JP7211727B2 - LIQUID COMPOSITION FOR CASTING, METHOD FOR PRODUCING MOLDED PRODUCT, AND MOLDED PRODUCT - Google Patents

Description

The present invention relates to a liquid casting composition, a method for producing a molding, and a molding.

Methods for sealing elements and parts such as coils include, for example, press molding in which a powdery sealing material and a member to be sealed are pressed under high pressure; There is molding that hardens or hardens.

Patent Literature 1 describes that a composite material compact is obtained by injecting a mixed material of soft magnetic powder and resin into a mold and curing the material.

Japanese Patent Application Laid-Open No. 2008-147403

However, with the technique of Patent Document 1, sufficient fluidity could not be ensured when the content of the magnetic powder was increased. As a result, it has been difficult to obtain a compact having a high magnetic permeability.

The present invention provides a molded article having high magnetic permeability and excellent manufacturing efficiency.

According to the invention,
a powder (A) containing magnetic particles; a resin (B);
and a dispersant (C),
A liquid composition for casting is provided, wherein the content of the magnetic particles is more than 70 vol %.

Moreover, according to the present invention,
A step of introducing the member to be sealed and the liquid composition for casting into the mold;
solidifying or curing the liquid casting composition,
The liquid composition for casting is
a powder (A) containing magnetic particles; a resin (B);
and a dispersant (C),
There is provided a method for producing a molded product, wherein the content of the magnetic particles in the casting liquid composition is more than 70 vol %.

Moreover, according to the present invention,
a member to be sealed;
a sealing member that seals at least part of the member to be sealed;
The sealing member is
a powder (A) containing magnetic particles; a resin (B);
and a dispersant (C),
A molding is provided in which the content of the magnetic particles in the sealing member is more than 70 vol %.

ADVANTAGE OF THE INVENTION According to this invention, the magnetic permeability is high and the molding which is excellent in manufacturing efficiency can be provided.

It is a figure which illustrates the structure of the molding which concerns on 1st Embodiment. (a) to (c) are diagrams illustrating the structure of the member to be sealed according to the first embodiment. FIG. 3 is a diagram illustrating particle size distribution curves of powders contained in the sealing member and the composition according to the first embodiment; (a) to (e) are diagrams illustrating a method for manufacturing a molded article according to the first embodiment. (a) to (d) are diagrams illustrating a method for manufacturing a molded product according to the first embodiment. FIG. 5 is a diagram for explaining a modification of the step of introducing the member to be sealed and the composition into the mold; (a) and (b) are diagrams illustrating the structure of a molding according to a second embodiment. (a) to (c) are diagrams for explaining an example of a method for manufacturing the molding 10 according to the second embodiment. 1 is a diagram showing a particle size distribution curve of Powder 1. FIG. FIG. 2 shows a particle size distribution curve of powder 2; 3 is a diagram showing a particle size distribution curve of powder 3. FIG. 4 is a diagram showing a particle size distribution curve of powder 4. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in all the drawings, the same constituent elements are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

In addition, in the present embodiment, when the composition contains a solvent, the content in the composition refers to the content in the entire composition excluding the solvent.

(First embodiment)
FIG. 1 is a diagram illustrating the structure of a molding 10 according to the first embodiment. The molding 10 includes a member to be sealed 20 and a sealing member 30 . The sealing member 30 seals at least part of the member 20 to be sealed. Further, the sealing member 30 contains powder (A) containing magnetic particles, resin (B), and dispersant (C). The content of the magnetic particles in the sealing member 30 exceeds 70 vol %. A detailed description is given below.

FIGS. 2A to 2C are diagrams illustrating the structure of the sealed member 20 according to this embodiment. However, FIGS. 2A and 2B show a state in which a portion of the sealing member 30 is removed so that the structure of the member 20 to be sealed is easily visible. FIG. 2(c) shows a state in which the first member 31 is removed. 2(a) shows the structure viewed from the same direction as FIG. 1, and FIG. 2(b) shows the structure viewed from the left side of FIG. 2(c) shows a plan view seen from the upper side of FIG.

The member to be sealed 20 is not particularly limited, but in this embodiment, the member to be sealed 20 includes a coil. In this case, molding 10 is a molded inductor. The molding 10 can be, for example, a surface mount inductor or reactor. The coil of the member to be sealed 20 has a structure in which, for example, a conductive wire is coaxially wound multiple times. Although the type of the member to be sealed 20 is not particularly limited, it is an edgewise coil, for example. A portion of the sealing member 30 functions as a magnetic core for the coil of the member to be sealed 20 . Therefore, the higher the magnetic permeability of the sealing member 30, the higher the inductance of this inductor. The member to be sealed 20 may be entirely covered and sealed with the sealing member 30 , or may be partially sealed with the sealing member 30 . The state in which only a portion of the member to be sealed 20 is sealed with the sealing member 30 means, for example, a state in which a portion of the member to be sealed 20 is covered with the sealing member 30 and embedded in the sealing member 30 . say.

In the example shown in FIGS. 2( a ) and 2 ( b ), sealing member 30 includes first member 31 and second member 32 . The first member 31 and the second member 32 are integrally joined. The sealed member 20 includes an annular portion 201 and a wiring portion 202 . The annular portion 201 is a portion in which a conductive wire is wound multiple times about the same axis, and functions as a coil. Although the conducting wire is not particularly limited, it is, for example, a rectangular conducting wire and is covered with an insulating coating. That is, the coil includes a conductor wire at least a portion of which is coated with a coating resin material. The wiring portion 202 is electrically connected to the annular portion 201 . For example, both ends of one winding constitute the wiring portion 202, and the portion between the wiring portions 202 at both ends constitutes the annular portion 201. FIG.

The second member 32 is a plate member having a notch. The annular portion 201 is positioned above the second member 32 and covered with the first member 31 . The annular portion 201 is located between the first member 31 and the second member 32 and sealed. On the other hand, at least part of each wiring portion 202 is exposed to the outside of the sealing member 30 . The exposed portion surrounds the second member 32 . Specifically, the wiring portion 202 partially covers the surface of the second member 32 opposite to the annular portion 201 side. A part of the wiring part 202 is covered with the solder 203 after removing the insulating coating, and constitutes the terminal of the inductor. However, the structure of the molding 10 is not limited to the example shown in this figure.

In addition, as will be described later, since the molding 10 can be produced using a liquid composition, the sealing member 30 can be made thinner. As a result, the volume of the portion of the member to be sealed 20 covered with the sealing member 30 can be increased.

Next, the liquid composition according to this embodiment will be described. The molding 10 according to this embodiment can be produced using the following liquid composition.

The liquid composition according to this embodiment is a liquid composition for casting. The liquid composition contains a powder (A) containing magnetic particles, a resin (B), and a dispersant (C). Also, the content of the magnetic particles in the liquid composition exceeds 70 vol %. In addition, the preparation method of the liquid composition demonstrated below is an example. Also, the term "liquid" means that the material has fluidity to the extent that it can be injected at the temperature at which it is injected into the mold.

As mentioned above, powder (A) contains magnetic particles. Among them, the magnetic particles preferably contain soft magnetic particles. The magnetic particles are alloy particles and oxide particles containing one or more elements selected from the group consisting of Fe, Ni, Co, Cr, Si, Al, B, P, C, Mn, Zn, Cu and Nb. At least one is preferably included, and the magnetic particles more preferably include Fe (iron). Specific examples of magnetic particles include sendust and iron-based amorphous alloys. Also, the powder may contain, as particles other than the magnetic particles, one or more selected from the group consisting of silica, alumina, aluminum nitride, rubber particles and PTFE, for example. However, from the viewpoint of increasing the magnetic permeability of the sealing member 30, it is preferable that the volume content of the magnetic particles with respect to the powder is high. Each particle may be crystalline or amorphous. In addition, the particles of the powder composed of a conductive substance may be coated with an insulating coating. In this case, the dielectric strength of the liquid composition increases. On the other hand, the particles may not be coated with an insulating film.

The volume content ratio of the magnetic particles to the sealing member 30, that is, the volume content ratio of the magnetic particles to the composition is preferably more than 70 vol%, more preferably 71 vol% or more, and further preferably 72 vol% or more. preferable. By increasing the filling rate of the magnetic particles in this manner, the magnetic permeability of the magnetic core can be increased, for example, when the molding 10 is an inductor. The volume content of the magnetic particles in the sealing member 30, that is, the volume content of the magnetic particles in the composition is, for example, 95 vol% or less, preferably 85 vol% or less, more preferably 77 vol% or less. preferable.

In addition, the volume content of the powder (A) with respect to the sealing member 30, that is, the volume content of the powder (A) with respect to the composition is not particularly limited as long as it exceeds 70 vol%, but is more preferably 71 vol% or more. It is more preferably 72 vol % or more. The volume content of the powder (A) in the composition, that is, the sealing member 30 is, for example, 95 vol% or less, preferably 85 vol% or less from the viewpoint of lowering the viscosity, and preferably 77 vol% or less. more preferred.

The volume content of the powder (A) and the volume content of the magnetic particles in the sealing member 30, that is, the volume content of the powder (A) and the volume content of the magnetic particles in the solidified product or cured product of the composition can be determined according to, for example, JIS It can be measured as follows according to K 7250 (2006) "Plastics - Determination of ash content". First, the solidified or cured composition of the composition is heated to 600 ° C. in a muffle furnace to remove combustible components, the weight of the remaining powder (A) is measured, and this weight is the true density of the powder (A). The volume of the powder (A) is obtained by dividing. On the other hand, the volume of the combustible component is obtained by subtracting the weight of the powder (A) from the weight of the solidified or cured product to obtain the weight of the combustible component, and dividing this weight by the density of the combustible component. The volume content of powder (A) is expressed by {volume of powder (A)/(volume of powder (A)+volume of combustible component)}×100. Here, when the powder (A) does not contain particles other than the magnetic particles, the volume content of the powder (A) is the volume content of the magnetic particles.

When the powder (A) contains particles other than magnetic particles, the solidified or cured composition of the composition is heated to 600° C. in a muffle furnace to remove combustible components, and the remaining powder (A) is , a magnet can be used to separate magnetic particles from the rest. The volume of the magnetic particles is obtained by dividing the weight of the magnetic particles thus obtained by the true density of the magnetic particles. Also, the volume of the particles other than the magnetic particles can be obtained by dividing the weight of the particles other than the magnetic particles by the true density of the particles other than the magnetic particles. The volume content of magnetic particles is expressed by {volume of magnetic particles/(volume of magnetic particles+volume of combustible component+volume of particles other than magnetic particles)}×100.

Also, the weight content of the powder (A) in the composition, that is, the sealing member 30 is preferably 80 wt% or more, more preferably 85 wt% or more, and even more preferably 90 wt% or more. The weight content of the powder (A) in the composition, that is, the sealing member 30 is, for example, 97 wt % or less, and more preferably 95 wt % or less from the viewpoint of lowering the viscosity.

The powder (A) may contain two or more powders having different median diameters D50. By doing so, the particles are densely packed in the composition and in the sealing member 30 . According to this embodiment, even when the powder (A) in the composition has a high filling property, the composition has fluidity and a molded product can be obtained efficiently.

Here, at least one of each powder contains magnetic particles. Moreover, each powder may have a composition different from each other, or may have the same composition as each other.

The magnetic particles contained in the powder (A) are produced by, for example, an atomizing method, specifically a gas atomizing method, a water atomizing method, or a method combining the gas atomizing method and the water atomizing method. However, the magnetic particles may also be produced using other methods, such as the disk atomization method, the rotating electrode method, the carbonyl method, the chemical reduction method, or the electrolysis method. In addition, each powder contained in powder (A) may be manufactured using a mutually different method, and may be manufactured using a mutually same method.

When powder (A) contains two or more powders with different median diameters D50, two or more peaks may appear in the particle size distribution curve of powder (A).

FIG. 3 is a diagram illustrating the particle size distribution curve of the powder (A) contained in the sealing member 30 and the composition according to this embodiment. In this figure, the horizontal axis indicates the particle size, and the vertical axis indicates the frequency of particles with each particle size. A first peak 51 and a second peak 52 appear in the particle size distribution curves of the powder contained in the sealing member 30 and the composition. A second peak 52 indicates a smaller grain size than the first peak 51 .

The relationship between the first peak 51 and the second peak 52 is not particularly limited, but from the viewpoint of improving the filling property, the difference between the particle size of the first peak 51 and the particle size of the second peak 52 is 5 μm or more. It is preferably 50 μm or more, more preferably 60 μm or more. From the same point of view, the difference between the particle size of the first peak 51 and the particle size of the second peak 52 is preferably 300 μm or less, more preferably 150 μm or less, and further preferably 100 μm or less. preferable.

Here, the ratio of the powder having a particle size of ⅓ or less of the first peak to the powder (A) contained in the composition is preferably 20 vol % or more and 60 vol % or less. By doing so, particles with a relatively small diameter do not increase more than necessary, and as a result, the fluidity of the composition is less likely to decrease.

The particle size distribution of powder (A) may have three or more peaks. In that case, the first peak 51 is the largest particle size peak in the particle size distribution curve of powder (A), and the second peak 52 is the smallest particle size peak.

The height of the second peak 52 is, for example, ⅕ or more and 2 or less times the height of the first peak 51 . Between the first peak 51 and the second peak 52, there may be other peaks and multiple minimum values. The first peak 51 is, for example, preferably 30 μm or more and 300 μm or less, more preferably 50 μm or more and 150 μm or less. The second peak 52 is preferably, for example, 1 μm or more and 50 μm or less, and more preferably 3 μm or more and 30 μm or less.

D10 of the powder (A) is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 7 μm or more. On the other hand, D10 of the powder (A) is preferably 50 μm or less, more preferably 30 μm or less, even more preferably 20 μm or less. The median diameter D50 of the powder (A) is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 20 μm or more. On the other hand, the median diameter D50 of the powder (A) is preferably 300 μm or less, more preferably 200 μm or less, even more preferably 100 μm or less. The D90 of the powder (A) is preferably 10 µm or more, more preferably 50 µm or more, and even more preferably 100 µm or more. On the other hand, D90 of the powder (A) is preferably 500 μm or less, more preferably 300 μm or less, even more preferably 200 μm or less. Also, the average diameter of the powder (A) is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. On the other hand, the average diameter of the powder (A) is preferably 300 μm or less, more preferably 200 μm or less, even more preferably 100 μm or less. By setting the D10, D50, D90, and average diameter of the powder (A) within the above ranges, a low-viscosity liquid composition can be obtained using the dispersant (C).

For example, when the powder (A) contains a plurality of powders with different particle sizes, the packing properties of the particles can be enhanced. That is, it is possible to reduce the resin (B) and the like interposed between the particles. As a result, it is expected that the content of the powder (A) can be increased and the magnetic permeability of the molding 10 can be improved. On the other hand, as the filling property of the powder (A) increases, the cohesiveness in the composition also increases, making it difficult to obtain a composition having fluidity as a whole. As a result, molding becomes difficult. On the other hand, a composition that can be cast more efficiently can be obtained by selecting an appropriate component and addition amount of the dispersant (C).

The shape of the particles contained in the powder (A) is not particularly limited, and may be spherical, pulverized, or the like. From the viewpoint of improving dispersibility in the composition, the powder (A) preferably contains spherical particles. Since spherical particles have a small surface area, the amount of resin that the particles should cover in order to ensure a dispersed state is small. Therefore, even if the content of powder (A) is high, agglomeration in the composition can be avoided. It should be noted that the spherical particles do not necessarily have to be true spheres.

As the resin (B), a thermosetting resin, a moisture-curing resin, a photo-curing resin, or a thermoplastic resin can be used. Resin (B) is not particularly limited, but epoxy resin, silicone resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, diallyl phthalate resin, polyurethane resin, urethane acrylate, epoxy acrylate, ester acrylate, vinyl ether, polyolefin. , polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polystyrene, polyamide, polyacetal, polyester resin, polyphenylsulfone, polysulfone, polyethersulfone, polyarylate, cyclic polyolefin, polyetherimide, polyetheretherketone (PEEK), It preferably contains one or more resins selected from the group consisting of polyphenylene sulfide (PPS), imide resins, and fluorine resins.

Polyolefins include polyethylene, polypropylene and the like. Examples of polystyrene include acrylonitrile styrene, styrene-butadiene-acrylonitrile copolymer (ABS), and the like. Polyamides include acryl, polycarbonate, modified polyphenylene ether, 6-nylon, aromatic polyamide, aliphatic polyamide and the like. Polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and liquid crystal polymers. Examples of imide-based resins include polyamideimide, polyimide, and bismaleimide. Examples of fluororesins include polytetrafluoroethylene (PTFE) and its copolymers (PFA, ETFE, FEP, etc.), polychlorotrifluoroethylene, polyvinylidene fluoride (PVDF), and the like.

Thermosetting resins, moisture-setting resins, and photo-setting resins are preferably liquid at room temperature. From the viewpoint of improving the relative magnetic permeability, the volume content of the resin (B) in the composition is preferably 40 vol % or less, more preferably 30 vol % or less. On the other hand, from the viewpoint of improving fluidity of the composition, the volume content of the resin (B) in the composition is preferably 10 vol % or more, more preferably 15 vol % or more.

The dispersant (C) is not particularly limited, but is, for example, a polymer. Although the molecular weight of the dispersant (C) is not particularly limited, the dispersant (C) preferably contains at least one of a low-molecular-weight compound and a high-molecular-weight compound, and more preferably contains a high-molecular-weight compound. The molecular weight of the high-molecular compound is, for example, 10,000 or more, and the molecular weight of the low-molecular compound is, for example, 1,000 or less.

The dispersant (C) preferably contains, for example, a compound whose polymerization type is at least one of block copolymerization and random copolymerization, and more preferably contains a block copolymerization compound. The dispersant (C) preferably contains, for example, a compound whose molecular shape is at least one of a comb-shaped structure and a hyperbranched structure, and more preferably contains a comb-shaped compound. The dispersant (C) preferably contains a compound whose molecular structure is at least one of a polyamino structure, polyurethane structure, polyester structure, and ester structure, and more preferably contains a compound containing a polyamino structure.

From the viewpoint of low viscosity, the dispersant (C) is a group consisting of polycarboxylates, polyaminoamide salts, alkylammonium salts, alkylolammonium salts, phosphate ester salts, acrylic block copolymers, and polymer salts. It preferably contains one or more compounds selected from and more preferably contains an alkylammonium salt.

Further, the dispersant (C) may contain a compound having a pigment affinity group such as a basic group, an OH group, or the like. The dispersant (C) preferably contains a compound having an amine value of 5 mgKOH/g or more, more preferably a compound having an amine value of 30 mgKOH/g or more, and a compound having an amine value of 50 mgKOH/g or more. More preferred. The dispersant (C) preferably contains a compound having an acid value of 5 mgKOH/g or more, more preferably a compound having an acid value of 30 mgKOH/g or more, and a compound having an acid value of 50 mgKOH/g or more. is more preferred.

As the dispersant (C), specifically, BYK-Chemie: ANTI-TERRA-U100 (salt of unsaturated polyaminoamide and low-molecular-weight polyester acid, amine value 35 mgKOH/g, acid value 50 mgKOH/g), BYK-9076 (Alkyl ammonium salt of polymer copolymer, amine value 44 mgKOH/g, acid value 38 mgKOH/g), BYK-9077 (polymer copolymer having pigment affinity group, amine value 48 mgKOH/g), DISPERBYK-108 (hydroxyl group-containing carboxylic acid ester having an affinity group for pigment, amine value 71 mgKOH/g), DISPERBYK-145 (phosphoric acid ester salt of high molecular weight copolymer having pigment affinity group, amine value 71 mgKOH/g, acid value 76 mg KOH / g), DISPERBYK-2055 (copolymer having pigment affinity group, amine value 40 mg KOH / g), DISPERBYK-2152 (hyperbranched polyester), DISPERBYK-2155 (block copolymer having basic group with pigment affinity coal, amine value 48 mgKOH/g), DISPERBYK-2200 (polymeric copolymer having pigment affinity group), etc. can be used. In addition, as a dispersing agent (C), it is possible to use without being limited to the compound manufactured by BYK-Chemie.

The curing speed of the composition can also be adjusted by selecting the dispersant (C) according to the resin (B).

In order for the composition to exhibit fluidity, the particles of the powder (A) need to be covered with a certain thickness of resin on the surface. That is, in a state in which the particles are not covered with resin at all, the frictional force between the particles hinders the flow. As the content of the powder (A) is increased, the amount of resin covering the particles gradually decreases, causing an increase in friction. As a result, the viscosity of the composition increases. In addition, when the distance between the particles becomes closer, the particles may come into contact with each other (aggregation). When agglomeration occurs, the agglomerated particles may act as a single large magnetic particle, increasing the magnetic flux density. However, since the density of the magnetic particles itself is not high, magnetic saturation occurs at a low coil current, and it is presumed that the usable current range of the inductor is reduced.

By containing the dispersant (C), the composition according to the present embodiment can ensure fluidity even when the content of the powder (A) is high. By increasing the content of the magnetic particles, the magnetic permeability of the sealing member 30 can be increased. Moreover, when the molding 10 is an inductor, a wide current region can be secured as a usable region.

The content of the dispersant (C) is preferably 0.5 vol% or more, more preferably 1.0 vol% or more, and more preferably 1.5 vol% or more from the viewpoint of effectively lowering the viscosity. More preferred. In addition, the content of the dispersant (C) is preferably 10 vol% or less, more preferably 5 vol% or less, and 3 vol% or less from the viewpoint of effectively lowering the viscosity and improving the relative magnetic permeability. is more preferable.

When forming the magnetic core of an inductor using a composition containing a resin and a magnetic powder, it is necessary to increase the content of the magnetic powder in order to increase the magnetic permeability and the like of the magnetic core. On the other hand, if the content of powder is increased, the fluidity of the composition is impaired, and moldability and manufacturing efficiency are lowered.

On the other hand, since the composition according to the present embodiment contains a dispersant, it is possible to maintain high fluidity of the composition while increasing the content of powder in the composition.

The composition may further contain additives other than the powder (A), the resin (B), and the dispersant (C) as necessary. Molding agents, flame retardants, antioxidants, ion adsorbents and the like can be mentioned. Moreover, the composition may further contain a solvent as necessary. However, from the viewpoint of cost reduction, the composition according to the present embodiment preferably does not contain a coupling agent such as a silane coupling agent or a solvent.

The composition according to the present invention has a pourable viscosity at the temperature at which it is poured into the mold. For example, the composition according to the present embodiment preferably has a viscosity V _L1 of 1500 Pa·s or less at 25° C. measured 60 minutes after the start of rotation with a viscometer at a rotation speed of 0.3 rpm. Injection into the mold at room temperature is then possible. Also, from the viewpoint of improving the production efficiency and moldability of the molding 10, the viscosity V _L1 is preferably 1200 Pa·s or less, more preferably 1000 Pa·s or less. On the other hand, the viscosity _VL1 is, for example, 100 Pa·s or more.

In addition, from the viewpoint of improving production efficiency and moldability, the composition according to the present embodiment has a viscosity V _L2 of 500 Pa at 50 ° C. measured 60 minutes after the start of rotation with a viscometer at a rotation speed of 0.3 rpm. ·s or less, and more preferably 300 Pa·s or less. On the other hand, the viscosity _VL2 is, for example, 30 Pa·s or more.

In the viscosity measurement at each temperature, the temperature of the composition during rotation is kept substantially at that temperature.

In addition, the value represented by V _L1 /V _L2 of the composition according to the present embodiment is preferably 2 or more, more preferably 4 or more, and even more preferably 4.5 or more. In that case, the composition can be effectively brought into a castable state by heating. On the other hand, the value represented by V _L1 /V _L2 is, for example, 7 or less or 6 or less.

In addition, the composition according to the present embodiment preferably has a viscosity V _S1 of 3000 Pa s or less at 25° C. measured 10 minutes after the start of rotation with a viscometer at a rotation speed of 0.3 rpm, and 1500 Pa ·s or less, and more preferably 1000 Pa·s or less. On the other hand, the viscosity _VS1 is, for example, 200 Pa·s or more.

In addition, the composition according to the present embodiment preferably has a viscosity V _S2 of 400 Pa s or less at 50° C. measured 10 minutes after the start of rotation with a viscometer at a rotation speed of 0.3 rpm. ·s or less, and more preferably 200 Pa·s or less. On the other hand, the viscosity _VS2 is, for example, 40 Pa·s or more.

From the viewpoint of ensuring casting time, the value represented by V _L1 /V _S1 is preferably 0.3 or more, more preferably 0.6 or more. Also, the value represented by V _L2 /V _S2 is preferably 0.5 or more, more preferably 0.7 or more. On the other hand, from the viewpoint of shortening the curing time, the value represented by V _L1 /V _S1 is preferably 1 or less, and more preferably 0.9 or less. Also, the value represented by V _L2 /V _S2 is preferably 1.2 or less, more preferably 1 or less.

The relative magnetic permeability at 10 kHz of the solidified product or cured product of the composition according to the present embodiment can be, for example, 22 or higher, preferably 25 or higher, and more preferably over 30. Here, the relative magnetic permeability can be calculated, for example, from the inductance value of the toroidal coil. The inductance value can be measured, for example, using an LCR meter or an impedance analyzer under conditions of 500 mV and 10 kHz. The relative magnetic permeability can be controlled by adjusting the components of the composition, formulation, conditions for solidification or curing, and the like.

The relative magnetic permeability depends most strongly on the material of the powder (A), but it also depends on the state of packing and dispersion of particles, the particle size distribution, the solidified product and the state of voids in the hardened product. For example, when magnetic particles agglomerate, the agglomerated particles behave as one large magnetic particle, increasing the magnetic flux density. As a result, the magnetic flux density increases with respect to the same external magnetic field as when no aggregation occurs, and the magnetic permeability increases. On the other hand, even when the magnetic permeability is increased in this way, it is presumed that magnetic saturation occurs at a low coil current if the amount of the magnetic substance is not necessarily large.

The present composition may or may not have thixotropy. During the mixing, the mixing container may be vibrated, heated, or depressurized to defoam. By doing so, the voids contained in the resulting molding 10 can be further reduced.

FIGS. 4(a) to 4(e) and FIGS. 5(a) to 5(d) are diagrams illustrating the method for manufacturing the molding 10 according to this embodiment. This manufacturing method includes a step of introducing the member to be sealed 20 and the composition 300 into the mold 42 (hereinafter also simply referred to as “introducing step”), and a step of solidifying or curing the composition 300 . This manufacturing method can be realized using the composition 300 as described above. That is, the composition 300 is a liquid composition for casting, and contains a powder (A) containing magnetic particles, a resin (B), and a dispersant (C). The content of magnetic particles in composition 300 is more than 70 vol %. A detailed description is given below.

First, as shown in FIG. 4(a), a composition 300 degassed under reduced pressure is injected into a mold 41, and the composition 300 is solidified or hardened. Then, it is removed from the mold 41 to obtain the second member 32 as shown in FIG. 4(b). Next, as shown in FIG. 4(c), the member to be sealed 20 is placed on the second member 32. Next, as shown in FIG. At this time, the insulating coating is removed from the portion of the member to be sealed 20 that will become the terminal, and the solder 203 is coated thereon. Next, as shown in FIGS. 4(d) and 4(e), the wiring portion 202 connected to the annular portion 201 is wound around the second member 32 and fixed. FIG. 4(e) corresponds to a view of FIG. 4(d) viewed from the left.

On the other hand, as shown in FIG. 5( a ), a composition 300 degassed under reduced pressure is injected into a mold 42 . Then, as shown in FIG. 5B, the member to be sealed 20 fixed to the second member 32 is introduced into the composition 300 of the mold 42 . Then, as shown in FIG. 5(c), the composition 300 is solidified or hardened while the member 20 to be sealed is inserted into the composition 300. Then, as shown in FIG. After the sealing member 30 is solidified or hardened, the molding 10 is obtained by demolding as shown in FIG. 5(d). Note that the surface of the molding 10 may be covered with another resin.

FIG. 6 is a diagram for explaining a modification of the step of introducing the member to be sealed 20 and the composition 300 into the mold. As shown in this figure, the composition 300 may be introduced into the molding die 42 by injecting the composition 300 from an injection port 421 provided in the molding die 42 . The injection port 421 is an opening that communicates with the molding space of the mold 42 . In the process shown in this figure, the composition 300 may be injected after the member 20 to be sealed is arranged in the mold 42 .

In the steps shown in FIGS. 4 to 6, if the resin contained in the composition 300 is a thermosetting resin, for example, when the composition 300 is injected into the mold, the temperature of the mold is set below the curing temperature of the resin, After that, the temperature of the mold should be raised to the curing temperature of the resin or higher. Even if the temperature of the mold is equal to or higher than the curing temperature, depending on the temperature of the composition 300 at the time of injection, the composition 300 can spread inside the mold before the composition 300 is solidified.

If the resin contained in the composition 300 is a thermoplastic resin, for example, when the composition 300 is injected into the mold, the temperature of the mold is set to the softening temperature or higher, and then the mold temperature is set to the softening temperature or lower. Note that even if the temperature of the mold is lower than the softening point, depending on the temperature of the composition 300 at the time of injection, the composition 300 can spread inside the mold before the composition 300 solidifies.

In the method, composition 300 includes a dispersant, as described above. Therefore, the composition 300 has sufficient fluidity for casting. Therefore, in the step of injecting (introducing) the composition 300 into the mold 42, the atmosphere may be 7000 hPa or less, such as normal pressure, high pressure, or reduced pressure. For example, the composition 300 can be poured into the mold 42 under normal pressure. Specifically, the composition 300 can be poured only by gravity into the mold 42 under atmospheric pressure in which the upper part of the molding space is open. Moreover, even when the composition 300 is injected from the injection port 421, there is no need to press the composition 300 into the molding space at high pressure or draw the composition 300 into the molding space by depressurizing the molding space. However, there is no problem even if the inside of the molding space is depressurized or the composition 300 is forced into the molding space by applying pressure in order to improve manufacturing efficiency or the like.

In addition, in this method, the composition 300 may be heated if it is necessary to further increase the fluidity of the composition 300 in the step of injecting (introducing) the composition 300 into the mold 42 . However, if the composition 300 has high fluidity even without being heated, the composition 300 may not be heated.

In addition, in this method, after the step of introducing the composition 300 into the mold 42, before the step of solidifying or curing the composition 300, the composition 300 and the member to be sealed 20 are introduced into the mold 42. Vibration may be applied, heating may be performed, or degassing may be performed by reducing the pressure. By doing so, the voids contained in the obtained molding 10 can be further reduced.

When sealing a coil or the like by performing press molding accompanied by a high-pressure press in the manufacture of a molded article, the pressure balance between the upper and lower sides may be lost and cracks may occur. Also, distortion during molding may cause deterioration in electromagnetic properties. On the other hand, according to this method, the molding 10 can be manufactured by molding without high-pressure pressing instead of press molding. Therefore, it is possible to suppress the occurrence of cracks and deterioration of properties. In addition, no equipment for pressing is required. Furthermore, since there is no need to consider pressure resistance, there are few restrictions on the shape of the member to be sealed and the molded product.

Moreover, since the composition 300 according to the present embodiment has fluidity, it can enter even narrow gaps in the molding space of the molding die 42 . Therefore, the sealing member 30 can be made thin. For example, the minimum thickness of the sealing member 30 between the surface of the member to be sealed 20 and the surface of the sealing member 30 is, for example, 0.5 mm.

In the case of press molding, there are almost no voids in the sealing member, whereas in the sealing member 30 of the molded product 10 obtained by molding like the method according to the present embodiment, There are voids to the extent that there is no problem with the quality of the molding 10 . In addition, when the molded product 10 is an inductor, the molded product 10 obtained by molding such as the present method has less crystal strain and lower iron loss than a molded product obtained by press molding. Also, the self-resonant frequency of the molding 10 can be set to, for example, 1000 kHz or higher.

When the powder (A) is highly filled with few voids, the density of the sealing member 30 increases. As a result, the relative magnetic permeability of the sealing member 30 can be increased. Although the density of the sealing member 30 is not particularly limited, it is preferably 3 g/cm ³ or more, more preferably 5 g/cm ³ or more, and even more preferably 5.4 g/cm ³ or more. On the other hand, the density of sealing member 30 is, for example, 7 g/cm ³ or less. The density of the sealing member 30 can be measured, for example, by the Archimedes method.

Next, the operation and effects of this embodiment will be described. According to this embodiment, the composition and sealing member comprise a dispersant (C). Therefore, the fluidity of the composition can be ensured while increasing the filling rate of the powder. Therefore, the powder content of the sealing member 30 can be increased. In addition, since the sealing member 30 can be molded, the manufacturing efficiency of moldings such as the sealing member 30 is high.

(Second embodiment)
FIGS. 7(a) and 7(b) are diagrams illustrating the structure of the molding 10 according to the second embodiment. FIG. 7(b) shows a state in which part of the sealing member 30 is removed from the molding 10 shown in FIG. 7(a). The method for manufacturing the molded product 10 according to this embodiment is the same as the method for manufacturing the molded product 10 according to the first embodiment except for the points described below.

In this embodiment, the member to be sealed 20 includes a coil 21 and a pedestal 22 . Coil 21 includes an annular portion 211 and a wiring portion 212 . The configurations of the annular portion 211 and the wiring portion 212 are the same as the configurations of the annular portion 201 and the wiring portion 202 described in the first embodiment, respectively. The pedestal 22 is a member molded using resin. However, the pedestal 22 may be manufactured using other materials. The pedestal 22 includes a bottom plate portion 222 and a support portion 221 having one end fixed to the bottom plate portion 222 . The support portion 221 is positioned between the bottom plate portion 222 and the annular portion 211 . In the member to be sealed 20 before being sealed with the sealing member 30 , the supporting portion 221 supports the annular portion 211 at the other end. At least parts of the wiring portions 212 on both sides of the annular portion 211 are exposed to the outside of the sealing member 30 . The exposed portion surrounds the bottom plate portion 222 . Specifically, the wiring portion 212 partially covers the surface of the bottom plate portion 222 opposite to the annular portion 211 side. A part of the wiring part 212 is covered with the solder 213 after removing the insulating coating, and constitutes the terminal of the inductor.

FIGS. 8(a) to 8(c) are diagrams for explaining an example of the method for manufacturing the molding 10 according to this embodiment. In this method, as shown in FIG. 8A, first, the coil 21 is fixed to the pedestal 22 to obtain the member 20 to be sealed. Note that FIG. 8(a) corresponds to FIG. 4(d) of the first embodiment. Next, the composition 300 degassed under reduced pressure and the member 20 to be sealed are introduced into the mold 42 as shown in FIG. 8(b). Then, after the composition 300 is solidified or hardened in the state shown in FIG. In this manufacturing method, after the step of introducing the composition 300 into the mold 42, the conditions of the step of solidifying or curing the composition 300 are the same as those described in the first embodiment.

The molding 10 according to the present embodiment can be manufactured without separately using the second member 32 made of the solidified or hardened material of the composition 300 as in the first embodiment. Moreover, since the pedestal 22 is a resin member, the molded product 10 can be made lightweight and inexpensive.

This embodiment also provides the same actions and effects as those of the first embodiment.

Hereinafter, this embodiment will be described in detail with reference to examples. It should be noted that the present embodiment is not limited to the description of these examples.

[Examples 1 to 12, Comparative Examples]
<Preparation of composition>
Compositions according to Examples 1 to 12 and compositions according to Comparative Examples were prepared according to the formulations shown in Tables 1 and 2. Table 3 shows the "type of powder (A)" in Tables 1 and 2. In Table 3, "filler species" are shown in Table 4.

In Table 4, "amorphous" is an alloy of Fe-6.8%Si-2.6%B-2.5%Cr-0.8%C (iron-based amorphous alloy) and was amorphous. . "Sendust" was an alloy of Fe-9.5% Si-5.5% Al and was crystalline. A phosphate film was used as the insulating coat.

The resin (B) and dispersant (C) used in the compositions of Examples 1 to 12 and Comparative Examples are as follows.
Resin 1: Bisphenol A epoxy resin containing a curing agent (acid anhydride) Dispersant 1: DISPERBYK-145 manufactured by BYK Chemie

In the preparation of each composition according to Examples 1 to 12 and Comparative Examples, first, as shown in Table 3, two types of fillers were mixed to obtain powders. Next, the powder, resin, and dispersant were combined according to the formulations shown in Tables 1 and 2 and mixed in an automatic mortar for 5 minutes to obtain a composition. Each composition was degassed under reduced pressure at 4 kPa for 30 minutes and used for the following measurements and inductor production.

<Production of inductor>
An inductor as shown in FIG. 1 was produced using the composition according to each example. Among Examples 1 to 12, the compositions according to Examples other than Examples 4 and 10 had fluidity at room temperature (25°C) and could be poured into a mold at normal pressure. . In producing inductors, each composition was cured at 130° C. for 3 hours after casting.

The compositions of Examples 4 and 10 were not flowable at room temperature, but were flowable at 50°C. Therefore, the composition was heated to 50° C. and poured into a mold under normal pressure. After casting, each composition was cured at 130° C. for 3 hours.

Comparing Example 4 using Powder 1 and Example 5 using Powder 2, it can be said that the fluidity of the composition in Example 5 is superior to that in Example 4, based on the presence or absence of fluidity at room temperature. .

Comparative compositions did not contain a dispersant. As a result, it was not possible to obtain sufficient fluidity even at room temperature or at heating to 50° C., and it was not possible to produce an inductor having sufficient quality as a product by molding.

<Particle size distribution>
The particle size distribution was measured for powders 1-4. The measurement was performed using a laser diffraction/scattering particle size distribution analyzer (LA-950V2, manufactured by Horiba, Ltd.). Particle size distribution curves for powders 1-4 are shown in FIGS. 9-12, respectively.

The particle size distribution curve for each particle showed a peak corresponding to the particle size of each filler type. Of the two peaks of each powder, the peak with the larger particle size is the first peak, and the peak with the smaller particle size is the second peak. The difference between the particle diameters of the two peaks was 60 μm or more and 100 μm or less. Table 3 summarizes the particle size of the first peak, the particle size of the second peak, and the peak ratio (peak value of the second peak/peak value of the first peak). Further, in powders 2 to 4, the peak value of the first peak was larger than the peak value of the second peak. The reason why the peak value of the first peak is smaller than the peak value of the second peak in the powder 1 is considered to be that the peak of the particle size distribution of the filler A is broad.

Table 5 shows the D10, D50, D90 and average diameter of each powder.

<Viscosity of composition>
The viscosity of each composition according to Examples 1-3, 5-9, 11 and 12 was measured. The measurement was performed using a digital B-type viscometer (BASE PLUS L manufactured by Atago Co., Ltd.) at a rotation speed of 0.3 rpm. Measurement temperatures were 25°C and 50°C. Further, the viscosity was read 10 minutes after the rotation of the viscometer and 60 minutes after the start of rotation of the viscometer at each temperature. Viscosity V _S1 at 25° C. measured 10 minutes after starting rotation, Viscosity V _L1 at 25° C. measured 60 minutes after starting rotation, Viscosity V _S2 at 50° C. measured 10 minutes after starting rotation , viscosities V _L2 and V _L1 /V _L2 values, V _L1 /V _S1 values, and V _L2 /V _S2 values at 50° C. measured 60 minutes after the start of rotation are shown in Tables 6 and 7. show.

The viscosity measured with a viscometer mainly tended to decrease as time passed from the start of rotation, and was almost stable 60 minutes after the start of rotation. It was also confirmed that there is a correlation between the viscosity measured 10 minutes after the start of rotation and the viscosity measured 60 minutes after the start of rotation. Specifically, there was a tendency that the higher the viscosity measured after 10 minutes, the higher the viscosity measured after 60 minutes.

<Relative magnetic permeability of cured product>
The relative magnetic permeability of the cured product of the composition according to each example was measured. Specifically, the inductance value of the inductor produced as described above was measured for each composition, and the relative magnetic permeability was calculated from the obtained inductance value. The inductance value was measured using an impedance analyzer (4294A manufactured by Agilent Technologies) under conditions of 500 mV and 10 kHz. The results are shown in Tables 8 and 9.

<Moldability evaluation>
Each composition of Examples 1 to 12 was evaluated for moldability. Specifically, a part of the cured product of the composition was cut out from the inductor manufactured as described above using each composition and used as a measurement sample. Then, the moldability of the obtained measurement samples was evaluated as follows. First, the calculated value d1 of the density of the composition was calculated based on the components and formulation of the composition. On the other hand, the measured value d2 of the density of the measurement sample was measured by the Archimedes method. A value of d2/d1 was calculated from the obtained d1 and d2. The results are also shown in Tables 8 and 9.

Since the measured value d2 becomes smaller than the calculated value d1 when voids and air bubbles are present inside the cured product, it can be said that the larger the value of d2/d1, the fewer the internal voids and air bubbles. It can be evaluated that there is.

Comparing the results of Examples 1 to 4 in which the content of each component was changed, the compositions of Examples 1 to 3 were superior to the composition of Example 4 in moldability. In addition, when comparing the results of Examples 7 to 10 in which the content of each component was changed, the compositions of Examples 7 to 9 had better moldability than the composition of Example 10. .

Comparing Example 4 using Powder 1 and Example 5 using Powder 2, Example 5 was superior to Example 4 in moldability of the composition. Further, when Example 10 using powder 3 and Example 11 using powder 4 were compared, the moldability of the composition in Example 11 was superior to that in Example 10.

The relationship between formability and relative magnetic permeability is discussed below. Among the above examples, Examples 1 to 4 differ from each other in the content of the magnetic particles. In Examples 1 to 3, the relative magnetic permeability increases as the actual density value d2 increases. On the other hand, in Example 4, although the measured value d2 is small, the relative permeability is improved. Aggregation of magnetic particles is considered to be one cause of this, and it is speculated that magnetic saturation occurs at a low coil current. Therefore, as in Examples 1 to 3, it is more preferable to realize a high measured value d2 by improving moldability, and as a result, improve the relative magnetic permeability. Examples 1-3 appear to have particularly good dispersion of the individual magnetic particles in the composition.

[Examples 13 to 26]
<Preparation of composition>
Compositions according to Examples 13 to 26 were prepared in the same manner as in Example 1. The formulation of each composition is as shown in Table 10, and the dispersant (C) used is as shown in Table 11. All the dispersants (C) shown in Table 11 are manufactured by BYK-Chemie. In Table 10, "Powder 1" and "Resin 1" are as described above for Example 1 and the like. In addition, Table 12 summarizes the details of each dispersant.

<Production of inductor>
An inductor as shown in FIG. 1 was produced using the composition according to each example. The compositions of Examples 13 to 26 had fluidity at room temperature (25° C.) and could be cast into molds under normal pressure. In producing inductors, each composition was cured at 130° C. for 3 hours after casting.

<Viscosity of composition>
The viscosities of the compositions of Examples 13 to 26 were measured. Measurement was performed using a digital B-type viscometer (BASE PLUS L manufactured by Atago Co., Ltd.) under the following conditions. In addition, the viscosity after 10 minutes from the start of rotation for measurement was read as a measured value. The results are summarized in Table 11. The viscosity measured under condition 1 corresponds to viscosity _VS1 , and the viscosity measured under condition 2 corresponds to viscosity _VS2 .
Condition 1: measurement temperature 25°C, number of revolutions 0.3 rpm
Condition 2: measurement temperature 50°C, rotation speed 0.3 rpm
Condition 3: measurement temperature 50°C, number of revolutions 3 rpm

In particular, the viscosity of the composition was low in Examples using DISPERBYK-145 and Examples using BYK-9076 as the dispersant (C). In particular, in Example 24, a low viscosity was achieved with a small amount of dispersant, which is particularly effective in obtaining an inductor with high magnetic permeability by molding. The difference in the measurement results between Example 1 and Example 21 is considered to be due to variations. The measured values after 60 minutes from the start of rotation have relatively small variations.

Although the embodiments of the present invention have been described above with reference to the drawings, these are examples of the present invention, and various configurations other than those described above can also be adopted.
Examples of reference forms are added below.
1. a powder (A) containing magnetic particles;
a resin (B);
and a dispersant (C),
A liquid composition for casting, wherein the content of the magnetic particles is more than 70 vol %.
2. 1. In the casting liquid composition according to
A casting liquid composition having a viscosity of 100 Pa·s or more and 1500 Pa·s or less at 25°C, measured with a viscometer at a rotation speed of 0.3 rpm 60 minutes after the start of rotation.
3. 1. or 2. In the casting liquid composition according to
A casting liquid composition having a viscosity of 30 Pa·s or more and 500 Pa·s or less at 50°C measured 60 minutes after the start of rotation with a viscometer at a rotation speed of 0.3 rpm.
4. 1. to 3. In the casting liquid composition according to any one of
When the viscosity at 25° C. is V _L1 and the viscosity at 50° C. is V _L2 , measured 60 minutes after the start of rotation at a rotation speed of 0.3 rpm with a viscometer, it is expressed as V _L1 /V _L2 . A liquid composition for casting whose value is 2 or more and 7 or less.
5. 1. to 4. In the casting liquid composition according to any one of
The powder (A) has a D10 of 1 μm or more and 50 μm or less, a median diameter D50 of 5 μm or more and 300 μm or less, and a D90 of 10 μm or more and 500 μm or less.
6. 1. to 5. In the casting liquid composition according to any one of
A liquid composition for casting, wherein the relative magnetic permeability of the solidified or cured product of the liquid composition for casting is 22 or more at 10 kHz.
7. 1. to 6. In the casting liquid composition according to any one of
The dispersant (C) is a casting liquid composition containing a polymer compound.
8. 7. In the casting liquid composition according to
The dispersant (C) is one or A liquid casting composition comprising two or more compounds.
9. 1. to 8. In the casting liquid composition according to any one of
A liquid composition for casting, wherein the content of the dispersant (C) is 0.5 vol % or more and 10 vol % or less.
10. 1. to 9. In the casting liquid composition according to any one of
The resin (B) includes epoxy resin, silicone resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, diallyl phthalate resin, polyurethane resin, urethane acrylate, epoxy acrylate, ester acrylate, vinyl ether, polyolefin, and polyvinyl chloride. , polyvinylidene chloride, polyvinyl acetate, polystyrene, polyamide, polyacetal, polyester resin, polyphenylsulfone, polysulfone, polyethersulfone, polyarylate, cyclic polyolefin, polyetherimide, polyetheretherketone (PEEK), polyphenylene sulfide (PPS) ), imide-based resins, and fluororesins.
11. 1. to 10. In the casting liquid composition according to any one of
The liquid composition for casting, wherein the magnetic particles include soft magnetic particles.
12. 1. to 11. In the casting liquid composition according to any one of
The liquid composition for casting, wherein the magnetic particles contain iron.
13. A step of introducing the member to be sealed and the liquid composition for casting into the mold;
solidifying or curing the liquid casting composition,
The liquid composition for casting is
a powder (A) containing magnetic particles;
a resin (B);
and a dispersant (C),
A method for producing a molded product, wherein the content of the magnetic particles in the casting liquid composition is more than 70 vol %.
14. 13. In the method for producing a molded article according to
A method for producing a molded product, wherein in the introducing step, the casting liquid composition is poured into the mold at a pressure of 7000 hPa or less.
15. 14. In the method for producing a molded article according to
A method for producing a molded product, wherein in the introducing step, the casting liquid composition is poured into the mold under normal pressure.
16. 13. to 15. In the method for producing a molded product according to any one of
The member to be sealed is a method for manufacturing a molded article including a coil.
17. a member to be sealed;
a sealing member that seals at least part of the member to be sealed;
The sealing member is
a powder (A) containing magnetic particles;
a resin (B);
and a dispersant (C),
A molding, wherein the content of the magnetic particles in the sealing member exceeds 70 vol %.
18. 17. In the molding described in
The member to be sealed is a molding including a coil.
19. 18. In the molding described in
The coil is a molding including a conductive wire at least partially covered with a covering resin material.
20. 17. to 19. In the molded article according to any one of
The molding, wherein the sealing member has a density of 3 g/cm ³ or more and 7 g/cm ³ or less.

10 Molded product 20 Sealed member 21 Coil 22 Base 30 Sealing member 31 First member 32 Second member 41 Mold 42 Mold 51 First peak 52 Second peak 201 Annular portion 202 Wiring portion 203 Solder 211 Annular portion 212 Wiring portion 213 Solder 221 Support portion 222 Bottom plate portion 300 Composition 421 Injection port

Claims (21)

a powder (A) containing magnetic particles; a resin (B);
and a dispersant (C),
The content of the magnetic particles exceeds 70 vol% ,
The dispersant (C) contains a polymer compound,
The dispersant (C) is one or comprising two or more compounds,
A liquid composition for casting , wherein the content of the dispersant (C) is 0.5 vol % or more and 10 vol % or less . a powder (A) containing magnetic particles;
a resin (B);
and a dispersant (C),
Contains no solvents,
The content of the magnetic particles exceeds 70 vol%,
The content of the dispersant (C) is 0.5 vol% or more,
The dispersant (C) is a casting liquid composition containing a compound containing at least one of a polyamino structure, a polyurethane structure, a polyester structure and an ester structure. In the liquid casting composition according to claim 2,
A liquid composition for casting, wherein the content of the dispersant (C) is 10 vol % or less. In the liquid composition for casting according to claim 2 or 3,
The dispersant (C) is a casting liquid composition containing a polymer compound. In the liquid casting composition according to any one of claims 1 to 4 ,
A casting liquid composition having a viscosity of 100 Pa·s or more and 1500 Pa·s or less at 25°C, measured with a viscometer at a rotation speed of 0.3 rpm 60 minutes after the start of rotation. In the liquid casting composition according to any one of claims 1 to 5 ,
A casting liquid composition having a viscosity of 30 Pa·s or more and 500 Pa·s or less at 50°C measured 60 minutes after the start of rotation with a viscometer at a rotation speed of 0.3 rpm. In the liquid casting composition according to any one of claims 1 to 6 ,
When the viscosity at 25° C. is V _L1 and the viscosity at 50° C. is V _L2 , measured 60 minutes after the start of rotation at a rotation speed of 0.3 rpm with a viscometer, it is expressed as V _L1 /V _L2 . A liquid composition for casting whose value is 2 or more and 7 or less. In the liquid casting composition according to any one of claims 1 to 7 ,
The powder (A) has a D10 of 1 μm or more and 50 μm or less, a median diameter D50 of 5 μm or more and 300 μm or less, and a D90 of 10 μm or more and 500 μm or less. In the liquid casting composition according to any one of claims 1 to 8 ,
A liquid composition for casting, wherein the relative magnetic permeability of the solidified or cured product of the liquid composition for casting is 22 or more at 10 kHz. In the liquid casting composition according to any one of claims 1 to 9,
The resin (B) includes epoxy resin, silicone resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, diallyl phthalate resin, polyurethane resin, urethane acrylate, epoxy acrylate, ester acrylate, vinyl ether, polyolefin, and polyvinyl chloride. , polyvinylidene chloride, polyvinyl acetate, polystyrene, polyamide, polyacetal, polyester resin, polyphenylsulfone, polysulfone, polyethersulfone, polyarylate, cyclic polyolefin, polyetherimide, polyetheretherketone (PEEK), polyphenylene sulfide (PPS) ), imide-based resins, and fluororesins. In the liquid casting composition according to any one of claims 1 to 10,
The liquid composition for casting, wherein the magnetic particles include soft magnetic particles. In the liquid casting composition according to any one of claims 1 to 11,
The liquid composition for casting, wherein the magnetic particles contain iron. A step of introducing the member to be sealed and the liquid composition for casting into the mold;
solidifying or curing the liquid casting composition,
The liquid composition for casting is
a powder (A) containing magnetic particles; a resin (B);
and a dispersant (C),
The content of the magnetic particles in the casting liquid composition is more than 70 vol% ,
The dispersant (C) contains a polymer compound,
The dispersant (C) is one or comprising two or more compounds,
A method for producing a molded article, wherein the content of the dispersant (C) in the casting liquid composition is 0.5 vol% or more and 10 vol% or less . A step of introducing the member to be sealed and the liquid composition for casting into the mold;
solidifying or curing the liquid casting composition,
The liquid composition for casting is
a powder (A) containing magnetic particles;
a resin (B);
and a dispersant (C),
Contains no solvents,
The content of the magnetic particles in the casting liquid composition is more than 70 vol%,
The content of the dispersant (C) in the casting liquid composition is 0.5 vol% or more,
A method for producing a molded article, wherein the dispersant (C) contains a compound containing at least one of a polyamino structure, a polyurethane structure, a polyester structure, and an ester structure. In the method for producing a molded article according to claim 13 or 14 ,
A method for producing a molded product, wherein in the introducing step, the casting liquid composition is poured into the mold at a pressure of 7000 hPa or less. In the method for producing a molding according to claims 1 to 5 ,
A method for producing a molded product, wherein in the introducing step, the casting liquid composition is poured into the mold under normal pressure. In the method for producing a molding according to any one of claims 13 to 16 ,
The member to be sealed is a method for manufacturing a molded article including a coil. a member to be sealed;
a sealing member that seals at least part of the member to be sealed;
The sealing member is
a powder (A) containing magnetic particles; a resin (B);
and a dispersant (C),
The content of the magnetic particles in the sealing member is over 70 vol% ,
The dispersant (C) contains a polymer compound,
The dispersant (C) is one or comprising two or more compounds,
The molding, wherein the content of the dispersant (C) in the sealing member is 0.5 vol% or more and 10 vol% or less . In the molding according to claim 18 ,
The member to be sealed is a molding including a coil. In the molding according to claim 19 ,
The coil is a molding including a conductive wire at least partially covered with a covering resin material. A molding according to any one of claims 18 to 20 ,
The molding, wherein the sealing member has a density of 3 g/cm ³ or more and 7 g/cm ³ or less.

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