Organosilicon modified epoxy self-repairing anticorrosive paint as well as preparation method and application thereof

Abstract

According to the organic silicon modified epoxy self-repairing anti-corrosion coating and the preparation method and application thereof, amino functionalized graphene, nano silicon dioxide and self-repairing microcapsules (dicyclopentadiene) are added into a coating formula in a chemical modification mode, the molecular structure of epoxy resin (bisphenol A type) is optimized, and the self-repairing anti-corrosion coating is prepared. On the basis of enhancing the physical and mechanical properties of the coating, better physical and mechanical properties, corrosion resistance, heat resistance and self-repairing functions of the coating are further realized. The coating can meet protection of parts with high corrosion resistance, high application environment temperature and abrasion and damage problems, is specifically applied to the fields of high-temperature pipeline protection, corrosion resistance of lithium battery shells, engine blades, photovoltaic supports and the like, and can prolong the service life of related parts and equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of anti-corrosion coatings, and specifically relates to an organosilicon-modified epoxy self-repairing anti-corrosion coating and a preparation method and application thereof. Background Art

[0002] Through appropriate coating processes, the paint is applied to the substrate surface and cured to form a continuous coating with specific physical and mechanical properties. This coating isolates the substrate from the external corrosive environment, providing a physical barrier to corrosion. Paints containing anti-rust pigments can also provide electrochemical corrosion protection after the coating is formed, further strengthening the protection of the substrate. In the modern coatings industry, polymer synthetic resins, with their excellent physical and chemical properties, are gradually replacing traditional vegetable oils and are widely used as film-forming materials and binders in coatings.

[0003] Among various polymer synthetic resins, epoxy resin (EP) possesses excellent adhesion, good mechanical properties, and good corrosion and chemical resistance. Silicone resin, as the primary film-forming substance in coatings, combines excellent flexibility, high and low temperature resistance, and weather resistance. However, epoxy resin has poor heat resistance, a high crosslinking density after curing, and a three-dimensional network structure. This leads to high internal stress, brittleness, and poor impact resistance. Silicone resin, on the other hand, suffers from poor mechanical and solvent resistance. Both resins have their own advantages and disadvantages, and through chemical modification, their strengths can be leveraged to overcome their weaknesses, resulting in a silicone-modified epoxy resin with excellent overall performance.

[0004] Current research reports on organosilicon-modified epoxy resins mainly focus on improving their physical and chemical properties as film-forming materials for coatings. Chinese patent CN109897503A discloses a room-temperature curing organosilicon-modified epoxy resin coating, its preparation method, and application. This coating focuses on improving the curing temperature of the film-forming material through chemical modification, while also improving the physical and mechanical properties and light transmittance of the coating. Chinese patent CN119286363A discloses an anti-corrosion coating with self-repairing function. This coating focuses on achieving coating damage warning and repair functions, and mainly relies on the physical shielding effect of the coating (i.e., isolating the substrate from the external corrosive environment) to achieve the purpose of corrosion protection. Chinese patent CN102101964A discloses an organosilicon-modified epoxy heat-resistant anti-corrosion coating. Through the condensation reaction of hydroxyl, amino, and alkoxy groups in the organosilicon resin with hydroxyl groups in the epoxy resin, the organosilicon-Si-O- group is grafted onto the epoxy resin to obtain a coating with good heat resistance and corrosion resistance. However, the above-mentioned existing technologies all focus on improving the performance of one aspect of epoxy resin coatings, and fail to organically integrate "sacrificial anode" protection, physical shielding protection, coating self-repair and high temperature resistance to achieve a comprehensive improvement in the physical and mechanical properties and functionality of the coating. Summary of the Invention

[0005] (1) Technical issues to be resolved

[0006] The present invention proposes an organosilicon-modified epoxy self-healing anti-corrosion coating and its preparation method and application, in order to solve the technical problem of how to prepare an epoxy resin modified coating with excellent physical and mechanical properties and self-healing properties.

[0007] (2) Technical solution

[0008] In order to solve the above technical problems, the present invention proposes a silicone-modified epoxy self-healing anti-corrosion coating, in which the film-forming substance is a silicone-modified epoxy resin, the pigments are titanium dioxide and zinc phosphate, the fillers are mica powder, nano-silica and amino-functionalized graphene, the additives are dicyclopentadiene microcapsules, silane coupling agents, polyether-modified silicone defoaming agents and fluorine-modified acrylic leveling agents, and the solvents are propylene glycol methyl ether acetate and xylene.

[0009] Furthermore, by mass ratio, the silicone-modified epoxy resin is 48-52%; the rutile titanium dioxide is 8-10%, the zinc phosphate is 5-6%; the mica powder is 6-8%, the nano-silica is 2-3%, the amino-functionalized graphene is 1.5-2.5%; the dicyclopentadiene microcapsules are 3-4%, the silane coupling agent is 1-1.5%, the polyether-modified silicone defoaming agent is 0.3-0.5%, the fluorine-modified acrylic leveling agent is 0.1-0.3%; and propylene glycol methyl ether acetate and xylene are the balance.

[0010] Furthermore, the titanium dioxide is rutile titanium dioxide, the silane coupling agent is KH-560, the polyether modified siloxane defoaming agent is BYK-052, and the fluorine modified acrylic leveling agent is BYK-333.

[0011] In addition, the present invention also provides a method for preparing an organosilicon-modified epoxy self-repairing anti-corrosion coating, which comprises the following steps:

[0012] S1. Synthesis of silicone-modified epoxy resin

[0013] S1-1. Prepare bisphenol A epoxy resin and trimethylsilanol;

[0014] S1-2 bisphenol A epoxy resin and xylene were added to the reactor and vacuum dehydrated;

[0015] S1-3 under nitrogen, trimethylsilanol was added to the solution in the reactor and stirred, and stirring was continued after completion of the addition to thoroughly mix the bisphenol A epoxy resin and trimethylsilanol;

[0016] S1-4. Raise the reaction temperature, add an acidic catalyst to the solution in the reactor, and stir uniformly during the reaction; under the action of acidic catalysis, the oxygen atoms in the epoxy groups of bisphenol A epoxy resin are protonated, the electrophilicity increases, and the epoxy groups are ring-opened and condensed with the hydroxyl groups in trimethylsilanol;

[0017] S1-5 cooling, decompression, distillation, until the system no fraction distilled out to obtain a light yellow viscous liquid, that is, to achieve the preparation of silicone-modified epoxy resin;

[0018] S2. Preparation of dicyclopentadiene self-healing microcapsules

[0019] S2-1. Prepare dicyclopentadiene, urea, formaldehyde solution and emulsifier;

[0020] S2-2 was added to a three-necked flask formaldehyde solution and urea, and start stirring; the three-necked flask was placed in an oil bath, the reaction system was adjusted to a pH value of 8.0 to 8.5, and the reaction temperature was maintained at 70 ° C. Under alkaline conditions, urea and formaldehyde undergo a step-by-step nucleophilic addition reaction to produce monomethylol urea and dimethylol urea; the reaction system was adjusted to a pH value of 4 to 5, the reaction was continued at 70 ° C, stirring was maintained during the reaction, -NH-CH2OH as an active intermediate linear polymer compound was further polycondensed to obtain a light yellow or colorless urea-formaldehyde resin prepolymer;

[0021] S2-3 The prepared urea-formaldehyde prepolymer was added to a three-necked flask containing toluene and stirred to disperse the solution evenly; an emulsifier was added and stirred continuously to fully dissolve and disperse the emulsifier; increasing the stirring speed, dicyclopentadiene was added to the solution system, and after addition, stirring was continued to form a stable emulsion system;

[0022] S2-4 slowly heated to 45 ° C, adjusted the reaction system pH value to 7 to 8; maintaining temperature and pH conditions, the reaction time ≥ 3h, the polyurea resin prepolymer polymerization reaction occurs on the surface of the dicyclopentadiene droplets to form a microcapsule wall;

[0023] S2-5 After the reaction, the system was cooled to room temperature, the reaction solution was transferred to a centrifuge tube and centrifuged to separate the microcapsules; the upper clear night was poured out, the bottom microcapsule precipitate was collected, the microcapsules were washed several times with toluene, and the centrifugation process was repeated to remove unreacted impurities; the collected microcapsules were moved to a vacuum drying oven and dried to obtain dicyclopentadiene self-repairing microcapsules;

[0024] S3. Preparation of amino-functionalized graphene

[0025] S3-1. Graphene oxide was added to deionized water and ultrasonically cleaned to uniformly disperse the graphene oxide to obtain a brown suspension; allowed to stand to remove undispersed matter; and the suspension was adjusted to a pH value of 8 to 9 to enhance the activity of the functional groups of graphene oxide.

[0026] S3-2. Under nitrogen, ethylenediamine was added to the above suspension, heated with stirring, and reacted; hydrazine hydrate was added, and the temperature was continued to rise, and the reaction;

[0027] S3-3. After the reaction is completed, the reaction mixture is cooled to room temperature, and the reaction mixture is transferred to a centrifuge tube and centrifuged to separate the solid product; the solid product is washed alternately with N,N-dimethylformamide and deionized water to remove unreacted impurities and by-products; the collected solid product is moved to a vacuum drying oven for drying to obtain dark brown to black powdered amino-functionalized graphene;

[0028] S4. Preparation of silicone-modified epoxy self-healing anti-corrosion coating

[0029] S4-1 titanium dioxide, zinc phosphate, mica powder, nano-silica, amino-functionalized graphene was added to propylene glycol methyl ether acetate and xylene solvent for pre-dispersion;

[0030] S4-2. The pre-dispersed pigments, fillers, and dicyclopentadiene self-healing microcapsules are added to the silicone-modified epoxy resin and stirred to ensure that the liquid is fully mixed and the microcapsules are not broken;

[0031] S4-3. Add a silane coupling agent to the silicone-modified epoxy resin, increase the speed, and continue stirring; add a polyether-modified silicone defoamer and continue stirring; add a fluorine-modified acrylic leveling agent and continue stirring; add propylene glycol methyl ether acetate and xylene to adjust the coating viscosity;

[0032] S4-4. Filter the coating obtained in step S4-3 to remove undispersed particles and impurities to prepare an organosilicon-modified epoxy self-healing anti-corrosion coating.

[0033] Furthermore, in step S1-1, the molar ratio is based on epoxy group: trimethylsilanol = 1:1.5; in step S1-2, vacuum dehydration is carried out at 60-65°C for 2h; in step S1-3, the temperature of the solution system is increased by ≤10°C by controlling the addition rate of trimethylsilanol; in step S1-4, the reaction temperature is increased to 100-110°C, the reaction is carried out for 3-6h, and the epoxy value is detected to drop to 40-45% of the initial state; in step S1-5, the pressure is controlled at 0.01-0.1MPa.

[0034] Furthermore, in step S2-2, the emulsifiers are sodium dodecylbenzenesulfonate and Span-80; and in step S2-4, the heating rate is 1-2°C / min.

[0035] Furthermore, in step S3-2, after adding ethylenediamine, the temperature was raised to 80° C. with stirring and the reaction was carried out for 1 hour; hydrazine hydrate was added, the temperature was slowly raised to 100° C., and the reaction was carried out for 2 hours; in step 3-3, the mixture was dried at 60° C. for 12 hours.

[0036] Furthermore, in step S4-1, a disperser is used to pre-disperse at 1000-2000 rpm for 20-30 minutes; in step S4-2, stirring is performed at a speed of 200-300 rpm for 5-10 minutes; in step S4-3, a silane coupling agent is added, the speed is increased to 500-800 rpm, and stirring is continued for 15-30 minutes; a polyether-modified silicone defoamer is added, and stirring is continued for 10-15 minutes; a fluorine-modified acrylic leveling agent is added, and stirring is continued for 10-15 minutes; propylene glycol methyl ether acetate and xylene are added, and the viscosity of the coating is adjusted to 30-60 seconds.

[0037] In addition, the present invention also proposes an application of the above-mentioned organosilicon-modified epoxy self-repairing anti-corrosion coating.

[0038] Furthermore, a curing agent is added to the organosilicon-modified epoxy self-repairing anti-corrosion coating, stirred evenly, and after aging, sprayed using an air spray gun and cured.

[0039] (3) Beneficial effects

[0040] The present invention proposes a silicone-modified epoxy self-healing anti-corrosion coating, its preparation method, and application. By chemically modifying the coating formula, amino-functionalized graphene, nano-silica, and self-healing microcapsules (dicyclopentadiene) are added to the coating formula to optimize the molecular structure of the epoxy resin (bisphenol A type). This enhances the physical and mechanical properties of the coating while further achieving better physical and mechanical properties, corrosion resistance, heat resistance, and self-healing properties. The present invention can meet the requirements of protecting parts with strong corrosion resistance, high ambient temperatures, and those facing wear and breakage. Specific applications include high-temperature pipeline protection, lithium battery housings, engine blades, and photovoltaic bracket corrosion protection, and can extend the service life of related parts and equipment. DETAILED DESCRIPTION

[0041] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below with reference to the embodiments.

[0042] This embodiment provides a method for preparing a silicone-modified epoxy self-repairing anti-corrosion coating, which specifically includes the following steps:

[0043] S1. Synthesis of silicone-modified epoxy resin

[0044] S1-1. Prepare bisphenol A epoxy resin (E-51) and trimethylsilanol according to the epoxy group: trimethylsilanol (molar ratio) = 1:1.5. Based on the epoxy equivalent weight of E-51 of 185g / eq, prepare 362g of trimethylsilanol (purity ≥99%) for every 500g of E-51.

[0045] S1-2. Add bisphenol A epoxy resin and 40g of xylene (dehydration solvent) into a reactor and dehydrate under vacuum (-0.095MPa) at 60-65°C for 2h until the solvent moisture content is ≤0.03% (Karl Fischer method).

[0046] S1-3. Under nitrogen protection, slowly add (preferably within 30 minutes) a weighed amount of trimethylsilanol to the solution in the reactor and stir (300-500 rpm). By controlling the addition rate of trimethylsilanol, the temperature of the solution system is raised by ≤10°C. After the addition is completed, continue stirring to fully mix the bisphenol A epoxy resin and trimethylsilanol.

[0047] S1-4. The reaction temperature was raised to 100-110°C, and 1.0 g of p-toluenesulfonic acid (PTSA) catalyst was slowly added to the solution in the reactor (preferably within 5-10 min). The reaction was stirred at a constant speed to ensure that the proton H + Evenly transfer; react for 3 to 6 hours, and the epoxy value is detected to drop to 40 to 45% of the initial state (determined by hydrochloric acid acetone method).

[0048] S1-5. Cool to 60°C, reduce pressure, and distill to remove small molecular by-products (such as methanol and water) in the system. The pressure is controlled at 0.01-0.1 MPa until no fraction is distilled out of the system; a light yellow viscous liquid is obtained (at 25°C, the liquid viscosity is 4500-5000 mPa·s, and the Si content is 8.5-9.2%).

[0049] In this step, the oxygen atoms in the epoxy groups of the bisphenol A epoxy resin (E-51) are protonated under the catalytic action of an acid (at least one of dibutyltin dilaurate and PTSA p-toluenesulfonic acid), increasing their electrophilicity. The epoxy groups then ring-open and undergo a condensation reaction with the hydroxyl groups in trimethylsilanol, thereby preparing a silicone-modified epoxy resin.

[0050] For ease of representation, the -CH3 group appearing in the chemical formula is replaced by R:

[0051]

[0052] The chemical reaction formula is as follows:

[0053]

[0054] After the reaction, one of the epoxy groups in the bisphenol A epoxy resin is replaced by a trimethylsilyloxy group (-O-Si(CH3)3), while the epoxy group at the other end remains, maintaining crosslinking and curing capabilities. Because the Si-O bond energy (452 ​​kJ / mol) is greater than the C-C bond (347 kJ / mol), the modified silicone resin exhibits a certain degree of improved stability compared to the original epoxy resin.

[0055] S2. Preparation of dicyclopentadiene self-healing microcapsules

[0056] S2-1. Add dicyclopentadiene self-healing microcapsules at 5% (mass ratio), then prepare about 18.0g of dicyclopentadiene (purity ≥99.7%), about 20.0g of urea (purity ≥99.7%), about 39.0g of 37% formaldehyde solution, about 0.5g of sodium dodecylbenzenesulfonate (SDBS, purity ≥99.5%), and about 0.5g of Span-80 (purity ≥99.5%).

[0057] S2-2. Using a three-necked flask equipped with a stirrer, reflux condenser, and thermometer, add the weighed formaldehyde solution and urea and stir at 200-300 rpm. Place the flask in an oil bath and add 2.5 mol / L sodium hydroxide solution dropwise to adjust the pH of the reaction system to 8.0-8.5. Maintain the reaction temperature at 70°C.

[0058] Under alkaline conditions, urea and formaldehyde undergo a stepwise nucleophilic addition reaction to produce monomethylol urea and dimethylol urea. The chemical equation for the above reaction is as follows:

[0059] ①

[0060]

[0061] The pH of the reaction system is adjusted to 4-5 using 2 mol / L hydrochloric acid. The reaction is then allowed to proceed at this temperature for 45 minutes while stirring to ensure complete reaction. Under acidic conditions, the linear polymer compound with (-NH-CH2OH) as the active intermediate undergoes further polycondensation, ultimately yielding a light yellow or colorless urea-formaldehyde resin prepolymer with a desired viscosity.

[0062] S2-3. Add the prepared urea-formaldehyde resin prepolymer into a three-necked flask containing 50 ml of toluene (43.3 g) (room temperature) and start stirring to disperse the solution evenly; add weighed sodium dodecylbenzenesulfonate (SDBS) and Span-80, and continue stirring for 10 minutes to allow the emulsifier (i.e., sodium dodecylbenzenesulfonate and Span-80) to be fully dissolved and dispersed; increase the stirring speed to 1500 rpm, and slowly add dicyclopentadiene (3 ml / min, about 2.94 g / min) to the solution system. After the addition is complete, continue stirring for 15 minutes to form a stable emulsion system.

[0063] S2-4. Slowly raise the temperature to 45°C (heating rate of 1-2°C / min) and adjust the pH value of the reaction system to 7-8 using 2 mol / L sodium hydroxide solution; maintain the temperature and pH conditions for a reaction time of ≥3h to allow the polyurea resin prepolymer to polymerize on the surface of the dicyclopentadiene droplets to form the microcapsule wall.

[0064] S2-5. After the reaction is completed, the system is cooled to room temperature, the reaction solution is transferred to a centrifuge tube and centrifuged for 15 minutes (speed 4000 rpm) to separate the microcapsules; the upper clear night is poured out, the microcapsule precipitate at the bottom is collected, and the microcapsules are washed multiple times (≥3 times) with toluene, and the centrifugation process is repeated to remove unreacted impurities; the collected microcapsules are transferred to a vacuum drying oven and dried at 50°C for 20 hours to obtain dicyclopentadiene self-healing microcapsules.

[0065] S3. Preparation of amino-functionalized graphene

[0066] S3-1. Add 10.0 g of graphene oxide (GO) to 500 ml of deionized water and use ultrasonic cleaning (40 kHz) for 30 min to evenly disperse the GO to obtain a brown suspension; let it stand for 10 min to remove undispersed matter; use 0.1 mol / L sodium hydroxide solution to adjust the pH value of the suspension to 8-9 to enhance the activity of the GO functional groups.

[0067] S3-2. Under nitrogen protection, 0.1 g of ethylenediamine (purity ≥99.7%) was added to the above suspension, and the temperature was raised to 80°C while slowly stirring (200-300 rpm), and the reaction was carried out for 1 hour; 53.75 g of hydrazine hydrate (80% concentration) was added, the temperature was slowly raised to 100°C, and the reaction was carried out for 2 hours.

[0068] S3-3. After the reaction is completed, cool to room temperature, transfer the reaction mixture to a centrifuge tube and centrifuge for 10 minutes (5000 rpm) to separate the solid product; use N,N-dimethylformamide (DMF, purity ≥99.7%) and deionized water to alternately wash the solid product to remove unreacted impurities and by-products; transfer the collected solid product to a vacuum drying oven and dry it at 60°C for 12 hours to obtain dark brown to black powdered amino-functionalized graphene.

[0069] In this step, graphene oxide (GO) reacts with ethylenediamine under the catalysis of hydrogen peroxide to generate GO-NH2. The chemical reaction formula is as follows:

[0070]

[0071] S4. Preparation of silicone-modified epoxy self-healing anti-corrosion coating

[0072] S4-1. Add pigments and fillers such as titanium dioxide, zinc phosphate, mica powder (325 mesh), nano-silica, and amino-functionalized graphene to a small amount of propylene glycol methyl ether acetate (PMA) and xylene solvent, and pre-disperse them at 1000-2000 rpm using a disperser for 20-30 minutes.

[0073] S4-2. Add the pre-dispersed pigments, fillers and dicyclopentadiene self-healing microcapsules to the silicone-modified epoxy resin and stir at 200-300 rpm for 5-10 minutes to ensure that the liquid is fully mixed and the microcapsules are not broken.

[0074] S4-3. Continue adding silane coupling agent (KH-560) to the silicone-modified epoxy resin, increase the speed to 500-800 rpm, and continue stirring for 15-30 minutes. Add polyether-modified silicone defoamer (BYK-052) and continue stirring for 10-15 minutes. Add fluorinated acrylic leveling agent (BYK-333) and continue stirring for 10-15 minutes. Add appropriate amounts of propylene glycol methyl ether acetate (PMA) and xylene to adjust the coating viscosity, generally to 30-60 seconds (applying 4 cups).

[0075] S4-4. Use a filtration device with a filter mesh size of 100 to 300 to filter the coating obtained in step S4-3 in order according to the fineness to remove undispersed particles, impurities, etc., and control the filtration pressure at 0.1 to 0.3 MPa; prepare a silicone-modified epoxy self-healing anti-corrosion coating.

[0076] By mass ratio, the silicone-modified epoxy self-healing anti-corrosion coating contains 48-52% silicone-modified epoxy resin; 8-10% rutile titanium dioxide; 5-6% zinc phosphate; 6-8% mica powder; 2-3% nano-silica; 1.5-2.5% amino-functionalized graphene; 3-4% dicyclopentadiene microcapsules; 1-1.5% silane coupling agent; 0.3-0.5% polyether-modified silicone defoaming agent; 0.1-0.3% fluorine-modified acrylic leveling agent; and the balance is propylene glycol methyl ether acetate and xylene.

[0077] In this step, dicyclopentadiene undergoes ring-opening metathesis polymerization under the action of Grubbs catalyst to form a three-dimensional network structure. The chemical reaction formula is as follows:

[0078]

[0079] When the coating cracks or is damaged, the dicyclopentadiene self-repairing capsules uniformly dispersed and solidified in the coating rupture under the influence of the stress at the crack propagation tip. The released monomers polymerize under the action of Grubbs catalyst to form a network structure, filling the cracked and damaged coating, thereby achieving self-repair of the coating.

[0080] Coating preparation: Before construction (painting), add curing agent (mixture of methylhexahydrophthalic anhydride MHHPA and 2-ethyl-4-methylimidazole, ratio of 20:1) in a mass ratio of 5:1, stir thoroughly, and mature for 15 minutes before use; use an air spray gun, air pressure 0.4~0.6MPa, spray gun diameter 1.5~2.0mm, spray speed 30~60cm / s, construction viscosity adjusted to 20~30s (coating-4 cups), coating thickness 80~120μm, curing temperature 120℃, curing time 2h, and the applicable period of the paint after mixing is 6h (4h in summer).

[0081] The coating prepared based on the present invention forms a coating with excellent physical and mechanical properties, anti-corrosion and rust prevention, heat resistance and self-repairing properties after coating and curing. The anti-rust pigment added to the coating is zinc phosphate Zn3(PO4)2, which can form a Zn3(PO4)2·4H2O passivation layer on the metal surface after coating, isolating the external corrosive environment from the contact with the substrate, reducing the electrochemical activity of the surface layer, and slowing down the corrosion reaction; at the same time, the amino-functionalized graphene and nano-silicon dioxide added to the coating enhance the maze effect, prolonging the distance for external corrosive factors to reach the metal substrate, thereby enhancing the anti-corrosion performance of the coating. The presence of densely stacked lamellar graphene in the coating can not only hinder the expansion of cracks in the coating, but also play an excellent stress absorption role, which can improve the heat dissipation capacity of the coating (graphene thermal conductivity is 5300W / m·K), and improve the strength and heat resistance of the coating. The presence of rigid epoxy segments and flexible silicone segments in the silicone-modified epoxy resin improves the strength and toughness of the coating. The properties of the prepared coating after coating and drying and curing are shown in Table 1 below.

[0082] Table 1 Self-repairing and anti-corrosion properties of silicone-modified epoxy

[0083] Adhesion flexibility Impact resistance Heat resistance Salt spray resistance ≤Level 0 1mm 50kg·cm 240℃ / 200h, no change in appearance 1000h, no blistering, no rust

[0084] Note: The performance tests mentioned above are carried out in accordance with the following standards: GB / T 1720 Determination of adhesion of paint films; GB / T 1732 Determination of impact resistance of paint films; GB / T 1731 Determination of flexibility of paint films; GB / T 1735 Paints and varnishes - Determination of heat resistance; GB / T 1771 Paints and varnishes - Determination of resistance to neutral salt spray.

[0085] Application scenarios: The coating has excellent corrosion resistance, high temperature resistance and physical and mechanical properties. It can be used in high-temperature pipeline protection, lithium battery housings, engine blades, photovoltaic bracket anti-corrosion and other fields to improve the service life of related parts and equipment.

[0086] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A silicone modified epoxy self-repairing anti-corrosion coating, characterized in that: In the organosilicon-modified epoxy self-healing anti-corrosion coating, the film-forming substance is organosilicon-modified epoxy resin, the pigments are titanium dioxide and zinc phosphate, the fillers are mica powder, nano-silica and amino-functionalized graphene, the additives are dicyclopentadiene microcapsules, silane coupling agents, polyether-modified silicone defoamers and fluorine-modified acrylic leveling agents, and the solvents are propylene glycol methyl ether acetate and xylene.

2. The organosilicon-modified epoxy self-repairing anti-corrosion coating according to claim 1, characterized in that: By mass ratio, the silicone-modified epoxy resin is 48-52%; the rutile titanium dioxide is 8-10%, the zinc phosphate is 5-6%; the mica powder is 6-8%, the nano-silica is 2-3%, the amino-functionalized graphene is 1.5-2.5%; the dicyclopentadiene microcapsule is 3-4%, the silane coupling agent is 1-1.5%, the polyether-modified silicone defoaming agent is 0.3-0.5%, and the fluorine-modified acrylic leveling agent is 0.1-0.3%; and the balance is propylene glycol methyl ether acetate and xylene.

3. The organosilicon-modified epoxy self-repairing anti-corrosion coating according to claim 1, characterized in that: The titanium dioxide used is rutile titanium dioxide, the silane coupling agent is KH-560, the polyether modified siloxane defoaming agent is BYK-052, and the fluorine-modified acrylic leveling agent is BYK-333.

4. A method for preparing the organosilicon-modified epoxy self-repairing anti-corrosion coating according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: S1. Synthesis of silicone-modified epoxy resin S1-1. Prepare bisphenol A epoxy resin and trimethylsilanol; S1-2 bisphenol A epoxy resin and xylene were added to the reactor and vacuum dehydrated; S1-3 under nitrogen, trimethylsilanol was added to the solution in the reactor and stirred, and stirring was continued after completion of the addition to thoroughly mix the bisphenol A epoxy resin and trimethylsilanol; S1-4. Raise the reaction temperature, add an acidic catalyst to the solution in the reactor, and stir uniformly during the reaction; under the action of acidic catalysis, the oxygen atoms in the epoxy groups of bisphenol A epoxy resin are protonated, the electrophilicity increases, and the epoxy groups are ring-opened and condensed with the hydroxyl groups in trimethylsilanol; S1-5 cooling, decompression, distillation, until the system no fraction distilled out to obtain a light yellow viscous liquid, that is, to achieve the preparation of silicone-modified epoxy resin; S2. Preparation of dicyclopentadiene self-healing microcapsules S2-1. Prepare dicyclopentadiene, urea, formaldehyde solution and emulsifier; S2-2 was added to a three-necked flask formaldehyde solution and urea, and start stirring; the three-necked flask was placed in an oil bath, the reaction system was adjusted to a pH value of 8.0 to 8.5, and the reaction temperature was maintained at 70 ° C. Under alkaline conditions, urea and formaldehyde undergo a step-by-step nucleophilic addition reaction to produce monomethylol urea and dimethylol urea; the reaction system was adjusted to a pH value of 4 to 5, the reaction was continued at 70 ° C, stirring was maintained during the reaction, -NH-CH2OH as an active intermediate linear polymer compound was further polycondensed to obtain a light yellow or colorless urea-formaldehyde resin prepolymer; S2-3 The prepared urea-formaldehyde prepolymer was added to a three-necked flask containing toluene and stirred to disperse the solution evenly; Add emulsifier and continue stirring to fully dissolve and disperse the emulsifier; Increase the stirring speed and add dicyclopentadiene to the solution system. After the addition is complete, continue stirring to form a stable emulsion system. S2-4 slowly heated to 45 ° C, adjusted the reaction system pH value to 7 to 8; maintaining temperature and pH conditions, the reaction time ≥ 3h, the polyurea resin prepolymer polymerization reaction occurs on the surface of the dicyclopentadiene droplets to form a microcapsule wall; S2-5 After the reaction, the system was cooled to room temperature, the reaction solution was transferred to a centrifuge tube and centrifuged to separate the microcapsules; the upper clear night was poured out, the bottom microcapsule precipitate was collected, the microcapsules were washed several times with toluene, and the centrifugation process was repeated to remove unreacted impurities; The collected microcapsules were moved to a vacuum drying oven and dried to obtain dicyclopentadiene self-repairing microcapsules; S3. Preparation of amino-functionalized graphene S3-1. Graphene oxide was added to deionized water and ultrasonically cleaned to uniformly disperse the graphene oxide to obtain a brown suspension; allowed to stand to remove undispersed matter; and the suspension was adjusted to a pH value of 8 to 9 to enhance the activity of the functional groups of graphene oxide. S3-2. Under nitrogen, ethylenediamine was added to the above suspension, heated with stirring, and reacted; hydrazine hydrate was added, and the temperature was continued to rise, and the reaction; S3-3. After the reaction is completed, the reaction mixture is cooled to room temperature, and the reaction mixture is transferred to a centrifuge tube and centrifuged to separate the solid product; the solid product is washed alternately with N,N-dimethylformamide and deionized water to remove unreacted impurities and by-products; the collected solid product is moved to a vacuum drying oven for drying to obtain dark brown to black powdered amino-functionalized graphene; S4. Preparation of silicone-modified epoxy self-healing anti-corrosion coating S4-1 titanium dioxide, zinc phosphate, mica powder, nano-silica, amino-functionalized graphene was added to propylene glycol methyl ether acetate and xylene solvent for pre-dispersion; S4-2. The pre-dispersed pigments, fillers, and dicyclopentadiene self-healing microcapsules are added to the silicone-modified epoxy resin and stirred to ensure that the liquid is fully mixed and the microcapsules are not broken; S4-3. Add a silane coupling agent to the silicone-modified epoxy resin, increase the speed, and continue stirring; add a polyether-modified silicone defoamer and continue stirring; add a fluorine-modified acrylic leveling agent and continue stirring; add propylene glycol methyl ether acetate and xylene to adjust the coating viscosity; S4-4. Filter the coating obtained in step S4-3 to remove undispersed particles and impurities to prepare an organosilicon-modified epoxy self-healing anti-corrosion coating.

5. The method for preparing the organosilicon-modified epoxy self-repairing anti-corrosion coating according to claim 4, characterized in that: In step S1-1, the molar ratio of epoxy group to trimethylsilanol is 1:1.5; in step S1-2, vacuum dehydration is performed at 60-65° C. for 2 hours; in step S1-3, the temperature of the solution system is increased by ≤10° C. by controlling the addition rate of trimethylsilanol; in step S1-4, the reaction temperature is increased to 100-110° C., the reaction is carried out for 3-6 hours, and the epoxy value is detected to drop to 40-45% of the initial state; in step S1-5, the pressure is controlled at 0.01-0.1 MPa.

6. The method for preparing the organosilicon-modified epoxy self-repairing anti-corrosion coating according to claim 4, wherein: In step S2-2, the emulsifiers are sodium dodecylbenzenesulfonate and Span-80; in step S2-4, the heating rate is 1-2°C / min.

7. The method for preparing the organosilicon-modified epoxy self-repairing anti-corrosion coating according to claim 4, wherein: In step S3-2, after adding ethylenediamine, the temperature was raised to 80°C with stirring and the reaction was carried out for 1 hour; hydrazine hydrate was added, the temperature was slowly raised to 100°C, and the reaction was carried out for 2 hours; in step 3-3, the mixture was dried at 60°C for 12 hours.

8. The method for preparing the organosilicon-modified epoxy self-repairing anti-corrosion coating according to claim 4, wherein: In step S4-1, pre-dispersion is performed at 1000-2000 rpm using a disperser for 20-30 minutes; in step S4-2, stirring is performed at 200-300 rpm for 5-10 minutes; in step S4-3, a silane coupling agent is added, the speed is increased to 500-800 rpm, and stirring is continued for 15-30 minutes; a polyether-modified silicone defoamer is added, and stirring is continued for 10-15 minutes; a fluorine-modified acrylic leveling agent is added, and stirring is continued for 10-15 minutes; propylene glycol methyl ether acetate and xylene are added, and the coating viscosity is adjusted to 30-60 seconds.

9. Use of the organosilicon-modified epoxy self-repairing anti-corrosion coating according to any one of claims 1 to 3.

10. The use of the organosilicon-modified epoxy self-repairing anti-corrosion coating according to claim 9, characterized in that: A curing agent is added to the organosilicon-modified epoxy self-repairing anti-corrosion coating, stirred evenly, and after aging, sprayed using an air spray gun and cured.

Images