Low-Viscosity Epoxy Hardener via Amine Segmentation
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Solution Overview
Problem
Epoxy resin compositions for coatings face challenges in achieving low viscosity, rapid curing, and high hardness while minimizing blushing effects and odor, especially at low temperatures and high humidity, due to the use of highly viscous hardeners containing reaction products from polyamines and epoxides, which often require solvents or thinners that increase emissions and surface defects.
Innovation Solution
A low-viscosity hardener is developed using a specific amine of formula (I) and formula (II), which allows for quick curing and high hardness without solvents or thinners, maintaining low odor and preventing blushing effects, even at low temperatures and high humidity, by reacting with glycidyl ethers to form a hardener with a molecular weight suitable for easy processing and low emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If reaction products from polyamines with epoxides are used as hardeners, then rapid curing is achieved, but viscosity becomes very high
Solution Approach 1:
The hardener is segmented into two distinct components: a polyamine component and a glycidyl ether component. This segmentation allows each component to have optimized properties - the polyamine provides curing functionality while the glycidyl ether maintains low viscosity, resolving the contradiction between rapid curing and low viscosity.
Solution Approach 2:
The invention uses a composite hardener system combining polyamine and glycidyl ether components. This composite approach leverages the strengths of both materials - the reactivity of polyamines for rapid curing and the low viscosity of glycidyl ethers - achieving both fast curing and easy processing without the high viscosity of traditional adduct hardeners.
2Volume of stationary object
If non-adducted low molecular weight polyamines are used to reduce viscosity, then viscosity becomes manageable, but strong odor and blushing effects occur
Solution Approach 1:
The invention extracts and eliminates the harmful low molecular weight polyamine component from the hardener system. By using only the polyamine component in controlled reaction with glycidyl ether, the system removes the source of strong odor and blushing effects while maintaining appropriate viscosity through the glycidyl ether component.
Solution Approach 2:
The invention changes the molecular weight and chemical structure parameters of the hardener components. By using higher molecular weight polyamines in controlled reaction with glycidyl ethers, the system achieves appropriate viscosity without the harmful properties of low molecular weight polyamines, effectively changing the parameters to eliminate odor and blushing.
3Manufacturing precision
If thinners are used to reduce blushing effects and improve surface quality, then surface quality improves, but emissions increase and substances are released
Solution Approach 1:
The invention converts the previously harmful role of thinners into a beneficial integrated system. Instead of using separate thinner additives that cause emissions, the glycidyl ether component is chemically incorporated into the curing reaction, transforming from a potential emission source into an essential reactive component that improves surface quality without releasing substances.
Solution Approach 2:
The invention merges the functions of hardener and thinner into a single integrated hardener system. The glycidyl ether component simultaneously provides viscosity reduction (thinner function) and participates in the curing reaction (hardener function), eliminating the need for separate thinner additives and their associated emissions.
4Volume of stationary object
If low molecular weight polyamines are used, then viscosity is reduced, but blushing effects increase due to salt formation with CO2
Solution Approach 1:
The invention changes the molecular weight parameter of the polyamine component to higher values, which inherently reduces the tendency for blushing effects while maintaining manageable viscosity through the glycidyl ether component. This parameter change eliminates the root cause of blushing (salt formation) while achieving the desired viscosity.
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 enables epoxy resin compositions with low viscosity, rapid curing, high hardness, and minimal yellowing, forming beautiful, even surfaces without blushing or clouding, meeting eco-label standards and improving processing and safety properties.
Implementation Method 1
The amine of formula (I) contained in the hardener has a surprisingly low viscosity compared to other adduct amines and enables surprisingly rapid curing without causing blushing effects
Implementation Method 2
Epoxy resin compositions suitable for coating purposes should have the lowest possible viscosity so that they can be easily processed at ambient temperature. Furthermore, they should harden as quickly and smoothly as possible
Implementation Method 3
The non-adducted low molecular weight polyamines typically have a strong odor and lead to increased blushing effects
Data Source
AI summary
The present invention relates to 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 can be produced in a simple process from the reaction of a glycidyl ether with an excess of amine of formula (II), wherein the amine of formula (I) is obtained in higher purity. The curing agent has a surprisingly low viscosity, does not have a tendency for blushing and thins common epoxy resins very well. It enables low-emission epoxy resin coatings with the good workability, fast curing, greater hardness, attractive surfaces and less yellowing, which also cure quickly and without problems at low temperatures and high humidity.