Corrosion-resistant coating for pipeline and preparation method of corrosion-resistant coating

Abstract

The invention discloses a corrosion-resistant coating for a pipeline and a preparation method of the corrosion-resistant coating, and belongs to the technical field of coatings. The preparation method comprises the following steps: weighing 100-110 parts by weight of epoxy resin, 1-3 parts by weight of a dispersing agent, 5-10 parts by weight of a thickening thixotropic agent and 1-3 parts by weight of a defoaming agent, dispersing for 0.5-1 hour, adding 10-15 parts by weight of a diluent, stirring, and filtering by a 60-mesh screen to obtain a component A; weighing 90-100 parts of a curing agent, 50-60 parts of an anticorrosive filler and 5-10 parts of an accelerant, dispersing for 0.5 h, and filtering with a 60-mesh screen to obtain a component B; and mixing the component A and the component B according to the mass ratio of 6: (2-3), and dispersing to obtain the pipeline coating. A chemical effect exists between the anti-corrosion filler and the epoxy resin, so that the anti-corrosion filler can be highly dispersed and stably exist in the coating, powder and an organic medium in the anti-corrosion filler can give full play to a synergistic effect, and the pipeline coating is endowed with excellent and stable corrosion resistance and the like.

Description

Technical Field

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

[0002] Epoxy coatings can be divided into solvent-based epoxy coatings, high-solids epoxy coatings, and solvent-free epoxy coatings. Solvent-free epoxy coatings, as liquid coatings that do not contain volatile solvents, have low volatile matter content after film formation, low VOC (volatile organic compound) emissions, excellent corrosion resistance, are non-toxic, and offer high coating efficiency, meeting the requirements of modern coating development.

[0003] Pipelines are generally buried underground or work in dark and humid places. The dark and humid soil has high salt content, high water content, poor air permeability, and low pH value. At the same time, there are microorganisms and bacteria in the soil, which will accelerate corrosion and thus reduce the service life of the pipeline, causing huge manpower and financial losses. Therefore, the pipeline must be strictly treated with anti-corrosion to extend the service life of the pipeline. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a corrosion-resistant coating for pipelines and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a corrosion-resistant coating for a pipeline comprises the following steps:

[0007] (1) Weigh 100-110 parts of epoxy resin, 1-3 parts of dispersant, 5-10 parts of thickening thixotropic agent, and 1-3 parts of defoaming agent by weight, put them into a high-speed disperser and disperse them for 0.5-1h, then add 10-15 parts of diluent, stir thoroughly, and filter through a 60-mesh sieve to obtain component A;

[0008] (2) Weigh 90-100 parts of curing agent, 50-60 parts of anticorrosive filler and 5-10 parts of accelerator by weight, put them into a disperser and disperse them for 0.5 hours, and filter them through a 60-mesh sieve to obtain component B;

[0009] (3) Component A and component B are mixed in a mass ratio of 6:(2-3) and dispersed evenly to obtain a corrosion-resistant coating for pipelines.

[0010] Furthermore, the epoxy resin is a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 2:1.

[0011] Furthermore, the dispersant is one or more of BYK-2013 dispersant, BYK-9076 dispersant, and BYK-110 dispersant.

[0012] Furthermore, the thickening thixotropic agent is organic bentonite.

[0013] Furthermore, the defoaming agent is one or more of BYK-054 defoaming agent, BYK-A530 defoaming agent, and BYK-057 defoaming agent.

[0014] Furthermore, the diluent is one or more glycidyl ether compounds.

[0015] Furthermore, the curing agent is a mixture of polyamide and alicyclic amine in a mass ratio of (1-1.5):1.

[0016] Furthermore, the anticorrosive filler is prepared by the following steps:

[0017] S1. Under nitrogen protection, 3-(perfluorooctyl)-1,2-epoxypropane, tetradecylamine, and chloroform were added to a dry three-necked flask in sequence. After thorough stirring, the temperature was raised to 65°C and the reaction was maintained for 6 hours. After the reaction, the mixture was cooled to room temperature and then distilled under reduced pressure. Purification was performed by column chromatography (a mixed solvent of chloroform and acetone was selected as the eluent, with a volume ratio of chloroform to acetone of 19:1). Intermediate 1 was obtained by distillation under reduced pressure. The amount ratio of 3-(perfluorooctyl)-1,2-epoxypropane, tetradecylamine, and chloroform was 27.8 mL:25.1 g:250 mL.

[0018] The molar ratio of 3-(perfluorooctyl)-1,2-epoxypropylene and tetradecylamine is controlled to be 1:1.1-1.2, and the epoxy group of 3-(perfluorooctyl)-1,2-epoxypropylene and the -NH2 of tetradecylamine undergo an addition reaction under heating conditions. The reaction process is as follows:

[0019]

[0020] S2. Under nitrogen protection, add intermediate 1, triethylamine and chloroform to a dry three-necked flask, stir and dissolve, then slowly add 5-chloro-2-methyl-4-isothiazoline-3-one. After the addition is complete, heat to 80°C and stir to react for 3 hours. After the reaction is completed, cool to room temperature, then distill under reduced pressure, purify by column chromatography (a mixed solvent of benzene and acetone is selected as the eluent, and the volume ratio of benzene and acetone is 9:1), and distill under reduced pressure to obtain intermediate 2; the amount ratio of intermediate 1, 5-chloro-2-methyl-4-isothiazoline-3-one, triethylamine and chloroform is 34.5 g:6.6 mL:8.3 mL:250 mL;

[0021] Triethylamine is used as an acid-binding agent, and the molar ratio of intermediate 1 to 5-chloro-2-methyl-4-isothiazolin-3-one is controlled to be 1:1.05-1.1. Then, the -NH- of intermediate 1 and the -Cl of 5-chloro-2-methyl-4-isothiazolin-3-one undergo a nucleophilic substitution reaction. The reaction process is as follows:

[0022]

[0023] S3. Blow nitrogen through a dry three-necked flask for 30 minutes to expel air and moisture from the flask, then add intermediate 2, 3-aminopropyltriethoxysilane, tetraisopropyl titanate, and DMF (N,N-dimethylformamide) in sequence. After the addition is complete, heat to 90°C and keep warm for 24 hours. After the reaction is complete, cool to room temperature and distill under reduced pressure. Wash with anhydrous ethanol three times, dry at 80°C for 6 hours, and purify by column chromatography (using a mixed solvent of chloroform and ether as the eluent, with a volume ratio of chloroform to ether of 9:1). Finally, distill under reduced pressure to obtain intermediate 3. The usage ratio of intermediate 2, 3-aminopropyltriethoxysilane, tetraisopropyl titanate, and DMF is 28.1 g:9.7 mL:0.3 g:250 mL.

[0024] The molar ratio of intermediate 2 and 3-aminopropyltriethoxysilane is controlled to be 1:1.1-1.2. Under the catalytic action of tetraisopropyl titanate, the hydroxyl group of intermediate 2 and the siloxy group of 3-aminopropyltriethoxysilane undergo the following chemical reaction. The reaction process is shown below:

[0025]

[0026] S4. Disperse the dried powder in deionized water, add concentrated hydrochloric acid dropwise while stirring to adjust the pH to 5, and transfer the mixture to a three-necked flask after stirring for 0.5 h. Disperse the intermediate 3 in DMF, stir for 0.5 h, and transfer the mixture to the above three-necked flask. After the transfer is completed, heat the mixture to 65°C and react for 1 h. After the reaction is completed, cool the mixture to room temperature, filter the mixture, and wash it with anhydrous ethanol for 3-5 times. After washing, vacuum dry the product at 80°C for 12 h to obtain an anti-corrosion filler. The mass ratio of powder to intermediate 3 is 8:1.

[0027] Furthermore, the powder is a mixture of glass flakes, mica powder, zinc phosphate and talc powder in a mass ratio of 2:2:1:3.

[0028] Glass flakes have good corrosion resistance, wear resistance and permeability resistance. They can resist the erosion of various chemical media and extend the service life of the coating; mica powder is a natural mineral material with excellent high temperature resistance, corrosion resistance and insulation properties. It can enhance the physical properties and chemical stability of the coating and prevent the coating from failing in high temperature and corrosive environments; zinc phosphate can form a stable phosphate protective film with the metal surface to prevent the metal from being corroded. Zinc phosphate is often used for the pretreatment of metal surfaces to improve its anti-corrosion properties. It is suitable for anti-corrosion protection of various industrial equipment and pipelines.

[0029] The microparticles of talcum powder can fill the gaps in the paint, reduce light transmission, and enhance the covering effect. Its flaky structure forms a mechanical bite with the surface of the coated object to improve adhesion; the stable crystal structure of talcum powder can increase the hardness and wear resistance of the coating; the chemical inertness of talcum powder can block acid and alkali corrosion; the flaky structure of talcum powder can reflect ultraviolet rays, reduce the aging of outdoor paint, and enhance the anti-corrosion effect by extending the diffusion path of corrosive substances.

[0030] The silanol groups generated by the hydrolysis of intermediate 3 will react chemically with the hydroxyl groups on the surface of the powder to form stable chemical bonds. The formation of new chemical bonds reduces the surface energy of the powder, making the powder stable. At the same time, the organic medium on the surface of the powder particles increases the spatial resistance between the powder particles to agglomeration, thereby improving the dispersion of the powder and enabling it to fully exert its function, giving the pipeline coating excellent and stable corrosion resistance and wear resistance.

[0031] The surface of the anti-corrosion filler is rich in fluorine. Fluorine has a high electronegativity and a large bond energy of the carbon-fluorine bond. As a result, the surface tension of the fluorine-containing anti-corrosion filler is low. This low surface tension makes it difficult for liquids to wet the surface of the fluorine-containing anti-corrosion filler. As a result, the pipeline coating of the present invention has a good hydrophobic effect and is not easily corroded by water, steam, etc.

[0032] The anti-corrosion filler contains an isothiazolinone structure on its surface, which can effectively kill algae, bacteria and fungi, is non-toxic and non-polluting, has a wide pH range of use, and is easily biodegraded into non-toxic and non-polluting substances. Therefore, the anti-corrosion filler containing this structure has an antibacterial effect, and the pipeline coating of the present invention is not easily corroded by microorganisms, bacteria, etc. in the soil.

[0033] The anti-corrosion filler also contains amino groups at the end, which can chemically react with the epoxy groups in the epoxy resin in component A. As a result, the anti-corrosion filler can be highly dispersed and stably present in the coating, and is not easily migrated or removed. As a result, the powder and organic medium in the anti-corrosion filler of the present invention can fully exert a synergistic effect, giving the pipeline coating of the present invention excellent and stable corrosion resistance, hydrophobicity, and antibacterial properties, thereby greatly extending the service life of the pipeline coating.

[0034] Furthermore, the accelerator is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, RA-6 accelerator, stannous octoate, and tetramethylammonium chloride.

[0035] The present invention also discloses a corrosion-resistant coating for pipelines. The corrosion-resistant coating is prepared according to the above-mentioned method for preparing the corrosion-resistant coating for pipelines.

[0036] The present invention has the beneficial effects of: a chemical reaction between the anti-corrosion filler of the present invention and the epoxy resin allows the anti-corrosion filler of the present invention to be highly dispersed and stably present in the coating. Consequently, the powder (glass flakes, mica powder, zinc phosphate, talc) and the organic medium (fluorine element, isothiazolinone structure) in the anti-corrosion filler can fully exert a synergistic effect, imparting the pipeline coating of the present invention with excellent and stable corrosion resistance, hydrophobicity, and antibacterial properties, thereby greatly extending the service life of the pipeline coating. DETAILED DESCRIPTION

[0037] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] Example 1: Preparation of anticorrosive filler, the specific steps are as follows:

[0039] S1. Under nitrogen protection, 27.8 mL of 3-(perfluoro-n-octyl)-1,2-epoxypropane, 25.1 g of tetradecylamine, and 250 mL of chloroform were added to a 500 mL dry three-necked flask in sequence. After thorough stirring, the temperature was raised to 65°C and the reaction was maintained at this temperature for 6 h. After the reaction was completed, the product was first cooled to room temperature and then distilled under reduced pressure. The product was purified by column chromatography (a mixed solvent of chloroform and acetone was selected as the eluent, with a volume ratio of chloroform to acetone of 19:1), and distilled under reduced pressure to obtain intermediate 1.

[0040] S2. Under nitrogen protection, 34.5 g of intermediate 1, 8.3 mL of triethylamine, and 250 mL of chloroform were added to a 500 mL dry three-necked flask. After stirring to dissolve, 6.6 mL of 5-chloro-2-methyl-4-isothiazoline-3-one was slowly added. After the addition was completed, the temperature was raised to 80°C and stirred for reaction for 3 h. After the reaction was completed, the mixture was cooled to room temperature and then distilled under reduced pressure. Purification was performed by column chromatography (a mixed solvent of benzene and acetone was selected as the eluent, with a volume ratio of benzene and acetone of 9:1), and distilled under reduced pressure to obtain intermediate 2.

[0041] S3. Nitrogen was blown into a 500 mL dry three-necked flask for 30 min to expel air and moisture from the flask. Subsequently, 28.1 g of intermediate 2, 9.7 mL of 3-aminopropyltriethoxysilane, 0.3 g of tetraisopropyl titanate, and 250 mL of DMF were added in sequence. After the addition was complete, the temperature was raised to 90°C and the reaction was maintained for 24 h. After the reaction was completed, the mixture was cooled to room temperature and distilled under reduced pressure. The mixture was washed with anhydrous ethanol three times and dried at 80°C for 6 h. The mixture was purified by column chromatography (a mixed solvent of chloroform and diethyl ether was used as the eluent, with a volume ratio of chloroform to diethyl ether of 9:1). Finally, distillation was performed under reduced pressure to obtain intermediate 3.

[0042] S4. Take 10g of dry glass flakes, 10g of mica powder, 5g of zinc phosphate, and 15g of talc powder and disperse them in 250mL of deionized water. Add concentrated hydrochloric acid dropwise while stirring to adjust the pH to 5. After stirring for 0.5h, transfer them to a 500mL three-necked flask; disperse 5g of intermediate 3 in 30mL of DMF, stir for 0.5h, and transfer them to the above three-necked flask. After the transfer is completed, heat to 65℃ and react for 1h. After the reaction is completed, cool to room temperature, filter the mixture, wash with anhydrous ethanol 3-5 times, and after washing, vacuum dry the product at 80℃ for 12h to obtain an anti-corrosion filler.

[0043] Example 2: Preparation of coating for pipelines. The specific steps are as follows:

[0044] (1) Weigh 66.7 parts of bisphenol A epoxy resin E44, 33.3 parts of bisphenol F glycidyl ether NPEF-170 produced by Shenzhen Jiadida Chemical Co., Ltd., 1 part of BYK-2013 dispersant, 5 parts of organic bentonite, and 1 part of BYK-054 defoamer in parts by weight, put them into a high-speed disperser and disperse them for 0.5 h. Then, add 10 parts of cresyl glycidyl ether, stir thoroughly, and filter through a 60-mesh sieve to obtain component A.

[0045] (2) Weigh 45 parts by weight of Ancamide 2050 from American Gas Chemicals, 45 parts by weight of Ancamide 1618 from American Gas Chemicals, 50 parts by weight of the anticorrosive filler prepared in Example 1, and 5 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol, place them in a disperser and disperse them for 0.5 h, then filter through a 60-mesh sieve to obtain component B;

[0046] (3) Mix component A and component B in a mass ratio of 3:1 and disperse them evenly to obtain the coating for pipelines.

[0047] Example 3: Preparation of coating for pipelines. The specific steps are as follows:

[0048] (1) Weigh 72 parts of bisphenol A epoxy resin E44, 36 parts of bisphenol F glycidyl ether NPEF-170 produced by Shenzhen Jiadida Chemical Co., Ltd., 2 parts of BYK-9076 dispersant, 8 parts of organic bentonite, and 2 parts of 2BYK-A530 defoamer 2 in parts by weight, put them into a high-speed disperser and disperse them for 0.8 h, then add 13 parts of phenyl glycidyl ether, stir them thoroughly, and filter them through a 60-mesh sieve to obtain component A;

[0049] (2) Weigh 56 parts of Ancamide 2050 (Gas Chemicals, Inc.), 40 parts of Ancamide 1618 (Gas Chemicals, Inc.), 55 parts of the anticorrosive filler prepared in Example 1, and 8 parts of RA-6 accelerator, and disperse them in a disperser for 0.5 h. Filter through a 60-mesh sieve to obtain component B.

[0050] (3) Component A and component B are mixed in a mass ratio of 2.4:1 and dispersed evenly to obtain a coating for pipelines.

[0051] Example 4: Preparation of coating for pipelines. The specific steps are as follows:

[0052] (1) Weigh 73.3 parts of bisphenol A epoxy resin E44, 36.7 parts of bisphenol F glycidyl ether (Shenzhen Jiadida Chemical Co., Ltd.), 1 part of BYK-2013 dispersant, 2 parts of BYK-110 dispersant, 10 parts of organic bentonite, 2 parts of BYK-054 defoamer, and 1 part of BYK-057 defoamer in parts by weight, put them into a high-speed disperser and disperse them for 1 hour, then add 7 parts of phenyl glycidyl ether and 8 parts of butyl glycidyl ether, stir them thoroughly, and filter them through a 60-mesh sieve to obtain component A;

[0053] (2) Weigh 60 parts by weight of Ancamide 2050 (available from American Gas Chemicals), 40 parts of Ancamide 1618 (available from American Gas Chemicals), 60 parts of the anti-corrosion filler prepared in Example 1, and 10 parts of tetramethylammonium chloride, place the mixture in a disperser and disperse for 0.5 h, then filter through a 60-mesh sieve to obtain component B;

[0054] (3) Mix component A and component B in a mass ratio of 2:1 and disperse them evenly to obtain the coating for pipelines.

[0055] Comparative Example 1: Preparation of coating for pipelines, the specific steps are as follows:

[0056] The remaining steps remain unchanged, and the anti-corrosion filler in Example 2 is replaced by 12.5 parts of glass flakes, 12.5 parts of mica powder, 6.25 parts of zinc phosphate, and 18.75 parts of talc to prepare a coating for pipelines.

[0057] Performance Testing

[0058] At 25°C and a relative humidity of 55%, a tinplate sheet was used as a substrate, and the pipe coatings prepared in Examples 2-4 and Comparative Example 1 were heated at a temperature of 0.15 kg / m 2 The dosage is roller coating, and after 24 hours, it is applied at 0.15kg / m 2 Roll on once and test the performance after 7 days of curing. The test results are shown in the following table:

[0059]

[0060] From the above test results, it can be seen that the pipeline coatings prepared in Examples 2-4 of the present invention have excellent corrosion resistance and hydrophobic effect.

[0061] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0062] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a corrosion-resistant coating for a pipeline, characterized in that: The following steps are involved: (1) Weigh 100-110 parts of epoxy resin, 1-3 parts of dispersant, 5-10 parts of thickening thixotropic agent, and 1-3 parts of defoaming agent by weight, put them into a high-speed disperser and disperse them for 0.5-1h, then add 10-15 parts of diluent, stir thoroughly, and filter through a 60-mesh sieve to obtain component A; (2) Weigh 90-100 parts of curing agent, 50-60 parts of anticorrosive filler and 5-10 parts of accelerator by weight, put them into a disperser and disperse them for 0.5 hours, and filter them through a 60-mesh sieve to obtain component B; (3) Component A and component B are mixed in a mass ratio of 6:(2-3) and dispersed evenly to obtain a corrosion-resistant coating for pipelines; Wherein, the anticorrosive filler is prepared by the following steps: S1. Add 3-(perfluorooctyl)-1,2-propylene oxide, tetradecylamine, and chloroform to a flask under nitrogen protection, stir, heat to 65°C, react for 6 hours, cool, evaporate under reduced pressure, purify by column chromatography, and evaporate under reduced pressure to obtain intermediate 1; S2. Under nitrogen protection, intermediate 1, triethylamine and chloroform were added to a flask, stirred, 5-chloro-2-methyl-4-isothiazolin-3-one was added, the temperature was raised to 80°C, the reaction was continued for 3 hours, cooled, and distilled under reduced pressure. Purification was performed by column chromatography and distilled under reduced pressure to obtain intermediate 2. S3. After nitrogen was purged into the flask, intermediate 2, 3-aminopropyltriethoxysilane, tetraisopropyl titanate, and DMF were added, and the mixture was heated to 90°C and reacted for 24 hours. The mixture was cooled, evaporated under reduced pressure, washed with anhydrous ethanol, dried, purified by column chromatography, and evaporated under reduced pressure to obtain intermediate 3. S4. Disperse the powder in deionized water, add concentrated hydrochloric acid to adjust the pH to 5, stir and transfer to a flask; Intermediate 3 was dispersed in DMF, stirred and transferred to the above flask, heated to 65°C for reaction for 1 hour, cooled, filtered, washed with anhydrous ethanol, and dried to obtain an anticorrosive filler; The powder in step S4 is a mixture of glass flakes, mica powder, zinc phosphate, and talc powder in a mass ratio of 2:2:1:

3.

2. The method for preparing a corrosion-resistant coating for pipelines according to claim 1, characterized in that: The amount ratio of 3-(perfluorooctyl)-1,2-propylene oxide, tetradecylamine and chloroform in step S1 is 27.8 mL:25.1 g:250 mL; the amount ratio of intermediate 1, 5-chloro-2-methyl-4-isothiazoline-3-one, triethylamine and chloroform in step S2 is 34.5 g:6.6 mL:8.3 mL:250 mL; the amount ratio of intermediate 2, 3-aminopropyltriethoxysilane, tetraisopropyl titanate and DMF in step S3 is 28.1 g:9.7 mL:0.3 g:250 mL; the mass ratio of the powder in step S4 to intermediate 3 is 8:

1.

3. The method for preparing a corrosion-resistant coating for pipelines according to claim 1, characterized in that: The epoxy resin is a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 2:

1.

4. The method for preparing a corrosion-resistant coating for pipelines according to claim 1, characterized in that: The dispersant is one or more of BYK-2013 dispersant, BYK-9076 dispersant, and BYK-110 dispersant.

5. The method for preparing a corrosion-resistant coating for pipelines according to claim 1, characterized in that: The thickening thixotropic agent is organic bentonite.

6. The method for preparing a corrosion-resistant coating for pipelines according to claim 1, characterized in that: The defoaming agent is one or more of BYK-054 defoaming agent, BYK-A530 defoaming agent, and BYK-057 defoaming agent.

7. The method for preparing a corrosion-resistant coating for pipelines according to claim 1, characterized in that: The diluent is one or more glycidyl ether compounds.

8. The method for preparing a corrosion-resistant coating for pipelines according to claim 1, characterized in that: The curing agent is a mixture of polyamide and alicyclic amine in a mass ratio of (1-1.5):

1.

9. The method for preparing a corrosion-resistant coating for pipelines according to claim 1, characterized in that: The accelerator is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, RA-6 accelerator, stannous octoate, and tetramethylammonium chloride.

10. A corrosion-resistant coating for pipelines, characterized in that: The corrosion-resistant coating for pipelines is prepared according to the preparation method of any one of claims 1 to 9.

Images