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In our July issue we looked at the subject of wraparound
labels. In this issue we turn our attention to sleeve labels, and in
particular to shrink sleeves of the type made by Decorative Sleeves, part of
the ITW Group, who invited us to visit their plant.
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There is a clear distinction
between the two types of sleeve label (i.e. stretch sleeves and shrink
sleeves) used in the beverage industry. Decorative Sleeves, headquartered in
Kings Lynn on the UK’s East coast, is a specialist manufacturer of shrink
sleeves – a labelling option with its own unique features and some distinct
advantages for bottlers. To make the distinction clear we will first take a
brief look at stretch sleeves.
Stretch sleeve labels, made from
polyethylene, are widely used on PET bottles. They are supplied on a roll, as
one long continuous sleeve which is cut to the appropriate length and pulled
over the bottle by a special purpose sleeving machine. Originally conceived in
the 1970’s, stretch sleeve labels have the the major advantage over wet glue
and wraparound labelling that they require no adhesive. Hence, in addition to
accelerating the labelling process on line, they are more environmentally
friendly and ideal for refillable bottles, being easy to remove and leaving no
adhesive residue on the bottle.
During the latter part of the 1990’s
several machinery suppliers, including Krones, PDC and Comag, developed
stretch sleeve labelling machines to serve this growth market and PE stretch
sleeves, with their high production speeds, have found widespread popularity
amongst beverage fillers across Europe. In the United Kingdom the stretch
sleeve has enjoyed more limited success largely due to the fact that many
fillers had already decided on the wraparound option when high speed sleeving
machines appeared in the nineties, but sleeve manufacturers anticipate
increased demand with the next re-equipment cycle.
Shrink sleeves,
manufactured by companies such as Decorative Sleeves, exploit a different
market niche. Shrink sleeves slide over the bottle in a similar way, but are a
very much looser fit, with no stretching involved. A second process – heat
shrinking – then causes the label to mould itself to the shape of the bottle.
Naturally shrink sleeves are therefore of particular interest for use on
unusually shaped containers, especially where a full height sleeve is
required. Heat set PET bottles, which frequently include shrink panels and
other irregular features, immediately spring to mind as a suitable application
for shrink sleeves. |
Decorative Sleeves
Decorative
Sleeves, like its sister company Auto-Sleeve in Austria (who manufacture both
shrink sleeves and stretch sleeves), is a member of the US based conglomerate
Illinois Tool Works Inc. (ITW), who took over Decorative Sleeves in 2000.
Decorative Sleeves is focused exclusively on shrink sleeves and currently
supplies some 3,500 million individual shrink sleeve labels (including tamper
evident collars) per annum from plants in Kings Lynn and Castelford, numbering
among their clients Nestlé, Parmalat, Coca-Cola and Perrier.
The sleeves
are mostly made from PVC or PET, with OPS being available as an alternative to
the cheaper but not always environmentally acceptable PVC. PET shrink sleeves,
whilst also a little more expensive, have the advantage of a higher gloss and
a higher percentage shrink. An important characteristic of the label material
is that it does not shrink, or shrinks only marginally, in a vertical plane.
This is achieved by stretching the film in one direction only during
manufacture, and taking care to print and cut the labels in the correct
orientation. Thus a label can be cut to precisely the right height for the
bottle, in the knowledge that it will shrink and hug the bottle’s contours
whilst still resulting in a full-height label, if that is what is
required.
And it is the full-height decoration that is one of the major
attractions of a shrink sleeve, giving the container a truly striking image
from top to toe at point of sale – particularly for special limited period
promotions when the shrink label can be applied to existing packs completely
obscuring the normal label. There are even times when unattractive-looking
contents are best obscured by a full-height shrink sleeve
label!
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Shrink sleeves are of particular interest for use on unsally
shaped containers. |
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Refillable mineral water bottles, - an ideal application for
stretch sleeves. |
Striking print quality,
and no scuffing
The depth and quality of print, utilising CI Flexo,
UV Flexo or Rotogravure processes, that can be applied to a film sleeve
produces a truly striking effect. Decorative Sleeves latest investment in UV
technology offers a big advantage in that the ink dries rapidly and so allows
more ink to be applied at each pass, producing a more intense colour than
standard CI Flexo printing and at a reduced origination cost to rotogravure.
The use of clear film material has another, less obvious advantage. The ink
can be applied to the internal surface of the label, which means that the
print is not subject to scratching and scuffing whilst the label is on the
bottle. The no-label look is easily achieved in this way, and where a more
conventional look is required a background of white is applied after the
colour printing to provide opacity. To take account of unusual and irregular
contours in the bottle shape, the printing of text and graphics on the label
is pre-distorted in such a manner that after shrinking the finished result
looks exactly as if it were printed directly on to the
container.
Easy to apply
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For most beverage manufacturers
high speed labelling is the order of the day. There are, of course, high speed
shrink-sleeve machines, but shrink sleeves are also ideally suited to short
runs, such as promotions, which we have already mentioned. There they can
easily be applied by hand if required, without interrupting mainstream
production.
After printing the sheets of film, which is normally between 40
and 70 microns thick, the material is cut into single label width and formed
into one long, continuous sleeve by a high speed solvent welder developed
in-house by Decorative Sleeves. At this stage the sleeve is either rewound
onto a roll and supplied for machine application, (where each label is
automatically cut to length), or individual labels are guillotined to length
and supplied in a cut-and-stack format. It is in this latter form that the
sleeves are supplied for hand application. Because the sleeve material is
reasonably rigid, and at this stage is also a loose fit over the container, it
is not at all difficult to simply slide a sleeve over a bottle. All that is
then required is to pass the container through a heat tunnel, which can be as
simple or as complex as desired. When empty PET bottles are being sleeved
Decorative Sleeves recommend the use of either a hot air tunnel with rotating
bottle nests or a steam tunnel to minimise the impact of heat on the PET
container itself. |
PETplanet publisher GmbH, Landhausstr. 4,
69115 Heidelberg, Germany,
info@petpla.net
tel:
+49(0)6221-65108-0, fax: +49(0)6221-65108-28
© 2003
PETplanet
Publisher
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