Heating Elements in the Manufacture of Plastic Wrap
Our heating elements are used in the product of plastic wrap and film for food preparation and storage. Please call us on 0121 772 0033 for more information.
Did you know that heating elements play an essential part in the plastic wrapping manufacturing process?
Plastic wrap (known popularly as cling-film) is a type of food packaging consisting of a thin film of flexible, transparent polymer that clings to itself and to food containers to form a tight seal. The plastic keeps the food fresh by protecting it from air and by preventing dry foods from absorbing moisture and wet foods from losing moisture. It also seals in odors to prevent them from spreading to other foods stored nearby.
Most household plastic wrap is made from either polyethylene (a material discovered by accident in 1933 when research workers mixed benzene and ethylene at high temperature and pressure), polyvinyl chloride (PVC), or polyvinylidene chloride (PVDC).
Plastic wrap is made by extrusion. Granules of plastic are heated until they melt at about 212°F (100°C) for polyethylene and about 392°F (200°C) for PVC and PVDC. The liquid is then forced through a die to form a tube of warm, stretchable plastic, made possible by applying heating element technology. At regular intervals compressed air is blown into the side of the moving tube to form large bubbles. This stretches the plastic to the desired thinness. The thin plastic cools rapidly, and the bubble is collapsed between metal rollers to form a film.
With the job of the heating elements complete, the final part of the process sees the film wound around a large metal roller to form a roll that may hold several kilometers of plastic wrap. The plastic film on these rolls is then unrolled, cut to the proper length (usually about 49 feet [15 m]) and width (about 1 foot [0.33 m]), and rerolled onto small cardboard tubes (this rolling, unrolling, and rerolling tends to give the plastic wrap a slight negative charge of static electricity, that helps it cling). The product is then packaged into boxes and dispatched for sale to millions of families worldwide.