Curable Silicone Rubber Composition for LED Packaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current silicone rubber compositions for LED enclosures face challenges in achieving both good adhesion to thermoplastic materials like PPA and metals while maintaining high transmittance and storage stability, often requiring metallic condensation catalysts that can deteriorate and limit material selection.
Innovation Solution
A curable silicone rubber composition incorporating organopolysiloxanes with alkenyl groups, hydrogen-containing siloxanes, a platinum group metal-based catalyst, and a tackifier component with alkenyl or hydrosilyl group-containing isocyanurate compounds and adhesion-imparting ingredients, which omits the need for metallic condensation catalysts and enhances adhesion and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silane coupling agents are added to improve adhesion, then adhesion force is improved, but product transmittance deteriorates due to turbidity during storage
Solution Approach 1:
The patent changes the chemical parameters of the coupling agent system by specifying exact molecular structures (gamma-methacryloxypropyltrimethoxysilane with 0.01-5 wt% and gamma-glycidoxypropyltrimethoxysilane with 0.01-5 wt%), controlling the ratio and concentration to achieve both adhesion and transparency. This precise parameter control prevents excessive reaction that would cause turbidity while maintaining sufficient adhesion force.
Solution Approach 2:
The patent uses a composite coupling agent system combining two different silane compounds with complementary properties. The gamma-methacryloxypropyltrimethoxysilane provides adhesion to PPA through methacryloxy groups, while gamma-glycidoxypropyltrimethoxysilane provides adhesion to metals through epoxy groups. This composite approach balances multiple adhesion requirements while controlling overall reactivity to maintain transparency.
2Strength
If metallic condensation catalysts are used to facilitate adhesion, then adhesion is improved, but catalyst deterioration occurs due to reaction with air, requiring special control processes
Solution Approach 1:
The patent extracts and eliminates the problematic metallic condensation catalyst from the formulation. Instead of using aluminum metal chelate catalysts that react with air and require special handling, the invention relies on the self-reactivity of the silane coupling agents and the platinum-catalyzed vulcanization system, removing the need for moisture-sensitive metallic catalysts and simplifying the process.
Solution Approach 2:
The patent replaces expensive and sensitive metallic catalysts with a more stable platinum-based catalytic system that is less reactive toward air. The coupling agents are designed to react controllably without requiring aggressive metallic catalysts, effectively using more stable, longer-lasting chemical systems that reduce process complexity.
3Reliability
If the refractive index difference is controlled within a narrow range to achieve transparency, then transmittance is improved, but material selection is limited
Solution Approach 1:
The patent changes the approach from controlling refractive index to controlling chemical composition and molecular structure. By selecting siloxane units with specific side chains (methyl, phenyl, vinyl groups) and controlling their ratios, the invention achieves both transparency and compatibility with diverse materials including PPA and various metals, expanding material selection beyond narrow refractive index matching.
4Strength
If various coupling agents are added to improve adhesion, then adhesion force is improved, but product transmittance deteriorates due to slow hydrolysis during storage causing turbidity
Solution Approach 1:
The patent precisely controls the hydrolysis rate by selecting silanes with methoxysilane groups that hydrolyze at a controlled pace. The specific molecular structures (gamma-methacryloxypropyltrimethoxysilane and gamma-glycidoxypropyltrimethoxysilane) are chosen to provide sufficient adhesion while maintaining slow, controlled hydrolysis that prevents rapid crosslinking and turbidity formation during storage.
Solution Approach 2:
The patent applies different functional groups at different locations in the molecule: the methoxysilane end provides controlled hydrolysis and adhesion to inorganic substrates, while the methacryloxy or epoxy groups provide adhesion to organic substrates like PPA. This local functional differentiation allows each part of the molecule to perform its specific function without compromising overall stability or 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 composition achieves improved adhesion to difficult-to-adhere substrates like PPA and metals with maintained high transmittance and storage stability, expanding material selection and avoiding catalyst-related issues.
Implementation Method 1
A curable silicone rubber composition incorporating organopolysiloxanes with alkenyl groups, hydrogen-containing siloxanes, a platinum group metal-based catalyst
Implementation Method 2
a tackifier component with alkenyl or hydrosilyl group-containing isocyanurate compounds and adhesion-imparting ingredients
Data Source
Figure 1
AI summary
The present invention relates to a curable silicone rubber composition for LED enclosure, the process for preparing the same and the use thereof. Particularly, the compositions comprise at least one tackifier component D, which comprises: a) a alkenyl or hydrosilyl group containing isocyanurate compound E, and b) an adhesion-imparting ingredient having at least two functional groups selected from alkenyl, epoxy, alkoxy and hydrosilyl groups, which is consisting of polysiloxane F and optional coupling agents G.