ADDITIVES | RECYCLING
Ceranovus PN20 can be used in recycled HDPE compounds, again at a 2% loading. “Keeping screw speed and throughput constant, the extruder back pressure and energy consumption was decreased by 10% and 20%, respectively,” Hedesiu says. “Alternatively, extruder throughput was increased by 27% when average hourly energy consumption was maintained. All physical properties were maintained, with slight improvements in Izod impact and elongation at break.”
Above: Avient’s ReJoin masterbatches are made using post consumer recycled carrier resins
help to preserve critical mechanical properties such as impact resistance, elongation and tensile strength. The company also highlights its Rejoin PCR masterbatch for polyolefin packaging applications. Made with post-consumer recycled polyolefin and polyester as a carrier resin, it can enable a bottle or part to be manufactured from 100% PCR. “It’s an exciting development because, until now, master- batch has generally been made using virgin material as a carrier resin,” says a spokesperson. Canada’s GreenMantra Technologies claims to be the first to upcycle post-consumer and post- industrial recycled plastics into specialty wax processing aids for compounds suitable for various non-food applications. These include buckets, crates, pallets, automotive parts, furniture, bottles, pipes & fittings, and sheets. Marketed under the Ceranovus PN brand, the additives are said to improve processability, enable higher recycled content incorporation at equal or enhanced final product performance, enable higher filler contents, and improve finished part surface quality. According to Cristian Hedesiu, an advisor to the company, the addition of 2% Ceranovus PN55, for example, improves operational efficiency in PP compound production, “as demonstrated by significant decreases in the extruder load and back pressure.”
Recycling synergies Additives specialist Völpker Spezialprodukte has several Cevo branded products that are finding use in plastics recycling. Lutz Matthies, Head of Busi- ness Development, says they make use of the mechanisms of dispersion, stabilisation, compatibi- lisation and chemical intervention in the chemical structure of the polymer, depending on the required tasks. “The use of synergisms of the additive components used plays an important role here,” he says. “The focus of Cevo for recycling is on engineering plastics but use in the area of commodity plastics such as polyethylene has also proved successful.” Matthies highlights the company’s Cevo A-2020,
Cevo D-2050, Cevo-stab F-5510 and Cevo-master B-6000 products. The Cevo A-2020 grade is intended for use in polyamides. “Especially in the field of polyamide recycling, the repeated thermal stress on the polymer leads to chain degradation, which is reflected in a reduction of viscosity,” says Matthies. This is accompanied by a loss of mechani- cal properties, especially toughness. “Through the targeted use of Cevo A-2020 in the compounding process, the polyamide chains can be repaired, and the desired viscosity numbers (a measure of molecular weight) can be specifically set. The reactive extrusion step can also be used to counter- act degradation reactions caused by processing in general.”
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Table 1: Effect of the addition of Cevo-process A-202 on viscosity and toughness of re-compounded PA6 derived from fibres Formulation
Viscosity number ml/g
97,3% PA6-agglomerate + 0.5% CaSt + 0.2% Irgafos 168 + 2% black masterbatch
97.3% PA6-agglomerate1) + 0.5% CaSt + 0.2% Irgafos 168 + 2% black masterbatch + 0.5% Cevo-process A-2020
97.3% PA6-agglomerate1) + 0.5% CaSt + 0.2% Irgafos 168 + 2% black masterbatch + 1.0% Cevo-process A-2020
Source: Völpker Spezialprodukte 68 COMPOUNDING WORLD | October 2021
www.compoundingworld.com 120 134 145 Notched
impact strength kJ/m²
12 13 16
IMAGE: AVIENT
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