Polyvinyl chloride (PVC) is a versatile and resource efficient thermoplastic using the widest variety of uses of the plastics family making it useful in virtually all regions of human activity.
Without additives pvc granule 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 more durable, results in a broad range of potential applications from car underbody seals and flexible 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-created to suit the requirements of each application. Unlike other thermoplastics, the vast majority of PVC applications use a lifetime which is between 10 and 100 years. This requires proven durability and stabilisers play an important part in achieving such performance. All polymers require stabilisers of a single sort or some other; PVC is not any different in this respect.
Before PVC can be made into products, it has to be coupled with a variety of special additives. The primary additives for all those PVC materials are stabilisers and lubricants; in the case of soft pvc granule, plasticisers will 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 from the product. Once the additives are already selected, they may be blended with the polymer in a process called compounding. One strategy uses an intensive high-speed mixer that intimately blends every one of the ingredients. The outcome is actually a powder, known as the ‘dry blend’, which happens to be then fed into the processing equipment.
The second strategy is to blend the ingredients in either the lowest or high-speed mixer and after that transfer the powder into a melt compounder. This may be either a compounding extruder, or another special equipment for creating transparent pvc compound. These develop a melt which, when cool, is cut into granules ready for processing. Inside a specialised process, liquid compounds referred to as plastisols, are designed 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.