Polyimide Synthesis Viscosity Control for Flexible Displays
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Solution Overview
Problem
Polyimide resins used in flexible displays require high transparency and low birefringence to replace glass substrates effectively, but existing methods struggle to achieve optimal mechanical and thermal properties while maintaining these optical qualities.
Innovation Solution
A method involving the controlled reaction of tetracarboxylic compounds and diamines in a solvent, where the viscosity is monitored and adjusted by incremental addition of diamine, allowing for precise control of molecular weight and optical transparency, resulting in polyimide materials with enhanced tensile strength, glass transition temperature, and optical clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If polyimide resin is used to replace glass substrate in flexible displays, then flexibility and lightweight properties are improved, but achieving high transparency and low birefringence becomes difficult
Solution Approach 1:
The patent applies parameter changes by systematically adjusting the molar ratio of diamine to tetracarboxylic compound (using 99.5 mol% or less of diamine), reaction temperature (60-200°C), and reaction time to control the molecular weight and structure of polyimide. This creates a new parameter space for polyimide synthesis that achieves both flexibility and optical quality, resolving the contradiction between material flexibility and optical precision.
2Strength
If conventional polyimide synthesis methods are used, then manufacturing process is simple, but mechanical strength and thermal stability cannot be optimized simultaneously
Solution Approach 1:
The patent implements feedback control by monitoring reaction viscosity during polyimide synthesis and using this information to adjust the addition rate of diamine and reaction conditions. This real-time feedback mechanism allows optimization of mechanical strength and thermal stability through controlled molecular weight development, while maintaining a manageable process through systematic viscosity-based decision making.
Solution Approach 2:
The patent applies preliminary action by pre-determining the maximum viscosity threshold and planned diamine addition schedule based on target molecular weight and desired polyimide properties. This pre-planned approach allows systematic optimization of mechanical strength before final product formation, reducing the need for complex post-processing adjustments.
3Strength
If high molecular weight polyimide is produced to improve mechanical properties, then tensile strength increases, but viscosity control becomes difficult and optical transparency may deteriorate
Solution Approach 1:
The patent applies partial action by intentionally using 99.5 mol% or less of diamine relative to tetracarboxylic compound, creating a controlled excess of tetracarboxylic compound. This partial completion of the reaction allows precise control of molecular weight and viscosity while still achieving high tensile strength through optimized polymer chain development, preventing both excessive viscosity and optical deterioration.
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 method produces polyimide materials with improved mechanical properties and high optical transparency, suitable for flexible display applications, ensuring clear images and durability.
Implementation Method 1
a method for preparing a polyimide includes placing a tetracarboxylic compound and a solvent in a reaction vessel. The method can include adding a first amount of a diamine, wherein the first amount is not more than 99.5 mol % of the tetracarboxylic compound to the reaction vessel to form a mixture
Implementation Method 2
The method can further include agitating the mixture
Implementation Method 3
The method can further include determining a viscosity of the mixture
Data Source
AI summary
The present disclosure describes methods of polyimide synthesis and polyimides made therefore. The method includes placing a tetracarboxylic compound and a solvent in a reaction vessel and adding a first amount of a diamine. The first amount of the diamine is not more than 99.5 mol % of the tetracarboxylic compound inside the reaction vessel. The method can include agitating the mixture and determining a viscosity of the mixture. The method can further include adding a second amount of the diamine. The last steps can be repeated until the viscosity increases to a target value. The target viscosity can be correlated to a peak weight-averaged molecular weight of the polyimide.