Semiconductive Polyolefin Composition Using Acid Catalysts
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Solution Overview
Problem
Existing semiconductive polyolefin compositions for cable layers face challenges with crosslinking, including the use of peroxides which produce unpleasant odors, require additional processing steps, and limit the maximum melt temperature, resulting in lower production speeds and potential gel or scorch particles.
Innovation Solution
A semiconductive polyolefin composition incorporating an olefin polymer with epoxy-groups and a crosslinking agent such as Lewis or Bronsted acids, which accelerates crosslinking without significant net change, reducing or eliminating the need for peroxides and allowing higher temperature processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If peroxide crosslinking is used to achieve high crosslinking degree, then crosslinking efficiency is improved, but unpleasant odor and harmful by-products are generated
Solution Approach 1:
The patent changes the chemical nature of the crosslinking agent from peroxide to Lewis acid or Bronsted acid catalyst. This parameter change in the crosslinking mechanism eliminates the formation of unpleasant odor and harmful by-products while maintaining effective crosslinking of the polyolefin composition.
Solution Approach 2:
The patent substitutes the peroxide-based free radical crosslinking mechanism with a catalyst-based ionic crosslinking mechanism using Lewis acids or Bronsted acids. This substitution replaces the harmful peroxide degradation pathway with a cleaner catalytic crosslinking process that does not generate unpleasant odor or harmful by-products.
2Reliability
If peroxide is added in a separate processing step to achieve high crosslinking degree, then crosslinking efficiency is improved, but production lead time increases
Solution Approach 1:
The patent merges the crosslinking agent with the polyolefin composition during the extrusion process. The Lewis acid or Bronsted acid catalyst is incorporated into the polymer melt along with the polyolefin and conductive filler, eliminating the need for separate peroxide addition steps and reducing production lead time while achieving effective crosslinking.
Solution Approach 2:
The patent performs preliminary mixing of the crosslinking catalyst with the polyolefin composition during extrusion. By pre-incorporating the Lewis acid or Bronsted acid catalyst into the polymer matrix before crosslinking, the process eliminates subsequent separate addition steps and reduces overall production time while ensuring uniform crosslinking.
3Manufacturing precision
If peroxide degradation temperature is maintained at about 140 °C to avoid gel particles, then crosslinking control is improved, but extruder output and production speed are limited
Solution Approach 1:
The patent changes the temperature parameter by using a catalyst system that enables crosslinking at higher temperatures than peroxide. The Lewis acid or Bronsted acid catalyst allows the extrusion and crosslinking process to proceed at temperatures above 140 °C, increasing extruder output and production speed while maintaining crosslinking control and avoiding gel particle formation.
Solution Approach 2:
The patent substitutes the temperature-limited peroxide crosslinking system with a catalyst-based crosslinking system that operates effectively at higher temperatures. This substitution removes the 140 °C temperature constraint, allowing higher extruder output and production speed while maintaining precise crosslinking control through the catalyst mechanism.
4Reliability
If organic peroxide is used to achieve high crosslinking degree, then crosslinking efficiency is improved, but a high level of undesired by-products is released after peroxide degradation
Solution Approach 1:
The patent substitutes the peroxide degradation mechanism with a catalyst-based crosslinking mechanism. The Lewis acid or Bronsted acid catalyst promotes crosslinking without undergoing degradation that releases harmful by-products, thereby eliminating the source of undesired emissions while maintaining effective crosslinking of the polyolefin composition.
Solution Approach 2:
The patent converts the harmful peroxide degradation process into a beneficial catalyst-mediated crosslinking process. By replacing peroxide with Lewis acid or Bronsted acid catalysts, the system eliminates harmful by-product formation while achieving the desired crosslinking degree, effectively turning a harmful chemical process into a clean and efficient one.
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 solution enhances crosslinkability, reduces volatile by-products, improves safety, decreases production lead time, and provides better strippability and odor control, enabling higher production speeds and improved cable quality.
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) Bronsted acids different from carboxylic acids
Data Source
AI summary
The invention relates to a semiconductive polyolefin composition comprising, - an olefin polymer (A) comprising epoxy-groups; - a conductive filter; and at least one crosslinking agent (B) which accelerates the crosslinking reaction of epoxy-groups.