Preparation method of polyurethane waterproof coating
By using the combination of potassium chlorhexidine, calcium carbonate and modified multi-wall carbon nanotubes in polyurethane waterproof coatings, a stable protective film is formed, which solves the problem of degradation in acidic environments, and achieves efficient waterproofing and mechanical performance maintenance.
Patent Information
- Application Number
- CN202510201527.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-24
- Publication Date
- 2025-05-30
AI Technical Summary
Existing polyurethane waterproof coatings are prone to react with acid in an acidic environment, causing the coating film to expand, blister and even burst, affecting waterproofing and mechanical properties.
A polyurethane waterproof coating was prepared by mixing titanium dioxide, silicon powder, calcium carbonate, potassium phenyladium and modified multi-wall carbon nanotubes in a specific proportion and stirring with polyurethane emulsion, styrene acrylic emulsion, dispersant and water. Potassium flavourate forms a stable bond with calcium carbonate and modified multi-wall carbon nanotubes to form a dense protective film to prevent acidic substances from erosion.
This coating can maintain good waterproofing and mechanical properties in an acidic environment, and the tensile strength retention rate is as high as 93.52%, which significantly improves the acid resistance of the coating film.
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Figure CN120059579A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of coatings, and particularly relates to a preparation method of a polyurethane waterproof coating. Background Art
[0002] Waterproof materials are widely used in the field of building material protection. After applying a waterproof coating to a building, a diaphragm can be formed by the coating to prevent corrosion caused by corrosive liquids such as rainwater and groundwater and moisture in the air from invading building materials, so as to extend the service life of building materials.
[0003] In existing polyurethane waterproof coatings, in order to increase the thickness and volume of the coating film and have certain hardness and wear resistance, calcium carbonate is added as a filler. However, there are some defects in adding calcium carbonate: calcium carbonate is a strong base weak acid salt and is prone to react with acids in an acidic environment. In a polyurethane waterproof coating, if the coating is exposed to an acidic environment (such as industrial waste gas, acid rain, etc.), calcium carbonate will react with the acid to generate carbon dioxide gas, causing the coating film to expand, blister or even rupture, seriously affecting the waterproof performance of the coating film and also leading to a decline in the mechanical properties of the coating film. Summary of the Invention
[0004] To solve the problems in the background art, the present invention provides a preparation method of a polyurethane waterproof coating to ensure good waterproof and mechanical properties of the coating film in an acidic environment.
[0005] To achieve the above object, the present invention provides the following technical solutions:
[0006] A preparation method of a polyurethane waterproof coating includes the following steps:
[0007] S1. By weight, mix 6 - 9 parts of titanium dioxide, 2 - 4 parts of silicon powder, 13 - 15 parts of calcium carbonate, 5 - 6 parts of fulvic acid potassium powder and 12 - 13 parts of modified multi-walled carbon nanotubes, and stir to obtain component A;
[0008] S2. Mix 75 - 80 parts of polyurethane emulsion, 18 - 22 parts of styrene-acrylic emulsion, 3 - 5 parts of dispersant and 13 - 16 parts of water, and stir to obtain component B;
[0009] S3. While stirring component B obtained in S2, add component A obtained in S1. After adding, continue to stir for 8 - 10 min to obtain the polyurethane waterproof coating.
[0010] Further, the preparation method of the modified multi-walled carbon nanotubes is as follows:
[0011] A1. After drying the multi-walled carbon nanotubes, take 3 g and place it in a flask. Add 200 - 220 mL of sulfuric acid solution, and stir magnetically for 12 h. Then add 70 - 75 mL of nitric acid solution to the flask, heat, stir, and carry out condensation reflux at 80 °C for 70 - 80 min to obtain the first mixed solution;
[0012] A2. Add 4200 - 4500 mL of deionized water to the first mixed solution obtained in A1. Stir while adding deionized water. After adding, let it stand, and then pour out the supernatant to obtain the remaining solution;
[0013] A3. Filter the remaining solution obtained in A2 by suction filtration to obtain the product. Wash it with deionized water multiple times to make the pH value of the product neutral. Then vacuum dry the product to a constant weight to obtain the modified multi-walled carbon nanotubes.
[0014] Further, in A1, the specific operation of the drying treatment is: place the multi-walled carbon nanotubes in a vacuum drying oven and dry them at 40 - 45 °C for 20 - 24 h.
[0015] Further, in A1, the concentrations of both the sulfuric acid solution and the nitric acid solution are 1.5 mol / L.
[0016] Further, in A2, the stirring speed is 150 - 180 r / min; the standing time is 20 - 24 h.
[0017] Further, in S1, the stirring speed is 180 - 210 r / min, and the stirring time is 15 - 20 min.
[0018] Further, in S2, the stirring speed is 230 - 250 r / min, and stir for 15 - 20 min.
[0019] Further, in S3, the stirring speed is 260 - 300 r / min.
[0020] This application has the following beneficial effects:
[0021] The polyurethane waterproof coating of the present invention includes calcium carbonate, potassium fulvate, and modified multi-walled carbon nanotubes. Potassium fulvate has good solubility, strong interaction ability with metal ions, and strong complexing ability. The functional groups of potassium fulvate can form chemical bonds with calcium ions / carbonate ions on the surface of calcium carbonate. For example, carboxyl groups chelate with calcium ions to form stable coordination bonds to enhance the binding force between potassium fulvate and calcium carbonate.
[0022] The functional groups of potassium fulvate can also interact with the active groups on the surface of the modified multi-walled carbon nanotubes, such as forming a certain combination through hydrogen bonds, electrostatic attraction, etc., to make the combination between potassium fulvate and the modified multi-walled carbon nanotubes more stable and firm.
[0023] In summary, potassium fulvate plays a bridging role here, tightly binding calcium carbonate and modified multi-walled carbon nanotubes together, enabling the modified multi-walled carbon nanotubes to form a continuous and dense protective film on the surface of calcium carbonate. The protective film has a certain thickness and strength, effectively preventing external acidic substances from contacting calcium carbonate particles to ensure that the coating film can maintain good waterproof and mechanical properties in an acidic environment. Description of the Drawings
[0024] Figure 1 、Trend chart of the comparison of tensile strength test data of the coating films made from the polyurethane waterproof coatings of Examples 1 - 3 and Comparative Examples 1 - 3 in the present invention before and after acid soaking;
[0025] Figure 2 、Trend chart of the comparison of the retention rate data of tensile strength of the coating films made from the polyurethane waterproof coatings of Examples 1 - 3 and Comparative Examples 1 - 3 in the present invention before and after acid soaking. Detailed Embodiments
[0026] The following further elaborates on the present application in conjunction with the embodiments.
[0027] Unless otherwise specified, the raw materials of the embodiments and comparative examples of the present application are all commercially available.
[0028] Example 1: (1) Preparation of modified multi-walled carbon nanotubes, and the preparation method is as follows:
[0029] A1. Perform a drying treatment on the multi-walled carbon nanotubes. The specific operation of the drying treatment is: Place the multi-walled carbon nanotubes in a vacuum drying oven and dry them at 42°C for 22 h. Then take 3 g and place it in a flask, add 210 mL of sulfuric acid solution, and magnetically stir at a speed of 180 r / min for 12 h. Then add 72 mL of nitric acid solution to the flask, heat, stir (180 r / min), and perform condensation reflux at 80°C for 75 min to obtain a first mixed solution.
[0030] Among them, the concentrations of both the sulfuric acid solution and the nitric acid solution are 1.5 mol / L. The multi-walled carbon nanotubes are purchased from Shanghai Yaotian New Material Technology Co., Ltd.
[0031] A2. Add 4500 mL of deionized water to the first mixed solution obtained in A1, and while adding the deionized water, perform uniform stirring at a stirring speed of 160 r / min. After adding, let it stand for 22 h, and then pour out the supernatant to obtain a remaining solution.
[0032] A3. Perform suction filtration on the remaining solution obtained in A2, with a filter membrane of 0.8 μm nylon membrane, to obtain a product. Wash the product three times with deionized water to make the pH value of the product neutral, and then vacuum dry the product to a constant weight to obtain the modified multi-walled carbon nanotubes.
[0033] (2) A preparation method of a polyurethane waterproof coating, comprising the following steps:
[0034] S1. By weight, mix 7 parts of rutile titanium dioxide, 3 parts of silicon powder, 14 parts of calcium carbonate, 5.5 parts of fulvic acid potassium powder, and 12.5 parts of modified multi-walled carbon nanotubes, and stir evenly at a stirring speed of 200 r / min for 16 min to obtain Component A.
[0035] S2. Mix 78 parts of polyurethane emulsion, 20 parts of styrene-acrylic emulsion, 4 parts of dispersant, and 14 parts of water, and stir evenly at a stirring speed of 240 r / min for 18 min to obtain Component B.
[0036] S3. While stirring Component B obtained in S2 evenly at a stirring speed of 280 r / min, slowly add Component A obtained in S1. After the addition is complete, continue stirring for 9 min to obtain the polyurethane waterproof coating.
[0037] Among them, the rutile titanium dioxide is rutile titanium dioxide JCR-806, purchased from Shaanxi Jinchuan Titanium Industry and Trade Co., Ltd. The silicon powder (content ≥ 99.9%, grade CY-Si992) is purchased from Qinghe County Chuangying Metal Materials Co., Ltd. The calcium carbonate powder (first grade) is purchased from Lingshou County Huixin Mining and Processing Factory. The fulvic acid potassium powder is ore-source fulvic acid potassium, purchased from Shandong Binhai Biotechnology Co., Ltd. The polyurethane emulsion is a high-solid-content waterborne polyurethane emulsion, purchased from Guangzhou Huimai Industrial Co., Ltd. The styrene-acrylic emulsion (industrial grade) is purchased from Shandong Jinhai Chemical Technology Co., Ltd. The dispersant is TD-1106, purchased from Shanghai Jiuyou Chemical Technology Co., Ltd.
[0038] Example 2: The difference between this example and Example 1 is that a preparation method of a polyurethane waterproof coating, comprising the following steps:
[0039] S1. By weight, mix 6 parts of rutile titanium dioxide, 2 parts of silicon powder, 13 parts of calcium carbonate, 5 parts of fulvic acid potassium powder, and 12 parts of modified multi-walled carbon nanotubes, and stir evenly at a stirring speed of 180 r / min for 20 min to obtain Component A.
[0040] S2. Mix 75 parts of polyurethane emulsion, 18 parts of styrene-acrylic emulsion, 3 parts of dispersant, and 13 parts of water, and stir evenly at a stirring speed of 230 r / min for 20 min to obtain Component B.
[0041] S3. While stirring Component B obtained in S2 evenly at a stirring speed of 260 r / min, slowly add Component A obtained in S1. After the addition is complete, continue stirring for 10 min to obtain the polyurethane waterproof coating.
[0042] Example 3: The difference between this example and Example 1 is that a preparation method of a polyurethane waterproof coating, comprising the following steps:
[0043] S1. By weight, mix 9 parts of titanium dioxide, 4 parts of silicon powder, 15 parts of calcium carbonate, 6 parts of fulvic acid potassium powder, and 13 parts of modified multi-walled carbon nanotubes, and stir evenly at a stirring speed of 210 r / min for 15 min to obtain Component A.
[0044] S2. Mix 80 parts of polyurethane emulsion, 22 parts of styrene-acrylic emulsion, 5 parts of dispersant, and 16 parts of water, and stir evenly at a stirring speed of 250 r / min for 15 min to obtain Component B.
[0045] S3. While stirring Component B obtained in S2 evenly at a stirring speed of 300 r / min, slowly add Component A obtained in S1. After the addition is complete, continue stirring for 8 min to obtain the polyurethane waterproof coating.
[0046] Comparative Example 1: The difference between this comparative example and Example 1 is that the fulvic acid potassium powder is deleted, and the modified multi-walled carbon nanotubes are replaced with titanium dioxide.
[0047] Specifically, a preparation method of a polyurethane waterproof coating includes the following steps:
[0048] S1. By weight, mix 19.5 parts of titanium dioxide, 3 parts of silicon powder, and 14 parts of calcium carbonate, and stir evenly at a stirring speed of 200 r / min for 16 min to obtain Component A.
[0049] S2. Mix 78 parts of polyurethane emulsion, 20 parts of styrene-acrylic emulsion, 4 parts of dispersant, and 14 parts of water, and stir evenly at a stirring speed of 240 r / min for 18 min to obtain Component B.
[0050] S3. While stirring Component B obtained in S2 evenly at a stirring speed of 280 r / min, slowly add Component A obtained in S1. After the addition is complete, continue stirring for 9 min to obtain the polyurethane waterproof coating.
[0051] Comparative Example 2: The difference between this comparative example and Example 1 is that the modified multi-walled carbon nanotubes are replaced with titanium dioxide.
[0052] Specifically, a preparation method of a polyurethane waterproof coating includes the following steps:
[0053] S1. By weight, mix 19.5 parts of titanium dioxide, 3 parts of silicon powder, 14 parts of calcium carbonate, and 5.5 parts of fulvic acid potassium powder, and stir evenly at a stirring speed of 200 r / min for 16 min to obtain Component A.
[0054] S2. Mix 78 parts of polyurethane emulsion, 20 parts of styrene-acrylic emulsion, 4 parts of dispersant, and 14 parts of water, and stir evenly at a stirring speed of 240 r / min for 18 min to obtain Component B.
[0055] S3. While uniformly stirring the B component obtained in S2 at a stirring speed of 280 r / min, slowly add the A component obtained in S1. After the addition is complete, continue stirring for 9 min to obtain the polyurethane waterproof coating.
[0056] Comparative Example 3: The difference between this comparative example and Example 1 is that potassium fulvate powder is deleted.
[0057] Specifically, a preparation method of a polyurethane waterproof coating includes the following steps:
[0058] S1. By weight, mix 7 parts of titanium dioxide, 3 parts of silicon powder, 14 parts of calcium carbonate, and 12.5 parts of modified multi-walled carbon nanotubes, and uniformly stir at a stirring speed of 200 r / min for 16 min to obtain the A component.
[0059] S2. Mix 78 parts of polyurethane emulsion, 20 parts of styrene-acrylic emulsion, 4 parts of dispersant, and 14 parts of water, and uniformly stir at a stirring speed of 240 r / min for 18 min to obtain the B component.
[0060] S3. While uniformly stirring the B component obtained in S2 at a stirring speed of 280 r / min, slowly add the A component obtained in S1. After the addition is complete, continue stirring for 9 min to obtain the polyurethane waterproof coating.
[0061] Test Example: Test objects: The polyurethane waterproof coatings prepared in Examples 1 - 3 and Comparative Examples 1 - 3.
[0062] Test items: ① Tensile strength; ② Tensile strength retention rate after acid treatment (2% H 2 SO 4 , 168 h).
[0063] Test basis: GB / T 19250 - 2013 "Polyurethane Waterproof Coating".
[0064] Test results: See Table 1.
[0065] Table 1. Test data of the test example
[0066]
[0067]
[0068] Result analysis: Analyze Examples 1 - 3 and combine the data in Table 1 and Figure 1 - Figure 2 It can be seen that after the film is acid-treated (2% H 2 SO 4, 168h) the tensile strength retention rate is as high as 93.52% or more, indicating that the coating film formed by the polyurethane waterproof coating of the present invention (Example 1-Example 3) can maintain good waterproof and mechanical properties in an acidic environment.
[0069] Analyze Example 1 and Comparative Examples 1-3 and combine the data in Table 1 and Figure 1 - Figure 2 By comparing Comparative Example 1 with Comparative Example 2, it can be seen that the addition of potassium humate powder alone will lead to the coating acid treatment (2% H 2 SO 4 , 168h) tensile strength retention rate decreases. This is because potassium humate itself has good solubility, and its rich variety of hydrophilic groups will be introduced into the coating system, increasing the hydrophilicity of the entire system; in an acidic environment, moisture is more likely to penetrate into the coating, providing more medium for the reaction of acidic substances with calcium carbonate, accelerating the reaction, thereby reducing the acid resistance of calcium carbonate. As the reaction of acidic substances with calcium carbonate intensifies, the surface of calcium carbonate particles will gradually be eroded, its chemical structure and physical state are destroyed, the originally tight structure becomes loose, and even partially dissolved phenomena may occur, resulting in a decrease in the mechanical properties (tensile strength) of the coating.
[0070] From the comparison between Comparative Example 1 and Comparative Example 3, it can be seen that the addition of modified multi-walled carbon nanotubes alone can improve the coating acid treatment (2% H 2 SO 4 , 168h) tensile strength retention rate. Combined with Example 1, it can be seen that in the presence of calcium carbonate, the modified multi-walled carbon nanotubes and potassium humate can produce a synergistic effect and synergistically improve the acid treatment (2% H 2 SO 4 , 168h) tensile strength retention rate. This is because potassium humate has good solubility, strong interaction ability with metal ions, and strong complexing ability. The functional groups of potassium humate can form chemical bonds with calcium ions / carbonate ions on the surface of calcium carbonate, such as carboxyl groups chelating with calcium ions to form stable coordination bonds to enhance the binding force between potassium humate and calcium carbonate. The functional groups of potassium humate can also interact with the active groups on the surface of modified multi-walled carbon nanotubes, such as forming a certain bond through hydrogen bonds, electrostatic attraction, etc., so that the bond between potassium humate and modified multi-walled carbon nanotubes is more stable and firm. When the three exist at the same time, potassium humate plays a bridging role, tightly combining calcium carbonate and modified multi-walled carbon nanotubes, so that the modified multi-walled carbon nanotubes form a continuous and dense protective film on the surface of calcium carbonate. The protective film has a certain thickness and strength, which effectively prevents external acidic substances from contacting calcium carbonate particles, thereby synergistically improving the coating acid treatment (2% H 2 SO 4 , 168h) tensile strength retention rate.
[0071] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any suitable way without conflict. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.
[0072] In addition, any combination can also be made among various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.
Claims
1. A method for preparing a polyurethane waterproof coating, characterized in that: The steps include: S1. Mix 6-9 parts of titanium dioxide, 2-4 parts of silicon powder, 13-15 parts of calcium carbonate, 5-6 parts of potassium humate powder and 12-13 parts of modified multi-walled carbon nanotubes by weight, and stir to obtain component A; S2, mixing 75-80 parts of polyurethane emulsion, 18-22 parts of styrene-acrylic emulsion, 3-5 parts of dispersant and 13-16 parts of water, stirring to obtain component B; S3. While stirring component B obtained in S2, add component A obtained in S1. After the addition is completed, continue stirring for 8-10 minutes to obtain the polyurethane waterproof coating.
2. The method for preparing the polyurethane waterproof coating according to claim 1, characterized in that: The preparation method of the modified multi-walled carbon nanotubes is as follows: A1. After drying the multi-walled carbon nanotubes, 3 g of the multi-walled carbon nanotubes were placed in a flask, 200-220 mL of sulfuric acid solution was added, and magnetic stirring was performed for 12 h. Then, 70-75 mL of nitric acid solution was added to the flask, and the mixture was heated at 80° C., stirred, and condensed and refluxed for 70-80 min to obtain a first mixed solution. A2, add 4200-4500 mL of deionized water to the first mixed solution obtained in A1, stir while adding the deionized water, let it stand after adding, and then pour out the supernatant to obtain a residual solution; A3. Filter the remaining solution obtained in A2 to obtain a product, wash it with deionized water for multiple times to make the pH value of the product neutral, and then vacuum dry the product to constant weight to obtain modified multi-walled carbon nanotubes.
3. The method for preparing the polyurethane waterproof coating according to claim 2, characterized in that: In A1, the specific operation of the drying treatment is: placing the multi-walled carbon nanotubes in a vacuum drying oven and drying them at 40-45° C. for 20-24 hours.
4. The method for preparing the polyurethane waterproof coating according to claim 2, characterized in that: In A1, the concentrations of the sulfuric acid solution and the nitric acid solution are both 1.5 mol / L.
5. The method for preparing the polyurethane waterproof coating according to claim 2, characterized in that: In A2, the stirring speed is 150-180r / min; the standing time is 20-24h.
6. The method for preparing the polyurethane waterproof coating according to claim 1, characterized in that: In S1, the stirring speed is 180-210 r / min, and the stirring time is 15-20 min.
7. The method for preparing the polyurethane waterproof coating according to claim 1, characterized in that: In S2, the stirring speed is 230-250 r / min, and the stirring is performed for 15-20 min.
8. The method for preparing the polyurethane waterproof coating according to claim 1, characterized in that: In S3, the stirring speed is 260-300 r / min.