Latest developments in modification and conversion of plastic films

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  • Bio-based and biodegradable barrier layers
  • Barriers packaging using oxygen-scavengers
  • Vacuum Insulation Panels (VIP) with four times better insulation
  • High-barrier laminates for flexible plastic solar cells
  • Anti-icing coatings on large surfaces
  • Coating under atmospheric and vacuum conditions
  • Fraunhofer at #ICEEurope

The Fraunhofer Polymer Surfaces Alliance POLO will be presenting the latest developments in the modification and conversion of plastic films at the International Converting Exhibition Europe ICE in Munich.

Bio-based and biodegradable barrier layers

The Fraunhofer Institute for Silicate Research ISC will present prototypes of new packaging materials based on renewable raw materials having novel biodegradable barrier layers.The biodegradable bio-plastics that are currently used as alternatives to crude oil based plastics have their limitations. In particular, the barrier effects to moisture and gases are often inadequate. Their biodegradability is also an issue. These shortcomings are being addressed in the EU DibbioPack project (Development of Injection and blow extrusion molded BIOdegradable and multifunctional PACKages by nanotechnology).

The Fraunhofer ISC is involved in this work. The institute has developed novel biodegradable functional layers, so-called bioOrmocer layers. These can be applied as a lacquer to biodegradable films and other plastic substrates and generate functional barriers. They can keep oxygen, water vapor, aromas, and chemical substances away from the contents, or alternatively they can be employed to not allow these molecules to escape from the packaging. Up until now these requirements have not been able to be fulfilled with conventional biodegradable materials. The Fraunhofer ISC researchers use natural substances which are biodegradable and have an intrinsic barrier effect. For the novel bioOrmocer layers the researchers modified biopolymers such as cellulose and chitosan chemically such that they could be processed into lacquers. These substances are bonded by an inorganic lattice of silica which in turn has good barrier properties. This lattice does not break down in the natural degradation process as do the other natural substances. However, only a small amount of residual silica (namely sand) remains after degradation. The first experiments showed significant degradation after just six weeks for some formulations. The degradation rate can however be customized for the desired packaging properties. As part of the project, which runs to March 2016, the degradation process is now being tested in accordance with international standards.

Barriers packaging using oxygen-scavengers

The Fraunhofer IVV is developing a series of promising active barriers for packaging materials using oxygen-scavengers incorporated into a film or coating. These remove the oxygen from the headspace and almost fully protect the contents from the effect of oxygen up until the capacity of the scavenger has been exhausted. Such scavengers also exist for ethylene (fermentation gas) and for water vapor. A special case of this is purposeful generation of an ideal relative humidity in a packaging, with the ideal humidity being able to be set below the limit for microbial growth and above the level at which the food dries out.

Vacuum Insulation Panels (VIP) with four times better insulation

The Fraunhofer Institute for Process Engineering and Packaging IVV will present vacuum insulation panels (VIPs) having four times better insulation than conventional insulation materials, at equivalent space usage. VIPs consist of insulating panels vacuum-packed in an extremely gas-tight plastic barrier film. The vacuum is maintained by the surrounding film. Vacuum-deposited inorganic barrier layers are combined with organic layers. The inorganic layers consist of aluminum, or various oxides for translucent films. Both the core material and the barrier films can be manufactured using favorable-cost processes.

High-barrier laminates for flexible plastic solar cells

For flexible plastic solar cells the Fraunhofer IVV is developing high-barrier laminates on its unique lacquering and laminating plant. Advantages over conventional solar cells are their lower weight and considerably lower cost due to the fact that they are manufactured in a continuous roll-to-roll process. In order to protect the individual layers in the organic solar cells from oxygen and water vapor, the cells must be encapsulated in barrier films. These comprise a plastic substrate film and several alternating layers of inorganic materials and hybrid polymers, a development of the Fraunhofer ISC. In order to attain the target service life of 20 years, the films must be resistant to environmental effects such as UV light, high and low temperatures, and rain and also to mechanical stress.

Anti-icing coatings on large surfaces

Safety is a priority for aircraft. The effects of low temperatures in winter are known to most air travelers. Once the temperature is sub-zero, aircraft wings often have to be treated with a de-icing agent prior to take-off. Ice on wings disrupts the aerodynamics and resulting lift. However, it is not only aircraft which suffer from iced up surfaces. The rotor blades of wind turbines are also prone to icing. This causes an aerodynamic imbalance. Either the rotor blades must be heated or the turbine switched off, and both these options cost energy and money.

The Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB and partners have developed an anti-icing system for plastic surfaces within the framework of the Nanodyn project. This system involves water-repelling microstructured and nanostructured layers on which water remains a liquid, even at temperatures below zero, meaning that no ice forms. The reason: The layers do not provide the water, which wants to freeze, with crystallization nuclei on the surface and so the water remains in a supercooled state.
Even when the water freezes, the anti-icing system reduces the adhesion of the ice by more than 90 percent compared to the uncoated surface.

Coating under atmospheric and vacuum conditions

Fraunhofer FEP is a leading provider for research and development services in the field of vacuum thin-film technologies. However, for a number of applications addressed by Fraunhofer FEP coating processes under normal pressure are as well of interest. Therefore Fraunhofer FEP expands its pilot plant park by another coating plant, which works under atmospheric conditions – the atmoFlex. The new plant concept will be presented by Fraunhofer FEP at the ICE 2015 for the first time.

In vacuum processes extremely thin functional layers are applied to surfaces. Mobile phones, computer monitors or the golden coffee packaging would be unthinkable without them. However, these layers are very sensitive due to their low thickness. A new research area, which was established at the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology, examines this aspect among other things. The scientists of Fraunhofer FEP see enormous potential in the combination of coatings produced by means of vacuum and atmospheric pressure processes. The sensitive vacuum coatings can be protected by thicker coating layers. The innovative idea is that high temperatures, which usually occur during varnish drying, will be replaced by alternative drying and cross-linking procedures. Therefore, Fraunhofer FEP relies on a new roll-to-roll plant for flexible substrates (plastic or metal film, thin glass), which uses electron beams under vacuum conditions for the crosslinking of varnishes and for surface treatment – the atmoFlex.

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