Focus on film

Nordenia International’s NorCell material, produced using a patented foaming process without reducing the film thickness, is claimed to weigh up to 40% less than conventional flexible packaging film.

Surface structures with unique haptics can be achieved with the foaming technology, and packaging can be made with high puncture resistance, and excellent sealing ability and printability, the company claims. A further advantage is that the reduced packaging weight offers a saving for the customer on transportation costs and, later, with the disposal charges.

The NorCell material technology is being used to produce flexible packaging for the food, petcare, wet wipe, detergent and hygiene markets.

Another Nordenia flexible packaging innovation allows greasy, breaded or bread-like foods to be prepared in the microwave so that they are crisp and tasty. The NorAbsorbit microwave packaging, which has been nominated for this year’s German Packaging Award, absorbs both moisture and grease during cooking in the microwave. The food is thus cooked directly in the retail packaging, making preparation noticeably more convenient, quicker and cleaner than conventional frying in a pan.

“The moisture that develops during microwave cooking and the released grease pass through a perforated sealing layer and are absorbed and retained by the packaging’s inner layer,” explains Dr Herbert Bader, managing director of Nordenia’s development branch. “Even unbreaded foods such as bacon thus become much crispier than with conventional microwave technology.”

NorAbsorbit also has thermal insulating properties that reduce the outside temperature of the packaging after microwave cooking, making it possible to handle the bag after cooking. An additional steam venting label can be integrated to allow for especially gentle steam cooking to preserve the food’s natural flavour and vitamins. The entire surface of the pack can also be printed and include a window allowing the consumer to view the food.

“NorAbsorbit is also important from an ecological point of view,” suggests Bader. “Preparation of food in the oven consumes much more energy than in the microwave; and as the flexible NorAbsorbit packaging – which can be processed on conventional FMS systems – can replace bag-in-box susceptor packaging, material is also saved during packaging production. A portion of the microwave packaging can also be produced from renewable raw materials.”

A leading product on the compostable films scene is Innovia’s NatureFlex NVR cellulose-based material. This two-side coated, heatsealable, renewable and certified compostable film with an intermediate moisture barrier is suitable for box overwrap and individual flow wrap applications. It begins life as a natural product, wood (from managed plantations operating on good forestry principals, FSC or equivalent) and breaks down in a home compost bin (or industrial compost environment) “within a matter of weeks”. It also offers advantages for packaging and converting such as inherent deadfold and anti-static properties, high gloss and transparency, resistance to grease and oil, good barrier to gases, aromas and mineral oils and a wide heatseal range.

Joachim Janz, Innovia’s sales account manager, says: “Our customers can tick various boxes easily relating to product safety and the objective of using a sustainable packaging material. NatureFlex films offer both suitable aroma barrier and a functional barrier to mineral oil migration which has been scientifically confirmed to last for five years.

“Mineral oil barrier is especially welcome in the tea industry, where recent German publications highlight that various tea products have weaknesses concerning mineral oil protection.”

This was one of the reasons why NatureFlex was chosen recently to pack the range of organic teas marketed by German company Lebensbaum. Introducing packaging materials based on renewable resources also fitted neatly with Lebensbaum’s sustainability strategy.

In Switzerland, manufacturer of customised labels for the food, pharma and construction industries Orimia has chosen a highly chemically resistant polyester (PET) film from Lintec for a specialist project at a Swiss research laboratory. Hans Keller, managing director at Orimia, explains: “The required labelstock for identifying medical bottles had to offer superior chemical resistance, as the labels would be exposed to a variety of harsh chemicals, including acetone. Lintec’s Durafol product won the laboratory’s confidence due to its high performance coating with outstanding resistance to chemicals, humidity, elevated temperatures and UV. We’ve now been asked to supply 100,000 labels.”

Available in matt white, matt silver and matt clear, Durafol is a thermal transfer printable polyester said to resist repeated harsh chemical exposure without compromising adhesion, coating or print.

Emerging intelligence

In the USA, printed electronics specialist Thinfilm and Bemis are jointly to develop a flexible sensing platform for the packaging market: “a new category of packaging that can collect and wirelessly communicate sensor information, for use by leading food, consumer products and healthcare companies worldwide”. Thinfilm already has technology partnerships to develop an inexpensive, integrated time-temperature sensor for use in monitoring perishable goods and pharmaceuticals.

The new agreement will extend this work to create a customisable sensor platform that Bemis will then tailor to customers’ individual requirements. When used in packaged perishable products, the Intelligent Packaging Platform can be adapted to monitor and record key physical properties and environmental data.

“Intelligent packaging is an emerging technology with many potential intersections with our flexible packaging and pressure-sensitive materials business segments,” says Bemis president and CEO Henry Theisen. “Our agreement with Thinfilm represents an investment in a technology that could eventually make printed electronics a component of every package we manufacture.”

“Innovative solutions that simply could not be manufactured before are soon to be delivered,” enthuses Davor Sutija, Thinfilm’s CEO. “Our partnership with Bemis will lead to new categories and types of packaging that will bring intelligence to everyday lives of millions of people worldwide.” The Bemis Intelligent Packaging Platform is expected to be commercially available in 2014.

Technical savings

Another US company, UniPixel, has developed a low cost, transparent conductive film manufactured using a roll to roll process by micro and nano-embossing a UV curable coating.

Today’s electronic devices may be thought of as a complex stack of layers or films, and one of the most critical functions of those films is that of conductivity.

The dominant technology used for transparent conductive films is thin films of ITO (Indium Tin Oxide). However, ITO has several major problems, such as cost, future availability and brittleness.

UniPixel’s novel solution is to form a template using a UV curable material to produce a complex grid that serves as a pattern for conductive inks. The resulting ink pattern at 5 to 10 micron line width is said to produce a transparent, conductive film with excellent flexibility and conductive properties. This enables the conductive grid to be produced at low cost using roll to roll coating equipment – a significant advantage – with excellent conductivity, and transparency, and greater size, the company says.

UniPixel has also taken the concept of micro or nano-embossing UV curable films to develop anti-fingerprint films and security films, as well as a high performance, “hard but flexible” coating as a protective layer for touchscreens.

Leading manufacturer of polyester films for packaging applications Flex Films is making significant progress in its corporate mission to set up strategically-located, global scale manufacturing facilities as close as possible to major packaging film markets. In June 2012, a new 8.7m wide polyester film line was commissioned at Wrzesnia in Poland, capable of producing 36,000 tonnes/year of films.

Another 8.7m line is scheduled to come on stream in the US during the last quarter of 2012. Flex Films now has lines running in India, Dubai, Mexico, Egypt and Poland; together, they are said to account for more than 90% of global packaging requirements.

Flex Films CEO Pradeep Tyle says: “We tell customers not tie their money up in film inventories and warehousing, as we commit to despatching freshly manufactured film supplies within seven days of receipt of their orders. Freshly manufactured films bring with them much better functional properties that make them better suited for conversion and packaging applications.”

Part of the US$1.2 billion India-based Uflex Group, Flex Films is “totally focused on the flexible packaging business”, with products including plain, coated and metallised films, flexible laminates, pouches/bags, and holographic materials.

Recent developments include rPET films incorporating up to 30% recyclate PET resin sourced from post-consumer waste such as used PET bottles; a static-free grade of PET film for high speed twist wrapping, said to be more eco-friendly and deliver very much higher wrapping speeds than the conventional PVC films it replaces; and a PET film that can be directly extrusion coated or extrusion laminated without priming. All of these films are FDA and EU approved for direct food contact.

Amcor has added two new Ceramis transparent high barrier OPP films to its range. The new CPP 004 and CPP 005 SiOx coated 18 micron films promise “ultra-high” barrier levels for both oxygen gas transmission and water vapour transmission. They can be applied to a wide range of end products which do not require pasteurisation or sterilisation. CPP 004 is sealable on one side, whereas CPP 005 is designed for two-side converting. Both products are said to combine high transparency with the required mechanical properties of a laminate.

Thanks to a new base film, Amcor has also “significantly improved” the technical properties of its Ceramis PLA film. The new CPN 003 grade is available in a gauge of 20 micron and fulfils the requirements of the DIN EN 13432 standard, certified by DIN CERTCO and said to be fully compostable.

Multilayer trend

On the film production front, leading machinery supplier Reifenhäuser Kiefel Extrusion notes a clear trend towards high barrier and multilayer films. “Moving to a higher number of layers in multilayer film production improves flexibility and helps save raw material costs,” the company observes. “The rising demand for 5 to 7 and 9-layer blown film lines, proves that more and more manufacturers want to take advantage of these benefits.”

Although the purchase of a multilayer line requires higher initial investment costs, payback can be fast due to a possible reduction or substitution of the raw materials used: intelligent material combinations in 7-layer film production enable thinner individual layers to be run than in 5-layer structures. This can result in significant savings in production costs, it is claimed, as the raw materials are the largest cost factor in film production. Film properties not only remain unchanged with less material consumed, but can normally even be improved due to new combinations of layers and raw materials.

In addition to cost reduction, the high quality of multilayer and high barrier films offers producers the opportunity to enter new markets that cannot be served with mono or 3-layer films. Specific properties of multilayer films are essential for the protection of packaged food products. Reifenhäuser Kiefel Extrusion says that its modular Evolution range of extruders can be used to produce both, and complex technical films and food packaging with high grade barrier properties.

Polished performer

Battenfeld-Cincinnati claims its new Multi-Touch polishing stack will enable film producers to achieve a high degree of transparency, excellent flatness and an extremely even film thickness on materials such as PS, PET and PP, EVA or laminated products.

The Multi-Touch comprises a 2-roll polishing stack for preliminary calibration, followed by three, five or seven rolls for final calibration. The first two rolls come with a large diameter to minimise deflection. They are followed by smaller rolls to achieve flat, stress-free film and sheet. In contrast to the well-established, conventional 3-roll polishing stacks, the Multi-Touch is claimed to provide absolutely even, consistent contact between the film and the rolls even at maximum line speeds, which ensures optimal cooling of both sides of the film.

The first Multi-Touch has been running since autumn 2011 at a major German film producer who is said to be “enthusiastic” about it.