Two-component main chain degradable and side chain hydrolyzable marine antifouling coating and preparation method thereof

Abstract

The application relates to a two-component main-chain degradable and side-chain hydrolytic marine antifouling paint and a preparation method thereof, and relates to the technical field of marine antifouling paint. The paint comprises A component and B component. The A component comprises the following components in parts by weight: main-chain degradable and side-chain hydrolytic marine antifouling resin 30-60 parts, silane coupling agent 0-2 parts, red cuprous oxide 0-30 parts, organic antifouling agent 0-20 parts, pigment and filler 2-40 parts, thixotropic agent 0-1 part, anti-sagging agent 0-3 parts, and solvent 0-5 parts. The B component is a curing agent containing isocyanate groups. The prepared antifouling resin has excellent main-chain degradability and side-chain hydrolysis performance. During use, the marine antifouling resin can continuously release acid substances which are abhorred by marine microorganisms. Even in a static state, the coating surface can be gradually renewed through main-chain degradation, so that the antifouling effect is well achieved.

Description

Technical Field

[0001] This invention relates to the field of marine antifouling materials technology, and in particular to a two-component main-chain degradation and side-chain hydrolysis type marine antifouling coating and its preparation method. Background Technology

[0002] Marine biofouling, also known as marine organism attachment, refers to the phenomenon of marine animals, plants, and microorganisms attaching to equipment operating in the ocean, posing a significant threat to the modern marine economy. Once marine organisms attach to or grow on the surface of a ship, they increase frictional resistance, reduce speed, increase fuel consumption, damage coatings, accelerate steel corrosion, severely affect the ship's service life, increase maintenance frequency and costs, disrupt normal operations, and cause substantial economic losses.

[0003] According to foreign statistics and analysis, marine biofouling can increase ship fuel consumption by more than 40%, amounting to approximately 7 million tons of additional fuel consumption globally each year, resulting in direct economic losses of nearly 10 billion US dollars. Therefore, if the problem of marine biofouling is not effectively addressed, it will seriously affect the implementation of national strategies and constrain the development of the marine economy. Currently, China uses a large amount of marine antifouling coatings annually, with the majority of the market monopolized by giants such as Jotun, Kansai, Hempel, China National Coatings International, AkzoNobel, and Nippon Paint Marine Coatings; especially in the high-tech, high-value-added high-end antifouling coating sector, China is even more unable to compete.

[0004] Silicone-based fouling-removing coatings and polyacrylate self-polishing coatings are currently the best-performing and most widely used marine antifouling coatings. However, their fouling-removing performance depends on high water flow, and their static antifouling effect is not ideal.

[0005] Patent CN112961594A discloses a hydrolyzable and controllable marine antifouling coating and its preparation method. The coating includes component A and component B. Component A comprises 10-30% hydrolyzable and controllable resin, 0-30% other resins, 0-40% cuprous oxide, 0-10% copper pyridine thionate, 2-40% pigments and fillers, 0.1-2% leveling agent, 0-3% thickener, 0-10% chain extender, and 10-40% solvent. Component B is a curing agent. In this scheme, the hydrolyzable and controllable resin is a polyglycolic acid copolymer polyol. However, the hydrolysis controllability of the hydrolyzable and controllable resin in this patent is relatively poor.

[0006] Patent CN114716654A discloses a self-polishing antifouling resin with main-chain degradation properties and its preparation method. The raw materials for preparing the resin include the following components by mass: 1-60 parts citric acid monomer; 1-80 parts polyglycolic acid polyol; 1-80 parts polyester or polyether polyol; 20-80 parts solvent; 1-30 parts zinc-containing monomer; and 1-10 parts monobasic acid. The antifouling resin prepared by this application exhibits excellent main-chain degradation and side-chain hydrolysis properties. During use, it continuously releases citric acid-like substances that are disliked by marine microorganisms, forming a dynamic surface with fouling resistance. Even in a static state, the coating surface can gradually renew itself through main-chain degradation, thus effectively performing its antifouling function. In this patent, polyglycolic acid polyol and polyester or polyether polyol are used as the main monomers, and their degradation performance still needs further improvement. Summary of the Invention

[0007] In view of the poor degradation performance of existing marine antifouling coatings, this invention provides a two-component main-chain degradable and side-chain hydrolyzable marine antifouling coating and its preparation method.

[0008] The antifouling coating of this invention has excellent main chain degradation and side chain hydrolysis properties, and can exhibit good antifouling effect under both dynamic and static conditions. At the same time, the operation method of this invention is simple, the cost is low, it is suitable for industrial production, and has broad application prospects.

[0009] The objective of this invention can be achieved through the following technical solutions:

[0010] This invention provides a two-component main-chain degradable and side-chain hydrolyzable marine antifouling coating, comprising component A and component B.

[0011] Component A contains the following components:

[0012]

[0013] Component B is a curing agent containing isocyanate groups;

[0014] The main-chain degradable and side-chain hydrolyzable marine antifouling resin has a solid content of 45%–50% and is prepared from the following substances:

[0015]

[0016] In one embodiment of the present invention, the citric acid monomer has the following structural formula:

[0017]

[0018] In one embodiment of the present invention, the aliphatic polyester polyol can be prepared by the following steps:

[0019] a) Under nitrogen protection, polyacids, polyols, caprolactones and catalysts are subjected to esterification and polycondensation reactions at 140-230°C, the top temperature of the fractionation column is controlled between 100-105°C, and most of the water by-product generated is removed by atmospheric pressure.

[0020] b) Vacuum is drawn and the vacuum degree is gradually increased to remove trace amounts of water and excess polyol compounds under reduced pressure until the acid value of the synthesized product is lower than 5 mg KOH / g, thus obtaining aliphatic polyester polyol; reaction time is 4–12 h.

[0021] Preferably, the reaction equation for the aliphatic polyester polyol is as follows:

[0022]

[0023] Where R1 and R2 represent alkyl groups with 2 or more carbon atoms, and m and n are integers.

[0024] In practice, numerous seawater degradation experiments have been conducted on common biodegradable materials. Taking PLA as an example, under industrial composting conditions (temperature 58±2℃, humidity 98%, and the presence of certain microorganisms), PLA samples lose about 70% of their weight in approximately 50 days and can be completely degraded within 3-6 months. However, whether PLA samples are placed in fresh water or ocean, no significant weight loss is observed after a year of immersion, and GPC testing shows no significant change in molecular weight. Other biodegradable materials such as PBAT and PBS, although degrading faster in seawater than PLA, still show a weight loss of only about 2% after a year of immersion, indicating very slow degradation. However, by copolymerizing to reduce the molecular weight and crystallinity of aliphatic polyesters, their degradation performance in the ocean can be significantly improved.

[0025] Furthermore, compared to the near non-degradability of compostable biodegradable materials such as PLA, PBAT, and PBS in the ocean, polycaprolactone structures can be slowly degraded in seawater. At the same time, polycaprolactone structures have good flexibility. This invention can adjust the flexibility of antifouling resin by adding an appropriate amount of polycaprolactone structure, so that the prepared marine antifouling coating has good adhesion.

[0026] In one embodiment of the present invention, the aliphatic polyester polyol has the following structure:

[0027]

[0028] For ease of expression, it can be abbreviated as follows:

[0029] HO——R——OH

[0030] In one embodiment of the present invention, in the method for preparing aliphatic polyester polyol, the polyacid compound is one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, and sebacic acid.

[0031] In one embodiment of the present invention, in the method for preparing aliphatic polyester polyol, the polyol compound is one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, neopentanediol, hexanediol, isohexanediol, polyethylene glycol, polypropylene glycol, trimethylolpropane, and pentaerythritol.

[0032] In one embodiment of the present invention, in the method for preparing aliphatic polyester polyol, the molar ratio of the polyol to the polyacid is (0.5-60):1, and the molecular weight of the aliphatic polyester polyol is 300-3000.

[0033] More preferably, in the method for preparing aliphatic polyester polyol, the molar ratio of the polyol to the polyacid is (1-30):1, and the molecular weight of the aliphatic polyester polyol is 500-2000.

[0034] In one embodiment of the present invention, in the method for preparing aliphatic polyester polyol, the catalyst includes one or more of the following: stannous octoate, stannous chloride, tetrabutyl titanate, zinc acetate, antimony acetate, antimony trioxide, and antimony glycolate; the amount used is 0.01 to 2 wt% of the total mass of all monomers.

[0035] Preferably, in the raw materials for preparing the main-chain degradable and side-chain hydrolyzable marine antifouling resin, the solvent is one or more of methyl acetate, ethyl acetate, butyl acetate, isopropanol, n-butanol, toluene, xylene, methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone.

[0036] In one embodiment of the present invention, the zinc-containing monomer is one or more of zinc oxide, zinc hydroxide, zinc carbonate, zinc acetate, and zinc chloride.

[0037] In one embodiment of the present invention, the monocarboxylic acid includes one or more of formic acid, acetic acid, propionic acid, acrylic acid, methacrylic acid, glycolic acid, lactic acid, and lauric acid.

[0038] Preferably, the main-chain degradable and side-chain hydrolyzable marine antifouling resin can be prepared by the following steps:

[0039] a) Under nitrogen protection, citric acid, aliphatic polyester polyol and catalyst are esterified and polycondensed at a certain ratio between 140 and 230°C. The top temperature of the fractionation tower is controlled between 100 and 105°C. Most of the water by-product generated is removed by atmospheric pressure.

[0040] b) Evacuate the vacuum and gradually increase the vacuum level. Continue the reaction for 80-150 minutes under a pressure of <100Pa. After cooling, add solvent to obtain a marine antifouling resin prepolymer solution with main chain degradation and side chain hydrolysis.

[0041] c) Add an appropriate amount of zinc-containing monomer to a marine antifouling resin prepolymer solution with main-chain degradation and side-chain hydrolysis, react at 30-100℃ for 0.5-2 hours, then add a monobasic acid and continue the reaction for 0.5-2 hours to obtain a transparent resin solution. Then, purge with nitrogen to continue the reaction and evaporate excess water to obtain a marine antifouling resin with main-chain degradation and side-chain hydrolysis.

[0042] The structure of the main-chain degradation and side-chain hydrolysis type marine antifouling resin is shown below:

[0043]

[0044] Where R' represents alkyl groups, alkoxy groups, and vinyl groups with more than 1 carbon atom, and a, b, and c are integers.

[0045] The main chain of the marine antifouling resin, which is characterized by main chain degradation and side chain hydrolysis, is based on the degradation performance of aliphatic polyester polyol structure in seawater, thereby effectively coordinating the degradation properties of the coating. The antifouling coating prepared by this invention has excellent main chain degradation and side chain hydrolysis performance. During use, it can also continuously release acidic substances that are disliked by marine microorganisms, forming a dynamic surface. Under both dynamic and static conditions, the coating surface can be gradually renewed through main chain degradation, exhibiting a good antifouling effect.

[0046] In one embodiment of the present invention, in the preparation process of the main chain degradation and side chain hydrolysis type marine antifouling resin, the catalyst in step a) includes one or more of the following: stannous octoate, stannous chloride, tetrabutyl titanate, zinc acetate, antimony acetate, antimony trioxide, and antimony glycolate; the amount used is 0.01 to 2 wt% of the total mass of all monomers.

[0047] In one embodiment of the present invention, in the preparation process of the main chain degradation and side chain hydrolysis type marine antifouling resin, the molar ratio of the aliphatic polyester polyol to citric acid is 0.8 to 1.5:1; the molar ratio of the zinc-containing monomer to citric acid is 0.5 to 1.5:1; and the molar ratio of the zinc-containing monomer to the monocarboxylic acid is 1 to 10:1.

[0048] More preferably, in the preparation process of the main chain degradation and side chain hydrolysis type marine antifouling resin, the molar ratio of the aliphatic polyester polyol to citric acid is 0.9 to 1.1:1; the molar ratio of the zinc-containing monomer to citric acid is 0.8 to 1:1; and the molar ratio of the zinc-containing monomer to the monocarboxylic acid is 1 to 1.5:1.

[0049] In fact, citric acid is a tricarboxylic acid compound, but due to steric hindrance, the two terminal carboxyl groups will preferentially participate in the reaction. By controlling the molar ratio of aliphatic polyester polyol to citric acid, the main chain of the antifouling resin with controllable degradation rate can be guaranteed to be linear, reducing cross-linking.

[0050] Furthermore, the monocarboxylic acid can consume unreacted zinc monomers to form a zinc carboxylate structure, which can undergo ion exchange with sodium ions in seawater, giving the coating side-chain hydrolysis properties.

[0051] In one embodiment of the present invention, the silane coupling agent is an aminosilane coupling agent, specifically including one or more of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0052] In one embodiment of the present invention, the organic antifouling agent includes one or more of copper pyrithione, zinc pyrithione, zineb, (4,5-dichloro-N-octyl-4-isothiazolin-3-one)isothiazolinone derivative (DCOIT), and bromopyrrolidone.

[0053] In one embodiment of the present invention, the pigments and fillers include one or more of zinc oxide, talc, barium sulfate, diatomaceous earth, mica powder, titanium dioxide, and iron oxide red.

[0054] Pigments and fillers are important auxiliary materials in the preparation of marine antifouling coatings. They can give the coatings different colors and gloss levels, while effectively improving the physical properties of antifouling coatings and reducing their cost.

[0055] In one embodiment of the present invention, the thixotropic agent includes one or more of organobentonite, fumed silica, etc.

[0056] Adding thixotropic agents can increase the viscosity of marine antifouling coatings, reduce stratification during storage, and improve the storage stability of the coatings.

[0057] In one embodiment of the present invention, the anti-sagging agent includes one or more of polyamide wax, vegetable oleic acid, and polyurea.

[0058] In one embodiment of the present invention, the curing agent is one or more of the following: toluene diisocyanate and trimethylolpropane adduct (TDI-TMP), hexamethylene diisocyanate trimer (HDI trimer), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), and toluene diisocyanate dimer (TDI dimer); the mass ratio of component A to component B is 1 to 100:1.

[0059] More preferably, a two-component main-chain degradable and side-chain hydrolyzable marine antifouling coating, wherein the curing agent is one or more of the following: toluene diisocyanate and trimethylolpropane adduct (TDI-TMP), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and toluene diisocyanate dimer (TDI dimer); wherein the mass ratio of component A to component B is 10 to 50:1.

[0060] Adding an appropriate amount of curing agent can further crosslink with the hydroxyl groups in the main chain degraded and side chain hydrolyzed antifouling resin and the amino groups in the aminosilane coupling agent, thereby increasing the adhesion and hardness of the coating and improving its physical properties.

[0061] This invention also provides a method for preparing a two-component main-chain degradation and side-chain hydrolysis type marine antifouling coating, comprising the following steps:

[0062] (1) According to the ratio, first place the main chain degradation and side chain hydrolysis type antifouling resin solution in a disperser, add silane coupling agent and thixotropic agent at a speed of 500-1000 r / min, and continue stirring for 10-30 min;

[0063] (2) Add pigments, fillers and antifouling agents in the order from liquid to powder and from small to large specific gravity, and continue to disperse at a speed of 500 to 3000 r / min for 30 to 60 min until the fineness of the coating is below 80 μm;

[0064] (3) Add solvent according to viscosity and add anti-sagging agent, continue stirring at 500-3000 r / min for 20 min, filter and package to obtain main chain degradation and side chain hydrolysis type antifouling coating component A;

[0065] (4) Mix component A and component B directly before use.

[0066] Compared to existing acrylate-based tin-free self-polishing resins, which generally only contain hydrolyzable side groups and whose surface renewal depends on strong water flow, resulting in unsatisfactory static antifouling performance, the antifouling resin prepared in this invention exhibits excellent main-chain degradation and side-chain hydrolysis properties. During use, it continuously releases acidic substances that are disliked by marine microorganisms. Even in a static state, the coating surface can gradually renew itself through main-chain degradation, thus effectively performing its antifouling function. This invention is simple to operate, low in cost, applicable to various sea areas, and has broad application prospects.

[0067] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0068] (1) Controllable main chain degradation and side chain hydrolysis: This invention uses aliphatic polyester polyols with adjustable degradation rates in seawater as the main monomers. It is prepared by adjusting the crystallinity of aliphatic polyester polyols and the content of caprolactone, combined with citric acid monomers and zinc-containing monomers. Depending on the situation, we can prepare a series of self-polishing antifouling resins with different molecular weights and molecular structures to adapt to different applications. These resins have both main chain degradation and side chain hydrolysis effects, and exhibit good antifouling effects under both dynamic and static conditions.

[0069] (2) The developed main chain degradable and side chain hydrolyzable antifouling coating will continuously release acidic substances with antibacterial effect during the degradation process, so that the seawater on the coating surface and the normal seawater form a certain pH difference, making it difficult for marine fouling organisms to attach to its surface.

[0070] (3) The developed main chain degradation and side chain hydrolysis type antifouling coating has high strength and adhesion and excellent physical properties due to the introduction of citric acid monomer, aminosilane coupling agent and isocyanate curing agent.

[0071] (4) The developed main-chain degradable and side-chain hydrolyzable antifouling resin can be biodegraded in the ocean, reducing the generation of marine microplastics, and is an environmentally friendly antifouling resin.

[0072] (5) The developed main chain degradable and side chain hydrolyzable antifouling coating has abundant raw material sources, simple production process and affordable price, and is suitable for industrial production.

[0073] In summary, the main-chain degradable and side-chain hydrolyzable marine antifouling coating provided by this invention combines the effects of both main-chain degradation and side-chain hydrolysis, exhibiting good antifouling performance under both dynamic and static conditions. More importantly, this invention is simple to operate, low in cost, and suitable for industrial production. Attached Figure Description

[0074] Figure 1 The results of the shallow sea immersion experiment are shown. The coatings labeled 1, 2, 3, 4, 5, 6, 7, and 8 are respectively the coatings of Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Comparative Example 1, and Comparative Example 2. Detailed Implementation

[0075] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described herein. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0076] In the following embodiments:

[0077] As a preferred embodiment, using a main-chain degradable and side-chain hydrolyzable antifouling resin as the film-forming resin, component A of the main-chain degradable and side-chain hydrolyzable marine antifouling coating can be prepared by the following method:

[0078] (1) According to the ratio, first place the main chain degradation and side chain hydrolysis type antifouling resin solution in a disperser, add silane coupling agent, thixotropic agent and other additives at a speed of 500-1000 r / min, and continue stirring for 10-30 min.

[0079] (2) Add pigments, fillers and antifouling agents in the order from liquid to powder and from small to large specific gravity, and continue to disperse at a speed of 500 to 3000 r / min for 30 to 60 min until the fineness of the coating is below 80 μm.

[0080] (3) Add solvent according to viscosity and add anti-sagging agent. Continue stirring at 500-3000 r / min for 20 min, filter and package to obtain component A of main chain degradation and side chain hydrolysis antifouling coating.

[0081] Component B is a commercially available product; it can be used directly after mixing when applying.

[0082] The method for determining the acid value is as follows: Weigh 1-3g of polymer polyol and place it in a three-necked flask. Add 20-30mL of toluene-ethanol (2:1) mixed solution, shake the flask to completely dissolve the sample, and heat if necessary. Add 1% phenolphthalein indicator dropwise, and titrate with 0.1mol / L standard KOH solution until a faint red color appears and does not fade within 30s as the endpoint. Perform a blank test using the same method.

[0083]

[0084] In the formula:

[0085] V 试验 —The volume of standard KOH solution consumed in the experiment, in mL;

[0086] V 空白 —The volume of standard KOH solution consumed in the blank, in mL;

[0087] C—Molar concentration of KOH standard solution, mol / L;

[0088] W—Sample mass, g;

[0089] 56.10 — Molar mass of potassium hydroxide, g / mol.

[0090] The present invention does not impose any special restrictions on the raw materials used above, and they can be commercially available.

[0091] To further illustrate the present invention, the present invention will be further described below with reference to specific embodiments.

[0092] Example 1:

[0093] Preparation of aliphatic polyester polyols:

[0094] Under nitrogen protection, 59 g (0.5 mol) succinic acid, 63.6 g (0.6 mol) diethylene glycol, 34.2 g (0.3 mol) caprolactone and 0.3 g zinc acetate were added to the reactor. The oil bath was heated to 175 °C, and the temperature at the top of the fractionation column was maintained at 100–105 °C for 4 h. Subsequently, a vacuum was drawn and the vacuum degree was gradually increased to remove trace amounts of water and excess diethylene glycol under reduced pressure, yielding 130 g of transparent viscous aliphatic polyester polyol.

[0095] Preparation of antifouling resin with main chain degradation and side chain hydrolysis properties

[0096] Under nitrogen protection, 27.3 g (0.13 mol) citric acid monohydrate, 130 g of the above-mentioned aliphatic polyester polyol, and 0.3 g of zinc acetate were added to the reactor. The oil bath temperature was raised to 190 °C, and the temperature at the top of the fractionation column was maintained at 100–105 °C for 2 h. Then, a vacuum was drawn and the vacuum degree was gradually increased to remove trace amounts of water and excess alcohol under reduced pressure, yielding 124 g of product. Subsequently, 90 g of butyl acetate and 60 g of methyl isobutyl ketone were added to dissolve the product, resulting in a solution of antifouling resin prepolymer with main chain degradation and side chain hydrolysis properties.

[0097] Add 8.1 g (0.1 mol) of zinc oxide to the above solution and react at 80 °C for 30 min. Finally, add 5.8 g (0.08 mol) of acrylic acid and continue the reaction for 30 min to obtain a pale yellow transparent resin solution. Then, purge with nitrogen to continue the reaction and evaporate excess water to obtain a main chain degradation and side chain hydrolysis type antifouling resin solution with a solid content of 46%.

[0098] Prepare marine antifouling coating component A (containing cuprous oxide) according to the following weight ratio:

[0099] The product includes: 42g of the above-mentioned main chain degradation and side chain hydrolysis antifouling resin solution, 1g of silane coupling agent γ-aminopropyltriethoxysilane, 20g of cuprous oxide, 3g of organic antifouling agent copper pyridine thione, 29g of pigments and fillers (including 5g of zinc oxide, 10g of talc, 10g of barium sulfate and 4g of iron oxide red), 1g of organic bentonite, 1g of polyamide wax anti-sagging agent, and 3g of xylene solvent.

[0100] The curing agent for component B is an adduct of toluene diisocyanate and trimethylolpropane (TDI-TMP), and its amount is 6% of that of component A.

[0101] Example 2:

[0102] The main chain degradation and side chain hydrolysis type antifouling resin solution is the same as in Example 1;

[0103] Prepare marine antifouling coating component A (without cuprous oxide) according to the following weight ratio:

[0104] Includes: 42g of the above-mentioned main chain degradation and side chain hydrolysis antifouling resin solution, 1g of silane coupling agent γ-aminopropyltriethoxysilane, 10g of organic antifouling agent (including 3g of bromopyrrolidone, 3g of copper pyridinethione and 4g of DCOIT), 40g of pigments and fillers (including 5g of zinc oxide, 15g of talc, 15g of barium sulfate and 5g of iron oxide red), 1g of organic bentonite, 1g of polyamide wax anti-sagging agent, and 5g of xylene solvent.

[0105] The curing agent for component B is toluene diisocyanate (TDI), and its dosage is 2% of that of component A.

[0106] Example 3:

[0107] Preparation of aliphatic polyester polyols:

[0108] Under nitrogen protection, 41.6 g (0.4 mol) of malonic acid, 23.6 g (0.2 mol) of succinic acid, 72.8 g (0.7 mol) of neopentyl glycol, 45.6 g (0.4 mol) of caprolactone, and 0.2 g of stannous octoate were added to the reactor. The oil bath was heated to 185 °C, and the temperature at the top of the fractionation column was maintained at 100–105 °C for 3 h. Subsequently, a vacuum was drawn and the vacuum degree was gradually increased to remove trace amounts of water and excess neopentyl glycol under reduced pressure, yielding 145 g of viscous aliphatic polyester polyol.

[0109] Preparation of antifouling resin with main chain degradation and side chain hydrolysis properties

[0110] Under nitrogen protection, 31.5 g (0.15 mol) citric acid monohydrate, 145 g of the above-mentioned aliphatic polyester polyol, and 0.3 g stannous octoate were added to the reactor. The oil bath temperature was raised to 195 °C, and the temperature at the top of the fractionation column was maintained at 100–105 °C for 2 h. Subsequently, a vacuum was drawn and the vacuum degree was gradually increased to remove trace amounts of water and excess alcohol under reduced pressure, yielding 155 g of product. Then, 180 g of butyl acetate solvent was added to dissolve the product, resulting in a solution of antifouling resin prepolymer with main chain degradation and side chain hydrolysis properties.

[0111] Add 12g (0.12mol) of zinc hydroxide to the above solution and react at 80℃ for 30min. Finally, add 6g (0.1mol) of glacial acetic acid and continue the reaction for 30min to obtain a pale yellow transparent resin solution. Then, purge with nitrogen to continue the reaction and evaporate excess water to obtain a main chain degradation and side chain hydrolysis type antifouling resin solution with a solid content of 48%.

[0112] Prepare marine antifouling coating component A (containing cuprous oxide) according to the following weight ratio:

[0113] The product includes: 42g of the above-mentioned main chain degradation and side chain hydrolysis antifouling resin solution, 1g of silane coupling agent γ-aminopropyltriethoxysilane, 20g of cuprous oxide, 3g of organic antifouling agent copper pyridine thione, 29g of pigments and fillers (including 5g of zinc oxide, 10g of talc, 10g of barium sulfate and 4g of iron oxide red), 1g of organic bentonite, 1g of polyamide wax anti-sagging agent, and 3g of xylene solvent.

[0114] The curing agent for component B is an adduct of toluene diisocyanate and trimethylolpropane (TDI-TMP), and its amount is 8% of that of component A.

[0115] Example 4:

[0116] The main chain degradation and side chain hydrolysis type antifouling resin solution is the same as in Example 3;

[0117] Prepare marine antifouling coating component A (without cuprous oxide) according to the following weight ratio:

[0118] Includes: 42g of the above-mentioned main chain degradation and side chain hydrolysis antifouling resin solution, 1g of silane coupling agent γ-aminopropyltriethoxysilane, 10g of organic antifouling agent (including 3g of bromopyrrolidone, 3g of copper pyridinethione and 4g of DCOIT), 40g of pigments and fillers (including 5g of zinc oxide, 15g of talc, 15g of barium sulfate and 5g of iron oxide red), 1g of organic bentonite, 1g of polyamide wax anti-sagging agent, and 5g of xylene solvent.

[0119] The curing agent for component B is toluene diisocyanate (TDI), and its dosage is 3% of that of component A.

[0120] Example 5:

[0121] Preparation of aliphatic polyester polyols:

[0122] Under nitrogen protection, 47.2 g (0.4 mol) succinic acid, 58.4 g (0.4 mol) adipic acid, 67 g (0.88 mol) 1,2-propanediol and 22.8 g (0.2 mol) caprolactone were added to the reactor. The oil bath was heated to 140 °C to remove moisture. Then, 0.2 g tetrabutyl titanate catalyst was added. Subsequently, the oil bath was heated to 200 °C, and the temperature at the top of the fractionation column was maintained at 100–105 °C for 5 h. Finally, a vacuum was drawn and the vacuum degree was gradually increased to remove trace amounts of water and excess 1,2-propanediol under reduced pressure, yielding 155 g of viscous aliphatic polyester polyol.

[0123] Preparation of antifouling resin with main chain degradation and side chain hydrolysis properties

[0124] Under nitrogen protection, 25.2 g (0.12 mol) citric acid monohydrate, 155 g of the above-mentioned aliphatic polyester polyol, and 0.3 g tetrabutyl titanate were added to the reactor. The oil bath temperature was raised to 200 °C, and the temperature at the top of the fractionation column was maintained at 100–105 °C for 2 h. Subsequently, a vacuum was drawn and the vacuum degree was gradually increased to remove trace amounts of water and excess alcohol under reduced pressure, yielding 164 g of product. Then, 100 g of butyl acetate and 80 g of ethyl acetate were added to dissolve the product, resulting in a solution of antifouling resin prepolymer with main chain degradation and side chain hydrolysis properties.

[0125] 7.3 g (0.09 mol) of zinc oxide was added to the above solution, and the reaction was carried out at 80 °C for 30 min. Finally, 12 g (0.06 mol) of lauric acid was added, and the reaction was continued for another 30 min to obtain a pale yellow transparent resin solution. Nitrogen gas was then introduced to continue the reaction, and excess water was evaporated to obtain a main chain degradation and side chain hydrolysis type antifouling resin solution with a solid content of 48%.

[0126] Prepare marine antifouling coating component A (containing cuprous oxide) according to the following weight ratio:

[0127] The product includes: 42g of the above-mentioned main chain degradation and side chain hydrolysis antifouling resin solution, 1g of silane coupling agent γ-aminopropyltriethoxysilane, 20g of cuprous oxide, 3g of organic antifouling agent copper pyridine thione, 29g of pigments and fillers (including 5g of zinc oxide, 10g of talc, 10g of barium sulfate and 4g of iron oxide red), 1g of organic bentonite, 1g of polyamide wax anti-sagging agent, and 3g of xylene solvent.

[0128] The curing agent for component B is an adduct of toluene diisocyanate and trimethylolpropane (TDI-TMP), and its amount is 8% of that of component A.

[0129] Example 6:

[0130] The main chain degradation and side chain hydrolysis type antifouling resin solution is the same as in Example 5;

[0131] Prepare marine antifouling coating component A (without cuprous oxide) according to the following weight ratio:

[0132] Includes: 42g of the above-mentioned main chain degradation and side chain hydrolysis antifouling resin solution, 1g of silane coupling agent γ-aminopropyltriethoxysilane, 10g of organic antifouling agent (including 3g of bromopyrrolidone, 3g of copper pyridinethione and 4g of DCOIT), 40g of pigments and fillers (including 5g of zinc oxide, 15g of talc, 15g of barium sulfate and 5g of iron oxide red), 1g of organic bentonite, 1g of polyamide wax anti-sagging agent, and 5g of xylene solvent.

[0133] The curing agent for component B is toluene diisocyanate (TDI), and its dosage is 3% of that of component A.

[0134] Comparative Example 1:

[0135] Preparation of polylactic acid polyols:

[0136] Under nitrogen protection, 102 g (1 mol) of lactic acid with a mass concentration of 88%, 6 g (0.08 mol) of 1,3-propanediol, and 0.2 g of stannous octoate were added to the reactor. The oil bath was heated to 185 °C, and the temperature at the top of the fractionation column was maintained at 100–105 °C for 5 h. Subsequently, a vacuum was drawn and the vacuum degree was gradually increased to remove trace amounts of water and excess 1,3-propanediol under reduced pressure, yielding 66 g of waxy polylactic acid polyol.

[0137] Preparation of antifouling resin with main chain degradation and side chain hydrolysis properties

[0138] Under nitrogen protection, 25.2 g (0.12 mol) citric acid monohydrate, 66 g of the above-mentioned polylactic acid polyol, and 0.3 g of stannous octoate were added to the reactor. The oil bath temperature was raised to 200 °C, and the temperature at the top of the fractionation column was maintained at 100–105 °C for 3 h. Subsequently, a vacuum was drawn and the vacuum degree was gradually increased to remove trace amounts of water and excess alcohol under reduced pressure, yielding 73 g of product. Then, 70 g of butyl acetate and 15 g of ethyl acetate were added as solvents to dissolve the product, resulting in a solution of antifouling resin prepolymer with main chain degradation and side chain hydrolysis properties.

[0139] 7.3 g (0.09 mol) of zinc oxide was added to the above solution, and the reaction was carried out at 80 °C for 30 min. Finally, 4.2 g (0.07 mol) of glacial acetic acid was added, and the reaction was continued for another 30 min to obtain a pale yellow transparent resin solution. Nitrogen gas was then introduced to continue the reaction, and excess water was evaporated to obtain a main chain degradation and side chain hydrolysis type antifouling resin solution with a solid content of 48%.

[0140] Prepare marine antifouling coating component A (containing cuprous oxide) according to the following weight ratio:

[0141] The product includes: 42g of the above-mentioned main chain degradation and side chain hydrolysis antifouling resin solution, 1g of silane coupling agent γ-aminopropyltriethoxysilane, 20g of cuprous oxide, 3g of organic antifouling agent copper pyridine thione, 29g of pigments and fillers (including 5g of zinc oxide, 10g of talc, 10g of barium sulfate and 4g of iron oxide red), 1g of organic bentonite, 1g of polyamide wax anti-sagging agent, and 3g of xylene solvent.

[0142] The curing agent for component B is an adduct of toluene diisocyanate and trimethylolpropane (TDI-TMP), and its amount is 8% of that of component A.

[0143] Comparative Example 2:

[0144] The main chain degradation and side chain hydrolysis type antifouling resin solution is the same as that in Comparative Example 1;

[0145] Prepare marine antifouling coating component A (without cuprous oxide) according to the following weight ratio:

[0146] Includes: 42g of the above-mentioned main chain degradation and side chain hydrolysis antifouling resin solution, 1g of silane coupling agent γ-aminopropyltriethoxysilane, 10g of organic antifouling agent (including 3g of bromopyrrolidone, 3g of copper pyridinethione and 4g of DCOIT), 40g of pigments and fillers (including 5g of zinc oxide, 15g of talc, 15g of barium sulfate and 5g of iron oxide red), 1g of organic bentonite, 1g of polyamide wax anti-sagging agent, and 5g of xylene solvent.

[0147] The curing agent for component B is toluene diisocyanate (TDI), and its dosage is 3% of that of component A.

[0148] Long-term, firm adhesion to the substrate surface is a prerequisite for the antifouling effect of marine antifouling coatings. Therefore, coating adhesion strength is one of the important indicators for evaluating the quality of marine antifouling coatings. Coating adhesion strength is determined using a tensile method.

[0149] Using MARK iron sheets coated with epoxy zinc-rich primer as substrates, the adhesion strength of eight marine antifouling coatings prepared in Examples 1-6 and Comparative Examples 1-2 was tested according to ASTM D 4541 standard. As shown in Table 1, the adhesion strength of the antifouling coatings prepared in Examples 1-6 and Comparative Examples 1-2 all exceeded 2 MPa, which fully meets the requirements for the use of marine antifouling coatings.

[0150] Table 1. Adhesion strength of antifouling coatings prepared in Examples 1-6 and Comparative Examples 1-2

[0151]

[0152]

[0153] Eight types of marine antifouling coatings prepared in Examples 1-6 and Comparative Examples 1-2 were subjected to shallow sea immersion tests according to the national standard GB / T5370-2007 "Antifouling Paint Sample Shallow Sea Immersion Test Method". The test location was the Luomen sea area of ​​Zhoushan City. The antifouling agents and additives used in Examples 1, 3, 5 and Comparative Example 1 were the same, and the antifouling agents and additives used in Examples 2, 4, 6 and Comparative Example 2 were the same. None of the coatings contained cuprous oxide. The test period was from July 22, 2022 to July 19, 2023, with a period of one year. The results are as follows: Figure 1 As shown, after one year of shallow sea immersion experiments, the surfaces of the samples in Examples 1-6 remained smooth with virtually no marine organisms adhering to them, demonstrating excellent antifouling performance. In contrast, in Comparative Examples 1-2, the coating degradation rate was slow due to the addition of only polylactic acid polyol structures with a slower degradation rate to the main chain, resulting in less than ideal antifouling effects. Furthermore, this invention features a simple operation method, low cost, and suitability for industrial production.

[0154] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A two-component, main-chain degradable, side-chain hydrolyzable marine antifouling coating, characterized in that, Includes component A and component B. Component A contains the following components: Main-chain degradation and side-chain hydrolysis type marine antifouling resin 30-60%, Silane coupling agent 0~2%, Cuprous oxide 0~30%, Organic antifouling agent 0~20%, Pigments and fillers 2-40%, Thixotropic agent 0~1%, Anti-sagging agent 0~3%, Solvent 0~5%; Component B is a curing agent containing isocyanate groups; The mass ratio of component A to component B is 1~100:1; The main-chain degradable and side-chain hydrolyzable marine antifouling resin has a solid content of 45%~50% and is prepared from the following substances: Citric acid monomer 1-60 parts, 1-80 parts of aliphatic polyester polyol Solvent 20-80 parts Contains 1-30 parts of zinc monomer; 1-10 parts of monocarboxylic acid; The preparation process of a main-chain degradation and side-chain hydrolysis type marine antifouling resin, wherein the molar ratio of the aliphatic polyester polyol to citric acid is 0.9~1.1:1; the molar ratio of the zinc-containing monomer to citric acid is 0.8~1:1; and the molar ratio of the zinc-containing monomer to the monocarboxylic acid is 1~1.5:

1. The structure of the main-chain degradation and side-chain hydrolysis type marine antifouling resin is shown below: Where R' represents an alkyl group, alkoxy group, or vinyl group with 1 or more carbon atoms, and a, b, and c are integers; During use, the antifouling coating can continuously release acidic substances that are disliked by marine microorganisms, forming a dynamic surface. Under both dynamic and static conditions, the coating surface is gradually renewed through main chain degradation, exhibiting an antifouling effect.

2. The two-component main-chain degradable and side-chain hydrolyzable marine antifouling coating according to claim 1, characterized in that, The structural formula of the citric acid monomer is as follows: 。 3. The two-component main-chain degradable and side-chain hydrolyzable marine antifouling coating according to claim 1, characterized in that, The aliphatic polyester polyol has the following structure: Where R1 and R2 represent alkyl groups with 2 or more carbon atoms, and m and n are integers.

4. The two-component main-chain degradable and side-chain hydrolyzable marine antifouling coating according to claim 3, characterized in that, The aliphatic polyester polyol is prepared by the following steps: a) Under nitrogen protection, polyacids, polyols, caprolactones and catalysts are subjected to esterification and polycondensation reactions at 140~230℃, the top temperature of the fractionation column is controlled between 100~105℃, and most of the water by-product generated is removed by atmospheric pressure. b) Vacuum is drawn and the vacuum degree is gradually increased to remove trace amounts of water and excess polyol compounds under reduced pressure until the acid value of the synthesized product is lower than 5 mg KOH / g, thus obtaining aliphatic polyester polyol; reaction time is 4~12 h. The polyacid is one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, and sebacic acid; The polyol is one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, neopentanediol, hexanediol, isohexanediol, polyethylene glycol, polypropylene glycol, trimethylolpropane, and pentaerythritol; The molar ratio of the polyol to the polyacid is (0.5~60):1, and the molecular weight of the aliphatic polyester polyol is 300~3000; The catalyst comprises one or more of stannous octoate, stannous chloride, tetrabutyl titanate, zinc acetate, antimony acetate, antimony trioxide, and antimony glycolate; the amount used is 0.01 to 2 wt% of the total mass of all monomers.

5. The two-component main-chain degradable and side-chain hydrolyzable marine antifouling coating according to claim 1, characterized in that, The solvent used to prepare a main-chain degradable and side-chain hydrolyzable marine antifouling resin is one or more of methyl acetate, ethyl acetate, butyl acetate, isopropanol, n-butanol, toluene, xylene, methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone. The zinc-containing monomer is one or more of zinc oxide, zinc hydroxide, zinc carbonate, zinc acetate, and zinc chloride; The monocarboxylic acid includes one or more of formic acid, acetic acid, propionic acid, acrylic acid, methacrylic acid, glycolic acid, lactic acid, and lauric acid.

6. The two-component main-chain degradable and side-chain hydrolyzable marine antifouling coating according to claim 1, characterized in that, The main-chain degradation and side-chain hydrolysis type marine antifouling resin is prepared through the following steps: a) Under nitrogen protection, citric acid, aliphatic polyester polyol and catalyst are esterified and polycondensed at a certain ratio between 140 and 230°C. The top temperature of the fractionation tower is controlled between 100 and 105°C. Most of the water by-product generated is removed by atmospheric pressure. b) Evacuate the vacuum and gradually increase the vacuum level. Continue the reaction for 80-150 minutes under a pressure of <100Pa. After cooling, add a solvent to dissolve the resin and obtain a marine antifouling resin prepolymer solution with main chain degradation and side chain hydrolysis. c) Add an appropriate amount of zinc-containing monomer to a marine antifouling resin prepolymer solution with main-chain degradation and side-chain hydrolysis, react at 30~100℃ for 0.5~2h, finally add a monobasic acid, and continue the reaction for 0.5~2h to obtain a transparent resin solution. Then, purge with nitrogen to continue the reaction and evaporate excess water to obtain a marine antifouling resin with main-chain degradation and side-chain hydrolysis. The catalyst described in step a) comprises one or more of stannous octoate, stannous chloride, tetrabutyl titanate, zinc acetate, antimony acetate, antimony trioxide or antimony glycolate, and is used in an amount of 0.01 to 2 wt% of the total mass of all monomers.

7. The two-component main-chain degradable and side-chain hydrolyzable marine antifouling coating according to claim 1, characterized in that, The silane coupling agent is an aminosilane coupling agent, specifically including one or more of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; The organic antifouling agent includes one or more of copper pyrithione, zinc pyrithione, zineb, (4,5-dichloro-N-octyl-4-isothiazolin-3-one)isothiazolinone derivatives and bromopyrrolidone. The pigments and fillers include one or more of zinc oxide, talc, barium sulfate, diatomaceous earth, mica powder, titanium dioxide, and iron oxide red. The thixotropic agent includes one or more of organobentonite and fumed silica; The anti-sagging agent includes one or more of polyamide wax, vegetable oleic acid, and polyurea.

8. The two-component main-chain degradable and side-chain hydrolyzable marine antifouling coating according to claim 1, characterized in that, The curing agent is one or more of the following: toluene diisocyanate and trimethylolpropane adduct, hexamethylene diisocyanate trimer, isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and toluene diisocyanate dimer.

9. A method for preparing a two-component main-chain degradable and side-chain hydrolyzable marine antifouling coating according to any one of claims 1-8, characterized in that, Includes the following steps: (1) According to the ratio, first place the main chain degradation and side chain hydrolysis type antifouling resin solution in a disperser, add silane coupling agent and thixotropic agent at a speed of 500-1000 r / min, and continue stirring for 10-30 min; (2) Add pigments, fillers and antifouling agents in the order from liquid to powder and from small to large specific gravity, and continue to disperse at a speed of 500~3000r / min for 30~60min until the fineness of the coating is below 80μm; (3) Add solvent according to viscosity and add anti-sagging agent, continue stirring at 500~3000r / min for 20min, filter and package to obtain main chain degradation and side chain hydrolysis type antifouling coating component A; (4) Mix component A and component B directly before use.

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