Polyvinyl chloride (PVC) is a versatile and resource efficient thermoplastic together with the widest variety of uses of some of the plastics family so that it is useful in almost all regions of human activity.
Without additives pvc compound would not be a really useful substance, however its compatibility with a wide array of additives – to soften it, colour it, ensure it is 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 might be rigid or flexible, opaque or transparent, coloured and insulating or conducting. There is not only one PVC but a huge family of products tailor-designed to suit the requirements each application. Unlike many other thermoplastics, the majority of PVC applications have got a lifetime which is between 10 and a hundred years. This calls for proven durability and stabilisers play a crucial 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 needs to be along with a range of special additives. The main additives for those PVC materials are stabilisers and lubricants; with regards to upvc compound, plasticisers can also be incorporated. Other additives which might 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 the product. After the additives are already selected, they can be blended with the polymer within a process called compounding. One strategy uses an intensive high-speed mixer that intimately blends each of the ingredients. The result is a powder, referred to as a ‘dry blend’, which can be then fed into the processing equipment.
The second technique is to blend the constituents in either a low or high-speed mixer after which transfer the powder into a melt compounder. This may either be a compounding extruder, or another special equipment for making pvc compound. These produce a melt which, when cool, is cut into granules ready for processing. In the specialised process, liquid compounds generally known as plastisols, are designed as dispersions of very fine PVC polymer particles in liquid organic media. PVC compounds are produced into products using a number of processing methods that include extrusion, injection moulding, blow moulding, calendering, spreading and coating.