Amine Functional Curing Agents for Epoxy Resins
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Solution Overview
Problem
Current epoxy curing agents face challenges with lower functionality polyetheramines leading to low glass transition temperatures, long gel times, and 'amine blushing' due to reaction with atmospheric CO2 and water, while high functionality amines result in short gel times and thermal degradation issues.
Innovation Solution
Development of amine functional agents with Amine Hydrogen Functionality (AHF) of at least 5 and Amine-Hydrogen Equivalent Weight (AHEW) of at least 50, formed from alkoxylated polyol compounds like erythritol, pentaerythritol, and Mannich polyols, which provide balanced reactivity and processing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If lower functionality polyetheramines are used as curing agents, then flexibility and working time are improved, but glass transition temperature decreases and amine blushing occurs
Solution Approach 1:
The patent changes the molecular parameters of the curing agent by using high functionality polyols (functionality 4 or higher) with controlled molecular weight and specific structural characteristics. This parameter optimization allows achieving adequate working time while maintaining higher glass transition temperatures and reducing amine blushing compared to conventional lower functionality polyetheramines.
2Productivity
If high functionality amines are used as curing agents, then gel time is reduced and reactivity is improved, but thermal degradation occurs due to high exotherm temperatures
Solution Approach 1:
The patent optimizes the molecular weight and functionality parameters of the polyol-based curing agent to achieve a balanced reactivity profile. The high functionality (≥4) provides adequate gel time and reactivity, while the controlled molecular weight and polyol structure moderate the exotherm temperature, preventing thermal degradation in thick sections.
3Strength
If high functionality amines are used as curing agents, then reactivity is improved, but thermal degradation and charring occur in thick sections
Solution Approach 1:
The patent modifies the chemical structure parameters of the curing agent by using polyols with functionality of 4 or higher and specific molecular weight ranges. This structural optimization maintains high reactivity for adequate gel time while the distributed functional groups and molecular architecture reduce peak exotherm temperatures, preventing charring and thermal degradation in thick composite sections.
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 agents offer desirable mechanical properties, reduced 'amine blushing', and controlled gelation, preventing thermal degradation and improving the handling and performance of epoxy resin systems.
Implementation Method 1
an amine functional agent having an Amine Hydrogen Functionality (AHF) of at least 5 and an Amine-Hydrogen Equivalent Weight (AHEW) of at least about 50 for curing epoxy resins
Implementation Method 2
the amine functional curing agent is formed from an alkoxylated polyol compound; and wherein the alkoxylated polyol compound has a polyol selected from: the group consisting of: erythritol, pentaerythritol, di-pentaerythritol, and combinations thereof
Data Source
AI summary
In another exemplary embodiment, an amine functional curing agent has an Amine Hydrogen Functionality (AHF) of at least 7 and an Amine-Hydrogen Equivalent Weight (AHEW) of at least about 50.