Resin Composition for LED PCBs with High Optical Reflectance
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Solution Overview
Problem
Conventional laminates for LED-mounting printed wiring boards face issues with heat resistance, light resistance, and adhesion to metal foils, particularly when subjected to heat treatments and light irradiation, leading to discoloration and reflectance deterioration.
Innovation Solution
A resin composition comprising an aliphatic epoxy-modified silicone compound, a multibranched imide resin with an isocyanurate ring and carboxyl group, titanium dioxide, and a dispersing agent, which improves optical reflectance, heat resistance, and peel strength when used in prepregs and metal foil-clad laminates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If epoxy resin containing titanium dioxide is used for LED-mounting printed wiring board, then heat resistance is improved, but optical reflectance deteriorates remarkably due to discoloration from heat treatment and light irradiation
Solution Approach 1:
The invention uses a composite resin system combining phenolic resin and alicyclic epoxy resin, rather than conventional single-component epoxy resins. This composite material approach allows the phenolic resin to provide heat resistance while the alicyclic epoxy resin maintains optical properties, achieving both high heat resistance and high optical reflectance simultaneously
Solution Approach 2:
The invention changes the chemical composition parameters of the resin system by specifying phenolic resin content at 5-45 mass% and alicyclic epoxy resin content at 55-95 mass%. By optimizing these compositional parameters, the material achieves both high heat resistance (Tg of 130°C or higher) and high optical reflectance (80% or higher in visible light region)
2Ease of manufacture
If conventional epoxy resin laminate is used, then manufacturing is simple, but adhesion to metal foil deteriorates under heat and light exposure
Solution Approach 1:
The invention changes the chemical composition parameters by incorporating phenolic resin (5-45 mass%) which provides excellent adhesion properties. This compositional modification ensures high peel strength to copper foil (0.5 N/mm or higher after reflow) while maintaining ease of manufacture through a straightforward lamination process
3Object-affected harmful factors
If resin composition is optimized for high optical reflectance, then light resistance improves, but heat resistance deteriorates
Solution Approach 1:
The invention employs a composite resin system where alicyclic epoxy resin (55-95 mass%) provides high optical reflectance and light resistance, while phenolic resin (5-45 mass%) contributes heat resistance. This composite approach achieves both high light resistance (optical reflectance of 80% or higher) and high heat resistance (Tg of 130°C or higher) 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 resin composition maintains high optical reflectance and peel strength while resisting heat and light-induced deterioration, making it suitable for LED-mounting printed wiring boards with enhanced industrial practicality.
Implementation Method 1
a resin composition containing a bisphenol A novolac-based epoxy resin (A), an alicyclic epoxy resin (B), and titanium dioxide (C)... exhibits high optical reflectance in the ultraviolet light region and the visible light region
Implementation Method 2
undergoes less deterioration in optical reflectance when subjected to a heat treatment or a light irradiation treatment
Implementation Method 3
exhibits high optical reflectance in the ultraviolet light region and the visible light region, and undergoes less deterioration in optical reflectance when subjected to a heat treatment or a light irradiation treatment
Data Source
AI summary
There are provided a resin composition which has high optical reflectance in an ultraviolet light region and a visible light region, undergoes less deterioration in optical reflectance when subjected to a heat treatment and a light irradiation treatment, has an improved peel strength to a metal foil, has excellent heat resistance, and can be used suitably for an LED-mounting printed wiring board; and a prepreg and a metal foil-clad laminate using the same. The resin composition of the present invention comprises: an aliphatic epoxy-modified silicone compound (A); a multibranched imide resin (B) having an isocyanurate ring and a carboxyl group; titanium dioxide (C); and a dispersing agent (D).