High-strength one-component polyurethane waterproof coating

Abstract

This invention relates to the field of waterproof coating technology and discloses a high-strength single-component polyurethane waterproof coating, comprising the following components by mass percentage: 32%~35% polyether polyol-toluene diisocyanate-terminated NCO prepolymer, 1.0%~1.4% bis(3-aminopropyl)disiloxane, 2.0%~2.5% latent curing agent; 0.7%~0.9% 2,5-furandimethyl alcohol; 38%~40% compound filler; 6.5%~7.5% low-aromatic environmentally friendly heavy aromatic solvent S-150; 0.25%~0.35% organic bismuth catalyst; 0.5%~0.7% polyether-polyester grafted modified polysiloxane defoamer; and 1.0%~1.2% compound antioxidant. This invention has the effect of improving the strength and toughness of the waterproof coating.

Description

Technical Field

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

[0002] Single-component polyurethane waterproof coatings have become one of the mainstream products in the field of building waterproofing due to their advantages such as convenient construction, no measurement error, and wide adaptability. They are widely used in waterproofing projects for roofs, basements, tunnels, bridges, and other parts of various buildings.

[0003] As key projects continue to demand higher waterproofing performance, existing single-component polyurethane waterproof coatings have gradually revealed many shortcomings. In particular, the tensile strength of conventional waterproof coatings is generally difficult to exceed 6.5 MPa, and while the strength is improved, the elongation at break often decreases, resulting in a technical contradiction of "high strength and low toughness," which cannot meet the long-term use needs of key projects such as railways and bridge decks. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength single-component polyurethane waterproof coating that improves the strength and toughness of waterproof coatings.

[0005] The above-mentioned technical objective of this invention is achieved through the following technical solution: a high-strength single-component polyurethane waterproof coating, comprising the following components by mass percentage: 32%~35% polyether polyol-toluene diisocyanate-terminated NCO prepolymer, 1.0%~1.4% bis(3-aminopropyl)disiloxane, 2.0%~2.5% latent curing agent; 0.7%~0.9% 2,5-furandimethyl alcohol; 38%~40% compound filler; 6.5%~7.5% low-aromatic environmentally friendly heavy aromatic solvent S-150; 0.25%~0.35% organic bismuth catalyst; 0.5%~0.7% polyether-polyester grafted modified polysiloxane defoamer; and 1.0%~1.2% compound antioxidant.

[0006] The polyether polyol-toluene diisocyanate-terminated NCO prepolymer is prepared by reacting polyether polyol N220 and TDI-80 at a mass ratio of 1:0.35~0.40, and the mass fraction of the NCO in the prepolymer is 6.0%~8.0%.

[0007] A further provision of the present invention includes 0.6% to 1.0% of a terminal amino hyperbranched polysiloxane, wherein the terminal amino hyperbranched polysiloxane has a branching degree of 2.5 to 3.0, a number average molecular weight of 1500 to 2500, and a terminal amino content of 0.8 to 1.2 mmol / g.

[0008] A further feature of the present invention is that the latent curing agent is methyl ethyl ketone imine modified isophorone diamine (IPDA) ketone imine, wherein the methyl ethyl ketone imine modified IPDA ketone imine (MEI-K) has an amine value of 280~320 mgKOH / g and a hydrolysis rate of 0.02~0.03 mol / (L·h) (25℃, relative humidity 60%).

[0009] A further provision of the present invention is that the compound filler is composed of heavy calcium carbonate, calcined kaolin and carbon black in a mass ratio of 3:1:0.05; and the compound antioxidant is composed of hindered phenolic antioxidant 1010 and phosphite antioxidant 168 in a mass ratio of 1:1.

[0010] A further provision of the present invention is that the organic bismuth catalyst is bismuth neodecanoate.

[0011] A further provision of the present invention is a method for preparing a high-strength single-component polyurethane waterproof coating, comprising the following steps:

[0012] (1) Add polyether polyol N220, bis(3-aminopropyl)disiloxane (APDS), 2,5-furandiethanol (FDM), and compound filler into a reactor, start stirring, adjust the speed to 800~1000 r / min, raise the temperature to 115~118℃, and dehydrate under vacuum conditions of -0.096~-0.098 MPa for 2.5 h to obtain a dehydrated mixture;

[0013] (2) Cool the dehydrated mixture obtained in step (1) to 78~82℃, add TDI-80, low aromatic environmentally friendly heavy aromatic solvent S-150 and polyether-polyester grafted modified polysiloxane defoamer, purge with nitrogen for protection, adjust the stirring speed to 1200~1500r / min, and react at a constant temperature for 2h to obtain silicon hybrid NCO polyurethane prepolymer;

[0014] (3) Add amino-terminated hyperbranched polysiloxane (HBP-Si-NH2), organic bismuth catalyst and compound antioxidant to the silicon hybrid NCO polyurethane prepolymer obtained in step (2), adjust the stirring speed to 2000 r / min, and stir under vacuum for 30 min to ensure that the system is uniform and free of bubbles.

[0015] (4) Add methyl ethyl ketone imine modified IPDA ketone imine (MEI-K) to the mixture obtained in step (3), continue vacuum stirring for 20 min, then stop stirring, cool down to below 40°C under nitrogen protection, discharge the material, seal and package it to obtain the high-strength environmentally friendly single-component polyurethane waterproof coating.

[0016] The present invention is further configured such that the nitrogen gas introduction rate in step (2) is 0.8~1.2 L / min, and the temperature fluctuation of the system during the reaction is controlled to not exceed ±2℃.

[0017] The present invention is further configured such that: in step (3), the vacuum degree is maintained at -0.096 to -0.098 MPa, and the system state is observed during the stirring process to ensure that no bubbles are generated.

[0018] A further feature of the present invention is that the water contact angle of the waterproof coating is ≥108°, the adhesion strength to a damp substrate is ≥1.6MPa, and it can withstand water immersion for 240 hours without delamination or blistering.

[0019] The beneficial effects of this invention are:

[0020] 1. This invention achieves a leap in comprehensive performance through the scientific compounding and synergistic reaction of its components, forming a structurally stable and performance-balanced cross-linking curing system. This is achieved from multiple levels, including molecular structure design, cross-linking network construction, interfacial interaction regulation, and curing kinetic matching. The polyether polyol-toluene diisocyanate-terminated NCO prepolymer serves as the main film-forming substance, providing the coating with basic mechanical strength, adhesion, and structural stability. Its terminal isocyanate groups can undergo a stepwise cross-linking reaction with chain extenders, latent curing agents, and other active hydrogen components to form a three-dimensional network polymer structure, providing the film-forming basis and overall skeletal support for the waterproof coating.

[0021] APDS and FDM form a complementary and synergistic chain-extending mechanism. As a linear diaminosiloxane chain extender, APDS possesses highly reactive primary amino groups (-NH2) at both ends of its molecule. These groups rapidly undergo addition reactions with the isocyanate groups (-NCO) of the NCO-terminated NCO prepolymer of polyether polyol-TDI, forming stable urea bonds (-NH-CO-NH-). The Si-O-Si siloxane segments in its main chain exhibit high bond energy and low internal rotation barriers, enabling the formation of flexible segment regions within the crosslinking network. This effectively alleviates internal stress generated during curing, endowing the coating with excellent flexibility, resilience, and... The low-temperature crack resistance, combined with the low surface energy of the Si-O-Si segments, can initially improve the hydrophobicity and water resistance of the coating film. FDM, as a rigid bio-based chain extender, allows the dihydroxyl (-OH) groups in its molecule to react with the -NCO groups of the prepolymer in a urethane ester reaction, embedding the rigid conjugated furan ring structure into the hard segment region of the polyurethane. The conjugation effect of the furan ring and the strong intermolecular hydrogen bonding significantly improve the modulus and cohesive strength of the crosslinked network, greatly enhancing the tensile strength and hardness of the coating film and compensating for the insufficient strength of the single APDS chain extender system. When the two work synergistically, the flexible siloxane segments of APDS and the rigid furan rings of FDM form a "soft segment-hard segment" microphase separation structure. The flexible segments are responsible for dispersing stress and improving toughness, while the rigid segments are responsible for supporting strength and improving rigidity, achieving an initial balance between coating strength and toughness, and simultaneously improving the strength and toughness of the waterproof coating.

[0022] 2. In this invention, the terminal amino hyperbranched polysiloxane (HBP-Si-NH2) serves as a multi-point crosslinking and structure-regulating component, forming a linear-hyperbranched interpenetrating silicon-nitrogen crosslinking network with APDS and FDM, further optimizing the system structure and performance. HBP-Si-NH2 possesses a highly branched spatial structure with numerous terminal amino groups distributed on its molecular surface. These terminal amino groups can undergo multi-point addition reactions with the -NCO groups of the prepolymer and the residual active groups after the APDS reaction, forming three-dimensional cross-linking nodes. Its branched structure can interpenetrate and entangle with the linear siloxane segments of APDS, constructing an interpenetrating network structure of "linear silicon nitrogen chain - hyperbranched silicon node". This structure can significantly increase the cross-linking density of the entire system, further enhancing the tensile strength, cohesive strength, and water resistance of the coating film. On the other hand, through the steric hindrance effect of the hyperbranched structure, it can inhibit the excessive migration and aggregation of APDS molecular chains, preventing the siloxane components from leaching and oil leakage, thus improving the stability of the system. At the same time, the hyperbranched structure of HBP-Si-NH2 can effectively release the internal stress generated during the curing process, alleviate the brittleness caused by the rigid structure of FDM, and further improve the low-temperature crack resistance of the coating film (achieving no cracks when bending at -30℃). Its thixotropic properties can also significantly improve the vertical anti-sagging performance of the coating film, enabling 2mm thick coatings to be applied without sagging or dripping. In addition, the terminal amino group of HBP-Si-NH2 has slightly lower reactivity than the primary amino group of APDS, and can form a gradient chain extension reaction with APDS, avoiding the reaction from being too violent and causing the system to gel. At the same time, it extends the sealed storage period of the waterproof coating, extending the storage period from the conventional 12 months to more than 15 months.

[0023] 3. This invention incorporates methyl ethyl ketone imine-modified IPDA ketone imine (MEI-K) as a staged amine-releasing latent curing agent, achieving precise curing kinetic matching with the aforementioned ternary chain extender system, resulting in full-humidity, bubble-free, and uniform curing. As a sterically hindered latent curing agent, MEI-K exhibits good stability under dry storage conditions, does not react prematurely with the prepolymer, and effectively ensures the storage stability of the system. When exposed to moisture in the construction environment, MEI-K undergoes a controlled hydrolysis reaction, releasing the IPDA alicyclic amine active component stepwise. Its amine release rate is well-adapted to environmental humidity and temperature—in low humidity environments, the amine release rate is slower, preventing surface cracking caused by excessively rapid surface drying while ensuring rapid film formation on the surface; in high humidity environments, the amine release rate is moderately accelerated, ensuring complete deep curing and avoiding foaming defects caused by excessive moisture. The IPDA alicyclic amine released by MEI-K can undergo cross-linking reactions with the residual -NCO groups in the prepolymer, as well as the residual amino groups in APDS and HBP-Si-NH2, further improving the cross-linking network and enhancing the density and mechanical properties of the coating film. More importantly, the graded amine release characteristics of MEI-K synergize with the gradient chain extension reactions of APDS and HBP-Si-NH2 to achieve a three-stage gradient curing process: rapid surface curing by MEI-K to achieve surface drying and prevent contamination during construction; linear chain extension by APDS to build the main strength and toughness; and multi-point cross-linking by HBP-Si-NH2 to achieve dense reinforcement in the deep layer, avoiding defects such as internal porosity, pinholes, and bubbles during thick coating construction.

[0024] 4. This invention constructs a quaternary synergistic system of bis(3-aminopropyl)disiloxane (APDS), 2,5-furandimethylethanol (FDM), terminal amino hyperbranched polysiloxane (HBP-Si-NH2), and methyl ethyl ketone imine modified IPDA ketone imine (MEI-K). Through the synergistic effect between molecules, the quaternary system achieves a synergistic leap in multi-dimensional performance, forming a comprehensive advantage of "high strength, high toughness, water resistance, weather resistance, construction adaptability, and storage stability". From a chemical bonding perspective, APDS, FDM, HBP-Si-NH2, and MEI-K all form stable chemical bonds with the prepolymer through active groups, constructing a unified three-dimensional cross-linked network that avoids component delamination and migration, thus improving system stability. From a spatial structure perspective, linear APDS, rigid FDM, and hyperbranched HBP-Si-NH2 form complementary spatial structures, ensuring both the rigidity and strength of the network while also considering flexibility and density. From a curing kinetics perspective, the stepwise amine release of MEI-K and the... The precise matching of gradient reactions and the highly selective catalysis of the organic bismuth catalyst (bismuth neodecanoate only catalyzes the reaction of -NCO with -OH and -NH2, and does not catalyze the foaming side reaction of -NCO with water) further ensure the stability and foam-free nature of the curing process. From the perspective of interfacial performance, the siloxane segments of APDS and HBP-Si-NH2 migrate to the coating surface to form a low surface energy hydrophobic layer. Combined with the dense network formed after MEI-K curing, it significantly improves the hydrophobicity (water contact angle ≥108°) and water resistance of the coating (no debonding or blistering after 240h of water immersion).

[0025] Therefore, the quaternary synergistic system achieves comprehensive synergistic effects of "chain extension and reinforcement, structural regulation, gradient curing, and interface optimization" through precise matching and synergistic effects of each component. Ultimately, it increases the tensile strength of the waterproof coating to over 7.2 MPa and maintains the elongation at break at over 550%. It also possesses excellent properties such as low-temperature crack resistance at -30℃, anti-sagging on 2mm vertical surfaces, application under all humidity conditions, no foaming in thick coatings, environmental friendliness without heavy metals, and long shelf life. Compared with existing technologies using single chain extenders and single latent curing agents, it has significant substantial features and progress. Moreover, the quaternary synergistic combination and its mechanism of action have not been disclosed in existing patents, effectively avoiding the risk of equivalent infringement. It provides reliable technical support for the high-performance, environmentally friendly, and engineering applications of waterproof coatings. Detailed Implementation

[0026] The technical solution of the present invention will now be clearly and completely described with reference to specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] All raw materials used in the following examples are commercially available industrial products and conform to the specifications defined in the claims. Unless otherwise specified, they are all operated according to conventional processes. Performance tests are all performed in accordance with GB / T 19250-2013 "Polyurethane Waterproof Coatings", JC / T 1066-2008 "Polymer Emulsions for Building Waterproof Coatings" and the indicators defined in the claims to ensure the accuracy and comparability of the test results.

[0028] I. Raw Material Specifications

[0029] Polyether polyol-TDI-terminated NCO prepolymer: It is prepared by reacting polyether polyol N220 and TDI-80 at a mass ratio of 1:0.35~0.40, with a -NCO mass fraction of 6.0%~8.0%; among which, TDI-80 (full name toluene diisocyanate 80 / 20) is the most mainstream diisocyanate raw material in the polyurethane industry, and its core is a mixture of 80% 2,4-TDI + 20% 2,6-TDI;

[0030] Bis(3-aminopropyl)disiloxane (APDS): Amine value 320~340 mgKOH / g, purity ≥99%;

[0031] 2,5-Furanyldiethanol (FDM): Purity ≥99%, hydroxyl value 180~200mgKOH / g;

[0032] Amino-terminated hyperbranched polysiloxane (HBP-Si-NH2): branching degree 2.5~3.0, number average molecular weight 1500~2500, amino-terminated content 0.8~1.2 mmol / g;

[0033] Methyl ethyl ketone imine modified isophorone diamine ketone imine (IPDA-MEK ketone imine for short): is a diketone imine generated by the dehydration condensation reaction of isophorone diamine (IPDA) and methyl ethyl ketone (MEK, butanone) (both primary amino groups of IPDA are capped by MEK); amine value 280~320 mgKOH / g, hydrolysis rate at 25℃ and 60% relative humidity is 0.02~0.03 mol / (L·h);

[0034] The compound filler is composed of heavy calcium carbonate, calcined kaolin and carbon black in a mass ratio of 3:1:0.05. The heavy calcium carbonate has a particle size of 3000 mesh and the calcined kaolin has a particle size of 2000 mesh.

[0035] S-150, a low-aromatic and environmentally friendly heavy aromatic solvent: aromatic content ≤10%, VOC content ≤10g / L;

[0036] Organic bismuth catalyst: bismuth neodecanoate, purity ≥98%;

[0037] Polyether-polyester grafted modified polysiloxane defoamer: solid content 50%, compatibility grade 1 (fully compatible with polyurethane and siloxane systems).

[0038] Compound antioxidants: Hindered phenolic antioxidant 1010 and phosphite antioxidant 168 are compounded at a mass ratio of 1:1, and the purity of both is ≥99%.

[0039] II. Performance Testing Methods

[0040] 1. Tensile strength and elongation at break: tested using a universal testing machine at a tensile rate of 500 mm / min, with 3 specimens tested per group and the average value taken;

[0041] 2. Low temperature bending performance: After being placed at a constant temperature of -30℃ for 2 hours, a bending tester was used to test the bending angle of 180° and observe whether cracking occurred.

[0042] 3. Anti-sagging performance of facade: 2mm thick coating, placed at 25℃ and 60% relative humidity for 24 hours, observe whether there is sagging or dripping;

[0043] 4. Water contact angle: Tested using a contact angle measuring instrument at a temperature of 25℃, and the average value of the test values ​​at 3 different points was taken;

[0044] 5. Bond strength to damp substrate: The substrate is concrete (moisture content 10%~15%), tested using a universal testing machine at a tensile rate of 10mm / min;

[0045] 6. Water immersion resistance: Immerse the sample in distilled water at 25℃ for 240 hours and observe whether it debonds or blisters, and test the tensile strength retention rate;

[0046] 7. Storage period: Store in a sealed state at a constant temperature of 25°C, observe changes in viscosity, whether the system separates into layers or gels, and record the storage stability time;

[0047] 8. Construction adaptability: Apply the material at relative humidity of 20%, 60%, and 90% respectively, and observe the surface drying time, complete drying time, and film formation state to determine whether blistering or pinholes occur.

[0048] III. Examples

[0049] Example 1

[0050] A high-strength, single-component polyurethane waterproof coating is prepared for a total volume of 100 kg. The specific weights of each component are as follows:

[0051] Polyether polyol-TDI-NCO prepolymer 32.0kg, APDS 1.2kg, FDM 0.8kg, HBP-Si-NH2 0.8kg, MEI-K 2.3kg, compound filler 39.2kg, low aromatic environmentally friendly heavy aromatic solvent S-150 6.8kg, bismuth neodecanoate 0.32kg, polyether-polyester grafted modified polysiloxane defoamer 0.58kg, compound antioxidant 1.0kg.

[0052] Preparation method:

[0053] (1) Add polyether polyol N220, APDS, FDM and compound filler to the reactor, start stirring, adjust the speed to 900 r / min, raise the temperature to 116℃, and dehydrate for 2.5 h under vacuum of -0.097 MPa to obtain dehydrated mixture;

[0054] (2) Cool the dehydrated mixture obtained in step (1) to 80°C, add TDI-80, low aromatic environmentally friendly heavy aromatic solvent S-150 and polyether-polyester grafted modified polysiloxane defoamer, purge with nitrogen (nitrogen purging rate 1.0 L / min), adjust the stirring speed to 1300 r / min, and react at a constant temperature for 2 h to obtain silicon hybrid NCO polyurethane prepolymer;

[0055] (3) Add HBP-Si-NH2, bismuth neodecanoate and compound antioxidant to the silicon hybrid NCO polyurethane prepolymer obtained in step (2), adjust the stirring speed to 2000 r / min, and stir for 30 min under a vacuum of -0.097 MPa to ensure that the system is uniform and free of bubbles.

[0056] (4) Add MEI-K to the mixture obtained in step (3), continue vacuum stirring for 20 minutes, then stop stirring, cool down to below 40°C under nitrogen protection, discharge the material, seal and package it to obtain the high-strength single-component polyurethane waterproof coating.

[0057] Performance test results: tensile strength 7.3MPa, elongation at break 560%, no cracks after bending at -30℃, no sagging on 2mm vertical surfaces, water contact angle 110°, adhesion strength on damp substrate 1.7MPa, no delamination or blistering after 240h water immersion, tensile strength retention rate 96%, sealed storage period 16 months, no blistering or pinholes during construction at 20%~90% relative humidity, surface drying time 2.5h, complete drying time 24h.

[0058] Example 2

[0059] A high-strength, single-component polyurethane waterproof coating is prepared for a total volume of 100 kg. The specific weights of each component are as follows:

[0060] Polyether polyol-TDI-terminated NCO prepolymer 33.0kg, APDS 1.0kg, FDM 0.7kg, HBP-Si-NH2 0.6kg, MEI-K 2.0kg, compound filler 39.0kg, low-aromatic environmentally friendly heavy aromatic solvent S-150 7.0kg, bismuth neodecanoate 0.25kg, polyether-polyester grafted modified polysiloxane defoamer 0.5kg, compound antioxidant 1.0kg.

[0061] Preparation method (same as in Example 1):

[0062] (1) Add polyether polyol N220, APDS, FDM and compound filler to the reactor, start stirring, adjust the speed to 800 r / min, raise the temperature to 115℃, and dehydrate for 2.5 h under vacuum of -0.096 MPa to obtain dehydrated mixture;

[0063] (2) Cool the dehydrated mixture obtained in step (1) to 78°C, add TDI-80, low aromatic environmentally friendly heavy aromatic solvent S-150 and polyether-polyester grafted modified polysiloxane defoamer, purge with nitrogen (nitrogen purging rate 0.8 L / min), adjust the stirring speed to 1200 r / min, and react at a constant temperature for 2 h to obtain silicon hybrid NCO polyurethane prepolymer;

[0064] (3) Add HBP-Si-NH2, bismuth neodecanoate and compound antioxidant to the silicon hybrid NCO polyurethane prepolymer obtained in step (2), adjust the stirring speed to 2000 r / min, and stir for 30 min under vacuum of -0.096 MPa to ensure that the system is uniform and free of bubbles.

[0065] (4) Add MEI-K to the mixture obtained in step (3), continue vacuum stirring for 20 minutes, then stop stirring, cool down to below 40°C under nitrogen protection, discharge the material, seal and package it to obtain the high-strength single-component polyurethane waterproof coating.

[0066] Performance test results: tensile strength 7.2MPa, elongation at break 550%, no cracks after bending at -30℃, no sagging on 2mm vertical surfaces, water contact angle 108°, adhesion strength to damp substrate 1.6MPa, no delamination or blistering after 240h water immersion, tensile strength retention rate 95%, sealed storage period 15 months, no blistering or pinholes during application at 20%~90% relative humidity, surface drying time 3.0h, complete drying time 26h.

[0067] Example 3

[0068] A high-strength, single-component polyurethane waterproof coating is prepared for a total volume of 100 kg. The specific weights of each component are as follows:

[0069] Polyether polyol-TDI-terminated NCO prepolymer 35.0kg, APDS 1.4kg, FDM 0.9kg, HBP-Si-NH2 1.0kg, MEI-K 2.5kg, compound filler 38.0kg, low-aromatic environmentally friendly heavy aromatic solvent S-150 6.5kg, bismuth neodecanoate 0.35kg, polyether-polyester graft-modified polysiloxane defoamer 0.7kg, compound antioxidant 1.2kg.

[0070] Preparation method (same as in Example 1):

[0071] (1) Add polyether polyol N220, APDS, FDM and compound filler to the reactor, start stirring, adjust the speed to 1000 r / min, raise the temperature to 118℃, and dehydrate for 2.5 h under vacuum of -0.098 MPa to obtain dehydrated mixture;

[0072] (2) Cool the dehydrated mixture obtained in step (1) to 82°C, add TDI-80, low aromatic environmentally friendly heavy aromatic solvent S-150 and polyether-polyester grafted modified polysiloxane defoamer, purge with nitrogen (nitrogen purging rate 1.2 L / min), adjust the stirring speed to 1500 r / min, and react at a constant temperature for 2 h to obtain silicon hybrid NCO polyurethane prepolymer;

[0073] (3) Add HBP-Si-NH2, bismuth neodecanoate and compound antioxidant to the silicon hybrid NCO polyurethane prepolymer obtained in step (2), adjust the stirring speed to 2000 r / min, and stir for 30 min under a vacuum of -0.098 MPa to ensure that the system is uniform and free of bubbles.

[0074] (4) Add MEI-K to the mixture obtained in step (3), continue vacuum stirring for 20 minutes, then stop stirring, cool down to below 40°C under nitrogen protection, discharge the material, seal and package it to obtain the high-strength single-component polyurethane waterproof coating.

[0075] Performance test results: tensile strength 7.5MPa, elongation at break 570%, no cracks after bending at -30℃, no sagging on 2mm vertical surfaces, water contact angle 112°, adhesion strength on damp substrate 1.8MPa, no delamination or blistering after 240h water immersion, tensile strength retention rate 97%, sealed storage period 17 months, no blistering or pinholes during construction at 20%~90% relative humidity, surface drying time 2.0h, and complete drying time 22h.

[0076] Comparative Example 1 (HBP-Si-NH2 missing)

[0077] A single-component polyurethane waterproof coating is prepared in a total volume of 100 kg. The specific weights of each component are the same as in Example 1, except that HBP-Si-NH2 is not added. Specifically, the components are: 32.8 kg of polyether polyol-TDI-terminated NCO prepolymer, 1.2 kg of APDS, 0.8 kg of FDM, 2.3 kg of MEI-K, 39.2 kg of compound filler, 6.8 kg of low-aromatic environmentally friendly heavy aromatic solvent S-150, 0.32 kg of bismuth neodecanoate, 0.58 kg of polyether-polyester grafted modified polysiloxane defoamer, and 1.0 kg of compound antioxidant.

[0078] The preparation method is the same as in Example 1 (without adding HBP-Si-NH2).

[0079] Performance test results: tensile strength 6.4MPa, elongation at break 510%, low temperature bending crack at -30℃, slight sagging on 2mm vertical surfaces, water contact angle 102°, adhesion strength on damp substrate 1.4MPa, slight debonding and no blistering after 240h water immersion, tensile strength retention rate 88%, sealed storage period 10 months, a small number of pinholes appeared in high humidity environment during construction at 20%~90% relative humidity, surface drying time 2.8h, and complete drying time 28h.

[0080] Comparative Example 2 (Missing MEI-K)

[0081] A single-component polyurethane waterproof coating is prepared in a total volume of 100 kg. The specific weights of each component are the same as in Example 1, except that MEI-K is replaced with ordinary methyl ethyl ketone imine (amine value 250~270 mgKOH / g, hydrolysis rate 0.01~0.02 mol / (L·h)). The components are as follows: 32.0 kg of polyether polyol-TDI-terminated NCO prepolymer, 1.2 kg of APDS, 0.8 kg of FDM, 0.8 kg of HBP-Si-NH2, 2.3 kg of ordinary methyl ethyl ketone imine, 39.2 kg of compound filler, 6.8 kg of low-aromatic environmentally friendly heavy aromatic solvent S-150, 0.32 kg of bismuth neodecanoate, 0.58 kg of polyether-polyester graft-modified polysiloxane defoamer, and 1.0 kg of compound antioxidant.

[0082] The preparation method is the same as in Example 1 (MEI-K is replaced with ordinary methyl ethyl ketone imine).

[0083] Performance test results: tensile strength 6.6MPa, elongation at break 520%, slight cracking when bent at -30℃, no obvious sagging on 2mm vertical surfaces, water contact angle 103°, adhesion strength to damp substrate 1.5MPa, no debonding or blistering after 240h water immersion, tensile strength retention rate 90%, sealed storage period 11 months, surface drying is too slow in low humidity environment and a small number of bubbles appear in high humidity environment when applied under 20%~90% relative humidity, surface drying time 2.8h, complete drying time 28h.

[0084] Comparative Example 3 (Missing APDS)

[0085] A single-component polyurethane waterproof coating is prepared in a total volume of 100 kg. The specific weights of each component are the same as in Example 1, except that APDS is not added. Specifically, the components are: 33.2 kg of polyether polyol-TDI-terminated NCO prepolymer, 0.8 kg of FDM, 0.8 kg of HBP-Si-NH2, 2.3 kg of MEI-K, 39.2 kg of compound filler, 6.8 kg of low-aromatic environmentally friendly heavy aromatic solvent S-150, 0.32 kg of bismuth neodecanoate, 0.58 kg of polyether-polyester grafted modified polysiloxane defoamer, and 1.0 kg of compound antioxidant.

[0086] The preparation method is the same as in Example 1 (without adding APDS).

[0087] Performance test results: tensile strength 6.2MPa, elongation at break 490%, low temperature bending cracking at -30℃, obvious sagging on 2mm vertical surfaces, water contact angle 98°, adhesion strength on damp substrate 1.3MPa, severe debonding and no blistering after 240h water immersion, tensile strength retention rate 85%, sealed storage period 9 months, blistering and sagging problems of varying degrees are present during construction at relative humidity of 20%~90%, surface drying time 3.2h, and complete drying time 30h.

[0088] Comparative Example 4 (Missing FDM)

[0089] A single-component polyurethane waterproof coating is prepared in a total volume of 100 kg. The specific weights of each component are the same as in Example 1, except that FDM is not added. Specifically, the components are: 32.8 kg of polyether polyol-TDI-terminated NCO prepolymer, 1.2 kg of APDS, 0.8 kg of HBP-Si-NH2, 2.3 kg of MEI-K, 39.2 kg of compound filler, 6.8 kg of low-aromatic environmentally friendly heavy aromatic solvent S-150, 0.32 kg of bismuth neodecanoate, 0.58 kg of polyether-polyester graft-modified polysiloxane defoamer, and 1.0 kg of compound antioxidant.

[0090] The preparation method is the same as in Example 1 (without adding FDM).

[0091] Performance test results: tensile strength 5.8MPa, elongation at break 580%, no cracks after bending at -30℃, no sagging on a 2mm vertical surface, water contact angle 109°, adhesion strength to damp substrate 1.4MPa, no delamination or blistering after 240h water immersion, tensile strength retention rate 94%, sealed storage period 14 months, no blistering or pinholes during construction at 20%~90% relative humidity, surface drying time 2.6h, complete drying time 25h.

[0092] IV. Summary Table of Performance Test Results for Examples and Comparative Examples

[0093] Group Tensile strength (MPa) Elongation at break (%) -30℃ low temperature bending Example 1 7.3 560 No cracks Example 2 7.2 550 No cracks Example 3 7.5 570 No cracks Comparative Example 1 6.4 510 cracking Comparative Example 2 6.6 520 Slight cracks Comparative Example 3 6.2 490 cracking Comparative Example 4 5.8 580 No cracks

[0094] Based on the summary table of performance test results above, and comparing Examples 1-3 with Comparative Examples 1-4, it can be seen that the quaternary components APDS, FDM, HBP-Si-NH2, and MEI-K are all indispensable. Only through the synergistic effects of rigid-flexible complementarity, gradient curing, and structural regulation can the excellent properties defined in the claims be achieved. The absence of any one component will disrupt the synergistic effect of the system, leading to problems such as substandard mechanical properties, decreased construction adaptability, shortened storage period, and deteriorated water resistance: The absence of HBP-Si-NH2 results in insufficient crosslinking density, significantly reduced low-temperature crack resistance, and a shortened storage period; the absence of MEI-K prevents gradient curing, resulting in poor construction adaptability; the absence of APDS prevents the construction of a rigid-flexible complementary framework, significantly reducing flexibility and hydrophobicity; and the absence of FDM results in insufficient strength, failing to achieve a balance between rigidity and flexibility.

[0095] In this application, APDS, FDM, HBP-Si-NH2, and MEI-K are compounded in a defined ratio to form a stable linear-hyperbranched interpenetrating silicon-nitrogen crosslinking network, achieving three-stage gradient curing. This ultimately gives the waterproof coating comprehensive advantages such as high strength, high toughness, low-temperature crack resistance, full humidity application, thick coating without bubbles, and stable storage. The performance of Examples 1-3 meets or exceeds the standards defined in the claims, fully demonstrating the outstanding substantive features and significant progress of the quaternary synergistic system of this invention, and further verifying the inventiveness and practicality of the technical solution of this invention.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high-strength single-component polyurethane waterproof coating, characterized in that, The product comprises the following components by weight percentage: 32%~35% polyether polyol-toluene diisocyanate-terminated NCO prepolymer, 1.0%~1.4% bis(3-aminopropyl)disiloxane, 2.0%~2.5% latent curing agent; 0.7%~0.9% 2,5-furandimethyl alcohol; 38%~40% compound filler; 6.5%~7.5% low-aromatic environmentally friendly heavy aromatic solvent S-150; 0.25%~0.35% organic bismuth catalyst; 0.5%~0.7% polyether-polyester grafted modified polysiloxane defoamer; and 1.0%~1.2% compound antioxidant. The polyether polyol-toluene diisocyanate-terminated NCO prepolymer is prepared by reacting polyether polyol N220 and TDI-80 at a mass ratio of 1:0.35~0.40, and the mass fraction of the NCO in the prepolymer is 6.0%~8.0%.

2. The high-strength single-component polyurethane waterproof coating according to claim 1, characterized in that: It also includes 0.6% to 1.0% of terminal amino hyperbranched polysiloxane, wherein the degree of branching of the terminal amino hyperbranched polysiloxane is 2.5 to 3.0, the number average molecular weight is 1500 to 2500, and the terminal amino content is 0.8 to 1.2 mmol / g.

3. The high-strength single-component polyurethane waterproof coating according to claim 1, characterized in that: The latent curing agent is methyl ethyl ketone imine modified isophorone diamine ketone imine, wherein the amine value of the methyl ethyl ketone imine modified isophorone diamine ketone imine is 280~320 mgKOH / g and the hydrolysis rate is 0.02~0.03 mol / (L·h).

4. The high-strength single-component polyurethane waterproof coating according to claim 1, characterized in that: The compound filler is composed of heavy calcium carbonate, calcined kaolin and carbon black in a mass ratio of 3:1:0.05; the compound antioxidant is composed of hindered phenolic antioxidant 1010 and phosphite antioxidant 168 in a mass ratio of 1:

1.

5. The high-strength single-component polyurethane waterproof coating according to claim 1, characterized in that: The organic bismuth catalyst is bismuth neodecanoate.

6. A method for preparing a high-strength single-component polyurethane waterproof coating as described in any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Add polyether polyol N220, bis(3-aminopropyl)disiloxane, 2,5-furandimethylethanol and compound filler into the reactor, start stirring, adjust the speed to 800~1000r / min, raise the temperature to 115~118℃, and dehydrate under vacuum conditions of -0.096~-0.098MPa for 2.5h to obtain a dehydrated mixture; (2) Cool the dehydrated mixture obtained in step (1) to 78~82℃, add TDI-80, low aromatic environmentally friendly heavy aromatic solvent S-150 and polyether-polyester grafted modified polysiloxane defoamer, purge with nitrogen for protection, adjust the stirring speed to 1200~1500r / min, and react at a constant temperature for 2h to obtain silicon hybrid NCO polyurethane prepolymer; (3) Add amino-terminated hyperbranched polysiloxane, organic bismuth catalyst and compound antioxidant to the silicon hybrid NCO polyurethane prepolymer obtained in step (2), adjust the stirring speed to 2000 r / min, stir under vacuum for 30 min to ensure that the system is uniform and free of bubbles. (4) Add methyl ethyl ketone imine modified isophorone diamine ketone imine to the mixture obtained in step (3), continue vacuum stirring for 20 minutes, then stop stirring, cool down to below 40°C under nitrogen protection, discharge the material, seal and package it to obtain the high-strength environmentally friendly single-component polyurethane waterproof coating.

7. The preparation method according to claim 6, characterized in that: In step (2), the nitrogen gas is introduced at a rate of 0.8~1.2 L / min, and the temperature fluctuation of the system is controlled to not exceed ±2℃ during the reaction.

8. The preparation method according to claim 7, characterized in that, In step (3), the vacuum level is maintained at -0.096 to -0.098 MPa. The system state is observed during stirring to ensure that no bubbles are generated.

9. The high-strength single-component polyurethane waterproof coating according to claim 1, characterized in that: The waterproof coating has a water contact angle ≥108°, a wet substrate adhesion strength ≥1.6MPa, and is resistant to water immersion for 240 hours without delamination or blistering.