Corrosion-resistant composite film, pipe as well as preparation method and application of corrosion-resistant composite film

Abstract

The invention provides a corrosion-resistant composite film, a pipe as well as a preparation method and application of the corrosion-resistant composite film, 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 of PPS, 5-15 parts of modified PPS and 5-20 parts of a reinforcing material. The corrosion-resistant composite film provided by the invention is excellent in mechanical property and corrosion resistance, and the corrosion-resistant pipe provided by the invention is high in combining capacity with the film and good in corrosion resistance.

Description

Technical Field

[0001] The invention relates to the field of material science, and in particular to a corrosion-resistant composite film, a pipe, and a preparation method and application thereof. 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, aerospace industry, shipbuilding industry, power industry, etc. However, when metal pipes are in harsh environments, they are easily corroded by chemical media, causing the pipes to become thinner or even damaged, which in turn causes serious economic losses. For example, when metal pipes are used for crude oil transportation, crude oil contains corrosive chemicals such as sulfides, acidic substances, and dissolved gases, which will corrode the inside of the pipeline.

[0003] The traditional method to solve pipeline corrosion is to apply anti-corrosion coatings inside and outside metal pipelines. However, during the construction process, the coating thickness is difficult to control. If the process is improper or the coating is uneven, it is easy to cause uneven coatings, which in turn easily form corrosion points locally. At the same time, when using traditional composite methods such as bonding or welding to composite anti-corrosion coatings with metal pipes, there will be problems such as weak interface bonding, insufficient adhesion, and low production efficiency. When the inside of the metal pipe is protected from corrosion, the above problems are more 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, and the corrosion-resistant coating is tightly combined with the pipe, has a long service life, and a simple preparation process. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a corrosion-resistant composite film, a pipe and a preparation method and application thereof, so as to solve the problems in the prior art.

[0006] To achieve the above objectives and other related objectives, the present invention is achieved through the following technical solutions.

[0007] A first aspect of the present invention provides a corrosion-resistant composite film, which comprises at least 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 reinforcing material.

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

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

[0010] Preferably, the number average molecular weight of the PPS is 6w-8w, which is obtained by GPC testing.

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

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

[0013] Preferably, the particle size of the calcium carbonate is 1-5 μm, such as 1-2 μm, 2-5 μm.

[0014] Preferably, the particle size of the barium sulfate is 1-5 μm, such as 1-2 μm or 2-5 μm.

[0015] Preferably, the reinforcing material includes any one of a combination of glass fiber and calcium carbonate, a combination of glass fiber and barium sulfate, a combination of carbon fiber and calcium carbonate, and a combination of carbon fiber and barium sulfate. Glass fiber and carbon fiber have good mechanical properties and corrosion resistance, so doping with glass fiber and carbon fiber can improve the mechanical properties such as mechanical strength and corrosion resistance of the film; at the same time, compounding with calcium carbonate and barium sulfate, due to its poor solubility, and barium sulfate also has good flame retardancy and temperature 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%, such as 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%.

[0018] In the present application, the content and degree of sulfonation of the sulfonated modified PPS are very specific parameters. If the added amount is too much or the sulfonation degree is too high, the water solubility of the film will increase and the corrosion resistance will decrease; if the content of the sulfonated modified PPS is too little or the sulfonation degree is too low, when it is subsequently applied to the surface of the pipe, it will lead to low bonding strength and poor adhesion between the film and the pipe, causing the film to fall off easily, which is not conducive to the corrosion resistance of the pipe.

[0019] Preferably, during sulfonation modification, the volume ratio of concentrated sulfuric acid to PPS is 7-12:1; the time is 1-3h; and 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; the time for sulfonation modification can be 1-1.5h, 1.5-3h, 1.5-2h; the temperature for sulfonation modification 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 the sulfonated PPS.

[0020] Preferably, the corrosion-resistant composite film further comprises a nanolayer, and the nanolayer is composited on the corrosion-resistant base film.

[0021] Preferably, based on the total weight of the corrosion-resistant base film raw material, the nanolayer contains the following raw material components: 2-4wt% ZrO2, 1-3wt% SiO2 and 0.5-2wt% MMT. For example, ZrO2 can be 2wt%, 3wt%, 4wt%; SiO2 can be 1wt%, 2wt%, 3wt%; MMT can be 0.5wt%, 1wt%, 1.5wt%, 2wt%. The provision of the nanocoating can further enhance the corrosion resistance of the corrosion-resistant composite film, and 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 to 60 μm. For example, the average particle size of the ZrO2 powder may be 15 μm to 30 μm, or 30 μm to 60 μm.

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

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

[0025] Preferably, the tensile strength of the corrosion-resistant composite film is 50-100 MPa, and the elongation at break is 5-10%. For example, the tensile strength may be 50-68 MPa, 62-100 MPa, 62-68 MPa, and the elongation at break may 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, and the specific steps are: after mixing the above-mentioned PPS, modified PPS and reinforcing material in proportion, melt blending through a twin-screw extruder, extrusion granulation and high-temperature cast film formation to provide a corrosion-resistant base film.

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

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

[0029] Preferably, the temperature of the high-temperature casting film is 290-350° C. For example, the temperature may be 290-310° C. or 310-350° C.

[0030] Preferably, the composite is performed 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 may be 20-40 kW, 35-40 kW, 35-80 kW; and the spraying distance may be 80-100 mm, 100-150 mm.

[0032] Preferably, during plasma spraying, the particle size of the sprayed powder is 15-70 μm, such as 15-30 μm, 30-60 μm, 20-50 μm, or 40-70 μm.

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

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

[0035] Preferably, the thickness of the corrosion-resistant composite film is 20-80 μm, such as 50-75 μm, 20-75 μm, 50-80 μm, or 65-75 μm.

[0036] The fourth aspect of the present invention provides a method for preparing the corrosion-resistant pipe as described above, providing a pipe and pretreating 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 to the inner surface of the pipe; after high-temperature composite, cooling, and obtaining 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 treatment, pickling treatment and silane coupling agent treatment.

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

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

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

[0042] Preferably, when the silane coupling agent is used for the treatment, the silane coupling agent used is a silane coupling agent that can react with the sulfonic acid group; the silane coupling agent contains one or more groups selected from the group consisting of epoxy group, amino group and isocyanate group.

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

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

[0045] Preferably, the temperature of high temperature compounding is 250-350°C, more preferably 280-350°C, such as 300-320°C, 280-320°C, or 300-350°C.

[0046] Preferably, during high-temperature compounding, the tube needs to be evacuated to maintain a vacuum degree of 50-100 kPa, such as 50-80 kPa or 80-100 kPa.

[0047] Preferably, the tube is kept in a sealed state during vacuuming.

[0048] More preferably, detachable sealing heads are provided at the pipe openings at both ends to ensure that the inside of the pipe is in a sealed state.

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

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

[0051] Beneficial effects of the present invention: 1. The corrosion-resistant composite film provided by the present invention has excellent corrosion resistance, can effectively protect metal pipes from corrosion in harsh environments, and effectively extend the life of the pipes; 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 chooses to directly attach the formed film to the inner wall of the pipe, and combines it with a specific medium-frequency induction heating coil heating method, thereby effectively avoiding the uneven coating caused by processes such as spraying or spin coating, and avoiding the formation of local corrosion points; At the same time, the preparation method can make the inner wall of the pipe and the corrosion-resistant composite film closely bonded, with strong adhesion, effectively avoiding the occurrence of blistering or shedding of the coating in a short time; 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 has a simple process and low cost, and is very suitable for large-scale promotion and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram showing the heating of the tubes in Examples 4 and 5 of the present invention when they are laminated with thin films.

[0053] Figure 1 Component number description 1. Pipes; 2. Medium frequency induction heating coil; 3. End cap. DETAILED DESCRIPTION

[0054] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0055] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods in the following examples without specifying specific conditions are generally carried out under conventional conditions or under conditions recommended by the manufacturers.

[0056] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to realize the present invention.

[0057] The technical solution of the present application provides a corrosion-resistant composite film and a preparation method thereof. The corrosion-resistant composite film introduces a specific content of sulfonated modified PPS, and is combined with reinforcing materials and nano-coatings, so that the corrosion-resistant composite film not only has good mechanical properties but also has excellent corrosion resistance and stability.

[0058] In addition, the present application also provides a corrosion-resistant pipe with excellent corrosion resistance and strong film coating adhesion and a preparation method thereof. The preparation method of the present application pre-treats the surface of the pipe with a specific silane coupling agent that can react with sulfonic acid groups, and combines the corrosion-resistant composite film with a specific content of sulfonic acid groups as described above, so that the surface of the pipe can react chemically with the corrosion-resistant composite film to form a chemical bond. On the basis of ensuring corrosion resistance, the adhesion ability of the film on the surface of the pipe is greatly improved, thereby avoiding the problem of uneven coating in the prior art, and effectively solving the problems of weak interface bonding, insufficient adhesion, and low production efficiency when the traditional composite method such as bonding or welding is used to composite the anti-corrosion film with the metal pipe. In addition, the high-temperature composite method used in the present application is simple to operate and low in cost, which is conducive to large-scale promotion and application.

[0059] In the following embodiments of the present application, the preparation method of sulfonated modified PPS specifically includes the following steps: 1) PPS was added to concentrated sulfuric acid (the volume ratio of concentrated sulfuric acid to PPS was 10:1) at 25°C, and the reaction was carried out for 1.5 hours to obtain a reaction solution containing sulfonated PPS, wherein the concentration of the concentrated sulfuric acid was 98%; 2) After the reaction is completed, the reaction solution in step 1) is slowly poured into a large amount of ice water to precipitate the sulfonated modified PPS, and the sulfonated modified PPS is washed until it is neutral, and then dried to obtain the sulfonated modified PPS, wherein the sulfonation degree of the sulfonated modified PPS is 12%.

[0060] 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.

[0061] In the following embodiments of the present application, when preparing a composite film with a nanolayer, the nanolayer is only composited on a single surface of the film, and the other corresponding surface of the film is not composited with the nanolayer; and when the composite film with a nanolayer is composited on a pipe, one surface of the film without the nanolayer is completely and tightly fitted to the inner surface of the pipe for composite.

[0062] Example 1 This embodiment provides a specific corrosion-resistant composite film and a preparation method thereof, which specifically comprises the following steps: 1) Preparation of corrosion-resistant base film 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 were mixed in a high-speed blender for 1 hour at a speed of 600 rpm to obtain a uniformly mixed blend. The blend was then put into a twin-screw extruder, melt-blended and extruded at 300° C. to form granules, and then melted and cast at 310° C. to obtain the corrosion-resistant base film, which had a thickness of 50 μm.

[0063] 2) Preparation of corrosion-resistant composite films Based on the total mass of the raw materials of the corrosion-resistant base film in step 1), 3wt% ZrO2, 2wt% SiO2, and 1wt% MMT were taken, and an appropriate amount of ethanol was added as a dispersant. Ball milling was performed for 4 hours (rotation speed 300 rpm) to uniformly disperse the mixture. After drying, the mixture was sieved (the sieve particle size was 50μm) to obtain a composite powder.

[0064] The corrosion-resistant base film obtained in step 1) is sprayed with a plasma spraying apparatus, and the main gas of the plasma gas is set to argon with a flow rate of 40-60 L / min, and the auxiliary gas is set 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.

[0065] A corrosion-resistant composite film is obtained, and the thickness of the corrosion-resistant composite film is 65 μm.

[0066] Example 2 This embodiment provides a specific corrosion-resistant composite film and a preparation method thereof, which specifically comprises the following steps: 1) Preparation of corrosion-resistant base film 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 were mixed in a high-speed blender for 1 hour at a speed of 600 rpm to obtain a uniformly mixed blend. The blend was then put into a twin-screw extruder, melt-blended and extruded at 320° C. to form granules, and then melted and cast at 310° C. to obtain the corrosion-resistant base film, which had a thickness of 60 μm.

[0067] 2) Preparation of corrosion-resistant composite films Based on the total mass of the raw materials of the corrosion-resistant base film in step 1), 4wt% ZrO2, 1wt% SiO2, and 0.5wt% MMT were taken, and an appropriate amount of ethanol was added as a dispersant. Ball milling was performed for 4 hours (rotation speed 300 rpm) to uniformly disperse the mixture. After drying, the mixture was sieved (the sieve particle size was 50μm) to obtain a composite powder.

[0068] The corrosion-resistant base film obtained in step 1) is sprayed with a plasma spraying apparatus, and the main gas of the plasma gas is set to argon with a flow rate of 40-60 L / min, and the auxiliary gas is set 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.

[0069] A corrosion-resistant composite film is obtained, and the thickness of the corrosion-resistant composite film is 75 μm.

[0070] Example 3 This embodiment provides a specific corrosion-resistant composite film and a preparation method thereof, which specifically comprises the following steps: 1) Preparation of corrosion-resistant base film 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 were mixed in a high-speed blender for 1 hour at a speed of 600 rpm to obtain a uniformly mixed blend. The blend was then put into a twin-screw extruder, melt-blended and extruded into granules at 320° C., and then melted and cast into a film at 310° C. to obtain the corrosion-resistant base film of the film, with a thickness of 50 μm.

[0071] 2) Preparation of corrosion-resistant composite films Exactly the same as Example 2.

[0072] A corrosion-resistant composite film is obtained, and the thickness of the corrosion-resistant composite film is 65 μm.

[0073] Example 4 This embodiment provides a specific corrosion-resistant pipe and a preparation method thereof, which specifically includes the following steps: 1) Pretreatment of pipes 1-1) Immerse the 304 stainless steel pipe completely in anhydrous ethanol, ultrasonically clean it for 10 minutes, then clean it with deionized water until the inner surface of the 304 stainless steel pipe is clean and free of oil and other impurities, and then dry it.

[0074] 1-2) The 304 stainless steel pipe obtained in 1-1) is completely immersed in hydrochloric acid (concentration of 5%, temperature of 50°C) for 5 minutes, then washed with deionized water until the 304 stainless steel pipe is neutral, and dried.

[0075] 1-3) Dissolve γ-aminopropyltriethoxysilane in an ethanol-water solution (the volume ratio of anhydrous ethanol to water is 9:1), stir for 15 minutes, 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%.

[0076] 1-4) The 304 stainless steel pipe obtained in 1-2) is completely immersed in the silane mixed solution obtained in 1-3) to ensure that the silane mixed solution fully covers the inner surface of the 304 stainless steel pipe. After soaking for 30 minutes, take it out and dry it to complete the pretreatment of the inner surface of the 304 stainless steel pipe.

[0077] 2) Composite corrosion-resistant composite film The corrosion-resistant composite film prepared in Example 1 was completely and tightly attached to the inner surface of the pretreated 304 stainless steel pipe, and a movable medium-frequency induction heating coil (frequency 500-2000 Hz) was arranged on the outer surface of the 304 stainless steel pipe and heated to 320°C. The medium-frequency induction heating coil was moved so that all the pipes were in an environment of 320°C.

[0078] At the same time, a detachable head is used to seal the pipe so that the inside of the pipe is in a sealed state. A detachable head is connected through a vacuum pump to evacuate the inside of the pipe until the vacuum degree reaches 80 kPa. After keeping the temperature and pressure for 30 minutes, it is naturally cooled to obtain the corrosion-resistant pipe.

[0079] Example 5 This embodiment provides a specific corrosion-resistant pipe and a preparation method thereof, which specifically includes the following steps: 1) Pretreatment of pipes 1-1) is the same as 1-1) of Example 4.

[0080] 1-2) is the same as 1-2) of Example 4.

[0081] 1-3) except that γ-glycidyloxypropyltrimethoxysilane was used to replace γ-aminopropyltriethoxysilane, and the rest was the same as 1-2) of Example 3.

[0082] 1-4) The 304 stainless steel pipe obtained in 1-2) is completely immersed in the silane mixed solution obtained in 1-3), and the remaining operations are the same as 1-3) of Example 4 to complete the pretreatment of the inner surface of the 304 stainless steel pipe.

[0083] 2) Composite corrosion-resistant composite film The corrosion-resistant composite film prepared in Example 1 was tightly attached to the inner surface of the pretreated 304 stainless steel pipe, and a movable medium-frequency induction heating coil (frequency 500-2000 Hz) was arranged on the outer surface of the 304 stainless steel pipe and heated to 300°C. The medium-frequency induction heating coil was moved so that all the pipes were in an environment of 300°C.

[0084] At the same time, a detachable head is used to seal the pipe so that the inside of the pipe is in a sealed state. A detachable head is connected through a vacuum pump to evacuate the inside of the pipe until the vacuum degree reaches 50 kPa. After keeping the temperature and pressure for 30 minutes, it is naturally cooled to obtain the corrosion-resistant pipe.

[0085] Example 6 This embodiment provides a specific corrosion-resistant pipe and a preparation method thereof, which specifically includes the following steps: 1) Pretreatment of pipes Except that pickling is not performed, the remaining steps are the same as 1) of Example 4.

[0086] 2) Composite corrosion-resistant composite film Same as 2) of Example 4.

[0087] Comparative Example 1 This comparative example provides a film.

[0088] Exactly the same as 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, the rest are the same.

[0089] Comparative Example 2 This comparative example provides a film.

[0090] Exactly the same as 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 are the same.

[0091] Comparative Example 3 This comparative example provides a film.

[0092] Exactly the same as Example 1, except that the raw materials for preparing the base film are replaced with: 70 parts by weight of PPS and 15 parts by weight of sulfonated modified PPS, the rest are the same.

[0093] Comparative Example 4 This comparative example provides a film.

[0094] Only the corrosion-resistant base film prepared in step 1) of Example 1 is provided.

[0095] Comparative Example 5 This comparative example provides a pipe.

[0096] Without pre-treating the pipe, the corrosion-resistant composite film prepared in Example 1 is directly and tightly attached to the inner surface of the pre-treated 304 stainless steel pipe, and the rest is the same as Example 4.

[0097] Comparative Example 6 This comparative example provides a pipe.

[0098] The silane coupling treatment in step 1-2) of Example 4 was not performed, and the rest was the same as Example 4.

[0099] Comparative Example 7 This comparative example provides a pipe.

[0100] The silane coupling treatment in step 1-2) of Example 4 was replaced by an acid pickling treatment, specifically: the 304 stainless steel pipe without oil stains and impurities after cleaning was completely immersed in hydrochloric acid (concentration of 5%, temperature of 50°C), soaked for 5 minutes, and then washed with deionized water until the titanium alloy pipe was neutral, and dried. The rest was the same as Example 4.

[0101] Comparative Example 8 This comparative example provides a pipe.

[0102] The same as in Example 4, except that in step 1-2), γ-aminopropyltriethoxysilane is replaced by vinyltrimethoxysilane (silane coupling agent A171), the other steps are the same.

[0103] Comparative Example 9 This comparative example provides a pipe.

[0104] The corrosion-resistant composite film used in Example 4 was replaced by the corrosion-resistant composite film prepared in Comparative Example 2, and the rest was the same as Example 4.

[0105] Comparative Example 10 The corrosion-resistant composite film used in Example 4 was replaced by the corrosion-resistant composite film prepared in Comparative Example 3, and the rest was the same as Example 4.

[0106] Comparative Example 11 The corrosion-resistant composite film used in Example 4 was replaced by the corrosion-resistant composite film prepared in Comparative Example 4, and the rest was the same as in Example 4.

[0107] The applicant conducted performance tests on the films prepared in Examples 1 to 3 and Comparative Examples 1 to 4, including tensile strength test, elongation at break test, water absorption test and salt spray test.

[0108] The specific test method is: The test method for tensile strength is carried out in accordance with GB / T 1040.3-2006.

[0109] The test method for elongation at break is carried out in accordance with GB / T 1040.3-2006.

[0110] The test method for water absorption is carried out in accordance with GB / T 1034-2008.

[0111] The test method of the salt spray test is carried out in accordance with GB / T 10125-2021, in which the acetic acid salt spray test (AASS) is used: a 5% sodium chloride acid solution with glacial acetic acid is added for atomization for testing, and a circulating spray method is adopted until corrosion occurs in the material to be tested. The time in Table 1 below is the time when corrosion occurs in the salt spray test.

[0112] The specific results are shown in Table 1 below.

[0113] Table 1

[0114] 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 for at least 1500 hours; while the films in Comparative Examples 1 and 4 showed spotty or cloud-like discoloration on the surface and local bubbles after 300 hours and 700 hours respectively, that is, corrosion; the film in Comparative Example 3 began to show spotty or cloud-like discoloration on the surface after 900 hours, that is, corrosion, indicating that the films in Examples 1 to 3 have good corrosion resistance. It can also be seen from Table 1 that the films in Examples 1 to 3 have a tensile strength of 62 to 68 MPa, an elongation at break of 5.8 to 6.5%, and a water absorption of 0.1 to 0.3‰, indicating that they have good mechanical properties. Low water absorption.

[0115] And it can be seen from Examples 1 to 3 and Comparative Example 1 that the film obtained when the content of sulfonated modified PPS is too high has poor mechanical properties and high water absorption, poor corrosion resistance, and does not meet 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 the sulfonated modified PPS; It can be seen 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 seen from Examples 1 to 3 and Comparative Example 4 that the setting of the nanocoating can increase the mechanical properties and corrosion resistance of the film to a certain extent.

[0116] 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 extremely low water absorption, indicating that it has good stability in complex application environments and excellent corrosion resistance.

[0117] The applicant also conducted performance tests on the pipes prepared in Examples 4 to 5 and Comparative Examples 5 to 11, including salt spray tests and adhesion tests.

[0118] The specific test method is: The test method of the salt spray test is carried out in accordance with GB / T 10125-2021, in which the acetic acid salt spray test (AASS) is used: a 5% sodium chloride acid solution with glacial acetic acid is added for atomization for testing, and a circulating spray method is adopted until corrosion occurs in the material to be tested. The time in Table 2 below is the time when corrosion occurs in the salt spray test.

[0119] The test method of adhesion experiment is carried out in accordance with GB / T 5210-2006.

[0120] The specific results are shown in Table 2 below.

[0121] Table 2 Remark Salt spray test(h) Adhesion test (MPa) Example 4 More than 1500 3.2 Example 5 More than 1500 3.0 Example 6 1300 2.7 Comparative Example 5 No pre-treatment of the pipe 500 1.5 Comparative Example 6 Pipe pretreatment only involves cleaning 550 1.8 Comparative Example 7 Pipe pretreatment for cleaning and pickling 630 2.1 Comparative Example 8 Replace other coupling agents 560 1.8 Comparative Example 9 Using the film without modified PPS in Comparative Example 2 550 1.6 Comparative Example 10 Using the film without reinforcement material in Comparative Example 3 900 2.8 Comparative Example 11 The film without nano coating in Comparative Example 4 was used 700 3.0 When only 304 stainless steel pipes were used for the same salt spray test, it was found that the 304 stainless steel pipes had slight white rust or pitting after 60 hours.

[0122] It can be seen from Examples 4 to 6 in Table 2 that the corrosion-resistant pipe provided by the invention has excellent corrosion resistance and can be maintained for at least 1300 hours without corrosion during the acetic acid salt spray test; and the film has strong adhesion to the surface of the pipe and can reach a pull-out strength of 2.7 to 3.2.

[0123] It can be seen from Example 4 and Comparative Examples 5-6 in Table 2 that the pipes in Comparative Examples 5-6 had local bubbles and local shedding of the film at 500 and 550 hours, respectively, which shows that pretreatment of the pipe is a very important technical means. If the pipe is not pretreated or only cleaned, the film has weak adhesion on the surface of the pipe and is easy to fall off, which leads to poor corrosion resistance of the pipe.

[0124] It can be seen from Example 4 and Comparative Example 7 in Table 2 that the pipe in Comparative Example 7 had local bubbles and local shedding of the film at 630 hours, which shows that it is very important to pre-treat the pipe with silane coupling in this application. If the pipe is only pre-treated with acid washing, the adhesion of the film on the pipe surface cannot be well increased, and the corrosion resistance of the pipe is poor.

[0125] It can be seen from Example 4 and Comparative Example 8 in Table 2 that the pipe in Comparative Example 8 had local bubbles and local shedding of the film at 560 hours, which shows that in the present application, the selection of silane coupling agent is also very specific. If other coupling agents that cannot react with sulfonic acid groups are used, the film has weak adhesion to the surface of the pipe, is easy to fall off, and the corrosion resistance of the pipe is poor.

[0126] It can be seen from Example 4 and Comparative Example 9 in Table 2 that the pipe in Comparative Example 9 had local bubbles and local shedding of the film at 550 hours, which shows that in the present application, the content of sulfonated modified PPS is a very important parameter limitation. If the content of sulfonated modified PPS is too low or not added, the adhesion ability of the film on the surface of the pipe is weak and the corrosion resistance of the pipe is poor.

[0127] It can be seen from Example 4 and Comparative Examples 10-11 in Table 2 that the pipes in Comparative Examples 10-11 showed spot-like or cloud-like discoloration at 900 and 700 hours, respectively, and local bubbles appeared in the film, which indicates that if a film without reinforcing material or nano-coating is used as a coating for the pipe, the corrosion resistance of the pipe is poor compared with Examples 4 and 5.

[0128] In summary, the thin film coating in the corrosion-resistant pipe provided by the present invention has a strong bonding ability with the metal pipe, the film has good adhesion ability, and the corrosion resistance of the pipe is excellent.

[0129] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall 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 includes a corrosion-resistant base film, and the corrosion-resistant base film includes 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 reinforcing material; the PPS is sulfonated and modified with concentrated sulfuric acid, and the degree of sulfonation of the sulfonated PPS is 8 to 15%.

2. The corrosion-resistant composite film according to claim 1, characterized in that: The reinforcing material includes one or more of glass fiber, carbon fiber, calcium carbonate and barium sulfate; And / or, the corrosion-resistant composite film further includes a nanolayer, and the nanolayer is composited on the corrosion-resistant base film.

3. The corrosion-resistant composite film according to claim 2, characterized in that: The number average molecular weight of the PPS is 6w~8w; And / or, the monofilament diameter of the glass fiber is 5-20 μm and the length is 5-10 μm; And / or, the carbon fiber has a diameter of 5-10 μm and a length of 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 sulfonation modification, the volume ratio of concentrated sulfuric acid to PPS is 7-12:1; the time is 1-3 hours; the temperature is 20-50°C; And / or, based on the total weight of the corrosion-resistant base film raw material, the nanolayer comprises the following raw material components: 2-4 wt% ZrO2, 1-3 wt% SiO2 and 0.5-2 wt% MMT; 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: after mixing the above-mentioned PPS, modified PPS and reinforcing materials in proportion, melt blending through a twin-screw extruder, extruding granulation and then high-temperature casting film to provide a corrosion-resistant base film.

5. The preparation method according to claim 4, characterized in that: Mix ZrO2, SiO2 and MMT in proportion to obtain a mixture, and compound the mixture on the surface of the corrosion-resistant base film to form a nanolayer, thereby obtaining a corrosion-resistant composite film; the compounding is performed by plasma spraying; And / or, 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 to 3; the thickness of the corrosion-resistant composite film is 20 to 80 μm.

7. A method for preparing a corrosion-resistant pipe according to claim 6, characterized in that: Provide a pipe and pretreat the inner surface of the pipe; provide a corrosion-resistant composite film as described in any one of claims 1 to 3, and completely and tightly fit the corrosion-resistant composite film on the inner surface of the pipe; perform high-temperature composite and cool to obtain the corrosion-resistant pipe.

8. The preparation method according to claim 7, characterized in that: The pretreatment includes one or more of sandblasting, grinding, cleaning, pickling, and silane coupling agent treatment; and / or, the temperature of high temperature compounding is 250-350°C; And / or, during high temperature compounding, the tube needs to be evacuated to maintain a vacuum degree of 50-100 kPa; And / or, a medium frequency induction heating coil is used to provide the temperature required for high temperature compounding.

9. The preparation method according to claim 8, characterized in that: The pickling treatment is performed using one or more of hydrochloric acid, sulfuric acid, dilute nitric acid or hydrofluoric acid; And / or, when the silane coupling agent is used for treatment, the silane coupling agent used contains one or more groups selected from epoxy group, amino group and isocyanate group; And / or, the frequency of the medium frequency induction heating coil is 500~2000Hz.

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

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