JPS5947707A - Composite ferrite and preparation thereof - Google Patents

Abstract

PURPOSE:To obtain a composite ferrite which has been improved in flexibility and strength by such an arrangement wherein a layer of composite ferrite of specific thickness made of a mixture composed of ferrite powder of which volume mixing ratio is limited to a certain range and high molecular substance is provided on a film of high molecular substance of specific thickness. CONSTITUTION:Liquid composite ferrite which is obtained by mixing ferrite powder of which average grain diameter is 3-20mum in high molecular material such as an adhesive, etc. within the range of volume mixing ratio of 0.2-0.8 is coated on a film 1 of high molecular material, e.g., polyester, etc. of which thickness is less than 50mum at a thickness of less than 100mum, and a layer 2 of composite ferrite is thus formed and dried. Also, a sheetlike composite ferrite like this is cut into slitlike pieces of which width is less than 100mum to form a ribbonlike material and a textilelike composite ferrite is obtained by winding, twisting together and spinning the ribbonlike ferrite with a thread of which core is made of nylon fiber, acryl fiber, polyester fiber, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite ferrite suitable for use as a radio wave absorbing material, a magnetic material for electromagnetic shielding and its ponds.

Conventionally, to improve the brittleness, poor bendability, etc. of ferrite sintered bodies], as typified by rubber magnets, polymers such as rubber and plastics and ferrite powder were used. Mixed composite ferrites have been widely put into practical use.

This type of composite 7-erite is generally formed into various shapes by extrusion molding, molding, compression molding, etc. from a mixture of ferrite powder and organic polymer material. It is tougher, has better workability, and has excellent mechanical properties compared to 7-grade light sintered bodies, but compared to the mechanical properties of rubber and polymer materials themselves, they are inorganic materials. As a result of mixing a large amount of a certain ferrite powder, it exhibits properties that are significantly deteriorated from the original properties.

The present invention aims to improve these drawbacks of conventional composite ferrite, and it is possible to form composite ferrite into a sheet or M
The object of the present invention is to provide a composite ferrite which has flexibility and strength not found in conventional ferrites and a method for producing the same.

As shown in Fig. 1, the composite ferrite of the present invention is a liquid mixture of ferrite powder with an average particle diameter of 3 to 20 μm mixed with a polymeric material such as an adhesive at a volume mixing ratio of 0.2 to 0.8. A composite ferrite layer 2 is formed by applying a composite ferrite material to a thickness of 100 μm or less on a polymer material film 1 such as polyester having a thickness of 50 μm or less, and drying the composite ferrite layer 2, and the volume mixing ratio of ferrite powder in the composite ferrite layer 2 is set to 0.2. This can be obtained by setting the value to 0.8. Moreover, such a sheet-like composite ferrite is made into a sheet with a width of 1.5 mm as shown in Fig. 2. By cutting into slint-like pieces of fl +, 1 μm or more, a composite 7-elite in which the filler layer 1 and the interlayer ferrite layer 2 are ribbon-shaped is obtained. Furthermore, ribbon-like composite 7j light is made of nylon fiber, acrylic fiber, poly L7. A fibrous composite ferrite can be obtained by blending a thread fτ1 with Ral WL navy blue as its core. .

Hereinafter, the present invention will be explained in detail according to examples.

Example 1 Sintered at 1250°C and then crushed 1' uniform particle j'diameter;
] μmo's N1-Zu based rougherite powder epoxy jj
The liquefied composite 7 elite shrine was kneaded and liquefied into the lJ finger solution at a volume mixing ratio () of 3, and was mixed with approximately 20//+n of 1
1 of 9' polyester film (1 wain 5μ+n)
After coating and drying, it was coated on a roll (1-1.High density 11 sheets) to a thickness of about 13 μm.The completed multi-needle 7
The Elai 1 sheet was slit into a width of approximately 5 μm to form a ribbon-shaped composite ferrite fiber. A sample was cut out from the completed composite 7-elite sheet and its magnetic properties were measured. As a result, a value of approximately 4 was obtained at 1 kHz.

Example 2 B with an average particle size of 1 μm sintered at 1350°C and then crushed
The a7 elite powder was kneaded into an epoxy resin solution at a volume mixing ratio of 4, and the liquefied composite ferrite was mixed into a polyester film (thickness 10
After drying, the film was densified by pressure with a roll to a thickness of about 10 μm. The completed composite ferrite sheet was slit to a width of about 5 μm to form ribbon-shaped composite ferrite fibers. A sample was cut out from this composite ferrite sheet and its magnetic properties were measured. As a result, B-r=500 Gauss, I-(c=
30+,)00e was obtained.

, according to the present invention, the volume ratio of ferrite powder is 0.2
Sufficient magnetic properties can be obtained by the composite 7-layer light layer with a thickness of ~0.8. Moreover, since it is in the form of a sheet or fiber, it is lightweight, flexible, and has sufficient strength. Furthermore, TiJ ability is to form complex shapes.
In some cases, it is also possible to fix with one type of adhesive or the like.

Soy), l-1 By blending with strong synthetic fiber, it is extremely 1. It is also possible to use a composite ferrite fiber with two strengths (1-+f) as 1n.

Applications of the present invention include radio wave absorber sheets, inctance adjustment sheets (magnetic compensation for color correction in the 1st and 3rd directions on color televisions, etc.) - Kano-shrines, structural wooden molds Radio wave absorber, 1 lance magnetic core, inbee goo case, 7 gills, itomagnetic? 1 cloth, for electric range 1 yen F
can be mentioned.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a sea-shaped composite wire 1 according to the present invention, and FIG. 2 is a perspective view showing a ribbon-shaped composite wire 1. As shown in FIG. 1... Item - HA material film, 2... Crushing punishment i
·layer. Procedural amendment (method) December 1980 130 Commissioner of the Japan Patent Office Kazuo Wakasugi 1. Indication of the case 1988 Patent Application No. 158209) 2. Title of the invention Composite ferrite and its manufacturing method 3. Person making the amendment Relationship to the incident Patent applicant address 13-1 Nihonbashi-chome, Chuo-ku, Tokyo Name (306) Tokyo Denki Kagaku Chestnut Ceremony? 1゜Representative
Sono h・11th part 7° If 'iF, (1) Imagine t
１゛Paper゛・、Application and Specification-3'l

Claims (4)

[Claims] (1) Composite ferrite with a thickness of 100μ or less, consisting of a mixture of ferrite powder and polymer material, with a volume mixing ratio of ferrite powder set to (), 2 to 0.8, on a polymer material film with a thickness of 50μ+n or less A composite ferrite characterized by having layers. (2) The ribbon-shaped composite 7-erite according to claim 1, wherein the width of the polymer material film and the composite ferrite layer is set to 100 μm or less. (3) Thickness 1 made of a mixture of ferrite powder and polymer material, with a volume mixing ratio of ferrite powder set to 0.2 to 0.8, on a polymer material film with a thickness of 50 μm or less
In addition to providing a composite ferrite layer with a thickness of less than 00 μm, the width of the polymer material film and composite ferrite layer is set to 10 μm or less.
A fibrous composite ferrite characterized by blending a ribbon-shaped composite ferrite material with a thickness of 0 μm or less with synthetic fibers. (4) Average particle size (), 1 ν of liquid composite ferrite prepared by mixing 7 EL 1 powder with an average particle diameter of 3 to 20 μIO with a polymer material at a volume mixing ratio of 11.2 to 11.8.
+ 11 QμIII for In or more F polymer material film
A method for producing a composite ferrite, characterized in that a composite ferrite layer is formed by coating the composite ferrite powder twice and dried, and the volume mixing ratio of the ferrite powder in the composite ferrite layer is set to 0.2 to 8. ,.