Siloxane Oligomer Cross-Linked Layer for Cable Insulation

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Solution Overview

Problem

Conventional medium and high voltage power cables rely on lead-based compounds for water absorption control and electrical insulation, which are not environmentally friendly and lead to significant dielectric losses over time.

Innovation Solution

A cross-linked layer using a siloxane oligomer as a protective agent in a crosslinkable polymer composition, replacing lead-based compounds, ensures excellent mechanical and electrical properties, including limited water absorption and dielectric losses, without using lead-based compounds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lead-based compounds are used as protective agents in cross-linked layers, then water absorption control and electrical insulation are improved, but environmental compatibility deteriorates

Engineering Contradiction:
Improveelectrical insulationVSAvoidenvironmental compatibility
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter by replacing lead-based compounds with siloxane oligomers, specifically using compounds with Si-O-Si backbone structures and controlled molecular weights to achieve comparable electrical insulation properties without environmental harm

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite protective system combining siloxane oligomers with cross-linkable polymer matrices, where the siloxane components provide water resistance and electrical insulation while the polymer matrix provides structural integrity, achieving performance without lead-based compounds

Inventive Principle:
Principle #40Composite materials

2Reliability

If lead-based compounds are used as protective agents in cross-linked layers, then water absorption control is improved, but environmental compatibility deteriorates

Engineering Contradiction:
Improvewater absorption controlVSAvoidenvironmental compatibility
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical structure parameters by introducing siloxane oligomers with specific Si-O-Si bond configurations and molecular weights (typically 2-20 monomer units) that provide hydrophobicity and water absorption control comparable to lead-based compounds but without environmental toxicity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the protective mechanism from lead-based compound chemistry to siloxane-based chemistry, where the Si-O-Si bond structure and associated hydrophobic groups provide water resistance through different chemical mechanisms that are environmentally benign

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If conventional protective agents are used in cross-linked layers, then manufacturing simplicity is maintained, but dielectric losses increase over time

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddielectric losses
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent optimizes the molecular weight and structural parameters of siloxane oligomers to balance processing characteristics with long-term electrical performance, using compounds that remain manageable during manufacturing while providing stable dielectric properties with minimal losses over the cable lifetime

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent develops composite formulations where siloxane oligomers are integrated into cross-linkable polymer matrices, creating a synergistic system that maintains manufacturing simplicity through conventional processing methods while achieving superior long-term dielectric stability and reduced energy losses

Inventive Principle:
Principle #40Composite materials

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 cross-linked layer provides stable electrical insulation with dielectric losses of at most 0.020 at 130°C, even after immersion in water for extended periods, ensuring long-term performance and environmental sustainability.

Implementation Method 1

the siloxane oligomer is intended to control and reduce water absorption in the electrical device

Methodology Applied
Scientific EffectHydrophobic interaction: Hydrophobe

Implementation Method 2

the crosslinked layer of the invention has dielectric losses, evaluated by the tangent value delta(tan δ) according to the ASTM D150 standard: of at most 0.020 at 130°C

Methodology Applied
Scientific EffectDielectric property: Dielectric

Implementation Method 3

a crosslinked layer obtained from a crosslinkable polymer composition comprising a polymer material and a protective agent

Methodology Applied
Scientific EffectCovalent bonding: Chemical Bonding

Data Source

PatentEP3257057A1Electrical device comprising a cross-linked layer
Publication Date: 2017.12.20 NEXANS SA

AI summary

The present invention relates to an electrical device (1, 20, 30) comprising a cross-linked layer (3, 4, 5) obtained from a cross-linkable polymer composition comprising a polymer and a protecting agent, characterised in that the protecting agent is at least one siloxane oligomer.