Purging compounds are materials which are designed to clean the plastic processing machinery to ensure a smoother transition to another material or to prevent material inside the barrel from degradation. Broadly they are divided into two categories: Mechanical purges and Chemical purges.
Purging compounds which work by mechanical purging are designed specifically using a similar resin and primarily rely on the scrubbing action to clear the material stuck inside the extruder. These formulations are usually high viscosity compounds which work using the brute force of the machine to mechanically clean the contamination. However, if not formulated correctly they could lead to damaging the machine over prolonged periods. This kind of cleaning is usually used for regular maintenance
Purging compounds which work by chemical purging are designed to work by chemically reacting with the contamination, residual polymers, charred material etc. and breaking them down for easy removal from the processing equipment. Since these work by chemical reaction, chemical purges usually have a “soak time” of a few minutes which allows the reaction to take place. This type of purging is typically used for deep cleaning of the equipment.