Modified PTFE Powder Core-Shell Structure for High-Frequency Moldability
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Solution Overview
Problem
Existing fluoropolymers face challenges in achieving both good moldability and electrical characteristics, particularly in high-frequency bands, with known materials either being difficult to process or having inferior electrical properties.
Innovation Solution
A modified polytetrafluoroethylene powder is developed with a dielectric loss tangent of not higher than 2.0×10−4 at 12 GHz and a cylinder extrusion pressure of not higher than 45 MPa at a reduction ratio of 1600, achieved through a polymerization process involving specific fluoroolefins, fluoro(alkyl vinyl ethers, and vinylic heterocyclic compounds, along with a chain transfer agent, resulting in a polymer with a core-shell structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tetrafluoroethylene homopolymers are used, then electrical characteristics are excellent, but molding/processing becomes difficult
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the particle core consists of TFE homopolymer (providing excellent electrical characteristics) and the particle shell consists of modified PTFE with copolymer units (providing good moldability). This allows different regions of the same particle to have different properties, simultaneously achieving both excellent electrical characteristics and good molding processability.
2Ease of manufacture
If melt-processable polymers are used, then moldability is improved, but electrical characteristics deteriorate
Solution Approach 1:
The patent creates a core-shell structure where the particle core consists of TFE homopolymer (providing excellent electrical characteristics) and the particle shell consists of modified PTFE with copolymer units (providing good moldability). This allows different regions of the same particle to have different properties, simultaneously achieving both excellent electrical characteristics and good molding processability.
3Ease of manufacture
If modified PTFE fine powder with low extrusion pressure is used, then moldability is improved, but electrical characteristics become inferior
Solution Approach 1:
The patent creates a core-shell structure where the particle core consists of TFE homopolymer (providing excellent electrical characteristics) and the particle shell consists of modified PTFE with copolymer units (providing good moldability). This allows different regions of the same particle to have different properties, simultaneously achieving both excellent electrical characteristics and good molding processability.
4Reliability
If TFE-based resin with core-shell structure is used, then electrical characteristics are improved, but moldability/processability cannot be optimized
Solution Approach 1:
The patent applies parameter changes by carefully controlling the content of copolymer units (fluoroolefin units, fluoro(alkyl vinyl ether) units, and vinylic heterocyclic compound units) to be within specific ranges (0.01-5 mol% each). This precise control of compositional parameters, combined with the core-shell structure, allows the resin to achieve both excellent electrical characteristics and good moldability simultaneously.
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
The modified polytetrafluoroethylene powder exhibits excellent moldability and electrical characteristics, enabling its use in high-frequency applications such as coaxial cables and microwave bands while maintaining low dielectric loss tangent and extrusion pressure.
Implementation Method 1
a method of producing a tetrafluoroethylene polymer which contains step (1) charging a reaction system in the initial stage of polymerization reaction with a fluoroolefin... initiating the polymerization reaction and carrying out the polymerization reaction
Data Source
AI summary
The present invention provides a polytetrafluoroethylene powder having moldability/processability as well as electrical characteristics in microwave bands. The present invention is a modified polytetrafluoroethylene powder which has (1) a dielectric loss tangent at 12 GHz of not higher than 2.0×10−4 and (2) a cylinder extrusion pressure of not higher than 45 MPa at a reduction ratio of 1600.