Detailed recommendation

Detailed recommendation:

Process: Recommendations Description
Preparation
of the
lacquer
suspension
Container, tank for slurry preparation.

 

The container should be selected to the required amount of lacquer. The volume of lacquer in the tank should be between 60% and 75% of the tank’s total volume. The tank should be slim (higher than wider). Keep in mind that there should be another container to which we will pour the lacquer through the sieve before coating process.
Stirrer: size and rotation

 

The type of stirrer is not important, practically we choose the stirrer so that it does not create excessive foam in the lacquer, which is a disadvantage. It is best to use a paddle stirrer. The stirrer should be immersed in the lacquer from 5 to 15 cm from the bottom of the container or tank. The speed of the stirrer should be adjusted in such a way to make the funnel, about 4-10 cm deep.
Recommended slurry concentrations based on dry content

 

The concentration of the dry shell mixture should be selected according to your coating equipment, in particular, the diameter of the spray gun nozzle. The larger the diameter of the nozzles, the lacquer should have a higher viscosity, it should contain a higher concentration of the dry shell mixture. Recommended dry mixture concentration in the lacquer is from 15% to 25%.
Water temperature:

 

Purified water from 18 ° C to 40 ° C should be used to dissolve the dry shell mixture.
Method of dissolving the dry shell mixture: The dry shell mixture should be poured into purified water, continuously in small portions, to prevent the formation of large glued agglomerates. After pouring the whole dry shell mixture, mix the lacquer for about 2 hours. The lacquer should be stored in a clean tank with a stirrer. The stirrer should be switched on to minimum revolutions or switched on periodically.
Finished lacquer filtration: There is no need to sieve the lacquer if the lacquer was mixed for 2 hours. When it is necessary to apply the lacquer earlier than two hours, the finished lacquer should be poured through a sieve of 0.4 mm, to get rid of solid residue, this prevents clogging of the gun nozzle during the coating process.
Coating
process
Tablet cores preparation for the process

 

Most tablets should be heated to 35 ° C in a barrel. The tablets should not be rolled in the deposit during the preheating process, f possible periodically mix the tablets deposit using the lowest barrel speed.
Coating process parameters
Preliminary Step:
The spray air pressure depends on the use of appropriate gun nozzles, should be between 2.2 and 3.2 bar. Before the process, the spray and cone shape of spray lacquer should be checked, preferably outside the coating machine. After starting the process use vaccum in the barrel to prevent excessive dusting. Drying air should be set to provide adequate drying – airflow depends on the size of the deposit and the number of guns. Recommended drying air temperature: 40 – 45 ° C. It is best to apply low revolutions at the beginning. . The preliminary step (at low barrel rotation) leads to a 1% increase in tablet weight calculated on the tablet cores.
  Coating process parameters
Main stage:
Spray air pressure unchanged. Drying air temperature unchanged. It is recommended to increase the speed of barrel and lacquer dosing rate. The process should lead to achieve from 3% to 4% weight gain of tablet calculated on tablet cores.
End of
coating
Parameters of the drying and cooling process Dry the tablets with air at a temperature of about 20-25 °C. It is recommended to set the minimum values of the barrel rotation. Process should be run for maximum 20 minutes.
Tablets seasoning After unloading from the barrel, the tablets should be left for at least 2 hours in open containers to achieve the balance of tablets surface humidity with environment humidity.