A method for preparing water-based environmentally friendly weather-resistant and water-resistant coating

Abstract

The invention relates to the technical field of waterproof coatings, and discloses a method for preparing a water-based environmentally friendly weather-resistant and water-resistant coating, comprising the following weight components: component A: 30-60 parts of polyurethane emulsion, 20-40 parts of zinc complex modified acrylate solution, 5-10 parts of film-forming aid, 1-5 parts of defoamer, component B: 10-20 parts of modified silicone polymer, 3-6 parts of colorant, 1-5 parts of leveling agent, 1-3 parts of thickener, 20-40 parts of water. The silicone polymer is modified with perfluorooctyl acrylate to effectively improve the weather resistance. The zinc complex polysiloxane prepolymer is prepared with zinc complex and siloxane, and then the acrylic resin is modified to greatly improve the water resistance and weather resistance. The water-based coating prepared by the invention has good water resistance and weather resistance, and the production process is green and environmentally friendly, and can be widely used in the fields of construction, machinery, and ships.

Description

Technical Field

[0001] The invention relates to the technical field of waterproof coatings, and in particular to a method for preparing a water-based, environmentally friendly, weather-resistant and water-resistant coating. Background Art

[0002] Although water-based paint has significant advantages in terms of environmental protection, its poor weather resistance and water resistance are more prominent in actual applications. In terms of weather resistance, the paint is exposed to the natural environment for a long time, and is affected by ultraviolet rays, temperature changes, humidity fluctuations and other factors, and the coating is prone to powdering, fading, cracking and other phenomena. This is because the molecular structure of the film-forming substances in water-based paint is prone to degradation and oxidation under ultraviolet rays, resulting in deterioration of coating performance. At the same time, drastic changes in temperature will cause thermal expansion and contraction stress in the coating, which will accelerate the destruction of the coating under repeated effects.

[0003] In terms of water resistance, water molecules can easily penetrate into the coating in a humid or water environment, reducing the adhesion between the coating and the substrate, causing blistering, shedding, etc. On the one hand, water-based coatings have certain hydrophilic groups after film formation, which are easy to interact with water; on the other hand, the microscopic pore structure inside the coating provides a channel for the penetration of water molecules.

[0004] Existing methods for improving the weather resistance and water resistance of water-based coatings have many limitations. For example, some methods improve the performance by adding a large amount of organic additives, but this not only increases the cost, but may also lead to an increase in VOC content, weakening the environmental advantages of water-based coatings. Some traditional modification methods, such as simple physical blending, can improve the performance to a certain extent, but the effect is limited and cannot fundamentally solve the durability problem of water-based coatings in complex environments.

[0005] In view of this, it is urgent to develop a preparation method that can fully utilize the environmental advantages of water-based coatings and significantly improve their weather resistance and water resistance. This is of great significance for expanding the application of water-based coatings in areas with high requirements for weather resistance and water resistance, such as building exterior walls, outdoor facilities, and marine engineering. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] In view of the deficiencies in the prior art, the present invention provides a method for preparing a water-based, environmentally friendly, weather-resistant and water-resistant coating.

[0008] (II) Technical solution

[0009] A method for preparing a water-based environmentally friendly weather-resistant and water-resistant coating comprises the following steps:

[0010] S1. Add dimethyldiethoxysilane and a silane coupling agent to an ethanol solution, then drop concentrated hydrochloric acid, react at 60-80°C for 3-6 hours, and remove the solvent by distillation under reduced pressure to obtain an organosilicon polymer;

[0011] S2, mixing the organosilicon polymer and toluene, stirring evenly, slowly adding perfluorooctyl acrylate, benzoyl peroxide and dibutyltin dilaurate, stirring for 10-30 min, heating to 80-90°C, reacting for 4-6 h, and removing the solvent by reduced pressure distillation to obtain a modified organosilicon polymer;

[0012] S3, adding zinc chloride trihydrate into water to prepare a zinc chloride solution, adjusting the pH to 1-2 with hydrochloric acid, slowly dripping the zinc chloride solution into a 60% by mass acrylic acid solution, and adjusting the pH to 4-6 to obtain a zinc acrylate complex;

[0013] S4, add diethanolamine to methanol, stir to dissolve, slowly dropwise add zinc acrylate complex, raise the temperature to 30-40°C, keep the temperature to react for 2-6 hours, and remove the solvent in vacuo to obtain terminal hydroxyl zinc acrylate complex;

[0014] S5, mixing the terminal hydroxyl acrylate zinc complex, γ-(methacryloyloxy)propyltrimethoxysilane, potassium hydroxide and dimethyl sulfoxide, passing nitrogen, stirring and heating to 80-90° C., reacting for 2-6 h, to obtain a zinc complex polysiloxane prepolymer;

[0015] S6, butyl acrylate, methyl acrylate, emulsifier Span-60, and deionized water were mixed, stirred for 30-60 min, initiator ammonium persulfate was added, the temperature was 70-80°C, zinc complex polysiloxane prepolymer was added dropwise, the reaction was kept warm for 2-5 h, and the pH was adjusted to neutral to obtain zinc complex modified acrylate solution;

[0016] S7. Mix the polyurethane emulsion, zinc complex modified acrylate solution, film-forming aid and defoaming agent, stir evenly to prepare component A; mix the modified silicone polymer, colorant, leveling agent, thickener and water to prepare component B; add component B to component A, disperse at a high speed of 800-1200 r / min for 10-30 min to obtain a water-based environmentally friendly weather-resistant and water-resistant coating.

[0017] Preferably, in step S1, the mass ratio of dimethyldiethoxysilane, silane coupling agent and concentrated hydrochloric acid is 1:0.8-1.2:0.005-0.01; the silane coupling agent is one of KH550, KH560, KH570 and KH590.

[0018] Preferably, in step S2, the mass ratio of the organosilicon polymer, toluene, perfluorooctyl acrylate, benzoyl peroxide, and dibutyltin dilaurate is 1:0.4-0.6:0.1-0.3:0.01-0.03:0.01-0.02.

[0019] Preferably, in step S3, the mass ratio of zinc chloride trihydrate to acrylic acid solution is 1:8-12.

[0020] Preferably, in step S4, the mass ratio of diethanolamine, methanol and zinc acrylate complex is 1:1.2~1.5:1.5~2.

[0021] Preferably, in step S5, the mass ratio of the terminal hydroxyl acrylate zinc complex, γ-(methacryloyloxy)propyltrimethoxysilane, potassium hydroxide and dimethyl sulfoxide is 90:5~15:1~3:1~3.

[0022] Preferably, in step S6, the mass ratio of butyl acrylate, methyl acrylate, emulsifier, deionized water, initiator ammonium persulfate, and zinc complex polysiloxane prepolymer is 1:0.8~1.2:0.03~0.06:4~6:0.05~0.08:0.2~0.5.

[0023] Preferably, the water-based environmentally friendly weather-resistant and water-resistant coating in step S7 includes the following components by weight: component A: 30-60 parts of polyurethane emulsion, 20-40 parts of zinc complex modified acrylate solution, 5-10 parts of film-forming aid, 1-5 parts of defoaming agent, component B: 10-20 parts of modified silicone polymer, 3-6 parts of colorant, 1-5 parts of leveling agent, 1-3 parts of thickener, 20-40 parts of water; the film-forming aid is one of dodecyl alcohol ester, propylene glycol methyl ether, and propylene glycol phenyl ether; the defoaming agent is BYK025; the colorant is titanium dioxide, carbon black, red iron oxide, benzidine yellow or phthalocyanine blue; the leveling agent is BYK346; the thickener is UH420.

[0024] 3. Beneficial technical effects

[0025] A water-based, environment-friendly, weather-resistant and water-resistant coating comprises the following components by weight: component A: 30-60 parts of polyurethane emulsion, 20-40 parts of zinc complex modified acrylate solution, 5-10 parts of film-forming aid, 1-5 parts of defoaming agent, component B: 10-20 parts of modified silicone polymer, 3-6 parts of colorant, 1-5 parts of leveling agent, 1-3 parts of thickener, and 20-40 parts of water.

[0026] The silicone polymer is modified with perfluorooctyl acrylate to effectively improve the weather resistance. The zinc complex polysiloxane prepolymer is prepared with zinc complex and siloxane, and then the acrylic resin is modified to greatly improve the water resistance and weather resistance.

[0027] The water-based paint prepared by the invention has good water and weather resistance, a green and environmentally friendly production process, and can be widely used in the fields of construction, machinery, ships, etc. DETAILED DESCRIPTION

[0028] Example 1

[0029] S1. Add 50 parts by weight of dimethyldiethoxysilane and 40 parts by weight of silane coupling agent KH550 to 200 parts by weight of ethanol solution, then drop 0.25 parts by weight of concentrated hydrochloric acid, react at 60° C. for 3 h, and remove the solvent by distillation under reduced pressure to obtain an organosilicon polymer.

[0030] S2. Mix 50 parts by weight of an organosilicon polymer and 20 parts by weight of toluene, stir evenly, slowly add 5 parts by weight of perfluorooctyl acrylate, 0.5 parts by weight of benzoyl peroxide and 0.5 parts by weight of dibutyltin dilaurate, stir for 10 min, heat to 80° C., react for 4 h, and remove the solvent by distillation under reduced pressure to obtain a modified organosilicon polymer.

[0031] S3. Add 20 parts by weight of zinc chloride trihydrate to 150 parts by weight of water to prepare a zinc chloride solution, adjust the pH to 1 with hydrochloric acid, slowly drop the zinc chloride solution into 160 parts by weight of an acrylic acid solution with a mass fraction of 60%, and adjust the pH to 4 to obtain a zinc acrylate complex.

[0032] S4. Add 30 parts by weight of diethanolamine to 36 parts by weight of methanol, stir to dissolve, slowly drop 45 parts by weight of zinc acrylate complex, raise the temperature to 30°C, keep the temperature for 2 hours, and remove the solvent in vacuo to obtain terminal hydroxyl zinc acrylate complex.

[0033] S5. Mix 45 parts by weight of terminal hydroxyl acrylate zinc complex, 2.5 parts by weight of γ-(methacryloyloxy)propyltrimethoxysilane, 0.5 parts by weight of potassium hydroxide, and 0.5 parts by weight of dimethyl sulfoxide, pass nitrogen, stir and heat to 80°C, react for 2 hours, and obtain zinc complex polysiloxane prepolymer.

[0034] S6. Mix 50 parts by weight of butyl acrylate, 40 parts by weight of methyl acrylate, 1.5 parts by weight of emulsifier Span-60, and 200 parts by weight of deionized water, stir for 30 min, add 2.5 parts by weight of initiator ammonium persulfate, add 10 parts by weight of zinc complex polysiloxane prepolymer dropwise at a temperature of 70°C, keep warm for reaction for 2 h, adjust the pH to neutral, and obtain a zinc complex modified acrylate solution.

[0035] S7. Mix 30 parts by weight of polyurethane emulsion, 20 parts by weight of zinc complex modified acrylate solution, 5 parts by weight of film-forming aid dodecanol ester, and 1 part by weight of defoamer BYK025, stir evenly to prepare component A; mix 10 parts by weight of modified silicone polymer, 3 parts by weight of colorant titanium dioxide, 1 part by weight of leveling agent BYK346, 1 part by weight of thickener UH420, and 20 parts by weight of water to prepare component B; add component B to component A, disperse at a high speed of 800 r / min for 10 min, and obtain a water-based, environmentally friendly, weather-resistant and water-resistant coating.

[0036] Example 2

[0037] S1. Add 50 parts by weight of dimethyldiethoxysilane and 60 parts by weight of silane coupling agent KH560 to 200 parts by weight of ethanol solution, then drop 0.5 parts by weight of concentrated hydrochloric acid, react at 80° C. for 6 h, and remove the solvent by reduced pressure distillation to obtain an organosilicon polymer.

[0038] S2. Mix 50 parts by weight of an organosilicon polymer and 30 parts by weight of toluene, stir evenly, slowly add 15 parts by weight of perfluorooctyl acrylate, 1.5 parts by weight of benzoyl peroxide and 1 part by weight of dibutyltin dilaurate, stir for 30 min, heat to 90° C., react for 6 h, and remove the solvent by distillation under reduced pressure to obtain a modified organosilicon polymer.

[0039] S3. Add 20 parts by weight of zinc chloride trihydrate to 150 parts by weight of water to prepare a zinc chloride solution, adjust the pH to 2 with hydrochloric acid, slowly drop the zinc chloride solution into 240 parts by weight of an acrylic acid solution with a mass fraction of 60%, and adjust the pH to 6 to obtain a zinc acrylate complex.

[0040] S4. Add 30 parts by weight of diethanolamine to 45 parts by weight of methanol, stir to dissolve, slowly drop 60 parts by weight of zinc acrylate complex, raise the temperature to 40°C, keep the temperature for 6 hours, and remove the solvent in vacuo to obtain terminal hydroxyl zinc acrylate complex.

[0041] S5. Mix 45 parts by weight of terminal hydroxyl acrylate zinc complex, 7.5 parts by weight of γ-(methacryloyloxy)propyltrimethoxysilane, 1.5 parts by weight of potassium hydroxide, and 1.5 parts by weight of dimethyl sulfoxide, pass nitrogen, stir and heat to 90°C, react for 6 hours, and obtain zinc complex polysiloxane prepolymer.

[0042] S6. Mix 50 parts by weight of butyl acrylate, 60 parts by weight of methyl acrylate, 3 parts by weight of emulsifier Span-60, and 300 parts by weight of deionized water, stir for 60 min, add 4 parts by weight of initiator ammonium persulfate, add 25 parts by weight of zinc complex polysiloxane prepolymer dropwise at a temperature of 80°C, keep warm for reaction for 5 h, adjust the pH to neutral, and obtain a zinc complex modified acrylate solution.

[0043] S7. Mix 60 parts by weight of polyurethane emulsion, 40 parts by weight of zinc complex modified acrylate solution, 10 parts by weight of film-forming aid propylene glycol methyl ether, and 5 parts by weight of defoamer BYK025, stir evenly to prepare component A; mix 20 parts by weight of modified silicone polymer, 6 parts by weight of colorant carbon black, 5 parts by weight of leveling agent BYK346, 3 parts by weight of thickener UH420, and 40 parts by weight of water to prepare component B; add component B to component A, disperse at a high speed of 1200 r / min for 30 min, and obtain a water-based, environmentally friendly, weather-resistant and water-resistant coating.

[0044] Example 3

[0045] S1. Add 50 parts by weight of dimethyldiethoxysilane and 42 parts by weight of silane coupling agent KH570 to 200 parts by weight of ethanol solution, then drop 0.3 parts by weight of concentrated hydrochloric acid, react at 80° C. for 4 h, and remove the solvent by reduced pressure distillation to obtain an organosilicon polymer.

[0046] S2. Mix 50 parts by weight of an organosilicon polymer and 25 parts by weight of toluene, stir evenly, slowly add 6 parts by weight of perfluorooctyl acrylate, 0.8 parts by weight of benzoyl peroxide and 0.6 parts by weight of dibutyltin dilaurate, stir for 15 min, heat to 90° C., react for 5 h, and remove the solvent by distillation under reduced pressure to obtain a modified organosilicon polymer.

[0047] S3. Add 20 parts by weight of zinc chloride trihydrate to 150 parts by weight of water to prepare a zinc chloride solution, adjust the pH to 2 with hydrochloric acid, slowly drop the zinc chloride solution into 18 parts by weight of an acrylic acid solution with a mass fraction of 60%, and adjust the pH to 5 to obtain a zinc acrylate complex.

[0048] S4. Add 30 parts by weight of diethanolamine to 40 parts by weight of methanol, stir to dissolve, slowly drop 50 parts by weight of zinc acrylate complex, raise the temperature to 35° C., keep the temperature for 3 h, and remove the solvent in vacuo to obtain a terminal hydroxyl zinc acrylate complex.

[0049] S5. Mix 45 parts by weight of terminal hydroxyl acrylate zinc complex, 3 parts by weight of γ-(methacryloyloxy)propyltrimethoxysilane, 0.8 parts by weight of potassium hydroxide, and 1 part by weight of dimethyl sulfoxide, pass nitrogen, stir and heat to 80°C, react for 5 hours, and obtain zinc complex polysiloxane prepolymer.

[0050] S6. Mix 50 parts by weight of butyl acrylate, 50 parts by weight of methyl acrylate, 2 parts by weight of emulsifier Span-60, and 220 parts by weight of deionized water, stir for 40 min, add 3 parts by weight of initiator ammonium persulfate, add 15 parts by weight of zinc complex polysiloxane prepolymer dropwise at a temperature of 80°C, keep warm for reaction for 3 h, adjust the pH to neutral, and obtain a zinc complex modified acrylate solution.

[0051] S7. Mix 40 parts by weight of polyurethane emulsion, 25 parts by weight of zinc complex modified acrylate solution, 6 parts by weight of film-forming aid propylene glycol phenyl ether, and 2 parts by weight of defoamer BYK025, stir evenly to prepare component A; mix 10 parts by weight of modified silicone polymer, 4 parts by weight of colorant red iron oxide, 2 parts by weight of leveling agent BYK346, 1 part by weight of thickener UH420, and 20 parts by weight of water to prepare component B; add component B to component A, disperse at a high speed of 1000 r / min for 20 min, and obtain a water-based, environmentally friendly, weather-resistant and water-resistant coating.

[0052] Example 4

[0053] S1. Add 50 parts by weight of dimethyldiethoxysilane and 45 parts by weight of silane coupling agent KH590 to 200 parts by weight of ethanol solution, then drop 0.4 parts by weight of concentrated hydrochloric acid, react at 70° C. for 5 h, and remove the solvent by distillation under reduced pressure to obtain an organosilicon polymer.

[0054] S2. Mix 50 parts by weight of an organosilicon polymer and 25 parts by weight of toluene, stir evenly, slowly add 10 parts by weight of perfluorooctyl acrylate, 1 part by weight of benzoyl peroxide and 0.8 parts by weight of dibutyltin dilaurate, stir for 20 min, heat to 80°C, react for 5 h, and remove the solvent by distillation under reduced pressure to obtain a modified organosilicon polymer.

[0055] S3. Add 20 parts by weight of zinc chloride trihydrate to 150 parts by weight of water to prepare a zinc chloride solution, adjust the pH to 2 with hydrochloric acid, slowly drop the zinc chloride solution into 200 parts by weight of an acrylic acid solution with a mass fraction of 60%, and adjust the pH to 5 to obtain a zinc acrylate complex.

[0056] S4. Add 30 parts by weight of diethanolamine to 38 parts by weight of methanol, stir to dissolve, slowly drop 55 parts by weight of zinc acrylate complex, raise the temperature to 40°C, keep the temperature for reaction for 5 hours, and remove the solvent in vacuo to obtain terminal hydroxyl zinc acrylate complex.

[0057] S5. Mix 45 parts by weight of terminal hydroxyl acrylate zinc complex, 4 parts by weight of γ-(methacryloyloxy)propyltrimethoxysilane, 1 part by weight of potassium hydroxide, and 1.2 parts by weight of dimethyl sulfoxide, pass nitrogen, stir and heat to 90°C, react for 5 hours, and obtain zinc complex polysiloxane prepolymer.

[0058] S6. Mix 50 parts by weight of butyl acrylate, 45 parts by weight of methyl acrylate, 2.5 parts by weight of emulsifier Span-60, and 250 parts by weight of deionized water, stir for 50 min, add 3.2 parts by weight of initiator ammonium persulfate, add 20 parts by weight of zinc complex polysiloxane prepolymer dropwise at a temperature of 70°C, keep warm for reaction for 2 h, adjust the pH to neutral, and obtain a zinc complex modified acrylate solution.

[0059] S7. Mix 50 parts by weight of polyurethane emulsion, 30 parts by weight of zinc complex modified acrylate solution, 9 parts by weight of film-forming aid dodecyl alcohol ester, and 4 parts by weight of defoamer BYK025, stir evenly to prepare component A; mix 15 parts by weight of modified silicone polymer, 4 parts by weight of colorant benzidine yellow, 1 part by weight of leveling agent BYK346, 2 parts by weight of thickener UH420, and 30 parts by weight of water to prepare component B; add component B to component A, disperse at a high speed of 900 r / min for 30 min, and obtain a water-based, environmentally friendly, weather-resistant and water-resistant coating.

[0060] Example 5

[0061] S1. Add 50 parts by weight of dimethyldiethoxysilane and 55 parts by weight of silane coupling agent KH550 to 200 parts by weight of ethanol solution, then drop 0.45 parts by weight of concentrated hydrochloric acid, react at 70° C. for 5 h, and remove the solvent by reduced pressure distillation to obtain an organosilicon polymer.

[0062] S2. Mix 50 parts by weight of an organosilicon polymer and 28 parts by weight of toluene, stir evenly, slowly add 14 parts by weight of perfluorooctyl acrylate, 1.3 parts by weight of benzoyl peroxide and 0.6 parts by weight of dibutyltin dilaurate, stir for 20 min, heat to 90° C., react for 5 h, and remove the solvent by distillation under reduced pressure to obtain a modified organosilicon polymer.

[0063] S3. Add 20 parts by weight of zinc chloride trihydrate to 150 parts by weight of water to prepare a zinc chloride solution, adjust the pH to 1 with hydrochloric acid, slowly drop the zinc chloride solution into 220 parts by weight of an acrylic acid solution with a mass fraction of 60%, and adjust the pH to 6 to obtain a zinc acrylate complex.

[0064] S4. Add 30 parts by weight of diethanolamine to 42 parts by weight of methanol, stir to dissolve, slowly drop 50 parts by weight of zinc acrylate complex, raise the temperature to 40°C, keep the temperature for reaction for 5 hours, and remove the solvent in vacuo to obtain terminal hydroxyl zinc acrylate complex.

[0065] S5. Mix 45 parts by weight of terminal hydroxyl acrylate zinc complex, 6 parts by weight of γ-(methacryloyloxy)propyltrimethoxysilane, 1.2 parts by weight of potassium hydroxide, and 1 part by weight of dimethyl sulfoxide, pass nitrogen, stir and heat to 90°C, react for 6 hours, and obtain zinc complex polysiloxane prepolymer.

[0066] S6. Mix 50 parts by weight of butyl acrylate, 60 parts by weight of methyl acrylate, 2 parts by weight of emulsifier Span-60, and 280 parts by weight of deionized water, stir for 50 min, add 3.6 parts by weight of initiator ammonium persulfate, add 22 parts by weight of zinc complex polysiloxane prepolymer dropwise at a temperature of 70°C, keep warm for reaction for 5 h, adjust the pH to neutral, and obtain a zinc complex modified acrylate solution.

[0067] S7. Mix 40 parts by weight of polyurethane emulsion, 30 parts by weight of zinc complex modified acrylate solution, 8 parts by weight of film-forming aid dodecanol ester, and 4 parts by weight of defoamer BYK025, stir evenly to prepare component A; mix 15 parts by weight of modified silicone polymer, 5 parts by weight of colorant phthalocyanine blue, 2 parts by weight of leveling agent BYK346, 3 parts by weight of thickener UH420, and 35 parts by weight of water to prepare component B; add component B to component A, disperse at a high speed of 1200 r / min for 30 min, and obtain a water-based, environmentally friendly, weather-resistant and water-resistant coating.

[0068] Comparative Example 1

[0069] 30 parts by weight of polyurethane emulsion, 5 parts by weight of film-forming aid dodecanol ester, and 1 part by weight of defoamer BYK025 were mixed and stirred evenly to prepare component A; 3 parts by weight of colorant titanium dioxide, 1 part by weight of leveling agent BYK346, 1 part by weight of thickener UH420, and 20 parts by weight of water were mixed to prepare component B; component B was added to component A, and dispersed at a high speed of 800 r / min for 10 minutes to obtain a water-based, environmentally friendly, weather-resistant and water-resistant coating.

[0070] Comparative Example 2

[0071] S1. Add 20 parts by weight of zinc chloride trihydrate to 150 parts by weight of water to prepare a zinc chloride solution, adjust the pH to 1 with hydrochloric acid, slowly drop the zinc chloride solution into 160 parts by weight of an acrylic acid solution with a mass fraction of 60%, and adjust the pH to 4 to obtain a zinc acrylate complex.

[0072] S2. Add 30 parts by weight of diethanolamine to 36 parts by weight of methanol, stir to dissolve, slowly drop 45 parts by weight of zinc acrylate complex, raise the temperature to 30°C, keep the temperature for 2 hours, and remove the solvent in vacuo to obtain a terminal hydroxyl zinc acrylate complex.

[0073] S3. Mix 45 parts by weight of terminal hydroxyl acrylate zinc complex, 2.5 parts by weight of γ-(methacryloyloxy)propyltrimethoxysilane, 0.5 parts by weight of potassium hydroxide, and 0.5 parts by weight of dimethyl sulfoxide, pass nitrogen, stir and heat to 80°C, react for 2 hours, and obtain zinc complex polysiloxane prepolymer.

[0074] S4. Mix 50 parts by weight of butyl acrylate, 40 parts by weight of methyl acrylate, 1.5 parts by weight of emulsifier Span-60, and 200 parts by weight of deionized water, stir for 30 min, add 2.5 parts by weight of initiator ammonium persulfate, add 10 parts by weight of zinc complex polysiloxane prepolymer dropwise at a temperature of 70°C, keep warm for reaction for 2 h, adjust the pH to neutral, and obtain a zinc complex modified acrylate solution.

[0075] S5. Mix 30 parts by weight of polyurethane emulsion, 20 parts by weight of zinc complex modified acrylate solution, 5 parts by weight of film-forming aid dodecanol ester, and 1 part by weight of defoamer BYK025, and stir evenly to prepare component A; mix 3 parts by weight of colorant titanium dioxide, 1 part by weight of leveling agent BYK346, 1 part by weight of thickener UH420, and 20 parts by weight of water to prepare component B; add component B to component A, and disperse at a high speed of 800 r / min for 10 min to obtain a water-based, environmentally friendly, weather-resistant and water-resistant coating.

[0076] Comparative Example 3

[0077] S1. Add 50 parts by weight of dimethyldiethoxysilane and 40 parts by weight of silane coupling agent KH550 to 200 parts by weight of ethanol solution, then drop 0.25 parts by weight of concentrated hydrochloric acid, react at 60° C. for 3 h, and remove the solvent by distillation under reduced pressure to obtain an organosilicon polymer.

[0078] S2. Mix 50 parts by weight of an organosilicon polymer and 20 parts by weight of toluene, stir evenly, slowly add 5 parts by weight of perfluorooctyl acrylate, 0.5 parts by weight of benzoyl peroxide and 0.5 parts by weight of dibutyltin dilaurate, stir for 10 min, heat to 80° C., react for 4 h, and remove the solvent by distillation under reduced pressure to obtain a modified organosilicon polymer.

[0079] S3. Mix 30 parts by weight of polyurethane emulsion, 5 parts by weight of film-forming aid dodecanol ester, and 1 part by weight of defoamer BYK025, stir evenly to prepare component A; mix 10 parts by weight of modified silicone polymer, 3 parts by weight of colorant titanium dioxide, 1 part by weight of leveling agent BYK346, 1 part by weight of thickener UH420, and 20 parts by weight of water to prepare component B; add component B to component A, disperse at a high speed of 800 r / min for 10 min, and obtain a water-based, environmentally friendly, weather-resistant and water-resistant coating.

[0080] Performance test: The products prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were tested for performance according to JG / T 375-2012 standard. The results are shown in Table 1:

[0081] Table 1

[0082]

[0083] It can be seen from Table 1 that the coatings prepared in Examples 1 to 5 have good weather resistance and water resistance, the water resistance of the coating prepared in Comparative Example 2 is better than that of Comparative Examples 1 and 3, and the weather resistance of the coating prepared in Comparative Example 3 is better than that of Comparative Examples 1 and 2.

[0084] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a water-based environmentally friendly weather-resistant and water-resistant coating, characterized in that: The following steps are involved: S1. Add dimethyldiethoxysilane and a silane coupling agent to an ethanol solution, then drop concentrated hydrochloric acid, react at 60-80°C for 3-6 hours, and remove the solvent by distillation under reduced pressure to obtain an organosilicon polymer; S2, mixing the organosilicon polymer and toluene, stirring evenly, slowly adding perfluorooctyl acrylate, benzoyl peroxide and dibutyltin dilaurate, stirring for 10-30 min, heating to 80-90°C, reacting for 4-6 h, and removing the solvent by reduced pressure distillation to obtain a modified organosilicon polymer; S3, adding zinc chloride trihydrate into water to prepare a zinc chloride solution, adjusting the pH to 1-2 with hydrochloric acid, slowly dripping the zinc chloride solution into a 60% by mass acrylic acid solution, and adjusting the pH to 4-6 to obtain a zinc acrylate complex; S4, add diethanolamine to methanol, stir to dissolve, slowly dropwise add zinc acrylate complex, raise the temperature to 30-40°C, keep the temperature to react for 2-6 hours, and remove the solvent in vacuo to obtain terminal hydroxyl zinc acrylate complex; S5, mixing the terminal hydroxyl acrylate zinc complex, γ-(methacryloyloxy)propyltrimethoxysilane, potassium hydroxide and dimethyl sulfoxide, passing nitrogen, stirring and heating to 80-90° C., reacting for 2-6 h, to obtain a zinc complex polysiloxane prepolymer; S6, butyl acrylate, methyl acrylate, emulsifier Span-60, and deionized water were mixed, stirred for 30-60 min, initiator ammonium persulfate was added, the temperature was 70-80°C, zinc complex polysiloxane prepolymer was added dropwise, the reaction was kept warm for 2-5 h, and the pH was adjusted to neutral to obtain zinc complex modified acrylate solution; S7, mixing the polyurethane emulsion, the zinc complex modified acrylate solution, the film-forming aid, and the defoaming agent, stirring evenly to prepare component A; The modified silicone polymer, colorant, leveling agent, thickener and water are mixed to prepare component B; component B is added to component A, and high-speed dispersion is carried out at 800-1200 r / min for 10-30 min to obtain a water-based environmentally friendly weather-resistant and water-resistant coating.

2. The method for preparing a water-based environmentally friendly weather-resistant and water-resistant coating according to claim 1, characterized in that: In the step S1, the mass ratio of dimethyldiethoxysilane, silane coupling agent and concentrated hydrochloric acid is 1:0.8-1.2:0.005-0.01; the silane coupling agent is one of KH550, KH560, KH570 and KH590.

3. The method for preparing a water-based environmentally friendly weather-resistant and water-resistant coating according to claim 1, characterized in that: In the step S2, the mass ratio of the organosilicon polymer, toluene, perfluorooctyl acrylate, benzoyl peroxide, and dibutyltin dilaurate is 1:0.4-0.6:0.1-0.3:0.01-0.03:0.01-0.

02.

4. The method for preparing a water-based environmentally friendly weather-resistant and water-resistant coating according to claim 1, characterized in that: In step S3, the mass ratio of zinc chloride trihydrate to acrylic acid solution is 1:8-12.

5. The method for preparing a water-based environmentally friendly weather-resistant and water-resistant coating according to claim 1, characterized in that: In the step S4, the mass ratio of diethanolamine, methanol and zinc acrylate complex is 1:1.2-1.5:1.5-2.

6. The method for preparing a water-based environmentally friendly weather-resistant and water-resistant coating according to claim 1, characterized in that: In the step S5, the mass ratio of the terminal hydroxyl acrylate zinc complex, γ-(methacryloyloxy)propyltrimethoxysilane, potassium hydroxide and dimethyl sulfoxide is 90:5-15:1-3:1-3.

7. The method for preparing a water-based environmentally friendly weather-resistant and water-resistant coating according to claim 1, characterized in that: In the step S6, the mass ratio of butyl acrylate, methyl acrylate, emulsifier, deionized water, initiator ammonium persulfate, and zinc complex polysiloxane prepolymer is 1:0.8~1.2:0.03~0.06:4~6:0.05~0.08:0.2~0.

5.

8. The method for preparing a water-based environmentally friendly weather-resistant and water-resistant coating according to claim 1, characterized in that: The water-based environmentally friendly weather-resistant and water-resistant coating in step S7 includes the following components by weight: component A: 30-60 parts of polyurethane emulsion, 20-40 parts of zinc complex modified acrylate solution, 5-10 parts of film-forming aid, 1-5 parts of defoaming agent, component B: 10-20 parts of modified silicone polymer, 3-6 parts of colorant, 1-5 parts of leveling agent, 1-3 parts of thickener, 20-40 parts of water; the film-forming aid is one of dodecyl alcohol ester, propylene glycol methyl ether, and propylene glycol phenyl ether; the defoaming agent is BYK025; the colorant is titanium dioxide, carbon black, iron oxide red, benzidine yellow or phthalocyanine blue; the leveling agent is BYK346; the thickener is UH420.

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