Polyamide Base Film for Low Moisture Permeability
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Solution Overview
Problem
Existing polyimide-based films used in display devices face challenges with increased haze and decreased adhesive strength during hard-coating processes, leading to deteriorated optical properties, particularly in high-humidity environments.
Innovation Solution
A base film with a polyamide-based polymer and a moisture permeability of 300 g/m2·day or less, combined with a functional layer, is developed using a process involving the preparation of a polyamide-based polymer solution, casting, drying, and thermal treatment to create a colorless, transparent, and durable film suitable for cover windows in display devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyimide-based film is used as a base film in display devices, then heat resistance and chemical resistance are improved, but haze increases and adhesive strength decreases during hard-coating processes, leading to deteriorated optical properties
Solution Approach 1:
The patent uses a polyamide-based polymer as the base film material instead of conventional polyimide. This material substitution creates a composite structure that combines the heat resistance and chemical resistance required for reliability with improved optical properties and adhesive strength needed for manufacturing precision. The polyamide polymer serves as a composite material that integrates multiple desired properties into a single base film system.
Solution Approach 2:
The patent controls the moisture permeability parameter of the base film to be 300 g/m2·day or less. By adjusting this specific parameter of the polyamide-based polymer, the invention achieves both low haze and high adhesive strength during hard-coating processes while maintaining the thermal and chemical resistance properties. This parameter control resolves the contradiction between reliability and manufacturing precision.
2Reliability
If the base film is applied in high-humidity environments, then durability is required, but moisture permeability causes deterioration in mechanical and optical properties
Solution Approach 1:
The patent specifically controls the moisture permeability parameter to be 300 g/m2·day or less by selecting appropriate polyamide-based polymers and adjusting their molecular structure and density. This parameter change enables the base film to resist moisture penetration while maintaining durability in high-humidity environments, preventing deterioration of mechanical and optical properties.
Solution Approach 2:
The patent enhances the local quality of the base film by optimizing the polyamide polymer structure to provide low moisture permeability specifically at the molecular level, while maintaining overall film transparency and mechanical strength. This localized optimization of moisture resistance allows the film to perform reliably in humid environments without compromising other essential properties.
3Manufacturing precision
If transparency and mechanical properties are enhanced, then optical quality is improved, but moisture permeability may increase, affecting durability
Solution Approach 1:
The patent achieves a balanced optimization of multiple parameters by selecting polyamide-based polymers with specific molecular weights, chain structures, and crystallinity levels. These parameter adjustments simultaneously improve transparency and mechanical properties while maintaining moisture permeability at or below 300 g/m2·day, resolving the contradiction between optical quality and durability.
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 maintains excellent mechanical and optical properties, ensuring durability and preventing moisture penetration, thus enhancing the reliability and image quality of display devices even in high-humidity conditions.
Implementation Method 1
extruding and casting the polymer solution in the tank and then drying it to prepare a gel sheet
Implementation Method 2
thermally treating the gel sheet
Implementation Method 3
having a moisture permeability of 300 g/m2·day or less
Data Source
AI summary
Embodiments relate to a base film that is colorless, transparent, and excellent in mechanical properties and optical properties, particularly with low moisture permeability, a process for preparing the same, and a cover window and a display device comprising the same. The cover window comprises a base film comprising a polyamide-based polymer and having a moisture permeability of 300 g/m2·day or less; and a functional layer.