Epoxy resin curing agent is an additive that reacts with epoxy resin to form a reticular three-dimensional polymer, envelops composite material in a reticular body, and makes the linear resin into a tough solid.
- classification
- Basic
Basic curing agent WTF: including aliphatic diamines, polyamines, aromatic polyamines, other nitrogen compounds and modified aliphatic amines.
- Acids
Acid curing agents: including organic acids, acid anhydride curing agent, boron trifluoride and its complexes.
- Addition type
Addition curing agent: this type of curing agent undergoes an addition reaction with an epoxy group to form a part of the segment of the cured product, and through a stepwise polymerization reaction, the linear molecules are cross-linked to form a body structure molecule. This type of curing agent is also called melon-type curing agent.
- Catalytic type
Catalytic curing agent: this kind of curing agent only initiates the epoxy resin. After opening the epoxy group, it catalyzes the polymerization of the epoxy resin into a network structure to form a homopolymer with an ether bond as the main structure.
- Explicit type
Explicit curing agent is a common curing agent, which can be divided into addition polymerization type and catalytic type. The so-called addition polymerization type is to open an epoxy ring to perform an addition polymerization reaction, and the curing agent itself participates in a three-dimensional network structure. If such kind of curing agent is added in a small amount, the cured product is connected to an unreacted epoxy group. Therefore, there is a suitable amount for this type of curing agent. Catalytic curing agents use cationic or anionic methods to ring-open addition polymerization of epoxy groups. In the end, curing agents do not participate in the network structure, so there is no suitable amount of equivalent reaction. However, increasing the amount will speed up the cure. Among the explicit curing agents, varieties such as dicyandiamide and adipic acid dihydrazide are insoluble in epoxy resin at room temperature, but begin to cure after dissolution at high temperature, so they also show a latent state. Therefore, it can be called a functional latent curing agent.
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