Study of coextrusion flows in polymer processsing

The analysis presented here shows how computer simulation can be used as a practical design tool to analyze coextrusion flow fields which typically occur in coextrusion process and improve the design of the equipment. Of course, the design can never be optimum for all structures because practicality dictates that several structures must be produced from one single coextrusion die. In fact because of market changes (and dies typically outlast markets), it is quite often the case that a coextrusion system ends producing a different structure than what it was originally designed for. Use of computer programs to determine stream bending or particle acceleration may lead to the understanding of the origin of flow instabilities. Layer distribution can also be predicted which may be useful in adjusting the die design or processing conditions for the production of coextruded structures with acceptable layer non-uniformities.