JPH06295805A - Bond magnet forming material - Google Patents

Abstract

PURPOSE:To enhance moldability, mechanical strength and magnetic characteristics by composing a binder resin of a first component comprising a crystalline thermoplastic resin and a second component comprising a polyolefin based resin having melting point lower than that of the first component resin. CONSTITUTION:A magnetic powder, a binder resin, and various additive materials are kneaded. In this regard, the binder resin is composed of a first component comprising a crystalline thermoplastic resin, and a second component comprising a polyolefin based resin separated in phase from the first component resin and having melting point lower by 30 deg.C or more than that of the first component resin. The second component is added by 1-100 pts.wt. for 100 pts.wt. of first component. This material provides good moldability, sufficient mechanical strength, and high magnetic characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material capable of forming a bond magnet having a predetermined shape by injection molding or the like, that is, a magnetic powder and a binder resin for bonding particles forming the powder to each other. The present invention relates to a bond magnet forming material obtained by kneading with an additive material, and particularly, when a bond magnet is molded into a predetermined shape, good flow characteristics can be obtained, and the bond magnet produced by this has high magnetic characteristics and sufficient And mechanical strength.

[0002]

2. Description of the Related Art A bonded magnet in which particles forming a magnetic powder are bonded together by a binder resin can be easily molded into a predetermined shape by injection molding or the like, so that even a complicated shape can be integrally molded. It has excellent moldability compared to sintered magnets. In addition to this, since it has high mechanical strength, it is hard to crack or chip, and the dimensional accuracy is good,
In recent years, such bonded magnets have attracted particular attention, and their industrial application range is expanding.

Among such bonded magnets, the market for bonded magnets with high magnetic properties, which uses SmCo or NdFeB based rare earth magnet materials as magnetic powder, is growing rapidly.
Further, a bonded magnet made of SmFeN-based powder, which is a new magnetic material, is also useful. Such a bonded magnet is produced by kneading a magnetic powder, a binder resin that binds the particles forming the powder, and various additives to a bond magnet forming material by a method such as injection, extrusion, or compression. It is obtained by molding.

That is, for example, when a bonded magnet is obtained by injection molding, a mixture of a thermoplastic resin, a coupling agent such as silane or titanium, a lubricant and the like and magnetic powder is kneaded by an extruder or the like. After that, it is processed into pellets or powder, and the obtained pellets or powder is introduced into an injection molding machine. In such a bond magnet forming material, it is necessary to increase the content of the magnetic powder as much as possible in order to improve the magnetic properties of the bond magnet. However, since the flowability of the bonded magnet forming material decreases as the content of the magnetic powder increases, the content of the magnetic powder has an upper limit. In particular, when a fine powder having a diameter of 10 μm or less is used as the magnetic powder, the fluidity of the bond magnet forming material is significantly reduced.

When the fluidity of the bond magnet forming material is lowered, the moldability during the molding of the bond magnet is lowered, but not only that, the orientation of the particles forming the magnetic powder is lowered and the magnetic properties are lowered. It will be. That is, increasing the content of the magnetic powder for the purpose of improving the magnetic properties causes a decrease in the fluidity of the bond magnet forming material and a decrease in the magnetic properties.

In order to solve such a problem, a binder resin, a lubricant,
Many studies have been conducted on selection of various additives such as coupling agents, and addition methods and kneading methods of these. Among them, as the binder resin, it is possible to improve various physical properties by using a mixture of two or more kinds of resins, for example, JP-A-63-181402, JP-A-63-181403, Japanese Patent Laid-Open No. 2-1
No. 85002 is disclosed.

According to these publications, different types of polyamide resins are used in combination as the polyamide resin that is preferably used as the binder resin when forming the bonded magnet by injection molding (for example, 6,6-nylon and 12).
-Combined with nylon), it is possible to improve mechanical strength, increase fluidity at the time of melting and reduce kneading torque, thereby improving moldability. Has been done.

[0008]

However, in the technique disclosed in the above publication, since the resins to be used together are one of the polyamide resins, they are mixed with each other in a molten state to form a uniform resin, As for the glass transition point, glass transition point, and other physical properties, only intermediate values of the physical properties of the respective resins can be obtained.

For example, as described in JP-A-2-185002, when a binder resin containing 6,6-nylon and 12-nylon is used, or modified nylon having a low melting point of 6,6-nylon. In the case of using the binder resin consisting of, the fluidity of the bond magnet forming material is improved and the hygroscopicity is lowered, as compared with the case where only 6,6-nylon is used as the binder resin. Although the toughness of the magnet is improved, the following problems also occur.

That is, as compared with the case where only 6,6-nylon is used as the binder resin, the melting point and glass transition point of the binder resin are lowered and the heat distortion temperature is lowered, so that the mechanical properties of the obtained bonded magnet are increased. However, there is a problem in that the mechanical strength and the rigidity are deteriorated, and it is not practically useful. The present invention has been made by paying attention to such problems of the prior art, and has a molding processability in molding into a bond magnet, and sufficient mechanical strength and high magnetic properties when used as a bond magnet. It is an object of the present invention to provide a bonded magnet molding material having both of the above.

[0011]

In order to achieve the above object, the present invention is a bond obtained by kneading a magnetic powder, a binder resin for bonding particles forming the powder, and various additives. In the magnet forming material, the binder resin is phase-separated from the first component made of a crystalline thermoplastic resin and the resin forming the first component, and is made of a polyolefin resin having a melting point lower than that of the resin by 30 ° C. or more. A second aspect of the present invention is to provide a bond magnet forming material, characterized in that the second component is added in an amount of 1 part by weight or more and less than 100 parts by weight with respect to 100 parts by weight of the first component. .

The magnetic powder, binder resin, and various additives that compose the bonded magnet forming material of the present invention will be described in detail below. <Magnetic powder> Examples of the magnetic powder that can be used in the present invention include magnetic powders such as SmCo-based, NdFeB-based, SmFeN-based, and ferrite-based magnetic powders. The material is contained in a proportion of 70 to 97 wt%, preferably 80 to 95 wt%. <First Component of Binder Resin> As the first component of the binder resin in the present invention, there is a crystalline thermoplastic resin which is conventionally known to constitute the binder resin by itself. Specifically, 12-nylon, 6
-Nylon, polyamide resin such as 6,6-nylon, polyacetal, polyimide, polysulfone, polybutylene terephthalate, polyethylene terephthalate, polyarylate, polyphenylene oxide and its modified products,
Resins called engineered plastics such as polyether sulfone, polyphenylene sulfide, polyamide imide, polyoxybenzene, and polyether ketone, and liquid crystal resins such as polyaramid, wholly aromatic polyester, and polyesteramide, and one of these, or A combination of two or more can be used.

From these, an appropriate resin is selected according to the required performance such as heat resistance, mechanical strength, elasticity, dimensional accuracy, oil resistance, chemical resistance, and weather resistance. Of the above crystalline thermoplastic resins, mechanical strength, dimensional accuracy,
Polyamide resins such as 12-nylon, 6-nylon, 6,6-nylon, etc., which have a good balance of cost and molding processability and have good affinity with magnetic powder in comparison with other resins, It is particularly preferable as the resin forming the first component of the binder resin in the invention.

The first component of such a binder resin is
It is preferable to contain the bonded magnet forming material in the range of 2 to 25% by weight. If this content is less than 2% by weight, the fluidity of the bonded magnet molding material during melting will be extremely poor, and if it exceeds 25% by weight, the magnetic powder content will be small and the magnetic properties will be poor. The obtained bonded magnet is poor in practicality as a permanent magnet application.
A more preferable range of this content is 4 to 15% by weight. <Second Component of Binder Resin> The second component of the binder resin of the present invention is a polyolefin that is phase-separated from the resin of the first component and has a melting point lower than that of the resin of the first component by 30 ° C. or more. It is made of a system resin.

Specifically, polyethylene, polypropylene, polyisoprene, polyisobutylene, polybutene-
1, a copolymer of a vinyl resin and an olefin resin such as polyethylene-propylene copolymer, polystyrene, polystyrene-butadiene, ethylene-vinyl acetate copolymer,
Examples thereof include copolymers with acrylic resins such as ethylene-ethyl acrylate, acrylonitrile-styrene copolymers, and copolymers thereof.

Of these, one or a combination of two or more of the resins corresponding to the resin phase-separated from the above is selected and used according to the resin selected as the first component of the binder resin. . In selecting these resins, the solubility parameter of each resin serves as an index,
It is expected that the greater the difference between these values, the greater the degree of phase separation.

The solubility parameter values are calculated from the group mol traction constant, Small's calculation method, viscosity method,
It is determined by a swelling method, a gas chromatography method, a surface tension method, a thermal expansion method, the solubility of a polymer in a solvent, or the like, and the difference in the solubility parameter of the binder resin to the second component is 1. A value of 0 or more, preferably 1.5 or more is selected.

Table 1 below shows an example of solubility parameters calculated by Small's calculation method for thermoplastic resins that can be used as the first component or the second component of the binder resin in the present invention, and their melting points. , Glass transition point, and density.

[0019]

[Table 1]

Referring to Table 1, examples of combinations of resins that can be used as the first component and the second component of the binder resin in the present invention are shown below.
When nylon is used, polyethylene is used as the second component, when 6-nylon is used as the first component, polyethylene or polypropylene is used as the second component, and when 6,6-nylon is used as the first component. As the second component, polyethylene, polypropylene, polystyrene and the like are particularly effective.

As the first component of the binder resin,
Polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene oxide,
Even when polyphenylene sulfide or the like is used, polyethylene, polypropylene, polystyrene or the like, or a copolymer thereof or a copolymer containing these is effectively used as the second component.

In the bonded magnet forming material of the present invention,
As described above, the binder resin is composed of the first component and the second component, but a dispersion aid and a compatibilizing agent may be used in order to stabilize the thermoplastic resin forming each component in a mixed state. In that case, for example, a resin, a resin modified product, or the like, which is composed of a compound having an affinity for both thermoplastic resins that form the first component and the second component, is used.

Further, the content of the second component of the binder resin is preferably 0.1 to 5.0% by weight in the bond magnet forming material. It is added in an amount of 1 part by weight or more and less than 100 parts by weight with respect to 100 parts by weight of the crystalline thermoplastic resin as a component. And, the addition amount to 100 parts by weight of the first component is preferably 1 to 95 parts by weight, and more preferably 4 to 80 parts by weight. <Various Additives> The bonded magnet forming material of the present invention may contain various additives such as a silane coupling agent and a lubricant.

Examples of the silane coupling agent that can be contained in the bonded magnet forming material of the present invention include the following silane compounds. That is, vinyltriethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4epoxycyclohexylethyltrimethoxysilane), γ
-Glycidoxypropyltrimethoxysilane, γ-glycidoxymethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β
(Aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-
Phenyl-γ-aminopropyltrimethoxysilane, γ
-Mercaptopropyltrimethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane, etc. Is.

These silane compounds may be contained alone or in combination of two or more, and the content thereof is preferably 0.01 to 5.0% by weight in the bond magnet forming material. The type of silane compound suitable for the inclusion depends on the type of the resin constituting the first component selected as the binder resin. For example, when a polyamide resin is used as the first component, phenyltrimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, and diphenyldiethoxysilane are used as the silane compound because of its physical properties such as polarity and boiling point. Preferably.

In the bonded magnet forming material of the present invention, when the content of the magnetic powder is 90% by weight or more, the lubricant is selected depending on the kind of the binder resin and the magnetic powder to be contained, the particle size of the magnetic powder and the like. It may be preferable to add. Examples of lubricants that can be contained in the bonded magnet forming material of the present invention include waxes such as paraffin wax, liquid paraffin, polyethylene wax, polypropylene wax, ester wax, carnauba, and microwax, stearic acid, 12-oxystearic acid, and laurin. Fatty acids such as acids, zinc stearate, calcium stearate, barium stearate, aluminum stearate, magnesium stearate, calcium laurate, zinc linoleate, calcium ricinoleate, 2
-Fatty acid salts such as zinc ethylhexoate, stearic acid amide, oleic acid amide, erucic acid amide, behenic acid amide, palmitic acid amide, lauric acid amide, hydroxystearic acid amide, methylenebisstearic acid amide, ethylenebisstearic acid Amide, ethylenebislauric acid amide, distearyl adipic acid amide,
Ethylene bisoleic acid amide, dioleyl adipic acid amide, N-stearylsuaric acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid amide, methylol behenic acid amide and other fatty acid amides, butyl stearate Fatty acid esters such as, ethylene glycol, alcohols such as stearyl alcohol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol and polyethers composed of these modified products, silicone oil, polysiloxanes such as silicone grease, fluorine-based oil, Examples thereof include fluorine-based grease, fluorine compounds called fluorine-containing resin powder, and inorganic compound powder such as silicon nitride, silicon carbide, magnesium oxide, alumina and silica gel.

One or more of these lubricants are used. When at least one of waxes, polyethers and fatty acid amides is contained as a lubricant, the moldability of the bond magnet forming material is improved. It is particularly preferable because it greatly improves. The amount of the lubricant added is preferably 5% by weight or less in the bond magnet forming material, and more preferably 0.1 to 2% by weight.

The bonded magnet forming material of the present invention includes
As an additive other than the above, for example, in order to improve the heat resistance of the thermoplastic resin forming the binder resin and the magnetic powder, a stabilizer such as a heat aging inhibitor or an antioxidant is added during the preparation of the bond magnet forming material. Can be added at each stage of mixing, kneading and molding. Alternatively, such a stabilizer may be added in advance to the thermoplastic resin or the additive before the preparation of the bonded magnet forming material.

As such stabilizers, hindered phenol-based, amine-based primary antioxidants, sulfur-based and phosphorus-based secondary antioxidants are used. In particular, when the first component of the binder resin is a polyamide resin, it is effective to use phosphorus-based triphenyl phosphite or the like. Next, an example of a method for preparing the bonded magnet forming material of the present invention having such a configuration will be described below. <Method for Preparing Bonded Magnet Forming Material> (1) Mixing Step First, the magnetic powder, the thermosetting resin that is the first component of the binder resin, the polyolefin resin that is the second component, the silane coupling agent or the silane monomer, and Mix the lubricant (only when necessary) in the mixer.

At this time, the resin constituting each component of the binder resin may be introduced into the mixer in any form such as pellets, beads, powder, and paste, but in order to obtain a highly homogeneous mixture. It is preferably introduced in the form of fine particles. Further, it is preferable to add a solvent because the silane coupling agent, the silane monomer, or the lubricant can be mixed more uniformly.

The mixer used for mixing is not particularly limited, and examples thereof include a ribbon mixer, a V-type mixer, a rotary mixer, a Henschel mixer, a flash mixer, and a Nauta mixer. Also,
A method of pulverizing and mixing using a rotary ball mill, a vibrating ball mill, a planetary ball mill, a wet mill, a jet mill, a hammer mill, a cutter mill or the like is also effective. (2) Kneading step The mixture obtained by the above step is introduced into a batch kneader such as Brabender, a Banbury mixer, a Henschel mixer, a helical rotor, a roll, a single-screw extruder, a twin-screw extruder, etc. The one component and the second component are kneaded while melting. Then, the kneading temperature is set to a temperature within a range (for example, 50 to 400 ° C.) in which the resins forming both components are melted but not decomposed.

Then, the obtained kneaded product is extruded into a strand or a sheet and cut as it is by a cutter, or cut by hot cutting or underwater cutting to prepare pellets of a bond magnet forming material. Alternatively, the obtained kneaded product is cooled and solidified in a block shape, and is then pulverized to prepare a powder of a bond magnet forming material.

The bond magnet forming material of the present invention thus obtained can be used as a bond magnet having a predetermined shape, for example, by the following method. <Method for forming bonded magnet> The bonded magnet forming material obtained in the form of pellets or powder is heated and melted, and is molded into a predetermined shape by injection molding, extrusion molding, compression molding or the like while applying a magnetic field as necessary. In the case of extrusion molding, it can be performed at the same time as kneading the bonded magnet forming material. Among these methods, it is preferable to use injection molding because a bonded magnet excellent in surface smoothness and magnetic characteristics can be obtained and the degree of freedom in molding shape is large.

Then, usually, the obtained molded body is further magnetized to obtain a permanent magnet. When magnetizing the molded body obtained from the bonded magnet forming material of the present invention, a conventionally known method, that is, for example, an electromagnet that generates a static magnetic field, a condenser magnetizer that generates a pulse magnetic field, etc. Is done using. The magnetic field strength for sufficient magnetization is preferably 15 kOe or more, more preferably 25 kOe or more.

[0035]

In the bonded magnet forming material of the present invention, the binder resin is phase-separated from the first component composed of the crystalline thermoplastic resin and the resin constituting the first component, and has a melting point higher than that of the resin. Since it is composed of the second component composed of a polyolefin resin having a temperature lower than 30 ° C., when the material is brought into a molten state when the bonded magnet is molded, the binder resin has a microscopic “sea-island” structure.

That is, the first component becomes the "sea" having a "sea-island" structure, and the second component exists in the binder resin in a state of "island" floating on the "sea". As a result, the first component acts substantially as a binder for the magnetic powder, and the second component acts like a lubricant. Further, since both components do not mix even in the molten state, the addition of the second component does not substantially change the melting point, glass transition point, and other physical properties of the first component which serves as a binder.

As a result, the bonded magnet forming material of the present invention has a high melting point, a high melting point, a glass transition point and other properties which are contained in the first component made of the crystalline thermoplastic resin while having a high fluidity at the time of melting. The physical properties are retained. Further, the higher the fluidity, the more the magnetic powder can be mixed in the bonded magnet forming material at a considerably high ratio. Therefore, the bond magnet forming material of the present invention has both moldability when molding into a bond magnet and sufficient mechanical strength and high magnetic properties when used as a bond magnet.

As described above, the second component constituting the binder resin becomes an “island” when the first component is “sea”, and therefore, the second component is added to 100 parts by weight of the first component. It is necessary that the addition ratio of the components is less than the same amount, that is, 1 part by weight or more and less than 100 parts by weight.

[0039]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. <Example 1> Sm _8.4 Fe _72.1 having an average particle size of 2.3 μm
N _12.9 H _0.4 O _5.6 magnetic powder; 2790 g; diphenyldimethoxysilane; 30 g; 12-nylon (UBE Nylon-12 P-3014U made by Ube Industries); 189 g; low-density polyethylene (Suntech made by Asahi Kasei Kogyo) LD F1920); 2
1 g and were introduced into a rotary mixer and mixed for 10 minutes.

The obtained mixture was introduced into a 30 mm twin-screw extruder (LABO-TEX30 manufactured by Japan Steel Works), and 30 to 35
Kneading was performed under the conditions of rpm and 230 ° C. And the pellet of the bond magnet forming material was obtained by cutting the kneaded material that had come out from the extruder in a strand shape into a predetermined size with a cutter. The pellets were introduced into a 20 ton injection molding machine (J-20ME manufactured by Japan Steel Works), cylinder temperature 240 ° C, mold temperature 100 ° C, injection pressure 1800kg / c.
Molded under a magnetic field of m ² with a diameter of 15 mm,
Button-shaped molded body with a thickness of 5 mm, length 125 mm, width 12.
A strip-shaped molded body having a thickness of 5 mm and a thickness of 3.2 mm was obtained.

The magnetic properties, melt flow rate, bending strength, and density were measured using each of these molded bodies and pellets before molding. The density was calculated by measuring the volume and mass of the button-shaped molded product, and the magnetic properties, melt flow rate, and bending strength were measured by the methods described below. << Magnetic Properties >> A button-shaped molded body was used, pulsed at 60 kOe at room temperature, and then subjected to a BH loop tracer (manufactured by Toei Industry Co., Ltd.) to obtain a residual magnetic flux density Br,
The intrinsic coercive force iHc, the maximum energy product BHmax, and the squareness ratio II were measured. <Melt flow index> Use pellets and apply them to a melt flow indexer (manufactured by Toyo Seiki), then 2
The measurement was carried out under the conditions of 80 ° C. and 10 kg / cm ² . << Bending Strength >> A strip-shaped molded body was used, and this was put into a testing machine manufactured by Instron and measured according to ASTM D-790. <Example 2> N- [beta] -aminoethyl- [gamma] -aminopropyltrimethoxysilane was used in place of diphenyldimethoxysilane in Example 1, and other than this, Example 1 was used.
The same mixture as above was prepared into a bond magnet forming material by the same method as in Example 1, and the molding of the bond magnet and the measurement of various physical properties were similarly performed. <Example 3> Instead of the low-density polyethylene in Example 1, high-density polyethylene (Suntech HDJ- manufactured by Asahi Kasei Corporation)
320) was used to prepare a bond magnet forming material in the same manner as in Example 1 except for the above, and a bond magnet was formed and various physical properties were measured in the same manner. . <Example 4> 6-nylon (Unitika nylon A-1030SR manufactured by Unitika) was used instead of 12-nylon in Example 1.
19 g, polypropylene (Polypropylene MS-640 manufactured by Tokuyama) was used in place of the low density polyethylene, and the same mixture as in Example 1 except for this was mixed at a kneading temperature of 250 ° C.
Other than the above, a bond magnet forming material was prepared by the same method as in Example 1, and the bond magnet was molded by the same method as in Example 1 except that the injection temperature was 260 ° C., and various physical properties were also measured. Example 5 Sm _8.4 Fe _72.1 having an average particle size of 2.3 μm
N _12.9 H _0.4 O _5.6 magnetic powder; 2820 g, diphenyldimethoxysilane; 6 g, 12-nylon; 144
g, low-density polyethylene; 36 g, ethylenebisstearic acid amide; 24 g, to prepare a bond magnet forming material in the same manner as in Example 1, and the same applies to molding of the bond magnet and measurement of various physical properties. I went to. <Example 6> 6,6-nylon (Asahi Kasei Kogyo Leona 1300S) was used in place of 6-nylon in Example 4,
Except for this, the same mixture as in Example 4 was mixed at a kneading temperature of 2
A bonded magnet forming material was prepared in the same manner as in Example 4 except that the temperature was 80 ° C., and the injection temperature was set at 280 ° C.
A bonded magnet was molded by the same method as in Example 1 and various physical properties were measured. <Example 7> 245 g of PBT (PBT 1401X-6 manufactured by Toray) was used instead of 12-nylon in Example 1, and the same mixture as in Example 1 except that the kneading temperature was 250 ° C was used. Was prepared into a bonded magnet forming material by the same method as in Example 1, and the bonded magnet was molded by the same method as in Example 1 except that the injection temperature was 260 ° C., and various physical properties were also measured. <Example 8> Sm _1.0 Co _5.0 having an average particle size of 5.4 μm
Magnetic powder; 2833 g, diphenyldimethoxysilane; 6 g, 12-nylon; 150 g, low density polyethylene; 17 g, ethylenebisstearic acid amide; 24
The mixture constituted by g was prepared into a bond magnet forming material by the same method as in Example 1, and the molding of the bond magnet and the measurement of various physical properties were also carried out in the same manner. <Example 9> NdFeB magnetic powder was used as the magnetic powder, and a mixture which was the same as in Example 5 except for this was prepared as a bond magnet forming material by the same method as in Example 5, and a bond magnet was molded. Also, the physical properties were measured in the same manner. <Comparative Example 1> The amount of 12-nylon added was 210 g,
A mixture which was the same as that of Example 1 except that the density polyethylene was not added was prepared into a bond magnet forming material by the same method as in Example 1, and the molding of the bond magnet and the measurement of various physical properties were similarly performed. went. <Comparative Example 2> A mixture was prepared in the same manner as in Example 4 except that polypropylene was not added and the amount of 6-nylon added was 240 g to prepare a bond magnet-forming material in the same manner as in Example 4, Molding of the bonded magnet and measurement of various physical properties were performed in the same manner. <Comparative Example 3> The amount of 12-nylon added was 180 g,
Example 5 was repeated except that low-density polyethylene was not added.
The same mixture as above was prepared into a bond magnet forming material by the same method as in Example 5, and the molding of the bond magnet and the measurement of various physical properties were also carried out in the same manner. <Comparative Example 4> The amount of 6,6-nylon added was 240 g, and polypropylene was not added.
The same mixture as above was prepared into a bond magnet forming material by the same method as in Example 6, and the molding of the bond magnet and the measurement of various physical properties were also carried out in the same manner. <Comparative Example 5> A mixed magnet forming material was prepared in the same manner as in Example 7, except that the amount of PBT added was 266 g and low-density polyethylene was not added, and otherwise the same as in Example 7 was prepared. Molding of the bonded magnet and measurement of various physical properties were performed in the same manner. <Comparative Example 6> The amount of 12-nylon added was 167 g,
Example 8 was repeated except that low-density polyethylene was not added.
The same mixture as above was prepared into a bond magnet forming material by the same method as in Example 8, and the molding of the bond magnet and the measurement of various physical properties were also carried out in the same manner. <Comparative Example 7> The addition amount of 12-nylon was set to 180 g,
Example 8 was repeated except that low-density polyethylene was not added.
The same mixture as above was prepared as a bond magnet forming material by the same method as in Example 9, and the molding of the bond magnet and the measurement of various physical properties were similarly performed.

Tables 2 and 3 below show the composition of the bonded magnet forming material and the results of the respective physical properties obtained by the measurement for each of the examples and comparative examples described above. In addition, LDPE in Table 2 is low density polyethylene, HDPE
Indicates high density polyethylene.

[0043]

[Table 2]

[0044]

[Table 3]

From these tables, it is understood that the bond magnet forming materials corresponding to the examples of the present invention have a remarkably large melt flow index (MFI) value as compared with the comparative examples. That is, it is understood that the bonded magnet forming material of the present invention has high fluidity when melted and is excellent in moldability when molding into a bonded magnet. Further, the bonded magnet produced by the bonded magnet forming material of the present invention has sufficient mechanical strength as a result of bending strength, and has high magnetic characteristics as a result of each magnetic characteristic. I understand.

[0046]

As described above, according to the bonded magnet forming material of the present invention, the binder resin is phase-separated from the first component composed of the crystalline thermoplastic resin and the resin constituting the first component. In addition, since it is composed of a second component composed of a polyolefin resin having a melting point lower than that of the above resin by 30 ° C. or more, good flow characteristics can be obtained when molding into a predetermined shape as a bond magnet, and it is produced by this. It is possible to impart high magnetic properties and sufficient mechanical strength to the bonded magnet.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // H01F 7/02 A

Claims (1)

[Claims] 1. A bond magnet forming material obtained by kneading a magnetic powder, a binder resin for bonding particles forming the powder, and various additives, wherein the binder resin is a crystalline thermoplastic resin. And a second component composed of a polyolefin-based resin that is phase-separated from the resin forming the first component and has a melting point lower than that of the resin by 30 ° C. or more. 1 part by weight or more of the second component with respect to 1 part
A bonded magnet forming material, which is added in a proportion of less than 00 parts by weight.