Norbornene Polymer Layers for Display Transparency and Thermal Stability
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Solution Overview
Problem
There is a need for transparent polymer layers in liquid crystal displays and organic light emitting diode displays that can meet evolving manufacturing requirements, including high transparency across the visible light spectrum, thermal stability, and resistance to solvents like N-Methyl-2-pyrrolidone, while maintaining hardness and minimal thickness change.
Innovation Solution
Norbornene-type polymers are developed, formed through the 2,3 enchainment of specific monomers with crosslinkable hydrocarbyl pendant groups and hydrocarbyl groups, which provide high transparency, thermal stability, and hardness, and are resistant to N-Methyl-2-pyrrolidone, using a combination of monomers and additives in layer-forming compositions with casting solvents and thermal acid generators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional transparent polymers are used in display manufacturing, then transparency is achieved, but thermal stability and solvent resistance are insufficient
Solution Approach 1:
The patent employs composite polymer structures combining norbornene backbone with crosslinkable pendant groups. This composite approach integrates the transparency of norbornene polymers with the thermal stability and solvent resistance of crosslinked networks, achieving both optical clarity and mechanical durability in display applications.
Solution Approach 2:
The patent modifies polymer parameters by introducing crosslinkable functional groups (epoxy, carboxylic acid, hydroxyl) that undergo chemical transformation during curing. This parameter change from linear to crosslinked structure enhances thermal stability and solvent resistance while preserving transparency through controlled crosslinking density.
2Strength
If polymer hardness is increased to meet scratch resistance requirements, then durability improves, but transparency may be compromised
Solution Approach 1:
The patent applies local quality by concentrating crosslinking functionality in pendant groups while maintaining a transparent norbornene backbone. The crosslinked regions provide localized hardness and scratch resistance, while the overall polymer matrix preserves optical transparency through its inherent norbornene structure.
Solution Approach 2:
The patent uses partial crosslinking rather than complete crosslinking to achieve optimal balance. By controlling the degree of crosslinking through stoichiometric ratios of crosslinkable groups, the patent obtains sufficient hardness for scratch resistance while avoiding excessive crosslinking that would compromise transparency.
3Temperature
If thermal stability is enhanced through material selection, then processing temperature tolerance improves, but transparency retention at high temperature may deteriorate
Solution Approach 1:
The patent employs sacrificial pendant groups that undergo controlled degradation or crosslinking at elevated temperatures. These groups act as thermal buffers, absorbing thermal stress and protecting the main norbornene chain from degradation, thereby preserving transparency even at high processing temperatures.
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 norbornene-type polymers achieve at least 95% initial transparency retention at 400 nm after exposure to 280°C for 30 minutes, exhibit minimal weight loss and thickness change, and demonstrate sufficient hardness and thermal stability, addressing the requirements for advanced display technologies.
Implementation Method 1
exposure in air to a temperature of 280° C. for 30 min; that exhibits no more than a 2% change in film thickness
Data Source
AI summary
Embodiments in accordance with the present invention provide polymers for forming layers/films useful in the manufacture of a variety of types of optoelectronic displays. Such embodiments also provide compositions of such polymers for forming such layers/films where the formed layers/films have high transparency over the visible light spectrum.