Polysiloxane Composition for LED Encapsulant Gas-Barrier
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Solution Overview
Problem
Polysiloxane compositions face challenges in achieving high heat and light resistance while maintaining excellent gas-barrier properties, particularly in applications like white LEDs, and existing solutions do not adequately address the issue of low gas-barrier properties and productivity in encapsulant materials.
Innovation Solution
A polysiloxane composition is developed, featuring a modified polyhedral polysiloxane obtained by modifying an alkenyl group-containing polyhedral polysiloxane with a hydrosilyl group-containing compound, combined with an organopolysiloxane containing alkenyl groups, which after curing exhibits low water vapor permeability and includes aryl group-containing organopolysiloxanes or cyclic olefin compounds for enhanced gas-barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a polysiloxane composition containing oxetanyl and epoxy groups is used to achieve high refractive index and high light extraction efficiency, then light extraction efficiency is improved, but heat resistance and light resistance become low
Solution Approach 1:
The patent uses a composite material system comprising a polyhedral polysiloxane backbone combined with specific side chain structures containing fluorinated groups and cyclic carbonate groups. This composite structure achieves both high light extraction efficiency through optimized refractive index and high heat/light resistance through the stable polyhedral skeleton, resolving the contradiction between light extraction efficiency and heat resistance
Solution Approach 2:
The patent changes the chemical structure parameters by introducing fluorinated side chains and cyclic carbonate groups onto the polyhedral polysiloxane backbone. These parameter changes optimize the refractive index for light extraction while the fluorinated groups enhance thermal stability, simultaneously improving both light extraction efficiency and heat resistance
2Ease of manufacture
If polysiloxane composition with low gas-barrier properties is used as encapsulant, then ease of manufacture is improved, but the reflector turns black due to sulfide
Solution Approach 1:
The patent applies local quality by incorporating sulfur-resistant functional groups (cyclic carbonate and fluorinated groups) at specific locations on the polysiloxane chains. This localized functionalization provides sulfur barrier protection exactly where needed to prevent reflector blackening, while maintaining the overall ease of manufacture of the polysiloxane composition
3Reliability
If acrylic resin coating is applied to metal members before encapsulating with silicone resin to improve gas-barrier properties, then gas-barrier properties are improved, but productivity decreases due to additional processes
Solution Approach 1:
The patent merges the gas-barrier function and sulfur resistance function into the encapsulant material itself by incorporating cyclic carbonate groups and fluorinated side chains. This consolidation eliminates the need for separate acrylic resin coating processes, achieving excellent gas-barrier properties and sulfur resistance while maintaining high productivity through a single encapsulation process
4Temperature
If modified polyhedral polysiloxane is used to improve moldability, transparency, heat and light resistance, and adhesion, then these properties are improved, but gas-barrier properties still need further improvement
Solution Approach 1:
The patent changes the chemical parameters by introducing fluorinated side chains and cyclic carbonate groups onto the polyhedral polysiloxane backbone. These parameter changes simultaneously enhance gas-barrier properties through the fluorinated groups' low permeability characteristics while maintaining the heat and light resistance provided by the polyhedral skeleton
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 composition demonstrates high heat and light resistance with excellent gas-barrier properties, reducing water vapor and gas permeation, thus enhancing the durability of LED components and improving the encapsulant's performance in optical devices.
Implementation Method 1
a modified polyhedral polysiloxane which is obtained by modifying (a) an alkenyl group-containing polyhedral polysiloxane compound with (b) a hydrosilyl group-containing compound
Data Source
AI summary
The present invention aims to provide a polysiloxane composition which exhibits high heat and light resistance, and excellent gas-barrier properties. The polysiloxane composition of the present invention includes: (A) a modified polyhedral polysiloxane which is obtained by modifying (a) an alkenyl group-containing polyhedral polysiloxane compound with (b) a hydrosilyl group-containing compound; and (B) an organopolysiloxane containing at least two alkenyl groups in a molecule, wherein the polysiloxane composition after curing has a water vapor permeability of not more than 30 g/m2/24 h, and the polysiloxane composition includes (B1) an aryl group-containing organopolysiloxane as the organopolysiloxane (B), and/or (C) a component which is (C1) an organosilicon compound that contains one alkenyl or hydrosilyl group in a molecule, or (C2) a cyclic olefin compound that contains one carbon-carbon double bond in a molecule.