JPS61179263A - Pigment and production thereof - Google Patents

Abstract

PURPOSE:To obtain a pigment which has excellent resistance to water, solvents, oxidation and light and safety and gives a clear color, by bringing a porous alumina contg. an anion into contact with an org. dye soln. and then sealing pores. CONSTITUTION:A porous alumina contg. 0.1mol/kg or more of an anion is brought into contact with an org. dye soln. to enclose a dye in pores, and the pores contg. the dye are sealed. Any of porous alumina contg. 0.1mol/kg or more of an anion and having pores capable of enclosing an org. dye molecule therein may be used, but one having a specific surface area of 10m<2>/g or above is preferred to enclose the dye molecule therein. As the anion, chloride and sulfate ions are particularly preferred.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a novel pigment and a method for producing the same, and more specifically, the present invention relates to a novel pigment and a method for producing the same, and more particularly, the present invention relates to a novel pigment and a method for producing the same. After that, the hole is sealed L7.
This is a book about a new pigment that has excellent water resistance, solvent resistance, oxidation resistance, light resistance, and safety, and provides a vivid color tone, and a method for producing the same.

[Conventional technology]

Although organic pigments are superior to inorganic pigments in terms of color clarity and variety, they are often inferior in stability, such as water resistance, solvent resistance, and light resistance. On the other hand, while many inorganic pigments have excellent stability, they have drawbacks such as generally dull color tone and limited color types.

Many attempts have been made to combine organic and inorganic pigments in order to take advantage of their respective strengths and compensate for their weaknesses, thereby obtaining pigments that have the excellent properties of both.

For example, a method of coating the surface of titanium oxide, barium sulfate, etc. with an organic dye and making it insolubilized to improve hiding power and weather resistance (JP-A-56-106965, JP-A-55-137)
No. 14, No. 56-99262, No. 56-141362
A method for obtaining pigments by embedding organic pigments in clay minerals, clay minerals, and other porous powders by ion exchange or adsorption (Japanese Patent Laid-Open No. 53-92842)
No. 53-92843, No. 51-63948, No. 49-90931, No. 55-133462, No. 56
-103105 etc.) were known.

[Problem that the invention seeks to solve]

However, in the method of coating inorganic powder with organic pigments, the coated material is likely to peel off, and since the organic pigments are exposed on the surface, water resistance, oil resistance, weather resistance, etc. There are limits to the improvement, and the drawbacks of organic pigments could not be fully covered.

On the other hand, methods that confine organic dyes within inorganic materials often sacrifice the clarity of the organic dyes, and if the confinement is incomplete, improvements in water resistance, oil resistance, weather resistance, etc. It is often difficult and f? For example, in JP-A-53-2003, powder of silica, arsunosilicate, etc. is coated on the inner core material of the frames and sintered to form a porous powder, which encapsulates an organic pigment. In the method typified by No. 92842, the pores are formed by voids between the coated powders, so the pores are coarse and the adsorption power is weak. However, not only is there little improvement in water resistance and oil resistance, but also a decrease in the brightness and vividness of the color tone is inevitable due to multiple light scattering and absorption by the outer shell material. Furthermore, in the method of ion-exchange adsorption of dyes such as Rhodamine B into ion-exchangeable clay minerals to develop color, as disclosed in JP-A No. 56-103105, the @ tone decreases due to the absorption and scattering of light by the clay. As mentioned above, inorganic porous powders have been used in conventional techniques to obtain pigments that have both the excellent properties of organic pigments and inorganic pigments by making use of their respective strengths and compensating for their weaknesses. The method of trapping brightly colored organic pigments in the body is water resistant,
Although it somewhat improves physical properties such as oil resistance, it often impairs the purity of the original color of the dye.

In order to achieve sufficient water and oil resistance, it is essential to prevent water and oil from penetrating into the dyes adsorbed in the pores of porous powder. It is considered effective to seal the hole with a material that is resistant to water and oil.

In addition, the cause of color tone deterioration is due to light scattering due to the optical non-uniformity of porous powder and light absorption due to colored impurities contained in porous powder. It is important that the powder has uniform optical properties and absorbs little visible light. Similar properties are also required for the substance that seals the pores after dye adsorption.

[Means for solving problems]

Under these circumstances, the present inventor conducted research and was able to produce a pigment that has an extremely clear color, excellent coloring power, and is stable.
．． The present invention provides a pigment in which an organic dye is encapsulated in porous alumina containing 1 mol/Ky or more, and the pores are sealed.

In the pigment of the present invention, the porous alumina has an anion of 0.
．． Any material may be used as long as it contains lrnol/K9 or more, encapsulates organic dye molecules, and has vine pores, but in order to encapsulate a large amount of dye, it is particularly preferable to have a specific surface area of 10 m"/f or more. Examples of anions contained in the porous argus include chloride ions, sulfate ions, nitrate ions, phosphate ions, silicate ions, borate ions,
Examples include mineral acid ions such as titanate ions, organic acid ions such as acetate ions, oxalate ions, formate ions, and citrate ions, with chloride ions and sulfate ions being particularly preferred.

According to the method of the present invention, the pigment of the present invention has anions of O, l
mol/KI? It is produced by bringing the porous aluminum contained above into contact with an organic dye solution to embed the dye in the pores, and then sealing the pores.

The anion-containing porous Al-Ti is produced, for example, by the following method.

■ Alξnium hydrochloride, sulfate, nitrate, acetate,
An aqueous solution of an acidic aluminum salt or a hydrated salt thereof such as oxalate or a hydrated salt thereof whose 10% aqueous solution has a pH of 5.5 or less is completely neutralized with a base such as aqueous ammonia or caustic alkali. A method of forming a hydrate gel, then drying and baking it.

■ Alkaline aluminate salts such as sodium aluminate and potassium aluminate are neutralized with acids such as sulfuric acid, nitric acid, hydrochloric acid, oxalic acid, formic acid, and citric acid to form an alumina hydrate gel, which is then dried and calcined. how to.

■ A method in which alumina hydrate is fired to make it porous and then treated with acid to add anions.

■ A method of adding anions to porous alumina such as hydraulic alumina by acid treatment. ■ A method of thermally decomposing aluminum salts containing volatile anions in air.

Among these methods, the anion-containing porous aluminum obtained by method (1) is particularly preferable as a raw material for producing the pigment of the present invention.

Therefore, the method for producing anion-containing porous alumina using the neutralization method (2) will be described in detail below.

When neutralizing an aluminum salt or its hydrated salt with a base, uniform mixing is important, and both are used as an aqueous solution or a basic gas is blown into the aluminum salt aqueous solution.

If the concentration of aluminum salt is 0.5 to 5 wt% in terms of albina at the end of neutralization, it is easy to remove the aluminum salt. A gel is formed upon completion of neutralization, and in this respect it is preferable for the pH to be between 3 and 9 in terms of yield. In the case of a two-component mixing method, both solutions can be mixed by adding either solution to the other, or both solutions can be added at the same time, but it is essential to stir well to ensure uniformity during mixing. It is.

In addition, after neutralization, the gel produced for 10 minutes to complete the reaction was
It is desirable to perform A-Song for one day. After aging, wash the glue with approximately the same amount of water and remove the supernatant liquid by decanting. Washing may be repeated several times to remove cations such as sodium and potassium. This washing is not necessarily necessary when neutralized by alkali, such as ammonia or amine, which escapes from the dal during ignition.

After washing, water and dal are separated by centrifugal dehydration or filtration. This dal should be heated to 250℃ or less, preferably 100 to 20℃.
Dry at 0° C. for 15 minutes to 30 hours until a constant weight is obtained to obtain a xerogel of alumina hydrate.

-l 1- This xerogel is pulverized to the required particle size using a grinding machine, an air chute bar, a sand mill, a l-mill, or the like. Powder particle size is 0.01 tm to 1 ml
However, in consideration of the coloring power and feel of the pigment, it is preferably 0.1 to 20 μm. The pulverization can also be performed after the xerogel is calcined and dehydrated.

Furthermore, when a freeze-drying method is used to dry the gel, pulverization can be omitted.

The xerogel of alumina hydrate obtained as described above is calcined at 250 to 800°C, preferably 350 to 600°C for 30 minutes to 10 hours to form an amorphous or alumina hydrate such as ρ alumina. Porous alumina containing no alumina is used. Firing is performed in a gas stream of air, nitrogen, carbon dioxide, argon, or the like. Also, it is also good to do this under rM pressure.

If necessary, the calcined alumina is pulverized by the method described above to obtain powdered porous alumina.

The porous alumina thus obtained has active micropores and is therefore very convenient for encapsulating dyes. In addition, the anions of raw material aluminum contained in porous alumina have the effect of increasing the inclusion of pigments and increasing the clarity.

For this reason, excessive heat treatment conditions are not preferred during firing.If necessary, not only the anions of the raw material salt but also chlorine ions, sulfuric acid, nitric acid, phosphoric acid, silicic acid, etc.
Good results can also be obtained by adding salts having anionic groups such as boric acid and titanic acid singly or in combination.

The dyes to be embedded in the pores of porous alumina include acid dyes, basic dyes, natural dyes, oil-soluble dyes, vat dyes, etc. Coloring with any dye is possible, but acid dyes Somoto is preferable.

Acid dyes include Red No. 2, Red No. 3, Red No. 102,
Red No. 104-1, Red No. 105-1, Red No. 106,
Yellow No. 4, Yellow No. 5, Green No. 3, Blue No. 1, Blue No. 2,
Red No. 227, Red No. 230-1, Red No. 230-2,
Red No. 231, Red No. 232, Daidai No. 205, Daidai No. 207, Yellow No. 202-1, Yellow 202-2
No., Yellow No. 203, Green No. 201, Green No. 204, Green No. 205, Red No. 202, Blue No. 205, Brown 201
No., Red No. 410, Red No. 502, Red No. 503, Red No. 504, Red No. 506, Orange No. 402, Yellow 4
No. 02, Yellow No. 403-1, Yellow No. 406, Yellow No. 407
No. 402, green No. 402, purple No. 401, black No. 401, etc., and if necessary, these can be mixed and used as appropriate.

Basic dyes include Red No. 213 and Red No. 214, as well as Auramine, Brilliant Yellow, Basic Yellow 14, Basic Orange 2, Basic Orange 22, Basic Red 12, and Brilliant Red 14.
, Basic Red 14, Basic Red 18, Basic Red 34, Basic Red 37, Crystal Violet 3, Crystal Violet 7, Crystal Violet 10, Crystal Violet 14, Paysic Blue 1, Paysik Blue 5, Paysic Blue 21, Pay Thick Green 4 and the like can be mentioned, and one type or a mixture of two or more of these can be used.

Natural pigments include alizarin, calsamine, β-carotene, chlorophyll, brasilin, bixin, norbixin, crocin, carcinol, safrole yellow, ethdianin, shisonin, delphicin, cacao pigment, carminic acid, laccaic acid, betanin, curcumin,
These include caramel, Monascorubin, etc., and can 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.

In the coloring step, the porous alumina prepared as described above is coated with 0.001 to 10 wt% of the dye, preferably 0.001 to 10 wt%. O1
This is carried out by contacting and reacting with a ~3 wt% solution.

As the dye solution, an aqueous solution is preferable in the case of an acidic dye, a basic dye, or a natural dye, and an organic solution is preferable in the case of an oil-soluble dye, but a mixed solution of water and an organic solvent is also used in some cases.

For vat dyes, an aqueous solution of the reduced product is used.

A surfactant, inorganic salts, etc. may be added to the dye solution in order to improve the dyeing property, depending on the necessity.

The contact and action operation of the porous alumina and the dye solution can be carried out by dipping, dropwise mixing, and fluidized bed mixing.The contact and action time is 1 to 60 minutes, and the temperature of the dye solution is 80°C.
It is preferable to keep it below ℃. When the pigment is encapsulated in alumina at a weight ratio of 0, olr/toalumina or more, preferably 0.05 to 1.02/2.alumina, by this contact and action operation, it has preferable properties when used as a pigment.

In order to close the pores of the porous alumina containing the dye, it is subjected to hydrothermal treatment. Among porous aluminas, aluminas having forms such as amorphous alumina, ρ alumina, and hydraulic alumina easily become alumina hydrate through a hydrothermal reaction and undergo volumetric expansion. For this reason, when porous alumina containing a dye encapsulated in its pores is subjected to hydrothermal treatment, the pores are closed due to volumetric expansion, and elution of the dye can be prevented.

The hydrothermal reaction of porous alumina occurs when treated with hot water at a temperature of 70 to 180°C, but when pressurized steam at a temperature of 100 to 180°C is used, the pore sealing becomes more optical. However, some pigments change color when the temperature exceeds 150°C, so care must be taken.The higher the temperature, the shorter the time required for sealing, and it may take 5 minutes to 5 hours depending on the temperature. be.

After hydrothermal treatment, it is filtered, and if necessary, the solvent is replaced and dried. By repeating this process several times, the sealing properties become very good, but can this process be done with aluminum acetate, aluminum hydroxychloride, aluminum chloride, etc.? Even more excellent pore sealing properties are exhibited when the process is carried out in the coexistence of a solution such as aluminum chloride.

In addition to the above aluminum salts, other aluminum salts, barium salts, zolconium salts, silicates, borates,
Group 11a, ub group, such as titanates and molybdates,
Similar good results can be obtained by hydrothermal treatment in the coexistence of water-soluble salts of the Ib group, Ma group, IIb group, and Vb group.

When there are many anions such as chloride ions and sulfate ions in porous alumina, dye embedding is likely to occur and the colors are bright and vibrant, but on the other hand, the activity for the pore sealing process decreases7, making it more severe than when there are few anions. L7 processing is required.

In the sealing treatment using the aqueous solutions of various salts,
In addition to hydrothermal treatment, it is also possible to simply introduce alumina containing a dye into a treatment solution, stir it, wash it, and filter it, or bring it into contact with a fluidized bed.

The above-described pore sealing treatment not only improves water resistance and oil resistance, but also makes the color of the powder more vivid than before the treatment.

After the pore sealing treatment, the powder is finally washed, filtered, and dried at 120°C or lower. Powder with good physical properties can be obtained by washing with an organic solvent such as acetone or ethanol to speed up the drying of the filtration process and prevent secondary agglomeration.

Furthermore, in order to adapt the surface properties of the alumina pigment obtained in this way to various uses, surfactants, alkyds, -lyesters, etc. Liamid etc.? It is possible to treat with a reamer.

[For production]

The pigment of the present invention obtained as described above uses porous alumina containing anion of O,l moJ / K9 or more as a phase, and therefore has excellent color clarity and storage capacity of the organic pigment. This is a book that has been enhanced. Furthermore, the pores can be easily sealed after dye adsorption by hydrothermal treatment, etc., and the pores are extremely strong, resulting in excellent stability in terms of water resistance, oil resistance, weather resistance, etc.

〔effect〕

As described above, the pigment of the present invention has stability such as water resistance, oil resistance, and weather resistance, and provides a clear color tone.
If this is used in various applications, conventional organic pigments have bright colors and a wide variety of types, but their use has been limited due to lack of stability, such as cosmetics for make azzo, food packaging materials, etc. , extremely useful in the field of toy materials, etc.

〔Example〕

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

Example 1 Reagent-grade aluminum chloride hexahydrate 820f was added to 7380
9 of water, and while vigorously stirring with a high-speed homomixer, 537 tons of 28% aqueous ammonia was gradually added to neutralize the solution. Gelation progressed with neutralization. The pH before neutralization was 2.36, and the pH at the end of neutralization was 6.98. This dal was allowed to stand overnight at room temperature and centrifuged, and the 5300F supernatant water was removed and the same amount of ion-exchanged water was added. This was stirred with a homomixer and centrifuged again to remove supernatant water.

The resulting translucent white gel was dried at 125°C for 5 hours.
2. Further, after drying at 100° C. for 17 hours, the mixture was coarsely ground in a mortar so that the total amount passed through a 0.25i11 sieve. Through the above operations, 318f white powder was obtained. Out of this, 303f was passed through Nippon Pneumatic Suit Q-Sonic Sheet Mill for pulverization, and 234f of white fine powder was
I got it. This is called powder A.

Powder A 227 was heated in a Matsufuru furnace at 400°C for 3 hours L7, and the particle size distribution of the resulting 118f white fine powder was measured: 9% below 4ttm, 7% above 10μm, median particle size 7. It was .3 μm. X@diffraction)
The nine turns were almost amorphous as a whole, except for a broad peak of ρ-amina. Also, according to elemental analysis, chlorine ions were present at 1.00 mol/min, and the specific surface area determined from BET adsorption of nitrogen was 183 m.
/f. This is called powder B.

Powder B552 was added to a 3% solution of Red No. 104-1, a food additive class I color (1400), stirred at 45°C for 15 minutes, centrifuged, and the supernatant was removed by decantation.

A part of the precipitate was sampled, filtered and washed, replaced with acetone, and then dried at 40°C overnight to obtain 1.4 t of red powder. This is referred to as Comparative Example 1.

On the other hand, add 1000 g of ion-exchanged water to the remaining precipitate and
After boiling for 0 minutes, it was filtered and washed, and finally, the adhering water was replaced with acetone, and it was left to dry at 40° C. overnight.

A bright red powder was obtained by the above operations. The pigment concentration in this was measured using a Horiba Carbon Analyzer EMIA-
Calculated based on the results of carbon analysis using Type 110,
It was 15.4 wt%. Table 1 shows the results of a comparison of color tone, water resistance, and solvent resistance between this and the corresponding commercially available lake pigment R104 (containing 19.4 wt% of Red No. 104-1; Comparative Example 2).

Table 1 In Table 1, the L% a and b values were measured using an 8M color computer (manufactured by Suga Test Machinery) SM-3. The amount of elution is determined by adding 0.2 t of sample to 30 g of water, two types of aqueous solutions with different pH values, or a water/acetone mixed solution, stirring at 40°C for 1 hour, filtering, and measuring the dye concentration in the filtrate using spectroscopic analysis. Quantification was done photometrically. In addition, it was visually confirmed that the dissolution property of Comparative Example 1 was significantly higher than that of Comparative Example 2.

When X-ray diffraction was measured on the obtained pigment of the present invention,
Broad diffraction lines of pseudo-boehmite were observed, indicating that alumina was partially hydrolyzed. Further, as a result of observation using a scanning electron microscope, growth of fine crystals was observed on the particle surface. On the other hand, Comparative Example 1 had exactly the same X-ray diffraction (Q-turn) as before staining, and no change before and after staining was observed under electron microscopy.

Example 2 Alumina powder B 35f obtained in Example 1 was added to 1,400 ml of a 3% aqueous solution of yellow No. 4 and heated at 45°C for 15 min.
Stained for minutes. The dyed alumina was filtered out using a filter paper, 1000 ml of ion-exchanged water was added thereto, and the mixture was boiled for 20 minutes.

After filtration and washing with water, the remaining liquid was replaced with acetone and dried at 40° C. overnight to obtain a bright yellow powder. Carbon analysis showed that it contained 4.7 wt% dye.

This was mixed with a commercially available lake pigment (yellow No. 4 at 38.6w).
The results are shown in Table 2 when compared with t% content). (Example 2a) A clear powder was obtained by coloring with Blue No. 1 in exactly the same manner. From the results of carbon analysis, this powder was 11.8 wt%
It was found that it contains pigments. When this was compared with a corresponding commercially available lake pigment (containing 12.5% Blue No. 1), the results were as shown in Table 3. (Example 2b) Table 2 Table 3 In both Examples 2a and 2b, the dissolution properties of preparative samples that were not subjected to boiling treatment after dyeing were similar to those of the corresponding commercially available lake pigment, regardless of which solvent system was used. It was clearly large and its stability was inferior. Furthermore, the results of X-ray diffraction and electron microscopic observation before and after boiling were the same as those in Example 1.

-31-Example 3 8 tons of fine powder produced in exactly the same manner as Nine Powder A obtained in Example 1 was fired at various temperatures and times, and 2 tons were taken and dyed with red No. 104-1 solution. did.

The concentration of the solution was 0.095% to 3.0% and the bath ratio was 1.
/401 Staining was carried out at a temperature of 40°C for 1 hour.

Furthermore, these were treated with boiling water for 20 minutes in the same manner as in Example 1, filtered, replaced with acetone, and dried at 40° C. for 1 hour. The dye concentration in the obtained pigment powder was measured by carbon analysis and was as shown in Table 4. All of these are
It exhibited a vivid red color depending on the pigment concentration. Further, for some of them, the specific surface area of the original material before dyeing and the elution test with a water/acetone mixed solution were conducted in the same manner as in Example 1. The results are also shown in Table 4.

Ct ion concentration in alumina before dyeing is sample AI%
1.20.0, 84.0 for each of 5.9.11
．． 60 and 0.26 mol/Kf.

Table 4 Example 4 Reagent-grade aluminum chloride hexahydrate 3002 at 270O
f water to obtain a solution with pH 2.36. At 24°C, a 28% ammonia aqueous solution 101.3
f was added gradually. During this time, use a homomixer for 10'
Homogenization was performed by stirring vigorously at rpm. The pH of the resulting white gel slurry was 5.32.

The resulting dal 2667f was centrifuged and supernatant portion 1
After removing 565t by decantation, ion exchange water 15002 was added and homogenized using a homogenizer. The supernatant portion was removed by centrifugal sedimentation again, the remaining portion was homogenized by adding 250 tons of ion-exchanged water, and freeze-dried.

As a result, a white powder of JJ852 was obtained. Electron microscopic observation revealed that this material consisted of crushed particles having a diameter of approximately 3 to 30 μm. This is 4001:
After firing for 3 hours in an electric furnace, an amorphous alumina was obtained as seen by X-rays. This is 1, 9
It contained 6 mol/Kl (J ions).

This powder 15f was dyed in the same manner as in Example 2, washed as before, and then dried.

Of these, 2 tons were sealed in the same manner as in Example 2, washed and dried. The obtained red powder contains 10.75 pigments, and the color tone is (k=29.68, a=58.42, b=x
4. s4) had a clear red color. Also,
In the elution test, the water resistance of Example 3 was demonstrated.

The above red powder before sealing contains 11.82 wt% of pigment, k = 29.80, a = 57.09, b = 14.2
1, but it had poorer water resistance and oil resistance than commercially available lake pigments.

This powder was subjected to hot water treatment and silica treatment for sealing, respectively. That is, hot water treatment is performed on unsealed powder 2. The suspension was prepared by placing Of in an autoclave and adding 100 tons of water, and the temperature was raised to 180° C. in 30 minutes, held for 1 to 1 hour, and then allowed to cool to 70° C. in 30 minutes. The pigment content of the treated powder obtained by washing and drying this was 11.54 w.
t%, :[,==18,81. lk=58, 12, b
=12.31? Was there oX? Formation of some pseudo-boehmite was observed by fM diffraction. It was confirmed in an elution test using water and acetone that no dye was eluted.

On the other hand, silica treatment was carried out as follows. No. 3 silica (Sing)
t 30.2%, Nano; 10.0%) 2? was diluted to 200-200 with water, and the resulting solution with a pH of 11.0 was neutralized with hydrochloric acid to a pH of 6.8. Immediately, 2.02 of the unsealed powder was added to this colorless transparent liquid, and the mixture was left to stand for 20 hours while stirring. This was washed with filtered water, the adhering water was replaced with acetone, and dried to obtain a bright red powder.

This product did not dissolve in water or acetone, and exhibited excellent water resistance and oil resistance comparable to those of Example 1.

Example 5 Aluminum chloride hexahydrate 409 was dissolved in 260 tons of water and gradually neutralized with 281 ammonia water while stirring at room temperature. The pH after neutralization was 9.0. The obtained white glue was allowed to stand for 3 hours, then centrifuged, the supernatant liquid was removed by decantation, and the same amount of water was added and washed with stirring. After repeating the washing process three times, it was dried at 130°C for 3 hours. The dried product was crushed in a mortar and calcined at 400° C. for 3 hours to obtain a white powder. This one contains chlorine ions at 0.85 ma
It included t/Kp. 2f of this was dyed and sealed with Red No. 104-1 in the same manner as in Example 1, washed and dried to obtain a bright red powder. The pigment content of this product is 12. l l wt%, J, = 28.15,
a=49.94 and b=13.52, indicating good water resistance and oil resistance.

Example 6 Anhydrous aluminum sulfate 30F was dissolved in 2701 water,
A solution with a pH of 2.89 was prepared. Stir this and Hikogara28
% aqueous ammonia until the pH reached 5.11, and the resulting pale white dal was washed, dried, crushed, and calcined in the same manner as in Example 5 by centrifugal sedimentation and decantation.

The obtained powder has a light gray color and contains 0.63 sulfate ions.
It included moJ/K9. This was dyed with red No. 104-J in the same manner as in Example 5, and the pores were sealed to obtain a red powder.

The pigment content of this powder is 12.11 wt%, L=35.
72, a=53.23, b=8.78"t', and had good water resistance and oil resistance.

-39 Example 7 Alumina for thin l-chromatography (specific surface area 70
FM”/ts Pore diameter 15OA, pore volume 0.
2 d/f, chloride ion content 0.28 moj/K
y) Lot of 3 pieces of red No. 104-1 solution 400
The mixture was stirred at 40° C. for 10 minutes, then washed and dried. This was divided into two parts, one part was left as is, and the other part was boiled in hot water for 15 minutes, washed, and dried to obtain red powders for each part.

When the elution properties of these in water and acetone were investigated in the same manner as in Example 1, the dye was significantly eluted in the case of the adsorption treatment only, but no elution was observed in the case of the hot water treatment, which was the same as in Example 1. showed similar levels.

The pigment content of the hot water treated product is 3.65wt5, L=39
．． 34, a=54.42, b=6.55. On the other hand, when the dye solution was dyed with sulfuric acid, the pH of which had been set in advance to be 5, and then boiled, washed, and dried in the same way, the pigment content in the powder was 5.68 wt%, L = 35.
．． 75, a=58.12, b=12.31, which showed improved sharpness.

Example 8 2Of aluminum chloride hexahydrate was heated at 130°C in an evaporating dish.
After drying for 3 hours and subsequently baking at 40°C for 3 hours, the mixture was ground in a mortar to obtain a white powder. This material is X-ray amorphous and has a chloride ion content of 0.63 moJ/9.
Met.

When this white powder was dyed, boiled, washed, and dried with Red No. 104-1 as in Example 6, water resistance and
A bright red powder with oil resistance was obtained. The pigment content of this product is 11.19 wt%, L=31.12, a=5
8.42, b=14.54.

Comparative Example 3 2 tons of fine powder produced in exactly the same manner as Powder B obtained in Example I was washed with 100% ion-exchanged water, then decanted and filtered, and this operation was repeated twice.

Further, water was added to the suspension to make it 200-200, and the pH of the suspension was adjusted to 8 with aqueous ammonia.

This was filtered and the same pHy4 production procedure was performed again.

After replacing the filtrate with 7 tons, it was dried and heated at 400°C for 30 minutes.
After 0 minutes of formation, alumina powder was obtained.

According to the X-ray diffraction and BET measurement results, this alumina grain is almost amorphous and has a specific surface of PR169m"/
It had t.

One ton of this fine powder was taken and dyed and post-treated in the same manner as in Example 3 using a 1% solution of Red No. 104-1.

Although the obtained powder was slightly colored, it could not be used as a pigment.

Comparative Example 4 Specific surface area 120 yH”/t, pore volume 0,
Porous alumina with a particle size of 40 μm was dyed and post-treated in the same manner as in Example 7, but the dyeability was poor, and carbon analysis showed that only 0.79 vt% of dye was retained. It was.

Note that the anion u related to the present invention contained in this porous alumina was less than 0.01 mol/Kl.

that's all

Claims (1)

[Scope of Claims] 1. A pigment characterized in that an organic dye is encapsulated in porous alumina containing 0.1 mol/kg or more of anions, and the pores are sealed. 2. A method for producing a pigment, which comprises bringing an organic dye solution into contact with porous alumina containing anion in an amount of 0.1 mol/kg or more to embed the dye in the pores, and then sealing the pores. 3. Porous alumina containing 0.1 mol/kg or more of anions is prepared by neutralizing an aqueous solution of an acidic aluminum salt or a hydrated salt thereof with a base so that the pH of its 10% aqueous solution is 5.5 or less. 3. The method for producing a pigment according to claim 2, wherein the pigment is formed into a pigment gel, which is then dried and fired.