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What factors affect the curing of coatings?

Sep 21, 2019

The main factors affecting curing speed are coating type, coating thickness, curing method, curing condition and external factors.

1. Paint type.
Under the same curing conditions, the curing speed is very different with different types of coatings. The curing rate of the coating is determined by the properties of the film-forming material, which is different from the wax-forming material of the coating. For example, the curing speed of photosensitive paint is faster, while other polymerized paints are mostly between volatile paint and oily paint. When the mechanized assembly line is used for finishing, volatile paint and acid-cured amino alkyd paint are more commonly used.
2. Coating thickness.
In the process of coating construction, the coating is basically not formed at one time, and the method of thin coating is usually used many times (such as oily paint about 35 μ m at a time, nitro paint about 15 μ m, etc.).
Under the same curing conditions, when the thin coating is cured, the internal stress is small and the defects of the coating are less. When the coating is too thick, the internal stress is large, easy to wrinkle and other defects, at the same time, due to solvent volatilization, coating shrinkage, resulting in uneven gloss, there will be internal non-curing and so on.
3. Curing conditions.
1) curing temperature.
Curing temperature has a decisive effect on the curing rate of most coatings.
When the curing temperature is too low, the solvent volatilization and chemical reaction are slow, and the coating is difficult to solidify. Increasing the temperature can accelerate the solvent volatilization and water evaporation, accelerate the oxidation reaction and thermochemical reaction of the coating, and accelerate the curing speed of the coating. However, the temperature can not be increased indefinitely, because the temperature is not proportional to the curing rate. When the curing temperature is too high, the curing speed does not increase obviously, but will ma