Polyvinyl chloride (PVC) is a versatile and resource efficient thermoplastic with the widest selection of uses of some of the plastics family so that it is beneficial in practically all parts of human activity.
Without additives pvc compound would not an especially useful substance, nonetheless its compatibility with a wide array of additives – to soften it, colour it, make it more processable or longer lasting, generates a wide range of potential applications from car underbody seals and versatile roof membranes to pipes and window profiles. PVC products could be rigid or flexible, opaque or transparent, coloured and insulating or conducting. There is not just one PVC but an entire group of products tailor-intended to suit the requirements each application. Unlike the majority of thermoplastics, nearly all PVC applications have got 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 a single sort or other; PVC is not any different in this way.
Before PVC can be made into products, it needs to be along with an array of special additives. The essential additives for all those PVC materials are stabilisers and lubricants; in the case of rigid pvc compound, plasticisers are also incorporated. Other additives which is often 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 from the product. After the additives are already selected, they are combined with the polymer in a process called compounding. One method uses an intensive high-speed mixer that intimately blends each of the ingredients. The effect is a powder, known as the ‘dry blend’, which happens to be then fed in the processing equipment.
The 2nd method is to blend the constituents in either a low or high-speed mixer and then transfer the powder to a melt compounder. This may either be a compounding extruder, or other special equipment for making 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 made as dispersions of very fine PVC polymer particles in liquid organic media. PVC compounds are manufactured into products using many different processing methods that include extrusion, injection moulding, blow moulding, calendering, spreading and coating.