Low-voc environment-friendly quick-drying resin anticorrosive paint and preparation method thereof

Abstract

This invention belongs to the field of anti-corrosion coating technology and discloses a low-VOC environmentally friendly quick-drying resin anti-corrosion paint and its preparation method. The anti-corrosion paint is formed by mixing a resin component and a curing agent component in a specific ratio. The resin component includes epoxy resin, pigments, fillers, and epoxy-modified amphiphilic surface-active components. The curing agent component includes a modified cycloaliphatic amine curing agent and a second low-rate curing component. By constructing a dual-rate curing system, a gradient curing structure from the surface to the interior of the coating is achieved, avoiding cracking and delamination problems caused by the lag in the surface drying of thick coatings. Simultaneously, the reactive surface-active components are used to regulate interfacial flow behavior, improving the anti-sagging performance during application. The coating of this invention has a surface drying time of ≤10 minutes at 25℃, and features low VOC emissions, low viscosity for easy application, simultaneous curing of thick coatings, and excellent anti-corrosion performance, making it suitable for surface protection of metal structures and engineering equipment.

Description

Technical Field

[0001] This invention belongs to the field of anti-corrosion coating technology, specifically relating to a low-VOC environmentally friendly quick-drying resin anti-corrosion paint and its preparation method. Background Technology

[0002] Epoxy resin anti-corrosion coatings are widely used for surface protection of metal substrates such as bridges, steel structures, storage tanks, and engineering equipment due to their excellent adhesion, corrosion resistance, and mechanical properties. However, with increasing demands for construction efficiency and increasingly stringent environmental regulations, traditional epoxy anti-corrosion paint systems have gradually revealed several technical shortcomings in practical applications. On the one hand, to achieve rapid surface drying, existing technologies typically use highly active curing agents or add accelerators to accelerate the crosslinking reaction rate. However, such single-rate curing systems are prone to rapid surface curing followed by delayed internal curing during thick-film application, leading to stress concentration within the coating film and defects such as cracking, blistering, or decreased adhesion, thus affecting the anti-corrosion lifespan. On the other hand, to ensure leveling during application, the coating system usually needs to maintain a low viscosity. However, low-viscosity systems are prone to sagging during vertical or thick-film application. Existing solutions often control this by increasing the system viscosity or adding a large amount of thixotropic agent. While this can suppress sagging to some extent, it often reduces coating leveling and workability. Furthermore, with increasingly stringent environmental requirements for low VOCs, reducing solvent usage has become a development trend. However, balancing curing efficiency, application performance, and the stability of thick coating quality while reducing volatile organic compound content remains a technical challenge. Therefore, developing an epoxy anticorrosive paint system that combines low VOC emissions, rapid surface drying, simultaneous thick coating curing, and excellent anti-sagging properties has become a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0003] To address the shortcomings mentioned in the background art, the present invention aims to provide a low-VOC, environmentally friendly, quick-drying resin anti-corrosion paint and its preparation method. This anti-corrosion paint is a two-component system, formed by mixing a resin component and a curing agent component in a specific mass ratio. The curing agent component employs a modified alicyclic amine curing agent and a second low-rate curing component to form a dual-rate curing system, resulting in a difference in curing rate from the surface to the interior during the coating curing process and promoting consistent curing throughout the thick coating. The resin component incorporates an epoxy-modified amphiphilic surfactant component, which creates a surface tension gradient in the early stages of curing and regulates interfacial flow, thereby suppressing sagging and improving the film appearance. The present invention achieves surface drying at 25°C for ≤10 min while meeting low VOC requirements and improves the stability and anti-corrosion durability of thick coatings.

[0004] The objective of this invention can be achieved through the following technical solutions: A low-VOC, environmentally friendly, quick-drying resin anti-corrosion paint is formed by mixing resin components and curing agent components at a mass ratio of 2.0 to 2.5:1. The resin components, by weight, comprise: 40-45 parts epoxy resin, 32-36 parts pigments and fillers, 0.4-0.8 parts dispersant, 0.1-0.4 parts defoamer, 0.8-2 parts viscosity control agent, 0.2-0.8 parts leveling agent, 0.5-2 parts epoxy-modified amphiphilic surfactant, 8-12 parts environmentally friendly solvent, and 5-10 parts diluent. The curing agent components, by mass parts, include: 70-80 parts of modified alicyclic amine curing agent R-3329, 20-30 parts of the second low-rate curing component, and 15-25 parts of butanol; The second low-rate curing component comprises a polyamide curing agent; The epoxy-modified amphiphilic surfactant component is an epoxy-modified polyether silicone surfactant or an epoxy-modified acetylenic diol surfactant.

[0005] More preferably, the second low-rate curing component comprises a polyamide curing agent and a microencapsulated latent imidazole curing agent, and the mass ratio of the microencapsulated latent imidazole curing agent to the polyamide curing agent is 1:1 to 2.

[0006] More preferably, the epoxy resin is a bisphenol A type epoxy resin with an epoxy equivalent of 180-190.

[0007] More preferably, the pigment filler comprises, by mass parts: 10-15 parts titanium dioxide, 0.1-0.3 parts carbon black, 6-10 parts precipitated barium sulfate, 6-10 parts talc, and 4-8 parts aluminum tripolyphosphate, and the total mass parts of the above pigment filler are 32-36 parts, with the remainder being unavoidable impurities.

[0008] More preferably, the microencapsulated latent imidazole curing agent uses polyurea resin as the wall material and 2-ethyl-4-methylimidazolium as the core material, with a core-to-wall mass ratio of 3 to 5:1, and is prepared by in-situ polymerization to obtain a microencapsulated curing agent with a particle size of 10 to 30 μm.

[0009] More preferably, the epoxy-modified acetylenic diol surfactant is prepared by graft polymerization of acetylenic diol surfactant and epoxy-containing acrylate monomer under the action of a free radical initiator.

[0010] More preferably, the dispersant is a polymeric dispersant, the defoamer is an organosilicon defoamer, the viscosity control agent is a polyamide wax thixotropic agent, the leveling agent is an organosilicon leveling agent; the environmentally friendly solvent is a mixture of butanol and C3-C6 ketone solvents; and the diluent is a mixture of C3-C8 ester solvents.

[0011] More preferably, the low-VOC environmentally friendly quick-drying resin anticorrosive paint has a surface drying time of ≤10 minutes at 25℃.

[0012] A method for preparing a low-VOC, environmentally friendly, quick-drying resin anticorrosive paint, characterized by comprising the following steps: S1. Prepare resin components by mixing and grinding epoxy resin, dispersant, leveling agent and pigment filler, then adding defoamer, viscosity control agent and environmentally friendly solvent and mixing, then adding epoxy-modified amphiphilic surfactant component, adjusting viscosity and filtering to obtain resin components; S2. Prepare the curing agent component by mixing the modified cycloaliphatic amine curing agent with the second low-rate curing component, adding an environmentally friendly solvent, stirring evenly, and then filtering to obtain the curing agent component; S3. Mix the resin component and the curing agent component in proportion and stir evenly to obtain the low-VOC environmentally friendly quick-drying resin anti-corrosion paint.

[0013] More preferably, in step S1, the mixing and stirring speed is 800-1200 rpm, the grinding is carried out to a fineness of ≤20 μm, the subsequent stirring speed is 400-600 rpm, the system viscosity is controlled to a KU value ≥80, and 200-mesh filter material is used for filtration; when the second low-rate curing component contains microencapsulated latent imidazole curing agent, the stirring speed in step S2 is 250-350 rpm; when it does not contain microencapsulated latent imidazole curing agent, the stirring speed is 400-600 rpm.

[0014] The beneficial effects of this invention are: This invention significantly improves the overall performance of epoxy anticorrosive coating systems through synergistic design in two dimensions: curing reaction kinetics and interfacial physical regulation. The invention employs a modified alicyclic amine curing agent and a low-reaction-rate curing component to construct a dual-rate gradient curing system. Utilizing the differences in reaction rate constants and diffusion behavior of different curing agents, a gradient curing rate distribution from the surface to the interior is formed during the curing process. In the initial curing stage, the highly reactive component preferentially forms an initial cross-linked network structure on the surface, rapidly establishing surface dry strength. In the later curing stage, the low-reactive component continuously diffuses into the interior of the coating and completes the cross-linking reaction, thereby achieving simultaneous curing of the interior and surface of the thick coating. This avoids defects such as cracking, blistering, and decreased interlayer adhesion caused by the "surface dryness with internal hysteresis" in traditional single-rate systems, improving the overall structural stability and durability of the coating film. In terms of interface physical control, this invention introduces an amphiphilic surface-active component with epoxy reactivity. In the early stage of curing, it spontaneously migrates to form a controllable surface tension gradient field. It utilizes the Marangoni effect to generate shear backflow opposite to the direction of gravity, effectively suppressing sagging during the low-viscosity application stage. At the same time, it can maintain good application leveling without relying on a significant increase in system viscosity. As the curing reaction proceeds, the surface-active component participates in cross-linking and is fixed in the network structure, avoiding later migration failure and ensuring long-term stability of the coating film. Attached Figure Description

[0015] The invention will now be further described with reference to the accompanying drawings.

[0016] Figure 1 Bar chart comparing the surface drying time and actual drying time of the anti-corrosion paints prepared in Examples 1-4 and Comparative Examples 1-2. Detailed Implementation

[0017] 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.

[0018] Example 1: The low-VOC environmentally friendly quick-drying resin anti-corrosion paint is formed by mixing resin components and a curing agent; The resin components, by weight, comprise: 40 parts epoxy resin, 32 parts pigment filler, 0.4 parts dispersant, 0.1 parts defoamer, 0.8 parts viscosity control agent, 0.2 parts leveling agent, 0.5 parts epoxy-modified amphiphilic surfactant, 8 parts environmentally friendly solvent, and 5 parts diluent. The curing agent components, by mass parts, comprise: 70 parts of modified alicyclic amine curing agent R-3329, 20 parts of the second low-rate curing component, and 15 parts of butanol; S1. Weigh 4 kg of bisphenol A type epoxy resin (epoxy equivalent 185) and add it to a dispersion vessel. Stir evenly at room temperature. Add 0.04 kg of Efka-4401 dispersant and 0.02 kg of BYK-377 silicone leveling agent and mix evenly. Then, add 1.2 kg of titanium dioxide, 0.02 kg of carbon black, 0.8 kg of precipitated barium sulfate, 0.6 kg of talc, and 0.58 kg of aluminum tripolyphosphate for high-speed dispersion and grind to a fineness ≤20 μm. Subsequently, add 0.01 kg of silicone defoamer, 0.08 kg of polyamide wax thixotropic agent, and 0.8 kg of environmentally friendly solvent (0.4 kg of butanol and 0.4 kg of methyl isobutyl ketone) and stir evenly. Then, add 0.05 kg of γ-glycidyl etheroxypropyltrimethoxysilane as the epoxy functional silicone surfactant component and mix evenly. Finally, add 0.5 kg of diluent (0.25 kg of butyl acetate and 0.25 kg of...). The viscosity of the system was adjusted to a KU value ≥ 80 at 25°C using propylene glycol methyl ether acetate (kg), and the resin component was obtained by filtration through a 200-mesh filter material.

[0019] S2. Weigh 3.5 kg of modified alicyclic amine curing agent R-3329 (amine value approximately 360 mgKOH / g, active hydrogen equivalent approximately 92) and mix them evenly with 1.0 kg of polyamide curing agent 650. Add 0.75 kg of butanol and stir evenly. Filter the mixture through a 200-mesh filter to obtain the curing agent components.

[0020] S3. Mix the resin component and the curing agent component at a weight ratio of 2.0:1, and stir evenly at room temperature to obtain a low-VOC environmentally friendly quick-drying resin anti-corrosion paint.

[0021] Example 2: The low-VOC environmentally friendly quick-drying resin anti-corrosion paint is formed by mixing resin components and a curing agent; The resin components, by mass parts, include: 45 parts epoxy resin, 36 parts pigment filler, 0.8 parts dispersant, 0.4 parts defoamer, 2 parts viscosity control agent, 0.8 parts leveling agent, 2 parts epoxy-modified amphiphilic surfactant, 12 parts environmentally friendly solvent, and 10 parts diluent. The curing agent components, by mass parts, comprise: 80 parts of modified alicyclic amine curing agent R-3329, 30 parts of the second low-rate curing component, and 25 parts of butanol; The preparation steps of the low-VOC environmentally friendly quick-drying resin anti-corrosion paint are as follows: S1. Weigh 4.5 kg of bisphenol A type epoxy resin E-51 (epoxy equivalent approximately 185) and add it to a dispersion vessel. Stir evenly at room temperature. Add 0.08 kg of Efka-4401 dispersant and 0.08 kg of BYK-377 silicone leveling agent and mix evenly. Then, add 1.5 kg of rutile titanium dioxide, 0.03 kg of carbon black, 1.0 kg of precipitated barium sulfate, 1.0 kg of talc, and 0.47 kg of aluminum tripolyphosphate in sequence, making the total amount of pigment and filler 3.6 kg. Disperse at high speed and grind to a fineness ≤20 μm using a sand mill. Subsequently, add 0.04 kg of AQ-501 silicone defoamer, 0.2 kg of Solthix 250 polyamide wax thixotropic agent, and 1.2 kg of environmentally friendly solvent (0.6 kg of butanol and 0.6 kg of methyl isobutyl ketone) and stir evenly. Then add 0.2 kg of... γ-glycidyl oxypropyltrimethoxysilane was mixed evenly, and finally 1.0 kg of diluent (0.5 kg butyl acetate and 0.5 kg propylene glycol methyl ether acetate) was added to adjust the viscosity of the system to a KU value ≥ 80 at 25°C. The mixture was then filtered through a 200-mesh filter to obtain the resin component.

[0022] S2. Weigh 4.0 kg of modified alicyclic amine curing agent R-3329 (amine value approximately 360 mgKOH / g, active hydrogen equivalent approximately 92) and mix them evenly with 1.5 kg of polyamide curing agent 650. Add 1.25 kg of butanol and stir evenly. Filter the mixture through a 200-mesh filter to obtain the curing agent components.

[0023] S3. Mix the resin component and the curing agent component at a mass ratio of 2.5:1, and stir evenly at room temperature to obtain a low-VOC environmentally friendly quick-drying resin anti-corrosion paint.

[0024] Example 3: The low-VOC environmentally friendly quick-drying resin anti-corrosion paint is formed by mixing resin components and a curing agent; The resin components, by weight, comprise: 42.5 parts epoxy resin, 34 parts pigment filler, 0.6 parts dispersant, 0.25 parts defoamer, 1.4 parts viscosity control agent, 0.5 parts leveling agent, 1.25 parts epoxy-modified amphiphilic surfactant, 10 parts environmentally friendly solvent, and 7.5 parts diluent. The curing agent components, by mass parts, comprise: 75 parts of modified alicyclic amine curing agent R-3329, 25 parts of a second low-rate curing component, and 20 parts of butanol; The preparation steps of the low-VOC environmentally friendly quick-drying resin anti-corrosion paint are as follows: S1. Weigh 4.25 kg of bisphenol A type epoxy resin E-51 (epoxy equivalent approximately 185) and add it to a dispersion vessel. Stir evenly at room temperature. Add 0.06 kg of Efka-4401 dispersant and 0.05 kg of BYK-377 silicone leveling agent and mix evenly. Then, add 1.35 kg of rutile titanium dioxide, 0.02 kg of carbon black, 0.9 kg of precipitated barium sulfate, 0.8 kg of talc, and 0.53 kg of aluminum tripolyphosphate in sequence, making the total amount of pigment and filler 3.4 kg. Disperse at high speed and grind to a fineness ≤20 μm using a sand mill. Subsequently, add 0.025 kg of AQ-501 silicone defoamer, 0.14 kg of Solthix 250 polyamide wax thixotropic agent, and 1.0 kg of environmentally friendly solvent (0.5 kg of butanol and 0.5 kg of methyl isobutyl ketone) and stir evenly. Finally, add 0.125 kg of... γ-glycidyl oxypropyltrimethoxysilane was mixed evenly, and finally 0.75 kg of diluent (0.375 kg of butyl acetate and 0.375 kg of propylene glycol methyl ether acetate) was added to adjust the viscosity of the system to a KU value ≥ 80 at 25°C. The mixture was then filtered through a 200-mesh filter to obtain the resin component. S2. Weigh 3.75 kg of modified alicyclic amine curing agent R-3329 (amine value approximately 360 mgKOH / g, active hydrogen equivalent approximately 92) and mix them evenly with 1.25 kg of polyamide curing agent 650. Add 1.0 kg of butanol and stir evenly. Filter the mixture through a 200-mesh filter to obtain the curing agent components. S3. Mix the resin component and the curing agent component at a mass ratio of 2.25:1, and stir evenly at room temperature to obtain a low-VOC environmentally friendly quick-drying resin anti-corrosion paint.

[0025] Example 4: The low-VOC environmentally friendly quick-drying resin anti-corrosion paint is formed by mixing resin components and a curing agent; The resin components, by weight, comprise: 42.5 parts epoxy resin, 34 parts pigment filler, 0.6 parts dispersant, 0.25 parts defoamer, 1.4 parts viscosity control agent, 0.5 parts leveling agent, 1.25 parts epoxy-modified amphiphilic surfactant, 10 parts environmentally friendly solvent, and 7.5 parts diluent. The curing agent components, by mass parts, comprise: 75 parts of modified alicyclic amine curing agent R-3329, 25 parts of a second low-rate curing component, and 20 parts of butanol; The second low-rate curing component is composed of a polyamide curing agent and a microencapsulated latent imidazole curing agent, and the mass ratio of the microencapsulated latent imidazole curing agent to the polyamide curing agent is 1.5:1.

[0026] The preparation steps of the low-VOC environmentally friendly quick-drying resin anti-corrosion paint are as follows: S1. The preparation method of the resin component is the same as the preparation method of step S1 in Example 3.

[0027] S2. Weigh 2-ethyl-4-methylimidazole as the core material, and weigh diisocyanate and polyamine as wall material reactants, and mix them at a core-to-wall mass ratio of 3-5:1. Dissolve the core material in an organic solvent to form an oil phase, and dissolve the dispersant in deionized water to form an aqueous phase. Under stirring conditions, add the oil phase to the aqueous phase for emulsification, and adjust the stirring intensity to make the droplet size 10-30 μm. Add diisocyanate and polyamine to the emulsion system to polymerize in situ at the oil-water interface to form a polyurea wall material that coats the core material. After the reaction is complete, cool, filter and collect the microcapsules, wash and vacuum dry at 40-60℃ to constant weight to obtain a microencapsulated latent imidazole curing agent. Then, weigh 3.75 kg of modified cycloaliphatic amine curing agent R-3329 and 0.75 kg of polyamide curing agent 650 and mix them evenly. Then, add 0.50 kg of microencapsulated latent imidazole curing agent and mix evenly. Then, add 1.0 kg of butanol and stir evenly. Filter through a 200-mesh filter to obtain the curing agent components.

[0028] S3. Mix the resin component and the curing agent component at a mass ratio of 2.25:1, and stir evenly at room temperature to obtain a low-VOC environmentally friendly quick-drying resin anti-corrosion paint.

[0029] Comparative Example 1: The low-VOC environmentally friendly quick-drying resin anti-corrosion paint is formed by mixing resin components and curing agents; The resin components, by weight, comprise: 42.5 parts epoxy resin, 34 parts pigment filler, 0.6 parts dispersant, 0.25 parts defoamer, 1.4 parts viscosity control agent, 0.5 parts leveling agent, 1.25 parts epoxy-modified amphiphilic surfactant, 10 parts environmentally friendly solvent, and 7.5 parts diluent. The curing agent components, by mass parts, include: 100 parts of modified alicyclic amine curing agent R-3329 and 20 parts of butanol; The preparation steps of the low-VOC environmentally friendly quick-drying resin anti-corrosion paint are as follows: S1. The preparation method of the resin component is the same as the preparation method of step S1 in Example 3.

[0030] S2. Weigh 5.0 kg of modified alicyclic amine curing agent R-3329 (amine value approximately 360 mgKOH / g, active hydrogen equivalent approximately 92) and add it to a stirred tank. Stir at 400–600 rpm for 15 min at 25–30℃. Add 1.0 kg of butanol and continue stirring for 20 min to make the system homogeneous. Control the system temperature ≤35℃. Filter through a 200-mesh filter to obtain the curing agent component.

[0031] S3. Mix the resin component and the curing agent component at a mass ratio of 2.25:1, stir at 300 rpm for 5 minutes at 25°C until uniform, and let stand for about 10 minutes to obtain the low VOC environmentally friendly quick-drying resin anti-corrosion paint described in Comparative Example 1.

[0032] Comparative Example 2: The low-VOC environmentally friendly quick-drying resin anti-corrosion paint is formed by mixing resin components and curing agents; The resin components, by weight, comprise: 42.5 parts epoxy resin, 34 parts pigment filler, 0.6 parts dispersant, 0.25 parts defoamer, 1.4 parts viscosity control agent, 0.5 parts leveling agent, 10 parts environmentally friendly solvent, and 8.75 parts diluent. The curing agent components, by mass parts, comprise: 75 parts of modified alicyclic amine curing agent R-3329, 25 parts of a second low-rate curing component, and 20 parts of butanol; The preparation steps of the low-VOC environmentally friendly quick-drying resin anti-corrosion paint are as follows: S1. Weigh 4.25 kg of bisphenol A type epoxy resin E-51 (epoxy equivalent approximately 185) and add it to a dispersion vessel. Stir at 300 rpm for 10 min at 25–35℃ to ensure uniform flow. Add 0.06 kg of Efka-4401 dispersant and 0.05 kg of BYK-377 silicone leveling agent and continue stirring for 10 min. While maintaining stirring, add 1.35 kg of rutile titanium dioxide, 0.02 kg of carbon black, 0.90 kg of precipitated barium sulfate, 0.80 kg of talc, and 0.53 kg of aluminum tripolyphosphate sequentially for dispersion. Increase the speed to 1000 rpm for high-speed dispersion for 30 min, and then grind the mixture in a sand mill until the fineness is ≤20 μm and the material temperature is ≤50℃. Return the ground slurry to the dispersion vessel and stir at 500 rpm. Add 0.025 kg of AQ-501 silicone defoamer and 0.14 kg of Solthix. 250 kg of polyamide wax thixotropic agent and 1.0 kg of environmentally friendly solvent (0.5 kg of butanol and 0.5 kg of methyl isobutyl ketone) were stirred evenly without adding γ-glycidyl etheroxypropyltrimethoxysilane, and 0.125 kg of diluent was added as an equal substitute. Finally, 0.875 kg of diluent (0.4375 kg of butyl acetate and 0.4375 kg of propylene glycol methyl ether acetate) was added to adjust the viscosity of the system to a KU value ≥ 80 at 25°C. The mixture was then filtered through a 200-mesh filter to obtain the resin component.

[0033] S2. Weigh 3.75 kg of modified alicyclic amine curing agent R-3329 (amine value approximately 360 mgKOH / g, active hydrogen equivalent approximately 92) and mix them evenly with 1.25 kg of polyamide curing agent 650. Add 1.0 kg of butanol and stir evenly. Filter the mixture through a 200-mesh filter to obtain the curing agent components.

[0034] S3. Mix the resin component and the curing agent component at a mass ratio of 2.25:1 (for example, take 2.25 kg of resin component and 1.0 kg of curing agent component), stir at 300 rpm for 5 min at 25℃ until uniform, and let stand for 10 min to obtain the low VOC environmentally friendly quick-drying resin anti-corrosion paint of Comparative Example 2.

[0035] Performance testing 1. Quick-drying performance and applicable application window test After uniformly mixing the samples from each embodiment and comparative example according to the specified mass ratio, the mixture was evenly applied to a degreased tinplate using a 500 μm wet film preparation tool at 25±1℃ and 50±5% relative humidity. Surface drying time and complete drying time were determined according to GB / T 1728: surface drying was defined as no adhesion to the touch, and complete drying was defined as no fingerprints left upon light pressure and no adhesion of the paint film. The usable life test was conducted by placing the mixed coating in a 25℃ environment and observing and recording the time from uniform mixing to the appearance of significant thickening, gelation, or inability to be applied normally; this was the usable life. The results are shown in Table 1 below.

[0036] Table 1 Quick-drying performance and usable period after construction

[0037] As shown in Table 1, the surface drying time of Examples 1-4 at 25℃ was ≤10 min, demonstrating good rapid drying performance. Examples 2 and 4 had surface drying times of only 6 min, indicating that the modified cycloaliphatic amine and gradient curing system effectively promoted rapid film formation on the surface. Compared with Comparative Example 1, although the surface drying time was similar, the actual drying time was significantly extended to 18 h, indicating that the single curing system had an inner layer curing lag problem. The actual drying times of Examples 3 and 4 were 11.0 h and 9.0 h respectively, significantly shortened, indicating that the dual-rate curing system is beneficial for simultaneous curing of the thick film inside and out. Comparative Example 2, lacking interfacial reactive components, showed extended surface and actual drying times, further proving that the system of the present invention did not significantly shorten the usable life while ensuring rapid drying.

[0038] 2. Test on consistency between simultaneous curing of thick coating and internal / external curing After mixing the samples from Examples 1-4 and Comparative Examples 1-2 uniformly according to the specified mass ratio, the mixture was coated onto a steel plate using a 500 μm wet film preparation device at 25±1℃ and 50±5% relative humidity, and allowed to cure for 7 days. The pencil hardness of the coating layer (0-50 μm), middle layer (150-200 μm), and bottom layer (0-50 μm near the substrate) was tested using the cross-cut adhesion test (1 mm spacing, 3M tape peel). Impact resistance was tested according to GB / T 1732 (normal impact, increasing impact height), expressed as the maximum impact height without cracking or peeling. Flexibility was tested according to GB / T 1731 cylindrical shaft bending method, expressed as the minimum shaft diameter without cracking. The results are shown in Table 2 below.

[0039] Table 2 Results of simultaneous curing and comprehensive mechanical property testing of thick coating

[0040] Table 2 shows that the anti-corrosion paints in Examples 1-4 exhibited minimal differences in pencil hardness between the surface, intermediate, and bottom layers under thick coating conditions. In particular, the intermediate and bottom layers of Examples 2-4 all reached grade H, indicating that the dual-rate gradient curing system can achieve relatively uniform cross-linking from the surface inwards, avoiding the phenomenon of delayed curing in the inner layer. The adhesion of the sample samples in the examples was all grade 0, and the impact resistance gradually improved with system optimization, reaching 65 cm in Example 4, indicating a more reasonable internal stress distribution while maintaining high hardness. In contrast, although Comparative Example 1 achieved a surface hardness of 2H, its adhesion dropped to grade 2, and its impact resistance and flexibility significantly decreased, indicating that a single curing system is prone to asynchronous curing and stress concentration problems in thick film conditions. The overall mechanical properties of Comparative Example 2 were also lower than those of the examples.

[0041] 3. Anti-sagging and leveling test After uniformly mixing the samples from Examples 1-4 and Comparative Examples 1-2 according to the specified mass ratio, the samples were tested at 25±1℃ and 50±5% relative humidity. The sag test employed a vertical steel plate stepped coating method: samples were coated with a wet film thickness of 200-600 μm onto degreased cold-rolled steel plates. The plates were then placed vertically and allowed to stand for 30 min. The lowest failure thickness at which obvious sag, flow marks, or accumulation appeared was recorded. The leveling / orange peel grade was visually rated: a 300 μm wet film was coated onto a horizontally placed plate, cured at 25℃ for 24 h, and then the orange peel grade was assessed under the same light source and observation distance, rated from 1 to 5, where grade 1 was no orange peel and grade 5 was severe orange peel. The results are shown in Table 3 below.

[0042] Table 3 Results of anti-sagging and leveling properties

[0043] As shown in Table 3, Examples 1-4 significantly improved the maximum non-sagging wet film thickness while maintaining good leveling properties. Examples 3 and 4, in particular, showed no significant sagging even at a wet film thickness of 600 μm, and the orange peel grade was 1, indicating a smooth coating surface and excellent leveling effect. This demonstrates that the system does not suppress flow by simply increasing viscosity, but rather achieves a balance between flow and stability under the control of interfacial tension. In contrast, Comparative Example 1 had a maximum non-sagging thickness of only 400 μm and an orange peel grade of 4, exhibiting obvious flow marks and surface roughness, indicating that a single system cannot simultaneously achieve both anti-sagging and leveling properties. Comparative Example 2 showed slight improvement, but its overall performance was still lower than the examples.

[0044] 4. Corrosion resistance test After mixing the anti-corrosion paint samples from Examples 1-4 and Comparative Examples 1-2 evenly according to the specified mass ratio, the mixture was applied to a sandblasted and degreased steel plate at 25±1℃ and 50±5% relative humidity to form a film. The dry film thickness was controlled at (200±20) μm, and the film was cured at 25℃ for 7 days. Salt spray testing was conducted according to GB / T 1771: an "X" shaped scratch was made on the coating surface down to the metal substrate, and the test plate was placed in a 5% NaCl salt spray chamber for continuous spraying for 480 h. After the test, the rust spread width and blistering level at the scratch were recorded. Water resistance / damp heat resistance testing was conducted according to GB / T 1733 and GB / T 1740: the test plates were immersed in deionized water at 25℃ for 168 h, or placed at (40±2)℃ and (95±5)% relative humidity for 240 h, and changes in blistering, gloss loss, rust, and adhesion were recorded. The results are shown in Table 4 below.

[0045] Table 4 Corrosion Resistance Results

[0046] As shown in Table 4, Examples 1-4 all exhibited excellent corrosion resistance. After 480 hours of salt spray testing, the rust spread width at the scratches was significantly smaller than that of the comparative examples, with Examples 3 and 4 showing only about 1.0 mm and 0.8 mm respectively. Furthermore, the blistering rating reached 9F, indicating that the coating still possessed good shielding and protective capabilities under salt spray conditions. Simultaneously, none of the examples showed significant blistering or rust after 168 hours of water resistance and 240 hours of damp heat testing, exhibiting only slight loss of gloss, indicating a stable coating structure and good water and moisture resistance. In contrast, Comparative Examples 1 and 2 showed significantly increased rust spread in the salt spray test and exhibited blistering or localized rust under water and damp heat conditions, indicating weaker protective capabilities.

[0047] 5. VOC content test After mixing the samples from Examples 1-4 and Comparative Examples 1-2 at the specified mass ratio, the mixture was allowed to stand at 25±1℃ for 10 min to eliminate air bubbles. The VOC content was determined according to ISO 11890-2. A certain amount of sample was weighed, and after appropriate pretreatment, the content of volatile organic compounds in the sample was determined by gas chromatography. The VOC content per unit volume of coating was calculated according to the standard method. Each sample was tested in triplicate, and the average value was taken. The test results are shown in Table 5 below.

[0048] Table 5. VOC content test results

[0049] As shown in Table 5, the VOC content of the systems in Examples 1-4 was significantly lower than that of the comparative examples. Specifically, the VOC contents of Examples 3 and 4 were 200 g / L and 195 g / L, respectively, demonstrating low levels of volatile organic compound emissions. In contrast, the VOC contents of Comparative Examples 1 and 2 reached 310 g / L and 280 g / L, respectively, significantly higher than those of the Example systems. These results indicate that the present invention, through synergistic optimization of the resin components, curing agent system, and solvent system, effectively reduces the amount of volatile organic solvents used in the system while ensuring good workability and curing performance, thereby significantly reducing VOC emissions.

[0050] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0051] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A low-VOC, environmentally friendly, quick-drying resin anti-corrosion paint, characterized in that, It is formed by mixing resin components and curing agent components at a mass ratio of 2.0 to 2.5:1; The resin components, by weight, comprise: 40-45 parts epoxy resin, 32-36 parts pigments and fillers, 0.4-0.8 parts dispersant, 0.1-0.4 parts defoamer, 0.8-2 parts viscosity control agent, 0.2-0.8 parts leveling agent, 0.5-2 parts epoxy-modified amphiphilic surfactant, 8-12 parts environmentally friendly solvent, and 5-10 parts diluent. The curing agent components, by mass parts, include: 70-80 parts of modified alicyclic amine curing agent R-3329, 20-30 parts of the second low-rate curing component, and 15-25 parts of butanol; The second low-rate curing component comprises a polyamide curing agent; The epoxy-modified amphiphilic surfactant component is an epoxy-modified polyether silicone surfactant or an epoxy-modified acetylenic diol surfactant.

2. The low-VOC environmentally friendly quick-drying resin anti-corrosion paint according to claim 1, characterized in that, The second low-rate curing component comprises a polyamide curing agent and a microencapsulated latent imidazole curing agent, wherein the mass ratio of the microencapsulated latent imidazole curing agent to the polyamide curing agent is 1:1 to 2.

3. The low-VOC environmentally friendly quick-drying resin anti-corrosion paint according to claim 1, characterized in that, The epoxy resin is a bisphenol A type epoxy resin with an epoxy equivalent of 180-190.

4. The low-VOC environmentally friendly quick-drying resin anti-corrosion paint according to claim 1, characterized in that, The pigments and fillers comprise, by mass fraction, 10-15 parts titanium dioxide, 0.1-0.3 parts carbon black, 6-10 parts precipitated barium sulfate, 6-10 parts talc, and 4-8 parts aluminum tripolyphosphate, with the total mass fraction of the above pigments and fillers being 32-36 parts, the remainder being unavoidable impurities.

5. The low-VOC environmentally friendly quick-drying resin anti-corrosion paint according to claim 2, characterized in that, The microencapsulated latent imidazole curing agent uses polyurea resin as the wall material and 2-ethyl-4-methylimidazolium as the core material, with a core-to-wall mass ratio of 3 to 5:1, and is prepared by in-situ polymerization to obtain a microencapsulated curing agent with a particle size of 10 to 30 μm.

6. The low-VOC environmentally friendly quick-drying resin anticorrosive paint according to claim 1, characterized in that, The epoxy-modified acetylenic diol surfactant is prepared by graft polymerization of acetylenic diol surfactants and epoxy-containing acrylate monomers under the action of a free radical initiator.

7. The low-VOC environmentally friendly quick-drying resin anti-corrosion paint according to claim 1, characterized in that, The dispersant is a polymeric dispersant, the defoamer is an organosilicon defoamer, the viscosity control agent is a polyamide wax thixotropic agent, and the leveling agent is an organosilicon leveling agent; the environmentally friendly solvent is a mixture of butanol and C3-C6 ketone solvents; and the diluent is a mixture of C3-C8 ester solvents.

8. The low-VOC environmentally friendly quick-drying resin anti-corrosion paint according to claim 1, characterized in that, The surface drying time of the anti-corrosion paint is ≤10 minutes at 25℃.

9. A method for preparing a low-VOC environmentally friendly quick-drying resin anticorrosive paint as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Prepare resin components by mixing and grinding epoxy resin, dispersant, leveling agent and pigment filler, then adding defoamer, viscosity control agent and environmentally friendly solvent and mixing, then adding epoxy-modified amphiphilic surfactant component, adjusting viscosity and filtering to obtain resin components; S2. Prepare the curing agent component by mixing the modified cycloaliphatic amine curing agent with the second low-rate curing component, adding an environmentally friendly solvent, stirring evenly, and then filtering to obtain the curing agent component; S3. Mix the resin component and the curing agent component in proportion and stir evenly to obtain the low-VOC environmentally friendly quick-drying resin anti-corrosion paint.

10. The preparation method according to claim 9, characterized in that, In step S1, the mixing speed is 800-1200 rpm, and the grinding is carried out until the fineness is ≤20μm. The subsequent stirring speed is 400-600 rpm, the system viscosity is controlled to KU value ≥80, and 200-mesh filter material is used for filtration. When the second low-rate curing component contains microencapsulated latent imidazole curing agent, the stirring speed in step S2 is 250-350 rpm; when it does not contain microencapsulated latent imidazole curing agent, the stirring speed is 400-600 rpm.

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