Polymeric dispersant capable of being used for coating and preparation method of polymeric dispersant

Abstract

The invention belongs to the technical field of building admixtures, and particularly relates to a polymeric dispersant capable of being used for coatings and a preparation method of the polymeric dispersant. The polymeric dispersant is prepared from the following components in parts by weight: 100 parts of ester macromonomers, 2 to 7 parts of polyfluoro amide monomers, 0.9 to 1.5 parts of an emulsifying agent, 0.5 to 2.5 parts of an oxidizing agent, 0.5 to 3 parts of a reducing agent, 0.8 to 2.5 parts of a chain transfer agent, 4 to 13 parts of acrylic acid, 4 to 8 parts of tertiary butyl monomers and 170 to 200 parts of water. The high-molecular dispersant prepared by the method shows excellent viscosity retentivity under the condition of relatively low mixing amount; the dispersion effect of particles in a coating system is remarkably improved, and the phenomenon that the coating is difficult to disperse due to flocculation and agglomeration accumulation is reduced. Meanwhile, the preparation process provided by the invention is simple to operate, mild in reaction condition, easy for large-scale production, safe, environment-friendly and pollution-free in production process.

Description

Technical Field

[0001] The invention relates to the technical field of building admixtures, and in particular to a polymer dispersant that can be used for coatings and a preparation method thereof. Background Art

[0002] Dispersants are a type of additive that plays a wide range of important roles in coatings. Most of the coatings exist in the form of a mixture of agglomerates and coagulations of primary particles. If these pigment particles of different sizes cannot be dispersed into finer particles or primary particles and become a stable dispersion system that no longer aggregates or flocculates, defects such as flocculation, precipitation, floating color, reduced gloss, and reduced tinting power and hiding power will occur. At the same time, the fillers in the coatings are generally selected from inorganic materials with larger particle sizes. Since the inorganic fillers with larger particle sizes have a small specific surface area and weak adsorption capacity, they are easier to disperse than fillers with small particle sizes. However, the internal pores of the coating formed by the large particle size fillers are larger, and harmful substances are easy to invade during use, thereby reducing the overall service life of the coating. Small particle size materials have stronger cohesion and are difficult to disperse, resulting in poor fluidity of the coating. Therefore, if more small molecule materials are needed to make the internal structure of the coating denser, dispersants with better dispersibility are needed. Dispersants with various functional group types and polymer chain structures have been developed. The dispersant wets and adsorbs on the particle surface through the hydrophobic group at one end, while the hydrophilic group at the other end combines with the solvent medium, thereby reducing the adhesion between the particles, preventing flocculation or aggregation, and allowing the paint filler to form a stable dispersed suspension. With the development of the coating industry, a variety of coating dispersants have also appeared in China. The dispersants used in common aqueous solutions mainly include polymer electrolyte dispersants and polycarboxylic acid and its derivative dispersants. In actual use, this type of dispersant is prone to viscosity increase and agglomeration problems due to insufficient dispersant effect. Some coating manufacturers prefer to use foreign products such as BYK, Lubrizol, DuPont and Dow.

[0003] Therefore, developing a polymer dispersant that can be used in coatings to increase coating construction performance, improve coating construction performance, and reduce particle agglomeration plays a vital role in promoting the promotion of coatings. Summary of the invention

[0004] Based on this, the purpose of the present invention is to provide a polymer dispersant that can be used for coatings and a preparation method thereof, which improves the dispersion effect and rate of existing coatings and prevents the occurrence of viscosity increase and coating particle aggregation problems.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention provides a polymer dispersant that can be used for coatings. The polymer dispersant comprises, 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] Furthermore, the polymer dispersant comprises, by weight: 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.

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

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

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

[0011] Furthermore, the emulsifier is composed of sodium dodecylbenzene sulfonate 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, 2-hydroxy-2-sulfonic acid acetic acid disodium salt or glucose.

[0014] Furthermore, the chain transfer agent is one of mercaptopropionic acid, mercaptoethanol, sodium formate, dithiobenzoate butyric acid, mercaptopropionic acid or trisodium phosphate.

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

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

[0017] In a second aspect of the present invention, a polyfluoroamide monomer is provided, and the structural formula of the polyfluoroamide monomer 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, an inhibitor, and an organic solvent into a reaction vessel equipped with a condensation reflux device and mixing them, adjusting the temperature to 75-95°C, performing a reduced pressure distillation reaction for 4-6 hours, and vacuuming to remove the organic solvent after the reaction is completed to obtain the polyfluoroamide monomer.

[0020] Furthermore, the composition comprises, by weight: 100 parts of unsaturated acid, 45-250 parts of 3-tetrafluoroethoxyaniline, 1-9 parts of catalyst, 1.5-3.5 parts of polymerization inhibitor, and 70-100 parts of organic solvent.

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

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

[0023] Furthermore, the polymerization inhibitor is one of hydroquinone, 4-tert-butylcatechol, 2,6-di-tert-butyl-p-methylphenol, methyl hydroquinone, 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 polymer dispersant that can be used for coatings, comprising the following steps: adding an ester macromonomer, a polyfluoroamide monomer, an emulsifier and water to a reaction container for pre-emulsification for 30 minutes, then respectively adding 1 / 4 of an oxidant solution, 1 / 4 of a chain transfer agent and a reducing agent mixed solution, and 1 / 4 of a mixed solution of acrylic acid and tert-butyl monomers to the reaction container, heating to 45-55°C for reaction for 1-1.5 hours to obtain a seed emulsion, then simultaneously dripping the remaining oxidant solution, the chain transfer agent and a reducing agent mixed solution, and the acrylic acid and tert-butyl monomer mixed solution, the dripping is completed within 1-1.5 hours, the reaction is carried out at a constant temperature for 30 minutes, and after the reaction is completed, 32% liquid alkali is added to adjust the pH to 6-7.

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

[0027] The beneficial effects of the present invention are:

[0028] 1) The present invention uses 3-tetrafluoroethoxyaniline and unsaturated acid to carry out amidation reaction to prepare a polyfluoroamide monomer, and participates in a copolymerization reaction to make the molecular structure contain multiple fluorine groups. The fluorine atom has a high negative charge, which enhances the adsorption capacity of the coating dispersant to the pigment, is conducive to improving the early dispersion of the pigment and improving the viscosity retention of the coating system, and effectively reduces the flocculated particles generated by the undispersed pigment. The amide group helps to improve the compatibility of the dispersant and the pigment by enhancing the interaction with the pigment surface, thereby improving the overall dispersion effect.

[0029] 2) The present invention introduces 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene, so that the molecular structure contains tert-butyl, siloxy bonds and methoxy groups. As a large hydrophobic group, the tert-butyl group can significantly increase the steric hindrance of the molecules inside the coating, prevent close accumulation between molecules, and improve the fluidity and dispersibility of the coating. The siloxy bonds containing tert-butyl groups have higher bond energy, increase the stability of the group, and at the same time have the effect of wetting and reducing the surface tension of the coating, thereby improving the fluidity and construction performance of the coating. The methoxy group helps to improve the compatibility of the dispersant and the coating by enhancing the interaction with the coating surface, thereby improving the overall dispersion effect. By introducing a dispersant containing 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene, the tensile strength, bonding strength and impermeability of the polymer cement waterproof coating can be effectively improved.

[0030] 3) The process of the present 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 DESCRIPTION

[0031] The preferred embodiment of the present invention will be described in detail below in conjunction with specific embodiments. It should be noted that the following specific embodiments are provided only for the purpose of illustration and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0032] The experimental methods used in the following specific examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following specific examples can be obtained from conventional commercial channels or prepared according to conventional methods in the art unless otherwise specified.

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

[0034]

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

[0036] Furthermore, the preparation method of the polyfluoroamide monomer includes the following reaction steps: adding unsaturated acid, 3-tetrafluoroethoxyaniline, catalyst, inhibitor, and organic solvent into a reaction container equipped with a condensation reflux device and mixing, adjusting the temperature to 75-95° C., performing reduced pressure distillation reaction for 4-6 hours, and vacuumizing to remove the organic solvent after the reaction is completed to obtain the polyfluoroamide monomer.

[0037] Wherein, the structure of the 3-tetrafluoroethoxyaniline is:

[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, methyl hydroquinone, 1,4-naphthoquinone, p-benzoquinone and bisphenol A.

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

[0043] On the basis of the above reaction, the inventors used diethylenetriamine, which also contains an amino group and has adsorption capacity for pigment particles, as a substitute for 3-tetrafluoroethoxyaniline. However, through testing, it was found that after using diethylenetriamine to replace 3-tetrafluoroethoxyaniline to prepare polyfluoroamide monomers, the stability and dispersibility of the coating decreased, that is, the coating showed more serious particle agglomeration and accumulation. That is, 3-tetrafluoroethoxyaniline has an irreplaceable effect in the process of preparing polyfluoroamide monomers.

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

[0045] One of the embodiments of the present invention relates to a polymer dispersant that can be used for coatings. Taking 100 parts of ester macromonomer as an example, the polymer dispersant includes: 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 150-200 parts of water.

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

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

[0048] The emulsifier is composed of sodium dodecylbenzene sulfonate 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, 2-hydroxy-2-sulfonic acid acetic acid disodium salt or glucose.

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

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

[0053] The inventors have found through research that 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene contains structures of tert-butyl, methoxy and siloxy groups at the same time, and these characteristic groups produce unexpected synergistic effects with other raw materials. This effect significantly improves the dispersion performance of particles in the coating system and effectively reduces the phenomenon of coating flocculation, agglomeration and accumulation that makes it difficult to disperse.

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

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

[0056] In some embodiments of the present invention, a method for preparing a polymer dispersant that can be used for coatings is involved, and the method comprises the following steps: adding ester macromonomers, polyfluoroamide monomers, acyl chloride monomers, emulsifiers and water to a reaction vessel for pre-emulsification for 30 minutes, and then adding 1 / 4 of an oxidant solution, 1 / 4 of a chain transfer agent and a reducing agent mixed solution, and 1 / 4 of an acrylic acid and tert-butyl monomer mixed solution to the reaction vessel respectively, heating to 50°C for reaction for 1 hour to obtain a seed emulsion, and then dripping the remaining oxidant solution, chain transfer agent and reducing agent mixed solution, acrylic acid and tert-butyl monomer mixed solution at the same time, dripping in 120-200 minutes, reacting at a constant temperature for a period of time, and after the reaction is completed, adding 32% liquid alkali to adjust the pH to 6-7. That is, a polymer dispersant that can be used for coatings is obtained.

[0057] The following is a description with reference to specific embodiments.

[0058] Example 1

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

[0060] (1) Preparation of polyfluoroamide monomer: 100 parts by weight 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 into a first reaction container equipped with a condensation reflux device and mixed, and the temperature was adjusted to 85° C. and the reaction was carried out by reduced pressure distillation for 5 hours. After the reaction was completed, the organic solvent was removed by vacuum to obtain the polyfluoroamide monomer.

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

[0062] After adding the raw materials to the second reaction container, pre-emulsify for 30 minutes, then add 1 / 4 mass fraction of oxidant solution, 1 / 4 mass fraction of chain transfer agent and reducing agent mixed solution, 1 / 4 mass fraction of acrylic acid and tert-butyl monomer mixed solution to the second reaction container, heat to 50°C and react for 1 hour to obtain seed emulsion. At the same time, add the remaining oxidant solution, chain transfer agent and reducing agent mixed solution, acrylic acid and tert-butyl monomer mixed solution dropwise, drip it in 1.5 hours, react at constant temperature for 30 minutes, add 10 parts by weight of 32% mass concentration of sodium hydroxide after the reaction is completed, and adjust the pH to 6-7. That is, the polymer dispersant with a concentration of 40% that can be used for coatings is obtained.

[0063] Example 2

[0064] This embodiment provides a polymer dispersant that can be used for coatings and a preparation method thereof, including a polyfluoroamide monomer and a formulation and preparation method of a dispersant for coatings. The following is 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 of 3-tetrafluoroethoxyaniline, 1 part of concentrated sulfuric acid, 1.6 parts of 4-tert-butylcatechol and 78.52 parts of carbon tetrachloride were added into a first reaction container equipped with a condensation reflux device, and the mixture was mixed. The temperature was adjusted to 95° C. and the reaction was carried out by reduced pressure distillation for 6 hours. After the reaction was completed, the organic solvent was removed by vacuum to obtain the polyfluoroamide monomer.

[0066] (2) Dispersant for coating: 100 parts by weight of polyethylene glycol monoacrylate with a molecular weight of 3000, 5 parts of the polyfluoroamide monomer obtained in step (1), 0.45 parts of sodium dodecylbenzene sulfonate, 0.9 parts of diethylene glycol monolaurate and 124 parts of water are added to the second reaction container and stirred evenly. 2.3 parts of hydrogen peroxide and 20 parts of water are mixed evenly to prepare an 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 a chain transfer agent and reducing agent mixed solution for the second dropping device; 6 parts of acrylic acid, 6.5 parts of 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene and 20 parts of water are mixed evenly to prepare a mixed solution of acrylic acid and tert-butyl monomer for the third dropping device.

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

[0068] Example 3

[0069] This embodiment provides a polymer dispersant that can be used for coatings and a preparation method thereof, including a polyfluoroamide monomer and a formulation and preparation method of a dispersant for coatings. The following is 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 of 3-tetrafluoroethoxyaniline, 8.6 parts of p-toluenesulfonic acid, 3.1 parts of p-benzoquinone and 85.73 parts of carbon tetrachloride were added into a first reaction vessel equipped with a condensation reflux device and mixed, and the temperature was adjusted to 75° C. and the reaction was carried out by reduced pressure distillation for 4 hours. After the reaction was completed, the organic solvent was removed by vacuum to obtain the polyfluoroamide monomer.

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

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

[0073] Comparative Example 1

[0074] This comparative example provides a polymer dispersant that can be used for coatings. Compared with Example 1, the dispersant has the same components as Example 1 except that the polyfluoroamide monomer is not added.

[0075] Specifically, by weight, 100 parts of monomethoxy ether monomethacrylate polyethylene glycol ester with a molecular weight of 1000, 0.5 parts of sodium dodecylbenzene sulfonate, 1 part of diethylene glycol monolaurate and 133 parts of water are added to the second reaction container and stirred evenly. 0.9 parts of ammonium persulfate and 20 parts of water are mixed evenly to prepare an oxidant solution of the first dropping device; 1 part of 2-hydroxy-2-sulfonic acid acetic acid disodium salt, 2.5 parts of trisodium phosphate and 20 parts of water are mixed evenly to prepare a chain transfer agent and reducing agent mixed solution of the second dropping device; 13 parts of acrylic acid, 8 parts of 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene and 20 parts of water are mixed evenly to prepare a mixed solution of acrylic acid and tert-butyl monomer of the third dropping device.

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

[0077] Comparative Example 2

[0078] This comparative example provides a polymer dispersant that can be used for coatings. When preparing the polyfluoroamide monomer, compared with Example 1, except that the equimolar amount of 3-tetrafluoroethoxyaniline is replaced by diethylenetriamine, everything else is the same.

[0079] Specifically, the preparation method of the polyfluoroamide monomer is as follows, based on parts by weight: 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 container equipped with a condensation reflux device and mixed, and the temperature is adjusted to 85° C., and the reduced pressure distillation reaction is carried out for 5 hours. After the reaction is completed, the organic solvent is removed by vacuum to obtain the polyfluoroamide monomer.

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

[0081] Comparative Example 3

[0082] This comparative example provides a polymer dispersant that can be used for coatings. When preparing the dispersant, the polyfluoroamide monomer is replaced with trifluoroethyl methacrylate compared with Example 1, and the rest is the same.

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

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

[0085] Comparative Example 4

[0086] This comparative example provides a polymer dispersant that can be used for coatings. The dispersant is the same as Example 1 except that 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene is not added.

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

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

[0089] Comparative Example 5

[0090] This comparative example provides a polymer dispersant that can be used for coatings. When preparing the dispersant, compared with Example 1, except that 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene is replaced by vinyltriethoxysilane, all other aspects are the same.

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

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

[0093] Comparative Example 6

[0094] This comparative example provides a polymer dispersant that can be used for coatings. When preparing the dispersant, compared with Example 1, except that 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene is replaced by allyloxy-tert-butyldimethylsilane, all other aspects are the same.

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

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

[0097] Comparative Example 7

[0098] This comparative example provides a polymer dispersant that can be used for coatings. When preparing the dispersant, compared with Example 1, except that 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene is replaced by 2-methoxypropylene, everything else is the same.

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

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

[0101] Example 4

[0102] This example tests the effects of the coating dispersants prepared in Examples 1 to 3 and Comparative Examples 1 to 7.

[0103] 1. Dispersant performance test

[0104] The coating dispersants synthesized in Examples 1 to 3 and Comparative Examples 1 to 7 were tested for dispersibility, dispersion retention and powdering ability of the coating dispersants 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. In the following test, the powder [cement: heavy calcium carbonate: quartz sand (70-120)] = 4:3:3, the liquid-powder ratio was 1:1.9, and the initial viscosity reached 90±5 by adjusting the dispersant dosage. The specific method is as follows:

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

[0106] Dispersion retention test method: Place the mixture after the initial viscosity test in a container with a bag cover. After leaving it for 120 minutes, test the viscosity of the mixture and compare the viscosity increase. The ΔKU value is used to represent it. Within the same time period, the smaller the ΔKU value, the better the dispersion retention.

[0107] Powder-opening ability test method: Emulsion, water and dispersant are dispersed in a disperser at 250r / min for 1 minute to prepare a liquid material. After adding powder according to the formula, disperse it at 350r / min for 3 minutes, pour the paint on a glass plate and spread it flat with a wet film preparation device. Under 22°C environmental conditions, after leaving it for 1 day, observe the number of particles in the dry film. The fewer the particles, the better the powder-opening ability.

[0108] The test results of 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 dispersants

[0110]

[0111] As shown in Table 1, the initial KU values ​​of each test group are within the range of 90±3, indicating that the initial viscosity of each test group is the same. Compared with the comparative example, Examples 1 to 3 can significantly reduce the amount of dispersant, indicating that the dispersant of the present invention can improve the early dispersion of pigments. In addition, the ΔKU values ​​and particle numbers of Examples 1 to 3 are significantly lower than those of the comparative example, further indicating 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 with Example 1, Comparative Example 1 does not contain polyfluoroamide monomer, Comparative Example 2 replaces 3-tetrafluoroethoxyaniline with diethylenetriamine, and Comparative Example 3 replaces polyfluoroamide monomer with trifluoroethyl methacrylate, all of which lead to an increase in ΔKU value and an increase in the number of particles. This indicates that the polyfluoroamide monomer prepared without 3-tetrafluoroethoxyaniline will significantly reduce the viscosity stability of the coating and cause more serious particle agglomeration and accumulation.

[0113] Compared with Example 1, Comparative Example 4 does not contain 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene, Comparative Example 5 replaces 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene with vinyltriethoxysilane, Comparative Example 6 replaces 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene with allyloxy-tert-butyldimethylsilane, and Comparative Example 7 replaces 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene with 2-methoxypropylene, all of which lead to an increase in the ΔKU value and the number of particles in Comparative Examples 4 to 7, indicating that the viscosity stability of the coating is reduced, and the particle agglomeration and accumulation phenomenon are more serious.

[0114] 2. Evaluation of dispersant performance on polymer cement waterproof coating

[0115] The influence of dispersant on the tensile strength, bonding strength and impermeability of polymer cement waterproof coating was tested with reference to standard GB / T 23445-2009 "Polymer cement waterproof coating" using no treatment method, as shown in Table 2.

[0116] Table 2 Effect of dispersant on the performance of polymer cement waterproof coating

[0117]

[0118]

[0119] As shown in Table 2, compared with the comparative example, the tensile strength, bonding strength and impermeability of Examples 1 to 3 are significantly higher than those of the comparative example, indicating that the dispersant of the present invention can effectively improve the mechanical properties and waterproof properties of the polymer cement waterproof coating.

[0120] Compared with Example 1, Comparative Example 1 did not add the polyfluoroamide monomer, while Comparative Examples 2-3 replaced the key component of the polyfluoroamide monomer, resulting in a significant decrease in tensile strength, bonding strength and anti-permeability performance.

[0121] Compared with Example 1, Comparative Example 4 does not contain 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene, resulting in poor tensile strength, bonding strength and impermeability of the polymer cement waterproof coating; while Comparative Examples 5 to 7 are replaced with other monomers (such as vinyl triethoxysilane, allyloxy-tert-butyldimethylsilane, 2-methoxypropylene), although the performance is improved, it is far inferior to the embodiment containing 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene. In summary, the silane monomer (1-(tert-butyldimethylsilyloxy)-1-methoxyethylene) can improve the tensile strength, bonding strength and impermeability of the polymer cement waterproof coating.

[0122] 3. Evaluation of surface tension 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 example, the surface tension of the coating system of Examples 1 to 3 is significantly reduced, which shows that the dispersant of the present invention can effectively reduce the surface tension of the coating, thereby significantly improving the fluidity and construction performance of the coating.

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

[0129] In summary, the inventors have found, based on their own experience and extensive research, that when 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene is used, compared with not adding 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene or using other existing monomers that do not contain tert-butyl, methoxy or siloxy groups, at a lower dosage, the viscosity retention performance is better and the number of dry film particles is less. This shows that the 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene in the present invention has a lower surface tension and better dispersion effect on the particles in the coating system, and effectively reduces the phenomenon of coating flocculation, agglomeration and accumulation that are difficult to disperse; it can effectively improve the tensile strength, bonding strength and impermeability of the polymer cement waterproof coating.

[0130] The above results show that the polymer dispersant for coatings provided by the present invention has a comparable initial viscosity, better viscosity retention, and fewer particles at a lower dosage, and can effectively reduce flocculated particles generated by undispersed coatings. This is because the raw materials in the dispersant of the present invention cooperate with each other and complement each other, so that the dispersant can maintain excellent dispersion and stability.

[0131] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, 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 above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A polymer dispersant that can be used for coatings, characterized in that: The polymer dispersant comprises, 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.

2. The polymer dispersant according to claim 1, characterized in that The polymer dispersant comprises, by weight, 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.

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

4. The polymer dispersant according to any one of claims 1 to 3, characterized in that The structural formula of the polyfluoroamide monomer is as follows: Where m=0 or 1.

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

6. The polymer dispersant according to any one of claims 1 to 3, characterized in that The ester macromonomer is one of monomethoxy ether monomethacrylate polyethylene glycol ester, monoacrylate polyethylene glycol ester, monomethoxy ether monoacrylate polyethylene glycol ester and monomethacrylate polyethylene glycol ester with a molecular weight of 1000-3000.

7. The polymer dispersant according to any one of claims 1 to 3, characterized in that The tert-butyl monomer is 1-(tert-butyldimethylsilyloxy)-1-methoxyethylene.

8. The polymer dispersant according to any one of claims 1 to 3, characterized in that: The emulsifier is composed of sodium dodecylbenzene sulfonate and diethylene glycol monolaurate in a mass ratio of 1:2; and / or; The oxidant is at least one of 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, 2-hydroxy-2-sulfonic acid acetic acid disodium salt or glucose; and / or; The chain transfer agent is at least one of mercaptopropionic acid, mercaptoethanol, sodium formate, dithiobenzoate butyric acid, mercaptopropionic acid or trisodium phosphate.

9. A method for preparing a polyfluoroamide monomer, characterized in that: The preparation method comprises the following steps: adding unsaturated acid, 3-tetrafluoroethoxyaniline, catalyst, polymerization inhibitor and organic solvent into a reaction container equipped with a condensation reflux device, mixing, adjusting the temperature to 75-95° C., performing reduced pressure distillation reaction for 4-6 hours, and vacuumizing to remove the organic solvent after the reaction is completed, thereby obtaining the polyfluoroamide monomer.

10. A method for preparing a polymer dispersant according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: adding an ester macromonomer, a polyfluoroamide monomer, an emulsifier and water into a reaction container for pre-emulsification, respectively adding a portion of an oxidant solution, a portion of a chain transfer agent and a reducing agent mixed solution, and a portion of an acrylic acid and a tert-butyl monomer mixed solution into the reaction container, heating the reaction container to 45-55° C. for 1-1.5 hours to obtain a seed emulsion, then simultaneously dripping the remaining oxidant solution, the chain transfer agent and a reducing agent mixed solution, and the acrylic acid and a tert-butyl monomer mixed solution, the dripping is completed within 1-1.5 hours, the reaction is carried out at a constant temperature for 30 minutes, and after the reaction is completed, 32% liquid alkali is added to adjust the pH to 6-7.

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