Etheramine Mixture Curing Epoxy Resins at Lower Temperatures
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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 for curing, leading to slower manufacturing times and energy inefficiencies.
Innovation Solution
An etheramine mixture containing at least 10% monoether amine, produced by alkoxylation and reductive amination, which provides improved thermal stability and allows for curing at lower temperatures or shorter times, minimizing unwanted side reactions and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If polyether groups are used in the polyol backbone to provide flexibility, then flexibility is improved, but thermal properties deteriorate
Solution Approach 1:
The patent extracts and eliminates polyether groups from the polyol backbone structure. By using initiators without polyether groups (such as glycols, polyols, or polyamines without polyether linkages) and performing reductive amination to convert hydroxyl groups to amine groups, the invention produces polyamino polyalkylene ethers that lack the problematic polyether backbone segments while retaining the desired flexibility from the alkylene ether side chains.
2Reliability
If high temperatures are used for curing epoxy resins, then cure performance is improved, but manufacturing time and energy consumption increase
Solution Approach 1:
The patent changes the chemical parameters of the curing agent by introducing primary amine groups through reductive amination. These primary amine groups react more rapidly with epoxy groups than secondary amines or polyether groups, enabling the curing process to proceed effectively at lower temperatures (reducing heating time from 3-4 hours to shorter durations) while maintaining or improving cure performance.
3Temperature
If diethylene glycol or dipropylene glycol are used to reduce polyether groups, then thermal properties are improved, but unwanted side reactions occur forming secondary amines
Solution Approach 1:
The patent uses an intermediary process step of reductive amination with controlled conditions. By employing specific catalysts (such as Raney nickel or copper chromite) and controlling the reaction conditions (temperature, pressure, ammonia-to-polyol ratio), the invention mediates the conversion of hydroxyl groups to primary amine groups while suppressing intramolecular cyclization reactions that would form unwanted secondary amines like morpholine.
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 etheramine mixture achieves enhanced thermal stability and faster cure performance, reducing manufacturing time and energy costs while maintaining flexibility in cured resin products.
Implementation Method 1
reductively aminating the hydroxyl groups on the precursor polyol to form the etheramine mixture
Implementation Method 2
in the presence of a reductive amination catalyst
Data Source
AI summary
The present invention relates to an etheramine mixture containing a monoether diamine and its method of production by alkoxylating 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.