Solvent-Free Curing Agent for Aqueous Epoxy Resins
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Solution Overview
Problem
Conventional epoxy resin curing agents require significant amounts of organic solvents, leading to health and environmental concerns due to volatile organic compounds (VOCs), and there is a need for a water-compatible, solvent-free alternative with good performance.
Innovation Solution
A method involving an esterification step between a polyhydric alcohol and a polyanhydride, followed by a chain extension reaction with a bifunctional epoxy resin, and subsequent reaction with a polyamine compound, culminating in an end-capping step with a monofunctional epoxy, all without the addition of volatile organic compounds, to produce a curing agent suitable for aqueous epoxy resin coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional epoxy resin curing agents are used, then good curing performance is achieved, but large amounts of organic solvents must be added leading to high VOC emissions
Solution Approach 1:
The patent changes the chemical composition parameters of the curing agent by incorporating polyhydric alcohols (ethylene glycol, propylene glycol) and polyamines in specific ratios, enabling the formulation of a water-compatible curing agent that eliminates organic solvents while maintaining curing performance
Solution Approach 2:
The patent creates a composite curing agent system combining polyhydric alcohols, polyamines, and epoxy resins in a water-based formulation, achieving both environmental compatibility and effective curing performance without relying on conventional organic solvent systems
2Reliability
If organic solvents are used to dissolve epoxy resin, then good adhesion and mechanical properties are achieved, but health and environmental pollution issues arise
Solution Approach 1:
The patent modifies the solvent parameter from organic solvents to water-based system by adjusting the chemical composition to include polyhydric alcohols and polyamines that are compatible with aqueous epoxy resins, maintaining adhesion performance while eliminating environmental pollution
Solution Approach 2:
The patent replaces expensive and harmful organic solvents with water and readily available polyhydric alcohols, creating a more environmentally friendly formulation that achieves the same functional results without the harmful side effects
3Object-affected harmful factors
If water-compatible curing agents are developed, then VOC emissions are reduced, but curing performance and compatibility with epoxy resins may be compromised
Solution Approach 1:
The patent optimizes the molecular weight, hydroxyl value, and amine content parameters of the polyhydric alcohols and polyamines to ensure that the water-compatible curing agent achieves the same curing performance as conventional organic-based agents, eliminating the performance compromise typically associated with water-based formulations
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
This method enables the production of a water-compatible, solvent-free curing agent that effectively cures aqueous epoxy resins without additional VOCs, maintaining good performance and compatibility with epoxy resins, allowing for curing at room temperature or elevated temperatures.
Implementation Method 1
mixing a polyhydric alcohol with a polyanhydride in an equivalent ratio of 1.1:1 for an esterification reaction to obtain an ester-based emulsifier
Implementation Method 2
mixing the ester-based emulsifier (A) with a bifunctional epoxy resin in an equivalent ratio of 0.05:1 for a chain extension to obtain a polymer intermediate
Implementation Method 3
mixing and reacting the polymer intermediate (B) and a polyamine compound in an equivalent ratio of 0.2:1 to obtain a curing agent
Data Source
AI summary
A curing agent and method for producing the same are provided, the method includes: esterification reaction: reacting a polyhydric alcohol with a polybasic acid anhydride to obtain an ester-based emulsifier (A); chain extension reaction: reacting an ester-based emulsifier (A) with a bifunctional epoxy resin to obtain a polymer intermediate (B); and reacting the polymer intermediate (B) with a polyamine compound to obtain a curing agent (C).