Preparation method of main-chain degradable and side-chain complexing slow-release copper ion marine antifouling coating resin

Abstract

The invention discloses a preparation method of a marine antifouling coating resin with a degradable main chain and a side chain for complexing and slowly releasing copper ions. First, halogenated propylene glycol, dihydroxy polycaprolactone and diisocyanate are subjected to condensation to prepare a main chain degradable polyurethane prepolymer, and then poly(dimethylaminoethyl acrylate) with a brush shape is grafted by atom transfer radical polymerization (ATRP) to prepare a coating resin with a degradable main chain and a side group with copper ion complexing function. The polymer resin is used as a film-forming matrix for marine antifouling coatings. Its advantage lies in achieving the purpose of self-renewal by degrading the main chain of the coating resin and coupling antifouling by complexing and slowly releasing copper ions at the coating interface, and minimizing the marine environmental pollution caused by the excessive use of copper antifoulants.

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 will increase the weight of marine vessels, marine equipment, etc., increase the energy consumption of the transportation industry and the maintenance costs of equipment; secondly, the attached marine organisms will secrete acidic substances, which may penetrate the anti-corrosion primer of the equipment, accelerate corrosion, and cause a significant reduction in 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 cost-effective and effective marine antifouling method. However, the film-forming agent of current copper-containing antifouling coatings is a copolymer of an alkyl acrylate and an organosilicone acrylate. These coatings release the antifouling agent, cuprous oxide, through hydrolysis of the organosilicone acrylate, with its renewal rate dependent on the organosilicone acrylate content in the resin film-forming agent. 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. Consequently, it forms microplastics in the ocean, causing marine environmental pollution. Furthermore, the released copper ions, under the influence of seawater, are largely unable to remain at the coating interface for long and are rapidly lost to the seawater, losing their antifouling effect. Therefore, to achieve satisfactory antifouling results, antifouling coatings often incorporate cuprous oxide antifouling agents at levels far exceeding theoretical levels. The excessive use of copper antifouling agents has severely impacted the regeneration of offshore ecological environments. Therefore, given the irreplaceable nature of copper-based antifouling coatings, improving the efficiency of copper antifouling agents and reducing copper release are currently the most significant initiatives.

[0004] Organic tertiary amine compounds have been shown to effectively complex copper compounds in seawater (see Journal of Chemistry in Universities and Colleges 2018, 39, 1602-1610, Progress in Organic Coatings 2022, 170, 107003). To address the issues of short copper ion residence time at the coating interface and difficult degradation of the film-forming resin in traditional acrylic resin self-polishing copper-based antifouling coatings, the present invention designs a brush-like polymer that innovatively chemically bonds the complexing side chain to a degradable main chain, achieving molecular-level main chain degradation, interfacial copper ion complexation and coordination enrichment, and self-renewal synergistic antifouling performance. This effectively overcomes the problems of unstable copper release from antifouling agents and the formation of marine microplastics caused by traditional antifouling coatings. Summary of the Invention

[0005] A preparation method of a marine antifouling coating resin with a degradable main chain and a side chain for complexing and sustained release of copper ions realizes the preparation of a novel functional marine antifouling resin with a degradable main chain by controllably preparing a side chain polymer containing bifunctional end groups and having a copper ion complexing function. Compared with the existing widely used marine antifouling coating resins of the intractable degradation acrylic series, the advantages of the resin of the present invention for the film-forming substance of the marine antifouling coating are as follows: 1. The main chain is degradable and is not easily formed into marine microplastics; 2. The coating can achieve self-renewal at the molecular level, rather than the hydrolysis of the side groups of the existing marine antifouling coating acrylic resin, and the degree of polymerization of the main chain macromolecule remains unchanged; 3. The structural unit with a complexing function is chemically bonded to the main chain. Different from the physically blended complexing polymer, it will not be quickly lost at the coating interface due to seawater scouring, improving the mainstream time of copper ions, so that the regulation of copper ion release is more stable, which is beneficial to giving full play to the utilization efficiency of the copper antifouling agent, thereby reducing the amount of copper used and reducing its pollution to the marine environment.

[0006] To achieve the above, the present invention provides the following technical solutions:

[0007] A preparation method of a marine antifouling coating resin with a degradable main chain and a side chain for complexing and sustained release of copper ions. The preparation reaction of the coating resin is as follows in Formula 1:

[0008]

[0009] In the above formula, the structure of the halohydrin is as follows in Formula 2 or 3, where X is chlorine or bromine.

[0010]

[0011] The HO—PCL—OH described in the present invention is dihydroxy polycaprolactone;

[0012] The OCN—R—NCO described in the present invention is a diisocyanate, where the group *—R—* is one or a mixture of several of the following Formulas 4 to 13. Among them, in Formula 13, m3 is an integer between 0 and 20.

[0013]

[0014] In the catalyst CuX described in the present invention, X is chlorine or bromine;

[0015] The ligand described in the present invention is one or a mixture of 2,2'-bipyridine, pentamethyldiethylenetriamine or hexamethyltriethylenetetramine;

[0016] The number of repeating units n of the dihydroxy poly(dimethylaminoethyl methacrylate) a described in the present invention is 10 to 100. In the repeating units of the main chain of the polymer a, m1 is an integer between 10 and 100, and m2 = an integer between 10 and 200;

[0017] The molecular weight of the dihydroxy polycaprolactone HO-PCL-OH used in the present invention is between 1000 and 5000;

[0018] The solvent described in the present invention is one or a mixture of xylene, methyl ethyl ketone and cyclohexanone;

[0019] The specific preparation process of the marine antifouling coating resin described in the present invention is as follows: Add 10-100 mmol of halogenated propanediol, 500-5000 mL of solvent, 10-200 mmol of HO-PCL-OH and 20-300 mmol of OCN-R-NCO into a three-necked flask, and at a temperature of 25-80 °C, stir for a stepwise polymerization reaction for 2-10 h to obtain a main-chain degradable polymer a; Add 10-100 mmol of CuX as a catalyst, 10-200 mmol of ligand and 100-10000 mmol of dimethylaminoethyl methacrylate into the above system into a three-necked flask, and under nitrogen protection, stir at 50-100 °C for an ATRP polymerization reaction for 2-24 h to obtain a main-chain degradable and side-chain complexing slow-release copper ion marine antifouling coating resin b. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of copper ion release of three coatings A, B, and C. Specific Embodiments

[0021] Example 1:

[0022] Add 10 mmol of 3-chloro-1,2-propanediol, 500 mL of xylene, 10.2 mmol of dihydroxy polycaprolactone with a molecular weight of 5000 and 20 mmol of OCN-(CH2)6-NCO into a three-necked flask, and at a temperature of 80 °C, stir for a stepwise polymerization reaction for 2 h to generate polymer a1; Add 200 mmol of dimethylaminoethyl methacrylate monomer and 20 mmol of pentamethyldiethylenetriamine ligand to the above system, then add 10 mmol of CuBr catalyst, purify oxygen by passing nitrogen, raise the temperature to 100 °C, and stir for an ATRP polymerization reaction for 2 h under nitrogen protection to obtain a main-chain degradable and side-chain complexing copper ion marine antifouling coating resin b1.

[0023] Example 2:

[0024] Add 30 mmol of 2-chloro-1,3-propanediol, 2500 mL of xylene, 50 mmol of dihydroxy polycaprolactone with a molecular weight of 2000, and 79.2 mmol of diphenylmethane diisocyanate into a three-necked flask. At a temperature of 80 °C, stir for a stepwise polymerization reaction for 10 h to produce polymer a2; add 1000 mmol of dimethylaminoethyl methacrylate monomer and 30 mmol of hexamethyltriethylenetetramine ligand to the above system, then add 30 mmol of CuCl catalyst, purge with nitrogen to remove oxygen, raise the temperature to 80 °C, and carry out an ATRP polymerization reaction for 8 h under nitrogen protection to obtain a main-chain degradable and side-chain copper-ion complexing marine antifouling coating resin b2.

[0025] Example 3:

[0026] Add 20 mmol of 3-bromo-1,2-propanediol, 4000 mL of butanone, 100 mmol of dihydroxy polycaprolactone with a molecular weight of 5000, and 118.8 mmol of m-phenylene diisocyanate into a three-necked flask. At a temperature of 50 °C, carry out a stepwise polymerization reaction for 10 h to produce polymer a3; add 1600 mmol of dimethylaminoethyl methacrylate monomer and 40 mmol of 2,2'-bipyridine ligand to the above reaction system, then add 20 mmol of CuBr catalyst, purge with nitrogen to remove oxygen, raise the temperature to 70 °C, and stir for an ATRP polymerization reaction for 10 h under nitrogen protection to obtain a main-chain degradable and side-chain copper-ion complexing marine antifouling coating resin b3.

[0027] Example 4:

[0028] Add 30 mmol of initiator 2-bromo-1,3-propanediol, 5000 mL of cyclohexanone, 80 mmol of dihydroxy polycaprolactone with a molecular weight of 5000, and 109 mmol of isophorone diisocyanate into a three-necked flask. At a temperature of 60 °C, stir for a stepwise polymerization reaction for 8 h to produce polymer a4; add 2400 mmol of dimethylaminoethyl methacrylate monomer and 60 mmol of 2,2'-bipyridine ligand to the above reaction system, then add 30 mmol of CuBr catalyst, purge with nitrogen to remove oxygen, raise the temperature to 60 °C, and stir for an ATRP polymerization reaction for 10 h to obtain a main-chain degradable and side-chain copper-ion complexing marine antifouling coating resin b4.

[0029] Example 5:

[0030] Add 10 mmol of methyl 2-bromoisobutyrate, 10 mmol of copper(I) chloride, 20 mmol of pentamethyldiethylenetriamine, and 800 mmol of dodecyl methacrylate to a three-necked reaction flask. Purge with nitrogen to remove oxygen. Stir the reaction mixture at 50 °C for 2 hours. Then, add 800 mmol of deoxygenated 2-(dimethylamino)ethyl methacrylate to the reaction flask and continue stirring at 80 °C for 12 hours. The resulting poly(dodecyl methacrylate) 80 -b-poly(2-(dimethylamino)ethyl methacrylate) 80 is polymer a 80 ; Example 6:

[0031] Take 2 parts (20 g each) of self-made polycaprolactone resin (molecular weight 80,000), dissolve each part in 50 ml of cyclohexanone, and label them as resin A and resin B. Then, add 5 g of copper(I) oxide powder to resin A and stir at a speed of 1500 revolutions per minute for 20 minutes to obtain coating A; add 3.3 g of the poly(dodecyl methacrylate)80-b-poly(2-(dimethylamino)ethyl methacrylate)80 prepared in Example 5 (polymer a80) and 5 g of copper(I) oxide powder to resin B and stir at a speed of 1500 revolutions per minute for 20 minutes to obtain coating B; take 20 g of resin b4 from Example 4, add 5 g of copper(I) oxide, and stir at a speed of 1500 revolutions per minute for 20 minutes to obtain coating C. Take 3 epoxy resin plates of 20 cm × 20 cm, apply coatings A, B, and C respectively, and after natural drying for 5 days, obtain coatings A, B, and C. Test the copper ion release rate according to Method A of GB / T 6822-2014 for a total of 17 weeks. The obtained test curves are shown in the attached Figure 1 :

[0032] The results in the above figure show that compared with coating A without complexing function and coating B with a physically blended complexing antifouling agent, the antifouling coating C with complexing function obtained in the present invention has a more stable slow-release effect on the copper antifouling agent.

[0033] The preparation method of a main-chain degradable and side-chain complexing slow-release copper ion marine antifouling coating resin provided by the present invention is introduced in detail above. Specific examples are used in this article to elaborate on the principle and implementation mode of the present invention. The description of the above examples is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also belong to the scope of the protection of the present invention's rights.

Claims

1. A preparation method of a marine antifouling coating resin with a degradable main chain and a complexing and sustained-release copper ion side chain, characterized in that, The preparation reaction of the coating resin is as shown in Formula 1 below: In the above formula, the structure of the halopropanediol is shown in Formula 2 or 3 below, where X is chlorine or bromine. HO—PCL—OH is dihydroxy polycaprolactone; OCN—R—NCO is a diisocyanate, where the group *—R—* is one or a mixture of several of the following Formulas 4 to 13. Among them, in Formula 13, m3 is an integer between 0 and 20; In the catalyst CuX, X is chlorine or bromine; The ligand is one or a mixture of 2,2'-bipyridine, pentamethyldiethylenetriamine or hexamethyltriethylenetetramine; In the polymer a main chain, the repeating unit m1 is an integer of 10 to 100, and m2 = an integer of 10 to 200; The number of repeating units n in the resin b is an integer of 10 to 100; The specific preparation process of the marine antifouling coating resin is as follows: Add 10 to 100 mmol of halopropanediol, 500 to 5000 mL of solvent, 10 to 200 mmol of HO—PCL—OH and 20 to 300 mmol of OCN—R—NCO into a three-necked flask, and carry out a stepwise polymerization reaction at a temperature of 25 - 80 °C for 2 - 10 h to obtain the main chain degradable polymer a; Add 10 - 100 mmol of CuX as a catalyst, 10 - 200 mmol of ligand and 100 - 10000 mmol of dimethylaminoethyl methacrylate to the above system in the three-necked flask, and carry out an ATRP polymerization reaction at 50 - 100 °C under nitrogen protection for 2 - 24 h to obtain the marine antifouling coating resin b with a main chain degradable and side chain complexing and slow-releasing copper ions.

2. The preparation method of a marine antifouling coating resin with a degradable main chain and a complexing and sustained-release copper ion side chain according to claim 1, characterized in that, The molecular weight of the used dihydroxy polycaprolactone HO—PCL—OH is between 1000 and 5000.

3. The preparation method of a marine antifouling coating resin with a biodegradable main chain and a complexing and sustained-release copper ion side chain according to claim 1, characterized in that, The said solvent is one or a mixture of xylene, methyl ethyl ketone and cyclohexanone.

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