This paper emphasizes the importance of analyzing the residence time distribution of the polymer when designing extrusion systems and why this analysis is especially important for coextrusion systems. An analysis of the relationship between pressure drop and residence time for different die geome tries shows how the potential for problems to occur is higher for coextrusion dies. An example is presented of how changing the layer ratio of a coextrusion product can lead to long residence times which may result in poor product qual ity and possibly damage the system.
Butler, T.I. and E.W. Veazey.1990. "Coextrusion Extruder Sizing and Resin Stability", TAPPI 1990 Coextrusion Seminar Notes, pp. 55-61.
2.
Gates, P.C.1990. "Optimizing the Coextrusion Process", TAPPI 1990 Coextrusion Seminar Notes, pp. 13-15.
3.
Levenspiel, O.1972. Chemical Reaction Engineering, 2nd Ed. New York: Wiley-Interscience .
4.
Himmelblau, D.M. and K.B. Bischoff.1968. Process Analysis and Simulation : Deterministic Systems. New York: John Wiley.
5.
Halle, R.W.1989. "Thermal Stability-A Key Polymer Processing Parameter-A Comparative Study of Ethylene Copolymers", 1989 TAPPI PL&C Conference Proceedings, pp. 585-598.
6.
Butler, T.I.1989. "The Influence of Extruder Residence Time Distribution on Polymer Degradation", 1989 TAPPI PL&C Conference Proceedings , pp. 401-416.
7.
Pinto, G. and Z. Tadmor.1970. "Mixing and RTD in Melt Screw Extruders ", Polym. Eng. Sci., 10:279-288.
8.
Wolf, D. and D.H. White.1976. "Experimental Study of the RTD in Plasticating Screw Extruders", AIChE J., 22:122-131.
9.
Schott, N.R. and D.V. Saleh.1978. ''Effect of RTD on Extruded LDPE Foam ", ANTEC '78, pp. 526-539.
10.
Kemblowski, Z. and J. Sek.1981. "Residence Time Distribution in a Real Single Screw Extruder", Polym. Eng. Sci., 21:1194-1202.
11.
Stamato, H.J. and R.A. Weiss.1985. "Determination of the RTD in a Plasticating Extruder Using Ionomer Tracer", ANTEC '85 Proceedings, pp. 42-44.
12.
Perdikoulias, J., C. Tzoganakis and J. Vlachopoulos.1989. "Flow Visualization and Residence Time Distribution in Spiral Mandrel Dies", Plastics and Rubber Processing and Applications, 11(1):59-66.
13.
Nauman, E.B. and A.B. Buffham.1983. Mixing in Continuous Flow Systems. New York: John Wiley.
14.
Lin, S.H.1980. Chem. Eng. Sci., 35:1477.
15.
Fredrickson, A.G. and R.B. Bird.1958. Ind. Eng. Chem., 50:347.
16.
Vlachopoulos, J., P. Behncke and J. Vlcek.1989. "Polycad: A Finite Element Package for Polymer Process Analysis and Design", Adv. Polym. Tech., 9:147-156.
