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CN-121988188-A - Resin composition for filter membrane and application thereof

CN121988188ACN 121988188 ACN121988188 ACN 121988188ACN-121988188-A

Abstract

The invention discloses a resin composition for a filter membrane, which comprises 60-95wt% of polyvinylidene fluoride resin, 5-40wt% of amphiphilic vinylidene fluoride block copolymer, wherein the weight average molecular weight of the amphiphilic vinylidene fluoride block copolymer is more than or equal to 50 ten thousand, the weight average molecular weight of the amphiphilic vinylidene fluoride block copolymer is 0.2-30 ten thousand, the amphiphilic vinylidene fluoride block copolymer comprises 10-50wt% of first block, the first block contains 85-100wt% of vinylidene fluoride structural units, and 50-90wt% of second block contains 50-95wt% of vinylidene fluoride structural units and 5-50wt% of hydrophilic structural units. The filter membrane prepared by the resin composition for the filter membrane has excellent mechanical strength, good hydrophilic performance and good stability.

Inventors

  • ZENG YANG
  • ZHU WEIWEI
  • ZHENG YILEI
  • LU YANGTIAN

Assignees

  • 浙江省化工研究院有限公司
  • 中化蓝天集团有限公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (10)

  1. 1. A resin composition for a filter membrane, characterized by comprising: 60-95wt% of polyvinylidene fluoride resin, wherein the weight average molecular weight of the polyvinylidene fluoride is more than or equal to 50 ten thousand; 5-40 wt% of amphiphilic vinylidene fluoride block copolymer, wherein the weight average molecular weight of the amphiphilic vinylidene fluoride block copolymer is 0.2-30 ten thousand, The amphiphilic vinylidene fluoride block copolymer comprises: 10-50wt% of a first block containing 85-100wt% of vinylidene fluoride structural units; 50-90 wt% of a second block containing 50-95 wt% of vinylidene fluoride structural units and 5-50 wt% of hydrophilic structural units.
  2. 2. The resin composition for a filter membrane according to claim 1, wherein the resin composition for a filter membrane comprises: 80-95wt% of polyvinylidene fluoride resin, wherein the weight average molecular weight of the polyvinylidene fluoride is more than or equal to 80 ten thousand; 5-20wt% of amphiphilic vinylidene fluoride block copolymer, wherein the weight average molecular weight of the amphiphilic vinylidene fluoride block copolymer is 1-10 ten thousand.
  3. 3. The resin composition for a filtration membrane according to claim 1 or 2, wherein the monomer forming the hydrophilic structural unit is a compound represented by the structural formula (1), Wherein R 1 、R 2 、R 3 is independently selected from hydrogen, halogen, perfluoroalkyl group having 1-6 carbon atoms, R 1 、R 2 、R 3 is at least one of halogen or perfluoroalkyl group having 1-6 carbon atoms, N is an integer of 0 to 12, R 4 is selected from hydrogen, lithium, sodium, potassium, ammonium, alkyl ammonium or alkylaryl ammonium ion with 1-6 carbon atoms, A compound shown in a structural formula (2), M is an integer of 1 to 100.
  4. 4. The resin composition for a filtration membrane according to claim 3, wherein the compound represented by the structural formula (1) is at least one selected from the group consisting of 2- (trifluoromethyl) acrylic acid and 2-fluoroacrylic acid.
  5. 5. The resin composition for a filtration membrane according to claim 1 or 2, wherein the first block further contains 0 to 15wt% of a first fluoroolefin structural unit, and the first fluoroolefin is at least one selected from hexafluoropropylene, chlorotrifluoroethylene, pentafluoropropene, tetrafluoropropene, trifluoropropene, perfluorobutene, tetrafluoroethylene, trifluoroethylene, perfluorovinyl ether, and vinyl fluoride.
  6. 6. The resin composition for a filtration membrane according to claim 1 or 2, wherein the second block further contains 0 to 5wt% of a first olefin structural unit, and the first olefin is at least one selected from hexafluoropropylene, chlorotrifluoroethylene, pentafluoropropene, tetrafluoropropene, trifluoropropene, perfluorobutene, tetrafluoroethylene, trifluoroethylene, perfluorovinyl ether, fluoroethylene, methyl acrylate, methyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, maleic acid ester, citraconic acid ester, vinyl acetate, vinylene carbonate, and acrylonitrile.
  7. 7. The resin composition for a filtration membrane according to claim 1 or 2, wherein the amphiphilic vinylidene fluoride block copolymer is produced by an iodine transfer living radical polymerization method.
  8. 8. The resin composition for a filtration membrane according to claim 1 or 2, further comprising an additive selected from at least one of polyethylene glycol, polyvinylpyrrolidone, ethylene glycol, glycerin, water, ethanol, acetone, and lithium chloride.
  9. 9. A fluoropolymer filtration membrane comprising the resin composition for a filtration membrane according to any one of claims 1 to 8.
  10. 10. The fluoropolymer filtration membrane of claim 9, wherein the fluoropolymer filtration membrane is used as a membrane module for sterilization filtration, desalination of sea water, separation of sewage, and purification of blood.

Description

Resin composition for filter membrane and application thereof Technical Field The invention relates to the field of polymers, in particular to a resin composition for a filter membrane and application thereof. Background Polyvinylidene fluoride films are receiving increasing attention for their good chemical stability, thermal stability, and higher mechanical strength. However, because polyvinylidene fluoride has relatively strong hydrophobicity, the polyvinylidene fluoride film is easy to be polluted in the use process, so that the application potential of the polyvinylidene fluoride film in the field of water treatment is limited. The pollution of the membrane is usually caused by adsorption and deposition of colloid particles, organic macromolecules, microorganisms and the like on the surface of the membrane and in the membrane holes, so that the flux of the filter membrane is reduced, the service life of the membrane is shortened, and the running cost of the treatment process is increased, so that the membrane is difficult to be directly applied to the scenes of water purification, domestic and industrial wastewater treatment and recycling, pharmaceutical/food/chemical product industrial separation and purification, blood purification and the like. In general, we consider that the surface of a film with high hydrophilicity can effectively reduce the adsorption and deposition of pollutants and reduce the pollution of the film, so that hydrophilic modification of polyvinylidene fluoride is a main means for solving the problems, and in many researches, hydrophilic polyvinyl alcohol, polyvinylpyrrolidone, graphene, nanoparticles, amphiphilic polymers and the like are mainly adopted to blend with hydrophobic polyvinylidene fluoride so as to improve the hydrophilic and anti-pollution performances of the film, however, water-soluble polymers, nano substances and the like are easy to run off from the inside of the film, so that the reliability of the film performance is poor. The amphiphilic polyvinylidene fluoride has hydrophilic and hydrophobic groups, excellent water treatment capacity, good removal effect on heavy metal ions, good biostability, difficult decomposition by microorganisms and great potential in membrane modification. Patent CN104610518B discloses a preparation method of polyvinylidene fluoride-polyacrylic acid block copolymer, patent CN104610519B discloses a preparation method of polyvinylidene fluoride-polyethylene glycol block copolymer, patent CN104558452B discloses a preparation method of polyvinylidene fluoride-polyvinylpyrrolidone block copolymer, among the amphiphilic vinylidene fluoride block copolymers, hydrophilic polymer chain segments mostly adopt strong hydrophilic chain segments such as polyacrylic acid, polyethylene glycol, polyvinylpyrrolidone and polyvinyl alcohol, and the strong hydrophilic chain segments have the problem of compatibility with fluorine-containing chain segments, so that the pore diameter of a film material is large, the filtering effect is poor, and the film making process is complex. In addition, the amphiphilic vinylidene fluoride block copolymer generally has a relatively low molecular weight, resulting in poor tensile strength and mechanical properties, and is difficult to use stably for a long period of time. Thus, it is highly desirable to provide an amphiphilic polyvinylidene fluoride membrane having good compatibility with fluoropolymer segments, excellent mechanical strength and filtration properties. Disclosure of Invention Technical problem to be solved by the invention In order to solve the problems of poor hydrophilic performance, large pore diameter, poor separation effect, poor compatibility of hydrophilic chain segments and fluorine-containing chain segments and the like of polyvinylidene fluoride membrane materials, the inventor discovers that polyvinylidene fluoride with high molecular weight has good mechanical properties, and amphiphilic vinylidene fluoride block copolymers with low molecular weight has good hydrophilicity and compatibility, so that a certain proportion of amphiphilic vinylidene fluoride block copolymers are blended in polyvinylidene fluoride resin, the problem of the compatibility of the hydrophilic chain segments and the fluorine-containing chain segments can be effectively solved while the hydrophilic chain segments are introduced into the surface of the membrane, and the integral mechanical strength and stability of the material are improved. Technical scheme for solving problems The present invention provides a resin composition for a filter membrane, comprising: 60-95wt% of polyvinylidene fluoride resin, wherein the weight average molecular weight of the polyvinylidene fluoride is more than or equal to 50 ten thousand; 5-40 wt% of amphiphilic vinylidene fluoride block copolymer, wherein the weight average molecular weight of the amphiphilic vinylidene fluoride block copolymer is 0.2-30 ten thousand, The amphiphilic v