A tough inorganic heavy-duty coating and its method of preparation and use

Abstract

The present application relates to a kind of heavy-duty coating with good toughness, especially to a kind of heavy-duty coating with good toughness with high-temperature resistant, fireproof, flame-retardant performance on surface, especially suitable for the corrosion protection of non-planar substrate in chemical industry under high temperature.The present application discloses a kind of inorganic heavy-duty coating with good toughness, including heavy-duty primer, anti-permeation toughening midcoat and high-temperature resistant fireproof topcoat from base layer outward.The present application can obtain the following technical effects by using coating with specific composition:the coating has good flame retardance, 1100℃ combustion test, no expansion, cracking, perforation, burning within 60 minutes.The temperature resistance performance is long-term 400℃ to 500℃, instantaneous 550℃ thermal shock.The toughness is good, impact resistance performance parameter is high, corrosion resistance is good, sample surface is free from rust after 1500 hours;Environmentally friendly, VOC emission is low;Construction cycle is short.

Description

Technical Field

[0001] This invention relates to the field of corrosion protection, specifically to a tough inorganic heavy-duty anti-corrosion coating, its preparation method, and its applications. In particular, it relates to a heavy-duty anti-corrosion coating with high-temperature resistance, fire resistance, and flame retardant properties, which is especially suitable for corrosion protection of non-planar substrates in the chemical industry at high temperatures. Background Technology

[0002] Heavy-duty anti-corrosion coatings are high-performance protective coatings specifically designed for severely corrosive environments. Their core objective is to significantly extend the service life of substrates such as metals and concrete under harsh conditions through a long-lasting, multi-layered, and robust protective system. Heavy-duty anti-corrosion coatings need to withstand complex environments with multiple corrosive factors, including high humidity, strong acids / alkalis, salt spray, high temperatures, ultraviolet radiation, and mechanical wear. Applications include heavy-duty anti-corrosion coatings for marine engineering and chemical facilities. The design protection period for heavy-duty anti-corrosion coatings is typically over 10 years, with high-end systems such as fluorocarbon and polysiloxane coatings reaching 20-30 years under ideal conditions, far exceeding that of ordinary anti-corrosion coatings. Through mechanisms such as dense shielding, electrochemical protection, and synergistic effects of corrosion inhibitors, they significantly reduce the corrosion rate of the substrate.

[0003] A typical heavy-duty anti-corrosion coating system includes a primer, intermediate coat, and topcoat. The primer primarily serves to prevent corrosion, the intermediate coat is used for thickening and impermeability, and the topcoat provides weather protection. Each layer complements and works synergistically. Depending on the specific requirements, functional fillers that can be used in each layer include zinc powder (a sacrificial anode) and mica iron oxide (enhancing corrosion shielding).

[0004] Epoxy resin coatings offer strong adhesion and chemical resistance, making them widely used on offshore platforms and ships. Polyurethane coatings boast excellent weather resistance and UV resistance, commonly used as topcoats for outdoor structures such as bridges and wind turbine towers. Fluorocarbon resin coatings possess ultra-high weather resistance and self-cleaning properties, suitable for high-end applications such as landmark buildings and cross-sea bridges. Acrylic coatings are fast-drying and environmentally friendly, suitable for protecting industrial equipment in mildly corrosive environments. Polysiloxane coatings combine weather resistance and chemical resistance, serving as a replacement for traditional polyurethane / epoxy systems in oil platforms and chemical plants. However, many of these traditional polymer coatings rely heavily on organic solvents as dispersion media, making them unable to meet increasingly stringent environmental regulations. While waterborne polymer coatings have been developed for decades, they are more expensive than solvent-based polymer coatings, dry slowly, require long multi-layer coating cycles, consume high energy for auxiliary drying and curing, and, more importantly, have insufficient temperature resistance.

[0005] Inorganic silicate coatings protect the substrate with zinc powder sacrificial anodes, exhibiting good high-temperature resistance, capable of withstanding temperatures above 400°C, making them suitable for corrosion protection in the high-temperature chemical industry. However, inorganic silicate coatings suffer from insufficient toughness and high brittleness when used on non-planar substrates such as high-temperature chemical pipelines and valves, leading to easy cracking. While multi-layered, multi-system organic-inorganic coatings can address the lack of toughness, they can introduce various problems such as insufficient heat resistance, VOC emissions, poor adhesion, or insufficient corrosion protection with thick coatings.

[0006] Existing technology CN202211533354.3 discloses a fire-resistant, high-temperature resistant, heavy-duty anti-corrosion coating and its preparation method, including a heavy-duty anti-corrosion zinc-aluminum primer and a fire-resistant, high-temperature resistant coating. The heavy-duty anti-corrosion zinc-aluminum primer is applied to the surface of a substrate, and the fire-resistant, high-temperature resistant coating is applied to the surface of the heavy-duty anti-corrosion zinc-aluminum primer. The components of the heavy-duty anti-corrosion zinc-aluminum primer include a silicon-based binder, zinc powder, aluminum powder, and a rust-inhibiting penetrant. The components of the fire-resistant, high-temperature resistant coating include a silicon-based binder, titanium dioxide, and silicon carbide. However, it is not suitable for the corrosion protection of non-planar substrates at high temperatures in the chemical industry, and its performance is insufficient to meet current requirements.

[0007] Therefore, developing inorganic silicate heavy-duty anti-corrosion coatings for non-planar substrates has become an important means to solve the corrosion protection problem of high-temperature chemical pipelines, valves, etc. Summary of the Invention

[0008] To address the aforementioned problems, the present invention aims to provide a heavy-duty anti-corrosion coating with high-temperature resistance, fire resistance, flame retardancy, and good toughness, suitable for corrosion protection of non-planar substrates in the chemical industry at high temperatures. The present invention also aims to provide a method for preparing a heavy-duty anti-corrosion coating with high-temperature resistance, fire resistance, flame retardancy, and good toughness for use on the surface of non-planar substrates in the chemical industry.

[0009] A tough inorganic heavy-duty anti-corrosion coating comprises, from the base layer outwards, a heavy-duty anti-corrosion base layer, an anti-permeability and toughening intermediate layer, and a high-temperature and fire-resistant topcoat. The anti-permeability and toughening intermediate layer is formed by applying an intermediate coating onto the heavy-duty anti-corrosion base layer. The intermediate coating includes a silicone-based binder B, an anti-permeability agent, a stabilizer, and a diluent. The silicone-based binder B is composed of potassium silicate, ethylene glycol, and a toughening crosslinking agent in a mass ratio of 10-30:5-10:15-25.

[0010] Furthermore, the intermediate coating consists of a silicone-based binder B, an anti-permeability agent, a stabilizer, and a diluent in a mass ratio of 2-4:1-2:0.5-1:20-40; the toughening crosslinking agent consists of CO-C4 alkyl dialkyl diekoxysilane, C8-C18 alkyl alkyl trialkoxysilane, and CO-C4 alkoxy tetraalkoxysilane in a molar ratio of 3-5:2-3:1-2, where CO alkyl refers to H replacing alkyl and being directly connected to Si.

[0011] Furthermore, the C0-C4 alkyl dialkyldialkoxysilane is selected from one or more of dimethoxysilane, diethoxysilane, methyldimethoxysilane, ethyldiethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, dimethyldiethoxysilane, and diethyldimethoxysilane.

[0012] The tetraalkoxysilane with C0-C4 alkoxy groups is preferably one or more of tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetran-butoxysilane, and tetraisobutoxysilane.

[0013] Furthermore, the C8-C18 alkyl alkyltrialkoxysilane is selected from one or more of octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, tetradecyltrimethoxysilane, tetradecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, and octadecyltriethoxysilane.

[0014] Furthermore, the heavy-duty anti-corrosion primer is formed by applying a primer coating to the surface of the substrate. The primer coating includes a silicone-based binder, zinc powder, aluminum powder, anti-penetration agent, stabilizer, and diluent. The silicone-based binder A is composed of potassium silicate or sodium silicate, potassium methylsilicate, and aluminum oxide in a mass ratio of 10-30:5-15:5-10.

[0015] Furthermore, the high-temperature fireproof topcoat is formed by coating a topcoat onto an anti-permeability and toughening intermediate coating. The topcoat consists of a silicon-based binder C, titanium dioxide, silicon carbide, stabilizer, and diluent in a mass ratio of 1-2:2-3:2-3:1-2:20-30. The silicon-based binder C consists of potassium silicate and fumed silica in a mass ratio of 10-30:5-10.

[0016] Furthermore, the primer coating consists of a silicone-based binder A, zinc powder, aluminum powder, an anti-permeability agent, a stabilizer, and a diluent in a mass ratio of 2-4:1-2:1-3:0.5-1:0.5-1:20-50.

[0017] Furthermore, the topcoat is composed of a silicon-based binder C, titanium dioxide, silicon carbide, stabilizer, and diluent in a mass ratio of 1-2:2-3:2-3:1-2:20-30.

[0018] Furthermore, the stabilizer is silicate stabilizer GSYWDJ-5; the diluent is a mixed solution of deionized water and anhydrous ethanol in a volume ratio of 3-5:3-5; the modulus of the potassium silicate is 1.5-3.5; and the modulus of the sodium silicate is 1.5-3.5.

[0019] Potassium silicate, also known as potassium silicate glass, is an inorganic silicate. The modulus of potassium silicate refers to the molar ratio of SiO2 to K2O, usually expressed as nK, i.e., nK = SiO2 / K2O. The modulus affects the performance of coatings; different moduli influence properties such as viscosity, adhesion, durability, and permeability. The potassium silicate used in this invention has an nK between 1.5 and 3.5. When the modulus is too low (nK < 1.5), the potassium silicate solution has low viscosity and is easy to apply, but its durability is poor, making it only suitable for applications with low performance requirements. Furthermore, when the potassium silicate modulus nK in the intermediate coating is < 1.5, the crosslinking reaction between potassium silicate and the toughening crosslinking agent is slow and the degree of crosslinking is low, resulting in a toughened intermediate coating with good flexibility but insufficient hardness and strength. When the modulus is moderate (1.5 ≤ nK ≤ 3.5), the potassium silicate solution has moderate viscosity and good adhesion and durability. When the modulus is too high (nK > 3.5), the potassium silicate solution has higher viscosity and stronger adhesion, but the application difficulty increases, making it suitable for applications requiring extremely high adhesion. Furthermore, when the potassium silicate modulus nK in the intermediate coating is > 3.5, the crosslinking reaction between potassium silicate and the toughening crosslinking agent is slow and the degree of crosslinking is low, resulting in insufficient toughness in the formed anti-permeability toughening intermediate coating. In practical applications, based on balancing the workability and performance requirements of the coating, common potassium silicate coating products used, such as Krauthamer's KSilan 280 and KSilan 320, have moduli of 2.8 and 3.2, respectively.

[0020] Therefore, the potassium silicate modulus nK of the present invention is selected to be 1.5-3.5, preferably nK=1.8-3.2, and more preferably nK=2-3. The value of nK is not particularly limited and is selected according to the commercially available products. Specifically, nK is selected as 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, etc., which will not be elaborated here.

[0021] Sodium silicate, also known as sodium silicate water glass, is commonly referred to as water glass. Sodium silicate and potassium silicate are the most commonly used silicate binders. The modulus of sodium silicate is the molar ratio of SiO2 to Na2O, nNa = SiO2 / Na2O. The sodium silicate used in this invention has an nNa value between 1.5 and 3.5. At a low modulus (n < 1.5), it exhibits good water solubility, low viscosity, and ease of application, but poor durability and water resistance, making it suitable only for applications with low performance requirements, such as temporary protective coatings. Furthermore, when the potassium silicate modulus nK in the intermediate coating is < 1.5, the crosslinking reaction between potassium silicate and the toughening crosslinking agent is slow and the degree of crosslinking is low, resulting in a toughening intermediate coating with good flexibility but insufficient hardness and strength. When the modulus is medium (1.5-3.5), the viscosity is moderate, with good adhesion and durability, making it suitable for fire-retardant coatings and industrial anti-corrosion coatings. When the modulus is too high (n > 3.5), the viscosity is high, the adhesion is strong, and the durability and weather resistance are excellent, but the construction difficulty increases, and the cross-linking reaction between sodium silicate and toughening cross-linking agent is slow and the degree of cross-linking is low, resulting in insufficient toughness of the anti-permeability toughening intermediate coating.

[0022] Therefore, the potassium silicate modulus nNa of this invention is selected to be 1.5-3.5, preferably nNa=1.8-3.3, and more preferably nNa=2-3. The value of nNa is not specifically limited and is selected according to the commercially available products. Specifically, nNa is selected as 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, etc., which will not be elaborated here.

[0023] Potassium silicate aqueous solution is strongly alkaline, which can promote the hydrolysis reaction of alkoxysilanes such as tetraethyl orthosilicate, and potassium silicate and tetraethyl orthosilicate hydrolyze and crosslink with each other. The ethanol produced by the hydrolysis and condensation reaction of tetraethyl orthosilicate evaporates together with the dispersion medium, accelerating the drying speed of the coating. Ethylene glycol, as a stabilizer for the hydrolysis and crosslinking reaction of potassium silicate and tetraethyl orthosilicate, is used to control the hydrolysis reaction rate and avoid excessively rapid gelation to form three-dimensional condensation polymers, which would cause toughening failure.

[0024] Based on this reaction mechanism, the present invention sets up a toughening crosslinking agent consisting of C0-C4 alkyl dialkyldialkoxysilane, C8-C18 alkyl alkyltrialkoxysilane, and C0-C4 alkoxy tetraalkoxysilane. The alkylalkoxysilane, tetraalkoxysilane, and potassium silicate are co-hydrolyzed, crosslinked, and condensed to obtain a non-completely shaped condensation polymer. The -O-R1SiR2-O-R1SiR2-O- in the molecular structure can rotate and vibrate, appropriately reducing the rigidity of the molecular chain structure, thereby reducing the brittleness of the coating and improving the overall toughness of the coating.

[0025] For example, tetraethyl orthosilicate Si(OCH2CH3)4, ethyltriethoxysilane CH3CH2Si(OCH2CH3)3, and diethyldiethoxysilane (CH3CH2)2Si(OCH2CH3)2 are hydrolyzed, crosslinked, and polycondensed with potassium silicate K2SiO3. Ethylene glycol is added to adjust the hydrolysis reaction rate, avoid the sol from gelling too quickly, promote the adhesion of the intermediate coating to the base coating and top coating, and increase the overall toughness of the coating.

[0026] C0-C4 alkyl dialkyldialkoxysilanes primarily function to reduce the degree of crosslinking and increase flexibility in toughening crosslinking agents. Difunctional dialkyldialkoxysilanes are mainly used to form rotatable and vibratory -O-R1SiR2-O-R1SiR2-O- structures. Compared to tetrafunctional tetraalkoxysilanes, which form fully three-dimensional condensation polymers, they increase the number of long and short chain structures in the molecular structure to form incomplete three-dimensional structures, thereby appropriately reducing the rigidity of the condensation polymer and increasing its toughness.

[0027] Preferably, the C0-C4 alkyl dialkyldialkoxysilane is selected from one or more of dimethoxysilane, diethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, dimethyldiethoxysilane, and diethyldimethoxysilane. More preferably, the dialkyldialkoxysilane is selected from dimethoxysilane, diethoxysilane, dimethyldimethoxysilane, and diethyldiethoxysilane; most preferably, the dialkyldialkoxysilane is selected from diethoxysilane and / or diethyldiethoxysilane.

[0028] C8-C18 alkyl alkyltrialkoxysilanes play a role in crosslinking and increasing flexibility in toughening crosslinking agents. Trifunctional alkyltrialkoxysilanes can increase the degree of crosslinking compared to difunctional dialkyldialkoxysilanes. Substituent C8-C18 alkyl groups, as flexible long chains, can increase the flexibility of the molecular structure. In addition, C8-C18 alkyl groups have strong hydrophobicity, which promotes the migration of crosslinking molecules to the coating interface in hydrophilic silane condensates, thereby enhancing the chemical crosslinking and toughness at the coating interface.

[0029] Preferably, the C8-C18 alkyl alkyltrialkoxysilane is selected from one or more of octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, tetradecyltrimethoxysilane, tetradecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, and octadecyltriethoxysilane. More preferably, the C8-C18 alkyl alkyltrialkoxysilane is selected from octyltriethoxysilane, decyltriethoxysilane, dodecyltriethoxysilane, tetradecyltriethoxysilane, hexadecyltriethoxysilane, and octadecyltriethoxysilane. Most preferably, the C8-C18 alkyl alkyltrialkoxysilane is selected from octyltriethoxysilane and / or decyltriethoxysilane.

[0030] The C8-C18 alkyl substituents mentioned above can be unbranched n-alkane groups or isoalkane groups with certain branches. If the number of carbons in the alkyl substituent is less than 8, its hydrophobicity and flexibility will be reduced, affecting the toughening effect of the intermediate coating and the interfacial chemical crosslinking effect; if the number of carbons in the alkyl substituent is greater than 18, its hydrophobicity and flexibility gain is not significant, but it will significantly increase the cost.

[0031] Tetraalkoxysilanes, such as tetramethoxysilane (methyl orthosilicate TMOS) and tetraethoxysilane (ethyl orthosilicate TEOS), are the most common unsubstituted siloxanes. When tetraalkoxysilanes are hydrolyzed, the alkoxy groups are gradually replaced by hydroxyl groups to produce silicic acid and alcohol.

[0032] Preferably, the CO-C4 alkoxy tetraalkoxysilane is selected from one or more of tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, and tetrabutoxysilane. More preferably, the CO-C4 alkoxy tetraalkoxysilane is selected from tetran-butoxysilane.

[0033] The molar ratio of toughening and crosslinking agents C0-C4 alkyl dialkyl diekoxysilane, C8-C18 alkyl alkyl trialkoxysilane, and C0-C4 alkoxy tetraalkoxysilane is 3-5:2-3:1-2.

[0034] The above-mentioned method for preparing heavy-duty anti-corrosion coating includes four steps:

[0035] The first step is to prepare the primer, intermediate coat, and top coat separately.

[0036] Preparation of primer coating: First, weigh each component in the formula using a weighing device. Then, add the diluent, potassium silicate, and potassium methylsilicate to the coating mixing equipment and mix at 500-1000 rpm for 0.5-1 hour. Next, add fumed silica and mix at 500-1000 rpm for 0.5-1 hour. Finally, add zinc powder, aluminum powder, anti-penetration agent, and stabilizer to the coating mixing equipment in sequence and mix at 500-1000 rpm for 0.5-1 hour to obtain the primer coating for later use.

[0037] The primer coating is packaged separately and can be used as a primer for the heavy-duty anti-corrosion coating of this invention, or as an anti-corrosion coating on its own.

[0038] Preparation of intermediate coating: First, weigh each component in the formula using a weighing device. Then, add the anti-penetration agent, stabilizer, and diluent together to a coating mixing device and mix at 500-1000 rpm for 0.5-1 hour. Next, add potassium silicate and ethylene glycol sequentially, and mix at 500-1000 rpm for 0.5-1 hour to obtain the intermediate coating precursor, which contains C0-C4 alkyl dialkyldialkoxysilane, C8-C18 alkyl alkyltrialkoxysilane, and C0-C4 alkoxy tetraalkoxysilane separately. 0.5-1 hour before applying the intermediate coating, add the C0-C4 alkyl dialkyldialkoxysilane to the intermediate coating precursor and mix at 500-1000 rpm for 5-10 minutes. Immediately afterwards, add the C8-C18 alkyl alkyltrialkoxysilane and mix at 500-1000 rpm. Mix at rpm for 5-10 minutes, then add C0-C4 alkoxy tetraalkoxysilane and mix at 500-1000 rpm for 5-10 minutes to obtain the intermediate coating for later use.

[0039] The toughening crosslinking agents C0-C4 alkyl dialkyl diekoxysilane, C8-C18 alkyl alkyl trialkoxysilane, and C0-C4 alkoxy tetraalkoxysilane are stored separately. The toughening crosslinking agents and intermediate coating precursors are then mixed together 0.5-1 hours before the application of the intermediate coating to maximize the toughening effect of the toughening crosslinking agents.

[0040] The toughening crosslinking agent can also be premixed and then mixed together with the intermediate coating precursor. For example, in a premixing device, an appropriate diluent is added, and C0-C4 alkyl dialkyldialkoxysilane, C8-C18 alkyl alkyltrialkoxysilane and C0-C4 alkoxy tetraalkoxysilane are added in sequence. The mixture is stirred at 100-300 rpm for 5-10 minutes to obtain the premixed toughening crosslinking agent.

[0041] In addition, toughening crosslinking agents can also be directly added to the intermediate coating precursor. For example, after obtaining the intermediate coating precursor, C0-C4 alkyl dialkyl diekoxysilane, C8-C18 alkyl alkyl trialkoxysilane and C0-C4 alkoxy tetraalkoxysilane are added in sequence and mixed at a stirring speed of 100-300 rpm for 5-10 minutes to obtain the intermediate coating.

[0042] The primer coating is packaged separately and can be used as an intermediate coat for the heavy-duty anti-corrosion coating of this invention, or as a heat-resistant shock-resistant coating on its own.

[0043] Preparation of topcoat: First, weigh each component in the formula using a weighing device. Then, add the diluent and potassium silicate to the coating mixing equipment and mix at a stirring speed of 500-1000 rpm for 0.5-1 hour. Next, add fumed silica and mix at a stirring speed of 500-1000 rpm for 0.5-1 hour. Finally, add titanium dioxide, silicon carbide and stabilizer to the coating mixing equipment in sequence and mix at a stirring speed of 500-1000 rpm for 0.5-1 hour to obtain the topcoat, which is ready for use.

[0044] The primer coating is packaged separately and can be used as the top coat of the heavy-duty anti-corrosion coating of this invention, or as a high-temperature resistant coating on its own.

[0045] The second step is to apply the primer coating to the surface of the non-planar substrate to form a heavy-duty anti-corrosion primer coating, and then let it dry for 0.5-1 hour.

[0046] After the primer coat dries and cures in 1-2 hours, it can achieve surface dryness. It can be applied as a mid-coat coat without being completely dry, which can speed up the construction process and better utilize the cross-linking and toughening effect of the toughening cross-linking agent in the mid-coat coat.

[0047] The third step is to immediately apply the intermediate coating on the surface-dried heavy-duty anti-corrosion base coating after it has dried to form an anti-penetration and toughening intermediate coating, which is then dried for 1-2 hours.

[0048] After the intermediate coating dries and cures in 1-2 hours, it can achieve surface dryness. It can be applied as topcoat without being completely dry, which can speed up the construction and better exert the cross-linking and toughening effect of the toughening cross-linking agent in the intermediate coating.

[0049] The fourth step is to immediately apply the topcoat coating to the surface of the anti-permeability and toughening intermediate coating after it has dried to form a high-temperature resistant and fireproof topcoat. Finally, after 1-2 hours of drying and curing, a heavy-duty anti-corrosion coating is formed.

[0050] The process involves primer, surface drying, intermediate coating, surface drying, top coating, and drying and curing to form a heavy-duty anti-corrosion coating. It has lower VOC emissions than traditional solvent-based heavy-duty anti-corrosion coatings, and a shorter construction cycle and higher heat resistance than water-based polymer heavy-duty anti-corrosion coatings.

[0051] The technical effects of this application include:

[0052] The coating of this invention exhibits excellent flame retardancy; in a 1100℃ combustion test, the sample showed no expansion, cracking, perforation, or burning within 60 minutes. It also demonstrates good temperature resistance, with long-term resistance at 400℃ to 500℃ and instantaneous thermal shock at 550℃. Furthermore, it exhibits good toughness, high impact resistance, and excellent corrosion resistance; after 1500 hours, the sample surface showed no rust. It is also environmentally friendly, with low VOC emissions and a short construction period. Attached Figure Description

[0053] Figure 1 This application's coating schematic diagram Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] pass Figure 1 The present invention will be further described below.

[0056] Figure 1 It includes a base layer 1, a heavy-duty anti-corrosion base coating 2, an anti-permeability and toughening intermediate coating 3, a high-temperature resistant and fireproof top coating 4. Example 1

[0057] Inorganic heavy-duty anti-corrosion coating includes a heavy-duty anti-corrosion base layer, an anti-penetration toughening intermediate layer, and a high-temperature fireproof top layer. The heavy-duty anti-corrosion base layer is attached to the outer surface of the base layer, and the anti-penetration toughening intermediate layer is located between the heavy-duty anti-corrosion base layer and the high-temperature fireproof top layer.

[0058] The heavy-duty anti-corrosion primer is formed by applying a primer coating to the surface of the substrate. The primer coating consists of a silicone-based binder A, zinc powder, aluminum powder, an anti-permeability agent, and silicate stabilizer GSYWDJ-5, along with a diluent, in a mass ratio of 3:1.5:2:0.8:0.7:35. The silicone-based binder A consists of potassium silicate, potassium methylsilicate, and aluminum oxide in a mass ratio of 20:10:8.

[0059] The anti-permeability and toughening intermediate coating is formed by applying an intermediate coating onto a heavy-duty anti-corrosion base coating. The intermediate coating consists of a silicone-based binder B, an anti-permeability agent, a silicate stabilizer GSYWDJ-5, and a diluent in a mass ratio of 3:1.5:0.8:30. The silicone-based binder B consists of potassium silicate, ethylene glycol, and a toughening crosslinking agent in a mass ratio of 20:8:20. The toughening crosslinking agent consists of dimethyldimethoxysilane, dodecyltriethoxysilane, and tetra-n-butoxysilane in a molar ratio of 4:2.5:1.5.

[0060] The high-temperature fireproof topcoat is formed by applying a topcoat coating onto an impermeable and toughening intermediate coating. The topcoat coating consists of a silicon-based binder C, titanium dioxide, silicon carbide, and silicate stabilizer GSYWDJ-5 in a mass ratio of 1.5:2.5:2.5:1.5:25, as well as a diluent. Among them, the silicon-based binder C consists of potassium silicate and fumed silica in a mass ratio of 20:8.

[0061] Among them, diluent, B, and C are all mixed solutions of deionized water and anhydrous ethanol in a volume ratio of 5:3.

[0062] Among them, the modulus of potassium silicate is 2.8; Example 2

[0063] Inorganic heavy-duty anti-corrosion coating includes a heavy-duty anti-corrosion base layer, an anti-penetration toughening intermediate layer, and a high-temperature fireproof top layer. The heavy-duty anti-corrosion base layer is attached to the outer surface of the base layer, and the anti-penetration toughening intermediate layer is located between the heavy-duty anti-corrosion base layer and the high-temperature fireproof top layer.

[0064] The heavy-duty anti-corrosion primer is formed by applying a primer coating to the surface of the substrate. The primer coating consists of a silicone-based binder A, zinc powder, aluminum powder, anti-penetration agent, silicate stabilizer GSYWDJ-5, and diluent in a mass ratio of 3:1.5:2:0.8:0.7:35. The silicone-based binder A consists of sodium silicate, potassium methylsilicate, and aluminum oxide in a mass ratio of 20:10:8.

[0065] The anti-permeability and toughening intermediate coating is formed by applying an intermediate coating onto a heavy-duty anti-corrosion base coating. The intermediate coating consists of a silicone-based binder B, an anti-permeability agent, a silicate stabilizer GSYWDJ-5, and a diluent in a mass ratio of 3:1.5:0.8:30. The silicone-based binder B consists of sodium silicate, ethylene glycol, and a toughening crosslinking agent in a mass ratio of 20:8:20. The toughening crosslinking agent consists of diethoxysilane, hexadecyltriethoxysilane, and tetraethoxysilane in a molar ratio of 4:2.5:1.5.

[0066] The high-temperature fireproof topcoat is formed by applying a topcoat coating onto an impermeable and toughening intermediate coating. The topcoat coating consists of a silicon-based binder C, titanium dioxide, silicon carbide, and silicate stabilizer GSYWDJ-5 in a mass ratio of 1.5:2.5:2.5:1.5:25, as well as a diluent. Among them, the silicon-based binder C consists of sodium silicate and fumed silica in a mass ratio of 20:8.

[0067] Among them, diluent, B, and C are all mixed solutions of deionized water and anhydrous ethanol in a volume ratio of 5:3.

[0068] Sodium silicate has a modulus of 3.3. Example 3

[0069] Using the component formulation of Example 1, the coating was prepared as follows:

[0070] The first step is to prepare the primer, intermediate coat, and top coat separately.

[0071] Preparation of primer coating: First, weigh each component in the formula using a weighing device. Then, add the diluent, potassium silicate, and potassium methylsilicate to the coating mixing equipment and mix at 500 rpm for 1 hour. Next, add fumed silica and mix at 500 rpm for 1 hour. Finally, add zinc powder, aluminum powder, anti-penetration agent, and silicate stabilizer GSYWDJ-5 to the coating mixing equipment in sequence and mix at 500 rpm for 1 hour to obtain the primer coating for later use.

[0072] Preparation of intermediate coating: First, weigh each component in the formula using a weighing device. Then, add the anti-penetration agent, silicate stabilizer GSYWDJ-5, and diluent to the coating mixing equipment and mix at 500 rpm for 1 hour. Next, add potassium silicate and ethylene glycol sequentially and mix at 500 rpm for 1 hour to obtain the intermediate coating precursor. Separately store dimethyldimethoxysilane, dodecyltriethoxysilane, and tetra-n-butoxysilane. One hour before applying the intermediate coating, add dimethyldimethoxysilane to the intermediate coating precursor and mix at 100 rpm for 10 minutes. Immediately afterward, add dodecyltriethoxysilane and mix at 100 rpm for 10 minutes. Finally, add tetra-n-butoxysilane and mix at 100 rpm for 10 minutes to obtain the intermediate coating for later use.

[0073] Preparation of topcoat: First, weigh each component in the formula using a weighing device. Then, add the diluent and potassium silicate to the coating mixing device and mix at 500 rpm for 1 hour. Next, add fumed silica and mix at 500 rpm for 1 hour. Finally, add titanium dioxide, silicon carbide and silicate stabilizer GSYWDJ-5 to the coating mixing device in sequence and mix at 500 rpm for 1 hour to obtain the topcoat.

[0074] The second step is to apply the primer coating to the surface of the flat substrate to form a heavy-duty anti-corrosion primer coating, and let it dry for 2 hours.

[0075] The third step is to immediately apply the intermediate coating on the surface-dried heavy-duty anti-corrosion base coating after it has dried to form an anti-penetration and toughening intermediate coating, which is then dried for 1 hour.

[0076] The fourth step is to immediately apply the topcoat coating to the surface of the anti-permeability and toughening intermediate coating after it has dried to form a high-temperature resistant and fireproof topcoat. Finally, after 2 hours of drying and curing, a heavy-duty anti-corrosion coating is formed. Example 4

[0077] Using the component formulation of Example 2, the coating was prepared as follows:

[0078] The first step is to prepare the primer, intermediate coat, and top coat separately.

[0079] Preparation of primer coating: First, weigh each component in the formula using a weighing device. Then, add the diluent, sodium silicate, and potassium methylsilicate to the coating mixing equipment and mix at 1000 rpm for 0.5 hours. Next, add fumed silica and mix at 1000 rpm for 0.5 hours. Finally, add zinc powder, aluminum powder, anti-penetration agent, and silicate stabilizer GSYWDJ-5 to the coating mixing equipment in sequence and mix at 1000 rpm for 0.5 hours to obtain the primer coating for later use.

[0080] Preparation of intermediate coating: First, weigh each component in the formula using a weighing device. Then, add the anti-penetration agent, silicate stabilizer GSYWDJ-5, and diluent to a coating mixing device and mix at 1000 rpm for 0.5 hours. Next, add potassium silicate and ethylene glycol sequentially and mix at 1000 rpm for 0.5 hours to obtain the intermediate coating precursor. Store diethoxysilane, hexadecyltriethoxysilane, and tetraethoxysilane separately. 0.5 hours before applying the intermediate coating, add diethoxysilane to the intermediate coating precursor and mix at 300 rpm for 5 minutes. Immediately after, add hexadecyltriethoxysilane and mix at 300 rpm for 5 minutes. Finally, add tetraethoxysilane and mix at 300 rpm for 5 minutes to obtain the intermediate coating.

[0081] Preparation of topcoat: First, weigh each component in the formula using a weighing device. Then, add the diluent and potassium silicate to the coating mixing device and mix at 1000 rpm for 0.5 hours. Next, add fumed silica and mix at 1000 rpm for 0.5 hours. Finally, add titanium dioxide, silicon carbide and silicate stabilizer GSYWDJ-5 to the coating mixing device in sequence and mix at 1000 rpm for 1 hour to obtain the topcoat, which is then ready for use.

[0082] The second step is to apply the primer coating to the surface of the non-planar substrate to form a heavy-duty anti-corrosion primer coating, and let it dry for 2 hours.

[0083] The third step is to immediately apply the intermediate coating on the surface-dried heavy-duty anti-corrosion base coating after it has dried to form an anti-penetration and toughening intermediate coating, which is then dried for 1 hour.

[0084] Fourth, immediately after the anti-permeability and toughening intermediate coating has dried to the surface, apply the topcoat to the dried surface of the anti-permeability and toughening intermediate coating to form a high-temperature resistant and fireproof topcoat. Finally, after 2 hours of drying and curing, a heavy-duty anti-corrosion coating is formed.

[0085] Comparative Example 1: The difference between Comparative Example 2 and Example 1 is that no intermediate coating is added; the preparation method of Example 3 is also used to prepare the primer coating and topcoat coating, and then they are applied.

[0086] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that the toughening crosslinking agent in the anti-permeation and toughening intermediate coating is replaced with dimethyldimethoxysilane and tetra-n-butoxysilane in a molar ratio of 5:3, while the rest remains unchanged. The intermediate coating is prepared using the same method as in Example 3: First, each component in the formula is weighed using a weighing device. Then, the anti-permeation agent, silicate stabilizer GSYWDJ-5, and diluent are added to the coating mixing device and mixed at 500 rpm for 1 hour. Next, potassium silicate and ethylene glycol are added sequentially and mixed at 500 rpm for 1 hour to obtain the intermediate coating precursor. Dimethyldimethoxysilane and tetra-n-butoxysilane are stored separately. One hour before applying the intermediate coating, dimethyldimethoxysilane is added to the intermediate coating precursor and mixed at 100 rpm for 10 minutes. Then, tetra-n-butoxysilane is added and mixed at 100 rpm for 10 minutes to obtain the intermediate coating.

[0087] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that the toughening crosslinking agent in the anti-permeability and toughening intermediate coating is replaced with dodecyltriethoxysilane and tetra-n-butoxysilane in a molar ratio of 5:3, while the rest remains unchanged. The intermediate coating is prepared using the same method as in Example 3: First, each component in the formula is weighed using a weighing device. Then, the anti-permeability agent, silicate stabilizer GSYWDJ-5, and diluent are added to the coating mixing device and mixed at 500 rpm for 1 hour. Next, potassium silicate and ethylene glycol are added sequentially and mixed at 500 rpm for 1 hour to obtain the intermediate coating precursor. Dodecyltriethoxysilane and tetra-n-butoxysilane are stored separately. One hour before applying the intermediate coating, dodecyltriethoxysilane is added to the intermediate coating precursor and mixed at 100 rpm for 10 minutes. Then, tetra-n-butoxysilane is added and mixed at 100 rpm for 10 minutes to obtain the intermediate coating.

[0088] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that the toughening crosslinking agent in the anti-permeation and toughening intermediate coating is replaced with dimethyldimethoxysilane and dodecyltriethoxysilane in a molar ratio of 5:3, while the rest remains unchanged. The intermediate coating is prepared using the same method as in Example 3: First, each component in the formula is weighed using a weighing device. Then, the anti-permeation agent, silicate stabilizer GSYWDJ-5, and diluent are added to the coating mixing device and mixed at 500 rpm for 1 hour. Next, potassium silicate and ethylene glycol are added sequentially and mixed at 500 rpm for 1 hour to obtain the intermediate coating precursor. Dimethyldimethoxysilane and dodecyltriethoxysilane are stored separately. One hour before applying the intermediate coating, dimethyldimethoxysilane is added to the intermediate coating precursor and mixed at 100 rpm for 10 minutes. Immediately afterwards, dodecyltriethoxysilane is added and mixed at 100 rpm for 10 minutes to obtain the intermediate coating.

[0089] Example 5: The difference between Example 5 and Example 1 is that the toughening crosslinking agent in the anti-permeation and toughening intermediate coating is replaced with a toughening crosslinking agent composed of dimethylsilane, dodecyltriethoxysilane, and tetraethoxysilane in a molar ratio of 4:2.5:1.5; the rest remains unchanged. The intermediate coating is prepared using the same method as in Example 3: First, each component in the formula is weighed using a weighing device. Then, the anti-permeation agent, silicate stabilizer GSYWDJ-5, and diluent are added to a coating mixing device and mixed at 500 rpm for 1 hour. Next, potassium silicate and ethylene glycol are added sequentially and mixed at 500 rpm for 1 hour to obtain the intermediate coating precursor. Dimethyldimethoxysilane, dodecyltriethoxysilane, and tetrabutoxysilane are stored separately. One hour before applying the intermediate coating, dimethyldimethoxysilane is added to the intermediate coating precursor and mixed at 100 rpm for 10 minutes. Immediately afterwards, dodecyltriethoxysilane is added and mixed at 100 rpm. Mix at 100 rpm for 10 minutes, then add tetraethoxysilane and mix at 100 rpm for 10 minutes to obtain the intermediate coating.

[0090] The coatings prepared in the examples and comparative examples were uniformly applied to flat steel. After the coatings dried (2 hours), the test was placed at 450°C for 240 hours, and then returned to room temperature. Adhesion was tested according to standard ISO 2409-2020, impact strength was tested according to standard GB / T 1732-2020, and salt spray test was conducted according to standard GB / T 10125-2021. The test results are shown in Table 1 below.

[0091] Table 1. Test results for examples and comparative examples.

[0092]

[0093] Examples 3 and Comparative Examples 1-4 were planar substrate samples, while Example 4 was a non-planar substrate sample. Test results show that Examples 3-5 performed relatively well, with Examples 3-4 being the best, exhibiting good adhesion ratings and impact strength. Comparative Example 1 lacked an intermediate layer, resulting in significantly poor adhesion and impact strength. Comparative Examples 2-4 were slightly better than Comparative Example 1, but still slightly better than Examples 3-5. Furthermore, Example 3 showed better impact strength than Example 5, possibly due to differences in the toughening crosslinking agent composition.

[0094] It's possible that the enhanced high-temperature toughness and good adhesion are due to the combined effect of the three components in the toughening crosslinking agent. However, the lack of any one of the following—a C0-C4 alkyl dialkyldialkoxysilane, a C8-C18 alkyl alkyltrialkoxysilane, or a C0-C4 alkoxy tetraalkoxysilane—results in decreased adhesion and inability to achieve high-temperature toughening. Furthermore, C4 alkoxy tetra-n-butoxysilane is more effective than other alkoxysilanes, such as tetraethoxysilane.

[0095] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. 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.

Claims

1. An inorganic heavy-duty anti-corrosion coating with good toughness, characterized in that: From the base layer outwards, the coating consists of a heavy-duty anti-corrosion base layer, an anti-permeability and toughening intermediate layer, and a high-temperature and fire-resistant top layer. The anti-permeability and toughening intermediate layer is formed by applying an intermediate coating onto the heavy-duty anti-corrosion base layer. The intermediate coating includes a silicone-based binder B, an anti-permeability agent, a stabilizer, and a diluent. The silicone-based binder B is composed of potassium silicate, ethylene glycol, and a toughening crosslinking agent in a mass ratio of 10-30:5-10:15-25. The intermediate coating consists of silicone-based binder B, anti-permeability agent, stabilizer, and diluent in a mass ratio of 2-4:1-2:0.5-1:20-40; the toughening and crosslinking agent consists of CO-C4 alkyl dialkyl diekoxysilane, C8-C18 alkyl alkyl trialkoxysilane, and CO-C4 alkoxy tetraalkoxysilane in a molar ratio of 3-5:2-3:1-2, where CO alkyl refers to H replacing alkyl and being directly connected to Si; C0-C4 alkyl dialkyldialkoxysilanes are selected from one or more of dimethoxysilane, diethoxysilane, methyldimethoxysilane, ethyldiethoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, dimethyldiethoxysilane, and diethyldiethoxysilane. The C8-C18 alkyl alkyltrialkoxysilane is selected from one or more of octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, tetradecyltrimethoxysilane, tetradecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, and octadecyltriethoxysilane.

2. The inorganic heavy-duty anti-corrosion coating with good toughness according to claim 1, characterized in that: The heavy-duty anti-corrosion primer is formed by applying a primer coating to the surface of the substrate. The primer coating includes a silicone-based binder, zinc powder, aluminum powder, anti-penetration agent, stabilizer, and diluent. The silicone-based binder A is composed of potassium silicate or sodium silicate, potassium methylsilicate, and aluminum oxide in a mass ratio of 10-30:5-15:5-10.

3. The inorganic heavy-duty anti-corrosion coating with good toughness according to any one of claims 1-2, characterized in that: The high-temperature fireproof topcoat is formed by applying a topcoat coating onto an anti-permeability and toughening intermediate coating. The topcoat coating consists of a silicon-based binder C, titanium dioxide, silicon carbide, stabilizer, and diluent in a mass ratio of 1-2:2-3:2-3:1-2:20-30. The silicon-based binder C consists of potassium silicate and fumed silica in a mass ratio of 10-30:5-10.

4. A method for preparing a tough inorganic heavy-duty anti-corrosion coating as described in any one of claims 1-3, characterized in that: The first step is to prepare the primer, intermediate coat, and top coat separately. The intermediate coating includes silicone-based binder B, anti-penetration agent, stabilizer, and diluent. Silicone-based binder B is composed of potassium silicate, ethylene glycol, and toughening crosslinking agent in a mass ratio of 10-30:5-10:15-25. The toughening crosslinking agent is composed of CO-C4 alkyl dialkyl diekoxysilane, C8-C18 alkyl alkyl trialkoxysilane, and CO-C4 alkoxy tetraalkoxysilane in a molar ratio of 3-5:2-3:1-2. CO alkyl refers to H replacing alkyl and being directly connected to Si. The second step is to apply the primer coating to the surface of the non-planar substrate to form a heavy-duty anti-corrosion primer coating and let it dry. The third step is to immediately apply the intermediate coating onto the surface-dried heavy-duty anti-corrosion primer after it has dried to form an anti-penetration and toughening intermediate coating, and then let it dry. The fourth step is to immediately apply the topcoat coating to the surface of the anti-permeability and toughening intermediate coating after it has dried to form a high-temperature resistant and fireproof topcoat. Finally, it is dried and cured to form a heavy-duty anti-corrosion coating.

5. The method for preparing a tough inorganic heavy-duty anti-corrosion coating according to claim 4, characterized in that: The thickness of the heavy-duty anti-corrosion primer is 0.5-2mm; the thickness of the anti-permeability toughening intermediate coating is 0.2-1mm; and the thickness of the high-temperature resistant fireproof topcoat is 0.2-1mm.

6. The application of a tough inorganic heavy-duty anti-corrosion coating as described in any one of claims 1-3, characterized in that, Suitable for planar and non-planar substrates in the chemical industry.

7. The application of the inorganic heavy-duty anti-corrosion coating with good toughness according to claim 6, characterized in that: The non-planar substrate is selected from at least one of chemical pipelines and valves.

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