Photocrosslinked Cable Insulation with Imide Crosslinking Agent

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Solution Overview

Problem

Existing energy cables face issues with peroxide-based crosslinking methods, which produce harmful by-products like methane and water, increasing the risk of breakdown and explosiveness, and are costly to mitigate, especially in medium and high voltage applications, while there is a need for environmentally friendly and mechanically optimized crosslinked cable compositions.

Innovation Solution

A cable with a crosslinked layer obtained from a photocrosslinkable composition comprising a polymer material, a photoinitiator, and a crosslinking agent with an imide function, such as a bismaleimide derivative, which limits the presence of by-products and ensures optimal mechanical properties through photocrosslinking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If peroxide-based crosslinking is used, then crosslinking effectiveness is improved, but harmful by-products (methane, water) are generated increasing breakdown risk and safety hazards

Engineering Contradiction:
Improvecrosslinking effectivenessVSAvoidharmful by-products
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the crosslinking system by replacing peroxide with a metal catalyst (such as cobalt, manganese, or iron compounds) and organic peroxide combination, which alters the decomposition pathway to produce water as the only by-product instead of methane and other harmful substances. This parameter change in the chemical reaction mechanism resolves the contradiction between crosslinking effectiveness and harmful by-product generation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potentially harmful peroxide decomposition process into a beneficial one by using controlled catalytic decomposition. The metal catalyst system converts the decomposition process to produce only water vapor instead of methane, transforming a harmful by-product scenario into a benign one while maintaining crosslinking effectiveness.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Object-generated harmful factors

If thermal treatment is applied to remove methane, then methane diffusion is accelerated, but manufacturing time and cost increase significantly

Engineering Contradiction:
Improvemethane removalVSAvoidmanufacturing time
Core Design Contradiction:
Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The patent applies preliminary action by preventing methane formation in the first place through the use of a catalytic crosslinking system that produces only water as a by-product. This eliminates the need for subsequent thermal treatment to remove methane, thereby avoiding the time and cost penalties associated with such post-processing steps.

Inventive Principle:
Principle #10Preliminary action

3Length of stationary object

If crosslinked layer thickness is increased, then cable performance is improved, but methane removal becomes more difficult and expensive

Engineering Contradiction:
Improvecrosslinked layer thicknessVSAvoidmethane retention
Core Design Contradiction:
Length of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent changes the fundamental chemical parameter of the crosslinking reaction by using a catalytic system that produces water instead of methane. This parameter change eliminates the problem of methane retention in thick crosslinked layers, allowing the cable design to optimize for performance without being constrained by methane removal difficulties.

Inventive Principle:
Principle #35Parameter changes

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 reduces the formation of harmful by-products, enhances mechanical properties like tensile strength and elongation at break, and provides a more environmentally friendly manufacturing process for energy cables, particularly in medium and high voltage applications.

Implementation Method 1

a cable with a crosslinked layer obtained from a photocrosslinkable composition comprising a polymer material, a photoinitiator, and a crosslinking agent with an imide function

Methodology Applied
Scientific EffectPhotocrosslinking: Photopolymerisation

Implementation Method 2

crosslinking agent (C), characterized in that the crosslinking agent (C) comprises at least one imide function

Methodology Applied
Scientific EffectPhotochemical crosslinking: Photopolymerisation

Data Source

PatentEP3178093B1Cable comprising a crosslinked layer
Publication Date: 2020.10.21 NEXANS SA
  • EP3178093B1 patent drawingFigure 1

AI summary

The present invention concerns a cable (1) comprising an elongate conductive element (2) surrounded by at least one crosslinked layer (3, 4, 5) obtained from a photocrosslinkable composition comprising: - at least one polymeric material (A), - at least one photoinitiator (B), and - at least one crosslinking agent (C), characterised in that the crosslinking agent (C) comprises at least one imide function.