JP4680646B2 - Method for producing yellow pigment and yellow pigment - Google Patents

Description

  The present invention relates to a method for producing a yellow pigment and a yellow pigment, and more particularly to an inorganic yellow pigment exhibiting a bright yellow color and a method for producing the same.

  Conventional yellow pigments include, for example, inorganic pigments such as cadmium yellow having a cadmium sulfide composition, aureolin (also known as cobalt yellow) having a cobalt nitrite / potassium composition, and organic azo yellows such as lemon yellow and permanent yellow. Pigments are used.

  However, the inorganic pigments are slightly inferior in colorability as compared to the azo yellow, and have a problem that both are slightly toxic and use applications are limited.

  Therefore, in recent years, organic pigments such as azo yellow, which have good color developability and are easy to change color because they are artificial pigments, are mainly used as yellow pigments.

  However, since the organic pigment is slightly inferior in weather resistance, a yellow pigment having more excellent weather resistance has been desired.

In Patent Document 1, 35% hydrogen peroxide water is added to gelled titanium hydroxide (Ti (OH) ₄ ) to obtain a yellow transparent amorphous titanium oxide sol. This amorphous titanium oxide sol and an alkali metal A coating agent obtained by mixing a compound has been proposed. This coating agent is coated on a substrate such as a tile.

  In Patent Document 2, an aqueous solution such as titanium chloride and titanium sulfate is reacted with an alkaline aqueous solution such as ammonia and caustic soda to precipitate a titanium hydroxide gel called orthotitanic acid, and the titanium hydroxide gel is separated by decantation. Washing with water, adding hydrogen peroxide water to this titanium hydroxide gel to obtain a yellow transparent viscous liquid, and obtaining a coating agent for forming a titanium oxide film containing this yellow transparent viscous liquid and a phosphoric acid compound. Proposed

JP-A-11-92689 Republished WO2002 / 061005

  However, any of the above yellow transparent viscous liquids is in the form of a sol or gel, and these yellow transparent viscous liquids can only be used as a coating agent, and cannot themselves be used as pigments.

  On the other hand, organic pigments such as azo yellow that can change color developability and color are slightly inferior in weather resistance as described above.

  This invention is made | formed in view of the said subject, and provides the inorganic pigment which colors bright yellow, and its manufacturing method.

  The method for producing a yellow pigment of the present invention has the following characteristics.

( 1 ) A drying step in which a sol-like titanate pigment is dried to produce a scaly titanate pigment powder, and a yellow pigment is obtained by allowing hydrogen peroxide to act on the scaly titanate pigment powder. It is a manufacturing method.

  As will be described later, the sol-like titanic acid pigment is an extremely thin scaly pigment, and by drying in the state of this ultrathin scaly pigment, the ultrathin scaly titanic acid having a high aspect ratio is obtained. A pigment powder is obtained. By reacting hydrogen peroxide with the oxygen atom-rich titanate pigment powder having a high aspect ratio, a more vivid ultrathin scale powder yellow pigment having a high aspect ratio can be obtained. In addition, since the powder ultrathin flaky yellow pigment has a high aspect ratio as described above, the amount of the pigment powder existing in the same volume is relatively larger than other pigments having a low aspect ratio. As a result, since the surface area of the yellow pigment in the same volume is increased, the yellow pigment appears to be clearer to the naked eye.

( 2 ) In the method for producing a yellow pigment as described in ( 1 ) above, the drying step is a freeze-drying step in which a sol-like titanate pigment is freeze-dried.

  As will be described later, the titanate is usually formed by alternately laminating titanate layers and interlayer ions. Further, the layered titanate is subjected to an acid treatment to exchange a replaceable metal cation with hydrogen. Layered titanic acid is obtained by substitution with ions or hydronium ions. An organic basic compound is allowed to act on the layered titanic acid and the layers are peeled to obtain an aqueous medium dispersion (peeled sol) of flaky titanic acid. As the organic basic compound, dimethylethanolamine (DMEA) is desirable. By lyophilizing the flaky titanic acid aqueous medium dispersion (release sol), the organic basic compound (for example, DMEA) in the dispersion in the release sol can be removed while substantially maintaining the release dispersion state. it can. As a result, it is possible to obtain a flaky titanate pigment powder that is extremely thin and has a higher aspect ratio. By reacting this with hydrogen peroxide, a yellow pigment that produces a brighter yellow color can be obtained.

( 3 ) In the method for producing a yellow pigment according to any one of (1) and (2) , the yellow pigment obtained has a Munsell color system and a Munsell value in the range of 5Y8 / 2 to 5Y10 / 14. is there.

  A yellow pigment having a Munsell value in the above range develops a bright yellow color with high brightness and saturation.

  The yellow pigment of the present invention has the following characteristics.

A yellow pigment produced by the method for producing a yellow pigment according to any one of (1) to ( 3 ) above.

  These yellow pigments are clearer yellow pigments.

  According to the present invention, by reacting a titanium oxide compound with hydrogen peroxide, the titanium oxide compound is yellowed, thereby obtaining a yellow pigment that develops an inorganic bright yellow color.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Production method of yellow pigment]
The method for producing a yellow pigment according to a preferred embodiment of the present invention is such that a yellow pigment is obtained by allowing hydrogen peroxide water to act on a titanium oxide compound pigment powder or a coated pigment powder whose substrate surface is coated with a titanium oxide compound. It is a manufacturing method of a pigment.

Here, as the titanium oxide compound, for example, titanium oxide containing Ti ₂ O ₃ and TiO ₂ , layered titanate is treated with an acid to form layered titanic acid, and then an organic basic compound is allowed to act between the layers. It is a compound selected from the group consisting of exfoliated flaky titanic acid.

The titanium oxide compound pigment powder is obtained by treating a titanium oxide pigment containing Ti ₂ O ₃ or TiO ₂ or a layered titanate with an acid to form a layered titanic acid, and then allowing an organic basic compound to act. It is a pigment powder selected from titanic acid pigments made of flaky titanic acid from which the pigment is peeled, and the shape of these pigment powders is preferably scaly.

  In addition, as the coated pigment powder (hereinafter referred to as “coated pigment powder”) whose base material surface is coated with the titanium oxide compound, for example, the base material may be selected from scaly alumina, mica, silica, or the like. desirable.

In addition, as shown in FIG. 1, the titanate pigment used in the present embodiment has a thickness T ₁ of the titanate pigment 10 of 10 to 200 nm and a longitudinal length (particle diameter) D ₁ of 10 to 10. The aspect ratio (ratio of thickness to length in the longitudinal direction) is 250 to 3000. The titanate pigment is preferably a titanate pigment composed of flaky titanic acid obtained by treating a layered titanate with an acid to form layered titanic acid, and then separating the layers by the action of an organic basic compound. Ultrathin scaly titanic acid pigments that are rich in atoms and have a high valence and a D1 of ₁₀ to 50 nm are preferred. Here, the higher the valence, the more vivid yellow color develops due to the reaction with hydrogen peroxide described later.

  The titanium oxide pigment is spherical and has a diameter of 10 to 200 nm. Moreover, as a titanium oxide pigment, a rutile type titanium dioxide pigment is preferable, for example.

  The coated pigment powder is a powder of titanium oxide-coated pigment 20 in which the surface of a flaky substrate 24 made of flaky alumina, mica, silica or the like is coated with a titanium oxide film 22 as shown in FIG. 2 is a titanic acid-coated pigment in which the titanium oxide film 22 in 2 is replaced with a titanic acid film, and the surface of the scaly substrate 24 is coated with the titanic acid film.

This coated pigment powder has a thickness T ₂ of 400 to 500 nm, a length (particle size) D ₂ in the longitudinal direction of about 15 to 20 μm, and an aspect ratio of 30 to 50.

Below, an example of a method for producing a yellow titanate pigment powder is obtained by treating layered titanate with an acid to form layered titanic acid, and then reacting an organic basic compound to separate the layers to form titanium. An acid pigment will be described as an example with reference to FIGS. For the TiO ₄ pigment, a yellow pigment powder can be obtained by the same production method.

As shown in FIG. 3, layered titanate K _0.8 Li _0.27 Ti _1.73 O ₄ is treated with acid and the exchangeable metal cation is replaced with hydrogen ion or hydronium ion to form layered titanate (eg, H _1.07 Ti _1.73 O ₄ .nH ₂ O) is obtained. An organic basic compound is allowed to act on the layered titanic acid and the layers are peeled to obtain an aqueous medium dispersion (peeled sol) of flaky titanic acid. As the organic basic compound, dimethylethanolamine (DMEA) is desirable.

<Synthesis of flaky titanic acid dispersion>
(Synthesis Example 1)
A raw material in which 67.01 g of titanium oxide, 26.78 g of potassium carbonate, 12.04 g of potassium chloride and 5.08 g of lithium hydroxide were pulverized and mixed in a dry process was calcined at 1020 ° C. for 4 hours. 7.9 kg of 10.9% aqueous slurry of the obtained powder was prepared, 470 g of 10% aqueous sulfuric acid solution was added and stirred for 2 hours, and the pH of the slurry was adjusted to 7.0. What was separated and washed with water was dried at 110 ° C. and then calcined at 600 ° C. for 12 hours. The obtained white powder was layered titanate K _0.6 Li _0.27 Ti _1.73 O _3.9 and had an average major axis of 15 μm.

65 g of this layered titanate was dispersed and stirred in 5 kg of 3.5% hydrochloric acid, reacted at 40 ° C. for 2 hours, separated by suction filtration, and washed with water. The obtained layered titanic acid had a K ₂ O remaining amount of 2.0% and a metal ion exchange rate of 94%.

  While dispersing and stirring the total amount of layered titanic acid obtained in 1.6 kg of deionized water, a solution prepared by dissolving 34.5 g of dimethylethanolamine in 0.4 kg of deionized water was added and stirred at 40 ° C. for 12 hours. Thus, a flaky titanic acid dispersion having a pH of 9.9 was obtained. The concentration was adjusted to 5.0% by weight by centrifugation at 10,000 rpm for 10 minutes. The obtained flaky titanic acid dispersion did not show solid sedimentation even after standing for a long time, and the solid content obtained by drying it at 110 ° C. for 12 hours showed a weight loss of 200 ° C. or more by TG / DTA analysis. Was 14.7% by weight, and the interlayer distance was 10.3 mm by XRD analysis.

Next, as shown in FIG. 4, the peeled sol-like titanate pigment is dried (S100). Here, lyophilization is desirable as the drying. In lyophilization, the solvent (mainly water) contained in the substance is changed to a “liquid” state by reducing the pressure while the substance containing the solvent is frozen. It is a method that removes the solvent from the frozen state under reduced pressure by using the phenomenon of “sublimation” that changes from “solid” to “gas” at once without passing, and the dispersion state of the substance in the solvent is almost maintained. Only the solvent can be removed. Moreover, since it is performed under reduced pressure, it is also called vacuum lyophilization. The conditions for the vacuum freeze-drying used in the present embodiment are appropriately selected according to the concentration of the peeling sol and the solvent, for example, -70 ° C to 0 ° C, preferably -60 ° C to -5 ° C, More preferably, the temperature is −10 ° C. to −5 ° C. (ice temperature) and the degree of vacuum is ² to 5 mmHg (2.7 to 6.7 hPa (N / m ² )). As the vacuum freeze dryer, for example, “TFD-550-8SP” (manufactured by Takara Manufacturing Co., Ltd.) can be used.

  By the delamination and freeze-drying, the solvent in the release sol is removed, and a scaly titanate pigment powder in which 10 to 100 layers of about 1 nm of titanic acid are laminated is obtained. The degree of delamination can be adjusted by appropriately selecting the amount of amines for generating a release sol, and a scaly titanate pigment in which 10 to 100 layers of titanic acid are laminated can also be obtained. .

  The scaly titanate pigment powder obtained by the above-described production method is allowed to act with a high concentration of 30 to 35% by weight of hydrogen peroxide to yellow the titanate pigment powder to obtain a yellow pigment powder (S110). . Here, by using a high-concentration hydrogen peroxide solution, the total amount of the hydrogen peroxide solution for yellowing the titanate pigment can be reduced, and the subsequent drying step can be shortened. In the subsequent drying step, any of normal normal temperature normal pressure drying (natural drying), heat drying, and freeze drying may be used.

  As a method of allowing the hydrogen peroxide solution to act on the titanate pigment powder, a method of spraying the hydrogen peroxide solution onto the titanate pigment powder by, for example, airless spray or air spray is desirable. The treatment amount of hydrogen peroxide is preferably selected as appropriate according to the desired color of the titanate pigment powder and the pigment surface area based on the aspect ratio of the titanate pigment powder. Based on the amount of the acid pigment powder and the aspect ratio of the titanate pigment powder, the addition amount of 30 wt% hydrogen peroxide water may be calculated and sprayed.

  The Munsell value in the Munsell color system of the yellow titanate pigment powder in the present embodiment is 5Y8 / 8 to 5Y10 / 14. It is desirable to appropriately calculate the addition amount of 30% by weight of hydrogen peroxide so as to fall within the Munsell value range and spray the titanate pigment powder.

  Here, the Munsell color system is a kind of numerical expression of colors based on three attributes representing color and a color cube. Color charts are arranged using cylindrical coordinates, lightness V is a vertical axis, and hue H is a color expression. Saturation C is arranged in the radial direction in the circumferential direction, and this color chart spatially arranged is called a color cube. Hue H (Hue) is indicated by the first two digits, the first digit is 0-10, and the second digit is the distance from the hue such as Y (yellow), YR (yellow red), R (red). To express. Next, the lightness V (Blue) is represented by a number ranging from 0 (complete darkness) to 10 (completely pure white). Finally, the saturation C (Chroma) starts from 0 (achromatic color) and becomes a vivid color. Is expressed as increasing. A “/” (slash) is inserted between the lightness and saturation numbers for discrimination.

  The Munsell color system is measured based on JIS Z 8721 (1944).

  Moreover, an example of the manufacturing method of yellow titanium oxide coating pigment powder is demonstrated below using FIG.

  For the coated pigment powder surface-coated with titanium oxide, a hydrogen peroxide solution having a high concentration of 30% to 35% by weight is sprayed onto the coated pigment powder by, for example, airless spraying or air spraying as described above. Yellowing is performed (S120). The treatment amount of hydrogen peroxide is preferably selected according to the desired color of the coated pigment powder and the pigment surface area based on the aspect ratio of the coated pigment powder. For example, the coated pigment powder per fixed volume Based on the amount and the aspect ratio of the coated pigment powder, it is preferable to calculate the amount of addition of 30% by weight hydrogen peroxide and spray it. In addition, when performing heat drying etc. later, you may immerse a coating pigment powder in hydrogen peroxide water.

  The Munsell value in the Munsell color system of the yellow titanium oxide pigment powder in the present embodiment is 5Y8 / 2 to 5Y9 / 5. It is desirable to appropriately calculate the addition amount of 30% by weight of hydrogen peroxide so as to fall within the Munsell value range and spray the titanate pigment powder.

[Black pearl coating]
The yellow pigment of the present embodiment is a powdered inorganic pigment, and is a pigment produced by the above-described method for producing a yellow pigment. The Munsell color system has a Munsell value of 5Y8 / 2 to 5Y10 / 14. In addition, a titanium oxide compound pigment is an inorganic yellow pigment obtained by treating hydrogen peroxide with a titanium oxide compound pigment powder or a coated pigment powder having a substrate surface coated with a titanium oxide compound. Here, the titanium oxide compound is selected from the compounds as described above. The yellow pigment is a yellow pigment powder that develops a brighter yellow color.

  Below, the manufacturing method of the yellow pigment of this invention and the yellow pigment obtained by the manufacturing method are demonstrated using an Example.

[Example 1]
The flaky titanic acid dispersion obtained in Synthesis Example 1 was vacuumed at −10 ° C. to −5 ° C. (ice temperature) using a vacuum freeze dryer “TFD-550-8SP” (manufactured by Takara Seisakusho). Freeze-drying was performed at a degree of 2 to 5 mmHg (2.7 to 6.7 hPa (N / m ² )). The flaky titanate pigment powder pulverized by freeze-drying had a thickness T ₁ of 50 nm and an aspect ratio of 400. 0.2 g of this flaky titanate pigment powder was weighed, and 1 mL of an excessive amount of 30% by weight of hydrogen peroxide was added dropwise thereto to yellow the pigment powder. The Munsell value of the obtained yellow pigment powder is shown in Table 1.

[Example 2]
0.2 g of rutile-type titanium dioxide-coated mica pigment powder having a thickness T ₂ of 400 nm and an aspect ratio of 50 was weighed, and 1 mL of an excess amount of 30% by weight of hydrogen peroxide was dropped into the pigment powder. Yellowed. The Munsell value of the obtained yellow pigment powder is shown in Table 1.

[Reference example]
In this reference example, instead of the vacuum freeze-drying in Example 1, the hydrochloric acid agglomeration method was used, and hydrochloric acid was added to the flaky titanic acid dispersion obtained in Synthesis Example 1 to agglomerate the pigment to agglomerate with the solvent. The pigment was separated, washed and dried to obtain agglomerated titanate pigment powder. This aggregate titanate pigment powder had a thickness T ₁ of 15 μm and an aspect ratio of 1. 0.2 g of this aggregated titanate pigment powder was weighed, and 1 mL of an excessive amount of 30% by weight of hydrogen peroxide solution was added dropwise thereto to yellow the pigment powder. The Munsell value of the obtained yellow pigment powder is shown in Table 1.

  From Table 1, it can be seen that the yellow pigment powder obtained by the method for producing a yellow pigment of the present invention develops a clear yellow color equivalent to or better than the permanent yellow, which is a conventional azo yellow, while being an inorganic pigment. . In addition, for example, the mycel value of “danpyroxide yellow”, which is a general inorganic yellow pigment, is 8.52Y8.9 / 9.0. From this, the yellow pigment of the present invention is compared with a general inorganic pigment. It can be seen that the yellow pigment powder obtained by this production method expresses a very clear yellow color. Table 2 shows that the titanic acid pigment powder is preferably obtained by freeze-drying rather than hydrochloric acid aggregation.

  The method for producing a yellow pigment and the yellow pigment of the present invention are effective for any use as long as the powdery yellow pigment is used. It can be used for film formation.

It is a figure explaining an example of the titanate pigment which makes hydrogen peroxide act in the manufacturing method of the yellow pigment of this invention. It is a figure explaining an example of the titanium oxide coating pigment which makes hydrogen peroxide act in the manufacturing method of the yellow pigment of this invention. It is a figure explaining an example of the manufacturing method of the titanate pigment used for the manufacturing method of the yellow pigment of this invention. It is a flowchart explaining the manufacturing process of the yellow titanate pigment powder of this Embodiment. It is a flowchart explaining the manufacturing process of the yellow titanium oxide coating pigment powder of this Embodiment.

Explanation of symbols

  10 Titanate pigment, 20 Titanium oxide-coated pigment, 22 Titanium oxide film, 24 Scale-like substrate.

Claims (4)

A drying step of drying the sol-like titanate pigment to produce scaly titanate pigment powder;
A method for producing a yellow pigment, wherein a hydrogen peroxide solution is allowed to act on the scaly titanate pigment powder to obtain a yellow pigment. In the manufacturing method of the yellow pigment of Claim 1 ,
The method for producing a yellow pigment, wherein the drying step is a freeze-drying step of freeze-drying a sol-like titanate pigment. In the manufacturing method of the yellow pigment of Claim 1 or Claim 2 ,
The yellow pigment obtained is a Munsell color system and has a Munsell value ranging from 5Y8 / 2 to 5Y10 / 14. The yellow pigment manufactured by the manufacturing method of the yellow pigment of any one of Claims 1-3 .

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