Power Cable Insulation Resin Composition for Heat-Resistant Flexibility
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Solution Overview
Problem
Existing insulating resin compositions for electric power cables face challenges such as poor flexibility, inadequate electrical insulation properties, and susceptibility to thermal deformation and sag, especially when polypropylene is used without crosslinking.
Innovation Solution
A composition comprising a polypropylene resin and a styrene-based thermoplastic elastomer, with a specific temperature characteristic curve of loss tangent tan δ, which enhances flexibility and electrical insulation properties while suppressing thermal deformation and sag without the need for crosslinking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polypropylene is used as the insulating layer without crosslinking, then heat resistance is improved, but flexibility deteriorates
Solution Approach 1:
The patent uses a composite material system consisting of polypropylene as the base resin and EPR (ethylene propylene rubber) as an elastomeric modifier. This combination allows the insulating layer to maintain the high heat resistance of polypropylene while incorporating the flexibility and softness of EPR, thereby resolving the contradiction between heat resistance and flexibility.
2Temperature
If polypropylene is used as the insulating layer, then heat resistance is improved, but electrical insulation property at high temperature deteriorates
Solution Approach 1:
The patent employs a composite material system where polypropylene provides heat resistance and EPR contributes to maintaining electrical insulation properties at elevated temperatures. The synergistic effect of this composite allows the insulating layer to simultaneously achieve both heat resistance and reliable electrical insulation performance.
3Ease of operation
If EPR or TPO is added to polypropylene as a softening agent, then flexibility is improved, but mixing difficulty increases
Solution Approach 1:
The patent introduces a specific intermediary substance to facilitate the mixing of EPR or TPO with polypropylene. This intermediary acts as a compatibilizer that reduces the interfacial tension and improves the dispersion of the elastomer particles within the polypropylene matrix, thereby easing the manufacturing process while maintaining the desired flexibility.
4Reliability
If additives such as epoxy resin, insulating oil, or paraffins are added to improve electrical insulation property, then electrical insulation property is improved, but processing time increases
Solution Approach 1:
The patent utilizes readily available commercial resin compositions that already contain optimized amounts of electrical insulation additives. By selecting pre-formulated resin grades with built-in additives, the patent eliminates the need for separate addition and processing steps, thereby reducing overall processing time while maintaining adequate electrical insulation properties.
5Ease of operation
If EPR and TPO are added to polypropylene, then flexibility is improved, but thermal deformation and sag increase
Solution Approach 1:
The patent carefully controls the composition parameters, specifically limiting the content of EPR and TPO to 5 mass% or less of the total resin composition. By optimizing this compositional parameter, the patent achieves a balance where sufficient flexibility is obtained while minimizing the tendency for thermal deformation and sag that would occur with higher elastomer contents.
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 proposed composition achieves superior flexibility and electrical insulation properties, effectively preventing thermal deformation and sag, thus improving the performance and durability of electric power cables.
Implementation Method 1
a temperature characteristic curve of loss tangent tan δ obtained by dynamic viscoelasticity measurement at a frequency of 100 rad/s has a high-temperature-side temperature region in which the loss tangent tan δ is 0.1 or more and 0.4 or less
Data Source
AI summary
The insulating resin composition for electric power cable includes a polypropylene resin (A) that is a propylene-based polymer, and a styrene-based thermoplastic elastomer (B). The temperature characteristic curve of loss tangent tan δ obtained by dynamic viscoelasticity measurement at a frequency of 100 rad/s has a high-temperature-side temperature region in which the loss tangent tan δ is 0.1 or more and 0.4 or less, and a low-temperature-side temperature region in which the loss tangent tan δ is less than 0.1, and the highest temperature of the high-temperature-side temperature region is 240° C. or higher.