Patent ID: 7666343

Claim:
A process for making a nonwoven web, comprising: a pressurized gas stream which flows within a gas passage that is confined between first and second opposing walls, wherein at least one of the opposing walls is heated; said gas passage comprising a first, upstream section into which the gas enters from a supply end, a transition region, and a second, downstream section in which the gas flows to an exit end, wherein the transition region fluidly connects the first section to the second section, and the gas passage ends at the exit end of the second section, and wherein said first section of the gas passage having a decreasing cross-sectional area from the supply end to the transition region, and said second section of the gas passage having an increasing cross-sectional area from the transition region to the exit end of the second section; at least one polymer fluid stream flowing through at least one bounded polymer passage which ends in at least one opening in at least one of said opposing walls that is heated, wherein each polymer fluid stream extrudes in the form of a film from each said opening to provide an extruded polymer film on a heated wall surface; and each extruded polymer film joining with the gas stream and the polymer film being fibrillated to form fibers comprising sub-micron diameter fibers exiting from the exit end of said second section of the gas passage.