Mixed Adduct Amine Curing Agent for Low-Emission Epoxy Resins
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Solution Overview
Problem
Epoxy resin coatings face challenges in achieving low viscosity, rapid curing at ambient and cold temperatures, and high-quality, shiny surfaces without defects or yellowing, especially under moist and cold conditions, using existing curing agents like cycloaliphatic diamines and their adducts.
Innovation Solution
A mixed adduct amine curing agent is developed from a mixture of primary diamine and partly alkylated diamine with polyepoxide, which enables low-odor, low-emission epoxy resin products with reduced viscosity and improved surface quality, curing speed, and resistance to yellowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If cycloaliphatic diamines (e.g., IPDA) are used as curing agents and converted to adducts, then the epoxy resin products have low emissions and good surface quality, but the viscosity becomes undesirably high and the surface quality deteriorates under moist and cold conditions
Solution Approach 1:
The patent combines two different diamines (a cycloaliphatic diamine and a partly alkylated primary diamine) into a mixed adduct formulation. This merging allows the composition to benefit from the low emission properties of the cycloaliphatic diamine while the partly alkylated primary diamine contributes to lower viscosity and better surface quality under moist and cold conditions, resolving the contradiction between emissions and viscosity/stability
Solution Approach 2:
The invention creates a composite curing agent system by forming adducts from a mixture of two different diamines with epoxy resin. This composite approach allows the final product to exhibit properties that neither component alone could achieve, specifically maintaining low emissions while achieving acceptable viscosity and surface quality under challenging conditions
2Object-generated harmful factors
If cycloaliphatic diamines (e.g., IPDA) are used as curing agents and converted to adducts, then the epoxy resin products have low emissions, but the surface quality deteriorates with matt surfaces and white spots under moist and cold conditions
Solution Approach 1:
The patent merges two diamine types in a mixed adduct formulation where the cycloaliphatic diamine provides low emissions while the partly alkylated primary diamine prevents surface defects. This combination resolves the contradiction by allowing both low emissions and high surface quality under moist and cold conditions to coexist
Solution Approach 2:
The invention changes the chemical composition parameters of the curing agent by introducing a partly alkylated primary diamine with specific structural characteristics (alkyl groups that reduce polarity). This parameter change in the curing agent composition prevents the formation of matt surfaces and white spots while maintaining low emissions
3Stability of the object's composition
If diamines such as MXDA are used in adduct formation to reduce viscosity, then the viscosity decreases, but the tendency to yellowing under light increases and surface quality worsens under moist and cold conditions
Solution Approach 1:
The patent combines a cycloaliphatic diamine (which has low yellowing tendency) with a partly alkylated primary diamine in a mixed adduct formulation. This merging allows the system to achieve low viscosity from the partly alkylated primary diamine while the cycloaliphatic diamine component suppresses yellowing and improves surface quality, resolving the contradiction between viscosity and yellowing/surface quality
4Object-generated harmful factors
If partly alkylated primary diamines are used in free form, then low-emission epoxy resin products with good properties are achieved, but the curing speed and final hardness are often insufficiently high
Solution Approach 1:
The patent merges a partly alkylated primary diamine (which provides low emissions and good surface quality) with a cycloaliphatic diamine (which contributes to faster curing and higher hardness). This combination resolves the contradiction by allowing the system to maintain low emissions while achieving sufficiently high curing speed and final hardness through the synergistic effect of both diamine types
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 solution provides epoxy resin products with low viscosity, rapid curing, high hardness, and a shiny, even surface, even under challenging conditions, while minimizing the tendency to yellow, thus addressing the limitations of prior art.
Implementation Method 1
The curing agent comprises at least one mixed adduct amine of the formula (I) that can be obtained from adduct formation from a mixture of primary diamine and a partly alkylated further diamine with a polyepoxide
Data Source
AI summary
A curing agent for epoxy resins, containing at least one amine adduct of formula (I) which can be obtained as an addition product of a mixture of a primary diamine, a monoalkylated other diamine and a polyepoxide. The curing agent makes it possible to produce low-odor, low-emission epoxy resin products, in particular coatings, which have a surprisingly low viscosity, a high curing rate, a high final hardness, and a surprisingly appealing surface.