Curable Silicone Composition for Thermal Aging Crack Resistance
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Solution Overview
Problem
Curable silicone compositions used in optical semiconductor devices experience weight reduction, hardness changes, and crack generation during thermal aging, reducing the reliability of high-intensity LEDs with high heat generation.
Innovation Solution
A curable silicone composition comprising a linear organopolysiloxane with at least two silicon-bonded alkenyl groups, an organopolysiloxane with specific siloxane units, and a hydrosilylation reaction catalyst, which forms a cured product with enhanced crack resistance and stability during thermal aging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional curable silicone compositions are used for LED sealing, then initial adhesion and curing properties are achieved, but weight reduction, hardness change, and crack generation occur during thermal aging
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating specific ratios of crosslinkable organopolysiloxane (5-50 wt%), organopolysiloxane with SiO 4/2 units (50-95 wt%), and organopolysiloxane with silicon-bonded hydrogen atoms (0.5-10 wt%). This parameter optimization ensures the cured product maintains compositional stability during thermal aging, preventing weight reduction while achieving reliable adhesion and crack resistance.
Solution Approach 2:
The patent creates a composite silicone system by combining three distinct polysiloxane components with complementary functions: crosslinkable organopolysiloxane for network formation, organopolysiloxane with SiO 4/2 units for structural stability and hardness control, and organopolysiloxane with silicon-bonded hydrogen atoms for crosslinking reactivity. This composite approach achieves both initial adhesion and long-term thermal aging resistance.
2Reliability
If conventional curable silicone compositions are used for LED sealing, then initial adhesion and curing properties are achieved, but weight reduction, hardness change, and crack generation occur during thermal aging
Solution Approach 1:
The patent optimizes the concentration parameter of SiO 4/2 units in the organopolysiloxane component (50-95 wt%) to control the cured product's hardness and its stability during thermal aging. This parameter adjustment ensures the material maintains appropriate hardness characteristics even after prolonged exposure to high temperatures, preventing both excessive softening and brittleness.
Solution Approach 2:
The composite system combines organopolysiloxane with SiO 4/2 units (providing structural rigidity and hardness stability) with crosslinkable organopolysiloxane (providing adhesion and flexibility). This material combination creates a balanced cured product that maintains hardness stability during thermal aging while achieving reliable initial adhesion.
3Reliability
If conventional curable silicone compositions are used for high-intensity LED sealing, then initial adhesion is achieved, but crack generation occurs during thermal aging
Solution Approach 1:
The patent adjusts the crosslinking density parameter by controlling the ratio of organopolysiloxane with silicon-bonded hydrogen atoms (0.5-10 wt%) to crosslinkable organopolysiloxane (5-50 wt%). This optimization ensures sufficient crosslinking for crack resistance while maintaining adequate flexural strength, preventing the material from becoming too brittle during thermal aging.
Solution Approach 2:
The patent creates a composite system where crosslinkable organopolysiloxane provides adhesion and flexibility, organopolysiloxane with SiO 4/2 units provides structural strength and crack resistance, and organopolysiloxane with silicon-bonded hydrogen atoms provides crosslinking reactivity. This composite approach achieves both crack resistance and flexural strength simultaneously.
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 forms a cured product with low weight reduction, hardness change, and crack generation after thermal aging, ensuring excellent reliability of optical semiconductor devices, particularly those with high heat generation.
Implementation Method 1
Curable silicone compositions that can be cured by a hydrosilylation reaction are cured to form a cured product with excellent electrical properties
Data Source
Figure 1
AI summary
The curable silicone composition of the present invention comprising: (A) a linear organopolysiloxane having at least two silicon atom-bonded alkenyl groups per molecule, wherein at least 5 mole% of all silicon atom-bonded organic groups are aryl groups; (B) an organopolysiloxane containing siloxane units represented by the formula: R13SiO1/2 (wherein R1 represents a monovalent hydrocarbon group) and siloxane units represented by the formula: SiO4/2, and the amount of alkenyl groups is at least 6 % by weight; (C) an organopolysiloxane having at least two silicon atom-bonded hydrogen atoms per molecule; and (D) a hydrosilylation reaction catalyst, forms a cured product with little weight reduction, little change in hardness, and little crack generation after thermal aging.