Self-cleaning water-based exterior wall waterproof coating and preparation method thereof

Abstract

The application provides a self-cleaning water-based outer wall waterproof paint, which comprises the following components in mass fraction: 18-30% of a silicone-acrylate emulsion, 10-25% of a silicone resin emulsion, 5-15% of modified titanium dioxide, 5-15% of rutile titanium dioxide, 5-8% of super-hydrophobic talcum powder, 5-15% of heavy calcium carbonate, 3.3-6.1% of an additive, and the balance of water. Due to the good long-term hydrophobicity of the silicon compound in the emulsion molecular structure, the water molecules are prevented from penetrating into the paint film, and the long-chain alkyl of dodecyloxybenzoic acid increases the hydrophobicity of the titanium dioxide, so that good waterproof effect is achieved, the paint film is thicker and denser, the waterproof effect is better, the outer wall coating is fresh for a long time due to the lotus effect formed on the surface of the paint film, and the outer wall coating has strong hydrophobicity. Meanwhile, the application also has the advantages of simple construction, short construction period and low construction cost, and can be widely used for the decoration of surface coatings.

Description

A self-cleaning water-based exterior wall waterproof coating and its preparation method Technical Field

[0001] This invention relates to the field of building exterior wall coatings, and mainly to a self-cleaning water-based waterproof exterior wall coating and its preparation method. Background Technology

[0002] Currently, the main types of exterior wall coatings include stone-textured paint, multi-color paint, and latex paint, among which latex paint, as a traditional coating material, is widely used. However, latex paint is often eroded by external environmental factors such as ultraviolet rays, pollutants, and rainwater, resulting in discoloration, peeling, flaking, mold, and blackening, severely damaging the decorative effect. In current technology, exterior wall waterproofing mainly involves applying waterproof and crack-resistant leveling mortar, JS waterproof coating, or K11 rigid waterproof coating to a concrete base, followed by putty leveling and then coating. This construction method forms a continuous, dense coating layer on the wall surface (usually with a thickness of 1.5mm or more), preventing moisture from penetrating into the building structure, theoretically providing good waterproofing. However, in actual construction, large-area cracking often occurs after the waterproof layer is applied with putty, severely affecting the coating effect; secondly, the waterproof coating film thickness is relatively high, requiring multiple coats to achieve the desired result, leading to high construction costs and a significant load on the wall.

[0003] From a waterproofing perspective, existing technologies such as CN103666246A disclose a photocatalytic superhydrophilic transparent self-cleaning coating; CN103965677A discloses a paint film formed by water-based nano resin, nano Al2O3 slurry, etc., whose surface can be completely wetted by water and has a contact angle of less than 5°; however, all of the above solutions have the problem that the self-cleaning coating has good short-term effect but poor durability.

[0004] In conclusion, there is an urgent need to research and develop a new type of waterproof coating to solve the problems existing in the current technology. Summary of the Invention

[0005] This invention provides a self-cleaning water-based exterior wall waterproof coating and its preparation method. Addressing the problems of poor durability and complex construction of traditional waterproof coatings, this invention uses dodecyloxybenzoic acid-modified titanium dioxide to produce a synergistic effect with multiple components such as talc and resin, resulting in excellent hydrophobic properties. Compared with traditional styrene-acrylic latex paint, it can effectively delay the aging of the paint film, extend its service life, and overcome the defects of existing products.

[0006] One object of the present invention is to provide a self-cleaning water-based exterior wall waterproof coating, wherein the self-cleaning water-based exterior wall waterproof coating comprises the following components by mass fraction:

[0007]

[0008]

[0009] The modified titanium dioxide is dodecyloxybenzoic acid modified titanium dioxide.

[0010] Furthermore, the ultrafine hydrophobic talc powder has a fineness of ≤4.5μm and a SiO2 content of ≥59%.

[0011] Furthermore, the additives include dispersants, wetting agents, defoamers, thickeners, bactericides, film-forming aids, antifreeze agents, and pH adjusters.

[0012] Another object of the present invention is to provide a method for preparing the self-cleaning water-based exterior wall waterproof coating, the method comprising the following steps:

[0013] S1. After calcining titanium dioxide, add it to sodium hydroxide solution and sonicate to obtain an intermediate product.

[0014] S2. Using ethanol as a solvent, the intermediate product and dodecyloxybenzoic acid are mixed and reacted by ultrasonic heating to obtain modified titanium dioxide.

[0015] S3. Add some of the additives to water, stir, then add modified titanium dioxide, heavy calcium carbonate, rutile titanium dioxide and superhydrophobic talc, and stir to disperse to a certain fineness.

[0016] S4. Add silicone acrylic emulsion, silicone resin emulsion and other additives, stir and disperse until the viscosity is qualified, and obtain the self-cleaning water-based exterior wall waterproof coating.

[0017] Furthermore, the calcination temperature described in S1 is 400-600℃.

[0018] Furthermore, the concentration of the sodium hydroxide solution in S1 is 1-3 mol / L.

[0019] Furthermore, the molar ratio of the intermediate product and dodecyloxybenzoic acid in S2 is 1:4 to 1:6.

[0020] Furthermore, the ultrasonic heating reaction described in S2 is carried out at a temperature of 60-100℃ for a duration of 5-20 hours.

[0021] Furthermore, the fineness in S3 is <60μm.

[0022] Furthermore, the viscosity of S4 is 95-105 KU.

[0023] Further, step S3 is as follows: add cellulose thickener to water and disperse at 500-700 rpm for 5 min; then add wetting agent, dispersant, film-forming aid, defoamer, antifreeze agent, and pH adjuster in sequence and disperse at 600-800 rpm for 10 min; add modified titanium dioxide, heavy calcium carbonate, rutile titanium dioxide, and superhydrophobic talc powder, increase the speed to 1400-1600 rpm, and disperse for 20 min until the fineness is less than 60 μm.

[0024] Further, step S4 is as follows: reduce the rotation speed to 600-800 rpm, add silicone-acrylic emulsion, organosilicon resin emulsion and bactericide in sequence, and disperse for 10 min; finally add polyurethane thickener, stir and disperse for 15 min, and test the viscosity at 25℃ to 95-105 KU to obtain the product.

[0025] The present invention has the following beneficial effects:

[0026] 1. This invention provides a self-cleaning water-based exterior wall waterproof coating. The coating contains dodecyloxybenzoic acid-modified titanium dioxide, which, when combined with components such as silicone-acrylic emulsion, silicone resin emulsion, and superhydrophobic high-fineness talc, exhibits a good synergistic effect, improving various properties of the coating. This invention first calcines and ultrasonically treats the titanium dioxide with sodium hydroxide to remove outer impurities, resulting in more active hydroxyl groups on the surface. Then, it is mixed with dodecylbenzoic acid and ultrasonically heated to react, introducing alkyl chains and benzene rings onto the titanium dioxide surface through esterification. This not only enhances the dispersibility of the modified titanium dioxide but also improves its hydrophobicity, making it more compatible with silicone-acrylic emulsion, silicone resin emulsion, and other components, thus enhancing the product's stability and strength.

[0027] 2. In this invention, the silicon compound exhibits good long-lasting hydrophobicity in the emulsion molecular structure, preventing water molecules from penetrating into the paint film. Combined with modified titanium dioxide and superhydrophobic talc powder, which have long alkyl chains and phenyl structures, the product's hydrophobicity is further enhanced, achieving excellent waterproofing. The application method of this invention differs from conventional JS (polymer cement) waterproof coatings, resulting in a thicker, denser paint film with superior waterproofing. Furthermore, the paint film surface can exert a lotus leaf effect through its strong hydrophobic properties, allowing water droplets to carry away dust and other contaminants as they roll off, keeping the exterior wall coating looking new over time.

[0028] 3. Compared with traditional waterproof coatings, the self-cleaning water-based exterior wall waterproof coating of this invention exhibits excellent weather resistance. Compared with traditional styrene-acrylic latex paint, it can more effectively delay the aging of the paint film, thereby extending its service life. Simultaneously, this invention also has the advantages of simpler construction, shorter construction period, and lower construction cost. It can be widely used for surface coating decoration, reducing the huge social costs caused by the need for regular renovations due to dirt and aging of exterior walls. Detailed Implementation

[0029] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0030] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0031] It should be understood that, except in any operational instance or otherwise indicated, the amounts or all figures representing ingredients used, for example, in the specification and claims, should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​varying according to the desired performance to be obtained according to the invention.

[0032] The following raw materials are used in the embodiments of the present invention:

[0033] Silicone-acrylic emulsion, model number V-991P.

[0034] Silicone resin emulsion, a microparticle emulsion synthesized from silica, organosilicon and functional monomers, is designated as Showa Emulsion 8861.

[0035] Rutile titanium dioxide, also known as titanium dioxide, is designated as Dongjia SR-237.

[0036] Superhydrophobic talc powder, fineness ≤4.5μm, SiO2 content ≥59%, model number XFH-934071-Y6.

[0037] Heavy calcium carbonate, 800 mesh, model number Jiaoling Jinpeng JH-600.

[0038] The dispersant is a hydrophobically modified ammonium carboxylate copolymer, model number P26.

[0039] The wetting agent is an alkyl polyoxyethylene ether wetting agent, model number Klein LCN 407.

[0040] The defoamer is a mineral oil-based defoamer, model number BASF ST 2410AC.

[0041] Cellulose thickener, model number Rohm and Haas HBR250.

[0042] Polyurethane thickener, model number Rohm and Haas RM-8W.

[0043] The bactericide is Duvir MBS 5050.

[0044] The film-forming aid is a dodecyl alcohol ester, specifically Eastman TEXANOL dodecyl alcohol ester.

[0045] The antifreeze is ethylene glycol.

[0046] pH adjuster, model number Dow AMP-95.

[0047] The water used in the embodiments of this invention is deionized water.

[0048] Example 1

[0049] A self-cleaning water-based exterior wall waterproof coating, wherein the self-cleaning water-based exterior wall waterproof coating comprises the following components by mass fraction:

[0050]

[0051]

[0052] The preparation method of the self-cleaning water-based exterior wall waterproof coating includes the following steps:

[0053] S1. Titanium dioxide was calcined at 500℃ for 1 hour, then added to a sufficient amount of 2 mol / L sodium hydroxide solution, sonicated for 1 hour, washed and dried to obtain the intermediate product;

[0054] S2. Using ethanol as a solvent, the intermediate product and dodecyloxybenzoic acid in a molar ratio of 1:4 were mixed and ultrasonically reacted at 70°C for 10 hours. After filtration, washing, and drying, the modified titanium dioxide was obtained.

[0055] S3. Add the cellulose thickener to water and stir at 600 rpm for 5 minutes. Then, add the wetting agent, dispersant, film-forming aid, defoamer, antifreeze, and pH adjuster in the above mass fractions and stir at 700 rpm for 10 minutes. Then, add the modified titanium dioxide, heavy calcium carbonate, rutile titanium dioxide, and superhydrophobic talc in the above mass fractions, increase the speed to 1500 rpm, and stir and disperse for 20 minutes until the fineness is less than 60 μm.

[0056] S4. Reduce the rotation speed to 700 rpm, add silicone acrylic emulsion, organosilicon resin emulsion and bactericide in sequence according to the above mass fraction, disperse for 10 min, and finally add polyurethane thickener. After stirring and dispersing for 15 min, the viscosity is tested at 25℃ and is 98.5 KU, thus obtaining the self-cleaning water-based exterior wall waterproof coating.

[0057] Example 2

[0058] A self-cleaning water-based exterior wall waterproof coating, wherein the self-cleaning water-based exterior wall waterproof coating comprises the following components by mass fraction:

[0059]

[0060]

[0061] The preparation method of the self-cleaning water-based exterior wall waterproof coating is the same as that in Example 1, except that the mass fractions of the above-mentioned components are changed.

[0062] Example 3

[0063] A self-cleaning water-based exterior wall waterproof coating, wherein the self-cleaning water-based exterior wall waterproof coating comprises the following components by mass fraction:

[0064]

[0065] The preparation method of the self-cleaning water-based exterior wall waterproof coating is the same as that in Example 1, except that the mass fractions of the above-mentioned components are changed.

[0066] Comparative Example 1

[0067] The difference between this comparative example and Example 1 is that the superhydrophobic talc powder is replaced with an equal mass fraction of ordinary talc powder (Heshan Chemical CMS-666), while the other components and preparation methods are the same as in Example 1.

[0068] Comparative Example 2

[0069] The difference between this comparative example and Example 1 is that the silicone resin emulsion is replaced with an equal mass fraction of hydrophobic agent (Ceramic V15), while the other components and preparation methods are the same as in Example 1.

[0070] Comparative Example 3

[0071] The difference between this comparative example and Example 1 is that the silicone-acrylic emulsion is replaced with an equal mass fraction of BADF-998KD, while the other components and preparation methods are the same as in Example 1.

[0072] Comparative Example 4

[0073] The difference between this comparative example and Example 1 is that the modified titanium dioxide is replaced with an equal mass fraction of unmodified titanium dioxide, while the other components and preparation methods are the same as in Example 1.

[0074] Test case

[0075] Test method: The self-cleaning water-based exterior wall waterproof coatings prepared in Examples 1-3 and Comparative Examples 1-4 were tested for key performance according to standards such as GB / T9755-2014 Synthetic Resin Emulsion Exterior Wall Coatings. The results are shown in Tables 1 and 2.

[0076] Table 1 Comparison of Performance Test Results of Examples 1-3

[0077]

[0078]

[0079] The performance test results of the coatings prepared in Example 1 and Comparative Examples 1-4 are shown in Table 2.

[0080] Table 2 Comparison of test results between Example 1 and Comparative Examples 1-4

[0081]

[0082]

[0083] The experimental data above show that the self-cleaning water-based exterior wall waterproof coatings prepared in Examples 1-3 have good performance, with basically no abnormalities in workability (comparative ratio > 0.93), greater than 10,000 scrub resistance, no abnormalities in low-temperature storage, stain resistance < 10%, and low water permeability. Furthermore, after being stored at 55℃ for 3 months, raindrops on the paint film rolled off in a circular pattern. In contrast, in Comparative Examples 1-4, the silicone resin emulsion, silicone-acrylic emulsion, superhydrophobic talc, and modified titanium dioxide were replaced, respectively. The hydrophobicity and the long-term hydrophobic effect after a period of storage were not as good as in the examples. This fully demonstrates that the synergistic effect among modified titanium dioxide, silicone resin emulsion, silicone-acrylic emulsion, and superhydrophobic talc is the key to achieving the self-cleaning and waterproofing effects of the coating.

[0084] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0085] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A self-cleaning water-based exterior wall waterproof coating, characterized in that, The self-cleaning water-based exterior wall waterproof coating comprises the following components by mass fraction: The modified titanium dioxide is dodecyloxybenzoic acid-modified titanium dioxide. The preparation method of the self-cleaning water-based exterior waterproof coating includes the following steps: S1, calcining titanium dioxide and adding it to sodium hydroxide solution, then ultrasonically treating it to obtain an intermediate product; S2, using ethanol as a solvent, mixing the intermediate product and dodecyloxybenzoic acid, and ultrasonically heating the mixture to obtain modified titanium dioxide; S3, adding some additives to water, stirring, and then adding modified titanium dioxide, heavy calcium carbonate, rutile titanium dioxide, and superhydrophobic talc powder, stirring and dispersing to a certain fineness; S4, adding silicone acrylic emulsion, silicone resin emulsion, and the remaining additives, stirring and dispersing until the viscosity is qualified to obtain the self-cleaning water-based exterior waterproof coating.

2. The self-cleaning water-based exterior wall waterproof coating according to claim 1, characterized in that, The superhydrophobic talc powder has a fineness of ≤4.5μm and a SiO2 content of ≥59%.

3. The self-cleaning water-based exterior wall waterproof coating according to claim 1, characterized in that, The additives include dispersants, wetting agents, defoamers, thickeners, bactericides, film-forming aids, antifreeze agents, and pH adjusters.

4. The self-cleaning water-based exterior wall waterproof coating according to claim 1, characterized in that, The roasting temperature described in S1 is 400-600℃.

5. The self-cleaning water-based exterior wall waterproof coating according to claim 1, characterized in that, The sodium hydroxide solution concentration mentioned in S1 is 1-3 mol / L.

6. The self-cleaning water-based exterior wall waterproof coating according to claim 1, characterized in that, The molar ratio of the intermediate product and dodecyloxybenzoic acid in S2 is 1:4 to 1:

6.

7. The self-cleaning water-based exterior wall waterproof coating according to claim 1, characterized in that, The ultrasonic heating reaction described in S2 has a temperature of 60-100℃ and a duration of 5-20h.

8. The self-cleaning water-based exterior wall waterproof coating according to claim 1, characterized in that, The fineness of S3 is less than 60μm.

9. The self-cleaning water-based exterior wall waterproof coating according to claim 1, characterized in that, The viscosity of S4 is 95-105 KU.

Images