A marine-grade anti-aging, low-adhesion composite coating, its preparation method and application

Abstract

The invention discloses an anti-aging low-adhesion composite coating suitable for marine equipment, a preparation method and an application thereof, and belongs to the technical field of surface coatings for coastal equipment. After spraying polyaspartic acid polyurea on the surface of a substrate, a layer of modified perfluoropolyether grease is applied thereon, wherein the modified perfluoropolyether grease is obtained by adding nano hexagonal boron nitride to the perfluoropolyether grease for modification; the adhesion of the polyurea coating to the substrate is improved by modifying the isocyanate, thereby improving the impact resistance of the coating; the impact resistance of the polyurea coating is improved by adding modified carbon nanofibers and modified graphene oxide, and the coating is also resistant to marine corrosion; the coating is made highly weather-resistant by adding ultraviolet light absorbers and light stabilizers, the corrosion resistance of the coating is improved by adding polyaspartic acid resin containing carboxymethyl cellulose, and the anti-icing performance of the coating is increased by spraying nano hexagonal boron nitride-modified perfluoropolyether grease.

Description

Technical Field

[0001] The present invention relates to the field of marine coatings, and in particular to an anti-aging low-adhesion composite coating suitable for marine coatings, a preparation method and an application thereof. Background Art

[0002] The total output value of my country's marine industry accounts for about 9% of the country's total output value, and the marine industry is booming. However, in the process of marine infrastructure and construction, ultraviolet rays and sea breezes will bring serious safety hazards and cause major property losses. According to statistics, the corrosion of my country's marine industry accounts for about 1 / 3 of all corrosion in my country, and in cold environments, ice on the surface of marine equipment will also cause energy loss and cause safety hazards. Therefore, it is particularly important to develop a low-cost, marine pollution-resistant, UV-resistant, and anti-icing protection technology. The current anti-marine corrosion technology is mainly divided into the following categories: 1. Electrochemical protection, using the metal-electrolyte dissolution corrosion system to be subjected to cathode polarization, the potential shifts negatively, the metal anode oxidation reaction overpotential decreases, the reaction rate decreases, and the metal corrosion rate decreases. However, a non-conductive shell is easily generated on the outside of the anode, affecting the anti-corrosion effect. 2. Use anti-corrosion materials and corrosion-resistant metal materials to slow down the reaction rate of electrochemical corrosion. However, this method can only slow down the corrosion rate and will still cause serious losses over a long period of time. 3. Use coating protection methods. Compared with the above two methods, the coating protection method has low cost, environmental protection, energy saving, and high performance. Compared with manual de-icing, the cost of autonomous de-icing is greatly reduced and safety is also improved accordingly.

[0003] Polyurea is an elastomeric spray material formed by the reaction of isocyanate components and amino compounds. It has the advantages of low cost, environmental protection, energy saving, etc., and has good impact strength, corrosion resistance, waterproofness, and high flexibility. However, the existing polyurea coating has poor UV aging resistance and a high friction coefficient on its surface. It cannot promote the shedding of marine pollution from its surface, cannot promote the rolling of droplets, cannot delay the crystallization process, and cannot reduce the adhesion of ice to the substrate after crystallization. Therefore, it does not have the function of anti-icing. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an anti-aging and low-adhesion composite coating suitable for marine equipment, which has high adhesion performance to marine equipment and is an ultra-slip polyurea composite coating that can resist UV aging and prevent icing. The coating can not only increase the service life of the coating, but also reduce the adhesion of ice to the substrate after crystallization and the corrosion of marine pollution, thereby improving the working efficiency and service life of marine equipment.

[0005] The present invention achieves the above technical objectives through the following technical means.

[0006] An anti-aging low-adhesion composite coating suitable for marine equipment, comprising: spraying polyaspartic acid polyurea on the surface of a substrate and then coating it with a layer of modified perfluoropolyether grease, wherein the modified perfluoropolyether grease is obtained by adding nano hexagonal boron nitride to the perfluoropolyether grease;

[0007] The polyaspartic acid polyurea is composed of component A and component B; the mass ratio of component A to component B is 1:1.2-1.5;

[0008] The raw materials for preparing the component A include 35 to 50 parts of modified isocyanate, 15 to 30 parts of modified graphene oxide and 1 to 10 parts of diluent in parts by weight;

[0009] By weight, the raw materials for preparing the component B include 30-50 parts of polyaspartic acid resin, 2-5 parts of dispersant, 1-3 parts of ultraviolet light absorber, 2-5 parts of light stabilizer, 1-10 parts of diluent, 3-10 parts of modified nano titanium dioxide and 10-20 parts of auxiliary agent.

[0010] In the above scheme, the modified isocyanate is prepared by mixing isocyanate and biuret at a mass fraction of 1:1 and then adding modified carbon nanofibers. In the above scheme, the preparation method of the modified carbon nanofibers is: modifying carbon nanofibers CNF-OH with hydroxyl groups on the surface with methyltrimethoxysilane to obtain modified carbon nanofibers.

[0011] In the above scheme, the preparation method of the modified graphene oxide is: modifying graphene oxide with an L-tryptophan solution to obtain modified graphene oxide.

[0012] In the above scheme, the polyaspartic acid resin is obtained by mixing polyaspartic acid ester, modified polysuccinimide and carboxymethyl cellulose in a ratio of 8:1:1 and then modifying them in a NaOH solution.

[0013] In the above scheme, the modified polysuccinimide is obtained by modifying polysuccinimide in N,N'-dimethylformamide (DMF) solution.

[0014] In the above scheme, the modified nano titanium dioxide is obtained by mixing liquid titanium dioxide and sodium aluminate aqueous solution to obtain the modified nano titanium dioxide.

[0015] In the above scheme, the diluents in component A and component B independently include propylene carbonate or n-butyl acetate; the auxiliary agent includes 7 to 10 parts of ethyl acetate, 2 to 3 parts of leveling agent, 1 to 2 parts of defoaming agent and 2 to 5 parts of silane coupling agent by weight.

[0016] The preparation method of the anti-aging low-adhesion composite coating suitable for marine equipment comprises the following steps: mixing component A and component B at 60-80°C, spraying the components, and spraying modified perfluoropolyether lubricating ester on the surface after curing to obtain the anti-aging low-adhesion composite coating suitable for marine equipment.

[0017] Application of anti-aging and low-adhesion composite coating suitable for marine equipment, and application of the prepared anti-aging and low-adhesion composite coating suitable for marine equipment on the surface of marine equipment.

[0018] Beneficial effects:

[0019] The invention improves the adhesion of the polyurea coating to the substrate by using modified isocyanate, thereby improving the impact resistance of the coating, and improving the construction performance and service life of the coating; by adding modified graphene oxide, the coating has marine corrosion resistance; by adding modified nano titanium dioxide, the anti-aging performance of the coating is improved; by adding ultraviolet light absorbers and light stabilizers, the coating has high weather resistance, by adding polyaspartic acid resin containing carboxymethyl cellulose, the corrosion resistance of the coating is improved, by modifying perfluoropolyether grease, the friction coefficient of the surface of the polyurea coating is greatly reduced, and the adhesion of ice to the polyurea coating after crystallization is further reduced, so as to achieve the functionality of anti-icing. DETAILED DESCRIPTION

[0020] The present invention provides an anti-aging low-adhesion composite coating suitable for marine equipment, which is formed by spraying polyaspartic acid polyurea on the surface of a base member and then spraying modified perfluoropolyether grease; the polyaspartic acid polyurea is solidified by component A and component B; the mass ratio of component A to component B is 1:1.2-1.5;

[0021] In terms of weight, the raw materials for preparing component A include 35-50 parts of modified isocyanate, 15-30 parts of modified graphene oxide and 1-10 parts of diluent;

[0022] The modified isocyanate is prepared by mixing isocyanate and biuret at a mass fraction of 1:1 and then adding modified carbon nanofibers to mix; the preparation method of the modified carbon nanofibers is: modifying carbon nanofibers CNF-OH with hydroxyl groups on the surface with methyltrimethoxysilane to obtain modified carbon nanofibers;

[0023] The modified graphene oxide is an L-tryptophan modified graphene oxide dispersion prepared by adding graphene oxide to a NaOH solution;

[0024] The raw materials for component B include 30-50 parts of polyaspartic acid resin, 2-5 parts of dispersant, 1-3 parts of defoamer, 1-3 parts of ultraviolet light absorber, 2-5 parts of light stabilizer, 3-7 parts of diluent, 3-10 parts of modified nano titanium dioxide and 10-20 parts of auxiliary agent in parts by weight.

[0025] The preparation method of the polyaspartic acid resin is as follows: polyaspartic acid ester, modified polysuccinimide and carboxymethyl cellulose are mixed in a ratio of 8:1:1 and then modified in a NaOH solution.

[0026] The preparation method of the modified polysuccinimide is as follows: polysuccinimide is modified in an N,N'-dimethylformamide (DMF) solution to obtain the modified polysuccinimide.

[0027] The preparation method of modified nano titanium dioxide is to mix silicon dioxide dissolved in water with a sodium aluminate aqueous solution to obtain modified nano titanium dioxide.

[0028] In the present invention, the polyaspartic acid polyurea coating is formed by curing component A and component B; the mass ratio of component A to component B is 1:1.2 to 1.5, preferably 1:1.4 to 1.5. The present invention controls the mass ratio of component A to component B within the above range, which is conducive to the curing of component A and component B, thereby obtaining a multifunctional polyurea coating.

[0029] The raw materials for preparing the component A include 30 to 55 parts of modified isocyanate, preferably 38 to 50 parts, and more preferably 47 to 50 parts by weight. In the present invention, the modified isocyanate is prepared by mixing isocyanate and biuret at a mass fraction of 1:1 and then adding modified carbon nanofibers. The adhesion of the coating is improved through the chemical bonding between the hydroxyl group and the surface of the substrate, which is beneficial to improving the impact resistance of the coating.

[0030] In the present invention, the isocyanate in the modified isocyanate preferably includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl polyisocyanate and isophorone diisocyanate, more preferably one or more of diphenylmethane diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate. The present invention has no particular limitation on the source of the isocyanate, and commercial products well known to those skilled in the art can be used.

[0031] In the present invention, the preparation method of the modified isocyanate preferably comprises: under a nitrogen atmosphere, compounding isocyanate and biuret in a mass fraction of 1:1, and then adding modified carbon nanofibers to mix to obtain modified isocyanate. In the present invention, the mass ratio of isocyanate to biuret is preferably 1:(0.8-1), more preferably 1:1. In the present invention, the mixing is preferably stirred after ultrasonic treatment. In the present invention, the power of the ultrasonic treatment is preferably 20-40kHz, more preferably 30-40kHz; the time of the ultrasonic treatment is preferably 40-60min, more preferably 50-60min. In the present invention, the stirring rate is preferably 1500-2500r / min, more preferably 2000-2500r / min; the stirring time is preferably 4-6h, more preferably 6h.

[0032] In the present invention, the preparation method of the carbon nanofiber CNF-OH with hydroxyl groups on the surface preferably comprises: mixing the carbon nanofiber with concentrated nitric acid, and then sequentially performing a first ultrasonic treatment and a first heating reflux to obtain an acidified carbon nanofiber CNF-COOH; mixing the acidified carbon nanofiber CNF-COOH with thionyl chloride, and then sequentially performing a second ultrasonic treatment and a second heating reflux to obtain an acylated carbon nanofiber CNF-COCl; mixing the acylated carbon nanofiber CNF-COCl with ethylene glycol, and then sequentially performing a third ultrasonic treatment and a hydroxylation reaction to obtain a carbon nanofiber CNF-OH with hydroxyl groups on the surface. In the present invention, the carbon nanofiber is preferably mixed with concentrated nitric acid, and then sequentially performing a first ultrasonic treatment and a first heating reflux to obtain an acidified carbon nanofiber CNF-COOH. In the present invention, the diameter of the carbon nanofiber is preferably 120 to 130 nm; the length of the carbon nanofiber is preferably 10 to 20 μm. In the present invention, the volume ratio of the mass of the carbon nanofiber to the concentrated nitric acid is preferably (5 to 6) g: (80 to 100) mL. In the present invention, the mass concentration of the concentrated nitric acid is preferably 75-78%.

[0033] In the present invention, the frequency of the first ultrasonic treatment is preferably 25 to 30 kHz; the time of the first ultrasonic treatment is preferably 10 to 20 min.

[0034] In the present invention, the temperature of the first heating reflux is preferably 120-130° C.; the time of the first heating reflux is preferably 2-3 hours.

[0035] After the first heating and reflux is completed, the present invention preferably dilutes, filters, washes and dries the product of the first heating and reflux in sequence to obtain acidified carbon nanofibers CNF-COOH. The present invention has no special restrictions on the operations of dilution, filtration, washing and drying, and the technical schemes of dilution, filtration, washing and drying well known to those skilled in the art can be used. In the present invention, the diluent used for the dilution is preferably deionized water; the amount of deionized water is preferably 1000mL. In the present invention, the filter membrane used for the filtration is preferably a Φ0.22μm mixed fiber microporous filter membrane. In the present invention, the detergent used for washing is preferably deionized water. In the present invention, the drying temperature is preferably 80-90°C; the drying time is preferably 24-25h; the drying method is preferably vacuum drying. After obtaining the acidified carbon nanofibers CNF-COOH, the present invention preferably mixes the acidified carbon nanofibers CNF-COOH with thionyl chloride, and then sequentially performs a second ultrasonic treatment and a second heating and reflux to obtain acylated carbon nanofibers CNF-COCl.

[0036] In the present invention, the mass ratio of the acylated carbon nanofiber CNF-COOH to the volume ratio of thionyl chloride is preferably (2-3) g: (80-90) mL. In the present invention, the frequency of the second ultrasonic treatment is preferably 25-30 kHz; the time of the second ultrasonic treatment is preferably 10-20 min. In the present invention, the temperature of the second heating reflux is preferably 75-85°C; the time of the second heating reflux is preferably 24-25 h. After the second heating reflux is completed, the present invention preferably performs vacuum distillation on the product of the second heating reflux to obtain the acylated carbon nanofiber CNF-COCl. The present invention removes excess thionyl chloride by vacuum distillation, which is beneficial to obtain pure acylated carbon nanofiber CNF-COCl. The present invention has no special limitation on the operation of the vacuum distillation, and the technical scheme of vacuum distillation well known to those skilled in the art can be adopted.

[0037] After obtaining the acylated carbon nanofiber CNF-COCl, the present invention preferably mixes the acylated carbon nanofiber CNF-COCl with ethylene glycol, and then sequentially performs a third ultrasonic treatment and a hydroxylation reaction to obtain a carbon nanofiber CNF-OH with hydroxyl groups on the surface. In the present invention, the mass ratio of the acylated carbon nanofiber CNF-COCl to the volume ratio of ethylene glycol is preferably (1.5-2) g: (80-90) mL. In the present invention, the frequency of the third ultrasonic treatment is preferably 25-30 kHz; the time of the third ultrasonic treatment is preferably 10-20 min. In the present invention, the temperature of the hydroxylation reaction is preferably 120-130°C; the time of the hydroxylation reaction is preferably 48-50 h.

[0038] After the hydroxylation reaction is completed, the present invention preferably dilutes, filters, washes and dries the product of the hydroxylation reaction in sequence to obtain carbon nanofiber CNF-OH with hydroxyl groups on the surface. The present invention has no special restrictions on the operations of dilution, filtration, washing and drying, and the technical schemes of dilution, filtration, washing and drying well known to those skilled in the art can be adopted. In the present invention, the diluent used for the dilution is preferably deionized water; the amount of deionized water is preferably 1000mL. In the present invention, the filter membrane used for the filtration is preferably a Φ0.22μm mixed fiber microporous filter membrane. In the present invention, the detergent used for washing is preferably deionized water. In the present invention, the drying temperature is preferably 80-90°C; the drying time is preferably 24-25h; the drying method is preferably vacuum drying.

[0039] Based on 30 to 55 parts by weight of modified isocyanate, the raw materials for preparing component A include 15 to 30 parts, preferably 17 to 30 parts, and more preferably 22 to 30 parts of modified graphene oxide. In the present invention, the modified graphene oxide comes from L-tryptophan modified graphene oxide dispersion.

[0040] The method for preparing the L-tryptophan modified graphene oxide dispersion of the present invention comprises preparing the following raw materials according to weight percentage:

[0041] Graphene oxide slurry (containing 40% water): 1-10%, L-tryptophan: 0.5-6%, deionized water: 80-95%, sodium hydroxide: 0.1-2%; and the sum of the weight percentage contents of the above components is 100%;

[0042] Preparation of L-tryptophan solution: firstly, L-tryptophan and deionized water are mixed to prepare a solution, then granular sodium hydroxide is added, and a magnetic stirrer is started to disperse the solution for 0.5 to 2 hours to obtain a light yellow transparent L-tryptophan solution;

[0043] Preparation of graphene oxide aqueous dispersion: dissolving the graphene oxide slurry in the L-tryptophan solution obtained in step (1.2), stirring with a magnetic force for 0.5 to 2 hours, and then ultrasonically bathing for 0.5 to 2 hours to preliminarily obtain a uniformly dispersed dark brown graphene oxide aqueous dispersion;

[0044] Preparation of L-tryptophan modified graphene oxide dispersion: The graphene oxide aqueous dispersion obtained in step (1.3) is stirred magnetically and reacted at room temperature for 24 hours. During this period, the graphene oxide slurry can be quickly dissolved in the L-tryptophan solution due to its high water content, and undergoes a grafting reaction with L-tryptophan, resulting in a slight reduction of the graphene oxide, and the dispersion changes from dark brown to dark brown, presenting a uniform sol state, thereby obtaining an L-tryptophan modified graphene oxide dispersion;

[0045] Based on 30 to 55 parts by weight of the modified isocyanate, the raw materials for preparing the component A include 3 to 10 parts of diluent, preferably 5 to 10 parts, and more preferably 8 to 10 parts. In the present invention, the diluent is used to adjust the NCO value and viscosity of component A. In the present invention, the diluent preferably includes propylene carbonate or n-butyl acetate, more preferably propylene carbonate. The present invention has no special limitation on the source of the diluent, and commercial products well known to those skilled in the art can be used.

[0046] In the present invention, the preparation method of component A preferably comprises: reacting isocyanate, biuret and modified carbon nanofiber at 60-90° C. for 3-4 hours, then sequentially adding modified graphene oxide and diluent, stirring for 4-5 hours, to obtain component A.

[0047] The present invention preferably reacts carbon nanofibers with hydroxyl groups on the surface, isocyanate and biuret in a nitrogen atmosphere at 60-90°C for 3-4h to obtain a polymer. The present invention uses isocyanate and biuret as raw materials for polymerization reaction to prepare a polymer. In the present invention, the reaction temperature is preferably 60-70°C; the reaction time is preferably 3h. After obtaining the polymer, the present invention preferably adds modified graphene oxide and diluent in sequence, and stirs for 4-5h to obtain component A. The present invention improves the marine corrosion resistance and aging resistance of the polymer by adding modified graphene oxide to the polymer, and adjusts the NCO value and viscosity of the polymer by adding a diluent. In the present invention, the NCO value of component A is preferably 12-15%; the viscosity of component A is preferably 700-800mPa·s. In the present invention, the stirring rate is preferably 1500-2000r / min; the stirring time is preferably 4h.

[0048] Based on 30 to 55 parts by weight of the modified isocyanate, the raw materials for preparing the component B include 30 to 50 parts of polyaspartic acid resin, more preferably 33 to 45 parts, and more preferably 35 to 45 parts. In the present invention, the polyaspartic acid resin is a modified polyaspartic acid / polyacrylic acid / carboxymethyl cellulose ternary composite highly absorbent resin.

[0049] In the present invention, the preparation method of the modified polyaspartic acid / polyacrylic acid / carboxymethyl cellulose ternary composite super absorbent resin is preferably as follows: 1g of polysuccinimide is placed in a beaker containing 10mL of N,N'-dimethylformamide, fully dissolved in a 35°C water bath for 2h, then 40μL of KH-550 silane coupling agent is added, the temperature is raised to 50°C, and the reaction is carried out under constant temperature stirring (speed 100r / min) for 3h, and after the reaction, 10mL of anhydrous ethanol is used for precipitation, and the powdered modified polysuccinimide is repeatedly washed 3 times. 1g of the modified polysuccinimide is dispersed in a beaker containing 10mL of deionized water, and a 2mol / L NaOH solution is added dropwise in a 35°C water bath, and the pH of the solution is maintained at 9-10 and no longer changes. Then, a certain amount of carboxymethyl cellulose was weighed and placed in the reaction solution, stirred (speed 100 r / min) for gelatinization for 30 min, 0.5% (based on acrylic acid) of KPS, a certain amount of acrylic acid with a neutralization degree of 70%, and 0.1% (based on acrylic acid) of N,N'-methylenebisacrylamide were added in sequence, nitrogen was passed, and stirring (speed 100 r / min) was stopped for 10 min. The mixture was allowed to stand at 70°C for 3 h to react. The product was placed in an oven and dried at 70°C for 24 h, and then crushed to obtain a solid powder modified polyaspartic acid / polyacrylic acid / carboxymethyl cellulose ternary composite highly absorbent resin.

[0050] Based on 30 to 55 parts by weight of the modified isocyanate, the raw materials for preparing the component B include 1 to 10 parts of ultraviolet light absorbers, preferably 5 to 10 parts, and more preferably 8 to 10 parts. The present invention improves the weather resistance of the coating by adding ultraviolet light absorbers, thereby improving the corrosion resistance of the coating to marine corrosive environments.

[0051] In the present invention, the ultraviolet light absorber preferably includes one or more of o-hydroxybenzoic acid phenyl ester, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2,4-dihydroxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, and monobenzoic acid resorcinol ester, and more preferably one or more of o-hydroxybenzoic acid phenyl ester and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole. The present invention has no particular limitation on the source of the ultraviolet light absorber, and commercially available products known to those skilled in the art can be used.

[0052] Based on 30 to 55 parts by weight of the modified isocyanate, the raw materials for preparing the component B include 1 to 10 parts of light stabilizer, preferably 5 to 10 parts, and more preferably 8 to 10 parts. The present invention adds a light stabilizer and uses a UV light absorber and a light hindered amine stabilizer in combination, so that the polyurea coating has excellent weather resistance. In the present invention, the source of the light stabilizer is not particularly limited, and commercial products well known to those skilled in the art can be used.

[0053] Based on 10 to 28 parts by weight of the chain extender, the raw materials for preparing the component B include 12 to 20 parts of auxiliary agents. In the present invention, based on weight, the auxiliary agents preferably include 7 to 10 parts of ethyl acetate, 2 to 3 parts of leveling agents, 1 to 2 parts of defoaming agents, and 2 to 5 parts of silane coupling agents. In the present invention, the leveling agent is preferably AKN-3600; the defoaming agent is preferably DU-964; and the silane coupling agent is preferably KH550.

[0054] In parts by weight, the raw materials for preparing the component B include 10 to 28 parts of chain extenders, preferably 20 to 28 parts, and more preferably 25 to 28 parts. In the present invention, the chain extender preferably includes one or more of diethyltoluenediamine, dimethylthiotoluenediamine, and N,N'-dialkylmethyldiamine, more preferably diethyltoluenediamine and N,N'-dialkylmethyldiamine. The present invention has no particular limitation on the source of the chain extender, and commercial products well known to those skilled in the art can be used.

[0055] Based on 10 to 28 parts by weight of the chain extender, the raw materials for preparing the component B include 5 to 15 parts of a diluent, preferably 7 to 10 parts, and more preferably 9 to 10 parts. In the present invention, the diluent preferably includes propylene carbonate or n-butyl acetate, more preferably n-butyl acetate. The present invention has no particular limitation on the source of the diluent, and commercial products well known to those skilled in the art can be used.

[0056] The raw materials for preparing the component B include 3 to 10 parts of nano titanium dioxide, based on the weight of the chain extender being 10 to 28 parts, and the preparation method of modified nano titanium dioxide with hydrophobicity and anti-ultraviolet aging properties. (1) 1000 g of a nano titanium dioxide aqueous dispersion with a mass percentage of 10% is measured and placed in a 3000 mL three-necked flask, the stirring device is started, the temperature of the nano titanium dioxide aqueous dispersion is adjusted to 40° C., and a sodium aluminate aqueous solution with a mass percentage of 4% and a phosphoric acid aqueous solution with a mass percentage of 5% are added to the nano titanium dioxide aqueous dispersion, and the pH value of the system is maintained at 8.0. The amount of sodium aluminate used is based on the mass of AlPO4 generated, accounting for 4% of the mass of the nano titanium dioxide. After the sodium aluminate aqueous solution is added, continue stirring and aging at 40° C. for 10 minutes. Raise the temperature of the nano titanium dioxide aqueous dispersion to 95°C, add a 10% sodium silicate aqueous solution and a 5% nitric acid aqueous solution to the nano titanium dioxide aqueous dispersion, and maintain the pH value of the system at 10.5. The amount of sodium silicate is calculated based on the mass of SiO2 generated, accounting for 8% of the mass of nano titanium dioxide. After the sodium silicate aqueous solution is added, continue to stir and mature at 95°C for 60 minutes. Adjust the temperature of the nano titanium dioxide aqueous dispersion to 50°C, add a 4% sodium aluminate aqueous solution and a 5% nitric acid aqueous solution to the nano titanium dioxide, and maintain the pH value of the system at 8.0. The amount of sodium aluminate is calculated based on the mass of Al2O3 generated, accounting for 10% of the mass of nano titanium dioxide. After the sodium aluminate aqueous solution is added, continue to stir and mature at 50°C for 30 minutes. The pH value of the system was adjusted to 5.0 with a 5% nitric acid aqueous solution, and the temperature of the nano titanium dioxide aqueous dispersion was adjusted to 85°C. An aqueous solution containing 20g of sodium stearate was added to the nano titanium dioxide aqueous dispersion, and the mixture was stirred and matured for 300 minutes. The nano titanium dioxide slurry was filtered and washed with deionized water until the conductivity of the filtrate was less than 500μS / cm. After drying and crushing, a hydrophobic nano titanium dioxide powder was obtained.

[0057] Based on 10 to 28 parts by weight of the chain extender, the raw material for preparing the component B includes 1 to 10 parts of a foaming agent, preferably 1 to 5 parts, and more preferably 1 to 3 parts. The present invention can reduce the use of polyurea coatings by adding a foaming agent, while achieving the purpose of reducing sea load, saving costs and protecting the environment, and does not affect the impact resistance of the polyurea coating.

[0058] In the present invention, the foaming agent preferably includes azobisisobutyronitrile or N,N'-dimethyl-N,N'-dinitrosoterephthalamide, more preferably azobisisobutyronitrile. The present invention has no particular limitation on the source of the foaming agent, and commercial products known to those skilled in the art can be used.

[0059] In the present invention, the preparation method of component B preferably comprises: mixing raw materials except the auxiliary agent, then heating at 90-102° C. for 3-4 hours, adding the auxiliary agent, and stirring for 20-30 minutes to obtain component B.

[0060] In the present invention, the raw materials other than the auxiliary agent are preferably mixed to obtain a mixture. In the present invention, the mixing of the raw materials other than the auxiliary agent is preferably carried out under stirring. In the present invention, the stirring rate is preferably 1500 to 2000 r / min; the stirring time is preferably 30 to 50 min.

[0061] After obtaining the mixture, the present invention preferably heats the mixture at 90-102° C. for 3-4 hours to obtain the amino polymer. In the present invention, the heating temperature is preferably 90° C.; the heating time is preferably 3 hours.

[0062] After obtaining the amino polymer, the present invention preferably adds an auxiliary agent to the amino polymer and stirs for 20 to 30 minutes to obtain component B. In the present invention, the stirring rate is preferably 2000 to 2500 r / min; and the stirring time is preferably 20 minutes.

[0063] The preparation method of the modified perfluoropolyether grease of the present invention is to use the perfluoropolyether grease as a base oil, and the components thereof are 95-98 wt % of base oil and 2-5 wt % of nano hexagonal boron nitride, and the two are mixed and stirred at 40-60° C. for 30-40 minutes. In the present invention, the stirring rate is preferably 1500-2000 r / min; and the stirring time is preferably 35 minutes.

[0064] After components A and B are combined and cured, modified perfluoropolyether grease is sprayed on the surface.

[0065] The invention improves the adhesion of the polyaspartic acid polyurea coating to the substrate by adding modified isocyanate, thereby improving the construction performance of the coating; further improves the corrosion resistance of the coating by modifying graphene oxide; improves the marine corrosion resistance of the coating and increases the service life by adding a ternary composite polyaspartic acid resin; and improves the marine pollution resistance and anti-icing property of the coating by spraying nano hexagonal boron nitride-modified perfluoropolyether grease on the surface of the polyaspartic acid polyurea coating.

[0066] The present invention also provides a method for preparing the anti-aging and low-adhesion composite coating suitable for marine equipment as described in the above technical scheme, comprising: mixing component A and component B at 60-80°C, and then spraying them, and after components A and B are combined and cured, spraying modified perfluoropolyether grease on the surface to obtain the anti-aging and low-adhesion composite coating suitable for marine equipment.

[0067] The present invention allows component A and component B to react at 60-80° C. to generate a polyurea coating, which is then sprayed to obtain a multifunctional polyurea coating. In the present invention, the spraying equipment is preferably a high-pressure sprayer.

[0068] The present invention sprays component A and component B after mixing, and sprays modified perfluoropolyether grease after curing to obtain a marine-suitable anti-aging low-adhesion composite coating. The preparation method of the marine-suitable anti-aging low-adhesion composite coating provided by the present invention is simple to operate and ensures the performance of the coating.

[0069] The present invention also provides the use of the marine equipment-applicable anti-aging low-adhesion composite coating described in the above technical solution or the multifunctional coating for marine equipment prepared by the preparation method in marine equipment. In the present invention, the multifunctional polyurea coating is applied to the surface of the marine equipment to protect the marine equipment.

[0070] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0071] In the present invention:

[0072] The polyaspartic acid polyurea is composed of component A and component B; the mass ratio of component A to component B is 1:1.2-1.5;

[0073] The raw materials for preparing the component A include 35 to 50 parts of modified isocyanate, 15 to 30 parts of modified graphene oxide and 1 to 10 parts of diluent in parts by weight;

[0074] The raw materials for preparing the component B include, by weight, 30 to 50 parts of polyaspartic acid resin, 2 to 5 parts of dispersant, 1 to 3 parts of ultraviolet light absorber, 2 to 5 parts of light stabilizer, 1 to 10 parts of diluent, 3 to 10 parts of modified nano titanium dioxide and 10 to 20 parts of auxiliary agent;

[0075] The modified isocyanate is prepared by mixing isocyanate and biuret at a mass fraction of 1:1 and then adding modified carbon nanofibers; the preparation method of the modified carbon nanofibers is: using methyltrimethoxysilane to modify carbon nanofibers CNF-OH with hydroxyl groups on the surface to obtain modified carbon nanofibers.

[0076] Example 1

[0077] The mass ratio of component A to component B is: 1:1.2;

[0078] Component A raw materials (parts by weight):

[0079] 50 parts of modified diphenylmethane diisocyanate, 30 parts of modified graphene oxide and 8 parts of propylene carbonate DBGA.

[0080] Preparation of carbon nanofiber CNF-OH with hydroxyl groups on the surface: 5 g of carbon nanofiber (diameter 120 nm, length 10 μm) and 80 mL of 75 wt% concentrated nitric acid were placed in a 300 mL single-necked round-bottom beaker equipped with a magnetic rotor, ultrasonically treated at 25 kHz for 10 min, equipped with a spherical condenser and a tail gas absorption tube, heated to 120 ° C, stirred and refluxed for 2 h, and after the reaction was completed, diluted with 1000 mL of deionized water, filtered with a Φ0.22 μm mixed fiber microporous filter membrane, repeatedly washed with deionized water several times until neutral, and vacuum dried at 80 ° C for 24 h to obtain acidified carbon nanofiber CNF-COOH;

[0081] 2 g of acidified carbon nanofiber CNF-COOH and 80 mL of thionyl chloride were placed in a 300 mL single-necked round-bottom beaker equipped with a magnetic rotor, and ultrasonically treated at 25 kHz for 10 min, then heated to 75 °C, stirred and reacted under reflux for 24 h, and the excess thionyl chloride was removed by reduced pressure distillation to obtain acylated carbon nanofiber CNF-COCl;

[0082] 1.5 g of acylated carbon nanofiber CNF-COCl and 80 mL of ethylene glycol were placed in a 300 mL single-necked round-bottom beaker equipped with a magnetic rotor, and ultrasonically treated at 25 kHz for 10 min, and then reacted at 120 ° C for 48 h. After the reaction, it was diluted with 1000 mL of deionized water, and the excess ethylene glycol and by-products were removed by suction filtering with a Φ0.22 μm mixed fiber microporous filter membrane. After repeated washing with deionized water, it was vacuum dried at 80 ° C to obtain carbon nanofiber CNF-OH with hydroxyl groups on the surface;

[0083] Preparation of modified carbon nanofibers: 3 g of carbon nanofibers CNF-OH with hydroxyl groups on the surface, 1 mL of methyltrimethoxysilane MTMS and 3 mL of H2O were placed in a sealed reaction dish, reacted at 25°C for 10 min, and then placed in a -20°C dryer for 8 h to obtain modified carbon nanofibers;

[0084] The modified isocyanate is prepared by mixing isocyanate and biuret at a mass fraction of 1:1 and then adding modified carbon nanofibers; the preparation method of the modified carbon nanofibers is: using methyltrimethoxysilane to modify carbon nanofibers CNF-OH with hydroxyl groups on the surface to obtain modified carbon nanofibers.

[0085] Preparation of modified diphenylmethane diisocyanate: In a three-necked flask protected by nitrogen, 100 g of diphenylmethane diisocyanate and 100 g of biuret were mixed, and then 1 g of carbon nanofiber CNF-OH with hydroxyl groups on the surface was added thereto, and then ultrasonically treated at 25 kHz for 20 min, and then stirred at a rate of 2000 r / min for 5 h to obtain modified diphenylmethane diisocyanate;

[0086] Preparation of modified graphene oxide: graphene oxide slurry (containing 40% water): 1-10%, L-tryptophan: 0.5-6%, deionized water: 80-95%, sodium hydroxide: 0.1-2%; and the sum of the weight percentage content of the above components is 100%; first, L-tryptophan and deionized water are mixed to obtain a solution, and then granular sodium hydroxide is added, a magnetic stirrer is started for dispersion, and the mixture is stirred at a rate of 2500r / min for 0.5-2h to obtain a light yellow transparent L-tryptophan solution; the graphene oxide slurry is dissolved in the L-tryptophan solution, stirred at a rate of 3000r / min for 0.5-2h, and then ultrasonically bathed for 0.5-2h to preliminarily obtain a uniformly dispersed dark brown graphene oxide aqueous dispersion; and the mixture is stirred at a rate of 3000r / min for 24h at room temperature to obtain an L-tryptophan modified graphene oxide dispersion.

[0087] Preparation of component A: Add modified diphenylmethane diisocyanate into a reactor, react for 3 h at 60 °C in a nitrogen atmosphere, then add DBGA and modified graphene in sequence, and stir at a rate of 2500 r / min for 4 h to obtain component A with an NCO value of 12% and a viscosity of 750 mPa·s.

[0088] Component B raw materials (weight parts): The raw materials of component B include 35 parts of polyaspartic acid resin, 1 part of ultraviolet light absorber, 2 parts of light stabilizer, 1 part of azobisisobutyronitrile AIBN, 3-10 parts of nano titanium dioxide, 2 parts of fluorocarbon modified acrylic leveling agent AKN-3600, 2 parts of defoamer DU-964, and 5 parts of silane coupling agent KH550;

[0089] Preparation of polyaspartic acid resin: 1g of polysuccinimide was placed in a beaker containing 10mL of N,N'-dimethylformamide, fully dissolved in a 35℃ water bath for 2h, then 40μL of KH-550 silane coupling agent was added, the temperature was raised to 50℃, and the reaction was carried out under constant temperature stirring (speed 100r / min) for 3h. After the reaction, 10mL of anhydrous ethanol was used for precipitation, and the mixture was washed repeatedly for 3 times to obtain powdered modified polysuccinimide. 1g of modified polysuccinimide was dispersed in a beaker containing 10mL of deionized water, and 2mol / L NaOH solution was added dropwise in a 35℃ water bath, and the pH of the solution was maintained at 9-10 and no longer changed. Then, a certain amount of carboxymethyl cellulose was weighed and placed in the reaction solution, stirred (speed 100 r / min) for gelatinization for 30 min, 0.5% (based on acrylic acid) of KPS, a certain amount of acrylic acid with a neutralization degree of 70%, and 0.1% (based on acrylic acid) of N,N'-methylenebisacrylamide were added in sequence, nitrogen was passed, and stirring (speed 100 r / min) was stopped for 10 min. The mixture was allowed to stand at 70°C for 3 h to react. The product was placed in an oven and dried at 70°C for 24 h, and then crushed to obtain a solid powder modified polyaspartic acid / polyacrylic acid / carboxymethyl cellulose ternary composite highly absorbent resin.

[0090] Preparation of component B: Add the raw materials except the auxiliary agent into the reactor, stir at a rate of 2000 r / min for 30 min, heat to 90°C and heat for 3 h, then add ethyl acetate, leveling agent AKN-3600, defoaming agent DU-964 and silane coupling agent KH550 in sequence, and stir at a rate of 2000 r / min for 20 min to obtain component B.

[0091] Preparation of polyaspartic acid polyurea coating: At 60°C, component A and component B were mixed evenly in a dynamic mixing chamber, and then sprayed by a high-pressure sprayer. After curing, a modified perfluoropolyether grease was sprayed on the surface by a high-pressure sprayer to obtain an anti-aging and low-adhesion polyurea coating for marine equipment. According to the prescribed conditions of GB9278-08-T coating sample state adjustment and test temperature and humidity, the polyurea coating was placed for 7 days and then the performance test was carried out. The test results are shown in Table 1.

[0092] Example 2

[0093] The mass ratio of component A to component B is: 1:1.3;

[0094] Component A raw materials (parts by weight)

[0095] 50 parts of modified isophorone diisocyanate, 50 parts of biuret, 28 parts of modified graphene oxide, 9 parts of modified carbon nanofibers, and 10 parts of n-butyl acetate.

[0096] Preparation of modified isophorone diisocyanate: In a nitrogen-protected three-necked flask, 2 g of the carbon nanofiber CNF-OH with hydroxyl groups on the surface prepared in Example 1 was added to 200 g of isophorone diisocyanate, and ultrasonic treatment was performed at 30 kHz for 20 min, and then stirred at a rate of 2000 r / min for 6 h to obtain modified isophorone diisocyanate; Preparation of modified isophorone diisocyanate: In a nitrogen-protected three-necked flask, 100 g of isophorone diisocyanate was mixed with 100 g of biuret, and ultrasonic treatment was performed at 25 kHz for 10 min, and then 2 g of the carbon nanofiber CNF-OH with hydroxyl groups on the surface prepared in Example 1 was added thereto, and ultrasonic treatment was performed at 25 kHz for 20 min, and then stirred at a rate of 2000 r / min for 6 h to obtain modified isophorone diisocyanate;

[0097] Preparation of component A: Add modified isophorone diisocyanate into a reactor, react for 3 h at 60 °C in a nitrogen atmosphere, then add modified carbon nanofibers and n-butyl acetate in sequence, stir at a rate of 2500 r / min for 4 h to obtain component A with an NCO value of 11% and a viscosity of 730 mPa·s.

[0098] Component B raw materials (parts by weight):

[0099] Preparation of component B: Add the raw materials except the auxiliary agent into the reactor, stir at a rate of 2000 r / min for 30 min, heat to 90°C and heat for 3 h, then add ethyl acetate, leveling agent AKN-3600, defoaming agent DU-964 and silane coupling agent KH550 in sequence, and stir at a rate of 2000 r / min for 20 min to obtain component B.

[0100] Preparation of polyaspartic acid polyurea coating: At 70°C, component A and component B were mixed evenly in a dynamic mixing chamber, and then sprayed with a high-pressure sprayer. After curing, modified perfluoropolyether grease was sprayed to obtain a polyurea coating with anti-aging and low adhesion properties suitable for marine installations. According to the specified conditions of GB9278-08-T coating sample state adjustment and test temperature and humidity, the polyurea coating was placed for 7 days and then the performance test was carried out. The test results are shown in Table 1.

[0101] Example 3

[0102] The mass ratio of component A to component B is: 1:1.5;

[0103] Component A raw materials (parts by weight):

[0104] 50 parts of modified hexamethylene diisocyanate, 25 parts of modified graphene oxide, and 9 parts of n-butyl acetate.

[0105] Preparation of modified hexamethylene diisocyanate: In a nitrogen-protected three-necked flask, 100 g of hexamethylene diisocyanate and 100 g of biuret were mixed, and then 2 g of carbon nanofiber CNF-OH with hydroxyl groups on the surface prepared in Example 1 was added thereto, and the mixture was ultrasonically treated at 25 kHz for 20 min, and then stirred at a rate of 2000 r / min for 6 h to obtain modified hexamethylene diisocyanate;

[0106] Preparation of component A: Add modified hexamethylene diisocyanate and biuret into a reactor, react for 3 hours at 60°C in a nitrogen atmosphere, then add n-butyl acetate, and stir at a rate of 2000 r / min for 4 hours to obtain component A with an NCO value of 11% and a viscosity of 740 mPa·s.

[0107] Component B raw materials (parts by weight):

[0108] The raw materials for component B include 45 parts of polyaspartic acid resin, 2 parts of ultraviolet light absorber, 5 parts of light stabilizer, 1 part of azobisisobutyronitrile AIBN, 8 parts of modified nano titanium dioxide, 2 parts of acrylic leveling agent AKN-3600, 43 parts of defoamer DU-96, and 4 parts of silane coupling agent KH550 by weight.

[0109] Preparation of component B: Add the raw materials except the auxiliary agent into the reactor, stir at a rate of 2000 r / min for 30 min, heat to 90°C and heat for 3 h, then add ethyl acetate, leveling agent AKN-3600, defoaming agent DU-964 and silane coupling agent KH550 in sequence, and stir at a rate of 2000 r / min for 20 min to obtain component B.

[0110] Preparation of polyaspartic acid polyurea: Component A and component B were mixed evenly in a dynamic mixing chamber at 80°C, and then sprayed with a high-pressure sprayer. After curing, modified perfluoropolyether grease was sprayed to obtain a polyurea coating with anti-aging and low adhesion properties suitable for marine equipment. According to the specified conditions of GB9278-08-T coating sample state adjustment and test temperature and humidity, the polyurea coating was placed for 7 days and then subjected to performance testing. The test results are shown in Table 1.

[0111] Table 1 Performance test results of polyurea coatings prepared in Examples 1 to 3

[0112] Example 1 Example 2 Example 3 Tensile strength(MPa) 40 38 35 Artificially accelerated aging 1500 1500 1500 Resistance to 5% NaOH (23±2)℃(h) 168 156 150 Salt spray resistance(h) 2000 2000 2000 <![CDATA[Resistance to 5% H2SO4 at (23 ± 2) °C (h)]]> 168 156 150 Adhesion, 45 steel (MPa) 16.57 18.67 17.56 Contact angle (°) 153 150 155 Adhesion of coating to ice (KPa) 15 10 12

[0113] It can be seen from the above embodiments that the anti-aging and low-adhesion composite coating for marine equipment provided by the present invention has strong anti-aging, corrosion resistance, and anti-icing properties, a tensile strength of 40MPa, artificial accelerated aging for 1500h, resistance to 5% NaOH for 168H, resistance to 5% H2SO4 for 168h, a contact angle of 153°, an adhesion to 45 steel of 16.57MPa, salt spray resistance of 2000h, and an adhesion to ice of 10KPa.

[0114] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0115] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. An anti-aging low-adhesion composite coating suitable for marine equipment, characterized in that: After spraying polyaspartic acid polyurea on the surface of the substrate, a layer of modified perfluoropolyether grease is then coated on the surface, wherein the modified perfluoropolyether grease is obtained by adding nano hexagonal boron nitride to the perfluoropolyether grease; The polyaspartic acid polyurea is composed of component A and component B; the mass ratio of component A to component B is 1:1.2-1.5; The raw materials for preparing the component A include 35 to 50 parts of modified isocyanate, 15 to 30 parts of modified graphene oxide and 1 to 10 parts of diluent by weight; the modified isocyanate is prepared by mixing isocyanate and biuret in a mass ratio of 1:1 and then adding modified carbon nanofibers to mix; the preparation method of the modified graphene oxide is: modifying graphene oxide with an L-tryptophan solution to obtain modified graphene oxide; The raw materials for preparing the component B include 30-50 parts of polyaspartic acid resin, 2-5 parts of dispersant, 1-3 parts of ultraviolet light absorber, 2-5 parts of light stabilizer, 1-10 parts of diluent, 3-10 parts of modified nano titanium dioxide and 10-20 parts of auxiliary agent by weight; the polyaspartic acid resin is a modified polyaspartic acid / polyacrylic acid / carboxymethyl cellulose ternary composite highly absorbent resin, and the preparation method of the modified polyaspartic acid / polyacrylic acid / carboxymethyl cellulose ternary composite highly absorbent resin is as follows: 1g of polysuccinimide is placed in a beaker containing 10mL of N,N'-dimethylformamide, fully dissolved in a 35°C water bath for 2h, and then 40μL of KH-550 silane coupling agent, heated to 50℃, stirred at constant temperature, reacted at a speed of 100r / min for 3h, precipitated with 10mL anhydrous ethanol after the reaction, washed repeatedly 3 times to obtain powdered modified polysuccinimide; 1g of modified polysuccinimide was dispersed in a beaker containing 10mL deionized water, and 2mol / L NaOH solution, maintaining the pH of the solution at 9-10 and no longer changing; then, weighing carboxymethyl cellulose in the reaction solution and stirring at a speed of 100 r / min, gelatinizing for 30 min, sequentially adding KPS with a mass fraction of acrylic acid of 0.5%, acrylic acid with a neutralization degree of 70%, and N,N'-methylenebisacrylamide with a mass fraction of acrylic acid of 0.1%, passing nitrogen, stirring at a speed of 100 r / min for 10 min and stopping, standing and reacting at 70°C for 3 h, placing the product in an oven at 70°C for 24 h, and crushing to obtain a solid powder modified polyaspartic acid / polyacrylic acid / carboxymethyl cellulose ternary composite highly absorbent resin.

2. The anti-aging low-adhesion composite coating suitable for marine equipment according to claim 1, characterized in that: The preparation method of the modified carbon nanofiber is: using methyltrimethoxysilane to modify the carbon nanofiber CNF-OH with hydroxyl groups on the surface to obtain the modified carbon nanofiber.

3. The anti-aging low-adhesion composite coating suitable for seawear according to claim 1, characterized in that: The modified nano titanium dioxide is prepared by mixing liquid titanium dioxide with a sodium aluminate aqueous solution to obtain the modified nano titanium dioxide.

4. The anti-aging low-adhesion composite coating suitable for seawear according to claim 1, characterized in that: The diluents in component A and component B independently include propylene carbonate or n-butyl acetate; the auxiliary agent includes 7 to 10 parts of ethyl acetate, 2 to 3 parts of leveling agent, 1 to 2 parts of defoaming agent and 2 to 5 parts of silane coupling agent in parts by weight.

5. The method for preparing the anti-aging low-adhesion composite coating suitable for seawear according to any one of claims 1 to 4, characterized in that: At 60-80°C, component A and component B are mixed and then sprayed. After curing, modified perfluoropolyether lubricating ester is sprayed on the surface to obtain an anti-aging and low-adhesion composite coating suitable for marine equipment.

6. The use of the anti-aging low-adhesion composite coating suitable for sea equipment according to claim 1, characterized in that: The prepared marine-suitable anti-aging and low-adhesion composite coating is applied on the surface of marine equipment.