A super-hydrophobic coating for anti-scaling and anti-corrosion of metal substrates and preparation method thereof

Abstract

The invention belongs to the technical field of metal material anti-corrosion, and specifically relates to a super-hydrophobic coating for metal substrates to prevent scaling and corrosion, and a preparation method thereof. The invention adopts an ultrasonic dispersion method to prepare a nanoparticle hydrophobic modifier, and the uniformly dispersed hydrophobic modifier is used to prepare an aqueous polyurethane emulsion through an in-situ polymerization method. The aqueous polyurethane emulsion is uniformly mixed with a curing agent and then coated on the metal substrate through a coating method to obtain a nanoparticle-modified aqueous polyurethane emulsion coating. The anti-scaling and anti-corrosion super-hydrophobic coating prepared by the invention has good hydrophobicity, chemical stability and anti-scaling and anti-corrosion performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal material anti-corrosion, and specifically relates to a super-hydrophobic coating for anti-scaling and anti-corrosion of a metal substrate and a preparation method thereof. Background Art

[0002] In modern industrial applications, metals remain one of the most common engineering materials due to their excellent mechanical properties and wide range of applications. However, the corrosion problem faced by metals during practical use remains a major challenge that needs to be addressed. Corrosion not only reduces metal strength but can even lead to structural failure, resulting in significant economic losses and resource waste. Corrosion is particularly serious for metals exposed to harsh environments such as those containing moisture, acidity, alkalinity, or salt.

[0003] To address the corrosion problem of metal materials, many traditional anti-corrosion measures have emerged. Among them, organic coatings, a widely used anti-corrosion protection measure, have become an important technical means in the field due to their simple application, low cost, and excellent performance. Common organic coating materials include epoxy resin coatings, polyurethane coatings, and acrylic coatings. They form a physical barrier on the metal surface, isolating it from external moisture, oxygen, and harmful chemicals, thereby preventing metal corrosion.

[0004] However, despite their significant advantages in corrosion protection, organic coatings still face some significant challenges during use. In particular, when the coating is subjected to external stress, mechanical damage, chemical corrosion, or environmental factors, microcracks or peeling may occur on the coating surface. These microcracks not only affect the coating's appearance and structural integrity, but can also accelerate coating shedding, further exposing the metal surface and causing direct contact with corrosive media, thereby accelerating the onset of metal corrosion. Especially in complex or harsh working environments, the degradation of the coating's performance can exacerbate the corrosion rate of the metal substrate, resulting in even more severe economic losses.

[0005] To address this problem, the introduction of nanomaterials in recent years has provided new ideas and solutions for improving the performance of organic coatings. By adding nanoparticles or nanofillers to the coating, the various properties of the coating can be significantly improved, especially the hydrophobicity, crack resistance and chemical corrosion resistance of the coating. Nanomaterials have a higher specific surface area and unique physical and chemical properties than ordinary materials, which can effectively enhance the crack resistance and corrosion resistance of the coating. For example, nano-alumina, nano-silica, nano-carbon materials, etc. are often used as additives for coatings. These materials can enhance the hardness, wear resistance and chemical corrosion resistance of the coating, thereby improving the stability and durability of the coating in harsh environments.

[0006] As an emerging environmentally friendly coating material in recent years, waterborne polyurethane coatings have gradually become an important choice for metal surface coatings due to their excellent chemical stability, environmental friendliness, and good applicability. Waterborne polyurethane coatings not only effectively address the environmental pollution issues of traditional solvent-based coatings, but also exhibit excellent corrosion resistance and UV resistance, making them widely used in various fields such as automobiles, construction, and ships. However, in practical applications, waterborne polyurethane coatings still face the need for performance improvements, especially in terms of crack resistance, water resistance, and chemical corrosion resistance, which urgently need further improvement. Summary of the Invention

[0007] The purpose of the present invention is to provide a super hydrophobic coating for metal substrate anti-scaling and anti-corrosion and a preparation method thereof, so as to solve the problems in the prior art. The super hydrophobic coating prepared by the present invention has good hydrophobicity, chemical stability and anti-scaling and anti-corrosion performance.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing an anti-fouling and anti-corrosion super-hydrophobic coating for a metal substrate, comprising the following steps:

[0010] By mass percentage, 45% to 65% of a polyol and 5% to 15% of a polyisocyanate are mixed, and the mixture is stirred to obtain an NCO-terminated prepolymer; a nanoparticle hydrophobic modifier and a corrosion inhibitor having a total amount of 2% to 5% are added to the NCO-terminated prepolymer, and the mixture is stirred to obtain a mixed material; 2% to 6% of a hydrophilic chain extender is added to the mixture, and the mixture is stirred to obtain a hydrophilic chain extension mixed material; 1% to 5% of a neutralizer is added to the hydrophilic chain extension mixed material, and the mixture is stirred to obtain a neutralized mixed material; 4% to 45% of water is added to the neutralized mixed material, and the mixture is stirred to obtain an aqueous polyurethane emulsion; after uniformly mixing the aqueous polyurethane emulsion and a curing agent, the mixture is applied to the surface of a metal substrate, and after curing, an anti-scaling and anti-corrosion super-hydrophobic coating is obtained;

[0011] The mass ratio of the nanoparticle hydrophobic modifier to the corrosion inhibitor is 3:7; the mass ratio of the aqueous polyurethane emulsion to the curing agent is (5-20):1.

[0012] Preferably, the polyol is one or more of polypropylene glycol, polyether triol, propylene oxide copolymer glycol and polyethylene glycol.

[0013] Preferably, the polyisocyanate is one or more of diphenylmethane diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate and toluene diisocyanate.

[0014] Preferably, the nanoparticle hydrophobic modifier is one or more of nanoparticle-modified aminosilicone oil, nanoparticle-modified polydimethylsiloxane, nanoparticle-modified octadecylamine and nanoparticle-modified polyoxypropylenediamine.

[0015] Preferably, the preparation method of the nanoparticle hydrophobic modifier is as follows: a nanoparticle precursor, sodium hydroxide and ethanol are uniformly mixed to obtain a sol, dilute hydrochloric acid is added to hydrolyze and condense at 40-60°C to generate silica gel; the silica gel is solidified, calcined and dried to obtain nanoparticles; the nanoparticles and the hydrophobic agent are uniformly dispersed in water to form an oil-in-water system, and the reaction is carried out at 50-90°C for 2-5 hours to obtain the nanoparticle-modified hydrophobic agent.

[0016] Preferably, the corrosion inhibitor is one or more of cyclohexylamine, polyaniline, diethylenetriamine and hexadecyltrimethylammonium bromide.

[0017] Preferably, the hydrophilic chain extender is one or more of dimethylol propionic acid, dimethylol butyric acid, 1,2-propylene glycol-3-sodium sulfonate and 1,4-butanediol-2-sodium sulfonate.

[0018] Preferably, the neutralizing agent is one or more of triethylamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylaminoethyl methacrylate and isooctyl p-N,N-dimethylaminobenzoate.

[0019] Preferably, the curing agent is one or more of ethylenetriamine, diaminocyclohexane, isophoronediamine, diethylaminopropylamine and dimethylaminopropylamine.

[0020] In a second aspect, the present invention provides a super hydrophobic coating for anti-scaling and anti-corrosion of metal substrates.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention, through the reaction of polyols and polyisocyanates, combined with nanoparticle modification technology, can form a microscopic hydrophobic structure on the coating surface, so that the coating exhibits extremely low surface energy, water droplets cannot stay on the surface and roll off quickly, thereby showing excellent super-hydrophobic properties; by adopting water-based polyurethane emulsion, the environmental pollution problems caused by traditional solvent-based coatings are avoided, meeting the requirements of green environmental protection. By optimizing components such as hydrophilic chain extenders and neutralizers, the coating can maintain excellent chemical stability and mechanical strength during long-term use, avoiding early aging or peeling of the coating, and having a long service life.

[0023] Furthermore, the present invention adopts an ultrasonic dispersion method to prepare a nanoparticle hydrophobic modifier, and the evenly dispersed hydrophobic modifier is prepared by an in-situ polymerization method to obtain an aqueous polyurethane emulsion, which is evenly mixed with a curing agent and then coated on a metal substrate by a coating method to obtain a nanoparticle-modified aqueous polyurethane emulsion coating, which not only has super-hydrophobic and erosion-resistant properties, but also can enhance the anti-scaling and anti-corrosion properties of the metal substrate, giving it broad application prospects in the field of metal material corrosion protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is the contact angle data result diagram of the metal substrate not coated with water-based polyurethane emulsion coating and the metal substrate coated with water-based polyurethane emulsion coating. DETAILED DESCRIPTION

[0026] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0027] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0028] All features, such as values, amounts, contents, and concentrations, described herein as numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0029] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0030] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0031] The present invention is described in further detail below with reference to the accompanying drawings:

[0032] The first object of the present invention is to provide a method for preparing an anti-fouling and anti-corrosion super-hydrophobic coating for a metal substrate, comprising the following steps:

[0033] Mix 45% to 65% polyol and 5% to 15% polyisocyanate by mass and stir at 45°C to 85°C for 0.5 to 2.5 hours to produce an -NCO-terminated prepolymer. The polyol and polyisocyanate react to form a capped prepolymer with isocyanate (-NCO) groups. This prepolymer provides reactive groups for subsequent reactions, paving the way for crosslinking and curing the coating. Furthermore, the introduction of the -NCO-terminated prepolymer ensures the formation of a structurally stable polyurethane network in the coating.

[0034] A nanoparticle precursor, sodium hydroxide and ethanol are uniformly mixed to obtain a sol, which is then hydrolyzed and condensed with dilute hydrochloric acid at 60°C to generate silica gel; the silica gel is solidified, calcined and dried to obtain nanoparticles; the nanoparticles and a hydrophobic agent are uniformly dispersed in water, and a water-in-oil system is formed by chemical reaction between the hydroxyl groups on the surface of the nanoparticles and the amino groups on the hydrophobic agent, which is reacted at 50-90°C for 2-5 hours to obtain a nanoparticle-modified hydrophobic agent; a nanoparticle hydrophobic modifier and a corrosion inhibitor in a total amount of 2%-5% are added to an -NCO-terminated prepolymer, and the mixture is stirred at 45-85°C for 0.5-2.5 hours to obtain a mixture; nanoparticles with good hydrophobicity can be prepared by a sol-gel reaction of the nanoparticles and the hydrophobic agent. These nanoparticles can effectively enhance the surface hydrophobicity of the coating. When combined with a hydrophobic agent, they can form a micron- or even nanometer-scale rough structure on the coating surface, allowing water droplets to form a higher contact angle, thereby achieving a super-hydrophobic effect. By adding corrosion inhibitors, the metal substrate can not only be protected from corrosion, but the service life of the coating can also be extended, especially for metal materials exposed to harsh environments.

[0035] Add 2% to 6% of a hydrophilic chain extender to the mixture and stir at 45°C to 85°C for 1 to 3 hours to produce a hydrophilic chain-extended mixture. Hydrophilic chain extenders contain molecules with hydrophilic groups, which improve the hydrophilicity of the coating and enhance its dispersibility and adhesion. During the coating formation process, the presence of hydrophilic groups optimizes intermolecular interactions, resulting in a more uniform coating structure and contributing to its stability and adhesion.

[0036] 1% to 5% of a neutralizing agent is added to the hydrophilic chain extension mixture, and the mixture is stirred at 30°C to 70°C for 0.5h to 2.5h to obtain a neutralized mixture. The neutralizing agent reacts the active groups (e.g., -NCO) in the coating with the acidic substance, so that the -NCO groups in the prepolymer are converted into other chemical structures, avoiding overreaction or incomplete reaction, thereby ensuring the ultimate stability and film-forming properties of the coating.

[0037] Add 4% to 45% water to the neutralized mixture and stir for 1 to 3 hours at 20°C to 60°C to produce a waterborne polyurethane emulsion. This emulsion is more environmentally friendly than solvent-based coatings and exhibits better rheological properties, which helps ensure uniform coating application and mitigates the environmental and human hazards of solvents. Furthermore, the dispersed particles in the emulsion promote rapid film formation.

[0038] After uniformly mixing a water-based polyurethane emulsion and a curing agent, the mixture is applied to the metal substrate and cured at 20°C to 50°C for 0.5 to 2.5 hours to create a super-hydrophobic coating that is both anti-fouling and anti-corrosion. The curing agent creates a three-dimensional network between the polyurethane molecules, thereby enhancing the coating's mechanical strength, durability, and weather resistance.

[0039] The mass ratio of the nanoparticle hydrophobic modifier to the corrosion inhibitor is 3:7; the mass ratio of the aqueous polyurethane emulsion to the curing agent is (5-20):1.

[0040] The polyol is one or more of polypropylene glycol, polyether triol, propylene oxide copolymer glycol, and polyethylene glycol. Polyethylene glycol and polypropylene glycol have good solubility, which can reduce the viscosity of the polyurethane and improve its processing performance. Propylene oxide copolymer glycol has strong chemical resistance, which can improve the coating's corrosion resistance to chemicals such as acids, bases, and salts.

[0041] The polyisocyanate is one or more of diphenylmethane diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, and toluene diisocyanate. Diphenylmethane diisocyanate has high strength, hardness, durability, and low thermal conductivity, effectively improving energy efficiency and reducing energy consumption. Isocyanate has excellent UV resistance. 1,6-hexamethylene diisocyanate has good abrasion resistance, tension resistance, and tear resistance. Toluene diisocyanate has good elasticity and softness.

[0042] The nanoparticle hydrophobic modifier is one or more of nanoparticle-modified aminosilicone oil, nanoparticle-modified polydimethylsiloxane, nanoparticle-modified octadecylamine, and nanoparticle-modified polyoxypropylenediamine. Nanoparticle hydrophobic modifiers are formed by combining nanoparticles with different hydrophobic substances (such as aminosilicone oil, polydimethylsiloxane, octadecylamine, and polyoxypropylenediamine). These modifications significantly enhance the hydrophobic properties of a material or surface, specifically improving its water repellency or water droplet rollability.

[0043] The corrosion inhibitor is one or more of cyclohexylamine, polyaniline, diethylenetriamine, and cetyltrimethylammonium bromide. Cyclohexylamine chemically adsorbs onto metal surfaces through its amine groups, forming a protective film that reduces the metal's corrosion rate. Polyaniline, with its electrical conductivity and self-healing properties, provides long-lasting electrochemical protection, extending the metal's corrosion resistance. Diethylenetriamine coordinates with the metal surface through multiple nitrogen atoms, forming a stable protective layer that exhibits excellent corrosion inhibition, particularly in acidic environments. The long-chain alkyl groups of cetyltrimethylammonium bromide adsorb onto metal surfaces, forming a hydrophobic protective film that enhances the metal's salt and corrosion resistance.

[0044] The hydrophilic chain extender is one or more of dimethylolpropionic acid, dimethylolbutyric acid, 1,2-propylene glycol-3-sodium sulfonate, and 1,4-butanediol-2-sodium sulfonate. Dimethylolpropionic acid, by introducing hydroxyl and methyl groups, enhances the hydrophilicity and polarity between molecules, improving the water solubility and dispersibility of the polymer. Dimethylolbutyric acid provides stronger hydrophilicity and steric effects between molecules, improving the hydrophilicity and fluidity of the polymer. Sodium 1,2-propylene glycol-3-sulfonate introduces strong hydrophilicity through the sulfonic acid group, increasing the water solubility and dispersion stability of the polymer and enhancing its performance in aqueous systems. Sodium 1,4-butanediol-2-sulfonate enhances water dispersibility through the sulfonic acid group, helping to improve the polymer's ability to disperse and dissolve in water, thereby improving the stability and processability of the product.

[0045] The neutralizing agent is one or more of triethylamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylaminoethyl methacrylate and 2-ethylhexyl para-N,N-dimethylaminobenzoate. Triethylamine neutralizes acidic substances through alkaline action, stabilizes the pH value of the system, reduces acidic corrosion, and improves the stability of the system; triethanolamine can effectively adjust the pH of the solution, improve the stability of the solvent and enhance the anti-corrosion effect. N-methyldiethanolamine enhances the corrosion inhibition of the solution through the alkaline neutralization effect of its nitrogen base; N,N-dimethylaminoethyl methacrylate provides a strong neutralizing effect through the chemical reaction between its amino group and methacrylic acid, improving the reactivity and anti-corrosion performance of the system; the amino structure of 2-ethylhexyl para-N,N-dimethylaminobenzoate can effectively adjust the acid-base balance of the solution and enhance the anti-corrosion and dispersibility of the system.

[0046] The curing agent is one or more of vinyltriamine, diaminocyclohexane, isophoronediamine, diethylaminopropylamine, and dimethylaminopropylamine. Ethyltriamine has strong crosslinking ability and can provide high hardness and strength. The cyclic structure of diaminocyclohexane enhances stability and has excellent chemical and weather resistance. Isophoronediamine is highly reactive and can cure quickly, providing good heat and chemical resistance. Diethylaminopropylamine can provide good heat resistance and mechanical properties. Dimethylaminopropylamine has fast curing characteristics and can provide high mechanical strength and heat resistance.

[0047] The invention adopts an in-situ polymerization method to prepare an aqueous polyurethane emulsion, mixes the mixture evenly with a curing agent, and uses polydopamine as an adhesive to coat the emulsion on a metal substrate to obtain an anti-scaling and anti-corrosion super-hydrophobic coating. The prepared anti-scaling and anti-corrosion super-hydrophobic coating for the metal substrate has good hydrophobicity, chemical stability and anti-scaling and anti-corrosion performance.

[0048] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0049] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" represents weight percentage, "%" represents weight %, and "ratio" represents weight ratio.

[0050] Example 1

[0051] The following raw materials were weighed in percentage by mass: polypropylene glycol 45%, diphenylmethane diisocyanate 5%, nanoparticle-modified amino silicone oil 0.6%, cyclohexylamine 1.4%, dimethylolpropionic acid 2%, triethylamine 1%, and water 45%;

[0052] The weighed polypropylene glycol was added to diphenylmethane diisocyanate and stirred at 45°C for 0.5 h to obtain an -NCO-terminated prepolymer;

[0053] The weighed nanoparticle-modified amino silicone oil and cyclohexylamine were added to the -NCO-terminated prepolymer, and stirred at 45° C. for 0.5 h to obtain a mixture;

[0054] The weighed dimethylolpropionic acid was added to the mixture, and stirred at 45° C. for 1 hour to obtain a hydrophilic chain-extended mixture;

[0055] The weighed triethylamine was added to the hydrophilic chain extension mixture, and stirred at 30°C for 0.5h to obtain a neutralized mixture;

[0056] The weighed water was added to the neutralized mixture, and stirred at 20° C. for 1 h to obtain a waterborne polyurethane emulsion;

[0057] The obtained aqueous polyurethane emulsion and ethylenetriamine were evenly mixed in a mass ratio of 5:1, and cured at 20°C for 0.5h to obtain an anti-fouling and anti-corrosion super-hydrophobic coating for a metal substrate.

[0058] Example 2

[0059] The following raw materials were weighed according to mass percentage: polyether triol 55%, isophorone diisocyanate 8%, nanoparticle modified polydimethylsiloxane 0.9%, polyaniline 2.1%, dimethylolbutyric acid 3%, triethanolamine 2%, water 29%;

[0060] The weighed polyether triol was added to isophorone diisocyanate and stirred at 55°C for 1 hour to obtain an -NCO-terminated prepolymer;

[0061] The weighed nanoparticle-modified polydimethylsiloxane and polyaniline were added to the -NCO-terminated prepolymer, and stirred at 55° C. for 1 h to obtain a mixture;

[0062] The weighed dimethylolbutyric acid was added to the mixture, and stirred at 55° C. for 1.5 h to obtain a hydrophilic chain-extended mixture;

[0063] The weighed triethanolamine was added to the hydrophilic chain extension mixture, and stirred at 40° C. for 1 h to obtain a neutralized mixture;

[0064] The weighed water was added to the neutralized mixture, and the mixture was stirred at high speed at 30° C. for 1.5 h to obtain a waterborne polyurethane emulsion;

[0065] The obtained aqueous polyurethane emulsion and diaminocyclohexane were evenly mixed in a mass ratio of 10:1, and cured at 30°C for 1 hour to obtain an anti-fouling and anti-corrosion super-hydrophobic coating for a metal substrate.

[0066] Example 3

[0067] The following raw materials were weighed according to mass percentage: 65% propylene oxide copolymer glycol, 10% 1,6-hexamethylene diisocyanate, 1.2% nanoparticle-modified octadecylamine, 2.8% diethylenetriamine, 4% sodium 1,2-propylene glycol-3-sulfonate, 3% N-methyldiethanolamine, and 14% water;

[0068] The weighed propylene oxide copolymer glycol was added to 1,6-hexamethylene diisocyanate and stirred at 65°C for 1.5 hours to obtain an -NCO-terminated prepolymer;

[0069] The weighed nanoparticle-modified octadecylamine and diethylenetriamine were added to the -NCO-terminated prepolymer, and stirred at 65° C. for 1.5 h to obtain a mixture;

[0070] The weighed sodium 1,2-propylene glycol-3-sulfonate was added to the mixture, and stirred at 65° C. for 2 h to obtain a hydrophilic chain-extended mixture;

[0071] The weighed N-methyldiethanolamine was added to the hydrophilic chain extension mixture, and stirred at 50° C. for 1.5 h to obtain a neutralized mixture;

[0072] The weighed water was added to the neutralized mixture, and the mixture was stirred at high speed at 40° C. for 2 h to obtain a waterborne polyurethane emulsion;

[0073] The obtained aqueous polyurethane emulsion and isophorone diamine were evenly mixed in a mass ratio of 15:1, and cured at 40°C for 1.5h to obtain an anti-fouling and anti-corrosion super-hydrophobic coating for a metal substrate.

[0074] Example 4

[0075] The following raw materials were weighed in percentage by mass: polyethylene glycol 55%, toluene diisocyanate 12%, nanoparticle-modified polyoxypropylene diamine 1.5%, hexadecyltrimethylammonium bromide 3.5%, sodium 1,4-butanediol-2-sulfonate 5%, N,N-dimethylaminoethyl methacrylate 4%, and water 19%;

[0076] The weighed polyethylene glycol was added to toluene diisocyanate and stirred at 75°C for 2 h to obtain an -NCO-terminated prepolymer;

[0077] The weighed nanoparticle-modified polyoxypropylene diamine and hexadecyltrimethylammonium bromide were added to the -NCO-terminated prepolymer, and stirred at 75° C. for 2 h to obtain a mixture;

[0078] The weighed sodium 1,4-butanediol-2-sulfonate was added to the mixture, and stirred at 75° C. for 2.5 h to obtain a hydrophilic chain-extended mixture;

[0079] The weighed N,N-dimethylaminoethyl methacrylate was added to the hydrophilic chain extension mixture, and stirred at 50° C. for 2 h to obtain a neutralized mixture;

[0080] The weighed water was added to the neutralized mixture, and the mixture was stirred at high speed at 60° C. for 2.5 h to obtain a waterborne polyurethane emulsion;

[0081] The obtained aqueous polyurethane emulsion and diethylaminopropylamine were evenly mixed in a mass ratio of 20:1, and cured at 50°C for 2h to obtain an anti-fouling and anti-corrosion super-hydrophobic coating for a metal substrate.

[0082] Example 5

[0083] Weigh the following raw materials according to mass percentage:

[0084] Polyether triol 55%, toluene diisocyanate 10%, nanoparticle modified polydimethylsiloxane 0.9%, polyaniline 2.1%, dimethylolbutyric acid 3%, 2-ethylhexyl 4-N,N-dimethylaminobenzoate 3%, water 26%;

[0085] The weighed polyether triol was added to isophorone diisocyanate and stirred at 85°C for 2.5 hours to obtain an -NCO-terminated prepolymer;

[0086] The weighed nanoparticle-modified polydimethylsiloxane and polyaniline were added to the -NCO-terminated prepolymer, and stirred at 85° C. for 2.5 h to obtain a mixture;

[0087] The weighed dimethylolbutyric acid was added to the mixture, and stirred at 85° C. for 3 h to obtain a hydrophilic chain-extended mixture;

[0088] Add the weighed isooctyl p-N,N-dimethylaminobenzoate to the hydrophilic chain extension mixture, and stir at 70° C. for 2.5 h to obtain a neutralized mixture;

[0089] The weighed water was added to the neutralized mixture, and the mixture was stirred at high speed at 60° C. for 3 h to obtain a waterborne polyurethane emulsion;

[0090] The obtained aqueous polyurethane emulsion and dimethylaminopropylamine were evenly mixed in a mass ratio of 10:1, and cured at 50°C for 2.5 hours to obtain an anti-fouling and anti-corrosion super-hydrophobic coating for a metal substrate.

[0091] Example 6

[0092] Weigh the following raw materials according to mass percentage:

[0093] A mixture of polypropylene glycol and polyether triol 55%, a mixture of diphenylmethane diisocyanate and isophorone diisocyanate 15%, a mixture of nanoparticle-modified amino silicone oil and nanoparticle-modified polydimethylsiloxane 0.9%, a mixture of cyclohexylamine and polyaniline 2.1%, a mixture of dimethylolpropionic acid and dimethylolbutyric acid 6%, a mixture of triethylamine and triethanolamine 5%, and water 16%;

[0094] The weighed mixture of polypropylene glycol and polyether triol was added to the mixture of diphenylmethane diisocyanate and isophorone diisocyanate, and stirred at 85° C. for 2.5 h to obtain an -NCO-terminated prepolymer;

[0095] A mixture of nanoparticle-modified aminosilicone oil and nanoparticle-modified polydimethylsiloxane and a mixture of cyclohexylamine and polyaniline were added to the -NCO-terminated prepolymer, and stirred at 85° C. for 2.5 h to obtain a mixed material;

[0096] Adding the weighed mixture of dimethylolpropionic acid and dimethylolbutanoic acid to the mixed material, stirring at 85° C. for 3 hours to obtain a hydrophilic chain-extended mixed material;

[0097] Add the weighed mixture of triethylamine and triethanolamine to the hydrophilic chain extension mixture, and stir at 70° C. for 2.5 hours to obtain a neutralized mixture;

[0098] The weighed water was added to the neutralized mixture, and the mixture was stirred at high speed at 60° C. for 3 h to obtain a waterborne polyurethane emulsion;

[0099] The obtained aqueous polyurethane emulsion was evenly mixed with a mixture of vinyltriamine and diaminocyclohexane in a mass ratio of 10:1, and cured at 50° C. for 2.5 h to obtain an anti-fouling and anti-corrosion super-hydrophobic coating for a metal substrate.

[0100] Example 7

[0101] Weigh the following raw materials according to mass percentage:

[0102] A mixture of polypropylene glycol, polyether triol, propylene oxide copolymer glycol and polyethylene glycol (65%), a mixture of diphenylmethane diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate and toluene diisocyanate (15%), a mixture of nanoparticle-modified aminosilicone oil, nanoparticle-modified polydimethylsiloxane, nanoparticle-modified octadecylamine and nanoparticle-modified polyoxypropylenediamine (1.5%), a mixture of cyclohexylamine, polyaniline, diethylenetriamine and hexadecyltrimethylammonium bromide (3.5%), a mixture of dimethylolpropionic acid, dimethylolbutyric acid, sodium 1,2-propylene glycol-3-sulfonate and sodium 1,4-butanediol-2-sulfonate (6%), a mixture of triethylamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylaminoethyl methacrylate and isooctyl p-N,N-dimethylaminobenzoate (5%), and water (4%).

[0103] A mixture of weighed polypropylene glycol, polyether triol, propylene oxide copolymer glycol and polyethylene glycol was added to a mixture of diphenylmethane diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate and toluene diisocyanate, and stirred at 85° C. for 2.5 h to obtain an -NCO-terminated prepolymer;

[0104] A mixture of nanoparticle-modified aminosilicone oil, nanoparticle-modified polydimethylsiloxane, nanoparticle-modified octadecylamine, and nanoparticle-modified polyoxypropylenediamine, and a mixture of cyclohexylamine, polyaniline, diethylenetriamine, and hexadecyltrimethylammonium bromide were added to an -NCO-terminated prepolymer, and the mixture was stirred at 85° C. for 2.5 h to obtain a mixture.

[0105] Adding a mixture of weighed dimethylolpropionic acid, dimethylolbutanoic acid, 1,2-propylene glycol-3-sulfonate sodium and 1,4-butanediol-2-sulfonate sodium to the mixed material, stirring at 85° C. for 3 h to obtain a hydrophilic chain-extended mixed material;

[0106] A mixture of triethylamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylaminoethyl methacrylate and isooctyl p-N,N-dimethylaminobenzoate was added to the hydrophilic chain extension mixture, and stirred at 70° C. for 2.5 hours to obtain a neutralized mixture;

[0107] The weighed water was added to the neutralized mixture, and the mixture was stirred at high speed at 60° C. for 3 h to obtain a waterborne polyurethane emulsion;

[0108] The obtained aqueous polyurethane emulsion was evenly mixed with a mixture of vinyltriamine, diaminocyclohexane, isophoronediamine, diethylaminopropylamine and dimethylaminopropylamine in a mass ratio of 10:1, and cured at 50°C for 2.5h to obtain an anti-fouling and anti-corrosion super hydrophobic coating for a metal substrate.

[0109] like Figure 1 As shown, the contact angle of the metal substrate not coated with the aqueous polyurethane emulsion is 85°, while the contact angle of the metal substrate coated with the anti-fouling and anti-corrosion super-hydrophobic coating prepared in Example 1 of the present invention is 121°. In comparison, the metal substrate coated with the anti-fouling and anti-corrosion super-hydrophobic coating of the present invention has a better hydrophobic effect.

[0110] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a super-hydrophobic coating for anti-scaling and anti-corrosion of a metal substrate, characterized in that: The following steps are involved: By mass percentage, 45% to 65% of a polyol and 5% to 15% of a polyisocyanate are mixed, and the mixture is stirred to obtain an NCO-terminated prepolymer; a nanoparticle hydrophobic modifier and a corrosion inhibitor having a total amount of 2% to 5% are added to the NCO-terminated prepolymer, and the mixture is stirred to obtain a mixed material; 2% to 6% of a hydrophilic chain extender is added to the mixture, and the mixture is stirred to obtain a hydrophilic chain extension mixed material; 1% to 5% of a neutralizer is added to the hydrophilic chain extension mixed material, and the mixture is stirred to obtain a neutralized mixed material; 4% to 45% of water is added to the neutralized mixed material, and the mixture is stirred to obtain an aqueous polyurethane emulsion; after uniformly mixing the aqueous polyurethane emulsion and a curing agent, the mixture is applied to the surface of a metal substrate, and after curing, an anti-scaling and anti-corrosion super-hydrophobic coating is obtained; Wherein, the mass ratio of the nanoparticle hydrophobic modifier to the corrosion inhibitor is 3:7; the mass ratio of the aqueous polyurethane emulsion to the curing agent is (5-20):1; The nanoparticle hydrophobic modifier is one or more of nanoparticle-modified aminosilicone oil and nanoparticle-modified polyoxypropylenediamine; The preparation method of the nanoparticle hydrophobic modifier comprises: uniformly mixing a nanoparticle precursor, sodium hydroxide and ethanol to obtain a sol, adding dilute hydrochloric acid to hydrolyze and condense at 40-60° C. to generate silica gel; curing, calcining and drying the silica gel to obtain nanoparticles; uniformly mixing the nanoparticles and the hydrophobic agent and dispersing them in water to form an oil-in-water system, and reacting at 50-90° C. for 2-5 hours to obtain the nanoparticle-modified hydrophobic agent.

2. A method for preparing a metal substrate anti-scaling and anti-corrosion super-hydrophobic coating according to claim 1, characterized in that, The polyol is one or more of polypropylene glycol, polyether triol, propylene oxide copolymer glycol and polyethylene glycol.

3. A method for preparing a metal substrate anti-scaling and anti-corrosion super-hydrophobic coating according to claim 1, characterized in that, The polyisocyanate is one or more of diphenylmethane diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate and toluene diisocyanate.

4. A method for preparing a super-hydrophobic coating for metal substrate anti-scaling and anti-corrosion according to claim 1, characterized in that, The corrosion inhibitor is one or more of cyclohexylamine, polyaniline, diethylenetriamine and hexadecyltrimethylammonium bromide.

5. A method for preparing a super-hydrophobic coating for metal substrate anti-scaling and anti-corrosion according to claim 1, characterized in that, The hydrophilic chain extender is one or more of dimethylol propionic acid, dimethylol butyric acid, 1,2-propylene glycol-3-sodium sulfonate and 1,4-butanediol-2-sodium sulfonate.

6. A method for preparing an anti-scaling and anti-corrosion super-hydrophobic coating for a metal substrate according to claim 1, characterized in that, The neutralizing agent is one or more of triethylamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylaminoethyl methacrylate and isooctyl p-N,N-dimethylaminobenzoate.

7. A method for preparing an anti-scaling and anti-corrosion super-hydrophobic coating for a metal substrate according to claim 1, characterized in that, The curing agent is one or more of ethylenetriamine, diaminocyclohexane, isophoronediamine, diethylaminopropylamine and dimethylaminopropylamine.

8. A super hydrophobic coating for anti-scaling and anti-corrosion of metal substrates, characterized in that: The method is prepared according to any one of claims 1 to 7.

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