METHOD AND APPARATUS TO PRODUCE MICRO AND/OR NANOFIBER WEBS FROM POLYMERS, USES THEREOF AND COATING METHOD

• US 20120240369A1
• Filed: 06/15/2010
• Published: 09/27/2012
• Est. Priority Date: 06/15/2009
• Status: Active Grant

• Current Assignee: Empresa Brasileira de Pesquisa Agropecuária
• Original Assignee: Empresa Brasilerira De Pesquisa Agropecuaria - Embrapa
• Inventors: Capparelli Mattoso, Luiz Henrique, Souto De Medeiros, Eliton
• Granted Patent: US 9,650,731 B2
• Time in Patent Office: Days
• US Class Current: 28/104
• CPC Class Codes: D01D 5/003 the material being a polymer solution or dispersion D01D5/0053 takes precedence
• CPC Class Codes: D01D 5/0069 characterised by the spinning section, e.g. capillary tube, protrusion or pin
• CPC Class Codes: D01D 5/0084 Coating by electro-spinning, i.e. the electro-spun fibres are not removed from the collecting device but remain integral with it, e.g. coating of prostheses
• CPC Class Codes: D01F 1/10 Other agents for modifying properties
• CPC Class Codes: D04H 1/728 by electro-spinning electro-spinning methods and apparatus D01D5/0007

Abstract

The present invention refers to an apparatus and method for producing non-woven nanofibers from polymers. The method for producing non-woven micro nanofibers from polymers comprises the use of electrospinning and melt blowing elements. The apparatus presented for producing non-woven micro and/or nanofibers from polymers comprises a source of compressed gas, a pressure gauge, a hypodermic syringe with a pump for controlling the injection rate of the polymeric solutions, a pulverizing apparatus and a collector preferably with controlled rotation speed. The technology presented for producing non-woven micro and/or nanofibers is capable of producing micro and nanofibers having diameters similar to those produced by electrospinning, also on an industrial scale. The invention also comprises the use of non-woven nanofibers in pulverizing live tissues and as coating for materials.

Claims

1. Method for producing micro and/or nanofiber webs from a solution of polymers, characterized by the injection of shear air jets, using a pressure gradient/differential and comprising:

Pumping through at least one inner nozzle the polymeric solution, which comprises at least one polymer dissolved in at least one solvent;

Passing a compressed gas at high speed through an outer nozzle to direct the production of fibers; and

Collecting the polymeric fibers spun in a collector.

2. Method for producing micro and/or nanofiber webs according to claim 1, characterized in that the shear air jets are injected parallely or at an angle in relation to the polymer.

3. Method for producing micro and/or nanofiber webs according to claim 1, characterized in that the polymers are selected from the group of poly (lactic acid), polymethylmethacrylate, polyvinyl alcohol, polystyrene and polyaniline, silk protein, gelatin, collagen, chitosan, polyoxyethylene (PEO), poly(methylmethacrylate) (PMMA), polycaprolactones (PCL), polyamides (PA), polyacrilonitryl (PAN), poly(ethylene terephthalate)(PET), poly(vinyl chloride)(PVC), poly(vinyl pyrrolidone)(PVP), polyurethanes (PU), natural and synthetic rubbers, or compounds derived therefrom.

4. Method for producing micro and/or nanofiber webs according to claim 1, characterized by alternatively allowing the use of more than one polymer in blendes.

5. Method for producing micro and/or nanofiber webs according to claim 4, characterized by alternatively allowing the use of more than one polymer with a “

core/sheath”

structure.

6. Method for producing micro and/or nanofiber webs according to claim 1, characterized in that the concentration of the polymer may vary from about 0.1% to about 70%.

7. Method for producing micro and/or nanofiber webs according to claim 1, characterized in that the solvent may have a dielectric constant varying between low, intermediary and high.

8. Method for producing micro and/or nanofiber webs according to claim 7, characterized in that alternatively the solvent may have a low dielectric constant.

9. Method for producing micro and/or nanofiber webs according to claim 7, characterized in that alternatively the solvent may have an intermediary dielectric constant.

10. Method for producing micro and/or nanofiber webs according to claim 1, characterized in that the solvent is selected from the group of 1,1,1,3,3,3-hexafluoro-2-propanol (HFP), toluene, chloroform, 2,2,2-trifluoroethanol (TFE), acetone, water, acetic acid, formic acid, alcohols, dimethylformamide (DMF), tetrahydrofuran (THF), hexafluoroacetone, hexafluoroisopropyl alcohol, dimethylformamide (DMF), dimethylacetamide (DMAc), methyl ethyl ketone (MEK), dimethyl sulfoxide (DMSO), cyclohexane, among others.

11. Method for producing micro and/or nanofiber webs according to claim 1, characterized in that the polymers in solution may be laden with organic and inorganic particles such as nanofibers made of carbon, cellulose, ZrCO₂, ZnO, CuO, NiO₂, and Mn₃O₄.

12. Method for producing micro and/or nanofiber webs according to claim 1, characterized in that the compressed gas is selected from the group consisting of air, nitrogen, argon and oxygen, carbon dioxide, butane and mixtures thereof.

13. Method for producing micro and/or nanofiber webs according to claim 1, characterized in that the polymeric solution is discharged by compression through the inner nozzle under a discharging pressure in the range of about 1 to 1000 kPa and pumping rate varying in the range of 1 to 1000 μ

L/min.

14. Method for producing micro and/or nanofiber webs according to claim 12, characterized in that preferably the pressure of the pressurized gas (p) may vary in the range of between 60 and 520 kPa and the pumping rate of the polymeric solution varies from about 20 to about 200 μ

l/min.

15. Method for producing micro and/or nanofiber webs according to claim 1, characterized in that the pressurized gas may alternatively be submitted to a heating system.

16. Method for producing micro and/or nanofiber webs according to claim 15, characterized in that the heating system comprises at least an electrical resistance and a passage duct of heated fluid.

17. Method for producing micro and/or nanofiber webs according to claim 15, characterized in that the heating system comprises any system capable of heating the gas used in the melt-blow spinning process.

18. Apparatus for producing micro and/or nanofiber webs from solutions of polymers pursuant to the method in claim 1, characterized by comprising:

a source (1) of compressed gas;

a pressure-regulating device;

a recipient device with controlled stream;

a device for controlling (3) the injection rate of the polymeric solutions;

a pulverizing apparatus (4); and

a collector (5).

19. Apparatus for producing micro and/or nanofiber webs according to claim 18, characterized in that the pulverizing apparatus (4) consists of concentric nozzles.

20. Apparatus for producing micro and/or nanofiber webs according to claim 19, characterized in that the nozzles consist of a system of 3 (three) concentric nozzles, namely:

a first nozzle located more externally through where the gas (air/fluid) is released for spinning;

a second nozzle located more internally through where the polymeric solution forming the center (core) of the fibers is released; and

a third nozzle located at the center, called intermediary, through where the polymer forming the sheath of the fibers exits.

21. Apparatus for producing micro and/or nanofiber webs according to claim 20, characterized in that the second nozzle is provided with a thinner end.

22. Apparatus for producing micro and/or nanofiber webs according to claim 19, characterized in that the collector is selected between rotary or stationary collector.

23. Apparatus for producing micro and/or nanofiber webs according to claim 22, characterized in that the collector selected is rotary.

24. Apparatus for producing micro and/or nanofiber webs according to claim 23, characterized by having a control rotation speed and being positioned preferably at a fixed working distance (6) from the outer nozzle.

25. Apparatus for producing micro and/or nanofiber webs according to claim 23, characterized in that alternatively the collector is located at a mobile working distance during the formation of the fibers.

26. Use of micro and/or nanofiber webs produced according to claim 1, characterized by being used in the pulverization of materials selected from among the group of:

live tissues, in situ, or any other biological and non-biological tissues, or any types of materials of any shape, size and chemical constitution, filtering means, membranes in general, sensors, systems of controlled release of drugs or any other substances, production of micro and nanostructured threads/yarns, cleaning utensils, in impermeable/protective clothing against chemical and biological agents, for cell growth support;

use in wound dressing to protect against infections, burns, anti-radiation, and also use in military applications such as an anti-radar for military camouflage.

27. Method for coating products characterized in that it occurs by means of the use of micro and/or nanofiber web as obtained by claim 1.