JPS62263612A - Resin magnet - Google Patents

Abstract

PURPOSE:To obtain a resin magnet capable of continuing and ensuring high reliability efficiently by using an oligomer having an alcoholic hydroxyl group in a molecule and an isocyanate regenerated body as the binder components of a liquid quenching Fe-B-R group (where R represents Nd or/and Pr) magnet blank. CONSTITUTION:An oligomer having an alcoholic hydroxyl group in at least a molecule and an isocyanate regenerated body are employed as the binder of a liquid quenching Fe-B-R group (where R represents R or Nd or/and Pr) magnet blank. Oligoether or oligoether ester or the like represented by formulae 1, 2 can be illustrated as the oligomer having the alcoholic hydroxyl group in the molecule. n and m in formulae represent integers, R1 an aliphatic residue, R2 hydrogen or an alkyl group and R3 an aliphatic, aromatic or alicyclic residue. The active hydrogen compound adduct of diisocyanate is used as the isocyanate regenerated body, and the isocyanate regenerated body, such as phenol, m-cresol, xylenol, etc., the temperature of thermal dissociation of which is kept within a comparatively low temperature range, is preferable.

Description

[Detailed description of the invention] Industrial applications! f The present invention relates to a resin magnet that is widely used in the mechatronics field as a member of pulse motors, servo motors, actuators, etc. For more details, see FF! obtained by liquid quenching method. -Fl -R system (R is Nd or/
and Pr) relates to a resin magnet composed of a magnet material and a binder.

Conventional technology Rare earth cobalt sintered magnets, such as Sm(Co.

CIJ, Fe, M)n (However, M is Group IV of the periodic table.

One or more elements belonging to group V, group ■, group ■,
(where n is generally an integer of 5 to 9) is formed into a cylindrical shape, and it is extremely complicated to make the magnetic anisotropy in the radial direction of the shape. The main reason is that anisotropy 1 occurs in the sintering process.
This is because a difference occurs in the expansion coefficient based on 1), and this difference in expansion coefficient is influenced by the culmness and shape of the magnetic anisotropy, but generally there is no choice but to deal with it by isotropy.

Therefore, the maximum energy product would normally be 20 to 30 MG.
Oe developed magnetic performance t) 5M G in the cylindrical radial direction
OP! It will decrease to a certain extent. Pulse motors, servo motors, and actuators that require even higher dimensional accuracy. Grinding is required after sintering in order to make it compatible with parts such as ethers, resulting in poor product yields (in addition to the fact that the main components are Sm and Co, there is a poor balance between economy and performance. Moreover, sintered products Since they are generally mechanically fragile, there is a risk that a portion of them may come off and have a serious impact on maintaining the functionality and ensuring reliability of pulse motors, servo motors, actuators, etc.

On the other hand, in the case of rare earth cobalt resin magnets, the resin that is the matrix can absorb the difference in the expansion coefficient of the rare earth cobalt that has been magnetically anisotropic in the radial direction, so a magnet that is magnetically anisotropic in the radial direction can be obtained. In recent years, if injection molded rare earth cobalt resin magnets are made magnetically anisotropic in the axial direction, the maximum energy product can be increased to 8 to 10 M G OF! It is known that the latter can be easily obtained. However, compared to sintered products, the density is reduced by approximately 30%, a high degree of dimensional accuracy is ensured, and mechanical fragility is improved. This is expected to be more preferable for magnets that require chromatography.

Next, we will explain the prior art related to a means for generating anisotropy in the radial direction of rare earth cobalt resin magnets. A magnetic yoke and a non-magnetic yoke are alternately combined to surround the cavity.
Either use a mold in which a magnetizing coil is placed on the outside, or use a mold in which a magnetizing coil is buried outside the cavity. In this method, a high-voltage, low-current type power source is used to generate a magnetic field of a predetermined strength within the cavity, and the magnetomotive force is increased by one.

However, in order to effectively focus the magnetic flux excited by the magnetizing coil from the outer periphery of the mold into the cavity by the yoke, the magnetic path length must be lengthened, especially for small magnets. In this case, a considerable portion of the magnetomotive force is consumed as leakage magnetic flux. As a result, it becomes difficult to achieve sufficient magnetic anisotropy in the radial direction.

As mentioned above, there are cases where rare earth cobalt resin magnets exhibit magnetic performance of −F rotation than rare earth cobalt sintered magnets when magnetic anisotropy in the radial direction is required. As a result, it has seven drawbacks: it is difficult to adequately respond to magnetic performance in the radial direction as miniaturization and weight reduction progress.

This is −qt formula Sm (Co, C+, +, Fe, M)n
These are the characteristics of sintered magnets and resin magnets for the rare earth cobalt. On the other hand, Sm(Co, Cu).

In the Fe-B-R system obtained by the same production method as rare earth cobalt such as Fp, M)n, :'I f
The coercive force of particles adjusted to about tm is generated by pinning due to domain wall movement, and because of the magnetic anisotropy of wood, rare earth cobalt 7 has the characteristics of both sintered magnets and resin magnets. It becomes t). Especially the standard atomic composition F
The particles, exemplified by e77, Ba, and Nd1s, are usually heated at 1,5 t, on/in a magnetic field of about 10 K Oe.
After compressing with a pressure knife of about cJ, 1000 to 120
It is used as a sintered magnet that develops coercive force by sintering it in an air stream at 0°C Δ and heat-treating it at 500 to 600°C. In this magnet, a BCC phase precipitates at the grain boundaries, and the surface of the magnet is Sm (C
o, Cu, FF! .

S) is much more difficult than the rare earth cobalt represented by M>n.

The present invention has been made in view of the above background.

Means for Solving Problems The present invention uses an oligomer having at least an alcoholic hydroxyl group in the molecule and an isocyanate as a binder for a liquid quenched Fe-B-1≧ system (where R is Nd or/and Pr) magnet material. t) using one playback.

Function First, the liquid quenched Fe-B-R system (where R is N tl or/and Pr) magnet material referred to in the present invention has the basic formula Nd
It has a composition represented by 1-X(Fel-y, By)X. (However, 0.5≦X≦0.9゜0.05≦Y
≦0.10) For example, standard atomic composition)'es+,)3
It refers to plate-shaped particles with a wall thickness of about 10 μm and several tens to hundreds of μm in the longitudinal direction, which are obtained by suitably pulverizing a molten alloy of S, Nde3 into ribbon pieces through an orifice and rolls in an Ar atmosphere.

These particles can be used, for example, in Orthohompic.
ic) system as well as tetragonal ('I' etragon
It is considered to have a microstructure in which extremely fine Fe-B-R ternary magnet phases are scattered in the al) system Fe5B, and is magnetically isotropic. These liquid quenched Fe-
The B-R magnet material is brought into an amorphous state when a rapidly cooled ribbon is obtained, and then heated above the crystallization temperature to precipitate the Fe-)1-R ternary magnet phase in the metastable Fe5B phase. It may be the one that has gone through the process t) or the final microstructure that is formed during liquid quenching.

As long as the properties based on the basic microstructure of the liquid-quenched Fe-B-R magnet material are not impaired, Si is added to the material.

Mo, A1. There is no problem even if other elements such as Co, Zr, Pd, Y, and Tb are mixed. Furthermore, liquid quenching Fe-
The B-R magnet material may be a material with a surface film formed on the surface of a dish molecular film or more, such as carbon functional silane. Examples of the carbon functional silane include γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β+aminoethyl γ-aminopropyltrimethoxysilane, and γ-metacaptopropyltrimethoxysilane.

Note that other organic compounds such as organic titanate compounds can also be used as appropriate.

Next, examples of the oligomer having an alcoholic hydroxyl group in the molecule as used in the present invention include oligoethers and oligoether esters represented by the following formulas (1) and (2).

R2R2R2 1l -4@-R+-◎-0-C-C-C-0+n-・-(1
)20HR R2R2R2 -lc @ -R+ -@-0-C-C-C-0-)
-nl 1 1 R20HR2 (in Japanese, n and m are integers, R1 is an aliphatic residue, R
2 represents hydrogen or an alkyl group, and R3 represents an aliphatic, aromatic or alicyclic residue.

The isocyanate regenerated product used in the present invention is an active hydrogen compound adduct of diisocyanate, and the isocyanate includes P-71 nylene diisocyanate, m-)T
, nylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, P-P
'-Schifte nylene diisocyanate, P-P'-diphenylmethane diisocyanate, P-P'-diphenyl ether diisocyanate, P-P'-Schiff T, nylsulfone diisocyanate, P-P'-benzophenone diisocyanate. Active hydrogen compounds that form adducts with these include amines, acidic sulfites, tertiary alcohols, lactams, mercaptans, enols, oximes, etc., and preferably fluorocarbons, alcohols, m- Thermal decomposition+a humidity temperature of regenerated isocyanates such as cresol and xylenol is in a relatively low temperature range. Furthermore, those into which an aromatic imide is introduced as the isocyanate compound are preferred. Such an aromatic imide can be prepared, for example, by combining an aromatic carboxylic acid anhydride and a diisocyanate with m-cresol, N
-N'-dimethylformamide, N-N'-dimethylacetamide, methylpyrrolidone or the like can be decarboxylated and produced in situ.

It is preferable that the oligomer and the isocyanate regenerated product have a stoichiometric ratio of the alcoholic hydroxyl group and the isocyanate group of the oligomer (OH/NC0=11).

Further, the binder component in the liquid quenched FeNd-B magnet material is preferably 1.5 to 5 parts dispersed.

EXAMPLES The present invention will be explained in more detail with reference to Examples and Comparative Examples.

(Magnet material) Atomic composition F obtained by melting in a high frequency melting furnace in an Ar atmosphere
ear, 86. A quenched ribbon piece is produced by continuously dropping Nd+3 alloy into the gap between the rolls through an orifice,
By appropriately crushing the quenched ribbon pieces, the thickness as shown in FIG.
A liquid quenched Fe-B-R magnet material was obtained. Table 1 is a characteristic table showing the results of qualitative analysis of Na-U by fluorescent X-ray analysis.

[Chapter] Table SS SM Buttocks Intermediate Small amount? On the other hand, Sm (COo, s
ea, CuQ, IOI, F po, 2+4. Zr
A rare earth cobalt having a standard composition of 733 (o, o+7) was prepared.

The specific surface areas of the liquid quenched Fe-B-R and rare earth cobalt are 0.070-/g and 0.1-g, respectively.
1On? /g. These were treated with the necessary amount of carbon funxysilane to form a monomolecular film on their surfaces. However, the carbon functional silane used was γ-aminopropyltrimethoxysilane.

FIG. 2 shows the results of differential thermal analysis of 30 m of the magnet material in air. As is clear from the diagram, liquid quenching FF! -B-
R (dotted line A in Figure 2) has better oxidation stability than rare earth cobalt (broken line B in Figure 2), but carbon functional silane treatment (solid line in Figure 2) C) is stabilized by

(Binder) As the oligomer having an alcoholic hydroxyl group in its molecule, oligoethers represented by the following formula (3) and having one different molecular weight were used.

(:, H3H○HH I 111 A, @ -C-@ -0-C-C-C-0+ n ・
...(3) l l1 l C1-138)] H However, since the -hysterium oligoether terminal is an epichlorohydrin compound, the terminal group is an epoxy group.

On the other hand, the isocyanate recalcification is as follows (4), (5)
, rn-cresol adduct of P-P'-Schiffenylmethane diisocyanate represented by formula (6), 1 mole of trimellitic acid and 2 moles of P-P'-diphenylmethane diisocyanate are decarboxylated. m-cresol adduct of amide imide diisocyanate obtained by decarboxylation of 1 mole of pyromellitic anhydride and 2 moles of P-P'-Schiff Tylmethane diisocyanate; An m-cresol adduct of Nato was used.

H ◎-0-C-N-◎-CH2-◎- H3 Cto)3 0H)1 @-0-C-N-◎-CH2-◎-N- H3 + 11 @-N-C-0- @ ・・・・・・(5)＼, H3 0 H II 1 ■-N-C-0-@ ・・・・・・(6)H
3. P-P'-Schiff, nylmethanediamine was used as the amine compound to be cured by the terminal epoxy group of the oligoether.

Above, the mixing ratio of oligoether and isocyanate regenerated product is based on the equivalent ratio of isocyanate group to terminal epoxy group and intramolecular alcoholic hydroxyl group, and the mixing ratio of oligoether and diamine is based on equivalent ratio of amine active hydrogen to terminal epoxy group. And so.

After curing the above binder component at 170℃ for 2 hours, TB
FIG. 3 is a characteristic diagram in which the glass transition temperature was determined using Method A and plotted against the molecular ends of the oligoether. In Figure 3, A represents imido diisocyanate, B represents amide imide diisocyanate, C represents P-P'-Schiff L, nylmethane diisocyanate, and D represents P-P'-Schif T, nylmethane diamine. .

When the oligoether becomes a polymer, the concentration of terminal epoxy groups becomes low, so an amine compound cannot maintain a high glass transition temperature, but an isocyanate regenerated product can maintain it.

(Moldability) A mixture of liquid quenched Fe-R-R and 3M mass % of oligoether/P-P'-diphenylmethane cyanocyanate regenerated material having different molecular weights was prepared with an outer diameter of 8 mm and an inner diameter of 5.511 mm.
I111 height 4 mm, density 5: 3~5, 5 g/
cnf green body. The radial crushing strength of this green body was determined according to Jl5-Z-2507, and the fluidity of the mixture was determined according to Jl5-Z-2502.

FIG. 4 shows a characteristic diagram in which the determined values are plotted against the molecular weight of the original oligoether. In FIG. 4, A indicates fluidity and B indicates green body radial crushing strength.

However, the fluidity is the ratio determined based on the fluidity of liquid quenched Fe-BR treated with carbon functional silane.

The figure shows that the fluidity of the mixture and the radial crushing strength of the green body depend on the molecular weight of the oligoether. That is, in order to ensure the molding workability of the mixture, it is desirable that the molecular weight of the oligoether is 900-F or more.

(Strength and demagnetization of TR stone) Oligoether with a different molecular weight from liquid quenched Fp-R-R/P-P'-diphenylmethane diisocyanate regenerated product or P-P'-SchifTnylmethanediamine triple salt %, the outer diameter is 8mm, the inner diameter is 5.5mm, and the height is 4mm.
mm s density 5, 3~5, 5 g/cn? After forming a green body, it was cured at 170° C. for 2 hours to obtain a resin magnet. Figure 5 shows the radial crushing strength t in an atmosphere of 130°C.
) is shown, and Figure 6 shows the magnetic flux amount (Ma
The demagnetization rate was calculated from In addition,
In FIGS. 5 and 6, A represents P-P'-Schiff T, nylmethane diisocyanate, and B represents P-P'-diphenylmethanecyamine. On the other hand, referring to the characteristics between the molecular weight of oligoether and the glass transition temperature of the binder shown in Figure 3, the mechanical strength and demagnetization rate of a magnet at high temperatures are significantly affected by the glass transition temperature of the binder. It is obvious that you will receive

The binder method of curing oligoether with isocyanate regenerant can ensure a high glass transition quality regardless of the molecular weight of the oligoether, and if you want to obtain an even higher glass transition point, This can be easily achieved by introducing a bimide group. From this, while ensuring work 11 (flow 11 of the mixture and radial crushing strength of the green body) at the stage of manufacturing the magnet, maintaining the reliability of the magnet.
It is clear that this is extremely effective in securing security.

Incidentally, when the oligoether is cured by the isocyanate regenerant, the active hydrogen compound attached to the isocyanate is thermally dissociated and liberated. However, since the magnet itself is generally a porous material with a relative density of about 75 to 80%, it remains in the binder and does not seriously affect the maintenance of reliability 11 of the magnet. Furthermore, since the active hydrogen compound added to the isocyanate can ignore dissociation at around room temperature, there is no need to take special care when storing it in a mixture state with liquid quenched Fp-BR or oligoether.

(Characteristics as a magnet) The density is 5.8 to 6.0 g from the mixture of liquid quenched Fe-B-R shown in Table 1 and oligoether/P-P'-Schiff, nilmethane diisocyanate regenerated product. /c- magnet was manufactured. Its magnetic performance is shown in Table 2.

Table 2 As shown in Table 2, the liquid quenched Fe-B-R magnet material has a slight
Even if trace amounts of elements such as Zr and Y are present, the magnetic properties are not significantly affected.

Next, FIG. 7 shows the relationship between the density and magnetic properties of the magnet. As shown in the figure, the magnetic performance of the liquid-quenched Fe-B-R resin magnet depends only on the density of the magnet. and isotropic 11
Maximum energy product of rare earth cobalt sintered stone with t 5 M
It is also possible to secure advanced performance that easily exceeds the level of G Oe.

Incidentally, FIG. 8 shows the relationship between the radial magnetic properties of an injection molded rare earth cobalt resin magnet that can be magnetically anisotropic in the radial direction and the outer diameter of the cylindrical magnet.

In Fig. 8, A is liquid quenched Fe-B-R, (density 5
, 5 g/cnt), and B indicates rare earth cobalt.

As shown in the figure, as the magnet becomes smaller in size, it becomes impossible to effectively focus the magnetic flux generated by the excitation coil, making it difficult to create magnetic anisotropy in the radial direction. This shows that rare earth cobalt resin magnets cannot be used satisfactorily as components for pulse motors, servo motors, actuators, etc., which require smaller size and lighter weight. However, it is clear that liquid-quenched Fe-Fl-R resin magnets are extremely useful because they are essentially isotropic and provide excellent magnetic performance. In the case of magnet materials with large magnetic anisotropy constants such as rare earth cobalt, it was necessary to use a low-viscosity liquid binder to promote magnetic anisotropy, but liquid quenched Fe-BR This is not necessary if the resin magnet is a resin magnet that can maintain and ensure a high degree of reliability extremely efficiently by using the oligoether and the isocyanate regenerant.

As is clear from the description of the effects of the invention, according to the present invention, it is possible to obtain a magnet that can continue and ensure high reliability extremely efficiently.

[Brief explanation of drawings]

Figure 1 is a micrograph showing the particle structure of the liquid quenched Fe-B-R magnet material, Figure 2 is a characteristic diagram showing the results of differential thermal analysis, and Figure 3 is the glass transition temperature versus molecular weight of oligoether. Characteristic diagram, Figure 4 is a characteristic diagram showing green body pressure strength and fluidity with respect to molecular weight of oligoether.
Fig. 5 is a characteristic diagram showing the molecular weight of the oligoether and the radial crushing elongation of the magnet, and Fig. 6 is a characteristic diagram showing the molecular weight and demagnetization rate of the oligoether. Figure S7 is a characteristic diagram showing the density and magnetic performance, and Figure 8 is a characteristic diagram showing the outer diameter of the cylindrical magnet and Br in the radial direction. Proxy Tanuki person's name Patent attorney Toshio Nakao et al.] Name No. 1 Fig. −+ to +5 (−*−−−−
- Fig. 5 Orico bunny pull weight +1h Fig. 6 Orico bunny pull amount Fig. 7 Age of age g/cyn3 Fig. 8

Claims (6)

[Claims] (1) Liquid quenched Fe-B-R system (where R is Nd or /
and Pr) A resin magnet using at least an oligomer having an alcoholic hydroxyl group in the molecule and an isocyanate regenerant as a binder component of the magnet material. (2) The resin magnet according to claim 1, wherein the liquid quenched Fe-B-R magnet material is treated with carbon functional silane. (3) The resin magnet according to claim 1, wherein the oligomer is an oligoether having a molecular weight of 900 or more. (4) The resin magnet according to claim 1, wherein the isocyanate regenerant comprises an aromatic isocyanate compound and active hydrogen. (5) The resin magnet according to claim 1 or 4, wherein the isocyanate regenerant has an aromatic imide residue. (6) The resin magnet according to claim 1, wherein the alcoholic hydroxyl groups of the oligomer and the isocyanate groups of the isocyanate regenerant are in an equivalent ratio.