JP3185458B2 - Composition for resin-bonded magnet, resin-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 resin-bonded magnet composition excellent in moldability and a resin-bonded magnet obtained from the composition and having excellent magnetic properties.

[0002]

2. Description of the Related Art Rare earth permanent magnets are being used in a wide range of fields from general household electric appliances, communication / audio equipment, medical equipment, and general industrial equipment due to their excellent magnetic properties. Among them, resin-bonded magnets are formed by press molding by mixing a resin binder with magnetic powder, so (1) compared to sintered magnets, they can be molded into a complicated shape with high dimensional accuracy. 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.

[0003] Recently, a resin that can satisfy the contradictory requirements of improving magnetic properties and mechanical properties of a magnet can be obtained by using a single liquid epoxy resin at room temperature as a resin binder. Resin-bonded 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 a resin-bonded magnet having good mechanical properties such as strength can be obtained. is there.

[0004]

However, when only an epoxy resin which is liquid at normal temperature is used as a binder, the powder fluidity of the composition to be subjected to press molding is reduced, so that press molding becomes difficult and mass production becomes difficult. Has a new problem that is greatly impaired.

Accordingly, an object of the present invention is to provide a resin-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 resin-bonded magnet obtained from the above composition.

[0006]

According to the present invention, there is provided a magnetic coupling device comprising:
Gold powder and at least bisphenol A epoxy resin
And two novolak epoxy resins
Composed of phenol and aromatic amine epoxy resin curing agent
And silicon dioxide, urea group (-NHCONH-,
Is a saturated aliphatic hydrocarbon including -NHCONH _2), fat
Any one of a cyclic hydrocarbon and an aromatic hydrocarbon or
Urea group compounds and amides composed of two or more kinds
Group (-CONH-, or, -CONH ₂₎ saturated containing
Of aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons
Amides composed of any one or more of them
Powder of one kind of lubricant selected from the group consisting of base compounds
The composition for a resin-bonded magnet containing
Is a guard in 70% by weight butyl carbitol solution
The kinematic viscosity (25 ° C.) by the toner method is 1 × 10 ⁻³ m ² / s
The following, the lubricant powder is formed on the magnetic alloy powder surface
Exists on the surface of the binder film
And a composition for a resin-bonded magnet. Also, according to the present invention, in the above invention,
The amount of the binder is 0.1 to 100 parts by weight of the magnetic alloy powder.
5 to 5 parts by weight, and the addition amount of silicon dioxide or the like is
0.01 to 5 parts by weight per 100 parts by weight of magnetic alloy powder
A composition for a resin-bonded magnet, characterized in that
It is.

Further, according to the present invention, in the above invention,
After mixing with a magnetic alloy powder, a binder, dioxide
A method for producing a composition for a resin-bonded magnet, characterized by mixing silicon or the like is provided.

According to the present invention, there is further provided a resin-bonded magnet obtained by press-molding and heat-curing the resin-bonded magnet composition of the present invention.

[0009]

[Action]

A. Magnetic powder In the present invention, as the magnetic powder, a magnetic alloy powder usually used for a resin-bonded magnet can be used, but in order to obtain a resin-bonded magnet having more excellent magnetic properties, among them, Magnetic powder having an anisotropic magnetic field (H _A ) of 50 kOe or more, for example, Sm—Co ₅ system, Sm ₂ (Co,
Fe, Zr, V) Rare earth cobalt-based magnetic powder such as _17- based, Nd-Fe-Co-B-based, Nd-Dy-Fe-B-based, Nd
-Fe-B and other rare earth-iron-boron magnetic powders, Sm-Fe-
It is desirable to use N-based, Nd-Fe-Ti-N-based, Nd-Fe-V-N-based nitride-based magnetic powders and the like. In the present invention, the particle diameter of the magnetic powder is generally desirably not more than the entire JIS sieve # 35.

Of the magnetic powders exemplified above, it is particularly preferable to use 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 μm is formed. I do. After performing an appropriate heat treatment on the ribbon, for example, to reduce the average crystal grain size to 3000 A or less,
The intended magnetic powder is obtained by performing dry or wet pulverization using a stamp mill, a ball mill or the like.

B. Silicon Dioxide Powder In the present invention, it is extremely important to use a powder such as silicon dioxide in combination with the above magnetic powder. That is, when the above magnetic powder is mixed with a binder described later and then mixed with a powder such as silicon dioxide, the powder becomes a magnetic powder.
The surface of the binder film formed on the rear surface is in a state of being dusted. This can be confirmed by an electron microscope. As a result, it is considered that the powder fluidity of the composition for magnet is improved.

Examples of the silicon dioxide powder include fumed silica, calcined silica, precipitated silica, pulverized silica,
Any material such as fused silica and surface-treated silica obtained by treating these surfaces with an appropriate agent can be used. Generally, those containing 50% or more of particles having a particle size of 20 μm or less are used. In particular, those having a maximum particle size of 200 μm or less or an average particle size of 10 μm or less are preferable, and those having an average particle size of 5 μm or less are most preferable. For example, when the content of particles having a particle size of 20 μm or less is less than 50%, it is necessary to use a very large amount in order to improve the powder fluidity of the composition. Tends to decrease.

C. Urea-based compound powder As the urea-based compound powder, for example, N-butyl-
N'-stearyl urea, N-hexyl-N'-stearyl urea, N-octyl-N'-stearyl urea, N-hexadecane-N'-stearyl urea, cis-9-cis-
12-octadecadien-N'-stearyl urea, 9,
12,15-octadecatriene-N'-stearyl urea, N-phenyl-N'-stearyl urea, N-stearyl-N'-stearyl urea, N-butyl-N'-lauryl urea, N-hexyl-N ' -Lauryl urea, N-octyl-N'-lauryl urea, N-hexadecane-N '
-Lauryl urea, cis-9-cis-12-octadecadien-N'-lauryl urea, 9,12,15-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, diphenyl methane bis stearyl urea, xylene bis lauryl urea, toluylene bis lauryl urea, hexamethylene bis Powders such as lauryl urea and diphenylmethanebislauryl urea are mentioned, and these can be used alone or in combination of two or more.

D. Amide group compound powder Examples of the amide group compound powder include, for example, saturated fatty acid monoamide, unsaturated fatty acid monoamide, substituted amides, methylol amides, saturated fatty acid bisamide, unsaturated fatty acid bisamide, aromatic bisamide, and the like. More specifically, examples of the saturated fatty acid monoamide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide, and unsaturated fatty acid monoamides include oleic acid amide, erucic acid amide, and ricino-amide. Examples of substituted amides such as oleic acid amide include N-stearylstearic acid amide, N-oleyloleic acid amide, N-stearyloleic acid amide, N-oleylstearic acid amide, and N-sulfuric acid amide. Examples of methylol amides such as amide tearyl erucate and amide N-oleyl palmitate are methylo-amides.
Examples of saturated fatty acid bisamides such as rustearic acid amide and methylo-rubehenic acid amide include methylene bisstearic acid amide, methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bis stearic acid amide, ethylene bis Isostearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearic acid amide, hexamethylenebisbehenic acid amide, hexamethylenebishydroxystearic acid amide, N, N '
Unsaturated fatty acid bisamides such as distearyl adipate amide, N, N′-distearyl sebacate amide, etc., include ethylene bisoleate amide, hexamethylene bisoleate amide, N, N′-dioleyl adipamide, N , N'-dioleyl sebacin amide and the like, aromatic bisamides such as m-xylene bisstearic acid amide, N, N'-distearyl isophthalic acid amide and other powders;
These can be used alone or in combination of two or more.

The amount of the powder such as silicon dioxide used is 0.01 to 5 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of the magnetic powder.
It is set in the range of 1 to 2 parts by weight. If less than 0.01 parts by weight, good powder fluidity cannot be obtained,
If used in an amount larger than 5 parts by weight, the magnetic properties will be reduced. Note that two or more of silicon dioxide powder, urea-based compound powder, and amide-based compound powder may be used as a mixture.

E. Binder As the binder, one composed of at least two types of epoxy resin base agents, bisphenol A type epoxy resin and novolak type epoxy resin, and an aromatic amine type epoxy resin curing agent is used. In the present invention, the binder is 70% by weight. It is necessary that the kinematic viscosity (25 ° C.) of the butyl carbitol solution measured by the Gardner method is 1 × 10 ⁻³ m ² / s or less. As long as it finally satisfies the kinematic viscosity, any of a single resin, a mixed resin of liquid substances, a mixed resin of a liquid substance and a solid substance, and the like can be used.
When the kinematic viscosity of the binder is higher than 1 × 10 ⁻³ m ² / s, the powder fluidity of the resin-bonded magnet composition is improved, but the frictional resistance of the magnetic powder is significantly increased. Thus, voids are likely to be formed in the obtained molded article. Therefore, the density of the resin-bonded magnet cannot be improved, and the resulting magnetic properties of the resin-bonded magnet are unsatisfactory.

In the present invention, in addition to at least two types of epoxy resin base agents, ie, bisphenol A type epoxy resin and novolak type epoxy resin, and an aromatic amine type epoxy resin curing agent, other thermosetting resins (others) may be used. Epoxy resins of the type described above) and curing agents, for example, various epoxy resins such as glycidyl ether type, glycidyl ester type, glycidylamine type, linear aliphatic epoxide type, aliphatic epoxide type, amino Examples include various imide resins such as bismaleimide, bismaleimide triazine, imide ether, phenylated imidothiophene, silicone modified imide, and fluorinated imide, phenol resin, amino resin, diallyl phthalate resin, and unsaturated polyester resin. These may be used in combination of two or more as long as the kinematic viscosity described above is satisfied.

The binder described above is used for 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 used in an amount greater than 5 parts by weight, the magnetic properties of the resin-bonded magnet will be impaired,
If the amount is less than 0.5 parts by weight, the mechanical strength of the resin-bonded magnet is impaired.

F. Other components In the resin-bonded magnet composition of the present invention, in addition to the above essential components, if necessary, additives known per se,
For example, a Si-based, Ti-based or Al-based chemical bond type surface treatment agent (coupling agent), a curing accelerator (curing catalyst), or the like can be used. For example, typical examples of the chemical bonding type surface treatment agent include vinyltriethoxysilane, γ-aminopropyltriethoxysilane, N- (β-
(Aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-gly Sidoxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane,
γ-methacryloxypropylmethyldimethoxysilane,
Isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, tetraoctyl bis (ditridecyl phosphite) titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearyl 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 magnetic powders in the obtained resin-bonded magnet can be improved.

G. Curing Agent In the present invention, it is extremely important to use an aromatic amine-based curing agent in combination with the magnetic powder, powder such as silicon dioxide, and an epoxy resin binder having a specified viscosity or less. That is, when an epoxy resin binder having a specified viscosity or less and an aromatic amine-based curing agent described below are mixed, it is considered that as a result, the mechanical strength of the magnet composition is improved.

Examples of the aromatic amine curing agent include m-phenylenediamine, p, p'-diaminodiphenylmethane, p, p'-diaminodiphenylsulfone, metaxylenediamine, xylenediamine, and 1,3.
Any curing agent generally referred to as aromatic polyamine or aromatic amine, such as -bis (aminomethyl) cyclohexane, can be used, and of course, modified products thereof can also be used. The above-mentioned aromatic amine-based curing agents are different in epoxy equivalent and active hydrogen equivalent depending on the kind of the epoxy resin and the kind of the aromatic amine-based curing agent. Specifically, 0.01 to 1 per 100 parts by weight of the magnetic powder.
It is preferred to use 0 parts by weight, especially 0.1 to 5 parts by weight. Even if you use more than 5 parts by weight,
Even if used in a smaller amount than 0.1, the mechanical strength of the resin-bonded magnet is impaired.

Examples of the crosslinking agent, reaction initiator and reaction accelerator include styrene and its derivatives, diallyl phthalate, triallyl isocyanurate, various organic peroxides, tertiary amine acids, imidazoles, organic metal salts, and chlorides. And the like. These crosslinking agents, reaction initiators, and reaction accelerators may be used alone or in combination of two or more.

H. Resin-bonded magnet composition The resin-bonded magnet composition of the present invention is obtained by mixing the above-described magnetic alloy powder and a binder, followed by mixing powder such as silicon dioxide. In this case, it is preferable to mix optional components such as various surface treating agents and curing accelerators together with a binder, and finally mix powder such as silicon dioxide. As a result, the powder of silicon dioxide or the like is sprinkled on the surface of the binder covering 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 Nauta mixer,
The mixing can be performed using a mixer such as a Henschel mixer, a super mixer, a high-speed mixer, or the like, and the composition for a resin-bonded magnet can be prepared by using, for example, either a wet method or a dry method. In the wet method, an organic component such as a binder is dissolved in an appropriate organic solvent such as methyl ethyl ketone, mixed with a magnetic powder, and dried to remove the organic solvent.
This is a method of obtaining a composition by mixing powder such as silicon dioxide after removal . The dry method is a method in which components other than powder such as silicon dioxide are mixed at once using the above-described mixer or the like, and then the composition is adjusted by mixing powder such as silicon dioxide.

The resin-bonded magnet composition thus obtained uses a specific combination of an epoxy resin base material and a curing agent having a specific kinematic viscosity and a binder such as silicon dioxide powder on the surface of the binder. As a result, a powdery composition having no tackiness and extremely high fluidity is obtained.

I. The resin-bonded magnet composition for the resin-bonded magnet is press-molded using various compression molding devices, and then heat-treated to cure the binder, and then magnetized in a magnetic field if necessary, The desired resin-bonded magnet can be obtained. Press molding is usually performed under a pressure of 4 to 8 t / cm ² , and heat treatment varies depending on the type of binder used, a crosslinking agent, a curing accelerator, and a polymerization initiator. , For 1 to 4 hours. Magnetization in a magnetic field can be performed simultaneously with press molding, for example. The resin-bonded magnet thus obtained has a high density and high magnetic properties, and also has excellent mechanical properties such as strength.

[0027]

EXAMPLES A resin-bonded magnet composition of the present invention and a magnet using the same were produced and evaluated. In the following examples, the following materials were used.

I Magnetic Powder Magnetic Powder 1: Nd—Fe—B based magnet powder (trade name: MQP
-B, USA General Motors Corporation) anisotropy field: 70.4KOe magnetic powder 2: Sm-Co ₅ based magnetic powder (trade name: RCo ₅
Alloy, manufactured by Sumitomo Metal Mining Co., Ltd.) Anisotropic magnetic field: 246 kOe, average particle size 10 μm

II Epoxy resin base agent i) Bisphenol A type epoxy resin (trade name: Araldite GY260, manufactured by Nippon Ciba Geigy Co., Ltd.) ii) Novolac type epoxy resin (trade name: Araldite ECN1273, manufactured by Nippon Ciba Geigy Co., Ltd.)

III Silicon dioxide powder Trade name: Nip Seal SS-50 manufactured by Nippon Silica Industry Co., Ltd. Content of particles of 20 μm or less: 100% by weight Average particle diameter: 1-2 μm, maximum particle diameter: 10 μm

IV Urea Group Compound Powder a) N-Butyl-N'-stearyl urea (trade name:
B) Diphenylmethane bislauryl urea (trade name: Hakclean SB, manufactured by Nippon Kasei Co., Ltd.)
Huclean LM, manufactured by Nippon Kasei Co., Ltd.)

V Amide group compound powder a) Stearic acid amide (trade name: Amide AP)
-1, manufactured by Nippon Kasei Co., Ltd.) b) Ethylene bisstearic acid amide (trade name:
Slipax E, manufactured by Nippon Kasei Co., Ltd.)

IV curing agent a) Trade name: HT-972, manufactured by Nippon Ciba Geigy Co., Ltd. a) Dicyandiamide

Examples 1 to 24, Comparative Examples 1 to 11
According to the formulation shown in Tables 1 to 8, each epoxy resin base and curing agent were diluted 10-fold with methyl ethyl ketone,
This solution was added to the magnetic powder and mixed and stirred. Then
At 30 ° C., methyl ethyl ketone was completely volatilized under a reduced pressure of 10 ⁻¹ Torr, and powder such as silicon dioxide was further added according to the formulation shown in Tables 1 to 8, and mixed and stirred again to obtain a desired resin-bonded magnet. A composition for use was obtained.

In each of the compositions of the examples, the kinematic viscosity of the mixture of the epoxy resin base material and the curing agent used in a 70% by weight butyl carbitol solution by the Gardner method was measured at 25 ° C., and the measured value was 1 × 10 ^{−. 3} m ² /
Tables 1 to 8 show の も の or less as ○ and × as higher than 1 × 10 ⁻³ m ² / s. In addition, the composition obtained in each Example and Comparative Examples 1, 2, 3, 6, 9 was:
Although the composition was rich in fluidity, the compositions of Comparative Examples 4, 5, 7, 8, 10, and 11 exhibited tackiness that easily aggregated.

The powder fluidity of each composition was measured, and the results are shown in Tables 1 to 8. For the measurement of powder fluidity, the composition was placed in a mold (outside diameter 20 mm, inside diameter 18 mm, depth 35 mm)
After grinding and grinding, the amount of powder in the mold was evaluated, and the amount was 3 g or more, ○, 2 g or more and less than 3 g, Δ, and less than 2 g, x.

Each of the compositions obtained above was supplied into a press die, and press-molded at a molding surface pressure of 5.7 t / cm ² to obtain a plate-like 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-like sample was placed in the atmosphere at 180 ° C. × 1
Heat treatment was performed for a time, and the binder in the sample was cured to obtain a resin-bonded magnet. The magnetic properties of the obtained resin-bonded magnet were measured at room temperature using a thiophy-type self-recording magnetometer, and the measurement results of the maximum magnetic energy product ((BH) max) are shown in Tables 1 to 8. The magnetic characteristics of the resin-bonded magnet require that the maximum magnetic energy product be 11 MGOe or more.

Similarly, each of the compositions obtained above was supplied into a press mold, 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 was used. 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 at 180 ° C. for 2 hours in the air to cure the binder in the sample, thereby obtaining a resin-bonded magnet. The ring breaking strength of the obtained resin-bonded magnet was pressed under a condition of a head speed of 1 mm / min and at room temperature using an autograph manufactured by Shimadzu Corporation, and the maximum breaking strength was measured. The results are shown in Tables 1 to 3. The maximum ring breaking strength of the resin-bonded magnet needs to be 3.5 kgf or more. In addition,
In the above table, numerical values in the formulation are parts by weight.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

[Table 5]

[0044]

[Table 6]

[0045]

[Table 7]

[0046]

[Table 8]

From the above results, the resin-bonded magnet composition of the present invention is excellent in powder flowability, and the resin-bonded magnet using this resin-bonded magnet composition has magnetic properties and breaking strength. It turns out that both are excellent.

[0048]

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

Claims (4)

(57) [Claims] A magnetic alloy powder and at least bispheno
A type epoxy resin and novolak type epoxy resin
Epoxy resin bases and aromatic amine epoxy resin hardeners
Containing a silicon dioxide and urea group
Saturated aliphatic hydrocarbon, alicyclic hydrocarbon, aromatic carbon
Consists of one or more of hydrogen
Saturated aliphatic hydrocarbon containing urea group compound and amide group
Any one of hydrogen, alicyclic hydrocarbon, and aromatic hydrocarbon
Or from an amide group compound composed of two or more
Resin containing one kind of lubricant powder selected from the group consisting of
In the composition for a coupled magnet, the binder is 70% by weight.
% Butyl carbitol solution by the Gardner method
A kinematic viscosity (25 ° C.) of 1 × 10 ⁻³ m ² / s or less;
The lubricant powder is a binder formed on the surface of the magnetic alloy powder.
It exists in a state where it is scattered on the surface of the film.
A composition for a resin-bonded magnet as a feature . 2. The amount of the binder to be added is as follows.
0.5 to 5 parts by weight per 100 parts by weight.
The addition amount is 0.01 to 5 per 100 parts by weight of the magnetic alloy powder.
The resin according to claim 1, wherein the resin is a weight part.
A composition for a coupled magnet. 3. A magnetic alloy powder, after mixing the binder, claims, characterized in that mixing the powder lubricant
3. The method for producing the resin-bonded magnet composition according to 1 or 2 . 4. A resin-bonded magnet obtained by pressure-forming and heat-curing the resin-bonded magnet composition according to claim 1 .