Claims
- 1. A process for melt spinning a composition comprising a highly fluorinated thermoplastic polymer, comprising the steps of:
melting a composition comprising a highly fluorinated thermoplastic polymer to form a molten fluoropolymer composition; conveying said molten fluoropolymer composition under pressure to an extrusion die of an apparatus for melt spinning; and extruding the molten fluoropolymer composition through the extrusion die to form filaments, said die being at a temperature of at least 450° C., at a shear rate of at least 100 sec−1, at a spinning speed of at least 500 m/min.
- 2. The process of claim 1 further comprising shielding the filaments.
- 3. The process of claim 1 further comprising exposing the molten fluoropolymer composition to an intermediate temperature ranging between the melting temperature of said composition and a temperature less than the temperature of the extrusion die prior to extruding said composition through the extrusion die.
- 4. The process of claim 1 wherein the highly fluorinated polymer has a melt flow rate of 1 to 50 g/10 minutes at 372° C.
- 5. The process of claim 1 wherein the fluorinated polymer is a copolymer of tetrafluoroethylene and a perfluoroolefin.
- 6. The process of claim 5 wherein the fluorinated polymer is a copolymer of tetrafluoroethylene and hexafluoropropylene.
- 7. The process of claim 5 wherein the fluorinated polymer is a copolymer of tetrafluoroethylene and a perfluoroalkylvinyl ether.
- 8. The process of claim 7 wherein the perfluoroalkyl vinyl ether is perfluoromethylvinyl ether, perfluoroethylvinyl ether, or perfluoropropylvinyl ether.
- 9. The process of claim 1 wherein the temperature of the die is at least 500° C.
- 10. The process of claim 1 wherein the extrusion die is thermally isolated from other areas of the apparatus that may contain the fluoropolymer composition.
- 11. The process of claim 1 wherein the spinning speed is at least 1000 m/min.
- 12. The process of claim 1 wherein the shear rate is at least 500 sec−1.
- 13. The process of claim 1 further comprising drawing the fibers.
- 14. The process of claim 1 further comprising a relaxation stage.
- 15. A process for melt spinning a composition comprising polytetrafluoroethylene homopolymer, comprising the steps of: melting a composition comprising polytetrafluoroethylene homopolymer to form a molten polytetrafluoroethylene composition; conveying said molten polytetrafluoroethylene composition under pressure to an extrusion die of an apparatus for melt spinning; and extruding the molten polytetrafluoroethylene composition through the extrusion die to form molten filaments.
- 16. The process of claim 15 wherein the temperature of the extrusion die is at least 450° C.
- 17. The process of claim 15 wherein the spinning speed is at least 50 mpm.
- 18. The process of claim 17 wherein the spinning speed is at least 200 mpm.
- 19. The process of claim 18 wherein the spinning speed is at least 500 mpm.
- 20. The process of claim 15 further comprising shielding the filaments.
- 21. An apparatus for melt-spinning fibers, comprising:
a spinneret assembly comprising:
means for filtering; a spinneret; an elongated transfer line, said transfer line being disposed between said filtration means and said spinneret; means for heating said elongated transfer line; means for heating said spinneret; and an elongated annealer disposed beneath said spinneret assembly.
- 22. The apparatus of claim 21 wherein the elongated annealer comprises an inner tube disposed within an outer tube, said inner tube and said outer tube separated from each other by an annular space.
- 23. The apparatus of claim 22 further comprising a mesh tube disposed adjacent the inner wall of said inner tube extending at least partially down the length of said inner tube.
- 24. The apparatus of claim 22 further comprising at least one perforated plate disposed within said annular space, extending radially with respect to the circumference of said outer tube, and attached to the outer wall of said inner tube or the inner wall of said outer tube, or to both tubes.
- 25. The apparatus of claim 24 further comprising a screen placed on or in close proximity to the at least one perforated plate.
- 26. The apparatus of claim 21 wherein the elongated annealer further comprises means for measuring or controlling air flow rate.
- 27. The apparatus of claim 21 wherein the spinneret is removable.
- 28. The apparatus of claim 21 wherein the transfer line is removable.
- 29. The apparatus of claim 21 wherein said means for heating the spinneret is a conduction heater, a convection heater or an induction heater.
- 30. The apparatus of claim 21 wherein the spinneret has a plurality of extrusion holes all of which are arranged in one circle.
- 31. The apparatus of claim 21 further comprising means for accumulating the spun filaments.
- 32. Oriented monofilament or multifilament yarn of highly fluorinated thermoplastic polymer wherein the orientation of the filaments are greater in the core of the filaments than at the surface of the filaments.
- 33. The yarn of claim 32 having a tenacity of at least 2 g/d .
- 34. The yarn of claim 33 having an elongation of at least 15%.
- 35. The yarn of claim 32 wherein said polymer is ethylene/tetrafluoroethylene copolymer
- 36. Sewing thread containing the yarn of claim 32.
- 37. Dental floss containing the yarn of claim 32.
- 38. Fishing line containing the yarn of claim 32.
- 39. Staple fiber of the yarn of claim 32.
- 40. The yarn of claim 32 containing colorant
- 41. Process for making monofilament or multifilament yarn of highly fluorinated thermoplastic polymer comprising melt spinning said polymer at a temperature above the melting point of said polymer which is effective to produce said yarn wherein the filaments thereof are oriented greater in the core of said filaments than at the surface thereof.
- 42. The process of claim 41 wherein said melt spinning is carried out at a temperature of at least 90° C. greater than the melting point of said polymer.
- 43. The process of claim 42 wherein said yarn is produced at a speed of at least 500 m/min.
- 44. Oriented monofilament or multifilament yarn of ethylene/tetrafluoroethylene copolymer having a tenacity of at least 2 g/d and elongation of at least 15%.
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. Ser. No. 09/857,573, filed Jun. 5, 2001, which is the national filing from PCT application US00/0218, filed Jan. 28, 2000, which claims the benefit of U.S. applications No. 60/117,831, filed Jan. 29, 1999, and No. 60/109,631, filed Dec. 8, 1999, both now abandoned, and claims the benefit of all these applications.
Provisional Applications (2)
|
Number |
Date |
Country |
|
60117831 |
Jan 1999 |
US |
|
60109631 |
Nov 1998 |
US |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
09857573 |
Jun 2001 |
US |
Child |
09920701 |
Aug 2001 |
US |