The system includes a ZSK 26 Mc18 twin screw extruder, four highly accurate feeders from Coperion K-Tron, as well as a water bath, an air wipe and a strand pelletizer from Coperion Pelletizing Technology. Before plastic bags and packaging were banned in Benin in July of 2018, this west African manufacturer had made its plastic films using polyethylene (PE). The new law forced the company to completely convert its production. Following a successful test and training phase at Coperion?s Stuttgart test lab, Asahel Benin Sarl. will produce biodegradable compounds in its home country with the aid of the ZSK twin screw extruder, and will then further process these on its existing blown film machinery into biodegradable bags and packaging materials. Importation, production, sale, and possession of petroleum-based plastic bags and packaging has been forbidden in Benin since 2018. Until then, Asahel Benin Sarl. had used both new PE compounds as well as recyclate for manufacturing its films that were then used predominantly in household products and in shopping bags for supermarkets.

Intensive tests at Stuttgart test lab
When the new law took effect, the blown film manufacturer had to radically alter its production. Asahel Benin Sarl. turned to the compounding experts at Coperion. From this first contact, a cooperative partnership quickly arose, as did a new corporate strategy thereafter. Asahel Benin Sarl. ordered a laboratory-scale compounding system to develop a biologically degradable compound formulation that could be used in existing blown film manufacturing facilities. The lab-scale system includes a ZSK 26 Mc18 twin screw extruder, four highly accurate powder, pellet, and liquid feeders, as well as a water bath, an air wipe and a strand pelletizer type SP 50. Before the complete system could be delivered to Benin and put into service, it was assembled and tested intensively at Coperion?s Stuttgart location in the test lab.

Sharing process engineering expertise
Throughout the entire project, Asahel Benin Sarl. could fall back on Coperion?s comprehensive, process engineering expertise, for both the mastery of the entire system?s complexity as well of as the seamless interaction of its components, and in particular relating to the twin screw extruder?s configuration. Formulations with starch content, for example, represent a particular challenge for configuring the twin screws, as the melting zone in the extrusion process must both melt biodegradable polymers and plastify non-meltable starch while adding liquid.

» Publication Date: 11/07/2019

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This project has received funding from the Bio-Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement Nº 745828