Self-healing emulsified asphalt waterproof coating and preparation method thereof

Abstract

The present application relates to waterproof coating technical field, especially to a kind of self-healing emulsified asphalt waterproof coating and preparation method thereof.The waterproof coating of the present application includes the following weight parts of raw materials: including the following weight parts of raw materials: aromatic hydrocarbon oil 5-10 parts, butyl rubber-gaft-4,4'-dithiodiamine 4-8 parts, asphalt 20-35 parts, emulsifier 4-8 parts, water 30-50 parts, powder 10-20 parts and butyl rubber emulsion 1-3.The self-healing emulsified asphalt waterproof coating of the present application introduces butyl rubber-gaft-4,4'-dithiodiamine, a key modified component, and optimizes the amount ratio between each raw material, realizes excellent self-healing function, significantly improved low-temperature flexibility and enhanced bonding performance.

Description

Technical Field

[0001] This invention relates to the field of waterproof coating technology, and in particular to a self-healing emulsified bitumen waterproof coating and its preparation method. Background Technology

[0002] Water-based waterproof coatings are an environmentally friendly material that uses water as a solvent and contains almost no harmful volatile organic compounds. They are extremely friendly to the environment and human health during construction and use, effectively avoiding the pollution and harm that may be caused by traditional solvent-based coatings.

[0003] Water-based waterproof coatings are divided into emulsified bitumen systems and acrylic emulsion systems. Emulsified bitumen waterproof coatings achieve better adhesion and waterproofing performance by emulsifying bitumen with water and adding different modifiers. Acrylic emulsion waterproof coatings, on the other hand, add appropriate modifiers to acrylic emulsions to improve their performance and application. The main advantages of emulsified bitumen systems over acrylic emulsion systems are lower cost and greater adaptability to different applications, making them more suitable for use in humid environments and large-area waterproofing projects. They are particularly cost-effective in scenarios where weather resistance requirements are not high, thus gaining widespread application.

[0004] However, emulsified bitumen waterproofing coatings, due to the water sensitivity of bitumen, exhibit poor adhesion upon contact with water, especially on damp surfaces, and are prone to becoming brittle and cracking at low temperatures. Furthermore, their modifiers generally have poor compatibility with acrylic or styrene-butadiene emulsion systems and exhibit poor adhesion to bitumen waterproofing membranes, easily leading to water seepage. In addition, most waterproofing coatings cannot self-repair after physical damage, requiring re-application of the waterproofing solution to restore its waterproofing function. Summary of the Invention

[0005] This invention provides a self-healing emulsified asphalt waterproof coating and its preparation method, which solves the problems of poor adhesion, poor low-temperature flexibility and lack of self-healing ability in existing water-based emulsified asphalt waterproof coatings.

[0006] According to a first aspect of the present invention, the present invention provides a self-healing emulsified asphalt waterproof coating, comprising the following raw materials in parts by weight: 5-10 parts of aromatic oil, 4-8 parts of styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine, 20-35 parts of asphalt, 4-8 parts of emulsifier, 30-50 parts of water, 10-20 parts of powder, and 1-3 parts of styrene-butadiene rubber emulsion.

[0007] This invention discloses a self-healing emulsified asphalt waterproof coating. Styrene-butadiene rubber (SBR)-graft-4,4'-dithiodiphenylamine (DPP) is used as the core modifying component, forming a highly efficient synergistic effect with other components such as aromatic oil, SBR emulsion, and cationic emulsifier. This synergistic effect not only improves the waterproof performance of the coating but also effectively solves the problems of poor adhesion, poor low-temperature flexibility, and lack of self-healing ability found in existing emulsified asphalt waterproof coatings. The active groups of SBR-graft-4,4'-dithiodiphenylamine can automatically recombine after physical damage, repairing defects and restoring waterproof function. Simultaneously, the rubber component in the SBR emulsion can fill the tiny gaps at the damaged area, further enhancing the self-healing effect. This self-healing ability significantly reduces the risk of leakage caused by localized damage, extends the service life of the waterproof layer, and reduces maintenance costs. Due to its excellent hydrophobic properties and chemical stability, SBR-graft-4,4'-dithiodiphenylamine also significantly enhances the coating's adhesion to damp substrates, maintaining excellent waterproof performance even in high humidity environments. Meanwhile, the addition of aromatic oil further enhances the coating's flexibility and water resistance, forming a synergistic effect with styrene-butadiene rubber (SBR)-graft-4,4'-dithiodiphenylamine (DPP) to jointly construct the coating's waterproof barrier, ensuring the long-lasting and stable waterproofing effect. Furthermore, the coating of this invention significantly improves low-temperature flexibility through the toughening effect of SBR-graft-4,4'-dithiodiphenylamine. This component can absorb stress at low temperatures, preventing crack propagation, while the synergistic toughening effect of the SBR emulsion further enhances the coating's impact resistance. This unique formulation design allows the coating to maintain good flexibility and waterproofing performance in cold environments, effectively preventing waterproofing failure due to low temperatures. The active groups in SBR-graft-4,4'-dithiodiphenylamine can form strong chemical bonds with the surface of the roll material, while the cationic emulsifier further enhances the adhesion strength between the coating and the substrate through electrostatic adsorption. This dual-action mechanism not only improves adhesion performance but also effectively prevents water seepage, ensuring the overall reliability of the waterproofing system.

[0008] Styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine represents a grafted product of styrene-butadiene rubber, whose molecular structure consists of 4,4'-dithiodiphenylamine structural units grafted onto the styrene-butadiene rubber chain via chemical bonds.

[0009] The ratio of 4,4'-dithiodiphenylamine to the main chain directly affects the molecular structure and performance of styrene-butadiene rubber (SBR)-graft-4,4'-dithiodiphenylamine. Furthermore, in the SBR-graft-4,4'-dithiodiphenylamine, the weight ratio of the graft (4,4'-dithiodiphenylamine) to the main chain (SBR) is (0.5-1):10. By precisely controlling this ratio, key performance indicators such as the self-healing speed, self-healing effect, low-temperature flexibility, and adhesive strength of the coating can be optimized to achieve an optimal balance.

[0010] Preferably, in the styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine, the weight ratio of the grafted material to the main chain is (0.8-0.9):10.

[0011] Furthermore, the preparation method of the styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine is as follows:

[0012] Step S1: Dissolve styrene-butadiene rubber in a solvent, add formic acid, control the temperature at 30-40℃, add hydrogen peroxide, stir the reaction for 8-10 hours, and then add anhydrous ethanol to obtain the precipitate of styrene-butadiene rubber epoxidation product.

[0013] Step S2: Wash the precipitate of styrene-butadiene rubber epoxidation product and dry it to obtain epoxy styrene-butadiene rubber;

[0014] Step S3: Dissolve epoxy styrene-butadiene rubber and 4,4'-dithiodiphenylamine in cyclohexane, reflux in nitrogen and oil bath at 70-90℃ for 5-8 hours, and add anhydrous ethanol to obtain styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine.

[0015] The present invention discloses a method for preparing styrene-butadiene rubber (graft-4,4'-dithiodiphenylamine) including steps such as dissolving in a solvent, reacting with formic acid and hydrogen peroxide, washing and drying, and reacting with 4,4'-dithiodiphenylamine. Through the synergistic effect of these steps, styrene-butadiene rubber (graft-4,4'-dithiodiphenylamine) can be accurately synthesized, ensuring that its chemical structure and properties meet requirements, thereby guaranteeing the self-healing function of the coating. Strict washing and drying steps remove impurities, yielding a high-purity modified rubber, further improving the quality and performance of the coating.

[0016] Further, in step S1, the weight ratio of the styrene-butadiene rubber, formic acid, and hydrogen peroxide is 10:(1-1.5):(0.4-0.5); the amount of solvent (e.g., n-hexane) is 4-10 times the mass of the styrene-butadiene rubber; and the amount of anhydrous alcohol is 6-15 times the mass of the styrene-butadiene rubber.

[0017] By precisely controlling the proportion of each raw material in step S1, reaction conditions can be optimized, and reaction efficiency and product quality can be improved.

[0018] Further, in step S3, the weight ratio of epoxy styrene-butadiene rubber to 4,4'-dithiodiphenylamine is 1:(0.1-0.3); the amount of cyclohexane used is 4-10 times the mass of epoxy styrene-butadiene rubber; and the amount of anhydrous alcohol used is 6-15 times the mass of epoxy styrene-butadiene rubber.

[0019] By precisely controlling the proportions of each raw material in step S3, reaction conditions can be optimized, and reaction efficiency and product quality can be improved.

[0020] Furthermore, the aromatic oil contains no less than 70% aromatics. Aromatic oils with a higher aromatic content are more compatible with other raw materials such as asphalt, enhancing the flexibility and waterproofing properties of the coating. Simultaneously, a high aromatic content helps improve the coating's weather resistance and chemical resistance, extending the service life of the waterproof layer.

[0021] Furthermore, the asphalt is one or both of 70# and 90# asphalt. By selecting these two types of asphalt, a better synergistic effect can be achieved with other components, improving the overall performance of the waterproof coating.

[0022] Furthermore, the solid content of the styrene-butadiene rubber latex is 50-70%. This range of solid content ensures that the styrene-butadiene rubber latex plays a good toughening and modifying role in the coating, while also guaranteeing the coating's workability and drying speed. Excessive solid content may lead to excessively high coating viscosity, making application difficult; insufficient solid content may affect the coating's waterproof performance and self-healing function.

[0023] Preferably, the solid content of the styrene-butadiene rubber latex is 60-70%, more preferably 62-68%.

[0024] Furthermore, it also includes 0.4-2 parts of other adjuvants.

[0025] Preferably, the other additives include 0.2-2 parts of pH adjuster, 0.1-0.5 parts of thickener, and 0.1-0.5 parts of defoamer.

[0026] Preferably, the pH adjuster is one or more of glacial acetic acid, sodium hydrogen phosphate, dilute hydrochloric acid, and dilute sulfuric acid. By selecting a suitable type of pH adjuster and maintaining it within a suitable range (e.g., 2-4), the stability and emulsification effect of the coating can be optimized, preventing adverse reactions or stratification of raw materials during emulsification, and ensuring the quality and performance of the coating.

[0027] Thickeners can adjust the viscosity of coatings, giving them good workability and facilitating application methods such as brushing and spraying. The thickener is one of BASF CO 40, Dow ASE60, and sodium carboxymethyl cellulose (CMC); these types of thickeners can form better synergistic effects with other components of the waterproof coating of this invention, improving the overall performance of the waterproof coating.

[0028] Defoamers effectively suppress and eliminate air bubbles, ensuring the uniformity and density of the coating and improving the quality and durability of the waterproof layer. The defoamer is one or more of Dow AFE1410, Zhonglianbang B313, Zhonglianbang 314, and Zhonglianbang 315. These types of defoamers can form a better synergistic effect with other components of the waterproof coating of this invention, improving the overall performance of the waterproof coating.

[0029] Furthermore, the powder is one or both of barium sulfate and talc. As inorganic solid powders, barium sulfate and talc can fill the tiny voids in the coating, improving its density and waterproofing performance. Simultaneously, these powders can also enhance the mechanical properties of the coating, such as hardness and abrasion resistance, making it more durable during use and extending the service life of the waterproof layer.

[0030] Furthermore, the emulsifier is a cationic emulsifier; cationic emulsifiers can form a stable emulsion system with raw materials such as asphalt, ensuring that the coating does not undergo stratification, precipitation, or other phenomena during preparation and storage, thus guaranteeing the quality and performance stability of the coating.

[0031] Preferably, the emulsifier is selected from one or more of amide emulsifier X42, dodecyl ammonium chloride, and imidazoline amide. Selecting a specific cationic emulsifier can improve the compatibility between raw materials in the coating, especially its synergistic effect with styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine, further enhancing the coating's self-healing function and overall performance.

[0032] According to a second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned self-healing emulsified bitumen waterproof coating, comprising the following steps:

[0033] Aromatic oil and asphalt are stirred and heated to a first temperature, then styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine is added, and the mixture is heated to a second temperature to obtain a mixture; the obtained mixture is then self-ground to obtain a modified rubber compound;

[0034] Add the pH adjuster and emulsifier from other additives to a portion of water and mix to obtain an emulsion;

[0035] The modified rubber compound and the emulsion are circulated and emulsified to obtain an emulsified modified material;

[0036] The styrene-butadiene rubber emulsion, powder, thickener and defoamer from other additives, and the remaining water are mixed together and then mixed with the emulsion modified material.

[0037] The preparation method of this invention has a simple and clear process flow, is easy to operate, control, and implement, and is suitable for large-scale industrial production. Through gradual heating, mixing, grinding, and emulsification, the reaction and dispersion effects between the raw materials can be fully guaranteed, allowing the coating performance to reach its optimal state and producing a high-performance self-healing emulsified asphalt waterproof coating. In particular, the cyclic emulsification step further improves the emulsification effect, ensuring the stability and uniformity of the coating, thereby improving the consistency and reliability of the product quality.

[0038] Further, the first temperature is 120-140℃; the second temperature is 170-190℃; and the mixing time after adding the styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine is 100-150 min.

[0039] This invention ensures sufficient reaction and uniform mixing of raw materials by precisely controlling the first temperature (120-140℃) and the second temperature (170-190℃), as well as the mixing time (100-150 min) after adding styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine at the second temperature. This optimized process not only promotes the effective grafting and dispersion of styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine with components such as asphalt, enhancing the self-healing function and low-temperature flexibility of the coating, but also improves the overall performance stability of the coating.

[0040] Furthermore, the self-grinding time is 0.5-1.5 hours. By controlling the self-grinding time within the above range, the present invention can effectively refine and uniformly disperse the components in the modified rubber compound, especially the mixture of styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine and asphalt. This process step not only improves the microscopic uniformity of the coating and enhances the interaction between the components, but also further improves the flexibility, adhesion strength, and self-healing properties of the coating.

[0041] Furthermore, the temperature of the cyclic emulsification is 40-50℃, and the time is 20-40 minutes. This invention achieves efficient emulsification of the modified adhesive and the emulsion by controlling the temperature and time of the cyclic emulsification within the above range. This not only ensures the stability of the emulsification process, allowing the modified adhesive to be uniformly dispersed in the emulsion to form a fine and stable emulsion system, but also further enhances the waterproof performance and application properties of the coating.

[0042] Furthermore, the water used in the emulsion accounts for 60-80% of the total water mass. By controlling the percentage of water used in the emulsion within the above-mentioned range, this invention can effectively adjust the concentration and viscosity of the emulsion, thereby optimizing the efficiency and stability of the emulsification process. This precise control of the ratio not only ensures good compatibility between the emulsion and the modified adhesive, making the emulsion system more uniform and delicate, but also improves the overall stability of the coating and prevents stratification or sedimentation. Simultaneously, a reasonable water ratio helps regulate the drying speed and film-forming properties of the coating, enabling it to form a uniform and dense waterproof layer on different construction environments and substrates, further enhancing the application performance and waterproofing effect of the waterproof coating.

[0043] The beneficial effects of this invention are:

[0044] This invention provides a self-healing emulsified asphalt waterproof coating. By introducing styrene-butadiene rubber (graft-4,4'-dithiodiphenylamine) as a key modifying component and optimizing the formulation and process, it achieves excellent self-healing function, significantly improved low-temperature flexibility, and enhanced adhesion. Simultaneously, it optimizes application performance and overall performance, maintaining good waterproofing effects in various complex environments. Furthermore, this coating uses water as a solvent, making it environmentally friendly and pollution-free. Its preparation method is simple and efficient, with low production costs, resulting in significant economic benefits and broad application prospects. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0046] The raw materials used in the following examples and comparative examples are sourced from the following sources:

[0047] Aromatic Oil I: Waterproof Aromatic Oil from Shandong Furunda Chemical Co., Ltd.;

[0048] Styrene-butadiene rubber: Shandong Qilu Petrochemical SBR1502;

[0049] Base asphalt: Foshan Gaofu PetroChina Fuel Asphalt Co., Ltd. 70# asphalt;

[0050] Emulsifier: cetyltrimethylammonium chloride, supplier: Shandong Deyitai New Materials Co., Ltd.;

[0051] pH adjuster: Sodium hydrogen phosphate, Shaanxi Chenming Biotechnology Co., Ltd.;

[0052] Thickener: Dow ASE60;

[0053] Defoamer: Dow AFE1410;

[0054] Inorganic solid powder: Talc powder BHS-818S from Quanzhou Xufeng Powder Raw Materials Co., Ltd.;

[0055] Styrene-butadiene rubber latex: 65% styrene-butadiene rubber latex from Shandong Haifang Technology Co., Ltd.

[0056] Example 1

[0057] This embodiment provides a self-healing emulsified asphalt waterproof coating, which is composed of the following components in parts by weight as shown in Table 1.

[0058] The styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine used in this embodiment is a laboratory-synthesized modified rubber obtained by reacting styrene-butadiene rubber with 4,4'-dithiodiphenylamine after epoxidation modification; the specific preparation method is as follows:

[0059] 100g of styrene-butadiene rubber (SBR) was dissolved in 500g of n-hexane, and 11g of formic acid was added. The mixture was kept in a water bath at 30-40℃, and 4.5g of hydrogen peroxide was slowly added dropwise. After stirring for 9 hours, 200g of anhydrous ethanol was added to precipitate the epoxidized SBR product. The solid powder was repeatedly washed with 800g of anhydrous ethanol to remove formic acid and hydrogen peroxide, and dried to obtain pure epoxy SBR. 100g of epoxy SBR and 21g of 4,4'-dithiodiphenylamine were dissolved in 500g of cyclohexane. The mixture was refluxed for 6.5 hours under nitrogen atmosphere and an oil bath at 80℃. 300g of anhydrous ethanol was added to obtain SBR-graft-4,4'-dithiodiphenylamine, completing the grafting modification of SBR. The weight ratio of the grafted product to the main chain in SBR-graft-4,4'-dithiodiphenylamine was 0.865:10.

[0060] This embodiment also provides a method for preparing the self-healing emulsified asphalt waterproof coating, including the following steps:

[0061] Step (1): Add aromatic oil and base asphalt to the reactor, stir and heat to 130°C, then slowly add styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine powder, heat to 180°C and stir for 120 min.

[0062] Step (2): Grind the rubber material obtained in step (1) by self-grinding it in a colloid mill for 1 hour to obtain the modified rubber material.

[0063] Step (3): Add pH adjuster and emulsifier to 70% of the required deionized water for the formula, mix thoroughly, heat to 30-40℃, adjust the pH value to 2-4, and obtain the emulsion.

[0064] Step (4): The modified rubber material prepared in step (2) and the emulsion prepared in step (3) are circulated and emulsified in a colloid mill for 30 minutes, and the emulsification temperature is controlled at 40-50℃ to obtain the emulsified modified material.

[0065] Step (5): Add 65% styrene-butadiene emulsion, inorganic solid powder, thickener, and defoamer to the remaining deionized water and stir thoroughly to disperse them, thus obtaining a mixture.

[0066] Step (6): Thoroughly mix the mixture obtained in step (5) with the emulsion modified material obtained in step (4).

[0067] Examples 2-9

[0068] Examples 2-9 each independently provide a self-healing emulsified bitumen waterproof coating, which is composed of the components listed in Table 1 by weight. The preparation method of the self-healing emulsified bitumen waterproof coating in these examples is the same as in Example 1.

[0069] Table 1

[0070]

[0071] Comparative Example 1

[0072] This comparative example provides a self-healing emulsified bitumen waterproof coating, the difference in raw material composition from Example 2 being that an equal mass of styrene-butadiene-styrene copolymer is used instead of styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine. All other aspects are the same as in Example 2.

[0073] The preparation method of this self-healing emulsified asphalt waterproof coating is the same as in Example 2.

[0074] Comparative Example 2

[0075] This comparative example provides a self-healing emulsified bitumen waterproof coating, the difference in raw material composition from Example 2 being that an equal mass of styrene-butadiene rubber is used instead of styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine. All other aspects are the same as in Example 2.

[0076] The preparation method of this self-healing emulsified asphalt waterproof coating is the same as in Example 2.

[0077] Comparative Example 3

[0078] This comparative example provides a self-healing emulsified bitumen waterproof coating, the difference in raw material composition from Example 2 being that an equal mass of acrylic emulsion is used instead of styrene-butadiene rubber emulsion. All other aspects are the same as in Example 2.

[0079] The preparation method of this self-healing emulsified asphalt waterproof coating is the same as in Example 2.

[0080] Comparative Example 4

[0081] This comparative example provides a self-healing emulsified bitumen waterproof coating, the difference in raw material composition from Example 2 being that styrene-butadiene rubber and 4,4'-dithiodiphenylamine are used in equal grafting ratios instead of styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine. All other aspects are the same as in Example 2.

[0082] The preparation method of this self-healing emulsified asphalt waterproof coating is the same as in Example 2.

[0083] Comparative Example 5

[0084] This comparative example provides a self-healing emulsified bitumen waterproof coating, the difference in raw material composition from Example 2 being that the amount of base bitumen is 40 parts. All other aspects are the same as in Example 2.

[0085] The preparation method of this self-healing emulsified asphalt waterproof coating is the same as in Example 2.

[0086] Test case

[0087] The self-healing emulsified bitumen waterproof coatings obtained in the examples and comparative examples were tested using the same process. The results are shown in Table 2.

[0088] Test standard for low-temperature flexibility and bonding strength: JC / T408-2005.

[0089] Self-healing test standard: Refer to JC / T2678-2022.

[0090] Table 2

[0091]

[0092] As can be seen from the experimental data in Table 2, the test results of Examples 1-9 show that the self-healing emulsified asphalt waterproof coating of the present invention performs well in terms of low-temperature flexibility (no cracking at -15℃), bonding strength (0.34-0.81 MPa) and self-healing properties (no water seepage).

[0093] In Comparative Examples 1, 2, and 3, the self-healing properties were significantly poor due to the lack of key modifying components (such as styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine) or the use of other substitute components, and some areas showed water seepage. This further demonstrates the importance of key modifying components in achieving the self-healing function.

[0094] Compared to Example 2, Comparative Example 4 only physically mixed styrene-butadiene rubber with 4,4'-dithiodiphenylamine without forming a grafted structure. As a result, cracks appeared at -15°C, and the bond strength dropped to 0.21 MPa. The comparison shows that the grafted styrene-butadiene rubber-graft-4,4'-dithiodiphenylamine can simultaneously impart excellent low-temperature flexibility, high bond strength, and self-healing properties to the coating.

[0095] Example 2 showed no cracking at -15℃, a bonding strength of 0.81 MPa, and no water seepage, demonstrating excellent low-temperature flexibility, adhesion, and self-healing properties. In contrast, Comparative Example 5, due to the increase of asphalt content to 40 parts, resulted in cracking at -15℃, a bonding strength of only 0.18 MPa, and water seepage, indicating that excessive asphalt can deteriorate the low-temperature toughness, bonding performance, and self-healing ability of the coating.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-healing emulsified asphalt waterproofing coating, characterized by, The raw materials include the following components by weight: aromatic hydrocarbon oil 5-10 parts, butadiene styrene rubber-graft-4,4'-dithiodiamine 4-8 parts, asphalt 20-35 parts, emulsifier 4-8 parts, water 30-50 parts, powder 10-20 parts, and butadiene styrene rubber emulsion 1-3 parts.

2. The self-healing emulsified asphalt waterproof coating material according to claim 1, characterized in that, In the butadiene styrene rubber-graft-4,4'-dithiodiamine, the weight ratio of the graft to the main chain is (0.5-1):

10.

3. The self-healing emulsified asphalt waterproof coating material according to claim 1, characterized in that, The preparation method of the butadiene styrene rubber-graft-4,4'-dithiodiamine is as follows: Step S1: Dissolve butadiene styrene rubber in a solvent, add formic acid, control the temperature at 30-40℃, add hydrogen peroxide, stir for 8-10 hours, and then add anhydrous alcohol to obtain butadiene styrene rubber epoxidation product precipitate; Step S2: Wash and dry the butadiene styrene rubber epoxidation product precipitate to obtain epoxy butadiene styrene rubber; Step S3: Dissolve the epoxy butadiene styrene rubber and 4,4'-dithiodiamine in cyclohexane, reflux at 70-90℃ under nitrogen atmosphere for 5-8 hours, and then add anhydrous alcohol to obtain butadiene styrene rubber-graft-4,4'-dithiodiamine.

4. The self-healing emulsified asphalt waterproof coating material according to claim 3, characterized in that, In step S1, the weight ratio of butadiene styrene rubber, formic acid, and hydrogen peroxide is 10:(1-1.5):(0.4-0.5); the amount of the solvent is 4-10 times the mass of the butadiene styrene rubber; and the amount of anhydrous alcohol is 6-15 times the mass of the butadiene styrene rubber. In step S3, the weight ratio of epoxy butadiene styrene rubber to 4,4'-dithiodiamine is 1:(0.1-0.3); the amount of cyclohexane is 4-10 times the mass of the epoxy butadiene styrene rubber; and the amount of anhydrous alcohol is 6-15 times the mass of the epoxy butadiene styrene rubber.

5. The self-healing emulsified asphalt waterproof coating according to any one of claims 1-4, characterized in that, The aromatic hydrocarbon oil contains not less than 70% aromatic hydrocarbons; and / or the asphalt is one or both of 70# asphalt and 90# asphalt; and / or the solid content of the butadiene styrene rubber emulsion is 50-70%.

6. The self-healing emulsified asphalt waterproof coating material according to claim 1, characterized in that, It also includes other auxiliary agents 0.4-2 parts.

7. The self-healing emulsified asphalt waterproof coating material according to claim 6, characterized in that, The other auxiliary agents include pH adjuster 0.2-2 parts, thickening agent 0.1-0.5 parts, and defoaming agent 0.1-0.5 parts.

8. The self-healing emulsified asphalt waterproof coating material according to claim 7, characterized in that, The pH adjuster is one or more of glacial acetic acid, sodium hydrogen phosphate, dilute hydrochloric acid, and dilute sulfuric acid; the thickening agent is one of BASF CO 40, Dow ASE60, and sodium carboxymethyl cellulose CMC; and the defoaming agent is one or more of Dow AFE1410, Zhonglian B313, Zhonglian 314, and Zhonglian 315.

9. The self-healing emulsified asphalt waterproof coating material according to claim 1, characterized in that, The powder is one or both of barium sulfate and talcum powder.

10. The self-healing emulsified asphalt waterproof coating material according to claim 1, characterized in that, The emulsifier is a cationic emulsifier.

11. The self-healing emulsified asphalt waterproof coating material according to claim 10, characterized in that, The emulsifier is selected from one or more of amide emulsifier X42, dodecyl ammonium chloride, and imidazoline amide.

12. The method for preparing a self-healing emulsified asphalt waterproof coating according to claim 7 or 8, characterized in that, The method includes the following steps: Stir the aromatic hydrocarbon oil and asphalt to warm up to a first temperature, then add butadiene styrene rubber-graft-4,4'-dithiodiamine, warm up to a second temperature, mix, obtain a mixed solution, and then self-grind the mixed solution to obtain modified rubber; Mix the pH adjuster and emulsifier in the other auxiliary agents in part of the water to obtain an emulsion; The modified rubber and the emulsion are subjected to circulation emulsification to obtain emulsified modified rubber; The butadiene styrene rubber emulsion, the powder, the thickening agent and the defoaming agent in the other additives, and the remaining water are mixed and then mixed with the emulsified modified rubber.

13. The preparation method of the self-healing emulsified asphalt waterproof coating according to claim 12, characterized in that, The first temperature is 120-140℃; the second temperature is 170-190℃, and the mixing time after the butadiene styrene rubber-graft-4,4'-dithiodianiline is added is 100-150min; And / or, the self-grinding time is 0.5-1.5h; And / or, the temperature of the circulation emulsification is 40-50℃, and the time is 20-40min; And / or, the part of the water used in the emulsion accounts for 60-80% of the total mass of the water.

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