Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
  • B01D67/0081—After-treatment of organic or inorganic membranes
  • B01D67/0088—Physical treatment with compounds, e.g. swelling, coating or impregnation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
  • B01D71/06—Organic material
  • B01D71/30—Polyalkenyl halides
  • B01D71/32—Polyalkenyl halides containing fluorine atoms
  • B01D71/34—Polyvinylidene fluoride
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
  • B01D71/06—Organic material
  • B01D71/52—Polyethers
  • B01D71/522—Aromatic polyethers
  • B01D71/5222—Polyetherketone, polyetheretherketone, or polyaryletherketone
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/0427—Coating with only one layer of a composition containing a polymer binder
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
  • C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L27/12—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
  • C08L27/16—Homopolymers or copolymers or vinylidene fluoride
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2471/00—Characterised by the use of polyethers obtained by reactions forming an ether link in the main chain; Derivatives of such polymers

Definitions

• the invention relates to polymer membranes based on polyvinylidene fluoride (PVDF), a process for their production and their use for ultrafiltration.
• PVDF polyvinylidene fluoride
• Ultrafiltrations are predominantly carried out in aqueous systems, so that particularly high demands are placed on the mechanical and thermal stability (sterilisability up to 140 ° C.) of the membranes used for this, on their resistance to acids and alkalis and their selectively adjustable hydrophilic / hydrophobic properties become. These requirements cannot be met at the same time by the polymers used hitherto for the production of membranes; above all, in addition to good thermal resistance up to about 140 ° C., they do not show sufficient mechanical stability.
• PVDF Polyvinylidene fluoride
• EP-A2 0 249 513 a polymer used for the production of membranes
• PVP polyvinylpyrrolidone
• the object of the invention is therefore to provide polymer membranes which, in addition to high thermal and mechanical strength, have high hydrophilicity, large transmembrane flows and a retention capacity of 95% Have substances with molecular weights between 700 'and 1400.
• homogeneous solutions L1 which consist of 5 to 30 wt .-% of PVDF and 0.01 to 30 wt .-% of sulfonic acids (PEEKSO H) and / or their salts, according to known techniques Manufactures membranes, and the surface of these membranes is then treated with methanolic solutions L2, which consist of 0.1 to 5 wt .-% of sulfonic acids PEEKSO H and / or their salts.
• the sulfonic acids PEEKSO H are e.g.
• Preferred embodiments of the method according to the invention rens use homogeneous solutions L1 which consist of 5 to 30% by weight of PVDF and 0.01 to 1% by weight of the sulfonic acids PEEKSO-H and / or their salts.
• Suitable sulfonic acids PEEKSO-H or their salts for carrying out the process according to the invention are e.g. from polyether ether ketones of the formula (I), with values for n between 35 and 350 available.
• Preferred embodiments of the process according to the invention use sulfonic acids and / or their salts which are accessible from polyether ether ketones of the formula (I) with values for n between 50 and 300.
• Suitable sulfonic acids PEEKSO-H or their salts for carrying out the process according to the invention are e.g. those whose sulfur content, based on the sulfonic acid PEEKSO-H, is 1 to 9% by weight, preferred embodiments of the process according to the invention use sulfonic acids PEEKSO H or their salts with a sulfur content, based on the sulfonic acid PEEKSO H, of 2 to 7 % By weight.
• Sulphonic acids PEEKSO-H with this sulfur content are very hydrophilic on the one hand, but on the other hand no longer soluble in water at temperatures of 140 ° C (sterilization), which prevents them from washing out of the membrane, followed by a change in the membrane quality.
• Suitable homogeneous solutions L1 for carrying out the method according to the invention contain a solids content of 20 to 40% by weight, preferred embodiments have a solids content of 30% by weight.
• Suitable salts of the sulfonic acids PEEKSO-H for carrying out the process according to the invention are e.g. Sodium salts PEEKS0_Na and / or ammonium salts PEEKSO-NH. and / or zinc salts PEEKSO-Zn-s.
• Preferred solvents for the preparation of the homogeneous solutions L1 are dipolar aprotic, such as Dimethylformamide and / or N-methylpyrrolidone and / or dirnethylacetamide and / or dimethyl sulfoxide. Either only a single solvent can be used, or mixtures of several.
• the modified PVDF solution Ll is carried out by suspending the two polymers in the solvent or solvent mixture at temperatures between -40 ⁇ C and 25 ° C followed by rapid heating to about 80 C.
• the Solutions Ll processed according to known methods. They are applied, for example, to a polyethylene terephthalate fabric or fleece, which is attached to a glass plate, drawn with a doctor blade into a film, which is then precipitated into a membrane in a phase inversion process.
• the process according to the invention can also be used to produce other shaped articles, such as, for example, hollow fibers, foils or foams, in addition to flat membranes and tubular or capillary membranes using known techniques.
• the precipitation of the membranes can ⁇ at temperatures between -20 C and +50 ° C effected.
• Water or water / solvent mixtures can be used as precipitants; the solvents for this are preferably dipolar aprotic, such as dimethylformamide and / or N-methylpyrrolidone and / or dimethylacetamide and / or dimethyl sulfoxide.
• dipolar aprotic such as dimethylformamide and / or N-methylpyrrolidone and / or dimethylacetamide and / or dimethyl sulfoxide.
• Preferred embodiments of the process according to the invention use water / solvent mixtures which contain 5 to 50% by weight of solvent.
• a film of these sulfonic acids or their salts is applied to these membranes by known methods, such as by spraying or brushing on methanolic solutions L2 which contain 0.1 to 5% by weight of the sulfonic acids PEEKSO-H and / or their salts , which has layer thicknesses between 0.5 and 1 _m and which adheres well to this base. This measure will The hydrophilicity of the membrane surface is further increased.
• the suitable sulfonic acids PEEKSO H or their salts are the same ones that can be used to prepare the homogeneous solutions L1. In order to reduce the water solubility of the membrane surface, if necessary, the sulfonic acids PEEKSO or their salts on the surface can be crosslinked with Ca ++ ions.
• Preferred embodiments of the method according to the invention use a perfluorooctane sulfonate, such as e.g. the tetraethylammonium perfluorooctane sulfonate of formula (II).
• the process according to the invention is explained in more detail with the aid of the following examples.
• the characterization of the membranes with regard to size and distribution of the pores was carried out according to the "bubble point" test according to ASTM F 316, the transmembrane water flow was determined with the Berghof cell. Membranes wetted with ethanol were used to determine the transmembrane flow, wet membranes with diameters of 47 mm wetted with alcohol to determine the "bubble point". The measurements were repeated three times on three samples, and the gas passed above a pressure of 6 bar. The degree of sulfonation is defined as the number of moles of sulfur per repeating unit.
• This solution is applied to a polyethylene terephthalate fabric (single titer of the threads 18.1 denier, 45 threads, total titer 816 denier, 110 g / m, air permeability 100 l / m 2 sec, at a pressure of 20 mm water column), on a glass plate with a thickness of 3 mm attached, pulled out with a doctor blade 200 ⁇ r ⁇ and precipitated in deionized water at 4 ° C with a residence time of 30 minutes. The mixture is then rinsed under flowing deionized water at 10 ° C. for 18 hours, dried under room conditions and sprayed with a solution of 2% by weight of PEEKSO Na (degree of sulfonation 0.7) in methanol.
• PEEKSO Na degree of sulfonation 0.7
• the "bubble point" of the membrane produced under these conditions is greater than 6 bar, the water flow at 1 bar 600 lm-2h-1 and the retention against cytochro C.
• the "bubble point" of the membrane is greater than 6 bar, the water flow at 1 bar is 92 Im ⁇ 2h ⁇ 1, the retention capacity against cytochrome C is 36%.
• Example 4 18.9 g PVDF and 0.1 g PEEKSO Na are dissolved in 80 ml DMF and shaped into membranes according to Example 1. The "bubble point" is greater than 6 bar, the water flow at 1 bar 351 Im ⁇ 2h-1 and the retention against cytochrome C 95%.
• Example 4
• membranes are produced; water, to which 15% by weight dimethylformamide / liter has been added, is used as the precipitation bath.
• the "bubble point" of the membrane is larger
• the polymer membranes produced by the method according to the invention can be used in a wide variety of areas, e.g. in biotechnology, as ultrafiltration or as microfiltration membranes. In addition to high thermal and mechanical stability, they have excellent hydrophilic properties and show transmembrane flows of up to 700 im-2 h-lbar-l, a "bubble point" greater than 6 bar and a retention capacity for substances with molecular weights of up to 1300 from to 95%.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Separation Using Semi-Permeable Membranes (AREA)

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• 1989
  • 1989-02-15 DE DE3904544A patent/DE3904544A1/de active Granted
• 1990
  • 1990-02-12 WO PCT/DE1990/000091 patent/WO1990009232A1/de not_active Application Discontinuation
  • 1990-02-12 EP EP90902757A patent/EP0409950A1/de not_active Withdrawn
  • 1990-02-12 JP JP2502932A patent/JPH03503981A/ja active Pending
  • 1990-02-12 US US07/613,861 patent/US5151193A/en not_active Expired - Fee Related

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