Patent ID: 6719935
Filing Date: 2004-04-13
Classification: B29C,B29K

Abstract:
A continuous process for forming a thermoplastic polymer extrudate having a predetermined cross-section, comprising:extruding the extrudate at a controlled rate from an extruder at a temperature above its melting point and forming said cross-section; cooling the extrudate by passing the extrudate through a cooling bath to cool the core of the cross-section to below the glass transition temperature of the thermoplastic polymer; passing the extrudate through a first puller driven at a controlled speed; passing the extrudate through a second puller driven at a faster speed than the first puller to put the extrusion in tension between said first and second pullers; heating the extrudate between said first and second pullers; and releasing the tension on the extrudate after said second puller and prior to allowing the extrudate to cool to room temperature.