JPH0265103A - Rare earth-iron resin binder and resin magnet using the same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rare earth-iron resin binder whose main component is a thermoplastic resin, and a resin magnet using the binder.

[Conventional technology]

Resin magnets manufactured by molding a mixture of rare earth element-iron magnetic powder such as rare earth element-iron-boron and thermoplastic resin as a binder have (1) high dimensional accuracy and can be formed into complex shapes; , (2) Good uniformity of quality and performance, (
It has advantages such as 3) improved mechanical strength and (4) ability to be molded into a body, and its applications are expected to expand.

Conventionally, when manufacturing this resin magnet, the surface of the rare earth-iron magnetic powder is treated with dyes, phosphorus compounds, organopolysiloxane, etc. in order to prevent oxidation of the magnetic powder and improve moldability. It has been known.

[Problem to be solved by the invention]

However, rare earth-iron resin magnets manufactured by such a method do not fully satisfy any of the magnetic properties, oxidation resistance, and mechanical strength.

The purpose of the present invention is to solve the above problems and provide a rare earth-iron resin magnet with improved magnetic properties, oxidation resistance, and mechanical strength as much as possible. The goal is to improve resin binders.

[Means to solve the problem]

To achieve the above object, the present invention is a rare earth-iron resin binder characterized by containing (a) a thermoplastic resin, fb) a higher fatty acid and/or a salt thereof, and an fcl lubricating oil.

In the rare earth-iron resin binder of the present invention, (b
) Higher fatty acids and/or salts thereof and (c1 lubricating oil) are each used in amounts of 0.
It is preferably 1 to 20 parts by weight, preferably 0.1 to 20 parts by weight.

Examples of the thermoplastic resin include nylon, polyethylene, polybutadiene, polyester, and polyphenylene sulfide. In addition, higher fatty acids added to this resin include capric acid, n-undecylenic acid, lauric acid, n-tricosanoic acid, myristic acid, n-pentadecylenic acid, palmitic acid, margaric acid, stearic acid, and n-nonadecylenic acid. , araxic acid, n-henicosanoic acid, behenic acid, n-tricosanoic acid, lignoceric acid, etc. Salts of higher fatty acids include Ca, Zn, Aβ, Li, 5rNa,
Examples include metal salts such as Mg and Sn. These give excellent fluidity to the resin binder by lowering the melt viscosity of the thermoplastic resin and improving the interfacial smoothness between the thermoplastic resin and the rare earth iron-based magnetic powder having a coupling agent coating. If the amount is less than 0.1 part by weight per 100 parts by weight of the thermoplastic resin, the above effect will not be sufficient and moldability will deteriorate. On the other hand, if the amount exceeds 20 parts by weight, the mechanical strength of the produced rare earth-iron resin magnet tends to decrease.

Furthermore, examples of the lubricating oil added to the thermoplastic resin include silicone oil, modified silicone oil, wax, paraffin, etc., and preferably silicone oil,
It is a modified silicone oil. These give excellent fluidity to the resin binder, excellent kneading and moldability to the resin binder mixture, and oxidation resistance to the rare earth-iron resin magnet, but the amount thereof is 0.000 parts per 100 parts by weight of the thermoplastic resin.
If the amount is less than 1 part by weight, the above effect will not be sufficient, while if the amount exceeds 20 parts by weight, the mechanical strength of the rare earth-iron resin magnet will tend to decrease.

Another aspect of the present invention is a resin magnet comprising the above resin binder and rare earth-iron magnetic powder having a coupling agent coating.

In the resin magnet of the present invention, the amount of the resin binder is preferably 4 to 15 parts by weight per 100 parts by weight of rare earth-iron magnetic powder.

The rare earth-iron magnetic powder to be used is not particularly limited, such as the R (rare earth element)-Fe-B system, but the known liquid quenching method (Japanese Patent Laid-Open Publication No. 1983-1983) involves ultra-quenching a molten metal, followed by heat treatment and pulverization. 210934. Japanese Patent Publication No. 59-64739, etc.)
The resin binder prepared by the method requires a resin binder with excellent fluidity, and the effect of using it is particularly large. and,
The average particle size of the rare earth-iron magnetic powder is 3 to 500μ.
m may be adopted as appropriate.

Such rare earth-iron magnetic powder is coated with a coupling agent, which is commonly used. This is done in order to impart oxidation resistance to the rare earth-iron magnetic powder and to increase the adhesion strength with the resin binder, thereby improving the mechanical strength of the resin magnet.

Coupling agents include (1) γ-aminopropyltrimethoxysilane, T-glycidoxy-propyltrimethoxysilane, N-β-(aminoethyl)T-amino-propyltrimethoxysilane, phenyltrimethoxysilane; Single substances and mixtures of silane coupling agents such as silane, methyldimethoxysilane, and methyljethoxysilane; (2) Isoprobilt IJ isostearoyl titanate, di(dioctyl pyrophosphate) ethylene titanate, diisostearoyl ethylene natanate, dicumyl felt; Single or mixtures of titanate coupling agents such as oxyacetate titanate, di(dioctyl pyrophosphate) oxyacetate titanate, di(dioctyl phosphate) ethylene titanate, and tetraoctyl di(ditridecyl phosphite) titanate can be used.

If the amount of the resin binder is less than 4 parts by weight per 100 parts by weight of the rare earth-iron magnetic powder, it will be difficult to mold it;
If it exceeds 5 parts by weight, magnetic properties tend to deteriorate.

[For production]

As explained above, the fluidity of the resin binder can be improved by coating the rare earth-iron magnetic powder used with a coupling agent and adding higher fatty acids and/or their salts and lubricants to the thermoplastic resin. The adhesion strength with the magnetic powder and the oxidation resistance of the magnetic powder can be improved. Among the above, improving the fluidity of the resin binder reduces the amount of resin binder used, improves the magnetic properties of the resin magnet, and also improves the kneading and molding properties of the resin binder mixture. Furthermore, the improvement in the adhesion strength with the magnetic powder improves the magnetic properties by making the coupling agent coating thinner, and also improves the mechanical strength of the resin magnet.

The resin binder of the present invention comprises (a) a thermoplastic resin, (b)
1 higher fatty acid and/or its salt and (c1 lubricating oil), respectively, are mixed in an unrestricted order.

The mixed solution is added and mixed in an appropriate amount to magnetic powder coated with a coupling agent by a known method, and the resulting composition is formed into a pellet or the like, and the mixture is placed in a magnetic field or in a non-magnetic field. After a molded product is obtained by injection molding, extrusion molding, or the like, this molded product is magnetized to obtain a rare earth-iron resin magnet with excellent magnetic properties, oxidation resistance, and mechanical strength.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on examples, as well as comparative examples and conventional examples.

Example 1 Nd, □, 5FeB□, 5B created by liquid quenching method
, 500 g of magnetic powder (average particle size 200 μm) was added with 0 gamma-aminotriethoxysilane as a silane coupling agent.
．． 5g dissolved in isopropyl alcohol 200n/!
After adding and stirring thoroughly, vacuum drying was carried out day and night. Add 3g of stearic acid to the resulting powder as a resin binder.
A mixture of 3 g of silicone oil and 38 g of nylon 12 was added and thoroughly mixed, and then kneaded at 230°C. At this time, the steady torque applied to the screw of the kneader was read.

Next, this kneaded material was crushed into pellets having an average size of 3 dragons. These pellets were produced using a barflow mold with a bar groove shape of 5 squares wide and 2 squares deep at 260°C and 1000 kg/
Injection molding was carried out under conditions of "cm", and the flow length was measured.

Furthermore, the pellets obtained above were incubated at 260°C, 1' OOO
It is injection molded under the condition of kg/cm2, and is made into a prismatic shape (width 12.7 cm).
A resin magnet in the shape of a disk (diameter: 20 mm, height: 13 mm) was obtained.

The bending strength, magnetic properties, and oxidation resistance of this resin magnet were measured. The oxidation resistance was determined by visually observing the presence or absence of rust on the surface of the sample after exposing it to an atmosphere of 80° C. and 90% relative humidity for 500 hours. Furthermore, a recycling test was conducted in which the sprue and runners generated when obtaining the resin magnet were collected and the process of injection molding using them was repeated.

The above results are shown in Table 1.

Examples 2 to 5, Comparative Examples 1 to 7 Tests were conducted in the same manner as in Example 1, except that the type and amount of the resin binder compound were changed as shown in Table 1. The results obtained are shown in Table 1.

Conventional Examples 1 to 6 No surface treatment of magnetic powder was performed (Conventional Examples 1 to 4), and surface treatment was performed using a dye and a phosphorus compound (Conventional Example 5)
．． 6) The test was conducted in the same manner as in Example 1 except that the mixture was kneaded under the conditions shown in Table 2. The results obtained are shown in Table 2.

〔Effect of the invention〕

From the above, the present invention provides a rare earth-iron resin magnet having excellent magnetic properties, oxidation resistance, and mechanical strength, and a resin binder mainly composed of a thermoplastic resin suitable for use in manufacturing the same. It turns out that it is provided.

Claims (4)

[Claims] 1. A rare earth-iron resin binder comprising (a) a thermoplastic resin, (b) a higher fatty acid and/or a salt thereof, and (c) a lubricating oil. 2. The blending ratio of (b) higher fatty acid and/or its salt and (c) lubricating oil is 0.1 to 20 parts by weight and 0.1 to 20 parts by weight, respectively, based on 100 parts by weight of (a) thermoplastic resin. The rare earth-iron resin binder according to claim 1. 3. A resin magnet comprising a rare earth-iron magnetic powder having a coupling agent coating and a resin binder containing (a) a thermoplastic resin, (b) a higher fatty acid and/or a salt thereof, and (c) a lubricating oil. 4. The blending ratio of the resin binder is rare earth-iron magnetic powder: 1
4. The resin magnet according to claim 3, wherein the amount is 4 to 15 parts by weight based on 0.00 parts by weight.