JPS63289807A - Compound and method for manufacture of bonded magnetic - 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] [Industrial Application Field] The present invention relates to a molded article having magnetic performance,
In the molded article, magnetic particles are bonded to each other by an organic substance. The invention therefore relates to a process for manufacturing so-called bonded magnets. The invention also relates to compositions for making moldings with magnetic properties.

[Conventional technology]

Bonded magnets made from compositions of organic materials, such as organic polymeric materials, and particles of magnetic material are well known. Commercially available magnets of this type are usually made from compositions consisting of a mixture of thermoplastic organic polymers and particles of magnetic material. For example, a composition comprising a mixture of a thermoplastic organic polymer and magnetic material particles is molded in a plastic molding machine (eg, an injection molding machine, an extrusion molding machine). This composition may also be formed by compression molding.

The composition is molded while the thermoplastic polymer is in a fluid state and immediately cooled and solidified. In addition, when the thermoplastic organic polymer is in a fluid state, the performance of the magnet can be enhanced by exposing the composition to a magnetic field to orient the easy magnetization direction of the magnetic particles in a certain direction. Application of the magnetic field is continued until the organic polymer is cooled and solidified. After complete cooling and solidification, the magnetic field is removed as it is no longer necessary to maintain the orientation of the particles in the composition. The magnet thus molded is taken out from the plastic molding machine.

The organic polymer in the composition used to make bonded magnets is a polyolefin. For example, polyethylene, polypropylene, but particularly preferred for such compositions are polyamides, one of which is nylon. Particularly preferred is nylon-6. For example:
JP-A-59-94406 describes a composition comprising a synthetic resin and magnetic powder surface-treated with a coupling agent. The magnetic particles are ferrite or a rare earth cobalt intermetallic compound, and the synthetic resin used is polypropylene, polyvinyl chloride, or polyamide such as nylon-6, nylon-11, or nylon-12. Compositions using polyamides such as nylon-6 and nylon-6,6 are also disclosed in JP-A-60-216
It is described in Japanese Patent Application Laid-open No. 524 and Japanese Patent Application Laid-Open No. 61-59705.

Shizhuangite, which is made of a composition made of an organic material and has the property of being resistant to deformation even at high temperatures, is obtained using a composition made of a crosslinkable organic material (for example, a thermosetting resin). In the production of magnets made of such compositions, a composition in which a crosslinking agent that induces crosslinking of the organic material is added as an additive to a crosslinkable organic material and mixed with magnetic material particles is used in a plastic molding method. The organic material is then cross-linked, resulting in a bonded magnet consisting of a solid organic resin cross-linked with particles of magnetic material. When the organic material is in a fluid state, the composition may be exposed to a magnetic field to orient the easy magnetization direction of the magnetic particles. By doing so, the magnetic properties of the magnet can be improved. In that case, the applied magnetic field is maintained at least until the crosslinking reaction is sufficiently effective to solidify the composition to such an extent that the oriented particles are not disturbed even in the absence of a magnetic field. If the applied magnetic field is removed while the organic material is still in a flowing state, the magnetic particles in the organic material will become misoriented as adjacent ones repel each other.

The manufacturing method of bonded magnets made of crosslinkable organic materials includes:
The following publicly known materials are available. First, JP-A-60-220
No. 905 describes a method for producing a bonded magnet made from a composition consisting of an epoxy resin, rare earth magnet powder, and a fatty acid ester as a lubricant. Next, JP-A-60-22-0906 describes a method for manufacturing a bonded magnet made from a composition consisting of an epoxy resin, rare earth magnet powder, and a fatty acid amide as a lubricant. As a third example, JP-A-60-2
There is a publication No. 06111. This patent describes, as a specific example, a bonded magnet made from a composition consisting of a bisphenol A novolac epoxy resin, a diluent and a magnetic powder of Sm-Co intermetallic compound. Fourth
An example of this is JP-A-60-183705.

This patent relates to a method for producing a bonded magnet using a composition comprising ferrite powder surface-treated with a surfactant and unsaturated liquid polyester.

[Problem to be solved by the invention]

However, magnets made from compositions where the organic polymeric material is a thermoplastic such as nylon or polyolefin have the following drawbacks. This is because polyolefins and nylons have relatively low glass transition temperatures. As a result, magnets made from compositions made of polyolefin or nylon are distorted and deformed.

This phenomenon occurs as a result of repulsive forces between oriented magnetic particles in the magnet, especially when exposed to strong magnetic fields. If these things happen while the magnet is in use, it will have a significant impact on the equipment that incorporates the magnet. For example, the glass transition temperature of nylon-6, nylon-11, and nylon-12 is 62.5°C, 146°C, and 137°C, respectively.
It is. Therefore, the limit temperature for use of magnets using such resins is relatively low. Such a low service limit temperature is believed to be lower than the actually required temperature. Additionally, shaping the composition requires heating the organic polymer until it becomes fluid. However, the temperature is quite high and has undesirable effects on the performance of the magnetic particles, such as oxidation, during molding. Also, if you want to obtain a bonded magnet with high magnetic performance,
It is necessary to use a composition with a high filling rate of magnetic particles. Such compositions have a high viscosity when molded, making molding very difficult, if not impossible. In order to mold such compositions, the organic polymer must be brought into a fluid state, which requires extremely high temperatures. However, doing so will have undesirable effects on the properties of the magnetic material.

Generally, crosslinkable resins have a high glass transition temperature, so bonded magnets using this resin can be used at higher temperatures than bonded magnets using thermoplastic organic polymers.

However, magnets using such crosslinkable resins also have the following drawbacks. First, magnetic materials, whether ferrite, rare earth elements, or transition metals, are very expensive. Therefore, it is especially desirable to reuse defective or defective products during molding, or spools and runners from injection molding, protruding parts from compression molding, etc., which are normally thrown away. However, once the organic materials in the composition are crosslinked, they cannot be reused using any plastic processing technique. Therefore, there are defective and defective products.

Otherwise, the magnetic material contained in the protruding parts is completely wasted. Furthermore, in manufacturing magnets using such compositions, productivity is limited by the speed of crosslinking. The productivity is further determined by the fact that the crosslinking reaction must proceed in the mold of a molding machine, such as the mold of an extrusion molding machine, to such an extent that the composition does not lose its shape at all when removed from the mold. The pace is also determined by necessity. Further, when a magnetic field is applied to orient the easy magnetization direction of the magnetic particles, the magnetic field must be continued to be applied until the composition undergoes a crosslinking reaction and is sufficiently solidified. In other words, it means that the oriented magnetic particles can maintain their orientation even if no magnetic field is applied.The crosslinking reaction has a finite time.It takes several minutes to obtain an effective amount of crosslinking. The productivity of this process is therefore severely limited, and it is both inconvenient and uneconomical to continue applying a magnetic field for such a long time.

The present invention has been made to solve the drawbacks of the known techniques as described above, and its purpose is to provide a highly productive and economical manufacturing method for manufacturing bonded magnets that can be used up to relatively high temperatures. and to provide a composition suitable therefor.

(Means for Solving the Problems) The present invention provides a method for manufacturing a bonded magnet using a composition comprising a crosslinkable organic material and magnetic material particles.

According to the present invention, one of the molded articles having magnetic properties is made from a composition consisting of a crosslinkable organic material that can be handled as a solid melt, magnetic material particles, and optionally an additive that promotes crosslinking of the organic material. Two manufacturing methods are provided. This manufacturing method consists of the following manufacturing steps.

(1) Molding the composition in a mold at a temperature at which the organic material is in a fluid state.

(2) Cooling the molding composition until the organic material solidifies.

(3) Crosslinking the organic material in the molding composition thus molded to obtain a crosslinked material.

Among the manufacturing steps according to the present invention, manufacturing step (1) is performed at high temperature. This process is quick, and if the manufacturing process (2)
The composition remains in the manufacturing process for just a short while before moving on to the manufacturing process (1)
Even if the temperature is maintained at high temperatures, the amount of crosslinking of the organic material is thought to be very small. As a result, molding defects or parts that would normally be discarded, such as spools and runners in injection molding or flashings and extrusions in compression molding, can be reused. therefore,
The manufacturing process wastes little or no expensive magnetic material. Furthermore, this manufacturing process requires only a short time to mold, and it takes much less time to cool the molded composition than to cause the crosslinking reaction, so the productivity of this manufacturing method is high. It will be very expensive.

The manufacturing method according to the present invention described above is for an isotropic magnet in which the direction of easy magnetization of the magnetic particles is not oriented. Another application example is anisotropic magnets.

The manufacturing method of this anisotropic magnet (hereinafter referred to as manufacturing method -■)
consists of the following manufacturing process.

(1) Molding the composition in a mold at a temperature at which the organic material is in a fluid state.

(2) Applying a magnetic field to the composition at a temperature at which the organic material is in a fluid state.

(3) Cooling the molding composition until the organic material solidifies.

(4) Crosslinking the organic material in the molding composition thus molded to obtain a crosslinked material.

In the production method-H of the present invention, application of a magnetic field is not necessarily required when crosslinking. The shaped composition is
It is cooled to solidify the organic material therein. In the molding composition after cooling, since the organic material is solid, the magnetic particles maintain their orientation even without a magnetic field. Maintaining the magnetic field is only necessary during the cooling step until the organic material in the as-formed composition reaches a solid state.

In the manufacturing method according to the present invention - manufacturing step (4),
The organic material in the molding composition is crosslinked. If the organic material in the composition becomes fluid during this crosslinking reaction, the magnetic particles in the composition may repel each other and cause the molded composition to lose its shape or the finished bonded magnet to be In order to prevent such repulsion between magnetic particles, it is best to perform the cross-linking reaction while the organic material is solidified. Alternatively, the magnetic particles may be demagnetized before the cross-linking reaction occurs. Even if the organic material in the composition is then brought into a somewhat fluid state to crosslink, there is little or no reduction in the magnetic performance of the bonded magnet because the magnetic particles no longer repel each other. A requirement for all methods - ■ is that the shape of the composition must be retained during the crosslinking reaction. After the crosslinking reaction is completed, the oriented and demagnetized particles of magnetic material are It is magnetized by applying a magnetic field again.

Although the organic material in the composition used in the present invention has a solid surface, melt molding can be applied thereto. Generally speaking, organic materials are solid at around room temperature (approximately 25° C.), but have a melting point. therefore,
At high temperatures, it becomes a fluid and can be melt-molded. The organic material or composition is one that is melt-molded by a plastic molding machine (eg, an injection molding machine, an extruder, a compression molding machine).

The organic material in the composition can be a solid monomeric material or a solid polymeric material.

The composition may consist of a mixture of two or more monomeric materials, a mixture of two or more polymeric materials, or a mixture of one or more monomeric materials and one or more polymeric materials. Good too.

When the organic material in the composition is a 7-mer material, the monomer material must have a sufficiently high molecular weight for the composition to be solid at around room temperature. The monomer material preferably contains ethylenically unsaturated groups, more preferably two or more such groups. This is because such groups aid in crosslinking reactions.

Examples of suitable organic monomer materials include: 1.3-Diallylnylia.

HzC-CH-C1h-NH-Go-NH-CL-CI
=CHz9-vinylcarbazole.

CH Tomi CH.

Penta-erythritol tetramethacrylate.

CH3C(CHz-0-GO-C=CHz)43.9-divinyl-2,4,8,10-tetraoxaspiro-(5,5
) - Undecane.

4. Adduct of 4'-diphenylmethane diisocyanate and hydroxyethyl methacrylate.

can be mentioned.

Examples of organic polymer materials that are solid and can be melt molded include ethylenically unsaturated polyester resins and epoxy resins.

As a suitable epoxy resin, There is bisphenol A. The structural formula is shown below.

And epoxidized phenol formaldehyde novolacs are also promising. The structural formula is shown below.

In the above two structural formulas, It is.

Epoxy resins typically contain a curing agent with multiple hydroxy groups. An example of a suitable curing agent is phenol formaldehyde novolac.

OH There is.

The composition can and should contain additives that crosslink or promote crosslinking of the organic materials in the composition. However, it is of course possible for the crosslinking reaction to proceed without the additive. Particularly when the organic material contains ethylenically unsaturated groups (e.g. polyester resins or acrylic materials), suitable substances for such additives include peroxides and e.g. Included are radical initiators such as azo compounds such as isobutyronitrile. If the organic material is an epoxy resin, it may contain an additive that catalytically promotes the reaction between the epoxy resin and the curing agent.

If the composition contains additives that serve to initiate or promote crosslinking reactions, care must be taken in the combination of organic materials and additives. In this way,
Manufacturing step (1) in the manufacturing method of the present invention is performed at a temperature at which the organic material is in a fluid state. The amount of crosslinking that occurs when the organic material is in a fluidized state at elevated temperatures is preferably kept to a minimum, if at all, to an extent that would prevent reuse of the composition. And when the composition contains such crosslinking additives, the additives should be selected to be active enough not to cause undesirable amounts of crosslinking at molding temperatures. The additives chosen will of course depend on the organic materials in the composition and, in particular, on the temperature at which they are shaped in the manufacturing process according to the invention. In fact, the appropriate additive for one organic material is
It may not be entirely suitable for different organic materials that can only be melt-formed at higher temperatures. This is because at higher temperatures an unacceptably large amount of crosslinking reaction occurs during melt forming.

A preferred combination of an organic material and an additive should be selected after carefully examining the behavior of the organic material during melt molding and the thermal decomposition characteristics of the additive. However, an example of a suitable combination of additives and organic materials is a melting point of 4.
3.9-divinyl-2,4,8,10-tetraoxaspiro-(5,5)-undecane at 2°C and azo-bis-isobutyronitrile, which decomposes into radicals at a temperature of about 70°C or higher. and a combination of 9-vinylcarbazole, which melts at 65°C, and azobis-dicyclohexanecarbonitrile, which decomposes into radicals at about 90°C or higher.

The term "magnetic material" means a material that is magnetic or capable of being magnetized. Therefore, the magnetic material may not itself be magnetized. Just when the composition is manufactured,
Any material may be used as long as it is magnetized by application of a magnetic field. There is no particular restriction on the size of the particles of the magnetic material, but the particle size is preferably in the range of 0.5 to 200 μm.

As an example of suitable magnetic materials, barium ferrite (Ba
There are ferrite materials such as 0.6F ex O:+) and strontium ferrite (Sr0.6Fe, O,). Other examples include intermetallic compounds of rare earths and transition metals that can be used in the present invention and yield bonded magnets with high magnetic performance.

The rare earth metals that are raw materials for such magnetic materials include Sm,
Ce, La, Y, Nd, Pr, Gd; suitable transition metals include Fe, Co, Ni.

Examples include Zr, Hf, Cu, and Ti. Intermetallic compounds are generally represented by the general formula RCo or R2C0+t. Here, R is at least one rare earth metal. Sm is an example of a rare earth metal that forms an intermetallic compound. Examples of intermetallic compounds are generally S
mCo, ,Sm.

A compound represented by the compositional formula Co, is known. These compositional formulas are not exact chemical formulas of rare earth-transition metal intermetallic compounds. This is because elements other than Sm and Co may also exist in the compositional formula. By the way, in Japanese Patent Application Laid-open No. 60-227408, Sm (Coo,
b7z Cuo, ogF eo, tzZro,. 2B)
Rare earth-transition metal intermetallic compounds having 13 composition formulas are described. JP-A-60-220905 describes a rare earth-transition metal intermetallic compound having the following compositional formula.

That is, S m (Coo, btz Cuo, oeF
e o, zzZ r o, ozs) l:ls+
S mo, 7sYo, zs (Coo, hsCuo,
osF eo, zsZ r o, oz) 7.81
Smo, 8. CeO, +9 (Coo, 6, Cuo, oh
F eo, 3+Z ro, oz) 7.6.

Other examples of magnetic materials include intermetallic compounds based on Nd-Fe-B, consisting of at least one rare earth metal and at least one transition metal. As an example, Japanese Patent Application Laid-Open No. 60-220905 also states that N d (F e
o, qos Bo, 095) 3.67 is described. Still other examples include the following intermetallic compounds. That is, Sm(Co0967Cu
o, osF e o, zzZ r O, 03) 7.6
1Bm (Coo, 7nCuo, +oF eo, +sT
io, o+) 1. t *Sm (c Oo, bqC
uo,, 1OFeo, zoHf o, o+)? ,01
Ce (Coo, iwCuo, 11F' eO, lI
z r 6.1+1) h. .

S, mo, s Pro, s Cos, Sm
o, s Ndoo, CEO, + (Coo, ht
cuo, osF e o, zsZ r O,0ri s
, :+s and Nd+4Fes+Bs.

The composition may of course include one or more organic materials, one or more particles of magnetic material, and if necessary one or more additives to aid in the crosslinking of the organic materials.

The proportions of organic material, additives that cause or promote crosslinking, if any, and magnetic material particles in the composition may sometimes vary widely; generally speaking, the proportion of magnetic material is The higher the moldability, the better. This is because by increasing the amount, the magnetic performance of a bonded magnet made from the composition improves. Generally the proportion of magnetic material in the composition is at least 50% by weight
(It should not be, preferably 80% by weight or more. The preferred optimal composition range of the magnetic material is 80 to 9% by weight.
It is 5% by weight.

The amount of organic material in the composition ultimately depends on its ability to be melt molded in a plastic molding machine. And, generally speaking, at least 5% by weight of organic material must be included in the composition to be possible. The optimum range for the content of organic material is 5-20% by weight.

The amount of additive that causes or promotes crosslinking will depend, at least in part, on the nature of the additive and the nature of the organic material, but generally between 0.01 and 5% by weight of the composition will be sufficient. When the material contains ethylenically unsaturated groups, such as polyester resins and acrylic agents, and the additive is a radical initiator, the amount of additive in the composition is generally 0. 01-2% by weight. Even when the organic material is an epoxy resin, the amount of additives is generally 0.01 to 2% by weight.

The higher the amount of additive, the faster the organic material crosslinks.

Each component in the composition is kneaded in a suitable manner.

For example, when each component is in the form of fine particles, it may be kneaded using a suitable device for kneading fine particle materials.

A preferred method of producing a particularly homogeneous composition of organic material and magnetic material particles is to mill the composition under high shear, for example in a twin roll mill at a temperature at which the organic material softens. The mixture is then repeatedly passed through the cavities of the roll mill.

If desired, additives that cause or promote crosslinking may be added to the mixture in the mill at the end; This is a very convenient method. Since the effect of mixing additives is relatively short-lived, a slight crosslinking of the organic material occurs during kneading; for this reason, additives should preferably be added at the final stage of kneading. It is.

Alternatively, the components in the composition may be mixed in the presence of a liquid diluent. The liquid diluent is removed once its mixing role has been completed.

The liquid diluent helps to homogeneously mix the components in the composition and is later removed from the composition.

For example, if the diluent has a low boiling point, it is removed by evaporation.

When the organic material in the composition is a monomeric material or even when it is a polymeric material, kneading the components in the composition under high shear and the melt forming process that follows kneading can cause the organic material to flow. This can be facilitated by including in the composition a small amount of a polymeric material that can be dissolved or dispersed in the organic material when in the state or liquid state.

The inclusion of a small amount of such polymeric material facilitates molding of the composition, which contains a high percentage of magnetic material particles and is melt moldable in a plastic molding machine.

As a specific example of the present invention, a composition comprising the following components is provided.

(1) An organic material that can be melt-molded and cross-linked.

(2) Magnetic material particles.

(3) Polymeric materials that can be dissolved or dispersed in organic materials when the organic materials are in a fluid or liquid state.

and, if necessary, (4) additives that cause or promote crosslinking of organic materials to create crosslinked materials.

The polymeric material is generally a copolymer containing functional groups that have an affinity for magnetic particles. The polymeric material improves the wetting of the magnetic particles with the organic material. Suitable such polymers are copolymers of polyvinyl butyral and polyvinyl alcohol, copolymers of polyvinyl chloride, polyvinyl acetate and polyvinyl alcohol, copolymers of polyvinyl acetate and polycrotonic acid, copolymers of polyvinylidene chloride and polyacrylonitrile. be. Desirably, the composition contains 0.5 to 5% by weight of such polymeric material, and the composition may also contain one or more such polymeric materials.

The composition can be melt molded and molded using any suitable plastic molding machine such as an extruder, injection molding machine, or compression molding machine.

When carrying out the present invention by extrusion molding, the composition is first put into an extruder. The composition is then heated to bring the organic material into a fluid state, extruded using a suitable mold, and cooled near the exit of the mold to solidify the organic material. The molded product is then removed from the mold. When creating an anisotropic magnet, a magnetic field is applied to the composition in an extruder mold while the organic material is in a fluid state. As a result, the magnetic material particles are oriented in the direction of the magnetic field. The magnetic field is applied by an electromagnet placed in close proximity to the extruder mold. In the molding process, the molding temperature must not be excessively high. It is also important to keep the crosslinking reaction as low as possible by keeping the time that the organic material is in a fluid state relatively short. This is because by doing so, defective or waste products from molding can be reused.

The molding step according to the invention and the optionally applied magnetic field orientation step can likewise be carried out in an injection molding machine with a suitable mold when the organic material in the composition is in a fluid state. can. If desired, an electromagnet may be mounted in close proximity to the mold and serve to orient the particles of magnetic material in the direction of their easy magnetization. If it is formed,
It is cooled and removed from the mold.

The composition may also be formed by compression molding. In this case, the composition is placed in a suitable mold, heated to bring the organic material into a fluid state, compression molded in the mold and finally cooled in the mold. In this case as well, it is desirable that an electromagnet be mounted close to the mold in order to orient the magnetic material particles in the direction of easy magnetization.

When the molding process is performed in a magnetic field, the magnetic field is applied to orient the magnetic material particles in the direction of easy magnetization, but the magnetic field is applied to maintain the orientation of the magnetic particles even when the molded product is cooled. It is necessary to continue applying . Application of the magnetic field must continue until the organic material in the composition is sufficiently solidified to maintain the orientation of the magnetic particles without the aid of a magnetic field. The organic material in the shaped composition is crosslinked to obtain a crosslinked resin.

Crosslinking of the organic material is performed by heating the molded article. However, since the organic material becomes fluid when heated, it is necessary to maintain the shape of the molded composition. It is believed that the shape can be maintained by placing the molding composition in a suitable mold. Alternatively, the crosslinking reaction may be carried out while the organic material is in a solid state. By doing so, the shape of the molding composition is maintained. An appropriate method for realizing such solid crosslinking is electron beam irradiation. In this case, the crosslinking of the organic material in the composition will be influenced by the presence or absence of additives that cause or promote said crosslinking. Crosslinking can also be carried out by irradiating the molding composition with gamma rays. For example, crosslinking can be achieved by gamma radiation provided by a Co'' radiation source. Crosslinking is likewise influenced by the presence or absence of additives that cause or promote crosslinking. It may be performed later.By doing so, it is possible to improve the utilization efficiency of the molding machine and shorten the time of the molding process.

The shape of the composition can be maintained by partially crosslinking the material in the composition when it is solid. for example,
The organic material on the outer surface of the molding composition can be crosslinked by electron beam irradiation or gamma ray irradiation even if the organic material is solid. This outer surface is solid and helps maintain the shape of the composition when the composition is heated to high temperatures to complete crosslinking.

When the magnetic material particles in the molding composition are already in an oriented state, it is very advantageous to carry out the crosslinking while the composition is in the solid state. If the organic material becomes fluid before or during crosslinking, for example by heating, adjacent magnetic particles will repel each other and disturb their orientation, reducing the performance of the bonded magnet.

Even when the crosslinking of the organic material in the molding composition is carried out in the solid state, the crosslinking reaction by heating also takes place. Therefore, if the crosslinking reaction in the solid state is to be carried out sufficiently to prevent the composition from softening even after crosslinking by heating, and to maintain the oriented state of the magnetic material particles.

Prior to the crosslinking reaction of the molding composition, the magnetic material particles oriented in the direction of easy magnetization may be demagnetized by an appropriate method. For example, demagnetization by an alternating magnetic field can be considered. Although it is not necessary to completely demagnetize the magnetic material particles, it is desirable to demagnetize them to some extent. A certain degree means that the organic material exhibits a state close to fluidity during crosslinking, but even then there is only a slight repulsion between the magnetic material particles. When crosslinking is carried out at a temperature at which the organic material exhibits a state close to fluidity, the magnetic material particles are not magnetized even under such fluidity, so there is no repulsion between adjacent particles, and the oriented state is maintained. It's amazing how much it has fallen.

After the crosslinking reaction of the organic material is completed, the demagnetized magnetic material particles are re-magnetized.

〔Example〕

The present invention will be explained in detail by examples. However, the word "parts" hereinafter means parts by weight.

The following components constituting the composition were mixed by hand to form a somewhat uniform mixture.

Magnetic particles: Sm (c Oo, hrz F eo, z
zc uo, osZr,. XI) 91.4 parts of powder of a. 33 parts Polymer material: Copolymer powder of vinyl butyral and vinyl alcohol (trade name Pioloform BN 18, WackerCh
emie GmbH) 1.26 parts Silica powder (trade name Aerosil 0X50) 0.2 parts Calcium stearate 0.17 parts Bleached Monton wax 0.17 parts 3-(3,4
-dichlorophenyl)-1,1-dimethylnylia 0.05 part The mixture was then charged into a twin roll mill at a temperature of 90°C and repeatedly passed through the mill gap to form a plastic sheet. The presence of polymer helped sheeting. The sheet was rolled with a twin roll mill at a temperature of 80°C to a thickness of 0.1 m, and then the sheet was placed in a mold and pressed at a temperature of 110°C.
．． It was thinned to a thickness of 5mm. The sheet was further divided into six small sheets of the same size.

One of the small sheets was placed in a mold placed between the balls of a 23.5 KC electromagnet and rapidly heated to 140°C and then rapidly cooled to room temperature. At 140° C., the organic material in the composition melts and the magnetic particles become oriented under the applied magnetic field. Even if the sheet formed in this way is crosslinked, the degree of crosslinking is very small, so it is possible to remelt a part of the sheet and use it. Furthermore, the sheet was placed between the balls of an electromagnet, and an alternating current magnetic field was applied to demagnetize the magnetic particles.

The sheet is then placed in a mold for 170 min for crosslinking of the organic material.
It was heated for 30 minutes at a temperature of °C. Finally, the sheet was magnetized with a magnetic field of 23.5 KG between the balls of an electromagnet. The sheet-like bonded magnet (Bl()n
+ax was 4.5 MGOe.

Comparison Example 1 One of the small sheets obtained in Example 1 above was treated using conventional processes to orient the magnetic particles and crosslink the organic material.

The sheet was placed in a mold placed between the balls of a 23.5 KG electromagnet and heated at 170° C. for 30 minutes. At this temperature, the organic material in the cast material initially melts, and the magnetic particles are oriented in the direction of easy magnetization. The organic material is then crosslinked. The sheet is cooled to room temperature and removed. (BH)a+ax of the obtained sheet-like bonded magnet is 5.2MGOe
Met.

Since the organic material of the sheet has been completely crosslinked, it is no longer possible to reuse any part of the sheet. This indicates that defective products and unnecessary parts that would normally be produced cannot be reused and must be thrown away. Moreover, the following was clarified by this comparative example. That is, in the conventional method, it is necessary to continue applying a magnetic field for an extra period of time in order to ensure the orientation of the magnetic particles.

One of the small sheets obtained in Example 1 was magnetically oriented as in Example 1. Therefore, the organic material is uncrosslinked in the sheet, but the magnetic particles are oriented. The sheet was heated at 170° C. for 30 minutes without being held in a mold. The sheet softened and expanded many times its original volume as a result of repulsion between adjacent magnetic particles. After heating, the sheet had bubbles, was brittle, and had very low magnetic performance. This comparative example shows the following. That is, if the orientation of the magnetic particles occurs before cross-linking of the organic material, if the magnetic field is not maintained or the oriented magnetic particles are not demagnetized first, the organic material will reach a fluid state before cross-linking. If heated, the orientation will be disturbed.

The process of Comparative Example 2 of Kasa Earthworks was repeated with the sheet held in the mold. Heating was at 170'C for 30 minutes. The (BH)wax of the obtained sheet was 3MGOe. This value indicates that heating a sheet with oriented and magnetized magnetic particles in an uncrosslinked organic material causes the magnetic particles to lose their orientation when the organic material melts. This is because the orientation of magnetic particles is not maintained by a magnetic field.

One sheet of paper One of the small sheets obtained in Example 1 was oriented in a magnetic field as in Example 1, and then demagnetized to obtain a demagnetized sheet. The organic material in the sheet is uncrosslinked, but the magnetic particles are oriented. The sheet was then precisely machined into the required shape. The parts that are cut off by machining can be reused because the organic material inside them is uncrosslinked. Fes was sprayed onto the sheet. The varnish solidifies and becomes a film 170
Can withstand temperatures of ℃. Furthermore, the sheet was heated at 170℃ for 30 minutes.
Heated for 1 minute to crosslink the organic material in the sheet.

The shape of the sheet remained the same. 2 between the poles of the electromagnet
The results of magnetization and measurement by applying a magnetic field of 3.5 KG (B
H) a+ax was found to be 4.3 MGOe.

The process of Capsule Foundation Example 2 was repeated without the varnish coating. The sheet obtained no longer had the desired shape. This is because the machined edge has a sheet of 1
This is because the sheet became round when heated to 70° C., or the organic material in the sheet became fluid before it was crosslinked.

91 The following components constituting the composition were mixed by hand to form a somewhat uniform mixture.

Magnetic particles: 187 parts of the same as used in Example 1 Organic material: 18.7 parts of powder of adduct of 4.4''-diphenylmethane diisocyanate and hydroxyethyl methacrylate Polymer material: Powder of copolymer of vinyl butyral and vinyl alcohol ( Product name: Pioloform BN 1B, WackerCh
(manufactured by emie GmbH) 3.1 part Next, the mixture was put into a twin roll mill at a temperature of 80°C, and the mixture was repeatedly passed through the gaps of the mill to form a plastic sheet. This helped sheet manufacturing. Here, 0.2 part of 1,1'-azo-bis-(cyclohexane carbonitrile), which is a radical initiator, was added and kneaded for further 1 minute. The plastic sheet was then removed from the mill and rolled to a thickness of 0.7++ m at a temperature of 60°C using a zero-order twin roll mill cooled to room temperature, and then placed in a mold and rolled at a temperature of 80″C to a thickness of 0.511I11. The sheet was divided into five equal size small sheets.

One of the small sheets was sandwiched between the poles of a 23.5 KG electromagnet, and the temperature was rapidly raised to 100° C. and then rapidly cooled to room temperature. At 100° C., the organic material in the composition melts, so the magnetic particles can be oriented in the presence of a magnetic field. The cooled sheet could be reused. This indicates that even if some crosslinking occurred, it did not occur to the extent that it would prevent reuse of the sheet.

The sheet was then irradiated with CohO gamma rays at room temperature to crosslink the organic material in the solid state. Irradiation is 6
This was carried out for a sufficient time to crosslink the resin, which has a glass transition temperature of 0°C. The sheet was then heated to a temperature of 120°C. At this temperature, the sheet softens slightly, but not so severely that it deforms or disturbs the orientation of the magnetic particles.

Heating at 120°C continued for 5 minutes to further progress crosslinking.

The sheet then developed to have a glass transition temperature of 100°C. (BH)I of this sheet! Iax is 5.0
MC: Oe.

Actual Example 3 Other small sheets obtained in Example 3 were used and subjected to the same orientation treatment under a magnetic field as in Example 3. After cooling to room temperature, it was demagnetized by a damping magnetic field between the poles of the electromagnet.

Furthermore, the sheet was subjected to a 1 M
The electron beam was irradiated with a dose of rad. The sheet was then heated at a temperature of 120° C. for 5 minutes to cause further crosslinking. The sheet was then magnetized as in Example 1 and the (BH)IIIax was measured to be 4.5 MGO
It turned out to be e. This shows that even if the organic material is heated to 120° C. and the organic material is softened, especially in the interior of the sheet, the orientation of the magnetic particles will not be disturbed because the magnetic particles are demagnetized.

One of the small sheets obtained in Example 3 was placed between the poles of a 23.5 KG electromagnet and heated at a temperature of 120° C. for 5 minutes. At this temperature the organic material in the composition melted and allowed the magnetic material to align under the magnetic field. of the sheet (B
H) Wax was 5.2 MGOe. However, heating at 120° C. for 5 minutes substantially crosslinks the sheet making it no longer possible to melt form the composition.

For comparison, another small sheet obtained in Example 3 was used and subjected to the same orientation treatment under a magnetic field as in Example 3. Within the sheet, the organic material is substantially uncrosslinked, but the magnetic particles are oriented. The sheet was heated at 120° C. for 5 minutes without being held in a mold. The sheet softened and expanded many times its original volume as a result of repulsion between adjacent magnetic particles. The sheet obtained after heating had bubbles, was brittle, and had very low magnetic performance.

The process of Comparative Example 6 was repeated with the sheet held in the mold. Heating was carried out at a temperature of 120° C. for 5 minutes. The (BH)wax of the obtained sheet was 3MGOe.

This means that although the magnetic material particles are oriented, heating a sheet of uncrosslinked organic material to a temperature at which the organic material melts will hold the magnetic particles oriented by applying a magnetic field. This indicates that the orientation of the magnetic material is lost.

1. Mix the following ingredients constituting the composition by hand to form a somewhat uniform powder mixture.

Magnetic particles: NdtaFeatBs 93.30 Equipment Materials: 4.13 parts of oligomerized and epoxidized bisphenol powder 2.29 parts of phenol formaldehyde novolac powder 0.33 parts of epoxidized phenol formaldehyde novolac powder : Copolymer powder of vinyl butyral and vinyl alcohol (trade name: Piolofor* BN 1B, WackerCh
ea+ie manufactured by GsbH) 1.26 parts Silica powder (trade name Aerosil 0X50) 0.2 parts Calcium stearate 0.17 parts Bleached Monton wax 0.17 parts 3-(3,4
-dichlorophenyl)-1,1-dimethylnylia 0.05 part The mixture was then charged into a twin roll mill at a temperature of 90°C and repeatedly passed through the mill gap to form a plastic sheet. The presence of the material helped make it into sheets.

The sheet was milled using a twin roll mill at a temperature of 80°C.
After rolling to a thickness of 7 mm, the sheet was placed in a mold and pressed at a temperature of 110°C to reduce the thickness to 0.5 mm.

The sheet was placed in a mold and rapidly heated to 140°C and then rapidly cooled to room temperature. It was found that part of the sheet could be remelted.

This indicates that even a small amount of crosslinking does not prevent the sheet from being reused. The sheet was then heated in a mold at a temperature of 170° C. for 30 minutes in order to crosslink it. (BH)a+a of the obtained sheet
x was 5.5 MGOe.

11J1 Length 11 As Examples 6 to 9, four types of compositions (the ratio of each component is shown in weight%) as shown in Table 1 were mixed by hand to form a moderately uniform mixture, and each The kneading temperature of the 9ML product, in which the mixture was separately charged into a twin roll mill and repeatedly passed through the mill gap, was 9 in Examples 6 and 7.
In Examples 8 and 9, the temperature was 100°C. Each composition was formed into a sheet and removed from the mill. next,
Each composition was pulverized into granules, put into a screw extruder, passed through a cylindrical mold, and extruded. The barrel temperature of the extrusion molding machine was 120° C., the mold temperature was 130° C., and the extrusion speed was laa/sec. A radial magnetic field of 15 KOe was applied to the special mold to orient the magnetic particles in the composition. The ambient temperature at the tip of the mold is such that the molded composition solidifies. The molded cylindrical composition had an outer diameter of 30 mm and an inner diameter of 26 mm. After the magnetic particles in the molded article were demagnetized by the method described in Example 1, they were heated at a temperature of 200° C. for 30 minutes to crosslink the resin.

Table 1 C11o, o*Feo, tzZro, ozs) 1.
: 1% magnetic particles. For comparison, three types of compositions as shown in Table 2 were used as Comparative Examples 8.9 and 10 (
The proportions of each component are shown in weight%) were mixed to form a moderately homogeneous mixture, and the mixture was separately charged into a twin roll mill at 250°C (Comparative Examples 8 and 9) or 260°C.
The mixture was kneaded at the temperature of (Comparative Example 10). The mixture was removed from the mill, barrel temperature 240°C, mold temperature 220°C, extrusion speed 0. It was extruded at 5 mg+/sec through a cylindrical mold of a screw set extruder.

A radial magnetic field of 15 KOe was applied to the mold, and the ambient temperature at the tip of the mold was such that the molded composition solidified.

The molded cylindrical composition had an outer diameter of 30 mm and an inner diameter of 26 plates.

Table 2 (A composition consisting of 95.6% magnetic particles, 4.3% nylon-12 powder, and 0.1% zinc stearate by weight cannot be mixed satisfactorily in a twin-roll mill; The magnetic performance of the cylindrical magnets made in Examples 6 to 9 and Comparative Examples 8 to 10 is shown in Table 3.

As shown in Table 3 Examples 6 to 9 and Comparative Examples 8 to 10, 95
Compositions of the invention containing greater than % by weight of magnetic particles are extrudable. In contrast, compositions consisting of conventional thermoplastic resins and more than 95% by weight of magnetic particles cannot be molded. Furthermore, the composition of the present invention has excellent magnetic performance because the magnetic particles are easily oriented during molding and exhibit a higher degree of orientation.

1JLLL Yunichiro Examples 10 to 13 have a particle size of 1 to 200 μm and a composition of Nd+a (F eo, *sc □o, os) s
o, sB3. Example 6 except that magnetic particles of .
Four types of cylindrical magnets were manufactured using the same method as in Example 9.

However, the kneading temperature was 95℃ and the extrusion speed was 2mm/s.
The difference is that it is ec.

The components of each composition in weight percent are shown in Table 4.

Table 4 Comparative Examples 11 and 12 are Examples 10 to 1, respectively.
The magnetic particles used in 3 were 90.4 and 91.7! amount%
, 9.5 and 8.2% by weight of nylon-12 powder,
Cylindrical magnets were manufactured in the same manner as in Comparative Examples 8 to 10 using two types of compositions containing 0.1 and 0.1% by weight of zinc stearate. The kneading temperature was 250°C, the barrel temperature of the extruder was 230°C, the mold temperature was 205°C, and the extrusion speed was 1 mm/sec.

(Compositions containing 92% by weight or more of magnetic particles could not be mixed satisfactorily and could not be extruded satisfactorily.) The magnetic performance of the obtained cylindrical magnets is shown in Table 5. .

Table 5 As is clear from Table 5, by using the composition of the present invention containing an organic material that is solid, meltable, moldable, and crosslinkable, the magnet has high magnetic performance even if it is isotropic. can be obtained. The poor performance of magnets made from compositions containing conventional thermoplastic polymers, namely nylon-12, is due to the high molding temperatures required to manufacture the magnets.
It is also thought that the magnetic particles were oxidized and deteriorated.

The composition used in Example 7 was kneaded in a twin roll mill in the same manner as in Examples 6 and 7, and extruded to produce a cylindrical magnet with an outer diameter of 16 mm and an inner diameter of 14 mm,
It was cut to a length of 15 mm.

As Comparative Example 13, the composition used in Comparative Example 9 was put into a twin roll mill and kneaded at a temperature of 250°C. The composition formed into a sheet was taken out from the mill, pulverized into fine particles, and put into an injection molding machine. While applying a radial magnetic field of 6KOe to the mold of an injection molding machine, the length is 15M.
, cylindrical magnets with outer and inner diameters of 16 mm and 14 mm, respectively, were injection molded.

Table 6 shows the magnetic performance of the obtained magnet.

Table 6 As is clear from Table 6, the magnet of Comparative Example 13 has properties comparable to those of an isotropic magnet. This may be due to the difficulty in applying a sufficient magnetic field to orient the particles at some times.

Implementation ■ Dogoji Main Examples 15 to 18, four types of compositions were prepared with an outer diameter of 3.
3-1 It was extruded into a cylindrical shape with an inner diameter of 32 mm (Examples 15 and 17) or 31.6 mm (Examples 16 and 18), and cut into a length of 8 mm. Example 15
and 16 are the same as used in Example 6, and the compositions of Examples 17 and 18 are the same as used in Example 10. The kneading and molding conditions in Examples 15 and 16 are the same as in Example 6, and the kneading and molding conditions in Examples 17 and 18 are the same as in Example 1.
It is 0. As comparative examples, Comparative Examples 14 to 17
The four types of compositions were prepared using the following compositions: an outer diameter of 33mm, a length of 8mm, and an inner diameter of 32+ma (Comparative Examples 14 and 16) or 31mm.
．． An attempt was made to mold the sample into a cylindrical shape of 6 mm (Comparative Examples 15 and 17). The compositions of Comparative Examples 14 and 15 were the same as those used in Comparative Example 8, and the compositions of Comparative Examples 16 and 17
The composition of is the same as that used in Comparative Example 11. The cross-wire conditions in Comparative Examples 14 and 15 are the same as those in Comparative Example 8, and the cross-wire conditions in Comparative Examples 16 and 17 are the same as in Comparative Example 11. Each composition was removed from the twin roll mill, ground and injected into an injection molding machine at a temperature of 295'C. The mold temperature was 90° C., and a radial magnetic field of 15 KOe was applied for molding.

Table 7 shows the magnetic performance of the obtained cylindrical magnet.

The compositions marked * in Table 7 did not flow satisfactorily and could not be filled into molds.

The magnetic performance of the magnet of Comparative Example 15 is comparable to that of an isotropic magnet, whereas the extruded magnet made from the composition of the present invention has sufficiently high magnetic performance.

Next ffi The composition used in Example 7 was extruded at an extrusion speed of 1 or 2.
A cylindrical magnet with radially oriented magnetic particles having an outer diameter of 16 mm and an inner diameter of 14 mm was produced by molding in the same manner as in Example 7, except that the magnetic particles were oriented in a 4III11 mm/sec manner.
Cut to 1 length. 18 magnets each with four lengths/
Manufactured in minutes.

As Comparative Example 18, the same composition as Comparative Example 13 was used as Comparative Example 1.
Injection molded under the same conditions as 3, length 4om, outer diameter 16m
A magnet with an inner diameter of 14 aa was manufactured.

The minimum molding cycle time is 20 seconds, so if molded piece by piece, only 3 pieces/min can be produced.

〔Effect of the invention〕

As described above, the present invention provides a method for manufacturing a bonded magnet using a composition consisting of a solid meltable crosslinkable organic material and magnetic material particles, and the bonded magnet is made of a thermoplastic resin such as nylon. To provide a method for manufacturing a bonded magnet that can be used up to relatively high temperatures, unlike magnets. Also,
It is characterized by the use of a composition that can reuse parts that would normally be thrown away, such as defective products during molding and unnecessary parts that inevitably come out during molding. This feature is not present in conventional magnets made of compositions using resins that undergo crosslinking reactions. Furthermore, although it is common to apply a magnetic field during the cross-linking reaction to maintain the orientation of the magnetic particles, the present invention eliminates the need for this and improves productivity compared to other known methods described herein. It has the characteristics of being considerably superior to The present invention further provides a highly flexible manufacturing method that allows magnets of simple or complex shapes to be manufactured. For example, fairly long bonded magnets (e.g. long cylindrical magnets) can be manufactured by methods such as extrusion.

The magnets produced according to the invention are light. For example, it is only about two-thirds the weight of a metal magnet of the same size. Also,
Magnets produced according to the present invention are much more brittle than ceramic magnets.

Magnets produced according to the present invention can be applied to many applications. Examples include motors, televisions, printers and suction devices (eg suction devices at doors).

that's all Applicant Imperial Chemical Industries P.E. Lucy

Claims (1)

[Scope of Claims] 1. A method for producing a molded article having magnetic performance using a composition containing as constituent elements an organic material that can be solid melt-molded and cross-linked, and magnetic material particles. (1) molding the composition in a mold at a temperature such that the organic material is in a fluid state; (2) cooling the molded product to a temperature at which the organic material solidifies;
Furthermore, (3) a method for producing a magnetic molded article, which comprises a step of crosslinking an organic material in the molding composition as a component in order to obtain a crosslinked material. 2. A method for producing an anisotropic magnet, including: (1) molding the composition in a mold at a temperature such that the organic material is in a fluid state; (2) when the organic material is in a fluid state; applying a magnetic field to the composition; (3) cooling the molded article to a temperature at which the organic material solidifies;
The method for producing a magnetic molded article according to claim 1, further comprising (4) a step of crosslinking an organic material in the molding composition as a component in order to obtain a crosslinked material. 3. The method for producing a magnetic molded article according to claim 1 or 2, wherein the crosslinking of the organic material in the molding composition is carried out when the organic material is in a solid state. 4. The method for producing a magnetic molded article according to any one of claims 1 to 3, characterized in that the magnetic particles are demagnetized before crosslinking the organic material. 5. The method for producing a magnetic molded article according to claim 4, wherein the shape of the composition is maintained during crosslinking of the organic material. 6. The method for producing a magnetic molded article according to claim 5, wherein the magnetic material particles are re-magnetized after crosslinking the organic material. 7. The method for producing a magnetic molded article according to any one of claims 1 to 6, wherein the melting point of the organic material in the composition is 25°C or higher. 8. The method for producing a magnetic molded article according to any one of claims 1 to 7, wherein the organic material in the composition contains a monomer material as a constituent element. 9. The method for producing a magnetic molded article according to any one of claims 1 to 7, wherein the organic material in the composition contains a polymer material as a constituent element. 10. The method for producing a magnetic molded article according to claim 8, wherein the monomer material contains a substance having one or more ethylenically unsaturated groups. 11. The method for producing a magnetic molded article according to claim 10, wherein the monomer material is an adduct of 4,4'-diphenylmethane diisocyanate and hydroxymethacrylate. 12. The method for producing a magnetic molded article according to claim 9, wherein the polymer material is an epoxy resin. 13. The method for producing a magnetic molded article according to claim 12, wherein the epoxy resin contains epoxidized bisphenol A, epoxidized phenol formaldehyde novolak, and phenol formaldehyde novolak as a hardening agent. 14. The method for producing a magnetic molded article according to any one of claims 1 to 13, wherein the composition contains as a constituent an additive that causes or promotes crosslinking. 15. The production of a magnetic molded product according to claim 14, wherein the organic material contains as constituent elements a substance having one or more ethylenically unsaturated groups and an additive that is a radical initiator. Method. 16. The method for producing a magnetic molded article according to any one of claims 1 to 15, wherein the particle size of the magnetic material is in the range of 0.5 to 200 μm. 17. The method for producing a magnetic molded article according to any one of claims 1 to 16, wherein the magnetic material particles contain an intermetallic compound of at least one rare earth element and at least one transition metal as constituent elements. . 18. The method for producing a magnetic molded article according to claim 17, wherein the transition metal contains Co as a constituent element or is Co. 19. The magnetic material is approximately RCo_5 or R_2Co
_1_7 (R is at least one type of rare earth element)
Claim 17 or 1, characterized in that it has a compositional formula of
8. The method for producing a magnetic molded article according to 8. 20. The method for producing a magnetic molded article according to any one of claims 17 to 19, wherein the rare earth element contains Sm as a constituent element or is Sm. 21. Claim 17, wherein the magnetic material particles contain an intermetallic compound consisting of Nd-Fe-B as a constituent element.
A method for producing a magnetic molded article as described in . 22. A method for producing a magnetic molded article according to any one of claims 1 to 21, characterized in that the composition contains at least 80% by weight of magnetic material particles. 23. A method for producing a magnetic molded article according to any one of claims 1 to 22, characterized in that the composition contains at least 5% by weight of organic material. 24. The method for producing a magnetic molded article according to any one of claims 1 to 23, characterized in that the composition contains 0.01 to 2% by weight of an additive. 25. Magnetic molded article according to any one of claims 1 to 24, characterized in that the composition contains a polymeric material that can be dissolved or dispersed in the organic material when it is in a liquid state. manufacturing method. 26. Process for producing magnetic moldings according to claim 25, characterized in that the composition contains from 0.5 to 5% by weight of polymeric material. 27. The method for producing a magnetic molded article according to any one of claims 1 to 26, wherein the composition is kneaded under conditions of high shear force. 28. Claims 1 to 2, characterized in that the composition is molded by extrusion molding, injection molding or compression molding.
6. The method for producing a magnetic molded article according to any one of 6. 29. The method for producing a magnetic molded article according to any one of claims 3 to 28, characterized in that the organic material is crosslinked in a solid state by irradiating the composition with electron beams or gamma rays. 30. The magnetic molded article according to any one of claims 5 to 29, characterized in that when the organic material is in a solid state, the outer surface of the molding composition is first crosslinked to maintain the shape of the composition. Production method. 31. A bonded magnet manufactured by the manufacturing method according to any one of claims 1 to 30. 32. A composition suitable for use in the production of molded articles having magnetic properties, which comprises the following components: (1) a solid melt-formable and crosslinkable organic material; 1.) magnetic material particles; and (3) a polymeric material that can be dissolved or dispersed in the organic material when the organic material is in a liquid state. 33. The composition according to claim 32, characterized in that the organic material has a melting point of 25°C or higher. 34. The composition according to claim 32 or 33, characterized in that the organic material comprises a monomeric material as a constituent. 35. Composition according to claim 32 or 33, characterized in that the organic material comprises a polymeric material as a constituent. 36. The composition of claim 34, wherein the monomer material contains a material with one or more ethylenically unsaturated groups. 37. A composition according to claim 36, characterized in that the monomer material is an adduct of 4,4'-diphenylmethane diisocyanate and hydroxymethacrylate. 38. A composition according to claim 35, characterized in that the polymeric material is an epoxy resin. 39. The composition according to claim 38, wherein the epoxy resin comprises as constituents epoxidized bisphenol A, epoxidized phenol formaldehyde novolac and phenol formaldehyde novolac as a hardening agent. 40. The composition according to any one of claims 32 to 39, characterized in that it contains as a constituent an additive that causes or promotes crosslinking. 41. The composition according to claim 40, characterized in that the organic material contains as constituents a substance having one or more ethylenically unsaturated groups and an additive which is a radical initiator. 42. The composition according to any one of claims 32 to 41, characterized in that the particle size of the magnetic material is in the range of 0.5 to 200 μm. 43. The composition according to any one of claims 32 to 42, wherein the magnetic material particles contain an intermetallic compound of at least one kind of rare earth element and at least one kind of transition metal. 44. The composition according to claim 43, wherein the transition metal contains Co as a constituent or is Co. 45, magnetic material is approximately RCo_5 or R_2Co
_1_7 (R is at least one type of rare earth element)
45. The composition according to claim 44, having the formula: 46. The composition according to any one of claims 43 to 45, wherein the rare earth element contains Sm as a constituent element or is Sm. 47. Claim 43, wherein the magnetic material particles contain an intermetallic compound consisting of Nd-Fe-B as a constituent element.
The composition described in . 48. A composition according to any of claims 32 to 47, characterized in that it contains at least 80% by weight of particles of magnetic material. 49. Composition according to any of claims 32 to 48, characterized in that it contains at least 5% by weight of organic material. 50. Composition according to any of claims 40 to 48, characterized in that it contains from 0.01 to 2% by weight of additives. 51. A composition according to any of claims 32 to 50, characterized in that it contains a polymeric material that can be dissolved or dispersed in the organic material when it is in the liquid state. 52. A composition according to claim 51, characterized in that it contains from 0.5 to 5% by weight of polymeric material.