JP2558790B2 - Resin magnet manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a resin magnet using a thermopolymerizable resin composition as a binder, and more specifically to microcapsules containing a thermopolymerizable resin component as an encapsulating substance. The present invention relates to a method for producing a resin magnet containing one or more of the above as a binder component.

Conventional technology As resin magnets with high magnetic performance, for example, Sm
(Co, Cu, Fe, M) n (where M is IV, V or VI of the periodic table)
Resin magnets are known that are one or a combination of two or more elements belonging to Group VII and Group VII, where n is generally an integer of 5 to 9) and are compression molded in a magnetic field with a binder of 2 to 6% by weight. .
As the binder for the resin magnet, an epoxy resin composition which is liquid at room temperature is generally adopted. Here, the epoxy resin composition is composed of an epoxy resin and a curing agent that three-dimensionally bridges it, or various additives such as a curing accelerator and a plasticizer that are added as necessary. It is known that such a binder, that is, an epoxy resin composition, has a significant influence on maintaining and ensuring the quality of resin magnets.

The epoxy resin is a general term for compounds having at least two oxirane rings in one molecule as represented by the following general formula.

However, Y in the above formula is a polyfunctional halohydrin, for example, a reaction product residue of epichlorohydrin and polyhydric phenol. Polyhydric phenols useful herein are resorcinol and various bisphenols obtained by condensation of phenol with aldehydes or ketones. Typical of these bisphenols are 2.2'-bis (P
-Hydroxyphenylpropane)
There are A, 4'4'-dihydroxybiphenyl, 4,4'-dihydroxyphenylmethane, 2.2'-dihydroxydiphenyl oxide and the like. Specifically, the most common epoxy resin is represented by the following general formula.

However, in the above formula, R is a saturated alkylene group having 1 to 8 carbon atoms,
A divalent group selected from oxygen and sulfonic groups, y
Is an integer of 0 or 25, and n is 0 or 1.

A condensate of epichlorohydrin and bisphenol A (DGEBA) can be particularly exemplified.

Next, as a curing agent for the epoxy resin as described above, for example, in the case of resin magnets, there are JP-A-60-37106 and JP-A-60-20730.
No. 2 discloses an azole compound having an amino group, which is specified as an imidazole represented by the following general formula.

However, in the above formula, R ₁ , R ₂ , R ₃ and R ₄ are individually selected from hydrogen, a lower alkyl group, a phenyl group and a lower alkylphenyl. For example imidazole, 2-ethyl-4-
Examples thereof include methyl imidazole, 1-benzyl-2-methyl imidazole, 1-methyl imidazole, 1.2-dimethyl imidazole.

However, imidazoles generally have a high melting point (typically 200
Since it is a solid (° C or higher), it is difficult to mix it with an epoxy resin, and the pot life of the epoxy resin composition is generally within 7 days. Moreover, the epoxy resin composition obtained by mixing the epoxy resin and the curing agent thereof is gradually polymerized to increase the viscosity. The increase in viscosity of the epoxy resin composition is the same even when mixed with a magnet material.
When a resin magnet such as (Co, Cu, Fe, M) n that generally requires magnetic anisotropy is manufactured, the degree of magnetic field orientation decreases due to the thickening of the epoxy resin composition, and for example, the residual magnetic flux of the resin magnet is reduced. The density will decrease depending on the degree of thickening. Finally, gelation occurs, and as a result, it becomes difficult to manufacture the resin magnet itself. In addition, Sm (Co, Cu, Fe, M)
When it is necessary to apply magnetic anisotropy like n, the epoxy resin composition is usually a liquid at room temperature in order to facilitate magnetic field orientation. Since the epoxy resin composition as the binder is liquid at room temperature as described above, it does not have fluidity as a powder molding material, and thus workability in forming a green body having an arbitrary shape is extremely difficult. Not only that, the mechanical strength of the green body itself is extremely low, so it was extremely difficult to secure quality and performance fibers. In order to overcome this drawback, many contrivances and proposals have been made regarding the form of the binder when molding the green body. For example, Japanese Patent Application Laid-Open No. 55-63808 discloses that a green body is formed by dry blending a magnet material and a fine powder thermopolymerizable resin. Although this method is effective for ensuring the quality of the green body, it requires a large amount of binder component to uniformly wet the surface of each magnet material with the fine powder thermopolymerizable resin when heating the green body. Therefore, the density of the magnetic material is reduced, and the magnetic performance is inevitably reduced. On the other hand, in JP-A-60-194509, a magnet material is coated with a thermopolymerizable resin composition which is solid at room temperature,
It is disclosed that a green body is molded at a temperature higher than the softening temperature of the thermopolymerizable resin composition, and the green body is released from the mold at a temperature lower than the softening temperature of the thermopolymerizable resin composition. . This method has a certain effect in maintaining and ensuring the quality and performance of the green body, but since it must be heated and cooled based on the softening temperature of the binder when molding the green body, a large amount of resin magnets are used industrially. There was an extremely difficult problem in terms of equipment maintenance for production.

Means for Solving the Problems The present invention has been made in view of the above background, and is a microcapsule having a thermopolymerizable resin component as an encapsulating substance.
One kind or two or more kinds are used as a binder component, and when the binder and the magnetic material are molded into a green body, some or all of the microcapsules are mechanically destroyed to elute the encapsulating substance of the capsules, and then the bonding is performed. It cures and cures the agent.

Action The present invention will be described in more detail below.

First, as the thermopolymerizable resin constituent referred to in the present invention, a typical epoxy resin composition as a binder for resin magnets can be exemplified. The constituent components of the epoxy resin composition here generally include an epoxy resin, a curing agent that three-dimensionally bridges the epoxy resin, and various additives that are added as necessary. Here, the epoxy resin is a generic term for compounds having at least two oxirane rings in at least one molecule. As the curing agent for the epoxy resin, aliphatic polyamines, polyamides,
Heterocyclic diamines, aromatic polyamines, acid anhydrides,
Any compound can be used as long as it is a compound capable of ring-opening polymerization of an oxirane ring, such as aromatic amine-containing fatty acid polyamines, imidazoles, dicyandiamide and its derivatives, organic acid hydrazide and its derivatives. Furthermore, a simple epoxy resin composition may be constituted with an epoxy resin and the above curing agent, and if necessary,
For example, various plasticizers such as monoepoxy compounds having one oxirane ring in one molecule and various curing accelerators such as tertiary amines can be added as constituent components.

Next, the microcapsules containing the thermopolymerizable resin component as an encapsulating substance in the present invention are produced by, for example, a so-called in-situ polymerization method in which suspension polymerization is performed in the presence of a liquid encapsulating substance at least at room temperature. be able to. Here, as the monomers generally used for forming the microcapsules, vinyl chloride, vinylidene chloride, acrylonitrile, styrene, vinyl acetate, methacrylic acid ester and various crosslinking agents can be exemplified. Used as a copolymer. The thermopolymerizable resin constituents used as the encapsulating material here are one or two or more kinds appropriately selected from an epoxy resin, a curing agent, and various additives added as necessary, and they are liquid at least at room temperature. In addition, the encapsulating material and the microcapsules must be chemically inert to each other. The microcapsules are preferably mononuclear spherical capsules having a particle size smaller than that of the magnet material.

Next, the magnet materials that can be used in the present invention include Sm (Co, Cu, F
e, M) n, Mo ・ nFe ₂ O ₃ (where M is one or more selected from the group of Ba, St, Pb, n is an integer of 4.5 to 6.2) Any of the particulate forms used can be used, particularly preferably Fe _100-xyz
Cox Ry Bz (where R is Nd or / and Pr, 0 ≦ x
≧ 30,10 ≦ y ≦ 28, 2 ≦ z ≦ 12, y + x ≦ 34,6z + y ≧ 34, where _x , _y , and _z represent the atomic% of Co, Nd, and B), and the magnetic anisotropy is shown. Fe having a particle size of several tens to several hundreds μm
It is a B-R type particle. However, such a Fe-BR magnet material may have a proper particle size after being subjected to a heat treatment of a thin piece produced by an ultra-quenching method such as a single roll method as disclosed in JP-A-59-6439. It is possible to use even a magnetically isotropic one as adjusted.
In addition, as long as the characteristics of the basic permanent magnet material are not impaired, the Fe-BR magnet material is made of, for example, Al, Si, Gu, Zn.
There is no problem even if other elements are mixed or regularly substituted.

As described above, at least one of the thermosetting resin components is used.
One or two or more kinds of microcapsules containing an encapsulating substance are used as the binder component of the resin magnet, and the combination thereof is a thermopolymerizable resin component which is solid at room temperature, a thermopolymerizable resin component which is liquid at room temperature, When a resin magnet is composed of a microcapsule containing a thermopolymerizable resin component that is liquid at room temperature as an encapsulating material, and a magnet material, [+++],
[++], [++], and [+] can be mentioned. However, when using, it is necessary to consider so as not to seriously affect the fluidity of the powder molding material and the mechanical strength of the green body, which is one of the important effects of the present invention.

The above combination, that is, a resin magnet material prepared by using a microcapsule containing at least one or more thermopolymerizable resin components as an encapsulating substance together with a magnet material as a binder component, is formed into a green body according to a conventional powder molding method. In that case, a magnetic field is applied as necessary. The mold for applying a magnetic field has a structure in which non-magnetic material yokes and magnetic material yokes are alternately combined so as to surround the cavity as necessary, and a magnetizing coil is arranged outside.
Alternatively, the magnetizing coil is embedded in the outer periphery of the cavity. In this method, a magnetizing coil is connected to a high voltage / low current type power source in order to generate a magnetic field having a predetermined strength in the cavity. Furthermore, a mold having a structure in which an alignment yoke having magnetic pole portions corresponding to predetermined positions around the cavity is installed and a conductive wire is provided in the yoke is used. Such a method energizes and energizes a conducting wire installed in the orientation yoke.Therefore, a commercial frequency AC power source is input and an instantaneous current power source that generates a pulse current by the all-thyristor full-wave phase control method, or a predetermined DC voltage. Boost rectified to
After charging the capacitor group, it is connected to the instantaneous DC power source that discharges through the thyristor. However, if the magnet material is magnetically isotropic, the mold having the above configuration is not necessary. In any case, the resin magnet material filled in the cavity is compressed to increase the density. At the stage of densification, the microcapsules are mechanically broken by the magnet material, and the thermopolymerizable resin constituents as the encapsulating substance are eluted. The thermopolymerizable resin constituents eluted from the microcapsules or the different thermopolymerizable resin constituents existing in advance outside the microcapsule system are densified (or the By mixing with each other in the (magnetic field orientation) stage, it becomes a usual thermopolymerizable resin composition, that is, a binder. Then, the fully densified green body is demagnetized and demolded in the cavity as needed. Further, after demolding, the thermopolymerizable resin composition, that is, the binder is polymerized and cured to obtain a resin magnet.

As described above, according to the method for producing a resin magnet of the present invention, it is easy to mix the binder, that is, the thermopolymerizable resin constituent component. In addition, since the chemically active components are separated by microcapsules even after mixing, they have good storage properties,
Thickening due to the polymerization reaction does not occur. Furthermore, the fluidity as a powder molding material is secured. Or, it has the advantages that it hardly interferes with the movement of the magnet material that requires magnetic field orientation, and that it does not require heating and cooling based on the softening temperature of the binder during molding of the green body. When manufacturing magnets, effective effects are maintained to maintain and secure quality and performance.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1. An alloy _{consisting of} Sm (Co _0.668 , Cu _0.101 , Fe _0.214 , Zr _0.017 ) _7.33 was solution treated at 1150 ° C for 24 hours and then 800 ° C.
Aging treatment was performed for 24 hours at 600 ° C. for 1 hour.
This alloy was pulverized, classified and compounded according to a conventional method to prepare a magnet material having a particle diameter of 53 to 200 μm. On the other hand, a diglycidyl phenyl ether represented by the following general formula, that is, 4 / 4'-bis (2,3-epoxypropyl) phenyl ether Suspension polymerization of methylmethacrylate and acrylonitrile in the presence, by the so-called in-situ polymerization method at room temperature liquid epoxy resin as the inclusion material, a copolymer of methylmethacrylate and acrylonitrile as a cell micro The capsule was adjusted. The content of the epoxy resin, which is the inclusion substance, was 70% by weight, and the average particle size was
16 μm. Further, 2-ethyl-4-methylimidazole was prepared as one of the thermopolymerizable resin constituents to prepare a resin magnet material which can be used for powder molding having the following composition.

Sm (Co, Cu, Fe, Zr) ₇ ...... 95.9% by weight Microcapsules ...... 4.0% by weight 2-Ethyl-4-methylimidazole ...... 0.1% by weight Magnetically different the above resin magnet material in the axial direction in the cylindrical cavity. A green body having a diameter of 10 mm was molded in a magnetic field of 15 KOe at a pressure of 8 ton / cm ² using a powder molding machine capable of squaring.
Although powder flowability of 50 to 60 sec / 50 g was observed at the stage before molding, the surface of the green body was slightly moistened by diglycidyl phenyl ether eluted by mechanical destruction of the microcapsules. Moreover, neither cracks nor partial omission of the magnet material was observed in the obtained green body. By heating such a green body at 120 ° C. for 30 minutes, the magnetic characteristics of a resin magnet having a density of 6.85 g / cm ³ were a residual magnetic flux density of 7.6 KG and a maximum energy product of 12.5 MGOe. Even when the resin magnet material was stored for 30 days at 40 ° C before the green body was molded, and the resin magnet was manufactured under the same conditions, the moldability, the appearance of the green body, and the magnetic properties did not change. There wasn't.

Comparative Example 1. Sm (Co, Cu, Fe, Zr) ₇ prepared under the same conditions as in Example 1
96.0% by weight, diglycidyl phenyl ether or 4,4'-bis (2,3-epoxypropyl) phenyl ether, 3.8 parts by weight, 2-ethyl-4-methylimidazole
0.2 parts by weight was mixed and immediately a resin magnet was constructed. Since the fluidity of the powder molding material is impaired due to diglycidyl phenyl ether, it is difficult to uniformly fill the cavity, and at the stage of the green body part of the magnet material easily falls off and is difficult to handle. Met. The magnetic characteristics of resin magnets with a density of 6.5 g / cm ³ are the residual magnetic flux density of 6.8 K.
G, the maximum energy product was 10.6 MGOe, and it was already difficult to mold a green body when stored at 40 ° C for 3 days at the stage of resin magnet material.

Example 2. Nd ₁₅ , Fe ₇₅ , B ₁₀ quenched ribbon was compressed at room temperature to form a green body, hot-pressed at 700 ° C and die-up sent to make it easy to magnetize at a relative density of 98-99%. An alloy with the shaft in the compression direction was used. This alloy is pulverized, classified and compounded according to a conventional method to obtain a particle size of 53-200.
The magnet material was adjusted to μm. On the other hand, a so-called in-situ polymerization method of suspension-polymerizing vinylidene chloride and acrylonitrile in the presence of 11% butyl glycidyl ether-substituted DGEBA was used as an encapsulating material for an epoxy resin that was liquid at room temperature, and the copolymerization of vinylidene chloride and acrylonitrile was performed. Microcapsules containing the polymer as a cell were prepared.

Further, microcapsules containing 4-methylhexahydrophthalic anhydride as an encapsulating substance and a cell of a copolymer of vinylidene chloride and acrylonitrile were prepared. The content of the encapsulated substance in these microcapsules was 70% by weight, and the average particle size was 10 μm. In addition, imidazole was prepared as a curing accelerator as a component of the thermopolymerizable resin to obtain a resin magnet material having the following composition.

Nd ₁₅ , Fe ₇₅ , B ₁₀ ...... 97% by weight Microcapsule I ・ ・ ・ 2.0% by weight Microcapsule II ・ ・ ・ 0.9% by weight Curing accelerator ・ ・ ・ 0.1% by weight However, the above microcapsules I and II are 11 respectively.
% Butyl glycidyl ether-substituted DGEBA and 4-methylhexahydrophthalic anhydride were included as encapsulating substances.

The resin magnet material was made into a green body having a diameter of 10 mm by a powder molding apparatus under the same conditions as in Example 1 under a magnetic field of 15 KOE and a pressure of 8 ton / cm ² . In addition, at the stage before molding, 50-60sec / 50g
Although the powder fluidity was observed, the surface of the green body was in a wet state due to the elution of the substance encapsulated in the microcapsules. The magnetic properties of a resin magnet obtained by heating such a green body at 120 ° C. for 1 hour had a residual magnetic flux density of 8.9 KG and a maximum energy product of 16 MGOe. Even when the resin magnet was manufactured under the same conditions from the stage before the green body was formed, that is, the resin magnet material was stored at 40 ° C for 30 days, the formability, the appearance of the green body, and the magnetic characteristics did not change. I couldn't do it.

EFFECTS OF THE INVENTION As described above, according to the method for producing a resin magnet according to the present invention, it is easy to mix the binder, that is, the thermopolymerizable resin constituent component. In addition, even thermosetting resin components that are liquid at room temperature can be used for forming green bodies in a state where they are isolated from other components by microcapsules, so that not only can fluidity be ensured as a powder molding material, Since it can maintain an inactive state, it has excellent storage stability. Especially during storage as a resin magnet material, thermopolymerizable resin components do not cause a thickening phenomenon based on mutual polymerization,
Since the magnet material can move freely as individual particles, it is effective in increasing the degree of orientation in powder molding in a magnetic field. In addition, since it is not necessary to heat and cool the softening temperature of the binder, which is a thermopolymerizable resin composition, when molding the green body, it is not necessary to maintain quality and performance when manufacturing resin magnets with high magnetic performance. It is clear that it is effective for securing.

Claims (2)

(57) [Claims] 1. One or more microcapsules containing a thermopolymerizable resin component as an encapsulating substance as a binder component, and a part of the microcapsules or a part of the microcapsules when the binder and the magnetic material are molded into a green body. Is a method for producing a resin magnet, in which the whole amount is mechanically destroyed to elute the encapsulated substance, and then the binder component is polymerized and cured. 2. The magnet material is Fe _100-xyz Cox Ndy Bz.
(However, 0 ≦ x ≧ 30, 10 ≦ y ≦ 28, 2 ≦ z ≦ 12, y + x ≦ 34,
6z + y ≧ 34, wherein _x , _y , and _z represent the atomic% of Co, Nd, and B), and are particles having a magnetic anisotropy of several tens to several hundreds μm. The method for producing a resin magnet according to item 1.