Multifunctional Amine Aqueous Dispersion for Epoxy Curing
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Solution Overview
Problem
Aqueous dispersions of multifunctional primary amines face challenges in providing effective curing agents for epoxy resins, including low solid content and inadequate water resistance, while also requiring compatibility with epoxy resins and acting as emulsifiers to avoid internal hydrophilization.
Innovation Solution
An aqueous dispersion comprising a multifunctional amine with multiple primary amino groups and a non-ionic emulsifier, where the amine is derived from a compound with reactive groups such as epoxide groups, secondary amino groups, and other functional groups, allowing it to act as both a curing agent and emulsifier for epoxy resins, and is prepared through a multi-step process involving blocking and deblocking of primary amino groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multifunctional primary amines are used as curing agents for epoxy resins, then curing speed and reaction efficiency are improved, but compatibility with epoxy resins deteriorates and health hazards increase
Solution Approach 1:
The patent segments the multifunctional primary amine molecule into distinct functional regions: hydrophobic moieties that ensure compatibility with epoxy resins, primary amino groups that provide curing activity, and secondary amino groups that contribute to crosslinking. This segmentation allows each part to fulfill its specific function without compromising the others.
Solution Approach 2:
The patent applies local quality by creating molecules with specific local characteristics: hydrophobic regions for epoxy compatibility, reactive primary amine regions for curing, and secondary amine regions for additional crosslinking. This localized functional distribution resolves the contradiction between reactivity and compatibility.
2Ease of operation
If hydrophilic modification is introduced to improve water dispersibility, then ease of operation is improved, but water resistance of the coating deteriorates
Solution Approach 1:
The patent uses secondary amino groups as intermediaries that bridge the hydrophobic epoxy resin and the hydrophilic primary amine groups. These secondary amines provide controlled hydrophilicity for water dispersibility while maintaining the hydrophobic character needed for water resistance through the epoxy network.
Solution Approach 2:
The patent carefully controls the parameters of the amine molecule, specifically the ratio and positioning of primary versus secondary amino groups, to achieve optimal balance between water dispersibility and water resistance. By adjusting these molecular parameters, both requirements are satisfied simultaneously.
3Device complexity
If monomeric amines are used to simplify the system, then device complexity is reduced, but compatibility with epoxy resins deteriorates
Solution Approach 1:
The patent creates composite amine molecules that combine multiple functional units (primary amines, secondary amines, hydrophobic groups) into a single integrated curing agent structure. This molecular-level compositing achieves compatibility without requiring complex mixtures of separate components.
4Ease of manufacture
If strong acid catalysts are used for hydrophilic modification, then manufacturing capability is improved, but process control difficulty increases
Solution Approach 1:
The patent enables the amine molecule to self-regulate its hydrophilicity through the inherent properties of the secondary amino groups, eliminating the need for strong acid catalysts and complex hydrophilic modification processes. The molecule automatically achieves the desired balance between hydrophilicity and hydrophobicity.
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 solution achieves higher solid concentrations and improved water resistance of epoxy coatings, enabling effective curing and emulsification of epoxy resins, thus addressing the limitations of previous multifunctional amine dispersions.
Implementation Method 1
Amine based curing agents for epoxy resins usually have primary, secondary, or also tertiary, amino groups that react with an epoxide group under formation of a beta-hydroxy amine structure or a betaine structure
Implementation Method 2
An aqueous dispersion comprising a multifunctional amine with multiple primary amino groups and a non-ionic emulsifier
Data Source
AI summary
The invention relates to a curing agent for epoxy resins which is an aqueous dispersion of a multifunctional amine AC having more than one primary amino group per molecule, and at least one moiety per molecule derived from the reaction of a compound C containing at least one reactive group which is preferably an epoxide group, with a molecule having at least one blocked primary amino group and at least one group which is reactive towards the at least one reactive group of compound C, which is selected from the group consisting of secondary amino groups >NH, of hydroxyl groups -OH, of mercaptan groups -SH, of amide groups -CO-NHR, where R can be hydrogen or an alkyl group having from one to twelve carbon atoms, of hydroxyester groups, and of acid groups, particularly of carboxyl groups -COOH, sulphonic acid groups -SO3H, and phosphonic acid groups- PO3H2, and preferably, also moieties which are compatible with an epoxy resin, as well as a process for its preparation, and a method of use thereof.