A corrosion protective coating and method for crude oil storage tanks

Abstract

The present application provides a kind of anticorrosive coating composition and corrosion protection coating and corrosion protection method for crude oil storage tank.The coating includes modified polyurethane coating consisting of first component and second component, and high solid content elastic protective weatherable topcoat consisting of third component and fourth component; the raw materials of first component are polyester dihydric alcohol, isocyanate, etc.; the raw materials of second component are chain extender, polyester dihydric alcohol, whisker and catalyst, etc.; the raw materials of third component are polyaspartic ester, methyl ethyl ketone, whisker and coupling agent, etc.; the raw materials of fourth component are curing agent and methyl ethyl ketone.The corrosion protection coating includes modified polyurethane coating and high solid content elastic protective weatherable topcoat coating.The construction period of the corrosion protection coating of the present application is short, environment-friendly, has excellent impact resistance, salt spray resistance, and long protection period, and is suitable for crude oil storage tank, especially tank top and safety accessories in coastal areas.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of anticorrosive coating composition and corrosion protection coating and corrosion protection method for crude oil storage tank, especially relates to a kind of anticorrosive coating composition and corrosion protection coating and corrosion protection method for coastal area storage tank roof and safety accessories, belongs to the field of coating technology. BACKGROUND

[0002] Coastal area air humidity is big, and sodium chloride particles are contained in sea water spray, it is easy to form water film with corrosive on steel surface, to cause the corrosion of crude oil storage tank and other steel structures. At the same time, strong ultraviolet radiation in coastal area and northwest dry and hot area, it also causes the molecular bond of storage tank outer anticorrosive coating to break, causes coating to age prematurely.

[0003] Storage tank roof and safety accessories are at the top of storage tank, and are exposed to the sun for a long time, accumulate water in summer, accumulate snow in winter, and are in a relatively harsh environment for a long time. The conventional way to solve the corrosion of storage tank roof and safety accessories is to spray traditional anticorrosive coating on the metal surface to achieve the effect of preventing corrosion by isolating the metal from the atmosphere. The performance of the coating used in the existing traditional anticorrosive coating of storage tank roof and safety accessories is affected by the performance of the material itself, the quality of the construction process, the environment, etc. The theoretical service life is more than 10 years, but the actual application effect is not satisfactory. Usually, after 5-6 years of use, the coating is damaged to varying degrees, leading to serious corrosion of the storage tank roof and safety accessories. The corrosion of metal storage tanks in coastal areas is even more serious, so the service life of the traditional anticorrosive coating is shorter. In order to ensure the anticorrosive effect, it is necessary to re-spray the coating. Before spraying, the metal substrate needs to be re-sandblasted, which will cause environmental pollution and exceed the standard of pollutant emission, increase the maintenance cost, and require tank cleaning. At the same time, it will also cause the thickness of the metal substrate to be reduced, which poses a certain safety hazard.

[0004] The above situation cannot meet the requirements of long-term stable operation of the storage tank, and does not match the 10-year maintenance cycle of the storage tank, which seriously affects the safe and stable operation of the production and increases the operating and maintenance cost of the storage tank.

[0005] For example, a traditional corrosion protection coating for storage tank roof and safety accessories has a structure as shown in Figure 1 , which has an epoxy zinc phosphate primer layer 2-1 (about 100 μm, 1-2 passes of construction), an epoxy cloud iron intermediate paint layer 3 (about 160 μm, 1-2 passes of construction), and an acrylic polyurethane enamel layer 4 (about 100 μm, 2 passes of construction) on the substrate 1 in sequence. The total thickness of the coating is about 360 μm. Another traditional corrosion protection coating for storage tank roof and safety accessories has a structure as shown in Figure 2As shown, the substrate 1 has an epoxy zinc-rich primer layer 2-2 (80-100 μm, 1-2 passes), an epoxy micaceous iron intermediate paint layer 3 (120-160 μm, 1-2 passes) and an acrylic polyurethane enamel layer 4 (70-100 μm, 2 passes) in sequence, and the total coating thickness is about 270-360 μm.

[0006] Both of the two traditional coating structures need three kinds of paint 4-6 passes to achieve the specified coating thickness, and each pass is spaced apart for more than 24 hours, so the construction period is long. Meanwhile, the traditional anticorrosive coating uses solvent-based paint, which has high volatile organic compounds (VOC) (more than 300 g of volatile organic compounds per square meter of coating), causes harm to the environment and does not meet the current development concept of environmental safety. In addition, the performance of the acrylic polyurethane enamel is greatly affected by the construction environment, and it is sensitive to moisture, so there are often bubbles in the coating, thereby affecting the overall performance of the coating.

[0007] Therefore, the current corrosion protection coating of the tank top and safety accessories of the storage tank cannot meet the long-period stable operation requirements of the storage tank, and has the disadvantages of long construction period, environmental pollution, short protection period, etc. SUMMARY

[0008] To solve the above technical problems, the purpose of the present application is to provide an anticorrosive coating composition and a corrosion protection method for a crude oil storage tank. The corrosion protection coating of the present application has a short construction period, is environmentally friendly, has excellent impact resistance, salt spray resistance and a long protection period.

[0009] To achieve the above purpose, the present application provides an anticorrosive coating composition for a crude oil storage tank, which comprises a modified polyurethane paint and a high-solid-content elastic protective weather-resistant topcoat.

[0010] The modified polyurethane paint comprises a first component and a second component; and the high-solid-content elastic protective weather-resistant topcoat comprises a third component and a fourth component.

[0011] The raw material composition of the first component comprises, in mass parts, 30-40 parts of polyester diol, 50-60 parts of aromatic isocyanate and 0-10 parts of propylene carbonate.

[0012] The raw material composition of the second component comprises, in mass parts, 15-25 parts of chain extender, 45-55 parts of polyether amine, 9-11 parts of polyester diol, 6-8 parts of calcium sulfate whisker, 5-6 parts of multifunctional oxazolidine, 3-4 parts of drying agent and 0.1-0.15 parts of catalyst.

[0013] The raw material composition of the third component includes, in parts by mass, 55-60 parts of polyaspartic ester resin, 4-6 parts of methyl ethyl ketone, 0.2-0.3 parts of defoaming agent, 0.5-0.7 parts of dispersing agent, 12-15 parts of calcium sulfate whisker, 1.5-2 parts of coupling agent, 3-5 parts of multifunctional oxazolidine, and 15-20 parts of colorant;

[0014] The raw material composition of the fourth component includes, in parts by mass, 90-96 parts of elastic curing agent and 4-10 parts of methyl ethyl ketone.

[0015] In the above anticorrosive coating composition, preferably, the first component is prepared by the following steps: in an inert environment, 30-40 parts of polyester diol is heated to 100-120°C under stirring, dehydrated under vacuum negative pressure, then cooled to 50-60°C, 50-60 parts of aromatic isocyanate is added, then reacted at 80-95°C under stirring for 2-3h, cooled to 50-60°C, 0-10 parts of propylene carbonate is added, stirred for 15-30 minutes, to obtain the first component. The first component is a semi-prepolymer. More preferably, the stirring speed is 400-600 rpm.

[0016] In the above anticorrosive coating composition, preferably, the second component is prepared by the following steps: 15-25 parts of chain extender, 45-55 parts of polyether amine, 10 parts of polyester diol, 8 parts of calcium sulfate whisker, 6 parts of multifunctional oxazolidine, 3 parts of drying agent, and 0.1 parts of catalyst are stirred and mixed uniformly, then filtered to obtain the second component. More preferably, the stirring speed is 1000-1500 rpm, the stirring and mixing time is 40-75 minutes, and the filtration is through a 80-120 mesh filter.

[0017] In the above anticorrosive coating composition, preferably, the third component is prepared by the following steps: 55 parts of polyaspartic ester resin, 6 parts of methyl ethyl ketone, 0.2 parts of defoaming agent, and 0.5 parts of dispersing agent are stirred and mixed uniformly at a first stirring speed, then 15 parts of calcium sulfate whisker is added, stirred at a second stirring speed for 30-50 minutes, then 2 parts of coupling agent, 4 parts of multifunctional oxazolidine, and 15-20 parts of colorant are added, stirred at a third stirring speed for 15-30 minutes, to obtain the third component. More preferably, the first stirring speed is 500-800 rpm, and the stirring time at the first stirring speed is 20-40 minutes. More preferably, the second stirring speed is 2500-3500 rpm. More preferably, the third stirring speed is 500-800 rpm.

[0018] In the above anticorrosive coating composition, preferably, the fourth component is prepared by stirring and mixing 90-96 parts by mass of the elastic curing agent and 4-10 parts by mass of methyl ethyl ketone, and then filtering to obtain the fourth component. More preferably, the stirring speed is 200-500 rpm, and the stirring and mixing time is 15-40 minutes, and the filtering is through a 80-120 mesh filter.

[0019] In the above anticorrosive coating composition, preferably, the raw material composition of the first component includes 30-40 parts by mass of polyester diol, 50-60 parts by mass of aromatic isocyanate, and 3-10 parts by mass of propylene carbonate.

[0020] In the above anticorrosive coating composition, preferably, in the raw material composition of the first component, the aromatic isocyanate includes 4,4'-diphenylmethane diisocyanate and / or 2,4'-diphenylmethane diisocyanate, etc. More preferably, the aromatic isocyanate includes a mixture of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate, such as MDI-50.

[0021] In the above anticorrosive coating composition, preferably, in the raw material composition of the second component, the chain extender includes an aromatic diamine chain extender; more preferably, the aromatic diamine chain extender includes diethyl toluene diamine and / or dimethylthio toluene diamine, etc. Particularly preferably, the aromatic diamine chain extender includes a mixture of diethyl toluene diamine and dimethylthio toluene diamine in a mass ratio of (1:2) to (2:1) (preferably 1:1).

[0022] In the above anticorrosive coating composition, preferably, in the raw material composition of the first component and the second component, the polyester diol includes polyester diol L3025, etc.

[0023] In the above anticorrosive coating composition, preferably, in the raw material composition of the second component, the polyether amine includes polyether amine CAT-5000 and / or polyether amine CAD-2000, etc. More preferably, the polyether amine includes a mixture of polyether amine CAT-5000 and polyether amine CAD-2000 in a mass ratio of (1:2) to (1:3).

[0024] In the above anticorrosive coating composition, preferably, in the raw material composition of the second component, the calcium sulfate whisker has a length of 200 microns or less, such as calcium sulfate whisker NP-M02.

[0025] In the above anticorrosive coating composition, preferably, in the raw material composition of the second component, the multifunctional oxazolidine includes bicyclic oxazolidine, such as ALT-202.

[0026] In the above anticorrosive coating composition, preferably, in the raw material composition of the second component, the drying agent includes a molecular sieve drying agent, such as SYLOSIV A3.

[0027] In the above anticorrosive coating composition, preferably, in the raw material composition of the second component, the catalyst includes an organic bismuth catalyst, such as BiCAT8118.

[0028] In the above anticorrosive coating composition, preferably, in the raw material composition of the third component, the polyaspartic ester resin includes polyaspartic ester resin F420 and / or polyaspartic ester resin F524; more preferably, the polyaspartic ester resin includes polyaspartic ester resin F420 and polyaspartic ester resin F524 in a mass ratio of (2:3) to (3:3) (preferably 2.5:3).

[0029] In the above anticorrosive coating composition, preferably, in the raw material composition of the third component, the defoaming agent includes a silicone defoaming agent, such as defoaming agent BYK-023.

[0030] In the above anticorrosive coating composition, preferably, in the raw material composition of the third component, the dispersing agent includes dispersing agent BYK-163 and the like.

[0031] In the above anticorrosive coating composition, preferably, in the raw material composition of the third component, the calcium sulfate whisker has a length of 200 microns or less, such as calcium sulfate whisker NP-M02.

[0032] In the above anticorrosive coating composition, preferably, in the raw material composition of the third component, the coupling agent includes 3-aminopropyl triethoxysilane (KH550) and / or γ-glycidoxypropyl trimethoxysilane (KH560) and the like, more preferably KH560.

[0033] In the above anticorrosive coating composition, preferably, in the raw material composition of the third component, the multifunctional oxazolidine includes bicyclic oxazolidine, such as ALT-202.

[0034] In the above anticorrosive coating composition, in the raw material composition of the third component, the color paste can be a general color paste in the polyurethane industry, and the color includes red, yellow, blue, green, white, black and the like, and the water content is ≤0.5%.

[0035] In the above anticorrosive coating composition, preferably, in the raw material composition of the fourth component, the elastic curing agent includes curing agent GB805B-100.

[0036] In the anticorrosive coating composition described above, preferably, the volume ratio of the first component and the second component is 1:1.

[0037] In the anticorrosive coating composition described above, preferably, the mass ratio of the third component and the fourth component is 1:1.

[0038] In the anticorrosive coating composition of the present application, the first component, the second component, the third component and the fourth component can be packaged and stored separately, mixed and applied according to the volume ratio or mass ratio defined in the present application to obtain a modified polyurethane coating and a high-solid-content elastic protective weather-resistant topcoat, respectively.

[0039] In the anticorrosive coating composition of the present application, calcium sulfate whiskers are used in the raw material composition of the second component and the third component, avoiding the problems of high price and difficult dispersion of nanomaterials; at the same time, the calcium sulfate whiskers are activated twice, that is, the calcium sulfate whiskers preferably used in the present application are active calcium sulfate whiskers, and a coupling agent is used to re-activate them in the dispersion process, so as to ensure that the calcium sulfate whiskers and the organic matrix form a good interface fusion under the action of chemical bonding and physical bonding. When the coating is subjected to external force, the whiskers are easy to deform and stress relax, which helps to absorb and transfer impact energy, and at the same time, due to the equivalent of a short fiber, the whiskers have a long aspect ratio, ultra-high strength and ultra-strong elastic modulus, which play a bridging role in the coating, increase the cohesive strength of the polymer, and thus significantly improve the comprehensive mechanical properties of the coating. In addition, in the raw material composition of the second component, the present application uses a composite drying water-removing agent, using molecular sieves as a physical drying and water-removing component, and using a multifunctional oxazolidine as a chemical water-removing component, which can remove water in the system, convert a small amount of moisture in the air or substrate into a component that can participate in the reaction and form a film during construction, increase the environmental adaptability and storage stability of the coating, and ensure the performance of the coating.

[0040] The second aspect of the present application provides an anticorrosive coating for a crude oil storage tank, which comprises a modified polyurethane coating on the surface of a substrate, and a high-solid-content elastic protective weather-resistant topcoat on the surface of the modified polyurethane coating; wherein the modified polyurethane coating and the high-solid-content elastic protective weather-resistant topcoat are obtained by applying the anticorrosive coating composition described above.

[0041] In the corrosion protection coating described above, preferably, the surface of the substrate is a substrate surface of Sa2.5 standard sand blasting rust removal grade; more preferably, the roughness of the surface of the substrate is 40-75 μm. For the substrate surface of the repair weld and repair area, the person skilled in the art can select the corresponding sand blasting and / or manual electric tool for rust removal and paint removal treatment according to the actual needs to reach the Sa2.5 standard. The sand blasting rust removal grade of the substrate surface of the present application needs to reach the Sa2.5 standard; for the surface defects exposed during the treatment process, the person skilled in the art can polish, fill or treat in an appropriate manner; the roughness of the surface is preferably 40-75 μm.

[0042] In the corrosion protection coating described above, preferably, the substrate includes offshore tank roof and safety accessories.

[0043] In the corrosion protection coating described above, preferably, the thickness of the modified polyurethane coating is 1.2 mm-1.3 mm. More preferably, the modified polyurethane coating is obtained by the following steps: after preheating the first component and the second component, the preheated first component and the second component are mixed and sprayed by using a high-pressure spraying device, the mixing volume ratio of the first component and the second component is 1:1, 1 pass or several passes of construction spraying (more preferably 1-2 passes of construction spraying) is carried out to obtain the modified polyurethane coating, and the thickness of the modified polyurethane coating is 1.2 mm-1.3 mm. The preheating temperature is preferably 50-70°C. The spraying speed is preferably 4-8 kg / min. The high-pressure spraying device used is preferably a two-component high-pressure spraying machine. The person skilled in the art should understand that before construction spraying, the surface of the substrate should be carefully cleaned, and the substrate surface should be completely dried. The substrate surface can be cleaned, dusted and dusted, and the substrate surface should be free of oil stains and other impurities or pollutants; if the substrate surface has defects, it should be repaired before construction spraying. The person skilled in the art should understand that when the modified polyurethane coating is constructed and sprayed, when several passes of construction spraying are carried out, each pass of construction needs to be separated by a period of time, and the next pass of construction spraying is carried out after the coating is dried. The interval time can be 2-3 hours, preferably 2 hours.

[0044] In the corrosion protection coating described above, preferably, the thickness of the high-solid-content elastic protection weather-resistant topcoat is 200-300 μm. More preferably, the high-solid-content elastic protection weather-resistant topcoat is obtained by applying the third component and the fourth component by roller coating or spraying at a mixing mass ratio of 1:1, applying 1 or several coats of the high-solid-content elastic protection weather-resistant topcoat (more preferably, applying 1-2 coats of the high-solid-content elastic protection weather-resistant topcoat), and making the thickness of the high-solid-content elastic protection weather-resistant topcoat 200-300 μm. The third component and the fourth component are applied by roller coating or spraying at room temperature using conventional application methods. It should be understood by those skilled in the art that after the modified polyurethane coating is obtained by application spraying, the high-solid-content elastic protection weather-resistant topcoat is applied after the modified polyurethane coating is dried, and the drying time is preferably 2-3 hours, more preferably 2 hours. It should be understood by those skilled in the art that when the high-solid-content elastic protection weather-resistant topcoat is applied, when several coats of the high-solid-content elastic protection weather-resistant topcoat are applied, each coat is applied after a period of time, the modified polyurethane coating is dried, and then the next coat is applied, and the interval time can be 2-3 hours, preferably 2 hours.

[0045] According to the specific embodiment of the present application, preferably, the release amount of volatile organic compounds (VOC) per square meter of the corrosion protection coating is 12 g or less.

[0046] The present application develops a specific solvent-free modified polyurethane coating and an environmentally friendly high-solid-content elastic protection weather-resistant topcoat, and the corrosion protection coating of the present application can be formed by only two coats. The corrosion protection coating has the advantages of short application cycle and environmental protection, and the coating has excellent impact resistance, salt spray resistance, corrosion resistance and weather resistance, has good protection performance, and the protection time can be 15 years or more, and is suitable for the protection of the roofs of crude oil storage tanks and safety accessories in coastal areas.

[0047] The third aspect of the present application provides a corrosion protection method, which uses the corrosion protection coating composition for crude oil storage tanks described above, and includes the following steps:

[0048] (1) sandblasting and rust removal are performed on the surface of the substrate to achieve a Sa2.5 standard sandblasting and rust removal grade;

[0049] (2) the first component and the second component are preheated, and the preheated first component and the second component are mixed and sprayed using a high-pressure spraying device, the mixing volume ratio of the first component and the second component is 1:1, 1 or several coats of spraying are applied, a modified polyurethane coating is formed on the sandblasted and rust-removed surface of the substrate obtained in step (1), and the thickness of the modified polyurethane coating is 1.2-1.3 mm;

[0050] (3) After drying for 2-3 hours, the third component and the fourth component are roll-coated or spray-coated at a mixing mass ratio of 1:1, 1 pass or several passes of construction roll-coating or spray-coating are performed, a high solid content elastic protective weatherable topcoat layer is formed on the surface of the modified polyurethane coating obtained in step (2), and the thickness of the high solid content elastic protective weatherable topcoat layer is 200-300 μm.

[0051] In the corrosion protection method described above, preferably, the substrate includes offshore tank roof and safety accessories.

[0052] In the corrosion protection method described above, preferably, in step (1), the roughness of the substrate surface after sandblasting and rust removal is 40-75 μm.

[0053] In the corrosion protection method described above, preferably, in step (2), the preheating temperature is 50-70 °C.

[0054] In the corrosion protection method described above, preferably, in step (2), the spray-coating speed is 4-8 kg / min.

[0055] In the corrosion protection method described above, preferably, in step (2), the high pressure spray-coating equipment used is a two-component high pressure spray-coater.

[0056] In the corrosion protection method described above, preferably, in step (2), 1-2 passes of construction spray-coating are performed.

[0057] In the corrosion protection method described above, in step (2), it should be understood by those skilled in the art that, when several passes of construction spray-coating are performed, each pass of construction needs to be separated by a period of time, the next pass of construction spray-coating is performed after the coating layer is dried, and the interval time can be 2-3 hours, preferably 2 hours.

[0058] In the corrosion protection method described above, preferably, in step (3), the drying time is 2 hours.

[0059] In the corrosion protection method described above, preferably, in step (3), 1-2 passes of construction roll-coating or spray-coating are performed.

[0060] In the corrosion protection method described above, in step (3), it should be understood by those skilled in the art that, when several passes of construction roll-coating or spray-coating are performed for the high solid content elastic protective weatherable topcoat layer, each pass of construction needs to be separated by a period of time, the next pass of construction roll-coating or spray-coating is performed after the coating layer is dried, and the interval time can be 2-3 hours, preferably 2 hours.

[0061] The anticorrosive coating composition for crude oil storage tank, the corrosion protection coating and the corrosion protection method have the following excellent technical effects.

[0062] (1) The construction process is simple and short, 2-4 construction processes of the traditional coating are less, only two construction processes can be used, and the interval between each construction process is 2 hours, so that the construction period is greatly shortened.

[0063] (2) The modified polyurethane coating used is 100% solid content solvent-free coating, the finish is an environmentally friendly high solid content coating, and the reduction of construction process can effectively avoid dust pollution caused by paint mist splashing during construction, is green and environmentally friendly, and releases less than 12g of VOC per square meter;

[0064] (3) The protection performance is outstanding, the coating has excellent impact resistance, high tensile strength and high elongation, can meet the daily use, and brings additional mechanical protection performance, reduces the damage to the tank top and safety accessories in the case of accidents or other accidents, and reduces the loss caused by secondary damage, which is a revolutionary performance that traditional protection methods do not have.

[0065] (4) The coating has excellent performance in weather resistance, anti-aging and impact resistance, and has excellent salt spray resistance, corrosion resistance, waterproofness and other protection performance; one coating can achieve a service life of more than 15-18 years, which achieves the super-long life that the traditional coating cannot achieve, and creates conditions for the safe, stable, long-period and environmentally friendly operation of the crude oil storage tank, especially the tank top and safety accessories of the coastal area. BRIEF DESCRIPTION OF DRAWINGS

[0066] Figure 1 It is a structural schematic view of a traditional corrosion protection coating for a tank top and safety accessories.

[0067] Figure 2 It is a structural schematic view of another traditional corrosion protection coating for a tank top and safety accessories.

[0068] Figure 3 It is a structural schematic view of the corrosion protection coating provided in Example 2 of the present application.

[0069] Main component symbol explanation: substrate 1, epoxy zinc phosphate primer layer 2-1, epoxy zinc-rich primer layer 2-2, epoxy iron oxide intermediate paint layer 3, acrylic polyurethane enamel layer 4;

[0070] Sa2.5 standard sandblasting rust removal grade substrate surface 1', modified polyurethane coating 2', high solid content elastic protection weatherable finish coating 3'. DETAILED DESCRIPTION

[0071] In order to have a clearer understanding of the technical features, objectives and benefits of the present application, the technical solutions of the present application are described in detail as follows, but cannot be understood as a limitation on the implementable scope of the present application.

[0072] Embodiment 1

[0073] The embodiment provides a kind of anticorrosive coating composition for crude oil storage tank, the coating composition includes modified polyurethane coating and high solid content elastic protective weatherable finish;Wherein, the modified polyurethane coating includes first component and second component;The volume ratio of the first component and the second component is 1:1;The high solid content elastic protective weatherable finish includes third component and fourth component;The mass ratio of the third component and the fourth component is 1:1.

[0074] The raw material composition of the first component includes 35 parts of polyester diol L3025, 59 parts of MDI-50 (a mixture of 2,4'-diphenyl methane diisocyanate and 4,4'-diphenyl methane diisocyanate) and 6 parts of propylene carbonate by mass fraction;

[0075] The first component is prepared by the following steps: in an inert environment, 35 parts of polyester diol L3025 is heated to 100-120°C under stirring (speed 450 rpm) and dehydrated under vacuum negative pressure, then cooled to 50-60°C, 59 parts of MDI-50 is added, then reacted at 80-95°C under stirring (speed 550 rpm) for 2-3h, cooled to 50-60°C, 6 parts of propylene carbonate is added, stirred for 15 minutes (speed 400 rpm), to obtain a semi-prepolymer, which is the first component.

[0076] The raw material composition of the second component includes 10 parts of dimethylthiophenyl diamine (DMTDA), 10 parts of diethyltoluene diamine (DETDA), 15 parts of polyether amine CAT-5000, 37.9 parts of polyether amine CAD-2000, 10 parts of polyester diol L3025, 8 parts of calcium sulfate whisker NP-M02, 6 parts of bicyclooxazolidine ALT-202, 3 parts of molecular sieve desiccant SYLOSIV A3 and 0.1 parts of organic bismuth catalyst BiCAT8118 by mass fraction;

[0077] The second component is prepared by the following steps: 10 parts of dimethylthiophenyl diamine (DMTDA), 10 parts of diethyl toluene diamine (DETDA), 15 parts of polyether amine CAT-5000, 37.9 parts of polyether amine CAD-2000, 10 parts of polyester diol L3025, 8 parts of calcium sulfate whisker NP-M02, 6 parts of bicyclooxazolidine ALT-202, 3 parts of molecular sieve desiccant SYLOSIV A3 and 0.1 parts of organic bismuth catalyst BiCAT8118 are stirred and uniformly mixed (at a speed of 1500 revolutions per minute for 40 minutes), and then filtered (through a 80-120 mesh filter) to obtain the second component.

[0078] The raw material composition of the third component includes, by mass fraction: 25 parts of polyaspartate resin F420, 30 parts of polyaspartate resin F524, 6 parts of methyl ethyl ketone, 0.2 parts of defoaming agent BYK-023, 0.5 parts of dispersant BYK-163, 15 parts of calcium sulfate whisker NP-M02, 2 parts of coupling agent KH560, 4 parts of bicyclooxazolidine ALT-202, and 1.3 parts of black paste, 16 parts of white paste.

[0079] The third component is prepared by the following steps: 25 parts of polyaspartate resin F420, 30 parts of polyaspartate resin F524, 6 parts of methyl ethyl ketone, 0.2 parts of defoaming agent BYK-023, 0.5 parts of dispersant BYK-163 are stirred and uniformly mixed at a speed of 550 revolutions per minute for 20 minutes, then 15 parts of calcium sulfate whisker NP-M02 is added, stirred at a speed of 3000 revolutions per minute for 30 minutes, then 2 parts of coupling agent KH560, 4 parts of bicyclooxazolidine ALT-202, and 1.3 parts of black paste, 16 parts of white paste are added, stirred at a speed of 500 revolutions per minute for 15 minutes to obtain the third component.

[0080] The raw material composition of the fourth component includes, by mass fraction: 95 parts of elastic curing agent GB805B-100 and 5 parts of methyl ethyl ketone.

[0081] The fourth component is prepared by the following steps: 95 parts of elastic curing agent GB805B-100 and 5 parts of methyl ethyl ketone are stirred and uniformly mixed (at a speed of 500 revolutions per minute for 15 minutes), and then filtered (through a 80-120 mesh filter) to obtain the fourth component.

[0082] In the anticorrosive coating composition for crude oil storage tank of the present embodiment, the first component, the second component, the third component and the fourth component can be packaged and stored separately, mixed and applied according to the above-mentioned volume ratio or mass ratio defined in the present embodiment at the time of use, to obtain the modified polyurethane coating and the high solid content elastic protective weatherable topcoat coating respectively.

[0083] Embodiment 2

[0084] The present embodiment provides an anticorrosive coating for crude oil storage tank, a structural schematic diagram of which is shown in Figure 3 The coating includes a modified polyurethane coating 2' on the surface 1' of the substrate at Sa2.5 standard sand blasting rust removal level, and a high solid content elastic protective weatherable topcoat coating 3' on the surface of the modified polyurethane coating 2';

[0085] The modified polyurethane coating 2' and the high solid content elastic protective weatherable topcoat coating 3' are obtained by applying the anticorrosive coating composition for crude oil storage tank provided in Embodiment 1.

[0086] Specifically, the anticorrosive coating of the present embodiment is prepared by the following method:

[0087] (1) sand blasting the surface of the substrate to reach Sa2.5 standard sand blasting rust removal level, to obtain the surface 1' of the substrate at Sa2.5 standard sand blasting rust removal level, with a roughness of 40-75 μm;

[0088] (2) after preheating the first component and the second component at 50-70°C, mixing and spraying the preheated first component and second component by using a two-component high-pressure sprayer, the volume ratio of the first component to the second component is 1:1, the spraying speed is 5-8 kg / min, and only one pass of construction spraying is performed, to form the modified polyurethane coating 2' on the surface 1' of the substrate at Sa2.5 standard sand blasting rust removal level obtained in step (1), the thickness of the modified polyurethane coating 2' is 1.2 mm-1.3 mm;

[0089] (3) after drying for 2 hours, mixing the third component and the fourth component uniformly according to the mass ratio of 1:1, and then performing conventional room temperature spraying, and only one pass of construction spraying is performed, to form the high solid content elastic protective weatherable topcoat coating 3' on the surface of the modified polyurethane coating 2' obtained in step (2), the thickness of the high solid content elastic protective weatherable topcoat coating 3' is 200 μm-300 μm.

[0090] In the present embodiment, the substrate includes the tank top and safety accessories of crude oil storage tank in coastal areas.

[0091] The volatile organic compound (VOC) release per square meter of the corrosion protection coating of the embodiment is tested to be 12 g or less.

[0092] The performance test of the corrosion protection coating of the embodiment is carried out, and the results are shown in Table 1.

[0093] Table 1

[0094]

[0095] Note: GB-T50393-2017 Steel Oil Storage Tank Anti-corrosion Engineering Technology Standard

[0096] It can be seen that the corrosion protection coating of the embodiment has the advantages of simple construction process, short cycle, environmental protection, etc., and the coating has excellent impact resistance, high tensile strength, high tear strength, and high elongation. At the same time, the coating also has excellent waterproofness, salt spray resistance, corrosion resistance, weather resistance, and medium resistance. The protection performance is good, and the protection time can reach 15 years or more, which is suitable for the protection of the tank top and safety accessories of crude oil storage tanks in coastal areas.

[0097] Comparative Example 1

[0098] In this comparative example, the polyester diol L3025 and the polyether amine in the second component of Example 1 are replaced by polytetrahydrofuran diol (PTMG-1000) to prepare a modified polyurethane coating.

[0099] The raw material composition of the first component includes, by mass fraction, 35 parts of polyester diol L3025, 59 parts of MDI-50 (a mixture of 2,4'-diphenyl methane diisocyanate and 4,4'-diphenyl methane diisocyanate), and 6 parts of propylene carbonate.

[0100] The first component is prepared by the following steps: in an inert environment, 35 parts of polyester diol L3025 are heated to 100-120°C under stirring (speed of 450 revolutions per minute), dehydrated under vacuum negative pressure, then cooled to 50-60°C, and then 59 parts of MDI-50 are added, followed by stirring (speed of 550 revolutions per minute) at 80-95°C for 2-3 hours, cooling to 50-60°C, adding 6 parts of propylene carbonate, and stirring for 15 minutes (speed of 400 revolutions per minute) to obtain a semi-prepolymer, which is the first component.

[0101] The raw material composition of the second component includes, in mass parts, 20 parts of dimethylthiophenyl diamine (DMTDA), 15 parts of diethyl toluene diamine (DETDA), 47.9 parts of polytetrahydrofuran glycol PTMG-1000, 8 parts of calcium sulfate whisker NP-M02, 6 parts of bicyclooxazolidine ALT-202, 3 parts of molecular sieve desiccant SYLOSIV A3, and 0.1 part of organic bismuth catalyst BiCAT8118;

[0102] The second component is prepared by the following steps: 20 parts of dimethylthiophenyl diamine (DMTDA), 15 parts of diethyl toluene diamine (DETDA), 47.9 parts of polytetrahydrofuran glycol PTMG-1000, 8 parts of calcium sulfate whisker NP-M02, 6 parts of bicyclooxazolidine ALT-202, 3 parts of molecular sieve desiccant SYLOSIV A3, and 0.1 part of organic bismuth catalyst BiCAT8118 are stirred and mixed uniformly (at a speed of 1500 revolutions per minute for 40 minutes), and then filtered (through a 80-120 mesh filter) to obtain the second component.

[0103] The modified polyurethane coating prepared in Comparative Example 1 is used instead of the modified polyurethane coating prepared in Example 1, and the corrosion protection coating is prepared according to the method and requirements in Example 2, and the performance of the corrosion protection coating of the present comparative example is tested, and the results are shown in Table 2.

[0104] Table 2

[0105]

[0106] Note: GB-T50393-2017 Steel Oil Storage Tank Corrosion Protection Engineering Technology Standard

[0107] It can be seen that, compared with Example 2, the comprehensive performance of the present comparative example is significantly reduced, and in particular, the adhesion is lower than the index requirement in GB-T50393-2017 Steel Oil Storage Tank Corrosion Protection Engineering Technology Standard.

[0108] Comparative Example 2

[0109] In the present comparative example, the polyester diol L3025 in the first component and the second component of Example 1 is replaced by polycaprolactone diol (PCL220N) to prepare a modified polyurethane coating.

[0110] The raw material composition of the first component includes, in mass parts, 35 parts of polycaprolactone diol (PCL220N), 59 parts of MDI-50 (a mixture of 2,4'-diphenyl methane diisocyanate and 4,4'-diphenyl methane diisocyanate), and 6 parts of propylene carbonate.

[0111] The first component is prepared by the following steps: under inert environment, 35 parts of polycaprolactone diol (PCL220N) is heated to 100-120°C under stirring (speed of 450 r / min), dehydrated under vacuum negative pressure, then cooled to 50-60°C, 59 parts of MDI-50 is added, then reacted at 80-95°C under stirring (speed of 550 r / min) for 2-3h, cooled to 50-60°C, 6 parts of propylene carbonate is added, stirred for 15 minutes (speed of 400 r / min), to obtain a semi-prepolymer, which is the first component.

[0112] The raw material composition of the second component includes, by mass fraction: 10 parts of dimethylthiophenyl diamine (DMTDA), 10 parts of diethyl toluene diamine (DETDA), 15 parts of polyether amine CAT-5000, 37.9 parts of polyether amine CAD-2000, 10 parts of polycaprolactone diol (PCL220N), 8 parts of calcium sulfate whisker NP-M02, 6 parts of bicyclooxazolidine ALT-202, 3 parts of molecular sieve desiccant SYLOSIV A3, and 0.1 parts of organic bismuth catalyst BiCAT8118.

[0113] The second component is prepared by the following steps: 10 parts of dimethylthiophenyl diamine (DMTDA), 10 parts of diethyl toluene diamine (DETDA), 15 parts of polyether amine CAT-5000, 37.9 parts of polyether amine CAD-2000, 10 parts of polycaprolactone diol (PCL220N), 8 parts of calcium sulfate whisker NP-M02, 6 parts of bicyclooxazolidine ALT-202, 3 parts of molecular sieve desiccant SYLOSIV A3, and 0.1 parts of organic bismuth catalyst BiCAT8118 are stirred and mixed uniformly (speed of 1500 r / min, time of 40 minutes), then filtered (through 80-120 mesh filter), to obtain the second component.

[0114] The modified polyurethane coating prepared by Comparative Example 2 is used instead of the modified polyurethane coating prepared by Example 1, and the high solid content elastic protective weatherable topcoat in Example 1 is prepared into a corrosion protective coating according to the method and requirements in Example 2, and the performance of the corrosion protective coating of the present comparative example is tested, and the results are shown in Table 3.

[0115] Table 3

[0116]

[0117] Note: GB-T50393-2017 Steel Oil Storage Tank Corrosion Protection Engineering Technology Standard

[0118] It can be seen that the tensile strength, tear strength, elongation, salt spray resistance, and weather resistance of the coating prepared in this comparative example are all lower than the indicators of Example 2, and in particular, the adhesion is lower than the indicator requirement in the GB-T50393-2017 steel oil storage tank corrosion protection engineering technology standard.

[0119] Comparative Example 3

[0120] In this comparative example, the polyaspartic ester resin F524 in the third component of Example 1 is replaced by polyaspartic ester resin F420 to prepare a protective weather-resistant topcoat.

[0121] The raw material composition of the third component includes, by mass fraction, 55 parts of polyaspartic ester resin F420, 6 parts of methyl ethyl ketone, 0.2 parts of defoaming agent BYK-023, 0.5 parts of dispersing agent BYK-163, 15 parts of calcium sulfate whisker NP-M02, 2 parts of coupling agent KH560, 4 parts of bicyclooxazolidine ALT-202, and 1.3 parts of black paste, 16 parts of white paste.

[0122] The third component is prepared by the following steps: 55 parts of polyaspartic ester resin F420, 6 parts of methyl ethyl ketone, 0.2 parts of defoaming agent BYK-023, and 0.5 parts of dispersing agent BYK-163 are uniformly mixed by stirring at a speed of 550 revolutions per minute for 20 minutes, then 15 parts of calcium sulfate whisker NP-M02 is added, and stirring is carried out at a speed of 3000 revolutions per minute for 30 minutes, then 2 parts of coupling agent KH560, 4 parts of bicyclooxazolidine ALT-202, and 1.3 parts of black paste, 16 parts of white paste are added, and stirring is carried out at a speed of 500 revolutions per minute for 15 minutes to obtain the third component.

[0123] The raw material composition of the fourth component includes, by mass fraction, 95 parts of elastic curing agent GB805B-100 and 5 parts of methyl ethyl ketone.

[0124] The fourth component is prepared by the following steps: 95 parts of elastic curing agent GB805B-100 and 5 parts of methyl ethyl ketone are uniformly mixed by stirring (speed of 500 revolutions per minute, time of 15 minutes), and then filtered (through a 80-120 mesh filter) to obtain the fourth component.

[0125] The modified polyurethane coating prepared in Example 1 is used together with the protective weather-resistant topcoat in this comparative example to prepare a corrosion protection coating according to the method and requirements in Example 2, and the performance of the corrosion protection coating in this comparative example is tested, and the results are shown in Table 4.

[0126] Table 4

[0127]

[0128]

[0129] Note: GB-T50393-2017 Steel Oil Storage Tank Anti-corrosion Engineering Technology Standard

[0130] It can be seen that the tensile strength, tear strength, elongation, salt spray resistance and weather resistance of the coating prepared in the present comparative example are all lower than those of Example 2, especially the salt spray resistance and weather resistance are significantly reduced.

Claims

1. A corrosion protection coating composition for crude oil storage tank, the coating composition comprising a modified polyurethane coating and a high solid content elastic protective weatherable topcoat; wherein the modified polyurethane coating comprising a first component and a second component; the high solid content elastic protective weatherable topcoat comprising a third component and a fourth component; the raw material composition of the first component comprises, in parts by mass, 30-40 parts of polyester diol, 50-60 parts of aromatic isocyanate and 0-10 parts of propylene carbonate; the polyester diol comprises polyester diol L3025; the raw material composition of the second component comprises, in parts by mass, 15-25 parts of chain extender, 45-55 parts of polyether amine, 9-11 parts of polyester diol, 6-8 parts of calcium sulfate whisker, 5-6 parts of multifunctional oxazolidine, 3-4 parts of molecular sieve drier and 0.1-0.15 parts of catalyst; the polyester diol comprises polyester diol L3025; the raw material composition of the third component comprises, in parts by mass, 55-60 parts of polyaspartic ester resin, 4-6 parts of methyl ethyl ketone, 0.2-0.3 parts of defoaming agent, 0.5-0.7 parts of dispersant, 12-15 parts of calcium sulfate whisker, 1.5-2 parts of coupling agent, 3-5 parts of multifunctional oxazolidine and 15-20 parts of color paste; the polyaspartic ester resin comprises polyaspartic ester resin F420 and polyaspartic ester resin F524 in a mass ratio of (2:3) to (3:3); the raw material composition of the fourth component comprises, in parts by mass, 90-96 parts of elastic curing agent and 4-10 parts of methyl ethyl ketone.

2. The anticorrosive coating composition according to claim 1, wherein, the first component is prepared by the following steps: in an inert environment, 30-40 parts of polyester diol is heated to 100-120℃ under stirring, dehydrated under vacuum negative pressure, then cooled to 50-60℃, 50-60 parts of aromatic isocyanate is added, then reacted at 80-95℃ under stirring for 2-3h, cooled to 50-60℃, 0-10 parts of propylene carbonate is added, stirred for 15-30 minutes, to obtain the first component.

3. The anticorrosive coating composition according to claim 1, wherein, the second component is prepared by the following steps: 15-25 parts of chain extender, 45-55 parts of polyether amine, 10 parts of polyester diol, 8 parts of calcium sulfate whisker, 6 parts of multifunctional oxazolidine, 3 parts of molecular sieve drier and 0.1 parts of catalyst are stirred and mixed uniformly, then filtered to obtain the second component.

4. The anticorrosive coating composition according to claim 1, wherein, the third component is prepared by the following steps: 55 parts of polyaspartic ester resin, 6 parts of methyl ethyl ketone, 0.2 parts of defoaming agent and 0.5 parts of dispersant are stirred and mixed uniformly at a first stirring speed, then 15 parts of calcium sulfate whisker is added, stirred at a second stirring speed for 30-50 minutes, then 2 parts of coupling agent, 4 parts of multifunctional oxazolidine and 15-20 parts of color paste are added, stirred at a third stirring speed for 15-30 minutes, to obtain the third component.

5. The anticorrosive coating composition according to claim 4, wherein, the first stirring speed is 500-800 revolutions per minute, and the stirring time at the first stirring speed is 20-40 minutes.

6. The anticorrosive coating composition according to claim 4, wherein, the second stirring speed is 2500-3500 revolutions per minute.

7. The anticorrosive coating composition according to claim 4, wherein, The third rotating speed is 500-800 rpm.

8. The anticorrosive coating composition according to claim 1, wherein, The fourth component is prepared by mixing 90-96 parts of the elastic curing agent and 4-10 parts of methyl ethyl ketone by mass fraction, and then filtering to obtain the fourth component.

9. The anticorrosive coating composition according to claim 1, wherein, The raw material composition of the first component includes 30-40 parts of polyester diol, 50-60 parts of aromatic isocyanate, and 3-10 parts of propylene carbonate by mass fraction.

10. The anticorrosive coating composition according to claim 1, wherein, In the raw material composition of the first component, the aromatic isocyanate includes 4,4'-diphenyl methane diisocyanate and / or 2,4'-diphenyl methane diisocyanate.

11. The anticorrosive coating composition according to claim 1, wherein, In the raw material composition of the second component, the chain extender includes an aromatic diamine chain extender.

12. The anticorrosive coating composition according to claim 11, wherein, In the raw material composition of the second component, the aromatic diamine chain extender includes diethyl toluene diamine and / or dimethylthio toluene diamine.

13. The anticorrosive coating composition according to claim 12, wherein, In the raw material composition of the second component, the aromatic diamine chain extender includes a mixture of diethyl toluene diamine and dimethylthio toluene diamine in a mass ratio of (1:2) to (2:1).

14. The anticorrosive paint composition according to claim 1, wherein, In the raw material composition of the second component, the polyether amine includes polyether amine CAT-5000 and / or polyether amine CAD-2000.

15. The anticorrosive coating composition according to claim 14, wherein, In the raw material composition of the second component, the polyether amine includes a mixture of polyether amine CAT-5000 and polyether amine CAD-2000 in a mass ratio of (1:2) to (1:3).

16. The anticorrosive paint composition according to claim 1, wherein, In the raw material composition of the second component, the calcium sulfate whisker has a length of 200 microns or less.

17. The anticorrosive paint composition according to claim 1, wherein, In the raw material composition of the second component, the multi-functional oxazolidine includes bicyclic oxazolidine.

18. The anticorrosive paint composition according to claim 1, wherein, In the raw material composition of the second component, the catalyst includes an organic bismuth catalyst.

19. The anticorrosive paint composition according to claim 1, wherein, In the raw material composition of the third component, the defoaming agent includes a silicone defoaming agent.

20. The anticorrosive paint composition according to claim 1, wherein, In the raw material composition of the third component, the dispersant includes dispersant BYK-163.

21. The anticorrosive paint composition according to claim 1, wherein, In the raw material composition of the third component, the calcium sulfate whisker has a length of 200 microns or less.

22. The anticorrosive paint composition according to claim 1, wherein, In the raw material composition of the third component, the coupling agent includes 3-aminopropyl triethoxysilane and / or γ-glycidoxypropyl trimethoxysilane.

23. The anticorrosive paint composition according to claim 1, wherein, In the raw material composition of the third component, the multi-functional oxazolidine includes bicyclic oxazolidine.

24. The anticorrosive paint composition according to claim 1, wherein, In the raw material composition of the fourth component, the elastic curing agent includes curing agent GB805B-100.

25. The anticorrosive paint composition according to claim 1, wherein, The volume ratio of the first component and the second component is 1:

1.

26. The anticorrosive paint composition according to claim 1, wherein, The mass ratio of the third component and the fourth component is 1:

1.

27. A corrosion protection coating for a crude oil storage tank comprising a modified polyurethane coating on a substrate surface, and a high solids, elastomeric, protective, weatherable topcoat coating on the surface of the modified polyurethane coating; wherein, The modified polyurethane coating and the high-solid-content elastic protective weather-resistant topcoat are obtained by applying the anticorrosive coating composition for crude oil storage tanks according to any one of claims 1-26.

28. The corrosion protective coating of claim 27, wherein, The surface of the substrate is a substrate surface of Sa2.5 standard sand blasting rust removal grade.

29. The corrosion protection coating of claim 27 or 28, wherein, The roughness of the surface of the substrate is 40-75 microns.

30. The corrosion protective coating of claim 27, wherein, The substrate includes a coastal area storage tank roof and safety accessories.

31. The corrosion protective coating of claim 27, wherein, The thickness of the modified polyurethane coating is 1.2-1.3 mm.

32. The corrosion protective coating of claim 27 or 31, wherein, The modified polyurethane coating is obtained by the following steps: the first component and the second component are preheated, and then the preheated first component and the second component are mixed and sprayed by using a high-pressure spraying device, the mixed volume ratio of the first component and the second component is 1:1, 1 or several construction sprayings are carried out, the modified polyurethane coating is obtained, and the thickness of the modified polyurethane coating is 1.2mm-1.3mm.

33. The corrosion protective coating of claim 27, wherein, The thickness of the high-solid-content elastic protective weatherable topcoat is 200μm-300μm.

34. The corrosion protective coating of claim 27 or 33, wherein, The high-solid-content elastic protective weatherable topcoat is obtained by the following steps: the third component and the fourth component are roll-coated or sprayed according to a mixing mass ratio of 1:1, 1 or several construction roll-coating or spraying is carried out, the high-solid-content elastic protective weatherable topcoat is obtained, and the thickness of the high-solid-content elastic protective weatherable topcoat is 200μm-300μm.

35. The corrosion protective coating of claim 27, wherein, The release amount of volatile organic compounds per square meter of the corrosion protection coating is 12g or less.

36. A corrosion protection method, the method using the anticorrosive coating composition for crude oil storage tanks according to any one of claims 1-26, comprising the following steps: (1) sandblasting the surface of the substrate to achieve a Sa2.5 standard sandblasting rust removal level; (2) the first component and the second component are preheated, and then the preheated first component and the second component are mixed and sprayed by using a high-pressure spraying device, the mixed volume ratio of the first component and the second component is 1:1, 1 or several construction sprayings are carried out, a modified polyurethane coating is formed on the sandblasted substrate surface obtained in step (1), and the thickness of the modified polyurethane coating is 1.2mm-1.3mm; (3) after drying for 2-3 hours, the third component and the fourth component are roll-coated or sprayed according to a mixing mass ratio of 1:1, 1 or several construction roll-coating or spraying is carried out, a high-solid-content elastic protective weatherable topcoat is formed on the surface of the modified polyurethane coating obtained in step (2), and the thickness of the high-solid-content elastic protective weatherable topcoat is 200μm-300μm.

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