This document discusses PVC compounding and provides details on the various ingredients that can be added to PVC to modify its properties. It describes the key ingredients used which include stabilizers to prevent degradation, lubricants to reduce friction during processing, plasticizers to make PVC flexible, fillers to reduce costs and modify properties, pigments to add color, flame retardants for fire resistance, and blowing agents for foaming. The document provides examples of specific materials used for each ingredient type and discusses their effects and applications in PVC products.