Low voc high performance one-component polyurethane waterproof coating and preparation method thereof

Abstract

This invention relates to a low-VOC, high-performance, single-component polyurethane waterproof coating and its preparation method, belonging to the field of coating technology. The low-VOC, high-performance, single-component polyurethane waterproof coating of this invention comprises polyether diol, polyether triol, dispersant, colorant, fluorosiloxane-modified needle-like wollastonite, unmodified powder, isocyanate, catalyst, latent curing agent, defoamer, high-boiling-point solvent, and polymerization inhibitor. The single-component polyurethane waterproof coating prepared by this invention features low VOC, low odor, and solvent-free characteristics, with a plasticizer content far lower than similar products. It exhibits excellent mechanical properties, good workability, water resistance, corrosion resistance, and aging resistance, and its surface is hydrophobic, making it difficult for moisture to adhere, thus providing excellent waterproof performance.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a low-VOC, high-performance, single-component polyurethane waterproof coating and its preparation method. Background Technology

[0002] Single-component polyurethane waterproof coatings are increasingly widely used in the construction industry. Firstly, they offer superior performance, providing better flexibility and elasticity than most current water-based coatings. Secondly, they can adapt to complex application scenarios, such as roofs, balconies, and bathrooms, meeting various engineering construction needs. Compared to two-component polyurethane waterproof coatings, single-component polyurethane requires no mixing, making application more convenient. In the future roof repair market, single-component polyurethane will become one of the mainstream basic product solutions. Currently, polyurethane products account for a large proportion of the waterproof coating market and have broad development prospects.

[0003] Currently, the mainstream products on the market are single-component polyurethane waterproofing products that conform to the GB / T 19250-2013 national standard type II. Their tensile strength is 2–3 MPa, and VOC content is 100–200 g / L. They are inexpensive and occupy a large market share. However, their main problems are lower performance, strong odor during construction, and easy dust accumulation on the surface.

[0004] With the development of technology and the progress of the times, the construction industry has increased its performance requirements for waterproofing products and is paying more and more attention to their environmental friendliness. Currently, there are relatively few high-performance waterproofing products on the market. Their environmental friendliness is mainly achieved by replacing traditional low-boiling-point solvents with high-boiling-point plasticizers. To control the viscosity of the system, the addition amount of high-boiling-point plasticizers is usually above 10%, such as the 15% to 30% in patent publications CN114437621A and CN104194609A. Adding low-viscosity high-boiling-point plasticizers can reduce the VOCs in the system. However, the large amount of plasticizer added will affect the durability of the coating film performance. As the plasticizer slowly migrates out, the tensile properties of the coating film will gradually weaken. The mainstream solution for high performance is to introduce urea bonds to improve the system performance, as seen in patent publications CN107474713A and CN106497371A, which improve system performance by introducing urea bonds with stronger binding forces. CN202310180045.0 discloses a high-performance single-component polyurethane waterproof coating and its preparation method. It improves the system performance by introducing quaternary ammonium salt to modify layered silicate. However, this requires peeling the silicate into a sheet structure, which is a relatively complex process. In addition, the residual quaternary ammonium salt has a certain catalytic effect on isocyanate, which has a negative impact on storage stability.

[0005] In conclusion, there is a market need for a high-performance, low-VOC, single-component polyurethane waterproof coating to meet the needs of the high-end market. Summary of the Invention

[0006] This invention provides a low-VOC, high-performance single-component polyurethane waterproof coating and its preparation method. The single-component polyurethane waterproof coating prepared by this invention has the characteristics of low VOC, low odor, and no solvent, and the content of plasticizer is much lower than that of similar products. It has excellent mechanical properties, good workability, water resistance, corrosion resistance, and aging resistance, and the surface is hydrophobic, so water does not easily adhere to its surface, thus exhibiting good waterproof performance.

[0007] To solve the above problems, the present invention is achieved through the following technical solution:

[0008] The first objective of this invention is:

[0009] A low-VOC, high-performance, one-component polyurethane waterproof coating is provided, comprising the following components by weight percentage:

[0010] Polyether diol 20-40%, polyether triol 1-4%, dispersant 0.1-0.5%, colorant 0.1-0.3%, fluorosiloxane-modified needle-like wollastonite 20%-40%, unmodified powder 10-60%, isocyanate 4-9%, catalyst 0.05-0.2%, latent curing agent 0.2-0.9%, defoamer 0.1-0.5%, high-boiling-point solvent 5-8%, polymerization inhibitor 0.01-0.1%; the sum of all components is 100%.

[0011] The fluorosiloxane-modified needle-shaped wollastonite is prepared by the following method:

[0012] The fluorosiloxane modifier was added to a mixed solution of ethanol and water, and triethylamine was added to adjust the pH to 9-10. Needle-shaped wollastonite was added while stirring, and the reaction was carried out at 40-70℃ for 3 hours. The resulting product was then filtered, washed, and dried to obtain the fluorosiloxane-modified needle-shaped wollastonite.

[0013] The mass ratio of ethanol to water in the ethanol-water mixture is 1.2:1.

[0014] The mass ratio of the fluorosiloxane modifier to the acicular wollastonite is 1:30 to 300.

[0015] The low-VOC, high-performance, single-component polyurethane waterproof coating of the present invention is further optimized as follows:

[0016] The polyether diol has a molecular weight between 1000 and 2000, and the polyether triol has a molecular weight between 3000 and 4000, wherein the mass ratio of polyether diol to polyether triol is 9 to 20.

[0017] The low-VOC, high-performance, single-component polyurethane waterproof coating of the present invention is further optimized as follows:

[0018] The fluorosiloxane-modified acicular wollastonite has an aspect ratio greater than 10:1, and its acicular structure can effectively improve the tensile strength and tear strength of the coating.

[0019] The low-VOC, high-performance, single-component polyurethane waterproof coating of the present invention is further optimized as follows:

[0020] The fluorosiloxane modifier is one or a combination of several of 3,3,3-trifluoropropylmethyldimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, and tridecafluorooctyltrimethoxysilane.

[0021] The low-VOC, high-performance, single-component polyurethane waterproof coating of the present invention is further optimized as follows:

[0022] It includes one or a combination of the following technical features:

[0023] The unmodified powder is one or a combination of calcined kaolin, calcite, and talc.

[0024] The isocyanate is one or a combination of several of toluene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate, and the molar ratio of its NCO group to the OH group in the polyol resin is between 2.00 and 2.20.

[0025] The catalyst is one or a combination of organometallic polyurethane catalysts and tertiary amine polyurethane catalysts; preferably, it is one or a combination of dibutyltin dilaurate and stannous octoate.

[0026] The latent curing agent is one or a combination of imine-type latent curing agents and oxazolidine-type latent curing agents;

[0027] The high-boiling-point solvents mentioned are: one or a combination of several of the following: acetyl tributyl citrate, tributyl citrate, diisononyl phthalate, diisononyl cyclohexane-1,2-dicarboxylic acid, and dioctyl terephthalate.

[0028] The polymerization inhibitor is one or a combination of several of benzoic acid, phosphoric acid, citric acid, and benzoyl chloride.

[0029] The second objective of this invention is:

[0030] A method for preparing the low-VOC, high-performance, single-component polyurethane waterproof coating described above (including optimized solutions) is provided, comprising the following preparation steps:

[0031] S1. Add polyether diol, polyether triol, and dispersant to the reactor and stir at low speed for 10 minutes;

[0032] S2. Add color powder, fluorosiloxane-modified needle-shaped wollastonite, and unmodified powder, and stir at high speed for 30 minutes;

[0033] S3. Heat to 110-120℃, and simultaneously evacuate to a pressure below -0.09MPa, stir at medium speed, and maintain for 3 hours;

[0034] S4. Turn off the vacuum, cool to 80-85℃, add isocyanate and some high-boiling-point solvent, stir at medium speed, and react for 3 hours.

[0035] S5. Add catalyst and react for 1 hour;

[0036] S6. Cool to 75-78℃, add latent curing agent and react for 1 hour, then turn off the heating;

[0037] S7. Cool the temperature to below 60°C, add the remaining high-boiling-point solvent, defoamer, and polymerization inhibitor, evacuate to below 0.09 MPa, and stir at low speed for 20 minutes to obtain the low-VOC high-performance single-component polyurethane waterproof coating.

[0038] The low-VOC, high-performance, single-component polyurethane waterproof coating prepared by this invention exhibits excellent mechanical properties, with a tensile strength exceeding 6 MPa, a tear strength greater than 30 N / mm, and an elongation at break greater than 500%, meeting the requirements of GB / T 19250-2013 Type II. This is mainly attributed to the addition of fluorosiloxane-modified acicular wollastonite. The unique needle-like structure of acicular wollastonite, similar to reinforcing fillers such as fibrous talc and glass fiber, significantly enhances the mechanical properties of the system. This invention modifies the surface of the acicular wollastonite, attaching fluorosiloxane-containing alkyl groups to its surface. This allows the acicular wollastonite to disperse better in organic matter, promoting microphase separation within the coating. Furthermore, the modified wollastonite surface possesses more active groups, enabling it to react with NCO-terminated resins to form crosslinks, increasing the crosslinking density and significantly improving the system's strength.

[0039] The low-VOC, high-performance single-component polyurethane waterproof coating prepared by this invention is characterized by its low VOC content and significantly lower high-boiling-point plasticizer content compared to similar products. This is due to the unique resin and powder composition of this invention. Traditional single-component polyurethane waterproof coatings often use a combination of 2000 molecular weight polyether diol and 5000 molecular weight polyether triol, with a mass ratio of 2 to 8. In traditional solutions, the triol resin content is relatively high. Triol resin can increase the crosslinking density and strength of the system; its large molecular weight provides three crosslinking points, and the higher the triol resin content, the larger the prepolymer molecular weight and the higher the system viscosity. The single-component polyurethane waterproof coating of this invention uses a resin with a relatively low molecular weight. The addition of modified wollastonite increases the crosslinking density, eliminating the need for excessive triol resin for crosslinking. The triol resin content is extremely low, resulting in a smaller prepolymer molecular weight and a viscosity far lower than traditional solutions. After modification with fluorosiloxanes, the surface wettability of wollastonite is improved, allowing for better dispersion in the coating system and effectively reducing the coating viscosity. Due to the combination of resin and powder, this invention only requires a small amount of plasticizer to reduce the viscosity to below 10,000 cp. The plasticizer content is about half that of similar products. Relatively speaking, the plasticizer is less likely to migrate out, and the mechanical properties are more stable.

[0040] The low-VOC, high-performance, single-component polyurethane waterproof coating prepared by this invention exhibits hydrophobicity on the cured film surface. The fluorosiloxane-modified needle-like wollastonite surface possesses numerous F groups, which significantly reduce the surface energy of the coating, resulting in a hydrophobic film surface. This hydrophobicity endows the material with higher water resistance, while the low surface energy also makes the coating surface less prone to dust accumulation.

[0041] Thick coats of single-component polyurethane waterproof coatings typically require multiple applications. Traditional single-component polyurethane coatings are prone to dust accumulation on their surface. During the second coat application, dust remains in the system, causing defects in the paint film. This invention effectively solves this problem. Attached Figure Description

[0042] Figure 1 This invention relates to a fluorosiloxane modifier (left figure) and fluorosiloxane-modified needle-shaped wollastonite (right figure). Detailed Implementation

[0043] To make the application, technical solution, and advantages of this invention clearer, the invention is described in detail with reference to specific embodiments. It should be understood that the embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Any simple improvements to the preparation method of this invention based on the inventive concept fall within the scope of protection of this invention.

[0044] Example 1

[0045] A method for preparing a low-VOC, high-performance, single-component polyurethane waterproof coating, comprising the following preparation steps:

[0046] (I) Preparation of fluorosiloxane-modified needle-shaped wollastonite:

[0047] The fluorosiloxane-modified needle-shaped wollastonite is prepared by the following method:

[0048] The fluorosiloxane modifier was added to a mixed solution of ethanol and water, and triethylamine was added to adjust the pH to 9-10. Needle-shaped wollastonite was added while stirring, and the reaction was carried out at 40-70℃ for 3 hours. The resulting product was then filtered, washed, and dried to obtain the fluorosiloxane-modified needle-shaped wollastonite.

[0049] The mass ratio of ethanol to water in the ethanol-water mixture is 1.2:1.

[0050] The mass ratio of the fluorosiloxane modifier to the acicular wollastonite is 1:200.

[0051] The fluorosiloxane modifier mentioned above is tridecafluorooctyltrimethoxysilane FS1310 produced by Fuzhou Taipuda New Material Co., Ltd.

[0052] The acicular wollastonite mentioned above is acicular wollastonite powder produced by Jiangxi Kete Fine Powder Co., Ltd.

[0053] (II) Preparation of low-VOC, high-performance single-component polyurethane waterproof coatings:

[0054] The low-VOC, high-performance, single-component polyurethane waterproof coating is prepared through the following steps (by weight):

[0055] S1. Add polyether diol, polyether triol, and dispersant to the reactor and stir at low speed for 10 minutes;

[0056] S2. Add color powder, fluorosiloxane-modified needle-shaped wollastonite, and unmodified powder, and stir at high speed for 30 minutes;

[0057] S3. Heat to 110-120℃, and simultaneously evacuate to a pressure below -0.09MPa, stir at medium speed, and maintain for 3 hours;

[0058] S4. Turn off the vacuum, cool to 80-85℃, add isocyanate and some high-boiling-point solvent, stir at medium speed, and react for 3 hours.

[0059] S5. Add catalyst and react for 1 hour;

[0060] S6. Cool to 75-78℃, add latent curing agent and react for 1 hour, then turn off the heating;

[0061] S7. Cool the temperature to below 60°C, add the remaining high-boiling-point solvent, defoamer, and polymerization inhibitor, evacuate to below 0.09 MPa, and stir at low speed for 20 minutes to obtain the low-VOC high-performance single-component polyurethane waterproof coating.

[0062] The polyether diol mentioned above is VORANOL 2000LM polyether polyol produced by Dow Chemical.

[0063] The polyether triol mentioned above is VORANOL 3003N polyether polyol produced by Dow Chemical.

[0064] The unmodified powder mentioned above is calcite;

[0065] The isocyanate mentioned therein is TDI-80;

[0066] The catalyst mentioned above is dibutyltin dilaurate;

[0067] The high-boiling-point solvent mentioned above is diisononyl phthalate;

[0068] The latent curing agent mentioned above is SLD-910 produced by Suzhou Sailide Chemical Co., Ltd.

[0069] The polymerization inhibitor mentioned therein is benzoic acid.

[0070] Example 2

[0071] A method for preparing a low-VOC, high-performance, single-component polyurethane waterproof coating, comprising the following preparation steps:

[0072] (I) Preparation of fluorosiloxane-modified needle-shaped wollastonite:

[0073] The fluorosiloxane-modified needle-shaped wollastonite is prepared by the following method:

[0074] The fluorosiloxane modifier was added to a mixed solution of ethanol and water, and triethylamine was added to adjust the pH to 9-10. Needle-shaped wollastonite was added while stirring, and the reaction was carried out at 40-70℃ for 3 hours. The resulting product was then filtered, washed, and dried to obtain the fluorosiloxane-modified needle-shaped wollastonite.

[0075] The mass ratio of ethanol to water in the ethanol-water mixture is 1.2:1.

[0076] The mass ratio of the fluorosiloxane modifier to the acicular wollastonite is 1:300.

[0077] The fluorosiloxane modifier mentioned above is 3,3,3-trifluoropropylmethyldimethoxysilane produced by Hubei Kefule Materials Technology Co., Ltd.

[0078] The needle-shaped wollastonite mentioned above is needle-shaped wollastonite powder produced by Xinyu Juyuan Wollastonite Co., Ltd.

[0079] (II) Preparation of low-VOC, high-performance single-component polyurethane waterproof coatings:

[0080] The low-VOC, high-performance, single-component polyurethane waterproof coating is prepared through the following steps (by weight):

[0081] S1. Add polyether diol, polyether triol, and dispersant to the reactor and stir at low speed for 10 minutes;

[0082] S2. Add color powder, fluorosiloxane-modified needle-shaped wollastonite, and unmodified powder, and stir at high speed for 30 minutes;

[0083] S3. Heat to 110-120℃, and simultaneously evacuate to a pressure below -0.09MPa, stir at medium speed, and maintain for 3 hours;

[0084] S4. Turn off the vacuum, cool to 80-85℃, add isocyanate and some high-boiling-point solvent, stir at medium speed, and react for 3 hours.

[0085] S5. Add catalyst and react for 1 hour;

[0086] S6. Cool to 75-78℃, add latent curing agent and react for 1 hour, then turn off the heating;

[0087] S7. Cool the temperature to below 60°C, add the remaining high-boiling-point solvent, defoamer, and polymerization inhibitor, evacuate to below 0.09 MPa, and stir at low speed for 20 minutes to obtain the low-VOC high-performance single-component polyurethane waterproof coating.

[0088] The polyether diol mentioned above is DL-2000D produced by Shandong Lanxing Dongda Co., Ltd.

[0089] The polyether triol mentioned above is DL-4000D produced by Shandong Lanxing Dongda Co., Ltd.

[0090] The unmodified powder mentioned above is talc powder;

[0091] The isocyanate mentioned therein is MDI-50;

[0092] The catalyst mentioned above is dibutyltin dilaurate;

[0093] The high-boiling-point solvent mentioned above is acetyl tributyl citrate (ATBC).

[0094] The latent curing agent mentioned above is ALT-401 produced by Changde Elite New Material Technology Co., Ltd.

[0095] The polymerization inhibitor mentioned therein is benzoyl chloride.

[0096] Comparative Example 1

[0097] The preparation of the fluorosiloxane-modified needle-shaped wollastonite in Comparative Example 1 was the same as in Example 1.

[0098] In the preparation steps of the single-component polyurethane waterproof coating in Comparative Example 1, the amount of fluorosiloxane-modified needle-shaped wollastonite added was 46.44 parts, and the amount of unmodified powder added was 0 parts; the rest was consistent with Example 1.

[0099] Comparative Example A

[0100] Add polyether diol and polyether triol to the reactor, and simultaneously evacuate to a pressure below -0.09 MPa. Stir at medium speed and maintain for 3 hours.

[0101] Turn off the vacuum, cool down to 80-85℃, add isocyanate, react for 3 hours, add catalyst, and react for 1 hour.

[0102] When the temperature is lowered to below 60°C, a vacuum is drawn to below 0.09 MPa for 20 minutes to obtain the pure polymer system product.

[0103] The polyether diol mentioned above is VORANOL 2000LM polyether polyol produced by Dow Chemical, with a molecular weight of 2000.

[0104] The polyether triol mentioned above is VORANOL 3003N polyether polyol produced by Dow Chemical, with a molecular weight of 3000;

[0105] The isocyanate mentioned therein is TDI-80;

[0106] The catalyst mentioned above is dibutyltin dilaurate.

[0107] Comparative Example 2

[0108] Comparative Example 2 does not include step (I) of the preparation of fluorosiloxane-modified acicular wollastonite in Example 1;

[0109] The fluorosiloxane-modified acicular wollastonite in Example 1 was replaced with unmodified acicular wollastonite;

[0110] The rest remains the same as in Example 1.

[0111] Comparative Example 3

[0112] In Comparative Example 3, the acicular wollastonite in step (I) of the preparation of fluorosiloxane-modified acicular wollastonite in Example 1 was replaced with ordinary wollastonite with a low aspect ratio, while the rest remained the same as in Example 1.

[0113] The preparation steps (II) of the single-component polyurethane waterproof coating in Comparative Example 3 are consistent with those in Example 1.

[0114] Comparative Example 4

[0115] The ratio of polyether diol to polyether triol in Example 1 was changed from 36:3 to 32:7, while the rest remained the same as in Example 1.

[0116] Comparative Example 5

[0117] Comparative Example 5 follows the same preparation steps (i) as in Example 1 for fluorosiloxane-modified acicular wollastonite.

[0118] The preparation steps (II) of the single-component polyurethane waterproof coating in Comparative Example 5 differ from those in Example 1 in the following ways:

[0119] In Example 1, the polyether diol was replaced with polyether polyol 220 and the polyether triol was replaced with polyether polyol 330N. In order to keep the R value consistent with that in Example 1, the amount of toluene diisocyanate (TDI) added was changed to 6.9. The remaining steps were the same as in Example 1.

[0120] Comparative Example B

[0121] Add polyether diol and polyether triol to the reactor, and simultaneously evacuate to a pressure below -0.09 MPa. Stir at medium speed and maintain for 3 hours.

[0122] Turn off the vacuum, cool down to 80-85℃, add isocyanate, react for 3 hours, add catalyst, and react for 1 hour.

[0123] When the temperature is lowered to below 60°C, a vacuum is drawn to below 0.09 MPa for 20 minutes to obtain the pure polymer system product.

[0124] The polyether diol mentioned above is polyether polyol 220;

[0125] The polyether triol mentioned above is polyether polyol 330N;

[0126] The isocyanate mentioned therein is TDI-80;

[0127] The catalyst mentioned above is dibutyltin dilaurate.

[0128] Comparative Example 6

[0129] Comparative Example 6 is a GB / T 19250-2013 national standard type II single-component polyurethane waterproof coating with a high market share.

[0130] Table 1. Raw material composition (parts by weight) of the embodiments and comparative examples of the present invention.

[0131]

[0132]

[0133] Performance testing:

[0134] The physical properties of the materials in the examples and comparative examples were tested according to GB / T 19250-2013. The viscosity was measured using a Brookfield RV viscometer, and the water contact angle was measured using a Shengding Precision SDC-100 contact angle measuring instrument. The test results are shown in Table 2.

[0135] Table 2 Test Results

[0136]

[0137] As can be seen from Examples 1 and 2, the single-component polyurethane waterproof coating prepared by the present invention has the characteristics of low viscosity, good mechanical properties, and hydrophobic surface.

[0138] As can be seen from Example 1 and Comparative Example 1, increasing the amount of fluorosiloxane-modified acicular wollastonite can improve the tensile strength and surface hydrophobicity of the system. Compared with Example 1, the elongation at break and tear strength of Comparative Example 1 decreased significantly, possibly because the excessive amount of fluorosiloxane-modified acicular wollastonite led to an excessively high crosslinking density in the system, thus reducing flexibility. A combination of modified and unmodified powders can achieve better overall mechanical properties.

[0139] As can be seen from Example 1 and Comparative Example 2, fluorosiloxane modification of acicular wollastonite can significantly improve the mechanical properties of the system. The tensile strength, elongation at break, and tear strength are all significantly improved after modification. This is because the modified acicular wollastonite can crosslink with the polymer, increasing the crosslinking density of the system. At the same time, since the surface of the acicular wollastonite has been modified, it is easier for it to be wetted by the polymer, resulting in a significant decrease in the viscosity of the system.

[0140] As can be seen from Example 1 and Comparative Example 3, compared with ordinary wollastonite with a low aspect ratio, acicular wollastonite can significantly improve the mechanical properties of the system, especially the tear strength. This is due to the special acicular structure of acicular wollastonite, which, like glass fibers, is distributed in the coating system and plays a reinforcing role.

[0141] As can be seen from Example 1 and Comparative Example 4, the content of polyether triol after modifying acicular wollastonite with fluorosiloxane should not be too high. In traditional one-component polyurethanes, the mass ratio of polyether diol to polyether triol is between 2 and 8. Triol resin can increase the crosslinking density of the system and increase its strength. After adding fluorosiloxane-modified acicular wollastonite, the crosslinking density of the system is already very high, and no more polyether triol is needed to provide crosslinking density. In Comparative Example 4, due to excessive crosslinking density, the elongation at break is close to the national standard limit, and its tear strength also decreases significantly.

[0142] Comparative Examples A and B are both pure polymer components without powder. The performance comparison shows that using low molecular weight polyether triols significantly reduces the viscosity of the prepolymer and also significantly improves its mechanical properties. Combining Example 1 and Comparative Example 5, it can be seen that the viscosity of Example 1 is lower than that of Comparative Example 5, and its mechanical strength is superior to that of Comparative Example 5. Its test results are consistent with those of pure polymers.

[0143] As can be seen from Example 1 and Comparative Example 6, the high-performance single-component polyurethane waterproof material prepared by this invention has the characteristics of low VOC, good mechanical properties, high tear strength, high surface hydrophobicity, and stronger water resistance compared with traditional materials on the market. This invention, through the selection of resin molecular weight, the unique ratio of polyether diol to polyether triol, and the addition of fluorosiloxane-modified needle-like wollastonite, endows this product with unique and excellent comprehensive properties, providing a new high-performance product for the high-end waterproof market.

[0144] In summary, the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any changes, modifications, and evolutions made by those skilled in the art without departing from the scope of the present invention based on the disclosed technical content shall be considered equivalent embodiments of the present invention. Furthermore, any changes, modifications, and evolutions made to the above embodiments based on the essential technology of the present invention shall still fall within the protection scope of the present invention.

[0145] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0146] Experimental methods not specified in this invention are generally performed under conventional conditions or as recommended by the manufacturer.

[0147] Unless otherwise stated, the various optimized technical solutions in this invention can be combined with each other.

[0148] Unless otherwise stated, percentages and parts are weight percentages and weight parts.

[0149] Experimental methods not specified in the instructions and examples are generally performed under standard conditions or as recommended by the manufacturer.

[0150] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as are familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be used in the methods of this invention.

Claims

1. A low-VOC, high-performance, single-component polyurethane waterproof coating, characterized in that: It comprises the following components by weight percentage: Polyether diol 20-40%, polyether triol 1-4%, dispersant 0.1-0.5%, colorant 0.1-0.3%, fluorosiloxane-modified needle-like wollastonite 20-40%, unmodified powder 10-60%, isocyanate 4-9%, catalyst 0.05-0.2%, latent curing agent 0.2-0.9%, defoamer 0.1-0.5%, high-boiling-point solvent 5-8%, polymerization inhibitor 0.01-0.1%; the sum of all components is 100%. The molecular weight of the polyether diol is between 1000 and 2000, and the molecular weight of the polyether triol is between 3000 and 4000, wherein the mass ratio of the polyether diol to the polyether triol is 9 to 20. The fluorosiloxane-modified needle-shaped wollastonite was prepared by the following method: The fluorosiloxane modifier is added to a mixed solution of ethanol and water, and triethylamine is added to adjust the pH to 9-10. Needle-shaped wollastonite is added while stirring, and the reaction is carried out at 40-70℃ for 3 hours. The resulting product is then filtered, washed, and dried to obtain the fluorosiloxane-modified needle-shaped wollastonite. The fluorosiloxane modifier is one or a combination of several of 3,3,3-trifluoropropylmethyldimethoxysilane and 3,3,3-trifluoropropyltrimethoxysilane. The mass ratio of ethanol to water in the ethanol-water mixture is 1.2:

1. The mass ratio of the fluorosiloxane modifier to the acicular wollastonite is 1:30~300.

2. The low-VOC, high-performance, single-component polyurethane waterproof coating according to claim 1, characterized in that: The fluorosiloxane-modified acicular wollastonite has an aspect ratio greater than 10:

1.

3. The low-VOC, high-performance, single-component polyurethane waterproof coating according to claim 1, characterized in that: It includes one or a combination of the following technical features: The unmodified powder is one or a combination of calcined kaolin, calcite, and talc. The isocyanate is one or a combination of toluene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate, and the molar ratio of its NCO group to the OH group in the polyol resin is between 2.00 and 2.

20. The catalyst is one or a combination of organometallic polyurethane catalysts and tertiary amine polyurethane catalysts; The latent curing agent is one or a combination of imine-type latent curing agents and oxazolidine-type latent curing agents; The high-boiling-point solvent is one or a combination of several of the following: acetyl tributyl citrate, tributyl citrate, diisononyl phthalate, diisononyl cyclohexane-1,2-dicarboxylic acid, and dioctyl terephthalate. The polymerization inhibitor is one or a combination of several of benzoic acid, phosphoric acid, citric acid, and benzoyl chloride.

4. A method for preparing the low-VOC, high-performance, single-component polyurethane waterproof coating according to claim 1, characterized in that: It includes the following preparation steps: S1. Add polyether diol, polyether triol, and dispersant to the reactor and stir at low speed for 10 minutes; S2. Add color powder, fluorosiloxane-modified needle-shaped wollastonite, and unmodified powder, and stir at high speed for 30 minutes; S3. Heat to 110~120℃, and simultaneously evacuate to a pressure below -0.09MPa, stir at medium speed, and maintain for 3 hours; S4. Turn off the vacuum, cool to 80~85℃, add isocyanate and some high-boiling-point solvent, stir at medium speed, and react for 3 hours. S5. Add catalyst and react for 1 hour; S6. Cool to 75~78℃, add latent curing agent and react for 1 hour, then turn off the heating; S7. Cool the mixture to below 60°C, add the remaining high-boiling-point solvent, defoamer, and polymerization inhibitor, evacuate to below 0.09 MPa, and stir at low speed for 20 minutes to obtain the low-VOC high-performance single-component polyurethane waterproof coating.

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