Extrusion Asia Edition 2-2022

➠ PROMIX Solutions AG Technoparkstrasse 2, 8406 Winterthur, Switzerland www.promix-solutions.com 与传统产品相比，发泡电缆保护管使用的原材料减少了15%至 26%。 这节省了成本并增加了可持续性 Foamed cable protection tube is using 15 to 26 % less raw material compared to conventional products. This saves costs and adds to more sustainability 31 Extrusion Asia Edition 2/2022 Saving costs by using environmentally friendly gases Another approach to reducing costs and plastic consumption is to physically foam the pipes. Here, environmentally friendly gases such as carbon dioxide or nitrogen are injected into the plastic and mixed with it in the extruder. In the subsequent pipe extrusion process, these gases form a fine-pored foam that leads to weight reduction and thus to savings in plastic. Joint venture – working together for the best result In a joint project of the companies Hans Weber Maschinenfa- brik and Promix Solutions, the feasibility, practicality and savings potential have now been determined. For this purpose, WEBER provided a grooved barrel extruder type NE7.40 for the foamed middle layer and a grooved barrel extruder type NE5.40 for the inner and outer layers. A WEBER PKM250 3-layer pipe head was used as the die. In addition, the downstream equipment avail- able in the technical center of Hans Weber GmbH: Cooling sec- tion, haul-off and saw were used. Promix Solutions provided an N400 gas dosing station with adapted injector for precise me- tering of the nitrogen and a P1 180 melt cooler for homogeni- zation and temperature reduction of the melt. In the initial trials, Borealis' HDPE HE3490 LS was used for a DN110 x 6.3 cable protection tube and foamed with nitrogen. After production of a non-foamed reference sample, the meter- ed gas quantity was gradually increased, resulting in a weight re- duction of up to 26 % for virgin material and approx. 15 % for recycled material – based on the entire pipe. The pipe produced in this way was subsequently tested in accordance with DIN 16876 and GA KSR 2010 (Switzerland) and was able to meet all requirements. Particular attention was paid to the ring stiffness and the drop test according to DIN EN 744. Based on these po- sitive results, the test was repeated with a foamed inner layer made of recycled HDPE. This also showed good feasibility with a stable process. More sustainability through physically foamed cable conduits In view of the current supply situation for polymers and the ever increasing material prices, microcellular foaming of plastic pipes is a perfect way to save material and reduce the CO 2 footprint for the pipes. In contrast to foaming with exothermic chemical blowing agents, no SVHC (substances of very high concern) listed additives are used and an accumulation of additives via regrind recycling is also avoided. Of course, this technology can also be used for other pipe systems. In the coming months, the joint tests of WEBER and Promix will be continued to foam further pipe variants, throughputs, and other polymers with this technology. Furthermore, they are working together on a solution for physically foamed PVC ex- trudates. www.smart-extrusion.com