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13-11-09
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The Berlinale of the Cup and Tube Industry

Helping the plastic container printing industry through the crisis

Zeller+Gmelin GmbH & Co. KG has now organised it's customer seminar for the decoration of plastic containers each year for the last seven years. This year's event took place in the federal capital Berlin in early summer under the heading "The Future of Container Decoration". With nearly 200 participants from more than 20 different countries the seminar was fully subscribed. The lectures mainly addressed the question of what challenges container decoration faces in the future. Here, the aspect of migration with food packaging was a main focus as a subject which is gaining more and more importance.  The information on innovations in this market segment as well as the trade exhibition which was organised to run in parallel with the lectures and where 15 companies from the industry presented themselves, were also found to be very instructive.

The innovative strength of the industry was also addressed by Andreas Mahlich, CEO Marketing and Sales at Zeller+Gmelin, in his opening remarks. He reminded the participants of the discussion about the photoinitiator ITX which was relevant during the time of the previous event in Stuttgart. Only four months later the printing ink specialist from Eislingen had a new low migration ink series in the market. In Berlin, Andreas Mahlich was able to present the new generation of low migration UV-ink series, Uvacurid C71.

The lecture programme started with  a presentation by Marcus Ruckstädter, Sales Manager (export and inland sales) at Zeller+Gmelin and Thomas Reiner, CEO of Berndt & Partner who presented a survey of trends and developments in the field of packaging. By means of prominent examples they demonstrated how incorrect projections can be. They warned against overestimating the crisis based on the current reports. Despite numerous symptoms for a crisis situation, which have to be addressed to in the short term, companies should by no means forget two things. On the one hand processes of innovation and adjustment to the market should not be affected by organisational changes as this would definitely have long term repercussions. On the other hand companies should not forget their strategic concept which has to be directed far enough towards the future.

Budgets are moving in favour of packaging

In the opinion of Thomas Reiner current developments open up good prospects for packaging. Whereas sales of advertising agencies are declining, agencies specializing in the field of packaging are recording increasing turnover. He explained, that many budgets from the sector of classical or TV advertising  are moving to packaging equipment, because this way it is easier to realise an integrated communication system.

Classical agencies are primarily concentrating on optical awareness but in contrast, good packaging designers, by the choice of material and creative processes, are also able to reach the other human senses such as touch, smell, taste and hearing. In this way, the packaging comes very close to approaching people's needs.

Complex subject of migration

An important need of the consumers is the subject security. This applies particularly for food where consumers always react in a very sensitive way when cases of migration are made public. Which legal guidelines and regulations are relevant to food packaging and which responsibilities result from this for the individual involved was explained by Dr. Heinz Schweiger, Zeller+Gmelin. During his lecture he went into the most important rules like the regulation (EG) no. 1935/2004, the so-called framework regulation as well as the plastic directive 2002/72/EU and the respective additions issued 2007/19/EU. In this connection he also explained the levels contained in the plastic directive like SML - Specific Migration Limit and OML - Overall Migration Limit with their corresponding limit values. Moreover the GMP-directive 2023/2006/EG which defines rules for good manufacturing practice (GMP) for all materials and articles which come into contact with food is also relevant.

In order to be able to adequately meet the complex demands required by law, it is indispensable in the opinion of Dr. Schweiger, that everybody involved in the process chain - from raw material supplier and providers of foils, paper and printing inks to the printers and packers assume responsibility for their particular field. Zeller+Gmelin, for example, is offering low migration printing inks which are recommended by food company Nestlé in their corporate regulations (Nestlé Guidance Note on Packaging) for the use with food packaging.

Dr. Schweiger is still seeing a need for action regarding the difficult subject of chemical analysis. Problems are caused due to the fact that there are different test methods which are not harmonised within the industry. Moreover, some test methods are unsuitable for certain packaging. Migration tests which are carried out at 70°C are unsuitable for polystyrene cups as the cups are subject to structural deformation at this temperature.

New ink generation in practical test

Hans-Ulrich Lindner, Zeller+Gmelin, reported on a practical test by means of which Zeller+Gmelin analysed differences in quality with usual glossy coatings for cups made from polystyrene.  For this PS-cups and a cup without a glossy coating as well as a cup made from polypropylene were printed with a standard ink from the Uvacurid series and with  a new ink type. Hans-Ulrich Lindner explained the content of the test and the criteria against which the printed samples have been evaluated. In his summary he mentioned that, for instance, the dot gain with a raster with 5 % at 40 l/cm was higher with corona pretreatment than without. The screen dots with corona tend to be flater and thinner and seem to be frayed. The new Uvacurid ink showed improved values of adhesion and resistance to ethanol in comparison to the standard ink. With the migration analysis all results of all cup samples were below detection limit of 10mg/kg. Zeller+Gmelin has meanwhile optimised the new ink for production and is offering it to the customers under the name of Uvacurid C71. All the inks from this series are free from ITX, DETX and benzophenone (derivatives) and suitable for all market standard printing substrates like PP, PE, PS and PET. The optimised curing speed - in the practical test 600 cups per minute were printed - facilitates an increased productivity. Furthermore, the runnability was improved so that, for example, negative types remain longer open. Also the mechanical resistances like scratch, scotch tape and abrasion resistance are clearly higher.

Peering over the rim of the proverbial teacup to shrink sleeves

Even though direct printing, as with all previous events, was the focus of the subjects that were discussed Zeller+Gmelin traditionally again used the opportunity to peer over the rim of the proverbial teacup of the market segment and to give an idea of alternative possibilities of decoration. In this lecture John Fehrenbacher from Zeller+Gmelin presented the the subject of product decoration by means of shrink sleeves. Within the market share of the various label technologies, shrink sleeves are rank behind self-adhesive labels (46.3 %) and wet glue labels (35.8 %) with 14.4 % in third place. The speaker compared the pros and cons of the most important shrink sleeves PVC, PET and OPS.

Gravure printing is mainly used for the production of shrink sleeves (market share 70 %). One quarter of the products are printed with flexo printing process with solvent-based inks. In this sector the share of UV-flexo printing is continually increasing and has now reached around 10 %. Offset and digital printing have together reached 5 %. The usual printing speed is at 250 m/min. In addition, John Fehrenbacher described the further production steps to the readily decorated packaging as well as the various benefits of this decoration method.

IML-technology offers new options

A further option of container decoration is in-mould labelling (IML). Claus Weinert, Illig Maschinenbau GmbH, informed delegates about a new system of thermo forming which is offered by his company for IML-technology. The possibilities that are opening up by means of the c production line type RDML 70 was demonstrated by him by means of a video with detailed slow motion sequences of the various subprocesses. He presented the different decoration possibilities for round and square products and went into customer benefits of the new thermo forming system. The mentioned advantages varied from a higher print quality and the simple changing of design during running production and a possible application of a barrier layer over the entire surface (EVOH) to reduce product costs.

New technologies in the field of printing machines

After the detour to the market segment of in-mould labelling, Walter Dutly of Polytype SA in Switzerland concentrated again on direct printing. He specified new developments in the field of printing machines and described where the machine manufacturer's responsibility regarding migration is and which individual parameters are exerting influence in this respect. Moreover, with the future development of printing units, Walter Dutly considers the use of a short inking unit as possible.

After Walter Dutly, Sigfried Joneleit, also from Polytype SA, continued and presented the decoration and lacquering machine RDA 24-300 for printing tubes in the dry offset process. Furthermore, he portrayed the hot-transfer process as an alternative decoration method for tubes by means of which a very high print quality can be realised. Compared to labelling, there is no additional component applied to the container but the ink layer only is transferred via contact pressure and heat. For this application, Polytype has designed a corresponding module.

To conclude his lecture, Sigfried Joneleit still picked up on the subject tube printing with flexo printing machines as he defined the challenges which are issued to the printing process in this market sector. Recently, the company has developed a flexo and screen printing machine for the printing of tubes. It will be introduced at the Open House at Polytype in autumn 2009.

More standardisation claimed for cup printing

The series of lectures of machine manufacturers was continued by Hedzer Steensma from Van Dam Machine B.V. from the Netherlands. With regard to the subject of system security he remarked that with machinery directive 2006/42/EG and CE-marking legal rules also have to be complied with as with food safety. Even though the obligation for complying with regulations is spread throughout the supply chain, still much responsibility is concentrating on the printing machine for all components like printing ink, printing plates, substrates etc. are meeting there.

With a view to other segments of the printing industry he also claimed more standardisation for cup printing. According to Van Dam's opinion it was still sufficient to achieve a good printing quality 20 years ago, today the growing challenge has to be mastered to guarantee a safe and environmentally sound printing production. Afterwards Hedzer Steensma described what the ideal machine for cup printing would have to look like and which details have already been realised today by his company. As examples he mentioned solutions like the automatic roller cleaning system, pre-inking during machine set-up, a system against ink misting, etc.

Does flexo printing find its way into tube printing?

The main focus of Massimo Verona's lecture from Omso SpA from Italy was on the question of whether flexo printing - the prevalent printing process in packaging printing - will also find its way into tube printing. The speaker went into detail and portrayed the history of the procedure and explained the process with its individual parameters. He referred to the advantages which for example narrow web printing is utilising in the field of labels. However, here the applied roll-to-roll production is carried out on webs in the wet-on-dry procedure. Due to the fact that this method shows too many disadvantages with the printing of tubes, Omso concentrates on the question of what a machine for cup printing would have to look like. Their considerations go in the direction of choosing a circular arrangement instead of a linear configuration. According to Massimo Verona this technology could also be used in cup printing as well.

UV-measurement - more safety with curing

UV-technology for the curing of printing inks and varnishes plays an important role with the subject safety in cup and tube printing. Reto Huber from Uviterno started his lecture by describing the general conditions for printing plants which have tightened compared with the past. As a first step for more safety he recommended UV-measurement. Here various questions are coming up.  He explained important criteria for UV-measurement like degree of efficiency, dose, performance or reflexion. Reto Huber reduced it to the simple formula „where, what, how, by which means" , or  "where to be measured, what to be measured, how to be measured and by which means?" In addition there are numerous parameters influencing a measurement. These include the measuring range in the UV-spectrum, measuring device and position of device as well as settings of the machine and UV-system and the evaluation of the measurement.

The quality of UV-curing is determined by a great many different influences. Therefore, Uviterno has developed their own patent-protected system for process control where relevant measuring points  and data are recorded and allocated and archived with a suitable algorithm in the UV-control. The data can be saved and therefore be available as reference production data at any time.

In order to bring his lecture to a close and consistent with the end of the event, Reto Huber still brought up a subject with LED-UV-technology to which the future in the field of UV-curing will possible belong. But his explanations also confirmed that it is still a long way beifre it has a practical use in cup and tube printing.

However, the event in Berlin also demonstrated that despite the crisis, the seminar series of Zeller+Gmelin on the decoration of plastic containers once again was crowned with success. The printing ink specialist from Eislingen has established in this niche market a traditional event with international reputation which definitely will be continued.