Studies on melt spinning. III. Flow instabilities in melt spinning: Melt fracture and draw resonance

Abstract

synopsisAn experimental study has been carried out to investigate threadline instabilities in melt spinning. Two types of melt threadline instabilities, draw resonance and melt fracture, were observed under both isothermal and nonisothermal spinning conditions. Polymers investigated were polypropylene and polystyrene. Draw resonance was observed as an increase of the takeup speed above a critical value. It was also observed that an increase in take-up speed reduces the severity of melt fracture, whereas once draw resonance OCCUR the amplitude and frequency of the pulsing thread diameter increases with the take-up speed. The phenomenon of draw resonance was investigated by taking motion pictures of the pulsing molten threadliie spun vertically downward. Furthermore, a stability analysis was carried out to explain the experimentally observed draw resonance.

Studies on melt spinning of sea-island fibers. II. Dynamics of melt spinning of polypropylene/polystyrene blend fibers

“…Fundamental equations (1-D model), describing the axial distributions of diameter, velocity, temperature, stress and structures of the fiber during melt spinning process, have been proposed by Ziabicki [1], Kase et al [2,3] and Han et al [4][5][6] in the 1960s, and further developed and modified next by other authors [7][8][9]. Recently, Kikutani et al [10] and Blanco-Rodríguez et al [11] studied the axial profiles of conditional parameters of sheath-core bi-component fibers.…”

Theory of draw resonance: Part I. Newtonian fluids

“…This draw resonance phenomenon was first observed by Christensen (1962) and Miller (1963) and has since been investigated by many researchers experimentally (for example, Bergonzoni and DiCresce, 1966;Han et al, 1972;Zeichner, 1973;Donnelly and Weinberger, 1975;Ishihara and Kase, 1976) and theoretically (for example, Kase et al, 1966;Pearson and Matovich, 1969;Gelder, 1971;Shah and Pearson, 1972;Ishihara andKase, 1975, 1976;Fisher andDenn, 1975,1976).…”

“…While various workers have reported the occurrence of draw resonance in melt spinning of a number of polymers (for example, Bergonzoni and DiCresce, 1966;Han et al, 1972;Zeichner, 1973;Donnelly and Weinberger, 1975;Ishihara and Kase, 1976), several groups conducted theoretical studies using stability analysis techniques, for example, perturbations and eigenfunction approximations.…”

Effects of Sparse Long Chain Branching on the Spinning Stability of LLDPEs

“…Draw resonance has been observed in both viscoelastic melts, such as polyethylene [1,3,9], polypropylene [3,10], polystyrene [3,9], and polyethylene terepthalate [7 to 9], and in Newtonian fluids such as silicone oil [11]. A critical draw ratio of 20.21 was calculated for a Newtonian fluid by using the solution for isothermal, Newtonian fiber spinning and a linearized stability analysis, which involves the introduction of finite (small) amplitude disturbances [5].…”