Uncrosslinked Polyethylene Power Cable Insulation
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Solution Overview
Problem
Existing power cable insulators made from crosslinked polyethylene suffer from environmental pollution due to non-recyclability and have limitations in heat resistance and durability, while uncrosslinked polyethylene is restricted due to inferior heat resistance, and the crosslinking process is inefficient with high pressure and temperature requirements, leading to production issues and tracking failures.
Innovation Solution
A composition comprising linear medium-density polyethylene with an α-olefin comonomer and high-density polyethylene, along with additives and carbon black, to enhance heat resistance, electrical properties, and recyclability, allowing for improved tracking resistance and environmental sustainability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crosslinked polyethylene is used to improve heat resistance and durability, then long-term heat resistance and durability are improved, but environmental pollution increases due to non-recyclability
Solution Approach 1:
The invention changes the chemical structure parameters of polyethylene by introducing specific comonomers (α-olefins with 4-12 carbon atoms) and controlling molecular weight distribution (2-30) and density (0.91-0.94 g/cm³), enabling uncrosslinked polyethylene to achieve heat resistance comparable to crosslinked types while maintaining recyclability
Solution Approach 2:
The invention creates a composite resin system combining multiple polyethylene types with different molecular weights and densities, where each component contributes specific properties: high-density component provides structural stability and heat resistance, while lower-density components provide flexibility and processability, achieving overall performance comparable to crosslinked polyethylene
2Object-generated harmful factors
If uncrosslinked polyethylene is used to avoid environmental pollution and reduce cost, then recyclability and cost are improved, but heat resistance deteriorates
Solution Approach 1:
The invention systematically adjusts critical parameters including melt index (0.3-5.0 g/10min), molecular weight distribution (2-30), and comonomer content to optimize the balance between processability and heat resistance, enabling uncrosslinked polyethylene to withstand cable operating temperatures without degradation
Solution Approach 2:
The invention combines multiple polyethylene resins with complementary properties in specific ratios, where the blend synergistically enhances heat resistance while maintaining the recyclability and cost advantages of uncrosslinked structures
3Reliability
If crosslinking process is used to improve heat resistance, then heat resistance is improved, but productivity decreases due to high pressure and temperature requirements
Solution Approach 1:
The invention extracts and eliminates the crosslinking step from the production process entirely, using specially formulated uncrosslinked polyethylene resins that inherently provide the required heat resistance, thereby simplifying the manufacturing process and improving productivity
Solution Approach 2:
The invention changes the fundamental approach from post-production crosslinking to pre-formulation of heat-resistant uncrosslinked resins through controlled molecular architecture, eliminating the need for high-pressure, high-temperature crosslinking equipment and processes
4Reliability
If crosslinking process is used to improve heat resistance, then heat resistance is improved, but product uniformity deteriorates due to nonuniform crosslinkage
Solution Approach 1:
The invention removes the crosslinking process that causes nonuniform structure, replacing it with uniformly formulated uncrosslinked resins that exhibit consistent properties throughout the product, eliminating variability associated with crosslinkage distribution
Solution Approach 2:
The invention emphasizes homogeneous resin formulation with controlled molecular weight distribution and uniform comonomer distribution, ensuring consistent material properties throughout the extruded cable insulation without the nonuniformity inherent in crosslinked structures
5Reliability
If crosslinking process is used to improve heat resistance, then heat resistance is improved, but production cost increases due to complex process requirements
Solution Approach 1:
The invention eliminates the entire crosslinking process step, including associated equipment, energy consumption, and operational complexity, replacing it with a simple extrusion process using pre-formulated heat-resistant uncrosslinked resins
Solution Approach 2:
The invention shifts the complexity from the manufacturing process to the material formulation stage, where heat resistance is built into the resin structure itself through controlled molecular architecture, allowing simple extrusion processing
Data Source
AI summary
Disclosed is uncrosslinked linear medium-density polyethylene resin composition for a power cable, which is applicable to an insulating layer, a semi-conducting layer or a sheath layer. Specifically, the uncrosslinked polyethylene composition includes: 100 parts by weight of a polymer comprising a linear medium-density polyethylene resin comprising an α-olefin having 4 or more carbon atoms as a comonomer and having a melt index of 0.6-2.2 g/10 min (at 190 ℃ under a load of 5 kg), a differential scanning calorimetry (DSC) enthalpy of 130-190 joule/g and a molecular weight distribution of 2-30; and 0.1 to 10 parts by weight of one or more additive(s) selected from a flame retardant, an oxidation stabilizer, a UV stabilizer, a heat stabilizer and a process aid.