Aromatic Polyamide Film for Display Substrates
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Solution Overview
Problem
The manufacturing of display, optical, and sensor elements using glass substrates faces issues such as weight, fragility, and warpage deformation during heat treatment, which affects the quality and yield of these elements, particularly due to high coefficients of thermal expansion in polyamide films.
Innovation Solution
A polyamide solution comprising an aromatic polyamide with at least two types of constitutional units, which exhibits a coefficient of thermal expansion change rate of 1.3 or less after heat treatment, is applied to a glass plate to form a film with improved thermal stability and reduced warpage deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If glass substrates are used for display elements, then transparency is improved, but weight increases and breakability worsens
Solution Approach 1:
The patent changes the material parameters by developing a polyamide resin composition with specific molecular weight (Mw/Mn ratio of 1.5 or less) and controlled gel fraction (5-50%), which enables the resin to achieve glass-like transparency while maintaining flexibility and reduced weight. This parameter optimization allows the polyamide film to serve as a lightweight alternative to glass substrates.
2Temperature
If polyimide is used for heat resistance, then heat resistance is improved, but transparency worsens due to brown coloration
Solution Approach 1:
The patent creates a composite polyamide resin system combining aromatic polyamides (providing heat resistance with Tg of 200-400°C) with cyclic carbonate crosslinking agents. This composite structure achieves both high heat resistance and optical transparency, overcoming the brown coloration issue of conventional polyimides while maintaining the required thermal stability for display element manufacturing.
3Reliability
If high heat treatment temperature is applied, then curing is improved, but warpage deformation increases due to high CTE of polyamide film
Solution Approach 1:
The patent addresses thermal expansion mismatch by formulating a polyamide resin composition with specific structural characteristics (low Mw/Mn ratio, controlled gel fraction) that reduce the coefficient of thermal expansion (CTE). This formulation allows the resin to undergo effective curing at high temperatures while minimizing warpage deformation caused by thermal expansion differences between the polyamide film and glass substrate.
4Strength
If aromatic polyamide with trifluoro group is used, then stiffness and heat resistance are improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the molecular parameters of aromatic polyamides by controlling the Mw/Mn ratio to 1.5 or less and adjusting the gel fraction to 5-50%, which simplifies the manufacturing process. This parameter control enables the use of aromatic polyamides with trifluoro groups (providing high stiffness and heat resistance) while avoiding complex processing conditions, allowing standard casting and curing methods to achieve the desired performance.
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 effectively suppresses warpage deformation and enhances the thermal stability of laminated composite materials, improving the manufacturing process and quality of display, optical, and sensor elements by maintaining a low coefficient of thermal expansion and high light transmittance.
Implementation Method 1
a change rate of coefficient of thermal expansion (CTE) of a cast film produced by casting the polyamide solution on a glass plate and CTE of the same cast film after being subjected to a heat treatment at temperature of 200° C. to 450° C.
Implementation Method 2
a polyamide solution comprising an aromatic polyamide and a solvent... casting the polyamide solution on a glass plate and CTE of the same cast film after being subjected to a heat treatment
Data Source
AI summary
The present disclosure, in one aspect, relates to a polyamide solution including an aromatic polyamide and a solvent, wherein the aromatic polyamide includes at least two types of constitutional units, and a change rate of coefficient of thermal expansion (CTE) of a cast film produced by casting the polyamide solution on a glass plate and CTE of the same cast film after being subjected to a heat treatment at temperature of 200° C. to 450° C. (=CTE after heat treatment/CTE before heat treatment) is 1.3 or less.