Polyimide Film Coating Adhesion via Polyamic Acid Promoter
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Solution Overview
Problem
Polyamide imide films lack adequate adhesion with hard coat formulations due to their solubility in polar, non-protic solvents, resulting in a poorly formed interface, which compromises the mechanical integrity and scratch resistance of polymer films used in display applications.
Innovation Solution
A coated film comprising a polyimide film, a curable resin coating composition with nanoparticles, and an adhesion-promoter based on polyamic acid composition is used, enhancing the interface between the polyimide film and the hard coat layer for improved adhesion and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a hard coat formulation containing non-protic solvents is used on polyimide films, then the coating process is simplified, but the adhesion between the hard coat layer and polyimide film deteriorates
Solution Approach 1:
The patent introduces a polyamic acid layer as an intermediary between the polyimide film and the hard coat layer. This intermediate layer contains carboxylic acid groups that form strong chemical bonds with both the polyimide substrate and the hard coat formulation, thereby resolving the adhesion problem while allowing the use of simplified non-protic solvent-based coatings.
Solution Approach 2:
The patent changes the chemical parameters of the interface by introducing a polyamic acid layer with specific functional groups (carboxylic acid) that have different bonding characteristics. This parameter change enables strong adhesion through chemical bonding rather than relying solely on physical adhesion, which fails with non-protic solvents.
2Adaptability or versatility
If polyimide films are used instead of glass substrates, then flexibility and thermal stability are improved, but hardness and scratch resistance deteriorate
Solution Approach 1:
The patent creates a composite structure consisting of the polyimide film substrate combined with a hard coat layer containing silicon oxide nanoparticles. This composite material combines the flexibility and thermal stability of polyimide with the hardness and scratch resistance of the ceramic-containing hard coat, resolving the contradiction between softness and durability.
3Reliability
If an adhesion promoter layer is added between polyimide film and hard coat, then adhesion is improved, but device complexity increases
Solution Approach 1:
The patent combines the adhesion promoter function with the interface region between the polyimide film and hard coat layer. The polyamic acid layer serves as both the bonding interface and part of the overall coating system, integrating multiple functions into a unified structure rather than adding a completely separate intermediate component.
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 solution significantly improves the adhesion and scratch resistance of polyimide films, ensuring better protection and performance in flexible display applications by forming a robust interface with the hard coat layer.
Implementation Method 1
The adhesion-promoter includes a polyamic acid composition and is on a surface of the polyimide film that is in contact with the curable resin coating composition
Implementation Method 2
The curable resin coating composition includes a curable oligomer
Data Source
AI summary
In a first aspect, a coated film includes a polyimide film, a curable resin coating composition and an adhesion-promoter. The curable resin coating composition includes a curable oligomer and first nanoparticles. The adhesion-promoter includes a polyamic acid composition and is on a surface of the polyimide film that is in contact with the curable resin coating composition. In a second aspect, an electronic device includes the coated film of first aspect.