Porous Insulated Wire Coating for Uniform Thickness Control
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Solution Overview
Problem
Insulated wires with pore-forming enamel coatings are prone to defects in appearance and degradation in insulating properties due to thickness unevenness and void formation during the calcination process.
Innovation Solution
The insulated wire is manufactured by forming multiple insulating layers with a controlled thickness difference of 0.5 µm or less, using a method that involves applying a coating material containing a polyamide acid and a pore-forming agent, followed by specific temperature treatment to remove solvents and form pores, ensuring uniform thickness and reduced void formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pore forming agent is mixed with enamel coating material to form pores, then relative permittivity is lowered, but thickness unevenness and defects occur in the insulating coating
Solution Approach 1:
The insulating coating is divided into multiple insulating layers (at least two layers) with different pore forming agent contents. The inner layer has lower pore forming agent content (5-30 phr) while the outer layer has higher content (30-70 phr), allowing each layer to contribute differently to thickness uniformity and insulating properties, thereby resolving the contradiction between achieving low relative permittivity and maintaining thickness uniformity
Solution Approach 2:
Different regions of the insulating coating are given different properties by varying the pore forming agent content in different layers. The inner layer near the conductor has lower porosity for better adhesion and thickness control, while the outer layer has higher porosity for lower relative permittivity, creating local quality variations that resolve the overall contradiction
2Reliability
If high concentration of pore forming agent is used to reduce relative permittivity, then insulating property improves, but appearance defects and void formation increase
Solution Approach 1:
The insulating coating is segmented into multiple layers with different pore forming agent concentrations. The inner layer uses 5-30 phr to avoid excessive void formation near the conductor, while the outer layer uses 30-70 phr to achieve the desired low relative permittivity, thus preventing appearance defects while maintaining insulating properties
Solution Approach 2:
The concentration of pore forming agent is changed across different layers of the insulating coating. By gradually increasing the pore forming agent content from the inner layer to the outer layer, the patent optimizes both the insulating property (through lower relative permittivity) and appearance quality (by avoiding excessive porosity that causes defects)
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 suppresses defects in appearance and insulating property degradation by maintaining uniform thickness and reducing voids within the insulating layers, enhancing the wire's electrical insulation and appearance quality.
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
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AI summary
An insulated wire includes a conductor (20) having an elongated shape and an insulating coating (30). The insulating coating is provided around the conductor. The insulating coating is formed by laminating multiple insulating layers (33), each of which includes pores.