Antifouling, anti-fingerprint and corrosion-resistant stainless steel and preparation method thereof

Abstract

The preparation method comprises the following steps: step 1, preparing a heavy anti-corrosion primer which comprises organic silicon resin, high-temperature-resistant acrylic resin, a Ti3C2Tx MXene dispersion liquid, low-melting-point glass powder, high-temperature-resistant zinc powder and mesoporous silicon dioxide loaded with a benzotriazole corrosion inhibitor; step 2, preparing finishing paint: mixing acrylic resin, monohydroxyl-terminated polydimethylsiloxane PDMS, melamine, epoxy resin and an auxiliary agent according to a ratio to prepare a coating, and performing ultrasonic treatment to graft the PDMS onto the acrylic resin; and thirdly, after the stainless steel base material is pretreated, the base material is coated with primer and subjected to first-step curing, after surface light grinding treatment is conducted, finish paint is coated, second-step curing is conducted, and finally the stainless steel is obtained. Through a composite coating system and a stepped curing process, the double functions of long-acting corrosion prevention and lasting antifouling and fingerprint prevention are finally achieved on the stainless steel surface.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of stainless steel material preparation, and particularly relates to a stain-proof, fingerprint-proof and corrosion-resistant stainless steel and a preparation method thereof. BACKGROUND

[0002] Stainless steel is widely used in many fields such as construction, household appliances, chemical industry and ocean engineering due to its good mechanical strength and corrosion resistance. However, in a complex harsh environment with high humidity, high salinity or chemical medium, local corrosion such as pitting corrosion and crevice corrosion easily occurs on the surface of stainless steel, which affects its long-term service life and safety. Therefore, a heavy-duty coating is usually coated on the surface. The existing heavy-duty coating such as zinc-rich primer and epoxy coating can provide certain barrier and cathodic protection, but often faces problems such as thick coating, insufficient flexibility, limited high-temperature aging resistance and the like. In recent years, a new type of two-dimensional material MXene is introduced into the corrosion protection coating due to its excellent conductivity and shielding effect of the sheet layer, which can further improve the protection effect in cooperation with zinc powder, corrosion inhibitor and other components.

[0003] On the other hand, the surface of stainless steel and its coating is generally easy to be stained with grease, fingerprints and various pollutants, which seriously affects the appearance, and the corrosive components in the pollutants can penetrate and damage the coating, accelerating the corrosion of the substrate. Therefore, it is extremely important to endow the surface of stainless steel with stain-proof, fingerprint-proof and easy-to-clean functions. The existing surface functionalization technologies, such as constructing a fluorine-containing low-surface-energy coating or injecting liquid into a smooth porous surface, can effectively prevent stains, but often have technical problems such as complex process, environmental unfriendliness, poor adhesion to the underlying corrosion protection coating, and poor wear resistance. Especially, when the stain-proof topcoat is directly coated on the corrosion protection primer, the interlayer adhesion is weak due to the mismatch of the resin systems and curing temperature, and peeling easily occurs under mechanical or thermal stress.

[0004] In summary, the existing technology cannot achieve the dual functions of long-term heavy-duty corrosion protection and durable surface stain prevention on the surface of stainless steel. Either the single performance is focused at the expense of the other performance, or when trying to combine, the overall protection system fails early due to poor compatibility and weak interfacial bonding between the coatings. Therefore, it is a technical problem to be solved in the field to develop a composite coating system and a preparation method which can synergistically exert long-term corrosion protection and excellent stain-proof and fingerprint-proof functions, and finally obtain a stainless steel with long-term corrosion protection and surface cleaning dual functions. SUMMARY

[0005] This application provides a stain-resistant, fingerprint-resistant, and corrosion-resistant stainless steel and its preparation method, which solves the technical problem in the prior art that it is difficult to achieve the dual functions of long-term heavy corrosion protection and durable surface stain prevention on the stainless steel surface in an integrated manner. It realizes the construction of a high-performance composite coating on the stainless steel substrate with strong interlayer bonding and both intelligent corrosion protection and excellent surface cleaning properties.

[0006] This application provides a method for preparing anti-fouling, anti-fingerprint, and corrosion-resistant stainless steel, including the following steps:

[0007] Step 1: Preparing the primer

[0008] A heavy-duty anti-corrosion high-efficiency primer coating is prepared, wherein the heavy-duty anti-corrosion high-efficiency primer coating comprises organosilicon resin, high-temperature resistant acrylic resin, and Ti3C2T. X MXene dispersion, low melting point glass powder, high temperature resistant zinc powder, and mesoporous silica loaded with benzotriazole corrosion inhibitors;

[0009] Step 2: Prepare the topcoat

[0010] Prepare the following raw materials as needed: 35-45 parts acrylic resin, 1-3 parts monohydroxy-terminated polydimethylsiloxane PDMS, 5-8 parts melamine; 8-12 parts ethylene glycol monobutyl ether, 20-30 parts n-butanol, 3-5 parts epoxy resin, 0.5-1.5 parts silane coupling agent KH-560, 0.5-1 part dispersant, 0.2-1 part wetting agent, 0.1-0.3 parts leveling agent, and 0.3-1 part defoamer. Mix all components and mechanically stir at 25-30℃ for 30-60 minutes to prepare a coating. The molecular weight of polydimethylsiloxane PDMS is 1500-2000 Da.

[0011] The above raw materials are formulated into a transparent or semi-transparent coating. The prepared coating is then ultrasonically treated at 50-70°C for 1-3 hours to graft the low surface component monohydroxy-terminated polydimethylsiloxane (PDMS) in the coating onto the acrylic resin, thus obtaining a topcoat.

[0012] Step 3: Coating and Curing

[0013] First, the stainless steel substrate is cleaned and activated. Then, the primer obtained in step one is applied to the surface of the pretreated stainless steel substrate to form a primer layer, and the first-step curing is performed. After cooling to room temperature, the stainless steel surface is lightly polished, and then the topcoat obtained in step two is applied to the surface of the treated primer layer to form a topcoat layer, and the second-step curing is performed to finally obtain a stain-resistant, fingerprint-resistant, and corrosion-resistant stainless steel.

[0014] Preferably, in step one, the heavy-duty anti-corrosion high-efficiency primer coating comprises, by weight parts: 20-25 parts of silicone resin, 5-10 parts of high-temperature resistant acrylic resin, and Ti3C2T... x 5-10 parts of MXene dispersion, 10-15 parts of solvent, 0.5-1.5 parts of dispersant, 0.1-0.5 parts of defoamer, 0.5-1.5 parts of anti-settling agent, 5-10 parts of low melting point glass powder, 15-25 parts of high temperature resistant zinc powder, and 10-25 parts of mesoporous silica loaded with benzotriazole corrosion inhibitor.

[0015] Preferably, the mesoporous silica loaded with benzotriazole corrosion inhibitor in step one is prepared by vacuum impregnation of benzotriazole BTA into the pores of the mesoporous silica.

[0016] Preferably, the Ti3C2T in step one x The solid content of the MXene dispersion is 4-6%.

[0017] Preferably, the first step curing in step three is as follows: first, let it stand at room temperature for 10–15 minutes, and then cure it at 120–140°C for 20–30 minutes.

[0018] Preferably, the second-step curing in step three is as follows: first, maintain the temperature at 80–100°C for 10–15 minutes, then raise the temperature to 160–170°C and cure for 20–30 minutes.

[0019] This invention also provides a stain-resistant, fingerprint-resistant, and corrosion-resistant stainless steel prepared by any of the above-described methods.

[0020] One technical solution provided in this application embodiment has at least the following technical effects or advantages:

[0021] 1. By adopting a composite coating system that combines a heavy-duty anti-corrosion primer with synergistic effects of MXene, zinc powder and corrosion inhibitor mesoporous silica with a PDMS-grafted acrylic resin-based anti-fouling and anti-fingerprint topcoat, the technical problem of achieving both long-term corrosion protection and durable surface cleanliness on stainless steel surfaces has been effectively solved. This results in stainless steel products that combine excellent corrosion resistance with low surface energy and easy cleaning properties.

[0022] 2. Due to the introduction of mesoporous silica loaded with benzotriazole corrosion inhibitor into the primer, the material utilizes its abundant nanopores to store corrosion inhibitor molecules. When the coating is damaged, the intruding electrolyte can trigger the controlled release of BTA from the pores and form a protective adsorption film at the defects of the metal substrate, thereby realizing the coating's active repair function for micro-damage and significantly extending the effective protective life of the coating.

[0023] 3. Because fluorine-free PDMS is used as a low surface energy component in the topcoat and grafted directly into commercially available resins through an ultrasonic-assisted process, there is no need to pre-synthesize complex copolymers or perform special pretreatment on the primer layer. This effectively solves the technical problems of complex processes and reliance on fluorine-containing substances in existing antifouling technologies, thereby simplifying the topcoat preparation and coating process, reducing costs and environmental burden, while ensuring excellent antifouling, anti-fingerprint performance and high transparency of the coating. Attached Figure Description

[0024] Figure 1 This is a flowchart of the preparation process in Embodiment 1 of this application. Detailed Implementation

[0025] This application provides a stain-resistant, fingerprint-resistant, and corrosion-resistant stainless steel and its preparation method, aiming to solve the dual problems of stainless steel's susceptibility to corrosion in harsh environments and its easy adhesion to stains and fingerprints. Therefore, the core of this embodiment lies in obtaining a stainless steel that achieves both long-term corrosion resistance and surface cleaning through a composite coating system that utilizes synergistic component composition, interface optimization, and process matching.

[0026] The technical solution in this application is to solve the above problems, and the overall approach is as follows:

[0027] First, a heavy-duty anti-corrosion primer integrating MXene physical barrier, zinc powder cathodic protection, and mesoporous silica-loaded corrosion inhibitor is prepared. This primer forms a dense and electrochemically active protective underlayer through medium-temperature curing. Second, an anti-fouling and anti-fingerprint topcoat is prepared by ultrasonically grafting PDMS onto acrylic resin. Most importantly, by lightly grinding the surface after primer curing and employing a stepped curing process that matches the reaction characteristics of the primer and topcoat resin systems, a strong interfacial bonding layer is constructed between the primer and topcoat. This firmly combines the "active + passive" long-term anti-corrosion capability of the primer with the low surface energy characteristics of the topcoat, ultimately obtaining a high-performance, durable, anti-fouling, anti-fingerprint, and corrosion-resistant stainless steel product.

[0028] To better understand the above technical solutions, the implementation methods of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The following embodiments are intended to further illustrate the present invention, but not to limit the scope of protection of the present invention.

[0029] Example 1

[0030] (1) Preparation method of primer

[0031] The heavy-duty anti-corrosion high-efficiency primer coating comprises the following raw materials in parts by weight:

[0032] 20-25 parts silicone resin, 5-10 parts high-temperature resistant acrylic resin, Ti3C2T XMXene dispersion (5% solids) 5-10 parts, solvent 10-15 parts, dispersant 0.5-1.5 parts, defoamer 0.1-0.5 parts, anti-settling agent 0.5-1.5 parts, low melting point glass powder 5-10 parts, high temperature resistant zinc powder 15-25 parts, mesoporous silica loaded with benzotriazole corrosion inhibitor 10-25 parts;

[0033] First, epoxy-modified silicone resin and methylphenyl silicone resin are mixed at a mass ratio of 1:4 to obtain silicone resin; Qizhan resin C10 is selected as the high-temperature resistant acrylic resin; a mixture of xylene and n-butanol is selected as the solvent, with xylene:n-butanol = 60:40; BYK-163 is selected as the dispersant; TEGO-900 is selected as the defoamer; a mixture of silica and polyamide wax paste is selected as the anti-settling agent, with a mass ratio of 1:1; 1140 low-melting-point glass powder is selected as the low-melting-point glass powder; and Shenlong 800 mesh high-temperature resistant zinc powder is selected as the high-temperature resistant zinc powder.

[0034] First, mix the silicone resin, solvent, and dispersant, and stir at a low speed; then, add Ti3C2T sequentially at a medium speed. x The primer is prepared by high-speed dispersion of MXene, high-temperature zinc powder, mesoporous silica loaded with benzotriazole corrosion inhibitor and low-melting-point glass powder until the fineness meets the requirements, and then adding defoamer and anti-settling agent to adjust the viscosity.

[0035] (1.1) The preparation of mesoporous silica supported on benzotriazole corrosion inhibitors is as follows:

[0036] Step 1: Dissolve hexadecyltrimethylammonium bromide (CTAB) in a three-necked flask containing a mixture of deionized water and anhydrous ethanol. Maintain a constant temperature in a 40°C water bath with stirring at 300 rpm. Slowly add ammonia water dropwise to the clarified solution, stirring for 30 minutes to create a homogeneous alkaline environment. Then, within 1 hour, slowly add tetraethyl orthosilicate (TEOS) dropwise using a constant-pressure dropping funnel. After the addition is complete, continue the reaction at 40°C for 6 hours. After the reaction is complete, centrifuge the resulting white suspension at 8000 rpm for 10 minutes, washing three times alternately with deionized water and ethanol to remove excess ammonia water and template agent. Dry the resulting white precipitate in a vacuum drying oven at 60°C for 12 hours. Finally, place the dried powder in a muffle furnace and calcine at 550°C for 6 hours at a heating rate of 1°C / min to completely remove the CTAB template agent, obtaining a white silica powder with a rich mesoporous structure.

[0037] Step 2: Dissolve 800 mg of benzotriazole BTA completely in 50 mL of anhydrous ethanol to form a saturated ethanol solution of benzotriazole BTA. Slowly add 1.0 g of mesoporous silica powder to the above benzotriazole BTA solution and sonicate at room temperature for 30 minutes to ensure that the silica is fully dispersed and wetted. Transfer the mixture to a rotary evaporator and perform vacuum impregnation under a 40°C water bath and low-speed rotation. This step aims to use vacuum conditions to remove air from the channels and use capillary force to fully fill the mesoporous channels with BTA solution. After impregnation for 2 hours, stop rotary evaporation and allow the resulting slurry to stand at 40°C for 12 hours. Finally, filter the loaded slurry and wash the physically adsorbed benzotriazole BTA on the filter cake surface with a small amount of ethanol. Vacuum dry the filter cake at 50°C for 24 hours to obtain the final product—mesoporous silica loaded with benzotriazole corrosion inhibitors.

[0038] In the preparation scheme of the primer in this embodiment, Ti3C2T x The introduction of MXene dispersion utilizes its two-dimensional lamellar structure arranged parallel within the coating, effectively extending the penetration path of corrosive media and forming an excellent physical barrier effect. In addition to providing traditional sacrificial anode cathodic protection, the high-temperature resistant zinc powder, together with the MXene lamellars, can form a conductive network that more uniformly and efficiently transmits protective current, enhancing cathodic protection efficiency. Mesoporous silica loaded with benzotriazole BTA corrosion inhibitor serves as an intelligent corrosion inhibition unit; its mesoporous structure can efficiently adsorb and store BTA molecules. When the coating develops micro-defects due to scratches or other reasons, the infiltrated moisture triggers the controlled release of BTA from the pores, which is then adsorbed at the metal defect site to form a protective film, thereby inhibiting further corrosion expansion and achieving active self-repair. Low-melting-point glass powder softens and flows at the curing temperature, helping to fill the micropores of the coating and improving its density and temperature resistance.

[0039] (2) Preparation method of topcoat

[0040] ① Raw material preparation: Weigh the following raw materials: 35-45 parts acrylic resin, 1-3 parts monohydroxy-terminated polydimethylsiloxane PDMS (PDMS molecular weight is 1500-2000 Da), 5-8 parts melamine; 8-12 parts ethylene glycol monobutyl ether, 20-30 parts n-butanol, 3-5 parts epoxy resin, 0.5-1.5 parts silane coupling agent KH-560, 0.5g dispersant, 0.2g wetting agent, 0.3g leveling agent, and 1g defoamer. Ensure the environment is dry and clean to avoid the introduction of impurities.

[0041] ② Coating Preparation: Add acrylic resin, PDMS, melamine, ethylene glycol monobutyl ether, n-butanol, and epoxy resin sequentially to a mixing container. Mechanically stir at 300-500 rpm for 30-60 minutes at 25-30℃ until a homogeneous mixture is formed. Then, premix silane coupling agent KH-560 with 1-2 parts deionized water and 5 parts ethanol, hydrolyze and age for 10-20 minutes, and slowly add this mixture to the above mixture, continuing to stir for 20 minutes. Next, add dispersant, wetting agent, leveling agent, and defoamer, and continue stirring for 10-15 minutes to obtain a transparent or translucent coating.

[0042] S02 PDMS grafting pre-reaction

[0043] The above mixture was subjected to ultrasonic treatment at 60°C and 100W for 1 hour to obtain an anti-fouling and anti-fingerprint coating, i.e., the topcoat. The purpose of this step is to enable the siloxane bonds of PDMS to undergo a grafting reaction with the hydroxyl or carboxyl groups of acrylic resin, generating a stable copolymer structure, thereby reducing the surface energy of the coating. The reaction progress can be monitored by FTIR infrared spectroscopy to detect the formation of Si-OC bonds, with a characteristic peak at approximately 1100 cm⁻¹. During the subsequent curing process, the grafted PDMS segments, due to their low surface energy, will spontaneously migrate to and accumulate at the coating / air interface, thus forming a durable and stable low surface energy layer on the coating surface.

[0044] (3) Coating and curing

[0045] (3.1) Substrate pretreatment

[0046] Solvents such as acetone or ethanol are used to remove oil stains from stainless steel substrates, followed by mechanical polishing or chemical passivation to improve surface roughness and activity, ensuring primer adhesion.

[0047] (3.2) Primer application and curing

[0048] High-pressure airless spraying or dip coating is used to control the wet film thickness to 80–120 μm. Step curing is performed by first letting the film stand at room temperature for 10–15 minutes to allow partial evaporation of the solvent, and then curing at 120–140℃ for 20–30 minutes.

[0049] After the primer has fully cured, it is cooled to room temperature. The surface is then lightly sanded to remove surface dust, which enhances interlayer adhesion and provides more reaction sites for the silane coupling agent KH-560 in the topcoat, mainly enhancing the mechanical interlocking effect.

[0050] (3.3) Topcoat application and curing

[0051] The topcoat is applied by spraying to ensure a uniform and smooth surface, and the wet film thickness is controlled at 30–50 μm.

[0052] In another embodiment, 1–2% of an adhesion promoter may be added to the topcoat to enhance bonding.

[0053] First, maintain the temperature at 80–100℃ for 10–15 minutes to allow the solvent to evaporate slowly and avoid bubbles. At the same time, KH-560 will couple with the primer surface. Then, raise the temperature to 160–170℃ and cure for 20–30 minutes to allow the melamine to fully crosslink and the PDMS to complete surface enrichment, forming a low surface energy antifouling layer.

[0054] In one embodiment, after curing is complete, slow cooling can be used to reduce internal stress, such as a cooling rate ≤2℃ / min.

[0055] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0056] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a stain-resistant, fingerprint-resistant, and corrosion-resistant stainless steel, characterized in that, Includes the following steps: Step 1: Preparing the primer A heavy-duty anti-corrosion high-efficiency primer coating is prepared, wherein the heavy-duty anti-corrosion high-efficiency primer coating comprises organosilicon resin, high-temperature resistant acrylic resin, and Ti3C2T. x MXene dispersion, low melting point glass powder, high temperature resistant zinc powder, and mesoporous silica loaded with benzotriazole corrosion inhibitors; Step 2: Prepare the topcoat Prepare the following raw materials as needed: 35-45 parts acrylic resin, 1-3 parts monohydroxy-terminated polydimethylsiloxane PDMS, 5-8 parts melamine; 8-12 parts ethylene glycol monobutyl ether, 20-30 parts n-butanol, 3-5 parts epoxy resin, 0.5-1.5 parts silane coupling agent KH-560, 0.5-1 part dispersant, 0.2-1 part wetting agent, 0.1-0.3 parts leveling agent, and 0.3-1 part defoamer. Mix all components and mechanically stir at 25-30℃ for 30-60 minutes to prepare a coating. The molecular weight of polydimethylsiloxane PDMS is 1500-2000 Da. The above raw materials are formulated into a transparent or semi-transparent coating. The prepared coating is then ultrasonically treated at 50-70°C for 1-3 hours to graft the low surface component monohydroxy-terminated polydimethylsiloxane (PDMS) in the coating onto the acrylic resin, thus obtaining a topcoat. Step 3: Coating and Curing First, the stainless steel substrate is cleaned and activated. Then, the primer obtained in step one is applied to the surface of the pretreated stainless steel substrate to form a primer layer, and the first-step curing is performed. After cooling to room temperature, the stainless steel surface is lightly polished, and then the topcoat obtained in step two is applied to the surface of the treated primer layer to form a topcoat layer, and the second-step curing is performed to finally obtain a stain-resistant, fingerprint-resistant, and corrosion-resistant stainless steel.

2. The method for preparing the anti-fouling, anti-fingerprint, and corrosion-resistant stainless steel according to claim 1, characterized in that, In step one, the heavy-duty anti-corrosion high-efficiency primer coating comprises, by weight parts: 20-25 parts of silicone resin, 5-10 parts of high-temperature resistant acrylic resin, and Ti3C2T. x 5-10 parts of MXene dispersion, 10-15 parts of solvent, 0.5-1.5 parts of dispersant, 0.1-0.5 parts of defoamer, 0.5-1.5 parts of anti-settling agent, 5-10 parts of low melting point glass powder, 15-25 parts of high temperature resistant zinc powder, and 10-25 parts of mesoporous silica loaded with benzotriazole corrosion inhibitor.

3. The method for preparing the anti-fouling, anti-fingerprint, and corrosion-resistant stainless steel according to claim 1, characterized in that, The mesoporous silica loaded with benzotriazole corrosion inhibitor in step one is prepared by vacuum impregnation, in which benzotriazole BTA is loaded into the pores of the mesoporous silica.

4. The method for preparing the anti-fouling, anti-fingerprint, and corrosion-resistant stainless steel according to claim 1, characterized in that, The first step of curing in step three is as follows: first, let it stand at room temperature for 10–15 minutes, and then cure it at 120–140℃ for 20–30 minutes.

5. The method for preparing the anti-fouling, anti-fingerprint, and corrosion-resistant stainless steel according to claim 1, characterized in that, The second-step curing in step three is as follows: first, maintain the temperature at 80–100℃ for 10–15 minutes, then raise the temperature to 160–170℃ and cure for 20–30 minutes.

6. The method for preparing the anti-fouling, anti-fingerprint, and corrosion-resistant stainless steel according to claim 1, characterized in that, The Ti3C2T in step one x The solid content of the MXene dispersion is 4-6%.

7. A stain-resistant, fingerprint-resistant, and corrosion-resistant stainless steel prepared by any one of claims 1 to 6.

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