Crosslinkable Polyolefin Composition for Low Hot Creep Cable Insulation
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Solution Overview
Problem
Conventional coagents used in polyolefin compositions for power cables have limitations such as limited solubility, miscibility, and surface migration, leading to insufficient crosslinking, premature curing, and scorch issues, which affect the reliability and longevity of insulation layers, especially at elevated temperatures.
Innovation Solution
A crosslinkable polyolefin composition incorporating an alkenyl-functional monocyclic organosiloxane and a specific range of organic peroxide, which balances melt flow rate and hot creep performance, ensuring a stable and resilient insulation layer with improved crosslinking and reduced scorch risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional coagents are used to increase crosslinking capability, then crosslinking is improved, but solubility and miscibility are limited causing surface migration and storage issues
Solution Approach 1:
The patent changes the chemical structure parameters of the coagent by introducing silicon atoms into the molecular backbone, creating siloxane-based coagents with improved solubility and miscibility in polyolefin compositions while maintaining crosslinking capability
Solution Approach 2:
The patent creates a composite coagent structure combining organic polyolefin chains with inorganic siloxane units, achieving both good compatibility with polyolefin matrices and effective crosslinking performance
2Strength
If conventional coagents are used, then crosslinking is achieved, but premature curing and scorch occur during processing
Solution Approach 1:
The patent modifies the reactivity parameters of the coagent by adjusting the silicon-to-olefin ratio and molecular weight of the siloxane structure, creating a coagent that requires higher activation energy and thus cures more slowly and uniformly during processing
Solution Approach 2:
The siloxane structure acts as an intermediary between the polyolefin matrix and the crosslinking reaction, providing a controlled interface that prevents premature curing while enabling thorough crosslinking
3Ease of manufacture
If high melt flow rate is used for extrusion, then extrusion is enabled, but hot creep increases in the networked polymer
Solution Approach 1:
The patent optimizes the molecular weight and branching parameters of the polyolefin to achieve a balance between melt flow rate for extrusion and hot creep resistance in the crosslinked state
Solution Approach 2:
The patent creates local crosslinked regions through the coagent that provide hot creep resistance while maintaining overall processability of the material
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 a hot creep performance of less than 175% after 15 minutes at 200°C, significantly reducing the risk of insulation layer sagging and deformation, thereby enhancing the reliability and longevity of power cables.
Implementation Method 1
The networked polymer is made by curing a crosslinkable polymer after the crosslinkable polymer has been extruded
Implementation Method 2
coagents that is an alkenyl-functional monocyclic organosiloxane
Data Source
AI summary
A crosslinkable polyolefin composition comprising an ethylene/alpha-olefin copolymer elastomer having a melt index from 0.6 to 6.2 grams per 10 minutes, a crosslinking effective amount of an alkenyl-functional monocyclic organosiloxane, and from 0.29 to 0.44 wt% of an organic peroxide; products made therefrom; methods of making and using same; and articles containing same.