Abstract Apparatus adapted for production of endless, molecularly oriented, multifile filaments of thermoplastic polymers by extrusion of a foil or web through an elongated extrusion slit providing a foil extrusion with strand-forming segments of polygonal cross section and longitudinally extending breaking or tearing lines or zones therebetween. The extruded foil is cooled upon exit from the nozzle or immediately thereafter by surfacecooled rollers or drums or by immersion in a liquid cooler and/or by cooling air applied adjacent the nozzle. Prior to solidification, the extruded foil is longitudinally at least several times its original length. After cooling and solidification, it is again stretched between stretching roller assemblies to axially orient the polymer molecules and to tear the foil into filaments or strands along the breaking or tearing lines or zones.
An extrusion apparatus as claimed in claim 1 wherein one of said lips has a planar face, and said other lip having polygonal recesses with said narrow spaces between said recesses.
Claim 2
Dependent Claim
34 words
An extrusion apparatus as claimed in claim 1 wherein said means for cooling comprises one or more rotatable cooling cylinders adapted to draw said foil after extrusion over the cooled surfaces of said cylinders.
Claim 3
Dependent Claim
30 words
Apparatus as claimed in claim 1 wherein said lips define therebetween a zigzag or undulating space with said narrow spaces at the peaks and valleys of said zigzags or undulations.
Claim 4
Dependent Claim
34 words
Apparatus as claimed in claim 1 wherein said lips define therebetween a zigzag or undulating space with said narrow spaces provided at every other zigzag or undulation, and said strand-forming recesses at the remainder.
Claim 5
Dependent Claim
30 words
An extrusion apparatus as claimed in claim 1 wherein said lips define vertically staggered 3-4 sided polygonal strand-formIng recesses with said narrow spaces at the intersections of contiguous strand-forming recesses.
Claim 6
Dependent Claim
22 words
An extrusion apparatus as claimed in claim 1 wherein a heating duct for heating said foil is interposed between said roller assemblies.
Claim 7
Dependent Claim
31 words
An extrusion apparatus as claimed in claim 3, and nozzle means immediately contiguous to said extrusion nozzle for blowing cooling air against said foil as it is extruded from said nozzle.