WO2013038791A1 - Compound for bonded magnets, and bonded magnet - Google Patents

Compound for bonded magnets, and bonded magnet Download PDF

Info

Publication number
WO2013038791A1
WO2013038791A1 PCT/JP2012/067881 JP2012067881W WO2013038791A1 WO 2013038791 A1 WO2013038791 A1 WO 2013038791A1 JP 2012067881 W JP2012067881 W JP 2012067881W WO 2013038791 A1 WO2013038791 A1 WO 2013038791A1
Authority
WO
WIPO (PCT)
Prior art keywords
resin
magnet
compound
bonded
magnet powder
Prior art date
Application number
PCT/JP2012/067881
Other languages
French (fr)
Japanese (ja)
Inventor
茂樹 柳田
中村　英樹
修弘 奥田
森　尚樹
Original Assignee
Tdk株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tdk株式会社 filed Critical Tdk株式会社
Publication of WO2013038791A1 publication Critical patent/WO2013038791A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/06—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/08—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H01F1/083—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together in a bonding agent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/02—Permanent magnets [PM]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0578—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together bonded together
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/10—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure
    • H01F1/11—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure in the form of particles
    • H01F1/113—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure in the form of particles in a bonding agent

Definitions

  • the present invention relates to a bonded magnet compound and a bonded magnet having sufficient heat resistance and excellent moldability.
  • the bonded magnet is manufactured by molding a compound (mixture) obtained by kneading magnet powder and an organic binder such as a thermoplastic resin or a thermosetting resin into a desired shape.
  • An injection molding method, a compression molding method, an extrusion molding method, or the like is used as a method for forming the bonded magnet.
  • the injection molding method is a method in which the above-mentioned compound is heated and melted, and the melt is injected into a mold to be molded into a desired shape. At this time, an anisotropic bonded magnet is formed if it is molded in a mold to which a magnetic field is applied, and an isotropic bonded magnet is formed if no magnetic field is applied.
  • the injection molding method has an advantage that the degree of freedom of shape is higher than that of the compression molding method and the extrusion molding method, and a product having a complicated shape can be easily molded.
  • a compound having a higher resin amount than that of the above-described two molding methods is required. For this reason, even if the same magnet powder is used, there is a drawback of low magnetic properties.
  • thermoplastic resin is generally used as an organic binder for bond magnets manufactured by injection molding. This is because when a thermosetting resin is used, there are problems such as poor moldability and the need for a curing treatment.
  • a thermoplastic resin used for the bond magnet a polyamide (Poly Amide, hereinafter referred to as PA) resin is well known. PA resin has good moldability and can reduce the amount of resin relatively, but is inferior in heat resistance, moisture resistance, and dimensional accuracy.
  • PPS polyphenylene sulfide
  • Patent Document 1 proposes a material having good moldability without impairing heat resistance by mixing PPS resin and PA resin at a predetermined ratio.
  • Patent Document 2 proposes and implements a bond magnet that uses PPS resin to prevent contact between adjacent magnet powders by covering the outer surface of the magnet powder with PPS resin and has excellent moldability and magnetic properties. Has been.
  • Patent Documents 3 to 5 in a bonded magnet or a compound for bonded magnet using a thermoplastic resin such as PPS resin, the surface of the magnet powder is treated with a coupling agent, so that the magnet powder and the resin material.
  • a method for improving the affinity and improving the dispersibility of the magnet powder and, as a result, improving the fluidity of the compound and improving the moldability has been proposed.
  • the content of PA12 (polylauryl lactam) resin in the resin component is required to be at least 30 vol%, which corresponds to about 4.2 wt% in terms of conversion. Since the melting point of PA12 resin is relatively low at about 175 ° C., when the content of PA12 resin is 30 vol% or more, it is said that the high heat resistance characteristic of PPS resin is sufficiently exhibited in actual use. hard. Moreover, since the PPS resin has a nonpolar molecular structure and the wettability to the magnet powder having a polar surface is poor, it is difficult to coat the magnet powder with the PPS resin. Therefore, as proposed and implemented in Patent Document 2, it is difficult to sufficiently prevent the magnetic powders from contacting each other by covering the outer surface of the magnetic powder with the PPS resin.
  • the magnetic powder is melted at a temperature higher than the melting point (about 280 ° C.) of the PPS resin necessary for compounding when the PPS resin is used.
  • the thermal decomposition and volatilization of the coupling agent component is likely to occur. Therefore, not only the original functions of improving the affinity between the magnetic powder and resin of the coupling agent and improving the dispersibility of the magnetic powder are not exhibited, but also due to the influence of the decomposition product of the coupling agent, Other unexpected problems may easily occur during kneading / molding, such as a decrease in fluidity / moldability.
  • the present invention has been made in view of the circumstances as described above, and has a sufficient heat resistance and is excellent by using a compound for a bonded magnet having excellent fluidity and filling properties at the time of molding and the compound.
  • An object of the present invention is to provide a bonded magnet that is heat resistant and excellent in dimensional accuracy, mechanical strength, and magnetic properties.
  • the compound for bonded magnet of the present invention includes magnet powder, polyphenylene sulfide (PPS) resin, and polyamide (PA) resin, and the content ratio of the magnet powder in the compound is The content ratio is 79 to 94.5 wt%, the content ratio of the PPS resin is 5 to 20 wt%, and the content ratio of the PA resin is 0.1 to 2 wt%.
  • the bonded magnet compound of the present invention includes magnet powder, polyphenylene sulfide (PPS) resin, and polyamide (PA) resin, the content ratio of the magnet powder in the compound is 81 to 93 wt%, and the content ratio of the PPS resin is It is characterized by being 6.5 to 18.5 wt% and the PA resin content ratio being 0.2 to 1.5 wt%.
  • PPS polyphenylene sulfide
  • PA polyamide
  • the magnet powder is coated with PA resin.
  • the PA resin is a PA resin synthesized by a polycondensation reaction between a diamine and a dicarboxylic acid.
  • the PA resin is characterized by containing an aromatic ring in its molecular skeleton.
  • the bonded magnet of the present invention includes magnet powder, PPS resin, and PA resin, the content ratio of magnet powder is 79 to 94.5 wt%, the content ratio of PPS resin is 5 to 20 wt%, and the content ratio of PA resin is It is characterized by 0.1 to 2 wt%.
  • the present invention it is possible to provide a compound for a bonded magnet that is excellent in fluidity and filling properties at the time of molding without impairing the heat resistance characteristic of the PPS resin.
  • the compound it is possible to provide a bonded magnet that can be used in a place where high heat resistance is required and is excellent in dimensional accuracy, mechanical strength, and magnetic characteristics.
  • FIG. 1 is a cross-sectional view of an essential part of an injection molding machine used for manufacturing a bonded magnet according to an embodiment of the present invention.
  • FIG. 2 is a cross-sectional view of a bonded magnet compound.
  • FIG. 3 is an enlarged view around the magnet powder in the bonded magnet compound of FIG.
  • FIG. 4 is a perspective view showing a preferred embodiment of the bonded magnet of the present invention.
  • the injection molding apparatus 1 shown in FIG. 1 will be described.
  • the injection molding apparatus 1 includes an extruder 3 having a hopper 2 into which pellets 5 are charged, and a mold 4 for molding a melt of the pellets 5 extruded from the extruder 3 in a cavity 6.
  • the injection molding apparatus 1 may include a coil for applying a magnetic field around the mold 4.
  • An anisotropic bonded magnet can be obtained if a magnetic field is applied during molding, and an isotropic bonded magnet can be obtained if molded without applying a magnetic field. In this embodiment, it is suitable in any case.
  • Magnet powder used in this embodiment is not particularly limited.
  • ferrite magnet powder Sm—Co magnet powder, Sm—Fe—N magnet powder, Nd—Fe—B magnet powder, or these And a mixture of magnet powders.
  • the ferrite magnet powder is preferably a hexagonal ferrite such as a magnetoplumbite type M phase or W phase.
  • a particularly preferred magnetoplumbite type M-phase ferrite is referred to as “M-type ferrite”, which is represented by the general formula AFe 12 O 19 (A is Sr, Ba, Ca, etc.).
  • the M-type ferrite further has rare earth elements, Ca, Pb, Si, Ga, Sn, Zn, In, Co, Ni, Ti, Cr, Mn, Cu, Ge, and Nb within a range that does not affect the deterioration of magnetic properties. , Zr, Al, B, etc. may be contained.
  • Sm—Co based magnet powder examples include SmCo 5 and Sm 2 Co 17 . These magnet powders include those in which a part of Co is substituted with a transition metal element such as Fe, Cu, or Zr within a range that does not affect the decrease in magnetic properties.
  • Sm—Fe—N magnet powder examples include Sm 2 Fe 17 N. These magnet powders include those in which a part of Fe is substituted with a transition metal element such as Co, Mn, Ni or the like within a range that does not affect the decrease in magnetic properties.
  • Nd—Fe—B magnet powder examples include Nd 2 Fe 14 B. These magnet powders are those in which a part of Nd is replaced with La, Ce, Pr, Tb, Dy, etc., and a part of Fe is a transition metal such as Co, Mn, Ni, etc., as long as the magnetic properties are not affected. Those substituted with an element, and those in which a part of B is substituted with C or the like are included.
  • Nd—Fe—B based magnet powder produced by HDDR (Hydrogenation-Disproportionation—Desorption-Recombination) method
  • HDDR Hydrogenation-Disproportionation—Desorption-Recombination
  • the average particle diameter of the magnet powder is not particularly limited, but is preferably about 0.1 to 200 ⁇ m, more preferably 1 to 100 ⁇ m.
  • the maximum particle size is preferably 300 ⁇ m or less, more preferably 250 ⁇ m or less.
  • compound density variation and fluidity variation occur, which may affect product deformation and characteristic variation, or cause galling in the kneader, molding machine and mold.
  • the particle size is small, the fluidity is lowered and the filling property at the time of molding is deteriorated, or when the magnet powder is a metal, it is easily oxidized and the magnetic properties are lowered.
  • the particle size distribution of the magnetic powder is not particularly limited, but if the distribution range is wide (particle size distribution is broad), the fluidity of the compound is improved and the filling property is improved even in a state where the amount of resin is small. Therefore, it is more preferable.
  • the content of the magnet powder in the compound is 79 to 94.5 wt%.
  • the amount of the magnet powder is preferably 81 to 93 wt%, more preferably 82 to 90 wt% with respect to the total amount of the compound.
  • thermoplastic resin is used as the organic binder.
  • various types of resins can be selected according to desired moldability, heat resistance, mechanical strength, etc., and even if one type of resin is used alone, two types of thermoplastic resins can be selected. You may mix and use the above resin.
  • the melting point of the thermoplastic resin component is preferably 200 to 400 ° C., more preferably 230 to 350 ° C.
  • the heat resistance in the present embodiment is insufficient.
  • the melting point exceeds 400 ° C., the load on the apparatus during kneading or molding becomes large, and since it is necessary to knead and mold at a high temperature, deterioration of the resin itself or magnet powder becomes a problem.
  • the shape as the organic binder raw material is not particularly limited, such as a powder shape, a bead shape, a pellet shape, etc., but a powder shape is more preferable for uniform mixing with the magnet powder.
  • thermoplastic resin PPS resin and PA resin are used as the thermoplastic resin.
  • PPS resin Polyphenylene sulfide (PPS) resin
  • a PPS resin is used.
  • the PPS resin is a thermoplastic resin having a molecular structure in which aromatic rings and sulfur atoms are alternately bonded, and has a high melting point of about 280 ° C., so that it is used in a field requiring high heat resistance.
  • the PPS resin acts as a main component of the organic binder of the magnet powder.
  • the PPS resin has a high melting point, so that it requires heat resistance, and since it has water resistance and oil resistance, it can be applied to parts used in environments that require these. Be expected.
  • PPS resin has a non-polar molecular structure, and its interaction with magnet powder is weak and difficult to wet. That is, since it is difficult for the magnetic powder to be covered with the PPS resin, the distance between the magnetic powders cannot be kept moderate, and the magnetic powders come into contact with each other. Therefore, it is difficult for the PPS resin alone to improve the fluidity and moldability of the compound and increase the content of the magnet powder.
  • PPS resins are classified into a straight-chain type and a crosslinked type based on the difference in molecular structure.
  • the type to be used is not limited, and a linear type or a cross-linked type may be used singly depending on the characteristics emphasized in the product, and both types are mixed in an arbitrary ratio. May be used.
  • the amount of PPS resin in this embodiment is 5 to 20 wt% with respect to the total amount of the compound. If it is less than 5 wt%, it is difficult to obtain the effect of heat resistance, which is a feature of PPS, and the fluidity of the compound is lowered, making molding difficult. On the other hand, if it exceeds 20 wt%, the resin component that easily flows and the magnet powder that does not easily flow are easily separated when the resin is melted, which adversely affects the fluidity and moldability of the compound. From this viewpoint, the amount of the PPS resin is more preferably 6.5 to 18.5 wt%, and further preferably 7 to 17 wt%.
  • PA resin is a thermoplastic resin having an amide bond (—CO—NH—) in the molecule.
  • PA resin is a thermoplastic resin having an amide bond (—CO—NH—) in the molecule.
  • aramid a thermoplastic resin having an amide bond (—CO—NH—) in the molecule.
  • the PA resin includes polyamide x and polyamide yz, and x, y, and z are numbers derived from the number of carbon atoms of the monomer component, respectively.
  • Polyamide x is obtained by ring-opening polymerization of cyclic lactam (carbon number x) or polycondensation of ⁇ -aminocarboxylic acid (carbon number x).
  • Polyamide yz is obtained by copolycondensation of diamine (carbon number y) and dicarboxylic acid (carbon number z).
  • diamine carbon number y
  • dicarboxylic acid carbon number z
  • either polyamide may be used singly or both types may be mixed and used in an arbitrary ratio depending on the characteristics emphasized in the product. Since it has a higher melting point, it is preferable to use polyamide yz.
  • polyamide x examples include PA6 (poly ( ⁇ -caprolactam)), PA11 (polyundecane lactam), PA12 (polylauryl lactam), and the like.
  • Polyamide yz includes PA66 (poly (hexamethylene adipamide)), PA610 (poly (hexamethylene sebamide)), PA46 (poly (tetramethylene adipamide), PA6T (poly (hexamethylene terephthalamide). )), PA9T (poly (nonamethylene terephthalamide)), PA6I (poly (hexamethylene isophthalamide)), poly (p-phenylene terephthalamide), poly (m-phenylene isophthalamide) and the like. Is not limited to these PA resins and may be appropriately selected within the scope of the present invention.
  • the PA resin includes an aliphatic PA whose main chain (molecular skeleton) is mainly composed of a carbon-carbon single bond and an aromatic PA whose main chain is mainly composed of an aromatic ring.
  • a semi-aromatic PA obtained by copolycondensation of an aliphatic monomer and an aromatic monomer.
  • the more aromatic rings are contained in the main chain of the PA molecule the higher the melting point, and the higher the heat resistance.
  • aliphatic PA, aromatic PA or semi-aromatic PA may be used singly or any type may be mixed and used at an arbitrary ratio, depending on the characteristics emphasized in the product. More preferably, semi-aromatic PA is used.
  • PA resins are classified into, for example, aliphatic PA is PA6, PA11, PA12, PA66, PA610, PA46, and aromatic PA is poly (p-phenylene terephthalamide), poly (m-phenyleneisophthalamide), Semi-aromatic PA is PA6T, PA9T, PA6I.
  • the PA resin acts as a subcomponent of the organic binder of the magnet powder.
  • the PA resin has various melting points depending on the molecular structure, and when the low melting point PA resin is a main component, the high heat resistance, which is a characteristic of the PPS resin, is impaired.
  • PA resin has an amide bond, which is a polar functional group, in the molecule, it can be expected to be easily attached due to interaction with the surface of the magnet powder. That is, the magnet powder is easily coated with PA resin, so that the distance between the magnet powders is kept moderate, the dispersion state of the magnet powder is improved and the frictional resistance is reduced, and the resin component and the magnet powder are integrated. Therefore, the fluidity and filling property of the compound at the time of molding can be enhanced, and the strength of the molded body and dimensional accuracy can be improved.
  • the amount of PA resin in this embodiment is 0.1 to 2 wt% with respect to the total amount of the compound. If it is less than 0.1 wt%, the dispersion state of the magnet powder in the organic binder is deteriorated, and the fluidity and filling property of the compound during molding are lowered. On the other hand, when it exceeds 2 wt%, when a low melting point PA resin of less than 200 ° C. is used, the PA resin is likely to be preferentially filled due to the fact that the PA resin is more fluid than the PPS resin. Therefore, the filling variation of the compound at the time of molding becomes large.
  • the amount of the PA resin is more preferably 0.2 to 1.5 wt%, and still more preferably 0.2 to 1.0 wt%, with respect to the total amount of the compound.
  • FIG. 2 shows a cross-sectional configuration diagram of the compound for bond magnet in the present embodiment
  • FIG. 3 shows an enlarged view around the magnet powder 7 in the compound for bond magnet of FIG.
  • the bonded magnet compound shown in FIGS. 2 and 3 is composed of magnet powder 7, PPS resin 9, and PA resin 8.
  • the PPS resin 9 has poor wettability to the magnet powder 7
  • the magnet powder 7 coated with the PA resin 8 is dispersed in the PPS resin 9.
  • a compound for bonded magnets can be provided.
  • the bonded magnet compound in this embodiment has a magnet powder content of 79 to 94.5 wt%, a PPS resin content of 5 to 20 wt%, and a PA resin content of 0.1 to 2 wt%. By making it within this range, it becomes a compound for bonded magnets with improved fluidity and filling properties at the time of molding without impairing the high heat resistance characteristic of PPS resin, and it is excellent in magnetic properties, dimensional accuracy, mechanical strength, etc. Bond magnets can be provided.
  • the bonded magnet compound in the present embodiment has a magnet powder content ratio of 82 wt% to 93 wt%, a PPS resin content ratio of 6.5 to 18.5 wt%, and PA
  • the resin content is preferably 0.2 to 1.5 wt%.
  • the weight ratio of the components contained in the compound for the bond magnet is, for example, TG-DTA (thermogravimetry-differential thermal analysis) method, FT-IR (Fourier transform infrared absorption spectrum) method, Py-GC-MS (pyrolysis). It can be confirmed by combining gas chromatography mass spectrometry) and the like. Since the compound for bonded magnets in this embodiment is composed of a plurality of components, it is very effective to combine a plurality of analysis methods. In the present invention, the analysis method is not limited to the above-described analysis method, and a component ratio may be obtained by combining appropriate analysis methods as necessary.
  • the PA resin coats the magnet powder
  • the thickness of the above-mentioned PA resin means that the PA resin has a linear molecular structure without bending, and all the molecules of the PA resin contained are layered on the surface of each magnet powder and uniformly adhered. This means the virtual thickness.
  • a schematic diagram thereof is shown in FIG. 2, and this hypothetical thickness T PA [nm] is the specific surface area S m [m 2 / g] and weight W m [g] of the magnet powder, and the density D PA [g of PA resin / Cm 3 ] and weight W PA [g].
  • T PA [(W PA / D PA ) / (S m ⁇ W m )] ⁇ 10 3 (1)
  • the PA resin is not completely coated on the surface of the magnet powder with a completely uniform thickness, and it is normal that the thickness of the PA resin varies among the magnet powders and within the magnet powder. . That is, in the present invention, the coating thickness of the PA resin is an average thickness when the surface of each of the magnet powders is covered with all of the PA resin contained therein, and this corresponds to the above-described virtual thickness. Therefore, the coating thickness of the PA resin can be obtained from the above formula (1), but can also be confirmed by an analysis method as described later.
  • the content of the PA resin is less than 5 nm, since the coating of the PA resin on the magnet powder becomes insufficient, the distance between the magnet powders cannot be kept moderate, and the magnet in the organic binder The dispersed state of the powder becomes worse, and the frictional resistance between the magnet powders increases. Therefore, the fluidity and fillability of the compound during molding are reduced.
  • the content of the PA resin exceeds 1300 nm, especially when a low melting point PA resin is used, the PA resin is preferentially filled due to the effect that the PA resin is more fluid than the PPS resin. Therefore, the filling variation of the compound at the time of molding increases. Further, the influence of moisture absorption of the PA resin cannot be ignored, and the magnet powder is oxidized and deteriorated or the fluidity of the compound is lowered.
  • the dispersion state of the magnetic powder in the bonded magnet compound in this embodiment, the coating state and coating thickness of the PA resin on the magnetic powder, for example, the cross section of the compound can be observed by SEM (scanning electron microscope, Scanning Electron Microscope) It can be confirmed by combining STEM (scanning transmission electron microscope, Scanning Transmission Electron Microscope) observation, element distribution analysis by EDS (Energy Dispersive X-ray Spectroscopy, Energy Dispersive X-ray Spectroscopy), and the like.
  • the analysis method is not limited to the above-described analysis method, and an appropriate analysis method may be combined as necessary.
  • additives such as an antioxidant and a heavy metal deactivator may be added as necessary.
  • the compound for bonded magnets of the present invention is exposed to a high temperature of about 300 ° C. during production, when using these additives, the amount used is minimized, or an additive having a high melting point or a high decomposition temperature is used. May be selected as appropriate.
  • FIG. 4 shows a preferred example of the bond magnet 10 in the present embodiment.
  • the form of the bonded magnet 10 shown in FIG. 4 is a ring (cylindrical) shape, but is not limited to this shape in the present invention.
  • the present invention can be applied to a bond magnet having a C shape.
  • the manufacturing method of the bonded magnet below, the manufacturing method of the bonded magnet which concerns on suitable embodiment of this invention is demonstrated.
  • the method for manufacturing a bonded magnet in the present embodiment includes a kneading / pellet preparation (compounding) step and a forming step, and a bonded magnet can be manufactured through the following steps. Each step will be described below.
  • Kneading / Pellet Making (Compounding) Step magnet powder, PPS resin, and PA resin are kneaded, and the kneaded product is formed into a pellet using a pelletizer or the like.
  • the kneading may be performed with, for example, a batch kneader or a twin screw extruder.
  • the pelletizer for example, a single screw extruder is used.
  • a twin screw extruder or the like is more preferable because pellets can be produced by continuously cutting a rod-like compound that is continuously discharged from a strand (discharge port) after kneading.
  • the kneading and pellet production are carried out with heating depending on the melting temperature of the PPS resin and PA resin to be used, and are preferably 250 to 350 ° C, more preferably 280 to 330 ° C.
  • the content of the magnet powder in the aforementioned compound is 79 to 94.5 wt%.
  • the amount of the magnet powder is preferably 82 to 93 wt%, more preferably 82 to 90 wt% with respect to the total amount of the compound.
  • the above-described pellet 5 is injection molded into the mold 4 to obtain a bonded magnet molded product.
  • the pellets 5 are heated and melted at, for example, 250 to 330 ° C. inside the extruder 3.
  • the mold 4 is closed and a cavity 6 is formed inside.
  • the heated melt is injected into the internal cavity 6 of the mold 4 by a screw and injection molded.
  • the temperature of the mold 4 at this time may be about 100 to 160 ° C.
  • the magnetic field applied to the mold 4 at this time may be about 398 to 1989 kA / m (5 to 25 kOe).
  • Examples 1 to 8, Comparative Examples 1 and 2 As magnet powder, anisotropic Nd—Fe—B magnet powder (average secondary particle size: 50 ⁇ m) prepared by HDDR method, as linear binder PPS resin (melting point: about 280 ° C.), PA6T (poly (Hexamethylene terephthalamide)) resin (melting point: about 300 ° C.) was prepared. These were weighed so as to have the compound composition shown in Table 1, and kneaded at 300 ° C. for 2 hr using a pressure heating kneader in which the inside of the cavity was replaced with nitrogen, and the resulting compound was pelletized with a pelletizer.
  • anisotropic Nd—Fe—B magnet powder (average secondary particle size: 50 ⁇ m) prepared by HDDR method, as linear binder PPS resin (melting point: about 280 ° C.), PA6T (poly (Hexamethylene terephthalamide)) resin (melting point: about 300 ° C.) was prepared. These
  • the obtained pellets were combined with a TG-DTA (thermogravimetry-differential thermal analysis) method, FT-IR (Fourier transform infrared absorption spectrum) method, Py-GC-MS (pyrolysis gas chromatograph mass spectrometry) method, The component ratio in the compound was confirmed.
  • the pellet 5 was injection molded into the mold 4 to produce an anisotropic bonded magnet.
  • the mold 4 Prior to injection into the mold 4, the mold 4 was closed, a cavity 6 was formed inside, and a magnetic field was applied to the mold 4.
  • the pellet 5 was heated and melted inside the extruder 3 and injected into the cavity 6 of the mold 4 by a screw.
  • the injection temperature was 300 ° C.
  • the mold temperature was 140 ° C.
  • the applied magnetic field during injection molding was 1592 kA / m.
  • the bonded magnet obtained in the magnetic field injection molding process was disk-shaped and had a diameter of 15 mm and a thickness of 10.5 mm.
  • the magnetic field application direction was the thickness direction.
  • the produced bonded magnet was subjected to density measurement by Archimedes method. Using this bond magnet, the magnetic properties (residual magnetic flux density Br, coercive force HcJ) were measured in a BH tracer with a maximum applied magnetic field of 1989 kA / m in the atmosphere at 25 ° C. The results are shown in Table 1.
  • a plate-like bonded magnet having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm was produced using the magnetic field injection molding apparatus 1 shown in FIG.
  • the magnetic field application direction was the thickness direction.
  • the deflection temperature under load was measured based on JIS K 7191 with a load at a bending stress of 1.8 MPa. The measurement results are indicated by “x” when the temperature is lower than 180 ° C., “ ⁇ ” when the temperature is 180 to 230 ° C., “ ⁇ ” when the temperature is 230 ° C. or higher, and “ ⁇ ” when the temperature is 250 ° C. or higher.
  • the bending strength was measured based on JIS K 7171 under the conditions of a distance between fulcrums of 64 mm and a load speed of 2 mm / mm.
  • the measurement results are indicated by “x” when the pressure is less than 60 MPa, “ ⁇ ” when the pressure is 60 to 90 MPa, “ ⁇ ” when the pressure is 90 MPa or more, and “ ⁇ ” when the pressure is 100 MPa or more.
  • Comparative Example 3 A compound and a bonded magnet were prepared and evaluated in the same manner as in Example 1 except that PA6T resin was not used as the organic binder. The results are shown in Table 1.
  • Example 9 A compound and a bonded magnet were prepared and evaluated in the same manner as in Example 1 except that a cross-linked PPS (melting point: about 280 ° C.) resin was used as the organic binder. The results are shown in Table 1.
  • Example 10 A compound and a bonded magnet were prepared and evaluated in the same manner as in Example 1 except that a linear PPS resin and a cross-linked PPS resin were mixed at a weight ratio of 1: 1 as the organic binder. The results are shown in Table 1.
  • Comparative Example 4 As magnet powder, anisotropic Nd—Fe—B magnet powder (average particle size: 50 ⁇ m) prepared by HDDR method, PPS resin (melting point: about 280 ° C.) as organic binder, and surface treatment agent for magnet powder A silane coupling agent (N-phenyl-3-aminopropyltrimethoxysilane) was prepared.
  • the silane coupling agent diluted with absolute ethanol was sprayed on the magnet powder by 1 wt%, and further dry-mixed. After mixing, it was dried at 100 ° C. to obtain a silane coupling agent-treated anisotropic Nd—Fe—B magnet powder.
  • Examples 11-12, Comparative Examples 5-6 A compound and bonded magnet were prepared and evaluated in the same manner as in Example 1 or Comparative Example 1 except that the anisotropic Nd—Fe—B magnet powder produced by the HDDR method had an average particle size of 10 ⁇ m or 100 ⁇ m. went. The results are shown in Table 1.
  • Example 13 Comparative Example 7 A compound and a bonded magnet were prepared and evaluated in the same manner as in Example 1 or Comparative Example 1 except that PA12 (polylauryl lactam) resin (melting point: about 175 ° C.) was used instead of PA6T resin.
  • PA12 polylauryl lactam
  • Examples 14 to 15 and Comparative Example 8 A compound and bonded magnet were prepared and evaluated in the same manner as in Example 1 or Comparative Example 1 except that PA66 (poly (hexamethylene adipamide)) resin (melting point: about 240 ° C.) was used instead of PA6T resin. went. The results are shown in Table 1.
  • Example 16 Comparative Example 9 A compound and a bonded magnet were prepared and evaluated in the same manner as in Example 1 or Comparative Example 1 except that the magnet powder was an isotropic Nd—Fe—B magnet powder (average particle size: 75 ⁇ m). . The results are shown in Table 1.
  • the MVR value that is an index of fluidity is improved in the compound according to the present invention, that is, the compound containing PA resin (Examples 1 to 3 and Comparative Example 3). This is because the magnet powder is coated with PA resin and dispersed in the PPS resin, and the frictional resistance due to contact between the magnet powders is greatly reduced.
  • Comparative Example 2 the fluidity is low although the magnetic powder is treated with the coupling agent. This is because the coupling agent was thermally decomposed by heat during kneading and molding, and the effect of improving the lubricity of the PPS resin and the magnet powder was lost.
  • the magnet powder having reduced frictional resistance is more uniformly dispersed in the compound, so that the magnet powder and the organic binder are uniformly filled in the mold during molding. . Therefore, the density of the produced bonded magnet is improved, and a high residual magnetic flux density is obtained.
  • the compound containing no PA resin in the comparative example is hard to flow as a result of the magnet powder and the organic binder being integrated, so that the mold is filled with a highly fluid organic binder. Therefore, the density of the formed bonded magnet is not improved, and the residual magnetic flux density is low.
  • the compound containing a relatively high melting point PA resin (Comparative Examples 7 and 8) is filled with a high fluidity PA resin in the mold at the time of molding. The residual magnetic flux density obtained is low.
  • the bonded magnet according to the present invention is excellent in bending strength and deflection temperature under load. This is because the contact point between the low-strength magnet powders is greatly reduced, the magnet powder is more uniformly dispersed, the density variation is small, and the PPS resin covers the whole, so the mechanical strength and heat resistance Is thought to have improved.
  • the evaluation result of either bending strength or deflection temperature under load is “x”, it was set as a comparative example.
  • the bonded magnet compound according to the present invention has good fluidity and filling properties during molding, and it is clear that the obtained bonded magnet is excellent in magnetic properties, heat resistance and mechanical strength. is there.
  • the bonded magnet compound according to the present invention can be used in places where high heat resistance is required, and is excellent in fluidity and filling properties during molding. Use of the bonded magnet compound according to the present invention is useful for bonded magnets having excellent magnetic properties, dimensional accuracy, and mechanical strength.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Hard Magnetic Materials (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)

Abstract

[Problem] To provide: a compound for bonded magnets, which has sufficient heat resistance, while exhibiting excellent fluidity and fillability during molding; and a bonded magnet. [Solution] A compound for bonded magnets, which is characterized by containing a magnet powder, a polyphenylene sulfide (PPS) resin and a polyamide (PA) resin, and having a magnet powder content in the compound of 79-94.5 wt%, a PPS resin content of 5-20 wt% and a PA resin content of 0.1-2 wt%; and a bonded magnet.

Description

ボンド磁石用コンパウンド、及び、ボンド磁石Compound for bonded magnet and bonded magnet
　本発明は、十分な耐熱性を有し、成形性に優れたボンド磁石用コンパウンド及びボンド磁石に関するものである。 The present invention relates to a bonded magnet compound and a bonded magnet having sufficient heat resistance and excellent moldability.
　ボンド磁石は、磁石粉末と熱可塑性樹脂や熱硬化性樹脂などの有機バインダーを混練して得られたコンパウンド（混合物）を、所望とする形状に成形して製造される。ボンド磁石の成形方法には、射出成形法、圧縮成形法、押出成形法などが利用されている。 The bonded magnet is manufactured by molding a compound (mixture) obtained by kneading magnet powder and an organic binder such as a thermoplastic resin or a thermosetting resin into a desired shape. An injection molding method, a compression molding method, an extrusion molding method, or the like is used as a method for forming the bonded magnet.
　射出成形法は、前述のコンパウンドを加熱溶融して金型内に溶融物を注入し、所望の形状に成形する方法である。このとき、磁場印加された金型内で成形されれば異方性ボンド磁石、磁場印加されなければ等方性ボンド磁石となる。射出成形法は、圧縮成形法や押出成形法と比較して形状自由度が高く、複雑形状の製品も成形し易いといった利点がある。しかし、加熱溶融したコンパウンドに高流動性が求められるため、前述の２種の成形法よりも高樹脂量のコンパウンドが必要となる。このため、同じ磁石粉末を使用しても低磁気特性となる欠点がある。 The injection molding method is a method in which the above-mentioned compound is heated and melted, and the melt is injected into a mold to be molded into a desired shape. At this time, an anisotropic bonded magnet is formed if it is molded in a mold to which a magnetic field is applied, and an isotropic bonded magnet is formed if no magnetic field is applied. The injection molding method has an advantage that the degree of freedom of shape is higher than that of the compression molding method and the extrusion molding method, and a product having a complicated shape can be easily molded. However, since high fluidity is required for the heated and melted compound, a compound having a higher resin amount than that of the above-described two molding methods is required. For this reason, even if the same magnet powder is used, there is a drawback of low magnetic properties.
　射出成形法で製造されるボンド磁石には、有機バインダーとして一般的に熱可塑性樹脂が使用される。これは熱硬化性樹脂を用いた場合、成形性が悪い、硬化処理が必要などの問題があるためである。ボンド磁石に使用される熱可塑性樹脂としては、ポリアミド（Ｐｏｌｙ　Ａｍｉｄｅ、以下ＰＡと記載）樹脂が良く知られている。ＰＡ樹脂は成形性が良好で、樹脂量を比較的少なくすることが可能であるが、耐熱性、耐湿性、寸法精度の面で劣っている。これに対して、十分な耐熱性を有する熱可塑性樹脂としてポリフェニレンスルフィド（Ｐｏｌｙ　Ｐｈｅｎｙｌｅｎｅ　Ｓｕｌｆｉｄｅ、以下ＰＰＳと記載）樹脂を使用したボンド磁石が知られているが、成形性の面でＰＡ樹脂に劣るため、樹脂量を少なくすることが難しい。そこで、ＰＰＳ樹脂の耐熱性を生かしつつ、成形性を改善する検討が行われている。 A thermoplastic resin is generally used as an organic binder for bond magnets manufactured by injection molding. This is because when a thermosetting resin is used, there are problems such as poor moldability and the need for a curing treatment. As a thermoplastic resin used for the bond magnet, a polyamide (Poly Amide, hereinafter referred to as PA) resin is well known. PA resin has good moldability and can reduce the amount of resin relatively, but is inferior in heat resistance, moisture resistance, and dimensional accuracy. On the other hand, bond magnets using polyphenylene sulfide (hereinafter referred to as PPS) resin are known as thermoplastic resins having sufficient heat resistance, but are inferior to PA resins in terms of moldability. It is difficult to reduce the amount of resin. Therefore, studies have been made to improve moldability while making use of the heat resistance of PPS resin.
　例えば特許文献１には、ＰＰＳ樹脂とＰＡ樹脂を所定の割合で混合することで、耐熱性を損なうことなく成形性の良好な材料が提案されている。また、特許文献２には、ＰＰＳ樹脂を用いて、磁石粉末の外面をＰＰＳ樹脂で覆うことで隣接する磁石粉末同士の接触を阻止し、成形性と磁気特性に優れたボンド磁石が提案、実施されている。 For example, Patent Document 1 proposes a material having good moldability without impairing heat resistance by mixing PPS resin and PA resin at a predetermined ratio. Patent Document 2 proposes and implements a bond magnet that uses PPS resin to prevent contact between adjacent magnet powders by covering the outer surface of the magnet powder with PPS resin and has excellent moldability and magnetic properties. Has been.
　さらに、特許文献３～５には、ＰＰＳ樹脂をはじめとした熱可塑性樹脂を用いたボンド磁石やボンド磁石用コンパウンドにおいて、磁石粉末の表面をカップリング剤処理することで、磁石粉末と樹脂材料の親和性を向上させ、磁石粉末の分散性を改善し、その結果、コンパウンドの流動性を向上して成形性を改善する方法が提案されている。 Further, in Patent Documents 3 to 5, in a bonded magnet or a compound for bonded magnet using a thermoplastic resin such as PPS resin, the surface of the magnet powder is treated with a coupling agent, so that the magnet powder and the resin material There has been proposed a method for improving the affinity and improving the dispersibility of the magnet powder and, as a result, improving the fluidity of the compound and improving the moldability.
特開平０３－１６７８０４号公報Japanese Patent Laid-Open No. 03-167804 特開平０９－２２３６１６号公報Japanese Patent Laid-Open No. 09-223616 特開昭６２－２２３２６８号公報JP-A-62-223268 特開昭６２－２８２４１８号公報JP-A-62-282418 特開平０６－２９５８１６号公報Japanese Patent Laid-Open No. 06-295816
　しかしながら、特許文献１の実施例によれば、樹脂成分中のＰＡ１２（ポリラウリルラクタム）樹脂の含有量が少なくとも３０ｖｏｌ％必要であり、これは換算すると約４．２ｗｔ％に相当する。ＰＡ１２樹脂の融点は１７５℃程度と比較的低温であるため、ＰＡ１２樹脂の含有量が３０ｖｏｌ％以上となった場合、ＰＰＳ樹脂の特徴である高耐熱性が実使用において十分発揮されるとはいい難い。また、ＰＰＳ樹脂は非極性の分子構造を有し、表面が極性を有する磁石粉末への濡れ性が悪いことから、磁石粉末をＰＰＳ樹脂で被覆しにくい。したがって、特許文献２に提案、実施されているように、磁石粉末の外面をＰＰＳ樹脂が覆って、磁石粉末同士の接触を十分に阻止するのは困難である。 However, according to the example of Patent Document 1, the content of PA12 (polylauryl lactam) resin in the resin component is required to be at least 30 vol%, which corresponds to about 4.2 wt% in terms of conversion. Since the melting point of PA12 resin is relatively low at about 175 ° C., when the content of PA12 resin is 30 vol% or more, it is said that the high heat resistance characteristic of PPS resin is sufficiently exhibited in actual use. hard. Moreover, since the PPS resin has a nonpolar molecular structure and the wettability to the magnet powder having a polar surface is poor, it is difficult to coat the magnet powder with the PPS resin. Therefore, as proposed and implemented in Patent Document 2, it is difficult to sufficiently prevent the magnetic powders from contacting each other by covering the outer surface of the magnetic powder with the PPS resin.
　さらに、特許文献３～５に提案されているような、磁石粉末をカップリング剤処理する方法では、ＰＰＳ樹脂を用いた場合のコンパウンド化に必要なＰＰＳ樹脂の融点（約２８０℃）以上で溶融混練した場合、カップリング剤成分の熱分解や揮発が起こりやすい。そのため、カップリング剤が有している磁石粉末と樹脂との親和性向上や、磁石粉末の分散性改善という本来の機能が発揮されないばかりか、カップリング剤の分解生成物の影響により、逆に流動性・成形性が低下するなど、混練・成形時に他の予期せぬ問題が発生することが容易に考えられる。 Further, in the method of treating magnetic powder with a coupling agent as proposed in Patent Documents 3 to 5, the magnetic powder is melted at a temperature higher than the melting point (about 280 ° C.) of the PPS resin necessary for compounding when the PPS resin is used. When kneaded, the thermal decomposition and volatilization of the coupling agent component is likely to occur. Therefore, not only the original functions of improving the affinity between the magnetic powder and resin of the coupling agent and improving the dispersibility of the magnetic powder are not exhibited, but also due to the influence of the decomposition product of the coupling agent, Other unexpected problems may easily occur during kneading / molding, such as a decrease in fluidity / moldability.
　そこで本発明は、前述のような事情に鑑みてなされたものであり、十分な耐熱性を有し、成形時の流動性・充填性に優れたボンド磁石用コンパウンド及び前記コンパウンドを用いることにより高耐熱性で、寸法精度、機械的強度、磁気特性に優れたボンド磁石を提供することを目的とする。 Therefore, the present invention has been made in view of the circumstances as described above, and has a sufficient heat resistance and is excellent by using a compound for a bonded magnet having excellent fluidity and filling properties at the time of molding and the compound. An object of the present invention is to provide a bonded magnet that is heat resistant and excellent in dimensional accuracy, mechanical strength, and magnetic properties.
　前述した課題を解決して目的を達成するために、本発明のボンド磁石用コンパウンドは、磁石粉末とポリフェニレンスルフィド（ＰＰＳ）樹脂とポリアミド（ＰＡ）樹脂を含み、コンパウンド中の磁石粉末の含有比率が７９～９４．５ｗｔ％、ＰＰＳ樹脂の含有比率が５～２０ｗｔ％、ＰＡ樹脂の含有比率が０．１～２ｗｔ％、であることを特徴とする。 In order to solve the above-described problems and achieve the object, the compound for bonded magnet of the present invention includes magnet powder, polyphenylene sulfide (PPS) resin, and polyamide (PA) resin, and the content ratio of the magnet powder in the compound is The content ratio is 79 to 94.5 wt%, the content ratio of the PPS resin is 5 to 20 wt%, and the content ratio of the PA resin is 0.1 to 2 wt%.
　好ましくは、本発明のボンド磁石用コンパウンドは、磁石粉末とポリフェニレンスルフィド（ＰＰＳ）樹脂とポリアミド（ＰＡ）樹脂を含み、コンパウンド中の磁石粉末の含有比率が８１～９３ｗｔ％、ＰＰＳ樹脂の含有比率が６．５～１８．５ｗｔ％、ＰＡ樹脂の含有比率が０．２～１．５ｗｔ％、であることを特徴とする。 Preferably, the bonded magnet compound of the present invention includes magnet powder, polyphenylene sulfide (PPS) resin, and polyamide (PA) resin, the content ratio of the magnet powder in the compound is 81 to 93 wt%, and the content ratio of the PPS resin is It is characterized by being 6.5 to 18.5 wt% and the PA resin content ratio being 0.2 to 1.5 wt%.
　好ましくは、磁石粉末がＰＡ樹脂に被覆されていることを特徴とする。 Preferably, the magnet powder is coated with PA resin.
　好ましくは、ＰＡ樹脂が、ジアミンとジカルボン酸との重縮合反応で合成されたＰＡ樹脂であることを特徴とする。 Preferably, the PA resin is a PA resin synthesized by a polycondensation reaction between a diamine and a dicarboxylic acid.
　好ましくは、ＰＡ樹脂が、その分子骨格中に芳香環を含んでいることを特徴とする。 Preferably, the PA resin is characterized by containing an aromatic ring in its molecular skeleton.
　また、本発明のボンド磁石は、磁石粉末とＰＰＳ樹脂とＰＡ樹脂を含み、磁石粉末の含有比率が７９～９４．５ｗｔ％、ＰＰＳ樹脂の含有比率が５～２０ｗｔ％、ＰＡ樹脂の含有比率が０．１～２ｗｔ％、であることを特徴とする。 The bonded magnet of the present invention includes magnet powder, PPS resin, and PA resin, the content ratio of magnet powder is 79 to 94.5 wt%, the content ratio of PPS resin is 5 to 20 wt%, and the content ratio of PA resin is It is characterized by 0.1 to 2 wt%.
　本発明によれば、ＰＰＳ樹脂の特徴である耐熱性を損なうことなく、成形時の流動性・充填性に優れたボンド磁石用コンパウンドを提供することが出来る。また前記コンパウンドを用いることにより、高耐熱性が必要な箇所に使用することが可能で、寸法精度、機械的強度や磁気特性に優れたボンド磁石を提供することが出来る。 According to the present invention, it is possible to provide a compound for a bonded magnet that is excellent in fluidity and filling properties at the time of molding without impairing the heat resistance characteristic of the PPS resin. In addition, by using the compound, it is possible to provide a bonded magnet that can be used in a place where high heat resistance is required and is excellent in dimensional accuracy, mechanical strength, and magnetic characteristics.
図１は、本発明の一実施形態に係るボンド磁石の製造に用いる、射出成形機の要部断面図である。FIG. 1 is a cross-sectional view of an essential part of an injection molding machine used for manufacturing a bonded magnet according to an embodiment of the present invention. 図２はボンド磁石用コンパウンドの断面構成図である。FIG. 2 is a cross-sectional view of a bonded magnet compound. 図３は、図２のボンド磁石用コンパウンド中の磁石粉末周囲の拡大図である。FIG. 3 is an enlarged view around the magnet powder in the bonded magnet compound of FIG. 図４は、本発明のボンド磁石の好適な実施形態を示す斜視図である。FIG. 4 is a perspective view showing a preferred embodiment of the bonded magnet of the present invention.
　以下、本発明の実施形態を説明する。 Hereinafter, embodiments of the present invention will be described.
射出成形装置
　図１に示す射出成形装置１について説明する。この射出成形装置１は、ペレット５が投入されるホッパ２を有する押出機３と、押出機３から押し出されたペレット５の溶融物をキャビティ６内で成形するための金型４とを有する。この射出成形装置１には、金型４の周囲に磁場印加のためのコイルなどを備えていても良い。成形時に磁場印加されれば異方性ボンド磁石、磁場印加されずに成形されれば等方性ボンド磁石が、それぞれ得られる。本実施形態においては、いずれの場合のおいても好適である。 Injection Molding Device The injection molding device 1 shown in FIG. 1 will be described. The injection molding apparatus 1 includes an extruder 3 having a hopper 2 into which pellets 5 are charged, and a mold 4 for molding a melt of the pellets 5 extruded from the extruder 3 in a cavity 6. The injection molding apparatus 1 may include a coil for applying a magnetic field around the mold 4. An anisotropic bonded magnet can be obtained if a magnetic field is applied during molding, and an isotropic bonded magnet can be obtained if molded without applying a magnetic field. In this embodiment, it is suitable in any case.
磁石粉末
　本実施形態に用いられる磁石粉末は特に限定されないが、例えば、フェライト系磁石粉末、Ｓｍ－Ｃｏ系磁石粉末、Ｓｍ－Ｆｅ－Ｎ系磁石粉末、Ｎｄ－Ｆｅ－Ｂ系磁石粉末、あるいはこれらの磁石粉末の混合物が挙げられる。 Magnet powder The magnet powder used in this embodiment is not particularly limited. For example, ferrite magnet powder, Sm—Co magnet powder, Sm—Fe—N magnet powder, Nd—Fe—B magnet powder, or these And a mixture of magnet powders.
　フェライト系磁石粉末としては、好ましくはマグネトプランバイト型のＭ相、Ｗ相等の六方晶系のフェライトが用いられる。特に好ましいマグネトプランバイト型のＭ相のフェライトを「Ｍ型フェライト」とするが、前記Ｍ型フェライトは一般式ＡＦｅ１２Ｏ１９　（Ａは、Ｓｒ、Ｂａ、Ｃａ等）で表わされる。このＭ型フェライトには更に、磁気特性の低下に影響しない範囲で、希土類元素、Ｃａ、Ｐｂ、Ｓｉ、Ｇａ、Ｓｎ、Ｚｎ、Ｉｎ、Ｃｏ、Ｎｉ、Ｔｉ、Ｃｒ、Ｍｎ、Ｃｕ、Ｇｅ、Ｎｂ、Ｚｒ、Ａｌ、Ｂ等が含有されていても良い。 The ferrite magnet powder is preferably a hexagonal ferrite such as a magnetoplumbite type M phase or W phase. A particularly preferred magnetoplumbite type M-phase ferrite is referred to as “M-type ferrite”, which is represented by the general formula AFe 12 O 19 (A is Sr, Ba, Ca, etc.). The M-type ferrite further has rare earth elements, Ca, Pb, Si, Ga, Sn, Zn, In, Co, Ni, Ti, Cr, Mn, Cu, Ge, and Nb within a range that does not affect the deterioration of magnetic properties. , Zr, Al, B, etc. may be contained.
　Ｓｍ－Ｃｏ系磁石粉末としては、例えば、ＳｍＣｏ５やＳｍ２Ｃｏ１７が挙げられる。これらの磁石粉末は、磁気特性低下に影響しない範囲でＣｏの一部がＦｅ、Ｃｕ、Ｚｒ等の遷移金属元素で置換されたものも含む。 Examples of the Sm—Co based magnet powder include SmCo 5 and Sm 2 Co 17 . These magnet powders include those in which a part of Co is substituted with a transition metal element such as Fe, Cu, or Zr within a range that does not affect the decrease in magnetic properties.
　Ｓｍ－Ｆｅ－Ｎ系磁石粉末としては、例えば、Ｓｍ２Ｆｅ１７Ｎが挙げられる。これらの磁石粉末は、磁気特性低下に影響しない範囲でＦｅの一部がＣｏ、Ｍｎ、Ｎｉ等の遷移金属元素で置換されたものも含む。 Examples of the Sm—Fe—N magnet powder include Sm 2 Fe 17 N. These magnet powders include those in which a part of Fe is substituted with a transition metal element such as Co, Mn, Ni or the like within a range that does not affect the decrease in magnetic properties.
　Ｎｄ－Ｆｅ－Ｂ系磁石粉末としては、例えば、Ｎｄ２Ｆｅ１４Ｂが挙げられる。これらの磁石粉末は、磁気特性低下に影響しない範囲で、Ｎｄの一部をＬａ、Ｃｅ、Ｐｒ、Ｔｂ、Ｄｙなどで置換されたもの、Ｆｅの一部をＣｏ、Ｍｎ、Ｎｉ等の遷移金属元素で置換されたもの、Ｂの一部をＣなどで置換されたものを含む。 Examples of the Nd—Fe—B magnet powder include Nd 2 Fe 14 B. These magnet powders are those in which a part of Nd is replaced with La, Ce, Pr, Tb, Dy, etc., and a part of Fe is a transition metal such as Co, Mn, Ni, etc., as long as the magnetic properties are not affected. Those substituted with an element, and those in which a part of B is substituted with C or the like are included.
　特にＮｄ－Ｆｅ－Ｂ系磁石粉末として、ＨＤＤＲ（水素化分解・脱水素再結合、Ｈｙｄｒｏｇｅｎａｔｉｏｎ－Ｄｉｓｐｒｏｐｏｒｔｉｏｎａｔｉｏｎ－Ｄｅｓｏｒｐｔｉｏｎ－Ｒｅｃｏｍｂｉｎａｔｉｏｎ）法で作製された異方性Ｎｄ－Ｆｅ－Ｂ系磁石粉末を使用すると、高磁気特性を有するボンド磁石を作製することが出来る。 In particular, when an anisotropic Nd—Fe—B based magnet powder produced by HDDR (Hydrogenation-Disproportionation—Desorption-Recombination) method is used as the Nd—Fe—B based magnet powder, A bonded magnet having high magnetic properties can be produced.
　磁石粉末の平均粒子径は、特に限定されるものではないが、０．１～２００μｍ程度が好ましく、より好ましくは１～１００μｍである。最大粒径は、３００μｍ以下が好ましく、より好ましくは２５０μｍ以下である。粒子サイズが大きいと、コンパウンドの密度バラツキや流動性バラツキを生じて製品の変形や特性バラツキに影響したり、混練機、成形機や金型内でカジリ発生の原因となる。逆に粒子サイズが小さいと、流動性が低下して成形時の充填性が悪化したり、磁石粉末が金属の場合には酸化しやすくなって磁気特性が低下する。 The average particle diameter of the magnet powder is not particularly limited, but is preferably about 0.1 to 200 μm, more preferably 1 to 100 μm. The maximum particle size is preferably 300 μm or less, more preferably 250 μm or less. When the particle size is large, compound density variation and fluidity variation occur, which may affect product deformation and characteristic variation, or cause galling in the kneader, molding machine and mold. On the other hand, if the particle size is small, the fluidity is lowered and the filling property at the time of molding is deteriorated, or when the magnet powder is a metal, it is easily oxidized and the magnetic properties are lowered.
　磁石粉末の粒径分布は、特に限定されるものではないが、分布の範囲が広い（粒径分布がブロード）と、樹脂量が少ない状態でもコンパウンドの流動性が向上し、充填性が改善されるため、より好ましい。 The particle size distribution of the magnetic powder is not particularly limited, but if the distribution range is wide (particle size distribution is broad), the fluidity of the compound is improved and the filling property is improved even in a state where the amount of resin is small. Therefore, it is more preferable.
　本実施形態において、コンパウンド中における磁石粉末の含有量は、７９～９４．５ｗｔ％である。磁石粉末の含有量がこの範囲内であることにより、十分な耐熱性を有し、成形時の高流動性・高充填性と高磁気特性が両立したボンド磁石用コンパウンドを製造することが出来る。このような観点から、磁石粉末の量は、コンパウンド総量に対して、好ましくは８１～９３ｗｔ％であり、更に好ましくは、８２～９０ｗｔ％である。 In this embodiment, the content of the magnet powder in the compound is 79 to 94.5 wt%. When the content of the magnet powder is within this range, it is possible to produce a compound for a bonded magnet that has sufficient heat resistance and has both high fluidity, high filling property and high magnetic properties during molding. From this point of view, the amount of the magnet powder is preferably 81 to 93 wt%, more preferably 82 to 90 wt% with respect to the total amount of the compound.
有機バインダー
　本実施形態では有機バインダーとして熱可塑性樹脂が用いられる。熱可塑性樹脂は、所望とする成形性、耐熱性、機械的強度などに応じて、様々な種類の樹脂を選択することが可能であり、１種類の樹脂を単独で使用しても、２種類以上の樹脂を混合して使用しても良い。 Organic Binder In this embodiment, a thermoplastic resin is used as the organic binder. As the thermoplastic resin, various types of resins can be selected according to desired moldability, heat resistance, mechanical strength, etc., and even if one type of resin is used alone, two types of thermoplastic resins can be selected. You may mix and use the above resin.
　本実施形態では、熱可塑性樹脂成分の融点として、２００～４００℃であることが好ましく、２３０～３５０℃であることがより好ましい。熱可塑性樹脂成分の融点が２００℃未満では、本実施形態における耐熱性が不十分である。また、融点が４００℃を超えると、混練時や成形時の装置負荷が大きくなったり、高温で混練、成形する必要があるために樹脂自体や磁石粉末の劣化が問題となる。また、有機バインダー原料としての形状は、粉末状、ビーズ形状、ペレット形状等、特に限定されないが、磁石粉末と均一に混合するためには粉末状であることがより好ましい。 In this embodiment, the melting point of the thermoplastic resin component is preferably 200 to 400 ° C., more preferably 230 to 350 ° C. When the melting point of the thermoplastic resin component is less than 200 ° C., the heat resistance in the present embodiment is insufficient. On the other hand, when the melting point exceeds 400 ° C., the load on the apparatus during kneading or molding becomes large, and since it is necessary to knead and mold at a high temperature, deterioration of the resin itself or magnet powder becomes a problem. Further, the shape as the organic binder raw material is not particularly limited, such as a powder shape, a bead shape, a pellet shape, etc., but a powder shape is more preferable for uniform mixing with the magnet powder.
　これらを鑑み、本実施形態では熱可塑性樹脂として、ＰＰＳ樹脂とＰＡ樹脂が用いられる。この２種類の樹脂を用いることで、十分な耐熱性を有し、成形性に優れたボンド磁石用コンパウンド及びボンド磁石を提供することが可能となる。 In view of these, in this embodiment, PPS resin and PA resin are used as the thermoplastic resin. By using these two types of resins, it is possible to provide a bonded magnet compound and a bonded magnet having sufficient heat resistance and excellent moldability.
ポリフェニレンスルフィド（ＰＰＳ）樹脂
　本実施形態ではＰＰＳ樹脂が用いられる。ＰＰＳ樹脂は、芳香環と硫黄原子が交互に結合した分子構造を有する熱可塑性樹脂で、約２８０℃の高融点であるため高耐熱性が必要な分野で利用されている。ＰＰＳ樹脂には直鎖型と架橋型の２種類があり、必要に応じて単独若しくは両方を任意の割合で混合して使用されている。 Polyphenylene sulfide (PPS) resin In this embodiment, a PPS resin is used. The PPS resin is a thermoplastic resin having a molecular structure in which aromatic rings and sulfur atoms are alternately bonded, and has a high melting point of about 280 ° C., so that it is used in a field requiring high heat resistance. There are two types of PPS resins, a straight-chain type and a cross-linked type, and they are used alone or in combination at any ratio as required.
　本実施形態において、ＰＰＳ樹脂は磁石粉末の有機バインダーの主成分として作用する。前述の通り、ＰＰＳ樹脂は高融点であることから耐熱性が必要とされる箇所や、また耐水性、耐油性を有することから、これらを必要とする環境下で使用される部品への応用が期待される。 In this embodiment, the PPS resin acts as a main component of the organic binder of the magnet powder. As described above, the PPS resin has a high melting point, so that it requires heat resistance, and since it has water resistance and oil resistance, it can be applied to parts used in environments that require these. Be expected.
　一方、ＰＰＳ樹脂は非極性の分子構造であり、磁石粉末との相互作用が弱く濡れにくい。すなわち、磁石粉末がＰＰＳ樹脂で被覆されにくいため、磁石粉末同士の間の距離を適度に保てず、磁石粉末同士が接触したりする。そのため、ＰＰＳ樹脂単独ではコンパウンドの流動性や成形性を向上したり、磁石粉末の含有率を高めたりすることが難しい。 On the other hand, PPS resin has a non-polar molecular structure, and its interaction with magnet powder is weak and difficult to wet. That is, since it is difficult for the magnetic powder to be covered with the PPS resin, the distance between the magnetic powders cannot be kept moderate, and the magnetic powders come into contact with each other. Therefore, it is difficult for the PPS resin alone to improve the fluidity and moldability of the compound and increase the content of the magnet powder.
　ＰＰＳ樹脂は、前述のように分子構造の違いから直鎖型と架橋型に分類される。本実施形態では、使用される型が限定されることはなく、製品で重視される特性に応じて、直鎖型または架橋型を単独で用いても良く、両方の型を任意の割合で混合して使用しても良い。 As described above, PPS resins are classified into a straight-chain type and a crosslinked type based on the difference in molecular structure. In the present embodiment, the type to be used is not limited, and a linear type or a cross-linked type may be used singly depending on the characteristics emphasized in the product, and both types are mixed in an arbitrary ratio. May be used.
　本実施形態におけるＰＰＳ樹脂の量は、コンパウンド総量に対して５～２０ｗｔ％である。５ｗｔ％未満であると、ＰＰＳの特徴である耐熱性という効果を得ることが困難でであるとともに、コンパウンドの流動性が低下して成形が困難となる。また、２０ｗｔ％を超えると、流動し易い樹脂成分と流動し難い磁石粉末が樹脂の溶融時に分離し易くなるため、コンパウンドの流動性や成形性に悪影響を及ぼすからである。こういった観点より、ＰＰＳ樹脂の量は、より好ましくは６．５～１８．５ｗｔ％であり、７～１７ｗｔ％であることが更に好ましい。 The amount of PPS resin in this embodiment is 5 to 20 wt% with respect to the total amount of the compound. If it is less than 5 wt%, it is difficult to obtain the effect of heat resistance, which is a feature of PPS, and the fluidity of the compound is lowered, making molding difficult. On the other hand, if it exceeds 20 wt%, the resin component that easily flows and the magnet powder that does not easily flow are easily separated when the resin is melted, which adversely affects the fluidity and moldability of the compound. From this viewpoint, the amount of the PPS resin is more preferably 6.5 to 18.5 wt%, and further preferably 7 to 17 wt%.
ポリアミド（ＰＡ）樹脂
　本実施形態ではＰＡ樹脂が用いられる。ＰＡ樹脂は、分子内にアミド結合（－ＣＯ－ＮＨ－）を有する熱可塑性樹脂であり、一般的には、主に脂肪族骨格で構成されているものはナイロン、芳香族骨格のみで構成されているものはアラミドと呼ばれている。ＰＡ樹脂には、ポリアミドｘとポリアミドｙｚが存在し、ｘ、ｙ、ｚは、それぞれモノマー成分の炭素数に由来する数字である。ポリアミドｘは、環状ラクタム（炭素数ｘ）の開環重合やω‐アミノカルボン酸（炭素数ｘ）の重縮合で得られる。ポリアミドｙｚは、ジアミン（炭素数ｙ）とジカルボン酸（炭素数ｚ）の共重縮合で得られる。なお、本実施形態では、製品で重視される特性に応じて、いずれのポリアミドを単独で用いても両方の型を任意の割合で混合して使用しても良いが、一般的にポリアミドｙｚの方が高融点であるため、ポリアミドｙｚを使用することが好ましい。 Polyamide (PA) resin In this embodiment, a PA resin is used. PA resin is a thermoplastic resin having an amide bond (—CO—NH—) in the molecule. Generally, what is mainly composed of an aliphatic skeleton is composed only of nylon and an aromatic skeleton. What is called is aramid. The PA resin includes polyamide x and polyamide yz, and x, y, and z are numbers derived from the number of carbon atoms of the monomer component, respectively. Polyamide x is obtained by ring-opening polymerization of cyclic lactam (carbon number x) or polycondensation of ω-aminocarboxylic acid (carbon number x). Polyamide yz is obtained by copolycondensation of diamine (carbon number y) and dicarboxylic acid (carbon number z). In this embodiment, either polyamide may be used singly or both types may be mixed and used in an arbitrary ratio depending on the characteristics emphasized in the product. Since it has a higher melting point, it is preferable to use polyamide yz.
　例えば、ポリアミドｘとしては、ＰＡ６（ポリ（ε―カプロラクタム））、ＰＡ１１（ポリウンデカンラクタム）、ＰＡ１２（ポリラウリルラクタム）などが挙げられる。また、ポリアミドｙｚとしては、ＰＡ６６（ポリ（ヘキサメチレンアジパミド））、ＰＡ６１０（ポリ（ヘキサメチレンセバサミド））、ＰＡ４６（ポリ（テトラメチレンアジパミド）、ＰＡ６Ｔ（ポリ（ヘキサメチレンテレフタルアミド））、ＰＡ９Ｔ（ポリ（ノナメチレンテレフタルアミド））、ＰＡ６Ｉ（ポリ（ヘキサメチレンイソフタルアミド））、ポリ（ｐ－フェニレンテレフタルアミド）、ポリ（ｍ－フェニレンイソフタルアミド）などが挙げられる。本実施形態においては、これらのＰＡ樹脂に限定されることなく、本発明の範囲内で必要に応じて適宜選択して良い。 For example, examples of polyamide x include PA6 (poly (ε-caprolactam)), PA11 (polyundecane lactam), PA12 (polylauryl lactam), and the like. Polyamide yz includes PA66 (poly (hexamethylene adipamide)), PA610 (poly (hexamethylene sebamide)), PA46 (poly (tetramethylene adipamide), PA6T (poly (hexamethylene terephthalamide). )), PA9T (poly (nonamethylene terephthalamide)), PA6I (poly (hexamethylene isophthalamide)), poly (p-phenylene terephthalamide), poly (m-phenylene isophthalamide) and the like. Is not limited to these PA resins and may be appropriately selected within the scope of the present invention.
　ＰＡ樹脂は、前述のように、主鎖（分子骨格）が主に炭素－炭素単結合で構成される脂肪族ＰＡと、主鎖が主に芳香環で構成される芳香族ＰＡがあり、また脂肪族系モノマーと芳香族系モノマーを共重縮合した半芳香族ＰＡも存在する。一般的に、ＰＡ分子の主鎖内に芳香環が多く含まれるほど高融点となり、耐熱性が向上する。本実施形態では、製品で重視される特性に応じて、脂肪族ＰＡ、芳香族ＰＡあるいは半芳香族ＰＡを単独で用いてもいずれの型を任意の割合で混合して使用しても良いが、半芳香族ＰＡを使用することがより好ましい。 As described above, the PA resin includes an aliphatic PA whose main chain (molecular skeleton) is mainly composed of a carbon-carbon single bond and an aromatic PA whose main chain is mainly composed of an aromatic ring. There is also a semi-aromatic PA obtained by copolycondensation of an aliphatic monomer and an aromatic monomer. In general, the more aromatic rings are contained in the main chain of the PA molecule, the higher the melting point, and the higher the heat resistance. In the present embodiment, aliphatic PA, aromatic PA or semi-aromatic PA may be used singly or any type may be mixed and used at an arbitrary ratio, depending on the characteristics emphasized in the product. More preferably, semi-aromatic PA is used.
　前述のＰＡ樹脂を分類すると、例えば、脂肪族ＰＡは、ＰＡ６、ＰＡ１１、ＰＡ１２、ＰＡ６６、ＰＡ６１０、ＰＡ４６、芳香族ＰＡは、ポリ（ｐ－フェニレンテレフタルアミド）、ポリ（ｍ－フェニレンイソフタルアミド）、半芳香族ＰＡはＰＡ６Ｔ、ＰＡ９Ｔ、ＰＡ６Ｉである。 The above PA resins are classified into, for example, aliphatic PA is PA6, PA11, PA12, PA66, PA610, PA46, and aromatic PA is poly (p-phenylene terephthalamide), poly (m-phenyleneisophthalamide), Semi-aromatic PA is PA6T, PA9T, PA6I.
　本実施形態でＰＡ樹脂は、磁石粉末の有機バインダーの副成分として作用する。ＰＡ樹脂は分子構造により様々な融点を有しており、低融点ＰＡ樹脂を主成分とした場合、ＰＰＳ樹脂の特徴である高耐熱性が損なわれるためである。ＰＡ樹脂は分子内に極性官能基であるアミド結合を有しているため、磁石粉末表面との相互作用により付着しやすいことが期待出来る。すなわち、磁石粉末がＰＡ樹脂で被覆されやすく、そのため磁石粉末同士の間の距離が適度に保たれ、磁石粉末の分散状態が向上して摩擦抵抗を低減すると共に、樹脂成分と磁石粉末が一体となって動くため、成形時のコンパウンドの流動性や充填性を高めることが出来る他、成形体強度や寸法精度の向上も期待出来る。 In this embodiment, the PA resin acts as a subcomponent of the organic binder of the magnet powder. This is because the PA resin has various melting points depending on the molecular structure, and when the low melting point PA resin is a main component, the high heat resistance, which is a characteristic of the PPS resin, is impaired. Since PA resin has an amide bond, which is a polar functional group, in the molecule, it can be expected to be easily attached due to interaction with the surface of the magnet powder. That is, the magnet powder is easily coated with PA resin, so that the distance between the magnet powders is kept moderate, the dispersion state of the magnet powder is improved and the frictional resistance is reduced, and the resin component and the magnet powder are integrated. Therefore, the fluidity and filling property of the compound at the time of molding can be enhanced, and the strength of the molded body and dimensional accuracy can be improved.
　本実施形態におけるＰＡ樹脂の量は、コンパウンド総量に対して０．１～２ｗｔ％である。０．１ｗｔ％未満であると、磁石粉末の有機バインダー中への分散状態が悪化し、成形時のコンパウンドの流動性や充填性が低下する。一方、２ｗｔ％を超えると、２００℃未満の低融点のＰＡ樹脂を使用していた場合には、ＰＡ樹脂がＰＰＳ樹脂よりも高流動性である影響により、ＰＡ樹脂が優先的に充填されやすくなるため、成形時のコンパウンドの充填バラツキが大きくなる。また、ＰＡ樹脂の吸湿の影響が大きくなり、磁石粉末が酸化劣化したり、コンパウンドの流動性が低下する。このような観点より、ＰＡ樹脂の量は、コンパウンド総量に対して、より好ましくは０．２～１．５ｗｔ％であり、０．２～１．０ｗｔ％であることが更に好ましい。 The amount of PA resin in this embodiment is 0.1 to 2 wt% with respect to the total amount of the compound. If it is less than 0.1 wt%, the dispersion state of the magnet powder in the organic binder is deteriorated, and the fluidity and filling property of the compound during molding are lowered. On the other hand, when it exceeds 2 wt%, when a low melting point PA resin of less than 200 ° C. is used, the PA resin is likely to be preferentially filled due to the fact that the PA resin is more fluid than the PPS resin. Therefore, the filling variation of the compound at the time of molding becomes large. Further, the effect of moisture absorption of the PA resin is increased, and the magnet powder is oxidized and deteriorated, and the fluidity of the compound is lowered. From such a viewpoint, the amount of the PA resin is more preferably 0.2 to 1.5 wt%, and still more preferably 0.2 to 1.0 wt%, with respect to the total amount of the compound.
ボンド磁石用コンパウンド
　図２に本実施形態におけるボンド磁石用コンパウンドの断面構成図を、図３に図２のボンド磁石用コンパウンド中の磁石粉末７周囲の拡大図を、それぞれ示す。図２および図３に示すボンド磁石用コンパウンドは、磁石粉末７とＰＰＳ樹脂９とＰＡ樹脂８から構成される。前述のように、ＰＰＳ樹脂９は磁石粉末７への濡れ性が悪いため、ＰＡ樹脂８で被覆した磁石粉末７をＰＰＳ樹脂９中に分散させる。このような構造を形成することにより、磁石粉末７同士の間の距離が適度に保たれることで、磁石粉末７の分散状態が向上して摩擦抵抗を低減するために、成形性に優れたボンド磁石用コンパウンドを提供することが出来る。 Compound for Bond Magnet FIG. 2 shows a cross-sectional configuration diagram of the compound for bond magnet in the present embodiment, and FIG. 3 shows an enlarged view around the magnet powder 7 in the compound for bond magnet of FIG. The bonded magnet compound shown in FIGS. 2 and 3 is composed of magnet powder 7, PPS resin 9, and PA resin 8. As described above, since the PPS resin 9 has poor wettability to the magnet powder 7, the magnet powder 7 coated with the PA resin 8 is dispersed in the PPS resin 9. By forming such a structure, the distance between the magnet powders 7 is kept moderate, so that the dispersion state of the magnet powders 7 is improved and the frictional resistance is reduced. A compound for bonded magnets can be provided.
　本実施形態におけるボンド磁石用コンパウンドは、磁石粉末の含有比率が７９～９４．５ｗｔ％、ＰＰＳ樹脂の含有比率が５～２０ｗｔ％、ＰＡ樹脂の含有比率が０．１～２ｗｔ％である。この範囲とすることで、ＰＰＳ樹脂の特徴である高耐熱性を損なうことなく、成形時の流動性や充填性を向上したボンド磁石用コンパウンドとなり、磁気特性、寸法精度や機械的強度などに優れたボンド磁石を提供することが出来る。このような観点から、本実施形態におけるボンド磁石用コンパウンドは、磁石粉末の含有比率が、８２ｗｔ％～９３ｗｔ％であり、ＰＰＳ樹脂の含有比率が、６．５～１８．５ｗｔ％であり、ＰＡ樹脂の含有比率が０．２～１．５ｗｔ％であることが好ましい。 The bonded magnet compound in this embodiment has a magnet powder content of 79 to 94.5 wt%, a PPS resin content of 5 to 20 wt%, and a PA resin content of 0.1 to 2 wt%. By making it within this range, it becomes a compound for bonded magnets with improved fluidity and filling properties at the time of molding without impairing the high heat resistance characteristic of PPS resin, and it is excellent in magnetic properties, dimensional accuracy, mechanical strength, etc. Bond magnets can be provided. From this point of view, the bonded magnet compound in the present embodiment has a magnet powder content ratio of 82 wt% to 93 wt%, a PPS resin content ratio of 6.5 to 18.5 wt%, and PA The resin content is preferably 0.2 to 1.5 wt%.
　ボンド磁石用コンパウンドに含まれる成分の重量比率は、例えば、ＴＧ－ＤＴＡ（熱重量測定―示差熱分析）法、ＦＴ－ＩＲ（フーリエ変換赤外吸収スペクトル）法、Ｐｙ－ＧＣ－ＭＳ（熱分解ガスクロマトグラフ質量分析）法、などを組合せることで確認することが出来る。本実施形態におけるボンド磁石用コンパウンドは、複数の成分から構成されているため、複数の分析手法を組み合わせることが非常に有効である。本発明では、前述の分析手法に制限されるものではなく、必要に応じて適切な分析手法を組み合わせて成分比率を求めて良い。 The weight ratio of the components contained in the compound for the bond magnet is, for example, TG-DTA (thermogravimetry-differential thermal analysis) method, FT-IR (Fourier transform infrared absorption spectrum) method, Py-GC-MS (pyrolysis). It can be confirmed by combining gas chromatography mass spectrometry) and the like. Since the compound for bonded magnets in this embodiment is composed of a plurality of components, it is very effective to combine a plurality of analysis methods. In the present invention, the analysis method is not limited to the above-described analysis method, and a component ratio may be obtained by combining appropriate analysis methods as necessary.
　ＰＡ樹脂が磁石粉末を被覆する際、その厚みが５～１３００ｎｍとなるようにＰＡ樹脂を含有することが好ましい。これは、コンパウンド中のＰＡ樹脂の含有比率を、前述の範囲にすることで達成される。ＰＡ樹脂は分子内に極性官能基を有することから、ＰＰＳ樹脂と比較して磁石粉末との親和性が高いため、磁石粉末と混練することでＰＡ樹脂が磁石粉末表面に被覆されやすい。 When the PA resin coats the magnet powder, it is preferable to contain the PA resin so that the thickness thereof is 5 to 1300 nm. This is achieved by setting the content ratio of the PA resin in the compound within the above-mentioned range. Since the PA resin has a polar functional group in the molecule, it has a higher affinity with the magnet powder than the PPS resin. Therefore, the PA resin is easily coated on the surface of the magnet powder by kneading with the magnet powder.
　ここで、前述のＰＡ樹脂の厚みとは、ＰＡ樹脂が屈曲なく直鎖状の分子構造になっており、磁石粉末それぞれの表面に、含有するＰＡ樹脂全ての分子が層状になって均一に付着している場合の仮想厚みを意味する。その模式図を図２に示しているが、この仮想厚みＴＰＡ［ｎｍ］は、磁石粉末の比表面積Ｓｍ［ｍ２／ｇ］と重量Ｗｍ［ｇ］、ＰＡ樹脂の密度ＤＰＡ［ｇ／ｃｍ３］と重量ＷＰＡ［ｇ］から下式（１）で求められる。
　　ＴＰＡ＝［（ＷＰＡ／ＤＰＡ）／（Ｓｍ×Ｗｍ）］×１０３　（１） Here, the thickness of the above-mentioned PA resin means that the PA resin has a linear molecular structure without bending, and all the molecules of the PA resin contained are layered on the surface of each magnet powder and uniformly adhered. This means the virtual thickness. A schematic diagram thereof is shown in FIG. 2, and this hypothetical thickness T PA [nm] is the specific surface area S m [m 2 / g] and weight W m [g] of the magnet powder, and the density D PA [g of PA resin / Cm 3 ] and weight W PA [g].
T PA = [(W PA / D PA ) / (S m × W m )] × 10 3 (1)
　実際には、全ての磁石粉末表面にＰＡ樹脂が完全に均一な厚みで被覆することはなく、磁石粉末毎に、また磁石粉末内でもＰＡ樹脂の厚みバラツキを有しているのが通常である。すなわち、本発明においてＰＡ樹脂の被覆厚みとは、磁石粉末それぞれの表面に、含有するＰＡ樹脂全てが被覆したときの平均厚みであり、これは前述の仮想厚みと一致する。したがって、ＰＡ樹脂の被覆厚みは前述の式（１）から求められるが、後述のような分析手法でも確認することが出来る。 Actually, the PA resin is not completely coated on the surface of the magnet powder with a completely uniform thickness, and it is normal that the thickness of the PA resin varies among the magnet powders and within the magnet powder. . That is, in the present invention, the coating thickness of the PA resin is an average thickness when the surface of each of the magnet powders is covered with all of the PA resin contained therein, and this corresponds to the above-described virtual thickness. Therefore, the coating thickness of the PA resin can be obtained from the above formula (1), but can also be confirmed by an analysis method as described later.
　５ｎｍ未満となるようなＰＡ樹脂の含有量である場合、磁石粉末へのＰＡ樹脂の被覆が不十分となるため、磁石粉末同士の間の距離が適度に保てず、有機バインダー中への磁石粉末の分散状態が悪くなったり、磁石粉末同士の摩擦抵抗が増大する。そのため、成形時のコンパウンドの流動性や充填性が低下する。一方、１３００ｎｍを超えるＰＡ樹脂の含有量である場合、特に低融点ＰＡ樹脂を使用していた場合には、ＰＡ樹脂がＰＰＳ樹脂よりも高流動性である影響により、ＰＡ樹脂が優先的に充填されやすくなるため、成形時のコンパウンドの充填バラツキが大きくなる。また、ＰＡ樹脂の吸湿の影響が無視出来なくなり、磁石粉末が酸化劣化したりコンパウンドの流動性が低下する。 When the content of the PA resin is less than 5 nm, since the coating of the PA resin on the magnet powder becomes insufficient, the distance between the magnet powders cannot be kept moderate, and the magnet in the organic binder The dispersed state of the powder becomes worse, and the frictional resistance between the magnet powders increases. Therefore, the fluidity and fillability of the compound during molding are reduced. On the other hand, when the content of the PA resin exceeds 1300 nm, especially when a low melting point PA resin is used, the PA resin is preferentially filled due to the effect that the PA resin is more fluid than the PPS resin. Therefore, the filling variation of the compound at the time of molding increases. Further, the influence of moisture absorption of the PA resin cannot be ignored, and the magnet powder is oxidized and deteriorated or the fluidity of the compound is lowered.
　本実施形態におけるボンド磁石用コンパウンド中における磁石粉末の分散状態や、磁石粉末へのＰＡ樹脂の被覆状態や被覆厚みは、例えば、コンパウンドの断面をＳＥＭ（走査型電子顕微鏡、Ｓｃａｎｎｉｎｇ　Ｅｌｅｃｔｒｏｎ　Ｍｉｃｒｏｓｃｏｐｅ）観察やＳＴＥＭ（走査型透過電子顕微鏡、Ｓｃａｎｎｉｎｇ　Ｔｒａｎｓｍｉｓｓｉｏｎ　Ｅｌｅｃｔｒｏｎ　Ｍｉｃｒｏｓｃｏｐｅ）観察、ＥＤＳ（エネルギー分散型Ｘ線分光法、Ｅｎｅｒｇｙ　Ｄｉｓｐｅｒｓｉｖｅ　Ｘ－ｒａｙ　Ｓｐｅｃｔｒｏｓｃｏｐｙ）による元素分布解析等を組み合わせることで、確認することが出来る。本発明では、前述の分析手法に制限されるものではなく、必要に応じて適切な分析手法を組み合わせて良い。 The dispersion state of the magnetic powder in the bonded magnet compound in this embodiment, the coating state and coating thickness of the PA resin on the magnetic powder, for example, the cross section of the compound can be observed by SEM (scanning electron microscope, Scanning Electron Microscope) It can be confirmed by combining STEM (scanning transmission electron microscope, Scanning Transmission Electron Microscope) observation, element distribution analysis by EDS (Energy Dispersive X-ray Spectroscopy, Energy Dispersive X-ray Spectroscopy), and the like. In the present invention, the analysis method is not limited to the above-described analysis method, and an appropriate analysis method may be combined as necessary.
　本発明のボンド磁石用コンパウンドには、必要に応じて酸化防止剤、重金属不活性化剤等の添加剤を添加しても良い。ただし、本発明のボンド磁石用コンパウンドにおいては、製造中に３００℃前後の高温に晒されるため、これら添加剤の使用時には、使用量を必要最小限にしたり、高融点あるいは高分解温度の添加剤を適宜選択すれば良い。 In the bonded magnet compound of the present invention, additives such as an antioxidant and a heavy metal deactivator may be added as necessary. However, since the compound for bonded magnets of the present invention is exposed to a high temperature of about 300 ° C. during production, when using these additives, the amount used is minimized, or an additive having a high melting point or a high decomposition temperature is used. May be selected as appropriate.
ボンド磁石
　図４に、本実施形態におけるボンド磁石１０の好適な一例を示す。図４に示すボンド磁石１０の形態は、リング（円筒）形状であるが、本発明ではこの形状に限定されるものではなく、金型を変えることによって、所望の形状（例えば、柱状、平板状又はＣ型形状）を有するボンド磁石に適用可能である。 Bond Magnet FIG. 4 shows a preferred example of the bond magnet 10 in the present embodiment. The form of the bonded magnet 10 shown in FIG. 4 is a ring (cylindrical) shape, but is not limited to this shape in the present invention. Alternatively, the present invention can be applied to a bond magnet having a C shape.
ボンド磁石の製造方法
　以下に、本発明の好適な実施形態に係るボンド磁石の製造方法について説明する。本実施形態におけるボンド磁石の製造方法は、混練・ペレット作製（コンパウンド化）工程、成形工程を含み、これからの工程を経て、ボンド磁石を製造することが出来る。各工程について以下に説明する。 The manufacturing method of the bonded magnet Below, the manufacturing method of the bonded magnet which concerns on suitable embodiment of this invention is demonstrated. The method for manufacturing a bonded magnet in the present embodiment includes a kneading / pellet preparation (compounding) step and a forming step, and a bonded magnet can be manufactured through the following steps. Each step will be described below.
混練・ペレット作製（コンパウンド化）工程
　本実施形態における混練・ペレット作製工程では、磁石粉末とＰＰＳ樹脂とＰＡ樹脂を混練し、混練物をペレタイザなどでペレット状に成形する。混練は、例えばバッチ式ニーダー、二軸押出機などで行えば良い。ペレタイザとしては、例えば一軸押出機が用いられる。特に、二軸押出機などは、混練後にストランド（排出口）から連続的に排出される、棒状のコンパウンドを連続してカットすればペレットが作製出来るので、より好適である。混練およびペレット作製は、使用するＰＰＳ樹脂およびＰＡ樹脂の溶融温度に応じて加熱しながら実施されるが、２５０～３５０℃であることが好ましく、２８０～３３０℃であることがより好ましい。 Kneading / Pellet Making (Compounding) Step In the kneading / pellet making step in the present embodiment, magnet powder, PPS resin, and PA resin are kneaded, and the kneaded product is formed into a pellet using a pelletizer or the like. The kneading may be performed with, for example, a batch kneader or a twin screw extruder. As the pelletizer, for example, a single screw extruder is used. In particular, a twin screw extruder or the like is more preferable because pellets can be produced by continuously cutting a rod-like compound that is continuously discharged from a strand (discharge port) after kneading. The kneading and pellet production are carried out with heating depending on the melting temperature of the PPS resin and PA resin to be used, and are preferably 250 to 350 ° C, more preferably 280 to 330 ° C.
　本実施形態において、前述のコンパウンド中における磁石粉末の含有量は、７９～９４．５ｗｔ％である。磁石粉末の含有量がこの範囲内であることにより、十分な耐熱性を有し、成形時の高流動性・高充填性と高磁気特性が両立したボンド磁石用コンパウンドを製造することが出来る。このような観点から、磁石粉末の量は、コンパウンド総量に対して、好ましくは８２～９３ｗｔ％であり、更に好ましくは、８２～９０ｗｔ％である。 In this embodiment, the content of the magnet powder in the aforementioned compound is 79 to 94.5 wt%. When the content of the magnet powder is within this range, it is possible to produce a compound for a bonded magnet that has sufficient heat resistance and has both high fluidity, high filling property and high magnetic properties during molding. From this point of view, the amount of the magnet powder is preferably 82 to 93 wt%, more preferably 82 to 90 wt% with respect to the total amount of the compound.
成形工程
　本実施形態の成形工程では、例えば図１に示す射出成形装置１を用いて、前述のペレット５を金型４内に射出成形し、ボンド磁石の成形品が得られる。ペレット５は押出機３の内部で、例えば２５０～３３０℃に加熱溶融される。この加熱溶融物が金型４に射出される前に金型４は閉じられ、内部にキャビティ６が形成される。加熱溶融物はスクリューにより金型４の内部キャビティ６に射出され、射出成形される。このときの金型４の温度は１００～１６０℃程度とすれば良い。 Molding Step In the molding step of the present embodiment, for example, using the injection molding apparatus 1 shown in FIG. 1, the above-described pellet 5 is injection molded into the mold 4 to obtain a bonded magnet molded product. The pellets 5 are heated and melted at, for example, 250 to 330 ° C. inside the extruder 3. Before the heated melt is injected into the mold 4, the mold 4 is closed and a cavity 6 is formed inside. The heated melt is injected into the internal cavity 6 of the mold 4 by a screw and injection molded. The temperature of the mold 4 at this time may be about 100 to 160 ° C.
　成形時、金型４へ磁場が印加されると、異方性ボンド磁石が得られる。このときの金型４への印加磁場は、３９８～１９８９ｋＡ／ｍ（５～２５ｋＯｅ）程度とすれば良い。 When a magnetic field is applied to the mold 4 during molding, an anisotropic bonded magnet is obtained. The magnetic field applied to the mold 4 at this time may be about 398 to 1989 kA / m (5 to 25 kOe).
　以上、ボンド磁石の好適な製造方法について説明したが、本発明は、前述した実施形態に限定されるものではなく、本発明の範囲内で主々に改変することが出来る。 As mentioned above, although the suitable manufacturing method of the bond magnet was demonstrated, this invention is not limited to embodiment mentioned above, It can change mainly within the scope of the present invention.
　以下、本発明の内容を実施例により更に詳細に説明するが、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the content of the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.
実施例１～８、比較例１、２
　磁石粉末として、ＨＤＤＲ法で作製した異方性Ｎｄ－Ｆｅ－Ｂ系磁石粉末（平均二次粒子径：５０μｍ）、有機バインダーとして、直鎖型ＰＰＳ樹脂（融点：約２８０℃）、ＰＡ６Ｔ（ポリ（ヘキサメチレンテレフタルアミド））樹脂（融点：約３００℃）を準備した。これらを表１に示すコンパウンド組成となるように秤量し、キャビティー内を窒素置換した加圧加熱ニーダーを用いて、３００℃で２ｈｒ混練し、得られたコンパウンドをペレタイザでペレット化した。 Examples 1 to 8, Comparative Examples 1 and 2
As magnet powder, anisotropic Nd—Fe—B magnet powder (average secondary particle size: 50 μm) prepared by HDDR method, as linear binder PPS resin (melting point: about 280 ° C.), PA6T (poly (Hexamethylene terephthalamide)) resin (melting point: about 300 ° C.) was prepared. These were weighed so as to have the compound composition shown in Table 1, and kneaded at 300 ° C. for 2 hr using a pressure heating kneader in which the inside of the cavity was replaced with nitrogen, and the resulting compound was pelletized with a pelletizer.
　得られたペレットについて、メルトインデクサを用いて、設定温度：３３０℃、荷重：１０ｋｇ、余熱時間：３６０秒、インターバル：２５ｍｍの条件で、ＭＶＲ（メルトボリュームフローレート、単位：ｃｍ３／１０ｍｉｎ．）を測定した。その結果を表１に示す。 The resulting pellets, using a melt indexer, set temperature: 330 ° C., load: 10 kg, preheating time: 360 seconds, interval: under the condition of 25 mm, MVR (melt volume flow rate, the unit: cm 3 / 10min.) Was measured. The results are shown in Table 1.
　得られたペレットについて、ＴＧ－ＤＴＡ（熱重量測定―示差熱分析）法、ＦＴ－ＩＲ（フーリエ変換赤外吸収スペクトル）法、Ｐｙ－ＧＣ－ＭＳ（熱分解ガスクロマトグラフ質量分析）法を組合せ、コンパウンド中の成分比率を確認した。 The obtained pellets were combined with a TG-DTA (thermogravimetry-differential thermal analysis) method, FT-IR (Fourier transform infrared absorption spectrum) method, Py-GC-MS (pyrolysis gas chromatograph mass spectrometry) method, The component ratio in the compound was confirmed.
　次に、図１に示す磁場射出成形装置１を用いて、ペレット５を金型４内に射出成形し、異方性ボンド磁石を作製した。金型４への射出前に、金型４は閉じられ、内部にキャビティ６が形成され、金型４には磁場が印加された。なお、ペレット５は、押出機３の内部で加熱溶融され、スクリューにより金型４のキャビティ６内に射出された。射出温度は３００℃、金型温度は１４０℃、射出成形時の印加磁場は１５９２ｋＡ／ｍとした。磁場射出成形工程で得られたボンド磁石は円板状であり、直径１５ｍｍ、厚み１０．５ｍｍであった。なお、磁場印加方向は厚み方向とした。 Next, using the magnetic field injection molding apparatus 1 shown in FIG. 1, the pellet 5 was injection molded into the mold 4 to produce an anisotropic bonded magnet. Prior to injection into the mold 4, the mold 4 was closed, a cavity 6 was formed inside, and a magnetic field was applied to the mold 4. The pellet 5 was heated and melted inside the extruder 3 and injected into the cavity 6 of the mold 4 by a screw. The injection temperature was 300 ° C., the mold temperature was 140 ° C., and the applied magnetic field during injection molding was 1592 kA / m. The bonded magnet obtained in the magnetic field injection molding process was disk-shaped and had a diameter of 15 mm and a thickness of 10.5 mm. The magnetic field application direction was the thickness direction.
　作製したボンド磁石は、アルキメデス法により、密度測定を行った。このボンド磁石を用い、２５℃の大気中にて、最大印加磁場１９８９ｋＡ／ｍの
Ｂ－Ｈトレーサにて磁気特性（残留磁束密度Ｂｒ、保磁力ＨｃＪ）を測定した。その結果を表１に示す。 The produced bonded magnet was subjected to density measurement by Archimedes method. Using this bond magnet, the magnetic properties (residual magnetic flux density Br, coercive force HcJ) were measured in a BH tracer with a maximum applied magnetic field of 1989 kA / m in the atmosphere at 25 ° C. The results are shown in Table 1.
　さらに、図１の磁場射出成形装置１にて、長さ８０ｍｍ、幅１０ｍｍ、厚み４ｍｍの板状ボンド磁石を作製した。なお、磁場印加方向は、厚み方向とした。このボンド磁石を用いて、荷重たわみ温度を、ＪＩＳ　Ｋ　７１９１に基づいて、曲げ応力１．８ＭＰａとなる荷重で測定した。測定結果は、１８０℃未満の場合は「×」、１８０～２３０℃の場合は「△」、２３０℃以上の場合は「○」、２５０℃以上の場合は「◎」で、それぞれ示した。また、曲げ強度をＪＩＳ　Ｋ　７１７１に基づいて、支点間距離６４ｍｍ、加重速度２ｍｍ／ｍｍの条件で測定した。測定結果は、６０ＭＰａ未満の場合は「×」、６０～９０ＭＰａの場合は「△」、９０ＭＰａ以上の場合は「○」、１００ＭＰａ以上の場合は、「◎」で、それぞれ示した。 Further, a plate-like bonded magnet having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm was produced using the magnetic field injection molding apparatus 1 shown in FIG. The magnetic field application direction was the thickness direction. Using this bond magnet, the deflection temperature under load was measured based on JIS K 7191 with a load at a bending stress of 1.8 MPa. The measurement results are indicated by “x” when the temperature is lower than 180 ° C., “Δ” when the temperature is 180 to 230 ° C., “◯” when the temperature is 230 ° C. or higher, and “◎” when the temperature is 250 ° C. or higher. Further, the bending strength was measured based on JIS K 7171 under the conditions of a distance between fulcrums of 64 mm and a load speed of 2 mm / mm. The measurement results are indicated by “x” when the pressure is less than 60 MPa, “Δ” when the pressure is 60 to 90 MPa, “◯” when the pressure is 90 MPa or more, and “◎” when the pressure is 100 MPa or more.
　比較例３
　有機バインダーとして、ＰＡ６Ｔ樹脂を使用しない以外は、実施例１と同様にコンパウンド及びボンド磁石を作製し、評価を行った。その結果を表１に示す。 Comparative Example 3
A compound and a bonded magnet were prepared and evaluated in the same manner as in Example 1 except that PA6T resin was not used as the organic binder. The results are shown in Table 1.
　実施例９
　有機バインダーとして、架橋型ＰＰＳ（融点：約２８０℃）樹脂を用いた以外は、実施例１と同様にコンパウンド及びボンド磁石を作製し、評価を行った。その結果を表１に示す。 Example 9
A compound and a bonded magnet were prepared and evaluated in the same manner as in Example 1 except that a cross-linked PPS (melting point: about 280 ° C.) resin was used as the organic binder. The results are shown in Table 1.
　実施例１０
　有機バインダーとして、直鎖型ＰＰＳ樹脂と架橋型ＰＰＳ樹脂を重量比１：１で混合して用いた以外は、実施例１と同様にコンパウンド及びボンド磁石を作製し、評価を行った。その結果を表１に示す。 Example 10
A compound and a bonded magnet were prepared and evaluated in the same manner as in Example 1 except that a linear PPS resin and a cross-linked PPS resin were mixed at a weight ratio of 1: 1 as the organic binder. The results are shown in Table 1.
比較例４
　磁石粉末として、ＨＤＤＲ法で作製した異方性Ｎｄ－Ｆｅ－Ｂ系磁石粉末（平均粒子径：５０μｍ）、有機バインダーとしてＰＰＳ樹脂（融点：約２８０℃）、さらに磁石粉末への表面処理剤としてシランカップリング剤（Ｎ－フェニル－３－アミノプロピルトリメトキシシラン）を準備した。 Comparative Example 4
As magnet powder, anisotropic Nd—Fe—B magnet powder (average particle size: 50 μm) prepared by HDDR method, PPS resin (melting point: about 280 ° C.) as organic binder, and surface treatment agent for magnet powder A silane coupling agent (N-phenyl-3-aminopropyltrimethoxysilane) was prepared.
　ミキサーで異方性Ｎｄ－Ｆｅ－Ｂ系磁石粉末を乾式攪拌している中に、無水エタノールで希釈した前記シランカップリング剤を磁石粉末に対して１ｗｔ％噴霧し、さらに乾式混合した。混合後、１００℃で乾燥し、シランカップリング剤処理異方性Ｎｄ－Ｆｅ－Ｂ系磁石粉末を得た。 While the anisotropic Nd—Fe—B magnet powder was dry-stirred with a mixer, the silane coupling agent diluted with absolute ethanol was sprayed on the magnet powder by 1 wt%, and further dry-mixed. After mixing, it was dried at 100 ° C. to obtain a silane coupling agent-treated anisotropic Nd—Fe—B magnet powder.
　前記シランカップリング剤処理した磁石粉末を用いて、ＰＡ６Ｔ樹脂を使用しない以外は実施例１と同様にコンパウンド及びボンド磁石を作製し、評価を行った。その結果を表１に示す。 Using the magnet powder treated with the silane coupling agent, a compound and a bonded magnet were prepared and evaluated in the same manner as in Example 1 except that PA6T resin was not used. The results are shown in Table 1.
実施例１１～１２、比較例５～６
　ＨＤＤＲ法で作製した異方性Ｎｄ－Ｆｅ－Ｂ系磁石粉末の平均粒子径を１０μｍ、または１００μｍとした以外は、実施例１または比較例１と同様にコンパウンド及びボンド磁石を作製し、評価を行った。その結果を表１に示す。 Examples 11-12, Comparative Examples 5-6
A compound and bonded magnet were prepared and evaluated in the same manner as in Example 1 or Comparative Example 1 except that the anisotropic Nd—Fe—B magnet powder produced by the HDDR method had an average particle size of 10 μm or 100 μm. went. The results are shown in Table 1.
実施例１３、比較例７
　ＰＡ６Ｔ樹脂の代わりにＰＡ１２（ポリラウリルラクタム）樹脂（融点：約１７５℃）を使用した以外は、実施例１または比較例１と同様にコンパウンド及びボンド磁石を作製し、評価を行った。 Example 13, Comparative Example 7
A compound and a bonded magnet were prepared and evaluated in the same manner as in Example 1 or Comparative Example 1 except that PA12 (polylauryl lactam) resin (melting point: about 175 ° C.) was used instead of PA6T resin.
実施例１４～１５、比較例８
　ＰＡ６Ｔ樹脂の代わりにＰＡ６６（ポリ（ヘキサメチレンアジパミド））樹脂（融点：約２４０℃）を使用した以外は、実施例１または比較例１と同様にコンパウンド及びボンド磁石を作製し、評価を行った。その結果を表１に示す。 Examples 14 to 15 and Comparative Example 8
A compound and bonded magnet were prepared and evaluated in the same manner as in Example 1 or Comparative Example 1 except that PA66 (poly (hexamethylene adipamide)) resin (melting point: about 240 ° C.) was used instead of PA6T resin. went. The results are shown in Table 1.
　実施例１６、比較例９
　磁石粉末を、等方性Ｎｄ－Ｆｅ－Ｂ系磁石粉末（平均粒子径：７５μｍ）とした以外は、実施例１または比較例１と同様に、コンパウンド及びボンド磁石を作製し、評価を行った。その結果を表１に示す。 Example 16, Comparative Example 9
A compound and a bonded magnet were prepared and evaluated in the same manner as in Example 1 or Comparative Example 1 except that the magnet powder was an isotropic Nd—Fe—B magnet powder (average particle size: 75 μm). . The results are shown in Table 1.
実施例１７、比較例１０
　磁石粉末を、Ｍ型フェライト磁石粉末（主組成：Ｃａ０．４５Ｌａ０．４Ｓｒ０．１５Ｂａ０．００１Ｆｅ９．４Ｃｏ０．２５Ｏ１９、ＳｉＯ２＝０．６ｗｔ％含む、平均粒子径：１μｍ）とした以外は、実施例１または比較例１と同様にコンパウンド及びボンド磁石を作製し、評価を行った。その結果を表１に示す。 Example 17, Comparative Example 10
Magnet powder, M type ferrite magnet powder (main composition: Ca 0.45 La 0.4 Sr 0.15 Ba 0.001 Fe 9.4 Co 0.25 O 19 , SiO 2 = 0.6 wt%, average A compound and a bonded magnet were produced and evaluated in the same manner as in Example 1 or Comparative Example 1 except that the particle diameter was 1 μm. The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　同じ磁石粉末含有量で比較すると、本発明に係るコンパウンド、すなわちＰＡ樹脂を含むコンパウンドにおいて、流動性の指標であるＭＶＲ値が向上している（実施例１～３と比較例３など）。これは磁石粉末がＰＡ樹脂に被覆されてＰＰＳ樹脂中に分散し、磁石粉末同士の接触による摩擦抵抗が大きく低減されたためである。比較例２では、磁石粉末をカップリング剤処理したにも係わらず流動性が低い。これは混練・成形中の熱によりカップリング剤が熱分解し、ＰＰＳ樹脂と磁石粉末の潤滑性向上効果が失われたためである。また、ＰＡ樹脂を含むことで、磁石粉末含有量が多くなっても、高流動性を維持することが出来る（実施例２・４・５）。
　この流動性向上効果は、ＰＰＳ樹脂の種類が直鎖型であっても、架橋型であっても、両方の型が混合されていても、同様に確認出来た（実施例１・９・１０）。すなわち、ＰＰＳ樹脂の種類に係わらず、コンパウンド中の磁石粉末が同様の状態になっていると考えられる。 When compared with the same magnet powder content, the MVR value that is an index of fluidity is improved in the compound according to the present invention, that is, the compound containing PA resin (Examples 1 to 3 and Comparative Example 3). This is because the magnet powder is coated with PA resin and dispersed in the PPS resin, and the frictional resistance due to contact between the magnet powders is greatly reduced. In Comparative Example 2, the fluidity is low although the magnetic powder is treated with the coupling agent. This is because the coupling agent was thermally decomposed by heat during kneading and molding, and the effect of improving the lubricity of the PPS resin and the magnet powder was lost. Moreover, even if magnet powder content increases by containing PA resin, high fluidity | liquidity can be maintained (Example 2, 4, 5).
This fluidity improving effect could be confirmed in the same manner regardless of whether the type of PPS resin was a linear type, a crosslinked type, or a mixture of both types (Examples 1, 9, 10). ). That is, it is considered that the magnet powder in the compound is in the same state regardless of the type of PPS resin.
　このように本発明に係るコンパウンドは、コンパウンド中に摩擦抵抗が小さくなった磁石粉末がより均一に分散しているため、成形時において、金型中に磁石粉末と有機バインダーがムラなく充填される。そのため作製したボンド磁石の成形体密度が向上し、高い残留磁束密度が得られる。一方、比較例のＰＡ樹脂を含まないコンパウンドは、磁石粉末と有機バインダーが一体となって流動し難いため、流動性の高い有機バインダーが金型内に多く充填される。そのため作製したボンド磁石の成形体密度が向上せず、得られる残留磁束密度も低い。また、比較的低融点のＰＡ樹脂を多く含むコンパウンド（比較例７・８）は、成形時に高流動性のＰＡ樹脂が金型内に多く充填されてしまうため、作製したボンド磁石の成形体密度が向上せず、得られる残留磁束密度も低い。 As described above, in the compound according to the present invention, the magnet powder having reduced frictional resistance is more uniformly dispersed in the compound, so that the magnet powder and the organic binder are uniformly filled in the mold during molding. . Therefore, the density of the produced bonded magnet is improved, and a high residual magnetic flux density is obtained. On the other hand, the compound containing no PA resin in the comparative example is hard to flow as a result of the magnet powder and the organic binder being integrated, so that the mold is filled with a highly fluid organic binder. Therefore, the density of the formed bonded magnet is not improved, and the residual magnetic flux density is low. In addition, the compound containing a relatively high melting point PA resin (Comparative Examples 7 and 8) is filled with a high fluidity PA resin in the mold at the time of molding. The residual magnetic flux density obtained is low.
　比較例２のように、磁石粉末量が少なくＰＰＳ量が多い場合には、ＭＶＲ値自体は高いが、これは流動し易い樹脂成分と流動し難い磁石粉末が樹脂成分の溶融時に分離し易く、樹脂成分が多く流動した影響である。すなわち、成形時には樹脂成分が優先的に充填されてしまう。そのため、成形体密度が低下し、高い残留磁束密度、曲げ強度や荷重たわみ温度が得られない。
また、比較例３のように、磁石粉末量が多くＰＰＳ量が少ない場合、流動し易い樹脂成分自体が少なすぎてＭＶＲ値が大きく低下する。そのため、成形体を得ることが出来ないか、仮に成形出来たとしても、配向度低下による残留磁束密度の低下や密度バラツキによる強度低下の原因となる。 As in Comparative Example 2, when the amount of magnet powder is small and the amount of PPS is large, the MVR value itself is high, but this is easy to separate the resin component that flows easily and the magnet powder that does not flow easily when the resin component melts, This is the effect of a large amount of resin component flowing. That is, the resin component is preferentially filled during molding. For this reason, the density of the molded body is lowered, and a high residual magnetic flux density, bending strength and deflection temperature under load cannot be obtained.
Moreover, as in Comparative Example 3, when the amount of magnet powder is large and the amount of PPS is small, the resin component itself that tends to flow is too small and the MVR value is greatly reduced. Therefore, even if a molded body cannot be obtained or can be molded, it causes a decrease in residual magnetic flux density due to a decrease in orientation degree and a decrease in strength due to density variations.
　さらに、本発明に係るボンド磁石は、曲げ強度や荷重たわみ温度が優れている。これは、強度の低い磁石粉末同士の接触点が大きく低減され、磁石粉末がより均一に分散して密度バラツキが小さく、ＰＰＳ樹脂が全体を覆う形となっているため、機械的強度や耐熱性が向上したと考えられる。なお、本実施形態においては、曲げ強度もしくは荷重たわみ温度、いずれかの評価結果が「×」である場合に、比較例とした。 Furthermore, the bonded magnet according to the present invention is excellent in bending strength and deflection temperature under load. This is because the contact point between the low-strength magnet powders is greatly reduced, the magnet powder is more uniformly dispersed, the density variation is small, and the PPS resin covers the whole, so the mechanical strength and heat resistance Is thought to have improved. In the present embodiment, when the evaluation result of either bending strength or deflection temperature under load is “x”, it was set as a comparative example.
　以上のように、本発明に係るボンド磁石用コンパウンドは、成形時の流動性・充填性が良好で、得られたボンド磁石は磁気特性、耐熱性や機械的強度に優れていることが明確である。 As described above, the bonded magnet compound according to the present invention has good fluidity and filling properties during molding, and it is clear that the obtained bonded magnet is excellent in magnetic properties, heat resistance and mechanical strength. is there.
　本発明に係るボンド磁石用コンパウンドは、高耐熱性が必要な箇所に使用することが可能で、成形時の流動性・充填性に優れている。本発明に係るボンド磁石用コンパウンドを使用することは、磁気特性、寸法精度や機械的強度に優れたボンド磁石に有用である。 The bonded magnet compound according to the present invention can be used in places where high heat resistance is required, and is excellent in fluidity and filling properties during molding. Use of the bonded magnet compound according to the present invention is useful for bonded magnets having excellent magnetic properties, dimensional accuracy, and mechanical strength.
１　射出磁場成形装置
２　ホッパ
３　押出機
４　金型
５　ペレット
６　キャビティ
７　磁石磁粉
８　ＰＡ樹脂
９　ＰＰＳ樹脂
１０　ボンド磁石 DESCRIPTION OF SYMBOLS 1 Injection magnetic field shaping | molding apparatus 2 Hopper 3 Extruder 4 Mold 5 Pellet 6 Cavity 7 Magnet magnetic powder 8 PA resin 9 PPS resin 10 Bond magnet

Claims (6)

  1. ボンド磁石用コンパウンドであって、
    磁石粉末の含有比率が、７９～９４．５ｗｔ％であり、
    ポリフェニレンスルフィド樹脂の含有比率が、５～２０ｗｔ％であり、
    ポリアミド樹脂の含有比率が、０．１～２ｗｔ％
    であることを特徴とする、ボンド磁石用コンパウンド。　     Compound for bonded magnet,
    The content ratio of the magnet powder is 79-94.5 wt%,
    The content ratio of the polyphenylene sulfide resin is 5 to 20 wt%,
    Polyamide resin content is 0.1 to 2 wt%
    A compound for bonded magnets.
  2. 請求項１に記載のボンド磁石用コンパウンドであって、
    前記磁石粉末の含有比率が、８１～９３ｗｔ％であり、
    前記ポリフェニレンスルフィド樹脂の含有比率が、６．５～１８．５ｗｔ％であり、
    前記ポリアミド樹脂の含有比率が、０．２～１．５ｗｔ％
    であることを特徴とする、ボンド磁石用コンパウンド。     The bonded magnet compound according to claim 1,
    The content ratio of the magnet powder is 81 to 93 wt%,
    The content ratio of the polyphenylene sulfide resin is 6.5 to 18.5 wt%,
    The content ratio of the polyamide resin is 0.2 to 1.5 wt%
    A compound for bonded magnets.
  3. 請求項１のボンド磁石用コンパウンドであって、
    磁石粉末が、ポリアミド樹脂に被覆されていることを特徴とする、
    ボンド磁石用コンパウンド。     A bonded magnet compound according to claim 1,
    The magnet powder is coated with a polyamide resin,
    Compound for bonded magnet.
  4. 請求項１または請求項２のボンド磁石用コンパウンドであって、
    ポリアミド樹脂が、　ジアミンとジカルボン酸の重縮合反応物
    であることを特徴とする、ボンド磁石用コンパウンド。     A bonded magnet compound according to claim 1 or claim 2, wherein
    A bonded magnet compound, wherein the polyamide resin is a polycondensation reaction product of diamine and dicarboxylic acid.
  5. 請求項１乃至請求項３のボンド磁石用コンパウンドであって、
    ポリアミド樹脂が、その分子骨格中に芳香環を含むことを特徴とする、
    ボンド磁石用コンパウンド。     A bonded magnet compound according to claim 1 to claim 3, wherein
    The polyamide resin contains an aromatic ring in its molecular skeleton,
    Compound for bonded magnet.
  6. 磁石粉末の含有比率が、７９～９４．５ｗｔ％であり、
    ポリフェニレンスルフィド樹脂の含有比率が、５～２０ｗｔ％であり、
    ポリアミド樹脂の含有比率が、０．１～２ｗｔ％
    であることを特徴とする、ボンド磁石。     The content ratio of the magnet powder is 79-94.5 wt%,
    The content ratio of the polyphenylene sulfide resin is 5 to 20 wt%,
    Polyamide resin content is 0.1 to 2 wt%
    A bonded magnet, characterized in that
PCT/JP2012/067881 2011-09-17 2012-07-13 Compound for bonded magnets, and bonded magnet WO2013038791A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2011203865 2011-09-17
JP2011-203865 2011-09-17
JP2012-149252 2012-07-03
JP2012149252A JP5234207B2 (en) 2011-09-17 2012-07-03 Compound for bonded magnet and bonded magnet

Publications (1)

Publication Number Publication Date
WO2013038791A1 true WO2013038791A1 (en) 2013-03-21

Family

ID=47883033

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2012/067881 WO2013038791A1 (en) 2011-09-17 2012-07-13 Compound for bonded magnets, and bonded magnet

Country Status (2)

Country Link
JP (1) JP5234207B2 (en)
WO (1) WO2013038791A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6813941B2 (en) 2015-02-25 2021-01-13 Ｄｏｗａエレクトロニクス株式会社 Magnetic compounds, antennas and electronics
JP6552283B2 (en) 2015-06-02 2019-07-31 Ｄｏｗａエレクトロニクス株式会社 Magnetic compounds, antennas and electronic devices
JP6525742B2 (en) 2015-06-02 2019-06-05 Ｄｏｗａエレクトロニクス株式会社 Magnetic compound and antenna
TW202341192A (en) 2021-10-05 2023-10-16 日商戶田工業股份有限公司 Resin composition for bonded magnet and molded article using the same
WO2024057888A1 (en) * 2022-09-14 2024-03-21 戸田工業株式会社 Resin composition for bond magnet and bond magnet formed body formed using same

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6033285B2 (en) * 1979-12-20 1985-08-02 住友ベークライト株式会社 plastic magnet composition
JPH03167804A (en) * 1989-11-28 1991-07-19 Shin Kobe Electric Mach Co Ltd Molding material of resin magnet
WO1993023858A1 (en) * 1992-05-12 1993-11-25 Seiko Epson Corporation Rare earth bond magnet, composition therefor, and method of manufacturing the same
JP2003183702A (en) * 2001-12-18 2003-07-03 Aisin Seiki Co Ltd Soft magnetic powder material, soft magnetic molded article, and method for producing soft magnetic molded article
JP2004197212A (en) * 2002-10-21 2004-07-15 Aisin Seiki Co Ltd Soft magnetic molding, method of producing soft magnetic molding, and soft magnetic powder material

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6033285B2 (en) * 1979-12-20 1985-08-02 住友ベークライト株式会社 plastic magnet composition
JPH03167804A (en) * 1989-11-28 1991-07-19 Shin Kobe Electric Mach Co Ltd Molding material of resin magnet
WO1993023858A1 (en) * 1992-05-12 1993-11-25 Seiko Epson Corporation Rare earth bond magnet, composition therefor, and method of manufacturing the same
JP2003183702A (en) * 2001-12-18 2003-07-03 Aisin Seiki Co Ltd Soft magnetic powder material, soft magnetic molded article, and method for producing soft magnetic molded article
JP2004197212A (en) * 2002-10-21 2004-07-15 Aisin Seiki Co Ltd Soft magnetic molding, method of producing soft magnetic molding, and soft magnetic powder material

Also Published As

Publication number Publication date
JP2013077802A (en) 2013-04-25
JP5234207B2 (en) 2013-07-10

Similar Documents

Publication Publication Date Title
JP5234207B2 (en) Compound for bonded magnet and bonded magnet
KR100241982B1 (en) Rare earth bonded magnet and composition therefor
JP7435693B2 (en) Resin composition for melt molding, magnetic member, coil including magnetic member, method for manufacturing magnetic member
JP7518397B2 (en) Additives for bonded magnets and manufacturing method for compounds for bonded magnets
CN107615412B (en) Magnetic mixture and antenna
US20130265127A1 (en) Soft magnetic alloy powder, compact, powder magnetic core, and magnetic element
CN106751793A (en) High surface gloss high-dimensional stability polyamide compoiste material and preparation method thereof
Pigliaru et al. Poly-ether-ether-ketone–Neodymium-iron-boron bonded permanent magnets via fused filament fabrication
JP7502137B2 (en) Manufacturing method of bonded magnets and compounds for bonded magnets
US20070269332A1 (en) Method for Producing Composite Soft Magnetic Material Having High Strength and High Specific Resistance
WO2021065305A1 (en) Bonded magnet powder and bonded magnet
JP5948805B2 (en) Anisotropic bonded magnet and compound for anisotropic bonded magnet
TW202338003A (en) Resin composition for bonded magnet and molded magnet employing the same
JP6780693B2 (en) Manufacturing method of bond magnets and compounds for bond magnets
JP7060807B2 (en) Composition for bond magnet and its manufacturing method
JPS6190401A (en) Composition of plastic magnet
US20220380521A1 (en) Resin composition and molded article
JP4702396B2 (en) Bonded magnet composition and bonded magnet using the same
JP4412376B2 (en) Salt-water resistant magnet alloy powder, and resin composition for bond magnet, bond magnet or compacted magnet obtained by using the same
JP4501546B2 (en) Rare earth bonded magnet composition and rare earth bonded magnet obtained using the same
JP4126947B2 (en) Salt-resistant magnetic alloy powder, method for producing the same, resin composition for bonded magnet obtained by using the same, bonded magnet or compacted magnet
JP3864374B2 (en) Polyamide-based plastic magnetic material and magnet made therefrom
JP7409117B2 (en) Soft magnetic compound, its manufacturing method and bonded magnetic core
JP7156003B2 (en) Rare earth magnet manufacturing method and rare earth magnet
JP5159521B2 (en) Semi-rigid bonded magnet

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12831912

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12831912

Country of ref document: EP

Kind code of ref document: A1