Dicyanamide Salt Epoxy Resin Composition for Storage Stability
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Solution Overview
Problem
Conventional epoxy resin compositions, particularly two-pack types, face challenges with short pot life and limited application in automatic machinery due to immediate mixing requirements, and existing one-pack types either have poor storage stability or require high temperatures for curing.
Innovation Solution
A specific dicyanamide salt is used as a curing agent in a one-pack epoxy resin composition, providing excellent storage stability and curability, allowing for ambient temperature application without the need for immediate mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a two-pack type epoxy resin composition is used, then curability at ambient or low temperature is achieved, but the pot life is short and immediate mixing is required
Solution Approach 1:
The curing agent is segmented into two functional parts: a dicyanamide salt component that provides latent curing capability at ambient temperature, and a separate curing accelerator component that activates the reaction only when needed. This segmentation allows the composition to remain stable during storage while enabling curability when applied.
Solution Approach 2:
The dicyanamide salt is prepared in advance as a stable latent curing agent that does not react immediately upon mixing with epoxy resin. The curing reaction is preliminarily inhibited until the addition of the curing accelerator, which then triggers the curing process. This preliminary action extends the pot life significantly.
2Stability of the object's composition
If a latent curing agent like dicyandiamide or melamine is used, then storage stability is excellent, but high temperature (150°C or higher) and long time are needed to cure
Solution Approach 1:
A curing accelerator acts as an intermediary substance that mediates between the stable dicyanamide salt and the epoxy resin. The accelerator triggers and accelerates the curing reaction of the dicyanamide salt at much lower temperatures (ambient to 80°C) than would otherwise be required, while the dicyanamide salt maintains its excellent storage stability.
3Productivity
If a curing accelerator is added to shorten curing time, then curability is improved, but storage stability is remarkably reduced
Solution Approach 1:
The system transitions from a static stable state (dicyanamide salt + epoxy resin with excellent storage stability) to a dynamic reactive state upon addition of the curing accelerator. The curing accelerator is added only when needed, dynamically controlling the timing of the curing reaction to achieve both long storage stability and fast curing when applied.
Solution Approach 2:
The dicyanamide salt is prepared in advance as a stable latent curing agent. The curing accelerator is added as a preliminary action only when the composition is ready for application, triggering the curing reaction at the optimal moment. This preliminary addition strategy maintains storage stability during storage while enabling fast curing when needed.
4Ease of operation
If a one-pack type epoxy resin composition is developed, then ease of application is improved, but either storage stability deteriorates or high temperature curing is required
Solution Approach 1:
The one-pack composition segments the curing system into a latent dicyanamide salt component and a curing accelerator component that are pre-mixed but remain chemically inert to each other during storage. This segmentation allows the composition to be stored as a single pack with excellent stability while maintaining the capability to cure at ambient temperature when applied.
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 dicyanamide salt-based epoxy resin composition achieves a balance of moderate curing characteristics and storage stability, enabling easy application to hard-to-reach places and maintaining workability, while avoiding the need for additional curing agents at high temperatures.
Implementation Method 1
a curing agent that does not react at room temperature but commences reaction to cure upon heating
Data Source
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AI summary
An epoxy resin composition excellent in storage stability and curability is provided. Particularly, a compound of general formula (I) and an epoxy resin composition containing the compound as a curing agent are provided. In formula (I), R1 is a hydrocarbon group optionally containing a nitrogen atom and capable of forming a cyclic structure optionally having a substituent; R2 is a hydrogen atom, an alkyl group, or an aryl group or is taken together with R1 to form an unsaturated bond; R3 is a hydrogen atom, an alkyl group, or an aryl group; and X is a dicyanamide ion or a thiocyanate ion.