WO1991018664A1 - Polyethersulfone/phenoxy resin blend filtration membranes - Google Patents
Polyethersulfone/phenoxy resin blend filtration membranes Download PDFInfo
- Publication number
- WO1991018664A1 WO1991018664A1 PCT/US1991/003676 US9103676W WO9118664A1 WO 1991018664 A1 WO1991018664 A1 WO 1991018664A1 US 9103676 W US9103676 W US 9103676W WO 9118664 A1 WO9118664 A1 WO 9118664A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- membrane
- polymer
- phenoxy resin
- polyethersulfone
- blend
- Prior art date
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 96
- 229920006393 polyether sulfone Polymers 0.000 title claims abstract description 55
- 229920006287 phenoxy resin Polymers 0.000 title claims abstract description 52
- 239000013034 phenoxy resin Substances 0.000 title claims abstract description 52
- 239000000203 mixture Substances 0.000 title claims abstract description 36
- 238000001914 filtration Methods 0.000 title claims abstract description 24
- 239000004695 Polyether sulfone Substances 0.000 title abstract description 28
- 229920000642 polymer Polymers 0.000 claims abstract description 45
- 239000012530 fluid Substances 0.000 claims abstract description 8
- 230000002209 hydrophobic effect Effects 0.000 claims abstract description 7
- 238000002844 melting Methods 0.000 claims abstract description 4
- 230000008018 melting Effects 0.000 claims abstract description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 14
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical group CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 12
- 238000000108 ultra-filtration Methods 0.000 claims description 7
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 claims description 6
- 239000011159 matrix material Substances 0.000 claims description 6
- 238000010791 quenching Methods 0.000 claims description 6
- 230000000171 quenching effect Effects 0.000 claims description 6
- 239000002904 solvent Substances 0.000 claims description 6
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 claims description 5
- 239000012982 microporous membrane Substances 0.000 claims description 4
- HTVITOHKHWFJKO-UHFFFAOYSA-N Bisphenol B Chemical compound C=1C=C(O)C=CC=1C(C)(CC)C1=CC=C(O)C=C1 HTVITOHKHWFJKO-UHFFFAOYSA-N 0.000 claims description 3
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 2
- 229920001577 copolymer Polymers 0.000 claims 1
- 238000009472 formulation Methods 0.000 abstract description 5
- 239000002245 particle Substances 0.000 abstract description 4
- 229920002521 macromolecule Polymers 0.000 abstract description 3
- 229920005597 polymer membrane Polymers 0.000 abstract description 3
- 238000002156 mixing Methods 0.000 abstract description 2
- 239000003570 air Substances 0.000 description 13
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 11
- 239000011148 porous material Substances 0.000 description 10
- 239000000243 solution Substances 0.000 description 7
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 6
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 125000000951 phenoxy group Chemical group [H]C1=C([H])C([H])=C(O*)C([H])=C1[H] 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- KUBDPQJOLOUJRM-UHFFFAOYSA-N 2-(chloromethyl)oxirane;4-[2-(4-hydroxyphenyl)propan-2-yl]phenol Chemical compound ClCC1CO1.C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 KUBDPQJOLOUJRM-UHFFFAOYSA-N 0.000 description 3
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 3
- 229920004695 VICTREX™ PEEK Polymers 0.000 description 3
- 239000000706 filtrate Substances 0.000 description 3
- 235000011187 glycerol Nutrition 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229920001223 polyethylene glycol Polymers 0.000 description 3
- 239000002952 polymeric resin Substances 0.000 description 3
- 229920003002 synthetic resin Polymers 0.000 description 3
- 102000036675 Myoglobin Human genes 0.000 description 2
- 108010062374 Myoglobin Proteins 0.000 description 2
- 229920012266 Poly(ether sulfone) PES Polymers 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- NKWKILGNDJEIOC-UHFFFAOYSA-N 2-(2-chloroethyl)oxirane Chemical compound ClCCC1CO1 NKWKILGNDJEIOC-UHFFFAOYSA-N 0.000 description 1
- 241000894006 Bacteria Species 0.000 description 1
- 229930185605 Bisphenol Natural products 0.000 description 1
- 241000589539 Brevundimonas diminuta Species 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229920006397 acrylic thermoplastic Polymers 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000000783 alginic acid Substances 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 238000000855 fermentation Methods 0.000 description 1
- 230000004151 fermentation Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 239000012633 leachable Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- KHUXNRRPPZOJPT-UHFFFAOYSA-N phenoxy radical Chemical compound O=C1C=C[CH]C=C1 KHUXNRRPPZOJPT-UHFFFAOYSA-N 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920002492 poly(sulfone) Polymers 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229940068918 polyethylene glycol 400 Drugs 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000001223 reverse osmosis Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000011877 solvent mixture Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000002943 spectrophotometric absorbance Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- ISXSCDLOGDJUNJ-UHFFFAOYSA-N tert-butyl prop-2-enoate Chemical compound CC(C)(C)OC(=O)C=C ISXSCDLOGDJUNJ-UHFFFAOYSA-N 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
Classifications
-
- 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
- B01D71/66—Polymers having sulfur in the main chain, with or without nitrogen, oxygen or carbon only
- B01D71/68—Polysulfones; Polyethersulfones
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L81/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing sulfur with or without nitrogen, oxygen or carbon only; Compositions of polysulfones; Compositions of derivatives of such polymers
- C08L81/06—Polysulfones; Polyethersulfones
Definitions
- This invention concerns porous polymer filtration membranes and, more particularly, high tensile strength, low melting point porous membranes which may be formed from a blend of polyethersulfone (PES) polymer and phenoxy resin.
- PES polyethersulfone
- the invention also concerns a process for preparing porous membranes and a process for filtering a fluid through such a porous filtration membrane.
- Microporous and ultrafiltration membranes are well known in the particle filtration industry.
- the material or matrix of these membranes comprises suitable organic plastics such as nylons, polysulfones, acrylics, and the like.
- Their filtration mechanism is a combination of size exclusion (sieving) and absorption or adsorption on the walls of the pores inside the membrane.
- ⁇ microporous the typical inner width of the membrane pores is in the range that passes macromolecules and retains particles contained in a fluid. Below this range, are “ultrafiltration” (UF) membranes which serve to filter macromolecules rather than particles, and “reverse osmosis” (RO) membranes which serve to separate ions.
- UF ultrafiltration
- RO reverse osmosis
- Polyethersulfone polymer has been shown to be miscible in a common solvent (DMF or DMSO) , with phenoxy resin (V.B. Singh and D.J. Walsh, J. Macromol, Sci.-Phys., B25 (1 & 2) , 65-87, 1986). Also shown is that the melting temperature of cast films of blended PES/phenoxy resin is lowered by using more phenoxy resin (relative to PES) in the blend. Not suggested is a membrane made from such a blend nor was such a film suggested to be porous or to be useful as a filtration membrane.
- porous filtration membranes can be made comprising a homogeneous blend of polyethersulfone polymer and phenoxy resin polymer.
- blended polymer filtration membranes are hydrophobic.
- the hydrophobic filtration membranes of the invention can be used for many purposes, e.g., as a vent filter to keep air sterile in fermentation tanks.
- phenoxy resin inherently has lower tensile strength than PES polymer, we have found that filtration membranes of the invention made from blended relative amounts of PES polymer and phenoxy resin unexpectedly are substantially stronger in this regard than the PES polymer membranes.
- the membranes of the invention have a lowered softening or melt temperature making for ease in safely melt-sealing the individual filtration membrane while retaining its porosity.
- the membranes can be used in disc form as a housed porous filter membrane component, in a melt-compatible thermoplastic device for the membrane, such as a device of the type described in U.S. Patent No. 4,444,661, which description is incorporated herein by reference.
- the invention in one preferred aspect concerns a porous filtration membrane, which preferably may be a microporous membrane or an ultrafiltration membrane.
- the membrane matrix comprises a homogeneous blend of polyethersulfone polymer and phenoxy resin polymer.
- the polyethersulfone polymer preferably comprises such polymer having the formula I
- the phenoxy resin polymer preferably comprises such polymer having the formula II
- a preferred membrane is one wherein the blend comprises (based on the total amount of the polyethersulfone polymer and phenoxy resin polymer included in the blend) an amount of polyethersulfone polymer, preferably about 50 to 90 wt.%, relative to the amount of phenoxy resin polymer, preferably about 50 to 10 wt.%, such that with respect to certain properties, the membrane surpasses in performance a comparable membrane made only with polyethersulfone polymer.
- the preferred relative amounts it is found that the.
- the softening or melt temperature of the membrane is advantageously lower and also the tensile strength is advantageously higher, than that of a comparable membrane made only with polyethersi ' lfone polymer.
- blending polyethersulfone with phenoxy resin in a polymer membrane formulation importantly results in a stronger membrane.
- the membrane should possess sufficient strength to survive various processing operations such as a slitting operation wherein the membrane is slit to the proper width to be processed further for use in flat stock and pleated devices.
- the increased strength also allows the membrane to be conveniently folded and pleated for insertion in a cartridge device and to resist damage when the cartridge is sterilized with steam.
- the plastic components of a membrane cartridge are subjected to significant contraction and expansion forces as the device is heated up and cooled down. These forces have a deleterious effect on the already stressed pleated folds in the membrane.
- Polyethersulfone is reported to have a glass transition temperature, T G , of 230 C C.
- Phenoxy resin typically begins to soften at 92°C.
- the blend comprises about 50 to 90 wt.% of polyethersulfone polymer and about 50 to 10 wt.% of phenoxy resin polymer based upon the total amount of the polyethersulfone polymer and phenoxy resin polymer included in the blend.
- the phenoxy resin polymer has the formula where R of formula II is methyl.
- the invention concerns a process of preparing a porous filtration membrane, which comprises forming a homogeneous blended solution of matrix solutes consisting essentially of polyethersulfone polymer and a phenoxy resin polymer in a compatible solvent, forming the resulting solution in a film, quenching the film in a suitable quenching medium, and drying the resulting film.
- the blend solution preferably comprises about 50 to 90 wt.% of PES polymer and about 50 to 10 wt.% of phenoxy resin polymer based upon the total amount of the
- PES polymer and phenoxy resin polymer included in the blend Any of various suitable art-recognized solvents or solvent mixtures may be employed of which N- methylpyrrolidone is preferred.
- a suitable vehicle or additive that is compatible with the blend may also be employed, such as PEG or glycerine.
- Any of various suitable quenching media may be employed, among which water is preferred.
- the invention concerns a process for filtering an aqueous fluid comprising causing said fluid to flow through a porous filtration membrane as described having a matrix as described comprising a homogeneous blend of polyethersulfone polymer and a phenoxy resin polymer.
- the membrane may be a microporous membrane or an ultrafiltration membrane.
- the polyethersulfone polymer comprises such polymer having the above formula I, preferably the phenoxy resin polymer comprises polymer having the above formula II.
- the membrane can be made thinner, i.e., of a selected thickness that still provides suitable strength, which results in reducing the hydrodynamic resistance and imparts a faster water flow and a higher level of throughput to the membrane.
- the water bubble point is a test to measure the largest pore size of a filter, based on the air pressure necessary to force liquid from the pores of a wetted filter. The larger the pore, the less pressure to vacate it. Air passing through the empty pore is detected as bubbles. The differential pressure to force the first bubble out is defined as the bubble point.
- the relationship between the bubble point pressure and the diameter of the large pores is given by: B ⁇ cos ⁇
- Air flow depends chiefly on the differential pressure, and on the total porosity and area of a filter. The total amount of air that can be filtered is also a function of contamination in the flow. The Gurley and Frazier tests are two common measurements of filter air flow.
- Water flow The water flow/flux test measures the rate at which water will flow through a filter - a variable of differential pressure, porosity, and filter area. Flow rates are commonly expressed in either seconds/100 ml., gallons/minute/ feet squared or milliliters/ minute/centimeters squared at a given pressure. EXAMPLE 1.
- the polymers used were from commercial sources: the polyethersulfone was Victrex ® 5200P, I.C.I. , and the phenoxy resin [4,4'-(l-meth'ylethylidene)bisphenol, polymer with (chloro ethyl)oxirane, M.W. 14,000-16,000] was UCAR 1 " phenoxy resin PKHH, Union Carbide.
- Films of each in 10 mil thickness were cast on a glass plate and oven dried at 110-120°C.
- Polyethersulfone Membrane 0.2 - A membrane similar to the membrane of paragraph 2 A) but differing primarily in its omission of the phenoxy resin was prepared as follows: Polyethersulfone (VictrexTM 5200P) , dimethylformamide and polyethyleneglycol 400 (used as a pore former for microporous membranes) were mixed in the ratio 13:18:69. The mixture was stirred to homogeneity and cast at 10-12 mil on glass or stainless steel. It was subjected to 60-70% relative humidity ambient air until it became opaque. The film was then immersed in water to complete coagulation and leach out excess solvent, for 2-12 hours. It was then dried at ambient to 70°C.
- the membrane obtained was spontaneously water wettable. It exhibited 100% bacteria retention when challenged with 10 7 /cm 2 of Pseudomonas diminuta.
- the membrane had the following flow characteristics: Kerosene Bubble Point 22 psi Water Bubble Point 53 psi Air Flow 2.7 lit/cm 2 -min at 10 psi
- Membranes were prepared by the method of Example 2 A) having different percentages of phenoxy resin tabulated as follows:
- PES/PHENOXY ULTRAFILTRATION MEMBRANE A homogeneous blend in N-methylpyrrolidone of 15% total resin was prepared from the following formulation: PES (Victrex ® 5200P) 26.9 g 13.43%
- Phenoxy Resin (Phenoxy PKHH) 3.1 g 1.57% NMP 170.0 g 85.00%
- the phenoxy resin was predissolved in the NMP in a beaker on a stirplate with agitation, dissolving in about one hour.
- the PES was added and agitation was continued for another two hours to provide a clear blend.
- the blend was cast at 10 mils, immersed in ambient water right after casting, leached and air dried overnight. The membrane appeared very shiny on the air side and less shiny on the belt side.
- a water flow test was performed in a filter (Amicon ® ) cell with the shiny (air) side toward the pressure.
- the average water flow rate was 0.98 cc/mm/cm 2 at 40 psi.
- a myoglobin solution (MW, 17,800; 0.1%) in Trismabase buffer was filtered through the membrane with the shiny (air) side up (toward the flow) .
- the average flow rate was
Abstract
Porous blended polymer (polyethersulfone, phenoxy resin) filtration membranes are provided which are hydrophobic, strong, have a lowered melt temperature, and are useful for filtering macromolecules or particles from fluids. Thus, blending polyethersulfone with phenoxy resin in a porous polymer membrane formulation importantly results in a stronger and lower melting membrane than a comparable membrane made only with polyethersulfone polymer.
Description
POLYEIHERSU FONE/PHENOXY RESIN BLEND FILTRATION MEMBRANES
Field of the Invention This invention concerns porous polymer filtration membranes and, more particularly, high tensile strength, low melting point porous membranes which may be formed from a blend of polyethersulfone (PES) polymer and phenoxy resin. The invention also concerns a process for preparing porous membranes and a process for filtering a fluid through such a porous filtration membrane.
Background of the Invention Microporous and ultrafiltration membranes are well known in the particle filtration industry. The material or matrix of these membranes comprises suitable organic plastics such as nylons, polysulfones, acrylics, and the like. Their filtration mechanism is a combination of size exclusion (sieving) and absorption or adsorption on the walls of the pores inside the membrane. To be considered ■■microporous", the typical inner width of the membrane pores is in the range that passes macromolecules and retains particles contained in a fluid. Below this range, are "ultrafiltration" (UF) membranes which serve to filter macromolecules rather than particles, and "reverse osmosis" (RO) membranes which serve to separate ions. The smaller the pore size, the slower the rate at which a*filtrate can be passed. To be useful for a particular application, the fluid flow rate through the membrane must therefore be reasonably high.
In agueous filtration, it is desirable to have membranes that are easily wettable and that have as little leachable material as possible. Such hydrophilic membranes containing an inherently hydrophobic polyamide, polyimide or polyethersulfone polymer are described in European patent document no. 0 228 072 dated July 8, 1987.
Polyethersulfone polymer has been shown to be miscible in a common solvent (DMF or DMSO) , with phenoxy resin (V.B. Singh and D.J. Walsh, J. Macromol, Sci.-Phys., B25 (1 & 2) , 65-87, 1986). Also shown is that the melting temperature of cast films of blended PES/phenoxy resin is lowered by using more phenoxy resin (relative to PES) in the blend. Not suggested is a membrane made from such a blend nor was such a film suggested to be porous or to be useful as a filtration membrane.
Summary of the Invention We have now found that useful porous filtration membranes can be made comprising a homogeneous blend of polyethersulfone polymer and phenoxy resin polymer. We have also found unexpectedly that such blended polymer filtration membranes are hydrophobic. The hydrophobic filtration membranes of the invention can be used for many purposes, e.g., as a vent filter to keep air sterile in fermentation tanks. Whereas phenoxy resin inherently has lower tensile strength than PES polymer, we have found that filtration membranes of the invention made from blended relative amounts of PES polymer and phenoxy resin unexpectedly are substantially stronger in this regard than the PES polymer membranes. Also, the membranes of the
invention have a lowered softening or melt temperature making for ease in safely melt-sealing the individual filtration membrane while retaining its porosity. For example, the membranes can be used in disc form as a housed porous filter membrane component, in a melt-compatible thermoplastic device for the membrane, such as a device of the type described in U.S. Patent No. 4,444,661, which description is incorporated herein by reference.
Detailed Description of the Invention The invention in one preferred aspect concerns a porous filtration membrane, which preferably may be a microporous membrane or an ultrafiltration membrane. The membrane matrix comprises a homogeneous blend of polyethersulfone polymer and phenoxy resin polymer. The polyethersulfone polymer preferably comprises such polymer having the formula I
[(C6H4-S02-C6H4-0)n] I
The phenoxy resin polymer preferably comprises such polymer having the formula II
where R is methyl or ethyl, preferably a polyhydroxyether of bisphenol A or bisphenol B. A preferred membrane is one wherein the blend comprises (based on the total amount of the polyethersulfone polymer and phenoxy resin polymer included in the blend) an amount of polyethersulfone polymer, preferably about 50 to 90 wt.%, relative to the amount of phenoxy resin polymer, preferably about 50 to 10 wt.%, such that with respect to certain properties, the
membrane surpasses in performance a comparable membrane made only with polyethersulfone polymer. Thus, in the preferred relative amounts, it is found that the. softening or melt temperature of the membrane is advantageously lower and also the tensile strength is advantageously higher, than that of a comparable membrane made only with polyethersi'lfone polymer. Thus, blending polyethersulfone with phenoxy resin in a polymer membrane formulation importantly results in a stronger membrane. More specifically, the membrane should possess sufficient strength to survive various processing operations such as a slitting operation wherein the membrane is slit to the proper width to be processed further for use in flat stock and pleated devices. The increased strength also allows the membrane to be conveniently folded and pleated for insertion in a cartridge device and to resist damage when the cartridge is sterilized with steam. When so sterilized the plastic components of a membrane cartridge are subjected to significant contraction and expansion forces as the device is heated up and cooled down. These forces have a deleterious effect on the already stressed pleated folds in the membrane. Polyethersulfone is reported to have a glass transition temperature, TG, of 230CC. Phenoxy resin typically begins to soften at 92°C. Preferably, for purposes of lower melt temperature and increased tensile strength, as indicated, the blend comprises about 50 to 90 wt.% of polyethersulfone polymer and about 50 to 10 wt.% of phenoxy resin polymer based upon the total amount of the polyethersulfone polymer and phenoxy resin polymer included
in the blend. Preferably, for these purposes, the phenoxy resin polymer has the formula where R of formula II is methyl.
In another preferred aspect, the invention concerns a process of preparing a porous filtration membrane, which comprises forming a homogeneous blended solution of matrix solutes consisting essentially of polyethersulfone polymer and a phenoxy resin polymer in a compatible solvent, forming the resulting solution in a film, quenching the film in a suitable quenching medium, and drying the resulting film. The blend solution preferably comprises about 50 to 90 wt.% of PES polymer and about 50 to 10 wt.% of phenoxy resin polymer based upon the total amount of the
PES polymer and phenoxy resin polymer included in the blend. Any of various suitable art-recognized solvents or solvent mixtures may be employed of which N- methylpyrrolidone is preferred. A suitable vehicle or additive that is compatible with the blend may also be employed, such as PEG or glycerine. Any of various suitable quenching media may be employed, among which water is preferred.
In another preferred aspect the invention concerns a process for filtering an aqueous fluid comprising causing said fluid to flow through a porous filtration membrane as described having a matrix as described comprising a homogeneous blend of polyethersulfone polymer and a phenoxy resin polymer. The membrane may be a microporous membrane or an ultrafiltration membrane. Preferably the polyethersulfone polymer comprises such polymer having the above formula I, preferably the phenoxy resin polymer
comprises polymer having the above formula II. As a result of the enhanced strength of the PES/phenoxy resin blend, as described, the membrane can be made thinner, i.e., of a selected thickness that still provides suitable strength, which results in reducing the hydrodynamic resistance and imparts a faster water flow and a higher level of throughput to the membrane.
The invention and the best mode of practicing the same are illustrated by the following examples of preferred embodiments of the invention. DEFINITIONS:
Water bubble point: The water bubble point is a test to measure the largest pore size of a filter, based on the air pressure necessary to force liquid from the pores of a wetted filter. The larger the pore, the less pressure to vacate it. Air passing through the empty pore is detected as bubbles. The differential pressure to force the first bubble out is defined as the bubble point. The relationship between the bubble point pressure and the diameter of the large pores is given by: B γ cos θ
where B is a constant, γ is liquid air surface tension, θ is the liquid solid contact angle and D is pore diameter.
Air Flow: Air flow depends chiefly on the differential pressure, and on the
total porosity and area of a filter. The total amount of air that can be filtered is also a function of contamination in the flow. The Gurley and Frazier tests are two common measurements of filter air flow.
Water flow: The water flow/flux test measures the rate at which water will flow through a filter - a variable of differential pressure, porosity, and filter area. Flow rates are commonly expressed in either seconds/100 ml., gallons/minute/ feet squared or milliliters/ minute/centimeters squared at a given pressure. EXAMPLE 1.
Solutions (10% by weight) of polyethersulfone (PES) and phenoxy resin (phenoxy) each as a solution in N- methylpyrrolidone were separately prepared and from these, homogeneous crystal clear blends were prepared as follows:
The polymers used were from commercial sources: the polyethersulfone was Victrex® 5200P, I.C.I. , and the phenoxy resin [4,4'-(l-meth'ylethylidene)bisphenol, polymer with (chloro ethyl)oxirane, M.W. 14,000-16,000] was UCAR1" phenoxy resin PKHH, Union Carbide.
Films of each in 10 mil thickness were cast on a glass plate and oven dried at 110-120°C.
Tests of the films for tensile strength showed that the PES/phenoxy blends B, C and D were each stronger than blend A (i.e., PES without phenoxy resin).
EXAMPLE 2. A modified blended formulation was prepared as follows:
1) Polyethylene glycol (E-400) 66.5
2) Phenoxy resin, BA Kelite® PKHH 1.4
3) PES, Victrex 52OOP 12.0
4) NMP, 22.8 g 7.6
5) DMF, 30 g 10.0 6) Deionized water 2.0
7) Glycerine 0.5
A) The phenoxy resin was added to the NMP and DMF (20g) and stirred until dissolved. The PES polymer was added to the PEG, to which the phenoxy solution was added, followed by the DMF (10g) , water and glycerine. The resulting clear blend [(viscosity, 3000 cps, 74°F) ] was cast in 15 mil thickness on a flat plate, subjected to humidity, dried, and the resulting membrane was formed into 47-mm discs. The discs were hydrophobic; the ratio, phenoxy:PES, is 11.7:100. Tensile strength (parallel) of the membrane was 542, 500, 500 and 520 psi. Elongation (parallel, average EB) was 13.15%. Burst pressure: 27.5, 28.0, 28.0 psi.
B) A similar formulation, except that the polymer components 2) and 3) in the blend were at 4.0 and 9.4% respectively, when cast as a membrane as in paragraph 2 A) gave improved results: burst pressure, 38-43 psi; tensiles at break, 854 and 886 psi; elongation, 31.2 and 18.3%. WBP (prewet in methanol) was 63.5, 62.5 psi; water flow (prewet in methanol), 28.9, 29.9 sec per 100 ml.
C) Polyethersulfone Membrane 0.2 - A membrane similar to the membrane of paragraph 2 A) but differing primarily in its omission of the phenoxy resin was prepared as follows: Polyethersulfone (Victrex™ 5200P) , dimethylformamide and polyethyleneglycol 400 (used as a pore former for microporous membranes) were mixed in the ratio 13:18:69. The mixture was stirred to homogeneity and cast at 10-12 mil on glass or stainless steel. It was subjected to 60-70% relative humidity ambient air until it
became opaque. The film was then immersed in water to complete coagulation and leach out excess solvent, for 2-12 hours. It was then dried at ambient to 70°C.
The membrane obtained was spontaneously water wettable. It exhibited 100% bacteria retention when challenged with 107/cm2 of Pseudomonas diminuta. The membrane had the following flow characteristics: Kerosene Bubble Point 22 psi Water Bubble Point 53 psi Air Flow 2.7 lit/cm2-min at 10 psi
Water Flow 23 ml/cm2-min at 10 psi
Tensile strength and other performance characteristics of comparable polyethersulfone membranes are described in the following examples.
EXAMPLE 3.
Membranes were prepared by the method of Example 2 A) having different percentages of phenoxy resin tabulated as follows:
Phenoxy Resin Concentration (% Bv Weight)
These membranes and membranes prepared without phenoxy resin by the method of Example 2 C) were compared for their relative performance characteristics with the typical result tabulated as follows:
PERFORMANCE CHARACTERISTICS
* The membrane was subjected to methanol-prewetting before test.
These results show that the average water bubble points of the hydrophobic PES/phenoxy membranes (allowing for film thickness) are lower than that of the hydrophilic PES membrane disc. The results also show that the PES/phenoxy membrane discs of the invention are stronger and have a relatively higher water flow rating.
EXAMPLE 4. PES/PHENOXY ULTRAFILTRATION MEMBRANE A homogeneous blend in N-methylpyrrolidone of 15% total resin was prepared from the following formulation: PES (Victrex® 5200P) 26.9 g 13.43%
Phenoxy Resin (Phenoxy PKHH) 3.1 g 1.57% NMP 170.0 g 85.00%
For the preparation of membranes the phenoxy resin was predissolved in the NMP in a beaker on a stirplate with agitation, dissolving in about one hour. The PES was added and agitation was continued for another two hours to provide a clear blend. The blend was cast at 10 mils, immersed in ambient water right after casting, leached and air dried overnight. The membrane appeared very shiny on the air side and less shiny on the belt side.
A water flow test was performed in a filter (Amicon®) cell with the shiny (air) side toward the pressure. The average water flow rate was 0.98 cc/mm/cm 2 at 40 psi. A myoglobin solution (MW, 17,800; 0.1%) in Trismabase buffer was filtered through the membrane with the shiny (air) side up (toward the flow) . The average flow rate was
0.0273 cc/mm/cm 2 at 40 psi. The filtrate appeared clear. Spectrophotometric absorbance analysis at a wavelength of 265 nm of a 5-fold dilution of the feed and filtrate showed that the resulting UF membrane retained 99.7% of the myoglobin feed.
Having described the invention, the embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
Claims
CLAIMS 1. .A filtration membrane having a porous isotropic matrix comprising a homogeneous blend of polyethersulfone polymer and phenoxy resin polymer.
2. The membrane of claim 1 wherein the membrane is a non-protein-rejecting microporous membrane.
3. The membrane of claim 1 wherein the membrane is an ultrafiltration membrane.
4. The membrane of claim 1 wherein the polyethersulfone polymer comprises polymer having the formula
[(C6H4-S02-C6H4-0)n]
5. The membrane of claim 1 wherein the phenoxy resin polymer comprises polymer having the formula
6. The membrane of claim 1 wherein the phenoxy resin polymer comprises a polyhydroxyether of bisphenol A.
7. The membrane of claim 1 wherein the phenoxy resin polymer comprises a polyhydroxyether of bisphenol B.
8. The membrane of claim 1 wherein the blend comprises an amount of polyethersulfone polymer relative to the amount of phenoxy resin polymer such that the softening temperature of the membrane is substantially lower than that of a comparable membrane made only with polyethersulfone polymer.
9. The membrane of claim 1 wherein the blend comprises about 50 to 90 wt.% of polyethersulfone polymer and about 50 to 10 wt.% of phenoxy resin polymer based upon the total amount of the polyethersulfone polymer and phenoxy resin polymer included in the blend.
10. The membrane of claim 5 wherein the phenoxy resin polymer has the formula where R is methyl.
11. The membrane of claim 1 wherein the blend comprises an amount of polyethersulfone polymer relative to the amount of phenoxy resin polymer such that the tensile strength of the membrane is substantially greater than that of a comparable membrane made only with polyethersulfone polymer.
12. A process of preparing a hydrophobic porous isotropic filtration membrane, which comprises forming a homogeneous blended solution of solutes consisting essentially of polyethersulfone polymer and a phenoxy resin polymer in a compatible solvent, forming the resulting solution in a film, quenching the film in a quenching medium, and drying the resulting film to obtain the isotripic membrane, the amount of polyethersulfone polymer relative to the amount of phenoxy resin polymer being such that the strength and melting characteristics of the resulting isotropic membrance are superior to that of a comparable membrane made only with polyethersulfone polymer.
13. The process of claim 10 wherein the solvent is N-methylpyrrolidone.
14. The process of claim 10 wherein the quenching medium is water.
15. A process for filtering an aqueous fluid comprising causing said fluid to flow through a filtration membrane according to claim 1 having a porous matrix comprising a homogeneous copolymer blend of polyethersulfone polymer and a phenoxy resin polymer.
16. A process according to claim 15 wherein the membrane is a microporous membrane.
17. A process according to claim 15 wherein the membrane is an ultrafiltration membrane.
18. A process according to claim 15 wherein the polyethersulfone polymer comprises polymer having the formula [(C6H4-S02-C6H4-0)n]
19. A process according to claim 15 wherein the phenoxy resin polymer comprises polymer having the formula
20. A process according to claim 15 wherein the phenoxy resin polymer is a polyhydroxyether of bisphenol A or bisphenol B.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US531,237 | 1990-05-31 | ||
US07/531,237 US5076935A (en) | 1990-05-31 | 1990-05-31 | Filtration membranes made from polyethersulfone/phenoxy resin blend |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1991018664A1 true WO1991018664A1 (en) | 1991-12-12 |
Family
ID=24116826
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1991/003676 WO1991018664A1 (en) | 1990-05-31 | 1991-05-23 | Polyethersulfone/phenoxy resin blend filtration membranes |
Country Status (2)
Country | Link |
---|---|
US (1) | US5076935A (en) |
WO (1) | WO1991018664A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015189175A1 (en) * | 2014-06-13 | 2015-12-17 | Basf Se | New membranes |
Families Citing this family (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5935092A (en) | 1990-12-20 | 1999-08-10 | Baxter International Inc. | Systems and methods for removing free and entrained contaminants in plasma |
US5788862A (en) * | 1992-05-13 | 1998-08-04 | Pall Corporation | Filtration medium |
US5480554A (en) * | 1992-05-13 | 1996-01-02 | Pall Corporation | Integrity-testable wet-dry-reversible ultrafiltration membranes and method for testing same |
US5733657A (en) * | 1994-10-11 | 1998-03-31 | Praxair Technology, Inc. | Method of preparing membranes from blends of polymers |
US5911880A (en) * | 1995-12-15 | 1999-06-15 | Research Corporation Technologies, Inc. | Self-wetting membranes from engineering plastics |
US5667562A (en) * | 1996-04-19 | 1997-09-16 | Kimberly-Clark Worldwide, Inc. | Spunbond vacuum cleaner webs |
US6190855B1 (en) * | 1996-10-28 | 2001-02-20 | Baxter International Inc. | Systems and methods for removing viral agents from blood |
CA2270413A1 (en) | 1996-11-08 | 1998-05-14 | Chong-Son Sun | Method for purifying blood plasma and apparatus suitable therefor |
US6168718B1 (en) | 1996-11-08 | 2001-01-02 | Pall Corporation | Method for purifying blood plasma and apparatus suitable therefor |
US6045899A (en) * | 1996-12-12 | 2000-04-04 | Usf Filtration & Separations Group, Inc. | Highly assymetric, hydrophilic, microfiltration membranes having large pore diameters |
US6518034B1 (en) | 1998-06-25 | 2003-02-11 | Abb Diagnostics, Ltd. | Test strip for blood glucose determination |
US7381279B2 (en) * | 2000-06-14 | 2008-06-03 | The Procter & Gamble Company | Article for deionization of water |
US6612447B1 (en) * | 2000-07-24 | 2003-09-02 | Baxter International Inc. | Blood collection systems and filters using a porous membrane element |
EP1494789A4 (en) * | 2002-04-16 | 2005-11-30 | Pall Corp | Hollow fibres |
DE102004009877B4 (en) * | 2004-02-26 | 2006-05-24 | Koch Membrane Systems Gmbh | Open-pored filtration membrane and process for its preparation |
US20090002941A1 (en) * | 2007-06-29 | 2009-01-01 | Rajiv Mongia | Air-permeable, hydrophobic membrane used in a computer device |
US7964697B2 (en) | 2008-08-13 | 2011-06-21 | General Electric Company | Polyarylether membranes |
US20100041837A1 (en) * | 2008-08-13 | 2010-02-18 | Gary William Yeager | Polyarylethers, blends and methods for making |
US7834134B2 (en) * | 2008-08-13 | 2010-11-16 | General Electric Company | Polyarylethers, blends and methods for making |
US8472171B2 (en) * | 2009-12-22 | 2013-06-25 | Intel Corporation | Method and system for cooling a computer device |
WO2023169949A1 (en) * | 2022-03-10 | 2023-09-14 | Cmed Aesthetics S.R.L. | Process for the preparation of sterile products |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3615024A (en) * | 1968-08-26 | 1971-10-26 | Amicon Corp | High flow membrane |
US4575385A (en) * | 1983-06-30 | 1986-03-11 | Monsanto Company | Permeation modified gas separation membranes |
-
1990
- 1990-05-31 US US07/531,237 patent/US5076935A/en not_active Expired - Fee Related
-
1991
- 1991-05-23 WO PCT/US1991/003676 patent/WO1991018664A1/en unknown
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3615024A (en) * | 1968-08-26 | 1971-10-26 | Amicon Corp | High flow membrane |
US4575385A (en) * | 1983-06-30 | 1986-03-11 | Monsanto Company | Permeation modified gas separation membranes |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015189175A1 (en) * | 2014-06-13 | 2015-12-17 | Basf Se | New membranes |
Also Published As
Publication number | Publication date |
---|---|
US5076935A (en) | 1991-12-31 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5076935A (en) | Filtration membranes made from polyethersulfone/phenoxy resin blend | |
US5178765A (en) | Hydrophilic membranes prepared from polyethersulfone/poly-2-oxazoline/polyvinylpyrrolidone blend | |
US8727136B2 (en) | Microfiltration membrane with improved filtration properties | |
EP0036315B1 (en) | Anisotropic membranes | |
EP1007195B1 (en) | Highly asymmetric polyethersulfone filtration membrane | |
US4900449A (en) | Filtration membranes and method of making the same | |
US5108607A (en) | Filtration membranes and method of making the same | |
US4964990A (en) | Filtration membranes and method of making the same | |
JP4388225B2 (en) | Process for producing an asymmetric monolithic sulfone polymer membrane for ultrafiltration | |
AU593866B2 (en) | Microporous membrane and method of making the same | |
ES2895153T3 (en) | Agarose Ultrafiltration Membrane Composites for Size-Based Separations | |
KR102626465B1 (en) | Method for preparing membranes using lactamide based solvents | |
JPH0679149A (en) | Wet-dry reversible ultrafiltering membrane capable of integrity testing and testing method thereof | |
US6258272B1 (en) | Internal hydrophilic membranes from blended anionic copolymers | |
TW201622805A (en) | Microporous polyvinylidene fluoride flat membrane | |
US11819807B2 (en) | Porous membrane and filter cartridge | |
EP3808436A1 (en) | Membrane system, method for its manufacture and its use | |
EP1149625B1 (en) | Internal hydrophilic membranes from blended anionic copolymers | |
EP0448647B1 (en) | Heat resistant microporous material production and products | |
CN112295423B (en) | Porous membrane and filter element | |
JP2001310117A (en) | Internally hydrophilic membrane of anion copolymr blend | |
JPS62258707A (en) | Filter film and its production | |
MXPA00010296A (en) | Membrane which comprises a blend of a polysulphone or a polyether sulphone and polyethylene oxide/polypropylene oxide substituted ethylene diamine |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): CA JP |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FR GB GR IT LU NL SE |
|
NENP | Non-entry into the national phase |
Ref country code: CA |