Polyvinyl chloride (PVC) is actually a versatile and resource efficient thermoplastic together with the widest range of uses of some of the plastics family making it beneficial in nearly all regions of human activity.
Without additives pvc compound would not be an especially useful substance, but its compatibility with a wide range of additives – to soften it, colour it, ensure it is more processable or longer lasting, produces a wide range of potential applications from car underbody seals and flexible roof membranes to pipes and window profiles. PVC products might be rigid or flexible, opaque or transparent, coloured and insulating or conducting. There is not just one PVC but a huge group of products tailor-created to suit the needs of each application. Unlike most other thermoplastics, nearly all PVC applications have got a lifetime which is between 10 and 100 years. This calls for proven durability and stabilisers play an essential part in achieving such performance. All polymers require stabilisers of just one sort or other; PVC is not any different in this way.
Before PVC can be made into products, it should be combined with a selection of special additives. The essential additives for all PVC materials are stabilisers and lubricants; in the case of rigid pvc compound, plasticisers can also be incorporated. Other additives which may be used include fillers, processing aids, impact modifiers and pigments. Additives pvcppellet influence or determine the mechanical properties, light and thermal stability, colour, clarity and electrical properties in the product. As soon as the additives happen to be selected, they are combined with the polymer within a process called compounding. One method uses an intensive high-speed mixer that intimately blends all the ingredients. The effect can be a powder, known as a ‘dry blend’, which can be then fed in to the processing equipment.
The second technique is to blend the constituents either in a low or high-speed mixer then transfer the powder to your melt compounder. This will either be a compounding extruder, or another special equipment for creating pvc compound. These create a melt which, when cool, is cut into granules ready for processing. In the specialised process, liquid compounds known as plastisols, are made as dispersions of very fine PVC polymer particles in liquid organic media. PVC compounds are manufactured into products using many different processing methods such as extrusion, injection moulding, blow moulding, calendering, spreading and coating.