Cap,
Straw, End-of-line –
All that’s
wanted is a good bond
Challenging
ambient conditions for adhesive manufacturers
Beverages not only come in endless
flavours, they are also supplied in many different packages, and especially the
carton units for liquid beverages come in endless varieties of shapes. This is
where the adhesives used play a very important role.
It
may be that the consumer behaviour has become more demanding over the years, in
accordance with the different group of buyers and their and situation in life,
but two factors remain crucial at all times for every version of package: the
perfect appeal and the practical handling of the goods. A major factor of
influence for these two aspects is the performance capacity of the adhesives
used.
Illustr.
1: Straight Straw - U-Straw - Telescope-Straw - Jowat AG bonds all varieties of
straws
In
addition to the raised expectations of the end consumer, the entire beverage
market is characterised by global growth, tough competition and the necessary increased
production efficiency resulting from this. Additionally, we find a huge variety
of diverse packages and a consumer behaviour that differs widely around the
globe. This market has accelerated in complexity and dynamics, and this applies
equally for the respective adhesive applications, especially the carton packages.
These
carton packages and their additional components – caps and straws – are undergoing
fast changes in design and functionality. Good examples for the increased
complexity can be seen in the very different container contents, the various package
geometries and the manifold packaging materials.
For
bonding caps, straws and secondary packages, the adhesive manufacturer has to
respond to challenging conditions, not only in the manufacture but also during
the transport and storage of the beverage cartons.
Adhesive
systems
Thermoplastic
hot melts have for a long time been the answer to the requirements from
manufacture and logistics. A few years ago, the polyolefin-based adhesives, a relatively
new product family, came on the market. Due to their excellent processing characteristics,
they are gaining increasing market shares.
The
modern PO adhesives of the Jowat-Toptherm® series were conceived as
specialists for each specific application. Stable in the melt, minimal odour formation
and nearly colourless in processing, and a high green strength are the
outstanding properties of this product group. The excellent flexibility at low
temperatures and wide adhesion spectrum also with minimal grammages applied are
additional features.
Speed
and small bonding surfaces
The bonding
of caps and straws have the same basic requirement: They need to be attached to
the beverage carton at line speeds that are constantly accelerated. This requires
adhesives with a high green strength, the major prerequisite for safe and
flawless downline processing.
Challenging
conditions in production (like heat, cold, water etc.) need an adhesive which
will remain unchanged when exposed to these kinds of stress. An optimum bond
must still be guaranteed when hot filling is followed by chilling, and this means
that stretching, shrinkage and condensation water will accompany the bonding
process.
Over
the past years, not only the line speeds have accelerated, but the number of
different materials on both sides of the adhesive has also multiplied. Foil
materials laminated to the carton, caps with different application substrates,
or straws in diverse shapes and foils, require high-tech adhesives with a wide
adhesion spectrum.
Cap
bonding
Not all caps are equal, and
the endless variety which is standard for this application is not found
elsewhere. Adhesives had to match these many different caps and application
methods for many years. No matter if the caps are of the flip-open or twist-off
variety, whether the formats are standard, premium with very special shapes,
with or without headspace – all closing systems for beverage cartons are
matched by the safe and universal adhesive partner, Jowatherm®
250.00. This hot melt adhesive can of course be used for applications with
direct food contact (according to FDA 176.170 and EU 10/2011).
One specialty: Jowatherm®
250.00 is supplied in pillows. Pillows are highly processor-friendly and have
many advantages compared to blocks: They are easy, clean and time-saving in
their handling, since the manual removal of blocks from the silicone paper is
no longer necessary, also making any considerations of contamination by this
paper and of its expensive disposal obsolete. The risk of splashing and
possible burns while refilling the melters is clearly reduced. The pillows also
ensure an even and fast melting process with minimal cooling down of the melt.
This adhesive system has been tested and is approved for the cap applicators of
the well-known leading companies on the market.
Straw
bonding
Another example for the
growing demands in the process of beverage packaging is the attaching of straws
to portion packs. When feed speeds are high and ambient conditions are
challenging (cold, moisture), very different materials also have to be bonded
with high green strength to ensure safe downline processing. There are,
however, additional factors to make this a highly complex production step. Just
like the beverage cartons, the straws (telescope, U-straw, straight straw) and their
foil wraps (OPP, aluminium etc.) come in enormous varieties of shapes, sizes
and surface structures.
On the way to the consumer,
the straw bonding on the individual portion packs has to also withstand extreme
stress conditions and must remain fully attached while running through the
subsequent packaging, transport and handling processes, where high mechanical
impacts are exerted. In the course of the packaging process (conveyor belt
transport, multipack assembly by shrink foil wrap, tray packaging and pallet
sorting), the attached straws are constantly exposed to pushing, shaking and
swiping impacts. This is where a powerful adhesive can show its superior
strength and reliable reproducible bonding results.
Straw attaching to portion
packs - this means a lot of applications expertise in bonding on minute
surfaces. The response to this adhesive challenge is provided by Jowat AG with
its modern PO hot melt adhesives: the Jowat-Toptherm® family, with
an outstanding example, Jowat-Toptherm® 256.05. All adhesives from
this series offer excellent adhesion on the most diverse substrates with a high
green strength, and in consequence an efficient straw attachment.
The Jowat-Toptherm®
products meet the regulations concerning packaging of food under EU guideline 10/2011
and the FDA requirements.
Secondary packaging and transport of the
beverage cartons
When
high-quality cartons are manufactured with surfaces that are difficult to bond,
for example coated papers, water-repellent Kraft liners and lacquers, the
demands on the adhesives multiply again. This is where the polyolefin
(PO)-based adhesives have again proved their powerful and flexible character. Jowat-Toptherm®
256.50 has the respective adhesion spectrum and a higher heat resistance, and
can replace the combination bonding that was the standard so far (hot melt and dispersion
adhesives).
However,
attention must also be paid to the forces which the bond has to withstand later
on during transport and storage of the packs, respectively of the pallets. The
stress exerted on difficult substrates, with high mechanical impacts on the
entire compound (due to belt conveying, shrink foiling, packaging in trays, and
truck or container transport), requires a superior strength and solidity level
of the adhesives as well as a high flexibility.
Conclusion:
The
purchaser is expecting a package that is perfect in design and handling, with
components that match the product promise of a pure enjoyment of a beverage.
Whether Pak or block, cap, straw or end-of-line - the tried and proven Jowat
adhesives have for many years fulfilled these requirements and continue to do
so. Perfect bonds increase production security, product quality, and customer
satisfaction.
Illustr.
Timeline development of beverage caps
Manuel
Füstmann
Graduate
engineer (Diplom-Ingenieur) and Product Manager, responsible at Jowat AG for
global marketing of adhesive products for the packaging industry.
