JP2005104785A - Ferrite powder, composite insulating magnetic composition and electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide ferrite powder which is excellent in handleability and suitable for the manufacture of an electronic component such as a cable having excellent flexibility. <P>SOLUTION: The ferrite powder has an essential component containing iron oxide and at least zinc oxide and having the magnetic permeability of ≥500 as the material/quality characteristics, wherein the volume average particle diameter is 2-40 μm, the content of coarse particles having ≥100 μm particle diameter is ≤5% in the particle size distribution, the compaction density is 3.0-3.8 g/cm<SP>3</SP>and the maximum magnetization is 40-60 Am<SP>2</SP>/kg. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a ferrite powder, a composite insulating magnetic composition, and an electronic component.

  Conventionally, as a noise filter, a ferrite bead core or a clamp filter in which the core is placed in a resin holder is attached to a cable as an EMC functional part, and a technology capable of suppressing noise at 10 to 15 dB at a frequency at which attenuation is desired is known. (See Patent Document 1).

  However, the technique described in Patent Document 1 is heavy because the ferrite core is used in appearance, and even when a clamp filter is used, the cable has a large convex shape (the core portion is thicker than the cable), and the original cable Since the appearance is obviously different, there is a defect that the handling property is impaired.

  Further, there is known a cable in which a signal line and a power line are covered with rubber obtained by kneading 90% or more by weight of ferrite powder having a magnetic permeability of 450 as a material / material characteristic (see Patent Document 2). In the technique of Patent Document 2, the magnetic insulator itself has a magnetic permeability of 15, and can effectively suppress noise.

However, in the technique described in Patent Document 2, since the magnetic properties of the ferrite powder to be used are low, it is necessary to knead a large amount of ferrite powder such as 90% by weight or more into the resin. However, there was a drawback that the replacement time was accelerated. Furthermore, since a large amount of ferrite powder is added, the viscoelasticity is inferior, resulting in a problem that the flexibility of the cable as a product is impaired.
JP 2000-251545 A JP-A-11-250743

  An object of the present invention is a ferrite powder suitable for manufacturing electronic parts such as a cable having good handleability and excellent flexibility, a composite insulating magnetic composition containing the powder, a cable containing the composition, and the like Electronic components.

In order to achieve the above object, according to a first aspect of the present invention,
A ferrite powder having a main component including iron oxide and at least zinc oxide, having a permeability of 500 or more as a material / material property,
A volume average particle diameter of 2 to 40 μm, a particle size distribution of coarse particles of 100 μm or more of 5% or less, a compression density of 3.0 to 3.8 g / cm ³ , and a maximum magnetization of 40 to 60 Am ² / Kg. A ferrite powder is provided.

  According to this invention, the ferrite powder suitable for manufacture of electronic parts, such as a cable which is favorable in handleability and excellent in flexibility, is provided.

  The main component of the ferrite powder is not particularly limited as long as it contains iron oxide and at least zinc oxide. For example, Ni—Zn substantially composed of iron oxide, nickel oxide, zinc oxide, and copper oxide. -Cu system; Mn-Zn-Mg system composed of iron oxide, manganese oxide, zinc oxide and magnesium oxide; Mn-Zn system composed of iron oxide, manganese oxide and zinc oxide;

  In the 1st viewpoint of this invention, it is preferable to employ | adopt the structure which concerns on the 2nd-4th viewpoint shown below.

According to the second aspect,
A ferrite powder having a main component substantially composed of iron oxide, nickel oxide, zinc oxide and copper oxide, and having a permeability of 500 or more as a material / material property,
A volume average particle diameter of 2 to 40 μm, a particle size distribution of coarse particles of 100 μm or more of 5% or less, a compression density of 3.0 to 3.8 g / cm ³ , and a maximum magnetization of 40 to 60 Am ² / Kg. A ferrite powder is provided.

According to the third aspect,
A ferrite powder having a main component substantially composed of iron oxide, manganese oxide, zinc oxide and magnesium oxide, and having a magnetic permeability of 500 or more as a material / material property,
A volume average particle diameter of 2 to 40 μm, a particle size distribution of coarse particles of 100 μm or more of 5% or less, a compression density of 3.0 to 3.8 g / cm ³ , and a maximum magnetization of 40 to 60 Am ² / Kg. A ferrite powder is provided.

According to the fourth aspect,
A ferrite powder having a main component substantially composed of iron oxide, manganese oxide, and zinc oxide and having a permeability of 500 or more as a material / material property,
A volume average particle diameter of 2 to 40 μm, a particle size distribution of coarse particles of 100 μm or more of 5% or less, a compression density of 3.0 to 3.8 g / cm ³ , and a maximum magnetization of 40 to 60 Am ² / Kg. A ferrite powder is provided.

  According to the second to fourth aspects, the ferrite powder includes each component and has desired magnetic characteristics. Further, the volume average particle diameter is adjusted to a predetermined range, and classification is performed so that coarse particles are not included as much as possible. When the ferrite powder obtained by each of these limitations is mixed with at least a resin in a predetermined ratio, it becomes easy to obtain a composite insulating composition in which the ferrite powder is uniformly dispersed in the resin.

  In the said 1st viewpoint, it is good also as taking the structure of each invention which concerns on the 5th-7th viewpoint shown below. By adopting this composition, it is possible to achieve magnetic characteristics having a magnetic permeability of 500 or more as material / material characteristics.

According to the fifth aspect,
A ferrite powder having a main component substantially composed of iron oxide, nickel oxide, zinc oxide and copper oxide,
The content of each oxide in 100 mol% of the main component is 45 to 50 mol% in terms of iron oxide: Fe ₂ O ₃ , 10 to 20 mol% in terms of nickel oxide: NiO, and zinc oxide: 25 to 40 mol% in terms of ZnO, 5 to 10 mol% in terms of copper oxide: CuO, and a particle size in which the volume average particle diameter of 2 to 40 μm and coarse particles of 100 μm or more are 5% or less Ferrite powder having a distribution, a compression density of 3.0 to 3.8 g / cm ³ and a maximum magnetization of 40 to 60 Am ² / Kg is provided.

According to the sixth aspect,
A ferrite powder having a main component substantially composed of iron oxide, manganese oxide, zinc oxide and magnesium oxide,
The content of the oxides of said main component of 100 mole percent, of iron oxide: in terms of _Fe 2 _{O 3} 45 to 50 mol%, manganese oxide: 1 to 10 mol% in terms of MnO, ZnO: 15 to 25 mol% in terms of ZnO, 25 to 35 mol% in terms of magnesium oxide: MgO, and a volume average particle size of 2 to 40 μm and a particle size of 5% or less of coarse particles of 100 μm or more Ferrite powder having a distribution, a compression density of 3.0 to 3.8 g / cm ³ and a maximum magnetization of 40 to 60 Am ² / Kg is provided.

According to the seventh aspect,
A ferrite powder having a main component substantially composed of iron oxide, manganese oxide and zinc oxide,
The content of the oxides of said main component of 100 mole percent, of iron oxide: in terms of _Fe 2 _{O 3} 50-55 mol%, manganese oxide: in terms of _Mn 2 _{O 3} 30 to 40 mol%, Zinc oxide: 5 to 15 mol% in terms of ZnO, and a volume average particle size of 2 to 40 μm, a particle size distribution of 100% or more of coarse particles of 5% or less, and 3.0 to 3.8 g / A ferrite powder having a compression density of cm ³ and a maximum magnetization of 40-60 Am ² / Kg is provided.

  According to the 5th to 7th viewpoints, by setting it as a specific composition range, as a ferrite powder, desired magnetic characteristics are obtained. Further, the volume average particle diameter is adjusted to a predetermined range, and classification is performed so that coarse particles are not included as much as possible. When the ferrite powder obtained by each of these limitations is mixed with at least a resin in a predetermined ratio, it becomes easy to obtain a composite insulating composition in which the ferrite powder is uniformly dispersed in the resin.

  The ferrite powder of the present invention may be indefinite or spherical.

  According to the present invention, a composite insulating magnetic composition comprising any one of the above ferrite powders and at least a resin, wherein the content of each component in 100% by volume of the composition is ferrite powder: 35-60% by volume, A composite insulating magnetic composition having a resin content of 40 to 65% by volume is provided.

  According to this invention, since the ferrite powder used has high magnetic properties, the amount of ferrite powder kneaded can be kept low. As a result, it is possible to provide a composite insulating magnetic composition that is highly flexible and capable of attenuating noise in a target frequency band (50 to 300 MHz).

  According to the present invention, there is provided an electronic component having a composite insulating magnetic layer composed of the above composite insulating magnetic composition, wherein the composite insulating magnetic layer is formed with a thickness of 100 to 400 μm. An electronic component is provided.

  According to this invention, since the magnetic properties of the ferrite powder in the composite insulating magnetic composition are high, the amount of ferrite powder in the composition can be kept low. For this reason, the flexibility of the electronic component obtained can be improved. Regarding the thickness of the composite insulating magnetic layer, flexibility, which is one of the commercial values of the cable, is important in addition to the noise attenuation characteristic which is the original purpose.

  Although it does not specifically limit as an electronic component, The high-speed signal cable etc. which adapted USB and IEEE1394 standards in a personal computer, a digital household appliance, a game machine etc. are illustrated.

  The “permeability” in the present invention means not the permeability measured by the ferrite powder itself, but the permeability of a sintered core obtained by the powder metallurgy method having the same composition, for example, a toroidal core. In order to clarify this point, the present invention uses the phrase “as material / material properties”.

  Since the ferrite powder of the present invention has appropriate magnetic properties and particle size distribution, it can be uniformly mixed with the resin. Further, by controlling the composition of the ferrite powder, the obtained composite insulating magnetic composition is excellent in noise attenuation characteristics in a target frequency band. Further, by controlling the thickness of the composite insulating magnetic composition, it is possible to provide flexibility as a cable, and it is possible to improve the quality as a product.

  That is, according to the present invention, the ferrite powder suitable for the manufacture of electronic parts such as cables having good handleability and excellent flexibility, a composite insulating magnetic composition containing the powder, and the composition Electronic components such as cables can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. put it here,
FIG. 1 is a cross-sectional view showing a high-speed signal cable as an example of an electronic component according to the present invention.
FIG. 2 is a particle size distribution diagram relating to three types of sample 1-2, sample 1-4, and sample 1-6 in the examples.
FIG. 3 is a plan view of a dedicated jig used when evaluating flexibility in the embodiment.
4 is a right side view of FIG.
FIG. 5 is a plan view showing a state where a sample is set and bent in the jig of FIG.
6 is a right side view of FIG.

High-Speed Signal Cable As shown in FIG. 1, a high-speed signal cable 2 as an example of an electronic component according to an embodiment of the present invention has a signal conductor 4 having a substantially circular cross section. A first insulating layer 6 is coated on the outside of the signal conductor 4. A composite insulating magnetic layer 8 is coated on the outside of the first insulating layer 6. A second insulating layer 10 is coated on the outside of the composite insulating magnetic layer 8.

  The signal conducting wire 4 is composed of a signal line, a power supply line, etc., and the diameter thereof is, for example, about 1.5 to 3.0 mm.

  The 1st insulating layer 6 and the 2nd insulating layer 10 are comprised by resin, such as a vinyl chloride, polyethylene, a polypropylene, The thickness is about 300-600 micrometers, for example.

Composite Insulating Magnetic Layer The composite insulating magnetic layer 8 has a thickness of 100 to 400 μm, preferably 150 to 300 μm.

  The composite insulating magnetic layer 8 is composed of the composite insulating magnetic composition of the present invention. This point will be described later.

  The method for forming the composite insulating magnetic layer 8 is not particularly limited. For example, the composite insulating magnetic composition 8 is formed by coating the outer surface of the first insulating layer 6 with a means such as extrusion molding. However, after the composite insulating magnetic composition is formed in a band shape, it may be wound around the outside of the first insulating layer 6.

Composite Insulating Magnetic Composition The composite insulating magnetic composition of the present invention is formed by mixing ferrite powder with at least a resin.

  Content of each component in 100 volume% of compositions is ferrite powder: 35-60 volume%, Preferably it is 40-50 volume%, Resin: 40-65 volume%, Preferably it is 50-60 volume%.

  Although it does not specifically limit as resin contained in a composition, For example, an olefin type thermoplastic resin (polyethylene, polypropylene, etc.) etc. are mentioned.

  The ferrite powder contained in the composition will be described later.

  The composite insulating magnetic composition of the present invention may be formed by mixing ferrite powder, a metal material, and a resin within a range that does not impair the characteristics. Examples of the metal material include an iron silicon chromium alloy, an iron silicon alloy, and an iron nickel alloy.

  The method for producing the composite insulating magnetic composition is not particularly limited. For example, it can be performed by kneading ferrite powder and resin using an extruder.

The ferrite powder contained in the ferrite powder composition is composed of any ferrite powder according to the first to seventh aspects of the present invention.

  The ferrite powder according to the first aspect has a main component including iron oxide and at least zinc oxide, and has a magnetic permeability of 500 or more as a material / material characteristic.

  The ferrite powder according to the second aspect substantially has a main component composed of iron oxide, nickel oxide, zinc oxide and copper oxide, and has a magnetic permeability of 500 or more as material / material characteristics.

  The ferrite powder according to the third aspect substantially has a main component composed of iron oxide, manganese oxide, zinc oxide, and magnesium oxide, and has a magnetic permeability of 500 or more as material / material characteristics.

  The ferrite powder according to the fourth aspect substantially has a main component composed of iron oxide, manganese oxide, and zinc oxide, and has a magnetic permeability of 500 or more as a material / material characteristic.

The ferrite powder according to the fifth aspect has a main component substantially composed of iron oxide, nickel oxide, zinc oxide and copper oxide, and the content of each oxide in 100 mol% of the main component. Is converted to iron oxide: Fe ₂ O ₃ in an amount of 45 to 50 mol%, preferably 48 to 49 mol%, nickel oxide: NiO in an amount of 10 to 20 mol%, preferably 13 to 17 mol% Zinc: 25 to 40 mol%, preferably 25 to 35 mol% in terms of ZnO, and copper oxide: 5 to 10 mol%, preferably 7 to 9 mol%, in terms of CuO.

The ferrite powder according to the sixth aspect has a main component substantially composed of iron oxide, manganese oxide, zinc oxide and magnesium oxide, and the content of each oxide in 100 mol% of the main component. but iron oxide: in terms of _Fe 2 _{O 3} 45 to 50 mol%, preferably 48 to 49 mol%, manganese oxide: 1 to 10 mol% in terms of MnO, preferably 2 to 5 mol%, oxide Zinc: 15 to 25 mol% in terms of ZnO, preferably 18 to 22 mol%, and magnesium oxide: 25 to 35 mol% in terms of MgO, preferably 28 to 32 mol%.

The ferrite powder according to the seventh aspect substantially has a main component composed of iron oxide, manganese oxide, and zinc oxide, and the content of each oxide in 100 mol% of the main component is oxidized. iron: in terms of _Fe 2 _{O 3} 50-55 mol%, preferably 52 to 54 mol%, manganese oxide: in terms of _Mn 2 _{O 3} 30 to 40 mol%, preferably 33-38 mol%, oxide Zinc: 5 to 15 mol%, preferably 8 to 12 mol% in terms of ZnO.

The ferrite powders according to the above first to seventh aspects all have a volume average particle diameter of 2 to 40 μm, preferably 10 to 30 μm, and coarse particles of 100 μm or more are 5% or less, preferably 1% or less. Distribution, a compression density of 3.0 to 3.8 g / cm ³ , preferably 3.2 to 3.5 g / cm ³ , and a maximum magnetization of 40 to 60 Am ² / Kg, preferably 45 to 55 Am ² / Kg Have.

By specifying the compression density to 3.0 to 3.8 g / cm ³ , the blended state of the ferrite powder at the time of compounding can be stabilized. If the compression density is too small, the ferrite powder contains hollow particles even if the particle size of the ferrite powder is large, and the damping characteristics tend to be inferior. When the compression density is too large, the particle size of the ferrite powder is large, so that the flexibility of the composite insulating magnetic composition using the ferrite powder tends to be inferior. If the maximum magnetization is too small, there is a tendency to be insufficiently burned, the magnetic permeability is lowered, and desired magnetic properties cannot be obtained. If the maximum magnetization is too large, there is a tendency to burn too much, the magnetic permeability decreases, and desired magnetic properties cannot be obtained. If the volume average particle size, coarse particles, and magnetic properties (permeability) as the material / material properties are outside the above range, the noise attenuation characteristics of the cable will be inferior, and the noise in the target frequency band that is the original purpose Attenuation cannot be satisfied.

The ferrite powder of the present invention may have various subcomponents in addition to the main component. Examples of subcomponents include SiO ₂ and Bi ₂ O ₃ . The content of the subcomponent is preferably about 0.1 to 0.5% by weight in terms of oxide in the ferrite powder.

  The ferrite powder of the present invention may contain oxides of unavoidable impurity elements in addition to the main component and subcomponents.

Method for Producing Ferrite Powder An example of the method for producing the ferrite powder of the present invention will be described.

First Method (1) First, starting materials are weighed and mixed so as to have a predetermined composition ratio to obtain a raw material mixture. Examples of the mixing method include wet mixing using a ball mill and dry mixing using a dry mixer. It is preferable to use a starting material having an average particle size of 0.1 to 3 μm.

The raw material mixture is iron oxide (α-Fe ₂ O ₃ ), zinc oxide (ZnO), nickel oxide (NiO), magnesium oxide (MgO), manganese oxide (Mn ₂ O ₃ , Mn0), or the above oxide by firing. The main component raw material which consists of an oxide of the said exemplary metal is preferably contained. The raw material mixture may contain subcomponent raw materials. Examples of the oxide that is formed by firing include simple metals, carbonates, hydroxides, halides, and the like. Each raw material is mixed so as to have the above-mentioned quantitative ratio as the final composition of ferrite.

  The raw material mixture may contain inevitable impurity elements in the raw material. Examples of such elements include B, Al, Si, P, Ca, Cr, Co, Na, K, S, and Cl. In order to suppress the influence on the magnetic properties, the weight ratio of these elements to the entire composition is preferably 500 ppm or less.

  (2) Next, the raw material mixture is calcined to obtain a calcined material. Calcining causes thermal decomposition of raw materials, homogenization of ingredients, formation of ferrite, disappearance of ultrafine powder due to sintering and grain growth to an appropriate particle size, and converts the raw material mixture into a form suitable for the subsequent process. Done for. Such calcination is preferably performed at a temperature of 800 to 1100 ° C. for about 1 to 3 hours. The calcination may be performed in the atmosphere (air) or may be performed in an atmosphere having a higher oxygen partial pressure than in the atmosphere. In addition, when a subcomponent is included in ferrite, the main component raw material and the subcomponent raw material may be mixed before calcination or after calcination.

  (3) Next, the calcined material is pulverized to obtain a pulverized material. The pulverization is performed in order to produce a powder having appropriate sinterability by destroying the aggregation of the calcined material. When the calcined material forms a large lump, wet pulverization is performed using a ball mill or an attritor after coarse pulverization. The wet pulverization is performed until the average particle size of the calcined material is preferably about 0.5 to 2 μm.

  (4) Next, the pulverized material is granulated (granulate) to obtain a granulated product. The granulation is performed in order to convert the pulverized material into aggregated particles having an appropriate size and convert it into a form suitable for molding. Examples of such a granulation method include a pressure granulation method and a spray drying method. The spray drying method is a method in which a commonly used binder such as polyvinyl alcohol is added to the pulverized material, and then atomized in a spray dryer and dried.

  (5) Next, after the granulated product is formed into a predetermined shape, main firing is performed to obtain a sintered body. This firing is performed in order to obtain a dense sintered body by causing sintering in which the powder adheres at a temperature below the melting point between the powder particles of the molded body containing many voids. Such firing is preferably performed at a temperature of 900 to 1300 ° C. for about 10 to 15 hours. The main calcination may be performed in the atmosphere (air) or in an atmosphere having a higher oxygen partial pressure than in the atmosphere.

  (6) Next, the obtained sintered body is subjected to, for example, dry pulverization, and particle size adjustment is performed with a vibrating sieve using a mesh having a mesh size so as to obtain a target particle size distribution, and coarse particles of 100 μm or more are obtained. The volume average particle diameter D50 is set to 1 to 50 μm.

  Through such steps, an irregularly shaped ferrite powder is produced.

Second Method A spherical ferrite powder can also be produced as follows.

  (1-3) First, the raw material mixture is prepared, calcined, and pulverized in the same manner as described above.

  (4 ′) Next, water and a binder are mixed with the pulverized material to prepare a slurry having a concentration of about 55 to 70%, and then a disk spray type (¢ 80 to 100 mm) is used for the slurry. It is sprayed and dried under the condition that the disk rotation speed is higher than the normal rotation speed (6000 to 8000 rpm) (14000 to 17000 rpm) to obtain a granulated product containing a spherical powder.

  (5) Next, in the same manner as described above, the granulated product is molded into a predetermined shape, and then subjected to main firing to obtain a sintered body.

  (6 ′) Next, the obtained sintered body is sized with a vibrating sieve using a mesh having an opening size that achieves a target particle size distribution, and coarse particles of 100 μm or more become 5% or less. Thus, the volume average particle diameter D50 is set to 1 to 50 μm.

  Through these steps, spherical ferrite powder is produced.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment at all, Of course, in the range which does not deviate from the summary of this invention, it can implement in various aspects. .

  Next, the present invention will be described in more detail with reference to examples that further embody the embodiment of the present invention. However, the present invention is not limited to only these examples.

First, Fe ₂ O ₃ , ZnO, NiO, CuO, MnO, Mn ₂ O ₃ and MgO were prepared as starting materials.

Next, the powder of each starting material is
As the Ni-Zn-Cu-based ferrite (sample _{1-1~1-8), Fe 2 O 3:} 49mol%, NiO: 13mol%, ZnO: 30mol%, CuO: 8mol%;
As the Ni-Zn-Cu-based ferrite (sample _{2-4,2-4-1~2-4-5), Fe 2 O 3:} 48mol%, NiO: 17mol%, ZnO: 26mol%, CuO: 9mol%;
As Mg—Zn—Mn ferrite (Sample 3-4-1), Fe ₂ O ₃ : 45 mol%, MnO: 6 mol%, ZnO: 18 mol%, MgO: 31 mol%;
As Mg—Zn—Mn ferrite (sample 3-4-2), Fe ₂ O ₃ : 48 mol%, MnO: 2 mol%, ZnO: 19 mol%, MgO: 31 mol%;
As Mn-Zn ferrite (sample _{4-4), Fe 2 O 3:} 53mol%, Mn 3 O 4: 37mol%, ZnO: 10mol%;
Then, the mixture was wet mixed with a ball mill for 5 hours to obtain a raw material mixture.

  Next, the obtained raw material mixture was calcined in air at 900 ° C. for 2 hours to obtain a calcined material, and then wet pulverized with a ball mill for 20 hours to obtain a pulverized material.

  Next, after drying the pulverized material, 1.0% by weight of polyvinyl alcohol as a binder was added to 100% by weight of the pulverized material, and granulated to obtain a granulated product, which was added at a pressure of 100 kPa. A compact was obtained by pressure molding.

  Next, each of these molded bodies was baked at 1100 ° C. for 12 hours in the air except for the sample 4-4 to obtain a sintered body. Sample 4-4 was fired at 1300 ° C. for 10 hours in an atmosphere firing (oxygen concentration adjustment).

  Next, each sintered compact is dry-pulverized and sized with a vibrating sieve using a mesh with an opening size that makes the target particle size distribution, so that coarse particles of 100 μm or more become 5% or less. An irregularly shaped ferrite powder was prepared so that the volume average particle diameter D50 was 1 to 50 μm (all samples except Sample 1-6).

  A spherical ferrite powder was also produced (Sample 1-6). 59.5 parts by mass of the pulverized material after calcining, 39.8 parts by mass of water, 0.5 parts by mass of polyvinyl alcohol, and 0.2 parts by mass of a dispersant are mixed in a wet pulverization mixer. A slurry with a concentration of 60% was prepared. Next, a disc spray type (¢ 80 to 100 mm) is used for the prepared slurry, and the disc rotation speed is rotated at 15000 rpm, which is higher than usual, and sprayed and dried. A granulated product containing was obtained. Next, in the same manner as described above, the granulated product was molded, and then main firing was performed to obtain a sintered body. Next, the obtained sintered body is sized with a vibrating sieve using a mesh having an opening size so as to have a target particle size distribution, so that coarse particles of 100 μm or more are 5% or less, A spherical ferrite powder was prepared so that the average particle diameter D50 was 1 to 50 μm.

  FIG. 2 shows particle size distributions for three types of sample 1-2 (D50 = 2 μm), sample 1-4 (D50 = 15 μm), and sample 1-6 (D50 = 30 μm).

  The compression density, magnetic permeability (μi), and maximum magnetization (σm) as the material / material characteristics of each ferrite powder obtained were determined.

The compression density is calculated by putting a certain amount of ferrite powder in a compression density measuring mold (cylinder type with a diameter of 25 mm) and dividing the weight of the ferrite powder when a pressure of 1.0 ton / cm ² is applied from the upper mold by the ferrite powder volume. (Unit: g / cm ³ ).

  The magnetic permeability (μi) was determined by measuring under the condition of a direct current magnetic field H = 1000 A / m at a frequency of 1 MHz and H = 0.4 A / m (no unit).

The maximum magnetization (σm) was determined by applying a magnetic field of 1 kOe (= about 7.96 × 10 ⁴ A / m) to 50 mg of ferrite powder with a VSM measuring device (vibrating sample magnetometer) (unit: : Am ² / Kg).

  Next, the obtained ferrite powder and polypropylene are mixed in a volume ratio of 30 to 70%, and are composed of a composite insulating magnetic composition of length 100 mm × width 30 mm × thickness 80 to 500 μm by blade control. A composite insulating magnetic layer (magnetic layer sample) was prepared. As shown in FIGS. 3 and 4, the obtained magnetic layer sample 24 is set in the dedicated jig 20, and the flexibility when it is repeatedly bent 100 times as shown in FIGS. 5 and 6 is evaluated. The results were as follows: “O” for no abnormality, “△” for crack occurrence, and “x” for fracture.

表１〜２に示すように、本発明の範囲外である値を含む試料１−１、１−８、２−４−１、２−４−５、３−４−１では、フレキシビリティーや放射ノイズの減衰特性のいずれかが悪化することが確認できた。 In addition, when the magnetic layer sample obtained is covered with the signal line and power line of the USB cable, the attenuation characteristic of the radiation noise in the target frequency band is evaluated, and the attenuation level exceeds 10 dB Was set as “3” as the best evaluation score, 5 to 10 dB as “2” as the next best evaluation score, and “1” when less than 5 dB. The results are shown in Tables 1-2. In each table, portions marked with “*” are out of the scope of the present invention.

As shown in Tables 1-2, samples 1-1, 1-8, 2-4-1, 2-4-5, 3-4-1 containing values that are outside the scope of the present invention are flexible. It was confirmed that either the attenuation characteristics of radiation noise or radiated noise deteriorated.

  On the other hand, in the sample within the scope of the present invention, since the ferrite powder has sufficient magnetic properties, the filling rate into the composition can be kept low, thereby ensuring flexibility and damping. It was confirmed that the characteristics could be improved.

FIG. 1 is a sectional view showing a high-speed signal cable as an example of an electronic component according to the present invention. FIG. 2 is a particle size distribution diagram for three types of sample 1-2, sample 1-4, and sample 1-6 in the example. FIG. 3 is a plan view of a dedicated jig used when evaluating flexibility in the embodiment. FIG. 4 is a right side view of FIG. FIG. 5 is a plan view showing a state in which a sample is set on the jig of FIG. 3 and bent. FIG. 6 is a right side view of FIG.

Explanation of symbols

2 ... High-speed signal cable 4 ... Signal conductor 6 ... First insulating layer 8 ... Composite insulating magnetic layer 10 ... Second insulating layer 20 ... Dedicated jig 22 ... Mounting plate 24 ... Magnetic layer sample 26 ... Sample restraining plate 28 ... Hinge

Claims (9)

A ferrite powder having a main component including iron oxide and at least zinc oxide, having a permeability of 500 or more as a material / material property,
A volume average particle diameter of 2 to 40 μm, a particle size distribution of coarse particles of 100 μm or more of 5% or less, a compression density of 3.0 to 3.8 g / cm ³ , and a maximum magnetization of 40 to 60 Am ² / Kg. , Having ferrite powder. A ferrite powder having a main component substantially composed of iron oxide, nickel oxide, zinc oxide and copper oxide, and having a permeability of 500 or more as a material / material property,
A volume average particle diameter of 2 to 40 μm, a particle size distribution of coarse particles of 100 μm or more of 5% or less, a compression density of 3.0 to 3.8 g / cm ³ , and a maximum magnetization of 40 to 60 Am ² / Kg. , Having ferrite powder. A ferrite powder having a main component substantially composed of iron oxide, manganese oxide, zinc oxide and magnesium oxide, and having a magnetic permeability of 500 or more as a material / material property,
A volume average particle diameter of 2 to 40 μm, a particle size distribution of coarse particles of 100 μm or more of 5% or less, a compression density of 3.0 to 3.8 g / cm ³ , and a maximum magnetization of 40 to 60 Am ² / Kg. , Having ferrite powder. A ferrite powder having a main component substantially composed of iron oxide, manganese oxide, and zinc oxide and having a permeability of 500 or more as a material / material property,
A volume average particle diameter of 2 to 40 μm, a particle size distribution of coarse particles of 100 μm or more of 5% or less, a compression density of 3.0 to 3.8 g / cm ³ , and a maximum magnetization of 40 to 60 Am ² / Kg. , Having ferrite powder. A ferrite powder having a main component substantially composed of iron oxide, nickel oxide, zinc oxide and copper oxide,
The content of each oxide in 100 mol% of the main component is 45 to 50 mol% in terms of iron oxide: Fe ₂ O ₃ , 10 to 20 mol% in terms of nickel oxide: NiO, and zinc oxide: 25 to 40 mol% in terms of ZnO, 5 to 10 mol% in terms of copper oxide: CuO, and a particle size in which the volume average particle diameter of 2 to 40 μm and coarse particles of 100 μm or more are 5% or less A ferrite powder having a distribution, a compression density of 3.0 to 3.8 g / cm ³ and a maximum magnetization of 40 to 60 Am ² / Kg. A ferrite powder having a main component substantially composed of iron oxide, manganese oxide, zinc oxide and magnesium oxide,
The content of the oxides of said main component of 100 mole percent, of iron oxide: in terms of _Fe 2 _{O 3} 45 to 50 mol%, manganese oxide: 1 to 10 mol% in terms of MnO, ZnO: 15 to 25 mol% in terms of ZnO, 25 to 35 mol% in terms of magnesium oxide: MgO, and a volume average particle size of 2 to 40 μm and a particle size of 5% or less of coarse particles of 100 μm or more A ferrite powder having a distribution, a compression density of 3.0 to 3.8 g / cm ³ and a maximum magnetization of 40 to 60 Am ² / Kg. A ferrite powder having a main component substantially composed of iron oxide, manganese oxide and zinc oxide,
The content of the oxides of said main component of 100 mole percent, of iron oxide: in terms of _Fe 2 _{O 3} 50-55 mol%, manganese oxide: in terms of _Mn 2 _{O 3} 30 to 40 mol%, Zinc oxide: 5 to 15 mol% in terms of ZnO, and a volume average particle size of 2 to 40 μm, a particle size distribution of 100% or more of coarse particles of 5% or less, and 3.0 to 3.8 g / A ferrite powder having a compression density of cm ³ and a maximum magnetization of 40 to 60 Am ² / Kg. A composite insulating magnetic composition comprising the ferrite powder according to claim 1 and at least a resin,
The composite insulation magnetic composition whose content of each component in 100 volume% of this composition is ferrite powder: 35-60 volume%, resin: 40-65 volume%. An electronic component having a composite insulating magnetic layer composed of the composite insulating magnetic composition according to claim 8,
An electronic component, wherein the composite insulating magnetic layer is formed with a thickness of 100 to 400 μm.

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