Modified silicone marine antifouling coatings based on energy dissipation

Abstract

The present invention discloses a modified organosilicon marine antifouling coating based on energy dissipation, by introducing hydroxyl groups into modified polysiloxane resin, thereby utilizing the chemical crosslinking and hydrogen bonding effect of polar hydroxyl groups to enhance the bonding force between the cured coating and various substrates. More prominently, positively charged groups are introduced into the modified polysiloxane resin to ensure effective energy dissipation of the polymer, and its loss factor tanδ is relatively stable and close to 1 within a suitable temperature range, thereby ensuring that the cured coating fully utilizes the hydrogen bonding effect to achieve a firm bond with various substrates. On this basis, the hydrophobic siloxane main chain structure still ensures the hydrophobicity and low surface energy characteristics of the cured coating, achieving excellent antifouling effects. The coating can be widely used in various aspects of the marine antifouling field, and is particularly suitable for various marine industrial facilities that are immersed in seawater environments for a long time.

Description

Technical Field

[0001] The invention belongs to the field of marine antifouling technology and underwater coating protection technology, and particularly relates to a modified organic silicon marine antifouling coating based on energy dissipation. Background Art

[0002] Since the Industrial Revolution, with the application of toxic marine antifouling coatings such as cuprous oxide and organotin, the adhesion of fouling organisms is prevented by indiscriminate killing of marine organisms, which is effective and cost-effective, making great contributions to the ocean and maritime industry. However, with the improvement of human environmental awareness and the development of science and technology, traditional toxic marine antifouling coatings, while inhibiting the adhesion of fouling, have also caused immeasurable harm to the marine environment, causing the death of marine microorganisms and the mutation of large marine organisms, and ultimately endangering human safety through enrichment in the food chain. Therefore, the International Maritime Organization passed the "Convention on the International Control of Harmful Anti-fouling Systems on Ships" (AFS Convention), prohibiting the use of organotin and cyclobutanenitrile-based toxic marine antifouling coatings, and strictly restricting the application of cuprous oxide antifouling coatings. And my country's environmental protection department has also included cuprous oxide antifouling coatings in the production blacklist.

[0003] The ban trend of traditional marine antifouling coatings Humans have started to apply environmentally friendly marine antifouling coatings, and fouling-releasing, fouling-inhibiting, and fouling-degrading marine antifouling coatings have emerged. Among them, fouling-releasing marine antifouling coatings use physical methods to prevent fouling. While minimizing the amount of marine fouling organisms adhering, they also maximize the weakening of the adhesion strength of fouling organisms, thereby achieving a physical antifouling mechanism of re-releasing the adhering fouling organisms into the ocean through high-speed scouring during the operation of the ship. It is environmentally friendly and reliable, so it has been commercially applied. The two major areas of fouling-releasing marine antifouling coatings are organosilicon and organofluorine marine antifouling coatings.

[0004] However, the main molecular chain structure of organosilicon marine antifouling coatings is a non-polar structure, so the bonding force on the polar ship surface and even the intermediate paint surface is poor, and it is easy to fall off during use, thus losing the antifouling effect. This has also become a major defect restricting the application of organosilicon marine antifouling coatings. At present, the common measure is to introduce polar functional groups through chemical modification, especially to graft hydroxyl groups on the polymer molecular chain, and achieve a firm bond to the substrate through chemical crosslinking and hydrogen bonding of hydroxyl groups. However, in actual use, the introduction of hydroxyl groups leads to reduced polymer flexibility and poor energy dissipation, which results in the actual adhesion and bonding failing to reach the ideal state of the design. Therefore, the application effect is not good and needs further improvement. Summary of the invention

[0005] In order to solve the problems that the traditional organic silicon marine antifouling coating has poor bonding effect with the substrate, and the conventional hydroxylated modified organic silicon marine antifouling coating has high strength, is easy to break, and affects the antifouling performance, the purpose of the present invention is to provide a modified organic silicon marine antifouling coating based on energy dissipation. The chemical crosslinking and hydrogen bonding generated by the hydroxyl group on the surface of various substrates promote the diffusion of the coating polymer chain, so that the coating is firmly bonded. At the same time, positive charge groups are introduced into the modified organic silicon polymer to promote the effective energy dissipation of the polymer. While ensuring the long-lasting and firm bonding of the cured coating, the loss factor tanδ of the polymer in a wide temperature range (0-40°C) is close to 1, thereby balancing the chain diffusion and energy dissipation, ensuring long-term stable bonding strength, and solving the problems that the hydroxylated modified organic silicon coating is easy to break during use and difficult to firmly and stably bond. At the same time, the main chain molecular structure is still a flexible polysiloxane structure, so the cured coating can maintain excellent hydrophobicity and low surface energy properties, thereby ensuring excellent antifouling effect during the use of the coating.

[0006] The present invention is implemented through the following technical solutions.

[0007] The modified organosilicon marine antifouling coating based on energy dissipation of the present invention comprises the following components in parts by weight:

[0008]

[0009] Wherein, the modified silicone resin / ethanol mixture is prepared by the following steps:

[0010] (1) In a reaction kettle protected by nitrogen, methyl vinyl MQ type silicone resin, ethanol, monomers having hydroxyl groups and unsaturated groups, cationic monomers, and acrylamide monomers are added in sequence, and stirred at 50 to 150 rpm for 5 to 15 minutes;

[0011] (2) then adding azobisisobutyronitrile initiator, maintaining nitrogen protection, heating to 50-80°C, and reacting for 6-12 hours;

[0012] (3) The product after the reaction is washed with acetone in a Soxhlet extractor for 2 to 6 hours, and the washed product modified silicone resin is dissolved in an equal weight portion of ethanol to obtain a modified silicone resin / ethanol mixture, which is then sealed and stored in the dark.

[0013] Furthermore, the weight ratio of the methyl vinyl MQ type silicone resin, ethanol, the monomer having a hydroxyl group and an unsaturated group, the cationic monomer, and the acrylamide monomer is (50-80): (100-150): (20-30): (5-15): (2-8).

[0014] Furthermore, the methyl vinyl MQ type silicone resin is selected from a M:Q value of ≥1.3:1, or is liquid at 25°C.

[0015] Furthermore, the monomer having a hydroxyl group and an unsaturated group is selected from one of 3-(acryloyloxy)-2-hydroxypropyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, 2-(hydroxymethyl)methyl acrylate, and N-hydroxymethyl methacrylamide.

[0016] Furthermore, the cationic monomer is selected from one of N-(2-acryloyloxyethyl)-N-benzyl-N,N-dimethylammonium chloride, [2-(methacryloyloxy)ethyl]trimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, and trimethylallylammonium chloride.

[0017] Furthermore, the acrylamide monomer is selected from acrylamide, methacrylamide, dimethylaminopropyl acrylamide, N-phenylmethacrylamide, and N-tert-butylacrylamide.

[0018] Furthermore, the azobisisobutyronitrile initiator is 1% of the total weight of the reactant monomers (including methyl vinyl MQ type silicone resin, monomers with hydroxyl groups and unsaturated groups, cationic monomers, and acrylamide monomers).

[0019] Furthermore, the pigments and fillers are commonly used pigments and fillers for marine antifouling coatings.

[0020] Specifically, the pigment filler is selected from but not limited to talc, heavy calcium powder, zinc oxide, titanium dioxide, nano silicon dioxide, nano ferrosoferric oxide, barium sulfate, and tourmaline.

[0021] Furthermore, the auxiliary agent is at least one of a dispersant, a defoamer and a leveling agent.

[0022] Specifically, the dispersant is one of German BYK-161, BYK-163 and BYK-167.

[0023] Specifically, the defoaming agent is one of BYK066N, BYK-141, BYK-071 and BYK-060N produced by German BYK.

[0024] Specifically, the leveling agent is one of BYK-306, BYK-307 and BYK-330 produced by German BYK.

[0025] Furthermore, the solvent is one of ethanol, methanol, butanone, ethyl acetate, and ethylene glycol.

[0026] The preparation method of the modified organosilicon marine antifouling coating based on energy dissipation can be prepared by a conventional marine antifouling coating preparation method without any special requirements.

[0027] As a preferred embodiment, a method for preparing a modified organosilicon marine antifouling coating based on energy dissipation is provided, comprising the following steps:

[0028] (1) Add the modified silicone resin / ethanol mixture, the additive, and the solvent into a stirring and dispersing device in sequence, and stir at 50 to 200 rpm for 5 to 10 minutes;

[0029] (2) Add pigments and fillers into a stirring and dispersing device, increase the speed to 150-300 rpm, and stir for 30-60 minutes to obtain the marine antifouling coating, which is then sealed and stored away from light.

[0030] The antifouling coating is applied by brushing, spraying or rolling to prepare an antifouling coating with a film thickness of 150 to 250 μm on the surface of the substrate after drying and curing.

[0031] Compared with the prior art, the present invention has the following excellent effects:

[0032] 1. The present invention introduces hydroxyl groups into the molecular chain structure of non-polar polysiloxane polymers and utilizes chemical crosslinking and hydrogen bonding between the hydroxyl groups and various substrates to achieve bonding with various substrates.

[0033] 2. While achieving bonding, quaternary ammonium salt groups are introduced into the molecular chain structure of the polysiloxane polymer to achieve the introduction of positively charged groups, and the positively charged groups are used to achieve excellent energy dissipation of the modified polymer. In the wide range of marine antifouling coating applications (0-40°C), excellent energy dissipation ensures that the coating's dissipation factor tanδ is close to 1, thereby balancing chain diffusion and energy dissipation, thereby achieving a firm bond between the cured coating and the surface of various substrates, avoiding the introduction of hydroxyl groups that leads to reduced polymer flexibility and poor energy dissipation, which leads to the occurrence of loose bonding.

[0034] 3. The hydroxyl group and the positively charged group as functional groups are both present in the side chains of the polymer molecular structure, while the main chain structure is still a flexible polysiloxane structure. Therefore, the cured coating still maintains excellent low surface energy characteristics during actual use, thereby ensuring excellent anti-fouling effect. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, without departing from the concept of the present invention, several variations and improvements can also be made, which belong to the protection scope of the present invention.

[0036] The modified organosilicon marine antifouling coating based on energy dissipation of the present invention introduces hydroxyl groups into the flexible polysiloxane polymer molecular structure, based on the chemical crosslinking and hydrogen bonding of the hydroxyl groups, realizes the firm bonding of the cured coating and various substrates, and simultaneously introduces the quaternary ammonium salt group by modification to introduce the positive charge group into the polysiloxane polymer molecular structure, realizes the excellent energy dissipation of the polymer based on the presence of the positive charge group, in the wide range (0-40° C.) of the application of the marine antifouling coating, the excellent energy dissipation ensures that the dissipation factor tanδ of the coating is close to 1, thereby balancing the chain diffusion and the energy dissipation, thereby realizing the firm bonding of the cured coating on the surface of various substrates, avoiding the introduction of the hydroxyl groups to cause the polymer flexibility to decrease, the energy dissipation to deteriorate, thereby causing the occurrence of the phenomenon of weak bonding. At the same time, the main chain structure of the final cured coating molecule is still the polysiloxane structure, so the lower surface free energy of the coating can be maintained, and the excellent antifouling effect is guaranteed.

[0037] The raw materials used in the examples are shown in Table 1. The specific implementation is not limited to the raw materials in Table 1, and corresponding products can be selected according to the above. Other raw materials used in the examples are all commercially available chemical reagents.

[0038] Table 1

[0039]

[0040]

[0041] Preparation of modified silicone resin / ethanol mixture 1

[0042] Methyl vinyl MQ type silicone resin, ethanol, monomers having hydroxyl groups and unsaturated groups, cationic monomers, and acrylamide monomers are prepared in a weight ratio of 50:120:30:12:8. The specific preparation process is as follows:

[0043] (1) In a reaction kettle protected by nitrogen, methyl vinyl MQ type silicone resin 1-1, ethanol, monomer 2-1 having a hydroxyl group and an unsaturated group, cationic monomer 3-2, and acrylamide monomer 4-1 are added and stirred at 100 rpm for 15 minutes;

[0044] (2) Then, add azobisisobutyronitrile initiator, keep nitrogen protection, raise the temperature to 65°C, and react for 10 hours;

[0045] (3) The product after the reaction was washed with acetone in a Soxhlet extractor for 3 hours, and the washed polymer was dissolved in an equal weight portion of ethanol to obtain a modified silicone resin / ethanol mixture, which was then sealed and stored away from light.

[0046] Preparation of modified silicone resin / ethanol mixture 2

[0047] Methyl vinyl MQ type silicone resin, ethanol, monomers having hydroxyl groups and unsaturated groups, cationic monomers, and acrylamide monomers are prepared in a weight ratio of 70:100:24:5:2. The specific preparation process is as follows:

[0048] (1) In a reaction kettle protected by nitrogen, methyl vinyl MQ type silicone resin 1-2, ethanol, monomer 2-2 having a hydroxyl group and an unsaturated group, cationic monomer 3-1, and acrylamide monomer 4-1 are added and stirred at 150 rpm for 5 minutes;

[0049] (2) Then, add azobisisobutyronitrile initiator, keep nitrogen protection, raise the temperature to 50°C, and react for 12 hours;

[0050] (3) The product after the reaction was washed with acetone in a Soxhlet extractor for 6 hours, and the washed polymer was dissolved in an equal weight portion of ethanol to obtain a modified silicone resin / ethanol mixture, which was then sealed and stored away from light.

[0051] Preparation of modified silicone resin / ethanol mixture 3

[0052] Methyl vinyl MQ type silicone resin, ethanol, monomers having hydroxyl groups and unsaturated groups, cationic monomers, and acrylamide monomers are prepared in a weight ratio of 80:150:20:15:6. The specific preparation process is as follows:

[0053] (1) In a reaction kettle protected by nitrogen, methyl vinyl MQ type silicone resin 1-2, ethanol, monomer 2-3 having a hydroxyl group and an unsaturated group, cationic monomer 3-3, and acrylamide monomer 4-2 are added and stirred at 50 rpm for 12 minutes;

[0054] (2) then adding azobisisobutyronitrile initiator, maintaining nitrogen protection, heating to 80°C, and reacting for 6 hours;

[0055] (3) The product after the reaction was washed with acetone in a Soxhlet extractor for 2 hours, and the washed polymer was dissolved in an equal weight portion of ethanol to obtain a modified silicone resin / ethanol mixture, which was then sealed and stored away from light.

[0056] Examples 1-5

[0057] The distribution ratios of each group in Examples 1-5 are shown in Table 2.

[0058] Table 2

[0059]

[0060] Example 1

[0061] The ingredients are prepared according to Table 2, and the specific preparation steps are as follows:

[0062] (1) Add the modified silicone resin / ethanol mixture, additives, and solvent into a stirring and dispersing device in sequence, and stir at 80 rpm for 7 minutes;

[0063] (2) Add pigments and fillers into the stirring and dispersing equipment, increase the speed to 150 rpm and stir for 60 minutes;

[0064] (3) The stirred mixture is sealed and stored away from light to obtain the prepared marine antifouling coating.

[0065] The antifouling coating is applied by brushing to prepare on the surface of the substrate a film thickness of 150 to 250 μm after drying and curing.

[0066] Example 2

[0067] The ingredients are prepared according to Table 2, and the specific preparation steps are as follows:

[0068] (1) Add the modified silicone resin / ethanol mixture, additives, and solvent into a stirring and dispersing device in sequence, and stir at 200 rpm for 5 minutes;

[0069] (2) Add pigments and fillers into the stirring and dispersing equipment, increase the speed to 300 rpm and stir for 30 minutes;

[0070] (3) The stirred mixture is sealed and stored away from light to obtain the prepared marine antifouling coating.

[0071] The antifouling coating is applied by brushing to prepare on the surface of the substrate a film thickness of 150 to 250 μm after drying and curing.

[0072] Embodiment 3-5

[0073] The ingredients are prepared according to Table 2, and the specific preparation steps are as follows:

[0074] (1) Add the modified silicone resin / ethanol mixture, additives, and solvent into a stirring and dispersing device in sequence, and stir at 50 rpm for 10 min;

[0075] (2) Add pigments and fillers into the stirring and dispersing equipment, increase the speed to 200 rpm and stir for 40 minutes;

[0076] (3) The stirred mixture is sealed and stored away from light to obtain the prepared marine antifouling coating.

[0077] The antifouling coating is applied by brushing to prepare on the surface of the substrate a film thickness of 150 to 250 μm after drying and curing.

[0078] Comparative Example 1

[0079] Compared with Example 1, the synthesis of the modified silicone resin does not include a cationic monomer, and the remaining components and weight parts are the same, and the preparation steps are the same as those of Example 1.

[0080] By using conventional coating methods such as brush coating, spray coating, and roller coating, an antifouling coating having a film thickness of 150 to 250 μm after drying and curing is prepared on the surface of the substrate.

[0081] Comparative Example 2

[0082] The common organosilicon low surface energy marine antifouling paint comprises the following raw materials in parts by weight: 90.0 parts of polysiloxane resin, 30.0 parts of pigments and fillers, 4.0 parts of cross-linking curing agent, 1.5 parts of catalyst, 0.5 parts of auxiliary agent and 0.0 parts of third solvent.

[0083] The polysiloxane resin is α, ω-dihydroxy polydimethylsiloxane with a viscosity of 10000 mPa·s; the pigment is zinc oxide; the cross-linking curing agent is tetraethyl orthosilicate; the catalyst is dibutyltin disilicate; the auxiliary agent is 0.5 parts of BYK161 dispersant from BYK; and the solvent is xylene.

[0084] (1) 90.0 parts of α,ω-dihydroxy polydimethylsiloxane with a viscosity of 10000 mPa·s and 30.0 parts of micron-sized zinc oxide were added to a disperser and dispersed at 300 rpm for 30 min. Subsequently, 0.5 parts of BYK161 dispersant from BYK was added to the disperser at 200 rpm and dispersed for 30 min. The mixture was then ground with a sand mill to a fineness of less than 40 μm to prepare a pre-dispersed slurry and canned for standby use.

[0085] (2) 4.0 parts of tetraethyl orthosilicate and 10.0 parts of xylene were mixed evenly to prepare a crosslinking curing agent component, which was then canned for standby use; 1.5 parts of dibutyltin dioxysilicate and 20.0 parts of xylene were mixed evenly to prepare a catalyst component, which was then canned for standby use;

[0086] (3) Before use, the pre-dispersed slurry, the cross-linking curing agent component, and the catalyst component are stirred uniformly according to the ratio. After the obtained coating is applied and cured, a common organic silicon low surface energy marine antifouling coating with a thickness of 150 to 200 μm is obtained.

[0087] Test 1: Surface Free Energy

[0088] The contact angles of deionized water and diiodomethane on the coating surface were measured using an XG-CAMC3 fully automatic contact angle meter produced by Shanghai Xuanzhun Instrument Co., Ltd. The surface energy of the coating was then calculated using the Owens two-liquid method.

[0089] Test 2: Pull-off method to measure adhesion (steel plate, aluminum plate, epoxy intermediate paint)

[0090] The BGD500 digital semi-automatic adhesion tester produced by Guangzhou Biaogeda Precision Instrument Co., Ltd. was used to measure the adhesion of the coating applied on the corresponding substrate or epoxy intermediate paint. The steel plate and aluminum plate needed to be polished with 800-grit sandpaper before use. The epoxy intermediate paint used was the epoxy micaceous iron intermediate paint produced by Shanghai Jinsi Di. The adhesion of the coating was tested after standing in sterilized aged seawater for 100 days.

[0091] Test 3: Antifouling performance test

[0092] A suspension containing at least 108 units of Streptococcus salivarius was dispersed in 20 ml of tryptic soy broth and incubated at 38°C, 5% CO2 for 2 hours. The suspension was then further diluted and inoculated in agar supplemented with 5% sheep blood and incubated at 38°C, 5% CO2 for 48 hours, and then the units containing six colonies were dispersed in 10 ml of tryptic soy broth. Subsequently, 20 ml of the above bacterial suspension was covered on the coating of 10×5 cm area and incubated at 38°C, 5% CO2 for 24 hours. After the incubation, each sample needed to be rotated and rinsed in 45 ml of distilled water for 30 seconds, and then rinsed with 50 ml of distilled water to remove non-sticky materials. The surface-adherent bacteria were observed using a Simga300 scanning electron microscope produced by Carl Zeiss, Germany.

[0093] Test 4: Dissipation factor tanδ test (0~40℃)

[0094] The rheological properties of the prepared coating were tested using Anton Parker's MCR-302 rheometer, with a frequency scan of 0 to 40°C in the range of 0.1 to 100 Hz from 0.001% to 0.5% strain at 1 Hz. The dissipation factor tanδ of the coating was obtained by time-temperature superposition displacement based on the scanning data curve.

[0095] Table 3 gives a comparison of the properties of the coatings prepared in the examples and the coatings prepared in the comparative examples.

[0096] Table 3

[0097]

[0098] The above tests confirm that Examples 1-5 all have lower surface free energy, and thus can exhibit excellent antifouling performance. Compared with the comparative examples, the advantage of the present invention is that the examples exhibit excellent bonding effects on a variety of substrates, and can effectively improve the service effect of fouling-release marine antifouling coatings, which is mainly based on the excellent energy dissipation of the coatings caused by the positively charged groups, thereby ensuring strong hydroxyl chemical crosslinking and hydrogen bond interactions.

Claims

1. Modified silicone marine antifouling coatings based on energy dissipation, It is characterized in that In parts by weight, it includes the following components: Modified silicone resin / ethanol mixture 60~100 parts 40~80 parts of pigments and fillers Additives 0~3 parts 100-200 parts of solvent; Wherein, the modified silicone resin / ethanol mixture is prepared by the following steps: (1) In a reaction kettle protected by nitrogen, methyl vinyl MQ type silicone resin, ethanol, monomers having hydroxyl groups and unsaturated groups, cationic monomers, and acrylamide monomers are added in sequence and stirred at 50-150 rpm for 5-15 minutes; (2) Then add azobisisobutyronitrile initiator, keep nitrogen protection, raise the temperature to 50~80℃, and react for 6~12h; (3) The reaction product is washed with acetone in a Soxhlet extractor for 2 to 6 hours, and then dissolved in an equal weight portion of ethanol to obtain a modified silicone resin / ethanol mixture; The cationic monomer is selected from any one of N-(2-acryloyloxyethyl)-N-benzyl-N,N-dimethylammonium chloride, [2-(methacryloyloxy)ethyl]trimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, and trimethylallylammonium chloride.

2. The antifouling coating according to claim 1, It is characterized in that The weight ratio of methyl vinyl MQ type silicone resin, ethanol, monomers having hydroxyl groups and unsaturated groups, cationic monomers, and acrylamide monomers is (50-80): (100-150): (20-30): (5-15): (2-8).

3. The antifouling coating according to claim 1, It is characterized in that The methyl vinyl MQ type silicone resin is selected from those having an M:Q value of ≥1.3:1, or is liquid at 25°C.

4. The antifouling coating according to claim 1, It is characterized in that The monomer having a hydroxyl group and an unsaturated group is selected from any one of 3-(acryloyloxy)-2-hydroxypropyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, methyl 2-(hydroxymethyl)acrylate, and N-hydroxymethyl methacrylamide.

5. The antifouling coating according to claim 1, It is characterized in that The acrylamide monomer is selected from any one of acrylamide, methacrylamide, dimethylaminopropyl acrylamide, N-phenylmethacrylamide and N-tert-butylacrylamide.

6. A method for preparing an antifouling coating according to any one of claims 1 to 5, It is characterized in that The steps include: (1) Add the modified silicone resin / ethanol mixture, additives, and solvent into a stirring and dispersing device in sequence, and stir at 50-200 rpm for 5-10 minutes; (2) Add pigments and fillers into a stirring and dispersing device, increase the speed to 150-300 rpm, and stir for 30-60 minutes; thus, the marine antifouling coating is obtained.

7. A modified silicone marine antifouling coating based on energy dissipation, It is characterized in that The method is obtained by coating the antifouling coating according to any one of claims 1 to 5.

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