MATERIALS | STRETCH & SHRINK FILM


– to ensure stable feed of difficult raw materials such as film flake. Other equipment, such as compounders, are also critical in turning waste material into recyclate – as they must be able to handle challenges such as moisture, contaminants and other polymers/gels. Optical control can be used to detect defects such as black specks, contaminants and gels. “To improve the quality of film recyclates, the


Above: Coperion says its MEGAfeed side feeder can boost recycling of plastic film


Adding PCR Veronica Colombo, senior TS&D specialist at Dow Chemical in Spain, explained how PCR can be used in secondary and tertiary packaging while maintaining performance standards – using its Revoloop recycled resins. The LDPE grades have high consistency and are


certified by RecyClass, she said. They have a range of MFIs, densities and PCR contents of 70-100%. The source of the PCR is typically from the logistics industry, she added. “We also have new HDPE and LLDPE Revoloop


grades coming soon,” she said. The LDPE grades are used in various structures including collation shrink, stretch hoods and stretch wrap. One three-layer collation shrink structure, for instance, contained a 50% core layer of Revoloop, with skin layers of LDPE and LLDPE materials; and a stretch hood film contained a core layer of Revo- loop, Elvaloy and Elite resins, with LLDPE and Dowlex skin layers. The company has also developed a five-layer,


17-micron all-PE cast film containing 30% Revoloop PCT – which can achieve higher elongation values, she said. “These mono-component structures mean


there’s no need to compromise on critical perfor- mance requirements,” she said. “It’s possible to incorporate PCR to meet PPWR legislation in collation shrink, stretch hood and stretch wrap applications.”


Quality film Patrick Trubic, a sales engineer in recycling at Coperion, talked about the challenges of maximis- ing quality in recycled film – which cause factors such as a brown, glassy or opaque appearance. He said one way to overcome this is by paying attention to techniques such as material handling


34 FILM & SHEET EXTRUSION | June 2025


whole process needs to be taken into considera- tion,” he said. “Improvement in product quality starts at the sorting step.” He cited Coperion’s MEGAfeed compounder for its high throughput rates – while the shear profile of a Coperion Twin-Screw can “significantly reduce gels and improve film quality”, he added. Different feedstocks also require different equipment, he said.


PFAS replacement Henrik Eriksson, technical product manager at Baerlocher, said that PFAS-containing additives remain a problem – but can be replaced. He said the company’s Baerolub AID technology is for use with metallocene and Ziegler-Natta LLDPE blown film applications and high molecular weight HDPE. It can clear melt fracture, suppress die lip build-up and minimise interaction with other additives – while being compliant with global food contact regulations and compatible with different printing technologies. One new product prevents melt fracture. It can be dosed as a masterbatch or neat additive and is easily integrated into NDBs or additive one-packs. Trials of Baerolub AID were carried out at Collin Lab and Pilot Solutions in Germany – using a 45mm Labline E45E single screw extruder attached to a Labline BL 600P blown


film line with 80mm monolayer die. Conditions were: a 1mm die gap; 200°C


temperature profile; 40 rpm; run rate of around 12.5 kg/hr; blow-up ratio of 3.18:1; 50-micron thickness; 4-minute extruder dwell time; and samples taken every 10 minutes. In one result, melt fracture reduction initiated faster with Baerolub AID than with standard PPA – while total elimination of melt fracture was also faster. Haze and gloss were unchanged or slightly improved compared to the fluoropolymer stand- ard, according to customer feedback. “Lab-scale methods for benchmarking fluori-


nated PPAs often fail to characterise the perfor- mance of PFAS-free PPAs,” he said. “A complete performance overlap with fluorinated PPAs must not be expected.”


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