Thermosetting Composition for OLED Sealing
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Solution Overview
Problem
Conventional UV light curing epoxy resins used in organic electroluminescent devices are brittle and unsuitable for flexible substrates, prone to degradation and peeling due to stress changes during curing, and may not fully cure, leading to incomplete sealing and performance issues.
Innovation Solution
A thermosetting composition comprising 1-35 wt% oligomer derived from reacting liquid epoxy resin with aromatic primary amines, 5-10 wt% long chain resin, 50-80 wt% epoxy resin with multiple functional groups, and 5-15 wt% plasticizer, cured at lower temperatures and shorter times to enhance flexibility and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UV light curing epoxy resin is used for sealing, then the sealing process is fast and complete area coverage is achieved, but the resin is brittle and causes peeling due to stress changes
Solution Approach 1:
The patent changes the chemical composition parameters by using a thermosetting resin system with specific epoxy resins (containing at least two functional groups) combined with cyclic carboxylic acid anhydride curing agents and amine-based catalysts. This chemical parameter change transforms the resin from brittle UV-curing epoxy to a more flexible thermosetting system that can accommodate stress changes while maintaining complete area coverage sealing capability
Solution Approach 2:
The patent creates a composite sealing material system by combining multiple components: epoxy resins with specific functional groups, cyclic carboxylic acid anhydride curing agents, amine-based catalysts, and optional additives. This composite approach achieves both flexibility and adhesion while maintaining complete area coverage, resolving the contradiction between curing speed and mechanical properties
2Reliability
If high temperature curing is used to achieve complete cure, then the resin cures fully, but the curing temperature is too high (100-170°C) and degrades organic materials
Solution Approach 1:
The patent introduces amine-based catalysts (such as imidazole, triethylamine, or N,N-dimethylaminopyridine) as intermediaries to facilitate the curing reaction at lower temperatures. These catalysts lower the activation energy required for the epoxy-anhydride reaction, enabling complete curing at temperatures below 100°C and preventing degradation of organic electroluminescent materials
Solution Approach 2:
The patent changes the curing temperature parameter from high (100-170°C) to low (below 100°C, preferably 20-80°C) by modifying the chemical reaction system. This is achieved through the combination of cyclic carboxylic acid anhydride curing agents and amine-based catalysts, which enable complete curing at reduced temperatures, thus protecting organic materials from thermal degradation
3Productivity
If rapid stress changes occur during curing, then the curing process is fast, but the cathode and organic layer peel due to stress
Solution Approach 1:
The patent changes the resin's mechanical parameters by selecting epoxy resins with at least two functional groups and combining them with cyclic carboxylic acid anhydride curing agents. This creates a thermosetting network with appropriate flexibility and adhesion properties, allowing the resin to accommodate stress changes during curing without causing peeling of the cathode and organic layer
Solution Approach 2:
The patent applies the sealing resin with specific compositional characteristics (epoxy resins with multiple functional groups, cyclic carboxylic acid anhydride curing agents, and amine-based catalysts) to the sealing area. This localized application of optimized material properties ensures that the sealing layer has the precise adhesion and flexibility characteristics needed to prevent peeling while maintaining curing efficiency
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 thermosetting composition demonstrates excellent flexibility, adhesion to various substrates, inhibits dark spot formation, and exhibits good gas barrier properties, making it suitable for sealing organic electroluminescent devices without adverse effects.
Implementation Method 1
the oligomer is obtained by reacting a liquid epoxy resin with an aromatic primary amine having four active hydrogen atoms
Implementation Method 2
cured at lower temperatures and shorter times
Data Source
AI summary
The disclosure provides a thermosetting composition, including: (a) about 1-35 wt % of an oligomer, wherein the oligomer is obtained by reacting a liquid epoxy resin with an aromatic primary amine having four active hydrogen atoms, and the liquid epoxy resin and the primary amine have an equivalent mole ratio of 1:0.15-1:2.50; (b) about 5-10 wt % of a long chain resin; (c) about 50-80 wt % of an epoxy resin having at least two functional groups; and (d) about 5-15 wt % of a plasticizer.