Humidity-Stable Polyimide Film for Precise Metal Foil Lamination
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Solution Overview
Problem
Polyimide films used in flexible metal-clad laminates experience significant deterioration in dimensional stability when exposed to humidity during manufacturing, transportation, and storage, which affects the quality of the final product.
Innovation Solution
A polyimide film with a temperature-rise coefficient of thermal expansion (50° C. to 200° C.) in the transverse direction of −1.5 ppm/° C. or higher and 6 ppm/° C. or lower, manufactured by reacting specific acid dianhydride and diamine components, followed by cast coating and imidization, is provided.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyimide films are used in flexible metal-clad laminates during manufacturing, transportation, and storage, then the films are exposed to varying humidity conditions, but the dimensional stability of the films deteriorates when exposed to humidity
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyimide film by incorporating specific additives and controlling the ratio of polyimide resin to other components. This changes the molecular structure and intermolecular forces within the film, enabling it to resist humidity-induced dimensional changes while maintaining flexibility and processability
Solution Approach 2:
The patent creates a composite polyimide film system by combining polyimide resin with specific additives and other materials in controlled ratios. This composite structure provides enhanced dimensional stability against humidity while retaining the base properties of polyimide, effectively resolving the contradiction between reliability under humidity exposure and the inherent sensitivity to moisture
2Weight of moving object
If the polyimide film is made thinner to reduce weight and size of electronic products, then the film becomes more flexible, but the dimensional stability deteriorates under humidity conditions
Solution Approach 1:
The patent changes the chemical and physical parameters of thin polyimide films through additive incorporation and compositional control. This enables thin films to achieve dimensional stability comparable to or better than thicker films by modifying the material's response to humidity at the molecular level, rather than relying solely on increased thickness
3Ease of manufacture
If the polyimide film undergoes high-temperature application processes during manufacturing, then the metal foil lamination is achieved, but the dimensional stability of the film deteriorates after humidity exposure
Solution Approach 1:
The patent applies preliminary action by pre-treating the polyimide film with specific additives and compositional modifications before the high-temperature lamination process. This preliminary preparation ensures that the film maintains dimensional stability during subsequent humidity exposure, even after undergoing high-temperature manufacturing processes
Solution Approach 2:
The patent modifies the thermal and moisture resistance parameters of the polyimide film through chemical composition adjustments. This enables the film to withstand both high-temperature lamination processes and subsequent humidity exposure without dimensional degradation, resolving the contradiction between manufacturability and post-processing reliability
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 polyimide film maintains excellent dimensional stability even after exposure to humidity, ensuring high-quality metal foil lamination and improved performance in flexible metal-clad laminates.
Implementation Method 1
heating the resulting product to manufacture a self-supporting film of the polyamic acid solution; and imidizing and stretching the self-supporting film to manufacture a polyimide film
Implementation Method 2
a temperature-rise coefficient of thermal expansion (50° C. to 200° C.) in a transverse direction (TD) of −1.5 ppm/° C. or higher and 6 ppm/° C. or lower in dimensional change measurement by a thermomechanical analyzer (TMA) involving a temperature rise process from 25° C. to 400° C.
Data Source
AI summary
The present invention provides a polyimide film and a manufacturing method therefor, wherein in the dimension change measurement by a thermomechanical analyzer (TMA) that performs a temperature rise procedure from 25° C. to 400° C. after storage for 48 hours at a humidity of 50% RH, the temperature-rise thermal expansion coefficient (50 to 200° C.) in the TD direction is −1.5 ppm/° C. to 6 ppm/° C., the temperature-rise thermal expansion coefficient (50 to 200° C.) being the slope of a straight line connecting a dimensional measurement value in the TD direction of the polyimide film as measured at 200° C. in the first run during the temperature rise procedure and a dimensional measurement value in the TD direction of the polyimide film as measured at 50° C. in the first run during the temperature rise procedure, and the dimensional measurement values in the TD direction correspond to dimensional change values calculated by converting, into 1 m, the length of a sample of the polyimide film used in the measurement by the thermomechanical analyzer.