It is a natural law for powder coatings to agglomerate at a certain temperature. To prevent powder coating from agglomerating, it is necessary that the powder coating product is below its glass transition temperature during the whole process of powder coating production, such as grinding, packaging, storage, and transportation.
There are workarounds as follows:
1) In the production of polyester resin, select some alcohols or acids that can increase the glass transition temperature, or reduce the amount of alcohol that can lower the glass transition temperature of the resin to increase the glass transition temperature of the polyester resin.
2) Reduce the use of low glass transition temperature polymers in the formulation design of powder coatings, such as leveling agents and brighteners, so as to ensure that the glass transition temperature of the powder coating system will not decrease.
3) In terms of production, the broken pieces on and off the steel belt should be fully cooled before entering the milling process. During milling, the feeding speed should be appropriately reduced, the air volume of the induced air should be increased, and the imported air should be equipped with a cooling air conditioner to control the milling process. temperature. However, if the crushed flakes cannot be cooled down before grinding, the latter means will not play a very good role. The method of forced cooling of the crushed flakes can be considered for low-temperature treatment, which is more effective than adding an air conditioner.
In addition, anti-caking additives can be added, such as nano-silica (VK-SP15) or nano-alumina (VK-L20M) powder to prevent adhesion between powder particles. Anti-caking agents are generally mixed with broken tablets at the same time. The grinding effect is better.
