A high molecular dispersant for paints and a method for preparing the same

Abstract

This invention belongs to the field of building admixture technology, specifically relating to a polymeric dispersant for use in coatings and its preparation method. The polymeric dispersant, by weight, comprises: 100 parts of ester macromonomer, 2-7 parts of polyfluoroamide monomer, 0.9-1.5 parts of emulsifier, 0.5-2.5 parts of oxidant, 0.5-3 parts of reducing agent, 0.8-2.5 parts of chain transfer agent, 4-13 parts of acrylic acid, 4-8 parts of tert-butyl monomer, and 170-200 parts of water. The polymeric dispersant prepared by this invention exhibits excellent viscosity retention at low dosages; it significantly improves the dispersion effect of particles in coating systems, reducing the phenomena of flocculation, agglomeration, and difficulty in dispersion. Furthermore, the preparation process provided by this invention is simple to operate, has mild reaction conditions, is easy to scale up for production, and the production process is safe, environmentally friendly, and pollution-free.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building admixtures, in particular to a high molecular dispersant for paint and a preparation method thereof. BACKGROUND

[0002] Dispersants are a kind of important additives widely used in paint. Most of the paint exists in the form of agglomerates and aggregates of primary particles. If these pigment particles of different sizes cannot be dispersed into smaller particles or primary particles and become a stable dispersion system that does not aggregate or flocculate, defects such as flocculation, precipitation, color bloom, reduced gloss, and decreased tinting and hiding power will occur. Meanwhile, the fillers in paint are generally inorganic materials with large particle sizes. The inorganic fillers with large particle sizes are relatively easy to disperse because of their small specific surface area and weak adsorption capacity. However, the large internal pores of the paint formed by large particle size fillers allow harmful substances to easily enter, thereby reducing the overall service life of the paint. On the other hand, small particle size materials have stronger cohesion and are difficult to disperse, resulting in poor paint flowability. Therefore, if more small molecule materials are needed to make the internal structure of the paint more compact, dispersants with better dispersing performance are needed. Dispersants with different functional groups and polymer chain structures have been developed. The dispersant wets and adsorbs on the particle surface through the hydrophobic group at one end, and the hydrophilic group at the other end is combined with the solvent medium, thereby reducing the adhesion between particles, preventing flocculation or aggregation, and forming a stable dispersion suspension of paint fillers. With the development of the paint industry, various types of paint dispersants have appeared in China. Commonly used dispersants in aqueous solution mainly include high molecular electrolyte dispersants and polycarboxylic acid and its derivative dispersants. However, these dispersants have insufficient dispersing effect in actual use, and problems such as increased viscosity and particle aggregation easily occur. Some paint manufacturers prefer to use foreign products such as BYK, Lubrizol, DuPont, and Dow.

[0003] Therefore, it is of great importance to develop a high molecular dispersant for paint to increase the paint application performance, improve the paint application performance, and reduce particle aggregation, which promotes the popularization of paint. SUMMARY

[0004] Therefore, it is of great importance to develop a high molecular dispersant for paint to increase the paint application performance, improve the paint application performance, and reduce particle aggregation, which promotes the popularization of paint.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] In a first aspect, the present invention provides a polymeric dispersant for use in coatings, said polymeric dispersant comprising, by weight: 80-120 parts of ester macromonomer, 2-10 parts of polyfluoroamide monomer, 0.7-1.8 parts of emulsifier, 0.5-3 parts of oxidant, 0.5-4 parts of reducing agent, 0.6-3 parts of chain transfer agent, 3-16 parts of acrylic acid, 3-10 parts of tert-butyl monomer, and 130-240 parts of water.

[0007] Further, the polymeric dispersant comprises, by weight: 100 parts ester macromonomer, 2-7 parts polyfluoroamide monomer, 0.9-1.5 parts emulsifier, 0.5-2.5 parts oxidant, 0.5-3 parts reducing agent, 0.8-2.5 parts chain transfer agent, 4-13 parts acrylic acid, 4-8 parts tert-butyl monomer, and 170-200 parts water.

[0008] Further, the polymeric dispersant comprises, by weight: 100 parts ester macromonomer, 5 parts polyfluoroamide monomer, 1.35-1.5 parts emulsifier, 0.9-2.5 parts oxidant, 1-1.5 parts reducing agent, 1.3-2.5 parts chain transfer agent, 6-13 parts acrylic acid, 6.5-8 parts tert-butyl monomer, and 180-200 parts water.

[0009] In some embodiments, the ester macromonomer is one of the following: polyethylene glycol monomethoxy ether monomethacrylate, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, and polyethylene glycol monomethacrylate, with a molecular weight of 1000-3000.

[0010] In some embodiments, the tert-butyl monomer is 1-(tert-butyldimethylsiloxy)-1-methoxyethylene.

[0011] Furthermore, the emulsifier is composed of sodium dodecylbenzenesulfonate and diethylene glycol monolaurate in a mass ratio of 1:2.

[0012] Furthermore, the oxidant is one of ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, and tert-butyl hydroperoxide.

[0013] Furthermore, the reducing agent is one of sodium bisulfite, ascorbic acid, disodium 2-hydroxy-2-sulfoacetate, or glucose.

[0014] Further, the chain transfer agent is one of mercaptopropionic acid, mercaptoethanol, sodium formate, dithiobenzoic acid butyrate, mercaptopropionic acid, or trisodium phosphate.

[0015] In some embodiments, the mass ratio of the ester macromonomer, polyfluoroamide monomer, acrylic acid and tert-butyl monomer is 100:(2-7):(4-13):(4-8).

[0016] In some embodiments, the amount of oxidant is 0.5%-2.5% of the total mass of the ester macromonomers, the amount of reducing agent is 0.5%-3% of the total mass of the ester macromonomers, the amount of chain transfer agent is 0.8%-2.5% of the total mass of the ester macromonomers, and the amount of organic solvent is 25%-50% of the total mass of the unsaturated acid and polyfluorinated monomer.

[0017] In a second aspect, the present invention provides a polyfluoroamide monomer, the structural formula of which is as follows:

[0018]

[0019] In some embodiments, a method for preparing the polyfluoroamide monomer is provided, comprising the following steps: adding an unsaturated acid, a polyfluoroamide monomer, a catalyst, a polymerization inhibitor, and an organic solvent into a reaction vessel equipped with a reflux condenser and mixing them, adjusting the temperature to 75-95°C, distilling under reduced pressure for 4-6 hours, and removing the organic solvent by vacuum after the reaction is completed to obtain the polyfluoroamide monomer.

[0020] Further, by weight, it includes: 100 parts unsaturated acid, 45-250 parts 3-tetrafluoroethoxyaniline, 1-9 parts catalyst, 1.5-3.5 parts polymerization inhibitor, and 70-100 parts organic solvent.

[0021] Furthermore, the unsaturated acid is one of acrylic acid and methacrylic acid.

[0022] Furthermore, the catalyst is one of methylbenzenesulfonic acid, concentrated sulfuric acid, aluminum trichloride, and phosphoric acid.

[0023] Further, the polymerization inhibitor is one of hydroquinone, 4-tert-butylcatechol, 2,6-di-tert-butyl-p-methylphenol, methylhydroquinone, 1,4-naphthoquinone, p-benzoquinone, and bisphenol A.

[0024] Furthermore, the organic solvent is carbon tetrachloride or diethyl ether.

[0025] The third aspect of the present invention provides a method for preparing a polymeric dispersant that can be used in coatings, comprising the following steps: adding an ester macromonomer, a polyfluoroamide monomer, an emulsifier, and water to a reaction vessel for pre-emulsification for 30 min; then adding 1 / 4 of an oxidant solution, 1 / 4 of a chain transfer agent and reducing agent mixed solution, and 1 / 4 of an acrylic acid and tert-butyl monomer mixed solution to the reaction vessel, heating to 45-55℃ and reacting for 1-1.5 h to obtain a seed emulsion; then simultaneously adding the remaining oxidant solution, chain transfer agent and reducing agent mixed solution, and acrylic acid and tert-butyl monomer mixed solution dropwise over 1-1.5 h; reacting at a constant temperature for 30 min; and after the reaction is completed, adding 32% liquid alkali to adjust the pH to 6-7.

[0026] Furthermore, the acrylic acid and tert-butyl monomer mixed solution includes acrylic acid and 1-(tert-butyldimethylsiloxy)-1-methoxyethylene.

[0027] The beneficial effects of this invention are as follows:

[0028] 1) This invention utilizes 3-tetrafluoroethoxyaniline with an unsaturated acid to undergo an amidation reaction to prepare a polyfluoroamide monomer, which then participates in a copolymerization reaction to incorporate multiple fluorine groups into the molecular structure. The high electronegativity of fluorine atoms enhances the adsorption capacity of the coating dispersant for pigments, thus improving early pigment dispersion and viscosity retention in the coating system, effectively reducing the formation of flocculated particles due to undispersed pigments. The amide groups, by enhancing the interaction with the pigment surface, help improve the compatibility between the dispersant and the pigment, thereby enhancing the overall dispersion effect.

[0029] 2) This invention introduces 1-(tert-butyldimethylsiloxy)-1-methoxyethylene, resulting in a molecular structure containing tert-butyl, siloxane, and methoxy groups. The tert-butyl group, as a large hydrophobic group, significantly increases the steric hindrance of the coating molecules, preventing tight molecular packing and improving the coating's flowability and dispersibility. The tert-butyl siloxane has high bond energy, increasing group stability, and also wets and reduces the surface tension of the coating, improving its flowability and application performance. The methoxy group enhances the interaction with the coating surface, helping to improve the compatibility between the dispersant and the coating, thereby improving the overall dispersion effect. By introducing a dispersant containing 1-(tert-butyldimethylsiloxy)-1-methoxyethylene, the tensile strength, bond strength, and impermeability of polymer cement waterproof coatings can be effectively improved.

[0030] 3) The process of this invention is simple to operate, the reaction conditions are mild, it is easy to scale up production, the production process is safe and pollution-free, and it is an environmentally friendly product. Detailed Implementation

[0031] The preferred embodiments of the present invention will be described in detail below with reference to specific examples. It should be noted that the specific embodiments given below are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and intent.

[0032] Unless otherwise specified, the experimental methods used in the following specific embodiments are conventional methods. Unless otherwise specified, the materials and reagents used in the following specific embodiments can be obtained from conventional commercial sources or prepared according to conventional methods in the art.

[0033] In some embodiments of the present invention, a polyfluoroamide monomer is used. The structural formula of the polyfluoroamide monomer is as follows:

[0034]

[0035] The polyfluoroamide monomer is prepared by esterification reaction of a monomer containing amine and polyfluoro groups with an unsaturated acid.

[0036] Furthermore, the preparation method of polyfluoroamide monomer includes the following reaction steps: adding unsaturated acid, 3-tetrafluoroethoxyaniline, catalyst, polymerization inhibitor and organic solvent into a reaction vessel equipped with a reflux condenser and mixing, adjusting the temperature to 75-95℃, and distilling under reduced pressure for 4-6 hours. After the reaction is completed, the organic solvent is removed by vacuum to obtain the polyfluoroamide monomer.

[0037] The structure of the 3-tetrafluoroethoxyaniline is as follows:

[0038]

[0039] The unsaturated acid is one of acrylic acid and methacrylic acid.

[0040] The catalyst is one of p-toluenesulfonic acid, concentrated sulfuric acid, aluminum trichloride, and phosphoric acid.

[0041] The polymerization inhibitor is one of hydroquinone, 4-tert-butylcatechol, 2,6-di-tert-butyl-p-methylphenol, methylhydroquinone, 1,4-naphthoquinone, p-benzoquinone, and bisphenol A.

[0042] The organic solvent is carbon tetrachloride or diethyl ether.

[0043] Based on the above reaction, the inventors used diethylenetriamine, which also contains amine groups and has the ability to adsorb pigment particles, as a substitute for 3-tetrafluoroethoxyaniline. However, tests revealed that after using diethylenetriamine to replace 3-tetrafluoroethoxyaniline in the preparation of polyfluoroamide monomers, the stability and dispersion ability of the coating decreased, meaning that the coating exhibited more severe particle agglomeration and accumulation. This indicates that 3-tetrafluoroethoxyaniline has an irreplaceable effect in the preparation of polyfluoroamide monomers.

[0044] Further, the molar ratio of the unsaturated acid to 3-tetrafluoroethoxyaniline is (1-5):1, the amount of catalyst is 0.5%-2.5% of the total mass of the unsaturated acid and polyfluorinated monomer, the amount of polymerization inhibitor is 0.7%-2% of the total mass of the unsaturated acid and polyfluorinated monomer, and the amount of organic solvent is 25%-50% of the total mass of the unsaturated acid and polyfluorinated monomer.

[0045] One embodiment of the present invention relates to a polymeric dispersant that can be used in coatings. Taking 100 parts of an ester macromonomer as an example, the polymeric dispersant comprises: 100 parts of an ester macromonomer, 2-7 parts of a polyfluoroamide monomer, 0.9-1.5 parts of an emulsifier, 0.5-2.5 parts of an oxidant, 0.5-3 parts of a reducing agent, 0.8-2.5 parts of a chain transfer agent, 4-13 parts of acrylic acid, 4-8 parts of a tert-butyl monomer, and 150-200 parts of water.

[0046] The polyfluoroamide monomer is prepared by the above reaction.

[0047] The ester macromonomer is one of the following: polyethylene glycol monomethoxy ether monomethacrylate, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, and polyethylene glycol monomethacrylate, with a molecular weight of 1000-3000.

[0048] The emulsifier is composed of sodium dodecylbenzenesulfonate and diethylene glycol monolaurate in a mass ratio of 1:2.

[0049] The oxidant is one of ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, and tert-butyl hydroperoxide.

[0050] The reducing agent is one of sodium bisulfite, ascorbic acid, disodium 2-hydroxy-2-sulfoacetate, or glucose.

[0051] The chain transfer agent is one of mercaptopropionic acid, mercaptoethanol, sodium formate, dithiobenzoic acid butyrate, mercaptopropionic acid, or trisodium phosphate.

[0052] The tert-butyl monomer is 1-(tert-butyldimethylsiloxy)-1-methoxyethylene.

[0053] Through research, the inventors discovered that 1-(tert-butyldimethylsiloxy)-1-methoxyethylene contains tert-butyl, methoxy, and siloxy groups, which produce an unexpected synergistic effect with other raw materials. This effect significantly improves the dispersion performance of particles in coating systems and effectively reduces the phenomena of flocculation, agglomeration, and difficulty in dispersion.

[0054] Further, the amount of oxidant is 0.5%-2.5% of the total mass of the ester macromonomers, the amount of reducing agent is 0.5%-3% of the total mass of the ester macromonomers, the amount of chain transfer agent is 0.8%-2.5% of the total mass of the ester macromonomers, and the amount of emulsifier is 0.9%-1.5% of the total mass of the ester macromonomers.

[0055] Furthermore, the mass ratio of the ester macromonomer, polyfluoroamide monomer, acrylic acid and tert-butyl monomer is 100:(2-7):(4-13):(4-8).

[0056] In some embodiments of the present invention, a method for preparing a polymeric dispersant suitable for coatings is disclosed. The method includes the following steps: pre-emulsifying an ester macromonomer, a polyfluoroamide monomer, an acyl chloride monomer, an emulsifier, and water in a reaction vessel for 30 minutes; then adding 1 / 4 of an oxidizing agent solution, 1 / 4 of a chain transfer agent and reducing agent mixture, and 1 / 4 of a acrylic acid and tert-butyl monomer mixture to the reaction vessel, heating to 50°C and reacting for 1 hour to obtain a seed emulsion; subsequently, simultaneously adding the remaining oxidizing agent solution, chain transfer agent and reducing agent mixture, and acrylic acid and tert-butyl monomer mixture dropwise over 120-200 minutes; maintaining a constant temperature for a period of time; and after the reaction is complete, adding 32% liquid alkali to adjust the pH to 6-7. This yields the polymeric dispersant suitable for coatings.

[0057] The following description is based on specific embodiments.

[0058] Example 1

[0059] This embodiment provides a polymeric dispersant that can be used in coatings and its preparation method, including a polyfluoroamide monomer and a formulation and preparation method for the coating dispersant. The following are the raw material composition and specific preparation method of the dispersant:

[0060] (1) Preparation of polyfluoroamide monomer: By weight, 100 parts of methacrylic acid, 48.6 parts of 3-tetrafluoroethoxyaniline, 2.23 parts of p-toluenesulfonic acid, 2.23 parts of 4-tert-butylcatechol and 74.3 parts of carbon tetrachloride were added to the first reaction vessel equipped with a reflux condenser and mixed. The temperature was adjusted to 85°C and the reaction was carried out under reduced pressure for 5 hours. After the reaction was completed, the organic solvent was removed by vacuum to obtain the polyfluoroamide monomer.

[0061] (2) Dispersant for coatings: By weight, 100 parts of polyethylene glycol monomethoxy ether monomethacrylate with a molecular weight of 1000, 5 parts of polyfluoroamide monomer acyl chloride monomer obtained in step (1), 0.5 parts of sodium dodecylbenzenesulfonate, 1 part of diethylene glycol monolaurate, and 133 parts of water are added to the second reaction vessel and stirred evenly. 0.9 parts of ammonium persulfate and 20 parts of water are mixed evenly to prepare the oxidant solution for the first dropping device; 1 part of disodium 2-hydroxy-2-sulfoacetic acid, 2.5 parts of trisodium phosphate, and 20 parts of water are mixed evenly to prepare the chain transfer agent and reducing agent mixed solution for the second dropping device; 13 parts of acrylic acid, 8 parts of 1-(tert-butyldimethylsiloxy)-1-methoxyethylene, and 20 parts of water are mixed evenly to prepare the acrylic acid and tert-butyl monomer mixed solution for the third dropping device.

[0062] After adding the raw materials to the second reaction vessel, pre-emulsify for 30 minutes. Then, add 1 / 4 mass fraction of the oxidant solution, 1 / 4 mass fraction of the chain transfer agent and reducing agent mixture, and 1 / 4 mass fraction of the acrylic acid and tert-butyl monomer mixture to the second reaction vessel, and heat to 50°C and react for 1 hour to obtain a seed emulsion. Simultaneously, add the remaining oxidant solution, chain transfer agent and reducing agent mixture, and acrylic acid and tert-butyl monomer mixture dropwise over 1.5 hours. React at a constant temperature for 30 minutes. After the reaction is complete, add 10 parts by weight of 32% sodium hydroxide to adjust the pH to 6-7. This yields a 40% concentration of the aforementioned polymeric dispersant suitable for coatings.

[0063] Example 2

[0064] This embodiment provides a polymeric dispersant that can be used in coatings and its preparation method, including a polyfluoroamide monomer and a formulation and preparation method for the coating dispersant. The following are the raw material composition and specific preparation method of the dispersant:

[0065] (1) Preparation of polyfluoroamide monomer: 100 parts by weight of acrylic acid, 96.3 parts by weight of 3-tetrafluoroethoxyaniline, 1 part by weight of concentrated sulfuric acid, 1.6 parts by weight of 4-tert-butylcatechol and 78.52 parts by weight of carbon tetrachloride were added to the first reaction vessel equipped with a reflux condenser and mixed. The temperature was adjusted to 95°C and the reaction was carried out under reduced pressure for 6 hours. After the reaction was completed, the organic solvent was removed by vacuum to obtain the polyfluoroamide monomer.

[0066] (2) Dispersant for coatings: By weight, 100 parts of polyethylene glycol monoacrylate with a molecular weight of 3000, 5 parts of polyfluoroamide monomer prepared in step (1), 0.45 parts of sodium dodecylbenzenesulfonate, 0.9 parts of diethylene glycol monolaurate, and 124 parts of water are added to the second reaction vessel and stirred evenly. 2.3 parts of hydrogen peroxide and 20 parts of water are mixed evenly to prepare the oxidant solution for the first dropping device; 1.5 parts of ascorbic acid, 1.3 parts of sodium formate, and 20 parts of water are mixed evenly to prepare the chain transfer agent and reducing agent mixed solution for the second dropping device; 6 parts of acrylic acid, 6.5 parts of 1-(tert-butyldimethylsiloxy)-1-methoxyethylene, and 20 parts of water are mixed evenly to prepare the acrylic acid and tert-butyl monomer mixed solution for the third dropping device.

[0067] The remaining operating steps are the same as in Example 1.

[0068] Example 3

[0069] This embodiment provides a polymeric dispersant that can be used in coatings and its preparation method, including a polyfluoroamide monomer and a formulation and preparation method for the coating dispersant. The following are the raw material composition and specific preparation method of the dispersant:

[0070] (1) Preparation of polyfluoroamide monomer: 100 parts by weight of methacrylic acid, 242.9 parts by weight of 3-tetrafluoroethoxyaniline, 8.6 parts by weight of p-toluenesulfonic acid, 3.1 parts by weight of p-benzoquinone and 85.73 parts by weight of carbon tetrachloride were added to the first reaction vessel equipped with a reflux condenser and mixed. The temperature was adjusted to 75°C and the reaction was carried out under reduced pressure for 4 hours. After the reaction was completed, the organic solvent was removed by vacuum to obtain the polyfluoroamide monomer.

[0071] (2) Dispersant for coatings: By weight, 100 parts of polyethylene glycol monomethoxy ether monoacrylate with a molecular weight of 2400, 2 parts of polyfluoroamide monomer obtained in step (1), 0.3 parts of sodium dodecylbenzenesulfonate, 0.6 parts of diethylene glycol monolaurate, and 116 parts of water are added to the second reaction vessel and stirred evenly. 0.5 parts of ammonium persulfate are mixed evenly with 20 parts of water to prepare the oxidant solution for the first dropping device; 2.7 parts of sodium bisulfite, 0.8 parts of butyric acid dithiobenzoate, and 20 parts of water are mixed evenly to prepare the chain transfer agent and reducing agent mixed solution for the second dropping device; 9 parts of acrylic acid, 4 parts of 1-(tert-butyldimethylsiloxy)-1-methoxyethylene, and 20 parts of water are mixed evenly to prepare the acrylic acid and tert-butyl monomer mixed solution for the third dropping device.

[0072] The remaining operating steps are the same as in Example 1.

[0073] Comparative Example 1

[0074] This comparative example provides a polymeric dispersant that can be used in coatings. The dispersant is identical to that in Example 1 except that no polyfluoroamide monomer is added.

[0075] Specifically, by weight, 100 parts of polyethylene glycol monomethoxy ether monomethacrylate with a molecular weight of 1000, 0.5 parts of sodium dodecylbenzenesulfonate, 1 part of diethylene glycol monolaurate, and 133 parts of water are added to the second reaction vessel and stirred until homogeneous. 0.9 parts of ammonium persulfate and 20 parts of water are mixed to prepare the oxidant solution for the first dropping device; 1 part of disodium 2-hydroxy-2-sulfoacetate, 2.5 parts of trisodium phosphate, and 20 parts of water are mixed to prepare the chain transfer agent and reducing agent mixture for the second dropping device; 13 parts of acrylic acid, 8 parts of 1-(tert-butyldimethylsiloxy)-1-methoxyethylene, and 20 parts of water are mixed to prepare the acrylic acid and tert-butyl monomer mixture for the third dropping device.

[0076] The remaining operating steps are the same as in Example 1.

[0077] Comparative Example 2

[0078] This comparative example provides a polymeric dispersant that can be used in coatings. In preparing the polyfluoroamide monomer, it is the same as in Example 1 except that the equimolar amount of 3-tetrafluoroethoxyaniline is replaced with diethylenetriamine.

[0079] Specifically, the preparation method of the polyfluoroamide monomer by weight is as follows: 100 parts of methacrylic acid, 24 parts of diethylenetriamine, 2.23 parts of p-toluenesulfonic acid, 2.23 parts of 4-tert-butylcatechol and 74.3 parts of carbon tetrachloride are added to a first reaction vessel equipped with a reflux condenser and mixed. The temperature is adjusted to 85°C, and the reaction is carried out under reduced pressure for 5 hours. After the reaction is completed, the organic solvent is removed by vacuum to obtain the polyfluoroamide monomer.

[0080] The remaining operating steps are the same as in Example 1.

[0081] Comparative Example 3

[0082] This comparative example provides a polymeric dispersant that can be used in coatings. In preparing the dispersant, it is the same as in Example 1 except that the polyfluoroamide monomer is replaced with trifluoroethyl methacrylate.

[0083] Specifically, by weight, 100 parts of polyethylene glycol monomethoxy ether monomethacrylate with a molecular weight of 1000, 5 parts of trifluoroethyl methacrylate, 0.5 parts of sodium dodecylbenzenesulfonate, 1 part of diethylene glycol monolaurate, and 133 parts of water are added to the second reaction vessel and stirred until homogeneous. 0.9 parts of ammonium persulfate and 20 parts of water are mixed to prepare the oxidant solution for the first dropping device; 1 part of disodium 2-hydroxy-2-sulfoacetate, 2.5 parts of trisodium phosphate, and 20 parts of water are mixed to prepare the chain transfer agent and reducing agent mixture for the second dropping device; 13 parts of acrylic acid, 8 parts of 1-(tert-butyldimethylsiloxy)-1-methoxyethylene, and 20 parts of water are mixed to prepare the acrylic acid and tert-butyl monomer mixture for the third dropping device.

[0084] The remaining operating steps are the same as in Example 1.

[0085] Comparative Example 4

[0086] This comparative example provides a polymeric dispersant that can be used in coatings. The dispersant is identical to that in Example 1 except that 1-(tert-butyldimethylsiloxy)-1-methoxyethylene is not added.

[0087] Specifically, by weight, 100 parts of polyethylene glycol monomethoxy ether monomethacrylate with a molecular weight of 1000, 5 parts of the polyfluoroamide monomer acyl chloride monomer obtained in step (1), 0.5 parts of sodium dodecylbenzenesulfonate, 1 part of diethylene glycol monolaurate, and 133 parts of water are added to the second reaction vessel and stirred evenly. 0.9 parts of ammonium persulfate and 20 parts of water are mixed evenly to prepare the oxidant solution for the first dropping device; 1 part of disodium 2-hydroxy-2-sulfoacetate, 2.5 parts of trisodium phosphate, and 20 parts of water are mixed evenly to prepare the chain transfer agent and reducing agent mixed solution for the second dropping device; 13 parts of acrylic acid and 20 parts of water are mixed evenly to prepare the acrylic acid and tert-butyl monomer mixed solution for the third dropping device.

[0088] The remaining operating steps are the same as in Example 1.

[0089] Comparative Example 5

[0090] This comparative example provides a polymeric dispersant that can be used in coatings. In preparing the dispersant, it is the same as in Example 1 except that 1-(tert-butyldimethylsiloxy)-1-methoxyethylene is replaced with vinyltriethoxysilane.

[0091] Specifically, by weight, 100 parts of polyethylene glycol monomethoxy ether monomethacrylate with a molecular weight of 1000, 5 parts of the polyfluoroamide monomer acyl chloride obtained in step (1), 0.5 parts of sodium dodecylbenzenesulfonate, 1 part of diethylene glycol monolaurate, and 133 parts of water are added to the second reaction vessel and stirred evenly. 0.9 parts of ammonium persulfate and 20 parts of water are mixed evenly to prepare the oxidant solution for the first dropping device; 1 part of disodium 2-hydroxy-2-sulfoacetate, 2.5 parts of trisodium phosphate, and 20 parts of water are mixed evenly to prepare the chain transfer agent and reducing agent mixed solution for the second dropping device; 13 parts of acrylic acid, 8 parts of vinyltriethoxysilane, and 20 parts of water are mixed evenly to prepare the acrylic acid and tert-butyl monomer mixed solution for the third dropping device.

[0092] The remaining operating steps are the same as in Example 1.

[0093] Comparative Example 6

[0094] This comparative example provides a polymeric dispersant that can be used in coatings. In preparing the dispersant, it is the same as in Example 1 except that 1-(tert-butyldimethylsiloxy)-1-methoxyethylene is replaced with allyloxy-tert-butyldimethylsilane.

[0095] Specifically, by weight, 100 parts of polyethylene glycol monomethoxy ether monomethacrylate with a molecular weight of 1000, 5 parts of the polyfluoroamide monomer acyl chloride obtained in step (1), 0.5 parts of sodium dodecylbenzenesulfonate, 1 part of diethylene glycol monolaurate, and 133 parts of water are added to the second reaction vessel and stirred evenly. 0.9 parts of ammonium persulfate and 20 parts of water are mixed evenly to prepare the oxidant solution for the first dropping device; 1 part of disodium 2-hydroxy-2-sulfoacetic acid, 2.5 parts of trisodium phosphate, and 20 parts of water are mixed evenly to prepare the chain transfer agent and reducing agent mixed solution for the second dropping device; 13 parts of acrylic acid, 8 parts of allyloxy-tert-butyldimethylsilane, and 20 parts of water are mixed evenly to prepare the acrylic acid and tert-butyl monomer mixed solution for the third dropping device.

[0096] The remaining operating steps are the same as in Example 1.

[0097] Comparative Example 7

[0098] This comparative example provides a polymeric dispersant that can be used in coatings. In preparing the dispersant, it is the same as in Example 1 except that 1-(tert-butyldimethylsiloxy)-1-methoxyethylene is replaced with 2-methoxypropylene.

[0099] Specifically, by weight, 100 parts of polyethylene glycol monomethoxy ether monomethacrylate with a molecular weight of 1000, 5 parts of the polyfluoroamide monomer acyl chloride monomer obtained in step (1), 0.5 parts of sodium dodecylbenzenesulfonate, 1 part of diethylene glycol monolaurate, and 133 parts of water are added to the second reaction vessel and stirred evenly. 0.9 parts of ammonium persulfate and 20 parts of water are mixed evenly to prepare the oxidant solution for the first dropping device; 1 part of disodium 2-hydroxy-2-sulfoacetate, 2.5 parts of trisodium phosphate, and 20 parts of water are mixed evenly to prepare the chain transfer agent and reducing agent mixed solution for the second dropping device; 13 parts of acrylic acid, 8 parts of 2-methoxypropylene, and 20 parts of water are mixed evenly to prepare the acrylic acid and tert-butyl monomer mixed solution for the third dropping device.

[0100] The remaining operating steps are the same as in Example 1.

[0101] Example 4

[0102] This embodiment tests the effect of the coating dispersants prepared in Examples 1-3 and Comparative Examples 1-7.

[0103] 1. Dispersant performance testing

[0104] The dispersants for coatings synthesized in Examples 1-3 were compared with those in Comparative Examples 1-7 using Runfeng P.O42.5 cement, quartz sand with a fineness of 70-120 mesh, and heavy calcium carbonate with a fineness of 400 mesh. The dispersibility, dispersion retention, and powder-opening ability of the dispersants for coatings were tested. In the following tests, the powder ratio [cement: heavy calcium carbonate: quartz sand (70-120)] was 4:3:3, and the liquid-to-powder ratio was 1:1.9. By adjusting the amount of dispersant, the initial viscosity reached 90±5. The specific method is as follows:

[0105] Dispersibility test method: The emulsion, water and dispersant are dispersed in a disperser at 250 r / min for 2 min to prepare a liquid. After adding the powder according to the formula, the mixture is dispersed at 600-800 r / min for 5 min and then removed. The initial viscosity is tested using a Stormer viscometer and expressed as a KU value. The smaller the KU value, the better the dispersibility.

[0106] Dispersion retention test method: After the initial viscosity test, the mixture is placed in a container with a bag cap and left for 120 minutes. The viscosity of the mixture is then tested and the viscosity increase is compared. The result is expressed as ΔKU value. Within the same time period, the smaller the ΔKU value, the better the dispersion retention.

[0107] Powder-opening ability test method: The emulsion, water and dispersant are dispersed in a disperser at 250 r / min for 1 min to prepare a liquid material. After adding the powder according to the formula, the mixture is dispersed at 350 r / min for 3 min. The coating is then poured onto a glass plate and spread out using a wet film preparer. After standing for 1 day at 22℃, the number of particles in the dry film is observed. The fewer the particles, the better the powder-opening ability.

[0108] The results of the tests on the dispersibility, dispersion retention, and powder-opening ability of the dispersant are shown in Table 1.

[0109] Table 1. Test results of dispersibility, dispersion retention, and powder-opening ability of the dispersant.

[0110]

[0111] As shown in Table 1, the initial KU values ​​of each test group were all within the range of 90±3, indicating that the initial viscosity of each test group was the same. Compared with the comparative example, Examples 1-3 significantly reduced the dispersant dosage, indicating that the dispersant of the present invention can improve the early dispersion of pigments. In addition, the ΔKU values ​​and particle number of Examples 1-3 were significantly lower than those of the comparative example, further demonstrating that the product of the present invention can improve the viscosity retention of the coating system and reduce the agglomeration and accumulation of coating particles.

[0112] Compared to Example 1, Comparative Example 1 did not contain polyfluoroamide monomers, Comparative Example 2 replaced 3-tetrafluoroethoxyaniline with diethylenetriamine, and Comparative Example 3 replaced the polyfluoroamide monomer with trifluoroethyl methacrylate. All of these changes resulted in an increase in ΔKU value and particle number. This indicates that polyfluoroamide monomers prepared without 3-tetrafluoroethoxyaniline significantly reduce the viscosity stability of the coating and lead to more severe particle agglomeration and accumulation.

[0113] Compared with Example 1, Comparative Example 4 did not contain 1-(tert-butyldimethylsiloxy)-1-methoxyethylene, Comparative Example 5 replaced 1-(tert-butyldimethylsiloxy)-1-methoxyethylene with vinyltriethoxysilane, Comparative Example 6 replaced 1-(tert-butyldimethylsiloxy)-1-methoxyethylene with allyloxy-tert-butyldimethylsilane, and Comparative Example 7 replaced 1-(tert-butyldimethylsiloxy)-1-methoxyethylene with 2-methoxypropylene. All of these resulted in an increase in ΔKU value and particle number in Comparative Examples 4 to 7, indicating that the viscosity stability of the coating decreased and the particle agglomeration and accumulation phenomenon became more serious.

[0114] 2. Performance evaluation of dispersants on polymer cement waterproof coatings

[0115] The effect of dispersants on the tensile strength, bond strength and impermeability of polymer cement waterproof coatings was tested according to the standard GB / T 23445-2009 "Polymer Cement Waterproof Coatings". The test was conducted without any treatment, as shown in Table 2.

[0116] Table 2. Effects of dispersants on polymer cement waterproof coating performance.

[0117]

[0118]

[0119] As shown in Table 2, compared with the comparative example, the tensile strength, bond strength, and impermeability of Examples 1-3 were significantly higher than those of the comparative example. This indicates that the dispersant of the present invention can effectively improve the mechanical and waterproof properties of polymer cement waterproof coatings.

[0120] Compared with Example 1, no polyfluoroamide monomer was added in Comparative Example 1, while the key components of the polyfluoroamide monomer were replaced in Comparative Examples 2 and 3, resulting in a significant decrease in tensile strength, bond strength and impermeability.

[0121] Compared to Example 1, Comparative Example 4 lacked 1-(tert-butyldimethylsiloxy)-1-methoxyethylene, resulting in poorer tensile strength, bond strength, and impermeability of the polymer cement waterproof coating. While Comparative Examples 5-7, by replacing the monomers with other monomers (such as vinyltriethoxysilane, allyloxy-tert-butyldimethylsilane, and 2-methoxypropylene), showed some improvement in performance, it was still far inferior to the examples containing 1-(tert-butyldimethylsiloxy)-1-methoxyethylene. In conclusion, the silane monomer (1-(tert-butyldimethylsiloxy)-1-methoxyethylene) can improve the tensile strength, bond strength, and impermeability of polymer cement waterproof coatings.

[0122] 3. Surface tension assessment of dispersants

[0123] The dispersant was prepared into a 0.1% aqueous solution, and the surface tension of the solution was tested. The results are shown in Table 3.

[0124] Table 3 Surface tension of dispersants

[0125]

[0126]

[0127] As shown in Table 3, compared with the comparative examples, the surface tension of the coating systems in Examples 1 to 3 was significantly reduced. This indicates that the dispersant of the present invention can effectively reduce the surface tension of the coating, thereby significantly improving the fluidity and application performance of the coating.

[0128] Compared to Example 1, Comparative Examples 4-7 did not use or replaced 1-(tert-butyldimethylsiloxy)-1-methoxyethylene, resulting in a significant increase in their surface tension. This indicates that the introduction of 1-(tert-butyldimethylsiloxy)-1-methoxyethylene into the dispersant is key to achieving low surface tension and excellent wetting properties in the coating system.

[0129] In summary, based on their own experience and extensive research, the inventors have discovered that when using 1-(tert-butyldimethylsiloxy)-1-methoxyethylene, compared to not adding 1-(tert-butyldimethylsiloxy)-1-methoxyethylene or using other existing monomers that do not contain tert-butyl, methoxy, or siloxy groups, at lower dosages, the viscosity retention performance is better and the number of dry film particles is fewer. This demonstrates that the 1-(tert-butyldimethylsiloxy)-1-methoxyethylene in this invention has lower surface tension and better dispersion effect on particles in the coating system, effectively reducing the phenomenon of coating flocculation, agglomeration, and difficulty in dispersion; it can effectively improve the tensile strength, bond strength, and impermeability of polymer cement waterproof coatings.

[0130] The above results demonstrate that the polymeric dispersant for coatings provided by this invention, even at lower dosages, exhibits comparable initial viscosity, better viscosity retention, and fewer particles, effectively reducing the formation of undispersed flocculent particles in the coating. This is due to the synergistic effect of the raw materials in the dispersant, which allows the dispersant to maintain excellent dispersion and stability.

[0131] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0132] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A polymeric dispersant that can be used in coatings, characterized in that, The polymeric dispersant, by weight, comprises: 80-120 parts of ester macromonomers, 2-10 parts of polyfluoroamide monomers, 0.7-1.8 parts of emulsifiers, 0.5-3 parts of oxidants, 0.5-4 parts of reducing agents, 0.6-3 parts of chain transfer agents, 3-16 parts of acrylic acid, 3-10 parts of tert-butyl monomers, and 130-240 parts of water; The ester macromonomer is one of the following: polyethylene glycol monomethoxy ether monomethacrylate, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, and polyethylene glycol monomethacrylate, with a molecular weight of 1000-3000. The structural formula of the polyfluoroamide monomer is: or ; The tert-butyl monomer is 1-(tert-butyldimethylsiloxy)-1-methoxyethylene.

2. The polymeric dispersant as described in claim 1, characterized in that, The polymeric dispersant comprises, by weight: 100 parts ester macromonomer, 2-7 parts polyfluoroamide monomer, 0.9-1.5 parts emulsifier, 0.5-2.5 parts oxidant, 0.5-3 parts reducing agent, 0.8-2.5 parts chain transfer agent, 4-13 parts acrylic acid, 4-8 parts tert-butyl monomer, and 170-200 parts water.

3. The polymeric dispersant as described in claim 2, characterized in that, The polymeric dispersant, by weight, comprises: 100 parts ester macromonomer, 5 parts polyfluoroamide monomer, 1.35-1.5 parts emulsifier, 0.9-2.5 parts oxidant, 1-1.5 parts reducing agent, 1.3-2.5 parts chain transfer agent, 6-13 parts acrylic acid, 6.5-8 parts tert-butyl monomer, and 180-200 parts water.

4. The polymeric dispersant according to any one of claims 1 to 3, characterized in that, The polyfluoroamide monomer comprises, by weight: 100 parts unsaturated acid, 45-250 parts 3-tetrafluoroethoxyaniline, 1-9 parts catalyst, 1.5-3.5 parts polymerization inhibitor, and 70-100 parts organic solvent. Wherein, the unsaturated acid is one of acrylic acid and methacrylic acid; the catalyst is one of toluenesulfonic acid, concentrated sulfuric acid, aluminum trichloride, and phosphoric acid; the polymerization inhibitor is one of hydroquinone, 4-tert-butylcatechol, 2,6-di-tert-butyl-p-methylphenol, methylhydroquinone, 1,4-naphthoquinone, p-benzoquinone, and bisphenol A; and the organic solvent is carbon tetrachloride or diethyl ether.

5. The polymeric dispersant according to any one of claims 1 to 3, characterized in that: The emulsifier is composed of sodium dodecylbenzenesulfonate and diethylene glycol monolaurate in a mass ratio of 1:2; and / or; The oxidant is at least one selected from ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, and tert-butyl hydroperoxide; and / or; The reducing agent is at least one of sodium bisulfite, ascorbic acid, disodium 2-hydroxy-2-sulfoacetate, or glucose; and / or; The chain transfer agent is at least one of mercaptopropionic acid, mercaptoethanol, sodium formate, dithiobenzoic acid butyrate, mercaptopropionic acid, or trisodium phosphate.

6. A method for preparing a polymeric dispersant as described in any one of claims 1 to 5, characterized in that, The preparation method includes the following steps: pre-emulsifying ester macromonomers, polyfluoroamide monomers, emulsifiers, and water in a reaction vessel; then adding a portion of the oxidant solution, a portion of the chain transfer agent and reducing agent mixture, and a portion of the acrylic acid and tert-butyl monomer mixture into the reaction vessel; heating to 45-55℃ and reacting for 1-1.5 hours to obtain a seed emulsion; then simultaneously adding the remaining oxidant solution, chain transfer agent and reducing agent mixture, and acrylic acid and tert-butyl monomer mixture dropwise over 1-1.5 hours; maintaining the temperature for 30 minutes; and after the reaction is complete, adding 32% liquid alkali to adjust the pH to 6-7.

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