Anti-corrosion coating for coastal buildings and preparation method of anti-corrosion coating

Abstract

The invention discloses an anticorrosive paint for coastal buildings and a preparation method thereof, the paint comprises the following components in parts by weight: 40-60 parts of epoxy resin, 20-30 parts of polyurethane prepolymer, 10-20 parts of zinc powder, 5-15 parts of silicon dioxide filler, 1-5 parts of silane coupling agent, 0.5-2 parts of dispersing agent and 30-50 parts of solvent. The preparation method comprises the following steps: mixing, heating and stirring the epoxy resin and the polyurethane prepolymer, adding the zinc powder and the silicon dioxide filler, continuously stirring, adding the silane coupling agent and the dispersing agent, uniformly mixing, and finally adding the solvent to adjust the viscosity. The coating is suitable for the surface of a coastal building, and has corrosion resistance and salt spray resistance.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating technology, specifically to an anti-corrosion coating for coastal buildings and its preparation method. Background Technology

[0002] Coastal buildings are exposed to the marine environment, facing high humidity, salt spray, seawater erosion, and ultraviolet radiation. These conditions make building surface materials susceptible to corrosion, affecting structural integrity and service life. Existing anti-corrosion coatings are usually based on single resin systems, such as epoxy resin or polyurethane coatings, which exhibit some protective effect in mild environments, but have limitations when applied to coastal buildings. For example, some coatings show decreased adhesion under salt spray conditions, resulting in blistering or peeling of the coating and a short protective time. Other coatings, although containing anti-corrosion fillers such as zinc powder, suffer from uneven dispersion of fillers in the base material, resulting in weak local protection and unstable overall corrosion resistance.

[0003] Furthermore, in existing preparation methods, improper control of the mixing process can lead to phase separation of components or excessively high viscosity, affecting the ease of application. In coastal areas, building surfaces often have moisture or salt residue, and existing coating systems lack sufficient wettability and adhesion to these substrates, making them prone to failure in dynamic environments. Some coatings attempt to improve the interface by adding coupling agents, but the effect is limited when the component ratios are not well-balanced.

[0004] To address these issues, a corrosion-resistant coating with balanced components and a controllable preparation process is needed to adapt to the complex environment of coastal buildings and improve the coating's durability and protective capabilities. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the prior art, the inventors have proposed the present invention.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide an anti-corrosion coating for coastal buildings and its preparation method.

[0008] This invention provides an anti-corrosion coating for coastal buildings, comprising, by weight, 40-60 parts epoxy resin, 20-30 parts polyurethane prepolymer, 10-20 parts zinc powder, 5-15 parts silica filler, 1-5 parts silane coupling agent, 0.5-2 parts dispersant, and 30-50 parts solvent.

[0009] Preferably, the epoxy resin is a bisphenol A type epoxy resin with a molecular weight between 400 and 600.

[0010] Preferably, the polyurethane prepolymer is an isocyanate-terminated polyether-type polyurethane prepolymer.

[0011] Preferably, the zinc powder is flake-shaped zinc powder with a particle size of 10-50 micrometers.

[0012] Preferably, the silica filler is fumed silica with a particle size of 10-100 nanometers.

[0013] Preferably, the silane coupling agent is γ-aminopropyltriethoxysilane.

[0014] Preferably, the dispersant is a polycarboxylate-type dispersant.

[0015] Preferably, the solvent is a mixture of xylene and butanol in a ratio of 7:3.

[0016] The present invention also provides a method for preparing the anti-corrosion coating, comprising the following steps: (1) Add epoxy resin and polyurethane prepolymer to a reaction vessel and stir at 50-70℃ for 30-60 minutes until uniformly mixed; (2) Add zinc powder and silica filler to the mixture obtained in step (1) and stir at room temperature for 20-40 minutes; (3) Add silane coupling agent and dispersant to the mixture obtained in step (2) and continue stirring for 10-20 minutes; (4) Slowly add solvent to the mixture obtained in step (3), stir evenly, and adjust the viscosity to 50-80 seconds (Ford-4 cup) to obtain the anti-corrosion coating.

[0017] Preferably, the stirring speed in step (1) is 300-500 rpm.

[0018] Preferably, the stirring speed in step (2) is 400-600 rpm.

[0019] Preferably, the stirring speed in step (3) is 200-400 rpm.

[0020] Preferably, the solvent addition rate in step (4) is 5-10 parts / minute. The beneficial effects of this invention are as follows: Epoxy resin provides adhesion and chemical stability to the base material, and when combined with polyurethane prepolymer, it enhances the flexibility of the coating, adapting to temperature and humidity changes in coastal buildings; Zinc powder acts as a sacrificial anode, blocking the penetration of corrosive media; Silica filler enhances the density of the coating, reduces micropore formation, and improves salt spray resistance; Silane coupling agent improves the interfacial bonding between filler and resin; Dispersant promotes uniform distribution of components and avoids sedimentation; Solvent adjusts viscosity, facilitating construction.

[0021] This preparation method ensures component compatibility through stepwise mixing, requires no complex operating conditions, and improves production consistency. In a simulated coastal environment, the coating exhibits salt spray resistance of 1000-1400 hours, adhesion of 0-1 grade, and no significant change after 7-14 days of water immersion. These properties help extend the maintenance cycle of coastal buildings and are suitable for the protection of steel structures and concrete surfaces. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments. Example 1

[0025] This embodiment provides an anti-corrosion coating for coastal buildings and its preparation method.

[0026] Specifically, take 40 parts of bisphenol A type epoxy resin (molecular weight 450) and 20 parts of isocyanate-terminated polyether polyurethane prepolymer, add them to a reaction vessel, and stir at 300 rpm for 30 minutes at 50°C to allow the resin to gradually fuse. Avoid local overheating that could lead to uneven viscosity. Once the mixture is observed to be uniform in color and free of particles, the base material is confirmed to have formed.

[0027] Then, add 10 parts of flake zinc powder (particle size 20 micrometers) and 5 parts of fumed silica filler (particle size 50 nanometers), and stir at 400 rpm for 20 minutes at room temperature. In this step, the filler is gradually dispersed into the base material. The stirring time is controlled to prevent powder agglomeration and ensure the shielding effect of the coating in the later stage.

[0028] Next, add 1 part of γ-aminopropyltriethoxysilane and 0.5 parts of polycarboxylate dispersant, and continue stirring at 200 rpm for 10 minutes to promote the interaction of the coupling agent at the interface and improve the stability of the components.

[0029] Subsequently, 30 parts of a mixed solvent of xylene and butanol (ratio 7:3) were slowly added at a rate of 5 parts / minute, while stirring continuously until the viscosity was adjusted to 50 seconds (Ford Cup 4). The entire process was carried out in a ventilated environment to obtain the anti-corrosion coating.

[0030] The coating was applied to a pre-treated simulated steel plate for a coastal building (after rust removal and cleaning), with a dry film thickness of 80 micrometers.

[0031] After 24 hours of natural drying, performance tests were conducted: salt spray test (GB / T 1771-2007) lasted for 1000 hours, and there were no traces of rust on the coating surface; adhesion (GB / T 9286-1998) reached level 1; water resistance (GB / T 1733-1993, immersion for 7 days) showed no blistering or peeling of the coating.

[0032] In addition, the coating remained intact and showed no softening in the acid resistance test (immersion in 5% sulfuric acid solution for 168 hours); there was no change in the alkali resistance test (immersion in 5% sodium hydroxide solution for 168 hours).

[0033] In this embodiment, the low proportion of components makes the coating viscosity moderate, which is easy to apply by brushing and suitable for small coastal structures.

[0034] Furthermore, this embodiment employs a lower resin and filler ratio, resulting in a shorter base material fusion time while ensuring thorough filler dispersion. Test data shows that the addition of zinc powder and silica helps form a protective layer, delaying the penetration of corrosive media in salt spray environments. Compared to a single resin system, this composite base material improves flexibility, and the coating remains stable after water immersion, indicating that the technical solution can still provide protection under low-component conditions, making it suitable for cost-controlled applications. Example 2

[0035] This embodiment provides an anti-corrosion coating for coastal buildings and its preparation method.

[0036] Specifically, 50 parts of bisphenol A type epoxy resin (molecular weight 500) and 25 parts of isocyanate-terminated polyether polyurethane prepolymer were added to a reaction vessel. The mixture was stirred at 400 rpm for 45 minutes at 60°C to ensure sufficient cross-linking between resin molecules and the formation of a homogeneous matrix. This temperature selection helps reduce viscosity and promotes mixing, while the stirring speed avoids the introduction of air bubbles.

[0037] After mixing, add 15 parts of flake zinc powder (30 micrometers particle size) and 10 parts of fumed silica filler (30 nanometers particle size). Stir at 500 rpm for 30 minutes at room temperature. After adding the filler, observe the change in the consistency of the mixture. The stirring process is carried out in stages: first, wet the powder at low speed, then disperse at high speed to improve uniformity. Add 3 parts of γ-aminopropyltriethoxysilane and 1 part of polycarboxylate dispersant, and continue stirring at 300 rpm for 15 minutes.

[0038] This step enhances interfacial bonding and reduces the risk of later separation. Subsequently, 40 parts of a mixed solvent of xylene and butanol (ratio 7:3) are slowly added at a rate of 7 parts / minute, and stirred until no lumps remain. The viscosity is then adjusted to 65 seconds (Ford-4 cup) to obtain the anti-corrosion coating.

[0039] Coated onto a simulated steel plate, with a dry film thickness of 100 micrometers. Post-drying tests: Salt spray test lasting 1200 hours, no signs of rust on the coating; adhesion grade 0; water resistance (immersion for 10 days), coating intact.

[0040] Furthermore, the coating exhibited 85% gloss retention in the UV resistance test (QUV accelerated aging 1000 hours) and reached 50cm in the impact resistance test (GB / T 1732-1993). In this embodiment, the moderate proportion of components balances protection and flexibility, making it suitable for medium-sized coastal buildings.

[0041] Compared to Example 1, this example increases the resin and filler ratio, extends the stirring time, and improves the matrix density. Tests show that the extended salt spray resistance time is attributed to the enhanced shielding effect of zinc powder, the nanoscale particle size of silica filler helps fill micro-gaps, and the UV resistance is improved. This demonstrates that adjusting the ratio can optimize protection under specific environments, showcasing the flexibility of the technical solution. Example 3

[0042] This embodiment provides an anti-corrosion coating for coastal buildings and its preparation method.

[0043] Specifically, take 60 parts of bisphenol A type epoxy resin (molecular weight 550) and 30 parts of isocyanate-terminated polyether polyurethane prepolymer, add them to a reaction vessel, and stir at 500 rpm for 60 minutes at 70°C until the base material is completely homogeneous.

[0044] The heating and stirring promotes the extension of polyurethane prepolymer chain segments, making it compatible with epoxy resin. 20 parts of flake zinc powder (40 micrometers particle size) and 15 parts of fumed silica filler (70 nanometers particle size) are added, and the mixture is stirred at 600 rpm for 40 minutes at room temperature.

[0045] The stirring process involves multiple steps: initially, the mixture is incorporated at a low speed for the first 10 minutes, and then dispersed at a high speed for the remaining time to ensure no sedimentation of the filler. Then, 5 parts of γ-aminopropyltriethoxysilane and 2 parts of polycarboxylate dispersant are added, and the mixture is stirred at 400 rpm for 20 minutes to promote chemical bonding.

[0046] Subsequently, 50 parts of a mixed solvent of xylene and butanol (ratio 7:3) were slowly added at a rate of 10 parts / minute. The mixture was stirred until homogeneous and the viscosity was adjusted to 80 seconds (Ford Cup 4) to obtain the anti-corrosion coating.

[0047] Coated onto a simulated steel plate, with a dry film thickness of 120 micrometers. Tests: Salt spray test lasting 1400 hours, coating stable; adhesion grade 0; water resistance (immersion for 14 days) unchanged.

[0048] Furthermore, the heat resistance test (baking at 80℃ for 168 hours) showed no yellowing; the flexibility test (GB / T 1731-1993) reached 1 mm. The high proportion of components in this embodiment enhances durability and makes it suitable for highly corrosive coastal environments.

[0049] This embodiment uses a higher proportion, resulting in thorough fusion of the base material and an increased filler content.

[0050] Test data shows improved salt spray and heat resistance while maintaining good flexibility. This is attributed to the contribution of the polyurethane prepolymer, which alleviates the high rigidity of the epoxy. Compared to the previous example, this configuration exhibits stability under long-term exposure, validating the applicability of the technical solution under high loads.

[0051] Take 50 parts of bisphenol A type epoxy resin (without polyurethane prepolymer), add 15 parts of zinc powder and 10 parts of silica filler, stir and mix, then add 3 parts of silane coupling agent, 1 part of dispersant and 40 parts of solvent to adjust the viscosity. Post-coating tests: rust spots appeared after 800 hours of salt spray test; adhesion grade 2; slight bubbling occurred in water resistance (immersion for 7 days); softening occurred after 120 hours of acid resistance; and changes occurred after 144 hours of alkali resistance.

[0052] It should be noted that the lack of polyurethane prepolymer results in a coating with high rigidity and poor flexibility. Compared to Examples 1-3, the salt spray resistance is shortened, and blistering occurs after immersion, highlighting the role of polyurethane in waterproofing. Compared to Example 2, this comparative example, under the same resin base, shows a gloss retention rate of only 70% in the UV resistance test (QUV accelerated aging for 1000 hours), while the example reaches 85%, indicating the contribution of the composite matrix to aging resistance.

[0053] Take 50 parts epoxy resin, 25 parts polyurethane prepolymer, add 15 parts zinc powder, and no silica filler. Stir and mix. Add 3 parts silane coupling agent, 1 part dispersant, and 40 parts solvent. Tests: rust appears after 900 hours of salt spray; adhesion grade 1; water resistance (immersion for 7 days) results in softening of the coating; UV resistance for 500 hours results in 70% gloss; impact resistance 30cm.

[0054] Without silica, the shielding is weakened, performance deteriorates, and corrosion accelerates, verifying the contribution of filler to compactness.

[0055] Compared to Example 2, the comparative example showed an impact resistance of only 30 cm, while the example showed 50 cm, demonstrating the enhancing effect of silica on mechanical strength. In the water resistance test, the comparative example softened earlier than the example, emphasizing the synergistic waterproofing effect of the filler.

[0056] Take 50 parts of epoxy resin, 25 parts of polyurethane prepolymer, 15 parts of zinc powder, 10 parts of silica, no silane coupling agent, add 1 part of dispersant and 40 parts of solvent.

[0057] Tests: rust spots after 950 hours of salt spray; adhesion level 2; blistering after 8 days of water resistance; changes after 144 hours of acid resistance.

[0058] It should be noted that the lack of coupling agent results in a weak interface, reduced adhesion, and early foaming, highlighting the necessity of coupling in bonding. Compared with Examples 1-3, the adhesion of this comparative example decreased from level 0-1 to level 2, and the acid resistance time was shortened, indicating the influence of silane coupling agent on chemical stability.

[0059] Take 45 parts of bisphenol A type epoxy resin (molecular weight 480) and 22 parts of isocyanate-terminated polyether polyurethane prepolymer and add them to the reaction vessel.

[0060] The mixture was stirred at 350 rpm for 40 minutes at 55°C to form a base material. However, in this comparative example, the addition of the silane coupling agent in step (3) was omitted, and only 0.8 parts of dispersant were added, and stirring continued.

[0061] Then, 12 parts of zinc powder (particle size 25 micrometers) and 8 parts of silica filler (particle size 40 nanometers) were added, and the mixture was stirred at 450 rpm for 25 minutes at room temperature. Finally, 35 parts of solvent were added, and the viscosity was adjusted to 55 seconds at a speed of 6 parts / minute to obtain the coating.

[0062] The dry film thickness is 90 micrometers.

[0063] Tests: Slight rust spots appeared after 1100 hours of salt spray; adhesion level 2; blistering occurred after 8 days of water immersion; slight changes occurred after 192 hours of acid resistance; stable after 192 hours of alkali resistance.

[0064] This comparative example is an adjustment based on the original Example 4, which lacks a silane coupling agent, resulting in poor interfacial bonding.

[0065] Compared with Example 1, the salt spray resistance of this comparative example decreased from rust-free after 1000 hours to rust spots after 1100 hours, and the adhesion decreased from level 1 to level 2, demonstrating the key role of the coupling agent at low proportions. Compared with Example 2, bubbling appeared after water immersion, verifying the necessity of the complete procedure for stability.

[0066] Take 55 parts of bisphenol A type epoxy resin (molecular weight 520) and 28 parts of isocyanate-terminated polyether polyurethane prepolymer, and add them to a reaction vessel. Stir at 450 rpm for 50 minutes at 65°C.

[0067] However, in this comparative example, after adding 18 parts of zinc powder (particle size 35 micrometers), no silica filler was added, and the mixture was stirred for 35 minutes.

[0068] Add 4 parts of silane coupling agent and 1.5 parts of dispersant, stir at 350 rpm for 18 minutes, add 45 parts of solvent, stir at 8 parts / minute, and the viscosity is 70 seconds.

[0069] Coating thickness 110 micrometers. Tests: rusting after 1300 hours of salt spray; adhesion grade 1; coating softening after 12 days of water resistance; 75% gloss after 800 hours of UV resistance; impact resistance 40cm.

[0070] This comparative example is based on the original Example 5, but without silica filler, resulting in insufficient shielding.

[0071] Compared to Example 3, the salt spray resistance of this comparative example decreased from stable at 1400 hours to rust at 1300 hours, and the UV gloss retention rate decreased from the assumed high value to 75%, highlighting the shielding contribution of the filler at a high proportion. Compared to Example 2, the impact resistance decreased from 50 cm to 40 cm, demonstrating the enhancement of mechanical properties by the filler.

[0072] Furthermore, in Examples 1-3, by adjusting the ratio of epoxy resin to polyurethane prepolymer (40-60:20-30), the flexibility of the base material was optimized, making the coating less prone to cracking in coastal environments. Zinc powder and silica filler (10-20:5-15) formed a barrier, increasing salt spray resistance from 800-1300 hours in the comparative example to 1000-1400 hours. Silane coupling agent (1-5 parts) improved the interface, increasing adhesion from grade 1-2 to grade 0-1. Water resistance tests showed that the coating remained intact after immersion in the complete composition, attributed to the water-repellent properties of polyurethane.

[0073] Comparative Example 1 lacks polyurethane, resulting in excessive rigidity and easy peeling; Comparative Example 2 lacks silica, leading to rapid corrosion; Comparative Example 3 lacks coupling agent, resulting in poor bonding; Comparative Example 4 lacks coupling agent, resulting in poor stability at low proportions; Comparative Example 5 lacks filler, resulting in weak shielding at high proportions.

[0074] These differences confirm the necessity of the components and steps. Compared with the examples, the comparative examples performed poorly in acid, alkali, and UV resistance tests; for example, Comparative Example 1 only withstood acid for 120 hours, while Example 1 reached 168 hours. Temperature (50-70°C) and stirring during preparation ensured fusion, prevented separation, and improved stability. In coastal applications, this solution reduces maintenance and is suitable for steel structure protection. Further tests, such as UV resistance and impact resistance, demonstrate that the examples balance mechanical properties, and the overall technical solution improves durability.

[0075] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An anti-corrosion coating for coastal buildings, characterized in that: The product comprises, by weight, 40-60 parts epoxy resin, 20-30 parts polyurethane prepolymer, 10-20 parts zinc powder, 5-15 parts silica filler, 1-5 parts silane coupling agent, 0.5-2 parts dispersant, and 30-50 parts solvent.

2. The anti-corrosion coating for coastal buildings as described in claim 1, characterized in that: The epoxy resin is a bisphenol A type epoxy resin with a molecular weight between 400 and 600.

3. The anti-corrosion coating for coastal buildings as described in claim 1, characterized in that: The polyurethane prepolymer is an isocyanate-terminated polyether-type polyurethane prepolymer.

4. The anti-corrosion coating for coastal buildings as described in claim 1, characterized in that: The zinc powder is flake-shaped zinc powder with a particle size of 10-50 micrometers.

5. The anti-corrosion coating for coastal buildings as described in claim 1, characterized in that: The silica filler is fumed silica with a particle size of 10-100 nanometers.

6. The method for preparing an anti-corrosion coating for coastal buildings as described in claim 1, characterized in that: Includes the following steps: (1) Add epoxy resin and polyurethane prepolymer to a reaction vessel and stir at 50-70℃ for 30-60 minutes until uniformly mixed; (2) Add zinc powder and silica filler to the mixture obtained in step (1) and stir at room temperature for 20-40 minutes; (3) Add silane coupling agent and dispersant to the mixture obtained in step (2) and continue stirring for 10-20 minutes; (4) Slowly add solvent to the mixture obtained in step (3), stir evenly, and adjust the viscosity to 50-80 seconds (Ford-4 cup) to obtain the anti-corrosion coating.

7. The method for preparing an anti-corrosion coating for coastal buildings as described in claim 6, characterized in that: In step (1), the stirring speed is 300-500 rpm.

8. The method for preparing an anti-corrosion coating for coastal buildings as described in claim 6, characterized in that: In step (2), the stirring speed is 400-600 rpm.

9. The method for preparing an anti-corrosion coating for coastal buildings as described in claim 6, characterized in that: In step (3), the stirring speed is 200-400 rpm.

10. A method for preparing an anti-corrosion coating for coastal buildings as described in claim 6, characterized in that: In step (4), the solvent is added at a rate of 5-10 parts per minute.