Magnetic sheet

Patent metadata

Field	Value
Publication number	US-12567535-B2
Application number	US-202217682380-A
Country	US
Kind code	B2
Filing date	Feb 28, 2022
Priority date	Mar 4, 2021
Publication date	Mar 3, 2026
Grant date	Mar 3, 2026

Abstract

A magnetic sheet is used as a noise reduction member for a cable. The magnetic sheet has a width of 5 mm to 15 mm. The magnetic sheet has a magnetic layer and a protective layer. The magnetic layer comprises soft-magnetic particles and a binder. Each of the soft-magnetic particles has a flat shape. A content of the soft-magnetic particles in the magnetic layer is from 35 vol % to 40 vol % with respect to the overall volume of the magnetic layer. The binder is made of polyacrylic rubber or of mixture of polyacrylic rubber and nitrile rubber. The binder binds the soft-magnetic particles to each other. A content of the binder in the magnetic layer is from 35 vol % to 65 vol % with respect to the overall volume of the magnetic layer. The protective layer reinforces the magnetic layer.

First claim

What is claimed is:

1 . A magnetic sheet adapted to be used as a noise reduction member for a cable, wherein:
the magnetic sheet has a width of 5 mm to 15 mm; the magnetic sheet has a magnetic layer and a protective layer; the magnetic layer comprises soft-magnetic particles and a binder; each of the soft-magnetic particles has a flat shape; a content of the soft-magnetic particles in the magnetic layer is from 35 vol % to 40 vol % with respect to the overall volume of the magnetic layer; the binder is made of polyacrylic rubber or of a mixture of polyacrylic rubber and nitrile rubber; the binder binds the soft-magnetic particles to each other; a content of the binder in the magnetic layer is from 35 vol % to 65 vol % with respect to the overall volume of the magnetic layer; the protective layer reinforces the magnetic layer; the magnetic sheet further comprises a metal layer and a first adhesive layer; the metal layer is made of Al or Cu; the metal layer has a thickness of 7 μm or more; and the first adhesive layer adheres the metal layer and the protective layer to each other.

2 . The magnetic sheet as recited in claim 1 , wherein:
the magnetic layer further includes a fire retardant; and a content of the fire retardant in the magnetic layer is 20 vol % or less with respect to the overall volume of the magnetic layer.

3 . The magnetic sheet as recited in claim 1 , wherein the magnetic layer has a thickness of 20 μm to 100 μm.

4 . The magnetic sheet as recited in claim 1 , wherein the soft-magnetic particles have a median particle size D50 from 55 μm to 90 μm, where the median particle size D50 is a size of the soft-magnetic particle at 50 vol % on a cumulative distribution curve relating volume percentage to sizes of the soft-magnetic particles.

5 . The magnetic sheet as recited in claim 4 , wherein:
the soft-magnetic particles have a median particle size D10 from 25 μm to 55 μm, where the median particle size D10 is the size of the soft-magnetic particle at 10 vol % on the cumulative distribution curve relating volume percentage to the sizes of the soft-magnetic particles; and the soft-magnetic particles have a median particle size D90 from 100 μm to 150 μm, where the median particle size D90 is the size of the soft-magnetic particle at 90 vol % on the cumulative distribution curve relating volume percentage to the sizes of the soft-magnetic particles.

6 . The magnetic sheet as recited in claim 1 , wherein:
the magnetic sheet further comprises a second adhesive layer; and the second adhesive layer adheres the magnetic layer and the protective layer to each other.

7 . The magnetic sheet as recited in claim 6 , wherein the second adhesive layer is made of polyether-based adhesive or polyester-based adhesive.

8 . The magnetic sheet as recited in claim 1 , wherein:
the protective layer is made of PET (polyethylene terephthalate); and the protective layer has a thickness of 12 μm or more.

Assignees

• Tokin Corp

Inventors

• Omiya Tadashi
• Abe Masakazu

Classifications

• H01F1/16

  in the form of sheets (H01F1/147 takes precedence) · CPC title

• H01F1/22

  pressed, sintered, or bound together · CPC title

• H01F1/28 Primary

  dispersed or suspended in a bonding agent · CPC title

• H01B7/17

  Protection against damage caused by external factors, e.g. sheaths or armouring · CPC title

• B32B7/12

  using interposed adhesives or interposed materials with bonding properties · CPC title