Sustainable compounding

Cope­ri­on has enabled Benin-based blown film man­u­fac­tur­er Asa­hel Benin Sarl. to pro­duce sus­tain­able, bio-based plas­tic films in the future by deliv­er­ing a com­plete com­pound­ing sys­tem and shar­ing the cor­re­spond­ing process engi­neer­ing exper­tise. 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 poly­mers and plas­ti­fy non-meltable starch while adding liq­uid. More­over, David Romar­ic Tin­k­ou, Devel­op­ment Leader of Asa­hel Benin Sarl., received com­pre­hen­sive train­ing on the com­pound­ing machine’s oper­a­tion. Thus began the devel­op­ment of a for­mu­la­tion for the nec­es­sary biopolymer.

Flexible set up

Coperion’s experts designed the com­pound­ing sys­tem for Asa­hel Benin Sarl. very flex­i­bly in order to enable max­i­mum free­dom in devel­op­ing a suit­able for­mu­la­tion. In so doing, the sys­tem can allow mate­ri­als to be added from many dif­fer­ent com­po­nents as well as inten­sive melt devolatiliza­tion. Fol­low­ing the die head with noz­zle comes a water bath for strand cool­ing, dewa­ter­ing of the strand sur­faces using an air wipe, and a strand pelletizer.

David Romar­ic Tin­k­ou is very sat­is­fied with how the project went: “It was clear quite quick­ly that we need­ed a new busi­ness strat­e­gy to keep oper­at­ing our blown film plants here in Benin. I’m very hap­py that with Cope­ri­on, I encoun­tered expe­ri­enced experts in the field of biodegrad­able com­pounds. Cope­ri­on deliv­ered not only the nec­es­sary tech­nol­o­gy, but also shared the nec­es­sary process engi­neer­ing exper­tise with me so that we can man­u­fac­ture biodegrad­able com­pounds our­selves now in Benin.”

Peter von Hoff­mann, Gen­er­al Man­ag­er Busi­ness Unit Engi­neer­ing Plas­tics & Spe­cial Appli­ca­tions at Cope­ri­on, explained: “We’re thrilled that we could sup­port Asa­hel Benin Sarl. in switch­ing over their pro­duc­tion in order to accom­plish it more sus­tain­ably. Biodegrad­able com­pounds from renew­able raw mate­ri­als unite high pro­duc­tion-tech­ni­cal demands with envi­ron­men­tal sus­tain­abil­i­ty. Par­tic­u­lar­ly for man­u­fac­tur­ers of short-lived house­hold, indus­tri­al and agri­cul­tur­al prod­ucts, these com­pounds rep­re­sent a long-term, sus­tain­able alter­na­tive to petro­le­um-based raw mate­ri­als such as PE. Typ­i­cal areas of appli­ca­tion include sin­gle-use flat­ware, trash bags and trash can lin­ers, food pack­ag­ing, shop­ping bags, drink­ing straws, and agri­cul­tur­al films.”