In situ preparation of bismuth vanadate composite pigments

Abstract

The present invention belongs to the technical field of inorganic pigment production, and particularly relates to a method for in-situ preparation of bismuth vanadate composite pigment. This preparation method involves first dissolving a bismuth compound in an acidic solution, adding a surfactant to dissolve the compound thoroughly, and then adding nickel titanium yellow particles to the mixture. A vanadium compound is then added to the mixture under strong shearing force, and the mixture is allowed to react at a predetermined temperature and pH. The precipitate separated from the mixture is washed, dried, and then heat-treated to obtain a bismuth vanadate composite pigment powder. Under strong shearing force, the synthesis reaction of bismuth vanadate can be carried out uniformly in-situ on the surface of nickel titanium yellow. This method allows for faster and more uniform in-situ synthesis and avoids the need for large amounts of basic solution in conventional methods. The resulting bismuth vanadate composite pigment has high chromaticity, superior hiding power, and tint color intensity. The method of the present invention is green and efficient, achieves uniform reaction, and produces excellent product performance, making it suitable for industrial continuous production.

Description

[Technical Field]

[0001] The present invention belongs to the technical field of inorganic pigment production, and in particular to a method for in situ production of bismuth vanadate composite pigments. [Background technology]

[0002] Bismuth vanadate is a green, environmentally friendly, high-performance, yellow inorganic pigment that is often used as a replacement for heavy metal yellow pigments such as chrome yellow and cadmium yellow. Bismuth vanadate pigments have many excellent properties, including easy dispersion, vivid color, excellent weather resistance, and high tinting strength. However, due to the high cost of raw materials, bismuth vanadate pigments are expensive, costing more than ten times that of lead chrome yellow and organic yellow pigments. This significantly hinders the widespread application of green, environmentally friendly bismuth vanadate pigments in the market. Currently, bismuth vanadate pigments are only used in high-end products such as high-end paints and food contact plastics, where pigment performance and environmental protection are highly demanding.

[0003] The production of bismuth vanadate composite pigments is one of the main ways to reduce costs. By compounding with lower-cost materials, the use of expensive raw materials such as vanadium and bismuth can be reduced, resulting in significant cost savings. Bismuth vanadate composite pigments can be produced primarily through solid-phase, liquid-phase, and twin-screw extrusion processes. Of these three methods, the liquid-phase process produces bismuth vanadate pigments with the smallest particle size, highest purity, and the most controllable adjustments and controllability. However, the reaction still suffers from the drawback of inhomogeneous reactions, which makes it difficult to effectively and uniformly compound the two materials, resulting in significantly lower pigment performance than bismuth vanadate pigments alone.

[0004] Nickel titanium yellow pigments have a wide color range, are easy to disperse, have good hiding power and long service life, and possess excellent gloss and color retention among pale yellow pigments. Nickel titanium yellow is inexpensive and is widely used in coatings for architecture, steel, and painting, as well as in general plastics, rubber, building materials, ceramics, and other applications. Nickel titanium yellow is a pale yellow pigment with a weaker yellow color than bismuth vanadate pigments. Strong shear forces are generated by the relative high-speed movement of the rotor / stator, effectively promoting uniformity of the reaction through rapid dispersion. The present invention utilizes the action of strong shear forces to simplify the synthesis reaction of bismuth vanadate and promote the in-situ uniform composite of bismuth vanadate and nickel titanium yellow. A low-cost, high-performance bismuth vanadate composite pigment can be obtained. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide an in-situ method for producing bismuth vanadate composite pigments, which overcomes the shortcomings of the prior art. It proposes to combine the advantages of the high color properties of bismuth vanadate pigments and the low cost of nickel titanium yellow, and to use nickel titanium yellow as the core to uniformly synthesize bismuth vanadate in-situ on the surface of nickel titanium yellow under the action of strong shear force, thereby finally forming a bismuth vanadate composite pigment with excellent performance. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention employs the following technical means. The in-situ production method for bismuth vanadate composite pigment is as follows: first, a bismuth compound is dissolved in an acidic solution, and then an appropriate amount of surfactant is added to dissolve the bismuth compound sufficiently. Then, nickel titanium yellow pigment particles are added thereto; a vanadium compound is added to the mixed solution under the action of strong shearing force, and the mixture is reacted at a predetermined temperature and pH value. The precipitate separated from the mixed solution is washed, dried, and then heat-treated to obtain the bismuth vanadate composite pigment powder.

[0007] The bismuth compound is at least one of bismuth nitrate, bismuth sulfate, and bismuth oxide, and the concentration of elemental bismuth in the acidic solution is 0.01 to 0.4 mol / L. The acid solution is a nitric acid solution or a hydrochloric acid solution, and the concentration of the acid solution is 1 to 3 mol / L.

[0008] The surfactant is any one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and polyvinylpyrrolidone, and the concentration of the surfactant added is 0.001 mol / L to 0.2 mol / L. The nickel titanium yellow particles have a particle diameter of less than 2 μm, and the amount of the nickel titanium yellow particles added is 15% to 200% of the mass of the vanadium compound.

[0009] The vanadium compound is at least one of ammonium metavanadate, sodium metavanadate, potassium metavanadate, and vanadium oxide.

[0010] The basic solution is one of sodium hydroxide, potassium hydroxide, and aqueous ammonia, and the concentration of the basic solution is 1 to 3 mol / L. The strong shearing force is achieved by a high-speed shearing machine, and the rotation speed of the high-speed shearing machine is 500 rpm to 8000 rpm.

[0011] The reaction temperature is 40° C. to 90° C., the pH value is 3.5 to 7, and the reaction time is 0.5 to 3 hours. The temperature of the heat treatment is 350° C. to 500° C., and the treatment time is 1 hour to 2 hours. [Effects of the Invention]

[0012] The present invention has the following advantageous effects compared to the prior art. 1) Combining the advantages of the high color properties of bismuth vanadate pigment and the low cost of nickel titanium yellow, we propose to synthesize a yellow bismuth vanadate-nickel titanium yellow composite inorganic pigment in situ using nickel titanium yellow as the core. The pigment's main properties, Lab value, hiding power, and tint color intensity, are all significantly improved.

[0013] 2) Under the action of strong shear force, the synthesis reaction of bismuth vanadate is ensured to be carried out uniformly on the surface of nickel titanium yellow, and the use of a large amount of basic solution as the base liquid in the conventional method is avoided. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an XRD graph of the bismuth vanadate composite pigments produced in Examples 1 to 6 of the present invention and the bismuth vanadate alone produced in the comparative example. [Figure 2] 1 shows ultraviolet absorption spectra of the bismuth vanadate composite pigments produced in Examples 1 to 6 of the present invention and bismuth vanadate alone produced in a comparative example. [Figure 3] 1 shows the results of measuring the hiding power and coloring intensity of Example 1 of the present invention and a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0015] The technical solutions of the present invention will be described below clearly and completely based on specific embodiments, but it is obvious that the described embodiments are only some of the embodiments of the present invention and not all of the embodiments.

[0016] In order to more clearly describe the specific embodiments of the present invention or the technical means in the prior art, the following specific examples are briefly introduced to explain the specific embodiments or the prior art. It is clear that the specific examples described below are part of the embodiments of the present invention, and those skilled in the art can obtain other specific examples based on these specific examples without creative work. Generally, the elements of the embodiments of the present invention described or suggested in the specific embodiments herein can be arranged or designed in a myriad of different combinations. Therefore, the detailed description of the embodiments of the present invention provided in the specific embodiments below is not intended to limit the scope of protection of the present invention, but is merely intended to illustrate particular embodiments of the present invention.

[0017] Example 1 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). The mixture was stirred with a magnetic stirrer until completely dissolved. 0.7 g of sodium dodecylbenzenesulfonate was then added and stirred until completely dissolved. 0.4 g of nickel titanium yellow particles were then added and stirred until uniformly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 2000 rpm in a high-speed shearing machine. The mixture was heated to 70°C, the pH was adjusted to 5, and the mixture was reacted under continuous shearing conditions in a high-speed shearing machine for 1.5 hours. The precursor precipitate was separated from the mixture, washed three times with deionized water and absolute ethanol, and then dried in a vacuum drying oven for 12 hours. It was then heat-treated at 350°C for 1.5 hours to obtain a yellow bismuth vanadate-nickel titanium yellow composite inorganic pigment. Its oil absorption was 20 g / 100 g. Its L * a * b * The chromaticity values ​​are shown in Table 1.

[0018] Example 2 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). The mixture was stirred with a magnetic stirrer until completely dissolved. 0.9 g of sodium dodecyl sulfate was then added and stirred until completely dissolved. 0.6 g of nickel titanium yellow particles were added and stirred until uniformly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 3000 rpm in a high-speed shearing machine. The mixture was heated to 70 °C, the pH was adjusted to 5.5, and the mixture was reacted under continuous shearing conditions in a high-speed shearing machine for 1.5 h. The precursor precipitate was separated from the mixture, washed three times with deionized water and absolute ethanol, and then dried in a vacuum drying oven for 12 h. It was then heat-treated at 400 °C for 1.5 h to obtain a yellow bismuth vanadate-nickel titanium yellow composite inorganic pigment. Its oil absorption was 23 g / 100 g. Its L * a * b * The chromaticity values ​​are shown in Table 1.

[0019] Example 3 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). The mixture was stirred with a magnetic stirrer until completely dissolved. 1.6 g of polyvinylpyrrolidone was then added and stirred until completely dissolved. 0.8 g of nickel titanium yellow particles were then added and stirred until uniformly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 4000 rpm in a high-speed shearing machine. The mixture was heated to 70°C, the pH was adjusted to 6, and the mixture was reacted under continuous shearing conditions in a high-speed shearing machine for 1.5 hours. The precursor precipitate was separated from the mixture, washed three times with deionized water and absolute ethanol, and then dried in a vacuum drying oven for 12 hours. It was then heat-treated at 380°C for 1.5 hours to obtain a yellow bismuth vanadate-nickel titanium yellow composite inorganic pigment. Its oil absorption was 22 g / 100 g. Its L * a * b * The chromaticity values ​​are shown in Table 1.

[0020] Example 4 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). The mixture was stirred with a magnetic stirrer until completely dissolved. 3.10 g of sodium dodecyl sulfate was then added and stirred until completely dissolved. 1.00 g of nickel titanium yellow particles was then added and stirred until uniformly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 4000 rpm in a high-speed shearing machine. The mixture was heated to 70 °C, the pH was adjusted to 6, and the mixture was reacted under continuous shearing conditions in a high-speed shearing machine for 1.5 h. The precursor precipitate was separated from the mixture, washed three times with deionized water and absolute ethanol, and then dried in a vacuum drying oven for 12 h. It was then heat-treated at 400 °C for 1.0 h to obtain a yellow bismuth vanadate-nickel titanium yellow composite inorganic pigment. Its oil absorption was 23 g / 100 g. Its L * a * b * The chromaticity values ​​are shown in Table 1.

[0021] Example 5 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). Stirring was continued with a magnetic stirrer until completely dissolved. 1.5 g of sodium dodecyl sulfate was then added and stirred until completely dissolved. 1.22 g of nickel titanium yellow particles were added and stirred until uniformly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 4000 rpm in a high-speed shearing machine. The mixture was heated to 70 °C, the pH was adjusted to 6, and the mixture was reacted under continuous shearing conditions in a high-speed shearing machine for 1.5 h. The precursor precipitate was separated from the mixture, washed three times with deionized water and absolute ethanol, and then dried in a vacuum drying oven for 12 h. It was then heat-treated at 400 °C for 1.0 h to obtain a yellow bismuth vanadate-nickel titanium yellow composite inorganic pigment. Its oil absorption was 24 g / 100 g. Its L * a * b * The chromaticity values ​​are shown in Table 1.

[0022] Example 6 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). Stirring was continued with a magnetic stirrer until completely dissolved. 2.0 g of sodium dodecyl sulfate was then added and stirred until completely dissolved. 2.44 g of nickel titanium yellow particles were added and stirred until uniformly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 4000 rpm in a high-speed shearing machine. The mixture was heated to 70 °C, the pH was adjusted to 6, and the mixture was reacted under continuous shearing conditions in a high-speed shearing machine for 1.5 h. The precursor precipitate was separated from the mixture, washed three times with deionized water and absolute ethanol, and then dried in a vacuum drying oven for 12 h. It was then heat-treated at 400 °C for 1.0 h to obtain a yellow bismuth vanadate-nickel titanium yellow composite inorganic pigment. Its oil absorption was 23 g / 100 g. Its L * a * b * The chromaticity values ​​are shown in Table 1.

[0023] Comparative Example 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). Stirring was continued with a magnetic stirrer until completely dissolved. 1.44 g of sodium dodecyl sulfate was added and stirring was continued until completely dissolved. 2.44 g of sodium metavanadate was added to the mixture at 4000 rpm in a high-speed shearing machine. The temperature of the mixture was raised to 70°C, the pH was adjusted to 6, and the mixture was reacted under continuous shearing conditions with the high-speed shearing machine for 1.5 hours. The precursor precipitate was separated from the mixture, washed three times with deionized water and absolute ethanol, and then dried in a vacuum drying oven for 12 hours. Subsequently, the mixture was heat-treated at 400°C for 1 hour to obtain a yellow bismuth vanadate inorganic pigment. The oil absorption was 22 g / 100 g. The L * a * b * The chromaticity values ​​are shown in Table 1.

[0024] Table 1 shows the comparison of Lab chromaticity values, band gaps, and weather resistance levels between the bismuth vanadate composite pigments produced in Examples 1 to 6 of the present invention and the comparative examples.

[0025] [Table 1]

[0026] While the present invention has been shown and described with reference to exemplary embodiments, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and variations can be made to these exemplary embodiments without departing from the spirit and scope of the present invention. The scope of the present invention is limited by the appended claims and their equivalents.

Claims

1. The in-situ preparation method for the bismuth vanadate composite pigment is as follows: first, a bismuth compound is dissolved in an acidic solution, and then an appropriate amount of surfactant is added to dissolve the bismuth compound sufficiently. Then, nickel titanium yellow pigment particles are added thereto; a vanadium compound is added to the mixed solution under the action of strong shearing force, and the mixture is reacted at a predetermined temperature and pH value. The precipitate separated from the mixed solution is washed, dried, and then heat-treated to obtain the bismuth vanadate composite pigment powder.

2. 2. The method for in-situ preparation of bismuth vanadate composite pigment according to claim 1, wherein the bismuth compound is at least one of bismuth nitrate, bismuth sulfate, and bismuth oxide, the concentration of bismuth element in the acidic solution is 0.01-0.4 mol / L, and the molar ratio of vanadium element to bismuth element is 1:0.8-1:1.

5.

3. 2. The method for producing bismuth vanadate composite pigment in situ according to claim 1, wherein the acid solution is a nitric acid solution or a hydrochloric acid solution, and the concentration of the acid solution is 1-3 mol / L.

4. 2. The method for producing bismuth vanadate composite pigment in situ according to claim 1, wherein the surfactant is any one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and polyvinylpyrrolidone, and the concentration of the surfactant added is 0.001 mol / L to 0.2 mol / L.

5. The method for preparing the bismuth vanadate composite pigment in situ according to claim 1, characterized in that the particle size of the nickel titanium yellow particles is less than 2 μm, and the amount of the nickel titanium yellow particles added is 15% to 200% based on the mass of the vanadium compound.

6. 2. The method for producing a bismuth vanadate composite pigment in situ according to claim 1, wherein the vanadium compound is at least one of ammonium metavanadate, sodium metavanadate, potassium metavanadate, and vanadium oxide.

7. The in-situ method for producing bismuth vanadate composite pigment according to claim 1, characterized in that the strong shearing force is achieved by a high-speed shearing machine, and the rotation speed of the high-speed shearing machine is 500 rpm to 8000 rpm.

8. 2. The in-situ method for preparing bismuth vanadate composite pigment according to claim 1, wherein the reaction temperature is 40°C to 90°C, the pH value is 3.5 to 7, and the reaction time is 0.5h to 3h.

9. 2. The in-situ method for preparing bismuth vanadate composite pigment according to claim 1, wherein the temperature of the heat treatment is 350°C to 500°C, and the treatment time is 1h to 2h.

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