A temporary antifouling paint which can be self-stripped and a method for preparing the same

Abstract

The present application belongs to the technical field of chemical materials, and particularly relates to a temporary antifouling paint capable of self-shedding and peeling and a preparation method thereof. By matching the ratio of epoxy resin and zinc acrylate resin in the paint formula, the paint has good matching adhesion performance with the acrylic antifouling paint in the dry state. Meanwhile, when the coating is immersed in water and absorbs water, and then is dried again, the coating cracks due to the high brittleness, and peels off from the surface of the lower main antifouling coating. Or after the conventional cleaning operation such as washing with normal pressure fresh water, the coating can be completely shed and peeled. The antifouling paint can be applied in the field of ship building or maintenance, can reduce the cost during the coating construction, improve the actual service life and antifouling effect of the antifouling paint, and has good economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of chemical materials technology, and in particular relates to a temporary antifouling coating that can be detached and peeled off on its own and its preparation method. Background Technology

[0002] Marine fouling organisms are biological species that attach to and grow on man-made structures such as ships. They mainly include barnacles, oysters, mussels, seaweed, and marine bacteria, posing a significant threat to these structures. Taking large ocean-going vessels as an example, once fouling organisms attach, the amount can reach 150 kg / m² within six months, resulting in approximately 6,000 tons of fouling on a 40,000 square meter underwater surface. This massive amount of fouling not only increases the ship's weight but also alters its streamlined structure, increasing drag and significantly boosting fuel consumption. Furthermore, fouling organisms degrade maneuverability, reduce propeller efficiency, increase noise, and interfere with sonar, forcing ships to dock prematurely for cleaning and incurring substantial maintenance costs, severely impacting their service life and combat effectiveness. Currently, methods for preventing fouling organism attachment mainly include mechanical removal, seawater electrolysis, and antifouling coatings. Antifouling coatings are the most convenient and widely used method. Therefore, marine antifouling materials have become a research hotspot for research institutions both domestically and internationally.

[0003] Currently, in the mainstream shipbuilding and repair processes of major shipyards in my country, there is a process where ships are launched from dry dock and moored at the wharf for outfitting operations. The outfitting process can take a considerable amount of time, ranging from a few days to several months, and even more than six months. After outfitting is completed, some ships, due to various issues, will return to the dry dock or slipway for repair or repair work. This secondary outboard docking process affects the actual performance of the antifouling coating, resulting in a shortened antifouling period and poorer interlayer adhesion between the final sprayed coating and the original coating.

[0004] The secondary application process can negatively impact the already applied antifouling coating. This is mainly reflected in the following two aspects:

[0005] First, the antifouling coating undergoes an ion exchange process in water, releasing antifouling agents. Since there is no water flow to wash the ship during outfitting in the water, the surface coating that has already undergone ion exchange and released antifouling agents cannot dissolve in the water through self-polishing. As a result, the antifouling ability of this surface antifouling paint decreases after re-entry into the water, and the probability of fouling organisms attaching increases significantly. When fouling organisms attach, the attached fouling organisms will significantly affect the release effect of the antifouling agents of subsequent coatings, thus affecting the overall antifouling effect.

[0006] After the second and third discharges, the antifouling coating has a large amount of dirt on its surface. If the ship plans to reapply the first-level antifouling coating below the waterline, the coating surface needs to be cleaned, generally by rinsing with fresh water at atmospheric pressure. After rinsing, a new first-level antifouling paint is applied. However, even with rinsing with fresh water at atmospheric pressure, the adhesion between the coating and the newly applied coating cannot achieve the same effect as the original dry coating in a non-water-immersed environment. It is frequently observed at shipbuilding and repair sites that after a ship discharges, large areas of the surface antifouling coating peel off. The vast majority of the peeled coating is the first-level antifouling paint that was reapplied after a second discharge. Specifically... Figure 1 As shown.

[0007] Patent CN201810439493.7 discloses an environmentally friendly water-based paint for temporary protection of copper-containing antifouling coatings. It is water-soluble and extends the overall antifouling period of the coating. However, this patented product only achieves the extension of the overall antifouling period by inhibiting the release of the antifouling agent from the main antifouling coating. It does not address the handling of this temporary protective coating in the event of secondary discharge from the ship. Nor does it explain or propose how to address the adverse effects of secondary discharge on antifouling coatings during current shipbuilding and repair processes in my country. Summary of the Invention

[0008] To address the problem of antifouling paint loss during secondary discharge from ships, as mentioned in the background section, this invention provides a self-removing temporary antifouling coating, comprising the following components:

[0009] Zinc acrylate resin, bisphenol A epoxy resin, acrylic resin, antifouling agents, fillers and pigments, additives, solvents.

[0010] The weight ratio of bisphenol A epoxy resin to acrylic resin is 2-3:1.

[0011] The total mass of zinc acrylate resin and acrylic resin is in a weight ratio of 1:1-1.5 to bisphenol A epoxy resin.

[0012] The bisphenol A epoxy resin has a number average molecular weight of 5000-6000 g / mol and an epoxy equivalent of 180-250 g / eq. The zinc acrylate resin has a zinc content of 8%-12% of the resin weight. The acrylic resin has a number average molecular weight of 2000-4000 g / mol and an acid value of 3-5 mg·KOH / g.

[0013] In some embodiments, the components further include the following parts by weight:

[0014] 5-15 parts of zinc acrylate resin

[0015] 15-25 parts of bisphenol A type epoxy resin

[0016] 7-13 parts acrylic resin

[0017] 15-40 parts antifouling agent

[0018] 5-30 parts filler and pigment

[0019] 1-3 parts of auxiliary agent

[0020] Solvent 10-25 parts.

[0021] In some embodiments, the antifouling agent is one or two of cuprous oxide, cuprous thiocyanate, copper pyrithione, zinc pyrithione, zinc mancozeb, bromopyrrolidone, and isothiazolinone.

[0022] In some embodiments, the pigment further includes at least one of extender pigments and coloring pigments.

[0023] In some embodiments, the coloring pigment is further selected from one or more of titanium dioxide, iron oxide red, iron oxide black, iron oxide yellow, ultramarine, carbon black, scarlet powder, toluidine red, chrome yellow, phthalocyanine blue, and phthalocyanine green.

[0024] In some embodiments, the extender pigments may be one or more of the following: talc, precipitated barium sulfate, mica powder, wollastonite powder, light calcium carbonate, kaolin, zinc oxide, quartz powder, and feldspar powder.

[0025] In some embodiments, the additive is further described as an anti-settling agent, which is one or two of hydrogenated castor oil, polyamide wax, organobentonite, fumed silica, polyethylene wax, and aluminum stearate.

[0026] In some embodiments, the solvent is further selected from one or more of xylene, toluene, ethylbenzene, hexane, heptane, cyclohexane, butanol, isopropanol, ethylene glycol monomethyl ether, butyl acetate, and ethylene glycol methyl ether acetate.

[0027] The present invention also provides a method for preparing any of the temporary antifouling coatings described above, comprising the following steps:

[0028] Step a: Add zinc acrylate resin, bisphenol A epoxy resin and acrylic resin into the mixing cylinder and disperse them evenly at high speed, with a rotation speed of 1000-1500 r / min;

[0029] Step b: Add antifouling agent (except cuprous oxide), pigment, additives and solvent and then sand mill;

[0030] Step c: Grind for 1 hour to a fineness of less than 80μm. At this time, add cuprous oxide and disperse it evenly at high speed. The rotation speed is 1000-1500 r / min. The material discharged is a temporary antifouling coating that can be peeled off by itself.

[0031] The principles and beneficial effects of this invention are as follows:

[0032] To address the problems in the prior art, this invention creatively provides a temporary antifouling coating that can be self-detached and peeled off. Through a combination of bisphenol A type epoxy resin, acrylic resin and zinc acrylate resin, the coating can be self-detached and peeled off after the secondary discharge of water from the ship to remove water, or the coating can be peeled off by rinsing with fresh water at normal pressure. The bisphenol A epoxy resin and acrylic resin are combined with a number average molecular weight of 5000-6000 g / mol and 2000-4000 g / mol, respectively. The epoxy equivalent of the bisphenol A epoxy resin is 180-250 g / eq. This design ensures that the coating becomes more brittle after the secondary unloading and dehydration of the coating, reaching the point of cracking. The acid value of the acrylic resin needs to be controlled at 3-5 mg·KOH / g to provide flexibility to the coating, ensuring that the design of the bisphenol A epoxy resin and acrylic resin will not detach from the hull in the water when the ship is unloaded and entered into the water. The zinc acrylate resin needs to have a zinc content of 8%-12% of the resin weight, has a fast hydrolysis rate, and can play an antifouling role when the ship is unloaded and entered into the water. It has a particularly good static antifouling effect to adapt to the actual seawater environment and dock outfitting environment. It can also accelerate the dehydration of the bisphenol A epoxy resin and acrylic resin after the secondary unloading, so that the coating can achieve the effect of automatic cracking and peeling.

[0033] The self-removable temporary antifouling coating provided by this invention, in practical use, involves first applying the existing main antifouling coating to the hull, and then applying the temporary antifouling coating of this invention after it has dried. When the ship is docked for outfitting, because the zinc content of the acrylate zinc resin in the temporary antifouling coating is higher than that in the existing main antifouling coating, an ion concentration difference is formed between the aquatic environment and the underlying main antifouling coating. This significantly inhibits the seepage of antifouling agent from the main antifouling coating, reduces the amount of antifouling agent seeping out of the main antifouling coating, protects the main antifouling coating from antifouling agent consumption during outfitting, and improves the actual effectiveness and antifouling effect of the main antifouling coating.

[0034] Through the above-mentioned ingenious design, this invention not only ensures the antifouling effect when ships are docked at the pier for outfitting, but also causes the ships to shrink and crack significantly after secondary discharge, so that they peel off from the underlying main antifouling coating on their own. Then, by performing a conventional atmospheric pressure fresh water cleaning operation, the entire temporary antifouling coating can be easily removed. Attached Figure Description

[0035] Figure 1 The image shows the cracking and peeling of a first-layer protective coating that has been reapplied in the existing technology.

[0036] Figure 2 This document shows the self-cracking and peeling of the temporary protective coating in this case. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. The technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be noted that all terms used in this invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and should not be construed as limiting the invention; it should be further understood that the terms used in this invention should be understood to have the same meaning as those in the context of this specification and in the relevant field, and should not be understood in an idealized or overly formal sense, except as expressly defined in this invention.

[0039] The present invention provides the following preferred embodiments of a temporary antifouling coating that can be detached and peeled off on its own.

[0040] Example 1

[0041] Preparation of coating: 8 parts by weight of zinc acrylate resin, zinc content (8%); 16 parts by weight of bisphenol A epoxy resin, number average molecular weight 5000 g / mol, epoxy equivalent 180 g / eq; 8 parts by weight of acrylic resin, number average molecular weight 2000 g / mol, acid value 3.5 mg·KOH / g; 20 parts by weight of cuprous oxide antifouling agent; 2 parts by weight of copper pyridinethione; 25 parts by weight of filler and pigment; 1 part by weight of additive; 20 parts by weight of solvent.

[0042] Example 2

[0043] Preparation of coating: 10 parts by weight of zinc acrylate resin, zinc content (12%); 20 parts by weight of bisphenol A epoxy resin, number average molecular weight 6000 g / mol, epoxy equivalent 220 g / eq; 10 parts by weight of acrylic resin, number average molecular weight 3000 g / mol, acid value 4.3 mg·KOH / g; 15 parts by weight of cuprous oxide antifouling agent; 3 parts by weight of copper pyridinethione; 20 parts by weight of filler and pigment; 2 parts by weight of additives; 20 parts by weight of solvent.

[0044] Example 3

[0045] Preparation of the coating: 10 parts by weight of zinc acrylate resin, zinc content (10%); 24 parts by weight of bisphenol A epoxy resin, number average molecular weight 5000 g / mol, epoxy equivalent 200 g / eq; 12 parts by weight of acrylic resin, number average molecular weight 2500 g / mol, acid value 3.5 mg·KOH / g; 24 parts by weight of cuprous oxide antifouling agent; 2 parts by weight of copper pyridinethione; 15 parts by weight of fillers and pigments; 3 parts by weight of additives; and 10 parts by weight of solvent.

[0046] In the above embodiments, the fillers and pigments can be selected according to existing needs; the additives and solvents are hydrogenated castor oil and xylene, respectively. Alternatively, according to other requirements, the additives can be one or two of hydrogenated castor oil, polyamide wax, organobentonite, fumed silica, polyethylene wax, and aluminum stearate, and the solvents can be one or more of xylene, toluene, ethylbenzene, hexane, heptane, cyclohexane, butanol, isopropanol, ethylene glycol monomethyl ether, butyl acetate, and ethylene glycol methyl ether acetate.

[0047] The preparation method of the above embodiment is as follows: Raw materials are fed into a grinding cylinder, dispersed at high speed until uniform, and antifouling agent (except cuprous oxide), pigment, additives, and solvent are added for sand milling; the fineness is less than 80 μm after sand milling for 1 hour. To prevent cuprous oxide from oxidizing and reducing antifouling performance, cuprous oxide is added at this time, dispersed at high speed until uniform, viscosity is adjusted, and then discharged and packaged.

[0048] In Example 1, the temporary protective coating exhibited self-cracking and peeling after 5 days of normal sun exposure, as follows: Figure 2 As shown. By Figure 2 and Figure 1 The comparison shows that the temporary protective coating is more brittle and cracked, and has a better degree of separation from the base coat, exhibiting good self-cracking and peeling effects.

[0049] Comparative Example 1

[0050] Compared with Example 1, the zinc acrylate resin was 10 parts by weight, the ratio of bisphenol A epoxy resin to acrylic resin by weight was 1:1, the ratio of the total mass of zinc acrylate resin and acrylic resin to the weight of bisphenol A epoxy resin was 1:2, and the other conditions remained the same as in Example 1.

[0051] Comparative Example 2

[0052] Compared with Example 1, the bisphenol A type epoxy resin has a number average molecular weight of 3000 g / mol and an epoxy equivalent of 100 g / eq, the acrylic resin has a number average molecular weight of 1500 g / mol, and the other conditions are the same as in Example 1.

[0053] Comparative Example 3

[0054] Compared with Example 1, the bisphenol A type epoxy resin has a number average molecular weight of 8000 g / mol and an epoxy equivalent of 300 g / eq, and the acrylic resin has a number average molecular weight of 5000 g / mol. The other conditions are the same as those in Example 1.

[0055] Comparative Example 4

[0056] Compared to Example 1, the zinc content in the zinc acrylate resin is 5%, while the other conditions remain the same as in Example 1.

[0057] The above embodiments and comparative examples were subjected to corresponding tests. The test method (standard) was as follows: observation and visual inspection. The above conditions were normal sunlight exposure, no rain, and a temperature of 25℃-35℃. The main antifouling paint used was consistent with existing conventional acrylic zinc resin antifouling paint, and the zinc content of the acrylic zinc resin accounted for 5%-6% of the resin weight. Among them, the degree of temporary paint peeling was the percentage of peeled paint area to the total area.

[0058] The results are shown in the table below:

[0059] Table 1

[0060]

[0061] The antifouling effect test was conducted by applying the main antifouling paint and temporary antifouling paint to Examples 4 and Comparative Example 4, simulating the environment shown in Table 1, and then conducting an antifouling test on the samples after completely removing the temporary antifouling paint. The scoring criteria were based on the national standard GB / T 5370-2007 "Antifouling Paint Sample Shallow Sea Immersion Test Method". The higher the score, the better the antifouling performance.

[0062] The above experimental tests and comparisons show that each component and its corresponding parameters affect the performance of the product to varying degrees. In particular, the three embodiments, by specifying the weight ratios of the core components—zinc acrylate resin, bisphenol A epoxy resin, and acrylic resin—demonstrate that when used within the given weight ratios, they effectively prevent fouling and peeling. The comparative test results also show that exceeding the given weight ratios, whether too high or too low, fails to effectively protect the main antifouling paint. Furthermore, the selection of number-average molecular weight, acid value, epoxy equivalent, and zinc content in the zinc acrylate resin also plays a crucial role. Therefore, only by using components with appropriate parameters can the desired effect be achieved.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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 self-removing, temporary antifouling coating, characterized in that, It includes the following components: zinc acrylate resin, bisphenol A epoxy resin, acrylic resin, antifouling agent, filler and pigment, additives, and solvent; The weight ratio of bisphenol A type epoxy resin to acrylic resin is 2-3:

1. ， The total mass ratio of the zinc acrylate resin and acrylic resin to the weight ratio of bisphenol A epoxy resin is 1:1-1.

5. ； The bisphenol A type epoxy resin has a number average molecular weight of 5000-6000 g / mol and an epoxy equivalent of 180-250 g / eq. The zinc content of the zinc acrylate resin accounts for 8%-12% of the resin weight. The acrylic resin has a number average molecular weight of 2000-4000 g / mol and an acid value of 3-5 mg·KOH / g.

2. The self-removing temporary antifouling coating according to claim 1, characterized in that, It includes the following components in parts by weight: 5-15 parts zinc acrylate resin, 15-25 parts bisphenol A epoxy resin, 7-13 parts acrylic resin, 15-40 parts antifouling agent, 5-30 parts filler and pigment, 1-3 parts additives, and 10-25 parts solvent.

3. The self-removing temporary antifouling coating according to claim 1, characterized in that, The antifouling agent is one or two of cuprous oxide, cuprous thiocyanate, copper pyridinethione, zinc pyridinethione, zinc mancozeb, bromopyrrolidone, and isothiazolinone.

4. The self-removing temporary antifouling coating according to claim 1, characterized in that, The pigments include at least one of extender pigments and coloring pigments.

5. The self-removing temporary antifouling coating according to claim 4, characterized in that: The coloring pigment is one or more of the following: titanium dioxide, iron oxide red, iron oxide black, iron oxide yellow, ultramarine, carbon black, scarlet powder, toluidine red, chrome yellow, phthalocyanine blue, and phthalocyanine green.

6. The self-removing temporary antifouling coating according to claim 4, characterized in that: The pigments are one or more of the following: talc, precipitated barium sulfate, mica powder, wollastonite powder, light calcium carbonate, kaolin, zinc oxide, quartz powder, and feldspar powder.

7. The self-removing temporary antifouling coating according to claim 1, characterized in that: The additive is an anti-settling agent, which is one or two of hydrogenated castor oil, polyamide wax, organobentonite, fumed silica, polyethylene wax, and aluminum stearate.

8. The self-removing temporary antifouling coating according to claim 7, characterized in that: The solvent is one or more of xylene, toluene, ethylbenzene, hexane, heptane, cyclohexane, butanol, isopropanol, ethylene glycol monomethyl ether, butyl acetate, and ethylene glycol methyl ether acetate.

9. A method for preparing a self-removing, temporary antifouling coating according to any one of claims 1 to 8, characterized in that, Includes the following steps: Step a: Add zinc acrylate resin, bisphenol A epoxy resin and acrylic resin into the mixing cylinder and disperse them evenly at high speed, with a rotation speed of 1000-1500 r / min; Step b: Add antifouling agents, pigments, additives and solvents (excluding cuprous oxide) and perform sand milling; Step c: Grind for 1 hour to a fineness of less than 80μm. At this time, add cuprous oxide and disperse it evenly at high speed. The rotation speed is 1000-1500 r / min. The material discharged is a temporary antifouling coating that can be peeled off by itself.

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