# US 12,014,854 B2 · Magnetic paste

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- Number: US 12,014,854 B2
- Document ID: US12014854B2
- Status: Granted
- Kind: B2
- Application number: 17/224,815
- Filed: 2021-04-07
- Published: 2021-07-22
- Granted: 2024-06-18
- Earliest claimed: 2018-10-10
- Assignees: Ajinomoto Co., Inc.
- Applicants: Ajinomoto Co., Inc.
- Inventors: Ichiro Oura; Tatsuya Homma; Masanori Yoda; Takayuki Tanaka
- Web page: https://patentgrep.com/patent/US12014854B2

## CPC

- H01F 1/37: in a bonding agent
- H01F 17/0006: {Printed inductances (printed coils for dynamo-electric machines H02K3/26; printed circuits H05K)}
- H01F 17/04: with magnetic core
- H01F 41/045: {Trimming}
- H01F 41/14: for applying magnetic films to substrates
- H01F 2017/0066: {with a magnetic layer}
- H01F 2017/048: {with encapsulating core, e.g. made of resin and magnetic powder}
- H05K 1/165: {incorporating printed inductors}
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

Magnetic pastes which include a magnetic powder (A) and a binder resin (B), in which, in the particle diameter distribution of the component (A), the 10% particle diameter (D10) is 0.2 μm or larger and 2.0 μm or smaller, the 50% particle diameter (D50) is 2.0 μm or larger and 4.3 μm or smaller, and the 90% particle diameter (D90) is 4.3 μm or larger and 8.5 μm or smaller, suppress the magnetic powder from being unevenly distributed, and are useful for forming inductor elements and circuit boards.

## Claims

### Claim 1

A magnetic paste, comprising:
(A) at least one magnetic powder; and
(B) at least one binder resin (B), wherein
in a particle diameter distribution of said at least one magnetic powder (A), a 10% particle diameter (D10) is 0.2 μm or larger and 2.0 μm or smaller, a 50% particle diameter (D50) is 2.0 μm or larger and 4.3 μm or smaller, and a 90% particle diameter (D90) is 4.3 μm or larger and 8.5 μm or smaller.

### Claim 2 (depends on 1)

The magnetic paste according to claim 1, wherein said at least one binder resin (B) comprises an epoxy resin.

### Claim 3 (depends on 1)

The magnetic paste according to claim 1, wherein said at least one magnetic powder (A) is soft magnetic powder.

### Claim 4 (depends on 1)

The magnetic paste according to claim 1, wherein the magnetic powder (A) is iron oxide powder.

### Claim 5 (depends on 4)

The magnetic paste according to claim 4, wherein said iron oxide powder is ferrite containing at least one element selected from the group consisting of Ni, Cu, Mn, and Zn.

### Claim 6 (depends on 1)

The magnetic paste according to claim 1, wherein said at least one magnetic powder (A) is Fe—Mn-based ferrite.

### Claim 7 (depends on 6)

The magnetic paste according to claim 6, wherein said Mn in said Fe—Mn-based ferrite is present in an amount of 3.0% by mass or higher and 15% by mass or lower.

### Claim 8 (depends on 1)

The magnetic paste according to claim 1, wherein said at least one magnetic powder (A) is present in an amount of 60% by mass or higher with respect to 100% by mass of non-volatile components in said magnetic paste.

### Claim 9 (depends on 1)

The magnetic paste according to claim 1, wherein (D90−D10)/D50 is 2.5 or less.

### Claim 10 (depends on 1)

An inductor element, comprising a magnetic layer that is a cured product of a magnetic paste according to claim 1.

### Claim 11 (depends on 10)

A circuit substrate, comprising a inductor element according to claim 10.