Plastic wrap

Plastic wrap, cling film (UK), cling wrap or food wrap, is a thin plastic film typically used for sealing food items in containers to keep them fresh over a longer period of time. Plastic wrap, typically sold on rolls in boxes with a cutting edge, clings to many smooth surfaces and can thus remain tight over the opening of a container without adhesive or other devices. Common plastic wrap is roughly 0.5 mils, or 12.5 µm, thick. In Australia and New Zealand the genericised trademark glad wrap is commonly used, while Saran wrap has become genericized in North America.

Materials used

Plastic wrap was first created from polyvinyl chloride (PVC), which remains the most common material. Non-PVC alternatives are now being sold due to concerns about the transfer of plasticizers from PV into food, although PVC is still the most common. For household use, low density polyethylene (LDPE) is gaining market share as it is much safer.

A number of governments are concerned about the environmental effect of PVC, as the material is said to be toxic and harder to recycle. Nevertheless, PVC is still used as its stretching properties offer excellent food catering presentation on the shelf, and it clings well to more kinds of surfaces. Even so, some countries are starting to ban the use of PVC in toys for infants and food contact applications.

Saran (plastic)

Saran is the trade name for a number of polymers made from vinylidene chloride (especially polyvinylidene chloride or PVDC), along with other monomers. Since its accidental discovery in 1933, Saran has been used for a number of commercial and industrial products. When formed into a thin plastic film, the principal advantage of Saran, when compared to other plastics, is its very low permeability to water vapor, flavor and aroma molecules, and oxygen. This oxygen barrier retards food spoilage, while the film barrier to flavor and aroma molecules helps food retain its flavor and aroma.

History

Polyvinylidene chloride (PVdC) was discovered at Dow Chemical Company (Michigan, USA) in 1933 when a lab worker, Ralph Wiley, was having trouble washing beakers used in his process of developing a dry-cleaning product. It was initially developed into a spray that was used on US fighter planes and, later, automobile upholstery, to protect them from the elements. Dow Chemical later named the product Saran, and eliminated its green hue and offensive odor.