The shrink wrap process involves two stages the enveloping of the pack in shrink wrap either totally or partially and the application of heat to the shrink wrap film which activates the materials memory of its non-stretched molecular chains.
The application of shrink wrap can be divided into two principal types transit and display.
The purpose of transit packaging is to offer the lowest cost option for packaging. The material used is almost exclusively polyethylene, which will provide the appropriate strength at the lowest available cost. A typical application is the collation of individual packs with or without tray support. The most frequent use of the forgoing involves the packaging of a quantity of cans or bottles or cartons for distribution.
The equipment used involves a sleeve or bundle sealer working in conjunction with a shrink tunnel. Two rolls of material produce a sleeve of film around the pack, which is then processed through the tunnel. Generally, these open sleeves do not cause any disadvantages to the pack integrity although a modification can be made to the tunnel whereby an attempt is made to have the hole closed through...