JPH0193103A - Magnetic polymer complex and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture the magnetic polymer complex having excellent mechanical properties of matter and magnetic characteristics by a method wherein the polymer containing a specific quantity of magnetic powder is filled in the polymer continuously-formed holes haying a specific diameter and a void ratio. CONSTITUTION:The liquid monomer or prepolymer containing magnetic powder of 10-98wt.% is injected into the porous polymer holes, having the continuous holes of 0.05mum-10mm in diameter and also having the void ratio of 5-98vol.%, without changing the direction of orientation. When the liquid monomer or prepolymer is polymerized or crosslinked and solidified, the magnetic polymer complex having excellent mechanical properties of matter and magnetic characteristics can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel magnetic polymer composite and a method for producing the same. This magnetic polymer composite can be suitably used as a magnetic material for motors, sensors, etc.

[Prior art] In recent years, plastic magnets made by mixing magnetic powder with non-magnetic polymer materials have been developed as an alternative to sintered magnets, but they have inferior magnetic properties compared to sintered magnets. This is the current problem.

[Problem that the invention seeks to solve]

In general, in plastic magnets, a magnetic material with sufficient magnetic properties cannot be obtained unless a large amount of magnetic powder is filled and the powder is highly oriented. However, there is a problem in that when the magnetic powder is highly filled, the physical properties and moldability of the resulting plastic magnet deteriorate, making it impossible to obtain a magnetic material with desirable characteristics.

An object of the present invention is to provide a novel magnetic material that solves the above problems.

[Means for solving problems]

That is, the magnetic polymer composite of the present invention has a pore size of 0.05
The pores of a porous body made of polymer A having continuous pores of μs to 10 mm and a porosity of 5 to 98% by volume are filled with polymer B containing 10 to 98% by weight of magnetic powder. be done.

Further, the method for producing a magnetic polymer composite of the present invention has continuous pores with a pore diameter of 0.05 μm to 10 mm, and a porosity of 5 to 10 mm.
A liquid monomer or prepolymer of polymer B containing 10 to 98% by weight of magnetic powder is filled into the pores of a porous body made of 98% by volume of polymer A, and the liquid monomer or prepolymer is placed under a magnetic field. polymerized or crosslinked,
It is characterized by having a solidifying step.

[Preferred mode for carrying out the invention]

The magnetic polymer composite of the present invention is composed of a porous body of polymer A having continuous pores and a polymer B containing magnetic powder filling the pores of this porous body. The polymer A phase (porous phase) in the polymer composite does not contain magnetic powder and therefore does not have magnetic properties, but it has good mechanical properties such as strength, and the polymer composite as a whole has good mechanical properties. It plays a role in maintaining mechanical properties such as strength.

On the other hand, the polymer B phase formed by filling the pores of the porous material has good magnetic properties, although it is inferior in mechanical properties such as strength, and the polymer composite as a whole has excellent magnetic properties. I'm making it a good thing.

In the present invention, the state in which the pores of a porous body are filled with polymer B means that the pores of the porous body are substantially completely filled with polymer B (70% or more by volume of the pores). , preferably filled to 90% or more by volume),
A state in which the polymer B is attached to the wall surface of the hole or a state in which more than 30% by volume of pores that are partially unfilled remain are excluded. If the filling of polymer B is insufficient, a polymer composite having excellent mechanical properties such as strength and magnetic properties cannot be obtained, and the object of the present invention cannot be achieved.

The porous body of polymer A used in the present invention has a pore size of 0
．． It has continuous pores of 05 μffi to 10 mm, and the porosity is 5
A porous body may be produced by any method as long as it has a volume% of ~98%. Porous bodies may be produced by, for example, adding a foaming agent and foaming by heating, or adding a solid filler. There are methods such as post-stretching. For porous bodies with discontinuous pores, it is difficult to fill the pores with polymer B, and even if the pores can be filled, the phase of polymer B will be discontinuous and non-uniform. A product with excellent magnetic properties cannot be obtained. Furthermore, even if the material has continuous pores, if most of the diameters of the pores are less than 0.05 μm, it is difficult to fill the pores with polymer B, which is not suitable. On the other hand, if most of the pore diameters exceed 10 mm, mechanical properties such as strength will deteriorate, and a rough material with poor homogeneity will be formed, which is not suitable.

In addition, the pore diameter of the hair follicle here refers to a value measured using a scanning electron microscope.

In addition, the porosity of the porous body of Polymer A is 5 to 98% by volume.
It is said that If the porosity of the porous body is less than 5% by volume, the amount of polymer B filled is too small, making it difficult to obtain a material with sufficient magnetic properties. The magnetic properties of the body tend to be non-uniform. On the other hand, if the porosity exceeds 98% by volume, the mechanical properties such as strength of the polymer composite as a whole will be insufficient.

As the polymer A forming such a porous body, various thermoplastic resins, thermosetting resins, synthetic rubbers, natural rubbers, etc. can be used without particular limitation. Specific examples include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyacecool, polycarbonate, polyphenylene oxide, methylpentene polymer, polyvinyl alcohol, polyalkylene oxide, polybutene, polyisobutylene, polysulfone, Polyether sulfone, polyphenylene sulfide, polyarylate, polyetherimide, polyetheretherketone, polyimide, crystalline polymer, fluororesin, polyurethane, unsaturated polyester resin, phenolic resin, epoxy resin, ABS resin, polybutadiene rubber, SBR , polyisoprene, chloroprene rubber, NBR, butyl rubber, natural rubber and the like.

On the other hand, polymer B used in the magnetic polymer composite of the present invention
is a monomer (including oligomers) that is liquid at room temperature.
Various types of polymers can be used as long as they are polymers that are solidified by polymerization at room temperature, or polymers that are hardened by crosslinking with a prepolymer that is liquid at room temperature. Examples include polymethyl methacrylate, polystyrene, unsaturated polyester, polyurethane, and the like. Polymer B is generally selected from a different polymer than Polymer A, but may be identical to Polymer A.

The magnetic powder used in the present invention is not particularly limited, and for example, ferrite magnetic powder (MO・nF
eOs: M is Ba%Sr, Pbb Mnb-Ni
, Zn, Mg, Cd, n represents a number from 4.5 to 6.2), rare earth cobalt magnetic powder (Rkco, : R is Sm%Prs Y%
represents one or more rare earth elements such as Lab Ce, k and m represent 1 and 5 or 2 and 17), rare earth/iron/boron magnetic powder (R-Fe-B
: R represents one or more rare earth elements such as 3m% Pr5Y, La, Nd, and C8), alnico magnetic powder, sendust magnetic powder, permalloy magnetic powder, manganese-bismuth magnetic powder. It will be done. The suitable magnetic powder has an average particle diameter of about 0.01 μm to 1 mm.

The polymer B phase preferably contains a sufficient amount of magnetic powder since it controls the magnetic properties of the polymer composite, and the content of magnetic powder in the polymer B phase is 10 to 98% by weight. range.

The polymer composite of the present invention is produced by the following method.

A predetermined amount (10 to 98% by weight) of magnetic powder and, if necessary, a polymerization catalyst and a crosslinking agent are added to the liquid monomer or prepolymer of polymer B, and the mixture is thoroughly and uniformly mixed to prepare an impregnating solution. Next, for example, after sandwiching the porous body of polymer with rolls or removing the air in the pores with a vacuum pump, the porous body of polymer A is immersed in this impregnating solution, or the porous body of polymer A is The pores of the porous body are filled with the impregnating solution by pressure-injecting the impregnating solution. In order to obtain a magnetic polymer composite having good magnetic properties, a magnetic field of sufficient strength to orient the magnetic powder is applied in this state to bring the magnetic powder into a good magnetically oriented state. Next, while maintaining the orientation of the magnetic powder, the liquid monomer or prepolymer in the pores of the porous body is polymerized or crosslinked to form solidified polymer B. The polymerization or crosslinking is preferably carried out by heating, but other polymerization or crosslinking methods such as ultraviolet irradiation, radiation irradiation, ultrasonic irradiation, microwave irradiation, etc. may also be used.

The magnetic polymer composite of the present invention may contain various additives such as stabilizers, plasticizers, lubricants, surfactants, colorants, vulcanizing agents, vulcanization accelerators, anti-aging agents, fillers, etc., as necessary. Can be blended. Moreover, the magnetic powder can also be treated with an antioxidant, a surface modifier, etc., if necessary.

〔Example〕

EXAMPLES The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited to these Examples.

Comparative Example 1 Nylon 12 (L164 (1, manufactured by Daicel Chemical)
20 parts by weight and Sr-ferrite magnetic powder (average particle size 1.2
μ) 80 parts by weight were melted in a kneader at 220 to 250°C, and then kneaded for 10 minutes. The obtained compound was compression molded at 260°C under a magnetic field (15KOe),
A test piece measuring 50 mm x 50 mm x 3 mm was prepared.

Table 1 shows the measurement results of the magnetic properties of the obtained test pieces.

Comparative Example 2 Polybutylene terephthalate (intrinsic viscosity = 1.10.2
20 parts by weight (measured in a mixed solvent of phenol/tetrachloroethane = 1/1 at 5°C) and 80 parts by weight of 3mCo5 magnetic powder (average particle size 5.0μ) were mixed in a kneader to 240 to 270 parts by weight.
After melting at ℃, the mixture was kneaded for 10 minutes. The obtained compound was compression molded at 280° C. under the same magnetic field conditions as in Comparative Example 1 to prepare a test piece. Table 1 shows the measurement results of the magnetic properties of the obtained test pieces.

Example 1 A mixture of 12 parts by weight of unsaturated polyester containing 1% by weight of methyl ethyl ketone peroxide as a polymerization initiator and 88 parts by weight of Sr-ferrite magnetic powder (average particle size 1.1 μm) was nipped with a roll. A foamed polyurethane sheet (continuous pore structure with a pore diameter of 0.1 to 9 mm, porosity 95% by volume) from which the air in the pores has been removed is immersed, and the foamed polyurethane sheet is released from the roll and restored in a liquid substance. The liquid was impregnated into the sheet.

This impregnated sheet was pressed (6 KOe) under a magnetic field (15 KOe).
0℃, 20m1n) molded to 50mmX50mmX
A 3 mmt test piece was prepared. The magnetic properties of the obtained test pieces are shown in Table 1.

Example 2 A mixture of 2 parts by weight of styrene monomer containing a polymerization initiator and 98 parts by weight of Sr-ferrite magnetic powder (average particle size 1.0 μm) was nipped with a roll to remove air in the pores. Foamed SBR rubber sheet (crosslinked material, pore size 0.1-10
A foamed SBR rubber sheet with a continuous pore structure of 0 μs and a porosity of 36% by volume was immersed to impregnate the liquid material into the foamed SBR rubber sheet.

This sheet was pressed under a magnetic field (12
0°C, 30m1n) molded to 50mm x 50mm
A test piece of x3mmt was prepared. The magnetic properties of the obtained test pieces are shown in Table 1.

Example 3 Sm*CO in 10 parts by weight of polyethylene glycol/toluylene diisocyanate = 171 molar ratio mixture (liquid)
A foamed polypropylene sheet (pore size: 0.05 mm) was prepared by removing air in the pores with a vacuum pump in a liquid mixture of 90 parts by weight of magnetic powder (average particle size: 3 hm) and 0.1 part of a polymerization catalyst (tin octylate). 1 to 100JJI11 (continuous pore structure, porosity 52% by volume) was immersed to impregnate the foamed polypropylene sheet with the liquid.

Press this sheet under a magnetic field in the same manner as in Example 1 (8
A test piece was prepared by molding (0° C., 10 ml).

Table 1 shows the measurement results of the magnetic properties of the obtained test pieces.

Example 4 SmCo5 magnetic powder (average particle size 5
．． A foamed polyethylene sheet (continuous pore structure with a pore diameter of 0.1 to 9 mm, porosity 62% by volume) that had been nipped with a roll to remove the air in the pores was immersed in a liquid containing 90 parts by weight of 0 μm). Then, as in Example 1, the sheet was impregnated with a liquid substance and pressed under a magnetic field (120°C, 30ml).
A test piece was prepared by molding. Table 1 shows the measurement results of the magnetic properties of the obtained test pieces.

Example 5 SmC in 5 parts by weight of polypropylene glycol/diphenylmethane isocyanate = l/1 molar ratio mixture (liquid)
o, expanded polystyrene that was nipped with rolls to remove air in the pores in a liquid mixture of 95 parts by weight of magnetic powder (average particle size 5.0 μff1) and 0.1 part by weight of a polymerization catalyst (tin octylate). A sheet (continuous pore structure with a pore diameter of 1 to 800 μm, porosity 73% by volume) was immersed to impregnate the liquid material into the expanded polystyrene sheet.

This sheet was pressed under a magnetic field in the same manner as in Example 1 (80
℃, 10 m1n) to prepare a test piece.

The magnetic properties of the obtained test pieces are shown in Table 1.

From Table 1, it was confirmed that the magnetic polymer composites obtained in Examples 1 to 5 had superior magnetic properties compared to the magnetic polymers of Comparative Examples 1 and 2.

〔Effect of the invention〕

As is clear from the above, the present invention can provide a magnetic polymer composite having excellent mechanical properties and magnetic properties, and its industrial value is extremely large.

Claims (2)

[Claims] (1) A porous body made of polymer A having continuous pores with a pore diameter of 0.05 μm to 10 mm and a porosity of 5 to 98% by volume, in which the inside of the pores contains 10 to 98% by weight of magnetic powder. A magnetic polymer composite filled with B. (2) A liquid containing 10 to 98% by weight of magnetic powder in the pores of a porous body made of polymer A having continuous pores with a pore diameter of 0.05 μm to 10 mm and a porosity of 5 to 98% by volume. A method for producing a magnetic polymer composite comprising the steps of injecting a monomer or prepolymer, polymerizing or crosslinking it, and solidifying it.