MATERIALS | PLASTIC POUCHES


resources such as online tools. In a pouch design, for instance, there are


Below: Berry Global has developed a number of high barrier plastic pouches


recommendations on each element. If pouches have a cap, this is typically made from PP – unlike the PE of the pouch itself, for instance. Factors such as barrier materials, laminating adhesives and inks should also be carefully considered. “Sorting behaviour is crucial,” he said. “Depend- ing on the size and weight of the closure, the packaging can be sorted as 2D/3D, PE/PP or multi-component.” As an example, analysis of laminating adhesives shows that testing of films – with techniques such as TGA – revealed variations in behaviour such as gel formation and yellowing, depending on the materials used. Recommendations included: using high-performance adhesives in order to overcome gel and speck formation; and that aromatic PU can cause yellowing. One way to address problems is to the use the


online Recyclass tool, which helps producers to assess the recyclability of a packaging design for themselves. “It gives precise indications on critical points to be improved,” said Potaufeux.


Mono material Several presenters said that using a single material in the pouch design helps to increase


recyclability. Neal Geryl, business development director


IMAGE: BERRY GLOBAL


at Berry Global, said that – under the new European PPWR law – pack- aging must be recycla- ble. This means the packaging must meet certain criteria, including: being designed for recycling; secondary materials can substitute


primary raw materials; and the packaging can be efficiently collected, sorted into defined waste streams, and recycled at scale. “Mono-PE solutions are available and here to


stay,” he said. “Implementation of these requires collaboration across the value chain.” The main technical challenges are to ensure that mono-PE packaging has the required stiffness, heat resistance and cost as traditional designs. He cited the example of how Berry’s MDO PE outer layer film range can help to do this. It is available in thicknesses of 16, 20, 25 and 35 microns for both duplex and triplex structures, in both gloss and matte finishes. Developments include PFAS-free versions, heavy-duty MDO PE –


24 FILM & SHEET EXTRUSION | July/August 2024


for more demanding applications – and sealable MDO for lap seal and other applications. He said that Berry has also developed a range of


sealants – with properties including low seal initiation temperature (SIT), with or without an EVOH or PA barrier.


PP approach Other mono-material designs are also possible. Jonathan Marshall, new product development manager at Innovia Films, described how mono- PP laminates can be used in pouches. “The continued growth in the use of pouches – and the need for increased sustainability – is driving the development of mono-material solutions,” he said. Pouches are very efficient in terms of how much


product they can protect, he said – saying that a 1kg glass jar protects 1.7kg of product – while 1kg of pouches can protect 56kg of product. Despite their advantages – especially for


recycling – mono-material pouches must maintain barrier, rigidity, sealing and puncture resistance if they are to challenge their ‘multi-material’ counter- parts. “Matching these properties using mono materi- als can be challenging,” he said. Several properties of PP make it suitable for


creating recyclable pouches, he said – including high transparency and stiffness, good moisture barrier and recyclability. This includes both cast PP and bioriented PP (BOPP). While having good dimensional stability, BOPP can also be imbued with an effective barrier using metallisation or the addition of a co-extruded EVOH layer. A retortable pouch, for instance, could be made


in a three-layer structure combining BOPP, a high barrier PP and cast PP – which could combine a mono-material design with recycled material.


Mono advantages Jorgen Kemps, lead engineer for market develop- ment at Sabic, highlighted mono-material solutions in both PE and PP. He cited thermal resistance, optical properties and toughness as important factors in selection. “The decision is driven by value-chain position


and brand owner preference,” he said. Typical PE solutions will combine PE with BOPE or MDO PE, or combine BOPE layers, he said, while PP solutions might combine CPP and BOPP, or three different BOPP layers.


Oriented PE films can enable design of recy-


cling, he said, as they increase stiffness and improve barrier properties – helping them com-


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