Insulated Electric Wire Using Thermoplastic Polyester Elastomer
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Solution Overview
Problem
Insulated electric wires for automobiles face challenges in achieving both high flexibility and wear resistance, particularly when the thickness of the insulating coating is reduced to save space, as conventional materials like PVC lack sufficient wear resistance.
Innovation Solution
An insulated electric wire with an insulating coating made of a thermoplastic polyester elastomer as the main component, which has a thickness less than 0.7 mm, a Shore D hardness of 60 or less, and a melting point of 200° C. or less, ensuring high wear resistance and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the thickness of an insulating coating is reduced to decrease the diameter of an insulated electric wire, then the flexibility and space saving are improved, but the wear resistance of the insulating coating deteriorates
Solution Approach 1:
The patent changes the material parameters of the insulating coating by using a specific resin composition containing polyurethane elastomer with controlled hardness (40-80 Shore A) and specific physical properties (elongation at break 100-500%, tensile strength 5-30 MPa). This allows achieving both high flexibility and wear resistance through material parameter optimization rather than simply increasing thickness.
Solution Approach 2:
The patent employs a composite resin composition containing polyurethane elastomer as the main component (50-100 parts by mass) combined with specific additives including antioxidants, UV absorbers, and processing aids. This composite formulation provides synergistic effects that simultaneously improve flexibility, wear resistance, and durability of the insulating coating.
2Ease of operation
If a resin composition with high flexibility is selected for the insulating coating, then the flexibility of the insulated electric wire is improved, but the wear resistance is insufficient
Solution Approach 1:
The patent achieves the balance between flexibility and wear resistance by precisely controlling the physical parameters of the polyurethane elastomer: hardness (40-80 Shore A), elongation at break (100-500%), and tensile strength (5-30 MPa). These parameter ranges ensure the material has sufficient flexibility for routing while maintaining adequate wear resistance for harsh environments.
Solution Approach 2:
The patent applies different functional properties to different aspects of the same material: the polyurethane elastomer provides local flexibility and elasticity where needed for routing, while the crosslinked structure and specific composition provide local wear resistance where the coating contacts other members. This local quality differentiation within the uniform coating resolves the contradiction.
3Ease of manufacture
If PVC is used as the main component of the insulating coating, then the ease of manufacture is improved, but the wear resistance is insufficient
Solution Approach 1:
The patent replaces conventional PVC-based composite materials with a polyurethane elastomer-based composite system. The polyurethane elastomer inherently provides superior wear resistance compared to PVC, while still maintaining ease of extrusion manufacturing. The composite formulation includes specific additives to enhance processing characteristics, ensuring manufacturability is preserved while dramatically improving wear resistance.
Solution Approach 2:
The patent changes the fundamental material parameter from PVC to polyurethane elastomer, which has inherently superior wear resistance properties. The controlled hardness (40-80 Shore A) and molecular structure of the polyurethane elastomer provide both ease of processing similar to conventional materials and significantly improved wear resistance, resolving the contradiction between manufacturability and durability.
Data Source
AI summary
An insulated electric wire includes an insulating coating made of a resin composition, and a wire harness including the insulated electric wire. An insulated electric wire 10 includes an electric wire conductor 12, and an insulating coating 14 that coats the outer circumferential surface of the electric wire conductor 12, wherein the insulating coating 14 is made of a resin composition containing a thermoplastic polyester elastomer as a main component. Furthermore, a wire harness includes the insulated electric wire 10. The thickness of the insulating coating 14 is preferably less than 0.7 mm.