EXTRUSION METHODS AND APPARATUS AND STRUCTURES PRODUCED THEREWITH

摘要

Methods and apparatus for reducing the impact of a higher temperature polymeric melt stream element on a lower temperature polymeric melt stream element, and vice versa. The methods comprise supercooling the hotter melt stream element, exposing one or more melt stream elements to an undesirable thermal condition for a limited period of time, and/or using one or more layers as a heat sink. The apparatus is provided by a modified die in which one of the melt stream elements having the disparate temperatures traverses the die in a foreshortened path in the direction of extrusion of the extrudate.