An anti-corrosion coating for coastal concrete structures and its preparation method

Abstract

The present invention provides a preparation method of an anti-corrosion coating for a coastal concrete structure. The raw materials include a bactericide, a leveling agent, a curing agent, a film-forming agent and water. The bactericide includes potassium hypochlorite, methylene bisthiocyanate and tetrakis(hydroxymethyl) phosphonium sulfate. The film-forming agent includes glass fiber, graphene fiber, epoxy resin and a solvent. The anti-corrosion coating of the present invention inhibits sulfate-reducing bacteria, thiobacilli and Fusarium fungi, prevents the generation of acidic substances, and avoids the reaction between acidic substances and alkaline substances, thereby preventing damage to the concrete structure. The reasonable proportioning of the raw materials of the anti-corrosion coating of the present invention forms a dense protective barrier, further improving the anti-corrosion performance of the coating.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete anti-corrosion, and particularly to a preparation method of an anti-corrosion coating for coastal concrete structures. Background Art

[0002] In the marine atmospheric corrosion environment, carbonation of concrete and chloride ion erosion of steel bars are the main reasons for the deterioration and failure of marine reinforced concrete.

[0003] Concrete microbial corrosion is also an important factor affecting the strength of concrete. Sulfate-reducing bacteria reduce sulfates or organic sulfur in concrete to hydrogen sulfide, causing changes in the environmental pH. Hydrogen sulfide is oxidized by sulfur-oxidizing bacteria to form biogenic sulfuric acid. Biogenic sulfuric acid will react with alkaline substances in concrete to form gypsum, and the gypsum will continue to react with the excess tricalcium aluminate in concrete to further generate an expansive product, ettringite, resulting in concrete cracking. At the same time, during the above reaction process, the calcium silicate hydrate (C-S-H) gel in concrete will decompose, generating insoluble colloids, leading to a decrease in the strength of concrete. Summary of the Invention

[0004] In view of this, the present invention provides a preparation method of an anti-corrosion coating for coastal concrete structures to solve the above problems.

[0005] The technical solution of the present invention is realized as follows:

[0006] An anti-corrosion coating for coastal concrete structures, the raw materials include a bactericide, a leveling agent, a curing agent, a film-forming agent and water. The bactericide includes potassium hypochlorite, methylene bisthiocyanate and tetrakis(hydroxymethyl) phosphonium sulfate. The film-forming agent includes glass fiber, graphene fiber, epoxy resin and a solvent.

[0007] Further, the solvent in the film-forming agent is xylene and ethyl acetate with a volume ratio of 2-4:1-1.5, and the epoxy resin is bisphenol A epoxy resin.

[0008] Further, the preparation method of the film-forming agent is to mix bisphenol A epoxy resin and a silane coupling agent and ball-mill for 50-70 min, and then add glass fiber, graphene fiber and the solvent and ball-mill for 30-40 min.

[0009] Further, the silane coupling agent is one or more of KH550, KH560, KH570, and the dosage of the silane coupling agent is 10-15% of the mass of bisphenol A epoxy resin.

[0010] Further, the curing agent is one or more of methyltetrahydrophthalic anhydride, polyamide 300, and triethylenetetramine.

[0011] Further, the leveling agent is an organosilicon leveling agent.

[0012] Further, by weight, 2-4 parts of fungicide, 0.01-0.03 parts of leveling agent, 7-9 parts of curing agent, 60-70 parts of film-forming agent and 80-100 parts of water.

[0013] Further, the film-forming agent includes 2-3 parts of glass fiber, 5-8 parts of graphene fiber, 15-18 parts of epoxy resin and 25-35 parts of solvent by weight.

[0014] Further, the fungicide includes potassium hypochlorite, methylene bisthiocyanate and tetrakis(hydroxymethyl) phosphonium sulfate with a mass ratio of 1:0.4-0.6:1.4-1.8.

[0015] Further, a preparation method of the anticorrosive coating for coastal concrete structures includes the following steps:

[0016] (1) Mix the fungicide with 40-50% of the total amount of water to obtain Component A;

[0017] (2) Mix the leveling agent, curing agent and Component A, and add the remaining water to obtain Component B;

[0018] (3) Mix Component B with the film-forming agent, heat to 50-70 °C, and stir at 200-300 r / min for 15-20 min to obtain the finished product.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] In the present invention, the components of the fungicide are rationally proportioned, which can effectively inhibit sulfate-reducing bacteria and thiobacilli and reduce the activities of sulfate-reducing bacteria and thiobacilli, and can prevent sulfate-reducing bacteria from reducing SO4 2- to S 2- , which reduces the environmental pH value. Under acidic conditions, thiobacilli convert hydrogen sulfide into biologic sulfuric acid, and biologic sulfuric acid reacts with alkaline substances (such as calcium hydroxide and calcium aluminohydrate) in concrete to generate gypsum and ettringite, resulting in damage to coastal concrete structures. At the same time, the fungicide of the present invention can also inhibit Fusarium fungi and prevent Fusarium fungi from producing organic acids through metabolism, and the organic acids react with alkaline substances (such as calcium hydroxide and calcium aluminohydrate) in concrete, resulting in damage to the concrete structure.

[0021] In the film-forming agent of the present invention, bisphenol A epoxy resin and silane coupling agent are first mixed and ball-milled, and then glass fiber, graphene fiber and solvent are added for ball-milling, which can make the glass fiber and graphene fiber uniformly dispersed in the film-forming agent, improve the crosslinking density of the epoxy resin. When the film-forming agent is mixed with the other components of the coating, it can form an excellent physical barrier, extend the penetration path of corrosive substances in the coastal environment, and achieve the purpose of anti-corrosion. The preparation method of the anti-corrosion coating for coastal concrete structures of the present invention adopts a heating and stirring method when component B and the film-forming agent are mixed, which can improve the crosslinking density of the epoxy resin and improve the use effect of the anti-corrosion coating. Detailed Embodiments

[0022] To better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0023] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0024] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can all be obtained from commercial channels.

[0025] The length of the glass fiber is 2 - 2.2 cm, and the length of the graphene fiber is 180 - 200 nm.

[0026] Example 1

[0027] The film-forming agent consists of 2 parts of glass fiber, 5 parts of graphene fiber, 15 parts of epoxy resin and 25 parts of solvent by weight. The solvent in the film-forming agent is xylene and ethyl acetate with a volume ratio of 2:1. The epoxy resin is bisphenol A epoxy resin, and the epoxy resin silane coupling agent is KH550. The dosage of the silane coupling agent is 10% of the mass of the bisphenol A epoxy resin.

[0028] The preparation method of the film-forming agent is to mix bisphenol A epoxy resin and silane coupling agent and ball-mill for 50 min, and then add glass fiber, graphene fiber and solvent and ball-mill for 30 min.

[0029] The bactericide consists of potassium hypochlorite, methylene bisthiocyanate and tetrakis(hydroxymethyl) phosphonium sulfate with a mass ratio of 1:0.4:1.4.

[0030] The leveling agent is an organosilicon leveling agent.

[0031] The curing agent is methyltetrahydrophthalic anhydride.

[0032] Weigh 2 parts of bactericide, 0.01 part of leveling agent, 7 parts of curing agent, 60 parts of film-forming agent and 80 parts of water by weight.

[0033] (1) Mix the bactericide with 40% of the total amount of water to obtain component A;

[0034] (2) Mix the leveling agent, curing agent, and Component A, and add the remaining water to obtain Component B;

[0035] (3) Mix Component B and the film-forming agent, heat to 50 °C, and stir at 200 r / min for 15 min to obtain the finished product.

[0036] Example 2

[0037] The film-forming agent consists of 3 parts of glass fiber, 8 parts of graphene fiber, 18 parts of epoxy resin, and 35 parts of solvent by weight. The solvent in the film-forming agent is xylene and ethyl acetate with a volume ratio of 4:1.5. The epoxy resin is bisphenol A, the epoxy resin silane coupling agent is KH550, and the dosage of the silane coupling agent is 15% of the mass of bisphenol A epoxy resin.

[0038] The preparation method of the film-forming agent is to mix bisphenol A epoxy resin and the silane coupling agent and ball mill for 70 min, and then add glass fiber, graphene fiber, and solvent and ball mill for 40 min.

[0039] The fungicide consists of potassium hypochlorite, methylene bisthiocyanate, and tetrakis(hydroxymethyl) phosphonium sulfate with a mass ratio of 1:0.6:1.8.

[0040] The leveling agent is an organosilicon leveling agent.

[0041] The curing agent is methyltetrahydrophthalic anhydride.

[0042] Weigh 4 parts of fungicide, 0.03 part of leveling agent, 9 parts of curing agent, 70 parts of film-forming agent, and 100 parts of water by weight.

[0043] (1) Mix the fungicide and 50% of the total amount of water to obtain Component A;

[0044] (2) Mix the leveling agent, curing agent, and Component A, and add the remaining water to obtain Component B;

[0045] (3) Mix Component B and the film-forming agent, heat to 70 °C, and stir at 300 r / min for 20 min to obtain the finished product.

[0046] Example 3

[0047] The film-forming agent consists of 2.5 parts of glass fiber, 6.5 parts of graphene fiber, 17 parts of epoxy resin, and 230 parts of solvent by weight. The solvent in the film-forming agent is xylene and ethyl acetate with a volume ratio of 3:1.25. The epoxy resin is bisphenol A epoxy resin, the epoxy resin silane coupling agent is KH550, and the dosage of the silane coupling agent is 13% of the mass of bisphenol A epoxy resin.

[0048] The preparation method of the film-forming agent is to mix bisphenol A epoxy resin and the silane coupling agent and ball mill for 60 min, and then add glass fiber, graphene fiber, and solvent and ball mill for 35 min.

[0049] The bactericide is composed of potassium hypochlorite, methylene bisthiocyanate and tetrakis(hydroxymethyl) phosphonium sulfate with a mass ratio of 1:0.5:1.6.

[0050] The leveling agent is an organosilicon leveling agent.

[0051] The curing agent is methyltetrahydrophthalic anhydride.

[0052] By weight, 3 parts of bactericide, 0.023 parts of leveling agent, 8 parts of curing agent, 65 parts of film-forming agent and 90 parts of water are weighed.

[0053] (1) Mix the bactericide with 45% of the total amount of water to obtain Component A;

[0054] (2) Mix the leveling agent, curing agent and Component A, and add the remaining water to obtain Component B;

[0055] (3) Mix Component B and the film-forming agent, heat to 60 °C, and stir at 250 r / min for 20 min to obtain the finished product.

[0056] Example 4

[0057] The film-forming agent consists of 2.5 parts of glass fiber, 6.5 parts of graphene fiber, 17 parts of epoxy resin and 230 parts of solvent by weight. The solvent in the film-forming agent is xylene and ethyl acetate with a volume ratio of 3:1.25. The epoxy resin is bisphenol A epoxy resin, and the epoxy resin silane coupling agent is KH550. The dosage of the silane coupling agent is 13% of the mass of bisphenol A epoxy resin.

[0058] The preparation method of the film-forming agent is to mix bisphenol A epoxy resin and silane coupling agent and ball mill for 60 min, and then add glass fiber, graphene fiber and solvent and ball mill for 35 min.

[0059] The bactericide is composed of potassium hypochlorite, methylene bisthiocyanate and tetrakis(hydroxymethyl) phosphonium sulfate with a mass ratio of 1:0.5:1.6.

[0060] The leveling agent is an organosilicon leveling agent.

[0061] The curing agent is polyamide 300.

[0062] By weight, 3 parts of bactericide, 0.023 parts of leveling agent, 8 parts of curing agent, 65 parts of film-forming agent and 90 parts of water are weighed.

[0063] (1) Mix the bactericide with 45% of the total amount of water to obtain Component A;

[0064] (2) Mix the leveling agent, curing agent and Component A, and add the remaining water to obtain Component B;

[0065] (3) Mix component B with the film-forming agent, heat to 60 °C, stir at 250 r / min for 20 min to obtain the finished product.

[0066] Example 5

[0067] The film-forming agent consists of 2.5 parts of glass fiber, 6.5 parts of graphene fiber, 17 parts of epoxy resin and 230 parts of solvent by weight. The solvent in the film-forming agent is xylene and ethyl acetate with a volume ratio of 3:1.25. The epoxy resin is bisphenol A epoxy resin, the epoxy resin silane coupling agent is KH550, and the dosage of the silane coupling agent is 13% of the mass of bisphenol A epoxy resin.

[0068] The preparation method of the film-forming agent is to mix bisphenol A epoxy resin and silane coupling agent and ball-mill for 60 min, then add glass fiber, graphene fiber and solvent and ball-mill for 35 min.

[0069] The fungicide consists of potassium hypochlorite, methylene bisthiocyanate and tetrakis(hydroxymethyl) phosphonium sulfate with a mass ratio of 1:0.5:1.6.

[0070] The leveling agent is an organosilicon leveling agent.

[0071] The curing agent is methyltetrahydrophthalic anhydride, polyamide 300, and triethylenetetramine with a mass ratio of 1:1:1.

[0072] Weigh 3 parts of fungicide, 0.023 parts of leveling agent, 8 parts of curing agent, 65 parts of film-forming agent and 90 parts of water by weight.

[0073] (1) Mix the fungicide with 45% of the total amount of water to obtain component A;

[0074] (2) Mix the leveling agent, curing agent and component A, and add the remaining water to obtain component B;

[0075] (3) Mix component B with the film-forming agent, heat to 60 °C, stir at 250 r / min for 20 min to obtain the finished product.

[0076] Test Example 1 Chloride ion penetration test

[0077] Detect the chloride ion permeability of the anticorrosive coatings prepared in Examples 1-5 with reference to JT / J275-2000.

[0078]

[0079] The test results show that the anticorrosive coatings prepared by the present invention can resist the erosion of chloride ions in seawater.

[0080] Test Example 2 Bacteriostatic test

[0081] Biological sulfuric acid produced by the reaction of sulfate-reducing bacteria and thiobacilli with sulfate ions and their metabolites is the main cause of microbial corrosion of concrete.

[0082] Apply the coatings of Examples 1-5 on filter paper disks with a diameter of 4 mm respectively, dry them, and set aside. Evenly smear and inoculate sulfate-reducing bacteria (SRB) and thiobacilli on the nutrient agar culture dish plates, place the coated filter paper disks on the culture dish plates, and measure the results after culturing for 24 h in a constant temperature incubator at 37°C. The negative control is distilled water, and each group is repeated 3 times.

[0083]

[0084] The experimental results show that the anti-corrosion coating of the present invention can effectively inhibit sulfate-reducing bacteria and thiobacilli, and improve the anti-corrosion effect of the coating.

[0085] Comparative Example 1

[0086] On the basis of Example 3, adjust the components of the bactericide. For details, refer to Experimental Groups 1-3:

[0087] Experimental Group 1: The bactericide is composed of potassium hypochlorite, methylene bisthiocyanate, and tetrakis(hydroxymethyl) phosphonium sulfate with a mass ratio of 1:1:1.

[0088] Experimental Group 2: The bactericide is composed of sodium bromide, glutaraldehyde, and tetrakis(hydroxymethyl) phosphonium sulfate with a mass ratio of 1:1:1.

[0089] Experimental Group 3: The bactericide is composed of zinc chloride and potassium hypochlorite with a mass ratio of 1:1.

[0090] Refer to the methods of the chloride ion penetration resistance test and the antibacterial test in Test Examples 1-2 for performance determination.

[0091]

[0092]

[0093] The test results show that the reasonable proportioning of the components of the bactericide of the present invention can effectively inhibit sulfate-reducing bacteria and thiobacilli and reduce the activities of sulfate-reducing bacteria and thiobacilli. The anti-corrosion coating of the present invention can prevent sulfate-reducing bacteria from reducing SO4 2- to S 2- , which reduces the environmental pH value. Under acidic conditions, thiobacilli convert hydrogen sulfide into biological sulfuric acid, and the biological sulfuric acid reacts with alkaline substances in concrete (such as calcium hydroxide and calcium sulfoaluminate), generating gypsum and ettringite, resulting in damage to the coastal concrete structure.

[0094] Comparative Example 2

[0095] Based on Example 3, the components of the film-forming agent were adjusted. For details, refer to Experimental Groups 4-5:

[0096] Experimental Group 4: The film-forming agent consisted of 17 parts by weight of epoxy resin and 230 parts of solvent. The solvent in the film-forming agent was xylene and ethyl acetate with a volume ratio of 3:1.25. The epoxy resin was bisphenol A epoxy resin, the epoxy resin silane coupling agent was KH550, and the dosage of the silane coupling agent was 13% of the mass of bisphenol A epoxy resin.

[0097] Experimental Group 5: The film-forming agent consisted of 2.5 parts by weight of glass fiber, 2.5 parts by weight of polyvinyl alcohol fiber, 17 parts by weight of epoxy resin and 230 parts of solvent. The solvent in the film-forming agent was xylene and ethyl acetate with a volume ratio of 3:1.25. The epoxy resin was bisphenol A epoxy resin, the epoxy resin silane coupling agent was KH550, and the dosage of the silane coupling agent was 13% of the mass of bisphenol A epoxy resin.

[0098] The performance was measured by referring to the anti-chloride ion penetration test and antibacterial test methods of Test Examples 1-2.

[0099] Name Experimental Group 4 Experimental Group 5 <![CDATA[12 - month chloride ion permeability (μg / cm 2 d)]]> 0.039 0.017 Inhibitory Zone of Sulfate-Reducing Bacteria (mm) 12.3 10.1 Inhibitory Zone of Thiobacillus (mm) 15.7 15.9

[0100] The test results show that the components of the film-forming agent of the present invention can improve the anti-corrosion performance of the coating. Adding glass fiber and graphene fiber to the film-forming agent of the present invention can improve the anti-corrosion performance of the coating. In the film-forming agent of the present invention, bisphenol A epoxy resin and silane coupling agent are first mixed and ball-milled, and then glass fiber, graphene fiber and solvent are added for ball-milling, which can make the glass fiber and graphene fiber uniformly dispersed in the film-forming agent, improve the crosslinking density of the epoxy resin. When the film-forming agent is mixed with the other components of the coating, it can form an excellent physical barrier, extend the penetration path of corrosive substances in the coastal environment, reduce water sensitivity, and achieve the purpose of anti-corrosion.

[0101] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An anti-corrosion coating for coastal concrete structures, characterized in that: The raw materials, by weight parts, include 2 - 4 parts of bactericide, 0.01 - 0.03 parts of leveling agent, 7 - 9 parts of curing agent, 60 - 70 parts of film-forming agent and 80 - 100 parts of water; the bactericide is potassium hypochlorite, methylene bisthiocyanate and tetrakis(hydroxymethyl) phosphonium sulfate with a mass ratio of 1:0.4 - 0.6:1.4 - 1.8, and the film-forming agent includes 2 - 3 parts of glass fiber, 5 - 8 parts of graphene fiber, 15 - 18 parts of epoxy resin, 25 - 35 parts of solvent and silane coupling agent by weight parts; The solvent in the film-forming agent is xylene and ethyl acetate with a volume ratio of 2 - 4:1 - 1.5, and the epoxy resin is bisphenol A epoxy resin; The preparation method of the film-forming agent is to mix bisphenol A epoxy resin and silane coupling agent and ball-mill for 50 - 70 min, then add glass fiber, graphene fiber and solvent and ball-mill for 30 - 40 min; The curing agent is one or more of methyltetrahydrophthalic anhydride, polyamide 300, triethylenetetramine; The leveling agent is an organosilicon leveling agent; A preparation method of an anti-corrosion coating for coastal concrete structures includes the following steps: (1) Mix the bactericide with 40 - 50% of the total amount of water to obtain component A; (2) Mix the leveling agent, curing agent and component A, and add the remaining water to obtain component B; Mix component B and the film-forming agent, heat to 50 - 70 °C, and stir at 200 - 300 r / min for 15 - 20 min to obtain the finished product.

2. The anti-corrosion coating for coastal concrete structures according to claim 1, characterized in that: The silane coupling agent is one or more of KH550, KH560, KH570, and the dosage of the silane coupling agent is 10 - 15% of the mass of bisphenol A epoxy resin.

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