Thermoplastic Power Cable Insulation for Recyclable Heat Resistance
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Solution Overview
Problem
Existing power cables for medium and high voltage applications face challenges with crosslinked polymer materials, which require degassing and hinder recyclability, while thermoplastic alternatives compromise material properties.
Innovation Solution
A power cable design featuring an insulation layer composed of 40-94 wt% LDPE and 6-60 wt% PS and/or styrene block copolymer, which is thermoplastic and not crosslinked, providing improved storage modulus at low and high temperatures, and enhanced dielectric strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If crosslinked polymer material is used in the insulation layer, then heat resistance and mechanical strength are improved, but degassing is required during production and recyclability is hindered
Solution Approach 1:
The patent changes the fundamental parameter of polymer chemistry from crosslinked (thermosetting) to non-crosslinked (thermoplastic) structure. This parameter change eliminates the need for degassing during production while maintaining mechanical strength through optimized thermoplastic composition and processing conditions
Solution Approach 2:
The patent extracts and eliminates the crosslinking step from the production process. By using thermoplastic polymer material without crosslinking, the harmful degassing step is removed while still achieving the desired mechanical properties through alternative means
2Strength
If crosslinked polymer material is used in the insulation layer, then heat resistance and mechanical strength are improved, but recyclability is reduced
Solution Approach 1:
The patent changes the polymer structure parameter from crosslinked to thermoplastic, which fundamentally enables recyclability. Thermoplastic materials can be melted and reprocessed multiple times without degradation, allowing the cable insulation to be recycled and reused
Solution Approach 2:
The patent enables the recovery and reuse of polymer material through its thermoplastic nature. The insulation layer can be removed, melted, and reprocessed into new cable products, creating a circular economy approach that was not possible with crosslinked materials
3Ease of manufacture
If thermoplastic polymer material is used in the insulation layer, then recyclability and ease of production are improved, but material properties such as heat resistance are impaired
Solution Approach 1:
The patent creates a composite material system using thermoplastic polymer as the base matrix and incorporating specific additives and fillers. This composite approach allows the thermoplastic material to achieve heat resistance and mechanical strength comparable to or exceeding traditional crosslinked materials, while retaining processing advantages
Solution Approach 2:
The patent optimizes parameters such as polymer molecular weight, crystallinity, and additive composition to enhance the heat resistance of thermoplastic materials. By carefully controlling these parameters, the material achieves high-temperature stability without requiring crosslinking
4Strength
If PS and/or styrene block copolymer is added to LDPE, then storage modulus at high temperature is improved, but formulation complexity increases
Solution Approach 1:
The patent creates a composite formulation by combining LDPE with PS and/or styrene block copolymer in specific ratios. This composite approach leverages the complementary properties of each polymer: LDPE provides flexibility and processability, while PS contributes to high-temperature storage modulus and structural integrity
Solution Approach 2:
The patent optimizes the composition parameters by specifying precise weight percentage ranges for each component. This parameter optimization ensures consistent performance while simplifying the formulation process through defined ratios rather than requiring complex multi-component systems
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 cable achieves a well-balanced combination of flexibility at low temperatures and creep resistance at high temperatures, with improved recyclability and no degassing during production.
Implementation Method 1
the PS and/or styrene block copolymer forms an additional physical network within the LDPE which contributes to the advantageously high storage modulus at high temperatures
Implementation Method 2
Storage modulus is a measure of the stored energy in a material during deformation, representing the elastic, or recoverable, portion of the material's response in dynamic mechanical analysis, DMA
Data Source
AI summary
There is provided a power cable including a conductor extending along a centre axis; an insulation system including at least a first semiconducting layer surrounding the conductor, and an insulation layer surrounding the first semiconducting layer; wherein the insulation layer includes a) 40-94 wt % LDPE; and b) 6-60 wt % PS and/or styrene block copolymer, wherein the weight percentages are based on the insulation layer as a whole.