Thermoplastic Polyimide Insulated Wire Extrusion With Bubble Control
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Solution Overview
Problem
The production of insulated wires using thermoplastic polyimide (TPI) is inefficient and prone to bubble formation due to poor thermal stability, leading to reduced breakdown voltage and shortened service life.
Innovation Solution
A method involving a bonding layer formed by mixing polyamide-imide, polyimide, and organic solvent, followed by extrusion of thermoplastic polyimide under controlled negative pressure and specific temperature conditions to minimize bubble formation and enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the one-time extrusion process is used to improve production efficiency, then productivity is improved, but bubbles are easily formed in the insulating layer due to poor thermal stability of thermoplastic polyimide, reducing breakdown voltage
Solution Approach 1:
The patent applies preliminary action by pre-heating the core material before extrusion and using a bonding layer with specific composition (polyamide-imide, polyimide, and organic solvent) prepared in advance. This preliminary preparation ensures that when thermoplastic polyimide is extruded, the core material is already at the appropriate temperature and surface condition to minimize bubble formation, thus maintaining both high production efficiency and reliable breakdown voltage
Solution Approach 2:
The patent changes critical parameters including the composition of the bonding layer (specific ratios of polyamide-imide, polyimide, and organic solvent), the extrusion temperature, and the pre-heating temperature. By optimizing these parameters, the patent achieves successful one-time extrusion with minimal bubbles, resolving the contradiction between high productivity and reliable breakdown voltage
2Strength
If multiple times of coating and curing are performed to form the insulating layer, then adhesion is improved, but the operation becomes cumbersome and production efficiency decreases
Solution Approach 1:
The patent merges multiple coating and curing operations into a single extrusion process. By formulating a bonding layer with specific composition and applying it through one-time extrusion, the patent achieves the adhesion benefits of multiple layers without the operational complexity, thus improving production efficiency while maintaining strong adhesion
Solution Approach 2:
The patent changes the approach from multiple coating cycles to a single extrusion process by modifying the bonding layer composition (polyamide-imide, polyimide, organic solvent in specific ratios) and controlling extrusion parameters. This parameter change enables one-time formation of the insulating layer with adequate adhesion, eliminating the need for repeated operations
3Stability of the object's composition
If multiple times of baking are performed on the innermost layer, then curing is improved, but aging occurs and adhesion decreases
Solution Approach 1:
The patent applies preliminary action by pre-heating the core material to the appropriate temperature before extrusion and using a bonding layer formulation that cures effectively in a single extrusion cycle. This eliminates the need for multiple baking operations, preventing aging and adhesion decrease while ensuring complete curing, thus extending service life
Solution Approach 2:
The patent extracts the multiple baking operations from the process and replaces them with a single extrusion process using a specially formulated bonding layer. By removing the repetitive thermal cycling that causes aging, the patent maintains curing completeness while preserving adhesion and extending the service life of the insulated wire
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 method significantly reduces bubble size and content in the insulating layer, improving breakdown voltage and extending the service life of insulated wires and coils.
Implementation Method 1
vacuuming an extruder, and melting and extruding the thermoplastic polyimide at an outer side of the core material after preheating, so as to form a thermoplastic polyimide insulating layer, wherein the extruding process is carried out under a negative pressure condition; and a vacuum suction for applying the negative pressure is controlled to be larger than or equal to 0.3 MPa
Implementation Method 2
a preheating temperature is controlled to be 200° C.-320° C.
Implementation Method 3
melting and extruding the thermoplastic polyimide at an outer side of the core material after preheating, so as to form a thermoplastic polyimide insulating layer
Data Source
AI summary
An insulated wire, coil, and electronic or electrical device, and relates to the technical field of electrochemical components. An insulated wire, wherein, the insulated wire comprises the core material and the insulating layer coating the core material; the core material comprises a conductor and a bonding layer coated on the conductor; and the insulating layer is formed by the thermoplastic polyimide; the bonding layer comprises the following components: the polyamide-imide, the polyimide, and the organic solvent.