Extrusion International 5-2020

34 Extrusion International 5/2020 EXTRUSION BLOWN FILM For the first time this model of extru- sion line was presented at K 2019 Fair where, even under the conditions of the exhibition, the company received an excellent film with a thickness of 8 microns from both low-budget biodegradable materials (Gemabio F2910) based on corn starch, and more expensive one (BASF ecovio F23B1). During the development process, Aleko Machinery specialists car- ried out a large number of tests of various types of biodegradable raw materials in order to take into ac- count all the bottlenecks that arise when using low cost biomaterial in production during the design of the extruder. However, affordable bio- degradable polymers are especially sensitive to temperature conditions and pressure inside the material cylinder, the peculiarities of melt- ing, viscous flow and crystallization of polylactide so they impose some special requirements on extrusion equipment. The advantage of this extrusion line is the special extrusion unit. Hav- ing the specially designed screw for Aleko Bio, the company used their own know-how, thanks to which the melt material flows inside the barrel extremely delicately during the ex- trusion process. Also, after calculat- ing the optimal time for the melt to stay inside, it was decided to double One of Aleko Machinery customers set a task: to invent a machine, which is able to produce a high quality film from low cost biodegradable raw material. At the time of the order, the customer had already produced such film, but on extruders designed for LDPE/ LLDPE processing. Experience has proven that, not every such machine copes well with the task due to the screw design, which is not quite adapted for biodegradable material processing. To solve the problem, the Aleko design office has developed an extrusion line “Aleko Bio”. It makes possible to produce high quality thin film from inexpensive biodegradable raw material with high capacity The Task Is: To Produce High Quality Film from Low Cost Biodegradable Raw Material When the melted material overheats, this results into burnout of thematerial followed by smoke emissions and low quality final product in the end with unsatisfactory strength characteristics, increased thickness and unattractive appearance. In addition, degradation products of biomaterials can lead to depositions in material cylinder or in die causing defected final products. Biodegradable raw material Gemabio F2910 Extrusion line Film thick- ness, mcm Tensile Strength at break, MD, MРa Tensile Strength at break, TD, MРa Elongation at break, MD, % Elongation at break, TD, % Аleko Bio (1100) 10 16,4 9,7 140 600 Other 10 10,2 6,8 100 390