Mussel-imitating anti-corrosion and anti-fouling integrated resin and preparation method thereof

Abstract

The invention relates to the technical field of polymer composite materials, in particular to mussel-imitating anti-corrosion and anti-fouling integrated resin and a preparation method thereof. The preparation method comprises the following steps: firstly, carrying out addition reaction on unsaturated C = C double bonds on a long side chain of urushiol and hydrogen-terminated polydimethylsiloxane under the action of a catalyst to prepare organic silicon modified urushiol; then, blending the organic silicon modified urushiol with epoxy resin to prepare organic silicon-containing urushiol modified epoxy resin; and finally, cooling the urushiol modified epoxy resin containing organic silicon to room temperature, adding a stoichiometric curing agent, coating on the surface of a base material, and curing at normal temperature or heating to form a film. The spontaneous gradient layering effect in the curing process is achieved through molecular structure design, an anti-corrosion barrier layer and a low-surface-energy anti-fouling active surface can be synchronously constructed in a single coating system, and an innovative solution with engineering economy and environment compliance is provided for ship whole-life-cycle maintenance.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, and in particular to a mussel-inspired anti-corrosion and anti-fouling integrated resin and its preparation method. Background Technology

[0002] The synergistic effect of electrochemical corrosion and biofouling on metal structures in the underwater marine environment constitutes a highly destructive dual erosion effect. According to the International Shipping Association (ISA), this damage results in over $50 billion in direct economic losses annually for the global shipping industry, significantly increasing the risk of structural failure and biological invasion. Among existing protective technologies, composite functional coating systems remain the most valuable approach for engineering applications due to their designability and engineering applicability. However, the current mainstream three-layer coating system—"anti-corrosion primer-intermediate binder-antifouling topcoat"—not only suffers from complex coating procedures and long curing times between layers, but also generates substantial volatile organic compound (VOC) emissions due to its high organic solvent content (35%-45%). Particularly noteworthy is that approximately 60% of the system's total life-cycle cost comes from the coating application stage, posing a dual challenge in terms of environmental friendliness and long-term protective performance.

[0003] Epoxy resins dominate the corrosion protection field due to their superior mechanical properties and interfacial adhesion. However, their inherent hydrophilicity leads to interfacial water permeation, causing water molecule-mediated coating swelling that disrupts the molecular cross-linking network, enriching interfacial hydroxyl groups to form electrolyte channels, and creating a dynamic electrical double layer at the metal matrix / resin interface. These synergistic effects shorten the effective protection period of traditional epoxy systems in marine environments to less than 3 years, significantly lower than the design life requirement.

[0004] Therefore, those skilled in the art urgently need a coating that is simple to process, has both corrosion and antifouling properties, and excellent environmental performance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing an integrated anti-corrosion and anti-fouling resin similar to that used for mussels, comprising the following steps: S1. Add urushiol, hydrogen-terminated polydimethylsiloxane, diluent and catalyst to a reaction vessel, heat and reflux under an inert gas atmosphere to carry out the reaction; after the reaction is completed, perform vacuum distillation to remove the diluent and obtain organosilicon-modified urushiol. S2. Add the organosilicon-modified urushiol, epoxy resin, and diluent obtained in S1 to the reaction vessel, heat and reflux the mixture while stirring, mix thoroughly, and then perform vacuum distillation to remove the diluent, thereby obtaining organosilicon-modified epoxy resin. S3. Cool the silicone-containing urushiol-modified epoxy resin obtained in step 2 to room temperature, add a curing agent, stir evenly, coat it on the substrate surface, and cure it into a film to obtain the integrated resin with mussel-like anti-corrosion and anti-fouling properties.

[0006] In one embodiment, the amount of urushiol used is 0.1%-15% of the total resin mass, the amount of hydrogen-terminated polydimethylsiloxane used is 0.01%-3% of the total resin mass, and the sum of the amounts of epoxy resin and curing agent used is 82%-99.89% of the total resin mass. The amounts of curing agent and epoxy resin used are chemically equivalent.

[0007] It is understood that the amount of epoxy resin added is matched with the stoichiometry of the epoxy resin, that is, the total equivalent number of epoxy groups in the epoxy resin is equal to the total equivalent number of active hydrogens in the curing agent.

[0008] In one embodiment, the catalyst is one or more of platinum, cobalt, palladium, nickel, and rhodium.

[0009] Preferably, the catalyst is a KARSTEDT catalyst.

[0010] In one embodiment, the epoxy resin is one or more of glycidyl ether epoxy resin, glycidyl ester epoxy resin, and non-glycidyl epoxy resin.

[0011] In one embodiment, the diluent is one or more of tetrahydrofuran, toluene, xylene, isopropanol, cyclohexanone, and ethylene glycol dimethyl ether.

[0012] In one embodiment, the curing agent is one or more of amine curing agents, acid anhydride curing agents, and synthetic resin curing agents.

[0013] Preferably, the curing agent is polyetheramine D-400.

[0014] In one embodiment, the amount of catalyst used is 1%-2% of the total mass of urushiol and hydrogen-terminated polydimethylsiloxane.

[0015] In one embodiment, the reaction temperature in step S1 is 90-100°C and the reaction time is 2-3 h; the reaction temperature in step S2 is 60-90°C.

[0016] In one embodiment, the substrate in step S3 is carbon steel or aluminum alloy.

[0017] The present invention also provides an integrated anti-corrosion and anti-fouling resin for imitation mussels, which is prepared by the preparation method of the integrated anti-corrosion and anti-fouling resin for imitation mussels as described above.

[0018] Compared with existing technologies, the preparation method of the mussel-inspired anti-corrosion and antifouling integrated resin provided by this invention involves the hydrosilylation reaction of urushiol with hydrogen-terminated polydimethylsiloxane to form organosilicon-modified urushiol. This method retains the strong adhesive properties of the catechol groups of urushiol (imitating the underwater adhesion characteristics of mussels) while introducing low surface energy segments of organosilicon to impart antifouling capabilities. When this modified product is blended with epoxy resin, phase separation is avoided due to structural compatibility, and a dense network is synergistically formed to enhance the anti-corrosion barrier ability. The curing agent cross-links and cures the epoxy resin to form a film, while simultaneously promoting the migration of organosilicon segments to the surface, spontaneously forming a gradient structure of bottom-layer anti-corrosion barrier and surface antifouling. Highly efficient anti-corrosion and antifouling can be achieved simultaneously without multiple coatings, forming an integrated anti-corrosion and antifouling resin with low surface energy characteristics. This can serve as the basis for further constructing anti-corrosion and antifouling coating systems that meet the conditions of marine engineering applications. Furthermore, the removal of diluents achieves solvent-free production, reducing VOC emissions while achieving excellent performance balance with low component dosage, solving the problems of single function and complex construction of traditional coatings. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 Nyquist plot of the resins used in the embodiments and comparative examples of this invention after soaking in a 3.5% NaCl solution for 30 days; Figure 2 Bode plots of the resins used in the embodiments and comparative examples of this invention after soaking in a 3.5% NaCl solution for 30 days; Figure 3 Resin surface contact angle diagrams provided for embodiments and comparative examples of the present invention; Figure 4 Adhesion diagrams of resins on carbon steel surfaces in embodiments and comparative examples provided by the present invention; Figure 5 The images show the fouling of resins on the surface of *Navicula* under dynamic water flow conditions, as provided in the embodiments and comparative examples of this invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] To provide a coating that is simple to process, has both corrosion resistance and antifouling properties, and is environmentally friendly, the present invention provides the following embodiments and comparative examples.

[0023] Example 1 Example 1 provides a mussel-inspired anti-corrosion and anti-fouling integrated resin, the specific preparation steps of which are as follows: S1. 1.6 g of urushiol, 0.067 g of hydrogen-terminated polydimethylsiloxane with an average molecular weight of 580, and 20 ml of anhydrous tetrahydrofuran were added to a three-necked flask and stirred until homogeneous. Then, an appropriate KARSTEDT catalyst was added, and the mixture was heated to 90 °C and refluxed under inert gas protection for 2 h. After the reaction was completed, the tetrahydrofuran was removed by vacuum distillation to obtain organosilicon-modified urushiol. S2. Add 10 g of epoxy resin E51 to the above-mentioned organosilicon-modified epoxy resin, and add 20 ml of toluene as a solvent. Heat and reflux at 90°C, stir until uniform, and after the reaction is complete, remove toluene by vacuum distillation to obtain urushiol-modified epoxy resin containing organosilicon, and cool to room temperature. S3. Based on chemical equivalent calculations, 5.1 g of polyetheramine D-400 was added to the silicone-containing urushiol-modified epoxy resin, which had been cooled to room temperature, as a curing agent. After stirring evenly, the mixture was applied to the carbon steel surface with a wet film thickness of 100 μm. S4. Place the resin-coated carbon steel in an oven and cure it at 90°C for 3 hours. Then, remove it and store it at room temperature for 7 days to allow the resin to fully cure, thus obtaining a mussel-like anti-corrosion and anti-fouling integrated resin with a cured film thickness of 100 μm ± 10 μm.

[0024] Example 2 Example 2 provides a mussel-inspired anti-corrosion and anti-fouling integrated resin, the specific preparation steps of which are as follows: S1. 0.8 g of urushiol, 0.033 g of hydrogen-terminated polydimethylsiloxane with an average molecular weight of 580, and 20 ml of anhydrous tetrahydrofuran were added to a three-necked flask and stirred until homogeneous. Then, an appropriate KARSTEDT catalyst was added, and the mixture was heated to 90 °C and refluxed under inert gas protection for 2 h. After the reaction was completed, the tetrahydrofuran was removed by vacuum distillation to obtain organosilicon-modified urushiol. S2. Add 10 g of epoxy resin E51 to the above-mentioned organosilicon-modified epoxy resin, and add 20 ml of toluene as a solvent. Heat and reflux at 90°C, and stir until homogeneous. After the reaction is complete, remove the toluene by vacuum distillation to obtain urushiol-modified epoxy resin containing organosilicon, and cool to room temperature. S3. Based on chemical equivalent calculations, 5.1 g of polyetheramine D-400 was added to the silicone-containing urushiol-modified epoxy resin, which had been cooled to room temperature, as a curing agent. After stirring evenly, the mixture was applied to the carbon steel surface with a wet film thickness of 100 μm. S4. Place the resin-coated carbon steel in an oven and cure it at 90°C for 3 hours. Then, remove it and store it at room temperature for 7 days to allow the resin to fully cure, thus obtaining a mussel-like anti-corrosion and anti-fouling integrated resin with a cured film thickness of 100 μm ± 10 μm.

[0025] Comparative Example 1 Comparative Example 1 involves directly adding epoxy resin E51 to a curing agent to form a film. The specific preparation steps are as follows: S1. Add 10 g of epoxy resin E51 and 5.1 g of polyetheramine D-400 to a beaker, stir evenly, and then coat it on the carbon steel surface to achieve a wet film thickness of 100 μm. S2. Place the carbon steel coated with resin in an oven and cure it at 90°C for 3 hours. Then take it out and store it at room temperature for 7 days to allow the resin to fully cure, thus obtaining epoxy resin with a film thickness of 100 μm ± 10 μm.

[0026] Comparative Example 2 Comparative Example 2 involved modifying epoxy resin E51 with urushiol, then adding a curing agent and curing it into a film. The specific preparation steps are as follows: S1. Add 1.6 g of urushiol and 10 g of epoxy resin E51 to a three-necked flask, add 20 ml of toluene as a solvent, heat and reflux, and mix thoroughly; after the reaction is complete, remove toluene by vacuum distillation to obtain urushiol-modified epoxy resin, and cool to room temperature. S2. Based on chemical equivalent calculations, 5.1 g of polyetheramine D-400 was added to the urushiol-modified epoxy resin cooled to room temperature as a curing agent. After stirring evenly, it was coated on the carbon steel surface with a wet film thickness of 100 μm. S3. Place the resin-coated carbon steel in an oven and cure it at 90°C for 3 hours. Then remove it and store it at room temperature for 7 days to allow the resin to fully cure, thus obtaining urushiol-modified epoxy resin with a cured film thickness of 100 μm ± 10 μm.

[0027] Performance testing 1. Electrochemical Impedance Spectroscopy (EIS) Measurement: A three-electrode system immersed in 3.5 wt% NaCl solution was used at room temperature. The experiment was conducted on a CS2350M electrochemical workstation (Wuhan KOST Instrument Co., Ltd.), with a frequency range of 10 Hz. 5 Hz to 10 -2 A sinusoidal disturbance with an amplitude of 30 mV at an open-circuit potential; Hz; The electrochemical cell structure includes: a prepared coating (exposed area = 1.0 cm²) as the working electrode, a platinum (Pt) wire as the counter electrode, and a saturated Ag / AgCl electrode as the reference electrode. Test results are shown in […]. Figure 1-2 .

[0028] 2. Surface Contact Angle Test: The contact angle was measured in a natural environment using an optical contact angle meter (Dataphysics OCA 15EC, Germany). The deionized water droplet method was used, with a drop volume of 3 μL. The test results are shown below. Figure 3 .

[0029] 3. Adhesion test on carbon steel surface: The adhesion of the samples was tested using a Defelsko PosiTest AT-A pull-out adhesion tester. The test results are shown in […]. Figure 4 .

[0030] 4. Fouling experiment of *Novoidea* on the surface under dynamic water flow environment: A self-made laboratory dynamic biofouling system was used. Specific testing methods are detailed in patent publication number CN108627618A. *Novoidea* was selected as the target for biofouling experiments in Comparative Examples 1-2 and Examples 1-2. The test results are shown in […]. Figure 5 .

[0031] Results Analysis like Figure 1 and Figure 2 As shown, after soaking in a 3.5% NaCl solution for 30 days, |Z| of Comparative Example 1... 0.01 Hz =4.51 × 10 9 Ω·cm 2 Comparative example 2 |Z| 0.01 Hz = 5.41 × 10 9 Ω·cm 2 |Z| in Example 1 0.01 Hz =6.91 × 10 9 Ω·cm 2 |Z| in Example 2 0.01 Hz = 6.50 × 10 9 Ω·cm 2 , Compared to Comparative Examples 1 and 2, the |Z| of Example 1 0.01 HzThe increases were 53.21% and 27.73% respectively, in Example 2, |Z| 0.01 Hz These figures represent increases of 44.12% and 20.15%, respectively.

[0032] like Figure 3 The water contact angle of Comparative Example 1 is 86°±1.3°, the water contact angle of Comparative Example 2 is 95°±1.2°, the water contact angle of Example 1 is 103°±1.7°, and the water contact angle of Example 2 is 102°±1.6°. Compared with Comparative Example 1 and Comparative Example 2, the contact angles of Example 1 and Example 2 are significantly improved, and the hydrophobicity is significantly improved.

[0033] like Figure 4 As shown, the adhesion of Comparative Example 1 to the carbon steel surface was 6.44 MPa ± 0.93 MPa, the adhesion of Comparative Example 2 to the carbon steel surface was 10.81 MPa ± 1.54 MPa, the adhesion of Example 1 to the carbon steel surface was 9.87 MPa ± 0.91 MPa, and the adhesion of Example 2 to the carbon steel surface was 9.93 MPa ± 1.14 MPa. Due to the introduction of urushiol, the adhesion of Comparative Example 2 was significantly improved compared to Comparative Example 1. The addition of less silicone resin in Examples 1 and 2 resulted in a slight decrease in adhesion compared to Comparative Example 2, but it was still significantly improved compared to Comparative Example 1. At the same time, the hydrophobicity was significantly improved.

[0034] like Figure 5 As shown, the coverage rate of *Navicula* in Comparative Example 1 was 7.65% ± 1.34%, the coverage rate of *Navicula* in Comparative Example 2 was 7.32% ± 1.64%, the coverage rate of *Navicula* in Example 1 was 3.73% ± 0.71%, and the coverage rate of *Navicula* in Example 2 was 4.03% ± 0.92%. There was no significant difference in the coverage rate of *Navicula* between Comparative Example 1 and Comparative Example 2. The coverage rates of Examples 1 and 2 were significantly lower than those of Comparative Example 1 and Comparative Example 2, demonstrating better antifouling effects.

[0035] In summary, this invention provides a solvent-free mussel-inspired integrated anti-corrosion and antifouling resin and its preparation method. The resin is synthesized from epoxy resin, urushiol, hydrogen-terminated polydimethylsiloxane, diluent, catalyst, and epoxy resin curing agent. The preparation method first utilizes the unsaturated C=C double bonds on the long side chains of urushiol to undergo an addition reaction with hydrogen-terminated polydimethylsiloxane under the action of a catalyst to prepare organosilicon-modified urushiol. Then, the organosilicon-modified urushiol is blended with epoxy resin to prepare an organosilicon-containing urushiol-modified epoxy resin. Finally, the organosilicon-containing urushiol-modified epoxy resin is cooled to room temperature, a stoichiometric amount of curing agent is added, and the mixture is coated onto the substrate surface and cured at room temperature or by heating to form a film. This invention achieves a spontaneous gradient stratification effect during the curing process through molecular structure design, enabling the simultaneous construction of an anti-corrosion barrier layer and a low surface energy antifouling active surface in a single coating system. This provides an innovative solution for the life-cycle maintenance of ships that combines engineering economy and environmental compliance.

[0036] Although terms such as urushiol, hydrogen-terminated polydimethylsiloxane, diluent, silicone-modified urushiol, and epoxy resin are frequently used herein, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would be contrary to the spirit of the invention.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an integrated anti-corrosion and anti-fouling resin mimicking mussels, characterized in that, Includes the following steps: S1. Add urushiol, hydrogen-terminated polydimethylsiloxane, diluent and catalyst to a reaction vessel, heat and reflux under an inert gas atmosphere to carry out the reaction; after the reaction is completed, perform vacuum distillation to remove the diluent and obtain organosilicon-modified urushiol. S2. Add the organosilicon-modified urushiol, epoxy resin, and diluent obtained in S1 to the reaction vessel, heat and reflux the mixture while stirring, mix thoroughly, and then perform vacuum distillation to remove the diluent, thereby obtaining organosilicon-modified epoxy resin. S3. Cool the urushiol-modified epoxy resin containing organosilicon obtained in step 2 to room temperature, add a curing agent, stir evenly, coat it on the surface of the substrate, and cure it into a film to obtain the mussel-like anti-corrosion and anti-fouling integrated resin.

2. The preparation method of the mussel-like anti-corrosion and anti-fouling integrated resin according to claim 1, characterized in that: The amount of urushiol used is 0.1%-15% of the total resin mass, the amount of hydrogen-terminated polydimethylsiloxane used is 0.01%-3% of the total resin mass, and the sum of the amounts of epoxy resin and curing agent used is 82%-99.89% of the total resin mass. The amounts of curing agent and epoxy resin used are chemically equivalent.

3. The preparation method of the mussel-inspired anti-corrosion and anti-fouling integrated resin according to claim 1, characterized in that: The catalyst is one or more of platinum, cobalt, palladium, nickel, and rhodium.

4. The preparation method of the mussel-inspired anti-corrosion and anti-fouling integrated resin according to claim 1, characterized in that: The epoxy resin is one or more of glycidyl ether epoxy resin, glycidyl ester epoxy resin, and non-glycidyl epoxy resin.

5. The preparation method of the mussel-like anti-corrosion and anti-fouling integrated resin according to claim 1, characterized in that: The diluent is one or more of tetrahydrofuran, toluene, xylene, isopropanol, cyclohexanone, and ethylene glycol dimethyl ether.

6. The preparation method of the mussel-inspired anti-corrosion and anti-fouling integrated resin according to claim 1, characterized in that: The curing agent is one or more of amine curing agents, acid anhydride curing agents, and synthetic resin curing agents.

7. The preparation method of the mussel-like anti-corrosion and anti-fouling integrated resin according to claim 1, characterized in that: The amount of catalyst used is 1%-2% of the total mass of urushiol and hydrogen-terminated polydimethylsiloxane.

8. The method for preparing the mussel-like anti-corrosion and anti-fouling integrated resin according to claim 1, characterized in that: The reaction temperature in step S1 is 90-100℃ and the reaction time is 2-3 h; the reaction temperature in step S2 is 60-90℃.

9. The preparation method of the mussel-inspired anti-corrosion and anti-fouling integrated resin according to claim 1, characterized in that: In step S3, the substrate is carbon steel or aluminum alloy.

10. A mussel-inspired anti-corrosion and anti-fouling integrated resin, characterized in that: The resin is prepared using the method described in any one of claims 1-9 for the integrated anti-corrosion and anti-fouling properties of mussel-like resin.

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