Transparent Resin Sealing Composition With Moisture Barrier
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Solution Overview
Problem
Existing sealing materials for moisture-sensitive devices like OLEDs and organic solar cells face challenges in maintaining transparency while providing effective water vapor penetration barrier properties, as calcium oxide, when used as a hygroscopic filler, typically reduces transparency and causes yellowing.
Innovation Solution
A resin composition comprising specific components: (A) a polymer with an acid anhydride or carboxy group and a molecular weight of 10,000 or more, (B) a polymer with a molecular weight of less than 10,000, (C) an isobutylene-containing polymer with a molecular weight of 10,000 or more, and (D) calcium oxide with a median size of 300 nm or less, which together form a resin layer that balances transparency and water vapor barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If calcium oxide is added as a hygroscopic filler to a sealing composition containing an olefin-based polymer, then water vapor penetration barrier property is improved, but transparency is lost
Solution Approach 1:
The patent changes the particle size parameter of calcium oxide from conventional larger sizes to fine particles with D50 of 10 μm or less (preferably 3 μm or less). This parameter change allows the calcium oxide to provide effective water vapor barrier properties while minimizing light scattering and maintaining transparency of the sealing layer
Solution Approach 2:
The patent creates a composite sealing composition by combining olefin-based polymer with fine calcium oxide particles. This composite material approach allows the calcium oxide to provide water vapor barrier functionality while the polymer matrix maintains transparency, achieving both requirements simultaneously
2Illumination intensity
If fine calcium oxide is used to suppress decrease in transparency, then transparency is improved, but yellowing is caused
Solution Approach 1:
The patent introduces silane-modified olefin-based polymer as an intermediary substance between the calcium oxide particles and the sealing composition matrix. This intermediary undergoes hydrolysis and condensation reactions to form a protective network that prevents yellowing while maintaining the transparency benefits of fine calcium oxide particles
Solution Approach 2:
The patent modifies the chemical structure parameter of the olefin-based polymer by introducing silane groups. This chemical modification enables the polymer to form crosslinked structures that prevent yellowing of the fine calcium oxide particles while maintaining transparency
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 resin composition effectively maintains transparency while providing a robust water vapor penetration barrier, suppressing yellowing and ensuring the integrity of the sealing layer.
Implementation Method 1
calcium oxide is known as a hygroscopic filler
Implementation Method 2
the property of suppressing the penetration of water vapor (sometimes referred to as 'water vapor penetration barrier property' in the present specification)
Data Source
AI summary
Provision of a resin composition capable of forming a resin composition layer that has simultaneously achieved both water vapor penetration barrier property and transparency. A resin composition containing the following component (A) to component (D): (A) a polymer having an acid anhydride group and/or a carboxy group, and a number average molecular weight of 10,000 or more, (B) a polymer having an acid anhydride group and/or a carboxy group, and a number average molecular weight of less than 10,000, (C) an isobutylene-containing polymer having a number average molecular weight of 10,000 or more, and (D) calcium oxide having a median size of 300 nm or less.