Poly(imide-amide) Copolymer for Flexible Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for a polymer material with improved optical and mechanical characteristics for flexible displays, particularly a transparent plastic film that can replace conventional window cover glass, requiring high hardness, high light transmittance, low haze, and low yellowness index, while existing poly(imide-amide) copolymers face challenges in simultaneously enhancing both mechanical and optical properties and are hindered by the production of halogenated by-products that require costly precipitation processes.
Innovation Solution
A poly(imide-amide) copolymer is developed through a reaction between a diamine with an amide structural unit-containing oligomer and a dianhydride, allowing for increased content of amide structural units without the need for a precipitation process, thereby improving mechanical properties and maintaining excellent optical properties, including a low yellowness index and high tensile modulus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the content of amide structural units is increased to improve mechanical properties, then tensile modulus is improved, but optical properties (yellowness index) deteriorate
Solution Approach 1:
The patent changes the chemical structure parameters of the diamine component by introducing specific aromatic groups (such as phenylene, pyridine-2,6-diyl, triazine-2,4-diyl groups) and controlling the amide structural unit content within 20-70 mole%. This parameter optimization allows achieving high tensile modulus (≥4 GPa) while maintaining low yellowness index (≤3), resolving the trade-off between mechanical and optical properties.
Solution Approach 2:
The patent creates a composite polyimide-polyamide copolymer structure by combining imide units from dianhydride and amide units from diamine in specific ratios. This composite structure at the molecular level enables simultaneous achievement of high mechanical strength and excellent optical clarity, as the imide units provide mechanical strength while the controlled amide units maintain optical transparency.
2Illumination intensity
If conventional polyimide is used to ensure good optical properties, then light transmittance is maintained, but mechanical strength (hardness) is insufficient
Solution Approach 1:
The patent develops a polyimide-polyamide copolymer that combines the optical advantages of polyimide with the mechanical advantages of polyamide. The copolymer structure integrates imide units (providing optical clarity and heat resistance) with amide units (providing mechanical strength and hardness), achieving both high light transmittance and high tensile modulus in a single material system.
Solution Approach 2:
The patent optimizes the compositional parameters by controlling the amide structural unit content within 20-70 mole% and selecting specific aromatic diamine structures. This parameter control enables the material to simultaneously achieve high mechanical strength (tensile modulus ≥4 GPa) and excellent optical properties (high light transmittance, low yellowness index), eliminating the need for separate hard coating layers.
3Productivity
If halogenated by-products are produced during synthesis, then reaction efficiency is improved, but additional precipitation processes are required increasing cost and complexity
Solution Approach 1:
The patent eliminates the harmful halogenated by-products from the synthesis process by replacing traditional halogen-based reagents with non-halogenated alternatives. This extraction of the harmful element (halogen) from the process removes the need for subsequent precipitation steps to remove HX salts, simplifying the process while maintaining high reaction efficiency and improving environmental compatibility.
Solution Approach 2:
The patent converts the potentially harmful halogenated by-products into a benefit-free process by using non-halogenated reagents. This eliminates the need for complex precipitation and purification steps, transforming a harmful process into a clean, efficient, and environmentally friendly synthesis route that maintains high productivity without additional process complexity.
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 new method enables the production of poly(imide-amide) copolymers with high mechanical strength and optical clarity, achieving a yellowness index of less than 3 and tensile modulus greater than 4 GPa, while reducing process time and cost by eliminating the precipitation step, thus addressing the trade-off between mechanical and optical properties in conventional methods.
Implementation Method 1
A polyimide-polyamide copolymer, which is a product of a reaction between a diamine including an amide structural unit-containing oligomer and a dianhydride
Data Source
AI summary
A poly(imide-amide) copolymer, which is a product of a reaction between a diamine including an amide structural unit-containing oligomer represented by Chemical Formula 1 and a dianhydride represented by Chemical Formula 3: wherein, groups and variables in Chemical Formulae 1 and 3 are the same as described in the specification.