JP2002129063A - Low-magnetic black pigment powder, its production method and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for a low magnetic black pigment powder, displaying such as blackness as a magnetite and having no sintering and agglomeration of particles. SOLUTION: The low magnetic black pigment powder is a mixed-phase crystalline, having a rutile-type TiO2 phase as a base, wherein the base is characterized by a particle structure covered with Fe2TiO4 phase, and having a peak of Fe2TiO4 with the rutile-type TiO2 as a main peak in X-ray diffraction. A toner composition, a paint composition, a resin composition, a cosmetic and the like are produced by using the low magnetic black pigment powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-magnetic black pigment powder which is safe and harmless to the environment and the human body and has no magnetic coagulation. More specifically, the present invention relates to the coloring of a toner as an electrophotographic developer. As a dispersant, or as a coloring agent for resins such as paints and cosmetics, good dispersibility,
It is intended to provide a black pigment powder having a high blackness.

[0002]

2. Description of the Related Art In electrophotography, a developing method is a one-component developing method using a toner itself in which a colorant is dispersed in a binder resin, and a toner and a carrier are mixed, and the toner is conveyed by the carrier. And a two-component development system in which the development is performed.

[0003] In any case, when copying, the electrostatic latent image formed on the photoreceptor is developed with these toners, and the formed toner powder on the photoreceptor is transferred to a transfer material such as paper or sheet. The image is fixed using heat, pressure, etc. to obtain a permanent image. In these toners, carbon black or magnetite, which is a black colorant, is used in a large amount as an image forming material. Among them, carbon black is used in a two-component developing method or a non-magnetic one-component developing method, and magnetite is used in a magnetic one-component developing method in which toner is conveyed by magnetism.

As the demand for toner as an image forming material increases with recent advances in computers, the amount of these colorants used tends to further increase.

[0005] In recent years, problems of environmental pollution and health damage have been greatly addressed, and there is an increasing demand for the safety of raw materials used for toner.

[0006] Carbon black, which is used in a large amount as a black colorant for toners, contains a trace amount of aromatic hydrocarbons. Among them, carcinogenic properties such as 3,4 benzopyrene are pointed out. Due to the inclusion of such substances, there is an increasing trend to consider the safety of toners using carbon black.

On the other hand, magnetite is a black pigment containing iron oxide as a main component, which is safe and harmless. However, since it has high magnetism, there is a problem that particles are re-aggregated and it is difficult to obtain a uniform dispersion. Further, since magnetite has a conductive property, it cannot be used as a colorant for the above-described two-component developing system or non-magnetic one-component developing system toner requiring insulation or high resistance.

As non-magnetic black pigments replacing carbon black, JP-A-3-2276 discloses Fe ₂ TiO ₅ and Fe ₂
A black pigment particle powder composed of polycrystalline particles having a mixed composition with an O ₃ —FeTiO ₃ solid solution is disclosed in
43316 and JP-A-2000-10344 describe black particle powders having a hematite structure containing Mn.

The black pigment described in JP-A-3-2276 is obtained by coating magnetite with titanium oxide or by mixing magnetite and titanium oxide and firing in a non-oxidizing atmosphere to obtain Fe ₂ TiO ₅ and Fe ₂ O ₃ −. The present invention relates to black pigment particle powder composed of polycrystalline particles having a mixed composition with a FeTiO ₃ solid solution, which is a safe and harmless substance mainly composed of iron oxide and titanium oxide. However, magnetite with strong cohesiveness as the main material, and coated with titanium oxide at 700 ° C.
Since firing was performed at the above high temperature, hematite was generated, the color tone became reddish, blackness was insufficient, and further sintering or coalescence between particles occurred Only particles were obtained, and there was a problem in that the particles were uniformly monodispersed. Also, Japanese Patent Application Laid-Open No. 8-143
316 and JP-A-2000-10344 contain a large amount of Mn, which is an environmental pollutant, and cannot be said to be a safe and harmless pigment.

[0010]

As described above, it is safe and harmless to the environment and the human body in place of carbon black which is used in large amounts as a colorant for a two-component developing system or a non-magnetic one-component developing system. In addition, there has been no black pigment having good dispersibility, and its development is expected. Further, the present invention can be used not only as a toner but also as a coloring agent for paints and other resins and cosmetics.

[0011]

SUMMARY OF THE INVENTION Under such circumstances, the present inventors have developed a composite oxide containing titanium oxide and iron oxide as main components which is safe and harmless to the environment and the human body. Accordingly, in order to develop a black pigment having good dispersibility without sintering or coalescence between particles, intensive studies were conducted. As representatives of oxides having a black color containing titanium oxide and iron oxide as main components, FeTiO ₃ (ilmenite) and Fe ₂ TiO ₄ (Iron Titanium)
Spinel).

The inventors of the present invention focused on Fe ₂ TiO ₄ and conducted a study. As a result, titanium oxide was used as a base, and
It has been found that titanium oxide coated with Fe ₂ TiO ₄ can be obtained by forming ₂ TiO ₅ (pseudobrookite) and reducing it, thereby completing the present invention. As a result of measuring this product by X-ray diffraction, it was confirmed that TiO ₂ (rutile-type titanium oxide) was used as a main peak, and peaks of composite oxides of various titanium and iron including Fe ₂ TiO ₄ were obtained. Was.

That is, the low magnetic black pigment powder of the present invention has a particle structure in which a rutile type TiO ₂ phase is used as a base and the base is coated with an Fe ₂ TiO ₄ phase. In addition, this pigment powder can be specified as a mixed-phase crystal containing a peak of Fe ₂ TiO ₄ using rutile TiO ₂ as a main peak in the X-ray diffraction method.

The term "mixed phase crystal" as used herein generally means a polycrystal in which two or more single crystals are present. In the black pigment powder according to the present invention, X-ray is added to the surface layer of titanium oxide as a base. Fe ₂ uniform enough to be identified by X-ray diffraction
A state in which a composite oxide phase mainly composed of a TiO ₄ phase is formed. At least in this respect, it is distinguished from conventional particles that have produced a mixed composition with a solid solution or hematite.

The black pigment powder has the same degree of blackness as magnetite, has no sintering or coalescence, has a particle size of 0.1 to 0.4 μm, and has a magnetization value of 0.1 to 0.4 μm.
It was a low magnetic powder having almost no magnetism of 5 to 10.0 emu / g, and was very good as a substitute for carbon black.

Further, the black pigment powder of the present invention can be used as it is as a colorant for a toner. However, if necessary, the black pigment powder may have improved heat resistance and compatibility with a resin, and improved toner chargeability and environmental stability. Therefore, the above Fe ₂ TiO ₄
One or two or more hydrous or anhydrous inorganic oxides selected from the group consisting of silicon, aluminum, titanium, zirconium and tin are coated on the phase, and hydrophobic with silicone oil and / or a coupling agent. It is preferable to perform a surface treatment, and these various surface modification treatments may be arbitrarily combined.

The black composite oxide constituting the black pigment powder of the present invention can be obtained as follows. That is, in the production method of the present invention, after using a titanium oxide containing water or anhydrous as a base, adding an iron salt and coating it at 30 to 120 parts by weight as Fe ₂ O ₃ , an oxidizing atmosphere at 700 to 1100 ° C. Baking in titanium oxide to form a uniform Fe ₂ TiO ₅ phase on the surface of the titanium oxide, and then reducing the composite oxide and reducing the Fe ₂ TiO ₅ phase coated on the surface to Fe ₂ TiO ₄ It is characterized by being replaced.

In the production method of the present invention, in order to obtain the above black composite oxide, first, a uniform Fe ₂
It is important to form a TiO ₅ phase. For this purpose, it is necessary to use a titanium oxide having a high reactivity as a raw material, and an iron hydroxide obtained by hydrolyzing a water-soluble iron compound on the surface thereof. Alternatively, it is necessary to coat iron oxide uniformly.

The titanium oxide that can be used in the present invention preferably has a specific surface area of 20 m ² / g or more. In particular, hydrous titanium hydroxide has a specific surface area of 200 m ² / g.
It is particularly preferable in terms of high reactivity and high reactivity. In addition, when using water-containing titanium oxide obtained by the sulfuric acid method as a raw material, the sulfuric acid content contained in the water-containing titanium oxide is affected, and hematite is generated during firing. is necessary.

Examples of the water-soluble iron salt used for coating Fe ₂ TiO ₅ include ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, ferrous nitrate, and ferric nitrate. The method of hydrolysis includes a method of neutralizing and precipitating and a method of oxidizing and precipitating, and any method may be used, but the method of neutralizing and precipitating is more uniform. This is preferable because a good film can be obtained and the reactivity is good. The coating amount of iron hydroxide or iron oxide is 30 to 12 with respect to titanium oxide.
0 parts by weight is preferred. When the amount is less than 30 parts by weight, the desired black oxide cannot be obtained, and when the amount is more than 120 parts by weight, reduction is difficult to proceed, and it takes time to obtain a high blackness, which is not preferable. .

After the surface of the titanium oxide of the substrate is coated with iron hydroxide or iron oxide, it is baked to obtain Fe ₂ TiO ₅
A phase is formed, and the firing temperature at that time is 700 to 11
00 ° C, preferably 800-1000 ° C, is suitable.
When the temperature is lower than 700 ° C., the reaction of the Fe ₂ TiO ₅ phase is not completed, hematite remains, the magnetization value of the black composite oxide obtained by reduction increases, and the stability deteriorates. Not preferred. When calcined at a temperature of 1100 ° C. or more, the black composite oxide of the present invention can be obtained, but the primary particle size is larger than 0.4 μm and the dispersibility is deteriorated. It is not preferable.

Next, the Fe ₂ TiO ₅ obtained by the above calcination is used.
Reduce the phases. When reducing the titanium oxide uniformly coated with the Fe ₂ TiO ₅ phase, a reducing gas such as hydrogen gas, carbon dioxide gas, carbon monoxide gas, ammonia gas, amine gas, or a solid reducing agent containing carbon may be used. You can,
When a solid reducing agent containing carbon is used, it is preferable that carbon black does not remain. In the present invention, it is particularly preferable to use a combination of hydrogen gas and carbon dioxide gas to reduce Fe ₂ TiO ₄ generated during the reduction. The reduction can be performed at 250 to 700 ° C., but needs to be performed at an optimum temperature depending on the reducing agent used. When hydrogen gas and carbon dioxide gas are used in combination for reduction, the optimal temperature is 400 to 550 ° C. 40
If the temperature is lower than 0 ° C., the reduction does not proceed and the production of Fe ₂ TiO ₄ becomes insufficient, and the blackness decreases, which is not preferable. On the other hand, if the temperature is higher than 550 ° C., sintering of the particles at the time of reduction occurs and the dispersibility deteriorates, which is not preferable.

In the production method of the present invention, if necessary, a well-known sintering inhibitor such as an aluminum, silicon, phosphorus or zirconium salt can be used to obtain a black composite oxide having further excellent dispersibility. The addition amount is suitably 0.5 to 10% by weight based on the obtained black oxide. When the amount of the sintering inhibitor is 0.5% by weight or less, the effect of preventing sintering is weak, and when the amount is 10% by weight or more, reduction hardly proceeds, which is not preferable.

In the production method of the present invention, the above-mentioned Fe
₂ TiO ₄ phase on the surface of silicon, aluminum, titanium, zirconium and tin etc. coated with one or more of water-containing and inorganic oxides or anhydrous and inorganic oxides, or silicon oil as a hydrophobizing agent, It is preferable to coat one or more of a silane coupling agent, a titanium coupling agent, and the like, and these various surface modification treatments can be arbitrarily combined.

The above silicon, aluminum, titanium,
When coating with a water-containing or anhydrous inorganic oxide such as zirconium and tin, a known method may be used. That is, the obtained black composite oxide is slurried with water, and the water slurry is subjected to wet pulverization using a pebble mill, a sand grinder mill, an attritor or the like, and then water-soluble salts such as silicon, aluminum, titanium, and zirconium are used. May be added, neutralized with an alkali or an acid, and treated by precipitating a hydrated or non-hydrated hydroxide. In the case of performing hydrophobic treatment using a hydrophobizing agent, the treatment may be performed by a known wet method or dry method. As the hydrophobizing agent, coupling agents such as silicone oils such as methylphenyl polysiloxane, dimethyl siloxane, H-modified polysiloxane, and fluorine-modified polysiloxane, silane coupling agents, and titanium coupling agents can be used. You may use them together.

The low magnetic black pigment powder of the present invention is also effective as a black pigment in paints, resin compositions and cosmetics. For paints, it can be used not only as a general paint colorant, but also as a heat-resistant paint colorant.

The resin composition may be used not only as a coloring agent for general-purpose resins such as vinyl chloride resin, polyethylene resin and polypropylene resin, but also for a thermosetting resin such as unsaturated polyester resin, epoxy resin and polyurethane resin. Can also be used.

In cosmetic applications, it can be used as a black pigment for foundations, eye shadows, eyebrows, and the like.

[0029]

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples, but these are not intended to limit the present invention.

In the following Examples and Comparative Examples, the particle diameter is an average diameter determined from an electron micrograph, and the magnetization value was measured by using a VSM manufactured by Toei Kogyo under a magnetic field of 5 kOe. Also, the degree of blackness (L value) is determined by pressing powder.
It was measured with a color tester SC-2-CH manufactured by Suga Test Instruments Co., Ltd. Regarding the glossiness, the obtained powder was pulverized, and 5 g of a styrenated alkyd resin and 0.5 g of the pulverized product were kneaded with a Hoover Muller to form a coating. After baking for 10 minutes, the glossiness at 20 ° to 20 ° was measured by a gloss meter manufactured by Murakami Color Research Laboratory.

[0031]

Example 1 Specific surface area obtained by a sulfuric acid method: 260 m ² /
g of hydrous titanium oxide slurry as titanium oxide
g / l and neutralize the pH to 9 with 400 g / l caustic soda. After stirring for 2 hours, 200
The pH was adjusted to 6 with g / liter of hydrochloric acid, and filtration and washing were performed. The washed hydrous titanium oxide was repulped and adjusted to 100 g / l as titanium oxide, and then 1 part by weight of 1 part by weight of titanium oxide was added to the slurry using a 100 g / l solution of ferric chloride as Fe ₂ O _3. After that, 200 g / l of sodium hydroxide solution was dropped,
The pH of the slurry was adjusted to 7, and the surface of the hydrated titanium oxide was coated with iron hydroxide.

After stirring for 1 hour, filtration and washing were performed.
Dried at 10 ° C. The dried product was placed in a porcelain crucible and fired at 900 ° C. for 1 hour in an electric furnace to synthesize titanium oxide having a Fe ₂ TiO ₅ phase. After cooling, the resulting Fe ₂ Ti
Titanium oxide having an O ₅ phase was reduced with a mixed gas of hydrogen gas and carbon dioxide gas at 500 ° C. for 5 hours to obtain a black powder.

FIG. 1 is an X-ray diffraction diagram of the obtained product. In the figure, peak A indicates rutile titanium oxide, peak B indicates Fe ₂ TiO ₄ , and peak C indicates Fe ₂ TiO ₅ .
For X-ray diffraction, rutile-type TiO ₂ was used as the main peak, and F
peak of e ₂ TiO ₄ - were included click. That is, from the X-ray diffraction pattern, it was found that the product was a mixed phase crystal composed of a composite oxide containing TiO ₂ (rutile type titanium oxide) and Fe ₂ TiO ₄ phase as main components. FIG. 2 is an electron micrograph (× 30,000) of the obtained black composite oxide.
It is.

[0034]

Examples 2 to 5 and Comparative Examples 1 to 3 A composite oxide was synthesized by changing the amount of iron hydroxide coated on the surface of the hydrous titanium oxide, the calcination temperature and the reduction temperature in Example 1 as shown in Table 1. did. Table 1 shows the properties of the obtained product.

[0035]

[Table 1]

[0036]

[Reference Example] Table 1 shows magnetite for toner as a reference example.
Included. That is, in order to evaluate the point that pigment properties comparable to magnetite were obtained even though the pigment did not use magnetite, the blackness and the glossiness of the coating film were similarly measured for magnetite that is frequently used for toner. .

As is clear from the results shown in Table 1, the specific surface area, particle size and blackness of the black composite oxide of the present invention were almost the same as those of the magnetite for toner shown as the reference example. Further, since the glossiness of the coating film is much better than magnetite for toner, it is considered that there is almost no magnetic aggregation and the dispersibility is good.

[0038]

Example 6 After the black powder obtained in Example 1 was repulped in pure water and wet-pulverized by a sand mill, the mixture was heated to 70 ° C., and while stirring well, Al ₂ O _{3 was} added to the black oxide. Was added as a 2.5% by weight aluminum sulfate solution.
Subsequently, sodium hydroxide solution was added to adjust the pH to 7.
It adjusted to 5 and coated with aluminum hydroxide. After aging for 1 hour, filtration, washing, drying, and pulverization were performed to obtain an Al ₂ O ₃ -coated black oxide.

20 ° of the coating film using the obtained black oxide
When measured for glossiness at -20 [deg.], The dispersibility was improved to 51.9%.

[0040]

Example 7 In Example 6, after coating with aluminum hydroxide, hexyltrimethoxysilane was added in an amount of 5% by weight based on the black oxide, and hydrolysis was performed in water to treat the silane coupling agent. The mixture was filtered, washed, dried and pulverized to obtain a silane coupling agent-coated black oxide.

20 ° of the coating film using the obtained black oxide
When measured for glossiness at −20 °, it was 53.7%, and the dispersibility was further improved.

[0042]

The black composite oxide of the present invention is a black pigment which is safe and harmless and has low magnetic properties.
Suitable as a coloring agent for resins, cosmetics, etc.

[0043]

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction diagram of a black composite oxide obtained according to the present invention.

FIG. 2 is an electron micrograph of a black composite oxide obtained according to the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 9/02 C08K 9/02 4J037 C08L 101/00 C08L 101/00 4J038 C09C 3/06 C09C 3/06 C09D 7/12 C09D 7/12 201/00 201/00 G03G 9/083 G03G 9/08 301 9/09 361 (72) Inventor Seiji Tsujino 25, 1978 Kogushi, Oji, Ube City, Yamaguchi Prefecture Terms (reference) 2H005 AA02 AB02 CA12 CA21 CA26 CB02 CB07 CB13 EA02 EA05 EA10 4C083 AB241 BB23 CC01 4G002 AA06 AB05 AE01 4G047 CA05 CA08 CB08 CC01 CC03 CD03 4J002 BB031 BB121 BD034 CA03 CB023 CB02 EB02 EE25 EE47 4J038 EA011 HA216 KA08 KA15

Claims (12)

[Claims] 1. A low-magnetic black pigment powder characterized in that it has a particle structure in which a rutile-type TiO ₂ phase is used as a base, and the base is coated with an Fe ₂ TiO ₄ phase. 2. The low magnetic black pigment powder according to claim 1, wherein the powder is a mixed phase crystal containing rutile TiO ₂ as a main peak and Fe ₂ TiO ₄ peak in X-ray diffraction. 3. The low magnetic black pigment powder according to claim 1, wherein the powder has a particle size of 0.1 to 0.4 μm and a magnetization value of 0.5 to 10.0 emu / g. 4. The method according to claim 1, wherein one or more water-containing or anhydrous inorganic oxides selected from the group consisting of silicon, aluminum, titanium, zirconium and tin are coated on the Fe ₂ TiO ₄ phase. The low magnetic black pigment powder according to any one of claims 1 to 3. 5. The low magnetic material according to claim 1, wherein a hydrophobic treatment is performed on the Fe ₂ TiO ₄ phase with a silicone oil and / or a coupling agent. Black pigment powder. 6. A titanium oxide hydrous or anhydrous a substrate to titanium oxide iron salt as Fe ₂ O ₃ 30~12
After coating with 0 parts by weight and baking in an oxidizing atmosphere at 700 to 1100 ° C. to form a Fe ₂ TiO ₅ phase on the surface of the substrate, further reducing to form a Fe ₂ TiO ₄ phase. A method for producing a low magnetic black pigment powder. 7. The method for producing a low-magnetic black pigment powder according to claim 6, wherein a water-containing titanium oxide having a specific surface area of 200 m ² / g or more is used for the substrate. 8. The method for producing a low magnetic black pigment powder according to claim 6, wherein reduction is performed at a temperature of 400 to 550 ° C. using a mixed gas of hydrogen gas and carbon dioxide gas as a reducing agent. 9. A toner composition comprising the low-magnetic black pigment powder according to claim 1. 10. A paint comprising the low-magnetic black pigment powder according to claim 1. 11. A resin composition comprising the low-magnetic black pigment powder according to claim 1. 12. A cosmetic comprising the low-magnetic black pigment powder according to any one of claims 1 to 5.