Epoxy Thiol Resin Stabilization via Metal Nanoparticle Catalyst Sequestration
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Solution Overview
Problem
Conventional one-part epoxy/polythiol compositions have short pot lives and instability at room temperature, limiting their application in the electronics industry where precise and extended bonding processes are required, and they often require high-temperature curing, which can damage electronic components.
Innovation Solution
A curable, one-part epoxy/thiol resin composition is developed, incorporating an epoxy resin with multiple epoxide groups, a polythiol compound with primary thiol groups, and a nitrogen-containing catalyst, along with metal nanoparticles like silver or copper, which are dispersed in the mixture to enhance stability and allow for low-temperature curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional one-part epoxy/polythiol compositions are used, then the composition is simple to formulate, but the pot life is short and storage stability is poor
Solution Approach 1:
Metal nanoparticles act as an intermediary between the epoxy resin and the amine catalyst. The nanoparticles absorb the catalyst at room temperature, preventing premature reaction and extending pot life. Upon heating, the catalyst is released to initiate curing. This mediator approach resolves the contradiction by allowing both extended stability and extended pot life.
Solution Approach 2:
The invention changes the physical state and reactivity parameters of the amine catalyst by incorporating it into metal nanoparticle structures. At room temperature, the catalyst is sequestered in the nanoparticle structure, providing stability and extended pot life. When heated to elevated temperatures, the catalyst is released and becomes reactive, enabling curing. This parameter change resolves the contradiction between stability and reactivity.
2Reliability
If high-temperature curing is used to achieve complete cure, then the curing is effective, but electronic components are damaged
Solution Approach 1:
The curing process utilizes periodic thermal action - the composition is stored and handled at room temperature for extended periods, then subjected to a brief elevated temperature treatment to initiate curing. The metal nanoparticles enable this periodic approach by providing catalyst sequestration at low temperature and controlled release at elevated temperature, achieving complete cure with minimal thermal exposure.
Solution Approach 2:
The invention changes the temperature parameter at which curing occurs by using metal nanoparticles to control catalyst release. Instead of requiring continuous high-temperature processing, the nanoparticles enable curing to be initiated at elevated temperatures after extended room-temperature stability, reducing thermal damage to electronic components while achieving complete cure.
3Duration of action of moving object
If the amine catalyst is added to extend pot life, then the working time is increased, but the composition becomes unstable at room temperature
Solution Approach 1:
Metal nanoparticles serve as an intermediary carrier for the amine catalyst. The nanoparticles provide a structure that holds the catalyst in a non-reactive state at room temperature, preventing instability and premature curing. This intermediary approach allows the catalyst to be present in the composition for extended periods without compromising stability, thereby extending working time while maintaining room temperature stability.
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 exhibits improved storage stability at room temperature, extended pot life, and rapid curing at elevated temperatures, making it suitable for precise bonding in the electronics industry without the need for high-temperature processing, thus maintaining component integrity.
Implementation Method 1
The composition comprises an epoxy resin, a polythiol curing agent, a nitrogen-containing catalyst, and metal nanoparticles. The metal nanoparticles stabilize the composition by interacting with the catalyst at room temperature.
Implementation Method 2
Upon heating to an elevated temperature, the nitrogen-containing catalyst is released from the metal nanoparticles, initiating rapid curing of the epoxy resin.
Implementation Method 3
The nitrogen-containing catalyst initiates curing of the epoxy resin when released from metal nanoparticles upon heating.
Data Source
AI summary
The present disclosure provides a curable, one-part epoxy/thiol resin composition. The composition comprises an epoxy/thiol resin mixture including: an epoxy resin component including an epoxy resin having at least two epoxide groups per molecule, a thiol component including a polythiol compound having at least two primary thiol groups, and a nitrogen- containing catalyst for the epoxy resin. The epoxy/thiol resin mixture further includes metal nanoparticles (e.g., silver nanoparticles, copper nanoparticles, or both), dispersed in the epoxy/thiol resin mixture. The present disclosure provides a method of curing a curable, one-part epoxy/thiol resin composition, including providing a curable, one-part epoxy/thiol resin composition and heating the composition to a temperature of at least 50°C.