Fast Curing Epoxy Systems via Strong Acid Catalyst
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Solution Overview
Problem
Existing epoxy resin systems cure too slowly, especially at temperatures below room temperature, which hinders productivity and is problematic for applications like corrosion protection in cold environments.
Innovation Solution
Compositions comprising at least one epoxy resin, a cyclic amine of specific formula, and a salt of a very strong Brönstedt acid with a pKa value ≤ -9.01, which accelerates curing by optimizing the epoxy to amine ratio and using a strong acid catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional epoxy resin systems are used, then good chemical and solvent resistance is achieved, but curing occurs too slowly especially at temperatures below room temperature
Solution Approach 1:
The patent applies parameter changes by introducing a salt of a very strong Brönstedt acid (pKa ≤ -9.01) as a catalyst to fundamentally alter the curing kinetics of the epoxy-amine system. This catalyst dramatically increases the reaction rate at low temperatures, enabling surface hardening within minutes and complete hardening at temperatures well below room temperature, thus resolving the contradiction between maintaining chemical resistance and achieving fast curing.
Solution Approach 2:
The salt of a very strong Brönstedt acid acts as an intermediary catalyst that mediates between the epoxy resin and cyclic amine, facilitating the curing reaction at low temperatures. This intermediary substance enables the reaction to proceed rapidly without requiring high temperature input, thereby solving the time loss issue while maintaining the desired chemical properties of the cured system.
2Speed
If high temperatures are used to accelerate curing, then curing speed increases, but applications in cold areas become problematic
Solution Approach 1:
The patent changes the temperature parameter by using a strong acid catalyst that enables the curing reaction to proceed rapidly at temperatures well below room temperature. This eliminates the need for high temperature processing, making the system suitable for applications in cold areas while maintaining fast curing speeds.
Solution Approach 2:
The salt of a very strong Brönstedt acid serves as a catalyst intermediary that allows the curing reaction to occur at low temperatures by providing an alternative reaction pathway with lower activation energy, thus resolving the contradiction between curing speed and temperature requirement.
3Strength
If the epoxy to amine ratio is optimized, then crosslinking density and mechanical properties increase, but unreacted components may remain causing side reactions
Solution Approach 1:
The patent optimizes the epoxy to amine ratio parameter to achieve complete reaction conversion. By carefully controlling this stoichiometric ratio and using a highly effective catalyst, the system achieves full crosslinking density without leaving unreacted components, thereby simultaneously improving mechanical properties and eliminating sources of side reactions.
Solution Approach 2:
The patent employs feedback control in the form of a highly effective catalyst system that ensures complete reaction progression. The catalyst promotes thorough reaction until all reactive groups are consumed, providing a self-regulating system that achieves optimal crosslinking without excess unreacted components that could cause reliability issues.
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 compositions cure significantly faster than conventional systems, achieving quick surface hardening and complete hardening at low temperatures, enhancing mechanical properties, chemical resistance, and scratch resistance without leaving unreacted components that could cause side reactions.
Implementation Method 1
a salt of a very strong Brönstedt acid with a pKa value ≤ -9.01, which accelerates curing
Data Source
AI summary
The present invention relates to a composition comprising a) at least one epoxy resin, b) at least one cyclic amine of formula (I) in which - R1 to R4 represents H or organic residue and - X = -(Y1)m-(A1)n-(Y2)o-(A2)p-(Y3)q-(A3)r-(Y4)s-, (II) wherein independently of one another - m, n, o, p, q, r and s = 0 or 1, - A1, A2, A3 = alkylene or alkenylene residue and - Y1, Y2, Y3, Y4 = NR5, PR5, O or S, wherein independently of one another = organic residue, - wherein any two organic residues selected from R1 to R5 and any alkylene and/or alkenylene residues A1, A2, A3 present may also form one or more further rings, - provided that at least one of the existing residues is selected from R1 to R5 and possiblyc) at least one of the alkylene and/or alkenylene residues A1, A2, A3 present is substituted with at least one group -NHR6 or -NH2, where R6 = organic residue, and c) at least one salt of a very strong Brønsted acid with a counterion selected from metal ions, metal-containing ions, phosphonium ions and unsubstituted ammonium ions, process for its preparation and its use.