JPH0469904A - Manufacture of rare earth bond magnet - Google Patents

Abstract

PURPOSE:To realize kneading and grinding almost under atmospheric condition and simplify facilities by kneading magnetic powder forming epoxy resin film and rust-proof film and a binder under the specified temperature condition and then grinding the kneaded material under the flow of inactive gas. CONSTITUTION:A film is formed by kneading epoxy main agent and rust-proof agent to rare earth, transition metal system magnetic powder. For the formation of a film, oxygen is replaced with an inactive gas and these materials are mixed in a mixing apparatus. Magnetic powder having formed film is kneaded with a binder resin having flexibility by a pressure type kneader. In the kneading process, the pressure type kneader is being cooled and kneading is carried out under the temperature condition of 95 deg.C or less, desirably in the temperature range from 50 to 60 deg.C Risk of firing in thus process can be prevented by this temperature setting.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing rare earth bonded magnets used in various devices such as rotating electric machines.

(Prior Art) Various relatively inexpensive yet powerful permanent magnets have been developed. For example, JP-A-59-211549
The publication proposes a bonded magnet in which rare earth-iron-boron magnetic powder is solidified with an adhesive, and JP-A-61-174364 proposes a bonded magnet in which rare earth metal-transition metal-boron magnetic powder is solidified with an adhesive. Plastic magnets mixed with a binder have been proposed.

Such rare earth bonded magnets are made by dispersing magnetic powder containing rare earth elements and transition metals in a binder resin by kneading, and the manufacturing method thereof is disclosed in, for example, Japanese Patent Application Laid-Open No. 1983-1989.
It is described in Publication No. 164313. A mixing roll is used in the kneading step of the manufacturing method disclosed in the above publication, and the rare earth magnetic powder and the silane coupling agent are mixed into the binder resin little by little while kneading is carried out. The obtained kneaded material is crushed and then rolled.

(Problems to be Solved by the Invention) When kneading magnetic powder containing rare earth elements and transition metals, or when pulverizing the kneaded product, there is a risk of ignition, and production may become impossible due to ignition. There is also a risk of falling into. For this reason, when magnetic powder containing rare earth elements and transition metals is kneaded or pulverized by conventional methods, a predetermined atmosphere is created to avoid the risk of ignition.

However, the equipment for forming the atmosphere must be very large-scale, requiring a large investment in equipment.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for producing a bonded rare earth magnet, which enables kneading and pulverization of magnetic powder containing rare earth elements and transition metals almost in the atmosphere, and which enables simplified equipment. With the goal.

(Means and operations for solving the problem) In order to achieve the above object, the method for manufacturing a rare earth bonded magnet described in claim 1 includes dispersing magnetic powder containing a rare earth and a transition metal in a binder resin. In the manufacturing method of rare earth bonded magnet.

At least (a) a magnetic powder containing a rare earth element and a transition metal, an epoxy resin, and a rust preventive agent are placed in a mixing device such as a ball mill and mixed to form an epoxy resin film and a rust preventive coating on the magnetic powder. (b) kneading the mixture obtained in the mixing step and the binder resin at a temperature of 95° C. or lower, and dispersing the magnetic powder containing the rare earth and transition metal in the binder resin; The method includes a kneading step, and (c) a pulverizing step of pulverizing the kneaded material obtained by the above-mentioned kneading step under a flow of inert gas.

Further, the method for manufacturing a bonded rare earth magnet according to claim 2 is the method for manufacturing a bonded sheet rare earth magnet according to claim 1, wherein the magnetic powder containing rare earth and transition metal contains boron. There is.

In a means having such a structure, an epoxy resin film and a rust-preventive coating are first formed on magnetic powder containing a rare earth element and a transition metal, and then the steps of kneading and pulverization are performed thereon. For this reason, during the kneading and pulverizing steps, the flow of oxygen into the material is blocked.

Furthermore, in addition to the above-mentioned oxygen blocking effect, the temperature in the kneading step is regulated to 95° C. or lower, which is below the ignition point, and in the pulverizing step, pulverization is carried out while being cooled under a flow of inert gas. For this reason, kneading and pulverization can be carried out with almost no risk of ignition.

The method for manufacturing a rare earth bonded magnet according to the present invention includes steps as shown in FIG.

First, a rare earth-transition metal magnetic powder is obtained by an ultra-quenching method.6 An example of an ultra-quenching method is a jet casting method.

In the jet casting method, an ingot-shaped rare earth-transition metal magnetic alloy is placed in a saucer, and the alloy is melted by high frequency or the like in an inert environment. The molten magnetic alloy is poured into a trough with a nozzle and dropped onto a rotating wheel through the nozzle. The rotating wheel is cooled by water, which provides rapid cooling. The rapidly cooled magnetic alloy solidifies into ribbon-shaped magnetic powder, falls downward, and is collected in a container.

Here, as the rare earth constituting the rare earth-transition metal magnetic powder, one or more kinds of lanthanoids are used, and as the transition metal, Fe and Co are used.

One or more types of Ni are used. This rare earth-transition metal magnetic powder can contain boron to form a rare earth-transition metal-boron magnetic powder. Specifically, Nd-Fe-B, Nd-Fe-Co-B, C
e-La-Fe-Co-B, Sm-Go, Sm-G
o-Fe, Ss-Go-Mn, etc. are used.

Next, an epoxy base agent and a rust preventive agent are mixed with the rare earth-transition metal magnetic powder to form a film (film forming step 8).

In forming the film of the epoxy base agent and the rust preventive agent, oxygen is replaced with an inert gas and the process is carried out using a mixing device for about 2 hours. As the mixing device, a ball mill, a V-type blender, a double cone-type blender, etc. are used.

The above-mentioned epoxy base agents include bisphenol, phenoxy, novolac, and polyphenol.

One or more types of polyhydroxybenzene or derivatives thereof are used, and as a rust preventive agent, a mixture of sorbitan monooleate and mineral oil or synthetic oil is used. Further, as the above-mentioned inert gas, argon gas (Ar), nitrogen gas (N2), carbon dioxide gas (CO
□) etc. are used, and the oxygen concentration after gas replacement is 3% ~
It is set to 0.08%.

The magnetic powder on which the epoxy resin film and rust preventive film have been formed is taken out and weighed, and then kneaded with a flexible binder resin for several minutes using a pressure kneader or the like (kneading step). At this time, a curing agent and a curing accelerator for the epoxy resin are added. The reason why the curing agent and curing accelerator are added at this stage is to avoid the magnetic powder from being hardened immediately after the magnetic powder mixture is taken out. Through such a kneading process, the rare earth-transition metal magnetic powder is almost uniformly dispersed in the flexible binder resin.

At this time, the flexible binder resin includes natural rubber (Nl), imprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), butyl rubber (IIR), and ethylene-propylene rubber (EP).
R), ethylene-acetate rubber (EVA), nitrile rubber (
NBR), acrylic rubber (AR), urethane rubber (UR)
) etc. may be used alone or in combination of two or more.

That is, the binder resin in this example is composed of a so-called ternary rubber, and contains a non-polar rubber component (for example, IIR
) and a highly polar rubber component (for example NBR),
Good mixing is achieved through the halogen-containing rubber component (eg CR).

Non-polar rubber components have difficulty in oil resistance and weather resistance, and highly polar rubber components are extremely hard and require the addition of extender oil or plasticizer. Therefore, if both rubber components are mixed via a halogen-containing rubber component, the rubber components that compensate for the drawbacks of each rubber component can be easily mixed together, improving oil resistance and weather resistance. be.

As the above-mentioned halogen-containing rubber component, one or more chlorine-containing rubber components such as chloroprene rubber (CR), Hypalon (C8M), and chlorinated polyethylene are used. In this case, the halogen-containing rubber component is 15% by weight based on the total weight of the binder resin.
It is preferable to set the following. If the rubber component containing halogen exceeds 15% by weight of the total weight of the binder resin, chlorine gas (C1□) or hydrochloric acid gas (
This is because, for example, in the case of a motor, this causes commutator corrosion, magnet rust, and core rust.

Examples of the curing agent include polyamines such as aliphatic polyamines and aromatic polyamines, acid anhydrides such as phthalic anhydride, polyamide resins, polysulfite resins, amine complexes such as boron trifluoride, and synthetic resins such as phenolic resins. Alternatively, one or more of these derivatives may be used. As curing accelerators, amines such as trisdimethylaminomethylphenol, 1-inbutyl-2
- Imidazole such as methylimidazole or one or more derivatives thereof are used.

In this kneading step, the pressure kneader is cooled, and kneading is carried out at a temperature of 95°C or lower, preferably 50 to 60°C. This temperature setting avoids the risk of ignition during the kneading process. That is, if kneading is carried out at a temperature exceeding 95°C, there is a risk of heat generation due to heat generation, and if the temperature is below 40°C, plasticization of the rubber will not proceed and sufficient kneading will not be carried out.

The magnet material obtained from the above kneading process (Y, Z) is taken out using a pressurizing method, and is then kneaded to a predetermined thickness of ~1.
6. Crushed (pulverized cloves). , the process of crushing the grains is as follows: argo/gas (8r), nitrogen gas (N, ), carbon dioxide gas (CO
2) Flow of inert gas such as 1: 5 temperature conditions +'1 is 95℃ or higher and 1. Set. A rotary blade or the like is used for the crushing 1c.In other words, in this crushing process, air cooling with inert gas 1, -J, is used, and the crushing process in prison is extremely difficult.
-The degree is now possible-) "C is here.

Step 4 of the pulverization step 1: J: The resulting pulverized product is rolled with a roller or the like in 1.1 to obtain a sheet-shaped bonded magnet (sheet formation 1- degree).

Thereafter, a predetermined heat treatment is performed and an appropriate = is cut. At this time, the magnetic powder [:' has been subjected to a protective treatment, so it has sufficient auxiliary ability even when cutting a sheet bond magnet. 1 line each) There is no mandatory 1, like this') process 1. -Y), a sheet-like rare #8 type bond magnet having a maximum energy product of 9° OEMGO+≧] is obtained. Maximum energy...product 9, O [MGOel 1: Then,
There are too many magnetic particles in the inner mouse, and there are too many magnetic particles. −
Drops, no.

In addition, various types of 1c) 1 converter, etc. 11. 'Use 1. Optimal tj゛Most person Mogami-1~Energy kernel (, 0[MriOe
] is 10 and greater than or equal to 1 energy M t:i 3 , 0
If the value is less than [MGOe], it is not possible to obtain a reliable rotating electric machine for the price of 5 magnetic e1.

(Example) Hereinafter, embodiments of the present invention will be explained in detail.

Example 1 - As magnetic powder, λ4QP manufactured by General Motors Co., Ltd. was ground in advance using a wet ball mill, and the particle size was adjusted to 1. I used Tachino. Furthermore, the magnetic powder described in -1- is a magnetic powder having a particle size of 2++m or less when formed by the ultra-quenching method.

This was pulverized to a particle size of 78 μrri or less. As the rust preventive agent 2, Rheodol S Pol manufactured by Kao Corporation is used.
In addition, Ebiko [28, manufactured by Yuka Shigol Co., Ltd.] was used as the chloride and boxydecorate.

Then, the magnetic powder, rust preventive agent, and alumina balls were placed in a ball mill container, and the air in the container was replaced with N2, and then mixed for 1 hour to form a rust preventive film on the surface of the magnetic powder. Next, the above mixture and the rubber binder were kneaded with a curing agent and a curing accelerator in a pressurized machine for 7 minutes, and then ground in a grinder. It was rolled to obtain 1-1... each. The curing agent, J7, and curing accelerator were Yl-13 manufactured by Yuka Schiff 4 Co., Ltd.
02 and -x r (M x-1, 2) 1 mouth 9S'/
:, -8 The temperature during kneading and grinding is approximately 5
It was kept at 5°C.

-) The rubber binder was heated to about 170° C. to vulcanize the rubber binder, and then cut in a prescribed manner to obtain a flexible magnet.

In this example, 1. The following table number 7 shows 16 (pier
) ■ I I R-, -N B i < -CR in the two tables,
NBR(
Nitrile rubber) is 60. CR (chloropropylene non-rubber) or 1, which is set at 15, is used in each step of kneading and grinding in this example! -9, it was confirmed that the J-poxy resin film and anti-rust coating were pre-formed on the magnetic powder, so that the inflow of oxygen into the material was almost completely blocked. In the - stage, the temperature is regulated by cooling in addition to the oxygen blocking effect, and in the pulverization stage, the cooling due to the flow of inert gas is 9J, causing a temperature rise above the set temperature. That never happened. Therefore, there was almost no risk of ignition during the kneading and crushing steps.

The magnetic properties of the obtained magnet are as follows: Br=5, 5[
KCl, 1llc=9. 9 [kOeko,
bHc=4. 5 [kOel, (BH)
,,.

= 6, 2 [MGOel was.

In addition, the obtained magnet was placed in a 90% R11 # atmosphere at 60°C.
When left for 0 hours, no rust was observed on the surface.

Furthermore, when used as a driving magnet for a brushed DC motor, even after 200 hours of continuous rotation at 60°C, the brush material (A, g-Pd) and the commutator material (A, g-Cd)
) No corrosion occurred.

As for salmon magnetic powder for my husband, MM14 (Feo, 5cOo-L)? 9
B? An alloy having the following composition was made into an ultra-quenched ribbon using a single roll method, and the ribbon was pulverized using a wet ball mill to adjust the particle size. As a rust preventive agent, Rheodol 5P-0 manufactured by Kao Corporation is used.
A mixed solution of No. 10 and Amprol 456 manufactured by Tenneco Chemical Company, USA was used. Thereafter, a sheet-shaped flexible magnet was obtained in the same manner as in Example 1 described above.

In each step of kneading and grinding according to this example,
It was confirmed that oxygen inflow into the magnetic material was almost completely blocked by the epoxy resin film and anti-rust coating. Furthermore, cooling during the kneading and pulverizing steps was sufficiently performed, and there was almost no risk of ignition during the kneading and pulverizing steps.

The magnetic properties of the magnet obtained in Example 2 are B
r= 4, 6 [KCl, 1Hc= 7, 0 [k
Oel, bl+c=3.1 [kOel, (B11)
0. = 4, 0 [MGOe was.

Furthermore, the obtained magnet was placed in an atmosphere of 60°C and 90% RH for 8
When left for 0 hours, no rust was observed on the surface.

Furthermore, when used as a driving magnet for a brushed DC motor, no corrosion occurred in the brush material (Ag-Pd) and commutator material (Ag-Cd) even after 200 hours of continuous rotation at 60°C.

As described above, the sheet rare earth bonded magnet according to the present invention is
It was confirmed that it can be suitably installed and used in rotating electric machines, etc.

Note that if metal powder having high magnetic permeability such as iron powder or iron alloy is used instead of permanent magnet powder, a flexible high magnetic permeability material can be formed.

(Effects of the Invention) As described above, in the method for manufacturing a rare earth bonded magnet according to the present invention, an epoxy resin film and a rust prevention coating are formed in advance on magnetic powder containing a rare earth element and a transition metal, and then each step of kneading and pulverization is performed. In addition to preventing oxygen from entering the magnetic material, the material is cooled to a predetermined temperature below the ignition point during the kneading and crushing processes, thereby avoiding the risk of ignition during the kneading and crushing processes. The magnetic powder containing rare earth elements and transition metals can be kneaded and pulverized almost in the atmosphere.

Therefore, according to the present invention, a large amount of equipment is not required for kneading and crushing, and the entire equipment can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram showing the manufacturing process of a rare earth bonded magnet according to the present invention. Diagram/Main ingredient

Claims (1)

[Claims] 1. A method for producing a bonded rare earth magnet comprising magnetic powder containing a rare earth and a transition metal dispersed in a binder resin, the method comprising at least the following steps. (a) A magnetic powder containing rare earths and transition metals, an epoxy resin, and a rust preventive agent are placed in a mixing device and mixed;
A mixing step of forming an epoxy resin film and an anti-rust coating on the magnetic powder. (b) A kneading step in which the mixture obtained in the above mixing step and the binder resin are kneaded under a temperature condition of 95° C. or lower, and magnetic powder containing a rare earth element and a transition metal is dispersed in the binder resin. (c) A pulverizing step of pulverizing the kneaded material obtained in the above kneading step under a flow of inert gas. 2. The method for manufacturing a sheet-shaped rare earth bonded magnet according to claim 1, wherein the magnetic powder containing rare earth and transition metal contains boron.