Kida Tsukasa, Ohara Masatoshi, Inamori Keigo, Nagasawa Shogo, Kihara Shin-Ichi, Taki Kentaro
Department of Natural System, Graduate School of Natural Science, Kanazawa University, Kanazawa 920-1192, Japan.
Shibaura Machine, Numazu 410-8510, Japan.
Polymers (Basel). 2023 Feb 24;15(5):1140. doi: 10.3390/polym15051140.
The plastication of pellets in a co-rotating twin-screw extruder is a significant concern for product homogeneity and stability in the plastic industry. We developed a sensing technology for pellet plastication in a plastication and melting zone in a self-wiping co-rotating twin-screw extruder. The collapse of the solid part of the pellets emits an elastic wave as an acoustic emission (AE) that is measured on the kneading section of the twin-screw extruder using homo polypropylene pellets. The recorded power of the AE signal was used as an indicator of the molten volume fraction (MVF) in the range of zero (fully solid) to unity (fully melted). MVF decreased with increasing feed rate monotonically in the range of 2-9 kg/h at a screw rotation speed of 150 rotations per minute (rpm) because of the reduction in the residence time of pellets in the extruder. However, the increase in feed rate from 9 to 23 kg/h at 150 rpm resulted in an increase in the MVF as the friction and compaction of pellets caused their melting. The AE sensor could elucidate the pellet's plastication phenomena caused by friction, compaction of pellets, and melt removal in the twin-screw extruder.
在同向旋转双螺杆挤出机中，粒料的塑化对于塑料工业中产品的均匀性和稳定性而言是一个重大问题。我们开发了一种用于自清洁同向旋转双螺杆挤出机的塑化和熔化区域中粒料塑化的传感技术。粒料固体部分的塌缩会发出弹性波，作为声发射（AE），使用均聚聚丙烯粒料在双螺杆挤出机的捏合段对其进行测量。记录的AE信号功率被用作熔体体积分数（MVF）的指标，其范围从零（完全固体）到一（完全熔化）。在螺杆转速为每分钟150转（rpm）时，进料速率在2 - 9 kg/h范围内增加时，MVF单调下降，这是因为粒料在挤出机中的停留时间减少。然而，在150 rpm时，进料速率从9 kg/h增加到23 kg/h会导致MVF增加，因为粒料的摩擦和压实导致其熔化。AE传感器可以阐明双螺杆挤出机中由粒料的摩擦、压实和熔体排出所引起的粒料塑化现象。
