JPS5978974A - Manufacture of ferrite - 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] The present invention relates to a method for manufacturing a ferrite sintered body.

More specifically, by using an aqueous emulsion of a thermosetting resin oligomer as a binder during sintering of ferrite, a ferrite sintered body with inferior physical strength and excellent magnetic properties can be obtained after sintering. This invention relates to a method for producing a ferrite molded sintered body.

Conventionally, during the production of ferrite sintered bodies, the pre-fired and pulverized W4 compound was molded and fired, so starch, gum arabic, gelatin, CMC, methyl cellulose, and PVA were used as binders.
Polymers such as sodium polyacrylate, hydroxypropylcellulose, polyethylene glycol, polyvinylpyrrolidone, acetylcellulose, polyvinyl acetate, coumaron resin, petroleum resin, and phenolic resin are used. These binders are used to assist the bonding between ferrite powder particles and increase the strength of the molded product, but in general, the binders are thermally decomposed during firing to form gases that form in the pores in the sintered siferite. Therefore, there is a limit to the sintered density, and the mechanical strength of the ferrite sintered body has its own limit.

The present inventors solved this conventional problem by reducing the number of pores in the sintered body and increasing the sintered density.As a result of careful consideration of the binder, we found that polybutadiene, a type of thermosetting resin oligomer, The present inventors discovered that by using an aqueous emulsion of a modified epoxy resin oligomer as a binder during sintering of ferrite, a strong ferrite molded product with excellent mechanical strength and electromagnetic properties could be obtained, leading to the completion of the present invention. That is, the present invention is a method for producing ferrite characterized by using an aqueous emulsion of polybutadiene-modified epoxy resin as a binder during sintering of ferrite.

The aqueous emulsion of polybutadiene-modified epoxy resin as a binder used in the present invention has a high sintering density.
The mechanism for producing a ferrite sintered body with excellent strength is not clear, but one assumption is that the polybutanoene molecular segment in this polybutanoene-modified epoxy resin molecule has good compatibility with the ferrite particles, which leads to its mixing with the ferrite particles. During wire forming, the oligomer particles are sufficiently distributed between the particles with the minimum required amount, and the pressure is evenly distributed throughout the powder during pressure molding, resulting in a constant molding specific gravity with little variation. , By heating and curing, bonds between powder particles/, ゛! It is thought that this will help improve the strength of the molded product and significantly increase the strength of the molded product.

In addition, the molecular segments of the epoxy resin of the polybutadiene-modified epoxy resin of the binder according to the present invention have excellent adhesiveness with ferrite particles, which strengthens the bonding force between particles and improves the strength of the sintering table. Seem.

The present invention will be explained in more detail below.

The polybutadiene-modified epoxy resin used as the binder of the present invention is as described in JP-A-55-137125. That is, it is obtained by reacting a polybutadiene homopolymer and/or copolymer having a carboxyl group in the molecule with an epoxy resin excluding an epoxy group having two α,β-epoxy groups having a methyl group at the β position. It is something.

The polybutadiene homopolymer and/or copolymer having a carboxyl group in the molecule used here is commercially available Nippon Soda under the trade name N15s.

PB -0-1000, p -2000, Guttrich products 0 names H#ar-OTB, 0TEX, 0TBN
, General Tire Company's product name 'relogen OT
, S. Philips product name Eutarez OT
There is L, HTPB.

Nippon Soda's product name Nisθ0PB-G is a polybutanoene homopolymer and copolymer with a hydroxyl group at the end.
-1000, 2000, 3000, Arco product name P
o 1y-BD, Philips Butarez HT
, Hy/)tar-HTB from Gutdrich Co., Telogen HT from General Tire Co., etc., are reacted with an acid anhydride such as maleic anhydride e in a conventional manner to half-esterify the resulting resins. Can be used as polybutadiene homopolymers and copolymers.

Furthermore, bibutanoene homo and/or co, J?, which does not have a terminal linear group? A modified resin obtained by adding maleic anhydride to a reamer can also be used. Further, the double bonds of the parent polymer may be partially or completely saturated by hydrogenation.

Also used here are α,β- having a methyl group at the β position.
Epoxy group k 211i! Eboki 7 with it (+'1
Epoxy resin strength excluding 1 resin is as follows: a) Bisphenol A type epoxy resin, for example, Neru Kagaku (trade name: Epicoat 827, 828, 834, 836, 1001, 1004, 1)
oo7; Product name of Ciba Geigy ■ Araldite 0Y252, same C! Y250. Same eY260. Same GY 280, Same 6
071.

6084, 6097 + Dow Chemical (product name of υ DER3301 331
゜337. 661. 664; Trade name of Dainippon Ink & Chemicals ■ Epicloa 800
* Same 1010, same 1000, same 3010.

b) Novolak type epoxy resin, for example Shell Chemical ■
Product name: Epicote 152, 1iiJ 154
; Dow Chemical■ product name DFiN-431+DFiN-4
38, 439; ChipaGeigy ■ trade name gpN-1138, rgaN
1235 + Trade name of Dainippon Ink Chemical Co., Ltd. Ebikulo/N-74
0, Same N-680 + Same N-695, Same N-565, Same 14-577, C) Hydrogenated bisphenol A diglycidyl ether resin, for example, Jiryu Kakogyo brand name Adekal Resin IP-4080, d) Bisphenol A-side chain type diglycidyl ether resin, for example, Chiryuka Kogyo 0 Samurai product name Adekal Resin KP-4000
, e) Urethane-modified epoxy resin, for example, Asahi Tunka Kogyo [
Product name of Aakalenone FiPU-4゜KPU-
61 EPU'-8, f) Resorcin diglycinol ether epoxy resin, e.g. SUM knee epoxy kLR=13tJ I) iiLR
-150, g) Glycytyl ester type epoxy resin, for example, Chipa Geigy (trade name: Araldai) 0Y
-183, cy-+82 r Shell Chemical (to) brand name Epicote I! 1-190
.

Same 14! -871; , 1d sum 4 engineering (Ue) Product name Noi Ufia B
-5001 same S-508, 4 S-5091 same o-6oi
x, times S-603X.

Same +111-607X, Same 5-6u9x, Same S-7
29, S-5401 S-550i Dainippon Ink & Chemicals ■ Trade name Ebikuron 200.
4001 times 1400, h) P-oxybenzoic 1-wave diglycinol ether ester resin, e.g. SUM knee epoxy resin'fLLP-160sl) Fat-type ene I-oxy resin UOC! Product name: EflL-4221, EflL-4289.
4206° 4234, 4205 i Ciba Geigy koji product name 0Y-179+40Y-1
78, 0Y-1801 0Y-175 + Chisso ■ Product name 0X-221, AX-289 + 40X-206
, 0X-301, 0X-313, j) Speculative bisphenol A type epoxy 461 Fat Shell Chemical (trade name: Ebiko) DX-245.

1045-B-80i Product name of Chihakaiya Co., Ltd. Araldite 8011゜8047 + Product name of Dainippon Ink & Chemicals ■ Ebikulo/152
+ 1120 f Dow Chemical 6υ product name DFiR-542, 5
11, 580, k) Glycidylamine epoxy resins, such as SUM xpoX7 ELMI20, SUM EItN-125, etc. can be used.

The type of polyzotage/modified epoxy resin obtained by the reaction of the above-mentioned polybutadiene homopolymer and/or copolymer with epoxy resin is optional, and the performance of the desired ferrite sintered body, A resin suitable for the properties is selected.

To describe the method for producing an aqueous emulsion of a polybutadiene-modified epoxy resin oligomer according to the present invention, the polybutadiene-modified epoxy resin is dissolved in a small amount of an organic solvent (for example, toluene, xylene, cellosolve, etc.), an emulsifier is added, and zO~ It is produced by gradually stirring water under heating at 80°C using a high-speed one-rod stirrer while stirring the mixture. In addition, if the viscosity of the polybutadiene-modified resin is low, it can be molded without a solvent.
In view of the stability of the emulsion, preserved colloid is also added as necessary.

The solid content of the produced emulsion is 20 to 80 cm, and the average particle size of the viscous particles dispersed in the emulsion is 1 to 1
It is 0μ.

The amount of the binder added to the ferrite particles according to the present invention is
- Weight %, preferably 1 to 5% by weight.

When adding the binder, a curing agent for epoxy resins may be added as a curing agent to particularly improve hardness, or a radical polymerization initiator may be added.

Epoxy resin curing agents include amines such as diethylene triamine, metaphenylene diamine, diaminodiphenylmethane, and diaminodiphenylsulfone, phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, ethylene glycol bistrimeritate, and glycerol. Tristrimelitate, dodecynylsuccinic anhydride, hexahydrophthalic anhydride, tetra'hydroheptalic anhydride, methylnadic anhydride, chlorendic anhydride, polyazelite polyanhydride, dichlorosuccinic anhydride, dodecenyl anhydride, etc. Carboxylic acid anhydride, BFs-based complex compounds such as ELF3 monoethylamine complex and BF3 pyridine complex, or complex compounds such as triethanolamine porate, dicyandiamide) diazide hydrazide, titanium alkoxide, and 18H group, - NCO group, -NL! Sg
,-C! Examples include compounds having one or more ONH7,9 in the molecule. The amount of these curing agents used is as follows:
Epoxy equivalent to functional group equivalent ratio of epoxy tree Jii7 is 0.
5 to 1.5 equivalent fk.

Examples of lanocal polymerization initiators include diacyl peroxides such as benzoyl peroxide, 2,4-nochlorobenzoyl peroxide, octanoyl peroxide, lauroyl g-oxide, and noalkyl peroxides.
A1 % For example, no tert-butyl i4-oxide, dicumyl peroxide, etc., peroxyester
, reportedly tertiary butyl perbenzoate, tertiary butyl peracetate, no tertiary butyl perbenzoate, 2,5
-methyl-2,5-(benzoylperoxide/)hexa/, etc., keto7J'-oxyfites, such as methyl ethyl ketone peroxide, cyclohexanone i4-oxide, etc., hydroperoxides, such as tert-butylhydro Peroxide, cumene hydrocarbon mother
oxide, α-phenylethylhydro/f-ogicide, cyclohexenylhydrono-oxide, etc., and their 71°C compounds are suitable and preferably non-foaming, and the amount used is 10% of the total resin content. .1 to 10% by weight, preferably (J, 5 to 5% by weight).

Moreover, a plasticizer, a lubricant, and a mold release agent can also be added as other additives. For example, as a plasticizer, dioctyl phthalate, digtylphthalate, zooctyl asopate,
Examples include glycerin, and examples of lubricants and mold release agents include stearic acid, stearic acid, calcium, and magnesium stearate.

The binder according to the present invention can be formed by any of the various conventional molding methods, such as the hot russing method, the melting molding method, the gas cracking method, the Kaga method, the dry pressing method, and the injection molding method. It is also valid even if

The process of adding the binder according to the present invention to ferrite powder, molding, and firing is generally described. After adding the molding agent, stir and mix to form a clay, putty, or slurry. These materials are molded into desired molded products using a specified ferrite molding method, and then proceed to the firing process by direct or indirect removal.The molded ferrite first goes through a drying process to remove the binder that has been dissolved or dispersed in the bath. As the solvent evaporates, curing shrinkage begins, and the ferrite particles are strongly attracted, increasing the molding density. This process is very uniform, with very little variation, and as a result, a high-density molded product of 1
4j is received. The dried molded product may be further processed into the shape of a seal. The unsintered ferrite produced in this way was heated in an inert gas (
A ferrite sintered body is obtained by firing in an atmosphere (for example, N2, CO2, etc.).

In this way, the ferrite molded and fired product using the aqueous emulsion of the polybutanoene-modified epoxy resin oligomer according to the present invention as a binder during firing has the effect of the binder as described above, and the comradery between the particles is greatly reduced. This is an extremely effective method for producing ferrite, as it has good mechanical strength and electromagnetic properties due to strong bonding.

The binder according to the present invention is of course useful for ferrite, which is considered a type of ceramic, but it is a binder that can be widely used not only for ferrite, but also for ceramics manufactured by the same manufacturing process as ferrite.

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

Hereinafter, ``chi'' or ``part'' means 9% by weight or parts by weight unless otherwise specified.

Example I N-sso Evoxin & PB-17 (manufactured by Nippon Soda Co., Ltd.)
After adding 5 parts of toluene and 5 parts of Emulgun 930 (manufactured by Kao Atlas Co., Ltd.) to 100 parts and heating to 70°C, (2) parts of distilled water at 70°C was gradually separated while stirring at high speed to form an emulsion (1). OH crush, Ritsu Fe2O3:
53-T-/l/%, NiO: 20 mol%, MnO
: 5 mol%, ZnO: 100 parts of ferrite powder with a composition of 21 mol% and the above emulsion (1 mol%) as a binder.
) A total of 4 parts were added and mixed in a kneader for 1 hour. Next, use a Nikku pelletizer (manufactured by Teiko Denki Co., Ltd.) to make a screen with a diameter of 2
I opened the ram and built it. (a) The dried sulfur sodium chloride product was dried at 105C for 2 hours, and the stearin 1
'&zinc were added to the mixture in an amount of 5 times (to granule weight) and compression molded into a disk of 8 diameters and 5 degrees thick using a 4 year old tablet (Model 6B-2 manufactured by Kikusui Seisakusho). Place this molded product in an electric furnace and keep the temperature at 5.
After firing at 00C for 2 hours, it was fired at 1300C for 5 hours.

The compressive fracture strength and magnetic properties of the sintered ferrite were measured and are shown in Table 1.

Example 2 NISSOx PO*NON gpB23 (manufactured by Nippon A-Sokusha) 1
0011 Butyl cellosolve 5 parts, Emulgun 985 (
Emulsion (II) was prepared by adding 4 parts of Kako Atlas (manufactured by Kako Atlas Co., Ltd.), heating and dissolving at 68°C, and pouring 50 parts of distilled water at 68°C while stirring at high speed.

Three parts of the above emulsion (11) as a binder were added to 100 parts of ferrite powder having the same composition as in Example 1, and mixed in a kneader for 1 hour. Next, granulation, drying, tablet-forming, and sintering were performed in the same manner as in Example 1 to obtain sintered ferrite.

The pressure m fracture strength and magnetic properties of this ferrite were measured,
The results are shown in Table 1.

Example 3 Nkosso epoxin EPB-52 (Nippon Sodasha #) 1
After adding 8 parts of xylene and 5 parts of Emuldan 935 (manufactured by Kako Atlas Co., Ltd.) to 00 parts, heating and dissolving at 70°C, press distilled water at 75°C while stirring at high speed to produce an emulsion (III). Sita.

Three parts of the above emulsion (Ill) was added as a binder to 100 parts of ferrite powder having the same composition as in Example 1, and the mixture was mixed in a kneader for 1 hour. Next, granulation, drying, tablet-forming, and sintering were performed in the same manner as in Example 1 to obtain sintered Elite 7. The compressive fracture strength and magnetic properties of this ferrite were measured, and the results are shown in Table 1.

Comparison 1: 0.5 to 100 parts of ferrite powder with the same composition as Example 1
% polyvinyl alcohol (NH- manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.)
2Q) 100 m/aqueous solution was added and mixed. Next, Example 1
Granulation, drying, tablet-forming, and sintering were performed in the same manner as above to obtain sintered ferrite. The compressive fracture strength and magnetic properties of Ko(7)7elite were measured, and the results are shown in Table 1.

Table 1 Fracture strength and magnetic properties of ferrite sintered bodies Patent applicant Haruyuki Ito, representative of Nippon Soda Co., Ltd.

Claims (1)

[Claims] An aI method for producing ferrite, characterized in that an aqueous emulsion of polybutanoene-modified epoxy resin is used as a binder during sintering of ferrite.