Low-Emission Epoxy Hardener via Segmented Amine Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Epoxy resin coatings face challenges with high viscosity, slow curing, brittleness, and yellowing, especially under cold and moist conditions, and require high-emission solvents to achieve good processibility and surface quality, while existing hardeners based on Mannich bases have toxicity and odor issues.
Innovation Solution
A low-odor, low-toxicity, low-viscosity hardener for epoxy resins, comprising specific amines of formulas (I) and (II), which enable rapid curing and high-quality films with high gloss and hardness, reducing the need for solvents and minimizing blushing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Mannich bases are used as hardeners to achieve rapid curing and high strength, then the curing speed and final strength are improved, but the viscosity becomes too high for good processibility
Solution Approach 1:
The patent divides the hardener system into two distinct components: a low-viscosity amine component (formula I) that ensures good processibility and a high-reactivity amine component (formula II) that provides rapid curing. This segmentation allows each component to optimize its specific function without the drawbacks of high viscosity or slow curing when used alone.
Solution Approach 2:
The patent creates a composite hardener system by combining two different amine compounds with complementary properties. The first amine (formula I) contributes low viscosity and good flow characteristics, while the second amine (formula II) contributes high reactivity and rapid curing capability. The synergistic effect of this composite system resolves the contradiction between processibility and curing speed.
2Ease of operation
If low-molecular amines are added to reduce viscosity of Mannich bases, then the processibility is improved, but the odor level and toxicity increase significantly
Solution Approach 1:
The patent changes the molecular structure parameters of the amine components by selecting specific structural formulas (I and II) that inherently possess low viscosity without requiring small molecular weight. This structural parameter change allows the amines to maintain low viscosity for good processibility while avoiding the intense odor and high toxicity associated with low-molecular-weight amines.
3Manufacturing precision
If thinners are used to improve processibility and reduce blushing effects, then the surface quality is improved, but the emission level increases due to unreactive substances remaining after curing
Solution Approach 1:
The patent extracts and eliminates the need for unreactive thinners by using the amine hardener system itself to achieve the desired viscosity and surface quality. The reactive amine components cure completely to form part of the crosslinked network, leaving no unreactive substances that would cause emissions, while still providing good processibility and surface quality.
4Productivity
If Mannich bases are used to achieve rapid curing at low temperatures, then the curing speed is improved, but the yellowing tendency increases
Solution Approach 1:
The patent changes the chemical structure parameters of the hardener components by selecting specific amine structures (formulas I and II) that are less prone to oxidation and yellowing compared to traditional Mannich bases. These structural modifications maintain the rapid curing capability at low temperatures while significantly reducing the yellowing tendency in the cured coating.
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 hardener allows for epoxy resin products with low odor and emissions, excellent processibility, rapid curing at low temperatures, and high final hardness with minimal yellowing, even under unfavorable conditions, and reduces the occurrence of blushing-related defects.
Implementation Method 1
at least one amine of the formula (I)... which is very reactive toward epoxy resins
Implementation Method 2
at least one amine of the formula (II)... which is very reactive toward epoxy resins... cure rapidly even at low temperatures
Data Source
AI summary
A curing agent for epoxy resin compositions containing at least one amine of formula (I) and at least one amine of formula (II). The curing agent is a low-odor, low-viscosity, low-toxicity curing agent and has a low propensity for carbamatization and a high reactivity toward epoxy resins. It enables low-odor and low-emission epoxy resin products which are readily processable and which even at low temperatures and high humidities undergo rapid and problem-free curing to afford high-quality plastics having a high hardness and a regular, non-tacky surface with high gloss.