Waterproof building coating and preparation method thereof

Abstract

The invention discloses a waterproof building coating and a preparation method thereof. The waterproof building coating is prepared from the following components in parts by weight: 25 to 30 parts of composite emulsion, 40 to 45 parts of vinyl acetate-ethylene copolymer emulsion, 0.2 to 0.4 part of dispersing agent, 0.4 to 0.6 part of defoaming agent, 1 to 2 parts of coalescing agent, 55 to 60 parts of sulphoaluminate cement, 25 to 30 parts of superfine talcum powder and 3 to 5 parts of fumed silica. The composite emulsion is prepared by compounding a nano-hydroxyapatite dispersion liquid, a semi-interpenetrating network polymer and a fluorine-modified copolymer, wherein the semi-interpenetrating network polymer contains a POSS cage structure and a polycaprolactone chain segment, and fluorine is introduced into the fluorine-modified copolymer. The inorganic filler and the organic base material have a synergistic effect, so that the compactness, the mechanical strength and the cohesiveness of the coating are improved. The coating is free of volatile toxic substances, mild in preparation process and low in energy consumption, has excellent weather resistance, waterproofness and self-healing capacity, can adapt to complex scenes such as a wet base layer and long-term soaking, solves the problem that a traditional coating is prone to cracking and delaminating, and is suitable for various building waterproof projects.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of architectural coatings, in particular to a waterproof architectural coating and a preparation method thereof. BACKGROUND

[0002] Building waterproofing is the core link to protect the structural safety and functional use of buildings, directly affecting the service life and living experience of buildings. With the acceleration of urbanization, complex building structures such as high-rise buildings and underground spaces are increasing, which puts higher requirements on the weather resistance, adhesion strength and long-term waterproofing performance of waterproof coatings. The current mainstream waterproof architectural coatings on the market are mostly based on single emulsion, which can meet the basic waterproofing needs, but in extreme environments, they are prone to cracking, delamination and other problems, especially in wet substrates or long-term immersion scenarios, the risk of waterproofing failure is significantly increased, making it difficult to adapt to the diversified waterproofing needs of modern buildings.

[0003] In the prior art, vinyl acetate-ethylene copolymer emulsion-based coatings are widely used due to their low cost, but they have inherent shortcomings in water resistance and mechanical properties; fluorocarbon coatings have excellent waterproofing performance, but their high cost limits their large-scale promotion. Some improved coatings add inorganic fillers to improve performance, but the poor compatibility between organic binders and inorganic fillers leads to insufficient uniformity of the coating, which in turn reduces the waterproofing effect. In addition, the preparation process of traditional coatings often involves complicated steps and high energy consumption, which is contrary to the development concept of green buildings, and there is an urgent need to develop a new type of waterproof architectural coating with balanced performance, controllable cost and environmental protection.

[0004] Based on the development of composite modification technology, the use of organic emulsion compounding and inorganic filler synergistic modification has become an effective way to improve the comprehensive performance of waterproof coatings. By utilizing the complementary effects of different emulsions and the reinforcing effect of specific functional fillers, the waterproofing, adhesion and weather resistance of the coating can be simultaneously improved. Based on this background, the present application develops a waterproof architectural coating that uses a composite emulsion as the core and specific inorganic fillers in a certain ratio to solve the problem of single performance and poor adaptability of existing products, providing a more reliable technical solution for building waterproofing projects. SUMMARY

[0005] The present application provides a waterproof architectural coating and a preparation method thereof. The coating contains a polymer containing a semi-interpenetrating network, which greatly improves the adhesion strength of the coating and the substrate, solves the delamination problem of traditional coatings, and endows the coating with waterproofing function.

[0006] Technical solution: A waterproof architectural coating, the coating contains the following components by weight fraction: Composite emulsion 25-30 parts Vinyl acetate-ethylene copolymer emulsion 40-45 parts Dispersant 0.2-0.4 parts Defoaming agent 0.4-0.6 parts Film forming aid 1-2 parts Sulphoaluminate cement 55-60 parts Superfine talc 25-30 parts Fumed silica 3-5 parts Preferably, the dispersant is sodium polycarboxylate, the defoaming agent is a silicone-based defoaming agent, specifically polydimethylsiloxane, the film forming aid is propylene glycol methyl ether acetate, and the superfine talc has a mesh size of 1000-1300 mesh.

[0007] Preferably, the preparation method of the composite emulsion comprises the following steps: S1. Ultrasonic dispersion of nano-hydroxyapatite in deionized water, solid-liquid ratio of nano-hydroxyapatite to deionized water 1:8-12, 5-8wt% of emulsifier SDBS added to the mass of nano-hydroxyapatite, and mixed solution obtained by stirring; S2. To the solution obtained in S1, semi-interpenetrating polymer and fluorine-modified copolymer with a mass ratio of 1:1-2 are added in turn, stirred at 30-40℃ for 20-50min, and the composite emulsion is prepared.

[0008] Preferably, the preparation of the semi-interpenetrating polymer in S2 comprises the following steps: S11. After melting polycaprolactone at 70-80℃, add toluene diisocyanate, the molar ratio of polycaprolactone to toluene diisocyanate is 1:2-4, then stir under nitrogen protection for 1-2h to obtain isocyanate-terminated polycaprolactone prepolymer; S12. Dissolve POSS methylacryloylpropyl cyclosiloxane and hydroxymethyl acrylamide with a mass ratio of 1:0.8-1 in N,N-dimethylformamide to obtain a solution with a mass fraction of 10-15wt%, heat to 70-80℃, add isocyanate-terminated polycaprolactone prepolymer, and stir for 3-4h; S13. Add initiator to the reaction system obtained in S2, continue to react for 2-3h to obtain semi-interpenetrating polymer.

[0009] Preferably, the preparation method of the fluorine-modified acrylate copolymer comprises the following steps: S21. Add mixed emulsifier solution and sodium bicarbonate aqueous solution with a mass ratio of 1:2-5:20-30 to water, then pass nitrogen gas under stirring conditions, and add DFMA, BA, MMA with a mass ratio of 1:2-3:1-2:0.4-0.8, continue to stir for 15-35min to obtain an emulsion; S22. The emulsion liquid obtained in S21 is warmed to 70-80℃, and an ammonium persulfate aqueous solution with a mass fraction of 4-8wt% is added dropwise, followed by reaction for 1-2h to obtain a seed emulsion; S23. DFMA, BA, MMA, HEA with a mass ratio of 1:2-3:1-2:0.4-0.8 are continuously added to the seed emulsion obtained in S22, followed by addition of an ammonium persulfate aqueous solution with a mass fraction of 4-8wt%, and reaction for 1.5-2h to obtain a fluorine-modified acrylate copolymer emulsion.

[0010] Preferably, the initiator in S13 is any one of azobisisobutyronitrile or benzoyl peroxide.

[0011] Preferably, the mixed emulsifier in S21 contains sodium dodecyl sulfate, OP-10 and water with a mass ratio of 1:2-8:25-35.

[0012] Beneficial effects: The present application has the following advantages: 1. The composite emulsion is compounded with a vinyl acetate-ethylene copolymer emulsion: the cage structure of POSS in the semi-interpenetrating network polymer provides rigid support, limits chain segment slipping, and improves the hardness and weather resistance of the coating; the crystallization-melting transition of the polycaprolactone segment endows the coating with elasticity and micro-crack self-healing ability; the fluorine-modified copolymer introduces fluorine elements, reduces the surface energy of the coating, and enhances the hydrophobic and waterproof performance; 2. In the present application, inorganic fillers are combined with organic binders: superfine talc can fill the internal voids of the coating and improve the compactness; fumed silica forms a three-dimensional network structure, enhancing the mechanical strength and crack resistance of the coating; the crosslinking reaction between the sulphoaluminate cement and the emulsion components greatly improves the bonding strength of the coating to the base layer, solving the problem of delamination of traditional coatings; 3. The formula provided by the present application does not contain volatile toxic and harmful substances, and the dispersants, defoamers and other additives are all environmentally friendly products, in line with the green building development concept; the preparation of the composite emulsion uses mild processes such as ultrasonic dispersion and low-temperature stirring, without the need for high-temperature and high-pressure equipment, and with lower energy consumption. DETAILED DESCRIPTION

[0013] The present application will be further described below in conjunction with examples, which are illustrative of the present application but not limiting the present application to the following examples: Example 1

[0014] A waterproof building coating, which contains the following components in parts by weight: Composite emulsion 25 parts Vinyl acetate-ethylene copolymer emulsion 40 parts Dispersant (sodium polycarboxylate) 0.2 parts Defoamer (polydimethylsiloxane) 0.4 parts 1 part of film-forming aid (propylene glycol methyl ether acetate) 55 parts of sulfoaluminate cement 25 parts of ultrafine talc powder (1000 mesh) 3 parts of fumed silica The method for preparing the composite emulsion includes the following steps: S1. Disperse nano-hydroxyapatite in deionized water using ultrasonication, with a solid-liquid ratio of nano-hydroxyapatite to deionized water of 1:8. Add 5 wt% of emulsifier SDBS based on the mass of nano-hydroxyapatite and stir to obtain a mixed solution. S2. Add a semi-interpenetrating network polymer and a fluorinated modified copolymer in a mass ratio of 1:1 to the solution obtained in S1, and stir at 30°C for 20 min to obtain a composite emulsion.

[0015] The preparation of the semi-interpenetrating network polymer in S2 includes the following steps: S11. Polycaprolactone was melted at 70°C and then toluene diisocyanate was added. The molar ratio of polycaprolactone to toluene diisocyanate was 1:2. The mixture was then stirred and reacted for 1 hour under nitrogen protection to obtain isocyanate-terminated polycaprolactone prepolymer. S12. POSS methacryloyloxypropylcyclotetrasiloxane and hydroxymethacrylamide in a mass ratio of 1:0.8 were added to N,N-dimethylformamide and dissolved to obtain a 10wt% solution. The solution was heated to 70℃, and isocyanate-terminated polycaprolactone prepolymer was added. The mixture was stirred and reacted for 3 hours. S13. Add an initiator (azobisisobutyronitrile or benzoyl peroxide) to the reaction system obtained from S2, and continue the reaction for 2 hours to obtain a semi-interpenetrating network polymer.

[0016] The preparation method of the fluorinated modified acrylate copolymer includes the following steps: S21. Add a mixed emulsifier solution (containing sodium dodecyl sulfate, OP-10 and water in a mass ratio of 1:2:25) and a sodium bicarbonate aqueous solution with a mass fraction of 4 wt% to water, and the mass ratio of the mixed emulsifier solution, sodium bicarbonate aqueous solution and water is 1:2:20. Then, nitrogen gas is introduced under stirring, and DFMA, BA and MMA in a mass ratio of 1:2:1:0.4 are added. Stirring is continued for 15 min to obtain an emulsion. S22. The emulsion obtained in S21 is heated to 70°C, and a 4 wt% ammonium persulfate aqueous solution is added dropwise. The reaction is then carried out for 1 hour to obtain a seed emulsion. S23. DFMA, BA, MMA and HEA in a mass ratio of 1:2:1:0.4 are added to the seed emulsion obtained in S22. Then, 4 wt% ammonium persulfate aqueous solution is added and the reaction is kept at a constant temperature for 1.5 h to obtain fluorine-modified acrylate copolymer emulsion. Example 2

[0017] A waterproof building coating, wherein the coating comprises the following components by weight: 30 parts of compound emulsion 45 parts of vinyl acetate-ethylene copolymer emulsion Dispersant (sodium polycarboxylate) 0.2 parts Defoamer (polydimethylsiloxane) 0.4 parts 1 part of film-forming aid (propylene glycol methyl ether acetate) 55 parts of sulfoaluminate cement 25 parts of ultrafine talc powder (1300 mesh) 5 parts of fumed silica The method for preparing the composite emulsion includes the following steps: S1. Disperse nano-hydroxyapatite in deionized water using ultrasonication, with a solid-liquid ratio of nano-hydroxyapatite to deionized water of 1:12. Add 6 wt% of emulsifier SDBS based on the mass of nano-hydroxyapatite and stir to obtain a mixed solution. S2. Add a semi-interpenetrating network polymer and a fluorinated modified copolymer in a mass ratio of 1:1 to the solution obtained in S1, and stir at 30°C for 50 min to obtain a composite emulsion.

[0018] The preparation of the semi-interpenetrating network polymer in S2 includes the following steps: S11. Polycaprolactone was melted at 80°C and then toluene diisocyanate was added. The molar ratio of polycaprolactone to toluene diisocyanate was 1:2-4. The mixture was then stirred and reacted for 2 hours under nitrogen protection to obtain isocyanate-terminated polycaprolactone prepolymer. S12. POSS methacryloyloxypropylcyclotetrasiloxane and hydroxymethacrylamide in a mass ratio of 1:0.8 were added to N,N-dimethylformamide and dissolved to obtain a solution with a mass fraction of 15wt%. The solution was heated to 70℃, and isocyanate-terminated polycaprolactone prepolymer was added. The mixture was stirred and reacted for 3h. S13. Add an initiator (azobisisobutyronitrile) to the reaction system obtained from S2, and continue the reaction for 2 hours to obtain a semi-interpenetrating network polymer.

[0019] The preparation method of the fluorinated modified acrylate copolymer includes the following steps: S21. Add a mixed emulsifier solution (containing sodium dodecyl sulfate, OP-10 and water in a mass ratio of 1:2:25) and a sodium bicarbonate aqueous solution with a mass fraction of 6 wt% to water, and the mass ratio of the mixed emulsifier solution, sodium bicarbonate aqueous solution and water is 1:2:20. Then, under stirring, nitrogen gas is introduced, and DFMA, BA and MMA in a mass ratio of 1:2:1:0.58 are added. Stirring is continued for 15 min to obtain an emulsion. S22. The emulsion obtained in S21 is heated to 80°C, and an 8 wt% ammonium persulfate aqueous solution is added dropwise. The reaction is then carried out for 2 hours to obtain a seed emulsion. S23. DFMA, BA, MMA and HEA in a mass ratio of 1:2:2:0.4 are added to the seed emulsion obtained in S22. Then, 4 wt% ammonium persulfate aqueous solution is added and the reaction is kept at a constant temperature for 1.5 h to obtain fluorine-modified acrylate copolymer emulsion. Example 3

[0020] A waterproof building coating, wherein the coating comprises the following components by weight: 25 parts of compound emulsion 40 parts of vinyl acetate-ethylene copolymer emulsion Dispersant (sodium polycarboxylate) 0.2 parts Defoamer (polydimethylsiloxane) 0.4 parts 1 part of film-forming aid (propylene glycol methyl ether acetate) 60 parts of sulfoaluminate cement 30 parts of ultrafine talc powder (1000 mesh) 3 parts of fumed silica The method for preparing the composite emulsion includes the following steps: S1. Disperse nano-hydroxyapatite in deionized water using ultrasonication, with a solid-liquid ratio of nano-hydroxyapatite to deionized water of 1:10. Add 5 wt% of emulsifier SDBS based on the mass of nano-hydroxyapatite and stir to obtain a mixed solution. S2. Add a semi-interpenetrating network polymer and a fluorinated modified copolymer in a mass ratio of 1:1-2 to the solution obtained in S1, and stir at 35°C for 40 min to obtain a composite emulsion.

[0021] The preparation of the semi-interpenetrating network polymer in S2 includes the following steps: S11. Polycaprolactone was melted at 80°C and then toluene diisocyanate was added. The molar ratio of polycaprolactone to toluene diisocyanate was 1:2. The mixture was then stirred and reacted for 1 hour under nitrogen protection to obtain isocyanate-terminated polycaprolactone prepolymer. S12. POSS methacryloyloxypropylcyclotetrasiloxane and hydroxymethacrylamide in a mass ratio of 1:0.8 were added to N,N-dimethylformamide and dissolved to obtain a 10wt% solution. The solution was heated to 75℃, and isocyanate-terminated polycaprolactone prepolymer was added. The mixture was stirred and reacted for 3 hours. S13. Add an initiator (benzoyl peroxide) to the reaction system obtained from S2, and continue the reaction for 2 hours to obtain a semi-interpenetrating network polymer.

[0022] The preparation method of the fluorinated modified acrylate copolymer includes the following steps: S21. Add a mixed emulsifier solution (containing sodium dodecyl sulfate, OP-10 and water in a mass ratio of 1:4:30) and an 8 wt% sodium bicarbonate aqueous solution to water, the mass ratio of the mixed emulsifier solution, sodium bicarbonate aqueous solution and water is 1:4:25, then introduce nitrogen gas under stirring, and add DFMA, BA and MMA in a mass ratio of 1:2:1:0.6, continue stirring for 18 min to obtain an emulsion; S22. The emulsion obtained in S21 is heated to 70°C, and an 8 wt% ammonium persulfate aqueous solution is added dropwise. The mixture is then reacted for 1 hour to obtain a seed emulsion. S23. DFMA, BA, MMA and HEA in a mass ratio of 1:2:1:0.8 are added to the seed emulsion obtained in S22. Then, 6 wt% ammonium persulfate aqueous solution is added and the reaction is kept at a constant temperature for 1.5 h to obtain fluorinated acrylate copolymer emulsion.

[0023] Example 4 A waterproof building coating, wherein the coating comprises the following components by weight: 28 parts of compound emulsion 42 parts of vinyl acetate-ethylene copolymer emulsion Dispersant (sodium polycarboxylate) 0.3 parts 0.5 parts of defoamer (polydimethylsiloxane) 1 part of film-forming aid (propylene glycol methyl ether acetate) 55 parts of sulfoaluminate cement 28 parts of ultrafine talc powder (1200 mesh) 3 parts of fumed silica The method for preparing the composite emulsion includes the following steps: S1. Disperse nano-hydroxyapatite in deionized water using ultrasonication, with a solid-liquid ratio of nano-hydroxyapatite to deionized water of 1:8. Add 5 wt% of emulsifier SDBS based on the mass of nano-hydroxyapatite and stir to obtain a mixed solution. S2. Add a semi-interpenetrating network polymer and a fluorinated modified copolymer in a mass ratio of 1:1 to the solution obtained in S1, and stir at 35°C for 40 min to obtain a composite emulsion.

[0024] The preparation of the semi-interpenetrating network polymer in S2 includes the following steps: S11. Polycaprolactone was melted at 75°C and then toluene diisocyanate was added. The molar ratio of polycaprolactone to toluene diisocyanate was 1:3. The mixture was then stirred and reacted for 1 hour under nitrogen protection to obtain isocyanate-terminated polycaprolactone prepolymer. S12. POSS methacryloyloxypropylcyclotetrasiloxane and hydroxymethacrylamide in a mass ratio of 1:0.9 were added to N,N-dimethylformamide to dissolve and obtain a solution with a mass fraction of 12wt%. The solution was heated to 75℃, and isocyanate-terminated polycaprolactone prepolymer was added. The mixture was stirred and reacted for 3h. S13. Add an initiator (benzoyl peroxide) to the reaction system obtained from S2, and continue the reaction for 2 hours to obtain a semi-interpenetrating network polymer.

[0025] The preparation method of the fluorinated modified acrylate copolymer includes the following steps: S21. Add a mixed emulsifier solution (containing sodium dodecyl sulfate, OP-10 and water in a mass ratio of 1:2:25) and an 8 wt% sodium bicarbonate aqueous solution to water, and the mass ratio of the mixed emulsifier solution to the sodium bicarbonate aqueous solution and water is 1:4:28. Then, under stirring, nitrogen gas is introduced, and DFMA, BA and MMA in a mass ratio of 1:2:1:0.7 are added. Stirring is continued for 20 min to obtain an emulsion. S22. The emulsion obtained in S21 is heated to 75°C, and a 6 wt% ammonium persulfate aqueous solution is added dropwise. The mixture is then reacted for 1 hour to obtain a seed emulsion. S23. DFMA, BA, MMA and HEA in a mass ratio of 1:2:1:0.6 are added to the seed emulsion obtained in S22. Then, 6 wt% ammonium persulfate aqueous solution is added and the reaction is kept at a constant temperature for 1.5 h to obtain fluorine-modified acrylate copolymer emulsion.

[0026] Example 5 A waterproof building coating, wherein the coating comprises the following components by weight: 28 parts of compound emulsion 45 parts of vinyl acetate-ethylene copolymer emulsion Dispersant (sodium polycarboxylate) 0.3 parts 0.5 parts of defoamer (polydimethylsiloxane) 1 part of film-forming aid (propylene glycol methyl ether acetate) 55 parts of sulfoaluminate cement 25 parts of ultrafine talc powder (1200 mesh) 3 parts of fumed silica The method for preparing the composite emulsion includes the following steps: S1. Disperse nano-hydroxyapatite in deionized water using ultrasonication, with a solid-liquid ratio of nano-hydroxyapatite to deionized water of 1:10. Add 6 wt% of emulsifier SDBS based on the mass of nano-hydroxyapatite and stir to obtain a mixed solution. S2. Add a semi-interpenetrating network polymer and a fluorinated modified copolymer in a mass ratio of 1:1 to the solution obtained in S1, and stir at 35°C for 40 min to obtain a composite emulsion.

[0027] The preparation of the semi-interpenetrating network polymer in S2 includes the following steps: S11. Polycaprolactone was melted at 70°C and then toluene diisocyanate was added. The molar ratio of polycaprolactone to toluene diisocyanate was 1:2. The mixture was then stirred and reacted for 1 hour under nitrogen protection to obtain isocyanate-terminated polycaprolactone prepolymer. S12. POSS methacryloyloxypropylcyclotetrasiloxane and hydroxymethacrylamide in a mass ratio of 1:0.8 were added to N,N-dimethylformamide and dissolved to obtain a 10wt% solution. The solution was heated to 74℃, and isocyanate-terminated polycaprolactone prepolymer was added. The mixture was stirred and reacted for 3h. S13. Add an initiator (benzoyl peroxide) to the reaction system obtained from S2, and continue the reaction for 2 hours to obtain a semi-interpenetrating network polymer.

[0028] The preparation method of the fluorinated modified acrylate copolymer includes the following steps: S21. Add a mixed emulsifier solution (containing sodium dodecyl sulfate, OP-10 and water in a mass ratio of 1:6:25) and a sodium bicarbonate aqueous solution with a mass fraction of 4 wt% to water, and the mass ratio of the mixed emulsifier solution, sodium bicarbonate aqueous solution and water is 1:4:25. Then, under stirring, nitrogen gas is introduced, and DFMA, BA and MMA in a mass ratio of 1:2:1:0.4 are added. Stirring is continued for 20 min to obtain an emulsion. S22. The emulsion obtained in S21 is heated to 75°C, and a 6 wt% ammonium persulfate aqueous solution is added dropwise. The mixture is then reacted for 1 hour to obtain a seed emulsion. S23. DFMA, BA, MMA and HEA in a mass ratio of 1:2:1:0.4 are added to the seed emulsion obtained in S22. Then, 6 wt% ammonium persulfate aqueous solution is added and the reaction is kept at a constant temperature for 1.5 h to obtain fluorine-modified acrylate copolymer emulsion.

[0029] Example 6 A waterproof building coating, wherein the coating comprises the following components by weight: 25 parts of compound emulsion 40 parts of vinyl acetate-ethylene copolymer emulsion Dispersant (sodium polycarboxylate) 0.2 parts Defoamer (polydimethylsiloxane) 0.6 parts 1 part of film-forming aid (propylene glycol methyl ether acetate) 58 parts of sulfoaluminate cement 28 parts of ultrafine talc powder (1000 mesh) 3 parts of fumed silica The method for preparing the composite emulsion includes the following steps: S1. Disperse nano-hydroxyapatite in deionized water using ultrasonication, with a solid-liquid ratio of nano-hydroxyapatite to deionized water of 1:9. Add 6 wt% of emulsifier SDBS based on the mass of nano-hydroxyapatite and stir to obtain a mixed solution. S2. Add a semi-interpenetrating network polymer and a fluorinated modified copolymer in a mass ratio of 1:1 to the solution obtained in S1, and stir at 35°C for 40 min to obtain a composite emulsion.

[0030] The preparation of the semi-interpenetrating network polymer in S2 includes the following steps: S11. Polycaprolactone was melted at 76°C and then toluene diisocyanate was added. The molar ratio of polycaprolactone to toluene diisocyanate was 1:2. The mixture was then stirred and reacted for 1 hour under nitrogen protection to obtain isocyanate-terminated polycaprolactone prepolymer. S12. POSS methacryloyloxypropylcyclotetrasiloxane and hydroxymethacrylamide in a mass ratio of 1:0.8 were added to N,N-dimethylformamide and dissolved to obtain a solution with a mass fraction of 13wt%. The solution was heated to 75℃, and isocyanate-terminated polycaprolactone prepolymer was added. The mixture was stirred and reacted for 3 hours. S13. Add an initiator (benzoyl peroxide) to the reaction system obtained from S2, and continue the reaction for 2 hours to obtain a semi-interpenetrating network polymer.

[0031] The preparation method of the fluorinated modified acrylate copolymer includes the following steps: S21. Add a mixed emulsifier solution (containing sodium dodecyl sulfate, OP-10 and water in a mass ratio of 1:2:25) and an 8 wt% sodium bicarbonate aqueous solution to water, and the mass ratio of the mixed emulsifier solution, sodium bicarbonate aqueous solution and water is 1:2:25. Then, under stirring, nitrogen gas is introduced, and DFMA, BA and MMA in a mass ratio of 1:2:1:0.4 are added. Stirring is continued for 20 min to obtain an emulsion. S22. The emulsion obtained in S21 is heated to 75°C, and a 6 wt% ammonium persulfate aqueous solution is added dropwise. The mixture is then reacted for 1 hour to obtain a seed emulsion. S23. DFMA, BA, MMA and HEA in a mass ratio of 1:2:1:0.6 are added to the seed emulsion obtained in S22. Then, 6 wt% ammonium persulfate aqueous solution is added and the reaction is kept at a constant temperature for 1.5 h to obtain fluorine-modified acrylate copolymer emulsion.

[0032] Example 7 A waterproof building coating, wherein the coating comprises the following components by weight: 30 parts of compound emulsion 45 parts of vinyl acetate-ethylene copolymer emulsion Dispersant (sodium polycarboxylate 0.4 parts) Defoamer (polydimethylsiloxane) 0.4 parts 1 part of film-forming aid (propylene glycol methyl ether acetate) 55 parts of sulfoaluminate cement 29 parts of ultrafine talc powder (1300 mesh) 4 parts of fumed silica The method for preparing the composite emulsion includes the following steps: S1. Disperse nano-hydroxyapatite in deionized water using ultrasonication, with a solid-liquid ratio of nano-hydroxyapatite to deionized water of 1:8. Add 6 wt% of emulsifier SDBS based on the mass of nano-hydroxyapatite and stir to obtain a mixed solution. S2. Add a semi-interpenetrating network polymer and a fluorinated modified copolymer in a mass ratio of 1:1 to the solution obtained in S1, and stir at 40°C for 20 min to obtain a composite emulsion.

[0033] The preparation of the semi-interpenetrating network polymer in S2 includes the following steps: S11. Polycaprolactone was melted at 75°C and then toluene diisocyanate was added. The molar ratio of polycaprolactone to toluene diisocyanate was 1:2. The mixture was then stirred and reacted for 1 hour under nitrogen protection to obtain isocyanate-terminated polycaprolactone prepolymer. S12. POSS methacryloyloxypropylcyclotetrasiloxane and hydroxymethacrylamide in a mass ratio of 1:0.8 were added to N,N-dimethylformamide and dissolved to obtain a solution with a mass fraction of 12wt%. The solution was heated to 75℃, and isocyanate-terminated polycaprolactone prepolymer was added. The mixture was stirred and reacted for 3 hours. S13. Add an initiator (benzoyl peroxide) to the reaction system obtained from S2, and continue the reaction for 2 hours to obtain a semi-interpenetrating network polymer.

[0034] The preparation method of the fluorinated modified acrylate copolymer includes the following steps: S21. Add a mixed emulsifier solution (containing sodium dodecyl sulfate, OP-10 and water in a mass ratio of 1:2:30) and a sodium bicarbonate aqueous solution with a mass fraction of 4 wt% to water, and the mass ratio of the mixed emulsifier solution, sodium bicarbonate aqueous solution and water is 1:4:20. Then, under stirring, nitrogen gas is introduced, and DFMA, BA and MMA in a mass ratio of 1:2:2:0.8 are added. Stirring is continued for 32 min to obtain an emulsion. S22. The emulsion obtained in S21 is heated to 75°C, and a 7wt% ammonium persulfate aqueous solution is added dropwise. The mixture is then reacted for 1 hour to obtain a seed emulsion. S23. DFMA, BA, MMA and HEA in a mass ratio of 1:2:1:0.8 are added to the seed emulsion obtained in S22. Then, an 8 wt% ammonium persulfate aqueous solution is added and the reaction is kept at a constant temperature for 1.5 h to obtain a fluorinated acrylate copolymer emulsion.

[0035] Comparative Example 1 The difference between this comparative example and Example 7 is that no composite emulsion was added; otherwise, they are the same as in Example 7.

[0036] The difference between this comparative example and Example 7 is that no fluorinated modified copolymer was added to the composite emulsion; otherwise, they are the same as in Example 7.

[0037] The difference between this comparative example and Example 7 is that the amount of sulfoaluminate cement used is 45 parts, while the rest are the same as in Example 7.

[0038] The difference between this comparative example and Example 7 is that HEA was not added to the fluorinated copolymer, while all other aspects are the same as in Example 7.

[0039] The difference between this comparative example and Example 7 is that the heating temperature in S11 is 90°C.

[0040] Performance testing The coatings obtained in Examples 1-7 and Comparative Examples 1-5 of this invention were applied twice to a concrete substrate with a 12-hour interval between applications. The coating thickness was 1.5 mm. The concrete substrate was pre-wetted and then cured at 23°C and 50% humidity for 96 hours. After demolding and drying, samples were obtained. The samples were cut into specimen blocks with dimensions of 90 mm × 25 mm × 1.5 mm. Tensile properties were tested according to GB / T 16777-2008. The specimens were heat-aged at 80°C for 168 hours, and their tensile properties after heat aging were tested. The retention rate of tensile properties after heat aging was calculated to evaluate their heat aging resistance. The tensile properties of the sample after alkali aging were tested after 168 hours in a saturated solution of 0.1% sodium hydroxide and calcium hydride, and the retention rate of tensile properties after alkali aging was calculated to evaluate its alkali aging resistance. The sample was then placed in a UV chamber and aged at 45℃ for 240 hours, and its tensile properties after UV aging were tested, and the retention rate of tensile properties after UV aging was calculated to evaluate its UV aging resistance. Referring to GB / T 23445-2009, a coating with dimensions of 40mm × 40mm × 1.5mm was prepared on the substrate, cured under standard experimental conditions for 96 hours, and dried at 40℃ for 48 hours. The bond strength was tested. Referring to GB / T 23445-2009, the impermeability of the sample after heat aging and UV aging was tested. The impermeability was determined by whether water permeation occurred under a pressure of 0.7MPa for 2 hours to evaluate its waterproof performance. The test results are shown in the table below.

[0041] Table 1

[0042] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A waterproof building coating, characterized in that: The coating comprises the following components by weight: 25-30 parts of compound emulsion 40-45 parts of vinyl acetate-ethylene copolymer emulsion Dispersant 0.2-0.4 parts Defoamer 0.4-0.6 parts 1-2 parts of film-forming aid 55-60 parts of sulfoaluminate cement 25-30 parts of ultrafine talc 3-5 parts of fumed silica.

2. The method for preparing the waterproof building coating according to claim 1, characterized in that: The dispersant is sodium polycarboxylate, the defoamer is an organosilicon defoamer, specifically polydimethylsiloxane, the film-forming aid is propylene glycol methyl ether acetate, and the ultrafine talc powder has a mesh size of 1000-1300 mesh.

3. The method for preparing the waterproof building coating according to claim 1, characterized in that: The method for preparing the composite emulsion includes the following steps: S1. Disperse nano-hydroxyapatite in deionized water using ultrasonication, with a solid-liquid ratio of nano-hydroxyapatite to deionized water of 1:8-12. Add 5-8 wt% of emulsifier SDBS based on the mass of nano-hydroxyapatite and stir to obtain a mixed solution. S2. Add a semi-interpenetrating network polymer and a fluorinated modified copolymer in a mass ratio of 1:1-2 to the solution obtained in S1, and stir at 30-40℃ for 20-50 min to obtain a composite emulsion.

4. The method for preparing the waterproof building coating according to claim 3, characterized in that: The preparation of the semi-interpenetrating network polymer in S2 includes the following steps: S11. Polycaprolactone is melted at 70~80℃ and then toluene diisocyanate is added. The molar ratio of polycaprolactone to toluene diisocyanate is 1:2-4. The mixture is then stirred and reacted under nitrogen protection for 1~2 hours to obtain isocyanate-terminated polycaprolactone prepolymer. S12. POSS methacryloyloxypropylcyclotetrasiloxane and hydroxymethacrylamide in a mass ratio of 1:0.8-1 are added to N,N-dimethylformamide and dissolved to obtain a solution with a mass fraction of 10-15wt%. The temperature is raised to 70-80℃, and isocyanate-terminated polycaprolactone prepolymer is added. The mixture is stirred and reacted for 3-4 hours. S13. Add an initiator to the reaction system obtained from S2 and continue the reaction for 2-3 hours to obtain a semi-interpenetrating network polymer.

5. The method for preparing the waterproof building coating according to claim 3, characterized in that: The preparation method of the fluorinated modified acrylate copolymer includes the following steps: S21. Add a mixed emulsifier solution and sodium bicarbonate aqueous solution in a mass ratio of 1:2-5:20-30 to water, then introduce nitrogen gas under stirring, and add DFMA, BA, and MMA in a mass ratio of 1:2-3:1-2:0.4-0.

8. Continue stirring for 15-35 minutes to obtain an emulsion. S22. Heat the emulsion obtained in S21 to 70-80℃, add dropwise an aqueous solution of ammonium persulfate with a mass fraction of 4-8wt%, and then react for 1-2 hours to obtain a seed emulsion; S23. Add DFMA, BA, MMA, and HEA in a mass ratio of 1:2-3:1-2:0.4-0.8 to the seed emulsion obtained in S22, followed by adding an aqueous solution of ammonium persulfate with a mass fraction of 4-8 wt%, and keep the reaction at a warm temperature for 1.5-2 hours to obtain a fluorinated acrylate copolymer emulsion.

6. The method for preparing the waterproof building coating according to claim 4, characterized in that: The initiator in S13 is either azobisisobutyronitrile or benzoyl peroxide.

7. The method for preparing the waterproof building coating according to claim 5, characterized in that: The mixed emulsifier in S21 contains sodium dodecyl sulfate, OP-10, and water in a mass ratio of 1:2-8:25-35.

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