JPH0845722A - Composition for resin-bonded magnet and method for producing resin-bonded magnet using the composition - Google Patents

Abstract

(57) [Summary] [Structure] (A) _A magnetic powder having an anisotropic magnetic field (H _A ) of 50 kOe or more, (B) a polyamide resin, and (C) an epoxy group, an amino group and a carboxyl group. A composition for a resin-bonded magnet, which comprises a modified silicone oil having at least one group. [Effect] The resin-bonded magnet composition of the present invention can provide a resin-bonded magnet having excellent moldability, excellent magnetic properties, and excellent physical properties (especially mechanical strength). . Therefore, applications requiring all formability, magnetic properties, and mechanical strength, such as general household appliances, communications,
It is useful in a wide range of fields such as audio equipment, medical equipment, and general industrial equipment. Further, this composition is suitable for injection molding and extrusion molding because the viscosity is not too high even if the content ratio of the magnetic powder is 80% by weight or more, and thus the composition is suitable for thin-walled magnets and magnets with complicated shapes. It can be easily manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-bonded magnet composition which gives a magnet excellent in magnetic properties, moldability and mechanical strength, and a method for producing a resin-bonded magnet using the composition.

[0002]

2. Description of the Related Art Magnets such as ferrite magnets, alnico magnets and rare earth magnets are widely used for various purposes including motors. Among them, the resin-bonded magnet is obtained by blending magnetic powder with a binder such as polyamide resin and melt-molding it with an injection molding machine, etc. Although it is inferior, it has advantages such as (1) excellent moldability, high dimensional accuracy, thin wall and complicated shape, and (2) good mechanical strength.

[0003]

In recent years, small motors,
With the miniaturization of equipment such as audio equipment and office automation equipment, resin-bonded magnets are required to have better magnetic characteristics, moldability and physical characteristics (for example, mechanical strength). In order to improve the magnetic properties of the resin-bonded magnet, the mixing ratio of the magnetic powder may be increased. However, in the conventionally known composition composed of the magnetic powder and the polyamide resin binder, the mixing ratio of the magnetic powder is 80% by weight or more. In this case, there is a disadvantage that the viscosity is rapidly increased during melt molding, which makes molding difficult. Further, in order to improve moldability, it has been proposed to add a lubricant for thermoplastic resins such as stearic acid-based metal soap and paraffins together with the polyamide resin, but this is insufficient.

Therefore, an object of the present invention is to produce a resin-bonded magnet composition which gives a magnet having good moldability and excellent magnetic and mechanical properties, and a resin-bonded magnet using the composition. To provide a method.

[0005]

In order to solve the above-mentioned problems, the present invention provides (A) a magnetic powder having an anisotropic magnetic field (H _A ) of 50 kOe or more, (B) a polyamide resin, and (C) an epoxy. A resin-bonded magnet composition containing a modified silicone oil having at least one group selected from the group consisting of a group, an amino group and a carboxyl group.

The present invention also provides a method for producing a resin-bonded magnet, which comprises molding the resin-bonded magnet composition.

Component (A) The magnetic powder of component (A) used in the present invention has an anisotropic magnetic field (H
_{If A} ) is a magnetic powder of 50 kOe or more, the magnetic powder usually used for resin-bonded magnets can be used as the constraint Sm. For example, SmCo ₅ system, Sm ₂ (C
o, Fe, Zr, V) ₁₇ system, Sm ₂ (Co, Cu, F)
e, Zr) ₁₇ system, Sm ₂ (Co, Cu, Fe, Zr, T
e) ₁₇ system, Sm ₂ (Co, Cu, Fe, Ta, Te) ₁₇
Rare earth-cobalt system, such as Nd-Fe-Co
-B system, Nd-Dy-Fe-B system, Nd-Fe-B system, etc. rare earth-iron-boron system, for example, Sm-Fe-N system,
Rare earth-iron-nitrogen based magnetic powders such as Nd-Fe-Ti-N-based and Nd-Fe-VN-based are mentioned.

The particle size of the magnetic powder as the component (A) is preferably 200 μm or less on average, and particularly preferably 100 on average.
μm or less.

The content of the component (A) in the composition of the present invention is preferably in the range of 80 to 95% by weight. If the content ratio of the component (A) is too high, the kneading torque and fluidity of the composition may be lowered to make molding difficult, and if it is too low, desired magnetic properties cannot be obtained.

Further, in the composition of the present invention, as the magnetic powder of the component (A), an alloy powder obtained by a liquid quenching method of Nd-Fe-B system or an Sm-Fe-N system alloy powder is particularly preferable. When the above is used, for example, the mixing ratio of the magnetic powder can be increased to 95% by weight or more, and a resin-bonded magnet having extremely excellent magnetic characteristics can be obtained. Since the Nd-Fe-B based magnetic powder obtained by the liquid quenching method has a unique scale-like shape, it is preferably crushed by a jet mill or a ball mill before use.

Component (B) The component (B) component polyamide resin acts as a binder for the magnetic powder, and the polyamide resin used in the present invention is not particularly limited, and examples thereof include nylon 6 and nylon. 66, nylon 11, nylon 1
2, nylon 612, aromatic nylon and the like,
In addition, two or more kinds of these copolymers, or those whose end groups are treated with other compounds such as fatty acids such as stearic acid, palmitic acid, and linoleic acid, and linear or branched alkyl groups are also used. It is possible.

It is desirable that the melt viscosity and the molecular weight of the component (B) polyamide resin are as low as possible in the range where the desired mechanical strength can be obtained. Specifically, the molecular weight is preferably 35,000.
It is 0 or less, more preferably 10,000 to 25,000.

The shape of the polyamide resin as the component (B) may be any of powder, bead, pellet and the like, and is not particularly limited, but powder is preferable in view of uniform mixing with the magnetic powder. .

The polyamide resin as the component (B) can be used alone or in combination of two or more.

Component (C) The component (C) is a modified silicone oil having at least one group selected from the group consisting of epoxy groups, amino groups and carboxyl groups. The epoxy group, amino group or carboxyl group is, for example, an alkylene group having 1 to 10 carbon atoms such as a propylene group; for example, an alkyleneoxy group having 1 to 10 carbon atoms such as -C ₃ H ₆ O-; _{-C 3 H 6 O (CH 2} CH 2 O) a C 3 H 6 O- ( where, a is an integer of 1 to 100.) divalent polyether group; via a divalent organic group It is introduced into the silicon atom of the silicone oil. Further, the epoxy group, amino group or carboxyl group may be introduced into either the side chain or the terminal of the silicone oil, and may be introduced into both the side chain and the terminal of course.

The viscosity of the modified silicone oil as the component (C) is not particularly limited, but usually 10 cSt to 10
It is in the range of 000 cSt (25 ° C.). The molecular weight is in the range of about 1,000 to 500,000.

Examples of the modified silicone oil as the component (C) include, for example, the following general formula (1):

Embedded image [In the formula, R ¹ is, for example,

Embedded image (M is an integer of 1 or more) epoxy group-containing organic group such as, for _{example, - (CH 2) m NH} 2, - (CH 2) x -NH- (C
_{H 2) y -NH 2 (m} , x, y is an integer of 1 or more) amino group-containing organic group such as, for _{example, - (CH 2) x COOH} , - (CH 2) x -CH (C
_{OOH) 2, - (CH 2} ) x -CH (COOH) - (C
H ₂ ) _y —COOH, (x and y are integers of 1 or more) such as a carboxyl group-containing organic group, and when plural R ^1's are present, they may be the same or different. R ² is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms such as a methyl group and an ethyl group;
For example, an aryl group such as a phenyl group; a monovalent organic group, and when a plurality of R ^2's are present, they may be the same or different. m is an integer of 0 to 3, and n is an integer of 0 to 3. s, t and u are s ≧ 0, t ≧ 0, u ≧ 0,
It is an integer that satisfies 1 ≦ s + t + u ≦ 7,000. However, m, n, t, and u do not become 0 at the same time. ] The compound represented by these is mentioned.

Specifically, dimethyl silicone oil,
Epoxy on the terminal and / or side chain of diethyl silicone oil, methyl ethyl silicone oil, methyl phenyl silicone oil, ethyl phenyl silicone oil, diphenyl silicone oil, methyl hydrogen silicone oil, ethyl hydrogen silicone oil, phenyl hydrogen silicone oil, etc. Examples thereof include those into which at least one kind of group selected from the group consisting of a group, an amino group and a carboxyl group is introduced, but not limited thereto.

The modified silicone oil as the component (C) is used alone or in combination of two or more.

The content ratio of the component (C) is in the range of 0.01 to 50 parts by weight, preferably 0.1 to 20 parts by weight, based on 100 parts by weight of the polyamide resin of the component (B). And more preferably 1 to 10 parts by weight.
When the content ratio of the component (C) is less than 0.01 parts by weight relative to 100 parts by weight of the component (B), the moldability is lowered, and as a result, the content of the magnetic powder cannot be increased, which is high. It is not possible to obtain a magnet with magnetic characteristics. Further, when the content ratio of the component (C) exceeds 50 parts by weight relative to 100 parts by weight of the component (B), desired physical properties (especially mechanical strength)
Can't get

In addition, the component (B) in the composition of the present invention
The total content of the component (C) is preferably in the range of 3 to 20 parts by weight, more preferably 5 to 1 with respect to 100 parts by weight of the component (A).
A range of 5 parts by weight is preferred.

The component (C) is the magnetic powder of the component (A) and the component (B).
It may be mixed at the same time with the component polyamide resin, but in advance
It may be mixed with the polyamide resin as the component (B).

Other Components In the composition of the present invention, in addition to the components (A) to (C) described above, a silane-based, titanium-based, or aluminum-based surface treatment agent, that is, a coupling agent, etc. may be added, if necessary. Can be compounded in the range of 0.1 to 3.0% by weight with respect to the magnetic powder of the component (A). Examples of the coupling agent include vinyltriethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ- Silane coupling agents such as aminopropylmethyldimethoxysilane and γ-mercaptopropyltrimethoxysilane; for example, isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate. , Tetraoctyl bis (ditridecyl phosphite) titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl tridecyl benzene sulfonyl titanate Titanium coupling agents such as over preparative; for example, aluminum-based coupling agents such as acetoalkoxyaluminum diisopropylate be mentioned as a typical example.

In addition to the above components, the composition of the present invention may contain a plastic molding lubricant, various stabilizers and the like. Examples of lubricants include waxes such as paraffin wax, liquid paraffin, polyethylene wax, polypropylene wax, ester wax, carnauba wax, and microwax; for example, stearic acid, 1,2-oxystearic acid, lauric acid,
Fatty acids such as palmitic acid and oleic acid; for example, calcium stearate, barium stearate, magnesium stearate, lithium stearate, zinc stearate, aluminum stearate, calcium laurate, zinc linoleate, calcium ricinoleate, 2-
Fatty acid salts such as zinc ethylhexoate (metal soaps);
For example, 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, diamide. Stearyl adipic acid amide, ethylenebisoleic acid amide,
Fatty acid amides such as dioleyl adipic acid amide and N-stearyl stearic acid amide; for example, fatty acid esters such as butyl stearate; alcohols such as ethylene glycol and stearyl alcohol;
Polyethylene glycol, polypropylene glycol,
Polytetramethylene glycol and polyethers such as modified compounds thereof; for example, polysiloxanes such as dimethylpolysiloxane and silicone grease; for example, fluorine compounds such as fluorine oil, fluorine grease, and fluorine-containing resin powder; Examples thereof include powders of inorganic compounds such as silicon nitride, silicon carbide, magnesium oxide, alumina, silicon dioxide and molybdenum disulfide. The content ratio of lubricant is
It is usually in the range of 0.1 to 15 parts by weight with respect to 100 parts by weight of the component (A).

As the stabilizer, for example, bis (2,2,2
6,6-tetramethyl-4-piperidyl) sebacate,
Bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- {3- (3,5-di-
Tert-Butyl-4-hydroxyphenyl) propionyloxy} ethyl] -4- {3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy}-
2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-
1,2,3-Triazaspiro [4,5] undecane-
2,4-dione, 4-benzoyloxy-2,2,6
6-tetramethylpiperidine, dimethyl succinate-1-
(2-hydroxyethyl) -4-hydroxy-2,2
6,6-Tetramethylpiperidine polycondensate, poly [[6
-(1,1,3,3-tetramethylbutyl) imino-
1,3,5-triazine-2,4-diyl] [(2,
2,6,6-Tetramethyl-4-piperidyl) imino]
Hexamethylene [[2,2,6,6-tetramethyl-4
-Piperidyl) imino]], 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl ) And other hindered amine stabilizers, as well as phenolic, phosphite, thioether and other antioxidants.

Preparation of Composition The composition of the present invention is obtained by mixing the components (A) to (C) and, if necessary, the above-mentioned other components. The method of mixing is not particularly limited, for example, a method using a mixer such as a ribbon blender, a tumbler, a Nauter mixer, a Henschel mixer, a super mixer, or the like, or
It is carried out by a method using a kneading machine such as a Banbury mixer, a kneader, a roll, a kneader ruder, a single-screw extruder, or a twin-screw extruder.

The composition of the present invention can be obtained in the form of powder, beads, pellets or a mixture thereof, but pellets are preferable from the viewpoint of easy handling.

The resin-bonded magnet of the present invention is produced by molding the above composition using various thermoplastic resin molding machines. An injection molding machine and an extrusion molding machine are preferably used as the thermoplastic resin molding machine.

[0029]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

Material (A) Magnetic powder Magnetic powder SmCo ₅ type magnetic powder Anisotropic magnetic field: 246 kOe Product name: RCo ₅ alloy, Sumitomo Metal Mining Co., Ltd. Magnetic powder Nd-Fe-B type magnetic powder Anisotropic magnetic field: 70.4 kOe, trade name: MQP-B, manufactured by General Motors, USA

(B) Polyamide resin nylon 12 Product name: UBE nylon, 3014U, Ube Industries, Ltd.

(C) Modified silicone oil oil Side chain amino-modified dimethyl silicone oil Product name: BY16-850; Viscosity 1,100 cSt (Toray Dow Corning Silicone Co., Ltd.)

[Chemical 3] Oil side chain glycidyl-modified dimethyl silicone oil Product name: SF8413; Viscosity 8,000 cSt (Toray Dow Corning Silicone Co., Ltd.)

[Chemical 4] Oil carboxy-modified dimethyl silicone oil on both ends Product name: SF8418; Viscosity 2,500 cSt (Toray Dow Corning Silicone Co., Ltd.)

Embedded image Oil unmodified straight dimethyl silicone oil Product name: SH200 oil; viscosity 10,000 cSt (Toray Dow Corning Silicone Co., Ltd.)

[Chemical 6]

Examples 1 to 15 and Comparative Examples 1 to 4 In each Example and Comparative Example, compositions were prepared as follows. Preparation of Composition (A) to (C) in the amounts (parts by weight) shown in Tables 1 to 4, and 2.0 parts by weight of lithium stearate per 100 parts by weight of the component (B) as a lubricant. And dimethylpolysiloxane were mixed and stirred in a planetary mixer (40 rpm, 80 ° C.), then 760 mmHg, 120 ° C.
In an oven for 24 hours. The obtained mixture was mixed with a 20 mmφ single extruder (L / D = 25, CR
= 2.0, rotation speed = 20 rpm, 5 mmφ strand die, cylinder temperature 200 ° C. to 280 ° C., die temperature 2
It was extruded at 80 ° C., and a pellet compound of 5 mmφ × 5 mm was prepared with a hot cut pelletizer.

With respect to the obtained pellet compound,
The fluidity was evaluated by the following method. The results are shown in Table 1
4 shows.

-Fluidity (MFR) evaluation ASTM D1238-65T and ASTM D1430-5
8 etc., the fluidity of the obtained magnet was measured at a temperature of 250 using a high-performance flow tester manufactured by Shimadzu Corporation.
° C, load: 30 kgf, die shape: 1 mmφ x 1 m
m, preheat: Measured under the condition of 120 seconds. 1.5g
If the fluidity is not less than 1 minute, there is no problem in molding processability.

The pellet compounds obtained in the respective examples and comparative examples were molded in the following manner to produce magnets. The obtained pellet compound is molded using a magnetic field injection molding machine (trade name: J-20MII, manufactured by Japan Steel Works, Ltd.) at a molding temperature of 240 to 290 ° C. and a mold temperature of 100 to 1
Molded at 20 ℃, width 5mm × length 20mm × thickness 4mm
A resin-bonded magnet for test was obtained. Incidentally, only when magnetic powder was used as the component (A), molding was carried out in a mold in a magnetic field of 15 to 20 kOe.

The mechanical strength and magnetic properties of the magnets obtained in the respective examples and comparative examples were evaluated by the following methods. The results are shown in Tables 1 to 4.

Evaluation of mechanical strength (3-point bending strength) The bending strength of the obtained magnet was measured using an autograph manufactured by Shimadzu Corporation with reference to ASTM D790-66. The head speed was 2 mm / min, and the measurement was performed at room temperature. If the bending strength is 15.0 kgf / mm ² or more, the mechanical strength is sufficient. -Magnetic property evaluation The magnetic property of the obtained magnet was measured at room temperature with a Thiophie type magnetic flux meter. Tables 1 to 4 show the measurement results of (BH) max (maximum magnetic energy product) of the magnetic characteristics.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

Industrial Applicability The resin-bonded magnet composition of the present invention provides a resin-bonded magnet having excellent moldability, excellent magnetic properties, and excellent physical properties (especially mechanical strength). You can Therefore, it is useful in a wide range of fields, such as general home appliances, communication / audio equipment, medical equipment, and general industrial equipment, which require all of moldability, magnetic properties, and mechanical strength. Further, in particular, the resin-bonded magnet composition of the present invention is suitable for injection molding or extrusion molding because the viscosity is not too high and the fluidity is good even when the content ratio of the magnetic powder is 80% by weight or more. It is possible to easily manufacture a thin magnet and a magnet having a complicated shape.

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Claims (2)

[Claims] 1. A magnetic powder having an anisotropic magnetic field (H _A ) of 50 kOe or more, (B) a polyamide resin, and (C) at least one selected from the group consisting of epoxy groups, amino groups and carboxyl groups. Modified silicone oil having a group of 0.01 to 5 with respect to 100 parts by weight of the polyamide resin.
A resin-bonded magnet composition containing 0 part by weight. 2. A method for producing a resin-bonded magnet, which comprises molding the resin-bonded magnet composition according to claim 1.