Apparatus for extruding cellulose fibers

• US 20090256277A1
• 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 8,029,260 B2
• Time in Patent Office: Days
• US Class Current: 264/177.110
• CPC Class Codes: B29K 2001/00 Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
• CPC Class Codes: D01D 4/025 Melt-blowing or solution-blowing dies
• CPC Class Codes: D01D 5/14 with flowing liquid or gaseous stretching media , e.g. solution-blowing
• CPC Class Codes: D01F 2/00 Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof

Abstract

An apparatus is disclosed for extruding cellulose fibers. The apparatus includes a first member, a second member and a third member all secured together. Multiple nozzles extend outward from the first member and each is designed to direct an aqueous cellulose solution therethrough. As the aqueous solution is extruded, it is accentuated and accelerated by pressurized gas flowing through the first member and the second member and out through first openings formed in the third member. The pressurized gas at least partially surrounds each nozzle and shelters the molten filaments extruded therefrom. The third member also has multiple second openings formed therethrough which are also connected to a source of pressurized gas. The pressurized gas streams exiting each of the second openings function to keep each of the molten filaments from contacting an adjacent molten filament.

Claims

1. An apparatus for extruding cellulose fibers, comprising:

a) a first member having multiple nozzles arranged in rows, each of said nozzles having an inside diameter through which an aqueous solution comprised of cellulose and a solvent can be extruded, and having at least one passage formed therein through which a pressurized gas can be routed;

b) a second member secured to said first member, said second member having multiple corridors formed therethrough which are connected to said at least one passage formed in said first member, and multiple openings formed therein through which said multiple nozzles can pass; and

c) a third member secured to said second member, said third member having multiple first openings formed therethrough, each of said multiple first openings sized to permit one of said multiple nozzles to pass through, each of said multiple first openings being concentrically aligned about each of said multiple nozzles, each of said multiple first openings being connected to said pressurized gas corridors formed in said second member and each capable of emitting pressurized gas therethrough such that said pressurized gas at least partially surrounds said aqueous solution extruded from each of said multiple nozzles, and said third member also having multiple second openings formed therethrough which are connected to said pressurized gas corridors formed in said second member, each of said multiple second openings being positioned adjacent to one of said multiple nozzles in each of said rows, and each of said multiple second openings having a diameter through which said pressurized gas can be emitted.

2. The apparatus of claim 1 capable of forming cellulose fibers having a diameter of less than about 15 microns at a throughput of greater than 0.1 grams/hole/minute.

3. The apparatus of claim 1 capable of forming cellulose fibers having a diameter of less than about 5 microns at a throughput of greater than 0.5 grams/hole/minute.

4. The apparatus of claim 1 wherein said third member has an even number of rows of nozzles with at least one of said nozzles in one row being offset from one of said nozzles in an adjacent row.

5. The apparatus of claim 1 wherein each of said multiple hollow cylindrical tubes has an inside diameter ranging from between about 0.125 millimeters to about 01.25 millimeters.

6. The apparatus of claim 1 wherein each of said multiple nozzles is formed from stainless steel.

7. The apparatus of claim 1 wherein each of said multiple second openings has a venturi formed therein.

8. The apparatus of claim 1 wherein said third member has an odd number of rows, and wherein at least two of said nozzles in one row are offset from two of said nozzles in an adjacent row.

9. The apparatus of claim 1 wherein each of said second openings contains a pin therein.

10. An apparatus for extruding cellulose fibers, comprising:

a) a filter block secured to a dope delivery mechanism, said filter block having a first passageway formed therein through which an aqueous solution comprised of cellulose and a solvent can be routed, and a second passageway formed therein through which a pressurized gas can be routed;

b) a spinnerette secured to said filter block, said spinnerette having multiple nozzles arranged in rows, each of said nozzles having a longitudinal central axis with an inside diameter through which said aqueous solution can be extruded, and said spinnerette having at least one passage formed therethrough which is connected to said second passageway;

c) a gas distribution plate secured to said spinnerette, said gas distribution plate having multiple corridors formed therethrough which are connected to said at least one passage formed in said spinnerette, and multiple openings formed therein through which said multiple nozzles can pass; and

d) an exterior plate secured to said gas distribution plate, said exterior plate having multiple first openings formed therethrough, each of said multiple first openings sized to permit one of said multiple nozzles to pass through, each of said multiple first openings being concentrically aligned about each of said multiple nozzles, each of said multiple first openings being connected to said pressurized gas corridors formed in said gas distribution plate and each capable of emitting pressurized gas therethrough such that said pressurized gas at least partially surrounds said aqueous solution extruded from each of said multiple nozzles, and said exterior plate also having multiple second openings formed therethrough which are connected to said pressurized gas corridors formed in said gas distribution plate, each of said multiple second openings being positioned adjacent to one of said multiple nozzles in each of said rows, at least one of said nozzles being offset from a nozzle in an adjacent row, and each of said multiple second openings having a diameter through which said pressurized gas can be emitted.

11. The apparatus of claim 10 capable of forming cellulose fibers having a diameter of less than about 15 microns at a throughput of greater than 0.1 grams/hole/minute.

12. The apparatus of claim 10 capable of forming cellulose fibers having a diameter of less than about 5 microns at a throughput of greater than 0.5 grams/hole/minute.

13. The apparatus of claim 10 wherein said exterior plate has at least three rows of nozzles with each row containing an equal number of said first and second openings.

14. The apparatus of claim 10 wherein said exterior plate has at least three rows of nozzles with each row containing an unequal number of said first and second openings.

15. The apparatus of claim 10 wherein said exterior plate has at least 20 openings per linear centimeter.

16. An apparatus for extruding cellulose fibers, comprising:

a) a dope delivery mechanism having a first conduit formed therein through which an aqueous solution comprised of cellulose and a solvent can be routed, and a second conduit formed therein through which a pressurized gas can be routed;

b) a filter block secured to said dope delivery mechanism, said filter block having at least two separate passageways formed therethrough, each of said passageways connecting with one of first and second conduits;

c) a spinnerette secured to said filter block, said spinnerette having multiple nozzles arranged in rows, each of said nozzles being an elongated, hollow tube having a longitudinal central axis with a cross-section having an opening through which said aqueous solution can be extruded and having at least one passage formed therein which is connected to said pressurized gas passageway formed in said filter block;

d) a gas distribution plate secured to said spinnerette, said gas distribution plate having multiple corridors formed therein which are connected to said passage formed in said spinnerette for routing said pressurized gas therethrough, and multiple openings formed therethrough each of which is sized to permit one of said multiple nozzles to pass through; and

e) an exterior plate secured to said gas distribution plate, said exterior plate having multiple first openings formed therethrough, each of said multiple first openings sized to permit one of said multiple nozzles to pass through, each of said multiple first openings being concentrically aligned about each of said multiple nozzles, each of said multiple first openings being connected to said pressurized gas corridors formed in said gas distribution plate and each capable of emitting pressurized gas therethrough such that said pressurized gas at least partially surrounds said aqueous solution extruded from each of said multiple nozzles, and said exterior plate also having multiple second openings formed therethrough which are connected to said pressurized gas corridors formed in said gas distribution plate, each of said multiple second openings having a central shaft positioned therein and having a cross-section through which said pressurized gas can be emitted, and at least one of said nozzles in one of each of said rows being staggered from at least one of said nozzles in an adjacent row.

17. The apparatus of claim 16 wherein pressurized gas can pass through said assembly at a velocity of at least 45 meters per second and each of said multiple first openings includes at least two crescent shaped slots.

18. The apparatus of claim 16 wherein said exterior plate has at least 60 openings per linear centimeter.

19. The apparatus of claim 16 wherein said exterior plate has an even number of rows of nozzles with at least three of said nozzles in one row being offset from three of said nozzles in an adjacent row.

20. The apparatus of claim 16 wherein said exterior plate has an odd number of rows of nozzles with at least three of said nozzles in one row being offset from three of said nozzles in an adjacent row.