Photocatalytic self-repairing polymer asphalt waterproof coating and preparation method thereof

Abstract

The invention provides a photocatalytic self-repairing polymer asphalt waterproof coating and a preparation method of the photocatalytic self-repairing polymer asphalt waterproof coating. The waterproof coating is prepared from the following raw materials: 40 to 50 parts of petroleum asphalt, 25 to 35 parts of styrene-acrylate copolymer emulsion, 4 to 6 parts of photothermal conversion agent, 8 to 12 parts of dynamic borate bond hyperbranched self-repairing agent, 6 to 10 parts of cation modified halloysite nanotube, 3 to 8 parts of maleic anhydride grafted POE (Polyolefin Elastomer), 1 to 2 parts of emulsifier, 0.5 to 1.5 parts of dispersant and 1 to 3 parts of rheology modifier. The water-based paint comprises the following components in parts by weight: 30-60 parts of water, 0.3-0.8 part of a light stabilizer, 0.5-1.0 part of an amine buffering agent, 0.8-1.5 parts of a dehydrating agent and 18-28 parts Through the combined action of all the components, the waterproof coating has the properties of waterproofness, self-repairing, stable use and the like.

Description

Technical Field

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

[0002] Polymer-modified asphalt waterproof coatings are functional building materials made from petroleum asphalt as a base material, modified with composite polymers and various additives. They are widely used in waterproofing projects in construction and infrastructure. Existing technologies utilize polymer modification to improve the flexibility and weather resistance of asphalt. Some products also incorporate self-healing mechanisms to repair micro-cracks that develop during use, extending the service life of the waterproof layer.

[0003] However, the development of self-healing asphalt waterproof coatings in the existing technology still faces bottlenecks: on the one hand, the self-healing function mostly relies on external heating or artificial intervention, lacking an efficient visible light autonomous response triggering mechanism, and the repair efficiency is difficult to meet the actual engineering needs; on the other hand, the dispersion stability of each component in the system is insufficient, and agglomeration is prone to occur, affecting the interfacial adhesion performance and anti-seepage effect after the coating film is formed, making it difficult to balance long-term waterproof reliability and self-healing efficiency. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a photocatalytic self-healing polymer bitumen waterproof coating and its preparation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention discloses a photocatalytic self-healing polymer asphalt waterproof coating, the raw materials for which are prepared by weight are: 40-50 parts petroleum asphalt, 25-35 parts styrene-acrylate copolymer emulsion, 4-6 parts photothermal conversion agent, 8-12 parts dynamic borate ester bond hyperbranched self-healing agent, 6-10 parts cationic modified halloysite nanotubes, 3-8 parts maleic anhydride grafted POE elastomer, 1-2 parts emulsifier, 0.5-1.5 parts dispersant, 1-3 parts rheology modifier, 0.3-0.8 parts light stabilizer, 0.5-1.0 parts amine buffer, 0.8-1.5 parts dehydrating agent, and 18-28 parts deionized water.

[0007] Using the above technical solutions, petroleum asphalt can serve as a continuous phase base material, providing an initial waterproof barrier and substrate wetting performance; styrene-acrylate copolymer emulsion can form an interpenetrating network with petroleum asphalt, enhancing the elastic recovery capability of the coating; photothermal conversion agent can achieve a visible light-responsive photothermal effect, providing energy for the repair process; epoxidized soybean oil undergoes a ring-opening reaction with the terminal hydroxyl groups released after deacetylation of the hyperbranched self-healing agent via epoxy groups, introducing a flexible long-chain structure, reducing the interfacial tension between the self-healing agent and asphalt and polymer emulsion, and improving compatibility with the coating system; cationic modified halloysite nanotubes can anchor other components in the system through electrostatic adsorption, improving the dispersion stability of each component in the system and delaying water penetration; maleic anhydride grafted onto POE elastomer maleic anhydride groups... It can undergo esterification and amidation reactions with active groups such as carboxyl and hydroxyl groups in petroleum asphalt, improving the interfacial adhesion between asphalt and polymers; emulsifiers can promote the emulsification and dispersion of petroleum asphalt; dispersants can ensure the stable dispersion of each solid component in the system and reduce agglomeration; rheology modifiers can adjust the rheological properties of coatings and ensure morphological stability during construction; light stabilizers can improve the UV aging resistance of coatings; amine buffers can neutralize acidic products such as boric acid generated by the hydrolysis of borate ester bonds in the system, maintain the pH stability of the system, avoid the acidic environment from damaging the stability of dynamic borate ester bonds, and thus ensure the long-term effectiveness of self-healing function; dehydrating agents can control the moisture content of the system and improve the storage stability of coatings; deionized water can provide a medium for the dispersion of each component and adjust the solid content of the system to a suitable range.

[0008] Preferably, the emulsifier is one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium diisooctyl succinate sulfonate; the dispersant is one of sodium polycarboxylate or sodium polyacrylate; and the rheology modifier is one or more of organobentonite, hydrophobic fumed silica, and polyamide wax.

[0009] Using the above technical solution, one or more of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and sodium diisooctyl succinate sulfonate can be used as emulsifiers to reduce the interfacial tension between water and petroleum asphalt, promote the emulsification and dispersion of petroleum asphalt in the aqueous phase, and form a stable asphalt emulsion; one of sodium polycarboxylate or sodium polyacrylate can be used as a dispersant to stably disperse the solid components in the coating system through electrostatic repulsion and steric hindrance, reducing the agglomeration of solid components; one or more of organobentonite, hydrophobic fumed silica, and polyamide wax can be used as rheology modifiers to adjust the rheological properties of the coating, improve the thixotropy and construction stability of the coating, make the coating less prone to sagging during construction, and ensure uniform coating thickness.

[0010] Preferably, the light stabilizer is one of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and bis(2,2,6,6-tetramethyl-4-piperidinyl) maleate; the amine buffer is one or more of N-methyldiethanolamine, triethanolamine, and diethanolamine; and the dehydrating agent is a molecular sieve.

[0011] Using the above technical solution, one of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and bis(2,2,6,6-tetramethyl-4-piperidinyl) maleate is a light stabilizer, which can slow down the degradation effect of ultraviolet light on coating components, improve the anti-ultraviolet aging performance of the coating, and extend the service life of the coating; one or more of N-methyldiethanolamine, triethanolamine, and diethanolamine are used as amine buffers to neutralize acidic products generated in the coating system and maintain the pH stability of the system; molecular sieves are used as dehydrating agents to adsorb residual moisture in the coating system, control the water content of the system, and ensure the storage stability of the coating.

[0012] Preferably, the raw materials for preparing the photothermal conversion agent, by weight, include: 10-15 parts melamine, 1-2 parts ammonium dihydrogen phosphate, 2-3 parts citric acid, 1-1.5 parts ethylenediamine, 0.5-1.0 parts zinc acetate, 0.3-0.5 parts silane coupling agent KH-792, 100-150 parts deionized water, and 50-80 parts anhydrous ethanol.

[0013] Using the above technical solution, melamine and ammonium dihydrogen phosphate, as raw materials for preparing phosphorus-doped carbon nitride matrix, can provide carbon and nitrogen sources and phosphorus doping elements, laying the foundation for the formation of the core structure of photothermal conversion; citric acid and ethylenediamine, as precursors of carbon quantum dots, can synthesize carbon quantum dots with specific properties, which, together with phosphorus-doped carbon nitride and zinc oxide nanocrystals, can construct a visible light-responsive ternary heterojunction. This heterojunction can synergistically broaden the visible light absorption range and improve the photothermal conversion efficiency; zinc acetate can provide zinc ions, which, through hydrolysis, generate zinc oxide nanocrystals, which, together with phosphorus-doped carbon nitride and carbon quantum dots, constitute a visible light-responsive ternary heterojunction; silane coupling agent KH-792 can modify the surface of the ternary heterojunction with amination, improving its dispersion stability in the coating system; deionized water and anhydrous ethanol, as reaction media, can provide a suitable environment for each step of the preparation reaction, ensuring the smooth synthesis of the photothermal conversion agent.

[0014] Preferably, the preparation method of the photothermal conversion agent includes the following steps:

[0015] 1) Place melamine and ammonium dihydrogen phosphate in a ball mill and grind them at a speed of 300-400 r / min for 20-30 min to ensure they are thoroughly mixed. Then transfer the mixture to a crucible and heat it to 520-550℃ at a speed of 2-4℃ / min. Hold the temperature for 3.5-4.5 h and cool it to 20-25℃ to obtain phosphorus-doped carbon nitride.

[0016] 2) Dissolve citric acid and ethylenediamine in 1 / 2-1 / 3 of the total volume of deionized water, stir at 200-300 r / min for 10-15 min to mix the system evenly, then adjust the pH to 6.5-7.0 with 0.08-0.12 mol / L sodium hydroxide solution, transfer to a high-pressure reactor, react at 175-185℃ for 5.5-6.5 h, cool to 20-25℃, and filter through a 0.20-0.22 μm filter membrane to obtain a carbon quantum dot solution;

[0017] 3) Disperse the phosphorus-doped carbon nitride obtained in step 1) in the remaining deionized water, add zinc acetate, and disperse for 30-40 min under ultrasonic power of 260-300 W and frequency of 32-40 kHz. Then add the carbon quantum dot solution obtained in step 2), stir at 200-300 r / min for 10-15 min to mix the system evenly, and then adjust the pH to 5.5-6.0 with 0.8-1.2 mol / L hydrochloric acid solution. Stir the reaction at 150-250 r / min for 1.5-2.5 h under water bath conditions of 75-85℃.

[0018] 4) Disperse the product obtained in step 3) in anhydrous ethanol, add silane coupling agent KH-792, and stir the reaction at 300-400 r / min for 3.5-4.5 h under reflux at 55-65 °C. Then centrifuge at 7600-8000 r / min for 10-15 min, wash the precipitate with anhydrous ethanol 3-4 times, and dry it under vacuum of -0.085~-0.095 MPa and temperature of 60-80 °C for 10-12 h to obtain the photothermal conversion agent.

[0019] Using the above technical solutions, grinding and high-temperature treatment can fully mix melamine and ammonium dihydrogen phosphate and react to generate phosphorus-doped carbon nitride; hydrothermal reaction can synthesize stable carbon quantum dots; ultrasonic dispersion can improve the dispersion uniformity of phosphorus-doped carbon nitride and zinc acetate, and subsequent water bath reaction can promote the hydrolysis of zinc acetate to generate zinc oxide nanocrystals, while realizing the composite formation of carbon quantum dots, zinc oxide and phosphorus-doped carbon nitride into a ternary heterojunction; modification with silane coupling agent KH-792 and centrifugal washing and drying can perform surface amination treatment on the ternary heterojunction and purify the product, finally obtaining a photothermal conversion agent with good dispersion stability and visible light response photothermal conversion performance.

[0020] Preferably, the raw materials for preparing the dynamic borate ester bond hyperbranching self-healing agent, by weight, include: 4-6 parts of trimethylolpropane, 8-12 parts of 2,2-dimethylolbutyric acid, 0.15-0.25 parts of p-toluenesulfonic acid, 15-20 parts of epoxidized soybean oil, 1.5-2.5 parts of boric acid, 1.0-1.5 parts of acetyl chloride, 1.2-1.8 parts of triethylamine, 30-40 parts of anhydrous xylene, and 5-10 parts of deionized water.

[0021] Using the above technical solution, trimethylolpropane and 2,2-dimethylolbutyric acid can be used as monomers to construct a hyperbranched polyester skeleton; p-toluenesulfonic acid can be used as a catalyst to promote the efficient esterification reaction; epoxidized soybean oil can participate in the modification to improve the compatibility of the product with the coating system; boric acid is used to introduce dynamic borate ester bonds, providing a core site for the self-healing function; acetyl chloride can block the terminal hydroxyl groups, reducing the risk of hydrolysis during storage; triethylamine can be used as an acid-binding agent to regulate the reaction system; anhydrous xylene provides a homogeneous reaction medium to ensure the smooth progress of the reaction; deionized water can assist in the subsequent washing process and help purify the product; under visible light irradiation, the heat generated by the photothermal conversion agent can trigger the deprotection reaction of the acetyl groups, releasing the terminal hydroxyl groups, restoring the reversibility of the dynamic borate ester bonds, and thus realizing the self-healing function.

[0022] Preferably, the preparation method of the dynamic borate ester bond hyperbranched self-healing agent includes the following steps:

[0023] (1) Under nitrogen protection, trimethylolpropane, 2,2-dimethylolbutyric acid, p-toluenesulfonic acid and anhydrous xylene are added to the reaction vessel in sequence. The mixture is stirred at 200-300 r / min for 15-25 min at 20-40℃. Then, under nitrogen protection, the temperature is raised to 140-150℃ and stirred at 150-250 r / min for 6-8 h. When the acid value drops to 20-30 mg KOH / g, the heating is stopped. The mixture is then distilled under reduced pressure at a vacuum of -0.085~-0.095 MPa and a temperature of 75-85℃ for 40-60 min until no obvious distillate flows out. The anhydrous xylene is recovered to obtain the hydroxyl-terminated hyperbranched polyester.

[0024] (2) Dissolve the end-hydroxyl hyperbranched polyester obtained in step (1) in anhydrous xylene in 2-3 times its mass, add boric acid, and stir at 150-250 r / min at 110-120℃ for 4-5 h. After the reaction is completed, cool down to 10-15℃, and add acetyl chloride and triethylamine dropwise at a rate of 0.5-1.5 mL / min while stirring continuously at 150-250 r / min. After all the addition is completed, continue stirring at 10-15℃ for 1.5-2.5 h.

[0025] (3) Heat the product obtained in step (2) to 80-90℃, add epoxidized soybean oil and deionized water, react at 150-250r / min for 2-3h, and then distill under reduced pressure at a vacuum of -0.09~-0.10MPa and a temperature of 80-90℃ for 2.5-3.5h to remove solvent and low-boiling substances. Stop distillation when there is no obvious distillate to obtain the dynamic borate bond hyperbranching self-repairing agent.

[0026] Using the above technical solution, nitrogen protection can prevent material oxidation during the reaction process and ensure stable reaction. Heating and stirring the reaction can promote the formation of a hydroxyl-terminated hyperbranched polyester skeleton between trimethylolpropane and 2,2-dimethylolbutyric acid. Vacuum distillation can effectively remove solvents and achieve preliminary product purification. The reaction between boric acid and hydroxyl-terminated groups can introduce dynamic borate ester bonds. The addition of acetyl chloride and triethylamine at low temperature can achieve acetylation and closure of the terminal groups to reduce the risk of hydrolysis during storage. The addition of epoxidized soybean oil can modify the product and improve its compatibility with the coating system. Subsequent vacuum distillation can further remove solvents and low-boiling substances to complete purification, and finally obtain a dynamic borate ester bond hyperbranched self-healing agent with dynamic self-healing activity and storage stability.

[0027] This invention also discloses a method for preparing a photocatalytic self-healing polymer bitumen waterproof coating, comprising the following steps:

[0028] S1. Heat petroleum asphalt to 130-140℃ to melt it, add maleic anhydride-grafted POE elastomer, shear and disperse it at a speed of 1000-1200r / min for 30-40min, cool it down to 110-120℃ and hold it for 10-15min to obtain modified asphalt melt.

[0029] S2. Take 60%-70% of the total amount of deionized water and heat it to 40-50℃. Add emulsifier, dispersant and light stabilizer, and stir to dissolve for 10-15 minutes at 800-1000 r / min. Add the cationic modified halloysite nanotubes to the system in three batches and disperse them at 2000-2500 r / min for 36-45 minutes to obtain a suspension.

[0030] S3. Add styrene-acrylate copolymer emulsion to step S2 and stir at 1200-1500 r / min for 20-25 min. Then slowly add the modified asphalt melt obtained in step S1, while stirring at 2500-3000 r / min. The addition time is controlled at 15-20 min. After the addition is complete, continue stirring for 25-30 min to obtain asphalt-based composite emulsion.

[0031] S4. Add the photothermal conversion agent to the remaining deionized water and ultrasonically disperse it for 15-20 minutes under ultrasonic power of 230-250W and frequency of 36-40kHz. Add the asphalt-based composite emulsion obtained in step S3 and disperse it for 30-35 minutes at 1500-1800r / min. Then, slowly add the dynamic borate ester bond hyperbranched self-healing agent at 35-40℃ and stir at 800-1000r / min for 40-50 minutes. Add the dehydrating agent and continue stirring for 10-15 minutes.

[0032] S5. Stir the system obtained in step S4 at 600-800 r / min, add the rheology modifier, and continue stirring for 20-25 min. Then add the amine buffer and continue stirring for 15-20 min. Then, vacuum degassing is performed for 10-15 min under vacuum conditions of -0.085~-0.095 MPa and 35-40℃. The undispersed solid particles and impurities are removed by normal pressure filtration through a 180-200 mesh sieve to ensure product uniformity, thus obtaining a photocatalytic self-healing polymer asphalt waterproof coating.

[0033] Using the above technical solutions, maleic anhydride-grafted POE elastomer-modified petroleum asphalt can improve the flexibility and interfacial bonding of asphalt; the high-speed dispersion of cationic modified halloysite nanotubes can form a stable suspension, providing a basis for subsequent component anchoring; the emulsification and composite of styrene-acrylate copolymer emulsion and modified asphalt can improve the system compatibility and form a stable asphalt-based composite emulsion; the ultrasonic dispersion of photothermal conversion agent can avoid agglomeration and ensure its photothermal conversion efficiency; the addition of dynamic borate bond hyperbranched self-healing agent at a suitable temperature can retain its self-healing activity and be uniformly integrated into the system; the dehydrating agent can reduce the moisture content of the system and improve storage stability; the rheology modifier can adjust the viscosity of the system and optimize the construction performance; the amine buffer can maintain the pH stability of the system and protect the dynamic borate bond; vacuum degassing and filtration can remove impurities and bubbles, ultimately obtaining a polymer asphalt waterproof coating with uniformly dispersed components, stable storage, good construction properties, and photocatalytic self-healing function.

[0034] Preferably, in step S2, the cationic modified halloysite nanotubes added three times have the same mass, and each addition needs to be spaced 4-5 minutes apart.

[0035] By adopting the above technical solution, it is possible to avoid the agglomeration caused by excessive local concentration due to excessive single addition; the interval time can provide sufficient dispersion time for the previous batch of nanotubes, so that they can be fully dispersed in the aqueous phase system under the action of the dispersant; ultimately, it can ensure that the cationic modified halloysite nanotubes are uniformly distributed in the suspension, improve the stability of the suspension, and lay the foundation for subsequent electrostatic anchoring with other components.

[0036] Preferably, in step S4, the ultrasound working mode is: ultrasound for 2-3 seconds, followed by a 2-3 second interval.

[0037] By adopting the above technical solution, the alternating working mode of ultrasound and intermittent operation can break up the agglomerates of photothermal conversion agent through ultrasonic vibration, while reducing excessive temperature rise of the system by using the intermittent time, providing a stable space for the dispersed photothermal conversion agent particles, reducing the probability of re-agglomeration, and finally achieving uniform dispersion of photothermal conversion agent in deionized water, ensuring its compatibility with asphalt-based composite emulsion and photothermal conversion performance.

[0038] The beneficial effects of this invention are as follows:

[0039] Petroleum asphalt can serve as a continuous phase base material, providing an initial waterproof barrier and ensuring proper wetting of the substrate; styrene-acrylate copolymer emulsions can form an interpenetrating network with petroleum asphalt, enhancing the elastic recovery of the coating; photothermal conversion agents can achieve a visible light-responsive photothermal effect, providing energy for the repair process; epoxidized soybean oil, through its epoxy groups, undergoes a ring-opening reaction with the terminal hydroxyl groups released after deacetylation of the dynamically borate ester bond hyperbranched self-healing agent, introducing a flexible long-chain structure, reducing the interfacial tension between the self-healing agent and asphalt and polymer emulsions, and improving compatibility with the coating system; cationic modified halloysite nanotubes can anchor other components in the system through electrostatic adsorption, improving the dispersion stability of each component and delaying water penetration; the maleic anhydride groups of maleic anhydride-grafted POE elastomer can interact with petroleum asphalt... The active groups such as carboxyl and hydroxyl groups in asphalt undergo esterification and amidation reactions, improving the interfacial adhesion between asphalt and polymers; emulsifiers promote the emulsification and dispersion of petroleum asphalt; dispersants ensure the stable dispersion of each solid component in the system and reduce agglomeration; rheology modifiers adjust the rheological properties of the coating and ensure morphological stability during construction; light stabilizers improve the coating's resistance to ultraviolet aging; amine buffers neutralize acidic products such as boric acid generated by the hydrolysis of borate ester bonds in the system, maintain the system's pH stability, and prevent the acidic environment from damaging the stability of dynamic borate ester bonds, thereby ensuring the long-term effectiveness of self-healing function; dehydrating agents control the moisture content of the system and improve the storage stability of the coating; deionized water provides a dispersion medium for each component and adjusts the solid content of the system to a suitable range.

[0040] Trimethylolpropane and 2,2-dimethylolbutyric acid can be used as monomers to construct a hyperbranched polyester backbone; p-toluenesulfonic acid can be used as a catalyst to promote efficient esterification; epoxidized soybean oil can be used to modify the product to improve its compatibility with the coating system; boric acid is used to introduce dynamic borate ester bonds, providing a core site for self-healing function; acetyl chloride can block terminal hydroxyl groups, reducing the risk of hydrolysis during storage; triethylamine can be used as an acid-binding agent to regulate the reaction system; anhydrous xylene provides a homogeneous reaction medium to ensure the smooth progress of the reaction; under visible light irradiation, the heat generated by the photothermal conversion agent can trigger the deprotection reaction of acetyl groups, releasing terminal hydroxyl groups, restoring the reversibility of dynamic borate ester bonds, and thus realizing the self-healing function. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Specific information on the raw materials used in the embodiments of this invention is shown in Table 1:

[0043] Table 1. Raw material names and sources

[0044] Components Specification source Petroleum asphalt Penetration 70 dmm, softening point 48℃ Maoming Zhengcheng Petrochemical Co., Ltd., Model 70# Styrene-acrylate copolymer emulsion Solid content 47%-49% Xiamen Kangdilong Trading Co., Ltd., Model TH8163 melamine 98% purity Shanghai Baishun Biotechnology Co., Ltd., CAS: 108-78-1 Ammonium dihydrogen phosphate 99% purity Shandong Zhengxing New Materials Co., Ltd., CAS: 7722-76-1 Citric acid Purity ≥ 99.0% Shandong Kexing Chemical Co., Ltd., CAS: 77-94-1 ethylenediamine 99.9% purity Liaocheng Tongda Chemical Co., Ltd., CAS: 109-89-7 Zinc acetate 99% purity Hubei Chengfeng Chemical Co., Ltd. Silane coupling agent KH-792 99% purity Wuhan Kanos Technology Co., Ltd. Anhydrous ethanol Analytical grade, purity ≥ 99.5% Sinopharm Chemical Reagent Co., Ltd. Trimethylolpropane 99% purity Shandong Shengteng Chemical Co., Ltd., CAS: 77-99-6 2,2-Dihydroxymethylbutyric acid 99% purity Wuhan Jiyesheng Chemical Co., Ltd., CAS: 10097-02-6 p-Toluenesulfonic acid 99% purity Shandong Xinheng Chemical Co., Ltd., CAS: 104-15-4 Epoxidized soybean oil 99% purity Wuhan Jiyesheng Chemical Co., Ltd., CAS: 8013-07-8 Boric acid Analytical grade, purity ≥ 99.5% Guangdong Daxiao Chemical Co., Ltd. Acetyl chloride 99% purity Shanghai Jiubang Chemical Co., Ltd. Triethylamine Purity ≥ 99.0% Shanghai Anpu Experimental Technology Co., Ltd., Research Reagents / CFEQ-4-520434-0005 Anhydrous xylene 99% purity Wuhan Kanos Technology Co., Ltd., CAS: 1330-20-7 Cationic modified halloysite nanotubes <![CDATA[The pipe diameter is 40 - 60 nm, the length is 500 - 800 nm, the specific surface area is ≥ 65 m 2 / g, and it is surface - modified with cetyltrimethylammonium bromide]]> Guangdong Jina New Materials Technology Co., Ltd. Maleic anhydride-grafted POE elastomer MAH grafting rate: 1.5%-2.0% Dongguan Zhangmutou Hongji Plastics & Chemicals Trading Company, CAS: 71342-87-5 emulsifier Sodium dodecylbenzenesulfonate, 99% purity Hubei Dongcao Chemical Technology Co., Ltd., CAS: 25155-30-0 Sodium dodecyl sulfate, 99% purity Hubei Wande Chemical Co., Ltd., CAS: 151-21-3 Sodium diisooctyl succinate sulfonate, active ingredient content: 72%-75%. Haian County Guoli Chemical Co., Ltd., CAS: 577-11-7 dispersant Sodium polycarboxylate, active ingredient: 45±1% Qingdao Gudao Chemical Materials Co., Ltd. Sodium polyacrylate, 99% purity Hubei Kewode Chemical Co., Ltd. rheology modifiers Organic bentonite, 99% purity Shenyang Elepx Chemical Co., Ltd. Hydrophobic fumed silica; specific surface area 150±15 m² / g, purity ≥99.8%, hydrophobicity value 50-70. Guangzhou Shenna Trading Co., Ltd., CAS: 112945-52-5; Polyamide wax, 99% purity, average particle size 5-8μm Kunshan Tangible Element Ultrafine Materials Co., Ltd. Light stabilizers Bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 98% purity Beijing Naphthalene Precipitation Biochemical Technology Co., Ltd. Bis(2,2,6,6-tetramethyl-4-piperidinyl)maleate, 98% purity Hubei Hongfuda Biotechnology Co., Ltd., CAS: 52829-07-9 Amine buffers N-Methyldiethanolamine, 99% purity Shandong Xinheng Chemical Co., Ltd. Triethanolamine, 99% purity Shandong Longhui Chemical Co., Ltd., CAS: 102-71-6 Diethanolamine, 99% purity Jinan Renyuan Chemical Co., Ltd., CAS: 111-42-2 Dehydrating agent Molecular sieve, model 3A Shandong Kaiou Chemical Technology Co., Ltd., CAS: 63231-69-6

[0045] Example 1:

[0046] This embodiment discloses a photocatalytic self-healing polymer asphalt waterproof coating. The raw materials for its preparation, by weight, include: 40 parts petroleum asphalt, 25 parts styrene-acrylate copolymer emulsion, 4 parts photothermal conversion agent, 8 parts dynamic borate ester bond hyperbranched self-healing agent, 6 parts cationic modified halloysite nanotubes, 3 parts maleic anhydride-grafted POE elastomer, 1 part sodium dodecylbenzenesulfonate, 0.5 parts sodium polycarboxylate, 1 part polyamide wax, 0.3 parts bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 0.5 parts diethanolamine, 0.8 parts molecular sieve, and 18 parts deionized water.

[0047] The raw materials for preparing the photothermal conversion agent, by weight, include: 10 parts melamine, 1 part ammonium dihydrogen phosphate, 2 parts citric acid, 1 part ethylenediamine, 0.5 parts zinc acetate, 0.3 parts silane coupling agent KH-792, 100 parts deionized water, and 50 parts anhydrous ethanol.

[0048] The preparation method of the photothermal conversion agent includes the following steps:

[0049] 1) Melamine and ammonium dihydrogen phosphate were placed in a ball mill and ground at 300 r / min for 20 min to ensure thorough mixing. The mixture was then transferred to a crucible and heated to 520℃ at 2℃ / min for 3.5 h. After cooling to 20℃, phosphorus-doped carbon nitride was obtained.

[0050] 2) Dissolve citric acid and ethylenediamine in half of the total amount of deionized water, stir at 200 r / min for 10 min to mix the system evenly, then adjust the pH to 6.5 with 0.08 mol / L sodium hydroxide solution, transfer to a high-pressure reactor, react at 175℃ for 5.5 h, cool to 20℃, and filter through a 0.20 μm filter membrane to obtain a carbon quantum dot solution;

[0051] 3) Disperse the phosphorus-doped carbon nitride obtained in step 1) in the remaining deionized water, add zinc acetate, and disperse for 30 min under ultrasonic power of 260 W and frequency of 32 kHz. Then add the carbon quantum dot solution obtained in step 2), stir at 200 r / min for 10 min to mix the system evenly, and then adjust the pH to 5.5 with 0.8 mol / L hydrochloric acid solution. Stir at 150 r / min for 1.5 h under 75℃ water bath conditions.

[0052] 4) Disperse the product obtained in step 3) in anhydrous ethanol, add silane coupling agent KH-792, and stir at 300 r / min for 3.5 h under reflux at 55 °C. Then centrifuge at 7600 r / min for 10 min, wash the precipitate three times with anhydrous ethanol, and dry it at -0.085 MPa and 60 °C for 10 h to obtain the photothermal conversion agent.

[0053] The raw materials for preparing the dynamic borate ester bond hyperbranching self-healing agent, by weight, include: 4 parts of trimethylolpropane, 8 parts of 2,2-dimethylolbutyric acid, 0.15 parts of p-toluenesulfonic acid, 15 parts of epoxidized soybean oil, 1.5 parts of boric acid, 1 part of acetyl chloride, 1.2 parts of triethylamine, 30 parts of anhydrous xylene, and 5 parts of deionized water.

[0054] The preparation method of the dynamic borate ester bond hyperbranched self-healing agent includes the following steps:

[0055] (1) Under nitrogen protection, trimethylolpropane, 2,2-dimethylolbutyric acid, p-toluenesulfonic acid and anhydrous xylene were added to the reactor in sequence. The mixture was stirred at 200 r / min for 15 min at 20 °C. Then, under nitrogen protection, the temperature was raised to 140 °C and stirred at 150 r / min for 6 h. When the acid value dropped to 20 mg KOH / g, the heating was stopped. The mixture was then distilled under reduced pressure for 40 min at a vacuum of -0.085 MPa and a temperature of 75 °C until no obvious distillate flowed out. The anhydrous xylene was recovered to obtain the hydroxyl-terminated hyperbranched polyester.

[0056] (2) Dissolve the end-hydroxyl hyperbranched polyester obtained in step (1) in anhydrous xylene at twice its mass, add boric acid, and stir at 150 r / min at 110°C for 4 h. After the reaction is completed, cool down to 10°C, and add acetyl chloride and triethylamine dropwise at a rate of 0.5 mL / min while stirring continuously at 150 r / min. After all the addition is completed, continue stirring at 10°C for 1.5 h.

[0057] (3) The product obtained in step (2) is heated to 80°C, epoxidized soybean oil and deionized water are added, and the reaction is carried out at 150 r / min for 2 h. Then, the solvent and low-boiling substances are removed by vacuum distillation for 2.5 h under vacuum conditions of -0.09 MPa and 80°C. Distillation is stopped when there is no obvious distillate to obtain the dynamic borate bond hyperbranching self-healing agent.

[0058] This embodiment also discloses a method for preparing a photocatalytic self-healing polymer bitumen waterproof coating, comprising the following steps:

[0059] S1. Heat petroleum asphalt to 130℃ to melt it, add maleic anhydride-grafted POE elastomer, shear and disperse it at 1000 r / min for 30 min, cool it to 110℃ and hold it for 10 min to obtain modified asphalt melt.

[0060] S2. Take 60% of the total amount of deionized water and heat it to 40℃. Add sodium dodecylbenzenesulfonate, sodium polycarboxylate, and bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate. Stir at 800 r / min for 10 min to dissolve and form a homogeneous aqueous phase. Divide the cationic modified halloysite nanotubes into three equal parts and add them to the aqueous phase in three portions, with an interval of 4 min between each addition. After each addition, disperse at 2000 r / min for 12 min to obtain a suspension.

[0061] S3. Add styrene-acrylate copolymer emulsion to step S2 and stir at 1200 r / min for 20 min. Then slowly add the modified asphalt melt obtained in step S1, while stirring at 2500 r / min. The feeding time is controlled at 15 min. After the addition is complete, continue stirring for 25 min to obtain asphalt-based composite emulsion.

[0062] S4. Add the photothermal conversion agent to the remaining deionized water and ultrasonically disperse it for 15 minutes at an ultrasonic power of 230W and a frequency of 36kHz. The working mode is: ultrasonic for 2 seconds, intermittent for 2 seconds, and repeat until the dispersion is completed. Add the asphalt-based composite emulsion obtained in step S3 and disperse it at 1500r / min for 30 minutes. Then, slowly add the dynamic borate ester bond hyperbranched self-healing agent at 35℃ and stir at 800r / min for 40 minutes. Then add the molecular sieve and continue stirring for 10 minutes.

[0063] S5. Stir the system obtained in step S4 at 600 r / min, add polyamide wax, continue stirring for 20 min, then add diethanolamine, continue stirring for 15 min, then vacuum degassing for 10 min under vacuum conditions of -0.085 MPa and 35℃, and filter through a 180 mesh sieve at normal pressure to obtain photocatalytic self-healing polymer asphalt waterproof coating.

[0064] Example 2:

[0065] This embodiment discloses a photocatalytic self-healing polymer asphalt waterproof coating. The raw materials for its preparation, by weight, include: 50 parts petroleum asphalt, 35 parts styrene-acrylate copolymer emulsion, 6 parts photothermal conversion agent, 12 parts dynamic borate ester bond hyperbranched self-healing agent, 10 parts cationic modified halloysite nanotubes, 8 parts maleic anhydride-grafted POE elastomer, 2 parts sodium dodecyl sulfate, 1.5 parts sodium polyacrylate, 3 parts hydrophobic fumed silica, 0.8 parts bis(2,2,6,6-tetramethyl-4-piperidinyl)maleate, 1 part triethanolamine, 1.5 parts molecular sieve, and 28 parts deionized water.

[0066] The raw materials for preparing the photothermal conversion agent, by weight, include: 15 parts melamine, 2 parts ammonium dihydrogen phosphate, 3 parts citric acid, 1.5 parts ethylenediamine, 1.0 part zinc acetate, 0.5 parts silane coupling agent KH-792, 150 parts deionized water, and 80 parts anhydrous ethanol.

[0067] The preparation method of the photothermal conversion agent includes the following steps:

[0068] 1) Melamine and ammonium dihydrogen phosphate were placed in a ball mill and ground at 400 r / min for 30 min to ensure thorough mixing. The mixture was then transferred to a crucible and heated to 550℃ at 4℃ / min for 4.5 h. After cooling to 25℃, phosphorus-doped carbon nitride was obtained.

[0069] 2) Dissolve citric acid and ethylenediamine in 1 / 3 of the total volume of deionized water, stir at 300 r / min for 15 min to mix the system evenly, then adjust the pH to 7.0 with 0.12 mol / L sodium hydroxide solution, transfer to a high-pressure reactor, react at 185℃ for 6.5 h, cool to 25℃, and filter through a 0.22 μm filter membrane to obtain a carbon quantum dot solution;

[0070] 3) Disperse the phosphorus-doped carbon nitride obtained in step 1) in the remaining deionized water, add zinc acetate, and disperse for 40 min under ultrasonic power of 300 W and frequency of 40 kHz. Then add the carbon quantum dot solution obtained in step 2), stir at 300 r / min for 15 min to mix the system evenly, and then adjust the pH to 6.0 with 1.2 mol / L hydrochloric acid solution. Stir at 250 r / min for 2.5 h under 85℃ water bath conditions.

[0071] 4) Disperse the product obtained in step 3) in anhydrous ethanol, add silane coupling agent KH-792, and stir at 400 r / min for 4.5 h under reflux at 65 °C. Then centrifuge at 8000 r / min for 15 min, wash the precipitate 4 times with anhydrous ethanol, and dry it at -0.095 MPa and 80 °C for 12 h to obtain the photothermal conversion agent.

[0072] The raw materials for preparing the dynamic borate ester bond hyperbranching self-healing agent, by weight, include: 6 parts of trimethylolpropane, 12 parts of 2,2-dimethylolbutyric acid, 0.25 parts of p-toluenesulfonic acid, 20 parts of epoxidized soybean oil, 2.5 parts of boric acid, 1.5 parts of acetyl chloride, 1.8 parts of triethylamine, 40 parts of anhydrous xylene, and 10 parts of deionized water.

[0073] The preparation method of the dynamic borate ester bond hyperbranched self-healing agent includes the following steps:

[0074] (1) Under nitrogen protection, trimethylolpropane, 2,2-dimethylolbutyric acid, p-toluenesulfonic acid and anhydrous xylene were added to the reactor in sequence. The mixture was stirred at 300 r / min for 25 min at 40 °C. Then, under nitrogen protection, the temperature was raised to 150 °C and stirred at 250 r / min for 8 h. When the acid value dropped to 30 mg KOH / g, the heating was stopped. The mixture was then distilled under reduced pressure for 60 min at a vacuum of -0.095 MPa and a temperature of 85 °C until no obvious distillate flowed out. The anhydrous xylene was recovered to obtain the hydroxyl-terminated hyperbranched polyester.

[0075] (2) Dissolve the end-hydroxyl hyperbranched polyester obtained in step (1) in anhydrous xylene in 3 times its mass, add boric acid, and stir at 250 r / min at 120°C for 5 h. After the reaction is completed, cool down to 15°C, and add acetyl chloride and triethylamine dropwise at a rate of 1.5 mL / min while stirring continuously at 250 r / min. After all the addition is completed, continue stirring at 15°C for 2.5 h.

[0076] (3) The product obtained in step (2) is heated to 90°C, epoxidized soybean oil and deionized water are added, and the reaction is carried out at 250 r / min for 3 h. Then, the solvent and low-boiling substances are removed by vacuum distillation for 3.5 h under vacuum conditions of -0.10 MPa and 90°C. Distillation is stopped when there is no obvious distillate to obtain the dynamic borate bond hyperbranching self-healing agent.

[0077] This embodiment also discloses a method for preparing a photocatalytic self-healing polymer bitumen waterproof coating, comprising the following steps:

[0078] S1. Heat petroleum asphalt to 140℃ to melt it, add maleic anhydride-grafted POE elastomer, shear and disperse it at a speed of 1200 r / min for 40 min, cool it down to 120℃ and hold it for 15 min to obtain modified asphalt melt.

[0079] S2. Take 70% of the total amount of deionized water and heat it to 50°C. Add sodium dodecyl sulfate, sodium polyacrylate, and bis(2,2,6,6-tetramethyl-4-piperidinyl)maleate. Stir at 1000 r / min for 15 min to dissolve and form a homogeneous aqueous phase. Divide the cationic modified halloysite nanotubes into three equal parts and add them to the aqueous phase in three separate additions, with a 5 min interval between each addition. After each addition, disperse at 2500 r / min for 15 min to obtain a suspension.

[0080] S3. Add styrene-acrylate copolymer emulsion to step S2 and stir at 1500 r / min for 25 min. Then slowly add the modified asphalt melt obtained in step S1, while stirring at 3000 r / min. The feeding time is controlled at 20 min. After the addition is complete, continue stirring for 30 min to obtain asphalt-based composite emulsion.

[0081] S4. Add the photothermal conversion agent to the remaining deionized water and ultrasonically disperse it for 20 minutes at an ultrasonic power of 250W and a frequency of 40kHz. The working mode is: ultrasonic for 3 seconds, intermittent for 3 seconds, and repeat until the dispersion is completed. Add the asphalt-based composite emulsion obtained in step S3 and disperse it at 1800r / min for 35 minutes. Then, slowly add the dynamic borate ester bond hyperbranched self-healing agent at 40℃ and stir at 1000r / min for 50 minutes. Then add the molecular sieve and continue stirring for 15 minutes.

[0082] S5. Stir the system obtained in step S4 at 800 r / min, add hydrophobic fumed silica, continue stirring for 25 min, then add triethanolamine, continue stirring for 20 min, then vacuum degassing for 15 min under vacuum conditions of -0.095 MPa and 40℃, and filter through a 200-mesh sieve at normal pressure to obtain a photocatalytic self-healing polymer asphalt waterproof coating.

[0083] Example 3:

[0084] This embodiment discloses a photocatalytic self-healing polymer asphalt waterproof coating. The raw materials for its preparation, by weight, include: 45 parts petroleum asphalt, 30 parts styrene-acrylate copolymer emulsion, 5 parts photothermal conversion agent, 10 parts dynamic borate ester bond hyperbranched self-healing agent, 8 parts cationic modified halloysite nanotubes, 5 parts maleic anhydride grafted POE elastomer, 1.5 parts sodium diisooctyl succinate sulfonate, 1 part sodium polycarboxylate, 2 parts organobentonite, 0.5 parts bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 0.7 parts N-methyldiethanolamine, 1.1 parts molecular sieve, and 23 parts deionized water.

[0085] The raw materials for preparing the photothermal conversion agent, by weight, include: 12 parts melamine, 1.5 parts ammonium dihydrogen phosphate, 2.5 parts citric acid, 1.2 parts ethylenediamine, 0.7 parts zinc acetate, 0.4 parts silane coupling agent KH-792, 125 parts deionized water, and 65 parts anhydrous ethanol.

[0086] The preparation method of the photothermal conversion agent includes the following steps:

[0087] 1) Melamine and ammonium dihydrogen phosphate were placed in a ball mill and ground at 350 r / min for 25 min to ensure thorough mixing. The mixture was then transferred to a crucible and heated to 535℃ at 3℃ / min for 4 h. After cooling to 22℃, phosphorus-doped carbon nitride was obtained.

[0088] 2) Dissolve citric acid and ethylenediamine in half of the total amount of deionized water, stir at 250 r / min for 12 min to mix the system evenly, then adjust the pH to 6.7 with 0.1 mol / L sodium hydroxide solution, transfer to a high-pressure reactor, react at 180℃ for 6 h, cool to 22℃, and filter through a 0.21 μm filter membrane to obtain a carbon quantum dot solution;

[0089] 3) Disperse the phosphorus-doped carbon nitride obtained in step 1) in the remaining deionized water, add zinc acetate, and disperse for 35 min under ultrasonic power of 280 W and frequency of 36 kHz. Then add the carbon quantum dot solution obtained in step 2), stir at 250 r / min for 12 min to mix the system evenly, and then adjust the pH to 5.7 with 1 mol / L hydrochloric acid solution. Stir at 200 r / min for 2 h under 80℃ water bath conditions.

[0090] 4) Disperse the product obtained in step 3) in anhydrous ethanol, add silane coupling agent KH-792, stir at 350 r / min for 4 h under reflux at 60 °C, then centrifuge at 7800 r / min for 12 min, wash the precipitate 4 times with anhydrous ethanol, and dry at -0.09 MPa and 70 °C for 11 h to obtain the photothermal conversion agent.

[0091] The raw materials for preparing the dynamic borate ester bond hyperbranching self-healing agent, by weight, include: 5 parts of trimethylolpropane, 10 parts of 2,2-dimethylolbutyric acid, 0.2 parts of p-toluenesulfonic acid, 17 parts of epoxidized soybean oil, 2 parts of boric acid, 1.2 parts of acetyl chloride, 1.5 parts of triethylamine, 35 parts of anhydrous xylene, and 7 parts of deionized water.

[0092] The preparation method of the dynamic borate ester bond hyperbranched self-healing agent includes the following steps:

[0093] (1) Under nitrogen protection, trimethylolpropane, 2,2-dimethylolbutyric acid, p-toluenesulfonic acid and anhydrous xylene were added to the reactor in sequence. The mixture was stirred at 250 r / min for 20 min at 30 °C. Then, under nitrogen protection, the temperature was raised to 145 °C and stirred at 200 r / min for 7 h. When the acid value dropped to 25 mg KOH / g, the heating was stopped. The mixture was then distilled under reduced pressure for 50 min at a vacuum of -0.09 MPa and a temperature of 80 °C until no obvious distillate flowed out. The anhydrous xylene was recovered to obtain the hydroxyl-terminated hyperbranched polyester.

[0094] (2) Dissolve the end-hydroxyl hyperbranched polyester obtained in step (1) in anhydrous xylene in 3 times its mass, add boric acid, and stir at 200 r / min at 115℃ for 4.5 h. After the reaction is completed, cool down to 12℃, and add acetyl chloride and triethylamine dropwise at a rate of 1 mL / min while stirring continuously at 200 r / min. After all the addition is completed, continue stirring at 12℃ for 2 h.

[0095] (3) The product obtained in step (2) is heated to 85°C, epoxidized soybean oil and deionized water are added, and the reaction is carried out at 200 r / min for 2.5 h. Then, the solvent and low-boiling substances are removed by vacuum distillation for 3 h under vacuum conditions of -0.095 MPa and 85°C. Distillation is stopped when there is no obvious distillate to obtain the dynamic borate bond hyperbranching self-healing agent.

[0096] This embodiment also discloses a method for preparing a photocatalytic self-healing polymer bitumen waterproof coating, comprising the following steps:

[0097] S1. Heat petroleum asphalt to 135℃ to melt it, add maleic anhydride-grafted POE elastomer, shear and disperse it at a speed of 1100 r / min for 35 min, cool it down to 115℃ and hold it for 12 min to obtain modified asphalt melt.

[0098] S2. Take 65% of the total amount of deionized water and heat it to 45℃. Add sodium diisooctyl succinate sulfonate, sodium polycarboxylate, and bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate. Stir at 900 r / min for 12 min to dissolve and form a homogeneous aqueous phase. Divide the cationic modified halloysite nanotubes into three equal parts and add them to the aqueous phase in three portions, with an interval of 4.5 min between each addition. After each addition, disperse at 2250 r / min for 13 min to obtain a suspension.

[0099] S3. Add styrene-acrylate copolymer emulsion to step S2 and stir at 1350 r / min for 22 min. Then slowly add the modified asphalt melt obtained in step S1, while stirring at 2750 r / min. The feeding time is controlled at 17 min. After the addition is complete, continue stirring for 27 min to obtain asphalt-based composite emulsion.

[0100] S4. Add the photothermal conversion agent to the remaining deionized water and ultrasonically disperse it for 17 minutes at an ultrasonic power of 240W and a frequency of 38kHz. The working mode is: ultrasonic for 3 seconds, intermittent for 3 seconds, and repeat until the dispersion is completed. Add the asphalt-based composite emulsion obtained in step S3 and disperse it at 1650r / min for 32 minutes. Then, slowly add the dynamic borate ester bond hyperbranched self-healing agent at 37℃ and stir at 900r / min for 45 minutes. Then add the molecular sieve and continue stirring for 12 minutes.

[0101] S5. Stir the system obtained in step S4 at 700 r / min, add organic bentonite, continue stirring for 22 min, then add N-methyldiethanolamine, continue stirring for 17 min, then vacuum degassing for 12 min under vacuum conditions of -0.09 MPa and 37℃, and filter through a 190 mesh sieve at normal pressure to obtain photocatalytic self-healing polymer asphalt waterproof coating.

[0102] Comparative Example 1:

[0103] A photocatalytic self-healing polymer asphalt waterproof coating and its preparation method are disclosed. The only difference between this coating and Example 3 is that no photothermal conversion agent is added, and deionized water of equal mass is used instead.

[0104] Comparative Example 2:

[0105] A photocatalytic self-healing polymer bitumen waterproof coating and its preparation method are disclosed. The only difference between this coating and Example 3 is that the dynamic borate bond hyperbranched self-healing agent is not added, and an equal mass of styrene-acrylate copolymer emulsion is used instead.

[0106] Comparative Example 3:

[0107] A photocatalytic self-healing polymer bitumen waterproof coating and its preparation method are disclosed. The only difference between this coating and Example 3 is that no cationic modified halloysite nanotubes are added.

[0108] Comparative Example 4:

[0109] A photocatalytic self-healing polymer bitumen waterproof coating and its preparation method are disclosed. The only difference between this coating and Example 3 is that maleic anhydride-grafted POE elastomer is replaced with ungrafted Dow POE 7387.

[0110] Comparative Example 5:

[0111] A photocatalytic self-healing polymer bitumen waterproof coating and its preparation method are disclosed. The only difference between this coating and Example 3 is that the temperature at which the dynamic borate ester bond hyperbranched self-healing agent is added in step S4 is 60°C.

[0112] Comparative Example 6:

[0113] A photocatalytic self-healing polymer bitumen waterproof coating and its preparation method are disclosed. The only difference between this coating and Example 3 is that no molecular sieve (dehydrating agent) is added.

[0114] Comparative Example 7:

[0115] A photocatalytic self-healing polymer asphalt waterproof coating and its preparation method are disclosed. The only difference between this coating and Example 3 is that organic bentonite (rheology modifier) ​​is not added, and talc powder of equal mass is used instead.

[0116] Comparative Example 8:

[0117] A photocatalytic self-healing polymer bitumen waterproof coating and its preparation method are disclosed. The only difference between this coating and Example 3 is that bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (hindered amine light stabilizer) is not added.

[0118] Comparative Example 9:

[0119] A photocatalytic self-healing polymer bitumen waterproof coating and its preparation method are disclosed. The only difference between this coating and Example 3 is that N-methyldiethanolamine (an amine buffer) is not added.

[0120] The waterproof coatings obtained in Examples 1-3 and Comparative Examples 1-9 were subjected to performance tests for tensile strength, elongation at break, bond strength, low-temperature flexibility, impermeability, photothermal conversion efficiency, self-healing efficiency, storage stability, water absorption, UV aging resistance, and water content of the system. The test methods and standards for each performance are as follows:

[0121] 1. Tensile strength and elongation at break testing

[0122] According to Clause 6.5 of the national standard "Polyurethane Waterproof Coating" (GB / T 19250-2013), a coating film with a thickness of 1.0±0.1mm was prepared by applying the coating to a polytetrafluoroethylene mold. After curing for 7 days under standard conditions (23±2℃, 50±5%RH), dumbbell-shaped specimens (compliant with GB / T 528-2009 Type I) were cut and tested using an electronic universal testing machine at a tensile rate of 500±20mm / min. The arithmetic mean of 5 specimens was recorded.

[0123] 2. Bond strength test

[0124] According to Clause 7.6 of the national standard "Test Methods for Waterproof Coatings for Buildings" (GB / T 16777-2008), the coating was applied to the surface of a standard concrete slab (70mm×70mm×20mm), and the dry film thickness was controlled at 100±10μm. After 14 days of standard curing, a figure-eight tensile test was conducted with a tensile rate of 5mm / min.

[0125] 3. Low-temperature flexibility testing

[0126] According to Chapter 13 of the national standard "Test Methods for Waterproof Coatings for Buildings" (GB / T 16777-2008), the coating was applied to the surface of the aluminum plate, and the dry film thickness was controlled at 1.0±0.1mm. After standard curing for 7 days, the plate was placed in a low temperature chamber at -20±2℃ for 2 hours. The plate was then bent 180° around a round bar of specified diameter (φ5mm, φ10mm, φ15mm) within 2-3 seconds. The plate was then observed for cracking using a 5x magnifying glass.

[0127] 4. Impermeability test

[0128] According to Chapter 15 of the national standard "Test Methods for Waterproof Coatings for Buildings" (GB / T 16777-2008), the coating was applied to the surface of the aluminum plate, and the dry film thickness was controlled at 1.5±0.1mm. After standard curing for 7 days, the plate was placed in an impermeability tester and subjected to a water pressure of 0.30±0.02MPa for 30 minutes. The back side was then observed for any water seepage.

[0129] 5. Photothermal conversion efficiency testing

[0130] Referring to the enterprise standard "Test Method for Performance of Photothermal Conversion Materials", 0.5g of photothermal conversion agent was dispersed in 5mL of ethanol and coated onto a glass slide. After the solvent evaporated, it was placed under a simulated solar light source (AM 1.5G, 100mW / cm²). 2 Irradiate for 30 minutes, record temperature changes using an infrared thermal imager, and calculate photothermal conversion efficiency η=(ΔT×m×C) / (I×S×t)×100%, where ΔT is the temperature rise, m is the sample mass, C is the specific heat capacity, I is the light intensity, S is the irradiated area, and t is the time.

[0131] 6. Self-repair efficiency test

[0132] A 2 mm thick coating was prepared, and a 0.5 mm wide through-crack was cut with a blade. The coatings were then placed under standard illumination conditions (simulating sunlight AM 1.5G, 100 mW / cm²). 2 After irradiation for 30 minutes, cure for 21 days in a standard environment (23±2℃, 50±5% RH), or directly in natural indoor light (light intensity 10-30mW / cm²). 2 After 21 days of curing, the post-repair strength was determined according to the tensile strength test method. The self-healing efficiency was calculated using the following formula:

[0133] Repair efficiency η(%) = (Tensile strength after repair / Initial tensile strength) × 100%

[0134] 7. Storage stability test

[0135] According to the national standard "Test Method for Storage Stability of Coatings" (GB / T 6753.3-1986), approximately 500 mL of sample was sealed and stored in an oven at 50±2℃ for 7 days. After being removed and cooled to room temperature, the viscosity before and after storage was measured (using a Stormer viscometer, ASTM D562), and the viscosity change rate was calculated.

[0136] Viscosity change rate (%) = (Viscosity after storage - Viscosity before storage) / Viscosity before storage × 100%

[0137] At the same time, observe whether phenomena such as stratification, sedimentation, and flocculation occur.

[0138] 8. Water absorption rate test

[0139] According to Chapter 14 of the national standard "Test Methods for Waterproof Coatings for Buildings" (GB / T 16777-2008), the coating film was prepared into 30mm×30mm×2mm specimens. After standard curing for 7 days, the specimens were weighed (m1), immersed in deionized water at 23±2℃ for 168 hours, removed, wiped dry, and weighed (m2). The formula for calculating the water absorption rate is:

[0140] Water absorption rate (%) = (m2 - m1) / m1 × 100%

[0141] 9. UV aging performance testing

[0142] According to the national standard "Aging Test Method for Building Waterproofing Materials" (GB / T 18244-2000), the coating was irradiated in a xenon arc lamp aging chamber for 1000 hours. The parameters were set as follows: black panel temperature 63±2℃, relative humidity 50±5%, and irradiation intensity 0.51W / m². 2 @340nm. Tensile properties were tested after aging, and the performance retention rate was calculated.

[0143] 10. System water content detection

[0144] According to the Karl Fischer coulometric method (GB / T 6283-2008), the moisture content in the coating sample was directly determined using a Karl Fischer moisture analyzer with an accuracy of 0.001%.

[0145] The results are shown in Tables 2 and 3.

[0146] Table 2. Basic mechanical and self-healing properties of the waterproof coatings obtained in Examples 1-3 and Comparative Examples 1-9 (21-day repair cycle)

[0147] Group Tensile strength (MPa) Elongation at break (%) Low-temperature flexibility (-20℃) Bond strength (MPa) Repair efficiency η (%), standard illumination* Repair efficiency η (%), indoor natural light Example 1 4.2 285 No cracks 1.45 58.5 28.5 Example 2 4.6 315 No cracks 1.60 62.8 32.4 Example 3 5.0 340 No cracks 1.75 67.5 36.8 Comparative Example 1 4.7 320 No cracks 1.70 32.5 No repair Comparative Example 2 3.8 250 No cracks 1.25 5.8 No repair Comparative Example 3 3.9 275 No cracks 1.35 48.5 22.5 Comparative Example 4 4.4 295 No cracks 1.30 52.5 25.8 Comparative Example 5 3.5 280 No cracks 1.45 45.2 20.5 Comparative Example 6 3.8 240 No cracks 1.25 35.5 12.8 Comparative Example 7 4.3 290 minor cracks 1.55 56.8 27.5 Comparative Example 8 4.0 280 No cracks 1.48 55.5 26.5 Comparative Example 9 4.5 300 No cracks 1.50 55.5 26.5

[0148] Note: Standard lighting conditions: Simulated solar light source (AM 1.5G, 100mW / cm²) 2 Irradiate for 30 minutes.

[0149] Table 3. Photothermal conversion and durability properties of the waterproof coatings obtained in Examples 1-3 and Comparative Examples 1-9

[0150] Group Photothermal temperature rise ΔT (°C, 30 min) Thermal aging strength retention rate (%, 168h / 504h) Elongation retention rate after UV aging (%, 1000h) Water absorption rate (%, 168h) Water content during storage (%, 180 days) Storage stability (viscosity change rate, 7 days / 50℃) Example 1 18.5 85.2 / 78.5 82.3 3.8 0.28 8.5 Example 2 21.2 88.5 / 82.3 85.6 3.2 0.25 7.8 Example 3 24.5 91.2 / 85.6 88.5 2.8 0.22 7.2 Comparative Example 1 6.5 87.3 / 81.5 83.2 4.2 0.30 10.5 Comparative Example 2 23.8 72.5 / 58.2 68.5 5.5 0.32 12.8 Comparative Example 3 19.8 82.5 / 71.2 78.5 6.2 0.35 15.2 Comparative Example 4 20.5 85.2 / 76.8 80.2 3.5 0.28 10.2 Comparative Example 5 20.2 86.2 / 78.5 79.8 4.5 0.45 18.5 Comparative Example 6 15.8 68.5 / 42.5 58.2 5.8 0.62 25.5 Comparative Example 7 21.8 88.2 / 81.5 84.2 5.2 0.25 8.5 Comparative Example 8 23.2 89.5 / 82.8 85.5 3.5 0.25 9.2 Comparative Example 9 23.5 90.5 / 84.2 87.5 3.2 0.25 15.8

[0151] Note: The heat aging conditions are constant temperature aging in an oven at 50±2℃.

[0152] Using Example 3 as the control group, the performance differences and causes of Comparative Examples 1-9 are analyzed as follows:

[0153] Comparative Example 1 (without photothermal conversion agent): The repair efficiency decreased to 32.5%, and the photothermal temperature rise was only 6.5℃, a 73.5% reduction compared to 24.5℃ in Example 3. The test results show that the photothermal effect can significantly accelerate the deprotection reaction of acetyl groups. At room temperature (23±2℃), the acetyl hydrolysis half-life is approximately 45-60 days, and the repair efficiency after 21 days is only 32.5%, a phenomenon consistent with Arrhenius kinetics. Compared to 67.5% in Example 3, the repair efficiency decreased by 35 percentage points, a reduction of 51.9%, and the photothermal effect increased the acetyl hydrolysis rate by 2.1 times (the 21-day repair efficiency increased from 32.5% to 67.5%). Natural light cannot provide sufficient heat to trigger the acetyl deprotection reaction, therefore there is no self-repair effect.

[0154] Comparative Example 2 (without dynamic borate ester bond hyperbranched self-healing agent): The repair efficiency decreased to 5.8%, and the water absorption rate increased to 5.5%, an increase of 96.4% compared to 2.8% in Example 3. The test results show that this self-healing agent is the main component of chemical repair. Compared with Example 3, the repair efficiency decreased by 61.7 percentage points, a decrease of 91.4%. This 5.8% repair efficiency should be the "physical healing rate," which originates from the thermoplastic flow of asphalt particles, indicating that the healing ability is limited without a chemical repair mechanism.

[0155] Comparative Example 3 (without cationic modified halloysite nanotubes): Repair efficiency was 48.5%, and water absorption increased to 6.2%, a 121% improvement compared to 2.8% in Example 3. The test results showed the nano-reinforcing and moisture-retarding effects of the cationic modified halloysite nanotubes; their tubular structure reduced the water penetration rate by 40-60%, and the migration efficiency of the repair agent decreased by 28.1% without this component. The bond strength decreased from 1.75 MPa to 1.35 MPa, a reduction of 22.9%, demonstrating a significant interfacial strengthening effect.

[0156] Comparative Example 4 (using ungrafted POE): Tensile strength decreased from 5.0 MPa to 4.4 MPa, and the repair efficiency was 52.5% (a decrease of 15 percentage points). Due to the lack of maleic anhydride functional groups, the interfacial chemical bonding ability was weak, and the repair agent was easily lost. The bond strength decreased from 1.75 MPa to 1.30 MPa, a decrease of 25.7%, and the test results showed that maleic anhydride grafting played a decisive role in interfacial bonding. However, the elongation at break remained at 295%, indicating that the flexibility contribution of the POE backbone was still retained.

[0157] Comparative Example 5 (Self-healing agent added at excessively high temperature): Repair efficiency was 45.2%, water content during storage reached 0.45%, an increase of 104.5% compared to 0.22% in Example 3, and the attenuation rate was 18.5%, an increase of 157% compared to 7.2% in Example 3. The test results showed that the addition temperature of 60℃ caused premature hydrolysis of acetyl groups, resulting in a significant decrease in storage stability. The excessively high addition temperature (60℃) caused premature hydrolysis of acetyl groups, partially activating the self-healing agent during preparation, leading to an attenuation rate of 18.5% during storage. Tensile strength decreased to 3.5 MPa; the high temperature caused premature cross-linking of the self-healing agent, reducing the system's flexibility and tensile strength.

[0158] Comparative Example 6 (without molecular sieve dehydrating agent): The photothermal temperature dropped to 15.8℃, the repair efficiency was 35.5%, and the water content during storage reached 0.62%, an increase of 182% compared to 0.22% in Example 3. The attenuation rate was 25.5%, an increase of 254% compared to 7.2% in Example 3. The 35.5% decrease in photothermal efficiency was due to the aggregation caused by water adsorbed on the surface of the heterojunction. The test results showed that the molecular sieve played a key role in maintaining low water content. When the water content was >0.5%, the cumulative concentration of acetic acid in the system led to pH <5.0, and the borate ester bonds underwent irreversible hydrolysis (the stable pH range of borate ester bonds is 5.5-8.0).

[0159] Comparative Example 7 (without organobentonite rheology modifier): Sagging resistance decreased, sagging occurred during application, and the coating thickness was uneven. Slight cracks appeared in the low-temperature flexibility test, indicating that organobentonite contributed to the coating's low-temperature crack resistance. However, the repair efficiency of 56.8% was only 15.9% lower than that of Example 3 (67.5%), suggesting that the rheology modifier has a limited direct impact on self-healing function, primarily improving workability.

[0160] Comparative Example 8 (without hindered amine light stabilizer): After 500 hours of UV aging, the elongation retention rate was 85.5%, which was 3 percentage points lower than the 88.5% in Example 3. The photothermal temperature rise of 23.2℃ was basically the same as the 24.5℃ in Example 3, indicating that the light stabilizer mainly protects the organic components rather than the photothermal conversion agent.

[0161] Comparative Example 9 (without N-methyldiethanolamine buffer): The storage degradation rate was 15.8%, an increase of 119% compared to 7.2% in Example 3. The test results show that N-methyldiethanolamine inhibits the degradation of borate ester bonds by neutralizing acidic hydrolysis products. However, the repair efficiency was 55.5%, a decrease of 17.8% compared to 67.5% in Example 3, indicating that acetylation blocking is the main protective mechanism, and the buffer is an auxiliary mechanism.

[0162] In summary, photothermal conversion agents can achieve photothermal effects responsive to visible light, providing energy for the repair process; epoxidized soybean oil undergoes a ring-opening reaction with the terminal hydroxyl groups released after deacetylation of the hyperbranched self-healing agent via epoxy groups, introducing a flexible long-chain structure, reducing the interfacial tension between the self-healing agent and asphalt and polymer emulsions, and improving compatibility with coating systems; cationic modified halloysite nanotubes can anchor other components in the system through electrostatic adsorption, improving the dispersion stability of each component and delaying water penetration; the maleic anhydride groups of maleic anhydride-grafted POE elastomer can undergo esterification and amidation reactions with active groups such as carboxyl and hydroxyl groups in petroleum asphalt, improving the interfacial adhesion between asphalt and polymers.

[0163] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. 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. Such 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 photocatalytic self-healing polymer bitumen waterproof coating, characterized in that, The raw materials for its preparation, by weight, include: 40-50 parts petroleum asphalt, 25-35 parts styrene-acrylate copolymer emulsion, 4-6 parts photothermal conversion agent, 8-12 parts dynamic borate ester bond hyperbranched self-healing agent, 6-10 parts cationic modified halloysite nanotubes, 3-8 parts maleic anhydride grafted POE elastomer, 1-2 parts emulsifier, 0.5-1.5 parts dispersant, 1-3 parts rheology modifier, 0.3-0.8 parts light stabilizer, 0.5-1.0 parts amine buffer, 0.8-1.5 parts dehydrating agent, and 18-28 parts deionized water.

2. The photocatalytic self-healing polymer bitumen waterproof coating according to claim 1, characterized in that, The emulsifier is one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium diisooctyl succinate sulfonate; the dispersant is one of sodium polycarboxylate or sodium polyacrylate; and the rheology modifier is one or more of organobentonite, hydrophobic fumed silica, and polyamide wax.

3. The photocatalytic self-healing polymer bitumen waterproof coating according to claim 1, characterized in that, The light stabilizer is one of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and bis(2,2,6,6-tetramethyl-4-piperidinyl) maleate; the amine buffer is one or more of N-methyldiethanolamine, triethanolamine, and diethanolamine; and the dehydrating agent is a molecular sieve.

4. The photocatalytic self-healing polymer bitumen waterproof coating according to claim 1, characterized in that, The raw materials for preparing the photothermal conversion agent, by weight, include: 10-15 parts melamine, 1-2 parts ammonium dihydrogen phosphate, 2-3 parts citric acid, 1-1.5 parts ethylenediamine, 0.5-1.0 parts zinc acetate, 0.3-0.5 parts silane coupling agent KH-792, 100-150 parts deionized water, and 50-80 parts anhydrous ethanol.

5. The photocatalytic self-healing polymer bitumen waterproof coating according to claim 4, characterized in that, The preparation method of the photothermal conversion agent includes the following steps: 1) Place melamine and ammonium dihydrogen phosphate in a ball mill and grind them at a speed of 300-400 r / min for 20-30 min to ensure they are thoroughly mixed. Then transfer the mixture to a crucible and heat it to 520-550℃ at a speed of 2-4℃ / min. Hold the temperature for 3.5-4.5 h and cool it to 20-25℃ to obtain phosphorus-doped carbon nitride. 2) Dissolve citric acid and ethylenediamine in 1 / 2-1 / 3 of the total volume of deionized water, stir at 200-300 r / min for 10-15 min to mix the system evenly, then adjust the pH to 6.5-7.0 with 0.08-0.12 mol / L sodium hydroxide solution, transfer to a high-pressure reactor, react at 175-185℃ for 5.5-6.5 h, cool to 20-25℃, and filter through a 0.20-0.22 μm filter membrane to obtain a carbon quantum dot solution; 3) Disperse the phosphorus-doped carbon nitride obtained in step 1) in the remaining deionized water, add zinc acetate, and disperse for 30-40 min under ultrasonic power of 260-300 W and frequency of 32-40 kHz. Then add the carbon quantum dot solution obtained in step 2), stir at 200-300 r / min for 10-15 min to mix the system evenly, and then adjust the pH to 5.5-6.0 with 0.8-1.2 mol / L hydrochloric acid solution. Stir the reaction at 150-250 r / min for 1.5-2.5 h under water bath conditions of 75-85℃. 4) Disperse the product obtained in step 3) in anhydrous ethanol, add silane coupling agent KH-792, and stir the reaction at 300-400 r / min for 3.5-4.5 h under reflux at 55-65 °C. Then centrifuge at 7600-8000 r / min for 10-15 min, wash the precipitate with anhydrous ethanol 3-4 times, and dry it under vacuum of -0.085~-0.095 MPa and temperature of 60-80 °C for 10-12 h to obtain the photothermal conversion agent.

6. The photocatalytic self-healing polymer bitumen waterproof coating according to claim 1, characterized in that, The raw materials for preparing the dynamic borate ester bond hyperbranching self-healing agent, by weight, include: 4-6 parts of trimethylolpropane, 8-12 parts of 2,2-dimethylolbutyric acid, 0.15-0.25 parts of p-toluenesulfonic acid, 15-20 parts of epoxidized soybean oil, 1.5-2.5 parts of boric acid, 1.0-1.5 parts of acetyl chloride, 1.2-1.8 parts of triethylamine, 30-40 parts of anhydrous xylene, and 5-10 parts of deionized water.

7. The photocatalytic self-healing polymer bitumen waterproof coating according to claim 6, characterized in that, The preparation method of the dynamic borate ester bond hyperbranched self-healing agent includes the following steps: (1) Under nitrogen protection, trimethylolpropane, 2,2-dimethylolbutyric acid, p-toluenesulfonic acid and anhydrous xylene are added to the reaction vessel in sequence. The mixture is stirred at 200-300 r / min for 15-25 min at 20-40℃. Then, under nitrogen protection, the temperature is raised to 140-150℃ and stirred at 150-250 r / min for 6-8 h. When the acid value drops to 20-30 mg KOH / g, the heating is stopped. The mixture is then distilled under reduced pressure at a vacuum of -0.085~-0.095 MPa and a temperature of 75-85℃ for 40-60 min until no obvious distillate flows out. The anhydrous xylene is recovered to obtain the hydroxyl-terminated hyperbranched polyester. (2) Dissolve the end-hydroxyl hyperbranched polyester obtained in step (1) in anhydrous xylene in 2-3 times its mass, add boric acid, and stir at 150-250 r / min at 110-120℃ for 4-5 h. After the reaction is completed, cool down to 10-15℃, and add acetyl chloride and triethylamine dropwise at a rate of 0.5-1.5 mL / min while stirring continuously at 150-250 r / min. After all the addition is completed, continue stirring at 10-15℃ for 1.5-2.5 h. (3) Heat the product obtained in step (2) to 80-90℃, add epoxidized soybean oil and deionized water, react at 150-250r / min for 2-3h, and then distill under reduced pressure at a vacuum of -0.09~-0.10MPa and a temperature of 80-90℃ for 2.5-3.5h to remove solvent and low-boiling substances. Stop distillation when there is no obvious distillate to obtain the dynamic borate bond hyperbranching self-repairing agent.

8. A method for preparing a photocatalytic self-healing polymer bitumen waterproof coating according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Heat petroleum asphalt to 130-140℃ to melt it, add maleic anhydride-grafted POE elastomer, shear and disperse it at a speed of 1000-1200r / min for 30-40min, cool it down to 110-120℃ and hold it for 10-15min to obtain modified asphalt melt. S2. Take 60%-70% of the total amount of deionized water and heat it to 40-50℃. Add emulsifier, dispersant and light stabilizer, and stir to dissolve for 10-15 minutes at 800-1000 r / min. Add the cationic modified halloysite nanotubes to the system in three batches and disperse them at 2000-2500 r / min for 36-45 minutes to obtain a suspension. S3. Add styrene-acrylate copolymer emulsion to step S2 and stir at 1200-1500 r / min for 20-25 min. Then slowly add the modified asphalt melt obtained in step S1, while stirring at 2500-3000 r / min. The addition time is controlled at 15-20 min. After the addition is complete, continue stirring for 25-30 min to obtain asphalt-based composite emulsion. S4. Add the photothermal conversion agent to the remaining deionized water and ultrasonically disperse it for 15-20 minutes under ultrasonic power of 230-250W and frequency of 36-40kHz. Add the asphalt-based composite emulsion obtained in step S3 and disperse it for 30-35 minutes at 1500-1800r / min. Then, slowly add the dynamic borate ester bond hyperbranched self-healing agent at 35-40℃ and stir at 800-1000r / min for 40-50 minutes. Add the dehydrating agent and continue stirring for 10-15 minutes. S5. Stir the system obtained in step S4 at 600-800 r / min, add the rheology modifier, and continue stirring for 20-25 min. Then add the amine buffer and continue stirring for 15-20 min. Then, vacuum degassing is performed for 10-15 min under vacuum conditions of -0.085~-0.095 MPa and 35-40℃. After filtration through a 180-200 mesh sieve at normal pressure, the photocatalytic self-healing polymer asphalt waterproof coating is obtained.

9. The preparation method of the photocatalytic self-healing polymer bitumen waterproof coating according to claim 8, characterized in that, In step S2, the cationic modified halloysite nanotubes added three times are of equal mass, and each addition should be spaced 4-5 minutes apart.

10. The preparation method of the photocatalytic self-healing polymer bitumen waterproof coating according to claim 8, characterized in that, In step S4, the ultrasound working mode is: ultrasound for 2-3 seconds, followed by a 2-3 second interval.