Porous Insulated Wire Coating With Uniform Layer Thickness
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Solution Overview
Problem
Insulated wires with pores in the enamel coating are prone to defects in appearance and decreased insulating properties due to thickness unevenness caused by the thermal decomposition and evaporation of pore-forming agents during calcination.
Innovation Solution
The insulated wire is manufactured by laminating multiple insulating layers with controlled thickness differences of 0.5 μm or less, using a method that adjusts the thickness based on the sum of resin and pore-forming agent volumes, and includes a process to remove solvents and form pores through imidization and thermal decomposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pores are formed inside the enamel coating by using a pore forming agent, then the relative permittivity of the enamel coating is lowered, but the insulating wire becomes prone to defects in appearance and decreased insulating property due to thickness unevenness
Solution Approach 1:
The patent applies preliminary thickness adjustment by passing the coated conductor through a die with a through-hole before calcination. This preliminary action controls the coating material thickness to within 0.5 μm or less, compensating for the thickness unevenness that will occur later when the pore forming agent decomposes and creates pores. The die acts as a pre-adjustment mechanism that ensures uniform final thickness despite the porosity formation process.
Solution Approach 2:
The patent changes the thickness parameter of the coating material applied before calcination to account for the volume reduction that occurs during pore formation. By controlling the initial coating thickness and adjusting it through the die, the final insulating layer achieves uniform thickness (0.5 μm or less variation) even after the pore forming agent decomposes and creates voids, thereby maintaining both insulating property and thickness uniformity.
2Reliability
If a pore forming agent with high boiling point is used to create pores, then the enamel coating achieves lower relative permittivity, but the process becomes more complex and requires precise thickness control
Solution Approach 1:
The die with a through-hole serves as an intermediary device that simplifies the manufacturing process. Instead of requiring complex real-time thickness monitoring and adjustment during calcination, the die provides a passive, mechanical means of controlling coating thickness before the pore forming agent decomposes. This intermediary structure enables precise thickness control without adding complex control systems to the calcination process itself.
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
This approach effectively reduces defects and maintains insulating properties by minimizing thickness unevenness and ensuring consistent layer thickness, enhancing the wire's appearance and performance.
Implementation Method 1
heating the coating material having the specific thickness to a specific temperature, to thereby remove the solvent in the coating material
Implementation Method 2
thermally decomposing or vaporizing the pore forming agent contained in the coating material, to thereby form an insulating layer
Implementation Method 3
imidizing the polyamide acid contained in the coating material in a state where phase separation occurs between the pore forming agent and the polyamide acid
Data Source
AI summary
An insulated wire includes a conductor having an elongated shape and an insulating coating. The insulating coating is provided around the conductor. The insulating coating is formed by laminating multiple insulating layers, each of which includes pores.