Solvent-resistant filter membrane and application thereof in butadiene rubber solution polymerization gel reduction process

Abstract

The invention discloses a solvent-resistant filter membrane and application of the solvent-resistant filter membrane in a butadiene rubber solution polymerization gel reduction process, and belongs to the field of high polymer material technologies and chemical separation. The filter membrane comprises a pretreated non-woven fabric, a polyetherimide base layer and a polyimide selection layer from bottom to top, the preparation method comprises the steps of raw material pretreatment, polyetherimide base layer preparation, polyimide selection layer in-situ generation and post-treatment, and performance optimization is realized through aminolysis ring-opening crosslinking, interfacial polymerization doping of perfluorodecanethiol, cyclohexane pre-expansion and trifluoroacetic anhydride post-treatment. The method is applied to multiple nodes in a butadiene rubber solution polymerization process. The stable filter membrane structure is constructed through a multi-dimensional innovative means, the problems that a traditional filter membrane is insufficient in solvent resistance, prone to interlayer stripping, poor in pollution resistance and the like are solved, efficient interception of gel particles and catalyst residues is achieved, the gel content of rubber is remarkably reduced, long-term operation is stable, and strict process requirements are met.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of high polymer materials and chemical separation, and in particular to a solvent-resistant filter membrane and application of the solvent-resistant filter membrane in a butadiene rubber solution polymerization gel reduction process. BACKGROUND

[0002] Butadiene rubber is an important synthetic rubber, and a solution polymerization process thereof is usually carried out in an organic solvent such as hexane or benzene under the action of an aluminum alkyl-nickel catalyst. In the polymerization process, catalyst impurities and polymerization by-products are prone to form gel particles, which leads to the decline of the performance of rubber products, the blockage of production equipment, and the reduction of production efficiency and product qualification rate, and therefore, a special filter membrane resistant to cyclohexane and other polymerization solvents is required to remove the gel.

[0003] Existing solutions mainly use traditional polymer filter membranes such as polyamide and polyvinylidene fluoride, or improve the solvent resistance through simple cross-linking modification, and some solutions attempt to build a dense selection layer on the surface of the support layer to strengthen the interception effect.

[0004] However, the existing technology has obvious deficiencies: the traditional filter membrane is prone to swelling and dissolving in strong polar organic solvents, and has poor long-term running stability; single cross-linking modification cannot balance the solvent resistance and permeation flux, and is prone to the seesaw effect; the filter membrane has poor compatibility with the polymerization system, and the surface is prone to adsorbing rubber segments to cause pollution and blockage; the support layer and the selection layer have weak bonding force and are prone to delamination and falling off; and the pore size distribution is wide, which cannot accurately intercept gel particles, and cannot meet the stringent requirements of the butadiene rubber polymerization process. SUMMARY

[0005] The solvent-resistant filter membrane and the application thereof in the butadiene rubber solution polymerization gel reduction process are proposed to solve the problems in the prior art.

[0006] To achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0007] The preparation method of the solvent-resistant filter membrane comprises the following steps:

[0008] S1, raw material pretreatment:

[0009] The non-woven fabric is immersed in a 5-10wt% polyvinyl alcohol solution for 5-15min, the liquid amount is controlled by a precision roller, and the non-woven fabric is dried in an oven at 80-100 DEG C for 5-10min; the polyetherimide resin is crushed and sieved, and washed with anhydrous ethanol three times and dried;

[0010] After the non-woven fabric is immersed in the polyvinyl alcohol solution, the polyvinyl alcohol molecular chain is firmly adsorbed on the fiber surface through hydrogen bond and Van der Waals force, the precision roller controls the liquid amount to ensure that the formed polyvinyl alcohol modified layer is thin and uniform, and the over-blocking of the large pore structure of the non-woven fabric itself is avoided, and then dried at 80-100℃, not only removes the water, but also induces the crystallization and physical crosslinking of the polyvinyl alcohol molecular chain, thereby forming a firm and hydrophilic transition layer on the non-woven fabric fiber; the role of this layer of polyvinyl alcohol is dual: first, it greatly improves the compatibility of the non-woven fabric with the subsequent polyetherimide casting solution, the hydroxyl group on the polyvinyl alcohol has good interaction with the solvent and polyetherimide, so that the polyetherimide base layer can be firmly anchored on the non-woven fabric, preventing interlayer peeling in the organic solvent environment; second, it effectively flattens the rough and uneven surface of the non-woven fabric, providing an ideal substrate for scraping a layer of ultra-thin, defect-free polyetherimide resin base layer;

[0011] The polyetherimide resin is broken and sieved to a specific particle size, in order to obtain the maximum and uniform specific surface area during dissolution, ensuring that the polyetherimide particles can be dissolved quickly and synchronously, forming a uniform casting solution without undissolved particles, which is the premise of obtaining a uniform base layer; the purpose of washing with anhydrous ethanol is to act as a mild Soxhlet extraction, aimed at removing the catalyst, low molecular weight oligomers and other small molecule additives remaining in the resin during synthesis and granulation. If these impurities are not removed, they will become uncontrollable pore-forming sites or defect sources during phase inversion, seriously weakening the mechanical integrity of the base layer, and causing the membrane structure to collapse due to the dissolution of impurities during long-term solvent resistance testing;

[0012] The above pretreatment, by enhancing the interfacial bonding force, improving the flatness of the substrate, ensuring the purity and uniformity of the raw material, together gives the filter membrane excellent solvent resistance, builds a firm and defect-free bottom structure that can resist the long-term erosion and swelling stress of alkanes, aromatic hydrocarbons and other polymerization solvents, providing the most reliable skeletal support for the upper precise polyimide selection layer. In the butadiene rubber solution polymerization gel reduction process, this stability directly translates into persistent separation precision and ultra-long service life; the pretreatment prevents interlayer peeling and structural degradation, ensuring that the retention rate of the filter membrane for catalyst fragments and gel particles remains stable; at the same time, pure raw materials avoid secondary pollution of the polymerization system caused by the dissolution of impurities in the membrane itself;

[0013] S2, preparation of the polyetherimide base layer:

[0014] The pretreated polyetherimide resin, polyethylene glycol, nano-SiO2 and N,N-dimethylacetamide were mixed, stirred at 80 °C for 6 h, vacuum degassed for 12 h, scraped on a non-woven fabric support by a film scraper, soaked in a 18 °C pure water coagulation bath for 24 h, then soaked in a 70 °C 5 wt% ethanol solution of 1,6-hexanediamine for 4 h, washed with ethanol and water for 3 times, and vacuum dried at 130 °C for 12 h;

[0015] The casting solution preparation and degassing are the foundation of the microstructure: the pretreated polyetherimide resin, pore-forming agent polyethylene glycol, nano-SiO2 and solvent N,N-dimethylacetamide are mixed to form a thermodynamically uniform solution at 80 °C. In this system, the solvent is dissolved, and the polyethylene glycol is a hydrophilic polymer that forms a homogeneous system with the polyetherimide resin / solvent, but its affinity with water is much stronger than that of the polyetherimide resin, and the nano-SiO2 is uniformly dispersed therein as an inorganic filler. Subsequent vacuum degassing is crucial, which removes the gas entrained during stirring and prevents the formation of macroscopic defects such as pinholes in the subsequent film formation;

[0016] The film scraping and phase inversion are a dynamic process of forming a porous structure: after the casting solution is scraped on the pretreated non-woven fabric, it is immediately immersed in an 18 °C pure water coagulation bath. At this time, rapid bidirectional diffusion occurs between the solvent and water, water invades the casting solution, and the solvent escapes from the casting solution. This exchange causes the originally uniform casting solution to undergo liquid-liquid phase separation into a polyetherimide resin-rich phase and a polyetherimide resin-lean phase. The rich phase will form the film skeleton, and the lean phase will form the pore channel. The presence of polyethylene glycol exacerbates this phase separation and, due to its hydrophilicity, rapidly migrates to the water phase under the action of water, leaving additional holes. At the same time, nano-SiO2 is fixed by the solidified polyetherimide resin skeleton, playing a role in physical reinforcement and regulating the pore structure. Finally, the polyetherimide resin-rich phase solidifies to form an initial base film with a large finger-shaped pore in the bottom layer and a microporous surface layer;

[0017] Then, chemical crosslinking is a decisive step to give the base layer excellent solvent resistance: the phase-inverted base film is immersed in an ethanol solution of 1,6-hexanediamine and heated, and a key aminolysis ring-opening crosslinking reaction occurs. The nitrogen atom on a primary amino group acts as a nucleophile to attack a carbonyl carbon atom on the imide ring, causing the bond between the carbonyl carbon and nitrogen to break, the imide ring to open, and the crosslinking agent molecule to be connected to the polyetherimide chain through the newly formed amide bond. At the same time, a negative charge is generated on the original imide nitrogen atom, which acquires a proton from the solvent or system to form an amide group with the original carbon-oxygen double bond. The primary amino group of ethylenediamine has high reactivity and can undergo ring-opening reaction with another polyetherimide five-membered ring to covalently connect different polyetherimide molecular chains;

[0018]

[0019] The above cross-linking reaction initially creates a three-dimensional network structure, greatly limiting the free movement of polyetherimide molecular chains in organic solvents, thereby fundamentally inhibiting the swelling phenomenon, and converting the base film from a material that can be partially dissolved or severely swollen by strong solvents into a solvent-resistant skeleton that is dimensionally stable in alkanes and aromatic hydrocarbons and has a very high mechanical strength retention rate. Finally, the washing and drying steps are aimed at thoroughly removing residual porogens, unreacted cross-linking agents, and by-products from the system, ensuring the purity and long-term stability of the film, and vacuum drying at 130°C further promotes the completion of the cross-linking reaction and removes moisture, allowing the film structure to be finalized;

[0020] S3. Preparation of the polyimide selective layer:

[0021] Mix m-phenylenediamine and tris(2-aminoethyl)amine with deionized water to prepare an aqueous phase, mix m-phenyltricarbonyl chloride and perfluorodecanethiol with n-hexane to prepare an oil phase, fix the base film, pour the aqueous phase solution, and stand for 3 minutes to absorb. Remove excess liquid with a rubber roller, pour an equal volume of oil phase solution, and after 60 seconds of reaction, drain the solution. Transfer the wet film to a vacuum oven at 110°C and heat treat for 20 minutes. Rinse with n-hexane and ethanol, and vacuum dry at 70°C for 4 hours to complete the preparation of the polyimide selective layer.

[0022] The preparation and absorption of the aqueous and oil phases are the prerequisites for forming the separation layer: dissolve m-phenylenediamine and tris(2-aminoethyl)amine in water, and use them as the aqueous phase monomers. When the aqueous phase solution comes into contact with the hydrophilic base film, these amine monomers are absorbed and fill the surface micropores of the base film through capillary force and hydrogen bonding. Subsequently, remove the excess liquid with a rubber roller to accurately control the position of the interfacial reaction, prevent bulk polymerization in the aqueous liquid layer, and ensure the formation of an ultrathin separation layer.

[0023] When the oil phase containing m-phenyltricarbonyl chloride and perfluorodecanethiol is poured in, the reaction occurs instantaneously at the oil-water interface. The m-phenyltricarbonyl chloride dissolved in n-hexane rapidly diffuses to the interface and undergoes a Schotten-Baumann reaction with the amine monomers absorbed on the surface of the base film. The amine monomers in the aqueous phase have a pair of lone pair electrons on the nitrogen atom, acting as a powerful nucleophile, attacking the carbonyl carbon atom in the acyl chloride molecule in the oil phase. This carbonyl carbon, due to the strong electronegativity of the oxygen and chlorine atoms attached to it, exhibits significant positive charge and is highly susceptible to nucleophilic attack. The resulting negatively charged tetrahedral intermediate is very unstable and rapidly eliminates a chloride ion, rehybridizing to form a more stable carbon-oxygen double bond (C=O). Ultimately, the amine molecule is covalently linked to the acyl chloride molecule through the newly formed amide bond (-CO-NH-), forming a polyamide film.

[0024]

[0025] Meanwhile, the terminal thiol group of the perfluorodecanethiol in the oil phase reacts with the unreacted acyl chloride groups in the polyamide network, and the sulfur atom in the thiol molecule, due to its lone pair of electrons, attacks the partially positively charged carbonyl carbon atom in the acyl chloride functional group, and the unstable tetrahedral intermediate rapidly eliminates one molecule of hydrogen chloride to form a stable thioester bond, thereby firmly anchoring the long-chain perfluoroalkyl group at the surface and orifice of the separation layer;

[0026]

[0027] The thermal treatment imidization is a key post-curing step, the wet film is heat treated at 110°C under vacuum to promote the completion of the crosslinking reaction, and the separation layer network is more dense, and the flushing and drying aim to completely remove the unreacted monomers, by-products hydrochloric acid and physically adsorbed impurities, and obtain a pure and stable final product;

[0028] S4, post-treatment:

[0029] After the in-situ generation of the polyimide selective layer on the polyetherimide base layer, it is placed in cyclohexane for 48-72h, during which time a small amount of trifluoroacetic anhydride is added, washed with ethanol, and vacuum dried for 12h, and then hot pressed for 30s on a flat plate hot press to calibrate the pore size, to obtain the finished filter membrane;

[0030] The composite membrane is immersed in cyclohexane, which has the primary functions of solvent pre-expansion and activation: as a true solvent for the polymerization process, cyclohexane can make the newly generated polyimide selective layer molecular chain segments relax and swell moderately, so that it reaches a thermodynamic stable state before being put into use, avoiding performance fluctuations during operation, and the trifluoroacetic anhydride added in portions during this period will dissolve in cyclohexane and diffuse into the swollen polymer network, and the trifluoroacetic anhydride, as a highly efficient acylating agent and dehydrating agent, can react with the residual amide groups or terminal amino groups in the selective layer polymer. The reaction with the amino group is the most important, which can generate a more stable and more hydrophobic trifluoroacetyl group, while removing the polar sites that can form hydrogen bonds;

[0031]

[0032] This process optimizes the chemical structure of the separation layer at the molecular scale, on the one hand, by introducing a large number of trifluoromethyl groups, it significantly improves the crosslinking density and hydrophobicity of the separation layer, thereby making its solvent resistance leap in quality; on the other hand, it reduces the chemical polarity of the membrane surface, which can effectively reduce the adsorption of butadiene rubber molecular chains, and endow the membrane with essential anti-pollution properties;

[0033] Ethanol washing and vacuum drying are aimed at completely terminating the reaction and removing residual reaction by-products and solvents, ensuring the purity and structural stability of the membrane. Finally, by flat-plate hot pressing, the selective layer of polyimide is subjected to a small amount of thermoplastic deformation at a temperature higher than the glass transition temperature but lower than the melting point of the polymer, effectively shrinking the oversized or loosely structured pores formed during interfacial polymerization, making the pore size distribution of the entire separation layer more narrow and uniform, thereby ensuring more accurate and reliable retention accuracy for gel particles and catalyst agglomerates.

[0034] Preferably, the polyetherimide base layer has a thickness of 30-50 μm, the polyimide selective layer has a thickness of 0.1-0.5 μm, and the finished filter membrane has a thickness of 130-250 μm and a pore size of 30-500 nm.

[0035] Preferably, the solvent-resistant filter membrane is used to filter materials at one or more of the following process nodes:

[0036] After the catalyst is prepared and before it enters the aging tank;

[0037] After the catalyst is aged and before it enters the polymerization kettle;

[0038] After the polymerization reaction and before the dope enters the subsequent processing unit.

[0039] The solvent-resistant filter membrane prepared by the preparation method of the present application is used after the catalyst is prepared and aged and after the polymerization reaction in the solution polymerization process of butadiene rubber, effectively retaining micrometer-sized gel particles and nanometer-sized catalyst residues in the solution, so that the purified polymerization liquid enters the subsequent section, thereby significantly reducing the gel content in the final product from the source and effectively eliminating the "fish eye" defect. At the same time, its excellent solvent resistance and anti-pollution ensure the stability and high throughput in the environment of strong organic solvents such as cyclohexane for a long time.

[0040] Compared with the prior art, the present application has the following advantages:

[0041] 1. The present application innovatively uses hexanediamine ethanol solution to chemically cross-link the polyetherimide base layer, and cooperates with the imide ring opening covalent connection mechanism to break through the limitation of insufficient solvent resistance of the traditional base layer. The primary amino group of hexanediamine attacks the imide ring carbonyl group as a nucleophile, covalently connecting different polyetherimide molecular chains through amide bonds to form a stable three-dimensional network, greatly limiting the free movement of molecular chains and fundamentally inhibiting solvent swelling. At the same time, nano-SiO2 and polyethylene glycol in the casting solution synergistically control the pore structure, taking into account mechanical strength and permeation flux, so that the base layer remains dimensionally stable and structurally intact in alkanes and aromatic hydrocarbon solvents for a long time.

[0042] 2、The application introduces perfluorodecanethiol in the oil phase, cooperates with the Schotten-Baumann reaction and the anchoring mechanism of the thioester bond, solves the problem of poor pollution resistance of the traditional selective layer, and realizes efficient interception of gel particles and catalyst residues.

[0043] 3、The application innovatively adopts cyclohexane pre-expansion combined with trace trifluoroacetic anhydride post-treatment, cooperates with the molecular chain relaxation and acylation modification mechanism, realizes synchronous improvement of solvent resistance and interception precision. The cyclohexane pre-expansion makes the molecular chain of the selective layer reach a thermodynamic stable state, avoids performance fluctuation in operation; the trifluoroacetic anhydride as an acylation reagent reacts with residual amino groups to generate a more hydrophobic trifluoroacetyl group, improves the crosslinking density and solvent resistance, and at the same time reduces the surface polarity to enhance the pollution resistance. Subsequent flat plate hot pressing calibrates the aperture, so that the aperture is concentrated in 30-500nm, ensures the interception precision accurate and reliable, and perfectly adapts to the butadiene rubber gel reduction process requirements. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 A schematic diagram of the solvent-resistant filter membrane produced by the application;

[0045] Figure 2 A nuclear magnetic resonance spectrum of the polyetherimide crosslinked by 1,6-hexanediamine. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments.

[0047] Embodiment 1: The preparation method of the solvent-resistant filter membrane, comprising the following steps:

[0048] S1, raw material pretreatment:

[0049] The non-woven fabric is immersed in a 7wt% polyvinyl alcohol solution for 5-15min, the liquid amount is controlled by a precision roller, dried in an oven at 90℃ for 5-10min, the polyetherimide resin is broken and sieved, washed with anhydrous ethanol three times, and dried;

[0050] S2, preparation of the polyetherimide base layer:

[0051] The pretreated polyetherimide resin, polyethylene glycol, nano-SiO2 and N,N-dimethylacetamide were mixed in a mass ratio of 20:25:2:50, stirred at 80°C for 6h, vacuum degassed for 12h, scraped on a non-woven fabric support by using a film scraper, soaked in a 18°C pure water coagulation bath for 24h, then soaked in a 70°C 5wt% ethanol solution of 1,6-hexanediamine for 4h, washed with ethanol and water for 3 times, and vacuum dried at 130°C for 12h;

[0052] S3, preparation of the polyimide selection layer:

[0053] The m-phenylenediamine and tri(2-aminoethyl)amine were mixed with deionized water to prepare an aqueous phase, the mass fraction of m-phenylenediamine was 1.5wt%, and the mass fraction of tri(2-aminoethyl)amine was 0.5wt%. The m-phenyltricarbonyl chloride, perfluorodecanethiol and n-hexane were mixed to prepare an oil phase, the mass fraction of m-phenyltricarbonyl chloride was 1.0wt%, and the mass fraction of perfluorodecanethiol was 0.015wt%. The base film was fixed, the aqueous phase solution was poured, and was adsorbed for 3min. The excess liquid was removed by using a rubber roller. An equal volume of the oil phase solution was poured, reacted for 60s, and then was discharged. The wet film was transferred to a vacuum oven at 110°C, and was heat treated for 20min. The n-hexane and ethanol were washed, and the vacuum drying was performed at 70°C for 4h. The preparation of the polyimide selection layer was completed.

[0054] S4, post-treatment:

[0055] After the polyimide selection layer was generated in situ on the polyetherimide base layer, the polyimide selection layer was immersed in cyclohexane for 48-72h, during which a small amount of trifluoroacetic anhydride was added in several times, washed with ethanol, and vacuum dried for 12h. The pore size was calibrated by hot pressing for 30s by using a flat plate hot press, and a finished filter membrane was obtained.

[0056] Example 2: a preparation method of a solvent-resistant filter membrane, including the following steps:

[0057] S1, pretreatment of raw materials:

[0058] The non-woven fabric was immersed in a 7wt% polyvinyl alcohol solution for 5-15min, the liquid amount was controlled by using a precision roller, and the non-woven fabric was dried in an oven at 90°C for 5-10min. The polyetherimide resin was broken and sieved, and washed with anhydrous ethanol for 3 times, and dried.

[0059] S2, preparation of the polyetherimide base layer:

[0060] The pretreated polyetherimide resin, polyethylene glycol, nano-SiO2 and N,N-dimethylacetamide were mixed in a mass ratio of 30:25:2:50, stirred at 80°C for 6h, vacuum degassed for 12h, scraped on a non-woven fabric support by using a film scraper, soaked in a 18°C pure water coagulation bath for 24h, then soaked in a 70°C 5wt% ethanol solution of 1,6-hexanediamine for 4h, washed with ethanol and water for 3 times, and vacuum dried at 130°C for 12h.

[0061] S3, Preparation of polyimide selection layer:

[0062] Mix m-phenylenediamine and tris(2-aminoethyl)amine with deionized water to prepare an aqueous phase, the mass fraction of m-phenylenediamine is 1.5wt%, and the mass fraction of tris(2-aminoethyl)amine is 0.5wt%. Mix m-benzene tricarboxylic acid chloride and perfluorodecanethiol with n-hexane to prepare an oil phase, the mass fraction of m-benzene tricarboxylic acid chloride is 1.0wt%, and the mass fraction of perfluorodecanethiol is 0.015wt%. Pour the aqueous phase solution into the base film, and stand for 3min. Remove the excess liquid with a rubber roller. Pour an equal volume of the oil phase solution, and discharge after 60s of reaction. Transfer the wet film to a vacuum oven at 110°C, and heat treat for 20min. Rinse with n-hexane and ethanol, and vacuum dry at 70°C for 4h. The preparation of the polyimide selection layer is completed.

[0063] S4, Post-processing:

[0064] After generating the polyimide selection layer in situ on the polyetherimide base layer, immerse it in cyclohexane for 48-72h, and add a small amount of trifluoroacetic anhydride in several times during the period. Wash with ethanol, and vacuum dry for 12h. Calibrate the pore size by hot pressing for 30s with a flat plate hot press, to obtain the finished filter membrane.

[0065] Example 3: Preparation method of solvent-resistant filter membrane, comprising the following steps:

[0066] S1, Raw material pretreatment:

[0067] Immerse the non-woven fabric in a 7wt% polyvinyl alcohol solution for 5-15min, control the liquid amount with a precision roller, and dry in an oven at 90°C for 5-10min. Crush and sieve the polyetherimide resin, and wash with anhydrous ethanol three times, and dry.

[0068] S2, Preparation of polyetherimide base layer:

[0069] Mix the pretreated polyetherimide resin, polyethylene glycol, nano-SiO2, and N,N-dimethylacetamide at a mass ratio of 25:25:2:50, and stir at 80°C for 6h. Vacuum degassing for 12h, use a film scraper to scrape a film on the non-woven fabric support, immerse in a 18°C pure water coagulation bath for 24h, and then immerse in a 70°C 1,6-hexanediamine 5wt% ethanol solution for 4h. Wash with ethanol and water three times, and vacuum dry at 130°C for 12h.

[0070] S3, Preparation of polyimide selection layer:

[0071] The water phase is prepared by mixing m-phenylenediamine, tris(2-aminoethyl)amine and deionized water, the mass fraction of m-phenylenediamine is 1.5 wt%, the mass fraction of tris(2-aminoethyl)amine is 0.5 wt%, the oil phase is prepared by mixing m-phenyltricarbonyl chloride and perfluorodecanethiol with n-hexane, the mass fraction of m-phenyltricarbonyl chloride is 1.0 wt%, the mass fraction of perfluorodecanethiol is 0.015 wt%, the base film is fixed, the water phase solution is poured, and the excess liquid is removed by a rubber roller after standing and adsorbing for 3 min, an equal volume of oil phase solution is poured, the reaction is carried out for 60 s, then the wet film is transferred to a vacuum oven at 110°C for heat treatment for 20 min, n-hexane and ethanol are used for washing, and vacuum drying is carried out at 70°C for 4 h, so that the preparation of the polyimide selective layer is completed;

[0072] S4, post-treatment:

[0073] After the polyimide selective layer is generated in situ on the polyetherimide base layer, the polyimide selective layer is immersed in cyclohexane for 48-72 h, during which time a small amount of trifluoroacetic anhydride is added in several portions, washed with ethanol, and vacuum dried for 12 h, and then the pore size is calibrated by hot pressing for 30 s using a flat plate hot press, so that the finished filter membrane is obtained.

[0074] Example 4: a preparation method of a solvent-resistant filter membrane, comprising the following steps:

[0075] S1, raw material pretreatment:

[0076] The non-woven fabric is immersed in a 7 wt% polyvinyl alcohol solution for 5-15 min, the liquid amount is controlled by a precision roller, and the non-woven fabric is dried in an oven at 90°C for 5-10 min, the polyetherimide resin is broken and sieved, and washed with anhydrous ethanol three times and dried;

[0077] S2, preparation of a polyetherimide base layer:

[0078] The pretreated polyetherimide resin, polyethylene glycol, nano-SiO2 and N,N-dimethylacetamide are mixed in a mass ratio of 25:25:2:50, stirred at 80°C for 6 h, vacuum degassed for 12 h, and then coated on the non-woven fabric support using a film scraper, immersed in a 18°C pure water coagulation bath for 24 h, and then immersed in a 70°C 1,6-hexanediamine 5 wt% ethanol solution for 4 h, washed with ethanol and water three times, and vacuum dried at 130°C for 12 h;

[0079] S3, preparation of a polyimide selective layer:

[0080] The water phase is prepared by mixing m-phenylenediamine, tris(2-aminoethyl)amine and deionized water, the mass fraction of m-phenylenediamine is 1.5 wt%, and the mass fraction of tris(2-aminoethyl)amine is 0.5 wt%. The oil phase is prepared by mixing m-phenyltricarbonyl chloride, perfluorodecanethiol and n-hexane, the mass fraction of m-phenyltricarbonyl chloride is 0.8 wt%, and the mass fraction of perfluorodecanethiol is 0.015 wt%. The base film is fixed, the water phase solution is poured, and the solution is adsorbed for 3 min. The excess liquid is removed by a rubber roller. The same volume of oil phase solution is poured, and the solution is discharged after 60 s of reaction. The wet film is transferred to a vacuum oven at 110°C for heat treatment for 20 min. The n-hexane and ethanol are washed, and the vacuum drying is performed at 70°C for 4 h. The preparation of the polyimide selective layer is completed.

[0081] S4, post-treatment:

[0082] After the polyimide selective layer is generated in situ on the polyetherimide base layer, the polyimide selective layer is immersed in cyclohexane for 48-72 h, and a small amount of trifluoroacetic anhydride is added several times during the immersion. The ethanol is washed, and the vacuum drying is performed for 12 h. The pore size is calibrated by hot pressing for 30 s by a flat plate hot press. The finished filter membrane is obtained.

[0083] Example 5: a preparation method of a solvent-resistant filter membrane, including the following steps:

[0084] S1, raw material pretreatment:

[0085] The non-woven fabric is immersed in a 7 wt% polyvinyl alcohol solution for 5-15 min, the liquid amount is controlled by a precision roller, and the non-woven fabric is dried in an oven at 90°C for 5-10 min. The polyetherimide resin is broken and sieved, and washed with anhydrous ethanol three times and dried.

[0086] S2, preparation of a polyetherimide base layer:

[0087] The pretreated polyetherimide resin, polyethylene glycol, nano-SiO2 and N,N-dimethylacetamide are mixed in a mass ratio of 25:25:2:50, stirred at 80°C for 6 h, vacuum degassed for 12 h, and coated on a non-woven fabric support by a film coating machine. The non-woven fabric is immersed in a pure water coagulation bath at 18°C for 24 h, and then immersed in a 5 wt% ethanol solution of 1,6-hexanediamine at 70°C for 4 h. The non-woven fabric is washed with ethanol and water three times, and vacuum dried at 130°C for 12 h.

[0088] S3, preparation of a polyimide selective layer:

[0089] The water phase is prepared by mixing m-phenylenediamine, tris(2-aminoethyl)amine and deionized water, the mass fraction of m-phenylenediamine is 1.5 wt%, the mass fraction of tris(2-aminoethyl)amine is 0.5 wt%, the oil phase is prepared by mixing m-phenyltricarbonyl chloride, perfluorodecanethiol and n-hexane, the mass fraction of m-phenyltricarbonyl chloride is 1.2 wt%, the mass fraction of perfluorodecanethiol is 0.015 wt%, the base film is fixed, the water phase solution is poured, and the solution is adsorbed for 3 min, the excess liquid is removed by a rubber roller, an equal volume of oil phase solution is poured, the reaction is carried out for 60 s, then the wet film is transferred to a vacuum oven at 110°C, and the film is heat treated for 20 min, then the film is washed with n-hexane and ethanol, and vacuum dried at 70°C for 4 h, thereby completing the preparation of the polyimide selective layer;

[0090] S4, post-treatment:

[0091] After the polyimide selective layer is generated in situ on the polyetherimide base layer, the layer is immersed in cyclohexane for 48-72 h, during which time a small amount of trifluoroacetic anhydride is added in portions, the layer is washed with ethanol, and vacuum dried for 12 h, then the layer is heat pressed for 30 s by a flat plate heat press to calibrate the pore size, thereby obtaining the finished filter membrane.

[0092] Comparative Example 1

[0093] In Comparative Example 1, the mass ratio of the polyetherimide resin, polyethylene glycol, nano-SiO2 and N,N-dimethylacetamide is 35:25:2:50, as compared with Example 3.

[0094] Comparative Example 2

[0095] In Comparative Example 2, the mass fraction of m-phenyltricarbonyl chloride is 0.5 wt%, as compared with Example 3.

[0096] Comparative Example 3

[0097] In Comparative Example 3, the non-woven fabric is not treated with polyvinyl alcohol solution, as compared with Example 3.

[0098] Comparative Example 4

[0099] In Comparative Example 4, the nano-SiO2 is not added to the polyetherimide base layer, as compared with Example 3.

[0100] Comparative Example 5

[0101] In Comparative Example 5, the perfluorodecanethiol is not added to the oil phase, as compared with Example 3.

[0102] Comparative Example 6

[0103] In Comparative Example 6, the trifluoroacetic anhydride is not added to the cyclohexane treated filter membrane, as compared with Example 3.

[0104] Comparative Example 7

[0105] In comparison with Example 3, no preliminary crosslinking with 1,6-ethylenediamine was performed when preparing the polyetherimide-based layer in Comparative Example 7.

[0106] Performance test:

[0107] According to the standard test methods in the national standards such as GB / T 1690-2010 "Vulcanized Rubber Resistance to Liquid Test", GB / T 32361-2015 "Separation Membrane Pore Size Test Method Bubble Point and Average Flow Rate Method", GB / T 36138-2018 "Polytetrafluoroethylene Flat Plate Microfiltration Membrane for Bacteria Removal", GB / T 1040.2-2022 "Determination of Tensile Properties of Plastics", GB / T 6165-2021 "Performance Test of High Efficiency Air Filter", etc., the weight loss, size change rate, bubble point pressure, average pore size, tensile strain, tensile strength, elongation at break and pressure drop and filtration efficiency repeatability of the filter membranes prepared in the above examples and comparative examples were tested after immersion.

[0108] Table 1 Mechanical test data of filter membranes prepared in each group

[0109]

[0110] Table 2 Performance test data of filter membranes prepared in each group

[0111]

[0112] Data analysis:

[0113] Figure 1 The schematic diagram of the solvent-resistant filter membrane produced by the present application is shown in FIG. 1. The solvent-resistant filter membrane has a unique three-layer gradient structure, which is composed of a polyimide selection layer, a polyetherimide-based layer and a pretreated non-woven fabric from top to bottom. The surface of the polyimide selection layer is grafted with perfluoroalkyl molecular brushes, which endows the layer with excellent anti-pollution properties. The polyetherimide-based layer in the middle layer serves as a skeleton and forms a solvent-resistant composite structure through chemical crosslinking, ensuring high flux through asymmetric pores (finger-shaped pores and surface micropores). The bottom layer of the pretreated non-woven fabric is firmly combined through interfacial modification to prevent interlayer peeling under solvent impact. When the solution containing gel butadiene rubber flows through the membrane surface, micron-sized gel particles are precisely intercepted by the selection layer, and the purified solution smoothly passes through the porous structure, finally achieving efficient gel reduction.

[0114] Figure 2The aromatic hydrogen peak of 7.0-8.0ppm in the nuclear magnetic resonance hydrogen spectrum of the polyetherimide crosslinked by 1,6-hexanediamine indicates that the polyetherimide aromatic ring skeleton is not destroyed after crosslinking by 1,6-hexanediamine, the aliphatic hydrogen peak of 1.0-4.0ppm corresponds to the characteristic signal of the hexanediamine segment, confirming that it successfully participates in the crosslinking reaction and forms a three-dimensional network, and there is no obvious impurity peak in each peak, indicating that the product has high purity and the crosslinking process is effective, and the polyetherimide base layer is endowed with stable solvent-resistant structure.

[0115] According to the data shown in Table 1 and Table 2, the solvent resistance, mechanical properties and filtration stability of Example 1 are slightly inferior to those of Example 3, and the core reason lies in the difference in the raw material ratio of the polyetherimide base layer. The proportion of polyetherimide resin in Example 1 is lower than that in Example 3, resulting in a lower resin concentration in the casting solution, and the density of the base layer skeleton formed after phase inversion is insufficient. Although the three-dimensional network structure is still slightly weak after crosslinking by 1,6-hexanediamine, the solvent penetration between molecular chains is slightly more when immersed in cyclohexane; at the same time, the difference in the density of the base layer leads to the support effect of the selection layer, resulting in a slightly lower bubble point pressure and a slightly larger pore size, and the flux decay is slightly faster and the gel rejection rate is slightly lower during long-term filtration.

[0116] The solvent resistance and mechanical strength of Example 2 are close to those of Example 3, and only the elongation at break and flux retention rate are slightly lower, which is due to the high proportion of polyetherimide resin. Higher resin concentration makes the base layer skeleton more dense, and the three-dimensional network is more stable after crosslinking by 1,6-hexanediamine, so the weight loss rate and size change rate are close to the standard sample, and the tensile strength is better; but too high resin concentration will reduce the flowability of the casting solution, and the uniformity of the internal pore channel of the base layer will decrease during film scraping, and the dispersion effect of nano-SiO2 will be slightly poor, resulting in a decrease in the toughness of the base layer and a decrease in the elongation at break. At the same time, the lack of pore channel uniformity makes the filtration resistance fluctuate slightly, and the long-term flux retention rate is slightly lower.

[0117] The performance of Example 3 is the best, which is due to the synergistic optimization of the process parameters and the raw material ratio. The polyvinyl alcohol modified non-woven fabric ensures firm anchoring of the base layer, and the ratio of polyetherimide, polyethylene glycol and nano-SiO2 makes the casting solution uniformity best, and the base layer forms a reasonable structure of "finger-like large pores + surface micropores" after phase inversion; 1,6-hexanediamine is fully crosslinked to construct a stable three-dimensional network, and perfluorodecanethiol in the selection layer is uniformly anchored to improve the anti-pollution property, and the pore size is accurately controlled by crosslinking with trifluoroacetic anhydride and heat pressing in the post-processing. The balance of the density of the base layer, the selection layer retention accuracy and the anti-pollution property is achieved through the cooperation of each link, realizing the optimal matching of solvent resistance, mechanical properties and filtration performance.

[0118] The properties of Comparative Example 1 were significantly worse than those of Example 3, and the core problem was that the polyetherimide resin accounted for too high a proportion. The high resin concentration caused the viscosity of the casting solution to increase sharply, making it difficult to form a uniform system during stirring, and internal bubbles could not be completely removed by vacuum degassing. After blade coating, small pinholes and inhomogeneous areas appeared in the base layer. During phase inversion, the solvent and water bidirectional diffusion was blocked, the pore structure was disordered, the proportion of large pores increased, and 1,6-hexanediamine could not fully penetrate and crosslink, resulting in defects in the three-dimensional network. During cyclohexane immersion, the solvent penetrated in large quantities, causing a sharp increase in weight loss and dimensional change rate. The defects in the base layer caused the selective layer to be poorly attached, the pore size distribution was wide, and the mechanical properties and filtration stability were all decreased.

[0119] The overall performance of Example 4 was slightly worse than that of Example 3, and the core reason was the adjustment of the oil phase monomer concentration during the preparation of the polyimide selective layer. In Example 4, the concentration of trimesoyl chloride was lower than that of the standard sample, and although interfacial polymerization was still able to form a selective layer, the decrease in monomer concentration caused the polymerization reaction rate to be slightly slower, the crosslinking density of the selective layer was slightly lower, resulting in a slightly larger pore size and a slightly lower bubble point pressure. However, the base layer raw material ratio was consistent with the standard sample, 1,6-hexanediamine was fully crosslinked, and nano-SiO2 was uniformly dispersed, so the solvent resistance and mechanical properties were close to those of the standard sample. Only in long-term filtration, due to the slightly poorer density of the selective layer, the flux retention rate and retention accuracy were slightly decreased, but the overall performance still maintained a relatively high level.

[0120] The solvent resistance and retention accuracy of Example 5 were better than those of Example 3, and the mechanical properties fluctuated slightly, which was due to the increase in the oil phase monomer concentration. In Example 5, the concentration of trimesoyl chloride was higher than that of the standard sample, and the probability of monomer collision increased during interfacial polymerization, the reaction was more complete, the crosslinking density of the selective layer formed was higher, and the structure was more dense, so the weight loss and dimensional change were smaller during cyclohexane immersion, the bubble point pressure was higher, the pore size was smaller, and the retention rate was better. However, the high monomer concentration caused the polymerization reaction to generate a slightly intense heat, the local uniformity of the selective layer was slightly decreased, resulting in a slightly lower elongation at break. However, the base layer process was not adjusted, and the overall mechanical strength still maintained a relatively high level, and the long-term filtration stability performed excellently.

[0121] The properties of Comparative Example 2 were significantly worse than those of Example 3, and the core problem was that the oil phase monomer concentration was too low during the preparation of the polyimide selective layer. The low concentration of trimesoyl chloride caused the interfacial polymerization reaction to be incomplete, the crosslinking density of the selective layer formed was extremely low, the structure was loose, the pore size increased significantly and was unevenly distributed, resulting in a sharp decrease in bubble point pressure and a significant decrease in gel retention rate. At the same time, the loose selective layer could not effectively block the penetration of the solvent, and the weight loss and dimensional change rate increased significantly during cyclohexane immersion. Although the base layer process was consistent with the standard sample, the defects in the selective layer directly affected the overall performance, the flux decayed rapidly during long-term filtration, and the mechanical properties were slightly decreased due to the influence of the selective layer on the adhesion between the base layer, which comprehensively demonstrated the decisive role of monomer concentration on the performance of the selective layer.

[0122] From the performance differences of Examples 3, 4, 5 and Comparative Example 2, it can be clearly seen that the oil phase monomer concentration has a key influence on the performance of the filter membrane. Examples 4 and 5 slightly fluctuate the crosslinking density of the selection layer by adjusting the concentration of trimesoyl chloride, thereby affecting the retention accuracy and solvent resistance, but the base layer process is consistent with the standard sample, so the mechanical properties remain at a high level; Comparative Example 2 has too low an oil phase monomer concentration, which directly leads to defects in the structure of the selection layer. Even if the base layer process is normal, the overall performance will still be greatly degraded. This shows that the performance of the filter membrane is the result of the cooperation of the base layer support and the separation efficiency of the selection layer, and the monomer concentration of the selection layer directly determines the crosslinking density and structural density, which is the core factor affecting the retention accuracy and solvent resistance, and the base layer process is the basis for ensuring the mechanical properties.

[0123] Comparative Example 3 has poorer performance than Example 3, and the core reason is that the non-woven fabric is not modified with polyvinyl alcohol. After the polyvinyl alcohol transition layer is missing, the interfacial compatibility between the non-woven fabric and the polyetherimide base layer is greatly reduced, and the two are only physically connected, without the anchoring effect of hydrogen bonds mediated by hydroxyl groups, resulting in weak interfacial adhesion; at the same time, the rough surface of the non-woven fabric is not flattened, and the base layer thickness is uneven and easy to produce small cracks during the film scraping, and the 1,6-hexanediamine crosslinking cannot repair the interface defects. This makes the solvent easily penetrate into the interlayer to cause peeling during cyclohexane immersion, and the weight loss and dimensional change rate increase, the mechanical strength of the base layer is significantly reduced due to the interface defects, the pore size stability is insufficient during filtration, and the flux retention rate and retention rate decrease.

[0124] The mechanical properties, solvent resistance stability and filtration accuracy of Comparative Example 4 are all inferior to those of Example 3, and the root cause is that the polyetherimide base layer does not contain nano-SiO2. As an inorganic filler, nano-SiO2 can form physical support points in the base layer skeleton, improving the skeleton density and deformation resistance, and after its absence, the pores are prone to collapse or expansion due to uneven stress during the phase inversion of the base layer, and the pore structure stability decreases; at the same time, the reinforcing effect of nano-SiO2 disappears, and the tensile strength and toughness of the base layer are weakened, and the molecular chains are prone to displacement under stress during cyclohexane immersion, and the swelling degree increases. The double weakening of pore structure and mechanical properties leads to a decrease in bubble point pressure and a widening of pore size distribution, and the flux decay accelerates during long-term filtration, and the retention accuracy decreases.

[0125] The flux retention rate of Comparative Example 5 is significantly lower than that of Example 3, and other performances are close, and the key reason is that perfluorodecanethiol is not added to the oil phase. The fluorocarbon chain of perfluorodecanethiol is anchored on the surface of the selection layer through a thioester bond, which can reduce the adsorption of rubber segments by utilizing the low surface energy characteristic, and after its absence, the surface polarity of the selection layer is too high, and the rubber segments are easy to be adsorbed on the membrane surface and pore by hydrogen bonds or van der Waals forces; as the filtration proceeds, the adsorbed segments gradually accumulate and block the pores, resulting in rapid flux decay and a significant decrease in flux retention rate after 800h. However, perfluorodecanethiol does not directly affect the crosslinking structure of the base layer and the density of the selection layer, so the solvent resistance, mechanical properties and gel retention rate change little.

[0126] The solvent resistance, anti-pollution and pore size stability of Comparative Example 6 are all inferior to Example 3, and the core problem is that trifluoroacetic anhydride is not added during cyclohexane post-processing. Trifluoroacetic anhydride can react with the residual amino groups in the selection layer to form hydrophobic trifluoroacetyl groups, thereby improving the cross-linking density and hydrophobicity. The absence of trifluoroacetic anhydride results in insufficient cross-linking of the selection layer, and the molecular chain is prone to relaxation and swelling in cyclohexane, leading to an increase in weight loss and size change rate. At the same time, the surface polarity is not reduced, the adsorption capacity of the rubber segment is increased, and the flux retention rate is decreased. In addition, without the molecular modification of trifluoroacetic anhydride, the pore wall stability of the selection layer is insufficient, and it is difficult to form a uniform pore size distribution during hot pressing calibration, resulting in a slight decrease in retention accuracy.

[0127] Comparative Example 7 has the worst performance, especially the solvent resistance and mechanical properties are significantly degraded. The root cause is that the polyetherimide base layer is not cross-linked with 1,6-hexanediamine. The uncross-linked base layer relies on intermolecular forces to maintain the structure, and there is no three-dimensional network formed by covalent bonding. When immersed in cyclohexane, the molecular chain has strong mobility and is prone to swelling or even partial dissolution, resulting in a dramatic increase in weight loss and size change rate. The base layer skeleton lacks cross-linking support, and the mechanical strength decreases sharply, making it prone to breakage during stretching. At the same time, the uncross-linked base layer has a loose pore structure and cannot provide stable support for the selection layer, which is prone to cracking or falling off. The pore size distribution is disordered, and the gel retention rate and flux retention rate are deteriorated.

[0128] In summary, the performance data comparison of Examples and Comparative Examples shows that the excellent performance of the solvent-resistant filter membrane of the present application is due to the synergistic effect of the key processes and raw material ratios throughout the entire process. The core conclusions are as follows: First, non-woven polyvinyl alcohol modification, base layer nano-SiO2 doping, and 1,6-hexanediamine cross-linking are the basis for ensuring the stability of the membrane structure. The absence of any of these steps will result in decreased interlayer adhesion, weakened mechanical strength, or degraded solvent resistance. Second, the addition of perfluorodecanethiol to the oil phase of the selection layer and the introduction of trifluoroacetic anhydride during post-processing are key to improving anti-pollution. Both reduce rubber segment adsorption through surface chemical modification, and the absence of either will significantly reduce the flux retention rate. Third, the raw material ratio needs to be precisely controlled. Too high or too low a proportion of polyetherimide resin will disrupt the uniformity of the casting solution, leading to disordered pore structure.

[0129] The above description is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any skilled person in the art can make equivalent substitutions or changes within the technical scope disclosed by the present application and according to the technical solutions and inventive concepts of the present application, which should be covered within the protection scope of the present application.

Claims

1. A solvent resistant filter membrane, characterized in that, From bottom to top, it comprises a pretreated non-woven fabric, a polyetherimide base layer and a polyimide selection layer, wherein the preparation steps of the polyimide selection layer are as follows: The water phase is prepared by mixing m-phenylenediamine and tris(2-aminoethyl)amine with deionized water, and the oil phase is prepared by mixing m-benzene tricarboxylic chloride and perfluorodecanethiol with n-hexane; the base film is fixed, the water phase solution is poured, and the solution is allowed to stand for 3 min for adsorption; the excess liquid is removed by a rubber roller; the same volume of the oil phase solution is poured, and the solution is allowed to stand for 60 s for reaction; then the wet film is transferred to a vacuum oven at 110 DEG C for heat treatment for 20 min; the n-hexane and ethanol are used for rinsing; and the vacuum drying is performed at 70 DEG C for 4 h to complete the preparation of the polyimide selection layer.

2. The solvent resistant filter membrane of claim 1, wherein, The mass fraction of m-phenylenediamine in the water phase is 1-2 wt%, the mass fraction of tris(2-aminoethyl)amine in the water phase is 0-1 wt%, the mass fraction of m-benzene tricarboxylic chloride in the oil phase is 0.8-1.2 wt%, and the mass fraction of perfluorodecanethiol in the oil phase is 0.01-0.02 wt%.

3. The method of claim 1 or 2, wherein the solvent resistant filter membrane is prepared by the steps of: The method comprises the following steps: S1, raw material pretreatment: The non-woven fabric is immersed in a 5-10 wt% polyvinyl alcohol solution for 5-15 min, the liquid amount is controlled by a precision roller, and the non-woven fabric is dried in an oven at 80-100 DEG C for 5-10 min; the polyetherimide resin is broken and sieved, and washed with anhydrous ethanol three times and dried; S2, preparation of the polyetherimide base layer: The pretreated polyetherimide resin, polyethylene glycol, nano-SiO2 and N,N-dimethylacetamide are mixed, stirred at 80 DEG C for 6 h, and vacuum degassed for 12 h; the film is scraped on the non-woven fabric support by using a film scraper, immersed in a 18 DEG C pure water coagulation bath for 24 h, and then immersed in a 70 DEG C 1,6-hexanediamine 5 wt% ethanol solution for 4 h; the film is washed with ethanol and water three times and vacuum dried at 130 DEG C for 12 h; S3, post-treatment: After the polyimide selection layer is generated in situ on the polyetherimide base layer, the polyimide selection layer is immersed in cyclohexane for 48-72 h, during which a small amount of trifluoroacetic anhydride is added in several times, the film is washed with ethanol, and vacuum dried for 12 h; the film is calibrated in pore size by hot pressing for 30 s by using a flat plate hot press to obtain the finished filter membrane.

4. The method of claim 3, wherein the solvent resistant filtration membrane is prepared by the steps of: In the S1, the particle size of the broken polyetherimide resin is 45-150 mu m, and the water content after drying is less than 100 ppm.

5. The method for preparing the solvent-resistant filter membrane according to claim 3, wherein In the S2, the mass ratio of the polyetherimide resin, polyethylene glycol, nano-SiO2 and N,N-dimethylacetamide is 20-30:20-30:2:40-60.

6. The method of claim 3, wherein the solvent resistant filtration membrane is prepared by the steps of: In the S2, the thickness of the polyetherimide base layer is 30-50 mu m, the thickness of the polyimide selection layer is 0.1-0.5 mu m, and the thickness of the finished filter membrane is 130-250 mu m, and the pore size is 30-500 nm.

7. The method of claim 3, wherein the solvent resistant filtration membrane is prepared by the steps of: In the S3, the total amount of trifluoroacetic anhydride added accounts for 1-2% of the total mass of the system.

8. Use of the solvent resistant filter membrane according to any one of claims 1 to 2 in a solution polymerization gel reduction process of butadiene, characterized in that, The solvent-resistant filter membrane is arranged at one or more of the following process nodes to filter materials: The node after the catalyst is prepared and before the catalyst enters the aging tank; The node after the catalyst is aged and before the catalyst enters the polymerization kettle; The node after the polymerization reaction and before the glue solution enters the subsequent processing unit.

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