Filtered polyetherimide polymer for use as a high heat fiber material

Abstract

Various embodiments of polymer fibers comprising a high heat polymer and process for making the polymer fibers are provided. In one embodiment, synthetic polymer fibers comprise polyetherimide polymer that is substantially free of foreign particulate matter greater than about 100 microns in size. A process for producing polymer fiber includes melting polymer comprising polyetherimide to a melt temperature that ranges from about 180-500° C. to form a molten polymer; passing the polyetherimide that is substantially free of foreign particulate matter above about 100 microns in size, through a spinneret comprising a plurality of hole openings to produce a fiber bundle; and cooling the fiber bundle with a cooling medium having a temperature that ranges from about 0° C. to about 80° C.

1 . A synthetic polymer fiber comprising a polyetherimide polymer consisting essentially of polymer substantially free of foreign particulate matter above about 100 μm in size. 
     
     
         2 . A synthetic fiber according to  claim 1  substantially free of foreign particulate matter greater than 75 μm in size. 
     
     
         3 . A synthetic fiber according to  claim 1  substantially free of foreign particulate matter greater than 50 μm in size. 
     
     
         4 . A synthetic fiber according to  claim 1  substantially free of foreign particulate matter greater than 25 μm in size. 
     
     
         5 . A synthetic fiber according to  claim 1  substantially free foreign particulate matter greater than 10 μm. 
     
     
         6 . A synthetic fiber according to  claim 1  wherein the polyetherimide is substantially free of foreign particulate matter having a size greater than or equal to 85% of the diameter of the fiber. 
     
     
         7 . A synthetic fiber according to  claim 1  wherein the polyetherimide is substantially free of foreign particulate matter having a size greater than or equal to 50% of the diameter of the fiber. 
     
     
         8 . A synthetic fiber according to  claim 1  wherein foreign particulate matter having a size greater than or equal to 25% of the diameter of the fiber have been removed from the polyetherimide. 
     
     
         9 . A synthetic fiber according to  claim 8  wherein the polymer comprising polyetherimide is a filtered polymer. 
     
     
         10 . A synthetic fiber according to  claim 8  wherein the foreign particulate matter has been removed by filtering the polyetherimide polymer using at least one filter screen and wherein the at least one filter screen has screen hole sizes that are at least about 15 microns in size. 
     
     
         11 . A synthetic fiber according to  claim 8  wherein the foreign particulate matter has been removed by filtering the polyetherimide polymer using a filter screen pack of at least two screens having screen holes, and the size of the screen holes range from greater than about 10 microns to about 45 microns. 
     
     
         12 . A synthetic fiber according to  claim 8  wherein the foreign particulate matter has been removed by filtering the polyetherimide polymer using a sand filter. 
     
     
         13 . A synthetic fiber according to  claim 1  wherein foreign particulate matter having a size greater than or equal to 10% of the diameter of the fiber have been removed from the polyetherimide. 
     
     
         14 . A synthetic fiber according to  claim 1  having a denier per filament of between 0.1 and 50. 
     
     
         15 . A synthetic fiber according to  claim 1  having a denier per filament of between 1 and 20. 
     
     
         16 . A synthetic fiber according to  claim 1  having a denier per filament below 10. 
     
     
         17 . A synthetic fiber according to  claim 1  having a denier per filament of 2. 
     
     
         18 . A synthetic fiber according to  claim 1  having a denier per filament of 4. 
     
     
         19 . A synthetic fiber according to  claim 1  having a denier per filament of 6. 
     
     
         20 . A synthetic fiber according to  claim 1 , wherein the fiber has a tenacity of at least about 0.5.g/denier or greater according to ASTM 2256-97. 
     
     
         21 . A synthetic fiber according to  claim 1 , wherein the fiber has an elongation at break of at least 10% according to ASTM-02256-97. 
     
     
         22 . A process for making polymer fiber, the process comprising:
 melting a polymer comprising polyetherimide to a melt temperature that ranges from about 180° C. to about 500° C., to produce a molten polymer comprising polyetherimide;   passing polyetherimide substantially free of foreign particulate matter above about 100 μm in size, through a spinneret comprising a plurality of hole openings to produce a fiber bundle; and   cooling the fiber bundle with a cooling medium, the cooling medium having a temperature that ranges from about 0° C. to about 80° C., to produce fiber.   
     
     
         23 . The process of  claim 22 , further comprising removing foreign particulate matter from the polyetherimide prior to passing the molten polymer through the spinneret. 
     
     
         24 . The process of  claim 22 , further comprising filtering the polymer comprising polyetherimide, prior to melting the polymer. 
     
     
         25 . The process of  claim 22 , further comprising filtering the polyetherimide prior to melting the polymer. 
     
     
         26 . The process of  claim 23 , wherein the polymer is filtered with at least one filter screen wherein each of the at least one filter screen has holes greater than about 10 microns. 
     
     
         27 . The process of  claim 22 , wherein the polymer is melted in an extruder and passed through the hole openings of the spinneret by the extruder. 
     
     
         28 . The process of  claim 22 , wherein the polymer is amorphous. 
     
     
         29 . The process of  claim 22  wherein the cooling medium has a substantially uniform velocity as it is directed toward the fiber bundle emerging from the spinneret. 
     
     
         30 . The process of  claim 22  wherein the cooling medium is a gas. 
     
     
         31 . The process of  claim 30 , wherein the velocity of gaseous cooling media directed toward the fiber bundle ranges from about 0.01 to about 10 meters per second. 
     
     
         32 . The process of  claim 30  wherein the gas is air. 
     
     
         33 . The process of  claim 22 , wherein the melt index of the polymer comprising polyetherimide ranges from about 1.5 to about 2.5. 
     
     
         34 . The process of  claim 22 , wherein the fiber output rate ranges from about 100 meters per minute to about 5000 meters/minute. 
     
     
         35 . The process of  claim 22 , wherein the gaseous cooling medium flowing through the fiber bundle has a temperature that ranges from about 0° C. to about 40° C. 
     
     
         36 . The process of  claim 22 , wherein the gaseous cooling medium flowing through the fiber bundle has a temperature that ranges from about 10° C. to about 24° C. 
     
     
         37 . The process of  claim 22 , wherein the polymer comprises a polyetherimide which is formed from a dianahydride monomer selected from the group consisting of BPADA, ODPA, BPA and BP and a diamine selected from the group consisting of mPD, pPD, DDS and ODA. 
     
     
         38 . The process of  claim 22 , wherein the diameter of the fibers can range from about 0.00001 millimeter to about 2 millimeters 
     
     
         39 . The process of  claim 22 , wherein the fiber has a tenacity of at least about 0.5.g/denier or greater according to ASTM 2256-97. 
     
     
         40 . The process of  claim 22 , wherein the fiber has an elongation at break of at least 10% according to ASTM-02256-97. 
     
     
         41 . The process of  claim 22 , wherein the fiber has an elongation at break of at least 20% according to ASTM-02256-97. 
     
     
         42 . The process of  claim 22 , wherein the fiber has an elongation at break of at least 30% according to ASTM-02256-97. 
     
     
         43 . The process of  claim 22 , wherein the pressure exerted by the polymer on the spinneret is substantially uniform across the inside surface of the spinneret. 
     
     
         44 . The process of  claim 22 , wherein the number of holes in the spinneret ranges from about 20 to about 1000.