抄録
In the spinning of acrylic fiber from the dope of copolymer of 10% conc., using NaCNS as solvent and NaCNS aqueous solution as coagulation solution, the dope column expands in an onionlike side-view immediately after extrusion.
In this experiment, the maximum diameter of extruded fiber and the distance to the maximum expansion point from spinneret holes were measured, in varying spinning velocity and the diameter of spinneret holes.
It was observed that spinning velocity has effects on the maximum diameter of extruded fiber, the distance and time to reach the maximum expansion point from spinneret holes, and that, when the velocity exceeded a certain value, the shape and the position of the onion changes depending on the tension. The critical spinning velocity was estimated as 175cm per min. in relation to the distannce to the maximum expansion point.
When the diameter of aspinneret hole is 0.09mm, the value of the maximum diameter of extruded fiber and the calculated diameter of extruded dope column are the same, and apparently no diffusion was noticed between coagulation solution and dope column. As the spinneret holes became finer, the maximum diameter became smaller than the calculated diameter of extruded dope column. This is due to the extruded dope column that attains the critical concentration of coagulation faster as the amount of NaCNS per unit length of the extruded dope column become less.
As the spinning velocity becomes larger in the non-tension spinning, the maximum diameter of extruded fiber and the distance to the maximum expansion point from spinneret holes became smaller, but, they could not become smaller than the diameter of spinneret holes. The time to reach the maximum expansion point was 10-3 sec.
