Weather-resistant and corrosion-resistant polyurea coating, and preparation method and application thereof

Abstract

The application discloses weather-resistant and corrosion-resistant polyurea paint as well as a preparation method and application thereof. The weather-resistant and corrosion-resistant polyurea paint comprises the following components in parts by weight: A component: fluorosilicon modified amino resin 20-40 parts; amino-terminated polyether 30-50 parts; amino chain extender 15-30 parts; dispersant 0.2-1 part; defoaming agent 0.2-1 part; B component: isocyanate curing agent 100 parts. The polyurea paint has low solvent content, is green and environment-friendly, and has the advantages of excellent weather resistance, excellent corrosion resistance, excellent mechanical properties, excellent medium resistance and the like. When used for steel structure corrosion prevention, the polyurea paint can provide long-term protection for the steel structure, and is suitable for large-scale industrial production and application.

Description

Technical Field

[0001] This invention relates to the field of metal corrosion protection technology, specifically to a weather-resistant and corrosion-resistant polyurea coating, its preparation method, and its application. Background Technology

[0002] Steel structures, composed of steel materials, are one of the main types of building structures, and their applications are becoming increasingly widespread. Steel structures are exposed to the external environment for extended periods, making them susceptible to corrosion due to temperature and humidity fluctuations. This not only severely impacts their service life and safety but also leads to resource waste and environmental pollution. Currently, coating steel structures with weather-resistant and corrosion-resistant coatings is the primary method of corrosion protection. Polyurea coatings offer advantages such as rapid curing, applicability to any surface without dripping or sagging, low-temperature application, insensitivity to moisture, and environmental friendliness, making them a relatively common anti-corrosion coating for steel structures. However, the weather resistance, corrosion resistance, mechanical properties, and media resistance of existing polyurea coatings are no longer sufficient to fully meet the growing demands of practical applications and cannot adequately provide long-term protection for steel structures.

[0003] Therefore, it is of great significance to develop a polyurea coating with excellent weather resistance, corrosion resistance, mechanical properties and media resistance after film formation. Summary of the Invention

[0004] The purpose of this invention is to provide a weather-resistant and corrosion-resistant polyurea coating, its preparation method, and its application.

[0005] The technical solution adopted in this invention is:

[0006] A weather-resistant and corrosion-resistant polyurea coating, comprising the following components in parts by weight:

[0007] Component A:

[0008] Fluorosilicone modified amino resin: 20 parts to 40 parts;

[0009] Amino-terminated resin: 30 to 50 parts;

[0010] Amino chain extender: 15 to 30 parts;

[0011] Dispersant: 0.2 parts to 1 part;

[0012] Defoamer: 0.2 parts to 1 part;

[0013] Component B:

[0014] Isocyanate curing agent: 100 parts.

[0015] Preferably, the fluorosilicone-modified amino resin is prepared by a method comprising the following steps:

[0016] a) Disperse silane-containing amino monomers, diene silanes and platinum catalysts in an organic solvent, and then react them under a protective atmosphere to obtain silane-hydrogen bond-terminated silicon-modified amino resins.

[0017] b) The silicon-hydrogen bond-terminated modified amino resin, fluorinated olefin and platinum catalyst are dispersed in an organic solvent and then reacted under a protective atmosphere to obtain the fluorosilicone modified amino resin.

[0018] Preferably, the silane-containing amino monomer in step a) is at least one of tetramethyldisilazane (CAS No.: 15933-59-2), N-(diethylsilyl)-1,1-diethylsilaneamine (CAS No.: 17882-96-1), and 1-methyl-1-isopropyl-N-[methyl(1-isopropyl)silyl]silaneamine (CAS No.: 2227-38-5).

[0019] Preferably, the diene silane in step a) is at least one of tetramethyldivinyldisiloxane (CAS No.: 2627-95-4), 1,7-divinyl-octamethyltetrasiloxane (CAS No.: 13315-13-4), tetraethoxydivinyldisiloxane (CAS No.: 3682-26-6), 1,3-divinyl-1,1,3,3-tetramethoxydisiloxane (CAS No.: 18293-85-1), and divinyltetra(trimethylsiloxy)disiloxane (CAS No.: 94071-24-6).

[0020] Preferably, the platinum catalyst in step a) is platinum-diethylenetetramethyldisiloxane.

[0021] Preferably, the organic solvent in step a) is toluene.

[0022] Preferably, the protective atmosphere in step a) is a nitrogen atmosphere or an argon atmosphere.

[0023] Preferably, the reaction in step a) is carried out at a temperature of 60°C to 110°C for a reaction time of 6 h to 24 h.

[0024] Preferably, after the reaction in step a) is completed, a depressurization process to remove volatiles is also performed.

[0025] Preferably, the fluorinated olefin in step b) is at least one of allyl 2,2,3,3-tetrafluoropropyl ether (CAS No.: 681-68-5), allyl 1,1,2,2-tetrafluoroethyl ether (CAS No.: 1428-33-7), allyl 1,1,2,3,3,3-hexafluoropropyl ether (CAS No.: 59158-81-5), and allyl 1H,1H-heptafluorobutyl ether (CAS No.: 648-42-0).

[0026] Preferably, the platinum catalyst in step b) is platinum-diethylenetetramethyldisiloxane.

[0027] Preferably, the organic solvent in step b) is toluene.

[0028] Preferably, the protective atmosphere in step b) is a nitrogen atmosphere or an argon atmosphere.

[0029] Preferably, the reaction in step b) is carried out at a temperature of 60°C to 110°C for a reaction time of 6 h to 24 h.

[0030] Preferably, after the reaction in step b) is completed, a depressurization process to remove volatiles is also performed.

[0031] Preferably, the number-average molecular weight of the terminal amino resin is 1000 g / mol to 5000 g / mol.

[0032] Preferably, the amino-terminated resin is at least one of difunctional amino-terminated polyether, difunctional amino-terminated polytetrahydrofuran, and difunctional amino-terminated polypropylene oxide.

[0033] Preferably, the amino chain extender is at least one selected from polyetheramine, diethyltoluene diamine (DETDA), 4,4′-diaminodicyclohexylmethane (MDA), and trimethylhexanediamine.

[0034] Preferably, the dispersant is at least one of polycarboxylate and polyacrylate.

[0035] Preferably, the defoamer is at least one of silicone defoamers and polyether defoamers.

[0036] Preferably, the weight percentage of -NCO groups in the isocyanate curing agent is 12% to 20%.

[0037] Preferably, the isocyanate curing agent is prepared by a method comprising the following steps: dispersing an aliphatic isocyanate in an organic solvent, and then slowly adding a terminal amino resin to react, thereby obtaining the isocyanate curing agent.

[0038] Preferably, the aliphatic isocyanate is at least one selected from hexamethylene diisocyanate (HDI) trimer, isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), and methylcyclohexyl diisocyanate (HTDI).

[0039] Preferably, the organic solvent is at least one of propyl carbonate, diisopentylmethyl phosphate, and n-butyl acetate (BAC).

[0040] Preferably, the number-average molecular weight of the terminal amino resin is 1000 g / mol to 5000 g / mol.

[0041] Preferably, the amino-terminated resin is at least one of a mixture of difunctional amino-terminated polyether, difunctional amino-terminated polytetrahydrofuran, and difunctional amino-terminated polypropylene oxide.

[0042] Preferably, the amino-terminated resin is subjected to vacuum dehydration treatment before use.

[0043] Preferably, the reaction is carried out at a temperature of 20°C to 40°C for a reaction time of 2 hours to 6 hours.

[0044] A method for preparing a weather-resistant and corrosion-resistant polyurea coating as described above includes the following steps:

[0045] 1) Mix fluorosilicone modified amino resin, terminal amino resin, amino chain extender, dispersant and defoamer to form component A, and use isocyanate curing agent as component B;

[0046] 2) Mix component A and component B thoroughly to obtain a weather-resistant and corrosion-resistant polyurea coating.

[0047] Application of a weather-resistant and corrosion-resistant polyurea coating as described above in the corrosion protection of steel structures.

[0048] Preferably, the steel structure is one of a steel oil and gas pipeline or a steel petrochemical storage tank.

[0049] The beneficial effects of this invention are: the polyurea coating of this invention has low solvent content, is green and environmentally friendly, and the resulting paint film has excellent weather resistance, excellent corrosion resistance, excellent mechanical properties, and excellent resistance to media. When used for steel structure corrosion protection, it can provide long-term protection for steel structures and is suitable for large-scale industrial production and application.

[0050] Specifically:

[0051] 1) The polyurea coating of the present invention contains fluorosilicone modified amino resin, which can impart long-lasting weather resistance and anti-corrosion properties to the coating film.

[0052] 2) The polyurea coating of the present invention contains an amino-terminated resin and an amino chain extender. The amino-terminated resin and the amino chain extender react with the isocyanate curing agent to generate urea groups containing dual-coordinated hydrogen bonds and form a micro-phase separation structure, thereby giving the coating film excellent mechanical properties.

[0053] 3) The polyurea coating of the present invention contains an isocyanate curing agent made by reacting terminal amino resin and aliphatic isocyanate, which can improve the degree of hydrogen bonding of the coating film, thereby further improving the mechanical properties and media resistance of the coating film.

[0054] 4) The polyurea coating of the present invention has low solvent content, is green and environmentally friendly, and can be widely used for the protection of outdoor steel substrate surfaces (e.g., for the outer wall protection of oil and gas pipelines and petrochemical storage tanks). Detailed Implementation

[0055] The present invention will be further explained and described below with reference to specific embodiments.

[0056] Example 1:

[0057] A weather-resistant and corrosion-resistant polyurea coating, the composition of which is shown in the table below:

[0058] Table 1. Composition of a weather-resistant and corrosion-resistant polyurea coating.

[0059]

[0060] Note:

[0061] The NCO index is 1.05.

[0062] The preparation method of fluorosilicone modified amino resin is as follows:

[0063] a) Add 80 mL of tetramethyldisilazane, 60 mL of tetramethyldivinyldisilazane, 1.82 mL of Karstedt catalyst (main component: platinum-diethylenetetramethyldisilazane) and 150 g of toluene to the reactor, then evacuate for 15 min and purge with nitrogen for 5 min. Repeat the evacuation-nitrogen purging operation 3 times, then stir the reaction at 60 °C for 8 h, and then remove all volatiles under reduced pressure to obtain silicon-hydrogen bond-terminated silicon-modified amino resin.

[0064] b) Add 48g of silane-hydrogen bond-terminated silicon-modified amino resin, 31.6g of allyl 1,1,2,2-tetrafluoroethyl ether, 1.6mL of Karstedt catalyst and 50g of toluene to the reactor, then evacuate for 15min and purge with nitrogen for 5min. Repeat the evacuation-nitrogen purging operation 3 times, then stir the reaction at 80℃ for 12h, and then remove all volatiles under reduced pressure to obtain fluorosilicone-modified amino resin.

[0065] The preparation method of isocyanate curing agents is as follows:

[0066] amino-terminated resin D-2000 was placed at 80℃ for vacuum dehydration, and then 100g of amino-terminated resin was added. D-2000 was added dropwise to a reactor containing 100g of isophorone diisocyanate and 10.5g of n-butyl acetate, and the mixture was stirred at 30°C for 4 hours to obtain an isocyanate curing agent (with a weight percentage of -NCO groups of 12% to 20%).

[0067] The preparation method of the above-mentioned weather-resistant and corrosion-resistant polyurea coating is as follows:

[0068] 1) Fluorosilicone-modified amino resin, amino-terminated resin D-2000, diethyltoluenediamine, dispersant BYK-P104S and defoamer BYK-057 are mixed and then stirred for 15 minutes at room temperature and a mixer speed of 1500 r / min to prepare component A, and isocyanate curing agent is used as component B.

[0069] 2) Mix components A and B evenly to obtain a weather-resistant and corrosion-resistant polyurea coating.

[0070] Example 2:

[0071] A weather-resistant and corrosion-resistant polyurea coating, the composition of which is shown in the table below:

[0072] Table 2. Composition of a weather-resistant and corrosion-resistant polyurea coating.

[0073]

[0074] Note:

[0075] The NCO index is 1.05.

[0076] The preparation method of fluorosilicone modified amino resin is as follows:

[0077] a) Add 80 mL of tetramethyldisilazane, 60 mL of tetramethyldivinyldisilazane, 1.82 mL of Karstedt catalyst and 150 g of toluene to the reactor, then evacuate for 15 min and purge with nitrogen for 5 min. Repeat the evacuation-nitrogen purging operation 3 times, then stir the reaction at 60 °C for 8 h, and then remove all volatiles under reduced pressure to obtain silicon-hydrogen bond-terminated silicon-modified amino resin.

[0078] b) Add 48g of silane-hydrogen bond-terminated silicon-modified amino resin, 41.6g of allyl 1,1,2,3,3,3-hexafluoropropyl ether, 1.6mL of Karstedt catalyst and 50g of toluene to the reactor, then evacuate for 15min and purge with nitrogen for 5min. Repeat the evacuation-nitrogen purging operation 3 times, then stir the reaction at 100℃ for 12h, and then remove all volatiles under reduced pressure to obtain fluorosilicone-modified amino resin.

[0079] The preparation method of isocyanate curing agents is as follows:

[0080] amino-terminated resin THF-100 (Hunsmay) was placed at 80°C for vacuum dehydration, and then 90g of amino-terminated resin was added. THF-100 was added dropwise to a reactor containing 100g of isophorone diisocyanate and 10g of n-butyl acetate, and the mixture was stirred at room temperature for 4 hours to obtain an isocyanate curing agent (with a weight percentage of -NCO groups of 12% to 20%).

[0081] The preparation method of the above-mentioned weather-resistant and corrosion-resistant polyurea coating is as follows:

[0082] 1) Fluorosilicone-modified amino resin, amino-terminated resin D-2000, Amino-terminated resin T-5000, diethyltoluenediamine, dispersant BYK-P104S and defoamer BYK-057 are mixed and then stirred for 15 minutes at room temperature and a mixer speed of 1500 r / min to prepare component A, and isocyanate curing agent is used as component B.

[0083] 2) Mix components A and B evenly to obtain a weather-resistant and corrosion-resistant polyurea coating.

[0084] Example 3:

[0085] A weather-resistant and corrosion-resistant polyurea coating, the composition of which is shown in the table below:

[0086] Table 3. Composition of a weather-resistant and corrosion-resistant polyurea coating.

[0087]

[0088] Note:

[0089] The NCO index is 1.05.

[0090] The preparation method of fluorosilicone modified amino resin is as follows:

[0091] a) Add 80 mL of tetramethyldisilazane, 60 mL of tetramethyldivinyldisilazane, 1.82 mL of Karstedt catalyst and 150 g of toluene to the reactor, then evacuate for 15 min and purge with nitrogen for 5 min. Repeat the evacuation-nitrogen purging operation 3 times, then stir the reaction at 60 °C for 8 h, and then remove all volatiles under reduced pressure to obtain silicon-hydrogen bond-terminated silicon-modified amino resin.

[0092] b) Add 48g of silane-hydrogen bond-terminated silicon-modified amino resin, 34.2g of allyl 2,2,3,3-tetrafluoropropyl ether, 1.6mL of Karstedt catalyst and 50g of toluene to the reactor, then evacuate for 15min and purge with nitrogen for 5min. Repeat the evacuation-nitrogen purging operation 3 times, then stir the reaction at 80℃ for 12h, and then remove all volatiles under reduced pressure to obtain fluorosilicone-modified amino resin.

[0093] The preparation method of isocyanate curing agents is as follows:

[0094] The end-amino resin with a weight ratio of 1:1 THF-100 and amino-terminated resin The D-2000 mixture was placed at 80°C for vacuum dehydration, and then 96g of amino-terminated resin was added. THF-100 and amino-terminated resin The D-2000 mixture was added dropwise to a reactor containing 100g of isophorone diisocyanate and 10.3g of n-butyl acetate. The mixture was stirred at room temperature for 4 hours to obtain an isocyanate curing agent (with a weight percentage of -NCO groups of 12% to 20%).

[0095] The preparation method of the above-mentioned weather-resistant and corrosion-resistant polyurea coating is as follows:

[0096] 1) Fluorosilicone-modified amino resin, amino-terminated resin D-2000, Amino-terminated resin T-5000, diethyltoluenediamine, dispersant BYK-P104S and defoamer BYK-057 are mixed and then stirred for 15 minutes at room temperature and a mixer speed of 1500 r / min to prepare component A, and isocyanate curing agent is used as component B.

[0097] 2) Mix components A and B evenly to obtain a weather-resistant and corrosion-resistant polyurea coating.

[0098] Example 4:

[0099] A weather-resistant and corrosion-resistant polyurea coating, the composition of which is shown in the table below:

[0100] Table 4. Composition of a weather-resistant and corrosion-resistant polyurea coating.

[0101]

[0102] Note:

[0103] The NCO index is 1.05.

[0104] The preparation method of fluorosilicone modified amino resin is as follows:

[0105] a) Add 80 mL of tetramethyldisilazane, 99 mL of 1,7-divinyl-octamethyltetrasiloxane, 1.9 mL of Karstedt catalyst and 100 g of toluene to the reactor, then evacuate for 15 min and purge with nitrogen for 5 min. Repeat the evacuation-nitrogen purging operation 3 times, then stir the reaction at 60 °C for 10 h, and then remove all volatiles under reduced pressure to obtain silicon-hydrogen bond-terminated silicon-modified amino resin.

[0106] b) Add 48g of silane-hydrogen bond-terminated silicon-modified amino resin, 24g of allyl 1,1,2,2-tetrafluoroethyl ether, 1.8mL of Karstedt catalyst and 50g of toluene to the reactor, then evacuate for 15min and purge with nitrogen for 5min. Repeat the evacuation-nitrogen purging operation 3 times, then stir the reaction at 80℃ for 16h, and then remove all volatiles under reduced pressure to obtain fluorosilicone-modified amino resin.

[0107] The preparation method of isocyanate curing agents is as follows:

[0108] amino-terminated resin THF-100 was placed at 80℃ for vacuum dehydration, and then 70g of amino-terminated resin was added. THF-100 was added dropwise to a reactor containing 100g of isophorone diisocyanate and 9g of n-butyl acetate, and the mixture was stirred at room temperature for 4 hours to obtain an isocyanate curing agent (with a weight percentage of -NCO groups of 12% to 20%).

[0109] The preparation method of the above-mentioned weather-resistant and corrosion-resistant polyurea coating is as follows:

[0110] 1) Fluorosilicone-modified amino resin, amino-terminated resin D-2000, Amino-terminated resin T-5000, diethyltoluenediamine, dispersant BYK-P104S and defoamer BYK-057 are mixed and then stirred for 15 minutes at room temperature and a mixer speed of 1500 r / min to prepare component A, and isocyanate curing agent is used as component B.

[0111] 2) Mix components A and B evenly to obtain a weather-resistant and corrosion-resistant polyurea coating.

[0112] Example 5:

[0113] A weather-resistant and corrosion-resistant polyurea coating, the composition of which is shown in the table below:

[0114] Table 5. Composition of a weather-resistant and corrosion-resistant polyurea coating.

[0115]

[0116] Note:

[0117] The NCO index is 1.05.

[0118] The preparation method of fluorosilicone modified amino resin is as follows:

[0119] a) Add 80 mL of tetramethyldisilazane, 99 mL of 1,7-divinyl-octamethyltetrasiloxane, 1.9 mL of Karstedt catalyst and 100 g of toluene to the reactor, then evacuate for 15 min and purge with nitrogen for 5 min. Repeat the evacuation-nitrogen purging operation 3 times, then stir the reaction at 60 °C for 10 h, and then remove all volatiles under reduced pressure to obtain silicon-hydrogen bond-terminated silicon-modified amino resin.

[0120] b) Add 48g of silane-hydrogen bond-terminated silicon-modified amino resin, 36.1g of allyl 1H,1H-heptafluorobutyl ether, 1.7mL of Karstedt catalyst and 50g of toluene to the reactor, then evacuate for 15min and purge with nitrogen for 5min. Repeat the evacuation-nitrogen purging operation 3 times, then stir the reaction at 100℃ for 24h, and then remove all volatiles under reduced pressure to obtain fluorosilicone-modified amino resin.

[0121] The preparation method of isocyanate curing agents is as follows:

[0122] amino-terminated resin THF-100 was placed at 80℃ for vacuum dehydration, and then 90g of amino-terminated resin was added. THF-100 was added dropwise to a reactor containing 100g of isophorone diisocyanate and 10g of n-butyl acetate, and the mixture was stirred at room temperature for 4 hours to obtain an isocyanate curing agent (with a weight percentage of -NCO groups of 12% to 20%).

[0123] The preparation method of the above-mentioned weather-resistant and corrosion-resistant polyurea coating is as follows:

[0124] 1) Fluorosilicone-modified amino resin, amino-terminated resin D-2000, Amino-terminated resin T-5000, diethyltoluenediamine, dispersant BYK-P104S and defoamer BYK-057 are mixed and then stirred for 15 minutes at room temperature and a mixer speed of 1500 r / min to prepare component A, and isocyanate curing agent is used as component B.

[0125] 2) Mix components A and B evenly to obtain a weather-resistant and corrosion-resistant polyurea coating.

[0126] Comparative Example 1:

[0127] A polyurea coating, the composition of which is shown in the table below:

[0128] Table 6. Composition of a polyurea coating

[0129]

[0130]

[0131] Note: The NCO index is 1.05.

[0132] The preparation method of the above-mentioned polyurea coating is as follows:

[0133] 1) Terminal amino resin D-2000, Amino-terminated resin T-5000, diethyltoluenediamine, dispersant BYK-P104S, and defoamer BYK-057 were mixed and then stirred for 15 minutes at room temperature and a mixer speed of 1500 rpm to prepare component A. 2054 curing agent is used as component B;

[0134] 2) Mix components A and B evenly to obtain the polyurea coating.

[0135] Comparative Example 2:

[0136] A polyurea coating, the composition of which is shown in the table below:

[0137] Table 7 Composition of a polyurea coating

[0138]

[0139] Note: The NCO index is 1.05.

[0140] The preparation method of the above-mentioned polyurea coating is as follows:

[0141] 1) Terminal amino resin D-2000, Amino-terminated resin T-5000, diethyltoluenediamine, dispersant BYK-P104S and defoamer BYK-057 are mixed and then stirred for 15 minutes at room temperature and a mixer speed of 1500 r / min to prepare component A, and isocyanate curing agent is used as component B.

[0142] 2) Mix components A and B evenly to obtain the polyurea coating.

[0143] Comparative Example 3:

[0144] A polyurea coating, the composition of which is shown in the table below:

[0145] Table 8. Composition of a polyurea coating

[0146]

[0147]

[0148] Note: The NCO index is 1.05.

[0149] The preparation method of the above-mentioned polyurea coating is as follows:

[0150] 1) Mix fluorosilicone modified amino resin, diethyltoluene diamine, dispersant BYK-P104S and defoamer BYK-057, and then stir for 15 minutes at room temperature and a mixer speed of 1500 r / min to prepare component A, and use isocyanate curing agent as component B.

[0151] 2) Mix components A and B evenly to obtain the polyurea coating.

[0152] Performance testing:

[0153] The polyurea coatings of Examples 1-5 and Comparative Examples 1-3 were sprayed onto steel plates, cured into films, and then the performance of the coating films was tested. The test results are shown in the table below:

[0154] Table 9. Performance test results of the polyurea coatings formed in Examples 1-5

[0155]

[0156] Table 10 shows the performance test results of the coating films formed by the polyurea coatings in Comparative Examples 1–3.

[0157]

[0158]

[0159] Note:

[0160] Resistance to neutral salt spray: Tested according to "GB / T 1771-2007 Determination of resistance to neutral salt spray of paints and varnishes";

[0161] UV aging resistance: Tested according to "GB / T 1865-2009 Paints and Varnishes Artificial climate aging and artificial radiation exposure filtered xenon arc radiation";

[0162] Adhesion: Tested according to "GB / T 9286-2021 Cross-cut test for paint and varnish film";

[0163] Pencil hardness: The test was conducted according to "GB / T 6739-2022 Pencil method for determining the hardness of paint and varnish film";

[0164] Acid resistance: Tested according to Method A in "GB / T 9274-1988 Determination of resistance to liquid media of paints and varnishes";

[0165] Alkali resistance: Tested according to Method A in "GB / T 9274-1988 Determination of resistance to liquid media for paints and varnishes".

[0166] As can be seen from Tables 9 and 10:

[0167] 1) The polyurea coatings in Examples 1-5 exhibit excellent weather resistance and corrosion resistance, indicating that the present invention, by compounding fluorosilicone modified amino resin, amino-terminated polyether, and amino chain extender with isocyanate curing agent, can obtain polyurea coatings with excellent weather resistance, corrosion resistance, mechanical properties, and media resistance. These coatings can be widely used for the protection of steel substrate surfaces, extending the service life of steel structures and saving resources.

[0168] 2) The polyurea coatings in Examples 1-5 incorporate fluorosilicone-modified amino resins and employ isocyanate curing agents prepared by reacting terminal amino resins and aliphatic isocyanates. The resulting coatings exhibit superior corrosion and weather resistance compared to the polyurea coatings of Comparative Example 1 (which do not contain fluorosilicone-modified amino resins or isocyanate curing agents prepared by reacting terminal amino resins and aliphatic isocyanates) and Comparative Example 2 (which do not contain fluorosilicone-modified amino resins). This is because the bond energies of the CF and Si-O bonds are very high (426 kJ / mol and 422 kJ / mol, respectively), and only wavelengths less than 220 nm... Only photons with wavelengths less than 220 nm can break these chemical bonds, and the proportion of photons with wavelengths less than 220 nm in sunlight is very small. Therefore, sunlight has little effect on fluorosilicone-modified amino resins. Introducing fluorosilicone-modified amino resins can significantly improve the weather resistance of the paint film. At the same time, the introduction of fluorine and silicon atoms can also reduce the surface tension of the paint film, improve its hydrophobicity, and thus improve its salt spray resistance. In addition, since the bond energy and chemical resistance of urea groups are higher than those of urethane groups, the paint film formed by polyurea coatings using isocyanate curing agents made from terminal amino resins and aliphatic isocyanates has better resistance to media.

[0169] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A weather-resistant and corrosion-resistant polyurea coating, characterized in that, The components include the following parts by weight: Component A: Fluorosilicone modified amino resin: 20 parts to 40 parts; Amino-terminated resin: 30 to 50 parts; Amino chain extender: 15 to 30 parts; Dispersant: 0.2 parts to 1 part; Defoamer: 0.2 parts to 1 part; Component B: Isocyanate curing agent: 100 parts; The fluorosilicone-modified amino resin is prepared by a method including the following steps: a) Disperse silane-containing amino monomers, diene silanes and platinum catalysts in an organic solvent, and then react them under a protective atmosphere to obtain silane-hydrogen bond-terminated silicon-modified amino resins. b) Disperse the silicon-hydrogen bond-terminated silicon-modified amino resin, fluorinated olefin and platinum catalyst in an organic solvent, and then react them under a protective atmosphere to obtain fluorosilicone-modified amino resin. The silane-containing amino monomer in step a) is tetramethyldisilazane.

2. The weather-resistant and corrosion-resistant polyurea coating according to claim 1, characterized in that: The diene silane in step a) is at least one of tetramethyldivinyldisiloxane, 1,7-divinyl-octamethyltetrasiloxane, tetraethoxydivinyldisiloxane, 1,3-divinyl-1,1,3,3-tetramethoxydisiloxane, and divinyltetra(trimethylsiloxy)disiloxane; the fluorinated olefin in step b) is at least one of allyl 2,2,3,3-tetrafluoropropyl ether, allyl 1,1,2,2-tetrafluoroethyl ether, allyl 1,1,2,3,3,3-hexafluoropropyl ether, and allyl 1H,1H-heptafluorobutyl ether.

3. The weather-resistant and corrosion-resistant polyurea coating according to claim 1, characterized in that: The reaction in step a) is carried out at a temperature of 60℃ to 110℃ for a reaction time of 6h to 24h; the reaction in step b) is carried out at a temperature of 60℃ to 110℃ for a reaction time of 6h to 24h.

4. The weather-resistant and corrosion-resistant polyurea coating according to any one of claims 1 to 3, characterized in that: The number-average molecular weight of the amino-terminated resin is 1000 g / mol to 5000 g / mol; the amino-terminated resin is at least one of difunctional amino-terminated polyether, difunctional amino-terminated polytetrahydrofuran, and difunctional amino-terminated polypropylene oxide; the amino chain extender is at least one of polyetheramine, diethyltoluenediamine, 4,4′-diaminodicyclohexylmethane, and trimethylhexanediamine; the dispersant is at least one of polycarboxylate and polyacrylate; and the defoamer is at least one of silicone defoamer and polyether defoamer.

5. The weather-resistant and corrosion-resistant polyurea coating according to any one of claims 1 to 3, characterized in that: The isocyanate curing agent contains 12% to 20% by weight of -NCO groups.

6. The weather-resistant and corrosion-resistant polyurea coating according to claim 5, characterized in that: The isocyanate curing agent is prepared by a method including the following steps: dispersing aliphatic isocyanate in an organic solvent, and then slowly adding terminal amino resin to react, thereby obtaining the isocyanate curing agent. The aliphatic isocyanate is at least one selected from hexamethylene diisocyanate trimer, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and methylcyclohexyl diisocyanate; the number average molecular weight of the terminal amino resin is 1000 g / mol to 5000 g / mol; the terminal amino resin is at least one selected from difunctional terminal amino polyether, difunctional terminal amino polytetrahydrofuran, and a mixture of difunctional terminal amino polypropylene oxide.

7. The weather-resistant and corrosion-resistant polyurea coating according to claim 6, characterized in that: The reaction in the preparation method of isocyanate curing agent is carried out at a temperature of 20℃~40℃ for a reaction time of 2h~6h.

8. A method for preparing a weather-resistant and corrosion-resistant polyurea coating as described in any one of claims 1 to 7, characterized in that, Includes the following steps: 1) Mix fluorosilicone modified amino resin, terminal amino resin, amino chain extender, dispersant and defoamer to form component A, and use isocyanate curing agent as component B; 2) Mix component A and component B thoroughly to obtain a weather-resistant and corrosion-resistant polyurea coating.

9. The application of a weather-resistant and corrosion-resistant polyurea coating as described in any one of claims 1 to 7 in the corrosion protection of steel structures.

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