阅读说明：本技术 软磁性金属扁平粉末和使用了该粉末的树脂复合片材以及成型加工用树脂复合化合物 (Soft magnetic metal flat powder, resin composite sheet using same, and resin composite compound for molding ) 是由 安井宏 日笠信彦 西山信一 行吉直也 于 2021-01-08 设计创作，主要内容包括：本发明提供具有高的磁导率且调整了磁导率的温度系数的软磁性金属扁平粉末和使用了该材料的树脂复合片材以及成型加工用树脂复合组合物。该软磁性金属扁平粉末的特征在于,Fe－Al－Si组成的软磁性金属扁平粉末的磁导率的温度系数K在－40℃～85℃的范围内满足下述式(1)(2)(3),矫顽力为70A/m以下。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：温度系数,μ：磁导率(μ’：实数磁导率,μ”：虚数磁导率)另外,提供树脂复合片材、注塑成型用和挤出成型用的树脂复合组合物,树脂复合片材的特征在于,上述软磁性金属扁平粉末由树脂构成,矫顽力为80A/m以下。(The invention provides a soft magnetic metal flat powder having high magnetic permeability and a temperature coefficient of the magnetic permeability adjusted, a resin composite sheet using the same, and a resin composite composition for molding. The flat soft magnetic metal powder is characterized in that the flat soft magnetic metal powder composed of Fe-Al-Si has a temperature coefficient K of magnetic permeability satisfying the following expressions (1), (2) and (3) in the range of-40 ℃ to 85 ℃, and has a coercive force of 70A/m or less. 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 magnetic permeability, μ: imaginary magnetic permeability) and a resin composite sheet, a resin composite composition for injection molding and extrusion molding, wherein the soft magnetic metal flat powder is made of a resin and has a coercive force of 80A/m or less.)

1. A soft magnetic metal flat powder characterized in that,

the soft magnetic metal flat powder is composed of Fe-Al-Si, the temperature coefficient K of magnetic permeability of the soft magnetic metal flat powder is in the range of-40 ℃ to 85 ℃ and satisfies the following formulas (1), (2) and (3), and the coercive force is less than 70A/m;

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 is a temperature coefficient, μ is a magnetic permeability and includes a real magnetic permeability μ' and an imaginary magnetic permeability μ ″.

2. A soft magnetic metal flat powder according to claim 1,

in the flat soft magnetic metal powder, the powder having a particle diameter/thickness ratio of 20 to 200 in the vicinity of the average particle diameter D50 is flat, and the flat soft magnetic metal powder contains, as components, Al: 6-7.5 wt%, Si: 8.5-9.5 wt%, the balance: a component consisting of Fe and unavoidable impurities, wherein the total content of Al and Si is 15 to 16.5 wt%.

3. A resin composite sheet characterized in that,

the flat soft magnetic metal powder of any one of claims 1 and 2, which contains a resin and has a coercive force of 80A/m or less.

4. A resin composite composition for injection molding and extrusion molding, characterized in that,

composed of the soft magnetic metal flat powder according to any one of claims 1 and 2 and a resin.

Technical Field

The present invention relates to a flat soft magnetic metal powder used for a noise suppression member used for preventing unwanted electromagnetic waves generated in communication equipment and various electronic equipment from leaking to the outside, interference between internal circuits, and the influence of a failure due to an external electromagnetic wave, a pen input of a mobile device using electromagnetic induction, and a magnetic shield member used in a non-contact charging module, a resin composite sheet using the same, and a resin composite composition for molding.

Background

Unnecessary electromagnetic waves are generated from communication equipment and various electronic equipment, and equipment failure and communication failure due to external and internal interference become problems, and various measures have been taken, but the problem is further remarkable in the spread of the 5G, WiFi6 communication system.

Further, as the reduction in thickness and size of communication equipment and various electronic equipment has been advanced, the mounting density of electronic components has been greatly increased, and problems due to electromagnetic interference between components and circuit boards have been frequently caused, and for this purpose, electronic components for noise countermeasure or flexible magnetic sheets (resin composite sheets) have been used.

On the other hand, effective use of electromagnetic waves has been progressing, pen input and non-contact charging of mobile devices using electromagnetic induction have been spreading, and magnetic shielding materials have been used in combination with coil components in order to prevent interference with metal components and effectively use magnetic fields.

Soft magnetic metal flat powder is used for a flexible magnetic sheet (resin composite sheet) or an extrusion or injection molded article used for suppressing electromagnetic noise and magnetic shielding. This is because the diamagnetic field coefficient is reduced and the magnetic permeability in the in-plane direction is increased by processing the magnetic material into a flat shape. In addition, exceeding the Snoek limit can maintain permeability to higher frequencies. In order to suppress electromagnetic wave noise, imaginary permeability μ ″ representing magnetic loss of permeability is used, and real permeability μ' of permeability is used in magnetic shielding.

However, due to the recent progress of reduction in thickness and size of devices, the installation space for electromagnetic noise suppression and magnetic shield members has been limited, and there has been an increasing demand for soft magnetic metal flat powder having high magnetic permeability, flexible magnetic sheet (resin composite sheet), and resin composite composition for molding.

Conventionally, flat soft magnetic metal powder using Fe-based alloy powder is known to have high permeability, and is composed of Fe — Al — Si called sendust. In particular, the Fe-Al-Si alloy with zero magnetocrystalline anisotropy and zero magnetostriction consists of Al: 5.4 wt%, Si: about 9.6 wt%, the balance being Fe and unavoidable impurities. Therefore, there is patent No. 3722391 (patent document 1) in which the composition is adjusted in consideration of the surface oxidation of the flat powder. On the other hand, patent 6592424 (patent document 2) and japanese patent laid-open publication 2005-281783 (patent document 3) propose that higher permeability can be obtained by actively adjusting the composition of Al and Si.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3722391

Patent document 2: japanese patent No. 6592424

Patent document 3: japanese patent laid-open No. 2005-281783

Disclosure of Invention

Problems to be solved by the invention

When communication equipment and various electronic equipment are actually used, the temperature of the periphery of the equipment changes or generates heat, and the requirement of performance guarantee of-40-150 ℃ in an automobile and-40-85 ℃ in other applications is met. Therefore, it is minimally necessary to ensure stable electromagnetic wave noise suppression and magnetic shielding performance in a temperature region of-40 to 85 ℃. However, the measurement of the magnetic permeability is usually performed only at normal temperature, and patent documents 1, 2 and 3 do not describe the stable achievement of high magnetic permeability in the actual use temperature range as in the present invention.

Further, patent document 2 describes that the magnetic permeability is improved by adjusting the composition from Fe-5.4 wt% Al-9.6 wt% Si. In general, it is effective to increase the aspect ratio to reduce the coercive force and increase the diamagnetic field in order to increase the permeability, but the coercive force is increased to 100A/m (applied magnetic field 144kA/m) or more by adjusting the composition, and it has been difficult to meet the demand for further increase in permeability in the prior art. In addition, in the examples of patent documents 2 and 3, there is no description about satisfying the total content of Al + Si and the coercive force in the present invention. Since the aspect ratio varies depending on the flatness processing degree for each powder to be measured, it does not mean that the dimension in the longitudinal direction of the powder to be measured is not specified, but there is no description relating to the aspect ratio. Further, if only the aspect ratio is focused, there is a problem that the powder is excessively pulverized, the proportion of fine powder increases, and the coercive force increases, but there is no description about this.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a soft magnetic metal flat powder, a resin composite sheet, and a molding resin composite composition that exhibit a positive temperature coefficient when the magnetic permeability is in the range of-40 ℃ to 85 ℃, and that have a high magnetic permeability while keeping the coercive force low.

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

Means for solving the problems

According to the present invention, there is obtained flat soft magnetic metal powder characterized in that the flat soft magnetic metal powder composed of Fe-Al-Si has a temperature coefficient K of magnetic permeability satisfying the following expressions (1), (2) and (3) in the range of-40 ℃ to 85 ℃ and a coercive force of 70A/m or less.

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 magnetic permeability, μ: imaginary magnetic permeability)

In addition, according to the present invention, there is provided flat soft magnetic metal powder, wherein the flat soft magnetic metal powder has a diameter/thickness ratio of 20 to 200 in a powder having a particle diameter of about an average particle diameter D50, and contains Al: 6-7.5 wt%, Si: 8.5-9.5 wt%, the balance: a component consisting of Fe and unavoidable impurities, wherein the total content of Al and Si is 15 to 16.5 wt%.

Further, according to the present invention, there is obtained a resin composite sheet comprising the flat soft magnetic metal powder and a resin, wherein the coercivity is 80A/m or less.

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

Effects of the invention

The invention provides a soft magnetic metal flat powder and a resin composite sheet having high magnetic permeability and a temperature coefficient of the magnetic permeability adjusted, and a resin composite composition for molding.

Drawings

FIG. 1 is a graph showing the temperature dependence of the real permeability of a resin composite sheet containing soft magnetic metal flat powder of 50 vol% Fe-5.4 wt% Al-9.6 wt% Si and soft magnetic metal flat powder of different grades of permeability.

FIG. 2 is a graph showing the temperature dependence of the real permeability in the case where the flat soft magnetic metal powder had a composition of Fe-5.4 wt% Al-9.6 wt% Si and a composition of Fe-4.5 wt% to 9.0 wt% Si.

Detailed Description

Hereinafter, a specific preferred embodiment of the present invention will be described.

The soft magnetic alloy raw material powder of Fe — Al — Si composition 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.

Preferably, the soft magnetic alloy raw material powder of Fe — Al — Si composition contains Al: 6-7.5 wt%, Si: 8.5 to 9.5 wt%, and the total content of Al and Si is 15 to 16.5 wt%. More preferably 15.5 to 16 wt%. When the total content of Al and Si is less than 15 wt%, the coercive force increases, and therefore the magnetic permeability becomes low, and when it exceeds 16.5 wt%, the temperature coefficient of the magnetic permeability at 85 ℃ becomes negative. In addition to Fe — Al — Si, the soft magnetic alloy raw material powder may contain minor components such as Mn, Mo, Ca, O, and C as needed.

The flattening is not particularly limited, and can be carried out in the presence of distilled water or an organic solvent using an attritor, a ball mill, a vibration mill, or the like. As the organic solvent, toluene, hexane, alcohol, ethylene glycol, or the like can be used, and the atmosphere in the apparatus can be adjusted during processing. Stearic acid or the like may be added as a flattening aid. Before the flattening, the soft magnetic alloy raw material powder may be used after heat treatment.

After the flattening treatment, the heat treatment is preferably performed in an inert atmosphere in order to remove the crystal strain generated during the processing, and the heat treatment temperature is preferably 500 to 900 ℃. This is because if the temperature is 500 ℃ or lower, the strain removal is insufficient, and if the temperature exceeds 900 ℃, the aggregation or sintering occurs locally.

The ratio of the diameter to the thickness of the flat soft magnetic metal powder in the powder near the average particle diameter D50 is preferably 20 to 200, and more preferably 30 to 150. If the aspect ratio is less than 20, the permeability is lowered when the resin composite sheet and the resin composite composition for molding are produced by the influence of the diamagnetic field, and the processability is lowered when the ratio exceeds 200.

The bulk density/true density is preferably in the range of 0.036 to 0.086. When the ratio is smaller than 0.036, the resulting film is too flat to be handled easily. On the other hand, when it exceeds 0.086, flattening is insufficient, and therefore, the magnetic permeability is lowered. The determination of the bulk density was carried out based on JISZ 2504. The true density was measured using AccuPyc1330 manufactured by Shimadzu corporation.

Measurement of average particle diameter D50 of the flat powder was carried out by using R4 in HELOS/BR-multi manufactured by Sympatec corporation. Flat powder having a particle size within a range of ± 10% of the obtained average particle size D50 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, but the major axis is a value of the average particle diameter D50, and the thickness of the flat powder is measured by a scanning electron microscope to determine the aspect ratio. The aspect ratio can also be determined by embedding the resin composite magnetic sheet or molded article in an epoxy resin and measuring the average major axis and thickness by a scanning electron microscope.

Coercivity was measured using an automatic measurement coercivity meter K-HC 1000 made of northeast special steel in an applied magnetic field of 148 kA/m. About 10mg of the flat powder was coated with a nonmagnetic tape so as not to scatter, thereby preparing a sample for measurement. The sample for magnetic permeability measurement was used for the coercivity measurement of the resin composite sheet and the molded article of the resin composition.

The magnetic permeability was measured in a temperature range of-40 ℃ to 85 ℃ in a constant temperature and humidity machine using an impedance analyzer E4991B manufactured by Keysight, a magnetic material test holder 16454A, and a heat resistance test unit.

The measurement sample used a resin composite sheet and an article injection-molded from the resin composite composition for molding.

The resin composite sheet may be prepared by mixing the flat soft magnetic metal powder and the polymer material, forming the mixture into an ink form by a known method, preparing a sheet-like article by doctor blade coating, comma coating, screen printing or the like, and compressing the article by a roller or a press. The resin composition may be prepared by kneading with a kneader or the like and molding with a roll, or may be further compressed by pressing. By applying a magnetic field during sheet production and controlling the orientation of the flat soft magnetic metal powder, the permeability can be increased.

The coercivity of the resin composite sheet is preferably 80A/m or less. More preferably 70A/m or less. The content of the flat soft magnetic metal powder is preferably 35 to 65 vol% based on the total solid content. More preferably 40 vol% to 55 vol%. When the coercive force is less than 35 vol%, the magnetic permeability is low even if the coercive force is 80A/m or less, and when the coercive force exceeds 65 vol%, sheeting becomes difficult and the magnetic permeability is low.

The polymer resin may be a polyurethane-based, acrylic, silicone-based, epoxy-based, chlorinated polyethylene-based, chloroprene-based rubber, or the like, alone or in combination, but is not limited thereto. The thermoplastic and thermosetting properties are not limited. In addition, various surface treatments may be performed by a coupling agent, a dispersant, a rust inhibitor, or the like as necessary, or various additives such as an antioxidant, a pigment, a nonmagnetic filler, and a thermally conductive filler may be added as necessary within a range not to impair the object of the present invention.

The resin composite composition is obtained by mixing the flat soft magnetic metal powder and the polymer resin and kneading the mixture by a kneader or a twin-shaft kneader, but the resin composite composition is not particularly limited and can be obtained by various known methods, and the content of the flat soft magnetic metal powder is preferably 35 to 65 vol% based on the total solid content. More preferably 45 vol% to 55 vol%. When the content is less than 35 vol%, the magnetic permeability of the molded product is low, and when the content exceeds 65 vol%, the molding becomes difficult and the magnetic permeability is low.

The polymer material may be a thermosetting epoxy resin, acrylic resin, urea resin, or the like, or a thermoplastic polyamide resin, aromatic polyamide resin, polyphenylene sulfide resin, fluorine resin, polyether resin, polyester resin, or the like, alone or in combination. In addition, various surface treatments may be performed by a coupling agent, a dispersant, a rust inhibitor, or the like as necessary, or various additives such as an antioxidant, a pigment, a nonmagnetic filler, and a thermally conductive filler may be added as necessary within a range not to impair the object of the present invention.

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

Examples

The present invention will be described in detail with reference to examples.

The flat soft magnetic metal powders used in examples 1 to 14 and comparative examples 1 to 8 were subjected to a flattening process using a raw material powder made of Fe — Al — Si having an average particle size D50 of 100 μm produced by an ingot grinding method so as to have a predetermined bulk density/true density by a grinder. In examples 1 to 14, the processing conditions were adjusted so that the coercive force was 70A/m or less. The flattening process was performed using ethanol and under wet conditions. After the flattening, the plate was dried to remove ethanol, and heat treatment for strain removal was performed at 800 ℃ for 2 hours in an Ar atmosphere.

The soft magnetic metal flat powder obtained in examples 1 to 12 and comparative examples 1 to 6 was mixed and dispersed in a resin solution diluted with toluene so that the content of the thermosetting polyurethane resin was 50 vol% based on the total solid content. The dispersion was applied to a thickness of 100 μm by a comma coater, oriented by a magnetic field, dried at 50 ℃ and the solvent was removed. The dried sheets were stacked and hot-pressed at 150 ℃ and 10MPa to obtain a 200 μm thick resin composite sheet for performance evaluation. Next, the steel sheet was cut out into a ring shape having an outer diameter of 20mm and an inner diameter of 10mm, and the coercive force and the magnetic permeability were measured.

The compositions, coercive force, average particle diameter D50, aspect ratio, bulk density/true density, and coercive force in the resin composite sheet, real permeability at 0 ℃, imaginary permeability at 0 ℃, and temperature coefficients at various temperature ranges of the flat powders of examples 1 to 12 and comparative examples 1 to 6 described above are collectively shown in table 1. The real permeability is a value at 1MHz, and the imaginary permeability is a value at 500 MHz.

A resin composite composition was obtained by heating and kneading the soft magnetic flat metal obtained in examples 13 to 14 and comparative examples 7 to 8 and polyamide 12 using a twin-screw kneader. Soft magnetic flat powder used was an article surface-treated with a silane coupling agent in advance. Next, the resultant was molded into a ring shape having an outer shape of 20mm, an inner diameter of 10mm and a thickness of 1mm by using an injection molding machine, and the coercive force and the magnetic permeability were measured.

The composition, coercive force, aspect ratio, and blending amount of the flat powder in the resin composite composition, coercive force in the molded body, real permeability at 0 ℃, imaginary permeability at 0 ℃, and temperature coefficient in each temperature range used in the resin composite compositions of examples 13 to 14 and comparative examples 7 to 8 described above are collectively shown in tables 2 and 3.

TABLE 1

According to Table 1, in examples 1 to 12, both of the real and imaginary magnetic permeability temperature coefficients K are positive at-40 ℃ to 85 ℃ and have real and imaginary magnetic permeability higher than those of comparative examples 1 to 5 at 0 ℃. In the Fe-5.4 wt% Al-9.6 wt% Si composition of comparative example 6, the real and imaginary permeabilities at 0 ℃ were high, but when it exceeded 0 ℃, the temperature coefficient became negative and the real and imaginary permeabilities sharply decreased. In addition, in the composition of Fe-5.4 wt% Al-9.6 wt 5% Si, as shown in FIG. 1, the higher the real permeability at 0 ℃ is, the more the reduction in the real permeability at 85 ℃ is significant.

When the real permeability at 85 ℃ is compared, examples 1 to 12 all have a real permeability of 200 or more, but comparative example 6 has a real permeability of 145, and has a large difference. Further, as shown in FIG. 2, even if the composition of the Fe-Al-Si alloy is adjusted outside the range of the present example, the temperature coefficient of the real permeability can be adjusted, but the real permeability at 0 ℃ is too low to meet the requirement of high permeability.

TABLE 2

TABLE 3

According to tables 2 and 3, in the injection-molded article of the resin composite composition, the temperature coefficient K of the real and imaginary magnetic permeability of examples 13 to 14 was positive at-40 ℃ to 85 ℃. In addition, when it exceeds 0 ℃, Fe-5.4 wt% Al-9.6 wt% Si of comparative example 7 exhibits a negative temperature coefficient, and thus the permeability at 85 ℃ is reduced to 70. Comparative example 8 was described as not moldable because the powder content was too large.