Polyvinyl chloride (PVC) can be a versatile and resource efficient thermoplastic together with the widest array of applications of any one of the plastics family which makes it useful in practically all parts of human activity.
Without additives pvc compound would stop being a particularly useful substance, nonetheless its compatibility with a wide range of additives – to soften it, colour it, help it become more processable or more durable, generates a broad 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 whole family of products tailor-designed to suit the requirements each application. Unlike many other thermoplastics, virtually all PVC applications have a lifetime of between 10 and 100 years. This calls for proven durability and stabilisers play an important part in achieving such performance. All polymers require stabilisers of one sort or some other; PVC is not any different in this respect.
Before PVC can be produced into products, it has to be coupled with a selection of special additives. The main additives for many PVC materials are stabilisers and lubricants; in the case of soft pvc granule, plasticisers will also be incorporated. Other additives which can 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 of your product. After the additives have already been selected, they are blended with the polymer in a process called compounding. One method uses an intensive high-speed mixer that intimately blends every one of the ingredients. The result can be a powder, known as the ‘dry blend’, which happens to be then fed in the processing equipment.
Another method is to blend the constituents in both a small or high-speed mixer after which transfer the powder to a melt compounder. This can either be a compounding extruder, or some other special equipment to make pvc compound. These generate a melt which, when cool, is cut into granules ready for processing. Within a specialised process, liquid compounds referred to as plastisols, are produced as dispersions of very fine PVC polymer particles in liquid organic media. PVC compounds are produced into products using a variety of processing methods including extrusion, injection moulding, blow moulding, calendering, spreading and coating.