JP2988151B2 - Composition for bonded magnet and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonded magnet composition excellent in moldability and a bonded magnet excellent in magnetic properties obtained from the composition.

[0002]

2. Description of the Related Art Rare earth permanent magnets are being used in a wide range of fields from general home appliances, communication / audio equipment, medical equipment and general industrial equipment due to their excellent magnetic properties. Among these, bond-type magnets are formed by press molding by blending a magnetic binder with a resin binder.Therefore, compared to sintered-type magnets, (1) higher dimensional accuracy and molding into complex shapes are possible. It has the following advantages: (2) high uniformity of quality and performance; (3) good yield and good machinability. However, on the other hand, since the resin binder is used, there is a disadvantage that the magnetic properties of the magnet are impaired.

Recently, a bond obtained by using a liquid epoxy resin at room temperature as a resin binder has been proposed as satisfying the conflicting requirements of improving the magnetic properties and mechanical properties of a magnet. Magnets have been proposed. That is, by using such an epoxy resin, it is possible to improve the magnetic properties of the magnet without reducing the ratio of the resin, and to obtain a bonded magnet having good mechanical properties such as strength.

[0004]

However, when only an epoxy resin which is liquid at room temperature is used as a binder, the powder fluidity of the composition to be subjected to press molding is reduced, so that the press molding becomes difficult and the mass productivity is reduced. A new problem has arisen that is severely impaired.

Accordingly, it is an object of the present invention to provide a bonded magnet composition having improved powder flowability without impairing magnetic properties and a method for producing the same. Another object of the present invention is to provide a bonded magnet obtained from the above composition.

[0006]

According to the present invention, 100 parts by weight of a magnetic alloy powder and 50 particles of particles having a particle size of 20 μm or less are used.
Silicon dioxide powder 0.01 to 5 parts by weight is the amount% or more, 7
The present invention provides a composition for a bonded magnet, comprising: a thermosetting resin having a kinematic viscosity (25 ° C.) according to the Gardner method in a 0% by weight butyl carbitol solution of 1 × 10 ⁻³ m ² / s or less.

According to the present invention, a magnetic alloy powder and 70 %
After mixing with a thermosetting resin having a kinematic viscosity (25 ° C.) of 1 × 10 ⁻³ m ² / s or less according to the Gardner method in a weight% butyl carbitol solution, a particle size of 20 μm or less is obtained.
Silicon dioxide powder having a particle size of 50% by weight or more
Provided is a method for producing a composition for a bonded magnet, characterized by mixing 0.01 to 5 parts by weight per 100 parts by weight of powder .

According to the present invention, 100 parts by weight of a magnetic alloy powder , 0.01 to 5 parts by weight of silicon dioxide powder having 50% by weight or more of particles having a particle size of 20 μm or less, and 70% by weight. After pressure-molding a composition for a bonded magnet containing a thermosetting resin having a kinematic viscosity (25 ° C.) of 1 × 10 ⁻³ m ² / s or less according to the Gardner method in a butyl carbitol solution, There is provided a method for producing a bonded magnet , which is characterized by being cured by heating.

Magnetic Powder In the present invention, as the magnetic powder, a magnetic alloy powder usually used for a bonded magnet can be used. Magnetic powder with an isotropic magnetic field (HA) of 50 kOe or more,
For example, rare earth cobalt-based magnetic powders such as Sm ₁ -Co ₅ system, Sm ₂ (CoFeZrV) ₁₇ system, Nd-Fe-Co-B system, Nd-Dy-
Rare earth-iron-boron based magnetic powders such as Fe-B based, Nd-Fe-B based, Sm-Fe-N based, Nd-Fe-Ti-N based, Nd-Fe-V-
It is desirable to use nitride-based magnetic powder such as N-based. In the present invention, it is preferable that the particle size of the magnetic powder is usually 35 mesh (JIS) or less.

[0010] Of the magnetic powders exemplified above, it is particularly preferable to use a rare earth-iron-boron magnetic powder obtained by a liquid quenching method. In this liquid quenching method, an alloy having a required composition is melted by a method such as high-frequency induction heating, and the obtained molten metal is sprayed onto a high-speed rotating copper or aluminum roll to be quenched, and a ribbon having a thickness of several tens of microns is formed. I do. The ribbon is subjected to an appropriate heat treatment, for example, to an average crystal grain size of 3000 ° or less, and then subjected to dry or wet pulverization using a stamp mill, a ball mill, or the like to obtain a desired magnetic powder.

[0011] Oite to the onset bright silicon dioxide powder, it is very important to use a specific silicon dioxide powder in combination with the magnetic powder. That is, after the above magnetic powder is mixed with a thermosetting resin described later, silicon dioxide powder having a particle size of 20 μm or less and 50% by weight or more is mixed with 0.01 to 5 parts by weight per 100 parts by weight of the magnetic alloy powder.
When parts mixed-exists in a state in which the silicon dioxide powder were dusted around the thermosetting resin coated with magnetic powder (which can be confirmed by electron microscopy), as a result of this, powder of magnet composition It is believed that fluidity is improved.

Examples of the silicon dioxide powder include fumed silica, calcined silica, precipitated silica, crushed silica,
Any one of fused silica and surface-treated silica obtained by treating these surfaces with an appropriate agent can be used, and these contain particles having a particle size of 20 μm or less at 50% by weight or more and a maximum particle size of 20 μm or less. There Ru Oh below the also because 200μm. 2
When the content of particles having a particle size of 0 μm or less is less than 50% by weight, it is necessary to use an extremely large amount of silicon dioxide powder in order to improve the powder fluidity of the composition. And the mechanical strength tends to decrease.

The amount of silicon dioxide powder to be used is
It is set in the range of 0.01 to 5 parts by weight, particularly 0.1 to 1 part by weight per 100 parts by weight. If less than 0.01 parts by weight,
If good powder fluidity cannot be obtained, and if it is used in an amount larger than 5 parts by weight, magnetic properties and mechanical strength will be reduced.

[0014] Although thermosetting resins at least one thermosetting resin is used as a binder, in the present invention, the thermosetting resin, 7
It is necessary that the kinematic viscosity (25 ° C.) of the 0% by weight butyl carbitol solution by the Gardner method is 1 × 10 ⁻³ m ² / s or less. That is, when the kinematic viscosity of the thermosetting resin is higher than 1 × 10 ⁻³ m ² / s, the powder fluidity of the composition for a bonded magnet is improved, but the molded product obtained by press molding described below is used. Therefore, voids are easily formed in the magnetic powder, and therefore the density of the magnetic powder cannot be improved, and the magnetic properties of the resulting bonded magnet become unsatisfactory.

In the present invention, as the thermosetting resin constituting the binder, various types can be used. For example, various types such as glycidyl ether type, glycidyl ester type, glycidylamine type, linear aliphatic epoxide type and the like can be used. Examples include various imide resins such as epoxy resin, aminobismaleimide, bismaleimide triazine, imide ether, phenylated imide thiophene, silicone-modified imide, and fluorine-containing imide, phenol resin, amino resin, diallyl phthalate resin, and unsaturated polyester resin. Can be. These can be used in combination of two or more as long as the kinematic viscosity described above is satisfied.

The above-mentioned thermosetting resin is made of the magnetic powder 10
It is preferred to use 0.5 to 5 parts by weight, especially 1 to 3 parts by weight, per 0 parts by weight. If the amount is more than 5 parts by weight, the magnetic properties of the bonded magnet are impaired, and if it is less than 0.5 parts by weight, the mechanical strength of the bonded magnet is impaired.

Other Components In the composition for a bonded magnet of the present invention, in addition to the above-mentioned essential components, if necessary, additives known per se, for example, a Si-based, Ti-based or Al-based chemically bonded surface A treating agent (coupling agent), a resin curing agent, a curing accelerator (curing catalyst) and the like can be used.

For example, typical examples of the chemical bonding type surface treating agent include vinyltriethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, −
(Β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane,
γ-glycidoxypropylmethyldimethoxysilane, γ
Methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate,
Isopropyl tri (N-aminoethyl-aminoethyl)
Titanate, tetraoctylbis (ditridecylphosphite) titanate, isopropyltrioctanoyl titanate, isopropyldimethacrylisostearoyl titanate, isopropyltridecylbenzenesulfonyl titanate, acetoalkoxyaluminum diisopropylate and the like can be exemplified. By mixing these by a dry method, a wet method, an integral blend method, or the like, the adhesion between the magnetic powders in the obtained bonded magnet can be improved.

Examples of the resin curing agent include a single polyamine type curing agent, a modified polyamine type curing agent, an acid anhydride type curing agent, a polyphenol type curing agent, a polymercaptan type curing agent, an anionic polymerization type curing agent, and a cationic polymerization type curing agent. A curing agent and the like can be exemplified. Examples of the curing accelerator include tertiary amines, imidazoles, organic metal salts, various chlorides, and organic peroxides. These resin curing agents and curing accelerators are used singly or in combination of two or more, depending on the type of thermosetting resin used as a binder.

Bonded magnet composition The bonded magnet composition of the present invention is obtained by mixing the above magnetic alloy powder and the above thermosetting resin having a specific kinematic viscosity ,
Thereafter, particles having a particle size of 20 μm or less account for 50% by weight or more.
Silicon dioxide powder the magnetic alloy powder 100 parts by weight per that
It is obtained by mixing 0.01 to 5 parts by weight . In this case, it is preferable that optional components such as various surface treatment agents, resin curing agents, and curing accelerators are mixed together with the thermosetting resin to finally mix the silicon dioxide powder. Thus, a state where the silicon dioxide powder was dusted into the thermosetting resin surface covering the magnetic alloy powder,
Good powder fluidity is ensured.

The mixing method of each component is not particularly limited, and examples thereof include a ribbon blender, a tumbler, a Nauter mixer,
The composition can be performed using a mixer such as a Henschel mixer or a super mixer, and the composition for a bonded magnet can be prepared using, for example, any of a wet method and a dry method. The wet method is a method of dissolving an organic component such as a thermosetting resin serving as a binder in a suitable organic solvent such as methyl ethyl ketone, mixing this with a magnetic powder, drying, and then mixing a silicon dioxide powder to obtain a composition. It is. The dry method is
This is a method of preparing a composition by mixing components other than the silicon dioxide powder at once using the above-described mixer or the like and then mixing the silicon dioxide powder. Thus bonded magnet composition obtained, since the silicon dioxide powder is dusted on by using a thermosetting resin having a specific kinematic viscosity as <br/> binder, moreover thermosetting resin surface, A powdery composition having no tackiness and extremely high fluidity is obtained.

Bonded Magnet The bonded magnet of the present invention comprises 100 parts by weight of a magnetic alloy powder and particles.
Silicon dioxide powder in which particles having a diameter of 20 μm or less are 50% by weight or more
A kinematic viscosity (25 ° C.) of 0.01 to 5 parts by weight and 70% by weight butyl carbitol solution by the Gardner method is 1 × 10 ⁻³ m
^The composition for bonded magnets containing a thermosetting resin of ² / s or less is press-molded using various compression molding machines, and then heat-treated to cure the thermosetting resin. by magnetizing in a magnetic field, the manufacturing
It is concrete to Rukoto. Press molding is usually 4.0-8.0
The heat treatment is performed under a pressure of t / cm ² , and generally varies depending on the type of thermosetting resin used, but is generally 120 to 190 ° C.
At a temperature of 0.5 to 3 hours. Magnetization in a magnetic field can be performed simultaneously with press molding, for example. The bond magnet thus obtained has a high density and high magnetic properties, and also has excellent mechanical properties such as strength.

[0023]

EXAMPLES In the following examples, the following materials were used as materials for bonded magnets.

Magnetic powder Magnetic powder 1: Nd-Fe-B magnet powder (trade name: MQP-
B, manufactured by General Motors, USA), anisotropic magnetic field: 70.4
kOe, average particle size: 200 μm Magnetic powder 2: Sm · Co ₅ magnet powder (trade name: RCo ₅ alloy,
Sumitomo Metal Mining Co., Ltd.), Anisotropic magnetic field: 246kOe, average particle size: 10μm

Thermosetting resin Bisphenol A type epoxy resin Product name: Araldite GY260, manufactured by Nippon Ciba Geigy Co., Ltd. (completely liquid at 25 ° C.) Bisphenol A type epoxy resin Product name: Araldite GY280, manufactured by Nippon Ciba Geigy Co., Ltd. (25 ° C. At the same temperature, the kinematic viscosity in a 70% by weight butyl carbitol solution by the Gardner method is ^{4 to} 6.27 × 10 ⁻⁴ m ² / s) Cresol novolac type epoxy resin Trade name: Araldite ECN1273, Nippon Ciba Geigy Co., Ltd. Company (solid at 25 ° C) Bismaleimide triazine resin Product name: BT3109, manufactured by Mitsubishi Gas Chemical Co., Ltd. (Completely liquid at 25 ° C)

Silicon dioxide powder a) Trade name: Nip Seal SS-50, manufactured by Nippon Silica Industry Co., Ltd. Content of particles having a particle size of 20 μm or less: 100% by weight Average particle diameter: 1-2 μm, maximum particle diameter: 10 μm b) Trade name : Syloid # 150, manufactured by Fuji Devison Chemical Co., Ltd. Content of particles of 20 μm or less: 100% by weight Average particle size: 1.4 μm, Maximum particle size: 10 μm

Hardener 4,4'-diaminodiphenyl sulfone Trade name: Sumicur S, manufactured by Sumitomo Chemical Co., Ltd.

Examples 1 to 10 and Comparative Examples 1 to 4 According to the formulation shown in Tables 1 to 3, a solution obtained by diluting a thermosetting resin and a curing agent by 10 times with methyl ethyl ketone was added to the magnetic powder and mixed. Stirred. Next, at 30 ° C., methyl ethyl ketone was completely volatilized under reduced pressure (10 ⁻¹ Torr), silicon dioxide powder was further added according to the formulation shown in Tables 1 to 3, and mixing and stirring were performed again.
The desired bonded magnet composition was obtained. In each of the compositions of each example, only the thermosetting resin used,
The kinematic viscosity of a 70% by weight butyl carbitol solution was measured at 25 ° C. by the Gardner method, and the measured value was 1 × 10 ⁻³ m ² / s
Tables 1 to 3 show the following items as ○, and those with higher than 1 × 10 ⁻³ m ² / s as ×. Examples and Comparative Examples 1,
The compositions obtained in 2 and 3 were smooth and rich in fluidity, but the composition of Comparative Example 4 showed tackiness that easily aggregated. The powder fluidity of each composition was measured as follows, and the results are shown in Tables 1 to 3. Measurement of powder flowability: Using a composition in a mold (outer diameter 20 mmφ, inner diameter 18
(mmφ, depth 35 mm) and rubbed off, then the amount of powder in the mold was weighed. ○ When the amount of powder is 3g or more ○, 2g or more 3g
Less than △ and less than 2 g were judged as x.

Each of the compositions obtained above was supplied into a press die, and press-molded at a molding surface pressure of 5.7 ton / cm ² , and was vertically 80 mm long.
A plate-shaped sample having a width of 10 mm and a thickness of 4 mm was obtained (the composition using the magnetic powder 2 was molded in a magnetic field). Next, this plate-shaped sample was subjected to a heat treatment at 180 ° C. for 2 hours in the air, and the binder in the sample was cured to obtain a bonded magnet. The magnetic properties of the resulting bonded magnet were measured at room temperature using a thiophy-type self-recording magnetometer, and the measurement results were shown in Table 1.
To 3.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

In the above table, the numerical values in the formulation are as follows:
Parts by weight.

[0034]

Industrial Applicability The composition for a bonded magnet of the present invention not only has excellent magnetic properties of the magnet obtained, but also has extremely good powder fluidity, excellent molding workability, and high productivity. It has advantages and is very suitable for mass production.
Bond magnets obtained from this composition can be used in general home appliances,
The application range is expected to expand in a wide range of fields including communication and audio equipment, medical equipment, and general industrial equipment.

Claims (4)

(57) [Claims] 1. Kinematic viscosity by a Gardner method in a 70% by weight butyl carbitol solution, 100 parts by weight of a magnetic alloy powder, 0.01 to 5 parts by weight of silicon dioxide powder having 50% by weight or more of particles having a particle size of 20 μm or less. A thermosetting resin having a temperature of 25 ° C.) of 1 × 10 ⁻³ m ² / s or less. 2. The bonded magnet according to claim 1, wherein the magnetic alloy powder is coated with a thermosetting resin, and the silicon dioxide powder is present in a state of being covered with the thermosetting resin. Composition. 3. After mixing the magnetic alloy powder and a thermosetting resin having a kinematic viscosity (25 ° C.) of 1 × 10 ⁻³ m ² / s or less by a Gardner method in a 70% by weight butyl carbitol solution, A method for producing a composition for a bonded magnet, comprising mixing 0.01 to 5 parts by weight of silicon dioxide powder having 50% by weight or more of particles having a particle diameter of 20 μm or less per 100 parts by weight of the magnetic alloy powder. 4. 100 parts by weight of a magnetic alloy powder and a particle size of 20 μm
Silicon dioxide powder in which the following particles are at least 50% by weight: 0.01 to 5
A composition for bonded magnets containing a weight part and a thermosetting resin having a kinematic viscosity (25 ° C.) by a Gardner method of 1 × 10 ⁻³ m ² / s or less in a 70% by weight butyl carbitol solution. It is characterized by heat-curing after pressure molding .
Manufacturing method of that bond magnet.