LOUDSPEAKER CONE BODY

• US 20090074228A1
• Filed: 09/12/2008
• Published: 03/19/2009
• Est. Priority Date: 09/13/2007
• Status: Active Grant

• Current Assignee: Harman International Industries Incorporated (Samsung Electronics Co. Ltd.)
• Original Assignee: Harman International Industries Incorporated (Samsung Electronics Co. Ltd.)
• Inventors: Pilatowski, Ryszard A., Steere, John F., Mango, Louis A. III, Stewart, John S.
• Granted Patent: US 9,247,368 B2
• Time in Patent Office: Days
• US Class Current: 381/432
• CPC Class Codes: H04R 31/003 for diaphragms or their outer suspension
• CPC Class Codes: Y10T 29/49005 Acoustic transducer

Abstract

A loudspeaker cone body made of paper may include a chemically-bound nanomaterial, such as a carbon nanotube. The carbon nanotube may be chemically bound to a functionalizing agent having a chemical group chemically bound to one or more papermaking additives, such as a sizing agent or a wet strength agent, a dry strength agent, a resin or cellulose-containing papermaking stock material typically present in a paper loudspeaker cone body, such as pulp. Acoustic-related loudspeaker performance characteristics such as stiffness to weight ratio and an acoustic damping of the loudspeaker cone body may be altered by incorporation of the nanomaterials chemically bound to the loudspeaker cone body.

Claims

1. A method of forming a loudspeaker cone comprising:

(a) contacting in a liquid medium a modified carbon nanotube that includes a first binding moiety with at least one of a paper-forming compound and a paper-treatment compound in a manner effective to retain the modified carbon nanotube to the one of the paper-forming compound and the paper-treatment compound to form a first adduct, the paper-forming and the paper-treatment compound together forming a paper compound; and

(b) forming the loudspeaker cone by one or more of the following;

(i) removing the liquid medium from the paper compound and the first adduct; and

(ii) reacting the first adduct with the paper compound n a manner effective to chemically bind the modified carbon nanotube to the paper compound.

2. The method of claim 1, where the paper-forming compound is a papermaking cellulose stock and the paper-treatment compound includes functional additives and control additives, the control additives including a retention aide and at least one of a formation aide, a drainage agent, a foam control, a biocide, a corrosion control additive and a buffer, and the step of contacting in the liquid medium includes contacting the modified carbon nanotube with at least one of the papermaking cellulose stock and the retention aide to form the first adduct and adding the functional and control additives to the liquid medium to form a final furnish defining the paper compound in the liquid medium.

3. The method of claim 2, where the step of forming the loud speaker includes forming a filter mass containing the paper compound, the first adduct and residual liquid medium, and the step of reacting the first adduct includes heating the filter mass in a manner effective to substantially remove the residual liquid medium and cure the first adduct with at least one of the control additives, functional additives and the paper-forming compound.

4. The method of claim 1, where the paper-forming compound includes cellulose fibers and the first adduct includes the modified carbon nanotube coupled to cellulose fibers via one of electrostatic charge and/or dipole attraction.

5. The method of claim 1, where the liquid medium is water and the modified carbon nanotube develops an anionic or cationic surface character in the water to form the first adduct.

6. The method of claim 1, where the step of reacting the first adduct occurs after the step of removing the liquid medium.

7. The method of claim 1, where the step of removing the liquid medium includes heating the liquid medium and the paper compound with process heat, and the step of reacting the first adduct includes chemically bonding the first adduct to the paper compound with the process heat.

8. The method of claim 1, where the modified carbon nanotube is chemically bound to the paper compound by one of covalent, ionic and hydrogen bonding.

9. The method of claim 1, where the first binding moiety is selected from the group consisting of epoxy, amine, ammonium, hydroxyl, carboxylate and carboxylic acid.

10. The method of claim 1, where the paper-forming compound includes a cellulose-containing compound and the modified carbon nanotube is retained with the cellulose-containing compound to form the first adduct.

11. The method of claim 1, where the paper-treatment compound includes additives selected from the group consisting of an internal sizing agent, a surface sizing agent, a wet strength additive, a dry strength additive, a retention aide and drainage agent.

12. The method of claim 1, where the step of removing the liquid medium includes filtering the paper compound and the first adduct to form a filtrate, and pressing the filtrate to form a green stock composition, and where the step of reacting the first adduct includes hot pressing the green stock composition to form the loudspeaker cone.

13. A method of forming a loudspeaker cone comprising:

contacting paper-forming compound including cellulose with a liquid medium and agitating to produce a thick stock;

contacting in the liquid medium a modified carbon nanotube that includes a first binding moiety with the thick stock and a paper-treatment compound that includes a retention aide in a manner effective to retain the modified carbon nanotube with the cellulose to form a first adduct;

adding additional paper-treatment compound including functional and control additives to form a final papermaking furnish, the paper-forming compound and the paper-treatment together forming a paper compound;

diluting the final papermaking furnish with additional liquid medium to form a thin stock;

depositing the thin stock onto a filtering medium;

progressively removing the liquid medium from the thin stock to produce a wet paper compound; and

forming the loudspeaker cone including;

applying heat to the wet paper compound to remove residual liquid medium from the paper compound and the first adduct; and

reacting the first binding moiety and the paper compound in a manner effective to chemically bound the modified carbon nanotube to the paper compound.

14. The method of claim 13, where the first adduct includes the modified carbon nanotube coupled to the cellulose via one of electrostatic charge and dipole attraction.

15. The method of claim 13, where the liquid medium is water and the modified carbon nanotube develops one of an anionic and cationic surface character when in water to form the first adduct.

16. The method of claim 13, where the step of reacting the first binding moiety occurs after the step of removing the liquid medium.

17. The method of claim 13, where the step of removing the liquid medium includes heating the liquid medium and the paper compound with process heat, and the step of reacting the first binding moiety includes chemically bonding the first adduct to the paper compound with the process heat.

18. The method of claim 13, where the modified carbon nanotube is chemically bound to the paper compound by one of covalent, ionic and hydrogen bonding.

19. The method of claim 13, where the step of adding paper-treatment compound is subsequent to the step of contacting the paper-forming compound.

20. A loudspeaker comprising:

a paper loudspeaker cone including;

a modified carbon nanotube chemically bound to at least one of a cellulose-containing compound and a papermaking additive, the papermaking additive including material selected from the group consisting of a sizing agent, a resin, a wet strength additive, a dry strength additive and a retention and drainage agent.