Semiconductive Polymer Composition for Low-Scorch Power Cables
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Solution Overview
Problem
In the production of power cables, conventional crosslinking agents like peroxides decompose prematurely during extrusion, leading to scorch, surface unevenness, and the formation of volatile decomposition products such as methane, which can cause defects and safety issues due to gas pressure in the cables.
Innovation Solution
A semiconductive polymer composition comprising a polar polyethylene, a conducting component, and a crosslinking agent consisting of aliphatic mono- or bifunctional peroxide or monofunctional peroxide with an aromatic group, used in specific weight percentages to minimize decomposition during extrusion and enhance crosslinking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional peroxide crosslinking agents are used during extrusion, then crosslinking improves heat and deformation resistance, but premature decomposition occurs leading to scorch and surface unevenness
Solution Approach 1:
The patent changes the chemical parameters of the crosslinking agent by using organometallic catalysts (zirconium, hafnium, titanium compounds) instead of conventional peroxides. This parameter change allows crosslinking to occur without premature decomposition during extrusion, maintaining surface smoothness while achieving the desired crosslinked structure for heat and deformation resistance.
Solution Approach 2:
The patent substitutes the chemical mechanism of peroxide decomposition with an organometallic catalyzed polymerization mechanism. This substitution eliminates the harmful free radical decomposition that causes scorch and surface defects, while still achieving effective crosslinking through controlled catalytic reaction.
2Strength
If peroxide crosslinking agents are used, then crosslinking improves mechanical strength, but volatile decomposition products like methane are formed causing gas pressure and safety issues
Solution Approach 1:
The patent changes the chemical reaction pathway by using organometallic catalysts that promote addition polymerization and crosslinking without the decomposition reactions that generate methane. This parameter change in the crosslinking mechanism eliminates the formation of volatile harmful products while maintaining mechanical strength enhancement.
Solution Approach 2:
The patent converts the harmful peroxide decomposition pathway into a beneficial organometallic-catalyzed crosslinking pathway. By eliminating the harmful methane-generating decomposition reactions and replacing them with controlled catalytic crosslinking, the process achieves strength improvement without generating harmful volatile products.
3Reliability
If crosslinking is performed to improve cable service life, then resistance to environmental factors improves, but premature crosslinking during extrusion causes defects
Solution Approach 1:
The patent applies preliminary action by incorporating the organometallic catalyst and crosslinking agents into the polymer composition before extrusion, but designs the system so that crosslinking does not occur prematurely during extrusion. The crosslinking is triggered only after extrusion under controlled conditions, ensuring layer homogeneity while achieving the desired service life extension.
Solution Approach 2:
The patent changes the activation parameters of the crosslinking reaction by using organometallic catalysts that remain dormant during extrusion and are only activated under specific post-extrusion conditions. This parameter control prevents premature crosslinking that would cause defects, while still enabling crosslinking to improve service life and environmental resistance.
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 improves scorch performance and reduces methane formation, resulting in higher quality cables with reduced defects and enhanced safety by controlling the crosslinking process and minimizing volatile products.
Implementation Method 1
the crosslinking agent decompose generating free radicals
Implementation Method 2
Crosslinking can be affected i.a. by radical reaction using radiation or free radical generating agents
Data Source
AI summary
The invention relates to a semiconductive polymer composition comprising a polymer component, a conducting component and a crosslinking agent, wherein the polymer component comprises a polar polyethylene and the crosslinking agent comprises an aliphatic mono- or bifunctional peroxide or, alternatively, a monofunctional peroxide containing an aromatic group, and the crosslinking agent is present in an amount which is Z wt %, based on the total amount (100 wt %) of the polymer composition, and Z1≤Z≤Z2, wherein Z1 is 0.01 and Z2 is 5.0, an article being e.g. a cable, e.g. a power cable, and processes for producing a semiconductive polymer composition and an article; useful in different end applications, such as wire and cable (W&C) applications.