Optically Clear UV Thermal Curing Epoxy Composition
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Solution Overview
Problem
Epoxy compositions typically lack sufficient optical clarity to be used in applications requiring transparency, and they often yellow over time due to oxidation, necessitating the use of fillers and light-blocking components that compromise their optical properties.
Innovation Solution
A UV and thermally curable epoxy composition that maintains optical clarity by using a saturated epoxy-functionalized compound, a heat cure system with an alicyclic anhydride and cationic catalyst, and a cross-linking (meth)acrylate, along with a photoinitiator, which allows for initial UV curing and subsequent thermal curing, ensuring high optical transmittance and resistance to yellowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If inorganic fillers or pigments are added to epoxy compositions to modify viscosity and enhance physical properties, then strength and durability are improved, but optical clarity deteriorates
Solution Approach 1:
The invention extracts and eliminates inorganic fillers and pigments from the epoxy composition entirely, using only organic components that maintain optical clarity while providing necessary viscosity modification through molecular structure design rather than particulate additives
Solution Approach 2:
The invention changes the chemical parameters of the epoxy system by using saturated epoxy-functionalized compounds with specific molecular structures that provide inherent viscosity control without requiring inorganic fillers, thereby maintaining optical clarity while achieving desired mechanical properties
2Strength
If traditional epoxy materials and additives are used to achieve sufficient viscosity and adhesive properties, then adhesive strength is improved, but optical clarity and resistance to yellowing deteriorate
Solution Approach 1:
The invention changes the chemical composition parameters by exclusively using saturated epoxy-functionalized compounds and saturated cross-linking agents, eliminating unsaturated bonds that are prone to oxidation and yellowing, while maintaining adhesive strength through optimized molecular structure and cross-linking density
Solution Approach 2:
The invention creates a composite molecular structure combining saturated epoxy-functionalized compounds with saturated cross-linking agents and photoinitiators, forming a hybrid curing system that achieves both adhesive strength and optical stability without traditional problematic additives
3Ease of manufacture
If light-blocking components are incorporated to control viscosity and prevent migration, then adhesive deposition control is improved, but UV curing effectiveness deteriorates
Solution Approach 1:
The invention extracts and removes light-blocking components from the formulation, relying instead on the inherent viscosity characteristics of the saturated organic components and controlled cross-linking to prevent migration, thereby allowing UV light to penetrate effectively
Solution Approach 2:
The invention uses a photoinitiator system that enables preliminary UV curing to achieve rapid tackification and deposition control before final thermal curing, eliminating the need for light-blocking viscosity modifiers while maintaining manufacturing ease
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 achieves optical transmittance of at least 95% and a yellowness index of <1%, providing excellent optical clarity and chemical resistance while maintaining mechanical strength and flexibility, suitable for various optical applications.
Implementation Method 1
a photoinitiator; wherein the cured composition provides an optical transmittance of at least 95%
Implementation Method 2
a heat cure system including an alicyclic anhydride and a cationic catalyst
Data Source
AI summary
Adhesive compositions having optical clarity are disclosed. The compositions include saturated epoxy-functionalized compound; a heat cure system which includes an alicyclic anhydride and a cationic catalyst; a predominantly hydrophobic cross-linking (meth)acrylate in amounts sufficient to control the crosslinking density of the composition; and a photoinitiator to allow for initial fixturing of the composition prior to thermal cure. The compositions provide an optical transmittance of at least 95% and a yellowness (*b) of <1%.