Labelling machines for PET bottles : Comag presents a new range of stretch sleeve machines

Labelling machines for PET bottles : Comag presents a new range of stretch sleeve machines

Thanks to its lower costs and versatility, PET packaging has finally entered milk market. But functionality also lies in "intelligent" labels.

PET's diffusion on the market and its success in areas such as mineral waters and beverages determined an expansion of its use in other sectors, such as milk's.
The use of plastics in milk packaging is still conditioned by the strong presence of carton on the market and by the recent revival of glass, mainly used by companies producing High Quality fresh milk.
However, two factors make plastic as competitive as the other materials: transparency and recycling properties.
The transparency factor, above all, is important in terms of impact with consumers, who, unlike carton packs and the first white PE bottles – can "see" the product and feel as if they can check its quality.
For the same reason, the companies are orienting towards transparent plastic labels, initially applied to glass bottles only and later also to PET bottles, whose production costs are lower than the costs for glass packaging.
These labels are called stretch sleeves: they are made of stretchable tubular plastic material (LDPE): labels are created by folding and welding the printed film.

Through a special optional device that can be applied to some labelling machines, such those produced by Comag – the tubular material thus obtained is pre-cut: this way the separation of labels while they are applied on the bottle can be carried out simply by pulling them from the lower flap.

Since stretch sleeves do not need glue for application, they meet the requirements for a total visibility of the bottles: there are no gluing areas restricting the transparency of the container. Furthermore, the package can be fully recycled, according to EC Regulation "Packaging & Packing Waste" n. 94/62/EC, for which, last April, specific guidelines were approved.

Plastic material labels are recommended for the production of refillable – or returnable – bottles, which may be used for up to eight times, since we are talking of an application which can be easily removed,without leaving traces on the container's surface.


More powerful labelling system

Comag has developed the new labelling machine for stretch sleeves – SLC 400, which is able to work with an output speed of 24.000 b/h.
Tradition and innovation are joined together in a machine which preserves a mechanically-operated multi-head system on-line, like the other models offered by the company, yet it features one more module compared to 18.000 b/h machines: thus a total of four applicator heads is available.
It is the addition of an application unit to increase Comag machines output and not the enhancement of existing units.

This means that single heads, in order to get to the final result of 24.000 b/h as against 18.000 b/h of the previous machines, are not subject to a further load, but they work with a constant stress (max. 100 cpm, i.e. 6000 b/h): on the one hand, product quality is guaranteed since the error possibility that is proportionate to the additional work the machine would perform is strongly reduced; on the other hand the manufacturer is given the chance to work with thinner labels.

Like for the other Comag labelling machines, the project foresees an innovative and mechanical operation which, combined with an advanced engineering technology, allows to have a production and application cycle without in-between label-handling stations: this way, top accuracy and positioning repeatability are ensured, as well as very simple maintenance operations.

Bottle continuous flow mechanic transport allows to work both with full or empty bottles, made of different materials in addition to PET (PE, PVC and glass), but above all with differently-sized and shaped bottles: change-over operations are simple and quick, since only a few elements must be adjusted.