Packaging, Shelf-Life Extension and Flexible Materials in Europe

Extended Shelf Life through Barrier Films: Broad Areas of Technological Progress Flexible barrier packaging solutions are the most resource-efficient packaging type both in terms of material consumption and the resulting extension of shelf life. Barrier layers can be easily integrated into multilayer flexible packaging formats, thereby significantly reducing the overall packaging thickness. This applies not only to liquid and dry food packaging but also to fresh food packaging such as meat, cheese and fish. For example, packaging 1 kg of fresh meat in polystyrene trays using stretch film requires approximately 40 grams of packaging material and provides a shelf life of 3-4 days. However, the same amount of meat can be placed in a completely vacuum-sealed flexible barrier package using just 3 grams of plastic packaging material, providing a shelf life of 3-4 weeks while potentially reducing food waste at the retail stage by up to 75 percent. (Denkstatt, 2017 study). Dow's high-performance sealant polymers such as SURLYN™, AFFINITY™ and adhesive layer polymers such as BYNEL® and AMPLIFY™ TY contribute significantly to the success of these packaging types. (LCA study available). The reason for the excellent performance of low-temperature sealant materials such as SURLYN™ is that they tightly coat the product and create a secondary sealant layer, keeping the meat's liquid inside the product, preventing it from becoming a bacterial growth area, thus eliminating the reasons that shorten the product's shelf life. The same applies to fish, lamb or other perishable products. In the food and liquid products sector, other examples can be found where packages that extend shelf life on the one hand while reducing food waste on the other are very efficient in small-quantity packaging. Very large packages can easily lead to such waste. Replacing rigid packages with lighter, smaller-volume alternatives that use resources more efficiently can produce important results. Today, flexible packages such as stand-up pouches (SUP) are designed in recyclable form from single-material structures preferably containing PE or PP, using a high-performance sealant layer for more efficient packaging processes. Packages may optionally contain a barrier layer or barrier coating to enhance food protection and a heat-resistant coating to meet the demands of the production process. Dow manufactures various solutions containing machine-direction-oriented (MDO) rigid PE, bidirectionally stretched heat-resistant coating PE (BOPE), OPULUX™ HGT with high-performance sealant layers such as SURLYN™, AFFINITY™, VERSIFY™ and ELITE™. A third example is dual-compartment pouches where products that cannot be transported in mixture form are packaged separately. For example, due to low shelf life, packaging the product as a mixture is not possible. However, packaging water and dry food separately and mixing them immediately before consumption extends shelf life from 1 day to months. When Dow's SURLYN™ resin is combined with other structural components such as INNATE™ resins for strength and hardness, it can provide excellent functionality to such dual-compartment bags. The fourth example is portion-wise packaging rather than bulk packaging. Portion-wise packaging is made possible with peelable packaging solutions such as APPEEL™ resins, which allow one section of the package to be opened without touching the rest of the package. This solution allows only a portion of the food in the package to be consumed while continuing to protect the remainder. How are These Technologies Developing in the European Market? The prevalence of vacuum packaging for fresh meat varies by country. This difference is often due to consumers preferring printed packages (which are more difficult to recycle compared to transparent, unprinted packages). It can also stem from retailers lacking experience with such resource efficiency and low-cost packaging. Some countries such as the United Kingdom, Switzerland and Germany are clearly leading these formats. Some other countries such as Spain, Italy and France are either not yet participating in this process or are slow to transition to this more efficient vacuum packaging process. Stand-up pouches, whether with or without oxygen barrier layers, are finding their place in various market segments globally. Today, driven by brand owners and retailers, intensive work is being done to design more recyclable varieties to adapt to the circular economy. This redesign is very important because in the past such flexible packages were primarily designed for functionality and processability, becoming complex structures that did not account for easy recycling. Developments in new single-material PE or PP-based technologies that extend food shelf life present a very strong value proposition for the packaging market. While dual-compartment bags create strong value in some regions, they are mostly a niche area. We have assisted in developing certain applications in South Europe and Africa where clean water to be mixed with food is not always readily available. Providing Advanced Functionality While Considering Circularity Strategies Of course, the use of flexible barrier packaging leads to the use of multilayer structures because many different components are combined in a film. These components are usually incompatible with each other during the recycling process. Most people think that multilayer structures used in flexible packaging are by definition non-recyclable and therefore not aligned with circular economy thinking. However, this is not entirely correct. This is why the flexible packaging industry (CEFLEX and other sector value chain organizations) is working intensively on design rules to facilitate the recyclability of flexible packaging forms. First and foremost, the films must reach an existing recycling line such as PE, PP or PET. For this to happen, sorting systems need to identify the films as PE, PP or PET. After that, the other components in the multilayer structure must be compatible with this recycling line or have no significant negative impact on the process. Generally, the oxygen barrier component, whether EVOH, PA or PET, will provide only limited compatibility with PE or PP – the solution to this is to minimize the amount of these components already present in packaging production or improve the distribution of incompatible components and add special "compatibilizer" resins to minimize the negative effects on recycled resin properties. Additionally, certain components such as pigments, paper, PVDC (polyvinylidene chloride) etc. should be avoided. Returning to the example of the vacuum bags for fresh meat packaging above, these can be produced with newly developed manufacturing processes that yield multilayer barrier films consisting only of thermoplastic components and typically unprinted and consequently recyclable in the PE recycling stream. However, unprinted packaging is usually less appealing to consumers. In stand-up pouches, the path to recyclable design lies in combining oriented PE or PP with a special ethylene copolymer or propylene copolymer sealant layer. Oriented films provide rigidity, high gloss and protection, while the sealant layer provides high-speed packaging capability. These together can be recycled in PE or PP recycling streams. Dr. Karlheinz Hausmann Research Associate Dow