Classifications of the Use of Curing Agents

Curing agent is also known as hardener, maturing agent or variable set agent. The curing agent definition is a substance or mixture that enhances or controls the curing reaction. Resin curing is a process that makes the thermoset resin irreversibly change through the chemical reaction of condensation, closed-loop, addition or catalysis. The curing is accomplished by adding a curing (crosslinking) agent.

Curing agents can be classified by chemical composition: 1. Aliphatic amines, such as vinyltriamine, DETA, AminoethylpiperazineAE 2. Aromatic amines such as m-phenylenediamine, m-PDA, MPD, diaminodiphenylmethaneDDM, HT-972, DEH-50 3. Amide-based amines 4. Latent-curing amines 5. Urea substitutes.

The curing agent can be divided into room-temperature curing agents and heating curing agents by use. Epoxy resins generally perform well when cured at high temperatures. However, substances such as paints and adhesives used in civil construction need be cured at room temperature due to heating difficulties. This is why most curing agents used are fatty amines, alicyclic reflections and polyamides, especially in winter when paints and adhesives have to be combined with polyisocyanates, or polyurethanes with a foul odor.

As for choosing medium-temperature curing agents and high-temperature curing agents, it is based on the heat resistance of the applied body and the heat resistance, adhesion, and chemical resistance of the cured products, focusing on polyamines and anhydrides. Because of its excellent electrical properties, the anhydride curing material is widely used in electronics and electrical appliances.

Aliphatic polyamines have excellent adhesion and resistance to both alkali and water. Also, aromatic polyamines are excellent in drug resistance. Because the nitrogen element of the amino acid forms a hydrogen bond with the metal, it has outstanding anti-rust effect. The higher the concentration of amine is, the better the anti-rust effect will be. Acid anhydride curing agents and epoxy resins can form ester bonds, which shows high resistance to organic acids and inorganic acids. Generally, its electrical performance also exceeds that of polyamines.