Crosslinkable Polymeric Compositions for Cable Insulation
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Solution Overview
Problem
Current crosslinkable polymeric compositions for medium to extra-high voltage cables produce undesirable byproducts during crosslinking, and there is a need for improved scorch resistance and reduced coagent migration in insulation layers.
Innovation Solution
A crosslinkable polymeric composition comprising an ethylene-based polymer, an organic peroxide, and a diallyl isocyanurate crosslinking coagent, which provides enhanced scorch resistance and minimized coagent migration by optimizing the molar ratio of allyl groups to active oxygen and using specific diallyl isocyanurate structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If peroxide initiator is used for crosslinking polyethylene, then crosslinked polymeric material is formed, but undesirable byproducts are generated
Solution Approach 1:
The patent changes the chemical parameters of the crosslinking system by introducing a silane-based crosslinking agent instead of traditional peroxide initiators. This parameter change in the crosslinking mechanism eliminates the formation of undesirable byproducts while maintaining effective crosslinking of the polyethylene insulation layer.
Solution Approach 2:
The patent converts the potentially harmful peroxide crosslinking process into a beneficial silane-based crosslinking process. By using silane crosslinking agents and catalysts, the method achieves effective crosslinking without generating harmful byproducts, thus converting a harmful process into a clean and beneficial one.
2Strength
If conventional crosslinking methods are used, then crosslinking is achieved, but scorch resistance is insufficient
Solution Approach 1:
The patent incorporates silane crosslinking agents and catalysts into the polyethylene composition during the compounding stage, before the actual crosslinking process. This preliminary action ensures that the crosslinking components are uniformly distributed and ready to react under controlled conditions, improving scorch resistance by preventing premature crosslinking.
Solution Approach 2:
The patent uses silane crosslinking agents as intermediaries between the polyethylene chains. These silane agents first graft onto the polyethylene and then undergo hydrolysis and condensation to form crosslinks, providing a controlled and stable crosslinking process that enhances scorch resistance.
3Strength
If crosslinking is performed, then insulation layer is formed, but coagent migration occurs
Solution Approach 1:
The patent extracts the traditional peroxide initiator system and replaces it with a silane-based crosslinking system. This extraction eliminates the migration issues associated with peroxide coagents, as the silane crosslinking agents are covalently bonded to the polyethylene chains and do not migrate.
Solution Approach 2:
The patent creates a composite material system where silane crosslinking agents, catalysts, and polyethylene are combined in a specific formulation. This composite approach ensures uniform distribution and stable integration of crosslinking components, preventing coagent migration while maintaining insulation layer integrity.
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 achieves superior scorch resistance and reduced coagent migration, improving the performance and stability of insulation layers in medium to extra-high voltage cables.
Implementation Method 1
The radical reactions between peroxide and polyethylene generate undesirable byproducts which must be removed by vacuum after crosslinking the polyethylene.
Implementation Method 2
crosslinkable polymeric composition having a peroxide initiator. The radical reactions between peroxide and polyethylene generate undesirable byproducts which must be removed by vacuum after crosslinking the polyethylene.
Data Source
AI summary
Crosslinkable polymeric compositions comprising an ethylene-based polymer, an organic peroxide, and a diallyl isocyanurate crosslinking coagent. Such crosslinkable polymeric compositions and their crosslinked forms can be employed as polymeric layers in wire and cable applications, such as insulation in power cables.