Dual-Curable Epoxy Composition for Shadow-Area Bond Curing
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Solution Overview
Problem
Existing actinic radiation curable adhesive compositions form less than ideal bonds in shadow areas due to incomplete curing, which can weaken the adhesive over time, especially in temperature-sensitive components like optical display assemblies and circuit board edgebonding, as they lack both moisture and UV curable functionalities in the same molecules.
Innovation Solution
A dual curable epoxy composition that can be cured by actinic radiation and moisture, comprising an alkoxysilane and epoxy functional oligomer, a photoinitiator, and a catalyst, allowing for complete curing in shadow areas through a combination of UV exposure and moisture absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If actinic radiation curable adhesive compositions are used, then curing speed is improved, but shadow areas remain uncured and bond strength deteriorates
Solution Approach 1:
The patent combines actinic radiation curable groups (acrylate, epoxy) and moisture curable groups (alkoxysilane) within the same oligomer molecule. This merging allows the adhesive to be cured by UV light in exposed areas while simultaneously being curable by moisture in shadow areas, eliminating the uncured residue problem and ensuring complete bonding throughout.
Solution Approach 2:
The oligomer is designed with multi-functionality, containing both actinic radiation responsive groups and moisture curable groups. This universal design enables the same adhesive composition to respond to two different curing mechanisms (UV irradiation and moisture exposure), ensuring complete curing regardless of light penetration, thereby improving both curing speed and bond reliability.
2Reliability
If heat curing is used to cure shadow areas, then complete curing is achieved, but temperature sensitive components are damaged
Solution Approach 1:
The patent changes the curing parameter from thermal energy (heat) to chemical energy (moisture). By incorporating moisture curable alkoxysilane groups that react with ambient moisture, the system achieves complete curing in shadow areas without requiring heat input, thus avoiding thermal damage to temperature-sensitive components while ensuring complete curing.
3Adaptability or versatility
If separate moisture curable and UV curable functionalities are used in different molecules, then both curing mechanisms are present, but incomplete curing occurs in specific areas
Solution Approach 1:
The patent merges moisture curable alkoxysilane groups and actinic radiation curable groups (acrylate/epoxy) within the same oligomer molecule. This molecular-level integration ensures that every molecule in the adhesive composition possesses both curing capabilities, guaranteeing complete curing throughout the adhesive layer regardless of light penetration, thereby achieving both versatility and manufacturing precision.
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 dual curing mechanism ensures thorough cross-linking, enhancing bond strength and stability, avoiding the use of heat-sensitive components and reducing manufacturing complexity by eliminating the need for heat curing.
Implementation Method 1
capable of polymerization or cross-linking by exposure to actinic radiation
Implementation Method 2
at least one component (A) with alpha-(alkoxy)silane groups
Data Source
AI summary
Actinic radiation and moisture dual curable epoxy compositions and methods of curing such compositions are disclosed. The compositions comprise an alkoxysilane and epoxy dual functional oligomer comprising a functional group curable by actinic radiation, a functional group curable by moisture, and a functional group chemically linking the functional group curable by actinic radiation and the functional group curable by moisture; catalyst configured to react with the functional group curable by moisture in the presence of water; and at least one photoinitiator. The compositions are particularly useful for wearable electronics and medical devices. In some embodiments, unexpected results are obtained in the ability to use cationic photoinitiators and/or in avoiding the need for acrylates and/or heat curing.