JPS62230008A - Resin magnet - Google Patents

Abstract

PURPOSE:To contrive stabilization of functions while retaining and ensuring a reliability such as of chemical resistance and irreversible demagnetizing factor by connecting a rare earth magnetic powder with an epoxy resin and dicyandiamide and/or a specific dielectric. CONSTITUTION:A rare earth magnetic powder is connected with an epoxy resin and dicyandiamide and/or a dielectric expressed by a chemical fomula I As a result, various defects during manufacturing steps can be removed, while maintaining a chemical resistance or the restraint of a irreversible demagnetizing factor of a resin magnet formed by connecting a rare earth cobalt magnetic powder with an epoxy resin composition. In the above formula, R1 and R2 are aliphatic residues.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to resin magnets used widely in the mechatronics field as members of pulse motors, servo motors, actuators, etc. This relates to resin magnets bonded together.

BACKGROUND OF THE INVENTION As a resin magnet exhibiting a high degree of magnetic performance, one in which rare magnetic powder is bonded with an evo resin composition of 2 to 6 weight percent is known. The epoxy resin composition is generally composed of an epoxy resin and a crosslinking agent that three-dimensionally crosslinks the epoxy resin. However, a small amount of the epoxy resin composition, 2 to 6% by weight, has a significant effect on the properties and functions of the resin magnet.

First of all, epoxy resin is a resin containing at least 2 or more oxiranes TI5 in one molecule as shown in the above general formula.
It is a general term for compounds that

However, Y in the above formula is a polyfunctional halohydrin, for example, a residue of a reaction product of epichlorohydrin and polyhydric phenol. Polyhydric phenols useful herein are resorcinol and bisphenols formed by condensation of phenol with aldehydes or ketones. Representative examples of these hisphenols include bisphenol Δ, which is 2,2'-bis(P-hydroxyphenyl), and 4,4'-dihydroxyhyphenyl.
4,4'-dihydro [1 Jacchi r, 4,4'-Schihi J: r-+ i-.

There are 1-xydiphenyl oxide, 2,2'-dihydrogen methane, and 2,2'-dihydroxydiphenyl oxide. j4 The most 117 epoxy resin can be expressed as 11 by the general formula in G.

C112-Ct(-CI-(2-(0-@-Rn-
<6) -0-0■( CII 2-CII-CH23-0-@-Rn -<9
> -0-/ゝ\Cl12-CII-C)-(2 (T71.-h In the formula, R is a divalent group selected from a saturated alkidine group having 1 to 8 atoms, an acid (≦, and a sulfone group) , y is O or an integer up to 25, and T1 is 0 or 1.

A compound ([I GE BA ) of epichlorohydrin and His7 enol A can be exemplified as a particularly representative example.

Next, as a crosslinking agent for the epoxy resin as described above, in particular, for a Zuroresin magnet composed of rare earth magnetic powder and an epoxy resin composition, examples of the crosslinking agent for the epoxy resin include JP-A-60-37106 and JP-A-60-37106. According to the description in No. 60-2073-02, it is an azole compound having an amino group,
It is disclosed that it is specific to imidazoles represented by the following general formula.

1F1. L, )-, formula middle summer <1. R2, R3 and R4 are individually selected from hydrogen, lower alkyl, phenyl and lower alkyl phenyl. For example, imidazole, 2-ethyl-4 medylimidazole, ■
-benzy-2-methylimidazole, 1-methylimidazole, and 2.2-dimethylimidazole.

The above-mentioned epoxy resin composition containing an epoxy resin (for example, DGEBA) and an imidazole as a crosslinking agent for the epoxy resin generally provides a cured product having excellent chemical resistance and heat resistance. Therefore, in other words, it is known that resin magnets composed of rare earth magnetic powder and epoxy resin compositions are particularly effective in terms of chemical resistance and suppression of irreversible demagnetization rate at high temperatures.

Problems to be Solved by the Invention However, since imidazoles are generally solids with a high melting point (above 20°C), it is difficult to mix them with epoxy resins, and the pot life of the liquid mixture is generally within 7 days at room temperature. belongs to. Mixed epoxy resins tend to gradually react with imidazoles to form dimers and trimers, thereby increasing their viscosity. The viscosity of such an epoxy resin composition is the same even when it is mixed with rare earth magnetic powder, so especially when manufacturing magnetically anisotropic resin magnets, the degree of magnetic field orientation decreases and, for example, the residual magnetic flux density Br increases. It decreases depending on the degree of

Eventually, it became impossible to mold the resin magnet itself.

On the other hand, in order to facilitate the magnetic field orientation of the rare earth magnetic powder at the stage of molding the resin magnet, the epoxy resin composition is usually at least in liquid form.

Therefore, it is inevitable that the sliding parts of the mold become wetted with the epoxy resin composition. The epoxy resin composition adhered to all surfaces of the mold also gradually thickens and eventually gels. This fact reflects the maintenance and maintenance of resin magnet manufacturing equipment.
This results in an increase in the difficulty of management or the work itself.

In addition, if emidazoles are lower fatty acids or phosphates,
Since it can be in the form of a liquid or a solid with a low melting point at room temperature, mixing with the epoxy resin becomes easy. The mixture also has the advantage of a long pot life, so it has less influence on magnetic anisotropy at the resin magnet manufacturing stage, stabilizes Br, and facilitates workability. In response to this, the epoxy resin that reacts with the acid in the salt becomes monofunctional, resulting in decreased chemical resistance and heat resistance.In particular, the stability of the salts in which the basicity of imidazoles is neutralized with acid is The more acidic the acid, the more stable the epoxy resin composition will be, but this will further reduce the chemical resistance and heat resistance of the epoxy resin composition.In other words, the properties of resin magnets using imidazoles will be lower. This eliminates the advantageous effects of heavy product resistance and suppression of irreversible demagnetization rate.

On the other hand, it is desirable that each particle of the rare earth magnetic powder be individual and not aggregated, at least at the stage of manufacturing a resin magnet. However, the rare earth magnetic powder is a substance that is very easily oxidized by moisture and heat. For this reason, surface treatment is usually performed using carbon functional silane or the like, but aggregation is unavoidable when forming a monomolecular or larger film. Furthermore, when the agglomerated rare earth magnetic powder is mechanically separated, destruction of the membrane is unavoidable.

Therefore, rare earth magnetic powders are usually carefully stored in a deoxidized and dehumidified atmosphere.

The present invention was accomplished with the object of eliminating various drawbacks in the manufacturing stage while maintaining the chemical resistance and suppression of irreversible demagnetization rate of a resin magnet in which the above-mentioned rare earth cobalt magnetic powder is bonded with an epoxy resin composition. be.

Means for Solving the Problems The present invention is a resin magnet in which rare earth magnetic powder is bonded to an epoxy resin and dicyandiamide and/or its derivatives. Furthermore, the epoxy resin has an oil absorption function containing a polyglycol type epoxy resin and/or carbon functional silane, and Sm(
Co, Cu.

Fe, M)n (where M is one or more elements belonging to Group II, Group V, Group VI, or Group VII of the periodic table, n is generally an integer from 5 to 9) or R+-x () ;'6+-
y, By)x (where R is Nd or/and Pr.

X is 0.5 to 0.9. y is 0.05 to 0.10).

Function: The epoxy resin referred to in the present invention includes a condensate of epichlorohydrin and bisphenols represented by DGEBA, as well as novolak type, polyphenol type, polyhydroxyhensen type, aromatic carboxylic acid type, alicyclic type, etc. Can be used. And more preferably, the polyglycol type epoxy resin is mixed with other epoxy resins, such as DGEBA with 5'
~50% by weight replacement. Alternatively, carbon functional silane represented by the following general formula may be added to 0.1
~3% by weight is added.

Y RS r X 3 However, in the above formula, Y is a hydrolyzable group, and X is an organic functional group. Silane, N-B-(aminoethyl)-ρ-
Create a compound with an organic functional group that can react with the Epoquine group, such as aminopropyltriethoxysilane.

The reason why the above-mentioned polyglycol type epoxy resin substitutes and carbon functional silane additives are preferable is that in either case, they are epoxy resin compositions having oil-absorbing functionality. The reason why the polyglycol-type epoxy resin substitute exhibits an oil-absorbing function is because it increases the polarity of the oil, and even if oil or fat adheres to the surface of the rare earth magnetic powder, the epoxy resin composition can surely penetrate to the surface. be able to.

On the other hand, in the case of a carbon functional silane additive, by reducing the surface tension of the epoxy resin composition, even if oil or fat adheres to the surface of the rare earth magnetic powder, the surface can be reliably wetted with the epoxy resin composition. This is because it can be done.

This is because if the epoxy resin is given an oil-absorbing function as described above, the rare earth magnetic powder can be bonded more reliably and firmly by the resin.

Next, the dicyandiamide referred to in the present invention is represented by NH j 82NC-NH-C3N, and the derivative of this compound is a dicyandiamide derivative represented by the following general formula.

@-NH-C-NH-C-NH2 R2NHNH However, in the above formula, R1 and R2 are aliphatic residues, and such compounds include 〇-tolyl biguanide, α-2・5
-dimethylbiguanide, α・ω-diphenylbiguanide, 5-hydroxynaphthyl-1-biguanide, α・α′
-bisguanylguanidinodiphenyl ether, phenylbiguanide, p-chlorphenylbiguanide, α-penzylbiguanide, α・ω-dimethylbiguanide, etc.

Cross-linking with the epoxy resin by the above compounds, such as dicyandiamide, can occur through four nitrogen-containing functional groups. For mixing with the epoxy resin, ketones or glycol ethers or, if necessary, water are used in combination. The epoxy resin composition completely dissolved in an epoxy resin usually has a pot life of 6 months or more, or 10 months or more at room temperature.

Incidentally, since the dicyandiamide derivative can lower the temperature by 10 to 30° C., the dicyandiamide derivative may be used in combination or alone as required. Furthermore, imidazoles, especially substituted imidazoles, may be optionally used as a crosslinking accelerator for dicyandiamide and/or its derivatives, and other additives such as antifoaming agents, plasticizers, rust preventives, etc. may be added as necessary. may be used without interfering with the intent of the present invention.

Next, the rare earth magnetic powder referred to in the present invention is Sm(Co).

CLl, Fe, M)n < (n, where M is 1f11 of an element belonging to Group ■, Group V, Group VI, or Group VII of the periodic table
or two or more kinds, such as Ti, Zr, Hf, and V.

Examples include Nb, Ta, Mo, Cr, W, and Mn. n
is generally a number from 5 to 9. ), or R1-x (Fe
ly, By) x (wherein R is Nd or/and Pr, X is 0.5 to 0.9 Y is 0.05 to 0.1
osm(Co, Cu.0).

Fe, M>n-based rare earth magnetic powder has a two-phase separated magnetic phase, and is made into a single crystal during alloy production, or a polycrystalline alloy is ground, magnetically formed, sintered, and aged to produce magnetic force. The target material is one that has been crushed to a size of about 5 to 80 μm. The rare earth magnetic powder has extremely high magnetic performance compared to SmCo5, Ae-Ni-Co, or 5roFe+2018, so even when used as a magnetically anisotropic resin magnet, the high performance as a resin magnet is maintained. However, the rare earth magnetic powder usually becomes magnetically anisotropic during the production of resin magnets.

One of the rare earth magnetic powders represented by R+-x (Fel-y, By)x is, for example, Ndo-+3 (FeO893, B
Oo, 0? ) Magnetically isotropic, quenched fine particles with an extremely fine crystalline magnet phase obtained by quenching an alloy having a composition of 0.87 and pulverized as necessary. Rare earth magnetic powder is primarily isotropic, so when it is difficult to make it magnetically anisotropic at the stage of making a resin magnet, use Sm(Co, Cu).

It is possible to obtain a resin magnet having extremely high magnetic performance compared to other known magnetic powders containing Fe, M) n-based rare earth cobalt.

Example The present invention will be described below along with Examples and Comparative Examples.

The epoxy resin and its crosslinking agent as examples and comparative examples according to the present invention were DGGBAll 1% butyl glycidyl ether modified DGEBA (hereinafter referred to as BGE-DGEBA).
), polyglycol type epoxy resin (hereinafter referred to as PGE),
Carbon functional silane (ρ-aminopropyltrimethoxysilane, hereinafter referred to as AMS), imidazole (hereinafter referred to as IMZ), 2-ethyl-4methylimidazole (2E
4MZ), imidazole acetic acid +! (IMZ-Ace),
Triethylenetetramine (TEA), dicyandiamide (hereinafter referred to as DICY), and a dicyandiamide derivative (guanide) having the following structure were used.

CH3 @-NH-C-NH-C-NH2 11I CH3NHNH Table 1 shows the combinations of the epoxy resin compositions according to the invention examples and the comparative examples. However, the blending ratio was set to a stoichiometric equivalent ratio assuming that one amino active oxygen reacts with an epoxy group according to a conventional method.

20℃, 200-400poise shown in Table 1
Sm (Co, Cu) having an average particle diameter of 16 to 17 μm was obtained by treating a liquid epoxy resin composition of 1% by weight with AMS.

After mixing 3% by weight of rare earth magnetic powder shown by Fe, Zr) 7.33 and putting it into a cylindrical cavity with a diameter of 10 mm,
It was molded under a pressure of 2 ton/cJ at room temperature in a KOe magnetic field to obtain a green compact with magnetic anisotropy in the axial direction.

The green compact was heated to obtain a resin magnet. Resin magnets were molded immediately after mixing, and the residual magnetic flux densities Br under a measured magnetic field of 25 KOe were all 7.0 to 7.4 KG, with fluctuations within 5%.

Next, the mixture of the rare earth magnetic powder and the epoxy resin composition was left at 30° C. for an arbitrary number of days, and then a resin magnet was manufactured using the same manufacturing method. The results of examining the obtained resin magnet Br under the same measurement magnetic field are shown in FIG. However, the rate of decrease in Br refers to Comparative Example 3, that is, IMZ-Ac as a crosslinking agent for epoxy resin, as is clear from the Br diagram immediately below.
Only in the case where e was used, the rate of decrease in Br with respect to the number of days the mixture was left was extremely small, similar to the examples of the present invention.

As mentioned above, the epoxy resin composition is liquid at room temperature (
If it is made solid at room temperature, the amino active hydrogen and epoxy groups are frozen and become inactive, so the rise of the curve in Figure 1 shifts to the right (in the long-term direction), but in this case, during the molding stage of the resin magnet, This is not preferable since it becomes necessary to recalibrate and melt the resin magnets, and as a result, the difficulty in maintaining and managing the resin magnet manufacturing equipment or in the workability is increased.

Next, the chemical resistance of the resin magnet manufactured immediately after mixing and 12
Table 2 shows the results of the irreversible demagnetization rate at 0°C.

tt F, 1800 VT: Hals magnetized, 120
It is the reduction rate (%) of the surface magnetic flux density from the initial value when left in air at 30°C at 120°C, and chemical resistance is calculated from the weight change (%) when left in each chemical at 30°C with respect to the initial value. It is something.

As is clear from the table, the mixture of rare earth magnetic powder and epoxy resin composition is less likely to affect the Br reduction of the resin magnet due to the thickening of the epoxy resin composition.
Ace (Comparative Example 3) is not preferred because of its high chemical resistance and irreversible demagnetization rate.

This is because DGEBA reacted with the acid of IMZ-Ace salt has a monofunctional property. In addition, Examples 1 to 4 of the present invention are the first
As shown in the figure (it is clear that the change in Br during the resin magnet manufacturing stage is extremely small and stable, yet it retains its function as a resin magnet equivalent to that of IMZs.

Next, Ndo, +3 (F po, 93
゜Bo, 0? ) Substantially isotropic fine pieces of 125 μm or less with an extremely fine crystalline magnetic phase obtained by rapidly cooling an alloy having a composition of 0.87 (medium phase, 1.5% by weight) Immediately after mixing with the epoxy resin compositions of Inventive Example 4 and Comparative Example 4 shown in Table 1, isotropic resin magnets were manufactured.

The apparent Br of the resin magnets with a density of 5.5 g/cd in a measured magnetic field of 25 K Oe was 5.3 to 5.
It was 7KG.

FIGS. 2(a) and 2(b) are electron micrographs of resin magnets according to the above-mentioned examples of the present invention and comparative examples. However, the dark part in the figure (the visible part is the voids or the epoxy resin composition. Although the density is the same, the present invention example (a) is different from the comparative example (b).
) is N do, +3()' depending on the epoxy resin composition.
eo, 93 Bo, 07) 0.87 It can be seen that the quenched fine pieces are extremely firmly bonded. Further, unlike in the comparative example, there is no evidence that some of the quenched fine pieces were mechanically crushed.

The reason for this is that even if the epoxy resin composition with reduced surface tension as in the example of the present invention is added in a small amount of 1.5% by weight, the surface of the rare earth magnetic powder can be more reliably wetted. This is because it also provides the lubricating effect of magnetic powder. Additionally, this fact shows that if the epoxy resin composition has an oil-absorbing function, it will be effective in suppressing oxidation from the surface of the rare earth magnetic powder and maintaining the function and reliability of the resin magnet. It's obvious.

Effects of the Invention The present invention relates to a resin magnet in which rare earth magnetic powder having high magnetic performance is bonded with an epoxy resin, while maintaining and ensuring reliability such as so-called chemical resistance and irreversible demagnetization rate of the resin magnet.
A resin magnet with extremely stable functionality can be provided.

[Brief explanation of drawings]

Figure 1 is a characteristic diagram showing the number of days a mixture of rare earth magnetic powder and epoxy resin composition is left standing and the rate of decrease in Br with respect to the initial value. It is a micrograph showing the bonding state of powder. Name of agent: Patent attorney Toshio Nakao (1 person) Figure 1 Figure 2 Procedural amendments July 7, 1985 1 Indication of the case 1986 Patent application No. 73552 2 Name of the invention Resin magnet 3 Amendments to be made Person: Relationship with JT Patent Application Address 1006 Oaza Kadoma, Kadoma City, Osaka Name (582) Representative of Matsushita Electric Industrial Co., Ltd.
Akio Tanii 4 Agent 571 Address 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture, Matsushita Electric Industrial Co., Ltd. ``Microphotograph that shows the grain structure''
I will correct it.

Claims (4)

[Claims] (1) A resin magnet in which rare earth magnetic powder is bonded with an epoxy resin, dicyandiamide, and/or a derivative represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ However, in the above formula, R_1 and R_2 are aliphatic residues. (2) The resin magnet according to claim 1, wherein the epoxy resin has oil absorption functionality and contains a polyglycol type epoxy resin and/or a carbon functional silane represented by the following general formula. YRSiX_3 However, in the above formula, R is an aliphatic residue, X is a water-splitting group, and Y is an organic functional group. (3) The resin magnet according to claim 1, wherein the rare earth magnetic powder is a rare earth cobalt magnetic powder represented by the following general formula. Sm(Co, Cu, Fe, M)_n However, in the above formula, M is one type or a combination of two types of elements belonging to Groups N, V, VI, and VII of the periodic table, and n is generally 5. An integer between ~9. (4) The resin magnet according to claim 1, wherein the rare earth magnetic powder is rapidly solidified fine particles represented by the following general formula. R_1_-_x(Fe_1_-_y, B_y)_x However, R is Nd or/and Pr, x is 0.5 to 0.9,
y is 0.05 to 0.10.