Polyetherimide polymer for use as a high heat fiber material
View Patent ↗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 process for making polymer fiber, the process comprising:
melting a polymer consisting of polyetherimide to a melt temperature that ranges from about 180° C. to about 500° C., to produce a molten polyetherimide;
passing the molten polyetherimide through a filter with at least one filter screen wherein each of the at least one filter screen has holes greater than about 25 microns;
passing the filtered molten polyetherimide through a spinneret comprising a plurality of hole openings to produce a fiber bundle, wherein the filtered molten polymer is substantially free of foreign particulate matter having a size greater than about 25 μm in size and greater than or equal to 50% of the diameter of the fiber; and
cooling the fiber bundle with a gaseous cooling medium, the cooling medium having a temperature that ranges from about 0° C. to about 80° C. and a substantially uniform velocity distribution, to produce fiber.
2. The process of claim 1 , further comprising filtering the polyetherimide prior to melting the polymer.
3. The process of claim 1 , wherein the polymer is melted in an extruder and passed through the hole openings of the spinneret by the extruder.
4. The process of claim 1 , wherein the polymer is amorphous.
5. The process of claim 1 wherein the cooling medium has a substantially uniform velocity as it is directed toward the fiber bundle emerging from the spinneret.
6. The process of claim 1 , wherein the velocity of gaseous cooling media directed toward the fiber bundle ranges from about 0.01 to about 10 meters per second.
7. The process of claim 1 wherein the gas is air.
8. The process of claim 1 , wherein the melt index of the polyetherimide ranges from about 1.5 to about 2.5.
9. The process of claim 1 , wherein the fiber output rate ranges from about 100 meters per minute to about 5000 meters/minute.
10. The process of claim 1 , wherein the gaseous cooling medium flowing through the fiber bundle has a temperature that ranges from about 0° C. to about 40° C.
11. The process of claim 1 , wherein the gaseous cooling medium flowing through the fiber bundle has a temperature that ranges from about 10° C. to about 24° C.
12. The process of claim 1 , wherein the polymer is a polyetherimide which is formed from a dianhydride 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.
13. The process of claim 1 , wherein the diameter of the fibers can range from about 0.00001 millimeter to about 2 millimeters.
14. The process of claim 1 , wherein the fiber has a tenacity of at least about 0.5.g/denier or greater according to ASTM 2256-97.
15. The process of claim 1 , wherein the fiber has an elongation at break of at least 10% according to ASTM-02256-97.
16. The process of claim 1 , wherein the fiber has an elongation at break of at least 20% according to ASTM-02256-97.
17. The process of claim 1 , wherein the fiber has an elongation at break of at least 30% according to ASTM-02256-97.
18. The process of claim 1 , wherein the pressure exerted by the polymer on the spinneret is substantially uniform across the inside surface of the spinneret.
19. The process of claim 1 , wherein the number of holes in the spinneret ranges from about 20 to about 1000.