Concrete water-based oleophobic coating and preparation method thereof

Abstract

The invention provides a concrete water-based oleophobic coating and a preparation method thereof. The concrete water-based oleophobic coating comprises the following raw materials in percentage by mass: 20-50% of film-forming resin, 20-50% of a water-based oleophobic agent, 10-30% of a water- 1%-10% of hydrogen-containing polysiloxane; 0.1%-5% of an elastic fluorocarbon nano material; 1%-10% of a functional nano filler; 0.5%-3% of a surfactant; 0.05%-1% of a catalytic cross-linking agent; the balance of dispersion medium; the elastic fluorocarbon nano material is a carbon fluoride nano spring or a carbon fluoride nano coil; the balance of dispersion medium; the preparation method is the preparation method of the coating. The hydrogen-containing polysiloxane in the raw materials of the coating solves the problem of interface adhesion, the elastic fluorocarbon nanomaterial solves the problem of body tolerance, and the hydrogen-containing polysiloxane and the elastic fluorocarbon nanomaterial are combined to achieve a synergistic effect, so that the comprehensive properties such as adhesion, impact resistance and temperature change resistance of the coating are qualitatively improved.

Description

Technical Field

[0001] This application relates to the field of concrete coating technology, and in particular to a water-based oleophobic coating for concrete and its preparation method. Background Technology

[0002] Concrete, as a widely used building material, is extensively applied in construction, roads, bridges, and other fields due to its excellent mechanical properties and economy. However, concrete's porous structure makes it highly susceptible to erosion from water, oil, and chemicals during long-term use, leading to surface contamination, reduced strength, and decreased durability, affecting its appearance and service life. Traditional concrete protection measures, such as water-repellent agents or ordinary coatings, primarily focus on improving the concrete's waterproof performance, typically by reducing surface energy or filling pores to prevent water penetration. However, these traditional methods are often ineffective against oil stains, especially non-polar liquids such as engine oil, cooking oil, and asphalt. Oil stains can easily adhere to and penetrate the concrete surface, even forming stubborn stains that are difficult to remove, rendering concrete ineffective against oil erosion.

[0003] The application of existing oleophobic coatings on concrete substrates faces two major technical bottlenecks: first, the adhesion between the coating and the concrete substrate is insufficient, and it is prone to peeling under the stress caused by changes in temperature and humidity; second, the coating has poor durability and is difficult to withstand wear and tear during long-term use.

[0004] To address these issues, the present invention provides a water-based oleophobic coating for concrete and a method for preparing it. Summary of the Invention

[0005] The purpose of this application is to provide a water-based oleophobic coating for concrete and a method for preparing it, so as to solve or alleviate the problems existing in the prior art.

[0006] To achieve the above objectives, this application provides the following technical solution: A water-based oleophobic coating for concrete comprises the following raw materials in weight percentages: Film-forming resin 20%-50%; hydrogen-containing polysiloxane 1%-10%; elastic fluorocarbon nanomaterial 0.1%-5%; functional nanofiller 1%-10%; surfactant 0.5%-3%; catalytic crosslinking agent 0.05%-1%; dispersion medium as balance; the elastic fluorocarbon nanomaterial is a fluorinated carbon nanospring or a fluorinated carbon nanocoil; dispersion medium as balance.

[0007] Furthermore, the dispersion medium is deionized water or a mixture of alcohol solvent and water; the alcohol solvent is selected from one or more of ethanol, isopropanol, ethylene glycol, and propylene glycol.

[0008] Furthermore, the film-forming resin is selected from one or more of the following: silicone-modified acrylic emulsion, epoxy-modified acrylic emulsion, polyurethane-modified acrylic emulsion, pure acrylic emulsion, and vinyl acrylic copolymer emulsion; the solid content of the film-forming resin is 40%-50% to ensure that the coating has sufficient film-forming material to form a dense protective layer; the glass transition temperature (T0) is... g The temperature range is -10℃ to 30℃. g Within this range, the hardness and flexibility of the coating can be balanced. g Excessive temperature can increase the brittleness of the coating, making it prone to cracking when microcracks appear in the concrete substrate due to temperature changes or loads; T g If the temperature is too low, the coating will be too soft and easily attract contaminants. The T value of this invention... g The range ensures that the coating remains intact under dynamic deformation of concrete and synergizes with subsequent elastic nanomaterials.

[0009] Furthermore, the hydrogen-containing polysiloxane is selected from one or more of terminal hydrogen-containing silicone oil, side-containing hydrogen-containing silicone oil, and hydrogen-containing MQ resin; the hydrogen content of the hydrogen-containing polysiloxane is 0.1%-1.6%, and the viscosity is 100-3000 mPa·s. The hydrogen-containing polysiloxane is one of the core components for achieving strong adhesion in coatings. Its active Si-H bonds can undergo dehydrogenation reactions with the abundant silanol groups (-Si-OH) on the concrete surface under the action of a catalytic crosslinking agent, forming strong Si-O-Si covalent bonds, thereby achieving chemical bonding between the coating and the substrate, fundamentally solving the problem of poor physical adhesion. Control of the hydrogen content and viscosity ensures its reactivity and dispersion and migration capabilities in the system.

[0010] Furthermore, the elastic fluorocarbon nanomaterials are prepared by the following method: using transition metals such as ferrocene and cobalt acetylacetonate as catalysts, carbon nanosprings / carbon nanocoils with a three-dimensional helical structure are grown in a quartz tube furnace at 600-800°C in an argon atmosphere via chemical vapor deposition. Acetylene or ethylene is used as the carbon source. Subsequently, the obtained carbon nanomaterials are placed in a corrosion-resistant fluorination reactor, and a mixture of fluorine gas and an inert gas (such as nitrogen) (fluorine gas fraction 10%-30%) is introduced at 200-400°C, or carbon tetrafluoride is used as the fluorinating agent under similar conditions for gas-phase fluorination treatment for 1-3 hours. After the reaction, the mixture is cooled to room temperature under an inert atmosphere to obtain fluorinated carbon nanosprings / fluorinated carbon nanocoils.

[0011] The elastic fluorocarbon nanomaterials provide the coating with excellent durability. The extremely low surface energy of the fluorinated layer significantly enhances oleophobicity. Their unique three-dimensional helical elastic structure allows them to combine with the film-forming resin within the coating to form a microscopic spring network. When the coating is subjected to external stress (such as friction, impact, or thermal stress), this network effectively absorbs and disperses stress through its elastic deformation, preventing crack propagation and greatly improving the coating's impact resistance and flexibility. This is fundamentally different from traditional rigid fluorocarbon nanoparticles. Traditional rigid fluorocarbon nanoparticles are mostly distributed in a discrete point pattern in the coating, making it difficult to adapt to coating deformation under stress. They are prone to interfacial delamination with the film-forming resin, leading to coating peeling and powdering.

[0012] Preferably, the fluorine content in the elastic fluorocarbon nanomaterial is ≥10wt%, and the maximum size is 50-500nm; in the raw material for water-based oleophobic coating of concrete, the mass percentage of the elastic fluorocarbon nanomaterial is 1.5%-2.5%, and the mass percentage of hydrogen-containing polysiloxane is 3%-8%.

[0013] Furthermore, the functional nanofiller serves to further reduce the surface energy of the coating, enhance the oleophobic effect, and simultaneously fill the microstructure of the coating, improving its density and mechanical strength. Its type is selected from one or more of the following nano-oxides: fluorinated nano-silica, fluorinated nano-alumina, fluorinated nano-titanium dioxide, and surface-modified nano-oxides with perfluorosilane coupling agents. The functional nanofiller has a particle size of 10-100 nm and a fluorine content ≥8 wt%.

[0014] Furthermore, the surfactant includes an emulsifier and a dispersant; the emulsifier is selected from nonionic emulsifiers and / or anionic emulsifiers; the nonionic emulsifier is selected from one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and sorbitan fatty acid ester polyoxyethylene ether; the anionic emulsifier is selected from one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and secondary alkyl sulfonate; the dispersant is selected from one or more of polycarboxylate dispersants and modified polyacrylate dispersants.

[0015] Furthermore, the catalytic crosslinking agent is a platinum-based catalyst or a rhodium-based catalyst capable of catalyzing hydrosilylation reactions; the platinum-based catalyst is selected from one or more of isopropanol chloroplatinate solution, platinum-vinylsiloxane complex, and platinum-olefin complex; the platinum metal in the catalytic crosslinking agent accounts for 10-1000 ppm of the total mass of the raw material for the water-based oleophobic coating of concrete.

[0016] Furthermore, the raw materials of the water-based oleophobic coating for concrete also include additives, which are selected from one or more of leveling agents, defoamers, thickeners, wetting agents, ultraviolet absorbers, light stabilizers, preservatives and pigments. The total content of the additives is 0-8% of the total weight of the raw materials of the water-based oleophobic coating for concrete.

[0017] The surfactants, catalytic crosslinking agents, dispersion media, and additives together ensure the water-based properties, stability, and overall performance of the coating system.

[0018] This invention also proposes a method for preparing the aforementioned water-based oleophobic coating for concrete, characterized by comprising the following steps: Step 1: Pre-emulsification of hydrogen-containing polysiloxane: Hydrogen-containing polysiloxane, a portion of surfactant (mainly emulsifier), and a portion of aqueous phase are mixed at a mass ratio of 1:(0.15~0.35):(1.5~3.0), and a pre-emulsion is prepared by high-speed shearing at a speed of 4500-5500 rpm for 12-18 minutes to ensure that the hydrophobic hydrogen-containing polysiloxane is uniformly and stably dispersed in the aqueous phase. Step 2, Nanomaterial Pretreatment: The elastic fluorocarbon nanomaterials and surfactants (mainly dispersants) are mixed in a dispersion medium solution at a mass ratio of 1:(0.5~1.5):(15~25), and treated with ultrasonic power of 500-800W for 25-35 minutes to obtain a uniform and stable dispersion. Functional nanofillers and surfactants (mainly dispersants) were mixed in a dispersion medium at a mass ratio of 1:(0.1~0.3):(8~15), and then treated with ultrasonic power of 500-800W for 25-35 minutes to obtain a uniform and stable dispersion. This step aims to break up the agglomeration of nanoparticles, form a stable dispersion, and avoid defects when introducing coatings later. Step 3, Stepwise Composite Reaction: The pre-emulsion obtained in Step 1 is mixed with a portion (40%-60% of the total mass of film-forming resin) of the film-forming resin. A catalytic crosslinking agent is added, and the mixture is pre-reacted at 45-55℃ for 25-35 minutes to allow the hydrogen-containing polysiloxane portion to undergo initial crosslinking with the film-forming resin system, forming a stable network prototype. Subsequently, the functional nanofiller dispersion and the elastic fluorocarbon nanomaterial dispersion obtained in Step 2 are added sequentially and mixed thoroughly. The stepwise addition avoids the competitive reactions and uneven dispersion of nanomaterials that may result from mixing all components at once. Step 4, Post-treatment: Add the remaining film-forming resin, remaining surfactant, and other additives (such as leveling agents, defoamers, etc.), adjust the pH to a weakly alkaline environment of 7.5-8.5 with ammonia water, and continuously stir and mature at 45-55℃ for 2.5-3 hours to make the cross-linking reaction more complete and the system more stable; finally, filter through a 250-300 mesh filter to remove any possible small amount of agglomerated particles and obtain a uniform and stable coating composition.

[0019] The technical solution of this application has the following beneficial effects: The hydrogen-containing polysiloxane in the coating raw material of this application solves the interfacial adhesion problem, while the elastic fluorocarbon nanomaterial solves the bulk durability problem. The synergistic effect of the two results in a qualitative improvement in the overall performance of the coating, including adhesion, impact resistance, and temperature change resistance. This invention achieves a leap from physical adsorption to chemical bonding by forming strong Si-O-Si covalent bonds between the Si-H bonds of the hydrogen-containing polysiloxane and the hydroxyl groups on the concrete surface, significantly improving the adhesion of the coating to the concrete surface. The elastic fluorocarbon nanomaterial and functional nanofillers jointly construct a low surface energy micro / nano structure, with hydrophobic and oleophobic properties far exceeding those of traditional protective coatings. The elastic fluorocarbon nanomaterial forms a three-dimensional elastic network within the coating, effectively dispersing and absorbing mechanical stress, resulting in excellent durability and mechanical properties for the coating of this application. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. Wherein: Figure 1 This is a photograph of the contact angle test of hexadecane (oil droplets) on the surface of the test block in Example 1 of the present invention.

[0021] Figure 2 This is a photograph illustrating the hydrophobic oil transport properties of the specimen surface in Embodiment 1 of the present invention. Detailed Implementation

[0022] The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] Example 1 A water-based oleophobic coating for concrete comprises the following raw materials in weight percentages: Film-forming resin 35%; hydrogen-containing polysiloxane 5%; elastic fluorocarbon nanomaterials 1.5%; functional nanofillers 5%; surfactants 2.2%; catalytic crosslinking agents 0.3%; water 51%; The film-forming resin is an organosilicon-modified acrylic emulsion with a solid content of 45%. g=15℃; the hydrogen-containing polysiloxane uses side-containing hydrogen silicone oil with a hydrogen content of 1.2% and a viscosity of 1500 mPa·s; the elastic fluorocarbon nanomaterial uses fluorinated carbon nanosprings with a spiral diameter of 100 nm and a fluorine content of 12 wt%; the functional nanofiller uses fluorinated nano silica particles with a particle size of 30 nm and a fluorine content of 10 wt%; the surfactant consists of 1.0% alkylphenol polyoxyethylene ether (OP-10), 0.2% sodium dodecyl sulfate (SDS), and 1% polycarboxylate dispersant; the catalytic crosslinking agent is isopropanol chloroplatinate solution with a platinum content of 1000 ppm.

[0024] Example 1 is a balanced formulation, which combines organosilicon-modified resin and side-containing hydrogen silicone oil, taking into account oleophobicity, flexibility and adhesion, and is suitable for general concrete protection scenarios.

[0025] A method for preparing a water-based oleophobic coating for concrete includes the following steps: Step 1: Pre-emulsification of hydrogen-containing polysiloxane: Hydrogen-containing polysiloxane, emulsifier, and a portion of the dispersion medium are mixed at a mass ratio of 1:0.3:2 and emulsified under high-speed shear at 5000 rpm for 15 minutes to obtain a stable pre-emulsion. Elastic fluorocarbon nanomaterials and functional nanofillers are then added separately to an aqueous solution containing 0.5% dispersant and ultrasonically treated at 600W for 30 minutes to form a uniform dispersion.

[0026] Step 2: Nanomaterial Pretreatment: Functional nanofiller matrix powder and perfluorooctyltriethoxysilane (PFOTES) (surfactant) were dispersed in anhydrous ethanol to form a 5 wt% suspension. The suspension was stirred at 60°C for 4 hours. The mass ratio of functional nanofiller matrix powder, PFOTES (surfactant), and water was 1:1.5:10. After the reaction, the mixture was centrifuged, washed three times with ethanol, and vacuum dried at 80°C for 2 hours to obtain the functional nanofiller with a fluorine content of 10 wt%. Elastic fluorocarbon nanomaterials and surfactants (mainly dispersants) are mixed in a dispersion medium solution at a mass ratio of 1:1:20 and treated with ultrasonic power of 500-800W for 25-35 minutes to obtain a uniform and stable dispersion. Steps one and two are independent and can be performed in any order.

[0027] Step 3, Stepwise Composite Reaction: The pre-emulsion and half of the film-forming resin (half of the film-forming resin accounts for 17.5% of the total formulation mass) are mixed in a reactor. A catalytic crosslinking agent is added, and the mixture is pre-reacted at 50°C and a stirring speed of 1000 rpm for 30 minutes to allow the hydrogen-containing polysiloxane portion to undergo preliminary crosslinking with the film-forming resin system, forming a stable network prototype. Then, the functional nanofiller dispersion and the elastic fluorocarbon nanomaterial dispersion are added sequentially, and the mixture is stirred for 15 minutes after each addition to ensure uniform mixing.

[0028] Step 4, Post-treatment: Add the remaining half of the film-forming resin, the remaining surfactant and other additives (such as leveling agents, defoamers, etc.), adjust the pH to 8.0 with ammonia, and continue stirring and maturing at 50°C for 3 hours. Finally, filter through a 280-mesh filter to obtain the coating composition of this embodiment.

[0029] Example 2 Compared with Example 1, Example 2 differs in the selection of raw materials and the content of components.

[0030] A water-based oleophobic coating for concrete comprises the following raw materials in weight percentages: Film-forming resin 32%; hydrogen-containing polysiloxane 6%; elastic fluorocarbon nanomaterials 2%; functional nanofillers 6%; surfactant 2.7%; catalytic crosslinking agent 0.4%; water 50.9%; The film-forming resin is an epoxy-modified acrylic emulsion with a solid content of 48%. g =25℃; the hydrogen-containing polysiloxane uses end-hydrogen silicone oil with a hydrogen content of 0.8% and a viscosity of 800 mPa·s; the elastic fluorocarbon nanomaterial uses fluorinated carbon nanotube coils with a diameter of 80 nm and a fluorine content of 15 wt%; the functional nanofiller uses fluorinated nano-alumina with a particle size of 25 nm and a fluorine content of 9 wt%; the surfactant consists of 1.2% fatty alcohol polyoxyethylene ether (AEO-9), 0.3% sodium dodecylbenzenesulfonate (SDBS), and 1.2% modified polyacrylate dispersant; the catalytic crosslinking agent is a Karstedt platinum catalyst with a platinum content of 3000 ppm.

[0031] The coating preparation method in Example 2 is the same as that in Example 1.

[0032] Example 2 is a highly oleophobic formulation, featuring a high-fluorine-content nanocoil and a highly efficient Karstedt catalyst, exhibiting outstanding oleophobic properties. At the same time, the epoxy-modified resin enhances the coating hardness, making it suitable for scenarios with severe oil pollution, such as gas station floors.

[0033] Example 3 A water-based oleophobic coating for concrete comprises the following raw materials in weight percentages: Film-forming resin 38%; hydrogen-containing polysiloxane 3%; elastic fluorocarbon nanomaterials 1%; functional nanofillers 4%; surfactants 2.6%; catalytic crosslinking agents 0.2%; water 51.2%. The film-forming resin is made of pure acrylic emulsion with a solid content of 48%. g=5℃; the hydrogen-containing polysiloxane uses hydrogen-containing MQ resin with a hydrogen content of 1.0%; the elastic fluorocarbon nanomaterial uses fluorinated carbon nanosprings with a spiral diameter of 120nm and a fluorine content of 11wt%; the functional nanofiller uses fluorinated nano silica particles with a particle size of 30nm and a fluorine content of 10wt%; the surfactant consists of 1.8% composite emulsifier (OP-10 and AEO-9 are compounded in a mass ratio of 1:2) and 0.8% polycarboxylate dispersant; the catalytic crosslinking agent is isopropanol chloroplatinate solution with a platinum content of 1000ppm.

[0034] The coating preparation method in Example 3 is the same as that in Example 1.

[0035] Example 3 is a high-adhesion, flexible, directional formulation, using a high-content pure acrylic emulsion (low T). g It contains hydrogen-containing MQ resin, resulting in a coating with excellent flexibility and strong adhesion. It is suitable for concrete structures that are susceptible to vibration or temperature differences, such as bridges and outdoor pavements. Its oleophobic properties are at a basic level among the three.

[0036] Comparative Example 1 Comparative Example 1, compared to Example 1, does not contain hydrogen-containing polysiloxanes, and its 5% mass is supplemented by silicone-modified acrylic emulsion (film-forming resin), comprising the following raw materials by mass percentage: Film-forming resin 40%; hydrogen-containing polysiloxane 0%; elastic fluorocarbon nanomaterials (fluorinated carbon nanosprings) 1.5%; functional nanofillers (fluorinated nano silica) 5%; surfactants (1.0% OP-10 + 0.2% SDS + 1.0% polycarboxylate dispersant) 2.2%; catalytic crosslinking agent (isopropanol chloroplatinic acid solution) 0.3%; water 51%.

[0037] Comparative Example 2 Compared to Example 1, Comparative Example 2 does not contain elastic fluorocarbon nanomaterials; 1.5% of its mass is made up by functional nanofillers, comprising the following raw materials by mass percentage: Film-forming resin: 35%; hydrogen-containing polysiloxane: 5%; elastic fluorocarbon nanomaterials: 0%; functional nanofillers: 6.5%; surfactants: 2.2%; catalytic crosslinking agents: 0.3%; water: 51%.

[0038] Comparative Example 3 Compared to Example 1, Comparative Example 3 did not contain elastic fluorocarbon nanomaterials; its 1.5% mass was supplemented by ordinary fluorocarbon powder (non-elastic structure), comprising the following raw materials by mass percentage: Film-forming resin: 35%; Hydrogen-containing polysiloxane: 5%; Elastic fluorocarbon nanomaterials: 0%; Functional nanofillers: 5%; Ordinary fluorocarbon powder: 1.5%; Surfactant: 2.2%; Catalytic crosslinking agent: 0.3%; Water: 51%; Ordinary fluorinated carbon powder has a particle size of 100-500nm and a fluorine content of ≥10wt%.

[0039] Comparative Example 4 The coating used is a commercially available solvent-based fluorocarbon resin, model wjf-67, manufactured by Anhui Liuyuan New Material Technology Co., Ltd.

[0040] Comparative Example 5 Compared with Example 1, Comparative Example 5 has the same raw material components. The difference is that in the preparation steps, a traditional one-time feeding process is adopted. All components (except catalyst) are mixed at one time and then the catalyst is added to react. No stepwise compounding reaction is carried out.

[0041] Comparative Example 6 Compared with Example 1, Comparative Example 6 has the same raw material components. The difference is that in step one of the preparation steps, the pre-emulsification speed is 3000 rpm, resulting in poor emulsion stability.

[0042] The coatings prepared in the above examples and comparative examples were applied to concrete test blocks according to standard methods. The test blocks were 70.7mm × 70.7mm × 70.7mm in size and were applied by brushing. The coating thickness was (60±5)μm (dry film thickness). After curing, the performance was tested according to national standards. The test methods are as follows: contact angle measurement refers to "GB / T 30693-2014 Measurement of contact angle between plastic film and water"; adhesion test refers to "GB / T 9286-1998 Cross-cut test of paint and varnish film"; tensile strength test refers to "GB / T 5210-2006 Adhesion test of paint and varnish by pull-out method"; alkali resistance test refers to "GB / T9265-2009 Determination of alkali resistance of architectural coatings"; impact resistance test refers to "GB / T 1732-1993 Test method for impact resistance of paint film"; temperature change resistance test (with -20℃ / 2h→60℃ / 2h as one cycle) refers to "GB / T 9154-2006 Determination of resistance to liquid media of paint and varnish".

[0043] The 30-day alkali resistance test results were as follows: Examples 1-3: no change in coating; Comparative Examples 1-3: slight loss of gloss in coating; Comparative Example 4: blistering in coating; Comparative Example 5: significant loss of gloss in coating; Comparative Example 6: slight loss of gloss in coating. The 10-cycle temperature resistance test results were as follows: Examples 1-3: no change in coating; Comparative Example 1: blistering in coating; Comparative Example 2: microcracks appearing in coating; Comparative Example 3: peeling off in coating; Comparative Example 4: cracking in coating; Comparative Examples 5-6: peeling off in coating.

[0044] Other test results for each embodiment and comparative example are shown in Table 1. Figure 1 Photographs showing the contact angle test of hexadecane (oil droplets) on the surface of the test block in Example 1. Figure 2This example demonstrates the hydrophobic and oil-transporting properties of the specimen surface in Example 1. The droplets near the center of the specimen surface are oil droplets (hexadecane), while the droplets near the edges are water droplets.

[0045] Table 1 Test results of the examples and comparative examples

[0046] The test results above show that the contact angle of hexadecane in all embodiments exceeds 125°, which is higher than that in the comparative example, and meets the oleophobic standard. This proves that the introduction of hydrogen-containing polysiloxane and elastic fluorocarbon nanomaterials and their synergistic effect effectively construct a stable low surface energy surface.

[0047] All embodiments achieved an adhesion grade of 0 and a tensile strength exceeding 3.0 MPa, significantly superior to the comparative example. This strongly demonstrates that the key to achieving ultra-strong adhesion lies in the formation of Si-O-Si covalent bonds between hydrogen-containing polysiloxane and the hydroxyl groups on the concrete surface via Si-H bonds. Comparative Example 2's test results show that while the traditional method of using hydrogen-containing polysiloxane and adding functional nanofillers can achieve certain adhesion and tensile strength, the coating's brittleness increases significantly, its impact resistance is poor, and the improvement in oleophobic properties is limited. In contrast, Example 1 of this invention, by introducing elastic fluorocarbon nanomaterials, endows the coating with excellent toughness and impact resistance while maintaining extremely strong adhesion, and significantly improves oleophobicity. This demonstrates an unexpected synergistic effect between the elastic fluorocarbon nanomaterials and the hydrogen-containing polysiloxane, jointly achieving a qualitative leap in the overall performance of the coating.

[0048] Durability: All embodiments passed rigorous alkali resistance and temperature change resistance tests, demonstrating excellent durability. This illustrates that the three-dimensional network structure of the fluorocarbon nanomaterials effectively disperses stress, thanks to the strong chemical bonding interfaces and the buffering effect of the elastic nanonetwork on internal stress caused by environmental changes.

[0049] Significant synergistic effect: Examples 1-3 significantly outperformed Comparative Examples 1-6 in all performance indicators, demonstrating a clear synergistic enhancement effect between hydrogen-containing polysiloxane and elastic fluorocarbon nanomaterials. Particularly in terms of hydrophobicity and tensile strength, the performance improvements of the examples far exceeded the simple summation of the effects of the individual components.

[0050] VOC refers to the weight of volatile organic compounds in 1 liter of paint after removing water. The VOC content of all examples is less than 50g / L, which is far lower than that of traditional solvent-based paints and meets environmental protection requirements.

[0051] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A water-based oleophobic coating for concrete, characterized in that: The raw materials include the following percentages by weight: Film-forming resin 20%-50%; hydrogen-containing polysiloxane 1%-10%; elastic fluorocarbon nanomaterial 0.1%-5%; functional nanofiller 1%-10%; surfactant 0.5%-3%; catalytic crosslinking agent 0.05%-1%; dispersion medium as balance; the elastic fluorocarbon nanomaterial is a fluorinated carbon nanospring or a fluorinated carbon nanocoil; dispersion medium as balance.

2. The water-based oleophobic coating for concrete according to claim 1, characterized in that: The film-forming resin is selected from one or more of the following: silicone-modified acrylic emulsion, epoxy-modified acrylic emulsion, polyurethane-modified acrylic emulsion, pure acrylic emulsion, and vinyl acrylic copolymer emulsion; the solid content of the film-forming resin is 40%-50%, and the glass transition temperature is -10℃ to 30℃.

3. The water-based oleophobic coating for concrete according to claim 1, characterized in that: The hydrogen-containing polysiloxane is selected from one or more of end-hydrogen-containing silicone oil, side-hydrogen-containing silicone oil, and hydrogen-containing MQ resin; the hydrogen content of the hydrogen-containing polysiloxane is 0.1%-1.6%, and the viscosity is 100-3000 mPa·s.

4. The water-based oleophobic coating for concrete according to claim 1, characterized in that: The elastic fluorocarbon nanomaterials are prepared by the following method: using a transition metal as a catalyst, carbon nanosprings or carbon nanocoils are synthesized by chemical vapor deposition, followed by gas-phase fluorination treatment in a fluorine or carbon tetrafluoride atmosphere at a temperature of 200-400℃ for 1-3 hours to obtain fluorinated carbon nanosprings or fluorinated carbon nanocoils.

5. The water-based oleophobic coating for concrete according to claim 1, characterized in that: The elastic fluorocarbon nanomaterial has a fluorine content of ≥10wt% and a maximum size of 50-500nm; in the raw material for water-based oleophobic coatings for concrete, the elastic fluorocarbon nanomaterial has a mass percentage of 1.5%-2.5%, and the hydrogen-containing polysiloxane has a mass percentage of 3%-8%.

6. The water-based oleophobic coating for concrete according to claim 1, characterized in that: The functional nanofiller is selected from one or more of fluorinated nano silica, fluorinated nano alumina, fluorinated nano titanium dioxide, and nano oxides modified with perfluorosilane coupling agent; the particle size of the functional nanofiller is 10-100 nm, and the fluorine content is ≥8 wt%.

7. The water-based oleophobic coating for concrete according to claim 1, characterized in that: The surfactant includes an emulsifier and a dispersant; the emulsifier is selected from nonionic emulsifiers and / or anionic emulsifiers; the nonionic emulsifier is selected from one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and sorbitan fatty acid ester polyoxyethylene ether; the anionic emulsifier is selected from one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and secondary alkyl sulfonate; the dispersant is selected from one or more of polycarboxylate dispersants and modified polyacrylate dispersants.

8. The water-based oleophobic coating for concrete according to claim 1, characterized in that: The catalytic crosslinking agent is a platinum-based or rhodium-based catalyst capable of catalyzing hydrosilylation reactions; the platinum-based catalyst is selected from one or more of isopropanol chloroplatinate solution, platinum-vinylsiloxane complex, and platinum-olefin complex; the platinum metal in the catalytic crosslinking agent accounts for 10-1000 ppm of the total mass of the raw material for water-based oleophobic coatings for concrete.

9. The water-based oleophobic coating for concrete according to claim 1, characterized in that: The raw materials of the water-based oleophobic coating for concrete also include additives, which are selected from one or more of leveling agents, defoamers, thickeners, wetting agents, ultraviolet absorbers, light stabilizers, preservatives and pigments. The total content of the additives is 0-8% of the total weight of the raw materials of the water-based oleophobic coating for concrete.

10. A method for preparing a water-based oleophobic coating for concrete as described in any one of claims 1 to 9, characterized in that: Includes the following steps: Step 1: Pre-emulsification of hydrogen-containing polysiloxane: Hydrogen-containing polysiloxane and a portion of surfactant are mixed in an aqueous phase and a pre-emulsion is prepared by high-speed shearing at a speed of 4500-5500 rpm for 12-18 minutes. Step 2, Nanomaterial Pretreatment: Elastic fluorocarbon nanomaterials and functional nanofillers are ultrasonically dispersed in a dispersion medium solution containing a portion of surfactant. The ultrasonic power is 500-800W and the treatment time is 25-35 minutes, respectively, to obtain elastic fluorocarbon nanomaterial dispersion and functional nanofiller dispersion. Step 3, Stepwise Composite Reaction: Mix the pre-emulsion obtained in Step 1 with a portion of the film-forming resin, add a catalytic crosslinking agent, and pre-react at 45-55℃ for 25-35 minutes; then add the functional nanofiller dispersion and the elastic fluorocarbon nanomaterial dispersion obtained in Step 2 in sequence, and mix thoroughly. Step 4, Post-treatment: Add the remaining film-forming resin and the remaining surfactant, adjust the pH to 7.5-8.5, and continue stirring and maturing at 45-55℃ for 2.5-3 hours. Finally, filter through a 250-300 mesh filter to obtain the coating composition.

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