Choice of Powder Coatings (2)

Choice of Powder Coatings (2)
2. The choice of curing agent
Curing agent is an important factor for resin modification and film formation, which directly affects the quality and film performance of powder coatings. Therefore, it is very important to choose a suitable curing agent, which should meet the following conditions:
(1) It is powder, granular or flake at room temperature.
(2) Chemical and physical stability: no chemical reaction with resin or other components during production or storage, and no agglomeration. When spraying, it can be cured quickly after baking to a given temperature, and the coating film is smooth, smooth and plump.
(3) The curing agent should be non-toxic (low toxicity) and non-irritating. It is better not to release peculiar smell and harmful odor during the baking process.
(4) The curing agent is colorless and cannot color the coating film and affect the appearance of the coating film.
3, the choice of pigment
Pigments and fillers in powder coating components cannot react chemically with other components during production, preparation and storage, and have better thermal and light stability. Pigments for powder coatings should meet the following conditions: can be uniformly dispersed in the resin, good thermal stability when the coating film is cured, good light stability, chemical resistance, solvent resistance, no bleeding, no frost in the coating film, no No migration, no color change due to other components, no aging of the resin, good dispersibility, good tinting strength and hiding power in the hot melt state of the resin.
Adding fillers to powder coating formulations also has a modification effect, such as adjusting the flatness, gloss and physical and mechanical properties of the coating film. The selection requirements for fillers are:
1. It is easy to disperse in the formulation components and has good fluidity.
2. Does not contain foreign matter and impurities that affect the quality of the coating film.
3. No harmful chemical reaction with other components.
4. Does not reduce the physical and mechanical properties of the coating film.