Ferrite powder, resin composition, and molded body

Abstract

The ferrite powder of the present invention is a ferrite powder containing a plurality of ferrite particles, wherein the ferrite particles each are a single crystal body having an average particle diameter of 1-2,000 nm, and have a polyhedron shape, and wherein the ferrite particles each contain 2.0-10.0 mass% of Sr, and 55.0-70.0 mass% of Fe.

Description

technical field

[0001] The present invention relates to ferrite powder, resin composition and molded body. Background technique

[0002] For the production of magnetic recording media, generally, a dispersion liquid in which magnetic powder is dispersed is used (for example, refer to Patent Documents 1 and 2).

[0003] However, conventionally, it has been difficult to make the dispersibility of the magnetic powder in the dispersion liquid excellent. In addition, when the dispersibility of the magnetic powder in the dispersion liquid is to be improved, there occurs a problem that the magnetic properties of the magnetic powder decrease (in particular, the coercive force decreases).

[0004] In addition, the same problem also exists in the magnetic ink in which the magnetic powder is dispersed.

[0005] prior art literature

[0006] patent documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2013-211316

[0008] Patent Document 2: Japanese Patent Laid-Open N...

Examples

preparation example Construction

[0098] As an example of the preparation method of a ferrite raw material (granulation), the following methods are mentioned. That is, first, Fe raw material and Sr raw material are weighed in appropriate amounts to make it into a desired ferrite component, and then pulverized by adding water to prepare a slurry. Then, the prepared slurry is granulated with a spray dryer, and if necessary, pulverized and classified to prepare a granulated product having a predetermined particle diameter.

[0099] Examples of the classification method include air classification, screen filtration, sedimentation, and classification using various sieves.

[0100] Although the average particle diameter of the granulated material is not particularly limited, it is preferably not less than 0.5 μm and not more than 30 μm.

[0101] The average particle diameter can be obtained, for example, by measuring the particle diameter D50 at which the cumulative particle size distribution on a volume basis is 5...

Embodiment 1

[0178] First, the molar ratio of Fe 2 o 3 / SrCO 3 = 5.75 ratio to measure iron oxide (Fe 2 o 3 ) and strontium carbonate (SrCO 3 ), and mixed, water was added thereto, and pulverized to prepare a slurry with a solid content of 50% by mass. Next, the prepared slurry was granulated with a spray dryer, and classified with a gyro shifter and a turbo classifier to prepare a granulated product with an average particle diameter of 15 μm.

[0179] Next, pass a 10Nm 3 / hour supply propane at 35Nm 3 Oxygen is supplied per hour, and the conveying speed of the granulated matter is about 40m / s, and the temperature is 2000°C, and thermal spraying is carried out to ferrite it, and then, it is carried by the air flow of the air supply to be transported, thereby rapidly cooling it in the atmosphere. At this time, since thermal spraying is performed while making the granulated material flow continuously, the particles after thermal spraying and rapid cooling are not bonded to each othe...

Embodiment 2、3

[0183] Ferrite powder was produced in the same manner as in Example 1 above, except that the mixing ratios of iron oxide and strontium carbonate were changed as described in Table 1 below.

technical field

[0001] The present invention relates to ferrite powder, resin composition and molded body. Background technique

[0002] For the production of magnetic recording media, generally, a dispersion liquid in which magnetic powder is dispersed is used (for example, refer to Patent Documents 1 and 2).

[0003] However, conventionally, it has been difficult to make the dispersibility of the magnetic powder in the dispersion liquid excellent. In addition, when the dispersibility of the magnetic powder in the dispersion liquid is to be improved, there occurs a problem that the magnetic properties of the magnetic powder decrease (in particular, the coercive force decreases).

[0004] In addition, the same problem also exists in the magnetic ink in which the magnetic powder is dispersed.

[0005] prior art literature

[0006] patent documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2013-211316

[0008] Patent Document 2: Japanese Patent Laid-Open N...

Examples

preparation example Construction

[0098] As an example of the preparation method of a ferrite raw material (granulation), the following methods are mentioned. That is, first, Fe raw material and Sr raw material are weighed in appropriate amounts to make it into a desired ferrite component, and then pulverized by adding water to prepare a slurry. Then, the prepared slurry is granulated with a spray dryer, and if necessary, pulverized and classified to prepare a granulated product having a predetermined particle diameter.

[0099] Examples of the classification method include air classification, screen filtration, sedimentation, and classification using various sieves.

[0100] Although the average particle diameter of the granulated material is not particularly limited, it is preferably not less than 0.5 μm and not more than 30 μm.

[0101] The average particle diameter can be obtained, for example, by measuring the particle diameter D50 at which the cumulative particle size distribution on a volume basis is 5...

Embodiment 1

[0178] First, the molar ratio of Fe 2 o 3 / SrCO 3 = 5.75 ratio to measure iron oxide (Fe 2 o 3 ) and strontium carbonate (SrCO 3 ), and mixed, water was added thereto, and pulverized to prepare a slurry with a solid content of 50% by mass. Next, the prepared slurry was granulated with a spray dryer, and classified with a gyro shifter and a turbo classifier to prepare a granulated product with an average particle diameter of 15 μm.

[0179] Next, pass a 10Nm 3 / hour supply propane at 35Nm 3 Oxygen is supplied per hour, and the conveying speed of the granulated matter is about 40m / s, and the temperature is 2000°C, and thermal spraying is carried out to ferrite it, and then, it is carried by the air flow of the air supply to be transported, thereby rapidly cooling it in the atmosphere. At this time, since thermal spraying is performed while making the granulated material flow continuously, the particles after thermal spraying and rapid cooling are not bonded to each othe...

Embodiment 2、3

[0183] Ferrite powder was produced in the same manner as in Example 1 above, except that the mixing ratios of iron oxide and strontium carbonate were changed as described in Table 1 below.

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