Caps _ Closures_savings by liuqingyan


									Caps & Closures

By: Thomas Woerndl

Closing arguments

The switch to shorter bottle necks is pushing resin savings for beverage manufacturers,
while substantial progress has been made in the field of injection moulding and dry cap
sterilisation. Tom Woerndl reviews innovations in the caps and closures market

The current value of the global closures market for beverages in PET bottles is estimated at
300 billion units, with an annual growth rate of around 5 percent.
But, as the market grows it also changes, with beverage manufacturers reacting to shifting
consumer trends and an increased thirst for smaller, single-serve products.
With a tightening economy, there’s also a need to embrace raw material and energy-saving
technologies, both for the manufacture and application of caps.

Clean caps cost less

For the sterilisation of caps, French company Claranor has pioneered a pulsed-light
technology as an alternative to chemical sanitisation using either hydrogen peroxide or
peracetic acid.

Pulsed-light isn’t a new, and has been used in various
forms in the food and beverage industry since the 1930s.
In fact, it has been touted as a potential aseptic
sterilisation technique for years, with various pretenders
unable to take a product from R&D through to successful
commercial application.

Claranor has bucked this trend, announcing first
commercial sales of its cap decontamination unit in
2006. The system, which can be used for any type of
beverage closure, including sports caps, features an
optical cabinet that houses reflective material and either one or two high-powered bulbs.
Currently the system has an output of up to 72,000 flat caps per hour although, as business
development manager Gérard Gatt explains, this can be increased substantially.

“With our machine output will never really be an issue, and it will always be able keep pace
with a high-speed filling line,” he says. “An output of more than 90,000 caps is achievable –
it’s just a question of whether fillers need this kind of level.”

The pulsed-light unit is fitted into existing filling lines directly before cap application. A
reflective system is tailored into each unit depending on the cap type, and Claranor reports
impressive results for the decontamination of caps for ultra-clean, extended shelf-life and
aseptic applications. Its findings were validated last year by the Fraunhofer Institute, based

in Germany, which found mean log reduction ranging from 3.8 to 5.3 for voltages of 2,000,
2,500 and 3,000.

Calranor’s system benefits from being totally dry, while boasting a small footprint and
minimal change parts. Indeed, the lamp is the only component of the system that needs to
be changed – on average after 10 million flashes.

“With our system there are limited operational costs, the decontaminati on of caps is fully
traceable, and there is absolutely no use of water or cleaning media,” notes Gatt.
Established in 2004, Claranor has already undertaken a number of installations around the
globe, including extensive work with food giant Nestlé in France, Saudi Arabia, the US and

Its installation of a system at Nestlé Waters in Mexico achieved a 5.3 log decontamination
level – comparable to aseptic sterilisation of caps. Here, the Claranor unit has been
integrated into a Zalkin capper with 4 closures sterilised at a time.

Another major breakthrough for Claranor will be realised if the company achieves aseptic
levels for sterilising bottle performs using pulsed-light. “This is something that we’re
working on with the major filling line manufacturers,” adds Gatt. “We have the technology,
so hopefully a commercial application is around the corner.”

Reducing resin

While the past few years has seen moves towards a reduction in cleaning materials and
water usage, light weighting and raw material reduction has also been at the forefront of
the plastics packaging industry.

It’s a strategy that makes sense – particularly in a challenging economic environment – with
the requisite resin and energy cost savings.

For the beverage industry, closure manufacturers have been making the switch to shorter
28mm PCO 1881 necks for plastics bottles, which are now becoming the standard for the
carbonated soft drinks (CSD) and beer sectors.
Smaller necks fit with an increased demand from consumers
for single-serve packaging, with the majority of product
launches in the last five years sized 50cl or below.

While the drive towards resin reduction continues, closures
must also meet stringent packaging requirements
demanded by brand owners. These include product integrity
against contamination, comfort and security to the end
consumer, protection against oxygen ingress for freshness
and longer shelf-life, venting to prevent explosion, and
effective tamper evidence performance.

In the early stages of light weighting, closure specialist Bericap developed an alternative for
the 28mm closure fitting to the PCO 28 neck, which is known as SuperShorty and suits the
newly developed PCO 1881 neck.

SuperShorty is available in two different designs: one with a crown look, the other with a
traditional CSD appearance. According to Bericap, the SuperShorty crown is aimed at
brewers which fill beer into PET, but also at CSD manufacturers considering smaller
packaging formats.

The success of SuperShorty, launched in 2006 and suitable for bottles up to 2-litres, pushed
the industry move towards shorter necks PET bottles forward, with many sports beverages
and flavoured waters now using the 28mm standard for push-pull sports closures. Major
brand owners that supply retail chains have already started to change over to the new neck-
finish in order to save materials and reduce carbon footprint.

Along with Bericap, Swiss closure manufacturer Corvaglia is at the sharp end of this growing
market, having developed a multi-cavity mould tool to produce 3-piece push-pull sports
caps for the 1881 neck-finish. This means that Corvaglia is now able to supply up to 300
million caps annually for the new shorter neck.

Resin savings offered by the PCO 1881 are significant, and Corvaglia estimates the new
standard saves about 1.4g in the PET neck and 0.7g in the HDPE cap. With resin prices rising,
such material reductions offer timely relief for beverage manufacturers, with savings of €3
million on a production run of one billion bottles achievable by using the short neck.
Corvaglia says that a number of beverage manufacturers, including multinationals, have
selected the PCO 1881 as their new global standard. “We have seen strong support for this
technology in Italy and Germany, where a number of sparkling mineral water fillers are
using the short PCO from Corvaglia. Major fillers in Brazil, Mexico and Poland are also now
on board,” says Corvaglia’s president Romeo Corvaglia.

As well as offering resin savings, the PCO Corvaglia cap is said to benefit from a low cost of
conversion from existing neck finishes.

Compression or injection

Caps are usually manufactured by two means: compression moulding or injection moulding,
with closure manufacturers traditionally favouring the more energy-efficient compression

Plastics packaging company Husky estimates that in 2000, 65 percent of plastics closures
produced for the beverage industry were compression moulded. However, as injection
moulding techniques become less energy-dependent, this figure is currently estimated at
slightly above 50 percent.

Cap manufacturers now say that that the energy gap between injection and compression
can be as close as between 10-15 percent. Improvements in technology, including changes

to nozzles and screw design, are helping to make injection moulding more efficient, allowing
lower melt temperatures than were previously possible.

Husky says that, in terms of raw cycle time for one-piece closures, the two technologies are
comparable and, as the weight of closures becomes increasingly lighter, even tighter
tolerances are now required to make consistent caps with less scrap.

As such, injection moulding is now the preferred solution for one-piece closures, as brand
owners demand higher performance and the need for tight tolerances. Compression
moulding, on the other hand, has gained momentum in the more basic two-piece closure

“Because injection is a more sophisticated process than compression moulding, for complex
products, such as two- or three-piece sports closures destined for aseptic and hot-fill
applications, injection moulding is often the only option,” explains Thomas Anderegg,
general manager for marketing and sales at injection moulding specialist Netstal.
On the basis of just energy consumption, as Huksy states, compression will generally fare
better, although there are other components that go towards the finished part, and new
generation high-performance injection closure systems can compete in total cost per
produced unit with a compression system.

“Output of 2,000 parts per minute for a single injection moulding system is not uncommon,”
says Mark Fitzpatrick, Husky’s business manager for closures. “Also, as a processor you have
to consider that injection moulding adds versatility because different closures, as well as
other packaging articles such as pails or tubs, can easily be made on the same system.
Injection moulding also allows for quicker product changeover, which significantly increases

In terms of closure materials, there have been significant improvements to both resin –
including the introduction of new grades of HDPE – and also machinery.
New bi-modal and multi-modal HDPE materials with high stress scratch resistance make it
possible to go even lower with cap weights. They also fulfil cap performance requirements
which, when running fast cycle times in a high cavitation sector like beverage closures, is
vitally important.

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