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In a polymer processing system using Spinline Heating Spinning (SHS) technique, the conven tional drawing process can be omitted. The SHS process is characterized by the presence of a heating de vice located between the spinneret point and the take-up point. Drawing was conducted in the heating zone at lower spinning tension and higher temperature in comparison with the conventional spin-draw process. Unlike the conventional drawing system, the draw ratio can be regarded as an out-put variable in this pro cess. Along with the experimental clarification of the behavior of SHS, the basic equations including the drawing behavior in the heating device were introduced for the numerical analysis. The agreement between calculated and experimental results for various take-up velocities and heating conditions were sufficient. The physical properties of fibers obtained by SHS were intermediate between those of high-speed spun fi bers and conventionally drawn fibers. The structural characteristics of SHS fibers were also clarified.

Air jet melt spinning for multifilament system was studied both theoretically and experimentally. Basic equations describing the multifilament system of air jet melt spinning were derived by considering air temperature and velocity of cooling flow surrounding the individual spinlines. Numerical computations of the fundamental equations for air jet melt spinning were carried out for various spinning conditions. Steady-state solutions obtained give the spinline cross sectional area, spinline temperature, spinning tension and spinline velocity. These are described as a function of the distance measured downward from the spinneret. Air jet melt spinning experiments were conducted for poly-(ethyleneterephthalate) (PET) having an intrinsic viscosity of 0.61. The spinning variables were changed mainly in terms of throughput, distance from spinneret point to ejector and air pressure in the ejector. Good correlations between theory and experiment were obtained for the final spinline speed or as-spun fiber denier. Further, the molecular orientation of asspun fiber can be estimated using the computed stretching speed at the ejector point. It was found that the simulation program of multifilament air jet spinning is very useful in finding the appropriate spinning conditions for the industrial spinning process and in estimating fiber properties.

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