Propylene-Based Insulating Layer for High-Frequency Cable
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Solution Overview
Problem
High-frequency cables face limitations in achieving superior dielectric characteristics, crush resistance, and heat resistance due to the use of polyethylene-based insulating layers, which become brittle and lack mechanical strength when foamed, and propylene-based resins may not adequately reduce dielectric tangent in the gigahertz band.
Innovation Solution
A propylene-based copolymer with a melting point of 125-145°C, containing ≤7% ethylene and butene, and a crystallization peak temperature difference of 30-40°C from the melting point, is used in the insulating layer, along with a metallocene catalyst for synthesis to enhance molecular weight distribution and flexibility, and a thin non-foamed layer to prevent embrittlement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyethylene is used for the insulating layer to achieve superior dielectric characteristics, then dielectric characteristics are improved, but mechanical strength decreases and the layer becomes easily crushed
Solution Approach 1:
The patent changes the material parameters by using propylene-based resin instead of polyethylene, and specifically controls the melting point (100-140°C) and compositional parameters (ethylene and butene content) to achieve a balance between dielectric characteristics and mechanical strength
Solution Approach 2:
The patent uses composite material strategy by incorporating specific additives (antioxidants, metal deactivators) into the propylene-based resin system to enhance both mechanical properties and dielectric characteristics simultaneously
2Temperature
If propylene-based resin is used to improve heat resistance, then heat resistance is improved, but dielectric tangent increases in the gigahertz band
Solution Approach 1:
The patent precisely controls the melting point parameter (100-140°C) and compositional parameters (ethylene content 1-10%, butene content 1-10%) of the propylene-based resin to optimize the balance between heat resistance and dielectric tangent in the gigahertz band
Solution Approach 2:
The patent applies different compositional qualities within the propylene-based resin system by carefully controlling the types and amounts of comonomers (ethylene, butene) to achieve local optimization of crystallinity and molecular structure for simultaneous heat resistance and low dielectric tangent
3Length of moving object
If the insulating layer thickness is reduced to accommodate smaller cable diameter, then cable diameter is reduced, but mechanical strength decreases and crush resistance is compromised
Solution Approach 1:
The patent changes the material parameters of the insulating layer by using propylene-based resin with specific melting point and compositional characteristics, enabling thinner layers (while maintaining adequate crush resistance through material property optimization rather than relying solely on thickness)
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 solution provides superior dielectric characteristics, crush resistance, and heat resistance while maintaining flexibility and preventing low-temperature embrittlement in high-frequency cables.
Implementation Method 1
a propylene-based copolymer which has a melting point of 125-145°C
Implementation Method 2
the difference between the melting point determined from the portion of the peak of the heat of melting and the crystallization peak temperature determined from the portion of the peak of the heat of crystallization
Data Source
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AI summary
The present invention is an insulated wire provided with a conductor and an insulating layer that covers the conductor, wherein the insulating layer contains a propylene-based copolymer obtained by synthesis using a metallocene catalyst, and an antioxidant having a chemical structure that differs from a hindered phenol structure, and the antioxidant is incorporated at a ratio of not less than 0.01 parts by mass to less than 1.5 parts by mass based on 100 parts by mass of the propylene-based copolymer.