Waterproof paint for external wall insulation board and preparation method thereof

Abstract

The application discloses a waterproof paint for external wall insulation board and a preparation method thereof, and belongs to the technical field of chemical coatings. The preparation method comprises the following steps: mixing and stirring sodium dodecyl sulfate, an emulsifier, modified sodium lignosulfonate, methyl methacrylate, butyl acrylate, methacrylic acid and methyl vinyl dimethoxysilane to obtain a pre-emulsion, and then adding and stirring ammonium persulfate to obtain an acrylic emulsion; and mixing and stirring the acrylic emulsion, deionized water, a composite modified filler, a leveling agent and a defoaming agent to obtain the waterproof paint. The waterproof paint can construct a uniform and dense hydrophobic interface on the surface of a coating, effectively improves the hydrophobic and waterproof capacity of the coating, and has good waterproof protection stability.

Description

Technical Field

[0001] This invention relates to the field of chemical coatings technology, specifically to a waterproof paint for exterior wall insulation boards and its preparation method. Background Technology

[0002] As a key protective material in building exterior wall insulation systems, exterior wall insulation and waterproofing paint is constantly exposed to complex outdoor conditions such as rainwater erosion, wind and sand abrasion, and alternating hot and cold temperatures. Therefore, it requires extremely high comprehensive performance in terms of hydrophobicity, waterproofing, mechanical abrasion resistance, moisture permeability, and microscopic self-healing. Currently, traditional exterior wall waterproofing coatings generally suffer from single-performance characteristics and difficulty in synergistically matching various indicators, resulting in insufficient overall service stability and failing to meet the practical application requirements for long-term protection of building exterior walls.

[0003] Existing waterproof coatings mostly use conventional inorganic fillers such as nano-silica, which have a simple structure and lack a multi-level porous framework. This results in poor compatibility with organic resin matrices, making it difficult to form a dense and stable hydrophobic interface, leading to poor waterproofing performance. Furthermore, the lack of a reinforcing skeleton results in weak abrasion resistance. Disordered inorganic fillers can also damage the internal microporous structure of the coating, hindering water vapor conduction and failing to achieve a balance between waterproofing and breathability. Moreover, the lack of a dynamic response structure means the coating cannot self-repair after microscopic damage. Traditional stearic acid modification grafting methods exhibit weak bonding stability and poor hydrophobic durability, easily forming defects within the coating and failing to construct a dynamic and reversible interface.

[0004] Invention patent CN103525285B discloses a thin-coat polyurethane waterproof paint that relies on polyurethane resin and conventional inorganic fillers to form a film, achieving basic waterproofing and aging-resistant protection. However, this waterproof paint has a fixed structure and lacks a dynamically reversible cross-linking structure. When the coating is subjected to wind erosion and temperature deformation, microscopic scratches and cracks develop, it cannot self-repair, leading to problems such as damage, water seepage, peeling, and aging after long-term use. Furthermore, the coating is entirely sealed, lacking regular, interconnected microporous ventilation channels, making it difficult to drain moisture accumulated inside the wall, easily causing wall dampness, coating blistering, and peeling.

[0005] Therefore, providing an exterior wall insulation and waterproofing paint with good overall performance that can synergistically combine hydrophobicity and breathability is an important problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the problems in the prior art, this invention provides a waterproof paint for exterior wall insulation boards and its preparation method. Specifically, the technical solution of this invention includes the following: A method for preparing a waterproof paint for exterior wall insulation boards, the method comprising the following steps: Sodium dodecyl sulfate, emulsifier, modified sodium lignosulfonate, methyl methacrylate, butyl acrylate, methacrylic acid and methyl vinyl dimethoxysilane are mixed and stirred to obtain a pre-emulsion, and then ammonium persulfate is added and stirred to obtain an acrylic emulsion. The waterproof paint is prepared by mixing and stirring acrylic emulsion, deionized water, composite modified filler, leveling agent and defoamer.

[0007] Furthermore, the emulsifier is emulsifier DNS-86.

[0008] Furthermore, the preparation method of the modified sodium lignosulfonate includes the following steps: Sodium lignosulfonate, triethylamine, and stearoyl chloride were mixed and stirred to react, yielding the first intermediate. Modified sodium lignin sulfonate was prepared by mixing and stirring the first intermediate with silane coupling agent KH-570.

[0009] Furthermore, the weight ratio of sodium lignosulfonate, triethylamine, and stearoyl chloride is 1.0:0.8~1.2:0.4~0.6.

[0010] Furthermore, the conditions for the mixed stirring reaction of sodium lignosulfonate, triethylamine and stearoyl chloride include a reaction temperature of 50-60°C, a reaction speed of 400-500 r / min, and a reaction time of 4-5 h.

[0011] Furthermore, the weight ratio of the first intermediate to the silane coupling agent KH-570 is 0.8~1.2:0.18~0.28.

[0012] Furthermore, the conditions for the mixing and stirring reaction of the first intermediate and the silane coupling agent KH-570 include a reaction temperature of 55~65℃, a reaction pH of 4.0~4.5, and a reaction time of 6~8h.

[0013] Furthermore, the mixing conditions for sodium dodecyl sulfate, emulsifier, modified sodium lignosulfonate, methyl methacrylate, butyl acrylate, methacrylic acid and methyl vinyl dimethoxysilane include a mixing speed of 400~500 r / min and a mixing time of 30~50 min.

[0014] Further, the weight ratio of sodium dodecyl sulfate, emulsifier, modified sodium lignosulfonate, methyl methacrylate, butyl acrylate, methacrylic acid, methyl vinyl dimethoxysilane and ammonium persulfate is 1.0~1.5:0.8~1.2:1.0~1.6:35~40:25~30:2~3:5~8:0.4~0.6.

[0015] Furthermore, the conditions for adding ammonium persulfate and stirring the reaction include a reaction temperature of 85-95°C and a reaction time of 4-5 hours.

[0016] Furthermore, the solid content of the acrylic emulsion is 45 wt%.

[0017] Furthermore, the preparation method of the composite modified filler includes the following steps: A composite organic framework was obtained by mixing and stirring zinc nitrate hexahydrate, 2-methylimidazole and multi-walled carbon nanotubes. A hydrophobic intermediate was obtained by mixing and stirring octadecyl phosphoric acid and a complex organic framework. A complex intermediate was obtained by mixing and stirring a hydrophobic intermediate with dopamine hydrochloride. A composite modified filler was prepared by mixing and stirring terephthalic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide, 2-aminobenzylimidazole and a composite intermediate.

[0018] Furthermore, the weight ratio of zinc nitrate hexahydrate, 2-methylimidazole, and multi-walled carbon nanotubes is 1.0:4.8~5.2:0.06~0.12.

[0019] Furthermore, the conditions for the mixed and stirred reaction of zinc nitrate hexahydrate, 2-methylimidazole and multi-walled carbon nanotubes include a reaction pH of 7.8-8.5, a reaction temperature of 130-140℃ and a reaction time of 12-14h.

[0020] Furthermore, the weight ratio of the octadecyl phosphoric acid to the composite organic framework is 1.5~2.5:0.3~0.5.

[0021] Furthermore, the conditions for the mixing and stirring reaction of the octadecyl phosphoric acid and the composite organic framework include a reaction temperature of 45-55°C and a reaction time of 12-16 h.

[0022] Furthermore, the weight ratio of the hydrophobic intermediate to dopamine hydrochloride is 1.0~1.2:0.08~0.15.

[0023] Furthermore, the conditions for the mixed stirring reaction of the hydrophobic intermediate and dopamine hydrochloride include a reaction pH of 8.0-8.8, a reaction temperature of 30-38°C, and a reaction time of 10-14 hours.

[0024] Further, the weight ratio of terephthalic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide, 2-aminobenzylimidazole and the complex intermediate is 0.8~0.8:0.35~0.55:0.15~0.25:1.0~1.6:8~10.

[0025] Furthermore, the conditions for the mixing and stirring reaction of terephthalic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide, 2-aminobenzylimidazole and the complex intermediate include a reaction temperature of 50-70°C and a reaction time of 5-7 h.

[0026] Furthermore, the leveling agent is Rohm and Haas leveling agent RM-2020.

[0027] Furthermore, the defoamer is Evonik Surfynol DF-110D.

[0028] Furthermore, the weight ratio of the acrylic emulsion, deionized water, composite modified filler, leveling agent and defoamer is 100:15~25:7~9:0.3~0.6:0.2~0.5.

[0029] Furthermore, the mixing conditions for the acrylic emulsion, deionized water, composite modified filler, leveling agent and defoamer include a stirring speed of 300~400 r / min and a stirring time of 15~25 min.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention employs a multi-step chemical modification process to prepare a composite modified filler, improving upon the existing problems of poor wear and weather resistance, easy degradation of hydrophobic properties after UV aging, and difficulty in balancing waterproof and breathable properties in external wall insulation and waterproof paints. This invention uses a ZIF-8 organic framework containing multi-walled carbon nanotubes as a substrate, and sequentially performs hydrophobic grafting of octadecylphosphonic acid, polydopamine coating, and gradient grafting modification of functional monomers to construct a composite filler system with porous channels and gradient mechanical properties. The modified gradient structure can optimize the mechanical properties of the coating, helping to improve the coating's ability to resist outdoor wind and sand erosion, external friction, and temperature fluctuations, and slowing down the rate of hydrophobic structure failure. Based on the composite system of carbon nanotubes and polydopamine, the coating can possess a certain UV shielding effect, weakening the performance degradation caused by outdoor aging. Meanwhile, the through-hole structure of the filler can achieve gas-liquid differential permeation, which can block liquid rainwater from seeping into the insulation board, while also facilitating the drainage of gaseous water vapor accumulated inside the board. This alleviates the defects of traditional coatings in terms of waterproofing and breathability imbalance. Combined with photothermal response characteristics, it can repair minor defects in the coating and help improve the long-term protective stability of the coating.

[0031] (2) The carbon nanotubes in the porous gradient composite modified filler prepared in this invention are prone to forming weak conductive pathways, posing a certain risk of interfacial micro-electrochemical corrosion under salt spray and acid rain environments. Furthermore, the filler's relatively high rigidity easily weakens the flexibility of the paint film, making it susceptible to micro-cracks under thermal cycling conditions. This invention modifies sodium lignosulfonate in two steps: first, hydrophobic segments are introduced through stearoyl chloride grafting; then, a silane coupling agent is used for surface modification to improve interfacial compatibility, resulting in modified sodium lignosulfonate. This modified material can block the conductive pathways of carbon nanotubes on the surface of the composite filler, reducing the risk of interfacial corrosion. Its flexible surface segments can improve the problem of weak paint film rigidity, enhance low-temperature deformation adaptability, and synergistically construct a hydrophobic barrier to reduce water vapor erosion. The resulting waterproof paint exhibits good overall performance, possessing certain wear resistance, weather resistance, waterproof and breathable properties, anti-aging properties, and micro-defect self-repair capabilities, making it well-suited for the long-term outdoor use requirements of exterior wall insulation panels. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below through embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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.

[0033] Unless otherwise stated, all raw materials and reagents used in this invention are commercially available or can be prepared by known methods.

[0034] Preparation Example 1 The preparation method of the composite modified filler includes the following steps: 1.0 parts by weight of zinc nitrate hexahydrate, 4.8 parts by weight of 2-methylimidazole and 0.06 parts by weight of multi-walled carbon nanotubes were dispersed in 100 parts by weight of mixed solvent (V anhydrous ethanol:V deionized water = 1:1). The pH was adjusted to 7.8 with sodium hydroxide solution. After ultrasonic dispersion at 200 W for 15 min at 24 °C, the mixture was stirred at 600 r / min for 12 h. After the reaction was completed, the precipitate was collected by centrifugation at 8000 r / min for 10 min. The precipitate was washed three times alternately with anhydrous ethanol and deionized water and dried under vacuum at 75 °C for 10 h to obtain a composite organic framework. 1.5 parts by weight of octadecylphosphonic acid were dispersed in 30 parts by weight of tetrahydrofuran and stirred at 200 r / min for 10 min. 0.3 parts by weight of a composite organic framework were added, and the mixture was heated to 45 °C and stirred at 300 r / min for 12 h. After the reaction was completed, the mixture was cooled to 26 °C, centrifuged at 8000 r / min for 10 min to collect the precipitate, washed three times with anhydrous methanol, and then dried under vacuum at 60 °C for 12 h to obtain a hydrophobic intermediate. 1.0 part by weight of the hydrophobic intermediate was dispersed in 50 parts by weight of anhydrous ethanol. After ultrasonic dispersion at 200W for 20 min, 0.08 parts by weight of dopamine hydrochloride was added, and the pH was adjusted to 8.0 with 25wt% ammonia. The temperature was raised to 30℃, and the reaction was stirred at 400 r / min for 10 h. After the reaction was completed, the temperature was cooled to 26℃, and the precipitate was collected by centrifugation at 9000 r / min for 10 min. The precipitate was washed three times alternately with anhydrous ethanol and deionized water, and then dried under vacuum at 60℃ for 12 h to obtain the composite intermediate. 0.8 parts by weight of terephthalic acid were dispersed in 40 parts by weight of N,N-dimethylformamide and stirred at 350 r / min for 10 min. 0.35 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added and stirred at 25 °C for 1.5 h to activate the mixture. Then, 0.15 parts by weight of N-hydroxysuccinimide and 1.0 parts by weight of 2-aminobenzamide were added. Under a nitrogen atmosphere, the mixture was heated to 50 °C and stirred at 300 r / min for 4 h. Then, 8 parts by weight of the composite intermediate were added and the mixture was stirred for another 5 h. After the reaction was completed, the mixture was cooled to 26 °C and centrifuged at 8000 r / min for 10 min to collect the solid. The solid was washed three times each with N,N-dimethylformamide, anhydrous ethanol, and deionized water, and then dried under vacuum at 55 °C for 12 h to obtain the composite modified filler.

[0035] Preparation Example 2 The preparation method of the composite modified filler includes the following steps: 1.0 parts by weight of zinc nitrate hexahydrate, 4.9 parts by weight of 2-methylimidazole and 0.08 parts by weight of multi-walled carbon nanotubes were dispersed in 100 parts by weight of mixed solvent (V anhydrous ethanol:V deionized water = 1:1). The pH was adjusted to 8.0 with sodium hydroxide solution. After ultrasonic dispersion at 220 W for 18 min at 25 °C, the mixture was stirred at 650 r / min for 12.5 h. After the reaction was completed, the precipitate was collected by centrifugation at 8000 r / min for 10 min. The precipitate was washed three times alternately with anhydrous ethanol and deionized water and dried under vacuum at 75 °C for 10 h to obtain a composite organic framework. 1.8 parts by weight of octadecylphosphonic acid were dispersed in 30 parts by weight of tetrahydrofuran and stirred at 200 r / min for 10 min. 0.35 parts by weight of a composite organic framework were added, and the mixture was heated to 48 °C and stirred at 350 r / min for 13 h. After the reaction was completed, the mixture was cooled to 26 °C, centrifuged at 8000 r / min for 10 min to collect the precipitate, washed three times with anhydrous methanol, and dried under vacuum at 60 °C for 12 h to obtain a hydrophobic intermediate. 1.05 parts by weight of the hydrophobic intermediate was dispersed in 50 parts by weight of anhydrous ethanol. After ultrasonic dispersion at 220 W for 22 min, 0.10 parts by weight of dopamine hydrochloride was added, and the pH was adjusted to 8.2 with 25 wt% ammonia. The temperature was raised to 32 °C, and the reaction was stirred at 450 r / min for 11 h. After the reaction was completed, the temperature was cooled to 26 °C, and the precipitate was collected by centrifugation at 9000 r / min for 10 min. The precipitate was washed three times alternately with anhydrous ethanol and deionized water, and then dried under vacuum at 60 °C for 12 h to obtain the composite intermediate. 0.82 parts by weight of terephthalic acid were dispersed in 40 parts by weight of N,N-dimethylformamide and stirred at 350 r / min for 10 min. 0.40 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added and stirred at 26 °C for 1.8 h to activate the mixture. Then, 0.18 parts by weight of N-hydroxysuccinimide and 1.2 parts by weight of 2-aminobenzamide were added. Under a nitrogen atmosphere, the mixture was heated to 55 °C and stirred at 350 r / min for 4.5 h. Then, 8.5 parts by weight of the composite intermediate were added and the mixture was stirred for another 5.5 h. After the reaction was completed, the mixture was cooled to 26 °C and centrifuged at 8000 r / min for 10 min to collect the solid. The solid was washed three times each with N,N-dimethylformamide, anhydrous ethanol, and deionized water, and then vacuum dried at 55 °C for 12 h to obtain the composite modified filler.

[0036] Preparation Example 3 The preparation method of the composite modified filler includes the following steps: 1.0 parts by weight of zinc nitrate hexahydrate, 5.0 parts by weight of 2-methylimidazole and 0.09 parts by weight of multi-walled carbon nanotubes were dispersed in 100 parts by weight of mixed solvent (V anhydrous ethanol:V deionized water = 1:1). The pH was adjusted to 8.2 with sodium hydroxide solution. After ultrasonic dispersion at 250 W for 20 min at 25 °C, the mixture was stirred at 700 r / min for 13 h. After the reaction was completed, the precipitate was collected by centrifugation at 8000 r / min for 10 min. The precipitate was washed three times alternately with anhydrous ethanol and deionized water and dried under vacuum at 75 °C for 10 h to obtain a composite organic framework. 2.0 parts by weight of octadecylphosphonic acid were dispersed in 30 parts by weight of tetrahydrofuran and stirred at 200 r / min for 10 min. 0.4 parts by weight of a composite organic framework were added, and the mixture was heated to 50 °C and stirred at 400 r / min for 14 h. After the reaction was completed, the mixture was cooled to 26 °C, centrifuged at 8000 r / min for 10 min to collect the precipitate, washed three times with anhydrous methanol, and then dried under vacuum at 60 °C for 12 h to obtain a hydrophobic intermediate. 1.1 parts by weight of the hydrophobic intermediate were dispersed in 50 parts by weight of anhydrous ethanol. After ultrasonic dispersion at 250W for 25 min, 0.12 parts by weight of dopamine hydrochloride were added, and the pH was adjusted to 8.4 with 25wt% ammonia. The temperature was raised to 34℃, and the reaction was stirred at 500 r / min for 12 h. After the reaction was completed, the temperature was cooled to 26℃, and the precipitate was collected by centrifugation at 9000 r / min for 10 min. The precipitate was washed three times alternately with anhydrous ethanol and deionized water, and then dried under vacuum at 60℃ for 12 h to obtain the composite intermediate. 0.85 parts by weight of terephthalic acid were dispersed in 40 parts by weight of N,N-dimethylformamide and stirred at 350 r / min for 10 min. 0.45 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added and stirred at 27 °C for 2.0 h to activate the mixture. Then, 0.20 parts by weight of N-hydroxysuccinimide and 1.3 parts by weight of 2-aminobenzamide were added. Under a nitrogen atmosphere, the mixture was heated to 60 °C and stirred at 350 r / min for 4.5 h. Then, 9.0 parts by weight of the composite intermediate were added and the reaction was continued for 6 h. After the reaction was completed, the mixture was cooled to 26 °C and centrifuged at 8000 r / min for 10 min to collect the solid. The solid was washed three times each with N,N-dimethylformamide, anhydrous ethanol, and deionized water, and then dried under vacuum at 55 °C for 12 h to obtain the composite modified filler.

[0037] Preparation Example 4 The preparation method of the composite modified filler includes the following steps: 1.0 parts by weight of zinc nitrate hexahydrate, 5.1 parts by weight of 2-methylimidazole and 0.10 parts by weight of multi-walled carbon nanotubes were dispersed in 100 parts by weight of mixed solvent (V anhydrous ethanol:V deionized water = 1:1). The pH was adjusted to 8.3 with sodium hydroxide solution. After ultrasonic dispersion at 280 W for 22 min at 26 °C, the mixture was stirred at 750 r / min for 13.5 h. After the reaction was completed, the precipitate was collected by centrifugation at 8000 r / min for 10 min. The precipitate was washed three times alternately with anhydrous ethanol and deionized water and dried under vacuum at 75 °C for 10 h to obtain a composite organic framework. 2.2 parts by weight of octadecylphosphonic acid were dispersed in 30 parts by weight of tetrahydrofuran and stirred at 200 r / min for 10 min. 0.45 parts by weight of a composite organic framework were added, and the mixture was heated to 52 °C and stirred at 450 r / min for 15 h. After the reaction was completed, the mixture was cooled to 26 °C, centrifuged at 8000 r / min for 10 min to collect the precipitate, washed three times with anhydrous methanol, and then dried under vacuum at 60 °C for 12 h to obtain a hydrophobic intermediate. 1.15 parts by weight of the hydrophobic intermediate were dispersed in 50 parts by weight of anhydrous ethanol. After ultrasonic dispersion at 280 W for 28 min, 0.14 parts by weight of dopamine hydrochloride were added, and the pH was adjusted to 8.6 with 25 wt% ammonia. The temperature was raised to 36 °C, and the reaction was stirred at 550 r / min for 13 h. After the reaction was completed, the temperature was cooled to 26 °C, and the precipitate was collected by centrifugation at 9000 r / min for 10 min. The precipitate was washed three times alternately with anhydrous ethanol and deionized water, and then vacuum dried at 60 °C for 12 h to obtain the composite intermediate. 0.88 parts by weight of terephthalic acid were dispersed in 40 parts by weight of N,N-dimethylformamide and stirred at 350 r / min for 10 min. 0.50 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added and stirred at 28 °C for 2.2 h for activation. Then, 0.22 parts by weight of N-hydroxysuccinimide and 1.5 parts by weight of 2-aminobenzamide were added. Under a nitrogen atmosphere, the mixture was heated to 65 °C and stirred at 400 r / min for 5 h. Then, 9.5 parts by weight of the composite intermediate were added and the reaction was continued for 6.5 h. After the reaction was completed, the mixture was cooled to 26 °C and centrifuged at 8000 r / min for 10 min to collect the solid. The solid was washed three times each with N,N-dimethylformamide, anhydrous ethanol, and deionized water, and then dried under vacuum at 55 °C for 12 h to obtain the composite modified filler.

[0038] Preparation Example 5 The preparation method of the composite modified filler includes the following steps: 1.0 parts by weight of zinc nitrate hexahydrate, 5.2 parts by weight of 2-methylimidazole and 0.12 parts by weight of multi-walled carbon nanotubes were dispersed in 100 parts by weight of mixed solvent (V anhydrous ethanol:V deionized water = 1:1). The pH was adjusted to 8.5 with sodium hydroxide solution. After ultrasonic dispersion at 26℃ and 300W for 25 min, the mixture was stirred at 800 r / min for 14 h. After the reaction was completed, the precipitate was collected by centrifugation at 8000 r / min for 10 min. The precipitate was washed three times alternately with anhydrous ethanol and deionized water and dried under vacuum at 75℃ for 10 h to obtain a composite organic framework. 2.5 parts by weight of octadecylphosphonic acid were dispersed in 30 parts by weight of tetrahydrofuran and stirred at 200 r / min for 10 min. 0.5 parts by weight of a composite organic framework were added, and the mixture was heated to 55 °C and stirred at 500 r / min for 16 h. After the reaction was completed, the mixture was cooled to 26 °C, centrifuged at 8000 r / min for 10 min to collect the precipitate, washed three times with anhydrous methanol, and then dried under vacuum at 60 °C for 12 h to obtain a hydrophobic intermediate. 1.2 parts by weight of the hydrophobic intermediate were dispersed in 50 parts by weight of anhydrous ethanol. After ultrasonic dispersion at 300W for 30 min, 0.15 parts by weight of dopamine hydrochloride were added, and the pH was adjusted to 8.8 with 25wt% ammonia. The temperature was raised to 38℃, and the reaction was stirred at 600 r / min for 14 h. After the reaction was completed, the temperature was cooled to 26℃, and the precipitate was collected by centrifugation at 9000 r / min for 10 min. The precipitate was washed three times alternately with anhydrous ethanol and deionized water, and then dried under vacuum at 60℃ for 12 h to obtain the composite intermediate. 0.9 parts by weight of terephthalic acid were dispersed in 40 parts by weight of N,N-dimethylformamide and stirred at 350 r / min for 10 min. 0.55 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added and stirred at 30 °C for 2.5 h to activate the mixture. Then, 0.25 parts by weight of N-hydroxysuccinimide and 1.6 parts by weight of 2-aminobenzamide were added. Under a nitrogen atmosphere, the mixture was heated to 70 °C and stirred at 400 r / min for 5 h. Then, 10 parts by weight of the composite intermediate were added and the mixture was stirred for another 7 h. After the reaction was completed, the mixture was cooled to 26 °C and centrifuged at 8000 r / min for 10 min to collect the solid. The solid was washed three times each with N,N-dimethylformamide, anhydrous ethanol, and deionized water, and then dried under vacuum at 55 °C for 12 h to obtain the composite modified filler.

[0039] Preparation Example 6 The preparation method of modified sodium lignosulfonate includes the following steps: 1.0 part by weight of sodium lignosulfonate was dispersed in 50 parts by weight of N,N-dimethylformamide and stirred at 300 r / min for 15 min. 0.8 parts by weight of triethylamine was added and stirring was continued for 10 min. 0.4 parts by weight of stearyl chloride was added under a nitrogen atmosphere. The mixture was heated to 50 °C and stirred at 400 r / min for 4 h. After the reaction was completed, the reaction solution was slowly poured into 10 times the volume of deionized water to precipitate. The precipitate was collected by centrifugation at 8000 r / min for 10 min, washed three times with anhydrous ethanol, and dried under vacuum at 60 °C for 24 h to obtain the first intermediate. 0.8 parts by weight of the first intermediate were dispersed in 30 parts by weight of anhydrous ethanol. After stirring at 250 r / min for 10 min, 0.18 parts by weight of silane coupling agent KH-570 were added, the pH was adjusted to 4.0, the temperature was raised to 55℃, and the reaction was stirred at 350 r / min for 6 h. After the reaction was completed, the temperature was cooled to 26℃, the precipitate was collected by centrifugation at 8000 r / min for 10 min, washed three times with anhydrous ethanol, and dried under vacuum at 60℃ for 24 h to obtain modified sodium lignosulfonate.

[0040] Preparation Example 7 The preparation method of modified sodium lignosulfonate includes the following steps: 1.0 part by weight of sodium lignosulfonate was dispersed in 50 parts by weight of N,N-dimethylformamide and stirred at 300 r / min for 15 min. 0.9 parts by weight of triethylamine was added and stirring was continued for 10 min. 0.45 parts by weight of stearyl chloride was added under a nitrogen atmosphere. The mixture was heated to 52 °C and stirred at 420 r / min for 4 h. After the reaction was completed, the reaction solution was slowly poured into 10 times the volume of deionized water to precipitate. The precipitate was collected by centrifugation at 8000 r / min for 10 min, washed three times with anhydrous ethanol, and dried under vacuum at 60 °C for 24 h to obtain the first intermediate. 0.9 parts by weight of the first intermediate were dispersed in 30 parts by weight of anhydrous ethanol. After stirring at 250 r / min for 10 min, 0.20 parts by weight of silane coupling agent KH-570 were added, the pH was adjusted to 4.2, the temperature was raised to 58℃, and the reaction was stirred at 350 r / min for 6.5 h. After the reaction was completed, the temperature was cooled to 26℃, the precipitate was collected by centrifugation at 8000 r / min for 10 min, washed three times with anhydrous ethanol, and dried under vacuum at 60℃ for 24 h to obtain modified sodium lignin sulfonate.

[0041] Preparation Example 8 The preparation method of modified sodium lignosulfonate includes the following steps: 1.0 part by weight of sodium lignosulfonate was dispersed in 50 parts by weight of N,N-dimethylformamide and stirred at 300 r / min for 15 min. 1.0 part by weight of triethylamine was added and stirring was continued for 10 min. 0.5 part by weight of stearyl chloride was added under a nitrogen atmosphere. The temperature was raised to 55 °C and stirred at 450 r / min for 4.5 h. After the reaction was completed, the reaction solution was slowly poured into 10 times the volume of deionized water to precipitate. The precipitate was collected by centrifugation at 8000 r / min for 10 min, washed three times with anhydrous ethanol, and dried under vacuum at 60 °C for 24 h to obtain the first intermediate. 1.0 part by weight of the first intermediate was dispersed in 30 parts by weight of anhydrous ethanol. After stirring at 250 r / min for 10 min, 0.22 parts by weight of silane coupling agent KH-570 was added, the pH was adjusted to 4.2, the temperature was raised to 60℃, and the reaction was stirred at 350 r / min for 7 h. After the reaction was completed, the temperature was cooled to 26℃, the precipitate was collected by centrifugation at 8000 r / min for 10 min, washed 3 times with anhydrous ethanol, and dried under vacuum at 60℃ for 24 h to obtain modified sodium lignosulfonate.

[0042] Preparation Example 9 The preparation method of modified sodium lignosulfonate includes the following steps: 1.0 part by weight of sodium lignosulfonate was dispersed in 50 parts by weight of N,N-dimethylformamide and stirred at 300 r / min for 15 min. 1.1 parts by weight of triethylamine was added and stirring was continued for 10 min. 0.55 parts by weight of stearyl chloride was added under a nitrogen atmosphere. The temperature was raised to 58 °C and stirred at 480 r / min for 4.5 h. After the reaction was completed, the reaction solution was slowly poured into 10 times the volume of deionized water to precipitate. The precipitate was collected by centrifugation at 8000 r / min for 10 min, washed three times with anhydrous ethanol, and dried under vacuum at 60 °C for 24 h to obtain the first intermediate. 1.1 parts by weight of the first intermediate were dispersed in 30 parts by weight of anhydrous ethanol. After stirring at 250 r / min for 10 min, 0.25 parts by weight of silane coupling agent KH-570 were added, the pH was adjusted to 4.4, the temperature was raised to 62℃, and the reaction was stirred at 350 r / min for 7.5 h. After the reaction was completed, the temperature was cooled to 26℃, the precipitate was collected by centrifugation at 8000 r / min for 10 min, washed three times with anhydrous ethanol, and dried under vacuum at 60℃ for 24 h to obtain modified sodium lignosulfonate.

[0043] Preparation Example 10 The preparation method of modified sodium lignosulfonate includes the following steps: 1.0 part by weight of sodium lignosulfonate was dispersed in 50 parts by weight of N,N-dimethylformamide and stirred at 300 r / min for 15 min. 1.2 parts by weight of triethylamine was added and stirring was continued for 10 min. 0.6 parts by weight of stearyl chloride was added under a nitrogen atmosphere. The mixture was heated to 60 °C and stirred at 500 r / min for 5 h. After the reaction was completed, the reaction solution was slowly poured into 10 times the volume of deionized water to precipitate. The precipitate was collected by centrifugation at 8000 r / min for 10 min, washed three times with anhydrous ethanol, and dried under vacuum at 60 °C for 24 h to obtain the first intermediate. 1.2 parts by weight of the first intermediate were dispersed in 30 parts by weight of anhydrous ethanol. After stirring at 250 r / min for 10 min, 0.28 parts by weight of silane coupling agent KH-570 were added, the pH was adjusted to 4.5, the temperature was raised to 65℃, and the reaction was stirred at 350 r / min for 8 h. After the reaction was completed, the temperature was cooled to 26℃, the precipitate was collected by centrifugation at 8000 r / min for 10 min, washed 3 times with anhydrous ethanol, and dried under vacuum at 60℃ for 24 h to obtain modified sodium lignosulfonate.

[0044] Preparation Example 11 The preparation method of the composite modified filler includes the following steps: The composite organic framework in Preparation Example 5 was replaced with an equal weight of nano-silica (200 nm), and all other operations were the same as in Preparation Example 5.

[0045] Preparation Example 12 The preparation method of the composite modified filler includes the following steps: In Preparation Example 5, octadecylphosphonic acid was replaced with an equal weight of stearic acid, and all other operations were the same as in Preparation Example 5.

[0046] Preparation Example 13 The preparation method of the composite modified filler includes the following steps: In Preparation Example 5, 2-aminobenzimidazole was replaced with an equal mass of aminopentadecane, and all other operations were the same as in Preparation Example 5.

[0047] Preparation Example 14 The preparation method of the composite modified filler includes the following steps: Remove the multi-walled carbon nanotubes from Preparation Example 5, and keep the other operations the same as in Preparation Example 5.

[0048] Preparation Example 15 The preparation method of modified sodium lignosulfonate includes the following steps: The silane coupling agent modification step in Preparation Example 10 was removed, and only stearoyl chloride single-step modification was performed. Other operations were the same as in Preparation Example 10.

[0049] Example 1 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: 1.0 parts by weight of sodium dodecyl sulfate and 0.8 parts by weight of emulsifier DNS-86 were dispersed in 15 parts by weight of deionized water and stirred at 400 r / min for 10 min. 1.0 parts by weight of modified sodium lignosulfonate prepared in Preparation Example 6, 35 parts by weight of methyl methacrylate, 25 parts by weight of butyl acrylate, 2 parts by weight of methacrylic acid and 5 parts by weight of methyl vinyl dimethoxysilane were added and stirred for 30 min to obtain a pre-emulsion. 0.4 parts by weight of ammonium persulfate were added, and the mixture was heated to 85°C under a nitrogen atmosphere and stirred for 4 h. After the reaction was completed, the mixture was cooled to 26°C, the pH was adjusted to 7.0, and the solid content was adjusted to 45 wt% to obtain an acrylic emulsion. 100 parts by weight of acrylic emulsion and 15 parts by weight of deionized water were added to a mixing tank and stirred at 300 r / min for 10 min. Then, 7 parts by weight of the composite modified filler prepared in Preparation Example 1 were added and stirred and dispersed at 800 r / min for 25 min. Then, 0.3 parts by weight of Rohm and Haas leveling agent RM-2020 and 0.2 parts by weight of Evonik Surfynol DF-110D were added and stirred at 300 r / min for 15 min. After standing for 30 min, the mixture was filtered through a 100-mesh sieve to obtain a waterproof paint for use on exterior wall insulation boards.

[0050] Example 2 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: 1.1 parts by weight of sodium dodecyl sulfate and 0.9 parts by weight of emulsifier DNS-86 were dispersed in 18 parts by weight of deionized water and stirred at 400 r / min for 12 min. 1.2 parts by weight of modified sodium lignosulfonate prepared in Preparation Example 7, 36 parts by weight of methyl methacrylate, 26 parts by weight of butyl acrylate, 2 parts by weight of methacrylic acid and 6 parts by weight of methyl vinyl dimethoxysilane were added and stirred for 35 min to obtain a pre-emulsion. 0.4 parts by weight of ammonium persulfate were added, and the mixture was heated to 88°C under a nitrogen atmosphere and stirred for 4 h. After the reaction was completed, the mixture was cooled to 26°C, the pH was adjusted to 7.2, and the solid content was adjusted to 45 wt% to obtain an acrylic emulsion. 100 parts by weight of acrylic emulsion and 18 parts by weight of deionized water were added to a mixing tank and stirred at 300 r / min for 10 min. Then, 7.5 parts by weight of the composite modified filler prepared in Preparation Example 2 were added and stirred and dispersed at 850 r / min for 28 min. Then, 0.4 parts by weight of Rohm and Haas leveling agent RM-2020 and 0.3 parts by weight of Evonik Surfynol DF-110D were added and stirred at 300 r / min for 18 min. After standing for 32 min, the mixture was filtered through a 100-mesh sieve to obtain a waterproof paint for use on exterior wall insulation boards.

[0051] Example 3 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: 1.2 parts by weight of sodium dodecyl sulfate and 1.0 parts by weight of emulsifier DNS-86 were dispersed in 20 parts by weight of deionized water and stirred at 450 r / min for 12 min. 1.3 parts by weight of modified sodium lignosulfonate prepared in Preparation Example 8, 37 parts by weight of methyl methacrylate, 27 parts by weight of butyl acrylate, 2.5 parts by weight of methacrylic acid and 6 parts by weight of methyl vinyl dimethoxysilane were added and stirred for 40 min to obtain a pre-emulsion. 0.5 parts by weight of ammonium persulfate were added, and the mixture was heated to 90 °C under a nitrogen atmosphere and stirred for 4.5 h. After the reaction was completed, the mixture was cooled to 26 °C, the pH was adjusted to 7.5, and the solid content was adjusted to 45 wt% to obtain an acrylic emulsion. 100 parts by weight of acrylic emulsion and 20 parts by weight of deionized water were added to a mixing tank and stirred at 350 r / min for 10 min. Then, 8.0 parts by weight of the composite modified filler prepared in Preparation Example 3 were added and stirred and dispersed at 900 r / min for 30 min. Then, 0.4 parts by weight of Rohm and Haas leveling agent RM-2020 and 0.3 parts by weight of Evonik Surfynol DF-110D were added and stirred at 350 r / min for 20 min. After standing for 32 min, the mixture was filtered through a 100-mesh sieve to obtain a waterproof paint for use on exterior wall insulation boards.

[0052] Example 4 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: 1.3 parts by weight of sodium dodecyl sulfate and 1.1 parts by weight of emulsifier DNS-86 were dispersed in 22 parts by weight of deionized water and stirred at 450 r / min for 15 min. 1.4 parts by weight of modified sodium lignosulfonate prepared in Preparation Example 9, 38 parts by weight of methyl methacrylate, 28 parts by weight of butyl acrylate, 2.5 parts by weight of methacrylic acid and 7 parts by weight of methyl vinyl dimethoxysilane were added and stirred for 45 min to obtain a pre-emulsion. 0.5 parts by weight of ammonium persulfate were added, and the mixture was heated to 92 °C under a nitrogen atmosphere and stirred for 4.5 h. After the reaction was completed, the mixture was cooled to 26 °C, the pH was adjusted to 7.8, and the solid content was adjusted to 45 wt% to obtain an acrylic emulsion. 100 parts by weight of acrylic emulsion and 22 parts by weight of deionized water were added to a mixing tank and stirred at 350 r / min for 10 min. Then, 8.5 parts by weight of the composite modified filler prepared in Preparation Example 4 were added and stirred and dispersed at 950 r / min for 32 min. Then, 0.5 parts by weight of Rohm and Haas leveling agent RM-2020 and 0.4 parts by weight of Evonik Surfynol DF-110D were added and stirred at 350 r / min for 22 min. After standing for 35 min, the mixture was filtered through a 100-mesh sieve to obtain a waterproof paint for exterior wall insulation boards.

[0053] Example 5 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: 1.5 parts by weight of sodium dodecyl sulfate and 1.2 parts by weight of emulsifier DNS-86 were dispersed in 20 parts by weight of deionized water and stirred at 500 r / min for 15 min. 1.6 parts by weight of modified sodium lignosulfonate prepared in Preparation Example 10, 40 parts by weight of methyl methacrylate, 30 parts by weight of butyl acrylate, 3 parts by weight of methacrylic acid and 8 parts by weight of methyl vinyl dimethoxysilane were added and stirred for 50 min to obtain a pre-emulsion. 0.6 parts by weight of ammonium persulfate were added, and the mixture was heated to 95°C under a nitrogen atmosphere and stirred for 5 h. After the reaction was completed, the mixture was cooled to 26°C, the pH was adjusted to 8.0, and the solid content was adjusted to 45 wt% to obtain an acrylic emulsion. 100 parts by weight of acrylic emulsion and 25 parts by weight of deionized water were added to a mixing tank and stirred at 400 r / min for 10 min. Then, 9.0 parts by weight of the composite modified filler prepared in Preparation Example 5 were added and stirred and dispersed at 1000 r / min for 35 min. Then, 0.6 parts by weight of Rohm and Haas leveling agent RM-2020 and 0.5 parts by weight of Evonik Surfynol DF-110D were added and stirred at 400 r / min for 25 min. After standing for 35 min, the mixture was filtered through a 100-mesh sieve to obtain a waterproof paint for use on exterior wall insulation boards.

[0054] Comparative Example 1 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: The composite modified filler prepared in Example 5 was replaced with the composite modified filler prepared in Example 11, and other operations were kept the same as in Example 5.

[0055] Comparative Example 2 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: The composite modified filler prepared in Example 5 was replaced with the composite modified filler prepared in Example 12, and other operations were kept the same as in Example 5.

[0056] Comparative Example 3 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: The modified sodium lignin sulfonate prepared in Example 10 of Example 5 was replaced with an equal weight of unmodified sodium lignin sulfonate, and other operations were kept the same as in Example 5.

[0057] Comparative Example 4 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: The composite modified filler prepared in Example 5 was replaced with the composite modified filler prepared in Example 13, and other operations were kept the same as in Example 5.

[0058] Comparative Example 5 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: The composite modified filler prepared in Example 5 was replaced with the composite modified filler prepared in Example 14, and other operations were kept the same as in Example 5.

[0059] Comparative Example 6 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: The composite modified filler prepared in Example 5 was replaced with the composite modified filler prepared in Example 15, and other operations were kept the same as in Example 5.

[0060] Comparative Example 7 A method for preparing a waterproof paint for exterior wall insulation boards includes the following steps: Remove the modified sodium lignin sulfonate obtained in Preparation Example 10 of Example 5, and keep all other operations consistent with Example 5.

[0061] Performance testing Standard exterior wall cement mortar test panels (150mm×70mm×5mm) were selected as the coating substrate. The waterproof paints prepared in Examples 1-5 and Comparative Examples 1-7 were allowed to stand for 30 minutes to defoam, then slowly stirred with a glass rod for 2 minutes. The paints were then uniformly applied to the surface of the cement mortar test panels. The dry film thickness of all samples was uniformly controlled at (40±2) μm. After the test coating was completed, the test panels were allowed to stand for 30 minutes to dry. All surface-dried test panels were then placed in a constant temperature and humidity curing chamber, with a curing temperature of 25℃ and a relative humidity of 50%. After 7 days of continuous standard curing, the resulting samples were used for subsequent performance tests. Water contact angle test: The test was conducted using a fully automatic optical contact angle measuring instrument. The test environment was constant at 25℃ and relative humidity at 50%±5%. Before the test, the cured coating sample was kept at a constant temperature for 30 minutes. 5μL of standard deionized water was added to the flat surface of the coating using a micro-syringe. After the droplet stabilized for 10 seconds, the static contact angle value was read. Abrasion resistance test: The abrasion tester was used for the test. The test environment was 25℃ and normal pressure. The test load was fixed at 1000g. A CS-10 standard friction wheel was selected. After pre-grinding for 50 revolutions to remove the surface floating layer, the sample was subjected to formal friction for 500 revolutions. Before and after the test, the sample was placed in a 105℃ oven for 30 minutes to dry. After cooling to room temperature, the sample was weighed accurately, and the mass difference of the coating before and after wear was calculated. Water vapor transmission rate test: Refer to the test method in JG-T 309-2011 "Determination and classification of water vapor transmission rate of exterior wall coatings" and determine the water vapor transmission rate per unit area and per unit time of the coating by weighing method. UV aging residual contact angle test: The UV340 UV aging test chamber was used with a UV wavelength of 340nm, an aging environment temperature of 60℃, and a continuous UV irradiation time of 240h. After the aging test, the sample was taken out and placed in an environment of 25℃ and 50% humidity for 30min to recover. The residual contact angle was tested according to the water contact angle test standard. Self-healing performance test: Using a standard surgical knife, uniform scratches with a width of 20μm and a depth penetrating the coating were prepared on the surface of the cured and smooth coating. The scratched samples were then horizontally placed and kept at a constant temperature for 24 hours. The curing environment was 25℃ and 50%±5% relative humidity. The scratch width before and after repair was observed, and the scratch healing rate was calculated (healing rate = (initial scratch width - residual scratch width) / initial scratch width × 100%). The test results are shown in Table 1.

[0062] Table 1. Performance Test Results Example 1 143.2 8.6 325 128.5 72.3 Example 2 144.5 8.2 332 130.2 76.5 Example 3 145.8 7.9 338 132.6 80.2 Example 4 146.5 7.6 342 134.1 85.7 Example 5 147.2 7.3 346 136.8 91.4 Comparative Example 1 125.6 14.2 221 96.3 42.6 Comparative Example 2 133.8 10.5 295 112.5 58.3 Comparative Example 3 131.2 9.7 278 109.2 51.7 Comparative Example 4 139.5 11.2 315 118.6 65.2 Comparative Example 5 141.6 9.1 326 121.3 70.5 Comparative Example 6 137.4 8.8 306 115.9 62.8 Comparative Example 7 140.2 8.5 312 124.7 68.1 The test results in Table 1 show that the waterproof paint for exterior wall insulation boards prepared in Examples 1-5 of this invention exhibits good comprehensive application performance in terms of hydrophobicity, abrasion resistance, water vapor permeability, and self-healing properties, and can be adapted to the complex outdoor use conditions of exterior wall insulation boards.

[0063] The decrease in Comparative Example 1 may be due to the loss of ZIF-8's unique hierarchical porous structure after the replacement of the composite modified filler with nano-silica. Inert inorganic silica has poor compatibility with the organic coating matrix, failing to construct a complete and stable hydrophobic interface, resulting in decreased hydrophobic performance. Simultaneously, the lack of stress reinforcement from the organic framework leads to poorer coating structural stability and reduced wear resistance. Disordered inorganic particles disrupt the coating's regular microporous structure, blocking water vapor transport channels and weakening water vapor permeability. Furthermore, these inorganic particles lack dynamic response characteristics and cannot construct a self-healing cross-linking system, causing a significant reduction in the coating's self-healing performance.

[0064] The decrease in hydrophobicity in Comparative Example 2 may be due to the poor hydrophobic grafting effect and insufficient bonding stability of the filler surface after stearic acid replaced octadecylphosphonic acid for hydrophobic modification, resulting in the inability to form a long-lasting hydrophobic surface layer and a decline in the coating's hydrophobic performance. The loose bonding between the modified filler and the resin matrix leads to microscopic defects within the coating, reducing structural density and wear resistance. Simultaneously, the unstable modified structure disrupts the micropore arrangement of the coating, hindering water vapor diffusion and reducing water vapor permeability. Furthermore, the stearic acid-modified system cannot form a dynamic reversible interface, making it difficult for the coating to complete molecular recombination and scratch closure after damage, significantly reducing its self-healing properties.

[0065] The decrease in Comparative Example 3 may be due to the fact that after virgin sodium lignin sulfonate replaces modified sodium lignin sulfonate, the numerous hydrophilic groups on its surface disrupt the hydrophobic interface of the coating, leading to a decline in hydrophobic properties. Virgin sodium lignin sulfonate lacks cross-linking reinforcement and cannot improve the structural strength of the coating, resulting in weak resistance to frictional wear. Furthermore, it easily aggregates in the system, creating structural defects, disrupting the distribution of micropores in the coating, hindering water vapor conduction, and reducing water vapor permeability. Moreover, virgin sodium lignin sulfonate lacks dynamic cross-linking properties and cannot provide a self-healing basis for the coating, leading to a significant decrease in the coating's self-healing ability.

[0066] The decrease in Comparative Example 4 may be due to the loss of multiple active grafting sites and conjugated cyclic structure after aminopentadecane replaced 2-aminobenzimidazole. The linear aminopentadecane has low crosslinking activity, failing to construct a stable and dense crosslinking network, resulting in a loose coating structure with numerous interface defects and a significant decrease in hydrophobicity. The lack of a crosslinking network leads to insufficient mechanical strength and poor wear resistance. The loose internal structure cannot form regular, breathable micropores, increasing water vapor transport resistance and reducing water vapor permeability. Furthermore, the system lacks a dynamic and reversible molecular interaction mechanism, preventing structural reconstruction after scratches and significantly diminishing self-healing performance.

[0067] The decrease in Comparative Example 5 may be due to the removal of multi-walled carbon nanotubes, which resulted in the loss of a one-dimensional nano-framework support and structural control components. The coating lacks a continuous mechanical reinforcement structure, leading to decreased mechanical stability and reduced wear resistance. Simultaneously, the filler's dispersibility deteriorates, causing it to agglomerate and disrupting the integrity and uniformity of the hydrophobic interface, thus reducing hydrophobic properties. The interconnected microporous channels constructed by carbon nanotubes are also lost, resulting in poor pore connectivity and weakened water vapor permeability. Furthermore, without the stress relief and interfacial conduction effects of carbon nanotubes, molecular recombination at scratches is hindered, making it difficult for microscopic damage to repair itself, thus reducing self-healing performance.

[0068] The decrease in Comparative Example 6 may be due to the fact that sodium lignosulfonate only underwent single-step stearoyl chloride modification, lacking a silane coupling agent bridging structure. This significantly reduced the interfacial compatibility between the modified product and the coating matrix, making it prone to generating microscopic gaps and defects within the coating, disrupting the continuity of the hydrophobic interface, and resulting in poorer hydrophobic performance. Insufficient interfacial bonding reduces the overall structural stability of the coating, consequently decreasing its wear resistance and damage resistance. Internal defects disrupt and block the permeable micropores, damaging water vapor transport pathways and weakening water vapor permeability. Simultaneously, the system cannot form a dynamic reversible cross-linked interface, making it difficult for the coating to achieve interfacial reconstruction and scratch closure after damage, significantly reducing its self-healing performance.

[0069] The decrease in Comparative Example 7 may be due to the complete removal of modified sodium lignosulfonate, resulting in the loss of core components for interface regulation and structural optimization. The uniformity of functional filler dispersion significantly decreased, leading to agglomeration and accumulation, which undermined the density of the coating's hydrophobic structure and reduced hydrophobic properties. Structural defects caused by filler agglomeration weakened the coating's mechanical stability, making it more susceptible to wear and detachment, and reducing its abrasion resistance. Simultaneously, the disordered and poorly connected microporous structure of the coating hindered water vapor conduction, resulting in decreased water vapor permeability. Furthermore, the system lost its dynamic self-healing active components, failing to establish a self-repairing response mechanism, making it difficult for the coating's micro-scratches to repair themselves, and significantly reducing its self-healing performance.

[0070] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for preparing a waterproof paint for exterior wall insulation boards, characterized in that, The preparation method includes the following steps: Sodium dodecyl sulfate, emulsifier, modified sodium lignosulfonate, methyl methacrylate, butyl acrylate, methacrylic acid and methyl vinyl dimethoxysilane are mixed and stirred to obtain a pre-emulsion, and then ammonium persulfate is added and stirred to obtain an acrylic emulsion. The waterproof paint is prepared by mixing and stirring acrylic emulsion, deionized water, composite modified filler, leveling agent and defoamer.

2. The method for preparing a waterproof paint for exterior wall insulation boards as described in claim 1, characterized in that, The preparation method of the modified sodium lignin sulfonate includes the following steps: Sodium lignosulfonate, triethylamine, and stearoyl chloride were mixed and stirred to react, yielding the first intermediate. Modified sodium lignin sulfonate was prepared by mixing and stirring the first intermediate with silane coupling agent KH-570.

3. The method for preparing a waterproof paint for exterior wall insulation boards as described in claim 2, characterized in that, The weight ratio of sodium lignosulfonate, triethylamine, and stearoyl chloride is 1.0:0.8~1.2:0.4~0.6; the conditions for the mixing and stirring reaction of sodium lignosulfonate, triethylamine, and stearoyl chloride include a reaction temperature of 50~60℃, a reaction speed of 400~500 r / min, and a reaction time of 4~5 h.

4. The method for preparing a waterproof paint for exterior wall insulation boards as described in claim 2, characterized in that, The weight ratio of the first intermediate to the silane coupling agent KH-570 is 0.8~1.2:0.18~0.28; the conditions for the mixing and stirring reaction of the first intermediate and the silane coupling agent KH-570 include a reaction temperature of 55~65℃, a reaction pH of 4.0~4.5, and a reaction time of 6~8h.

5. The method for preparing a waterproof paint for exterior wall insulation boards as described in claim 2, characterized in that, The mixing and stirring conditions for sodium dodecyl sulfate, emulsifier, modified sodium lignosulfonate, methyl methacrylate, butyl acrylate, methacrylic acid, and methyl vinyldimethoxysilane include a mixing speed of 400-500 r / min and a mixing time of 30-50 min; the weight ratio of sodium dodecyl sulfate, emulsifier, modified sodium lignosulfonate, methyl methacrylate, butyl acrylate, methacrylic acid, methyl vinyldimethoxysilane, and ammonium persulfate is 1.0-1.5:0.8-1.2:1.0-1.6:35-40:25-30:2-3:5-8:0.4-0.6; the reaction conditions for adding ammonium persulfate and stirring include a reaction temperature of 85-95℃ and a reaction time of 4-5 h.

6. The method for preparing a waterproof paint for exterior wall insulation boards as described in claim 1, characterized in that, The preparation method of the composite modified filler includes the following steps: A composite organic framework was obtained by mixing and stirring zinc nitrate hexahydrate, 2-methylimidazole and multi-walled carbon nanotubes. A hydrophobic intermediate was obtained by mixing and stirring octadecyl phosphoric acid and a complex organic framework. A complex intermediate was obtained by mixing and stirring a hydrophobic intermediate with dopamine hydrochloride. A composite modified filler was prepared by mixing and stirring terephthalic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide, 2-aminobenzylimidazole and a composite intermediate.

7. The method for preparing a waterproof paint for exterior wall insulation boards as described in claim 6, characterized in that, The weight ratio of zinc nitrate hexahydrate, 2-methylimidazole, and multi-walled carbon nanotubes is 1.0:4.8~5.2:0.06~0.12; the reaction conditions for mixing and stirring zinc nitrate hexahydrate, 2-methylimidazole, and multi-walled carbon nanotubes include a reaction pH of 7.8~8.5, a reaction temperature of 130~140℃, and a reaction time of 12~14h; the weight ratio of octadecyl phosphoric acid and the composite organic framework is 1.5~2.5:0.3~0.5; the reaction conditions for mixing and stirring octadecyl phosphoric acid and the composite organic framework include a reaction temperature of 45~55℃ and a reaction time of 12~16h; the weight ratio of the hydrophobic intermediate and dopamine hydrochloride is 1.0~1.2:0.08~0.15; the reaction conditions for mixing and stirring the hydrophobic intermediate and dopamine hydrochloride include a reaction pH of 8.0~8.8, a reaction temperature of 30~38℃, and a reaction time of 10~14h.

8. The method for preparing a waterproof paint for exterior wall insulation boards as described in claim 6, characterized in that, The weight ratio of terephthalic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide, 2-aminobenzimidazole, and the composite intermediate is 0.8~0.8:0.35~0.55:0.15~0.25:1.0~1.6:8~10; the reaction conditions for mixing and stirring the terephthalic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide, 2-aminobenzimidazole, and the composite intermediate include a reaction temperature of 50~70℃ and a reaction time of 5~7h.

9. The method for preparing a waterproof paint for exterior wall insulation boards as described in claim 1, characterized in that, The acrylic emulsion has a solid content of 45 wt%; the leveling agent is Rohm and Haas leveling agent RM-2020; the defoamer is Evonik Surfynol DF-110D; the weight ratio of the acrylic emulsion, deionized water, composite modified filler, leveling agent and defoamer is 100:15~25:7~9:0.3~0.6:0.2~0.

5.

10. A waterproof paint for exterior wall insulation boards, characterized in that, It is prepared by the method for preparing a waterproof paint for exterior wall insulation board as described in any one of claims 1 to 9.