Abstract
In melt spinning process of polypropylene hollow fiber, the effects of spinning conditions such as flow rate, die temperature, take-up speed on the diameter and hollowness of spun fibers were studied. For the spinneret of melt spinning, segmented arc type was used and the effect of air flow rate which dragged in hollow part of fibers was considered by taking account of extrudate swell from this type of spinneret. Experimental results show that when the flow rate, die temperature and take-up speed increase, the hollowness of spun fibers decreases. The development of hollow fiber characteristic along the spinline was investigated by the simulation of fiber forming process in which boundary conditions were determined experimentally. In this simulation hollowness of fiber along the spinline decreased and this trends were verified by experiment. In the simulation of spinning of hollow fibers, the freezing point distance is shorter than that of solid fibers and stress at freezing point is larger than that of solid fibers under the same spinning conditions.