A stretch hood is a tube of film sealed on one end, which is stretched over a palletized load to secure the contents to the pallet. The film is cut to the appropriate length, heat sealed on the top end, and gathered on four 'fingers.' These fingers stretch the film in the horizontal (transverse) direction until the film dimensions are slightly larger than the load dimensions, then draw the stretched film down over the pallet, unrolling it as they go. By varying the unrolling rate, a degree of vertical (machine) direction stretch can be obtained to better hold the load on the pallet. At the bottom of the pallet, the fingers release the film, which typically wraps under the pallet bottom.
Stretch hoods are one of the fastest growing pallet stabilization and packaging systems, with current North American volumes around 60 million lbs/yr and a greater than 20% growth rate. Load stability and the flexibility to control elasticity and holding force make stretch hoods ideal for palletizing many applications - from empty PET bottles (high elasticity and low holding force) to cement bags (low elasticity, high holding force).
Building materials and heavy-duty shipping sacks in particular have seen a rise in popularity of stretch hoods. Specific applications include: bricks, stones, shingles, bagged concrete, and bagged resin. And, appliances have also seen high growth of stretch hoods (at the expense of corrugated board).
Stretch hoods offer the most comprehensive list of palletizing benefits, including:
1) Logistics management - The stretch hood process is more efficient (100 loads per hour for stretch hood vs. 60 loads per hour for stretch wrap).
2) Weather-ability - Five-sided protection ensures products stay dry and provides protection against ultra-violet radiation.
3) Package integrity - Load stability and abuse resistance mean a greater likelihood products arrive to their final destination unscathed and attached to the pallet.
4) Display properties - The clarity of the film and the fact that a stretch hood is a single layer of film (vs. multiple layers of stretch wrap) help the logistics function identify errors or product damage and enable constant brand exposure.