JPS61170003A - Compound magnet and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve a magnetic characteristics, a mechanical intensity, a formability and a thermal resistance by adding a zircoaluminate system coupling agent. CONSTITUTION:This contains not only a ferromagnetic powder as a main component but also a zircoaluminate system coupling agent. The zircoaluminate system coupling agent is what two kinds of organic ligands are selectively bonded with a low molecular weight of zircoaluminate skelton, and an aluminium acylate part of this coupling agent is tightly bonded with a surface of the ferromagnetic powder, and a zirconium works as an effective and stable organic reaction group. Therefore, a compound magnet whose manufacturing manday and manufacturing cost are a little increased, and whose magnetic characteristics, mechanical intensity, formability and thermal resistance are improved is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a composite magnet mainly composed of ferromagnetic powder and a polymer compound, and a method for manufacturing the same.

Conventional technology Composite magnets, which are made by blending ferromagnetic powder with polymeric compounds such as rubber or plastic, are used in magnetic sensors, small motors,
Gasket, center ring for cathode ray tube, magnet 1
-Used for various purposes such as rolls. This is because although the magnetic properties of composite magnets are inferior to anisotropic sintered magnets,
Reasons include the fact that by applying integral molding techniques such as injection molding, the final product shape can be obtained with almost no finishing processing required, and that products with light weight and complex shapes can be easily obtained.

Furthermore, since composite magnets have a lower packing density of magnetic powder than sintered magnets, they are often manufactured through an anisotropic process in order to obtain magnetic properties equivalent to or better than those of isotropic sintered magnets. This anisotropy step includes injection molding a mixture of ferromagnetic powder and a polymer compound in a magnetic field.

When manufacturing composite magnets, in addition to ferromagnetic powder and rubber or plastic, silane coupling agents or titanate coupling agents are used to improve magnetic properties, mechanical properties, formability, and thermal stability. Typical organometallic compounds are added to -C. For example, Japanese Patent Publication No. 55-32206 discloses surface-treating ferrite powder with an organosilicon compound in order to increase the amount of ferrite powder packed. Further, JP-A-59-10202 discloses that a remarkable modifying effect can be obtained by using a specific plasticizer and an amino group-containing organometallic compound in combination. Further, JP-A-59-93741 discloses the use of titanate coupling agents.

Problems to be Solved by the Invention Which of the above-mentioned silane-based or titanate-based organometallic compounds to use depends on the properties required of the magnet. In general, silane-based organometallic compounds are used when high mechanical strength and heat resistance are required, while titanate-based compounds are used when high fluidity but not so high mechanical strength is required. Machine metal compounds are used.

However, titanate-based hm metal compounds are more advantageous than silane-based organometallic compounds in terms of price and are about 40% cheaper than silane-based organometallic compounds, but they have the problem that the molded product becomes brittle. In addition, silane-based organometallic compounds are less expensive than titanate-based compounds, and require a drying process at 100 to 150°C for 1 hour after surface modification treatment, which increases manufacturing man-hours and costs. be.

The purpose of the present invention is to solve the problems of the prior art described above,
It is an object of the present invention to provide a composite magnet that has improved magnetic properties, mechanical strength, formability, and heat resistance, with a small increase in manufacturing man-hours and manufacturing costs.

Another object of the present invention is to provide a manufacturing process that can stably produce a composite magnet that is inexpensive and has excellent magnetic properties, mechanical strength, formability, and heat resistance.

Means for Solving the Problems The composite magnet of the present invention is characterized in that it contains a zircoaluminate coupling agent along with ferromagnetic powder and resin as main components.

Further, in the method for manufacturing a composite magnet of the present invention, a mixture containing a ferromagnetic powder, a resin, and a zircoaluminate coupling agent is fluidized in the presence of a magnetic field.

It is characterized by being injected into a molding space of a predetermined shape, and then being cooled and solidified.

Structure of the Invention As a result of various studies on surface additives for composite magnets, the present inventors have found that magnetic properties, mechanical strength, formability, and heat resistance can be improved by adding a zircoaluminate coupling agent. found. Furthermore, the price of this coupling agent is approximately 20% of that of conventional silane coupling agents, making it extremely advantageous in terms of price.

In other words, the zircoaluminate coupling agent is obtained by selectively bonding two types of organic ligands to a low molecular weight zircoaluminate skeleton, and the aluminum acylate portion of the coupling agent is strongly It is thought that the above-mentioned effects are obtained by strongly bonding to the surface of the magnetic powder and by zirconium acting as an effective and stable organic reactive group.

The effect of adding a zircoaluminate coupling agent will be explained from the viewpoint of surface treatment mechanism as follows.

The zircoaluminate coupling agent has a side chain hydroxyl group bonded to the surface of the ferromagnetic powder, has a combination of hydrogen bonds and covalent bonds, and is irreversibly bonded to the surface of the ferromagnetic powder. Therefore, when a zircoaluminate coupling agent is added to a mixture mainly composed of ferromagnetic powder and resin, the interaction between the ferromagnetic powders is significantly reduced.
Produces uniform dispersion of ferromagnetic powder and reduced viscosity of the mixture,
The above-mentioned effects can be obtained. In order to obtain such an effect, the amount of brass added to the zircoaluminate coupling agent is 0.5 parts by weight or more per 100 parts by weight of ferromagnetic powder.
Therefore, less than 1 part by weight is sufficient.

Next, zircoaluminate coupling agents are broadly classified into alcohol-based and glycol-based based on the type of solvent, but alcohol-based coupling agents are superior in terms of price and ease of solvent removal, and are used in composite magnets. Alcohol is suitable for this.

In addition, zircoaluminate coupling agents, both alcohol and glycol, have different physical properties depending on the type of functional group (amino group, carboxyl group, fatty acid, methacryloxy group, methcaptan group, methacryloxy group/fatty acid, etc.). It may be selected depending on the resin used. For example, polyamide resins and polycarbonate resins preferably contain amino groups, acrylic resins preferably contain carboxyl groups, and polyethylene preferably contain fatty acid or methacryloxy groups.

The ferromagnetic powder that is one of the main components of the composite magnet of the present invention includes hard ferrite powder such as 3a-ferrite and 3r-ferrite, alnico magnet powder, Fe-C
At least one kind of known ferromagnetic powder such as r-GO alloy powder, rare earth cobalt magnet powder, rare earth/iron/boron magnet powder can be used. Other resins that are one of the main components include saturated polyester, polyphenylene oxide, polycarbonate, polyacetal, polyamide, fluororesin, polypropylene, polyethylene, methacrylic resin, ABS resin, As resin, polystyrene, polygonyl acetal, and ethylene. Polymer, vinyl chloride resin, vinylidene chloride resin, polyphenylene sulfide, polyether sulfone, polysulfone, polyether ether ketone, polyethylene terephthalate,
Thermoplastic resins such as polybutylene terephthalate, polyarylate, aromatic polyamide, polyurethane, and phenolic resins, urea resins, melamine resins, furan resins,
Thermosetting resins such as alkyd resins, unsaturated polyesters, diallyl phthalate resins, epoxy resins, and silicone resins, and chlorinated polyethylene, styrene/butadiene rubber, cis-polybutadiene, RI-O-lobrene rubber, butyl rubber, nitrile rubber, ethylene propylene rubber, Hypalon, Rubbers such as acrylic rubber, silicone rubber, fluororubber, and polysulfide rubber can be advantageously used. These can be used alone or in combination.

The blending amounts of the above-mentioned ferromagnetic powder and resin may be determined by considering the magnetic properties and moldability required of the magnet, but generally the weight ratio of ferromagnetic 6 grade powder:resin is 50 to 50. 95
: It is best to set it to 5G to 5. This is because if the blended amount of ferromagnetic powder is less than 50 parts by weight, magnetic properties equivalent to those of an isotropic sintered magnet cannot be obtained even if the anisotropic treatment described below is performed, and the blended amount is less than 95 parts by weight. This is because molding becomes extremely difficult if it exceeds this range.

Furthermore, in addition to the above, low molecular weight ethylene acrylate or ethylene triacrylate and calcium stearate, silicone oil, tricresyl phosphate, ethylene bis fatty acid amide, mellitic acid ester, polyethylene wax, ester wax, partially saponified ester wax, antioxidants, etc. A small amount (several parts by weight) of additives may be added.

According to the present invention, a composite magnet having anisotropy can be manufactured using the above raw materials in the following manner.

First, the surface of the ferromagnetic powder is treated with a zircoaluminate coupling agent. The surface treatment may be carried out, for example, by putting the ferromagnetic powder into a known mixer, spraying and adding a solution of a zircoaluminate coupling agent while stirring, stirring thoroughly, and drying. .

Next, this ferromagnetic 6 grade powder and resin are mixed with additives as required, and then heated and kneaded and pelletized to obtain a pellet-like compound.

This compound is injected into a molding space equipped with a magnetic circuit for orientation around the periphery, molded while applying a magnetic field and heated, and after being cooled and solidified, the molded body is taken out from the mold. In order to achieve sufficient anisotropy, it is preferable to perform molding in a magnetic field of 2000 Qe or higher. The molded body obtained in this way can be magnetized in the same direction as the anisotropy direction without the need for further processing to form an anisotropic composite magnet, but if necessary, the outer diameter can be processed to a predetermined size. It's okay.

In addition, when this composite magnet is used for a magnet roll or a rotor magnet for a motor, so-called insert molding may be performed in which the shaft is inserted into a mold in advance and then the crosstalk is injected.

EXAMPLES AND COMPARATIVE EXAMPLES The present invention will now be explained in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 3r ferrite powder with an average particle size of 1.30 μm (mole ratio 5
,50, Si02 0.18wt%, CaO00
After adding 15kQ (containing 32w℃%) to the Henschel mixer, add Zirco 7 luminate agent (product number AIAVEDON CHEMICAL!Ii) while stirring.
) 75.4 ka was diluted with the same volume of an aqueous ethanol solution (water:ethanol mixed at a volume ratio of 1:9) and added by spraying, and after the addition was completed, the mixture was further stirred for 10 minutes using a Henschel mixer. The powder was then dried at 80° C. for 30 minutes to obtain 3r ferrite powder whose surface was treated with zircoaluminate.

Next, 14.5klJ of magnetic powder and nylon 12 powder with 32 mesh under (P-3014U manufactured by Ube Industries) 2.
To 360! After mixing II with a Henschel mixer,
The mixture was kneaded at 230° C. using a twin-screw extruder to obtain pellets of about 3 mm. This is the patent application filed in 1983-2 by the present applicant.
2) Injection molded at an injection temperature of 80°C using an injection molding machine equipped with a magnetic circuit described in No. 4ri No. 0 (filed on November 21, 1980), with an outer diameter of 40φ, an inner diameter of 35φ, and a height of 9. .6
A 100-pole anisotropic ring magnet of a+m was obtained. After this was magnetized under predetermined conditions, the surface magnetic flux density (BO) was measured. Further, after demagnetizing this, the crosshead speed was set to 0.
A compression test was conducted under the conditions of 5ms+/sin to measure the crushing strength.

Examples 2 to 6 The amount of zircoaluminate coupling agent added was 1.0
A molded body was produced under the same conditions as in Example 1 except that the amount was 4.0 parts by weight (per 100 parts by weight of LA powder), and the BO and crushing strength were measured.

Comparative Example 1 A molded body was produced under the same conditions as in Example 1, except that 3r ferrite powder was used without being treated with a zircoaluminate coupling agent, and its BO and crushing strength were measured.

Comparative Example 2 The amount of zircoaluminate coupling agent added was 4.3
Example 1 except that the heavy ω part (per 100 parts by weight of magnetic powder) was used.
After manufacturing a compound under the same conditions as above, injection molding was performed, but the compound could not be sufficiently filled into the cavity and molding was impossible.

Comparative Example 3 A molded body was produced under the same conditions as in Example 1 except that a silane coupling agent (KBM-603 manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of the zircoaluminate coupling agent.
O and crushing strength were measured.

Comparative Example 4 A molded article was produced under the same conditions as Example 1, except that a titanate coupling agent (manufactured by Ajinomoto Co., Ltd., KR-388) was used instead of the zircoaluminate coupling agent, and isopropyl alcohol was used as the diluted solution. and BO
and the crushing strength was measured.

Example 7 3a ferrite powder with an average particle size of 1.05 μm (molar ratio 5
．． 34, Si02 0.13wt%, AQ. 20
30, os wt% addition) was treated with 0.7 parts by weight of a zircoaluminate coupling agent (product number A) by the method of Example 1. 29.2 kg of magnetic powder
and nylon 6 powder (manufactured by Ube Industries, Ltd. 1011-FB)
25,6ka and EEA powder (PES- manufactured by Nippon Unicar)
210> 2.09 and 9 were thoroughly mixed in a Henschel mixer, and then kneaded in a twin-screw extruder to produce pellets. Hereinafter, a molded body was manufactured under the same conditions as in Example 1, and B
O and crushing strength were measured.

Example 8 100 parts by weight of the 3r ferrite powder used in Example 1 was surface treated with 0.6 parts by weight of a zircoaluminate coupling agent in the same manner as in Example 1. Next, the magnetic powder 8
．． 37k (J and PPS powder (Philips Petroleum v1)
) 1.25kg EEA powder (MS made by Kerr in Japan)
-870) 0.38 hg. Thereafter, a molded body was produced in the same manner as in Example 1, and its BO1 crushing strength was measured.

Comparative Examples 5 and 6 Compounds were produced under the same conditions as in Examples 7 and 8, except that untreated magnetic powder was used, and molded bodies were produced using each compound under the same conditions, and the BO crushing was performed. The strength was measured.

(T-margin) Table 1 * Injection moldability...O: Good Δ: Can be molded The thermogravimetric loss of each of the produced Funbounds was measured using a thermobalance (Rigaku Denki 81118).
Shown in the table. The values in Table 1 are based on the heating rate of 10°C/1 in air.
Indicates the weight loss rate (used in the formula below) at 200°C for J0 11F! Lose (?1-) = (loss rate 1/first 11 [1)
As shown in Table 1 of X100, it can be seen that the addition of 2.0 parts by weight or less of a zircoaluminate coupling agent improves the BO1 crushing strength and formability.

Furthermore, even when the amount added is 2.0 to 3.0 parts by weight, the -UBo value is slightly lower than that of the untreated sample, but the crushing strength tends to be high. Further, from a comparison between Example 1 and Comparative Examples 3.4, it can be seen that the zircoaluminate coupling agent exhibits an effect equal to or greater than that of the silane coupling agent. Furthermore, it can be seen from the comparison of weight loss that there is a tendency for thermal stability to improve.

Next, as shown in Table 2, it can be seen that addition of a zircoaluminate coupling agent is effective even when two or more types of resins are used.

As described above, according to the present invention, by using a zircoaluminate coupling agent, a composite magnet with excellent magnetic properties, mechanical properties, formability, and thermal stability can be manufactured at low cost. .

Claims (1)

[Claims] 1. A composite magnet characterized by containing a ferromagnetic powder, a polymer compound, and a zircoaluminate coupling agent. 2. 50 to 95 parts by weight of ferromagnetic powder and 50 to 95 parts by weight of polymer compound
The composite magnet according to claim 1, comprising 5 parts by weight of a zircoaluminate coupling agent and 0.04 parts by weight or less per part by weight of ferromagnetic powder. 3. The composite magnet according to claim 2, which contains ferromagnetic powder surface-treated with 4 parts by weight or less of a zircoaluminate coupling agent per 100 parts by weight of ferromagnetic powder. 4. A mixture containing ferromagnetic powder, thermoplastic resin, and zircoaluminate coupling agent is fluidized, injected into a space of a predetermined shape in the presence of a magnetic field, and then cooled and
A method for manufacturing a composite magnet characterized by solidification. 5. 50 to 95 parts by weight of ferromagnetic powder and 50 to 95 parts by weight of thermoplastic resin
5. The method for producing a composite magnet according to claim 4, which uses a mixture of 5 parts by weight and 4 parts by weight or less of a zircoaluminate coupling agent.