Dynamic cross-linked modified fouling release type marine antifouling paint and coating

Abstract

The invention discloses a dynamic cross-linked modified fouling release type marine antifouling paint which is characterized by comprising the following components in parts by weight: 20-50 parts of a component A; 5-10 parts of a component B; 1-4 parts of a component C; wherein the component A comprises hydroxyl-terminated polydimethylsiloxane, an auxiliary agent, a pigment filler and a first solvent; the component B comprises a borate modified curing agent and a second solvent; the component C comprises a catalyst and a third solvent. Based on a modified curing agent with boric acid ester bonds, three-dimensional cross-linking film-forming curing of hydroxyl-terminated polydimethylsiloxane is achieved, the boric acid ester bonds located at three-dimensional cross-linking points are hydrolyzed to release hydrogen bonds, the bonding stability between a coating and an intermediate coat is improved, and the bonding strength between the coating and the intermediate coat is improved. Network chain flexible polysiloxane resin without crosslinking points still endows the coating with excellent low surface energy characteristics, and the antifouling effect of the coating is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical fields of marine antifouling coatings and underwater coating protection, and relates to a dynamically crosslinked modified fouling release marine antifouling coating and coating film. Background Art

[0002] For traditional fouling release silicone marine antifouling coatings, due to the encapsulation of non-polar methyl groups outside the silicone oxygen main chain, the adhesion of the coating film to various polar substrates or intermediate paints is very weak. At the same time, during the seawater immersion process of the applied coating, due to the diffusion of water molecules resulting in water absorption or swelling, and even the hydration layer effect, the adhesion of the coating film will be further weakened, ultimately leading to the shedding of the coating film and affecting the service of such antifouling coatings. Summary of the Invention

[0003] Object of the Invention: The object of the present invention is to provide a dynamically crosslinked modified fouling release marine antifouling coating and coating film, which can ensure that the coating film can serve stably in a seawater environment for a long time without shedding, while still having good low surface free energy.

[0004] Technical Solution: A dynamically crosslinked modified fouling release marine antifouling coating of the present invention, by weight, comprises: (1) 20 - 50 parts of component A; (2) 5 - 10 parts of component B; (3) 1 - 4 parts of component C;

[0005] Wherein,

[0006] Component A, by weight, comprises:

[0007]

[0008] Component B, by weight, comprises:

[0009] Boric acid ester modified curing agent 10 - 30 parts

[0010] Second solvent 20 - 80 parts

[0011] Component C, by weight, comprises:

[0012] Catalyst 5 - 10 parts

[0013] Third solvent 15 - 40 parts.

[0014] The present invention synthesizes a borate-modified curing agent, which can produce a strong hydrogen bonding effect. In the process of coating curing to become a coating, a hydroxyl-terminated polydimethylsiloxane and a borate-modified curing agent react chemically under the action of a catalyst, and finally generate a three-dimensional network structure elastomer. The cross-linking point position of the three-dimensional network structure elastomer is provided by the borate-modified curing agent. Since the functional group that releases the hydrogen bonding effect is located at the cross-linking point position of the flexible silicone three-dimensional network structure, the flexibility and hydrophobicity of the main chain structure will not be affected. In the cross-linking curing process, the group that reacts in the borate-modified curing agent is the methoxysilane group on the curing agent, and the borate-esterified group does not react during the cross-linking process, and still maintains the characteristics of the functional group. Therefore, after curing, the coating generates a strong hydrogen bonding effect from the cross-linking point on the one hand, so that the three-dimensional network structure has a strong adhesiveness, and on the other hand, the network chain of the non-cross-linking point is a flexible, hydrophobic polydimethylsiloxane, so that the coating still has a good low surface free energy, and the anti-fouling effect can be maintained by the way of physical fouling release.

[0015] Preferably, the hydroxyl-terminated polydimethylsiloxane is selected from α,ω-dihydroxy polydimethylsiloxane having a viscosity of 2800 to 10000 mPa·s at 25°C.

[0016] Preferably, the auxiliary agent is selected from at least one of a wetting and dispersing agent, a defoaming agent and a leveling agent.

[0017] Specifically, the wetting and dispersing agent is selected from BYK116, BYK169 of BYK Company, 901, 903 of Deqian Company. The defoaming agent is selected from BYK065, BYK066N of BYK Company, EFKA2020 of Efka of the Netherlands. The leveling agent is selected from BYK308, BYK310, BYK373 of BYK of Germany.

[0018] Preferably, the pigment filler is common in the field, and there is no special requirement. As a further preferred embodiment, it is selected from but not limited to one of calcium carbonate, ferric oxide, titanium dioxide, barium sulfate, kaolin, and zinc oxide.

[0019] Preferably, the first solvent is selected from toluene, xylene and acetone.

[0020] Preferably, the borate modified curing agent is synthesized by free radical copolymerization accompanied by borate cross-linking reaction, and the specific steps are as follows:

[0021] (1) In a reaction kettle under nitrogen protection, boric acid, a monomer with a hydroxypropyl group and an unsaturated group, an acrylate monomer with an ether group, a silane monomer with a (meth)acryloyloxy group, an initiator azobisisobutyronitrile, and a mixed solvent are added in sequence. Then, they are stirred evenly and heated to 65 - 75 °C for reaction for 2 - 6 h;

[0022] (2) Pour the reaction product into methanol at 0 - 8 °C and filter it multiple times. Dissolve the filtered product in ethyl acetate;

[0023] (3) Pour the product / ethyl acetate mixture into an excess of n - hexane at 0 - 8 °C for precipitation, filter and dry it. The obtained precipitate product is the boric acid ester modified curing agent.

[0024] Preferably, the boric acid is selected from those commercially available, with the molecular formula H3BO3, and there is no specific brand or manufacturer requirement.

[0025] Preferably, the monomer with a hydroxypropyl group and an unsaturated group is selected from one of 2 - hydroxy - 1 - methylethyl methacrylate, 1 - hydroxypropyl - 3 - vinylimidazolium bis(trifluoromethanesulfonyl)imide, 2 - hydroxy - 1 - methylethyl acrylate, N - (3 - hydroxypropyl)acrylamide, and 2,3 - dihydroxypropyl acrylate.

[0026] Preferably, the acrylate monomer with an ether group is selected from one of 2 - methoxyethyl acrylate, 1 - allyloxy - 2,3 - epoxypropane, and 2 - (2 - ethoxyethoxy)ethyl acrylate.

[0027] Preferably, the silane monomer with a (meth)acryloyloxy group is selected from one of γ - methacryloyloxypropyltriisopropoxysilane, γ - methacryloyloxypropylmethyldimethoxysilane, and 3 - methacryloxypropyltrimethoxysilane.

[0028] Preferably, the mixed solvent is a mixed solvent that can dissolve the relevant reactants, with no special requirements.

[0029] Specifically, the present invention provides a mixed solvent prepared by mixing acetone, methanol, and ethyl acetate according to a weight ratio of 3:3:4.

[0030] Preferably, the weight ratio of the boric acid, the monomer with a hydroxypropyl group and an unsaturated group, the acrylate monomer with an ether group, the silane monomer with a (meth)acryloyloxy group, the initiator azobisisobutyronitrile, and the mixed solvent is 5:(5 - 10):(2 - 5):(10 - 20):(0.2 - 0.8):(20 - 50).

[0031] Preferably, the second solvent is selected from one of acetone, butanone, and acetylacetone.

[0032] Preferably, the catalyst is selected from one of dibutyltin dilaurate, stannous octoate, and organobismuth.

[0033] Preferably, the third solvent is selected from one of acetylacetone, cyclohexanone, and toluene.

[0034] Preferably, a dynamically crosslinked modified fouling release marine antifouling coating of the present invention can be prepared according to the conventional coating preparation method. First, components A, B, and C are prepared separately and stored sealed.

[0035] Specifically, the present invention provides a specific preparation method, which is not limited to this preparation method in actual application. The specific steps are as follows:

[0036] (1) Hydroxyl-terminated polydimethylsiloxane, additives, and 50% of the first solvent are sequentially added to a dispersion stirring device, and then dispersed at 100 rpm for 20 min. After that, pigments and fillers and 50% of the first solvent are added to the dispersion stirring device and continuously dispersed at the same rotation speed for 20 min to prepare component A, which is then stored sealed;

[0037] (2) Using a dispersion stirring device, disperse the borate-modified curing agent and the second solvent at 50 rpm for 10 min to prepare component B, which is then stored sealed;

[0038] (3) Using a dispersion stirring device, disperse the catalyst and the third solvent at 50 rpm for 10 min to prepare component C, which is then stored sealed;

[0039] Preferably, the present invention also provides a coating prepared from a dynamically crosslinked modified fouling release marine antifouling coating. Components A, B, and C are mixed evenly by conventional dispersion processes and equipment, and are applied by spraying, rolling, brushing, etc. After curing for at least 48 h, a coating with a film thickness of 150 - 250 μm is prepared.

[0040] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages:

[0041] 1. Through free radical polymerization reaction and accompanied by borate crosslinking reaction, a methoxysilane oligomer curing agent with a borate structure is synthesized. This curing agent can then crosslink with hydroxyl-terminated polydimethylsiloxane to form a three-dimensional elastic cured coating.

[0042] 2. In the cured coating, the introduced borate bonds are located at the three-dimensional crosslinking points, so they do not affect the flexibility and hydrophobicity of the three-dimensional network structure segments. The coating still maintains excellent low surface energy characteristics, thus ensuring an effective fouling release antifouling effect.

[0043] 3. During the seawater immersion process, as water molecules diffuse, the borate ester bonds at the crosslinking points can be hydrated, and then hydrolysis can occur, thereby releasing a large amount of hydrogen bonding effects and enhancing the adhesion of the coating during seawater immersion.

[0044] 4. The ether groups introduced in the side chain can also promote the generation of hydrogen bonding effects. The ether groups themselves can form hydrogen bonds with other polar groups. After a large amount of hydrogen bonding effects are released due to the reversible change of the borate ester, the ether groups further strengthen the hydrogen bond effect, thereby ensuring that the coating maintains a lasting, stable, and excellent adhesion effect during seawater immersion. Detailed implementation mode

[0045] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0046] The coating of the present invention realizes the generation of hydrogen bonding effects during seawater immersion by introducing a borate ester dynamic reversible structure, thereby ensuring that the coating has an excellent adhesion effect. At the same time, the introduced borate ester bonds are located at the three-dimensional crosslinking points, so they do not affect the flexibility and hydrophobicity of the three-dimensional network structure segments, and the coating still maintains excellent low surface energy characteristics, thereby ensuring an effective fouling release antifouling effect.

[0047] The raw materials used in the examples are shown in Table 1. During specific implementation, it is not limited to the raw materials in Table 1, and corresponding products can be selected according to the foregoing. Other raw materials used in the examples are all commercially available chemical reagents.

[0048] Table 1

[0049]

[0050]

[0051]

[0052] Preparation of borate ester modified curing agent 1

[0053] Boric acid, monomer 5-1 with hydroxypropyl and unsaturated groups, acrylate monomer 6-1 with ether groups, silane monomer 7-2 with (meth)acryloyloxy group, initiator azobisisobutyronitrile, and mixed solvent are proportioned by weight ratio of 5:8:2:20:0.5:40. The specific preparation process is as follows:

[0054] (1) In a reaction kettle under nitrogen protection, boric acid, a monomer with a hydroxypropyl group and an unsaturated group, an acrylate monomer with an ether group, a silane monomer with a (meth)acryloyloxy group, an initiator azobisisobutyronitrile, and a mixed solvent are added in sequence. Then, it is stirred evenly and heated to 70 °C for reaction for 3 h;

[0055] (2) The reaction product is poured into methanol at 5 °C and filtered multiple times. The filtered product is dissolved in ethyl acetate;

[0056] (3) The product / ethyl acetate mixture is poured into an excess of n-hexane at 0 °C for precipitation, filtered and dried. The obtained precipitated product is the boric acid ester modified curing agent 1.

[0057] Preparation of boric acid ester modified curing agent 2

[0058] Boric acid, a monomer 5-2 with a hydroxypropyl group and an unsaturated group, an acrylate monomer 6-2 with an ether group, a silane monomer 7-1 with a (meth)acryloyloxy group, an initiator azobisisobutyronitrile, and a mixed solvent are proportioned by a weight ratio of 5:5:3:10:0.2:50. The specific preparation process is as follows:

[0059] (1) In a reaction kettle under nitrogen protection, boric acid, a monomer with a hydroxypropyl group and an unsaturated group, an acrylate monomer with an ether group, a silane monomer with a (meth)acryloyloxy group, an initiator azobisisobutyronitrile, and a mixed solvent are added in sequence. Then, it is stirred evenly and heated to 65 °C for reaction for 6 h;

[0060] (2) The reaction product is poured into methanol at 0 °C and filtered multiple times. The filtered product is dissolved in ethyl acetate;

[0061] (3) The product / ethyl acetate mixture is poured into an excess of n-hexane at 5 °C for precipitation, filtered and dried. The obtained precipitated product is the boric acid ester modified curing agent 2.

[0062] Preparation of boric acid ester modified curing agent 3

[0063] Boric acid, a monomer 5-3 with a hydroxypropyl group and an unsaturated group, an acrylate monomer 6-3 with an ether group, a silane monomer 7-1 with a (meth)acryloyloxy group, an initiator azobisisobutyronitrile, and a mixed solvent are proportioned by a weight ratio of 5:10:5:15:0.8:20. The specific preparation process is as follows:

[0064] (1) In a reaction kettle under nitrogen protection, boric acid, a monomer with a hydroxypropyl group and an unsaturated group, an acrylate monomer with an ether group, a silane monomer with a (meth)acryloyloxy group, an initiator azobisisobutyronitrile, and a mixed solvent are added in sequence. Then, it is stirred evenly and heated to 65 °C for reaction for 6 h;

[0065] (2) Pour the reaction product into methanol at 8 °C and filter it several times. Dissolve the filtered product in ethyl acetate.

[0066] (3) Pour the product / ethyl acetate mixture into an excess of n-hexane at 5 °C for precipitation, filter and dry it. The obtained precipitated product is the borate ester modified curing agent 3.

[0067] Examples 1-5

[0068] The component ratios of groups A, B, and C in Examples 1-5 are shown in Table 2, and the component ratios of each component in Examples 1-5 are shown in Table 3.

[0069] Table 2

[0070] Component Example 1 Example 2 Example 3 Example 4 Example 5 A 20 25 50 40 30 B 6 5 10 10 8 C 1.5 1 3 4 4

[0071] Table 3

[0072]

[0073]

[0074] The preparation steps of a dynamically crosslinked modified fouling release marine antifouling coating in Examples 1-5 are as follows. In actual application, it is prepared according to the conventional method of marine antifouling coatings, and is not limited to this preparation method.

[0075] (1) Add hydroxyl-terminated polydimethylsiloxane, additives, and 50% of the first solvent to a dispersion and stirring device in sequence. Then disperse at 100 rpm for 20 min. After that, add pigments and fillers and 50% of the first solvent to the dispersion and stirring device, and continue to disperse at the same rotation speed for 20 min to prepare component A, and then seal and store it.

[0076] (2) Use a dispersion and stirring device to disperse the borate ester modified curing agent and the second solvent at 50 rpm for 10 min to prepare component B, and then seal and store it.

[0077] (3) Use a dispersion and stirring device to disperse the catalyst and the third solvent at 50 rpm for 10 min to prepare component C, and then seal and store it.

[0078] (4) Mix component A, component B, and component C evenly by using a conventional dispersion process and equipment, and apply them by spraying, rolling, brushing, etc. After curing for at least 48 h, prepare a coating with a film thickness of 150-250 μm.

[0079] Comparative Example 1 (Silicone marine antifouling coating without borate ester modified curing agent)

[0080] Compared with Example 1, the curing agent in Comparative Example 1 was not modified with boric acid, and the other components and parts by weight were the same, and its preparation process was also the same as that of Example 1.

[0081] Comparative Example 2 (ordinary silicone low surface energy marine antifouling coating)

[0082] The ordinary silicone low surface energy marine antifouling coating comprises the following raw materials in parts by weight: 90.0 parts of polysiloxane resin, 30.0 parts of pigment and filler, 4.0 parts of crosslinking curing agent, 1.5 parts of catalyst, 0.5 part of auxiliary agent, and 10.0 parts of solvent.

[0083] The polysiloxane resin selects α,ω-dihydroxypolydimethylsiloxane with a viscosity of 10000 mPa·s; the pigment selects zinc oxide; the crosslinking curing agent selects tetraethyl orthosilicate; the catalyst selects dibutyltin dilaurate; the auxiliary agent selects 0.5 part of BYK161 dispersant of BYK Company; the solvent selects xylene.

[0084] (1) Add 90.0 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 10000 mPa·s and 30.0 parts of micron-sized zinc oxide to a disperser, disperse at high speed for 30 min at 300 rpm, and then add 0.5 part of BYK161 dispersant of BYK Company to the disperser at 200 rpm and disperse for 30 min. Then grind it with a sand mill until the fineness is less than 40 μm, make it into a pre-dispersed slurry and store it in a can for later use;

[0085] (2) Mix 4.0 parts of tetraethyl orthosilicate and 10.0 parts of xylene evenly to make a crosslinking curing agent component and store it in a can for later use. Mix 1.5 parts of dibutyltin dilaurate and 20.0 parts of xylene evenly to make a catalyst component and store it in a can for later use;

[0086] (3) Before use, stir the pre-dispersed slurry, crosslinking curing agent component, and catalyst component evenly according to the ratio. The obtained coating is coated and cured to obtain an ordinary silicone low surface energy marine antifouling coating with a thickness of 150-200 μm.

[0087] <Specific test experiments and conditions>

[0088] Test 1: Surface free energy

[0089] Use an XG-CAMC3 type full-automatic contact angle measuring instrument produced by Shanghai Xuanzhun Instrument Co., Ltd. to measure the contact angles of deionized water and diiodomethane on the surface of the cured coating. The surface of the coating needs to be cleaned with anhydrous ethanol and dried before measurement, and then the surface free energy of the coating is calculated according to the Owens two-liquid method.

[0090] Test 2: Measuring adhesion by pull-out method (epoxy intermediate paint)

[0091] The adhesion of the coating applied on the epoxy intermediate paint was measured using a BGD500 digital display semi-automatic adhesion tester produced by Guangzhou Biaogeda Precision Instrument Co., Ltd. Before use, the steel plate was polished with 800-mesh sandpaper. The epoxy intermediate paint used was epoxy micaceous iron oxide intermediate paint produced by Shanghai Jinsi Di. After the epoxy intermediate paint was cured, the coating was applied and the test was carried out after curing. Before testing the adhesion, all coatings were immersed in sterilized seawater for 7 days.

[0092] Test 3: Antifouling performance

[0093] At least 108 units of Streptococcus salivarius were dispersed in 20 mL of tryptic soy broth and cultured at 38 °C in 5% CO2 for 2 hours. Subsequently, the suspension was further diluted and inoculated into agar supplemented with 5% sheep blood and cultured at 38 °C in 5% CO2 for 48 hours. Then, the suspension containing six colony-forming units was dispersed in 10 mL of tryptic soy broth. Subsequently, 20 mL of the above bacterial suspension was spread on the coating in the range of 10×5 cm and cultured at 38 °C in 5% CO2 for 24 hours. After the culture, each sample was 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 substances. The bacteria adhered to the surface were observed using a Simga300 scanning electron microscope produced by Carl Zeiss AG, Germany.

[0094] The specific test results of Examples 1-5 and Comparative Examples 1-2 are shown in Table 4.

[0095] Table 4

[0096]

[0097] Through the above tests, it can be confirmed that the coatings prepared in Examples 1-5 also have a lower surface free energy compared with the coatings of the comparative examples, and thus exhibit excellent antifouling performance. The advantage of the present invention is that the examples have excellent adhesion on the epoxy intermediate paint (polar substrate), which is much stronger than that of the comparative examples, showing excellent bonding effects.

Claims

1. A dynamically crosslinked modified fouling release marine antifouling coating, characterized in that, By weight parts, it includes: 20 - 50 parts of component A; 5 - 10 parts of component B; 1 - 4 parts of component C; Wherein, Component A, by weight parts, includes: Component B, by weight parts, includes: 10 - 30 parts of borate modified curing agent 20 - 80 parts of the second solvent Component C, by weight parts, includes: 5 - 10 parts of catalyst 15 - 40 parts of the third solvent.

2. The dynamically crosslinked modified fouling release marine antifouling coating according to claim 1, wherein, The borate - bonded curing agent is prepared by the following steps: (1) In a reaction kettle under nitrogen protection, boric acid, a monomer with a hydroxypropyl and an unsaturated group, an acrylate monomer with an ether group, a silane monomer with a (meth)acryloyloxy group, an initiator azobisisobutyronitrile, and a mixed solvent are added in sequence, then stirred evenly and heated to 65 - 75 °C for reaction for 2 - 6 h; (2) Pour the reaction product into methanol at 0 - 8 °C and filter multiple times, and dissolve the filtered product in ethyl acetate; (3) Pour the product / ethyl acetate mixture into excessive n - hexane at 0 - 8 °C for precipitation, filter and dry, and the obtained precipitated product is the borate modified curing agent.

3. The dynamically crosslinked modified fouling release marine antifouling coating according to claim 2, wherein, The monomer with a hydroxypropyl and an unsaturated group is selected from one of 2 - hydroxy - 1 - methylethyl methacrylate, 1 - hydroxypropyl - 3 - vinylimidazolium bis(trifluoromethanesulfonyl)imide, 2 - hydroxy - 1 - methylethyl acrylate, N - (3 - hydroxypropyl)acrylamide, 2,3 - dihydroxypropyl acrylate.

4. The dynamically crosslinked modified fouling release marine antifouling coating according to claim 2, wherein The acrylate monomer with an ether group is selected from one of 2 - methoxyethyl acrylate, 1 - allyloxy - 2,3 - epoxypropane, 2 - (2 - ethoxyethoxy)ethyl acrylate.

5. The dynamically crosslinked modified fouling release marine antifouling coating according to claim 2, wherein, The silane monomer with a (meth)acryloyloxy group is selected from one of γ - methacryloyloxypropyltriisopropoxysilane, γ - methacryloyloxypropylmethyldimethoxysilane, 3 - methacryloyloxypropyltrimethoxysilane.

6. The dynamically crosslinked modified fouling release marine antifouling coating according to claim 2, characterized in that, The weight ratio of boric acid, the monomer with a hydroxypropyl and an unsaturated group, the acrylate monomer with an ether group, the silane monomer with a (meth)acryloyloxy group, the initiator azobisisobutyronitrile, and the mixed solvent is 5:(5 - 10):(2 - 5):(10 - 20):(0.2 - 0.8):(20 - 50).

7. The dynamically crosslinked modified fouling release marine antifouling coating according to claim 1, wherein The hydroxyl - terminated polydimethylsiloxane is selected from α,ω - dihydroxypolydimethylsiloxane with a viscosity of 2800 - 10000 mPa·s at 25 °C.

8. The dynamically crosslinked modified fouling release marine antifouling coating according to claim 1, characterized in that, The auxiliary agent is selected from at least one of a wetting and dispersing agent, an antifoaming agent, and a leveling agent.

9. The dynamically crosslinked modified fouling release marine antifouling coating according to claim 1, wherein, The catalyst is selected from one of dibutyltin dilaurate, stannous octoate, and organobismuth.

10. A coating, characterized in that, It is obtained by coating with the state - crosslinked modified fouling - release marine antifouling coating as described in any one of claims 1 - 9.

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