Marine antifouling polyurethane coating material based on zwitterionic resin and synthesis method thereof

Abstract

The invention belongs to the technical field of marine antifouling materials, and particularly relates to a marine antifouling polyurethane coating material based on zwitterionic resin and a synthesis method thereof.The synthesis method comprises the steps that the molar ratio R1 of isocyanato to hydroxyl is controlled to be 1.6-2.0, and a polyurethane prepolymer is synthesized through macromolecular polyol and aliphatic or alicyclic diisocyanate; the preparation method comprises the following steps: synthesizing zwitterionic polyol from N-methyldiethanolamine, triethanolamine, acid anhydride, sultone, a bisphenol compound and a polar solvent, then adding a prepolymer diluted by the polar solvent, and controlling the molar ratio of isocyanato hydroxyl to 1.6-2.0 to carry out chain extension so as to introduce a large amount of zwitterionic ions, thereby obtaining the product. The tensile shear strength of the coating is larger than 3.0 MPa, the 180-degree peel strength is larger than 10 N / cm, and the marine coupon antifouling performance score within 24 months is larger than 95. The zwitterionic polyol synthesis route raw materials are low in price and easy to obtain, the zwitterionic polyol is introduced into a polyurethane main chain, no organic or heavy metal ion antifouling agent needs to be added, the main chain contains hydrophilic and hydrophobic soft segment chains, the adhesion of an antifouling coating can be kept in dry and wet environments, and the anti-microbial effect of zwitterionic can be exerted; the marine antifouling paint has remarkable environmental protection and intrinsic long-acting marine antifouling characteristics.

Description

Technical Field

[0001] The present invention belongs to the technical field of marine antifouling materials, and particularly relates to an amphoteric ion resin-based marine antifouling polyurethane coating material and a synthesis method thereof. Background Art

[0002] Marine biofouling, that is, the undesirable accumulation of marine microorganisms, plants, and animals on the underwater surfaces of equipment such as ship hulls, marine engineering facilities, submersibles, and seawater aquaculture tanks, has many adverse effects on the marine industry and maritime activities. The excessive reproduction of fouling organisms on marine ships will increase the bottom weight and roughness of the ship, accelerate surface aging, damage facilities, cause safety problems, and at the same time lead to an increase in fuel consumption and maintenance costs. At present, applying antifouling coatings is the most effective strategy in terms of operation and economy, and it is also the most widely used method in marine antifouling technology.

[0003] Studies have shown that self-polishing copolymer coatings containing tributyltin (TBT) are highly effective in preventing the settlement and growth of marine organisms and were once regarded as the best solution. However, given the persistent toxicity of these coatings to non-target organisms, their use has been globally prohibited since 2003. After the ban, coatings containing alternative antifouling agents have played a key role in reducing the diversity of marine fouling. The most commonly used antifouling agents are compounds containing copper, zinc and other ions, as well as the organic compound 4,5-dichloro-N-octyl-4-isothiazolin-3-one (DCOIT). In 1991, zinc pyrithione (ZPT) was introduced into the field of ship antifouling as a substitute for TBT. The antifouling agent copper pyrithione (CPT) is a compound related to ZPT, which is characterized by easy photolysis and can be rapidly degraded into less toxic by-products. When CPT comes into contact with water, it will release copper ions (Cu2+), which can kill marine fouling organisms. When these ions diffuse from the surface, they are mainly neutralized through interactions with organic and inorganic ligands, thereby reducing the toxic effects and playing an antifouling role.

[0004] Strategies for introducing antifouling agents can achieve anti-marine biofouling growth, but there are still two problems: 1) For exogenous metal ion compounds or organic substances, it is difficult to regulate the release rate, and there is an effective period, so long-term antifouling cannot be achieved; 2) The release of heavy metal ions is still destructive to the marine environment. Some studies have shown that certain organic zwitterions have typical microbicidal properties. Introducing them into polyurethane can achieve intrinsic marine antifouling without exogenous addition of antifouling agents. However, conventional organic zwitterions are usually introduced into the polyurethane main chain in the form of small molecule chain extenders, with relatively low content and distributed in the hard segment phase region, and the effect of preventing marine algae attachment is inhibited. Therefore, how to explore new ways to increase the content of zwitterions through molecular design, taking into account the hydrophilic-hydrophobic properties in wet and dry seawater environments, to achieve the purpose of environmental protection, intrinsic long-term antifouling, and at the same time maintain a high level of adhesion ability is challenging and of industrial application value. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a marine antifouling polyurethane coating material based on zwitterionic resin and its synthesis method.

[0006] To achieve the above purpose, the technical solutions adopted by the present invention are as follows:

[0007] A marine antifouling polyurethane coating material based on zwitterionic resin is synthesized from N-methyldiethanolamine, triethanolamine, acid anhydride, sulfonic acid lactone, bisphenol compound, macromolecular polyol, and aliphatic or cycloaliphatic diisocyanate. The synthesis steps are mainly divided into three steps. The first step is to synthesize zwitterionic polyol through N-methyldiethanolamine, triethanolamine, acid anhydride, sulfonic acid lactone, and bisphenol compound. The second step is to synthesize polyurethane prepolymer through macromolecular polyol and aliphatic or cycloaliphatic diisocyanate. The third step is to carry out chain extension through zwitterionic polyol and polyurethane prepolymer to synthesize a polymer with isocyanate groups, that is, a marine antifouling polyurethane coating material based on zwitterionic resin.

[0008] Preferably, the synthesis method of the zwitterionic polyol comprises the following steps: (1) A bisphenol compound and an acid anhydride are introduced into a polar organic solvent (THF, cyclohexanone, DMF, acetonitrile, DMAc, DMSO or NMP), and the molar ratio of phenolic hydroxyl group to acid anhydride group is controlled to be 1:(1.02 - 1.05), and the temperature is raised to 60 - 100 °C for reaction for 4 - 12 hours to obtain a carboxyl-terminated product 1; (2) N-methyldiethanolamine / triethanolamine and a dehydrating agent dicyclohexylcarbodiimide are introduced, and the molar ratio of carboxyl group to hydroxyl group to dehydrating agent is controlled to be 1:(2.02 - 2.05):1.05, and the reaction is stirred at room temperature for 4 - 12 hours to remove by-products to obtain a hydroxyl-terminated product 2; (3) A sulfonic acid lactone is introduced, and the molar ratio of the total sum of tertiary amine groups of N-methyldiethanolamine + triethanolamine to sulfonic acid lactone is controlled to be 1:(1.02 - 1.05), and the temperature is controlled at 40 - 80 °C for reaction for 6 - 24 hours to obtain a zwitterionic polyol product 3.

[0009] Preferably, the bisphenol compound is one or a mixture of bisphenol A and bisphenol F.

[0010] Preferably, the acid anhydride is one or a mixture of methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, succinic anhydride, and maleic anhydride.

[0011] Preferably, the sulfonic acid lactone is one or a mixture of 1,3-propane sultone, allyl-1,3-sulfonic acid lactone, and 1,4-butane sultone.

[0012] Preferably, the synthesis method of the polyurethane prepolymer comprises the following steps: A macromolecular polyol is added, the temperature is raised to 100 - 110 °C for vacuum dehydration for 1 - 4 hours, the temperature is lowered to 70 - 90 °C, nitrogen is introduced, and then an aliphatic or cycloaliphatic diisocyanate and a catalyst are added, and the molar ratio of hydroxyl group to isocyanate group to catalyst is controlled to be 1:(1.6 - 2.0):0.0001, and the molar ratio value R1 of hydroxyl group to isocyanate group is 1.6 - 2.0, and the reaction is stirred for 2 - 8 hours to obtain a polyurethane prepolymer.

[0013] Preferably, the macromolecular polyol is one or a mixture of polyethylene glycol, polytetramethylene ether glycol, and polypropylene oxide polyol, and the number average molecular weight is 400 - 1600 g / mol.

[0014] Preferably, the aliphatic or cycloaliphatic diisocyanate is one or a mixture of hexamethylene diisocyanate, lysine diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate, and the catalyst is one or a mixture of dibutyltin dilaurate, organic zinc, and organic bismuth catalysts.

[0015] The present invention also discloses a method for synthesizing the zwitterionic resin marine antifouling polyurethane coating material, which comprises the following steps: putting the zwitterionic polyol product 3, heating to 100-110°C for vacuum dehydration for 1-4 hours, cooling to 70-90°C, introducing nitrogen, then adding a polyurethane prepolymer and a polar organic solvent (THF, cyclohexanone, DMF, acetonitrile, DMAc, DMSO or NMP) for dilution, controlling the molar ratio of isocyanate group / hydroxyl group R2 to be 1.6-2.0, introducing nitrogen while controlling the temperature in the range of 70-90°C, and stirring and reacting for 2-12 hours to obtain the zwitterionic resin marine antifouling polyurethane coating material.

[0016] The beneficial effects of the present invention are as follows:

[0017] (1) The raw materials of the zwitterionic polyol synthesis route are cheap and easily available, and the synthesis process is simple.

[0018] (2) The sulfonium inner salt zwitterion has a significant killing effect on marine microorganisms. Introducing it into the polyurethane main chain, without adding any organic small molecule antifouling agent or heavy metal ion antifouling agent, the zwitterions are distributed in the soft segment chain. Compared with conventional chain extenders, a higher content of zwitterions can be introduced. The main chain contains hydrophilic soft segment chains, hydrophobic soft segment chains and hydrophobic bisphenol compounds. The reasonable regulation of hydrophilicity and hydrophobicity helps the antifouling coating maintain adhesion and exert the antimicrobial effect of zwitterions in dry and wet environments. After the coating film is cured and formed and immersed in seawater, its surface swells, and the zwitterions can fully contact with microorganisms in seawater to kill marine microorganisms to prevent microorganisms from secreting adhesive protein substances.

[0019] (3) The tensile shear strength of the coating synthesized by the present invention is greater than 3.0 MPa, the 180° peel strength is greater than 10 N / cm, and the antifouling performance score of the 24-month marine hanging sheet is greater than 95 points, having significant environmental protection and intrinsic long-term marine antifouling characteristics.

[0020] Specific implementation examples

[0021] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0022] The raw materials used in the experiments of the embodiments and comparative examples of the present invention are as follows, but are not limited to the following raw materials. The present invention only uses the following raw materials as specific examples to further specifically illustrate the effects of the zwitterionic resin marine antifouling polyurethane coating material described in the present invention.

[0023] Bisphenol compound: Bisphenol A, Shanghai Sinopec Mitsui Chemical Co., Ltd.

[0024] Anhydride: Methylhexahydrophthalic anhydride, Puyang Huicheng Electronic Materials Co., Ltd.

[0025] Polar organic solvent: cyclohexanone, Jinan Jiangtai Chemical Co., Ltd.

[0026] N-Methyldiethanolamine: Changzhou Mingshun Chemical Co., Ltd.

[0027] Dehydrating agent: dicyclohexylcarbodiimide (DCC), Shandong Rongsheng New Materials Co., Ltd.

[0028] Sulfonic acid lactone: 1,3-propane sultone, Tiancheng Chemical (Jiangsu) Co., Ltd.

[0029] Macromolecular polyol: polyethylene glycol, number average molecular weight 1000 g / mol, Jiangsu Haian Petrochemical Factory.

[0030] Aliphatic or alicyclic diisocyanate: dicyclohexylmethane diisocyanate (HMDI), Yantai Wanhua.

[0031] Catalyst: dibutyltin dilaurate, Guangzhou Yourun Synthetic Materials Co., Ltd.

[0032] Examples 1 to 6 and Comparative Examples 1 to 4 are set in the present invention, and the molar feeding formula of the synthesis materials is shown in Table 1:

[0033] Table 1

[0034]

[0035] Examples 1 to 6 and Comparative Examples 1 to 4 are synthesized according to the following process:

[0036] (1) Bisphenol A and methylhexahydrophthalic anhydride are put into the polar organic solvent cyclohexanone, and the molar ratio of phenolic hydroxyl group to acid anhydride group is controlled to be 1:1.04. The temperature is raised to 80 °C and reacted for 6 hours to obtain the carboxyl-terminated product 1; N-methyldiethanolamine and the dehydrating agent dicyclohexylcarbodiimide are added, and the molar ratio of carboxyl group to hydroxyl group to dehydrating agent is controlled to be 1:2.04:1.05. Stir and react at room temperature for 6 hours to remove by-products and obtain the hydroxyl-terminated product 2; 1,3-propane sultone is added, and the molar ratio of the total tertiary amine groups of N-methyldiethanolamine to sulfonic acid lactone is controlled to be 1:1.04. The temperature is controlled at 60 °C and reacted for 12 hours to obtain the zwitterionic polyol product 3;

[0037] (2) Polyethylene glycol 1000 is added, the temperature is raised to 105 °C and vacuum dehydrated for 2 hours, then cooled to 80 °C and nitrogen is introduced. Then dicyclohexylmethane diisocyanate (HMDI) and the catalyst dibutyltin dilaurate are added, and the molar ratio of hydroxyl group to isocyanate group to catalyst is controlled to be 1:(1.6 - 2.0):0.0001, and the molar ratio value R1 of hydroxyl group to isocyanate group is 1.6 - 2.0. Stir and react for 6 hours to obtain the polyurethane prepolymer;

[0038] (3) Introduce the zwitterionic polyol product 3, heat up to 105 °C for vacuum dehydration for 2 hours, cool down to 80 °C, introduce nitrogen, then add the polyurethane prepolymer and the polar organic solvent cyclohexanone for dilution, control the molar ratio of isocyanate group to hydroxyl group R2 to be 1.5 - 2.2, control the temperature at 80 °C, introduce nitrogen, and stir and react for 6 hours to obtain the zwitterionic resin marine antifouling polyurethane coating material.

[0039] The materials prepared in the examples and comparative examples of the present invention are subjected to the following performance tests to evaluate their marine antifouling capabilities.

[0040] (1) Test for anti-algae adhesion ability. Make the materials of the examples and comparative examples into thin slices, immerse them in a constant temperature incubator at 23 °C containing Navicula and Nitzschia closterium f. minutissima, perform 12-hour light and 12-hour dark treatment every day, take out the samples after 3 days, gently rinse them with seawater, and then observe and count the algae density (number / mm 2 ).

[0041] (2) Marine environment antifouling evaluation. Refer to the method specified in GB / T 5370-2007 "Test Method for Submerged Exposure of Antifouling Paint Panels in Shallow Sea" for testing and determination. Coat the glue solutions of the examples and comparative examples on PVC plates, after full curing, conduct a long-term actual marine panel experiment in the Qingdao sea area for 24 months.

[0042] (3) Bonding performance. Coat the glue solutions of the examples and comparative examples on the steel plate substrate, and test their tensile shear strength and 180° peel strength.

[0043] The performance evaluation results of Examples 1 - 6 and Comparative Examples 1 - 4 of the present invention are shown in Table 2:

[0044] Table 2

[0045]

[0046]

[0047] It can be seen from Examples 1 - 6 and Comparative Examples 1 - 4 that introducing zwitterions endows the coating with excellent anti-algae adhesion and the ability to prevent the attachment and growth of other organisms. If zwitterions are not introduced into the main chain, there is no marine antifouling ability after 24 months of actual immersion in the open sea. By adjusting the R1 and R2 values, the contents of zwitterions and terminal isocyanate groups change. A higher content of zwitterions results in a lower density of attached algae, and the corresponding antifouling performance score is relatively higher. A higher content of isocyanate groups helps to improve the shear strength and peel strength. Thus, it can be seen that the introduction amounts of zwitterions and isocyanate groups should be within a reasonable range to achieve the long-term bonding of the coating and prevent the attachment and growth of marine organisms.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A zwitterionic resin-based marine antifouling polyurethane coating material, characterized in that, It is synthesized from N-methyldiethanolamine, triethanolamine, acid anhydride, sulfonic acid lactone, bisphenol compound, macromolecular polyol, aliphatic or alicyclic diisocyanate. The synthesis steps are mainly divided into three steps. The first step is to synthesize zwitterionic polyol from N-methyldiethanolamine, triethanolamine, acid anhydride, sulfonic acid lactone, and bisphenol compound. The second step is to synthesize polyurethane prepolymer from macromolecular polyol, aliphatic or alicyclic diisocyanate. The third step is to carry out chain extension between zwitterionic polyol and polyurethane prepolymer to synthesize a polymer with isocyanate groups, that is, the zwitterionic resin marine antifouling polyurethane coating material.

2. The zwitterionic resin-based marine antifouling polyurethane coating material according to claim 1, wherein The synthesis method of the zwitterionic polyol includes the following steps: (1) Put the bisphenol compound and acid anhydride into a polar organic solvent, control the molar ratio of phenolic hydroxyl group / acid anhydride group to be 1:(1.02 - 1.05), heat up to 60 - 100 °C and react for 4 - 12 hours to obtain the carboxyl-terminated product 1; (2) Put in N-methyldiethanolamine, triethanolamine and the dehydrating agent dicyclohexylcarbodiimide, control the molar ratio of carboxyl group / hydroxyl group / dehydrating agent to be 1:(2.02 - 2.05):1.05, stir and react at room temperature for 4 - 12 hours, remove the by-products to obtain the hydroxyl-terminated product 2; (3) Put in sulfonic acid lactone, control the molar ratio of the total tertiary amine groups of N-methyldiethanolamine + triethanolamine / sulfonic acid lactone to be 1:(1.02 - 1.05), control the temperature at 40 - 80 °C and react for 6 - 24 hours to obtain the zwitterionic polyol product 3.

3. The zwitterionic resin-based marine antifouling polyurethane coating material according to claim 2, characterized in that, The bisphenol compound is one or a mixture of bisphenol A and bisphenol F. The acid anhydride is one or a mixture of methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, succinic anhydride, and maleic anhydride. The polar organic solvent is THF, cyclohexanone, DMF, acetonitrile, DMAc, DMSO or NMP. The sulfonic acid lactone is one or a mixture of 1,3-propane sultone, allyl-1,3-sulfonic acid lactone, and 1,4-butane sultone.

4. The zwitterionic resin-based marine antifouling polyurethane coating material according to claim 3, wherein The synthesis method of the polyurethane prepolymer includes the following steps: Add macromolecular polyol, heat up to 100 - 110 °C and carry out vacuum dehydration for 1 - 4 hours, cool down to 70 - 90 °C and introduce nitrogen, then add aliphatic or alicyclic diisocyanate and catalyst, control the molar ratio of hydroxyl group / isocyanate group / catalyst to be 1:(1.6 - 2.0):0.0001, and the molar ratio value R1 of hydroxyl group / isocyanate group is 1.6 - 2.0, stir and react for 2 - 8 hours to obtain the polyurethane prepolymer.

5. The zwitterionic resin-based marine antifouling polyurethane coating material according to claim 4, wherein The macromolecular polyol is one or a mixture of polyethylene glycol, polytetramethylene ether glycol, and polypropylene oxide ether glycol, with a number average molecular weight of 400 - 1600 g / mol. The aliphatic or alicyclic diisocyanate is one or a mixture of hexamethylene diisocyanate, lysine diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate. The catalyst is one or a mixture of dibutyltin dilaurate, organic zinc, and organic bismuth catalysts.

6. A synthesis method of a zwitterionic resin-based marine antifouling polyurethane coating material as described in claim 5, characterized in that, It includes the following steps: put in the zwitterionic polyol product 3, heat up to 100-110 °C for vacuum dehydration for 1-4 hours, cool down to 70-90 °C, introduce nitrogen, then add polyurethane prepolymer and polar organic solvent for dilution, control the molar ratio of isocyanate group / hydroxyl group R2 to be 1.6-2.0, introduce nitrogen while controlling the temperature within the range of 70-90 °C, stir and react for 2-12 hours to obtain the zwitterionic resin marine antifouling polyurethane coating material.

7. The synthesis method of the zwitterionic resin-based marine antifouling polyurethane coating material according to claim 6, characterized in that, The polar organic solvent is THF, cyclohexanone, DMF, acetonitrile, DMAc, DMSO or NMP.

8. The zwitterionic resin-based marine antifouling polyurethane coating material according to any one of claims 1 to 5, characterized in that, The tensile shear strength is greater than 3.0 MPa, the 180° peel strength is greater than 10 N / cm, and the marine panel antifouling performance score after 24 months is greater than 95 points.

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