Polyurethane antifouling paint, preparation method thereof and polyurethane antifouling coating

Abstract

The invention provides a polyurethane antifouling paint, a preparation method thereof and a polyurethane antifouling coating, and belongs to the technical field of paints. The polyurethane antifouling paint comprises a cross-linkable part and a non-cross-linked resin part, wherein the cross-linkable part comprises a second prepolymer formed by reaction of polyether polyol, dihydroxyl long-chain quaternary ammonium salt and diisocyanate; the non-crosslinked resin part comprises linear or branched chain polyurethane grafted with a sterilizing agent, and the sterilizing agent comprises 3-iodine-2-propynyl-N-n-butyl carbamate. The polyurethane antifouling coating provided by the invention can provide a relatively long-acting antifouling effect in a fresh water environment, the dihydroxyl long-chain quaternary ammonium salt and the bactericide can inactivate protein in contact with the coating, and meanwhile, the reduced free energy on the surface of the polyurethane antifouling coating promotes desorption of surface fouling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coating, in particular to a polyurethane antifouling coating, a preparation method thereof and a polyurethane antifouling coating. BACKGROUND

[0002] When an object is in a wet or submerged condition, it is more likely to have microorganisms or plants and animals attached to the surface, resulting in the formation of fouling on the surface of the object. For example, part of the hull of a ship is submerged in water (e.g. seawater), and the submerged part may have various biological fouling, such as mussels, algae, etc. The fouling of the hull increases the frictional resistance of the ship during navigation, increases fuel consumption, and the biological fouling may also endanger the safety of the hull structure.

[0003] In a freshwater environment, similar biological fouling also occurs. For example, a large number of clams are found in the water resource allocation projects of the Yangtze River and the Pearl River. The clams are attached to the surface of concrete and metal pipes, corrode the engineering materials, and thus affect the safety of the water conservancy project. At present, the related technology uses silicone coating to reduce the attachment of clams, and although the silicone coating has good antifouling effect on microorganisms, the adhesion of the silicone coating to the surface of the base layer is poor, and the mechanical properties of the silicone coating are poor, which is difficult to meet the requirements of water conservancy projects. SUMMARY

[0004] Therefore, in order to at least partially solve the above-mentioned technical problems, the present application provides a polyurethane antifouling coating, a preparation method thereof and a polyurethane antifouling coating.

[0005] According to an embodiment of one aspect of the present application, a polyurethane antifouling coating is provided, comprising a cross-linkable part and a non-cross-linking resin part; wherein the cross-linkable part comprises a second prepolymer formed by reacting a polyether polyol, a diisocyanate and a double-hydroxyl long-chain quaternary ammonium salt; and the non-cross-linking resin part comprises a linear or branched polyurethane grafted with a bactericide, the bactericide comprising 3-iodo-2-propynyl-N-n-butyl carbamate.

[0006] In some embodiments, the mass percentage of the non-cross-linking resin part is 5-15% based on the total mass of the polyurethane antifouling coating.

[0007] In some embodiments, the double-hydroxyl long-chain quaternary ammonium salt has the following structure shown in formula (I):

[0008] Formula (I), wherein R1 is selected from C1-C3 alkyl, R2 is selected from C 14 ~C 24 alkyl.

[0009] According to embodiments of another aspect of the present application, there is provided a method for preparing the polyurethane antifouling coating as described above, comprising: mixing the dehydrated polyether polyol and diisocyanate in an organic solvent to perform a first isocyanate end-capping reaction to obtain a first prepolymer; grafting the first prepolymer with the bactericide under the catalysis of a first catalyst to obtain a linear or branched polyurethane grafted with the bactericide, and further to obtain a non-crosslinkable resin part of the polyurethane antifouling coating; dehydrating the polyether polyol and the dihydroxy long-chain quaternary ammonium salt, and performing a second isocyanate end-capping reaction with diisocyanate in an organic solvent under the catalysis of a second catalyst to obtain a second prepolymer, and further to form a crosslinkable part of the polyurethane antifouling coating; and mixing the non-crosslinkable resin part and the crosslinkable part to obtain the polyurethane antifouling coating; the bactericide comprising 3-iodo-2-propynyl-N-n-butyl carbamate.

[0010] In some embodiments, in the crosslinkable part, the molar ratio of isocyanate groups to hydroxyl groups is (1.9-2.2):1; and in the non-crosslinkable resin part, the molar ratio of hydroxyl groups from the polyether polyol, diisocyanate and the bactericide is 1:(0.95-1.05):(1.05-1.1).

[0011] In some embodiments, in the crosslinkable part, the polyether polyol has a hydroxyl value of 25-120 mgKOH / g, and in the non-crosslinkable resin part, the polyether polyol has a hydroxyl value of 13-60 mgKOH / g.

[0012] In some embodiments, in the crosslinkable part and the non-crosslinkable resin part, the polyether polyol is independently selected from at least one of polypropylene oxide, ethylene oxide-propylene oxide block copolymer, polytetrahydrofuran.

[0013] In some embodiments, in the crosslinkable part, the polyether polyol has an average functionality of 2.15-2.85, and in the non-crosslinkable resin part, the polyether polyol has an average functionality of 2-2.25.

[0014] In some embodiments, in the crosslinkable part and the non-crosslinkable resin part, the diisocyanate is independently selected from at least one of toluene diisocyanate, diphenyl methane diisocyanate, dicyclohexyl methane diisocyanate, isophorone diisocyanate.

[0015] In some embodiments, the reaction conditions of the first prepolymer are as follows: after mixing the polyether polyol and diisocyanate, the temperature is raised to 80-100°C for 4-6 h.

[0016] In some embodiments, the first prepolymer, the bactericide and the first catalyst are mixed and stirred at a temperature of 50-70℃ for 1-3h to obtain the non-crosslinked resin part; the first catalyst comprises N-methyl-N-(N,N-dimethylaminoethyl) ethanolamine.

[0017] In some embodiments, the second prepolymer is synthesized under the following conditions: the polyether polyol and the dihydroxy long-chain quaternary ammonium salt are heated and mixed, the diisocyanate is added and heated to 70-90℃ for 2-4h, and the second catalyst is added and the reaction is continued for 0.5-1h; the second catalyst comprises dibutyl tin dilaurate.

[0018] According to an embodiment of the application, the polyurethane antifouling coating is formed by coating the polyurethane antifouling paint on a metal or concrete surface, reacting with moisture at room temperature to form a semi-interpenetrating network structure antifouling coating formed by the crosslinkable part and the non-crosslinked resin part.

[0019] According to the polyurethane antifouling paint of the application, the introduction of the dihydroxy long-chain quaternary ammonium salt provides bactericidal effect on part of the coating surface, and reduces the surface free energy of the polyurethane antifouling paint after forming a coating, which helps to make the biological fouling more easily detached and reduce its adhesion. The non-crosslinked resin part is grafted with the bactericide, which further provides contact bactericidal effect of the coating, forms a microbial barrier on the coating surface to avoid the growth of microorganisms on the coating surface to form a biofilm. The polyurethane antifouling paint of the application retains the characteristics of high strength, high elasticity and high adhesion of polyurethane materials, which helps to improve the service life of the antifouling coating. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the application will be described in detail. For the purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the application. It will be apparent, however, that one or more embodiments can be practiced without these specific details. In other instances, well-known structures and techniques have not been described in order to avoid obscuring the understanding of this description.

[0021] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "includes" indicates the presence of the features, steps, operations, etc. but not the exclusion of one or more other features.

[0022] In the case of using expressions similar to "at least one of A, B, or C", etc., it is generally intended to mean any of the following: "only A", "only B", "only C", "at least one of A and B", "at least one of A and C", "at least one of B and C", "at least one of A, B, and C", etc.

[0023] The related art attempts to reduce the effect of the attachment of microorganisms, such as mussels, barnacles, algae, and the like, by adding a coating layer on the base layer. For example, a coating layer is formed by coating the surface of the base layer with a silicone coating. Although the silicone coating has the advantages of a low modulus of elasticity and a low surface free energy, and can reduce the effect of the attachment of fouling organisms to a certain extent, the adhesion between the silicone coating and the base layer (such as metal or concrete) is poor, and the mechanical properties are low, and it is difficult to continuously apply.

[0024] In the present application, "biofouling" can be understood as bioaccumulation, which can be the unnecessary accumulation and growth of aquatic organisms (such as microorganisms, plants, algae, and animals) on natural or artificial surfaces immersed in water, for example, on metal or concrete surfaces. The accumulation of biofouling increases the sailing resistance of a ship in water, increases fuel consumption, and at the same time damages the anticorrosive coating of the ship body. In water resource allocation engineering, biofouling is attached to the surface of concrete and metal pipes, corrodes the engineering materials, and affects the safety of water conservancy projects.

[0025] In the process of implementing the present application, it is found that the polysiloxane terminated with a hydroxyl group or an amine group and the antifouling agent containing a hydroxyl group are used to form a polyurethane antifouling coating by using a polyisocyanate, the easy detachment of fouling of the silicone is used, and the attachment of algae is inhibited by using the antifouling agent. However, the price of the hydroxyl-terminated or amine-terminated polysiloxane is relatively high, and the chemical reaction process of introducing a hydroxyl group into the antifouling agent is relatively complex, the cost is too high, and it is difficult to be practically popularized.

[0026] Further, in order to solve the above-mentioned problems, the bactericide is grafted into the linear or branched polyurethane by a chemical bond in the present application, and then the linear or branched polyurethane is mixed with a cross-linkable part to form a polyurethane antifouling coating. After curing with moisture, a semi-interpenetrating network is formed, which limits the linear or branched polyurethane containing the bactericide from seeping out of the coating to affect the quality of the water environment after the subsequent formation of the coating, and the non-cross-linked resin part (linear or branched polyurethane containing the bactericide) can migrate to the surface of the coating to achieve a high-efficiency bactericidal effect. In addition, the dihydroxy long-chain quaternary ammonium salt is introduced into the cross-linkable part, which helps to reduce the surface free energy of the polyurethane antifouling coating and achieve easy detachment of biofouling.

[0027] According to an embodiment of one aspect of the present application, a polyurethane antifouling coating is provided, which comprises a cross-linkable part and a non-cross-linked resin part; wherein the cross-linkable part comprises a second prepolymer formed by the reaction of a polyether polyol, a diisocyanate, and a dihydroxy long-chain quaternary ammonium salt; and the non-cross-linked resin part comprises a linear or branched polyurethane grafted with a bactericide, and the bactericide comprises 3-iodo-2-propynyl-N-n-butyl carbamate.

[0028] According to the embodiment of the present application, the polyurethane antifouling coating of the present application comprises a cross-linkable part and a non-cross-linking resin part, wherein the polyether polyol, the dihydroxy long-chain quaternary ammonium salt and the diisocyanate in the cross-linkable part form a cross-linked polyurethane network structure, providing good adhesion to the base layer (such as metal or concrete, etc.), providing high mechanical strength and stability. The dihydroxy long-chain quaternary ammonium salt is introduced into the polyurethane network structure through cross-linking reaction, which can reduce the surface free energy of the coating formed after the curing of the polyurethane antifouling coating while contributing to the surface sterilization effect, realizing the easy detachment of biofouling. In the non-cross-linking resin part, the bactericide is grafted into the linear or branched polyurethane, limiting the exudation of the bactericide into the coating formed after curing, and the 3-iodo-2-propynyl-N-n-butyl carbamate (IPBC) grafted in the flexible non-cross-linking resin part can migrate to the surface of the coating relatively quickly to achieve high-efficiency sterilization effect, ensuring that the polyurethane antifouling coating is not easy to adhere to the active protein mucus such as bacteria and fungi through surface contact sterilization, so as to avoid the growth of complex microorganisms on the surface of the mucus layer to form macroscopic biofouling. Since the cross-linkable part and the non-cross-linking resin part both belong to polyurethane, they have good compatibility and will not separate, ensuring the uniformity and stability of the formed antifouling coating. In addition, the present application does not involve complex chemical modification and relatively expensive special raw materials, and has the potential for large-scale application.

[0029] It should be noted that the cross-linkable part and the non-cross-linking resin part of the present application are cured to form a protective coating after being subsequently brushed on the surface of the base layer, forming a semi-interpenetrating network structure. The semi-interpenetrating network structure can be understood as a three-dimensional network polyurethane structure (cross-linkable part) and a linear or branched polyurethane resin structure (non-cross-linking resin part) which are tightly combined through physical action to form a composite material. The three-dimensional network polyurethane structure provides a relatively strong and antibacterial network skeleton structure, and the non-cross-linking resin part acts as a functional carrier and is physically fixed in the aforementioned network skeleton structure.

[0030] The polyurethane antifouling coating of the present application does not release bactericides into the water environment, and uses surface contact sterilization to ensure that the subsequent cured antifouling coating is not easy to adhere to the active protein mucus such as bacteria and fungi, so as to avoid the growth of more complex microorganisms on the surface of the mucus to form a macroscopic biofouling coating.

[0031] It can be understood that the structure of 3-iodo-2-propynyl-N-n-butyl carbamate (IPBC) can be as shown in the following formula (II),

[0032] Formula (II).

[0033] In some embodiments, the mass percentage of the non-crosslinking resin part is 5-15% based on the total mass of the polyurethane antifouling coating. In this way, the semi-interpenetrating network structure can be formed while ensuring that the polyurethane antifouling coating has good mechanical properties. If the mass percentage of the non-crosslinking resin part is too low, it is difficult to provide sufficient sterilization effect; if the mass percentage of the non-crosslinking resin part is too high, the density of the non-crosslinking resin part dilutes the crosslinking network, and the mechanical properties of the formed coating are reduced.

[0034] Alternatively, the total mass percentage of the non-crosslinking resin part may, for example, be 5%, 7%, 9%, 11%, 13%, or 15%, or a range between any two of the above values.

[0035] In some embodiments, the dihydroxy long-chain quaternary ammonium salt has the following structure shown in formula (I):

[0036] Formula (I), wherein R1 is selected from C1-C3 alkyl, R2 is selected from C 14 ~C 24 alkyl. In this way, by chemically introducing the dihydroxy long-chain quaternary ammonium salt into the three-dimensional network structure of the crosslinkable part of the polyurethane, the negative impact on the water environment quality can be reduced, and the formed polyurethane antifouling coating can have a low surface free energy for a long time.

[0037] According to an embodiment of another aspect of the present application, a preparation method of the polyurethane antifouling coating is provided, which comprises steps A1-A3.

[0038] In step A1, the dehydrated polyether polyol and diisocyanate are mixed in an organic solvent to perform a first isocyanate capping reaction, and a first prepolymer is obtained.

[0039] In step A2, the first prepolymer is grafted with the sterilizing agent under the catalysis of a first catalyst to obtain a linear or branched polyurethane grafted with the sterilizing agent, and then a non-crosslinking resin part of the polyurethane antifouling coating is obtained.

[0040] In step A3, the dehydrated polyether polyol and dihydroxy long-chain quaternary ammonium salt are subjected to a second isocyanate capping reaction with diisocyanate in an organic solvent under the catalysis of a second catalyst to obtain a second prepolymer, and then a crosslinkable part of the polyurethane antifouling coating is formed.

[0041] The products obtained in steps A2 and A3 are mixed to obtain the polyurethane antifouling coating.

[0042] According to embodiments of the present application, the biocide comprises 3-iodo-2-propynyl-N-n-butyl carbamate (IPBC). In Step Al and Step A2, the first prepolymer prepared has active isocyanate groups (-NCO) at both ends, and under the catalysis of the first catalyst, the grafting of IPBC is carried out, ensuring that the non-crosslinkable resin part does not contain active NCO groups. In this way, the grafting of the biocide (IPBC) is carried out first, and then mixed with the crosslinkable part, which can increase the biocidal effect of the polyurethane antifouling coating, and provide a plasticizing effect from the non-crosslinkable resin part. Step A3 helps to fix the long-chain quaternary ammonium salt with dihydroxy groups into the three-dimensional crosslinking network of the crosslinkable part, reduces the surface free energy of the coating formed subsequently, and at the same time strengthens the biocidal effect.

[0043] In some embodiments, in the crosslinkable part, the molar ratio of isocyanate groups to hydroxyl groups is (1.9~2.2):1. In this way, after the hydroxyl groups in the crosslinkable part are completely consumed, there are still isocyanate groups at the ends of the second prepolymer, which are prepared for subsequent curing reaction with moisture in the environment, prompting the formation of urea bonds after moisture curing, so that the formed coating has excellent mechanical strength, and the bonding strength with the base layer is improved.

[0044] Alternatively, in the crosslinkable part, the molar ratio of isocyanate groups to hydroxyl groups may, for example, be 1.9:1, 2:1, 2.1:1, or 2.2:1, or a range composed between any two of the above values.

[0045] In some embodiments, in the non-crosslinkable resin part, the molar ratio of hydroxyl groups from the polyether polyol, diisocyanate, and biocide is 1:(0.95~1.05):(1.05~1.1). In this way, it helps to fully react the hydroxyl groups in the polyether polyol to form a first prepolymer capped with isocyanate groups; the further excess of biocide ensures that the end groups of the aforementioned first prepolymer can be fully grafted with IPBC, and the further excess of IPBC drives the reaction to proceed in the forward direction, promoting the formation of linear or branched polyurethane grafted with biocide, avoiding the influence of the first prepolymer with residual -NCO groups on the subsequent process.

[0046] Alternatively, in the non-crosslinkable resin part, the molar ratio of hydroxyl groups from the polyether polyol, diisocyanate, and biocide may, for example, be 1:1:1.05, 1:1.05:1.1, or a range composed between any two of the above values.

[0047] In some embodiments, the polyether polyol in the cross-linkable portion has a hydroxyl value of 25-120 mgKOH / g, and the polyether polyol in the non-cross-linkable resin portion has a hydroxyl value of 13-60 mgKOH / g. In this way, the polyether polyol with a higher hydroxyl value is used in the cross-linkable portion to construct a three-dimensional network skeleton with higher cross-linking density and toughness, and the polyether polyol with a lower hydroxyl value is used in the non-cross-linkable resin portion to obtain a linear or branched polyurethane with longer molecular chain, better flexibility and hydrophobicity, which can carry and inhibit the leaching of the biocide.

[0048] Alternatively, the polyether polyol in the cross-linkable portion can have a hydroxyl value of, for example, 25 mgKOH / g, 28 mgKOH / g, 50 mgKOH / g, 56 mgKOH / g, 100 mgKOH / g, 112 mgKOH / g, 120 mgKOH / g, or a range between any two of the above values.

[0049] Alternatively, the polyether polyol in the non-cross-linkable resin portion can have a hydroxyl value of, for example, 13 mgKOH / g, 14 mgKOH / g, 28 mgKOH / g, 35 mgKOH / g, 56 mgKOH / g, or 60 mgKOH / g, or a range between any two of the above values.

[0050] In some embodiments, the polyether polyol in the cross-linkable portion and the non-cross-linkable resin portion is independently selected from at least one of polypropylene oxide, ethylene oxide-propylene oxide block copolymer, and polytetrahydrofuran. In this way, the chemical properties of the ether bond of the polyether polyol are relatively stable, and the main chain will not be quickly degraded when immersed in a water environment (sea water or fresh water environment) for a long time, ensuring the durability and long-term effectiveness of the polyurethane coating formed.

[0051] It can be understood that the polyether polyol in the cross-linkable portion and the non-cross-linkable resin portion can be the same or different, and the present application does not make special limitation thereon.

[0052] In some embodiments, the polyether polyol in the cross-linkable portion has an average functionality of 2.15-2.85, and the polyether polyol in the non-cross-linkable resin portion has an average functionality of 2-2.25. It can be understood that the polyether polyol with a higher average functionality is used in the cross-linkable portion to promote the formation of a three-dimensional network skeleton with high cross-linking density and stability. In the non-cross-linkable resin portion, the average functionality is close to 2, which helps to prepare a linear or branched polyurethane, and then form an effective semi-interpenetrating network structure with the three-dimensional network skeleton after moisture curing.

[0053] In some embodiments, the diisocyanate in the cross-linkable portion and the non-cross-linkable resin portion is independently selected from at least one of toluene diisocyanate, diphenyl methane diisocyanate, dicyclohexyl methane diisocyanate, isophorone diisocyanate. It is understood that the diisocyanate used in the cross-linkable portion and the non-cross-linkable resin portion can be the same or different, and the present application does not make special limitations thereon.

[0054] In some embodiments, the reaction conditions of the first prepolymer are that after mixing the polyether polyol and the diisocyanate, the temperature is raised to 80-100°C, for example, it can be 80°C, 90°C or 100°C, and the reaction is carried out for 4-6h, for example, it can be 4h, 5h or 6h, etc.

[0055] In some embodiments, the reaction conditions of the grafting of the bactericide are that the first prepolymer, the bactericide and the first catalyst are mixed and stirred at 50-70°C, for example, it can be 50°C, 60°C or 70°C, for 1-3h, for example, it can be 1h, 2h or 3h.

[0056] In some embodiments, the first catalyst comprises N-methyl-N-(N,N-dimethylaminoethyl) ethanolamine. By adding the first catalyst, it helps to promote the grafting reaction between the bactericide and the first prepolymer, and grafts the bactericide molecules onto the linear or branched polyurethane.

[0057] In some embodiments, the water content of the dehydrated polyether polyol is less than 300ppm.

[0058] In some embodiments, in step A3, after the polyether polyol and the dihydroxy long chain quaternary ammonium salt are dehydrated, the water content is less than 300ppm.

[0059] In some embodiments, the synthesis conditions of the second prepolymer are that the polyether polyol and the dihydroxy long chain quaternary ammonium salt are heated and mixed at 50-70°C, for example, it can be 50°C, 60°C or 70°C, the diisocyanate is added and the temperature is raised to 70-90°C, for example, it can be 70°C, 80°C or 90°C, the reaction is carried out for 2-4h, for example, it can be 2h, 3h or 4h, the second catalyst is added and the reaction is continued for 0.5-1h, for example, it can be 0.5h, 0.75h or 1h. In this way, the mixture is promoted to carry out the isocyanate end-capping reaction in the organic solvent, and the isocyanate group end-capped second prepolymer is obtained.

[0060] In some embodiments, the second catalyst comprises dibutyl tin dilaurate.

[0061] In some embodiments, under the catalysis of the second catalyst, the synthesis reaction of the second prepolymer is promoted to proceed smoothly.

[0062] From the viewpoint of improving the solubility of several raw materials, an organic solvent such as xylene can be used.

[0063] According to an embodiment of the present application, there is provided a polyurethane antifouling coating formed by the aforementioned polyurethane antifouling coating material, which is applied on the surface of a substrate and cured by reacting with moisture at room temperature to form a semi-interpenetrating network structure formed by the cross-linkable portion and the non-cross-linkable resin portion.

[0064] According to an embodiment of the present application, the second prepolymer formed in the cross-linkable portion reacts with water to form urea bonds, thereby forming a three-dimensionally cross-linked polyurethane network. The non-cross-linkable resin portion physically penetrates and entangles in the three-dimensionally cross-linked network, thereby forming a semi-interpenetrating network structure. The semi-interpenetrating network structure strengthens the mechanical strength and the resistance to impact penetration of the coating, and the non-cross-linkable resin portion provides the flexibility and elasticity of the coating, thereby effectively reducing the cracking and peeling of the coating.

[0065] In some embodiments, the semi-interpenetrating network structure is formed by the cross-linked polyurethane network formed by the cross-linkable portion and the non-cross-linkable resin portion after the aforementioned polyurethane antifouling coating material is applied on the surface of a metal or concrete and cured by moisture under the catalysis of the second catalyst. The non-cross-linkable resin portion grafted with the biocide is mixed with the cross-linkable portion, and then applied on the surface of the metal or concrete after surface pretreatment, such as cleaning or sandblasting, by brushing, rolling or spraying, etc. to improve the adhesion strength. After application, the moisture in the air penetrates into the polyurethane antifouling coating material and participates in the curing process as a reactant to promote the curing of the polyurethane antifouling coating material to form a coating. The presence of the second catalyst helps to further promote the moisture curing process. The present application is further illustrated by the following examples and related test experiments and results. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, that one or more embodiments can be practiced without these specific details. In other instances, well-known methods have not been described in detail in order to not unnecessarily obscure the embodiments.

[0066] It should be noted that the following specific examples are only illustrative and the scope of the present application is not limited thereto. The chemicals and raw materials used in the following examples are commercially available or obtained by a recognized processing method.

[0067] Example 1:

[0068] Preparation process of the non-cross-linkable resin portion:

[0069] A mixture of 1000 g of polypropylene oxide polyol with a functionality of 2 and a hydroxyl value of 14 mgKOH / g, 42 g of toluene diisocyanate (TDI), and 100 g of xylene were stirred uniformly at 50°C, and then the temperature was raised to 90°C and reacted for 5 hours. After the temperature was lowered to 60°C, 66 g of 3-iodo-2-propynyl-N-n-butyl carbamate (IPBC) and 3 g of catalyst N-methyl-N-(N,N-dimethylaminoethyl) ethanolamine were added, and the reaction was performed for 2 hours. The non-crosslinking resin fraction was obtained by vacuum degassing after the reaction.

[0070] Preparation process of the mixture of the crosslinkable fraction and the non-crosslinking resin fraction:

[0071] A mixture of 500 g of polypropylene oxide polyol with a functionality of 2 and a hydroxyl value of 112 mgKOH / g, 250 g of ethylene oxide-propylene oxide copolymer polyol with a functionality of 3 and a hydroxyl value of 56 mgKOH / g, 100 g of the non-crosslinking resin fraction, and 45 g of butyl ester bis-hydroxyethyl methyl ammonium chloride was stirred uniformly, and then vacuum dehydration was performed at 110°C so that the water content was less than 300 ppm, thereby obtaining the mixture of the crosslinkable fraction and the non-crosslinking resin fraction.

[0072] Preparation process of the polyurethane antifouling coating having a semi-interpenetrating network structure:

[0073] The mixture of the crosslinkable fraction and the non-crosslinking resin fraction was heated to 60°C, and then 350 g of isophorone diisocyanate (IPDI), 2 g of dibutyl tin dilaurate, and 80 g of xylene were added. The temperature was raised to 80°C and the reaction was performed for 3 hours. After the temperature was lowered, the polyurethane antifouling coating having a semi-interpenetrating network structure was obtained by vacuum degassing.

[0074] Example 2:

[0075] The preparation process of the non-crosslinking resin fraction of Example 2 was the same as that of Example 1, and thus a detailed description thereof will not be given.

[0076] Preparation process of the mixture of the crosslinkable fraction and the non-crosslinking resin fraction:

[0077] A mixture of 500 g of polypropylene oxide polyol with a functionality of 2 and a hydroxyl value of 112 mgKOH / g, 250 g of ethylene oxide-propylene oxide copolymer polyol with a functionality of 3 and a hydroxyl value of 56 mgKOH / g, 100 g of the non-crosslinking resin fraction, and 45 g of butyl ester bis-hydroxyethyl methyl ammonium chloride was stirred uniformly, and then vacuum dehydration was performed at 110°C so that the water content was less than 300 ppm, thereby obtaining the mixture of the crosslinkable fraction and the non-crosslinking resin fraction.

[0078] Preparation process of the polyurethane antifouling coating having a semi-interpenetrating network structure:

[0079] The mixture of the crosslinkable and non-crosslinkable resin parts was heated to 60°C, and 275g of toluene diisocyanate, 0.5g of dibutyltin dilaurate and 100g of xylene were added. The mixture was then heated to 80°C and reacted for 3 hours. After cooling, the mixture was degassed under vacuum and stored for later use to obtain a polyurethane antifouling coating with a semi-interpenetrating network structure.

[0080] Example 3:

[0081] Preparation process of the non-crosslinked resin portion:

[0082] 1000g of polypropylene oxide polyol with a hydroxyl value of 28mgKOH / g and a functionality of 2 was dehydrated under vacuum at 110℃ to reduce its water content to less than 300ppm. 84g of TDI and 100g of xylene were added at 50℃ and stirred until homogeneous. The mixture was then heated to 90℃ and reacted for 5 hours. The temperature was lowered to 60℃ and 132g of IPBC and 3g of catalyst N-methyl-N-(N,N-dimethylaminoethyl)ethanolamine were added. After reacting for 2 hours, the mixture was degassed under vacuum for later use to obtain the non-crosslinked resin fraction.

[0083] Preparation process of a mixture of crosslinkable and non-crosslinkable resin portions:

[0084] 500g of a polypropylene oxide polyol with a hydroxyl value of 112mgKOH / g and a functionality of 2, 250g of an ethylene oxide-propylene oxide copolymer polyol with a hydroxyl value of 56mgKOH / g and a functionality of 3, 100g of the above-mentioned non-crosslinked resin portion, and 45g of tallow-based dihydroxyethyl methyl ammonium chloride were stirred evenly and then vacuum dehydrated at 110°C to reduce the water content to below 300ppm, resulting in a mixture of the crosslinkable portion and the non-crosslinked resin portion.

[0085] Preparation process of polyurethane antifouling coating with semi-interpenetrating network structure:

[0086] The mixture of the crosslinkable and non-crosslinkable resin parts was heated to 60°C, and 350g of IPDI, 2g of dibutyltin dilaurate and 80g of xylene were added. The mixture was heated to 80°C and reacted for 3 hours. After cooling, the mixture was degassed under vacuum and stored for later use to obtain a polyurethane antifouling coating with a semi-interpenetrating network structure.

[0087] Example 4:

[0088] The preparation process of the non-crosslinked resin portion in Example 4 is the same as that in Example 3, and will not be repeated here.

[0089] Preparation process of a mixture of crosslinkable and non-crosslinkable resin portions:

[0090] 500g of a polypropylene oxide polyol with a hydroxyl value of 112mgKOH / g and a functionality of 2, 250g of an ethylene oxide-propylene oxide copolymer polyol with a hydroxyl value of 56mgKOH / g and a functionality of 3, 100g of the non-crosslinked resin portion obtained in Example 3, and 45g of tallow-based dihydroxyethyl methyl ammonium chloride were stirred evenly and then vacuum dehydrated at 110°C to reduce the water content to below 300ppm, resulting in a mixture of the crosslinkable portion and the non-crosslinked resin portion.

[0091] Preparation process of polyurethane antifouling coating with semi-interpenetrating network structure:

[0092] The mixture of the crosslinkable and non-crosslinkable resin parts was heated to 60°C, and 275g of TDI, 0.5g of dibutyltin dilaurate and 100g of xylene were added. The mixture was then heated to 80°C and reacted for 3 hours. After cooling, the mixture was degassed under vacuum and stored for later use to obtain a polyurethane antifouling coating with a semi-interpenetrating network structure.

[0093] Example 5:

[0094] Preparation process of the non-crosslinked resin portion:

[0095] 600g of a polypropylene oxide polyol with a hydroxyl value of 56mgKOH / g and a functionality of 2 and 400g of an ethylene oxide-propylene oxide copolymer polyol with a hydroxyl value of 35mgKOH / g and a functionality of 3 were vacuum dehydrated at 110℃ to reduce the water content to less than 300ppm. 148g of TDI and 100g of xylene were added at 50℃ and stirred until homogeneous. The mixture was then heated to 90℃ and reacted for 5 hours. The temperature was lowered to 60℃ and 238g of IPBC and 3g of the catalyst N-methyl-N-(N,N-dimethylaminoethyl)ethanolamine were added. After reacting for 2 hours, the mixture was degassed under vacuum for later use to obtain the non-crosslinked resin fraction.

[0096] Preparation process of a mixture of crosslinkable and non-crosslinkable resin portions:

[0097] 500g of a polypropylene oxide polyol with a hydroxyl value of 112mgKOH / g and a functionality of 2, 250g of an ethylene oxide-propylene oxide copolymer polyol with a hydroxyl value of 56mgKOH / g and a functionality of 3, 100g of the above-mentioned non-crosslinked resin portion, and 45g of tallow-based dihydroxyethyl methyl ammonium chloride were stirred evenly and then vacuum dehydrated at 110°C to reduce the water content to below 300ppm, resulting in a mixture of the crosslinkable portion and the non-crosslinked resin portion.

[0098] Preparation process of polyurethane antifouling coating with semi-interpenetrating network structure:

[0099] The mixture of the crosslinkable and non-crosslinkable resin parts was heated to 60°C, and 350g of IPDI, 2g of dibutyltin dilaurate and 80g of xylene were added. The mixture was heated to 80°C and reacted for 3 hours. After cooling, the mixture was degassed under vacuum and stored for later use to obtain a polyurethane antifouling coating with a semi-interpenetrating network structure.

[0100] Example 6:

[0101] Preparation process of the non-crosslinked resin portion:

[0102] 1000g of polypropylene oxide polyol with a hydroxyl value of 28mgKOH / g and a functionality of 2 was dehydrated under vacuum at 110℃ to reduce its water content to less than 300ppm. 84g of TDI and 100g of xylene were added at 50℃ and stirred until homogeneous. The mixture was then heated to 90℃ and reacted for 5 hours. The temperature was lowered to 60℃ and 132g of IPBC and 3g of catalyst N-methyl-N-(N,N-dimethylaminoethyl)ethanolamine were added. After reacting for 2 hours, the mixture was degassed under vacuum for later use to obtain the non-crosslinked resin fraction.

[0103] Preparation process of a mixture of crosslinkable and non-crosslinkable resin portions:

[0104] 250g of a polypropylene oxide polyol with a hydroxyl value of 56mgKOH / g and a functionality of 2, 125g of an ethylene oxide-propylene oxide copolymer polyol with a hydroxyl value of 28mgKOH / g and a functionality of 3, 50g of the above-mentioned non-crosslinked resin portion, and 23g of tallow-based dihydroxyethyl methyl ammonium chloride were stirred evenly and then vacuum dehydrated at 110°C to reduce the water content to below 300ppm, resulting in a mixture of the crosslinkable portion and the non-crosslinked resin portion.

[0105] Preparation process of polyurethane antifouling coating with semi-interpenetrating network structure:

[0106] The mixture of the crosslinkable and non-crosslinkable resin parts was heated to 60°C, and 175g of IPDI, 1g of dibutyltin dilaurate and 50g of xylene were added. The mixture was then heated to 80°C and reacted for 3 hours. After cooling, the mixture was degassed under vacuum and stored for later use to obtain a polyurethane antifouling coating with a semi-interpenetrating network structure.

[0107] Comparative Example 1:

[0108] 500g of a polypropylene oxide polyol with a hydroxyl value of 112mgKOH / g and a functionality of 2, 250g of an ethylene oxide-propylene oxide copolymer polyol with a hydroxyl value of 56mgKOH / g and a functionality of 3, and 45g of tallow-based dihydroxyethyl methyl ammonium chloride were stirred evenly and then dehydrated under vacuum at 110℃ to reduce the water content to below 300ppm. Then, 350g of IPDI, 2g of dibutyltin dilaurate, and 80g of xylene were added at 60℃, and the mixture was heated to 80℃ and reacted for 3 hours. After cooling, the mixture was degassed under vacuum and set aside for later use.

[0109] Comparative Example 2:

[0110] Preparation process of non-crosslinked resin portion without IPBC structure:

[0111] 1000g of polypropylene oxide polyol with a hydroxyl value of 28mgKOH / g and a functionality of 2 was dehydrated under vacuum at 110℃ to reduce its water content to less than 300ppm. 84g of TDI and 100g of xylene were added at 50℃ and stirred until homogeneous. The temperature was raised to 90℃ and reacted for 5 hours. The temperature was lowered to 60℃ and 24g of ethanol and 3g of dibutyltin dilaurate catalyst were added. After reacting for 2 hours, the mixture was degassed under vacuum for later use to obtain the non-crosslinked resin fraction.

[0112] Preparation process of a mixture of crosslinkable and non-crosslinkable resin portions:

[0113] 500g of a polypropylene oxide polyol with a hydroxyl value of 112mgKOH / g and a functionality of 2, 250g of an ethylene oxide-propylene oxide copolymer polyol with a hydroxyl value of 56mgKOH / g and a functionality of 3, 100g of the above-mentioned non-crosslinked resin portion without IPBC structure, and 45g of tallow-based dihydroxyethyl methyl ammonium chloride were stirred evenly and then vacuum dehydrated at 110°C to reduce the water content to below 300ppm, resulting in a mixture of the crosslinkable portion and the non-crosslinked resin portion.

[0114] Preparation process of polyurethane coatings with semi-interpenetrating network structure:

[0115] The mixture of the crosslinkable and non-crosslinkable resin parts was heated to 60°C, and 350g of IPDI, 2g of dibutyltin dilaurate and 80g of xylene were added. The mixture was heated to 80°C and reacted for 3 hours. After cooling, the mixture was degassed under vacuum and stored for later use to obtain a polyurethane coating with a semi-interpenetrating network structure.

[0116] Comparative Example 3:

[0117] Preparation process of non-crosslinked resin moieties containing IPBC structures:

[0118] 1000g of polypropylene oxide polyol with a hydroxyl value of 28mgKOH / g and a functionality of 2 was dehydrated under vacuum at 110℃ to reduce its water content to less than 300ppm. 84g of TDI and 100g of xylene were added at 50℃ and stirred until homogeneous. The mixture was then heated to 90℃ and reacted for 5 hours. The temperature was lowered to 60℃ and 132g of IPBC and 3g of catalyst N-methyl-N-(N,N-dimethylaminoethyl)ethanolamine were added. After reacting for 2 hours, the mixture was degassed under vacuum for later use, yielding a non-crosslinked resin fraction containing the IPBC structure.

[0119] Preparation process of a mixture of crosslinkable and non-crosslinkable resin portions:

[0120] 500g of a polypropylene oxide polyol with a hydroxyl value of 112mgKOH / g and a functionality of 2, 250g of an ethylene oxide-propylene oxide copolymer polyol with a hydroxyl value of 56mgKOH / g and a functionality of 3, and 100g of the above-mentioned non-crosslinked resin portion containing the IPBC structure were stirred evenly and then vacuum dehydrated at 110°C to reduce the water content to below 300ppm, resulting in a mixture of the crosslinkable portion and the non-crosslinked resin portion.

[0121] Preparation process of polyurethane coatings with semi-interpenetrating network structure:

[0122] The mixture of the crosslinkable and non-crosslinkable resin parts was heated to 60°C, and 280g of IPDI, 2g of dibutyltin dilaurate and 80g of xylene were added. The mixture was heated to 80°C and reacted for 3 hours. After cooling, the mixture was degassed under vacuum and stored for later use to obtain a polyurethane coating with a semi-interpenetrating network structure.

[0123] Comparative Example 4:

[0124] 500g of polypropylene oxide polyol with a hydroxyl value of 112mgKOH / g and a functionality of 2 and 250g of ethylene oxide-propylene oxide copolymer polyol with a hydroxyl value of 56mgKOH / g and a functionality of 3 were stirred evenly and then dehydrated under vacuum at 110℃ to reduce the water content to less than 300ppm. 280g of IPDI, 2g of dibutyltin dilaurate and 80g of xylene were added at 60℃, and the mixture was heated to 80℃ and reacted for 3 hours. After cooling, the mixture was degassed under vacuum and set aside for later use.

[0125] The coatings prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were used to prepare coatings. The conditions for forming the coatings were as follows: the coatings were applied to the substrate at 23±2℃ and 50±10% relative humidity, and cured under these conditions for 7 days to obtain the coating.

[0126] The contact angles of water and diiodomethane on the surfaces of the coatings formed in Examples 1-6 and Comparative Examples 1-4 were measured using the seated drop method. The seated drop method involves dropping a small amount of deionized water (or diiodomethane) onto a horizontally placed coating surface using a microsyringe. Due to the interaction between the surface tension and the surface energy of the coating, the deionized water (or diiodomethane) forms a droplet. The droplet profile is captured by image capture, and the contact angle at the point where the droplet intersects the coating surface is calculated. Using the Owens-Wendt method, the surface free energy of the coating is calculated by measuring the contact angle of the deionized water (or diiodomethane) on the coating surface and combining this with the surface tension parameters of the liquid. Table 1 below shows the contact angle, surface free energy, and mechanical properties of the coatings in the embodiments and comparative examples of this invention.

[0127] Table 1

[0128]

[0129] As shown in Table 1, the surface free energy of the coatings in Examples 1-6, as well as Comparative Examples 1 and 2, is lower than that in Comparative Examples 3 and 4. This is because the ester-based dihydroxyethyl methyl ammonium chloride in the crosslinkable portion of the coating introduces long-chain alkyl groups into the polyurethane segments, reducing the surface free energy of the coating. Furthermore, the ester-based dihydroxyethyl methyl ammonium chloride not only reduces the surface free energy of the coating but also significantly increases its tensile strength. This may be because a small amount of charged ester-based dihydroxyethyl methyl ammonium chloride can utilize Coulomb forces to increase the cohesive energy of the hard segments of the polyurethane, thereby improving the tensile strength of the coating. The examples and comparative examples of this invention all exhibit high adhesive strength, with pull-out strengths on concrete surfaces all >2 MPa, demonstrating the good adhesion of the polyurethane coating to the substrate.

[0130] The coatings prepared in the above embodiments and comparative examples were tested on a hanging board in the field for one year. The results are shown in Table 2 below.

[0131] Table 2

[0132]

[0133] As shown in Table 2, it can be seen that in Examples 1 to 6, the polyurethane antifouling coating based on a specific semi-interpenetrating network structure placed in a freshwater environment showed no mussel attachment during a year of use. However, Comparative Example 1 did not form a semi-interpenetrating network structure and did not graft a bactericide, resulting in the attachment of a small number of mussels and a large number of algae. Comparative Example 2, although forming a semi-interpenetrating network structure, also did not graft a bactericide, resulting in the attachment of a small number of mussels and a large number of algae. Comparative Example 3, lacking a dihydroxy long-chain quaternary ammonium salt, had difficulty reducing surface free energy, leading to the attachment of a large number of mussels. Comparative Example 4, lacking a dihydroxy long-chain quaternary ammonium salt and without preparing a non-crosslinked resin portion grafted with a bactericide, resulted in the attachment of a large number of mussels.

[0134] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polyurethane antifouling coating, comprising a crosslinkable portion and a non-crosslinkable resin portion; in, The crosslinkable portion includes: a second prepolymer formed by the reaction of polyether polyol, diisocyanate and dihydroxy long-chain quaternary ammonium salt; The non-crosslinked resin portion comprises linear or branched polyurethane grafted with a bactericide, the bactericide being 3-iodo-2-propynyl-N-n-butylcarbamate.

2. The polyurethane antifouling coating according to claim 1, wherein, The non-crosslinked resin portion accounts for 5-15% of the total mass of the polyurethane antifouling coating.

3. The polyurethane antifouling coating according to claim 1, wherein, The dihydroxy long-chain quaternary ammonium salt has the structure shown in formula (I): Formula (I), wherein R1 is selected from C1~C3 alkyl groups and R2 is selected from C 14 ~C 24 alkyl.

4. A method for preparing a polyurethane antifouling coating as described in any one of claims 1 to 3, comprising: The dehydrated polyether polyol and diisocyanate were mixed in an organic solvent to carry out the first isocyanate end-capping reaction to obtain the first prepolymer; The first prepolymer is grafted with a bactericide under the catalysis of a first catalyst to obtain a linear or branched polyurethane grafted with a bactericide, thereby obtaining the non-crosslinked resin portion of the polyurethane antifouling coating. After dehydration of polyether polyol and dihydroxy long-chain quaternary ammonium salt, under the catalysis of a second catalyst, they undergo a second isocyanate end-capping reaction with diisocyanate in an organic solvent to generate a second prepolymer, which then forms the crosslinkable part of the polyurethane antifouling coating. The polyurethane antifouling coating is obtained by mixing the non-crosslinkable resin portion and the crosslinkable portion. The bactericide includes 3-iodo-2-propynyl-N-n-butylcarbamate.

5. The preparation method according to claim 4, wherein, In the crosslinkable portion, the molar ratio of isocyanate groups to hydroxyl groups is (1.9~2.2):1; In the non-crosslinkable resin portion, the molar ratio of the hydroxyl groups from the polyether polyol, the diisocyanate, and the bactericide is 1:(0.95~1.05):(1.05~1.1).

6. The preparation method according to claim 4, wherein, In the crosslinkable portion, the hydroxyl value of the polyether polyol is 25~120 mgKOH / g, and in the non-crosslinkable resin portion, the hydroxyl value of the polyether polyol is 13~60 mgKOH / g. And / or, In both the crosslinkable portion and the non-crosslinkable resin portion, the polyether polyol is independently selected from at least one of polypropylene oxide, ethylene oxide-propylene oxide block copolymer, and polytetrahydrofuran.

7. The preparation method according to claim 4, wherein, In the crosslinkable portion, the average functionality of the polyether polyol is 2.15 to 2.85, and in the non-crosslinkable resin portion, the average functionality of the polyether polyol is 2 to 2.

25. In both the crosslinkable portion and the non-crosslinkable resin portion, the diisocyanate is independently selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate.

8. According to the preparation method of claim 4, the reaction conditions for the first prepolymer are: mixing the polyether polyol and diisocyanate, and then heating to 80-100℃ for 4-6 hours; the grafting reaction conditions for the bactericide are: mixing and stirring the first prepolymer, bactericide, and first catalyst at 50-70℃ for 1-3 hours; wherein, The first catalyst comprises N-methyl-N-(N,N-dimethylaminoethyl)ethanolamine.

9. The preparation method according to claim 4, wherein, The synthesis conditions of the second prepolymer are as follows: polyether polyol and dihydroxy long-chain quaternary ammonium salt are heated and mixed, diisocyanate is added and the temperature is raised to 70~90℃ for 2~4h, and the second catalyst is added to continue the reaction for 0.5-1h; the second catalyst includes dibutyltin dilaurate.

10. A polyurethane antifouling coating, wherein the polyurethane antifouling coating is formed by applying an urethane antifouling coating as described in any one of claims 1 to 3 to a substrate surface and reacting and curing with moisture at room temperature, and has a semi-interpenetrating network structure formed by crosslinkable portions and non-crosslinkable resin portions.

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