JPS62199002A - Composition for synthetic resinous magnet and synthetic resinous magnet and magnet roll made of the same - Google Patents

Abstract

PURPOSE:To easily manufacture a synthetic resinous magnet and a magnet roll with high accuracy, by making magneto plumbite-type ferrite powder, substance specific in a chemical formula, and a kind selected from specific resin, contained in a composition material for resinous magnet, so that maximum energy of the composition becomes large. CONSTITUTION:Magneto plumbite-type ferrite powder, substance shown in a formula, where R1-R3 are alkyl groups or alkoxy ones having carbons in numbers 3-20, and a kind of polyvinyl chloride resin, vinyl chloride resin, vinyl copolymer resin, vinyl acetate resin, polyethylene chlorinate resin, and ethylene-vinyl acetate resin, are made to be contained in a composition material for synthetic resinous magnet. Thus, the synthetic resinous magnet, superior surface magnet, and magnet roll high-accurate in dimension can be obtained from the composition material for superior synthetic resin magnet is inexpensive and large in maximum energy product.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to resin magnets, so-called bonded magnets, and its purpose is to provide resin magnet compositions that have excellent magnetic properties, more specifically, have a large maximum energy product and are inexpensive. , to provide a synthetic resin magnet and a magnet roll made of the same.
The resin magnet composition according to the present invention is formed by, for example, a magnetic field oriented extrusion method, and can be effectively applied to functional fields such as magnets for attraction such as Gaskent, magnet rolls for magnetic brushes in dry copying, or magnet rolls for cleaning. It is particularly useful as a magnetic roll for dry copying magnetic brushes.

"Prior art and its problems" Resin magnets have come to be used in various fields because they can produce molded objects with high dimensional accuracy, are strong in impact strength, and can also be made into flexible magnets. It's here. However, there are major limitations due to the inferior magnetic properties, such as the maximum energy product, compared to sintered magnets, and the amount of resin magnets used is still small.The reason why the maximum energy product of resin magnets is inferior to that of sintered magnets One reason is that the ratio of the magnetic material to the apparent volume of the magnet is lower than that of a sintered magnet. One of the other reasons is that the orientation of the magnetic powder in the resin is low. Generally, magnetic powder has magnetic anisotropy derived from its crystal structure, and in order to increase the maximum energy product of a resin magnet, it is necessary to align the directions of the magnetic anisotropy. It is particularly effective to enhance the orientation of the powder.

Orientation of magnetic powder can be achieved mechanically or magnetically, with the latter generally preferred. However, since the orientation of the magnetic powder is achieved by rotation of the magnetic powder particles in the resin, the viscosity of the resin, that is, the viscosity during magnetic field orientation molding processing is important. The lower the viscosity of the resin, the higher the orientation of the magnetic powder by the magnetic field.

As described above, in order to increase the value of the maximum energy product of a magnet, two points are important: increasing the volume ratio of the magnetic powder and increasing the orientation of the magnetic powder. However, as the volume ratio of the magnetic powder increases, the viscosity of the resin magnet composition increases, and the degree of orientation of the magnetic powder not only decreases, but also becomes impossible to mold. be.

It is known that surface treatment of magnetic powder with a silane coupling agent or a titanate coupling agent is used.Resin magnets using surface-treated magnetic powder only have an increased volume ratio and orientation of the magnetic powder. In general, mechanical strength such as impact strength is also improved.

Japanese Unexamined Patent Publication No. 59-. No. 170130 and JP-A-59-170
No. 131 proposes coating the surface of inorganic powder such as magnetic powder with a phosphorus compound.

However, the maximum energy product of the resin magnet obtained is 1.5
1 = 1.83 (MGOe), which is still not sufficient.The technology disclosed in JP-A-60-240105 is a surface treatment for the purpose of preventing oxidation of rare earth-iron group-boron alloy magnetic powder. As the agent, a phosphorus compound having a po bond in the molecule is used.

On the other hand, completely independent of the above technology, the present inventors also filed a patent application filed in 1983.
-54808, magnetoplumbite type ferrite powder and a substance (hereinafter referred to as ,
We proposed a synthetic resin magnet composition whose basic components are a phosphorus-based compound) and a synthetic resin.

"Means for Solving the Problems" In view of the above circumstances, the present invention enables high filling of magnetic powder,
In order to produce resin magnets with a high degree of orientation of magnetic particles and a large maximum energy product at low cost and with good moldability, as a result of intensive research, we developed magnetoplumbite type ferrite powder, phosphorus compounds, and polyvinyl chloride resin. , a vinyl chloride-vinyl acetate copolymer resin, a vinyl acetate resin, a chlorinated polyethylene resin, and an ethylene-vinyl acetate resin. Headline,
The present invention has been completed.

That is, the first aspect of the present invention is a magnetoplumbite type ferrite powder and a powder represented by the formula % (wherein R, R and R3 represent an alkyl group or an alkoxy group having 3 to 20 carbon atoms). and at least one of polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl acetate resin, chlorinated polyethylene resin, and ethylene-vinyl acetate resin. The resin magnet composition
The second aspect of the present invention is a magnetoplumbite type ferrite powder and a formula OH011 (wherein RR and R3 are 1 with a carbon number of 3 to 20).
2 alkyl group or alkoxy group) and at least one of polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl acetate resin, chlorinated polyethylene resin, and ethylene-vinyl acetate resin. The third aspect of the present invention is an anisotropic resin magnet with excellent magnetic properties formed by molding a resin magnet composition containing a magnetoplumbite type ferrite powder by a magnetic field orientation extrusion method.
Formula 0 Formula% (In the formula, RR and R3 are 1 with 3 to 20 carbon atoms.
2 alkyl group or alkoxy group) and at least one of polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl acetate resin, chlorinated polyethylene resin, and ethylene-vinyl acetate resin. Each content is a magnet roll made of an anisotropic resin magnet obtained by molding a resin magnet composition containing the following by a magnetic field orientation extrusion method.

In the present invention, it is desirable that the magnetoplumbite type ferrite ferrite has an average grain size of 0.5 to 5.0 μm and a compressed density of 3.20 g/cc or more. It becomes a single magnetic domain with a size of approximately 0.1 to several μm. In other words, it is possible to have a single magnetically easy magnetization direction. Compared to multi-domain particles (particles in which one particle has two or more easy magnetization directions), such single-domain particles have
It is suitable for the present invention because it has excellent orientation due to a magnetic field.

When the particle size increases beyond 5.0 μm, the number of multi-domain particles increases.

The higher the filling rate of the ferrite powder, the higher the magnetic properties of the resulting resin magnet. The filling rate of the ferrite powder is determined in consideration of both the desired magnetic properties and processability. In the above particle size range, the larger the particle size of the acid ferrite powder, the higher the filling is possible as a general tendency, but if it exceeds 75 volume percent, moldability is impaired.

On the other hand, the smaller the particle size of acid ferrite powder, the more
The average particle size of the acid ferrite powder is from 0.85 to 5.0 μm, more preferably from 0.8 to 2. .5 μm is chosen.

Here, compressed density means 1000 kg/1000 kg of ferrite powder.
It refers to the apparent density of ferrite powder when compressed at a pressure of aj. Since a high compressed density means a high volumetric filling rate of the ferrite powder under a constant pressure, it is thought that high filling in the resin binder becomes possible.

Moreover, in the case of the same filling amount, it is considered that the rotation of the filled ferrite powder becomes smooth and the orientation (degree of orientation) becomes high as a result. rk compressed density is 3.20 g
/cc or more, preferably 3.25 g /cc or more, more preferably 3.30 g /ce or more.

Among many magnetoplumbite type ferrite powders,
Anisotropic barium ferrite powder and/or anisotropic strontium ferrite powder are particularly suitable because they have excellent magnetic properties and are inexpensive.

The phosphorus compound used in the present invention has moderate compatibility (not particularly good compatibility, but particularly poor compatibility) with polyvinyl chloride resin or a synthetic resin with similar compatibility with polyvinyl chloride resin. The phosphorus-based compound is particularly selected from among the types of ferrite powder as a substance that has a The primary objective is to control the compatibility of the composition.If the interface has particularly good compatibility, the mechanical strength, such as bending strength and impact strength, of the molded product of the composition will be dramatically improved. However, the apparent viscosity increases during molding of the molded product,
As a result of the magnetic field preventing the rotation of the ferrite powder,
The degree of orientation becomes low. Furthermore, the molding temperature also needs to be high. On the other hand, if the compatibility at the interface is particularly poor, the mechanical strength of the molded product of the composition will be extremely reduced, making it unsuitable.

When molding is performed by an extrusion method, the viscosity of the molten composition during magnetic field orientation during molding is higher than in the injection method. For the above reasons, in the formula of the phosphorus compound, the number of carbon atoms in R, R, and R must be at least in the range of 3 to 20. The carbon number range is more preferably 8 to 20.

It is appropriate that the phosphorus compound is added in an amount of 0.1 to 2.1 parts by weight per 100 parts by weight of the ferrite powder. v
Although the method of adding the phosphorus compound is not particularly limited, it is a preferred embodiment to treat the surface of the ferrite powder with the phosphorus compound in advance.

The surface area of ferrite powder can be expressed as the surface area per unit weight, the so-called specific surface area (usually measured by the BET method. The unit is rrr/g). In the present invention, the amount of the phosphorus compound added is 5 x 10-4 to 1 x 100-2 (per unit surface area of ferrite powder)
/rrr) is appropriate. More preferably, 1 x 1
The surface of the ferrite powder is treated with 0-3 to 8 x 100-3 (/n) of the substance in advance.

The first feature of the present invention is that at least one of polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl acetate resin, chlorinated polyethylene resin, and ethylene-vinyl acetate resin is used as one component of the composition. It is to include. There is no problem in mixing two or more types of resins, and the types and amounts of the resins to be mixed are determined depending on the desired mechanical properties of the molded article. In the case of obtaining a hard molded article, for example, it is achieved by adding a chlorinated polyethylene resin or an ethylene-vinyl acetate resin to a base of a polyvinyl chloride resin or a vinyl chloride-vinyl acetate copolymer resin. There is no problem with adding plasticizers such as dioctyl phthalate.

In the present invention, it is a preferred embodiment to add stabilizers and lubricants for processing and shaping the composition. Tribasic sulfuric acid is known as a stabilizer for vinyl chloride resins, and it was confirmed that it is effective as a stabilizer in the composition of the present invention and does not impair the magnetic properties of the molded article.

The second feature of the present invention is that Me-R (represents an aliphatic carboxylic acid metal salt having 8 or more carbon atoms; Me is lead, tin, zinc,
Substances represented by metals such as strontium, calcium, barium, and aluminum are recognized not only as stabilizers and/or lubricants, but also as effective in improving the degree of orientation of ferrite powder. Among the substances represented by Me-R, a combination of a fatty acid having 12 to 20 carbon atoms and a metal such as lead, calcium, or barium is more preferable.

In particular, calcium stearate is convenient because it is inexpensive and stably available, and is highly effective in improving the degree of orientation of ferrite powder, for example, when the ferrite powder is highly filled.

A third feature of the present invention is that the resin magnet composition according to the present invention is particularly suitable for magnetic field oriented extrusion molding. The magnetically oriented extrusion molding method not only has good dimensional accuracy, but also has uniform magnetic properties in the longitudinal direction and can produce molded bodies of any length with high productivity, so it is a particularly preferred molding method. It is one of the. The magnetically oriented extrusion molding method allows molding with a complex cross-sectional shape, and can easily produce a molded product with a magnetically complex shape such as radial orientation or polar anisotropic orientation.

Therefore, the fourth feature of the present invention is that the anisotropic resin magnet according to the present invention is particularly suitable as a permanent magnet of a magnetic brush magnet roll for dry copying. The resin magnet of the present invention is particularly suitable because the stored permanent magnet is required to have a long shape and a uniform and high surface magnetic field in the longitudinal direction, and also requires high dimensional accuracy in the radial direction. .

The composition for a resin magnet according to the present invention has a diameter of 500 oersted or more, preferably 10,000 oersted, more preferably 2000 oersted or more.
By melt-extruding the composition through a die while applying a magnetic field greater than or equal to Manchurusted, it is possible to develop its characteristics. Furthermore, the resin magnet according to the present invention has a feature that it does not necessarily require the steps of demagnetization and magnetization after the molding.

"Examples" The present invention will be described in detail below based on Examples and Comparative Examples, but the present invention is not limited by these in any way.

Examples 1 to 4, Comparative Examples 1 to 3 Strontium tumalite powder, phosphorus compound I<1 to type of substance 〇-P-R2, phosphorus compound H species 11B O-P -OR, synthesis The resin and other additives were weighed in the proportions shown in Table 1 to give a total weight of 50 kg, and mixed in a Benschel mixer with a capacity of 100 A.
Mixed for 5 minutes.

Thereafter, each of the seven formulations was extruded into strands using a 65 mφ twin-screw mixing extruder at a temperature in the range of 130°C to 160°C, and pelletized using a real cut method.

The pellets were then extruded in a homemade goo while applying a magnetic field of 15,000 oersteds. The extrusion temperature was controlled within the range of 145°C to 165°C.

The cross section of the obtained magnetic field oriented extrusion molded product is lQmXlofi
As shown in Table 2, the magnetic properties of the Examples were better than those of the Comparative Examples.

Table 2 "Operations and Effects" As mentioned above, according to the present invention, there is provided an excellent composition for a synthetic resin magnet that is inexpensive and has a large maximum energy product, a synthetic resin magnet, and has a high surface magnetic field and high dimensional accuracy. You can get a magnetic roll.

Procedural amendment 1, Indication of case 1985 Patent Application No. 43374 2, Title of invention Composition for synthetic resin magnets, synthetic resin magnets made of the same and magnet roll 3, Person making the amendment Relationship with the case: Patent applicant Address: 3-2-4 Nakanoshima, Kita-ku, Osaka Name (094)
) Kanebuchi Chemical Industry Co., Ltd. Representative Representative Director Niino
Makoto 4, agent address: 3-2-4-5 Nishitenma, Kita-ku, Osaka City, subject of amendment ■Specification, page 15, line 4, ``Improved molding...''
Correct the statement `` to ``molding process...1''.

■ Same (, page 15, line 8 to question line 9, “...R,
The number of carbon atoms in R and R is...” is replaced by “...R1,
The number of carbon atoms in R2 and R3 is corrected to ``...''.

■Similarly, on page 15, line 13, it says “0.1~
2.1 parts by weight...'' is replaced by 0.1 parts by weight.
〜2.01 parts...''

that's all

Claims (1)

[Claims] 1. Magnetoplumbite type ferrite powder, formula ▲ includes mathematical formula, chemical formula, table, etc. ▼ and/or ▲ mathematical formula,
There are chemical formulas, tables, etc. ▼ (In the formula, R_1, R_2 and R_3 represent an alkyl group or an alkoxy group having 3 to 20 carbon atoms), polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer A composition for a magnetically excellent resin magnet, comprising at least one of a composite resin, a vinyl acetate resin, a chlorinated polyethylene resin, and an ethylene-vinyl acetate resin. 2. The magnetoplumbite type ferrite powder has an average particle size of 0.5 to 5.0 μm and a compressed density of 3.20 g/cc.
The composition for a resin magnet according to claim 1, wherein the composition is 50 to 75% by volume. 3.For 100 parts by weight of magnetoplumbite type ferrite powder, there are formulas ▲mathematical formulas, chemical formulas, tables, etc.▼ and/or ▲mathematical formulas,
There are chemical formulas, tables, etc. ▼ (In the formula, R_1, R_2 and R_3 represent an alkyl group or an alkoxy group having 3 to 20 carbon atoms). A composition for a resin magnet according to claim 1 or 2. 4. The resin magnet composition according to any one of claims 1 to 3, which contains a metal salt of aliphatic carboxylic acid having 8 or more carbon atoms. 5. Magnetoplumbite type ferrite powder, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and/or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1R_2 and R_3 are alkyl groups with 3 to 20 carbon atoms or an alkoxy group);
A resin magnet composition containing at least one of polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl acetate resin, chlorinated polyethylene resin, and ethylene-vinyl acetate resin is molded by magnetic field orientation extrusion method. Anisotropic resin magnet with excellent magnetic properties. 6. The magnetoplumbite type ferrite powder has an average particle size of 0.5 to 5.0 μm and a compressed density of 3.20 g/cc.
6. The anisotropic resin magnet according to claim 5, wherein the above amount is 50 to 75% by volume. 7.For 100 parts by weight of magnetoplumbite type ferrite powder, there are formulas ▲mathematical formulas, chemical formulas, tables, etc.▼ and/or ▲mathematical formulas,
There are chemical formulas, tables, etc. ▼ (In the formula, R_1, R_2 and R_3 represent an alkyl group or an alkoxy group having 3 to 20 carbon atoms). An anisotropic resin magnet according to claim 5 or 6. 8. The anisotropic resin magnet according to any one of claims 5 to 7, which contains a metal salt of aliphatic carboxylic acid having 8 or more carbon atoms. 9. Magnetoplumbite type ferrite powder and formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and/or ▲ mathematical formulas,
There are chemical formulas, tables, etc. ▼ (In the formula, R_1, R_2 and R_3 represent an alkyl group or an alkoxy group having 3 to 20 carbon atoms), polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer An anisotropic material with excellent magnetic properties obtained by molding a resin magnet composition containing at least one of a composite resin, a vinyl acetate resin, a chlorinated polyethylene resin, and an ethylene-vinyl acetate resin by a magnetic field orientation extrusion method A magnetic roll made of synthetic resin magnets. 10. The magnetoplumbite type ferrite powder has an average particle size of 0.5 to 5.0 μm and a compressed density of 3.20 g/c.
The magnetic roll according to claim 1, wherein the magnetic roll is 50 to 75% by volume. 11. For 100 parts by weight of magnetoplumbite type ferrite powder, there are formulas ▲mathematical formulas, chemical formulas, tables, etc.▼ and/or ▲mathematical formulas,
There are chemical formulas, tables, etc. ▼ (In the formula, R_1, R_2 and R_3 represent an alkyl group or an alkoxy group having 3 to 20 carbon atoms). A magnetic roll according to claim 9 or 10. 12. The magnet roll according to any one of claims 9 to 11, which contains a metal salt of aliphatic carboxylic acid having 8 or more carbon atoms.