Moisture-Curable Semiconductive Blend With Lower Carbon Black Loading
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Solution Overview
Problem
Existing semiconductive materials for power cables face issues with high moisture uptake and electrical performance, particularly at elevated temperatures, due to the inclusion of ultra-low wettability carbon blacks and other materials that compromise mechanical and electrical properties.
Innovation Solution
A moisture-curable semiconductive formulation comprising a polyethylene-based polymer blend with a conventional carbon black, excluding ethylene/hydrolyzable silane/polar comonomer terpolymer and polyorganosiloxane, which achieves low volume resistivity and mechanical stability through a crosslinked network, enabling reduced carbon black content without sacrificing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultra-low wettability carbon black is used to achieve low volume resistivity, then electrical performance is improved, but moisture uptake increases and mechanical properties deteriorate
Solution Approach 1:
The patent removes ultra-low wettability carbon black from the formulation and replaces it with conventional carbon black combined with a moisture-curable polymer system. This extraction eliminates the harmful moisture uptake effect while maintaining electrical performance through alternative mechanisms.
Solution Approach 2:
The patent creates a composite material system combining conventional carbon black with moisture-curable polymers (silane-modified polyethylene and polyol). This composite approach achieves low volume resistivity through the synergistic interaction of carbon black conductive network and polymer matrix, without relying on ultra-low wettability carbon black.
2Reliability
If conventional carbon black is used to achieve low volume resistivity, then electrical performance is improved, but carbon black content must be high which increases material cost and processing difficulty
Solution Approach 1:
The patent develops a composite formulation where conventional carbon black works synergistically with moisture-curable polymers to achieve effective conductivity at lower carbon black loadings. The polymer matrix enhances the conductive network efficiency, reducing the quantity of carbon black needed.
Solution Approach 2:
The patent changes the chemical and physical parameters of the polymer matrix through moisture curing, creating a crosslinked network that improves carbon black dispersion and conductive network formation. This allows lower carbon black content to achieve the same electrical performance.
3Strength
If crosslinking agents with functional end groups are used to achieve mechanical stability, then mechanical properties are improved, but moisture uptake increases
Solution Approach 1:
The patent removes polyorganosiloxane crosslinking agents with functional end groups from the formulation. Instead, it uses moisture-curable polymers that crosslink through hydrolysis and condensation of silane groups incorporated into the polymer backbone, eliminating the harmful moisture uptake effect.
Solution Approach 2:
The patent replicates the crosslinking function achieved by traditional crosslinking agents through an alternative mechanism: moisture-curable silane groups within the polymer structure that crosslink upon exposure to moisture, providing mechanical stability without requiring separate crosslinking agents.
4Ease of manufacture
If ethylene/hydrolyzable silane/polar comonomer terpolymer is used to achieve moisture curability, then curability is improved, but electrical and mechanical properties deteriorate
Solution Approach 1:
The patent removes ethylene/hydrolyzable silane/polar comonomer terpolymer from the formulation and replaces it with a blend of silane-modified polyethylene and polyol. This alternative moisture-curable system maintains electrical and mechanical properties while achieving curability.
Solution Approach 2:
The patent creates a composite polymer blend where silane-modified polyethylene provides moisture curability through silane hydrolysis and condensation, while polyol contributes to mechanical properties and crosslinking. This composite system achieves curability without sacrificing electrical and mechanical performance.
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 formulation provides excellent electrical and mechanical performance, including low volume resistivity at 90° C. and 130° C., high elongation, and surface smoothness, surpassing the performance of ultra-low wettability carbon blacks, while maintaining geometry under high temperature operations.
Implementation Method 1
an ethylene/(alkenyl-functional hydrolyzable silane)/(optional olefinic hydrocarbon) copolymer (moisture curable)
Implementation Method 2
crosslinked semiconductive product, made therefrom by moisture curing
Data Source
AI summary
A moisture-curable semiconductive formulation consisting essentially of a polyethylene-based polymer blend (uncured) and a conventional carbon black. The polyethylene-based polymer blend comprises a mixture of an ethylene/(alkenyl-functional hydrolyzable silane)/(optional olefinic hydrocarbon) copolymer and an ethylene/unsaturated carboxylic ester copolymer that is free of moisture curable groups. We also discovered methods of making and using same, a moisture-cured semiconductive product made therefrom, and articles containing or made from same.