A single-component bituminous polyurethane waterproof coating and its preparation method

Abstract

This invention relates to the field of coating technology, and more particularly to a one-component bituminous polyurethane waterproof coating and its preparation method. The one-component bituminous polyurethane waterproof coating provided by this invention comprises the following raw materials: 30-70 parts by weight of diisocyanate, 100-300 parts by weight of polyether polyol, 50-100 parts by weight of modified polyol, 100-300 parts by weight of reactive plasticizer, 15-50 parts by weight of latent curing agent, 0.1-0.5 parts by weight of first catalyst, 100-550 parts by weight of pigments and fillers, and 30-80 parts by weight of first solvent. The one-component bituminous polyurethane waterproof coating provided by this invention exhibits strong adhesion to bituminous roofing membranes and maintains a firm composite state under acid, alkali, and heat conditions, while also possessing excellent mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a single-component bituminous polyurethane waterproof coating and its preparation method. Background Technology

[0002] Polyurethane waterproof coating is a reaction-curing coating made by addition polymerization of raw materials such as isocyanate and polyether. Due to the high strength, high elongation and good water resistance of the coating film it forms, polyurethane waterproof coating has been widely used in waterproofing projects.

[0003] In recent years, with the industry's increasing demands for waterproofing reliability, many waterproofing projects (especially in the building and road and bridge sectors) have begun to adopt composite waterproofing systems consisting of coatings and membrane rolls, i.e., setting at least two waterproofing layers to achieve a longer-lasting and more reliable waterproofing effect. In this composite waterproofing process, the combination of polyurethane waterproof coatings and asphalt waterproof membrane rolls is a common solution.

[0004] However, existing technologies face a key technical challenge when applying this composite waterproofing solution. Conventional polyurethane waterproofing coatings are highly polar materials, while bitumen waterproofing membranes are non-polar or low-polar materials. Due to this significant difference in material polarity, the compatibility between the polyurethane coating layer and the bitumen membrane layer is poor, resulting in unsatisfactory adhesion. This poor adhesion may not be noticeable initially, but with long-term use, especially after exposure to high temperatures, interlayer delamination is highly likely to occur, leading to premature failure of the composite waterproofing system and severely impacting the reliability and durability of the overall waterproofing project.

[0005] Furthermore, existing polyurethane waterproof coatings typically contain plasticizers to adjust flexibility. However, these conventional plasticizers are prone to migration under high-temperature conditions, meaning they seep out from the cured coating. This migration further deteriorates the adhesion between the coating and the membrane, increasing the risk of peeling between the two waterproof layers.

[0006] Therefore, how to effectively improve the adhesion between polyurethane waterproof coatings and asphalt-based membranes, and ensure that they can maintain a strong composite state under conditions such as heat, is an urgent problem to be solved in the current waterproofing technology field. Summary of the Invention

[0007] This invention provides a single-component asphalt-friendly polyurethane waterproof coating and its preparation method, which solves the problems of poor adhesion and easy interlayer delamination caused by the incompatibility of polarity between existing polyurethane waterproof coatings and asphalt rolls.

[0008] According to a first aspect of the present invention, the present invention provides a one-component bituminous polyurethane waterproof coating, comprising the following raw materials: 30-70 parts by weight of diisocyanate, 100-300 parts by weight of polyether polyol, 50-100 parts by weight of modified polyol, 100-300 parts by weight of reactive plasticizer, 15-50 parts by weight of latent curing agent, 0.1-0.5 parts by weight of first catalyst, 100-550 parts by weight of pigments and fillers, and 30-80 parts by weight of first solvent.

[0009] The single-component bituminous polyurethane waterproof coating provided by this invention introduces modified polyols and reactive plasticizers into a specific formulation system. The synergistic effect between the components not only gives the prepared waterproof coating excellent physical properties (such as high tensile strength and high elongation at break), but also allows it to form a strong whole when combined with asphalt rolls, solving the fundamental problem of poor adhesion between traditional polyurethane coatings and asphalt substrates. Specifically, the modified polyols effectively wet and anchor on the non-polar asphalt surface, establishing a strong affinity and adhesion foundation between the coating and asphalt at a chemical level. The hydrocarbon backbone in the modified polyols is relatively flexible with low chain segment movement resistance, significantly improving the elongation at break of the coating, but not the tensile strength. The reactive plasticizers, through chemical bonding, become part of the polymer curing network, increasing the molecular weight and cross-linking degree of the cured polyurethane resin, thereby correspondingly improving the tensile strength of the coating.

[0010] According to the single-component bituminous polyurethane waterproof coating of the present invention, the modified polyol is prepared from raw materials including polybutadiene polyol, acid anhydride and epoxy compound.

[0011] This invention prepares a modified polyol with a special "amphiphilic" structure using polybutadiene polyol, acid anhydride, and epoxy compound as raw materials. In this structure, the polybutadiene polyol provides a long and flexible nonpolar hydrocarbon chain, acting as an "oleophilic anchor" that can generate strong physical entanglement and van der Waals forces with the nonpolar asphalt molecules on the surface of asphalt rolls, greatly improving the wettability and compatibility of the coating with the asphalt substrate. Meanwhile, the acid anhydride and epoxy compound react with the terminal hydroxyl groups of the polybutadiene polyol to regenerate active hydroxyl groups at the other end of the molecular chain, which can participate in the main reaction of polyurethane. One end of the modified polyol firmly "grabs" the asphalt through nonpolar segments, while the other end is covalently bonded to the main network of the polyurethane resin through chemical bonds via active hydroxyl groups. This design fundamentally solves the problems of poor compatibility and additive migration caused by traditional physical blending methods, resulting in a strong chemical / physical dual bond between the coating and the asphalt substrate. This enhances the interfacial bonding strength and durability between the two, ensuring that the composite waterproof layer maintains excellent peel strength and structural integrity even under harsh environments such as thermal expansion and contraction and long-term immersion.

[0012] Preferably, the polybutadiene polyol has a number-average molecular weight of 1000-5000 and an average functionality of 2-3. Limiting the molecular weight of the polybutadiene polyol to 1000-5000 balances "affinity for asphalt" and "compatibility within the polyurethane system." Too low a molecular weight results in insufficient oleophilicity, while too high a molecular weight easily leads to phase separation and excessive viscosity. An average functionality of 2-3 endows the final polymer structure with tunability, allowing it to achieve excellent flexibility and elongation at break through linear segments, while also forming a cross-linked network through branching points to ensure strength and chemical resistance.

[0013] The molecular structure of the polybutadiene polyol is as follows: Where a = 0 - 0.2, b = 0.2 - 0.9, c = 0.1 - 0.6, a + b + c = 1, and n = 15 ~ 95.

[0014] The anhydride is an aliphatic or alicyclic anhydride, preferably one or more of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, dodecyl succinic anhydride, and n-dodecyl succinic anhydride. These flexible aliphatic or alicyclic anhydrides avoid the introduction of rigid benzene rings, which helps to maintain and improve the overall coating's flexibility and crack resistance at low temperatures.

[0015] The epoxy compound is an aliphatic or alicyclic compound without hydroxyl groups, and contains one or more epoxy groups, preferably one or more selected from the following: ethylene methyl neodecanoate, 1,2,7,8-diepoxyoctane, n-butyl glycidyl ether, diglycidyl 4,5-epoxytetrahydrophthalic acid, dicyclopentadiene epoxide, allyl glycidyl ether, octyl glycidyl ether, isooctyl glycidyl ether, and 1,2-epoxyhexadecane. Selecting specific hydroxyl-free epoxy compounds not only efficiently converts intermediate acids back into reactive hydroxyl groups, but their aliphatic structure also further enhances the flexibility of the molecular chain and reduces the viscosity of the system.

[0016] According to the single-component bituminous polyurethane waterproof coating of the present invention, the molar ratio of the polybutadiene polyol, the acid anhydride, and the epoxy compound is (1-1.05):(0.95-1):(1-1.05). This ratio ensures sufficient reaction of the carboxyl groups and avoids residual carboxyl groups affecting the reactivity.

[0017] According to the single-component asphalt-loving polyurethane waterproof coating of the present invention, the modified polyol includes one or more of modified polyol A, modified polyol B, and modified polyol C. The structural formula of modified polyol A is shown in Formula I below: Formula I, where a = 0 - 0.2, b = 0.2 - 0.9, c = 0.1 - 0.6, a + b + c = 1, and n = 15 - 95.

[0018] The structural formula of modified polyol B is shown in Formula II below: Equation II, where a = 0 - 0.2, b = 0.2 - 0.9, c = 0.1 - 0.6, a + b + c = 1, and n = 15 - 95.

[0019] The structural formula of the modified polyol C is shown in Formula III below: Equation III, where a = 0 - 0.2, b = 0.2 - 0.9, c = 0.1 - 0.6, a + b + c = 1, and n = 15 - 95.

[0020] According to the single-component asphalt-loving polyurethane waterproof coating of the present invention, the modified polyol is prepared as follows: the polybutadiene polyol is dehydrated (preferably vacuum dehydration, temperature 100-110℃, vacuum degree -0.1MPa, time 1-3h) and reacted with the acid anhydride at 60-90℃ for 2-4h; after the reaction is completed, the epoxy compound is added, stirred and heated to 120-130℃, a second catalyst is added and reacted for 2-4h; after the reaction is completed, a second solvent is added, stirred evenly, cooled and discharged for later use.

[0021] The first step of the modified polyol preparation method of this invention involves an esterification reaction at a relatively mild temperature of 60-90°C, ensuring high efficiency and avoiding damage to the polybutadiene backbone caused by high temperatures. It also prevents the esterification reaction between the carboxyl groups generated from the anhydride reaction and the hydroxyl groups of the polybutadiene polyol. Subsequently, in the second step, the temperature is increased to 120-130°C, providing sufficient activation energy for the more difficult reaction between carboxyl and epoxy groups, and introducing a catalyst, thus achieving a rapid and complete reaction. This process effectively avoids various side reactions that may occur with a one-pot reaction of all materials (such as epoxy self-polymerization and transesterification), ensuring the high purity and well-defined molecular structure of the target product (modified polyol). Finally, at the end of the reaction, a solvent is added for dilution, significantly reducing the viscosity of the product, transforming it from a difficult-to-handle viscous substance into an easily pumpable and mixable fluid, and greatly improving its dispersibility and processability in subsequent coating preparation.

[0022] According to the single-component asphalt-loving polyurethane waterproof coating of the present invention, the second catalyst is triphenylphosphine, and its addition amount is 1‰-5‰ of the total mass of the polybutadiene polyol, the acid anhydride and the epoxy compound.

[0023] In the second step of modified polyol preparation, the ring-opening addition reaction between carboxyl and epoxy groups is typically slow and requires high temperatures, easily triggering side reactions such as epoxy group self-polymerization. Triphenylphosphine, as a highly efficient nucleophilic catalyst, can significantly lower the activation energy of this specific reaction, promoting its rapid and complete occurrence under the set process conditions. This not only greatly shortens the reaction time, but more importantly, through its mild yet efficient catalytic action, it fundamentally inhibits the occurrence of side reactions, thereby significantly improving the purity and yield of the product.

[0024] The second solvent is the same as the first solvent, and its addition amount is 10-15% of the total mass of the polybutadiene polyol, the acid anhydride, the epoxy compound, and the first catalyst. Limiting the amount to 10-15% is sufficient to achieve effective viscosity reduction and pre-dispersion, while avoiding problems such as excessive VOC content in the final coating product, slow curing speed, or excessive shrinkage after film formation caused by excessive solvent.

[0025] According to the single-component bituminous polyurethane waterproof coating of the present invention, the reactive plasticizer includes one or more of epoxidized soybean oil and epoxidized fatty acid methyl ester.

[0026] Unlike traditional physically added plasticizers that are prone to migration and seepage (such as chlorinated paraffin or DOP), the reactive plasticizer used in this invention contains active epoxy groups in its molecules. These groups participate in the chemical reaction during polyurethane curing, covalently anchoring or locking themselves to the final polymer network framework. This chemical bonding fundamentally eliminates the possibility of plasticizer migration due to temperature changes, prolonged immersion in water, or contact with asphalt. This ensures the coating maintains its flexibility and crack resistance for a long time, preventing brittleness due to plasticizer loss. It also completely eliminates the risk of plasticizer migration to the coating-asphalt interface, forming a "separation layer." This guarantees the high peel strength between the waterproof coating and the asphalt membrane is maintained stably over a long period, even under high summer temperatures, significantly improving the reliability and durability of the entire composite waterproofing system.

[0027] According to the single-component bituminous polyurethane waterproof coating of the present invention, the diisocyanate is selected from one or more of hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate and toluene diisocyanate.

[0028] According to the single-component bituminous polyurethane waterproof coating of the present invention, the polyether polyol is selected from one or more polyether polyols with a hydroxyl value of 30-120 mgKOH / g and a functionality of 2-5.

[0029] According to the single-component bituminous polyurethane waterproof coating of the present invention, the polyether polyol includes polyether diol and polyether triol, and the weight ratio of polyether diol to polyether triol is 10:(5-10), preferably 10:(7-9).

[0030] According to the single-component bituminous polyurethane waterproof coating of the present invention, the latent curing agent is selected from one or more of aldehyde imine latent curing agents, ketimine latent curing agents, and oxazolidine latent curing agents.

[0031] Aldehyde imide latent curing agents can be isophorone diamine (IPDA)-based aldehyde imide, diethyltoluene diamine (DETDA)-based aldehyde imide, hexamethylene diamine (HMDA)-based aldehyde imide, etc.

[0032] Ketoimine latent curing agents can include isophorone diamine (IPDA) ketoimine, diethyltoluene diamine (DETDA) ketoimine, 1,2-propanediamine ketoimine, etc.

[0033] Oxazolidine latent curing agents can include the Incozol® series, Zoldine® MS-PLUS, and oxazolidines based on diethanolamine or triethanolamine.

[0034] All the latent curing agents described in this invention are commercially available. For example, they can be purchased from Suzhou Xiangyuan New Materials Co., Ltd. as the aldehyde-imide latent curing agent XYlink 401.

[0035] According to the single-component asphalt-loving polyurethane waterproof coating of the present invention, the pigments and fillers include fillers and pigments. The fillers are selected from one or more of nano-calcium carbonate, talc, fumed silica, barium sulfate, heavy calcium carbonate, light calcium carbonate and kaolin, with a particle size of 800 mesh to 3000 mesh. The pigments are selected from one or more of carbon black, iron oxide red, titanium dioxide, iron oxide yellow and composite emerald green.

[0036] According to the single-component bituminous polyurethane waterproof coating of the present invention, the first solvent is selected from one or more of trimethylbenzene, tetramethylbenzene, propylene glycol methyl ether acetate and butyl acetate.

[0037] The single-component asphalt-loving polyurethane waterproof coating according to the present invention further includes 1-5 parts by weight of other additives, wherein the other additives include one or more of dispersants, defoamers, latent curing agents, and hydrolysis accelerators; Preferably, the other additives include: 0.5-1 parts by weight of dispersant, 1-3 parts by weight of defoamer, and 0.1-0.5 parts by weight of latent curing agent and hydrolysis accelerator.

[0038] The dispersant is selected from nonionic dispersants, anionic dispersants, or combinations thereof, and can be BYK-199, BYK-110, Disuper S18, etc.

[0039] The defoamer is selected from silicone defoamers, mineral oil defoamers, or combinations thereof, and can be BYK-1786, BYK-052N, Zhonglianbang B313, Zhonglianbang 314, Zhonglianbang 315, etc.

[0040] The latent curing agent hydrolysis accelerator is selected from sulfonic acid hydrolysis accelerators, carboxylic acid hydrolysis accelerators, phosphoric acid hydrolysis accelerators, acid anhydride hydrolysis accelerators, organic complex hydrolysis accelerators, or combinations thereof. All latent curing agents described in this invention are commercially available. For example, they can be accelerator A-289 from Shandong Yihang New Material Technology Co., Ltd., or latent curing hydrolysis accelerator YG1101 from Shanghai Zhengui New Material Technology Co., Ltd.

[0041] According to a second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned single-component bituminous polyurethane waterproof coating, comprising the following steps: Polyether polyol, reactive plasticizer, and pigments and fillers are mixed and then dehydrated under vacuum. After dehydration is complete, add modified polyol, stir evenly and cool to 75-80℃, add diisocyanate, then heat to 75-85℃ and react for 2-4 hours; add the first catalyst and react for a period of time; then add the latent curing agent and continue to react for a period of time; finally add the first solvent.

[0042] The preparation method of this invention utilizes a vacuum dehydration step to eliminate water-induced side reactions at the source, laying a pure foundation for subsequent synthesis. Its unique stepwise temperature-controlled reaction strategy ensures the formation of the polyurethane prepolymer under stable and controllable conditions, thereby obtaining a core polymer with a well-defined structure and excellent performance. Furthermore, the orderly addition of the catalyst and latent curing agent balances production efficiency with the single-component storage stability of the product. The synergistic effect of this series of rigorous process designs ultimately and reliably produces a high-performance single-component bituminous polyurethane waterproof coating that combines long shelf life, excellent final performance, and good workability.

[0043] According to the preparation method of the single-component asphalt-loving polyurethane waterproof coating of the present invention, the vacuum dehydration temperature is 100-110℃, the vacuum degree is -0.1MPa, and the time is 1-3h.

[0044] According to the preparation method of the single-component asphalt-loving polyurethane waterproof coating of the present invention, the temperature is controlled at 70-80℃, a first catalyst is added, and the reaction is carried out for 0.5-2 hours; then a latent curing agent is added, and the reaction is continued for 0.5-2 hours.

[0045] According to the preparation method of the single-component asphalt-loving polyurethane waterproof coating of the present invention, the temperature is lowered to 65-70℃, a first solvent is added, and the reaction is carried out for 10-30 minutes.

[0046] The beneficial effects of this invention are: The single-component asphalt-friendly polyurethane waterproof coating provided by this invention introduces modified polyols and reactive plasticizers into a specific formulation system. The synergistic effect between the components makes the prepared waterproof coating not only have excellent physical properties (such as high tensile strength and high elongation at break), but more importantly, it can form a strong whole when combined with asphalt rolls, solving the fundamental problem of poor adhesion between traditional polyurethane coatings and asphalt substrates. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0048] The raw materials used in the following examples and comparative examples are sourced from the following sources: Polyether diol: DL-2000D, Shandong Lanxing Dongda Co., Ltd.; Polyether triol: EP330N, Shandong Lanxing Dongda Co., Ltd.; Isocyanate: HMDI; Modified polyol A: The structural formula is as follows: Where a=0.2, b=0.2, c=0.6, n=51.

[0049] The modified polyol A is prepared as follows: Polybutadiene polyol (molecular weight 2800, average functionality 2.5) is vacuum dehydrated at a temperature of 100-110℃, a vacuum degree of -0.1MPa, and a time of 3h. After dehydration, the molar ratio of n-dodecyl succinic anhydride to polybutadiene polyol is 0.98:1. The mixture is reacted at 80-85℃ for 2h. After the reaction, 1,2-epoxyhexadecane is added and mixed at a molar ratio of n-dodecyl succinic anhydride to 1,2-epoxyhexadecane of 0.98:1. Triphenylphosphine catalyst is added simultaneously (the amount added is 3‰ of the total mass of polybutadiene polyol, anhydride, and epoxy compound). The mixture is reacted at 120-130℃ for 4h. After the reaction, 10% of the mass of all reactants is added as solvent propylene glycol methyl ether acetate.

[0050] Modified polyol B: The structural formula is as follows: Where a=0.2, b=0.2, c=0.6, n=51.

[0051] The modified polyol B is prepared as follows: Polybutadiene polyol (molecular weight 2800, average functionality 2.5) is vacuum dehydrated at a temperature of 100-110℃, a vacuum degree of -0.1MPa, and a time of 3h. After dehydration, the molar ratio of n-dodecyl succinic anhydride to polybutadiene polyol is 0.98:1. The mixture is reacted at 80-85℃ for 2h. After the reaction, 1,2,7,8-diepoxyoctane is added and mixed at a molar ratio of n-dodecyl succinic anhydride to 1,2,7,8-diepoxyoctane of 0.98:1. Triphenylphosphine catalyst is added simultaneously (the amount added is 3‰ of the total mass of polybutadiene polyol, anhydride, and epoxy compound). The mixture is reacted at 120-130℃ for 4h. After the reaction, 10% of the mass of all reactants is added as solvent propylene glycol methyl ether acetate.

[0052] Modified polyol C: The structural formula is as follows: Where a=0.2, b=0.2, c=0.6, n=51.

[0053] The modified polyol C is prepared as follows: Polybutadiene polyol (molecular weight 2800, average functionality 2.5) is vacuum dehydrated at a temperature of 100-110℃, a vacuum degree of -0.1MPa, and a time of 3h. After dehydration, the molar ratio of methyl hexahydrophthalic anhydride to polybutadiene polyol is added at 0.98:1, and the mixture is reacted at 80-85℃ for 2h. After the reaction, dicyclopentadiene epoxide is added and mixed at a molar ratio of methyl hexahydrophthalic anhydride to dicyclopentadiene epoxide at 0.98:1. Triphenylphosphine catalyst is added simultaneously (the amount added is 3‰ of the total mass of polybutadiene polyol, anhydride, and epoxide). The mixture is reacted at 120-130℃ for 4h. After the reaction, 10% of the mass of all reactants is added as solvent propylene glycol methyl ether acetate.

[0054] Pigments and fillers, including: 800-mesh heavy calcium carbonate filler and 1250-mesh talc powder; pigments: carbon black and composite emerald green; Reactive plasticizer: epoxidized soybean oil; Catalyst: T12 organotin catalyst (dibutyltin dilaurate); Dispersant: DisuperS18, purchased from Guangzhou Core New Materials Technology Co., Ltd.; Defoamer: BYK-052N; All other unspecified raw materials can be obtained commercially.

[0055] Example 1 This embodiment provides a single-component asphalt-friendly polyurethane waterproof coating, which is prepared from the raw materials in the following Table 1 by weight.

[0056] This embodiment also provides a method for preparing the single-component asphalt-sensitive polyurethane waterproof coating, including the following steps: A. Add polyether polyol, plasticizer, pigment, filler, dispersant and defoamer to the reaction vessel, stir and heat to 105℃±3℃, and dehydrate under vacuum of -0.1MPa for 2 hours.

[0057] B. After dehydration is complete, add the modified polyol, stir evenly and cool to 75℃~80℃, add diisocyanate, and then heat to 80℃±2℃ and react for 3h.

[0058] C. Control the temperature at 75℃±2℃, add the catalyst, and react at 75℃±2℃ for 1 hour.

[0059] D. Control the temperature at 75℃±2℃, add the latent curing agent, and continue the reaction for 1 hour.

[0060] E. Cool to 65-70℃, add latent curing agent, hydrolysis accelerator and first solvent propylene glycol methyl ether acetate, and react for 20 minutes.

[0061] F. Control the temperature at 65℃±2℃, vacuum degas for 10 minutes, and discharge the material under nitrogen protection to obtain a single-component asphalt-friendly polyurethane waterproof coating.

[0062] Examples 2-7 Examples 2-7 each independently provide a single-component asphalt-friendly polyurethane waterproof coating, prepared from the raw materials in the following Table 1 by weight.

[0063] Examples 2-7 also provide independent preparation methods for the single-component asphalt-loving polyurethane waterproof coating, which are the same as those in Example 1.

[0064] Comparative Examples 1-7 Comparative Examples 1-7 each independently provide a single-component asphalt-friendly polyurethane waterproof coating, prepared from the raw materials in parts by weight as shown in Table 1 below.

[0065] Comparative Examples 1-7 also provide independent preparation methods for the single-component asphalt-loving polyurethane waterproof coating, which are the same as those in Example 1.

[0066] Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 DL-2000D 100 100 100 100 100 100 100 100 100 100 100 100 100 100 EP330N 80 80 80 80 80 80 80 80 80 80 80 80 80 80 Modified polyol A 75 0 0 50 100 75 75 0 0 75 40 110 75 75 Modified polyol B 0 75 0 0 0 0 0 0 0 0 0 0 0 0 Modified polyol C 0 0 75 0 0 0 0 0 0 0 0 0 0 0 Epoxidized soybean oil 150 150 150 150 150 100 300 150 0 0 150 150 50 350 52# Chlorinated Paraffin 0 0 0 0 0 0 0 0 150 150 0 0 0 0 DisuperS18 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 BYK-052N 2 2 2 2 2 2 2 2 2 2 2 2 2 2 800 mesh calcium carbonate 200 280 280 280 280 200 200 280 280 280 280 280 200 200 1250 mesh talc 150 170 170 170 170 150 150 170 170 170 170 170 150 150 carbon black 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 Composite Emerald Green 7 7 7 7 7 7 7 7 7 7 7 7 7 7 HMDI 58 58 58 58 58 58 58 58 58 58 58 58 58 58 T12 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Latent curing agent 34 34 34 34 34 34 34 34 34 34 34 34 34 34 Latent curing agent hydrolysis accelerator 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Propylene glycol methyl ether acetate 50 50 50 50 50 50 50 50 50 50 50 50 50 50 Test section The relevant properties of the waterproof coatings prepared in Examples 1-7 and Comparative Examples 1-7 were tested using the test methods of GB / T 16777-2008, GB / T 19250-2013, and GB 55030-2022. For the peel strength test method GB / T 328.20-2007, the polyurethane waterproof coating and asphalt waterproof membrane were combined as follows: 24 hours after the polyurethane waterproof coating was applied and formed a film, the self-adhesive waterproof membrane was peeled off and then bonded to the polyurethane waterproof coating. The membrane was then cured in a standard environment for 168 hours before testing.

[0067] The test results are shown in Table 2 below: Table 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Elongation at break (%) 766 688 669 655 823 797 698 622 645 789 632 858 522 902 Tensile strength (MPa) 2.59 2.62 2.65 2.67 2.22 2.48 2.71 2.64 2.57 2.22 2.64 1.97 3.01 2.22 Tear strength (N / mm) 20.0 20.4 20.6 20.5 18.9 18.9 20.4 20.2 19.8 18.5 19.3 18.3 21.8 17.7 Coil-coated composite peel strength (N / mm) (failure mode) 2.76 (100% asphalt membrane cohesive failure) 2.68 (100% cohesive failure of bituminous roofing membrane) 2.71 (Cohesive failure of 100% bituminous roofing membrane) 2.57 (100% asphalt membrane cohesive failure) 2.85 (cohesive failure of 100% bituminous membrane rolls) 2.80 (100% asphalt membrane cohesive failure) 2.32 (Cohesive failure of 100% bituminous membrane rolls) 1.57 (60% cohesion failure) 1.23 (40% cohesion failure) 1.70 (80% cohesion failure) 1.62 (60% cohesion failure) 2.68 (100% cohesive failure of bituminous roofing membrane) 2.83 (100% asphalt membrane cohesive failure) 1.88 (80% cohesion failure) Acid treatment strength retention rate (%) 95 94 95 90 97 92 96 86 84 87 88 98 96 90 Alkali treatment strength retention rate (%) 92 93 93 90 95 90 93 85 83 86 87 97 95 87 Heat treatment strength retention rate (%) 91 92 91 89 94 89 91 82 81 84 86 96 94 85 Water absorption rate (%) 1.2 1.2 1.3 1.5 0.9 1.2 1.3 3.4 3.5 2.4 1.7 0.7 1.1 1.4 As can be seen from the experimental data in Table 2, the single-component bituminous polyurethane waterproof coating of this invention introduces modified polyols with specific structures and reactive plasticizers into the polyurethane system, successfully solving the problems of poor adhesion between traditional polyurethane coatings and bituminous membranes and easy peeling after thermal aging. Data shows that the coating prepared in the embodiments of this invention not only has excellent mechanical properties, but also significantly improved composite peel strength with bituminous membranes, achieving ideal 100% cohesive failure of the bituminous membrane, while maintaining high-strength and stable adhesion under acid, alkali, and thermal aging conditions.

[0068] Compared to Comparative Example 1 without the addition of modified polyol, Example 1 with the addition of modified polyol showed higher strength retention rates under acid, alkali, and heat treatments, and also exhibited better peel performance with asphalt rolls.

[0069] Compared to Comparative Examples 2 and 3, Example 1 exhibits significant advantages in adhesion and durability to asphalt roofing membranes. Example 1 uses both modified polyol A and a reactive plasticizer (epoxidized soybean oil); Comparative Example 2 does not contain modified polyol and uses a conventional plasticizer (chlorinated paraffin) instead of the reactive plasticizer; while Comparative Example 3 uses the same modified polyol A as Example 1, it still employs a conventional plasticizer (chlorinated paraffin). The comparative results show that the peel strength of the roll-to-coat composite of Example 1 is much higher than that of Comparative Examples 2 and 3, and it achieves the ideal 100% cohesive failure of the roofing membrane, proving its strong adhesion. In addition, Example 1 has a higher strength retention rate and significantly lower water absorption rate after acid, alkali, and heat treatment. This indicates that the synergistic effect of modified polyol and reactive plasticizer can improve the adhesion strength and durability of the coating to the asphalt substrate.

[0070] The comparison results between Example 1 and Comparative Examples 4 and 5 show that only within the specified ratio range of the modified polyol (as in Example 1) can the coating achieve high and durable adhesion strength to the asphalt membrane while maintaining its excellent mechanical properties. Insufficient modified polyol (Comparative Example 4) reduces the strength retention rate after acid, alkali, and heat treatment, as well as the peel performance with the asphalt membrane. Excessive use and insufficient plasticizer (Comparative Example 5) severely impair the tensile strength of the material, resulting in a tensile strength lower than the national standard requirements.

[0071] The comparison results between Example 1 and Comparative Examples 6 and 7 show that when the amount of reactive plasticizer is too small (Comparative Example 6), although the tensile strength is high, the elongation at break of the coating will be significantly reduced, resulting in insufficient flexibility and brittleness of the material. When the amount is too large (Comparative Example 7), the material will soften excessively, not only reducing the tensile strength and the peel strength from the asphalt membrane, but also causing a comprehensive deterioration in its resistance to acid, alkali, and heat aging. In contrast, Example 1 of the present invention achieves an excellent balance in various performance indicators, ensuring both high strength and high flexibility, and achieving a strong and durable bond with the asphalt membrane.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A one-component bituminous polyurethane waterproof coating, characterized in that, The product comprises the following raw materials: 30-70 parts by weight of diisocyanate, 100-300 parts by weight of polyether polyol, 50-100 parts by weight of modified polyol, 100-300 parts by weight of reactive plasticizer, 15-50 parts by weight of latent curing agent, 0.1-0.5 parts by weight of first catalyst, 100-550 parts by weight of pigments and fillers, and 30-80 parts by weight of first solvent; wherein the reactive plasticizer comprises one or more of epoxidized soybean oil and epoxidized fatty acid methyl ester; The modified polyol is prepared from polybutadiene polyol, acid anhydride and epoxy compound as raw materials; the molar ratio of the polybutadiene polyol, the acid anhydride and the epoxy compound is (1-1.05):(0.95-1):(1-1.05). The molecular structure of the polybutadiene polyol is as follows: Where a = 0 - 0.2, b = 0.2 - 0.9, c = 0.1 - 0.6, a + b + c = 1, and n = 15 ~ 95.

2. The single-component bituminous polyurethane waterproof coating according to claim 1, characterized in that, The polybutadiene polyol has a number-average molecular weight of 1000-5000 and an average functionality of 2-3. The acid anhydride is an aliphatic acid anhydride or an alicyclic acid anhydride; The epoxy compound is an aliphatic or alicyclic compound that does not contain hydroxyl groups and contains one or more epoxy groups.

3. The single-component bituminous polyurethane waterproof coating according to claim 2, characterized in that, The acid anhydride is one or more of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, dodecyl succinic anhydride, and n-dodecyl succinic anhydride; the epoxy compound is one or more of neodecanoic acid epoxy methyl ester, 1,2,7,8-diepoxy octane, n-butyl glycidyl ether, 4,5-epoxy tetrahydrophthalic acid diglycidyl ester, dicyclopentadiene epoxide, allyl glycidyl ether, octyl glycidyl ether, isooctyl glycidyl ether, and 1,2-epoxy hexadecane.

4. The single-component bituminous polyurethane waterproof coating according to claim 2, characterized in that, The modified polyol is prepared as follows: the polybutadiene polyol is dehydrated and reacted with the acid anhydride at 60-90℃ for 2-4 hours; after the reaction is completed, the epoxy compound is added, stirred and heated to 120-130℃, the second catalyst is added and reacted for 2-4 hours; after the reaction is completed, the second solvent is added, stirred evenly, cooled and discharged for later use.

5. The single-component bituminous polyurethane waterproof coating according to claim 4, characterized in that, The second catalyst is triphenylphosphine, and its addition amount is 1‰-5‰ of the total mass of the polybutadiene polyol, the acid anhydride and the epoxy compound. The second solvent is the same as the first solvent, and its addition amount is 10-15% of the total mass of the polybutadiene polyol, the acid anhydride, the epoxy compound and the first catalyst.

6. The single-component bituminous polyurethane waterproof coating according to claim 1, characterized in that, The diisocyanate is selected from one or more of hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, and toluene diisocyanate; And / or, the polyether polyol is selected from one or more polyether polyols with a hydroxyl value of 30-120 mgKOH / g and a functionality of 2-5; And / or, the latent curing agent is selected from one or more of aldehyde imine latent curing agents, ketimine latent curing agents, and oxazolidine latent curing agents; And / or, the pigments and fillers include fillers and pigments, wherein the fillers are selected from one or more of nano-calcium carbonate, talc, fumed silica, barium sulfate, heavy calcium carbonate, light calcium carbonate, and kaolin, and the particle size is 800 mesh to 3000 mesh; the pigments are selected from one or more of carbon black, iron oxide red, titanium dioxide, iron oxide yellow, and composite emerald green; And / or, the first solvent is selected from one or more of methylbenzene, tetrabenzene, propylene glycol methyl ether acetate and butyl acetate.

7. The single-component bituminous polyurethane waterproof coating according to claim 1, characterized in that, It also includes 1-5 parts by weight of other additives, which include one or more of dispersants, defoamers, latent curing agents, and hydrolysis accelerators.

8. The method for preparing the single-component bituminous polyurethane waterproof coating according to claim 7, wherein the other additives include: Dispersant 0.5-1 parts by weight, defoamer 1-3 parts by weight, and latent curing agent and hydrolysis accelerator 0.1-0.5 parts by weight.

9. The method for preparing the single-component bituminous polyurethane waterproof coating according to any one of claims 1-8, characterized in that, Includes the following steps: Polyether polyol, reactive plasticizer, and pigments and fillers are mixed and then dehydrated under vacuum. After dehydration is complete, add modified polyol, stir evenly and cool to 75-80℃, add diisocyanate, then heat to 75-85℃ and react for 2-4 hours; add the first catalyst and react for a period of time; then add the latent curing agent and continue to react for a period of time; finally add the first solvent.

10. The preparation method of the single-component bituminous polyurethane waterproof coating according to claim 9, characterized in that, The vacuum dehydration temperature is 100-110℃, the vacuum degree is -0.1MPa, and the time is 1-3h; And / or, control the temperature at 70-80℃, add the first catalyst, and react for 0.5-2 hours; then add the latent curing agent and continue the reaction for 0.5-2 hours; And / or, cool to 65-70℃, add the first solvent, and react for 10-30 minutes.

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