JPH038728A - Production of green pigment of multi-component oxide of fine granule - Google Patents

Abstract

PURPOSE:To obtain pigment useful as coloring agent having excellent transparency and dispersibility by adding aqueous solution of alkali to mixed aqueous solution of Ni salt or Co salt, etc., containing hydrogen peroxide or peroxo acid, etc., and burning resultant coprecipitated substance. CONSTITUTION:A Ti compound and Ni salt, Co salt or Zn salt are dissolved in water. Then, at least one of hydrogen peroxide, peroxo acid (peroxosulfuric acid, peroxonitric acid, peroxocarbonic acid, peroxoboric acid and peroxophosphoric acid) and peroxo acid salt is added to said mixed aqueous solution. Next, aqueous solution of alkali is added to resultant solution and coprecipitated substance is generated. Thus, said coprecipitated substance is burned to afford the aimed pigment.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for producing a fine particle composite oxide green pigment with excellent transparency and dispersibility, which is useful as a coloring agent for paints, synthetic resins, ceramics, etc. Regarding.

[Prior Art] Complex oxide green pigments are widely known as inorganic pigments with excellent weather resistance and heat resistance, and are widely used, for example, as colorants for paints, synthetic resins, and ceramics.

The composite oxide green pigment is a spinel type compound made of oxides of cobalt, zinc, nickel, and titanium, and is mainly produced by a dry method. In addition, the wet method has already been developed for the production of green inorganic pigments (Japanese Unexamined Patent Publication No.
The present applicant has filed a patent application for this patent as (No. 74599).

In this method, titanium oxide or metatitanic acid is dispersed in an aqueous medium and the other three metal components are co-precipitated, but it is currently difficult to obtain transparent fine particle type particles using these conventional methods. It is.

[Problem to be solved by the invention] The dry method involves mixing cobalt, zinc, nickel, and titanium oxides, coexisting flux, and firing at high temperature.
Next, the sintered particles are pulverized using a powerful pulverizer to form pigments, but unless the constituent oxides are fine particles, the product after firing is unlikely to turn into transparent fine particles. Even so, it is sintered during firing and requires a large amount of energy for pulverization.

On the other hand, in the wet method, titanium oxide or metatitanic acid, which has a high proportion of constituent components, is used as a base and has a size that does not agglomerate during drying, and other constituent metal salts are precipitated with an alkaline precipitant such as caustic soda. Because of this, fine particle type products were not obtained. In addition, when titanium is co-precipitated as a metal salt such as titanium tetrachloride, sufficient color development cannot be obtained and it agglomerates during drying, making it difficult to calcinate and crush it to form a pigment. It is.

[Means for Solving the Problems 1] As a result of intensive research in order to meet the above-mentioned needs, the present invention has been developed to solve the above-mentioned needs by adding hydrogen peroxide or peroxo acid or peroxo acid salt when using an aqueous titanium solution in a wet precipitation method. It has been discovered that it is possible to satisfy the following characteristics.

That is, the present invention provides cobalt, zinc,
When adding an aqueous solution containing titanium to an aqueous solution in a nickel container, hydrogen peroxide or a peroxo acid or peroxo acid salt is also added at the same time to form a mixed solution, and an alkaline aqueous solution such as caustic soda is used as a precipitant. This is a method for producing a fine particle composite oxide green pigment, which is characterized by co-precipitating elements, filtering, washing with water, drying, and then firing. The microparticle transparent composite oxide green pigment thus obtained is expected to be applied to, for example, transparent paints, transparent thin films, printing inks, cosmetics, phosphors, abrasives, etc. by utilizing its properties.

[Action] Titanium peroxide is produced by adding hydrogen peroxide or peroxo acid or peroxo salt to an aqueous solution containing titanium, and when this product precipitates, it precipitates as fine particles and aggregates with a certain size. Therefore, even though it is a fine particle after drying, it rises softly as a pigment precursor, and since each component is precipitated uniformly, the color develops sufficiently even when fired at a relatively low temperature, resulting in a soft and transparent composite oxide. A green pigment is obtained.

[Example] Next, preferred embodiments of the present invention will be described in more detail.

The salts of each constituent element other than titanium used in the present invention include sulfates, nitrates, carbonates, chlorides, acetates, etc., all of which are used in the production of American composite oxide green pigments. be able to.

In the case of titanium, reagents or industrial raw materials such as titanium tetrachloride and titanyl sulfate can be used, and commonly used reagents and industrial raw materials can also be used for hydrogen peroxide or peroxoacids and peroxoacid salts. .

In the above, the composition ratio of each component is best when the metal molar ratio is cobalt:zinc dinickel:titanium=1:1:2:2, and in this case, the green coloring is good.

However, unless there is a significant deviation from this ratio, transparency will not deteriorate significantly. According to research results, when titanium is too high, it becomes slightly whitish and transparency deteriorates, while when it is low, it tends to become dull.

The metal salts of the constituent elements as described above are dissolved in water to form a mixed aqueous solution, and the concentration thereof is preferably about 5 to 50% by weight as a whole in the molar ratio as described above.

Further, hydrogen peroxide or an aqueous solution of peroxo acid or peroxo acid salt is added to the aqueous solution mixed in this manner to prepare a mixed aqueous solution containing the metal salts of the constituent components. According to detailed research by the present inventors, at this time, upon addition of hydrogen peroxide or peroxo acid or peroxo acid salt aqueous solution, the mixed aqueous solution changes from slightly greenish dark brown to dark red with slight heat generation. and titanium peroxide is produced.

The amount added at this time is O, OS, per mole of titanium in the case of hydrogen peroxide to return a transparent composite oxide green pigment.
A suitable range is from 1.3 moles to 1.3 moles; if the amount is less than this, clear transparency cannot be obtained. Moreover, if the amount exceeds this range, hydrogen peroxide is wasted, and working conditions become worse, such as excessive hydrogen peroxide being released out of the system as a mist or requiring a longer water washing time.

The mixed aqueous solution thus obtained is simultaneously dropped into precipitated water prepared in advance using an alkaline aqueous solution such as caustic soda as a precipitant. The reaction concentration at this time does not have a particularly bad effect on transparency, but considering working conditions etc., it is preferably 0.05 mol/l to 0.4 mol/l.
Mol/l (based on titanium metal) is suitable.

Further, the effect can be sufficiently exhibited if the synthesis temperature is in the usual range, that is, in the range of 0°C to 100°C. However, 80
When the temperature exceeds ℃, the transparency tends to be slightly impaired. In addition, it is fine if the pH during synthesis is on the alkaline side of 7 or more, but as the pH shifts to the alkaline side, it tends to become dull. If the pH is lower than 7, hydroxides of nickel, cobalt, and zinc will be difficult to precipitate, which will adversely affect color development.

In this way, after forming a precipitate while stirring for 30 minutes to 1 hour, about 1 hour was added to complete the reaction.
A period of ripening can be carried out to complete the precipitation reaction.

Next, by filtering the precipitated coprecipitate, the water content becomes approximately 40% to 80%, which is then
The fine particulate composite oxide green pigment of the present invention can be obtained by drying at a temperature of about ~120°C and firing it in an oxidizing atmosphere at a temperature of 600°C to 1000°C for 30 minutes to 1 hour to develop color. can.

The fine particle composite oxide green pigment of the present invention obtained in this way has a
It was transparent and had a deep color tone, and had good dispersibility in paints and the like.

Example 1 83.23 parts of nickel chloride hexahydrate, 50.93 parts of cobalt nitrate hexahydrate, 50.32 parts of zinc sulfate heptahydrate, and 100.45 parts of a titanium tetrachloride aqueous solution with a titanium content of 16.7% by weight. It is weighed out, dissolved in 830 parts of water, and then 70 parts of technical 35% by weight hydrogen peroxide are added thereto. The aqueous solution immediately changes color from dark greenish brown to dark red with slight exotherm.

Next, 87.5 parts of caustic soda as a precipitant was weighed out and water was added to make a total of about 1000 parts.

2400 parts of precipitated water prepared in advance is heated and maintained at about 45 DEG C. with a gas burner, electric heater, etc., and a mixed salt aqueous solution and a caustic soda aqueous solution are simultaneously added dropwise thereto to carry out a precipitation reaction over about 30 minutes to 1 hour.

At this time, care should be taken to keep the pH at 7 and the temperature of the aqueous solution to be maintained at 45°C. Once the dripping is finished,
In order to ensure complete precipitation, the pH is increased to about 8, and the aqueous solution is then aged for 1 hour while maintaining the temperature of the solution at 45°C.

Next, when the ripening is completed, the product is taken out, thoroughly washed with water by decantation to remove residual salt, and filtered. Then, it is dried at a temperature of 100 to 120°C for 12 hours or more.

The dried pigment precursor is fired at 800° C. for 1 hour in an oxidizing atmosphere. The fired product was then dispersed in melamine alkyd resin, PHR40, at Bainton Acres, and the color was spread on art paper with a black band using a 6 mil applicator to observe the color tone.

When compared with conventional products, the pigment thus obtained had a transparent and consistent color tone and had good dispersibility.

Example 2 Titanyl sulfate dihydrate with titanium content of 33.7% by weight 82.9%
Add 5 parts to 930 parts of water prepared in advance and leave to stand for about 1 hour while stirring to completely dissolve. Next, the same amounts of nickel chloride hexahydrate, cobalt nitrate hexahydrate, and zinc sulfate heptahydrate as in Example 1 were weighed out and dissolved in the titanium aqueous solution.

Hereinafter, the same method as in Example 1 will be used.

The pigment thus obtained was transparent and had a deep color tone, as in Example 1, and had good dispersibility.

Comparative Example 1 The same series of operations as in Example 1 are carried out, except that hydrogen peroxide is not added.

The pigment thus obtained did not have sufficient color development compared to Example 1, had a whitish appearance overall, and lacked transparency. Also, when compared with the conventional product, the same tendency was observed.I:.

Comparative Example 2 The same series of operations as in Example 2 are carried out, except that hydrogen peroxide is not added.

The product obtained in this way is the case of Comparative Example 1 * Hue /
Transparency: Showed the same tendency as melamine alkyd resin/PHR40.

The following results are summarized in Table 1.

(Blank below) [Advantageous Effects of the Invention 1 According to the present invention, when an aqueous solution of a titanium compound is added to an aqueous solution of cobalt, zinc and nickel in a container to form a mixed solution, and an aqueous alkali solution is added to the mixed solution for coprecipitation, Since at least one selected from peroxide, hydrogen oxide, peroxo acid, and peroxo acid salt is added to the mixed solution, co-precipitation of cobalt, zinc, nickel, and titanium hydroxides is uniformly performed. It is easy to dehydrate materials, and even when fired at a relatively low temperature, a transparent and deep green pigment can be obtained.

Since the composite oxide green pigment of the present invention is a soft particle, it is easily pulverized and has extremely excellent dispersibility.

Claims (1)

[Scope of Claims] 1. At least one selected from hydrogen peroxide, peroxo acids, and peroxo acid salts is added to a mixed aqueous solution of nickel salts, cobalt salts, zinc salts, and titanium compounds, and then an alkaline aqueous solution is added to the mixture. A method for producing a fine-particle composite oxide green pigment, which comprises generating a precipitate and firing the coprecipitate. 2 Peroxoacid is peroxosulfuric acid, peroxonitric acid,
The method for producing a particulate composite oxide green pigment according to claim 1, wherein the pigment is peroxocarbonic acid, peroxoboric acid, and peroxolinic acid. 3. The method for producing a particulate composite oxide green pigment according to claim 1, wherein the peroxoacid salt is an alkali metal salt, an alkaline earth metal salt, or an ammonium salt. 4. The method for producing a particulate composite oxide green pigment according to claim 1, wherein the firing temperature is 600°C or higher.