The main factors affecting the curing of paint
Factors affecting the curing speed are the main types of paint, coating thickness, curing methods, curing conditions, curing equipment and specific curing procedures. 1.The type of paint Under the same curing conditions, the type of paint is different, the curing speed is very different. Generally speaking, the volatile paint curing fast, oily paint curing is slow. Polymeric paint is very different. Polymeric paint in the light-cured paint the fastest curing, and other polymer-based paint is more than between the volatile paint and oily paint. When use mechanized lines for finishing, the volatile paint, acid-cured amino acid alkyd paint is more commonly used. 2.Coating thickness In the coating process, the coating is basically not formed once, usually using many times thin coating method (such as oil paint generally coated about 35μm, nitro paint 15μm, etc.). Under the same curing conditions, the thin coating in the curing, the internal stress is small, the formation of less coating defects; and the coating is too thick, the internal stress is large, easy to produce wrinkles and other defects, and because of solvent evaporation , Coating shrinkage, resulting in uneven gloss, the internal non-curing and so on. Practice has proved that, in addition to polyester paint, the other paint through the formation of multiple paint film, and a coating formed by the same thickness of the film compared to its physical properties is better. 3.Curing conditions 1)The curing temperature plays a decisive role in the curing rate of most coating coatings. When the curing temperature is too low, the solvent evaporation and chemical reaction is slow, the coating is difficult to cure. Improve the temperature, can accelerate the evaporation of solvents and water evaporation, accelerated coating oxidation and thermal chemical reaction, coating curing speed. It cannot increase the temperature indefinitely, because the temperature and curing speed is not directly proportional relationship. Curing temperature is too high, the curing speed is not significantly improved, but will make the film yellow or darker color. Not only that, the temperature in the coating curing process also has an impact on the substrate. Such as substrate heat, causing moisture content changes, the substrate shrinkage deformation, and even warping, cracking. Volatile paint coating, curing temperature exceeds 60 ℃, the solvent is volatile, the surface quickly dry, the internal solvent vapor to reach the surface when prone to bubbles. Therefore, the use of artificial curing method, the surface temperature is generally not more than 60 ℃. 2)Air humidity should be appropriate The temperature is too high, the evaporation rate of the water in the coating decreases, the solvent evaporation rate slows down, which will slow down the curing speed of the coating. Most of the coating in the relative humidity of 45% to 60% of the air curing is most suitable. If the drying and curing sites are ...
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