Extruded Insulated Rectangular Wire for Peel-Free Bending
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Solution Overview
Problem
Existing methods for producing rectangular wires with insulating coating materials face issues of low productivity, poor surface smoothness, and poor conformability of the film to the conductor, leading to wrinkles or peeling during bending deformation.
Innovation Solution
A rectangular wire with a film of insulating coating material formed by extrusion molding, using a fluorine-containing copolymer with specific properties, including a melt flow rate, thickness uniformity, and adhesion, to ensure the film adheres to the conductor without peeling during bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If powder coating method is used to form insulating coating on rectangular conductor, then insulation properties can be achieved, but productivity is reduced due to required powder preparation and firing steps
Solution Approach 1:
The invention uses melting and solidification phase transition of the fluororesin composition to form the insulating coating. The composition is applied in molten state and solidifies upon cooling, eliminating the need for powder preparation and firing steps while maintaining excellent insulation properties and significantly improving productivity
Solution Approach 2:
The invention replaces the thermal processing mechanism (firing) with a simple cooling solidification process. The molten fluororesin composition solidifies naturally after application, substituting the complex mechanical firing system with a passive thermal cooling process that enhances productivity
2Reliability
If powder coating method is used to form insulating coating, then insulation properties can be achieved, but surface smoothness of the film is reduced
Solution Approach 1:
The invention changes the physical state parameter of the coating material from powder to molten liquid. This parameter change allows the coating to flow and conform smoothly to the conductor surface, then solidify into a smooth film, achieving both excellent insulation properties and high surface smoothness
3Reliability
If insulating coating material is applied to rectangular conductor, then insulation is provided, but conformability during bending deformation is poor causing wrinkles or peeling
Solution Approach 1:
The invention uses a fluororesin composition that forms a flexible film capable of conforming to the rectangular conductor during bending deformation. The molten state allows the coating to flow and adapt to shape changes, and the resulting solid film maintains flexibility and adhesion, preventing wrinkles and peeling while providing reliable insulation
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 solution results in a highly productive rectangular wire with excellent surface smoothness and conformability of the insulating coating material, enhancing the film's adhesion and preventing peeling during bending deformation.
Implementation Method 1
a film of an insulating coating material formed by extrusion molding that directly covers the entire circumferential direction of the rectangular conductor
Implementation Method 2
extruding a melted fluorine-containing copolymer from the die around the rectangular conductor; thereby coating around the rectangular conductor with the melted fluorine-containing copolymer and forming the insulating coating material
Data Source
AI summary
The present invention pertains to a rectangular wire including:a rectangular conductor; anda film of an insulating coating material formed by extrusion molding that directly covers the entire circumferential direction of the rectangular conductor,wherein: a melt flow rate of the insulating coating material at 372° C. is from 13 to 300 g/10 min;an average thickness of the film of the insulating coating material is from 10 to 1,000 μm;an unbiased standard deviation of the thickness of the film of the insulating coating material in the axial direction of the rectangular wire is less than 0.06 mm;the insulating coating material contains a fluorine-containing copolymer having a unit based on tetrafluoroethylene and a unit based on perfluoroalkyl vinyl ether; andthe rectangular wire is such that the film of the insulating coating material does not peel off from the rectangular conductor in a winding test conforming to “JIS3216-3:2011 5.1.2 Rectangular Wire”.