Secondary Packaging — Shrink Wrapping, Carton Packing and Palletising

1. The role of secondary packaging

Secondary packaging has three jobs: protect the bottles in transport, present the brand at the shelf, and fit the retailer's handling system. The technology is chosen by the retail format — what the retailer's shelf and warehouse actually accept — and by the logistics (stacking strength, pallet stability). The section sits between the labeller and the warehouse, and it sets the line's end-of-line speed.

The pack decision is made with the retailer and the distributor, not by the line supplier alone — the line follows the pack.

2. Shrink wrapping and trays

Shrink-wrapped trays put the bottles on a corrugated tray, wrap film around them and shrink it — the dominant format for volume PET in water and CSD. It is the lowest-cost pack per bottle, runs at high speed, and the tray adds stacking strength. The film and the tray are the running costs; the shrink tunnel is the line station that sets the pace.

For multipacks and export loads, the shrink wrap is specified with the film's strength and the tray's stacking spec — a pack that fails in the container fails at the destination.

3. Carton packing

Carton packers put bottles into corrugated cartons — wrap-around (the carton wraps around the bottles) or pre-glued cases — and cartons serve glass, higher-end and export formats where stability and protection matter more than pack cost. The carton is the highest-cost pack, and it is the retailer's requirement in many glass and higher-end segments.

The carton's board spec and the packer's changeover are the design points — a glass line's carton spec is part of the safety and the brand, not a commodity buy.

4. Palletising

The palletiser stacks the packs into a stable, wrappable pallet — the end of every line and the point where the load's stability is decided. The pallet pattern, the layer pads and the stretch wrap are engineered for the transport route: a stable pallet survives the journey, an unstable one becomes a claim. The palletiser is specified on the line output and the pallet pattern, with the wrapper following it.

Ask for the pallet stability spec with the proposal — the pattern and the wrap are part of the line's engineering, not an afterthought.

5. The comparison

Read the table by the brand's shelf strategy — volume brands run shrink trays, higher-end and glass run cartons, and every line ends at the palletiser.

6. Choosing by format

The choice follows three facts: the bottle (PET and volume favour shrink trays; glass and higher-end favour cartons), the retailer's requirement (confirm the pack the shelf accepts), and the logistics (stacking strength, pallet stability, export handling). A volume water line in a modern-retail market runs shrink trays; an export glass line runs cartons. Confirm the pack with the distributor before the line is quoted — the machine follows the pack.

Changeover between packs is a real cost on multi-format lines — the packer's changeover time is part of the running economics, worth asking for in the proposal.

7. Specifying the section

Specify the end-of-line section with four inputs: the pack (shrink tray, carton or both), the bottle and pack dimensions, the line output, and the pallet spec for the transport route. Ask for the pack cost estimate, the changeover time and the pallet stability in the proposal — they are part of the line's economics. The section works with the filling machine and the labelling as one line, and the supplier should quote the whole chain.

Frequently asked questions