A flash spin pack (20) for a flash-spinning apparatus (26) is provided in which the pack includes a spin mixture inlet that communicates with a spin mixture passage that discharges through a spinning orifice (36) that opens into a slot (24) defined by two opposing faces of the body of the spin pack (20). The slot (24) is 0.25 mm to 7 mm wide proximate the spinning orifice (36) outlet, 0.25 mm to 10 mm at the slot outlet, and the distance from the orifice outlet is 1.5 mm to 40 mm. The spin pack (20) may have five or more spinning orifices (36) that each discharge into a different slot (24) so configured.
