A temperature-sensitive low surface energy antifouling coating and preparation method thereof

Abstract

The present invention relates to the field of coating technology, and in particular to a temperature-sensitive low-surface-energy antifouling coating and a preparation method thereof. The coating comprises the following components: 20 to 70 parts of a low-surface-energy resin, 0.1 to 20 parts of a fluorinated modified halloysite loaded with a temperature-sensitive antifouling agent, 0 to 45 parts of a pigment or filler, 0.5 to 5 parts of an additive, and 10 to 50 parts of a solvent; the low-surface-energy resin is a polydimethylsiloxane-based polyurea resin or a polydimethylsiloxane-based polyurethane resin; the fluorinated modified halloysite loaded with a temperature-sensitive antifouling agent is prepared by adding the fluorinated modified halloysite to an ethanol solution of the temperature-sensitive antifouling agent, mixing the mixture, and then filtering, washing, and freeze-drying. The antifouling coating provided by the present invention has a low surface energy coating, good bonding properties with an epoxy primer, and can automatically regulate the release rate of the non-toxic antifouling agent as the temperature changes, thereby improving the antifouling effect of the low-surface-energy antifouling coating under static conditions and achieving the purpose of high efficiency and long-term antifouling.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, in particular to a temperature-sensitive low-surface-energy antifouling coating and a preparation method thereof. Background Art

[0002] At present, marine antifouling coating technology is the most effective way to solve the problem of marine fouling. There are two main types of commercial applications of this technology:

[0003] One is a tin-free self-polishing coating containing toxic antifouling agents (such as cuprous oxide). This type of material kills or repels fouling organisms by releasing antifouling agents, but the toxicity of antifouling agents can have an adverse impact on marine ecology.

[0004] The second is the fouling of desorbable coatings (e.g. silicone elastomers based on polydimethylsiloxane). These materials have low surface energy (15-30 mJ / m 2 ) and a low elastic modulus make fouling organisms difficult to attach to their surfaces or easily desorb after attaching. From the perspective of environmental protection, fouling-removable coatings are the most ideal antifouling materials. However, these coatings have poor adhesion to epoxy substrates, requiring the use of a special tie paint. They also have poor mechanical properties and are prone to breakage and shedding. They also have poor fouling-removal capabilities under static conditions (such as slow-speed or stationary ships, oil platforms, and deep-sea fishing grounds), and their antifouling capabilities against bacteria, algae, and other fouling agents are particularly unsatisfactory. Furthermore, low-surface-energy antifouling coatings are typically manufactured as two- or three-component coatings, making their production, storage, and application inconvenient.

[0005] To address the above shortcomings, researchers have adopted physical blending or chemical modification methods to improve their performance. For example, the Chinese invention patent application number CN201910854210.X discloses a water-based low surface energy antifouling coating, its preparation method, and application. The formula physically blends halogenated furanone-chitosan derivative microspheres. The excellent antifouling ability of halogenated furanone is combined with the efficient antibacterial and antibacterial effects of chitosan derivatives to enhance the antifouling performance of the water-based low surface energy coating. The Chinese invention patent application number CN201110143379.8 discloses a quaternary ammonium salt-modified silicone polyurethane marine antifouling coating, its preparation method, and application. By chemically grafting side chains containing quaternary ammonium salts onto the silicone polyurethane chain, the low surface coating has bactericidal properties, thereby achieving a good antifouling effect.

[0006] The above-mentioned technologies have improved the antifouling performance of low-surface coatings to a certain extent. However, the attachment of marine fouling organisms to underwater surfaces is related to seawater temperature. It is generally believed that as seawater temperature rises, the reproduction, growth, and activity of various marine organisms increase, and the rate of marine organism attachment to underwater surfaces increases. Data shows that in 1997, the average surface seawater temperature in various sea areas in my country ranged from 1.01°C to 21.63°C in winter and 24.76°C to 29.42°C in summer. Seawater temperatures vary across seasons and sea areas, and the growth of marine fouling organisms has off-season and peak seasons, which impose different requirements on the antifouling performance of antifouling coatings. The above-mentioned technologies also cannot achieve long-term sustained release of antifouling agents or adaptively adjust the release rate for off-season and peak seasons.

[0007] Therefore, the development of a temperature-sensitive low surface energy antifouling coating that is environmentally friendly and pollution-free, has good adhesion and is not easy to fall off, and can adaptively adjust the antifouling performance according to the off-season and peak season is of great significance. Summary of the Invention

[0008] To address the problems of the prior art mentioned in the background art, the present invention provides a temperature-sensitive, low-surface-energy antifouling coating and its preparation method. This coating utilizes a single-component polydimethylsiloxane-based polyurea resin or a polydimethylsiloxane-based polyurethane resin as a base resin and a novel, non-toxic, temperature-sensitive antifouling agent supported by fluorinated halloysite. This coating effectively slows the release of the antifouling agent and can automatically regulate the release rate of the antifouling agent as the ambient temperature changes, thereby achieving efficient and long-lasting antifouling. The technical solution is as follows:

[0009] The temperature-sensitive low-surface-energy antifouling coating is characterized in that it comprises the following components, measured in parts by weight: 20 to 70 parts of a low-surface-energy resin, 0.1 to 20 parts of a fluorinated modified halloysite loaded with a temperature-sensitive antifouling agent, 0 to 45 parts of a pigment or filler, 0.5 to 5 parts of an additive, and 10 to 50 parts of a solvent; wherein the low-surface-energy resin is a polydimethylsiloxane-based polyurea resin or a polydimethylsiloxane-based polyurethane resin; and the fluorinated modified halloysite loaded with a temperature-sensitive antifouling agent is prepared by adding the fluorinated modified halloysite to an ethanol solution of the temperature-sensitive antifouling agent, mixing the mixture, and then filtering, washing, and freeze-drying the mixture.

[0010] In some embodiments, the preparation process of the fluorinated modified halloysite loaded with the temperature-sensitive antifouling agent is as follows:

[0011] The halloysite is calcined at 300-1000° C. for 1-3 hours and then ground into powder to obtain heat-activated halloysite; a fluorine-containing silane coupling agent is dissolved in anhydrous toluene, the heat-activated halloysite is added, and the mixture is stirred evenly; the temperature is then raised to 110-130° C., and the mixture is stirred, condensed, and refluxed in an anhydrous environment for 6-24 hours, and then cooled to room temperature, filtered, and washed with toluene. The solid residue is dried at 60-100° C. for 6-24 hours, and then crushed and sieved to obtain fluorinated modified halloysite.

[0012] The fluorinated modified halloysite is added to an ethanol solution of a temperature-sensitive antifouling agent and mixed evenly to obtain a mixed system; the mixed system is stirred: the mixed system is placed under vacuum conditions and stirred for a first time for 20 to 40 minutes, and then the mixed system is restored to normal pressure conditions and stirred for a second time for 10 to 20 minutes; wherein the stirring process is repeated 2 to 5 times; the stirred mixed system is filtered, washed, freeze-dried, and ground to obtain the fluorinated modified halloysite loaded with the temperature-sensitive antifouling agent.

[0013] In some embodiments, the mass ratio of the halloysite and the fluorinated silane coupling agent is 1:0.5-3; the ratio of the fluorinated silane coupling agent to the anhydrous toluene is 0.01-0.5 mol:1L; the mass ratio of the fluorinated modified halloysite to the ethanol solution of the temperature-sensitive antifouling agent is 1:10-100, wherein the mass concentration of the temperature-sensitive antifouling agent in the ethanol solution of the temperature-sensitive antifouling agent is 0.1-30%.

[0014] In some embodiments, the temperature-sensitive antifouling agent is 2-octyl-2H-furan-5-one.

[0015] In some embodiments, the fluorine-containing silane coupling agent is a mixture of any one or more of heptafluorodecyltriethoxysilane, heptafluorodecyltrimethoxysilane, tridecafluorooctyltriethoxysilane, tridecafluorooctyltrimethoxysilane, nonafluorohexyltrimethoxysilane, and nonafluorohexyltriethoxysilane.

[0016] In some embodiments, the mass content of the polydimethylsiloxy segment in the low surface energy resin is 50-95%, preferably 80-90%, and the molecular weight Mn of the polydimethylsiloxy segment is 1000-6000 g / mol, preferably 1500-3000 g / mol.

[0017] In some embodiments, the color filler includes a pigment and a filler; the pigment is a mixture of any one or more of black iron oxide, red iron oxide, yellow iron oxide, carbon black, toluidine red, phthalocyanine blue and phthalocyanine green, and the filler is a mixture of any one or more of titanium dioxide, dolomite powder, talc powder and mica powder.

[0018] In some embodiments, the particle size of the pigment or filler is ≤50 μm.

[0019] In some embodiments, the auxiliary agent is a mixture of any one or more of polyamide wax, organic bentonite, fumed silica, and hydrogenated castor oil;

[0020] In some embodiments, the solvent is a mixture of any one or more of methyl isobutyl ketone, butanone, butyl acetate, xylene, n-butanol, and propylene glycol methyl ether acetate.

[0021] The present invention also provides a method for preparing the temperature-sensitive low surface energy antifouling coating as described above, comprising the following steps:

[0022] The fluorinated modified halloysite loaded with the temperature-sensitive antifouling agent and a portion of the solvent are mixed and stirred uniformly, and then ultrasonically dispersed in an ice-water bath for 10 to 30 minutes to obtain a fluorinated modified halloysite dispersion loaded with the temperature-sensitive antifouling agent;

[0023] Mix the low surface energy resin, additives and another part of the solvent and stir them evenly, then add pigments and fillers and disperse or grind them at high speed to a fineness of less than 60 μm, filter and obtain a resin powder dispersion;

[0024] The fluorinated modified halloysite dispersion loaded with the temperature-sensitive antifouling agent and the resin powder dispersion are mixed, stirred and dispersed evenly, and filtered to obtain the temperature-sensitive low surface energy antifouling coating.

[0025] Compared with the existing technology, the temperature-sensitive low surface energy antifouling coating provided by the present invention has the following advantages:

[0026] Beneficial effects:

[0027] This invention utilizes a single-component polydimethylsiloxane-based polyurea resin or polydimethylsiloxane-based polyurethane resin as the base resin, combined with a fluorinated, modified halloysite loaded with a temperature-sensitive antifouling agent, to provide a temperature-sensitive, low-surface-energy antifouling coating. This coating exhibits low surface energy and excellent adhesion to epoxy primers. Furthermore, the release rate of the non-toxic antifouling agent can be controlled with temperature, thereby enhancing the coating's antifouling effectiveness under static conditions and achieving high efficiency and long-lasting antifouling. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] The present invention provides an operational example of a method for preparing a temperature-sensitive low surface energy antifouling coating, comprising the following steps:

[0030] Step 1

[0031] The fluorinated modified halloysite loaded with the temperature-sensitive antifouling agent and a portion of the solvent are mixed and stirred uniformly, and then ultrasonically dispersed in an ice-water bath for 10 to 30 minutes to obtain a fluorinated modified halloysite dispersion loaded with the temperature-sensitive antifouling agent;

[0032] Step 2

[0033] Mix the low surface energy resin, additives and another part of the solvent and stir them evenly, then add pigments and fillers and disperse or grind them at high speed to a fineness of less than 60 μm, filter and obtain a resin powder dispersion;

[0034] Step 3

[0035] The fluorinated modified halloysite dispersion loaded with the temperature-sensitive antifouling agent and the resin powder dispersion are mixed, stirred and dispersed evenly, and filtered to obtain the temperature-sensitive low surface energy antifouling coating.

[0036] Wherein, the formula of the coating is:

[0037] The composition comprises the following components, measured by weight: 20-70 parts of a low-surface-energy resin, 0.1-20 parts of a fluorinated, modified halloysite loaded with a temperature-sensitive antifouling agent, 0-45 parts of a pigment or filler, 0.5-5 parts of an additive, and 10-50 parts of a solvent. The low-surface-energy resin is a polydimethylsiloxane-based polyurea resin or a polydimethylsiloxane-based polyurethane resin.

[0038] The operation example of the preparation method of the fluorinated modified halloysite loaded with the temperature-sensitive antifouling agent is as follows:

[0039] Step (1)

[0040] The halloysite is calcined at 300-1000° C. for 1-3 hours and then ground into powder to obtain heat-activated halloysite; a fluorine-containing silane coupling agent is dissolved in anhydrous toluene, the heat-activated halloysite is added, and the mixture is stirred evenly; the temperature is then raised to 110-130° C., stirred, condensed and refluxed in an anhydrous environment for 6-24 hours, and then cooled to room temperature, filtered and washed with toluene, and the solid residue is dried at 60-100° C. for 6-24 hours, and then crushed and sieved to obtain fluorinated modified halloysite;

[0041] Wherein, the mass ratio of the halloysite to the fluorine-containing silane coupling agent is 1:0.5-3; the ratio of the fluorine-containing silane coupling agent to the anhydrous toluene is 0.01-0.5 mol:1L;

[0042] Step (2)

[0043] The fluorinated modified halloysite is added to an ethanol solution of a temperature-sensitive antifouling agent and mixed evenly to obtain a mixed system; the mixed system is stirred: the mixed system is placed under vacuum conditions and stirred for a first time for 20 to 40 minutes, and then the mixed system is restored to normal pressure conditions and stirred for a second time for 10 to 20 minutes; wherein the stirring process is repeated 2 to 5 times; the stirred mixed system is filtered, washed, freeze-dried, and ground to obtain the fluorinated modified halloysite loaded with the temperature-sensitive antifouling agent.

[0044] The mass ratio of the fluorinated modified halloysite to the temperature-sensitive antifouling agent ethanol solution is 1:10-100, and the mass concentration of the temperature-sensitive antifouling agent in the temperature-sensitive antifouling agent ethanol solution is 0.1-30%.

[0045] The fluorine-containing silane coupling agent is selected from any one or more of heptafluorodecyltriethoxysilane, heptafluorodecyltrimethoxysilane, tridecafluorooctyltriethoxysilane, tridecafluorooctyltrimethoxysilane, nonafluorohexyltrimethoxysilane, and nonafluorohexyltriethoxysilane; the temperature-sensitive antifouling agent is 2-octyl-2H-furan-5-one.

[0046] The present invention also provides the following embodiments and comparative examples:

[0047] 1. The present invention provides the following preparation examples and comparative examples of fluorinated modified halloysite loaded with a temperature-sensitive antifouling agent. The preparation parameters and product loading data are as follows, as shown in Table 1:

[0048] Table 1

[0049]

[0050] In Table 1, the coupling agent loading refers to the mass ratio of the fluorinated silane coupling agent to the fluorinated modified halloysite; the antifouling agent loading refers to the mass ratio of the antifouling agent to the fluorinated modified halloysite loaded with the temperature-sensitive antifouling agent.

[0051] (1) According to the parameters in Table 1, the fluorinated modified halloysite loaded with the temperature-sensitive antifouling agent was prepared in the embodiment. The preparation steps are as follows:

[0052] 1) calcining halloysite at a certain temperature for 2 hours and then grinding it into powder to obtain heat-activated halloysite, adding 3.5 g of the heat-activated halloysite to 100 mL of a 0.05 mol / L anhydrous toluene solution of a fluorinated silane coupling agent, stirring uniformly, then heating to 115° C., stirring and refluxing under condensation in an anhydrous environment for 6 hours, then cooling to room temperature, filtering and washing with toluene three times, and then vacuum drying the solid residue at 80° C. for 6 hours, crushing, and sieving to obtain fluorinated halloysite.

[0053] 2) 3 g of fluorinated halloysite was added to 120 g of an ethanol solution of a thermosensitive antifouling agent (5% mass concentration of the thermosensitive antifouling agent) and mixed uniformly. The mixture was stirred under vacuum conditions for 30 minutes, and then the mixture was returned to normal pressure and stirred for 20 minutes. This cycle was repeated three times. After filtration, washing, freeze-drying, and grinding, the fluorinated halloysite loaded with the thermosensitive antifouling agent was obtained.

[0054] It should be noted that the calcination temperature "-" in Example A1 indicates that no calcination was performed during the preparation process; and no temperature-sensitive antifouling agent was loaded during the preparation process of Comparative Example a1.

[0055] (2) Analyzing the data in Table 1, we can see that:

[0056] The fluorinated halloysite loaded with a temperature-sensitive antifoulant prepared by high-temperature calcination in step 1) of Examples A2-A5 exhibited high coupling agent loading and antifoulant loading rates. The product obtained by not performing high-temperature calcination in step 1) of Example A1 also exhibited high antifoulant loading and coupling agent loading rates. Specifically, Example A5, which employed calcination at 700°C in step 1), exhibited the best coupling agent loading and antifoulant loading rates.

[0057] In the product prepared in Comparative Example a1, the loading amount of the temperature-sensitive antifouling agent is 0.

[0058] 2. The present invention also provides the following examples and comparative examples for preparing coating products, the formulations of which are shown in Table 2 (parts by weight):

[0059] Table 2

[0060]

[0061]

[0062] The raw materials used in the above examples and comparative examples are as follows (the components in the provided examples and comparative examples are all products from the same company and the same series):

[0063] The polydimethylsiloxane-based polyurea resin selected has a polydimethylsiloxy chain content of 85% by mass and a molecular weight Mn of 2000 g / mol.

[0064] The polydimethylsiloxane-based polyurethane resin selected has a polydimethylsiloxy chain content of 85% by mass and a molecular weight Mn of 2000 g / mol.

[0065] The selected temperature-sensitive antifouling agent is 2-octyl-2H-furan-5-one; the selected pigments and fillers are iron oxide red, talc powder and mica powder, with a mass ratio of 1:3:5 and a particle size of 50 μm; the selected additive is fumed silica; the selected solvent is a combination of methyl isobutyl ketone and butyl acetate, with a mass ratio of 1:1.

[0066] The coatings in Table 2 were prepared as follows:

[0067] Step 1: The antifouling agent in Table 2 is mixed with halloysite and part of the solvent and stirred uniformly, and then ultrasonically dispersed in an ice-water bath for 20 minutes to obtain a fluorinated halloysite dispersion loaded with the temperature-sensitive antifouling agent;

[0068] Step 2: Mix the low surface energy resin, additives and another part of the solvent and stir them evenly, then add the pigments and fillers and disperse or grind them at high speed to a fineness of less than 60 μm, filter and obtain a resin powder dispersion;

[0069] Step 3: After mixing the fluorinated modified halloysite dispersion loaded with the temperature-sensitive antifouling agent and the resin powder dispersion, stirring and dispersing them uniformly, and filtering, the temperature-sensitive low surface energy antifouling coating is obtained.

[0070] 3. The test results of the release rate of the antifouling agent of Example B3 and Comparative Example b3 at different temperatures are shown in Table 3:

[0071] Table 3

[0072]

[0073] 4. The test results of the release of the antifouling agent during the gradient heating and cooling process of Example B3 are shown in Table 4:

[0074] Table 4

[0075]

[0076] In Table 3-4, the specific test methods are as follows: The test method of antifouling agent release rate refers to the literature "Preparation and Performance of Natural Product-based Copper-free Self-polishing Antifouling Coatings [J]. China Surface Engineering, 2019, 32(4): 110-111".

[0077] The release rate of the antifouling agent at different temperatures was tested by placing the sample in seawater at different temperatures, performing the antifouling release experiment. The data were averaged over 14-21 days at five different temperatures: 10°C, 15°C, 20°C, 25°C, and 30°C. The data in Table 3 were obtained. The release amount of the antifouling agent during a gradient heating and cooling process was tested by placing the sample in seawater, subjecting the seawater to a gradient heating and cooling process from 10°C to 30°C and then back to 10°C. The release amount of the antifouling agent was measured at five different temperatures: 10°C, 15°C, 20°C, 25°C, and 30°C. The data in Table 4 were obtained.

[0078] The results in Table 3-4 show that:

[0079] Comparative Example b3 has a high antifouling agent release rate at low temperatures (≤ the freezing point of the antifouling agent 22.27°C), and the release rate increases rapidly with increasing temperature. This is because part of the antifouling agent migrates to the coating surface. When the temperature rises, the antifouling agent exists in the form of a liquid and is more easily migrated to the surface and released.

[0080] For the coating prepared in Example B3, the release rate of the antifouling agent is stable at the same temperature, while the release rate of the antifouling agent changes significantly with temperature. The release rate increases with increasing temperature and decreases with decreasing temperature, thus achieving the purpose of controlling the release of the antifouling agent with temperature changes.

[0081] 5. The test results of the performance of Examples B1-B4 and Comparative Examples b1-b4 are shown in Table 5:

[0082] Table 5

[0083]

[0084] In Table 5, the water contact angle of the coating was measured using a contact angle meter. The coating adhesion was determined according to ASTM D4541-09, and the substrate was an epoxy resin board. The antifouling effect was evaluated using the shallow sea immersion test method for antifouling paint samples, which is based on GB / T 5370.

[0085] Comparative Example B4 uses a conventional foul-releasing antifouling coating, specifically a silicone-based antifouling coating without an antifouling agent. Examples B1-B4 and Comparative Examples B1-B3 are applied directly over the epoxy primer, while Comparative Example B4 is applied after applying the matching tie coat over the epoxy primer.

[0086] The results in Table 5 show that:

[0087] Examples B1-B4 were directly applied to the epoxy primer and had higher coating adhesion than Comparative Example b3. This indicates that the use of polydimethylsiloxane-based polyurea resin or polydimethylsiloxane-based polyurethane resin as the coating base resin in the embodiments of the present invention can enhance the bonding performance between the antifouling coating and the epoxy primer. Compared with the direct addition of the antifouling agent (Comparative Example b3), the use of fluorinated halloysite loaded with the antifouling agent in the embodiments of the present invention is more conducive to improving the adhesion between the antifouling coating and the epoxy primer.

[0088] The water contact angles of Examples B1-B4 were large, and they had good antifouling effects.

[0089] The fluorinated halloysite of Comparative Example b1 does not carry an antifouling agent, and its antifouling effect is reduced compared with Example B4.

[0090] The halloysite of Comparative Example b2 was neither fluorinated nor loaded with an antifouling agent, and had the worst antifouling effect.

[0091] Comparative Example b3 directly adds a temperature-sensitive antifouling agent, resulting in low water contact angle and adhesion. In addition, due to the rapid release of the antifouling agent, the antifouling effect is significantly reduced, and the long-term antifouling effect is poor.

[0092] In comparative example b4, the antifouling paint can only be applied after the matching connecting paint is applied. Otherwise, the coating will fall off and become ineffective during the shallow sea hanging board immersion test, and its antifouling effect is average.

[0093] In summary, the temperature-sensitive low surface energy antifouling coating provided by the present invention has at least the following design concepts and beneficial effects:

[0094] (1) The present invention uses polydimethylsiloxane-based polyurea resin or polydimethylsiloxane-based polyurethane resin as the coating matrix resin: the polar urea bond or urethane bond in the resin structure forms hydrogen bonds with the polar groups such as ether bonds and hydroxyl groups of the epoxy primer, so that the coating has good adhesion to the epoxy primer. At the same time, during the evaporation of the solvent, the polydimethylsiloxane chain segments can be enriched on the coating surface; the coating is a single component, and compared with commercial two-component or three-component low surface energy antifouling paints, the single-component coating has the advantages of convenient storage and construction.

[0095] (2) The present invention modifies the surface of fluorinated halloysite with a fluorinated silane coupling agent. The fluorinated silane coupling agent undergoes a grafting reaction and an oligomerization reaction on the surface of the halloysite (condensation reaction occurs between hydrolyzed silanes to form oligomers), so that the surface of the halloysite is enriched with flexible fluorinated chain segments. Under the stress generated by solvent volatilization, the fluorinated halloysite near the surface will be enriched on the coating surface, which effectively reduces the surface free energy of the low-surface coating. The fluorinated halloysite inside the coating loses its migration power after being covered by the fluorinated chain segments and remains in the coating, thereby increasing the cohesive strength of the coating.

[0096] (3) The temperature-sensitive antifouling agent 2-octyl-2H-furan-5-one used in the scheme of the present invention is a new type of non-toxic antifouling compound, and it is loaded on fluorinated halloysite. When the antifouling agent is released, it is first desorbed from the halloysite tube wall, then migrates in the tube cavity, and finally migrates in the polymer molecular chain of the base resin before being released, thereby achieving a sustained release effect.

[0097] The thermosensitive antifouling agent has a long-chain alkyl structure, and the oxygen atoms in the structure have a chemical affinity for urea or amino units, so it prefers to remain in the coating. After immersion in seawater, due to changes in osmotic pressure, as fluorinated halloysite accumulates on the coating surface, the antifouling agent near the surface is preferentially released. The internal antifouling agent gradually migrates to the coating surface and is released. Because the freezing point of the thermosensitive antifouling agent is around 22.27°C, when the temperature is below the freezing point, the antifouling agent is mainly solid, the mobility of the long-chain molecules is weakened, and its release rate slows. When the temperature is above the freezing point, the antifouling agent is liquid, the mobility of the long-chain molecules is enhanced, and the release rate increases, and the release rate increases with increasing temperature.

[0098] In summary, the coating provided by the present invention utilizes a single-component polydimethylsiloxane polyurea resin or polydimethylsiloxane polyurethane resin as a base resin, exhibiting excellent bonding properties with epoxy substrates. Furthermore, the coating utilizes fluorinated halloysite loaded with a novel, non-toxic, temperature-sensitive antifouling agent, effectively slowing the release of the antifouling agent while also allowing the release rate of the antifouling agent to vary with temperature. In particular, in the coating formed by the coating, fluorinated halloysite accumulates on the coating surface, effectively reducing the surface free energy of the coating. Combined with the controlled release of the non-toxic temperature-sensitive antifouling agent, this enhances the antifouling effect under static conditions, achieving the goal of efficient and long-lasting antifouling.

[0099] It should be noted that:

[0100] In this article, “~” is used to indicate a numerical range, and the range indicated by this expression includes two endpoint values.

[0101] In addition to the actual selections embodied in the above specific embodiments, the coating formula includes the following components in parts by weight: 20 to 70 parts of low surface energy resin, 0.1 to 20 parts of fluorinated modified halloysite loaded with temperature-sensitive antifouling agent, 0 to 42 parts of pigment and filler, 0.5 to 5 parts of additive, and 10 to 50 parts of solvent; the above formula range can be adopted in the specific implementation of the present invention, including but not limited to the above embodiment scheme.

[0102] Among them, the low surface energy resin is a polydimethylsiloxane polyurea resin or a polydimethylsiloxane polyurethane resin; in addition to the actual selection embodied in the above specific embodiments, preferably, the mass content of the polydimethylsiloxane segment in the low surface energy resin is 50-95%, and the molecular weight Mn of the polydimethylsiloxane segment is 1000-6000 g / mol. When the present invention is implemented, it is feasible to use low surface energy resins within the above characteristic parameter ranges, including but not limited to the above embodiment schemes.

[0103] In addition to the actual selections embodied in the above specific embodiments, preferably, the color filler includes a pigment and a filler; wherein the pigment is selected from a mixture of any one or more of iron oxide black, iron oxide red, iron oxide yellow, carbon black, toluidine red, phthalocyanine blue and phthalocyanine green, and the filler is selected from a mixture of any one or more of titanium dioxide, dolomite powder, talc powder and mica powder, including but not limited to the actual selections embodied in the above embodiments.

[0104] In addition to the actual selections embodied in the above specific embodiments, preferably, the auxiliary agent is a mixture of any one or more of polyamide wax, organic bentonite, fumed silica, and hydrogenated castor oil, including but not limited to the actual selections embodied in the above embodiments.

[0105] In addition to the actual selections embodied in the above specific embodiments, preferably, the solvent is selected from any one or more mixtures of methyl isobutyl ketone, butanone, butyl acetate, xylene, n-butanol, and propylene glycol methyl ether acetate, including but not limited to the actual selections embodied in the above embodiments.

[0106] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A temperature-sensitive low surface energy antifouling coating, characterized by: The invention comprises the following components in parts by weight: 20 to 70 parts of low surface energy resin, 0.1 to 20 parts of fluorinated modified halloysite loaded with temperature-sensitive antifouling agent, 0 to 45 parts of pigment and filler, 0.5 to 5 parts of auxiliary agent, and 10 to 50 parts of solvent; Wherein, the low surface energy resin is a polydimethylsiloxane-based polyurea resin or a polydimethylsiloxane-based polyurethane resin; The fluorinated modified halloysite loaded with a temperature-sensitive antifouling agent is prepared by adding the fluorinated modified halloysite to an ethanol solution of the temperature-sensitive antifouling agent, mixing the mixture, and then filtering, washing, and freeze-drying the mixture in sequence; wherein the temperature-sensitive antifouling agent is 2-octyl-2H-furan-5-one.

2. The temperature-sensitive low surface energy antifouling coating according to claim 1, characterized in that: The preparation process of the fluorinated modified halloysite loaded with the temperature-sensitive antifouling agent is as follows: The halloysite is calcined at 300-1000° C. for 1-3 hours and then ground into powder to obtain heat-activated halloysite; a fluorine-containing silane coupling agent is dissolved in anhydrous toluene, the heat-activated halloysite is added, and the mixture is stirred evenly; the temperature is then raised to 110-130° C., stirred, condensed and refluxed in an anhydrous environment for 6-24 hours, and then cooled to room temperature, filtered and washed with toluene, and the solid residue is dried at 60-100° C. for 6-24 hours, and then crushed and sieved to obtain fluorinated modified halloysite; adding the fluorinated modified halloysite to the temperature-sensitive antifouling agent ethanol solution and mixing them uniformly to obtain a mixed system; Stirring the mixed system: placing the mixed system under vacuum conditions, stirring for a first time for 20 to 40 minutes, then returning the mixed system to normal pressure conditions, and stirring for a second time for 10 to 20 minutes; wherein the stirring process is repeated 2 to 5 times; The stirred mixed system is filtered, washed, freeze-dried and ground to obtain the fluorinated modified halloysite loaded with the temperature-sensitive antifouling agent.

3. The temperature-sensitive low surface energy antifouling coating according to claim 2, characterized in that: The mass ratio of the halloysite to the fluorine-containing silane coupling agent is 1:0.5-3; the ratio of the fluorine-containing silane coupling agent to the anhydrous toluene is 0.01-0.5 mol:1L; The mass ratio of the fluorinated modified halloysite to the temperature-sensitive antifouling agent ethanol solution is 1:10-100, wherein the mass concentration of the temperature-sensitive antifouling agent in the temperature-sensitive antifouling agent ethanol solution is 0.1-30%.

4. The temperature-sensitive low surface energy antifouling coating according to claim 2, characterized in that: The fluorine-containing silane coupling agent is a mixture of any one or more of heptafluorodecyltriethoxysilane, heptafluorodecyltrimethoxysilane, tridecafluorooctyltriethoxysilane, tridecafluorooctyltrimethoxysilane, nonafluorohexyltrimethoxysilane and nonafluorohexyltriethoxysilane.

5. The temperature-sensitive low surface energy antifouling coating according to claim 1, characterized in that: The mass content of the polydimethylsiloxy chain segment in the low surface energy resin is 50-95%, and the molecular weight Mn of the polydimethylsiloxy chain segment is 1000-6000 g / mol.

6. The temperature-sensitive low surface energy antifouling coating according to claim 1, characterized in that: The color filler includes pigments and fillers; the pigment is a mixture of any one or more of iron oxide black, iron oxide red, iron oxide yellow, carbon black, toluidine red, phthalocyanine blue and phthalocyanine green, and the filler is a mixture of any one or more of titanium dioxide, dolomite powder, talc powder and mica powder.

7. The temperature-sensitive low surface energy antifouling coating according to claim 1, characterized in that: The particle size of the pigment and filler is ≤50 μm.

8. The temperature-sensitive low surface energy antifouling coating according to claim 1, characterized in that: The auxiliary agent is a mixture of any one or more of polyamide wax, organic bentonite, fumed silica, and hydrogenated castor oil; And / or, the solvent is a mixture of any one or more of methyl isobutyl ketone, butanone, butyl acetate, xylene, n-butanol, and propylene glycol methyl ether acetate.

9. A method for preparing a temperature-sensitive low surface energy antifouling coating according to any one of claims 1 to 8, characterized in that: The following steps are involved: The fluorinated modified halloysite loaded with the temperature-sensitive antifouling agent and a portion of the solvent are mixed and stirred uniformly, and then ultrasonically dispersed in an ice-water bath for 10 to 30 minutes to obtain a fluorinated modified halloysite dispersion loaded with the temperature-sensitive antifouling agent; Mix the low surface energy resin, additives and another part of the solvent and stir them evenly, then add pigments and fillers and disperse or grind them at high speed to a fineness of less than 60 μm, filter and obtain a resin powder dispersion; The fluorinated modified halloysite dispersion loaded with the temperature-sensitive antifouling agent and the resin powder dispersion are mixed, stirred and dispersed evenly, and filtered to obtain the temperature-sensitive low surface energy antifouling coating.

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