Aqueous nano-dispersion for colorants and method for its preparation

Abstract

The present application belongs to the technical field of color paste dispersant, and particularly relates to a dispersant for water-based nano color paste and a preparation method thereof. In the present application, inorganic two-dimensional nanosheets are used as rigid carriers, amino groups are introduced through amino-containing silane coupling agents, a step-by-step grafting strategy is adopted, carboxyl groups in the anchoring group are activated by EDC / NHS first, and then react with the amino-functionalized nanosheets to form amide bonds, and then hydrophilic solvent chains terminated by carboxyl groups are grafted to obtain a bifunctional grafting dispersant; wherein the two-dimensional nanosheets are montmorillonite or graphene oxide, the anchoring group is a carboxylic acid compound containing an aromatic ring, and strong adsorption is achieved on the surface of the pigment through π-π stacking; the solvent chains extend into the aqueous phase to provide steric hindrance; the rigid nanosheet skeleton prevents the collapse of the solvent chains; the dispersant prepared by the method has high dispersing performance in the water-based nano color paste, can realize nano-level dispersion of pigment particles, and has excellent storage stability.

Description

Technical Field

[0001] This invention belongs to the field of pigment dispersant technology, specifically relating to a water-based nano pigment dispersant and its preparation method. Background Technology

[0002] Water-based nano-pigment pastes are stable suspension systems formed by dispersing pigment particles in an aqueous phase through physical or chemical means. They are widely used in coatings, inks, inkjet printing, textile printing and dyeing, and other fields. Compared with solvent-based pigment pastes, water-based pigment pastes have environmental advantages and are in line with the current development direction of green industry. However, due to the large specific surface area and high surface energy of pigment particles, they are prone to agglomeration and sedimentation in aqueous media. Therefore, the selection and design of dispersants has become the core technical challenge in the preparation of water-based pigment pastes.

[0003] The working principle of dispersants is that anchoring groups adsorb onto the surface of pigment particles, while solvation chains extend into the aqueous phase to provide steric hindrance, thereby preventing the re-agglomeration of pigment particles. Currently, commonly used dispersants in water-based pigment pastes mainly fall into three categories: inorganic dispersants, small-molecule organic dispersants, and polymeric dispersants. Inorganic dispersants and small-molecule organic dispersants primarily rely on electrostatic repulsion to achieve dispersion stability, but the adsorption force between the anchoring groups and the pigment surface is relatively weak, making them prone to desorption and causing the dispersed pigment particles to re-flocculate. In contrast, polymeric dispersants achieve a more stable dispersion effect through multi-point adsorption of anchoring groups onto the pigment surface and steric hindrance provided by solvation chains.

[0004] Currently, dispersants have been widely used in the field of pigment dispersion. However, existing technologies still have many shortcomings: First, the anchoring groups of conventional dispersants are mostly ionic groups such as carboxyl and sulfonic acid groups, which mainly rely on electrostatic adsorption, resulting in poor salt resistance and pH adaptability, and poor storage stability. Second, the anchoring method of existing dispersants is mostly point adsorption, which has limited anchoring strength, and the adsorption layer is easily destroyed during high-speed grinding or long-term storage. Third, the solvation chain of flexible polymer dispersants is prone to collapse under shearing, reducing steric hindrance efficiency. Therefore, developing a water-based nano-color paste dispersant with good dispersion performance, high anchoring strength, stable steric hindrance, and high storage stability has important research significance and application value. Summary of the Invention

[0005] The purpose of this invention is to provide a dispersant for aqueous nano-color pastes and its preparation method, so as to solve the above-mentioned technical problems.

[0006] To achieve the above-mentioned technical objectives, the technical solution of the present invention is as follows:

[0007] A method for preparing a dispersant for aqueous nano-color pastes includes the following steps:

[0008] S1. Aminated inorganic two-dimensional nanosheets are added to deionized water and ultrasonically dispersed to obtain a carrier dispersion.

[0009] S2. Dissolve the anchoring group reagent in anhydrous ethanol, add EDC·HCl and NHS, activate at room temperature for 20~40 min, add to the carrier dispersion, and react at 20~25℃ in a nitrogen atmosphere for 4~6 h to obtain the anchoring group modified carrier dispersion.

[0010] S3. Dissolve the solvation chain reagent in anhydrous ethanol, add EDC·HCl and NHS, activate at room temperature for 20~40 min, add to the anchoring group modified carrier dispersion, and react at 20~25℃ under nitrogen atmosphere for 12~24 h.

[0011] S4. After the reaction is complete, centrifuge and collect the precipitate. Wash the precipitate with anhydrous ethanol and deionized water in sequence, freeze dry, and obtain a water-based nano-color paste dispersant.

[0012] As a further improvement, in step S1, the preparation method of aminated inorganic two-dimensional nanosheets is as follows: take the exfoliated two-dimensional nanosheets and disperse them in an ethanol solution, sonicate them to obtain a dispersion; add an aminosilane coupling agent, adjust the pH to 4.5~5.0, stir and react for 10~16 h at 50~65℃ under a nitrogen atmosphere, centrifuge, collect the precipitate, wash and dry it to obtain aminated inorganic two-dimensional nanosheets.

[0013] As a further improvement, the preparation method of the exfoliated two-dimensional nanosheets is as follows: montmorillonite or graphene oxide is added to deionized water, stirred for 6-12 hours, sonicated at 500-700W for 1.5-4 hours, during which the temperature is kept below 40℃, centrifuged at 2000-4000rpm for 10-20 minutes, the supernatant is collected, centrifuged at 10000-14000rpm for 20-40 minutes, the precipitate is collected, washed, and freeze-dried to obtain the exfoliated two-dimensional nanosheets.

[0014] As a further improvement, in step S2, the anchoring group reagent is any one of 1-pyrenepropionic acid, 1-pyrenebutyric acid, 9-anthracarboxylic acid, 1-naphthoic acid, 2-naphthoic acid, or biphenyl-4-carboxylic acid.

[0015] As a further improvement, in step S3, the solvation chain reagent is any one of polyethylene glycol monomethyl ether carboxylic acid, polypropylene glycol monomethyl ether carboxylic acid, polyethylene glycol-polypropylene glycol block copolymer monomethyl ether carboxylic acid, polyethylene glycol dicarboxylic acid, or polyglycerol monomethyl ether carboxylic acid.

[0016] As a further improvement, in step S2, the molar ratio of carboxylic acid, EDC·HCl and NHS in the anchoring group reagent is 1:1~1.2:1~1.2; in step S3, the molar ratio of carboxylic acid, EDC·HCl and NHS in the solvation chain reagent is 1:1~1.5:1~1.5.

[0017] As a further improvement, the mass ratio of the aminated inorganic two-dimensional nanosheets, the anchoring group reagent, and the solvated chain reagent is 1:0.2~0.8:0.5~1.

[0018] As a further improvement, the montmorillonite is one of sodium-based montmorillonite, calcium-based montmorillonite, or magnesium-based montmorillonite.

[0019] The present invention also provides a dispersant for aqueous nano-color pastes.

[0020] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0021] This invention provides a water-based nano-color paste dispersant and its preparation method. Inorganic two-dimensional nanosheets are used as a rigid carrier, and aromatic anchoring groups and hydrophilic polyether solvation chains are simultaneously grafted via covalent bonds, constructing a unique rigid framework combined with a bifunctional grafted structure. The aromatic ring structure in the anchoring group can form a strong π-π stacking interaction with the aromatic ring system on the surface of organic pigments, achieving an improvement from the point adsorption of traditional dispersants to planar flat anchoring, significantly increasing the binding strength between the dispersant and pigment particles. Simultaneously, the rigid planar structure of the two-dimensional nanosheets effectively prevents the solvation chains from collapsing during high-speed shearing or storage, maintaining the integrity and effectiveness of the steric hindrance layer. This strong anchoring and high steric hindrance create a synergistic effect, enabling the dispersant of this invention to form a stable and dense adsorption layer on the surface of pigment particles, fundamentally solving the technical problem of the difficulty in simultaneously achieving anchoring strength and steric hindrance efficiency in existing dispersants.

[0022] This invention employs a stepwise grafting strategy and a one-pot activation process, which has the advantages of a clear synthesis route, simple operation, and mild reaction conditions. Stepwise grafting ensures that small molecule anchoring groups preferentially occupy the active sites on the surface of two-dimensional nanosheets, avoiding the problem of large molecule solvated chains hindering the approach of anchoring groups due to steric hindrance during simultaneous grafting, thereby achieving dual optimization of anchoring density and solvated chain grafting density.

[0023] The dispersant of this invention does not rely on electrostatic adsorption for anchoring, thus exhibiting excellent salt resistance and pH universality. It can maintain stable dispersion performance under different water quality conditions, broadening its application range in coatings, inks, inkjet printing and other fields. Attached Figure Description

[0024] Figure 1This is an image of the Fourier transform infrared spectrum of the aminated montmorillonite prepared in Example 1;

[0025] Figure 2 This is an image of the Fourier transform infrared spectrum of the dispersant for the aqueous nano-color paste prepared in Example 1. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or manufacturer's conditions shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0027] Example 1: A method for preparing a dispersant for aqueous nano-color pastes, comprising the following steps:

[0028] 1. Add 5.0 g of sodium montmorillonite to 500 mL of deionized water and stir magnetically at 500 rpm for 12 h to allow the montmorillonite to fully swell. Transfer to a beaker and sonicate using an ultrasonic cell disruptor at 600 W for 2 h (3 s working / 3 s resting), keeping the beaker in an ice-water bath to maintain a temperature below 40 °C. After sonication, centrifuge the dispersion at 3000 rpm for 10 min and collect the supernatant. Centrifuge the supernatant at 12000 rpm for 30 min and collect the precipitate. Wash the precipitate with deionized water twice. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry at -50 °C for 48 h to obtain exfoliated montmorillonite nanosheets.

[0029] 2. Take 1.0 g of exfoliated montmorillonite nanosheets and disperse them in 100 mL of anhydrous ethanol / deionized water mixed solvent (volume ratio 9:1). Sonicate the solution at 300 W for 30 min (3 s working, 3 s rest) to obtain a dispersion. Add 0.5 g of KH550 (3-aminopropyltriethoxysilane) to the dispersion, adjust the pH to 4.5 with acetic acid, and react at 500 rpm for 12 h under nitrogen protection at 60 °C. After the reaction, centrifuge at 10000 rpm for 10 min and collect the precipitate. Wash the precipitate with anhydrous ethanol, centrifuge at 10000 rpm for 10 min, and repeat the washing three times. Dry the washed precipitate in a vacuum drying oven at 60 °C for 12 h to obtain aminated montmorillonite. The chemical reaction formula for this step is as follows:

[0030] ;

[0031] The Fourier transform infrared spectrum of the aminated montmorillonite prepared in this embodiment is shown in the image below. Figure 1 As shown; from Figure 1 It can be seen from this that at 3600cm -1 The absorption peak at approximately 3400 cm⁻¹ represents the stretching vibration of unreacted hydroxyl groups remaining in the montmorillonite structure. -1 The peak at 2900 cm⁻¹ is a superposition of the hydroxyl stretching vibration peak of the interlayer adsorbed water and the amino stretching vibration peak of the silane coupling agent. -1 The absorption peak for the stretching vibration of the methylene group is located at approximately 1650 cm⁻¹. -1 The absorption peak at 950 cm⁻¹ is the bending vibration of amino groups. -1 The absorption peak at 520 cm⁻¹ is the aluminum hydroxyl group absorption peak. -1 The absorption peak at this point represents the silicon-oxygen bond; the above results indicate that the silane coupling agent has been successfully grafted onto the surface of montmorillonite nanosheets.

[0032] 3. Take 0.8 g of aminated montmorillonite, add it to 50 mL of deionized water, and ultrasonically disperse it at 300 W for 20 min (3 s working / 3 s intermittent) to obtain a carrier dispersion; weigh 1.0 mmol (0.28 g) of 1-pyrenebutyric acid, dissolve it in 20 mL of anhydrous ethanol, add 1.1 mmol EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and 1.1 mmol NHS (N-hydroxysuccinimide), stir and activate at room temperature for 30 min, add it to the carrier dispersion, and react under nitrogen atmosphere at 25 °C with stirring at 400 rpm for 5 h to obtain an anchoring group modified carrier dispersion; weigh 1.0 mmol (0.75 g) of polyethylene glycol monomethyl ether carboxylic acid (Mw=750), dissolve it in 20 mL of anhydrous ethanol, add 1.3 mmol EDC·HCl and 1.3 mmol NHS was activated at room temperature with stirring for 30 min, then added to the anchoring group modified carrier dispersion. The mixture was reacted at 400 rpm for 20 h under a nitrogen atmosphere at 25 °C. After the reaction, the reaction solution was centrifuged at 10000 rpm for 10 min, and the precipitate was collected and washed with anhydrous ethanol, repeating the washing process three times. Then, it was washed with deionized water, repeating the washing process three times. The washed precipitate was transferred to a lyophilization bottle and freeze-dried at -50 °C for 48 h to obtain an aqueous nano-color paste dispersant. The chemical reaction formula for this step is as follows:

[0033] ;

[0034] The Fourier transform infrared spectrum of the dispersant for the aqueous nano-color paste prepared in this embodiment is shown in the image below. Figure 2 As shown: From Figure 2 It can be seen from this that 3600cm -1 The absorption peak at 3400 cm⁻¹ represents the unreacted hydroxyl groups remaining in the montmorillonite structure.-1 The peak at 2850 cm⁻¹ is the superposition peak of the hydroxyl stretching vibration of interlayer adsorbed water and the NH in the amide bond. -1 The absorption peak of the methylene group is at 1600 cm⁻¹. -1 The absorption peak at 1550 cm⁻¹ is the skeletal vibrational absorption peak of the pyrene ring. -1 The peak at 1325 cm⁻¹ is the superposition absorption peak of the NH bending vibration and CN stretching vibration in the amide bond. -1 The absorption peak for the amide bond (CN) is located at 1100 cm⁻¹. -1 The absorption peak at 516 cm⁻¹ represents the ether bond in the polyethylene glycol chain. -1 The absorption peak at this point is the silicon-oxygen bond; the above results indicate that 1-pyrenebutyric acid and polyethylene glycol monomethyl ether carboxylic acid have been successfully grafted onto the surface of aminated montmorillonite via amide bonds.

[0035] Example 2 A method for preparing a dispersant for aqueous nano-color paste, comprising the following steps:

[0036] 1. Add 5.0 g of calcium-based montmorillonite to 500 mL of deionized water and stir magnetically at 500 rpm for 10 h to allow the montmorillonite to fully swell. Transfer to a beaker and sonicate using an ultrasonic cell disruptor at 500 W for 4 h (3 s working / 3 s resting), keeping the beaker in an ice-water bath to maintain a temperature below 40 °C. After sonication, centrifuge the dispersion at 4000 rpm for 15 min and collect the supernatant. Centrifuge the supernatant at 10000 rpm for 40 min and collect the precipitate. Wash the precipitate with deionized water twice. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry at -50 °C for 48 h to obtain exfoliated montmorillonite nanosheets.

[0037] 2. Take 1.0 g of exfoliated montmorillonite nanosheets and disperse them in 100 mL of anhydrous ethanol / deionized water mixed solvent (volume ratio 9:1). Disperse the nanosheets using ultrasonication at 300 W for 30 min (3 s working / 3 s intermittent) to obtain a dispersion. Add 0.5 g of N-aminoethyl-3-aminopropyltriethoxysilane to the dispersion, adjust the pH to 5.0 using acetic acid, and react at 500 rpm for 10 h under nitrogen protection at 65 °C. After the reaction, centrifuge at 10000 rpm for 10 min and collect the precipitate. Wash the precipitate with anhydrous ethanol, centrifuge at 10000 rpm for 10 min, and repeat the washing process three times. Dry the washed precipitate in a vacuum drying oven at 60 °C for 12 h to obtain aminated montmorillonite.

[0038] 3. Take 0.8 g of aminated montmorillonite, add it to 50 mL of deionized water, and ultrasonically disperse it at 300 W for 20 min (3 s working / 3 s intermittent) to obtain a carrier dispersion; weigh 2.33 mmol (0.64 g) of 1-pyrene propionic acid, dissolve it in 20 mL of anhydrous ethanol, add 2.796 mmol EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and 2.796 mmol NHS (N-hydroxysuccinimide), stir and activate at room temperature for 40 min, add it to the carrier dispersion, and react under nitrogen atmosphere at 20 °C with stirring at 400 rpm for 6 h to obtain an anchoring group modified carrier dispersion; weigh 0.8 mmol (0.8 g) of polypropylene glycol monomethyl ether carboxylic acid (Mw=1000), dissolve it in 20 mL of anhydrous ethanol, add 1.2 mmol EDC·HCl and 1.2 mmol NHS was activated by stirring at room temperature for 40 min, then added to the dispersion of the anchoring group modified carrier. The mixture was stirred at 400 rpm for 24 h at 20 °C under a nitrogen atmosphere. After the reaction was completed, the reaction solution was centrifuged at 10,000 rpm for 10 min, and the precipitate was collected and washed with anhydrous ethanol, repeating the washing process 3 times. The precipitate was then washed with deionized water, repeating the washing process 3 times. The washed precipitate was transferred to a freeze-drying bottle and freeze-dried at -50 °C for 48 h to obtain a dispersant for water-based nano-color paste.

[0039] Example 3 A method for preparing a dispersant for aqueous nano-color pastes, comprising the following steps:

[0040] 1. Add 5.0 g of magnesium-based montmorillonite to 500 mL of deionized water and stir magnetically at 500 rpm for 6 h to allow the montmorillonite to fully swell. Transfer to a beaker and sonicate using an ultrasonic cell disruptor at 700 W for 3 h (3 s working / 3 s resting), keeping the beaker in an ice-water bath to maintain a temperature below 40 °C. After sonication, centrifuge the dispersion at 2000 rpm for 20 min and collect the supernatant. Centrifuge the supernatant at 14000 rpm for 20 min and collect the precipitate. Wash the precipitate with deionized water twice. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry at -50 °C for 48 h to obtain exfoliated montmorillonite nanosheets.

[0041] 2. Take 1.0 g of exfoliated montmorillonite nanosheets and disperse them in 100 mL of anhydrous ethanol / deionized water mixed solvent (volume ratio 9:1). Sonicate the mixture at 300 W for 30 min (3 s working / 3 s intermittent) to obtain a dispersion. Add 0.5 g of KH550 (3-aminopropyltriethoxysilane) to the dispersion and adjust the pH to 4.7 with acetic acid. Stir the mixture at 500 rpm for 16 h at 50 °C under nitrogen protection. After the reaction is complete, centrifuge at 10000 rpm for 10 min and collect the precipitate. Wash the precipitate with anhydrous ethanol and centrifuge at 10000 rpm for 10 min, repeating the washing three times. Dry the washed precipitate in a vacuum drying oven at 60 °C for 12 h to obtain aminated montmorillonite.

[0042] 3. Take 1.0 g of aminated montmorillonite, add it to 50 mL of deionized water, and ultrasonically disperse it at 300 W for 20 min (3 s working / 3 s intermittent) to obtain a carrier dispersion; weigh 0.9 mmol (0.2 g) of 9-anthracarboxylic acid, dissolve it in 20 mL of anhydrous ethanol, add 0.9 mmol of EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and 0.9 mmol of NHS (N-hydroxysuccinimide), stir and activate at room temperature for 20 min, add it to the carrier dispersion, and react at 400 rpm for 4 h under nitrogen atmosphere and 23 °C to obtain an anchoring group modified carrier dispersion; weigh 0.167 mmol (0.5 g) of polyethylene glycol-polypropylene glycol block copolymer monomethyl ether carboxylic acid (Mw=3000), dissolve it in 20 mL of anhydrous ethanol, and add 0.167 mmol of EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and 0.9 mmol of NHS (N-hydroxysuccinimide) to obtain an anchoring group modified carrier dispersion; weigh 0.167 mmol (0.5 g) of polyethylene glycol-polypropylene glycol block copolymer monomethyl ether carboxylic acid (Mw=3000), dissolve it in 20 mL of anhydrous ethanol, and add 0.167 mmol of EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) to EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) to EDC·HCl (1-(3-dimethylaminopropyl) EDC·HCl and 0.167 mmol NHS were stirred and activated at room temperature for 20 min. The mixture was then added to the dispersion of the anchoring group modified carrier and reacted at 400 rpm for 12 h under a nitrogen atmosphere at 23 °C. After the reaction was completed, the reaction solution was centrifuged at 10,000 rpm for 10 min, and the precipitate was collected and washed with anhydrous ethanol, repeating the washing process 3 times. The precipitate was then washed with deionized water, repeating the washing process 3 times. The washed precipitate was transferred to a lyophilization bottle and freeze-dried at -50 °C for 48 h to obtain a dispersant for water-based nano-color paste.

[0043] Example 4 A method for preparing a dispersant for aqueous nano-color paste, comprising the following steps:

[0044] 1. Add 5.0 g of graphene oxide to 500 mL of deionized water and stir magnetically at 500 rpm for 6 h to allow the montmorillonite to fully swell. Transfer to a beaker and sonicate using an ultrasonic cell disruptor at 600 W for 1.5 h (3 s working / 3 s resting), keeping the beaker in an ice-water bath to maintain a temperature below 40 °C. After sonication, centrifuge the dispersion at 3000 rpm for 10 min and collect the supernatant. Centrifuge the supernatant at 12000 rpm for 30 min and collect the precipitate. Wash the precipitate with deionized water twice. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry at -50 °C for 48 h to obtain exfoliated graphene oxide nanosheets.

[0045] 2. Take 1.0 g of exfoliated graphene oxide nanosheets and disperse them in 100 mL of anhydrous ethanol / deionized water mixed solvent (volume ratio 9:1). Disperse the solution by ultrasonication at 300 W for 30 min (3 s working / 3 s intermittent) to obtain a dispersion. Add 0.5 g of KH550 (3-aminopropyltriethoxysilane) to the dispersion and adjust the pH to 4.5 with acetic acid. Stir the solution at 500 rpm for 12 h at 60 °C under nitrogen protection. After the reaction is complete, centrifuge at 10000 rpm for 10 min and collect the precipitate. Wash the precipitate with anhydrous ethanol and centrifuge at 10000 rpm for 10 min. Repeat the washing 3 times. Dry the washed precipitate in a vacuum drying oven at 60 °C for 12 h to obtain aminated graphene oxide.

[0046] 3. Take 0.8 g of aminated graphene oxide, add it to 50 mL of deionized water, and sonicate it at 300 W for 20 min (3 s working / 3 s intermittent) to obtain a carrier dispersion; weigh 2.0 mmol (0.34 g) of 1-naphthoic acid, dissolve it in 20 mL of anhydrous ethanol, add 2.2 mmol EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and 2.2 mmol NHS (N-hydroxysuccinimide), stir and activate at room temperature for 30 min, add it to the carrier dispersion, and react at 400 rpm for 5 h under nitrogen atmosphere and 25 °C to obtain an anchoring group modified carrier dispersion; weigh 0.8 mmol (0.8 g) of polyethylene glycol dicarboxylic acid (Mw=1000), dissolve it in 20 mL of anhydrous ethanol, add 2.08 mmol EDC·HCl and 2.08 mmol NHS was activated by stirring at room temperature for 30 min, then added to the dispersion of the anchoring group modified carrier. The mixture was stirred at 400 rpm for 20 h at 25 °C under a nitrogen atmosphere. After the reaction was completed, the reaction solution was centrifuged at 10,000 rpm for 10 min, and the precipitate was collected and washed with anhydrous ethanol, repeating the washing process 3 times. The precipitate was then washed with deionized water, repeating the washing process 3 times. The washed precipitate was transferred to a freeze-drying bottle and freeze-dried at -50 °C for 48 h to obtain a dispersant for water-based nano-color paste.

[0047] Example 5: A method for preparing a dispersant for aqueous nano-color pastes, comprising the following steps:

[0048] 1. Add 5.0 g of graphene oxide to 500 mL of deionized water and stir magnetically at 500 rpm for 6 h to allow the montmorillonite to fully swell. Transfer to a beaker and sonicate using an ultrasonic cell disruptor at 600 W for 1.5 h (3 s working / 3 s resting), keeping the beaker in an ice-water bath to maintain a temperature below 40 °C. After sonication, centrifuge the dispersion at 3000 rpm for 10 min and collect the supernatant. Centrifuge the supernatant at 12000 rpm for 30 min and collect the precipitate. Wash the precipitate with deionized water twice. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry at -50 °C for 48 h to obtain exfoliated graphene oxide nanosheets.

[0049] 2. Take 1.0 g of exfoliated graphene oxide nanosheets and disperse them in 100 mL of anhydrous ethanol / deionized water mixed solvent (volume ratio 9:1). Disperse the solution by ultrasonication at 300 W for 30 min (3 s working / 3 s intermittent) to obtain a dispersion. Add 0.5 g of KH550 (3-aminopropyltriethoxysilane) to the dispersion and adjust the pH to 4.5 with acetic acid. Stir the solution at 500 rpm for 12 h at 60 °C under nitrogen protection. After the reaction is complete, centrifuge at 10000 rpm for 10 min and collect the precipitate. Wash the precipitate with anhydrous ethanol and centrifuge at 10000 rpm for 10 min. Repeat the washing 3 times. Dry the washed precipitate in a vacuum drying oven at 60 °C for 12 h to obtain aminated graphene oxide.

[0050] 3. Take 0.8 g of aminated graphene oxide, add it to 50 mL of deionized water, and sonicate it at 300 W for 20 min (3 s working / 3 s intermittent) to obtain a carrier dispersion; weigh 2.0 mmol (0.34 g) of 2-naphthoic acid, dissolve it in 20 mL of anhydrous ethanol, add 2.2 mmol EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and 2.2 mmol NHS (N-hydroxysuccinimide), stir and activate at room temperature for 30 min, add it to the carrier dispersion, and react under nitrogen atmosphere at 25 °C with stirring at 400 rpm for 5 h to obtain an anchoring group modified carrier dispersion; weigh 0.8 mmol (0.8 g) of polyglycerol monomethyl ether carboxylic acid (Mw=1000), dissolve it in 20 mL of anhydrous ethanol, add 1.0 mmol EDC·HCl and 1.0 mmol NHS was activated by stirring at room temperature for 30 min, then added to the dispersion of the anchoring group modified carrier. The mixture was stirred at 400 rpm for 20 h at 25 °C under a nitrogen atmosphere. After the reaction was completed, the reaction solution was centrifuged at 10,000 rpm for 10 min, and the precipitate was collected and washed with anhydrous ethanol, repeating the washing process 3 times. The precipitate was then washed with deionized water, repeating the washing process 3 times. The washed precipitate was transferred to a freeze-drying bottle and freeze-dried at -50 °C for 48 h to obtain a dispersant for water-based nano-color paste.

[0051] Example 6 A method for preparing a dispersant for aqueous nano-color paste, comprising the following steps:

[0052] 1. Add 5.0 g of graphene oxide to 500 mL of deionized water and stir magnetically at 500 rpm for 6 h to allow the montmorillonite to fully swell. Transfer to a beaker and sonicate using an ultrasonic cell disruptor at 600 W for 1.5 h (3 s working / 3 s resting), keeping the beaker in an ice-water bath to maintain a temperature below 40 °C. After sonication, centrifuge the dispersion at 3000 rpm for 10 min and collect the supernatant. Centrifuge the supernatant at 12000 rpm for 30 min and collect the precipitate. Wash the precipitate with deionized water twice. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry at -50 °C for 48 h to obtain exfoliated graphene oxide nanosheets.

[0053] 2. Take 1.0 g of exfoliated graphene oxide nanosheets and disperse them in 100 mL of anhydrous ethanol / deionized water mixed solvent (volume ratio 9:1). Disperse the solution by ultrasonication at 300 W for 30 min (3 s working / 3 s intermittent) to obtain a dispersion. Add 0.5 g of KH550 (3-aminopropyltriethoxysilane) to the dispersion and adjust the pH to 4.5 with acetic acid. Stir the solution at 500 rpm for 12 h at 60 °C under nitrogen protection. After the reaction is complete, centrifuge at 10000 rpm for 10 min and collect the precipitate. Wash the precipitate with anhydrous ethanol and centrifuge at 10000 rpm for 10 min. Repeat the washing 3 times. Dry the washed precipitate in a vacuum drying oven at 60 °C for 12 h to obtain aminated graphene oxide.

[0054] 3. Take 0.8 g of aminated graphene oxide, add it to 50 mL of deionized water, and sonicate it at 300 W for 20 min (3 s working / 3 s intermittent) to obtain a carrier dispersion; weigh 2.0 mmol (0.40 g) of biphenyl-4-carboxylic acid, dissolve it in 20 mL of anhydrous ethanol, add 2.2 mmol EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and 2.2 mmol NHS (N-hydroxysuccinimide), stir and activate at room temperature for 30 min, add it to the carrier dispersion, and react under nitrogen atmosphere at 25 °C with stirring at 400 rpm for 5 h to obtain an anchoring group modified carrier dispersion; weigh 0.8 mmol (0.8 g) of polyglycerol monomethyl ether carboxylic acid (Mw=1000), dissolve it in 20 mL of anhydrous ethanol, add 1.0 mmol EDC·HCl and 1.0 mmol NHS was activated by stirring at room temperature for 30 min, then added to the dispersion of the anchoring group modified carrier. The mixture was stirred at 400 rpm for 20 h at 25 °C under a nitrogen atmosphere. After the reaction was completed, the reaction solution was centrifuged at 10,000 rpm for 10 min, and the precipitate was collected and washed with anhydrous ethanol, repeating the washing process 3 times. The precipitate was then washed with deionized water, repeating the washing process 3 times. The washed precipitate was transferred to a freeze-drying bottle and freeze-dried at -50 °C for 48 h to obtain a dispersant for water-based nano-color paste.

[0055] Comparative Example 1: A method for preparing a dispersant for aqueous nano-color pastes, differing from Example 1 in that it does not graft anchoring groups, and includes the following steps:

[0056] 1. Add 5.0 g of sodium montmorillonite to 500 mL of deionized water and stir magnetically at 500 rpm for 12 h to allow the montmorillonite to fully swell. Transfer to a beaker and sonicate using an ultrasonic cell disruptor at 600 W for 2 h (3 s working / 3 s resting), keeping the beaker in an ice-water bath at ≤40℃ during this period. After sonication, centrifuge the dispersion at 3000 rpm for 10 min and collect the supernatant. Centrifuge the supernatant at 12000 rpm for 30 min and collect the precipitate. Wash the precipitate with deionized water twice. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry at -50℃ for 48 h to obtain exfoliated montmorillonite nanosheets.

[0057] 2. Take 1.0 g of exfoliated montmorillonite nanosheets and disperse them in 100 mL of anhydrous ethanol / deionized water mixed solvent (volume ratio 9:1). Disperse the nanosheets using ultrasonication at 300 W for 30 min (3 s working / 3 s intermittent) to obtain a dispersion. Add 0.5 g of KH550 (3-aminopropyltriethoxysilane) to the dispersion, adjust the pH to 4.5 using acetic acid, and react at 500 rpm for 12 h under nitrogen protection at 60 °C. After the reaction, centrifuge at 10000 rpm for 10 min and collect the precipitate. Wash the precipitate with anhydrous ethanol, centrifuge at 10000 rpm for 10 min, and repeat the washing three times. Dry the washed precipitate in a vacuum drying oven at 60 °C for 12 h to obtain aminated montmorillonite.

[0058] 3. Take 0.8 g of aminated montmorillonite and add it to 50 mL of deionized water. Disperse it by ultrasonication at 300 W for 20 min (3 s working / 3 s intermittent) to obtain a carrier dispersion. Weigh 1.0 mmol (0.75 g) of polyethylene glycol monomethyl ether carboxylic acid (Mw=750), dissolve it in 20 mL of anhydrous ethanol, add 1.3 mmol EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and 1.3 mmol NHS (N-hydroxysuccinimide), stir and activate at room temperature for 30 min, add it to the carrier dispersion, and react at 400 rpm for 20 h under nitrogen atmosphere and 25 °C. After the reaction, centrifuge the reaction solution at 10000 rpm for 10 min, collect the precipitate and wash it with anhydrous ethanol. Repeat the washing 3 times. Then wash it with deionized water. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry it at -50 °C for 48 h to obtain a dispersant for water-based nano-color paste.

[0059] Comparative Example 2: A method for preparing a dispersant for aqueous nano-color pastes, differing from Example 1 in that it does not graft solvation chains, and includes the following steps:

[0060] 1. Add 5.0 g of sodium montmorillonite to 500 mL of deionized water and stir magnetically at 500 rpm for 12 h to allow the montmorillonite to fully swell. Transfer to a beaker and sonicate using an ultrasonic cell disruptor at 600 W for 2 h (3 s working / 3 s resting), keeping the beaker in an ice-water bath at ≤40℃ during this period. After sonication, centrifuge the dispersion at 3000 rpm for 10 min and collect the supernatant. Centrifuge the supernatant at 12000 rpm for 30 min and collect the precipitate. Wash the precipitate with deionized water twice. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry at -50℃ for 48 h to obtain exfoliated montmorillonite nanosheets.

[0061] 2. Take 1.0 g of exfoliated montmorillonite nanosheets and disperse them in 100 mL of anhydrous ethanol / deionized water mixed solvent (volume ratio 9:1). Disperse the nanosheets using ultrasonication at 300 W for 30 min (3 s working / 3 s intermittent) to obtain a dispersion. Add 0.5 g of KH550 (3-aminopropyltriethoxysilane) to the dispersion, adjust the pH to 4.5 using acetic acid, and react at 500 rpm for 12 h under nitrogen protection at 60 °C. After the reaction, centrifuge at 10000 rpm for 10 min and collect the precipitate. Wash the precipitate with anhydrous ethanol, centrifuge at 10000 rpm for 10 min, and repeat the washing three times. Dry the washed precipitate in a vacuum drying oven at 60 °C for 12 h to obtain aminated montmorillonite.

[0062] 3. Take 0.8 g of aminated montmorillonite and add it to 50 mL of deionized water. Disperse it by ultrasonication at 300 W for 20 min (3 s working / 3 s intermittent) to obtain a carrier dispersion. Weigh 1.0 mmol (0.28 g) of 1-pyrene butyric acid and dissolve it in 20 mL of anhydrous ethanol. Add 1.1 mmol EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and 1.1 mmol NHS (N-hydroxysuccinimide). Stir and activate at room temperature for 30 min. Add the activated ethanol to the carrier dispersion and react at 400 rpm for 20 h under nitrogen atmosphere and at 25 °C. After the reaction is complete, centrifuge the reaction solution at 10000 rpm for 10 min. Collect the precipitate and wash it with anhydrous ethanol. Repeat the washing 3 times. Then wash it with deionized water. Repeat the washing 3 times. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry it at -50 °C for 48 h to obtain a dispersant for water-based nano-color paste.

[0063] Comparative Example 3: A method for preparing a dispersant for an aqueous nano-color paste, differing from Example 1 in that the anchoring group reagent and the solvation chain reagent are physically mixed with the exfoliated montmorillonite nanosheets, including the following steps:

[0064] 1. Add 5.0 g of sodium montmorillonite to 500 mL of deionized water and stir magnetically at 500 rpm for 12 h to allow the montmorillonite to fully swell. Transfer to a beaker and sonicate using an ultrasonic cell disruptor at 600 W for 2 h (3 s working / 3 s resting), keeping the beaker in an ice-water bath at ≤40℃ during this period. After sonication, centrifuge the dispersion at 3000 rpm for 10 min and collect the supernatant. Centrifuge the supernatant at 12000 rpm for 30 min and collect the precipitate. Wash the precipitate with deionized water twice. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry at -50℃ for 48 h to obtain exfoliated montmorillonite nanosheets.

[0065] 2. Take 1.0 g of exfoliated montmorillonite nanosheets and disperse them in 100 mL of anhydrous ethanol / deionized water mixed solvent (volume ratio 9:1). Disperse the nanosheets using ultrasonication at 300 W for 30 min (3 s working / 3 s intermittent) to obtain a dispersion. Add 0.5 g of KH550 (3-aminopropyltriethoxysilane) to the dispersion, adjust the pH to 4.5 using acetic acid, and react at 500 rpm for 12 h under nitrogen protection at 60 °C. After the reaction, centrifuge at 10000 rpm for 10 min and collect the precipitate. Wash the precipitate with anhydrous ethanol, centrifuge at 10000 rpm for 10 min, and repeat the washing three times. Dry the washed precipitate in a vacuum drying oven at 60 °C for 12 h to obtain aminated montmorillonite.

[0066] 3. Take 0.8g of aminated montmorillonite and add it to 50mL of deionized water. Disperse it by ultrasonication at 300W for 20min (3s working / 3s intermittent) to obtain a carrier dispersion. Weigh 1.0mmol (0.28g) of 1-pyrenebutyric acid and 1.0mmol (0.75g) of polyethylene glycol monomethyl ether carboxylic acid (Mw=750), dissolve them in 40mL of anhydrous ethanol, and stir until completely dissolved to obtain a mixed solution. Add the mixed solution directly to the carrier dispersion and stir at 400 rpm for 5h under a nitrogen atmosphere at 25℃. After the reaction is complete, centrifuge the reaction solution at 10000rpm for 10min, collect the precipitate, wash it with anhydrous ethanol, and repeat the washing 3 times. Then wash it with deionized water and repeat the washing 3 times. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry it at -50℃ for 48h to obtain a dispersant for water-based nano-color paste.

[0067] Comparative Example 4: A method for preparing an aqueous nano-color paste dispersant, differing from Example 1 in that an anchoring group reagent and a solvation chain reagent are added simultaneously during preparation, including the following steps:

[0068] 1. Add 5.0 g of sodium montmorillonite to 500 mL of deionized water and stir magnetically at 500 rpm for 12 h to allow the montmorillonite to fully swell. Transfer to a beaker and sonicate using an ultrasonic cell disruptor at 600 W for 2 h (3 s working / 3 s resting), keeping the beaker in an ice-water bath at ≤40℃ during this period. After sonication, centrifuge the dispersion at 3000 rpm for 10 min and collect the supernatant. Centrifuge the supernatant at 12000 rpm for 30 min and collect the precipitate. Wash the precipitate with deionized water twice. Transfer the washed precipitate to a freeze-drying bottle and freeze-dry at -50℃ for 48 h to obtain exfoliated montmorillonite nanosheets.

[0069] 2. Take 1.0 g of exfoliated montmorillonite nanosheets and disperse them in 100 mL of anhydrous ethanol / deionized water mixed solvent (volume ratio 9:1). Disperse the nanosheets using ultrasonication at 300 W for 30 min (3 s working / 3 s intermittent) to obtain a dispersion. Add 0.5 g of KH550 (3-aminopropyltriethoxysilane) to the dispersion, adjust the pH to 4.5 using acetic acid, and react at 500 rpm for 12 h under nitrogen protection at 60 °C. After the reaction, centrifuge at 10000 rpm for 10 min and collect the precipitate. Wash the precipitate with anhydrous ethanol, centrifuge at 10000 rpm for 10 min, and repeat the washing three times. Dry the washed precipitate in a vacuum drying oven at 60 °C for 12 h to obtain aminated montmorillonite.

[0070] 3. Take 0.8 g of aminated montmorillonite and add it to 50 mL of deionized water. Disperse the mixture using ultrasonication at 300 W for 20 min (3 s working / 3 s intermittent) to obtain the carrier dispersion. Weigh 1.0 mmol (0.28 g) of 1-pyrenebutyric acid and 1.0 mmol (0.75 g) of polyethylene glycol monomethyl ether carboxylic acid (Mw=750), dissolve them in 40 mL of anhydrous ethanol, and add 2.4 mmol of EDC·HCl (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and 2.4 mmol of NHS (N-hydroxysuccinate). Imide was activated by stirring at room temperature for 30 min, added to the carrier dispersion, and reacted at 400 rpm for 5 h under nitrogen atmosphere and 25 °C to obtain a modified carrier dispersion. The reaction was then carried out under nitrogen atmosphere and 25 °C with stirring at 400 rpm for 24 h. After the reaction was completed, the reaction solution was centrifuged at 10000 rpm for 10 min, the precipitate was collected and washed with anhydrous ethanol, and the washing was repeated 3 times. Then it was washed with deionized water, and the washing was repeated 3 times. The washed precipitate was transferred to a lyophilization bottle and freeze-dried at -50 °C for 48 h to obtain a dispersant for water-based nano-color paste.

[0071] Comparative Example 5: A method for preparing a dispersant for an aqueous nano-color paste, which differs from Example 1 in that an ionic dispersant, styrene-maleic anhydride copolymer ammonium salt, is used as the dispersant.

[0072] Performance testing

[0073] The dispersant used in Examples 1-6 and Comparative Examples 1-5 was used to prepare the aqueous nano-color paste. The steps were as follows: the dispersant was added to deionized water and stirred until completely dissolved. The defoamer and bactericide were added and stirred evenly. The pigment was added and dispersed at 1000 rpm for 15 min using a high-speed disperser. The mixture was then transferred to a sand mill, and 0.3-0.5 mm zirconia beads were added. The mixture was ground at 2500 rpm for 4 h and filtered to obtain the aqueous nano-color paste.

[0074] The above component distribution is shown in Table 1:

[0075] Table 1 Formulation for the preparation of water-based nano-color pastes

[0076]

[0077] The prepared aqueous nano-color paste was subjected to the following performance tests:

[0078] 1. Viscosity Measurement

[0079] Viscosity was measured using the dispersants prepared in Examples 1-6 and Comparative Examples 1-5: 20 mL of the aqueous nano-color paste was placed in a sample cup, and a rotational viscometer was used with an SC4-18 rotor, setting the shear rate to 100 s. -1 The sample was kept at 25℃ for 5 minutes, and the viscosity value was read. Each sample was tested 3 times and the average value was taken.

[0080] Take another 20 mL of water-based nano pigment and place it in a 50℃ oven. After 30 and 60 days, measure the viscosity using the same method and read the viscosity value. Test each sample 3 times and take the average value.

[0081] The experimental results are shown in Table 2:

[0082] Table 2. Results of viscosity measurement experiment

[0083]

[0084] As can be seen from Table 2, the aqueous nano-color pastes prepared by the dispersants in Examples 1 to 6 all exhibited relatively low viscosity under initial conditions, and the viscosity increase was relatively small after the accelerated test at 50°C. This indicates that the present invention can effectively reduce the viscosity of the color paste and impart excellent long-term storage stability to the system.

[0085] The high initial viscosity of Comparative Examples 1 and 2, along with their high 60-day viscosity growth rate, indicates that the absence of anchoring groups and solvation chains prevents the dispersant from effectively adsorbing onto the pigment surface or providing sufficient steric hindrance, leading to pigment particle aggregation and increased viscosity. The results of Comparative Example 3 demonstrate that physical mixing alone cannot stably fix functional molecules onto the nanosheet surface, resulting in poor dispersion. The results of Comparative Example 4 highlight the superiority of the distribution grafting strategy of this invention in ensuring that anchoring groups preferentially occupy active sites. The viscosity index and long-term stability of Comparative Example 5 are inferior to those of the embodiments of this invention, further demonstrating the significant advantages of the technical solution of this invention in terms of dispersion performance and storage stability.

[0086] 2. Average particle size determination

[0087] Take 0.1g of water-based nano pigment, dilute it 1000 times with deionized water, ultrasonically disperse it for 1 min, transfer it to a cuvette, let it stand at 25℃ for 2 min, perform DLS test, and record the D50 average particle size and polydispersity index (PDI). Each sample is tested 3 times and the average value is taken.

[0088] Separately, water-based nano-pigment pastes were placed in a 50℃ oven for 30 and 60 days. The average particle size was then determined using the same method, and the D50 average particle size and polydispersity index (PDI) were recorded. Each sample was tested three times, and the average value was taken. The experimental results are shown in Table 3.

[0089] Table 3. Results of average particle size determination experiment

[0090]

[0091] As can be seen from Table 3, the aqueous nano-pigments prepared in Examples 1 to 6 of this invention all exhibited small average particle size in the initial state. After being stored at 50°C for 60 days, the increase in particle size was also small. This indicates that the technical solution of using inorganic two-dimensional nanosheets as rigid carriers and covalently linking anchoring groups and hydrophilic solvation chains to the carrier surface through a stepwise grafting strategy can achieve nanoscale dispersion of pigment particles and endow the system with excellent anti-agglomeration ability.

[0092] Comparative Examples 1 and 2 both had high initial particle sizes and significant growth rates after 60 days of storage, indicating that the absence of anchoring groups and solvation chains prevents the dispersant from effectively adsorbing onto the pigment surface or providing sufficient steric hindrance, causing pigment particles to continuously aggregate during storage. The results of Comparative Example 3 show that physical mixing alone cannot stably fix functional molecules onto the nanosheet surface; anchoring groups and solvation chains are easily detached and cannot exert a synergistic dispersing effect. Comparative Example 4 simultaneously performed grafting reactions of anchoring groups and solvation chains, verifying that the stepwise grafting strategy of this scheme ensures that anchoring groups preferentially occupy active sites and avoids interference from the steric hindrance of large molecular solvation chains. The results of Comparative Example 5 show that the particle size and long-term stability are inferior to those of the embodiments of the present invention, indicating that the dispersant prepared by the present invention is superior to commercially available products in achieving nanoscale dispersion and maintaining long-term particle size stability.

[0093] 3. Centrifugal stability test

[0094] Take 10 mL of water-based nano pigment and place it in a 15 mL centrifuge tube. Centrifuge at 3000 rpm for 30 min. After centrifugation, observe the precipitation and determine the amount of precipitation. The precipitation amount is rated from least to most as follows: no precipitation (no visible precipitation at the bottom of the tube after centrifugation, and the pigment is uniform), trace precipitation (a very thin layer of precipitation at the bottom of the tube, which can flow when tilted), small amount of precipitation (a clear precipitation layer at the bottom of the tube, which is not easy to flow when tilted), and large amount of precipitation (thick precipitation at the bottom of the tube, and the supernatant is clear or turbid).

[0095] Another water-based nano-color paste was placed in a 50℃ oven and left for 30 and 60 days. The sedimentation amount was then determined by centrifugation using the same method.

[0096] The experimental results are shown in Table 4:

[0097] Table 4 Centrifugation stability test results

[0098]

[0099] As can be seen from Table 4, the aqueous nano-slurries prepared using the dispersants of Examples 1 to 6 showed no precipitation or at least a small amount of precipitation after centrifugation at 3000 rpm for 30 min. Among them, the sample of Example 4 performed the best. This indicates that the dispersant prepared by the present invention can stably disperse pigment particles in the aqueous phase and has excellent anti-settling ability.

[0100] After accelerated storage at 50°C for 30 and 60 days, the centrifugal stability of Examples 1-6 remained good, while Comparative Examples 1-5 showed small to large amounts of precipitation. Comparative Examples 1 and 2 showed large amounts of precipitation at all points, indicating that the lack of anchoring groups and solvation chains prevented stable dispersion of the aqueous nano-pigment. The absence of anchoring groups prevented the dispersant from effectively adsorbing onto the pigment surface, and the absence of solvation chains resulted in insufficient steric hindrance. Comparative Example 3 showed weaker stability than all other examples, indicating that only by linking both anchoring groups and solvation chains to the two-dimensional nanosheet could its optimal dispersion performance be achieved. Comparative Example 4 simultaneously linked anchoring groups and solvation chains to the two-dimensional nanosheet; due to the competition between the anchoring groups and solvation chains... The active sites on the surface of aminated montmorillonite and the steric hindrance of the macromolecular solvation chains hinder the full grafting of small molecule anchoring groups, resulting in insufficient anchoring density and affecting dispersion performance. Comparative Example 5 used a commercially available ionic dispersant, which showed good dispersion performance on day 0, but as the storage time increased, a small amount of precipitation appeared on day 30 and a large amount of precipitation appeared on day 60. This indicates that ionic dispersants rely on electrostatic adsorption for dispersion, and during storage, they are subject to desorption due to factors such as pH changes and ionic strength, resulting in the re-aggregation of pigment particles. In contrast, the dispersant of this invention fixes the anchoring groups on the two-dimensional nanosheet carrier through covalent bonds, and its binding with the pigment does not rely on electrostatic adsorption, thus exhibiting superior long-term storage stability.

[0101] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a dispersant for aqueous nano-color pastes, characterized in that, Includes the following steps: S1. Aminated inorganic two-dimensional nanosheets are added to deionized water and ultrasonically dispersed to obtain a carrier dispersion. S2. Dissolve the anchoring group reagent in anhydrous ethanol, add EDC·HCl and NHS, activate at room temperature for 20~40 min, add to the carrier dispersion, and react at 20~25℃ in a nitrogen atmosphere for 4~6 h to obtain the anchoring group modified carrier dispersion. S3. Dissolve the solvation chain reagent in anhydrous ethanol, add EDC·HCl and NHS, activate at room temperature for 20~40 min, add to the anchoring group modified carrier dispersion, and react at 20~25℃ under nitrogen atmosphere for 12~24 h. S4. After the reaction is complete, centrifuge and collect the precipitate. Wash the precipitate with anhydrous ethanol and deionized water in sequence, freeze dry, and obtain a water-based nano-color paste dispersant.

2. The method for preparing an aqueous nano-color paste dispersant according to claim 1, characterized in that, In step S1, the preparation method of aminated inorganic two-dimensional nanosheets is as follows: the exfoliated two-dimensional nanosheets are dispersed in an ethanol solution and sonicated to obtain a dispersion; an aminosilane coupling agent is added, the pH is adjusted to 4.5~5.0, and the mixture is stirred and reacted at 50~65℃ under a nitrogen atmosphere for 10~16h. After centrifugation, the precipitate is collected, washed, and dried to obtain aminated inorganic two-dimensional nanosheets.

3. The method for preparing an aqueous nano-color paste dispersant according to claim 2, characterized in that, The method for preparing the exfoliated two-dimensional nanosheets is as follows: montmorillonite or graphene oxide is added to deionized water, stirred for 6-12 hours, sonicated at 500-700W for 1.5-4 hours while maintaining the temperature below 40℃, centrifuged at 2000-4000rpm for 10-20 minutes, the supernatant is collected, centrifuged at 10000-14000rpm for 20-40 minutes, the precipitate is collected, washed, and freeze-dried to obtain the exfoliated two-dimensional nanosheets.

4. The method for preparing an aqueous nano-color paste dispersant according to claim 1, characterized in that, In step S2, the anchoring group reagent is any one of 1-pyrenepropionic acid, 1-pyrenebutyric acid, 9-anthracarboxylic acid, 1-naphthoic acid, 2-naphthoic acid, or biphenyl-4-carboxylic acid.

5. The method for preparing an aqueous nano-color paste dispersant according to claim 1, characterized in that, In step S3, the solvation chain reagent is any one of polyethylene glycol monomethyl ether carboxylic acid, polypropylene glycol monomethyl ether carboxylic acid, polyethylene glycol-polypropylene glycol block copolymer monomethyl ether carboxylic acid, polyethylene glycol dicarboxylic acid, or polyglycerol monomethyl ether carboxylic acid.

6. The method for preparing an aqueous nano-color paste dispersant according to claim 1, characterized in that, In step S2, the molar ratio of the carboxylic acid group in the anchoring group reagent to EDC·HCl and NHS is 1:1~1.2:1~1.2; in step S3, the molar ratio of the carboxylic acid group in the solvation chain reagent to EDC·HCl and NHS is 1:1~1.5:1~1.

5.

7. The method for preparing an aqueous nano-color paste dispersant according to claim 1, characterized in that, The mass ratio of the aminated inorganic two-dimensional nanosheets, the anchoring group reagent, and the solvated chain reagent is 1:0.2~0.8:0.5~1.

8. The method for preparing an aqueous nano-color paste dispersant according to claim 3, characterized in that, The montmorillonite is one of sodium-based montmorillonite, calcium-based montmorillonite, or magnesium-based montmorillonite.

9. A dispersant for aqueous nano-color pastes, characterized in that, The dispersant for the aqueous nano-color paste is prepared by any one of claims 1 to 8.

Images