Preparation method of impact-resistant, anti-corrosion and anti-fouling integrated coating

Abstract

The present invention discloses a method for preparing an impact-resistant, anti-corrosion, and anti-fouling integrated coating. First, a precursor having an isocyanate structure in the side chain is prepared by free radical polymerization of an isocyanate containing an unsaturated double bond, a fluorinated acrylate monomer, and KH570-modified graphene. Then, the precursor is subjected to addition polymerization with a polyhydroxy monomer having an antibacterial effect to prepare an impact-resistant, anti-corrosion, and anti-fouling integrated coating. Compared with conventional single-function coatings, the bactericidal polyhydroxy monomer grafted on the resin side chain can not only kill bacteria and hinder the formation of primary biofilms, but its polyhydroxy structure can chelate with metal ions and form a dense protective film with the metal matrix to prevent corrosion of the substrate. The polyurethane multi-network structure formed by the reaction of isocyanate and polyhydroxy monomer can absorb the impact of external forces and, together with graphene, improve the impact resistance of the coating.

Description

Technical Field

[0001] The invention relates to a method for preparing an impact-resistant, anti-corrosion and anti-fouling integrated coating. Background Art

[0002] Due to the special and complex environment of the ocean, metal materials under the water surface, such as ships, oil pipelines, and marine weather buoys, will not only suffer corrosion, reducing material strength or even causing serious damage, but will also be attached by marine fouling organisms, causing serious economic and ecological impacts.

[0003] The patent document with publication number CN116218372A discloses an anti-corrosion and anti-fouling coating. It uses fluorinated polysilazane resin and methoxy polysiloxane resin as film-forming substances, and compounded micro-nano fillers, additives, pigments and organic solvents to prepare a fluorinated polysilazane anti-corrosion and anti-fouling coating slurry. The prepared coating has a neutral salt spray resistance test of more than 1000 hours, an adhesion of level 0, and an impact strength of 70kg·cm-2. However, the anti-fouling effect of the coating relies solely on the desorption effect of the low surface energy of the film-forming substances fluorinated polysilazane resin and methoxy polysiloxane resin. No anti-fouling active substances are added, and the anti-fouling effect against the attachment of fouling organisms in a static marine environment is poor. Xia Xianchao of Huazhong University of Science and Technology used polydimethylsiloxane as a film-forming substance, and polyacrylic acid-modified zinc oxide and chitosan-coated betaine monohydrate microspheres as fillers, respectively. Two types of anti-corrosion and anti-fouling coatings were obtained by spraying. The corrosion current densities of the two coatings were 4.63×10 -12 A.cm -2 and 3.86×10 -12 A.cm -2 The antibacterial rates of the two were 81.1% and 85%, respectively, indicating that the prepared anticorrosion and antifouling coating has strong corrosion resistance and antibacterial properties. However, during the preparation process, the coating needs to be cured at 100°C for 2 hours, which greatly limits its practical application possibilities. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing an impact-resistant, anti-corrosion, and anti-fouling integrated coating. To achieve the above-mentioned purpose, the method for preparing an impact-resistant, anti-corrosion, and anti-fouling integrated coating provided by the present invention comprises the following steps:

[0005] (1) adding graphene and silane coupling agent KH570 into acetone to perform surface treatment on the graphene, and performing solid-liquid separation after the surface treatment. The separated solid is washed and dried to obtain modified graphene;

[0006] (2) a mixed monomer formed by mixing an isocyanate containing an unsaturated double bond and a fluorinated acrylate monomer with modified graphene is subjected to a one-stage free radical polymerization reaction under the action of initiator A; after the one-stage free radical polymerization reaction is completed, initiator B is added to carry out a two-stage free radical polymerization reaction, and a precursor is obtained after the reaction is completed;

[0007] (3) Adding a bactericidal polyhydroxy monomer to the precursor to carry out an addition polymerization reaction, and after the reaction is completed, an impact-resistant, anti-corrosion and anti-fouling integrated coating is obtained.

[0008] In the step (1), the mass ratio of the graphene to the silane coupling agent 570 is 1:5-2:1; the surface treatment is performed at a temperature of 45-60°C for 2-5 hours; the cleaning is performed using toluene; and the drying is performed by vacuum drying at a temperature of 55-65°C.

[0009] The specific operation of step (2) is as follows: adding the modified graphene to a mixture of propylene glycol methyl ether and xylene, adding the initiator A to a mixed monomer composed of an isocyanate containing an unsaturated double bond and a fluorinated acrylate monomer; adding the mixed monomer dropwise to the mixed solution at a temperature of 75-100°C, under nitrogen protection and stirring, to carry out a first-stage free radical polymerization reaction, and the mixed monomer is added dropwise for 4-10 hours; after the addition of the mixed monomer is completed, a xylene solution of the initiator B is added dropwise, and the addition time is 15 minutes to 1.5 hours. After the addition is completed, the reaction is continued for 1.5-3 hours. After the reaction is completed, a precursor is obtained.

[0010] The specific operation of step (3) is as follows: adding a 50 wt% acetone solution of a bactericidal polyhydroxy monomer to the precursor at a temperature of 50-75° C. and under stirring to carry out an addition polymerization reaction, the adding time being 0.5-3 hours, and obtaining an impact-resistant, anti-corrosion and anti-fouling integrated coating after the addition is completed.

[0011] The initiator A is azobisisobutyronitrile; the initiator B is tert-butyl benzoyl peroxide.

[0012] The amount of the modified graphene is 0.05%-10% of the mass of the mixed monomer; in the mixed solution of propylene glycol methyl ether and xylene, the mass ratio of propylene glycol methyl ether to xylene is 2:1-5:1, and the amount of propylene glycol methyl ether is 12%-40% of the mass of the mixed monomer; the amount of initiator A is 0.1%-5% of the mass of the mixed monomer; the amount of the xylene solution of initiator B is 0.5%-6% of the mass of the mixed monomer, and the mass ratio of initiator B to xylene in the xylene solution of initiator B is 1:10-1:26; the mass ratio of the unsaturated double bond isocyanate and the fluorine-containing acrylate monomer in the mixed monomer is 1:1-1:12.

[0013] The molar ratio of the bactericidal polyhydroxy monomer to the isocyanate containing an unsaturated double bond is 1:10-8:1.

[0014] The isocyanate containing an unsaturated double bond is isopropenyl-α,α-dimethylbenzyl isocyanate.

[0015] The fluorine-containing acrylic ester monomer is any one of trifluoroethyl methacrylate, hexafluorobutyl methacrylate and dodecafluoroheptyl methacrylate, or a mixture of two or more of them in any proportion.

[0016] The bactericidal polyhydroxy monomer is one of phytic acid, tannic acid and triethanolamine or a mixture of two or more of them in any proportion.

[0017] The impact-resistant, anti-corrosion and anti-fouling integrated coating prepared by the method of the present invention is applied to the surface of the substrate to form a wet film layer with a thickness of 75 microns to 300 microns. After the wet film layer dries and condenses, an impact-resistant, anti-corrosion and anti-fouling integrated coating can be formed on the surface of the substrate.

[0018] The present invention uses unsaturated isocyanate, KH570 modified graphene, and fluorine-containing acrylic monomers as raw materials to react to obtain a precursor with an isocyanate group on the side chain, and then reacts a bactericidal polyhydroxy monomer with the precursor to obtain an impact-resistant, anti-corrosion, and anti-fouling integrated coating. The impact-resistant, anti-corrosion, and anti-fouling integrated coating is applied to the surface of the substrate to form an impact-resistant, self-repairing, anti-corrosion, and anti-fouling integrated coating on the surface of the substrate. Compared with traditional marine protective coatings, the coating formed by the coating prepared by the present invention introduces a bactericidal polyhydroxy monomer, which can chelate with the metal ions on the metal substrate to form a dense protective film and play an anti-corrosion role. The physical cutting and oxidative stress effects of graphene, in conjunction with the bactericidal effect of the polyhydroxy monomer, jointly achieve an environmentally friendly and pollution-free anti-fouling effect. By controlling the ratio of the isocyanate monomer and the bactericidal polyhydroxy monomer, the coating can achieve the adjustment of self-repairing properties and anti-corrosion and anti-fouling properties. When isocyanate is present in excess, the coating exhibits a certain degree of self-healing properties. However, when the bactericidal polyhydroxy monomer is present in excess, this self-healing property disappears, and the anti-corrosion and anti-fouling properties are enhanced. The polyurethane multi-network structure formed by the reaction of isocyanate and polyhydroxy monomer can absorb external impacts and, together with graphene, enhances the coating's impact resistance.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. The anti-corrosion and anti-fouling functions are integrated, eliminating the need to apply anti-corrosion primer, connecting paint, and anti-fouling paint, thus simplifying the equipment protection process;

[0021] 2. The antifouling performance relies on the physical cutting and oxidative stress of graphene and the bactericidal effect of polyhydroxy monomers. It does not release heavy metal ions and highly toxic substances and is eco-friendly.

[0022] 3. The self-repairing performance and anti-corrosion and anti-fouling performance can be adjusted by adjusting the amount of monomer added. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below through examples, which are not intended to limit the scope of the present invention. Example 1

[0024] The preparation steps of the method for preparing the impact-resistant, anti-corrosion and anti-fouling integrated coating are as follows:

[0025] 0.05 g of the purchased hydroxylated graphene was added to 100 mL of acetone, and 0.25 g of silane coupling agent KH570 was added to the acetone. The hydroxylated graphene was surface treated at a temperature of 45°C under magnetic stirring for 2 hours. After the treatment, solid-liquid separation was performed to obtain solid particles. The solid particles were washed three times with toluene, and then the washed solid particles were vacuum dried at 55°C to obtain modified graphene after drying.

[0026] 0.04 g of modified graphene was added to a mixture of 4.8 g of propylene glycol methyl ether and 2.4 g of xylene. 0.04 g of azobisisobutyronitrile was then added to a monomer mixture consisting of 5 g of isopropenyl-α,α-dimethylbenzyl isocyanate and 35 g of dodecafluoroheptyl methacrylate. The monomer mixture was added dropwise to the mixture at 75°C under a nitrogen atmosphere and magnetic stirring at 70 rpm for 4 hours. After the monomer mixture was added dropwise, 0.2 g of a xylene solution of tert-butyl benzoyl peroxide was added dropwise over 15 minutes. After the addition was complete, the reaction was continued at 75°C under a nitrogen atmosphere and magnetic stirring at 70 rpm for 1.5 hours to obtain a precursor containing isocyanate groups in its side chains. The mass ratio of tert-butyl benzoyl peroxide to xylene in the xylene solution was 1:12.

[0027] Under magnetic stirring at 65°C and 75 rpm, 264 g of a 50 wt% phytic acid solution in acetone was added dropwise to the precursor for 3 hours. After the addition was complete, an impact-resistant, anti-corrosion, and anti-fouling integrated coating was obtained. The molar ratio of vinyl isocyanate to phytic acid was 1:8.

[0028] The obtained coating slurry was spin-coated on a metal substrate at a speed of 600 rpm to a thickness of about 120 μm. The prepared sample was dried at 35° C. to a constant weight.

[0029] Example 2

[0030] The operating steps are the same as those in Example 1, except that: in Example 2, the mass ratio of graphene and silane coupling agent 570 is 2:1, the hydroxylated graphene is surface treated for 5 hours, the surface treatment temperature is 60°C, the vacuum drying temperature is 65°C, the molar ratio of vinyl isocyanate and phytic acid is 1:4, the temperature of free radical polymerization is 100°C, the mixed monomer addition time is 10 hours, the xylene solution of initiator B is added dropwise for 1.5 hours, the fluorine-containing acrylate monomer is trifluoroethyl methacrylate, the amount of modified graphene is 0.5% of the mass of the mixed monomer, the mass ratio of propylene glycol methyl ether and xylene is 5:1, the amount of propylene glycol methyl ether is 40% of the mass of the mixed monomer, the amount of initiator A is 5% of the mass of the mixed monomer, the mass ratio of initiator B and xylene in the xylene solution of initiator B is 1:26, and the mass ratio of unsaturated double bond isocyanate and fluorine-containing acrylate monomer is 1:1.

[0031] Example 3

[0032] The operating steps are the same as those in Example 1, except that: in Example 3, the mass ratio of graphene and silane coupling agent 570 is 1:3, the surface treatment of hydroxylated graphene is 2.5 hours, the surface treatment temperature is 50°C, and the vacuum drying temperature is 57°C. In this embodiment, the molar ratio of vinyl isocyanate and triethanolamine is 1:1, the temperature of free radical polymerization is 80°C, the mixed monomer addition time is 5.5 hours, the xylene solution of initiator B is added dropwise for 30 minutes, the fluorine-containing acrylate monomer is hexafluorobutyl methacrylate, the amount of modified graphene is 5% of the mass of the mixed monomer, the mass ratio of propylene glycol methyl ether and xylene is 3:1, the amount of propylene glycol methyl ether is 20% of the mass of the mixed monomer, the amount of initiator A is 2% of the mass of the mixed monomer, the mass ratio of initiator B and xylene in the xylene solution of initiator B is 1:15, and the mass ratio of unsaturated double bond isocyanate and fluorine-containing acrylate monomer is 1:12.

[0033] Example 4

[0034] The operation steps are the same as those in Example 1, except that: in Example 4, the mass ratio of graphene to silane coupling agent 570 is 1:2, the surface treatment of hydroxylated graphene is 4 hours, the surface treatment temperature is 55°C, the vacuum drying temperature is 60°C, the molar ratio of the mixture of vinyl isocyanate, phytic acid, and tannic acid is 5:1, the temperature of free radical polymerization is 88°C, the dropwise addition time of the mixed monomer is 6.5 hours, the dropwise addition time of the xylene solution of initiator B is 45 minutes, and the fluorinated acrylate is 0.1% fluorinated acrylate. The monomer is a mixture of hexafluorobutyl methacrylate and dodecafluoroheptyl methacrylate, the amount of modified graphene is 0.05% of the mass of the mixed monomer, the mass ratio of propylene glycol methyl ether and xylene is 4:1, the amount of propylene glycol methyl ether is 28% of the mass of the mixed monomer, the amount of initiator A is 3% of the mass of the mixed monomer, the mass ratio of initiator B and xylene in the xylene solution of initiator B is 1:18, and the mass ratio of unsaturated double bond isocyanate and fluorine-containing acrylate monomer is 1:3.

[0035] Example 5

[0036] The operating steps are the same as those in Example 1, except that: in Example 5, the mass ratio of graphene and silane coupling agent 570 is 1:1, the hydroxylated graphene is surface treated for 3 hours, the surface treatment temperature is 58°C, the vacuum drying temperature is 62°C, the molar ratio of the mixture of vinyl isocyanate, phytic acid, and triethanolamine is 10:1, the temperature of free radical polymerization is 95°C, the mixed monomer is added dropwise for 8 hours, the xylene solution of initiator B is added dropwise for 70 minutes, the fluorinated acrylate monomer is a mixture of trifluoroethyl methacrylate and dodecafluoroheptyl methacrylate, etc., the amount of modified graphene is 10% of the mass of the mixed monomer, the amount of propylene glycol methyl ether is 36% of the mass of the mixed monomer, the amount of the initiator A is 4% of the mass of the mixed monomer, the mass ratio of initiator B and xylene in the xylene solution of initiator B is 1:23, and the mass ratio of the unsaturated double bond isocyanate and the fluorinated acrylate monomer is 1:10.

[0037] The impact-resistant, anti-corrosion, and anti-fouling integrated coatings prepared in Examples 1 to 5 were spin-coated onto polished tinplate to a wet film thickness of 175 μm. The coatings were then dried and solidified at 35°C for 48 hours to form protective coatings, thereby producing test samples. An acrylic silane antifouling coating, an acrylic boron antifouling coating, an acrylic copper antifouling coating, an acrylic zinc silicon antifouling coating, and an acrylic zinc antifouling coating were spin-coated onto polished tinplate to a wet film thickness of 175 μm. The coatings were then dried and solidified at 35°C for 48 hours to form protective coatings, thereby producing comparative samples, designated as Comparative Sample 1, Comparative Sample 2, Comparative Sample 3, Comparative Sample 4, and Comparative Sample 5, respectively.

[0038] The impact resistance test was conducted in a walk-in constant temperature and humidity test chamber in accordance with GB / T 1732-1993; the neutral salt spray resistance test was conducted in accordance with GB / T 10125-1997.

[0039] Antimicrobial properties were tested using the following method: First, the coating sample to be tested was sterilized using a 20 W, 253.7 nm UV lamp for 30 minutes. The sample was then placed in a culture dish containing 10 mL of LB liquid medium and diluted E. coli cells, and the concentration was calculated using a serial dilution method. The LB liquid medium was then incubated at 37°C for the desired time. The coated sample was then removed from the liquid medium, and the E. coli cells were separated from the coating surface using 10 mL of LB liquid medium. The LB liquid medium containing the separated E. coli was collected and diluted to 0.1% of its original concentration. Then, 10 μL of the diluted liquid medium was evenly scraped onto solid LB medium and incubated at 37°C for 24 hours. The number of E. coli colonies grown on the solid medium was recorded as U1. The same procedure was repeated on the original sample, which was recorded as a blank sample, and the number of E. coli colonies was recorded as U2. The antimicrobial rate, A, of the sample was calculated using the following formula:

[0040] .

[0041] Self-healing time determination method: Use a scalpel to create a 2.0 cm scratch on the coating of the sample. The scratch depth should be sufficient to expose the tinplate substrate. Place the scratched sample in deionized water at 75°C. Observe the self-healing process using an optical microscope and record the time it takes for the coating to fully heal.

[0042] The test samples and control samples were tested according to the above test method. The test results are shown in Table 1.

[0043] .

[0044] It can be seen from the test results that none of the comparison samples 1 to 5 have excellent impact resistance, neutral salt spray test resistance, antibacterial properties and self-repairing properties at the same time. The impact-resistant, anti-corrosion and anti-fouling integrated coating prepared by the present invention has the above-mentioned excellent properties. The more bactericidal polyhydroxy monomer is added, the longer the salt spray resistance time (the better the anticorrosion performance) and the better the antibacterial property. With the increase of the modified graphene content, the antibacterial property shows a phenomenon of first strengthening and then weakening. The antibacterial property is best when the addition amount is 1%. The more vinyl isocyanate monomer is added, the shorter the self-repairing time. The molar ratio of vinyl isocyanate to bactericidal polyhydroxy monomer is 1:1-5:1, which has good impact resistance.

Claims

1. A method for preparing an impact-resistant, anti-corrosion, and anti-fouling integrated coating, characterized by: The method comprises the following steps: (1) adding graphene and silane coupling agent KH570 into acetone to perform surface treatment on the graphene, and performing solid-liquid separation after the surface treatment. The separated solid is washed and dried to obtain modified graphene; (2) a mixed monomer formed by mixing an isocyanate containing an unsaturated double bond and a fluorinated acrylate monomer with modified graphene is subjected to a one-stage free radical polymerization reaction under the action of initiator A; after the one-stage free radical polymerization reaction is completed, initiator B is added to carry out a two-stage free radical polymerization reaction, and a precursor is obtained after the reaction is completed; (3) adding a bactericidal polyhydroxy monomer to the precursor to carry out addition polymerization reaction, and obtaining an impact-resistant, anti-corrosion and anti-fouling integrated coating after the reaction is completed; The isocyanate containing an unsaturated double bond is isopropenyl-α,α-dimethylbenzyl isocyanate; The bactericidal polyhydroxy monomer is one of phytic acid, tannic acid and triethanolamine or a mixture of two or more of them in any proportion.

2. The method for preparing the impact-resistant, anti-corrosion and anti-fouling integrated coating according to claim 1, wherein: In the step (1), the mass ratio of the graphene to the silane coupling agent KH570 is 1:5-2:1; the surface treatment is performed at a temperature of 45-60°C for 2-5 hours; the cleaning is performed using toluene; and the drying is performed by vacuum drying at a temperature of 55-65°C.

3. The method for preparing the impact-resistant, anti-corrosion and anti-fouling integrated coating according to claim 1, wherein: The specific operation of step (2) is as follows: adding the modified graphene to a mixture of propylene glycol methyl ether and xylene, adding the initiator A to a mixed monomer composed of an isocyanate containing an unsaturated double bond and a fluorinated acrylate monomer; adding the mixed monomer dropwise to the mixed solution at a temperature of 75-100°C, under nitrogen protection and stirring, to carry out a first-stage free radical polymerization reaction, and the mixed monomer is added dropwise for 4-10 hours; after the addition of the mixed monomer is completed, a xylene solution of the initiator B is added dropwise, and the addition time is 15 minutes to 1.5 hours. After the addition is completed, the reaction is continued for 1.5-3 hours. After the reaction is completed, a precursor is obtained.

4. The method for preparing the impact-resistant, anti-corrosion and anti-fouling integrated coating according to claim 1, wherein: The specific operation of step (3) is as follows: adding a 50 wt% acetone solution of a bactericidal polyhydroxy monomer to the precursor at a temperature of 50-75° C. and under stirring to carry out an addition polymerization reaction, the adding time being 0.5-3 hours, and obtaining an impact-resistant, anti-corrosion and anti-fouling integrated coating after the addition is completed.

5. The method for preparing the impact-resistant, anti-corrosion and anti-fouling integrated coating according to claim 1, wherein: The initiator A is azobisisobutyronitrile; the initiator B is tert-butyl benzoyl peroxide.

6. The method for preparing the impact-resistant, anti-corrosion and anti-fouling integrated coating according to claim 3, wherein: The amount of the modified graphene is 0.05%-10% of the mass of the mixed monomer; in the mixed solution of propylene glycol methyl ether and xylene, the mass ratio of propylene glycol methyl ether to xylene is 2:1-5:1, and the amount of propylene glycol methyl ether is 12%-40% of the mass of the mixed monomer; the amount of initiator A is 0.1%-5% of the mass of the mixed monomer; the amount of the xylene solution of initiator B is 0.5%-6% of the mass of the mixed monomer, and the mass ratio of initiator B to xylene in the xylene solution of initiator B is 1:10-1:26; the mass ratio of the unsaturated double bond isocyanate and the fluorine-containing acrylate monomer in the mixed monomer is 1:1-1:

12.

7. The method for preparing the impact-resistant, anti-corrosion and anti-fouling integrated coating according to claim 4, wherein: The molar ratio of the bactericidal polyhydroxy monomer to the isocyanate containing an unsaturated double bond is 1:10-8:

1.

8. The method for preparing the impact-resistant, anti-corrosion and anti-fouling integrated coating according to any one of claims 1 to 7, characterized in that: The fluorine-containing acrylic ester monomer is any one of trifluoroethyl methacrylate, hexafluorobutyl methacrylate and dodecafluoroheptyl methacrylate, or a mixture of two or more of them in any proportion.