A method for preparing a superhydrophobic, abrasion-resistant waterborne strippable coating

Abstract

The application provides a preparation method of super-hydrophobic, wear-resistant water-based strippable paint, comprising the following steps: preparing a water-based polyurethane prepolymer; preparing a water-based polyurethane dispersion by using an anionic hydrophilic group-containing aminoalkyl sulfonate as a chain extender; mixing the water-based polyurethane dispersion with modified fillers, a water-based defoaming agent, a water-based polyether siloxane leveling agent, a water-based acetylenic diol wetting agent, a water-based lotus hydrophobic agent, a water-based film-forming aid, a water-based associated polyurethane thickening agent and deionized water, and then adding a pH regulator to adjust the pH to obtain super-hydrophobic surface water-based strippable paint; the modified fillers are polymer-coated SiO2 / carbon nanotube composite fillers, and the coating layer is composed of a polydimethyl siloxane layer and a polycaprolactone / epoxy resin layer from inside to outside. The paint prepared by the application has good strippable effect, excellent hydrophobicity, excellent wear resistance and certain self-cleaning performance.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a method for preparing a superhydrophobic, wear-resistant, water-based peelable coating. Background Technology

[0002] Peelable coatings are a special type of protective coating applied to the surface of a substrate to isolate it from external erosion, preventing damage from scratches, aging, contamination, dust, oil, fingerprints, etc., during production, transportation, or storage. Also known as temporary protective coatings, they provide temporary protection for various substrate surfaces, such as plastics, metals, wood, ceramics, glass, rubber, and pre-coated parts. The protection period typically ranges from a few days to several months, and after protection ends, the coating can be easily peeled off without negatively impacting the substrate surface. Peelable coatings have a wide range of applications. Industrially, they can be used for indoor and outdoor, short-term and long-term protection of both metallic and non-metallic materials. In the civilian sector, they also have broad application prospects, such as protecting cars from color changes, protecting kitchen tiles, providing self-cleaning protection for range hoods, and offering furniture and appliance refinishing services.

[0003] Currently, many well-known foreign paint manufacturers have developed peelable coating materials. Some European and American countries have even widely used these materials in areas such as decking, automobile production, shipbuilding protection, container shipping, and wind turbine blade manufacturing to prevent the effects of dust or welding slag generated during welding and hot working at the joints of components. However, the prices of these peelable coatings from foreign manufacturers are generally higher than the market average and expensive. Currently, many peelable coatings are only suitable for certain substrates and lack peelability for many others, resulting in poor broad applicability and significantly reducing their application range. Furthermore, most peelable coatings require peelable additives to effectively reduce the adhesion between the paint film and the substrate. Common peelable additives include higher fatty acid esters, waxes, surfactants, and silicones. While these additives have some effect, they also have significant side effects, causing various adverse effects on the substrate surface, such as reducing the material's hydrophobicity and weather resistance. Therefore, to address the above technical problems, a new type of peelable coating is necessary. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a method for preparing a superhydrophobic, wear-resistant, water-based peelable coating, addressing the shortcomings of existing technologies. This invention employs a prepolymer dispersion method, firstly using polycarbonate polyol and polyisocyanate as comonomers, and then adding anionic aminoalkyl sulfonate containing hydrophilic groups as a chain extender to prepare a water-based polyurethane dispersion. Adding additives with specific properties and modified fillers, the resulting coating not only has good peelability but also excellent hydrophobicity, excellent wear resistance, and a certain degree of self-cleaning properties.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A method for preparing a superhydrophobic, wear-resistant, water-based peelable coating includes the following steps:

[0007] (1) Preparation of waterborne polyurethane prepolymer;

[0008] (2) Aqueous polyurethane dispersions were prepared using anionic aminoalkyl sulfonates containing hydrophilic groups as chain extenders;

[0009] (3) The above-mentioned waterborne polyurethane dispersion is mixed with modified filler waterborne defoamer, waterborne leveling agent, waterborne wetting agent, hydrophobic agent, waterborne film-forming aid, thickener and deionized water, and pH is adjusted by adding pH adjuster to obtain superhydrophobic surface waterborne peelable coating.

[0010] The modified filler is a polymer-coated SiO2 / carbon nanotube composite filler, and the coating layer consists of an inner layer of polydimethylsiloxane, an outer layer of polycaprolactone, and an outer layer of epoxy resin from the inside out.

[0011] Preferably, the waterborne polyurethane prepolymer is prepared by heating a diol, then removing water by vacuum, cooling, adding diisocyanate, and then heating to react.

[0012] Preferably, the preparation conditions of the waterborne polyurethane prepolymer include at least one of the following:

[0013] The diol is a polycarbonate diol;

[0014] The diisocyanate is isophorone diisocyanate;

[0015] Diols are heated to 100-110°C.

[0016] The vacuum dehydration time is 1-2 hours;

[0017] The temperature for cooling is 45-55℃;

[0018] The heating reaction is carried out at a temperature of 85-95℃ for 1-2 hours.

[0019] Preferably, the preparation process of the waterborne polyurethane dispersion is as follows: anionic aminoalkyl sulfonate containing hydrophilic groups is added to the waterborne polyurethane prepolymer as a chain extender, the reaction continues, the R value is adjusted, and an active diluent is added. When the reaction system reaches the theoretical content of NCO groups in the chemical bond, the temperature is lowered, and a salt-forming agent is added to the reaction system. Deionized water is added under stirring conditions to adjust the solid content, thus obtaining the waterborne polyurethane dispersion.

[0020] Preferably, the preparation of the waterborne polyurethane dispersion includes at least one of the following characteristics:

[0021] The active diluent is N-ethylpyrrolidone;

[0022] The salt-forming agent is triethylamine;

[0023] The continued reaction time is 4-6 hours;

[0024] The solid content of the aqueous polyurethane dispersion is 35-40%.

[0025] Preferably, in the aqueous polyurethane dispersion, the amounts of each component by mass percentage are as follows: 25-35 wt% diol, 8-10 wt% diisocyanate, 1-3 wt% chain extender, 12-15 wt% reactive diluent, 0.5-1.5 wt% salting agent, and 40-50 wt% deionized water.

[0026] Preferably, the method for preparing the modified filler includes the following steps:

[0027] S1: Acidify carbon nanotubes to obtain acidified carbon nanotubes. Add the acidified carbon nanotubes to an aqueous solution of tetraethyl orthosilicate, then add hydrochloric acid solution, stir and mix, add dibutyltin dilaurate and continue stirring, finally add polydimethylsiloxane, mix again, then filter and collect the filtered precipitate.

[0028] S2: Polycaprolactone and epoxy resin are dissolved in ethyl acetate to obtain a suspension. The filtered precipitate is added to the suspension, ultrasonically treated, filtered, and the filtered solid is dried to obtain the modified filler.

[0029] Preferably, in step S1, the acidification treatment conditions include at least one of the following characteristics:

[0030] Acidification treatment uses a nitric acid solution with a concentration of 0.1-0.2 mol / L;

[0031] During acidification treatment, the mass ratio of carbon nanotubes to solution was (0.05-0.1):1000;

[0032] The acidification treatment temperature is 100-110℃, and the treatment time is 30-60 minutes.

[0033] Preferably, the concentration of the tetraethyl orthosilicate aqueous solution is 3-4 mol / L, and the mass ratio of the acidified carbon nanotubes to the tetraethyl orthosilicate aqueous solution is (0.1-0.5):1.

[0034] Preferably, the concentration of the hydrochloric acid solution is 0.1-0.2 mol / L, and the volume ratio of the hydrochloric acid solution to the tetraethyl orthosilicate aqueous solution is (0.05-0.1):1.

[0035] Preferably, the volume ratio of dibutyltin dilaurate to polydimethylsiloxane is 1:(2-4), and the molar ratio of polydimethylsiloxane to tetraethyl orthosilicate is (0.1-0.5):1.

[0036] Preferably, the stirring and mixing temperature is 30°C, the time is 1-2 hours, and the stirring speed is 400-500 rpm; the continued stirring time is 10-20 minutes; and the remixing time is 10-20 minutes.

[0037] Preferably, in S2, the concentrations of polycaprolactone and epoxy resin in the suspension are 0.02-0.03 g / ml and 0.007-0.008 g / ml, respectively; the mass ratio of the filtered precipitate to the suspension is 1:(0.01-0.03).

[0038] Preferably, in S2, the power of the ultrasonic treatment is 400-500W, and the ultrasonic treatment time is 1-2 hours.

[0039] Preferably, the hydrophobic agent is a lotus leaf hydrophobic agent; the water-based defoamer is one or more of water-based polyether siloxane defoamers, water-based mineral oil defoamers, and water-based polymer polyether defoamers; the water-based leveling agent is a water-based polyether siloxane leveling agent; the water-based wetting agent is a water-based acetylsadiol wetting agent; the water-based film-forming aid is one of dipropylene glycol butyl ether and dipropylene glycol phenyl ether; the thickener is a water-based associative polyurethane thickener; and the pH adjuster is dimethylethanolamine.

[0040] Preferably, the amounts of each component in the hydrophobic surface water-based peelable coating, by mass percentage, are as follows: water-based polyurethane dispersion 70-85wt%, modified filler 2-5wt%, deionized water 8-15wt%, water-based defoamer 0.1-0.5wt%, water-based polyether siloxane leveling agent 0.1-0.5wt%, water-based acetylenol wetting agent 0.1-0.5wt%, water-based oxidized polyethylene wax lotus leaf hydrophobic agent 0.5-2wt%, water-based film-forming aid 3-8wt%, water-based associative polyurethane thickener 1-2wt%, and pH adjuster 0.3-0.5wt%.

[0041] Preferably, pigments and fillers are added to the coating to replace part of the waterborne polyurethane dispersion. The mass ratio of pigments and fillers to waterborne polyurethane dispersion is (1-5):5, and the total amount of pigments and fillers and waterborne polyurethane dispersion added is 70-85 wt% of the coating mass. The pigments and fillers include composite high abrasion-resistant texture powder, 1250 mesh silica powder, rutile titanium dioxide, medium pigment carbon black powder, bentonite, and polyamide paste. The mass ratio of composite high abrasion-resistant texture powder, 1250 mesh silica powder, rutile titanium dioxide, medium pigment carbon black powder, bentonite, and polyamide paste is 5-8:10-15:10-12:0.2-0.5:1-2:1-2.

[0042] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0043] This invention provides a superhydrophobic, wear-resistant waterborne peelable coating and its preparation method. The invention employs a prepolymer dispersion method, using polycarbonate polyol and polyisocyanate as comonomers. An anionic aminoalkyl sulfonate chain extender with hydrophilic groups participates in the polycondensation to obtain a polyurethane prepolymer with soft and hard segment blocks. A salt-forming agent is then added for neutralization, and deionized water is added for emulsification and dispersion to obtain a waterborne polyurethane dispersion. The waterborne polyurethane dispersion synthesized using polycarbonate polyol as raw material exhibits high melting point and glass transition temperature, excellent hydrolysis resistance, weather resistance, wear resistance, and biocompatibility. This invention uses a self-made waterborne polyurethane dispersion as the main film-forming material, and then adds modified fillers, deionized water, waterborne defoamers, waterborne leveling agents, waterborne wetting agents, hydrophobic agents, waterborne film-forming aids, and thickeners. The resulting coating can form a continuous, uniform, strong, and transparent protective coating on various substrates and complex-shaped surfaces through spraying, brushing, or rolling. It requires no baking, dries rapidly at room temperature, and releases no harmful gases such as formaldehyde, benzene, or ammonia. After drying and film formation, the coating, due to its good cohesiveness, can be easily peeled off from the device surface in one piece, exhibiting good continuity, non-stickiness, and no damage, penetration, or residue to the substrate. Furthermore, the coating prepared by this invention can serve as a protective layer, effectively isolating it from the intrusion of external media such as air, moisture, salt spray, and microorganisms, and reducing chemical corrosion to achieve an anti-corrosion effect. Moreover, the coating has a certain thickness and elasticity, which can mitigate external impacts and scratches, achieving a protective effect. Furthermore, the coating of this invention contains a certain amount of lotus leaf hydrophobic agent, which can effectively block dust, oil, rust, etc. on the surface of the device and has self-cleaning properties.

[0044] The modified filler of this invention is a polymer-coated SiO2 / carbon nanotube composite filler. First, silica is grown in situ on the surface of acidified carbon nanotubes, improving its dispersibility. Then, a PDMS layer is modified onto the silica surface. Under certain conditions, a polycaprolactone / epoxy resin layer is then modified onto the PDMS layer surface, forming a double hydrophobic protective layer on the silica and carbon nanotube surfaces. PDMS has low surface energy, providing a hydrophobic tail, thus initially improving the hydrophobicity of the nanomaterial surface and effectively preventing the adhesion of dirt and other impurities. Furthermore, polycaprolactone and epoxy resin can enhance self-cleaning properties by altering the surface energy of the materials. Both polycaprolactone and epoxy resin possess good mechanical properties, such as toughness and strength. When combined with silica and dispersed in a polyurethane matrix, they can increase the internal strength of the composite material and improve its resistance to external wear. Silica itself is also a hard material; its presence acts as a physical barrier, reducing direct contact and stress on the matrix material, thereby improving wear resistance. Furthermore, PDMS has good elasticity, which can absorb and disperse scratching force, reducing direct damage to the polyurethane matrix. Meanwhile, the toughness of polycaprolactone and epoxy resin also helps the material resist cracking or breakage when subjected to scratches. In summary, the addition of modified fillers improves the material's wear resistance, self-cleaning properties, and hydrophobicity to a certain extent. Detailed Implementation

[0045] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0046] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0047] To address the problems identified in the background art, this invention provides a method for preparing a superhydrophobic, wear-resistant, water-based peelable coating. This invention employs a prepolymer dispersion method, using polycarbonate polyol and polyisocyanate as comonomers, and employing anionic chain extenders containing hydrophilic groups (aminoalkyl sulfonate) to participate in polycondensation, resulting in a water-based polyurethane dispersion with high melting point and glass transition temperature, excellent hydrolysis resistance, weather resistance, wear resistance, and biocompatibility. Furthermore, this invention adds a certain amount of functional additives and polycaprolactone / epoxy resin / PDMS-modified silica / carbon nanotubes as modified fillers to the water-based polyurethane dispersion. The resulting coating not only exhibits good dispersibility but also requires no baking, dries rapidly at room temperature, and releases no harmful gases such as formaldehyde, benzene, or ammonia. The coating has good peelability, does not stick when peeled off, and does not damage, penetrate, or leave residue on the substrate. It can isolate the intrusion of external media such as air, water vapor, salt spray, and microorganisms, and reduce chemical corrosion, thus having a good anti-corrosion effect. In addition, the coating has a certain thickness and elasticity, which can alleviate external impacts and man-made scratches, achieving a protective effect, and also has a certain self-cleaning property.

[0048] A method for preparing a superhydrophobic, wear-resistant, water-based peelable coating includes the following steps:

[0049] (1) Preparation of waterborne polyurethane prepolymer;

[0050] (2) Aqueous polyurethane dispersions were prepared using anionic aminoalkyl sulfonates containing hydrophilic groups as chain extenders;

[0051] (3) The above-mentioned waterborne polyurethane dispersion is mixed with modified filler waterborne defoamer, waterborne leveling agent, waterborne wetting agent, hydrophobic agent, waterborne film-forming aid, thickener and deionized water, and pH is adjusted by adding pH adjuster to obtain superhydrophobic surface waterborne peelable coating.

[0052] The modified filler is a polymer-coated SiO2 / carbon nanotube composite filler, and the coating layer consists of an inner layer of polydimethylsiloxane, an outer layer of polycaprolactone, and an outer layer of epoxy resin from the inside out.

[0053] In some embodiments, the waterborne polyurethane prepolymer is prepared by heating a diol, then removing water by vacuuming, cooling, adding diisocyanate, and then heating to react.

[0054] In some embodiments, the preparation conditions of the waterborne polyurethane prepolymer include at least one of the following:

[0055] The diol is a polycarbonate diol;

[0056] The diisocyanate is isophorone diisocyanate;

[0057] Diols are heated to 100-110°C.

[0058] The vacuum dehydration time is 1-2 hours;

[0059] The temperature for cooling is 45-55℃;

[0060] The heating reaction is carried out at a temperature of 85-95℃ for 1-2 hours.

[0061] In the preparation of waterborne polyurethane prepolymers, the choice of diol and diisocyanate has a certain impact on the performance of the prepolymer. The type of diol affects the molecular weight and flexibility of the prepolymer, which in turn affects the hardness and abrasion resistance of the final polyurethane. The choice of diisocyanate affects the crosslinking structure and chemical temperature resistance of the polyurethane. This invention uses polycarbonate diol and isophorone diisocyanate as polymerizing monomers. The polycarbonate diol is dehydrated under certain conditions to improve the water resistance of the polyurethane. Furthermore, this invention improves the water resistance, weather resistance, and abrasion resistance of the final waterborne polyurethane dispersion by controlling the crosslinking temperature and crosslinking time.

[0062] In some embodiments, the preparation process of the waterborne polyurethane dispersion is as follows: anionic aminoalkyl sulfonate containing hydrophilic groups is added to the waterborne polyurethane prepolymer as a chain extender, the reaction continues, the R value is adjusted, and an active diluent is added. When the reaction system reaches the theoretical content of NCO groups in the chemical bond, the temperature is lowered, and a salt-forming agent is added to the reaction system. Deionized water is added under stirring conditions to adjust the solid content, thus obtaining the waterborne polyurethane dispersion.

[0063] In some embodiments, the preparation of the aqueous polyurethane dispersion includes at least one of the following characteristics:

[0064] The active diluent is N-ethylpyrrolidone;

[0065] The salt-forming agent is triethylamine;

[0066] The continued reaction time is 4-6 hours;

[0067] The solid content of the aqueous polyurethane dispersion is 35-40%.

[0068] This invention uses polycarbonate diol as the diol, which has a regular structure and produces only CO2 upon hydrolysis, unlike other polyester polyols which produce carboxylic acids upon hydrolysis, accumulating in the polymer and accelerating hydrolysis. Furthermore, it exhibits excellent water resistance, chemical solvent resistance, resistance to damp heat aging, oil resistance, abrasion resistance, weather resistance, biostability, and compatibility. This invention uses isophorone diisocyanate (IPDI) as a raw material, which does not contain benzene rings, fundamentally enhancing the yellowing resistance of waterborne polyurethane and improving its light stability, weather resistance, and mechanical properties. This invention uses N-ethylpyrrolidone (NEP) as a reactive diluent, which is highly polar and miscible with water and common organic solvents in any proportion. This invention uses anionic aminoalkyl sulfonate containing hydrophilic groups as a chain extender. It contains two amino groups (primary amine + secondary amine), which can be introduced into the polyurethane backbone as an excellent hydrophilic monomer to enhance the hydrophilicity of the system, thereby achieving a self-emulsification effect. This allows the polyurethane particles to achieve a perfect phase transition in water, resulting in a relatively small emulsion particle size.

[0069] In some embodiments, the amounts of each component in the aqueous polyurethane dispersion, by mass percentage, are as follows: 25-35 wt% diol, 8-10 wt% diisocyanate, 1-3 wt% chain extender, 12-15 wt% reactive diluent, 0.5-1.5 wt% salting agent, and 40-50 wt% deionized water.

[0070] In the preparation of waterborne polyurethane dispersions, diols, as the main hydroxyl compounds, react with diisocyanates to form polyurethane segments. Too little diol leads to incomplete polymer segments, while too much may increase viscosity or affect dispersion performance. Diisocyanates, acting as the hard segments of polyurethane, react with diols to form polyurethane segments, affecting the product's hardness, abrasion resistance, and mechanical properties. Too little diol leads to decreased physical properties, while too much may affect dispersion performance and the coating's weather resistance. Chain extenders control the molecular weight of polyurethane, affecting its viscosity and mechanical properties. Too little chain extender results in insufficient polymer molecular weight, while too much may increase dispersion viscosity or affect dispersion performance. Reactive diluents adjust the viscosity and flowability of the dispersion to ensure suitable application performance. Too little diluent leads to excessively high dispersion concentration, which may affect the drying performance and water resistance of the coating film. Salt-forming agents adjust the pH of the dispersion, affecting dispersion performance and stability. Too little salt-forming agent leads to unstable dispersion, while too much may affect its solubility and processing performance. Deionized water is used as both a solvent and a dispersion medium to ensure uniform dispersion and stability of all components. Insufficient dosage will result in inadequate dispersion concentration, while excessive dosage may affect the solids content and performance stability of the coating. This invention optimizes the dosage of each component to obtain a high-performance waterborne polyurethane dispersion, thereby improving the performance of coatings using waterborne polyurethane dispersions as the main film-forming substance.

[0071] In some embodiments, the method for preparing the modified filler includes the following steps:

[0072] S1: Acidify carbon nanotubes to obtain acidified carbon nanotubes. Add the acidified carbon nanotubes to an aqueous solution of tetraethyl orthosilicate, then add hydrochloric acid solution, stir and mix, add dibutyltin dilaurate and continue stirring, finally add polydimethylsiloxane, mix again, then filter and collect the filtered precipitate.

[0073] S2: Polycaprolactone and epoxy resin are dissolved in ethyl acetate to obtain a suspension. The filtered precipitate is added to the suspension, ultrasonically treated, filtered, and the filtered solid is dried to obtain the modified filler.

[0074] In some embodiments, the acidification treatment conditions in step S1 include at least one of the following characteristics:

[0075] Acidification treatment uses a nitric acid solution with a concentration of 0.1-0.2 mol / L;

[0076] During acidification treatment, the mass ratio of carbon nanotubes to solution was (0.05-0.1):1000;

[0077] The acidification treatment temperature is 100-110℃, and the treatment time is 30-60 minutes.

[0078] In some embodiments, the concentration of the tetraethyl orthosilicate aqueous solution is 3-4 mol / L, and the mass ratio of the acidified carbon nanotubes to the tetraethyl orthosilicate aqueous solution is (0.1-0.5):1.

[0079] In some embodiments, the concentration of the hydrochloric acid solution is 0.1-0.2 mol / L, and the volume ratio of the hydrochloric acid solution to the tetraethyl orthosilicate aqueous solution is (0.05-0.1):1.

[0080] In some embodiments, the volume ratio of dibutyltin dilaurate to polydimethylsiloxane is 1:(2-4), and the molar ratio of polydimethylsiloxane to tetraethyl orthosilicate is (0.1-0.5):1.

[0081] In some embodiments, the stirring and mixing temperature is 30°C, the time is 1-2 hours, and the stirring speed is 400-500 rpm; the continued stirring time is 10-20 minutes; and the remixing time is 10-20 minutes.

[0082] In step S1, this invention first optimizes the acidification treatment conditions to improve the surface activity of carbon nanotubes without damaging their structure, thus facilitating silica deposition. Furthermore, this invention optimizes the conditions for preparing silica through hydrolysis, resulting in a well-dispersed silica / carbon nanotube material. Finally, a layer of PDMS is added to its surface to improve the material's hydrophobicity and wear resistance. During modification, excessive or insufficient PDMS addition not only increases costs but also leads to insufficient reaction between some PDMS and silica, resulting in weak bonding between the PDMS layer and silica, making it prone to peeling and reducing the material's adhesion and durability. Insufficient PDMS addition fails to form a sufficient PDMS coating layer, resulting in incomplete coating of the silica surface and affecting the material's hydrophobic and protective properties. Therefore, the amount of PDMS used needs to be carefully controlled.

[0083] In some embodiments, in S2, the concentrations of polycaprolactone and epoxy resin in the suspension are 0.02-0.03 g / ml and 0.007-0.008 g / ml, respectively; the mass ratio of the filtered precipitate to the suspension is 1:(0.01-0.03).

[0084] In some embodiments, in S2, the power of the ultrasonic treatment is 400-500W, and the duration of the ultrasonic treatment is 1-2 hours.

[0085] In some embodiments, the hydrophobic agent is a lotus leaf hydrophobic agent; the water-based defoamer is one or more of water-based polyether siloxane defoamers, water-based mineral oil defoamers, and water-based polymer polyether defoamers; the water-based leveling agent is a water-based polyether siloxane leveling agent; the water-based wetting agent is a water-based acetylsadiol wetting agent; the water-based film-forming aid is one of dipropylene glycol butyl ether and dipropylene glycol phenyl ether; the thickener is a water-based associative polyurethane thickener; and the pH adjuster is dimethylethanolamine.

[0086] To improve the hydrophobicity of the material and its compatibility with the coating matrix, this invention also modifies the PDMS layer with a polycaprolactone / epoxy resin layer. During modification, excessive addition of polycaprolactone / epoxy resin can actually reduce the hydrophobicity and wear resistance of the material surface. This is mainly due to the unevenness of the polycaprolactone / epoxy resin layer on the material surface. Insufficient addition of polycaprolactone and epoxy resin will lead to inadequate coating, thereby affecting the wear resistance and hydrophobicity of the coating.

[0087] In some embodiments, the amounts of each component in the superhydrophobic waterborne peelable coating, by mass percentage, are as follows: waterborne polyurethane dispersion 70-85 wt%, modified filler 2-5 wt%, deionized water 8-15 wt%, waterborne defoamer 0.1-0.5 wt%, waterborne polyether siloxane leveling agent 0.1-0.5 wt%, waterborne acetylenol wetting agent 0.1-0.5 wt%, waterborne oxidized polyethylene wax lotus leaf hydrophobic agent 0.5-2 wt%, waterborne film-forming aid 3-8 wt%, waterborne associative polyurethane thickener 1-2 wt%, and pH adjuster 0.3-0.5 wt%.

[0088] In some embodiments, pigments and fillers are added to the coating to replace part of the waterborne polyurethane dispersion. The mass ratio of pigments and fillers to waterborne polyurethane dispersion is (1-5):5, and the total amount of pigments and fillers and waterborne polyurethane dispersion added is 70-85 wt% of the coating mass. The pigments and fillers include composite high abrasion-resistant texture powder, 1250 mesh silica powder, rutile titanium dioxide, medium pigment carbon black powder, bentonite, and polyamide paste. The mass ratio of composite high abrasion-resistant texture powder, 1250 mesh silica powder, rutile titanium dioxide, medium pigment carbon black powder, bentonite, and polyamide paste is 5-8:10-15:10-12:0.2-0.5:1-2:1-2.

[0089] This invention incorporates a certain amount of lotus leaf hydrophobic agent into an aqueous polyurethane dispersion to improve the material's hydrophobic properties. This agent possesses strong lotus leaf hydrophobic characteristics and scratch resistance. Adding it to water-based coatings imparts water and stain resistance, self-cleaning, and maintenance properties to the paint film, enhancing its anti-fouling and anti-sticking capabilities and protecting the cleanliness of the coating surface. Dimethylethanolamine is added as a pH adjuster, exhibiting a lower odor compared to other amine neutralizing agents. The addition of an aqueous acetylenic diol wetting agent effectively reduces the dynamic surface tension of the system while providing excellent substrate wetting ability. This invention also incorporates appropriate amounts of modified fillers for further modification, improving the coating's hydrophobicity while also enhancing its abrasion resistance, corrosion resistance, and self-cleaning properties.

[0090] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0091] In the following examples and comparative examples, the sources or performance parameters of each raw material are as follows:

[0092] Polycarbonate diol: Covestro Desmophen-C1200; Isophorone diisocyanate: Wanhua WANNATE® IPDI; Waterborne defoamer: BYK Additive BYK-024; Waterborne polyether siloxane leveling agent: BYK Additive BYK-333; Lotus leaf hydrophobic agent: Waterborne lotus leaf hydrophobic agent XH-5012, Dongguan Xuyihua Chemical Co., Ltd.; Waterborne film-forming aid: Dipropylene glycol butyl ether; Waterborne associative polyurethane thickener: Hemings-299-Waterborne polyurethane associative thickener; Anionic aminoalkyl sulfonate chain extender with hydrophilic groups: Xingusheng hydrophilic chain extender aminosulfonate AAS-Na, Guangzhou Xingusheng Chemical Technology Co., Ltd.; Carbon nanotubes: Avoidance carbon nanotubes purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., with a diameter of 5-15 nm, an inner diameter of 2-5 nm, purity >95%, and a length of 0.5-2 nm. μm, specific surface area: >200 m² 2 / g, tap density: 0.27 g / cm³ 3 True density: ~2.1 g / cm3, electrical conductivity: >100s / cm; Composite high abrasion resistant sand texture powder: Twax-4000, Nanjing Tianshi New Material Technology Co., Ltd.; Bentonite: Hemings LT-Bentonite; Polyamide paste: Disparon-AQ-630; Polydimethylsiloxane: PMX-10, Shanghai Hongzhuang Chemical Technology Co., Ltd.; Polycaprolactone: weight average molecular weight of 30,000.

[0093] Example 1

[0094] I. Preparation of modified fillers:

[0095] Carbon nanotubes and a 0.15 mol / L nitric acid solution were mixed at a mass ratio of 0.05:1000 and impregnated at 100°C for 30 min in the dark. After treatment, the solid was dried to obtain acidified carbon nanotubes. 0.2 g of acidified carbon nanotubes were added to 1 g of a 3.5 mol / L tetraethyl orthosilicate aqueous solution, followed by a 0.15 mol / L hydrochloric acid solution (volume ratio of hydrochloric acid solution to tetraethyl orthosilicate aqueous solution was 0.1:1). The mixture was stirred at 30°C and 450 rpm for 1 h, and then dibutyltin dilaurate was added. (The volume ratio of dibutyltin dilaurate to polydimethylsiloxane is 1:3), continue stirring for 10 min, finally add polydimethylsiloxane (the molar ratio of polydimethylsiloxane to tetraethyl orthosilicate is 0.3:1), mix for another 10 min, then filter and collect the precipitate; dissolve 1 g of polycaprolactone and 0.35 g of epoxy resin in 50 ml of ethyl acetate to obtain a suspension, add the above precipitate to the suspension (the mass ratio of precipitate to suspension is 1:0.01), sonicate at 500 W for 1 h, then filter, dry the filtered solid to obtain the modified filler;

[0096] II. Preparation of waterborne polyurethane prepolymer:

[0097] In a double-jacketed reactor equipped with a mechanical stirrer, add 25g of polycarbonate diol, heat to 100℃, stir evenly, then vacuum dehydrate for 2 hours, cool to 45-55℃, slowly add 8g of IPDI, and after the IPDI is completely added, raise the system temperature to 90℃, keep warm and stir for 2 hours to obtain water-based polyurethane prepolymer.

[0098] III. Preparation of waterborne polyurethane dispersions:

[0099] 1g of anionic aminoalkyl sulfonate chain extender containing hydrophilic groups was slowly added to the above-mentioned waterborne polyurethane prepolymer. The reaction was continued at 90℃ for 5h. The R value was adjusted, and 12g of N-ethylpyrrolidone was added to dilute the viscosity of the reaction system. The theoretical content of NCO chemical bonds in the reaction system was determined by di-n-butylamine titration. The temperature was lowered, and triethylamine was added to adjust the pH of the reaction system to 7. Deionized water was added to the reaction system under high-speed stirring to emulsify it. Finally, a waterborne polyurethane dispersion with a solid content of 38% was obtained.

[0100] IV. Preparation of superhydrophobic, abrasion-resistant water-based peelable varnish coatings:

[0101] Fix the stirring rod of the high-speed disperser in the center of the dispersion container. Slowly add 15g of deionized water, 70g of waterborne polyurethane dispersion, 2g of modified filler, 0.3g of waterborne defoamer, 0.3g of waterborne polyether siloxane leveling agent, 0.4g of waterborne acetylenol wetting agent, 2g of lotus leaf hydrophobic agent, and 8g of waterborne film-forming aid at a stirring speed of 500 rpm. Then increase the stirring speed to 1000 rpm and disperse at high speed for 15 minutes. Add 1.5g of waterborne associative polyurethane thickener and 0.5g of dimethyl ethanolamine dropwise. Increase the stirring speed to 1200 rpm and continue dispersing for 30 minutes to obtain a superhydrophobic, wear-resistant waterborne peelable varnish coating.

[0102] Example 2

[0103] I. Preparation of modified fillers:

[0104] Carbon nanotubes and a 0.2 mol / L nitric acid solution were mixed at a mass ratio of 0.07:1000 and impregnated at 100°C for 30 min in the dark. After treatment, the solid was dried to obtain acidified carbon nanotubes. 0.23 g of acidified carbon nanotubes were added to 1 g of a 3.5 mol / L tetraethyl orthosilicate aqueous solution, followed by the addition of a 0.1 mol / L hydrochloric acid solution (volume ratio of hydrochloric acid solution to tetraethyl orthosilicate aqueous solution was 0.1:1). The mixture was stirred at 30°C and 450 rpm for 1 h, and then dibutyltin dilaurate was added. The volume ratio of dibutyltin dilaurate to polydimethylsiloxane was 1:3. Stirring was continued for 10 minutes. Finally, polydimethylsiloxane (molar ratio of polydimethylsiloxane to tetraethyl orthosilicate was 0.4:1) was added, and the mixture was stirred for another 10 minutes. The mixture was then filtered, and the precipitate was collected. 1.2 g of polycaprolactone and 0.35 g of epoxy resin were dissolved in 50 ml of ethyl acetate to obtain a suspension. The filtered precipitate was added to the suspension (mass ratio of precipitate to suspension was 1:0.02). The mixture was ultrasonically treated at 500 W for 1 hour, then filtered. The filtered solid was dried to obtain the modified filler.

[0105] II. Preparation of waterborne polyurethane prepolymer:

[0106] In a double-jacketed reactor equipped with a mechanical stirrer, 30g of polycarbonate diol was added, heated to 100℃, stirred evenly, then vacuumed to remove water for 2 hours, cooled to 50℃, and 9wt% IPDI was slowly added. After the IPDI was completely added, the system temperature was raised to 90℃, and the reaction was carried out with stirring for 2 hours to obtain waterborne polyurethane prepolymer.

[0107] III. Preparation of waterborne polyurethane dispersions:

[0108] 3g of anionic aminoalkyl sulfonate chain extender containing hydrophilic groups was slowly added to the above-mentioned waterborne polyurethane prepolymer. The reaction was continued at 90℃ for 5h. The R value was adjusted, and 14gwt%N-ethylpyrrolidone was added to dilute the viscosity of the reaction system. The theoretical content of NCO chemical bonds in the reaction system was determined by di-n-butylamine titration. The temperature was lowered, and triethylamine was added to adjust the pH of the reaction system to 7. Deionized water was added to the reaction system under high-speed stirring to emulsify it. Finally, a waterborne polyurethane dispersion with a solid content of 40g was obtained.

[0109] IV. Preparation of superhydrophobic, abrasion-resistant water-based peelable varnish coatings:

[0110] Fix the stirring rod of the high-speed disperser in the center of the dispersion container. Slowly add 10g of deionized water, 75g of waterborne polyurethane dispersion, 3g of modified filler, 0.5g of waterborne defoamer, 0.5g of waterborne polyether siloxane leveling agent, 0.5g of waterborne acetylenol wetting agent, 1g of lotus leaf hydrophobic agent, and 7g of waterborne film-forming aid at a stirring speed of 500 rpm. Then increase the stirring speed to 1000 rpm and disperse at high speed for 15 minutes. Add 2g of waterborne associative polyurethane thickener and 0.5g of dimethyl ethanolamine dropwise. Increase the stirring speed to 1200 rpm and continue dispersing for 30 minutes to obtain a superhydrophobic, wear-resistant waterborne peelable varnish coating.

[0111] Example 3

[0112] I. Preparation of modified fillers:

[0113] Carbon nanotubes and a 0.2 mol / L nitric acid solution were mixed at a mass ratio of 0.1:1000 and impregnated at 100°C for 30 min in the dark. After treatment, the solid was dried to obtain acidified carbon nanotubes. 0.3 g of acidified carbon nanotubes were added to 1 g of a 3.5 mol / L tetraethyl orthosilicate aqueous solution, followed by the addition of a 0.1 mol / L hydrochloric acid solution (volume ratio of hydrochloric acid solution to tetraethyl orthosilicate aqueous solution was 0.06:1). The mixture was stirred at 30°C and 450 rpm for 1 h. Dibutyltin dilaurate (dibutyltin dilaurate) was then added. The volume ratio of dibutyltin cinnamate to polydimethylsiloxane is 1:2. Stirring is continued for 10 minutes, and finally polydimethylsiloxane (the molar ratio of polydimethylsiloxane to tetraethyl orthosilicate is 0.3:1) is added. The mixture is then stirred for another 10 minutes, filtered, and the precipitate is collected. S2: 1.5 g of polycaprolactone and 0.35 g of epoxy resin are dissolved in 50 ml of ethyl acetate to obtain a suspension. The filtered precipitate is added to the suspension (the mass ratio of the precipitate to the suspension is 1:0.03). The mixture is ultrasonically treated at 400 W for 2 hours, then filtered. The filtered solid is dried to obtain the modified filler.

[0114] II. Preparation of waterborne polyurethane prepolymer:

[0115] In a double-jacketed reactor equipped with a mechanical stirrer, 30g of polycarbonate diol was added, heated to 100°C, stirred evenly, then vacuumed to remove water for 2 hours, cooled to 40°C, and 10g of IPDI was slowly added. After the IPDI was completely added, the system temperature was raised to 90°C, and the reaction was carried out with stirring for 2 hours to obtain waterborne polyurethane prepolymer.

[0116] III. Preparation of waterborne polyurethane dispersions:

[0117] 2g of anionic aminoalkyl sulfonate chain extender containing hydrophilic groups was slowly added to the above-mentioned waterborne polyurethane prepolymer. The reaction was continued at 90℃ for 5h. The R value was adjusted, and 15g of N-ethylpyrrolidone was added to dilute the viscosity of the reaction system. The theoretical content of NCO chemical bonds in the reaction system was determined by di-n-butylamine titration. The temperature was lowered, and triethylamine was added to adjust the pH of the reaction system to 7. Deionized water was added to the reaction system under high-speed stirring to emulsify it. Finally, a waterborne polyurethane dispersion with a solid content of 40% was obtained.

[0118] IV. Preparation of superhydrophobic, abrasion-resistant water-based peelable varnish coatings:

[0119] Fix the stirring rod of the high-speed disperser in the center of the dispersion container. Slowly add 13.5g of deionized water, 70g of waterborne polyurethane dispersion, 5g of modified filler, 0.5g of waterborne defoamer, 0.5g of waterborne polyether siloxane leveling agent, 0.5g of waterborne acetylenol wetting agent, 2g of lotus leaf hydrophobic agent, and 6g of waterborne film-forming aid at a stirring speed of 500 rpm. Then increase the stirring speed to 1000 rpm and disperse at high speed for 15 minutes. Add 1.5g of waterborne associative polyurethane thickener and 0.5g of dimethyl ethanolamine dropwise. Increase the stirring speed to 1200 rpm and continue dispersing for 30 minutes to obtain a superhydrophobic, wear-resistant waterborne peelable varnish coating.

[0120] Example 4

[0121] I. Preparation of modified fillers:

[0122] Carbon nanotubes and a 0.1 mol / L nitric acid solution were mixed at a mass ratio of 0.1:1000 and impregnated at 100°C for 30 min in the dark. After treatment, the solid was dried to obtain acidified carbon nanotubes. 0.4 g of acidified carbon nanotubes were added to 1 g of a 3.5 mol / L tetraethyl orthosilicate aqueous solution, followed by the addition of a 0.15 mol / L hydrochloric acid solution (volume ratio of hydrochloric acid solution to tetraethyl orthosilicate aqueous solution was 0.08:1). The mixture was stirred at 30°C and 450 rpm for 1 h. Dibutyltin dilaurate (dibutyltin dilaurate) was then added. The volume ratio of dibutyltin laurate to polydimethylsiloxane is 1:3. Stir for 10 minutes, then add polydimethylsiloxane (molar ratio of polydimethylsiloxane to tetraethyl orthosilicate is 0.3:1), mix for another 10 minutes, filter, and collect the precipitate. S2: Dissolve 1.5g polycaprolactone and 0.35g epoxy resin in 50ml ethyl acetate to obtain a suspension. Add the above precipitate to the suspension (mass ratio of precipitate to suspension is 1:0.025), sonicate at 500W for 1 hour, filter, and dry the filtered solid to obtain the modified filler.

[0123] II. Preparation of waterborne polyurethane prepolymer:

[0124] In a double-jacketed reactor equipped with a mechanical stirrer, add 30g of polycarbonate diol, heat to 100℃, stir evenly, then vacuum dehydrate for 2 hours, cool to 50℃, slowly add 10g of IPDI, and after the IPDI is completely added, raise the system temperature to 90℃, keep warm and stir for 2 hours to obtain waterborne polyurethane prepolymer.

[0125] III. Preparation of waterborne polyurethane dispersions:

[0126] 3g of anionic aminoalkyl sulfonate chain extender containing hydrophilic groups was slowly added to the above-mentioned waterborne polyurethane prepolymer. The reaction was continued at 90℃ for 5h. The R value was adjusted, and 15g of N-ethylpyrrolidone was added to dilute the viscosity of the reaction system. The theoretical content of NCO chemical bonds in the reaction system was determined by di-n-butylamine titration. The temperature was lowered, and triethylamine was added to adjust the pH of the reaction system to 7. Deionized water was added to the reaction system under high-speed stirring to emulsify it. Finally, a waterborne polyurethane dispersion with a solid content of 40g was obtained.

[0127] IV. Preparation of superhydrophobic, abrasion-resistant water-based peelable varnish coatings:

[0128] Fix the stirring rod of the high-speed disperser in the center of the dispersion container. Slowly add 10g of deionized water, 72.9g of waterborne polyurethane dispersion, 4.5g of modified filler, 0.4g of waterborne defoamer, 0.4g of waterborne polyether siloxane leveling agent, 0.4g of waterborne acetylenol wetting agent, 2g of lotus leaf hydrophobic agent, and 7g of waterborne film-forming aid at a stirring speed of 500 rpm. Then increase the stirring speed to 1000 rpm and disperse at high speed for 15 minutes. Add 2g of waterborne associative polyurethane thickener and 0.4g of dimethyl ethanolamine dropwise. Increase the stirring speed to 1200 rpm and continue dispersing for 30 minutes to obtain a superhydrophobic, wear-resistant waterborne peelable varnish coating.

[0129] Example 5

[0130] I. Preparation of modified fillers:

[0131] Carbon nanotubes and a 0.1 mol / L nitric acid solution were mixed at a mass ratio of 0.1:1000 and impregnated at 100°C for 30 min in the dark. After treatment, the solid was dried to obtain acidified carbon nanotubes. 0.4 g of acidified carbon nanotubes were added to 1 g of a 3.5 mol / L tetraethyl orthosilicate aqueous solution, followed by the addition of a 0.15 mol / L hydrochloric acid solution (volume ratio of hydrochloric acid solution to tetraethyl orthosilicate aqueous solution was 0.08:1). The mixture was stirred at 30°C and 450 rpm for 1 h. Dibutyltin dilaurate (dibutyltin dilaurate) was then added. The volume ratio of dibutyltin laurate to polydimethylsiloxane is 1:3. Stir for 10 minutes, then add polydimethylsiloxane (molar ratio of polydimethylsiloxane to tetraethyl orthosilicate is 0.3:1), mix for another 10 minutes, filter, and collect the precipitate. S2: Dissolve 1.5g polycaprolactone and 0.35g epoxy resin in 50ml ethyl acetate to obtain a suspension. Add the above precipitate to the suspension (mass ratio of precipitate to suspension is 1:0.025), sonicate at 500W for 1 hour, filter, and dry the filtered solid to obtain the modified filler.

[0132] II. Preparation of waterborne polyurethane prepolymer:

[0133] In a double-jacketed reactor equipped with a mechanical stirrer, add 30g of polycarbonate diol, heat to 100℃, stir evenly, then vacuum dehydrate for 2 hours, cool to 50℃, slowly add 10g of IPDI, and after the IPDI is completely added, raise the system temperature to 90℃, keep warm and stir for 2 hours to obtain waterborne polyurethane prepolymer.

[0134] III. Preparation of waterborne polyurethane dispersions:

[0135] 3g of anionic aminoalkyl sulfonate chain extender containing hydrophilic groups was slowly added to the above-mentioned waterborne polyurethane prepolymer. The reaction was continued at 90℃ for 5h. The R value was adjusted, and 15g of N-ethylpyrrolidone was added to dilute the viscosity of the reaction system. The theoretical content of NCO chemical bonds in the reaction system was determined by di-n-butylamine titration. The temperature was lowered, and triethylamine was added to adjust the pH of the reaction system to 7. Deionized water was added to the reaction system under high-speed stirring to emulsify it. Finally, a waterborne polyurethane dispersion with a solid content of 40g was obtained.

[0136] IV. Preparation of Pigment Paste:

[0137] Add 10g of deionized water to a mixing container. Fix the stirring rod of a high-speed disperser in the center of the container. Slowly add 0.4g of water-based defoamer and 0.4g of water-based acetylenol wetting agent at a stirring speed of 500 rpm. Increase the stirring speed to 1000 rpm and disperse at high speed for 5 minutes. Reduce the stirring speed of the disperser to 500 rpm and add 3.6g of composite high wear-resistant sand texture powder, 4.5g of 1250 mesh silica powder, 4.5g of rutile titanium dioxide, 0.09g of medium pigment carbon black powder, 0.45g of bentonite, and 0.45g of polyamide paste. Increase the stirring speed to 1500 rpm and disperse for 30 minutes. Then, grind the mixture in a sand mill until the fineness is ≤15μm. The result is a qualified water-based resin-free ice-gray paste.

[0138] V. Preparation of superhydrophobic, wear-resistant, water-based peelable ice-gray surface coating:

[0139] Add the above-mentioned color paste to the mixing tank, and then add 59.31g of the above-prepared waterborne polyurethane dispersion, 4.5g of modified filler, 0.4g of dimethylethanolamine, 0.4g of waterborne polyether siloxane leveling agent, 2g of lotus leaf hydrophobic agent, and 7g of waterborne film-forming aid to the mixing tank at 500 rpm. Increase the stirring speed to 1000 rpm and disperse at high speed for 15 minutes. Add 2g of waterborne associative polyurethane thickener, increase the stirring speed to 1200 rpm and continue dispersing for 30 minutes to obtain a superhydrophobic, wear-resistant waterborne peelable ice-gray surface coating.

[0140] Comparative Example 1

[0141] Compared with Example 1, the difference is that no modified filler was added in this comparative example, and the other conditions are the same as in Example 1.

[0142] Comparative Example 2

[0143] Compared with Example 1, the difference is that no acidified carbon nanotubes were added when preparing the modified filler in this comparative example, and the other conditions were the same as in Example 1.

[0144] Comparative Example 3

[0145] Compared with Example 1, the difference is that in this comparative example, the PDMS layer and polycaprolactone / epoxy resin layer are not modified when preparing the modified filler, and other conditions are the same as in Example 1.

[0146] Comparative Example 4

[0147] Compared with Example 1, the difference is that in this comparative example, only the PDMS layer was modified and the polycaprolactone / epoxy resin layer was not modified when preparing the modified filler, and other conditions were the same as in Example 1.

[0148] Comparative Example 5

[0149] Compared with Example 1, the difference is that in this comparative example, only the polycaprolactone / epoxy resin layer was modified during the preparation of the modified filler, and the PDMS layer was not modified. Other conditions were the same as in Example 1.

[0150] The coatings obtained in the above embodiments and comparative examples were subjected to performance tests. The test methods and results are as follows:

[0151] The sample substrate used in the experiment was a 150mm×70mm×2mm tinplate. Before the experiment, the substrate needed surface treatment: first, the tinplate was sanded horizontally and vertically with sandpaper of appropriate coarseness; then, the sanded surface was wiped with xylene; finally, it was wiped clean with anhydrous ethanol and placed in a vacuum drying oven for later use. Before spraying, the air output of the spray gun was adjusted, the tinplate was placed in a fume hood, the fan and water curtain were turned on, and the distance between the spray gun and the tinplate was kept appropriate. Then, the coating was sprayed onto the sample substrate in an "S" shaped motion. The number of sprays for each sample was the same to ensure a consistent coating thickness, controlling the film thickness to 30μm. After spraying, the samples were allowed to dry on the surface and then placed in a ventilated area to dry for later use.

[0152] Water contact angle: Tested according to the method of national standard GB / T 23744-2009.

[0153] Peelability test: In northern China, samples were placed in an open-air environment for 6 months between December and May of the following year. After that, the samples were torn by hand to check whether the film layer could be completely removed.

[0154] Wear resistance: GB / T1768, test conditions are 60r / min, load 1000g, CS-10 grinding wheel.

[0155] Tensile strength: Tensile tests were conducted on a material testing machine using a 100N force sensor (Instron 5567A, USA). A constant strain rate of 50 mm / min was used. To ensure data accuracy, each sample was tested at least three times.

[0156] The test results are shown in Table 1.

[0157] Table 1

[0158]

[0159] As can be seen from the data in Table 1 above, compared with the comparative example, the present invention adds an appropriate amount of filler to the coating and performs certain treatments on the filler. The resulting coating not only has good hydrophobicity, but also excellent wear resistance, good mechanical properties, and good peelability.

[0160] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A method for preparing a superhydrophobic, wear-resistant, water-based peelable coating, characterized in that, Includes the following steps: (1) The diol is heated, then the water is removed by vacuuming, then the temperature is lowered, diisocyanate is added, and the temperature is raised to react, thus obtaining the waterborne polyurethane prepolymer. (2) Aqueous polyurethane dispersions were prepared using anionic aminoalkyl sulfonates containing hydrophilic groups as chain extenders; (3) The above-mentioned waterborne polyurethane dispersion is mixed with modified filler, waterborne defoamer, waterborne leveling agent, waterborne wetting agent, hydrophobic agent, waterborne film-forming aid, thickener and deionized water, and pH is adjusted by adding pH adjuster to obtain superhydrophobic surface waterborne peelable coating. The modified filler is a polymer-coated SiO2 / carbon nanotube composite filler, with the coating layer consisting of an inner layer of polydimethylsiloxane, an outer layer of polycaprolactone, and an outer layer of epoxy resin from the inside out. In the waterborne polyurethane dispersion, the amounts of each component, by mass percentage, are as follows: diol 25-35 wt%, diisocyanate 8-10 wt%, chain extender 1-3 wt%, reactive diluent 12-15 wt%, salt-forming agent 0.5-1.5 wt%, and deionized water 40-50 wt%. The amounts of each component in the hydrophobic waterborne peelable coating, by mass percentage, are as follows: waterborne polyurethane dispersion 70-85wt%, modified filler 2-5wt%, deionized water 8-15wt%, waterborne defoamer 0.1-0.5wt%, waterborne polyether siloxane leveling agent 0.1-0.5wt%, waterborne acetylenol wetting agent 0.1-0.5wt%, waterborne oxidized polyethylene wax lotus leaf hydrophobic agent 0.5-2wt%, waterborne film-forming aid 3-8wt%, waterborne associative polyurethane thickener 1-2wt%, and pH adjuster 0.3-0.5wt%.

2. The method for preparing a superhydrophobic, wear-resistant, water-based peelable coating according to claim 1, characterized in that, Step (1) includes at least one of the following features: The diol is a polycarbonate diol; The diisocyanate is isophorone diisocyanate; Diols are heated to 100-110°C. The vacuum dehydration time is 1-2 hours; The temperature for cooling is 45-55℃; The heating reaction is carried out at a temperature of 85-95℃ for 1-2 hours.

3. The method for preparing a superhydrophobic, wear-resistant, water-based peelable coating according to claim 1, characterized in that, In step (2), the preparation process of the waterborne polyurethane dispersion is as follows: anionic aminoalkyl sulfonate containing hydrophilic groups is added to the waterborne polyurethane prepolymer as a chain extender, the reaction continues, the R value is adjusted, and an active diluent is added. When the reaction system reaches the theoretical content of chemical bond NCO groups, the temperature is lowered, and a salting agent is added to the reaction system. Deionized water is added under stirring conditions to adjust the solid content.

4. The method for preparing a superhydrophobic, wear-resistant, water-based peelable coating according to claim 3, characterized in that, The preparation of waterborne polyurethane dispersions includes at least one of the following characteristics: The active diluent is N-ethylpyrrolidone; The salt-forming agent is triethylamine; The continued reaction time is 4-6 hours; The solid content of the aqueous polyurethane dispersion is 35-40%.

5. The method for preparing a superhydrophobic, wear-resistant, water-based peelable coating according to claim 3, characterized in that, The method for preparing the modified filler includes the following steps: S1: Acidify carbon nanotubes to obtain acidified carbon nanotubes. Add the acidified carbon nanotubes to an aqueous solution of tetraethyl orthosilicate, then add hydrochloric acid solution, stir and mix, add dibutyltin dilaurate and continue stirring, finally add polydimethylsiloxane, mix again, then filter and collect the filtered precipitate. S2: Polycaprolactone and epoxy resin are dissolved in ethyl acetate to obtain a suspension. The filtered precipitate is added to the suspension, ultrasonically treated, filtered, and the filtered solid is dried to obtain the modified filler.

6. The method for preparing a superhydrophobic, wear-resistant, water-based peelable coating according to claim 5, characterized in that, In step S1, the acidification treatment conditions include at least one of the following characteristics: Acidification treatment uses a nitric acid solution with a concentration of 0.1-0.2 mol / L; During acidification treatment, the mass ratio of carbon nanotubes to solution was (0.05-0.1):1000; The acidification treatment temperature is 100-110℃, and the treatment time is 30-60 minutes; The concentration of the tetraethyl orthosilicate aqueous solution is 3-4 mol / L, and the mass ratio of the acidified carbon nanotubes to the tetraethyl orthosilicate aqueous solution is (0.1-0.5):1; The concentration of the hydrochloric acid solution is 0.1-0.2 mol / L, and the volume ratio of the hydrochloric acid solution to the tetraethyl orthosilicate aqueous solution is (0.05-0.1):1; The volume ratio of dibutyltin dilaurate to polydimethylsiloxane is 1:(2-4), and the molar ratio of polydimethylsiloxane to tetraethyl orthosilicate is (0.1-0.5):1; The stirring and mixing temperature is 30℃, the time is 1-2 hours, and the stirring speed is 400-500 rpm; the continued stirring time is 10-20 minutes; and the remixing time is 10-20 minutes.

7. The method for preparing a superhydrophobic, wear-resistant, water-based peelable coating according to claim 5, characterized in that, S2 includes at least one of the following features: In the suspension, the concentrations of polycaprolactone and epoxy resin are 0.02-0.03 g / ml and 0.007-0.008 g / ml, respectively; the mass ratio of the filtered precipitate to the suspension is 1:(0.01-0.03). The ultrasonic treatment power is 400-500W, and the ultrasonic treatment time is 1-2 hours.

8. The method for preparing a superhydrophobic, wear-resistant, water-based peelable coating according to claim 1, characterized in that, The hydrophobic agent is a lotus leaf hydrophobic agent; the water-based defoamer is one or a mixture of water-based polyether siloxane defoamers, water-based mineral oil defoamers, and water-based polymer polyether defoamers; the water-based leveling agent is a water-based polyether siloxane leveling agent; the water-based wetting agent is a water-based acetylsene glycol wetting agent; the water-based film-forming aid is one of dipropylene glycol butyl ether and dipropylene glycol phenyl ether; the thickener is a water-based associative polyurethane thickener; and the pH adjuster is dimethylethanolamine.

9. The method for preparing a superhydrophobic, wear-resistant, water-based peelable coating according to claim 1, characterized in that, The coating also incorporates pigments and fillers to replace part of the waterborne polyurethane dispersion. The mass ratio of pigments and fillers to waterborne polyurethane dispersion is (1-5):5, and the total amount of pigments and fillers and waterborne polyurethane dispersion added is 70-85 wt% of the coating mass. The pigments and fillers include composite high abrasion-resistant texture powder, 1250-mesh silica powder, rutile titanium dioxide, medium-pigment carbon black powder, bentonite, and polyamide paste. The mass ratio of the composite high abrasion-resistant texture powder, 1250-mesh silica powder, rutile titanium dioxide, medium-pigment carbon black powder, bentonite, and polyamide paste is 5-8:10-15:10-12:0.2-0.5:1-2:1-2.

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