Polyvinyl chloride (PVC) is really a versatile and resource efficient thermoplastic together with the widest selection of uses of some of the plastics family rendering it useful in practically all areas of human activity.
Without additives pvc pellet would not really a really useful substance, but its compatibility with a wide array of additives – to soften it, colour it, make it more processable or longer lasting, results in a wide range of potential applications from car underbody seals and versatile roof membranes to pipes and window profiles. PVC products can 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-made to suit the requirements of each application. Unlike other thermoplastics, the vast majority of PVC applications possess a lifetime which is between 10 and a hundred years. This involves proven durability and stabilisers play an essential part in achieving such performance. All polymers require stabilisers of one sort or any other; PVC is no different in this respect.
Before PVC can be done into products, it should be along with a variety of special additives. The essential additives for all PVC materials are stabilisers and lubricants; in the case of soft pvc granule, 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. Once the additives are already selected, they may be mixed with the polymer in a process called compounding. One method uses an intensive high-speed mixer that intimately blends all the ingredients. The effect is actually a powder, known as the ‘dry blend’, which can be then fed into the processing equipment.
The second method is to blend the constituents in both the lowest or high-speed mixer and then transfer the powder into a melt compounder. This will either be a compounding extruder, or some other special equipment for producing transparent pvc compound. These develop a melt which, when cool, is cut into granules ready for processing. In the specialised process, liquid compounds called plastisols, are designed as dispersions of very fine PVC polymer particles in liquid organic media. PVC compounds are made into products using various processing methods including extrusion, injection moulding, blow moulding, calendering, spreading and coating.