Non-crosslinked Polyethylene Composition for Power Cable Insulation
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Solution Overview
Problem
The existing crosslinked polyethylene resins used in power cables have limitations in recyclability, processability, and environmental impact due to high production costs and poor AC dielectric breakdown strength, space charge distribution, and water tree resistance, while non-crosslinked polyethylene resins lack sufficient heat resistance and durability.
Innovation Solution
A non-crosslinked polyethylene composition for power cables is developed, incorporating a linear polyethylene resin with α-olefin comonomers, low-density polyethylene, and additives such as oxidation stabilizers and polar groups to enhance heat resistance, processability, and electrical properties, allowing for use in insulating, semi-conducting, and sheath layers without crosslinking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crosslinked polyethylene resin is used to improve heat resistance and durability, then long-term heat resistance and durability are improved, but recyclability is lost and environmental pollution increases
Solution Approach 1:
The patent changes the chemical structure parameters of polyethylene by incorporating specific comonomers (ethylene/propylene, ethylene/butene, ethylene/octene copolymers) and controlling molecular weight distribution (2.0-5.0) and density (0.910-0.940 g/cm³) to achieve thermoplastic properties with enhanced heat resistance, eliminating the need for crosslinking while maintaining reliability
Solution Approach 2:
The patent creates a composite resin system combining multiple polyethylene types with different properties (HDPE, LLDPE, LDPE) in specific ratios to achieve a balance of processability, heat resistance, and electrical properties, resulting in a thermoplastic material that replaces crosslinked polyethylene
2Ease of manufacture
If non-crosslinked polyethylene resin is used to improve recyclability and reduce environmental pollution, then recyclability is improved, but heat resistance and durability are significantly insufficient
Solution Approach 1:
The patent modifies the parameters of non-crosslinked polyethylene by controlling comonomer content (5-20 mol%), molecular weight distribution (2.0-5.0), and density (0.910-0.940 g/cm³) to enhance heat resistance while maintaining thermoplastic recyclability, achieving both environmental friendliness and reliability
Solution Approach 2:
The patent introduces local structural modifications through comonomer incorporation at specific positions in the polymer chain, creating regions with enhanced thermal stability while preserving the overall thermoplastic nature and processability of the material
3Reliability
If organic peroxide crosslinking method is used to achieve crosslinking, then crosslinking is completed, but high-pressure and high-temperature conditions are required and productivity is significantly low
Solution Approach 1:
The patent extracts and eliminates the crosslinking step entirely from the manufacturing process by developing a thermoplastic resin formulation that achieves the desired performance without chemical crosslinking, thereby removing the bottleneck in productivity
Solution Approach 2:
The patent segments the resin into multiple components with different functions (base polyethylene, comonomers, additives) that can be independently optimized and processed, allowing for simplified manufacturing without the need for post-polymerization crosslinking steps
4Object-affected harmful factors
If crosslinking process is applied to remove bubbles formed during crosslinking, then bubble removal is achieved, but high pressure of 5 atm or more should be applied and process complexity increases
Solution Approach 1:
The patent converts the potential harm of bubble formation into a benefit by using a thermoplastic formulation that allows bubbles to be easily removed during the extrusion process itself through pressure control and material flow, eliminating the need for additional high-pressure treatment steps
Solution Approach 2:
The patent performs preliminary action by controlling the resin formulation and processing conditions during extrusion to prevent bubble formation in the first place, using appropriate screw design and temperature control to ensure homogeneous material flow without void formation
Data Source
AI summary
Provided is a non-crosslinked polyethylene composition for a power cable in which crosslinked polyethylene widely used in the world as an existing insulator for a power cable is replaced with a non-crosslinked polyethylene resin, and more particularly, a non-crosslinked polyethylene composition for a power cable having excellent processability, AC dielectric breakdown strength, space charge distribution, and water tree resistance.