At the Cutting Edge of Beverage Filling - Verpackungs-Rundschau

LABELLING
Marketing Label Papers
by Manfred Marschner*
Beyond performing a necessary and legally
required role, labels today have
gained tremendous importance in product
marketing. They convey the value
of a product, contribute to its image,
are the major vehicle of a brand.
Today’s label papers are the result of
a continual development in quality
standards which have to meet a wide
number of challenges in the areas of
print and finishing, labelling, ease
of removal from bottles, and finally
recycling of used labels.
Technical Aspects of Label Papers
Labels are made of one-side coated
papers. A basic distinction is drawn between
machine-coated and cast-coated
papers and between wet strength and
alkali-resistant papers on the one hand
and non-wet strength papers on the other.
Wet strength and alkali resistant
papers are used to label refillable and
one-way bottles In this area, base papers
for metallisation represents a significant
special category.
Non wet strength papers are used for
labelling and packaging under dry and
warm conditions – mainly for labels
and banderoles, but also for chocolate
wrappers, cigarette soft packs, etc. and
for lamination.
Cast-coated papers are used in the labelling
of high-class drinks, such as wine,
champagne, etc., in addition to a variety
of foodstuffs. Their extremely high-gloss
finish bestows on the product a high sense
of value, whilst the uncoated side is
eminently suitable for the labelling process.
Cast-coated papers are also used in
the manufacture of self-adhesive labels.
The European market for one-side
coated papers is about 500000 t, approximately
2.5% of the total paper market. In
recent years, the market for machinecoated
label papers has seen only slight
average growth of 2-3%, whilst sales of
wet strength and alkali-resistant papers
have grown only in line with the low
growth in their application areas. The use
of cast-coated papers in labelling has
stagnated.
*Managing Director of Stora Fine Paper Deutschland
Composition of a Label Paper
Label papers are made up of: base
paper, surface coating and treatment
of the reverse side. Base papers are
predominantly high quality, wood-free
papers. However, papers containing a
small proportion of mechanical fibres are
used in some areas (e.g. for labelling wine
and soft drinks).
The surface coating consists mainly of
pigments and binding agents to achieve
optimal printing characteristics. Further
additives serve to adjust whiteness, water
and alkali resistance, resistance of the
printing inks to wet abrasion, alkali-bath
ink retention etc.
The main purpose of the reverse side
treatment is to reduce as far as possible
curling which results from coating one
side of the paper and to ensure optimum
flatness when the paper is exposed to
varying ambient conditions, adhesive and
moisture. It is also used to adjust water
absorption and wetting properties and
thus adhesive curing times. Finally, it can
be specifically used to influence the diecutting
properties of the paper.
The main properties of label papers can
be divided into the categories “Print and
Finishing” and “Labelling”.
Print and finishing: the optical
qualities of whiteness, smoothness and
gloss are critical to printing quality.Whiteness
and gloss are important for brilliant
colour reproduction,whilst smoothness is
decisive for highly accurate reproduction
and optimum resolution.
Processing characteristics are mainly
influenced by flatness, sheet separation
and the stiffness of the paper.
Label papers are largely offset printed,
but the upper, coated side, must be suitable
for offset and rotogravure printing.
They must also be suitable for subsequent
lacquering with water-based dispersion
lacquers, solvent-based lacquers and
ultraviolet lacquers. For wet strength and
alkali-resistant label papers the printing
ink must be well fixed to ensure good ink
adhesion in alkali-bath bottle cleaning.
Labelling: optimum flatness and good
label separation are basic requirements.
In the case of non wet strength label
papers, good sizing is necessary to prevent
glue bleed when adhesives are applied
to the whole surface. Moreover, these
papers must not contain substances
which might produce corrosion when in
contact with cans. The wet strength level
required of a label paper depends on the
speed of the labelling process and the
filling conditions. Wet surfaces or condensation
must not result in creasing and the
original gloss of the label paper must be
retained. In addition, a label must retain
its good appearance, even when exposed
to condensation or when immersed in
ice-cold water. Especially the so-called
wet opacity (intransparency) is crucial for
the optical appearance of the label under
such conditions.
Another extremely important characteristic
is the alkali-resistance of the
paper. When exposed to the alkaline solutions
used in bottle cleaning, the label
must come off the bottle very quickly yet
it must not disintegrate.
Labelling Trends
In the mid-80s, beer was mainly bottled at
temperatures of between 3 and 4°C. This
resulted in the formation of heavy condensation
on the bottles and produced
a need to use casein adhesives. To avoid
labelling problems, especially creasing,
the water absorbency of the reverse of the
label had to be kept low. Labelling speed
has brought about further changes. These
days, bottling machines are no longer operated
at maximum speed. Today,average
bottling performance is in the order of
45000 bottles per hour. In recent years,
bottling temperatures in many breweries
have been raised to between 10 and 14°C
due to the introduction of ‘flash pasteurisation’
to extend shelf-life and to the use
of sealed crates, which make it necessary
to minimise condensation on bottles.
This development permitted the use of
adhesives with reduced casein content,
making it necessary to modify the water
absorbency of the reverse side of label
papers.
The steadily increasing use of light,thin
glass and light plastic bottles (especially
PET) for soft drinks and mineral waters
represents a further trend.
Germany and other European countries
are now seeing the introduction of returnable
PET bottles.Paper labels are well
suited for labelling this new form of
packaging. ❐
VR Beverage Packaging 1997 29