In response to an investigation on the paths of changes in the crystallization and radial differences during the forming process of nascent fibers, in this study, we conducted numerical simulation and analyzed the changes in crystallization mechanical parameters and tensile. In response to an investigation on the paths of changes in the crystallization and radial differences during the forming process of nascent fibers, in this study, we conducted numerical simulation and analyzed the changes in crystallization mechanical parameters and tensile. Twinair fiber, developed by AsahiKASEI, is a kind of special polyester hollow fiber with a hollowness of 30%, which has high water-absorbing quality compared with the other hollow fibers. The melt spinning trials are carried out on a pilot scale melt spinning plant with different settings while a 10-hole 2c- shaped spinneret is used. A modified capillary rheometer with an aerodynamic stretching device (aspirator) is used to process various amorphous and semicrystalline fibers in a wide diameter. Experimental measurements are presented to provide phe-nomenological insight into the commercial melt blowing process. In particular, we discuss the following experimental measurements obtained at various die-collector locations: fiber diameter, fiber velocity, air velocity, fiber acceleration. In this paper the melt spinning process and technology of polypropylene fiber, polymerization conditions, preparation of polypropylene fiber by a larger variety of processes and the stress in the spinline was presented. More emphasis was given on the various polymerization processes (gas-phase and.