JPS5922638A - Dispersing agent for metallic oxide powder of soft ferrite material - Google Patents

Abstract

PURPOSE:To raise concn. of a metallic oxide powder slurry without deteriorating magnetic characteristics, of ferrite, by incorporating an ammonium salt of a copolymer of a 2-8C linear olefin and a 4-7C cyclic olefin and a maleic acid. CONSTITUTION:A dispersing agent used for a powder of a metallic oxide serviceable as a soft ferrite material is prepd. by dissolving a 2:1-1:2 mixture of olefin of 2-8C chain olefin, such as ethylene, propylene, butene-1, butene-2, etc., and 4-7C cyclic olefin, and maleic acid into a solvent, polymerizing them with benzoyl peroxide, and neutralizing the copolymer with an aq. soln. of ammonia or alkanolamine to give a copolymer salt. A liquid dispersion is prepd. by mixing said dispersing agent with said metallic oxide powder of the soft ferrite and water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dispersant for soft ferrite raw metal oxide powder. Soft ferrite is a metal oxide whose main component is iron oxide, and is particularly useful as a material for the magnetic core of magnetic coils.

Soft ferrite is usually manufactured by the following process.

(1) Blend raw materials such as iron oxide, manganese oxide, zinc oxide, and nickel oxide and water, (2) Grind the raw materials to about 0.5μ using a grinder such as a ball mill, sand mill, or attritor, and (3 )
This is spray-dried, (4) then press-molded and calcined, (5) further water is added, and the resultant is crushed to a size of about 2 to 4 μm using a crusher, and a binder is added, (6) (7) This is press-molded and sintered.

In the pulverizing steps (2) and (5) above, the raw material metal oxide powder is generally pulverized into a water slurry of about 50% by weight. By increasing this water slurry concentration (which means decreasing the water content in the slurry), the following favorable effects can be achieved.

(1) In the pulverization process, the pulverization efficiency increases and the time required to pulverize particles to the target particle size is shortened.

(2) The time required for spray drying is shortened.

(5) The bulk density of the spray-dried metal oxide powder is
Moreover, the press pressure during press molding can be reduced.

All of the above effects lead to improved productivity and significant savings in power energy.

However, if the slurry concentration is increased simply by reducing water, the viscosity of the slurry increases, which increases the grinding time, and makes it difficult to pump the slurry, improving productivity and reducing power energy. No savings are achieved.

As dispersants for inorganic powders such as calcium carbonate powder and titanium oxide powder, sodium polyacrylate, sodium ligninsulfonate, and sodium salt of formalin condensate of naphthalenesulfonate are commercially available. When used as a dispersant for raw metal oxide powder, the purpose of reducing slurry viscosity can be achieved to some extent, but the magnetic permeability of the final product, ferrite, deteriorates, so these dispersants cannot be used. For this reason, there is a strong demand in the industry for a dispersant that can form a highly concentrated slurry without degrading the magnetic properties of the final product, ferrite.

In view of the current situation, the inventors of the present invention have conducted extensive research and have found that
Chain olefin having 2 to 8 carbon atoms and/or 4 to 7 carbon atoms
A dispersant containing one or more ammonium salts or alkanolamine salts of a copolymer of a cyclic olefin and maleic acid can produce soft ferrite without deteriorating the magnetic properties of the final product, ferrite. The present invention was completed by discovering that it is possible to form a highly concentrated slurry of raw metal oxide powder. Examples of the chain olefins having 2 to 8 carbon atoms according to the present invention include ethylene, propylene, butene-1, and butene. -2,2
-Methyl-butene-2,4-methyl-pentene-1, hexene-1, heptene-1, octene-1,2,4,4
-trimethyl-pentene-1 and the like.

Examples of the concessional olefin having 4 to 7 carbon atoms include cyclobutene, cyclopentene, cyclohexene, and cycloheptene.

Regarding the method for producing the copolymer salt of the present invention, in the case of producing a copolymer in which the molar ratio of maleic acid and olefin is approximately equal, there is no particular restriction and the copolymer salt can be produced by a conventional method. For example, it can be produced by preparing olefin monomers and maleic anhydride in a benzene solvent, polymerizing them using benzoyl peroxide as a polymerization initiator, distilling off the benzene, and then neutralizing with aqueous ammonia or alkanolamine. can. To produce a copolymer salt with a high molar ratio of maleic acid, for example, benzene 5-, maleic anhydride, and benzoyl peroxide are prepared, and olefin is added little by little to copolymerize, and after benzene is distilled off, aqueous ammonia or Neutralize with alkanolamine. In addition, to produce a copolymer salt with a large olefin molar ratio, for example, benzene, olefin and benzoyl peroxide are prepared, and maleic anhydride is added little by little to copolymerize, and after the benzene is distilled off, aqueous ammonia or alkanol is added. Neutralize with amine.

Examples of the alkanolamine used in the production of the copolymer salt include monoethanolamine, jetanolamine, triethanolamine, and the like. It is preferable to add animonia or alkanolamine in an amount sufficient to completely neutralize maleic acid, but the amount may be such that some unneutralized material remains to the extent that performance is not impaired. The copolymer salt preferably has an average molecular weight of 500 to 1,000, more preferably 1,000 to 15,000. Copolymer salts with an average molecular weight of less than 500 and 3000
Copolymer salts exceeding 0 have insufficient ability to reduce slurry viscosity. The molar ratio of the heptamine constituting the copolymer according to the present invention is maleic acid: chain olefin having 2 to 8 carbon atoms and/or cyclic olefin having 4 to 7 carbon atoms = 2 = 1 to 1:2. preferable. If a copolymer salt outside this range is used, the effect of reducing the viscosity of the aqueous dispersion will be insufficient.

An aqueous dispersion of metal oxide powder for soft ferrite can be easily produced by mixing the metal oxide powder and water in the presence of the dispersant of the present invention. There are no particular restrictions on the dispersion procedure; for example, the metal oxide powder may be added to an aqueous solution of the copolymer salt and stirred, or the metal oxide powder may be mixed with water to form a cake. It is produced by adding and stirring an aqueous solution of a polymer salt.

The amount of the copolymer salt according to the present invention to be added depends on the particle size of the metal oxide powder, but is preferably in the range of 0.05 to 5 inches based on the weight of the metal oxide powder. It is 0.2 to 4 inches.

With the dispersant of the present invention, a highly concentrated, low viscosity slurry with a solids content of approximately 75 weight i:qb can be obtained.

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

Example 1 Penten-1 was placed in a stainless steel beaker with an internal volume of 2A.
Pour 18.8 f of a 40% aqueous solution of an ammonium salt of a copolymer of maleic acid and maleic acid (copolymerization molar ratio: bentene-1/maleic acid = 1/1, average molecular weight 6000),
Add 258.8 f of water and mix until homogeneous. Next, soft ferrite raw material metal oxide powder (on a weight basis, Fe2O, 7θ%, MnO 14%, Zn
It is a powder with an average particle size of 0.7μ containing 16 parts of O)
750? In addition, stir well with a spatil, and then use a homodisper (mixer made by Tokushu Kika Kogyo) to mix at 3/min.
The mixture was stirred for 3 minutes at a rotational speed of 0,000 rpm to obtain an aqueous dispersion containing 75 parts of metal oxide powder. 25℃ of this aqueous dispersion
The viscosity was measured using a Brookfield viscometer. The results were as shown in Table 1.

Polyvinyl alcohol (average degree of polymerization 1
By adding 7f of 0oo), stirring well with a spatyl, and spray drying with a small spray dryer,
Granules with an average particle size of 10μ were obtained. The granules were placed in a mold (length x width x depth = 10 x 40 x 10 x), pressed at a pressure of 1 t/2, and then sintered in air at 1200°C. I obtained ToX 3011mX 511 soft ferrite. The magnetic permeability of this ferrite at 25° C. was measured at a frequency of 10 KH2. The results are in Table 1
This was the general rule.

Example 2 A 40% aqueous solution of the pentene-1/maleic acid copolymer ammonium salt used in Example 1 was mixed with 10v1 water at 5441.
Metal oxide compound powder at 650 f.

Example 1 except that polyvinyl alcohol was set to 6.52
In the same manner as above, an aqueous dispersion containing 65 parts of metal oxide powder,
The viscosity of this dispersion and the magnetic permeability of the ferrite were measured under the same conditions as in Example 9-1. The results are shown in Table 1.

Example 3 Instead of the ammonium salt of pentene-17 maleic acid copolymer used in Example 1, ammonium salt of 2,2,4-trimethylpentene-1/maleic acid copolymer (copolymerization molar ratio 1/ An aqueous dispersion containing 75% of metal oxide powder and ferrite was obtained in the same manner as in Example 1 except that the aqueous solution of 25% (average molecular weight: 4000) was changed to 30f1 water to 227.5F.

The viscosity of this dispersion and the magnetic permeability of ferrite were measured under the same conditions as in Example 1. The results are shown in Table 1.

Example 4 In place of the ammonium salt of pentene-1/maleic acid copolymer used in Example 1, 4-methylpentene-1/
A 50% aqueous solution of a monoethanolamine salt of a maleic acid copolymer (copolymerization molar ratio 1/1, average molecular weight asoO) was prepared using 15t1 water at 10-242.5F, but otherwise the same procedure as in Example 1 was carried out. An aqueous dispersion containing 75% metal oxide powder and ferrite were obtained. The viscosity of this dispersion and the magnetic permeability of ferrite were measured under the same conditions as in Example 1. The results are shown in Table 1.

Example 5 Instead of the ammonium salt of pentene-1/maleic acid copolymer used in Example 1, 50% of the ammonium salt of cyclopentene/maleic acid copolymer (copolymerization molar ratio 1/1, average molecular weight 5000) was used. 15f of aqueous solution, 2 of water
42.5 F was used, and the rest was the same as in Example 1.
An aqueous dispersion containing 5 pieces of rough metal oxide powder and ferrite were obtained. The viscosity of this dispersion and the magnetic permeability of ferrite were measured under the same conditions as in Example 1. The results are shown in Table 1.

Comparative Example 1 Metal oxide blend powder 5 used in Example 1 in 500f of dewater
00f was added and the same procedure as in Example 1 was carried out to obtain an aqueous dispersion containing 50 pieces of metal oxide powder.

Next, polyvinyl alcohol 5f used in Example 1 was added to this aqueous dispersion, and soft ferrite was obtained in the same manner as in Example 1. The viscosity of the aqueous dispersion and the magnetic permeability of the ferrite were measured under the same conditions as in Example 1. The results were as shown in Table 1.

Comparative Example 2 Instead of the ammonium salt of the pentene-1/maleic acid copolymer used in Example 1, polyacrylic acid sodium salt (
A 40% aqueous solution with an average molecular weight of 4500) was heated to 18.8F.
The metal oxide powder was prepared in the same manner as in Example 1 except that 7
An aqueous dispersion and ferrite containing ferrite were obtained. The viscosity of this aqueous dispersion and the magnetic permeability of ferrite were measured under the same conditions as in Example 1. The results were as shown in Table 1.

Comparative Example 5 In place of the ammonium salt of the pentene-1/maleic acid copolymer used in Example 1, ligninsulfonic acid sodium salt (trade name: Lignaconc) was used.

15 t of 50-ti aqueous solution (manufactured by Jujo Paper Co., Ltd.), 24 t of water
An aqueous dispersion containing 75% of metal oxide powder and ferrite was obtained in the same manner as in Example 1 except that 2.5 F was used. The viscosity of this aqueous dispersion and the magnetic permeability of ferrite were measured under the same conditions as in Example 1. The results are shown in Table 1.

Comparative Example 4 Instead of the ammonium salt of the pentene-1/maleic acid copolymer used in Example 1, a powder of naphthalene sulfonic acid formalin condensate sodium salt (42% aqueous solution with a viscosity of 75 centiboise at 20°C) was used. 7.5 F
An aqueous dispersion containing 75% of metal oxide powder and ferrite were obtained in the same manner as in Example 1 except that 250f of water was used. The viscosity of this aqueous dispersion and the magnetic permeability of ferrite were measured under the same conditions as in Example 1.

The results are shown in Table 1.

Comparative Example 5 Instead of the ammonium salt of the pentene-1/maleic acid copolymer used in Example 1, an aqueous solution of ammonium ligninsulfonate [(trade name: Bolespers NH, manufactured by Borregaard, Netherlands) 4013-18 , 8f was used in the same manner as in Example 1 to obtain an aqueous dispersion containing 75% metal oxide powder and ferrite. The viscosity of this aqueous dispersion and the magnetic permeability of ferrite were measured under the same conditions as in Example 1. The results were as shown in Table 1.

Comparative Example 6 Instead of the ammonium salt of pentene-1/maleic acid copolymer used in Example 1, an ammonium salt of decene-1/maleic acid copolymer (copolymerization molar ratio 1/1, average molecular weight 3000 ) in the same manner as in Example 1 except that the 4° aqueous solution of
An aqueous dispersion containing ferrite and ferrite were obtained. The viscosity of this aqueous dispersion and the magnetic permeability of ferrite were measured under the same conditions as in Example 1. The results were as shown in Table 1.

14- Table 1 -15- 215-

Claims (1)

[Claims] 1. Chain olefin having 2 to 8 carbon atoms and/or 4 carbon atoms
A dispersing agent for soft ferrite raw metal oxide powder containing one or more of the ammonium salt or alkanolamine salt of a copolymer of a cyclic olefin and maleic acid as described in ~7. 2 The molar ratio of the monomers constituting the copolymer is maleic acid: chain olefin having 2 to 8 carbon atoms and/or cyclic olefin having 4 to 7 carbon atoms = 2 = 1 to 1:2. A dispersant for soft ferrite raw material metal oxide powder according to scope 1. 5 Dispersant for soft ferrite raw material metal oxide powder according to claim 1 or 2, wherein the copolymer salt has an average molecular weight of 500 to 3oooo