Polyurethane-Polyamide Imide Insulation for Cord-Shaped Heater Terminals
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Solution Overview
Problem
Existing cord-shaped heaters face issues with conductive wire disconnection leading to abnormal heating due to increased current density at thin areas, and insulating films made of materials like silicone resin or polyimide resin are difficult to process, affecting productivity and connectivity.
Innovation Solution
A cord-shaped heater design with an insulating film comprising an inner layer of polyurethane resin and an outer layer of polyamide imide resin, where the inner layer thermally decomposes at a lower temperature than the outer layer, allowing for easy removal and exposing the conductive wires for connection, enhancing workability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating film is made of silicone resin or polyimide resin to achieve excellent heat resistance and incombustibility, then the heat resistance and incombustibility are improved, but the ease of manufacture deteriorates due to difficulty in processing the terminal
Solution Approach 1:
The insulating film is divided into two layers: an inner layer made of polyurethane resin that is easily removed by polishing, and an outer layer made of silicone resin or polyimide resin that provides heat resistance and incombustibility. This segmentation allows each layer to fulfill its specific function while the inner layer enables easy terminal processing.
Solution Approach 2:
The insulating film uses a composite structure combining polyurethane resin (inner layer) with silicone resin or polyimide resin (outer layer). This composite material approach allows the inner layer to be easily removed during terminal processing while the outer layer maintains excellent heat resistance and incombustibility properties.
2Reliability
If the insulating film is made of silicone resin or polyimide resin to achieve excellent heat resistance and incombustibility, then the heat resistance and incombustibility are improved, but the productivity deteriorates due to requirement of separate polishing process
Solution Approach 1:
The insulating film is segmented into an inner polyurethane resin layer that can be easily removed by polishing and an outer silicone resin or polyimide resin layer that provides heat resistance and incombustibility. This segmentation enables the inner layer to be removed during terminal processing without requiring a separate polishing step, thereby improving productivity.
Solution Approach 2:
The composite insulating film structure with polyurethane resin inner layer and silicone resin or polyimide resin outer layer allows the inner layer to be removed during terminal processing, eliminating the need for separate polishing operations and improving manufacturing efficiency.
3Reliability
If the conductive wires are connected to lead wire by soldering, then the electrical connection is achieved, but the insulating film cannot be removed since it does not melt at solder-melting temperature
Solution Approach 1:
The insulating film is segmented into an inner polyurethane resin layer that can be removed by polishing during terminal processing and an outer silicone resin or polyimide resin layer that remains intact. This segmentation allows the inner layer to be removed without affecting the outer protective layer, enabling easy terminal processing while maintaining electrical connection integrity.
Solution Approach 2:
The composite insulating film structure allows the inner polyurethane resin layer to be removed during terminal processing while the outer silicone resin or polyimide resin layer maintains its protective function, enabling easy terminal processing without compromising electrical connection reliability.
4Reliability
If the conductive wires are connected to lead wire by crimping, then the electrical connection is achieved, but the conductive wires and lead wire are not electrically connected since the insulating film is not destroyed by crimping pressure
Solution Approach 1:
The insulating film is segmented into an inner polyurethane resin layer that can be removed by polishing during terminal processing and an outer silicone resin or polyimide resin layer that provides protection. This segmentation enables the inner layer to be removed during crimping operations, allowing electrical connection while maintaining the outer protective layer.
Solution Approach 2:
The composite insulating film structure with polyurethane resin inner layer and silicone resin or polyimide resin outer layer allows the inner layer to be removed during terminal processing, enabling electrical connection between conductive wires and lead wire while maintaining the outer protective layer's integrity.
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 design ensures easy removal of the insulating film without polishing, improving productivity and ensuring reliable electrical connections by exposing conductive wires, thus preventing abnormal heating and enhancing overall heater performance.
Implementation Method 1
the thermal decomposition temperature of a first material constituting the inner layer is lower than the melting temperature of a second material constituting the outer layer and lower than the thermal decomposition temperature of the second material
Data Source
AI summary
Provided with a cord-shaped heater and a sheet-shaped heater using the cord-shaped heater enabling to process the terminal easily. A cord-shaped heater 10 including one or a plurality of conductive wires 5a covered with an insulating film 5b, wherein the insulating film 5b at least includes an inner layer formed on the conductive wires 5a and an outer layer formed outside the inner layer, the thermal decomposition temperature of a material constituting the inner layer is lower than the melting temperature of a material constituting the outer layer and lower than the thermal decomposition temperature of the second material, the thickness of the inner layer is 2 μm or more, the thickness of the inner layer is 5 μm or less or less than two-third of the entire thickness of the insulating film, the thickness of the outer layer is 1 μm or more, and the thickness of the outer layer is 5 μm or less or less than three-fourth of the entire thickness of the insulating film. The material constituting the inner layer is a polyurethane resin, and the material constituting the outer layer is a polyamide imide resin. A sheet-shaped heater, wherein the cord-shaped heater is arranged on a substrate.