Photocurable coating, coating layer and use thereof

Abstract

This invention discloses a photocurable coating, a coating layer, and their applications, belonging to the field of coating technology. A photocurable coating, by weight, comprises the following components: 25-100 parts of epoxy-modified silicone resin A; 25-100 parts of epoxy-modified silicone resin B; 1-10 parts of photoinitiator; and 1-10 parts of sulfide; wherein epoxy-modified silicone resin A is tetraepoxycyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane; epoxy-modified silicone resin B is diepoxycyclohexylethyl-1,1,3,3-tetramethyldisiloxane; and the sulfide contains polysulfide bonds. The photocurable coating of this invention, after photocuring, forms a coating with good mechanical properties, excellent corrosion resistance, and long-lasting antibacterial properties, effectively protecting the material surface, slowing down corrosion, reducing maintenance costs, and extending the material's service life.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and more specifically, to a photocurable coating, a coating layer and its application. Background Technology

[0002] With industrial development, metallic materials are widely used in various fields, such as construction, machinery, and marine transportation. However, metallic materials are susceptible to corrosion and contamination during use, leading to a decline in material performance or even failure. Therefore, to protect the surface of metallic materials, protective treatment is necessary, and applying anti-corrosion and anti-fouling coatings is currently the most effective protective measure.

[0003] Organosilicon materials possess Si-O-Si bonds, with organic groups linked to silicon atoms. This gives the polymer several advantages: flexibility, low surface energy, and excellent thermal stability. However, it also results in disadvantages such as poor adhesion and low strength. Compared to most commercially available fluorosilicone coatings, organosilicon coatings are more environmentally friendly, and their superior flexibility allows for a wider range of applications.

[0004] Epoxy resin has the advantages of good adhesion and excellent corrosion resistance. The highly cross-linked network formed during its curing process can prevent corrosive media from reaching the substrate interface. On the other hand, it makes it difficult for molecules to slip, which can easily cause cracks in the coating.

[0005] Therefore, by grafting epoxy groups onto organosilicon polymers, the resulting epoxy-modified organosilicon polymers can overcome the shortcomings of single materials, giving the materials both the advantages of corrosion resistance and good thermal stability.

[0006] Traditional thermosetting methods are limited by economic and environmental constraints, leading to strong support and rapid development of ultraviolet (UV) curing technology. UV curing stands out due to its high efficiency and low energy consumption. Compared to free radical curing, cationic UV curing offers unique advantages such as oxygen-free inhibition and low shrinkage. It allows photopolymerization to occur in an inert gas-free environment and facilitates adhesion to the substrate. Furthermore, even after the light source is removed, cationic UV curing can maintain the reaction process until the resin is fully cured. Therefore, cationic UV curing, with its unique advantages, has considerable application potential in fields such as coating curing.

[0007] With the exploitation of marine resources, the time and frequency of offshore operations have increased. Marine microorganisms and pathogens often inhabit and multiply on the surfaces of working machinery, posing a potential threat to the health of workers. Current coatings developed for marine engineering often focus on improving their corrosion resistance and biofouling prevention capabilities, neglecting the inhibition and inactivation of marine microorganisms. Some antibacterial coatings incorporate small-molecule antibacterial agents to kill microorganisms, but these coatings have a short lifespan; the antibacterial agents migrate to the coating surface quickly, rapidly depleting and becoming ineffective.

[0008] Existing technology discloses a photocurable phenyl fluorosilicone modified epoxy resin coating, comprising a resin composed of a photocurable phenyl fluorosilicone modified epoxy resin and a 2-4 functional epoxy oligomeric siloxane reactive diluent, as well as a cationic photoinitiator. The coating obtained after UV curing exhibits anti-corrosion and anti-fouling properties. However, this coating does not solve the technical problem of poor antibacterial properties. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the defect of poor antibacterial properties of existing anti-corrosion and anti-fouling coatings, and to provide a light-curing coating that forms a light-curing coating with good mechanical properties, excellent corrosion resistance and long-lasting antibacterial properties, which can effectively protect the metal surface and extend the service life of the metal.

[0010] Another object of the present invention is to provide a coating.

[0011] Another object of the present invention is to provide an application of the coating in marine engineering and industrial corrosion and fouling prevention.

[0012] The above-mentioned objective of this invention is achieved through the following technical solution:

[0013] A UV-curable coating, comprising the following components by weight:

[0014]

[0015] Among them, epoxy-modified silicone resin A is tetraepoxycyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane;

[0016] The epoxy-modified silicone resin B is a diepoxycyclohexylethyl-1,1,3,3-tetramethyldisiloxane.

[0017] The sulfide contains polysulfide bonds.

[0018] The photocurable coating of this invention includes two epoxy-modified silicone resin materials, which improves upon the defects of single resins curing into coatings that are prone to cracking or wrinkling. The high-density cross-linked network formed after curing of the epoxy-modified silicone resin effectively blocks contact between the substrate and corrosive media, enhancing the coating's corrosion resistance. Furthermore, the multi-microporous structure formed after curing of the epoxy-modified silicone resin allows the coating to have a large surface area and conductive paths, significantly increasing the surface impedance and improving the coating's corrosion resistance.

[0019] The polysulfide bonds in sulfides can bind to proteins in the cell membranes of microorganisms, disrupting the spatial structure of the proteins, thereby causing cell death or loss of activity, thus enabling the coating formed by the UV-cured paint to achieve antibacterial function.

[0020] Preferably, the sulfide is one or more of bis[γ-(triethoxysilyl)propyl]-tetrasulfide, bis-[3-(triethoxysilyl)propyl]-disulfide, or diallyl tetrasulfide.

[0021] More preferably, the sulfide contains a tetrasulfide bond; the sulfide is bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0022] The Si-OH bonds generated after the hydrolysis of bis[γ-(triethoxysilyl)propyl]-tetrasulfide can improve the adhesion between the coating and the substrate and extend the service life of the substrate.

[0023] This invention solves the problem of rapid migration rate of antibacterial agents by using a macromolecular sulfur-containing silane coupling agent, thus achieving long-lasting antibacterial function. At the same time, as a coupling agent, it enhances the adhesion of the coating to the substrate, improves the anti-corrosion performance of the coating, and extends the service life and protective effect of the coating.

[0024] Preferably, the photoinitiator is a cationic photoinitiator; the cationic photoinitiator is one or more of triarylsulfonium hexafluoroantimonate (cationic photoinitiator 010), diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate (cationic photoinitiator 6976), triarylsulfonium hexafluoroantimonate (cationic photoinitiator 831), or isopropylphenylcyclopentadiene iron hexafluorophosphate (cationic photoinitiator 261).

[0025] The photoinitiator is a cationic photoinitiator. Cationic photocuring does not exhibit oxygen inhibition and has low requirements for environmental conditions. This eliminates the need for an inert gas during coating polymerization, simplifying the operating conditions. Cationic photocuring also features a "dark reaction" characteristic; once polymerization begins, the coating continues to polymerize and cure even after the light source is removed.

[0026] Preferably, the weight ratio of epoxy-modified silicone resin A to epoxy-modified silicone resin B is:

[0027] (0.3~0.7):1.

[0028] The present invention also protects a coating prepared by photocuring the photocurable coating described in any of the preceding claims.

[0029] The photocurable coating of the present invention can form an anti-corrosion and anti-fouling coating through photocuring, making the coating construction process simple and quick, reducing the construction difficulty and cost during coating, and greatly saving construction time.

[0030] The coating of this invention can be cured at room temperature by light curing, thereby reducing production costs and environmental pollution.

[0031] Preferably, the coating has a solid content of 100%.

[0032] Preferably, the photocuring conversion rate of the coating is 40-75%.

[0033] Preferably, the coating has a critical exposure level below 85 mJ / cm. 2 Cured under ultraviolet light.

[0034] The present invention also protects the application of the coating described in any of the above claims in improving the corrosion resistance and antibacterial properties of metallic materials.

[0035] This invention also protects the application of the coating described in any of the above claims in marine engineering and industrial corrosion and fouling prevention.

[0036] The coating prepared by the present invention is a novel surface protection material with broad application prospects, which can bring more value and competitiveness to the industrial and technological fields.

[0037] Preferably, the coating is applied to a metal substrate and cured by ultraviolet light to obtain a metal material with an anti-corrosion and anti-fouling coating.

[0038] The metal substrate can be iron.

[0039] The metal material substrate can be tinplate.

[0040] The coating method can be scraping.

[0041] Compared with the prior art, the beneficial effects of the present invention are:

[0042] The photocurable coating of this invention forms a coating with good mechanical properties, excellent corrosion resistance and antibacterial properties after photocuring. It can effectively protect the material surface, slow down the corrosion of the material, reduce the material maintenance cost and extend the service life of the material.

[0043] The coating formed by the photocurable coating of this invention has a salt water resistance of at least 336 hours. In EIS electrochemical testing, the coating impedance value still reaches 10 after 21 days of salt water immersion. 9 ohm·cm 2 Furthermore, it also has a good ability to inhibit diatom cells, with an antibacterial rate of over 45% after 30 days. Attached Figure Description

[0044] Figure 1 The image shows the surface corrosion of the anti-corrosion and anti-fouling coatings prepared by the methods of Comparative Example 3, Example 7, and Example 8 after immersion in a 3.5 wt.% sodium chloride solution for 21 days.

[0045] Figure 2 The images show SEM images of diatom cells on the coating surface during the anti-diatom performance test of the anti-corrosion and anti-fouling coatings prepared by the methods of Comparative Examples 3, 7, and 8.

[0046] Figure 3 Images showing the surface conditions of Comparative Example 1 and Comparative Example 2. Detailed Implementation

[0047] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0048] Tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, CAS number 121225-98-7.

[0049] Diepoxycyclohexylethyl-1,1,3,3-tetramethyldisiloxane, CAS number 18724-32-8.

[0050] Photoinitiator: Triarylsulfonium hexafluoroantimonate, CAS No. 109037-75-4.

[0051] Sulfide 1: bis[γ-(triethoxysilyl)propyl]-tetrasulfide, CAS number 40372-72-3.

[0052] Sulfide 2: bis[3-(triethoxysilyl)propyl]-disulfide, CAS No. 56706-10-6.

[0053] Sulfide 3: diallyl tetrasulfide, CAS number 2179-57-9.

[0054] Example 1

[0055] A UV-curable coating is made from the following components in parts by weight:

[0056] 50 parts of tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 50 parts of dicyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 2 parts of triarylsulfonium hexafluoroantimonate, and 5 parts of bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0057] The preparation method of the coating is as follows:

[0058] (1) Under light-protected conditions, 2g of triarylsulfonium hexafluoroantimonate was fully dissolved in acetone, and then mixed evenly with 50g of tetracyclic cyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 50g of dicyclic cyclohexylethyl-1,1,3,3-tetramethyldisiloxane and 5g of bis[γ-(triethoxysilyl)propyl]-tetrasulfide. The mixture was sheared and dispersed in a magnetic stirrer for 30min, and finally placed in an ultrasonic instrument for defoaming for 30min to obtain the coating.

[0059] (2) The coating prepared in the above embodiment is applied to the surface of the tinplate after grinding and cleaning, and the coating is evenly applied using a coating tool. The coating is placed under ultraviolet light for 30 seconds to cure the coating into a film, thus obtaining the coating layer.

[0060] Example 2

[0061] A UV-curable coating is made from the following components in parts by weight:

[0062] 66 parts of tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 33 parts of dicyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 2 parts of triarylsulfonium hexafluoroantimonate, and 5 parts of bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0063] The preparation method of the coating is as follows:

[0064] (1) Under light-protected conditions, 2g of triarylsulfonium hexafluoroantimonate was fully dissolved in acetone, and then mixed evenly with 66g of tetracyclic cyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 33g of dicyclic cyclohexylethyl-1,1,3,3-tetramethyldisiloxane and 5g of bis[γ-(triethoxysilyl)propyl]-tetrasulfide. The mixture was sheared and dispersed in a magnetic stirrer for 30min, and finally placed in an ultrasonic instrument for defoaming for 30min to obtain the coating.

[0065] (2) The preparation method of the coating is the same as that in Example 1.

[0066] Example 3

[0067] A UV-curable coating is made from the following components in parts by weight:

[0068] 25 parts of tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 75 parts of dicyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 2 parts of triarylsulfonium hexafluoroantimonate, and 5 parts of bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0069] The preparation method of the coating is as follows:

[0070] (1) Under light-protected conditions, 2g of triarylsulfonium hexafluoroantimonate was fully dissolved in acetone, and then mixed evenly with 25g of tetracyclic cyclohexyl ethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 75g of dicyclic cyclohexyl ethyl-1,1,3,3-tetramethyldisiloxane and 5g of bis[γ-(triethoxysilyl)propyl]-tetrasulfide. The mixture was sheared and dispersed in a magnetic stirrer for 30 min, and finally placed in an ultrasonic instrument for defoaming for 30 min to obtain the coating.

[0071] (2) The preparation method of the coating is the same as that in Example 1.

[0072] Example 4

[0073] A UV-curable coating is made from the following components in parts by weight:

[0074] 75 parts of tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 25 parts of dicyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 2 parts of triarylsulfonium hexafluoroantimonate, and 5 parts of bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0075] The preparation method is the same as in Example 1.

[0076] Example 5

[0077] A UV-curable coating is made from the following components in parts by weight:

[0078] 33 parts of tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 66 parts of dicyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 1 part of triarylsulfonium hexafluoroantimonate, and 5 parts of bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0079] The preparation method is the same as in Example 1.

[0080] Example 6

[0081] A UV-curable coating is made from the following components in parts by weight:

[0082] 33 parts of tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 66 parts of dicyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 10 parts of triarylsulfonium hexafluoroantimonate, and 5 parts of bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0083] The preparation method is the same as in Example 1.

[0084] Example 7

[0085] A UV-curable coating is made from the following components in parts by weight:

[0086] 33 parts of tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 66 parts of dicyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 2 parts of triarylsulfonium hexafluoroantimonate, and 2.5 parts of bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0087] The preparation method is the same as in Example 1.

[0088] Example 8

[0089] A UV-curable coating is made from the following components in parts by weight:

[0090] 33 parts of tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 66 parts of dicyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 2 parts of triarylsulfonium hexafluoroantimonate, and 5 parts of bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0091] The preparation method is the same as in Example 1.

[0092] Example 9

[0093] A UV-curable coating is made from the following components in parts by weight:

[0094] 33 parts of tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 66 parts of dicyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 2 parts of triarylsulfonium hexafluoroantimonate, and 10 parts of bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0095] The preparation method is the same as in Example 1.

[0096] Example 10

[0097] A UV-curable coating is made from the following components in parts by weight:

[0098] 33 parts of tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 66 parts of dicyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 2 parts of triarylsulfonium hexafluoroantimonate, and 5 parts of bis-[3-(triethoxysilyl)propyl]-disulfide.

[0099] The preparation method is the same as in Example 1.

[0100] Example 11

[0101] A UV-curable coating is made from the following components in parts by weight:

[0102] 33 parts of tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 66 parts of dicyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 2 parts of triarylsulfonium hexafluoroantimonate, and 5 parts of diallyl tetrasulfide.

[0103] The preparation method is the same as in Example 1.

[0104] Comparative Example 1

[0105] A UV-curable coating is made from the following components in parts by weight:

[0106] 99 parts of tetracyclic cyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 2 parts of triarylsulfonium hexafluoroantimonate, and 5 parts of bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0107] The only difference from Example 8 is that it does not include diepoxycyclohexylethyl-1,1,3,3-tetramethyldisiloxane.

[0108] The preparation method is the same as in Example 1.

[0109] Comparative Example 2

[0110] A UV-curable coating is made from the following components in parts by weight:

[0111] 99 parts of diepoxycyclohexylethyl-1,1,3,3-tetramethyldisiloxane, 2 parts of triarylsulfonium hexafluoroantimonate, and 5 parts of bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0112] The only difference from Example 8 is that it does not include tetracyclic cyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane.

[0113] The preparation method is the same as in Example 1.

[0114] Comparative Example 3

[0115] A UV-curable coating is made from the following components in parts by weight:

[0116] 33 parts of tetracyclic cyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, 66 parts of dicyclic cyclohexylethyl-1,1,3,3-tetramethyldisiloxane, and 2 parts of triarylsulfonium hexafluoroantimonate.

[0117] The only difference from Example 8 is that it does not include bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

[0118] The preparation method is the same as in Example 1.

[0119] Result detection

[0120] The performance testing of the coating in this invention was conducted according to the following test methods or standards, and the test results are shown in Table 1:

[0121] (1) Tensile test

[0122] Tensile tests were performed using a general-purpose testing machine (CMT6000, SANS). The dumbbell-shaped specimens conformed to ASTM D882-2018 standard, and the crosshead speed was 50 mm / min. -1 .

[0123] (2) Pencil hardness test

[0124] The pencil hardness of the cured coating was determined using a BY-500G pencil hardness tester (Shanghai, China) in accordance with the requirements of GB / T6739-2006.

[0125] (3) Static water contact angle test

[0126] The contact angle was measured using a JY-PHB type contact angle measuring instrument (Chengde Jinhe Instrument Manufacturing Co., Ltd.).

[0127] (4) Salt water resistance test (3.5% NaCl)

[0128] The salt solution immersion test was conducted as follows: First, both sides of the tinplate were uniformly ground and cleaned with acetone solution. After the coating cured, it was vertically placed in a 3.5 wt.% sodium chloride solution. The equipment was placed in a well-ventilated area, and the brine was changed daily until visible pitting corrosion appeared on the surface of the coated tinplate, at which point the test was completed. The test results are as follows: Figure 1 As shown.

[0129] (5) Electrochemical impedance spectroscopy

[0130] The corrosion behavior of four coatings was investigated using electrochemical impedance spectroscopy at open circuit potential using a CHI660E electrochemical workstation (Shanghai, China). The thickness of the dry coating was determined to be 200 ± 5 μm using a CH-1-S thickness gauge (Shanghai Liuling Instrument Factory, China). The experiments were conducted in a 3.5 wt.% sodium chloride solution at a frequency of 10 Hz. -2 ~10 5 The Hz frequency was monitored, with a perturbation voltage of ±20mV. Tests were conducted in a three-electrode cell, where the coated sample served as the working electrode, with an exposed area of ​​3.14 cm². 2 All electrochemical measurements were performed using a three-electrode system, comprising a saturated Ag / AgCl electrode as the reference electrode, graphite as the counter electrode, and Q235 steel as the working electrode. Electrochemical data were fitted using ZSimpWin software, and EIS data were fitted using the Q(R(QR)) model.

[0131] (6) Antifouling performance

[0132] A diatom culture medium of a certain concentration was cultured on top of the coating. After several days, the culture was removed and dropped onto a hemocytometer, and the cells were counted using an optical microscope. The microscopic morphology of the residual diatom cells on the coating surface was observed using a scanning electron microscope (Hitachi S-4800). The test results are as follows: Figure 2 As shown. According to Figure 2 The diatom cell inhibition rate was calculated, and the antifouling performance was expressed as the diatom cell inhibition rate.

[0133] (7) Photopolymerization conversion rate: Real-time infrared spectroscopy (RT-IR) was performed on a Nicoleti S50 spectrometer (Thermo Scientific) using a KBr plate to support the material. In-situ UV irradiation of the silicone-epoxy prepolymer was conducted using a 365nm UV-LED light source (LAMPLIC, Shenzhen). The photopolymerization conversion rate (Cg) of the silicone-epoxy resin in the resin was calculated. t C t It is based on the real-time infrared spectrum 883cm -1 The value is calculated from the change in the area of ​​the absorption peak of the epoxy group. In the formula, A0 and A t The peak areas of the organosilicon-epoxy resin at different times before and after ultraviolet light irradiation (883 cm⁻¹) are respectively. -1 ).

[0134] (8) Coating Surface Condition: After applying the coating to the iron sheet surface, allow it to stand until it levels, then expose the coating to a UV light source for 30 seconds. Afterward, remove the sheet and visually inspect the coating surface for any obvious defects. Surface condition images of Comparative Example 1 and Comparative Example 2 are shown below. Figure 3 As shown.

[0135] (9) Coating solids content: Drop A grams (approximately 1 gram) of coating without photoinitiator into a concave bowl-shaped piece of tin foil (weigh the tin foil as B grams), place it in an oven at 100–120°C, and after 5 hours, remove the tin foil and weigh the total weight as C grams (the weight of the tin foil plus the remaining coating). According to the formula... Calculate the solid content of the coating.

[0136] (10) Coating adhesion: Refer to GBT9286-1998 "Cross-cut test of paints and varnishes" standard, grade 0 is the best.

[0137] (11) Photopolymerization Exposure: The 365nm LED UV light source irradiation probe was fixed at a certain height with an iron frame. The light intensity and exposure energy after the light source was turned on were measured and recorded using a UV irradiation instrument. By adjusting the height of the light source irradiation probe and the voltage of the light source irradiation machine, the light intensity of the irradiated area was fixed at 20mW / cm². 2 The irradiation time of the ultraviolet point light source was adjusted (2, 6, 10, 14, 18, 22 s), and the energy E0 (mJ / cm²) at different irradiation times was recorded using an ultraviolet irradiation instrument. 2 After the predetermined irradiation time is reached, the average thickness of the cured sample is measured and recorded using a thickness gauge. The average thickness is the curing depth C. d (mm), to obtain a series of exposure energies E0 and their corresponding curing depths C d And perform linear fitting on it to obtain the corresponding fitting curve. According to the empirical formula C d =D p ×ln(E0-E c The corresponding critical exposure value E was calculated. c (mJ / cm 2 ) and transmission depth D p (mm). (Critical Exposure E) c The smaller the better)

[0138] The specific detection results for each embodiment are shown in Table 1 below:

[0139] Table 1 Comparison of performance test results of the photocurable coatings prepared in each embodiment

[0140]

[0141] Continued from Table 1

[0142]

[0143] The specific test results for each comparative example are shown in Table 2 below:

[0144] Table 2 Comparison of performance test results of the photocurable coatings prepared in each comparative example

[0145]

[0146]

[0147] As can be seen from the above data, the cationic photocurable anti-corrosion and anti-fouling coating prepared by the embodiment of the present invention has a smooth and flat surface, and good tensile strength, elongation at break, and hardness. The tensile strength can reach 3.0-14.5 MPa, the elongation at break can reach 2.2-8.0%, the hardness can reach B-4H, and the adhesion grade can reach 0-1. The high-density cross-linked network formed by the coating effectively blocks the penetration of corrosive media. The addition of sulfides enhances the adhesion of the coating, so that after 14 days of salt water immersion, the coating surface shows no obvious corrosion, and the impedance value remains at 10. 9 ohm·cm 2 The contact angle is 84.1–87.5°. The sulfide contains polysulfide bonds, which also act as an antifouling agent, capable of damaging proteins in cells. After 30 days of testing, the coating showed an inhibition rate of 46.9–89.3% against diatom cells. After 180 days of testing, the coatings in some embodiments still showed an inhibition rate as high as 75% against diatom cells, demonstrating good and long-lasting antifouling performance. Furthermore, the coatings obtained after photocuring in the embodiments of the present invention have 100% solids content, require no solvent evaporation before curing, and have a photocuring conversion rate of 43.7–70.5% and a concentration of less than 85 mJ / cm³. 2 The critical exposure level.

[0148] As can be seen from the examples and Comparative Examples 1 and 2, when a single resin is used to cure a coating, it is prone to cracking or wrinkling and cannot form a smooth and flat coating.

[0149] As can be seen from Examples 1-4 and Example 8, the weight ratio of epoxy-modified silicone resin A to epoxy-modified silicone resin B is (0.3-0.7):1, which has a higher impedance value and a lower critical exposure, and requires less energy for curing.

[0150] As can be seen from Examples 5, 6, and 8, the amount of photoinitiator directly affects the photocuring conversion rate of the coating. With insufficient photoinitiator, the system cannot generate enough initiating factors (protic acids) to initiate the ring-opening polymerization of epoxy groups, resulting in insufficient curing of the coating and thus increasing the photocuring conversion rate and critical exposure. Conversely, with excessive photoinitiator, the improvement in photocuring conversion rate is limited, increasing costs unnecessarily and resulting in waste.

[0151] As can be seen from Examples 7-9, a larger amount of sulfide is more beneficial to improving the adhesion of the coating. However, the amount of sulfide should not be too large, lest it affect the photocuring process of the coating, reduce the crosslinking density of the coating, and thus lead to a decrease in the mechanical properties and anti-corrosion properties of the coating. As shown in Example 8, adding an appropriate amount of sulfide allows the coating to maintain good mechanical properties and adhesion level, while also having excellent anti-corrosion and antibacterial properties.

[0152] As can be seen from Examples 8, 10, 11 and Comparative Example 3, sulfides in the coating are beneficial to improving the antibacterial effect of the coating. Furthermore, when the sulfide is bis[γ-(triethoxysilyl)propyl]-tetrasulfide or bis-[3-(triethoxysilyl)propyl]-disulfide, it is even more beneficial to improve the long-term antibacterial performance of the coating.

[0153] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A photocurable coating for application onto the surface of metal materials, characterized in that, By weight, it includes the following components: Epoxy-modified silicone resin A, 25-100 parts; Epoxy-modified silicone resin B25~100 parts; 1-10 parts of photoinitiator; Sulfide 1-10 parts; Among them, epoxy-modified silicone resin A is tetraepoxycyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane; The epoxy-modified silicone resin B is a diepoxycyclohexylethyl-1,1,3,3-tetramethyldisiloxane. The sulfide is one or more of bis[γ-(triethoxysilyl)propyl]-tetrasulfide, bis-[3-(triethoxysilyl)propyl]-disulfide or diallyl tetrasulfide; The weight ratio of epoxy-modified silicone resin A to diepoxy-modified silicone resin B is (0.3~0.7):

1.

2. The photocurable coating for coating on the surface of metal materials as described in claim 1, characterized in that, The sulfide is bis[γ-(triethoxysilyl)propyl]-tetrasulfide.

3. The photocurable coating for coating on the surface of metal materials as described in claim 1, characterized in that, The photoinitiator is a cationic photoinitiator.

4. The photocurable coating for coating on the surface of metal materials as described in claim 3, characterized in that, The cationic photoinitiator is one or more of triarylsulfonium hexafluoroantimonate, diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate, triarylsulfonium hexafluoroantimonate, or isopropylphenylcyclopentadiene iron hexafluorophosphate.

5. The coating obtained by curing the photocurable coating for coating on the surface of a metal material as described in any one of claims 1 to 4 by ultraviolet light.

6. The coating as described in claim 5, characterized in that, The coating has a solid content of 100%.

7. The coating as described in claim 5, characterized in that, The photocuring conversion rate of the coating is 40-75%.

8. The coating as described in claim 5, characterized in that, The coating is applied at a critical exposure level below 85 mJ / cm. 2 Cured under ultraviolet light.

9. The application of the coating according to any one of claims 5 to 8 in improving the corrosion resistance and antibacterial properties of metallic materials.

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