An acrylic polymer cement waterproof coating and its preparation method

Abstract

This invention discloses an acrylic polymer cement waterproof coating and its preparation method. The waterproof coating comprises: component A and component B; component A includes: acrylic emulsion, amino silicone oil emulsion, water, protic acid catalyst, defoamer, dispersant, and thickener; component B includes: cement, calcium carbonate, nano-silica particles, cellulose ether, and retarder. Through formulation optimization, the waterproof coating of this invention exhibits good adhesive strength and permeability.

Description

Technical Field

[0001] This invention belongs to the field of waterproof coating technology, and more specifically, relates to an acrylic polymer cement waterproof coating and its preparation method. Background Technology

[0002] Through internal solvent evaporation or molecular chain reactions, resins, emulsions, and polymers possess excellent film-forming properties. The resulting highly dense film provides excellent barrier properties against liquids and gases, preventing these media from penetrating through the film layer and affecting the substrate. Utilizing this property, resins, emulsions, and polymers are often used as effective components in waterproof coatings. However, the adhesion, elongation, and permeability of the waterproof coating film often determine its waterproofing effect.

[0003] As a crucial indicator of the waterproofing performance of waterproof coatings, the stronger the adhesion between the film and the substrate, the less likely the coating is to detach from the base layer, resulting in better retention and effectiveness of the waterproof coating. Currently, most waterproof coatings on the market rely primarily on physical adsorption to bond with the substrate. This bonding force is easily affected by factors such as the looseness of the substrate, external water pressure, acid, alkali, and salt corrosion, and the thermal expansion and contraction of the substrate, leading to film detachment, significantly reduced waterproofing effect, or even failure, ultimately damaging building materials. Therefore, researchers have begun to focus on waterproof coatings with reactive properties. After being applied to the substrate surface, the active functional groups within these coatings cross-link and solidify with the active sites on the substrate, forming high-strength chemical bonds. This enhances the interaction between the coating and the substrate, inhibiting the risk of coating detachment. However, the distribution and number of active sites on concrete substrates are often fixed, which limits the interaction points between reactive coatings and the substrate, thus restricting the improvement of coating adhesion.

[0004] Furthermore, minor cracks, structural defects, and loose surfaces are inevitable during cement concrete construction. These defects can easily lead to water seepage and retention under the waterproofing layer, inevitably causing blistering and bulging over time, reducing the durability of the waterproofing. While existing acrylic polymer cementitious waterproofing coatings can form a waterproof film on the concrete substrate, achieving a good waterproofing effect, their high viscosity means that when applied to the concrete surface, they can only cover a large area of ​​the substrate and cannot effectively penetrate and bond to these defects, resulting in certain defects and risks in the waterproofing process. Summary of the Invention

[0005] The purpose of this invention is to provide an acrylic polymer cement waterproof coating and its preparation method. Through formulation optimization, the prepared acrylic polymer cement waterproof coating has good adhesion strength and permeability.

[0006] To achieve the above objectives, one aspect of the present invention provides an acrylic polymer cement waterproof coating, which comprises: component A and component B;

[0007] Component A includes: acrylic emulsion, amino silicone oil emulsion, water, protic acid catalyst, defoamer, dispersant and thickener;

[0008] Component B includes: cement, calcium carbonate, nano-silica particles, cellulose ether, and retarder.

[0009] In this invention, the amino silicone oil emulsion contained in component A has an amino-terminated silicone oil that acts as a bridge, effectively connecting the acrylic coating and the concrete substrate through a chemical reaction (by forming chemical bonds with hydrated calcium silicate or calcium aluminate), improving the adhesion of the coating and making the waterproofing more effective, reliable, and durable.

[0010] The nano-sized silica particles in component B of this invention, upon dissolving in water, form a silica sol rich in silanol (Si-OH) groups. On one hand, this sol reacts with active sites on the concrete substrate, adhering to the substrate surface and increasing the number of active sites, thus increasing the interaction sites between the coating and the substrate. More active molecular chains adhere to the concrete, further enhancing adhesion. On the other hand, it chemically reacts with the amino groups at the ends of the siloxane chains and the ester groups in the acrylic acid in component A, improving the crosslinking between the powder interface and the emulsion segments, thus addressing the problem of insufficient bonding between the emulsion coating layer and the powder interface, resulting in poor water resistance of the coating film.

[0011] According to the present invention, preferably, component A comprises, by weight parts: 75-80 parts acrylic emulsion, 5-8 parts amino silicone oil emulsion, 9-11 parts water, 0.02-0.05 parts protic acid catalyst, 0.5-1 parts defoamer, 0.02-0.05 parts dispersant and 0.02-0.05 parts thickener;

[0012] By mass, component B comprises: 28-30 parts cement, 60-64 parts calcium carbonate, 4-6 parts nano silica particles, 0.04-0.06 parts cellulose ether, and 0.01-0.04 parts retarder.

[0013] According to the present invention, preferably, the nano-silica particles are hydrophilic fumed silica;

[0014] The particle size of the nano-silica particles is 100–500 nm.

[0015] According to the present invention, preferably, the particle size of the amino silicone oil emulsion is 10-100 nm.

[0016] The amino silicone oil emulsion and nano silica particles used in this invention, due to their smaller particle size (<1μm), are more likely to penetrate into the tiny cracks in the concrete substrate, thereby blocking the cracks, reducing water seepage and water retention, and improving the waterproofing life and effect.

[0017] According to the present invention, preferably, the acrylic emulsion is Wanhua 8316A;

[0018] The acrylic emulsion has a particle size of 0.25-0.35 μm.

[0019] According to the present invention, preferably, the protic acid catalyst is citric acid; the defoamer is a polyether-type defoamer; and the thickener is an alkali-swellable thickener.

[0020] According to the present invention, preferably, the cement is P.O32.5 white cement;

[0021] The retarder is sodium gluconate.

[0022] According to the present invention, preferably, the mass ratio of component A to component B is 1:(0.85-1.2).

[0023] In this invention, component A mainly consists of acrylic emulsion, amino silicone oil emulsion, water, citric acid, defoamer, dispersant, and thickener. Acrylic emulsion, as the main film-forming substance, is applied to the concrete substrate. As the water in the coating evaporates, the emulsion particles gradually aggregate and cross-link, eventually forming a dense waterproof film. Amino silicone oil emulsion, acting as a bridging and penetrating agent, connects the acrylic coating and the concrete substrate through a chemical reaction, improving the incompatibility between the emulsion chain segments and the powder interface. Its smaller particle size allows it to penetrate into the fine cracks in the substrate, effectively blocking cracks and reducing water seepage and water retention. Citric acid, as a catalyst, provides protons, effectively ensuring the cross-linking reaction between the amino groups on the upper end of the silicone oil and the hydrated calcium silicate or calcium aluminate in the concrete substrate, as well as the silica sol formed by the nano-sized silica particles in the powder. Defoamer, as an auxiliary material, mainly eliminates air bubbles in the coating to improve the density of the film. The addition of dispersant can effectively improve the compatibility between the components in the coating, ensuring the uniformity of the coating and the smoothness of the film. Thickener can effectively ensure the fluidity of the coating, the thickness of the coating application, and the waterproof efficiency of the film.

[0024] Component B mainly consists of P.O32.5 white cement, calcium carbonate, nano-silica particles, cellulose ether, and a retarder. P.O32.5 white cement acts as a film-forming substance; after the clinker minerals react chemically with water, the components begin to dissolve, forming hydrates. The products gradually deposit and harden, forming a solid film. Calcium carbonate serves as the main filler and support material, enhancing the strength and stability of the waterproof film formed by the polymer emulsion. Nano-silica particles act as a penetrant and binder, dissolving in water to form a silica sol rich in silanol (Si-OH) groups. On one hand, they react with active sites on the concrete substrate, adhering to the substrate surface and increasing the number of active sites, thus increasing the number of molecular chains attached to the surface and further enhancing the interaction between the coating and the substrate. On the other hand, they react chemically with the amino groups at the ends of the siloxane chains and the ester groups in the acrylic acid in Component A, improving the cross-linking between the powder interface and the emulsion segments, thus addressing the problem of insufficient bonding between the emulsion coating layer and the powder interface, resulting in poor water resistance of the coating. Cellulose ethers can effectively ensure the smoothness and waterproofing of the coating film after it is applied to the wall; as a substance that reduces the cement hydration rate, retarders can provide sufficient time for the two components to react fully, ensuring the cross-linking between the concrete substrate and the coating components.

[0025] The two-component, permeable, reactive acrylic polymer cementitious waterproof coating provided by this invention involves cross-linking reactions between its components, such as... Figure 1 As shown.

[0026] Another aspect of the present invention provides a method for preparing the above-mentioned waterproof coating, the method comprising:

[0027] The acrylic emulsion, amino silicone oil emulsion, water, protic acid catalyst, defoamer, dispersant and thickener are mixed evenly to obtain component A;

[0028] The cement, calcium carbonate, nano-silica particles, cellulose ether, and retarder are mixed evenly to obtain component B.

[0029] According to the present invention, preferably, the preparation method includes:

[0030] The acrylic emulsion, amino silicone oil emulsion and water are stirred and mixed, then a mixture of thickener and defoamer is added and stirred and mixed, then a dispersant and citric acid are added and stirred and mixed again to obtain component A;

[0031] The calcium carbonate and cement are mixed, and then nano-silica particles, cellulose ether and retarder are added and stirred to obtain component B.

[0032] As a preferred embodiment, the preparation method of the present invention includes:

[0033] Component A: After metering the acrylic emulsion, add it to the liquid mixing tank, turn on the disperser, and maintain a speed of 600-750 r / min. Then, in the first step, add water and amino silicone oil emulsion to the emulsion system according to the specified ratio and stir for 5 minutes. In the second step, weigh a certain amount of thickener, dissolve it in the defoamer, and then slowly add it dropwise to the emulsion system, stirring for 5 minutes. In the third step, slowly add the weighed dispersant and citric acid to the above system, stirring for 5 minutes. Finally, stir the entire mixture for 5 minutes to obtain the desired Component A.

[0034] Component B: Add calcium carbonate to the powder mixing tank (power 70-80HZ), start the mixing, then weigh out a certain amount of P.O32.5 white cement and add it, and stir for 3 minutes; then weigh out a certain amount of nano silica particles, cellulose ether and retarder and add them to the above system, and stir the whole mixture for 3 minutes to obtain the required Component B.

[0035] The technical solution of the present invention has the following beneficial effects:

[0036] (1) The amino silicone oil emulsion used in component A of this invention connects the acrylic emulsion coating layer and the concrete base layer through a chemical reaction (by forming chemical bonds with hydrated calcium silicate or calcium aluminate), enhances the interaction force between the coating and the concrete, improves the adhesion strength of the coating, and makes the waterproofing of the coating more effective, reliable and durable.

[0037] (2) The nano-sized silica particles used in component B of this invention can solve the problem of insufficient active sites on the concrete substrate when existing reactive coatings bond with the substrate. When dissolved in water, they form a silica sol rich in silanol (Si-OH) groups. This silica sol reacts with the active sites on the concrete substrate and adheres to the substrate surface, thereby increasing the number of active sites on the concrete substrate. A large number of active sites can form numerous bonding points, enhancing the interaction between the coating and the substrate and improving the adhesion performance of the coating.

[0038] (3) The nano-sized silica particles used in component B of this invention can solve the problem of insufficient bonding between the emulsion coating layer and the powder interface in existing coatings. The hydrolyzed silica sol reacts chemically with the amino groups at the ends of the siloxane chains in component A and the ester groups in the acrylic acid, enhancing the interaction between the two components and improving the coating effect.

[0039] (4) The use of small-particle-size amino silicone oil emulsion and nano-silica particles in this invention can effectively improve the problem that existing coatings cannot penetrate into the micro-cracks and defects of concrete substrates. Its nano-sized particle size can ensure its effective penetration and migration into the concrete substrate, thereby blocking cracks, reducing water seepage and water retention, and improving the waterproofing life and effect.

[0040] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0041] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0042] Figure 1 A schematic diagram of the cross-linking reaction of the components in the acrylic polymer cement waterproof coating according to the present invention is shown.

[0043] Figure 2 The test results diagram of Test Example 2 according to the present invention is shown. Detailed Implementation

[0044] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0045] The present invention is further illustrated by the following examples:

[0046] In the following examples and comparative examples, the acrylic emulsion used was Wanhua 8316A with a particle size of 0.25-0.35 μm;

[0047] The nano-silica particles are hydrophilic fumed silica with a particle size of 100-500 nm. They were purchased from Hubei Huifu Nanomaterials Co., Ltd., and the grade is HL-200.

[0048] The amino silicone oil emulsion is Dow Corning DC-949, with a silicone content of 35% (by weight) and a particle size of 10–100 nm.

[0049] Citric acid was purchased from Suzhou Zhuosheng Environmental Protection Technology Co., Ltd., with a citric acid content of 99%.

[0050] The defoamer is B-299 (polyether type defoamer) from Guangdong Zhonglianbang Fine Chemical Co., Ltd.

[0051] The dispersant is F497 from Guangdong Aona Polymer Co., Ltd.;

[0052] The thickener is Dow thickener Al-Shun RM-8W (alkali-swellable thickener);

[0053] The white cement is PO 32.5 white cement from Alboportland (Anqing) Co., Ltd.;

[0054] Calcium carbonate is from Xinjia New Materials Co., Ltd., mesh size: 280 mesh;

[0055] The cellulose ether is Celanese MHG22;

[0056] The retarder was sodium gluconate, purchased from Wujiang Xulong Chemical Co., Ltd.

[0057] Example 1

[0058] Component A: Weigh 800g of acrylic emulsion and add it to the liquid mixing tank. Turn on the disperser and maintain the speed at 700r / min. Then weigh 110g of water and 40g of amino silicone oil emulsion and add them to the emulsion system. Stir for 5min. Next, dissolve 0.5g of thickener in 10g of defoamer and slowly add the mixture of thickener and defoamer dropwise to the emulsion system. Stir for 5min. Finally, weigh 0.5g of dispersant and 0.5g of citric acid and add them to the above emulsion system. Stir for 5min. Finally, stir the whole mixture for 5min to obtain Component A.

[0059] Component B: Weigh 640g of calcium carbonate and add it to the mixing tank (74HZ), then start the mixing; then weigh 300g of white cement and add it to the mixture, and stir for 3 minutes; finally, weigh 60g of nano silica particles, 0.6g of cellulose ether and 0.4g of retarder and add them to the above system, and finally stir the whole mixture for 3 minutes to obtain Component B.

[0060] Example 2

[0061] The difference between this embodiment and Embodiment 1 is that the amount of amino silicone oil emulsion added in component A is changed to 50g.

[0062] Example 3

[0063] The difference between this embodiment and Example 1 is that the amount of amino silicone oil emulsion added in component A is changed to 80g.

[0064] Example 4

[0065] The difference between this embodiment and Embodiment 1 is that the amount of amino silicone oil emulsion added in component A is changed to 90g.

[0066] Example 5

[0067] The difference between this embodiment and Embodiment 3 is that the amount of nano-silica particles added in component B is changed to 40g.

[0068] Comparative Example 1

[0069] The difference between this comparative example and Example 1 is that the amount of amino silicone oil emulsion added in component A is changed to 0g; and the amount of nano silica particles added in component B is changed to 0g.

[0070] Comparative Example 2

[0071] The difference between this comparative example and Example 3 is that the amount of nano-silica particles added in component B is changed to 0g.

[0072] Comparative Example 3

[0073] The difference between this comparative example and Example 3 is that the amount of amino silicone oil emulsion added in component A is changed to 0g.

[0074] Test Example 1

[0075] The components A and B described in Examples 1-5 and Comparative Examples 1-3 were mixed at a 1:1 ratio (by mass) to prepare a coating. Samples for testing adhesion performance were then prepared and cured according to the requirements of standard GB / T 23445-2009 "Polymer Cement Waterproof Coatings". The test results of the adhesion strength of the relevant samples are shown in the table below:

[0076] Table 1

[0077] result Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Bond strength / MPa 1.20 1.34 1.52 1.56 1.29 0.95 1.12 1.05

[0078] As shown in the table, the adhesive strength of the sample without added amino silicone oil emulsion and nano silica particles (Comparative Example 1) was only 0.95 MPa. The adhesive strength of the coatings with added amino silicone oil emulsion and nano silica particles alone (Comparative Examples 2 and 3) was improved to some extent. This indicates that both components undergo a cross-linking reaction with the substrate, forming stronger chemical bonds, inhibiting the coating from detaching from the substrate surface, increasing the coating's adhesive strength, and significantly improving its waterproofing effect.

[0079] Comparing Comparative Examples 2 and 3 with Example 3, it was found that adding equal amounts of amino silicone oil emulsion and nano silica particles to the coating significantly improved the adhesion performance. Example 3 achieved the best performance, with an adhesion strength of 1.52 MPa, an increase of 60.0% compared to Comparative Example 1, 35.7% compared to Comparative Example 2, and 44.8% compared to Comparative Example 3. This indicates that there is also an interaction between the amino silicone oil emulsion and the nano silica particles. Furthermore, the sol generated after the hydrolysis of the nano silica particles penetrates into the substrate and first reacts chemically with the active sites of the substrate. The excess hydroxyl groups on the sol surface provide more active sites, allowing more amino silicone oil emulsion and acrylic emulsion to react with these sites, enhancing the adhesion between the coating and the substrate, further improving the coating's adhesion, making the waterproofing more effective, reliable, and durable. It can also be seen that after the amount of amino silicone oil emulsion used reaches a certain level (Examples 3 and 4), the trend of change in bonding strength slows down. This may be because there are limited active sites on the concrete substrate that can undergo chemical reactions, resulting in excess amino silicone oil emulsion being unable to react with the substrate, and the bonding effect cannot be further increased.

[0080] Test Example 2

[0081] This test example provides a direct illustration of the reaction and penetration effect of the coating prepared by this invention on a concrete substrate. The specific test method is as follows: Components A and B of Comparative Example 1 and Example 3 were prepared by mixing and stirring at a 1:1 (mass ratio) to form coatings. These coatings were then applied to the concrete substrate, with a film thickness of 1.3 mm. After the coatings formed and dried, they were peeled off, and the morphology is as follows. Figure 2 As shown.

[0082] from Figure 2 As can be seen, in Comparative Example 1 (without added amino silicone oil emulsion and nano silica particles), the coating completely detached from the concrete substrate after testing. This indicates that the coating did not interact with the concrete substrate, but only adhered to its surface, and detached directly from the substrate under external force. In Example 3, the coating remained largely adhered to the concrete after testing, and even at the detached areas, there were obvious traces of penetration and chemical reaction. This indicates that the coating underwent a significant chemical reaction and penetration with the concrete substrate, forming stronger chemical bonds with the substrate, inhibiting the risk of the coating film detaching from the substrate surface under external force, and significantly improving the waterproofing effect of the coating.

[0083] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. An acrylic polymer cement waterproof coating, characterized in that, This waterproof coating comprises: Component A and Component B; By weight, component A comprises: 75-80 parts acrylic emulsion, 5-8 parts amino silicone oil emulsion, 9-11 parts water, 0.02-0.05 parts protic acid catalyst, 0.5-1 part defoamer, 0.02-0.05 parts dispersant, and 0.02-0.05 parts thickener; By mass, component B comprises: 28-30 parts cement, 60-64 parts calcium carbonate, 4-6 parts nano silica particles, 0.04-0.06 parts cellulose ether, and 0.01-0.04 parts retarder.

2. The waterproof coating according to claim 1, wherein, The nano-silica particles are hydrophilic fumed silica. The particle size of the nano-silica particles is 100–500 nm.

3. The waterproof coating according to claim 1, wherein, The particle size of the amino silicone oil emulsion is 10–100 nm.

4. The waterproof coating according to claim 1, wherein, The acrylic emulsion is Wanhua 8316A; The acrylic emulsion has a particle size of 0.25-0.35 μm.

5. The waterproof coating according to claim 1, wherein, The protic acid catalyst is citric acid; The defoamer is a polyether-type defoamer; The thickener is an alkali-swellable thickener.

6. The waterproof coating according to claim 1, wherein, The cement is P.O32.5 white cement; The retarder is sodium gluconate.

7. The waterproof coating according to claim 1, wherein, The mass ratio of component A to component B is 1:(0.85-1.2).

8. A method for preparing the waterproof coating according to any one of claims 1-7, characterized in that, The preparation method includes: The acrylic emulsion, amino silicone oil emulsion, water, protic acid catalyst, defoamer, dispersant and thickener are mixed evenly to obtain component A; The cement, calcium carbonate, nano-silica particles, cellulose ether, and retarder are mixed evenly to obtain component B.

9. The preparation method according to claim 8, wherein, The preparation method includes: The acrylic emulsion, amino silicone oil emulsion and water are stirred and mixed, then a mixture of thickener and defoamer is added and stirred and mixed, then a dispersant and citric acid are added and stirred and mixed again to obtain component A; The calcium carbonate and cement are mixed, and then nano-silica particles, cellulose ether and retarder are added and stirred to obtain component B.

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