Branched Thiol Epoxy Curing Agent for Pot Life and Stability
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Solution Overview
Problem
Conventional epoxy resin curing agents with thiol groups have short pot life and poor storage stability, leading to restricted working conditions and potential premature curing during storage, which limits their application in forming products with good water resistance and hardness.
Innovation Solution
A thiol compound with a branch on a carbon atom at the α-position to a thiol group is used as the curing agent, which extends pot life and provides excellent storage stability, and when combined with a thiol compound having hydroxyl groups, allows for controlled pot life adjustment, resulting in an epoxy resin composition that forms products with enhanced water resistance and hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional polythiol-based curing agents are used, then excellent curability at low temperatures is achieved, but pot life becomes extremely short (3-5 minutes) and curing is initiated during composition preparation
Solution Approach 1:
The invention changes the chemical structure parameter of the thiol compound by introducing a bulky group at the α-position to the thiol group. This structural modification reduces the reactivity of the thiol group, thereby extending the pot life from 3-5 minutes to a usable duration while maintaining low-temperature curability. The bulky group creates steric hindrance that slows down the reaction rate without preventing the curing reaction entirely.
2Productivity
If primary thiol compounds are used as curing agents, then curing is accelerated by amine catalysts, but pot life becomes so short that working conditions are restricted
Solution Approach 1:
The invention modifies the chemical structure by adding a bulky group at the α-position to the thiol group, which changes the reactivity parameter. This structural change reduces the reaction rate to an controllable level, allowing sufficient working time while still enabling curing. The modification balances the curing rate and pot life, making the material workable without sacrificing ultimate cure performance.
3Productivity
If thiol compounds with high reactivity are used, then curing efficiency is improved, but storage stability deteriorates due to premature curing during storage
Solution Approach 1:
The invention changes the chemical structure by introducing a bulky group at the α-position to the thiol group, which reduces the reactivity parameter. This structural modification prevents premature curing during storage by slowing down the reaction rate, thereby improving storage stability. The reduced reactivity is acceptable because the curing reaction can still proceed to completion under appropriate curing conditions, maintaining curing efficiency.
4Reliability
If conventional thiol compounds are used, then curability is achieved, but the cured product lacks sufficient water resistance and hardness
Solution Approach 1:
The invention uses a composite approach by combining the thiol compound with a specific epoxy resin system. The bulky group-containing thiol compound reacts with the epoxy resin to form a crosslinked network structure that provides both curability and enhanced properties. The specific structure of the thiol compound contributes to forming a dense crosslinked network that improves water resistance and hardness of the cured product.
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 proposed solution provides an epoxy resin curing agent with a favorable pot life and storage stability, enabling the production of cured products with improved water resistance and hardness, while reducing odor and improving workability.
Implementation Method 1
Compounds having two or more thiol groups in one molecule readily react with epoxy resins, urethane resins or the like by mixing them with such resins and become cured products
Data Source
AI summary
It is an object of the present invention to provide an epoxy resin curing agent which has a favorable pot life and good storage stability as a curing agent for epoxy resins and from which an epoxy resin cured product having good water resistance and hardness is obtained through curing. The present invention is an epoxy resin curing agent containing a secondary or tertiary branched thiol compound having a substituent on a carbon atom at the α-position to a thiol group, and is also an epoxy resin composition comprising a polyvalent epoxy compound and the epoxy resin curing agent.