Self-repairing exterior wall waterproof coating and preparation method thereof

Abstract

The invention provides a self-repairing exterior wall waterproof coating and a preparation method thereof.The self-repairing exterior wall waterproof coating is prepared from, by weight, 1%-15% of low-calcium aluminate cement, 1%-5% of silicon dioxide, 0.1%-0.5% of bactericide, 0.1%-0.5% of defoaming agent, 0.1%-0.5% of composition A and the balance deionized water. The composition A comprises lauryl sodium sulfate, sodium dodecyl benzene sulfonate and lauryl polyoxyethylene ether sodium sulfate, the defoaming agent accounts for 0.5%-1%, the composition A accounts for 0.5%-1.5%, the composition B accounts for 15%-50%, and the balance is deionized water, the composition A comprises lauryl sodium sulfate, sodium dodecyl benzene sulfonate and lauryl polyoxyethylene ether sodium sulfate, and the defoaming agent accounts for 0.5%-1.5%. The composition A comprises lauryl sodium sulfate, sodium dodecyl benzene sulfonate and lauryl polyoxyethylene ether sodium sulfate, the ratio of the lauryl sodium sulfate to the sodium dodecyl benzene sulfonate to the lauryl polyoxyethylene ether sodium sulfate is 1: 0.8-1: 0.8-1, the composition B comprises polyvinyl acetate resin, propylene carbonate, dioctyl sebacate and a waterproof agent, and the ratio of the polyvinyl acetate resin to the propylene carbonate to the dioctyl sebacate to the waterproof agent is 1: 0.2-0.4: 0.6-0.8: 0.1-0.2.

Description

Technical Field

[0001] This application relates to the field of building technology, and specifically, to a self-healing exterior wall waterproof coating and a preparation method thereof. Background Art

[0002] In recent years, urban construction has developed by leaps and bounds. As the reinforced concrete structure mainly used in urban buildings, the market has put forward higher requirements, such as the waterproofing problem of the reinforced concrete structure. In related technologies, there are various waterproofing methods for reinforced concrete structures. The more common way is to apply a waterproof coating on the outer surface of the reinforced concrete structure. However, in actual use, the differences in building materials, the building construction process, and the environment where the building is located will all affect the use effect of the waterproof coating, such as the construction problem in a low-temperature environment. Moreover, generally speaking, reinforced concrete is a non-homogeneous porous material. During the construction process, due to internal stress, construction temperature, and other reasons, damage to the internal structure will occur, resulting in the appearance of cracks, seriously affecting the waterproof effect of the outer waterproof coating.

[0003] Therefore, there is an urgent need in this field for a self-healing exterior wall waterproof coating and a preparation method thereof to solve the aforementioned problems. Summary of the Invention

[0004] The purpose of this application is to provide a self-healing exterior wall waterproof coating and a preparation method thereof to solve at least one of the technical problems described in the background art.

[0005] Specifically, in the first aspect of this application, a self-healing exterior wall waterproof coating is provided, which includes low-calcium aluminate cement, silica, a bactericide, an antifoaming agent, composition A, and composition B. By weight, the proportion of low-calcium aluminate cement is 1% - 15%, the proportion of silica is 1% - 5%, the proportion of the bactericide is 0.1% - 0.5%, the proportion of the antifoaming agent is 0.5% - 1%, the proportion of composition A is 0.5% - 1.5%, the proportion of composition B is 15% - 50%, and the balance is deionized water.

[0006] Among them, composition A includes sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium dodecyl polyoxyethylene ether sulfate, and the ratio of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium dodecyl polyoxyethylene ether sulfate is 1:0.8 - 1:0.8 - 1. Composition B includes polyvinyl acetate resin, propylene carbonate, dioctyl sebacate, and a waterproofing agent, and the ratio of polyvinyl acetate resin, propylene carbonate, dioctyl sebacate, and the waterproofing agent is 1:0.2 - 0.4:0.6 - 0.8:0.1 - 0.2.

[0007] Adopting the above - mentioned scheme, by setting low - calcium aluminate cement and silica, it can provide the physical and chemical properties for the coating to fit and smear on the surface, improve the homogeneity of the material after the coating is smeared, and further reduce the occurrence of delamination cracks. Secondly, by using Composition B, a polyvinyl acetate resin film can be formed on the surface of low - calcium aluminate cement and silica, improving the overall adhesion and flexibility of the coating. Also, when external water seeps into the coating layer after the waterproofing fails, a hydration reaction occurs, forming solid insoluble substances such as calcium aluminate hydrate, aluminum hydroxide, and C - S - H (Calcium Silicate Hydrate) gel to fill the coating cracks and automatically repair the cracked parts. Thirdly, by using Composition A, it can effectively improve the particle dispersibility of the coating, make the coating more homogeneous, improve the impermeability, and the synergy between Composition A and Composition B can also effectively improve the low - temperature resistance of the coating and improve the use effect of the coating in low - temperature environments.

[0008] In some alternative embodiments of the present application, the waterproofing agent includes at least one of acrylic resin and methyl silicone resin.

[0009] In some alternative embodiments of the present application, the defoaming agent uses an organosilicon defoaming agent.

[0010] In some alternative embodiments of the present application, the waterproofing agent includes phenyl silicone resin and methyl silicone resin. By weight, the ratio of phenyl silicone resin to methyl silicone resin is 1:2 - 3.

[0011] Adopting the above - mentioned scheme, by using a waterproofing agent with specific components and proportion ranges, the waterproof property and adhesion effect of the obtained coating in low - temperature environments can be improved.

[0012] In some alternative embodiments of the present application, by weight, the ratio of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and sodium dodecyl polyoxyethylene ether sulfate is 1:0.8:1.

[0013] Adopting the above - mentioned scheme, by using Composition A within a specific proportion range, the particle dispersibility of the coating is further improved, making the coating more homogeneous, and it can also effectively synergize with Composition B to significantly improve the low - temperature resistance of the coating and improve the use effect of the coating in low - temperature environments.

[0014] In some alternative embodiments of the present application, by weight, the ratio of polyvinyl acetate resin, propylene carbonate, dioctyl sebacate, and the waterproofing agent is 1:0.3:0.7:0.2.

[0015] Adopting the above - mentioned scheme, by using Composition B within a specific proportion range, it can improve particle dispersibility and form a polymer film, improve the fluidity of the slurry and interfacial properties, improve the homogeneity of the coating, and can also promote the progress of the hydration reaction and self - repair after cracks occur.

[0016] In some alternative embodiments of the present application, the self-healing exterior wall waterproof coating further includes an auxiliary agent. By weight, the proportion of the auxiliary agent is 1%-2%. The auxiliary agent includes polyethylene oxide, sodium tetraborate, and styrene-acrylate emulsion with a monomer mass percentage of 40%. The ratio of polyethylene oxide, sodium tetraborate, and styrene-acrylate emulsion is 1:0.1-0.2:0.5-1.

[0017] With the above solution, by using an auxiliary agent with specific components and proportion ranges, it can effectively cooperate with Composition A and Composition B to improve the adhesiveness and film-forming property of the coating.

[0018] In some alternative embodiments of the present application, by weight, the proportion of low-calcium aluminate cement is 8%, the proportion of silicon dioxide is 2%, the proportion of bactericide is 0.3%, the proportion of defoamer is 0.8%, the proportion of Composition A is 1%, the proportion of Composition B is 40%, the proportion of auxiliary agent is 1%, and the balance is deionized water.

[0019] In some alternative embodiments of the present application, the bactericide includes at least one of cuprous oxide and copper hydroxide.

[0020] Specifically, in the second aspect of the present application, a preparation method of a self-healing exterior wall waterproof coating is provided, which is characterized by including the following steps:

[0021] Add the corresponding amounts of low-calcium aluminate cement, silicon dioxide, Composition A, Composition B, defoamer, and bactericide to deionized water in sequence. For each added component, stir and dissolve it evenly before adding the next component.

[0022] In some alternative embodiments of the present application, the preparation method of the self-healing exterior wall waterproof coating further includes a step of adding the corresponding amount of auxiliary agent after adding Composition B and before adding the defoamer.

[0023] In some alternative embodiments of the present application, in the preparation method of the self-healing exterior wall waterproof coating, the temperature needs to be controlled at room temperature and ultrasonic oscillation is performed for each added component.

[0024] In summary, the present application provides a self-healing exterior wall waterproof coating and a preparation method thereof. First, by setting low-calcium aluminate cement and silica, the coating can be provided with physical and chemical properties that fit and coat the surface, improving the material uniformity after coating, and thus reducing the occurrence of delamination cracks. Second, by using Composition B, a polyvinyl acetate resin film can be formed on the surface of the low-calcium aluminate cement and silica, improving the overall adhesion and flexibility of the coating. Also, when water seeps into the coating layer after waterproof failure, a hydration reaction occurs to form solid insoluble substances to fill the coating cracks, such as calcium aluminate hydrate, aluminum hydroxide, and C-S-H (Calcium Silicate Hydrate) gel, etc., automatically repairing the cracked parts. Third, by using Composition A, the particle dispersibility of the coating can be effectively improved, making the coating more uniform, improving the impermeability, and also effectively improving the low-temperature resistance of the coating, enhancing the use effect of the coating in low-temperature environments. Detailed Description of the Embodiments

[0025] Here, the exemplary embodiments will be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0026] The terms used in the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "the", and "said" used in the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0027] The present application will be described in detail below through embodiments.

[0028] Example 1

[0029] Preparation of a self-healing exterior wall waterproof coating:

[0030] Add deionized water into the reaction vessel.

[0031] Add low-calcium aluminate cement into the vessel, so that the mass percentage of the low-calcium aluminate cement is 1%, control the temperature in the vessel at 25°C, and use ultrasonic vibration to stir evenly.

[0032] Add silica into the vessel, so that the mass percentage of the silica is 1%, control the temperature in the vessel at 25°C, and use ultrasonic vibration to stir evenly.

[0033] Add composition A to the container so that the mass percentage of composition A is 0.5%, control the temperature inside the container at 25°C, and use ultrasonic oscillation to stir evenly. By weight, the ratio of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium dodecyl polyoxyethylene ether sulfate in composition A is 1:0.8:1.

[0034] Add composition B to the container so that the mass percentage of composition B is 15%, control the temperature inside the container at 25°C, and use ultrasonic oscillation to stir evenly. By weight, the ratio of polyvinyl acetate resin, propylene carbonate, dioctyl sebacate, and waterproofing agent in composition B is 1:0.3:0.7:0.2, and the waterproofing agent is acrylic resin.

[0035] Add defoamer to the container so that the mass percentage of defoamer is 0.5%, control the temperature inside the container at 25°C, and use ultrasonic oscillation to stir evenly.

[0036] Add bactericide to the container so that the mass percentage of bactericide is 0.1%, and use ultrasonic oscillation to stir evenly to obtain the waterproof coating.

[0037] Example 2

[0038] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 1, except that in this example, the mass percentage of low-calcium aluminate cement used is 5%, and the mass percentage of silica used is 3%.

[0039] Example 3

[0040] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 1, except that in this example, the mass percentage of low-calcium aluminate cement used is 10%, the mass percentage of silica used is 3%, and the mass percentage of composition B used is 35%.

[0041] Example 4

[0042] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 1, except that in this example, the mass percentage of low-calcium aluminate cement used is 15%, the mass percentage of silica used is 5%, and the mass percentage of composition B used is 50%.

[0043] Example 5

[0044] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 1, except that in this example, the mass percentage of low-calcium aluminate cement used is 6%, the mass percentage of silica used is 2%, and the mass percentage of composition B used is 40%.

[0045] Example 6

[0046] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 5, except that the mass percentage of Composition A used in this example is 1%.

[0047] Example 7

[0048] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 5, except that the mass percentage of Composition A used in this example is 1.5%.

[0049] Example 8

[0050] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 6, except that the mass percentage of the defoamer used in this example is 0.8% and the mass percentage of the bactericide used is 0.3%.

[0051] Example 9

[0052] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 8, except that by weight, the ratio of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium dodecyl polyoxyethylene ether sulfate in Composition A is 1:0.8:0.8, and by weight, the ratio of polyvinyl acetate resin, propylene carbonate, dioctyl sebacate, and waterproofing agent in Composition B is 1:0.2:0.6:0.1.

[0053] Example 10

[0054] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 8, except that by weight, the ratio of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium dodecyl polyoxyethylene ether sulfate in Composition A is 1:0.9:0.9, and by weight, the ratio of polyvinyl acetate resin, propylene carbonate, dioctyl sebacate, and waterproofing agent in Composition B is 1:0.3:0.7:0.1.

[0055] Example 11

[0056] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 8, except that by weight, the ratio of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium dodecyl polyoxyethylene ether sulfate in Composition A is 1:1:1, and by weight, the ratio of polyvinyl acetate resin, propylene carbonate, dioctyl sebacate, and waterproofing agent in Composition B is 1:0.4:0.8:0.2.

[0057] Example 12

[0058] The waterproof coatings obtained in Examples 1 to 11 were tested using the test methods in GB / T 23445-2009 Building Waterproof Coatings to obtain low-temperature flexibility and bond strength. The test results are shown in Table 1.

[0059] Table 1 Influence of different ratios on the waterproof coating

[0060]

[0061]

[0062] As can be seen from Table 1, the waterproof coatings provided by this application with the given ratios and components have excellent low-temperature performance and bond strength, can meet the usage requirements, and under the ratio provided in Example 8, the obtained waterproof coating has the best low-temperature flexibility and bond strength.

[0063] Example 13

[0064] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 8, except that the waterproofing agent includes acrylic resin and methyl silicone resin, and by weight, the ratio of acrylic resin to methyl silicone resin in the waterproofing agent is 1:0.1.

[0065] Example 14

[0066] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 8, except that the waterproofing agent includes acrylic resin and methyl silicone resin, and by weight, the ratio of acrylic resin to methyl silicone resin in the waterproofing agent is 1:0.2.

[0067] Example 15

[0068] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 8, except that the waterproofing agent includes acrylic resin and methyl silicone resin, and by weight, the ratio of acrylic resin to methyl silicone resin in the waterproofing agent is 1:0.3.

[0069] Example 16

[0070] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 8, except that the waterproofing agent includes acrylic resin and methyl silicone resin, and by weight, the ratio of acrylic resin to methyl silicone resin in the waterproofing agent is 1:0.4.

[0071] Example 17

[0072] The low-temperature flexibility test method in GB / T 23445-2009 Building Waterproof Coatings was used to detect the waterproof coatings obtained in Example 8 and Examples 13 to 16, and the low-temperature flexibility was obtained. The freeze-thaw cycle resistance determination method in GB / T 9268-2008 was used, with the freeze-thaw cycle temperature ranging from -20°C to 23°C and the number of cycles being 10 times. The test results are shown in Table 2.

[0073] Table 2 Influence of different waterproofing agent ratios on waterproof coatings

[0074]

[0075] As can be seen from Table 2, when only acrylic resin is used in this application, the obtained waterproof coating has better low-temperature use effect. However, when using the acrylic resin and methyl silicone resin with the ratios provided in this application, it has the best low-temperature performance.

[0076] Example 18

[0077] Preparation of a self-healing exterior wall waterproof coating:

[0078] Add deionized water to the reaction vessel.

[0079] Add low-calcium aluminate cement to the vessel, with the mass percentage of low-calcium aluminate cement being 6%, and control the temperature in the vessel at 25°C. Use ultrasonic oscillation to stir evenly.

[0080] Add silicon dioxide to the vessel, with the mass percentage of silicon dioxide being 2%, and control the temperature in the vessel at 25°C. Use ultrasonic oscillation to stir evenly.

[0081] Add Composition A to the vessel, with the mass percentage of Composition A being 1%, and control the temperature in the vessel at 25°C. Use ultrasonic oscillation to stir evenly. By weight, the ratio of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and sodium dodecyl polyoxyethylene ether sulfate in Composition A is 1:0.8:1.

[0082] Add Composition B to the vessel, with the mass percentage of Composition B being 40%, and control the temperature in the vessel at 25°C. Use ultrasonic oscillation to stir evenly. By weight, the ratio of polyvinyl acetate resin, propylene carbonate, dioctyl sebacate, and waterproofing agent in Composition B is 1:0.3:0.7:0.2. The waterproofing agent includes acrylic resin and methyl silicone resin, and the ratio of acrylic resin to methyl silicone resin in the waterproofing agent is 1:0.2.

[0083] Add additives to the container so that the mass percentage of the additives is 1%, control the temperature in the container at 25°C, and use ultrasonic oscillation to stir evenly. The additives include polyethylene oxide, sodium tetraborate, and styrene-acrylate emulsion with a monomer mass percentage of 40%. The ratio of polyethylene oxide, sodium tetraborate, and styrene-acrylate emulsion is 1:0.1:0.5.

[0084] Add defoamer to the container so that the mass percentage of the defoamer is 0.8%, control the temperature in the container at 25°C, and use ultrasonic oscillation to stir evenly.

[0085] Add fungicide to the container so that the mass percentage of the fungicide is 0.3%, and use ultrasonic oscillation to stir evenly to obtain a waterproof coating.

[0086] Example 19

[0087] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 18, except that the ratio of polyethylene oxide, sodium tetraborate, and styrene-acrylate emulsion is 1:0.2:0.8.

[0088] Example 20

[0089] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 18, except that the ratio of polyethylene oxide, sodium tetraborate, and styrene-acrylate emulsion is 1:0.2:1.

[0090] Example 21

[0091] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 19, except that the mass percentage of the additives used in this example is 1.5%.

[0092] Example 22

[0093] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 19, except that the mass percentage of the additives used in this example is 2%.

[0094] Example 23

[0095] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 21, except that the additive used in this example is polyethylene oxide.

[0096] Example 24

[0097] Preparation of a self-healing exterior wall waterproof coating: The preparation process of this example is generally the same as that of Example 21, except that the auxiliary agent used in this example is styrene-acrylate emulsion.

[0098] Example 25

[0099] The waterproof coatings obtained in Examples 18 to 24 were tested using the test methods in GB / T 23445-2009 Building Waterproof Coatings to obtain low-temperature flexibility and bond strength. The test results are shown in Table 3.

[0100] Table 3 Influence of Auxiliary Agents with Different Proportions on Waterproof Coatings

[0101]

[0102] As can be seen from Table 3, the auxiliary agent provided by this application with the given proportion and components can significantly improve the bond strength of the obtained waterproof coating. And when using a single component of the auxiliary agent alone, the improvement of the bond strength of the obtained waterproof coating is not obvious. Therefore, there is a synergistic effect among multiple components of the auxiliary agent provided by this application, thereby improving the properties of the obtained waterproof coating. And under the proportion provided in Example 21, the obtained waterproof coating has the optimal low-temperature flexibility and bond strength.

[0103] In summary, this application provides a self-healing exterior wall waterproof coating and its preparation method. First, by setting low-calcium aluminate cement and silica, it can provide the physical and chemical properties for the coating to adhere to and coat the surface, improve the homogeneity of the material after coating, and thus reduce the occurrence of delamination cracks. Second, by using Composition B, a polyvinyl acetate resin film can be formed on the surface of low-calcium aluminate cement and silica, improving the overall adhesion and flexibility of the coating. Also, when water seeps into the coating layer after waterproof failure, a hydration reaction occurs to form solid insoluble substances to fill the coating cracks, such as calcium aluminate hydrate, aluminum hydroxide, and C-S-H (Calcium Silicate Hydrate) gel, etc., automatically repairing the cracked parts. Third, by using Composition A, it can effectively improve the particle dispersion of the coating, make the coating more homogeneous, improve the impermeability, and also effectively improve the low-temperature resistance of the coating, improving the use effect of the coating in low-temperature environments.

[0104] It should be noted that for those of ordinary skill in the art, the technical features in the above embodiments can be freely combined, and the formed technical solutions also belong to the disclosed embodiments of this application.

[0105] Furthermore, without departing from the principle of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A self-repairing exterior wall waterproof coating, characterized in that: The self-repairing exterior wall waterproof coating comprises low-calcium aluminate cement, silicon dioxide, a fungicide, a defoamer, a composition A and a composition B. By weight, the low-calcium aluminate cement accounts for 1%-15%, the silicon dioxide accounts for 1%-5%, the fungicide accounts for 0.1%-0.5%, the defoamer accounts for 0.5%-1%, the composition A accounts for 0.5%-1.5%, the composition B accounts for 15%-50%, and the balance is deionized water. Among them, the composition A includes sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and sodium dodecyl polyoxyethylene ether sulfate, and the ratio of the sodium dodecyl sulfate, the sodium dodecylbenzene sulfonate and the sodium dodecyl polyoxyethylene ether sulfate is 1:0.8-1:0.8-1. The composition B includes polyvinyl acetate resin, propylene carbonate, dioctyl sebacate and a waterproofing agent, and the ratio of the polyvinyl acetate resin, the propylene carbonate, the dioctyl sebacate and the waterproofing agent is 1:0.2-0.4:0.6-0.8:0.1-0.

2.

2. The self-repairing exterior wall waterproof coating according to claim 1, characterized in that: The waterproofing agent includes at least one of acrylic resin and methyl silicone resin.

3. The self-repairing exterior wall waterproof coating according to claim 2, characterized in that: The waterproofing agent comprises acrylic resin and methyl silicone resin, and the ratio of the acrylic resin to the methyl silicone resin is 1:0.2-0.3 by weight.

4. The self-repairing exterior wall waterproof coating according to claim 1, characterized in that: By weight, the ratio of the sodium dodecyl sulfate, the sodium dodecylbenzene sulfonate and the sodium dodecyl polyoxyethylene ether sulfate is 1:0.8:

1.

5. The self-repairing exterior wall waterproof coating according to claim 1, characterized in that: By weight, the ratio of the polyvinyl acetate resin, the propylene carbonate, the dioctyl sebacate and the waterproofing agent is 1:0.3:0.7:0.

2.

6. The self-repairing exterior wall waterproof coating according to claim 1, characterized in that: The self-repairing exterior wall waterproof coating also includes an additive, which accounts for 1%-2% by weight. The additive includes polyethylene oxide, sodium tetraborate and 40% styrene-acrylate emulsion of monomer mass percentage. The ratio of polyethylene oxide, sodium tetraborate and styrene-acrylate emulsion is 1:0.1-0.2:0.5-1.

7. The self-repairing exterior wall waterproof coating according to claim 6, characterized in that: By weight, the low-calcium aluminate cement accounts for 8%, the silicon dioxide accounts for 2%, the bactericide accounts for 0.3%, the defoamer accounts for 0.8%, the composition A accounts for 1%, the composition B accounts for 40%, the auxiliary agent accounts for 1%, and the balance is deionized water.

8. The self-repairing exterior wall waterproof coating according to claim 6, characterized in that: The bactericide includes at least one of cuprous oxide and cupric hydroxide.

9. A method for preparing a self-repairing exterior wall waterproof coating, characterized in that: The following steps are involved: Add corresponding amounts of low calcium aluminate cement, silicon dioxide, composition A, composition B, defoamer and bactericide to deionized water in sequence. Each time a component is added, stir and dissolve evenly before adding the next component.

10. The method for preparing the self-repairing exterior wall waterproof coating according to claim 9, characterized in that: The method further comprises the step of adding a corresponding amount of an auxiliary agent after adding the composition B and before adding the defoaming agent.

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