Crosslinked Insulated Wire for Heat and Water Blocking

Solution Overview

Problem

Insulating layers in insulated electric wires lack sufficient long-term heat resistance and water-stopping performance, particularly in high-temperature environments due to large heat generation during energization.

Innovation Solution

The insulated electric wire features a crosslinked polymer composition with a gel fraction of 60% or more, comprising ethylene-based copolymers or polyethylene as the main component, with a tensile elongation of 150% or more, enhancing long-term heat resistance and water-stopping performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional insulating material is used, then the wire can be manufactured easily, but the long-term heat resistance and water-stopping performance are insufficient

Engineering Contradiction:

Improvelong-term heat resistance and water-stopping performanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by crosslinking the insulating layer to transform the polymer structure from linear to networked, fundamentally changing the material's thermal and mechanical properties. This crosslinking process increases gel fraction to 30% or more, which directly improves long-term heat resistance and creep deformation resistance while maintaining manufacturability through established crosslinking technologies

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining multiple polymer components (ethylene-based copolymer, polyethylene, and other resins) in specific ratios within the insulating layer. This composite structure synergistically improves both heat resistance and water-stopping performance while allowing flexibility in manufacturing processes

Inventive Principle:

Principle #40Composite materials

2Reliability

If the insulating material is compressed and deformed to stop water, then water-stopping performance is improved, but the material deteriorates in high-temperature environments

Engineering Contradiction:

Improvewater-stopping performanceVSAvoidheat resistance

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent applies parameter changes by crosslinking the insulating layer to transform the polymer structure from linear to networked, fundamentally changing the material's thermal and mechanical properties. This crosslinking process increases gel fraction to 30% or more, which directly improves long-term heat resistance and creep deformation resistance while maintaining manufacturability through established crosslinking technologies

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies beforehand cushioning by pre-crosslinking the insulating layer before the wire is put into service. This pre-treatment creates a stable network structure that cushions against future thermal degradation and creep deformation, ensuring the material can withstand high-temperature environments and repeated compression cycles without deteriorating

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the gel fraction is increased to improve heat resistance, then long-term heat resistance is improved, but the tensile elongation decreases

Engineering Contradiction:

Improvelong-term heat resistanceVSAvoidtensile elongation

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the crosslinking degree by controlling gel fraction within the range of 30% to 90%, finding the optimal balance point where sufficient crosslinking provides heat resistance while avoiding excessive crosslinking that would cause brittleness. This parameter optimization ensures both long-term heat resistance and adequate tensile elongation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining multiple polymer components (ethylene-based copolymer, polyethylene, and other resins) in specific ratios within the insulating layer. This composite structure synergistically improves both heat resistance and water-stopping performance while allowing flexibility in manufacturing processes

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 wire exhibits improved flexibility and creep deformation resistance, effectively preventing cracking or breaking, thereby ensuring excellent long-term heat resistance and water-stopping performance.

Implementation Method 1

The insulating layer is formed of a crosslinked product of a polymer composition

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentUS12562294B2Insulated electric wire

Publication Date: 2026.02.24 SUMITOMO ELECTRIC INDUSTRIES LTD

AI summary

An insulated electric wire includes a conductor formed of a plurality of element wires twisted together, and an insulating layer covering an outer periphery of the conductor. The insulating layer is formed of a crosslinked product of a polymer composition. The polymer composition contains, as a main component, an ethylene-based copolymer, polyethylene, or a combination of an ethylene-based copolymer and polyethylene. The crosslinked product has a gel fraction of 60% or more, and the crosslinked product has a tensile elongation of 150% or more.