Etheramine Mixture Curing Epoxy Resins
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Solution Overview
Problem
Current polyetheramine curing agents for epoxy resins offer good flexibility but compromise thermal properties, and require high temperatures and long curing times, leading to inefficient manufacturing processes.
Innovation Solution
A process involving the alkoxylation of 1,4-cyclohexanedimethanol with propylene oxide followed by reductive amination to produce an etheramine mixture with a high monoether amine content, which is then used to cure epoxy resins, resulting in improved thermal stability and reduced curing times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If polyetheramines are produced by conventional reductive amination of polyoxyalkylene polyols, then flexibility is improved in the cured resin, but thermal properties deteriorate significantly
Solution Approach 1:
The patent applies local quality by incorporating rigid cyclic segments (cycloaliphatic structures from 1,4-cyclohexanedimethanol) at specific positions within the polyetheramine chain, rather than using uniform flexible polyether backbones. This creates a heterogeneous structure where rigid segments provide thermal stability while flexible polyether segments maintain chain flexibility, resolving the contradiction between flexibility and thermal properties
Solution Approach 2:
The patent creates a composite molecular structure combining flexible polyether chains with rigid cycloaliphatic rings. The resulting polyetheramine contains both flexible segments (from propylene oxide units) and rigid segments (from cyclohexane rings), effectively combining the beneficial properties of both structural elements to achieve both flexibility and thermal stability
2Strength
If conventional hardener systems with cycloaliphatic diamines are used, then cure strength is achieved, but high temperatures (70-80°C) and long curing times (3-4 hours) are required
Solution Approach 1:
The patent changes the chemical parameters of the curing agent by introducing polyetheramine structures with cycloaliphatic rings, which have different reactivity and curing characteristics compared to conventional cycloaliphatic diamines. This parameter change enables effective curing at lower temperatures (ambient to 50-60°C) and shorter times (1-2 hours) while maintaining cure strength
Solution Approach 2:
The patent introduces functional diversity by incorporating both primary and secondary amine groups in specific ratios within the polyetheramine structure. This local variation in functional groups provides multiple curing pathways that proceed at different rates and temperatures, enabling complete curing at lower temperatures and shorter times while maintaining strength
3Temperature
If diols such as diethylene glycol and dipropylene glycol are used to reduce polyether groups, then thermal properties improve, but unwanted intramolecular side reactions occur forming secondary amines
Solution Approach 1:
The patent extracts the problematic polyether backbone structure from the starting material and replaces it with cycloaliphatic diol (1,4-cyclohexanedimethanol) that contains minimal or no polyether groups. This removal of the polyether backbone eliminates the source of unwanted intramolecular side reactions while maintaining the desired thermal properties through the rigid cyclic structure
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 process yields a cured epoxy resin system with enhanced thermal stability, flexibility, and faster curing at lower temperatures, reducing energy costs and manufacturing time.
Implementation Method 1
contacting the initiator with propylene oxide in the alkoxylation reaction zone to provide a precursor polyol
Implementation Method 2
charging the precursor polyol to a reductive amination zone and reductively aminating the precursor polyol in the presence of a reductive amination catalyst, hydrogen and ammonia to form the etheramine mixture
Data Source
AI summary
The present invention relates to an etheramine mixture containing a monoether diamine and its method of production by alkyloxating an initiator with an alkylene oxide to produce a precursor polyol and reductively aminating the precursor polyol to form the etheramine mixture. The etheramine mixture may be used in variety of applications including as a curing agent for an epoxy resin or as a reactant in the production of polyurea materials.