Ethylene Copolymer Cable Insulation With Low Dissipation Factor
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Solution Overview
Problem
Crosslinked polyethylene insulation for medium voltage, high voltage, and extra-high voltage cables faces challenges with additive sweat-out and exudation due to low additive acceptance, leading to manufacturing issues and increased dissipation factor.
Innovation Solution
A composition comprising an ethylene-based copolymer with specific comonomer content and additives, including antioxidants, organic peroxide, and a curing co-agent, which balances additive acceptance and maintains a low dissipation factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PE containing polar comonomers is used to increase additive solubility, then additive acceptance is improved, but dissipation factor increases
Solution Approach 1:
The patent changes the chemical parameters of the polyethylene base resin by incorporating polar comonomers (vinyl acetate, vinyl alcohol, carboxylic acid groups) at controlled levels to enhance additive solubility and acceptance, while carefully managing the dissipation factor through parameter optimization
Solution Approach 2:
The invention creates a composite material system combining polyethylene base resin with specific polar comonomer units and multiple additives (antioxidants, crosslinking agents, processing aids) to achieve both improved additive acceptance and acceptable dissipation factor characteristics
2Reliability
If additives are added to improve cable insulation performance, then material functionality is enhanced, but additives sweat out or exude during storage
Solution Approach 1:
The patent modifies the base resin parameters by incorporating polar comonomer units that increase polarity and additive compatibility, thereby improving additive retention and preventing sweat-out during storage while maintaining material functionality
Solution Approach 2:
The polar comonomer units act as intermediaries between the non-polar polyethylene base resin and the polar additives, improving compatibility and preventing phase separation that leads to additive exudation
3Reliability
If additives are increased to meet technical requirements, then cable performance is improved, but manufacturing challenges increase
Solution Approach 1:
The patent optimizes the polarity parameters of the base resin through controlled incorporation of polar comonomers, which improves additive compatibility and reduces manufacturing challenges such as pellet stickiness, conveying difficulties, and equipment buildup
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 composition effectively retains additives without sweat-out, improving manufacturing handling and reducing electrical losses by maintaining a low dissipation factor.
Implementation Method 1
c) from greater than 0 wt% to less than 3 wt%, based on the total weight of the composition, of an organic peroxide
Implementation Method 2
Use of PE containing polar comonomers may help to increase the solubility of such additives
Data Source
Figure 1~2
Figure 3~4
AI summary
A composition comprises a) an ethylene-based copolymer comprising units derived from ethylene and units derived from at least one comonomer of Structure I, wherein R is a C1-C2 hydrocarbyl group and R' is a C1-C4 hydrocarbyl group; b) at least one antioxidant; c) from greater than 0 wt%to less than 3 wt%of an organic peroxide, based on the total weight of the composition; d) optionally, at least one co-agent; and e) optionally, at least one tree retardant, wherein the ethylene-based copolymer has a melt temperature (Tm) (℃) and a comonomer content in moles per 100 grams ethylene-based copolymer (mol/100 g) (comonomer) that satisfies the relationship Tm＜-73.022 (comonomer) +109.3.