JPS61263741A - Sheet-shaped composite magnetic material - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a resin-bonded magnet that is widely used in the mechatronics field as a member of pulse motors, servo motors, actuators, etc. The present invention relates to the structure of a sheet-like composite magnetic material before it becomes a molded magnet.

2. Description of the Related Art Conventionally, resin-bonded magnets commonly used are composed of ferromagnetic particles and a resin composition. The ferromagnetic particles have the general formula MO・nFe203 (where M is B a +
Ferrite magnet particles known as one or more selected from the group S r * P b, where n is a number from 4.5 to 6.2), general formula RCo5 or R2TM17 (however, in the formula R
is a rare earth element such as Sm, Pr, or Ce, and TM is a transition metal element mainly composed of CO).The magnetic anisotropy constant is approximately 108 to 108 e
It is a ferromagnetic material that has a large value of r g/cd, and the size of these particles is adjusted to about a single magnetic domain determined from the magnetic anisotropy constant specific to the ferromagnetic material, that is, fine particles of about 1 to 5 μm. It is what was done. Furthermore, the ferromagnetic particles generally account for 60 to 70 VO2% of the composite magnetic material. The reason for this is that the residual magnetic flux density Br of the resin-bonded magnet is
is proportional to 4πσ5xRsxd (where σS is the saturation magnetization Rs of the ferromagnetic material, and d is the volume fraction of the ferromagnetic material), and in order to ensure magnetic performance, it is based on magnetic anisotropy. This is because it is necessary to create a composite magnetic material in which a large amount of ferromagnetic material is added within a range that does not significantly affect the degree of orientation.

Problems to be Solved by the Invention However, the fine particle ferromagnetic material described above has a configuration that has a favorable effect on the physical properties of resin molded products, which are one aspect of resin bonded magnets, especially regarding dimensional accuracy and mechanical strength. It cannot be called an ingredient. This phenomenon is explained by Griffin
It is appropriate to apply the theory of th, and in particular, the decrease in tensile strength and transverse rupture strength is remarkable.

This is rarely a serious drawback in applications where the functions of both the magnet and the structural material are required, such as resin-bonded magnets used as components in motors, etc.
do not have. Therefore, as in Japanese Patent Application Laid-Open No. 54-57552,
By using an inorganic non-magnetic filler in a composite magnetic material consisting of ferromagnetic particles and a resin composition, a constant shrinkage behavior is always produced regardless of the content of ferromagnetic particles, thereby ensuring dimensional density. , Japanese Patent Publication No. 59-23446, many devices and inventions have been made, such as a method to ensure the mechanical strength of a resin-bonded magnet by overlapping and laminating a resin-bonded magnet and a reinforcing fiber sheet impregnated with the resin. has been accomplished.

As mentioned above, the method of securing the physical properties of a resin-bonded magnet as a resin molded product by using an inorganic non-magnetic filler in combination with the former method inevitably reduces the magnetic performance, which is an important function. It is not preferable as a member. On the other hand, the latter method of securing the physical properties of a resin-bonded magnet as a resin molded product by superimposing and laminating a resin-bonded magnet and a fiber-reinforced sheet impregnated with the resin or a resin with excellent affinity for the resin is Combined magnet part and PRCM (F1ber Re1nt'or
ced C.

5-pite materials) are integrally laminated, so when the whole is considered as one member, the magnetic energy per unit volume decreases. This means that improvements must be made for use in products that require both magnetic properties and functionality as a structural material, such as resin-bonded magnets used as components in motors, etc. .

Based on the above background, the present invention aims to improve the mechanical strength of the resin-bonded magnet while ensuring the magnetic performance of the resin-bonded magnet using fibers. That is, the present invention aims to provide a resin-bonded magnet that has both magnetic performance and a function as a structural member and is suitable for members such as motors.

Means for Solving the Problems In the present invention, a glass nonwoven fabric having a glass density of 30 g/d or less is interposed on at least a portion of the surface of a sheet made of ferromagnetic particles and a resin composition. Further, if necessary, a polymer layer of an arbitrary thickness, which is mainly composed of a polymer having a molecular weight of 103 or more and having an alcoholic hydroxyl group in the molecule, is formed on a part of the surface of the sheet.

The constituent components of the present invention will be explained in more detail below.

The glass nonwoven fabric referred to in the present invention is, for example, one in which glass filaments with a diameter of about 10 μm are sprayed onto a surface in an unspecified direction, and the filaments are fixed with pine dust such as epoxy resin. Therefore, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-
methoxy-ethoxysilane), γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, methacrylate chromic chloride, N-β
A silane coupling agent having a functional group suitable for the resin composition constituting the composite magnetic material, such as (aminoethyl)γ-aminoprobyltrimentoxysilane, may be added as a constituent component. In short, it is desirable that the glass density of the glass nonwoven fabric made of such components is 30 g/d or less, and more preferably 20 g/d or less.

Next, the ferromagnetic particles referred to in the present invention include the already described ferrite magnet particles and rare earth cobalt particles, as well as M n -A Q -C magnet particles with a large magnetic anisotropy constant, Nd-F
-B refers to magnetic particles, etc.

Furthermore, the resin composition referred to in the present invention may include thermoplastics such as polyamide-12 copolymers, homopolymers, elastomers, etc., but preferably epoxy resins,
These are thermopolymerizable resins such as unsaturated polyester resins.

In addition, the polymers having a molecular weight of 104 or more and having an alcoholic hydroxyl group in the molecule that can be used in combination in the present invention are the following (1)
), which has the ability to form a surface film, such as polyether or polyether ester having a structure represented by the formula (2).

-C-0)m...■
However, in the above formula, n and m are integers, R1 is an aliphatic residue, R2 is hydrogen or an alkyl group, and R3 is an aliphatic, aromatic, or alicyclic residue. Incidentally, a substance capable of cross-linking with the alcoholic hydroxyl group contained in the molecule may be used as a constituent within a range that does not impair such surface film-forming ability. For example, an isocyanate regenerated product in which an active hydrogen compound that exhibits a nucleophilic reaction is added to the carbon atom of a terminal isocyanate group is used.

There are press methods, casting methods, calendering methods, extruding methods, etc. to produce sheet-like composite materials using the above-mentioned components, and these methods are not particularly limited, but continuous production is possible. From the viewpoint of stability and thickness accuracy, it is preferable to use the calendering method or the extruding method as the basic method.

Furthermore, the step of combining glass nonwoven fabric, which is the gist of the present invention, may be a step of forming a sheet-like composite magnetic material into a sheet, or a step before forming it into a desired shape, or even a step of forming a resin-bonded magnet. There is no problem at any stage of manufacturing.

It goes without saying that the same applies to polymers having a surface film-forming ability that can be used as appropriate and necessary in the present invention.

The sheet-like composite magnetic material according to the present invention made of the above-mentioned components can be made into a resin-bonded magnet imparted with magnetic anisotropy by ordinary magnetic field forming means. The molding means is ultimately selected by selecting a resin composition that meets the reliability and quality of the resin-bonded magnet used, and by taking into consideration economic efficiency.

action Hereinafter, the operation of the present invention will be explained in detail.

The gist of the present invention is to provide a glass nonwoven fabric having a glass density of 30 g/- or less on at least a portion of the surface of a sheet-like composite magnetic material. The reason for focusing on the glass density of the glass nonwoven fabric here is that if it is defined by thickness, the range in which the effects of the present invention can be obtained becomes unclear. In addition, it goes without saying that the composite portion of the glass nonwoven fabric is a resin-bonded magnet that also functions as a structural member, and is a portion where stress is likely to concentrate, but preferably both surfaces of the sheet-like composite magnetic material are composited. It can be easily inferred that it has a sandwich structure.

As mentioned above (even if an anisotropic resin-bonded magnet is manufactured from a sheet-like composite magnetic material made of a sandwich composite of glass non-woven fabrics with a glass density of 30 g/- or less, the same magnetic field as when the glass non-woven fabric is not used) In addition, the mechanical strength, such as tensile strength and transverse rupture strength, can be maintained at
It is also possible to secure a value as high as 0 to 30%.

Example (Example 1) The present invention will be explained in more detail with reference to Examples below.

A solid unsaturated polyester alkyd having an acid value of 18 was obtained using terephthalic acid and fumaric acid as raw materials according to a conventional method. The melting point of the obtained unsaturated polyester alkyd was 91°C,
This was dissolved in diallyl phthalate as a copolymerizable monomer at room temperature to obtain a 30% solution of diallyl phthalate. Furthermore, 1% dicumyl peroxide was added as a polymerization initiator.
This was used as a resin matrix.

Nine parts of 5rO-FeI2018 magnet particles treated with 1% vinyltriethoxysilane were added to 10 parts by weight of the above resin matrix.
After adding 0M parts and kneading in a 35III11 co-rotating twin-shaft extruder according to a conventional method, a sheet-like composite magnetic material having a thickness of 2m was obtained.

The above composite magnetic material was heated at 160℃×6 in a magnetic field of 10KOe.
Sheet molding was performed as it was under the condition of 0 sec, and sheet molding was performed under the same conditions on the sheet-shaped composite magnetic material in which a glass nonwoven fabric was sandwiched on both surfaces of the sheet-shaped composite magnetic material to improve the glass density. Table 1 shows the mechanical properties such as transverse rupture strength and tensile strength, and magnetic properties of these resin-bonded magnets.

Compared to the conventional example that is not reinforced with a nonwoven fabric, the example of the present invention has a tensile strength of approximately 1.35 to 1.70 times and a transverse rupture strength of 1.3 times.
Although the surface magnetic flux density is improved by 3 to 1.90 times, almost the same amount of surface magnetic flux density can be obtained. However, Comparative Example 1,
When the glass density becomes high as in 2, the surface magnetic flux density decreases because the resin-bonded magnet portion and the surface layer are separated.

In Comparative Examples 1 and 2, a glass nonwoven fabric prepreg was used by impregnating a glass nonwoven fabric with a resin composition that was the same as or had good affinity with the resin matrix used in the resin-bonded magnet. In this case, mechanical strength such as tensile strength or transverse rupture strength is improved compared to the example of the present invention. However, the surface magnetic flux density decreases because the surface layer forms voids.

As described above, the present invention can improve the performance of a resin bonded magnet as a structural member by improving its mechanical strength while maintaining its magnetic performance.

(Example 2) The 2m thick sheet-like composite magnetic material obtained in Example 1 was heated for 5ms.
A slit is made in the width, and a molecular weight of 25,000~ is applied to the slit surface.
15-30μm by 30,000 polyether resin
A thick fusion layer was formed. Furthermore, the same procedure was carried out using a mixture of a regenerated isocyanate represented by the following formula (3) capable of cross-linking with the alcoholic hydroxyl group of the polythiethyl resin at a ratio of OH/NCO of 0,3,0,5.

The resin composition layer newly added to the above-mentioned sheet-like composite magnetic material did not affect the flexibility of the sheet, but rather improved the handling properties by increasing the toughness.

The above-mentioned sheet-like composite magnetic material was wound around a mandrel having a diameter of 51111 mm and heated at 160° C. for 5 m1n to obtain a cylindrical resin-bonded magnet with an inner diameter of 5III11 and an outer diameter of 9III1. The rupture strength of this resin-bonded magnet was significantly improved as shown in Table 2, compared to the magnet without the resin composition layer according to the present invention.

However, in the table, Conventional Example 2 is simply a sheet-like composite material tightly wound around a mandrel, and Conventional Example 3 is a sheet-like composite material that is heated and compressed in a mold.

As described above, when a film is formed using the resin composition of the present invention, a resin-bonded magnet having high mechanical strength can be obtained by simply winding the film tightly around a mandrel and heating it.

Effects of the Invention As described above, the present invention is capable of improving the mechanical strength of a resin-bonded magnet while maintaining its magnetic performance, thereby improving its function as a structural member. Therefore, it can be widely applied to fields such as parts such as motors that require the function of a structural machine as well as the function of a magnet.

Claims (2)

[Claims] (1) A sheet-like composite magnetic material in which a glass nonwoven fabric having a glass density of 30 g/m^2 or less is interposed on at least a portion of the surface of a sheet made of ferromagnetic particles and a resin composition. (2) The sheet-like composite magnetic material according to claim 1, wherein at least a portion of the surface of the sheet is provided with a polymer layer mainly composed of a polymer having a molecular weight of 10^4 or more and having an alcoholic hydroxyl group.