1. Advantages of powder coating
Powder coatings do not use organic solvents in the preparation and coating process, so they have certain advantages in terms of ecological environmental protection, economy and process characteristics, specifically as follows:
①The powder coating does not contain volatile organic compounds (VOC), which not only avoids the problems of fire, poisoning and unsafe transportation caused by organic solvents , but also avoids environmental pollution and will not cause harm to people and the environment , does not produce the three wastes problem.
②Because the powder coating is a 100% solid system, it can be , which will not cause overspray during spraying (the sprayed powder can also be recycled and used), so the loss of the coating during coating is small, and the coating is durable. The utilization rate can reach more than 90%.
③The thickness of the coating film is easy to control. The thickness of the coating film in one coating is relatively thick and can be controlled within 30~500μm, which is equivalent to the thickness achieved by several or even dozens of coatings of solvent-based coatings. Therefore, the production process can be simplified and the construction efficiency can be improved. , saving energy and labor.
④ The relative molecular mass of the film-forming substance in powder coatings is larger than that in solvent-based coatings, so the performance and durability of the formed coating film are better than those of solvent-based coatings, and the coating film has excellent physical and mechanical properties (such as not easy to be scratched) , impact resistance, strong and durable, with excellent chemical resistance, etc.).
⑤ During the construction process, it is not necessary to adjust the viscosity of the paint with seasonal changes, and the construction operation is also very convenient. It does not require skilled operation techniques. It has good coating performance on the corners of the workpiece, and it is not easy to cause problems such as sagging when thick coating, so Easy to implement automated assembly line production.
⑥ good security. Because the powder coating is odorless, non-toxic, does not contain heavy metals, and has no adverse effects on the human body , it is relatively safe to produce and operate. Although improper handling of fine powder of powder coatings can cause explosions, as long as the dust concentration in the system is properly controlled, explosions can be completely avoided.
2. Disadvantages of powder coating
Powder coatings have been developed for more than half a century, but as a new energy-saving, energy-saving, and pollution-free coating, compared with water-based coatings and high-solid content coatings, its development speed is far slower than the other two coatings. This is related to the following disadvantages and problems of powder coatings.
① The requirements for the equipment for manufacturing powder coatings are relatively high, so the required investment is relatively large. For example, dry mixing of various components in powder coatings will cause component separation due to different material densities, so it needs to be mixed in the molten state of the resin, so the expensive melt mixing extruder is a necessary equipment .
② The color matching of powder coatings is difficult, and it is troublesome to change the color and variety of coatings during coating , and the cost is high.
③ Powder coating needs to use unique process equipment, so the replacement of coating equipment requires a large investment.
④ The coating film curing of powder coatings generally still needs to be carried out , which does not meet the requirements of energy saving, and also limits its use on substrates such as plastics, wood, and paper with poor heat resistance .
⑤The coating of powder coating is relatively thick, so it is not suitable for use in the case of thin coating.
⑥Powder coating is greatly affected by pressure, temperature and humidity during storage, and it is easy to agglomerate.
