EP0289979A1 - Plastic magnets - Google Patents

Plastic magnets Download PDF

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Publication number
EP0289979A1
EP0289979A1 EP19880107032 EP88107032A EP0289979A1 EP 0289979 A1 EP0289979 A1 EP 0289979A1 EP 19880107032 EP19880107032 EP 19880107032 EP 88107032 A EP88107032 A EP 88107032A EP 0289979 A1 EP0289979 A1 EP 0289979A1
Authority
EP
European Patent Office
Prior art keywords
powder
plastic magnets
magnets
ferrite
plastic
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP19880107032
Other languages
German (de)
French (fr)
Inventor
Tadashi Sawafuji
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SAWAFUJI CO Ltd
Original Assignee
SAWAFUJI CO Ltd
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 SAWAFUJI CO Ltd filed Critical SAWAFUJI CO Ltd
Publication of EP0289979A1 publication Critical patent/EP0289979A1/en
Withdrawn legal-status Critical Current

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    • 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

Definitions

  • the present invention relates to plastic magnets and, in particular, to plastic magnets comprising two types of magnet powder (ie Nd-Fe-B group alloys and ferrite) in random desired ratios bonded by phenol resin.
  • magnets wherein magnet powders are bonded by resins such as those comprising Ba Ferrite or Sr Ferrite magnet powder bonded by resin or rare-earth magnet powder bonded by resin, have been conventionally known and such magnets are utilized in small motors, acoustic transducers. health instruments and the like.
  • the ferrite plastic magnets are priced low but have very low magnetic strength while the rare-earth alloy plastic magnets are highly priced while offering extremely powerful magnetic strength.
  • plastic magnets need to possess only as much magnetic strength as an application might require and need not be of extremely powerful magnetic strength at all instances.
  • plastic magnets are known to be of either low magnetic power or high magnetic power as described above.
  • the present invention has been researched in view of the above-mentioned problem points and, in other words, is to provide plastic magnets having the characteristics of composite moulded pieces comprising Nd-Fe-B group alloys powder, ferrite magnet powder and with phenol resin as the binder.
  • Nd-Fe-B group alloys used in the present invention indicate the alloys comprising not only Nd-Fe-B but also addition of a small amount of Co or other substances to the alloys.
  • Ferrite magnet powder herein employed may be welknown ferrite magnets comprising Fe203, NiO, CuO, ZnO and the like, Ba Ferrite magnet, Sr Ferrite magnet.
  • phenol resin binder wherein resins comprising phenols (phenol, cresol, resorcin) and aldehydes (formaldehyde, aceto-aldehyde, furfural) or de­natured resin thereof and where these may be prepared, for example, by having the phenol and formaldehyde react with acid or alkali as a catalyst.
  • resins comprising phenols (phenol, cresol, resorcin) and aldehydes (formaldehyde, aceto-aldehyde, furfural) or de­natured resin thereof and where these may be prepared, for example, by having the phenol and formaldehyde react with acid or alkali as a catalyst.
  • a phenol resin binder prevents the above-mentioned powders to disperse unevenly due to variance in the respective specific gravities.
  • the preliminary heating and drying treatment effects to form light resin costs on the surface of the powder particles resulting in granules of slightly viscous nature and while the granules may have variance in specific gravities, the movement thereof is thus limited making the magnets homogenous as long as the granules are mixed evenly.
  • the two types of magnet powder, Nd-Fe-B group alloys and ferrite, in random desired ratios are uniformly bonded with phenol resin, thereby enabling the production of plastic magnets of desired stages of magnetic power from low to intermediarly to powerful.
  • phenol resin binder has quaranteed ease of production, excellent thermal characteristics and mechanical strength of the products.
  • Ferrite powder of average particle size 5 ⁇ m comprising Fe203, MnO, ZnO and Nd-Fe-B group alloy powder of average particle size 200 ⁇ m are mixed in are ratio of 20:80 (by weight) respectively. 5 weight % of phenol resin monomer and 2 weight % of methanol are added thereto and the resulting mixture is kneaded, and subsequently heated and dried for 10 minutes at 100°C - 120°C.
  • the resulting granual mixture was heated and compression moulded at pressure 1000 kg/cm2, 160°C for about 5 minutes to obtain the moulded piece. De-gassing was effected once during the above process.
  • the moulded piece was magnetized by powerful magnetic field to obtain plastic magnet of homogeneous texture.
  • plastic magnets of varying ratios of the above­mentioned ferrite powder and Nd-Fe-B group alloy powder such as 30:70, 40:60, 80:20, 85:15 (weight) were produced in methods identical to the above-mentioned method.
  • magnetization was effected on moulded pieces obtained by thermal hardening, it is also possible to magnetize the pieces simultaneously to heating and compression moulding and thereby obtain plastic magnets (anisotropic) of greater magnetic power.
  • plastic magnets of the present invention comprise Nd-Fe-B group alloy and ferrite magnet mixed in random desired ratios and as such the present invention offers plastic magnets of low-intermediary-high magnetic power as desired.
  • phenol resin binder allows for plastic magnets of excellent thermal characteristic and tenacity and well suited for large motors and acoustic transducers.

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Hard Magnetic Materials (AREA)

Abstract

Plastic magnets comprising Nd-Fe-B group alloys powder, ferrite magnetic powder and phenol resin binding agent offering lower­intermediary-high magnetic power as desired.

Description

    BACKGROUND OF THE INVENTION Field of the Invention:
  • The present invention relates to plastic magnets and, in particular, to plastic magnets comprising two types of magnet powder (ie Nd-Fe-B group alloys and ferrite) in random desired ratios bonded by phenol resin.
    • Description of the Prior Art:
  • Various types of plastics magnets wherein magnet powders are bonded by resins such as those comprising Ba Ferrite or Sr Ferrite magnet powder bonded by resin or rare-earth magnet powder bonded by resin, have been conventionally known and such magnets are utilized in small motors, acoustic transducers. health instruments and the like.
  • Of the various above-mentioned plastic magnets, the ferrite plastic magnets are priced low but have very low magnetic strength while the rare-earth alloy plastic magnets are highly priced while offering extremely powerful magnetic strength.
  • It is a fact, however, that plastic magnets need to possess only as much magnetic strength as an application might require and need not be of extremely powerful magnetic strength at all instances.
  • Conventionally, however, plastic magnets are known to be of either low magnetic power or high magnetic power as described above.
    • Summary of the Invention:
  • The present invention has been researched in view of the above-mentioned problem points and, in other words, is to provide plastic magnets having the characteristics of composite moulded pieces comprising Nd-Fe-B group alloys powder, ferrite magnet powder and with phenol resin as the binder.
    • DETAILED DESCRIPTION OF THE INVENTION
  • Nd-Fe-B group alloys used in the present invention indicate the alloys comprising not only Nd-Fe-B but also addition of a small amount of Co or other substances to the alloys.
  • Ferrite magnet powder herein employed may be welknown ferrite magnets comprising Fe₂0₃, NiO, CuO, ZnO and the like, Ba Ferrite magnet, Sr Ferrite magnet.
  • For the resin binder, it is desirable to use phenol resin binder wherein resins comprising phenols (phenol, cresol, resorcin) and aldehydes (formaldehyde, aceto-aldehyde, furfural) or de­natured resin thereof and where these may be prepared, for example, by having the phenol and formaldehyde react with acid or alkali as a catalyst.
  • The use of a phenol resin binder prevents the above-mentioned powders to disperse unevenly due to variance in the respective specific gravities. In other words, the preliminary heating and drying treatment effects to form light resin costs on the surface of the powder particles resulting in granules of slightly viscous nature and while the granules may have variance in specific gravities, the movement thereof is thus limited making the magnets homogenous as long as the granules are mixed evenly.
  • The two types of magnet powder, Nd-Fe-B group alloys and ferrite, in random desired ratios are uniformly bonded with phenol resin, thereby enabling the production of plastic magnets of desired stages of magnetic power from low to intermediarly to powerful.
  • Moreover, the use of phenol resin binder has quaranteed ease of production, excellent thermal characteristics and mechanical strength of the products.
    • BRIEF DESCRIPTION OF THE DRAWINGS
    • Figs. 1 to 5 are the graphs showing respectively the magnetic characteristics in varying the ratios of Nd-Fe-B group alloys powder and ferrite powder such as 20:80, 30:70, 40:60, 80:20 and 85:15 (weight %), respectively.
    Examples:
  • The following gives a concrete discription of an example of a plastic magnet of the present invention.
  • Ferrite powder of average particle size 5µm comprising Fe₂0₃, MnO, ZnO and Nd-Fe-B group alloy powder of average particle size 200µm are mixed in are ratio of 20:80 (by weight) respectively. 5 weight % of phenol resin monomer and 2 weight % of methanol are added thereto and the resulting mixture is kneaded, and subsequently heated and dried for 10 minutes at 100°C - 120°C.
  • The resulting granual mixture was heated and compression moulded at pressure 1000 kg/cm², 160°C for about 5 minutes to obtain the moulded piece. De-gassing was effected once during the above process.
  • Subsequently, the moulded piece was magnetized by powerful magnetic field to obtain plastic magnet of homogeneous texture.
  • Furthermore, plastic magnets of varying ratios of the above­mentioned ferrite powder and Nd-Fe-B group alloy powder such as 30:70, 40:60, 80:20, 85:15 (weight) were produced in methods identical to the above-mentioned method.
  • The results thereof (BH max, Br, etc.) are given in Figs. 1 to 5.
  • While, in the example cited above, magnetization was effected on moulded pieces obtained by thermal hardening, it is also possible to magnetize the pieces simultaneously to heating and compression moulding and thereby obtain plastic magnets (anisotropic) of greater magnetic power.
  • As described in detail above plastic magnets of the present invention comprise Nd-Fe-B group alloy and ferrite magnet mixed in random desired ratios and as such the present invention offers plastic magnets of low-intermediary-high magnetic power as desired.
  • Moreover, the use of phenol resin binder allows for plastic magnets of excellent thermal characteristic and tenacity and well suited for large motors and acoustic transducers.

Claims (1)

  1. (1) Plastic magnets having the characteristics of a composite moulded pieces comprising Nd-Fe-B group alloys powder, ferrite magnet powder and phenol resin binding agent.
EP19880107032 1987-05-02 1988-05-02 Plastic magnets Withdrawn EP0289979A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP62109382A JPS63274114A (en) 1987-05-02 1987-05-02 Plastic magnet
JP109382/87 1987-05-02

Publications (1)

Publication Number Publication Date
EP0289979A1 true EP0289979A1 (en) 1988-11-09

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ID=14508822

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19880107032 Withdrawn EP0289979A1 (en) 1987-05-02 1988-05-02 Plastic magnets

Country Status (2)

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EP (1) EP0289979A1 (en)
JP (1) JPS63274114A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0375093A2 (en) * 1988-12-23 1990-06-27 Dresser Industries, Inc. Sensitive electrical to mechanical transducer
US5062981A (en) * 1989-06-27 1991-11-05 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Magnet and method for manufacturing the same
US5257639A (en) * 1988-12-23 1993-11-02 Dresser Industries, Inc. Electropneumatic positioner
WO2003017293A1 (en) * 2001-08-14 2003-02-27 General Electric Company Permanent magnet for electromagnetic device and method of making
US6652767B2 (en) * 2001-04-09 2003-11-25 Enplas Corporation Composition for plastic magnet
DE102019008033A1 (en) * 2019-11-20 2021-05-20 Forschungszentrum Jülich GmbH Arrangement of two-pole permanent magnets in an array and its use

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05284678A (en) * 1992-03-31 1993-10-29 Mabuchi Motor Co Ltd Miniature motor

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4022701A (en) * 1974-04-26 1977-05-10 Japan Special Steel Co., Ltd. High-performance anisotropic plastics magnet and a process for producing the same
US4184972A (en) * 1978-07-31 1980-01-22 Alexeevsky Vadim V Magnetodielectric material
DE3006736A1 (en) * 1979-02-23 1980-09-04 Inoue Japax Res METHOD AND DEVICE FOR PRODUCING AN ELASTOMERIC MAGNETIC OBJECT
US4308155A (en) * 1976-11-24 1981-12-29 Tdk Electronics Co., Ltd. Rubber or plastic magnet and magnetic powder for making the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4022701A (en) * 1974-04-26 1977-05-10 Japan Special Steel Co., Ltd. High-performance anisotropic plastics magnet and a process for producing the same
US4308155A (en) * 1976-11-24 1981-12-29 Tdk Electronics Co., Ltd. Rubber or plastic magnet and magnetic powder for making the same
US4184972A (en) * 1978-07-31 1980-01-22 Alexeevsky Vadim V Magnetodielectric material
DE3006736A1 (en) * 1979-02-23 1980-09-04 Inoue Japax Res METHOD AND DEVICE FOR PRODUCING AN ELASTOMERIC MAGNETIC OBJECT

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0375093A2 (en) * 1988-12-23 1990-06-27 Dresser Industries, Inc. Sensitive electrical to mechanical transducer
EP0375093A3 (en) * 1988-12-23 1991-12-18 Dresser Industries, Inc. Sensitive electrical to mechanical transducer
US5257639A (en) * 1988-12-23 1993-11-02 Dresser Industries, Inc. Electropneumatic positioner
US5062981A (en) * 1989-06-27 1991-11-05 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Magnet and method for manufacturing the same
US6652767B2 (en) * 2001-04-09 2003-11-25 Enplas Corporation Composition for plastic magnet
WO2003017293A1 (en) * 2001-08-14 2003-02-27 General Electric Company Permanent magnet for electromagnetic device and method of making
DE102019008033A1 (en) * 2019-11-20 2021-05-20 Forschungszentrum Jülich GmbH Arrangement of two-pole permanent magnets in an array and its use
WO2021098896A1 (en) * 2019-11-20 2021-05-27 Forschungszentrum Jülich GmbH Arrangement of bipolar permanent magnets to give an array and use thereof

Also Published As

Publication number Publication date
JPS63274114A (en) 1988-11-11

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