Resin Composition for Organic EL Encapsulation
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Solution Overview
Problem
Existing sealing materials for organic electroluminescent elements have poor flexibility, water vapor barrier properties, and adhesive force, leading to the generation of dark spots due to moisture infiltration and substrate displacement, which affects the visibility and durability of flexible displays and lightings.
Innovation Solution
A resin composition for element encapsulation containing a diene polymer and a softening agent with a saturated hydrocarbon structure, specifically polybutene, along with a hydrogenated cyclic olefin compound, which provides excellent flexibility, water vapor barrier properties, and adhesive force, suppressing the generation of dark spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a sealing material containing a liquid softening agent in an amount equal to or more than the diene polymer is used, then flexibility is improved, but water vapor barrier properties and adhesive force are decreased
Solution Approach 1:
The patent applies parameter changes by precisely controlling the softening agent content within 5-30 mass% range and adjusting the diene polymer content to 70-95 mass%. This quantitative parameter optimization resolves the contradiction by finding the optimal balance point where flexibility is sufficient while water vapor barrier properties are maintained at acceptable levels.
Solution Approach 2:
The patent uses composite materials by combining diene polymer, softening agent, and inorganic filler in specific proportions. The inorganic filler (such as silica or alumina) compensates for the reduced water vapor barrier properties caused by the softening agent, creating a composite sealing material that achieves both flexibility and adequate barrier performance simultaneously.
2Ease of operation
If a sealing material containing a liquid softening agent in an amount equal to or more than the diene polymer is used, then flexibility is improved, but adhesive force is decreased
Solution Approach 1:
The patent applies parameter changes by optimizing the softening agent content to 5-30 mass% and diene polymer content to 70-95 mass%. This precise parameter control ensures that the sealing material maintains sufficient adhesive force (≥5 N/25mm in 180° peel test) while achieving the required flexibility for conformal contact.
Solution Approach 2:
The patent employs composite materials by incorporating inorganic fillers (such as silica, alumina, or titania) into the diene polymer-based sealing material. These fillers enhance the adhesive force and mechanical strength, compensating for the potential reduction in adhesion caused by the softening agent, thereby achieving both flexibility and strong bonding.
3Reliability
If glass sealing can is used to seal organic EL element, then moisture infiltration is prevented, but impact resistance and cost are poor
Solution Approach 1:
The patent replaces expensive and fragile glass sealing cans with a cost-effective polymer-based sealing material. The diene polymer composition provides sufficient durability and moisture barrier performance without the fragility of glass, making it suitable for flexible and wearable applications where cost and impact resistance are critical.
Solution Approach 2:
The patent employs flexible shells and thin films by using a polymer-based sealing material that can conform to the organic EL element and provide effective moisture barrier protection. This flexible sealing approach replaces rigid glass cans, enabling application to flexible substrates and improving impact resistance while maintaining moisture prevention capabilities.
4Ease of operation
If sealing material with low adhesive force is used, then flexibility is maintained, but substrate displacement and peeling occur under impact
Solution Approach 1:
The patent applies parameter changes by optimizing the diene polymer content to 70-95 mass% and softening agent content to 5-30 mass%. This parameter optimization ensures that the sealing material achieves both flexibility and sufficient adhesive force (≥5 N/25mm), preventing substrate displacement and peeling under impact while maintaining conformal contact capability.
Solution Approach 2:
The patent uses composite materials by combining diene polymer, softening agent, and inorganic filler. The inorganic filler enhances the mechanical strength and adhesive properties of the sealing material, allowing it to maintain strong substrate bonding under impact while retaining the flexibility needed for conformal contact with the organic EL element.
Data Source
AI summary
Provided are a resin composition for element encapsulation for organic electronic devices which is transparent, has excellent flexibility, water vapor barrier properties, and adhesive force, and can suppress the generation of dark spots, a resin sheet for element encapsulation for organic electronic devices, an organic electroluminescent element, and an image display device. This adhesive resin composition for element encapsulation for organic electronic devices is used to seal an element for organic electronic devices, and is characterized by containing a diene polymer and a softening agent, in which the content of the softening agent is from 5% by mass to 30% by mass of the total mass.