Food safety and reduced environmental impact

The ‘Save Food’ initiative estimates that approximately 50% per year of the food produced for human consumption goes bad before it reaches the consumer. This intolerable situation can easily be improved by using proper packaging. Especially in third world nations, the food protection against contamination could be drastically improved.

In highly developed countries, as well as in emerging markets, the requirements are different. Due to demographic changes and increasing living standards, packaging must implement more functions than just protecting the goods. The materials must meet various other demands, eg, marketing (design as a tool for differentiation) or convenience (easy to open, re-closable, microwavable). To fulfil these challenging requirements, flexible plastics packaging is one of the preferred materials.

It is characterised by excellent mechanical properties, impermeability to moisture and gas, high resistance to oils, fats and solvents, as well as to heat and cold, dimensional stability, scratch resistance, attractive glossy appearance, high transparency and excellent convertibility and printability.

But there is one more thing. Over the last five years, the sensitive topic of ‘sustainable use of resources’ has become more and more important all over the world.

Compared with other packaging materials, plastics films can also score in this field. Much attention has been given to a study from Denkstatt (one of the largest consulting firms in the field of sustainable development in central and eastern Europe), which found that if plastics packaging were to be substituted by other materials, the respective packaging mass would on average increase by a factor of 3.6. Life-cycle energy demand would increase by a factor of 2.2, or by 1,240 million gigajoule/year, which is equivalent to 27 tonnes of crude oil in 106 VLCC tankers – or 20 million heated homes.

Greenhouse gas emissions would increase by a factor of 2.7, or by 61 million tonnes of CO₂ equivalents/year, comparable to 21 million cars on the road or equivalent to the CO₂ emissions of Denmark (Source: Denkstatt, 2011).

Today, packaging applications often consist of more than one layer. Additional materials and energy are needed to create such a flexible packaging structure. Reducing the complexity of these packaging applications is one of the major targets for film producers, converters and brand owners. In this context ‘functional film’ is one of the key terms.

Functional films

At the technology centre of Brückner Maschinenbau, the world market leader for film stretching technology, raw material suppliers, film manufacturers and renowned institutes and universities are developing such functional films. One example is the UHB (ultra high barrier) film. Brückner’s target for the development of this metallized BOPP film was the substitution of aluminium foil in special barrier packaging applications.

The main reason for replacing thin aluminium foil with metallized BOPP ultra-high barrier films is that thin foils have a thickness of 7 micron, whereas the aluminium coatings on BOPP films are in a thickness range of 40-60nm. Considering the production process for aluminium foil, a reduction of the carbon footprint by almost 75% can be achieved.

The main characteristic of the UHB film is that a very thin, 0.5-0.8 micron surface layer of a so-called “high surface energy polymer“ results in a very strong bonding of the evaporated aluminium to the film surface, due to a very high surface energy in the range 52-56 dyne. No treatment by corona or flame is necessary to reach these surface energy values.

By using standard optical densities of about 2.3, exceptional OTR values down to 0.15 cm3/m² d bar have been obtained, the typical WVTR value is 0.2g/m² d. As the high surface energy polymer layer can be applied in thicknesses clearly below 1 micron, cost-efficient production is possible.

Such developments will meet the challenging demands of the packaging industry and consumers regarding environmental protection and sustainability. Brückner’s strategy has always been to operate its own technology centre for process and technological developments – focusing more and more on effective solutions for an environmentally-friendly production of plastics packaging.

Besides film developments, Brückner has also been optimising the potential for achieving energy savings. Compared with 1990, the company has achieved a 30% reduction in energy consumption required for the production of oriented film – and this also means a reduction of CO₂ emissions.

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