JPS6198770A - Inorganic pigment and its preparation - Google Patents

Abstract

PURPOSE:To obtain an inorganic cobalt blue pigment having excellent weather resistance, and having a hydrated metal oxide coating layer on the surface of particles, by forming a hydrated oxide of a metal selected from Al, Ti, Ce and Zr in an aqueous slurry containing an inorganic cobalt blue pigment. CONSTITUTION:The objective pigment having a hydrated oxide layer of aluminum, titanium, cerium and/or zirconium on the surface of the particle can be prepared by forming a hydrated oxide of one or more kinds of metals selected from aluminum, titanium, cerium and zirconium (preferably cerim or a combination of cerium with other metal) in an aqueous slurry containing an inorganic cobalt blue pigment.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to inorganic pigments, and particularly aims to provide a cobalt blue-based inorganic pigment with improved weather resistance.

(Prior Art) Conventionally, various inorganic pigments are known, and these inorganic pigments are
It has the advantage of superior heat resistance, chemical resistance, weather resistance, etc. compared to organic pigments, and is widely used as a coloring agent for ceramics, paints, plastics, etc.

(The problem that the invention is trying to solve) However,
Co O-nAl, O,-mCr20. (n=0.5~
The cobalt blue type S pigment represented by 3.n=0 to O1 has the advantage of excellent heat resistance and chemical resistance, but has the disadvantage of poor weather resistance. Although the cobalt blue inorganic pigment has a spinel-type crystal structure like other green, brown, and black inorganic pigments.

Compared to the other inorganic pigments mentioned above, there is a difference in performance as described above, and there is a strong demand for improving the weather resistance while taking advantage of the excellent heat resistance and chemical resistance.

(Means for Solving the Problems) In order to solve the above-mentioned drawbacks of the prior art, the inventor of the tree conducted intensive research on cobalt blue-based inorganic pigments, and found that particles of cobalt blue-based inorganic pigments were made from hydrated oxides of specific metals. The present invention was completed based on the finding that a cobalt blue-based inorganic pigment with significantly improved weather resistance while retaining excellent heat resistance and chemical properties can be obtained by coating with a cobalt blue pigment.

That is, the present invention provides a cobalt blue-based inorganic pigment having a hydrous oxide coating layer of at least one metal selected from aluminum, titanium, cerium, and zirconium on the particle surface, and a method for producing the same.

To explain the present invention in more detail, the cobalt blue inorganic pigment used in the present invention is a blue inorganic pigment known per se, and has the general formula 〇o.

* nAJlρ, * mc r, O, (n= 0, 5
~3, 0, m=O~0.5), and has a hue ranging from light blue to deep dark blue depending on the increase or decrease of the alumina content, and the hue can be changed by replacing a part of the aluminum with chromium. The color changes continuously to a green color.

Although such conventional Conoheld Blue-based inorganic pigments have excellent heat resistance and chemical resistance compared to other inorganic pigments, it is known that their weather resistance is uniquely inferior. According to the present invention, the weather resistance is significantly improved by coating particles of such a cobalt blue-based inorganic pigment with a hydrous oxide of a specific metal.

The hydrated oxide (meaning oxide and/or hydroxide) of a specific metal used in the present invention is a hydrated oxide of at least one metal selected from aluminum, titanium, cerium, and zirconium, Such a hydrous oxide t, alone or as a mixture, is preferably used to coat the particle surface of the cobalt blue inorganic pigment in an amount of 0.5 to 10% by weight per 100% by weight of the cobalt blue inorganic pigment. If the amount of the hydrated oxide coating layer is below the lower limit of the above range, the weather resistance of the cobalt blue inorganic pigment will not be sufficiently improved, and if the amount is above the upper limit of the above range, the excellent coloring power of the cobalt blue inorganic pigment will be impaired. There is a risk of damage. In the present invention, a particularly preferred metal is cerium alone or a combination of cerium and other metals.

A preferred method for producing the coated cobalt blue inorganic pigment of the present invention as described above will be described in detail. The cobalt blue inorganic pigment is made into an aqueous slurry using an aqueous medium, preferably water. The aqueous slurry has a pigment content of less than 3% by weight, preferably 5 to 30% by weight. In preparing such an aqueous slurry, a dispersant can be used to disperse inorganic pigment particles as finely and stably as possible in water. Examples of preferred dispersants include sodium hexametaphosphate, sodium pyrophosphate, sodium monophosphate, sodium tetraphosphite, sodium orthophosphate, and soluble phosphates thereof such as potassium, ammonium, and lithium. The amount used is in the range of 0.1 to b amount % per fi pigment.

The hydrous oxides of aluminum, titanium, cerium and zirconium used in the present invention are:

Soluble salts of these metals, such as aluminum sulfate, aluminum chloride, alkyl or allyl aluminum,
Triethyl aluminum, trihexyl aluminum,
Titanium tetrachloride, titanium sulfate, cerium nitrate, cerium chloride, cerium ammonium nitrate, zirconium oxychloride, zirconium tetrachloride, zirconium sulfate, zirconium nitrate, and the like are preferred. To prepare hydrated oxides of metals from these soluble salts, an aqueous solution of these salts is treated with an alkaline agent such as caustic soda, caustic potassium, barium carbonate, potassium carbonate, soda carbonate, potassium bicarbonate, sodium bicarbonate, etc. neutralized, preferably 8.0
This is done by adjusting the pH to 10.5.

The cobalt blue inorganic pigment can be coated with the hydrated oxide of the metal by any method such as simply mixing the aqueous slurry of the cobalt blue inorganic pigment and the hydrated oxide slurry. However, the most preferred method is to generate the above-mentioned hydrated oxide in an aqueous slurry of the above-mentioned cobalt blue-based inorganic pigment, and to coat the cobalt blue-based inorganic pigment simultaneously with the production of the hydrated oxide. To further explain this most preferred method, first of all, the aqueous slurry of the above-mentioned cobalt blue-based inorganic pigment is heated to 30°C to 40°C, preferably 60°C to 90°C.
℃ and the pH of this aqueous slurry is 8.0-1.
Keep it within the range of 0.5. An aqueous solution of one or more of the metal salts and alkaline water are then mixed together with the aqueous slurry of cobalt blue inorganic pigment. At this time, the pH of the mixed moat is within the above range, that is, 8.0.
It is preferable to keep it at 10.5. In this way,
The hydrated metal oxide is generated around the surface of the inorganic pigment and immediately deposits on the particle surface, so that the surface of the inorganic pigment particle is uniformly coated with the hydrated oxide of one or more metals. When coating such inorganic pigment particles, the amount of the hydrous oxide of the metal used is 0.5 to 10% by weight of the inorganic pigment as Amonyu03, T1oi, CeJOs or ZrO.
If the amount is below this range, the objective of improving weather resistance cannot be fully achieved, and if the amount is above the above range, the cobalt blue inorganic pigment will become pale in color. A problem arises in the coloring power of cobalt blue-based inorganic pigments. Furthermore, the metal hydrated oxide forming the coating layer may be a mixture of two or more types, and the mixing ratio may be any ratio, but the optimum combination and ratio may be selected depending on the purpose of improving weather resistance. This is Besse.

After mixing both liquids, the mixture is maintained at a temperature of 60 DEG C. to 90 DEG C. for 0.5 to 5 hours, preferably 1 to 3 hours, to age the resulting coated inorganic pigment.

Through this aging, the inorganic pigment particles and the hydrous oxides of the five metals are integrated, and sufficient weather resistance is exhibited. Thereafter, the coated cobalt blue inorganic pigment of the present invention is obtained by following the conventional methods of filtration, washing with water, drying, and pulverization.

(Function/Effect) Compared to conventional cobalt blue inorganic pigments, the cobalt blue inorganic pigment of the present invention as described above is superior to conventional cobalt blue inorganic pigments when used as a coloring agent for plastics, paints, etc. It exhibits excellent weather resistance that is unimaginable with conventional cobalt blue-based inorganic pigments while maintaining heat resistance, chemical resistance, etc. According to the inventor's detailed research, conventional cobalt blue-based inorganic pigments do not have poor weather resistance by themselves, that is, as a single substance, but especially when used as a coloring agent for plastics, paints, etc. This pigment exhibits a catalytic action that promotes the deterioration of the plastics surrounding it, resulting in various problems such as deterioration of the plastic, fading, chalking, and gloss.This is a drawback of cobalt blue-based inorganic pigments. It was something that was appreciated. In the present invention, the harmful catalytic effect on the surroundings of the conventional cobalt blue inorganic pigment is eliminated by coating the particle surface with a hydrous oxide of a specific metal.

Therefore, the coated cobalt blue inorganic pigment of the present invention is useful as a coloring agent for plastics, paints, and other materials, and can be used for various colored products that have excellent heat resistance, chemical resistance, and even better weather resistance. can give.

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

Example 1 First, a metal salt aqueous solution and an alkaline aqueous solution are prepared.

The aqueous metal salt solution is rated at 20% by weight based on the weight of untreated pigment. Aluminum sulfate (A also (
It was prepared by dissolving 93.6 g of SO+)3.18H,0) in 500 cc of water. Alkaline aqueous solution is NaOH 35g
was prepared by dissolving it in 250CC(7) water.

Next, 500 g of cobalt blue pigment was peptized in one portion of water, 1 g of sodium hexamerinate was added, and peptization was continued until the pigment was sufficiently dispersed.

The aqueous slurry obtained in this way was added with water to make 1 material.
I interpreted it.

This aqueous slurry is heated to a temperature of A and maintained at 80''O.

For pl adjustment, the pH was adjusted to 9 using the NaOH aqueous solution.

After adjusting the pH, the aqueous metal salt solution was added dropwise together with the aqueous alkaline solution while maintaining the PR range.

In this way, a hydrous metal oxide is deposited on the surface of the pigment, and coating treatment is performed. After dropping the metal salt aqueous solution, ripening was carried out while maintaining the temperature at 80°C. After aging for 1 hour, the aqueous slurry containing the surface-coated cobalt blue pigment was washed with water, filtered, dried, and pulverized to obtain the alumina-coated cobalt blue pigment of the present invention.

-(Example 2 Titanyl sulfate (
TiO3O4.2H20) was used. A titanium oxide coated book was obtained by weighing 36.8 g of T i O2, which corresponds to 3% by weight of the pigment, against the weight of 500 g of untreated pigment, and performing coating treatment in the same manner as in Example 1. A cobalt blue pigment of the invention was obtained.

Example 3 Instead of aluminum sulfate in Example 1, cerium nitrate (Ce (NO), -6H,0) was used as Ce, O, and 39.7 g of the amount corresponding to 3% by weight of the pigment was weighed and carried out. Coating treatment was performed in the same manner as in Example 1 to obtain a cobalt blue pigment of the present invention coated with cerium oxide.

Example 4 The two types of aluminum sulfate and titanyl sulfate used in Examples 1 and 2 were converted into At, O, TiO, each in an amount of 1.5% by weight relative to the pigment, in a total amount of 3% by weight, i.e. 46.8 g of aluminum f&acid and 18.4 g of titanyl sulfate were weighed and coated in the same manner as in Example 1 to obtain the cobalt blue pigment of the present invention coated with alumina and titanium butyride.

Example 5 Two types of aluminum sulfate and cerium nitrate used in Examples 1 and 3 were mixed with A 1.0. , Ceyu0. Weighed 46.8 g of aluminum sulfate and 19.9 g of cerium nitrate, each weighing 1.5% by weight of the pigment and 3% by weight in total, and coated with the same method as in Example 1 to coat the alumina. A cobalt blue pigment of the present invention coated with cerium oxide was obtained.

Example 6 The two types of titanyl sulfate and cerium nitrate used in Examples 2 and 3 were replaced with TiO□, Ce, 0. As a result, each pigment has a pigment content of 1.5%, for a total of 111%, which is 3% by weight.
Namely, 18.4 g of titanyl sulfate, 19.0 g of cerium nitrate.
9 g was weighed and coated in the same manner as in Example 1 to obtain the cobalt blue pigment of the present invention coated with titanium oxide and cerium butyride.

Example 7 Example 1. The three types of aluminum sulfate, titanyl sulfate, and cerium nitrate used in Examples 2 and 3 were mixed with AI, 0.
, T i O, , ce2o7 toshiteso, respectively, with pigment 0.
75% by weight, 0.75% by weight, 1.5% by weight each, a total of 3% by weight, that is, aluminum sulfate23
, 4 g + titanyl sulfate 9.2 g, cerium nitrate 19.
9 g was weighed and coated in the same manner as in Example 1 to obtain the cobalt blue pigment of the present invention coated with alumina, titanium oxide, and cerium oxide.

Example 8 Two types of aluminum sulfate and zirconium oxychloride (ZrOCl2.8H20) used in Example 1 were mixed with AI,
0. Weighed 1.5% by weight of each pigment as ZrO and ZrO, a total of 3% by weight, that is, 46.8 g of aluminum sulfate and 20 g of zirconium oxychloride.
Coating treatment was carried out in the same manner as in Example 1 to obtain a cobalt blue pigment of the present invention coated with alumina and zirconia.

Comparative Example 1 Untreated cobalt blue pigment used in Examples 1 to 8 Comparative Example 2 A cobalt blue pigment coated with silica, which is often used as a surface treatment agent for titanium oxide. This coated pigment was prepared as follows.

500 g of cobalt blue pigment is peptized in IQ water, and 1 g of sodium hexametaphosphate is added to further thoroughly disperse it. This aqueous slurry is diluted with water to make 4 sentences. The resulting aqueous slurry was heated to y1 temperature, raised to ao'c, and the pH was adjusted to 9.5. No. 3 silicic acid (Si02
29%) Calculate water solubility as 5iO1 for pigment 3
After weighing the amount in weight%, this water-soluble Iα is diluted with water,
The 5iOL content should be around 5% by weight. The silicic acid aqueous solution thus prepared is slowly dropped onto the slurry together with the diluted sulfuric acid aqueous solution while maintaining the above pH. After dropping the silicic acid aqueous solution, the pH was lowered to 7 and the mixture was aged for 1 hour. This aqueous slurry was washed with water, filtered, dried and ground to obtain a cobalt blue pigment coated with silica.

Test Example A melamine algide paint (PI (R40)) was prepared using the pigments obtained in the above Examples and Comparative Examples, and the paint was sprayed on a metal plate coated with carbon arc light in a shine-type tetherometer. The weather resistance was tested. The results are summarized in Table 1. According to Table 1, the cobalt blue pigment obtained by the present invention has improved weather resistance compared to the untreated pigment. Cerium has a great effect on improving weather resistance. Better results are obtained by treating with two or three metals than with a single metal. Here too, it is desirable to treat with cerium as the main ingredient. Treatment with zirconia also improves weather resistance.It also has the advantage of being more glossy when painted compared to pigments treated with other metals.

The pigment treated with silica of Comparative Example 2 did not have a glossy appearance when painted, and its weather resistance was also worse than that of the untreated pigment.

＼, (Hereinafter, the margin) -n knee 1-'' Beni coating treatment Coating weight Gloss Resistance to scratching Tsumugi Mushimi 1 AP Retention rate Soil Zagging property example Yu
3 1.85 73.8 2 Example 2 Ti 3
5.20 78.7 3 Example 3
Ce3 2. ro80.2 4m
AI, Ti Al 1.5, Ti 1.5
2.30 81.8 3 Example 5 Ce, A
I cell, 5, Al 1.5 1.95
79.7 4 Example 6 Ce, Ti
(:el, 5, Ti 1.5 2.40
84.4 5 Example 7 Ca, Ti, A
I C, e 1.5, Ti O, 7, AI O, 72
,0582,55 Example 8 Zr, AI
Zr1.5. AIl, 5 2.15 81.7
4 Comparative Example U - -3,
9570,42 Comparative example name Si
3 4.45 58.3 1*
Weatherometer 800 hrs (7m choking resistance was evaluated after 1.000 hrs.) * Gloss: 60° specular reflection Chalking is the most severe, and 5 indicates no chalking.) Patent applicant: Dainichiseika Kagyo Co., Ltd. (1 person)

Claims (4)

[Claims] (1) A cobalt blue-based inorganic pigment having a hydrated oxide coating layer of at least one metal selected from aluminum, titanium, cerium, and zirconium on the particle surface. (2) The cobalt blue-based inorganic pigment according to claim (1), wherein the metal is cerium or a combination of cerium and another metal. (3) A cobalt blue type having a coating layer characterized by producing a hydrous oxide of at least one metal selected from aluminum, titanium, cerium, and zirconium in an aqueous slurry containing a cobalt blue type inorganic pigment. Method for producing inorganic pigments. (4) The manufacturing method according to claim (3), wherein the metal is cerium or a combination of cerium and another metal.