MATERIALS | MULTI-LAYER PACKAGING


recycled PE resin – called Syndigo – with BOPE to create a stand-up pouch with barrier properties. The pouch contains 25-45% recyclate.


Compostable film An alternative to recycling is to use compostable materials. Anthony Keyes, polymer formulations engineer at Natur-Tec, told delegates that multi- layer compostable films are a potential alternative to traditional non-recyclable structures. Using reactive extrusion, he says the company can tune both stiffness and biodegradation in its films. Combining ridid PLA elements with a flexible linker can create a material with TPE-like behaviour, he said.


Above: Nova has combined its Syndigo recycled PE with BOPE to create a


stand-up pouch with barrier properties


via thermoforming and can be deep-drawn. A second formulation, with no PA, uses three


different grades of Exceed – plus an EVOH layer – to form a barrier film. “The Exceed grades can provide an excellent contribution of thermoformability, stiffness and needle puncture performance,” said the presenters.


BOPE approach Another approach has been to increase the use of bioriented polyethylene – or BOPE – which, say suppliers, offers superior physical properties to traditional PE. “Packaging recyclability is impacting consumer


purchase decisions,” said Rob Clare, applications development specialist at Nova Chemicals. He said that key properties of high-performance,


recyclable packaging include stiffness, superior optics and heat resistance. He cited examples of packaging that uses Nova’s Surpass resin to achieve this. Orientation can help to boost stiffness, optics


and heat resistance, he said – helping it to replace PET in certain applications. He cited the example of a pouch with an all-PE design. This combines LLDPE with higher-performance grades – such as Surpass and Nova’s Astute plastomer – to create a high-barrier package. He added that improvements in converting lines have helped to turn BOPE packaging into a reality – with aspects such as more efficient cooling and sealing.


He said that oriented PE films combined with a non-oriented PE sealant web in a laminate can allow removal of nylon layers for a mono-material forming web. EVOH can be included to provide an oxygen barrier. “Different thickness BOPE films are available for shallow or deep draw applications,” he said. In one example, the company combined its


14 FILM & SHEET EXTRUSION | September 2024 “Our films can be tailored for stiffness – for


better processability,” he said. He said the company’s blown films have compa-


rable tensile strength to other blown films while being ‘stretchy’ (lower elongation) with higher stiffness (modulus) – allowing better processing on converting lines. A typical ‘non-recyclable’ film comprising PE,


EVOH and PA could potentially be replaced with a compostable structure composed of PBAT, PLA and PHA, he said. The company has carried out trials on a Davis-


Standard/Killion extruder using a 60mm diameter die – for both AB and ABA film. Results included improved seal window and strength and better heat seal performance. “A heat seal additive allowed for lower seal initia- tion temperatures,” he said. “The strength of the seals also outperformed commercial blown film formulations.” Future work will look to create multi-layer biaxially oriented films with a heat sealable skin layer.


PCR options Kevin Kelly, CEO of US-based Emerald Packaging, said that recycled materials can be effectively incorporated into multi-layer packaging – with economic benefits. The company makes packaging for fresh


produce and has incorporated up to 30% recyclate into bags for romaine lettuce, potatoes and carrots. “We offered it free of charge,” he said. He said that most ‘sustainable’ versions of multi-layer packaging will have some kind of cost premium – whether this is mono-material, com- postable of PCR-based solutions. He estimated that MDO PE had a premium of 5-20% depending on what it replaces, while both BOPE and composta- bles had a premium of 50% or more.


� www.filmandsheet.com


IMAGE: NOVA


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50