A method for preparing a soluble polyimide / acrylic ion crosslinking type antifouling coating

Abstract

The application provides a preparation method of a soluble polyimide / acrylic acid ion crosslinking type antifouling coating and relates to the technical field of antifouling materials. The soluble polyimide / acrylic acid ion crosslinking type antifouling coating is prepared by blending carboxyl-containing non-fully imidized polyimide and polyacrylic acid salt containing metal ions, wherein the carboxyl-containing non-fully imidized polyimide has good solubility in a low-boiling-point solvent, good film-forming property, and the prepared antifouling coating has excellent antifouling performance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of antifouling materials, in particular to a preparation method of a soluble polyimide / acrylic ion crosslinking type antifouling coating. BACKGROUND

[0002] Polyimide (PI) is a kind of polymer material with excellent comprehensive performance. The main chain of PI contains both aromatic rings and imide groups, which leads to the formation of a conjugated system such as pi-pi and p-pi between the molecular chains, which is beneficial to the polarization and charge transfer of electrons in the system. Therefore, the PI main chain structure is relatively rigid, and there is also a strong interaction between the molecular chains, which makes it difficult to directly form a film through polymer solution casting or melt casting, increasing the processing difficulty. The specific molecular structure of PI endows it with unique and excellent properties, such as strong solvent resistance, high melting temperature, excellent mechanical and electro-optical properties, and therefore, it has a wide application in the preparation of protective coatings, microelectronic materials and vehicle engineering. It is necessary and challenging to reduce the rigidity of the molecular chain of PI while maintaining its inherent heat resistance and other excellent properties, and to increase its solubility in organic solvents.

[0003] With the increasing emphasis on environmental protection, organic tin self-polishing antifouling paint is gradually replaced by various tin-free self-polishing antifouling paints, among which the antifouling paint based on polyacrylic zinc resin has developed rapidly. The antifouling paint not only effectively prevents marine biofouling, but also prolongs the docking period of the ship and maintains the smooth surface state, and gradually obtains the application proof of various self-polishing antifouling systems. SUMMARY

[0004] The application aims to provide a preparation method of a soluble polyimide / acrylic ion crosslinking type antifouling coating. The application uses carboxyl-containing non-fully imidized polyimide and metal ion-containing polyacrylate to prepare a soluble polyimide / acrylic ion crosslinking type antifouling coating. The carboxyl-containing non-fully imidized polyimide has good solubility in a low-boiling-point solvent and good film-forming property, and the prepared antifouling coating has excellent antifouling performance.

[0005] In order to achieve the above-mentioned application purposes, the application provides the following technical scheme:

[0006] The application provides a preparation method of a soluble polyimide / acrylic ion crosslinking type antifouling coating, which comprises the following steps:

[0007] The dianhydride monomer, the diamine monomer and the aprotic high-boiling-point solvent are mixed to perform a polycondensation reaction, so that polyamide acid is obtained;

[0008] The polyamic acid is placed in a mixed solution of acetic anhydride, triethylamine and acetone to perform incomplete imidization to obtain a carboxyl-containing incompletely imidized polyimide;

[0009] The carboxyl-containing incompletely imidized polyimide, metal ion-containing polyacrylate and low-boiling-point solvent are mixed to obtain a film-forming solution; the metal ion-containing polyacrylate includes one or more of zinc polyacrylate and copper polyacrylate;

[0010] The film-forming solution is subjected to film formation to obtain a soluble polyimide / acrylic acid ion crosslinking type antifouling coating.

[0011] Preferably, the dianhydride monomer includes one or more of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, pyromellitic dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride and 3,3',4,4'-benzophenonetetracarboxylic dianhydride;

[0012] The diamine monomer includes one or more of 4,4'-oxydianiline, 3,4-oxydianiline, 3,3'-oxydianiline, 4,4'-diaminodiphenyl sulfide, 3,4-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,4-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobiphenyl, 3,4-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4-diaminobenzophenone, 3,3'-diaminobenzophenone and 2,2-bis(4-aminophenyl)hexafluoropropane.

[0013] Preferably, the molecular weight of the polyamic acid is controlled according to formula I:

[0014] M ÷ repeating unit molecular weight = Xn = (1 + r) / (1 - r), formula I;

[0015] In formula I, M represents the molecular weight of the polyamic acid; Xn represents the degree of polymerization; r represents the molar ratio of anhydride monomer to amine monomer.

[0016] Preferably, the polycondensation reaction is performed under room temperature conditions; the time of the polycondensation reaction is 20-30 h.

[0017] Preferably, the volume ratio of acetic anhydride, triethylamine and acetone in the mixed solution of acetic anhydride, triethylamine and acetone is 1-3:1:10.

[0018] Preferably, the incomplete imidization is performed under room temperature conditions; the time of the incomplete imidization is 0.5-3 h.

[0019] Preferably, the molar ratio of the carboxyl-containing incompletely imidized polyimide and the polyacrylate containing metal ions is 0.175-0.7:1.

[0020] Preferably, the low-boiling solvent comprises tetrahydrofuran, dichloromethane or chloroform.

[0021] Preferably, the solid content of the film-forming solution is 10-20 wt%.

[0022] Preferably, the film-forming is carried out at room temperature; the film-forming time is 3-5 h.

[0023] The present application provides a preparation method of a soluble polyimide / acrylic ion crosslinking type antifouling coating. The carboxyl-containing incompletely imidized polyimide prepared by the present application has good solubility in common low-boiling solvents such as dichloromethane, chloroform and tetrahydrofuran. This is because the imidization degree of the polyimide is controllable, and the polymer chain regularity is not high, thereby effectively improving the solubility of the polyimide. The carboxyl-containing incompletely imidized polyimide prepared by the present application has good film-forming property. Since a low-boiling solvent is used as a solvent, the film-forming solution can be naturally dried to form a film at room temperature and the time is relatively short (3-5 h). The soluble polyimide / acrylic ion crosslinking type antifouling coating prepared by the present application has a smooth surface and uniform texture.

[0024] The present application utilizes the coordination crosslinking of zinc ions and / or copper ions in the polyacrylate and carboxyl groups in the polyimide molecular chain to form a soluble polyimide / acrylic ion crosslinking type antifouling coating, which has good antifouling performance. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The process flow chart for preparing the soluble polyimide / acrylic ion crosslinking type antifouling coating in the embodiments of the present application is shown in Figure 1.

[0026] Figure 2 The synthesis route of the polyamic acid in the embodiments is shown in Figure 2.

[0027] Figure 3 The synthesis route of the carboxyl-containing incompletely imidized polyimide in the embodiments is shown in Figure 3.

[0028] Figure 4 The nuclear magnetic resonance spectrum of the carboxyl-containing incompletely imidized polyimide prepared in Example 1 is shown in Figure 4.

[0029] Figure 5 The infrared spectrum of the carboxyl-containing incompletely imidized polyimide prepared in Example 1 is shown in Figure 5.

[0030] Figure 6 The molecular weight test chart of the carboxyl-containing incompletely imidized polyimide prepared in Example 1 is shown in Figure 6.

[0031] Figure 7 Picture of solubility test of carboxyl group-containing non-fully imidized polyimide prepared for Example 1 in a low boiling point solvent;

[0032] Figure 8 Picture of film forming solution prepared for Example 1 and Examples 49 to 51;

[0033] Figure 9 Picture of soluble polyimide / acrylic acid ion crosslinking type antifouling coating prepared for Example 1 and Examples 49 to 51;

[0034] Figure 10 Antifouling test result of carboxyl group-containing non-fully imidized polyimide prepared for Example 13;

[0035] Figure 11 Antifouling test result of soluble polyimide / acrylic acid ion crosslinking type antifouling coating prepared for Example 1;

[0036] Figure 12 First antibacterial test result of carboxyl group-containing non-fully imidized polyimide prepared for Example 13;

[0037] Figure 13 Second antibacterial test result of carboxyl group-containing non-fully imidized polyimide prepared for Example 13;

[0038] Figure 14 Antibacterial test result of soluble polyimide / acrylic acid ion crosslinking type antifouling coating (mass ratio = 1:5) prepared for Example 49;

[0039] Figure 15 Antibacterial test result of soluble polyimide / acrylic acid ion crosslinking type antifouling coating (mass ratio = 1:10) prepared for Example 1;

[0040] Figure 16 Antibacterial test result of soluble polyimide / acrylic acid ion crosslinking type antifouling coating (mass ratio = 1:15) prepared for Example 50;

[0041] Figure 17 First antibacterial test result of soluble polyimide / acrylic acid ion crosslinking type antifouling coating (mass ratio = 1:20) prepared for Example 51;

[0042] Figure 18 Second antibacterial test result of soluble polyimide / acrylic acid ion crosslinking type antifouling coating (mass ratio = 1:20) prepared for Example 51;

[0043] Figure 19TGA test results of the soluble polyimide / acrylic ion crosslinking type antifouling coating prepared for Example 1;

[0044] Figure 20 DSC test results of the soluble polyimide / acrylic ion crosslinking type antifouling coating prepared for Example 1;

[0045] Figure 21 Comparison of nuclear magnetic resonance spectra of the carboxyl-containing incompletely imidized polyimide and the soluble polyimide / acrylic ion crosslinking type antifouling coating prepared for Example 1;

[0046] Figure 22 Comparison of infrared spectra of the carboxyl-containing incompletely imidized polyimide, the soluble polyimide / acrylic ion crosslinking type antifouling coating prepared for Example 1 and zinc polyacrylate;

[0047] Figure 23 Contact angle test results of the carboxyl-containing incompletely imidized polyimide, the soluble polyimide / acrylic ion crosslinking type antifouling coating prepared for Example 1 (mass ratio = 1:10), the soluble polyimide / acrylic ion crosslinking type antifouling coating prepared for Example 50 (mass ratio = 1:15) and zinc polyacrylate. DETAILED DESCRIPTION

[0048] The present application provides a preparation method of a soluble polyimide / acrylic ion crosslinking type antifouling coating, comprising the following steps:

[0049] Mixing dianhydride monomers, diamine monomers and aprotic high-boiling point solvents to perform a polycondensation reaction to obtain a polyamide acid;

[0050] Placing the polyamide acid in a mixed solution of acetic anhydride, triethylamine and acetone to perform an incomplete imidization to obtain a carboxyl-containing incompletely imidized polyimide;

[0051] Mixing the carboxyl-containing incompletely imidized polyimide, a metal ion-containing polyacrylate and a low-boiling point solvent to obtain a film-forming solution; the metal ion-containing polyacrylate includes one or more of zinc polyacrylate and copper polyacrylate;

[0052] Performing film formation on the film-forming solution to obtain a soluble polyimide / acrylic ion crosslinking type antifouling coating.

[0053] The present application mixes a dianhydride monomer, a diamine monomer and a high-boiling-point aprotic solvent to perform a polycondensation reaction to obtain a polyamic acid (PAA). In the present application, the dianhydride monomer preferably includes one or more of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), pyromellitic dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride and 3,3',4,4'-benzophenonetetracarboxylic dianhydride; and the diamine monomer preferably includes one or more of 4,4'-oxydianiline (ODA), 3,4-oxydianiline, 3,3'-oxydianiline, 4,4'-oxydiphenyl sulfide, 3,4-oxydiphenyl sulfide, 3,3'-oxydiphenyl sulfide, 4,4'-oxydiphenyl sulfone, 3,4-oxydiphenyl sulfone, 3,3'-oxydiphenyl sulfone, 4,4'-diaminobiphenyl, 3,4-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4-diaminobenzophenone, 3,3'-diaminobenzophenone and 2,2-bis(4-aminophenyl)hexafluoropropane. In the present application, the molar ratio of the dianhydride monomer and the diamine monomer is preferably 0.4-0.77:1, and more preferably 0.51-0.65:1. In the present application, the high-boiling-point aprotic solvent preferably includes N-methylpyrrolidone (NMP), N,N-dimethylformamide, N,N-dimethylacetamide or m-cresol. In the present application, the total solid content of the dianhydride monomer and the diamine monomer in the mixed solution of the dianhydride monomer, the diamine monomer and the high-boiling-point aprotic solvent is preferably 5-20 wt%, and more preferably 15 wt%.

[0054] The present application preferably controls the molecular weight of the polyamic acid according to Formula I:

[0055] M ÷ repeating unit molecular weight = Xn = (1+r) / (1-r), Formula I;

[0056] In Formula I, M represents the molecular weight of the polyamic acid; Xn represents the degree of polymerization; and r represents the molar ratio of the anhydride monomer and the amine monomer.

[0057] In the present application, the polycondensation reaction is preferably performed at room temperature, and the time of the polycondensation reaction is preferably 20-30 h, and more preferably 24 h.

[0058] The present application preferably performs solvent exchange by placing the obtained reaction solution in water after the polycondensation reaction to separate the product, and then performs washing and drying of the product in sequence to obtain the polyamic acid. In the present application, the water is preferably ultrapure water. In the present application, the separation is preferably centrifugal separation. In the present application, the washing is preferably ultrapure water washing. In the present application, the temperature of the drying is preferably 60°C, and the time of the drying is preferably 24 h.

[0059] In a specific embodiment of the present application, the synthesis route of the polyamic acid is as shown in Figure 2 In the present application, the molecular weight of the polyamic acid is preferably 1500-5000, more preferably 2000-3000.

[0060] After obtaining the polyamic acid, the present application places the polyamic acid in a mixed solution of acetic anhydride, triethylamine and acetone, and performs incomplete imidization to obtain a carboxyl-containing polyimide that is not completely imidized. In the present application, the volume ratio of acetic anhydride, triethylamine and acetone in the mixed solution of acetic anhydride, triethylamine and acetone is preferably 1-3:1:10, more preferably 2:1:10, 1:1:10 or 3:1:10.

[0061] In the present application, the incomplete imidization is preferably performed at room temperature; the time of the incomplete imidization is preferably 0.5-3h, more preferably 2h.

[0062] After the incomplete imidization, the present application preferably adds water to the obtained system to precipitate the incomplete imidization product; the obtained incomplete imidization product is sequentially washed and dried to obtain a carboxyl-containing polyimide that is not completely imidized. In the present application, the washing is preferably centrifugal water washing. In the present application, the temperature of the drying is preferably 60°C; the time of the drying is preferably 24h.

[0063] In a specific embodiment of the present application, the synthesis route of the carboxyl-containing polyimide that is not completely imidized is as shown in Figure 3 The present application prepares a low-molecular-weight polyamic acid by controlling the raw material feeding ratio, and then prepares a low-molecular-weight polyimide with controllable imidization degree by controlling the ratio of the imidization reagent (acetic anhydride, triethylamine and acetone) and the time of incomplete imidization.

[0064] In a specific embodiment of the present application, the carboxyl-containing polyimide that is not completely imidized has a structural formula as shown in Formula II:

[0065]

[0066] In Formula II,

[0067]

[0068] x is 0.66 and y is 0.34.

[0069] After obtaining the carboxyl group-containing non-fully imidized polyimide, the present application mixes the carboxyl group-containing non-fully imidized polyimide, the metal ion-containing polyacrylate and the low-boiling point solvent to obtain a film-forming solution. In the present application, the molar ratio of the carboxyl group-containing non-fully imidized polyimide and the metal ion-containing polyacrylate is preferably 0.175-0.7:1, more preferably 0.35:1. In the present application, the metal ion-containing polyacrylate includes one or several of zinc polyacrylate and copper polyacrylate. In the present application, the molecular weight of the zinc polyacrylate is preferably 7000-8000, more preferably 7000. In the present application, the molecular weight of the copper polyacrylate is preferably 5000-10000, more preferably 7500.

[0070] In the present application, the low-boiling point solvent preferably includes tetrahydrofuran, dichloromethane or chloroform.

[0071] In the present application, the solid content of the film-forming solution is preferably 10-20wt%.

[0072] After obtaining the film-forming solution, the present application forms a film from the film-forming solution to obtain a soluble polyimide / acrylic acid ion crosslinking type antifouling coating. In the present application, the substrate for film formation is preferably an iron plate, glass or copper plate. In the present application, the film formation is preferably carried out at room temperature; the time for film formation is preferably 3-5h.

[0073] In a specific embodiment of the present application, the soluble polyimide / acrylic acid ion crosslinking type antifouling coating has a structural formula as shown in Formula III:

[0074]

[0075] In Formula III, n is in the range of 97-111.

[0076] The technical solutions in the present application will be described clearly and completely below in combination with the embodiments in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0077] Example 1

[0078] As Figure 1As shown, 9.8 mmol of ODA was added to a three-neck flask with stirring device and air guide device, 23.71 g of NMP was added, and stirring was performed in ice bath until complete dissolution; then 5 mmol of 6FDA was added in 4 equal portions with 5 min interval, and 3-5 mL of NMP was used to flush the weighing paper in the last time; the system was colorless when ODA was dissolved, and became light yellow after the addition of 6FDA as the reaction time was prolonged; ice bath was used for 2 h, and then normal temperature stirring was used for 24 h; after the reaction was completed, the reaction liquid was poured into ultrapure water, stirring was performed for 3.5 h for solvent exchange, and then the product was separated by centrifuge; ultrapure water was used for washing 6 times until the supernatant was clear; then drying was performed in a 60°C oven for 24 h, and polyamic acid (PAA) with a molecular weight of 2000 was obtained.

[0079] 1 g of dried PAA was weighed and added to a mixed solution of 24.18 mL of acetic anhydride, triethylamine and acetone with a volume ratio of 2:1:10, the soaking time was 2 h, 5 mL of the mixed solution was drawn, and 100 mL of water was added to the mixed solution to precipitate the product; then the product was separated by centrifuge, the crude product was washed with water 6 times, and the product was separated by centrifuge again until the supernatant was colorless and free of solid product; then drying was performed in a 60°C oven for 24 h, and the target product, i.e., carboxyl-containing incompletely imidized polyimide, was obtained in a light yellow color.

[0080] 0.2 g of the carboxyl-containing incompletely imidized polyimide and 2 g of zinc polyacrylate (molecular weight 7000) were added to tetrahydrofuran under ultrasonic condition, mixed for 8 min to obtain a film-forming solution with a solid content of 10 wt%; it was cast on an iron plate and dried at room temperature for 4 h to obtain a soluble polyimide / acrylic acid ionic crosslinking type antifouling coating.

[0081] Examples 2-48

[0082] The preparation method was basically the same as that of Example 1, and the differences were shown in Table 1.

[0083] Table 1: Preparation process parameters of examples

[0084]

[0085]

[0086]

[0087] Example 49

[0088] The preparation method was basically the same as that of Example 1, and the difference was only that the amount of zinc polyacrylate was adjusted to 1 g.

[0089] Example 50

[0090] The preparation method is basically the same as that in Example 1, except that the amount of zinc polyacrylate is adjusted to 3g.

[0091] Example 51

[0092] The preparation method is basically the same as that in Example 1, except that the amount of zinc polyacrylate is adjusted to 4g.

[0093] Test case

[0094] The solubility of the carboxyl-containing, unimideated polyimides prepared in Examples 1-48 is shown in Table 2.

[0095] Table 2 Solubility of polyimides prepared in the examples

[0096]

[0097]

[0098]

[0099] In Table 2, + indicates soluble; +- indicates partially soluble; and - indicates insoluble. Table 2 shows that all examples with a molecular weight above 2000 are insoluble in solvents such as tetrahydrofuran, dichloromethane, xylene, and isopropanol. Examples with molecular weights of 1500 and 2000 exhibit excellent solubility in tetrahydrofuran. Except for Example 8, which shows slight insolubility in dichloromethane, the other examples with molecular weights of 1500 and 2000 are soluble in dichloromethane quite well. Generally, polymers with higher molecular weights have better mechanical properties. Considering that the coating is susceptible to seawater impact after being applied to ship antifouling applications, it was ultimately decided to use polyimide with a molecular weight of 2000 for subsequent testing.

[0100] The NMR spectrum of the carboxyl-containing, unimideated polyimide prepared in Example 1 is shown below. Figure 4 As shown, the formula for calculating the degree of imidization is: imidization ratio = 1 - (A1 / A2) ÷ (A1′ / A2′), where A1 represents the integral area of ​​the amide peak (-NH) in the NMR spectrum of the polyimide, A2 represents the total integral area of ​​hydrogens on the benzene ring in the NMR spectrum of the polyimide, A1′ represents the theoretical number of -NH groups in the polyamic acid (theoretical number is 2), and A2′ represents the number of hydrogens on the benzene ring in the polyamic acid (theoretical number is 14). The calculated degree of imidization is approximately 0.66. The successful synthesis of the target polymer can be confirmed by the NMR spectrum and the assignment of each hydrogen chemical shift in existing literature. Due to the high reactivity of the carboxyl hydrogen, no corresponding hydrogen peak was found. 1HNMR (400MHz, DMSO-d6) δ9.94(s,2H),8.14(m,4H),7.92(d,2H),7.70(d,2H),7.60(dd,4H),7.45(d,2H),7.36(d,2H),7.20(d,4H),7.03(m,8H).

[0101] The infrared spectrum of the carboxyl-containing, unimideated polyimide prepared in Example 1 is shown below. Figure 5 As shown, by Figure 5 It can be seen that the infrared spectrum of polyimide retains hydroxyl groups (3000 cm⁻¹). -1 ), amide stretching vibration peak (3350cm) -1 ) and the carbonyl peak of the carboxyl group (1680 cm⁻¹) -1 This indicates that the polymer is not fully imidized and still retains carboxyl groups that can coordinate with zinc ions. FT-IR (KBr, cm⁻¹) -1 ):1600-1725cm -1 (C=O), 3000cm -1 (OH), 3350cm -1 (NH).

[0102] The molecular weight of the carboxyl-containing, unimideated polyimide prepared in Example 1 is as follows: Figure 6 As shown, by Figure 6 It can be seen that the actual molecular weight is not significantly different from the planned molecular weight. The molecular weight of the polymer prepared according to theoretical calculations is approximately 2700. The experimentally measured molecular weight is larger than the theoretically calculated molecular weight. This is because the raw materials used in the experiment, 4,4'-(hexafluoroisopropene)phthalic anhydride and diaminodiphenyl ether, have high reactivity at the experimental temperature, and the reaction process generates molecular chains that are longer than theoretically calculated.

[0103] The solubility of the carboxyl-containing, unimideated polyimide prepared in Example 1 in low-boiling-point solvents is as follows: Figure 7 As shown, by Figure 7 It can be seen that the polymer has poor solubility in isopropanol, isobutanol, n-butanol, xylene, and o-xylene, is partially soluble in acetone, and is soluble in chloroform.

[0104] The film-forming solutions prepared in Examples 1 and 49-51 are as follows: Figure 8 As shown, Figure 8 The plastic tubes from left to right represent: a mixture of unimideated polyimide containing carboxyl groups and zinc polyacrylate in mass ratios of 1:5, 1:10, 1:15, and 1:20 dissolved in tetrahydrofuran (each ratio was tested three times). Figure 8It can be seen that the polyimide / acrylate ionic crosslinking complex dissolves well in tetrahydrofuran. Furthermore, increasing the amount of zinc polyacrylate added does not affect its solubility in tetrahydrofuran.

[0105] The soluble polyimide / acrylic ion-crosslinked antifouling coatings prepared in Examples 1 and 49-51 are as follows: Figure 9 As shown, Figure 9 In this context, 0.25 represents the film-forming properties test of the soluble polyimide / acrylic ion-crosslinked antifouling coating prepared in Example 49 (mass ratio = 1:5); 0.3 represents the film-forming properties test of the soluble polyimide / acrylic ion-crosslinked antifouling coating prepared in Example 1 (mass ratio = 1:10); 0.35 ( Figure 9 The top left corner indicates the film-forming properties test of the soluble polyimide / acrylic ion-crosslinked antifouling coating prepared in Example 50 (mass ratio = 1:15); 0.4 indicates the film-forming properties test of the soluble polyimide / acrylic ion-crosslinked antifouling coating prepared in Example 51 (mass ratio = 1:20). Figure 9 It can be seen that polyimide / polyacrylic acid mixtures of different proportions all have good film-forming properties.

[0106] Figure 10 The antifouling test results are for the carboxyl-containing, unimideated, fully polyimide prepared in Example 13; Figure 11 The antifouling test results are for the soluble polyimide / acrylic ion-crosslinked antifouling coating prepared in Example 1. Figure 10-11 It can be seen that the soluble polyimide / acrylic ion-crosslinked antifouling coating has good antifouling performance.

[0107] Figure 12 The results of the first antibacterial test of the carboxyl-containing, unimideated, fully-imideated polyimide prepared in Example 13; Figure 13 The results of the second antimicrobial test are for the carboxyl-containing, unimideated, fully polyimide prepared in Example 13; Figure 14 The antibacterial test results for the soluble polyimide / acrylic ion-crosslinked antifouling coating (mass ratio = 1:5) prepared in Example 49; Figure 15 The antibacterial test results are for the soluble polyimide / acrylic ion-crosslinked antifouling coating (mass ratio = 1:10) prepared in Example 1. Figure 16 The antibacterial test results of the soluble polyimide / acrylic ion-crosslinked antifouling coating (mass ratio = 1:15) prepared in Example 50; Figure 17 The results of the first antibacterial test of the soluble polyimide / acrylic ion-crosslinked antifouling coating (mass ratio = 1:20) prepared in Example 51; Figure 18The second antibacterial test results of the soluble polyimide / acrylic acid ion crosslinking type antifouling coating (mass ratio = 1:20) prepared in Example 51. Inhibition zone analysis: the inhibition zone test was performed using a culture dish with a diameter of 9 cm and a sample with a side length of 2 cm. Figure 12 The inhibition zone diameter was 2.4 cm, Figure 13 The inhibition zone diameter was 2.4 cm, Figure 14 The inhibition zone diameter was 3.1 cm, Figure 15 The inhibition zone diameter was 3.4 cm, Figure 16 The inhibition zone diameter was 3.1 cm, Figure 17 The inhibition zone diameter was 2.7 cm, Figure 18 The inhibition zone diameter was 3.2 cm. As can be seen from the figure, after the addition of zinc acrylate, the antibacterial diameter of the composite material has been significantly increased, and the antibacterial effect of the soluble polyimide / acrylic acid ion crosslinking type antifouling coating (mass ratio = 1:10) prepared in Example 1 is the best. It shows that the addition of zinc acrylate can effectively increase the antibacterial ability of the composite material.

[0108] Figure 19 TGA test results of the soluble polyimide / acrylic acid ion crosslinking type antifouling coating (polyimide / zinc acrylate ion crosslinking composite material) prepared in Example 1; Figure 20 DSC test results of the soluble polyimide / acrylic acid ion crosslinking type antifouling coating (polyimide / zinc acrylate ion crosslinking composite material) prepared in Example 1. From Figure 19-20 It can be seen that the weight loss of 30-343℃ is mainly caused by the breakage of the polyacrylic acid zinc main chain, the loss of small molecules such as solvents (such as water, tetrahydrofuran), etc. The weight loss of 343-617℃ is mainly caused by the group falling off of polyimide, and the weight loss of 617-800℃ is mainly caused by the breakage of the polyimide main chain. The glass transition temperature of the composite material is 243℃, which has good high temperature resistance.

[0109] Figure 21 The nuclear magnetic resonance spectrum of the carboxyl-containing non-imidized polyimide (PI) and the soluble polyimide / acrylic acid ion crosslinking type antifouling coating (mixed coordination) prepared in Example 1 is compared. After mixing the polyimide with the polyacrylic acid zinc, the peak area of H11 (amide peak) / H5 / H7 / H9 in the nuclear magnetic resonance spectrum Figure 21 is obviously reduced and the peak type has changed obviously, which shows that the ion crosslinking between the polyimide and the polyacrylic acid zinc is successfully formed.

[0110] Figure 22Comparing the infrared spectra of the carboxyl-containing non-fully imidized polyimide (PI) prepared in Example 1, the soluble polyimide / acrylic ionic crosslinking type antifouling coating (mixed coordination) prepared in Example 1, and the zinc polyacrylate, the infrared spectra before and after coordination Figure 22 It can be seen that the carbonyl peak of the carboxyl group in the polyimide at 1680 cm -1 -1 shifted to 1662 cm -1 -1 after coordination, indicating that the carbonyl of the carboxyl group in the polyimide participated in the coordination. In addition, the characteristic peaks of zinc polyacrylate appeared at 2962 cm -1 and 2874 cm -1 -1 in the polyimide after coordination, which also indicated the successful formation of ionic crosslinking.

[0111] Figure 23 Contact angle test results of the carboxyl-containing non-fully imidized polyimide prepared in Example 1, the soluble polyimide / acrylic ionic crosslinking type antifouling coating prepared in Example 1 (mass ratio = 1:10), the soluble polyimide / acrylic ionic crosslinking type antifouling coating prepared in Example 50 (mass ratio = 1:15), and the zinc polyacrylate. From the results Figure 23 It can be seen that as the content of zinc polyacrylate increases, the contact angle shows a downward trend, but the overall hydrophobicity is good and is higher than 85°.

[0112] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, several improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing a soluble polyimide / acrylic ion crosslinking type antifouling coating, comprising the following steps: mixing a dianhydride monomer, a diamine monomer and a high-boiling-point aprotic solvent to perform a polycondensation reaction to obtain a polyamic acid; controlling a molecular weight of the polyamic acid according to Formula I: M ÷ molecular weight of repeating unit = Xn = (1 + r) / (1 - r), Formula I; wherein M represents the molecular weight of the polyamic acid; Xn represents a degree of polymerization; and r represents a molar ratio of the dianhydride monomer to the diamine monomer; placing the polyamic acid in a mixed solution of acetic anhydride, triethylamine and acetone to perform an incomplete imidization to obtain a carboxyl-containing incompletely imidized polyimide; mixing the carboxyl-containing incompletely imidized polyimide, a metal ion-containing polyacrylate and a low-boiling-point solvent to obtain a film-forming solution; the metal ion-containing polyacrylate comprises one or more of zinc polyacrylate and copper polyacrylate; and a molar ratio of the carboxyl-containing incompletely imidized polyimide to the metal ion-containing polyacrylate is 0.175-0.7: 1; and performing film formation on the film-forming solution to obtain the soluble polyimide / acrylic ion crosslinking type antifouling coating. The dianhydride monomer comprises one or more of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride, pyromellitic dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride and 3,3',4,4'-benzophenonetetracarboxylic dianhydride. The diamine monomer comprises one or more of 4,4'-oxydianiline, 3,4-oxydianiline, 3,3'-oxydianiline, 4,4'-diaminodiphenyl sulfide, 3,4-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,4-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobiphenyl, 3,4-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4-diaminobenzophenone, 3,3'-diaminobenzophenone and 2,2-bis(4-aminophenyl) hexafluoropropane. The polycondensation reaction is performed at room temperature; and the polycondensation reaction is performed for 20-30 hours. The volume ratio of acetic anhydride, triethylamine and acetone in the mixed solution of acetic anhydride, triethylamine and acetone is 1-3: 1:

10. The incomplete imidization is performed at room temperature; and the incomplete imidization is performed for 0.5-3 hours. The low-boiling-point solvent comprises tetrahydrofuran, dichloromethane or chloroform. The solid content of the film-forming solution is 10-20 wt%.

2. The production method according to claim 1, characterized by, The film formation is performed at room temperature; and the film formation is performed for 3-5 hours. ​ 3. The preparation method according to claim 1, characterized in that, ​ 4. The method of claim 1, wherein, ​ 5. The production method according to claim 1 or 4, characterized by, ​ 6. The method of claim 1, wherein, ​ 7. The production method according to claim 1 or 6, characterized by, ​ 8. The preparation method according to claim 1, characterized in that, ​

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