Preparation method of marine antifouling coating resin with copper ion slow-release function

Abstract

The present invention discloses a method for preparing a marine antifouling coating resin with a copper ion slow-release function. First, a carboxyl-terminated polydimethylaminoethyl acrylate prepolymer is synthesized by free radical polymerization, and then the prepolymer is condensed with a diepoxy oxygen molecule to prepare a dihydroxy prepolymer. The resulting dihydroxy prepolymer, dihydroxy polycaprolactone, and diisocyanate are condensed to prepare a coating resin with a degradable main chain and copper ion complexing side groups. This polymer is used as a film-forming matrix for marine antifouling coatings. Its advantage is that the coating resin can effectively regulate the release of the copper antifouling agent and self-renew with main chain degradation to achieve a coupled antifouling effect.

Description

Technical Field

[0001] The invention belongs to the field of polymer material synthesis, and in particular relates to a method for preparing a self-renewing marine antifouling material. Background Art

[0002] The attachment of marine fouling organisms increases the weight of marine vessels and equipment, increasing energy consumption in the transportation industry and equipment maintenance costs; the acidic substances they produce accelerate the corrosion of marine engineering metals, causing a significant reduction in their lifespan; according to statistics, the global economic losses caused by the attachment of fouling organisms exceed US$450 billion each year.

[0003] Antifouling coatings are considered a low-cost and effective protective measure. The film-forming agent of mainstream copper-containing antifouling coatings is a copolymer of alkyl acrylates and organosilicone acrylates. These coatings renew the coating through hydrolysis of the silicone acrylates, releasing the antifouling agent cuprous oxide. However, the backbone of the polyacrylic resin film-forming agent in traditional antifouling coatings is composed of a polyolefin structure, which is extremely difficult to degrade under natural conditions. This leads to the formation of microplastics in the ocean, causing marine environmental pollution. Furthermore, because the film-forming resin is exfoliated from the coating as a whole during the renewal process, the copper antifouling agent is not only released into the seawater as ions, but also washed away as oxide particles without antifouling effects. Therefore, its utilization efficiency needs to be improved. To achieve satisfactory antifouling effects, antifouling coatings often incorporate cuprous oxide antifouling agents at levels far exceeding theoretical levels. The excessive use of copper antifouling agents has seriously impacted the regeneration of coastal ecosystems. Therefore, given the irreplaceable nature of copper-based antifouling coatings, improving their utilization efficiency and reducing copper release are crucial measures.

[0004] Organic tertiary amine compounds have been shown to effectively complex copper compounds in seawater (see, Journal of Chemistry of Universities 2018, 39, 1602-1610, Progress in Organic Coatings, 2022, 170, 107003).

[0005] To address the short residence time of copper ions at the coating interface and the difficulty in degrading the film-forming resin in traditional acrylic resin self-polishing copper-based antifouling coatings, and to improve copper ion utilization efficiency, the present invention devised a method for preparing a coating film-forming agent with a degradable backbone and complexing side groups. This resin achieves antifouling properties through molecular-level backbone degradation, interfacial copper ion complexation and enrichment, and self-renewal, effectively overcoming the challenges of unstable copper release and the formation of marine microplastics associated with traditional antifouling coatings. Summary of the Invention

[0006] A method for preparing a copper ion slow-release functional marine antifouling coating resin comprises preparing a carboxyl-terminated polymer with a copper ion complexing function by a classical free radical polymerization method, then utilizing the carboxyl-terminated polymer to undergo a ring-opening reaction with a diepoxide to obtain a dihydroxy complexing functional polymer intermediate, and further, subjecting the polymer intermediate to a condensation polymerization with a dihydroxy polyester and a diisocyanate to obtain a novel functional marine antifouling resin. Compared with the widely used difficult-to-degrade acrylic series marine antifouling coating resins, the advantages of the resin of the present invention for use in marine antifouling coating film-forming materials are: 1. The main chain is degradable and is not prone to forming marine microplastics; 2. The coating can achieve self-renewal at the molecular level, rather than the side group hydrolysis of the existing marine antifouling coating acrylic resin, while the polymerization degree of the main chain macromolecules remains unchanged; 3. The structural unit with a complexing function is chemically bonded to the main chain, and the coating will not be lost alone due to seawater scouring at the coating interface, so the complexing function is more stable, and the regulation of copper ion release is therefore more stable, which is conducive to the effective utilization of copper antifouling agents; 4. The film-forming resin is obtained by a one-pot continuous polymerization method, the preparation process is reasonably designed, and the obtained resin solution can be used directly without purification treatment, which is conducive to industrial production.

[0007] To achieve the above content, the present invention provides the following technical solutions:

[0008] A method for preparing a marine antifouling coating resin with a copper ion slow-release function. The preparation reaction of the coating resin is as follows:

[0009]

[0010] The number of repeating units n of polymer a in the above formula 1 of the present invention is 10 to 100;

[0011] In the structural formula of the diepoxide compound of the present invention, m is an integer from 4 to 12;

[0012] The solvent of the present invention is one of xylene, butanone and cyclohexanone or a mixture of the three;

[0013] The HO-PCL-OH described in the present invention is dihydroxy polycaprolactone;

[0014] The OCN—R'—NCO of the present invention is a diisocyanate, wherein the group *—R'—* is one or a mixture of several of the following formulas 2 to 10, wherein m1 in formula 11 is an integer between 0 and 20,

[0015]

[0016] The repeating units m2 and m3 in the main chain of the polymer b of the present invention are integers of 10 to 100 respectively;

[0017] The specific preparation process of the marine antifouling coating resin of the present invention is as follows: 10-100 mmol of azobiscyanovaleric acid initiator, 10-100 mmol of a diepoxide and 200-20000 mmol of dimethylaminoethyl methacrylate are added to a three-necked flask, and polymerization and ring-opening reaction are carried out at 60-80° C. under nitrogen protection for 2-10 hours to produce bishydroxy polydimethylaminoethyl methacrylate a; 500-5000 mL of solvent is added to the reaction system, and then 10-100 mmol of HO-PCL-OH and 20-200 mmol of OCN-R-NCO are added, and stepwise polymerization reaction is carried out at 25-80° C. for 2-10 hours to produce marine antifouling coating resin b with a degradable main chain and a side chain complexed slow-release copper ion.

[0018] The molecular weight of the dihydroxy polycaprolactone HO-PCL-OH used in the present invention is between 1000 and 5000. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is a schematic diagram showing the sustained-release effect of the antifouling coating resin of the present invention. DETAILED DESCRIPTION

[0020] Example 1:

[0021] 10 mmol of azobiscyanovaleric acid (initiator), 10 mmol of 1,4-butanediol glycidyl ether, and 200 mmol of dimethylaminoethyl methacrylate (DMMA) were placed in a three-necked flask, deoxygenated with nitrogen, and heated to 80°C. The mixture was reacted under nitrogen for 2 hours to produce 10 mmol of bishydroxy poly(DMMA) a1. 500 mL of xylene was added to the reaction system, followed by 10 mmol of 5000 molecular weight HO—PCL—OH and 20.2 mmol of OCN—(CH2)6—NCO. A stepwise polymerization reaction was carried out at 50°C for 2 hours to produce a marine antifouling coating resin b1 with a biodegradable backbone and side chain complexed, slow-release copper ions.

[0022] Example 2:

[0023] 10 mmol of azobiscyanovaleric acid (initiator), 10 mmol of 1,6-hexanediol glycidyl ether, and 1000 mmol of dimethylaminoethyl methacrylate (DMMA) were placed in a three-necked flask, deoxygenated with nitrogen, and heated to 60°C. The mixture was reacted under nitrogen for 5 hours to produce 10 mmol of bishydroxypoly(DMMA) a2. To this reaction system, 1000 mL of butanone, 50 mmol of 3000 molecular weight HO—PCL—OH, and 59.4 mmol of diphenylmethane diisocyanate were added. A stepwise polymerization reaction was carried out at 60°C for 2 hours to produce marine antifouling coating resin b2 with a biodegradable backbone and side chain complexed slow-release copper ions.

[0024] Example 3:

[0025] 10 mmol of azobiscyanovaleric acid initiator, 10 mmol of 1,6-hexanediol glycidyl ether, and 2000 mmol of dimethylaminoethyl methacrylate were added to a three-necked flask, and the mixture was stirred and polymerized at 80°C for 10 hours under nitrogen protection to produce 10 mmol of bishydroxypolydimethylaminoethyl methacrylate a3. 2000 mL of cyclohexanone was added to the above reaction system, followed by 100 mmol of HO-PCL-OH with a molecular weight of 2000 and 109 mmol of isophorone diisocyanate. The mixture was gradually polymerized at 80°C for 10 hours to obtain a marine antifouling coating resin b3 with a degradable main chain and a side chain complexed slow-release copper ion.

[0026] Example 4:

[0027] Take 20 grams of one homemade polycaprolactone resin (molecular weight 80,000), dissolve it in 50 ml of cyclohexanone, and mark it as resin A. Then, add 5 grams of cuprous oxide powder to resin A and stir at 1500 rpm for 20 minutes to obtain coating A; take about 57 grams of the resin solution b1 prepared in Example 1, add 5 grams of cuprous oxide powder, and stir at 1500 rpm for 20 minutes to obtain coating B; take two 20 cm × 20 cm epoxy resin boards, apply coatings A and B respectively, and after natural drying for 5 days, obtain coatings A and coating B. The copper ion release rate is tested according to GB / T6822-2014 method A for a total of 17 weeks. The obtained test curve is shown in Figure 1.

[0028] The results in FIG1 show that the antifouling coating resin with a complexing function obtained by the present invention has a significant sustained-release effect on the copper antifouling agent (coating B curve), and the release of copper ions is very stable; while the comparison curve (coating A curve) shows excessive release in the early stage and insufficient release in the later stage, affecting the antifouling effect.

[0029] The above is a detailed introduction to the preparation method of a copper ion sustained-release marine antifouling coating resin provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A method for preparing a copper ion slow-release marine antifouling coating resin, characterized in that: The preparation reaction of the coating resin is as follows: In the above formula 1: The number n of repeating units of polymer a is 10 to 100; m in the diepoxide structural formula is an integer from 4 to 12; The solvent is one of xylene, butanone and cyclohexanone or a mixture of the three; HO—PCL—OH is dihydroxy polycaprolactone; OCN—R'—NCO is a diisocyanate, in which the group *—R'— * is one or more of the following formulas 2 to 11, wherein m1 in formula 11 is an integer between 0 and 20, The repeating units m2 and m3 in the main chain of polymer b are integers of 10 to 100; The specific preparation process of the marine antifouling coating resin is as follows: 10-100 mmol of azobiscyanovaleric acid initiator, 10-100 mmol of diepoxide and 200-20000 mmol of dimethylaminoethyl methacrylate are added to a three-necked flask, and polymerization and ring-opening reaction are carried out at 60-80°C under nitrogen protection for 2-10 hours to produce bishydroxy polydimethylaminoethyl methacrylate a; then 500-5000 mL of solvent is added to the polymer a system, and then 10-100 mmol of HO-PCL-OH and 20-200 mmol of OCN-R-NCO are added, and stepwise polymerization reaction is carried out at 25-80°C for 2-10 hours to obtain a marine antifouling coating resin b with a degradable main chain and a side chain complexed slow-release copper ion.

2. The method for preparing a copper ion slow-release marine antifouling coating resin according to claim 1, characterized in that: The molecular weight of the used dihydroxy polycaprolactone HO-PCL-OH is between 1000 and 5000.

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