Power Cable Insulation Blend for Recyclable Creep 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 materials lack desirable material properties.
Innovation Solution
A power cable design using an insulation layer composed of 50-84 wt% LDPE and 16-45 wt% UHMWPE, or 80-99.5 wt% XLPE with 1-20 wt% UHMWPE, providing a thermoplastic or crosslinked structure respectively, to achieve improved storage modulus at both low and high temperatures, enhancing flexibility and creep resistance.
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 chemical structure parameter of the polymer from crosslinked to non-crosslinked (thermoplastic) while compensating for mechanical strength through molecular weight control (UHMWPE with Mw ≥ 1,000,000 g/mol) and specific composition ratios (80-99.5 wt% polyethylene with 1-20 wt% UHMWPE), thereby eliminating degassing requirements while maintaining adequate mechanical properties
Solution Approach 2:
The patent creates a composite material system combining regular polyethylene and ultra-high molecular weight polyethylene (UHMWPE) in specific ratios, where the UHMWPE component provides enhanced mechanical strength and creep resistance without requiring crosslinking, thus avoiding the harmful effects of crosslinked material while maintaining structural integrity
2Stability of the object's composition
If crosslinked polymer material is used in the insulation layer, then creep resistance is improved, but recyclability is reduced
Solution Approach 1:
The patent changes the polymer network structure from chemically crosslinked to physically entangled through using UHMWPE with extremely high molecular weight (Mw ≥ 1,000,000 g/mol), which provides creep resistance through physical entanglement rather than chemical crosslinks, thereby maintaining dimensional stability while enabling recyclability through melting and reprocessing
Solution Approach 2:
The patent adopts a thermoplastic material system that can be easily processed and recycled multiple times, replacing the irreversible crosslinked structure with a reprocessable thermoplastic structure, effectively making the cable insulation recyclable and reducing waste
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 creep resistance are impaired
Solution Approach 1:
The patent develops a composite material system combining regular polyethylene and ultra-high molecular weight polyethylene (UHMWPE) in specific ratios (80-99.5 wt% polyethylene with 1-20 wt% UHMWPE), where the UHMWPE component with its extremely long chains provides enhanced creep resistance and mechanical strength while maintaining the thermoplastic nature of the material, thus achieving both ease of production and improved material properties
Solution Approach 2:
The patent changes the molecular weight parameter of the polyethylene component to ultra-high levels (Mw ≥ 1,000,000 g/mol for UHMWPE), which fundamentally improves creep resistance and mechanical strength while maintaining thermoplastic processability, thereby overcoming the limitations of conventional thermoplastic materials
Data Source
Figure 1~2
Figure 3~4
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AI summary
A power cable (1, 101) comprising: a conductor (2, 102) extending along a centre axis (C); an insulation system (5, 105) including at least a first semiconducting layer (3, 103) provided around the conductor (2, 102), and an insulation layer (4, 104) provided around the first semiconducting layer (3, 103); wherein the insulation layer (4, 104) is crosslinked or not crosslinked and comprises: ultra-high molecular weight polyethylene, UHMWPE, having a Mw of at least 1 000 000 g/mol and LDPE or XLPE.