KR102548558B1 - Soft magnetic metal flat powder, resin composite sheet using the same, and resin composite compound for molding processing - Google Patents

Abstract

A soft magnetic metal flat powder having a high magnetic permeability and having an adjusted temperature coefficient of magnetic permeability, a resin composite sheet using the material, and a resin composite composition for molding. The temperature coefficient K of magnetic permeability of the Fe-Al-Si flat powder of soft magnetic metal satisfies the following formula (1) (2) (3) in the range of -40 ° C to 85 ° C, and the coercive force is 70 A / m or less Soft magnetic metal flat powder characterized by: K = (μ (0 ℃) - μ (-40 ℃)) / μ (-40 ℃) > 0 (1) K = (μ (40 ℃) - μ (0 ℃) ))/μ(0℃) > 0 (2) K = (μ(85℃) - μ(40℃))/μ(40℃) > 0 (3) K: temperature coefficient, μ: magnetic permeability (μ' : real permeability, μ": imaginary permeability). In addition, a resin composite sheet made of the soft magnetic metal flat powder and a resin and having a coercive force of 80 A/m or less. Resin composite for injection molding and extrusion molding composition.

Description

Soft magnetic metal flat powder, resin composite sheet using the same, and resin composite compound for molding processing

The present invention relates to noise suppression components and electromagnetic induction used to prevent leakage of unnecessary electromagnetic waves generated from communication devices and various electronic devices to the outside, interference between internal circuits, and malfunctions caused by external electromagnetic waves. It relates to a soft magnetic metal flat powder used for pen input of a mobile device using a pen or a magnetic shield part used in a non-contact charging module, a resin composite sheet using the same, and a resin composite composition for molding.

Unnecessary electromagnetic waves are generated from communication devices and various electronic devices, and device malfunction or communication failure due to external and internal interference has become a problem, and various countermeasures have been taken. there is.

In addition, as communication devices and various electronic devices are made thinner and smaller, and the packaging density of electronic components increases dramatically, problems caused by electromagnetic interference between components and between circuit boards frequently occur, and electronic components for noise countermeasures and flexible magnets A sheet (resin composite sheet) is used.

On the other hand, effective use of electromagnetic waves is progressing, and pen input and non-contact charging of mobile devices using the electromagnetic induction method are popular, and magnetic shielding materials are used in combination with coil parts to prevent interference with metal parts and to effectively use magnetic fields. It is being used.

Soft magnetic metal flat powder is used for flexible magnetic sheets (resin composite sheets) used for electromagnetic noise suppression and magnetic shielding, as well as for extrusion and injection molded products. This is because the demagnetization coefficient is reduced and the magnetic permeability in the in-plane direction is increased by processing into a flat shape. In addition, it is possible to maintain permeability up to a higher frequency beyond the limit of the snake. For electromagnetic noise suppression, imaginary permeability µ'' representing magnetic loss of magnetic permeability is used, and real permeability µ' of magnetic permeability is used in magnetic shielding.

However, with the progress of thinning and miniaturization of devices in recent years, the mounting space for electromagnetic noise suppression and magnetic shielding components has become limited, and soft magnetic metal flat powder and flexible magnetic sheets (resin composite sheets) having higher permeability than before, and The demand for a resin composite composition for molding processing is increasing.

Conventionally, as soft magnetic metal flat powder using Fe-based alloy powder, it is known that the magnetic permeability of flat powder of Fe-Al-Si composition called Sendust is high. In particular, the Fe-Al-Si composition in which both the crystal magnetic anisotropy and the magnetostriction are zero is Al: 5.4wt% and Si: 9.6wt%, the remainder being Fe and unavoidable impurities. For this reason, there is Japanese Patent No. 3722391 (Patent Document 1) in which the composition is adjusted by adding surface oxidation of flat powder. On the other hand, in Japanese Patent No. 6592424 (Patent Document 2) and Japanese Unexamined Patent Publication No. 2005-281783 (Patent Document 3), it is proposed that a higher magnetic permeability can be obtained by actively adjusting the composition of Al and Si.

Patent Document 1: Japanese Patent No. 3722391 Patent Document 2: Japanese Patent No. 6592424 Patent Document 3: Japanese Unexamined Patent Publication No. 2005-281783

When communication devices or various electronic devices are actually used, there is a change in ambient temperature or heat, and there is a demand for performance guarantee at -40 to 150 ° C in automobiles and -40 to 85 ° C in others. For this reason, it is necessary to ensure stable electromagnetic noise suppression and magnetic shielding performance in a temperature range of at least -40 to 85°C. However, in general, magnetic permeability is measured only at room temperature, and Patent Documents 1, 2 and 3 do not describe obtaining a stable and high magnetic permeability in the actual operating temperature range referred to in the present invention.

Further, Patent Literature 2 describes that magnetic permeability is improved by adjusting the composition to Fe-5.4 wt% Al-9.6 wt% Si. In general, in order to increase permeability, it is effective to increase the aspect ratio to reduce the demagnetization field and to lower the coercive force, but by adjusting the composition, the coercive force increases to over 100A/m (applied magnetic field 144kA/m), , in the prior art, it has become difficult to respond to the demand for further high magnetic permeability. Further, in the Examples of Patent Literatures 2 and 3, it is not described that the total content of Al + Si and the coercive force as referred to in the present invention are satisfied. In addition, the aspect ratio has no meaning unless the size in the longitudinal direction of the powder to be measured is specified because the flatness is different for each powder to be measured, but there is no description regarding this. In addition, if only the aspect ratio is paid attention, there is a problem that the coercive force increases due to excessive grinding and the ratio of fine powder increases, but there is no description about this.

The present invention has been made to solve the above problems, and exhibits a positive temperature coefficient of magnetic permeability within the range of -40 ° C to 85 ° C, and also maintains a low coercive force, so that the soft magnetic metal flat powder and resin composite sheet has high magnetic permeability. And it is intended to provide a resin composite composition for molding processing.

The present invention solves the problems of the above-described conventional soft magnetic metal flat powder having a composition of Fe-Al-Si, a resin composite sheet using the material, and a resin composite composition for molding.

According to the present invention, the temperature coefficient K of permeability of the soft magnetic metal flat powder of Fe-Al-Si composition satisfies the following formula (1) (2) (3) in the range of -40 ° C to 85 ° C, and the coercive force is A soft magnetic metal flat powder characterized by being 70 A/m or less is obtained.

K = (μ(0°C) - μ(-40°C))/μ(-40°C) > 0 (1)

K = (μ(40°C) - μ(0°C))/μ(0°C) > 0 (2)

K = (μ(85°C) - μ(40°C))/μ(40°C) > 0 (3)

K: temperature coefficient, μ: permeability (μ': real permeability, μ": imaginary permeability)

Further, according to the present invention, the soft magnetic metal flat powder has an aspect ratio of 20 to 200 in the powder having a particle diameter around the average particle diameter D50, Al: 6 to 7.5 wt%, Si: 8.5 to 9.5 wt% %, balance: Fe and unavoidable impurities, and the total content of Al and Si is 15 to 16.5 wt%.

Further, according to the present invention, a resin composite sheet comprising the soft magnetic metal flat powder and resin and having a coercive force of 80 A/m or less can be obtained.

Further, according to the present invention, a resin composite composition for injection molding and extrusion molding characterized by comprising the soft magnetic metal flat powder and a resin is obtained.

An object of the present invention is to provide a soft magnetic metal flat powder and resin composite sheet having a high magnetic permeability and having an adjusted temperature coefficient of magnetic permeability, and a resin composite composition for molding.

1 is a graph showing the temperature dependence of the real magnetic permeability of a resin composite sheet in which 50 vol% of flat soft magnetic metal powder having a composition of Fe-5.4wt% Al-9.6wt% Si and a soft magnetic metal flat powder of different grades are blended am.
2 is a view showing the temperature dependence of real permeability in the case of a soft magnetic metal flat powder, Fe-5.4wt% Al-9.6wt% Si composition and Fe-4.5wt% Al-9.0wt% Si composition.

Hereinafter, a specific best mode of the present invention will be described.

The soft magnetic alloy raw material powder having a composition of Fe-Al-Si can be produced by various generally known methods such as a water atomization method, a gas atomization method, and an ingot pulverization method, but is not particularly limited.

It is preferable that the soft magnetic alloy raw material powder having the composition Fe-Al-Si contains 6 to 7.5 wt% of Al and 8.5 to 9.5 wt% of Si, and the total content of Al and Si is 15 to 16.5 wt%. More preferably, it is the range of 15.5 to 16 wt%. When the total content of Al and Si is less than 15 wt%, the magnetic permeability decreases because the coercive force increases, and when the total content of Al and Si exceeds 16.5 wt%, the temperature coefficient at 85 ° C. of the magnetic permeability becomes negative. Further, in addition to Fe-Al-Si, minor components such as Mn, Mo, Ca, O, and C may be added to the soft magnetic alloy raw material powder as needed.

The flattening process is not particularly limited, but can be performed in the presence of distilled water or an organic solvent using an attritor, ball mill, vibrating mill, or the like. As the organic solvent, toluene, hexane, alcohol, ethylene glycol, etc. can be used, and the atmosphere in the apparatus may be adjusted during processing. Moreover, you may add stearic acid etc. as a flattening aid. In addition, the soft magnetic alloy raw material powder may be used after performing heat treatment before flattening.

After the flattening treatment, it is preferable to heat treatment in an inert atmosphere in order to eliminate deformation of the crystals generated during processing, and the heat treatment temperature is preferably 500 to 900°C. This is because strain relief is not sufficient at 500°C or lower, and aggregation or sintering partially occurs when the temperature exceeds 900°C.

The aspect ratio of the soft magnetic metal flat powder in the vicinity of the average particle diameter D50 is preferably 20 to 200, and more preferably 30 to 150. When the aspect ratio is less than 20, the magnetic permeability decreases due to the influence of the demagnetizing field when used as a resin composite sheet and a resin composite composition for molding processing, and when it exceeds 200, workability decreases.

Moreover, it is preferable that the range of apparent density/true density is 0.036-0.086. When it becomes smaller than 0.036, flattening advances excessively and handling becomes difficult. On the other hand, since flattening is insufficient when it exceeds 0.086, magnetic permeability will fall. The apparent density was measured based on JISZ2504. The true density was measured using AccuPyc1330 manufactured by Shimadzu Corporation.

The average particle diameter D50 of the flat powder was measured using R4 by HELOS/BR-multi manufactured by Sympatec. With respect to the obtained average particle diameter D50, flat powder having a particle diameter range of ±10% was extracted by air classification, embedded in an epoxy resin, and mirror polished to obtain a sample for thickness measurement. The aspect ratio is the major axis/thickness of the flat powder, the major axis is the value of the average particle diameter D50, and the thickness of the powder flat powder is measured with a scanning electron microscope to determine the aspect ratio. The aspect ratio may be obtained by embedding a resin composite magnetic sheet or molded article in an epoxy resin and measuring the average major axis and thickness with a scanning electron microscope.

The coercive force was measured in an applied magnetic field of 148 kA/m using an automatic measuring coercometer K-HC1000 manufactured by Tohoku Tokushukou. About 10 mg of the flat powder was coated with a non-magnetic tape so as not to scatter, and was used as a sample for measurement. The coercive force measurement of the resin composite sheet and the molded product of the resin composition used a sample for measuring magnetic permeability.

The magnetic permeability was measured using an impedance analyzer E4991B manufactured by Keysight, a magnetic material test fixture 16454A, and a heat resistance test kit in a temperature range of -40°C to 85°C in a constant temperature and humidity chamber.

As the sample for measurement, one obtained by injection molding of a resin composite sheet and a resin composite composition for molding was used.

The resin composite sheet is prepared by mixing soft magnetic metal flat powder and a polymer material, making it into an ink form by various known methods, and producing a sheet-like object by doctor coating, comma coating, screen printing, etc., and further, You can also compress it with a press. Alternatively, it may be produced by kneading with a kneader or the like and roll forming, or may be further compressed by a press. Magnetic permeability can be increased by controlling the orientation of the soft magnetic metal flat powder by applying a magnetic field at the time of sheet production.

The resin composite sheet preferably has a coercive force of 80 A/m or less. More preferably, it is 70 A/m or less. It is preferable that the content of the soft magnetic metal flat powder is 35 vol% to 65 vol% with respect to the total solid content. More preferably, it is 40 vol% - 55 vol%. In the case of less than 35 vol%, the magnetic permeability becomes low even if the coercive force is 80 A/m or less, and if it exceeds 65 vol%, it becomes difficult to form a sheet and the magnetic permeability decreases.

As the polymer resin, polyurethane-based, acrylic-based, silicone-based, epoxy-based, chlorinated polyethylene-based, chloroprene-based rubber and the like can be used alone or in combination, but are not limited thereto. It is not limited also to thermoplasticity and thermosetting properties. In addition, various additives such as various surface treatments such as coupling agents, dispersants, rust inhibitors, etc., antioxidants, pigments, non-magnetic fillers, and thermally conductive fillers can be added as necessary within the range that does not impair the object of the present invention. can

The resin composite composition is obtained by mixing soft magnetic metal flat powder and polymer resin, and kneading with a kneader or a twin-screw kneader, but is not particularly limited, and can be performed by various known methods. It is preferable that the content is 35 vol% to 65 vol%. More preferably, it is 45 vol% - 55 vol%. In the case of less than 35 vol%, the magnetic permeability of the molded article is lowered, and if it exceeds 65 vol%, molding becomes difficult and the magnetic permeability decreases.

As polymer materials, thermosetting epoxy, acrylic, and urea resins, or thermoplastic polyamide, aromatic polyamide, polyphenylene sulfide, fluorine, polyether, and polyester resins can be used alone or in combination. However, it is not limited thereto. In addition, various additives such as various surface treatments such as coupling agents, dispersants, rust inhibitors, etc., antioxidants, pigments, non-magnetic fillers, and thermally conductive fillers can be added as necessary within the range that does not impair the object of the present invention. can

The resin composite composition can be molded into various shapes using an extrusion molding machine, an extrusion molding machine, or the like. During molding, you may mold while applying a magnetic field.

Example

Hereinafter, the present invention will be specifically described by examples.

The soft magnetic metal flat powder used in Examples 1 to 14 and Comparative Examples 1 to 8 was produced by an ingot pulverization method, using raw material powder having an average particle diameter D50 = 100 μm and Fe-Al-Si composition, and Flattening was performed so as to have a predetermined apparent density/true density. In Examples 1 to 14, processing conditions were adjusted so that the coercive force was 70 A/m or less. Flattening was performed under wet conditions using ethanol. After the flattening process, ethanol was removed by drying, and heat treatment for 2 hours of strain relief was performed at 800°C in an Ar atmosphere.

In Examples 1 to 12 and Comparative Examples 1 to 6, using the obtained soft magnetic metal flat powder, a thermosetting polyurethane resin was blended and dispersed in a resin solution diluted with toluene in an amount of 50 vol% based on the total solid content. This dispersion liquid was applied to a thickness of 100 μm with a comma coater, and after orientation in a magnetic field, it was dried at 50° C. to remove the solvent. The sheets after drying were stacked and hot-pressed at 150° C. under a pressure of 10 MPa to obtain a 200 μm-thick resin composite sheet for performance evaluation. Next, it was cut out into a donut shape with an outer diameter of 20 mm and an inner diameter of 10 mm, and the coercive force and magnetic permeability were measured.

Composition of the flat powders of Examples 1 to 12 and Comparative Examples 1 to 6, coercive force, average particle diameter D50, aspect ratio, apparent density/true density and coercive force in the resin composite sheet, real permeability at 0°C, 0°C Table 1 summarizes the imaginary permeability in and the temperature coefficient in each temperature range. The real permeability was 1 MHz and the imaginary permeability was 500 MHz.

In Examples 13 to 14 and Comparative Examples 7 to 8, resin composite compositions were obtained by heating and kneading the obtained soft magnetic metal flat metal and polyamide 12 using a twin-screw kneader. The soft magnetic flat powder was previously surface treated with a silane coupling agent. Next, it was molded into a ring shape having an outer diameter of 20 mm, an inner diameter of 10 mm, and a thickness of 1 mm using an injection molding machine, and the coercive force and magnetic permeability were measured.

The flat powder composition, coercive force, and aspect ratio used in the resin composite compositions of Examples 13 and 14 and Comparative Examples 7 and 8 and the amount of flat powder blended in the resin composite composition, coercive force in the molded body, real permeability at 0 ° C, real permeability at 0 ° C Tables 2 and 3 show the imaginary magnetic permeability and the temperature coefficient in each temperature range.

From Table 1, Examples 1 to 12 all have positive real and imaginary permeability temperature coefficients K at -40°C to 85°C, and higher real and imaginary permeability than Comparative Examples 1 to 5 at 0°C. In the Fe-5.4wt% Al-9.6wt% Si composition of Comparative Example 6, the real and imaginary permeability at 0 ° C are high, but when the temperature coefficient exceeds 0 ° C, it becomes negative, and the real and imaginary permeability rapidly decrease. In the Fe-5.4wt% Al-9.6wt% Si composition, as shown in Fig. 1, the higher the real permeability at 0°C, the more significant the decrease in the real permeability at 85°C.

Comparing the real permeability at 85°C, Examples 1 to 12 are all 200 or more, but the real permeability of Comparative Example 6 is 145, and there is a large difference. In addition, as shown in Fig. 2, even if the Fe-Al-Si alloy composition is adjusted outside the range of this embodiment, the temperature coefficient of real magnetic permeability can be adjusted, but the real magnetic permeability at 0 ° C is too low, and the demand for high magnetic permeability cannot be satisfied. can't

From Tables 2 and 3, even in the injection molded article of the resin composite composition, Examples 13 to 14 have positive real and imaginary permeability temperature coefficients K at -40°C to 85°C. In addition, since Fe-5.4wt% Al-9.6wt% Si of Comparative Example 7 exhibits a negative temperature coefficient when the temperature exceeds 0°C, the magnetic permeability at 85°C drops to 70. Comparative Example 8 could not be molded because the powder blending amount was too large, making it impossible to mold.

Claims (4)

Al: 6 to 7.5wt%, Si: 8.5 to 9.5wt%, balance: Fe and unavoidable impurities, the total content of Al and Si is 15 to 16.5wt%, and the coercive force is 70 A/m The soft magnetic metal flat powder below, wherein the temperature coefficient K of magnetic permeability of a resin composite sheet using the soft magnetic metal flat powder or an object molded from the resin composite composition is from the following formula (1) in the range of -40 ° C to 85 ° C (2) A soft magnetic metal flat powder which satisfies (3).
K = (μ(0°C) - μ(-40°C))/μ(-40°C) > 0 (1)
K = (μ(40°C) - μ(0°C))/μ(0°C) > 0 (2)
K = (μ(85°C) - μ(40°C))/μ(40°C) > 0 (3)
K: temperature coefficient, μ: permeability (μ': real permeability, μ'': imaginary permeability) The soft magnetic metal flat powder according to claim 1, wherein the aspect ratio of the powder in the particle diameter range of D50±10% of the average particle diameter is a flat phase of 20 to 200, the aspect ratio is the major diameter/thickness of the flat powder, and the major diameter is A soft magnetic metal flat powder characterized in that the average particle diameter D50 is the value and the thickness of the flat powder is a value measured with a scanning electron microscope. A resin composite sheet comprising the soft magnetic metal flat powder according to claim 1 or 2 and a resin, and having a coercive force of 80 A/m or less. A resin composite composition for injection molding and extrusion molding, characterized by comprising the soft magnetic metal flat powder according to claim 1 or 2 and a resin.

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