Although Compounding is extrusion, it is a unique enough subset of extrusion to merit its own discussion. Compounding involves the addition of resins, fillers, stabilizers, reinforcements, and or colorants to a base resin. What separates standard profile or film extrusion from compounding is the amount of additives introduced to the base resin – this is where compounders add their value. A typical compounding line will have multiple ports where additives are introduced to the melt. These ports are areas of low melt pressure, and are often difficult for purging compounds to clean. Because of these differences and challenges, compounding is an area that is currently under-served by commercial purging compounds. Following are some reasons to consider purging compounds in Compounding applications, as well as some tips to get the most out of your purge.
The main applications for compounding include: