Measuring nozzle for determining the extensional viscosity of polymer melts

摘要

A measuring nozzle for determining the extensional viscosity of polymer melts during their processing with a flow channel having a rectangular cross-section is provided, which has a transition section (3) between an inlet section (1) and an outlet section (2) of constant cross section, respectively, between two opposite channel walls (6 and 7) in the flow direction (8) hyperbolic tapers. In order to provide advantageous measuring conditions, it is proposed that the transition section (3) an inlet-side zone (4) in which the mutual distance between the two channel walls (7) between the two hyperbolic channel walls (6) in the flow direction (8) steadily decreases, and an adjoining outflow-side zone (5), in which two of the pairwise opposite channel walls (6, 7) parallel to each other, while the two interposed channel walls (7) in the flow direction (8) hyperbolic converge.