Insulated Wire Coating Composition for Low Die Residue

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Solution Overview

Problem

The use of polyethylene and ethylene-vinyl acetate copolymers in wire coatings enhances adhesion to metals but leads to increased friction and die drool issues, affecting productivity and wire stripping, while high polyethylene content can cause surface contamination due to low molecular weight components migrating to the surface.

Innovation Solution

A resin composition combining low density polyethylene and ethylene-vinyl acetate copolymer with specific amounts of thioether compounds and fluororubber is used to reduce die residue and surface contamination, improving film-forming properties and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If polyethylene and ethylene-vinyl acetate copolymer are used as coating materials to enhance adhesion to metal conductors, then adhesion is improved, but friction increases and die drool occurs affecting productivity

Engineering Contradiction:
Improveadhesion to conductorVSAvoidproductivity
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent modifies the chemical composition parameters of the coating material by incorporating thioether compounds and fluororubber into the polyethylene-EVA system. This changes the molecular structure and surface properties of the coating, reducing friction coefficients and preventing die drool while maintaining adhesion to the conductor.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating material system combining polyethylene, ethylene-vinyl acetate copolymer, thioether compounds, and fluororubber. This multi-component composite leverages the adhesion properties of EVA, the low friction of fluororubber, and the processing benefits of thioether compounds to simultaneously achieve good adhesion and high productivity.

Inventive Principle:
Principle #40Composite materials

2Strength

If high density polyethylene is used to improve mechanical strength, then strength is improved, but low molecular weight components migrate to surface causing contamination

Engineering Contradiction:
Improvemechanical strengthVSAvoidsurface contamination
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent introduces thioether compounds and fluororubber as intermediary substances that migrate to the coating surface instead of polyethylene's low molecular weight components. These intermediaries form a stable surface layer that prevents contamination while allowing the bulk polyethylene to provide mechanical strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a surface layer composition that is different from the bulk composition. The coating material is designed so that the surface enriches in thioether and fluororubber components, creating a 'copy' or modified surface layer that provides contamination resistance while the bulk material maintains structural integrity.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS20230272198A1Resin composition, resin-coating material, insulated wire, vehicle wire harness, and method of producing insulated wire to be used in vehicle wire harness
Publication Date: 2023.08.31 FURUKAWA ELECTRIC CO LTD

AI summary

A resin composition, including the following components (A) and (B); and at least one kind of the following components (C) and (D):(A) a low density polyethylene resin;(B) an ethylene-vinyl acetate copolymer resin;(C) a thioether compound; and(D) fluororubber,in which:a content of the component (A) is 5 to 40 parts by mass and a content of the component (B) is 60 to 95 parts by mass in 100 parts by mass of a total content of the components (A) and (B), a total content of the components (C) and (D) is 0.05 to 1 part by mass with respect to 100 parts by mass of the total content of the components (A) and (B), and a proportion of a vinyl acetate component in the component (B) is 40 mass % or less.