Addition Curable Silicone Resin for LED Thermal Shock Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LED sealing materials, such as epoxy resins and silicone resins, face issues with thermal shock resistance and cracking due to temperature cycling, leading to reduced light emission efficiency and adhesion problems.
Innovation Solution
An addition curable silicone resin composition comprising an organopolysiloxane with a straight-chain segment for flexibility and a resin-like segment for rigidity, combined with an organohydrogenpolysiloxane and an addition reaction catalyst, providing enhanced thermal shock resistance and adhesion to metals and plastics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If epoxy resin is used as LED sealing material, then adhesion strength is improved, but thermal shock resistance deteriorates due to high elastic modulus causing bonding wire stress and cracks
Solution Approach 1:
The invention uses a composite silicone resin system combining polyorganosiloxane with polydiorganosiloxane containing alkenyl groups. This composite approach creates a material with optimized mechanical properties - the silicone base provides flexibility and thermal shock resistance while the crosslinking agents enhance adhesion strength, resolving the contradiction between strong bonding and thermal durability.
Solution Approach 2:
The invention modifies the elastic modulus parameter by introducing a flexible backbone structure through specific siloxane units. The use of dimethylsiloxane and other flexible units in the polymer chain reduces the elastic modulus compared to epoxy resin, allowing the material to accommodate thermal expansion differences without generating excessive stress on bonding wires during temperature cycling.
2Reliability
If silicone rubber is used as buffer material, then thermal shock resistance is improved, but adhesion deteriorates due to poor bonding between silicone rubber and epoxy resin causing interface peeling
Solution Approach 1:
The invention introduces local quality variations by incorporating specific functional groups at different positions in the molecular structure. The silane crosslinking agents provide localized regions of enhanced bonding capability at interfaces, while the bulk polymer maintains flexibility. This local differentiation enables simultaneous achievement of thermal shock resistance and strong adhesion without interface peeling.
3Temperature
If conventional silicone resin is used, then heat resistance and color fastness are improved, but mechanical strength deteriorates due to low flexural strength causing cracks under thermal shock
Solution Approach 1:
The invention performs preliminary structural reinforcement by incorporating crosslinking agents during the polymerization process. The polydiorganosiloxane with alkenyl groups forms a preliminary crosslinked network structure that pre-strengthens the material before it undergoes thermal shock. This preliminary action ensures the resin maintains both heat resistance and sufficient flexural strength to resist cracking under thermal stress.
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 yields a cured product with excellent thermal shock resistance, transparency, and adhesion, suitable for LED elements and optical devices, reducing cracking and improving light emission efficiency.
Implementation Method 1
an addition curable silicone resin composition comprising: an organopolysiloxane (A) comprising: a straight-chain segment represented by a general formula (1)...; a resin-like segment... an organohydrogenpolysiloxane (B)... and an addition reaction catalyst (C)...
Data Source
AI summary
An addition curable silicone resin composition for a light emitting diode is provided The composition includes an organopolysiloxane that includes a straight-chain segment represented by a formula: -(R12SiO)n- wherein, R1 is an unsaturated aliphatic bonding-free monovalent hydrocarbon group, and n is an integer of 1 or greater, and a resin-like segment consisting of R23SiO1/2 units wherein, R2 is a monovalent hydrocarbon group, an alkoxy group, or a hydroxyl group, SiO2 units, and/or R2SiO3/2 units wherein, R2 is as defined above, in which at least two of all the R2 groups are alkenyl groups. The composition exhibits strong resistance to thermal shock, and is resistant to cracking even under severe temperature cycling.