JPH07135104A - Manufacture of polymer-rare earth composite magnet - Google Patents

Abstract

PURPOSE:To provide a method of producing a polymer-rare earth composite magnet that has improved magnetic characteristics and improved mechanical strength. CONSTITUTION:A material composed of magnetic particles coated with vinyltrimethoxysilane is mixed with a material composed of magnetic particles coated with isopropoxytitanium tris(dioctyl phosphate). This mixture is mixed with binder and is used to form polymer-rare earth composite magnets.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a composite magnet having excellent magnetic properties and mechanical properties, and more specifically, when mixing a magnetic powder and a binder, the magnetic powder is previously coated with isopropoxytitanium tris dioctyl phosphate. The present invention relates to a method for producing a rare earth composite magnet, characterized in that the treated magnetic powder and the magnetic powder coated with vinyltrimethoxysilane are mixed.

[0002]

2. Description of the Related Art It is well known in JIS C2502 permanent magnet material and the like that a composite magnet is manufactured by mixing magnetic powder and a binder and then by extrusion molding, compression molding or injection molding. However, with respect to the magnetic properties, the non-magnetic binder and the additives are mixed, so that the volume is reduced, which is a disadvantage. In order to improve this drawback, it is necessary to increase the filling amount of the magnetic powder and to increase the degree of orientation of the magnetic powder as much as possible.

[0003]

When a mixture of magnetic powder and binder is produced by compression molding, the magnetic properties
As a method of increasing the mechanical strength, a method of improving the density and the mechanical strength by a method such as increasing the molding pressure and adjusting the powder particle size has been proposed, and the improvement of the manufacturing method is progressing, but it is not yet sufficient. I can not say. As one of methods for improving such a problem, a method of coating magnetic powder with various coupling agents has been proposed.

This method has the effect of changing the surface of the magnetic powder from hydrophilic to lipophilic and improving the compatibility with the binder, and therefore it is said that the packing ratio, orientation and mechanical strength can be improved. . However, even when these methods are adopted, the mechanical strength decreases as the magnetic properties are increased, and the magnetic properties decrease as the mechanical strength is increased, and both have not been increased. In particular, in recent years, it is expected to be applied to small motors, OA equipment, and the like, and composite magnets are increasingly required to have a thin shape, and it is an important issue to improve mechanical strength without impairing magnetic characteristics. ing.

That is, an object of the present invention is to provide a method for producing a polymer composite type rare earth magnet capable of improving magnetic properties and mechanical strength.

[0006]

The present invention was obtained as a result of intensive research conducted by the present inventor to find out a manufacturing method for enhancing magnetic properties and mechanical strength. According to the present invention, a polymer composite is prepared. -Type rare earth magnet, characterized in that a mixed powder of isopropoxytitanium trisdioctylphosphate-coated magnetic powder and vinyltrimethoxysilane-coated magnetic powder is mixed with a binder and molded. Can be obtained.

[0007]

In the case of the present invention, the magnetic powder obtained by previously coating the magnetic powder with isopropoxytitanium trisdioctyl phosphate and the magnetic powder obtained by similarly previously coating the magnetic powder with vinyltrimethoxysilane are mixed, and the mixed powder is obtained. The binder and the binder are mixed so that the magnetic properties and the mechanical strength can be enhanced by the treatment effects of both, and both of them can be coated more than at the same time when both coating treatment agents are added at the same time. The processing effect of
The magnetic properties and mechanical strength are significantly improved.

[0008]

EXAMPLES The surface coating treatment agents used in the present invention are isopropoxytitanium tris dioctyl phosphate and vinyltrimethoxysilane represented by the following structural formulas.

[0009]

[Chemical 1] (Isopropoxy titanium tris dioctyl phosphate)

[Chemical 2] (Vinyltrimethoxysilane) The amount of the coating treatment agent used is 0.1 to 0.5% by weight of vinyltrimethoxysilane based on the magnetic powder, and isopropoxytitanium trisdioctylphosphate is the most suitable condition for the purpose of the present invention. 0.1 to 0.3% by weight based on the magnetic powder,
It is not limited to this amount. In addition, the mixing ratio of vinyltrimethoxysilane-coated magnetic powder; isopropoxytitanium tris-dioctylphosphate-coated magnetic powder is such that the magnetic properties and mechanical properties of isopropoxytitanium-trisdioctylphosphate-coated magnetic powder are too large or too small. This leads to a decrease in strength, so that the weight ratio is 1:
It is 3 to 1:10, more preferably 1: 7 to 1: 9. The treatment method is a generally called dry method, that is, a method of dissolving each coating treatment agent directly or in a small amount of a solvent and dropping or spraying magnetic powder while stirring, and a wet method, that is, a large amount of solvent. Any method of dissolving each coating treatment agent, stirring and mixing with the magnetic powder, and then removing the solvent by drying may be used. The present invention is not limited to this processing method.

The magnetic powder coated according to the present invention is then mixed with a binder and compression-molded to obtain a composite magnet body. The magnetic material composition obtained by such a method is not limited to compression molding and may be subjected to extrusion molding or injection molding.

As the magnetic powder, R ₂ T ₁₄ B (here, R
Is at least one of rare earth elements including yttrium, T is a transition element, and B is boron. ) Type alloy powder,
Rare earth cobalt magnet powder and the like are suitable, but not limited to these.

Regarding R ₂ T ₁₄ B, Nd ₂ Fe ₁₄
B is mentioned, but it is not limited thereto. Rare earth cobalt magnets are also known as SmCo ₅ or Sm ₂ Co, which are well known in JIS C2502 permanent magnet materials.
₁₇ etc. are mentioned, but it is not limited to these.

The embodiments of the present invention will be specifically described below.

[Example 1] 0.2 wt% of vinyltrimethoxysilane was added to 2-17 samarium-cobalt powder (average particle size: 30 µm) with respect to this magnetic powder, and after sufficiently mixing, at 120 ° C for 30 minutes. Processed. Similarly, 2
-17 series samarium cobalt powder (average particle size 30μm)
Then, 0.2 wt% of isopropoxy titanium tris dioctyl phosphate was added to this magnetic powder, and after sufficiently mixing, a treatment was carried out at 120 ° C. for 30 minutes. The magnetic powder coated with vinyltrimethoxysilane and the magnetic powder coated with isopropoxytitanium tris dioctyl phosphate were sufficiently mixed in a weight ratio of 1: 1 to 1:15.

Next, 3.0 w of a one-pack type epoxy resin as a binder is added to the mixed magnetic powder.
After adding t% and thoroughly mixing, the obtained mixture was molded with a compression molding machine at a molding pressure of 6 ton / cm ² and an applied magnetic field of 15 k.
Molded under the condition of Oe (1194 kA / m) 9 × 10
A molded product of × 10 was obtained. The molded body was cured at 150 ° C. for 1 hour. Figure 1 shows the evaluation results of the obtained molded products.
It was shown to.

Comparative Example 1 A test piece was obtained in the same manner as in Example 1 except that the surface coating treatment in Example 1 was not performed. The result is shown in FIG.

[Comparative Example 2] Vinyltrimethoxysilane and isopropoxytitanium trisdioctylphosphate were added to the magnetic powder at the same time so that the same addition ratio and total amount as in Example 1 were obtained, and the coating treatment was performed. A test piece was obtained in the same manner as in Example 1. The result is shown in FIG.

Example 2 Vinyltrimethoxysilane was added to Nd ₂ Fe ₁₄ B powder (average particle size 30 μm) in an amount of 0.3 wt% with respect to the magnetic powder, and the mixture was thoroughly mixed.
Treatment was carried out at 0 ° C. for 30 minutes. Similarly, Nd ₂ Fe ₁₄ B
Isopropoxy titanium tris dioctyl phosphate was added to the powder (average particle size 30 μm) in an amount of 0.
After 3 wt% was added and mixed well, a treatment was performed at 120 ° C. for 30 minutes. The magnetic powder coated with vinyltrimethoxysilane and the magnetic powder coated with isopropoxytitanium tris dioctyl phosphate were sufficiently mixed in a weight ratio of 1: 1 to 1:15.

Next, 3.0 w of a one-pack type epoxy resin as a binder is added to the mixed magnetic powder.
After adding t% and thoroughly mixing, the obtained mixture was molded by a compression molding machine under the condition of a molding pressure of 6 ton / cm ² to obtain a 9 × 10 × 10 molded body. This molded body is
Curing treatment was performed at 1 ° C. for 1 hour. The evaluation result of the obtained molded product is shown in FIG.

[Comparative Example 3] A test piece was obtained in the same manner as in Example 2 except that the surface treatment performed in Example 1 was not performed. The result is shown in FIG.

[Comparative Example 4] Vinyltrimethoxysilane and isopropoxytitanium trisdioctylphosphate were added to the magnetic powder at the same time so that the same addition ratio and total amount as in Example 2 were obtained, and the coating treatment was carried out. A test piece was obtained in the same manner as in Example 2. The result is shown in FIG.

From FIGS. 1 and 2, the magnetic properties and mechanical strength are improved as compared with untreated and simultaneous addition of both. Further, regarding the mixing ratio of the treated powder, it is found that vinyltrimethoxysilane and isopropoxytitanium trisdioctylphosphate are preferably 1: 7 to 9.

[0023]

As described above, according to the present invention, a very effective coating treatment method was found, and it was possible to obtain the effect of improving the magnetic characteristics and the mechanical strength. In the future, the industrial value of the present invention will be extremely great because the demand for composite magnets will be further expanded mainly in office automation equipment, and at the same time the size, thickness and weight will be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a mixing ratio of magnetic powder according to Example 1 of the present invention and mechanical strength and magnetic properties of a molded body (TP).

FIG. 2 is a diagram showing the relationship between the mixing ratio of magnetic powder and the mechanical strength and magnetic properties of a molded body (TP) according to Example 2 of the present invention.

Claims (3)

[Claims] 1. A method for producing a polymer composite type rare earth magnet, wherein a mixed powder of isopropoxy titanium tris dioctyl phosphate coated magnetic powder and vinyl trimethoxysilane coated magnetic powder is mixed with a binder and molded. And a method for producing a polymer composite rare earth magnet. 2. An R ₂ T ₁₄ B (wherein R is at least one of rare earth elements including yttrium, T is a transition element and B is boron) alloy powder as the magnetic powder,
2. A method for producing a polymer composite type rare earth magnet according to claim 1, wherein at least one kind of the rare earth cobalt magnet powder is used. 3. The mixing ratio of the vinyltrimethoxysilane-coated magnetic powder and the isopropoxytitanium trisdioctylphosphate-coated magnetic powder is in the range of 1: 3 to 1:10 by weight. Alternatively, the method for producing the polymer composite rare earth magnet according to claim 2.