Silicone-Modified Epoxy Resin for LED Sealing

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Solution Overview

Problem

Conventional silicone resin compositions for photosemiconductor element sealing exhibit high gas permeability and inadequate adhesiveness, making them unsuitable for applications requiring low gas permeability and mechanical strength, especially with the increasing luminance and output power of LED elements.

Innovation Solution

A silicone-modified epoxy resin composition is developed, represented by specific chemical formulas and obtained through addition reactions and oxidative epoxidation processes, incorporating a cyclic silicone-modified epoxy resin with a preferred structure and curing agents like amine-based or acid anhydride-based curing agents, to achieve low gas permeability and excellent mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If silicone resin is used to achieve flexibility and UV resistance, then the cured product has flexibility and does not absorb UV radiation, but gas permeability increases significantly

Engineering Contradiction:
ImproveUV resistanceVSAvoidgas permeability
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The invention uses a composite material system combining silicone resin with specific epoxy resins (aromatic glycidyl ether compound and alicyclic epoxy compound) to achieve both UV resistance from the silicone component and low gas permeability from the epoxy network structure. The synergistic combination allows the cured product to maintain flexibility while reducing gas permeability to acceptable levels for LED sealing applications.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If silicone content is increased to improve flexibility, then the cured product has better flexibility, but gas permeability becomes even higher and adhesiveness deteriorates

Engineering Contradiction:
ImproveflexibilityVSAvoidgas permeability
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The invention optimizes the silicone content within a specific range (5-50 mass%) to balance flexibility and gas permeability. Additionally, it controls the ratio between aromatic glycidyl ether compound and alicyclic epoxy compound, and selects specific molecular weight ranges for the epoxy resins to achieve the desired parameter combination of flexibility, low gas permeability, and adequate adhesiveness simultaneously.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

By creating a composite system with controlled composition ratios, the invention achieves a balance where the silicone provides flexibility and UV resistance while the epoxy resin network maintains structural integrity and reduces gas permeability, preventing the proportional increase in gas permeability that occurs with higher silicone content.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If conventional epoxy resin is used to achieve low gas permeability, then gas permeability is reduced, but the cured product suffers from discoloration and cracking under LED heat and light

Engineering Contradiction:
Improvegas permeabilityVSAvoidresistance to discoloration and cracking
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention creates a composite cured product containing both silicone resin and epoxy resin components. The silicone resin portion provides UV resistance and thermal stability that prevents discoloration and cracking under LED operation conditions, while the epoxy resin network maintains low gas permeability. This composite structure allows the material to withstand the combined stress of heat, light, and electrical properties of high-power LEDs.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention selects specific parameter ranges for the epoxy resin components (molecular weight, structural type) and silicone content to optimize the balance between gas permeability and resistance to environmental degradation. The aromatic glycidyl ether compound with specific structural parameters provides both low gas permeability and thermal stability, while the alicyclic epoxy compound contributes to flexibility and crack resistance.

Inventive Principle:
Principle #35Parameter changes

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 silicone-modified epoxy resin composition provides a cured product with low gas permeability and enhanced mechanical strength, addressing the limitations of conventional silicone resins and maintaining heat-resistant transparency.

Implementation Method 1

the silicone-modified epoxy resin is an addition reaction product between a compound represented by the following Formula (3) and a compound represented by the following Formula (4)

Methodology Applied
Scientific EffectAddition reaction: Chemical Bonding

Implementation Method 2

the silicone-modified epoxy resin is obtained by oxidizing a polyvalent olefin-based compound represented by the following Formula (5)

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentUS9963542B2Silicone-modified epoxy resin, composition containing the epoxy resin, and cured product of same
Publication Date: 2018.05.08 SHIN ETSU CHEMICAL CO LTD

AI summary

A silicone-modified epoxy resin which yields a cured product having low gas permeability and excellent strength; a composition of the silicone-modified epoxy resin; and an epoxy resin cured product obtainable by curing the composition, are provided.An epoxy resin represented by the following Formula (1):wherein R1 represents a hydrocarbon group having 1 to 6 carbon atoms; X represents an organic group having a norbornane epoxy structure, or a hydrocarbon group having 1 to 6 carbon atoms; n represents an integer from 1 to 3; plural R1s and plural Xs present in the formula may be respectively identical or different; and two or more of plural Xs represent an organic group having a norbornane epoxy structure.