JP2020013943A - Casting liquid composition, method for producing molded product, and molded product - Google Patents

Abstract

To provide a molded product having high magnetic permeability and excellent production efficiency.SOLUTION: A molded product 10 includes a sealed member 20 and a sealing member 30. The sealing member 30 seals at least a part of the sealed member 20. The sealing member 30 contains a powder (A) containing magnetic particles, a resin (B), and a dispersant (C). The content of the magnetic particles in the sealing member 30 exceeds 70 vol.%. The molded product 10 can be produced using, for example, a liquid composition.SELECTED DRAWING: Figure 1

Description

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

  As a method for sealing elements and components such as coils, for example, press molding in which a powdery sealing material and a member to be sealed are pressed at high pressure, or covering the member to be sealed with a fluid composition, There are molds that are solidified or cured.

  Patent Literature 1 describes that a mixed material of a soft magnetic powder and a resin is injected into a mold and cured to obtain a molded body of a composite material.

JP 2008-147403 A

  However, in the technique of Patent Document 1, when the content of the magnetic powder is increased, sufficient fluidity cannot be secured. As a result, it was difficult to obtain a molded body having high magnetic permeability.

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

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

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

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

  According to the present invention, it is possible to provide a molded product having high magnetic permeability and excellent production efficiency.

It is a figure which illustrates the structure of the molded object concerning a 1st embodiment. FIGS. 2A to 2C are diagrams illustrating the structure of a member to be sealed according to the first embodiment. It is a figure which illustrates the particle size distribution curve of the powder contained in the sealing member and composition concerning a 1st embodiment. (A) to (e) are diagrams illustrating a method for manufacturing a molded product according to the first embodiment. FIGS. 3A to 3D are diagrams illustrating a method for manufacturing a molded product according to the first embodiment. It is a figure for explaining a modification of a process of introducing a member to be sealed and a composition into a mold. (A) And (b) is a figure which illustrates the structure of the molded object which concerns on 2nd Embodiment. (A) to (c) are diagrams for explaining an example of a method for manufacturing a molded article 10 according to the second embodiment. FIG. 3 is a diagram showing a particle size distribution curve of powder 1. FIG. 4 is a diagram showing a particle size distribution curve of powder 2. FIG. 3 is a view showing a particle size distribution curve of powder 3; FIG. 4 is a diagram showing a particle size distribution curve of powder 4.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will not be repeated.

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

(First embodiment)
FIG. 1 is a diagram illustrating a structure of a molded article 10 according to the first embodiment. The molded article 10 includes a member to be sealed 20 and a sealing member 30. The sealing member 30 seals at least a part of the member 20 to be sealed. Further, the sealing member 30 includes a powder (A) containing magnetic particles, a resin (B), and a dispersant (C). And the content rate of the magnetic particles in the sealing member 30 exceeds 70 vol%. This will be described in detail below.

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

  Although the member to be sealed 20 is not particularly limited, in the present embodiment, the member to be sealed 20 includes a coil. In this case, the molded product 10 is a molded inductor. The molded article 10 can be, for example, a surface mount inductor or a reactor. The coil of the member to be sealed 20 has a structure in which, for example, a conductor is wound a plurality of times coaxially. The type of the member to be sealed 20 is not particularly limited, but is, for example, an edgewise coil. A part of the sealing member 30 functions as a magnetic core with respect to 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 the inductor. The member to be sealed 20 may be entirely covered and sealed with the sealing member 30, or only a part may be sealed with the sealing member 30. The state in which only a part of the member to be sealed 20 is sealed with the sealing member 30 is, for example, a state in which a part is covered with the sealing member 30 and embedded in the sealing member 30. Say.

  In the example shown in FIGS. 2A and 2B, the sealing member 30 includes a first member 31 and a second member 32. The first member 31 and the second member 32 are integrally joined. The member to be sealed 20 includes an annular portion 201 and a wiring portion 202. The annular portion 201 is a portion in which the conductor is wound a plurality of times around the coaxial axis, and functions as a coil. The conductor is not particularly limited, but is, for example, a rectangular conductor and is coated with an insulating material. That is, the coil includes a conducting wire at least partially covered with the covering resin material. The wiring section 202 is electrically connected to the annular section 201. For example, both ends of one winding form a wiring portion 202, and a portion between the wiring portions 202 at both ends forms an annular portion 201.

  The second member 32 is a plate-like member having a notch. The annular portion 201 is located on the second member 32 and is covered with the first member 31. The annular portion 201 is located between the first member 31 and the second member 32 and is sealed. On the other hand, at least a part of each wiring portion 202 is exposed outside the sealing member 30. The exposed portion surrounds the second member 32. Specifically, the wiring part 202 covers a part of the surface of the second member 32 on the side opposite to the annular part 201 side. In addition, a part of the wiring section 202 is covered with the solder 203 with the insulating coating removed, and constitutes a terminal of the inductor. However, the structure of the molded product 10 is not limited to the example shown in FIG.

  Further, as described later, since the molded article 10 can be produced using a liquid composition, the thickness of the sealing member 30 can be reduced. Consequently, the volume of the portion of the member to be sealed 20 that is covered with the sealing member 30 can be increased.

  Next, the liquid composition according to the present embodiment will be described. The molded article 10 according to the present embodiment can be manufactured using the following liquid composition.

  The liquid composition according to the present embodiment is a liquid composition for casting. The liquid composition contains a powder (A) containing magnetic particles, a resin (B), and a dispersant (C). Further, the content of the magnetic particles in the liquid composition is more than 70 vol%. The method for adjusting the liquid composition described below is an example. The term “liquid” means that the material has fluidity at a temperature at which the liquid is poured into the mold.

  As described above, the powder (A) contains magnetic particles. In particular, the magnetic particles preferably include soft magnetic particles. In addition, the magnetic particles include 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. Preferably, the magnetic particles include at least one, and more preferably, the magnetic particles include Fe (iron). Specific examples of the magnetic particles include sendust and iron-based amorphous alloy. Further, the powder may contain, as particles other than the magnetic particles, for example, one or more selected from the group consisting of silica, alumina, aluminum nitride, rubber particles, and PTFE. 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. Further, with respect to the powder composed of a conductive substance, an insulating film may be formed on the particles. In this case, the dielectric strength of the liquid composition increases. On the other hand, the particles need not have an insulating film formed thereon.

  The volume content of the magnetic particles with respect to the sealing member 30, that is, the volume content of the magnetic particles with respect to the composition is preferably more than 70 vol%, more preferably 71 vol% or more, and further preferably 72 vol% or more. preferable. By thus increasing the filling rate of the magnetic particles, for example, when the molded product 10 is an inductor, the magnetic permeability of the magnetic core can be increased. 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, and more preferably 77 vol% or less. preferable.

  Further, 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, More preferably, it is 72 vol% or more. The composition, that is, the volume content of the powder (A) in the sealing member 30 is, for example, 95 vol% or less, and is preferably 85 vol% or less, and more preferably 77 vol% or less from the viewpoint of lowering the viscosity. 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 or cured product of the composition are, for example, JIS. It can be measured as follows in accordance with K 7250 (2006) "Plastics-Determination of Ash Content". First, the solidified or cured product 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 calculated as 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 the powder (A) is represented by {volume of powder (A) / (volume of powder (A) + volume of combustible component)} × 100. Here, when particles other than the magnetic particles are not contained in the powder (A), 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 product of the composition is heated to 600 ° C. in a muffle furnace to remove combustible components, and the remaining powder (A) Using a magnet, magnetic particles and others can be sorted. The volume of the magnetic particles is determined by dividing the weight of the obtained magnetic particles by the true density of the magnetic particles. Further, the volume of the particles other than the magnetic particles is 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 the magnetic particles is represented by {volume of magnetic particles / (volume of magnetic particles + volume of combustible component + volume of particles other than magnetic particles)} × 100.

  Further, the weight content of the composition, that is, the powder (A) in 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 composition, that is, the powder (A) in the sealing member 30 is, for example, 97 wt% or less, and more preferably 95 wt% or less from the viewpoint of reducing the viscosity.

  The powder (A) may include two or more powders having different median diameters D50 from each other. By doing so, the particles in the composition and the sealing member 30 are filled at a high density. According to this embodiment, even when the powder (A) has a high filling property in the composition, the composition has fluidity and a molded article can be obtained efficiently.

  Here, at least one of the powders contains magnetic particles. Further, the respective powders may have different compositions, or may have the same composition.

  The magnetic particles contained in the powder (A) are produced by, for example, any one of 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 be manufactured using another method, specifically, for example, a disk atomizing method, a rotating electrode method, a carbonyl method, a chemical reduction method, or an electrolytic method. In addition, each powder contained in the powder (A) may be manufactured using different methods, or may be manufactured using the same method.

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

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

  The relationship between the first peak 51 and the second peak 52 is not particularly limited, but the difference between the particle size of the first peak 51 and the particle size of the second peak 52 may be 5 μm or more from the viewpoint of improving the filling property. Preferably, it is 50 μm or more, more preferably 60 μm or more. Further, from the same viewpoint, 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 1/3 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. In this case, particles having a relatively small diameter do not increase more than necessary, and as a result, the fluidity of the composition does not easily decrease.

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

  The height of the second peak 52 is, for example, not less than ５ times and not more than twice the height of the first peak 51. Between the first peak 51 and the second peak 52, there may be another peak or a plurality of minimum values. The first peak 51 is preferably, for example, 30 μm or more and 300 μm or less, and more preferably 50 μm or more and 150 μm or less. Further, the second peak 52 is preferably, for example, 1 μm or more and 50 μm or less, 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, and still 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, and 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, and even more preferably 100 μm or less. Further, D90 of the powder (A) is preferably at least 10 μm, more preferably at least 50 μm, even more preferably at least 100 μm. On the other hand, D90 of the powder (A) is preferably 500 μm or less, more preferably 300 μm or less, and still more preferably 200 μm or less. The average diameter of the powder (A) is preferably 5 μm or more, more preferably 10 μm or more, and further 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, and further preferably 100 μm or less. By setting D10, D50, D90, and the average diameter of the powder (A) in the above ranges, a low-viscosity liquid composition can be obtained using the dispersant (C).

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

  The shape of the particles contained in the powder (A) is not particularly limited, and may be spherical, crushed, or the like. From the viewpoint of improving the dispersibility in the composition, the powder (A) preferably contains spherical particles. Since the spherical particles have a small surface area, the amount of resin to be covered by the particles in order to secure a dispersed state is small. Therefore, even when the content of the powder (A) is high, aggregation in the composition can be avoided. Note that the spherical particles need not necessarily be true spheres.

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

  Examples of the polyolefin include polyethylene and polypropylene. Examples of polystyrene include acrylonitrile styrene, styrene-butadiene-acrylonitrile copolymer (ABS), and the like. Examples of the polyamide include acrylic, polycarbonate, modified polyphenylene ether, 6-nylon, aromatic polyamide, and aliphatic polyamide. Examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and a liquid crystal polymer. Examples of the imide-based resin include polyamide imide, polyimide, and bismaleimide. Examples of the fluororesin include polytetrafluoroethylene (PTFE) and copolymers thereof (PFA, ETFE, FEP, etc.), polychlorotrifluoroethylene, polyvinylidene fluoride (PVDF), and the like.

  It is preferable that the thermosetting resin, the moisture-curable resin, and the photo-curable resin are liquid at room temperature. From the viewpoint of improving the relative magnetic permeability, the volume content of the resin (B) with respect to the composition is preferably 40 vol% or less, more preferably 30 vol% or less. On the other hand, from the viewpoint of improving the fluidity of the composition, the volume content of the resin (B) with respect to the composition is preferably at least 10 vol%, more preferably at least 15 vol%.

  The dispersant (C) is not particularly limited, but is, for example, a polymer. The molecular weight of the dispersant (C) is not particularly limited, but the dispersant (C) preferably contains at least one of a low molecular compound and a high molecular compound, and more preferably contains a high molecular 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 compound of block copolymerization. The dispersant (C) preferably contains, for example, a compound having a molecular shape of at least one of a comb shape and a hyperbranched structure, and more preferably a comb shape compound. The dispersant (C) preferably contains, for example, a compound having a molecular structure of at least one of a polyamino structure, a polyurethane structure, a polyester structure, and an ester structure, and more preferably contains a compound having a polyamino structure.

  From the viewpoint of reducing the viscosity, the dispersant (C) is a group consisting of a polycarboxylate, a polyaminoamide salt, an alkyl ammonium salt, an alkylol ammonium salt, a phosphate ester salt, an acrylic block copolymer, and a polymer salt. It is preferable to include one or more compounds selected from the group consisting of:

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

  Specific examples of the dispersant (C) include BYK-Chemie's ANTI-TERRA-U100 (unsaturated polyaminoamide and low molecular weight polyester acid salt, amine value 35 mg KOH / g, acid value 50 mg KOH / g), BYK-9076 (Alkyl ammonium salt of polymer copolymer, amine value 44 mg KOH / g, acid value 38 mg KOH / g), BYK-9077 (polymer copolymer having a pigment affinity group, amine value 48 mg KOH / g), DISPERBYK-108 (Hydroxyl-containing carboxylic acid ester having an affinity group for pigment, amine value 71 mgKOH / g), DISPERBYK-145 (phosphate ester salt of high molecular weight copolymer having pigment affinity group, amine value 71 mgKOH / g, acid value 76mgKOH / g), DISPERBYK-2055 (face Copolymer having an affinity group, amine value 40 mgKOH / g), DISPERBYK-2152 (hyperbranched polyester), DISPERBYK-2155 (block copolymer having a basic group having a pigment affinity, amine value 48 mgKOH / g), DISPERBYK -200 (polymer copolymer having a pigment affinity group) or the like can be used. In addition, as a dispersing agent (C), it can be used without being limited to the compound manufactured by Big Chemie.

  The curing speed of the composition can 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 cover the surface with a resin having a certain thickness. That is, when the particles do not cover the resin at all, the frictional force between the particles hinders the flow. As the content of the powder (A) increases, the amount of the resin covered by the particles gradually decreases, which causes an increase in friction. As a result, the viscosity of the composition increases. In addition, as the distance between the particles becomes shorter, the case where the particles come into contact with each other (aggregation) may also occur. When agglomeration occurs, the agglomerated particles behave as one magnetic particle having a large particle size, and may increase the magnetic flux density. However, since the density of the magnetic particles is not high, magnetic saturation occurs at a low coil current, and it is presumed that the usable current region of the inductor becomes small.

  The composition according to the present embodiment can ensure fluidity even when the content of the powder (A) is high by including the dispersant (C). By increasing the content of the magnetic particles, the magnetic permeability of the sealing member 30 can be increased. When the molded article 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 preferably 1.5 vol% or more from the viewpoint of effectively lowering the viscosity. More preferred. Further, the content of the dispersant (C) is preferably 10 vol% or less, more preferably 5 vol% or less, and more preferably 3 vol% or less from the viewpoint of effectively lowering the viscosity and improving the relative magnetic permeability. Is more preferable.

  When a magnetic core of an inductor is formed using a composition containing a resin and 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, when the content of the powder is increased, the fluidity of the composition is impaired, and the moldability and the production efficiency are reduced.

  In contrast, the composition according to the present embodiment can maintain the fluidity of the composition in a high state while increasing the powder content in the composition by including the dispersant.

  The composition may further contain additives other than the powder (A), the resin (B), and the dispersant (C) as necessary. Examples of the additives include a curing agent, a coupling agent, a defoaming agent, and a release agent. Examples include a mold agent, a flame retardant, an antioxidant, and an ion adsorbent. In addition, the composition may further include a solvent, if necessary. However, the composition according to the present embodiment preferably does not contain a coupling agent such as a silane coupling agent or a solvent from the viewpoint of cost reduction.

The composition according to the present embodiment has a pourable viscosity at the temperature at which it is poured into a mold. For example, the composition according to the present embodiment preferably has a viscosity V _L1 at 25 ° C. measured at 60 minutes after the start of rotation with a viscometer at a rotation speed of 0.3 rpm is 1500 Pa · s or less. Then, injection into the mold at room temperature is possible. From the viewpoint of production efficiency and improvement of formability of molded articles 10, it preferably has a viscosity _{V L1} or less 1200 Pa · s, more preferably not more than 1000 Pa · s. 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 at 50 ° C. measured at 60 minutes after the start of rotation with a viscometer at a rotation speed of 0.3 rpm of 500 Pa. S or less, and more preferably 300 Pa · s or less. On the other hand, the viscosity _{V L2} is, for example, 30 Pa · s or more.

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

Further, 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, a state in which the composition can be effectively cast can be realized by heating the composition. 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 at 25 ° C. measured at 10 minutes after the start of rotation under a condition of a rotation number of 0.3 rpm with a viscometer at 3000 Pa · s or less, preferably 1500 Pa · s. S or less, more preferably 1000 Pa · s or less. On the other hand, the viscosity _{V S1} is, for example, 200 Pa · s or more.

The composition according to the present embodiment preferably has a viscosity V _S2 at 50 ° C. measured 10 minutes after the start of rotation under a condition of a rotation number of 0.3 rpm with a viscometer at 400 Pa · s or less, and 300 Pa or less. S or less, more preferably 200 Pa s or less. On the other hand, the viscosity _{V S2} is, for example, 40 Pa · s or more.

From the viewpoint of ensuring the casting time, the value represented by _VL1 / _VS1 is preferably 0.3 or more, and more preferably 0.6 or more. Further, the value represented by _VL2 / _VS2 is preferably 0.5 or more, and more preferably 0.7 or more. On the other hand, from the viewpoint of shortening curing time, the value represented by V _{L1 /} V _S1 is more preferably 1 or less and preferably 0.9 or less. Further, the value represented by _VL2 / _VS2 is preferably 1.2 or less, more preferably 1 or less.

  The relative magnetic permeability of the solidified or cured product of the composition according to this embodiment at 10 kHz can be, for example, 22 or more, preferably 25 or more, and more preferably 30 or more. 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 the conditions of 500 mV and 10 kHz. The relative magnetic permeability can be controlled by adjusting the components and composition of the composition, and the conditions for solidification or curing.

  The relative magnetic permeability most strongly depends on the material of the powder (A), but also depends on the packing state and dispersion state of the particles, the particle size distribution, and the state of voids in the solidified and cured products. For example, when agglomeration of magnetic particles occurs, the agglomerated particles behave as one large-diameter magnetic particle, increasing the magnetic flux density. Then, the magnetic flux density with respect to the same external magnetic field as in the case where no aggregation occurs is increased, so that the magnetic permeability is increased. On the other hand, even when the magnetic permeability is increased in this way, it is assumed that magnetic saturation occurs at a low coil current when the amount of the magnetic substance is not necessarily large.

  The present composition may or may not have thixotropic properties. At the time of mixing, the mixing container may be subjected to vibration, heating, or degassing by reducing the pressure. Then, the voids contained in the obtained molded article 10 can be further reduced.

  4 (a) to 4 (e) and FIGS. 5 (a) to 5 (d) are views illustrating a method for manufacturing the molded article 10 according to the present embodiment. The present 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 an “introducing step”), and a step of solidifying or curing the composition 300. This production method can be realized using the composition 300 as described above. That is, the composition 300 is a liquid composition for casting, and includes a powder (A) containing magnetic particles, a resin (B), and a dispersant (C). And the content rate of the magnetic particles in the composition 300 is more than 70 vol%. This will be described in detail below.

  First, as shown in FIG. 4A, the composition 300 that has been degassed under reduced pressure is poured into a molding die 41, and the composition 300 is solidified or cured. Then, the second member 32 is obtained as shown in FIG. Next, as shown in FIG. 4C, the member to be sealed 20 is arranged on the second member 32. At this time, a portion of the member to be sealed 20 that will become a terminal is removed from the insulating coating, and is coated with the solder 203. Next, as shown in FIGS. 4D and 4E, the wiring portion 202 connected to the annular portion 201 is wound around the second member 32 and fixed. FIG. 4E corresponds to a diagram of FIG. 4D viewed from the left.

  On the other hand, as shown in FIG. 5A, the composition 300 that has been defoamed under reduced pressure is poured 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. 5C, the composition 300 is solidified or cured while the member to be sealed 20 is inserted into the composition 300. After the sealing member 30 is solidified or hardened, the molded product 10 is obtained by removing the mold as shown in FIG. The surface of the molded product 10 may be covered with another resin.

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

  In the steps shown in FIGS. 4 to 6, when the resin contained in the composition 300 is a thermosetting resin, for example, when injecting the composition 300 into a mold, the temperature of the mold is set lower than the curing temperature of the resin. Thereafter, the temperature of the mold may be set to a temperature equal to or higher than the curing temperature of the resin. Note that even when the temperature of the mold is equal to or higher than the curing temperature, the composition 300 can be spread inside the mold before the composition 300 solidifies, depending on the temperature of the composition 300 at the time of injection.

  When the resin contained in the composition 300 is a thermoplastic resin, for example, the temperature of the mold may be set to be equal to or higher than the softening temperature when the composition 300 is injected into the mold, and then the temperature of the mold may be set to be lower than the softening temperature. Even when the temperature of the mold is lower than the softening point, the composition 300 can be spread inside the mold before the composition 300 solidifies, depending on the temperature of the composition 300 at the time of injection.

  In this method, as described above, the composition 300 includes a dispersant. For this reason, 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, for example, normal pressure, high pressure, or reduced pressure. For example, the composition 300 can be poured into the mold 42 at normal pressure. Specifically, the composition 300 can be poured only by gravity into the mold 42 under the atmospheric pressure where the upper part of the molding space is open. In addition, even when the composition 300 is injected from the injection port 421, it is not necessary to particularly push the composition 300 into the molding space at a high pressure or to reduce the pressure in the molding space to draw the composition 300. However, there is no problem if the inside of the molding space is depressurized or the composition 300 is pushed into the molding space by applying pressure in order to improve the production efficiency.

  In the present method, the composition 300 may be heated when 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, when the fluidity is high even in a state where the composition 300 is not heated, the composition 300 need not be heated.

  Further, in the present method, after the step of introducing the composition 300 into the molding die 42, and before the step of solidifying or curing the composition 300, the molding die 42 into which the composition 300 and the member to be sealed 20 have been introduced. Alternatively, vibration may be applied, heating may be performed, or defoaming may be performed under reduced pressure. Then, the voids contained in the obtained molded article 10 can be further reduced.

  When a coil or the like is sealed by performing press molding accompanied by a high-pressure press in the production of a molded product, a pressure balance may be lost between upper and lower portions, and a crack may be generated. In addition, distortion during molding may cause deterioration in electromagnetic characteristics. On the other hand, according to the present method, the molded article 10 can be manufactured not by press molding but by molding without high-pressure pressing. Therefore, generation of cracks and deterioration of characteristics can be suppressed. In addition, no press equipment 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.

  Further, since the composition 300 according to the present embodiment has fluidity, it can enter a narrow gap in the molding space of the mold 42. Therefore, the thickness of the sealing member 30 can be reduced. For example, the minimum value of the 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 the above-described press molding, while almost no gap is present in the sealing member, the sealing member 30 of the molded product 10 obtained by molding such as the method according to the present embodiment includes: There are voids to such an extent that there is no problem in the quality of the molded product 10. Further, when the molded article 10 is an inductor, the molded article 10 obtained by the molding according to the present method has less crystal distortion and smaller iron loss than the molded article obtained by the press molding. Further, the self-resonant frequency of the molded product 10 can be set to, for example, 1000 kHz or more.

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. But the density of the sealing member 30 is particularly limited, is preferably 3 g / cm ³ or more, more preferably 5 g / cm ³ or more, further preferably 5.4 g / cm ³ or more. On the other hand, the density of the sealing member 30 is, for example, 7 g / cm ³ or less. The density of the sealing member 30 can be measured by, for example, the Archimedes method.

  Next, the operation and effects of the present embodiment will be described. According to this embodiment, the composition and the sealing member contain the dispersant (C). For this reason, the fluidity of the composition can be secured while increasing the powder filling rate. Therefore, the powder content of the sealing member 30 can be increased. Further, since the sealing member 30 can be molded, the production efficiency of a molded product such as the sealing member 30 is high.

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

  In the present embodiment, the member to be sealed 20 includes a coil 21 and a pedestal 22. The coil 21 includes an annular part 211 and a wiring part 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 another material. The pedestal 22 includes a bottom plate 222 and a support 221 having one end fixed to the bottom plate 222. The support portion 221 is located between the bottom plate portion 222 and the annular portion 211. In the member to be sealed 20 before being sealed by the sealing member 30, the support portion 221 supports the annular portion 211 at the other end. At least some of the wiring portions 212 on both sides of the annular portion 211 are exposed outside the sealing member 30. The exposed portion surrounds the bottom plate portion 222. Specifically, the wiring part 212 covers a part of the surface of the bottom plate part 222 on the side opposite to the annular part 211 side. In addition, a part of the wiring portion 212 is covered with the solder 213 with the insulating coating removed, and constitutes a terminal of the inductor.

  FIGS. 8A to 8C are views for explaining an example of a method for manufacturing the molded article 10 according to the present embodiment. In this method, as shown in FIG. 8A, first, the coil 21 is fixed to the pedestal 22, and the member to be sealed 20 is obtained. FIG. 8A corresponds to FIG. 4D of the first embodiment. Next, as shown in FIG. 8B, the composition 300 and the member to be sealed 20 that have been defoamed under reduced pressure are introduced into a molding die 42. After solidifying or curing the composition 300 in the state as shown in FIG. 8C, the molded article 10 is obtained by removing the mold. In the present 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 the conditions described in the first embodiment.

  The molded article 10 according to the present embodiment can be manufactured without separately using the second member 32 made of a solidified or cured product of the composition 300 as in the first embodiment. Further, since the base 22 is a resin member, the molded product 10 can be reduced in weight and cost.

  According to this embodiment, the same operation and effect as those of the first embodiment can be obtained.

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

[Examples 1 to 12, Comparative Example]
<Preparation of composition>
The compositions according to Examples 1 to 12 and the composition according to the comparative example 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 type” is 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 resins (B) and dispersants (C) used in the compositions of Examples 1 to 12 and Comparative Examples are as follows.
Resin 1: Bisphenol A type epoxy resin dispersant containing a curing agent (acid anhydride) 1: DISPERBYK-145 manufactured by BYK-Chemie

  In preparing each composition according to Examples 1 to 12 and Comparative Example, first, as shown in Table 3, two kinds of fillers were mixed to obtain a powder. Next, the powder, the resin, and the 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 under the conditions of 4 kPa and 30 minutes, and used for the following measurement and production of an inductor.

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

  The compositions of Examples 4 and 10 did not have fluidity at room temperature, but had fluidity at 50 ° C. Then, the composition was poured into a molding die at normal pressure while being heated to 50 ° C. Then, 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 is better in Example 5 than in Example 4 because of the presence or absence of fluidity at room temperature. .

  The composition according to the comparative example did not contain a dispersant. As a result, sufficient fluidity could not be obtained even at room temperature or at 50 ° C., and an inductor having sufficient quality as a product could not be produced by molding.

<Particle size distribution>
The particle size distribution of the powders 1 to 4 was measured. The measurement was performed using a laser diffraction / scattering type particle size distribution measuring device (LA-950V2 manufactured by Horiba, Ltd.). 9 to 12 show the particle size distribution curves of the powders 1 to 4, respectively.

  The particle size distribution curve of each particle showed a peak corresponding to the particle size of each filler type. Of the two peaks of each powder, when the peak with the larger particle size is defined as the first peak and the peak with the smaller particle size is defined as the second peak, each powder has the particle size of the first peak and the second peak. The difference from the particle size of the two peaks was 60 μm or more and 100 μm or less. Table 3 shows the particle diameter of the first peak, the particle diameter of the second peak, and the peak ratio (peak value of the second peak / peak value of the first peak). In the powders 2 to 4, the peak value of the first peak was larger than the peak value of the second peak. It is considered that 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 that the peak of the particle size distribution of the filler A is broad.

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

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

  The viscosity measured with a viscometer tends to decrease mainly with the passage of time from the start of rotation, and was almost stable at 60 minutes from the start of rotation. It was also confirmed that there was 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, the higher the viscosity measured after 10 minutes, the higher the viscosity measured after 60 minutes.

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

<Formability evaluation>
The moldability of each composition of Examples 1 to 12 was evaluated. Specifically, a cured product of the composition was partially cut out from the inductor prepared as described above with each composition, and used as a measurement sample. Then, the moldability of the obtained measurement sample was evaluated as follows. First, a calculated value d1 of the density of the composition was calculated based on the components and the composition of the composition. On the other hand, the measured value d2 of the density of the measurement sample was measured by the Archimedes method. From the obtained d1 and d2, a value of d2 / d1 was calculated. The results are shown in Tables 8 and 9.

  Since the measured value d2 becomes smaller than the calculated value d1 when there are voids and bubbles inside the cured product, it can be said that the larger the value of d2 / d1, the smaller the number of voids and bubbles inside the cured product. We can evaluate 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 more excellent in moldability than the composition of Example 4. Also, comparing the results of Examples 7 to 10 in which the content of each component was changed, the compositions of Examples 7 to 9 were more excellent in moldability than the composition of Example 10. .

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

  The relationship between the formability and the relative magnetic permeability will be discussed below. Among the above examples, Examples 1 to 4 are different from each other in the content of the magnetic particles. In Examples 1 to 3, the relative magnetic permeability increases as the measured value d2 of the density increases. On the other hand, in Example 4, the relative magnetic permeability was improved despite the small measured value d2. This is considered to be caused by aggregation of magnetic particles, and it is presumed that magnetic saturation occurs at a low coil current. Therefore, as in Examples 1 to 3, it is more preferable to increase the formability to achieve a high measured value d2 and, as a result, to improve the relative magnetic permeability. In Examples 1 to 3, it is considered that the individual magnetic particles are dispersed particularly well in the composition.

[Examples 13 to 26]
<Preparation of composition>
The compositions according to Examples 13 to 26 were prepared in the same manner as in Example 1. The composition of each composition is as shown in Table 10, and the dispersant (C) used is as shown in Table 11. In addition, all the dispersants (C) shown in Table 11 are manufactured by Big Chemie. In Table 10, "Powder 1" and "Resin 1" are as described above for Example 1 and the like. 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 according to Examples 13 to 26 had fluidity at room temperature (25 ° C.) and could be poured into a mold at normal pressure. In producing the inductor, each composition was cured at 130 ° C. for 3 hours after casting.

<Viscosity of composition>
The viscosity of the composition according to each of Examples 13 to 26 was measured. The measurement was carried out using a digital B-type viscometer (BASE PLUS L, manufactured by Atago Co., Ltd.) under the following conditions. The viscosity 10 minutes after the start of rotation for measurement was read as a measured value. The results are summarized in Table 11. The viscosity was measured under conditions 1 corresponds to a viscosity V _S1, viscosity measured at condition 2 corresponding to a viscosity V _S2.
Condition 1: Measurement temperature 25 ° C, rotation speed 0.3 rpm
Condition 2: Measurement temperature 50 ° C., rotation speed 0.3 rpm
Condition 3: Measurement temperature 50 ° C., rotation speed 3 rpm

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

  As described above, the embodiments of the present invention have been described with reference to the drawings. However, these are merely examples of the present invention, and various configurations other than the above can be adopted.

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

Claims (20)

A powder (A) containing magnetic particles, a resin (B),
A dispersant (C),
The liquid composition for casting, wherein the content of the magnetic particles is more than 70 vol%. The liquid composition for casting according to claim 1,
A casting liquid composition having a viscosity at 25 ° C. of 100 Pa · s or more and 1500 Pa · s or less, which is measured by a viscometer at a rotation speed of 0.3 rpm after 60 minutes from the start of rotation. The liquid composition for casting according to claim 1 or 2,
A casting liquid composition having a viscosity at 50 ° C. of 30 Pa · s or more and 500 Pa · s or less, measured by a viscometer at a rotation speed of 0.3 rpm after 60 minutes from the start of rotation. In the casting liquid composition according to any one of claims 1 to 3,
When the viscosity at 25 ° C. is V _L1 and the viscosity at 50 ° C. is V _L2 and the viscosity at 50 ° C. is V _L1 , which is measured 60 minutes after the start of rotation under the condition of a rotation number of 0.3 rpm with a viscometer, it is expressed as V _L1 / V _L2 The liquid composition for casting has a value of 2 or more and 7 or less. In the casting liquid composition according to any one of claims 1 to 4,
A liquid composition for casting, wherein D10 of the powder (A) is 1 μm or more and 50 μm or less, median diameter D50 is 5 μm or more and 300 μm or less, and D90 is 10 μm or more and 500 μm or less. The casting liquid composition according to any one of claims 1 to 5,
A liquid casting composition in which the solidified or cured product of the liquid casting composition has a relative magnetic permeability of 22 or more at 10 kHz. The casting liquid composition according to any one of claims 1 to 6,
The dispersant (C) is a liquid composition for casting containing a polymer compound. The casting liquid composition according to claim 7,
The dispersant (C) is selected from the group consisting of a polycarboxylate, a polyaminoamide salt, an alkyl ammonium salt, an alkylol ammonium salt, a phosphate ester salt, an acrylic block copolymer, and a polymer salt. A liquid casting composition comprising two or more compounds. The liquid composition for casting according to any one of claims 1 to 8,
The liquid composition for casting, wherein the content of the dispersant (C) is 0.5 vol% or more and 10 vol% or less. The liquid composition for casting 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), polyphenylenesulfide (PPS) ), An imide-based resin, and a fluororesin, a casting liquid composition containing one or more resins selected from the group consisting of: In the casting liquid composition according to any one of claims 1 to 10,
The liquid composition for casting, wherein the magnetic particles include soft magnetic particles. The casting liquid composition according to any one of claims 1 to 11,
The liquid composition for casting, wherein the magnetic particles include iron. A step of introducing the sealed member and the casting liquid composition into a mold,
Solidifying or curing the casting liquid composition,
The casting liquid composition,
A powder (A) containing magnetic particles, a resin (B),
A dispersant (C),
A method for producing a molded product, wherein the content of the magnetic particles in the liquid composition for casting is more than 70 vol%. The method for producing a molded product according to claim 13,
In the step of introducing, a method for producing a molded product in which the liquid composition for casting is poured into the molding die at a pressure of 7000 hPa or less. In the method for producing a molded product according to claim 14,
In the step of introducing, a method for producing a molded product in which the liquid composition for casting is poured into the molding die at normal pressure. The method for producing a molded product according to any one of claims 13 to 15,
The method for producing a molded product in which the member to be sealed includes a coil. A member to be sealed;
A sealing member for sealing at least a part of the member to be sealed,
The sealing member,
A powder (A) containing magnetic particles, a resin (B),
A dispersant (C),
A molded product in which the content of the magnetic particles in the sealing member exceeds 70 vol%. The molded article according to claim 17,
The sealed member is a molded product including a coil. The molded article according to claim 18,
A molded product including a conductive wire at least a part of which is coated with a coating resin material. The molded article according to any one of claims 17 to 19,
A molded product in which the density of the sealing member is 3 g / cm ³ or more and 7 g / cm ³ or less.

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