Polyolefin Insulation with Dual-Functional Filler for DC Cable
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Solution Overview
Problem
Direct-current power cables face challenges in maintaining effective insulation due to space charges generated in the insulation layer during electric charging, leading to leakage currents, which existing technologies have not adequately addressed.
Innovation Solution
A resin composition is developed for the insulation layer, comprising a base resin with polyolefin and an inorganic filler, where the filler's surface is treated with a hydrophobic silane coupling agent and an aminosilane coupling agent, incorporating hydrophobic silyl and aminosilyl groups to enhance compatibility and electrostatic repulsion, thereby improving insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic filler is added to suppress leakage current, then insulation property is improved, but dispersibility and moldability deteriorate
Solution Approach 1:
The surface properties of the inorganic filler are modified by changing the chemical parameters of its surface groups. By introducing both hydrophobic silyl groups and aminosilyl groups, the surface characteristics are altered to achieve optimal balance between insulation performance and processability. This parameter change resolves the contradiction by making the filler surface more compatible with the polyolefin matrix while maintaining space charge suppression capability.
Solution Approach 2:
The inorganic filler surface is created as a composite structure with multiple functional groups (hydrophobic silyl groups and aminosilyl groups) working together. This composite surface structure provides both the insulation enhancement needed to suppress leakage current and the improved dispersibility required for easy manufacturing. The dual-functional surface coating acts as a bridge between the inorganic filler and polyolefin matrix.
2Reliability
If inorganic filler is added to trap space charges, then leakage current is reduced, but compatibility with polyolefin base resin deteriorates
Solution Approach 1:
The chemical composition parameters of the filler surface are modified to match the polyolefin matrix. By introducing hydrophobic silyl groups with appropriate hydrocarbon chains and aminosilyl groups, the surface polarity and chemical affinity are adjusted to improve compatibility with the non-polar polyolefin base resin. This parameter adjustment ensures uniform distribution and stable integration of the filler in the resin matrix.
Solution Approach 2:
The modified filler surface acts as an intermediary between the inorganic filler particles and the polyolefin base resin. The hydrophobic silyl groups and aminosilyl groups on the filler surface serve as chemical mediators that enhance interfacial adhesion and compatibility. This intermediary surface layer prevents aggregation of filler particles and ensures stable integration while maintaining the space charge trapping function.
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 solution significantly improves the insulation properties of the DC power cable by stabilizing the insulation layer, effectively trapping space charges and reducing leakage currents, while maintaining good dispersibility and moldability of the inorganic filler in the resin composition.
Implementation Method 1
a hydrophobic silyl group represented by the following formula (1)
Implementation Method 2
an aminosilyl group having an amino group
Implementation Method 3
space charges are generated in the insulation layer, which may cause a leakage current. Therefore, an inorganic filler may be sometimes added to the resin composition forming the insulation layer in order to suppress the leakage current during electric charging
Data Source
AI summary
A resin composition forming an insulation layer, including a base resin containing polyolefin, and an inorganic filler; wherein a surface of the inorganic filler includes a hydrophobic silyl group represented by formula (1) and an aminosilyl group having an amino group.