Epoxy Curing Agent Adduct for Low Viscosity and Fast Cure
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Solution Overview
Problem
Current curable compositions based on amine curing agents and epoxy resins face issues with high viscosity, leading to processing difficulties at room temperature, and excessive hydrate formation, which can result in surface defects and inadequate adhesion, while also posing environmental concerns due to solvent use.
Innovation Solution
A curing agent comprising an adduct formed by reacting ethylene diamine or polyethylene polyamine with monoglycidylether, isolated to minimize excess amine, combined with an amine compound like piperazine or isophorone diamine, allowing for low viscosity and reduced solvent use, enabling faster curing and improved surface properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional amine curing agents are used, then the curable compositions achieve sufficient mechanical and physical properties, but they exhibit high viscosity and excessive hydrate formation leading to surface defects
Solution Approach 1:
The curing agent is divided into two separate components: Component A (adduct of polyethylene polyamine with monoglycidylether) and Component B (amine compound with reactive amine hydrogen). This segmentation allows each component to contribute specific properties - Component A provides low viscosity and reduced hydrate formation, while Component B ensures adequate curing and mechanical properties.
Solution Approach 2:
The invention creates a composite curing agent system combining an adduct (Component A) with a specific amine compound (Component B). This composite approach leverages the advantages of both components: the adduct structure reduces viscosity and hydrate formation, while the amine compound maintains curing effectiveness and mechanical strength.
2Ease of operation
If the curable compositions are formulated to be processable at room temperature, then they achieve ease of operation, but they require high levels of diluents or solvents which deteriorate mechanical properties and create environmental issues
Solution Approach 1:
The invention changes the chemical structure parameters of the curing agent by using an adduct with specific molecular architecture and combining it with amine compounds having appropriate reactivity. This parameter optimization allows the composition to maintain low viscosity and good processability at room temperature without requiring excessive diluents, thereby preserving mechanical properties.
Solution Approach 2:
The invention extracts and removes the need for large amounts of diluents or solvents by optimizing the curing agent composition. The adduct-amine compound system inherently provides sufficient processability at room temperature through its molecular structure and reactivity characteristics, eliminating the harmful dependency on external diluents.
3Ease of operation
If larger portions of diluents are added to reduce viscosity, then the curable compositions become more processable, but the mechanical properties of the cured duromers deteriorate significantly
Solution Approach 1:
The invention changes the fundamental parameters of the curing system by using an adduct with optimized molecular weight and structure combined with specific amine compounds. This parameter optimization achieves the dual goal of low viscosity for easy processing and high crosslink density for excellent mechanical properties, eliminating the need for viscosity-reducing diluents.
4Reliability
If conventional curing agents are used, then adequate curing is achieved, but intense unpleasant odour and toxicological issues arise due to vapour pressure
Solution Approach 1:
The composite curing agent system combines an adduct with low vapour pressure and reduced odour characteristics with a complementary amine compound. This combination maintains effective curing (Reliability) while significantly reducing harmful emissions, odour, and toxicological issues compared to conventional amine curing agents.
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 results in lower viscosity curable compositions that can be processed at room temperature with minimal solvents, achieving faster curing rates and reduced hydrate formation, thereby enhancing mechanical and surface properties while minimizing environmental impact.
Implementation Method 1
an adduct obtainable by reaction of a1) ethylene diamine or polyethylene polyamine having up to five nitrogen atoms in the molecule, with a2) a monoglycidylether
Implementation Method 2
wherein the adduct of a1) and a2) is isolated by removing the excessive polyethylene polyamine or ethylene diamine respectively
Implementation Method 3
The inventive curing agents have comparatively low viscosities and enable processing at room temperature, thus in a range of 10 to 30°C, so that an addition of interfering solvents and/or softening agents may be basically set aside
Implementation Method 4
a curing agent for epoxy resins... achieving faster curing rates
Implementation Method 5
curable compositions additionally comprising an epoxy compound... achieving faster curing rates
Implementation Method 6
achieving faster curing rates and reduced hydrate formation, thereby enhancing mechanical and surface properties
Data Source
AI summary
Curing agent for epoxy resins, comprising: A) 1 - 99 wt% of an adduct obtainable by reaction of a1) a polyethylene polyamine having up to five nitrogen atoms in the molecule, with a2) a monoglycidylether, wherein the adduct of a1) and a2) is isolated by removing the excessive polyethylene-polyamine, and B) 99 - 1 wt% of an amine compound having at least two reactive amine hydrogen atoms in the molecule, as well as curable compositions additionally comprising an epoxy compound and the use of said curable compositions for the preparation of moulded articles and sheet materials, as well as for applications in the field of adhesives and sealing compounds.