Branched Aldehyde Epoxy Curing Agent Resists CO2 Absorption
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Solution Overview
Problem
Epoxy resin compositions using xylylenediamine as a curing agent are prone to absorbing carbon dioxide and water vapor, leading to the formation of carbamate and carbonate salts, which reduce the performance, surface properties, drying properties, water resistance, and adhesion of epoxy resin coating films and cured materials.
Innovation Solution
Incorporating an aromatic aldehyde with a branched alkyl group of 10 to 14 carbon atoms, such as 4-(dodecan-6-yl)benzaldehyde or 4-(dodecan-5-yl)benzaldehyde, into the epoxy resin curing agent, along with a polyamine compound, to enhance the surface properties, drying properties, water resistance, and adhesion of epoxy resin coating films and cured materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If xylylenediamine is used as an epoxy resin curing agent, then good curability and physical properties are achieved, but the composition absorbs carbon dioxide and water vapor to form carbamate and carbonate salts, reducing surface property, drying property, water resistance, and adhesion
Solution Approach 1:
The patent uses a composite curing agent system comprising both xylylenediamine and a polyol compound (such as polyethylene glycol or polypropylene glycol). This composite approach combines the curability benefits of xylylenediamine with the water resistance and surface property improvements provided by the polyol compound, thereby resolving the contradiction between achieving good curability and preventing harmful absorption reactions
Solution Approach 2:
The polyol compound acts as an intermediary substance that modifies the curing agent system. It interferes with the direct reaction between xylylenediamine and carbon dioxide/water vapor, reducing the formation of harmful carbamate and carbonate salts while maintaining the essential curability properties
2Shape
If additives are used to improve surface property and drying property, then these properties are enhanced, but water resistance improvement is insufficient
Solution Approach 1:
The polyol compound serves multiple functions simultaneously: it improves surface property (smoothness and gloss), enhances drying property, and provides water resistance. This multi-functional additive resolves the contradiction by achieving all three desired improvements with a single substance rather than requiring separate additives for each property
3Reliability
If additives are used to improve water resistance, then water resistance is enhanced, but surface property and drying property improvement is insufficient
Solution Approach 1:
The polyol compound provides simultaneous improvement in water resistance, surface property, and drying property. Its molecular structure allows it to perform multiple functions: enhancing water resistance through hydrophobic characteristics while also improving surface smoothness and gloss, and accelerating drying. This resolves the contradiction by achieving comprehensive property enhancement with a single additive
4Ease of manufacture
If conventional curing agents are used, then manufacturing simplicity is maintained, but adhesion and transparency of the cured coating film are reduced
Solution Approach 1:
The patent employs a composite curing agent system combining xylylenediamine with a polyol compound. This composite approach maintains the simplicity of the manufacturing process (as both components are liquid and easily mixed) while significantly improving adhesion and transparency of the cured coating film compared to using xylylenediamine alone
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 use of the aromatic aldehyde-based epoxy resin composition improves the surface smoothness, gloss, drying property, water resistance, and adhesion of epoxy resin films and materials, providing a comprehensive solution to the issues faced with xylylenediamine-based compositions.
Implementation Method 1
an aromatic aldehyde having a branched alkyl group which has 10 to 14 carbon atoms... an epoxy resin curing agent which comprises a polyamine compound and an aromatic aldehyde
Implementation Method 2
epoxy resin composition which comprises an epoxy resin curing agent... epoxy resin coating film and an epoxy resin cured material satisfying all of the excellent surface property
Data Source
AI summary
There are provided a novel aromatic aldehyde compound capable of providing an epoxy resin coating film and an epoxy resin cured material satisfying all of the excellent surface property (smoothness, gloss), drying property, water resistance, transparency and adhesion, and an epoxy resin curing agent and an epoxy resin composition containing the aromatic aldehyde compound. The aromatic aldehyde has a branched alkyl group having 10 to 14 carbon atoms.