Epoxy-Modified Polyolefin Cable Insulation Crosslinking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cable layers in power cables, particularly those used in medium and high voltage applications, face challenges with crosslinking processes due to the use of peroxides, which result in undesirable by-products, odor issues, and limitations in production speed and temperature, leading to suboptimal performance and process inefficiencies.
Innovation Solution
The use of a polyolefin composition with epoxy-groups and a crosslinking agent such as Lewis acids or Brönsted acids, which catalyze the crosslinking reaction without substantial net change, allowing for reduced or eliminated peroxide use, higher temperature processing, and improved production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If peroxide is used as crosslinking agent, then crosslinking can be achieved, but low-molecular by-products with unpleasant odor are formed and peroxide degradation temperature limits maximum melt temperature to about 140°C
Solution Approach 1:
The patent changes the chemical parameters by replacing peroxide with epoxy groups-containing polyolefin and a catalyst system. This substitution fundamentally alters the crosslinking chemistry, eliminating peroxide degradation and its associated harmful by-products while enabling crosslinking at higher temperatures without gel formation.
Solution Approach 2:
The patent converts the typically harmful peroxide crosslinking process into a beneficial alternative by using epoxy groups that crosslink without producing low-molecular by-products. The epoxy crosslinking mechanism inherently avoids the harmful effects of peroxide decomposition, turning a problematic process into an improved one.
2Reliability
If peroxide is used for crosslinking, then crosslinking density can be achieved, but organic peroxide releases high level of undesired by-products after degradation
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating epoxy groups into the polyolefin structure and using a catalyst instead of peroxide. This parameter change achieves crosslinking density while eliminating the source of undesired by-products that comes from peroxide degradation.
3Reliability
If peroxide degradation temperature is used, then crosslinking can occur, but maximum melt temperature in extruder is limited to about 140°C which limits extruder output and production speed
Solution Approach 1:
The patent changes the temperature parameter by enabling crosslinking at temperatures above 140°C through the epoxy-catalyst system. This allows the extruder to operate at higher temperatures, increasing melt flow and extruder output, thereby improving production speed without causing premature crosslinking or gel formation.
Solution Approach 2:
The patent incorporates epoxy groups into the polyolefin composition during compounding, preparing the material in advance for high-temperature crosslinking. This preliminary action ensures that when the material is extruded at higher temperatures, crosslinking can occur controllably after extrusion rather than being limited by peroxide degradation constraints.
4Reliability
If peroxide is added into polymer before extrusion, then crosslinking can be achieved, but a separate processing step is required which increases lead time
Solution Approach 1:
The patent merges the crosslinking functionality into the polyolefin composition itself by incorporating epoxy groups during polymer synthesis or compounding. This eliminates the need for a separate peroxide addition step, as the epoxy-containing polyolefin is ready for crosslinking immediately upon extrusion, thereby reducing lead time and simplifying the processing sequence.
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
This approach enables superior crosslinkability with lower volatile by-products, improved safety, reduced processing time, and enhanced strippability properties, leading to more effective and efficient cable production with improved performance characteristics.
Implementation Method 1
at least one crosslinking agent (B) which accelerates the crosslinking reaction of epoxy-groups and which is selected from (i) Lewis acids, (ii) Brönsted acids different from carboxylic acids
Data Source
AI summary
The invention relates to a cable, comprising a conductor surrounded by one or more layer(s), wherein at least one layer comprises a polyolefin composition comprising, - an olefin polymer (A) comprising epoxy-groups; - at least one crosslinking agent (B) which accelerates the crosslinking reaction of epoxy-groups; and - optionally a conductive filler.