Super-hydrophobic coating for scale prevention and corrosion prevention of metal matrix and preparation method of super-hydrophobic coating

Abstract

The invention belongs to the technical field of corrosion prevention of metal materials, and particularly relates to a super-hydrophobic coating for scale prevention and corrosion prevention of a metal matrix and a preparation method of the super-hydrophobic coating. The preparation method comprises the following steps: preparing a nanoparticle hydrophobic modifier by adopting an ultrasonic dispersion method, preparing a waterborne polyurethane emulsion from the uniformly dispersed hydrophobic modifier by adopting an in-situ polymerization method, uniformly mixing the waterborne polyurethane emulsion with a curing agent, and coating the mixture on a metal matrix by adopting a coating method to obtain a nanoparticle modified waterborne polyurethane emulsion coating; the prepared anti-scale and anti-corrosion super-hydrophobic coating has good hydrophobicity, chemical stability and anti-scale and anti-corrosion performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal material anti-corrosion, and in particular 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, metal materials are still 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 in actual use is a major challenge that needs to be solved urgently. Corrosion not only causes the strength of metals to decrease, but can even lead to structural failure, causing huge economic losses and waste of resources to the project. Especially for metal materials exposed to harsh environments such as moisture, acidity, alkalinity or salt, the corrosion problem is particularly serious.

[0003] In order to solve the corrosion problem of metal materials, many traditional anti-corrosion measures have emerged. Among them, organic coatings, as a widely used anti-corrosion protection measure, have become an important technical means in the field of anti-corrosion due to their simple construction, low cost, and excellent performance. Common organic coating materials include epoxy resin coatings, polyurethane coatings, acrylic coatings, etc. They form a physical barrier on the metal surface to isolate external moisture, oxygen and harmful chemicals to prevent metal corrosion.

[0004] However, despite the significant advantages of organic coatings in terms of corrosion protection, they still face some challenges that are difficult to ignore 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 appearance and structural integrity of the coating, but may also accelerate the shedding of the coating, further exposing the metal surface, causing the metal surface to directly contact the corrosive medium, thereby accelerating the occurrence of metal corrosion. Especially in complex or harsh working environments, the performance degradation of the coating will increase the corrosion rate of the metal substrate, resulting in more serious economic losses.

[0005] In order to solve this problem, in recent years, the introduction of nanomaterials 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-silicon dioxide, 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 substrate surface coating materials due to their excellent chemical stability, environmental friendliness and good applicability. Waterborne polyurethane coatings can not only effectively solve the environmental pollution problem of traditional solvent-based coatings, but also have good corrosion resistance and UV resistance. They are widely used in many fields such as automobiles, construction, and ships. However, waterborne polyurethane coatings still face the need to improve performance in practical applications, 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 for metal substrate anti-scaling and anti-corrosion 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: In a first aspect, the present invention provides a method for preparing a super hydrophobic coating for metal substrate anti-fouling and anti-corrosion, comprising the following steps: By mass percentage, 45% to 65% of a polyol and 5% to 15% of a polyisocyanate are mixed, and stirred to react 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 stirred to react to obtain a mixed material; 2% to 6% of a hydrophilic chain extender is added to the mixed material, and stirred to react to obtain a hydrophilic chain extension mixed material; 1% to 5% of a neutralizer is added to the hydrophilic chain extension mixed material, and stirred to react to obtain a neutralized mixed material; 4% to 45% of water is added to the neutralized mixed material, and stirred to react to obtain an aqueous polyurethane emulsion; after the aqueous polyurethane emulsion and a curing agent are evenly mixed, they are 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 waterborne polyurethane emulsion to the curing agent is (5-20):1.

[0009] Preferably, the polyol is one or more of polypropylene glycol, polyether triol, propylene oxide copolymer glycol and polyethylene glycol.

[0010] Preferably, the polyisocyanate is one or more of diphenylmethane diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate and toluene diisocyanate.

[0011] Preferably, the nanoparticle hydrophobic modifier is one or more of nanoparticle-modified aminosilicone oil, nanoparticle-modified polydimethylsiloxane, nanoparticle-modified octadecylamine and nanoparticle-modified polyoxypropylenediamine.

[0012] Preferably, the preparation method of the nanoparticle hydrophobic modifier is: nanoparticle precursor, sodium hydroxide and ethanol are mixed evenly 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 mixed evenly and dispersed in water to form an oil-in-water system, and reacted at 50-90°C for 2-5h to obtain a nanoparticle-modified hydrophobic agent.

[0013] Preferably, the corrosion inhibitor is one or more of cyclohexylamine, polyaniline, diethylenetriamine and hexadecyltrimethylammonium bromide.

[0014] 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.

[0015] Preferably, the neutralizing agent is one or more of triethylamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylaminoethyl methacrylate and isooctyl p-N,N-dimethylaminobenzoate.

[0016] Preferably, the curing agent is one or more of vinyltriamine, diaminocyclohexane, isophoronediamine, diethylaminopropylamine and dimethylaminopropylamine.

[0017] In a second aspect, the present invention provides a super hydrophobic coating for anti-fouling and anti-corrosion of metal substrates.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention, through the reaction of polyol and polyisocyanate, combined with nanoparticle modification technology, can form a microscopic hydrophobic structure on the coating surface, so that the coating shows extremely low surface energy, water droplets cannot stay on the surface and roll off quickly, thereby showing excellent super-hydrophobic performance; by adopting water-based polyurethane emulsion, the environmental pollution problems caused by traditional solvent-based coatings are avoided, and the requirements of green environmental protection are met. 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.

[0019] Furthermore, the present invention adopts an ultrasonic dispersion method to prepare a nanoparticle hydrophobic modifier, and the uniformly 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-fouling and anti-corrosion properties of the metal substrate, so that it has broad application prospects in the field of metal material corrosion protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 This is a graph showing the contact angle data results for a metal substrate that is not coated with a waterborne polyurethane emulsion coating and a metal substrate that is coated with a waterborne polyurethane emulsion coating. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0023] 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.

[0024] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0025] In this document, unless otherwise specified, “includes,” “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.”

[0026] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0027] The present invention is further described in detail below in conjunction with the accompanying drawings: The first object of the present invention is to provide a method for preparing a super hydrophobic coating for metal substrate anti-fouling and anti-corrosion, comprising the following steps: By mass percentage, 45% to 65% of polyol and 5% to 15% of polyisocyanate are mixed, stirred at 45°C to 85°C for 0.5h to 2.5h to obtain -NCO-terminated prepolymer; polyol and polyisocyanate react to generate a blocked prepolymer with isocyanate (-NCO). The prepolymer provides active groups for subsequent reactions, laying the foundation for crosslinking and curing of the coating; at the same time, the introduction of -NCO-terminated prepolymer ensures that the coating can form a structurally stable polyurethane network in the later stage.

[0028] The nanoparticle precursor, sodium hydroxide and ethanol are uniformly mixed to obtain a sol, and diluted hydrochloric acid is added to hydrolyze and condense at 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, and the hydroxyl groups on the surface of the nanoparticles and the amino groups on the hydrophobic agent are chemically reacted to form a water-in-oil system, and the reaction is carried out at 50-90°C for 2-5h to obtain a nanoparticle modified hydrophobic agent; a total of 2%-5% of the nanoparticle hydrophobic modifier and the corrosion inhibitor are added to the -NCO-terminated prepolymer, and the mixture is reacted at 45°C-85°C for 0.5h-2.5h to obtain a mixed material; 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 the nanoparticles are combined with the hydrophobic agent, they can form a micron-scale or even nano-scale rough structure on the surface of the coating, so that the water droplets form a higher contact angle, thereby achieving a super-hydrophobic effect. By adding corrosion inhibitors, it is not only possible to protect the metal substrate from corrosion, but also to extend the service life of the coating, especially for metal materials exposed to harsh environments.

[0029] 2% to 6% of the hydrophilic chain extender is added to the mixture, and the mixture is stirred at 45°C to 85°C for 1h to 3h to obtain a hydrophilic chain extended mixture; the hydrophilic chain extender has molecules with hydrophilic groups, which can improve the hydrophilicity of the coating and enhance the dispersibility and adhesion of the coating. During the coating formation process, the presence of the hydrophilic group can optimize the interaction between molecules, form a more uniform coating structure, and contribute to the stability and adhesion of the coating.

[0030] 1%~5% neutralizer is added to the hydrophilic chain extension mixture, and stirred at 30℃~70℃ for 0.5h~2.5h to obtain a neutralized mixture; the active groups (such as -NCO) in the coating are reacted with the acidic substance by the neutralizer, 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.

[0031] Add 4% to 45% water to the neutralized mixture, stir at 20℃ to 60℃ for 1h to 3h to obtain a waterborne polyurethane emulsion; waterborne emulsions are more environmentally friendly than solvent-based coatings and have better rheological properties, which helps to ensure uniformity of the coating during application and avoid the harm of solvents to the environment and human body. At the same time, the dispersed state of particles in the waterborne emulsion can promote the rapid film formation of the coating.

[0032] After the water-based polyurethane emulsion and curing agent are evenly mixed, they are applied to the surface of the metal substrate and cured at 20℃~50℃ for 0.5h~2.5h to obtain an anti-fouling and anti-corrosion super hydrophobic coating. The curing agent forms a three-dimensional network structure between the polyurethane molecules, thereby improving the mechanical strength, durability and weather resistance of the coating.

[0033] Wherein, the mass ratio of the nanoparticle hydrophobic modifier to the corrosion inhibitor is 3:7; the mass ratio of the waterborne polyurethane emulsion to the curing agent is (5-20):1.

[0034] The polyol is one or more of polypropylene glycol, polyether triol, oxypropylene copolymer glycol and polyethylene glycol. Polyethylene glycol and polypropylene glycol have good solubility, can reduce the viscosity of polyurethane and improve its processing performance. Oxypropylene copolymer glycol has strong chemical resistance and can improve the corrosion resistance of the coating to chemical substances such as acid, alkali and salt.

[0035] 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, and can effectively improve energy efficiency and reduce energy consumption; isophorone diisocyanate has excellent ultraviolet resistance; 1,6-hexamethylene diisocyanate has good wear resistance, tension resistance and tear resistance; toluene diisocyanate has good elasticity and softness.

[0036] The nanoparticle hydrophobic modifier is one or more of nanoparticle modified aminosilicone oil, nanoparticle modified polydimethylsiloxane, nanoparticle modified octadecylamine and nanoparticle modified polyoxypropylene diamine. The nanoparticle hydrophobic modifier is formed by combining nanoparticles with different hydrophobic substances (such as aminosilicone oil, polydimethylsiloxane, octadecylamine and polyoxypropylene diamine, etc.), and the modification can significantly improve the hydrophobic properties of the material or surface, that is, improve the surface's repellency to water or the rolling properties of water droplets.

[0037] The corrosion inhibitor is one or more of cyclohexylamine, polyaniline, diethylenetriamine and hexadecyltrimethylammonium bromide. Cyclohexylamine chemically adsorbs on the metal surface through its amine group to form a protective film, thereby reducing the metal corrosion rate; polyaniline provides long-term electrochemical protection and prolongs the corrosion resistance of the metal by virtue of its conductivity and self-healing properties. Diethylenetriamine coordinates with the metal surface through multiple nitrogen atoms to form a stable protective layer, which has a good corrosion inhibition effect, especially in an acidic environment; the long-chain alkyl of hexadecyltrimethylammonium bromide forms a hydrophobic protective film by adsorbing on the metal surface, thereby enhancing the salt resistance and corrosion resistance of the metal.

[0038] 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. Dimethylol propionic acid enhances the hydrophilicity and polarity between molecules by introducing hydroxyl and methyl groups, thereby improving the water solubility and dispersibility of the polymer; dimethylol butyric acid can provide stronger hydrophilicity and spatial effect between molecules, thereby improving the hydrophilicity and fluidity of the polymer; 1,2-propylene glycol-3-sodium sulfonate introduces strong hydrophilicity through sulfonic acid groups, thereby increasing the water solubility and dispersion stability of the polymer, thereby improving its performance in aqueous systems; 1,4-butanediol-2-sodium sulfonate enhances water dispersibility through sulfonic acid groups, thereby helping to improve the ability of the polymer to disperse and dissolve in water, thereby improving the stability and processability of the product.

[0039] The neutralizing agent is one or more of triethylamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylaminoethyl methacrylate and isooctyl 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 of its nitrogen base; N,N-dimethylaminoethyl methacrylate provides a strong neutralization effect through the chemical reaction of its amino group and methacrylic acid, improves the reactivity and anti-corrosion performance of the system; the amino structure of isooctyl N,N-dimethylaminobenzoate can effectively adjust the acid-base balance of the solution and enhance the anti-corrosion and dispersibility of the system.

[0040] The curing agent is one or more of vinyl triamine, diaminocyclohexane, isophorone diamine, diethylamino propylamine and dimethylamino propylamine. Vinyl triamine has strong cross-linking ability and can provide high hardness and strength; the cyclic structure of diamino cyclohexane enhances stability and has excellent chemical resistance and weather resistance; isophorone diamine has strong reactivity, can cure quickly, and provides good heat resistance and chemical resistance. Diethylamino propylamine can provide good heat resistance and mechanical properties; dimethylamino propylamine has fast curing characteristics and can provide high mechanical strength and heat resistance.

[0041] The invention adopts an in-situ polymerization method to prepare a water polyurethane emulsion, mixes it evenly with a curing agent, and uses polydopamine as an adhesive to coat it 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 a metal substrate has good hydrophobicity, chemical stability and anti-scaling and anti-corrosion performance.

[0042] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it 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 within the scope limited by the appended claims of the application equally.

[0043] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "%" means weight %, and ratio means weight ratio.

[0044] Example 1 The following raw materials were weighed respectively according to mass percentage: polypropylene glycol 45%, diphenylmethane diisocyanate 5%, nanoparticle modified amino silicone oil 0.6%, cyclohexylamine 1.4%, dimethylol propionic acid 2%, triethylamine 1%, water 45%; The weighed polypropylene glycol was added to diphenylmethane diisocyanate, and stirred at 45°C for 0.5 h to obtain an -NCO-terminated prepolymer; 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 mixed material; Add the weighed dimethylolpropionic acid to the mixture, and stir at 45° C. for 1 hour to obtain a hydrophilic chain-extended mixture; The weighed triethylamine was added to the hydrophilic chain extension mixture, and stirred at 30° C. for 0.5 h to obtain a neutralized mixture; The weighed water was added to the neutralized mixture, and stirred at 20° C. for 1 h to obtain a waterborne polyurethane emulsion; 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 a metal substrate anti-fouling and anti-corrosion super hydrophobic coating.

[0045] Example 2 The following raw materials were weighed respectively according to mass percentage: 55% polyether triol, 8% isophorone diisocyanate, 0.9% nanoparticle modified polydimethylsiloxane, 2.1% polyaniline, 3% dihydroxymethylbutyric acid, 2% triethanolamine, and 29% water; The weighed polyether triol was added to isophorone diisocyanate, and stirred at 55°C for 1 hour to obtain a -NCO-terminated prepolymer; 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 mixed material; 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; The weighed triethanolamine was added to the hydrophilic chain extension mixture, and stirred at 40° C. for 1 h to obtain a neutralized mixture; The weighed water was added to the neutralized mixture, and stirred at high speed for 1.5 hours at 30° C. to obtain a waterborne polyurethane emulsion; The obtained aqueous polyurethane emulsion and diaminocyclohexane were evenly mixed in a mass ratio of 10:1, and cured at 30° C. for 1 h to obtain an anti-fouling and anti-corrosion super hydrophobic coating for a metal substrate.

[0046] Example 3 The following raw materials were weighed respectively according to mass percentage: 65% propylene oxide copolymer glycol, 10% 1,6-hexamethylene diisocyanate, 1.2% nanoparticle modified octadecylamine, 2.8% diethylenetriamine, 4% 1,2-propylene glycol-3-sulfonate sodium, 3% N-methyldiethanolamine, and 14% water; The weighed propylene oxide copolymer glycol was added to 1,6-hexamethylene diisocyanate, and stirred at 65° C. for 1.5 h to obtain an -NCO-terminated prepolymer; 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 mixed material; The weighed 1,2-propylene glycol-3-sulfonate sodium was added to the mixture, and stirred at 65° C. for 2 h to obtain a hydrophilic chain extension mixture; Add the weighed N-methyldiethanolamine to the hydrophilic chain extension mixture, and stir at 50° C. for 1.5 h to obtain a neutralized mixture; The weighed water was added to the neutralized mixture, and stirred at high speed for 2 hours at 40° C. to obtain a waterborne polyurethane emulsion; The obtained aqueous polyurethane emulsion and isophorone diamine were evenly mixed in a mass ratio of 15:1, and cured at 40° C. for 1.5 h to obtain an anti-fouling and anti-corrosion super hydrophobic coating for a metal substrate.

[0047] Example 4 The following raw materials were weighed in percentage by mass: 55% polyethylene glycol, 12% toluene diisocyanate, 1.5% nanoparticle-modified polyoxypropylene diamine, 3.5% hexadecyltrimethylammonium bromide, 5% sodium 1,4-butanediol-2-sulfonate, 4% N,N-dimethylaminoethyl methacrylate, and 19% water; The weighed polyethylene glycol was added to toluene diisocyanate and stirred at 75°C for 2 hours to obtain a -NCO terminated prepolymer; The weighed nanoparticle-modified polyoxypropylene diamine and hexadecyl trimethyl ammonium bromide were added to the -NCO-terminated prepolymer, and stirred at 75° C. for 2 h to obtain a mixed material; 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 extension mixture; Add the weighed N,N-dimethylaminoethyl methacrylate to the hydrophilic chain extension mixture, and stir at 50° C. for 2 h to obtain a neutralized mixture; The weighed water was added to the neutralized mixture, and stirred at high speed for 2.5 hours at 60° C. to obtain a waterborne polyurethane emulsion; The obtained aqueous polyurethane emulsion and diethylaminopropylamine were evenly mixed in a mass ratio of 20:1, and cured at 50° C. for 2 h to obtain an anti-fouling and anti-corrosion super hydrophobic coating for a metal substrate.

[0048] Example 5 Weigh the following raw materials according to mass percentage: Polyether triol 55%, toluene diisocyanate 10%, nanoparticle modified polydimethylsiloxane 0.9%, polyaniline 2.1%, dimethylolbutyric acid 3%, N, N-dimethylaminobenzoic acid isooctyl ester 3%, water 26%; The weighed polyether triol was added to isophorone diisocyanate, and stirred at 85°C for 2.5 hours to obtain a -NCO-terminated prepolymer; 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 mixed material; The weighed dimethylolbutyric acid is added to the mixture, and stirred at 85° C. for 3 hours to obtain a hydrophilic chain-extended mixture; Add the weighed isooctyl N,N-dimethylaminobenzoate to the hydrophilic chain extension mixture, and stir at 70° C. for 2.5 hours to obtain a neutralized mixture; The weighed water was added to the neutralized mixture, and stirred at high speed at 60° C. for 3 h to obtain a waterborne polyurethane emulsion; 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 a metal substrate anti-fouling and anti-corrosion super hydrophobic coating.

[0049] Example 6 Weigh the following raw materials according to mass percentage: 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 dimethylol propionic acid and dimethylol butyric acid 6%, a mixture of triethylamine and triethanolamine 5%, and water 16%; 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; Add the weighed mixture of nanoparticle-modified amino silicone oil and nanoparticle-modified polydimethylsiloxane and the mixture of cyclohexylamine and polyaniline to the -NCO-terminated prepolymer, and stir at 85° C. for 2.5 h to obtain a mixed material; 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; 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; The weighed water was added to the neutralized mixture, and stirred at high speed at 60° C. for 3 h to obtain a waterborne polyurethane emulsion; 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.

[0050] Example 7 Weigh the following raw materials according to mass percentage: A mixture of polypropylene glycol, polyether triol, oxypropylene 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 amino silicone oil, nanoparticle-modified polydimethylsiloxane, nanoparticle-modified octadecylamine and nanoparticle-modified polyoxypropylene diamine 1.5%, a mixture of cyclohexylamine, polyaniline, diethylenetriamine and hexadecyltrimethylammonium bromide 3.5%, a mixture of dimethylolpropionic acid, dimethylolbutyric acid, 1,2-propylene glycol-3-sulfonate sodium and 1,4-butanediol-2-sulfonate sodium 6%, a mixture of triethylamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylaminoethyl methacrylate and isooctyl p-N,N-dimethylaminobenzoate 5%, and water 4%; Add the weighed mixture of polypropylene glycol, polyether triol, propylene oxide copolymer glycol and polyethylene glycol to the mixture of diphenylmethane diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate and toluene diisocyanate, and stir at 85° C. for 2.5 h to obtain an -NCO terminated prepolymer; Add 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 to the -NCO-terminated prepolymer, and stir at 85° C. for 2.5 h to obtain a mixed material; Add the weighed mixture of dimethylolpropionic acid, dimethylolbutyric acid, 1,2-propylene glycol-3-sodium sulfonate and 1,4-butanediol-2-sodium sulfonate to the mixed material, and stir at 85° C. for 3 hours to obtain a hydrophilic chain extension mixed material; Add the weighed mixture of triethylamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylaminoethyl methacrylate and isooctyl p-N,N-dimethylaminobenzoate to the hydrophilic chain extension mixture, and stir at 70° C. for 2.5 hours to obtain a neutralized mixture; The weighed water was added to the neutralized mixture, and stirred at high speed at 60° C. for 3 h to obtain a waterborne polyurethane emulsion; 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.

[0051] like Figure 1As shown, the contact angle of the metal substrate not coated with the aqueous polyurethane emulsion is 85°, and 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 hydrophobic effect of the metal substrate coated with the anti-fouling and anti-corrosion super-hydrophobic coating of the present invention is better.

[0052] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a super hydrophobic coating for metal substrate anti-fouling and anti-corrosion, 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 stirred to react 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 stirred to react to obtain a mixed material; 2% to 6% of a hydrophilic chain extender is added to the mixed material, and stirred to react to obtain a hydrophilic chain extension mixed material; 1% to 5% of a neutralizer is added to the hydrophilic chain extension mixed material, and stirred to react to obtain a neutralized mixed material; 4% to 45% of water is added to the neutralized mixed material, and stirred to react to obtain an aqueous polyurethane emulsion; after the aqueous polyurethane emulsion and a curing agent are evenly mixed, they are 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 waterborne polyurethane emulsion to the curing agent is (5-20):

1.

2. A method for preparing a super hydrophobic coating for metal substrate anti-fouling and anti-corrosion 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 super hydrophobic coating for metal substrate anti-scaling and anti-corrosion 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 nanoparticle hydrophobic modifier is one or more of nanoparticle-modified aminosilicone oil, nanoparticle-modified polydimethylsiloxane, nanoparticle-modified octadecylamine and nanoparticle-modified polyoxypropylenediamine.

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 preparation method of the nanoparticle hydrophobic modifier is as follows: 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 a water-in-oil system, and the reaction is carried out at 50-90° C. for 2-5 hours to obtain the nanoparticle modified hydrophobic agent.

6. 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.

7. 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.

8. A method for preparing a super hydrophobic coating for metal substrate anti-scaling and anti-corrosion 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.

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

10. A super hydrophobic coating for anti-scaling and anti-corrosion of metal substrates, characterized in that: The method is prepared by the method according to any one of claims 1 to 9.

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