A trifluorochloroethylene copolymer anticorrosion adhesive film

Abstract

The present application relates to the technical field of anticorrosion adhesive film, in particular to a trifluorochloroethylene copolymer anticorrosion adhesive film; the adhesive film is composed of trifluorochloroethylene copolymer, epoxy resin, crosslinking agent, curing accelerator, modified functional filler, modified interface modifier, leveling agent and solvent; the modified functional filler is prepared by reacting grafted polyether segments with isocyanate-terminated polyether polyols after surface activation of glass flake by gamma-aminopropyl triethoxysilane; the modified interface modifier is prepared by chelating coordination of aniline and zinc nitrate after condensation of N-(2-aminoethyl)-3-aminopropyl trimethoxysilane with p-phenylenedimethylaldehyde to form a Schiff base pre-polymer; the combination of the modified functional filler and the modified interface modifier enables the adhesive film to have both shielding and interface protection functions, and has good salt spray resistance, adhesion and impact resistance.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating film technology, specifically to an anti-corrosion coating film of trifluorochloroethylene copolymer. Background Technology

[0002] Trichlorofluoroethylene copolymers possess excellent weather resistance, chemical resistance, and salt spray corrosion resistance, making coatings made from them a promising base resin for corrosion protection of steel structures. To balance adhesion and mechanical properties, current technologies typically blend trichlorofluoroethylene copolymers with epoxy resins, enhancing the coating's barrier properties by adding flake-like fillers, and supplementing with silane coupling agents or adhesion promoters to improve the interfacial bonding between the coating and the metal substrate. This component combination has become a common technical approach in solvent-based fluorocarbon anti-corrosion coating materials.

[0003] Chinese Patent 201811434075.5, entitled "A Low-Surface-Treatment Anti-corrosion Transparent Coating for Steel Structures and Coating Process," discloses a coating consisting of a primer, an intermediate coat, and a topcoat. The primer is a two-component epoxy resin containing modifiers such as penetrants, adhesion promoters, light stabilizers, nano-oxides, and rust converters. The intermediate coat is a two-component acrylic or polyurethane, and the topcoat is a two-component polysiloxane or fluorocarbon resin. This solution employs a multi-layer coating structure, achieving a balance of adhesion, corrosion resistance, and weather resistance through the functional division of each layer.

[0004] The aforementioned scheme, as a multi-layer coating system, faces insufficient adaptability in single-layer adhesive film configurations. The interfacial compatibility between flake fillers and fluorocarbon resins differs significantly, making it difficult to control the uniformity of filler dispersion in the resin, thus affecting coating density. Silane coupling agents, which are adhesion promoters, primarily provide interfacial bonding, but their sustained protective capability under long-term penetration of corrosive media is limited. Therefore, improving the interfacial bonding quality between flake fillers and the resin matrix in single-layer adhesive films and enhancing the long-term protective effect of the coating at the metal substrate interface are technical problems that need to be solved for this type of material. Summary of the Invention

[0005] (a) Technical problems to be solved The purpose of this invention is to provide a trifluorochloroethylene copolymer anti-corrosion coating film to solve the problems of poor salt spray resistance, insufficient adhesion and low impact resistance of existing coating films.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: A trifluorochloroethylene copolymer anti-corrosion coating film comprises the following raw materials in parts by weight: 90-110 parts trifluorochloroethylene copolymer, 15-25 parts epoxy resin, 8-15 parts crosslinking agent, 0.2-0.8 parts curing accelerator, 15-35 parts modified functional filler, 3-6 parts modified interface modifier, 0.8-1.5 parts leveling agent, and 80-100 parts xylene.

[0007] Furthermore, the modified functional filler is prepared by means of the following steps: A1. Add 80-120 parts of glass flakes and 10-12 parts of γ-aminopropyltriethoxysilane to a mixed solvent of anhydrous ethanol and deionized water, adjust the pH of the system to 4.5-5.5 with acetic acid, heat the reaction, filter, wash, and vacuum dry after the reaction to obtain silanized activated filler. A2. Under nitrogen protection, 90-110 parts of the silanized activated filler obtained in step A1 and 30-35 parts of isocyanate-terminated polyether polyol are added to 350-450 parts of dry toluene, and 0.5-1.5 parts of dibutyltin dilaurate are added. The mixture is heated to react, and after the reaction is completed, it is filtered, washed, and vacuum dried to obtain the modified functional filler.

[0008] Furthermore, the modified interface modifier is prepared by the following steps: B1. Dissolve 90-110 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in tetrahydrofuran, add 28-32 parts of tetrahydrofuran solution of terephthalaldehyde dropwise under nitrogen protection, stir the reaction, and distill under reduced pressure after the reaction is completed to obtain Schiff alkalized prepolymer. B2. Dissolve 90-110 parts of the Schiff alkalized prepolymer obtained in step B1 in ethanol, add 6-8 parts of aniline, stir well, add 13-17 parts of zinc nitrate ethanol solution dropwise, adjust the pH to 4.2-4.8 with nitric acid, heat the reaction, distill under reduced pressure after the reaction is completed, and dry under vacuum to obtain the modified interface modifier.

[0009] Furthermore, the volume ratio of anhydrous ethanol to deionized water in the mixed solvent is (8-10):1, the heating reaction temperature is 50-60℃, the time is 2-3h, and the vacuum drying temperature is 80-100℃.

[0010] Furthermore, the heating reaction is carried out at a temperature of 65-75°C for 3-4 hours, and the vacuum drying is carried out at a temperature of 65-75°C.

[0011] Furthermore, the stirring reaction is carried out at a temperature of 28-32°C for 2-3 hours, and the mass fraction of terephthalaldehyde in the tetrahydrofuran solution is 15%-25%.

[0012] Furthermore, the heating reaction is carried out at a temperature of 50-55°C for 4-5 hours, the vacuum drying is carried out at a temperature of 42-48°C, and the zinc nitrate in the ethanol solution is 20%-35% by mass.

[0013] Furthermore, the trifluorochloroethylene copolymer is a trifluorochloroethylene-vinyl ester copolymer, Lumiflon LF-200.

[0014] Furthermore, the epoxy resin is bisphenol A type epoxy resin E-44.

[0015] Furthermore, the crosslinking agent is methylated melamine-formaldehyde resin Cymel 303.

[0016] Furthermore, the curing accelerator is p-toluenesulfonic acid monohydrate.

[0017] Furthermore, the leveling agent is a polyether-modified silicone leveling agent BYK-331.

[0018] (iii) Beneficial technical effects Compared with the prior art, the beneficial effects of the present invention are: (1) In this invention, glass flakes are surface-activated with γ-aminopropyltriethoxysilane, and then stable chemical bonds are formed by the condensation of silane end groups with hydroxyl groups on the filler surface. Then, isocyanate-terminated polyether polyols are used to graft polyether segments onto the surface amino groups to obtain modified functional fillers. This modification method changes the filler surface from hydrophilic to hydrophobic, significantly improving its compatibility with trichlorofluoroethylene copolymers and epoxy resin matrices. The filler is uniformly dispersed in the coating, reducing micropores at the filler-resin interface and enhancing the coating's shielding and impact resistance.

[0019] (2) In this invention, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane is condensed with terephthalaldehyde to form a prepolymer containing a Schiff base structure, which is then coordinated and chelated with aniline and zinc nitrate to obtain a modified interface modifier. This modifier retains the chemical bonding function of the silane end groups to the metal substrate, and the introduced Schiff base-zinc ion chelate structure can slowly release zinc ions when corrosion occurs, giving the coating interface active protection capability and extending the service life of the coating in corrosive environments.

[0020] (3) The present invention combines modified functional filler with modified interface modifier. The filler forms a dense shielding layer in the coating body, effectively blocking the corrosive medium from penetrating towards the substrate. The interface modifier forms a protective layer on the metal surface with chemical bonding and active corrosion inhibition, which inhibits the trace amount of corrosive medium that has penetrated to the interface. The coating body protection and interface protection complement each other, and the overall anti-corrosion effect is better than that of a single modification scheme.

[0021] (4) The present invention uses trifluorochloroethylene copolymer and epoxy resin as the base resin. The trifluorochloroethylene copolymer gives the coating excellent weather resistance and chemical resistance, while the epoxy resin provides good adhesion and bulk strength. Combined with methyl etherified melamine formaldehyde resin crosslinking agent, it forms an interpenetrating network structure. The coating has both the durability of fluorocarbon resin and the mechanical properties of epoxy resin. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] A trifluorochloroethylene copolymer anti-corrosion coating film comprises the following raw materials in parts by weight: 90 parts trifluorochloroethylene-vinyl ester copolymer Lumiflon LF-200, 15 parts bisphenol A type epoxy resin E-44, 8 parts methylated melamine formaldehyde resin Cymel 303, 0.2 parts p-toluenesulfonic acid monohydrate, 15 parts modified functional filler, 3 parts modified interface modifier, 0.8 parts polyether modified silicone leveling agent BYK-331, and 80 parts xylene.

[0025] The modified functional filler is prepared by the following steps: A1. 80 parts of glass flakes and 10 parts of γ-aminopropyltriethoxysilane were added to a mixed solvent of 500 parts of anhydrous ethanol and deionized water. The pH of the system was adjusted to 4.5 with acetic acid, and the reaction was carried out under heat. The volume ratio of anhydrous ethanol to deionized water in the mixed solvent was 8:1. The temperature of the reaction was 50°C and the time was 3 hours. After the reaction was completed, the mixture was filtered, the filter cake was washed with ethanol, and then dried under vacuum at 80°C to obtain the silanized activated filler. A2. Under nitrogen protection, 90 parts of the silanized activated filler obtained in step A1 and 30 parts of isocyanate-terminated polyether polyol were added to 350 parts of dry toluene, and 0.5 parts of dibutyltin dilaurate were added. The mixture was heated to react at 65°C for 4 hours. After the reaction was completed, the mixture was filtered, the filter cake was washed with toluene, and then dried under vacuum at 65°C to obtain the modified functional filler.

[0026] The modified interface modifier is prepared by the following steps: B1. Dissolve 90 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in 200 parts of tetrahydrofuran. Under nitrogen protection, add 28 parts of a tetrahydrofuran solution of terephthalaldehyde dropwise and stir the reaction. The terephthalaldehyde in the tetrahydrofuran solution has a mass fraction of 15%. The stirring reaction is carried out at a temperature of 28°C for 3 hours. After the reaction is completed, remove the solvent by vacuum distillation to obtain the Schiff alkalized prepolymer. B2. Dissolve 90 parts of the Schiff alkalized prepolymer obtained in step B1 in 300 parts of ethanol, add 6 parts of aniline, stir well, add 13 parts of zinc nitrate in ethanol solution dropwise, adjust the pH to 4.2 with nitric acid, and heat the reaction. The mass fraction of zinc nitrate in the zinc nitrate in the ethanol solution is 20%. The heating reaction temperature is 50°C and the time is 5 hours. After the reaction is completed, remove the solvent by vacuum distillation and dry under vacuum at 42°C to obtain the modified interface modifier.

[0027] Example 2

[0028] A trifluorochloroethylene copolymer anti-corrosion coating film comprises the following raw materials in parts by weight: 95 parts trifluorochloroethylene-vinyl ester copolymer Lumiflon LF-200, 18 parts bisphenol A type epoxy resin E-44, 10 parts methylated melamine formaldehyde resin Cymel 303, 0.35 parts p-toluenesulfonic acid monohydrate, 20 parts modified functional filler, 3.5 parts modified interface modifier, 1.0 part polyether modified silicone leveling agent BYK-331, and 85 parts xylene.

[0029] The modified functional filler is prepared by the following steps: A1. 90 parts of glass flakes and 10.5 parts of γ-aminopropyltriethoxysilane were added to a mixed solvent of 575 parts of anhydrous ethanol and deionized water. The pH of the system was adjusted to 4.8 with acetic acid, and the reaction was carried out under heat. The volume ratio of anhydrous ethanol to deionized water in the mixed solvent was 8.5:1. The temperature of the reaction was 53°C and the time was 2.7 h. After the reaction was completed, the mixture was filtered, the filter cake was washed with ethanol, and then dried under vacuum at 85°C to obtain the silanized activated filler. A2. Under nitrogen protection, 95 parts of the silanized activated filler obtained in step A1 and 31.5 parts of isocyanate-terminated polyether polyol were added to 375 parts of dry toluene, and 0.75 parts of dibutyltin dilaurate were added. The mixture was heated to react at a temperature of 68°C for 3.7 hours. After the reaction was completed, the mixture was filtered, the filter cake was washed with toluene, and then dried under vacuum at 68°C to obtain the modified functional filler.

[0030] The modified interface modifier is prepared by the following steps: B1. Dissolve 95 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in 225 parts of tetrahydrofuran. Under nitrogen protection, add 29 parts of a tetrahydrofuran solution of terephthalaldehyde dropwise and stir the reaction. The terephthalaldehyde in the tetrahydrofuran solution has a mass fraction of 17.5%. The stirring reaction is carried out at a temperature of 29°C for 2.7 h. After the reaction is completed, remove the solvent by vacuum distillation to obtain the Schiff alkalized prepolymer. B2. Dissolve 95 parts of the Schiff alkalized prepolymer obtained in step B1 in 350 parts of ethanol, add 6.5 parts of aniline, stir well, add 14 parts of an ethanol solution of zinc nitrate dropwise, adjust the pH to 4.35 with nitric acid, and heat the reaction. The mass fraction of zinc nitrate in the ethanol solution of zinc nitrate is 24%. The heating reaction temperature is 51.5℃ and the time is 4.7h. After the reaction is completed, remove the solvent by vacuum distillation and dry under vacuum at 43.5℃ to obtain the modified interface modifier.

[0031] Example 3

[0032] A trifluorochloroethylene copolymer anti-corrosion coating film comprises the following raw materials in parts by weight: 100 parts trifluorochloroethylene-vinyl ester copolymer Lumiflon LF-200, 20 parts bisphenol A type epoxy resin E-44, 12 parts methylated melamine formaldehyde resin Cymel 303, 0.5 parts p-toluenesulfonic acid monohydrate, 25 parts modified functional filler, 4.5 parts modified interface modifier, 1.15 parts polyether modified silicone leveling agent BYK-331, and 90 parts xylene.

[0033] The modified functional filler is prepared by the following steps: A1. 100 parts of glass flakes and 11 parts of γ-aminopropyltriethoxysilane were added to a mixed solvent of 650 parts of anhydrous ethanol and deionized water. The pH of the system was adjusted to 5.0 with acetic acid, and the reaction was carried out under heat. The volume ratio of anhydrous ethanol to deionized water in the mixed solvent was 9:1. The temperature of the reaction was 55°C and the time was 2.5 h. After the reaction was completed, the mixture was filtered, the filter cake was washed with ethanol, and then dried under vacuum at 90°C to obtain the silanized activated filler. A2. Under nitrogen protection, 100 parts of the silanized activated filler obtained in step A1 and 32.5 parts of isocyanate-terminated polyether polyol were added to 400 parts of dry toluene, and 1.0 part of dibutyltin dilaurate was added. The mixture was heated to react at 70°C for 3.5 hours. After the reaction was completed, the mixture was filtered, the filter cake was washed with toluene, and then dried under vacuum at 70°C to obtain the modified functional filler.

[0034] The modified interface modifier is prepared by the following steps: B1. Dissolve 100 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in 250 parts of tetrahydrofuran. Under nitrogen protection, add 30 parts of a tetrahydrofuran solution of terephthalaldehyde dropwise and stir the reaction. The terephthalaldehyde in the tetrahydrofuran solution has a mass fraction of 20%. The stirring reaction is carried out at 30°C for 2.5 hours. After the reaction is completed, remove the solvent by vacuum distillation to obtain the Schiff alkalized prepolymer. B2. Dissolve 100 parts of the Schiff alkalized prepolymer obtained in step B1 in 400 parts of ethanol, add 7 parts of aniline, stir well, add 15 parts of an ethanol solution of zinc nitrate dropwise, adjust the pH to 4.5 with nitric acid, and heat the reaction. The mass fraction of zinc nitrate in the ethanol solution of zinc nitrate is 27.5%, the heating temperature is 52.5℃, and the time is 4.5h. After the reaction is completed, remove the solvent by vacuum distillation, and dry under vacuum at 45℃ to obtain the modified interface modifier.

[0035] Example 4

[0036] A trifluorochloroethylene copolymer anti-corrosion coating film comprises the following raw materials in parts by weight: 105 parts trifluorochloroethylene-vinyl ester copolymer Lumiflon LF-200, 22 parts bisphenol A type epoxy resin E-44, 14 parts methylated melamine formaldehyde resin Cymel 303, 0.65 parts p-toluenesulfonic acid monohydrate, 30 parts modified functional filler, 5.5 parts modified interface modifier, 1.35 parts polyether modified silicone leveling agent BYK-331, and 95 parts xylene.

[0037] The modified functional filler is prepared by the following steps: A1. 110 parts of glass flakes and 11.5 parts of γ-aminopropyltriethoxysilane were added to a mixed solvent of 725 parts of anhydrous ethanol and deionized water. The pH of the system was adjusted to 5.2 with acetic acid, and the reaction was carried out under heat. The volume ratio of anhydrous ethanol to deionized water in the mixed solvent was 9.5:1. The temperature of the reaction was 58°C and the time was 2.3 h. After the reaction was completed, the mixture was filtered, the filter cake was washed with ethanol, and then dried under vacuum at 95°C to obtain the silanized activated filler. A2. Under nitrogen protection, 105 parts of the silanized activated filler obtained in step A1 and 33.5 parts of isocyanate-terminated polyether polyol were added to 425 parts of dry toluene, and 1.25 parts of dibutyltin dilaurate were added. The mixture was heated to react at a temperature of 73°C for 3.3 hours. After the reaction was completed, the mixture was filtered, the filter cake was washed with toluene, and then vacuum dried at 73°C to obtain the modified functional filler.

[0038] The modified interface modifier is prepared by the following steps: B1. Dissolve 105 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in 275 parts of tetrahydrofuran. Under nitrogen protection, add 31 parts of a tetrahydrofuran solution of terephthalaldehyde dropwise and stir the reaction. The terephthalaldehyde in the tetrahydrofuran solution has a mass fraction of 22.5%. The stirring reaction is carried out at a temperature of 31°C for 2.3 hours. After the reaction is completed, remove the solvent by vacuum distillation to obtain the Schiff alkalized prepolymer. B2. Dissolve 105 parts of the Schiff alkalized prepolymer obtained in step B1 in 450 parts of ethanol, add 7.5 parts of aniline, stir well, add 16 parts of an ethanol solution of zinc nitrate dropwise, adjust the pH to 4.65 with nitric acid, and heat the reaction. The mass fraction of zinc nitrate in the ethanol solution of zinc nitrate is 31%, the heating temperature is 54°C, and the time is 4.3 h. After the reaction is completed, remove the solvent by vacuum distillation, and dry under vacuum at 46.5°C to obtain the modified interface modifier.

[0039] Example 5

[0040] A trifluorochloroethylene copolymer anti-corrosion coating film comprises the following raw materials in parts by weight: 110 parts trifluorochloroethylene-vinyl ester copolymer Lumiflon LF-200, 25 parts bisphenol A type epoxy resin E-44, 15 parts methylated melamine formaldehyde resin Cymel 303, 0.8 parts p-toluenesulfonic acid monohydrate, 35 parts modified functional filler, 6 parts modified interface modifier, 1.5 parts polyether modified silicone leveling agent BYK-331, and 100 parts xylene.

[0041] The modified functional filler is prepared by the following steps: A1. 120 parts of glass flakes and 12 parts of γ-aminopropyltriethoxysilane were added to a mixed solvent of 800 parts of anhydrous ethanol and deionized water. The pH of the system was adjusted to 5.5 with acetic acid. The reaction was carried out under heat. The volume ratio of anhydrous ethanol to deionized water in the mixed solvent was 10:1. The temperature of the reaction was 60°C and the time was 2 hours. After the reaction was completed, the mixture was filtered, the filter cake was washed with ethanol, and the mixture was dried under vacuum at 100°C to obtain the silanized activated filler. A2. Under nitrogen protection, 110 parts of the silanized activated filler obtained in step A1 and 35 parts of isocyanate-terminated polyether polyol were added to 450 parts of dry toluene, and 1.5 parts of dibutyltin dilaurate were added. The mixture was heated to react at 75°C for 3 hours. After the reaction was completed, the mixture was filtered, the filter cake was washed with toluene, and then dried under vacuum at 75°C to obtain the modified functional filler.

[0042] The modified interface modifier is prepared by the following steps: B1. Dissolve 110 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in 300 parts of tetrahydrofuran. Under nitrogen protection, add 32 parts of a tetrahydrofuran solution of terephthalaldehyde dropwise and stir the reaction. The terephthalaldehyde in the tetrahydrofuran solution has a mass fraction of 25%. The stirring reaction is carried out at a temperature of 32°C for 2 hours. After the reaction is completed, the solvent is removed by vacuum distillation to obtain the Schiff alkalized prepolymer. B2. Dissolve 110 parts of the Schiff alkalized prepolymer obtained in step B1 in 500 parts of ethanol, add 8 parts of aniline, stir well, add 17 parts of an ethanol solution of zinc nitrate dropwise, adjust the pH to 4.8 with nitric acid, and heat the reaction. The mass fraction of zinc nitrate in the ethanol solution of zinc nitrate is 35%. The heating temperature is 55°C and the time is 4 hours. After the reaction is completed, remove the solvent by vacuum distillation and dry under vacuum at 48°C to obtain the modified interface modifier.

[0043] Comparative Example 1 A trifluorochloroethylene copolymer anti-corrosion coating film, compared with the anti-corrosion coating film in Example 1, is mainly different in that: an equal amount of unmodified glass flakes is used to replace the modified functional filler in this comparative example, while the other components and preparation methods are completely consistent with those in Example 1.

[0044] Comparative Example 2 A trifluorochloroethylene copolymer anti-corrosion coating film, compared with the anti-corrosion coating film in Example 1, is mainly different in that: in this comparative example, an equal amount of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane is used instead of the modified interface modifier, and the other components and preparation methods are completely consistent with those in Example 1.

[0045] Comparative Example 3 A trifluorochloroethylene copolymer anti-corrosion coating film, compared with the anti-corrosion coating film in Example 1, is mainly different in that: in this comparative example, an equal amount of unmodified glass flakes is used instead of modified functional filler, and an equal amount of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane is used instead of modified interface modifier. Other components and preparation methods are completely consistent with those in Example 1.

[0046] The isocyanate-terminated polyether polyols used in the embodiments and comparative examples of this invention were prepared by the following method: Under nitrogen protection, 100 parts of dried polytetramethylene ether diol (number average molecular weight 1750) and 32.5 parts of toluene diisocyanate were added to 250 parts of dried toluene, stirred and heated to 75°C, and 0.2 parts of dibutyltin dilaurate were added. The mixture was stirred and reacted at this temperature for 2.5 h. After the reaction was completed, the toluene was removed by vacuum distillation to obtain the isocyanate-terminated polyether polyol.

[0047] The components of the embodiments and comparative examples of the present invention are mixed according to the specified ratio, stirred and dispersed evenly, and after standing to remove bubbles, they are coated onto the surface of a sandblasted carbon steel test plate. The coating is then heated and cured at 120°C for 30 minutes to obtain an anti-corrosion coating film with a dry film thickness of 40μm to 50μm.

[0048] Performance testing: The coated films obtained in Examples 1-5 and Comparative Examples 1-3 were subjected to the following relevant performance tests, and the test results are shown in Table 1: (1) Salt spray resistance test: According to GB / T 10125-2021 standard, the test plate coated with the anti-corrosion coating film was placed in the salt spray chamber at an angle of 20°±5° to the vertical direction. A sodium chloride solution with a concentration of 50g / L±5g / L was continuously sprayed at 35℃±2℃. The time when the coating surface first showed blistering, rusting or peeling was taken as the result of salt spray resistance. (2) Adhesion test: Referring to GB / T 9286-2021 standard, a multi-blade cutting tool with 6 blades and a blade spacing of 2mm was used to cut orthogonal grid scratches on the test plate coated with the anti-corrosion coating film. After applying pressure-sensitive adhesive tape, the coating was peeled off smoothly at a 60° angle within 0.5s to 1.0s. The adhesion level was evaluated based on the proportion of the area of ​​the coating peeled off from the substrate. (3) Impact resistance test: Referring to GB / T 1732-2020 standard, the test plate coated with the anti-corrosion adhesive film was placed flat on an anvil with the coating facing upward. An impactor with a weight of 1000g was used to drop the weight freely from different heights to impact the test plate. The maximum impact height at which the coating did not crack or peel off was taken as the impact resistance result.

[0049] Table 1

[0050] As can be seen from the test results in Table 1, this invention significantly improves the salt spray resistance, adhesion, and impact resistance of the trifluorochloroethylene copolymer anti-corrosion coating film by using modified functional fillers and modified interface modifiers in synergistic effect. Comparative Example 1 uses unmodified glass flakes instead of the modified functional filler. The filler surface lacks chemical grafting of polyether segments, resulting in poor compatibility with the resin matrix. Numerous micropores exist at the filler-resin interface within the coating, allowing corrosive media to penetrate rapidly along the interface, significantly weakening the shielding function. Furthermore, the unmodified filler becomes a stress concentration point under impact, leading to a decrease in coating toughness. Because its interface modifier was not replaced, it retains the chemical bonding function of the silane end groups, thus its adhesion remains unaffected. Comparative Example 2 uses unmodified silane coupling agents instead of the modified interface modifier. These agents only provide interfacial bonding for the silane end groups, lacking the active corrosion inhibition function and interface densification effect provided by the Schiff base-zinc ion chelate structure. After the corrosive media penetrates to the substrate interface, it cannot form passivation protection, and the adhesion decreases due to insufficient interface layer densification. Comparative Example 3, employing both unmodified fillers and unmodified interface modifiers, exhibited a coexistence of shielding failure and corrosion inhibition. Corrosive media rapidly reached the substrate along the filler interface defects without effective suppression, with the two defects mutually exacerbating each other, resulting in the most severe overall performance deterioration. This demonstrates that the present invention, by combining two modified substances, constructs a dense shielding network within the coating body and a multifunctional protective layer at the substrate interface, achieving a dual long-term anti-corrosion effect of passive shielding and active corrosion inhibition.

[0051] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0052] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A trifluorochloroethylene copolymer anti-corrosion coating film, characterized in that, The raw materials include the following parts by weight: 90-110 parts trifluorochloroethylene copolymer, 15-25 parts epoxy resin, 8-15 parts crosslinking agent, 0.2-0.8 parts curing accelerator, 15-35 parts modified functional filler, 3-6 parts modified interface modifier, 0.8-1.5 parts leveling agent, and 80-100 parts xylene; The modified functional filler is prepared by the following steps: A1. Add 80-120 parts of glass flakes and 10-12 parts of γ-aminopropyltriethoxysilane to a mixed solvent of anhydrous ethanol and deionized water, adjust the pH of the system to 4.5-5.5 with acetic acid, heat the reaction, filter, wash, and vacuum dry after the reaction to obtain silanized activated filler. A2. Under nitrogen protection, 90-110 parts of the silanized activated filler obtained in step A1 and 30-35 parts of isocyanate-terminated polyether polyol are added to 350-450 parts of dry toluene, and 0.5-1.5 parts of dibutyltin dilaurate are added. The mixture is heated to react, and after the reaction is completed, it is filtered, washed, and vacuum dried to obtain the modified functional filler. The modified interface modifier is prepared by the following steps: B1. Dissolve 90-110 parts of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in tetrahydrofuran, add 28-32 parts of tetrahydrofuran solution of terephthalaldehyde dropwise under nitrogen protection, stir the reaction, and distill under reduced pressure after the reaction is completed to obtain Schiff alkalized prepolymer. B2. Dissolve 90-110 parts of the Schiff alkalized prepolymer obtained in step B1 in ethanol, add 6-8 parts of aniline, stir well, add 13-17 parts of zinc nitrate ethanol solution dropwise, adjust the pH to 4.2-4.8 with nitric acid, heat the reaction, distill under reduced pressure after the reaction is completed, and dry under vacuum to obtain the modified interface modifier.

2. The trifluorochloroethylene copolymer anti-corrosion coating film according to claim 1, characterized in that, In step A1, the volume ratio of anhydrous ethanol to deionized water in the mixed solvent is (8-10):1, the heating reaction temperature is 50-60℃, the time is 2-3h, and the vacuum drying temperature is 80-100℃.

3. The trifluorochloroethylene copolymer anti-corrosion coating film according to claim 1, characterized in that, In step A2, the heating reaction is carried out at a temperature of 65-75°C for 3-4 hours, and the vacuum drying is carried out at a temperature of 65-75°C.

4. The trifluorochloroethylene copolymer anti-corrosion coating film according to claim 1, characterized in that, In step B1, the stirring reaction is carried out at a temperature of 28-32°C for 2-3 hours, and the mass fraction of terephthalaldehyde in the tetrahydrofuran solution is 15%-25%.

5. The trifluorochloroethylene copolymer anti-corrosion coating film according to claim 1, characterized in that, In step B2, the heating reaction is carried out at a temperature of 50-55°C for 4-5 hours, the vacuum drying is carried out at a temperature of 42-48°C, and the zinc nitrate in the ethanol solution is 20%-35% by mass.

6. The trifluorochloroethylene copolymer anti-corrosion coating film according to claim 1, characterized in that, The trifluorochloroethylene copolymer is trifluorochloroethylene-vinyl ester copolymer Lumiflon LF-200.

7. The trifluorochloroethylene copolymer anti-corrosion coating film according to claim 1, characterized in that, The epoxy resin is bisphenol A type epoxy resin E-44.

8. The trifluorochloroethylene copolymer anti-corrosion coating film according to claim 1, characterized in that, The crosslinking agent is methylated melamine-formaldehyde resin Cymel 303.

9. The trifluorochloroethylene copolymer anti-corrosion coating film according to claim 1, characterized in that, The curing accelerator is p-toluenesulfonic acid monohydrate.

10. The trifluorochloroethylene copolymer anti-corrosion coating film according to claim 1, characterized in that, The leveling agent is a polyether-modified silicone leveling agent, BYK-331.

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