Modified polyurethane marine antifouling paint based on metal pyridine structure and preparation method thereof

Abstract

The invention relates to the technical field of marine antifouling materials, in particular to a modified polyurethane marine antifouling coating based on a metal pyridine structure and a preparation method. According to the modified polyurethane marine antifouling paint based on the metal pyridine structure, polyhydric alcohols and diisocyanate monomers with different molecular weights are subjected to condensation polymerization to obtain a polyurethane prepolymer; then reacting a diaminopyridine monomer or a dihydroxypyridine monomer with a metal ion compound to obtain a chain extender with a metal pyridine structure; finally, the marine antifouling paint is prepared through the reaction between the terminal amino or hydroxyl of the metal pyridine structure chain extender and the terminal isocyanate group of the polyurethane prepolymer, the metal pyridine structure is introduced into polyurethane, the mechanical performance of the marine antifouling paint is enhanced, the marine antifouling paint is endowed with the antibacterial effect through metal ion release, and the service life of the marine antifouling paint is prolonged. Adhesion and growth of marine fouling organisms can be effectively inhibited, and an efficient and durable solution is provided for development of a polyurethane marine antifouling coating.

Description

Technical Field

[0001] The present invention relates to the technical field of marine antifouling materials, and in particular to a metal pyridine-based structure-modified polyurethane marine antifouling coating and a preparation method thereof. Background Art

[0002] Marine biofouling refers to the phenomenon that marine organisms (such as algae, barnacles, shellfish, tube worms, etc.) attach to the surface of ships, offshore facilities or artificial structures. This natural process can cause many kinds of losses to human activities and the economy. Marine antifouling materials are a key means to deal with the problem of marine biofouling. Traditional technologies mainly rely on acrylate resins or silicone resins as matrix materials. Acrylate resin matrix is ​​widely used because of its characteristic of slowly releasing antifouling agents in seawater, but it has problems such as poor water resistance and insufficient mechanical properties, which makes the coating prone to uneven performance or falling off due to construction fluctuations or seawater erosion, requiring frequent maintenance and increasing costs. Silicone resin can reduce biological attachment by virtue of its low surface energy characteristics. For example, patent number CN119286398A discloses a silicone marine antifouling and anticorrosive coating. Its process synthesis conditions are simple, clean and environmentally friendly, and the ultraviolet light-induced cross-linking reaction is rapid and effective, but its mechanical strength is low and its adhesion to the substrate is poor, making it difficult to meet the dynamic wear requirements in long-term marine environments.

[0003] Polyurethane materials have been introduced into the field of marine protection due to their excellent physical and mechanical properties, chemical corrosion resistance, and good processing properties. However, they lack antifouling activity and are difficult to directly inhibit biofouling, limiting their application value. Therefore, polyurethane materials need to be modified to impart antifouling properties. Existing modification technologies include grafting antifouling functional groups (such as fluorine-containing, silicon-containing, or bioactive molecules) or introducing nanofillers (such as graphene-loaded nanocopper). For example, patent No. CN118496404A introduces hydroxyl groups to both ends of the polymer through a special catalyst, and simultaneously copolymerizes monomers containing antifouling chemical structures with structural monomers to obtain a hydroxyl / antifouling dual-functional marine antifouling resin. However, this method faces problems such as complex process and high cost. The grafting reaction requires multi-step synthesis or harsh conditions, and the dispersion uniformity of the nanofiller is difficult to control, which affects the stability of the coating performance.

[0004] In view of this, it is urgent to focus on the coordinated optimization of marine antifouling material systems, that is, to develop efficient, process-simplified and economical antifouling modification strategies while maintaining mechanical stability and adaptability to the marine environment, so as to balance the needs of long-term protection and large-scale application. Summary of the Invention

[0005] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a polyurethane marine antifouling coating based on a metal pyridine structure modification and a preparation method thereof.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a polyurethane marine antifouling coating based on a metal pyridine structure is composed of the following raw materials, including polyols of different molecular weights, diisocyanate monomers, chain extenders, N,N-dimethylformamide, and metal ion compounds, wherein the chain extenders include diaminopyridine monomers or dihydroxypyridine monomers and N,N-dimethylformamide.

[0007] Furthermore, the polyols of different molecular weights include, but are not limited to, one or more of polypropylene glycol, polytetramethylene glycol, polybutylene adipate glycol, and poly-ε-caprolactone glycol.

[0008] Furthermore, the diisocyanate monomer includes, but is not limited to, one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

[0009] Furthermore, the diaminopyridine monomer includes but is not limited to one or more of 2,6-diaminopyridine, 2,5-diaminopyridine, and 2,4-diaminopyridine; the dihydroxypyridine monomer includes but is not limited to one or more of 2,6-dihydroxypyridine, 3,4-dihydroxypyridine, and 3,5-dihydroxypyridine.

[0010] Furthermore, the metal ion compound includes but is not limited to one or more of copper chloride, copper sulfate, zinc chloride, and silver nitrate.

[0011] The preparation method of the polyurethane marine antifouling coating based on the metal pyridine structure modification is characterized in that the preparation method of the polyurethane marine antifouling coating based on the metal pyridine structure modification is as follows:

[0012] S1. Pretreatment: melt polyols of different molecular weights in an oven at 60-80°C, then take a certain amount of polyol into a three-necked flask, connect a vacuum pump, and heat in an oil bath at 115-125°C under vacuum conditions, and magnetically stir at 200-300 rpm for 2-3 hours to remove water; and dry the remaining reagents and instruments.

[0013] S2. Synthesis of a polyurethane prepolymer containing terminal isocyanate groups: a certain amount of the polyol and diisocyanate monomers after dehydration in step S1 are added to a three-necked flask, which is sealed and mechanically stirred at 200-300 rpm in an oil bath at 40-60° C. for 1-2 hours, then heated to 70-90° C. and mechanically stirred for 2-5 hours to obtain a polyurethane prepolymer containing terminal isocyanate groups;

[0014] S3. Synthesis of a metal pyridine structure chain extender containing an amino group or a hydroxyl group at the end: a certain amount of diaminopyridine monomer or dihydroxypyridine monomer is added to a certain amount of N,N-dimethylformamide at room temperature, and ultrasonically treated for 5 to 10 minutes to completely dissolve it. Then, a certain amount of a metal ion compound is added to the solution, and ultrasonically treated for 5 to 10 minutes to completely dissolve it, thereby obtaining a metal pyridine structure chain extender containing an amino group or a hydroxyl group at the end;

[0015] S4. Synthesis of a polyurethane marine antifouling coating modified by a metal pyridine structure: The polyurethane prepolymer containing an isocyanate group at the end obtained in step S2 and the metal pyridine chain extender containing an amino group or a hydroxyl group at the end obtained in step S3 are mixed in a certain proportion, stirred at room temperature for 5 to 10 minutes to ensure uniform mixing, and vacuum-evacuated until no bubbles are present to obtain a polyurethane marine antifouling coating modified by a metal pyridine structure.

[0016] Furthermore, the molar ratio of the diisocyanate monomer to the polyol is 2.1:1.

[0017] Furthermore, the molar ratio of the metal ion compound to the diaminopyridine monomer or the dihydroxypyridine monomer is 1:1 to 1:5.

[0018] Furthermore, the ratio of diaminopyridine monomer or dihydroxypyridine monomer to N,N-dimethylformamide is 0.17 g / mL.

[0019] Furthermore, the molar ratio of the polyurethane prepolymer containing an isocyanate group at the end to the metal pyridine structure chain extender containing an amino group or a hydroxyl group at the end is 1:1.

[0020] Compared with the existing technology, the technical solution of this application has the following beneficial effects:

[0021] 1. The present invention obtains a polyurethane prepolymer containing an isocyanate group at the end by a condensation reaction of polyols of different molecular weights and diisocyanate monomers; then obtains a metal pyridine structure chain extender containing an amino group or a hydroxyl group at the end by reacting a diaminopyridine monomer or a dihydroxypyridine monomer with a metal ion compound; and finally, a metal pyridine structure-modified polyurethane marine antifouling coating is prepared by reacting the terminal amino group or hydroxyl group of the metal pyridine structure chain extender with the terminal isocyanate group of the polyurethane prepolymer. The production process is simple, easy to operate, and suitable for industrial mass production.

[0022] 2. The system of this application contains a large number of carbamate bonds and urea bonds, which provide a large number of hydrogen bonds. The metal ions and pyridine rings form a coordination structure and provide coordination bonds, which together give the coating excellent mechanical properties. The tensile strength exceeds 33.7 MPa and the elongation at break is as high as 1019.1%.

[0023] 3. The metal pyridine structure-modified polyurethane marine antifouling coating prepared by the present invention has excellent long-term antibacterial and antifouling effects, with an antibacterial rate of not less than 93% and an antifouling period of more than 1 year. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the reaction of the pyridine-copper structure modified polyurethane marine antifouling coating in Example 1 of the present invention. DETAILED DESCRIPTION

[0025] The technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0026] Example 1

[0027] A method for preparing a pyridine-copper structure-modified polyurethane marine antifouling coating, comprising the following steps:

[0028] S1, pre-treatment: polytetrahydrofuran diol (molecular weight 2000) is melted in 80 ℃ of baking ovens, get a certain amount of polytetrahydrofuran diol (400~500g) in 1000mL three-necked flask, access vacuum pump, under vacuum condition (0.1MPa), 120 ℃ of oil bath heating, 200r / min magnetic agitation 2h dewater; All the other employed reagents and instrument are carried out drying treatment at 60 ℃ of baking ovens;

[0029] S2. Synthesis of a polyurethane prepolymer containing terminal isocyanate groups: 400 g of polytetrahydrofuran diol and 70.64 g of hexamethylene diisocyanate were added to a 1000 mL three-necked flask, which was sealed and mechanically stirred at 200 rpm in an oil bath at 50° C. for 1 h. The temperature was then raised to 80° C. and mechanically stirred for 4 h to obtain a polyurethane prepolymer containing terminal isocyanate groups. The prepolymer can be sealed and stably stored for one month.

[0030] S3. Synthesis of a pyridine-copper structure chain extender containing an amino group at the end: 1.70 g of 2,6-diaminopyridine was added to 10 mL of N,N-dimethylformamide at room temperature and sonicated for 5 minutes to completely dissolve it. Then, 0.52 g of anhydrous copper chloride was added to the solution and sonicated for 5 minutes to completely dissolve it, thereby obtaining a pyridine-copper structure chain extender containing an amino group at the end;

[0031] S4. Synthesis of a pyridine-copper structure-modified polyurethane coating: 36.40 g of a polyurethane prepolymer containing an isocyanate group at the end was mixed with the pyridine-copper structure chain extender containing an amino group at the end prepared in step S3, and the mixture was stirred at room temperature for 5 minutes to uniformly mix. The mixture was then vacuum-evacuated (-0.1 MPa) until no bubbles were present to obtain a pyridine-copper structure-modified polyurethane coating.

[0032] The obtained pyridine-copper structure modified polyurethane coating was tested for mechanical properties and antibacterial properties:

[0033] The tensile strength is 33.7MPa, the elongation at break is 1019.1%; the antibacterial rate is as high as 95.1%.

[0034] Example 2

[0035] A method for preparing a pyridine-zinc structure-modified polyurethane marine antifouling coating, comprising the following steps:

[0036] S1. Pretreatment: melt polypropylene glycol in an oven at 80°C, take a certain amount (400-500 g) of polypropylene glycol (molecular weight 2000) into a 1000 mL three-necked flask, connect a vacuum pump, and remove water under vacuum conditions (-0.1 MPa) in an oil bath at 120°C and magnetic stirring at 200 rpm for 2 h; dry the remaining reagents and instruments in an oven at 60°C;

[0037] S2. Synthesis of a polyurethane prepolymer containing terminal isocyanate groups: 400 g of polypropylene glycol and 105.11 g of diphenylmethane diisocyanate were added to a 1000 mL three-necked flask, which was sealed and mechanically stirred at 200 rpm in an oil bath at 50° C. for 1 h. The temperature was then raised to 80° C. and mechanically stirred for 4 h to obtain a polyurethane prepolymer containing terminal isocyanate groups. The prepolymer can be sealed and stored stably for one month.

[0038] S3. Synthesis of a pyridine-zinc structure chain extender containing a terminal hydroxyl group: 1.70 g of 2,6-diaminopyridine was added to 10 mL of N,N-dimethylformamide at room temperature and sonicated for 5 minutes to completely dissolve it. Then, 1.04 g of anhydrous zinc chloride was added to the solution and sonicated for 5 minutes to completely dissolve it, thereby obtaining a pyridine-zinc structure chain extender containing a terminal hydroxyl group;

[0039] S4. Synthesis of a pyridine-zinc structure-modified polyurethane coating: 38.26 g of a polyurethane prepolymer containing an isocyanate group at the end was mixed with the pyridine-zinc structure chain extender containing a hydroxyl group at the end prepared in step S3, and the mixture was stirred at room temperature for 5 minutes to uniformly mix. The mixture was then vacuum-evacuated (-0.1 MPa) until no bubbles were present to obtain a pyridine-zinc structure-modified polyurethane coating.

[0040] The obtained pyridine-zinc structure modified polyurethane coating was tested for mechanical properties and antibacterial properties:

[0041] The tensile strength is 35.9MPa, the elongation at break is 744.2%; the antibacterial rate is as high as 93%.

[0042] Example 3

[0043] A method for preparing a pyridine-silver structure-modified polyurethane marine antifouling coating, comprising the following steps:

[0044] S1. Pretreatment: melt poly-ε-caprolactone diol in an oven at 80°C, take a certain amount (400-500 g) of poly-ε-caprolactone diol (molecular weight 2000) into a 1000 mL three-necked flask, connect a vacuum pump, and remove water under vacuum conditions (-0.1 MPa) in an oil bath at 120°C and magnetic stirring at 200 r / min for 2 h; dry the remaining reagents and instruments in an oven at 60°C;

[0045] S2. Synthesis of a polyurethane prepolymer containing terminal isocyanate groups: 400 g of poly-ε-caprolactone diol and 93.36 g of isophorone diisocyanate were added to a 1000 mL three-necked flask, which was sealed and mechanically stirred at 200 rpm in an oil bath at 50° C. for 1 h. The temperature was then raised to 80° C. and mechanically stirred for 4 h to obtain a polyurethane prepolymer containing terminal isocyanate groups. The prepolymer can be sealed and stably stored for one month.

[0046] S3. Synthesis of a pyridine-silver structure chain extender containing a terminal hydroxyl group: 1.70 g of 3,5-diaminopyridine was added to 10 mL of N,N-dimethylformamide at room temperature and sonicated for 5 minutes to completely dissolve it. Then, 0.73 g of silver nitrate was added to the solution and sonicated for 5 minutes to completely dissolve it, thereby obtaining a pyridine-silver structure chain extender containing a terminal hydroxyl group;

[0047] S4. Synthesis of a pyridine-silver structure-modified polyurethane coating: 37.41 g of a polyurethane prepolymer containing an isocyanate group at the end was mixed with the pyridine-silver structure chain extender containing a hydroxyl group at the end prepared in step S3, and the mixture was stirred at room temperature for 5 minutes to uniformly mix. The mixture was then vacuum-evacuated (-0.1 MPa) until no bubbles were present to obtain a pyridine-silver structure-modified polyurethane coating.

[0048] The obtained pyridine-silver structure modified polyurethane coating was tested for mechanical properties and antibacterial properties:

[0049] The tensile strength is 34.8MPa, the elongation at break is 967.2%; the antibacterial rate is as high as 99.3%.

[0050] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0051] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. A polyurethane marine antifouling coating based on a metal pyridine structure modification, characterized by: The invention is composed of the following raw materials, including polyols with different molecular weights, diisocyanate monomers, chain extenders, N,N-dimethylformamide, and metal ion compounds. The chain extenders include diaminopyridine monomers or dihydroxypyridine monomers and N,N-dimethylformamide.

2. The metal pyridine structure-modified polyurethane marine antifouling coating according to claim 1, characterized in that: The polyols with different molecular weights include one or more of polypropylene glycol, polytetramethylene glycol, polybutylene adipate glycol, and polyε-caprolactone glycol.

3. The metal pyridine structure-modified polyurethane marine antifouling coating according to claim 1, characterized in that: The diisocyanate monomer includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

4. The metal pyridine structure-modified polyurethane marine antifouling coating according to claim 1, characterized in that: The diaminopyridine monomer includes one or more of 2,6-diaminopyridine, 2,5-diaminopyridine, and 2,4-diaminopyridine; the dihydroxypyridine monomer includes one or more of 2,6-dihydroxypyridine, 3,4-dihydroxypyridine, and 3,5-dihydroxypyridine.

5. The metal pyridine structure-modified polyurethane marine antifouling coating according to claim 1, characterized in that: The metal ion compound includes one or more of copper chloride, copper sulfate, zinc chloride, and silver nitrate.

6. A method for preparing a polyurethane marine antifouling coating based on a metal pyridine structure modification, characterized in that: The method for preparing the metal pyridine structure-modified polyurethane marine antifouling coating according to any one of claims 1 to 5 is as follows: S1. Pretreatment: melt polyols of different molecular weights in an oven at 60-80°C, then take a certain amount of polyol into a three-necked flask, connect a vacuum pump, and heat in an oil bath at 115-125°C under vacuum conditions, and magnetically stir at 200-300 rpm for 2-3 hours to remove water; and dry the remaining reagents and instruments. S2. Synthesis of a polyurethane prepolymer containing terminal isocyanate groups: a certain amount of the polyol and diisocyanate monomers after dehydration in step S1 are added to a three-necked flask, which is sealed and mechanically stirred at 200-300 rpm in an oil bath at 40-60° C. for 1-2 hours, then heated to 70-90° C. and mechanically stirred for 2-5 hours to obtain a polyurethane prepolymer containing terminal isocyanate groups; S3. Synthesis of a metal pyridine structure chain extender containing an amino group or a hydroxyl group at the end: a certain amount of diaminopyridine monomer or dihydroxypyridine monomer is added to a certain amount of N,N-dimethylformamide at room temperature, and ultrasonically treated for 5 to 10 minutes to completely dissolve it. Then, a certain amount of a metal ion compound is added to the solution, and ultrasonically treated for 5 to 10 minutes to completely dissolve it, thereby obtaining a metal pyridine structure chain extender containing an amino group or a hydroxyl group at the end; S4. Synthesis of a polyurethane marine antifouling coating modified by a metal pyridine structure: The polyurethane prepolymer containing an isocyanate group at the end obtained in step S2 and the metal pyridine chain extender containing an amino group or a hydroxyl group at the end obtained in step S3 are mixed in a certain proportion, stirred at room temperature for 5 to 10 minutes to ensure uniform mixing, and vacuum-evacuated until no bubbles are present to obtain a polyurethane marine antifouling coating modified by a metal pyridine structure.

7. The method for preparing a metal pyridine structure-modified polyurethane marine antifouling coating according to claim 6, characterized in that: The molar ratio of the diisocyanate monomer to the polyol is 2.1:

1.

8. The method for preparing a metal pyridine structure-modified polyurethane marine antifouling coating according to claim 6, characterized in that: The molar ratio of the metal ion compound to the diaminopyridine monomer or the dihydroxypyridine monomer is 1:1 to 1:

5.

9. The method for preparing a marine antifouling coating based on a metal pyridine structure-modified polyurethane according to claim 6, characterized in that: The ratio of diaminopyridine monomer or dihydroxypyridine monomer to N,N-dimethylformamide is 0.17 g / mL.

10. The method for preparing a marine antifouling coating based on a metal pyridine structure-modified polyurethane according to claim 6, characterized in that: The molar ratio of the polyurethane prepolymer containing an isocyanate group at the end to the metal pyridine structure chain extender containing an amino group or a hydroxyl group at the end is 1:1.

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