Hydrolytic linear self-polishing antifouling coating and preparation method thereof

Abstract

The present application relates to the technical field of paint, in particular to a hydrolytic linear self-polishing antifouling paint and a preparation method thereof.The linear self-polishing resin system is obtained by compounding ion exchange resin, silane ester resin and additive A in a certain proportion, and is applied to the antifouling paint, so that not only the linear self-polishing antifouling paint can be obtained, but also the unstable hydrolysis of the combination of the ion exchange resin and the silane ester resin during the storage process in the storage tank can be prevented.The linear self-polishing property provided by the present application can greatly prolong the antifouling period of the paint, reduce the roughness of the coating surface and reduce fuel consumption.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a hydrolytic linear self-polishing antifouling coating and its preparation method. Background Technology

[0002] Currently, the most widely used hydrolytic self-polishing antifouling paints generally use two resins with different hydrolysis mechanisms as film-forming substances.

[0003] One type is the ion-exchange self-polishing resin represented by zinc acrylate and copper acrylate; the other type is the main (side) chain degradation or main-side chain bilysis self-polishing resin based on the copolymerization of acrylate or methacrylate, silane acrylate and lactone.

[0004] Since organotin antifouling paints were completely banned by the IMO, mainstream self-polishing antifouling paints currently use zinc acrylate, copper acrylate, and (meth)acrylate silane ester as base resins, and cuprous oxide, zinc oxide, CuPT, ZnPT, zineb, brominated pyrrolidone, and DCOIT as biocides. Antifouling paints using ion-exchange resins, i.e., zinc acrylate or copper acrylate resins, as the base polishing resin generally have an antifouling life of 3 to 5 years; while antifouling paints using (meth)acrylate silane ester resin as the base polishing resin can achieve an antifouling life of 5 years, but this requires a certain ship speed and the effect is not ideal in the early stages of coating service.

[0005] Zinc acrylate / copper resin hydrolyzes in seawater via ionic bonds based on ion exchange, while (meth)acrylate methyl silane ester resin hydrolyzes via covalent bonds. The hydrolysis rates of the two are fundamentally different. The hydrolysis rate of zinc acrylate / copper resin, which hydrolyzes via ionic bonds, is faster than that of (meth)acrylate methyl silane ester, which hydrolyzes via covalent bonds. Consequently, antifouling paints using zinc acrylate as a base polishing resin also have a faster polishing rate than those using (meth)acrylate. Therefore, the antifouling effect of zinc acrylate / copper resin is shorter than that of (meth)acrylate methyl silane ester resin, often only reaching 3 years. Conversely, the latter, due to covalent bond hydrolysis, has a slower initial hydrolysis rate, resulting in less than ideal early antifouling performance in low-speed applications.

[0006] CN 116396684 A discloses a marine antifouling coating, published on July 7, 2023. It describes a method using zinc acrylate resin, main-chain degraded silane acrylate resin, and an antifouling agent to obtain a coating with high adhesion, good self-polishing properties, and excellent antifouling performance. However, in this technical solution, the combined use of zinc acrylate resin and main-chain degraded silane acrylate resin is not conducive to in-tank storage. During storage, the coating is prone to instability issues such as hydrolysis, leading to a reduction in the coating's self-polishing properties and excellent antifouling performance, or even gelling within the tank. Summary of the Invention

[0007] To address the shortcomings of the prior art mentioned in the background section, a hydrolytic linear self-polishing antifouling coating is provided, comprising the following components:

[0008] Ion exchange resins, silane ester resins, solvents, thixotropic agents, plasticizers, biocides, pigments, fillers, and additives A;

[0009] Wherein, the auxiliary agent A is one or a combination of two of ethyl silicate and carbodiimide compounds;

[0010] The weight ratio of ion-exchange resin, silane ester resin and additive A is 5-35:10-20:0-1.

[0011] In some embodiments, the raw materials further include the following parts by weight:

[0012]

[0013]

[0014] In some embodiments, the ion-exchange resin is one or a combination of zinc acrylate and copper acrylate resins.

[0015] In some embodiments, the solvent is further selected from xylene, butyl acetate, ethyl acetate, MIBK, cyclohexanone, methyl ethyl ketone, and methyl isobutyl ketone, or a combination of multiple thereof.

[0016] In some embodiments, the thixotropic agent is one or a combination of two of fumed silica, hydrogenated castor oil, organobentonite, and polyamide wax; the plasticizer is any one or a combination of 42#, 52#, and 70# chlorinated paraffin.

[0017] In some embodiments, the biocide is further comprising one or more combinations of cuprous oxide, zinc oxide, CuPT, ZnPT, zineb, brominated pyrrolidone, and DCOIT.

[0018] In some embodiments, the silane ester resin is further comprising silane acrylate and silane methacrylate based on side-chain degradation or main-chain-side-chain bilysis technology.

[0019] In some embodiments, the pigments and fillers are further selected from one or more of titanium dioxide, iron oxide red, iron oxide yellow, iron oxide black, talc powder, mica powder, wollastonite powder, feldspar powder, barite powder, gypsum powder, and kaolin.

[0020] In some embodiments, when the additive A is a combination of ethyl silicate and carbodiimide compounds, the weight ratio of ethyl silicate to carbodiimide compounds is (1-3):(0.5-1).

[0021] The present invention also provides a method for preparing a hydrolytic linear self-polishing antifouling coating according to any of the above-described methods, comprising the following steps:

[0022] Step A: Add ion exchange resin, solvent and plasticizer to the mixing tank under medium speed stirring, then add thixotropic agent, and disperse at medium speed until gelation is achieved. The stirring speed is 600-1000 r / min.

[0023] Step B: Add biocides and pigments / fillers into the mixing tank under high-speed dispersion, and disperse at high speed until the fineness meets the requirements. The high-speed stirring speed is 1000-1500 r / min.

[0024] Step C: Add silane ester resin and additive A under medium-speed stirring, and disperse at medium speed for 15 minutes, wherein the stirring speed is 600-1000 r / min;

[0025] Step D: Package the obtained paint to obtain the finished antifouling paint.

[0026] The principles and beneficial effects of this invention are as follows:

[0027] This invention obtains a linear self-polishing resin system by compounding ion-exchange resin, silane ester resin, and additive A in a certain proportion. When applied to antifouling paints, it not only produces linear self-polishing antifouling paint but also prevents the combination of ion-exchange resin and silane ester resin from hydrolyzing and cross-linking even in the presence of trace amounts of water, thus preventing the paint from gelling during storage. During the combination of ethyl silicate, ion-exchange resin, and silane ester resin, ethyl silicate preferentially reacts with water and hydrolyzes, thereby protecting the silane ester resin from further hydrolysis and cross-linking. Furthermore, during the combination of carbodiimide and ion-exchange resin, it reacts with the carboxyl groups generated during hydrolysis to form urea compounds, effectively inhibiting further hydrolysis of the ester groups. Furthermore, the combination of carbodiimides and ethyl silicate, when used in conjunction with ion-exchange resins and silane ester resins, not only protects the silane ester resin from hydrolysis by sacrificing ethyl silicate, but also ensures the timely elimination of carboxyl groups after ethyl silicate hydrolysis, thereby inhibiting cross-linking reactions and reducing the risk of in-tank gelation. Through this principle, the synergistic effect between the ion-exchange resin, silane ester resin, and additive A results in a coating with a linear self-polishing effect and stable storage performance. This linear self-polishing characteristic significantly extends the antifouling period of the coating, reduces surface roughness, and decreases fuel consumption. Detailed Implementation

[0028] 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 designed 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] 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.

[0030] The present invention provides the following preferred embodiments of a hydrolytic linear self-polishing antifouling coating.

[0031] Table 1

[0032]

[0033] In Examples 1-3:

[0034] The ion exchange resin used is zinc acrylate resin;

[0035] The solvent system is a combination of trimethylbenzene and n-butanol in a weight ratio of 1:2;

[0036] The thixotropic agent is a combination of organobentonite and hydrogenated castor oil in a weight ratio of 3:2.

[0037] The plasticizer is 52# chlorinated paraffin;

[0038] The biocid is a combination of cuprous oxide, zinc mancozeb and copper pyrithione in a weight ratio of 10:1:1.

[0039] The resin is a silane ester resin with a main side chain of dihydromethacrylate silane ester resin; the pigment and filler is iron oxide red.

[0040] In Example 1, additive A was tetraethyl orthosilicate; in Example 2, it was a carbodiimide compound; in Example 3, additive A was a mixture of tetraethyl orthosilicate and a carbodiimide compound in a 3:1 ratio.

[0041] The present invention also provides the following comparative examples:

[0042] Comparative Example 1: Self-polishing antifouling coating obtained using only ion exchange resin;

[0043] Comparative Example 2: A self-polishing antifouling coating obtained using silane ester resin and additive A, with other conditions the same as in Example 1;

[0044] Comparative Example 3: Compared with Example 1, no additive A was added, and other conditions were the same as in Example 1;

[0045] Comparative Example 4: Compared with Example 3, no additive A was added, and other conditions were the same as in Example 3.

[0046] After thoroughly mixing the samples, the coating was applied to a sample pre-coated with primer and bonding paint. After the sample was fully dried, performance tests were conducted, and the results were compared with those of an antifouling paint without linear self-polishing technology. The test results are shown in Table 2.

[0047] Table 2

[0048]

[0049]

[0050] According to the national standard GB / T 31411 "Method for Determination of Abrasion Rate of Marine Antifouling Paint", abrasion rate tests were conducted on Examples 1, 2, and 3, and Comparative Examples 1 and 2 using a rotary drum dynamic simulation test device and a laser thickness gauge. The results showed that, except for Cycle I, which was abnormally high due to the swelling and reduction of the antifouling paint film, the abrasion rates of all Examples 1, 2, and 3, and Comparative Examples 1 and 2, changed according to a certain pattern in Cycles II to X. Specifically, the abrasion rates of Examples 1-3 were maintained at a reasonable level of 5 μm / M for several cycles in the later stages of the cycle. In contrast, the abrasion rate of Comparative Example 1 was initially high, but decreased rapidly as the cycle progressed; the abrasion rate of Comparative Example 2 was initially low, but gradually increased as the cycle progressed. Clearly, the abrasion rates of Examples 1-3 are beneficial for long-term polishing of the antifouling paint film, while the rapid decrease in polishing rate in the later stages of Comparative Example 1 would lead to antifouling failure; similarly, insufficient polishing in the early stages of Comparative Example 2 would also lead to early antifouling failure. Comparative Examples 3 and 4 did not contain the key additive A, so the coatings themselves tended to crosslink. After being made into coatings, they were not easily hydrolyzed, and the abrasion rate remained low, which could not meet the reasonable polishing level of 5μm / M.

[0051] By testing the initial viscosity of Examples 1-3 and Comparative Examples 1-4 and tracking the viscosity change trend each month thereafter, the results showed that the viscosity of Examples 1-3 and Comparative Examples 1 and 2 increased slowly over time. Although the viscosity increased after 5 months, it did not affect construction and application. However, the viscosity of Comparative Examples 3 and 4, which did not use additive A, increased rapidly, reaching the upper limit of the viscometer of 20,000 mPa·s only after two months. Moreover, the coating became gelled and could not be used.

[0052] 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 hydrolytic linear self-polishing antifouling coating, characterized in that, Including the following parts by weight of raw materials: Ion exchange resin 5~35 Silane ester resin 10~20 Solvent 5~15 Thixotropic agent 0.2~2 Plasticizer 2~8 Biological killer 30~60 Pigment and filler 5~15 Additive A 0.3~1; Wherein, the auxiliary agent A is one or a combination of two of ethyl silicate and carbodiimide compounds; The weight ratio of ion-exchange resin, silane ester resin and additive A is 5~35:10~20:0.1~1. The ion-exchange resin is one or more of zinc acrylate and copper acrylate resins; The solvent is one or a combination of xylene, butyl acetate, ethyl acetate, MIBK, cyclohexanone, methyl ethyl ketone, and methyl isobutyl ketone. The thixotropic agent is one or a combination of two of fumed silica, hydrogenated castor oil, organobentonite, and polyamide wax; the plasticizer is any one or a combination of 42#, 52#, and 70# chlorinated paraffin. The biocidal agent is one or more of the following: cuprous oxide, zinc oxide, CuPT, ZnPT, zineb, brominated pyrrolidone, and DCOIT. The silane ester resin is silane acrylate and silane methacrylate based on side chain degradation or main chain-side chain double decomposition technology; The pigments and fillers are one or more of the following: titanium dioxide, iron oxide red, iron oxide yellow, iron oxide black, talc powder, mica powder, wollastonite powder, feldspar powder, barite powder, gypsum powder, and kaolin. When the auxiliary agent A is a combination of ethyl silicate and carbodiimide compounds, the weight ratio of ethyl silicate to carbodiimide compounds is (1~3):(0.5~1).

2. A method for preparing the hydrolytic linear self-polishing antifouling coating according to claim 1, characterized in that, Includes the following steps: Step A: Add ion exchange resin, solvent and plasticizer to the mixing tank under medium speed stirring, then add thixotropic agent, and disperse at medium speed until gelation is achieved. The stirring speed is 600~1000 r / min. Step B: Add biocides and pigments / fillers into the mixing tank under high-speed dispersion, and disperse at high speed until the fineness meets the requirements. The high-speed stirring speed is 1000~1500 r / min. Step C: Add silane ester resin and additive A under medium-speed stirring, and disperse at medium speed for 15 minutes, wherein the stirring speed is 600~1000 r / min; Step D: Package the obtained paint to obtain the finished antifouling paint.

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