JPH06231918A - Composition for bond magnet and its manufacture - Google Patents

Abstract

PURPOSE:To raise the fluidity of powder by using thermosetting resin binder, which has specified kinematic viscosity and besides whose surface is covered with urea radical compound powder. CONSTITUTION:Magnetic alloy powder and a binder, which consists of at least one kind of thermosetting resin and in which the kinematic viscosity (25 deg.C) by the Gardner method in 70wt.% butylcarbinol solution is 1X10<-3>m<2>s or under, are mixed. This is the manufacture of a composition for a bond magnet, which mixes 0.01-5 pts.wt. of urea radical compound [long-chained or circular hydrocarbon compounds containing urea radicals (-NHCONH-or-NHCOHH2) and having alkyl or olefin double coupling] per 100 pts.wt. of magnetic alloy powder into this mixture next. Furthermore, this is a bond magnet being obtained heating and hardening it after pressurization of this composition for molding. Hereby, a composition for a bond magnet, where the powder fluidity is improved without marring the magnetic property, and a bond magnet favorable in magnetic property and mechanical property can be obtained.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Due to their excellent magnetic properties, rare earth permanent magnets are being used in a wide range of fields including general household electric appliances, communication / audio equipment, medical equipment, and general industrial equipment. Among them, the bond type magnet is one in which a magnetic powder is mixed with a resin binder and press-molded. Therefore, (1) dimensional accuracy is high and a complicated shape can be formed as compared with a sintered type magnet. The advantages are (2) high uniformity of quality and performance, (3) good yield and good machinability. However, on the other hand, since a resin binder is used, the magnetic properties of the magnet are impaired.

Recently, a bonded magnet obtained by using an epoxy resin which is liquid at room temperature as a resin binder, which satisfies the contradictory requirements of improving the magnetic properties and mechanical properties of the magnet. Is proposed. That is, by using such an epoxy resin, it is possible to improve the magnetic properties of the magnet without suppressing the ratio of the resin to a low level, and it is possible to obtain a bonded magnet having good mechanical properties such as strength.

[0004]

However, when only the epoxy resin which is liquid at room temperature is used as the binder, the powder fluidity of the composition to be press-molded is lowered and the press-molding becomes difficult, resulting in mass productivity. There is a new problem that is greatly damaged.

Therefore, an object of the present invention is to provide a composition for a bonded magnet having improved powder fluidity 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
By weight of a magnetic alloy powder, 0.01 to 5 parts by weight of a urea-based compound powder, and at least one thermosetting resin and having a kinematic viscosity (25 ° C.) in a 70 wt% butyl carbitol solution by the Gardner method. Provided is a composition for a bonded magnet, which contains a binder of 1 × 10 ⁻³ m ² / s or less. However, the urea group compound means a urea group (-N
HCONH-, or includes -NHCONH _2), having an alkyl or olefinic double bonds, it refers to a long chain or cyclic hydrocarbon compound.

Further, according to the present invention, the kinematic viscosity (25 ° C.) by the Gardner method in a 70 wt% butyl carbitol solution, which comprises magnetic alloy powder and at least one thermosetting resin, is 1 × 10 ⁻³ m. Provided is a method for producing a composition for a bonded magnet, which comprises mixing 0.01 to 5 parts by weight of a urea group compound per 100 parts by weight of the magnetic alloy powder after mixing with a binder having a ratio of ² / s or less. To be done.

According to the present invention, there is further provided a bond magnet obtained by pressure-molding the composition for a bond magnet and then heat-curing the composition.

[0009]

[Action]

A. Magnetic Powder As the magnetic powder in the present invention, a magnetic alloy powder usually used in bonded magnets can be used,
In order to obtain a bonded magnet with more excellent magnetic properties, magnetic powders having an anisotropic magnetic field ( _HA ) of 50 kOe or more, for example, Sm-Co ₅ system, Sm ₂ (Co, Fe, Z) are particularly preferable.
r, V) _17- based rare earth cobalt-based magnetic powder, Nd-
Fe-Co-B system, Nd-Dy-Fe-B system, Nd-Fe-B
Rare earth-iron-boron magnetic powder, Sm-Fe-N system, N
It is desirable to use a d-Fe-Ti-N-based or Nd-Fe-VN-based nitride-based magnetic powder. Further, in the present invention, it is desirable that the particle size of the above-mentioned magnetic powder is usually less than the total size of JIS sieve # 35.

Among the magnetic powders exemplified above, rare earth elements
As the iron-boron magnetic powder, it is particularly preferable to use the one obtained by the liquid quenching method. In this liquid quenching method, an alloy of the required composition is melted by a method such as high-frequency induction heating, and the resulting melt is sprayed onto a high-speed rotating copper or aluminum roll to be rapidly cooled to form a ribbon with a thickness of several tens of μm. To do. Next, after subjecting this ribbon to an appropriate heat treatment, for example, to reduce the average crystal grain size to 3000 A or less,
The target magnetic powder is obtained by dry or wet pulverization using a stamp mill, a ball mill or the like.

B. Urea-Based Compound Powder In the present invention, it is extremely important to use the urea-based compound powder in combination with the above magnetic powder. That is,
When the above-mentioned magnetic powder is mixed with the binder described below and then the urea-based compound powder is mixed therein, the urea-based compound powder exists in a state of being sprinkled around the binder coated with the magnetic powder (this is confirmed by an electron microscope. It is believed that the powder fluidity of the magnet composition is improved as a result. Here, as described above, the urea group (-NHC
ONH-, or includes -NHCONH _2), having an alkyl or olefinic double bonds, that long-chain or cyclic hydrocarbon compound urea group compound.

Examples of such urea group compound powders include N-butyl-N'-stearyl urea, N-hexyl-N'-stearyl urea, N-octyl-N'-stearyl urea, and N-hexadecane-N'-. Stearyl urea,
Cis-9-cis-12-octadecadiene-N'-stearyl urea, 9,12,15-octadecatriene-N
′ -Stearylurea, N-phenyl-N′-stearylurea, N-stearyl-N′-stearylurea, N-butyl-N′-laurylurea, N-hexyl-N′-laurylurea, N-octyl-N ′ -Laurylurea, N-hexadecane-N′-laurylurea, cis-9-cis-1
2-octadecadiene-N'-lauryl urea, 9,1
2,15-octadecatriene-N'-lauryl urea,
N-phenyl-N'-lauryl urea, N-stearyl-
N'-lauryl urea, xylene bis stearyl urea, toluylene bis stearyl urea, hexamethylene bis stearyl urea, diphenylmethane bis stearyl urea, xylene bis lauryl urea, toluylene bis lauryl urea, hexamethylene bis lauryl urea, diphenyl methane bis lauryl urea, etc. Powders, and these can be used alone or in combination of two or more.

The amount of the urea-based compound powder used is set in the range of 0.01 to 5 parts by weight, particularly 0.1 to 2 parts by weight, per 100 parts by weight of the magnetic powder. If it is less than 0.01 part by weight, good powder fluidity cannot be obtained, and if it is used in excess of 5 parts by weight, magnetic properties are deteriorated.

C. Binder At least one kind of thermosetting resin is used as a binder. In the present invention, this binder has a kinematic viscosity (25 ° C.) of 70% by weight butyl carbitol solution by Gardner method of 1 × 10 ⁻³ m ² It is necessary to be less than / s. A single resin, a mixed resin of liquid materials, a mixed resin of a liquid material and a solid material, and the like can be used as long as they finally satisfy this kinematic viscosity. When the kinematic viscosity of the binder is higher than 1 × 10 ⁻³ m ² / s, the powder fluidity of the composition for a bonded magnet is improved, but the friction resistance of the magnetic powder is remarkably increased, which is obtained by press molding described later. Voids are easily generated in the formed body. Therefore, the density of the bonded magnet cannot be improved, and the magnetic properties of the resulting bonded magnet become unsatisfactory.

In the present invention, various kinds of thermosetting resins can be used as the thermosetting resin constituting the binder. Examples thereof include glycidyl ether type, glycidyl ester type, glycidyl amine type, linear aliphatic epoxide type,
Various epoxy resins such as aliphatic epoxide type, amino bismaleimide, bismaleimide triazine, imide ether, phenylated imide thiophene, silicone modified imide, various imide resins such as fluorinated imide, phenol resin, amino resin, diallyl phthalate resin, A saturated polyester resin etc. can be illustrated. They are,
As long as the above-mentioned kinematic viscosity is satisfied, two or more kinds can be used in combination.

The above-mentioned binder is the above-mentioned magnetic powder 10
It is preferably used in an amount of 0.5 to 5 parts by weight, especially 1 to 3 parts by weight, per 0 parts by weight. If it is used in an amount of more than 5 parts by weight, the magnetic properties of the bonded magnet will be impaired, and if it is less than 0.5 part by weight, the mechanical strength of the bonded magnet will be impaired.

D. Other Components In the composition for a bonded magnet of the present invention, in addition to the above-mentioned essential components, if necessary, an additive known per se, for example, a Si-based, Ti-based or Al-based chemically bonded surface treatment agent ( A coupling agent), a resin curing agent, a curing accelerator (curing catalyst), etc. can be used. For example, as typical ones of the above chemical bond type surface treatment agents, vinyltriethoxysilane, γ-aminopropyltriethoxysilane, N-
(Β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, isopropyltriisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethyl) -Aminoethyl) titanate, tetraoctyl bis (ditridecyl phosphite) titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropylt Decyl benzene sulfonyl titanate, it may be exemplified acetoalkoxyaluminum diisopropylate. By mixing these by a dry method, a wet method, an integral blending method, or the like, it is possible to improve the adhesion between the magnetic powders in the obtained bonded magnet.

Examples of the resin curing agent, the crosslinking agent, the reaction initiator, and the reaction accelerator include a single polyamine type curing agent, a modified polyamine type curing agent, an acid anhydride type curing agent, a polyphenol type curing agent, and a polymercaptan type curing agent. , Anionic polymerization type curing agent, cationic polymerization type curing agent, styrene and its derivatives, diallyl phthalate, triallyl isocyanurate, various organic peroxides, tertiary amine acids, imidazoles, organometallic salts, chlorides, etc. It can be illustrated. These resin curing agents, cross-linking agents, reaction initiators, and reaction accelerators may be used alone or in combination of two or more, depending on the type of thermosetting resin used as a binder.

E. Composition for Bonded Magnet The composition for bonded magnet of the present invention is obtained by mixing the above-mentioned magnetic alloy powder and a binder, and then mixing the urea-based compound powder. In this case, it is preferable that optional components such as various surface treatment agents, resin curing agents, and curing accelerators are mixed with the binder, and finally the urea group compound powder is mixed. As a result, the urea-based compound powder is sprinkled on the surface of the binder that coats the magnetic alloy powder, and good powder fluidity is ensured.

The mixing method of each component is not particularly limited, for example, a ribbon blender, a tumbler, a Nauter mixer,
The composition for a bonded magnet can be prepared by using a mixer such as a Henschel mixer or a super mixer, and by using either a wet method or a dry method. In the wet method, an organic component such as a thermosetting resin serving as a binder is dissolved in an appropriate organic solvent such as methyl ethyl ketone, mixed with magnetic powder and dried, and then a urea-based compound powder is mixed to obtain a composition. Is the way. The dry method is a method in which the components other than the urea group compound powder are collectively mixed using the above-mentioned mixer and the like, and then the urea group compound powder is mixed to prepare a composition.

The bond magnet composition thus obtained is
Since the thermosetting resin binder having a specific kinematic viscosity is used and the binder surface is sprinkled with the urea group compound powder, the powdery composition has no tackiness and extremely high fluidity.

F. Bonded magnet The composition for a bonded magnet described above is obtained by press-molding using various compression molding apparatuses, followed by heat treatment to harden the binder, and then magnetizing the binder magnet in a magnetic field, if necessary. Can be obtained. Press molding is usually performed under a pressure of 4 to 8 t / cm ² ,
The heat treatment is generally performed at a temperature of 200 ° C. or lower for 0.5 to 24 hours, although it varies depending on the type of binder used, the curing agent, the crosslinking agent, the curing accelerator, and the polymerization initiator. Magnetization in a magnetic field can also be performed simultaneously with press molding, for example. The bond magnet thus obtained has a high density and high magnetic properties, and is also excellent in mechanical properties such as strength.

[0023]

EXAMPLES In the following examples, the following were used as the composition for bonded magnets and the materials for bonded magnets. I 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 Magnetic powder 2: Sm-Co ₅ type magnetic powder (trade name: RCo ₅ alloy, Sumitomo Metal Mining Co., Ltd.) Anisotropic magnetic field: 246 kOe , Average particle size 10 μm

II Thermosetting resin i) Bisphenol A type epoxy resin (trade name: Araldite GY260, manufactured by Ciba-Geigy Co., Ltd.) ii) Bisphenol A epoxy resin (trade name: Araldite GY280, manufactured by Ciba-Geigy Co., Ltd.) iii) Cresol novolac type epoxy resin (trade name:
Araldite ECN1273, manufactured by Nippon Ciba-Geigy Co., Ltd. iv) Bismaleimide triazine resin (trade name: BT
-3109, manufactured by Mitsubishi Gas Chemical Co., Inc.)

III Urea group compound a) N-butyl-N'-stearyl urea (trade name: HCL Clean SB, manufactured by Nippon Kasei Co., Ltd.) b) Diphenylmethanebislauryl urea (trade name: HCL Clean LM, manufactured by Nihon Kasei Co., Ltd.)

IV curing agent 4,4'-diaminodiphenyl sulfone (trade name: Sumicure-S, manufactured by Sumitomo Chemical Co., Ltd.) V stearic acid stearic acid (manufactured by Kanto Chemical Co., Inc.)

Examples 1 to 12 and Comparative Examples 1 to 5 According to the formulations shown in Tables 1 to 3, a solution prepared by diluting a thermosetting resin and a curing agent by 10 times with methyl ethyl ketone was added to magnetic powder and mixed and stirred. . Then, at 30 ° C., methyl ethyl ketone was completely volatilized under reduced pressure (10 ⁻¹ Torr), urea compound powder was further added according to the formulation shown in Tables 1 to 3, and the mixture was stirred again to obtain a desired bond magnet. A composition for use was obtained.

In each of the compositions of the examples, only the thermosetting resin used was measured for kinematic viscosity at 25 ° C. in a 70 wt% butyl carbitol solution by the Gardner method, and the measured value was 1 × 10 ^-3 m ^2. / S or less is ○,
Those higher than 1 × 10 ⁻³ m ² / s are marked with x, and Table 1
The results are shown in Table 3. The compositions obtained in Examples and Comparative Examples 3 to 5 were free-flowing and rich in fluidity, but the compositions of Comparative Examples 1 and 2 exhibited tackiness that easily aggregated. .

The powder fluidity of each composition was measured, and the results are shown in Tables 1 to 3. To measure the powder fluidity, mold the composition (outer diameter 20 mm, inner diameter 18 mm, depth 35 mm).
After powdering and scraping off, the amount of powder in the mold was evaluated, and the amount of 3 g or more was evaluated as ◯, 2 g or more and less than 3 g as Δ, and less than 2 g as x.

Each composition obtained above was fed into a press mold and press-molded at a molding surface pressure of 5.7 t / cm ² to obtain a plate sample having a length of 80 mm, a width of 10 mm and a thickness of 4 mm. .
The composition using the magnetic powder 2 was molded in a magnetic field. Next, this plate-shaped sample was placed in the atmosphere at 180 ° C x 2
Heat treatment was carried out for a period of time to cure the binder in the sample to obtain a bonded magnet. The magnetic properties of the obtained bonded magnet are
The measurement was performed at room temperature using a Thiophie type self-recording magnetometer, and the measurement results are shown in Tables 1 to 3. The magnetic properties of the bonded magnet require that the maximum magnetic energy product be 11 MGOe or more.

Similarly, each of the compositions obtained above is fed into a press die and press-molded at a molding surface pressure of 5.0 t / cm ² , and a ring having an outer diameter of 34 mm, an inner diameter of 32 mm, and a height of 8 mm. A sample was obtained. Only the composition using the magnetic powder 2 was molded in a magnetic field. Next, this ring-shaped sample was heat-treated in the air at 180 ° C. for 2 hours to cure the binder in the sample to obtain a bonded magnet. The fracture strength of the obtained bonded magnet was crushed using an autograph manufactured by Shimadzu Corporation under the conditions of a head speed of 1 mm / min and room temperature to measure the maximum fracture strength. The results are shown in Tables 1 to 3. The maximum ring breaking strength of the bonded magnet needs to be 3 kgf or more. In the above table, the numerical values in the formulation are parts by weight.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

From the above results, the composition for a bonded magnet of the present invention is excellent in powder fluidity, and the bonded magnet using this composition for a bonded magnet is excellent in both magnetic properties and breaking strength. Recognize.

[0036]

The composition for bonded magnets of the present invention has the advantages that not only the magnetic properties of the obtained magnets are excellent, but also the powder flow properties are extremely good, the moldability is excellent, and the productivity is high. It is extremely suitable for mass production. The bonded magnet obtained from this composition is expected to have a wide range of applications in a wide range of fields including general home appliances, communication / audio equipment, medical equipment, and general industrial equipment.

Claims (4)

[Claims] 1. A magnetic alloy powder of 100 parts by weight and 0.0
1 to 5 parts by weight of a urea-based compound powder and at least one thermosetting resin and having a kinematic viscosity (25 ° C.) by a Gardner method in a 70% by weight butyl carbitol solution of 1 × 10 ⁻³ m ² / s. A composition for a bonded magnet, which comprises the following binder. However, the urea group compound is a urea group (-NHCONH- or -NHCONH
₂ ) long-chain or cyclic hydrocarbon compounds containing alkyl or olefinic double bonds. 2. The composition for a bonded magnet according to claim 1, wherein the magnetic alloy powder is coated with a binder, and the urea-based compound powder is present in a state of being sprinkled on the surface of the binder. 3. A magnetic alloy powder and at least one thermosetting resin, and the kinematic viscosity (25 ° C.) by a Gardner method in a 70 wt% butyl carbitol solution is 1 ×.
After mixing with a binder that is 10 ⁻³ m ² / s or less,
A method for producing a composition for a bonded magnet, which comprises mixing 0.01 to 5 parts by weight of a urea-based compound per 100 parts by weight of the magnetic alloy powder. 4. 100 parts by weight of magnetic alloy powder and 0.01
.About.5 parts by weight of a urea group compound and at least one thermosetting resin, and has a kinematic viscosity (25.degree. C.) by a Gardner method in a 70% by weight butyl carbitol solution of 1.times.1.
A bond magnet obtained by subjecting a composition for a bond magnet containing a binder having a content of 0 ^-3 m ² / s or less to pressure molding and then heat curing.