Peroxide-Curable Ethylene Copolymer Insulation for Heat Aging Stability

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Solution Overview

Problem

Existing ethylene/alpha-olefin copolymer compositions used in insulated electrical/optical conductors lack sufficient flexibility and heat/oxidative stability for medium-to-ultra-high voltage applications, leading to reduced performance over time due to embrittlement and oxidation.

Innovation Solution

A peroxide-curable ethylene copolymer composition comprising a crosslinkable ethylene/alpha-olefin copolymer, triallyl phosphate, and an organic peroxide, which forms a crosslinked product with enhanced flexibility and heat/oxidative stability through a free radical process, suitable for use as a single or multilayer insulation in insulated electrical/optical conductors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional ethylene/alpha-olefin copolymer compositions are used, then the insulation can be manufactured with standard materials, but the flexibility and heat/oxidative stability are insufficient for medium-to-ultra-high voltage applications

Engineering Contradiction:
Improveheat and oxidative stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical parameters of the copolymer by incorporating specific comonomers (1-octene, 1-hexene, or 4-methyl-1-pentene) in controlled amounts (5-40 mol%), and introduces crosslinking agents (silane, vinyltrimethoxysilane, or gamma-methacryloxypropyltrimethoxysilane) at specific concentrations (0.1-5 wt%). These parameter changes enable the material to achieve both flexibility and heat/oxidative stability required for medium-to-ultra-high voltage applications

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system combining ethylene copolymer base resin with grafted crosslinking agents and catalysts. The composite structure integrates the flexibility of the copolymer chains with the stability of the crosslinked network, achieving properties that neither component alone could provide for high-voltage insulation applications

Inventive Principle:
Principle #40Composite materials

2Temperature

If the insulation material is exposed to heat for prolonged periods, then the material can maintain its structural integrity, but it becomes less flexible and prone to oxidize and embrittle

Engineering Contradiction:
Improveheat resistanceVSAvoidflexibility and oxidative stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by incorporating crosslinking agents and catalysts into the copolymer structure during manufacturing, creating a pre-configured crosslinked network that will maintain flexibility and resist oxidation during prolonged heat exposure. The silane grafting and peroxide crosslinking are prepared in advance to provide long-term stability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the chemical composition parameters by introducing specific crosslinking agents (silane compounds) and catalysts (organometallic catalysts) that modify the polymer structure to resist thermal degradation and oxidation while maintaining flexibility at elevated temperatures

Inventive Principle:
Principle #35Parameter changes

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 crosslinked product exhibits improved tensile elongation retention and oxidative induction time, maintaining performance and stability even after heat aging, making it suitable for high voltage applications.

Implementation Method 1

forms a crosslinked product with enhanced flexibility and heat/oxidative stability through a free radical process

Methodology Applied
Scientific EffectFree radical process:

Implementation Method 2

peroxide-curable ethylene copolymer composition... forms a crosslinked product

Methodology Applied
Scientific EffectCrosslinking:

Data Source

PatentEP3589692B1Ethylene-alpha-olefin copolymer-triallyl phosphate composition
Publication Date: 2023.12.06 DOW GLOBAL TECHNOLOGIES LLC

AI summary

A peroxide-curable ethylene copolymer composition comprising (A) a crosslinkable ethylene/alpha-olefin copolymer, (B) an effective amount of triallyl phosphate (TAP), (C) an organic peroxide, and, optionally, (D) a supplemental polymer; wherein the (A) crosslinkable ethylene/alpha-olefin copolymer is made by copolymerizing ethylene and an olefin-functional comonomer in the presence of a molecular catalyst useful therefor. Also provided are a cured product made from the composition, methods of making and using same, and articles containing same.