The powder coating has a tendency to agglomerate at a certain temperature, which is mainly caused by the resin, leveling agent and other materials in the powder coating being softened by heat, and it is also the physical property of the micronized substance.
Resin has a physical property.
At lower temperatures, it appears as a hard and brittle glass state.
When the temperature rises to a certain level, the resin begins to transform into a state with a certain degree of elasticity and adhesion, below this temperature.
, The resin returns to the non-adhesive glass state, the temperature at which the glass state and the viscoelastic state of the resin transition mutually is called the glass transition temperature of the resin.
Powder coating formulations The larger the amount of added material having a low glass transition temperature, the glass transition temperature of the system, the lower com" href="">coating line coatingol.
During production, the glass transition temperature of the powder system is positioned at about 40 degrees Celsius, and this temperature is set as the safe temperature for powder coating agglomeration.
Then in production (and during product storage and transportation), use this as a standard, and relevant personnel should strengthen the random inspection of product agglomeration when the temperature is close to and above this temperature.
Entering the summer production stage, the rise in temperature will make it easier for powder coating products to agglomerate.
So how to prevent the agglomeration of powder coatings during work?
1) When selecting resins, select some resins with high glass transition temperature (Tg).
2) Reduce the use of low glass transition temperature polymers in powder coating formulation design or use good quality products, such as brighteners and matting agents, which can be used as little as possible to ensure that the glass transition temperature of the powder coating system will not decrease .
3) In terms of production, the crushed flakes from the extruded sheeting steel belt should be fully cooled before entering the grinding process.
4) When grinding powder, the feed speed should be appropriately reduced, the induced air volume should be increased, and the inlet air should be equipped with air-conditioning to control the temperature of the grinding powder.
5) Anti-caking additives, such as nano-silica or alumina C, can be added to prevent adhesion between powder particles.
Anti-caking agents generally have the best grinding effect with crushed flakes at the same time.
6) Control the storage temperature and humidity in the workshop to avoid moisture absorption and moisture absorption of the powder.
7) Control the temperature and humidity of the workshop and the cooling water temperature of the extrusion tablet press to prevent condensation of water droplets, causing water in the tablet material.
8) Improve the air inlet of the mill and leave some gaps to prevent insufficient air inlet.
9) Agglomeration of powder when heated is a physical phenomenon caused by normal molecular thermal movement.
The powder should be stored in a dark, dry space (recommended to be stored in an air-conditioned warehouse)
10) It also needs attention during transportation.
Air-conditioned vehicles and trucks with shade cloth should be used instead of box trucks.
Xifa Chaozhi is the ideal time for transportation.
11) Remember not to stack them next to the drying tunnel.
The fluidized bucket of slight powder mass can be solved by airflow.
Soybean particles need to be sieved.
Large ones need to be returned to the factory for reprocessing and used after the experiment.