Whitepaper: Shrink Wrapping

Strictly speaking, shrink wrapping is not considered “flexible packaging.” However, wrapping does use flexible film and foil of various materials and combinations. Many of the general considerations for films discussed in previous whitepapers on Form-Fill-Seal and pouching machines will apply to wrapping machines as well.

The film used in shrink wrapping is a typically a single layer polyethylene or polypropylene though other plastics and multi-layer films can be used. It is manufactured so that on exposure to heat, it shrinks by about 30 to 80%. If multiple layers of shrink film are to be used, for example to bundle several shrink wrapped trays, the films must be selected so that they do not bind to each other when heated.

Shrink wrapping is sometimes used as the primary packaging. Some individual foods, soaps and other products may be wrapped directly. More commonly shrink wrapping is used as a secondary or tertiary packaging. An example of secondary use is shrink wrapped six-packs of beverage cans or 24 pack bundles of water.

Wrapping is also commonly used as a tertiary packaging such as overwrapping an individual carton or bundle of cartons. In the past, appearance of the tertiary packaging has not been considered critical important as the customer never saw it. The rise of club stores like Costco and Sam’s Club has changed this. The 6 pack of canned corn is now the unit of sale in these stores and appearance has become critical to branding. Previously translucent grey film was fine since nobody outside of the stockroom was likely to see it. Now, glossy film with registered graphics is needed to catch the customer’s eye using bullseye or end seal wrapping. This affects the choices of machinery that can be used.

Download the complete Shrink Wrapping Whitepaper to continue learning about different types of wrappers.