JPH03290312A - Spherical activated alumina carrier, production thereof and combination pigment using the same - Google Patents

Abstract

PURPOSE:To obtain a spherical activated alumina carrier, having a large specific surface area and excellent in coloring matter adsorptivity by treating spherical metallic Al having a specified average particle diameter and specific surface area with an alkali within a specific pH range, then drying and burning the resultant substance. CONSTITUTION:Spherical metallic aluminum having 0.1-50mum average particle diameter and 1-20m<2>/g specific surface area is produced by a method for atomizing aluminum and classifying the obtained powder with a screen, etc. The resultant spherical metallic aluminum is then treated with an alkali at pH7.1-11 and subsequently dried and/or burned to afford a spherical activated alumina carrier having 0.1-50mum average grain diameter and 30-350m<2>/g specific surface area. An organic coloring matter can be then adsorbed on the resultant spherical activated alumina carrier to produce a combination pigment excellent in brightness, saturation, water, solvent and weather resistance and safety, etc. The obtained combination pigment is preferably used as coatings, cosmetics, etc.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a new activated alumina carrier, and more particularly to a spherical activated Anovena carrier that has high dye adsorption properties and is highly useful as a pigment carrier, and its use. The production method, and the spherical activated alumina carrier encapsulating an organic pigment has high brightness, saturation, water resistance, solvent resistance, weather resistance, and safety;
It also relates to a pigment that has good extensibility (spreadability, slippage) and is excellent in feel when used.

[Prior art and problems to be solved by the invention] Although organic pigments are superior to inorganic pigments in terms of vividness and variety of colors, they have poor water resistance, solvent resistance, weather resistance,
Many of them are inferior in stability such as heat resistance. On the other hand, while many inorganic pigments have excellent stability, they generally have drawbacks such as dull color tone and limited color types. Therefore, attempts have been made to combine these organic and inorganic pigments in order to obtain pigments that have the respective excellent properties.

For example, methods include coating the surface of inorganic powders such as titanium oxide and barium sulfate with organic pigments and making them insolubilized to improve layering power and weather resistance; A method of obtaining pigments by embedding organic pigments in the body by ion exchange or adsorption is known.

However, with this method of coating inorganic powder with organic pigments, the coated organic pigments tend to peel off, and because the organic pigments are exposed on the surface, it is difficult to improve water resistance, solvent resistance, weather resistance, etc. There is a problem in that pigments have their own limitations and cannot sufficiently cover the drawbacks of organic pigments. In addition, the method of embedding organic pigments in inorganic powder is
In addition to often sacrificing the vividness of the organic dye, if the organic dye is not completely confined, there are disadvantages in that water resistance, solvent resistance, and weather resistance deteriorate.

Therefore, the present inventors have conducted various studies to solve these technical difficulties, and have developed a material that has excellent adsorption power for pigments, does not affect the color tone of the adsorbed pigment, and is stable as a pigment carrier. He discovered porous alumina that met the required properties and filed a patent application (Japanese Patent Application No. 20555/1983). This product had high stability as a pigment and a clear color tone, but as a result of a sensory test for the feeling of use when used as a cosmetic, it was found that the spreadability factors such as spreadability and slippage were insufficient. It was found that there is a concentration limit to its use in cosmetics.

Traditionally, alumina has been produced by: ■ neutralizing an aqueous solution of aluminum salt with ammonia or an alkali, ■ precipitating it from a supersaturated solution of sodium aluminate, or using aluminic acid.
Aluminum hydroxide (or alumina It is produced by dehydrating a hydrate).

However, conventional aluminas obtained by these methods have a fine powder or granular shape, have insufficient extensibility, and have problems in feel when used.

Further, spherical alumina is produced by (1) dehydrating alumina hydrate obtained using the urea method, which is one of the homogeneous precipitation methods, or (2) high-temperature spraying. Among these, in the homogeneous precipitation method (1), spherical alumina hydrate is obtained by adding urea to an aluminum sulfate solution, or adding ammonium sulfate and further urea to aluminum nitrate and heating the mixture. However, the alumina obtained by this method contains aluminum sulfate and basic aluminum sulfate as impurities, and has a specific surface area of 10 m2.
''/g or less, not only did it have poor performance as a carrier, but the resulting alumina tended to agglomerate, resulting in a problem with the usability. Also, in the high-temperature spraying method, no aggregation occurred; Although the usability is excellent, the specific surface area is 30rn'/
g or less, and its performance as a carrier was poor.

On the other hand, JP-A-51-100995 discloses a method of reacting metallic aluminum in alkaline, neutral, and acidic aqueous solutions to obtain hydrated aluminum in the form of fine powder, plate, and gel, respectively. However, spherical ones have not been obtained. Furthermore, the alumina obtained by this method not only has a specific surface area of 30 m"/g or less, so it not only has poor performance as a carrier, but also has extremely fine particle size, so it has poor extensibility and causes problems such as squeaks. It also had the problem of being inferior in sensuality.

Therefore, it has been desired to develop a new activated alumina carrier that has excellent characteristics as a pigment carrier and provides a good feeling when used in cosmetics.

[Means to solve the problem]

Under these circumstances, as a result of various studies, the present inventors have found that if spherical metal aluminum having a specific average particle size and specific surface area is treated with alkali and then dried and/or calcined, a highly active spherical activated alumina carrier can be obtained. It was also discovered that by encapsulating an organic pigment in the carrier and then subjecting it to hydrothermal treatment, a composite pigment with excellent functionality and significantly improved water resistance and solvent resistance could be obtained, and the present invention completed.

That is, the present invention provides a spherical activated alumina carrier having an average particle size of 0.1 to 50 μm and a specific surface area of 30 to 350 m''/g, a method for producing the same, and a composite pigment using the carrier.

In the present invention, the average particle diameter is a value measured by ultrasonically dispersing a powder suspension and using a laser diffraction particle size distribution measuring device. Moreover, the specific surface area is N.

These are the values obtained by the B, E, T method by adsorption.

The pH of the suspension is the value when a 5% by weight aqueous suspension is measured at 25°C.

Furthermore, in the present invention, the spherical shape includes twin spheres and fused spheres, but is substantially based on a sphere.

Activated alumina in the present invention not only has a large specific surface area, but also has the ability to at least partially become hydrated alumina through a hydrothermal reaction, such as amorphous, χ-9ρ-1η-alumina, Boehmite etc.

Furthermore, it also includes alumina that has solid acid sites formed on its surface to enhance its adsorption properties.

The average particle size of the spherical activated alumina carrier of the present invention is 0.1 to 5.
It is necessary that the thickness is 0 μm, and particularly preferably 1 to 20 μm. When the average particle size exceeds 50 μm, adhesion to the skin is poor when used as a cosmetic, and when the average particle size is smaller than 0.1 μm, extensibility deteriorates.

Its specific surface area needs to be 30 to 350 m''/g in order to sufficiently adsorb organic dyes, especially 2
00 to 350 m''/g. If the specific surface area is less than 30 m'/g, organic dye adsorption will not be sufficient, and it is technically difficult to prepare one with a specific surface area of more than 350 m'/g. .

In addition, the spherical activated alumina carrier of the present invention adsorbs organic dyes even if it does not have solid acid sites, but those with solid acid sites with a suspension pl of 3.0 to 5.0 are more effective. High adsorption of organic dyes.

The spherical activated alumina carrier of the present invention has a specific surface area of 1
~20m1/g and an average particle size of 0.1 to 50 μm, spherical metal aluminum is treated with alkali at pH 7.1 to 11.0, and then dried and/or calcined, or the spherical active metal obtained by this method is It is produced by further treating the alumina support with an acid, followed by drying and/or firing.

In the present invention, the spherical metal aluminum that is the starting material can be obtained by atomizing aluminum powder and classifying it with a sieve.

This spherical metal aluminum is treated in an alkaline aqueous solution while being stirred. Examples of the alkali used include hydroxides of alkali metals and alkaline earth metals, alkali metal carbonates, ammonia, amines, and urea, and particularly preferred are amines such as ammonia, urea, and monoethanolamine. Further, the pH of the alkaline aqueous solution needs to be 7.1 to 11.0 in order to suppress rapid reactions, and is particularly preferably 9.0 to 10.0. In addition, the reaction temperature was set at 40 to 1
00°C, particularly preferably 70 to 90°C. Furthermore, favorable results can be obtained by adding a surfactant for the purpose of preventing agglomeration of the spherical activated alumina carrier during the alkali treatment reaction. As the surfactant to be added, anionic surfactants are preferable, and polycarboxylic acid type polymeric surfactants are particularly preferable.

After performing such alkali treatment, it is filtered and dried. Furthermore, if this is subjected to a baking treatment, the dye adsorption power can be further increased. The firing temperature is preferably 150 to 800°C, particularly 300 to 600°C for 10 minutes to
After 2 hours of calcination, a spherical activated alumina support with the best properties is obtained.

In order to produce the spherical activated alumina support of the present invention having solid acid sites whose suspension has a pH of 3.0 to 5.0, the flaky activated alumina suspension obtained above is mixed with hydrochloric acid, sulfuric acid, It may be dried and/or fired after being treated with a mineral acid such as nitric acid or an organic acid such as oxalic acid or citric acid.

Acid treatment with these organic acids has an equilibrium pH of 2 to 5.
．． It is preferable to carry out the test under conditions that result in a rating of 5.

If the pH is less than 2, dissolution of alumina and carrier particles may occur, and if it exceeds 5.5,
This is not preferable because subsequent activation becomes difficult and the adsorption power of the dye is likely to be impaired.

After such acid treatment, the obtained product was filtered and dried.
By firing, a spherical activated alumina carrier with even greater adsorption power for dyes can be obtained. Here, the firing temperature is 150 to 800
℃, preferably 10 minutes to 350 to 600℃
Baking for 2 hours is particularly preferred.

If an organic dye is encapsulated by adsorption to the spherical activated alumina carrier of the present invention obtained as described above,
A composite pigment with clear color and stability can be obtained.

Examples of organic dyes to be incorporated into the spherical activated alumina carrier include acid dyes, natural dyes, oil-soluble dyes, vat dyes, etc. Coloring with any dye is possible, but acid dyes,
Natural dyes are particularly preferred.

As acidic dyes, Red No. 2, Red No. 3, Red No. 102, Red No. 104, Red No. 105, Red No. 106, Yellow 4
No., Yellow No. 5, Green No. 3, Blue No. 1, Blue No. 2, Red No. 2
No. 27, Red No. 230, Red No. 231, Red No. 232,
Daidai-iro No. 205, Daidai-iro No. 207, Yellow 202
No., Yellow No. 203, Green No. 201, Green No. 204, Green No. 205, Red No. 202, Blue No. 205, Brown No. 201, Red No. 410, Red No. 502, Red No. 503, Red No. 5
No. 04, red No. 506, orange No. 402, yellow No. 40
Examples include No. 2, Yellow No. 403, Yellow No. 406, Yellow No. 407, Green No. 402, Purple No. 401, and Black No. 401, and these may be mixed and used if necessary.

Natural pigments include quinone pigments such as laccaic acid, carminic acid, kermesic acid, alizarin, shikonin, alkanine, and exochrome; β-carotene, β-apo-8
- carotenal, cabsanthin, lycopene, bixin,
Carotenoid pigments such as crocin and canthaxanthin; flavonoid pigments such as shisonin, lafuanine, ethudianin, safrole yellow, rutin, quercetin, and cacao pigments; flavin pigments such as riboflavin;
Examples include porphyrin pigments such as chlorophyll; diketone pigments such as curcumin; and betacyanidin pigments such as betanin, and these may be used in combination if necessary.

Examples of oil-soluble dyes include Red No. 215 and Red No. 21.
No. 8, Red No. 223, Orange No. 201, Orange No. 206, Yellow No. 201, Yellow No. 204, Green No. 202, Purple No. 201, Red No. 501, Red No. 505, Orange No. 403, Yellow No. 404, Yellow No. 405, Blue No. 40
No. 3, etc. can be mentioned, and they can be used in combination if necessary.

The adsorption step is carried out by bringing a solution of 0.001 to 10% by weight, preferably 0.101 to 3% by weight, of the organic dye into contact with the spherical activated alumina carrier prepared as described above.

As the coloring solution, an aqueous solution is preferable in the case of acidic dyes or natural dyes, and an organic solvent solution is preferable in the case of oil-soluble dyes.
In some cases, a mixed solution of water and an organic solvent may also be used. Furthermore, when producing vat dyes, an aqueous solution of the reduced product is used.

If necessary, surfactants, inorganic salts, etc. may be added to the dye solution to improve dyeing properties.

The contact and action operation between the spherical activated alumina carrier and the dye solution can be carried out by methods such as immersion, dropwise mixing, or fluidized bed mixing. In any method, the contact and action time is 1 to 60 minutes, The temperature of the dye solution is preferably 80°C or lower. By this contact and action operation, the organic dye is added to the carrier at a weight ratio of 0.001 to 1 g/g carrier, especially 0.0
A pigment containing 5 to 0.8 g/g of carrier has preferable properties when used as a pigment.

The activated alumina carrier containing the organic dye can be partially hydrated by further hydrothermal treatment. This hydration reaction prevents elution of the organic dye.

Hydrothermal treatment can be carried out using hot water at 70 to 180°C, but
In particular, it is preferable to use pressurized steam at 100 to 180°C because the hydrothermal treatment becomes more sufficient.

However, some organic dyes change color when the temperature exceeds 150°C, so care must be taken. Further, the time required for the hydrothermal treatment may be shorter as the temperature is higher, and is determined depending on the temperature, but preferably 5 minutes to 2 hours.

After hydrothermal treatment, the powder is finally washed and filtered at 120°C.
Dry below. At this time, in order to speed up the drying of the filtrate and prevent secondary agglomeration, washing the filtrate with an organic solvent such as acetone or ethanol will yield a powder with good physical properties.

The thus obtained composite pigment of the present invention has excellent color tone, coloring power,
It has excellent usability, water resistance, solvent resistance, and safety, and cosmetics containing it have a clear appearance with no color separation and a good feeling of use.

Furthermore, a paint containing this product has a clear external color and good weather resistance, water resistance, and solvent resistance.

[For production]

The alumina support of the present invention is spherical, has a large specific surface area, is active, and can be hydrated by hydrothermal treatment. Therefore, it has high dye adsorption ability, eliminates dye elution, has excellent color tone, water resistance, solvent resistance, weather resistance, and safety, and has good extensibility and excellent usability. pigments can be obtained.

〔Effect of the invention〕

The spherical activated alumina carrier of the present invention is comfortable to use, has a large specific surface area, has excellent adsorption properties, and has functionality such as hygroscopicity, oil absorption, aroma retention, and retention of medicinal ingredients. It is useful as an extender pigment.

In addition, the composite pigment using the spherical activated alumina carrier of the present invention does not cause color separation during use, has excellent external color clarity, water resistance, and solvent resistance, and can be used in various cosmetics, paints, plastics, Useful for ink, paint, daily necessities, decorative items, etc.

〔Example〕

Next, the present invention will be explained with reference to Examples.

Example 1 10.0 g of spherical metal aluminum (manufactured by Alcoa, aluminum atomized powder, average particle size 8.0 μm, 325 mesh pass product) was mixed with 160 g of ethanol and 20 g of water.
0 g of the mixed solution. Furthermore, 0.1 g of a special polycarboxylic acid type polymeric surfactant (Demol EP manufactured by Kao)
Added and stirred for 30 minutes. Furthermore, 0.9 g of monoethanolamine was added. At this time, the pH at 25°C is
It was 10.0.

The mixture was stirred at 100°C for 10 hours, filtered under suction, and dried at 90°C for 2 hours to obtain 15.5 g of white powder (spherical powder A). Further, it was calcined for 2 hours at 400°C in a nitrogen atmosphere to obtain spherical powder 11 with a specific surface area of 200 rn''/g and an average particle size of 9.5 μm.
．． 0 g (spherical powder B) was obtained.

Example 2 170 g of water was added to 10.0 g of powder A obtained in Example 1 and stirred. The pH at 25° C. at this time was 7.0. Add 4ml of IN hydrochloric acid to this! Add to pH 3.60
After that, the mixture was stirred for 2 hours. The final pH reached equilibrium at 4.20. It was filtered and dried at 90°C for 2 hours.

Furthermore, it was baked at 400°C for 2 hours in a nitrogen atmosphere, and 7.
A spherical powder of Og (spherical powder C) was obtained. This product had a specific surface area of 220 m''/g and an average particle size of 9.5 μm.The pH of a 5% aqueous suspension of this spherical powder at 25° C. was 4.6.

Example 3 Spherical powder B1 obtained in Example 1. Og was suspended in 50 g of water, and 0.35 g of natural pigment cochineal (carminic acid, manufactured by Sanei Chemical) dissolved in 40 g of water was gradually added with stirring. The mixture was stirred at 60° C. for 20 minutes, filtered and washed to obtain a colored spherical powder.

Furthermore, after boiling this colored powder with 100 g of water, filtration, washing with water, then washing with ethanol, and drying at 80°C, a composite pigment exhibiting a clear dark red powder color (product of the present invention 1)
was gotten.

A SEM image of the obtained composite pigment is shown in FIG. This dye concentration was calculated based on the results of carbon analysis using Horiba Carbon Analyzer Model BMrA-110, and was found to be 12.5.
Contains % pigment. In addition, the powder color of the pigment can be measured using a color difference meter (
Hue (H) as a result of measurement with Nippon Juishokusha, Σ80)
= 3.55 R,, aA degree (V) = 2.64, chroma (C
) = 10.05.

In addition, the extensibility (spreadability and slipperiness) on the skin surface, which is a necessary performance for composite pigments as cosmetics, was evaluated in a practical test (10 expert panelists) and found to be good.

Example 4 Spherical powder B obtained in Example 1 1. Og was suspended in 50 g of water, and 0.35 g of natural pigment cochineal (carminic acid, manufactured by Sanei Chemical) dissolved in 40 g of water was gradually added with stirring. The mixture was stirred at 60° C. for 20 minutes, filtered and washed to obtain a colored spherical powder.

Further, this colored powder was boiled with 100 g of water, filtered, washed with water, then washed with ethanol, and dried at 80°C to form a composite pigment (product of the present invention 2) that shows a clear dark red powder color.
)was gotten.

The obtained composite pigment contained 18.0% of the pigment, H=3.50RSV=2.54, and C=10.24.

In addition, the extensibility (spreadability and slipperiness) on the skin surface, which is a necessary performance for composite pigments as cosmetics, was investigated through practical tests and found to be favorable.

Example 5 Spherical powder B obtained in Example 1 1. Og was suspended in 50 g of water, and 0.15 g of Phloxine B (Red No. 104 (1), manufactured by Hassan Kasei) dissolved in 40 g of water was gradually added with stirring. The mixture was stirred at 60° C. for 20 minutes, and then filtered and washed to obtain a colored spherical powder. This spherical powder was placed in an autoclave, and 100 g of water was added to the suspension. The temperature of the suspension was raised to 130° C. over 30 minutes, maintained at that temperature for 1 hour, and then allowed to cool to 70° C. over 30 minutes. Further, when this is washed and dried, a composite pigment (product of the present invention 3) that shows a clear red powder color is obtained.
)was gotten.

The obtained composite pigment contains 10.5% of pigment, H=5.18 R, V=3.80, C=14.30
Met.

In addition, the extensibility (spreadability and slipperiness) on the skin surface, which is a necessary performance for composite pigments as cosmetics, was investigated through practical tests and found to be favorable.

Example 6 Spherical powder B obtained in Example 1 1. Suspend Og in 50 g of water, and add 0 tartrazine (Yellow No. 4, manufactured by Hatsumi Kasei).
．． A solution of 15 g dissolved in 40 g water was gradually added with stirring. The mixture was stirred at 60° C. for 20 minutes, and then filtered and washed to obtain a colored spherical powder.

This flaky powder was placed in an autoclave, and 100 g of water was added to the suspension. The temperature of the suspension was raised to 130° C. over 30 minutes, maintained at that temperature for 1 hour, and then allowed to cool to 70° C. over 30 minutes. When this was further washed and dried, a composite pigment (product 4 of the present invention) exhibiting a clear yellow powder color was obtained.

The obtained composite pigment contains 10.0% of pigment, H=2.61 Y, V=6.46, C=14.50
Met.

In addition, the extensibility (spreadability and slipperiness) on the skin surface, which is a necessary performance for composite pigments as cosmetics, was investigated through practical tests and found to be favorable.

Example 7 Spherical powder B1 obtained in Example 1. Suspend Og in 50g of water and add Brilliant Blue (Blue No. 1, manufactured by Tsumi Kasei)
A solution of 0.15 g in 40 g of water was gradually added with stirring. The mixture was stirred at 60° C. for 20 minutes, and then filtered and washed to obtain a colored spherical powder. This spherical powder was placed in an autoclave, and 100 g of water was added to the suspension. The temperature of the suspension was raised to 130° C. over 30 minutes, maintained at that temperature for 1 hour, and then allowed to cool to 70° C. over 30 minutes. When this was further washed and dried, a composite pigment (product of the present invention 5) exhibiting a clear blue powder color was obtained.

The obtained composite pigment contained 10.0% of the dye, and had H=5.34 B, V=1.24, and C=9.85.

In addition, the extensibility (spreadability and slipperiness) on the skin surface, which is a necessary performance for composite pigments as cosmetics, was investigated through practical tests and found to be favorable.

Comparative Example 1 Made by Nippon Steel ■, average particle size 25.0 μm, specific surface area 1 m
'/g spherical alumina particles (product name AX-25) 1.0
g was suspended in 50 g of ion-exchanged water, and then Phloxine B
A solution of 0.15 g (manufactured by Q8 Kasei) in 40 g of water was gradually added with stirring. The mixture was stirred at 60° C. for 20 minutes, filtered and washed, but the spherical alumina was not dyed and remained white.

Comparative Example 2 Aluminum sulfate 14-18 water (manufactured by Wako Pure Condiments) 6.
7 g and 27.0 g of urea (manufactured by Wako Pure Chemical Industries, Ltd.) were dissolved in 1000 g of ion-exchanged water. When the temperature was maintained at 90° C. with stirring, a white precipitate began to precipitate after 17 minutes, and the reaction was stopped after 80 minutes. The final pH of the suspension was 5.91. After filtering and washing, it was dried at 90° C. for 2 hours to obtain 2.1 g of white powder. Further, it was calcined at 400°C for 2 hours in a nitrogen atmosphere, with a specific surface area of 2.4 rrl/g and an average particle size of 7.6μ.
m spherical alumina powder was obtained.

1.0 g of powder of No. 2 was suspended in 50 g of water, and 0.35 g of natural pigment cochineal (carminic acid, manufactured by Sanei Chemical) dissolved in 4 g of water was gradually added with stirring. The mixture was stirred at 60° C. for 20 minutes, filtered and washed to obtain a pale pink pigment.

The resulting pigment contained only 0.5% dye.

Test Example 1 The products 1 to 5 of the present invention obtained in Examples 3 to 7 were compared with commercially available products in terms of water resistance and solvent resistance. That is,
0.2 g each of the present invention products 1 to 5 obtained in the above examples and the following comparative fields 1 to 3 were added to water, ethanol, or 0.3%
Suspend in saline, shake at 40°C for 1 hour, and filter.
The dye concentration in the filtrate was measured using a spectrophotometer (Shimadzu, UV-200).
) to examine the amount of dye eluted. The results are shown in Table 1 (unit: ppb).

Comparison world 1: Lake pigment R104 (contains 19.4% by weight of Red No. 104-1) Comparison world 2: Lake pigment Y4 (contains 38.6% by weight of Yellow No. 4) Comparison world 3: Lake pigment Bl (Blue 1) Contains 12.5% by weight) No. 1
As is clear from Table 1, the composite pigment of the present invention had excellent water resistance and solvent resistance.

Test Example 2 In order to quantify the extensibility (spreading, sliding) of the powder on the skin surface, the coefficient of friction, which has a high correlation, was measured as a substitute characteristic. That is, the product 3 of the present invention obtained in Example 5
The powder was sandwiched between two aluminum disks, and 10
The friction coefficient of the powder was calculated by applying a load of 0 g in the vertical direction from one side of the disk, rotating the other disk at 300 rpm, and detecting the torque. Mica with good extensibility (
Comparison Field 5) was selected as the target material, and the coefficient of friction was comparatively measured. In addition, non-spherical granular alumina pigments (comparative world 4
) compared with the coefficient of friction. The results are shown in Table 2.

Comparative field 4: Commercially available activated alumina (average particle size 3.4 μm, specific surface area 2
70 go/g, pore volume 0.3 mj)/g > 6.0
Add 54.0 g of water to 0.0 g and stir. 32rnl of IN hydrochloric acid was added and stirred for 1 hour. The final pH was equilibrated at 4.66 at 25°C. It was filtered and dried at 90°C for 2 hours.

Furthermore, it was fired at 400° C. for 2 hours in a nitrogen atmosphere.

The pH of a 5% aqueous suspension of this powder at 25°C is 4.
．． It was 6.

The above fired powder 1. Suspend Og in 50 g of water, and then add Phloxine B (Red No. 104 (1), manufactured by Tsumi Kasei) 0, 1
A solution of 5 g dissolved in 40 g water was gradually added with stirring. The mixture was stirred at 60° C. for 20 minutes, filtered and washed to obtain a colored powder. Furthermore, this colored powder was boiled with 100 g of water. It was filtered, washed with water, washed with ethanol, and dried at 80°C to obtain a granular pigment with an average particle size of 4.5 μl.

Comparative product 5: Commercially available mica (average particle size 15.0μ01) As is clear from Table 2, the composite pigment of the present invention exhibited a low coefficient of friction similar to that of mica.

[Brief explanation of the drawing]

Figure 1 shows the SEM of the composite pigment of the present invention obtained in Example 3.
It is a photograph showing the particle structure by image. More than 10 prisoners

Claims (1)

[Claims] 1. Average particle size 0.1 to 50 μm, specific surface area 30 to 350
A spherical activated alumina support with m^2/g. 2. The spherical activated alumina carrier according to claim 1, which has a pH of 3.0 to 5.0 when made into a suspension. 3. Average particle size 0.1-50μm, specific surface area 1-20m^
2/g of spherical metallic aluminum at pH 7.1 to 11.0.
2. The method for producing a spherical activated alumina carrier according to claim 1, wherein the spherical activated alumina carrier is dried and/or fired after being treated with an alkali. 4. The method for producing a spherical activated alumina carrier according to claim 2, wherein the spherical activated alumina carrier obtained by the method according to claim 3 is further acid-treated and then dried and/or fired. 5. A composite pigment characterized in that an organic dye is embedded in the spherical activated alumina carrier according to claim 1 or 2, and the surface of the spherical activated alumina carrier is hydrothermally treated.