JP2002068749A - Tin-containing granular magnetic oxide particles and method for producing the same - Google Patents

Abstract

(57) [Summary] [Problem] To have a sufficient degree of blackness, a small magnetization value, and
Provided are particulate magnetic oxide particles having excellent dispersibility. A spinel crystal represented by the following chemical formula has a Fe ²⁺ content of 17 to 22% by weight, a lattice constant of 8.41 to 8.49 °, and an applied magnetic field of 79.6 kA / m. Magnetization value is 20 to 50 Am ² / kg, and it is 10 in a pigment dispersion test using a grindometer by the Hoover-type Mallar method (JIS K5101 (1991) 9.1).
The tin-containing granular magnetic oxide particles having a groove depth value of 40 μm or less when three or more continuous lines of at least 3 mm are developed. Fe _3-x Sn _x O ₄ (where x is 0.14 to 0.48)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tin-containing granular magnetic oxide particle and a method for producing the same, and more particularly, to a tin-containing granular magnetic oxide having high blackness, a small magnetization value, and excellent dispersibility. The present invention relates to particles and a method for producing the particles. The tin-containing particulate magnetic oxide particles according to the present invention are useful as coloring pigments for paints, printing inks, rubbers and plastics, materials for magnetic toners, materials for magnetic carriers, and the like.

[0002]

2. Description of the Related Art Since granular magnetic oxide particles have a black color, they are widely used as black coloring pigments for paints, printing inks, rubber and plastics. Further, since they are ferromagnetic particles, they are used as magnetic toners and magnetic carriers for electrostatic copying by being mixed and dispersed in a resin to form composite particles.

[0003] The properties of a coating containing a color pigment depend on the dispersibility of the pigment in the coating. For example, if the pigment is well dispersed in the vehicle or resin, the color tone becomes clear and the characteristics of the material particles such as coloring power and hiding power are improved. In addition, the gloss, sharpness, mechanical properties, and air permeability of the coating are improved, and the durability of the coating is improved. Therefore, excellent dispersibility in vehicles and resins is required.

[0004] Further, with high-speed performance such as miniaturization and high speed of electrostatic copying machines, magnetic toners and magnetic carriers capable of high-density development and high resolution have been demanded. Is closely related to the properties of the magnetic particles contained in the polymer and its dispersibility.

For example, in order to enable high density development,
When the content of magnetic particles in the resin is increased, it is difficult to faithfully reproduce a fine latent image because magnetic toner exists as aggregates on the latent image after development due to magnetic aggregation of the magnetic particles. , A high-resolution image cannot be obtained. If the dispersibility of the magnetic particles in the resin is poor, the magnetic particles are not uniformly dispersed, so that the magnetic toner particles are magnetically biased or the content of the magnetic particles in the resin is reduced. As a result, high density development cannot be performed, and
High resolution images cannot be obtained.

In order to achieve high image density and high resolution, the magnetization value of the magnetic particles should be minimized so that magnetic cohesion does not occur even if the content of the magnetic particles contained in the resin is increased. It is also required to increase the content of Fe ²⁺ in the granular magnetic particles as much as possible so as to reduce the size and increase the dispersibility of the magnetic particles in the resin and to obtain a sufficient ^blackness .

[0007] The granular magnetic oxide particles having a small magnetization value include hematite or hematite + magnetite of 24.0.
９９99.2% by weight, and the Sn compound is 0.8 to 0.8% in Sn conversion.
76.0% by weight of a liquid substance or a solid substance having -CC- or -C = C- in a molecule of 0.1 to 0.1%.
4.0% by weight, and the resulting mixture is calcined at 1200 to 1450 ° C. in an inert gas (JP-A-7-115009). However, the granular magnetic oxide particles obtained by this method are 1200 to 1450 ° C.
Since the particles are obtained by sintering, a pigment dispersion test using a grindometer according to the Hoover-type Muller method (JIS K5101 (1991) 9.1) is performed.
The value of the depth of the groove when three or more continuous lines of not less than mm is expressed is 100 μm, and it is hard to say that the dispersibility is excellent.

[0008] Magnetic oxide particles having good dispersibility include silicate and Mn, Zn, Ni, Cu,
After adding at least one metal salt selected from Co, Cr, Cd, Al, Sn and Mg so as to be 0.2 to 4.0% by weight with respect to the iron element, an alkaline aqueous solution such as sodium hydroxide is added. Is added, air is blown while maintaining the pH of the resulting aqueous solution containing ferrous hydroxide at 7 or more to oxidize ferrous hydroxide to generate magnetic iron oxide seed crystals, and then ferrous sulfate A ferrous salt aqueous solution such as that described above is added, and air is blown while maintaining the pH of the resulting aqueous solution at 6 to 10 to grow a magnetic iron oxide seed crystal (JP-A-11-249335). . However, the publication states that Mn, Zn, Ni, Cu, Co, Cr, Cd,
It is suggested that an increase in the amount of one or more metal salts selected from Al, Sn and Mg lowers the dispersibility of the obtained magnetic oxide particles.

[0009]

An object of the present invention is to provide granular magnetic oxide particles having a sufficient degree of blackness, a small magnetization value, and excellent dispersibility, and a method for producing the same.

[0010]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, for example, a tin compound of 10 to 30 mol% in Sn conversion with respect to an aqueous ferrous salt solution and ferrous iron. An aqueous solution and an alkaline aqueous solution are mixed, and the obtained iron-tin-containing particulate magnetic oxide particles obtained by hydrothermal treatment of the suspension containing the tin-containing precipitate are found to be able to solve the above problems. The present invention has been completed.

The present invention has been completed on the basis of the above findings, and the gist of the present invention is that it comprises spinel type crystals represented by the following chemical formula, has an Fe ²⁺ content of 17 to 22% by weight, and has a lattice structure. The constant is 8.41 to 8.49 ° and the applied magnetic field is 79.
Magnetization value at 6 kA / m is 20 to 50 Am ² / kg, Hoover-type Mallar method (JIS K5101 (1991) 9.
According to 1), in a pigment dispersion test using a grindometer, a value of a depth of a groove when three or more continuous lines of 10 mm or more are expressed is 40 μm or less. Exist.

[0012]

Embedded image Fe _3-x Sn _x O ₄ (where x is 0.14-0.48)

Another gist of the present invention is to mix an aqueous solution of a tin compound and an alkaline aqueous solution of 10 to 30 mol% in terms of Sn with respect to an aqueous ferrous salt solution and ferrous iron, and obtain an iron-tin-containing precipitate. And a hydrothermal treatment of the suspension containing the substance.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. The tin-containing granular magnetic oxide particles according to the present invention are composed of spinel-type crystals represented by the above chemical formula. The presence or absence of the Sn element in the spinel-type crystal lattice can be confirmed by measuring a change in the lattice constant obtained from the X-ray diffraction pattern with respect to the Sn content. If the spinel-type crystal lattice does not contain the Sn element, it is impossible to obtain granular magnetic particles having a small magnetization value.

The Sn element content of the tin-containing granular magnetic oxide particles is 7 to 22% by weight (x = 0.
14 to 0.48), preferably 10 to 20% by weight. If the content of the Sn element is less than 7% by weight, a desired magnetization value cannot be obtained. Sn element content of 22
If the content exceeds 10% by weight, an Sn compound precipitates during the production of the granular magnetic oxide particles, and the dispersibility and the blackness of the granular magnetic oxide particles deteriorate.

The content of Fe ^{2+ in} the tin-containing granular magnetic oxide particles is 17 to 22% by weight, preferably 18 to 22% by weight.
It is. When the Fe ²⁺ content is less than 17% by weight, the blackness of the granular magnetic oxide particles is insufficient. When the Fe ²⁺ content exceeds 22% by weight, the blackness of the granular magnetic oxide particles is sufficiently high, but the oxidation stability is poor and handling in air becomes difficult.

The lattice constant of the tin-containing granular magnetic oxide particles is
8.41 to 8.49 °, preferably 8.43 to 8.4
8Å. The lattice constant tends to increase as the amount of Sn element contained in the spinel-type crystal lattice increases. For example, when the content of the Sn element is 7.8% by weight, the lattice constant is about 8.41 °, and the content of the Sn element is 21.
At 7% by weight, the lattice constant is about 8.49 °. When the lattice constant is less than 8.41 °, the blackness of the granular magnetic oxide particles is insufficient, and when the lattice constant exceeds 8.49 °, the oxidation stability of the granular magnetic oxide particles is deteriorated.

Applied magnetic field of tin-containing granular magnetic oxide particles 7
The magnetization value at 9.6 kA / m is 20 to 50 Am ² / k
g, preferably 25 to 45 Am ² / kg. The magnetization value tends to decrease as the content of the Sn element contained in the spinel-type crystal lattice increases, and when the content of the Sn element is 21.7% by weight, the magnetization value is about ²⁰ Am ² / kg. is there. When the magnetization value is less than 20 Am ² / kg, the magnetic toner is easily scattered, so that a high-resolution image cannot be obtained. When the magnetization value exceeds 50 Am ² / kg, the magnetic cohesion is large, the dispersibility in a vehicle or a resin is poor, and a high-density and high-resolution image cannot be obtained.

The dispersibility of the tin-containing granular magnetic oxide particles can be determined by the Hoover-type Muller method (JIS K5101 (1991)).
The value of the depth of the groove when three or more continuous lines of 10 mm or more began to appear in a pigment dispersion test using a grind meter according to 9.1). The value of the depth of the groove when three or more continuous lines of 10 mm or more of the tin-containing granular magnetic oxide particles of the present invention start to appear is 40 μm or less, preferably 30 μm or less, more preferably 20 μm or less. . If the value of the depth of the groove exceeds 40 μm when three or more continuous lines of 10 mm or more begin to appear, the dispersibility in the vehicle or the resin is poor, and a high-density and high-resolution image cannot be obtained.

The blackness of the tin-containing granular magnetic oxide particles is J
The paste obtained by the method described in ISK5101 (1991) 6.1 is coated on a mirror-coated paper using a 6-mil film applicator, and colorimetrically measured according to JIS Z 8729 using a spectrophotometer. The color index a * is shown. The a * value of the tin-containing granular magnetic oxide particles of the present invention is usually +1.5 or less, preferably +1.0 or less, more preferably +0.5 or less. a * value is +
When it exceeds 1.5, the reddish tint becomes strong and particles having a sufficient degree of blackness may not be obtained.

The average particle diameter of the tin-containing granular magnetic oxide particles is usually 0.1 to 0.3 μm, preferably 0.15 to 0.3 μm.
0.25 μm. When the average particle diameter is less than 0.1 μm, the cohesive force between the magnetic oxide particles is large and the dispersibility tends to be difficult. When the average particle size exceeds 0.3 μm, the coloring power of the magnetic oxide particles tends to decrease. In the magnetic toner, the number of magnetic oxide particles contained in one magnetic toner is reduced, and the distribution of the magnetic oxide particles in the magnetic toner particles tends to be biased,
The uniformity of the charging performance of the magnetic toner may be impaired.

Next, a method for producing the tin-containing granular magnetic oxide particles of the present invention will be described. In the production method of the present invention, first, an aqueous solution of a tin compound and an aqueous alkaline solution of 10 to 30 mol% in terms of Sn are mixed with the aqueous solution of ferrous salt and ferrous iron. In this case, it is preferable to mix an aqueous solution of a ferrous salt and an aqueous solution of a tin compound in an amount of 10 to 30 mol% in terms of Sn with respect to ferrous iron, and then to add an alkaline aqueous solution to the obtained mixed solution. That is, first, an aqueous solution of a ferrous salt is mixed with an aqueous solution of a tin compound in an amount of 10 to 30 mol% in terms of Sn with respect to ferrous iron to obtain an iron-tin mixed solution.
Specifically, ferrous salts (normally 0.1 to
(About 10 mol, preferably about 0.5 to 5 mol). Separately, a tin compound (usually about 0.001 to 5 mol, preferably about 0.5 to 2 mol in terms of iron element) is dissolved in water or an aqueous alcohol solution. The obtained ferrous salt aqueous solution and tin compound aqueous solution are mixed to obtain an iron-tin mixed solution.

Next, the alkaline aqueous solution is gradually dropped into the iron-tin mixed solution with stirring, and after dropping, the mixture is stirred at room temperature for several hours to about 1 day to contain the iron-tin-containing precipitate as the target substance. Obtain a suspension. The amount of the alkaline aqueous solution to be added is usually at least 1 equivalent relative to iron and tin in the iron-tin mixed solution, and the upper limit is preferably 2.0 equivalents, more preferably 1.6 equivalents.

The suspension containing the obtained iron-tin-containing precipitate is subjected to hydrothermal treatment to obtain the desired product. That is, the suspension containing the iron-tin-containing precipitate is subjected to the hydrothermal reaction using a hydrothermal reactor (for example, an autoclave). It is preferably carried out in the presence of an ammonium salt or a salt of the same alkali metal as the alkaline aqueous solution. Considering the particle size distribution of the resulting tin-containing granular magnetic oxide particles, the amount of the ammonium salt or alkali salt is preferably 0.5 to 1.5 mol per 1 mol of the alkaline aqueous solution. The conditions of the hydrothermal reaction are not particularly limited, but are usually 101 to 300.
C., preferably about 200-250.degree. C., usually about 0.5-48 hours, preferably about 1-10 hours. After completion of the reaction, in order to remove the remaining unreacted raw materials, the reaction product is washed with water, then filtered and dried to obtain tin-containing particulate magnetic oxide particles represented by the following formula.

[0025]

[Image Omitted] Fe _3-x Sn _x O ₄ (where x is 0.14 to 0.48)

The aqueous ferrous salt solution used in the production method of the present invention includes an aqueous ferrous chloride solution, an aqueous ferrous nitrate solution, an aqueous ferrous sulfate solution and the like. Preferably, it is an aqueous ferrous sulfate solution. Examples of the aqueous tin compound solution include an aqueous solution of stannous chloride, an aqueous solution of stannous nitrate, and an aqueous solution of stannous sulfate. Preferably, it is an aqueous solution of stannous chloride.

Examples of the alkaline aqueous solution include a lithium hydroxide aqueous solution, a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, and an ammonium aqueous solution. Particularly, an aqueous sodium hydroxide solution is preferable. These may be used alone or in combination of two or more.

The ammonium salt or alkali salt used as required may be present in a suspension containing an iron-tin-containing precipitate before the hydrothermal treatment. Examples of the alkali salt include a Li salt, a Na salt, and a K salt. When the same alkali metal salt as the alkali metal in the above alkaline aqueous solution is used, tin-containing granular magnetic oxide particles having an excellent particle size distribution can be obtained.

The tin-containing granular magnetic oxide particles thus obtained have a large content of Fe ^{2+ in} the granular magnetic particles,
Since it has a sufficient degree of blackness and has a small magnetization value, it does not generate magnetic cohesion and has excellent dispersibility in vehicles and resins.

[0030]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

The FeO content of the whole granular magnetic oxide particles was shown by the value obtained by the following chemical analysis method. That is, under an inert gas atmosphere, 25 ml of a mixed solution of phosphoric acid and sulfuric acid at a ratio of 2: 1 (weight ratio) was added to about 0.5 g of the granular magnetic oxide particles and dissolved. The solution in which the granular magnetic oxide particles were dissolved was diluted, and a few drops of diphenylaminesulfonic acid were added as an indicator to the diluted solution, and redox titration was performed using an aqueous solution of potassium dichromate. The end point was defined as the time when the above-mentioned diluted solution turned purple, and it was calculated from the amount of the aqueous potassium dichromate solution used up to the end point.

The Sn content of the granular magnetic oxide was measured with an “energy dispersive X-ray analyzer EDX” (manufactured by Hitachi, Ltd.).

The crystalline phase of the tin-containing granular magnetic oxide particles is X
It was measured by line diffraction analysis. Chemical composition was evaluated by X-ray energy dispersion spectrum analysis.

The magnetic properties of the tin-containing granular magnetic oxide particles are as follows:
The values were measured using an "oscillating sample magnetometer VSM-3S-15" (manufactured by Toei Kogyo Co., Ltd.) under an external magnetic field of 79.6 kA / m.

The dispersibility of the tin-containing granular magnetic oxide particles was determined by placing 1 mg of a sample and 10 mg of a rosin-modified phenolic resin varnish for a printing ink as a vehicle on a lower kneading plate of a Hoover-type muller and mixing with a spatula. Spread it on a kneading plate in the shape of a strip and use the Hoover-type Muller method (JIS K5
101 (1991) 9.1), in a pigment dispersion test using a grindometer, the value of the groove depth at which three or more continuous lines of 10 mm or more began to appear was measured.

The blackness of the tin-containing granular magnetic oxide particles was determined by kneading 0.5 g of a sample and 1.5 ml of castor oil with a Hoover-type muller into a paste, adding 4.5 g of clear lacquer to the paste, and kneading the mixture. A coated piece (coating thickness: about 30 μm) was prepared by coating with a 6 mil applicator on a cast-coated paper, and a multi-source spectrophotometer MSC-IS-2D (Suga Test Instruments Co., Ltd.) (Manufactured by the company) and colorimetric index a * value according to JIS Z 8729. Here, the a * value indicates the degree of reddishness, and the smaller the a * value, the better the blackness.

The shape of the tin-containing granular magnetic oxide particles was determined by observation with a transmission electron microscope (magnification: 20,000) and a scanning electron microscope (magnification: 40,000). The average particle diameter of the particulate magnetic oxide particles was determined by Martin diameter for 300 particles obtained by magnifying the photograph (magnification: 10,000 times) taken by a transmission electron microscope four times.

The particle size distribution of the tin-containing granular magnetic oxide particles is as follows:
From the average particle diameter (d) and the standard deviation (σ) obtained by the above-described method, the equation: Coefficient of change (%) = (σ / d) × 100
The change coefficient was calculated by the following equation. The smaller the value of the coefficient of change, the better the particle size distribution.
If it is 0% or less, the particle size distribution is good, and preferably 2%.
5% or less. When the coefficient of variation exceeds 30%, the particle size distribution is poor, the dispersibility as a pigment is poor, and various properties may be impaired.

Example 1 150 ml of water was added to 4.06 g of stannous chloride dihydrate and stirred to dissolve. Separately, ferrous sulfate heptahydrate 4
150 ml of water was added to 5.0 g, and dissolved by stirring.
The two solutions were mixed with stirring to obtain a Fe—Sn mixed aqueous solution (Sn: Fe (molar ratio) = 1: 9). To 22.0 g of sodium hydroxide, 300 ml of water was added and dissolved, and the resulting aqueous solution was gradually added dropwise to the above-mentioned aqueous solution of Fe-Sn while stirring.
An n-containing precipitate (Sn: Fe (molar ratio) = 1: 9) was obtained. The obtained suspension of the Fe—Sn-containing precipitate was subjected to hydrothermal treatment at 220 ° C. for 1 hour in a hydrothermal reactor (autoclave). After completion of the hydrothermal treatment, the product is washed with water to remove excess sodium hydroxide, filtered, dried,
A granular product was obtained.

The obtained granular product was octahedral fine particles, and its composition was Fe _2.84 Sn _0.16 O ₄ . The average particle size of the granular product is 0.23 μm, and the lattice constant is 8.4.
At 12 °, the Fe ²⁺ content was 21.4% by weight, the Sn element content was 7.8% by weight, the magnetization value in a magnetic field of 79.6 kA / m was 48.5 Am ² / kg, and the blackness was The a * value is +0.
It was 3. The dispersibility is measured in accordance with JIS K5101 (199
As a result of evaluating the pigment dispersion test using a grind meter according to the Hoover's method of the pigment dispersion test method 1), the presence of three continuous lines of 10 mm or more was not recognized at a groove depth of 20 μm or more. . The coefficient of change of the obtained granular product was 28%.

Example 2 150 ml of water was added to 4.06 g of stannous chloride dihydrate and stirred to dissolve. Separately, ferrous sulfate heptahydrate 4
150 ml of water was added to 5.0 g, and dissolved by stirring.
The two solutions were mixed with stirring to obtain a Fe—Sn mixed aqueous solution (Sn: Fe (molar ratio) = 1: 9). 38.0 g of sodium chloride and 22.0 g of sodium hydroxide in water 30
0 ml was added and dissolved, and the resulting aqueous solution was gradually added dropwise to the Fe-Sn mixed aqueous solution with stirring. After the addition, the mixture was further stirred for several hours, and the Fe-Sn-containing precipitate (Sn:
Fe (molar ratio) = 1: 9). Obtained Fe-Sn
The suspension containing the precipitate was hydrothermally treated at 220 ° C. for 1 hour in a hydrothermal reactor (autoclave). After the completion of the hydrothermal treatment, the product was washed with water to remove excess sodium hydroxide, filtered and dried to obtain a granular product.

The obtained granular product was octahedral fine particles, and its composition was Fe _2.84 Sn _0.16 O ₄ . The average particle size of the granular product is 0.23 μm, and the lattice constant is 8.4.
At 12 °, the Fe ²⁺ content was 21.4% by weight, the Sn element content was 7.8% by weight, the magnetization value in a magnetic field of 79.6 kA / m was 48.5 Am ² / kg, and the blackness was The a * value is +0.
It was 3. The dispersibility is measured in accordance with JIS K5101 (199
As a result of evaluating the pigment dispersion test using a grindometer according to the Hoover-type Mallar method of the pigment dispersion test method of 1), the presence of three continuous lines of 10 mm or more was not recognized at a groove depth of 20 μm or more. . The coefficient of change of the obtained granular product was 22%.

Example 3 150 ml of methanol was added to 6.83 g of anhydrous stannous chloride and dissolved by stirring. Separately, 150 ml of water was added to 40.0 g of ferrous sulfate heptahydrate and stirred to dissolve. The two solutions were mixed with stirring to obtain a Fe—Sn mixed aqueous solution (Sn: Fe (molar ratio) = 2: 8). To 38.0 g of sodium chloride and 22.0 g of sodium hydroxide, add water 3
Then, the resulting aqueous solution was gradually added dropwise to the above Fe-Sn mixture while stirring, and after the addition, the mixture was further stirred for several hours to obtain a Fe-Sn-containing precipitate Sn: Fe (molar ratio) = 2: 8). The obtained suspension of the Fe-Sn-containing precipitate was placed in a hydrothermal reactor (autoclave) for 22 minutes.
Hydrothermal treatment was performed at 0 ° C. for 1 hour. After completion of the hydrothermal treatment, the product was washed with water to remove excess sodium hydroxide and other alkali salts, filtered and dried to obtain a granular product.

The obtained granular product was octahedral fine particles, and its composition was Fe _2.65 Sn _0.35 O ₄ . The average particle size of the granular product is 0.18 μm, and the lattice constant is 8.4.
At 70 °, the Fe ²⁺ content was 20.5% by weight, the Sn element content was 16.4% by weight, the magnetization value in a magnetic field of 79.6 kA / m was 35.1 Am ² / kg, and the blackness was The a * value is:
0.5. Dispersibility is measured according to JIS K5101-19.
As a result of the evaluation by the Hoover-type Mueller method of the pigment dispersion test of No. 91, no continuous line of 10 mm or more was observed at 30 μm or more. The coefficient of change of the obtained granular product was 21%.

Example 4 150 ml of methanol was added to 10.23 g of anhydrous stannous chloride and dissolved by stirring. Separately, 150 ml of water was added to 35.0 g of ferrous sulfate heptahydrate and stirred to dissolve. The two solutions were mixed with stirring to obtain a Fe—Sn mixture (Sn: Fe (molar ratio) = 3: 7). 38.0 g of sodium chloride and 22.0 g of sodium hydroxide in water 30
0 ml was added and dissolved, and the obtained aqueous solution was gradually added dropwise to the above-mentioned Fe-Sn mixture while stirring, and after the addition, the mixture was further stirred for several hours to obtain Fe-Sn coprecipitate Sn: Fe (molar ratio) = 3: 7). The obtained Fe—Sn coprecipitate was subjected to hydrothermal treatment at 220 ° C. for 1 hour in a hydrothermal reactor (autoclave). After the hydrothermal treatment, the product is washed with water,
Excess sodium hydroxide and other alkali salts were removed, filtered and dried to obtain a granular product.

The obtained granular product was octahedral fine particles, and the composition was Fe _2.52 Sn _0.48 O ₄ . The average particle size of the granular product is 0.13 μm, and the lattice constant is 8.4.
At 87 °, the Fe ²⁺ content was 18.1% by weight, the Sn element content was 21.8% by weight, the magnetization value in a magnetic field of 79.6 kA / m was 21.5 Am ² / kg, and the blackness was a * value is +
0.7. Dispersibility is measured according to JIS K5101-19.
As a result of the evaluation by the Hoover-type Mueller method of the pigment dispersion test of No. 91, no continuous line of 10 mm or more was observed at 30 μm or more. The coefficient of change of the obtained granular product was 23%.

[0047]

As described above, the tin-containing granular magnetic oxide particles have a large Fe ²⁺ content, are excellent in particle size distribution, have sufficient blackness, and have a small magnetization value, so that magnetic cohesion can be generated. And excellent dispersibility in vehicles and resins. Therefore, it is useful as a coloring pigment for paints, printing inks, rubbers and plastics, a material for magnetic toners, a material for magnetic carriers, and the like. In addition, since tin-containing granular magnetic oxide particles can be produced at a relatively low temperature, this is an industrially useful method.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 1/11 H01F 1/11 N // G03G 9/083 G03G 9/08 301 9/107 302 9/10 331 (72) Inventor Tomonari Takeuchi 1-8-31 Midorigaoka, Ikeda-shi, Osaka Prefecture Inside the Kansai Center, National Institute of Advanced Industrial Science and Technology (72) Inventor Hiroyuki Kageyama 1-38-31 Midorioka, Ikeda-shi, Osaka Inside the Kansai Center of the National Institute of Advanced Industrial Science and Technology (72) Inventor Tatsuya Nakamura 1-4 Meiji Shinkai, Otake City, Hiroshima Prefecture Inside the Otake Creative Center Toda Kogyo Co., Ltd. (72) Hiromitsu Misawa Meiji Shinkai, Otake City, Hiroshima Prefecture No. 1-4 F-term in Toda Kogyo Co., Ltd. Otake Creation Center (reference) 2H005 AA02 AA03 AB02 BA02 CB03 CB07 EA02 EA05 EA10 4G002 AA06 AB02 AE01 AE02 4J037 AA08 AA14 CA18 DD02 DD05 EE16 EE28 EE43 FF05 FF11 FF15 5E040 AA11 AB03 CA07

Claims (6)

[Claims] 1. A spinel-type crystal represented by the following chemical formula, having an Fe ²⁺ content of 17 to 22% by weight, a lattice constant of 8.41 to 8.49 °, and an applied magnetic field of 79.6 kA / m.
Is ²⁰ to 50 Am ² / kg in a pigment dispersion test using a grindometer according to the Hoover-type Mallar method (JIS K5101 (1991) 9.1).
The tin-containing granular magnetic oxide particles having a groove depth value of 40 μm or less when three or more continuous lines of at least 3 mm are developed. [Image Omitted] Fe _3-x Sn _x O ₄ (where x is 0.14 to 0.48) 2. The tin-containing granular magnetic oxide particles according to claim 1, having an average particle diameter of 0.1 to 0.3 μm. 3. The tin-containing granular magnetic oxide particles according to claim 1, having a blackness (a * value) of +1.5 or less. 4. A suspension containing an iron-tin-containing precipitate obtained by mixing an aqueous solution of a tin compound and an aqueous alkaline solution in an amount of 10 to 30 mol% in terms of Sn with respect to an aqueous ferrous salt solution and ferrous iron. Wherein tin is subjected to a hydrothermal treatment. 5. The method according to claim 4, wherein the hydrothermal treatment is performed in the presence of an ammonium salt or a salt of the same alkali metal as the alkaline aqueous solution. 6. Hydrothermal treatment at 101-300 ° C. for 0.5-
The production method according to claim 4, which is performed in 48 hours.