decreases and clarity improves, but the chemical solution resistance and permeability properties worsen
Solution Approach 1:
The patent achieves optimal transparency with haze values of 10% or less (typically 2-8%) by controlling the perfluoro(propyl vinyl ether) unit content at 4.5-6.6% by mass. Simultaneously, it maintains excellent chemical solution resistance by limiting unstable terminal groups to 20 or less per 1×10^6 carbon atoms, preventing fluorine ion dissolution in chemical solutions while preserving low permeability to gases and liquids.
3Length of stationary object
If the copolymer is used to produce thick sheets by extrusion, then the sheet thickness increases, but the thickness uniformity decreases and deformation increases
Solution Approach 1:
The patent enables production of thick sheets (5 mm or more, up to 50 mm or more) with excellent thickness uniformity by optimizing the copolymer parameters: perfluoro(propyl vinyl ether) unit content of 4.5-6.6% by mass provides appropriate melt viscosity, while unstable terminal groups of 20 or less per 1×10^6 carbon atoms prevent excessive flow and deformation during extrusion and molding processes.
4Strength
If the copolymer composition is optimized for high tensile strength, then the mechanical strength increases, but the melt flow rate decreases and processability worsens
Solution Approach 1:
The patent achieves both high tensile strength (20-30 MPa) and good processability by precisely balancing multiple parameters: perfluoro(propyl vinyl ether) units at 4.5-6.6% by mass provide sufficient chain flexibility for melt flow, while unstable terminal groups limited to 20 or less per 1×10^6 carbon atoms maintain chain integrity for high strength. The resulting melt flow rate of 0.5-1.5 g/10 min at 372°C enables easy extrusion and molding while preserving mechanical properties.
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.