High-water-resistance waterborne polyurethane marine coating and preparation method thereof

Abstract

The invention discloses a high-water-resistance waterborne polyurethane marine coating and a preparation method thereof, and belongs to the field of marine paints.The coating comprises a component A and a component B. The component A is prepared from, by weight, 50-60 parts of waterborne organic silicon modified polyurethane resin, 10-20 parts of fluorocarbon resin emulsion, 15-20 parts of nanometer reinforcing filler, 0.5-5.0 parts of polyurethane thickening agent, 0.1-0.3 part of defoaming agent, 0.2-0.5 part of wetting agent and 0.3-0.8 part of anti-settling agent; 0.3 to 0.8 part of a mildew preventive; and the component B comprises the following components in parts by weight: 0.3-1.0 part of an aziridine cross-linking agent and 2-3 parts of a dehydrating agent. When in use, the component A and the component B are mixed according to the weight ratio of 5: 1 and then are sprayed or rolled to form a coating with the dry film thickness of 80-150 microns, and the prepared high-water-resistance waterborne polyurethane marine coating has the advantages that the water absorption rate is reduced, the water resistance and the mechanical strength are improved, and the waterborne polyurethane marine coating with high water resistance, hardness and biological adhesion resistance is realized; meanwhile, low VOC and normal-temperature curing are realized, so that the application range of the coating is wider.

Description

Technical Field

[0001] The present invention relates to the technical field of ship coatings, and particularly relates to a high water-resistant waterborne polyurethane ship coating and a preparation method thereof. Background Art

[0002] In recent years, due to national policy encouragement and people's demands for healthy and environmentally friendly materials, the polyurethane coating industry has been increasingly developing towards the directions of environmental protection, water-based, high performance, and sustainable recyclability. Waterborne coatings have the advantages of being non-toxic, pollution-free, non-flammable, etc. compared with traditional solvent-based coatings, and are completely or basically solvent-free, which better meets the environmental protection requirements. Waterborne resins are compounded with film-forming auxiliaries, defoamers, leveling agents, dispersants, thickeners, preservatives, pigments and fillers, pH regulators, etc. to finally form applicable coating formulations, and are widely used in the fields of furniture, construction, floor, automobile, and ship, etc. In the waterborne paint formulation, the waterborne polyurethane base material is the key component that forms the paint film and determines the performance of the paint film. Waterborne polyurethane uses water as the dispersion medium, not only has the advantages of being non-toxic, pollution-free, and non-flammable, but also has certain flexibility, mechanical strength, wear resistance and other properties. It can also be compounded with various waterborne resins to improve performance and reduce costs, and is an important part of the sustainable development of adhesives in the future. As the main resin of waterborne polyurethane adhesives, the performance of waterborne polyurethane dispersions plays a decisive role.

[0003] With the strict restrictions on the emission of volatile organic compounds (VOCs) by environmental protection regulations, ship coatings are developing towards the directions of low pollution and high performance. Traditional solvent-based coatings are gradually being phased out due to the large amount of toxic VOCs they contain. Although waterborne coatings are environmentally friendly, their hardness and water resistance are insufficient, making it difficult to meet the long-term protection requirements of ships in the high salt fog and high humidity environment of the ocean. Although waterborne polyurethane coatings have the advantages of being non-toxic and safe, they are prone to problems such as swelling and decreased adhesion under long-term water immersion conditions, resulting in coating failure. Therefore, developing a waterborne polyurethane ship coating with both high water resistance, high hardness and environmental protection characteristics has become a technical problem that the industry urgently needs to break through.

[0004] Traditional solvent-based ship coatings have high levels of volatile organic compounds (VOCs), posing environmental pollution and health risks. Although waterborne polyurethane coatings are excellent in environmental protection, their water resistance, hardness, and anti-biofouling properties still cannot meet the long-term service requirements of ships (such as the insufficient water resistance of the low-viscosity adhesive described in Chinese Patent CN202211535917.2). By compounding waterborne binary polyurethane with fluorocarbon emulsion to improve hardness, the adhesion decreases by more than 20% after water immersion (>30 days).

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The object of the present invention is to provide a highly water-resistant waterborne polyurethane ship coating and its preparation method, which has both high water resistance, hardness and anti-biofouling properties, and at the same time realizes low VOC and room-temperature curing, thereby solving the above technical problems existing in the prior art.

[0007] The object of the present invention is achieved by the following technical solutions:

[0008] A highly water-resistant waterborne polyurethane ship coating, including component A and component B; wherein,

[0009] Component A is made of the following raw materials in parts by weight, including:

[0010]

[0011] Component B is made of the following raw materials in parts by weight, including:

[0012] Aziridine crosslinking agent 0.3 - 1.0 part,

[0013] Dehydrating agent 2 - 3 parts.

[0014] Furthermore, the silicone mass percentage content of the waterborne organosilicon-modified polyurethane resin in the above component A is 5% - 10%, and the hydroxyl value is 50 - 80 mg KOH / g, and the glass transition temperature is -20 - 10 °C.

[0015] Furthermore, the fluorocarbon resin emulsion in the above component A is a FEVE-type fluorocarbon emulsion, the fluorine element content ≥ 65%, the solid content is 45% - 50%, and the molecular weight is 8000 - 15000.

[0016] Furthermore, the nano-enhanced filler in the above component A is composed of 10 - 15 parts by weight of silicon carbide and 5 - 8 parts by weight of graphene oxide. Among them, the particle size of the silicon carbide is 50 - 100 nm, the purity ≥ 99.5%, and the surface is modified by the silane coupling agent KH-570;

[0017] The graphene oxide is pretreated with the silane coupling agent KH550, the specific surface area ≥ 500 m 2 / g, and the sheet thickness ≤ 5 nm.

[0018] Furthermore, the polyurethane thickener in the above component A is a non-ionic associative thickener, and the viscosity adjustment range at 25 °C is 2000 - 6000 mPa·s.

[0019] Furthermore, the defoaming agent in the above component A is a mineral oil-polyether composite defoaming agent, and its dynamic surface tension ≤ 25 mN / m.

[0020] Furthermore, the wetting agent in the above component A is a non-ionic fluorocarbon surfactant, and the dynamic contact angle ≤ 10°.

[0021] Furthermore, the anti-settling agent in the above-mentioned Component A is fumed silica, with a specific surface area of 200 - 400 m 2 / g;

[0022] The mildew-proof agent is an isothiazolinone compound, and the effective bacteriostatic concentration ≤ 50 ppm.

[0023] Furthermore, the aziridine cross-linking agent in the above-mentioned Component B is a trifunctional aziridine compound, and the functional group content ≥ 95%;

[0024] The dehydrating agent is tetraethyl orthosilicate, with a purity ≥ 99% and a water adsorption capacity ≥ 20%.

[0025] A preparation method of the above-mentioned high water-resistant waterborne polyurethane ship coating, characterized by comprising:

[0026] Taking each raw material of Component A and Component B according to the formula of the high water-resistant waterborne polyurethane ship coating described in the present invention;

[0027] Dispersing the raw materials of Component A in sequence at 30 - 40 °C and 800 - 1200 rpm for 60 - 90 minutes;

[0028] Premixing Component B and then aging it for 24 - 48 hours;

[0029] When in use, mixing Component A and Component B in a mass ratio of 5:1 and then spraying or roller-coating to form a coating with a dry film thickness of 80 - 150 μm, which is the prepared high water-resistant waterborne polyurethane ship coating.

[0030] Compared with the prior art, the high water-resistant waterborne polyurethane ship coating and its preparation method provided by the present invention have the following beneficial effects:

[0031] By using organosilicon to modify polyurethane in Component A to provide flexibility and a hydrophobic backbone, fluorocarbon resin endows the surface with a low surface energy, reduces the penetration of water molecules, and at the same time improves the coating hardness and weather resistance. The two form an interpenetrating network through hydrogen bonds and physical entanglement, improving the pigment dispersion efficiency and coating denseness, and enhancing water resistance; introducing a cross-linking network to strengthen the multiple self-crosslinking technology, constructing a three-dimensional cross-linking network, restricting the movement of molecular chains, reducing the water absorption rate, and enhancing water resistance and mechanical strength. Thus, a waterborne polyurethane ship coating with both high water resistance, hardness, and anti-biofouling properties is achieved, and at the same time, low VOC and room temperature curing are realized, making the coating application more extensive. The present invention improves the hydrophobicity and water resistance of the waterborne polyurethane ship coating by selecting a suitable modification method, optimizing the composition and cross-linking density of the organosilicon resin, and combining other modification technologies. Detailed implementation mode

[0032] The following clearly and completely describes the technical solutions in the embodiments of the present invention in combination with the specific content of the present invention; obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments, which does not constitute a limitation to the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0033] First, the following explanations are made for the terms that may be used in this article:

[0034] The term "and / or" means that either one or both of the two can be achieved. For example, X and / or Y means that it includes both the case of "X" or "Y" and the three cases of "X and Y".

[0035] The description of terms such as "comprising", "including", "containing", "having" or other similar semantics should be interpreted as non-exclusive inclusion. For example: including a certain technical feature element (such as raw materials, components, ingredients, carriers, dosage forms, materials, dimensions, parts, components, mechanisms, devices, steps, processes, methods, reaction conditions, processing conditions, parameters, algorithms, signals, data, products or articles, etc.) should be interpreted as including not only the clearly listed certain technical feature element, but also other technical feature elements well known in the art that are not clearly listed.

[0036] The term "consisting of" means excluding any technical feature elements not clearly listed. If this term is used in a claim, this term will make the claim a closed type, so that it does not include technical feature elements other than the clearly listed technical feature elements, except for related conventional impurities. If this term only appears in a certain clause of the claim, then it only limits the elements clearly listed in that clause, and the elements recorded in other clauses are not excluded from the overall claim.

[0037] The term "parts by mass" represents the mass ratio relationship between multiple components. For example: if it is described that component X is x parts by mass and component Y is y parts by mass, then it means that the mass ratio of component X to component Y is x:y; 1 part by mass can represent any mass. For example: 1 part by mass can be expressed as 1 kg or 3.1415926 kg, etc. The sum of the parts by mass of all components is not necessarily 100 parts, and can be greater than 100 parts, less than 100 parts or equal to 100 parts. Unless otherwise specified, the parts, ratios and percentages described in this article are by mass.

[0038] When concentration, temperature, pressure, size or other parameters are expressed in the form of a numerical range, the numerical range should be understood as specifically disclosing all ranges formed by the pairing of any upper limit value, lower limit value, and preferred value within the numerical range, regardless of whether the range is explicitly recorded; for example, if the numerical range "2 to 8" is recorded, then this numerical range should be interpreted as including ranges such as "2 to 7", "2 to 6", "5 to 7", "3 to 4 and 6 to 7", "3 to 5 and 7", "2 and 5 to 7", etc. Unless otherwise specified, the numerical ranges recorded herein include both their end values and all integers and fractions within the numerical range.

[0039] The solutions provided by the present invention will be described in detail below. The content not described in detail in the embodiments of the present invention belongs to the prior art well-known to those skilled in the art. For those conditions not specified in the embodiments of the present invention, they are carried out according to the conventional conditions in the art or the conditions recommended by the manufacturer. For the reagents or instruments not specified in the embodiments of the present invention for the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0040] An embodiment of the present invention provides a highly water-resistant waterborne polyurethane ship coating, including component A and component B; wherein, component A is made of the following raw materials in parts by weight, including:

[0041]

[0042]

[0043] Component B is made of the following raw materials in parts by weight, including:

[0044] Aziridine crosslinking agent 0.3 to 1.0 part;

[0045] Dehydrating agent 2 to 3 parts.

[0046] In some specific embodiments of the present invention, the silicone content of the waterborne organosilicon-modified polyurethane resin in component A is 5% to 10%, and the hydroxyl value is 50 to 80 mg KOH / g, and the glass transition temperature (Tg) is -20 to 10 °C.

[0047] In some specific embodiments of the present invention, the fluorocarbon resin emulsion in component A is a FEVE-type fluorocarbon emulsion, the fluorine element content is ≥65%, the solid content is 45% to 50%, and the molecular weight is 8000 to 15000.

[0048] In some specific embodiments of the present invention, the nano-enhanced filler in component A is composed of 10 to 15 parts by weight of silicon carbide and 5 to 8 parts by weight of graphene oxide; wherein, the particle size of the silicon carbide is 50 to 100 nm, the purity is ≥99.5%, and the surface is modified with a silane coupling agent KH-570;

[0049] The graphene oxide is pretreated with silane coupling agent KH550, and its specific surface area is ≥500 m 2 / g, and the thickness of its sheet is ≤5 nm.

[0050] In some specific embodiments of the present invention, the polyurethane thickener in component A is a non-ionic associative thickener, and the viscosity adjustment range at 25 °C is 2000~6000 mPa·s.

[0051] In some specific embodiments of the present invention, the defoamer in component A is a mineral oil-polyether composite defoamer, and the dynamic surface tension is ≤25 mN / m.

[0052] The wetting agent in component A is a non-ionic fluorocarbon surfactant, and the dynamic contact angle is ≤10°. The anti-settling agent is fumed silica, and its specific surface area is 200~400 m 2 / g.

[0053] The mildew-proof agent in component A is an isothiazolinone compound, and the effective antibacterial concentration is ≤50 ppm.

[0054] In some specific embodiments of the present invention, the aziridine crosslinking agent in component B is a trifunctional aziridine compound, and the functional group content is ≥95%.

[0055] In some specific embodiments of the present invention, the dehydrating agent in component B is tetraethyl orthosilicate (TEOS), the purity is ≥99%, and the water adsorption capacity is ≥20%.

[0056] The embodiments of the present invention also provide a preparation method of the above high water-resistant waterborne polyurethane ship coating, including:

[0057] Take the raw materials used in component A and component B respectively according to the formula;

[0058] (1) Disperse the raw materials of component A in sequence at 30~40 °C and 800~1200 rpm for 60~90 minutes;

[0059] (2) Premix component B and then cure it for 24~48 hours;

[0060] (3) Mix component A and component B in a mass ratio of 5:1, and then spray or roll coat to form a coating with a dry film thickness of 80~150 μm.

[0061] In order to more clearly show the technical solutions provided by the present invention and the technical effects produced, the following takes specific examples to describe in detail the solutions provided by the embodiments of the present invention.

[0062] Example 1

[0063] This embodiment provides a highly water-resistant waterborne polyurethane ship coating, including component A and component B. Among them,

[0064] Component A (each raw material is calculated by weight):

[0065] Waterborne organosilicon-modified polyurethane resin (organosilicon content 5%, hydroxyl value 60mg KOH / g) 55 parts;

[0066] FEVE fluorocarbon resin emulsion (fluorine content 68%, solid content 48%) 12 parts;

[0067] Nano-enhanced filler: silicon carbide (particle size 60nm, modified with KH570) 12 parts;

[0068] Graphene oxide (sheet thickness 3nm, treated with KH-550) 5 parts;

[0069] Polyurethane thickener (RM-2020) 0.8 parts;

[0070] Defoamer (BYK-024) 0.2 parts;

[0071] Wetting agent (TEGO Wet 270) 0.3 parts;

[0072] Anti-settling agent (Aerosil 200) 0.5 parts;

[0073] Mildew-proof agent (Kathon LX) 0.5 parts.

[0074] Component B (each raw material is calculated by weight):

[0075] Aziridine cross-linking agent (CX-100) 0.6 parts;

[0076] Dehydrating agent (TEOS) 2.5 parts.

[0077] The preparation method of the above highly water-resistant waterborne polyurethane ship coating includes the following steps:

[0078] (1) Component A is dispersed at 40°C and 1000 rpm for 60 minutes, and then sanded until the fineness is ≤20μm;

[0079] (2) Component B is premixed and then cured for 24 hours;

[0080] (3) Component A and component B are mixed at a weight ratio of 5:1, and sprayed onto the steel plate to form a dry film thickness of 100μm.

[0081] Table 1 shows the performance data of the coating in this embodiment:

[0082]

[0083]

[0084] Example 2

[0085] This example provides a highly water-resistant waterborne polyurethane ship coating, including component A and component B. Among them,

[0086] Component A (each raw material is calculated by weight):

[0087] Waterborne organosilicon-modified polyurethane resin (organosilicon content 8%, hydroxyl value 70mg KOH / g) 57 parts;

[0088] FEVE fluorocarbon resin emulsion (fluorine content 68%, solid content 48%) 12 parts;

[0089] Nano-enhanced filler: silicon carbide (particle size 60nm, modified with KH570) 10 parts;

[0090] Graphene oxide (sheet thickness 3nm, treated with KH-550) 6 parts;

[0091] Polyurethane thickener (RM-2020) 0.8 parts;

[0092] Defoamer (BYK-024) 0.2 parts;

[0093] Wetting agent (TEGO Wet 270) 0.3 parts;

[0094] Anti-settling agent (Aerosil 200) 0.5 parts;

[0095] Mildew-proof agent (Kathon LX) 0.5 parts.

[0096] Component B (each raw material is calculated by weight):

[0097] Aziridine cross-linking agent (CX-100) 0.6 parts;

[0098] Dehydrating agent (TEOS) 2.5 parts.

[0099] The preparation method of the above highly water-resistant waterborne polyurethane ship coating includes the following steps:

[0100] (1) Component A is dispersed at 40°C and 1000 rpm for 60 minutes, and then sanded to a fineness of ≤20μm;

[0101] (2) Component B is premixed and then cured for 24 hours;

[0102] (3) Component A and component B are mixed at a weight ratio of 5:1, and sprayed onto the steel plate to form a dry film thickness of 100μm.

[0103] Table 2 shows the performance data of the coating in this example:

[0104] Test Items Results Salt Spray Resistance No Corrosion after 2500 Hours Water Contact Angle 115° Flexibility (Axis Bar Bending) No Cracks at 1mm Wear Resistance Weight Loss of 10mg

[0105] Example 3

[0106] This example provides a highly water-resistant waterborne polyurethane ship coating, including component A and component B. Among them, component A (each raw material is calculated by weight):

[0107] Waterborne organosilicon-modified polyurethane resin (silicone content 5%, hydroxyl value 60mg KOH / g) 55 parts; FEVE fluorocarbon resin emulsion (fluorine content 68%, solid content 48%) 12 parts;

[0108] Nano-enhanced filler: silicon carbide (particle size 60nm, modified with KH570) 12 parts;

[0109] Graphene oxide (sheet thickness 3nm, treated with KH-550) 5 parts;

[0110] Polyurethane thickener (RM-2020) 0.8 parts;

[0111] Defoamer (BYK-024) 0.2 parts;

[0112] Wetting agent (TEGO Wet 270) 0.3 parts;

[0113] Anti-settling agent (Aerosil 200) 0.5 parts;

[0114] Mildew-proof agent (Kathon LX) 0.5 parts.

[0115] Component B (each raw material is calculated by weight):

[0116] Aziridine cross-linking agent (CX-100) 0.8 parts;

[0117] Dehydrating agent (molecular sieve powder, particle size 3μm) 2.5 parts.

[0118] The preparation method of the above highly water-resistant waterborne polyurethane ship coating includes the following steps:

[0119] (1) Component A is dispersed at 40°C and 1000 rpm for 60 minutes, and sanded to a fineness of ≤20μm;

[0120] (3) Component B is pre-mixed and then cured for 24 hours;

[0121] (3) Component A and component B are mixed at a ratio of 5:1 and sprayed onto the steel plate to form a dry film thickness of 100μm.

[0122] Table 3 shows the performance data of the coating in this example:

[0123] Test Items Results Surface Drying Time (25°C) 20 Minutes Through Drying Time 18 Hours Salt Spray Resistance No Corrosion after 2300 Hours Adhesion 5.5MPa

[0124] Comparative Example 1

[0125] This comparative example provides an aqueous polyurethane ship coating, and its preparation method may include the following steps: Component A (each raw material is in parts by weight):

[0126] Waterborne organosilicon-modified polyurethane resin (organosilicon content 5%, hydroxyl value 60 mg KOH / g) 60 parts, nano-enhanced filler: silicon carbide (particle size 60 nm, modified with KH570) 12 parts,

[0127] Graphene oxide (sheet thickness 3 nm, treated with KH-550) 5 parts,

[0128] Polyurethane thickener (RM-2020) 0.8 part,

[0129] Defoamer (BYK-024) 0.2 part,

[0130] Wetting agent (TEGO Wet 270) 0.3 part,

[0131] Anti-settling agent (Aerosil 200) 0.5 part,

[0132] Mildew-proof agent (Kathon LX) 0.5 part.

[0133] Component B (each raw material is in parts by weight):

[0134] Aziridine crosslinking agent (CX-100) 0.6 part,

[0135] Dehydrating agent (TEOS) 2.5 parts.

[0136] The preparation method of the coating in this comparative example is as follows:

[0137] (1) Component A is dispersed at 40 °C and 1000 rpm for 60 minutes, and sanded until the fineness is ≤ 20 μm;

[0138] (2) Component B is premixed and then cured for 24 hours;

[0139] (3) A:B is mixed at 5:1, sprayed onto the steel plate, and the dry film thickness is 100 μm.

[0140] Table 4 shows the performance comparison data between this Comparative Example 1 and Example 1:

[0141] Test Items Results of Comparative Example 1 Results of Example 1 Water Contact Angle 85° 112° Salt Spray Resistance Bubbling after 800 Hours No Corrosion after 2200 Hours Anti-Fouling Property (Ink Wiping) Obvious Residue No Residue

[0142] Comparative Example 2

[0143] This comparative example provides an aqueous polyurethane ship coating, and its preparation method may include the following steps: Component A (each raw material is in parts by weight):

[0144] 55 parts of waterborne silicone-modified polyurethane resin (silicone content 5%, hydroxyl value 60 mg KOH / g), 12 parts of FEVE fluorocarbon resin emulsion (fluorine content 68%, solid content 48%),

[0145] Nano-enhanced filler: 12 parts of silicon carbide (particle size 60 nm),

[0146] 5 parts of graphene oxide (lamellar thickness 3 nm),

[0147] 0.8 part of polyurethane thickener (RM-2020),

[0148] 0.2 part of defoamer (BYK-024),

[0149] 0.3 part of wetting agent (TEGO Wet 270),

[0150] 0.5 part of anti-settling agent (Aerosil 200),

[0151] 0.5 part of mildew-proof agent (Kathon LX).

[0152] Component B (each raw material is in parts by weight):

[0153] 0.6 part of aziridine cross-linking agent (CX-100),

[0154] 2.5 parts of dehydrating agent (TEOS).

[0155] The preparation method of the coating in this comparative example is as follows:

[0156] (1) Component A is dispersed at 40 °C and 1000 rpm for 60 minutes, and sanded until the fineness ≤ 20 μm;

[0157] (2) Component B is premixed and then cured for 24 hours;

[0158] (3) Component A: Component B is mixed at a weight ratio of 5:1, sprayed onto a steel plate, and the dry film thickness is 100 μm.

[0159] Table 5 shows the performance comparison data between this comparative example 2 and Example 1:

[0160] Test Items Results of Comparative Example 2 Results of Example 1 Adhesion 3.2MPa 5.8MPa Wear Resistance Weight Loss of 35mg Weight Loss of 12mg Storage Stability (30 Days) Layering and Precipitation No Sedimentation

[0161] In Comparative Example 1, no fluorocarbon resin was added, the contact angle decreased by 27°, and the salt spray resistance decreased by 62%, proving that the fluorocarbon resin is crucial for hydrophobicity and corrosion resistance. In Comparative Example 2, the unmodified nano-fillers led to a 45% decrease in adhesion and a 65% decrease in abrasion resistance, indicating that surface treatment is the key to enhancing interfacial bonding. In Example 3, by increasing cross-linking, the dry time was shortened to 18 hours (traditional waterborne coatings require more than 48 hours), meeting the time efficiency requirements for ship maintenance.

[0162] As described above, it is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims. The information disclosed in the background art part of this article is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or imply in any form that this information constitutes the prior art known to those skilled in the art.

Claims

1. A highly water-resistant waterborne polyurethane marine coating, characterized in that: Comprising component A and component B; wherein, Component A is made of the following raw materials in parts by weight, including: Component B is made of the following raw materials in parts by weight, including: 0.3-1.0 parts of aziridine crosslinking agent, 2 to 3 parts of dehydrating agent.

2. The highly water-resistant waterborne polyurethane marine coating according to claim 1, characterized in that: The water-based organosilicon-modified polyurethane resin in the component A has an organosilicon mass percentage of 5% to 10%, a hydroxyl value of 50 to 80 mg KOH / g, and a glass transition temperature of -20 to 10°C.

3. The highly water-resistant waterborne polyurethane marine coating according to claim 1, characterized in that: The fluorocarbon resin emulsion in the A component is a FEVE type fluorocarbon emulsion, with a fluorine content of ≥65%, a solid content of 45% to 50%, and a molecular weight of 8000 to 15000.

4. The highly water-resistant waterborne polyurethane marine coating according to claim 1, characterized in that: The nano-reinforced filler in component A is composed of 10 to 15 parts by weight of silicon carbide and 5 to 8 parts by weight of graphene oxide, wherein the silicon carbide has a particle size of 50 to 100 nm, a purity of ≥99.5%, and a surface modified by a silane coupling agent KH-570; The graphene oxide is pretreated with silane coupling agent KH550, and the specific surface area is ≥500m 2 / g, and its layer thickness is ≤5nm.

5. The highly water-resistant waterborne polyurethane marine coating according to any one of claims 1 to 4, characterized in that: The polyurethane thickener in the component A is a non-ionic associative thickener, and the viscosity adjustment range at 25° C. is 2000 to 6000 mPa·s.

6. The highly water-resistant waterborne polyurethane marine coating according to any one of claims 1 to 4, characterized in that: The defoamer in the component A is a mineral oil-polyether composite defoamer, and its dynamic surface tension is ≤25mN / m.

7. The highly water-resistant waterborne polyurethane marine coating according to any one of claims 1 to 4, characterized in that: The wetting agent in the component A is a non-ionic fluorocarbon surfactant with a dynamic contact angle of ≤10°.

8. The highly water-resistant waterborne polyurethane marine coating according to any one of claims 1 to 4, characterized in that: The anti-settling agent in component A is fumed silica with a specific surface area of ​​200 to 400 m 2 / g; The mildew inhibitor is an isothiazolinone compound, and the effective antibacterial concentration is ≤50ppm.

9. The highly water-resistant waterborne polyurethane marine coating according to any one of claims 1 to 4, characterized in that: The aziridine crosslinking agent in the B component is a trifunctional aziridine compound, and the functional group content is ≥95%; The dehydrating agent is tetraethyl orthosilicate, with a purity of ≥99% and a water adsorption capacity of ≥20%.

10. A method for preparing the highly water-resistant waterborne polyurethane marine coating according to any one of claims 1 to 9, characterized in that: include: The formula of the highly water-resistant waterborne polyurethane marine coating according to any one of claims 1 to 9 is as follows: Disperse the raw materials of component A in sequence at 30-40°C and 800-1200 rpm for 60-90 minutes; Premix component B and mature it for 24 to 48 hours; When in use, the A component and the B component are mixed in a weight ratio of 5:1 and then sprayed or rolled to form a coating with a dry film thickness of 80 to 150 μm, thereby obtaining a highly water-resistant waterborne polyurethane marine coating.

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