Weather-resistant anticorrosive paint for protecting metal tank body and preparation method of weather-resistant anticorrosive paint

Abstract

The invention relates to the technical field of anticorrosive coatings, in particular to a weather-resistant anticorrosive coating for protecting a metal tank body and a preparation method of the weather-resistant anticorrosive coating. Comprising 100 parts of quick-hardening sulphoaluminate cement, 40-55 parts of slaked lime, 50-65 parts of fly ash, 60-80 parts of quartz powder, 10-20 parts of reinforced fibers, 5-10 parts of an air entraining agent, 10-20 parts of a foam stabilizer, 60-80 parts of waterborne epoxy resin, 3-5 parts of a polycarboxylic acid high-performance water reducing agent, 4-8 parts of calcium formate, 65-85 parts of water, 15-25 parts of a quinoline-containing POSS derivative, 1-2 parts of a curing agent and 0.5-1 part of a silane coupling agent. The quinoline-containing POSS derivative is prepared from octacarboxyl POSS and 3, 4-diaminoquinoline through a reaction of octacarboxyl POSS and 3, 4-diaminoquinoline. According to the preparation method, octacarboxyl POSS and 3, 4-diaminoquinoline are subjected to acylation reaction for the first time to prepare the quinoline-containing POSS derivative with a cage-shaped POSS inner core and quinolyl rigid outer arm structure, the quinoline-containing POSS derivative is used as an anti-corrosion synergist to be applied to a coating, and the weather resistance and corrosion resistance of the coating are improved through triple mechanisms of physical barrier, chemical passivation and microbial inhibition.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-corrosion coatings, and in particular to a weather-resistant anti-corrosion coating for protecting metal tanks and a preparation method thereof. Background Art

[0002] Metal oil tanks are large, regularly shaped containers used to store oil, most often made of steel. Reportedly, over 90% of fuel oil is stored in metal tanks. However, long-term exposure to complex environments such as moisture, salt spray, temperature fluctuations, and chemical corrosion can lead to severe electrochemical corrosion and physical aging on the surface of metal tanks, severely shortening their service life and potentially causing safety incidents such as leaks and explosions. Furthermore, due to the long-term sealing of metal tanks and the constant contact between the tank bottom and the ground, large numbers of sulfate-reducing bacteria (SRB) can easily grow on the inner walls and bottom of the tanks, releasing hydrogen sulfide gas, further exacerbating corrosion.

[0003] Based on the above, how to improve the anti-corrosion performance of metal tanks has always been one of the research hotspots in the field of coatings. For example, the invention patent with announcement number CN102674776B uses silicate cement, self-crosslinking acrylic copolymer emulsion, UEA calcium sulfoaluminate expansion agent, polycarboxylic acid high-performance water reducer and other compound inorganic-based metal oil tank anti-corrosion materials; for example, the invention patent with announcement number CN110408314B prepares conductive polymers and polyfluorosilanized polymers. The conductive polymers contain a large number of hydroxyl groups, which can react with the isocyanate groups in toluene diisocyanate. At the same time, the polyfluorosilanized polymers contain a large number of carboxylic acid groups, which can also react with isocyanate groups. As a result, the conductive polymer chains and the polyfluorosilanized polymer chains are polymerized, cross-linked and cured through toluene diisocyanate to form a network structure, and conductive graphite powder is interspersed in the network structure to form a conductive path between adjacent conductive polymers.

[0004] However, the above-mentioned anti-corrosion coatings still need to be improved in terms of their ability to resist microbial corrosion and their long-term stability in hydrogen sulfide environments. In particular, in the long-term closed environment inside metal oil tanks and at the bottom of the tank, the existing coatings are easily ineffective due to corrosion from hydrogen sulfide released by sulfate-reducing bacteria over a long period of time. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to propose a weather-resistant and anti-corrosion coating for metal tank protection and a preparation method thereof, and to utilize the amide bond reaction of octacarboxyl POSS and 3,4-diaminoquinoline to generate a quinoline-containing POSS derivative, which is then applied to the anti-corrosion coating, thereby significantly improving the weather-resistant and anti-corrosion performance of the coating through the triple mechanisms of chemical passivation, physical barrier and biological inhibition.

[0006] Based on the above objectives, the present invention provides a weather-resistant and anti-corrosion coating for metal tank protection, which comprises, by mass, 100 parts of fast-hardening sulphoaluminate cement, 40-55 parts of slaked lime, 50-65 parts of fly ash, 60-80 parts of quartz powder, 10-20 parts of reinforcing fiber, 5-10 parts of air entraining agent, 10-20 parts of foam stabilizer, 60-80 parts of water-based epoxy resin, 3-5 parts of polycarboxylic acid high-performance water reducer, 4-8 parts of calcium formate, 65-85 parts of water, 15-25 parts of quinoline-containing POSS derivative, 1-2 parts of curing agent, and 0.5-1 part of silane coupling agent.

[0007] The quinoline-containing POSS derivative is prepared by reacting octacarboxyl POSS with 3,4-diaminoquinoline.

[0008] Furthermore, the preparation method of the quinoline-containing POSS derivative comprises the following steps:

[0009] A1: Add octacarboxyl POSS to tetrahydrofuran solvent and stir until completely dissolved to obtain a clear POSS solution;

[0010] A2: Heat the POSS solution to 55-60°C, add 3,4-diaminoquinoline, and stir for 20-30 minutes. Then, add EDC·HCl, and stir at 40-60°C for 6-12 hours. Remove the solvent by rotary evaporation, and vacuum dry for 12 hours to obtain a quinoline-containing POSS derivative.

[0011] Furthermore, the usage ratio of the octacarboxyl POSS, tetrahydrofuran solvent, 3,4-diaminoquinoline, and EDC·HCl is 1 mmol:30 mL:8 mmol:(20-30) mg.

[0012] Furthermore, the particle size of the quartz powder is ≤200 mesh.

[0013] Furthermore, the reinforcing fiber is selected from one of basalt fiber, PE fiber and glass fiber.

[0014] Furthermore, the air entraining agent is selected from one of sodium bicarbonate, ammonium bicarbonate, sodium carbonate and potassium carbonate.

[0015] Furthermore, the foam stabilizer is selected from one of sodium α-olefin sulfonate, polyvinyl alcohol, polyvinyl pyrrolidone, casein, and soy protein.

[0016] Furthermore, the curing agent is selected from one of ethylenediamine, hexamethylenediamine, diethylenetriamine and triethylenetetramine.

[0017] Furthermore, the silane coupling agent is selected from one of KH550 silane coupling agent, KH602 silane coupling agent and KH792 silane coupling agent.

[0018] The present invention further provides a method for preparing the above-mentioned weather-resistant anti-corrosion coating for metal tank protection, comprising the following steps:

[0019] S1: At room temperature, rapidly hardening sulphoaluminate cement, slaked lime, fly ash, quartz powder, reinforcing fiber, air entraining agent, and foam stabilizer are uniformly mixed to obtain composition A;

[0020] S2: At room temperature, a water-based epoxy resin, a polycarboxylic acid high-performance water-reducing agent, calcium formate, and water are uniformly mixed to obtain a composition B;

[0021] S3: at room temperature, uniformly mixing the quinoline-containing POSS derivative, the curing agent, and the silane coupling agent to obtain a composition C;

[0022] S4: At 30-50° C., the composition A, the composition B, and the composition C are uniformly mixed to obtain the weather-resistant anti-corrosion coating for protecting the metal tank.

[0023] Beneficial effects of the present invention:

[0024] This invention is the first to use octacarboxyl POSS to react with 3,4-diaminoquinoline to undergo an acylation reaction to prepare a quinoline-containing POSS derivative with a "cage-like POSS core and quinoline-based rigid outer arm" structure, and use it as an anti-corrosion enhancer in coatings. It significantly improves the weathering and anti-corrosion properties of the coating through the triple mechanisms of physical barrier, chemical passivation and microbial inhibition.

[0025] First, the quinoline-containing POSS derivatives undergo a cross-linking reaction with the water-based epoxy resin, so that the quinoline-containing POSS derivatives are uniformly intercalated and dispersed in the coating body to form a dense three-dimensional network barrier. At the same time, the POSS skeleton in the quinoline-containing POSS derivatives can pass through, significantly inhibiting the corrosion of H2S gas and delaying the formation of Cl - The penetration effect;

[0026] Secondly, the nitrogen atom on the pyridine ring in the quinoline-containing POSS derivatives binds to Fe via a lone pair of electrons. 2+ / Fe 3+ A coordinated reaction occurs to form a dense chemical passivation film at the metal / coating interface, inhibiting the anodic reaction, reducing the corrosion current density, and blocking direct contact between the metal tank and H2S gas;

[0027] Finally, the unique multivalent structure of "one cage and eight quinolines" of quinoline-containing POSS derivatives makes its antibacterial rate against sulfate-reducing bacteria (SRB) as high as 99.8%, thereby avoiding the corrosion of metal tanks by H2S produced by SRB metabolism. When the derivatives come into contact with SRB, the multiple quinoline rings in their structure can simultaneously target and bind to multiple sites on the bacterial surface, forming a synergistic effect similar to "molecular clamps". This may be the main reason why quinoline-containing POSS derivatives exhibit higher sulfate-reducing bacteria inhibition rates. At the same time, the nanoscale cage structure of POSS also helps to improve the dispersibility and stability of the quinoline group. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0029] The quinoline-containing POSS derivatives used in the following examples are prepared by reacting octacarboxyl POSS with 3,4-diaminoquinoline. The preparation method comprises the following steps:

[0030] A1: Add octacarboxyl POSS to tetrahydrofuran solvent and stir until completely dissolved to obtain a clear POSS solution;

[0031] A2: Heat the POSS solution to 60°C, add 3,4-diaminoquinoline, and stir for 30 minutes. Then, add EDC·HCl and stir at 55°C for 12 hours. Remove the solvent by rotary evaporation and dry in vacuo for 12 hours to obtain the quinoline-containing POSS derivative.

[0032] The usage ratio of the octacarboxyl POSS, tetrahydrofuran solvent, 3,4-diaminoquinoline and EDC·HCl is 1 mmol:30 mL:8 mmol:25 mg.

[0033] Example 1

[0034] A weather-resistant and anti-corrosion coating for protecting metal tanks, comprising, by mass, 100 parts of fast-hardening sulphoaluminate cement, 40 parts of slaked lime, 50 parts of fly ash, 60 parts of quartz powder with a particle size of ≤200 mesh, 10 parts of basalt fiber, 5 parts of sodium bicarbonate, 10 parts of polyvinyl alcohol, 60 parts of water-based epoxy resin, 3 parts of polycarboxylic acid high-performance water reducer, 4 parts of calcium formate, 65 parts of water, 15 parts of a POSS derivative containing quinoline, 1 part of ethylenediamine, and 0.5 part of a KH550 silane coupling agent.

[0035] A method for preparing a weather-resistant and anti-corrosion coating for metal tank protection comprises the following steps:

[0036] S1: At room temperature, rapidly hardening sulfoaluminate cement, slaked lime, fly ash with a particle size of ≤200 mesh, quartz powder, basalt fiber, sodium bicarbonate, and polyvinyl alcohol are uniformly mixed to obtain composition A;

[0037] S2: At room temperature, a water-based epoxy resin, a polycarboxylic acid high-performance water-reducing agent, calcium formate, and water are uniformly mixed to obtain a composition B;

[0038] S3: at room temperature, uniformly mixing the quinoline-containing POSS derivative, ethylenediamine, and KH550 silane coupling agent to obtain a composition C;

[0039] S4: At 40° C., the composition A, the composition B, and the composition C are uniformly mixed to obtain the weather-resistant anti-corrosion coating for protecting the metal tank.

[0040] Example 2

[0041] A weather-resistant and anti-corrosion coating for protecting metal tanks, comprising, by mass, 100 parts of fast-hardening sulphoaluminate cement, 55 parts of slaked lime, 65 parts of fly ash, 80 parts of quartz powder with a particle size of ≤200 mesh, 20 parts of PE fiber, 10 parts of ammonium bicarbonate, 20 parts of polyvinyl pyrrolidone, 80 parts of water-based epoxy resin, 5 parts of polycarboxylic acid high-performance water reducer, 8 parts of calcium formate, 85 parts of water, 25 parts of a POSS derivative containing quinoline, 2 parts of diethylenetriamine, and 1 part of a KH602 silane coupling agent.

[0042] A method for preparing a weather-resistant and anti-corrosion coating for metal tank protection comprises the following steps:

[0043] S1: At room temperature, rapidly hardening sulphoaluminate cement, slaked lime, fly ash, quartz powder with a particle size of ≤200 mesh, PE fiber, ammonium bicarbonate, and polyvinyl pyrrolidone are uniformly mixed to obtain a composition A;

[0044] S2: At room temperature, a water-based epoxy resin, a polycarboxylic acid high-performance water-reducing agent, calcium formate, and water are uniformly mixed to obtain a composition B;

[0045] S3: at room temperature, uniformly mixing the quinoline-containing POSS derivative, diethylenetriamine, and KH602 silane coupling agent to obtain composition C;

[0046] S4: At 50° C., the composition A, the composition B, and the composition C are uniformly mixed to obtain the weather-resistant anti-corrosion coating for protecting the metal tank.

[0047] The comparative example is the same as Example 1, except that the POSS derivative containing quinoline in Example 1 is replaced by a mixture of octacarboxyl POSS and 3,4-diaminoquinoline in a molar ratio of 1:8.

[0048] The corresponding samples were prepared by coating the surface of 10cm×10cm Q235 steel plate substrates of Examples 1-2 and the comparative example. The samples were cured at 60°C for 5h and naturally cured at room temperature for 7d. The coating thickness was controlled at 1mm, and performance tests were carried out.

[0049] The alkali resistance of the anti-corrosion coatings prepared in Examples 1-2 and the comparative example was measured according to GB / T 9274-1988; the alkaline condition was 5% NaOH, and the test temperature was 25°C.

[0050] EIS impedance: The coating was subjected to electrochemical impedance spectroscopy (EIS) testing using an electrochemical workstation (CHI660E, Shanghai Chenhua Instrument Co., Ltd.) using a conventional three-electrode system. The working electrode was a Q235 steel block with an exposed area of ​​1 cm × 1 cm, the counter electrode was a platinum sheet, and the reference electrode was a saturated calomel electrode. The coating was immersed in a simulated solution containing 3.5 wt% NaCl for 1 week, and then the electrochemical impedance spectroscopy (EIS) test was performed. The test frequency range was 10 -2 ~10 5 Hz, record the impedance modulus (|Z|, Ω·cm) in the low frequency region (0.01Hz) 2 ).

[0051] Chemical resistance: The coating was immersed in a 10 wt% H2S solution for 30 days, and the weight loss rate (%) was calculated.

[0052] The antibacterial properties of the weather-resistant and anticorrosive coatings prepared in Examples 1-2 and Comparative Example 1 were determined in accordance with HG-T 3950-2007 "Antibacterial Coatings". The test strain was sulfate-reducing bacteria, wherein the broth medium (NB) formula for sulfate-reducing bacteria was: 5.0 g beef extract, 10.0 g peptone, 2.5 g sodium chloride, 5.0 g sodium sulfate, 1000 mL distilled water, pH = 7.0, and the culture medium was broth medium (NB) / physiological saline solution, and the culture medium concentration was 1 / 100.

[0053] The test results are shown in the following table:

[0054]

[0055] As can be seen from the above table, the present invention utilizes quinoline-containing POSS derivatives to effectively improve the acid and alkali resistance and anti-corrosion performance of the anti-corrosion coating. At the same time, it also exhibits excellent antibacterial properties against sulfate-reducing bacteria, thereby preventing the growth of sulfate-reducing bacteria in the long-term closed environment inside the metal oil tank and at the bottom of the tank body, thereby preventing the corrosion effect of hydrogen sulfide gas released by the metabolism of sulfate-reducing bacteria.

[0056] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0057] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A weather-resistant and anti-corrosion coating for metal tank protection, characterized in that: The composition is composed of 100 parts by mass of fast-hardening sulphoaluminate cement, 40-55 parts of slaked lime, 50-65 parts of fly ash, 60-80 parts of quartz powder, 10-20 parts of reinforcing fiber, 5-10 parts of air entraining agent, 10-20 parts of foam stabilizer, 60-80 parts of water-based epoxy resin, 3-5 parts of polycarboxylic acid high-performance water-reducing agent, 4-8 parts of calcium formate, 65-85 parts of water, 15-25 parts of POSS derivative containing quinoline, 1-2 parts of curing agent and 0.5-1 part of silane coupling agent. The quinoline-containing POSS derivative is prepared by reacting octacarboxyl POSS with 3,4-diaminoquinoline.

2. The weather-resistant and anti-corrosion coating for metal tank protection according to claim 1 is characterized in that: The preparation method of the quinoline-containing POSS derivative comprises the following steps: A1: Add octacarboxyl POSS to tetrahydrofuran solvent and stir until completely dissolved to obtain a clear POSS solution; A2: Heat the POSS solution to 55-60°C, add 3,4-diaminoquinoline, and stir for 20-30 minutes. Then, add EDC·HCl, and stir at 40-60°C for 6-12 hours. Remove the solvent by rotary evaporation, and vacuum dry for 12 hours to obtain a quinoline-containing POSS derivative.

3. The weather-resistant and anti-corrosion coating for metal tank protection according to claim 2, characterized in that: The usage ratio of the octacarboxyl POSS, tetrahydrofuran solvent, 3,4-diaminoquinoline and EDC·HCl is 1 mmol:30 mL:8 mmol:(20-30) mg.

4. The weather-resistant and anti-corrosion coating for metal tank protection according to claim 1, characterized in that: The particle size of the quartz powder is ≤200 meshes.

5. The weather-resistant and anti-corrosion coating for metal tank protection according to claim 1, characterized in that: The reinforcing fiber is selected from one of basalt fiber, PE fiber and glass fiber.

6. The weather-resistant and anti-corrosion coating for metal tank protection according to claim 1, characterized in that: The air entraining agent is selected from one of sodium bicarbonate, ammonium bicarbonate, sodium carbonate and potassium carbonate.

7. The weather-resistant and anti-corrosion coating for metal tank protection according to claim 1, characterized in that: The foam stabilizer is selected from one of sodium α-olefin sulfonate, polyvinyl alcohol, polyvinyl pyrrolidone, casein and soy protein.

8. The weather-resistant and anti-corrosion coating for metal tank protection according to claim 1, characterized in that: The curing agent is selected from one of ethylenediamine, hexamethylenediamine, diethylenetriamine and triethylenetetramine.

9. The weather-resistant and anti-corrosion coating for metal tank protection according to claim 1, characterized in that: The silane coupling agent is selected from one of KH550 silane coupling agent, KH602 silane coupling agent and KH792 silane coupling agent.

10. A method for preparing a weather-resistant and anti-corrosion coating for metal tank protection according to any one of claims 1 to 9, characterized in that: The steps include: S1: At room temperature, rapidly hardening sulphoaluminate cement, slaked lime, fly ash, quartz powder, reinforcing fiber, air entraining agent, and foam stabilizer are uniformly mixed to obtain composition A; S2: At room temperature, a water-based epoxy resin, a polycarboxylic acid high-performance water-reducing agent, calcium formate, and water are uniformly mixed to obtain a composition B; S3: at room temperature, uniformly mixing the quinoline-containing POSS derivative, the curing agent, and the silane coupling agent to obtain a composition C; S4: At 30-50° C., the composition A, the composition B, and the composition C are mixed evenly to obtain the weather-resistant anti-corrosion coating for protecting the metal tank.

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