Cable Insulation Crosslinking With Acetophenone Scavenging
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Solution Overview
Problem
The use of peroxide crosslinked ethylene-based polymer (XLPE) in HVDC cables results in the generation of acetophenone byproducts, which increase conductivity and degrade the insulation layer, requiring longer degassing times and lower DCP loading to reduce acetophenone levels, thereby compromising crosslink density and thermal resistance.
Innovation Solution
A process involving a crosslinkable polymeric composition for the insulation layer of power cables, comprising an ethylene-based polymer, dicumyl peroxide (DCP), an Si—H containing acetophenone (AP) scavenger, optional curing coagents, and anti-oxidants, which is subjected to a crosslinking procedure to form a cable core with a crosslinked insulation layer, effectively reducing AP levels and enhancing crosslink density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If low DCP loading is used to reduce acetophenone levels, then acetophenone content decreases, but crosslink density and thermal resistance deteriorate
Solution Approach 1:
The patent introduces an acetophenone scavenger as an intermediary substance that selectively reacts with and removes acetophenone byproducts from the crosslinking system. This allows the use of sufficient DCP loading to achieve high crosslink density while the scavenger simultaneously eliminates the harmful acetophenone content, resolving the contradiction between reducing byproducts and maintaining crosslink quality.
2Object-generated harmful factors
If low DCP loading is used to reduce acetophenone levels, then acetophenone content decreases, but thermal resistance deteriorates
Solution Approach 1:
The acetophenone scavenger acts as a mediator that enables the use of adequate DCP loading for high thermal resistance by removing the harmful acetophenone byproducts that would otherwise accumulate and degrade the insulation layer's thermal performance over time.
3Strength
If conventional crosslinking is used to achieve high crosslink density, then crosslink density increases, but acetophenone byproduct generation increases
Solution Approach 1:
The patent converts the harmful effect of acetophenone byproducts into a beneficial process by introducing a scavenger that selectively reacts with these byproducts. The scavenger transforms the unwanted acetophenone into harmless substances, allowing conventional high DCP loading crosslinking to proceed while eliminating the harmful effects, thus achieving both high crosslink density and low byproduct content.
4Object-generated harmful factors
If long degassing time is used to reduce acetophenone levels, then acetophenone content decreases, but production efficiency deteriorates
Solution Approach 1:
The acetophenone scavenger converts the need for prolonged degassing into a rapid chemical reaction process. Instead of relying on slow physical degassing over 30+ days, the scavenger chemically binds acetophenone during or immediately after crosslinking, reducing the degassing time to just 1-3 days and dramatically improving production efficiency while achieving the same byproduct reduction goal.
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 proposed process significantly reduces the acetophenone levels in the insulation layer, thereby improving the crosslink density and thermal resistance of the HVDC cables, allowing for shorter degassing times and higher DCP loading without compromising the cable's performance.
Implementation Method 1
Peroxide crosslinked ethylene-based polymer (XLPE) is widely used as an insulation material in industrial and municipal power transmission cables
Implementation Method 2
an Si—H containing (AP) scavenger
Data Source
AI summary
The present disclosure provides a process. In an embodiment, the process includes providing an initial cable core. The initial cable core includes (i) a conductor and (ii) an initial insulation layer. The initial insulation layer includes a crosslinkable polymeric composition composed of (a) an ethylene-based polymer composed of (1) ethylene monomer, (2) an optional α-olefin comonomer, and (3) an optional organosiloxane comonomer. The crosslinkable polymeric composition further includes (b) dicumyl peroxide (DCP), (c) an Si—H containing (AP) scavenger, (d) optional curing coagent, and (e) optional anti-oxidant. The process includes subjecting the initial cable core to a crosslinking procedure sufficient to crosslink the crosslinkable polymeric composition and form a cable core with a crosslinked insulation layer.