JP2019212664A - Resin composition for forming magnetic member, magnetic member, coil, manufacturing method of magnetic member, and kit for forming magnetic member - Google Patents

Abstract

To provide a resin composition for forming a magnetic member, which has good fluidity at the time of formation and has good heat resistance of a cured product obtained by the formation.SOLUTION: There is provided a resin composition for forming a magnetic member including an epoxy resin, aromatic diamine, and magnetic particles. There is also provided a magnetic member formed from the resin composition. There is also provided a coil including the magnetic member as a magnetic core or an exterior member. In addition, there is provided a manufacturing method of a magnetic member of injecting a melt of the resin composition into a mold by using a transfer molding apparatus to obtain a magnetic member in which the melt is hardened. The aromatic diamine preferably has a melting point of 160°C or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin composition for molding a magnetic member, a magnetic member, a coil, a method for producing the magnetic member, and a magnetic member molding kit.

  Attempts to manufacture magnetic members such as magnetic cores and exterior members of coils (sometimes called reactors, inductors, etc. depending on applications and purposes) by applying resin molding technology are known. ing.

  For example, in Patent Document 1, a coil, a magnetic core (inner core Mi), and a potting material are cast and cured by pouring a mixed material of soft magnetic powder and resin as a potting material. It is described that a reactor in which an exterior member (outer core Mo) that accommodates them can be integrated can be obtained (particularly, see paragraph 0071, FIG. 3 and the like). Patent Document 1 describes that the exterior member can be obtained by casting and curing a potting material under atmospheric pressure or a predetermined low pressure (particularly, see paragraph 0045).

Further, Patent Document 2, a soft magnetic powder, a magnetic material containing a resin enclosing in a dispersed state the soft magnetic powder, soft magnetic powder has an average particle diameter D ₁ of 50~500μm a coarse powder, the average particle diameter D ₂ has been described magnetic material containing a fine powder of 0.1 to 30 [mu] m. Patent Document 2 describes that these two kinds of fine powders are mixed with a thermoplastic nylon resin, melted, and injected into a mold by an injection molding method to obtain a molded product. .

JP 2014-75596 A International Publication No. 2016/043025

  When manufacturing (molding) a magnetic member by applying a resin molding technique, it is naturally preferable to use a resin composition having good fluidity. A resin composition having good fluidity can be easily injected into a mold and can easily form a complicated shape. In particular, when the resin composition contains magnetic particles, the fluidity tends to decrease. Therefore, it is important to improve the fluidity.

  The flow rate of the resin composition is related to the fluidity of the molding resin composition. In this respect, for example, if the number of functional groups possessed by the resin is reduced, the curing rate is reduced and the fluidity as the resin composition is improved.

However, a design that reduces the number of functional groups of the resin usually makes the crosslinks loose, and as a result, lowers the glass transition temperature of the cured product of the resin composition.
The low glass transition temperature of the cured product of the resin composition means that the heat resistance of the cured product is low (the cured product is vulnerable to heat). Since the coil in the electric / electronic field is required to have high reliability in a high temperature environment, it is a problem that the cured product (magnetic member) is vulnerable to heat.
However, if the resin composition is designed so that the glass transition temperature of the cured product is increased, the moldability may be reduced.
In other words, in manufacturing a magnetic member by applying a resin molding technique, there are trade-off issues between good fluidity during molding and heat resistance of a cured product (magnetic member) obtained by molding.

  The present invention has been made in view of such circumstances. An object of this invention is to provide the resin composition for magnetic member shaping | molding with the favorable fluidity | liquidity at the time of shaping | molding, and the heat resistance of the hardened | cured material obtained by shaping | molding being favorable.

  As a result of various studies, the inventors of the present invention have completed the invention provided below, and have achieved the above object.

According to the present invention,
Provided is a resin composition for molding a magnetic member, which includes an epoxy resin, an aromatic diamine, and magnetic particles.

Moreover, according to the present invention,
A magnetic member molded from the above resin composition is provided.

Moreover, according to the present invention,
A coil provided with the above magnetic member as a magnetic core or an exterior member is provided.

Moreover, according to the present invention,
A method for producing a magnetic member is provided, in which a melt of the resin composition is poured into a mold using a transfer molding apparatus to obtain a magnetic member in which the melt is cured.

Moreover, according to the present invention,
Including an epoxy resin and an aromatic diamine,
There is provided a resin composition used for mixing with magnetic particles to form a magnetic member.

Moreover, according to the present invention,
A mixing step of mixing the resin composition and the magnetic particles to obtain a mixture;
And a molding step of melting and injecting the mixture into a mold and molding the mixture.

Moreover, according to the present invention,
A first component comprising an epoxy resin and an aromatic diamine;
There is provided a magnetic member molding kit comprising a second component containing magnetic particles.

ADVANTAGE OF THE INVENTION According to this invention, the fluidity | liquidity at the time of shaping | molding is excellent, and the heat resistance of the hardened | cured material obtained by shaping | molding provides the resin composition for magnetic member shaping | molding.
(Hereinafter, the fluidity at the time of molding is also simply referred to as “fluidity.” The heat resistance of the cured product obtained by molding is also simply referred to as “heat resistance”.)

It is a figure which shows typically the coil provided with a magnetic core. It is a figure which shows typically the coil (an aspect different from the thing of FIG. 1) provided with a magnetic core. It is a figure which shows an integrated inductor typically.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
In order to avoid complications, (i) when there are a plurality of identical components in the same drawing, only one of them is given a reference, and all are not attached, or (ii) 2 and later, the same components as in FIG. 1 may not be denoted again.
All drawings are for illustrative purposes only. The shape and dimensional ratio of each member in the drawings do not necessarily correspond to an actual article.

In this specification, the term “substantially” means that it includes a range that takes into account manufacturing tolerances, assembly variations, and the like, unless otherwise specified.
In the present specification, the notation “ab” in the description of the numerical range represents a range from a to b unless otherwise specified. For example, “1 to 5% by mass” means “1 to 5% by mass”.

In the notation of a group (atomic group) in this specification, the notation which does not describe substitution or non-substitution includes both those having no substituent and those having a substituent. For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).
The notation “(meth) acryl” in the present specification represents a concept including both acrylic and methacrylic. The same applies to similar notations such as “(meth) acrylate”.
In the present specification, the term “organic group” means an atomic group obtained by removing one or more hydrogen atoms from an organic compound unless otherwise specified. For example, the “monovalent organic group” represents an atomic group obtained by removing one hydrogen atom from an arbitrary organic compound.

<Resin composition>
The resin composition of the present embodiment is for molding a magnetic member, and includes an epoxy resin, an aromatic diamine, and magnetic particles.

The reason why both moldability and heat resistance can be improved by this resin composition is not necessarily clear, but (1) the reaction rate between the epoxy group of the epoxy resin and the amino group of the aromatic diamine is probably Appropriate fluidity can be obtained by being appropriate, and (2) after the molten resin composition is cured, the epoxy resin-aromatic diamine cross-linked structure and the rigid aromatic ring skeleton of the aromatic diamine itself. It is presumed that the glass transition temperature is increased due to the above (the thermal motion of molecules in the cured product is limited).
Note that the present invention is not limited by this estimation.

  The component which the resin composition of this embodiment can contain is demonstrated.

(Epoxy resin)
The resin composition of this embodiment contains an epoxy resin.
The epoxy resin may be any as long as it contains an epoxy group. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetramethylbisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol M type epoxy resin, and bisphenol P type epoxy resin. Bisphenol type epoxy resin such as bisphenol Z type epoxy resin; novolak type epoxy resin such as phenol novolak type epoxy resin and cresol novolak type epoxy resin; biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, arylalkylene type epoxy resin, naphthalene type Epoxy resin, anthracene type epoxy resin, phenoxy type epoxy resin, dicyclopentadiene type epoxy resin, norbornene type epoxy resin , It may be mentioned adamantane type epoxy resins, fluorene type epoxy resin, epoxy resins such as tris methane epoxy resin.
The epoxy resin may be semi-cured (solid) at room temperature (25 ° C.).

  In particular, the epoxy resin preferably contains at least one selected from the group consisting of an epoxy resin containing a trisphenylmethane structure and an epoxy resin containing a biphenyl structure. It is thought that the appropriate rigidity of the structure of these epoxy resins facilitates the curing behavior to be more appropriate, and as a result, the moldability can be further improved.

The structure of the above epoxy resin will be supplemented just in case.
Specifically, the epoxy resin containing a trisphenylmethane structure is an epoxy resin containing a partial structure in which three of the four hydrogen atoms of methane (CH ₄ ) are substituted with a benzene ring. Here, the benzene ring may be unsubstituted or substituted with a substituent. Examples of the substituent include a hydroxy group and a glycidyloxy group.
Specifically, the epoxy resin containing a trisphenylmethane structure has a structural unit represented by the following general formula (a1). A trisphenylmethane skeleton is formed by connecting two or more of these structural units.

In general formula (a1):
R ¹¹ is each independently a monovalent organic group, a halogen atom, a hydroxy group or a cyano group when there are a plurality of R ^{11 s} .
When there are a plurality of R ^{12 s} , each independently represents a monovalent organic group, a halogen atom, a hydroxy group or a cyano group;
i is an integer of 0 to 3,
j is an integer of 0-4.

Examples of monovalent organic groups of R ¹¹ and R ¹² include those listed as monovalent organic groups of R ¹ , R ² and R ³ in the general formula (AM) described later.
i and j are each independently preferably 0 to 2, more preferably 0 to 1.
In one aspect, i and j are both 0. That is, as one aspect, all of the benzene rings in the general formula (a1) do not have any substituent other than the explicitly specified glycidyloxy group as the monovalent substituent.

The epoxy resin containing a biphenyl structure is specifically an epoxy resin containing a structure in which two benzene rings are connected by a single bond. The benzene ring here may or may not have a substituent.
Specifically, the epoxy resin containing a biphenyl structure has a partial structure represented by the following general formula (BP).

In general formula (BP):
R ^a and R ^b are each independently a monovalent organic group, a hydroxyl group or a halogen atom when there are a plurality of R ^a and R ^b ,
r and s are each independently 0 to 4,
* Indicates that it is connected to another atomic group.

Specific examples of the monovalent organic groups represented by R ^a and R ^b include those listed as the monovalent organic groups represented by R ¹ , R ² and R ³ in the general formula (AM) described later. .
r and s are each independently preferably 0 to 2, more preferably 0 to 1. In one embodiment, both r and s are 0.

  More specifically, the epoxy resin containing a biphenyl structure has a structural unit represented by the following general formula (BP1).

In general formula (BP1),
The definitions and specific embodiments of R ^a and R ^b are the same as in the general formula (BP),
The definition and preferred range of r and s are the same as in the general formula (BP),
When there are a plurality of R ^{c s} , each is independently a monovalent organic group, a hydroxyl group or a halogen atom;
t is an integer of 0-3.

Specific examples of the monovalent organic group for R ^c include those listed as monovalent organic groups for R ¹ , R ² and R ³ in the general formula (AM) described later.
t is preferably 0 to 2, more preferably 0 to 1.

  Although the molecular weight (number average molecular weight) of an epoxy resin is not specifically limited, For example, it is about 100-3,000, Preferably it is 100-2,000, More preferably, it is about 100-1,000.

The resin composition of this embodiment may contain only 1 type of epoxy resin, and may contain 2 or more types. Moreover, even if it is the same kind of epoxy resin, you may use the thing of a different weight average molecular weight together.
The amount of the epoxy resin in the resin composition is, for example, 0.1 to 20% by mass, preferably 0.5 to 10% by mass, based on the entire resin composition.
Moreover, content of an epoxy resin is 1-30 volume% with respect to the whole resin composition, for example, Preferably it is 5-25 volume%.

(Aromatic diamine)
The resin composition of this embodiment contains an aromatic diamine.
The aromatic diamine can be used without particular limitation as long as it is a compound having one or more aromatic ring structures and two amino groups (—NH ₂ ) in one molecule. The aromatic diamine preferably has a structure in which an amino group is directly bonded to an aromatic ring.

In selecting an aromatic diamine, the melting point can be used as one reference. By using an aromatic diamine having an appropriate melting point, the aromatic diamine is appropriately melted during kneading / molding of the resin composition. Thereby, fluidity | liquidity can be made more favorable. Further, since the resin composition can be kneaded more uniformly, it is considered that the heat resistance and mechanical properties (strength, etc.) of the finally obtained cured product (magnetic member) can be improved.
Specifically, the melting point of the aromatic diamine is preferably 160 ° C. or lower, more preferably 150 ° C. or lower, and further preferably 140 ° C. or lower.
The lower limit of the melting point of the aromatic diamine is not particularly limited, but is, for example, 60 ° C. or higher, preferably 70 ° C. or higher, more preferably 80 ° C. or higher.
In addition, when using a commercial item as aromatic diamine, a catalog value can be employ | adopted about melting | fusing point.

Incidentally, the aromatic diamine is preferably solid at room temperature (25 ° C.) and not liquid. Moreover, although the resin composition of this embodiment may contain amine compounds other than aromatic diamine, the amine compound is also solid at normal temperature (25 degreeC), and it is preferable that it is not liquid.
The resin composition of the present embodiment is typically prepared in a granular or tablet shape. Aromatic diamines (and in some cases amine compounds other than aromatic diamines) are solid at room temperature from the standpoint of ease of preparation and handleability of granular or tablet-like resin compositions obtained by the preparation. It is preferable that

  It is preferable that a resin composition contains the compound represented with the following general formula (AM) as aromatic diamine.

In general formula (AM):
X is each independently selected from the group consisting of a single bond, a linear or branched alkylene group, an ether group, a carbonyl group, an ester group, and a group in which two or more of these are linked, when there are a plurality of X Is the basis of
Y is any group selected from the group consisting of a single bond, a linear or branched alkylene group, an ether group, a carbonyl group, an ester group, and a group in which two or more of these are linked;
R ¹ , R ² and R ³ are each independently a monovalent organic group, a hydroxyl group or a halogen atom when a plurality of R ¹ , R ² and R ³ are present,
k, l and m are each independently an integer of 0 to 4;
n is an integer of 0 or more.

As a linear or branched alkylene group of X and Y, a C1-C6 thing is preferable and a C1-C3 thing is more preferable.
In addition, when some or all of X and Y are branched alkylene groups, the skeleton of the aromatic diamine can be made reasonably rigid. This is considered to be related to making the above-mentioned “melting point” appropriate. Moreover, it is thought that effects, such as the further improvement of the heat resistance of hardened | cured material (magnetic member) and the improvement of mechanical strength, are acquired because the skeleton of aromatic diamine is moderately rigid.

Examples of monovalent organic groups represented by R ¹ , R ² and R ³ include alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, cycloalkyl groups, alkoxy groups, heterocyclic groups, carboxyl groups. Examples include groups.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, An octyl group, a nonyl group, a decyl group, etc. are mentioned.
Examples of the alkenyl group include allyl group, pentenyl group, and vinyl group.
Examples of the alkynyl group include an ethynyl group.
Examples of the alkylidene group include a methylidene group and an ethylidene group.
Examples of the aryl group include a tolyl group, a xylyl group, a phenyl group, a naphthyl group, and an anthracenyl group.
Examples of the aralkyl group include a benzyl group and a phenethyl group.
Examples of the alkaryl group include a tolyl group and a xylyl group.
Examples of the cycloalkyl group include an adamantyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.
Examples of the alkoxy group include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, s-butoxy group, isobutoxy group, t-butoxy group, n-pentyloxy group, and neopentyloxy group. , N-hexyloxy group and the like.
Examples of the heterocyclic group include an epoxy group and an oxetanyl group.
The total carbon number of the monovalent organic group of R ¹ , R ² and R ³ is, for example, 1 to 30, preferably 1 to 20, more preferably 1 to 10, particularly preferably 1 to 6, respectively.

k, l and m are each independently preferably an integer of 0 or 1.
In one embodiment, k, l and m are all 0. That is, as one embodiment, all of the benzene rings in the general formula (AM) are not substituted with an atomic group other than an amino group.
n is preferably 0 to 3, more preferably 0 to 2.

  Specific examples of the aromatic diamine are shown below. In addition, aromatic diamine is not limited only to the following. Of course, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene, 2,2′-bis [4- (4-aminophenoxy) used in the examples described later. ) Phenyl] propane, 1,3-bis (4-aminophenoxy) benzene, and the like.

  About aromatic diamine, you may use a commercial item. The aromatic diamine can be obtained from, for example, Seika Co., Ltd., Mitsui Chemicals Fine Co., Ltd., Fuji Film Wako Pure Chemical Industries, Ltd.

The resin composition of this embodiment may contain only 1 type of aromatic diamine, and may contain 2 or more types.
The amount of the aromatic diamine in the resin composition is, for example, 0.1 to 20% by mass, preferably 0.5 to 10% by mass, based on the entire resin composition.
The amount of aromatic diamine in the resin composition is, for example, 1 to 30% by volume, preferably 5 to 25% by volume, based on the entire resin composition. By setting it as such a numerical range, a moldability and a mechanical characteristic can be improved.

In addition, it is preferable that the quantity of aromatic diamine in a composition is adjusted suitably in relation to an epoxy resin.
Specifically, the ratio of the number of moles of epoxy groups possessed by the epoxy resin to the number of moles of amino groups possessed by the aromatic diamine (that is, the number of moles of epoxy groups possessed by the epoxy resin / the mole of amino groups possessed by the aromatic diamine). The number) is preferably 1 to 3, more preferably 1.5 to 2.5, and still more preferably 1.7 to 2.3.
One amino group (—NH ₂ ) can react with two epoxy groups. Therefore, it is considered that the cross-linked structure of the amino group and the epoxy group at the time of curing can be made denser by adjusting the amount ratio of the epoxy resin and the aromatic diamine so that the above ratio is about 2. And it is thought that the glass transition temperature of hardened | cured material (magnetic member) can be raised and heat resistance can be improved.
The above ratio is calculated from the epoxy equivalent or epoxy value of the epoxy resin contained in the composition, the molecular weight of the epoxy resin (these are usually shown in the epoxy resin catalog), the molecular weight of the aromatic diamine, and the like. Can be obtained.

(Magnetic particles)
The resin composition of the present embodiment includes magnetic particles.
Any magnetic particles can be used as long as the molded product produced using the resin composition of the present embodiment exhibits magnetism.

The magnetic particles preferably contain one or more elements selected from the group consisting of Fe, Cr, Co, Ni, Ag and Mn. By selecting one of these magnetic particles, the magnetic properties can be further enhanced.
In particular, the magnetic properties can be further enhanced by using magnetic particles containing 85 mass% or more of Fe.

  The magnetic particles may be a crystalline material, an amorphous material, or a material in which these are mixed. Moreover, as a magnetic particle, what consists of 1 type of chemical composition may be used, and 2 or more types of different chemical compositions may be used together.

In particular, as the magnetic particles, those containing iron-based particles are preferable. Note that the iron-based particles are particles containing iron atoms as a main component (the largest mass of iron atoms in the chemical composition), and more specifically, the content of iron atoms in the chemical composition is the same. This is the most common iron alloy.
More specifically, particles (soft magnetic iron high content particles) that exhibit soft magnetism and have an iron atom content of 85% by mass or more can be used as the iron-based particles. Soft magnetism refers to ferromagnetism with a small coercive force, and in general, ferromagnetism with a coercive force of 800 A / m or less is referred to as soft magnetism.

  Examples of the constituent material of such particles include a metal-containing material having a content of iron as a constituent element of 85% by mass or more. Thus, a metal material having a high content of iron as a constituent element exhibits soft magnetism with relatively good magnetic properties such as magnetic permeability and magnetic flux density. For this reason, when it shape | molds, the resin composition which can show a favorable magnetic characteristic is obtained.

  Examples of the form of the metal-containing material include simple solutions, alloys such as solid solutions, eutectics, and intermetallic compounds. By using particles composed of such a metal material, a resin composition having excellent magnetic properties derived from iron, that is, magnetic properties such as high permeability and high magnetic flux density can be obtained.

  Moreover, said metal containing material may contain elements other than iron as a structural element. Examples of elements other than iron include B, C, N, O, Al, Si, P, S, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, and Cd. , In, Sn and the like, and one or more of these may be used in combination.

  Specific examples of the metal-containing material include, for example, pure iron, silicon steel, iron-cobalt alloy, iron-nickel alloy, iron-chromium alloy, iron-aluminum alloy, carbonyl iron, stainless steel, or of these Examples thereof include composite materials containing one kind or two or more kinds. Carbonyl iron can be preferably used from the viewpoint of availability.

  In the above description, iron-based particles have been mainly described. Of course, the magnetic particles may be other particles. For example, magnetic particles including Ni-based soft magnetic particles, Co-based soft magnetic particles, and the like may be used.

Further, the magnetic particles may be subjected to a surface treatment. For example, the surface may be treated with a coupling agent or may be plasma treated. By such a surface treatment, it is possible to bond a functional group to the surface of the magnetic particles. The functional group can cover a part or the entire surface of these particles.
As such a functional group, a functional group represented by the following general formula (1) can be used.
* -O-X-R (1)
[Wherein, R represents an organic group, X represents Si, Ti, Al, or Zr, and * represents one of the atoms constituting the magnetic particles. ]

  The functional group is, for example, a residue formed by surface treatment with a known coupling agent such as a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, or a zirconium coupling agent. It is preferably a residue of a coupling agent selected from the group consisting of silane coupling agents and titanium coupling agents. Thereby, when a magnetic body particle | grain is mix | blended with a resin composition and it is set as a resin composition, the fluidity | liquidity can be improved more.

When the surface treatment is performed with a coupling agent, examples of the method include a method of immersing magnetic particles in a diluted solution of the coupling agent or spraying the coupling agent directly on the magnetic particles.
The amount of the coupling agent used is, for example, preferably 0.05 to 1 part by mass and more preferably 0.1 to 0.5 part by mass with respect to 100 parts by mass of the magnetic particles.
Examples of the solvent for reacting the coupling agent with the magnetic particles include methanol, ethanol, isopropyl alcohol, and the like. Moreover, it is preferable that it is 0.1-2 mass parts with respect to 100 mass parts of solvents, and, as for the usage-amount of the coupling agent at this time, it is more preferable that it is 0.5-1.5 mass parts.
The reaction time between the coupling agent and the magnetic particles (for example, the immersion time in the diluted solution) is preferably 1 to 24 hours.

  In addition, when the functional groups as described above are bonded, plasma treatment may be performed in advance as part of the surface treatment for the magnetic particles. For example, by performing oxygen plasma treatment, OH groups are generated on the surface of the magnetic particles, and the bonding between the magnetic particles and the residue of the coupling agent via oxygen atoms becomes easy. Thereby, a functional group can be combined more firmly.

The plasma treatment here is preferably oxygen plasma treatment. Thereby, the OH group can be efficiently modified on the surface of the magnetic particles.
Although the pressure of oxygen plasma processing is not specifically limited, It is preferable that it is 100-200 Pa, and it is more preferable that it is 120-180 Pa.
The flow rate of the processing gas in the oxygen plasma processing is not particularly limited, but is preferably 1000 to 5000 mL / min, and more preferably 2000 to 4000 mL / min.
The output of the oxygen plasma treatment is not particularly limited, but is preferably 100 to 500 W, and more preferably 200 to 400 W.
The treatment time of the oxygen plasma treatment is appropriately set according to the various conditions described above, but is preferably 5 to 60 minutes, and more preferably 10 to 40 minutes.

  Further, an argon plasma treatment may be further performed before the oxygen plasma treatment. Thereby, since the active point for modifying the OH group can be formed on the surface of the magnetic particle, the modification of the OH group can be performed more efficiently.

Although the pressure of argon plasma processing is not specifically limited, It is preferable that it is 10-100 Pa, and it is more preferable that it is 15-80 Pa.
The flow rate of the processing gas in the argon plasma processing is not particularly limited, but is preferably 10 to 100 mL / min, and more preferably 20 to 80 mL / min.
The output of the argon plasma treatment is preferably 100 to 500 W, and more preferably 200 to 400 W.
The treatment time for the argon plasma treatment is preferably 5 to 60 minutes, and more preferably 10 to 40 minutes.

In addition, it can confirm that a magnetic body particle and the residue of a coupling agent have couple | bonded through an oxygen atom, for example with a Fourier-transform infrared spectrophotometer.
Further, the surface treatment as described above may be applied to all particles contained in the resin composition, or may be applied only to some of the particles.

  Further, another coating treatment may be applied to the surface treatment base described above. Examples of such coating treatment include a phosphoric acid coat, a silica coat, etc. in addition to a resin coat such as a silicone resin. By performing such a coating treatment, the insulating properties of the magnetic particles can be further enhanced. Such a coating process may be performed as necessary and may be omitted. This coating treatment may be performed alone, not as a base for the surface treatment described above.

From another viewpoint, the magnetic particles preferably have a shape close to a perfect circle (true sphere). Thereby, it is thought that friction between particles decreases and fluidity can be further improved.
Specifically, the “roundness” defined below is obtained for any 10 or more (preferably 50 or more) magnetic particles, and the average roundness obtained by averaging the values is It is preferably 0.60 or more, and more preferably 0.75 or more.
Definition of roundness: When the contour of a magnetic particle is observed with a scanning electron microscope, the equivalent area equivalent diameter obtained from the contour is Req, and the radius of a circle circumscribing the contour is Rc. The value of Req / Rc.

From the viewpoint of good fluidity and improvement in magnetic performance due to high filling, the particle size of the magnetic particles is preferably adjusted as appropriate.
For example, the median diameter D _{50 on} the volume basis of the magnetic particles is preferably 0.5 to 75 μm, more preferably 0.75 to 65 μm, and further preferably 1 to 60 μm. By appropriately adjusting the particle size (median diameter), it is possible to further improve the fluidity during molding or improve the magnetic performance.

Incidentally, the median diameter D ₅₀ is, for example, can be obtained by laser diffraction / scattering particle size distribution analyzer. Specifically, a particle size distribution curve is obtained by measuring magnetic particles by a dry method using a particle size distribution measuring apparatus “LA-950” manufactured by HORIBA, and D ₅₀ is obtained by analyzing the distribution curve. be able to.

The content of the magnetic particles in the resin composition is preferably 90% by mass or more, more preferably 93% by mass or more, and still more preferably 95% by mass or more, based on the entire resin composition. The upper limit of the content of the magnetic particles in the resin composition is, for example, 99% by mass or less from the viewpoint of practically securing the fluidity of the resin composition. By sufficiently increasing the content of the magnetic particles, the magnetic performance (such as magnetic permeability and iron loss) can be further improved.
Further, on the volume basis, the content of the magnetic particles in the resin composition is preferably 60% by volume or more, more preferably 70% by volume or more, and further preferably 80% by volume or more, based on the whole resin composition. is there. About the upper limit of this, it is 95 volume% or less from the point etc. which ensure the fluidity | liquidity of a resin composition realistically, etc.

  The resin composition of this embodiment may contain arbitrary components other than an epoxy resin, aromatic diamine, and a magnetic particle. Hereinafter, arbitrary components will be described.

(Release agent)
The resin composition of this embodiment may contain a mold release agent. Thereby, the mold release property of the resin composition at the time of shaping | molding can be improved.
Examples of the mold release agent include natural waxes such as carnauba wax, synthetic waxes such as montanic acid ester wax and oxidized polyethylene wax, higher fatty acids such as zinc stearate and metal salts thereof, and paraffin. These may be used alone or in combination of two or more.

  When using a mold release agent, the content is preferably 0.01 to 3 mass%, more preferably 0.05 to 2 mass%, based on the entire resin composition. Thereby, the effect of mold release improvement can be acquired reliably.

(Non-magnetic particles)
The resin composition of the present embodiment may include nonmagnetic particles exhibiting nonmagnetic properties from the viewpoint of adjusting fluidity. As the non-magnetic particles, for example, particles having a cumulative 50% value (D ₅₀ ) in a particle size distribution curve of 3 μm or less can be used. In this specification, non-magnetic means having no ferromagnetism.

  When the resin composition contains non-magnetic particles, the fluidity is higher when molding and the bleeding of the resin composition during molding is suppressed. For this reason, the moldability of the resin composition becomes better, and the filling properties and uniformity of the magnetic particles can be further improved. Accordingly, the magnetic properties of the cured product (magnetic member) can be improved.

  Moreover, the occurrence of resin burrs or the like during molding is suppressed by suppressing the seepage of the resin composition. In addition, it can be prevented that the component balance of the resin composition is lost due to the oozing and the mechanical properties of the molded body are deteriorated. Therefore, a molded body with few molding defects is obtained.

  Examples of the constituent material of the non-magnetic particles include a ceramic material and a glass material. Of these, those containing a ceramic material are preferably used. Since such non-magnetic particles have high affinity with the thermosetting resin, the fluidity of the resin composition can be maintained.

Examples of the ceramic material include oxide ceramic materials such as silica, alumina, zirconia, titania, magnesia, and calcia, nitride ceramic materials such as silicon nitride and aluminum nitride, and carbide materials such as silicon carbide and boron carbide. A ceramic material etc. are mentioned.
The ceramic material particularly preferably contains silica. Silica is useful as a constituent particle of non-magnetic particles because of its high affinity with thermosetting resins and high insulating properties.

  The true specific gravity of the constituent material of the non-magnetic particles is preferably 1.0 to 6.0, more preferably 1.2 to 5.0, and more preferably 1.5 to 4.5. Further preferred. Since such nonmagnetic particles have a small specific gravity, they tend to flow together with the melt of the resin composition. For this reason, when the melt of the resin composition flows toward the gap or the like of the mold during molding, the nonmagnetic particles easily flow along with the melt. As a result, the gap is blocked by the nonmagnetic particles, and the seepage from the gap can be more reliably suppressed. The “gap” herein includes, for example, a gap (clearance) between a plunger and a cylinder of a transfer molding machine.

  The cumulative 50% value of the non-magnetic particles in the volume-based particle size distribution curve is not particularly limited, but is typically 3 μm or less, preferably 0.1 to 2.8 μm, more preferably 0. .5 to 2.5 μm. This particle size is a preferable particle size for preventing the above-mentioned “bleeding out”, and is a particle size that easily flows together with the melt of the resin composition.

Further, the cumulative 50% value of the non-magnetic particles in the volume-based particle size distribution curve is preferably 3 μm or less and smaller than D _{50 of the} magnetic particles, but the difference is more preferably 5 μm or more. 10 to 100 μm is more preferable, and 15 to 60 μm is particularly preferable.

  The average roundness of the nonmagnetic particles contained in the nonmagnetic particles (this definition is the same as that in the magnetic particles) is not particularly limited, but is preferably 0.50 to 1, More preferably, it is .75-1. When the roundness is within this range, the fluidity of the resin composition can be secured by utilizing the rolling of the nonmagnetic particles themselves, while the nonmagnetic particles are easily clogged in gaps and the like. It becomes easy to suppress exudation. That is, the fluidity of the resin composition and the suppression of the seepage of the thermosetting resin can be made compatible.

  When non-magnetic particles are used, the amount thereof is preferably 1 to 10% by mass, more preferably 2 to 5% by mass based on the entire resin composition. Thereby, the fluidity | liquidity is higher and the resin composition which can suppress a bleed-out more reliably is obtained.

(Resin different from epoxy resin)
The resin composition of the present embodiment may contain a resin different from the epoxy resin from the viewpoint of adjusting fluidity and moldability.
Examples of the resin different from the epoxy resin include a thermosetting resin that is not an epoxy resin, and a thermoplastic resin.

  Thermosetting resins that are not epoxy resins include phenolic resins, polyimide resins, bismaleimide resins, urea (urea) resins, melamine resins, polyurethane resins, cyanate ester resins, silicone resins, oxetane resins (oxetane compounds), (meth). Examples include acrylate resins, unsaturated polyester resins, diallyl phthalate resins, and benzoxazine resins.

  Examples of the thermoplastic resin include acrylic resins, polyamide resins (for example, nylon), thermoplastic urethane resins, polyolefin resins (for example, polyethylene and polypropylene), polycarbonate, polyester resins (for example, polyethylene terephthalate, polybutylene). Terephthalate, etc.), polyacetal, polyphenylene sulfide, polyether ether ketone, liquid crystal polymer, fluororesin (eg, polytetrafluoroethylene, polyvinylidene fluoride, etc.), modified polyphenylene ether, polysulfone, polyethersulfone, polyarylate, polyamideimide, poly Examples include ether imide and thermoplastic polyimide.

When using a resin different from the epoxy resin, one type may be used alone, or two or more different types may be used in combination. Moreover, even if it is the same kind of resin, you may use together 2 or more types of a different weight average molecular weight. Further, a certain resin and its prepolymer may be used in combination.
When using a resin different from the epoxy resin, the amount thereof is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass based on the entire resin composition. Thereby, it is thought that the adjustment effect of fluidity | liquidity and a moldability is fully acquired.

(Other ingredients)
The resin composition of this embodiment may contain components other than the components described above. For example, the resin composition of the present embodiment may contain a low stress agent, a coupling agent, an adhesion aid, a colorant, an antioxidant, a corrosion inhibitor, a dye, a pigment, a flame retardant, and the like.

  Examples of the low stress agent include silicone compounds such as polybutadiene compounds, acrylonitrile butadiene copolymer compounds, silicone oils, and silicone rubbers. When using a low stress agent, only 1 type may be used and 2 or more types may be used together.

  As the coupling agent, the above-described coupling agent used for the surface treatment of magnetic particles can be used. For example, a silane coupling agent, a titanium coupling agent, a zirconia coupling agent, an aluminum coupling agent, and the like can be given. When using a coupling agent, only 1 type may be used and 2 or more types may be used together.

When a resin composition contains another component, the quantity is suitably adjusted in the range of 0.001-10 mass%, for example on the basis of the whole resin composition.
In addition, it is preferable that the resin composition of this embodiment does not contain an epoxy curing catalyst (curing catalyst of the above-mentioned epoxy resin) substantially. Since the resin composition does not substantially contain an epoxy curing catalyst, the fluidity can be particularly improved.
Here, “substantially free” means, for example, 0.1% by mass or less, based on the entire resin composition.
The resin composition of this embodiment ideally does not contain an epoxy curing catalyst.

Examples of the epoxy curing catalyst include organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt (II), and trisacetylacetonate cobalt (III). Tertiary amines such as triethylamine, tributylamine, 1,4-diazabicyclo [2.2.2] octane; 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 2,4-diethylimidazole Imidazoles such as 2-phenyl-4-methyl-5-hydroxyimidazole and 2-phenyl-4,5-dihydroxymethylimidazole; triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium tetraphenylborate, triphenyl Phenyl Sufin Triphenyl borane, 1,2-bis - organophosphorus compounds such as (diphenylphosphino) ethane; acetic, benzoic acid, salicylic acid, and organic acids such as p- toluenesulfonic acid.
As a precaution, the epoxy curing catalyst is a compound that has a function of promoting a curing reaction (crosslinking structure forming reaction) between an epoxy resin and a curing agent. Usually, the epoxy curing catalyst itself does not form a covalent bond with the epoxy resin.

(Properties of resin composition, etc.)
The resin composition of this embodiment may be solid at room temperature 25 ° C.
The properties of the resin composition of the present embodiment can be a powder, granules, tablets, or the like.
In the resin composition of the present embodiment, for example, first, (1) an epoxy resin, an aromatic diamine, and magnetic particles (optionally further optional components) are mixed using a mixer. It can be produced by kneading at about 120 ° C. for about 5 minutes to obtain a kneaded product, (3) and cooling the obtained kneaded product after cooling. (By the above, a powdery resin composition can be obtained.)
In addition, if necessary, the powdery resin composition may be compressed into granules or tablets. Thereby, a resin composition suitable for resin molding such as transfer molding can be obtained. Further, by making the resin composition solid at room temperature (25 ° C.), it is possible to improve transportability and storage property.

<Manufacturing method of molded product>
The resin composition of the present embodiment can be molded into a desired shape by various molding methods such as transfer molding, injection molding, extrusion molding, and press molding.
Among these methods, the resin composition of the present embodiment is suitable for molding by a transfer molding method. That is, a transfer member can be used to inject a melt of the resin composition described above into a mold and obtain a magnetic member in which the melt is cured. The molded product can be suitably used as a magnetic component in an electric / electronic device. More specifically, the molded product is suitably used as a magnetic core of a coil (also called a reactor or an inductor depending on applications and purposes).

The transfer molding can be performed by appropriately using a known transfer molding apparatus. Specifically, first, the preheated resin composition is put in a heating chamber called a transfer chamber and melted to obtain a melt. Thereafter, the melt is poured into a mold with a plunger and held as it is to cure the melt. Thereby, a desired molded product can be obtained.
Transfer molding is preferable to other molding methods in terms of controllability of the dimension of the molded product and improvement in the degree of freedom of shape.

  Various conditions in transfer molding can be arbitrarily set. For example, the preheating temperature is 60 to 100 ° C., the heating temperature at the time of melting is 150 to 250 ° C., the mold temperature is 150 to 200 ° C., and the pressure when pouring the melt of the resin composition into the mold is 1 to It can adjust suitably between 20 Mpa.

<Magnetic member and coil>
A magnetic member (magnetic member formed by curing the resin composition of the present embodiment) formed of the resin composition of the present embodiment, and a mode of a coil including the magnetic member as a magnetic core or an exterior member will be described. .

(First aspect)
Fig.1 (a) and FIG.1 (b) are the figures which showed typically the coil 100 (reactor) provided with the magnetic core comprised with the hardened | cured material of the resin composition of this embodiment.
Fig.1 (a) shows the outline | summary of the coil 100 seen from the upper surface. FIG.1 (b) shows sectional drawing in the AA 'cross section view in Fig.1 (a).

As shown in FIG. 1, the coil 100 can include a winding 10 and a magnetic core 20. The magnetic core 20 is filled in a winding 10 that is an air-core coil. The pair of windings 10 shown in FIG. 1A are connected in parallel. In this case, the annular magnetic core 20 has a structure penetrating the inside of the pair of windings 10 shown in FIG. The magnetic core 20 and the winding 10 can have an integrated structure.
Note that the coil 100 may have a structure in which an insulator (not shown) is interposed between the winding 10 and the magnetic core 20 from the viewpoint of securing these insulations.

  In the coil 100, the winding 10 and the magnetic core 20 may be sealed with an exterior member 30 (sealing member). For example, the winding 10 and the magnetic core 20 are accommodated in a casing (case), a liquid resin is introduced into the casing 10, and the liquid resin is cured as necessary. The exterior member 30 may be formed. At this time, the winding 10 may have a drawing portion (not shown) in which the end of the winding is drawn to the outside of the exterior member 30.

  The winding 10 is usually configured by winding a winding having a metal wire surface with an insulating coating. The metal wire is preferably highly conductive, and copper and copper alloys can be suitably used. The insulating coating can be a coating such as enamel. Examples of the cross-sectional shape of the winding include a circle, a rectangle, and a hexagon.

  On the other hand, the cross-sectional shape of the magnetic core 20 is not particularly limited. For example, the cross-sectional shape may be a circular shape or a polygonal shape such as a quadrangle or a hexagon. Since the magnetic core 20 is constituted by, for example, a transfer molded product of the resin composition of the present embodiment, it can have a desired shape.

  According to the cured product of the resin composition of the present embodiment, the magnetic core 20 excellent in moldability and magnetic properties can be realized. That is, the coil 100 including the magnetic core 20 is expected to be suitable for mass production and have a small iron loss. In addition, since the magnetic core 20 having excellent mechanical characteristics can be realized, the durability, reliability, and manufacturing stability of the coil 100 can be improved. For this reason, the coil 100 can be used as a reactor for a booster circuit or a large current.

(Second aspect)
As an aspect different from the above-described coil, an outline of a coil (inductor) including an exterior member made of a cured product of the resin composition of the present embodiment will be described with reference to FIG.
FIG. 2A shows an outline of the coil viewed from the upper surface of the coil 100B. FIG. 2B is a cross-sectional view taken along the line BB ′ in FIG.

As shown in FIG. 2, the coil 100B can include a winding 10B and a magnetic core 20B. The magnetic core 20B is filled in a winding 10B that is an air-core coil. The pair of windings 10B illustrated in FIG. 2A are connected in parallel. In this case, the annular magnetic core 20B has a structure penetrating the inside of the pair of windings 10B shown in FIG. These magnetic cores 20B and windings 10B can be individually created and combined to have a combined structure.
The coil 100B may have a structure in which an insulator (not shown) is interposed between the winding 10B and the magnetic core 20B from the viewpoint of securing these insulations.

  In the coil 100B, the winding 10B and the magnetic core 20B are sealed with an exterior member 30B (sealing member). For example, the magnetic core 20B filled in the winding 10B is placed in a mold, and by using the resin composition of this embodiment, the resin composition is cured by molding such as transfer molding, An exterior member 30B can be formed around the winding 10B and the magnetic core 20B. At this time, the winding 10B may have a drawing portion (not shown) in which the end of the winding is drawn to the outside of the exterior member 30B.

  The winding 10 </ b> B is usually configured by a structure in which a conductive wire having an insulating coating on the surface of a metal wire is wound. The metal wire is preferably highly conductive, and copper and copper alloys can be suitably used. The insulating coating can be a coating such as enamel. Examples of the cross-sectional shape of the winding 10B include a circle, a rectangle, and a hexagon.

  On the other hand, the cross-sectional shape of the magnetic core 20B is not particularly limited. For example, it can be a circular shape or a polygonal shape such as a quadrangle or a hexagon in a cross-sectional view. As the magnetic core 20B, for example, a dust core made of magnetic powder and a binder can be used.

  According to the cured product of the resin composition of the present embodiment, since the exterior member 30B having excellent moldability and magnetic properties can be realized, a low magnetic loss is expected in the coil 100B including the magnetic core 20B. In addition, since the exterior member 30B having excellent mechanical characteristics can be realized, the durability, reliability, and manufacturing stability of the coil 100B can be improved.

(Third aspect)
As another aspect, an outline of an integrated inductor including a magnetic core and an exterior member made of a cured product of the resin composition of the present embodiment will be described with reference to FIG.
FIG. 3A shows an outline of the structure viewed from the upper surface of the integrated inductor 100C. FIG. 3B is a cross-sectional view taken along the line CC ′ in FIG.

  As shown in FIG. 3, the integrated inductor 100 </ b> C can include a winding 10 </ b> C and a magnetic core 20 </ b> C. The magnetic core 20C is filled in the inside of the winding 10 that is an air-core coil. Winding 10C and magnetic core 20C are sealed with exterior member 30C (sealing member). The magnetic core 20C and the exterior member 30C can be made of a cured product of the resin composition of the present embodiment. The magnetic core 20C and the exterior member 30C may be formed as a seamless integral member.

  As a manufacturing method of the integrated inductor 100C, for example, the winding 10C is disposed in a mold, and a mold such as transfer molding is performed using the resin composition of the present embodiment. Thereby, the resin composition is cured, and the magnetic core 20C filled in the winding 10C and the exterior member 30C can be integrally formed around these. At this time, the winding 10 </ b> C may have a lead portion (not shown) in which an end portion of the winding is pulled out of the exterior member 30 </ b> C.

  The winding 10 </ b> C is usually configured by winding a conductive wire with an insulating coating on the surface of a metal wire. The metal wire is preferably highly conductive, and copper and copper alloys can be suitably used. The insulating coating can be a coating such as enamel. Examples of the cross-sectional shape of the winding 10C include a circle, a rectangle, and a hexagon.

  On the other hand, the cross-sectional shape of the magnetic core 20 </ b> C is not particularly limited, but can be, for example, a circular shape or a polygonal shape such as a quadrangle or a hexagon when viewed in cross-section. Since the magnetic core 20 </ b> C is configured by a transfer molded product of the resin composition of the present embodiment, it can have a desired shape.

  According to the cured product of the resin composition of the present embodiment, the magnetic core 20C and the exterior member 30C having excellent moldability and magnetic properties can be realized. Therefore, in the integrated inductor 100C having these, low magnetic loss is expected. The In addition, since the exterior member 30C having excellent mechanical characteristics can be realized, it is possible to improve durability, reliability, and manufacturing stability of the integrated inductor 100C. For this reason, the integrated inductor 100C can be used as an inductor for a booster circuit or a large current.

(Supplementary information on magnetic members)
As described above, the magnetic member of the present embodiment (cured product of the resin composition of the present embodiment) has good heat resistance. Specifically, the glass transition temperature measured using a thermomechanical analyzer under conditions of a measurement temperature range of 0 ° C. to 400 ° C. and a heating rate of 5 ° C./min is preferably 175 ° C. or more, more preferably 200-300 ° C.

Further, the magnetic member of the present embodiment tends to have a relatively small coefficient of thermal expansion. About this, it is estimated that the crosslinked structure of an epoxy resin-aromatic diamine is relatively dense and the rigid aromatic ring skeleton of the aromatic diamine itself is related.
The property that the coefficient of thermal expansion is relatively small is preferable in terms of dimensional control of the magnetic member.
Specifically, the average linear expansion coefficient at 270 to 290 ° C. measured under conditions of a measurement temperature range of 0 ° C. to 400 ° C. and a heating rate of 5 ° C./min using a thermomechanical analyzer is preferably 5-60 ppm / ° C, more preferably 20-40 ppm / ° C.

Furthermore, the magnetic member of the present embodiment tends to have relatively good mechanical properties (physical strength). Also about this, it is estimated that the epoxy resin-aromatic diamine cross-linking structure is relatively dense and the rigid aromatic ring skeleton of the aromatic diamine itself is related.
Specifically, the bending strength measured according to JIS K 6911 is preferably 100 MPa or more, more preferably 130 MPa or more.

<Resin composition used for forming magnetic member by mixing with magnetic particles>
In the above, the embodiment of the resin composition containing the three components “epoxy resin, aromatic diamine, and magnetic particles” and the magnetic member (cured product) obtained using the resin composition has been described.

On the other hand, as another embodiment, (1) First, a resin composition containing two components of “epoxy resin and aromatic diamine” (not including magnetic particles) is prepared, and then (2) The resin composition is mixed with magnetic particles to obtain a mixture. (3) Then, the mixture is melted, poured into a mold, and molded to obtain a magnetic member (cured product).
Note that the timing of the mixing step (2) can be, for example, immediately before the molding step (3).

The resin composition of the above (1) can also be expressed as a “resin composition used for forming a magnetic member by mixing with magnetic particles” containing an epoxy resin and an aromatic diamine. Specific embodiments of the epoxy resin and aromatic diamine in this resin composition are the same as those described above.
Moreover, the resin composition of said (1) may also contain arbitrary components other than an epoxy resin and aromatic diamine. As an optional component, as described above, a release agent, non-magnetic particles, a resin different from an epoxy resin, a low stress agent, a coupling agent, an adhesion aid, a colorant, an antioxidant, an anticorrosive, a dye, A pigment, a flame retardant, etc. can be mentioned.

In the mixing step (2), for example, the resin composition and the magnetic particles are mixed using a mixer, and then kneaded by using a roll at about 120 ° C. for about 5 minutes. The product can be obtained, and the kneaded product obtained can be cooled and ground.
In addition, about the specific aspect of a magnetic body particle, the quantity of the magnetic body particle in a mixture, etc., in the resin composition containing three components of the above-mentioned "epoxy resin, aromatic diamine, and magnetic body particle" Reference can be made to embodiments.

  Regarding the specific aspect of the molding step (3) above, the description of <Method for producing molded product> can be referred to.

<Kit>
As yet another embodiment, a magnetic member (cured product) can be obtained by a magnetic member molding kit comprising a first component containing an epoxy resin and an aromatic diamine and a second component containing magnetic particles. it can.
In this kit, the first component and the second component are usually not in contact with each other until just before use. For example, the first component and the second component are each contained in separate containers.
The first component usually does not contain magnetic particles. Moreover, a 2nd component does not normally contain an epoxy resin and aromatic diamine.

Specific embodiments of the epoxy resin and aromatic diamine in the first component are the same as those described above.
Specific embodiments of the magnetic particles in the second component are the same as those described above.
The first component and / or the second component may include other optional components. As an optional component, as described above, a release agent, non-magnetic particles, a resin different from an epoxy resin, a low stress agent, a coupling agent, an adhesion aid, a colorant, an antioxidant, an anticorrosive, a dye, A pigment, a flame retardant, etc. can be mentioned.

A magnetic member (cured product) can be obtained by mixing the first component and the second component of the kit to obtain a mixture, and then melting and pouring the mixture into a mold and molding.
For specific methods and embodiments such as mixing, melting, mold injection, etc., the above <resin composition>, <resin composition used to form a magnetic member by mixing with magnetic particles>, <molded product Refer to the description such as “Production method>”.

  As mentioned above, although embodiment of this invention was described, these are illustrations of this invention and can employ | adopt various structures other than the above. Further, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  Embodiments of the present invention will be described in detail based on examples and comparative examples. In addition, this invention is not limited to an Example.

<Preparation of resin composition>
For each of the examples, a resin composition was prepared as follows. First, each component described in Table 1 was prepared in the amount described and mixed using a mixer. Next, the obtained mixture was roll kneaded. Then, it cooled, grind | pulverized, and tableted and formed. The tablet-shaped resin composition was obtained by the above.
The amount of each component listed in Table 1 is parts by mass.
Specifically, the raw material components described in Table 1 are as follows.

(Epoxy resin)
Epoxy resin A: Epoxy resin containing a trisphenylmethane structure (Mitsubishi Chemical Corporation, E1032H60, solid at 25 ° C., having a structural unit represented by the general formula (a1))
Epoxy resin B: Epoxy resin containing a biphenylaralkyl type structure (Nippon Kayaku Co., Ltd., NC3000, solid at 25 ° C., having a structural unit represented by the above general formula (BP1))

(Phenolic curing agent (for comparison))
Phenolic resin A: Novolac type phenolic resin (Sumitomo Bakelite Co., Ltd., PR-HF-3, solid at 25 ° C.)

(Aromatic diamine)
Aromatic diamine A: 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene (Mitsui Chemical Fine Co., Ltd., Bisanline-M, solid at 25 ° C., melting point 114 ° C.)
Aromatic diamine B: 2,2′-bis [4- (4-aminophenoxy) phenyl] propane (Seika Co., Ltd., BAPP, solid at 25 ° C., melting point 128 ° C.)
Aromatic diamine C: 1,3-bis (4-aminophenoxy) benzene (manufactured by Seika Corporation, TPE-R, solid at 25 ° C., melting point 116 ° C.)

(Curing catalyst)
Curing catalyst A: Imidazole-based curing accelerator (manufactured by Shikoku Kasei Kogyo Co., Ltd., Curesol 2PZ-PW)

(Release agent)
Release agent A: Synthetic wax (Clariant Chemicals, Inc., WE-4)

(Magnetic particles)
Magnetic particles A: Amorphous magnetic powder (manufactured by Epson Atmix Co., Ltd., KUAMET6B2, median diameter D ₅₀ : 50 μm, Fe 88% by mass)
Magnetic particles B: Amorphous magnetic powder (manufactured by Epson Atmix Co., Ltd., KUAMET6B2, median diameter D ₅₀ : 25 μm, Fe 88% by mass)
Magnetic particles C: Alloy steel powder (Daido Special Steel Co., Ltd., DAPMSC5, median diameter D ₅₀ : 10 μm, Fe 91 mass%)
Magnetic particles D: Carbonyl iron powder (BASF, CIP-HQ, median diameter D ₅₀ : 2 μm, Fe 99% by mass)

<Performance evaluation>
Each resin composition was evaluated as follows.

(Fluidity: Spiral flow flow length)
Using a low-pressure transfer molding machine (“KTS-15” manufactured by Kotaki Seiki Co., Ltd.), a mold for spiral flow measurement according to EMMI-1-66, mold temperature 175 ° C., injection pressure 6.9 MPa, curing The resin composition was injected under the condition of time 120 seconds, and the flow length was measured.
The larger the flow length, the better the fluidity.

(Heat resistance: Glass transition temperature (Tg))
The resin composition was injection-molded using a low-pressure transfer molding machine (“KTS-30” manufactured by Kotaki Seiki Co., Ltd.) at a mold temperature of 175 ° C., an injection pressure of 9.8 MPa, and a curing time of 120 seconds, 15 mm × 4 mm × A molded product of 4 mm was obtained. Next, the obtained molded product was post-cured at 175 ° C. for 4 hours to prepare a test piece.
With respect to the obtained test piece, the glass transition temperature was measured using a thermomechanical analyzer (manufactured by Seiko Instruments Inc., TMA100) under the conditions of a measurement temperature range of 0 ° C to 400 ° C and a heating rate of 5 ° C / min. Tg (° C.) was measured.
It represents that heat resistance is so favorable that Tg is large.

(Linear expansion coefficient)
From the measurement result by said thermomechanical analyzer, average linear expansion coefficient (alpha) ₁ (ppm / degreeC) in 50-70 degreeC and average linear expansion coefficient (alpha) ₂ (ppm / degreeC) in 270-290 degreeC were measured.

(Relative permeability)
The resin composition was injection-molded using a low-pressure transfer molding machine (“KTS-30” manufactured by Kotaki Seiki Co., Ltd.) at a mold temperature of 175 ° C., an injection pressure of 9.8 MPa, and a curing time of 120 seconds. A cylindrical molded product having a thickness of 32 mm was obtained. Subsequently, the obtained molded product was post-cured at 175 ° C. for 4 hours to prepare a test piece for evaluating relative permeability. A BH initial magnetization curve is measured in the range of H = 0 to 100 kA / m using a DC / AC magnetization characteristic test apparatus (“MTR-1488” manufactured by Metron Giken Co., Ltd.) for the obtained cylindrical molded product. The maximum value of B / H of the BH initial magnetization curve was taken as the relative permeability.

(Mechanical properties: bending strength)
The resin composition was injection-molded using a low-pressure transfer molding machine (“KTS-30” manufactured by Kotaki Seiki Co., Ltd.) at a mold temperature of 175 ° C., an injection pressure of 9.8 MPa, and a curing time of 120 seconds. A molded product having a length of 4 mm and a length of 80 mm was obtained. Next, the obtained molded product was post-cured at 175 ° C. for 4 hours to prepare a test piece. And the bending strength (MPa) in 25 degreeC of the test piece was measured based on JISK6911.

  The composition and evaluation results of each resin composition are summarized in the table below.

As shown in Table 1, in the evaluation using the resin compositions of Examples 1 to 5 including epoxy resin, aromatic diamine, and magnetic particles, moldability (flow length of spiral flow) and heat resistance ( Both performances (glass transition temperature) (these are trade-offs) were good.
On the other hand, in the resin composition of Comparative Example 1 using a phenolic curing agent instead of an aromatic diamine, the evaluation result of moldability (spiral flow flow length) is clearly inferior to the results of Examples 1-5. It was.

When Examples 1 to 5 and Comparative Example 1 were compared for performances other than moldability and heat resistance, Examples 1 to 5 had a smaller average linear expansion coefficient at 270 to 290 ° C. This indicates that the thermal expansion of the magnetic member formed using the resin compositions of Examples 1 to 5 is small and can be preferably used under high temperature conditions.
In addition, the bending strength was higher in Examples 1 to 5 than in Comparative Example 1. That is, it was shown that the mechanical strength of the magnetic member formed using the resin compositions of Examples 1 to 5 was strong.

DESCRIPTION OF SYMBOLS 10 Winding 20 Magnetic core 30 Exterior member 100 Coil 10B Winding 20B Magnetic core 30B Exterior member 100B Coil 10C Winding 20C Magnetic core 30C Exterior member 100C Integrated inductor

Claims (16)

  A resin composition for molding a magnetic member, comprising an epoxy resin, an aromatic diamine, and magnetic particles. The resin composition according to claim 1,
The resin composition whose melting | fusing point of the said aromatic diamine is 160 degrees C or less. The resin composition according to claim 1 or 2,
The resin composition in which the aromatic diamine contains a compound represented by the following general formula (AM).

In general formula (AM):
Each X is independently selected from the group consisting of a single bond, a linear or branched alkylene group, an ether group, a carbonyl group, an ester group, and a group in which two or more of these are linked. Is the basis of
Y is any group selected from the group consisting of a single bond, a linear or branched alkylene group, an ether group, a carbonyl group, an ester group, and a group in which two or more of these are linked;
R ¹ , R ² and R ³ are each independently a monovalent organic group, a hydroxyl group or a halogen atom when a plurality of R ¹ , R ² and R ³ are present,
k, l and m are each independently an integer of 0 to 4;
n is an integer of 0 or more. The resin composition according to any one of claims 1 to 3,
The resin composition whose content of the said magnetic body particle | grain with respect to the said whole resin composition is 90 mass% or more. The resin composition according to any one of claims 1 to 4, wherein
A resin composition in which the magnetic particles include one or more elements selected from the group consisting of Fe, Cr, Co, Ni, Ag, and Mn. The resin composition according to any one of claims 1 to 5,
A resin composition in which the magnetic particles contain 85 mass% or more of Fe. The resin composition according to any one of claims 1 to 6,
Wherein the magnetic particles, the resin composition median diameter _{D 50} is 0.5~75μm in volume. The resin composition according to any one of claims 1 to 7,
A resin composition in which the epoxy resin contains at least one resin selected from the group consisting of an epoxy resin containing a trisphenylmethane structure and an epoxy resin containing a biphenyl structure. The resin composition according to any one of claims 1 to 8,
A resin composition substantially free of an epoxy curing catalyst. The resin composition according to any one of claims 1 to 9,
The resin composition whose ratio of the mole number of the epoxy group which the said epoxy resin has with respect to the mole number of the amino group which the said aromatic diamine has is 1-3.   The magnetic member shape | molded by the resin composition of any one of Claims 1-10.   A coil comprising the magnetic member according to claim 11 as a magnetic core or an exterior member.   The manufacturing method of the magnetic member which inject | pours the melt of the resin composition of any one of Claims 1-10 into a metal mold | die using a transfer molding apparatus, and obtains the magnetic member which the said melt | cured hardened | cured. Including an epoxy resin and an aromatic diamine,
A resin composition used for forming a magnetic member by mixing with magnetic particles. A mixing step of mixing the resin composition according to claim 14 and magnetic particles to obtain a mixture,
And a molding step of melting and injecting the mixture into a mold and molding the mixture. A first component comprising an epoxy resin and an aromatic diamine;
A magnetic member molding kit comprising a second component containing magnetic particles.

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