Polyvinyl chloride (PVC) is a versatile and resource efficient thermoplastic with the widest variety of applications of the plastics family so that it is useful in almost all parts of human activity.
Without additives pvc granule would not be a really useful substance, however its compatibility with an array of additives – to soften it, colour it, make it more processable or more durable, produces a wide range of potential applications from car underbody seals and flexible roof membranes to pipes and window profiles. PVC products may be rigid or flexible, opaque or transparent, coloured and insulating or conducting. There is not only one PVC but a whole group of products tailor-created to suit the requirements of each application. Unlike other thermoplastics, nearly all PVC applications have got a lifetime which is between 10 and a hundred years. This calls for proven durability and stabilisers play an essential part in achieving such performance. All polymers require stabilisers of one sort or other; PVC is no different in this respect.
Before PVC can be produced into products, it needs to be coupled with a variety of special additives. The main additives for those PVC materials are stabilisers and lubricants; when it comes to upvc compound, plasticisers can also be 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 have already been selected, they are combined with the polymer in a process called compounding. One method uses an intensive high-speed mixer that intimately blends all of the ingredients. The outcome can be a powder, known as a ‘dry blend’, which happens to be then fed in to the processing equipment.
Another strategy is to blend the ingredients either in a small or high-speed mixer and after that transfer the powder into a melt compounder. This will be either a compounding extruder, or any other special equipment for making clear pvc granule. These develop a melt which, when cool, is cut into granules ready for processing. Within a specialised process, liquid compounds generally known as plastisols, are produced as dispersions of very fine PVC polymer particles in liquid organic media. PVC compounds are manufactured into products using a number of processing methods which include extrusion, injection moulding, blow moulding, calendering, spreading and coating.