Radio wave absorbing composition and radio wave absorber

Patent metadata

Field	Value
Publication number	US-12426224-B2
Application number	US-202217666894-A
Country	US
Kind code	B2
Filing date	Feb 8, 2022
Priority date	Aug 9, 2019
Publication date	Sep 23, 2025
Grant date	Sep 23, 2025

Abstract

There is provided a radio wave absorbing composition containing a magnetic powder and a binder. There is also provided a radio wave absorber containing a magnetic powder and a binder. The magnetic powder is a powder of a substitution-type hexagonal ferrite subjected to surface treatment with a surface treatment agent, and the binder is a polyamide.

First claim

What is claimed is:

1. A radio wave absorbing composition comprising:
a magnetic powder; and
a binder,
wherein the magnetic powder is a powder of a substitution-type hexagonal ferrite subjected to surface treatment with a surface treatment agent,
the binder is a polyamide, and
the substitution-type hexagonal ferrite has a constitution represented by General Formula 1,
General Formula 1: AFe (12-x) Al x O 19
in General Formula 1, A represents one or more kinds of atoms selected from the group consisting of Sr, Ba, Ca, and Pb, and x satisfies 1.50≤x≤8.00.

2. The radio wave absorbing composition according to claim 1 ,
wherein the substitution-type hexagonal ferrite is a substitution-type hexagonal strontium ferrite.

3. The radio wave absorbing composition according to claim 1 ,
wherein the surface treatment agent is one or more compounds selected from the group consisting of a silicon-based compound and a titanium-based compound.

4. The radio wave absorbing composition according to claim 1 ,
wherein the surface treatment agent is a silicon-based compound.

5. The radio wave absorbing composition according to claim 1 ,
wherein the surface treatment agent is a silicon-based compound represented by General Formula 2,
(X-L) m -Si—Z 4-m   General Formula 2:

in General Formula 2,
X represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an alicyclic group, a heterocyclic group, a hydroxy group, an acrylamide group, a sulfanyl group, an isocyanate group, a thiocyanate group, a ureido group, a cyano group, an acid anhydride group, an azide group, a carboxy group, an acyl group, a thiocarbamoyl group, a phosphate group, a phosphanyl group, a sulfonic acid group, or a sulfamoyl group,
L represents one divalent group or one bond, selected from the group consisting of a single bond, an alkylene group, an alkenylene group, an alkynylene group, an arylene group, —O—, —S—, —NR a , an ester bond, a thioester bond, an amide bond, a thioamide bond, and a sulfonyl group, or a divalent group or a bond, obtained by combining two or more of these,
R a represents a hydrogen atom or a substituent,
Z represents a hydroxy group, an alkoxy group, or an alkyl group, and
m is an integer in a range of 1 to 3.

6. The radio wave absorbing composition according to claim 5 ,
wherein in General Formula 2, m is 1, and X represents an alkenyl group or a heterocyclic group, or
m is 2 or 3, and a plurality of X's included in General Formula 2 each independently represent an alkenyl group or a heterocyclic group.

7. The radio wave absorbing composition according to claim 5 ,
wherein in General Formula 2, m is 1, and X represents an acyl group, an acrylamide group, or a heterocyclic group, or
m is 2 or 3, and a plurality of X's included in General Formula 2 each independently represent an acyl group, an acrylamide group, or a heterocyclic group,
where the acyl group is a (meth)acryloyl group, and the heterocyclic group is an epoxy group.

8. The radio wave absorbing composition according to claim 5 ,
wherein in General Formula 2, X represents a heterocyclic group, and the heterocyclic group is an epoxy group.

9. The radio wave absorbing composition according to claim 8 ,
wherein in General Formula 2, L includes an alkylene group having 4 to 12 carbon atoms.

10. The radio wave absorbing composition according to claim 1 ,
wherein the surface treatment agent is a titanium-based compound represented by General Formula 3,
R 1 n —Ti—(OR 2 ) 4-n   General Formula 3:

in General Formula 3,
R 1 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, an aryl group, or an unsaturated aliphatic group,
R 2 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, an alkenyl group, an aryl group, a phosphonate group, or —SO 2 R S ,
R S represents a substituent, and
n is an integer in a range of 0 to 3.

11. The radio wave absorbing composition according to claim 10 ,
wherein the titanium-based compound represented by General Formula 3 contains one or more kinds of atoms selected from the group consisting of N, P, and S.

12. The radio wave absorbing composition according to claim 1 ,
wherein the polyamide is one or more polyamides selected from the group consisting of a polyamide 46, a polyamide 6, a polyamide 66, a polyamide 610, a polyamide 612, a polyamide 1010, a polyamide 1012, a polyamide 11, an aromatic polyamide, a polyamide elastomer, and an amorphous polyamide.

13. The radio wave absorbing composition according to claim 1 ,
wherein the polyamide is one or more polyamides selected from the group consisting of a polyamide 9T, a polyamide 11, a polyamide elastomer, and an amorphous polyamide.

14. A radio wave absorber comprising:
a magnetic powder; and
a binder,
wherein the magnetic powder is a powder of a substitution-type hexagonal ferrite subjected to surface treatment with a surface treatment agent,
the binder is a polyamide, and
the polyamide is one or more polyamides selected from the group consisting of a polyamide 9T, a polyamide 11, a polyamide elastomer, and an amorphous polyamide.

15. The radio wave absorber according to claim 14 ,
wherein the surface treatment agent is a silicon-based compound represented by General Formula 2,
(X-L) m -Si—Z 4-m   General Formula 2:

in General Formula 2,
X represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an alicyclic group, a heterocyclic group, a hydroxy group, an acrylamide group, a sulfanyl group, an isocyanate group, a thiocyanate group, a ureido group, a cyano group, an acid anhydride group, an azide group, a carboxy group, an acyl group, a thiocarbamoyl group, a phosphate group, a phosphanyl group, a sulfonic acid group, or a sulfamoyl group,
L represents one divalent group or one bond, selected from the group consisting of a single bond, an alkylene group, an alkenylene group, an alkynylene group, an arylene group, —O—, —S—, —NR a —, an ester bond, a thioester bond, an amide bond, a thioamide bond, and a sulfonyl group, or a divalent group or a bond, obtained by combining two or more of these,
R a represents a hydrogen atom or a substituent,
Z represents a hydroxy group, an alkoxy group, or an alkyl group, and
m is an integer in a range of 1 to 3.

16. The radio wave absorber according to claim 14 ,
wherein the surface treatment agent is a titanium-based compound represented by General Formula 3,
R 1 n —Ti—(OR 2 ) 4-n   General Formula 3:

in General Formula 3,
R 1 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, an aryl group, or an unsaturated aliphatic group,
R 2 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, an alkenyl group, an aryl group, a phosphonate group, or —SO 2 R S ,
R S represents a substituent, and
n is an integer in a range of 0 to 3.

17. The radio wave absorber according to claim 16 ,
wherein the titanium-based compound represented by General Formula 3 contains one or more kinds of atoms selected from the group consisting of N, P, and S.

18. The radio wave absorber according to claim 14 ,
wherein the polyamide is one or more polyamides selected from the group consisting of a polyamide 46, a polyamide 6, a polyamide 66, a polyamide 610, a polyamide 612, a polyamide 1010, a polyamide 1012, a polyamide 11, an aromatic polyamide, a polyamide elastomer, and an amorphous polyamide.

19. A radio wave absorber comprising:
a magnetic powder; and
a bi

Assignees

• Fujifilm Corp

Inventors

• Nakai Yoshihiro
• Hashimoto Hirokazu

Classifications

• H05K9/0075

  Magnetic shielding materials · CPC title

• C08K9/06

  with silicon-containing compounds · CPC title

• C08K9/04

  Ingredients treated with organic substances {(treated with macromolecular compounds C08K9/08)} · CPC title

• H01F1/113

  in a bonding agent · CPC title

• C08K2201/01

  Magnetic additives · CPC title