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Shrink wrap, also shrinkwrap or shrink film, is a material made up of polymer plastic film. When heat is applied to this material it shrinks tightly over whatever it was covering.

Shrink wrap is commonly used as an overwrap on many types of packaging: CDs, DVDs, cartons, books, beverage cans, large appliances, pallet loads, etc. It can be the primary covering for some foods such as cheese and meats. It is also used to cover boats after manufacture and for winter storage.

Heat-shrink tubing is used to seal electric wiring.

Shrink bands are applied over parts of packages for tamper resistance or labels. It can also combine two packages or parts.

The most commonly used shrink wrap is polyolefin. It is available in a variety of thicknesses, clarities, strengths and shrink ratios. The two primary films are either crosslinked, or non crosslinked. Other shrink films include PVC and several other compositions.

Coextrusions and laminations are available for specific mechanical and barrier properties for shrink wrapping food.

Current trends are to improve film properties which may lead to reduced caliper (source reduction) and to improve process efficiency (cost and energy savings).

A shrink film can be made to shrink in one direction (unidirectional or mono-directional) or in both directions (bidirectional).

Films are stretched when they are warm to orient the molecules from their initial random pattern. Cooling the film sets the film's characteristics until it is reheated: this causes it to shrink back toward its initial dimensions.

Shrink wrap is applied over or around the intended item, often by automated equipment. It is then sent through a heat tunnel or oven for shrinking. Heat guns are also used for large items.

Shrink wrap can be supplied in several forms. Flat rollstock can be wrapped around a product, sometimes with a form-fill-seal machine. Centerfold film is supplied on a roll but is two thicknesses with a fold along one edge: the product is placed in the center portion, the remaining three edges are sealed, and the package is sent for heat shrinking. Some shrink wraps are supplied in pre-formed plastic bags with one end open: the product is placed in the bag, sealed, and sent for heat sealing. Some food producers flush the bagged food item with gas or use vacuum prior to sealing and shrinking.

• Packaging
• Stretch wrap
• Shrink wrap contract, legal term
• Shrink Rap (disambiguation)

• Brody, A. L., and Marsh, K, S., "Encyclopedia of Packaging Technology", John Wiley & Sons, 1997, ISBN: 0-471-06397-5