Polyamide Curing Agent Composition for Epoxy Resins
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Solution Overview
Problem
The increasing cost of triethylenetetramine (TETA) due to reduced production in the ethanolamine manufacturing process necessitates the development of more economical alternatives for polyamide curing agents in epoxy resin applications, while maintaining molecular weight, viscosity, and chemical structure similarities to TETA to avoid formulation difficulties in coatings and adhesives.
Innovation Solution
A polyamide curing agent composition is created using a mixture of mono-, di-, tri-, and tetra-substituted amines with a specific parts by weight ratio, reacting with dimer fatty acids or esters, and incorporating at least 15 mole% tetrahydropyrimidine components, which provides faster cure speeds and physical properties similar to TETA-based polyamides without using TETA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If triethylenetetramine (TETA) is used as the amine component in polyamide curing agents, then the desired molecular weight, viscosity, and chemical structure are achieved, but the manufacturing cost increases due to reduced production in the ethanolamine manufacturing process
Solution Approach 1:
The patent segments the amine component into a mixture of multiple substituted amines (mono-, di-, tri-, and tetra-substituted) rather than using a single amine component. This segmentation allows the formulation to achieve the desired average molecular weight, viscosity, and chemical structure properties equivalent to TETA-based polyamides, while using a more cost-effective blend of amine components that are more readily available from ethanolamine manufacturing processes.
2Ease of manufacture
If an alternative amine to TETA is used to reduce cost, then manufacturing cost decreases, but formulation difficulties arise due to differences in molecular weight, viscosity, and chemical structure
Solution Approach 1:
The patent carefully controls and adjusts the parameters of the amine mixture, specifically the proportions of mono-, di-, tri-, and tetra-substituted amines, to achieve an average molecular weight, amine hydrogen functionality, and viscosity that closely match those of TETA-based polyamides. This parameter optimization ensures that the alternative amine mixture maintains compatibility with existing epoxy resin formulations while realizing cost savings.
Solution Approach 2:
The patent creates a composite amine system by combining multiple types of substituted amines in specific ratios. This composite approach allows the formulation to leverage the beneficial properties of each amine type while achieving overall performance equivalent to TETA, thereby maintaining formulation compatibility across different epoxy resin systems without relying on a single expensive amine component.
3Device complexity
If conventional polyamide curing agents are used, then formulation simplicity is maintained, but cure speed is slower compared to the new composition
Solution Approach 1:
The patent introduces tetrahydropyrimidine components (at least 15 mole%) as a specialized functional ingredient within the polyamide curing agent formulation. This local enhancement of specific chemical functionality accelerates the epoxy curing reaction without requiring a complete reformulation of the base polyamide system. The tetrahydropyrimidine acts as a catalyst or reactive accelerator, providing faster cure speeds while the rest of the formulation maintains its simplicity and compatibility with standard epoxy resin systems.
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 offers faster cure speeds, maintains desirable physical properties, and allows for the production of coatings and adhesives with improved dry times and appearance, specifically achieving dry-through times of less than 24 hours, thus addressing the economic and formulation challenges posed by the rising cost of TETA.
Implementation Method 1
polyamide curing agent compositions comprising the reaction product of (1) an amine component comprising at least one multifunctional amine... with (2) a dimer fatty acid or ester component
Implementation Method 2
incorporating at least 15 mole% tetrahydropyrimidine components, which provides faster cure speeds
Data Source
AI summary
The present invention provides polyamide curing agent compositions comprising the reaction products of (1) multifunctional amines of structure 1 where R1 is CH2CH2CH2NH2; R2 , R3 and R4 independently are H or CH2CH2CH2NH2, and X is CH2CH2 or CH2CH2CH2 with (2) dimer fatty acids, optionally in combination with monofunctional fatty acids, the reaction product preferably comprising at least 15 wt% tetrahydropyrimidine-containing components. The curing agent compositions are useful for crosslinking epoxy resins to produce coatings, adhesives, floorings, composites and other articles.