Apparatus for improving mechanical characteristics of nonwoven materials

• US 7,244,116 B2
• Filed: 03/19/2002
• Issued: 07/17/2007
• Est. Priority Date: 12/19/2000
• Status: Expired due to Fees

• Current Assignee: Nicast Ltd.
• Original Assignee: Nicast Ltd.
• Inventors: Bar, Eli, Dubson, Alexander
• Primary Examiner(s): Gupta; Yogendra N.
• Assistant Examiner(s): Ewald; Maria Veronica
• Application Number:
  US10/471,277
• Publication Number:
  US 20040096533A1
• Time in Patent Office: 1,946 Days
• Field of Search: 425/174.8 E, 425/174.8 R
• US Class Current: 425/174.80R
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2002/072 Encapsulated stents, e.g. wire or whole stent embedded in lining
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• CPC Class Codes: A61F 2250/0023 differing in porosity
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61L 27/507 for artificial blood vessels apparatus for applying cells on a blood vessel prosthesis A61F2/062
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: B29C 67/20 for porous or cellular articles, e.g. of foam plastics, coarse-pored chemical aspects of working up macro-molecular substances to porous or cellular articles C08J9/00
• CPC Class Codes: D01D 5/0007 Electro-spinning non-woven fabrics produced by electro-spinning D04H1/728
• CPC Class Codes: D01D 5/0069 characterised by the spinning section, e.g. capillary tube, protrusion or pin
• CPC Class Codes: D01D 5/0092 characterised by the electrical field, e.g. combined with a magnetic fields, using biased or alternating fields
• CPC Class Codes: D01D 5/18 by means of rotating spinnerets
• CPC Class Codes: D04H 1/728 by electro-spinning electro-spinning methods and apparatus D01D5/0007
• CPC Class Codes: D04H 3/07 otherwise than in a plane, e.g. in a tubular way
• CPC Class Codes: D04H 3/16 with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion
• CPC Class Codes: Y10T 428/13 Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/1372 Randomly noninterengaged or randomly contacting fibers, filaments, particles, or flakes
• CPC Class Codes: Y10T 428/139 : Open-ended, self-supporting conduit, cylinder, or tube-type article
• CPC Class Codes: Y10T 428/1393 : Multilayer [continuous layer]
• CPC Class Codes: Y10T 442/614 : Strand or fiber material specified as having microdimensions [i.e., microfiber]

Abstract

An apparatus for forming a nonwoven material from a liquefied polymer, the apparatus comprising: (a) a precipitation electrode; (b) a dispenser spaced apart from the precipitation electrode, and defining a first axis therebetween, the dispenser being at a first potential relative to the precipitation electrode; and (c) a system of electrodes being laterally displaced from the dispenser, being at a second potential relative to the precipitation electrode and capable of providing an electric field having at least one rotating component about the first axis; the dispenser and the system of electrodes being designed and constructed such that the liquefied polymer is dispensed from the dispenser and forms a plurality of entangled fibers moving in a direction of the precipitation electrode, hence forming the nonwoven material thereupon.

Claims

1. An apparatus for forming a nonwoven material from a liquefied polymer, the apparatus comprising:

(a) a precipitation electrode;

(b) a dispenser spaced apart from said precipitation electrode, and defining a first axis therebetween, said dispenser being at a first potential relative to said precipitation electrode; and

(c) at least one rotating electrode being laterally displaced from said dispenser, being at a second potential relative to said precipitation electrode and operable to rotate around said first axis;

said dispenser and said at least one rotating electrode being designed and constructed such that the liquefied polymer is dispensed from said dispenser and forms a plurality of entangled fibers moving in a direction of said precipitation electrode, hence forming the nonwoven material thereupon.

2. The apparatus of claim 1, wherein said precipitation electrode is operable to rotate around a second axis.

3. The apparatus of claim 2, wherein said first axis and said second axis are substantially orthogonal.

4. The apparatus of claim 2, wherein said first axis and said second axis are substantially parallel.

5. The apparatus of claim 1, wherein said precipitation electrode is selected from the group consisting of a cylindrical precipitation electrode and a flat precipitation electrode.

6. The apparatus of claim 1, herein said dispenser and said at least one rotating electrode are operable to synchronously move along said precipitation electrode.

7. The apparatus of claim 1, wherein said dispenser and said at least one rotating electrode are operative to independently move along said precipitation electrode.

8. The apparatus of claim 1, wherein said dispenser comprises a mechanism for forming a jet of the liquefied polymer.

9. The apparatus according to claim 8, wherein said mechanism for forming a jet of the liquefied polymer includes a dispensing electrode.

10. The apparatus according to claim 1, further comprising a bath for holding the liquefied polymer.

11. The apparatus of claim 2, further comprising a subsidiary electrode being positioned close to said precipitation electrode and being at a third potential relative to said precipitation electrode, said subsidiary electrode being for modifying an electric field generated by said precipitation electrode, said dispenser and said at least one rotating electrode.

12. The apparatus of claim 11, wherein said subsidiary electrode is designed and constructed such as to reduce non-uniformities in said electric field.

13. The apparatus of claim 11, wherein said subsidiary electrode is designed and constructed such as to control fiber orientation of the nonwoven material formed upon said precipitation electrode.

14. The apparatus of claim 11, wherein said subsidiary electrode is of a shape selected from the group consisting of a plane, a cylinder, a torus and a wire.

15. The apparatus of claim 11, wherein said subsidiary electrode is operative to move along said second axis.

16. The apparatus according to claim 11, wherein said subsidiary electrode is tilted at an angle with respect to said second axis.