A corrosion-resistant composite film, pipe, and their preparation methods and applications

Abstract

The present invention provides a corrosion-resistant composite film, a pipe and their preparation methods and applications. The corrosion-resistant composite film at least comprises a corrosion-resistant base film, and the corrosion-resistant base film comprises the following raw material components in parts by weight: 65 to 75 parts by weight of PPS, 5 to 15 parts by weight of modified PPS, and 5 to 20 parts by weight of a reinforcing material. The corrosion-resistant composite film provided in this application has excellent mechanical properties and corrosion resistance, and the corrosion-resistant pipe provided in this application has a strong bonding ability with the film and good corrosion resistance.

Description

Technical Field

[0001] The present invention relates to the field of materials science, and particularly to a corrosion-resistant composite film, a pipe, and their preparation methods and applications. Background Art

[0002] Metal pipes are widely used in various industrial fields due to their high strength and good performance, such as the oil and gas industry, the aerospace industry, the shipbuilding industry, the power industry, and so on. However, when metal pipes are in a harsh environment, they are very likely to be corroded by chemical media, resulting in the thinning or even breakage of the pipes, and thus causing serious economic losses. For example, when metal pipes are used for crude oil transportation, since the crude oil contains corrosive chemical substances such as sulfides, acidic substances, and dissolved gases, the inside of the pipeline will be corroded.

[0003] The traditional method to solve pipeline corrosion is to coat anti-corrosion coatings inside and outside the metal pipeline. However, during the construction process of the coatings, it is difficult to control the coating thickness. If the process is improper or the coating is uneven, it is easy to cause the formed coating to be uneven, and thus it is easy to form corrosion points locally. At the same time, when using traditional composite methods such as bonding or welding to composite the anti-corrosion coating with the metal pipe, there will be problems such as poor interfacial bonding, insufficient adhesion, and low production efficiency. When protecting the inside of the metal pipe against corrosion, these problems are more obvious and prominent.

[0004] Therefore, in view of the problems existing in the prior art, it is very necessary to provide a new corrosion-resistant pipe with good corrosion resistance, a tightly combined corrosion-resistant coating with the pipe, a long service life, and a simple preparation process. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a corrosion-resistant composite film, a pipe, and their preparation methods and applications to solve the problems in the prior art.

[0006] To achieve the above object and other related objects, the present invention is obtained through the following technical solutions.

[0007] In the first aspect of the present invention, a corrosion-resistant composite film is provided. The corrosion-resistant composite film at least includes a corrosion-resistant base film, and the corrosion-resistant base film includes the following raw material components in parts by weight: 65-75 parts by weight of PPS, 5-15 parts by weight of modified PPS, and 5-20 parts by weight of a reinforcing material.

[0008] For example, the parts by weight of PPS can be 65-70, 70-75; the parts by weight of modified PPS can be 5-10, 10-15; the parts by weight of the reinforcing material can be 5-10, 10-15, 15-20.

[0009] Preferably, the reinforcing material includes one or more of glass fiber, carbon fiber, calcium carbonate, and barium sulfate.

[0010] Preferably, the number-average molecular weight of the PPS is 60,000 - 80,000, as measured by GPC.

[0011] Preferably, the monofilament diameter of the glass fiber is 5 - 20 μm, and the length is 5 - 10 μm.

[0012] Preferably, the diameter of the carbon fiber is 5 - 10 μm, and the length is 5 - 10 μm.

[0013] Preferably, the particle size of the calcium carbonate is 1 - 5 μm. For example, it can be 1 - 2 μm or 2 - 5 μm.

[0014] Preferably, the particle size of the barium sulfate is 1 - 5 μm. For example, it can be 1 - 2 μm or 2 - 5 μm.

[0015] Preferably, the reinforcing material includes any one of the combinations of glass fiber and calcium carbonate, glass fiber and barium sulfate, carbon fiber and calcium carbonate, and carbon fiber and barium sulfate. Glass fiber and carbon fiber have good mechanical properties and corrosion resistance. Therefore, doping glass fiber and carbon fiber can improve the mechanical properties such as the mechanical strength of the film and its corrosion resistance; at the same time, when compounded with calcium carbonate and barium sulfate, due to their poor solubility and the fact that barium sulfate also has good flame retardancy and heat resistance, it can not only further enhance the mechanical properties and corrosion resistance of the film, but also help reduce costs.

[0016] More preferably, the reinforcing material is a combination of glass fiber and calcium carbonate, and the weight ratio of glass fiber to calcium carbonate is 10 - 12:3 - 5.

[0017] Preferably, the modification includes sulfonating the PPS with concentrated sulfuric acid, and the sulfonation degree of the sulfonated PPS is 8 - 15%. For example, it can be 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%.

[0018] In this application, the content and sulfonation degree of the sulfonated PPS are very specific parameters. If the addition amount is too much or the sulfonation degree is too high, it will lead to an increase in the water solubility of the film and a decrease in the corrosion resistance; if the content of the sulfonated PPS is too little or the sulfonation degree is too low, when it is subsequently applied to the surface of the pipe, it will result in a low bonding force and poor adhesion between the film and the pipe, causing the film to be easily detached, which is not conducive to the corrosion resistance of the pipe.

[0019] Preferably, during the sulfonation modification, the volume ratio of concentrated sulfuric acid to PPS is 7-12:1; the time is 1-3 h; the temperature is 20-50 °C. More specifically, the concentration of the concentrated sulfuric acid is 98%. For example, the volume ratio of concentrated sulfuric acid to PPS can be 7-10:1, 10-12:1; for example, the sulfonation modification time can be 1-1.5 h, 1.5-3 h, 1.5-2 h; for example, the sulfonation modification temperature can be 20-25 °C, 25-40 °C, 35-50 °C. Preferably, after the sulfonation modification reaction is completed, the reaction solution containing the sulfonation product needs to be filtered, washed, and dried to obtain sulfonated modified PPS.

[0020] Preferably, the corrosion-resistant composite film further includes a nano-layer, and the nano-layer is compounded on the corrosion-resistant base film.

[0021] Preferably, based on the total weight of the raw materials of the corrosion-resistant base film, the nano-layer contains the following raw material components: 2-4 wt% of ZrO2, 1-3 wt% of SiO2, and 0.5-2 wt% of MMT. For example, ZrO2 can be 2 wt%, 3 wt%, 4 wt%; for example, SiO2 can be 1 wt%, 2 wt%, 3 wt%; for example, MMT can be 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%. By setting the nano-coating, the corrosion resistance of the corrosion-resistant composite film can be further enhanced, and at the same time, it is also beneficial to increase the mechanical properties of the corrosion-resistant composite film.

[0022] Preferably, the average particle size of the ZrO2 powder is 15 μm-60 μm. For example, the average particle size of the ZrO2 powder can be 15 μm-30 μm, 30 μm-60 μm.

[0023] Preferably, the average particle size of the SiO2 powder is 15 μm-60 μm. For example, the average particle size of the SiO2 powder can be 15 μm-40 μm, 40 μm-60 μm.

[0024] Preferably, the average particle size of the MMT powder is 5 μm-20 μm. For example, the average particle size of the MMT powder can be 5 μm-15 μm, 15 μm-20 μm. Preferably, the water absorption rate of the corrosion-resistant composite film is ≤0.5‰. For example, it can be 0.1‰, 0.2‰, 0.3‰.

[0025] Preferably, the tensile strength of the corrosion-resistant composite film is 50-100 MPa; the elongation at break is 5-10%. For example, the tensile strength can be 50-68 MPa, 62-100 MPa, 62-68 MPa; for example, the elongation at break can be 5-6.5%, 5.8-10%, 5.8-6.5%.

[0026] The second aspect of the present invention provides a method for preparing the corrosion-resistant composite film as described above. The specific steps are as follows: Mix the above-mentioned PPS, modified PPS and reinforcing material in proportion, and then conduct melt blending through a twin-screw extruder. After extrusion granulation, form a film by high-temperature casting to provide a corrosion-resistant base film.

[0027] Preferably, mix ZrO2, SiO2, and MMT evenly in proportion to obtain a mixture, and then compound the mixture on the surface of the corrosion-resistant base film to form a nano-layer, thereby obtaining the corrosion-resistant composite film. More specifically, when compounding the nano-layer, it can only be compounded on a single surface of the corrosion-resistant base film, and the corresponding surface of the other base film is not compounded with the nano-layer.

[0028] Preferably, the temperature of the melt blending is 280 - 320 °C. For example, the temperature can be 280 - 300 °C, 300 - 320 °C.

[0029] Preferably, the temperature of the high-temperature casting to form a film is 290 - 350 °C. For example, the temperature can be 290 - 310 °C, 310 - 350 °C.

[0030] Preferably, the above-mentioned compounding is carried out by plasma spraying.

[0031] Preferably, during plasma spraying, the spraying power is 20 - 80 kW, and the spraying distance is 80 - 150 mm. For example, the spraying power can be 20 - 40 kW, 35 - 40 kW, 35 - 80 kW; for example, the spraying distance can be 80 - 100 mm, 100 - 150 mm.

[0032] Preferably, during plasma spraying, the particle size of the spraying powder is 15 - 70 μm. For example, it can be 15 - 30 μm, 30 - 60 μm, 20 - 50 μm, 40 - 70 μm.

[0033] The third aspect of the present invention provides a corrosion-resistant pipe, and the inner wall of the pipe is completely compounded with the corrosion-resistant composite film as described above.

[0034] Preferably, the pipe is one or more of stainless steel pipes, titanium alloy pipes, and aluminum alloy pipes.

[0035] Preferably, the thickness of the corrosion-resistant composite film is 20 - 80 μm. For example, it can be 50 - 75 μm, 20 - 75 μm, 50 - 80 μm, 65 - 75 μm.

[0036] The fourth aspect of the present invention provides a method for preparing the corrosion-resistant pipe as described above, including providing a pipe, pre-treating the inner surface of the pipe; providing the corrosion-resistant composite film as described above, and completely and tightly fitting the corrosion-resistant composite film on the inner surface of the pipe; after high-temperature compounding, cooling to obtain the corrosion-resistant pipe.

[0037] Preferably, the pretreatment includes one or more of sandblasting, grinding, cleaning, pickling, and silane coupling agent treatment.

[0038] More preferably, the pretreatment includes cleaning, pickling, and silane coupling agent treatment.

[0039] Preferably, the cleaning treatment includes ultrasonic cleaning using one or more of anhydrous ethanol and deionized water.

[0040] Preferably, the pickling treatment is carried out using one or more of hydrochloric acid, sulfuric acid, dilute nitric acid, and hydrofluoric acid.

[0041] Preferably, during pickling, the concentration of the acid used is 2 - 7%, the temperature is 40 - 60 °C, and the pickling time is 5 - 10 min.

[0042] Preferably, during the silane coupling agent treatment, the silane coupling agent used is a silane coupling agent capable of reacting with sulfonic acid groups; the silane coupling agent contains one or more groups of epoxy groups, amino groups, and isocyanate groups.

[0043] Preferably, the silane coupling agent includes one or two of γ - aminopropyltriethoxysilane and γ - glycidoxypropyltrimethoxysilane.

[0044] Preferably, the concentration of the silane coupling agent is 2 - 5%, and the treatment time of the silane coupling agent is 20 - 40 min.

[0045] Preferably, the temperature of the high - temperature composite is 250 - 350 °C. More preferably, it is 280 - 350 °C. For example, it can be 300 - 320 °C, 280 - 320 °C, 300 - 350 °C.

[0046] Preferably, during the high - temperature composite, the inside of the pipe needs to be evacuated, and the vacuum degree inside the pipe is maintained at 50 - 100 kPa. For example, it can be 50 - 80 kPa, 80 - 100 kPa.

[0047] Preferably, the inside of the pipe is kept in a sealed state during evacuation.

[0048] More preferably, the sealed state of the inside of the pipe is ensured by setting detachable end caps at both ends of the pipe.

[0049] Preferably, an intermediate - frequency induction heating coil is used to provide the temperature required for the high - temperature composite. More preferably, the frequency of the intermediate - frequency induction heating coil is 500 - 2000 Hz.

[0050] The fifth aspect of the present invention provides an application of the corrosion - resistant pipe as described above in the oil and gas industry as a crude oil transportation pipeline.

[0051] Advantages of the present invention:

[0052] 1. The corrosion-resistant composite film provided by the present invention has excellent corrosion resistance, and can effectively protect metal pipes from corrosion in harsh environments, effectively extending the service life of the pipes.

[0053] 2. The preparation method of the corrosion-resistant pipe provided by the present invention avoids coating the inner wall of the pipe with paint, and instead directly attaches the formed film to the inner wall of the pipe, combined with a specific intermediate-frequency induction heating coil heating method, thus effectively avoiding the unevenness of the coating caused by processes such as spraying or spin coating, and avoiding the formation of local corrosion points.

[0054] At the same time, this preparation method can make the inner wall of the pipe and the corrosion-resistant composite film combine tightly, with strong adhesion, effectively avoiding the occurrence of situations such as coating blistering or peeling off in a short time.

[0055] 3. The corrosion-resistant pipe provided by the present invention has excellent corrosion resistance, can transport corrosive liquids for a long time, has a long service life, and at the same time has a simple process and low cost, and is very suitable for large-scale popularization and use. Description of the drawings

[0056] Figure 1 It shows a heating schematic diagram of the pipes in Examples 4 and 5 of the present invention when compounding the film.

[0057] Figure 1 Description of the component numbers

[0058] 1. Pipe

[0059] 2. Intermediate-frequency induction heating coil

[0060] 3. Head Detailed implementation manners

[0061] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0062] Before further describing the specific implementation manners of the present invention, it should be understood that the protection scope of the present invention is not limited to the following specific implementation manners; it should also be understood that the terms used in the embodiments of the present invention are for the purpose of describing specific implementation manners, rather than limiting the protection scope of the present invention. The test methods without specific conditions noted in the following embodiments are usually carried out under conventional conditions, or according to the conditions recommended by each manufacturer.

[0063] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any value therebetween can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art of this technology. In addition to the specific methods, equipment, and materials used in the embodiments, according to the knowledge of those skilled in the art of this technology and the description of the present invention, any methods, equipment, and materials of the prior art similar to or equivalent to those described in the embodiments of the present invention can also be used to implement the present invention.

[0064] The technical solution of this application provides a corrosion-resistant composite film and a preparation method thereof. By introducing a specific content of sulfonated modified PPS and combining with reinforcing materials and nano-coatings, the corrosion-resistant composite film not only has good mechanical properties but also excellent corrosion resistance and stability.

[0065] In addition, this application also provides a corrosion-resistant pipe and a preparation method thereof with excellent corrosion resistance and strong film coating adhesion. The preparation method of this application pretreats the surface of the pipe with a specific silane coupling agent capable of reacting with sulfonic acid groups, and at the same time combines the corrosion-resistant composite film with a specific content of sulfonic acid groups as described above, so that a chemical reaction can occur between the surface of the pipe and the corrosion-resistant composite film to form chemical bonds. On the basis of ensuring corrosion resistance, it also greatly improves the adhesion ability of the film on the surface of the pipe, thus avoiding the problem of uneven coating application in the prior art, and effectively solving the problems of weak interfacial bonding, insufficient adhesion, and low production efficiency when using traditional composite methods such as bonding or welding to composite the anti-corrosion film and the metal pipe. In addition, the high-temperature composite method used in this application is simple in operation and low in cost, which is conducive to large-scale popularization and application.

[0066] In the following embodiments of this application, the preparation method of the sulfonated modified PPS specifically includes the following steps:

[0067] 1) In an environment of 25°C, add PPS to concentrated sulfuric acid (the volume ratio of concentrated sulfuric acid to PPS is 10:1), and react for 1.5 h to obtain a reaction solution containing sulfonated modified PPS. The concentration of the concentrated sulfuric acid is 98%;

[0068] 2) After the reaction is completed, slowly pour the reaction solution in step 1) into a large amount of ice water to precipitate the sulfonated modified PPS, wash the sulfonated modified PPS until it is neutral, and then dry it to obtain the sulfonated modified PPS. The sulfonation degree of the sulfonated modified PPS is 12%.

[0069] In the following embodiments of the present application, the average monofilament diameter of the glass fiber used is 10 μm, and the length is 10 μm; the average diameter of the carbon fiber is 10 μm, and the length is 10 μm; the average particle size of calcium carbonate is 2 μm; the average particle size of barium sulfate is 2 μm; the average particle size of ZrO2 powder is 30 μm, the average particle size of SiO2 powder is 40 μm, and the average particle size of MMT is 15 μm.

[0070] In the following embodiments of the present application, when preparing the composite film with a nano-layer, the nano-layer is only compounded on a single surface of the film, and the corresponding other film surface is not compounded with the nano-layer; and when the composite film with a nano-layer is compounded on the pipe, the surface of the film without the nano-layer is completely and tightly attached to the inner surface of the pipe for compounding.

[0071] Example 1

[0072] This example provides a specific corrosion-resistant composite film and its preparation method. The specific steps are as follows:

[0073] 1) Preparation of the corrosion-resistant base film

[0074] Mix 70 parts by weight of PPS, 15 parts by weight of sulfonated modified PPS, 12 parts by weight of glass fiber, and 3 parts by weight of calcium carbonate using a high-speed blender for 1 h at a speed of 600 rpm to obtain a uniformly mixed blend. Then, put the above blend into a twin-screw extruder, melt-blend and extrude into pellets at 300 °C, and then melt and cast into a film at 310 °C to obtain the corrosion-resistant base film, the thickness of which is 50 μm.

[0075] 2) Preparation of the corrosion-resistant composite film

[0076] Based on the total mass of the raw materials of the corrosion-resistant base film in step 1), take 3 wt% ZrO2, 2 wt% SiO2, 1 wt% MMT, and add an appropriate amount of ethanol as a dispersant, and ball mill for 4 hours (rotation speed 300 rpm) to uniformly disperse, and after drying, sieve (sieve hole diameter is 50 μm) to obtain a composite powder.

[0077] Use a plasma spraying instrument to spray the corrosion-resistant base film obtained in step 1). Set the main gas of the plasma gas to argon, with a flow rate of 40 - 60 L / min, the auxiliary gas to hydrogen, with a flow rate of 5 - 10 L / min; the spraying power is 40 kW, the spraying distance is 100 mm, and the powder feeding rate is 10 g / min.

[0078] Obtain the corrosion-resistant composite film, and the thickness of the corrosion-resistant composite film is 65 μm.

[0079] Example 2

[0080] This embodiment provides a specific corrosion-resistant composite film and its preparation method. The specific steps are as follows:

[0081] 1) Preparation of the corrosion-resistant base film

[0082] Mix 65 parts by weight of PPS, 10 parts by weight of sulfonated modified PPS, 12 parts by weight of glass fiber, and 3 parts by weight of calcium carbonate using a high-speed mixer for 1 h at a rotation speed of 600 rpm to obtain a uniformly mixed blend. Then, put the above blend into a twin-screw extruder, melt-blend and extrude into pellets at 320 °C, and then melt-cast into a film at 310 °C to obtain the corrosion-resistant base film, the thickness of which is 60 μm.

[0083] 2) Preparation of the corrosion-resistant composite film

[0084] Based on the total mass of the raw materials of the corrosion-resistant base film in step 1), take 4 wt% ZrO2, 1 wt% SiO2, 0.5 wt% MMT, and add an appropriate amount of ethanol as a dispersant, and ball-mill for 4 hours (rotation speed 300 rpm) to uniformly disperse. After drying, sieve (sieve pore diameter is 50 μm) to obtain a composite powder.

[0085] Use a plasma spraying instrument to spray the corrosion-resistant base film obtained in step 1). Set the main gas of the plasma gas to argon with a flow rate of 40 - 60 L / min, the auxiliary gas to hydrogen with a flow rate of 5 - 10 L / min; the spraying power is 35 kW, the spraying distance is 100 mm, and the powder feeding rate is 10 g / min.

[0086] Obtain the corrosion-resistant composite film, and the thickness of the corrosion-resistant composite film is 75 μm.

[0087] Example 3

[0088] This embodiment provides a specific corrosion-resistant composite film and its preparation method. The specific steps are as follows:

[0089] 1) Preparation of the corrosion-resistant base film

[0090] Mix 75 parts by weight of PPS, 5 parts by weight of sulfonated modified PPS, 12 parts by weight of glass fiber, and 3 parts by weight of calcium carbonate using a high-speed mixer for 1 h at a rotation speed of 600 rpm to obtain a uniformly mixed blend. Then, put the above blend into a twin-screw extruder, melt-blend and extrude into pellets at 320 °C, and then melt-cast into a film at 310 °C to obtain the corrosion-resistant base film, the thickness of which is 50 μm.

[0091] 2) Preparation of the corrosion-resistant composite film

[0092] The same as in Example 2.

[0093] A corrosion-resistant composite film is obtained, and the thickness of the corrosion-resistant composite film is 65 μm.

[0094] Example 4

[0095] This example provides a specific corrosion-resistant pipe and its preparation method. The specific steps are as follows:

[0096] 1) Pretreat the pipe

[0097] 1-1) Immerse the 304 stainless steel pipe completely in absolute ethanol, ultrasonically clean for 10 min, and then wash with deionized water until the inner surface of the 304 stainless steel pipe is clean without impurities such as oil stains, and dry.

[0098] 1-2) Immerse the 304 stainless steel pipe obtained in 1-1) completely in hydrochloric acid (concentration 5%, temperature 50 °C), soak for 5 min, and then wash with deionized water until the 304 stainless steel pipe is neutral, and dry.

[0099] 1-3) Dissolve γ-aminopropyltriethoxysilane in an ethanol aqueous solution (volume ratio of absolute ethanol to water: 9:1), stir for 15 min, adjust the pH to 4 with acetic acid, and continue stirring until γ-aminopropyltriethoxysilane is fully hydrolyzed in the solution to obtain a silane mixed solution with a concentration of 2%.

[0100] 1-4) Immerse the 304 stainless steel pipe obtained in 1-2) completely in the silane mixed solution obtained in 1-3), ensure that the silane mixed solution fully covers the inner surface of the 304 stainless steel pipe, take it out after soaking for 30 min, and dry to complete the pretreatment of the inner surface of the 304 stainless steel pipe.

[0101] 2) Composite the corrosion-resistant composite film

[0102] Completely and tightly attach the corrosion-resistant composite film prepared in Example 1 to the inner surface of the pretreated 304 stainless steel pipe, and wrap a movable intermediate frequency induction heating coil (frequency 500 - 2000 Hz) on the outer surface of the 304 stainless steel pipe, and heat to 320 °C, move the intermediate frequency induction heating coil so that the entire pipe is in an environment of 320 °C.

[0103] At the same time, use a detachable head to seal the pipe so that the inside of the pipe is in a sealed state. Connect a detachable head at one end through a vacuum pump, evacuate the inside of the pipe until the vacuum degree is 80 kPa, keep warm and pressurize for 30 min, and then cool naturally to obtain the corrosion-resistant pipe.

[0104] Example 5

[0105] This embodiment provides a specific corrosion-resistant pipe and its preparation method. The specific steps are as follows:

[0106] 1) Pretreat the pipe

[0107] 1-1) The same as 1-1) of Example 4.

[0108] 1-2) The same as 1-2) of Example 4.

[0109] 1-3) Replace γ-aminopropyltriethoxysilane with γ-glycidoxypropyltrimethoxysilane, and the rest is the same as 1-2) of Example 3.

[0110] 1-4) Immerse the 304 stainless steel pipe obtained in 1-2) completely into the silane mixed solution obtained in 1-3), and the rest of the operations are the same as 1-3) of Example 4 to complete the pretreatment of the inner surface of the 304 stainless steel pipe.

[0111] 2) Composite corrosion-resistant composite film

[0112] Closely attach the corrosion-resistant composite film prepared in Example 1 to the inner surface of the pretreated 304 stainless steel pipe, and wrap a movable intermediate frequency induction heating coil (frequency 500~2000Hz) on the outer surface of the 304 stainless steel pipe, and heat to 300°C, move the intermediate frequency induction heating coil so that the entire pipe is in an environment of 300°C.

[0113] At the same time, use a detachable head to seal the pipe so that the inside of the pipe is in a sealed state. Connect a detachable head at one end through a vacuum pump to evacuate the inside of the pipe until the vacuum degree is 50 kPa. After maintaining the temperature and pressure for 30 minutes, cool naturally to obtain the corrosion-resistant pipe.

[0114] Example 6

[0115] This embodiment provides a specific corrosion-resistant pipe and its preparation method. The specific steps are as follows:

[0116] 1) Pretreat the pipe

[0117] Except for not performing pickling, the rest of the steps are the same as 1) of Example 4.

[0118] 2) Composite corrosion-resistant composite film

[0119] The same as 2) of Example 4.

[0120] Comparative Example 1

[0121] This comparative example provides a film.

[0122] Identical to Example 1, except that the raw materials for preparing the base film are replaced with: 70 parts by weight of PPS, 25 parts by weight of sulfonated modified PPS, 12 parts by weight of glass fiber, and 3 parts by weight of calcium carbonate, and the rest is the same.

[0123] Comparative Example 2

[0124] This comparative example provides a film.

[0125] Identical to Example 1, except that the raw materials for preparing the base film are replaced with: 70 parts by weight of PPS, 0 parts by weight of sulfonated modified PPS, 12 parts by weight of glass fiber, and 3 parts by weight of calcium carbonate, and the rest is the same.

[0126] Comparative Example 3

[0127] This comparative example provides a film.

[0128] Identical to Example 1, except that the raw materials for preparing the base film are replaced with: 70 parts by weight of PPS, 15 parts by weight of sulfonated modified PPS, and the rest is the same.

[0129] Comparative Example 4

[0130] This comparative example provides a film.

[0131] Only provide the corrosion-resistant base film prepared in step 1) of Example 1.

[0132] Comparative Example 5

[0133] This comparative example provides a pipe.

[0134] Without pre-treating the pipe, directly tightly attach the corrosion-resistant composite film prepared in Example 1 to the inner surface of the pre-treated 304 stainless steel pipe, and the rest is the same as Example 4.

[0135] Comparative Example 6

[0136] This comparative example provides a pipe.

[0137] Do not perform the silane coupling treatment in step 1-2) of Example 4, and the rest is the same as Example 4.

[0138] Comparative Example 7

[0139] This comparative example provides a pipe.

[0140] Replace the silane coupling treatment in step 1-2) of Example 4 with pickling treatment, specifically: completely immerse the 304 stainless steel pipe without oil and impurities after cleaning in hydrochloric acid (concentration 5%, temperature 50°C), after soaking for 5 minutes, wash with deionized water until the titanium alloy pipe is neutral, and dry, and the rest is the same as Example 4.

[0141] Comparative Example 8

[0142] This comparative example provides a kind of pipe.

[0143] It is the same as Example 4, except that in step 1-2), γ-aminopropyltriethoxysilane is replaced by vinyltrimethoxysilane (silane coupling agent A171), and the other steps are the same.

[0144] Comparative Example 9

[0145] This comparative example provides a kind of pipe.

[0146] Replace the corrosion-resistant composite film used in Example 4 with the corrosion-resistant composite film prepared in Comparative Example 2, and the rest is the same as Example 4.

[0147] Comparative Example 10

[0148] Replace the corrosion-resistant composite film used in Example 4 with the corrosion-resistant composite film prepared in Comparative Example 3, and the rest is the same as Example 4.

[0149] Comparative Example 11

[0150] Replace the corrosion-resistant composite film used in Example 4 with the corrosion-resistant composite film prepared in Comparative Example 4, and the rest is the same as Example 4.

[0151] The applicant carried out performance tests on the films prepared in Examples 1-3 and Comparative Examples 1-4, including tensile strength test, elongation at break test, water absorption test and salt spray test.

[0152] The specific test methods are as follows:

[0153] The test method for tensile strength is carried out with reference to GB / T 1040.3-2006.

[0154] The test method for elongation at break is carried out with reference to GB / T 1040.3-2006.

[0155] The test method for water absorption is carried out with reference to GB / T 1034-2008.

[0156] The test method for salt spray experiment is carried out with reference to GB / T 10125-2021, in which acetic acid salt spray test (AASS) is used: 5% sodium chloride acidic solution with glacial acetic acid added is atomized for testing, and the cyclic spraying method is adopted until the corrosion phenomenon appears on the material to be tested. The time in Table 1 below is the time when corrosion appears in the salt spray test.

[0157] The specific results are shown in Table 1 below.

[0158] Table 1

[0159]

[0160] As can be seen from Table 1, during the acetic acid salt spray test, the films in Examples 1 to 3 did not show corrosion phenomena for at least 1500 hours; while the films in Comparative Example 1 and Comparative Example 4 showed spot-like or cloud-like discoloration on the surface after 300 hours and 700 hours respectively, and local bubbles appeared, that is, corrosion phenomena occurred; the film in Comparative Example 3 showed spot-like or cloud-like discoloration on the surface after 900 hours, that is, corrosion phenomena occurred, indicating that the films in Examples 1 to 3 have good corrosion resistance. It can also be seen from Table 1 that the tensile strength of the films in Examples 1 to 3 is 62 to 68 MPa, the elongation at break is 5.8 to 6.5%, and the water absorption rate is 0.1 to 0.3‰, indicating that their mechanical properties are good and the water absorption rate is low.

[0161] Moreover, it can be known from Examples 1 to 3 and Comparative Example 1 that the films prepared with too high a content of sulfonated modified PPS have poor mechanical properties, high water absorption rate, and poor corrosion resistance, not meeting the application requirements; it shows that in the present invention, the content of sulfonated modified PPS is a very important parameter limitation. If the content of sulfonated modified PPS is too high and exceeds the limited range of this application, the corrosion resistance of the film will be greatly reduced, which may be determined by the hydrophilicity of sulfonated modified PPS; it can be known from Examples 1 to 3 and Comparative Example 3 that when no reinforcing material is added, the mechanical properties of the film decrease and have a certain impact on the corrosion resistance; it can be known from Examples 1 to 3 and Comparative Example 4 that the setting of the nano-coating can increase the mechanical properties and corrosion resistance of the film to a certain extent.

[0162] In summary, the corrosion-resistant composite film provided by the present invention has good mechanical properties, excellent flexibility and mechanical stability. At the same time, the corrosion-resistant composite film provided by the present invention has an extremely low water absorption rate, indicating that it has good stability in complex application environments and excellent corrosion resistance.

[0163] The applicant also tested the performance of the pipes prepared in Examples 4 to 5 and Comparative Examples 5 to 11, including salt spray tests and adhesion tests.

[0164] The specific test methods are as follows:

[0165] The test method of the salt spray experiment refers to GB / T 10125-2021. Among them, the acetic acid salt spray test (AASS) is used: a 5% sodium chloride acidic solution containing glacial acetic acid is atomized for testing, and the cyclic spraying method is adopted until the corrosion phenomenon appears on the material to be tested. The time in Table 2 below is the time when corrosion appears in the salt spray test.

[0166] The test method for the adhesion experiment was carried out with reference to GB / T 5210-2006.

[0167] The specific results are shown in Table 2 below.

[0168] Table 2

[0169] Remarks Salt spray test (h) Adhesion test (MPa) Example 4 Greater than 1500 3.2 Example 5 Greater than 1500 3.0 Example 6 1300 2.7 Comparative example 5 The pipe was not pretreated 500 1.5 Comparative example 6 The pipe pretreatment only included cleaning 550 1.8 Comparative example 7 The pipe pretreatment included cleaning and pickling 630 2.1 Comparative example 8 Replace with other coupling agents 560 1.8 Comparative example 9 Use the film without modified PPS in Comparative example 2 550 1.6 Comparative example 10 Use the film without reinforcing material in Comparative example 3 900 2.8 Comparative example 11 Use the film without nano - coating in Comparative example 4 700 3.0

[0170] When the same salt spray experiment test was carried out only with 304 stainless steel pipes, it was found that slight white rust or pitting corrosion occurred on the 304 stainless steel pipes at 60 hours.

[0171] As can be seen from Examples 4 to 6 in Table 2, the corrosion-resistant pipes provided by the invention have excellent corrosion resistance. During the acetic acid salt spray test, they can maintain for at least 1300 hours without corrosion; and the adhesion of the film on the surface of the pipes is strong, and the drawing strength can reach 2.7 to 3.2.

[0172] As can be seen from Example 4 and Comparative Examples 5 to 6 in Table 2, local bubbles and local peeling of the film occurred on the pipes in Comparative Examples 5 to 6 at 500 and 550 hours respectively. This shows that the pretreatment of the pipes is a very important technical means. If the pipes are not pretreated or only cleaned, the adhesion ability of the film on the surface of the pipes is weak and easy to peel off, resulting in poor corrosion resistance of the pipes.

[0173] As can be seen from Example 4 and Comparative Example 7 in Table 2, local bubbles and local peeling of the film occurred on the pipe in Comparative Example 7 at 630 hours. This shows that the pretreatment of silane coupling for the pipes in this application is very important. If only pickling pretreatment is carried out on the pipes, the adhesion of the film on the surface of the pipes cannot be increased well, and at the same time, the corrosion resistance of the pipes is poor.

[0174] As can be seen from Example 4 and Comparative Example 8 in Table 2, local bubbles and local peeling of the film occurred on the pipe in Comparative Example 8 at 560 hours. This shows that in this application, the selection of the silane coupling agent is also very specific. If other coupling agents that cannot react with sulfonic acid groups are used, the adhesion ability of the film on the surface of the pipes is weak and easy to peel off, and the corrosion resistance of the pipes is poor.

[0175] As can be seen from Example 4 and Comparative Example 9 in Table 2, local bubbles and local peeling of the film occurred on the pipe in Comparative Example 9 at 550 hours. This shows that in this application, the content of sulfonated modified PPS is a very important parameter limit. If the content of sulfonated modified PPS is too low or not added, the adhesion ability of the film on the surface of the pipes is weak, and the corrosion resistance of the pipes is poor.

[0176] As can be seen from Example 4 and Comparative Examples 10-11 in Table 2, the pipes in Comparative Examples 10-11 showed spotted or cloudy discoloration after 900 and 700 hours respectively, and there were local bubbles in the film. This indicates that if a film without a reinforcing material or a nano-coating is used as the coating of the pipe, the corrosion resistance of the pipe is poor compared with Examples 4 and 5.

[0177] In summary, the film coating in the corrosion-resistant pipe provided by the present invention has a strong bonding ability with the metal pipe, good adhesion of the film, and excellent corrosion resistance of the pipe.

[0178] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A corrosion-resistant composite film, characterized in that, The corrosion-resistant composite film at least comprises a corrosion-resistant base film, and the corrosion-resistant base film comprises the following raw material components in parts by weight: 65-75 parts by weight of PPS, 5-15 parts by weight of sulfonated modified PPS, and 5-20 parts by weight of reinforcing material; The sulfonation modification is carried out with concentrated sulfuric acid, and the sulfonation degree of the sulfonated modified PPS is 8-15%; The corrosion-resistant composite film further comprises a nano-layer, and the nano-layer is compounded on the corrosion-resistant base film; Based on the total weight of the raw materials of the corrosion-resistant base film, the nano-layer comprises the following raw material components in content: 2-4 wt% of ZrO2, 1-3 wt% of SiO2, and 0.5-2 wt% of MMT.

2. The corrosion-resistant composite film according to claim 1, characterized in that, The reinforcing material comprises one or more of glass fiber, carbon fiber, calcium carbonate and barium sulfate.

3. The corrosion-resistant composite film according to claim 2, wherein, The single filament diameter of the glass fiber is 5-20 μm, and the length is 5-10 μm; And / or, the diameter of the carbon fiber is 5-10 μm, and the length is 5-10 μm; And / or, the particle size of the calcium carbonate is 1-5 μm; And / or, the particle size of the barium sulfate is 1-5 μm; And / or, during the sulfonation modification, the volume ratio of concentrated sulfuric acid to PPS is 7-12:1; the time is 1-3 h; the temperature is 20-50 °C; And / or, the water absorption rate of the corrosion-resistant composite film is ≤0.5‰; And / or, the tensile strength of the corrosion-resistant composite film is 50-100 MPa; the elongation at break is 5-10%.

4. A method for preparing a corrosion-resistant composite film according to any one of claims 1 to 3, characterized in that, The specific steps are as follows: After mixing the above-mentioned PPS, sulfonated modified PPS and reinforcing material in proportion, melt-blend them through a twin-screw extruder, and extrude and granulate them, and then cast a film at a high temperature to provide a corrosion-resistant base film; Mix ZrO2, SiO2 and MMT evenly in proportion to obtain a mixture, and compound the mixture on the surface of the corrosion-resistant base film to form a nano-layer, so as to obtain a corrosion-resistant composite film; the compounding is carried out by means of plasma spraying.

5. The preparation method according to claim 4, characterized in that, The temperature of the melt-blending is 280-320 °C; And / or, the temperature of the high-temperature casting film is 290-350 °C.

6. A corrosion-resistant pipe, characterized in that, The inner wall of the pipe is completely compounded with the corrosion-resistant composite film as described in any one of claims 1-3; the thickness of the corrosion-resistant composite film is 20-80 μm.

7. A method for preparing the corrosion-resistant pipe as claimed in claim 6, characterized in that, Provide a pipe, and pre-treat the inner surface of the pipe; provide the corrosion-resistant composite film as described in any one of claims 1-3, and completely and tightly attach the corrosion-resistant composite film to the inner surface of the pipe; after high-temperature compounding, cool to obtain the corrosion-resistant pipe.

8. The preparation method according to claim 7, characterized in that, The pre-treatment includes one or more of sandblasting treatment, grinding treatment, cleaning treatment, pickling treatment, and silane coupling agent treatment; And / or, the temperature of the high-temperature compounding is 250-350 °C; And / or, during the high-temperature compounding, it is also necessary to evacuate the inside of the pipe, and keep the vacuum degree inside the pipe at 50-100 kPa; And / or, use an intermediate frequency induction heating coil to provide the temperature required for high-temperature compounding.

9. The preparation method according to claim 8, wherein Use one or more of hydrochloric acid, sulfuric acid, dilute nitric acid or hydrofluoric acid for the pickling treatment; And / or, when treated with a silane coupling agent, the silane coupling agent used contains one or more groups among epoxy groups, amino groups, and isocyanate groups; And / or, the frequency of the intermediate-frequency induction heating coil is 500 - 2000 Hz.

10. Application of a corrosion-resistant pipe as described in claim 6 or a corrosion-resistant pipe prepared by the preparation method according to any one of claims 7 - 9 in the petroleum industry as a crude oil transportation pipeline.

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