Method and apparatus for making submicron diameter fibers and webs there from

Abstract

A method and device for the production of polymer filaments with a diameter of less than one micron. A plurality of polymer components are extruded through a spin pack and then attenuated using gas flows which are accelerated to achieve high velocity by means of a converging, diverging nozzle. The plurality polymer components may be extruded in an islands in the sea or segmented pie configuration. As a result of the high velocity gas flow, the plural components are split apart into their individual components resulting in filaments and fibers having a diameter or minor dimension of less than one micron.

1 . A method for producing submicron fibers by melt spinning a plurality of polymers through a spinneret die in a plural component configuration to produce a multiconstituent fiber, and splitting the plural components into their individual constituents by a high velocity gas stream, said high velocity gas stream being applied to the fiber while it exits the die in a way that multiple fibers are formed from at least one of the individual constituents. 
   
   
       2 . The method of  claim 1  in which the gas stream has a velocity of between 0.7 and 1.4 times the speed of sound. 
   
   
       3 . The method of  claim 1  in which the plural component configuration is “islands in the sea” or “segmented pie”. 
   
   
       4 . The method of  claim 1  further comprising the step of applying an electrostatic charge to the filaments. 
   
   
       5 . An apparatus comprising a spin pack with distribution channels and orifices arranged such that a plurality of polymers can be coextruded in a plural component configuration, and a converging diverging gas nozzle. 
   
   
       6 . An apparatus of  claim 5  further comprising electrostatic corona discharge needles or bars. 
   
   
       7 . A method for separating the individual components of multiple component fibers comprising co-extruding the filaments through a spinneret die and splitting the plural components into their individual parts by a high velocity gas nozzle prior to complete solidification of the components.