Epoxy Resin Composition Catalyst for Rapid Low-Temperature Curing
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Solution Overview
Problem
Heat-curing epoxy resin compositions face challenges with brittleness, leading to cracking under impact, and require rapid curing at lower temperatures while maintaining storage stability, which is difficult to achieve with existing accelerators.
Innovation Solution
A one-component thermosetting epoxy resin composition comprising an epoxy resin with multiple epoxy groups, dicyandiamide, and a specific accelerator derived from an amine/epoxy adduct, along with a toughness improver, which allows for rapid curing at 130-140°C while maintaining storage stability and impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aromatic ureas are used as accelerators to increase reactivity for rapid curing, then curing speed is improved, but storage stability deteriorates significantly
Solution Approach 1:
The patent changes the chemical structure parameters of the accelerator from conventional aromatic ureas to cyclic carbonic acid amine derivatives with specific molecular weight ranges (100-500 g/mol). This parameter change enables rapid curing at lower temperatures while maintaining storage stability, as the cyclic structure provides controlled reactivity compared to the highly reactive aromatic urea structures.
Solution Approach 2:
The patent introduces a specific local chemical structure feature - the cyclic carbonic acid amine derivative structure with defined molecular weight - into the accelerator component. This local structural quality provides the desired balance between reactivity and stability, where the cyclic structure enables controlled reaction kinetics that prevent premature curing while allowing rapid curing when activated.
2Temperature
If conventional accelerators are used to achieve rapid curing at lower temperatures, then curing temperature is reduced, but storage stability is compromised
Solution Approach 1:
The patent changes the physical and chemical parameters of the accelerator by selecting cyclic carbonic acid amine derivatives with specific molecular weights (100-500 g/mol). This parameter selection enables the system to cure at lower temperatures (100-150°C) while the cyclic structure maintains storage stability by providing controlled reactivity that prevents premature reaction during storage.
3Loss of time
If epoxy resin composition is designed for rapid curing, then curing time is reduced, but brittleness increases leading to cracking under impact
Solution Approach 1:
The patent creates a composite accelerator system combining cyclic carbonic acid amine derivatives with dicyandiamide and optional secondary accelerators. This composite approach balances the rapid curing effect with improved toughness, as the combination of different accelerator types provides both speed and resistance to brittleness in the cured epoxy resin 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 composition achieves rapid curing at lower temperatures, improves adhesion and impact resistance, and maintains storage stability, making it suitable for vehicle construction and structural foam production.
Implementation Method 1
at least one accelerator C, the accelerator C a compound obtainable by reacting: 1 part by weight of an amine/epoxy adduct (a) with 0.1 to 0.8, preferably 0.2 to 0.6, parts by weight of a compound (b) selected from the group consisting of phenolic resins and polyhydric phenolic compounds
Implementation Method 2
at least one epoxy resin A with on average more than one epoxide group per molecule
Data Source
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AI summary
The present invention relates to heat-curing epoxy resin compositions which exhibit a good storage stability and a low curing temperature. The epoxy resin compositions are particularly suitable for use as a structural adhesive and for producing structural foams.