Fluorinated Elastomer PSA for Encapsulating Optoelectronics
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Solution Overview
Problem
Existing encapsulation methods for (opto)electronic arrangements, particularly organic electronics, face challenges in providing a durable, flexible, and transparent barrier against water vapor and oxygen, which can lead to degradation of performance in devices like OLEDs and solar cells, due to limitations in adhesion, permeability, and handling issues with current adhesives.
Innovation Solution
A pressure-sensitive adhesive (PSA) comprising at least 70% by weight of a mixture of fluorine-containing thermoplastic elastomer and fluorine-containing liquid elastomer, with specific ratios and combinations, offering excellent adhesion, flexibility, and barrier properties against water vapor and oxygen, while being easy to apply and process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass or metal substrates are used for encapsulation, then permeation barrier performance is improved, but mechanical flexibility and transparency are worsened
Solution Approach 1:
The patent employs flexible planar substrates such as polymer foils (PET, PEN, PI, PVDF) instead of rigid glass or metal substrates. These thin film substrates provide the necessary mechanical flexibility and transparency while serving as the base for encapsulation, directly resolving the contradiction between barrier performance and flexibility.
Solution Approach 2:
The patent creates a composite encapsulation structure combining multiple layers including flexible substrates, adhesive layers, and barrier coatings. This composite approach allows each layer to contribute its specific properties - flexibility from the substrate, adhesion from the adhesive, and permeation barrier from the coating - thereby achieving both flexibility and barrier performance simultaneously.
2Ease of operation
If conventional adhesives are used for sealing, then ease of application is improved, but adhesion strength and chemical resistance are worsened
Solution Approach 1:
The patent modifies adhesive properties by selecting specific polymer types (silicone, polyurethane, acrylic) and adjusting their molecular weight, crosslinking density, and composition ratios. These parameter changes enable the adhesive to simultaneously achieve easy application (through appropriate viscosity and tack) and high adhesion strength with chemical resistance (through optimized molecular structure and crosslinking).
Solution Approach 2:
The patent develops composite adhesive formulations combining multiple polymer types and additives. For example, it uses mixtures of silicone and polyurethane, or acrylic with functional additives, to achieve a balance between ease of application and enhanced adhesion strength and chemical resistance to electrolytes and permeates.
3Strength
If thick adhesive layers are used for encapsulation, then adhesion strength is improved, but permeation barrier performance and flexibility are worsened
Solution Approach 1:
The patent employs thin film adhesive layers (typically 1-10 micrometers) instead of thick adhesive layers. These thin films maintain sufficient adhesion strength while providing better flexibility and improved permeation barrier performance by reducing the diffusion path length for permeates.
Solution Approach 2:
The patent creates a multi-layer composite structure where a thin adhesive layer is combined with a separate barrier coating layer. This allows the adhesive layer to be thin (maintaining flexibility and barrier performance) while the barrier coating provides enhanced permeation protection, and the overall structure maintains strong adhesion through the composite design.
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 PSA provides a robust barrier with low water vapor and oxygen transmission rates, high adhesion strength, and flexibility, ensuring long-term protection and performance of (opto)electronic devices, suitable for encapsulating sensitive components like dye solar cells and OLEDs without the limitations of traditional adhesives.
Implementation Method 1
A pressure-sensitive adhesive (PSA) comprising at least 70% by weight of a mixture of fluorine-containing thermoplastic elastomer and fluorine-containing liquid elastomer, with specific ratios and combinations, offering excellent adhesion, flexibility, and barrier properties against water vapor and oxygen
Data Source
Figure 1~2
Figure 3~4
AI summary
A pressure-sensitive adhesive material particularly for encasing an electronic arrangement to prevent permeate, which material comprises at least 70 percent by weight, preferably 90 percent by weight (relative in each case to the total composition of the pressure-sensitive adhesive material) of a mixture of at least one fluorine-containing thermoplastic elastomer and at least one fluorine-containing liquid elastomer, wherein the mass ratio of the fluorine-containing liquid elastomer to the fluorine-containing thermoplastic elastomer is between 5:95 to 55:45, preferably between 15:75 and 50:50 and particularly preferably between 25:75 and 40:60.