Oriented profile fibers

Oriented non-circular fibers comprising elongate spun fibers having a non-circular cross-section defined by:

• SRF=X.sub.orf /X.sub.fib <1.3
• where X is defined as the ratio of the fiber or orifice cross-sectional area (A) to the square of the fiber or orifice diameter (D), and
• SRF2=Y.sub.orf /Y.sub.fib <3.5
• for fibers formed from dies where Y.sub.orf /4.pi.>20, or
• SRF2=Y.sub.orf /Y.sub.fib <2.0
• for fibers formed from dies where Y.sub.orf /4.pi.<20, where Y is defined as the ratio of the fiber or orifice perimeter squared to the fiber or orifice cross-sectional area, said fibers formed by a process comprising the steps of:
• heating at least a portion of a contained flow path formed by a conduit means, said flow path defining conduit means having at least one thermoplastic material inlet and at least one thermoplastic material outlet,
• providing a non-circular profiled orifice at said at least one thermoplastic material outlet which orifice is in communication with a second fluid region,
• passing a thermoplastic material through said heated portion of said contained flow path such as to heat said material to a temperature about 10.degree.-90.degree. C. above its crystalline phase transition temperature or minimum flow viscosity to form a fluid thermoplastic stream,
• forming said fluid thermoplastic stream into a profiled stream substantially corresponding to the shape of said orifice while passing said stream from said flow path into said second fluid region,
• orienting said profiled stream in said second fluid region by drawing said profiled stream at a draw down rate of at least 10 while cooling said profiled stream with a quenching fluid in said second fluid region, wherein a fiber is formed having a profile substantially identical to that of said profiled thermoplastic stream.