Fluorene Epoxy Resin for LED Mounting Boards
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Solution Overview
Problem
Conventional LED-mounting printed wiring boards using epoxy resin laminates suffer from low heat resistance and light resistance, leading to discoloration and deterioration in reflectance, especially with the increasing brightness and output of LEDs, which is not adequately addressed by existing resin compositions.
Innovation Solution
A resin composition comprising a fluorene-containing epoxy resin, an acid anhydride of a completely or partially hydrogenated aromatic polycarboxylic acid, titanium dioxide, and a wet dispersing agent, along with an alicyclic epoxy resin, which provides improved heat resistance and optical reflectance, and is used to create a prepreg and metal foil-clad laminate suitable for LED applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If epoxy resin containing titanium dioxide is used for LED-mounting printed wiring board, then optical reflectance in ultraviolet and visible light regions is improved, but heat resistance deteriorates causing discoloration and reflectance loss under heat treatment
Solution Approach 1:
The patent uses a composite resin system combining fluorene-containing epoxy resin with alicyclic epoxy resin and acid anhydride curing agent. This composite approach creates a crosslinked network structure that provides both high optical reflectance (through titanium dioxide dispersion) and superior heat resistance (through the specific resin-curing agent combination), resolving the contradiction between optical performance and thermal stability.
Solution Approach 2:
The patent optimizes the chemical composition parameters by specifying precise ratios of fluorene-containing epoxy resin (30-80 parts), alicyclic epoxy resin (10-50 parts), and acid anhydride curing agent (10-40 parts) per 100 parts of fluorene-containing epoxy resin. This parameter optimization ensures the cured system achieves both high reflectance and heat resistance properties.
2Temperature
If bisphenol A novolac-based epoxy resin is used in large amount to improve heat resistance, then glass transition point increases, but optical reflectance and light resistance deteriorate
Solution Approach 1:
The patent changes the resin composition parameters by limiting bisphenol A novolac-based epoxy resin to 30-80 parts per 100 parts total resin, while introducing alicyclic epoxy resin (10-50 parts) and fluorene-containing epoxy resin (30-80 parts). This parameter adjustment maintains adequate heat resistance through the curing agent crosslinking while preserving optical reflectance properties through the titanium dioxide dispersion medium.
3Ease of manufacture
If conventional epoxy resin is used for LED mounting, then ease of manufacture is maintained, but deterioration under heat and light irradiation occurs reducing reflectance
Solution Approach 1:
The patent employs a composite curing system using acid anhydride as curing agent with fluorene-containing epoxy resin and alicyclic epoxy resin. This composite approach maintains conventional manufacturing processes (ease of manufacture) while achieving superior reliability under heat and light conditions through the specific chemical combination that prevents degradation and maintains reflectance.
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 effectively enhances heat resistance and optical reflectance, suppressing deterioration in reflectance when subjected to heat and light, making it suitable for high-performance LED-mounting printed wiring boards with improved industrial practicality.
Implementation Method 1
exhibits high optical reflectance in an ultraviolet light region and a visible light region
Implementation Method 2
a cured product having a high glass transition point
Implementation Method 3
a wet dispersing agent
Data Source
AI summary
There are provided a resin composition which has excellent heat resistance, exhibits 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 can be used suitably for an LED-mounting printed wiring board; a prepreg containing the resin composition; and a metal foil-clad laminate containing the resin composition, or the like. The resin composition of the present invention contains a fluorene-containing epoxy resin (A) having a specific structure, an acid anhydride (B) of a completely or partially hydrogenated product of an aromatic polycarboxylic acid, titanium dioxide (C), and a wet dispersing agent (D).