Particulate-loaded polymer fibers and extrusion methods

Abstract

Particulate-loaded polymer fibers along with methods and systems for extruding polymeric fibers are disclosed. The particulate-loaded polymer fibers have a fiber body that includes a polymeric binder with a plurality of particles distributed within the polymeric binder. Some of the particles are completely encapsulated within the polymeric binder and others may be embedded such that they are partially exposed on the outer surface of the fiber body. The polymers used in the fibers may be of high molecular weight and the encapsulated particles may be preferentially distributed towards the outer surfaces of the fibers.

1 . A particulate-loaded polymeric fiber comprising a fiber body that comprises a polymeric binder and a plurality of particles encapsulated within the polymeric binder, wherein the polymeric binder consists essentially of one or more polymers, and wherein the encapsulated particles comprise an encapsulated particle density, and wherein the encapsulated particle density is higher proximate an outer surface of the fiber. 
     
     
         2 . A fiber according to  claim 1 , wherein the encapsulated particle density within the outermost 20% of the volume of the fiber is two times or more the encapsulated particle density within the innermost 20% of the volume of the fiber. 
     
     
         3 . A fiber according to  claim 1 , wherein the plurality of particles consist essentially of non-polymeric particles. 
     
     
         4 . A fiber according to  claim 1 , wherein the plurality of particles have a maximum size of 100 micrometers or less. 
     
     
         5 . A fiber according to  claim 1 , wherein all of the one or more polymers comprise a melt flow index of 30 or less measured at the conditions specified for the one or more polymers. 
     
     
         6 . A fiber according to  claim 1 , wherein all of the one or more polymers comprise a melt flow index of 10 or less measured at the conditions specified for the one or more polymers. 
     
     
         7 . A fiber according to  claim 1 , wherein all of the one or more polymers comprise a melt flow index of 1 or less measured at the conditions specified for the one or more polymers. 
     
     
         8 . A fiber according to  claim 1 , wherein all of the one or more polymers comprise a melt flow index of 0.1 or less measured at the conditions specified for the polymers. 
     
     
         9 . A fiber according to  claim 1 , wherein the one or more polymers are semi-crystalline polymers. 
     
     
         10 . A fiber according to  claim 9 , wherein the semi-crystalline polymers are nylon. 
     
     
         11 . A particulate-loaded polymeric fiber comprising:
 a fiber body comprising one or more polymers, and wherein all of the one or more polymers comprise a melt flow index of 10 or less measured at the conditions specified for the one or more polymers; and   a first plurality of particles encapsulated within the fiber body and a second plurality of particles embedded in an outer surface of the fiber body, wherein the encapsulated first plurality of particles comprise an encapsulated particle density, and wherein the encapsulated particle density of the first plurality of particles is highest proximate an outer surface of the fiber.   
     
     
         12 . A fiber according to  claim 11 , wherein the encapsulated particle density of the first plurality of particles within the outermost 20% of the volume of the fiber is two times or more the encapsulated particle density of the first plurality of particles within the innermost 20% of the volume of the fiber. 
     
     
         13 . A fiber according to  claim 11 , wherein the first plurality of particles and the second plurality of particles consist essentially of non-polymeric particles. 
     
     
         14 . A fiber according to  claim 11 , wherein the first plurality of particles and the second plurality of particles have a maximum size of 100 micrometers or less. 
     
     
         15 . A fiber according to  claim 11 , wherein all of the one or more polymers comprise a melt flow index of 30 or less measured at the conditions specified for the one or more polymers. 
     
     
         16 . A fiber according to  claim 11 , wherein all of the one or more polymers comprise a melt flow index of 10 or less measured at the conditions specified for the one or more polymers. 
     
     
         17 . A fiber according to  claim 11 , wherein all of the one or more polymers comprise a melt flow index of 1 or less measured at the conditions specified for the one or more polymers. 
     
     
         18 . A fiber according to  claim 11 , wherein all of the one or more polymers comprise a melt flow index of 0.1 or less measured at the conditions specified for the polymers. 
     
     
         19 . A fiber according to  claim 11 , wherein the one or more polymers are semi-crystalline polymers. 
     
     
         20 . A fiber according to  claim 19 , wherein the semi-crystalline polymers are nylon. 
     
     
         21 . A method of making a particulate-loaded polymeric fiber, the method comprising:
 entraining a plurality of particles within a polymer melt stream;   passing the polymer melt stream with the plurality of particles entrained therein 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 lubricant to the orifice separately from the polymer melt stream, wherein the lubricant is introduced at the entrance of the orifice; and   collecting the particulate-loaded polymeric fiber comprising the polymer melt stream and a plurality of particles encapsulated within the polymer melt stream, wherein the encapsulated particles comprise an encapsulated particle density within the fiber, and wherein the encapsulated particle density is higher proximate an outer surface of the fiber.   
     
     
         22 . A method according to  claim 21 , wherein the encapsulated particle density within the outermost 20% of the volume of the fiber is two times or more the encapsulated particle density within the innermost 20% of the volume of the fiber. 
     
     
         23 . A method according to  claim 21 , wherein the plurality of particles consist essentially of non-polymeric particles. 
     
     
         24 . A method according to  claim 21 , wherein the polymer melt stream comprises one or more polymers, and wherein all of the one or more polymers comprise a melt flow index of 30 or less measured at the conditions specified for the one or more polymers. 
     
     
         25 . A method according to  claim 21 , wherein the polymer melt stream comprises one or more polymers, and wherein all of the one or more polymers comprise a melt flow index of 10 or less measured at the conditions specified for the one or more polymers. 
     
     
         26 . A method according to  claim 21 , the polymer melt stream comprises one or more polymers, and wherein all of the one or more polymers comprise a melt flow index of 1 or less measured at the conditions specified for the one or more polymers. 
     
     
         27 . A method according to  claim 21 , wherein all of the one or more polymers comprise a melt flow index of 0.1 or less measured at the conditions specified for the polymers. 
     
     
         28 . A method according to  claim 21 , wherein the polymer melt stream consists essentially of one polymer with a melt flow index of 30 or less measured at the conditions specified for the one or more polymers. 
     
     
         29 . A method according to  claim 21 , wherein the polymer melt stream consists essentially of one polymer with a melt flow index of 10 or less measured at the conditions specified for the one or more polymers. 
     
     
         30 . A method according to  claim 21 , wherein the polymer melt stream consists essentially of one polymer with a melt flow index of 1 or less measured at the conditions specified for the polymer. 
     
     
         31 . A method according to  claim 21 , wherein the polymer melt stream consists essentially of one polymer with a melt flow index of 0.1 or less measured at the conditions specified for the polymer. 
     
     
         32 . A method according to  claim 21 , wherein the polymer melt stream consists essentially of one or more semi-crystalline polymers. 
     
     
         33 . A method according to  claim 33 , wherein the semi-crystalline polymers are nylon. 
     
     
         34 . A method according to  claim 21 , wherein the polymer melt stream with the plurality of particles entrained therein is delivered to the entrance of the orifice through an opening that comprises a smaller cross-sectional area than the cross-sectional area of the entrance of the orifice. 
     
     
         35 . A method according to  claim 21 , wherein delivering the lubricant comprises delivering the lubricant through a continuous slot formed about the entrance of the orifice. 
     
     
         36 . A method according to  claim 21 , wherein delivering the lubricant comprises delivering the lubricant through a plurality of openings located about the entrance of the orifice. 
     
     
         37 . A method according to  claim 21 , wherein at least a portion of the lubricant evaporates from the polymer melt stream after the polymer melt stream leaves the exit of the orifice. 
     
     
         38 . A method according to  claim 21 , wherein the die comprises a plurality of orifices, and wherein the method further comprises independently delivering the lubricant to each orifice of the plurality of orifices. 
     
     
         39 . A method according to  claim 21 , wherein collecting the fiber comprises pulling the fiber, wherein the fiber is elongated during the pulling. 
     
     
         40 . A method according to  claim 21 , wherein the average temperature of the polymer melt stream passing into the entrance of the orifice is within 10 degrees Celsius or less above a melt processing temperature of the polymer melt stream. 
     
     
         41 . A method according to  claim 21 , wherein the average temperature of the polymer melt stream is at or below a melt processing temperature of the polymer melt stream before the polymer melt stream leaves the exit of the orifice.