A non-fluoro-repellent polyurea anticorrosive coating for petrochemical pipelines and its preparation method and application

Abstract

The present application relates to the technical field of petrochemical pipeline anticorrosive coating, and discloses a non-fluorine oil-repellent polyurea anticorrosive coating for petrochemical pipeline, a preparation method and application thereof. The method comprises the following steps: spraying A component and B component on a substrate to form a polyurea coating, then continuously spraying a weak polar solvent on the polyurea coating, and then volatilizing the weak polar solvent, wherein the A component is a polyurea prepolymer, and the B component contains a polyether polyamine, a polydimethylsiloxane, a chain extender and an auxiliary agent. The non-fluorine oil-repellent polyurea anticorrosive coating prepared by the method has strong oil-repellent property and substrate adhesion, and the oil-repellent surface is resistant to scratching, has strong mechanical stability and chemical stability, and is free of fluorine, non-toxic, harmless and friendly to the environment.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating technology for petrochemical pipelines, specifically to a non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines, its preparation method, and its application. Background Technology

[0002] Pipeline leaks are a major cause of soil and groundwater pollution in oil and petrochemical enterprises, making it crucial to improve pipeline corrosion resistance to prevent contamination in these sites. Oily substances transported in pipelines, due to their low surface tension, readily adhere to the pipeline surface, leading to blockages and corrosion leaks. Polyurea elastomers are high-molecular-weight polymers with urea bonds, obtained by reacting isocyanate prepolymers and amino compounds. Because polyurea coatings can limit the interaction between the metal or alloy substrate and corrosive substances (such as water and ions), ensuring the long-term stability and reliability of the metal or alloy, they have been widely used as anti-corrosion materials in various industrial settings in recent years. However, they do not repel low-surface-tension oily substances; therefore, this material cannot effectively protect petrochemical pipelines. Improving its oleophobic properties and developing efficient and relatively inexpensive oleophobic polyurea anti-corrosion coatings suitable for petrochemical pipelines is an effective method for controlling pollution sources from oil and petrochemical pipeline leaks.

[0003] Oleophobic materials have significant applications in self-cleaning, oil / water separation, anti-bioadhesion, guiding oil droplet movement, corrosion protection, and oil stain removal. Oleophobic surfaces are often achieved through specialized rough structures, typically composed of micro / nano-sized particles. However, these rough structures generally exhibit poor mechanical stability, are not scratch-resistant, have high production costs, and are difficult to mass-produce industrially. Furthermore, these specialized rough surface structures are easily wetted by liquids, causing the coating to lose its oleophobic properties. Another method for constructing oleophobic surfaces is to introduce low surface energy components into the coating surface, thereby endowing it with good oleophobic properties. Currently, the most commonly introduced low surface energy components are fluorinated groups; however, fluorinated materials may be harmful to the environment and human health, and low surface energy fluorinated components have poor adhesion to most substrates, thus limiting the practical application of oleophobic coatings. Organosilicon, as a low-toxicity, low surface energy material, has the potential to replace fluorinated compounds in various fields. Moreover, its hydrophobicity, excellent chemical stability, and thermal stability make it an ideal choice for constructing polyurea oleophobic surfaces.

[0004] For example, patent application CN109207039B discloses a fluorinated modified aspartic polyurea coating and its preparation method. This invention combines the advantages of aspartic polyurea and fluorocarbon coatings. The coating prepared with fluorinated modified fluorinated aspartic ester resin can significantly reduce the surface water contact angle, reducing water wetting and erosion of the paint film. However, the fluorinated raw materials used in this method are environmentally harmful, and the adhesion of fluorinated materials to most substrates is poor.

[0005] Patent application CN108219146A discloses a silicone-modified polyurea (polyurethane) elastomer and its preparation method. It uses an amino-terminated polyether-polysiloxane-polyether block copolymer as the soft segment to prepare a polyurea with high mechanical properties. This method improves its mechanical properties by introducing polysiloxane into the polyurea molecular chain through copolymerization. However, this method does not introduce silicone to the surface of the coating, thus failing to significantly improve its surface oleophobic properties.

[0006] Patent application CN107298930B discloses a method for preparing and using an organosilicon-polyurea self-layering coating. This method includes two parts: the preparation of an organosilicon-modified polyurethane curing agent component and the preparation of a silicone-containing resin component. However, the layering mechanism between the organosilicon and the substrate is not clear in this invention. The oleophobicity of the coating surface is not significant, and it is only due to the self-rotation of the organosilicon segments in the polymer molecular chain during the curing process.

[0007] The literature "Synthesis and Performance Study of Epoxy Silicone Oil Modified Polyaspartic Ester Polyurea" synthesized organosilicon modified polyaspartic ester (PAE-S). However, this literature copolymerized organosilicon in the polyurea segments to enhance its mechanical properties, without introducing the organosilicon to the coating surface, resulting in poor oleophobicity of the coating. Summary of the Invention

[0008] The purpose of this invention is to overcome the problems of easy oil adhesion, easy corrosion, and difficulty in removing oil stains in existing petrochemical pipelines, and to provide a non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines, its preparation method, and its application.

[0009] The inventors of this invention discovered that existing silicone-modified polyurea primarily aims to improve the mechanical properties of the polyurea coating without introducing the silicone to the coating surface, thus neglecting the oleophobic properties of the polyurea coating. Therefore, the inventors creatively migrated a portion of polydimethylsiloxane (PDMS) to the coating surface, unexpectedly discovering that this not only improves the oleophobicity of the polyurea coating but also maintains high stability of the PDMS oleophobic segments on the surface, thus completing this invention.

[0010] To achieve the above objectives, the present invention provides a method for preparing a non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines. The method includes: spraying component A and component B onto a substrate to form a polyurea coating; then continuously spraying a weakly polar solvent onto the polyurea coating; and then allowing the weakly polar solvent to evaporate. Component A is a polyurea prepolymer, and component B contains polyether polyamine, polydimethylsiloxane, chain extender, and additives.

[0011] Preferably, the volume ratio of component A to component B is 1:1-1.8, more preferably 1:1.1-1.5.

[0012] Preferably, the thickness of the formed polyurea coating is 1-4 mm, more preferably 1.8-2.5 mm.

[0013] Preferably, the weakly polar solvent is one or any combination of at least two of acetone, n-hexane, and toluene.

[0014] Preferably, the spraying amount of the weakly polar solvent is 0.4-1 g / cm³. 2 The continuous spraying time for weakly polar solvents is 0.5-3 hours.

[0015] Preferably, the method further includes: after the weakly polar solvent has evaporated, curing it at 200-250°C and 30-60% relative humidity for 3-15 days.

[0016] Preferably, the method further includes preparing component A by prepolymerizing polyisocyanate and polyether polyol according to the following steps:

[0017] Preferably, the prepolymerization reaction is carried out at a temperature of 70-90°C for 1-5 hours.

[0018] Preferably, the total amount of the polyisocyanate and the polyether polyol is 100 parts by weight, the amount of the polyether polyol is 30-60 parts by weight, and the amount of the polyisocyanate is 40-70 parts by weight.

[0019] Preferably, the polyisocyanate is an aromatic diisocyanate, more preferably one or more combinations of 4,4-diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI) and 1,5-naphthalene diisocyanate (NDI).

[0020] Preferably, the polyether polyol is one or more of polypropylene glycol, polyethylene glycol, and polyglycerol.

[0021] Preferably, in component B, relative to 100 parts by weight of the polyether polyamine, the content of the chain extender is 50-90 parts by weight, the content of the polydimethylsiloxane is 20-110 parts by weight, and the content of the additives is 10-50 parts by weight.

[0022] Preferably, the polyether polyamine is one or more of polyoxyethylene diamine, polyoxypropylene diamine, and polytetramethylene ether diamine, or any combination thereof.

[0023] Preferably, the chain extender is an amine chain extender, preferably one or more of 3,5-diethyltoluenediamine, 4,4-bis-sec-butylaminodiphenylmethane, poly(1,4-butanediol)bis(4-aminobenzoate) and 3,3'-dimethyl-4,4'-diaminodicyclohexanemethane, in any combination of two or more.

[0024] Preferably, the additives contain defoamers, leveling agents, coupling agents, dispersants, and antioxidants.

[0025] The present invention also provides a non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines prepared by the above method.

[0026] The present invention also provides a petrochemical pipeline, which includes a pipeline substrate and a coating formed on the surface of the pipeline substrate, wherein the coating is a non-fluorinated oleophobic polyurea anti-corrosion coating prepared according to the above method.

[0027] In this invention, the upward force during solvent evaporation can be used to cause the flexible PDMS molecular chains to migrate to the surface, thereby significantly improving the surface oleophobic properties.

[0028] The non-fluorinated oleophobic polyurea anti-corrosion coating prepared according to the method of the present invention has strong oleophobicity and substrate adhesion, scratch resistance of the oleophobic surface, strong mechanical and chemical stability, and is fluorine-free, non-toxic, harmless and environmentally friendly.

[0029] Moreover, the non-fluorinated oleophobic polyurea anti-corrosion coating can be prepared using a one-time spraying method, which is simple to apply and can solve problems such as pipeline corrosion and seepage prevention for petrochemical enterprises. Therefore, it has broad application prospects in the fields of self-cleaning, corrosion protection, and oil stain removal. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the contact angle of the non-fluorinated oleophobic polyurea anti-corrosion coating prepared in Example 2 of the present invention;

[0031] Figure 2 The infrared spectra of the non-fluorinated oleophobic polyurea anti-corrosion coatings prepared in Comparative Example 1 and Example 2 are shown.

[0032] Figure 3 The stress-strain curve of the non-fluorinated oleophobic polyurea anti-corrosion coating prepared in Example 2 of the present invention is shown. Detailed Implementation

[0033] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0034] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0035] The method for preparing a non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines according to the present invention includes: spraying component A and component B onto a substrate to form a polyurea coating; then continuously spraying a weakly polar solvent onto the polyurea coating; and finally allowing the weakly polar solvent to evaporate. Component A is a polyurea prepolymer, and component B contains polyether polyamine, polydimethylsiloxane (PDMS), chain extender, and additives. In this method, the upward force generated during the evaporation of the weakly polar solvent causes the flexible PDMS molecular chains to migrate to the surface, thereby significantly improving the surface oleophobic properties.

[0036] In the method described in this invention, the volume ratio of component A to component B can be 1:1-1.8, preferably 1:1.1-1.5.

[0037] In the method described in this invention, the thickness of the polyurea coating formed can be 1-4 mm, preferably 1.8-2.5 mm.

[0038] In the method described in this invention, the weakly polar solvent can be a solvent that is volatile at room temperature, miscible with PDMS molecular chains, and incompatible with polyurea molecular chains. Preferably, the weakly polar solvent is one or any combination of at least two of acetone, n-hexane, and toluene.

[0039] In the method described in this invention, the spraying amount of the weakly polar solvent can be 0.4-1 g / cm³. 2 The preferred concentration is 0.6-0.8 g / cm³. 2 .

[0040] In the method described in this invention, the continuous spraying time of the weakly polar solvent can be 0.5-3h, preferably 0.8-1.5h.

[0041] In the method described in this invention, the solvent evaporation process can be carried out at room temperature, and the evaporation time can typically be from 10 hours to 2 days.

[0042] In a preferred embodiment, the preparation method of the non-fluorinated oleophobic polyurea anti-corrosion coating further includes: after the weakly polar solvent evaporates, curing it for 3-15 days (most preferably 5-10 days) at 200-250℃ (most preferably 230℃) and relative humidity of 30-60% (most preferably 50%).

[0043] In the method described in this invention, the process of spraying component A and component B onto a substrate may include: injecting component A and component B into an isocyanate compound reservoir and an amine compound reservoir, respectively; heating to 75-90°C (most preferably 80°C); selecting a spray gun pressure of 15-20 MPa (most preferably 17 MPa); setting the volume ratio of component A to component B to be 1:1.1-1.5; and spraying the substrate to form a polyurea coating. In one specific embodiment, the spraying machine used in the spraying process is a Gusmer H20 / 35 high-pressure airless sprayer, and the spray gun used is a GX-7 spray gun.

[0044] In the method described in this invention, the polyurea prepolymer, which is component A, can be prepared according to conventional methods. In a specific embodiment, the method for preparing the non-fluorinated oleophobic polyurea anti-corrosion coating further includes preparing component A by prepolymerizing a polyisocyanate and a polyether polyol. The conditions for the prepolymerization reaction may include a temperature of 70-90°C and a time of 1-5 hours.

[0045] In a preferred embodiment, the polyether polyol is first dehydrated before participating in the prepolymerization reaction. The dehydration process may include: vacuum dehydrating the polyether polyol at 90-100°C for 3-8 hours. Preferably, the dehydration process results in a water content of less than 0.05% for the polyether polyol.

[0046] In another preferred embodiment, the endpoint of the prepolymerization reaction is controlled by detecting the NCO group content in the product. Specifically, the reaction is stopped when the NCO group content in the prepolymer product reaches 15%. The NCO group content in the prepolymer product can be determined according to the method in GB / T 12009.4.

[0047] In the prepolymerization process, the total amount of the polyisocyanate and the polyether polyol is 100 parts by weight, the amount of the polyether polyol can be 30-60 parts by weight, preferably 40-50 parts by weight; the amount of the polyisocyanate can be 40-70 parts by weight, preferably 50-60 parts by weight.

[0048] In this invention, the polyisocyanate is preferably an aromatic diisocyanate, more preferably one or more combinations of 4,4-diphenylmethane diisocyanate, toluene diisocyanate and 1,5-naphthalene diisocyanate.

[0049] In this invention, the polyether polyol is preferably one or more of polypropylene glycol, polyethylene glycol, and polyglycerol, and more preferably polypropylene glycol. More preferably, the polypropylene glycol has a number-average molecular weight of 400-3000, more preferably 1500-2500, and most preferably 2000.

[0050] In this invention, in component B, relative to 100 parts by weight of the polyether polyamine, the content of the chain extender can be 50-90 parts by weight, the content of the polydimethylsiloxane can be 20-110 parts by weight, and the content of the additives can be 10-50 parts by weight.

[0051] In this invention, the number average molecular weight of the polydimethylsiloxane can be 1000-8000, preferably 2000-5000, and most preferably 3000.

[0052] In this invention, the polyether polyamine is one or more of polyoxyethylene diamine, polyoxypropylene diamine, and polytetramethylene ether diamine, preferably polyoxypropylene diamine. In a more preferred embodiment, the polyether polyamine is a combination of polyether polyamine T-5000 and polyether polyamine D-2000. More preferably, the weight ratio of polyether polyamine T-5000 to polyether polyamine D-2000 is 2-6:1, and most preferably 4:1.

[0053] In this invention, the chain extender is preferably an amine chain extender, more preferably one or more combinations of 3,5-diethyltoluenediamine, 4,4-bis-sec-butylaminodiphenylmethane, poly(1,4-butanediol)bis(4-aminobenzoate), and 3,3'-dimethyl-4,4'-diaminodicyclohexanemethane. In a preferred embodiment, the chain extender is a combination of 3,5-diethyltoluenediamine and 4,4-bis-sec-butylaminodiphenylmethane. More preferably, the weight ratio of 3,5-diethyltoluenediamine to 4,4-bis-sec-butylaminodiphenylmethane is 1:1-2, and most preferably 1:1.5.

[0054] In this invention, preferably, the additives contain an defoamer, a leveling agent, a coupling agent, a dispersant, and an antioxidant. The defoamer, leveling agent, coupling agent, dispersant, and antioxidant can be added in amounts conventionally used in the art. In a specific embodiment, relative to 100 parts by weight of the polyether polyamine, the amount of the defoamer is 3-6 parts by weight, the amount of the leveling agent is 1-4 parts by weight, the amount of the coupling agent is 1-4 parts by weight, the amount of the dispersant is 3-6 parts by weight, and the amount of the antioxidant is 1-4 parts by weight.

[0055] In this invention, the type of defoamer is not particularly limited and can be a conventional choice in the art. In a specific embodiment, the defoamer is selected from one or any combination of at least two of the commercially available BYK-085, BYK-066N, BYK-1790, and BYK-052N from BYK Chemical Company.

[0056] In this invention, the type of leveling agent is not particularly limited and can be any conventional choice in the art. In a specific embodiment, the leveling agent is selected from one or any combination of at least two of the commercially available BYK 300, BYK 306, and BYK 333 from BYK Chemical Company.

[0057] In this invention, the type of coupling agent is not particularly limited and can be a conventional choice in the art. In a specific embodiment, the coupling agent is selected from one or any combination of at least two of the commercially available silane coupling agents KH-171, KH-580, KH-602 and KH-792.

[0058] In this invention, the type of dispersant is not particularly limited and can be a conventional choice in the art. In a specific embodiment, the dispersant is selected from one or any combination of at least two of polycarboxylate, polymethacrylic acid derivatives, and maleic anhydride copolymers.

[0059] In this invention, the type of antioxidant is not particularly limited and can be a conventional choice in the art. In a specific embodiment, the antioxidant is selected from one or any combination of at least two of commercially available antioxidants 1010, 1076, and 164.

[0060] In one specific embodiment, the method for preparing the non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines includes the following steps:

[0061] (1) The polyether polyol is vacuum dehydrated at 90-100℃ for 3-8h to make the water content of the polyether polyol less than 0.05%. Then, the dehydrated polyether polyol is prepolymerized with aromatic diisocyanate in a protective gas (such as nitrogen). The NCO group content is determined according to GB / T 12009.4. When it reaches 15%, the reaction is stopped to obtain polyurea prepolymer, i.e. component A.

[0062] (2) Mix the polyether polyamine, amine chain extender, polydimethylsiloxane and additives, and then dehydrate them under vacuum to make the water content less than 0.05% to obtain component B;

[0063] (3) Spray the A component and the B component onto the substrate at a volume ratio of 1:1.1-1.5 to form a polyurea coating. Then, continuously spray weakly polar solvents such as acetone, n-hexane, and toluene onto the polyurea coating for 0.5-3 hours. Allow the solvents to slowly evaporate at room temperature for 10 hours to 2 days. After the solvents have evaporated, cure the coating at 200-250°C and 30-60% relative humidity for 3-15 days to obtain a non-fluorinated oleophobic polyurea anti-corrosion coating.

[0064] In another specific embodiment, the method for preparing the non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines includes the following steps:

[0065] (1) Add 40-50 parts by weight of polypropylene glycol (PPG, analytical grade, M) n =2000) was vacuum dehydrated at 90-100℃ for 3-8 hours to reduce the water content to less than 0.05%; the dehydrated polypropylene glycol was then reacted with 50-60 parts by weight of 4,4-diphenylmethane diisocyanate (MDI, analytical grade) at 70-90℃ under nitrogen atmosphere. n =250) Keep the reaction at a temperature of 1-5h, and determine the NCO group content according to GB / T 12009.4. Stop the reaction when it reaches 15% to obtain polyurea prepolymer, i.e. component A, and store it under nitrogen.

[0066] (2) Polyether polyamine T-5000 (analytical grade, M) n =5000), polyether polyamine D-2000 (analytical grade, M n =2000), amine chain extender 3,5-diethyltoluenediamine (E100, analytical grade, M n =89), amine chain extender 4,4-bis-sec-butylaminodiphenylmethane (W6200, analytical grade, M n =155), polydimethylsiloxane (PDMS, analytical grade, M n =3000) and additives are stirred evenly in a high-speed disperser and then vacuum dehydrated in a reaction vessel for 1-5 hours to reduce the water content to less than 0.05% to obtain component B, which is then stored under nitrogen.

[0067] (3) Spray the A component and the B component onto the substrate at a volume ratio of 1:1.1-1.5 to form a polyurea coating. Then, continuously spray weakly polar solvents such as acetone, n-hexane, and toluene onto the polyurea coating for 0.5-3 hours. Allow the solvents to slowly evaporate at room temperature for 10 hours to 2 days. After the solvents have evaporated, cure the coating at 200-250°C and 30-60% relative humidity for 3-15 days to obtain a non-fluorinated oleophobic polyurea anti-corrosion coating.

[0068] The present invention also provides a non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines prepared by the above method. The non-fluorinated oleophobic polyurea anti-corrosion coating exhibits strong oleophobicity and substrate adhesion, scratch resistance on the oleophobic surface, strong mechanical and chemical stability, and is fluorine-free, non-toxic, harmless, and environmentally friendly.

[0069] The present invention also provides a petrochemical pipeline, which includes a pipeline substrate and a coating formed on the surface of the pipeline substrate, wherein the coating is a non-fluorinated oleophobic polyurea anti-corrosion coating prepared according to the above method.

[0070] Petrochemical pipelines are primarily used to transport oily substances. Oils, with their low surface energy, easily adhere to substrate surfaces, and the sulfur compounds in the oil can corrode the substrate, leading to leaks. In my country, corrosion accounts for approximately 30% of pipeline accidents. The non-fluorinated oleophobic polyurea anti-corrosion coating prepared according to the method described in this invention possesses strong oleophobicity and substrate adhesion, scratch resistance on the oleophobic surface, high mechanical and chemical stability, and is fluorine-free, non-toxic, and environmentally friendly.

[0071] Moreover, the non-fluorinated oleophobic polyurea anti-corrosion coating can be prepared using a one-time spraying method, which is simple to apply and can solve problems such as pipeline corrosion and seepage prevention for petrochemical enterprises. Therefore, it has broad application prospects in the fields of self-cleaning, corrosion protection, and oil stain removal.

[0072] The following examples further illustrate the non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines, its preparation method, and its application. These examples are implemented based on the technical solution of this invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of this invention is not limited to the following examples.

[0073] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0074] The test characterization methods in the following embodiments are as follows:

[0075] (1) Adhesion test

[0076] The adhesion of the coating sprayed onto the surface of the metal sheet was tested using a manual coating adhesion tester (model: ZPTC-10S, Shijiazhuang Zhuopu Technology Co., Ltd.), and the coating adhesion was obtained according to the pull-off method of GB / T 5210.

[0077] (2) Mechanical properties

[0078] The tensile and tear properties of the coating were tested using an electronic universal testing machine (model: CMT4204, Shenzhen Xin Sansi Materials Testing Co., Ltd.). The sensor was set to 5kN, the tensile speed to 500mm / min, the sample size to be 120mm×4mm×2mm, and the clamping distance to be 20mm. Tensile strength and elongation at break were tested according to GB / T 528-1998, and tear strength was tested according to GB / T 529-2008.

[0079] (3) Hardness

[0080] The coating hardness was tested using a Shore hardness tester (model: LX-D, Shanghai Liuling Instrument Factory) according to GB / T 531.1-2008.

[0081] (4) Abrasion resistance

[0082] After weighing, the coating sample was subjected to a friction test with a load of 1000g and a rotation speed of 70r / min on an abrasion tester (model: JM-Ⅳ, Chengdu Chaoda Technology Co., Ltd.), and the mass difference before and after the test was recorded.

[0083] (5) Hydrophobic and oleophobic properties

[0084] The sliding ability of a material surface to oil is defined as dynamic oleophobicity. A contact angle meter (model: DSA-25) was used. The company measures the contact angle (CA) and advance angle (θ) of the coating. Adv ), receding angle (θ) Rec The dynamic contact angle (CAH) of the liquid gasoline was measured at a volume of 5 μL. The dynamic contact angle of the liquid was determined by averaging the values ​​measured at three different points on each sample surface.

[0085] CAH is defined as the difference between the advance angle and the retreat angle of the test droplet.

[0086] CAH = θ Adv -θ Rec

[0087] CAH indicates how easily a droplet slides on a rough surface. The smaller the CAH, the easier it is for the droplet to slide; the larger the CAH, the easier it is for the droplet to adhere to the surface.

[0088] Example 1

[0089] This embodiment illustrates the non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines and its preparation method according to the present invention.

[0090] (1) Preparation of polyurea prepolymer: 45 parts by weight of polypropylene glycol (PPG, analytical grade, M) were mixed. n=2000) was vacuum dehydrated at 95℃ for about 5 hours to reduce the water content to less than 0.05%. The dehydrated polypropylene glycol was then reacted with 55 parts by weight of 4,4-diphenylmethane diisocyanate (MDI, analytical grade) at 80℃ under nitrogen atmosphere. n =250) Incubate the reaction, and determine the NCO group content according to GB / T 12009.4. Stop the reaction when it reaches 15% to obtain polyurea prepolymer, i.e. component A, and store it under nitrogen.

[0091] (2) Preparation of amino compounds: 52 parts by weight of polyether polyamine T-5000 (analytical grade, M) were prepared. n =5000), 13 parts by weight of polyether polyamine D-2000 (analytical grade, M n =2000), 14 parts by weight of 3,5-diethyltoluenediamine (E100, analytical grade, M n =89), 21 parts by weight of 4,4-bis-sec-butylaminodiphenylmethane (W6200, analytical grade, M n =155), 10 parts by weight of polydimethylsiloxane (PDMS, analytical grade, M n =3000) and 2.2 parts by weight of defoamer BYK-085, 1.1 parts by weight of leveling agent BYK333, 1.1 parts by weight of coupling agent KH580, 2.2 parts by weight of dispersant poly(hydroxyethyl methacrylate) and 1.1 parts by weight of antioxidant 1088 were stirred evenly in a high-speed disperser and then vacuum dehydrated in a reaction vessel for 3 hours to reduce the moisture content to less than 0.05% to obtain component B, which was then stored under nitrogen.

[0092] (3) Coating Preparation: A coating was prepared by rapid spraying of the substrate using a Gusmer H20 / 35 high-pressure airless sprayer and a GX-7 spray gun. The A component (isocyanate polyurea prepolymer) obtained in step (1) and the B component (amine compound) obtained in step (2) were injected into the isocyanate compound storage tank and the amine compound storage tank, respectively. The mixture was heated to 80°C, the spray gun pressure was set to 17 MPa, and the volume ratio of A component to B component was set to 1:1.1. A polyurea coating of approximately 2 mm was formed on the steel plate. Acetone solvent was continuously sprayed onto the polyurea coating for 1 hour, and allowed to slowly evaporate at room temperature for 1 day. After the solvent evaporated, the coating was cured for 7 days at 230°C and 50% relative humidity to form the non-fluorinated oleophobic polyurea anti-corrosion coating of this invention.

[0093] Example 2

[0094] This embodiment illustrates the non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines and its preparation method according to the present invention.

[0095] (1) The preparation process of polyurea prepolymer is the same as that in Example 1.

[0096] (2) Preparation of amino compounds: 52 parts by weight of polyether polyamine T-5000 (analytical grade, M) were prepared. n =5000), 13 parts by weight of polyether polyamine D-2000 (analytical grade, M n =2000), 14 parts by weight of 3,5-diethyltoluenediamine (E100, analytical grade, M n =89), 21 parts by weight of 4,4-bis-sec-butylaminodiphenylmethane (W6200, analytical grade, M n =155), 30 parts by weight of polydimethylsiloxane (PDMS, analytical grade, M n =3000) and 2.2 parts by weight of defoamer BYK-085, 1.1 parts by weight of leveling agent BYK333, 1.1 parts by weight of coupling agent KH580, 2.2 parts by weight of dispersant poly(hydroxyethyl methacrylate) and 1.1 parts by weight of antioxidant 1088 were stirred evenly in a high-speed disperser and then vacuum dehydrated in a reaction vessel for 3 hours to reduce the moisture content to less than 0.05% to obtain component B, which was then stored under nitrogen.

[0097] (3) Coating Preparation: A coating was prepared by rapid spraying of the substrate using a Gusmer H20 / 35 high-pressure airless sprayer and a GX-7 spray gun. The A component (isocyanate polyurea prepolymer) obtained in step (1) and the B component (amine compound) obtained in step (2) were injected into the isocyanate compound storage tank and the amine compound storage tank, respectively. The mixture was heated to 80°C, the spray gun pressure was set to 17 MPa, and the volume ratio of A component to B component was set to 1:1.3. A polyurea coating of approximately 2 mm was formed on the steel plate. Acetone solvent was continuously sprayed onto the polyurea coating for 1 hour, and allowed to slowly evaporate at room temperature for 1 day. After the solvent evaporated, the coating was cured for 7 days at 230°C and 50% relative humidity to form the non-fluorinated oleophobic polyurea anti-corrosion coating of this invention.

[0098] Example 3

[0099] This embodiment illustrates the non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines and its preparation method according to the present invention.

[0100] (1) The preparation process of polyurea prepolymer is the same as that in Example 1.

[0101] (2) Preparation of amino compounds: 52 parts by weight of polyether polyamine T-5000 (analytical grade, M) were prepared. n =5000), 13 parts by weight of polyether polyamine D-2000 (analytical grade, M n =2000), 14 parts by weight of 3,5-diethyltoluenediamine (E100, analytical grade, M n =89), 21 parts by weight of 4,4-bis-sec-butylaminodiphenylmethane (W6200, analytical grade, Mn =155), 50 parts by weight of polydimethylsiloxane (PDMS, analytical grade, M n =3000) and 2.2 parts by weight of defoamer BYK-085, 1.1 parts by weight of leveling agent BYK333, 1.1 parts by weight of coupling agent KH580, 2.2 parts by weight of dispersant poly(hydroxyethyl methacrylate) and 1.1 parts by weight of antioxidant 1088 were stirred evenly in a high-speed disperser and then vacuum dehydrated in a reaction vessel for 3 hours to reduce the moisture content to less than 0.05% to obtain component B, which was then stored under nitrogen.

[0102] (3) Coating Preparation: A coating was prepared by rapid spraying of the substrate using a Gusmer H20 / 35 high-pressure airless sprayer and a GX-7 spray gun. The A component (isocyanate polyurea prepolymer) obtained in step (1) and the B component (amine compound) obtained in step (2) were injected into the isocyanate compound storage tank and the amine compound storage tank, respectively. The mixture was heated to 80°C, the spray gun pressure was set to 17 MPa, and the volume ratio of A component to B component was set to 1:1.5. A polyurea coating of approximately 2 mm was formed on the steel plate. Acetone solvent was continuously sprayed onto the polyurea coating for 1 hour, and allowed to slowly evaporate at room temperature for 1 day. After the solvent evaporated, the coating was cured at 230°C and 50% relative humidity for 7 days to form the non-fluorinated oleophobic polyurea anti-corrosion coating of this invention.

[0103] Example 4

[0104] This embodiment illustrates the non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines and its preparation method according to the present invention.

[0105] (1) The preparation process of polyurea prepolymer is the same as that in Example 1.

[0106] (2) Preparation of amino compounds: 52 parts by weight of polyether polyamine T-5000 (analytical grade, M) were prepared. n =5000), 13 parts by weight of polyether polyamine D-2000 (analytical grade, M n =2000), 14 parts by weight of 3,5-diethyltoluenediamine (E100, analytical grade, M n =89), 21 parts by weight of 4,4-bis-sec-butylaminodiphenylmethane (W6200, analytical grade, M n =155), 30 parts by weight of polydimethylsiloxane (PDMS, analytical grade, M n=3000) and 2.2 parts by weight of defoamer BYK-085, 1.1 parts by weight of leveling agent BYK333, 1.1 parts by weight of coupling agent KH580, 2.2 parts by weight of dispersant poly(hydroxyethyl methacrylate) and 1.1 parts by weight of antioxidant 1088 were stirred evenly in a high-speed disperser and then vacuum dehydrated in a reaction vessel for 3 hours to reduce the moisture content to less than 0.05% to obtain component B, which was then stored under nitrogen.

[0107] (3) Coating Preparation: A coating was prepared by rapid spraying of the substrate using a Gusmer H20 / 35 high-pressure airless sprayer and a GX-7 spray gun. The A component (isocyanate polyurea prepolymer) obtained in step (1) and the B component (amine compound) obtained in step (2) were injected into the isocyanate compound storage tank and the amine compound storage tank, respectively. The mixture was heated to 80°C, the spray gun pressure was set to 17 MPa, and the volume ratio of A component to B component was set to 1:1.3. A polyurea coating of approximately 2 mm was formed on the steel plate. Hexane solvent was continuously sprayed onto the polyurea coating for 1 hour, and allowed to slowly evaporate at room temperature for 1 day. After the solvent evaporated, the coating was cured for 7 days at 230°C and 50% relative humidity to form the non-fluorinated oleophobic polyurea anti-corrosion coating described in this invention.

[0108] Example 5

[0109] This embodiment illustrates the non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines and its preparation method according to the present invention.

[0110] (1) The preparation process of polyurea prepolymer is the same as that in Example 1.

[0111] (2) Preparation of amino compounds: 52 parts by weight of polyether polyamine T-5000 (analytical grade, M) were prepared. n =5000), 13 parts by weight of polyether polyamine D-2000 (analytical grade, M n =2000), 14 parts by weight of 3,5-diethyltoluenediamine (E100, analytical grade, M n =89), 21 parts by weight of 4,4-bis-sec-butylaminodiphenylmethane (W6200, analytical grade, M n =155), 30 parts by weight of polydimethylsiloxane (PDMS, analytical grade, M n =3000) and 2.2 parts by weight of defoamer BYK-085, 1.1 parts by weight of leveling agent BYK333, 1.1 parts by weight of coupling agent KH580, 2.2 parts by weight of dispersant poly(hydroxyethyl methacrylate) and 1.1 parts by weight of antioxidant 1088 were stirred evenly in a high-speed disperser and then vacuum dehydrated in a reaction vessel for 3 hours to reduce the moisture content to less than 0.05% to obtain component B, which was then stored under nitrogen.

[0112] (3) Coating Preparation: A coating was prepared by rapid spraying of the substrate using a Gusmer H20 / 35 high-pressure airless sprayer and a GX-7 spray gun. The A component (isocyanate polyurea prepolymer) obtained in step (1) and the B component (amine compound) obtained in step (2) were injected into the isocyanate compound storage tank and the amine compound storage tank, respectively. The mixture was heated to 80°C, the spray gun pressure was set to 17 MPa, and the volume ratio of A component to B component was set to 1:1.3. A polyurea coating of approximately 2 mm was formed on the steel plate. Toluene solvent was continuously sprayed onto the polyurea coating for 1 hour, and allowed to slowly evaporate at room temperature for 1 day. After the solvent evaporated, the coating was cured for 7 days at 230°C and 50% relative humidity to form the non-fluorinated oleophobic polyurea anti-corrosion coating of this invention.

[0113] Comparative Example 1

[0114] (1) The preparation process of polyurea prepolymer is the same as that in Example 1.

[0115] (2) Preparation of amino compounds: Unlike Example 1, polydimethylsiloxane was not added.

[0116] (3) Preparation of polyurea coating: A coating was prepared by rapid spraying of the substrate using a Gusmer H20 / 35 high-pressure airless sprayer and a GX-7 spray gun. The isocyanate polyurea prepolymer obtained in step (1) and the amino compound obtained in step (2) were injected into the isocyanate compound storage tank and the amine compound storage tank, respectively. The mixture was heated to 80°C, the spray gun pressure was set to 17 MPa, and the volume ratio of isocyanate polyurea prepolymer to amino compound was set to 1:1.1. A polyurea coating of approximately 2 mm was formed on the steel plate. Acetone solvent was continuously sprayed onto the polyurea coating for 1 hour, and allowed to evaporate slowly at room temperature for 1 day. After the solvent evaporated, the coating was cured at 230°C and 50% relative humidity for 7 days to form the polyurea coating.

[0117] Comparative Example 2

[0118] (1) The preparation process of polyurea prepolymer is the same as that in Example 1.

[0119] (2) The preparation process of the amino compound is the same as that in Example 1.

[0120] (3) Polyurea Coating Preparation: A rapid coating was prepared by spraying the substrate using a Gusmer H20 / 35 high-pressure airless sprayer and a GX-7 spray gun. The isocyanate polyurea prepolymer obtained in step (1) and the amino compound obtained in step (2) were injected into the isocyanate compound storage tank and the amine compound storage tank, respectively. The mixture was heated to 80°C, the spray gun pressure was set to 17 MPa, and the volume ratio of isocyanate polyurea prepolymer to amino compound was set to 1:1.1. A polyurea coating of approximately 2 mm was formed on the steel plate. The coating was then cured for 7 days at 230°C and 50% relative humidity to form the polyurea coating.

[0121] In the above examples and comparative examples, Examples 1-3 varied the mass fraction of PDMS, Examples 4-5 varied the type of weakly polar solvent, Comparative Example 1 did not add PDMS, and Comparative Example 2 did not undergo solvent evaporation. A schematic diagram of the contact angle of the non-fluorinated oleophobic polyurea anti-corrosion coating prepared in Example 2 is shown below. Figure 1 As shown. The infrared spectra of the coatings prepared in Comparative Example 1 and Example 2 are as follows. Figure 2 As shown, a is the infrared spectrum of the coating prepared in Comparative Example 1, and b is the infrared spectrum of the coating prepared in Example 2. The stress-strain curve of the non-fluorinated oleophobic polyurea anticorrosive coating prepared in Example 2 is shown below. Figure 3 As shown in Tables 1 and 2 below, the coating test results for each embodiment and comparative example are presented.

[0122] Table 1

[0123]

[0124]

[0125] Table 2

[0126]

[0127] As can be seen from the above examples and comparative examples, the addition of PDMS significantly improves the mechanical strength of the non-fluorinated oleophobic polyurea anti-corrosion coating. With increasing PDMS content, the adhesion, tensile strength, Shore hardness, and contact angle of the non-fluorinated oleophobic polyurea anti-corrosion coating all show an upward trend. This is because PDMS, being a flexible chain segment, enhances the toughness of the non-fluorinated oleophobic polyurea anti-corrosion coating. PDMS migration to the surface of the non-fluorinated oleophobic polyurea anti-corrosion coating also protects the coating, resulting in less mass wear. Furthermore, the low surface energy of PDMS also increases the oleophobicity of the non-fluorinated oleophobic polyurea anti-corrosion coating. With increasing PDMS content, the contact angle of the non-fluorinated oleophobic polyurea anti-corrosion coating increases, and the CAH decreases, enabling the coating to achieve a superoleophobic effect. The evaporation process of weakly polar solvents allows PDMS segments to migrate to the coating surface. Additionally, acetone solvent was found to be most effective, while hexane and toluene solvents evaporate more slowly, resulting in slower PDMS segment migration and thus affecting the oleophobic effect of the coating surface.

[0128] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines, characterized in that, The method includes: spraying component A and component B onto a substrate to form a polyurea coating, then continuously spraying a weakly polar solvent onto the polyurea coating, and then allowing the weakly polar solvent to evaporate, wherein component A is a polyurea prepolymer, and component B contains polyether polyamine, polydimethylsiloxane, chain extender, and additives; The weakly polar solvent is one or any combination of at least two of acetone, n-hexane, and toluene; The spraying amount of the weakly polar solvent is 0.4-1 g / cm³. 2 The continuous spraying time for weakly polar solvents is 0.5-3 hours; The method further includes preparing component A by prepolymerizing polyisocyanate and polyether polyol according to the following steps; In component B, relative to 100 parts by weight of the polyether polyamine, the content of the chain extender is 50-90 parts by weight, the content of the polydimethylsiloxane is 20-110 parts by weight, and the content of the additives is 10-50 parts by weight. The method further includes: after the weakly polar solvent has evaporated, curing it at 200-250℃ and relative humidity of 30-60% for 3-15 days.

2. The method according to claim 1, characterized in that, The volume ratio of component A to component B is 1:1-1.

8.

3. The method according to claim 2, characterized in that, The volume ratio of component A to component B is 1:1.1-1.

5.

4. The method according to claim 1 or 2, characterized in that, The thickness of the resulting polyurea coating is 1-4 mm.

5. The method according to claim 4, characterized in that, The resulting polyurea coating has a thickness of 1.8-2.5 mm.

6. The method according to claim 1, characterized in that, The prepolymerization reaction is carried out at a temperature of 70-90℃ for 1-5 hours.

7. The method according to claim 1 or 6, characterized in that, The total amount of the polyisocyanate and the polyether polyol is 100 parts by weight, the amount of the polyether polyol is 30-60 parts by weight, and the amount of the polyisocyanate is 40-70 parts by weight.

8. The method according to claim 1 or 6, characterized in that, The polyisocyanate is an aromatic diisocyanate.

9. The method according to claim 8, characterized in that, The polyisocyanate is one or any combination of two or more of 4,4-diphenylmethane diisocyanate, toluene diisocyanate, and 1,5-naphthalene diisocyanate.

10. The method according to claim 1 or 6, characterized in that, The polyether polyol is one or more of polypropylene glycol, polyethylene glycol, and polyglycerol.

11. The method according to claim 1, characterized in that, The polyether polyamine is one or any combination of two or more of polyoxyethylene diamine, polyoxypropylene diamine, and polytetramethylene ether diamine.

12. The method according to claim 1 or 11, characterized in that, The chain extender is an amine chain extender.

13. The method according to claim 12, characterized in that, The chain extender is one or more of the following: 3,5-diethyltoluenediamine, 4,4-bis-sec-butylaminodiphenylmethane, poly(1,4-butanediol)bis(4-aminobenzoate) and 3,3'-dimethyl-4,4'-diaminodicyclohexanemethane.

14. The method according to claim 1, characterized in that, The additives contain defoamers, leveling agents, coupling agents, dispersants, and antioxidants.

15. A non-fluorinated oleophobic polyurea anti-corrosion coating for petrochemical pipelines prepared by the method according to any one of claims 1-14.

16. A petrochemical pipeline, comprising a pipeline substrate and a coating formed on the surface of the pipeline substrate, characterized in that, The coating is a non-fluorinated oleophobic polyurea anti-corrosion coating prepared by the method according to any one of claims 1-14.

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