Propylene Polymer Cable Extrusion with Particle Selection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Medium and high voltage cables face challenges with crosslinked polyolefin insulating layers, including non-recyclability, limited production speed, risk of scorch phenomena due to XLPE particle formation, and contamination issues with polypropylene materials, which affect electrical properties and reliability.

Innovation Solution

A method involving an extruder device with a barrier screw and extruder head that controls and selects thermoplastic polymer particles based on attributes like color, shape, and size, combining them with a dielectric liquid to form an extruded thermoplastic layer around the conductive element, ensuring high-quality insulation without contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If crosslinked polyolefin (XLPE) is used for insulating layer, then temperature resistance above 70°C is achieved, but production speed is limited due to long crosslinking time

Engineering Contradiction:

Improvetemperature resistanceVSAvoidproduction speed

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The patent changes the fundamental parameter of the insulating material from crosslinked polyolefin to thermoplastic polyolefin, eliminating the need for crosslinking process. This allows the cable to operate at temperatures above 70°C through material selection rather than chemical crosslinking, thereby enabling high-speed continuous production without time-consuming crosslinking tunnels.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If crosslinking process is applied to achieve satisfactory crosslinking rate, then temperature resistance is improved, but manufacturing time increases significantly

Engineering Contradiction:

Improvecable performance at high temperatureVSAvoidcrosslinking time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts and eliminates the crosslinking process from the manufacturing sequence by using thermoplastic materials that achieve high-temperature resistance through their inherent material properties rather than post-extrusion crosslinking, thereby removing the time-consuming step from the production line.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If polypropylene particles are used for insulating layer, then electrical properties are improved, but contaminating particles cause detrimental effects on cable reliability

Engineering Contradiction:

Improveelectrical propertiesVSAvoidcontaminating particles

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses thermoplastic polyolefin particles as a substitute material that is inherently more resistant to contamination issues. While polypropylene offers good electrical properties, the thermoplastic polyolefin provides comparable or superior performance with significantly reduced sensitivity to contaminating particles, making the material more forgiving and reliable in practical applications.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Reliability

If XLPE particles are formed during extrusion, then crosslinking is achieved, but homogeneity is reduced due to scorch phenomenon

Engineering Contradiction:

Improvecrosslinking effectivenessVSAvoidhomogeneity of insulating layer

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

Instead of forming crosslinked particles during extrusion (which causes scorch and heterogeneity), the patent inverts the approach by using thermoplastic materials that maintain homogeneity during extrusion and achieve the desired high-temperature resistance through material selection rather than in-process crosslinking.

Inventive Principle:

Principle #13The other way round (Inversion)

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 method enhances electrical properties of the insulating layer while maintaining reasonable production costs and preventing defects, improving the reliability and efficiency of medium and high voltage cables.

Implementation Method 1

A method for manufacturing an electrical cable by extrusion of a solid particle composition of a propylene polymer

Methodology Applied

Scientific EffectExtrusion: Extrusion

Implementation Method 2

combining them with a dielectric liquid to form an extruded thermoplastic layer

Methodology Applied

Scientific EffectMixing:

Data Source

PatentEP4249207A1Method for manufacturing an electrical cable by extrusion of a solid particle composition of a propylene polymer comprising selecting solid particles as a function of attribute

Publication Date: 2023.09.27 NEXANS SA

Figure 1~2
Figure 3

AI summary

The invention relates to a method for manufacturing an electrical cable comprising at least one elongated electrically conductive element and at least one extruded thermoplastic layer surrounding said elongated electrically conductive element, characterized in that it comprises at least the following steps: i) a step of controlling at least one attribute of at least one thermoplastic polymer in the form of solid particles selected from a propylene homopolymer and a propylene copolymer, ii) a step of selecting solid particles of said at least one polymer according to said at least one attribute, iii) a step of introducing a composition comprising said solid particles of said at least one thermoplastic polymer from step ii) into a feed zone of a barrier screw located at the inlet of an extruder,and iv) an application step at the extruder head of the composition from step iii) around the elongated electrically conductive element.