WO2019044698A1 - Dust core, method for producing said dust core, electrical/electronic component provided with said dust core, and electrical/electronic device equipped with said electrical/electronic component - Google Patents

Abstract

This dust core 1, which is provided with a molded body 1B containing a soft magnetic powder MM and an exterior coat of the molded body 1B, and wherein the exterior coat contains at least one of a thermoplastic polyimide and a thermoplastic polyamide-imide, has excellent mechanical characteristics and is not susceptible to changes in the magnetic characteristics even if used in a high temperature environment. The exterior coat may have an impregnation structure. The present invention also provides: a method for producing this dust core; an electrical/electronic component which is provided with this dust core; and an electrical/electronic device which is equipped with this electrical/electronic component.

Description

Dust core, method of manufacturing the dust core, electric / electronic component provided with the dust core, and electric / electronic device on which the electric / electronic component is mounted

The present invention relates to a dust core, a method of manufacturing the dust core, an electric / electronic component provided with the dust core, and an electric / electronic device on which the electric / electronic component is mounted.

Electrical and electronic components such as reactors, transformers, and choke coils are used in power circuits in servers of data centers, booster circuits for hybrid vehicles and the like, and electric and electronic devices such as power generation and transformation facilities. In such electric and electronic components, a dust core may be used as a magnetic member. The dust core comprises a compact obtained by compacting a large number of soft magnetic powders and heat treating the resulting shaped product.

Since the dust core is provided with the soft magnetic powder compact as described above, the dust core may be provided with an outer coat from the viewpoint of enhancing the mechanical strength. In this regard, Patent Document 1 discloses a composite magnetic material for an inductor in which a soft magnetic metal powder is bonded with a nonmagnetic material, and the nonmagnetic material is a molding aid added to and mixed with the soft magnetic metal powder. After the heat treatment of the soft magnetic metal powder / molding aid molded body, the soft magnetic metal powder / impregnated resin impregnated in the molding aid molded body as a binder is impregnated with the impregnated resin under atmospheric pressure. There is disclosed a composite magnetic material characterized in that a thermosetting temperature is 180 ° C. or higher.

Utility model registration 3145832 gazette

The use environment of the electric / electronic equipment provided with the electric / electronic parts having the above dust core is various, and the dust core is 100 ° C. because the outside air temperature is high, the dust core is located near the heat generation parts, It may be used in close environment. When used in such a high temperature environment, the material constituting the dust core may be thermally denatured. If the modification of the material changes the magnetic properties of the dust core, especially the core loss, the calorific value from the dust core may increase, which may promote the heat denaturation of the dust core. It is feared that the change in the magnetic properties of the dust core based on the use under such a high temperature environment may affect the operation stability of the electric / electronic component having the dust core. Therefore, there is a need for a dust core that is less likely to change in magnetic properties even when used under the above-described high temperature environment. There is also a need to maintain the mechanical strength of the dust core within an appropriate range when used under the above-mentioned high temperature environment.

The present invention is a dust core having less change in magnetic properties and excellent mechanical properties even when used in a high temperature environment, a method for producing the dust core, an electric / electronic component comprising the dust core, and the electricity -It aims at providing the electric and electronic equipment in which electronic parts were mounted.

One aspect of the present invention provided to solve the above problems is a dust core comprising a molded body containing a soft magnetic powder, and an outer coat of the molded body, wherein the outer coat is thermoplastic It is a dust core characterized by containing the thermoplastic resin containing at least one of a polyimide and a thermoplastic polyamide imide.

A dust core according to the present invention provided with an outer coat containing a thermoplastic resin containing at least one of a thermoplastic polyimide and a thermoplastic polyamideimide contains a conventionally used silicone resin (especially methylphenylsilicone resin). Magnetic properties, especially core loss, even when placed in a high-temperature environment (specifically, an environment of 250 ° C.) for a long time (specifically, 100 hours or longer) as compared to a dust core having an outer coating Is hard to change. Moreover, it is possible to maintain practical mechanical strength even when placed in a high temperature environment for a long time. The outer coat preferably has an impregnated structure.

In the dust core according to the present invention, the soft magnetic powder may contain at least one powder of an iron-based material and a nickel-based material.

In the dust core according to the present invention, the soft magnetic powder may contain a powder of a crystalline magnetic material. In the dust core according to the present invention, the soft magnetic powder may contain a powder of an amorphous magnetic material. In the dust core according to the present invention, the soft magnetic powder may contain a powder of a nanocrystal magnetic material. The soft magnetic powder may be a mixture of two or more selected from the crystalline magnetic material, the amorphous magnetic material, and the nanocrystal magnetic material.

In the dust core according to the present invention, the molded body comprises the soft magnetic powder and a binding component, and the binding component comprises a thermal decomposition residue of a binder component including a resin material. May be In the case where the compact provided in the dust core according to the present invention includes the above-described thermal decomposition residue, voids tend to be generated inside the compact. In general, a molded product having a large amount of voids inside tends to lack mechanical strength of the molded product. In the dust core according to the present invention, since the thermoplastic resin containing at least one of the thermoplastic polyimide and the thermoplastic polyamideimide can be positioned so as to fill the voids, the mechanical strength of the molded body is reinforced. Ru. In addition, since the outer coat is made of at least one of a highly heat resistant thermoplastic polyimide and a thermoplastic polyamide imide which is less thermally denatured, it is possible to improve the initial magnetic properties after the outer coat, and It is possible to suppress the deterioration of the magnetic properties under the high temperature environment accompanying the heat denaturation.

Another aspect of the present invention is a method for producing a dust core according to the present invention described above, which is a molded product obtained by a molding process including pressure molding of a mixture comprising the soft magnetic powder and the binder component. A forming step, a forming step obtained by the forming step is heated to obtain the forming body comprising the soft magnetic powder and a binding component comprising a thermal decomposition residue of the binder component, and a thermoplasticity, A liquid composition containing a thermoplastic resin containing at least one of a polyimide and a thermoplastic polyamideimide and a solvent is brought into contact with the molded product to form a coated film of the liquid composition in a region including the surface of the molded product, It is a manufacturing method of the dusting core characterized by providing an exterior coat process which dries a coat and volatilizes a solvent and forms an exterior coat containing the thermoplastic resin. According to the above method, it is possible to efficiently produce a dust core containing a binding component comprising thermal decomposition residue of a binder component.

Another aspect of the present invention is an electric / electronic component comprising a dust core according to the present invention, a coil, and a connection terminal connected to each end of the coil, wherein at least at least the dust core A part is an electric / electronic component characterized in being disposed so as to be located in an induced magnetic field generated by the current when a current is supplied to the coil through the connection terminal.

Another aspect of the present invention is an electric / electronic device comprising the electric / electronic component according to the above-mentioned present invention.

In the dust core according to the present invention, even when it is left for a long time (specifically, 100 hours or more) in a high temperature environment (specifically, an environment of 250 ° C.), the magnetic characteristics, particularly core loss, changes. Hateful. Moreover, it is possible to maintain practical mechanical strength even when placed in a high temperature environment for a long time. Therefore, the dust core according to the present invention is hard to change the magnetic characteristics even when used under high temperature environment, and is excellent in mechanical characteristics. Further, according to the present invention, there are provided an electric / electronic component comprising the above dust core and an electric / electronic device on which the electric / electronic component is mounted.

It is a perspective view which shows notionally the shape of the dust core which concerns on one Embodiment of this invention. (A) A schematic view of the inside of a molded product before a heat treatment step after a forming step for producing a dust core according to an embodiment of the present invention, (b) a dust core according to an embodiment of the present invention A schematic view of the inside of a molded body before an outer coating step after a heat treatment step for producing a powder, and (c) a dust core after an outer coating step for manufacturing a powder core according to an embodiment of the present invention It is a schematic diagram of the inside of. It is a figure which shows notionally the spray dryer apparatus used in one example of the method of manufacturing granulated powder, and its operation | movement. It is a perspective view which shows notionally the shape of the toroidal core which is an electronic component provided with the dust core which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
1. Dust core The dust core 1 according to the embodiment of the present invention shown in FIG. 1 has a ring-like appearance, and includes a molded body containing soft magnetic powder and an outer coat of the molded body. The dust core 1 according to an embodiment of the present invention contains a thermoplastic resin whose exterior coat contains at least one of a thermoplastic polyimide and a thermoplastic polyamideimide. As one non-limiting example, binding is performed to bind the soft magnetic powder to another material (which may be the same or different) contained in the dust core 1 Contains ingredients. The appearance of the dust core 1 is not limited to the ring shape, and there are, for example, EE type, EI type, EER type, PQ type, I type, or one in which a coil is sealed inside a dust core.

(1) Molded body (1-1) Soft magnetic powder The soft magnetic powder contained in the molded body of the dust core 1 according to one embodiment of the present invention is an iron-based material containing iron and a nickel-based material containing nickel It may contain at least one powder of

The soft magnetic powder contained in the compact of the dust core 1 according to an embodiment of the present invention may contain a powder of a crystalline magnetic material. In the present specification, "crystalline magnetic material" means a material whose structure is crystalline and which is ferromagnetic, particularly soft magnetic. The soft magnetic powder contained in the compact of the dust core 1 according to an embodiment of the present invention may be made of a powder of a crystalline magnetic material. Specific examples of crystalline magnetic materials include Fe-Si-Cr alloys, Fe-Ni alloys, Ni-Fe alloys, Fe-Co alloys, Fe-V alloys, Fe-Al alloys, Fe-Si And Fe-Si-Al alloys, carbonyl iron and pure iron.

The soft magnetic powder contained in the compact of the dust core 1 according to an embodiment of the present invention may contain a powder of an amorphous magnetic material. As used herein, "amorphous magnetic material" means a material that is a ferromagnetic material, in particular a soft magnetic material, in which the volume of the amorphous part in the tissue is more than 50% of the whole. The soft magnetic powder contained in the compact of the dust core 1 according to an embodiment of the present invention may be made of powder of an amorphous magnetic material. Specific examples of the amorphous magnetic material include Fe-Si-B alloys, Fe-PC alloys and Co-Fe-Si-B alloys. The above amorphous magnetic material may be composed of one kind of material or may be composed of plural kinds of materials. The magnetic material constituting the powder of the amorphous magnetic material is preferably one or two or more materials selected from the group consisting of the above-mentioned materials, and among these, Fe—PC based alloys are preferred. It is preferable to contain, and it is more preferable to consist of a Fe-PC type | system | group alloy.

In addition, as a specific example of the Fe- _PC based alloy of the above-mentioned amorphous magnetic material, the composition formula is represented by Fe _{100 at%-abcxy xt} Ni _a Sn _b Cr _c P _x C _y B _z Si _t , 0 at% ≦ a ≦ 10 at%
0 at% ≦ b ≦ 3 at%, 0 at% ≦ c ≦ 6 at%, 6.8 at% ≦ x ≦ 13.0 at%, 2.2 at% ≦ y ≦ 13.0 at%, 0 at% ≦ z ≦ 9.0 at% And Fe-based amorphous alloys in which 0 at% ≦ t ≦ 7 at% are included. In the above composition formula, Ni, Sn, Cr, B and Si are optional additional elements.

The addition amount a of Ni is preferably 0 at% or more and 7 at% or less, and more preferably 4 at% or more and 6.5 at% or less. The addition amount b of Sn is preferably 0 at% or more and 2 at% or less, and more preferably 0 at% or more and 1 at% or less. The addition amount c of Cr is preferably 0 at% or more and 2.5 at% or less, and more preferably 1.5 at% or more and 2.5 at% or less. In some cases, it is preferable to set the addition amount x of P to 8.8 at% or more. In some cases, it is preferable to set the addition amount y of C to 2.2 at% or more and 9.8 at% or less. The addition amount z of B is preferably 0 at% or more and 8.0 at% or less, and more preferably 0 at% or more and 2 at% or less. The addition amount t of Si is preferably 0 at% or more and 6 at% or less, and more preferably 0 at% or more and 2 at% or less.

The soft magnetic powder contained in the compact of the dust core 1 according to an embodiment of the present invention may contain a powder of a nanocrystalline magnetic material. In the present specification, "nanocrystalline magnetic material" has a nanocrystalline structure in which crystal grains having an average crystal grain size of several nm to several tens of nm are uniformly deposited in at least 50% of the structure. , A ferromagnetic material, in particular a soft magnetic material. In the nanocrystalline magnetic material, the structure other than the nanocrystalline particles may be amorphous or all may be a nanocrystalline structure. The soft magnetic powder contained in the compact of the dust core 1 according to an embodiment of the present invention may be made of a powder of a nanocrystalline magnetic material. Fe-Cu-M (here, M is one or more metal elements selected from Nb, Zr, Ti, V, Mo, Hf, Ta, W) as a specific example of the nanocrystal magnetic material-Si -B-based alloy, Fe-M-B-based alloy, Fe-Cu-M-B-based alloy, etc. may be mentioned.

The soft magnetic powder contained in the compact of the dust core 1 according to an embodiment of the present invention may be composed of one type of powder or may be a mixture of a plurality of types. Specific examples of this mixture include a mixture of two or more of a crystalline magnetic material, an amorphous magnetic material, and a nanocrystalline magnetic material. More specifically, for example, the soft magnetic powder contained in the compact of the dust core 1 according to one embodiment of the present invention is a mixture of a powder of crystalline magnetic material and a powder of amorphous magnetic material. It may be a powder of an amorphous magnetic material, and part of it may be a powder of a nanocrystalline magnetic material.

The shape of the soft magnetic powder contained in the dust core 1 according to an embodiment of the present invention is not limited. The shape of the soft magnetic powder may be spherical or non-spherical. In the case of non-spherical shape, it may be a shape having shape anisotropy such as scaly shape, elliptical spherical shape, droplet shape, needle shape, or even an irregular shape having no particular shape anisotropy. Good. As an example of the amorphous soft magnetic powder, a plurality of spherical soft magnetic powders may be bonded in contact with each other or may be bonded so as to be partially embedded in another soft magnetic powder. Such amorphous soft magnetic powder is likely to be observed when the soft magnetic powder is a powder of carbonyl iron.

The shape of the soft magnetic powder may be a shape obtained at the stage of manufacturing the soft magnetic powder, or may be a shape obtained by subjecting the manufactured soft magnetic powder to secondary processing. Examples of the shape of the former include a sphere, an oval sphere, a droplet, a needle, and the like, and examples of the shape of the latter include a scale.

The particle size of the soft magnetic powder contained in the dust core 1 according to an embodiment of the present invention is not limited. If this particle size is defined by the median diameter D50 (the particle size when the volume cumulative value in the volume distribution of the particle size of the soft magnetic powder measured by laser diffraction scattering method is 50%), it is usually 1 μm to 45 μm. It is considered a range. From the viewpoint of enhancing the handleability, and the viewpoint of enhancing the packing density of the soft magnetic powder in the compact of the dust core 1, the median diameter D50 of the soft magnetic powder is preferably 2 μm to 30 μm, and preferably 3 μm to 15 μm. It is more preferable to do, and it is especially preferable to set it as 4 micrometers or more and 13 micrometers or less.

(1-2) Binding Component The composition of the binding component is not limited as long as it is a material that contributes to fixing the soft magnetic powder contained in the dust core 1 according to an embodiment of the present invention. Organic materials such as thermal decomposition residues of resin materials and resin materials (these are generically referred to as "components based on resin materials" in the present specification), inorganic materials, etc. as materials constituting the binding component Is illustrated. Examples of the resin material include acrylic resin, silicone resin, epoxy resin, phenol resin, urea resin, and melamine resin. The binding component made of an inorganic material is exemplified by a glass-based material such as water glass. The binding component may be composed of one type of material or may be composed of a plurality of materials. The binding component may be a mixture of an organic material and an inorganic material.

Usually, an insulating material is used as the binding component. Thereby, it becomes possible to improve the insulation as the dust core 1.

The molded article of the dust core 1 according to an embodiment of the present invention is manufactured by a manufacturing method including a molding process including pressure molding of a mixture containing a soft magnetic powder and a binder component as a specific example. It is. In the present specification, the “binder component” is a component that provides a binding component, and the binder component may be a binding component or a material different from the binding component.

As a specific example in the case where the binder component is different from the binding component, the binding component included in the compact of the dust core 1 according to an embodiment of the present invention is composed of the thermal decomposition residue of the binder component containing the resin material Can be mentioned. In forming the thermal decomposition residue, a part of the binder component is decomposed and volatilized. For this reason, when the compact provided in the dust core 1 is provided with the above-described thermal decomposition residue, a void is generated in the compact, specifically, between soft magnetic powders positioned closest to each other in the compact. There is a case.

This point will be described with reference to FIG. Fig.2 (a) is a schematic diagram of the inside of the shaping | molding product before a heat treatment process after the shaping | molding process for manufacturing the powder-powder core which concerns on one Embodiment of this invention, FIG.2 (b) is a It is after the heat treatment process for producing the dust core according to one embodiment, and FIG. 2 (c) is the dust core after the outer coating process for producing the dust core according to one embodiment of the present invention. It is a schematic diagram of an inside. As shown in FIG. 2A, in the molded product 1A obtained through the molding process, the soft magnetic powder MM is bound and fixed by the binder component BM containing a resin-based material. When this molded product 1A is subjected to a heat treatment step, as shown in FIG. 2 (b), a thermal decomposition residue TDM is generated by the decomposition and volatilization of the binder component BM, and the soft magnetic powder MM of the molded body 1B is It is bound and fixed by the thermal decomposition residue TDM. For this reason, in the molded body 1B, the volume of the space PR is increased as compared with the molded product 1A.

Even in such a case, in the dust core 1 according to the present invention manufactured by performing the step including the outer coating step on the molded body 1B, as shown in FIG. A material (outer coat material) CRM that constitutes an outer coat containing a thermoplastic resin containing at least one of a thermoplastic polyimide and a thermoplastic polyamideimide can be positioned so as to fill at least a part of the void PR. Therefore, in the dust core 1, the volume of the space PR is reduced, and the soft magnetic powder MM is bound and fixed by the thermal decomposition residue TDM and the outer coating material CRM, thereby reinforcing the mechanical strength. In addition, since the exterior coating material CRM uses a thermoplastic resin containing at least one of a thermoplastic polyimide and a thermoplastic polyamideimide which does not need to be thermally cured after coating, the stress due to the thermal curing after the exterior coating is a dust core 1 Not granted. For this reason, the magnetic characteristics of the dust core 1 obtained by the exterior coating step are maintained or improved. In addition, since the exterior coating material CRM uses a thermoplastic resin containing at least one of thermoplastic polyamideimides which is less thermally denatured, the heat of the exterior coating material CRM is obtained even if the dust core 1 is placed in a high temperature environment. Deterioration of the magnetic property of dust core 1 originating in denaturation is suppressed.

(2) Exterior Coating The dust core 1 according to the embodiment of the present invention includes an exterior coating. The outer coat is a layer provided to cover at least a part of the molded body 1B for the purpose of improving the mechanical strength of the molded body 1B and the like. Since the molded body 1B is formed by press-molding a mixture containing the soft magnetic powder MM, the surface thereof may have asperities derived from the soft magnetic powder. In the case where the mixture contains the binder component BM, and the molded body 1B contains the thermal decomposition residue TDM of the binder component BM, as described above, the molded body may have the void PR. In such a case, as shown in FIG. 2 (c), the outer coating material CRM may be present not only on the surface of the molded body 1B, but also on a region which has entered the surface to a certain extent. That is, in the dust core 1 according to one embodiment of the present invention, the exterior coat preferably has an impregnated structure with respect to the molded body 1B.

The exterior coat with which the dust core 1 according to an embodiment of the present invention is provided contains a thermoplastic resin containing at least one of a thermoplastic polyimide and a thermoplastic polyamideimide. An example of a non-limiting method for producing such an outer coat is as follows. First, a liquid composition containing a thermoplastic resin (abbreviated as "thermoplastic resin" in the following description) containing at least one of a thermoplastic polyimide and a thermoplastic polyamideimide and a solvent is prepared. The concentration of the thermoplastic resin in the liquid composition is not limited, but the ease of preparation (the ease of dissolution of the thermoplastic resin), the handleability (viscosity), and the thickness of the coating formed on the molded body 1B are suitable. Considering the range, the concentration of the thermoplastic resin in the liquid composition is preferably 1% by mass or more and 40% by mass or less, and more preferably 5% by mass or more and 20% by mass or less. The type of solvent is arbitrary as long as it can dissolve the thermoplastic resin. In some cases, a mixed solvent of an aprotic polar solvent such as N-methylpyrrolidone, methyl ethyl ketone or butyl acetate and an aromatic solvent such as xylene or toluene may be preferable. The liquid composition may contain a resin or filler other than the thermoplastic resin as long as the object of the present invention can be achieved. In the following description, the case where the liquid composition contains only a thermoplastic polyimide or a thermoplastic polyamideimide as a thermoplastic resin as a solid content will be described as a specific example.

Next, the prepared liquid composition is brought into contact with the above-mentioned molded body 1B to form a coating film of the liquid composition in a region including the surface of the molded body 1B. The contact method is optional. Most simply, the molded body 1B may be immersed in the liquid composition for a predetermined time (for example, 5 minutes to 30 minutes). Alternatively, the liquid composition may be sprayed onto the molded body 1B. The atmosphere at the time of bringing the liquid composition and the molded body 1B into contact with each other may be reduced in pressure. The coating amount of the liquid composition and the thickness of the coating film formed by contact are arbitrary. As described above, since the formed body 1B has the space PR, the liquid composition can be easily impregnated into the inside of the formed body 1B by contacting in a reduced pressure atmosphere or reducing the viscosity of the liquid composition.

Subsequently, the coating film formed on the molded body 1B is dried to evaporate the solvent. The drying temperature and time are appropriately set according to the type of solvent. By way of non-limiting illustration, it is from 60 ° C. to 170 ° C. for about 20 minutes to 5 hours. It may be preferable to carry out stepwise heating.

When the dust core 1 is placed in an environment of 250 ° C., the exterior coat provided in the dust core 1 according to an embodiment of the present invention contains a thermoplastic resin and, in a preferable embodiment, is made of a thermoplastic resin. Even if it is, it is hard to produce change of a magnetic characteristic. Specifically, it is possible to make the increase rate of the core loss at 10% or less when left under the above environment for 200 hours. In addition, it is possible to set the reduction rate of the relative magnetic permeability to 6% or less (set the change rate to -6% or more) when the above-described environment is left for 200 hours.

When the dust core 1 is placed in an environment of 250 ° C., the exterior coat provided in the dust core 1 according to an embodiment of the present invention contains a thermoplastic resin and, in a preferable embodiment, is made of a thermoplastic resin. Even if it is, it is hard to produce the fall of mechanical strength. Specifically, it is possible to set the initial radial crushing strength to 15 MPa or more, and to set the radial crushing strength to 15 MPa or more even when being placed in the above environment for 200 hours.

(3) Method of Producing Powder Core Although the method of producing the powder core 1 according to the embodiment of the present invention is not particularly limited, the powder core 1 can be made more efficient if the production method described below is adopted. Manufacturing is realized.

The method for producing the dust core 1 according to an embodiment of the present invention may include a forming step and an outer coating step described below, and may further include a heat treatment step.

(3-1) Forming Step First, a mixture containing soft magnetic powder and a binder component is prepared. The formed product 1A can be obtained by the forming process including the pressure forming of the mixture. The pressure condition is not limited, and is appropriately determined based on the composition of the binder component and the like. For example, in the case where the binder component is made of a thermosetting resin, it is preferable to heat with pressure to advance the curing reaction of the resin in the mold. On the other hand, in the case of compression molding, although the pressing force is high, heating is not a necessary condition, and it becomes pressing for a short time.

Hereinafter, the case where the mixture is granulated powder and compression molding is to be described in some detail. Since the granulated powder is excellent in handleability, it is possible to improve the workability of the compression molding process, which has a short molding time and excellent productivity.

(3-1-1) Granulated Powder The granulated powder contains a soft magnetic powder and a binder component. The content of the binder component in the granulated powder is not particularly limited. When the content is excessively low, the binder component hardly holds the soft magnetic powder. Further, when the content of the binder component is excessively low, in the green compact core 1 obtained through the heat treatment step, the binding component consisting of the thermal decomposition residue of the binder component is composed of a plurality of soft magnetic powders It is difficult to insulate from On the other hand, when the content of the binder component is excessively high, the content of the binding component contained in the dust core 1 obtained through the heat treatment step tends to be high. When the content of the binding component in the dust core 1 becomes high, the magnetic properties of the dust core 1 are likely to be deteriorated due to the influence of the stress that the soft magnetic powder receives from the binding component. In addition, when the content of the binder component is excessively high, the space filling factor of the soft magnetic powder of the dust core 1 is lowered, and the magnetic properties of the dust core 1 are easily deteriorated. So, it is preferable to make content of the binder component in granulated powder into the quantity which will be 0.5 mass% or more and 5.0 mass% or less with respect to the whole granulated powder. From the viewpoint of more stably reducing the possibility of lowering the magnetic properties of the dust core 1, the content of the binder component in the granulated powder is 0.5% by mass or more with respect to the whole granulated powder. The amount is preferably 5% by mass or less, and more preferably 0.6% by mass or more and 3.0% by mass or less.

Granulated powder may contain materials other than the above-mentioned soft magnetic powder and binder component. As such a material, a lubricant, a silane coupling agent, an insulating filler and the like are exemplified. When the lubricant is contained, its type is not particularly limited. It may be an organic lubricant or an inorganic lubricant. Specific examples of organic lubricants include metal soaps such as zinc stearate and aluminum stearate. It is considered that such an organic lubricant evaporates in the heat treatment step and hardly remains in the dust core 1.

The method for producing granulated powder is not particularly limited. The ingredients to give the above-mentioned granulated powder may be mixed as it is, and the obtained kneaded product may be ground by a known method to obtain granulated powder, or the above components may be mixed with a solvent (solvent, dispersion medium, Granulated powder may be obtained by preparing a slurry formed by adding water, for example, and drying and grinding this slurry. After crushing, sieving or classification may be performed to control the particle size distribution of the granulated powder.

As an example of a method of obtaining granulated powder from said slurry, the method of using a spray dryer is mentioned. As shown in FIG. 2, a rotor 201 is provided in the spray dryer apparatus 200, and the slurry S is injected toward the rotor 201 from the top of the apparatus. The rotor 201 is rotated at a predetermined rotation speed, and the slurry S is sprayed in the form of droplets by centrifugal force in a chamber inside the spray drier apparatus 200. Furthermore, hot air is introduced into a chamber inside the spray dryer apparatus 200, whereby the dispersion medium (water) contained in the droplet slurry S is volatilized while maintaining the droplet shape. As a result, granulated powder P is formed from slurry S. The granulated powder P is recovered from the lower part of the spray drier apparatus 200.

Parameters such as the rotation speed of the rotor 201, the temperature of the hot air introduced into the spray dryer 200, the temperature of the lower portion of the chamber, etc. may be set as appropriate. Specific examples of setting ranges of these parameters include 4,000 to 6,000 rpm as the number of revolutions of the rotor 201, 130 to 170 ° C. as the temperature of hot air introduced into the spray dryer 200, and 80 to 90 ° C. as the temperature at the lower portion of the chamber. . Further, the atmosphere in the chamber and the pressure thereof may be set appropriately. As an example, the inside of the chamber is an air (air) atmosphere, and the pressure may be ₂ mm H ₂ O (about 0.02 kPa) in terms of differential pressure with respect to the atmospheric pressure. The particle size distribution of the obtained granulated powder P may be further controlled by sieving or the like.

(3-1-2) Pressure condition The pressure condition in compression molding is not particularly limited. It may be set appropriately in consideration of the composition of the granulated powder, the shape of the formed product 1A, and the like. If the pressing force during compression molding of the granulated powder is excessively low, the mechanical strength of the molded product 1A is reduced. For this reason, the handling property of the formed product 1A is reduced, and the mechanical strength of the dust core 1 obtained from the formed product 1A is easily reduced. In addition, the magnetic properties of the dust core 1 may be degraded or the insulation may be degraded. On the other hand, when the pressing force at the time of compression molding of the granulated powder is excessively high, it becomes difficult to prepare a molding die that can withstand the pressure.

From the viewpoint of more stably reducing the possibility that the compression / pressing step adversely affects the mechanical properties and magnetic properties of the dust core 1 and facilitating industrial mass production, when compacting granulated powder The pressure may be preferably 0.3 GPa or more and 2 GPa or less, or more preferably 0.5 GPa or more and 2 GPa or less, and particularly preferably 0.5 GPa or more and 1.8 GPa or less There is.

In compression molding, pressurization may be performed while heating, or pressurization may be performed at normal temperature.

(3-2) Heat Treatment Step The formed product 1A obtained in the forming step may be the formed body 1B provided in the dust core 1 according to the present embodiment, and the formed product 1A will be described next. Alternatively, a heat treatment step may be performed to obtain a molded body 1B.

In the heat treatment step, by adjusting the distance between the soft magnetic powders by heating the shaped product 1A obtained in the above shaping step, the adjustment of the magnetic properties by correcting the distance between the soft magnetic powders and the distortion imparted to the soft magnetic powders in the shaping step The magnetic characteristics are adjusted by relaxation to obtain a compact 1B.

The purpose of the heat treatment step is to adjust the magnetic properties of the compact 1B as described above, and the heat treatment conditions such as the heat treatment temperature are set so that the magnetic properties of the compact 1B become the best. As an example of the method of setting the heat treatment conditions, the heating temperature of the formed product 1A is changed, and other conditions such as the temperature rising rate and the holding time at the heating temperature are constant.

The evaluation standard of the magnetic property of the molded body 1B at the time of setting the heat treatment conditions is not particularly limited. The core loss of the molded object 1B can be mentioned as a specific example of an evaluation item. In this case, the heating temperature of the formed product 1A may be set so as to minimize the core loss of the formed body 1B. The measurement conditions of the core loss are appropriately set, and one example is a condition of a frequency of 100 kHz and a maximum magnetic flux density of 100 mT.

The atmosphere in the heat treatment is not particularly limited. In the case of an oxidizing atmosphere, the possibility of the thermal decomposition of the binder component proceeding excessively and the possibility of the oxidation of the soft magnetic powder proceeding increasing, so an inert atmosphere such as nitrogen, argon, etc., reduction of hydrogen etc. It is preferable to carry out the heat treatment in a reactive atmosphere.

(3-3) Exterior Coating Step The molded product 1B comprising the molded product 1A obtained by the above-mentioned molding step or the molded product 1B obtained by the above-mentioned heat treatment step for the molded product 1A Apply an exterior coat containing a plastic resin. Since an example of the manufacturing method is as described above, the description is omitted here.

2. Electric / Electronic Component An electric / electronic component according to an embodiment of the present invention includes the dust core according to the above-described embodiment of the present invention. Specifically, the electric / electronic component according to an embodiment of the present invention includes a dust core, a coil, and a connection terminal connected to each end of the coil. Here, at least a part of the dust core is disposed so as to be located in an induced magnetic field generated by the current when the current is supplied to the coil through the connection terminal.

The toroidal coil 10 shown by FIG. 3 is mentioned as an example of such an electrical and electronic component. The toroidal coil 10 includes a coil 2 a formed by winding the coated conductive wire 2 around the ring-shaped dust core 1. The ends 2d and 2e of the coil 2a can be defined in the portion of the conductive wire located between the coil 2a consisting of the wound coated conductive wire 2 and the ends 2b and 2c of the coated conductive wire 2. Thus, in the electric / electronic component according to the present embodiment, the member constituting the coil and the member constituting the connection terminal may be constituted by the same member. Further, the present invention is not limited to the ring-shaped dust core 1 as described above, for example, an EE-type, EI-type, EER-type, EER-type, PQ-type or I-type dust core provided with coil winding or a coil What was enclosed inside the powder core etc. are mentioned.

Since the electric / electronic component according to the embodiment of the present invention includes the dust core according to the above-described embodiment of the present invention, the electric / electronic component is long in a high temperature environment (specifically, an environment of 250 ° C.) Even when it is left for a time (specifically, 100 hours or more), deterioration of the characteristics of the electric / electronic component due to the change of the magnetic characteristics of the dust core does not easily occur. In addition, since the dust core can maintain practical mechanical strength even when it is placed in the above environment for a long time, the manufacturing process of the electric and electronic parts using the dust core, such electric and electronic parts Thermal stress due to external mechanical load such as collision with other parts or sudden temperature change during process of mounting or incorporating as a part of equipment and using the obtained electric / electronic equipment Even if a problem occurs, it is unlikely to cause a problem that the electrical and electronic parts are broken.

In addition to the above-mentioned toroidal coil 10, a reactor, a transformer, a choke coil, etc. are illustrated as electric and electronic parts concerning one embodiment of the present invention.

3. Electric / Electronic Device The electric / electronic device according to the embodiment of the present invention includes the electric / electronic component including the dust core according to the above-described embodiment of the present invention. Specifically, those on which the above-mentioned electric and electronic components are mounted and those in which the above-mentioned electric and electronic components are incorporated are exemplified. As a further specific example of such electric and electronic equipment, a switching power supply unit provided with a voltage buck-boost circuit, a smoothing circuit, a DC-DC converter, an AC-DC converter, etc., a power control unit used for solar power generation etc. Can be mentioned.

The electric / electronic component according to the embodiment of the present invention includes the electric / electronic component including the dust core according to the embodiment of the present invention, so that the high temperature environment (specifically, an environment of 250 ° C.) Even when it is left for a long time (specifically, 100 hours or more), it is hard to cause an operation failure due to the deterioration or breakage of the magnetic properties of the dust core. Therefore, the electric / electronic component according to one embodiment of the present invention is excellent in reliability.

The embodiments described above are described to facilitate the understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents that fall within the technical scope of the present invention.

Hereinafter, the present invention will be more specifically described by way of examples and the like, but the scope of the present invention is not limited to these examples and the like.

Example 1
(1) Preparation of Fe-based amorphous alloy powder Fe _{74.3 at%} Cr _{1.56 at%} P _{8.78 at%} C _{2.62 at%} B _{7.57 at%} Si _{4.19 at%} using a water atomizing method The powder of the amorphous magnetic material obtained by weighing to a composition was produced as a soft magnetic powder. The particle size distribution of the obtained soft magnetic powder was measured by volume distribution using a microtrack particle size distribution measuring apparatus ("MT3300EX" manufactured by Nikkiso Co., Ltd.). As a result, the median diameter (D50), which is the particle size at which 50% is obtained in the particle diameter distribution when the volume cumulative value in the volume distribution is 50%, is 11 μm.

(2) Preparation of Granulated Powder 98.1 parts by mass of the above soft magnetic powder, 0.8 parts by mass of an insulating binder comprising an acrylic resin, 0.6% by mass of a silane coupling agent and zinc stearate A slurry containing 0.6 parts by mass of the lubricant consisting of water as a solvent was prepared.

The obtained slurry was spray-dried with a spray dryer apparatus ("D350AT-24HOP" manufactured by Pris Co., Ltd.) to obtain granulated powder. The particle size distribution of the obtained granulated powder was measured by volume distribution using a laser diffraction scattering particle size distribution measuring apparatus ("LS 13 320" manufactured by Beckman Coulter, Inc.). As a result, the median diameter (D50) which is a particle size which will be 50% in the particle size volume distribution in case the volume accumulation value in the volume distribution of the particle size of the granulated powder measured is 85 micrometers.

(3) Compression molding The obtained granulated powder is filled in a mold and pressure molded with a surface pressure of 0.5 to 2 GPa to form a ring having an outer diameter of 20 mm, an inner diameter of 12.8 mm and a thickness of 6.8 mm. The molded product 1A which it has was obtained.

(4) Heat treatment The obtained formed product 1A is placed in a furnace in a nitrogen stream atmosphere, and the furnace temperature is 300 ° C., which is the optimum core heat treatment temperature at a heating rate of 10 ° C./min from room temperature (23 ° C.) It was heated to ̃500 ° C., held at this temperature for 1 hour, and then heat-treated to cool to room temperature in a furnace to obtain a compact 1 B.

(5) Outer coat A liquid composition in which a thermoplastic polyimide ("Q-VR-X1444" manufactured by PI Technology Inc.) is dissolved in N-methylpyrrolidone (NMP) and the concentration of the thermoplastic polyimide is 10% by mass Prepared.

The above-mentioned molded body 1B was immersed in the obtained liquid composition for 15 minutes. Thereafter, the molded product 1B is taken out of the liquid composition, dried at 80 ° C. for 30 minutes, then at 150 ° C. for 1 hour, and at 250 ° C. for 1 hour, and the coating film of the liquid composition is formed on the surface of the molded body 1B. To obtain a dust core 1 having an outer coat on the molded body 1B.

(Example 2)
In preparing the liquid composition, a thermoplastic polyamideimide ("HR-11NN" manufactured by Toyobo Co., Ltd.) is dissolved in NMP to prepare a liquid composition having a concentration of the thermoplastic polyamideimide of 10% by mass. Dust core 1 was obtained in the same manner as Example 1 except for the above.

(Example 3)
In the same manner as Example 1, a molded body 1B was obtained. A different type of thermoplastic polyamideimide ("HL-1210" manufactured by Hitachi Chemical Co., Ltd.) was dissolved in bis (2-methoxyethyl) ether to prepare a liquid composition having a concentration of thermoplastic polyamideimide of 10% by mass. Dust core 1 was obtained in the same manner as Example 1 except for the above.

(Example 4)
In the same manner as Example 1, a molded body 1B was obtained. A phenol-modified alkyd resin ("H550" manufactured by Meiden Chemical Co., Ltd.) was dissolved in xylene to prepare a liquid composition in which the concentration of the phenol-modified alkyd resin was 10% by mass. The above-mentioned molded body 1B was immersed in the obtained liquid composition for 15 minutes. Thereafter, the molded product 1B is taken out from the liquid composition, and heated at 45 ° C. for 1 hour, and then heated at 155 ° C. for 1 hour to obtain a dust core 1 having an outer coat on the molded product 1B.

(Example 5)
In the same manner as Example 1, a molded body 1B was obtained. An equivalent blend of polyamide imide ("V-8000 BM" manufactured by DIC) and bisphenol A epoxy resin ("850-S" manufactured by DIC) is diluted using cyclohexanone as a solvent, and the solid content concentration is 12% by mass A liquid composition was prepared. The above-mentioned molded body 1B was immersed in the obtained liquid composition for 15 minutes. Thereafter, the molded product 1B was taken out of the liquid composition and dried at 100 ° C. for 1 hour to form a coating film of the liquid composition on the surface of the molded product 1B. The compact 1B provided with the coating film was heated at 200 ° C. for 1 hour to obtain a dust core 1 having an outer coat on the compact 1B.

(Example 6)
When preparing a liquid composition, methyl phenyl silicone ("KR-271" manufactured by Shin-Etsu Chemical Co., Ltd.) is diluted with xylene as a solvent instead of polyamideimide and bisphenol A epoxy resin, and the concentration of methyl phenyl silicone is reduced. A dust core was obtained in the same manner as in Example 5, except that a liquid composition having a content of 20% by mass was prepared.

(Example 7)
A liquid composition having a concentration of methylphenylsilicone of 10% by mass by diluting methylphenylsilicone ("KR-300" manufactured by Shin-Etsu Chemical Co., Ltd.) different in kind using xylene as a solvent when preparing the liquid composition A dust core was obtained in the same manner as in Example 6, except that was prepared.

(Example 8)
In the same manner as Example 1, a molded body 1B was obtained. Phenyl silicone ("ASP-2010" manufactured by Shin-Etsu Chemical Co., Ltd.) was diluted with xylene to prepare a liquid composition having a solid content concentration of 20% by mass. The above-mentioned molded body 1B was immersed in the obtained liquid composition for 15 minutes. Thereafter, the molded product 1B was taken out of the liquid composition and dried at 100 ° C. for 2 hours to form a coating film of the liquid composition on the surface of the molded product 1B. The compact 1B provided with the coating film was heated at 150 ° C. for 5 hours to obtain a dust core 1 having an outer coat on the compact 1B.

(Example 9)
When preparing a liquid composition, a modified silicone ("SCR-1012" manufactured by Shin-Etsu Chemical Co., Ltd.) is diluted using xylene as a solvent to prepare a liquid composition having a concentration of methyl phenyl silicone of 10% by mass. A dust core was obtained in the same manner as in Example 8 except for the above.

(Example 10)
In the same manner as Example 1, a molded body 1B was obtained. A thermosetting polyimide ("UPIA-AT" manufactured by Ube Industries, Ltd.) was diluted with NMP to prepare a liquid composition having a solid content concentration of 10% by mass. The above-mentioned molded body 1B was immersed in the obtained liquid composition for 15 minutes. Thereafter, the molded product 1B was taken out of the liquid composition, dried at 80 ° C. for 30 minutes, and then dried at 150 ° C. for 1 hour, to form a coating film of the liquid composition on the surface of the molded product 1B. The compact 1B provided with the coating film was heated at 350 ° C. in a nitrogen atmosphere for 1 hour to obtain a dust core 1 having an outer coat on the compact 1B.

(Example 11)
When preparing a liquid composition, a liquid composition having a thermosetting polyimide concentration of 10% by mass by diluting different kinds of thermosetting polyimides ("U imide CR" manufactured by Unitika, Inc.) using NMP as a solvent Dust core 1 was obtained in the same manner as in Example 10 except that the product was prepared.

(Reference Example 1)
A dust core 1 comprising a molded body 1B obtained in the same manner as in Example 1 was obtained. That is, the dust core 1 which concerns on the reference example 1 did not have an exterior coat.

(Test Example 1) Measurement of Relative Permeability and Rate of Change The powder core 1 manufactured according to the examples and reference examples was wound with a copper wire to obtain a toroidal core. The relative permeability at a frequency of 100 kHz was measured for the toroidal core using an impedance analyzer ("4192A" manufactured by HP). This relative permeability is referred to as “initial relative permeability μ ₀ ”.
The dust core 1 produced according to the example and the comparative example was allowed to stand in an environment of 250 ° C. for 200 hours, and the relative permeability was measured in the manner described above for the dust core 1 after standing. This relative permeability is referred to as “after heating relative permeability μ ₁ ”.
The rate of change in relative permeability Rμ (unit:%) was determined by the following equation.
Rμ = (μ ₁ -μ ₀ ) / μ ₀ × 100
The initial relative permeability μ ₀ and the post-heating relative permeability μ ₁ and the change rate R μ of the relative permeability are shown in Table 1. Table 1 shows the resin species and the concentration (unit: mass%) of the liquid composition used in the examples.

Test Example 2 Measurement of Core Loss and Rate of Change Thereof A toroidal coil 10 was obtained by winding a copper wire on a dust core 1 produced according to the examples and reference examples. The core loss (PCV) of the toroidal coil 10 was measured under the conditions of a frequency of 100 kHz and a maximum magnetic flux density of 100 mT using a BH analyzer ("SY-8218" manufactured by Iwasaki Communication Co., Ltd.). This core loss is called "initial core loss W ₀ " (unit: kW / m ³ ).
The dust cores 1 produced according to the examples and comparative examples were allowed to stand in an environment of 250 ° C. for 200 hours, and core loss was measured for the dust cores 1 after standing as described above. This core loss is referred to as “after heating core loss W ₁ ” (unit: kW / m ³ ).
The core loss change rate RW (unit:%) was determined by the following equation.
RW = (W _1- W ₀ ) / W ₀ × 100
The initial core loss W ₀ and after heating core loss W ₁ and core loss change rate RW shown in Table 1.

(Test Example 3) Measurement of radial crushing strength and rate of change thereof The green compact core 1 prepared according to the examples and reference examples is measured by a test method according to JIS Z 2507: 2000, and the initial radial crushing strength S ₀ (unit: MPa Asked for).
The dust core 1 separately prepared according to the example and the comparative example is allowed to stand in an environment of 250 ° C. for 200 hours, and the dust core 1 after standing is measured by the test method according to JIS Z 2507: 2000, After heating, the radial crushing strength S ₁ (unit: MPa) was determined.
The rate of change in radial crushing strength RS (unit:%) was determined by the following equation.
RS = (S ₁ -S ₀ ) / S ₀ × 100
The initial radial crushing strength S _{0, the} post-heating radial crushing strength S _1, and the rate of change RS of the radial crushing strength are shown in Table 1.

As shown in Table 1, the dust core 1 according to the inventive example (Examples 1 to 3) has a change rate of relative permeability of − even after being placed under an environment of 250 ° C. for 200 hours. The core loss change rate was ± 10% or less, and the radial crushing strength was 15 MPa or more even after heating.
On the other hand, in the dust core 1 according to Comparative Example (Examples 4 to 11) and Reference Example (Reference Example 1), the reduction rate of relative permeability is 6% or less, and the increase rate of core loss is 10% or less And at least one of the initial radial crushing strength and the post-heating radial crushing strength could not have particularly excellent properties with respect to both the magnetic properties and the mechanical strength, for at least one of 15 MPa or more.

The electronic component using the dust core of the present invention can be suitably used as a booster circuit of a hybrid car or the like, a reactor used for power generation or transformation equipment, a transformer, a choke coil or the like.

DESCRIPTION OF SYMBOLS 1: Powdered powder core 1A: Molded product 1B: Molded body MM: Soft magnetic powder BM: Binder component TDM: Thermal decomposition residue PR: Air gap CRM: Exterior coating material 10: Toroidal coil 2: Coated conductive wire 2a: Coil 2b, 2c: End 2d of the coated conductive wire 2, 2e: End 200 of the coil 2a: Spray dryer device 201: Rotor S: Slurry P: Granulated powder

Claims (11)

1. A dust core comprising a molded body containing soft magnetic powder, and an outer coat of the molded body,
   A dust core characterized in that the outer coat contains a thermoplastic resin containing at least one of a thermoplastic polyimide and a thermoplastic polyamideimide.
2. The dust core according to claim 1, wherein the outer coat has an impregnated structure.
3. The dust core according to claim 1, wherein the soft magnetic powder contains a powder of at least one of an iron-based material and a nickel-based material.
4. The dust core according to any one of claims 1 to 3, wherein the soft magnetic powder contains a powder of a crystalline magnetic material.
5. The dust core according to any one of claims 1 to 4, wherein the soft magnetic powder contains a powder of an amorphous magnetic material.
6. The dust core according to any one of claims 1 to 5, wherein the soft magnetic powder contains a powder of nanocrystalline magnetic material.
7. The soft magnetic powder according to any one of claims 1 to 6, wherein two or more of the crystalline magnetic material, the amorphous magnetic material, and the nanocrystalline magnetic material are mixed. Dust core.
8. The said molded object is provided with the said soft-magnetic powder and a binding component, The said binding component consists of a thermal decomposition residue of the binder component containing resin-type material, The any one of Claims 1-7 Dust core as described.
9. A method of producing a dust core according to claim 8, wherein
   A forming step of obtaining a formed product by a forming process including pressure forming of a mixture comprising the soft magnetic powder and the binder component,
   A heat treatment step of heating the molded product obtained by the molding step to obtain the molded article comprising the soft magnetic powder and a binding component comprising a thermal decomposition residue of the binder component, and a thermoplastic polyimide and a thermoplastic resin A liquid composition containing a thermoplastic resin containing at least one of polyamideimide and a solvent is brought into contact with the molded product to form a coated film of the liquid composition in a region including the surface of the molded product, and the coated film is dried. A method for producing a dust core, comprising: an exterior coating step of volatilizing a solvent to form an exterior coating containing the thermoplastic resin.
10. An electric / electronic component comprising the dust core according to any one of claims 1 to 8, a coil, and a connection terminal connected to each end of the coil,
    At least a part of the dust core is disposed so as to be located in an induced magnetic field generated by the current when the current is supplied to the coil through the connection terminal. parts.
11. An electric / electronic device comprising the electric / electronic component according to claim 10.

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