What is epoxy resin curing agent?

Epoxy resin curing agent: Epoxy resin curing agent reacts chemically with epoxy resin to form a three-dimensional network polymer.The realization of the excellent performance of epoxy resin depends on the curing agent. As an indispensable component of the epoxy system, the curing agent largely determines the structure and physical and chemical properties of the cured product.

Epoxy resin curing agents are generally divided into two categories: alkaline curing agents and acidic curing agents.In the research and application of epoxy resin curing agents, the most widely used are amine curing agents, among which aromatic amine curing agents, alicyclic amine curing agents and fatty amine curing agents are the main ones.

 Alicyclic amine curing agent contains alicyclic rings in its molecules, which gives it better heat resistance and mechanical properties. It also has the advantages of light color, high gloss and excellent UV resistance.Due to the presence of alicyclic rings, their reactivity is lower than that of fatty amines and their pot life is longer. However, at the same time, some alicyclic amine curing agents are difficult toclassification

The molecular structure of aromatic amine curing agents contains a stable benzene ring structure. Due to the presence of the benzene ring, the cured product has high heat resistance and good water resistance, electrical properties and mechanical properties. Therefore, aromatic amine curing agents have great application prospects in the aerospace materials and insulation materials industries.At the same time, aromatic amine curing agents also have obvious disadvantages. Since the amine group is directly connected to the benzene ring, the main obstacle of the benzene ring leads to a low curing and cross-linking reaction activity. In addition, their melting points are generally high, so high temperature curing is required, so there are limitations in their application.In addition, aromatic amine curing agents have disadvantages such as high toxicity and easy oxidation by air.Fully react at room temperature and need to be heated to fully cure.Isophorone diamine is a commonly used alicyclic amine curing agent, mainly used in epoxy formulations requiring low color, low odor, high flexural strength and chemical resistance, suitable for floor coatings, paving fillers and mixtures.

Fatty amine curing agents mainly include ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, etc.This type of curing agent can fully react with epoxy resin to undergo curing and cross-linking reaction at room Fatty amine curing agents temperature or lower temperature, and the cured product has good corrosion resistance, water resistance, mechanical strength and bonding performance.However, most fatty amine curing agents are low molecular weight linear molecules, they have high vapor pressure, strong irritation, high toxicity, strict matching ratios, and high requirements for operators. These shortcomings limit their application.In order to improve the obvious shortcomings of fatty amine curing agents, low molecular weight primary fatty amines are used as raw materials and amine adducts are obtained through certain chemical modifications. The odor of the primary fatty amines is improved and the ratio requirements are reduced, thereby greatly broadening its application range.