A water-based dispersant and its preparation method

Abstract

This invention relates to the field of C09D11 / 38 dispersants, and more specifically, provides an aqueous dispersant and its preparation method. The aqueous dispersant provided by this invention comprises: ethyl polyethylene glycol, tert-butyl polyethylene glycol, naphthyl polyethylene glycol, and deionized water. It can be adsorbed onto the surface of pigment particles through different anchoring groups, and further enhanced by steric hindrance groups, allowing the pigment particles to maintain a stable dispersion state while retaining low viscosity, thus improving the performance of the aqueous dispersant. Furthermore, it imparts excellent gloss and color strength to the pigment, making it suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of CO9D11 / 38 dispersants, and more specifically, this invention provides an aqueous dispersant and a method for preparing the same. Background Technology

[0002] Dispersants can effectively wet, disperse, and stabilize pigments in a system. They can be widely used in water-based coatings, water-based inks, and water-based general-purpose color pastes. As people's environmental requirements increase, the demand for water-based coatings and water-based inks that do not contain volatile organic compounds is constantly increasing. Therefore, it is of great significance to guide the screening and even design of dispersants.

[0003] Traditional dispersants are mainly used in solvent-based systems. In addition, traditional dispersants can exhibit certain dispersing and stabilizing effects. However, due to their small molecular weight, they have a weak ability to fixate solid particles and cannot provide sufficient steric hindrance for solid particles. Therefore, they are not particularly firmly adsorbed on the surface of pigment particles and are very easy to desorb from the particle surface, causing the well-dispersed particles to re-flocculate and destroy the storage stability of the coating.

[0004] Patent application CN201710896456.4 discloses an aqueous dispersant for ceramic pigments and its preparation method. The aqueous pigment paste prepared in this application has a good dispersing effect on ceramic pigments through the hydrolysis of oligomers by phosphate groups, isocyanate terminal groups, and silane coupling agents, under the action of wetting agents. However, the polyether macromonomer used in this patent is not very environmentally friendly, which limits the large-scale production of the aqueous dispersant for ceramic pigments.

[0005] In this invention, the prepared dispersant can be adsorbed onto the surface of pigment particles through different anchoring groups, and then, through steric hindrance groups, the pigment particles can maintain a stable dispersion state while keeping the viscosity low, thus improving the performance of the water-based dispersant. Furthermore, it gives the pigment excellent gloss and coloring strength, making it suitable for industrial production. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an aqueous dispersant, the raw materials of which include: ethyl polyethylene glycol, tert-butyl polyethylene glycol, naphthyl polyethylene glycol, and deionized water.

[0007] As a preferred embodiment, the molecular formula of the ethyl polyethylene glycol is: n = 4 - 8.

[0008] As a preferred embodiment, the molecular formula of the tert-butyl polyethylene glycol is: n = 8 - 10.

[0009] As a preferred embodiment, the molecular formula of the naphthyl polyethylene glycol is: (n = 15 - 20) and

[0010] (n = 10 - 20).

[0011] Note: The chemical formulas of the raw materials disclosed in this application are derived theoretically.

[0012] As a preferred embodiment, the method for preparing ethyl polyethylene glycol mainly includes the following steps:

[0013] (1) Place ethanol and sodium ethoxide catalyst in a high-pressure reactor, seal the lid, and purge the air in the reactor and pipeline with inert gas at least three times; start stirring and heat the high-pressure reactor at the same time.

[0014] (2) When the autoclave reaches a certain temperature, add ethylene oxide dropwise, and control the pressure inside the autoclave to not exceed 0.4 MPa and the temperature inside the autoclave to not exceed 120℃.

[0015] (3) After the addition is complete, continue the reaction and cool down.

[0016] (4) Add acid to neutralize to pH 7, filter, and obtain ethyl polyethylene glycol.

[0017] As a preferred embodiment, the inert gas is one or more of nitrogen and argon.

[0018] As a preferred embodiment, the molar ratio of ethanol, sodium ethoxide catalyst, and ethylene oxide is 1:(0.013-0.014):(6-10).

[0019] As a preferred embodiment, the temperature of the autoclave in step (2) is 95-105°C.

[0020] As a preferred embodiment, the ethylene oxide is added in step (2) over a period of 3-4 hours.

[0021] As a preferred option, the conditions for continuing the reaction in step (3) are: a reaction temperature of 110-120°C and a reaction time of 0.5-1.5 h.

[0022] As a preferred option, the cooling temperature in step (3) is 85-95°C.

[0023] As a preferred embodiment, the acid in step (4) is one or more of acetic acid, hydrochloric acid, and citric acid.

[0024] As a preferred option, the acid in step (4) is acetic acid.

[0025] As a preferred embodiment, the preparation method of the tert-butyl polyethylene glycol mainly includes the following steps:

[0026] (1) Place tert-butanol and sodium tert-butanol catalyst in a high-pressure reactor, seal the lid, purge the air in the reactor and pipeline with inert gas more than three times, start stirring and heat the high-pressure reactor at the same time.

[0027] (2) When the autoclave reaches a certain temperature, add ethylene oxide dropwise, and control the pressure inside the autoclave to not exceed 0.4 MPa and the temperature inside the autoclave to not exceed 130℃;

[0028] (3) After the addition is complete, continue the reaction and cool down;

[0029] (4) Add acid to neutralize to pH 7, filter, and obtain tert-butyl polyethylene glycol.

[0030] As a preferred embodiment, the inert gas is one or more of nitrogen and argon.

[0031] As a preferred embodiment, the molar ratio of tert-butanol, sodium tert-butoxide, and ethylene oxide is 1:0.015-0.016:10-12.

[0032] As a preferred embodiment, the temperature of the autoclave in step (2) is 100-110°C.

[0033] As a preferred embodiment, the ethylene oxide is added at a rate of 3-4 h in step (2).

[0034] As a preferred option, the conditions for continuing the reaction in step (3) are: a reaction temperature of 120-125°C and a reaction time of 0.5-1.5 h.

[0035] As a preferred option, the cooling temperature in step (3) is 85-95°C.

[0036] As a preferred embodiment, the acid in step (4) is one or more of acetic acid, hydrochloric acid, and citric acid.

[0037] As a preferred option, the acid in step (4) is acetic acid.

[0038] As a preferred embodiment, the preparation method of the naphthyl polyethylene glycol mainly includes the following steps:

[0039] (1) Add 2-naphthol and potassium hydroxide into a high-pressure reactor, evacuate, replace with inert gas more than three times, and heat to 70-75℃.

[0040] (2) Add ethylene oxide dropwise and keep the temperature at 100-110℃.

[0041] (3) After the addition is complete, continue the reaction and cool down; add 2,6-dihydroxynaphthalene and stir to dissolve.

[0042] (4) After dissolution, evacuate the vacuum and replace with inert gas more than three times. Continue to add ethylene oxide dropwise while maintaining the temperature at 110°C. After the addition is complete, continue the reaction and cool down.

[0043] (5) Decolorization.

[0044] As a preferred embodiment, the inert gas is nitrogen.

[0045] As a preferred embodiment, the molar ratio of 2-naphthol, potassium hydroxide, and ethylene oxide in step (2) is 1:0.02 to 0.04:10.

[0046] As a preferred embodiment, the specific implementation method of continuing the reaction in step (3) is as follows: the reaction temperature is 125-135℃ and the reaction time is 0.5-1.5h.

[0047] As a preferred embodiment, the cooling temperature in step (3) is 90–100°C. The molar ratio of 2,6-dihydroxynaphthalene to 2-naphthol is 0.5:1, and the molar ratio of ethylene oxide to 2-naphthol in step (4) is 15–30:1.

[0048] As a preferred embodiment, the specific implementation method of continuing the reaction in step (4) is as follows: the reaction temperature is 125-135℃ and the reaction time is 0.5-1.5h.

[0049] As a preferred embodiment, the decolorization is specifically achieved by slowly adding hydrogen peroxide at 10% of the total amount of naphthyl polyethylene glycol for decolorization.

[0050] A second aspect of the present invention provides a method for preparing an aqueous dispersant, the steps of which include:

[0051] (1) Mix ethyl polyethylene glycol, tert-butyl polyethylene glycol and naphthyl polyethylene glycol evenly;

[0052] (2) Dissolve in deionized water to prepare a solution with a solid content of 30-40%;

[0053] (3) Cool to room temperature to obtain the aqueous dispersant.

[0054] As a preferred embodiment, the weight ratio of ethyl polyethylene glycol, tert-butyl polyethylene glycol and naphthyl polyethylene glycol is (1-2):(1-3):1.

[0055] Beneficial effects:

[0056] 1. The present invention provides The preparation method uses ethanol and ethylene oxide as raw materials. When the molar ratio of ethanol to ethylene oxide is 1:(6-10), and by strictly controlling the dropping rate of ethylene oxide at 3-4 h and the amount of sodium ethoxide added, the efficiency is effectively improved. The dispersion effect.

[0057] 2. The present invention provides The preparation method uses tert-butanol and ethylene oxide as raw materials. When the molar ratio of tert-butanol to ethylene oxide is 1:(10-12), and the reaction temperature is strictly controlled, the stability of the pigment in the aqueous dispersion system can be effectively improved.

[0058] 3. The method for preparing naphthyl polyethylene glycol provided by the present invention uses 2-naphthol and ethylene oxide as raw materials, and first prepares... The obtained naphthylethylene glycol was used to dissolve 2,6-dihydroxynaphthalene, and then an addition reaction was carried out with ethylene oxide to prepare a product containing... (n = 15 - 20) and

[0059] The (n=10-20) structure exhibits good hydrophilicity and is a superdispersant with a naphthalene ring structure similar to that of pigments. Furthermore, maintaining the temperature at 100–110°C during the dropwise addition of ethylene oxide reduces the formation of byproducts, resulting in a product with a light color. Its high molecular weight... (n = 15 - 20) and

[0060] (n=10-20) effectively improves the storage stability of water-based dispersants, while also improving the gloss and color strength of pigments in water-based dispersible pastes.

[0061] 4. By limiting the weight ratio of ethyl polyethylene glycol, tert-butyl polyethylene glycol and naphthyl polyethylene glycol to (1-2):(1-3):1, the present invention improves the coloring strength and gloss of the pigment while maintaining a low viscosity.

[0062] 5. The aqueous dispersant prepared by this invention exhibits low viscosity in aqueous ink systems. Furthermore, through the synergistic effect of naphthyl, ethyl tert-butyl, hydroxyl, and ethoxy segments, it not only overcomes the high viscosity caused by the large molecular weight of polymeric dispersants but also allows for stable coexistence among pigments. The synergistic effect between the naphthyl, ethyl, tert-butyl, and ethoxy segments and the functional groups of the pigments in the aqueous ink system results in excellent gloss and color strength for the pigments. Moreover, it is suitable for industrial production. Detailed Implementation

[0063] Example

[0064] Example 1

[0065] Example 1 provides an aqueous dispersant, the raw materials of which include: ethyl polyethylene glycol, tert-butyl polyethylene glycol, naphthyl polyethylene glycol, and deionized water.

[0066] The method for preparing the ethyl polyethylene glycol includes the following steps:

[0067] (1) Place 46 kg of ethanol and 0.92 kg of sodium ethoxide in a high-pressure reactor, seal the lid, purge the air in the reactor and pipeline with nitrogen four times, start stirring and heat the high-pressure reactor at the same time.

[0068] (2) When the pressure vessel reaches a certain temperature, add 352 kg of ethylene oxide dropwise over a period of 4 hours. The reaction temperature is 100°C, and the pressure inside the vessel is controlled to not exceed 0.4 MPa.

[0069] (3) After the addition is complete, continue the reaction at a temperature of 115℃ for 1.0 h, and then cool down to 90℃.

[0070] (4) Add acetic acid to neutralize to pH 7, filter, and you will get ethyl polyethylene glycol.

[0071] The molecular formula of the ethyl polyethylene glycol is: n = 6.

[0072] The method for preparing the tert-butyl polyethylene glycol includes the following steps:

[0073] (1) Place 74 kg of tert-butanol and 1.48 kg of sodium tert-butoxide in a high-pressure reactor, seal the lid, purge the air in the reactor and pipeline with nitrogen four times, start stirring and heat the high-pressure reactor at the same time.

[0074] (2) When the autoclave reaches a certain temperature, add 528 kg of ethylene oxide dropwise over a period of 4 hours. The reaction temperature is 105°C, and the pressure inside the autoclave is controlled to not exceed 0.4 MPa.

[0075] (3) After the addition is complete, continue the reaction at a temperature of 120°C for 1.0 h, and then cool down to 90°C.

[0076] (4) Add acetic acid to neutralize to pH 7, filter, and the product is tert-butyl polyethylene glycol.

[0077] The molecular formula of the tert-butyl polyethylene glycol is: n = 10.

[0078] The method for preparing the naphthyl polyethylene glycol includes the following steps:

[0079] (1) Put 144 kg of 2-naphthol and 1.12 kg of potassium hydroxide into a high-pressure reactor, evacuate, replace with nitrogen four times, and heat to 70°C.

[0080] (2) Add 440 kg of ethylene oxide dropwise and keep the temperature at 105 °C.

[0081] (3) After the addition is complete, continue the reaction for 0.5 h at a reaction temperature of 130 °C, then cool down to 95 °C. Add 80 kg of 2,6-dihydroxynaphthalene. Stir to dissolve.

[0082] (4) After dissolution, vacuum the gas and replace it with nitrogen four times. Add 880 kg of ethylene oxide dropwise while maintaining the temperature at 105 °C. After the addition is complete, continue the reaction for 1 hour at a temperature of 130 °C, then cool down to 100 °C.

[0083] (5) Add 10% of the total amount of naphthyl polyethylene glycol in hydrogen peroxide for decolorization.

[0084] The molecular formula of the naphthyl polyethylene glycol is: (n=15) and

[0085] (n=15)

[0086] The second aspect of this embodiment 1 provides a method for preparing an aqueous dispersant, the steps of which include:

[0087] (1) Mix ethyl polyethylene glycol, tert-butyl polyethylene glycol and naphthyl polyethylene glycol evenly;

[0088] (2) Dissolve in deionized water to prepare a solution with a solid content of 35%;

[0089] (3) Cool to room temperature to obtain the aqueous dispersant.

[0090] The weight ratio of ethyl polyethylene glycol, tert-butyl polyethylene glycol, and naphthyl polyethylene glycol is 1.5:2:1; the amount of ethyl polyethylene glycol added is 40 kg.

[0091] Example 2

[0092] Example 2 provides an aqueous dispersant, the raw materials of which include: ethyl polyethylene glycol, tert-butyl polyethylene glycol, naphthyl polyethylene glycol, and deionized water. The preparation method of the ethyl polyethylene glycol includes the following steps:

[0093] (1) Place 46 kg of ethanol and 0.95 kg of sodium ethoxide in a high-pressure reactor, seal the lid, purge the air in the reactor and pipeline with nitrogen four times, start stirring and heat the high-pressure reactor at the same time.

[0094] (2) When the autoclave reaches a certain temperature, add 264 kg of ethylene oxide dropwise over a period of 4 hours. The reaction temperature is 95°C and the pressure inside the autoclave is controlled to not exceed 0.4 MPa.

[0095] (3) After the addition is complete, continue the reaction at a temperature of 110℃ for 1.0 h, and then cool down to 90℃.

[0096] (4) Add acetic acid to neutralize to pH 7, filter, and you will get ethyl polyethylene glycol.

[0097] The molecular formula of the ethyl polyethylene glycol is: n = 4.

[0098] The method for preparing the tert-butyl polyethylene glycol includes the following steps:

[0099] (1) Place 74 kg of tert-butanol and 1.53 kg of sodium tert-butoxide in a high-pressure reactor, seal the lid, purge the air in the reactor and pipeline with nitrogen four times, start stirring and heat the high-pressure reactor at the same time.

[0100] (2) When the pressure vessel reaches a certain temperature, add 440 kg of ethylene oxide dropwise over a period of 4 hours. The reaction temperature is 105°C, and the pressure inside the vessel is controlled to not exceed 0.4 MPa.

[0101] (3) After the addition is complete, continue the reaction at a temperature of 120°C for 1.0 h, and then cool down to 90°C.

[0102] (4) Add acetic acid to neutralize to pH 7, filter, and the product is tert-butyl polyethylene glycol.

[0103] The molecular formula of the tert-butyl polyethylene glycol is: n = 8.

[0104] The method for preparing the naphthyl polyethylene glycol includes the following steps:

[0105] (1) Put 144 kg of 2-naphthol and 1.68 kg of potassium hydroxide into a high-pressure reactor, evacuate, replace with nitrogen four times, and heat to 70°C.

[0106] (2) Add 440 kg of ethylene oxide dropwise and keep the temperature at 105 °C.

[0107] (3) After the addition is complete, continue the reaction for 0.5 h at a reaction temperature of 130 °C, then cool down to 95 °C. Add 80 kg of 2,6-dihydroxynaphthalene. Stir to dissolve.

[0108] (4) After dissolution, vacuum the gas and replace it with nitrogen four times. Add 1100 kg of ethylene oxide dropwise while maintaining the temperature at 105 °C. After the addition is complete, continue the reaction for 1.5 h at a reaction temperature of 130 °C, then cool down to 100 °C.

[0109] (5) Add 10% of the total amount of naphthyl polyethylene glycol in hydrogen peroxide for decolorization.

[0110] The molecular formula of the naphthyl polyethylene glycol is: (n=18) and

[0111] (n=17)

[0112] The second aspect of this embodiment 2 provides a method for preparing an aqueous dispersant, the steps of which include:

[0113] (1) Mix ethyl polyethylene glycol, tert-butyl polyethylene glycol and naphthyl polyethylene glycol evenly;

[0114] (2) Dissolve in deionized water to prepare a solution with a solid content of 35%;

[0115] (3) Cool to room temperature to obtain the aqueous dispersant.

[0116] The weight ratio of ethyl polyethylene glycol, tert-butyl polyethylene glycol, and naphthyl polyethylene glycol is 2:3:1; the amount of ethyl polyethylene glycol added is 40 kg.

[0117] Example 3

[0118] Example 3 provides an aqueous dispersant, with the same implementation method as Example 2. The difference is that the weight ratio of ethyl polyethylene glycol, tert-butyl polyethylene glycol, and naphthyl polyethylene glycol is 2:1:1; and the amount of ethyl polyethylene glycol added is 40 kg.

[0119] Comparative Example 1

[0120] Comparative Example 1 provides a dispersant, which was purchased from Shanghai Kaiyin Chemical Co., Ltd. as Solsperse 27000.

[0121] Comparative Example 2:

[0122] Comparative Example 2 provides an aqueous dispersant, implemented in the same manner as Example 2. The difference lies in the weight ratio of ethyl polyethylene glycol, tert-butyl polyethylene glycol, and naphthyl polyethylene glycol being 3:4:1.

[0123] Performance testing:

[0124] The aqueous dispersants prepared in Examples 1-3 and Comparative Examples 1-2 were applied to the testing of aqueous inks: 35 parts by weight of pigment, 35 parts by weight of waterborne acrylic resin Joncryl 678 (30%), 2 parts by weight of aqueous dispersant, 0.3 parts by weight of defoamer, 27.7 parts by weight of water, and 150 parts by weight of 2-3 mm glass beads were mixed and dispersed in a shaker for 60 minutes to obtain the aqueous ink. A diluted color was obtained by mixing the aqueous ink and white Nippon paint at a ratio of 1:19. The aqueous ink was then applied to coated paper using a No. 6 wire rod to obtain coated paper coated with the aqueous ink. The diluted color was then applied to the coated paper using a No. 10 wire rod to obtain coated paper coated with the diluted color.

[0125] (1) Color: The color difference of the coated paper coated with water-based ink was detected using an X-Rite colorimeter;

[0126] (2) Coloring strength: The coloring strength of the coated paper with diluted color was tested using an X-Rite colorimeter;

[0127] (3) Gloss: The gloss of the coated paper coated with water-based ink was tested using a JFL-BZ60° gloss meter.

[0128] (4) Viscosity: Stir the water-based ink evenly and adjust the temperature to 25°C. Use a Cotton 4 viscosity cup to test the flow time of the ink.

[0129] Table 1 shows the test results of the color, tinting strength, and gloss of the prepared water-based ink. Table 2 shows the viscosity test results of the prepared water-based ink.

[0130] Table 1. Color, tinting strength, and gloss of the prepared water-based inks

[0131]

[0132] Table 2 Viscosity values ​​of the prepared water-based ink

[0133] dispersant Viscosity value, S CI Pigment Red 146 Comparative Example 1 135 Example 1 39 CI Pigment Blue 15:3 Comparative Example 2 45 Example 2 24 CI Pigment Black 7 Comparative Example 1 375 Example 3 58

[0134] The experimental results show that the water-based dispersant prepared by this invention exhibits good vividness, high tinting strength and gloss in CI Pigment Red 146, CI Pigment Blue 15:3 and CI Pigment Black 7, and the prepared water-based ink has relatively low viscosity.

Claims

1. An aqueous dispersant characterized by, Raw materials include: ethyl polyethylene glycol, tert-butyl polyethylene glycol, naphthyl polyethylene glycol, and deionized water; The molecular formula of the naphthyl polyethylene glycol is , n = 15-20; and , n = 10-20; The weight ratio of ethyl polyethylene glycol, tert-butyl polyethylene glycol and naphthyl polyethylene glycol is (1~2):(1-3):

1.

2. The aqueous dispersant according to claim 1, characterized in that, The ethyl polyethylene glycol has a molecular formula of n = 4-8.

3. The aqueous dispersant according to claim 1, characterized in that, The molecular formula of the tert-butyl polyethylene glycol is n = 8-10.

4. The aqueous dispersant of claim 2, wherein, The method for preparing the ethyl polyethylene glycol includes the following steps: (1) Place ethanol and sodium ethoxide in a high-pressure reactor, seal the lid, and purge the air in the reactor and pipeline with inert gas at least three times; start stirring and heat the high-pressure reactor at the same time. (2) When the autoclave reaches a certain temperature, add ethylene oxide dropwise, and control the pressure inside the autoclave to not exceed 0.4 MPa and the temperature inside the autoclave to not exceed 120℃; (3) After the addition is complete, continue the reaction and cool down; (4) Add acid to neutralize to pH 7, then filter to obtain ethyl polyethylene glycol.

5. The aqueous dispersant of claim 4, wherein, The molar ratio of ethanol, sodium ethoxide, and ethylene oxide is 1:(0.013~0.014):(6~10).

6. The aqueous dispersant of claim 1, wherein, The method for preparing the naphthyl polyethylene glycol includes the following steps: (1) Add 2-naphthol and potassium hydroxide into a high-pressure reactor, evacuate, replace with inert gas more than three times, and heat to 70~75℃; (2) Add ethylene oxide dropwise, keeping the temperature at 100~110℃; (3) After the addition is complete, continue the reaction and cool down; add 2,6-dihydroxynaphthalene and stir to dissolve; (4) After dissolving, evacuate the vacuum and replace with inert gas more than three times. Continue to add ethylene oxide dropwise while maintaining the temperature at 100~110℃. After the addition is completed, continue the reaction and cool down. (5) Decolorization.

7. The aqueous dispersant of claim 6, wherein, The molar ratio of 2-naphthol, potassium hydroxide, and ethylene oxide in step (2) is 1:0.02~0.04:10; the molar ratio of 2,6-dihydroxynaphthalene to 2-naphthol is 0.5:1; and the molar ratio of ethylene oxide to 2-naphthol in step (4) is 15~30:

1.

8. A method for preparing an aqueous dispersant according to any one of claims 1 to 7, characterized in that, The preparation steps of the aqueous dispersant include: (1) Mix ethyl polyethylene glycol, tert-butyl polyethylene glycol and naphthyl polyethylene glycol evenly; (2) Dissolve in deionized water to prepare a solution with a solid content of 30-40%; (3) Cool to room temperature to obtain the aqueous dispersant.

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