Mucus secreting type polysiloxane marine antifouling paint

Abstract

A thiourea group and a sulfydryl group are introduced into a coating curing agent, the curing agent is endowed with good adhesive force by utilizing a hydrophobic hydrogen bond network effect generated by the thiourea group, and the curing agent is endowed with proper cohesive force by utilizing a folding physical cross-linking effect generated by the sulfydryl group; therefore, the adhesive force and cohesion of the curing agent are coordinated and consistent, and the curing agent is ensured to have an excellent bonding effect. In a final cured coating, firm bonding of the coating and a base material is achieved based on the bonding effect of the curing agent, meanwhile, free non-polar mucus in a three-dimensional network molecular structure of the coating migrates and releases towards the surface of the coating under the influence of a polar curing agent chain segment, the mucus secretion effect is achieved, and therefore it is ensured that the coating has good antifouling performance. The coating can be applied to the field of antifouling of marine facilities, and is particularly suitable for various marine facilities immersed in a seawater environment for a long time.

Description

Technical Field

[0001] The invention belongs to the field of marine antifouling coating technology and underwater coating protection technology, and particularly relates to a functional modified fouling-releasing marine antifouling coating. Background Art

[0002] Marine biofouling refers to the process by which marine fouling organisms non-selectively adhere to and grow on the surface of objects submerged in seawater. It is a major challenge currently faced by countries around the world in developing their ocean and maritime industries. Applying marine antifouling coatings is the most convenient and effective means to solve this problem.

[0003] Traditional marine antifouling coatings, while preventing marine fouling adhesion, bring a lot of pollution and harm, and are now gradually banned by countries around the world. New marine antifouling coatings based on environmentally friendly requirements, while preventing marine fouling organisms, will not threaten the marine environment, and are currently becoming the focus of development in countries around the world.

[0004] Silicone marine antifouling coatings belong to the field of environmentally friendly fouling-releasing antifouling coatings. Based on lower surface free energy and lower elastic modulus, they utilize the relative movement between the ship and the seawater to achieve the prevention and control of fouling organisms and the removal of loosely adhered fouling organisms, and have great application prospects.

[0005] However, silicone marine antifouling coatings currently have shortcomings such as poor adhesion to the substrate and inability to effectively prevent fouling in a static water environment, which urgently need to be improved. At present, bionic studies on large marine organisms such as fish and whales have shown that large marine organisms continuously secrete mucus from the inside out to moisten the skin surface, and use the secreted mucus to wrap and remove adherent fouling organisms. This related bionic mucus secretion type marine antifouling coating developed based on the bionic antifouling mechanism has made beneficial progress. However, this type of mucus secretion type marine antifouling coating generally has the problem of disordered migration and release of bionic mucus, which leads to reduced adhesion between the coating and the substrate. At present, the promotion and use of related coatings are greatly restricted. Summary of the invention

[0006] In view of the shortcomings of poor adhesion between organosilicon low surface energy marine antifouling coating and substrate, and the need for seawater flushing to achieve good antifouling, the present invention provides a mucus secretion type polysiloxane marine antifouling coating, synthesizes a modified curing agent through Michael addition reaction, introduces thiourea group and mercapto group into the molecular structure of the curing agent, and uses the hydrophobic hydrogen bond network effect generated by the thiourea group to give the curing agent good adhesion, and uses the folding physical cross-linking effect generated by the mercapto group to give the curing agent suitable cohesion, so that the adhesion and cohesion of the curing agent are coordinated and consistent, ensuring that the curing agent has excellent bonding effect. In the final cured coating, the coating and the substrate are firmly bonded based on the bonding effect of the curing agent, and at the same time, the free non-polar mucus inside the three-dimensional network molecular structure of the coating migrates and releases to the coating surface under the influence of the polar curing agent chain segment, achieving the mucus secretion effect, thereby ensuring that the coating has good antifouling performance.

[0007] The present invention is implemented by the following technical solutions:

[0008] In a first aspect, the present invention provides a mucus secretion type polysiloxane marine antifouling coating, which comprises, by weight: (1) 80 to 100 parts of component A; (2) 8 to 20 parts of component B; (3) 5 to 10 parts of component C;

[0009] in,

[0010] Component A includes by weight:

[0011]

[0012] Component B includes by weight:

[0013] Modified curing agent 10-30 parts

[0014] Solvent B 20-40 parts;

[0015] Component C includes by weight:

[0016] 1 to 4 parts of catalyst

[0017] Solvent C 5-20 parts;

[0018] The modified curing agent is prepared by the following steps:

[0019] (1) In a reaction device protected by nitrogen and equipped with a stirring and reflux device, a thiourea compound with an unsaturated group, a mercapto ester monomer, a curing agent, an amine catalyst, and dichloromethane are added in sequence, and then stirred at 20 to 35° C. and 50 to 100 rpm for 6 to 14 hours;

[0020] (2) The product after the reaction is filtered and precipitated, and washed with dichloromethane at least 3 times, then the precipitated product is obtained by filtration, and dried in a vacuum device for 24 hours to finally obtain a modified curing agent.

[0021] Preferably, the weight ratio of the thiourea compound with an unsaturated group, the mercapto ester monomer, the curing agent, the amine catalyst, and dichloromethane is (1-5): (5-12): (10-20): (1-3): (50-100).

[0022] Preferably, the thiourea compound with an unsaturated group is selected from one of N-allylthiourea, N-propylene N'-2-hydroxyethylthiourea, 4-(3-allylthiourea)benzoic acid, 4-propylenethioamine urea, and 1-allyl-3-(pyridin-2-yl)thiourea.

[0023] Preferably, the mercapto ester monomer is selected from one of 3-mercaptopropionate, trimethylolpropane tris(3-mercaptopropionate), 2-ethylhexyl 3-mercaptopropionate and isooctyl 3-mercaptopropionate.

[0024] Preferably, the curing agent is selected from one of 3-(methacryloyloxy)propyltrimethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane, γ-methacryloyloxypropyltriisopropoxysilane and γ-methacryloyloxypropylmethyldimethoxysilane.

[0025] Preferably, the amine catalyst is selected from one of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether and N,N,N',N'-tetramethylalkylenediamine.

[0026] Preferably, the non-polar mucus is selected from non-reactive inert silicone oil.

[0027] Specifically, the non-reactive inert silicone oil is selected from methyl silicone oil with a kinematic viscosity of 10 to 50 cSt at room temperature, phenyl methyl silicone oil with a kinematic viscosity of 50 to 200 cSt at room temperature, and alkyl silicone oil with a kinematic viscosity of 70 to 100 cSt at room temperature.

[0028] Preferably, the hydrophobic silicone resin is selected from α,ω-dihydroxypolydimethylsiloxane having a viscosity of 2800-10000 mPa·s at 25°C.

[0029] Preferably, the auxiliary agent is selected from at least one of a wetting and dispersing agent, a defoaming agent and a leveling agent.

[0030] Specifically, the wetting and dispersing agent is selected from BYK116, BYK169 of BYK Company, and 901, 903 of Deqian Company.

[0031] Specifically, the defoaming agent is selected from BYK065, BYK066N of BYK and EFKA2020 of EFKA of the Netherlands.

[0032] Specifically, the leveling agent is selected from one of German BYK308, BYK310 and BYK373.

[0033] Preferably, the pigment filler is common in the field, and there is no special requirement. As a preferred embodiment, it is selected from but not limited to one of calcium carbonate, ferric oxide, titanium dioxide, barium sulfate, kaolin, and zinc oxide.

[0034] Preferably, the solvent A is selected from one of methanol, xylene and acetone.

[0035] Preferably, the solvent B is selected from one of acetone, butanone and acetylacetone.

[0036] Preferably, the catalyst is selected from dibutyltin dilaurate, stannous octoate, and organic bismuth.

[0037] Preferably, the solvent C is selected from one of acetylacetone, cyclohexanone and toluene.

[0038] In a second aspect, the present invention further provides a method for preparing the coating according to the first aspect, which is prepared according to a conventional preparation method, wherein component A, component B, and component C are prepared separately and sealed and stored, and specifically comprises the following steps:

[0039] (1) Adding a hydrophobic silicone resin, an additive, and a non-polar mucus to a dispersing and stirring device in sequence, and then dispersing at 100 rpm for 20 min, then adding a pigment, a filler, and a solvent A to the dispersing and stirring device, and continuing to disperse at the same speed for 20 min, i.e., preparing component A, and then sealing and storing;

[0040] (2) using a dispersing and stirring device to disperse the modified curing agent and solvent B at 50 rpm for 10 min, i.e., preparing component B, and then sealing and storing;

[0041] (3) Using a dispersing and stirring device at 50 rpm, the catalyst and solvent C were dispersed for 10 min to prepare component C, which was then sealed and stored.

[0042] In the third aspect, the present invention also provides an antifouling coating prepared by the coating described in the first aspect, wherein component A, component B, and component C are evenly mixed using conventional dispersion processes and equipment, and applied by spraying, rolling, brushing, etc., and cured for at least 48 hours to prepare a coating with a film thickness of 150 to 250 um.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The modified curing agent is synthesized by Michael addition reaction, and the thiourea group and the mercapto group are introduced into the molecular structure of the curing agent. The hydrophobic hydrogen bond network generated by the thiourea group is used to give the curing agent good adhesion, and the folding physical cross-linking effect generated by the mercapto group is used to give the curing agent suitable cohesion, so that the adhesion and cohesion of the curing agent are coordinated, ensuring that the curing agent has excellent bonding effect.

[0045] 2. In the final cured coating, the uniformly distributed curing agent structure gives the cured coating a beneficial bonding effect, which can firmly bond to the substrate and the intermediate paint surface. At the same time, as a curing agent molecular structure, it will not affect the main film-forming polysiloxane molecular structure of the coating, ensuring that the cured coating still has excellent softness and low surface energy properties.

[0046] 3. The polar groups (mainly thiol groups) brought by the modified curing agent can be used to drive the non-polar mucus in the free state in the cured coating to migrate and release to the coating surface, thereby simulating the anti-fouling properties of mucus secretion, ensuring that the coating still has active physical anti-fouling properties even in the absence of high-speed seawater scouring conditions, thereby ensuring the beneficial anti-fouling performance of the coating.

[0047] 4. The cured coating and substrate or intermediate paint achieve strong adhesion through hydrogen bond network, and at the same time inhibit the migration of non-polar adhesive to the coating-substrate area, thereby ensuring that the non-polar adhesive can only migrate and release to the coating surface. DETAILED DESCRIPTION

[0048] 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 be made. These all belong to the protection scope of the present invention.

[0049] The coating of the present invention, on the one hand, utilizes the modified curing with thiourea groups and mercapto groups to ensure that the cured coating can firmly bind mucus, and on the other hand, non-polar mucus cannot be stably stored inside the coating, and is driven by the molecular structure of the polar curing agent to migrate and release to the surface of the coating, thereby achieving good physical anti-fouling properties in the absence of high-speed seawater scouring conditions.

[0050] 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.

[0051] Table 1

[0052]

[0053] Modified curing agent 1

[0054] The weight ratio of the thiourea compound with unsaturated groups, the mercapto ester monomer, the curing agent, the amine catalyst, and dichloromethane is 5:10:20:2:60. The specific preparation steps are as follows:

[0055] (1) In a reaction device protected by nitrogen and equipped with a stirring reflux device, thiourea compound 6-1 having an unsaturated group, mercapto ester monomer 7-1, curing agent 8-2, amine catalyst 9-1, and dichloromethane are added in sequence, and then stirred at 80 rpm at 25° C. for 10 hours;

[0056] (2) The product after the reaction was filtered and precipitated, and washed with dichloromethane at least 3 times, then the precipitated product was obtained by filtration, and dried in a vacuum device for 24 hours to finally obtain the modified curing agent 1.

[0057] Modified curing agent 2

[0058] The weight ratio of the thiourea compound with unsaturated groups, the mercapto ester monomer, the curing agent, the amine catalyst, and dichloromethane is 1:5:15:1:50. The specific preparation steps are as follows:

[0059] (1) In a reaction device protected by nitrogen and equipped with a stirring reflux device, a thiourea compound 6-2 having an unsaturated group, a mercapto ester monomer 7-2, a curing agent 8-1, an amine catalyst 9-2, and dichloromethane are added in sequence, and then stirred at 20° C. and 100 rpm for 6 hours;

[0060] (2) The product after the reaction was filtered and precipitated, and washed with dichloromethane at least 3 times, then the precipitated product was obtained by filtration, and dried in a vacuum device for 24 hours to finally obtain the modified curing agent 2.

[0061] Modified curing agent 3

[0062] The weight ratio of the thiourea compound with unsaturated groups, the mercapto ester monomer, the curing agent, the amine catalyst, and dichloromethane is 3:12:10:3:100. The specific preparation steps are as follows:

[0063] (1) In a reaction device protected by nitrogen and equipped with a stirring reflux device, a thiourea compound 6-3 having an unsaturated group, a mercapto ester monomer 7-2, a curing agent 8-3, an amine catalyst 9-2, and dichloromethane are added in sequence, and then stirred at 35° C. and 50 rpm for 14 hours;

[0064] (2) The product after the reaction was filtered and precipitated, and washed with dichloromethane at least 3 times, then the precipitated product was obtained by filtration, and dried in a vacuum device for 24 hours to finally obtain the modified curing agent 3.

[0065] Examples 1-5

[0066] The proportions of the three components A, B, and C of Examples 1-5 are shown in Table 2, and the specific proportions of the components of Examples 1-5 are shown in Table 3.

[0067] Table 2

[0068] Components Example 1 Example 2 Example 3 Example 4 Example 5 A 70 100 80 70 90 B 10 15 20 15 12 C 5 8 10 10 8

[0069] Table 3

[0070]

[0071] According to Table 2 and Table 3, the preparation method of the mucus secretion type polysiloxane marine antifouling coating of Examples 1-5 is shown in the following steps:

[0072] (1) Adding a hydrophobic silicone resin, an additive, and a non-polar mucus to a dispersing and stirring device in sequence, and then dispersing at 100 rpm for 20 min, then adding a pigment, a filler, and a solvent A to the dispersing and stirring device, and continuing to disperse at the same speed for 20 min, i.e., preparing component A, and then sealing and storing;

[0073] (2) using a dispersing and stirring device to disperse the modified curing agent and solvent B at 50 rpm for 10 min, i.e., preparing component B, and then sealing and storing;

[0074] (3) using a dispersing and stirring device to disperse the catalyst and solvent C at 50 rpm for 10 min, i.e., preparing component C, and then sealing and storing;

[0075] (4) Component A, component B, and component C are mixed uniformly using conventional dispersion processes and equipment, and applied by spraying, rolling, brushing, etc. After curing for at least 48 hours, a coating with a film thickness of 150 to 250 μm is prepared.

[0076] In actual application, the antifouling coating can be prepared by conventional methods of marine antifouling coatings, and is not limited to the above preparation method.

[0077] Comparative Example 1 (Ordinary silicone low surface energy marine antifouling coating)

[0078] 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 10.0 parts of third solvent.

[0079] 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 third solvent is xylene.

[0080] (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.

[0081] (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;

[0082] (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 250 μm is obtained.

[0083] Comparative Example 2

[0084] Compared with Example 1, no mercapto ester monomer is introduced into the prepared modified curing agent, the remaining components and their weight parts are the same, and the preparation process is also the same as that of Example 1.

[0085] <Specific test experiments and conditions>

[0086] Test 1: Pull-off method to measure adhesion after 100 days of seawater immersion (steel plate, epoxy intermediate paint)

[0087] 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 needs to be polished with 800-grit sandpaper before use, and the epoxy intermediate paint used is the epoxy micaceous iron intermediate paint produced by Shanghai Jinsi Di. Before the test, it needs to be immersed in sterilized seawater for 100 days, and then taken out and dried for testing.

[0088] Test 2: Antifouling performance

[0089] 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.

[0090] The specific test results of Examples 1-5 and Comparative Examples 1-2 are shown in Table 4.

[0091] Table 4

[0092]

[0093] The above tests confirm that the coatings of the examples and the comparative examples have lower surface free energy, thus exhibiting excellent antifouling performance. The advantage of the present invention is that the examples have excellent adhesion on various polar substrates, which is much stronger than the comparative examples, and exhibits excellent bonding effect.

[0094] The above is a description of the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A mucus secretion type polysiloxane marine antifouling coating, characterized in that: In parts by weight, it comprises: (1) 80 to 100 parts of component A; (2) 8 to 20 parts of component B; (3) 5 to 10 parts of component C; in, Component A includes by weight: Component B includes by weight: Modified curing agent 10-30 parts Solvent B 20-40 parts; Component C includes by weight: 1 to 4 parts of catalyst Solvent C 5-20 parts; The modified curing agent is prepared by the following steps: (1) In a reaction device protected by nitrogen and equipped with a stirring and reflux device, a thiourea compound with an unsaturated group, a mercapto ester monomer, a curing agent, an amine catalyst, and dichloromethane are added in sequence, and then stirred at 20 to 35° C. and 50 to 100 rpm for 6 to 14 hours; (2) The product after the reaction was filtered and precipitated, and washed with dichloromethane at least three times, and then the precipitated product was obtained by filtration, and dried in a vacuum device for 24 hours to obtain a modified curing agent.

2. The antifouling coating according to claim 1, characterized in that The weight ratio of the thiourea compound with unsaturated groups, the mercapto ester monomer, the curing agent, the amine catalyst and the dichloromethane is (1-5): (5-12): (10-20): (1-3): (50-100).

3. The antifouling coating according to claim 1, characterized in that The thiourea compound with an unsaturated group is selected from one of N-allylthiourea, N-propylene N'-2-hydroxyethylthiourea, 4-(3-allylthiourea)benzoic acid, 4-propylenethioamine urea, and 1-allyl-3-(pyridin-2-yl)thiourea.

4. The antifouling coating according to claim 1, characterized in that The mercapto ester monomer is selected from one of 3-mercaptopropionate, trimethylolpropane tris(3-mercaptopropionate), 2-ethylhexyl 3-mercaptopropionate and isooctyl 3-mercaptopropionate.

5. The antifouling coating according to claim 1, characterized in that: The curing agent is selected from one of 3-(methacryloyloxy)propyltrimethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane, γ-methacryloyloxypropyltriisopropoxysilane and γ-methacryloyloxypropylmethyldimethoxysilane.

6. The antifouling coating according to claim 1, characterized in that: The amine catalyst is selected from one of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether and N,N,N',N'-tetramethylalkylenediamine.

7. The antifouling coating according to claim 1, characterized in that: The non-polar mucus is selected from non-reactive, inert silicone oils.

8. The antifouling coating according to claim 1, characterized in that: The non-reactive inert silicone oil is selected from methyl silicone oil with a kinematic viscosity of 10 to 50 cSt at room temperature, phenyl methyl silicone oil with a kinematic viscosity of 50 to 200 cSt at room temperature, and alkyl silicone oil with a kinematic viscosity of 70 to 100 cSt at room temperature.

9. The method for preparing the antifouling coating according to any one of claims 1 to 8, characterized in that: The steps include: (1) Adding a hydrophobic silicone resin, an additive, and a non-polar mucus to a dispersing and stirring device in sequence, and then dispersing at 100 rpm for 20 min, then adding a pigment, a filler, and a solvent A to the dispersing and stirring device, and continuing to disperse at the same speed for 20 min, i.e., preparing component A, and then sealing and storing; (2) using a dispersing and stirring device to disperse the modified curing agent and solvent B at 50 rpm for 10 min, i.e., preparing component B, and then sealing and storing; (3) Using a dispersing and stirring device at 50 rpm, the catalyst and solvent C were dispersed for 10 min to prepare component C, which was then sealed and stored.

10. The antifouling coating prepared by the antifouling coating according to any one of claims 1 to 8, characterized in that: Component A, component B and component C are mixed evenly, applied on the substrate, and cured for at least 48 hours to prepare a coating with a film thickness of 150 to 250 um.

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