A self-healing polymer emulsion cement-based waterproof coating and its preparation method

Abstract

The present invention belongs to the technical field of building waterproofing, and discloses a self-healing polymer emulsion cement-based waterproof coating and a preparation method thereof. The waterproof coating of the present invention comprises a liquid material and a powder material with a mass ratio of 1:(1-1.5); the liquid material comprises the following raw materials in parts by mass: 90-96 parts of a polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and hydrazone bonds, 1-3 parts of an antifoaming agent, and 1-3 parts of a film-forming auxiliary; the powder material comprises the following raw materials in parts by mass: 40-50 parts of cement, 25-45 parts of stone powder, 10-20 parts of heavy calcium carbonate, 3-8 parts of calcium hydroxide, 0.3-1 part of a water reducing agent, 0.2-1.2 parts of a β-cyclodextrin / complexing agent inclusion compound, and 0.08-0.32 parts of PVA fiber. The coating film formed by the waterproof coating of the present invention can achieve self-healing for both micro-cracks and relatively wide cracks, and has a long-term and effective crack self-healing effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of building waterproofing, and particularly relates to a self-healing polymer emulsion cement-based waterproof coating and a preparation method thereof. Background Art

[0002] Building leakage has always been a difficult problem in the building field and is known as the "cancer of buildings". Once a building leaks, it will not only damage the appearance quality and durability of the building, but in severe cases, it will also damage the engineering structure, causing it to lose its service function and even endangering people's lives. Therefore, building waterproofing has always received extensive attention and emphasis. Currently, the commonly used building waterproof materials mainly include waterproof coiled materials, waterproof coatings, and building sealing materials.

[0003] Polymer emulsion cement-based waterproof coatings are an important type of waterproof coatings. Polymer emulsion cement-based waterproof coatings are prepared by using polymer emulsions such as acrylate and ethylene-vinyl acetate and cement as the main raw materials, supplemented by fillers and various additives, and cured into a film through water evaporation and cement hydration reactions. Such coatings have the advantages of the ductility and waterproofness of polymer coatings, as well as the high strength and good adhesion to the substrate of hydraulic materials, and are a kind of material that combines rigidity and flexibility; at the same time, it uses water as a dispersant, overcoming the problem of solvent-based coatings being prone to polluting the environment and being beneficial to environmental protection. Therefore, it has received extensive attention and developed rapidly since its advent. However, in actual engineering applications, due to various reasons such as the cracking of the substrate pulling the coating film to cause fine cracks, if the cracked polymer emulsion cement-based waterproof coating cannot be repaired in time, the building will leak.

[0004] Chinese Patent CN110510932A discloses a self-healing polymer cement waterproof coating and a preparation method thereof. The waterproof coating includes a polymer emulsion, a cement-based powder, and a hydrogel, and realizes the self-healing of the waterproof coating film through the water absorption and swelling of the hydrogel, solving the problem that the coating film cracking cannot be repaired. However, when the external environment is dry, the hydrogel will release the absorbed water and gradually shrink, and the cracks healed by the swelling of the hydrogel will crack again, and when the crack width is large, the hydrogel cannot make it self-heal.

[0005] Chinese Patent CN105969143A discloses a self-repairing reactive polymer cement waterproof coating and a preparation method thereof. The repair material is coated with a water-absorbing and swelling material to form microcapsules. When the coating is pulled and cracked along with the substrate, the internal capsules are exposed at the fracture. Its water-absorbing wall material absorbs water and becomes soft, swells and breaks, and the internal repair material flows out and quickly solidifies and gels when encountering water to block the cracks, realizing self-repair. However, the amount of repair agent encapsulated by the microcapsules is small and the fluidity is limited, and it is difficult to completely fill the cracks; and the repair of this method is one-time, and when the repair agent in the capsule flows out, it will lose the ability to repair again.

[0006] Chinese Patent CN102173728A discloses a self-healing polymer cement waterproof coating and its preparation process. By using low-alkali rapid-hardening sulphoaluminate cement, it has a self-repairing effect on fine cracks. However, relying only on the early activity of cement particles can only repair microcracks and cannot heal wider cracks, and it only has a self-repairing effect in the early stage. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a self-repairing polymer emulsion cement-based waterproof coating and its preparation method in view of the deficiencies of the prior art. The coating film formed by this waterproof coating can achieve self-healing for both microcracks and wider cracks, and has a long-term and effective crack self-repairing effect.

[0008] To solve the technical problems proposed by the present invention, the present invention provides a self-repairing polymer emulsion cement-based waterproof coating, which includes liquid material and powder material with a mass ratio of 1:(1 - 1.5); the liquid material includes the following raw materials in parts by mass: 90 - 96 parts of polyurethane-modified acrylate copolymer emulsion containing diselenide bond and acylhydrazone bond, 1 - 3 parts of defoamer, 1 - 3 parts of film-forming aid; the powder material includes the following raw materials in parts by mass: 40 - 50 parts of cement, 25 - 45 parts of stone powder, 10 - 20 parts of heavy calcium carbonate, 3 - 8 parts of calcium hydroxide, 0.3 - 1 part of water reducer, 0.2 - 1.2 parts of β-cyclodextrin / complexing agent inclusion compound, 0.08 - 0.32 parts of PVA fiber.

[0009] In the above solution, the polyurethane-modified acrylate copolymer emulsion containing diselenide bond and acylhydrazone bond is formed by mixing a hydrazide group-terminated polyurethane emulsion containing diselenide bond and an acrylate copolymer emulsion containing ketone carbonyl group.

[0010] Furthermore, the mass ratio of the hydrazide group-terminated polyurethane emulsion containing diselenide bond to the acrylate copolymer emulsion containing ketone carbonyl group is 1:(1.5 - 2).

[0011] Furthermore, the preparation method of the acrylate copolymer emulsion containing ketone carbonyl group is as follows:

[0012] S1. Mix soft monomer, hard monomer, methacrylic acid, and 2-

〔2-methyl-1-oxy-2-propenyl〕oxy

[0013] S2. Dissolve the emulsifier in water, stir at high speed, then add the mixed monomer, and continue to stir at high speed to form a monomer pre-emulsion;

[0014] S3. Take part of the monomer pre-emulsion and part of the initiator and add them to the reaction kettle, heat up to 72 - 75 °C to initiate. When the blue phase appears in the system, drop the remaining monomer pre-emulsion and the remaining initiator into the reaction kettle;

[0015] S4. After the dropping is completed, the temperature is raised to 75 - 90 °C and kept warm for 30 - 40 min, then cooled to room temperature. After adjusting the pH value to 7 - 8 with ammonia water, filtration is carried out to obtain an acrylate copolymer emulsion containing a ketone carbonyl group.

[0016] Further, the soft monomer is one of ethyl acrylate, butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, n-octyl methacrylate, isobutyl acrylate, decyl acrylate, lauryl methacrylate, 11 vinyl versatate, tridecyl methacrylate.

[0017] Further, the hard monomer is one of vinyl acetate, styrene, methyl methacrylate, C9 vinyl versatate, acrylonitrile, ethyl methacrylate, 2-hydroxypropyl methacrylate, isobornyl methacrylate, isobutyl methacrylate, acrylamide, cyclohexyl methacrylate.

[0018] Further, the mass ratio of the soft monomer, hard monomer, methacrylic acid, and 2-

〔2-methyl-1-oxy-2-propenyl〕oxy

[0019] Further, the emulsifier is an MS-1 type emulsifier, and the mass of the emulsifier is 0.12 - 0.16% of the mass of the mixed monomers.

[0020] Further, the mass ratio of water to the mixed monomers in step S2 is (1 - 1.6):1.

[0021] Further, the stirring rate of the high-speed stirring is 400 - 500 r / min. After the emulsifier is dissolved in water, stirring is carried out for 20 - 30 min, and after adding the mixed monomers, stirring is carried out for 30 - 55 min.

[0022] Further, the initiator is potassium persulfate, and the mass of the initiator is 0.6 - 0.8% of the mass of the mixed monomers.

[0023] Further, in step S3, first take 1 / 5 - 2 / 5 of the mass of the monomer pre-emulsion and 1 / 2 - 3 / 5 of the mass of the initiator for initiation, and the dropping time of the remaining monomer pre-emulsion and the remaining initiator is controlled within 2 - 4 h.

[0024] Further, the preparation method of the hydrazide-terminated polyurethane emulsion containing a diselenide bond is as follows:

[0025] 1) After dehydrating the polyester diol monomer, add it together with dimethylolpropionic acid and diisocyanate monomer into a reaction kettle. Under nitrogen protection, heat up to 70 - 90 °C and stir for 2 - 4 h. After the reaction, add an organic solvent to adjust the viscosity of the system to 600 - 1300 cp;

[0026] 2) Continue to add triethanolamine into the reaction kettle. After stirring for 15 - 30 min, cool down to 40 - 55 °C, then add water and 3,3'-diselenodipropionyl hydrazide, and continue to stir for 2 - 4 h. Remove the organic solvent to obtain a hydrazide-terminated polyurethane emulsion containing diselenide bonds.

[0027] Further, the polyester diol monomer is one of poly(butylene adipate) diol, polycaprolactone diol, neopentyl glycol adipate diol, ethylene glycol adipate diol, ethylene glycol butylene glycol adipate diol, 3-methylpentanediol adipate diol.

[0028] Further, the relative molecular mass of the polyester diol monomer is 1000 - 3000.

[0029] Further, the diisocyanate monomer is one of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, naphthalene diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate.

[0030] Further, the organic solvent is one of acetone and butanone.

[0031] Further, the molar ratio of the isocyanate group in the diisocyanate monomer to the hydroxyl group in the polyester diol is (1.2 - 1.5):1.

[0032] Further, the mass of dimethylolpropionic acid is 3 - 5% of the sum of the masses of the polyester diol monomer and the diisocyanate monomer.

[0033] Further, the molar ratio of triethanolamine to dimethylolpropionic acid is (1 - 1.2):1.

[0034] Further, in step 2), the mass of water is 2 - 3 times the sum of the masses of the polyester diol monomer and the diisocyanate monomer.

[0035] Further, the mass of 3,3'-diselenodipropionyl hydrazide is 2 - 4% of the sum of the masses of the polyester diol monomer and the diisocyanate monomer.

[0036] Further, the preparation method of 3,3'-diselenodipropionyl hydrazide is:

[0037] ① Add 3,3'-diselenodipropionic acid, ethanol, methanesulfonic acid, and cyclohexane into a three-necked flask, heat up and stir for reflux and water separation reaction. After the reaction, distill off cyclohexane, wash the remaining product until the pH is neutral, and dry to obtain diethyl 3,3'-diselenodipropionate;

[0038] ② Add diethyl 3,3'-diselenodipropionate, hydrazine hydrate, and ethanol into a three-necked flask, heat up and stir for reflux reaction. After the reaction ends, wait for the reaction solution to cool to room temperature and then perform suction filtration. Wash and dry the solid to obtain 3,3'-diselenodipropionyl hydrazide.

[0039] Furthermore, the mass parts of each raw material in step ① are: 0.3 - 1 part of 3,3'-diselenodipropionic acid, 7.9 - 15.8 parts of ethanol, 0.05 - 0.12 part of methanesulfonic acid, and 9.4 - 15.6 parts of cyclohexane.

[0040] Furthermore, the mass parts of each raw material in step ② are: 0.4 - 0.8 part of diethyl 3,3'-diselenodipropionate, 0.1 - 0.3 part of hydrazine hydrate, and 15.8 - 31.6 parts of ethanol.

[0041] Furthermore, the concentration of the hydrazine hydrate is 80% - 95%.

[0042] Furthermore, the reaction temperature of the stirring reflux and water separation reaction in step ① is 100 - 110 °C, and the reaction time is 6 - 8 h.

[0043] Furthermore, the reaction temperature of the stirring reflux reaction in step ② is 90 - 95 °C, and the reaction time is 5 - 6 h.

[0044] In the above solution, the defoamer is an organosilicon defoamer.

[0045] In the above solution, the film-forming aid is an alcohol-based film-forming aid.

[0046] In the above solution, the cement is ordinary Portland cement with a fineness of 320 - 380 m 2 / kg.

[0047] In the above solution, the stone powder is granite stone powder with a fineness of 150 - 250 mesh.

[0048] In the above solution, the water reducer is a polycarboxylate superplasticizer with a water reduction rate of 15 - 25%.

[0049] In the above solution, the preparation method of the β-cyclodextrin / complexing agent inclusion compound is: mix β-cyclodextrin with water evenly, add dodecyltrimethylammonium chloride and heat with stirring, then add the complexing agent and continue heating with stirring, followed by ultrasonic dispersion treatment, and finally perform centrifugal spray drying on the mixed solution to obtain the β-cyclodextrin / complexing agent inclusion compound.

[0050] Furthermore, in the preparation process of the β-cyclodextrin / complexing agent inclusion compound, the mass parts of each raw material are as follows: 100 parts of β-cyclodextrin, 200 - 300 parts of water, 10 - 20 parts of dodecyl trimethyl ammonium chloride, and 30 - 50 parts of complexing agent.

[0051] Furthermore, the complexing agent is one or a mixture of two of sodium gluconate and sodium citrate.

[0052] Furthermore, after adding the dodecyl trimethyl ammonium chloride, the heating temperature is 70 - 80 °C, the stirring rate is 150 - 200 rpm, and the stirring time is 20 - 30 min.

[0053] Furthermore, after adding the complexing agent, the heating temperature is 70 - 80 °C, the stirring rate is 200 - 300 rpm, and the stirring time is 20 - 30 min.

[0054] Furthermore, the time for ultrasonic dispersion treatment is 10 - 15 min.

[0055] Furthermore, the inlet air temperature for centrifugal spray drying is 180 - 200 °C, and the exhaust air temperature is 80 - 90 °C.

[0056] Furthermore, the particle size of the β-cyclodextrin / complexing agent inclusion compound is 200 - 300 mesh, and the moisture content ≤ 2%.

[0057] In the above solution, the length of the PVA fiber is 3 - 5 mm, and the diameter is 12 - 18 μm.

[0058] The present invention also provides a preparation method of a self-healing polymer emulsion cement-based waterproof coating, including the following steps:

[0059] a. Sequentially add an antifoaming agent and a film-forming aid into a feed barrel, and then add a polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and hydrazone bonds, and stir evenly to obtain a liquid material;

[0060] b. Add cement, stone powder, heavy calcium carbonate, calcium hydroxide, a water reducing agent, a β-cyclodextrin / complexing agent inclusion compound, and PVA fiber into another feed barrel, and stir evenly to obtain a powder material;

[0061] c. Before use, slowly add the powder material into the liquid material, and stir while adding until a uniformly fine slurry is stirred to obtain a self-healing polymer emulsion cement-based waterproof coating.

[0062] In the above solution, the coating film formed by the waterproof coating can achieve self-healing for both micro-cracks and relatively wide cracks; for micro-cracks with a width ≤ 0.10 mm, self-repair can be achieved within 24 hours through the rapid cooperative reversible response of diselenide bonds and acylhydrazone bonds; for relatively wide cracks with a width of 0.1 - 0.3 mm, self-repair can be achieved within 18 days through the continuous slow-release effect of β-cyclodextrin / complexing agent inclusion compounds and their synergistic effect with PVA fibers.

[0063] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0064] (1) In the present invention, a hydrazide compound containing a diselenide bond, 3,3'-diselenodipropionyl hydrazide, is prepared to successfully introduce dynamic reversible diselenide bonds into the polyurethane emulsion and cap it with hydrazide groups, and then it is mixed with an acrylate copolymer emulsion containing a ketone carbonyl group to prepare a polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and acylhydrazone bonds by using the ketone-hydrazide condensation reaction. A variety of dynamic reversible covalent bonds introduced into the polymer main chain, namely diselenide bonds and acylhydrazone bonds, can achieve dual dynamic exchange under natural environmental conditions, quickly repair micro-cracks and damages, not only greatly improving the self-repair efficiency, but also enabling repeated self-repair.

[0065] (2) In the present invention, a complexing agent reacts with calcium ions in the polymer emulsion cement-based waterproof coating to form a calcium complex, which migrates to the cracks with water and reacts with carbonate ions in the crack fluid to form calcium carbonate precipitation to repair relatively wide cracks, while the complexing agent can return to its original state and react with free calcium ions repeatedly to achieve long-term self-repair of the cracks. However, the complexing agent theoretically does not consume and can be effective for a long time, but actually it will dissolve in water and be lost, thereby reducing its long-term self-repair effect on the cracks in the polymer emulsion cement-based waterproof coating film. In the present invention, dodecyl trimethyl ammonium chloride is introduced into the inner cavity of β-cyclodextrin to form β-cyclodextrin inclusion dodecyl trimethyl ammonium chloride, and then, by using the electrostatic interaction between the positively charged dodecyl trimethyl ammonium chloride and the negatively charged complexing agent, the complexing agent is successfully introduced into the inner cavity of β-cyclodextrin, thereby obtaining a β-cyclodextrin / complexing agent inclusion compound. The β-cyclodextrin / complexing agent inclusion compound can control the release of the complexing agent to maintain the long-term effectiveness of the self-repair effect of the complexing agent on the cracks in the polymer emulsion cement-based waterproof coating film, significantly improving its high-efficiency and long-term self-repair of relatively wide cracks.

[0066] (3) The PVA fibers introduced in the present invention play a unique "bond" role. On the one hand, the PVA fibers distributed in the polymer cement system can effectively disperse the stress concentration effect under external load, significantly improve the crack control ability of the polymer cement matrix, and provide favorable conditions for the self-healing of cracks; on the other hand, the hydrophilic property of the PVA fibers causes a large number of water molecules to gather at the cracks, and at the same time attracts the migration of a large number of β-cyclodextrin / complexing agent inclusion compounds with a large number of hydroxyl groups on the surface to this place and release them, providing a large number of nucleation sites for the generation of self-healing products, and significantly promoting the self-repair at the cracks. Description of the Drawings

[0067] Figure 1 It is a diagram showing the change of cracks before and after self-healing of the coating film formed by the self-healing polymer emulsion cement-based waterproof coating in Example 1 during curing in a natural environment (23±2°C, RH 50±10%).

[0068] Figure 2 It is a diagram showing the change of cracks before and after self-healing of the coating film formed by the self-healing polymer emulsion cement-based waterproof coating in Example 2 during curing in a humid environment (20°C, RH 95%). Detailed Embodiments

[0069] To better understand the present invention, the content of the present invention will be further clarified below in conjunction with embodiments, but the content of the present invention is not limited to the following embodiments.

[0070] In the following embodiments, the defoaming agent used is AFE-1410; the film-forming aid is ethylene glycol; the cement is ordinary Portland cement with a fineness of 350m 2 / kg; the stone powder is granite stone powder with a fineness of 200 mesh; the water reducing agent is PC-1030 with a water reducing rate of 19%; the length of the PVA fiber is 3mm and the diameter is 15μm; the concentration of hydrazine hydrate is 85%; the above raw materials are all commercially available products.

[0071] Example 1

[0072] A self-healing polymer emulsion cement-based waterproof coating, comprising a liquid material and a powder material with a mass ratio of 1:1; the liquid material comprises the following raw materials in parts by mass: 92 parts of a polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and hydrazone bonds, 1 part of a defoaming agent, 1 part of a film-forming aid; the powder material comprises the following raw materials in parts by mass: 40 parts of cement, 25 parts of stone powder, 15 parts of heavy calcium carbonate, 5 parts of calcium hydroxide, 0.3 part of a water reducing agent, 0.4 part of a β-cyclodextrin / complexing agent inclusion compound, 0.12 part of PVA fiber.

[0073] In this embodiment, the preparation method of the self-healing polymer emulsion cement-based waterproof coating comprises the following steps:

[0074] a. Add the defoamer and film-forming aid to the drum in sequence, then add the polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and acylhydrazone bonds, and stir with an electric stirrer for 10 - 15 min to obtain the liquid material.

[0075] b. Add cement, stone powder, heavy calcium carbonate, calcium hydroxide, water reducer, β-cyclodextrin / complexing agent inclusion compound, and PVA fiber to another drum, and stir with an electric stirrer for 10 - 20 min to obtain the powder material.

[0076] c. Before use, slowly add the powder material to the liquid material while stirring until a uniform and delicate slurry is formed to obtain the self-healing polymer emulsion cement-based waterproof coating.

[0077] In this example, the preparation method of the polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and acylhydrazone bonds includes the following steps:

[0078] 1) Prepare the acrylate copolymer emulsion containing ketone carbonyl

[0079] ① Mix butyl acrylate, cyclohexyl methacrylate, methacrylic acid, and 2-

〔2-methyl-1-oxy-2-propenyl〕oxy

[0080] ② Dissolve 0.14 g of MS-1 type emulsifier in 100 g of deionized water, stir at 400 - 500 r / min for 20 min, add 100 g of the mixed monomer, and continue to stir for 40 min to form a monomer pre-emulsion.

[0081] ③ Take 2 / 5 of the mass of the monomer pre-emulsion and 1 / 2 of the mass of the initiator (0.3 g of potassium persulfate) and add them to the reaction kettle, heat up to 75 °C for initiation. When a blue phase appears in the system, add the remaining monomer pre-emulsion and the remaining initiator (0.3 g of potassium persulfate) dropwise to the reaction kettle, and control the dropping to be completed within 2 - 3 h.

[0082] ④ After the dropping is completed, heat up to 80 °C and keep warm for 30 min, cool to room temperature, neutralize with ammonia water to a pH value of 7 - 8, and filter to obtain the acrylate copolymer emulsion containing ketone carbonyl.

[0083] 2) Prepare 3,3'-diselenodipropionylhydrazide

[0084] ① Add 0.7 parts of 3,3'-diselenodipropionic acid, 9.5 parts of ethanol, 0.08 parts of methanesulfonic acid, and 11.7 parts of cyclohexane to a three-necked flask, heat up to 100 °C, stir and reflux for water separation reaction for 8 h, rotary evaporate to remove cyclohexane, wash the remaining product with deionized water and Na2CO3 solution for multiple times until the pH is neutral, and dry to obtain diethyl 3,3'-diselenodipropionate.

[0085] ② Add 0.5 part of diethyl 3,3'-diselenodipropionate, 0.18 part of hydrazine hydrate and 19.7 parts of ethanol into a three-necked flask, heat up to 95 °C and stir under reflux for 5 h. After cooling to room temperature, perform suction filtration, wash the filter cake with deionized water multiple times, and then dry it under vacuum to obtain 3,3'-diselenodipropionyl hydrazide;

[0086] 3) Preparation of hydrazide group-terminated polyurethane emulsion containing diselenide bond

[0087] ① Poly(1,4-butylene adipate) diol (relative molecular mass of 2000) is dehydrated under vacuum at 110 °C for 2 h, and then added into a reaction kettle together with dimethylolpropionic acid and isophorone diisocyanate. Under nitrogen protection, heat up to 80 °C and stir for 3 h. After the reaction, add acetone to adjust the viscosity of the system to 1000 cp; among them, the molar ratio of the isocyanate group in isophorone diisocyanate to the hydroxyl group in poly(1,4-butylene adipate) diol is 1.2:1, and the mass of dimethylolpropionic acid is 3% of the sum of the masses of poly(1,4-butylene adipate) diol and isophorone diisocyanate;

[0088] ② Continue to add triethanolamine in an equimolar amount to dimethylolpropionic acid into the reaction kettle, stir for 20 min, then cool down to 40 °C, and then add deionized water 2.5 times the sum of the masses of poly(1,4-butylene adipate) diol and isophorone diisocyanate and 3,3'-diselenodipropionyl hydrazide 2% of the sum of the masses of poly(1,4-butylene adipate) diol and isophorone diisocyanate. After stirring for 3 h, distill off acetone under reduced pressure at 40 °C for 3 h to obtain a hydrazide group-terminated polyurethane emulsion containing diselenide bond;

[0089] 4) Preparation of polyurethane-modified acrylate copolymer emulsion containing diselenide bond and acylhydrazone bond

[0090] Mix the hydrazide group-terminated polyurethane emulsion containing diselenide bond and the acrylate copolymer emulsion containing ketone carbonyl group evenly according to a mass ratio of 1:1.5 to obtain a polyurethane-modified acrylate copolymer emulsion containing diselenide bond and acylhydrazone bond.

[0091] In this example, the preparation method of the β-cyclodextrin / complexing agent inclusion complex includes the following steps:

[0092] After mixing 100 parts of β-cyclodextrin with 250 parts of deionized water evenly, 16 parts of dodecyl trimethyl ammonium chloride were added, heated to 80 °C and stirred at 150 rpm for 25 min. Then 40 parts of sodium gluconate were added, and stirring was continued at 80 °C at 200 rpm for 25 min. Subsequently, ultrasonic dispersion treatment was carried out for 15 min. Finally, the mixed solution was centrifugally spray-dried, controlling the inlet air temperature at 200 °C and the exhaust air temperature at 90 °C, and the β-cyclodextrin / complexing agent inclusion compound with a particle size of 200 mesh and a moisture content of 1.5% was obtained.

[0093] Example 2

[0094] A self-healing polymer emulsion cement-based waterproof coating, including liquid material and powder material with a mass ratio of 1:1.2; the liquid material includes the following raw materials in parts by mass: 95 parts of polyurethane-modified acrylate copolymer emulsion containing diselenide bond and acylhydrazone bond, 2 parts of defoaming agent, 2 parts of film-forming aid; the powder material includes the following raw materials in parts by mass: 45 parts of cement, 33 parts of stone powder, 16 parts of heavy calcium carbonate, 6 parts of calcium hydroxide, 0.5 part of water reducing agent, 1.2 parts of β-cyclodextrin / complexing agent inclusion compound, 0.2 part of PVA fiber.

[0095] In this example, the preparation method of the self-healing polymer emulsion cement-based waterproof coating includes the following steps:

[0096] a. Add the defoaming agent and film-forming aid into the bucket in sequence, then add the polyurethane-modified acrylate copolymer emulsion containing diselenide bond and acylhydrazone bond, and stir with an electric stirrer for 10 - 15 min to obtain the liquid material;

[0097] b. Add cement, stone powder, heavy calcium carbonate, calcium hydroxide, water reducing agent, β-cyclodextrin / complexing agent inclusion compound and PVA fiber into another bucket, and stir with an electric stirrer for 10 - 20 min to obtain the powder material;

[0098] c. Before use, slowly add the powder material into the liquid material, stirring while adding until a uniform and delicate slurry is stirred to obtain the self-healing polymer emulsion cement-based waterproof coating.

[0099] In this example, the preparation method of the polyurethane-modified acrylate copolymer emulsion containing diselenide bond and acylhydrazone bond includes the following steps:

[0100] 1) Prepare acrylate copolymer emulsion containing ketone carbonyl

[0101] ① Mix ethyl acrylate, vinyl acetate, methacrylic acid, 2-[(2-methyl-1-oxo-2-propenyl)oxy]ethyl 3-oxobutyrate evenly according to the mass ratio of 60:35:3:2 to make a mixed monomer;

[0102] ② Dissolve 0.15 g of emulsifier MS-1 in 120 g of deionized water, stir at 400 - 500 r / min for 30 min, add 100 g of mixed monomers, and continue stirring for 45 min to form a monomer pre-emulsion.

[0103] ③ Take 1 / 5 of the mass of the monomer pre-emulsion and 1 / 2 of the mass of the initiator (0.35 g of potassium persulfate) and add them to the reaction kettle. Heat up to 75 °C for initiation. When a blue phase appears in the system, add the remaining monomer pre-emulsion and the remaining initiator (0.35 g of potassium persulfate) dropwise to the reaction kettle, and control the dropping to be completed within 2 - 3 h.

[0104] ④ After the dropping is completed, heat up to 85 °C and keep warm for 35 min, cool to room temperature, neutralize with ammonia water to a pH value of 7 - 8, filter to obtain an acrylate copolymer emulsion containing a ketone carbonyl group.

[0105] 2) Preparation of 3,3'-diselenodipropionylhydrazide

[0106] ① Add 0.9 parts of 3,3'-diselenodipropionic acid, 14.2 parts of ethanol, 0.11 parts of methanesulfonic acid, and 14 parts of cyclohexane to a three-necked flask. Heat up to 110 °C and stir under reflux for water separation for 7 h. Rotate and evaporate to remove cyclohexane. Wash the remaining product with deionized water and Na2CO3 solution multiple times until the pH is neutral, and dry to obtain diethyl 3,3'-diselenodipropionate.

[0107] ② Add 0.6 parts of diethyl 3,3'-diselenodipropionate, 0.23 parts of hydrazine hydrate, and 23.7 parts of ethanol to a three-necked flask. Heat up to 90 °C and stir under reflux for 6 h. Cool to room temperature, then filter by suction. Wash the filter cake with deionized water multiple times, and then dry under vacuum to obtain 3,3'-diselenodipropionylhydrazide.

[0108] 3) Preparation of a hydrazide group-terminated polyurethane emulsion containing a diselenide bond

[0109] ① Polycaprolactone diol (relative molecular mass of 2000) is vacuum dehydrated at 120 °C for 3 h, and then added to a reaction kettle together with dimethylolpropionic acid and hexamethylene diisocyanate. Under nitrogen protection, heat up to 90 °C and stir for reaction for 3 h. After the reaction, add acetone to adjust the viscosity of the system to 1000 cp; among them, the molar ratio of the isocyanate group in hexamethylene diisocyanate to the hydroxyl group in polycaprolactone diol is 1.3:1, and the mass of dimethylolpropionic acid is 3% of the sum of the masses of polycaprolactone diol and hexamethylene diisocyanate.

[0110] ② Continuously add an equimolar amount of triethanolamine to the reaction kettle. After stirring for 30 min, cool down to 45 °C, then add deionized water in an amount twice the sum of the masses of polycaprolactone diol and hexamethylene diisocyanate, and 3,3'-diselenodipropionyl hydrazide accounting for 3% of the sum of the masses of polycaprolactone diol and hexamethylene diisocyanate. After stirring for 4 h, distill off acetone under reduced pressure at 45 °C for 4 h to obtain a hydrazide-terminated polyurethane emulsion containing diselenide bonds;

[0111] 4) Preparation of a polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and acylhydrazone bonds

[0112] Mix the hydrazide-terminated polyurethane emulsion containing diselenide bonds and the acrylate copolymer emulsion containing ketone carbonyl groups evenly in a mass ratio of 1:1.6 to obtain a polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and acylhydrazone bonds.

[0113] In this example, the preparation method of the β-cyclodextrin / complexing agent inclusion compound includes the following steps:

[0114] Mix 100 parts of β-cyclodextrin with 300 parts of deionized water evenly, then add 18 parts of dodecyltrimethylammonium chloride, heat to 75 °C and stir at 180 rpm for 25 min, then add 20 parts of sodium gluconate and 25 parts of sodium citrate, continue to stir at 75 °C at 250 rpm for 25 min, then perform ultrasonic dispersion treatment for 10 min, and finally carry out centrifugal spray drying on the mixed solution, controlling the inlet air temperature at 190 °C and the outlet air temperature at 85 °C to obtain a β-cyclodextrin / complexing agent inclusion compound with a particle size of 200 mesh and a moisture content of 1%.

[0115] Example 3

[0116] A self-healing polymer emulsion cement-based waterproof coating includes a liquid material and a powder material with a mass ratio of 1:1.5; the liquid material includes the following raw materials in parts by mass: 90 parts of a polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and acylhydrazone bonds, 2 parts of a defoaming agent, and 2 parts of a film-forming aid; the powder material includes the following raw materials in parts by mass: 45 parts of cement, 30 parts of stone powder, 15 parts of heavy calcium carbonate, 8 parts of calcium hydroxide, 1 part of a water reducer, 0.8 part of a β-cyclodextrin / complexing agent inclusion compound, and 0.16 part of PVA fiber.

[0117] In this example, the preparation method of the self-healing polymer emulsion cement-based waterproof coating includes the following steps:

[0118] a. Sequentially add the defoaming agent and the film-forming aid to the bucket, then add the polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and acylhydrazone bonds, and stir with an electric stirrer for 10 - 15 min to obtain the liquid material;

[0119] b. Add cement, stone powder, heavy calcium carbonate, calcium hydroxide, water reducing agent, β-cyclodextrin / complexing agent inclusion compound, and PVA fiber into another feed bucket, and stir with an electric stirrer for 10 - 20 min to obtain the powder material;

[0120] c. Before use, slowly add the powder material into the liquid material while stirring until a uniform and delicate slurry is formed to obtain the self-healing polymer emulsion cement-based waterproof coating.

[0121] In this example, the preparation method of the polyurethane-modified acrylate copolymer emulsion containing diselenide bond and acylhydrazone bond includes the following steps:

[0122] 1) Prepare the acrylate copolymer emulsion containing ketone carbonyl

[0123] ① Mix isobutyl acrylate, isobutyl methacrylate, methacrylic acid, and 2-

〔2-methyl-1-oxy-2-propenyl〕oxy

[0124] ② Dissolve 0.16 g of MS-1 type emulsifier in 140 g of deionized water, stir at 400 - 500 r / min for 30 min, add 100 g of the mixed monomer, and continue stirring for 55 min to form a monomer pre-emulsion;

[0125] ③ Take 1 / 5 of the mass of the monomer pre-emulsion and 3 / 5 of the mass of the initiator (0.48 g of potassium persulfate) and add them into the reaction kettle, heat up to 75 °C for initiation. When the system turns slightly blue, add the remaining monomer pre-emulsion and the remaining initiator (0.32 g of potassium persulfate) dropwise into the reaction kettle, and control the dropping to be completed within 2 - 3 h;

[0126] ④ After the dropping is completed, heat up to 90 °C and keep warm for 40 min, cool to room temperature, neutralize with ammonia water to a pH value of 7 - 8, and filter to obtain the acrylate copolymer emulsion containing ketone carbonyl;

[0127] 2) Prepare 3,3'-diselenodipropionylhydrazide

[0128] ① Add 0.5 part of 3,3'-diselenodipropionic acid, 8.6 parts of ethanol, 0.07 part of methanesulfonic acid, and 10.2 parts of cyclohexane into a three-necked flask, heat up to 105 °C, stir and reflux for water separation reaction for 7 h, rotary evaporate to remove cyclohexane, wash the remaining product with deionized water and Na2CO3 solution for multiple times until the pH is neutral, and dry to obtain diethyl 3,3'-diselenodipropionate;

[0129] ② Add 0.8 parts of diethyl 3,3'-diselenodipropionate, 0.3 parts of hydrazine hydrate and 31.6 parts of ethanol into a three-necked flask, heat up to 92 °C and stir under reflux for 5 h. After cooling to room temperature, filter by suction, wash the filter cake with deionized water for several times, and then dry it under vacuum to obtain 3,3'-diselenodipropionyl hydrazide;

[0130] 3) Prepare a hydrazide group-terminated polyurethane emulsion containing diselenide bonds

[0131] ① Polyethylene glycol adipate diol (with a relative molecular mass of 1000) is dehydrated under vacuum at 120 °C for 3 h, and then added into a reaction kettle together with dimethylolpropionic acid and toluene diisocyanate. Under nitrogen protection, heat up to 85 °C and stir for 4 h. After the reaction, add acetone to adjust the viscosity of the system to 1000 cp; among them, the molar ratio of the isocyanate group in toluene diisocyanate to the hydroxyl group in polyethylene glycol adipate diol is 1.5:1, and the mass of dimethylolpropionic acid is 5% of the sum of the masses of polyethylene glycol adipate diol and toluene diisocyanate;

[0132] ② Continuously add triethanolamine with an equimolar amount to dimethylolpropionic acid into the reaction kettle, stir for 30 min, then cool down to 55 °C, and then add deionized water twice the sum of the masses of polyethylene glycol adipate diol and toluene diisocyanate and 3,3'-diselenodipropionyl hydrazide accounting for 3% of the sum of the masses of polyethylene glycol adipate diol and toluene diisocyanate. After stirring for 4 h, distill off acetone under reduced pressure at 45 °C for 4 h to obtain a hydrazide group-terminated polyurethane emulsion containing diselenide bonds;

[0133] 4) Prepare a polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and acylhydrazone bonds

[0134] Mix the hydrazide group-terminated polyurethane emulsion containing diselenide bonds and the acrylate copolymer emulsion containing ketone carbonyl groups evenly according to a mass ratio of 1:1.8 to obtain a polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and acylhydrazone bonds.

[0135] In this example, the preparation method of the β-cyclodextrin / complexing agent inclusion complex includes the following steps:

[0136] Mix 100 parts of β-cyclodextrin evenly with 300 parts of deionized water, add 10 parts of dodecyltrimethylammonium chloride, heat to 80 °C and stir at a speed of 200 rpm for 30 min, then add 35 parts of sodium citrate, continue to stir at 80 °C at a speed of 300 rpm for 30 min, then perform ultrasonic dispersion treatment for 12 min, and finally perform centrifugal spray drying on the mixed solution, control the inlet air temperature at 180 °C, the exhaust air temperature at 80 °C, and discharge to obtain a β-cyclodextrin / complexing agent inclusion complex with a particle size of 300 mesh and a moisture content of 1%.

[0137] The physical properties of the self-healing polymer emulsion cement-based waterproof coatings in Examples 1 to 3 were tested. Among them, the tensile strength and elongation at break were tested in accordance with GB / T 23445-2009 "Polymer Cement Waterproof Coatings"; the bond strength and water impermeability were tested in accordance with GB / T 16777-2008 "Test Methods for Building Waterproof Coatings"; the test results were compared with the technical requirements specified in Type III of GB / T 23445-2009 "Polymer Cement Waterproof Coatings", and the results are shown in Table 1.

[0138] Table 1 Test Results of Physical Properties

[0139]

[0140] The self-healing test was carried out on the self-healing polymer emulsion cement-based waterproof coatings in Examples 1 to 3 to test their self-healing performance. The specific steps are as follows:

[0141] 1) Preparation of film specimens: Pour the polymer emulsion cement-based waterproof coating into a mold with an outer frame size of 33 cm × 36 cm, an inner frame size of 25 cm × 28 cm, and a thickness of 0.2 cm, so that the sample thickness reaches (1.5 ± 0.2) mm, and demold after standing for 96 h under standard conditions; then turn the demolded sample upside down and treat it in a drying oven at (40 ± 2) °C for 48 h, take it out and place it in a desiccator to cool to room temperature;

[0142] 2) Crack prefabrication and self-healing: Cut out 4 small film pieces with a size of 7 cm × 7 cm from the film with a paper cutter, and cut a fine crack with a width less than 0.10 mm in each of the 2 small film pieces, and cut a crack with a width between 0.10 and 0.3 mm in each of the other 2 small film pieces, and measure the initial crack width. Then place the film with fine cracks (≤0.10 mm) in a natural environment (23 ± 2 °C, RH 50 ± 10%) for curing, and measure the crack width every 4 h. Place the film with wider cracks (0.1 - 0.3 mm) in a humid environment (20 °C, RH 95%) for curing, and measure the crack width every 3 days.

[0143] Table 2 Test Results of Self-Healing Performance (Fine Cracks)

[0144]

[0145]

[0146] Table 3 Test Results of Self-Healing Performance (Wider Cracks)

[0147] Experimental group Curing for 0 d Curing for 3 d Curing for 6 d Curing for 9 d Curing for 12 d Curing for 15 d Curing for 18 d Example 1 0.12 mm 0.07 mm 0.02 mm 0.00 mm 0.00 mm 0.00 mm 0.00 mm Example 1 0.18 mm 0.11 mm 0.06 mm 0.02 mm 0.00 mm 0.00 mm 0.00 mm Example 2 0.17 mm 0.10 mm 0.05 mm 0.01 mm 0.00 mm 0.00 mm 0.00 mm Example 2 0.28 mm 0.20 mm 0.14 mm 0.09 mm 0.05 mm 0.02 mm 0.00 mm Example 3 0.13 mm 0.07 mm 0.03 mm 0.00 mm 0.00 mm 0.00 mm 0.00 mm Example 3 0.22 mm 0.15 mm 0.10 mm 0.06 mm 0.03 mm 0.00 mm 0.00 mm

[0148] From the above test results, it can be seen that the coating film formed by the self-healing polymer emulsion cement-based waterproof coating of the present invention has excellent mechanical properties. When cracks appear in the coating film, in the natural environment, based on the dual dynamic reversible recombination reactions of diselenide bonds and hydrazone bonds, the response can be quickly triggered to achieve perfect repair of microcracks, and the self-healing efficiency is greatly improved; in a humid environment, the β-cyclodextrin / complexing agent inclusion complex will slowly release the complexing agent in the form of ions and complex calcium ions, and react with CO3 2- to produce crystallization at the crack, maintaining the long-term effectiveness of the complexing agent for self-healing of the crack. Its synergistic effect with PVA fibers can achieve rapid self-healing of relatively wide cracks, effectively solving the problem of building leakage caused by cracks in the waterproof coating film due to external forces.

[0149] The above embodiments are merely examples clearly described and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here, and the obvious changes or modifications thus extended are still within the protection scope of the present invention.

Claims

1. A self-healing polymer emulsion cement-based waterproof coating, characterized in that, It includes a liquid material and a powder material with a mass ratio of 1:(1 - 1.5); the liquid material includes the following raw materials in parts by mass: 90 - 96 parts of a polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and hydrazone bonds, 1 - 3 parts of an antifoaming agent, and 1 - 3 parts of a film-forming aid; the powder material includes the following raw materials in parts by mass: 40 - 50 parts of cement, 25 - 45 parts of stone powder, 10 - 20 parts of heavy calcium carbonate, 3 - 8 parts of calcium hydroxide, 0.3 - 1 part of a water-reducing agent, 0.2 - 1.2 parts of a β-cyclodextrin / complexing agent inclusion compound, and 0.08 - 0.32 parts of PVA fiber; The preparation method of the β-cyclodextrin / complexing agent inclusion compound is as follows: After mixing β-cyclodextrin with water evenly, add dodecyl trimethyl ammonium chloride and heat with stirring, then add the complexing agent and continue heating with stirring, followed by ultrasonic dispersion treatment, and finally perform centrifugal spray drying on the mixed solution to obtain the β-cyclodextrin / complexing agent inclusion compound; the complexing agent complexes with calcium ions in the coating.

2. The self-healing polymer emulsion cement-based waterproof coating according to claim 1, characterized in that The polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and hydrazone bonds is formed by mixing a hydrazide-terminated polyurethane emulsion containing diselenide bonds and an acrylate copolymer emulsion containing ketone carbonyl groups in a mass ratio of 1:(1.5 - 2).

3. The self-healing polymer emulsion cement-based waterproof coating according to claim 2, wherein The preparation method of the hydrazide-terminated polyurethane emulsion containing diselenide bonds is as follows: 1) After dehydrating the polyester diol monomer, add it, dimethylolpropionic acid, and the diisocyanate monomer into a reaction kettle. Under nitrogen protection, raise the temperature to 70 - 90 °C and stir for 2 - 4 h. After the reaction, add an organic solvent to adjust the viscosity of the system to 600 - 1300 cp; 2) Continue to add triethanolamine to the reaction kettle, stir for 15 - 30 min, then cool to 40 - 55 °C, and then add water and 3,3'-diselenodipropionyl hydrazide, and continue to stir for 2 - 4 h. Remove the organic solvent to obtain the hydrazide-terminated polyurethane emulsion containing diselenide bonds.

4. The self-healing polymer emulsion cement-based waterproof coating according to claim 3, wherein, The preparation method of the 3,3'-diselenodipropionyl hydrazide is as follows: ① Add 3,3'-diselenodipropionic acid, ethanol, methanesulfonic acid, and cyclohexane into a three-necked flask, raise the temperature for stirring and refluxing for water separation reaction. After the reaction, distill off cyclohexane, wash the remaining product until the pH is neutral, and dry to obtain diethyl 3,3'-diselenodipropionate; ② Add diethyl 3,3'-diselenodipropionate, hydrazine hydrate, and ethanol into a three-necked flask, raise the temperature for stirring and refluxing reaction. After the reaction ends, wait for the reaction solution to cool to room temperature and perform suction filtration. Wash and dry the solid to obtain 3,3'-diselenodipropionyl hydrazide.

5. The self-healing polymer emulsion cement-based waterproof coating according to claim 4, wherein The mass parts of each raw material in step ① are: 0.3 - 1 part of 3,3'-diselenodipropionic acid, 7.9 - 15.8 parts of ethanol, 0.05 - 0.12 part of methanesulfonic acid, and 9.4 - 15.6 parts of cyclohexane; the mass parts of each raw material in step ② are: 0.4 - 0.8 part of diethyl 3,3'-diselenodipropionate, 0.1 - 0.3 part of hydrazine hydrate, and 15.8 - 31.6 parts of ethanol.

6. The self-healing polymer emulsion cement-based waterproof coating according to claim 4, characterized in that, The reaction temperature of the stirring and refluxing for water separation reaction in step ① is 100 - 110 °C, and the reaction time is 6 - 8 h; the reaction temperature of the stirring and refluxing reaction in step ② is 90 - 95 °C, and the reaction time is 5 - 6 h.

7. The self-healing polymer emulsion cement-based waterproof coating according to claim 1, characterized in that, The preparation method of the β-cyclodextrin / complexing agent inclusion complex is as follows: After mixing β-cyclodextrin and water evenly, add dodecyl trimethyl ammonium chloride, heat to 70-80 °C and stir for 20-30 min, then add the complexing agent, continue to stir at 70-80 °C for 20-30 min, then perform ultrasonic dispersion treatment for 10-15 min, and finally carry out centrifugal spray drying on the mixed solution to obtain the β-cyclodextrin / complexing agent inclusion complex.

8. The self-healing polymer emulsion cement-based waterproof coating according to claim 7, characterized in that, During the preparation process of the β-cyclodextrin / complexing agent inclusion complex, the mass parts of each raw material are as follows: 100 parts of β-cyclodextrin, 200-300 parts of water, 10-20 parts of dodecyl trimethyl ammonium chloride, and 30-50 parts of complexing agent.

9. The self-healing polymer emulsion cement-based waterproof coating according to claim 1, characterized in that, The length of the PVA fiber is 3-5 mm, and the diameter is 12-18 μm; the particle size of the β-cyclodextrin / complexing agent inclusion complex is 200-300 mesh, and the moisture content is ≤2%; the defoaming agent is an organosilicon defoaming agent; the film-forming aid is an alcohol-based film-forming aid; the cement is ordinary Portland cement; the stone powder is granite stone powder; the water reducing agent is a polycarboxylate superplasticizer, and the water reducing rate is 15-25%.

10. A preparation method of a self-healing polymer emulsion cement-based waterproof coating according to any one of claims 1-9, comprising the following steps: a. Sequentially add the defoaming agent and the film-forming aid into a feed tank, then add the polyurethane-modified acrylate copolymer emulsion containing diselenide bonds and hydrazone bonds, and stir evenly to obtain the liquid material. b. Add cement, stone powder, heavy calcium carbonate, calcium hydroxide, water reducing agent, β-cyclodextrin / complexing agent inclusion complex and PVA fiber into another feed tank, and stir evenly to obtain the powder material. c. Before use, slowly add the powder material into the liquid material, and stir while adding until a uniform and delicate slurry is stirred to obtain the self-healing polymer emulsion cement-based waterproof coating.

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