Magnetic sheet, method of making the same, and loud speaker including the same

Patent metadata

Field	Value
Publication number	US-10217551-B2
Application number	US-201615190923-A
Country	US
Kind code	B2
Filing date	Jun 23, 2016
Priority date	Dec 22, 2015
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

A magnetic sheet having a magnetic material particle comprising a hexaferrite and a nanofiber matrix made of two or more nanofibers, wherein the magnetic material particle is dispersed in the nanofiber matrix. A manufacturing method thereof and a speaker including the magnetic sheet are also provided.

First claim

What is claimed is:

1. A magnetic sheet comprising:
a magnetic material particle comprising a hexaferrite;
a nanofiber matrix comprising two or more nanofibers; and
a coupling material chemically coupled with each of the magnetic material particle and the nanofiber matrix,
wherein the magnetic material particle satisfies Chemical Formula 1 or Chemical Formula 2:
A 1-x R x Fe 12-y M y O 19   Chemical Formula 1

AQ 2 Fe 16 O 27   Chemical Formula 2

wherein, in Chemical Formula 1, A is one or more elements selected from Sr, Ba, and Ca, R is one or more elements selected from rare earth elements, M is one or more elements selected from Co, Mn, Zn, Zr, Ni, Ti, Cu, Al, Ge, and As, 0≤x≤0.6, and 0≤y≤1.2,
wherein, in Chemical Formula 2, A is one or more elements selected from Sr, Ba, and Ca, and Q is one or more elements selected from Cu, Zn, Mn, and Ni,
wherein the nanofiber matrix coupled to the magnetic material particle is pressed at a pressure of 20 MPa to 80 MPa, such that the tensile strength of the magnetic sheet is about equal to the tensile strength of a substantially identical sheet without the magnetic material and coupling material.

2. The magnetic sheet of claim 1 , wherein
the magnetic material particle comprises at least one of an M-type hexaferrite and a W-type hexaferrite.

3. The magnetic sheet of claim 1 , wherein
the magnetic material particle is a hard magnetic material.

4. The magnetic sheet of claim 1 , wherein
the magnetic material particle is present in an amount of 5 wt % or more with reference to an entire weight of the magnetic sheet.

5. The magnetic sheet of claim 1 , wherein
a size of the magnetic material particle is more than 0 μm to less than 50 μm.

6. The magnetic sheet of claim 1 , wherein
a diameter of each nanofiber of the two or more nanofibers is in a range of 5 nm to 100 nm.

7. The magnetic sheet of claim 1 , wherein
each nanofiber of the two or more nanofibers comprises a cellulose nanofiber.

8. The magnetic sheet of claim 1 , wherein
the coupling material is a silane compound comprising a hydrophilic group.

9. The magnetic sheet of claim 8 , wherein
the silane compound comprises repeating units derived from a monomer represented by Chemical Formula 3:

10. The magnetic sheet of claim 1 , wherein
the coupling material comprises at least an amine functional group.

11. The magnetic sheet of claim 1 , wherein the magnetic material particle and the coupling material are bonded by a covalent bond or a hydrogen bond.

12. The magnetic sheet of claim 11 , wherein the covalent bond includes an ether bond (—O—).

13. A speaker comprising:
a reel-type structure which is rolled with a coil;
the magnetic sheet of claim 1 , the magnetic sheet disposed on the reel-type structure;
a first frame disposed on the magnetic sheet; and
a second frame disposed on the first frame.

14. A method for manufacturing the magnetic sheet of claim 1 , comprising:
synthesizing the magnetic material particle;
mixing the magnetic material particle with a solution comprising a nanofiber to form a nanofiber matrix; and
drying the formed nanofiber matrix and the magnetic material particle.

15. The method of claim 14 , wherein
synthesizing the magnetic material particle comprises solvothermal synthesis.

16. The method of claim 15 , wherein
the solvothermal synthesis is performed at a temperature of 200° C. to 400° C.

17. The method of claim 14 , further comprising
processing coupling of the synthesized magnetic material particle.

18. The method of claim 14 , wherein
the nanofiber matrix and the magnetic material particle are pressed during drying.

Assignees

• Samsung Electronics Co Ltd
• Research & Business Found Sungkyunkwan Univ

Inventors

• Lee Sang-Eui
• Lim Byungkwon
• Moon Kyoung-Seok
• Han In Taek
• Kang Jin Kyu
• Ahn Jin Ho
• Kwon Nayoung
• Bok Shingyu
• Sim Hwansu
• Lee Jooyoung
• Lim Guh-Hwan

Classifications

• Y10T428/25

  Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles · CPC title

• H01F41/0253

  for manufacturing permanent magnets · CPC title

• B32B5/02

  characterised by structural features of a {fibrous or filamentary} layer {(layer formed of metallic wires B32B15/02; layer formed of natural mineral fibres B32B19/02; layer formed of wood fibres B32B21/02)} · CPC title

• Y10T428/32

  Composite [nonstructural laminate] of inorganic material having metal-compound-containing layer and having defined magnetic layer · CPC title

• Y10T428/2982

  Particulate matter [e.g., sphere, flake, etc.] · CPC title