JP7102882B2 - Molding material and molded body - Google Patents

Description

The present invention relates to a molding material and a molded body.

With the recent miniaturization and weight reduction of electronic devices, there is a demand for molding materials having high magnetic permeability and high moldability.

Examples of such a molding material include a material containing a magnetic metal powder and a resin. In such a molding material, it is required to improve the adhesion between an inorganic powder such as a magnetic metal powder and a resin.

Therefore, Patent Document 1 discloses that the particle surface of the inorganic powder is subjected to plasma treatment in order to improve the adhesion between the inorganic powder and the resin as a matrix.

Japanese Unexamined Patent Publication No. 2015-137335

However, the molding material obtained by mixing the plasma-treated inorganic powder and the resin has a problem of low fluidity.

Further, in such a molding material, the inorganic powder and the resin are easily separated. For this reason, there is a concern that defects (for example, resin burrs in the molded product) may occur due to the separated resin seeping into an unintended region of the molding mold during molding.

An object of the present invention is to provide a molding material capable of achieving both high fluidity during molding and suppression of resin seepage, and a molded product having good magnetic properties and few molding defects.

Such an object is achieved by the present invention of the following (1) to (9).

(1) Resin and
A magnetic powder containing iron-based particles exhibiting soft magnetism and having an iron content of 85% by mass or more, and fine particles exhibiting soft magnetism and having a particle size of 3 μm or less.
A molding material characterized by having.

(2) The molding material according to (1) above, wherein the iron-based particles and the fine particles have different constituent material compositions.

(3) The molding material according to (2) above, wherein the volume fraction of the fine particles is 3 to 25% by volume of the iron-based particles.

(4) The molding material according to any one of (1) to (3) above, wherein the iron-based particles include first particles and second particles having a composition of a constituent material different from that of the first particles.

(5) The molding material according to (4) above, wherein the average particle size of the first particles is 10 to 200 μm.

(6) The molding material according to (4) or (5) above, wherein the average particle size of the second particle is 1 to 100 μm smaller than the average particle size of the first particle.

(7) The molding material according to any one of (1) to (6) above, wherein the volume fraction of the iron-based particles is 50 to 90% by volume.

(8) A molded product characterized by being a cured product of the molding material according to any one of (1) to (7) above.

(9) The molded product according to (8) above, which has a relative magnetic permeability of 10 or more.

According to the present invention, it is possible to obtain a molding material capable of achieving both high fluidity during molding and suppression of resin seepage.

Further, according to the present invention, a molded product having good magnetic properties and few molding defects can be obtained.

It is a figure which shows the embodiment of the molding material of this invention. FIG. 5 is a cross-sectional view of one particle contained in the magnetic powder shown in FIG. 1, and is a conceptual diagram showing an example of surface treatment.

Hereinafter, the molding material and the molded product of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.
<Molding material>
First, an embodiment of the molding material of the present invention will be described.

FIG. 1 is a diagram showing an embodiment of a molding material of the present invention. Note that FIG. 1 shows the included elements with symbols, and the types of the symbols have no particular meaning.

The molding material 1 shown in FIG. 1 has a resin 2 and a magnetic powder 3 having iron-based particles 3a containing the first particles 31 and the second particles 32 and fine particles 3b. By molding such a molding material 1 by various molding methods, it is possible to manufacture a molded product having a desired shape. Such a molded product exhibits soft magnetism and is used as a magnetic element such as a powder magnetic core. Hereinafter, each element of the molding material 1 will be described in detail.

(resin)
The resin 2 is prepared, for example, in a semi-cured (solid) state. Such a resin 2 is melted by being heated and pressurized at the time of molding, and is molded into a desired shape and is cured. As a result, a molded product that takes advantage of the characteristics of the resin can be obtained.

Examples of the resin 2 include thermosetting resins, thermoplastic resins, and mixtures thereof. When the resin 2 contains a thermosetting resin, it becomes easy to enhance the mechanical properties of the cured product of the molding material 1. Further, since the resin 2 contains the thermoplastic resin, it is possible to reduce the stress of the cured product of the molding material 1 and suppress the deformation of the cured product.

Examples of the thermosetting resin include novolak-type phenol resins such as phenol novolac resin, cresol novolac resin, bisphenol A-type novolak resin, and triazine skeleton-containing phenol novolac resin; unmodified resolephenol resin, tung oil, flaxseed oil, and walnut oil. Resol type phenol resin such as oil-modified resol phenol resin modified with, etc., phenol aralkyl resin, phenol resin such as aralkyl type phenol resin such as biphenyl aralkyl type phenol resin; bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetramethyl Bisphenol F type epoxy resin, Bisphenol S type epoxy resin, Bisphenol E type epoxy resin, Bisphenol M type epoxy resin, Bisphenol P type epoxy resin, Bisphenol Z type epoxy resin and other bisphenol type epoxy resins; Novolak type epoxy resin such as 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 Epoxy resins such as type epoxy resins, adamantan type epoxy resins, fluorene type epoxy resins, and triphenylmethane type epoxy resins; resins having a triazine ring such as urea (urea) resin and melamine resin; unsaturated polyester resins; bismaleimide compounds, etc. Maleimide resin; polyurethane resin; diallyl phthalate resin; silicone resin; benzoxazine resin; polyimide resin; polyamideimide resin; benzocyclobutene resin, novolac type cyanate resin, bisphenol A type cyanate resin, bisphenol E type cyanate resin, tetramethyl Examples thereof include cyanate ester resins such as cyanate resins such as bisphenol F-type cyanate resins. Further, as the thermosetting resin, one of these types may be used alone, or two or more types having different weight average molecular weights may be used in combination, and one type or two or more types thereof may be used. It may be used in combination with a prepolymer.

Of these, as the thermosetting resin, those containing an epoxy resin or a phenol resin are preferably used.

The thermosetting resin is one or more solids selected from the group consisting of a triphenylmethane type epoxy resin, a dicyclopentadiene type epoxy resin, a bisphenol A type epoxy resin, and a tetramethylbisphenol F type epoxy resin. It is preferable to contain the epoxy resin of. According to the resin 2 containing such a thermosetting resin, a molding material 1 having high heat resistance and suitable for molding can be obtained.

Further, the thermosetting resin preferably contains one or more solid phenol resins selected from the group consisting of biphenyl aralkyl type phenol resins and novolak type phenol resins. According to the resin 2 containing such a thermosetting resin, a molding material 1 having high heat resistance and suitable for molding can be obtained.

The thermosetting resin is used in combination with a curing agent, if necessary.

When the thermosetting resin contains a novolak type phenol resin, for example, hexamethylenetetramine is used as the curing agent.

When the thermosetting resin contains an epoxy resin, as a curing agent, for example, amine compounds such as aliphatic polyamines, aromatic polyamines and disiamine diamides, alicyclic acid anhydrides and aromatic acid anhydrides. Acid anhydrides, polyphenol compounds such as novolak type phenol resins, imidazole compounds and the like are used.

When the thermosetting resin contains a maleimide resin, for example, an imidazole compound is used as the curing agent.

Examples of the thermoplastic resin include acrylic resin, polyamide resin (for example, nylon), thermoplastic urethane resin, polyolefin resin (for example, polyethylene, polypropylene, ethylene copolymer, etc.), polycarbonate, polyester resin (for example). For example, polyethylene terephthalate, polybutylene terephthalate, etc.), polyacetal, polyphenylene sulfide, polyether ether ketone, liquid crystal polymer, fluororesin (for example, polytetrafluoroethylene, polyvinylidene fluoride, etc.), modified polyphenylene ether, polysulfone, polyether sulfone, poly Examples thereof include allylate, polyamideimide, polyetherimide, and thermoplastic polyimide. Further, in the molding material 1, one of these types may be used alone, or two or more types having different weight average molecular weights may be used in combination, and one type or two or more types and their prepolymers may be used in combination. May be used in combination with.

Of these, as the thermoplastic resin, those containing an ethylene-based copolymer are preferably used. The ethylene-based copolymer has a characteristic of having a high metal affinity. Therefore, when the resin 2 contains an ethylene-based copolymer, the dispersibility of the magnetic powder 3 in the molding material 1 can be enhanced. As a result, the homogeneity of the molding material 1 can be enhanced and the mechanical strength of the cured product can be enhanced.

Examples of the ethylene-based copolymer include an ethylene-vinyl acetate copolymer, an ethylene-methyl acrylate copolymer, an ethylene-methyl methacrylate copolymer, an ethylene-ethyl acrylate copolymer, and a vinyl chloride-vinyl acetate copolymer. , Ethylene- (meth) acrylate copolymer, ethylene- (meth) methyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer and the like. One type or two or more types are used in combination.

Among these, thermoplastic resins are particularly ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-methyl methacrylate copolymer (EMMA), and ethylene-ethyl acrylate. More preferably, it is at least one selected from the group consisting of copolymers (EEA), at least one of an ethylene-methylacrylate copolymer (EMA) and an ethylene-methylmethacrylate copolymer (EMMA). Is even more preferable.

The ethylene-based copolymer contains ethylene and a vinyl group having a polar group as a monomer unit. The proportion of the vinyl group having a polar group in the ethylene-based copolymer is preferably 5 to 50% by mass, more preferably 10 to 45% by mass, based on the total mass of the ethylene-based copolymer. If the proportion of vinyl groups having polar groups is less than the lower limit, the dispersibility of the magnetic powder 3 in the molding material 1 may decrease. On the other hand, if the proportion of the vinyl group having a polar group exceeds the upper limit value, for example, when an ethylene-based copolymer is used in combination with a thermosetting resin, the affinity between the two may decrease.

Further, the ethylene-based copolymer may contain other monomer units.

Other monomeric units include, for example, α-olefins such as ethylene, propylene, n-butene and isobutylene; acrylic acid and salts thereof; methyl acrylate, ethyl acrylate, n-propyl acrylate, i-acrylic acid. Acrylic acid esters such as propyl, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate; methacrylic acid and salts thereof; methyl methacrylate, Methacrylic acid such as ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, etc. Acid esters; acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamidepropanesulfonic acid and its salts, acrylamidepropyldimethylamine or its acid salts or quaternary salts thereof, N -Acrylamide derivatives such as methylolacrylamide and derivatives thereof; methacrylicamide, N-methylmethacrylicamide, N-ethylmethacrylicamide, methacrylicamide propanesulfonic acid and its salts, methacrylicamidepropyldimethylamine or its acid salts or quaternary salts thereof, Methacrylic amide derivatives such as N-methylol methacrylic amide or derivatives thereof; methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether. Vinyl ethers such as; nitriles such as acrylonitrile and methacrylic nitrile; vinyl halide such as vinyl chloride and vinyl fluoride; vinylidene halide such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; malein Examples thereof include an acid and a salt thereof or an ester thereof or an anhydride thereof; a vinylsilyl compound such as vinyltrimethoxysilane; isopropenyl acetate and the like, and one or more of these may be used in combination. The content of such other monomer units is preferably 10% by mass or less, more preferably 0.1 to 5% by mass, of the ethylene-based copolymer.

Further, the ethylene-based copolymer may have a functional group such as a hydroxyl group, a carboxyl group, an acid anhydride group, an amino group or a trimethoxysilyl group in the molecular chain or at the end of the molecular chain.

Further, the above-mentioned ethylene-based copolymer may be a saponified product thereof. This saponified product is obtained by saponifying an ethylene-based copolymer with an alkali metal compound such as sodium hydroxide, potassium hydroxide, sodium alkoxide, or potassium alkoxide.

On the other hand, the resin 2 preferably contains both a thermosetting resin and a thermoplastic resin. As a result, it is possible to reduce the stress of the cured product while enhancing the mechanical properties of the cured product of the molding material 1. As a result, for example, it is possible to realize a magnetic element having high mechanical strength and less likely to be deformed or cracked.

In this case, the content of the thermoplastic resin in the resin 2 is not particularly limited, but is preferably 1 to 50% by mass, more preferably 5 to 40% by mass. When the content of the thermoplastic resin is less than the lower limit, the stress of the cured product of the molding material 1 can be sufficiently reduced depending on the type of the thermosetting resin contained in the resin 2 and the blending ratio of the resin 2. May not be possible. On the other hand, if the content of the thermoplastic resin exceeds the upper limit value, the moldability of the molding material 1 may decrease depending on the type of the thermosetting resin contained in the resin 2, the blending ratio of the resin 2, and the like.

The glass transition temperature Tg of the cured product of the molding material 1 is not particularly limited, but is preferably 150 ° C. or higher, more preferably 170 ° C. or higher, and even more preferably 190 ° C. or higher. By using such a molding material 1, a molding material 1 capable of producing a molded body suitable for use in a high temperature environment can be obtained.

The glass transition temperature Tg of the molding material 1 is measured by, for example, a thermomechanical analyzer (TMA100 manufactured by Seiko Instruments Inc.).

The mass fraction of such resin 2 is preferably 2 to 10% by mass, more preferably 3 to 8% by mass of the molding material 1. As a result, the content of the resin 2 is optimized, so that a molding material 1 capable of achieving both high fluidity during molding and suppression of resin seepage can be obtained.

The mass fraction of the resin 2 is calculated including the mass of the curing agent when the curing agent is used in combination with the resin 2.

(Magnetic powder)
As described above, the magnetic powder 3 has iron-based particles 3a containing the first particles 31 and the second particles 32, and fine particles 3b.

-Iron-based particles-
Of these, the first particle 31 contained in the iron-based particles 3a is a particle that exhibits soft magnetism and has an iron content of 85% by mass or more.

Soft magnetism refers to ferromagnetism with a small coercive force. Generally, ferromagnetism having a coercive force of 800 A / m or less is called soft magnetism.

Examples of the constituent material of the first particle 31 include a metal material having an iron content of 85% by mass or more as a constituent element. Such a metal material having a high iron content as a constituent element exhibits soft magnetism having relatively good magnetic properties such as magnetic permeability and magnetic flux density. Therefore, for example, when molded into a dust core or the like, a molding material capable of exhibiting good magnetic properties can be obtained.

Examples of the form of this metal material include simple substances, solid solutions, eutectic systems, alloys such as intermetallic compounds, and the like. By using the first particle 31 made of such a metal material, it is possible to obtain a molding material 1 having excellent magnetic characteristics derived from iron, that is, magnetic characteristics such as high magnetic permeability and high magnetic flux density. ..

Moreover, the said metal material may contain an element other than iron as a constituent element. Elements other than iron include, for example, B, C, N, O, Al, Si, P, S, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Cd. , In, Sn and the like, and one or a combination of two or more of these is used.

Specific examples of the above metal materials include pure iron, silicon steel, iron-cobalt alloy, iron-nickel alloy, iron-chromium alloy, iron-aluminum alloy, carbonyl iron, stainless steel, or any of these. Examples thereof include composite materials containing one type or two or more types.

The average particle size of the iron-based particles 3a is not particularly limited as long as it exceeds 3 μm, but is preferably 4 to 180 μm, more preferably 5 to 150 μm, and even more preferably 7 to 100 μm. When the average particle size of the iron-based particles 3a is within the above range, the fluidity of the molding material 1 can be further enhanced.

If the average particle size of the iron-based particles 3a is less than the lower limit, the moldability of the molding material 1 may decrease depending on the specific gravity of the constituent material, the particle shape, and the like. On the other hand, if the average particle size of the iron-based particles 3a exceeds the upper limit value, the iron-based particles 3a are likely to settle in the molding material 1 depending on the specific gravity of the constituent material, the particle shape, and the like, and the uniformity may be lowered. There is.

The average particle size of the first particles 31 is not particularly limited, but is preferably 10 to 200 μm, more preferably 12 to 150 μm, and even more preferably 15 to 100 μm. When the average particle size of the first particles 31 is within the above range, the magnetic properties such as the magnetic permeability of the molding material 1 can be further enhanced.

The average particle size of the iron-based particles 3a and the first particle 31 means a volume average particle size, and can be measured using a laser diffraction type particle size distribution measuring device.

Further, the constituent material of the first particle 31 may be a crystalline material, an amorphous material, or a material in which these are mixed in the particles.

Further, the iron-based particles 3a may be a mixture of the first particles 31 made of a crystalline material and the first particles 31 made of an amorphous material. As a result, two types of first particles 31 having different surface hardnesses are mixed. As a result, the interaction between the first particles 31 at the time of flow is optimized, and higher fluidity is ensured.

The sphericity of the first particle 31 is not particularly limited, but is preferably 0.60 to 1.00, and more preferably 0.70 to 1.00. When the sphericity of the first particle 31 is within the above range, the fluidity of the molding material 1 can be further enhanced.

In the scanning electron microscope (SEM) image of the first particle 31, the sphericality of the first particle 31 is the diameter equivalent to the equal area circle / the diameter of the circumscribing circle when a perfect circle equal to the area is defined as an equal area circle. You can ask. Then, the equivalent area circle equivalent diameter / circumscribed circle diameter is calculated for 10 or more arbitrarily selected first particles 31, and the average value thereof is defined as the “sphericity of the first particles 31”.

The second particle 32 is a particle that exhibits soft magnetism and has a composition of a constituent material different from that of the first particle 31.

The constituent material of the second particle 32 is appropriately selected from the above-mentioned materials as the constituent material of the first particle 31.

When the composition of the constituent materials is different, it means that the content of the constituent elements is different by 1% by mass or more.

By using the second particle 32 whose composition of the constituent material is different from that of the first particle 31 in this way, two types of particles having different surface chemical states and surface hardness are mixed. As a result, the interaction between the first particle 31 and the second particle 32 during flow is optimized, and higher fluidity is ensured.

The average particle size of the second particle 32 is not particularly limited, but is preferably different from the average particle size of the first particle 31. That is, the average particle size of the second particle 32 may be larger than the average particle size of the first particle 31, but it is preferably smaller. As a result, even if the first particles 31 having a relatively large particle size are contained, the decrease in the fluidity of the molding material 1 can be suppressed. That is, the high fluidity of the molding material 1 can be ensured by the second particle 32 while ensuring the excellent magnetic characteristics derived from the first particle 31.

When the average particle size of the second particle 32 is smaller than the average particle size of the first particle 31, the difference between the average particle size of the first particle 31 and the average particle size of the second particle 32 is the flow of the molding material 1. It is appropriately set in consideration of the property, but as an example, it is preferably 1 to 100 μm, more preferably 3 to 80 μm, further preferably 5 to 60 μm, and particularly preferably 8 to 50 μm. preferable. Thereby, the fluidity of the molding material 1 can be further increased.

That is, if the difference in average particle size is less than the lower limit, the effect of increasing fluidity may decrease. Further, since the difference in particle size between the first particle 31 and the second particle 32 becomes smaller, the action of the second particle 32 being arranged so as to fill the gap between the first particles 31 is weakened, and the filling property of the magnetic material is weakened. May decrease. On the other hand, if the difference in the average particle size exceeds the upper limit value, the particle size of the second particle 32 becomes too small depending on the particle size of the first particle 31, and the fluidity of the molding material 1 may decrease. ..

The average particle size of the second particle 32 means a volume average particle size, and can be measured using a laser diffraction type particle size distribution measuring device.

Further, the constituent material of the second particle 32 may be a crystalline material, an amorphous material, or a material in which these are mixed.

The sphericity of the second particle 32 is not particularly limited, but is preferably 0.60 to 1.00, and more preferably 0.70 to 1.00. When the sphericity of the second particle 32 is within the above range, the fluidity of the molding material 1 can be further enhanced.

In the scanning electron microscope (SEM) image of the second particle 32, the sphericality of the second particle 32 is the same area circle equivalent diameter / circumscribing circle diameter when a perfect circle equal to the area is defined as an equal area circle. You can ask. Then, the equivalent area circle equivalent diameter / circumscribed circle diameter is calculated for 10 or more arbitrarily selected second particles 32, and the average value thereof is defined as the “sphericity of the second particle 32”.

Further, the second particle 32 may be added as needed or may be omitted.

Further, the magnetic material powder 3 may contain soft magnetic particles other than the first particle 31 and the second particle 32, for example, Ni-based soft magnetic particles, Co-based soft magnetic particles, and the like.

Further, at least one of the first particle 31 and the second particle 32 may be surface-treated.

The surface treatment refers to an operation for modifying the surface of particles. Examples of this operation include treating the surface of the particles with a coupling agent and treating the particles with plasma, as will be described later.

FIG. 2 is a cross-sectional view of one particle contained in the magnetic powder 3 shown in FIG. 1, and is a conceptual diagram showing an example of surface treatment.

The first particle 31'shown in FIG. 2 has a functional group represented by the following general formula (1) bonded to the surface 31S of the first particle 31. That is, the first particle 31'shown in FIG. 2 is formed by covering the surface 31S of the first particle 31 with the functional group of the following general formula (1) as a result of surface treatment.

* -OXR ... (1)
[In the formula, R represents an organic group, X is Si, Ti, Al, or Zr, and * is one of the atoms constituting the first particle 31. ]
Further, such a functional group is a residue formed by surface treatment with various coupling agents such as a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, and a zirconium coupling agent. In particular, it is preferably a residue of a coupling agent selected from the group consisting of a silane-based coupling agent and a titanium-based coupling agent. As a result, when the magnetic powder 3 is blended with the resin composition to obtain the molding material 1, the fluidity thereof can be further enhanced.

As will be described in detail later, it is preferable that the first particles 31 satisfy a predetermined viscosity ratio (thixo ratio) when blended in the resin composition. From this point of view, by performing the surface treatment as described above, the viscosity ratio of the compound can be controlled and a predetermined condition can be satisfied.

Further, when the functional groups as described above are bonded, plasma treatment may be performed in advance as a part of the surface treatment on the first particles 31. For example, by performing oxygen plasma treatment, an OH group is generated on the surface 31S of the first particle 31, and as shown in FIG. 2, the bond between the first particle 31 and the residue of the coupling agent via an oxygen atom is formed. Becomes easier. As a result, the functional group can be bonded more firmly.

It can be confirmed by, for example, a Fourier transform infrared spectrophotometer that the first particle 31 and the residue of the coupling agent are bonded to each other via an oxygen atom in the first particle 31'.

Further, the surface treatment as described above may be applied to the second particle 32, or may be applied to both the first particle 31 and the second particle 32.

From the viewpoint of increasing the fluidity of the molding material 1, only the first particles 31 may be surface-treated. As a result, the surface states of the first particle 31 and the second particle 32 are different, so that each exhibits different behavior in the interaction with the resin 2, and as a result, contributes to increasing the fluidity.

The first particles 31 preferably satisfy the following viscosity ratio (thixo ratio) under a temperature condition of 30 ° C. when blended in a resin composition containing an epoxy resin and a phenol resin.

First, the first particles 31 are blended with the resin composition, and the viscosity is measured with a viscoelasticity measuring device.

Then, the viscosity when the shear shear rate is 1, is η1, and the viscosity when the shear shear rate of the viscoelasticity measuring device is 10.

At this time, it is preferable that η1 / η10 <3.4 is satisfied.

The epoxy resin used in this measurement is a polycondensate of allylated bisphenol A and epichlorohydrin.

The phenol resin used in this measurement is a 2-allylphenol formaldehyde polycondensate.

When the first particles 31 are blended into the resin composition, the amount of the first particles 31 used is in the range of 15 to 50 parts by volume with respect to 100 parts by volume of the total of the resin composition.

The amount of the epoxy resin used is 30 to 60% by volume in the resin composition, and the amount of the phenol resin used is 10 to 30% by volume in the resin composition.

The total amount of the epoxy resin and the phenol resin used is 50 to 85% by volume in the resin composition.

A solvent may be used in the resin composition, and examples of the solvent include butyl cellosolve acetate and 1-methoxy-2-propanol.

The viscosity ratio (thixo ratio) η1 / η10 is less than 3.4 as described above.
It is preferably 1.5 or more and less than 3.4, more preferably 2.0 or more and 3.0 or less, further preferably 2.1 or more and less than 3.0, and 2.2 or more and 2. It is particularly preferably 8 or less. When the viscosity ratio (thixo ratio) η1 / η10 is within the above range, the fluidity of the molding material 1 can be further enhanced.

The viscosity was measured by using a viscoelasticity measuring device (“RheoStress RS150” manufactured by HAAKE) to apply shear shear to the resin composition containing the first particles 31 between a gap of 50 to 1000 μm in a parallel plate of 20 mmφ. It can be measured while.

Further, in order for the viscosity ratio to satisfy the above range, a method of performing a surface treatment such as oxygen plasma treatment or coupling agent treatment as described above can be mentioned. Among them, it is preferable to perform both oxygen plasma treatment and coupling agent treatment, and at that time, a coupling agent selected from the group consisting of a silane-based coupling agent and a titanium-based coupling agent is used as the coupling agent. Is more preferable.

It should be noted that such a surface treatment may be applied as needed or may be omitted.

Further, another coating treatment may be applied to the base of the surface treatment described above. Examples of such a coating treatment include a resin coating such as a silicone resin, a silica coating, and the like. By applying such a coating treatment, the insulating property of the iron-based particles 3a can be further enhanced.

It should be noted that such a coating treatment may be performed as needed or may be omitted.

Further, this coating treatment may be applied alone, not as a base for the surface treatment described above.

The volume fraction of such iron-based particles 3a is preferably 50 to 90% by volume, more preferably 55 to 85% by volume of the molding material 1. As a result, the content of the iron-based particles 3a becomes sufficiently high, so that the molding material 1 having good magnetic properties can be obtained.

If the volume fraction of the iron-based particles 3a is less than the lower limit, the magnetic characteristics of the molding material 1 may deteriorate depending on the magnetic characteristics of the iron-based particles 3a. Further, when the volume fraction of the iron-based particles 3a exceeds the upper limit value, the volume fraction of the resin 2 is relatively lowered, so that the fluidity of the molding material 1 is lowered and the mechanical properties after curing are deteriorated. It may decrease.

On the other hand, although it varies depending on the specific gravity of each component, an example of the mass fraction of the iron-based particles 3a is preferably 75 to 98% by mass, more preferably 80 to 97% by mass of the molding material 1. As a result, the molding material 1 having good magnetic properties can be obtained as in the case of the volume fraction.

-Microparticles-
The molding material 1 contains fine particles 3b showing soft magnetism and having a particle size of 3 μm or less.

As described above, the molding material 1 containing such fine particles 3b exhibits high fluidity during molding, and exudation of the resin 2 during molding is suppressed. Therefore, the moldability of the molding material 1 is improved, and the filling property and the uniformity of the magnetic material powder 3 can be further improved, so that good magnetic properties can be obtained in the molded body. Further, by suppressing the exudation of the resin 2, the generation of resin burrs and the like in the molded product is suppressed. In addition, it is possible to prevent the component balance of the molding material 1 from being lost due to the exudation of the resin 2 and the mechanical properties of the molded product from being deteriorated. Therefore, a molded product with few molding defects can be obtained.

The reason why the exudation of the resin 2 is suppressed is that the exuding path of the resin 2 at the time of molding is clogged with the fine particles 3b, so that this path is blocked.

Further, by including the fine particles 3b, the volume fraction of the magnetic material in the molding material 1 can be further increased. That is, since the fine particles 3b easily enter the gap, the filling property of the magnetic material is improved accordingly. As a result, the magnetic properties of the molding material 1 can be further enhanced.

As the constituent material of the fine particles 3b, for example, the above-mentioned materials may be appropriately selected as the constituent material of the first particle 31, and other soft magnetic materials (for example, soft ferrite, Ni-based soft magnetic material, Co-based soft) may be appropriately selected. It may be a magnetic material, etc.).

Further, the composition of the constituent material of the fine particles 3b may be the same as or different from the composition of the constituent material of the first particle 31 and the second particle 32.

When the composition of the constituent materials is different, it means that the content of the constituent elements is different by 1% by mass or more.

By using the fine particles 3b whose constituent material composition is different from that of the first particle 31 and the second particle 32 in this way, particles having different surface chemical states and surface hardness are mixed in the molding material 1. Become. As a result, the interaction between the iron-based particles 3a and the fine particles 3b during flow is optimized, and higher fluidity is ensured.

The particle size of the fine particles 3b is not particularly limited as long as it is 3 μm or less, but it is preferable that the fine particles 3b of 0.1 to 2.8 μm are contained. Such a particle size is a particle size required for the fine particles 3b to fill the exudation path of the resin 2, and is a particle size that easily flows together with the melt of the resin 2.

The sphericity of the fine particles 3b is not particularly limited, but is preferably 0.30 to 1.00, and more preferably 0.50 to 1.00. When the sphericity of the fine particles 3b is within the above range, the fluidity of the molding material 1 is ensured by utilizing the rolling of the fine particles 3b itself, while the fine particles 3b are easily clogged in the gaps and the like, and the resin 2 is stained. It becomes easier to suppress the ejection. That is, it is possible to achieve both the fluidity of the molding material 1 and the suppression of the exudation of the fine particles 3b.

The sphericality of the fine particles 3b is determined by the equivalent area circle diameter / circumscribed circle diameter when a perfect circle equal to the area is defined as an equal area circle in the scanning electron microscope (SEM) image of the fine particles 3b. Can be done. Then, the equivalent area circle equivalent diameter / circumscribed circle diameter is calculated for 10 or more fine particles 3b arbitrarily selected, and the average value thereof is defined as the "sphericity of the fine particles 3b".

As described above, the molding material 1 may contain fine particles 3b having a particle size of 3 μm or less, but the content of the fine particles 3b in the magnetic powder 3 is defined as a relative ratio to the iron-based particles 3a. To.

That is, the volume fraction of the fine particles 3b is preferably 3 to 25% by volume, more preferably 5 to 20% by volume of the iron-based particles 3a. The mass fraction of the fine particles 3b is preferably 3 to 50% by mass, more preferably 5 to 30% by mass of the iron-based particles 3a. As a result, the content of the fine particles 3b is optimized, so that the molding material 1 having sufficient fluidity and capable of more reliably suppressing the seepage of the resin 2 can be obtained.

When the volume fraction or mass fraction of the fine particles 3b is less than the lower limit, the effect of improving the fluidity of the fine particles 3b is reduced, so that the fluidity of the molding material 1 is lowered and the resin 2 is reduced. The effect of suppressing exudation may also be reduced. Further, when the volume fraction or mass fraction of the fine particles 3b exceeds the upper limit value, the volume fraction of the iron-based particles 3a or the volume fraction of the resin 2 decreases relatively. Therefore, the magnetic properties and fluidity of the molding material 1 may be deteriorated.

On the other hand, although it differs depending on the specific gravity of each component, an example of the mass fraction of the fine particles 3b is preferably 0.5 to 25% by mass, more preferably 3 to 20% by mass of the molding material 1. .. As a result, a molding material 1 having sufficient fluidity and capable of more reliably suppressing the seepage of the resin 2 can be obtained as in the case of the volume fraction.

The particle size and volume fraction of the fine particles 3b can be measured using a laser diffraction type particle size distribution measuring device.

(Non-magnetic powder)
The molding material 1 may contain a non-magnetic material powder exhibiting non-magnetism, if necessary.

The non-magnetic powder is a powder that is non-magnetic, has an average particle size of 3 μm or less, and has an average particle size smaller than that of iron-based particles 3a.

Non-magnetic means having no ferromagnetism.

As described above, the molding material 1 containing such a non-magnetic material powder exhibits higher fluidity during molding, and the exudation of the resin 2 during molding is further suppressed. Therefore, the moldability of the molding material 1 becomes better, and the filling property and the uniformity of the magnetic material powder 3 can be further improved, so that particularly good magnetic properties can be obtained in the molded body. Further, by suppressing the exudation of the resin 2, the generation of resin burrs and the like in the molded product is suppressed. In addition, it is possible to prevent the component balance of the molding material 1 from being lost due to the exudation of the resin 2 and the mechanical properties of the molded product from being deteriorated. Therefore, a molded product with few molding defects can be obtained.

The reason why the exudation of the resin 2 is suppressed is that the exuding path of the resin 2 during molding is blocked by the non-magnetic powder.

Examples of the constituent material of the non-magnetic powder include a ceramic material, a glass material, and the like, and a material containing at least one of these is used. Of these, those containing ceramic materials are preferably used. Since such non-magnetic powder acts to reduce the melt viscosity of the molding material 1, the fluidity of the molding material 1 can be further increased.

Examples of the ceramic material include oxide-based ceramic materials such as silica, alumina, zirconia, titania, magnesia, and calcia, nitride-based ceramic materials such as silicon nitride and aluminum nitride, and carbide-based materials such as silicon carbide and boron carbide. Examples include ceramic materials. Further, one of these may be used alone, or a mixture containing one of these may be used.

Further, the ceramic material preferably contains silica in particular. Silica has a high affinity with the resin 2 and a high insulating property, and is therefore useful as a constituent material of the non-magnetic powder used in the molding material 1.

The true specific gravity of the constituent material of the non-magnetic material powder is preferably 1.0 to 6.0 g / cm ³ , more preferably 1.2 to 5.0 g / cm ³ , and 1.5 to 4 It is more preferably .5 g / cm ³ . Since such non-magnetic powder has a small specific gravity, it easily flows together with the melt of the resin 2. Therefore, when the melt of the resin 2 flows toward the gap of the molding mold during molding, the non-magnetic powder easily flows together with the melt. As a result, the gap is closed by the non-magnetic material powder, and the exudation of the resin 2 can be suppressed more reliably. The gap between the molding molds includes, for example, a gap (clearance) between the plunger and the cylinder of the transfer molding machine.

The average particle size of the non-magnetic powder is not particularly limited as long as it is 3 μm or less, but it is preferably 0.1 to 2.8 μm, and more preferably 0.5 to 2.5 μm. Such a particle size is a particle size required for the non-magnetic material powder to fill the exudation path of the resin 2, and is a particle size that easily flows together with the melt of the resin 2.

The average particle size of the non-magnetic material powder means a volume average particle size, and can be measured using a laser diffraction type particle size distribution measuring device.

The average particle size of the non-magnetic material powder may be 3 μm or less and smaller than the average particle size of the magnetic material powder 3, but the difference is preferably 5 μm or more, preferably 10 to 100 μm. More preferably, it is 15 to 60 μm.

The sphericity of the non-magnetic powder is not particularly limited, but is preferably 0.50 to 1.00, and more preferably 0.75 to 1.00. When the sphericity of the non-magnetic powder is within the above range, the fluidity of the molding material 1 is ensured by utilizing the rolling of the non-magnetic powder itself, while the non-magnetic powder is easily clogged in gaps and the like, and the resin. It becomes easy to suppress the exudation of 2. That is, it is possible to achieve both the fluidity of the molding material 1 and the suppression of the exudation of the resin 2.

In the scanning electron microscope (SEM) image of the non-magnetic material powder, the sphericality of the non-magnetic material powder is the diameter equivalent to the equal area circle / circumscribed circle diameter when a perfect circle equal to the area is defined as an equal area circle. You can ask. Then, the equivalent area circle equivalent diameter / circumscribed circle diameter is calculated for 10 or more arbitrarily selected non-magnetic material powders, and the average value thereof is defined as the “spherical degree of the non-magnetic material powder”.

The volume fraction of such a non-magnetic material powder is preferably 3 to 25% by volume, more preferably 5 to 20% by volume of the magnetic material powder 3. The mass fraction of the non-magnetic material powder is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass of the magnetic material powder 3. As a result, the content of the non-magnetic powder is optimized, so that the molding material 1 having sufficient fluidity and capable of more reliably suppressing the seepage of the resin 2 can be obtained.

When the volume fraction or mass fraction of the non-magnetic material powder is less than the lower limit, the effect of improving the fluidity of the non-magnetic material powder is reduced, so that the fluidity of the molding material 1 is lowered and the resin is used. The effect of suppressing the exudation of 2 may also be reduced. Further, when the volume fraction or mass fraction of the non-magnetic material powder exceeds the upper limit value, the volume fraction or mass fraction of the magnetic material powder 3 is relatively reduced, or the volume fraction or mass fraction of the resin 2 is relatively reduced. Since the rate is reduced, the magnetic properties and fluidity of the molding material 1 may be deteriorated.

On the other hand, although it differs depending on the specific gravity of each component, an example of the mass fraction of the non-magnetic material powder is preferably 0.5 to 15% by mass, preferably 0.7 to 10% by mass of the molding material 1. Is more preferable. As a result, a molding material 1 having sufficient fluidity and capable of more reliably suppressing the seepage of the resin 2 can be obtained as in the case of the volume fraction.

(Other ingredients)
The molding material 1 may contain other components other than the above-mentioned components.

Examples of other components include solvents, mold release agents, curing accelerators, adhesion aids, colorants, antioxidants, corrosion resistant agents, fillers, dyes, pigments, flame retardants and the like.

The molding material 1 as described above may be in the form of powder, granules, tablets formed by locking into a desired shape, or the like.
<Manufacturing method of molding material>
Next, an example of a method for producing the molding material 1 will be described. Here, an example in which the molding material 1 is manufactured by subjecting the first particles 31 to a surface treatment will be described.

In the method for producing the molding material 1 according to this example, the step (i) of subjecting the first particle 31 to the plasma treatment and the reaction of the first particle 31 subjected to the plasma treatment in the step (i) with the coupling agent. The process (iii) includes a step (iii) of mixing the magnetic powder 3, the resin 2, and other additives containing the first particles 31 reacted with the coupling agent to obtain the molding material 1.

(Step (i))
First, the first particle 31 is subjected to plasma treatment. At this time, it is preferable to uniformly apply plasma treatment to the surface 31S of the first particles 31. As a result, the surface 31S of the first particle 31 can be activated and the coupling agent can be reacted efficiently.

In order to perform the plasma treatment uniformly, for example, a method of dispersing the first particles 31 in the air and performing the plasma treatment can be mentioned.

Further, the plasma treatment is preferably an oxygen plasma treatment. As a result, the OH group can be efficiently modified with respect to the surface 31S of the first particle 31.

The pressure of the oxygen plasma treatment is not particularly limited, but is preferably 100 to 200 Pa, and more preferably 120 to 180 Pa.

The flow rate of the processing gas in the oxygen plasma treatment 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, more preferably 10 to 40 minutes.

Further, the argon plasma treatment may be further performed before the oxygen plasma treatment is performed. As a result, an active site for modifying the OH group can be formed on the surface 31S of the first particle 31, so that the modification of the OH group can be performed more efficiently.

The pressure of the argon plasma treatment is not particularly limited, but is preferably 10 to 100 Pa, and more preferably 15 to 80 Pa.

The flow rate of the processing gas in the argon plasma treatment 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, more preferably 200 to 400 W.

The treatment time of the argon plasma treatment is preferably 5 to 60 minutes, more preferably 10 to 40 minutes.

(Step (ii))
Next, the first particle 31 immediately after the plasma treatment in the step (i) is reacted with the coupling agent. As this method, for example, the first particle 31 immediately after the plasma treatment in the step (i) is immersed in a diluted solution of the coupling agent, or the coupling agent is directly sprayed on the first particle 31. The method can be mentioned. As a result, the reaction becomes easier to proceed, and the surface 31S of the first particle 31 becomes easier to modify. Immediately after the plasma treatment is applied, it means a range of 0 to 24 hours after the plasma treatment is applied.

Examples of the coupling agent include a silane-based coupling agent, a titanium-based coupling agent, a zirconia-based coupling agent, an aluminum-based coupling agent, and the like.

Of these, one or more selected from the group consisting of silane-based coupling agents and titanium-based coupling agents is particularly preferable. Thereby, the fluidity of the molding material 1 can be further increased.

The amount of the coupling agent used is preferably 0.05 to 1 part by mass, more preferably 0.1 to 0.5 part by mass with respect to 100 parts by mass of the first particle 31.

Examples of the solvent for reacting with the coupling agent include methanol, ethanol, isopropyl alcohol and the like.

The amount of the coupling agent used is preferably 0.1 to 2 parts by mass, more preferably 0.5 to 1.5 parts by mass with respect to 100 parts by mass of the solvent.

The reaction time with the coupling agent (for example, the immersion time in the diluted solution) is preferably 1 to 24 hours.

According to such a production method, the magnetic powder 3 capable of enhancing the fluidity when blended with the resin composition can be efficiently produced.

(Step (iii))
Next, the magnetic powder 3, the resin 2, and other additives containing the first particles 31 reacted with the coupling agent are mixed using a mixer, and then kneaded at 120 ° C. for 5 minutes using a roll. To obtain a kneaded product.

Next, the kneaded product is cooled and then pulverized to obtain a powdered molding material 1.

After that, if necessary, the molding material 1 in the form of granules or powder may be locked and compacted into a tablet.

Such a molding material 1 is molded by various molding methods such as a transfer molding method, an injection molding method, an extrusion molding method, and a press molding method. As a result, the resin 2 melts and flows, and is formed into a desired shape.

After that, the resin 2 is cured to obtain a molded product. Such molded bodies are used, for example, in automobile reactors, inductors, motor magnet fixing materials, and the like.
<Molded body>
Next, an embodiment of the molded product of the present invention will be described.

The molded product according to the present embodiment is a cured product of the above-mentioned molding material 1 (molding material according to the embodiment). That is, in this molded product, the resin 2 is cured by molding the molding material 1 while being heated, and the magnetic material powder 3 and the non-magnetic material powder are bound via the resin 2. As a result, a molded product having good magnetic properties and few molding defects can be obtained.

Such a molded product preferably has a relative magnetic permeability of 10 or more, more preferably 15 or more, and even more preferably 18 or more. Since such a molded product has good magnetic characteristics, it contributes to the realization of high-performance magnetic devices such as reactors, inductors, and motors. Further, as the magnetic permeability of the molded product is increased, the size of these magnetic devices can be reduced.

The relative magnetic permeability of the molded product is measured as follows.

First, the molding material 1 is molded by a low-pressure transfer molding machine to obtain a cylindrical molded product having a diameter of 16 mm and a height of 32 mm.

Next, the magnetization curve (BH curve) of the obtained molded product is acquired using an electromagnet type magnetizer and an AC / DC magnetization characteristic recorder (MTR-1488 manufactured by Metron Giken Co., Ltd.). Then, the specific magnetic permeability is calculated by obtaining the maximum value (maximum magnetic permeability) of the slope of the obtained initial magnetization curve and dividing the obtained maximum magnetic permeability by the magnetic permeability in vacuum.

Although the present invention has been described above based on the embodiments, the present invention is not limited thereto.

For example, the molding material and the molded product of the present invention may be those in which any element is added to the above-described embodiment.
Hereinafter, an example of the reference form will be added.
1. 1.
With resin
A magnetic powder containing iron-based particles exhibiting soft magnetism and having an iron content of 85% by mass or more, and fine particles exhibiting soft magnetism and having a particle size of 3 μm or less.
A molding material characterized by having.
2.
The iron-based particles and the fine particles have different constituent material compositions. The molding material described in.
3. 3.
The volume fraction of the fine particles is 3 to 25% by volume of the iron-based particles. The molding material described in.
4.
The iron-based particles include a first particle and a second particle whose constituent material composition is different from that of the first particle. Or 3. The molding material according to any one of.
5.
The average particle size of the first particles is 10 to 200 μm. The molding material described in.
6.
4. The average particle size of the second particle is 1 to 100 μm smaller than the average particle size of the first particle. Or 5. The molding material described in.
7.
The volume fraction of the iron-based particles is 50 to 90% by volume. Or 6. The molding material according to any one of.
8.
1. 1. Or 7. A molded product, which is a cured product of the molding material according to any one of the above.
9.
7. The relative magnetic permeability is 10 or more. The molded article according to.

Next, specific examples of the present invention will be described.

1. 1. Manufacture of molding material (Example 1)
[1] Plasma treatment of the first particles of iron-based particles First, an amorphous magnetic powder (manufactured by Epson Atmix Co., Ltd., KUAMET6B2) was used using a rotary tabletop vacuum plasma device (manufactured by Kai Semiconductor Co., Ltd., YHS-DΦS). , Spherical degree 0.85) was pretreated with Ar plasma (gas type Ar, pressure 20 Pa, flow rate 50 mL / min, output 300 W, treatment time 40 minutes). Next, using the same device, O ₂ plasma treatment (gas type H ₂ O bubbling / O ₂ , pressure 150 Pa, flow rate 3000 mL / min, output 300 W, treatment time 40 minutes) was carried out.

[2] Coupling agent treatment for the first particles of iron-based particles Next, the powder (20 g) after the completion of the O ₂ plasma treatment was added to the silane coupling agent (0.3 g) 5 minutes after the O ₂ plasma treatment. , Shin-Etsu Chemical Co., Ltd., KBM303) and ethanol (20 g) were immersed in the solution, and the mixture was stirred overnight with a shaker. Next, the solid content was separated by a centrifuge, washed with ethanol three times, and dried at 85 ° C. for 2 hours to obtain surface-treated amorphous iron powder (first particles).

[3] Mixing Treatment Next, as the first particles of the iron-based particles, an amorphous magnetic powder (manufactured by Epson Atmix Co., Ltd., KUAMET6B2, sphericity 0.85) subjected to the above-mentioned surface treatment was prepared.

Further, as the second particles of the iron-based particles, alloy steel powder (manufactured by Daido Steel Co., Ltd., DAPMSC5, sphericity 0.80) was prepared. The volume fraction of the iron-based particles composed of the first particles and the second particles was calculated from the specific gravity and mass fraction of each component, and was 69.6% by volume of the entire molding material.

Further, as fine particles, carbonyl iron powder (manufactured by BASF, CIP-HQ, sphericity 0.90) was prepared. The volume fraction of the fine particles was calculated from the specific gravity and mass fraction of each component, and was 11.7% by volume of the iron-based particles.

Further, as a thermosetting resin, an epoxy resin (Trisphenol type epoxy resin E1032H60 manufactured by Mitsubishi Chemical Corporation) was prepared.

Moreover, as a curing agent, a novolak type phenol resin (manufactured by Sumitomo Bakelite Co., Ltd., PR-HF-3) was prepared.

In addition, as other components (additives), a mold release agent (manufactured by Clariant Chemicals Corporation, ester wax WE-4) and an imidazole-based curing accelerator (manufactured by Shikoku Chemicals Corporation, Curesol 2PZ-PW) Prepared.

Next, each of these components was mixed to obtain a molding material. The characteristics, blending ratio, etc. of each component are as shown in Table 2.

(Examples 2 to 8 and Comparative Examples 1 and 2)
A molding material was obtained in the same manner as in Example 1 except that each component and compounding ratio of the molding material were changed as shown in Table 2. The volume fraction of the iron-based particles was 65 to 85% by volume of the entire molding material. The volume fraction of the fine particles was 5 to 20% by volume of the iron-based particles.

The alloy composition of the constituent materials of the magnetic powder shown in Table 2 is as shown in Table 1. The alloy composition of "carbonyl iron powder YW1" in Table 2 is almost the same as the alloy composition of carbonyl iron powder CIP-HQ shown in Table 1.

The symbols shown in Table 2 have the following meanings.

NC3000: Nihon Kayaku Co., Ltd., Biphenyl aralkyl type epoxy resin BAPP: Wakayama Seika Kogyo Co., Ltd., 2,2-Bis [4- (4-aminophenoxy) phenyl] Propane ABP-N: Mitsui Kagaku ( Made by Co., Ltd., 1,3-bis- (3-aminophenoxy) benzene and 3- (3'-(3''-aminophenoxy) phenyl) amino-1- (3'-(3''-aminophenoxy)) Phenoxy) Benzene mixture 2. Evaluation of molding material 2.1 Evaluation of fluidity The molding materials obtained in each Example and each Comparative Example were evaluated to determine the amount of spiral flow using a low-pressure transfer molding machine and a spiral flow mold.

Specifically, "KST-30" manufactured by Kotaki Seiki Co., Ltd. was prepared as a low-pressure transfer molding machine. Further, as a spiral flow mold, a spiral flow mold conforming to EMMI-1-66 was prepared. Then, the plunger of the low-pressure transfer molding machine was lowered to inject the molding material into the spiral flow mold. At this time, the mold temperature was 175 ° C., the injection pressure was 6.9 MPa, and the holding pressure time was 120 seconds. The amount of spiral flow was determined based on the ultimate length of the injected molding material and the like as described above.

Table 2 shows the obtained spiral flow amount.

2.2 Evaluation of resin exudation First, after the molding process by the low-pressure transfer molding machine performed in 2.1, the presence or absence of resin exuded on the upper part of the plunger was visually confirmed.

Next, the resin exudation was evaluated by comparing the confirmation results with the following evaluation criteria.

<Evaluation criteria for resin exudation>
◯: No resin is found on the upper part of the plunger Δ: A small amount of resin is found on the upper part of the plunger ×: A large amount of resin is found on the upper part of the plunger The above evaluation results are shown in Table 2.

2.3 Evaluation of magnetic characteristics The molding materials obtained in each Example and each Comparative Example were injection-molded using a low-pressure transfer molding machine at a mold temperature of 175 ° C., an injection pressure of 9.8 MPa, and a curing time of 120 seconds. A columnar molded product having a diameter of 16 mm and a height of 32 mm was obtained.

Then, the obtained molded product was post-cured at 175 ° C. for 4 hours to prepare a test piece.

Next, with respect to the obtained test piece, the relative magnetic permeability μ based on the maximum magnetic permeability was measured using an electromagnet type magnetizer and an AC / DC magnetization characteristic recorder (MTR-1488, manufactured by Metron Giken Co., Ltd.). The measurement results are shown in Table 2.

2.4 Evaluation of mechanical properties The molding materials obtained in each Example and each Comparative Example were injection-molded using a low-pressure transfer molding machine 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 width of 10 mm, a thickness of 4 mm, and a length of 80 mm was obtained.

Then, the obtained molded product was post-cured at 175 ° C. for 4 hours to prepare a test piece.

Then, the bending strength of the obtained test piece was measured. The measurement results are shown in Table 2.

2.5 Evaluation of glass transition temperature The molding materials obtained in each Example and each Comparative Example were injection-molded using a low-pressure transfer molding machine 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 size of 15 mm × 4 mm × 4 mm was obtained.

Then, the obtained molded product was post-cured at 175 ° C. for 4 hours to prepare a test piece.

Then, the obtained test piece was subjected to glass transition under the conditions of a measurement temperature range of 0 ° C. to 300 ° C. and a heating rate of 5 ° C./min using a thermomechanical analyzer (TMA100 manufactured by Seiko Instruments). The temperature Tg was measured. The measurement results are shown in Table 2.

As is clear from Table 2, it was confirmed that the molding materials obtained in each example had high fluidity and could suppress resin oozing.

Therefore, the moldability of the molding material is improved, and the filling property and uniformity of the magnetic material powder can be further improved, so that a molded product having good magnetic properties can be obtained, and the resin can be exuded. It was confirmed that by suppressing the generation of resin burrs and the like in the molded product, a molded product with few molding defects could be obtained.

1 Molding material 2 Resin 3 Magnetic powder 3a Iron-based particles 3b Fine particles 31 First particles 31'First particles 31S Surface 32 Second particles

Claims (6)

With resin
A magnetic powder containing iron-based particles exhibiting soft magnetism and having an iron content of 85% by mass or more, and fine particles exhibiting soft magnetism and having a particle size of 3 μm or less.
Have,
The iron-based particles include a first particle and a second particle whose constituent material composition is different from that of the first particle.
The average particle size of the first particles is 10 to 200 μm.
A molding material characterized in that the average particle size of the second particles is 1 to 100 μm smaller than the average particle size of the first particles . The molding material according to claim 1, wherein the iron-based particles and the fine particles have different constituent material compositions. The molding material according to claim 2, wherein the volume fraction of the fine particles is 3 to 25% by volume of the iron-based particles. The molding material according to any one of claims 1 to 3 , wherein the volume fraction of the iron-based particles is 50 to 90% by volume. A molded product, which is a cured product of the molding material according to any one of claims 1 to 4 . The molded product according to claim 5 , which has a relative magnetic permeability of 10 or more.

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