Non-Crosslinking Polypropylene Cable Insulation for 90°C Heat Resistance
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Solution Overview
Problem
Existing electric cables face challenges in achieving a maximum allowable temperature of 90°C for conductors without using crosslinked polyethylene, which is costly and difficult to recycle, and also struggle with the increased heating temperature due to smaller conductor diameters.
Innovation Solution
The use of a non-crosslinking polypropylene composition, comprising reactive polypropylene and polypropylene, as the insulating material in electric cables, which eliminates the need for a crosslinking process and allows for a smaller conductor diameter while maintaining effective heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crosslinked polyethylene is used as insulating material, then heat resistance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the crosslinking process from the manufacturing sequence by using pre-crosslinked polyethylene particles as the base material. This eliminates the need for in-situ crosslinking equipment and processes, while still achieving the desired heat resistance. The crosslinking function is separated and performed beforehand during material production.
Solution Approach 2:
The polyethylene is crosslinked in advance before being used as insulating material. The pre-crosslinked polyethylene particles are prepared separately with controlled crosslinking degree, then directly incorporated into the insulating layer without requiring additional crosslinking steps during cable manufacturing.
2Volume of moving object
If conductor diameter is reduced, then cable compactness is improved, but conductor heating temperature increases
Solution Approach 1:
The patent changes the thermal parameter of the insulating material by using pre-crosslinked polyethylene with enhanced thermal stability. This allows the conductor to operate at higher temperatures without compromising insulation integrity, thereby enabling smaller conductor diameters while maintaining safe operating temperatures.
3Ease of manufacture
If polyethylene is used as insulating material, then ease of manufacture is improved, but maximum allowable temperature is limited
Solution Approach 1:
The patent changes the thermal parameter of polyethylene through pre-crosslinking, transforming it from a material suitable only for low-temperature applications to one that can withstand temperatures above 90°C. This maintains the ease of processing and manufacturing while dramatically improving the temperature rating.
4Temperature
If chemical crosslinking is used, then heat resistance is improved, but production time increases
Solution Approach 1:
The crosslinking process is performed in advance during material production, creating pre-crosslinked polyethylene particles. These particles are then directly used in the insulating layer extrusion process, eliminating the need for separate crosslinking steps and associated drying processes during cable manufacturing, thus reducing production time.
Data Source
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AI summary
Disclosed is an insulating composition which configures an insulating layer surrounding at least one conductor. The insulating composition is made of non-crosslinking polypropylene, which contains 60 to 90 weight% of reactive polypropylene and 40 to 10 weight% of polypropylene.