METHOD AND DEVICE FOR DIRECT, CONTINUOUS MODIFICATION OF POLYMER MELTS

摘要

The invention relates to a method for direct, continuous modification of polymer melts with additives in the side stream and is distinguished by a very high degree of flexibility in product change-overs.

主权项

1. A method for continuous production of polyamide 6 or copolyamides which are formed from at least 70% by weight of repeat units derived from ε-caprolactam, having the following steps:
a) provision of the educts, b) formation of a prepolymer and polycondensation of the prepolymer with production of a main melt stream, c) granulation of the polymer melt, d) extraction of the polyamide granulate and e) drying, wherein a partial quantity is removed from the main melt stream produced in step b) and the partial quantity is mixed in a side stream in an extruder with a defined quantity of an additive and the modified side stream is returned to the main melt stream produced in step b) downstream before the granulation step c) and in that the aqueous extract solution formed during the extraction step d), which comprises ε-caprolactam, is concentrated and returned to step a).