PROCESS FOR REDUCING SURFACE ABERRATIONS

摘要

The processes and resins of the present invention allow the extrusion of polymer products, such as polymer films, that have a reduced occurrence of surface aberrations, e.g., surface melt fracture and/or haze bands and/or haze. Preferably, the polymer products produced in accordance with the present invention are substantially free of surface aberrations even when manufactured under conditions of high sheer stress such as those conditions that occur at commercial production rates. In part, the present invention provides processes for polymer extrusion wherein the resins employed are treated using heat in an atmosphere sufficient to substantially eliminate the tendency to create surface aberrations. The resins can have reduced or substantially eliminated concentrations of low molecular weight components. In some embodiments, both the polymer resins and the extruded polymer products have reduced concentrations of processing aid(s), e.g., the polymer resins and the extruded polymer products are substantially free of processing aid(s).