A wetting dispersant and a method for its preparation

Abstract

This invention relates to the field of wetting and dispersing agents, and discloses a wetting and dispersing agent and its preparation method. The invention involves polymerizing benzidine disulfonic acid, 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid, and glutaraldehyde, followed by reduction with sodium borohydride to obtain a wetting and dispersing agent. This agent contains a large amount of sulfonates, carboxylates, and imino groups, which can act as anchoring groups for pigments, interacting with them and providing better dispersion. Combined with dispersant 6600, it effectively achieves wetting and dispersion effects for red, black, and other pigments. The resulting pigment paste has low viscosity and good viscosity reduction effect, which is beneficial for improving the processing fluidity and storage stability of the pigment paste, improving grinding effect, enhancing pigment tinting strength and paint film brightness, and improving the floating color performance of the tinting system.

Description

Technical Field

[0001] This invention relates to the field of wetting and dispersing agents, specifically to a wetting and dispersing agent and its preparation method. Background Technology

[0002] In the grinding process of water-based paint pigment pastes, in order to improve the dispersion effect of pigments, it is usually necessary to add dispersants for grinding, dispersing and stabilizing pigments. Since some pigments have poor hydrophilicity, adding only the main dispersant for grinding may result in insufficient wetting ability. In this case, it is necessary to add some auxiliary dispersants, surfactants and other additives to work in conjunction with the main dispersant, which will solve this problem well. These additives mainly provide the function of wetting the pigment surface and further improve the dispersion effect.

[0003] Introducing anchoring groups such as sulfonates, carboxylates, and amino groups into wetting and dispersing agents can enhance their interaction with pigments, effectively achieving pigment dispersion. Patent CN114031717B discloses polycarboxylates with high sulfonic acid content, their preparation method, and their application in dispersant preparation. Using styrene, maleic anhydride, allyl carboxylic acid, aminobenzenesulfonic acid, and hydroxyalkyl sulfonic acid monomers as raw materials, the prepared polycarboxylates exhibit good dye dispersion effects. However, the dispersant in this patent does not reduce the viscosity of the color paste, which is detrimental to the processing fluidity and storage stability of the color paste. Summary of the Invention

[0004] Technical problem to be solved: In view of the shortcomings of the prior art, the present invention provides a wetting and dispersing agent with high dispersibility.

[0005] The technical solution of this invention: A method for preparing a wetting and dispersing agent: (1) Add 1,7-bis-Boc-1,4,7-triazaheptane and succinic anhydride to dichloromethane, stir at 20-30℃ for 12-18 h, distill under reduced pressure, add the product to ethyl acetate, wash with 5% citric acid aqueous solution, dry the organic phase with anhydrous magnesium sulfate, filter, distill under reduced pressure, add the product to a dichloromethane solution of trifluoroacetic acid, stir at 20-30℃ for 2-3 h, distill under reduced pressure, add dichloromethane, wash with saturated sodium bicarbonate solution, dry the organic phase with anhydrous magnesium sulfate, filter, distill under reduced pressure, recrystallize the product in diethyl ether to obtain 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid, the reaction formula is: .

[0006] (2) Add benzidine disulfonic acid, 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid and glutaraldehyde aqueous solution to dimethyl sulfoxide, stir the reaction, add ethanol to the solution, filter, wash the product with ethanol, dry, and obtain the dispersant precursor.

[0007] (3) Add the dispersant precursor and sodium borohydride to ethanol, stir to react, add water to dilute, add sodium hydroxide, stir and heat to evaporate, precipitate out, cool in an ice-water bath, filter, wash with ethanol, dry, and obtain the wetting and dispersing agent. The reaction formula is: .

[0008] Furthermore, in (1), the ratio of 1,7-bis-Boc-1,4,7-triazaheptane to succinic anhydride is 1 mol: (1.4-1.6) mol.

[0009] Furthermore, in (2), the ratio of benzidine disulfonic acid, 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid, and glutaraldehyde is (0.4-0.7) mol: (0.3-0.6) mol: 1 mol.

[0010] Furthermore, in (2), the reaction temperature is 70-85℃ and the reaction time is 18-24h.

[0011] Furthermore, in (3), the ratio of dispersant precursor to sodium borohydride is 100g: (18-24)g.

[0012] Furthermore, in (3), the reaction temperature is 20-30℃ and the reaction time is 5-8h.

[0013] Furthermore, sodium hydroxide is added to (3) to adjust the pH of the solution to 8-9.

[0014] The beneficial technical effects of this invention are as follows: This invention involves polymerizing benzidine disulfonic acid, 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid, and glutaraldehyde, followed by reduction with sodium borohydride, to obtain a wetting and dispersing agent. This agent contains a large amount of sulfonates, carboxylates, and imino groups, which can act as anchoring groups for pigments and interact with them, resulting in better pigment dispersion. When combined with dispersant 6600, it can effectively achieve wetting and dispersion effects for red, black, and other pigments. The resulting pigment paste has low viscosity and good viscosity reduction effect, which is beneficial for improving the processing fluidity and storage stability of the pigment paste, improving the grinding effect, enhancing the pigment's color development power and paint film brightness, and improving the floating color performance of the color mixing system. Attached Figure Description

[0015] Figure 1 It's a picture of resin-free red paste paint.

[0016] Figure 2 It's a picture of resin-free black paste baking paint.

[0017] Figure 3 It is a picture of resin-free brown paste paint. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. 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.

[0019] Example 1 (1) Add 30 mmol of 1,7-bis-Boc-1,4,7-triazaheptane and 42 mmol of succinic anhydride to 150 mL of dichloromethane, stir at 30 °C for 12 h, distill under reduced pressure, add the product to ethyl acetate, wash with 5% citric acid aqueous solution, dry the organic phase with anhydrous magnesium sulfate, filter, distill under reduced pressure, add the product to 90 mL of 30% trifluoroacetic acid in dichloromethane, stir at 30 °C for 2 h, distill under reduced pressure, add dichloromethane, wash with saturated sodium bicarbonate solution, dry the organic phase with anhydrous magnesium sulfate, filter, distill under reduced pressure, recrystallize the product in diethyl ether to obtain 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid.

[0020] (2) Add 40 mmol benzidine disulfonic acid, 60 mmol 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid, and 20 mL of aqueous solution containing 100 mmol glutaraldehyde to 600 mL of dimethyl sulfoxide. Heat to 75 °C and stir for 24 h. Add ethanol to the solution, filter, wash the product with ethanol, and dry to obtain the dispersant precursor.

[0021] (3) Add 20g of dispersant precursor and 4g of sodium borohydride to 500mL of ethanol, stir and react at 20℃ for 6h, add 200mL of water to dilute, add sodium hydroxide to adjust the pH of the solution to 8, stir and heat to evaporate, precipitate out, cool in ice water bath, filter, wash with ethanol, dry, and obtain wetting dispersant.

[0022] Example 2 (1) Add 30 mmol of 1,7-bis-Boc-1,4,7-triazaheptane and 48 mmol of succinic anhydride to 150 mL of dichloromethane, stir at 20 °C for 18 h, distill under reduced pressure, add the product to ethyl acetate, wash with 5% citric acid aqueous solution, dry the organic phase with anhydrous magnesium sulfate, filter, distill under reduced pressure, add the product to 90 mL of 30% trifluoroacetic acid in dichloromethane, stir at 20 °C for 3 h, distill under reduced pressure, add dichloromethane, wash with saturated sodium bicarbonate solution, dry the organic phase with anhydrous magnesium sulfate, filter, distill under reduced pressure, recrystallize the product in diethyl ether to obtain 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid.

[0023] (2) Add 55 mmol benzidine disulfonic acid, 45 mmol 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid, and 20 mL of aqueous solution containing 100 mmol glutaraldehyde to 600 mL of dimethyl sulfoxide. Heat to 70 °C and stir for 24 h. Add ethanol to the solution, filter, wash the product with ethanol, and dry to obtain the dispersant precursor.

[0024] (3) Add 20g of dispersant precursor and 4.8g of sodium borohydride to 500mL of ethanol, stir and react at 30℃ for 5h, add 300mL of water to dilute, add sodium hydroxide to adjust the pH of the solution to 9, stir and heat to evaporate, precipitate out, cool in an ice water bath, filter, wash with ethanol, dry, and obtain wetting dispersant.

[0025] Example 3 (1) Add 70 mmol benzidine disulfonic acid, 30 mmol 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid (prepared from Example 1) and 20 mL of aqueous solution containing 100 mmol glutaraldehyde to 700 mL of dimethyl sulfoxide. Heat to 85 °C and stir for 18 h. Add ethanol to the solution, filter, wash the product with ethanol, and dry to obtain the dispersant precursor.

[0026] (2) Add 20g of dispersant precursor and 3.6g of sodium borohydride to 400mL of ethanol, stir and react at 20℃ for 8h, add 200mL of water to dilute, add sodium hydroxide to adjust the pH of the solution to 9, stir and heat to evaporate, precipitate out, cool in an ice water bath, filter, wash with ethanol, dry, and obtain wetting dispersant.

[0027] Comparative Example 1 uses a dispersant precursor (prepared from Example 1) as a wetting and dispersing agent.

[0028] Comparative Example 2 differs from Example 1 in that 1,5-pentanediamine is used instead of 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid.

[0029] (1) Add 40 mmol benzidine disulfonic acid, 60 mmol 1,5-pentanediamine and 20 mL of aqueous solution containing 100 mmol glutaraldehyde to 600 mL dimethyl sulfoxide, heat to 75 °C, stir and react for 24 h, add ethanol to the solution, filter and wash the product with ethanol, dry to obtain the dispersant precursor.

[0030] (2) Add 20g of dispersant precursor and 4g of sodium borohydride to 500mL of ethanol, stir and react at 20℃ for 6h, add 200mL of water to dilute, add sodium hydroxide to adjust the pH of the solution to 8, stir and heat to evaporate, precipitate out, cool in an ice water bath, filter, wash with ethanol, dry, and obtain wetting dispersant.

[0031] Comparative Example 3 differs from Example 1 in that benzidine diamine is used instead of benzidine disulfonic acid.

[0032] (1) Add 40 mmol of benzidine, 60 mmol of 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid, and 20 mL of an aqueous solution containing 100 mmol of glutaraldehyde to 600 mL of dimethyl sulfoxide. Heat to 75 °C and stir for 24 h. Add ethanol to the solution, filter, wash the product with ethanol, and dry to obtain the dispersant precursor.

[0033] (2) Add 20g of dispersant precursor and 4g of sodium borohydride to 500mL of ethanol, stir and react at 20℃ for 6h, add 200mL of water to dilute, add sodium hydroxide to adjust the pH of the solution to 8, stir and heat to evaporate, precipitate out, cool in an ice water bath, filter, wash with ethanol, dry, and obtain wetting dispersant.

[0034] Comparative Example 4 used commercially available dispersant AFCONA6226 as a wetting and dispersing agent.

[0035] Preparation of resin-free red paste: Add 18g of dispersant Jin Tuan 6090, 1.5g of defoamer Jin Tuan 3300W, and 60g of red pigment (model Hangzhou Baihe F5RK) to 70.5mL of deionized water, stir, grind and disperse to obtain a resin-free red paste blank control.

[0036] Add 15g of dispersant Jin Tuan 6090, 3g of wetting and dispersing agent (prepared from each example and comparative example), 1.5g of defoamer Jin Tuan 3300W, and 60g of red pigment (model Hangzhou Baihe F5RK) to 70.5mL of deionized water, stir, grind and disperse to obtain resin-free red paste.

[0037] The viscosity of the red paste was tested using a rotational viscometer.

[0038] Table 1 Properties of Resin-Free Red Paste

[0039] Preparation of resin-free black paste: Add 30g of dispersant Jin Tuan 6090, 0.75g of defoamer Jin Tuan 3300W, and 37.5g of black pigment (Shanghai Coking Carbon Black C311) to 81.75mL of deionized water, stir, grind and disperse to obtain a resin-free black paste blank control.

[0040] Add 24g of dispersant Jin Tuan 6090, 6g of wetting and dispersing agent (prepared from each example and comparative example), 0.75g of defoamer Jin Tuan 3300W, and 37.5g of black pigment (model Shanghai Coking Carbon Black C311) to 81.75mL of deionized water, stir, grind and disperse to obtain resin-free black paste.

[0041] Table 2 Performance of Resin-Free Black Pulp

[0042] Preparation of resin-free brown paste: Add 40g ethylene glycol butyl ether, 50g dispersant Jin Tuan 6090, and 70g color powder (transparent iron oxide red powder Zhengqi Shirong TR-718) to 40mL of deionized water, stir, grind and disperse to obtain a resin-free brown paste blank control.

[0043] Add 40g of ethylene glycol butyl ether, 40g of dispersant Jin Tuan 6090, 10g of wetting and dispersing agent (prepared from each example and comparative example), and 70g of color powder (transparent iron oxide red powder Zhengqi Shirong TR-718) to 40mL of deionized water, stir, grind and disperse to obtain a resin-free brown paste.

[0044] Table 3 Properties of Resin-Free Brown Paste

[0045] After testing, it was found that using dispersant 6600 as the main dispersant, combined with the wetting and dispersing agents in each embodiment, resulted in a color paste with lower viscosity and better wetting, dispersing, and viscosity-reducing properties.

[0046] Mix 55g of water-soluble acrylic resin (Golden Group 5207N), 8g of amino resin (Cyttrium 325), 0.2g of wetting agent Golden Group 127, 0.2g of leveling agent Golden Group 387, 36.6g of water, and 10g of resin-free red paste to make a red paint. Pour the paint onto the substrate surface, bake and cure, and visually observe the haze on the painted surface.

[0047] Mix 55g of water-soluble acrylic resin (Golden Group 5207N), 8g of amino resin (Cyttrium 325), 0.2g of wetting agent Golden Group 127, 0.2g of leveling agent Golden Group 387, 36.6g of water, and 8g of resin-free black paste to make a black paint. Pour the paint onto the substrate surface, bake and cure, and visually observe the haze on the painted surface.

[0048] Table 4. Fogging Effect of Water-Based Baking Paint

[0049] Mix 80g of water-based acrylic emulsion gold group 5811, 10.6g of water, 0.5g of pH adjuster Kejian DMEA, 8g of film-forming aid Kejian DPM, 0.2g of wetting agent gold group 127, 0.2g of leveling agent gold group 387, 0.5g of thickener gold group 4200, and 10g of resin-free red paste to prepare a water-based emulsion red paint. Pour it onto the substrate surface, allow it to dry and cure, and visually observe the haze on the paint film surface.

[0050] Mix 80g of water-based acrylic emulsion gold group 5811, 10.6g of water, 0.5g of pH adjuster Kejian DMEA, 8g of film-forming aid Kejian DPM, 0.2g of wetting agent gold group 127, 0.2g of leveling agent gold group 387, 0.5g of thickener gold group 4200, and 8g of resin-free black paste to prepare a water-based emulsion black paint. Pour it onto the substrate surface, allow it to dry and cure, and visually observe the haze on the paint film surface.

[0051] Table 5. Paint film haze conditions

[0052] Figure 1 Images of the resin-free red paste baking paint show that the resin-free red paste and baking paint prepared by using dispersant 6600 as the main dispersant and in combination with the wetting and dispersing agent prepared in Example 1 exhibit the best transparency and truly demonstrate the vibrancy of the red powder itself.

[0053] Figure 2 Images of resin-free black paste baking paint show that, using dispersant 6600 as the main dispersant and combined with the wetting and dispersing agent prepared in Example 1, the resulting resin-free black paste and baking paint have better blackness and higher gloss.

[0054] Figure 3 Images of the resin-free brown paste baking paint show that, using dispersant 6600 as the main dispersant and combined with the wetting and dispersing agent prepared in Example 1, the resulting resin-free brown paste and baking paint exhibit better transparency, showcasing the translucency of the transparent brown.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a wetting and dispersing agent, characterized in that, The preparation method includes: (1) Add benzidine disulfonic acid, 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid and glutaraldehyde aqueous solution to dimethyl sulfoxide, stir the reaction, add ethanol, filter and wash the product, dry to obtain the dispersant precursor; (2) Add dispersant precursor and sodium borohydride to ethanol, stir to react, add water to dilute, add sodium hydroxide, stir and heat to evaporate, precipitate, cool in ice water bath, filter, wash and dry to obtain wetting dispersant.

2. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The ratio of benzidine disulfonic acid, 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid, and glutaraldehyde in (1) is (0.4-0.7) mol: (0.3-0.6) mol: 1 mol.

3. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The reaction temperature in (1) is 70-85℃ and the reaction time is 18-24h.

4. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The ratio of the dispersant precursor and sodium borohydride in (2) is 100g:(18-24)g.

5. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The reaction temperature in (2) is 20-30℃ and the reaction time is 5-8h.

6. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, Sodium hydroxide is added to (2) to adjust the pH of the solution to 8-9.

7. The method for preparing the wetting and dispersing agent according to claim 2, characterized in that, The preparation method of 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid is as follows: 1,7-bis-Boc-1,4,7-triazaheptane and succinic anhydride are added to dichloromethane in a ratio of 1 mol: (1.4-1.6) mol. The mixture is stirred and reacted at 20-30℃ for 12-18 h. After vacuum distillation and washing, the product is added to a dichloromethane solution of trifluoroacetic acid. The mixture is stirred and reacted at 20-30℃ for 2-3 h. After vacuum distillation, the product is washed and recrystallized to obtain 4-[bis(2-aminoethyl)amino]-4-oxobutyric acid.

8. A wetting and dispersing agent obtained by the preparation method according to any one of claims 1-7.

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