Patent ID: 7476352

Claim:
A method of making a polymeric fiber, the method comprising: passing a polymer melt stream through an orifice located within a die, wherein the orifice comprises an entrance, an exit and an interior surface extending from the entrance to the exit, wherein the orifice comprises a semi-hyperbolic converging orifice, and wherein the polymer melt stream enters the orifice at the entrance and leaves the orifice at the exit; delivering a lubricant stream comprising a lubricant to the orifice separately from the polymer melt stream, said lubricant stream having a viscosity, wherein the lubricant stream is introduced at a location at the entrance of the orifice and wherein the viscosity of the lubricant stream is such that the lubricant stream forms a layer around a perimeter of the polymer melt stream when the polymer melt stream is in the orifice; and collecting a fiber comprising the polymer melt stream after the polymer melt stream leaves the exit of the orifice.