Preparation method and preparation device of hydrophilic oleophobic fluorinated ethylene propylene resin

Abstract

The invention provides a hydrophilic oleophobic fluorinated ethylene propylene resin preparation device which is characterized in that a stirrer (4) is positioned in the middle of a polymerization reaction kettle (1), a heating device is arranged at the bottom of the polymerization reaction kettle (1), the polymerization reaction kettle (1) is connected with a vacuumizing device (6), and the polymerization reaction kettle (1) is communicated with a dryer (9) through a condensation barrel (7), a demulsification device and a rinsing bath (8); the dryer (9) is connected with a powder vibrating screen (10); and the powder vibrating screen (10) is communicated with a finished product storage tank (11). According to the method disclosed by the invention, a functional monomer introduced with a hydrophilic group is added into a polymerization reaction kettle to react, tetrafluoroethylene and hexafluoropropylene are added to participate in copolymerization, and finally the fluororesin powder coating is prepared by the method and the device. The fluorinated ethylene propylene resin powder coating prepared by the method and the device has hydrophilic and oleophobic characteristics, the preparation process is simple and convenient, and the production cost is low.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, and specifically relates to a method and apparatus for preparing hydrophilic and oleophobic poly(fluoroethylene) propylene resin. Background Technology

[0002] Fluorinated powder coatings are functional powder coatings that use fluoropolymers as the main film-forming material. Due to the high weather resistance, corrosion resistance, and low surface energy of fluoropolymers, they occupy an important position in high-end industrial and civilian fields. However, the inherent hydrophobicity of fluoropolymers limits the application of fluorinated powder coatings in these fields. Controlling the hydrophilicity of fluorinated materials requires overcoming the contradiction between "low surface energy" and "hydrophilicity." The core strategy is to introduce hydrophilic groups or interfacial structures into the fluoropolymer through structural design or surface modification. Among these methods, amphiphilic copolymer design is commonly used. Through copolymerization, fluorinated hydrophobic segments and hydrophilic polar segments are combined to form "hydrophobic-hydrophilic" amphiphilic molecular chains. By controlling the ratio of "hydrophobic" to "hydrophilic" segments, the resulting fluorinated material can possess both hydrophilicity and the inherent oleophobicity of fluorinated materials. However, current equipment and methods for preparing hydrophilic and oleophobic fluorinated materials lack the necessary apparatus and methods, making it difficult for existing fluorinated powder coatings to meet current requirements. Summary of the Invention

[0003] This invention provides a method and apparatus for preparing hydrophilic and oleophobic poly(perfluoroethylene propylene) resin. The method and apparatus yield poly(perfluoroethylene propylene) resin powder coatings that exhibit hydrophilic and oleophobic properties. Furthermore, the preparation process is simple and convenient, and the production cost is low. The present invention adopts the following technical solution: a hydrophilic and oleophobic poly(fluoroethylene) propylene resin preparation device, which includes a polymerization reactor, a raw material inlet I at the top of the polymerization reactor, a raw material inlet II on the side of the polymerization reactor, a stirrer inside the polymerization reactor located in the middle of the polymerization reactor, a heating device at the bottom of the polymerization reactor, a vacuum device connected to the exhaust port on the side of the polymerization reactor, an outlet at the bottom of the polymerization reactor connected to the inlet of a coagulation tank, an outlet of the coagulation tank connected to a demulsification device in sequence, an outlet of the demulsification device connected to the inlet of a water washing tank, an outlet of the water washing tank connected to the inlet of a dryer, an outlet of the dryer connected to the inlet of a powder vibrating screen, and an outlet of the powder vibrating screen connected to a finished product storage tank.

[0004] Furthermore, the stirrer of the present invention is configured as a spiral stirrer, and the propeller blades of the spiral stirrer are located at the bottom of the polymerization reactor.

[0005] Furthermore, the heating device of the present invention includes two electric heating tubes, which are symmetrically distributed on the inner walls of both sides of the polymerization reactor.

[0006] Furthermore, the vacuuming device of the present invention is configured as a vacuum pump, the inlet of which is connected to the exhaust port on the side of the polymerization reactor, and the outlet of which is connected to an oxygen cylinder.

[0007] Furthermore, the demulsification device of the present invention includes a mixer, a multistage pump, and a centrifuge. The outlet of the coagulation tank is connected in sequence to the inlet of the mixer, and the outlet of the mixer is connected in sequence to the inlet of the washing tank through the multistage pump and the centrifuge.

[0008] This invention also discloses a method for preparing hydrophilic and oleophobic polytetrafluoroethylene propylene resin, the method comprising the following steps: Step 1: Deionized water, persulfate, sulfite initiator, and fluorine-containing dispersant are added to the polymerization reactor through raw material inlet I. The added solution is stirred using a spiral stirrer, and then the stirred mixture is heated to 100°C using two electric heating tubes. The polymerization reactor is then evacuated to remove oxygen using a vacuum pump, and the oxygen is stored in an external oxygen cylinder. The mass ratio of fluorine-containing dispersant to deionized water is 0.001~0.5. Step two: Then add tetrafluoroethylene, hexafluoropropylene monomers and functional monomers containing hydrophilic groups to the polymerization reactor, and then keep it warm and stir to carry out the copolymerization reaction. The molar ratio of the functional monomers to the total amount of tetrafluoroethylene and hexafluoropropylene monomers is 0.0001~0.1. Step 3: During the copolymerization process, tetrafluoroethylene, hexafluoropropylene, functional monomers and initiator solution are added to the polymerization reactor (1) in batches from raw material inlet II as needed. The molar ratio of the total amount of functional monomers added to the total amount of tetrafluoroethylene and hexafluoropropylene added is 0.0001~0.5. After the reaction is completed, a polymer dispersion is obtained. Step 4: The polymer dispersion is discharged into a coagulation tank. Then, an appropriate amount of acid is added to the polymer dispersion. The mixture is then demulsified by passing it through a mixer, a multistage pump, and a centrifuge in sequence to separate the hydrophilic and oleophobic poly(fluoroethylene propylene) resin. The separated hydrophilic and oleophobic poly(fluoroethylene propylene) resin is discharged into a water washing tank. The mass ratio of acid to polymer dispersion is 0.0001~0.1. Step 5: Then, the polytetrafluoroethylene propylene resin is washed multiple times with deionized water in a water washing tank. After washing, the fluoropolymer is dried in a dryer to obtain a powdered polymer. The polymer powder is then filtered through a powder vibrating screen to obtain a hydrophilic and oleophobic polytetrafluoroethylene propylene resin powder coating.

[0009] Furthermore, in step one of the present invention, the fluorinated dispersant is one or more of hexafluoropropylene oxide trimer carboxylate, perfluoropolyether carboxylate, and linear perfluoropolyether fluorocarbonate.

[0010] Furthermore, the functional monomer in step three of this invention is one or a mixture of sodium acrylate, potassium acrylate, ammonium acrylate, calcium acrylate, triethanolamine acrylate, sodium allyl sulfonate, potassium allyl sulfonate, triethanolamine allyl sulfonate, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoron-propyl vinyl ether, and perfluoroisopropyl vinyl ether.

[0011] Furthermore, the acid mentioned in step four of this invention is one or more of nitric acid, nitrous acid, sulfuric acid, sulfurous acid, oxalic acid, acetic acid, and citric acid.

[0012] This invention offers the following advantages: Using the preparation method and corresponding apparatus of this invention, one or more monomers, such as acrylates, allyl sulfonates, and perfluoroalkyl vinyl ethers, are added as functional monomers to a polymerization reactor to introduce hydrophilic groups. Simultaneously, tetrafluoroethylene and hexafluoropropylene are added for copolymerization. Ultimately, a fluoropolymer powder coating, i.e., a poly(perfluoroethylene propylene) resin powder coating with hydrophilic and oleophobic properties, is prepared using this method and apparatus. This property solves the difficulties in coatings such as "difficulty in cleaning due to oil stains" or "the need to keep the surface moist but repelling oils." Furthermore, the equipment of this invention has a simple structure, is easy to install, and uses a combination of commonly used equipment, significantly reducing production costs. The raw materials used in the preparation process of this invention, such as hexafluoropropylene oxide trimer carboxylates, perfluoropolyether carboxylates, linear perfluoropolyether fluorocarbonate dispersants, acrylates, allyl sulfonates, perfluoroalkyl vinyl ether monomers, nitric acid, nitrous acid, sulfuric acid, sulfurous acid, oxalic acid, acetic acid, and citric acid demulsifiers, are all commonly used and inexpensive, which is beneficial for industrialization. This invention enables the preparation of a stable fluorinated dispersion system using a preparation device. Tetrafluoroethylene, hexafluoropropylene, and functional monomers containing hydrophilic groups are gradually introduced in appropriate proportions for copolymerization, ultimately forming a polymer dispersion with an amphiphilic molecular structure of "hydrophilic-oleophobic". An acidic demulsifier is added to the dispersion, and the mixture is then sieved through a mechanical demulsifier, a cleaning device, a dryer, and a powder vibrating screen to obtain a hydrophilic and oleophobic fluororesin powder coating, further optimizing the properties of the obtained fluororesin powder coating. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0015] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0016] exist Figure 1 This invention provides a device for preparing hydrophilic and oleophobic poly(perfluoroethylene) propylene resin, comprising a polymerization reactor 1, a raw material inlet I2 at the top of the polymerization reactor 1, a raw material inlet II3 on ​​the side of the polymerization reactor 1, a stirrer 4 located in the middle of the polymerization reactor 1, a heating device at the bottom of the polymerization reactor 1, a vacuum device 6 connected to an exhaust port 5 on the side of the polymerization reactor 1, an outlet at the bottom of the polymerization reactor 1 connected to the inlet of a coagulation tank 7, an outlet of the coagulation tank 7 connected to a demulsification device, an outlet of the demulsification device connected to the inlet of a washing tank 8, an outlet of the washing tank 8 connected to the inlet of a dryer 9, and an outlet of the dryer 9 connected to the inlet of a powder vibrating screen 10. The outlet of 10 is connected to the finished product storage tank 11. The stirrer 4 used in this embodiment is a spiral stirrer. The propeller blade 12 of the spiral stirrer is located at the bottom of the polymerization reactor. The heating device used in this embodiment includes two electric heating tubes 13, which are symmetrically distributed on the inner walls of both sides of the polymerization reactor 1. The vacuum device 6 used in this embodiment is a vacuum pump. The inlet of the vacuum pump is connected to the exhaust port 5 on the side of the polymerization reactor 1. The outlet of the vacuum pump is connected to an oxygen cylinder 14. The demulsification device used in this embodiment includes a stirrer 15, a multistage pump 16, and a centrifuge 17. The outlet of the coagulation tank 7 is connected to the inlet of the stirrer 15 in sequence. The outlet of the stirrer 15 is connected to the inlet of the water washing tank 8 in sequence through the multistage pump 16 and the centrifuge 17.

[0017] This invention also discloses a method for preparing hydrophilic and oleophobic poly(fluoroethylene propylene) resin. The method includes the following steps: Step 1, adding deionized water, persulfate, sulfite initiator, and fluorinated dispersant into polymerization reactor 1 through raw material inlet I2; stirring the added solution with a spiral stirrer; then heating the stirred mixture to 100°C using two electric heating tubes 13; and then evacuating the polymerization reactor 1 to remove oxygen using a vacuum pump and storing the oxygen in an external oxygen cylinder 14; wherein the mass ratio of the fluorinated dispersant to deionized water is 0.001~0.5. In this embodiment, [the following method is used]. The fluorinated dispersant is one or more of the following: hexafluoropropylene oxide trimer carboxylate, perfluoropolyether carboxylate, and linear perfluoropolyether fluorocarbonate; Step two, tetrafluoroethylene, hexafluoropropylene monomers, and functional monomers containing hydrophilic groups are added to polymerization reactor 1, and then the mixture is kept warm and stirred to carry out the copolymerization reaction. The molar ratio of the functional monomer to the total amount of tetrafluoroethylene and hexafluoropropylene monomers is 0.0001~0.1; Step three, during the copolymerization process, tetrafluoroethylene, hexafluoropropylene, functional monomers, and initiator solution are added to polymerization reactor 1 in portions from raw material inlet II3 as needed. The total amount of functional monomers added is proportional to the total amount of tetrafluoroethylene and hexafluoropropylene monomers added. The molar ratio of the total amount of propylene added is 0.0001~0.5. After the reaction, a polymer dispersion is obtained. The functional monomers used in this embodiment are one or more of the following: sodium acrylate, potassium acrylate, ammonium acrylate, calcium acrylate, triethanolamine acrylate, sodium allyl sulfonate, potassium allyl sulfonate, triethanolamine allyl sulfonate, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoron-propyl vinyl ether, and perfluoroisopropyl vinyl ether. In step four, the polymer dispersion is discharged into the coagulation tank 7, and then an appropriate amount of acid is added to the polymer dispersion. Then, it is passed through the mixer 15, the multistage pump 16, and the centrifuge 17 in sequence. The process involves demulsification to separate the hydrophilic and oleophobic poly(fluoroethylene propylene) resin. The separated hydrophilic and oleophobic poly(fluoroethylene propylene) resin is discharged into a water washing tank 8. The mass ratio of acid to polymer dispersion is 0.0001~0.1. In this embodiment, the acid used is one or a mixture of nitric acid, nitrous acid, sulfuric acid, sulfurous acid, oxalic acid, acetic acid, and citric acid. Step five: The poly(fluoroethylene propylene) resin is then washed multiple times with deionized water in the water washing tank 8. After washing, the fluororesin is dried by a dryer 9 to obtain a powdered polymer. The polymer powder is then filtered through a powder vibrating screen 10 to obtain a hydrophilic and oleophobic poly(fluoroethylene propylene) resin powder coating.

[0018] The technical solution of the present invention will be further explained below with reference to several preferred embodiments. However, the experimental conditions and setting parameters therein should not be regarded as limitations on the basic technical solution of the present invention, and the protection scope of the present invention is not limited to the following embodiments. Example

[0019] Step 1: Add 2800L of deionized water, 10kg of 10wt% linear perfluoropolyether fluorocarbonate solution, 20kg of 20wt% perfluoropolyether carboxylate solution, 5kg of 10wt% potassium persulfate solution, 5kg of 10wt% ammonium persulfate solution, and 2.2kg of 5wt% sodium sulfite solution to the polymerization reactor 1. After stirring evenly, raise the temperature to 100℃, keep it at this temperature, and then vacuum and deoxygenate for 30 minutes. Step 2: 30 kg of tetrafluoroethylene, 150 kg of hexafluoropropylene, and 10 kg of 20 wt% potassium acrylate solution are introduced into polymerization reactor 1. The mixture is kept warm and stirred to start the polymerization reaction. Step 3: After reacting for 30 minutes, 110 kg of tetrafluoroethylene, 10 kg of hexafluoropropylene, 2 kg of 20 wt% potassium acrylate solution, and 2 kg of 10 wt% potassium persulfate solution are introduced into polymerization reactor 1, and the mixture is stirred and kept at the desired temperature. After another 30 minutes, the same mixture is introduced again, and the mixture is stirred and kept at the desired temperature. This process of adding monomers and initiator solutions is repeated a total of 6 times. After the final addition, the mixture is kept at the desired temperature for 30 minutes to obtain a polymer dispersion. Step 4: The polymer dispersion is introduced into the coagulation tank 7, and 40 kg of 10 wt% nitric acid solution and 30 kg of 10 wt% citric acid solution are added. After stirring and demulsifying for 60 min, the fluoropolymer floats on the surface of the coagulated liquid. The lower layer of coagulated liquid is discharged, and an appropriate amount of deionized water is added and stirred and washed for 30 min. The lower layer of wash water is then discharged, and an appropriate amount of deionized water is introduced and stirred and washed for another 30 min. The fluoropolymer floating on the wash water is separated and sent to the dryer 9 for dehydration and drying. The dehydrated and dried fluoropolymer powder is filtered through a 200-mesh powder vibrating screen 10 to obtain a "hydrophilic and oleophobic" polytetrafluoroethylene propylene resin powder coating. Example

[0020] Step 1: Add 2000L of deionized water, 20kg of 10wt% linear perfluoropolyether fluorocarbonate solution, 10kg of 20wt% perfluoropolyether carboxylate solution, 4kg of 10wt% potassium persulfate solution, 4kg of 10wt% ammonium persulfate solution, and 1.8kg of 5wt% potassium sulfite solution to polymerization reactor 1. After stirring evenly, heat to 100℃, keep warm and vacuum to remove oxygen for 20min. Step 2: 20 kg of tetrafluoroethylene, 140 kg of hexafluoropropylene, 5 kg of 20 wt% ammonium acrylate solution, and 10 kg of 10 wt% triethanolamine acrylate solution are introduced into polymerization reactor 1. The mixture is kept warm and stirred to start the polymerization reaction. Step 3: After reacting for 30 minutes, 100 kg of tetrafluoroethylene, 10 kg of hexafluoropropylene, 1 kg of 20 wt% ammonium acrylate solution, 3 kg of 10 wt% triethanolamine acrylate solution, 1 kg of 10 wt% potassium persulfate solution, and 2 kg of 10 wt% ammonium persulfate solution are introduced into polymerization reactor 1. The mixture is stirred and kept at a constant temperature. After another 30 minutes, the same mixture is introduced again, and the mixture is stirred and kept at a constant temperature. This process of adding monomers and initiator solutions is repeated a total of 5 times. After the final addition, the mixture is kept at a constant temperature for 30 minutes to obtain a polymer dispersion. Step 4: The polymer dispersion is introduced into the coagulation tank 7, and 30 kg of 10 wt% nitric acid solution and 10 kg of 10 wt% sulfuric acid solution are added. After stirring and demulsifying for 60 min, the fluoropolymer floats on the surface of the coagulated liquid. The lower layer of coagulated liquid is discharged, and an appropriate amount of deionized water is added and stirred and washed for 20 min. The lower layer of wash water is then discharged, and an appropriate amount of deionized water is introduced and stirred and washed for another 20 min. The fluoropolymer floating on the wash water is separated and sent to the dryer 9 for dehydration and drying. The dehydrated and dried fluoropolymer powder is filtered through a 300-mesh powder vibrating screen 10 to obtain a "hydrophilic and oleophobic" polytetrafluoroethylene propylene resin powder coating. Example

[0021] Step 1: Add 3000L of deionized water, 10kg of 10wt% hexafluoropropylene oxide carboxylate solution, 15kg of 20wt% perfluoropolyether carboxylate solution, 5kg of 10wt% potassium persulfate solution, 10kg of 10wt% ammonium persulfate solution, and 4kg of 5wt% sodium bisulfite solution to polymerization reactor 1. After stirring evenly, heat to 100℃, keep warm, and vacuum to remove oxygen for 30min. Step 2: 20 kg of tetrafluoroethylene, 140 kg of hexafluoropropylene, 5 kg of 15 wt% sodium allyl sulfonate solution, and 10 kg of 10 wt% triethanolamine allyl sulfonate solution are introduced into polymerization reactor 1. The mixture is kept warm and stirred to start the polymerization reaction. Step 3: After reacting for 30 minutes, 140 kg of tetrafluoroethylene, 15 kg of hexafluoropropylene, 2 kg of 15 wt% sodium allyl sulfonate solution, 1 kg of 10 wt% triethanolamine allyl sulfonate solution, 1 kg of 10 wt% potassium persulfate solution, and 2 kg of 10 wt% ammonium persulfate solution are introduced into polymerization reactor 1. The mixture is stirred and kept at a constant temperature. After another 30 minutes, the same mixture is introduced again, and the mixture is stirred and kept at a constant temperature. This process is repeated a total of 5 times. After the last addition, the mixture is kept at a constant temperature for 30 minutes to obtain a polymer dispersion. Step 4: The polymer dispersion is introduced into the coagulation tank 7, and 10 kg of 20 wt% nitric acid solution and 10 kg of 10 wt% oxalic acid solution are added. After stirring and demulsifying for 60 min, the fluoropolymer floats on the surface of the coagulated liquid. The lower layer of coagulated liquid is discharged, and an appropriate amount of deionized water is added and stirred and washed for 30 min. The lower layer of wash water is then discharged, and an appropriate amount of deionized water is introduced and stirred and washed for another 30 min. The fluoropolymer floating on the wash water is separated and sent to the dryer 9 for dehydration and drying. The dehydrated and dried fluoropolymer powder is filtered through a 200-mesh powder vibrating screen 10 to obtain a "hydrophilic and oleophobic" polytetrafluoroethylene propylene resin powder coating. Example

[0022] Step 1: Add 3200L of deionized water, 15kg of 20wt% perfluoropolyether carboxylate solution, 10kg of 10wt% linear perfluoropolyether fluorocarbonate solution, 6kg of 10wt% potassium persulfate solution, 12kg of 10wt% ammonium persulfate solution, and 4.5kg of 5wt% sodium persulfate solution to polymerization reactor 1. After stirring evenly, raise the temperature to 100℃, keep it at this temperature, and then vacuum and deoxygenate for 30 minutes. Step 2: 30 kg of tetrafluoroethylene, 140 kg of hexafluoropropylene, and 1 kg of perfluoropropyl vinyl ether are introduced into polymerization reactor 1. The mixture is kept at a constant temperature and stirred to start the polymerization reaction. Step 3: After reacting for 30 minutes, 120 kg of tetrafluoroethylene, 15 kg of hexafluoropropylene, 0.5 kg of perfluoropropyl vinyl ether, 1 kg of 10 wt% potassium persulfate solution, and 2 kg of 10 wt% ammonium persulfate solution are introduced into polymerization reactor 1, and the mixture is stirred and kept at a constant temperature. After another 30 minutes, 120 kg of tetrafluoroethylene, 15 kg of hexafluoropropylene, 0.5 kg of perfluoropropyl vinyl ether, 1 kg of 10 wt% potassium persulfate solution, and 2 kg of 10 wt% ammonium persulfate solution are introduced again, and the mixture is stirred and kept at a constant temperature. This process is repeated a total of 6 times. After the last addition, the mixture is kept at a constant temperature for 30 minutes to obtain a polymer dispersion. Step 4: The polymer dispersion is introduced into the coagulation tank 7, and 10 kg of 20 wt% nitric acid solution and 20 kg of 10 wt% citric acid solution are added. After stirring and demulsifying for 60 min, the fluoropolymer floats on the surface of the coagulated liquid. The lower layer of coagulated liquid is discharged, and an appropriate amount of deionized water is added and stirred and washed for 30 min. The lower layer of wash water is then discharged, and an appropriate amount of deionized water is introduced and stirred and washed for another 30 min. The fluoropolymer floating on the wash water is separated and sent to the dryer 9 for dehydration and drying. The dehydrated and dried fluoropolymer powder is filtered through a 300-mesh powder vibrating screen 10 to obtain a "hydrophilic and oleophobic" polytetrafluoroethylene propylene resin powder coating. Example

[0023] Step 1: Add 3200L of deionized water, 10kg of 10wt% hexafluoropropylene oxide carboxylate solution, 10kg of 20wt% perfluoropolyether carboxylate solution, 6kg of 10wt% potassium persulfate solution, 12kg of 10wt% ammonium persulfate solution, and 5kg of 5wt% sodium sulfite solution to polymerization reactor 1. After stirring evenly, heat to 100℃, keep warm, and vacuum to remove oxygen for 30min. Step 2: 30 kg of tetrafluoroethylene, 140 kg of hexafluoropropylene, and 0.8 kg of perfluoroethyl vinyl ether are introduced into polymerization reactor 1. The mixture is kept at a constant temperature and stirred to start the polymerization reaction. Step 3: After reacting for 30 minutes, 120 kg of tetrafluoroethylene, 15 kg of hexafluoropropylene, 0.6 kg of perfluoroethyl vinyl ether, 1 kg of 10 wt% potassium persulfate solution, and 2 kg of 10 wt% ammonium persulfate solution are introduced into polymerization reactor 1, and the mixture is stirred and kept at the desired temperature. After another 30 minutes, the same mixture is introduced again, and the mixture is stirred and kept at the desired temperature. This process is repeated a total of 6 times. After the last addition, the mixture is kept at the desired temperature for 30 minutes to obtain a polymer dispersion. Step 4: The polymer dispersion is introduced into the coagulation tank 7, and 10 kg of 20 wt% nitric acid solution and 20 kg of 10 wt% acetic acid solution are added. After stirring and demulsifying for 60 min, the fluoropolymer floats on the surface of the coagulated liquid. The lower layer of coagulated liquid is discharged, and an appropriate amount of deionized water is added and stirred and washed for 30 min. The lower layer of wash water is then discharged, and an appropriate amount of deionized water is introduced and stirred and washed for another 30 min. The fluoropolymer floating on the wash water is separated and sent to the dryer 9 for dehydration and drying. The dehydrated and dried fluoropolymer powder is filtered through a 300-mesh powder vibrating screen 10 to obtain a "hydrophilic and oleophobic" polytetrafluoroethylene propylene resin powder coating.

[0024] The poly(fluoroethylene propylene) resin powder coatings prepared in Examples 1, 2, 3, 4, and 5 were coated onto 304 stainless steel sheets using a roller coating method. The coating thickness was 2 mm. The sheets were cut into appropriate sizes and marked as samples 1, 2, 3, 4, and 5.

[0025] Comparative example: Weigh out the poly(perfluoroethylene) propylene granules (brand name Miflon). ® 1181P) was placed into the mold and hot-pressed for 10 minutes at 300℃ and 20MPa using a flat vulcanizing machine; then it was cold-pressed for 5 minutes at room temperature and 10MPa to finally obtain a 2mm thick sheet, which was marked as sample 6.

[0026] The static water contact angle (WCA) and mineral oil contact angle (OCA) of the fluoropolymer coatings of samples 1, 2, 3, 4, and 5, and sample 6 were measured using a contact angle meter to compare their hydrophilic and oleophobic properties. The test results are shown in the table below: As shown in the table above, typical perfluoroethylene propylene materials have very low surface energy, exhibiting hydrophobic and oleophobic properties. The coating formed by the "hydrophilic and oleophobic" fluororesin powder coating of this invention retains the oleophobic properties of fluorinated materials while also possessing hydrophilic properties. This demonstrates that the hydrophilic groups introduced into the polymer molecular structure significantly alter the hydrophilic and hydrophobic properties of perfluoroethylene propylene.

[0027] Not limited to this, any variations or substitutions conceived without inventive effort should be included within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the scope defined in the claims.

Claims

1. An apparatus for preparing hydrophilic and oleophobic poly(fluoroethylene) propylene resin, characterized in that... It includes a polymerization reactor (1), with a raw material inlet I (2) at the top of the polymerization reactor (1) and a raw material inlet II (3) on the side of the polymerization reactor (1). A stirrer (4) is provided inside the polymerization reactor (1), and the stirrer (4) is located in the middle of the polymerization reactor (1). A heating device is provided at the bottom of the polymerization reactor (1). A vacuum device (6) is connected to the exhaust port (5) on the side of the polymerization reactor (1). The outlet at the bottom of the polymerization reactor (1) is connected to the inlet of the coagulation tank (7). The outlet of the coagulation tank (7) is connected to the demulsification device in sequence. The outlet of the demulsification device is connected to the inlet of the water washing tank (8). The outlet of the water washing tank (8) is connected to the inlet of the dryer (9). The outlet of the dryer (9) is connected to the inlet of the powder vibrating screen (10). The outlet of the powder vibrating screen (10) is connected to the finished product storage tank (11).

2. The apparatus for preparing hydrophilic and oleophobic polytetrafluoroethylene propylene resin according to claim 1, characterized in that... The stirrer (4) is configured as a spiral stirrer, and the propeller blades (12) of the spiral stirrer are located at the bottom of the polymerization reactor (1).

3. The apparatus for preparing hydrophilic and oleophobic polytetrafluoroethylene propylene resin according to claim 1, characterized in that... The heating device includes two electric heating tubes (13), which are symmetrically distributed on the inner walls of both sides of the polymerization reactor (1).

4. The apparatus for preparing hydrophilic and oleophobic polytetrafluoroethylene propylene resin according to claim 1, characterized in that... The vacuum pump (6) is configured as a vacuum pump. The inlet of the vacuum pump is connected to the exhaust port (5) on the side of the polymerization reactor (1), and the outlet of the vacuum pump is connected to an oxygen (14) cylinder.

5. The apparatus for preparing hydrophilic and oleophobic polytetrafluoroethylene propylene resin according to claim 1, characterized in that... The demulsification device includes a mixer (15), a multistage pump (16) and a centrifuge (17). The outlet of the coagulation tank (7) is connected to the inlet of the mixer (15) in sequence. The outlet of the mixer (15) is connected to the inlet of the washing tank (8) in sequence through the multistage pump (16) and the centrifuge (17).

6. A method for preparing hydrophilic and oleophobic poly(fluoroethylene propylene) resin, characterized in that the method... Includes the following steps: Step 1: Deionized water, persulfate, sulfite initiator and fluorine-containing dispersant are added into the polymerization reactor (1) through the raw material inlet I (2). The added solution is stirred by a spiral stirrer. Then, the mixed solution after stirring is heated to 100°C by two electric heating tubes (13). The polymerization reactor (1) is then evacuated by a vacuum pump to remove oxygen and the oxygen is stored in an external oxygen cylinder (14). The mass ratio of fluorine-containing dispersant to deionized water is 0.001~0.

5. Step 2: Then add tetrafluoroethylene, hexafluoropropylene monomers and functional monomers containing hydrophilic groups to the polymerization reactor (1), and then keep it warm and stir to carry out the copolymerization reaction. The molar ratio of the functional monomers to the total amount of tetrafluoroethylene and hexafluoropropylene monomers is 0.0001~0.

1. Step 3: During the copolymerization process, tetrafluoroethylene, hexafluoropropylene, functional monomers and initiator solutions are added to the polymerization reactor (1) in batches from raw material inlet II (3) as needed. The molar ratio of the total amount of functional monomers added to the total amount of tetrafluoroethylene and hexafluoropropylene added is 0.0001~0.

5. After the reaction is completed, a polymer dispersion is obtained. Step 4: The polymer dispersion is discharged into the coagulation tank (7), and then an appropriate amount of acid is added to the polymer dispersion. Then, the demulsification operation is carried out by the mixer (15), the multi-stage pump (16) and the centrifuge (17) in sequence to separate the hydrophilic and oleophobic polytetrafluoroethylene propylene resin. The separated hydrophilic and oleophobic polytetrafluoroethylene propylene resin is discharged into the water washing tank (8). The mass ratio of acid to polymer dispersion is 0.0001~0.

1. Step 5: Then, the polytetrafluoroethylene propylene resin is washed multiple times with deionized water in the water washing tank (8). After washing, the fluoropolymer is dried by the dryer (9) to obtain a powdered polymer. The polymer powder is filtered through the powder vibrating screen (10) to obtain a hydrophilic and oleophobic polytetrafluoroethylene propylene resin powder coating.

7. The method for preparing hydrophilic and oleophobic polytetrafluoroethylene propylene resin according to claim 1, characterized in that... In step one, the fluorinated dispersant is one or a mixture of hexafluoropropylene oxide trimer carboxylate, perfluoropolyether carboxylate, and linear perfluoropolyether fluorocarbonate.

8. The method for preparing hydrophilic and oleophobic polytetrafluoroethylene propylene resin according to claim 1, characterized in that... In step three, the functional monomers are one or more of the following: sodium acrylate, potassium acrylate, ammonium acrylate, calcium acrylate, triethanolamine acrylate, sodium allyl sulfonate, potassium allyl sulfonate, triethanolamine allyl sulfonate, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoron-propyl vinyl ether, and perfluoroisopropyl vinyl ether.

9. The method for preparing hydrophilic and oleophobic polytetrafluoroethylene propylene resin according to claim 1, characterized in that... The acid mentioned in step four is one or a mixture of nitric acid, nitrous acid, sulfuric acid, sulfurous acid, oxalic acid, acetic acid, and citric acid.

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