Polyimide Film Curing via Infrared Heating for Low Volatile Content
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Solution Overview
Problem
Polyimide films used in high-temperature applications, such as solar cells, often experience foaming and blistering due to residual volatile content, which is not adequately reduced by existing manufacturing methods.
Innovation Solution
The method involves using an infrared heater in conjunction with conventional heating means to gradually increase the ambient temperature to 450°C or higher during the curing process, ensuring efficient removal of solvents and volatile components, with the infrared heater positioned strategically to control the film's surface temperature and prevent excessive heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional heating means is used to remove volatile substances from polyimide film, then the curing process can be completed, but the volatile content remains at about 0.2 mass % which is insufficient for high-temperature applications
Solution Approach 1:
The patent applies parameter changes by introducing infrared radiation as a new heating parameter with different physical characteristics (electromagnetic radiation vs. conventional conduction/convection). This enables more effective volatile substance removal by directly heating the film to higher temperatures (450°C or higher) without excessive ambient temperature rise, achieving volatile content of 0.1 mass % or less and preventing foaming and blistering in high-temperature applications
2Quantity of substance
If the ambient temperature is raised too high during curing to remove volatiles, then volatile content decreases, but the film may decompose due to excessive heating
Solution Approach 1:
The patent applies local quality by creating a temperature gradient where the film surface is directly heated by infrared radiation to high temperatures (450°C or higher) for effective volatile removal, while the ambient temperature remains controlled and moderate. This localized heating approach allows thorough curing without exposing the entire system to temperatures that would cause film decomposition
Solution Approach 2:
The patent replaces conventional thermal conduction and convection heating mechanisms with infrared radiation heating. This substitution enables direct energy transfer to the film material, achieving high surface temperatures for volatile removal while maintaining controlled ambient conditions, thus preventing film decomposition
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 results in a polyimide film with a volatile content of 0.1 mass % or less, effectively preventing foaming and blistering during high-temperature processing, making it suitable for applications like solar cell substrates.
Implementation Method 1
uses heating by an infrared heater during heat treatment of the self-supporting film in which the ambient temperature thereof is brought to 450° C. or higher
Implementation Method 2
heat treating the self-supporting film to complete imidization thereof
Data Source
AI summary
A polyimide film which rarely undergoes the formation of bubbles, blisters or the like, even when heated to a high temperature; and a production method and a production apparatus for the polyimide film. The polyimide film production apparatus includes a support body, a cast furnace and a cure furnace, wherein the cure furnace is partitioned into multiple zones so that the temperature of a self-supporting film can be increased in a stepwise manner, and an infrared electric heater, which is disposed at a predetermined distance from the film, is arranged in a zone for heating the atmosphere of the self-supporting film to a temperature of 450° C. or higher on the upper surface side and/or the lower surface side of the self-supporting film. The polyimide production apparatus enables the production of a polyimide film which has a volatile content of 0.1 mass % or less after being heated at 450° C. for 20 minutes.