High toughness chlorine-containing copolymer-based filtration membrane and method for preparing the same

Abstract

The application discloses a high-toughness chlorine-containing copolymer-based filter membrane and a preparation method thereof. The main component of the high-toughness chlorine-containing copolymer-based filter membrane is a vinyl chloride-acrylate copolymer and a crosslinked product thereof. The preparation method of the high-toughness chlorine-containing copolymer-based filter membrane comprises the following steps: solidifying and forming a membrane-forming liquid containing the vinyl chloride-acrylate copolymer and additives through a dry-wet spinning process, and performing a partial crosslinking reaction after the solidification and forming. The prepared chlorine-containing copolymer-based filter membrane has the advantages of high toughness, high open porosity, large flux, simple preparation process and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of membrane separation, and particularly relates to the technical field of a high-toughness chlorine-containing copolymer-based filter membrane and a preparation method thereof. BACKGROUND

[0002] Membrane separation technology has great application potential in the industrial field because of high efficiency, simple equipment, convenient operation, energy saving and environmental protection, and the application range thereof has been extended to the fields of biology, medicine, environmental protection, energy, seawater desalination and wastewater treatment.

[0003] Polyvinyl chloride (PVC) is one of the three largest synthetic resins in terms of output, and is an important chlorine-containing polymer. PVC is abundant in source, low in price, good in chemical stability, resistant to bacteria, acid and alkali, and chemical corrosion, and is widely used in the preparation of ultrafiltration membranes and microfiltration membranes for water treatment. In addition, PVC can be dissolved in a variety of polar solvents, and the membrane preparation cost is low. The research on PVC as a membrane material and a preparation method thereof has been reported at home and abroad. More representative ones are as follows: Chinese patent (CN 1579600A) reports a polyvinyl chloride / chloroethylene-vinyl acetate-maleic anhydride ternary copolymer alloy hollow filter membrane and a preparation method thereof. Chinese patent (CN 101195084A) reports a self-assembled hydrophilic modification method for the surface of a PVC alloy ultrafiltration membrane, and the PVC membrane flux reaches 1000 L / m 2 h. Chinese patent (CN 200810062570.8) discloses a preparation method of a hydrophilic polyvinyl chloride alloy ultrafiltration membrane. An amphiphilic graft copolymer of polyvinyl chloride is synthesized by an atom transfer radical polymerization method, and the amphiphilic graft copolymer is used as a hydrophilic modifier to blend with polyvinyl chloride to prepare a polyvinyl chloride alloy ultrafiltration membrane with controllable structure, hydrophilicity, anti-pollution, large flux and high retention rate by a solution phase inversion method. A series of Chinese patents (CN201811062841.X, CN201811063844.5, CN201811062838.8, CN201810191903.0, CN201410730313.2, CN201510057782.7, CN201510058518.5, CN201510059113.3, CN201410734459.4) use chloroethylene copolymers or modified PVC for membrane preparation, and endow the filter membrane with different chemical structures and membrane properties. The main innovation is that the properties of the filter membrane, such as the retention of substances, membrane hydrophilicity, membrane antibacterial and anti-pollution, are innovated, the application range of the chlorine-containing polymer filter membrane is expanded, and the service life of the chlorine-containing polymer filter membrane is prolonged.

[0004] However, as a rigid material, PVC is limited in its application due to its insufficient toughness. Of course, as a filter membrane material, it is prone to cracking or breaking of the membrane wire during use, especially under long-term severe aeration conditions. Therefore, it is of great significance to prepare high-toughness and high-flux chlorine-containing polymer filter membranes through certain modification methods. The main research direction of PVC toughening modification is the toughening modification of PVC profile preparation, including nano-particle filling, elastomer material compounding, and inorganic nano-fiber reinforcement. However, due to the particularity of the phase inversion method for preparing filter membranes, the modifier used in the membrane preparation liquid needs to have good solubility and compatibility, so the methods for toughening modification of PVC filter membranes are very limited. Chinese patent (CN 112999893 A) discloses a PVC composite ultrafiltration membrane prepared by dispersing synthetic para-aramid nanospheres in a PVC matrix. Compared with pure PVC ultrafiltration membrane, its mechanical properties are greatly improved, but the synthesis of aramid nanospheres from phthaloyl chloride and p-phenylenediamine is very complicated and difficult to scale up. Chinese patent (CN200810189737.7) discloses a PVDF and PVC blended ultrafiltration membrane and its preparation method. The toughening agent used is chlorinated polyvinyl chloride, nitrile rubber, polyurethane, ABS, etc. Since PVDF itself has excellent toughness, the addition of toughening agent is not for the toughening modification of PVC. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art and provide a high-toughness chlorine-containing copolymer-based filter membrane and a preparation method thereof. Unlike existing filter membrane materials and their preparation techniques, the present application discloses a high-toughness chlorine-containing copolymer-based filter membrane and a preparation method thereof. The disclosed high-toughness chlorine-containing copolymer-based filter membrane has good toughness, stable structure and performance, high open porosity, and large flux, and is suitable for various membrane water treatment equipment and engineering. The disclosed preparation method has the characteristics of strong controllability of membrane structure and performance during preparation, simple process, and low manufacturing cost.

[0006] The technical scheme of the present application is as follows:

[0007] The present application first provides a preparation method of a high-toughness chlorine-containing copolymer-based filter membrane, the steps of which are as follows:

[0008] 1) Mix chlorovinyl-acrylate copolymer with a weight percentage of 20-40%, pore size regulator with a weight percentage of 1-5%, thermal stabilizer with a weight percentage of 0.1-1%, and solvent with a weight percentage of 55-75%, and stir and dissolve at 50-70°C to form a uniform membrane preparation liquid; the pore size regulator is polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), or glycerol;

[0009] 2) extruding the membrane-forming solution from the spinneret to form a tubular liquid membrane which uniformly coats the substance in the center tube of the spinneret, and the liquid membrane enters the coagulation bath vertically after passing through an air gap of 0-20 cm to solidify into a hollow fiber membrane; the substance in the center tube of the spinneret is deionized water or a support tube;

[0010] 3) passing the hollow fiber membrane solidified in the coagulation bath in step 2) through a 40-55℃ air blowing tunnel for 30-60s to dry the membrane surface, then immersing it in a solution of pyromellitic dianhydride, and continuing to pass through a 40-55℃ air blowing tunnel for 10-30s, and then rinsing with water to obtain a high-toughness chlorine-containing copolymer-based filtration membrane.

[0011] Further, the chloroethylene-acrylate copolymer is one or more of poly(chloroethylene-butyl acrylate-hydroxyethyl acrylate), poly(chloroethylene-hexyl acrylate-hydroxyethyl acrylate), poly(chloroethylene-octyl acrylate-hydroxyethyl acrylate), poly(chloroethylene-butyl acrylate-hydroxypropyl acrylate), poly(chloroethylene-hexyl acrylate-hydroxypropyl acrylate), or poly(chloroethylene-octyl acrylate-hydroxypropyl acrylate).

[0012] Further, the monomer composition of the chloroethylene-acrylate copolymer is 50-80% by weight of chloroethylene, 15-40% of acrylate, and 3-10% of hydroxyalkyl acrylate; the acrylate is butyl acrylate, hexyl acrylate, or octyl acrylate; and the hydroxyalkyl acrylate is hydroxyethyl acrylate or hydroxypropyl acrylate.

[0013] Further, the number average molecular weight of the chloroethylene-acrylate copolymer is 40,000-100,000 Da.

[0014] Further, the heat stabilizer is zinc stearate, calcium stearate, tributyltin chloride, dibutyltin diacetate, dibutyltin maleate, methyltin mercaptide, dibutyltin dilaurate, or di-n-octyltin dilaurate; the solvent is N,N'-dimethylformamide (DMF), N,N'-dimethylacetamide (DMAc), or N-methylpyrrolidone (NVP); and the support tube is a polymeric fiber braided tube, and the material of the support tube is polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), or aramid.

[0015] Further, the composition of the pyromellitic dianhydride solution is 30-60% by weight of pyromellitic dianhydride and 40-70% by weight of solvent; and the solvent in the pyromellitic dianhydride solution is N,N'-dimethylformamide (DMF), N,N'-dimethylacetamide (DMAc), or N-methylpyrrolidone (NVP).

[0016] Further, the hollow fiber membrane is immersed in the pyromellitic dianhydride solution for 1-5 seconds.

[0017] The application further provides a high-toughness chlorine-containing copolymer-based filter membrane prepared by the method.

[0018] Further, the high-toughness chlorine-containing copolymer-based filter membrane comprises 95-99.5% of the chloroethylene-acrylate copolymer and 0.5-5% of the crosslinked product of the chloroethylene-acrylate copolymer, wherein the crosslinked product of the chloroethylene-acrylate copolymer is a product after the chloroethylene-acrylate copolymer is reacted with pyromellitic dianhydride.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] The high-toughness chlorine-containing copolymer-based filter membrane disclosed by the application adopts a specific chloroethylene-acrylate copolymer as a main substrate, and the special copolymer structure of the chemical structure makes the chloroethylene-acrylate copolymer have excellent toughness and softness, and the filter membrane prepared by the chloroethylene-acrylate copolymer completely overcomes the defects of poor toughness and easy cracking of the PVC filter membrane, and has the advantages of bacteria resistance, acid and alkali resistance, chemical corrosion resistance and the like which are necessary for a separation membrane material.

[0021] In addition, the preparation method of the high-toughness chlorine-containing copolymer-based filter membrane disclosed by the application combines a tubular liquid membrane one-time spinning solidification forming process with a simple crosslinking process. The process is simple, convenient and efficient, and a variety of pore structures can be obtained by changing a few process parameters, and the membrane structure is controllable and the production repeatability is good.

[0022] In addition, the preparation method of the high-toughness chlorine-containing copolymer-based filter membrane disclosed by the application forms a partial crosslinked product of the chloroethylene-acrylate copolymer on the outer surface of the membrane through the crosslinking process, and the pore structure of the membrane surface and the softness of the membrane surface can be adjusted through the process, so that the toughness of the membrane is improved, the strength is increased, and the comprehensive mechanical properties of the membrane are improved.

[0023] In addition, the preparation method of the high-toughness chlorine-containing copolymer-based filter membrane disclosed by the application forms a partial crosslinked product of the chloroethylene-acrylate copolymer on the outer surface of the membrane through the crosslinking process, and a small amount of carboxyl groups can be formed on the membrane surface through the process, the hydrophilicity of the membrane surface is increased, and the pollution resistance of the membrane is enhanced.

[0024] Furthermore, the vinyl chloride-acrylate copolymer disclosed in this invention has, firstly, a low glass transition temperature, which affects the arrangement of polymer molecules during curing, resulting in an extremely loose cross-sectional structure in the filter membrane, thereby significantly reducing filtration resistance and increasing flux. Secondly, the vinyl chloride-acrylate copolymer contains some hydroxyl groups, which increases the hydrophilicity of the membrane surface, enhancing the membrane fibers' resistance to fouling, and provides active sites for the crosslinking process, enabling subsequent crosslinking operations. Finally, the vinyl chloride-acrylate copolymer does not leak during membrane fabrication and use, ensuring the long-term stability of the membrane's composition, physical structure, and performance. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a vinyl chloride-acrylate copolymer in a high-toughness chlorine-containing copolymer-based filter membrane.

[0026] Figure 2 This is a schematic diagram of the crosslinking reaction of vinyl chloride and acrylate copolymers in a high-toughness chlorine-containing copolymer-based filter membrane and the structure of its products.

[0027] Figure 3 These are SEM images of the surface and cross-section of a high-toughness chlorine-containing copolymer-based filter membrane sample. Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific embodiments. The implementation steps of all embodiments are the same as those described above. The parameters in the table represent the implementation conditions and the resulting membrane structure and properties. It should be noted that the embodiments described do not constitute a limitation of the present invention. All modifications that can be directly derived or conceived by those skilled in the art from the content disclosed in this invention should be considered within the scope of protection of this invention.

[0029] The chloroethylene-acrylate copolymer in the present application can be prepared by suspension polymerization and other polymerization methods. The general method of the preparation method can be: adding deionized water, dispersant, initiator into the polymerization kettle, vacuumizing and filling nitrogen repeatedly for 3 times, then adding solubilizer and formula amount of chloroethylene monomer, pre-dispersing and stirring at room temperature. Heating to the polymerization temperature, starting to gradually add formula amount of comonomer (i.e. corresponding acrylate and hydroxyalkyl acrylate), and carrying out polymerization reaction. When the reaction needs to end, air is introduced into the system to terminate the reaction. Discharging, filtering, washing, and extracting the solubilizer with methanol, and drying to obtain the chloroethylene-acrylate copolymer. The preparation methods of different chloroethylene-acrylate copolymers can be different in comonomer, dispersant, initiator, solubilizer, dropping time, reaction temperature and reaction time. The dispersant, initiator and solubilizer are all well-known concepts in the polymerization field, and their specific types and amounts can be selected as needed. The dispersant can be selected from polyvinyl alcohol, hydroxyl cellulose and the like; the initiator can be selected from azo initiator, oil-soluble peroxide initiator and the like; the solubilizer can be selected from propyl formate, butyl formate and other alkyl acid alkyl esters. Their selection will not have essential influence on the product, and the present application does not specifically limit their types and amounts. Taking poly(chloroethylene-butyl acrylate-hydroxyethyl acrylate) as an example, the preparation method adopts the following steps: adding 2000ml deionized water, 1.2g dispersant solution, 1g initiator into a stainless steel reaction kettle, vacuumizing and filling nitrogen repeatedly for 3 times, then adding 1600g chloroethylene, 7.5g solubilizer, pre-dispersing and stirring at room temperature for 30 minutes. Heating to 50℃ polymerization temperature, starting to gradually add 300g butyl acrylate and gradually add 100g hydroxyethyl acrylate, and carrying out polymerization reaction. The dropping time is 4-6h, the reaction time is 12 hours, air is introduced into the system to terminate the reaction. Discharging, filtering, washing, and extracting the solubilizer with 500g methanol, and drying at 50℃ to obtain poly(chloroethylene-butyl acrylate-hydroxyethyl acrylate).

[0030] Example 1.

[0031] The preparation steps and structure and performance characterization methods of the high-toughness chlorine-containing copolymer-based filtration membrane are as follows:

[0032] 1) 300g poly(chloroethylene-butyl acrylate-hydroxyethyl acrylate), 30g polyethylene glycol, 5g tributyltin chloride and 665g N,N'-dimethylformamide (DMF) are mixed to form a uniform membrane-forming solution by stirring and dissolving at 67℃ for 24h, and vacuum degassing for 2h;

[0033] 2) Deionized water at 40℃ is passed through the center tube of the spinneret, and the membrane-forming solution of step 1) is extruded from the outer ring of the spinneret to form a tubular liquid membrane, which is vertically introduced into a 40℃ coagulation bath after passing through an air gap of 10cm to solidify into a hollow fiber membrane;

[0034] 3) The hollow fiber membrane obtained from the coagulation bath in step 2) was passed through a 40°C air blowing tunnel for 60s, immersed in and passed through a 30% by weight solution of pyromellitic dianhydride in DMF for 5s, passed through a 40°C air blowing tunnel for 30s, and rinsed with water to obtain a high-toughness chlorine-containing copolymer-based filtration membrane.

[0035] Characterization methods of the structure and properties of the high-toughness chlorine-containing copolymer-based filtration membrane:

[0036] Structure and morphology of the membrane: The microstructure of the membrane was observed using a scanning electron microscope (FEI), and the results are shown in Figure 1. Figure 3 .

[0037] Measurement of the properties of the membrane: 1 Tensile test: A high-toughness chlorine-containing copolymer-based filtration membrane was selected and tested for tensile strength and elongation at break using a tensile testing machine, with a total of 10 tests and an average value taken; 2 Flux test: The pure water flux of the membrane was measured under a pressure of 0.1 MPa.

[0038] The membrane-forming solution formula, hollow fiber membrane preparation conditions, and membrane properties are shown in Table 1.

[0039] Table 1

[0040]

[0041]

[0042] Example 2.

[0043] The preparation steps and characterization methods of the structure and properties of the high-toughness chlorine-containing copolymer-based filtration membrane are as described in Example 1:

[0044] The membrane-forming solution formula, hollow fiber membrane preparation conditions, and membrane properties are shown in Table 2.

[0045] Table 2

[0046]

[0047] Example 3.

[0048] The preparation steps and characterization methods of the structure and properties of the high-toughness chlorine-containing copolymer-based filtration membrane are as described in Example 1, and the membrane-forming solution formula, hollow fiber membrane preparation conditions, and membrane properties are shown in Table 3.

[0049] Table 3

[0050]

[0051] Example 4.

[0052] The preparation steps and structure and performance characterization methods of the high-toughness chlorine-containing copolymer-based filter membrane are seen in Example 1. Since the center tube material is a support tube, the tensile test data is the mechanical property of the support tube, so it is not adopted. The membrane liquid formula, and hollow fiber membrane preparation conditions and membrane performance are shown in Table 4.

[0053] Table 4

[0054]

[0055]

[0056] Example 5.

[0057] The preparation steps and structure and performance characterization methods of the high-toughness chlorine-containing copolymer-based filter membrane are seen in Example 1. Since the center tube material is a support tube, the tensile test data is the mechanical property of the support tube, so it is not adopted. The membrane liquid formula, and hollow fiber membrane preparation conditions and membrane performance are shown in Table 5.

[0058] Table 5

[0059]

[0060] Example 6.

[0061] The preparation steps and structure and performance characterization methods of the high-toughness chlorine-containing copolymer-based filter membrane are seen in Example 1. Since the center tube material is a support tube, the tensile test data is the mechanical property of the support tube, so it is not adopted. The membrane liquid formula, and hollow fiber membrane preparation conditions and membrane performance are shown in Table 6.

[0062] Table 6

[0063]

[0064]

[0065] Example 7.

[0066] The preparation steps and structure and performance characterization methods of the high-toughness chlorine-containing copolymer-based filter membrane are seen in Example 1. The membrane liquid formula, and hollow fiber membrane preparation conditions and membrane performance are shown in Table 7.

[0067] Table 7

[0068]

[0069] Example 8.

[0070] The preparation steps and structure and performance characterization methods of the high-toughness chlorine-containing copolymer-based filter membrane are seen in Example 1. The membrane liquid formula, and hollow fiber membrane preparation conditions and membrane performance are shown in Table 8.

[0071] Table 8

[0072]

[0073] Comparative Example 1.

[0074] 1) 300 g of poly (vinyl chloride - butyl acrylate - hydroxyethyl acrylate), 30 g of polyethylene glycol, 5 g of tributyltin chloride were mixed with 665 g of N, N'-dimethylformamide (DMF), and stirred to dissolve at 67°C for 24 h to form a uniform film-forming solution, and vacuum degassed for 2 h;

[0075] 2) Deionized water at 40°C was passed through the center tube of the spinneret, and the film-forming solution of step 1) was extruded from the outer ring of the spinneret to form a tubular liquid film, which passed through an air gap of 10 cm and then vertically entered a coagulation bath at 40°C to solidify into a hollow fiber membrane; after rinsing with water, a high-toughness chlorine-containing copolymer-based filtration membrane was obtained.

[0076] Characterization method of structure and performance of high-toughness chlorine-containing copolymer-based filtration membrane:

[0077] Measurement of membrane performance: 1 Tensile test: select a high-toughness chlorine-containing copolymer-based filtration membrane, and use a tensile testing machine to test the tensile strength and elongation at break, a total of 10 times to take the average value; 2 Flux test, measure the pure water flux of the membrane under 0.1 MPa pressure.

[0078] The film-forming solution formula, hollow fiber membrane preparation conditions and membrane performance are shown in Table 9.

[0079] In comparative example 1, no crosslinking reaction was carried out, and the tensile strength of the obtained membrane was obviously lower than that of example 1, indicating that the crosslinking reaction is very critical and indispensable for maintaining the tensile strength.

[0080] Table 9

[0081]

[0082] Comparative Example 2.

[0083] The preparation steps of PVC filtration membrane and the characterization method of structure and performance are as follows:

[0084] 1) 300 g of poly (vinyl chloride - butyl acrylate - hydroxyethyl acrylate), 30 g of polyethylene glycol, 5 g of tributyltin chloride were mixed with 665 g of N, N'-dimethylformamide (DMF), and stirred to dissolve at 67°C for 24 h to form a uniform film-forming solution, and vacuum degassed for 2 h;

[0085] 2) 40℃ deionized water is passed through the center tube of the spinneret, and the membrane-forming solution of step 1) is extruded from the outer ring of the spinneret to form a tubular liquid film, which is vertically introduced into a 40℃ coagulation bath after passing through an air gap of 10 cm to solidify into a hollow fiber membrane; after rinsing with water, a PVC-based filtration membrane is obtained.

[0086] Characterization method of structure and performance of PVC-based filtration membrane:

[0087] Determination of membrane performance: 1 Tensile test: select a PVC-based filtration membrane, and use a tensile testing machine to test the tensile strength and elongation at break, a total of 10 times to take the average value; 2 Flux test, determine the pure water flux of the membrane under 0.1 MPa pressure.

[0088] The membrane-forming solution formula, hollow fiber membrane preparation conditions and membrane performance are shown in Table 10.

[0089] The elongation at break and flux of the membrane obtained by using PVC as the membrane substrate in Comparative Example 2 are obviously lower than those of Example 1, which indicates that the vinyl chloride-acrylate copolymer in the present application plays a key toughening role, and also plays an indispensable role in forming a loose pore structure.

[0090] Table 10

[0091]

[0092] The above-described examples only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as limiting the scope of the patent of the present application. For ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A process for the preparation of high tenacity chlorine containing copolymer based filtration membranes, characterized by It has the following steps: 1) mixing vinyl chloride-acrylate copolymer with weight percentage of 20-40%, pore size regulator with weight percentage of 1-5%, thermal stabilizer with weight percentage of 0.1-1% and solvent with weight percentage of 55-75%, stirring and dissolving into uniform membrane forming solution at 50-70℃; the pore size regulator is polyvinylpyrrolidone, polyethylene glycol or glycerol; the vinyl chloride-acrylate copolymer is one or more of poly(vinyl chloride-butyl acrylate-hydroxyethyl acrylate), poly(vinyl chloride-hexyl acrylate-hydroxyethyl acrylate), poly(vinyl chloride-octyl acrylate-hydroxyethyl acrylate), poly(vinyl chloride-butyl acrylate-hydroxypropyl acrylate), poly(vinyl chloride-hexyl acrylate-hydroxypropyl acrylate) or poly(vinyl chloride-octyl acrylate-hydroxypropyl acrylate); 2) extruding the membrane forming solution from the spinneret to form tubular liquid membrane, uniformly wrapping around the substance in the spinneret center tube, the liquid membrane vertically enters the coagulation bath to solidify into hollow fiber membrane after passing through 0-20cm air gap; the substance in the spinneret center tube is deionized water or support tube; 3) the hollow fiber membrane obtained by solidifying in the coagulation bath in step 2) is blown dry on the membrane surface by passing through 40-55℃ air blowing tunnel for 30-60s, then immersed in pyromellitic dianhydride solution, continues to pass through 40-55℃ air blowing tunnel for 10-30s, then rinsed with water to obtain high-toughness chlorine-containing copolymer-based filtration membrane.

2. The process for the preparation of high toughness chlorine-containing copolymer-based filtration membranes according to claim 1, characterized in that, the monomer composition of the vinyl chloride-acrylate copolymer is: vinyl chloride with weight percentage of 50-80%, acrylate with 15-40% and hydroxyalkyl acrylate with 3-10%; the acrylate is butyl acrylate, hexyl acrylate or octyl acrylate; the hydroxyalkyl acrylate is hydroxyethyl acrylate or hydroxypropyl acrylate.

3. The method for preparing the high-toughness chlorine-containing copolymer-based filter membrane according to claim 1, characterized in that, the number average molecular weight of the vinyl chloride-acrylate copolymer is 40,000-100,000Da.

4. The method for preparing the high-toughness chlorine-containing copolymer-based filter membrane according to claim 1, characterized in that, the thermal stabilizer is zinc stearate, calcium stearate, tributyltin chloride, dibutyltin diacetate, dibutyltin maleate, dimethyltin mercaptide, dibutyltin dilaurate or di-n-octyltin dilaurate; the solvent is N,N'-dimethylformamide, N,N'-dimethylacetamide or N-methylpyrrolidone; the support tube is polymeric fiber braided tube, and the material of the support tube is polyethylene terephthalate, polytrimethylene terephthalate or aramid.

5. The method for preparing the high-toughness chlorine-containing copolymer-based filter membrane according to claim 1, characterized in that, the composition of the pyromellitic dianhydride solution is: pyromellitic dianhydride with weight percentage of 30-60% and solvent with weight percentage of 40-70%; the solvent in the pyromellitic dianhydride solution is N,N'-dimethylformamide, N,N'-dimethylacetamide or N-methylpyrrolidone.

6. The method for preparing the high-toughness chlorine-containing copolymer-based filter membrane according to claim 1, characterized in that, when the hollow fiber membrane is immersed in the pyromellitic dianhydride solution, the contact time with the pyromellitic dianhydride solution is 1-5s.

7. The high-toughness chlorine-containing copolymer-based filtration membrane prepared by the method of any one of claims 1-6.

8. The high-toughness, chlorine-containing copolymer-based filtration membrane according to claim 7, characterized in that, The high-toughness chlorine-containing copolymer-based filter membrane has the weight percentage of 95-99.5% of chloroethylene-acrylate copolymer and the weight percentage of 0.5-5% of cross-linking product of chloroethylene-acrylate copolymer, and the cross-linking product of chloroethylene-acrylate copolymer is the product after the reaction of chloroethylene-acrylate copolymer and pyromellitic dianhydride.

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