Classification and selection of curing agents

24-03-2020

The curing agent can be divided into normal temperature curing agent and heating curing agent according to the application. Epoxy resins generally have good properties when cured at high temperatures, but coatings and adhesives used in civil construction need to be cured at room temperature due to difficult heating; therefore, fatty amines, cycloaliphatics, and polyamides are mostly used, especially those used in winter. Coatings and adhesives have to be used in combination with polyisocyanates, or polyalcohols with an offensive odor.

The type of curing agent has a great impact on the mechanical properties, heat resistance, water resistance, and corrosion resistance of the cured product. For example, curing agents such as aromatic polyamines, imidazoles, and anhydrides have higher heat resistance than epoxy resins. Polyamine, low molecular weight polyamide curing agent; aromatic acid anhydride cured epoxy resin has better water resistance than aromatic diamine and aliphatic polyamine curing agent  curing agent has good alkali resistance, but acid resistance and resistance. Alicyclic polyamine cured epoxy resin has excellent resistance. The acid resistance of acid anhydride cured epoxy resin is better than acid resistance. The appropriate curing agent should be selected according to different applications and performance requirements.

Curing agent selection:

The curing agent has a great influence on the performance of epoxy resin. Generally, it is selected according to the following points:

(1) Select from performance requirements: some require high temperature resistance, some require good flexibility, and some require good corrosion resistance, then select an appropriate curing agent according to different requirements.

(2). Choose from curing methods: Some products cannot be heated, so you cannot use heat curing curing agents.

(3). Choose from the applicable period: The so-called period refers to the period from when the epoxy resin is added to the curing agent to when it cannot be used. To apply for a long period of time, acid anhydrides or latent curing agents are generally used.

(4) Choose from safety: Generally, it is better to have low toxicity, which is convenient for safe production.

(5) Choose from cost


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