ETFE Copolymer Coating for Engine Oil-Resistant Electrical Wire

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Solution Overview

Problem

Existing coated electrical wires using ethylene/tetrafluoroethylene copolymers for automotive applications lack sufficient engine oil resistance, necessitating an improvement in coating materials to enhance durability under high temperature and oil exposure.

Innovation Solution

A copolymer comprising ethylene, tetrafluoroethylene, and specific monomer units with controlled crystal lamella thickness and melting point, formulated to provide enhanced engine oil resistance through a combination of low stiffness and high thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If ETFE copolymer is used as coating material for electrical wires, then weight reduction is achieved, but engine oil resistance is insufficient

Engineering Contradiction:
Improveweight of coated electrical wireVSAvoidengine oil resistance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the crystal lamella thickness (2.0-4.0 nm) and melting point (240-260°C) of the ETFE copolymer. By adjusting these physical parameters through controlled polymerization conditions and monomer composition, the coating achieves both lightweight properties and enhanced engine oil resistance, resolving the contradiction between weight reduction and reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymer system by incorporating specific fluorinated vinyl monomers (containing CF3 or OCF3 groups) into the ETFE copolymer structure. This composite approach combines the lightweight advantages of ETFE with the superior oil resistance properties of fluorinated components, achieving both weight reduction and enhanced reliability simultaneously.

Inventive Principle:
Principle #40Composite materials

2Reliability

If copolymer with low crystal lamella thickness is used, then engine oil resistance improves, but melt flow rate control becomes more difficult

Engineering Contradiction:
Improveengine oil resistanceVSAvoidmelt flow rate control
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent simultaneously optimizes multiple parameters: crystal lamella thickness (2.0-4.0 nm) for oil resistance, melting point (240-260°C) for thermal stability, and melt flow rate (10-100 g/10min) for manufacturability. By coordinating these parameter changes through controlled polymerization, the patent resolves the contradiction between improved reliability and ease of manufacture.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces local quality variations by incorporating specific fluorinated vinyl monomer units at controlled concentrations (0.1-10 mol%) within the ETFE copolymer structure. This localized modification of polymer chains achieves the desired crystal lamella thickness and oil resistance while maintaining overall melt flow characteristics suitable for manufacturing.

Inventive Principle:
Principle #3Local quality

3Temperature

If copolymer with high melting point is used, then thermal stability improves, but moldability becomes more difficult

Engineering Contradiction:
Improvemelting pointVSAvoidmoldability
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent optimizes the melting point parameter to a specific range (240-260°C) that balances thermal stability with moldability. By controlling the crystal lamella thickness and fluorinated monomer content, the patent achieves high enough melting point for thermal stability while maintaining melt flow rate sufficient for extrusion molding processes, resolving the contradiction between temperature performance and ease of manufacture.

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 copolymer achieves improved engine oil resistance by minimizing crack formation and thermal damage in the coating layer, ensuring durability and mechanical integrity under harsh conditions.

Implementation Method 1

a variety of molded products such as electrical wire sheathing, tubes, sheets, films, filaments, pump casings, fittings, packings, linings, and coatings, are produced by melt molding methods such as extrusion molding, blow molding, injection molding and rotational molding

Methodology Applied
Scientific EffectMelt molding:

Implementation Method 2

the crystal lamella thickness obtained by the small angle X-ray scattering method is at most 4.0 nm

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 3

the crystal lamella thickness obtained by the small angle X-ray scattering method is at most 4.0 nm

Methodology Applied
Scientific EffectX-ray scattering: Scattering

Implementation Method 4

it is possible to produce a coated electrical wire excellent in engine oil resistance

Methodology Applied
Scientific EffectChemical resistance:

Data Source

PatentEP4293056B1Copolymer, composition, molded body, and coated wire
Publication Date: 2026.01.28 AGC INC
  • EP4293056B1 patent drawingFigure 1~2
  • EP4293056B1 patent drawingFigure 3~4
  • EP4293056B1 patent drawingFigure 5

AI summary

To provide a copolymer capable of forming a coated electrical wire excellent in engine oil resistance, a composition, a molded product, and a coated electrical wire. The copolymer of the present invention is a copolymer comprising units based on ethylene, units based on tetrafluoroethylene, and units based on compound A represented by CH=CX(CF2)nY (wherein X and Y are each independently a hydrogen atom or a fluorine atom, and n is an integer of from 2 to 6) or compound B represented by CF2=CF-O-C3F7, wherein the crystal lamella thickness determined by the small angle X-ray scattering method is at most 4.0 nm and the melting point is at least 245°C.