Anticorrosive acrylic resin paint and method for preparing the same

Abstract

The present application relates to a kind of side chain modified silica and its preparation method and application, anticorrosive acrylic resin varnish, color paint and its preparation method and application.On the basis of existing amino silane coupling agent, by Michael addition reaction synthesis containing silane coupling agent of carboxyl and amino, and using sol-gel method to prepare corresponding side chain modified silica.The side chain modified silica is used in anticorrosive acrylic resin coating, and the carboxyl and amino in its side chain have good reactivity with the functional groups such as epoxy group, hydroxyl group in organic resin, and after baking and curing, the paint film with higher crosslinking density can be formed, which has good resistance to penetration effect on small molecule hydrocarbons, water molecules or chloride ions, and the paint film after curing has flexibility, impact resistance and weather resistance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coatings, and relates to a side chain modified silicon dioxide, a preparation method and application thereof, and a corrosion-resistant acrylic resin varnish, a color paint and preparation methods and applications thereof. BACKGROUND

[0002] For the protection method of metal corrosion, covering the metal surface with an organic coating is the most cost-effective method to prevent metal corrosion. By coating an organic coating to increase the shielding effect, weather resistance and hardness of the metal surface, the corrosion resistance and physical properties are increased. Not only is the corrosion effect considerable, but also the price is low, so it is widely used.

[0003] Among them, the skin coating of the outer surface of the aircraft is an important material for the structure of the aircraft to prolong the service life of the aircraft and ensure safe flight. The aircraft will encounter high-altitude sudden cooling and sudden heating temperature difference changes and high-speed airflow impact during flight. Therefore, the requirements for aircraft coatings are excellent outdoor weather resistance and corrosion resistance, but there is a common drawback of poor impact resistance of the paint film in low-temperature environments, especially after the flight altitude changes. The phenomenon of temperature drop, the paint film has poor low-temperature impact resistance, and when encountering impurities in the air during flight, fine cracks will be generated, and corrosion will occur at the crack, resulting in failure.

[0004] The current commonly used organic resins for aircraft skin coatings include acrylic resins, polyester resins, polyurethane resins, and fluorocarbon resins. These resins are difficult to meet some key technical indicators of aircraft skin coatings, such as high corrosion resistance, high weather resistance, solvent resistance, impact resistance, and high and low temperature resistance. Therefore, by combining the rigidity and thermal stability of inorganic materials with the flexibility, ductility, and processability of organic resins, the performance of the material is improved, which has become a research hotspot. However, the compatibility of inorganic materials with organic film-forming resins is poor, and the addition cannot effectively improve the crosslinking density of the paint film, resulting in that the corrosion resistance and other properties cannot meet the requirements, and the inorganic material itself needs to be modified to improve the impact resistance, high and low temperature resistance, resistance to different hydrocarbon solvents, salt fog resistance, and weather resistance of the cured coating after being doped with organic resins. SUMMARY

[0005] In view of the defects of the prior art, the technical problem to be solved by the present application is to design and synthesize a silicon dioxide with carboxyl and amino groups on the outside chain, which is used as a crosslinking agent and is used in aircraft coatings together with acrylic resins and epoxy resins. The corrosion-resistant coating after curing has the technical effect of significantly improved impact resistance, high and low temperature resistance, resistance to different hydrocarbon solvents, salt fog resistance, and weather resistance.

[0006] To achieve the above technical purposes, the technical scheme adopted by the present application is as follows:

[0007] In a first aspect, a side chain modified silica is provided, wherein the side chain of the silica comprises 3 to 20 carbon atoms and at least one carboxyl group and one amino group.

[0008] Preferably, the amino group is a secondary amino group.

[0009] Preferably, the side chain of the silica comprises 3 to 12 carbon atoms.

[0010] Preferably, the side chain of the silica has a structure of -CH2CH2CH2NHCH2CH2COOH.

[0011] In a second aspect, a method for preparing the side chain modified silica is provided, comprising: first, using a silane coupling agent containing an amino group to react with acrylic acid or carboxyl acrylate to obtain a modified silane coupling agent, and then using the modified silane coupling agent to react with an organotrialkoxysilane to obtain the side chain modified silica.

[0012] Preferably, the silane coupling agent containing an amino group is selected from any one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, N-aminoethyl-3-aminopropyltrimethoxysilane, or N-aminoethyl-3-aminopropylmethyldimethoxysilane.

[0013] Preferably, the carboxyl acrylate is β-carboxymethyl acrylate.

[0014] Preferably, the organotrialkoxysilane is selected from any one of methyltrimethoxysilane, ethyltrimethoxysilane, or propyltrimethoxysilane.

[0015] Further, in the reactants of the addition reaction, the molar ratio of the silane coupling agent containing an amino group to the acrylic acid or carboxyl acrylate is (0.8-1.0):1.

[0016] Further, the addition reaction uses a polymerization inhibitor to avoid free radical polymerization of the double bond of the acrylic acid or carboxyl acrylate to form an unintended product.

[0017] Preferably, the polymerization inhibitor is selected from any one of hydroquinone, catechol, 2,6-di-tert-butyl-p-cresol, or p-hydroxyanisole.

[0018] More preferably, the polymerization inhibitor is p-hydroxyanisole.

[0019] Preferably, the amount of the polymerization inhibitor is 0.1-1 wt% of the acrylic acid or carboxyl acrylate.

[0020] Further, the temperature of the addition reaction is 60-120°C; preferably, the temperature of the addition reaction is 60-100°C.

[0021] Furthermore, in the reactants of the condensation reaction, the molar ratio of the modified silane coupling agent to the organic ester of orthosilicate is (2-4):1, preferably, the molar ratio of the modified silane coupling agent to the organic ester of orthosilicate is (2-3.5):1.

[0022] Furthermore, the condensation reaction also uses an alcohol solvent and water, wherein the mass ratio of the alcohol solvent to water is (10-20):1; preferably, the alcohol solvent is selected from any one of methanol, ethanol or isopropanol.

[0023] Furthermore, the condensation reaction uses an organic acid to adjust the pH of the reaction system to 3-4; preferably, the organic acid is selected from either formic acid or acetic acid.

[0024] Further, the temperature of the condensation reaction is 50-100℃; preferably, the temperature of the condensation reaction is 50-80℃.

[0025] Furthermore, the condensation reaction uses dibutyltin dilaurate as a catalyst.

[0026] Furthermore, the preparation method of side-chain modified silica also includes: after the condensation reaction is completed, it is left to stand at room temperature for 12-48 hours for aging;

[0027] Furthermore, the preparation method of side-chain modified silica also includes: after aging, vacuum drying at 80-100℃ for 12-48h to obtain side-chain modified silica.

[0028] Thirdly, the above-mentioned side-chain modified silica has applications in the coatings field.

[0029] Fourthly, an anti-corrosion acrylic resin varnish includes: acrylic resin, polyester resin, the aforementioned side-chain modified silica, substrate wetting agent, light stabilizer, salt spray additive, and diluent.

[0030] Among them, the acrylic resin is preferably a hydroxyl acrylic resin (acrylic polyol resin);

[0031] The substrate wetting agent is selected from organosilicon surfactants; preferably, the substrate wetting agent is selected from TEGO WIN 4100;

[0032] The light stabilizer is selected from benzotriazole ultraviolet absorbers; preferably, the light stabilizer is selected from Tinuvin 99-2;

[0033] The salt spray additive is selected from inorganic-organic hybrid corrosion inhibitors; preferably, the salt spray additive is selected from HALOX 550;

[0034] The diluent is selected from any one or a combination of isopropanol, n-butanol, ethyl acetate, butyl acetate, xylene, dimethylformamide, solvent oil and propylene glycol methyl ether acetate. Preferably, the diluent is selected from a combination of butyl acetate, xylene, solvent oil and propylene glycol methyl ether acetate.

[0035] Preferably, the anti-corrosion acrylic resin varnish further includes an epoxy resin, which is selected from aliphatic epoxy resins, wherein each molecule of the epoxy resin contains at least two epoxy groups.

[0036] Furthermore, the anti-corrosion acrylic resin varnish comprises, by weight percentage: 25-45% acrylic resin, 5-15% polyester resin, 1-5% of the aforementioned side-chain modified silica, 0.1-2.5% substrate wetting agent, 0.1-2.5% light stabilizer, 1-5% salt spray additive, and 40-60% diluent;

[0037] Furthermore, the anti-corrosion acrylic resin varnish comprises, by weight percentage: 25-45% acrylic resin, 5-15% polyester resin, 1-10% aliphatic epoxy resin, 1-5% of the aforementioned side-chain modified silica, 0.1-2.5% substrate wetting agent, 0.1-2.5% light stabilizer, 1-5% salt spray additive, and 40-60% diluent.

[0038] Fifthly, the preparation method of the anti-corrosion acrylic resin varnish described above includes: first, adding acrylic resin to a mixing tank according to the formula amount and mechanically stirring it; then, adding the remaining components in the formula and mechanically stirring it; and finally, discharging the material to obtain the anti-corrosion acrylic resin varnish.

[0039] Sixthly, an anti-corrosion acrylic resin paint includes: acrylic resin, polyester resin, the aforementioned side-chain modified silica, substrate wetting agent, light stabilizer, salt spray additive, pigment, filler, and diluent.

[0040] Among them, the acrylic resin is preferably a hydroxyl acrylic resin (acrylic polyol resin);

[0041] The substrate wetting agent is selected from organosilicon surfactants; preferably, the substrate wetting agent is selected from TEGO WIN 4100;

[0042] The light stabilizer is selected from benzotriazole ultraviolet absorbers; preferably, the light stabilizer is selected from Tinuvin 99-2;

[0043] The salt spray additive is selected from inorganic-organic hybrid corrosion inhibitors; preferably, the salt spray additive is selected from HALOX 550;

[0044] The pigment is selected from any one or a combination of titanium dioxide, zinc dioxide, calcium silicate, and aluminum silicate;

[0045] The filler is selected from any one or a combination of barium sulfate, talc, calcium carbonate, silicon dioxide and mica;

[0046] The diluent is selected from any one or a combination of isopropanol, n-butanol, ethyl acetate, butyl acetate, xylene, dimethylformamide, solvent oil and propylene glycol methyl ether acetate. Preferably, the diluent is selected from a combination of butyl acetate, xylene, solvent oil and propylene glycol methyl ether acetate.

[0047] Preferably, the anti-corrosion acrylic resin paint further includes an epoxy resin, which is selected from aliphatic epoxy resins, wherein each molecule of the epoxy resin contains at least two epoxy groups.

[0048] Furthermore, the anti-corrosion acrylic resin paint, by weight percentage, comprises: 15-30% acrylic resin, 1-10% polyester resin, 1-10% of the aforementioned side-chain modified silica, 0.1-2.5% substrate wetting agent, 0.1-2.5% light stabilizer, 1-5% salt spray additive, 10-30% pigment, 5-20% filler, and 10-30% diluent.

[0049] Furthermore, the anti-corrosion acrylic resin paint, by weight percentage, comprises: 15-30% acrylic resin, 1-10% polyester resin, 1-10% aliphatic epoxy resin, 1-10% of the aforementioned side-chain modified silica, 0.1-2.5% substrate wetting agent, 0.1-2.5% light stabilizer, 1-5% salt spray additive, 10-30% pigment, 5-20% filler, and 10-30% diluent.

[0050] The seventh aspect is that the preparation method of the anti-corrosion acrylic resin paint mentioned above includes: first, adding acrylic resin to a mixing tank according to the formula amount and mechanically stirring it, then adding the remaining components in the formula and mechanically stirring it, and then grinding and dispersing the mixed slurry after stirring with a sand mill until the paint slurry fineness does not exceed 20μm, and discharging the material to obtain the anti-corrosion acrylic resin paint.

[0051] Eighthly, a coating is obtained by applying the above-described anti-corrosion acrylic resin varnish and / or anti-corrosion acrylic resin paint to the surface of a metal substrate, followed by baking and curing at 100-200°C.

[0052] The coating process includes any one of spraying, dipping, brushing, or scraping.

[0053] The metal substrate includes either carbon steel or aluminum alloy.

[0054] Preferably, the coating is obtained by baking and curing at 120-180°C; more preferably, the coating is obtained by baking and curing at 140-180°C.

[0055] Ninthly, the application of the above-mentioned anti-corrosion acrylic resin varnish and / or anti-corrosion acrylic resin paint in aircraft painting.

[0056] The beneficial effects of this invention are as follows: Based on existing aminosilane coupling agents, a silane coupling agent containing carboxyl and imino groups is synthesized through a Michael addition reaction, and then the corresponding side-chain modified silica is prepared using a sol-gel method. When the side-chain modified silica is used in anti-corrosion acrylic resin coatings, the carboxyl and imino groups in its side chains exhibit excellent reactivity with functional groups such as epoxy and hydroxyl groups in the organic resin. After baking and curing, a paint film with a higher cross-linking density can be formed, exhibiting excellent resistance to penetration by small molecule hydrocarbons, water molecules, or chloride ions. Simultaneously, the cured paint film possesses flexibility, impact resistance, and weather resistance. Attached Figure Description

[0057] Figure 1 This is a schematic diagram illustrating the process of preparing side-chain modified silica using amino-containing silane coupling agents and acrylic acid as raw materials in Examples 1 and 2.

[0058] Figure 2 XPS energy dispersive spectroscopy comparison of the side-chain modified silica prepared in Example 1 and Evonik AEROSIL 150 hydrophilic fumed silica, including overall spectrum (a), Si 2p Spectrum (b), O 1s Spectrum (c) and N 1s Spectrum (d). Detailed Implementation

[0059] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0060] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0061] Unless otherwise specified, the experimental conditions used in the examples are generally in accordance with conventional conditions in the art or the conditions recommended by the reagent company. Unless otherwise specified, the materials and reagents used in the examples can be purchased commercially.

[0062] Example 1

[0063] 36 g (0.5 mol) of acrylic acid and 0.18 g of polymerization inhibitor p-hydroxyanisole were added to a three-necked flask, followed by 80.68 g (0.45 mol) of γ-aminopropyltrimethoxysilane. Mechanical stirring was started and nitrogen gas was continuously introduced into the flask for protection. The temperature was raised to 80 °C and stirred continuously at this temperature for 12 hours. Then the temperature was lowered to room temperature and unreacted acrylic acid monomers were removed under reduced pressure at a vacuum of 0.8 torr, thereby obtaining the modified silane coupling agent.

[0064] Structural characterization of the modified silane coupling agent prepared in Example 1: 1 H NMR (CDCl3, 400 MHz): δ 1.04(2H, t, J = 2.67 Hz), 1.76 (2H, tt, J = 2.67, 2.67 Hz), 2.40-2.55 (4H, 2.47(t, J = 6.74 Hz), 2.50 (t, J = 2.67 Hz)), 2.84 (2H, t, J = 6.74 Hz), 2.99(9H, s).

[0065] A three-necked flask was prepared by adding 22.5 g of the modified silane coupling agent, 7.5 g of tetraethyl orthosilicate, and 70 g of an aqueous solution of ethanol (ethanol to water mass ratio of 13:1). Mechanical stirring was started, and nitrogen gas was continuously introduced into the flask for protection. The temperature was raised to 50°C, and the pH of the system was adjusted to 3-4 using formic acid. Then, the condensation catalyst, dibutyltin dilaurate, was added, and the temperature was raised to 80°C and maintained at this temperature for 8 hours to obtain side-chain modified silica sol. After aging at room temperature for 48 hours, the sol was vacuum dried at 80°C for 24 hours to obtain side-chain modified silica.

[0066] XPS energy spectrum comparison of the side-chain modified silica prepared in Example 1 and Evonik AEROSIL 150 hydrophilic fumed silica, including overall spectrum, Si 2p Spectrum, O 1s Spectrum and N 1s The spectrum, the specific results are as follows Figure 1 As shown.

[0067] Example 2

[0068] 36 g (0.5 mol) of acrylic acid and 0.18 g of the polymerization inhibitor p-hydroxyanisole were added to a three-necked flask, followed by 99.62 g (0.45 mol) of γ-aminopropyltriethoxysilane. Mechanical stirring was started and nitrogen gas was continuously introduced into the flask for protection. The temperature was raised to 80 °C and stirred continuously at this temperature for 12 hours. Then the temperature was lowered to room temperature and unreacted acrylic acid monomers were removed under reduced pressure at a vacuum of 0.8 torr, thereby obtaining the modified silane coupling agent.

[0069] Structural characterization of the modified silane coupling agent: 1 H NMR (CDCl3,400 MHz): δ 0.97 (2H, t, J =2.67 Hz), 1.32 (9H, t, J = 6.90 Hz), 1.76 (2H, tt, J = 2.67, 2.67 Hz), 2.40-2.56 (4H, 2.47 (t, J = 6.74 Hz), 2.50 (t, J = 2.67 Hz)), 2.84 (2H, t, J =6.74 Hz), 3.40 (6H, q, J = 6.90 Hz).

[0070] An aqueous solution of 21.5 g of the modified silane coupling agent, 8.5 g of tetraethyl orthosilicate, and 70 g of ethanol (ethanol to water mass ratio of 13:1) was added to a three-necked flask. Mechanical stirring was started, and nitrogen gas was continuously introduced into the flask for protection. The temperature was raised to 50°C, and the pH of the system was adjusted to 3-4 using acetic acid. Then, the condensation catalyst dibutyltin dilaurate was added, and the temperature was raised to 80°C and maintained at this temperature for 8 hours to obtain side-chain modified silica sol. After cooling to room temperature and aging for 48 hours, the sol was vacuum dried at 80°C for 24 hours to obtain side-chain modified silica.

[0071] Example 3

[0072] The anti-corrosion acrylic resin varnish comprises, by weight percentage: 36% acrylic polyol resin, 9% polyester resin, 2.5% side-chain modified silica prepared in Example 1, 0.5% substrate wetting agent, 1.0% light stabilizer, 3% salt spray additive, and 48% diluent;

[0073] Preparation of anti-corrosion acrylic resin varnish: Acrylic polyol resin CFU1955A (Carvro) was added to a mixing tank according to the formula. While stirring with a dispersing disc at 600 rpm, the following components were added: polyester resin CFS6528W (Carvro), diluent, side-chain modified silica prepared in Example 1, substrate wetting agent TEGO WIN 4100 (Evonik), light stabilizer Tinuvin 99-2 (BASF), and salt spray additive HALOX 550 (Fabble). The diluent included butyl acetate, environmentally friendly solvent oil D40, and xylene and propylene glycol methyl ether acetate (the diluent ratio by mass was 6:1:2:1). After adding all the ingredients, stirring was continued at 1200 rpm for 30 minutes, followed by filtration and discharge to obtain the anti-corrosion acrylic resin varnish.

[0074] Example 4

[0075] The anti-corrosion acrylic resin varnish comprises, by weight percentage: 35% acrylic polyol resin, 7% polyester resin, 4% aliphatic epoxy resin, 2.5% side-chain modified silica prepared in Example 2, 0.5% substrate wetting agent, 1.0% light stabilizer, 3% salt spray additive, and 47% diluent;

[0076] Preparation of anti-corrosion acrylic resin varnish: Acrylic polyol resin CFU1955A (Carfule) was added to a mixing tank according to the formula. While stirring with a dispersing disc at 600 rpm, the following components were added: polyester resin CFS6528W (Carfule), diluent, side-chain modified silica prepared in Example 2, aliphatic epoxy resin DYD-505 (Deyu, epoxy equivalent 380), substrate wetting agent TEGO WIN 4100 (Evonik), light stabilizer Tinuvin 99-2 (BASF), and salt spray additive HALOX 550 (Fabble). The diluent included butyl acetate, environmentally friendly solvent oil D40, and xylene and propylene glycol methyl ether acetate (the diluent ratio by mass was 6:1:2:1). After adding all the ingredients, stirring was continued at 1200 rpm for 30 minutes, followed by filtration and discharge to obtain the anti-corrosion acrylic resin varnish.

[0077] Example 5

[0078] The anti-corrosion acrylic resin varnish, by weight percentage, comprises: 35% acrylic polyol resin, 7% polyester resin, 3.5% aliphatic epoxy resin, 2.5% side-chain modified silica prepared in Example 1, 0.5% substrate wetting agent, 1.0% light stabilizer, 3% salt spray additive, and 47.5% diluent;

[0079] Preparation of anti-corrosion acrylic resin varnish: Acrylic polyol resin CFU1955A (Carfule) was added to a mixing tank according to the formula. While stirring at 600 rpm using a dispersion disc, the following components were added: polyester resin CFS6528W (Carfule), diluent, side-chain modified silica prepared in Example 1, aliphatic epoxy resin CYE-001 (Chenyuan, epoxy equivalent 202), substrate wetting agent TEGO WIN 4100 (Evonik), light stabilizer Tinuvin 99-2 (BASF), and salt spray additive HALOX 550 (Fabble). The diluent included butyl acetate, environmentally friendly solvent oil D40, and xylene and propylene glycol methyl ether acetate (the diluent ratio by mass was 6:1:2:1). After adding all the ingredients, stirring was continued at 1200 rpm for 30 minutes using a dispersion disc. The mixture was then filtered and discharged to obtain the anti-corrosion acrylic resin varnish.

[0080] Example 6

[0081] The anti-corrosion acrylic resin varnish, by weight percentage, comprises: 35% acrylic polyol resin, 7% polyester resin, 2.5% aliphatic epoxy resin, 2.5% side-chain modified silica prepared in Example 2, 0.5% substrate wetting agent, 1.0% light stabilizer, 3% salt spray additive, and 48.5% diluent;

[0082] Preparation of anti-corrosion acrylic resin varnish: Acrylic polyol resin CFU1955A (Carfule) was added to a mixing tank according to the formula. While stirring at 600 rpm using a dispersion disc, the following components were added: polyester resin CFS6528W (Carfule), diluent, side-chain modified silica prepared in Example 2, aliphatic epoxy resin CYE-003 (Chenyuan, epoxy equivalent 251), substrate wetting agent TEGO WIN 4100 (Evonik), light stabilizer Tinuvin 99-2 (BASF), and salt spray additive HALOX 550 (Fabble). The diluent included butyl acetate, environmentally friendly solvent oil D40, and xylene and propylene glycol methyl ether acetate (the diluent ratio by mass was 6:1:2:1). After adding all the ingredients, stirring was continued at 1200 rpm for 30 minutes using a dispersion disc. The mixture was then filtered and discharged to obtain the anti-corrosion acrylic resin varnish.

[0083] Example 7

[0084] The anti-corrosion acrylic resin paint, by weight percentage, comprises: 24% acrylic polyol resin, 6% polyester resin, 7.5% aliphatic epoxy resin, 4.5% side-chain modified silica prepared in Example 1, 20% titanium dioxide, 5% precipitated barium sulfate, 5% talc, 0.5% substrate wetting agent, 1.0% light stabilizer, 3% salt spray additive, and 23.5% diluent.

[0085] Preparation of anti-corrosion acrylic resin paint: Add acrylic polyol resin CFU1955A (Carfule) to a mixing tank according to the formula amount. While stirring with a dispersing disc at 600 rpm, add polyester resin CFS6528W (Carfule), diluent, side-chain modified silica prepared in Example 2, aliphatic epoxy resin DYD-505 (Deyu, epoxy equivalent 380), substrate wetting agent TEGO WIN 4100 (Evonik), light stabilizer Tinuvin 99-2 (BASF), and salt spray additive HALOX 550 (Fabble). The diluent includes butyl acetate, environmentally friendly solvent oil D40, xylene and propylene glycol methyl ether acetate (the ratio of diluent by mass is 6:1:2:1). After adding all the ingredients, continue stirring at 1200 rpm for 30 minutes using a dispersing disc, then filter and discharge the mixture. The resulting slurry is then ground and dispersed using a sand mill until the paint slurry fineness is below 20 μm. After further filtration, the anti-corrosion acrylic resin paint is obtained.

[0086] Example 8

[0087] The anti-corrosion acrylic resin paint, by weight percentage, comprises: 24% acrylic polyol resin, 6% polyester resin, 6.5% aliphatic epoxy resin, 4.5% side-chain modified silica prepared in Example 2, 20% titanium dioxide, 5% precipitated barium sulfate, 5% talc, 0.5% substrate wetting agent, 1.0% light stabilizer, 3% salt spray additive, and 21.5% diluent.

[0088] Preparation of anti-corrosion acrylic resin paint: Add acrylic polyol resin CFU1955A (Carfule) to a mixing tank according to the formula amount. While stirring with a dispersing disc at 600 rpm, add polyester resin CFS6528W (Carfule), diluent, side-chain modified silica prepared in Example 2, aliphatic epoxy resin CYE-001 (Chenyuan, epoxy equivalent 202), substrate wetting agent TEGO WIN 4100 (Evonik), light stabilizer Tinuvin 99-2 (BASF), and salt spray additive HALOX 550 (Fabble). The diluent includes butyl acetate, environmentally friendly solvent oil D40, xylene and propylene glycol methyl ether acetate (the ratio of diluent by mass is 6:1:2:1). After adding all the ingredients, continue stirring at 1200 rpm for 30 minutes using a dispersing disc, then filter and discharge the mixture. The resulting slurry is then ground and dispersed using a sand mill until the paint slurry fineness is below 20 μm. After further filtration, the anti-corrosion acrylic resin paint is obtained.

[0089] Comparative Example 1

[0090] The anti-corrosion acrylic resin varnish, by weight percentage, comprises: 35% acrylic polyol resin, 7% polyester resin, 3.5% aliphatic epoxy resin, 2.5% fumed silica, 0.5% substrate wetting agent, 1.0% light stabilizer, 3% salt spray additive, and 47.5% diluent;

[0091] Preparation of Anti-corrosion Acrylic Resin Clear Varnish: Add acrylic polyol resin CFU1955A (Carvro) to a mixing tank according to the formula. While stirring with a dispersing disc at 600 rpm, add the following components from the formula: polyester resin CFS6528W (Carvro), diluent, Evonik AEROSIL 150 hydrophilic fumed silica, aliphatic epoxy resin CYE-001 (Chenyuan, epoxy equivalent 202), substrate wetting agent TEGO WIN 4100 (Evonik), light stabilizer Tinuvin 99-2 (BASF), and salt spray additive HALOX 550 (Fabble). The diluent includes butyl acetate, environmentally friendly solvent oil D40, and xylene and propylene glycol methyl ether acetate (the diluent ratio by mass is 6:1:2:1). After adding all the ingredients, continue stirring with a dispersing disc at 1200 rpm for 30 minutes, then filter and discharge to obtain the anti-corrosion acrylic resin clear varnish.

[0092] Comparative Example 2

[0093] The anti-corrosion acrylic resin varnish, by weight percentage, comprises: 35% acrylic polyol resin, 7% polyester resin, 3.5% bisphenol A type epoxy resin, 2.5% side-chain modified silica prepared in Example 1, 0.5% substrate wetting agent, 1.0% light stabilizer, 3% salt spray additive, and 47.5% diluent;

[0094] Preparation of anti-corrosion acrylic resin varnish: Add acrylic polyol resin CFU1955A (Carfule) to a mixing tank according to the formula amount. While stirring with a dispersing disc at 600 rpm, add polyester resin CFS6528W (Carfule), diluent, 175B bisphenol A type epoxy resin (Xi'an Zhilun, epoxy equivalent 171), side-chain modified silica prepared in Example 1, aliphatic epoxy resin CYE-001 (Chenyuan, epoxy equivalent 202), substrate wetting agent TEGO WIN 4100 (Evonik), light stabilizer Tinuvin 99-2 (BASF), and salt spray additive HALOX 550 (Faberhe). The diluent includes butyl acetate, environmentally friendly solvent oil D40, xylene and propylene glycol methyl ether acetate (the ratio of diluent by mass is 6:1:2:1). After adding all the ingredients, continue stirring in a dispersing pan at 1200 rpm for 30 minutes, then filter and discharge to obtain anti-corrosion acrylic resin varnish.

[0095] Comparative Example 3

[0096] The anti-corrosion acrylic resin paint, by weight percentage, comprises: 24% acrylic polyol resin, 6% polyester resin, 6.5% aliphatic epoxy resin, 4.5% fumed silica, 20% titanium dioxide, 5% precipitated barium sulfate, 5% talc, 0.5% substrate wetting agent, 1.0% light stabilizer, 3% salt spray additive, and 21.5% thinner.

[0097] Preparation of anti-corrosion acrylic resin paint: Add acrylic polyol resin CFU1955A (Carvro) to a mixing tank according to the formula amount. While stirring with a dispersing disc at 600 rpm, add polyester resin CFS6528W (Carvro), diluent, Evonik AEROSIL 150 hydrophilic fumed silica, aliphatic epoxy resin CYE-001 (Chenyuan, epoxy equivalent 202), substrate wetting agent TEGO WIN 4100 (Evonik), light stabilizer Tinuvin 99-2 (BASF), and salt spray additive HALOX 550 (Faberhe). The diluent includes butyl acetate, environmentally friendly solvent oil D40, xylene and propylene glycol methyl ether acetate (the ratio of diluent by mass is 6:1:2:1). After adding all the ingredients, continue stirring at 1200 rpm for 30 minutes using a dispersing disc, then filter and discharge the mixture. The resulting slurry is then ground and dispersed using a sand mill until the paint slurry fineness is below 20 μm. After further filtration, the anti-corrosion acrylic resin paint is obtained.

[0098] The anti-corrosion acrylic resin varnishes or paints prepared in Examples 3-8 and Comparative Examples 1-3 were subjected to performance tests. The performance tests included: adhesion, flexibility, impact resistance, and low-temperature impact resistance. The paint films were prepared on test-grade tinplate (70mm×150mm×0.28mm). The paint films for resistance to aviation fuel and aviation hydraulic oil, as well as electrochemical impedance spectroscopy, were prepared on anodized aluminum plates (75mm×70mm×0.8mm). The paint films for salt spray resistance and weather resistance were prepared on anodized aluminum plates (70mm×150mm×1mm). The dry film thickness was 25±2μm. The curing method was thermosetting, and the curing conditions were 160℃*30min. The performance tests were conducted after the paint films had dried for 7 days.

[0099] Performance testing methods: Adhesion testing follows the ISO 2409:2020 standard; flexibility testing follows the GB / T 1731-2020 standard; impact resistance testing follows the GB / T 1732-2020 standard; high and low temperature cyclic impact resistance follows the CMS-CT-102 standard 6.2.14 standard; resistance to aviation fuel and aviation hydraulic oil follows the GB / T 9274-1988 standard, using RP-3 aviation fuel with a kinematic viscosity of 0.768 mm. 2 / s (100℃, 0.1MPa), the aviation hydraulic oil is YH-15 aviation hydraulic oil, with a kinematic viscosity of 5.564 mm. 2 / s (100℃, 0.1MPa); Salt spray resistance test according to GB / T1771-2007 test method; Weather resistance test according to GB / T 1865-2009 test method.

[0100] The method for rapidly evaluating corrosion protection effects using electrochemical impedance spectroscopy (EIS) includes: using a Chi660e electrochemical workstation and a three-electrode system for EIS testing. Anodized aluminum substrate is used as the working electrode, a calomel electrode as the reference electrode, a graphite rod as the counter electrode, and a 3.5 wt% NaCl solution as the electrolyte. Before testing, a corner of the coated aluminum plate is sanded off with 800-grit sandpaper to completely expose the aluminum substrate. In the experiment, a three-electrode system is first constructed, and the EIS test is performed only after the open-circuit potential has stabilized. The frequency range for the impedance test is selected to be 10 Hz. -2 Hz~10 5 Hz, signal amplitude 10 mV, finally recorded at 10 -2 Impedance value |Z| at Hz.

[0101] The test results of the anti-corrosion acrylic resin varnishes or paints prepared in Examples 3-8 and Comparative Examples 1-3 are listed in Table 1. Analysis of the test data in Table 1 shows that the paint films of Examples 3-8, after adding the side-chain modified silica prepared in Examples 1 or 2, exhibit an impact resistance of no less than 50 cm. After 24 cycles of high and low temperature cycling, the paint films showed no cracking or peeling in the impact test. They also showed good tolerance to aviation fuels and aviation hydraulic oils of different kinematic viscosities, and the paint films showed no abnormalities after 30 days of immersion. Furthermore, the anti-corrosion acrylic resin varnishes or paints of Examples 3-8 have higher anti-corrosion effects and weather resistance compared to Comparative Examples 1 and 3. -2The impedance value |Z| at Hz, as well as the salt spray test and weather resistance test, show significantly better results. This is because the side-chain modified silica introduces carboxyl and imino side chains, which have good reactivity with functional groups such as epoxy and hydroxyl groups in organic resins. Under baking and heating conditions, it can form a paint film with a higher cross-linking density, which has a good resistance to penetration of small molecule hydrocarbons, water molecules or chloride ions.

[0102] Compared with Comparative Example 2, the paint films prepared in Examples 3-8 have significantly better impact resistance and weather resistance. This is because Examples 3-8 did not add epoxy resin or used aliphatic epoxy resin, thus avoiding the introduction of bisphenol A structure. After curing, the paint films have better impact resistance and resistance to artificial aging.

[0103] Table 1

[0104] Test sample Adhesion (grade) Flexibility (mm) Impact resistance (cm) Resistance to high-low temperature cycle (24 cycles at 71°C to -54°C) Resistance to RP-3 aviation fuel for 30 days Resistance to YH-15 aviation hydraulic oil for 30 days |Z| 0.01Hz (ohm) Salt spray resistance (h) Weather resistance (1500 h) Example 3 0 0.5 55 No cracks, no peeling No abnormalities No abnormalities 1.490 x 10 9 ]]> ＞2250 Gloss retention > 90% Example 4 0 0.5 55 No cracks, no peeling No abnormalities No abnormalities 1.676 x 10 9 ]] ＞2250 Gloss retention > 90% Example 5 0 0.5 50 No cracks, no peeling No abnormalities No abnormalities 2.550 x 10 9 ]] ＞2250 Gloss retention > 90% Example 6 0 0.5 50 No cracks, no peeling No abnormalities No abnormalities 3.364 x 10 9 ]] ＞2250 Gloss retention > 90% Example 7 0 1.0 50 No cracks, no peeling No abnormalities No abnormalities 4.610 x 10 9 ]]> ＞2250 Gloss retention > 90% Example 8 0 1.0 50 No cracks, no peeling No abnormalities No abnormalities 5.809 x 10 9 ]]> ＞2250 Gloss retention > 90% Comparative Example 1 0 1.0 50 No cracks, no peeling Whitish discoloration, wrinkling Slight discoloration 1.234 x 10 8 ]]> 1464 Gloss retention > 90% Comparative Example 2 0 1.0 40 Slight cracking No abnormalities No abnormalities 2.061 x 10 9 ]]> ＞2250 Gloss retention 47% Comparative Example 3 1 1.5 45 Slight cracking Whitish discoloration Slight discoloration 6.744 x 10 8 ]]> 1848 Gloss retention 86%

[0105] Comparative Example 1's anti-corrosion acrylic resin varnish and Comparative Example 3's anti-corrosion acrylic resin paint both used fumed silica instead of side-chain modified silica. Fumed silica contains hydroxyl groups on its surface, which can participate in the cross-linking reaction of organic resins, but the lack of organic segments leads to poor reactivity with organic resins. As a result, the cured paint film has low impact resistance and poor resistance to hydrocarbons (aviation fuel and aviation hydraulic oil) with different kinematic viscosities. The paint film shows varying degrees of swelling. According to the EIS test and salt spray test results, the anti-corrosion effect of Comparative Examples 1 and 3 is poor, indicating that the cross-linking density of their cured paint film is low and the resistance to penetration of small molecule hydrocarbons, water molecules or chloride ions is insufficient.

[0106] In Comparative Example 2, the anti-corrosion acrylic resin varnish with added bisphenol A epoxy resin exhibited poor flexibility and impact resistance after curing. This is attributed to the presence of numerous benzene rings in the resin's chain segments, leading to a reduction in free volume. Furthermore, the benzene rings in the bisphenol A epoxy resin readily undergo photo-oxidation reactions with oxygen under high-energy ultraviolet light, generating free radicals. This results in the cleavage of the polymer's main chain, manifesting macroscopically as chalking and loss of gloss in weathering tests, ultimately causing the varnish to age and fail.

[0107] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of them. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention. Although the specific embodiments of the present invention have been described above, they are not intended to limit the protection scope of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A corrosion-resistant acrylic resin varnish, characterized in that, The anti-corrosion acrylic resin varnish includes: hydroxyl acrylic resin, polyester resin, aliphatic epoxy resin, side-chain modified silica, substrate wetting agent, light stabilizer, salt spray additive and diluent; The substrate wetting agent is selected from organosilicon surfactants; The light stabilizer is selected from benzotriazole ultraviolet absorbers; The salt spray additive is selected from inorganic-organic hybrid corrosion inhibitors; The diluent is selected from any one or a combination of isopropanol, n-butanol, ethyl acetate, butyl acetate, xylene, dimethylformamide, solvent oil and propylene glycol methyl ether acetate; Each molecule of the aliphatic epoxy resin contains at least two epoxy groups; The side chain of the modified silica comprises 3 to 20 carbon atoms, and at least one carboxyl group and an amino group; wherein the amino group includes a primary amino group or a secondary amino group.

2. The anti-corrosion acrylic resin varnish according to claim 1, characterized in that, The anti-corrosion acrylic resin varnish comprises, by weight percentage: 25-45% hydroxyl acrylic resin, 5-15% polyester resin, 1-10% aliphatic epoxy resin, 1-5% side-chain modified silica, 0.1-2.5% substrate wetting agent, 0.1-2.5% light stabilizer, 1-5% salt spray additive, and 40-60% diluent.

3. A method for preparing an anti-corrosion acrylic resin varnish as described in any one of claims 1-2, characterized in that, Hydroxy acrylic resin is added to a mixing tank according to the formula and mechanically stirred. Then, the remaining components in the formula are added and mechanically stirred before the material is discharged.

4. A corrosion-resistant acrylic resin paint, characterized in that, Anti-corrosion acrylic resin paints include: hydroxyl acrylic resin, polyester resin, aliphatic epoxy resin, side-chain modified silica, substrate wetting agent, light stabilizer, salt spray additive, pigment, filler and diluent; The substrate wetting agent is selected from organosilicon surfactants; The light stabilizer is selected from benzotriazole ultraviolet absorbers; The salt spray additive is selected from inorganic-organic hybrid corrosion inhibitors; The pigment is selected from any one or a combination of titanium dioxide, zinc dioxide, calcium silicate, and aluminum silicate; The filler is selected from any one or a combination of barium sulfate, talc, calcium carbonate, silicon dioxide and mica; The diluent is selected from any one or a combination of isopropanol, n-butanol, ethyl acetate, butyl acetate, xylene, dimethylformamide, solvent oil and propylene glycol methyl ether acetate; Each molecule of the aliphatic epoxy resin contains at least two epoxy groups; The side chain of the modified silica comprises 3 to 20 carbon atoms, and at least one carboxyl group and an amino group; wherein the amino group includes a primary amino group or a secondary amino group.

5. The anti-corrosion acrylic resin paint according to claim 1, characterized in that, The anti-corrosion acrylic resin paint, by weight percentage, comprises: 15-30% hydroxyl acrylic resin, 1-10% polyester resin, 1-10% aliphatic epoxy resin, 1-10% of the above-mentioned side-chain modified silica, 0.1-2.5% substrate wetting agent, 0.1-2.5% light stabilizer, 1-5% salt spray additive, 10-30% pigment, 5-20% filler, and 10-30% diluent.

6. A method for preparing an anti-corrosion acrylic resin paint as described in any one of claims 4-5, characterized in that, Hydroxy acrylic resin is added to a mixing tank according to the formula and mechanically stirred. Then, the remaining components in the formula are added and mechanically stirred. The mixed slurry is then ground and dispersed by a sand mill until the fineness of the paint slurry does not exceed 20μm before being discharged.

7. A method for preparing side-chain modified silica for use in the anti-corrosion acrylic resin varnish according to any one of claims 1-2 or the anti-corrosion acrylic resin colored paint according to any one of claims 4-5, characterized in that, First, an amino-containing silane coupling agent is added to acrylic acid or carboxyacrylate to obtain a modified silane coupling agent, which is then condensed with an orthosilicate organic ester to prepare the modified silane coupling agent. The amino-containing silane coupling agent is selected from any one or more of the following: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, N-aminoethyl-3-aminopropyltrimethoxysilane, or N-aminoethyl-3-aminopropylmethyldiethoxysilane. The organic ester of orthosilicate is selected from any one of methyl orthosilicate, ethyl orthosilicate, or propyl orthosilicate.

8. The method for preparing side-chain modified silica according to claim 7, characterized in that, In the reactants of the addition reaction, the molar ratio of the amino-containing silane coupling agent to acrylic acid or carboxyacrylate is (0.8-1.0):

1.

9. The method for preparing side-chain modified silica according to claim 7, characterized in that, The addition reaction uses a polymerization inhibitor, which is selected from phenolic polymerization inhibitors.

10. The method for preparing side-chain modified silica according to claim 7, characterized in that, The addition reaction is carried out at a temperature of 60-120℃.

11. The method for preparing side-chain modified silica according to claim 7, characterized in that, In the reactants of the condensation reaction, the molar ratio of the modified silane coupling agent to the organic ester of orthosilicate is (2-4):

1.

12. The method for preparing side-chain modified silica according to claim 7, characterized in that, The condensation reaction also uses a solvent, with a solvent-to-reactant mass ratio of (1-2.5):1; the solvent includes: alcohol solvent and water, wherein the alcohol solvent-to-water mass ratio is (10-20):

1.

13. The method for preparing side-chain modified silica according to claim 7, characterized in that, The condensation reaction uses formic acid or acetic acid to adjust the pH of the reaction system to 3-4.

14. The method for preparing side-chain modified silica according to claim 7, characterized in that, The condensation reaction is carried out at a temperature of 50-100℃.

15. The method for preparing side-chain modified silica according to claim 7, characterized in that, The condensation reaction uses dibutyltin dilaurate as a catalyst.

16. The method for preparing side-chain modified silica according to claim 7, characterized in that, The preparation method of the side-chain modified silica includes: after the condensation reaction is completed, it is left to stand at room temperature for 12-48 hours for aging.

17. The method for preparing side-chain modified silica according to claim 7, characterized in that, The preparation method of the side-chain modified silica includes: after aging, vacuum drying at 80-100℃ for 12-48h to obtain side-chain modified silica.

18. A coating, characterized in that, The anti-corrosion acrylic resin varnish as described in any one of claims 1-2 or the anti-corrosion acrylic resin paint as described in any one of claims 4-5 is coated on the surface of a metal substrate and then baked and cured at 100-200°C. The coating process includes any one of spraying, dipping, brushing, or scraping.

19. The coating according to claim 18, characterized in that, The metal substrate includes either carbon steel or aluminum alloy.

20. An application characterized in that, The application of the anti-corrosion acrylic resin varnish as described in any one of claims 1-2 or the anti-corrosion acrylic resin paint as described in any one of claims 4-5 in aircraft painting.

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