Weather-proof transparent anticorrosive environment-friendly coating and preparation method thereof

Abstract

The invention discloses a weather-resistant transparent anticorrosive environment-friendly coating and a preparation method thereof. A formula of the weather-resistant transparent anti-corrosion environment-friendly coating comprises the following components in parts by mass: 30-45 parts of water-based acrylic resin, 2-5 parts of nano titanium dioxide, 1-3 parts of an organic silane coupling agent, 3-6 parts of an environment-friendly coalescing agent, 1-4 parts of an anti-corrosion corrosion inhibitor, 1-3 parts of a defoaming agent and 20-35 parts of deionized water. According to the invention, a specific compound containing a quinazoline structure is used as an anti-corrosion corrosion inhibitor to replace a traditional heavy metal-containing or high-toxicity anti-corrosion component, so that the ecological environment harm and human health risk in the use process of the coating are fundamentally eliminated. Meanwhile, the corrosion-resistant corrosion inhibitor forms a compact protective film on the metal surface through chemical adsorption and passivation, erosion of oxygen, moisture and corrosive media is effectively blocked, the corrosion-resistant efficiency of the corrosion-resistant corrosion inhibitor is remarkably superior to that of a conventional environment-friendly corrosion inhibitor, and double breakthrough of environment friendliness and corrosion resistance is achieved.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating and its preparation method. Background Technology

[0002] With the development of modern industry, coatings are increasingly widely used in shipbuilding, aerospace, rail transportation, marine engineering, and building curtain walls. Among them, transparent protective coatings, which require both long-term anti-corrosion performance and preservation of the original appearance of the substrate, have become a research hotspot in the field of coating technology due to their special requirements in high-end scenarios such as metal decorative parts, glass curtain walls, and wooden components.

[0003] In existing technologies, traditional coatings rely heavily on heavy metals such as chromium and lead, or highly toxic anti-corrosion components, to achieve effective corrosion protection. While these coatings can form a passivation film on the metal surface and provide corrosion protection, they pose serious environmental hazards and risks to human health, and are gradually failing to meet increasingly stringent environmental regulations. Although water-based environmentally friendly coatings have seen some development in recent years, existing environmentally friendly anti-corrosion coatings generally suffer from insufficient corrosion protection efficiency, especially when facing harsh marine or industrial atmospheric environments, where their long-term protective capabilities are insufficient to meet usage requirements.

[0004] Furthermore, in the field of transparent coatings, existing technologies face a technical bottleneck where transparency and functionality are difficult to balance. On the one hand, conventional corrosion inhibitors or functional fillers added to improve corrosion resistance often lead to decreased coating transparency, obscuring the original appearance of the substrate. On the other hand, transparent coatings are prone to yellowing, loss of gloss, chalking, and cracking under long-term ultraviolet light exposure, resulting in a shortened protection period and affecting appearance. Simultaneously, the dispersion stability of nano-functional particles in existing transparent coatings is poor, easily leading to aggregation and light scattering, further affecting coating transparency. Although there are reports of using organosilane coupling agents to improve interfacial bonding, how to simultaneously achieve stable dispersion of nanoparticles, high coating transparency, and long-term corrosion and weather resistance in aqueous systems remains a pressing technical challenge to be solved in this field.

[0005] Therefore, developing a coating that combines excellent environmental friendliness, high transparency, long-lasting corrosion resistance, and outstanding weather resistance is of great practical significance for meeting high-end protection needs. Summary of the Invention

[0006] The purpose of this invention is to address the problems existing in the prior art by providing a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating and its preparation method. This coating is based on an environmentally friendly formula, contains no heavy metals or high VOC components, and possesses excellent transparency, corrosion resistance, and weather resistance. It effectively avoids substrate corrosion and aging and appearance obscuration, thereby improving the green protection requirements. Furthermore, this weather-resistant, transparent, anti-corrosion, and environmentally friendly coating is a curable coating.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A weather-resistant, transparent, anti-corrosion, and environmentally friendly coating is prepared from the following components in parts by weight: 30-45 parts water-based acrylic resin, 2-5 parts nano titanium dioxide, 1-3 parts organosilane coupling agent, 3-6 parts environmentally friendly film-forming aid, 1-4 parts corrosion inhibitor, 1-3 parts defoamer, and 20-35 parts deionized water. The corrosion inhibitor is a compound represented by Formula 1; The structure of Equation 1 is as follows: ; By adopting the above technical solution, the glass transition temperature of the waterborne acrylic resin is -10℃ to 25℃, and the solid content is 40%-55%.

[0008] Furthermore, by adopting the above technical solution, the particle size of the nano-titanium dioxide is 1-20nm, and it has undergone hydrophobic modification treatment.

[0009] By adopting the above technical solution, the organosilane coupling agent is further... Aminopropyltriethoxysilane.

[0010] Furthermore, by adopting the above technical solution, the environmentally friendly film-forming aid is propylene glycol methyl ether acetate, and the VOC content is ≤50g / L.

[0011] Furthermore, by adopting the above technical solution, the corrosion inhibitor is any one of the compounds shown in the following structures: .

[0012] By adopting the above technical solution, further, the... It can be any one of halogen, methyl, cyano, trifluoromethyl, or nitro.

[0013] By adopting the above technical solution, the corrosion inhibitor of the present invention can further complex with harmful ions in the corrosive medium, reduce ion activity, and prevent them from damaging the passivation film on the metal surface.

[0014] Furthermore, by adopting the above technical solution, the defoamer is an organosilicon defoamer.

[0015] S1. Pre-dispersion: Add the deionized water and organosilane coupling agent to a dispersion vessel, stir at 300-500 r / min for 10-15 min to obtain a pre-dispersion; S2. Nanoparticle dispersion: Add the nano-titanium dioxide to the above pre-dispersion liquid, adjust the stirring speed to 1200-1500 r / min, disperse for 20-30 min, and then use ultrasonic dispersion treatment for 10-25 min to obtain nano-dispersion liquid; S3. Base material mixing: Add the aqueous acrylic resin to the above nano-dispersion, maintain the stirring speed at 800-1000 r / min, and stir for 15-25 min to obtain the base material mixture; S4. Addition of functional additives: Under nitrogen protection, the environmentally friendly film-forming aid, corrosion inhibitor, and defoamer are added sequentially to the above base mixture. The stirring speed is adjusted to 600-800 r / min, and the mixture is stirred for 15-30 min to obtain a preliminary anti-corrosion and environmentally friendly coating. The coating is then filtered to remove impurities and incompletely dispersed particles. After sealing and packaging, the weather-resistant and transparent anti-corrosion and environmentally friendly coating is obtained.

[0016] Furthermore, in S2, the power of ultrasonic dispersion is 1500-2500W, the frequency is 20-40kHz, and the system temperature is controlled not to exceed 40℃ during the dispersion process.

[0017] Furthermore, the addition rate of the water-based acrylic resin in S3 is 1-2 parts / min.

[0018] The present invention relates to the application of a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating in the field of coating technology.

[0019] The weather-resistant, transparent, anti-corrosion, and environmentally friendly coating described in this invention is suitable for use in fields such as ships, aircraft, high-speed rail, and marine engineering.

[0020] The weather-resistant, transparent, anti-corrosion, and environmentally friendly coating described in this invention can be used in curing coatings.

[0021] The weather-resistant, transparent, anti-corrosion, and environmentally friendly coating described in this invention is a curable coating. Its synergistic formulation solves the core problem in existing technologies where it is difficult to simultaneously achieve environmental friendliness, transparency, corrosion resistance, and weather resistance in anti-corrosion coatings. Using water-based acrylic resin as the base material ensures the coating's transparency to preserve the original appearance of the substrate, while also possessing good film-forming properties and adhesion. Its water-based system effectively avoids high VOC pollution. Nano-titanium dioxide and γ-aminopropyltriethoxysilane work synergistically to enhance weather resistance by utilizing the UV shielding effect of nanoparticles, preventing yellowing and cracking of the coating. On the other hand, coupling agents enhance the compatibility of each component and the adhesion to the substrate, reducing the risk of interlayer delamination. Environmentally friendly film-forming aids optimize film-forming quality and ensure coating density without compromising environmental friendliness and transparency. Corrosion inhibitors with specific structures form a protective film through chemical adsorption and passivation, effectively resisting the erosion of oxygen, moisture, etc., replacing traditional toxic heavy metal anti-corrosion components and effectively improving environmentally friendly anti-corrosion performance. Organosilicon defoamers eliminate bubbles generated during the preparation process, preventing pore defects in the coating and ensuring anti-corrosion and transparency effects. Meanwhile, the pre-dispersion, ultrasonic-assisted nanoparticle dispersion, and addition of additives under a nitrogen atmosphere during the preparation process further promote the uniform mixing of each component, enhance the synergistic effect, and solve the comprehensive performance improvement of the coating in terms of environmental protection and harmlessness, transparency and preservation of substrate appearance, long-term corrosion protection and weather resistance, thus ensuring the stability of material use.

[0022] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses a specific compound containing a quinazoline structure as a corrosion inhibitor, replacing traditional corrosion inhibitors containing heavy metals or highly toxic substances, fundamentally eliminating the environmental hazards and human health risks during the application of the coating. Simultaneously, this corrosion inhibitor forms a dense protective film on the metal surface through chemical adsorption and passivation, effectively blocking the erosion of oxygen, moisture, and corrosive media. Its corrosion resistance is significantly superior to conventional environmentally friendly corrosion inhibitors, achieving a dual breakthrough in environmental friendliness and corrosion resistance, resulting in a superior curable coating.

[0023] 2. This invention uses water-based acrylic resin as a base material, combined with hydrophobically modified nano-titanium dioxide and γ-aminopropyltriethoxysilane coupling agent, to construct a uniform and stable transparent coating system. The ultraviolet shielding effect of nano-titanium dioxide effectively inhibits coating yellowing and substrate photoaging, while the organosilane coupling agent enhances the compatibility of each component and coating adhesion. This allows the coating to maintain a high transparency of over 90% while possessing excellent weather resistance and long-term protective capabilities, solving the technical bottlenecks of traditional curable coatings that are prone to gloss loss, cracking, and short protection periods.

[0024] 3. This invention optimizes processes such as pre-dispersion, ultrasonic-assisted nanoparticle dispersion, and addition of functional additives under a nitrogen atmosphere to ensure uniform mixing of all components and stable dispersion of nanoparticles. The preparation process is simple to operate, mild under mild conditions, and easy to industrialize. The resulting coating has a VOC content ≤50g / L, meeting green and environmentally friendly coating standards. Furthermore, it exhibits excellent comprehensive properties such as film hardness, adhesion, water resistance, and chemical resistance, making it widely applicable to high-end curable coating protection scenarios where the original appearance of the substrate must be preserved, such as glass curtain walls, wooden components, and metal decorative parts. Attached Figure Description

[0025] Figure 1 The above are FTIR comparison spectra of Example 1 and the control sample (without corrosion inhibitor 1) of the present invention.

[0026] Figure 2 This is the UV-Vis transmittance spectrum of the coating film in Example 1 of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Preparation Example 1 Preparation of corrosion inhibitor 1: ; Compound 1: 4-(4-bromo-2-fluorophenoxy)-6-methoxyquinazoline-7-ol; Compound 2: 4-Fluoro-2-methoxybenzoyl chloride; Intermediate 1: 4-(4-bromo-2-fluorophenoxy)-6-methoxyquinazoline-7-yl 4-fluoro-2-methoxybenzoate; Under nitrogen protection, compound 1 (3.00 g) was added to a dry reaction flask, and anhydrous dichloromethane (40 mL) was added to disperse it. After stirring evenly, the mixture was placed in an ice bath and cooled to 0°C. Triethylamine (0.24 g) was then added, and the mixture was stirred at 0°C for about 15 min. While maintaining the system temperature at 0°C, compound 2 (1.70 g) was slowly added dropwise to the reaction system (the temperature was controlled at 0°C during the addition). After the addition was complete, the reaction was stirred at 0°C for 1.5 h. After the reaction was completed, saturated sodium bicarbonate solution (30 mL) was slowly added to quench the reaction, and the mixture was stirred for 10 min and allowed to stand for 15 min to separate the layers. The lower organic phase (dichloromethane layer) was collected. The organic phase was washed once with saturated brine (30 mL), allowed to stand for 15 min to separate the layers, and then collected. The organic phase was transferred to a dry conical flask, dried with activated anhydrous sodium sulfate for 30 min, filtered to remove the desiccant, and a clear organic phase was obtained. The organic phase was concentrated to dryness using a rotary evaporator at 35 °C and -0.09 MPa to obtain the crude product. The crude product was purified by silica gel column chromatography using a petroleum ether / ethyl acetate mixture as the eluent. The target fraction was collected and the solvent was removed to obtain intermediate 1, totaling 3.37 g. Mass spectrometry (MS+1) of intermediate 1: 517; : 8.53(s,1H),8.15(dd,1H),7.57(s,1H),7.43(s,1H),7.02-6.96(m,2H),6.94-6.78(m,2H),6.65-6.55(m,1H),3.88(d,6H); ; Compound 3: Phenylacetylene; Corrosion inhibitor 1: 4-(2-fluoro-4-(phenylethynyl)phenoxy)-6-methoxyquinazoline-7-yl 4-fluoro-2-methoxybenzoate; 3.37 g of intermediate 1 and 0.71 g of compound 3 were added to a four-necked flask. Under nitrogen protection, 80 mL of anhydrous tetrahydrofuran (THF) and 30 mL of triethylamine were added as a mixed solvent, and the mixture was stirred to ensure thorough dispersion. Subsequently, 0.37 g of cuprous iodide and 0.10 g of dichlorobis(triphenylphosphine)palladium were added as a co-catalyst system. The system was first cooled to 0 °C in an ice bath and stirred for 10 min. Then, the ice bath was removed and the temperature was raised to 60 °C, and the reaction was carried out at 60 °C with stirring for 6 h. After the reaction was completed, the mixture was cooled to room temperature, and 40 mL of saturated sodium bicarbonate solution was slowly added to quench the reaction. The stirring speed was adjusted to 400 rpm, and the mixture was stirred for 10 min. The mixture was then allowed to stand for 15 min to separate the layers. The organic phase was collected after separation. The organic phase was washed once with 40 mL of saturated brine, allowed to stand for separation, and then the organic phase was collected. The organic phase was transferred to a dry conical flask, and 4 g of activated anhydrous sodium sulfate was added for drying. The flask was sealed and allowed to stand for 30 min. The desiccant was removed by filtration, yielding a clear organic phase filtrate. The filtrate was transferred to a rotary evaporator and concentrated to dryness under reduced pressure at 35 °C and -0.09 MPa to obtain the crude product. The crude product was purified by silica gel column chromatography using a petroleum ether / ethyl acetate mixture as the eluent. The target fraction was collected, concentrated, and dried to obtain 2.76 g of corrosion inhibitor 1.

[0029] Mass spectrometry (MS+1): 539 for corrosion inhibitor 1; : 8.55(s,1H),8.12(dd,1H),7.59-7.50(m,3H),7.41-7.29(m,4H),7.12-7.02(m,2H),6.95-6.75(m,2H),6.67(dd,1H),3.87(d,6H).

[0030] Preparation Examples 2-5 In Preparation Examples 2-5, corrosion inhibitors 2 were prepared sequentially. The preparation method of the corrosion inhibitors was the same as in Preparation Example 1, except that compound 2 was replaced. The rest was the same as in Preparation Example 1. See Table 1 for details.

[0031] Table 1 Example 1

[0032] This embodiment provides a mass fraction of raw material components and its preparation method for a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating: 1. Raw material components by weight: Waterborne acrylic resin: glass transition temperature 15℃, solid content 48%, 38 parts; Nano titanium dioxide: particle size 5-10nm, hydrophobically modified, 3 parts, manufacturer: Changzhou Kenada New Material Technology Co., Ltd., model: KND-TW30G; Organosilane coupling agent: γ-aminopropyltriethoxysilane, 2 parts; Environmentally friendly film-forming aid: propylene glycol methyl ether acetate, VOC content 42g / L, 4 parts; Corrosion inhibitor: Corrosion inhibitor 1, prepared in preparation example 1, 2 parts; Defoamer: Silicone-based defoamer, 2 parts; Deionized water: 29 parts.

[0033] 2. Preparation method: S1: Pre-dispersion: First heat 29 parts of deionized water to... Then, heated deionized water and 2 parts of γ-aminopropyltriethoxysilane were added to the dispersion vessel, the stirring speed was adjusted to 400 r / min, and stirring was continued for 13 min. After thorough mixing, a uniform pre-dispersion was obtained. S2: Nanoparticle dispersion: Slowly add 3 parts of hydrophobic modified nano-titanium dioxide to the above pre-dispersion liquid, adjust the stirring speed to 1300 r / min, disperse at high speed for 25 min, start the ultrasonic dispersion device with power of 2000W and frequency of 30kHz, and perform ultrasonic dispersion treatment for 18 min. During the dispersion process, the system temperature is controlled to be maintained below 35℃ by the cooling device to avoid the high temperature affecting the dispersion stability of nanoparticles, and a stable and transparent nano-dispersion liquid is obtained. S3: Base material mixing: Add 38 parts of water-based acrylic resin dropwise to the above nano-dispersion at a rate of 1.5 parts / min, while maintaining a stirring speed of 900 r / min. During the addition process, continuously monitor the viscosity of the system using a rotational viscometer to ensure that the viscosity is maintained within the range of 800-1200 mPa·s. After the addition is complete, continue stirring for 20 min to fully integrate the water-based acrylic resin with the nano-dispersion and obtain a homogeneous and stable base material mixture. S4: Addition of functional additives: Nitrogen gas is introduced into the dispersion vessel to replace the internal air. Under the nitrogen atmosphere, 4 parts of environmentally friendly film-forming aid are added to the above base mixture. The mixture is stirred at 600 r / min for 5 min. Then, 2 parts of corrosion inhibitor and 2 parts of silicone defoamer are added at the same time. The stirring speed is adjusted to 700 r / min and stirred continuously for 20 min to ensure that the functional additives are evenly dispersed in the system, thus obtaining a preliminary anti-corrosion and environmentally friendly coating. S5: Filtration and Packaging: The preliminary anti-corrosion and environmentally friendly coating is pressure filtered through a 250-mesh filter to remove a small amount of incompletely dispersed particles and impurities in the system. After filtration, it is sealed and packaged to obtain the weather-resistant, transparent anti-corrosion and environmentally friendly coating.

[0034] 3. For example Figure 1As shown, the infrared spectra of Example 1 (with added corrosion inhibitor 1) and the control sample (without added corrosion inhibitor 1) have the same overall peak shape, both showing the characteristic absorption peak of C=O of the acrylic resin ester group (approximately). Aliphatic CH stretching vibration peak (approximately) and COC absorption peak (approximately Meanwhile, in Absorption bands dominated by Si-O-Si (silane hydrolysis / condensation products) and Si-OC related vibrations can be observed nearby. The presence of Ti-O-Ti absorption bands within the range indicates the presence of silane coupling agents and nanoparticles in the system. The component was effectively present in both groups of samples. Under the dispersion / ultrasonic conditions of step S2 of this invention, γ-aminopropyltriethoxysilane can undergo hydrolysis and react with... The hydroxyl groups on the surface undergo condensation, potentially forming a certain proportion of Si-O-Ti bonds at the interface; however, the infrared peak position in this region alone is insufficient to provide exclusive and quantitative confirmation of Si-O-Ti, therefore this specification describes it as "possible interfacial Si-O-Ti contribution." Compared to the control sample, Example 1... The nearby aromatic ring C=C absorption region exhibited a more pronounced absorption enhancement / shoulder peak change, indicating that the characteristic signal of the aromatic structure of the corrosion inhibitor 1 was superimposed on the coating system after its introduction; the above results are consistent with the formulation of Example 1 containing corrosion inhibitor 1 and nano- It is consistent with components such as γ-aminopropyltriethoxysilane.

[0035] 4. For example Figure 2 As shown, the coating in Example 1 exhibits a high transmittance plateau in the visible light region (approximately 400-800 nm), with a stable curve and transmittance close to 100%, consistent with the test result of a transparency of 98.5%. Simultaneously, in the ultraviolet region (approximately 320-380 nm), the transmittance shows a significant decrease, forming an "ultraviolet shielding" characteristic region, indicating that the nano-coating... It has a significant blocking effect on ultraviolet light, which helps to reduce the risk of photodegradation and yellowing of acrylic resin matrix by ultraviolet radiation and improve the weather resistance of coating; the spectral characteristics are consistent with the technical solution of adding hydrophobic modified nano titanium dioxide in Example 1. Examples 2-5

[0036] In Examples 2-5, a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating was prepared sequentially. The preparation method of Example 1 was followed, except that the corrosion inhibitors were replaced sequentially with corrosion inhibitors 2-5, while the rest remained the same as in Example 1.

[0037] Comparative Example 1 The preparation of a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating is carried out by referring to the preparation method of Example 1, except that the corrosion inhibitor is replaced with 2-mercaptobenzothiazole (a commonly used corrosion inhibitor), and the rest is the same as in Example 1.

[0038] Comparative Example 2 The preparation of a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating is carried out by referring to the preparation method of Example 1, except that the corrosion inhibitor is replaced with benzotriazole (a commonly used corrosion inhibitor), and the rest is the same as in Example 1.

[0039] Comparative Example 3 The preparation of a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating is the same as in Example 1, except that nano-titanium dioxide is not added.

[0040] Comparative Example 4 The preparation of a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating is the same as in Example 1, except that the organosilane coupling agent is not added.

[0041] Comparative Example 5 The preparation of a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating is carried out by referring to the preparation method of Example 1, except that the organosilane coupling agent is replaced with an aluminate coupling agent (selected from: isopropyl distearate aluminate), and the rest is the same as in Example 1.

[0042] Performance testing: 1. Transparency Test: The transparency was tested according to GB / T1721-2008 "Determination of Appearance and Transparency of Varnishes, Oils and Thinners". The coating was evenly applied to a clean glass plate, and the dry film thickness was controlled at 20±2μm. After curing under standard environmental conditions (temperature 23±2℃, relative humidity 50±5%) for 7 days, the transparency value of the coating was measured using a transparency meter and expressed as a percentage. The higher the transparency value, the better the transparency of the coating. The data are shown in Table 2.

[0043] 2. Accelerated UV Aging Test: The test was conducted using a xenon arc lamp aging chamber according to GB / T16422.2-2014 "Laboratory Light Source Exposure Test Methods for Plastics Part 2: Xenon Arc Lamp". The coated samples were placed inside the chamber, with the blackboard temperature controlled at 65±3℃, relative humidity at 50±10%, and irradiance at [value missing]. After continuous exposure for 1500 hours, the coatings were removed. The coatings were rated according to GB / T1766-2008 "Rating Method for Aging of Paint and Varnish Coatings", and aging phenomena such as chalking, discoloration, loss of gloss, and cracking were recorded. The color difference value ΔE before and after aging was measured using a colorimeter. The data are shown in Table 2.

[0044] 3. Neutral Salt Spray Test: The test was conducted according to GB / T1771-2007 "Determination of Neutral Salt Spray Resistance of Paints and Varnishes". The coating was applied to the surface of a sandblasted Q235 steel plate, with a dry film thickness controlled at 40±5 μm. After curing under standard environmental conditions for 7 days, it was placed in a salt spray test chamber. The test conditions were: sodium chloride solution concentration 50±5 g / L, pH value 6.5-7.2, test chamber temperature 35±2℃, and continuous spraying for 1500 h. Corrosion phenomena such as blistering, rusting, and peeling on the coating surface were observed and recorded periodically. The coating failure time and corrosion spread width were measured, and the data are shown in Table 2.

[0045] 4. Acid Resistance Test: The test was conducted according to GB / T9274-1988 "Determination of Resistance to Liquid Media by Paints and Varnishes". The coating was applied to the surface of a tinplate, with a dry film thickness controlled at 20±2 μm. After curing under standard environmental conditions for 7 days, two-thirds of the sample area was immersed in a 5% (mass fraction) sulfuric acid solution at 23±2℃ for 168 hours. The changes on the coating surface were observed, and the results were rated according to GB / T1766-2008. The data are shown in Table 2.

[0046] Table 2 A comparison of the data from Examples 1-5 and Comparative Examples 1-2 shows that the specific structure of the corrosion inhibitor synthesized in this invention is key to improving corrosion resistance. The corrosion inhibitor 1 used in Example 1 forms a stable chemical adsorption film on the metal surface through its nitrogen and oxygen heteroatoms and unsaturated bonds, resulting in no significant corrosion after 1500 hours of salt spray testing and achieving an acid resistance level of 0. In contrast, Comparative Examples 1 and 2 used ordinary corrosion inhibitors, but their long-term protective effect was still far inferior to that of Example 1. This verifies that the compound with the structure shown in Formula 1 can significantly reduce the activity of corrosive media and protect the substrate.

[0047] The main difference between Example 1 and Comparative Example 3 lies in the UV accelerated aging test. Comparative Example 3, without the addition of nano-titanium dioxide, although possessing extremely high initial transparency (due to the absence of particle scattering), showed a significant difference in color difference after 1500 hours of aging. The color difference reached a high of 6.80, resulting in severe yellowing. This indicates that nano-titanium dioxide played a crucial role in UV shielding within the system, protecting the acrylic resin matrix from photodegradation. Example 1 incorporated nano-titanium dioxide with a particle size of 10-50 nm, maintaining a high transparency of 98.5% while controlling the color difference to an extremely low level of 0.45, achieving a perfect balance between transparency and weather resistance.

[0048] Comparative Examples 4 and 5 focused on the effect of coupling agents. Comparative Example 4, without a coupling agent, resulted in poor interfacial bonding between inorganic particles and organic resin, a decrease in transparency to 91.5% (agglomeration leading to light scattering), and rapid blistering and peeling (failure after 300 hours) due to insufficient adhesion during salt spray and acid resistance tests. Comparative Example 5, using an aluminate coupling agent, performed better than without a coupling agent, but not as well as the γ-aminopropyltriethoxysilane in Example 1. This is because the amino functional groups of the silane coupling agent react better with the acrylic resin and substrate surface, improving not only dispersibility (high transparency) but also enhancing the density and wet adhesion of the coating, thereby significantly extending the corrosion protection life. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A weather-resistant, transparent, anti-corrosion, and environmentally friendly coating, characterized in that, By weight, its formula includes the following components: 30-45 parts of water-based acrylic resin, 2-5 parts of nano titanium dioxide, 1-3 parts of organosilane coupling agent, 3-6 parts of environmentally friendly film-forming aid, 1-4 parts of corrosion inhibitor, 1-3 parts of defoamer, and 20-35 parts of deionized water. The corrosion inhibitor is a compound represented by Formula 1; The structure of Equation 1 is as follows: ; The formula 1 It can be any one of halogen, methyl, cyano, trifluoromethyl, or nitro.

2. The weather-resistant, transparent, anti-corrosion, and environmentally friendly coating according to claim 1, characterized in that, The waterborne acrylic resin has a glass transition temperature of -10°C to 25°C and a solid content of 40%-55%.

3. The weather-resistant, transparent, anti-corrosion, and environmentally friendly coating according to claim 1, characterized in that, The particle size of the nano-titanium dioxide is 1-20 nm.

4. The weather-resistant, transparent, anti-corrosion, and environmentally friendly coating according to claim 1, characterized in that, The organosilane coupling agent is Aminopropyltriethoxysilane.

5. The weather-resistant, transparent, anti-corrosion, and environmentally friendly coating according to claim 1, characterized in that, The environmentally friendly film-forming aid is propylene glycol methyl ether acetate, and its VOC content is ≤50g / L.

6. The weather-resistant, transparent, anti-corrosion, and environmentally friendly coating according to claim 1, characterized in that, The corrosion inhibitor is any one of the compounds shown in the following structures: 。 7. The weather-resistant, transparent, anti-corrosion, and environmentally friendly coating according to claim 1, characterized in that, The defoamer is an organosilicon defoamer.

8. A method for preparing a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Pre-dispersion: Add the deionized water and organosilane coupling agent to a dispersion vessel, stir at 300-500 r / min for 10-15 min to obtain a pre-dispersion; S2. Nanoparticle dispersion: Add the nano-titanium dioxide to the pre-dispersion liquid, adjust the stirring speed to 1200-1500 r / min, disperse for 20-30 min, and then use ultrasonic dispersion treatment for 10-25 min to obtain nano-dispersion liquid; S3. Base material mixing: Add the aqueous acrylic resin to the nano-dispersion, maintain the stirring speed at 800-1000 r / min, and stir for 15-25 min to obtain the base material mixture; S4. Addition of functional additives: Under nitrogen protection, add the environmentally friendly film-forming aid to the base mixture, stir for 5 minutes, then add the corrosion inhibitor and defoamer, adjust the stirring speed to 600-800 r / min, stir for 15-30 minutes to obtain a preliminary anti-corrosion and environmentally friendly coating, filter to remove impurities and incompletely dispersed particles, and obtain the weather-resistant transparent anti-corrosion and environmentally friendly coating.

9. The method for preparing a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating according to claim 8, characterized in that, The ultrasonic dispersion in S2 has a power of 1500-2500W and a frequency of 20-40kHz, and the system temperature is controlled to not exceed 40℃ during the dispersion process.

10. The method for preparing a weather-resistant, transparent, anti-corrosion, and environmentally friendly coating according to claim 8, characterized in that, The addition rate of the water-based acrylic resin in S3 is 1-2 parts / min.

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