JP3096218B2 - Fine particle composite oxide green pigment and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a complex oxide green pigment, and more particularly, to an inorganic pigment which has excellent coloring properties, has a deep color tone as an inorganic pigment, and exhibits a colored green color.
Regarding fine particle composite oxide green pigment excellent in transparency and good dispersibility and its production method, by improving the color developing property, it can be used not only as a conventional pigment for ceramics, but also as a pigment for paints and inks, and even fine particles. Utilizing the characteristics that newly emerged by the conversion, for example, as a green pigment for color filters, to metallic paints and color clears that make use of the color tone of the base material, as well as pigments for phosphors, thin films, and ultraviolet absorbers And a fine particle composite oxide green pigment which is also useful for printing inks and the like.

[0002]

2. Description of the Related Art Conventionally, composite oxide green pigments are widely known as inorganic pigments having excellent heat resistance and weather resistance, and are widely used, for example, as colorants for paints and synthetic resins and as colorants for ceramics. Among them, titanium-cobalt-nickel-based and aluminum-cobalt-chromium-based composite oxide green pigments are well known. The dry method is mainly used for the production of these pigments, and is obtained by mixing, calcination and pulverization of the target oxide or carbonate compound. Therefore, large energy is required for pulverization, and fine particles cannot be obtained for pulverizing the sintered body. In addition, for inorganic pigments, fine particle technology has been developed for a single composition inorganic compound such as titanium oxide or iron oxide for a long time, but it is difficult to obtain a transparent fine particle type for a composite oxide pigment. Have been.

However, for the composite oxide green pigment of the above system, the applicants invention relates to fine particles have been filed by the (Japanese open flat 4-55322, JP-open flat 4-55323, JP- Laid-open flat 3-872
No. 8, etc.). However, these pigments are yellowish green pigments and bluish green pigments, and intermediate colors of these pigments can be obtained by toning, but they cause a decrease in transmittance and saturation due to toning. There is a strong desire for single phase particulate pigments that exhibit neutral colors.

[0004]

Means for Solving the Problems The present inventor has conducted intensive studies to meet the above-mentioned demands of the prior art, and as a result, the use of a wet precipitation method as a production method and the above-mentioned conventional components such as green pigments Color development is achieved by making a composite oxide pigment having a ternary spinel structure in which a part of the constituent elements is replaced with titanium in a pigment having a composition different from that of the oxide of cobalt and chromium. It has been found that a pigmented composite oxide green pigment with excellent properties and color can be obtained, and by further producing a particulate composite oxide green pigment having a quaternary spinel structure in which some of the constituent components are replaced with aluminum. , Compared to the former
It has been found that a colored fine particle composite oxide green pigment having higher transparency can be obtained.

Conventionally, a cobalt-chromium-based spinel-type compound includes a composite oxide blue-green pigment in which part of aluminum is replaced by chromium, and all aluminum is chromium. There is a composite oxide green pigment consisting of a spinel structure substituted with, and the latter is an inorganic pigment excellent in heat resistance and weather resistance, but is mainly used as a colorant for ceramics because the color tone is dark blue green and the color development is poor. Had been used. However, by adding a composite oxide pigment having a quaternary spinel structure in which part of the constituent elements are replaced with titanium and aluminum to the pigment having a spinel structure composed of the oxides of cobalt and chromium, the wet precipitation is further improved. By using the method, it was a fine green complex oxide green pigment which exhibited excellent transparency, heat resistance and weather resistance, and exhibited a colorful green color.

This fine particle pigment is located almost in the middle of the hue of the conventional yellow to bluish green pigment, shows a sharp waveform when the main wavelength of transmitted light is around 530 to 550 nm, and shows the main waveform of reflected light. The wavelength is colored green with a sharp waveform around 520-540 nm, and the coloring power is high.
Also, in the four-component system in which aluminum is partially substituted, the peak of the main wavelength shifts to the shorter wavelength side and the bluish color is slightly increased as compared with the three-component system, but the transmittance increases and the transparency increases. Further, it has been found that since the BET specific surface area is 30 m ² / g or more, the characteristics required in the above can be satisfied.

That is, the present invention comprises oxides of cobalt, chromium, titanium and aluminum, and the molar ratio of the constituents cobalt, chromium, titanium and aluminum is 1.0 to 3.0 chromium to 1 cobalt. , Titanium 0.
A fine particulate composite oxide green pigment characterized by having a BET specific surface area of at least 30 m ² / g and a range of 0.01 to 1.0 and aluminum of 0.01 to less than 0.5, and a method for producing the same. .

[0008]

The mixed solution of a cobalt salt and a chromium salt and a titanium compound added to a three-component mixed solution, and a mixed solution of a four-component obtained by further adding an aluminum salt in a specific ratio, are mixed using a precipitant such as an aqueous alkaline solution. By sedimentation, the inorganic pigment obtained as a three-component system is a fine-grained composite oxide green pigment that is transparent green and has a deep green color that can be sufficiently colored even when fired at a relatively low temperature. A fine particle composite oxide green pigment with improved chroma is obtained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. Salts of each of the constituent elements other than titanium used in the present invention include sulfates, nitrates, carbonates, chlorides, acetates, and the like, which are conventionally used when producing complex oxide pigments. I can do it. In the case of titanium, reagents such as titanium tetrachloride and titanyl sulfate or industrial raw materials can be used.

In the above, the molar ratio of cobalt (Co), chromium (Cr), titanium (Ti) and aluminum (Al), which are the constituents of each component, is 1.0 to 3.0 chromium to 1 cobalt. If there is a composition change in the range of 0.01 to 1.0 titanium and 0.01 to less than 0.5 aluminum, the fine particle composite oxide green pigment having more excellent transparency and saturation as described above can be obtained. It is possible to easily change the color tone from yellowish to bluish green in a composition change within this range.

Further, according to the results of the study by the present inventors, among the above constituent ratios, cobalt: chromium: titanium: aluminum = 1: 1.6 to 2.0: 0.
The ratio of 2 to 0.6: 0.1 to less than 0.5 is most preferable. At this ratio, transparency and coloring are good, and a deep green color is exhibited.

The spinel structure of cobalt and chromium has poor color development, exhibits a dull dark blue-green color, and tends to have a duller color as the amount of chromium increases, and further as the amount of titanium added exceeds the above-mentioned appropriate amount. Although the transparency tends to increase, the coloring with depth is reduced, and when the coloring is small, the color tone tends to be dull, and the colored green with depth does not develop and is unsuitable. Further, as the amount of aluminum added increases, the particle diameter decreases and the transparency increases, but the bluish color increases and tends to approach blue green.

In order to produce the particulate composite oxide green pigment of the present invention, the above-mentioned metal salts of the respective constituent elements are dissolved in water to form a mixed salt aqueous solution. The concentration at that time is preferably about 5 to 50% by weight as a whole in the above molar ratio. This mixed solution is simultaneously dropped into a previously prepared precipitation medium using an aqueous alkali solution such as caustic soda as a precipitant.

The reaction concentration at this time does not have a particularly bad influence on the transparency, but in consideration of workability and the like, the reaction concentration is suitably 0.05 mol / l to 0.5 mol / l. The thinner the film, the better the transparency. Further, if the synthesis temperature is in the range where the synthesis is carried out normally, that is, in the range of 0 ° C. to 100 ° C., the effect can be sufficiently exerted similarly to the above. In addition, if the pH at the time of the synthesis is in the range of 7 to 12, the transparency is not significantly impaired. However, as the pH shifts to the alkaline side, the transparency increases slightly while becoming dull, and conversely, as the pH shifts to the acidic side, the color becomes whitish and the transparency tends to decrease. After the precipitate is formed while stirring for 30 minutes to 1 hour in this way, the precipitate is aged for about 1 hour to complete the precipitation reaction.

Next, the precipitated coprecipitate is filtered to have a water content of about 40% to 80%.
It is dried at a temperature of about 00 ° C. to 120 ° C., and calcined in an acidic atmosphere at a temperature of 500 ° C. to 1,000 ° C. for 30 minutes to 1 hour to develop a color. As a result, it is possible to obtain the fine particle composite oxide green pigment of the present invention, which has a depth as an inorganic pigment and further improved transparency and coloring.

The fine particle composite oxide green pigment of the present invention thus obtained has a transparent and deep color tone as compared with the conventional dry method, is easy to be crushed, and has a reduced color to cobalt and chromium. By using titanium as a three-component system and adding aluminum to a four-component system, the former has excellent color developability, and as an inorganic pigment, a deep-colored pigment, as well as a pigment with improved transparency and chroma, You can do it.

[0017]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following, "parts" and "%" are based on weight unless otherwise specified. Example 1 29.10 parts of cobalt nitrate hexahydrate, aluminum nitrate 9
3.75 parts of water salt, 72.03 parts of chromium nitrate 9 hydrate and 11.54 parts of an aqueous solution of titanium tetrachloride having a titanium content of 16.6% were added to water, and this was completely dissolved to give a total of about 400 parts.
Department. Next, 37.0 parts of caustic soda is weighed out as a precipitant, and water is added to make up a total of about 400 parts.

Water 1, which is a precipitating medium prepared in advance,
200 parts were heated and maintained at 30 ° C. by a gas burner, an electric heater, or the like, and an aqueous solution of a mixed salt and an aqueous solution of caustic soda were simultaneously dropped thereto, and the precipitation reaction was completed in about 30 minutes to 1 hour. At this time, care is taken so that the pH becomes 9, and when the addition is completed, the pH is raised to about 10 so that precipitation is completely performed, and aging is performed for about 1 hour while maintaining the liquid temperature at 30 ° C. Next, when the ripening is completed, the ripened product is taken out, washed sufficiently with decantation to remove residual salts, and filtered. Next, it is dried at a temperature of 100 ° C. to 120 ° C. for 12 hours or more. The dried product is fired at 800 ° C. for one hour in an oxidizing atmosphere.

The pigment thus obtained had fine particles, a BET specific surface area of 65 m ² / g, was excellent in transparency, and was a colorful green. The fired product is then melamine alkyd resin (PHR) using a paint shaker.
30), and the color tone was observed for art paper with a black belt, which was spread with a 3 mil applicator. In addition, for those dispersed in a melamine alkyd resin (PHR30), a quartz glass
The spectral reflectance curve and the transmittance curve in the visible light region of the coating at 0 μm were measured.

Example 2 5.69 parts of titanyl sulfate having a titanium content of 33.7% were added to 200 parts of water prepared in advance, and the mixture was stirred and completely dissolved. Next, 29.10 parts of cobalt nitrate hexahydrate, 7.50 parts of aluminum nitrate nonahydrate and 72.03 parts of chromium nitrate aqueous salt were weighed, and water was added thereto so that the total amount became 400 parts. In addition, completely dissolve to form a mixed salt solution. Hereinafter, the pigment obtained by the same method as in Example 1 was also a colored green having fine particles, a large specific surface area and excellent transparency.

Comparative Example 1 29.10 parts of cobalt nitrate hexahydrate, chromium nitrate nonahydrate 7
2.03 parts and 11.54 parts of an aqueous solution of titanium tetrachloride having a titanium content of 16.6% are weighed, added to water and completely dissolved to make about 400 parts in total. Next, a sample was obtained in the same manner as in Example 1. The product thus obtained was a colored green having excellent depth of color development.

Comparative Example 2 74.93 parts of cobalt monoxide, dichromium trioxide 151.
99 parts and 31.96 parts of titanium dioxide are measured and mixed.
This is fired at 1,000 ° C. Next, the fired product was pulverized to obtain a sample. As described above, the pigment obtained by the dry method had insufficient color developability as compared with the pigment obtained in Example 1, and the whole was whitish and poor in transparency. The observation results of the color tone of the pigment obtained as described above are summarized in Table 1.

[0023]

[Table 1] Hue / Transparency: Melamine alkyd resin PHR30

[0024]

As described above, according to the present invention, a colored green fine particle composite oxide green pigment having a deep color can be obtained as an inorganic pigment having excellent coloring properties and excellent transparency. In addition to being used as a conventional pigment as a colorant for ceramics, it is also used as a colorant for general paints and synthetic resins, and by utilizing its properties, for example, as a green pigment for color filters, It is expected to be applied to metallic paints and color clears utilizing the above color tone, as well as to pigments for phosphors, ultraviolet absorbers, thin films, printing inks, cosmetics, abrasives, and the like.

[0025]

[Brief description of the drawings]

FIG. 1 shows the four-component system of Examples 1 and 2 of the present invention and Comparative Example 1.
FIG. 5 is a view showing a spectral transmittance curve in a visible light region of the fine particle composite oxide green obtained by the three-component system.

Continuing on the front page (72) Akira Nishio, Inventor 1-7-6 Nihombashi Bakurocho, Chuo-ku, Tokyo Inside Dainippon Seika Kogyo Co., Ltd. (72) Inventor Takahiro Ota 1-7-6 Nihonbashi Bakurocho, Chuo-ku, Tokyo Large (56) References JP-A-4-55323 (JP, A) JP-A-4-55324 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C01G 51/00 C09C 1/00 CA (STN)

Claims (4)

(57) [Claims] 1. It comprises an oxide of cobalt, chromium, titanium and aluminum, and the molar ratio of the constituents cobalt, chromium, titanium and aluminum is 1.0 to 3.0 for chromium to 1 for cobalt and 1.0 for titanium. 01 to 1.0 and aluminum in a range of 0.01 or more and less than 0.5,
And a fine particulate composite oxide green pigment having a BET specific surface area of 30 m ² / g or more. 2. Cobalt salt, chromium salt, titanium compound and aluminum salt are mixed with cobalt, chromium and titanium.
The molar ratio of iron and aluminum is
1.0-3.0, titanium 0.01-1.0 and aluminum
Is dissolved in water so as to be in the range of 0.01 to less than 0.5 to form a mixed salt solution, and each salt is coprecipitated using an aqueous alkali solution as a precipitant, and after aging, filtration, washing with water, drying and baking A method for producing a fine particle composite oxide green pigment. 3. A sintering temperature of 500 ° C. or more and 1,000 ° C.
The method for producing a fine particle composite oxide green pigment according to claim 2, which is as follows. 4. The method according to claim 2, wherein the pH during coprecipitation is in the range of 7 to 12.