Flexible packaging are increasingly demanded by the food industry for their quality, flexibility, barrier properties, printability, environmental sustainability, high service content
By Stefania Milanello
Packages – and not only food-grade packages – have to contain and protect, as well as face the challenges inherent consumption and sales methods, achieving safety and sustainability. New thermoplastic materials, additives, film extrusion technologies, recovery and recycling of waste and scraps are the challenges that manufacturers of flexible packaging must face. GIFLEX, the Association that brings together manufacturers of flexible packaging printed in gravure and flexography, for packaging of food, pharmaceuticals, chemicals and other industrial applications, has summarised the present and future role of flexible packaging in the brochure “Flexible packaging”. In it one reads that flexible packaging is used to contain almost half (4 out of 10) of the food products we buy. In total, statistics on the sectors that use flexible packaging are as follows: the food industry leads (90.6%), followed by household detergents, pharmaceuticals, and cosmetics (both 4.6%). The food sectors that use more flexible packaging are those of bakery goods and pasta, followed by milk and dairy products (cheese, especially in portions and pre-packaged, yoghurt, butter), as well as pre-portioned and pre-packaged meats, frozen foods, IV range products and ready meals. Packages are obtained by converting plastic films, thin materials on the basis of paper, cellulose, and thin aluminium foils used as primary and/or secondary packages which, when filled and sealed in normal conditions, have a flexible shape. Materials are selected for their properties and according to specific requirements the package must comply with, with particular attention to perishability and product shelf-life. Flexible packages are available in a variety of different shapes, types and sizes. One of the advantages is that – thanks to the possibility of being heat-sealed – these packages can be formed and sealed on automatic machines while the product is being filled into them.
High service value that benefits consumers and environment. The manufacturers of food packages strive to ensure high service content to their product, which is highly appreciated by consumers. Flexible packages perfectly respond to this requirement for different reasons. They are light in weight and small, facilitating their transport and use. The good relation between product quantity and packaging weight responds to sustainability requirements and reduction of waste. Unlike particularly fragile packages, like glass, flexible packages are unbreakable, ruling out the risk of breakage, cuts or injuries in case they are dropped. Furthermore this packagin provides for easy and space-saving storage: in fact, if the product is not entirely consumed, the flexible package reduces its volume by adapting to the product. Re-sealable packaging by means of adhesive tabs or special zippers is another plus factor of the high service content of flexible packages. Food does not need to be transferred to other containers, and the package can be used until the end of the product life. The variety of shapes these packages can take allows producing and distributing packages containing small portions, cut according to consumers’ needs, avoiding food wastes: an issue that is often neglected by consumers. According to Food Wastage Footprint: Impacts on Natural resources, FAO 2013, the environmental impact of food wastage per year involves 250,000 billion litres of water, 1.4 billion hectares of land, and 3.3 billion tonnes of greenhouse gas. Various studies show that packaging disposal impacts less on the environment than food wastage. Not only, it is now recognized that the environmental impact of packaging, irrespective of its recyclability, is lower than that caused by food production. This means that packaging is one of the basic tools in combating food waste, thanks to its containment function at each phase of the supply chain, for the preservation of food quality and safety.
Challenge for greater environmental sustainability. Consumers increasingly pay attention to environmental sustainability. Flexible packaging is one of the most eco-sustainable ones. In particular, their light weight makes them more sustainable compared to other types of packages, because they involve less energy and natural resources consumption compared to any other packaging system with the same functions, with relevant lower greenhouse gas emissions. Their light weight facilitates transportation and storage, while reducing disposal operations when the packaging turns to waste at the end of its life. The result is smaller environmental footprint, under the same conditions of use, compared to alternative, even recyclable, packages.
Cutting edge technologies. The manufacturers of flexible packages are trying to find new solutions for the reduction of thickness while maintaining the same performance, and offering more service with easy opening and closing functions, breathability, and product cooking (even with microwave). Furthermore, companies are working to obtain a flexible plastic film structure that can withstand hot-filling or pasteurization, suitable for filling on high-speed filling lines. Examples are stand-up pouches ensuring good print quality and suitable for easy-open applications (tear-off, laser scoring), offering high thermal and mechanical resistance. Flexible packaging materials for meat, sausages and cheese must guarantee barrier properties to ensure long-term maintenance and protection of the packed product. To this purpose co-extruded and laminated films, with specific thermoforming properties, a wide range of sealability, gas barrier and puncture resistance are used. The film can be pasteurizable and sterilized, peelable and non-peelable, rigid or semi-rigid, suitable for packaging machines microwaveable and suitable for horizontal, vertical and thermo-forming. For the packaging of snacks and baked goods, films ensuring high seal resistance are used. The film can be metallized or non metallized, with barrier and suitable for modified atmosphere packaging. High resistance to low temperatures is required for the flexible packaging used for frozen products. For packaging coffee, extremely flexible packaging materials such as high-barrier metallized polypropylene are used, with values close to those of aluminium. As for the materials, nano-composite coatings for flexible packages are under study. The aim is to obtain flexible packaging with high oxygen barrier and mechanical properties by using nano-composites. Flexible packaging materials are often composites. Great attention is devoted to the glues suitable for lamination. There are polyurethane adhesives, with or without solvent; when extruded in the polyethylene film, hot-melt adhesives allowing the production of resealable packages, increasingly in demand for packaging a variety of foodstuffs. There are adhesives that can be applied at low temperatures, or waterborne polyurethane adhesives, which show interesting physical properties along with increased sustainability values. Regarding the cutting of flexible films, one of the most innovative solutions concerns macro- and micro-perforations of single or multi-layered films made of different materials (including PE, PET, PP, Nylon, PTFE) with laser systems ensuring high cutting quality. Laser provides very precise selective material removal, and accurate perforating capability (100 micron), ensuring repeatability of the process. Furthermore, the all-digital process allows a rapid work change and significant reduction of downtime and costs.