Marine anticorrosive coating and preparation method thereof

Abstract

The present invention provides a marine anti-corrosion coating and a preparation method thereof, belonging to the technical field of marine anti-corrosion coatings. The present invention utilizes irradiation-modified polytetrafluoroethylene to improve the anti-corrosion effect of the anti-corrosion coating; a polyphenol compound loaded with copper oxide modifies graphene oxide, which can evenly distribute the copper oxide in the anti-corrosion coating and improve the antibacterial effect; lithium ions dissociated from lithium-containing phosphates can act as cathode inhibitors, causing the metal to react with oxygen, water, and the like in the environment, thereby forming a passivation layer to improve corrosion resistance; layered two-dimensional fillers can form a barrier effect in the coating and can also construct a ternary synergistic anti-corrosion effect with modified graphene and nanocellulose, thereby improving the corrosion resistance of the anti-corrosion coating; nanocellulose has good interfacial compatibility with epoxy resin and modified graphene, can improve the flexibility of the coating, improve impact resistance, and solve the problem of easy cracking caused by the high brittleness of epoxy resin.

Description

Technical Field

[0001] The present invention relates to the technical field of marine anti-corrosion coatings, and in particular to a marine anti-corrosion coating and a preparation method thereof. Background Art

[0002] The marine environment has a significant corrosive effect on coastal facilities. Currently, the primary method of protecting marine engineering projects is to apply marine anti-corrosion coatings to protect against seawater corrosion. Marine anti-corrosion coatings are generally divided into primers, intermediate coatings, and topcoats. The main function of primers is to prevent rust and enhance the adhesion of the coating to the metal surface. Common examples include organic zinc-rich coatings and inorganic zinc-rich coatings. Intermediate coatings have good compatibility with primers and their main function is to increase the thickness of the paint film, enhance the paint layer, and provide good water resistance, weather resistance, and chemical solvent resistance. The main functions of topcoats include decoration, weather resistance, anti-aging, and corrosion protection.

[0003] Currently, the most commonly used intermediate and topcoats include epoxy coatings, polyurethane coatings, chlorinated rubber coatings, fluorocarbon resins, and polysiloxane coatings. Epoxy coatings offer excellent adhesion and resistance to corrosive media such as acids, alkalis, salts, and solvents, enabling the resulting anti-corrosion coating to effectively resist seawater erosion and salt spray corrosion. However, epoxy coatings have poor flexibility and are prone to cracking when impacted or deformed. These microcracks can cause severe localized corrosion in marine environments containing chloride ions, leading to the coating's shedding. Furthermore, sulfate-reducing bacteria and saprophytes in marine environments adhere to the coating surface, causing bacterial corrosion and degrading the coating's corrosion resistance.

[0004] Therefore, there is an urgent need to provide a marine anti-corrosion coating with good impact resistance and corrosion resistance. Summary of the Invention

[0005] The object of the present invention is to provide a marine anti-corrosion coating with good impact resistance and corrosion resistance and a preparation method thereof.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a marine anticorrosive coating, which comprises the following components, measured by weight: 25-75 parts of epoxy resin, 15-30 parts of radiation-modified polytetrafluoroethylene, 5-10 parts of modified graphene, 2-10 parts of lithium-containing phosphate, 2-10 parts of layered two-dimensional filler, 1-5 parts of cationic modified nanocellulose, 0.1-1 parts of leveling agent, 10-20 parts of curing agent and 200-500 parts of diluent;

[0008] The modified graphene is a copper oxide-loaded polyphenol compound-modified graphene oxide.

[0009] Preferably, the epoxy resin is bisphenol A epoxy resin.

[0010] Preferably, the preparation method of the copper oxide-loaded polyphenol compound-modified graphene oxide comprises:

[0011] (1) mixing a polyphenol compound, graphene oxide and water, and performing a reduction reaction to obtain polyphenol-modified graphene oxide;

[0012] (2) The polyphenol-modified graphene oxide obtained in step (1) is mixed with a soluble copper salt and a solvent to obtain a suspension, the pH value of the suspension is adjusted to 6-8, and then reacted and aged in sequence to obtain a polyphenol compound-modified graphene oxide loaded with copper oxide.

[0013] Preferably, the polyphenol compound in step (1) includes one or more of quercetin, anthocyanin and catechin.

[0014] Preferably, in step (1), the mass ratio of the polyphenol compound to graphene oxide is 1-10:1.

[0015] Preferably, the reaction temperature in step (2) is 85-90° C., and the reaction time is 30-60 min.

[0016] Preferably, the lithium phosphate comprises one or both of lithium iron phosphate and lithium manganese phosphate.

[0017] Preferably, the layered two-dimensional filler includes one or more of tungsten disulfide, graphite and talc.

[0018] Preferably, the nanocellulose in the cationic modified nanocellulose comprises one or more of cellulose nanofibers, cellulose nanowhiskers and bacterial nanocellulose.

[0019] The present invention also provides a method for preparing the marine anti-corrosion coating described in the above technical solution, comprising: mixing epoxy resin, irradiation-modified polytetrafluoroethylene, modified graphene, lithium-containing phosphate, layered two-dimensional filler, cationic modified nanocellulose, leveling agent, curing agent and diluent to obtain the marine anti-corrosion coating.

[0020] The invention provides a marine anti-corrosion coating, which comprises the following components in parts by weight: 25-75 parts of epoxy resin, 15-30 parts of radiation-modified polytetrafluoroethylene, 5-10 parts of modified graphene, 2-10 parts of lithium-containing phosphate, 2-10 parts of layered two-dimensional fillers, 1-5 parts of cationic modified nanocellulose, 0.1-1 parts of a leveling agent, 10-20 parts of a curing agent, and 200-500 parts of a diluent; the modified graphene is graphene oxide modified by a polyphenol compound loaded with copper oxide. The marine anticorrosion coating provided by the present invention includes irradiation-modified polytetrafluoroethylene, which has good interface bonding with epoxy resin; moreover, the irradiation-modified polytetrafluoroethylene can reduce the attachment of bacteria and microorganisms, reduce bacterial corrosion, and improve the anticorrosion effect of the anticorrosion coating; the marine anticorrosion coating provided by the present invention includes polyphenol compound-modified graphene oxide loaded with copper oxide, which can improve the dispersibility of graphene in the anticorrosion coating; moreover, loading copper oxide on the polyphenol compound-modified graphene oxide can make the copper oxide uniformly distributed in the anticorrosion coating, improve the antibacterial effect, reduce bacterial corrosion, and improve the anticorrosion effect of the anticorrosion coating; the marine anticorrosion coating provided by the present invention The present invention includes lithium-containing phosphates, the dissociated lithium ions of which can react with oxygen, water, etc. in the environment to form a passivation layer to improve the corrosion resistance; the marine anti-corrosion coating provided by the present invention includes a layered two-dimensional filler, the layered two-dimensional structure forms a barrier effect in the anti-corrosion coating, and can also construct a ternary synergistic anti-corrosion effect with modified graphene and cationic modified nanocellulose, thereby improving the corrosion resistance of the anti-corrosion coating; the marine anti-corrosion coating provided by the present invention is added with cationic modified nanocellulose, which has rich functional groups and good interface compatibility with epoxy resin and modified graphene, thereby improving the flexibility of the coating and the impact resistance of the anti-corrosion coating, thereby solving the problem of easy cracking caused by the large brittleness of epoxy resin. The results of the examples show that the anti-corrosion coating formed by the marine anti-corrosion coating provided by the present invention not only has excellent impact resistance, but also has excellent anti-corrosion effect. DETAILED DESCRIPTION

[0021] The present invention provides a marine anticorrosive coating, which comprises the following components, measured by weight: 25-75 parts of epoxy resin, 15-30 parts of radiation-modified polytetrafluoroethylene, 5-10 parts of modified graphene, 2-10 parts of lithium-containing phosphate, 2-10 parts of layered two-dimensional filler, 1-5 parts of cationic modified nanocellulose, 0.1-1 parts of leveling agent, 10-20 parts of curing agent and 200-500 parts of diluent;

[0022] The modified graphene is a copper oxide-loaded polyphenol compound-modified graphene oxide.

[0023] In the present invention, unless otherwise specified, the raw materials used in the present invention are all commercially available products in the art.

[0024] The marine anticorrosive coating provided by the present invention comprises 25 to 75 parts by weight of epoxy resin. As one embodiment of the present invention, the epoxy resin may be in an amount of 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, or 75 parts by weight. In the present invention, the epoxy resin is preferably a bisphenol A epoxy resin. In an embodiment of the present invention, the epoxy resin may be E51. The present invention utilizes epoxy resin as a film-forming substance for the marine anticorrosive coating.

[0025] Based on 25 to 75 parts by weight of epoxy resin, the ocean anti-corrosion coating provided by the present invention includes 15 to 30 parts by weight of radiation-modified polytetrafluoroethylene. As an embodiment of the present invention, the weight of the radiation-modified polytetrafluoroethylene can be 15 parts, 20 parts, 25 parts or 30 parts. In an embodiment of the present invention, the particle size of the radiation-modified polytetrafluoroethylene is preferably 500 nm; the model of the radiation-modified polytetrafluoroethylene is preferably TF-9207, and the source is preferably Dongguan Taotao Plastic Raw Materials Co., Ltd. The present invention uses the above-mentioned radiation-modified polytetrafluoroethylene nanopowder, which has good dispersibility and good compatibility with epoxy resin.

[0026] The present invention has no particular limitation on the preparation method of the radiation-modified polytetrafluoroethylene, and any conventional method for radiation-modified polytetrafluoroethylene can be used. In the present invention, the preparation method of the radiation-modified polytetrafluoroethylene preferably comprises: subjecting polytetrafluoroethylene to electron beam irradiation to obtain the radiation-modified polytetrafluoroethylene.

[0027] In an embodiment of the present invention, the model of the polytetrafluoroethylene is preferably TF-9207; and the particle size of the polytetrafluoroethylene is preferably 500 nm.

[0028] In the present invention, the irradiation dose of the electron beam irradiation is preferably 50 to 200 KGy. As an embodiment of the present invention, the irradiation dose of the electron beam irradiation can be 50 KGy, 100 KGy, 150 KGy or 200 KGy.

[0029] In the present invention, the electron beam irradiation time is preferably 6 to 12 hours. As an embodiment of the present invention, the electron beam irradiation time can be 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours.

[0030] In the present invention, the beam energy of the electron beam irradiation is preferably 0.5-5 MeV. As an embodiment of the present invention, the beam energy of the electron beam irradiation can be 0.5 MeV, 1 MeV, 2 MeV, 3 MeV, 4 MeV or 5 MeV.

[0031] The marine anti-corrosion coating provided by the present invention includes 5 to 10 parts of modified graphene, based on 25 to 75 parts by weight of epoxy resin. As one embodiment of the present invention, the modified graphene may be 5, 6, 7, 8, 9, or 10 parts by weight. In the present invention, the modified graphene is a polyphenol compound-modified graphene oxide loaded with copper oxide. The polyphenol compound-modified graphene oxide can improve the dispersibility of the graphene in the coating. Loading copper oxide on the polyphenol compound-modified graphene oxide can uniformly distribute the copper oxide in the anti-corrosion coating, thereby enhancing the antibacterial effect, reducing bacterial corrosion, and improving the anti-corrosion effect of the anti-corrosion coating.

[0032] In the present invention, the diameter of the copper oxide in the polyphenol compound-modified graphene oxide loaded with copper oxide is preferably 40 to 60 nm, more preferably 40 to 50 nm. The diameter of the copper oxide in the modified graphene oxide provided by the present invention is within the above range, which has a better bactericidal effect.

[0033] In the present invention, the mass ratio of copper oxide to polyphenol-modified graphene oxide in the copper oxide-loaded polyphenol compound-modified graphene oxide is preferably 1 to 8:1. Controlling the mass ratio of the copper oxide to polyphenol-modified graphene oxide within the above range facilitates uniform distribution of copper oxide in the polyphenol-modified graphene oxide.

[0034] In the present invention, the method for preparing the copper oxide-loaded polyphenol compound-modified graphene oxide preferably comprises:

[0035] (1) mixing a polyphenol compound, graphene oxide and water, and performing a reduction reaction to obtain polyphenol-modified graphene oxide;

[0036] (2) The polyphenol-modified graphene oxide obtained in step (1) is mixed with a soluble copper salt and a solvent to obtain a suspension, the pH value of the suspension is adjusted to 6-8, and then reacted and aged in sequence to obtain a polyphenol compound-modified graphene oxide loaded with copper oxide.

[0037] In the present invention, the polyphenol compound, graphene oxide and water are preferably mixed and then subjected to a reduction reaction to obtain polyphenol-modified graphene oxide.

[0038] In the present invention, the polyphenol compound preferably includes one or more of quercetin, anthocyanin and catechin. The present invention uses the above polyphenol compound, which has rich functional groups and can improve the dispersibility of graphene oxide in marine anti-corrosion coatings.

[0039] The present invention has no special limitation on the source and size of the graphene oxide, and conventional commercially available graphene oxide or graphene oxide prepared by conventional methods can be used.

[0040] In the present invention, the mass ratio of the polyphenol compound to graphene oxide is preferably 1 to 10: 1, more preferably 3 to 6: 1. By controlling the amount of the polyphenol compound to be used within the above range, the present invention can fully improve the dispersibility of graphene oxide in the marine anti-corrosion coating.

[0041] In the present invention, water serves as the dispersion medium. The amount of water used is not particularly limited and can be adjusted based on the amounts of the polyphenol compound and graphene oxide used, as long as sufficient reaction between the two is achieved. In an embodiment of the present invention, the ratio of the mass of the polyphenol compound to the volume of water can be (1-10) g:100 mL.

[0042] The present invention has no particular limitation on the method for mixing the polyphenol compound, graphene oxide and water, as long as the polyphenol compound and graphene oxide are fully dispersed in the water. In the present invention, the method for mixing the polyphenol compound, water and graphene oxide is preferably ultrasound.

[0043] In the present invention, the temperature of the reduction reaction is preferably 80-90° C., more preferably 85-90° C.; the time of the reduction reaction is preferably 2-6 hours, more preferably 3-5 hours. In the present invention, polyphenols modify graphene oxide through a reduction reaction.

[0044] In the present invention, after the reduction reaction, the resulting suspension is preferably filtered, washed, and dried in sequence to obtain polyphenol-modified graphene oxide. The present invention does not specifically limit the methods for filtering, washing, and drying; conventional filtering, washing, and drying methods may be employed. In an embodiment of the present invention, the washing agent may be deionized water; the drying temperature may be 80°C; and the drying time may be 24 hours.

[0045] After obtaining the polyphenol-modified graphene oxide, the present invention preferably mixes the polyphenol-modified graphene oxide, a soluble copper salt and a solvent to obtain a suspension, adjusts the pH value of the suspension to 6-8, and then sequentially reacts and ages to obtain a polyphenol compound-modified graphene oxide loaded with copper oxide.

[0046] The present invention does not particularly limit the type of solvent; any solvent that can fully disperse the polyphenol-modified graphene oxide and dissolve the copper salt can be used. In an embodiment of the present invention, the solvent can be anhydrous ethanol. In an embodiment of the present invention, when the mass of the polyphenol-modified graphene oxide is 1-10 g, the volume of the solvent can be 50-100 mL.

[0047] In the present invention, the soluble copper salt is preferably copper nitrate.

[0048] In the present invention, the mass ratio of the soluble copper salt to the polyphenol-modified graphene oxide is preferably 2 to 6:1, more preferably 4 to 5:1. Controlling the amounts of the two within the above range is more conducive to uniformly distributing the formed copper oxide in the polyphenol-modified graphene oxide.

[0049] The present invention does not particularly limit the method for mixing the polyphenol-modified graphene oxide, the soluble copper salt, and the solvent, as long as the polyphenol-modified graphene oxide can be fully dispersed in the solvent. In an embodiment of the present invention, the method for mixing the polyphenol-modified graphene oxide, the soluble copper salt, and the solvent is preferably ultrasonic.

[0050] In the present invention, the reagent for adjusting the pH value of the suspension is preferably a sodium hydroxide solution. In the present invention, the concentration of the sodium hydroxide solution is preferably 0.5 to 1 mol / L. By adjusting the pH value of the suspension to 6 to 8, the present invention can promote the reaction of copper salt to produce copper oxide.

[0051] In the present invention, the reaction temperature is preferably 85-90°C, more preferably 88-90°C; the reaction time is preferably 30-60 minutes, more preferably 40-60 minutes. In the present invention, the reaction is preferably carried out with stirring. By controlling the temperature and time within the above ranges, the present invention further promotes the adsorption of copper onto the polyphenol-modified graphene oxide, forming a precipitate that then decomposes into copper oxide.

[0052] In the present invention, the aging time is preferably 24 to 48 hours, more preferably 36 to 48 hours. The present invention can promote the growth of copper oxide crystals by aging by standing still.

[0053] In the present invention, after aging, the suspension obtained by aging is preferably filtered, washed, and dried in sequence to obtain the copper oxide-loaded polyphenol compound-modified graphene oxide. The present invention does not specifically limit the methods for filtration, washing, and drying; conventional filtration, washing, and drying methods may be employed. In an embodiment of the present invention, the washing agent may be deionized water; the drying temperature may be 60°C; and the drying time may be 48 hours.

[0054] The marine anti-corrosion coating provided by the present invention includes 2 to 10 parts of a lithium-containing phosphate, based on 25 to 75 parts by weight of the epoxy resin. As one embodiment of the present invention, the lithium-containing phosphate may be present in an amount of 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by weight. In the present invention, the lithium-containing phosphate preferably includes one or both of lithium iron phosphate and lithium manganese phosphate. In the present invention, the lithium ions dissociated from the lithium-containing phosphate can react with oxygen, water, and the like in the environment, thereby forming a passivation layer to improve corrosion resistance.

[0055] The marine anti-corrosion coating provided by the present invention includes 2 to 10 parts of a layered two-dimensional filler, based on 25 to 75 parts by weight of the epoxy resin. As an embodiment of the present invention, the layered two-dimensional filler may be present in an amount of 2, 3, 4, 5, 6, 7, 8, 9 or 10 parts by weight. The addition of a layered two-dimensional structure in the present invention can form a barrier effect in the coating, and can also construct a ternary synergistic anti-corrosion effect with modified graphene and cationic modified nanocellulose, thereby improving the corrosion resistance of the anti-corrosion coating.

[0056] In the present invention, the layered two-dimensional filler preferably comprises one or more of tungsten disulfide, graphite, and talc, more preferably tungsten disulfide or graphite. In the present invention, the particle size of the layered two-dimensional filler is preferably 50-100 nm, more preferably 60-100 nm.

[0057] The marine anticorrosive coating provided by the present invention includes 1 to 5 parts of cationic modified nanocellulose, based on 25 to 75 parts by weight of the epoxy resin. As an embodiment of the present invention, the nanocellulose may be present in an amount of 1, 2, 3, 4, or 5 parts by weight.

[0058] In the present invention, the nanocellulose in the cationic-modified nanocellulose preferably comprises one or more of cellulose nanofibers, cellulose nanowhiskers, and bacterial nanocellulose. The nanocellulose used in the present invention has abundant functional groups and good compatibility with epoxy resins. The present invention does not particularly limit the source of the nanocellulose; any commercially available product can be used.

[0059] In the present invention, the cationic modifier of the cationically modified nanocellulose is preferably 2,3-epoxypropyltrimethylammonium chloride.

[0060] In the present invention, the preparation method of the cationic modified nanocellulose preferably comprises: mixing a nanocellulose suspension, sodium hydroxide and 2,3-epoxypropyltrimethylammonium chloride to obtain a mixed slurry; and subjecting the mixed slurry to a modification reaction to obtain the cationic modified nanocellulose.

[0061] In the present invention, the mass concentration of the nanocellulose suspension is preferably 1-10%, more preferably 5-8%.

[0062] In the present invention, the mass concentration of sodium hydroxide in the mixed slurry is preferably 5-15%, more preferably 10-12%.

[0063] In the present invention, the mass concentration of 2,3-epoxypropyltrimethylammonium chloride in the mixed slurry is preferably 5-8%, more preferably 6-7%.

[0064] The present invention has no particular limitation on the method for mixing the nanocellulose suspension, sodium hydroxide and 2,3-epoxypropyltrimethylammonium chloride, as long as the nanocellulose suspension, sodium hydroxide and 2,3-epoxypropyltrimethylammonium chloride are evenly mixed to form a uniformly distributed mixed slurry.

[0065] In the present invention, the temperature of the modification reaction is preferably 50-140° C., more preferably 120-140° C.; the time of the modification reaction is preferably 3-6 h, more preferably 4-5 h.

[0066] The present invention preferably centrifuges, washes, dialyzes, and dries the system obtained from the modification reaction in sequence to obtain the cationic-modified nanocellulose. The present invention does not particularly limit the methods of centrifugation, washing, dialysis, and drying, as long as they can fully remove impurities remaining in the cationic-modified nanocellulose.

[0067] In the present invention, the diameter of the nanocellulose is preferably 30 to 80 nm. As an embodiment of the present invention, the diameter of the nanocellulose can be 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, or 80 nm. In the present invention, the length of the nanocellulose is preferably 1000 to 2000 nm, more preferably 1500 to 2000 nm. The use of nanocellulose of these sizes in the present invention is more conducive to improving the toughness of the anti-corrosion coating.

[0068] The marine anti-corrosion coating provided by the present invention includes 0.1 to 1 part of a leveling agent, based on 25 to 75 parts by weight of the epoxy resin. As one embodiment of the present invention, the leveling agent may be present in an amount of 0.1, 0.2, 0.5, 0.6, or 1 part by weight. In the present invention, the leveling agent is preferably PV88. The addition of a leveling agent can improve the leveling and uniformity of the marine anti-corrosion coating.

[0069] The marine anti-corrosion coating provided by the present invention includes 10 to 20 parts of a curing agent, based on 25 to 75 parts by weight of the epoxy resin. As one embodiment of the present invention, the curing agent may be present in an amount of 10, 12, 15, 16, or 20 parts by weight. In the present invention, the curing agent is preferably the cyclic aliphatic amine isophorone diamine. The addition of the curing agent in the present invention can accelerate the curing of the epoxy resin.

[0070] The marine anti-corrosion coating provided by the present invention includes 200 to 500 parts by weight of a diluent, based on 25 to 75 parts by weight of the epoxy resin. As one embodiment of the present invention, the diluent may be 200 parts, 300 parts, 400 parts, or 500 parts by weight. In the present invention, the diluent is preferably water and / or ethanol.

[0071] The marine anti-corrosion coating provided by the present invention utilizes irradiation-modified polytetrafluoroethylene to improve the anti-corrosion effect of the anti-corrosion coating; copper oxide is loaded on polyphenol compound-modified graphene oxide to improve the anti-corrosion effect of the anti-corrosion coating; lithium ions dissociated from lithium-containing phosphates can react with oxygen, water, etc. in the environment to form a passivation layer to improve the corrosion resistance; layered two-dimensional fillers can construct a ternary synergistic anti-corrosion effect with modified graphene and cationically modified nanocellulose, thereby improving the corrosion resistance of the anti-corrosion coating; cationically modified nanocellulose has good interface compatibility with epoxy resin and modified graphene, and can also improve the flexibility of the anti-corrosion coating, improve the impact resistance of the anti-corrosion coating, and solve the problem of easy cracking caused by the large brittleness of epoxy resin.

[0072] The present invention also provides a method for preparing the marine anti-corrosion coating described in the above technical solution, comprising: mixing epoxy resin, irradiation-modified polytetrafluoroethylene, modified graphene, lithium-containing phosphate, layered two-dimensional filler, cationic modified nanocellulose, leveling agent, curing agent and diluent to obtain the marine anti-corrosion coating.

[0073] In the present invention, the method for mixing the epoxy resin, radiation-modified polytetrafluoroethylene, modified graphene, lithium-containing phosphate, layered two-dimensional filler, cationic modified nanocellulose, leveling agent, curing agent and diluent is preferably: the epoxy resin, radiation-modified polytetrafluoroethylene, modified graphene, lithium-containing phosphate, layered two-dimensional filler, cationic modified nanocellulose, leveling agent and diluent are first stirred, and then the curing agent is added for second stirring.

[0074] In the present invention, the rotation speed of the first stirring is preferably 300-500 rpm / min, more preferably 400-500 rpm / min; the first stirring time is preferably 2-5 hours, more preferably 3-4 hours. In the present invention, the rotation speed of the second stirring is preferably 200-500 rpm / min, more preferably 300-400 rpm / min; the second stirring time is preferably 10-20 minutes, more preferably 10-15 minutes. The present invention performs stirring under the above conditions, which can uniformly mix the components and obtain a uniformly mixed marine anti-corrosion coating.

[0075] The preparation method provided by the invention is simple to operate and easy to control, and can be used to prepare marine anticorrosive coatings on a large scale.

[0076] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some 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 making creative efforts are within the scope of protection of the present invention.

[0077] The preparation method of the copper oxide-loaded polyphenol compound used in the embodiment of the present invention is:

[0078] (1) After 6 g of quercetin, 1 g of graphene oxide and 100 mL of water were ultrasonically mixed, a reduction reaction was carried out at 85° C. for 4 h. The suspension obtained by the reduction reaction was filtered and washed with water in sequence, and then dried at 60° C. for 48 h to obtain polyphenol-modified graphene oxide;

[0079] (2) 1 g of the polyphenol-modified graphene oxide obtained in step (1) and 5 g of copper nitrate were dissolved in 50 mL of anhydrous ethanol, titrated to pH = 7 using 0.5 mol / L NaOH solution, and then reacted at 90°C for 60 min, aged for 48 h, filtered and washed with water, and dried at 60°C for 48 h to obtain polyphenol compound-modified graphene oxide loaded with copper oxide, with a particle size of 40~50 nm.

[0080] The preparation method of the cationic modified nanocellulose used in the embodiment of the present invention is as follows: a nanocellulose suspension (bacterial nanocellulose) with a mass concentration of 6%, sodium hydroxide and 2,3-epoxypropyltrimethylammonium chloride are uniformly mixed to obtain a mixed slurry; the mass concentration of sodium hydroxide in the mixed slurry is 8%; the mass concentration of 2,3-epoxypropyltrimethylammonium chloride in the mixed slurry is 5%; the mixed slurry is reacted at 130°C for 5 hours, and then centrifuged, washed, dialyzed and dried to obtain cationic modified nanocellulose.

[0081] The preparation method of the irradiation-modified polytetrafluoroethylene used in the embodiments of the present invention is as follows: polytetrafluoroethylene (TF-9207) is subjected to electron beam irradiation, wherein the irradiation dose of the electron beam irradiation is 100 KGy, the electron beam irradiation time is 8 hours, and the beam energy of the electron beam irradiation is 1 MeV; and irradiation-modified polytetrafluoroethylene-1 is obtained.

[0082] The preparation method of the irradiation-modified polytetrafluoroethylene used in the embodiment of the present invention is as follows: polytetrafluoroethylene (TF-9207) is subjected to electron beam irradiation, wherein the irradiation dose of the electron beam irradiation is 80 KGy, the electron beam irradiation time is 9 hours, and the beam energy of the electron beam irradiation is 1 MeV; and irradiation-modified polytetrafluoroethylene-2 ​​is obtained.

[0083] The preparation method of the irradiation-modified polytetrafluoroethylene used in the embodiments of the present invention is as follows: polytetrafluoroethylene (TF-9207) is subjected to electron beam irradiation, wherein the irradiation dose of the electron beam irradiation is 150 KGy, the electron beam irradiation time is 7 hours, and the beam energy of the electron beam irradiation is 1 MeV; and irradiation-modified polytetrafluoroethylene-3 is obtained.

[0084] Radiation-modified polytetrafluoroethylene-1, radiation-modified polytetrafluoroethylene-2 ​​and radiation-modified polytetrafluoroethylene-3 have similar bonding abilities with epoxy resins. Therefore, in the embodiments of the present invention, the radiation-modified polytetrafluoroethylene used is radiation-modified polytetrafluoroethylene-1.

[0085] Example 1

[0086] A marine anticorrosive coating, comprising, by weight, 45 parts of epoxy resin E51, 15 parts of irradiation-modified polytetrafluoroethylene, 6 parts of copper oxide-loaded polyphenol compound-modified graphene oxide, 4 parts of lithium iron phosphate, 5 parts of molybdenum disulfide, 3 parts of cationic-modified bacterial nanocellulose, 0.5 parts of leveling agent PV88, 15 parts of cyclic aliphatic amine isophorone diamine as a curing agent, and 300 parts of ethanol as a diluent;

[0087] The preparation method of the marine anticorrosive coating comprises: first stirring epoxy resin, irradiation-modified polytetrafluoroethylene, modified graphene, lithium-containing phosphate, layered two-dimensional filler, cationic-modified nanocellulose, leveling agent and diluent at 450 rpm / min for 3 hours, and then adding a curing agent and stirring for a second time at 450 rpm / min for 10 minutes.

[0088] Example 2

[0089] A marine anticorrosive coating, comprising, by weight, 60 parts of epoxy resin E51, 18 parts of radiation-modified polytetrafluoroethylene, 7 parts of copper oxide-loaded polyphenol compound-modified graphene oxide, 4 parts of lithium iron phosphate, 5 parts of molybdenum disulfide, 3 parts of cationic-modified bacterial nanocellulose, 0.5 parts of leveling agent PV88, 20 parts of cyclic aliphatic amine isophorone diamine as a curing agent, and 350 parts of ethanol as a diluent;

[0090] The preparation method of the marine anti-corrosion coating is the same as that of Example 1.

[0091] Example 3

[0092] A marine anticorrosive coating, comprising, by weight, 30 parts of epoxy resin E51, 15 parts of radiation-modified polytetrafluoroethylene, 6 parts of copper oxide-loaded polyphenol compound-modified graphene oxide, 3 parts of lithium iron phosphate, 3 parts of graphite, 3 parts of cellulose nanowhiskers, 0.5 parts of a leveling agent PV88, 10 parts of a cyclic aliphatic amine isophorone diamine curing agent, and 200 parts of ethanol as a diluent;

[0093] The preparation method of the marine anti-corrosion coating is the same as that of Example 1.

[0094] Comparative Example 1

[0095] A marine anticorrosive coating, comprising, by weight, 45 parts of epoxy resin E51, 15 parts of radiation-modified polytetrafluoroethylene, 6 parts of copper oxide-loaded polyphenol compound-modified graphene oxide, 4 parts of lithium iron phosphate, 5 parts of molybdenum disulfide, 0.5 parts of leveling agent PV88, 15 parts of cyclic aliphatic amine isophorone diamine as a curing agent, and 300 parts of ethanol as a diluent;

[0096] The preparation method of the marine anti-corrosion coating is the same as that of Example 1.

[0097] Comparative Example 2

[0098] A marine anticorrosive coating, comprising, by weight, 45 parts of epoxy resin E51, 15 parts of radiation-modified polytetrafluoroethylene, 6 parts of graphene oxide, 4 parts of lithium iron phosphate, 5 parts of molybdenum disulfide, 3 parts of cationic modified bacterial nanocellulose, 0.5 parts of leveling agent PV88, 15 parts of cyclic aliphatic amine isophorone diamine as a curing agent, and 300 parts of ethanol as a diluent;

[0099] The preparation method of the marine anti-corrosion coating is the same as that of Example 1.

[0100] Comparative Example 3

[0101] A marine anticorrosive coating, comprising, by weight, 45 parts of epoxy resin E51, 15 parts of polytetrafluoroethylene (TF-9207), 6 parts of copper oxide-loaded polyphenol compound-modified graphene oxide, 4 parts of lithium iron phosphate, 5 parts of molybdenum disulfide, 3 parts of cationic modified bacterial nanocellulose, 0.5 parts of leveling agent PV88, 15 parts of cyclic aliphatic amine isophorone diamine as a curing agent, and 300 parts of ethanol as a diluent;

[0102] The preparation method of the marine anti-corrosion coating is the same as that of Example 1.

[0103] Comparative Example 4

[0104] A marine anticorrosive coating, comprising, by weight, 45 parts of epoxy resin E51, 15 parts of radiation-modified polytetrafluoroethylene, 6 parts of copper oxide particles (10-50 nm), 4 parts of lithium iron phosphate, 5 parts of molybdenum disulfide, 3 parts of cationic modified bacterial nanocellulose, 0.5 parts of leveling agent PV88, 15 parts of cyclic aliphatic amine isophorone diamine as a curing agent, and 300 parts of water as a diluent;

[0105] The preparation method of the marine anti-corrosion coating is the same as that of Example 1.

[0106] Comparative Example 5

[0107] A marine anticorrosive coating, comprising, by weight, 45 parts of epoxy resin E51, 15 parts of radiation-modified polytetrafluoroethylene, 6 parts of copper oxide particles (10-50 nm), 4 parts of lithium iron phosphate, 5 parts of molybdenum disulfide, 3 parts of bacterial nanocellulose, 0.5 parts of leveling agent PV88, 15 parts of cyclic aliphatic amine isophorone diamine as a curing agent, and 300 parts of water as a diluent;

[0108] The preparation method of the marine anti-corrosion coating is the same as that of Example 1.

[0109] Test Example 1

[0110] The performance of the marine anticorrosive coatings obtained in Examples 1 to 3 and Comparative Examples 1 to 5 was tested, and the results are shown in Table 1:

[0111] Table 1 Performance test results of marine anticorrosive coatings obtained in Examples 1 to 3 and Comparative Examples 1 to 5

[0112]

[0113] The above results show that Comparative Example 1 exhibits significantly lower impact resistance and corrosion resistance compared to Example 1. This is because, compared to Example 1, Comparative Example 1 lacks the addition of cationic-modified nanocellulose, which provides a better interface between nanocellulose and modified graphene oxide, improving the flexibility of the anti-corrosion coating. Without the addition of nanocellulose, the anti-corrosion coating is prone to cracking under impact, and the presence of cracks reduces the coating's corrosion resistance.

[0114] Compared with Example 1, the antibacterial and corrosion resistance of Comparative Example 2 were both reduced. This is because Comparative Example 2 did not add a copper oxide-loaded polyphenol compound to modify the graphene oxide, which failed to utilize the barrier and electrical conductivity of graphene to reduce corrosion. At the same time, the bactericidal properties of copper oxide were not utilized, resulting in bacterial corrosion.

[0115] The antibacterial property of Comparative Example 3 is lower than that of Example 1. This is because the polytetrafluoroethylene in Comparative Example 3 was not irradiated, and its bonding with the epoxy resin of the coating was poor, resulting in the coating being unable to fully exert the anti-biological adhesion ability of polytetrafluoroethylene.

[0116] Compared with Example 1, the antibacterial activity of Comparative Example 4 is lower. This is because although copper oxide is added to the coating, the binding ability of copper oxide with other components of the coating is relatively poor, and the nano-scale copper oxide easily agglomerates and cannot be fully dispersed in the coating, which results in the antibacterial activity of the anti-corrosion coating of Comparative Example 4 being lower than that of Example 1.

[0117] Compared with Example 1, Comparative Example 5 shows slightly decreased adhesion, impact resistance, salt spray resistance, antibacterial properties, and corrosion resistance. This is because the cationic modification of the nanocellulose used in the present invention not only forms hydrogen bonds with cellulose fibers, but also bonds with the nanocellulose through a charge neutralization mechanism, thereby improving the strength of the coating. Furthermore, it enhances the interaction between the layered two-dimensional filler and the modified graphene, which is then reflected in the coating, improving various properties of the coating. Unmodified nanocellulose, on the other hand, cannot form this synergistic effect, resulting in the anti-corrosion coating of Comparative Example 5 having lower performance than that of Example 1.

[0118] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A marine anti-corrosion coating, characterized in that: The composition comprises the following components in parts by weight: 25-75 parts of epoxy resin, 15-30 parts of radiation-modified polytetrafluoroethylene, 5-10 parts of modified graphene, 2-10 parts of lithium-containing phosphate, 2-10 parts of layered two-dimensional filler, 1-5 parts of cationic modified nanocellulose, 0.1-1 parts of leveling agent, 10-20 parts of curing agent and 200-500 parts of diluent; The modified graphene is a copper oxide-loaded polyphenol compound-modified graphene oxide; The nanocellulose in the cationic modified nanocellulose includes one or more of cellulose nanofibers, cellulose nanowhiskers and bacterial nanocellulose; The cationic modifier of the cationic modified nanocellulose is 2,3-epoxypropyltrimethylammonium chloride.

2. The marine anticorrosive coating according to claim 1, characterized in that: The epoxy resin is bisphenol A epoxy resin.

3. The marine anticorrosive coating according to claim 1, characterized in that: The preparation method of the copper oxide-loaded polyphenol compound-modified graphene oxide comprises the following steps: (1) mixing a polyphenol compound, graphene oxide and water, and performing a reduction reaction to obtain polyphenol-modified graphene oxide; (2) The polyphenol-modified graphene oxide obtained in step (1) is mixed with a soluble copper salt and a solvent to obtain a suspension, the pH value of the suspension is adjusted to 6-8, and then reacted and aged in sequence to obtain a polyphenol compound-modified graphene oxide loaded with copper oxide.

4. The marine anticorrosive coating according to claim 3, characterized in that: The polyphenol compound in step (1) includes one or more of quercetin, anthocyanin and catechin.

5. The marine anticorrosive coating according to claim 3, characterized in that: In the step (1), the mass ratio of the polyphenol compound to the graphene oxide is 1-10:

1.

6. The marine anticorrosive coating according to claim 3, characterized in that: The reaction temperature in step (2) is 85-90° C., and the reaction time is 30-60 min.

7. The marine anticorrosive coating according to claim 1, characterized in that: The lithium-containing phosphate includes one or both of lithium iron phosphate and lithium manganese phosphate.

8. The marine anticorrosive coating according to claim 1, characterized in that: The layered two-dimensional filler is molybdenum disulfide.

9. The method for preparing the marine anticorrosive coating according to any one of claims 1 to 8, comprising: The marine anticorrosive coating is obtained by mixing epoxy resin, radiation-modified polytetrafluoroethylene, modified graphene, lithium-containing phosphate, layered two-dimensional filler, cationic modified nanocellulose, a leveling agent, a curing agent and a diluent.

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