Methyl-Substituted Aliphatic Polyamines for Epoxy Curing
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Solution Overview
Problem
There is a need for amino curing agents that combine long pot life and low mixed viscosity at room temperature with high glass transition temperatures and good mechanical properties, while also enabling rapid curing at moderate temperatures for the production of composites, particularly large ones like wind rotor blades.
Innovation Solution
The development of new epoxy resin compositions using methyl-substituted alkyleneamines as amino curing agents, which provide a balance of rapid curing at moderate temperatures, long pot life, low viscosity at room temperature, and high glass transition temperatures, similar to cycloaliphatic amino curing agents like IPDA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aliphatic amines are used as curing agents, then curing rate is improved, but pot life deteriorates
Solution Approach 1:
The patent modifies the molecular structure of aliphatic amines by introducing methyl substituents at specific positions (2-methyl, 2,2-dimethyl, or 2-ethyl) within the polyamine chain. This structural parameter change enables the curing agent to achieve both rapid curing at moderate temperatures and extended pot life at room temperature, resolving the contradiction between curing rate and pot life duration
Solution Approach 2:
The invention creates a composite curing agent system by combining multiple amine functional groups within a single molecular structure. The polyamine molecules contain both primary and secondary amine groups arranged in specific sequences, creating a composite functional structure that simultaneously provides high reactivity and long processing time
2Duration of action of moving object
If cycloaliphatic amines are used as curing agents, then pot life is improved, but curing rate deteriorates
Solution Approach 1:
The patent changes the chemical structure from conventional cycloaliphatic amines to aliphatic polyamines with specific methyl substitutions. This structural parameter modification allows the curing agent to maintain the long pot life characteristic of cycloaliphatic amines while achieving the rapid curing rate of aliphatic amines
3Strength
If aromatic amines are used as curing agents, then adhesion is improved, but curing rate deteriorates
Solution Approach 1:
The invention changes the chemical class from aromatic amines to aliphatic polyamines with specific methyl substitutions. This parameter change maintains the adhesion properties typically associated with aromatic amines while achieving the rapid curing rates of aliphatic 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
These new epoxy resin compositions achieve rapid curing at moderate temperatures (50-120°C) with long pot life and low viscosity at room temperature, resulting in composites with high glass transition temperatures and good mechanical properties, making them suitable for large composite structures.
Implementation Method 1
Typical curing agents for epoxy resins are polyamines which bring about a polyaddition reaction (chain extension)
Data Source
AI summary
Aliphatic polyamines with methyl substituents are used in the curing of epoxy resins. The preparation of such aliphatic polyamines is described. Corresponding epoxy resin compositions include an epoxy resin and the aliphatic polyamines as curing agents. These curing agents combine comparably rapid curing at moderately elevated temperatures with comparably long pot life at room temperature. At the same time, they allow for cured epoxy resins with good mechanical properties and high glass transition temperature.