Polymer Composition Water Tree Resistance via Masterbatch

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Solution Overview

Problem

Polyolefin-based electric power cables suffer from shortened service life due to water treeing, a phenomenon where defects form under electrical stress in humid environments, leading to reduced breakdown strength and potential electric failure.

Innovation Solution

A process involving the creation of a masterbatch with water tree retardant additives and a carrier polymer, blended with LDPE, to produce a polymer composition that enhances the homogeneity and resistance to water treeing, maintaining excellent electric breakdown strength even after wet aging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If water tree retardant additives are added directly to polyolefin after polymerization, then water tree resistance is improved, but additive distribution homogeneity deteriorates

Engineering Contradiction:

Improvewater tree resistanceVSAvoidadditive distribution homogeneity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent uses a masterbatch as an intermediary carrier to deliver water tree retardant additives to the polyolefin. The masterbatch contains pre-dispersed additives in a carrier resin, which then distributes them uniformly during the compounding process. This intermediary approach solves the homogeneity problem while maintaining water tree resistance improvement.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The additives are pre-dispersed and pre-mixed into the masterbatch before being incorporated into the final polyolefin product. This preliminary action ensures uniform distribution is achieved during the masterbatch production stage, preventing aggregation and ensuring consistent additive delivery throughout the final product.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If high concentrations of water tree retardant additives are used, then water tree resistance is improved, but processing difficulty increases

Engineering Contradiction:

Improvewater tree resistanceVSAvoidprocessing difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the concentration parameter by using relatively low levels of WTR additives (0.01-5 wt%) in the masterbatch, which when compounded into the final product results in optimal concentrations (0.1-5 wt%) without causing processing difficulties. This parameter optimization balances effectiveness with manufacturability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The masterbatch acts as a mediator that facilitates easy incorporation of additives during standard compounding processes. The pre-dispersed nature of additives in the masterbatch eliminates the need for special handling or high-shear mixing that would be required for concentrated additive additions.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If water tree retardant additives are added as such without carrier medium, then additive efficiency is improved, but distribution homogeneity deteriorates

Engineering Contradiction:

Improveadditive efficiencyVSAvoiddistribution homogeneity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The masterbatch serves as an intermediary carrier medium that maintains additive efficiency while ensuring distribution homogeneity. The carrier resin in the masterbatch protects the additives and facilitates their uniform dispersion during compounding, preventing both aggregation and loss of effectiveness.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite masterbatch material combining the carrier resin with water tree retardant additives. This composite structure allows the additives to be delivered efficiently while the carrier resin ensures uniform distribution throughout the final polyolefin product during the compounding process.

Inventive Principle:

Principle #40Composite materials

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 polymer composition effectively prevents water treeing, maintaining electric breakdown strength comparable to cables where additives were directly compounded post-polymerization, without sacrificing performance.

Implementation Method 1

blending the masterbatch obtained from step a) with at least one LDPE polymer (A) to obtain said polymer composition

Methodology Applied

Scientific EffectMixing:

Data Source

PatentEP2379624B1Masterbatch and process for preparing a polymer composition

Publication Date: 2019.09.25 BOREALIS AG

AI summary

The present invention relates to a process for preparing a polymer composition by using a masterbatch, as well as a process, wherein said polymer composition is used for preparing an article, preferably a cable.. Also a masterbatch, a polymer composition comprising the masterbatch, and an article, preferably a cable, comprising the polymer composition are provided.