RADIATION ABSORPTIVE COMPOSITES AND METHODS FOR PRODUCTION

• US 20070148457A1
• Filed: 09/13/2006
• Published: 06/28/2007
• Est. Priority Date: 09/14/2005
• Status: Abandoned Application

• Current Assignee: NaturalNano, Inc. (Omni Shrimp, Inc.)
• Original Assignee: NaturalNano, Inc. (Omni Shrimp, Inc.)
• Inventors: Wagner, Aaron, Price, Ronald
• Application Number:
  US11/531,459
• Publication Number:
  US 20070148457A1
• Time in Patent Office: Days
• US Class Current: 428/402
• CPC Class Codes: B29C 70/58 comprising fillers only , e.g. particles, powder, beads, flakes, spheres B29C70/025 takes precedence, agglomerating hollow spheres to produce synthetic foam B29C70/66; compounding ingredients per se C08K
• CPC Class Codes: B29C 70/882 partly or totally electrically conductive, e.g. for EMI shielding conductive floors or floor coverings H05F3/025; EMI shielding in general H05K9/00
• CPC Class Codes: C23C 18/1637 metallic substrate
• CPC Class Codes: C23C 18/1644 porous substrates
• CPC Class Codes: C23C 18/1658 with two steps starting with metal deposition followed by addition of reducing agent
• CPC Class Codes: C23C 18/40 using reducing agents
• CPC Class Codes: C23C 18/405 Formaldehyde
• CPC Class Codes: C25D 15/02 Combined electrolytic and electrophoretic processes with charged materials
• CPC Class Codes: G21F 1/085 Heavy metals or alloys
• CPC Class Codes: H01B 1/04 mainly consisting of carbon-silicon compounds, carbon or silicon
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/31609 Particulate metal or metal compound-containing

Abstract

Disclosed are a radiation absorptive material and more particularly a method of economically coating halloysite or other mineral tubules (including nanotubules and microtubules) with a conductive metal (Cu) in order to produce an absorptive composite material capable of providing shielding and attenuation of radio-frequency signals.

Claims

1. A method for the metallization of mineral nanotubes, comprising:

preparing a plating bath consisting essentially of an aqueous solution and a metallic chloride;

exposing a plurality of mineral nanotubes to said bath; and

plating a surface of said nanotubes using a non-precious metal catalyst in association with said bath.

2. The method of claim 1, wherein preparing a plating bath includes preparing a bath using deionized water EDTA solution, and a copper chloride in an aqueous solution.

3. The method of claim 1, wherein exposing a plurality of mineral nanotubes to said bath includes:

preparing a mineral nanotube slurry including sodium hydroxide in an aqueous solution, mineral nanotubes, and deionized water;

sonicating the slurry to mix and distribute the mineral nanotubes; and

introducing the mineral nanotube slurry to the bath to create a mixture.

4. The method of claim 3, wherein said mineral nanotubes include halloysite nanotubes.

5. The method of claim 3, further comprising:

adding formaldehyde to the mixture; and

increasing the pH of the mixture to catalyze the metallization process.

6. The method of claim 5, further comprising:

applying heat and vacuum to the mixture, and subsequently returning the mixture to ambient pressure;

adding a water-soluble reducing agent; and

stirring the mixture.

7. The method of claim 1, further comprising separating metallized solids from liquid in the bath.

8. The method of claim 7, wherein the process for separating the solids from liquid is selected from the group consisting of:

filtering;

decanting; and

centrifuging.

9. The method of claim 6, further comprising:

centrifuging the mixture;

removing liquid from the centrifuged mixture and re-hydrating the mixture with deionized water;

repeating the steps above as necessary until the solids have been thoroughly rinsed;

removing the solids using isopropyl alcohol; and

drying the solids.

10. A method of electromagnetic shielding, comprising:

providing a composition including tubular, metal-coated particles and a polymer dispersion, where said metal-coated particles are produced using an electroless non-precious metal catalyst process;

applying the composition to a surface to be shielded; and

curing the applied composition.

11. The method of claim 10, wherein said tubular, metal-coated particles are halloysite nanotubes coated with electroless copper over at least one surface thereof.

12. The method of claim 11, further including coating said halloysite nanotubes with electroless copper using a process comprising:

preparing a plating bath consisting essentially of an aqueous EDTA solution and copper chloride;

exposing a plurality of halloysite nanotubes to said bath by preparing a halloysite nanotube slurry including sodium hydroxide, halloysite nanotubes, and deionized water;

sonicating the slurry to mix and distribute the nanotubes; and

introducing the slurry to the bath to create a mixture; and

plating a surface of said nanotubes using a non-precious metal catalyst in association with said bath

13. The method of claim 12, further comprising adding formaldehyde to the mixture to catalyze the metallization process.

14. The method of claim 13, further comprising:

applying heat and vacuum to the mixture, and subsequently returning the mixture to ambient pressure;

adding a water-soluble reducing agent; and

stirring the mixture.

15. The method of claim 10, wherein said polymer dispersion includes a polyvinyl material with acrylic resin.

16. The method of claim 10, wherein applying the composition to a surface includes a method selected from the group consisting of:

spreading;

flow-coating;

spraying; and

electrodeposition.

17. A composite material, comprising:

a polymeric matrix; and

a plurality of metallized mineral tubules dispersed within at least a portion of said polymeric matrix, wherein said metallized mineral tubules are coated using an electroless, non-precious metal plating process.

18. The material of claim 17, wherein said tubules include halloysite nanotubules.

19. The method of claim 18, wherein said halloysite nanotubules include metallic copper on a surface thereof.

20. The material of claim 17, wherein said polymeric matrix includes an acrylic urethane latex paint.

21. The material of claim 20, wherein said acrylic urethane latex paint is applied to the surface of an object.

22. The material of claim 17, wherein the material is formed into a component using a process selected from the group consisting of:

molding, compounding, extrusion, co-extrusion, rotomolding, thermoforming, vacuum forming, calendaring, matched-die molding, hand lay-up, filament winding, casting, and forging.