Patent ID: 7695660

Claim:
A fiber-forming method comprising a) extruding filaments of fiber-forming material from an extrusion head into a gas stream; b) directing the filaments through a processing chamber in which gaseous currents apply a longitudinal stress to the filaments; c) subjecting the filaments to turbulent flow conditions after they exit the processing chamber, the temperature of the filaments being controlled so that at least some of the filaments solidify while in the turbulent field to form fibers that along their length are of uniform diameter but vary in morphology so as to provide longitudinal segments of distinctive softening characteristics during a selected autogeneous bonding operation; d) collecting the processed filaments on a collector as a nonwoven fibrous web; and e) subjecting the collected web to the selected autogenous bonding operation by heating the collected web without application of calendering pressure, some longitudinal segments softening under the conditions of the autogenous bonding operation and bonding to other adjacent fibers, and other longitudinal segments being passive during the autogenous bonding operation.