CO-EXTRUSION OF RHEOLOGICALLY MISMATCHED POLYMERS

摘要

Traditionally, the rheological properties, including, for example, the viscosities, of two or more polymers that are to be co-extruded must be well matched in order to obtain acceptable multilayer structures. This limitation severely narrows the processing window for such co-extrusions as well as the combinations of polymers that can be used in such co-extrusions. The technology disclosed herein removes these limitations and allows for the co-extrusion of a wider variety of combinations of polymers, even when the rheological properties of the polymers to be used are significantly different, while still providing acceptable multilayer structures. Stated another way, the technology disclosed herein improves the multilayer structures that can be obtained when processing two or more polymer materials with significantly different rheological properties via layer-multiplying co-extrusion.

主权项

1. A polymer extrudate comprising a plurality of extruded polymer layers comprising a plurality of alternating layers of at least first polymer material having a first set of rheological properties and a second polymer material having a second set of rheological properties different than the first set of rheological properties;
wherein the at least one of the first polymer material and the second polymer material comprises an external lubricant and wherein the first and second sets of rheological properties comprise one or more of the following properties (a) the dynamic moduli, as measured by a rotation rheometer; and (b) the shear viscosity, as measured by a capillary rheometer.