Process for making a filler reinforced thermoplastic composites having biaxially oriented components

A process for continuous production of a thermoplastic product comprising a thermoplastic compound having biaxially oriented components, comprising the steps of:

• (a) providing a thermoplastic compound comprising orientable thermoplastic polymer;
• (b) bringing the thermoplastic compound to a temperature above and including the softening point temperature of the thermoplastic compound thereby producing a softened thermoplastic compound;
• (c) extruding the softened thermoplastic compound through a die, from a die inlet to a die outlet, and an adjacent downstream cooling zone, wherein the direction from the die inlet to the die outlet defines the axial direction and wherein the circumference of the die outlet is larger than the die inlet and the bulk cross sectional area at the die outlet is less than at the die inlet;
• (d) providing a lubricant between the thermoplastic compound and the die;
• (e) constraining the softened thermoplastic compound in the die to undergo circumferential stretching flow through the die to impart circumferential orientation to at least some of the thermoplastic polymer and constraining the softened thermoplastic compound in the die to undergo axial stretching flow through the die to impart axial orientation to at least some of the thermoplastic polymer, thereby producing a softened biaxially oriented thermoplastic compound having a hollow profile having desired dimensions;
• and
• (f) cooling the thermoplastic compound having the imparted biaxial orientation in said cooling zone to a temperature below the softening point temperature of the thermoplastic compound to preserve the imparted orientation of the thermoplastic polymer while continuing to constrain the thermoplastic compound to maintain the imparted dimensions.