Sleeve Wrap-shrink Film

This method is used to collate groups of articles for transit purpose. A sleeve wrap requires about 80 of the area of film needed for a complete overwrap.

A loose open ended sleeve is formed around the articles. On shrinking, the contents are rigidly held to form a stable transit pack, and the open ends of the sleeve are useful because they provide hand holds. The main requirements of a transit pack are strength and economy, and these met by polyethylene, which is used almost exclusively for the purpose.

An unbalance film is required for a sleeve wrap. The longest side of the pack is placed on the film in the transverse direction. And a sleeve which is longer than the pack is formed by heat sealing. During shrinking, the machine direction orientation would cause shrinkage along the length of the pack. Excessive transverse direction orientation would cause shrinkage along the length of the pack, and since the ends of the pack are open, a considerable surplus of film is required to prevent the formation of an incomplete wrap. Polyethylene film for sleeve wrapping requires a machine direction shrinkage of 60-80% and a transverse shrinkage of less than 30%.