Array of nozzles for extruding multiple cellulose fibers

• US 20090258099A1
• Filed: 04/11/2008
• Published: 10/15/2009
• Est. Priority Date: 04/11/2008
• Status: Active Grant

• Current Assignee: Reifenhauser GmbH & Co
• Original Assignee: Biax Fiberfilm
• Inventors: Stark, Jeffrey D., Zacharias, Duane K., Brown, Douglas B., Granato, Carmen A. SR.
• Granted Patent: US 8,029,259 B2
• Time in Patent Office: Days
• US Class Current: 425/72.200
• CPC Class Codes: B29C 2791/007 Using fluid under pressure
• CPC Class Codes: B29C 48/001 Combinations of extrusion moulding with other shaping operations
• CPC Class Codes: B29C 48/05 Filamentary, e.g. strands
• CPC Class Codes: B29C 48/1472 at the die nozzle exit zone
• CPC Class Codes: B29C 48/32 with annular openings, e.g. for forming tubular articles
• CPC Class Codes: B29C 48/345 Extrusion nozzles comprising two or more adjacently arranged ports, for simultaneously extruding multiple strands, e.g. for pelletising
• CPC Class Codes: B29C 48/355 Conveyors for extruded articles
• CPC Class Codes: B29K 2001/00 Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
• CPC Class Codes: B29L 2031/731 Filamentary material, i.e. comprised of a single element, e.g. filaments, strands, threads, fibres cables B29L2031/707

Abstract

An array of nozzles is disclosed for forming multiple cellulose fibers. Each nozzle has a longitudinal central axis and includes a tube with a cross-section having a diameter through which an aqueous solution of cellulose and a solvent can be extruded into a molten filament. A first opening is present which surrounds each of the tubes. The first opening has a cross-section with a diameter, and each of the first openings is capable of emitting a pressurized gas which surrounds one of the extruded molten filaments. At least three second openings are spaced away from each of the first openings. Each of the second openings is capable of emitting a pressurized gas stream essentially parallel to the longitudinal central axis of each of the nozzles, and each of the pressurized gas streams functions to shroud one of the extruded molten filaments.

Claims

1. An array of nozzles for extruding multiple cellulose fibers, comprising:

a) multiple nozzles each having a longitudinal central axis and each including a tube with a cross-section having a diameter through which an aqueous solution comprised of cellulose and a solvent can be extruded into a molten filament, and a first opening surrounding each of said tubes having a cross-section with a diameter, said diameter of said first opening being greater than said diameter of said tube, and each of said first openings capable of emitting a pressurized gas which surrounds one of said extruded molten filaments; and

b) at least three second openings each spaced outward from each of said first openings, each of said second openings capable of emitting a pressurized gas stream essentially parallel to said longitudinal central axis of said nozzle, and each of said pressurized gas streams functioning to shroud one of said extruded molten filaments.

2. The array of claim 1 wherein said pressurized gas emitted from each of said first openings attenuates and accelerates each of said molten filaments extruded from each of said tubes into a continuous fiber having a diameter of less than about 15 microns.

3. The array of claim 1 wherein each of said first and second openings is aligned parallel to one another.

4. The array of claim 1 wherein each of said second openings is spaced from between about 1 millimeter to about 4 millimeters from said longitudinal central axis of said nozzle.

5. The array of claim 4 wherein each of said second openings is spaced from between about 1 millimeter to about 2 millimeters from said longitudinal central axis of one of said nozzles.

6. The array of claim 1 wherein each of said tubes extends downward beyond said first openings by at least 1 millimeter.

7. The array of claim 6 wherein each of said tubes extends downward beyond said first openings by at least 3 millimeters.

8. The array of claim 7 wherein each of said tubes extends downward beyond said first openings by at least 5 millimeters.

9. The array of claim 1 wherein said second opening has a venturi.

10. An array of nozzles for extruding multiple cellulose fibers, comprising:

a) multiple nozzles each having a longitudinal central axis and each including a hollow cylindrical tube with a cross-section having a constant diameter through which an aqueous solution comprised of cellulose and a water soluble solvent can be extruded into a molten filament, and a first opening surrounding each of said hollow cylindrical tubes and having a cross-section with a constant diameter, said diameter of each of said first openings being greater than said diameter of each of said hollow cylindrical tubes, and each of said first openings capable of emitting a pressurized gas which at least partially surrounds one of said extruded molten filaments; and

b) a plurality of second openings each spaced outward from each of said first openings, each of said second openings capable of emitting a pressurized gas stream essentially parallel to said longitudinal central axis of each of said nozzles, and each of said pressurized gas streams functioning to shroud one of said extruded molten filaments.

11. The array of claim 10 wherein there are at least three second openings for each first opening and each of said second openings is equally spaced apart from an adjacent second opening.

12. The array of claim 10 wherein there are eight second openings for each first opening and each of said second openings is spaced approximately 45 degrees apart.

13. The array of claim 10 wherein each of said hollow cylindrical tubes extends downward beyond said first opening by a distance of at least about 5 millimeters.

14. The array of nozzles of claim 10 wherein each of said hollow cylindrical tubes has an internal diameter ranging from between about 0.125 millimeters to about 1.25 millimeters.

15. The array of nozzles of claim 14 wherein each of said hollow cylindrical tubes is formed from stainless steel.

16. An array of nozzles for extruding multiple cellulose fibers, comprising:

a) multiple nozzles arranged in rows, each of said nozzle having a longitudinal central axis and including a hollow cylindrical tube with a cross-section and having a constant diameter positioned therein through which an aqueous solution comprised of cellulose and a water soluble solvent can be extruded into a molten filament, and a first opening concentrically aligned about each of said hollow cylindrical tubes and having a cross-section with a constant diameter, said diameter of said first opening being greater than said diameter of each of said hollow cylindrical tubes, and said first opening capable of emitting pressurized gas therethrough which at least partially surrounds said extruded molten filament;

b) multiple second openings arranged in said rows with said multiple nozzles, at least two of said second openings being positioned adjacent to one of said nozzles in each of said rows, each of said second openings having a pin positioned therein and having a diameter through which a pressurized gas can be emitted; and

c) at least one of said nozzles in one row being offset from one of said nozzles in an adjacent row.

17. The array of claim 16 wherein each of said first openings includes at least two crescent shaped slots spaced apart from said hollow cylindrical tube.

18. The array of claim 16 wherein each of said hollow cylindrical tubes is vertically spaced downward from each of said first openings by at least 3 millimeters.

19. The array of claim 16 wherein said second opening has a venturi formed therein.

20. The array of claim 16 wherein each of said second openings has a sidewall aligned perpendicular to each of said second openings.