PFA Copolymer Composition for Thin-Wall Molding and Chemical Resistance
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Solution Overview
Problem
Current tetrafluoroethylene copolymers fail to provide formed articles with excellent high-temperature mechanical properties, crack resistance, and chemical resistance while maintaining moldability and low permeability, especially when exposed to chemicals and high temperatures.
Innovation Solution
A copolymer comprising tetrafluoroethylene and perfluoro(propyl vinyl ether units with a specific content range, optimized melt flow rate, and controlled functional groups, which enhances moldability, chemical resistance, and low permeability, and allows for the formation of thin, high-quality coatings on small-diameter core wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the content of perfluoro(propyl vinyl ether) unit is increased to improve moldability and injection rate, then the injection molding speed and thin-walled part formation improve, but the high-temperature rigidity and mechanical strength deteriorate
Solution Approach 1:
The patent precisely controls the content of perfluoro(propyl vinyl ether) unit within 4.2-4.9% by mass and melt flow rate within 19.0-27.0 g/10 min to achieve the optimal balance between injection molding speed and high-temperature rigidity. This parameter optimization allows the copolymer to be molded at high speeds while maintaining sufficient mechanical strength at elevated temperatures.
2Ease of manufacture
If the melt flow rate is increased to improve moldability and filling of thin-walled parts, then the injection rate and formation of complex shapes improve, but the mechanical strength and chemical resistance deteriorate
Solution Approach 1:
The patent optimizes the melt flow rate to a specific range of 19.0-27.0 g/10 min, which is higher than conventional PFA resins but controlled to prevent excessive degradation of chemical resistance. This controlled parameter change enables excellent moldability for thin-walled and complex parts while maintaining adequate chemical resistance for practical applications.
3Object-affected harmful factors
If the number of functional groups is reduced to improve chemical resistance and prevent corrosion, then the corrosion resistance to metal molds and core wires improves, but the moldability and injection rate deteriorate
Solution Approach 1:
The patent maintains the number of functional groups at 50 or less per 10^6 main-chain carbon atoms, which provides sufficient corrosion resistance to metal molds and core wires. Simultaneously, the melt flow rate is increased to 19.0-27.0 g/10 min to compensate for the limited functional groups, thereby maintaining high injection rates and productivity.
4Reliability
If the copolymer composition is optimized for high-temperature mechanical properties and crack resistance, then the resistance to chemicals and high-temperature environments improves, but the moldability and ability to form thin-walled parts deteriorate
Solution Approach 1:
The patent achieves a delicate balance by controlling the perfluoro(propyl vinyl ether) unit content at 4.2-4.9% by mass and melt flow rate at 19.0-27.0 g/10 min. This composition optimization provides sufficient crack resistance and chemical resistance for high-temperature applications while maintaining excellent moldability for forming thin-walled parts with wall thicknesses of 0.1-1.0 mm.
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 4.2 to 4.9% by mass with respect to the whole of the monomer units, a melt flow rate at 372° C. of 19.0 to 27.0 g/10 min, and the number of functional groups of 50 or less per 106 main-chain carbon atoms.