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WO1996014913A1 - Cartouche filtrante rendue hydrophile et procede pour la fabriquer - Google Patents

Cartouche filtrante rendue hydrophile et procede pour la fabriquer Download PDF

Info

Publication number
WO1996014913A1
WO1996014913A1 PCT/US1995/001175 US9501175W WO9614913A1 WO 1996014913 A1 WO1996014913 A1 WO 1996014913A1 US 9501175 W US9501175 W US 9501175W WO 9614913 A1 WO9614913 A1 WO 9614913A1
Authority
WO
WIPO (PCT)
Prior art keywords
membrane
filter
cartridge
filter medium
hydrophilized
Prior art date
Application number
PCT/US1995/001175
Other languages
English (en)
Inventor
James F. Klemencic
Mary W. Tilley
Original Assignee
W.L. Gore & Associates, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by W.L. Gore & Associates, Inc. filed Critical W.L. Gore & Associates, Inc.
Priority to AU17358/95A priority Critical patent/AU1735895A/en
Publication of WO1996014913A1 publication Critical patent/WO1996014913A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
    • B01D63/06—Tubular membrane modules
    • B01D63/061—Manufacturing thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1692—Other shaped material, e.g. perforated or porous sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2411—Filter cartridges
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
    • B01D63/06—Tubular membrane modules
    • B01D63/067—Tubular membrane modules with pleated membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
    • B01D65/003—Membrane bonding or sealing

Definitions

  • This invention relates to a process for making integrity testable hydrophilic filter cartridges and to filter cartridges made by the process.
  • Filter media which are made of porous membranes are commonly made of a fluoropolymer, which is a hydrophobic material.
  • One such filter medium is made of stretched porous polytetrafluoroethylene.
  • These filters are strong and chemically inert, making them desirable for use as filters.
  • being hydrophobic they are not as useful in aqueous filtration systems as desired. But because of their strength and inertness, it has been a goal to render these hydrophobic filter media hydrophilic so that they may be used in aqueous systems.
  • hydrophobic is meant that a material referred to is resistant to wetting with water.
  • hydrophilic is meant that a material referred to is water-wettable. As applied to a description of filter media, the terms indicate whether the media is resistant to penetration by water or readily passes water through it.
  • the porous membrane used as the filter medium is treated with a hydrophilizing polymer and then the filter cartridge is assembled. It is common to use thermal sealing processes to bond the filter membrane to the cartridge housing.
  • Typical materials of construction for these housings include polytetrafluoroethylene, or tetrafluoroethylene copolymers or other fluoropolymers or polyolefins. Thus, bonding temperatures may range from 160°C to 400°C.
  • Integrity testing is performed in order to make certain that there are no pinholes in the membrane or defects at the bonding sites. Integrity testing for hydrophilic porous filter media is preferably carried out by completely wetting the pore structure of the membrane with water and applying air pressure to the cartridge. Air flow through the cartridge is then measured. If the measured flow is negligible, the cartridge is considered integral. If excessive air flow is detected, the cartridge fails the test. Ordinarily this excessive air flow is attributed to a physical defect in the cartridge.
  • Such a hydrophilic device can be integrity tested with a low surface tension fluid such as alcohol that will wet both hydrophilic and hydrophobic regions. This is undesirable because it requires introducing a contaminant, namely the wetting fluid which must then be flushed out.
  • a strip of porous hydrophobic membrane is initially treated along each edge to render the area along each edge impervious to air flow through it. This can be accomplished either by laminating a nonporous strip to the edges to prevent air flow through that area of the membrane or by densifying the edges in order to compress the material to the extent that the pores are eliminated.
  • the material is then treated with a hydrophilizing polymer.
  • the treated construction can then be shaped into any appropriate configuration for the filter cartridge and thermally bonded along the nonporous areas. Even though the thermal bonding has rendered the hydrophilic polymer ineffective at the bonding sites, the membrane does not allow airflow in those areas, so the filter cartridge is now able to pass the integrity test described above.
  • Figure 1 depicts the procedure by which lamination of the filter membrane to the nonporous strips on opposite edges occurs.
  • Figure 2a depicts the product of the lamination from the top and Figure
  • Figure 3 is a cutaway view of a filter cartridge with the filter membrane inside.
  • Figure 4 depicts a side view of a membrane in which the opposing edges have been densified as denoted by the crosshatching.
  • the membranes that can be treated by this invention can be any microporous or porous material that is utilized for filtration purposes. These have continuous pores from one side to the other. Thus, by “porous” and “microporous” is meant that the membrane has continuous passageways from one side to the other. As long as continuous pores are present in the membranes, the method for forming such pores is not restricted to a particular method. For example, stretching (i.e., expanding), bubbling, extraction, and the like may be used.
  • the membranes are usually hydrophobic and are usually composed of fluoropolymers such as polytetrafluoroethylene, or polyvinylidenefluoride or copolymers of tetrafluoroethylene. They can also be composed of polyolefins such as polypropylene and polyethylene. Preferably the starting membrane is a hydrophobic fluoropolymer.
  • Stretched polytetrafluoroethylene is an especially preferred membrane. It can have a porosity ranging usually from 15% to 95%, preferably from 50% - 95%.
  • the hydrophilizing medium can be a solution of any hydrophilic polymer which when deposited on the surface of the hydrophobic membrane, raises the surface free energy of the membrane so that it becomes more wettable by water. The requirements that must be met by this system are that the solution concentration be appropriate to the pore structure of the membrane being treated and that this membrane be readily wetted by the solvent. If the membrane is not directly wetted by the solvent, appropriate pre-wetting of the membrane should be accomplished so that the membrane will readily receive the hydrophilizing solution.
  • hydrophilizing polymer that can be used is a copolymer of a fluorine containing ethylenically unsaturated monomer and a non-fluorinated vinyl monomer containing a hydrophilic group.
  • Other polymers can be used including polyvinyl alcohol, and the like.
  • the fluorine-containing, ethylenically unsaturated monomer will be a vinyl monomer such as, for example, tetrafluoroethylene, vinyl fluoride, vinylidene fluoride, monochlorotrifluorethylene, dichlorodifluoroethylene, hexafluoropropylene, and the like. More broadly, the fluorine-containing monomer can be described as
  • CXY CFZ wherein Z can be fluorine or hydrogen and X and Y can each be selected from hydrogen, fluorine, chlorine and CF 3
  • the monomers that contain hydrophilic groups include those that have hydroxyl groups, carboxyl groups, sulfate groups, phosphoric acid groups, amide groups that may be N-substituted, and amino groups that may be N- substituted, or the like.
  • Monomers in which an alkylene oxide such as ethylene oxide or propylene oxide has been subjected to an additional reaction with the active hydrogen in these groups are also useful.
  • Those that yield copolymers containing hydrophilic groups by performing first copolymerization and then saponification, as for example, polymers containing vinyl acetate units, are also useful.
  • R is hydrogen or a methyl group and n and m are integers greater than or equal to one and preferably one to twenty.
  • the fluorine content of the fluorine-containing hydrophilic polymer used in the present invention may range usually from 2% to 60%, preferably from 10% to 60%, and most preferably 20%-60% on a weight basis.
  • the fluorine content of the fluorine-containing hydrophilic polymer becomes too high, the hydrophilic properties of the polymer may be lessened, though the heat resistance may increase.
  • the fluorine content becomes too low, adhesion of the polymer to the porous fluoropolymer membrane may be reduced and the heat resistance may be decreased.
  • a preferred copolymer for treating fluoropolymer membranes is a copolymer of vinyl alcohol and a fluorine containing monomer.
  • a typical tetrafluoroethylene/vinyl alcohol (TFFJVOH) copolymer treatment solution is a 1% (by weight) solution of TFFJVOH where the solvent is methanol/ethanol in a 4:1 ratio.
  • the composition by weight of TFE is 25% and VOH is 75%.
  • the filter cartridge can be any type of cartridge, and is not limited to any specific configuration.
  • a representative cartridge is described in PCT WO93/09862. This publication describes a cylindrical cartridge having a cylindrically pleated filter medium. Other types of cartridges that can be used include ones using stacked disk filter media, hollow fiber filter media, and the like.
  • a typical filter cartridge 20 is shown in Figure 3 which comprises a support structure made of cage 21 , end caps 24 and 24', an interior core (not shown), and a filter media 23 shown in the cutaway section of cage 21.
  • Cage 21 has perforations 22 to facilitate passage of aqueous liquid.
  • the nonporous thermoplastic strips are shown as 25 located at each end of the membrane under the potting.
  • a strip of membrane 11 preferably stretched porous PTFE obtained from W. L. Gore & Associates, Inc, is laminated along the edges of opposing sides with a thin strip of a nonporous polymer 12.
  • the strip is preferably a thermoplastic such as a polyolefin, polyester, polyamide, or a fluoropolymer such as Teflon PFA, Teflon FEP, PVDF, and the like, by applying heat and/or pressure.
  • a convenient method is to feed the strips and membrane between the nips of heated roll 13 and roll 14.
  • a preferred strip is made of polypropylene.
  • the membrane is then hydrophilized by treating the laminate with the hydrophilizing polymer.
  • the hydrophilizing solution can be metered onto the porous filter membrane, thereby coating the pores of the membrane with the hydrophilizing polymer, as the membrane moves along a belt.
  • the treated membrane is then dried, preferably in an oven.
  • the opposing sides of the membrane can simply be densified along the edges, by subjecting the edges to pressure sufficient to densify the edges as shown at 15 in membrane 11 of Figure 4. Densification can be achieved by the use of opposing hard nip rolls or the like.
  • a solution of a hydrophilizing copolymer was prepared by dissolving TFE/VOH copolymer in a solvent mix of 4:1 methanol/ethanol to obtain a 1% by weight solution of the copolymer.
  • the copolymer was 25 weight % tetrafluoroethylene and 75 weight % vinyl alcohol.
  • the above membrane was exposed to molten polypropylene beads at about 200°C. Integrity testing was performed by immersing the construction in water, applying air pressure, and measuring the flow of air through the treated membrane.
  • Air flow through the construction was negligible. Such a construction when manufactured into a cartridge, would pass an integrity test in water.
  • cartridges in which the filter medium is made of polyvinylidenefluoride or a polyolefin such as polypropylene can be treated.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

Pour rendre les membranes hydrophobes utilisables pour la filtration de milieux aqueux, on rend ces membranes hydrophiles. Toutefois, lors de l'assemblage des cartouches filtrantes, l'efficacité des agents hydrophiles peut facilement être diminuée si on applique de la chaleur lors de la fabrication de la cartouche. Ceci a une influence sur l'étanchéité de la cartouche assemblée. Pour éviter ce manque visible d'étanchéité de la cartouche filtrante (20) lorsque cette étanchéité est vérifiée par immersion dans l'eau, on rend les bords de la membrane imperméables à l'air. Une bande de la membrane filtrante (23) est traitée suivant chaque bord en appliquant une bande non poreuse (25) à ce bord, ou en la compactant. La membrane (23) est ensuite traitée par un polymère pour la rendre hydrophile. La membrane traitée peut à ce moment être mise sous la forme d'un cylindre, généralement plissé, et être fixée/ à chaud à ses extrémités à une structure de support de la cartouche filtrante. Comme la fixation se fait dans la région imperméable à l'air, le revêtement hydrophile des autres régions n'est pas détruit. Le système de filtre peut maintenant subir avec succès le test d'étanchéité susmentionné.
PCT/US1995/001175 1994-11-14 1995-01-26 Cartouche filtrante rendue hydrophile et procede pour la fabriquer WO1996014913A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU17358/95A AU1735895A (en) 1994-11-14 1995-01-26 Hydrophilized filter cartridge and process for making same

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US33899894A 1994-11-14 1994-11-14
US08/338,998 1994-11-14

Publications (1)

Publication Number Publication Date
WO1996014913A1 true WO1996014913A1 (fr) 1996-05-23

Family

ID=23327022

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1995/001175 WO1996014913A1 (fr) 1994-11-14 1995-01-26 Cartouche filtrante rendue hydrophile et procede pour la fabriquer

Country Status (2)

Country Link
AU (1) AU1735895A (fr)
WO (1) WO1996014913A1 (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0965780A1 (fr) * 1998-06-16 1999-12-22 Bridgestone Corporation Soupape d'alimentation pour fluides
US6550498B2 (en) * 1998-06-16 2003-04-22 Seiko Epson Corporation Fluid supply valve
WO2003002239A3 (fr) * 2001-06-29 2004-02-12 Millipore Corp Structure filtrante a bords lamines et procede de fabrication
WO2005002712A1 (fr) * 2003-07-08 2005-01-13 U.S. Filter Wastewater Group, Inc. Post-traitement de membranes
US7090341B1 (en) 1998-07-15 2006-08-15 Seiko Epson Corporation Ink-jet recording device and ink supply unit suitable for it
AU2004253197B2 (en) * 2003-07-08 2010-05-27 Evoqua Water Technologies Llc Membrane post treatment
US8524794B2 (en) 2004-07-05 2013-09-03 Siemens Industry, Inc. Hydrophilic membranes
US20160061158A1 (en) * 2014-08-28 2016-03-03 Bha Altair, Llc Filter water management using hydrophilic material
US9868834B2 (en) 2012-09-14 2018-01-16 Evoqua Water Technologies Llc Polymer blend for membranes
US10322375B2 (en) 2015-07-14 2019-06-18 Evoqua Water Technologies Llc Aeration device for filtration system
US10617603B2 (en) 2016-01-22 2020-04-14 Baxter International Inc. Sterile solutions product bag
US11021275B2 (en) 2016-01-22 2021-06-01 Baxter International Inc. Method and machine for producing sterile solution product bags

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0456939A1 (fr) * 1990-05-18 1991-11-21 Japan Gore-Tex, Inc. Membrane poreuse hydrophile en fluoropolymère
WO1993009862A1 (fr) * 1991-11-15 1993-05-27 Memtec America Corporation Milieu filtrant et support en poly(tetra-fluoro ethylene) plisse
WO1993023153A1 (fr) * 1992-05-18 1993-11-25 Costar Corporation Membranes microporeuses soutenues
WO1994022553A1 (fr) * 1993-03-29 1994-10-13 W.L. Gore & Associates, Inc. Cartouche a membrane pour filtre de mise a l'air

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0456939A1 (fr) * 1990-05-18 1991-11-21 Japan Gore-Tex, Inc. Membrane poreuse hydrophile en fluoropolymère
WO1993009862A1 (fr) * 1991-11-15 1993-05-27 Memtec America Corporation Milieu filtrant et support en poly(tetra-fluoro ethylene) plisse
WO1993023153A1 (fr) * 1992-05-18 1993-11-25 Costar Corporation Membranes microporeuses soutenues
WO1994022553A1 (fr) * 1993-03-29 1994-10-13 W.L. Gore & Associates, Inc. Cartouche a membrane pour filtre de mise a l'air

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6394137B1 (en) 1998-06-16 2002-05-28 Seiko Epson Corporation Fluid supply valve
US6550498B2 (en) * 1998-06-16 2003-04-22 Seiko Epson Corporation Fluid supply valve
US6748979B2 (en) * 1998-06-16 2004-06-15 Bridgestone Corporation Fluid supply valve
EP0965780A1 (fr) * 1998-06-16 1999-12-22 Bridgestone Corporation Soupape d'alimentation pour fluides
US7559634B2 (en) 1998-07-15 2009-07-14 Seiko Epson Corporation Ink-jet recording device and ink supply unit suitable for it
US7090341B1 (en) 1998-07-15 2006-08-15 Seiko Epson Corporation Ink-jet recording device and ink supply unit suitable for it
US7350907B2 (en) 1998-07-15 2008-04-01 Seiko Epson Corporation Ink-jet recording device and ink supply unit suitable for it
US7422317B2 (en) 1998-07-15 2008-09-09 Seiko Epson Corporation Ink-jet recording device and ink supply unit suitable for it
WO2003002239A3 (fr) * 2001-06-29 2004-02-12 Millipore Corp Structure filtrante a bords lamines et procede de fabrication
US6913786B2 (en) 2001-06-29 2005-07-05 Millipore Corporation Laminated edge filter structure and method of making
AU2004253197B2 (en) * 2003-07-08 2010-05-27 Evoqua Water Technologies Llc Membrane post treatment
US7662212B2 (en) 2003-07-08 2010-02-16 Siemens Water Technologies Corp. Membrane post treatment
WO2005002712A1 (fr) * 2003-07-08 2005-01-13 U.S. Filter Wastewater Group, Inc. Post-traitement de membranes
US8057574B2 (en) 2003-07-08 2011-11-15 Siemens Industry, Inc. Membrane post treatment
US8262778B2 (en) 2003-07-08 2012-09-11 Siemens Industry, Inc. Membrane post treatment
US8524794B2 (en) 2004-07-05 2013-09-03 Siemens Industry, Inc. Hydrophilic membranes
US9868834B2 (en) 2012-09-14 2018-01-16 Evoqua Water Technologies Llc Polymer blend for membranes
US20160061158A1 (en) * 2014-08-28 2016-03-03 Bha Altair, Llc Filter water management using hydrophilic material
US10220353B2 (en) 2014-08-28 2019-03-05 Bha Altair, Llc Filter water management using hydrophilic material
US10322375B2 (en) 2015-07-14 2019-06-18 Evoqua Water Technologies Llc Aeration device for filtration system
US10617603B2 (en) 2016-01-22 2020-04-14 Baxter International Inc. Sterile solutions product bag
US11021275B2 (en) 2016-01-22 2021-06-01 Baxter International Inc. Method and machine for producing sterile solution product bags
US11564867B2 (en) 2016-01-22 2023-01-31 Baxter International Inc. Sterile solutions product bag
US11623773B2 (en) 2016-01-22 2023-04-11 Baxter International Inc. Method and machine for producing sterile solution product bags

Also Published As

Publication number Publication date
AU1735895A (en) 1996-06-06

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