A water-based colored aluminum pigment, a preparation method thereof, and application thereof in coatings or inks

Abstract

The invention discloses a water-based colored aluminum pigment, a preparation method thereof, and application thereof in coatings or inks. The water-based colored aluminum pigment comprises flaky aluminum particles, porous silica coated on the surface of the flaky aluminum particles, and an organic dye adsorbed in the pores of the porous silica. The invention provides a water-based colored aluminum pigment, a preparation method thereof, and application thereof in coatings or inks, belonging to the technical field of aluminum pigments. The water-based colored aluminum pigment not only maintains the metallic luster of the original aluminum pigment, but also obtains bright colors by attaching an organic dye to the surface of the aluminum pigment after surface modification, and has the advantages of bright colors, high gloss, strong corrosion resistance, not easy to fade, and low raw material cost.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum pigments, and in particular relates to a water-based colored aluminum pigment and a preparation method thereof and application of the pigment in coatings or inks. Background Art

[0002] Aluminum pigment is aluminum particles with a smooth and extremely thin flaky structure. Because it can reflect visible light, it has a silvery-white metallic effect. It is commonly known as aluminum silver powder or aluminum silver paste. It is one of the most widely used metallic effect pigments and is widely used in many fields such as car paint, motorcycle paint, bicycle paint, plastic paint, architectural coatings, inks, mobile phone housings and buttons, electromechanical housings, electrical housings, metallic paints, etc., and the demand for aluminum pigments in industry is also increasing.

[0003] With the development of science and technology and modern industry, there are more and more varieties of aluminum pigments, the scope of application is also expanding, and the requirements for the quality of aluminum pigments are getting higher and higher. The quality of aluminum pigments is mainly reflected in the glossiness, hue and compatibility with the coating matrix. With people's pursuit of multi-colorization and increasing attention to environmental protection, the development of aluminum pigments with special properties is becoming more and more urgent. Water-based colored aluminum pigments can not only meet the requirements of multi-colorization but also solve the problem of hydrophilicity, and have broad application prospects. Self-study of the preparation technology of water-based colored aluminum pigments is of great significance to the development of my country's coatings industry and the improvement of product market competitiveness.

[0004] At present, there are three main methods for coloring aluminum pigments: one is to deposit inorganic pigments (such as iron oxide and cobalt oxide) by liquid phase deposition. The colored aluminum pigments prepared by this method need to deposit a layer of metal oxide on the surface, and need to be calcined in the later stage, which will make the dispersibility of the aluminum pigment in the resin and water medium worse. Although it is simple to operate and low in cost, it is not conducive to the preparation of coatings; the other is to first coat a layer of silica on the surface of aluminum particles or to co-coat silica with a silane coupling agent, and then deposit colored pigments to color the aluminum particles. Although this method has a simple process, the aluminum pigments prepared by this method have poor stability in solvents; another method is to introduce colored groups in the process of coating the aluminum pigment to color the aluminum pigment. This method has high color fastness but is more complicated to operate and not easy to mass produce.

[0005] For example, patent publication CN105153762A discloses a method for preparing a colorful aluminum composite pigment, which comprises first coating the surface of aluminum particles with a layer of silica and a silane coupling agent, and then depositing active dyes to color the aluminum particles. Since the coated silica layer is densely distributed, it usually has a small pore structure and a low specific surface area, making it impossible to adsorb colored pigments. Appropriate silane coupling agents must be added for modification before the active dyes can be chemically bonded to the surface of the aluminum pigment. Summary of the invention

[0006] Based on the above technical problems, the present invention provides a water-based colored aluminum pigment, a preparation method thereof and an application in coatings or inks. The water-based colored aluminum pigment attaches an organic dye to the surface of the surface-modified aluminum pigment, thereby maintaining the metallic luster of the original aluminum pigment and obtaining a bright color. The water-based colored aluminum pigment has the advantages of bright color, high gloss, strong corrosion resistance, not easy to fade, and low raw material cost.

[0007] The invention provides a water-based colored aluminum pigment, which comprises flaky aluminum particles, porous silicon dioxide coated on the surface of the flaky aluminum particles, and an organic dye adsorbed in the pores of the porous silicon dioxide.

[0008] In the present invention, the surface of the aluminum particles is coated with a layer of porous silica. Porous silica is a material with a highly porous structure, a large number of micropores and mesopores, and a large specific surface area. Therefore, compared with the existing silica, porous silica has good adsorption characteristics and can adsorb organic dyes in its pore structure. This not only makes the obtained aluminum pigment present colorful colors, but also makes the aluminum pigment have good corrosion resistance, high gloss and good dispersibility, and can be widely used in coatings, inks and other industries.

[0009] Preferably, the organic dye is a reactive dye, a direct dye or an acid dye containing a sulfonic acid group, a carboxylic acid group or a phosphoric acid group.

[0010] Preferably, the porous silica is amino-functional porous silica.

[0011] In the present invention, amino-functionalized porous silica has amino-active groups on its surface, and its polar effect can enhance the polarity of the porous silica pore surface, so that hydrogen bonds or electrostatic bonds can be formed with the aforementioned active dyes, direct dyes or acid dyes containing sulfonic acid groups, carboxylic acid groups or phosphoric acid groups, which not only enhances the adsorption effect of porous silica on organic dyes, but also enhances the fixation of organic dyes in the porous silica pores, thereby overcoming the disadvantage of poor stability of colored aluminum pigments obtained by simple physical adsorption in solvents.

[0012] Preferably, the method further comprises an aqueous acrylic resin layer which is coated on the surface of the porous silica and encapsulates the organic dye in the pores of the porous silica.

[0013] In the present invention, the water-based acrylic resin layer is coated on the surface of the porous silica, which can further block the contact between the aluminum particles and the external environment and enhance its corrosion resistance; on the other hand, it can also play a good protective role on the organic dye and enhance its color fastness; furthermore, it can improve the compatibility of the aluminum pigment with the water-based matrix and improve the dispersibility of the aluminum pigment in the water-based matrix, thereby simultaneously meeting the requirements of corrosion resistance and compatibility with the water-based matrix.

[0014] The present invention also provides a method for preparing the above-mentioned water-based colored aluminum pigment, comprising the following steps:

[0015] S1, coating the surface of flaky aluminum particles with porous silica to obtain porous silica-coated aluminum pigment;

[0016] S2. After mixing the porous silica-coated aluminum pigment with an organic dye, the organic dye is adsorbed into the pores of the porous silica to obtain the water-based colored aluminum pigment.

[0017] In the present invention, the flaky aluminum particles are first modified so that a porous silica coating layer is deposited on the surface of the flaky aluminum particles. While exerting the corrosion resistance effect, the adsorption effect of the coating layer is utilized to adsorb organic dyes to color the surface of the aluminum pigment, and finally the water-based colored aluminum pigment is obtained.

[0018] Preferably, in step S1, the “coating the surface of the flaky aluminum particles with porous silica” specifically comprises: reacting the flaky aluminum particles with a porous template and a silicon source;

[0019] Preferably, the porous template is hexadecyltrimethylammonium bromide or tetrapropylammonium hydroxide, and the silicon source is at least one of methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, butyl orthosilicate or pentyl orthosilicate.

[0020] In the present invention, porous silica is synthesized by a template method. By selecting hexadecyltrimethylammonium bromide or tetrapropylammonium hydroxide as a template agent, porous silica with rich pore structure and excellent adsorption performance is synthesized on the surface of flaky aluminum particles.

[0021] Preferably, in step S1, after "coating the surface of the flaky aluminum particles with porous silica", the step further includes: coupling the porous silica-coated aluminum pigment with an aminosilane coupling agent to obtain an amino-functional porous silica-coated aluminum pigment;

[0022] Preferably, the aminosilane coupling agent is at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane or 3-aminopropylmethyltriethoxysilane.

[0023] In the present invention, after the active hydroxyl groups on the surface of the porous silica-coated aluminum particles are modified by an aminosilane coupling agent, amino groups are introduced into the surface of the porous silica-coated aluminum particles.

[0024] Preferably, in step S2, the “mixing the porous silica-coated aluminum pigment with an organic dye” specifically comprises: adding the porous silica-coated aluminum pigment and the organic dye into water or an alcohol solvent and performing ultrasonic vibration;

[0025] Preferably, the alcohol solvent is at least one of methanol, ethanol, propanol, butanol or isopropanol.

[0026] Preferably, in step S2, after “mixing the porous silica-coated aluminum pigment with an organic dye”, the method further comprises: subjecting the aluminum pigment adsorbed with the organic dye in the pores of the porous silica to an esterification or amidation reaction with 3-chloropropionyl chloride, and then subjecting the aluminum pigment to a copolymerization reaction with dimethylaminoethyl acrylate, ethyl acrylate and hydroxyethyl methacrylate;

[0027] Preferably, the mass ratio of dimethylaminoethyl acrylate, ethyl acrylate and hydroxyethyl methacrylate is 10:1-3:2-4.

[0028] In the present invention, hydroxyl or amino active groups exist on the surface of the aluminum pigment adsorbing the organic dye in the pores of the porous silica, and the hydroxyl or amino active groups can be subjected to esterification or amidation reaction with 3-chloropropionyl chloride, so that the chloroethyl group is grafted onto the surface of the porous silica. Afterwards, when copolymerization reaction is carried out with dimethylaminoethyl acrylate, ethyl acrylate and hydroxyethyl methacrylate, the chloroethyl group and the monomers of dimethylaminoethyl acrylate can undergo nucleophilic substitution reaction to form a quaternary ammonium salt, and the positive electric property of the quaternary ammonium salt can form electrostatic adsorption with the negatively charged organic dye containing sulfonic acid group, carboxylic acid group or phosphoric acid group, so that the organic dye can be further fixed on the one hand, and a water-based acrylic resin layer can be generated through copolymerization reaction, and electrostatic adsorption is formed between the water-based acrylic resin layer and the pigment, which makes the encapsulation effect of the water-based acrylic resin layer more firm and can also prevent the encapsulation layer from falling off from the organic pigment, thereby ensuring further enhancement of the color fixing effect.

[0029] Beneficial effects of the present invention:

[0030] The present invention proposes a water-based colored aluminum pigment and a preparation method thereof and application in coatings or inks. Silicon dioxide with rich micro-mesoporous three-dimensional channel structure is deposited on the surface of aluminum particles, so that the aluminum pigment is colored by adsorbing organic dye molecules in the dyeing liquid. Thereafter, the aluminum pigment is coated by functional groups, organic dye selection and coating layer, thereby solving the defect that the colored aluminum pigment prepared by physical coating or physical deposition methods is unstable in solvents. The aluminum pigment of the present invention has brilliant colors, good corrosion resistance, high gloss and good dispersibility, and will be widely used in coatings, inks and other industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a SEM image of the porous silica-coated aluminum pigment described in Example 1;

[0032] Figure 2 This is a product picture of the water-based colored aluminum pigment described in Example 1;

[0033] Figure 3 This is a schematic structural diagram of the water-based colored aluminum pigment described in Example 5. DETAILED DESCRIPTION

[0034] Hereinafter, the present invention will describe the technical solution in detail through specific embodiments, but it should be clearly stated that these embodiments are for illustration only and are not to be construed as limiting the scope of the present invention. Example 1

[0035] This embodiment provides a water-based colored aluminum pigment, including flaky aluminum particles, porous silica coated on the surface of the flaky aluminum particles, and an organic dye adsorbed in the pores of the porous silica.

[0036] The above-mentioned water-based colored aluminum pigment is prepared by the following method:

[0037] (1) 15 parts by weight of commercially available solvent-based aluminum pigment (solid content of 75%) was added to 50 parts by weight of anhydrous ethanol, heated to 40°C and stirred for 3 hours, and filtered to obtain washed flaky aluminum particles (D50 particle size of 40 μm, aspect ratio of 150);

[0038] (2) adding the washed flaky aluminum particles to 100 parts by mass of cyclohexane and dispersing them evenly, then adding 10 parts by mass of tetraethyl orthosilicate and stirring to obtain an oil phase; adding 1 part by mass of hexadecyltrimethylammonium bromide to 200 parts by mass of water and stirring to obtain an aqueous phase; dropping the oil phase into the aqueous phase, emulsifying at a rate of 10,000 r / min for 20 min, adjusting the pH value of the solution to 9, heating to 50° C. and stirring to react for 8 h, centrifuging, washing with deionized water and anhydrous ethanol three times respectively, and drying to obtain a porous silica-coated aluminum pigment;

[0039] (3) The porous silica-coated aluminum pigment is added to 50 parts by weight of an aqueous solution containing 0.5 parts by weight of Direct Lake Blue 5B, and ultrasonically vibrated at 300 W for 12 h at room temperature. After centrifugal separation, the mixture is dried to obtain the water-based colored aluminum pigment.

[0040] Figure 1 This is the SEM image of the porous silica-coated aluminum pigment described in this embodiment, referring to Figure 1 It can be seen that the surface of the flaky aluminum particles is coated with loose and porous silicon dioxide; Figure 2 This is a product diagram of the water-based colored aluminum pigment described in this embodiment, refer to Figure 2 It can be seen that the water-based colored aluminum pigment has a blue appearance. Example 2

[0041] This embodiment provides a water-based colored aluminum pigment, including flaky aluminum particles, porous silica coated on the surface of the flaky aluminum particles, and an organic dye adsorbed in the pores of the porous silica.

[0042] The above-mentioned water-based colored aluminum pigment is prepared by the following method:

[0043] (1) 15 parts by weight of commercially available solvent-based aluminum pigment (solid content of 75%) was added to 50 parts by weight of anhydrous ethanol, heated to 40°C and stirred for 3 hours, and filtered to obtain washed flaky aluminum particles (D50 particle size of 40 μm, aspect ratio of 150);

[0044] (2) adding the washed flaky aluminum particles to 100 parts by mass of cyclohexane and dispersing them evenly, then adding 10 parts by mass of tetraethyl orthosilicate and stirring to obtain an oil phase; adding 1 part by mass of hexadecyltrimethylammonium bromide to 200 parts by mass of water and stirring to obtain an aqueous phase; dropping the oil phase into the aqueous phase, emulsifying at a rate of 10,000 r / min for 20 min, adjusting the pH value of the solution to 9, heating to 50° C. and stirring to react for 8 h, centrifuging, washing with deionized water and anhydrous ethanol three times respectively, and drying to obtain a porous silica-coated aluminum pigment;

[0045] (3) The porous silica-coated aluminum pigment is added to 50 parts by weight of an aqueous solution containing 0.5 parts by weight of active yellow K-RN, and ultrasonically vibrated at 300 W for 12 h at room temperature. After centrifugal separation, the mixture is dried to obtain the water-based colored aluminum pigment. Example 3

[0046] This embodiment provides a water-based colored aluminum pigment, including flaky aluminum particles, porous silica coated on the surface of the flaky aluminum particles, and an organic dye adsorbed in the pores of the porous silica.

[0047] The above-mentioned water-based colored aluminum pigment is prepared by the following method:

[0048] (1) 15 parts by weight of commercially available solvent-based aluminum pigment (solid content of 75%) was added to 50 parts by weight of anhydrous ethanol, heated to 40°C and stirred for 3 hours, and filtered to obtain washed flaky aluminum particles (D50 particle size of 40 μm, aspect ratio of 150);

[0049] (2) adding the washed flaky aluminum particles to 100 parts by mass of cyclohexane and dispersing them uniformly, then adding 10 parts by mass of tetraethyl orthosilicate and stirring to obtain an oil phase; adding 1 part by mass of hexadecyltrimethylammonium bromide to 200 parts by mass of water and stirring to obtain an aqueous phase; dropping the oil phase into the aqueous phase, emulsifying at a rate of 10,000 r / min for 20 min, adjusting the pH value of the solution to 9, heating to 50° C. and stirring to react for 8 h, centrifuging, washing with deionized water and anhydrous ethanol three times respectively, and drying to obtain a porous silica-coated aluminum pigment;

[0050] (3) adding the porous silica-coated aluminum pigment to 50 parts by mass of anhydrous ethanol, and then adding 15 parts by mass of 3-aminopropyltriethoxysilane, stirring and reacting for 12 hours, centrifuging, washing with ethanol, and drying to obtain an amino-functional porous silica-coated aluminum pigment;

[0051] (4) The amino-functional porous silica-coated aluminum pigment is added to 50 parts by weight of an aqueous solution containing 0.5 parts by weight of Direct Lake Blue 5B, and ultrasonically vibrated at a power of 300 W for 12 h at room temperature. After centrifugation and drying, the water-based colored aluminum pigment is obtained. Example 4

[0052] This embodiment provides a water-based colored aluminum pigment, including flaky aluminum particles, porous silica coated on the surface of the flaky aluminum particles, an organic dye adsorbed in the pores of the porous silica, and a water-based acrylic resin layer coated on the surface of the porous silica and encapsulating the organic dye in the pores of the porous silica.

[0053] The above-mentioned water-based colored aluminum pigment is prepared by the following method:

[0054] (1) 15 parts by weight of commercially available solvent-based aluminum pigment (solid content of 75%) was added to 50 parts by weight of anhydrous ethanol, heated to 40°C and stirred for 3 hours, and filtered to obtain washed flaky aluminum particles (D50 particle size of 40 μm, aspect ratio of 150);

[0055] (2) adding the washed flaky aluminum particles to 100 parts by mass of cyclohexane and dispersing them uniformly, then adding 10 parts by mass of tetraethyl orthosilicate and stirring to obtain an oil phase; adding 1 part by mass of hexadecyltrimethylammonium bromide to 200 parts by mass of water and stirring to obtain an aqueous phase; dropping the oil phase into the aqueous phase, emulsifying at a rate of 10,000 r / min for 20 min, adjusting the pH value of the solution to 9, heating to 50° C. and stirring to react for 8 h, centrifuging, washing with deionized water and anhydrous ethanol three times respectively, and drying to obtain a porous silica-coated aluminum pigment;

[0056] (3) adding the porous silica-coated aluminum pigment to 50 parts by mass of anhydrous ethanol, and then adding 15 parts by mass of 3-aminopropyltriethoxysilane, stirring and reacting for 12 hours, centrifuging, washing with ethanol, and drying to obtain an amino-functional porous silica-coated aluminum pigment;

[0057] (4) adding the amino-functional porous silica-coated aluminum pigment to 50 parts by weight of an aqueous solution containing 0.5 parts by weight of Direct Lake Blue 5B, ultrasonically vibrating at 300 W for 12 h at room temperature, centrifuging, and drying to obtain an aluminum pigment adsorbing an organic dye in the pores of the porous silica;

[0058] (5) The aluminum pigment with organic dye adsorbed in the pores of the porous silica is added to 50 parts by mass of anhydrous toluene, and then 5 parts by mass of triethylamine and 1 part by mass of 3-chloropropionyl chloride are added in sequence, and the mixture is stirred at room temperature for 12 hours, centrifuged, washed, and evenly dispersed in 50 parts by mass of water containing 2 parts by mass of dimethylaminoethyl acrylate. After ultrasonic vibration for 2 hours, 0.5 parts by mass of ethyl acrylate, 0.7 parts by mass of hydroxyethyl methacrylate, 0.02 parts by mass of potassium persulfate and 0.01 parts by mass of sodium bisulfite are added, heated to 40°C, stirred for 5 hours, centrifuged, washed three times with anhydrous ethanol, and dried to obtain the water-based colored aluminum pigment.

[0059] Figure 3 The schematic diagram of the structure of the water-based colored aluminum pigment described in this embodiment is shown in FIG. Figure 3 It can be seen that the core of the water-based colored aluminum pigment is flaky aluminum particles, the surface is coated with porous silica, the organic dye is adsorbed in the pores of the porous silica, and the outer layer of the porous silica is coated with a water-based acrylic resin layer.

[0060] Comparative Example 1

[0061] This comparative example proposes a water-based colored aluminum pigment, which is prepared by the following method:

[0062] (1) 15 parts by weight of commercially available solvent-based aluminum pigment (solid content of 75%) was added to 50 parts by weight of anhydrous ethanol, heated to 40°C and stirred for 3 hours, and filtered to obtain washed flaky aluminum particles (D50 particle size of 40 μm, aspect ratio of 150);

[0063] (2) adding the washed flaky aluminum particles to 100 parts by mass of water and dispersing them evenly, then adding 10 parts by mass of ethyl orthosilicate and stirring to mix them evenly, adjusting the pH value of the solution to 9, heating to 50° C. and stirring to react for 8 hours, centrifuging, washing with deionized water and anhydrous ethanol three times respectively, and drying to obtain a silica-coated aluminum pigment;

[0064] (3) The above-mentioned silica-coated aluminum pigment was added to 50 parts by weight of an aqueous solution containing 0.5 parts by weight of Direct Lake Blue 5B, and ultrasonically vibrated at a power of 300 W for 12 hours at room temperature. After centrifugation and drying, the water-based colored aluminum pigment was obtained.

[0065] Comparative Example 2

[0066] This comparative example proposes a water-based colored aluminum pigment, which is prepared by the following method:

[0067] (1) 15 parts by weight of commercially available solvent-based aluminum pigment (solid content of 75%) was added to 50 parts by weight of anhydrous ethanol, heated to 40°C and stirred for 3 hours, and filtered to obtain washed flaky aluminum particles (D50 particle size of 40 μm, aspect ratio of 150);

[0068] (2) adding the washed flaky aluminum particles to 100 parts by mass of cyclohexane and dispersing them evenly, then adding 10 parts by mass of tetraethyl orthosilicate and stirring to obtain an oil phase; adding 1 part by mass of hexadecyltrimethylammonium bromide to 200 parts by mass of water and stirring to obtain an aqueous phase; dropping the oil phase into the aqueous phase, emulsifying at a rate of 10,000 r / min for 20 min, adjusting the pH value of the solution to 9, heating to 50° C. and stirring to react for 8 h, centrifuging, washing with deionized water and anhydrous ethanol three times respectively, and drying to obtain a porous silica-coated aluminum pigment;

[0069] (3) adding the porous silica-coated aluminum pigment to 50 parts by mass of anhydrous ethanol, and then adding 15 parts by mass of 3-aminopropyltriethoxysilane, stirring and reacting for 12 hours, centrifuging, washing with ethanol, and drying to obtain an amino-functional porous silica-coated aluminum pigment;

[0070] (4) adding the amino-functional porous silica-coated aluminum pigment to 50 parts by weight of an aqueous solution containing 0.5 parts by weight of Direct Lake Blue 5B, ultrasonically vibrating at 300 W for 12 h at room temperature, centrifuging, and drying to obtain an aluminum pigment adsorbing an organic dye in the pores of the porous silica;

[0071] (5) The aluminum pigment with organic dye adsorbed in the pores of the porous silica is added to 50 parts by mass of water containing 2 parts by mass of dimethylaminoethyl acrylate and dispersed evenly. After ultrasonic vibration for 2 hours, 0.5 parts by mass of ethyl acrylate, 0.7 parts by mass of hydroxyethyl methacrylate, 0.02 parts by mass of potassium persulfate and 0.01 parts by mass of sodium bisulfite are added. The mixture is heated to 40° C. and stirred for reaction for 5 hours. The mixture is centrifuged, washed three times with anhydrous ethanol and dried to obtain the water-based colored aluminum pigment.

[0072] The aluminum pigment described in the embodiment or comparative example was subjected to a corrosion resistance test. Specifically, the corrosion resistance test was performed according to the requirements of "Water-based Aluminum Slurry HG / T2456.5-2016". 1 g of the aluminum pigment described in the embodiment or comparative example was added to a 1 mol / L hydrochloric acid solution or a 1 mol / L sodium hydroxide solution, and heated at 100° C. for 2 h. The hydrogen production was tested. The results are shown in Table 1 below.

[0073]

[0074] As shown in Table 1 above, the amount of hydrogen evolution in Examples 1-4 is very small, indicating that the water-based aluminum pigment of the present invention has excellent acid, alkali and other corrosion resistance; and the amount of hydrogen evolution in Example 3 is reduced compared with Example 1, indicating that after the porous silica is modified by the amino functional group, the adsorption effect of the organic dye in the pores of the porous silica can be enhanced, thereby further improving the corrosion resistance of the water-based aluminum pigment; similarly, the amount of hydrogen evolution in Example 4 shows that it is basically unreactive, indicating that the acrylic resin layer can be effectively coated on the surface of the porous silica, further improving the corrosion resistance of the water-based aluminum pigment; in addition, compared with Example 4, in Comparative Example 2, since no amidation reaction is performed with 3-chloropropionyl chloride, no chloroethyl group is grafted, and when the acrylic resin is subsequently polymerized in situ, due to the absence of electrostatic adsorption effect, the effect of the water-based acrylic resin layer coating the aluminum pigment is reduced, and the corrosion resistance is also weakened.

[0075] The hue analysis of the aluminum pigment after coloring in the embodiment or comparative example is as follows: Indicates brightness, Represents the range from magenta to green (where positive values ​​indicate the red direction and negative values ​​indicate the green direction), Represents the range from yellow to blue (where positive values ​​indicate the yellow direction and negative values ​​indicate the blue direction). is the color saturation, and the results are shown in Table 2 below;

[0076] As shown in Table 2 above, Examples 1, 3, and 4 are bluish green, and Example 2 is yellowish green, which indicates that the organic dye is effectively attached to the surface of the aluminum particles, and the color saturation values ​​of Examples 3 and 4 are uniformly greater than those of Example 1, indicating that both functional group modification and polymer coating can tightly encapsulate the organic dye on the surface of the aluminum particles, further increasing the color performance.

[0077] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A water-based colored aluminum pigment, characterized in that: It includes flaky aluminum particles, porous silicon dioxide coated on the surface of the flaky aluminum particles, and an organic dye adsorbed in the pores of the porous silicon dioxide; The organic dye is a reactive dye, direct dye or acid dye containing a sulfonic acid group, a carboxylic acid group or a phosphoric acid group; The water-based colored aluminum pigment is prepared by the following preparation method: S1, coating the surface of flaky aluminum particles with porous silica to obtain porous silica-coated aluminum pigment; S2, mixing the porous silica-coated aluminum pigment with an organic dye, and allowing the organic dye to adsorb into the pores of the porous silica to obtain the water-based colored aluminum pigment; In step S1, after "coating the surface of the flaky aluminum particles with porous silica", the method further includes: coupling the porous silica-coated aluminum pigment with an aminosilane coupling agent to obtain an amino-functional porous silica-coated aluminum pigment; In step S2, after "mixing the porous silica-coated aluminum pigment with an organic dye", the method further includes: esterifying or amidating the aluminum pigment adsorbed with the organic dye in the pores of the porous silica with 3-chloropropionyl chloride, and then copolymerizing with dimethylaminoethyl acrylate, ethyl acrylate and hydroxyethyl methacrylate.

2. The water-based colored aluminum pigment according to claim 1, characterized in that: The porous silica is amino-functional porous silica.

3. The water-based colored aluminum pigment according to claim 1, characterized in that: The invention also comprises a water-based acrylic resin layer which is coated on the surface of the porous silica and encapsulates the organic dye in the pores of the porous silica.

4. A method for preparing the water-based colored aluminum pigment according to any one of claims 1 to 3, characterized in that: The steps include: S1, coating the surface of flaky aluminum particles with porous silica to obtain porous silica-coated aluminum pigment; S2, mixing the porous silica-coated aluminum pigment with an organic dye, and allowing the organic dye to adsorb into the pores of the porous silica to obtain the water-based colored aluminum pigment; In step S1, after "coating the surface of the flaky aluminum particles with porous silica", the method further includes: coupling the porous silica-coated aluminum pigment with an aminosilane coupling agent to obtain an amino-functional porous silica-coated aluminum pigment; In step S2, after "mixing the porous silica-coated aluminum pigment with an organic dye", the method further includes: esterifying or amidating the aluminum pigment adsorbed with the organic dye in the pores of the porous silica with 3-chloropropionyl chloride, and then copolymerizing with dimethylaminoethyl acrylate, ethyl acrylate and hydroxyethyl methacrylate.

5. The method for preparing the water-based colored aluminum pigment according to claim 4, characterized in that: In step S1, the "coating the surface of the flaky aluminum particles with porous silica" specifically includes: reacting the flaky aluminum particles with a porous template and a silicon source.

6. The method for preparing the water-based colored aluminum pigment according to claim 5, characterized in that: The porous template is hexadecyltrimethylammonium bromide or tetrapropylammonium hydroxide, and the silicon source is at least one of methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, butyl orthosilicate or pentyl orthosilicate.

7. The method for preparing the water-based colored aluminum pigment according to claim 4 or 5, characterized in that: The aminosilane coupling agent is at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane or 3-aminopropylmethyltriethoxysilane.

8. The method for preparing the water-based colored aluminum pigment according to claim 4 or 5, characterized in that: In step S2, the "mixing the porous silica-coated aluminum pigment with an organic dye" specifically includes: adding the porous silica-coated aluminum pigment and the organic dye into water or an alcohol solvent and performing ultrasonic vibration.

9. The method for preparing the water-based colored aluminum pigment according to claim 8, characterized in that: The alcohol solvent is at least one of methanol, ethanol, propanol, butanol or isopropanol.

10. The method for preparing the water-based colored aluminum pigment according to claim 4 or 5, characterized in that: The mass ratio of the dimethylaminoethyl acrylate, ethyl acrylate and hydroxyethyl methacrylate is 10:1-3:2-4.

11. Use of the colored aluminum pigment according to any one of claims 1 to 3 or the colored aluminum pigment prepared by the preparation method according to any one of claims 4 to 10 in coatings or inks.

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