Stretch wrap is a thin linear low density polyethylene (LLPDE) or low density polyethylene (LPDE) plastic sheet or film that can be tightly wrapped around items to secure them firmly together in place or on a pallet for shipping. This plastic film is applied using a hand-held wrapper, a semiautomatic wrapper machine, or a fully automatic wrapper machine. For objects, boxes or items stored or shipped on a pallet, the stretch wrap process unitizes the pallet, effectively connecting all individual items into a single, large "palletized" module. Tackifiers, added during the manufacturing of the plastic wrap, allow the wrap to cling but not stick to the items on a pallet. These palletized units offer a more secure and efficient means of storing and shipping items of all sizes.
Hand-held stretch wrapping tools allow an individual to apply the wrap to a pallet's contents manually. Fully automatic or semiautomatic machine stretch wrappers are more expensive but provide a tighter package than hand-held applicators. There are two types of wrap films. Blown films melt the plastic and blow it out in a thin sheet which tends to appear more hazy, allows less light through, and provides better resistance against punctures. Blown stretch wrapping is slower and more expensive but provides a better quality wrap. The cast stretch film process is faster, provides better resistance against tears but less load unit stability, less tamper resistance, and less protection against moisture and dust.
Using stretch wrap or shrink wrap allows a number of loosely stacked items to be combined and secured into a single, unitized pallet for shipping or storage. Palletizing these items makes for easier and more efficient transfer from factory or warehouse to semi-truck trailers, flatbed trailers, ocean-going vessels, air transport, and railroad box cars. Palletized units are securely confined which means they can be transported faster using a forklift or other means and are more easily stacked and secured within shipping spaces or storage facilities. Stretch wrap is currently the most cost-effective method to make sure a load remains intact and securely positioned on a pallet.
For objects, boxes or items stored or shipped on a pallet, the wrapping process unitizes a pallet, effectively connecting all individual items into one large, strong palletized unit. Low quality wrap materials may allow a small, single tear or puncture to spread or zipper into longer tears or breaches thus compromising the load integrity of the wrapped pallet. Lower quality stretch wrap may also allow tailing or unraveling, which also compromises load integrity.