A weather-resistant and corrosion-resistant coating for the protection of metal tanks and its preparation method

Abstract

This invention relates to the field of anti-corrosion coating technology, and more particularly to a weather-resistant anti-corrosion coating for metal tank protection and its preparation method. By weight, it comprises: 100 parts rapid-hardening sulfoaluminate cement, 40-55 parts quicklime, 50-65 parts fly ash, 60-80 parts quartz powder, 10-20 parts reinforcing fiber, 5-10 parts air-entraining agent, 10-20 parts foam stabilizer, 60-80 parts waterborne epoxy resin, 3-5 parts polycarboxylate high-performance water-reducing agent, 4-8 parts calcium formate, 65-85 parts water, 15-25 parts quinoline-containing POSS derivative, 1-2 parts curing agent, and 0.5-1 parts silane coupling agent; wherein the quinoline-containing POSS derivative is prepared by reacting octacarboxylated POSS with 3,4-diaminoquinoline. This invention is the first to utilize the acylation reaction between octacarboxylated POSS and 3,4-diaminoquinoline to prepare a quinoline-containing POSS derivative with a structure of "cage-like POSS core and quinoline-based rigid outer arm". This derivative is then used as an anti-corrosion synergist in coatings, improving the weather resistance and anti-corrosion performance of the coating through a triple mechanism of physical barrier, chemical passivation and microbial inhibition.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating technology, and in particular to a weather-resistant anti-corrosion coating for the protection of metal tanks and its preparation method. Background Technology

[0002] Metal oil tanks are large, regularly shaped containers used to store oil products. Most are made of steel, and it's reported that over 90% of fuel oil is stored in metal tanks. However, metal tanks are exposed to complex environments such as humidity, salt spray, temperature fluctuations, and chemical corrosion for extended periods, leading to severe electrochemical corrosion and physical aging on their surfaces. This significantly impacts their service life and can potentially cause leaks, explosions, and other safety accidents. Furthermore, due to the long-term sealing of metal oil tanks and their constant contact with the ground at the bottom, large amounts of sulfate-reducing bacteria easily grow on the inner walls and bottom of the tanks, releasing hydrogen sulfide gas and further exacerbating corrosion.

[0003] Based on the above, improving the corrosion resistance of metal tanks has always been a research hotspot in the coatings field. For example, the invention patent with announcement number CN102674776B uses silicate cement, self-crosslinking acrylate copolymer emulsion, UEA calcium sulfoaluminate expanding agent, polycarboxylic acid high-performance water-reducing agent, etc. to formulate inorganic-based metal oil tank corrosion protection materials. Another invention patent with announcement number CN110408314B prepares conductive polymers and polyfluorosilane 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 polyfluorosilane polymers contain a large number of carboxylic acid groups, which can also react with the isocyanate groups. This allows the conductive polymer chains and polyfluorosilane polymer chains to polymerize, crosslink, and solidify through toluene diisocyanate to form a network structure. Conductive graphite powder is then interspersed in the network structure, forming conductive pathways between adjacent conductive polymers.

[0004] However, the anti-corrosion coatings mentioned above still need to be improved in terms of their resistance to microbial corrosion and their long-term stability in hydrogen sulfide environments. In particular, in the long-term closed environment inside and at the bottom of metal oil tanks, the existing coatings are prone to failure due to the long-term release of hydrogen sulfide by sulfate-reducing bacteria. Summary of the Invention

[0005] In view of this, the purpose of this invention is to propose a weather-resistant and anti-corrosion coating for the protection of metal tanks and its preparation method. The coating utilizes the reaction of octacarboxylated POSS with the amide bond of 3,4-diaminoquinoline to generate a quinoline-containing POSS derivative, which is then applied to the anti-corrosion coating. Through a triple mechanism of chemical passivation, physical barrier and biological inhibition, the weather resistance and anti-corrosion performance of the coating are significantly improved.

[0006] To achieve the above objectives, the present invention provides a weather-resistant and anti-corrosion coating for the protection of metal tanks, comprising, by weight: 100 parts of rapid-hardening sulfoaluminate cement, 40-55 parts of quicklime, 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 waterborne epoxy resin, 3-5 parts of polycarboxylate high-performance water-reducing agent, 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 parts of silane coupling agent;

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

[0008] Furthermore, the method for preparing the quinoline-containing POSS derivative includes the following steps:

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

[0010] A2: Heat the POSS solution to 55-60℃, add 3,4-diaminoquinoline, stir for 20-30 min, add EDC·HCl, and then stir at 40-60℃ for 6-12 h. Remove the solvent by rotary evaporation, and then dry under vacuum for 12 h to obtain the quinoline-containing POSS derivative.

[0011] Furthermore, the ratio of the amounts of octacarboxylated 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 gasifying 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-alkenyl sulfonate, polyvinyl alcohol, polyvinylpyrrolidone, 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 and anti-corrosion coating for metal tank protection, comprising the following steps:

[0019] S1: At room temperature, rapid-hardening sulfoaluminate cement, quicklime, fly ash, quartz powder, reinforcing fiber, air-entraining agent and foam stabilizer are mixed evenly to obtain composition A;

[0020] S2: At room temperature, waterborne epoxy resin, polycarboxylate high-performance water-reducing agent, calcium formate and water are mixed evenly to obtain composition B;

[0021] S3: At room temperature, POSS derivatives containing quinoline, curing agents, and silane coupling agents are mixed evenly to obtain composition C;

[0022] S4: At 30-50℃, after uniformly mixing composition A, composition B and composition C, the weather-resistant and anti-corrosion coating for protecting metal tanks is obtained.

[0023] The beneficial effects of this invention are:

[0024] This invention is the first to utilize the acylation reaction between octacarboxylated POSS and 3,4-diaminoquinoline to prepare a quinoline-containing POSS derivative with a structure of "cage-like POSS core and quinoline-based rigid outer arm". This derivative is then used as an anti-corrosion synergist in coatings, significantly improving the weather resistance and anti-corrosion performance of the coating through a triple mechanism of physical barrier, chemical passivation and microbial inhibition.

[0025] First, the quinoline-containing POSS derivative undergoes a cross-linking reaction with waterborne epoxy resin, resulting in a uniformly dispersed and integrated composition within the coating, forming a dense three-dimensional network barrier. Simultaneously, the POSS framework within the quinoline-containing POSS derivative significantly inhibits the corrosive effects of H2S gas and delays the degradation of Cl-. - The effect of osmosis;

[0026] Secondly, the nitrogen atom on the pyridine ring in quinoline POSS derivatives interacts with Fe through lone pair electrons. 2+ / Fe 3+ A complex reaction occurs, forming a dense chemical passivation film at the metal / coating interface, which inhibits the anodic reaction, reduces the corrosion current density, and blocks the direct contact between the metal tank and H2S gas.

[0027] Finally, the unique "one-cage octaquinoline" multivalent structure of the quinoline-containing POSS derivative enables it to achieve an antibacterial rate of up to 99.8% against sulfate-reducing bacteria (SRB), thereby avoiding the corrosive effect of H2S produced by SRB metabolism on the metal can. When the derivative comes into contact with SRB, the multiple quinoline rings in its 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 the quinoline-containing POSS derivative exhibits a higher sulfate-reducing bacteria inhibition rate. At the same time, the nanoscale cage structure of POSS also helps to improve the dispersibility and stability of the quinoline group. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

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

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

[0031] A2: Heat the POSS solution to 60℃, add 3,4-diaminoquinoline, stir for 30 min, add EDC·HCl, stir at 55℃ for 12 h, remove the solvent by rotary evaporation, and vacuum dry for 12 h to obtain the quinoline-containing POSS derivative.

[0032] The ratio of the amounts of octacarboxylated 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 weight: 100 parts rapid-hardening sulfoaluminate cement, 40 parts quicklime, 50 parts fly ash, 60 parts quartz powder with a particle size ≤200 mesh, 10 parts basalt fiber, 5 parts sodium bicarbonate, 10 parts polyvinyl alcohol, 60 parts waterborne epoxy resin, 3 parts polycarboxylate high-performance water-reducing agent, 4 parts calcium formate, 65 parts water, 15 parts quinoline-containing POSS derivative, 1 part ethylenediamine, and 0.5 parts KH550 silane coupling agent.

[0035] A method for preparing a weather-resistant and corrosion-resistant coating for protecting metal tanks includes the following steps:

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

[0037] S2: At room temperature, waterborne epoxy resin, polycarboxylate high-performance water-reducing agent, calcium formate and water are mixed evenly to obtain composition B;

[0038] S3: At room temperature, POSS derivatives containing quinoline, ethylenediamine, and KH550 silane coupling agent are mixed evenly to obtain composition C;

[0039] S4: At 40°C, after uniformly mixing composition A, composition B, and composition C, the weather-resistant and anti-corrosion coating for protecting the metal tank is obtained.

[0040] Example 2

[0041] A weather-resistant and anti-corrosion coating for protecting metal tanks, comprising, by weight parts: 100 parts rapid-hardening sulfoaluminate cement, 55 parts quicklime, 65 parts fly ash, 80 parts quartz powder with a particle size ≤200 mesh, 20 parts PE fiber, 10 parts ammonium bicarbonate, 20 parts polyvinylpyrrolidone, 80 parts waterborne epoxy resin, 5 parts polycarboxylate high-performance water-reducing agent, 8 parts calcium formate, 85 parts water, 25 parts quinoline-containing POSS derivative, 2 parts diethylenetriamine, and 1 part KH602 silane coupling agent.

[0042] A method for preparing a weather-resistant and corrosion-resistant coating for protecting metal tanks includes the following steps:

[0043] S1: At room temperature, rapid-hardening sulfoaluminate cement, quicklime, fly ash, quartz powder with a particle size ≤200 mesh, PE fiber, ammonium bicarbonate, and polyvinylpyrrolidone are mixed evenly to obtain composition A;

[0044] S2: At room temperature, waterborne epoxy resin, polycarboxylate high-performance water-reducing agent, calcium formate and water are mixed evenly to obtain composition B;

[0045] S3: At room temperature, POSS derivatives containing quinoline, diethylenetriamine, and KH602 silane coupling agent are mixed evenly to obtain composition C;

[0046] S4: At 50°C, after uniformly mixing composition A, composition B, and composition C, the weather-resistant and anti-corrosion coating for protecting metal tanks is obtained.

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

[0048] Samples were prepared by coating the surface of a 10cm×10cm Q235 steel plate substrate in Examples 1-2 and the comparative example. The samples were cured at 60℃ for 5 hours and then naturally cured at room temperature for 7 days. The coating thickness was controlled at 1mm, and performance tests were performed.

[0049] The alkali resistance of the anti-corrosion coatings prepared in Examples 1-2 and the comparative examples was determined according to GB / T 9274-1988; the alkaline conditions were 5% NaOH and the test temperature was 25℃.

[0050] EIS Impedance: Electrochemical impedance spectroscopy (EIS) tests were performed on the coating using an electrochemical workstation (CHI660E, Shanghai Chenhua Instrument Co., Ltd.) employing a traditional 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 one week before EIS testing was performed. The test frequency range was 10 Hz. -2 ~10 5 Hz, record the impedance magnitude (|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 anti-corrosion coatings prepared in Examples 1-2 and Comparative Example 1 were determined according to the standard HG-T 3950-2007 "Antibacterial Coatings". The tested bacteria were sulfate-reducing bacteria. The broth culture medium (NB) formula for sulfate-reducing bacteria was as follows: 5.0g beef extract, 10.0g peptone, 2.5g sodium chloride, 5.0g sodium sulfate, 1000mL distilled water, pH=7.0. The culture medium was broth culture medium (NB) / physiological saline solution with a concentration of 1 / 100.

[0053] The experimental results are shown in the table below:

[0054]

[0055] As shown in the table above, the present invention utilizes quinoline-containing POSS derivatives to effectively improve the acid and alkali resistance and anti-corrosion performance of anti-corrosion coatings. At the same time, it also exhibits excellent antibacterial properties against sulfate-reducing bacteria, which can prevent the growth of sulfate-reducing bacteria in the long-term closed environment inside and at the bottom of metal oil tanks, thereby preventing the corrosive 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 exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0057] This 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 this invention should be included within the scope of protection of this invention.

Claims

1. A weather-resistant anticorrosive coating for metal can bodies, characterized by, By mass parts, including: fast hard sulphoaluminate cement 100 parts, slaked lime 40-55 parts, fly ash 50-65 parts, quartz powder 60-80 parts, reinforcing fiber 10-20 parts, air-entraining agent 5-10 parts, foam stabilizer 10-20 parts, water-based epoxy resin 60-80 parts, polycarboxylic acid high-performance water reducing agent 3-5 parts, calcium formate 4-8 parts, water 65-85 parts, quinoline-containing POSS derivative 15-25 parts, curing agent 1-2 parts, silane coupling agent 0.5-1 parts; The quinoline-containing POSS derivative is prepared by reacting octocarboxylic POSS with 3,4-diaminoquinoline; The preparation method of the quinoline-containing POSS derivative comprises the following steps: A1: Octocarboxylic POSS is added to a tetrahydrofuran solvent and stirred until completely dissolved to obtain a clear POSS solution; A2: The POSS solution is heated to 55-60°C, 3,4-diaminoquinoline is added, and after stirring for 20-30 min, EDC·HCl is added, and then stirring and reaction are carried out at 40-60°C for 6-12 h, the solvent is removed by rotary evaporation, and vacuum drying is carried out for 12 h to obtain the quinoline-containing POSS derivative; The amount ratio of the octocarboxylic POSS, tetrahydrofuran solvent, 3,4-diaminoquinoline, and EDC·HCl is 1 mmol:30 mL:8 mmol:(20-30) mg.

2. The weather resistant anticorrosive coating for metal can body protection according to claim 1, characterized by, The particle size of the quartz powder is ≤200 mesh.

3. The weather resistant anticorrosive coating for metal can body protection according to claim 1, characterized by, The reinforcing fiber is selected from one of basalt fiber, PE fiber, and glass fiber.

4. The weather resistant anticorrosive coating for metal can body protection according to claim 1, characterized by, The air-entraining agent is selected from one of sodium bicarbonate, ammonium bicarbonate, sodium carbonate, and potassium carbonate.

5. The weather resistant anticorrosive coating for metal can body protection according to claim 1, characterized by, The foam stabilizer is selected from one of α-alkenyl sulfonate sodium, polyvinyl alcohol, polyvinylpyrrolidone, casein, and soybean protein.

6. The weather resistant anticorrosive coating for metal can body protection according to claim 1, characterized by, The curing agent is selected from one of ethylenediamine, hexamethylenediamine, diethylenetriamine, and triethylenetetramine.

7. The weather resistant anticorrosive coating for metal can body protection according to claim 1, characterized by, The silane coupling agent is selected from one of KH550 silane coupling agent, KH602 silane coupling agent, and KH792 silane coupling agent.

8. A process for the production of a weather-resistant anticorrosive coating for metal cans according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: S1: At room temperature, fast hard 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, water-based epoxy resin, polycarboxylic acid high-performance water reducing agent, calcium formate, and water are uniformly mixed to obtain composition B; S3: At room temperature, quinoline-containing POSS derivative, curing agent, and silane coupling agent are uniformly mixed to obtain composition C; S4: At 30-50°C, composition A, composition B, and composition C are uniformly mixed to obtain the weather-resistant anticorrosive coating for metal tank body protection.

Images