Compositions – Magnetic – With wax – bitumen – resin – or gum
Patent
1989-01-17
1989-11-07
Niebling, John F.
Compositions
Magnetic
With wax, bitumen, resin, or gum
335303, 264DIG58, C04B 3504, H01F 100, H01F 126
Patent
active
048790559
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to a composition having good moldability and permeability which is composed of a soft magnetic material and a liquid thermosetting resin as a binder, and to a molding process therefor.
2. Background Art
Heretofore, the soft magnetic material used for magnetic cores has been dominated by sintered moldings of spinel ferrite (e.g., Mn-Zn ferrite and Ni-Zn ferrite) which have a low loss at the high-frequency region. Since they are produced by powder metallurgy, they are poor in dimensional accuracy due to shrinkage that takes place at the time of sintering and they cannot be made in complex shape with ease. They have an additional disadvantage of being poor in impact strength which is inherent in sintered products. In order to eliminate these disadvantages, there has been proposed the so-called plastics soft magnetic material formed by bonding a soft magnetic material with a synthetic resin. For example, there is disclosed in Japanese Patent Publication No. 28356/1976 a composition composed of a spinel ferrite having a particle diameter in a specific range and a solid powdery thermosetting resin. The magnetic core formed from such a plastics soft magnetic material is inferior in saturation magnetization and permeability to sintered products, because it contains a synthetic resin as a binder which is a non-magnetic substance. If the magnetic core of the plastics soft magnetic material is to be improved in its magnetic properties, it is necessary to increase the content of the soft magnetic material powder and also to increase the molding pressure, whereby reducing the void ratio and increasing the filling density of the soft magnetic material powder.
Increasing the content of the soft magnetic material powder poses a problem in that the conventional plastics soft magnetic material is easily damaged and deformed before it is cured and solidified and that the molded item after curing is poor in mechanical strength. Also, increasing the molding pressure to reduce the void ratio breaks the particles of the soft magnetic material, deteriorating the magnetic properties of the magnetic core. In addition, increased molding pressure is liable to cause damage to the mold.
In order to solve the above-mentioned problems, the present inventors carried out a series of researches on the method of increasing the density of the molding, whereby improving the magnetic properties of the molding, while reducing the molding pressure on the mold, and also on the method of increasing the green strength of the molding before curing, whereby preventing the damage and deformation and achieving good dimensional accuracy. The present invention is based on the results of the researches.
DISCLOSURE OF THE INVENTION
The present invention covers, in the first place, a soft magnetic material composition comprising 70 to 95 vol% of soft magnetic material powder, with the balance being a liquid thermosetting resin, preferably containing a plasticizer, and, in the second place, a process for molding a plastics-containing soft magnetic material composition having high permeability, said process comprising compression molding at normal temperature a soft magnetic material composition comprising 70 to 95 vol% of soft magnetic material powder, with the balance being a liquid thermosetting resin, and subsequently heat-curing and solidifying the molded item at a temperature at which the liquid thermosetting resin cures.
The soft magnetic material powder used in this invention includes spinel ferrite such as Mn-Zn ferrite, Ni-Zn ferrite, and Mn-Mg ferrite, formed by sintering at 1100.degree. to 1300.degree. C. and subsequent crushing, and also soft magnetic alloy powder such as iron powder, Fe-Ni alloy powder, Fe-Al-Si alloy powder, and amorphous soft magnetic alloy powder. They are used individually or in combination with one another. Preferable among them is spinel ferrite powder which is commercially available. The soft magnetic material powder should have a specific particle size distr
REFERENCES:
patent: 2563520 (1951-08-01), Faus
patent: 3067140 (1962-12-01), Davis, Jr.
patent: 3668176 (1972-06-01), Childress
patent: 4200547 (1980-04-01), Beck
patent: 4267203 (1981-05-01), Motz et al.
patent: 4308155 (1981-12-01), Tada et al.
patent: 4320080 (1982-03-01), Esper et al.
patent: 4327346 (1982-04-01), Tada et al.
patent: 4431979 (1984-02-01), Stijntjes
patent: 4444670 (1984-04-01), Moslener
patent: 4462919 (1984-07-01), Saito et al.
patent: 4526837 (1985-07-01), Ohtsuki et al.
patent: 4547419 (1985-10-01), Nishimatsu et al.
patent: 4559265 (1985-12-01), Kubota et al.
patent: 4620933 (1986-11-01), Ochiai et al.
Kirk-Othmer, "Encyclopedia of Chemical Technology", Third Ed. vol. 18, (1982), pp. 113-171.
Nagai Koichi
Sakauchi Takashi
Sezaki Koji
Kanegafuchi Kagaku Kogyo & Kabushiki Kaisha
Marquis Steven P.
Niebling John F.
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