フッ素樹脂の押出成形におけるスーパーシアー現象―実験的考察―
Super-shear Phenomenon in Fluorocarbon Resin Extrusion Process
梁 躍・大嶋正裕・橋本伊織・香村幸夫・三上俊宏・阪本一秀
Yue Liang / Ohshima, Masahiro / Hashimoto, Iori / Komura, Yukio / Mikami, Toshihiro / Sakamoto, Kazuhide
Fluorocarbon resins are widely utilized in many industrial fields. In some processing operations, they are melted and extruded into various shapes such as tubes, solid rods and wire insulation. As is the case with other thermoplastics, fluorocarbon resins develop a rough surface, which is called melt fracture, when they are extruded above a certain critical extrusion rate. Occurrence of melt fracture defines the upper limit of the production rate. In the region of melt fracture, however, there exists a narrow region of extrusion rate in which a smooth extrudate of fluorocarbon resin can be obtained again. This is called super-shear phenomenon. To enhance productivity, it is desired to establish a practical processing technique to operate in the region where this super-shear phenomenon occurs. In this study, which is a joint university-industry study, several experiments are performed using a single screw extruder to find the important factors for realizing stable processing in the super-shear extrusion condition. We analyze the effects of die geometry-L/D ratio ; operating temperature of the extruder, and viscosity of polymer upon the super-shear phenomenon.
Key words: Extrusion process / Fluorocarbon resin / Super-shear extrusion / Melt fracture