Abstract: An at least two layer, unsupported, continuous microporous membrane is disclosed. The at least two layer, unsupported, continuous microporous membrane may include at least two different membrane pore size layers or the pore sizes may have about the same pore size. Apparatus and processes for fabricating at least a two layer unsupported, continuous, microporous membrane are also disclosed.

Abstract: An at least two zone, unsupported, continuous microporous membrane is disclosed. The at least two zone, unsupported, continuous microporous membrane may include at least two different membrane pore size zones or the pore sizes may have about the same pore size. Apparatus and processes for fabricating at least a two zone unsupported, continuous, microporous membrane are also disclosed.

Abstract: The present invention provides a composite membrane comprising a porous support layer and a selective layer comprising a vinylacetate polymer. The invention also provides a process for preparing a vinylacetate polymer selective layer on a porous support by depositing a colloidal dispersion having colloid particles of the vinylacetate polymer on the porous support followed by annealing the deposited colloids to form a selective layer. The membranes are useful for separation of gas or liquid or vapor mixtures.

Abstract: An improved water purification system for production of USP purified water and/or USP water for injection include backwashable, chlorine tolerant microfilter or ultrafilter for initial filtration of the feed water (10). The filtrate from the filter (18) is provided to a dechlorinator (18) prior to being subjected to an optional, reverse osmosis membrane unit (60) and then to a still (66) which discharges purified water at USP standards for purified water or water for injection.

Abstract: The present invention provides for a method of producing an integral multilayered porous membrane by simultaneously co-casting a plurality of polymer solutions onto a support to form a multilayered liquid sheet and immersing the sheet into a liquid coagulation bath to effect phase separation and form a porous membrane. The support can be a temporary support or form an integrated support for the membrane. The plurality of layers may be of the same polymer or different, same concentration or viscosity or different and may be subjected to the same processing conditions or different ones to form unique structures.

Abstract: The invention disclosed relates to intrinsically bacteriostatic synthetic polymer membranes, and to process for the manufacture thereof. In one embodiment, bacteriostatic metal ions are attached to a surface of a preformed synthetic polymer membrane by static adsorption/adsorption and reduced to the metal in situ. In another embodiment, the instrinsically bacteriostatic membranes are formed by providing a casting solution of a membrane forming synthetic polymer and bacteriostatic metal ions, and casting into a bath containing a reducing agent for the metal ions to form the membrane containing the metal ions incorporated therein.

Abstract: A process for refining and degumming edible oils by ultrafiltration which produces a permeate fraction with reduced phosphatide content and retentate with increased phosphatide content, and wherein the ultrafiltration membrane is composed of a polymerical polymer of a vinylidene difluoride monomer.

Abstract: A porous thermoplastic resin film capable of functioning well as a separator of a cell is provided. The porous film is constituted with a thermoplastic resin and a filler, wherein XR defined by the following formula: XR=25×TGUR×d2/Y is smaller than 5, where Y(&mgr;m), TGUR (sec/100 cc), and d (&mgr;m) represent the thickness, the gurley value, and the average pore diameter of said film, respectively. The porous film constructed as shown above can reduce the internal resistance of a cell when used as a separator of the cell.

Abstract: The invention describes hydrophilically acting shaped objects, in particular semipermeable membranes for pyrogen retention, comprising a synthetic polymer component and an additive made from a copolymer made from vinylpyrrolidone and a vinylimidazole compound, and furthermore processes for manufacturing the shaped objects. The shaped objects of the invention exhibit such a high pyrogen retention capacity that the pyrogen concentrations present in the filtrates are in part below the detection limit of the gel clot LAL test.

Abstract: The present invention relates to laminated membranes formed by multi-layer processing techniques including alternating layers of thermoplastic urethane and a copolymer of ethylene and vinyl alcohol. The membranes are characterized in that hydrogen bonds are formed between the layers of thermoplastic urethane and the copolymer of ethylene and vinyl alcohol. The membranes are characterized in that hydrogen bonds are formed between the layers of thermoplastic urethane and the copolymer of ethylene and vinyl alcohol.

Abstract: A hydrophilic membrane that includes a hydrophobic polymer and a water-soluble polymer-metal complex is provided. This membrane is made by heating a mixture of a hydrophobic polymer, a metal compound, and a water-soluble polymer. The water-soluble polymer forms complexes with the metal compound and homogeneously entangles with the dissolved hydrophobic polymer to form a viscous dope. The dope is extruded through an annular orifice to form a hollow fiber. The fiber is put in an environment having a controlled humidity so that it becomes partially solidified, and then, the fiber is put in a coagulation bath. The hollow fiber is formed by phase inversion in the coagulation bath and is collected using a take-up wheel that is partially immersed in a leaching bath.

Abstract: An asymmetric membrane comprising a tubular polymer film in combination with a tubular braid on which the film is supported, requires the braid be macroporous and flexible, yet sufficiently strong to withstand continuous flexing, stretching and abrasion during use for microfiltration (MF) or ultrafiltration (UF). The specifications for a braid of a long-lived membrane are provided. A membrane is formed by supporting a polymer film in which particles of calcined &agr;-alumina are dispersed, on the defined tubular braid.

Abstract: A breathable, stretch-thinned barrier film having improved strength, processability and/or breathability is formed from a mixture of a thermoplastic polymer and cavated filler particles such as cyclodextrin. The cavated filler particles provide the film with enhanced breathability to water vapor due to their ring-like, conical, cylindrical or otherwise hollow molecular structure, yet the film remains substantially impermeable to aqueous liquids. The enhanced breathability occasioned by the cavated particles permits the use of relatively low filler levels and correspondingly high polymer levels, thereby enhancing the film strength. The filler may melt during extrusion of the molten polymer into a film, facilitating smooth processing, and re-crystallize into particles after the film is formed and cooled.

Abstract: A method of producing a hollow fiber membrane includes discharging a polyvinylidene fluoride solution comprising a polyvinylidene fluoride resin and a poor solvent at a temperature above a phase separation temperature into a cooling bath at a temperature below the phase separation temperature to coagulate the polyvinylidene fluoride resin. The hollow fiber membrane comprises a polyvinylidene fluoride resin having spherical structures that have an average diameter in the range of 0.3 to 30 &mgr;m.

Abstract: The present invention relates to cationically charge-modified membranes and methods of preparing such membranes. In one major aspect of the invention, the membranes are hydrophobic membranes that are treated with one or more polymeric wetting agents to render the membranes substantially hydrophilic, followed by treatment with one or more charge-modifying agents, the agents causing the membranes to possess a fixed formal positive charge. In another major aspect of the invention, a cationic membrane is formed from casting in a film a mixed polymer solution comprising a sulfone polymer and a copolymer of vinylpyrrolidone and a cationic imidazolinium compound, and quenching the film in an aqueous bath to produce a coagulated membrane. The membrane can be further cationically charge-modified with one or more charge-modifying agents.

Abstract: It is an object of the present invention to provide a microporous polyolefin membrane, high in pin puncture strength, adequate in pore diameter and high in porosity, comprising (A) an ultra-high-molecular-weight polyolefin having a weight-average molecular weight of 5×105 or more, or (B) a composition containing an ultra-high-molecular-weight polyolefin having a weight-average molecular weight of 5×105 or more, and having a porosity of 30 to 95%, bubble point exceeding 980 KPa and pin puncture strength of 4,900 mN/25 &mgr;m or more. The membrane can be used as a filter or as a separator for a battery.

Abstract: A pore plugging material, for pH dependent membrane diffusion, in which cyclic olefins having phosphazene-functional moieties provide predictable erosion properties when used to plug pores in separation barriers and other porous membranes. Specific properties of the polymers are dependent on several factors, including molecular weight and identity of side groups attached to the phosphazene moiety. However, as a class, phosphazene-functional cyclic olefins provide both predictable erodibility and uniformly benign hydrolysis products and are, therefore, uniquely suitable as pore plugging polymers for separation barriers and membranes of all kinds. The invention, therefore, embraces the provision of a pH-sensitive erodible pore plugging material for pores in separation barriers and membranes of all kinds.

Abstract: Semipermeable porous membranes having an average pore diameter in the range 0.01-3 &mgr;m, and porosity in the range 30%-90%, based on semi-crystalline fluoropolymers and the respective preparation process, wherein the semi-crystalline fluoropolymers comprise: (a) from 10 to 70% by moles of ethylene, (b) from 30 to 90% by moles of a fluorinated monomer selected from tetrafluoroethylene, chlorotrifluoroethylene, or mixtures thereof, (c) from 0.1 to 30% by moles, with respect to the total amount of monomers (a) and (b), of a hydrogenated monomer of formula: CH2═CH—(CH2)n—R1  (I) wherein R1=—OR2, or —(O)tC(O)pR2 wherein t and p are integers equal to 0.

Abstract: Cast semi-permeable membranes made from synthetic polymer used in reverse osmosis, ultrafiltration and microfiltration are treated with a non-leaching antimicrobial agent to prevent its bio-fouling and bacterial breakthrough. The semi-permeable membranes include a polymeric material and a non-leaching antimicrobial agent that is incorporated into and homogeneously distributed throughout the polymeric material. The polymeric material, in the case of one membrane, may be cellulose acetate. In the case of thin film composite polyamide membranes, the antimicrobial agent is incorporated in a microporous polysulfone layer that is sandwiched between a reinforcing fabric and an ultrathin polyamide material. The invention also includes a treatment of flat and hollow fiber semipermeable membranes made with polysulfones and polyvinylidene fluoride.

Abstract: The present invention relates to polymer membranes for separating olefins from paraffins which have the similar molecular size and close boiling point. More particularly, it relates to a silver salt-containing facilitated transport membrane for olefin separation, and also a method for producing the same. An object of the present invention is to provide a silver salt-containing facilitated transport membrane for olefin separation having improved stability, and also a method for preparing the same, which exhibits no deterioration in membrane performance even when operated for an extended period of time.

Abstract: Sulfonic acid group-containing polyvinyl alcohol having crosslinked structures, which is obtained by heat treating a mixed solution of polyvinyl alcohol, a sulfonating agent and a crosslinking agent, a composite polymer membrane excellent in proton conductivity and methanol barrier property, which is obtained by applying the mixed solution to a water-absorptive or hydrophilic polymer membrane, followed by sulfonation and crosslinking, and an electrode for a fuel cell excellent in catalytic activity, which comprises sulfonic acid group-containing polyvinyl alcohol having crosslinked structures and fine catalyst particles carried on porous particles.

Abstract: The present invention provides a composite membrane comprising a porous support layer and a selective layer comprising a vinylacetate polymer. The invention also provides a process for preparing a vinylacetate polymer selective layer on a porous support by depositing a colloidal dispersion having colloid particles of the vinylacetate polymer on the porous support followed by annealing the deposited colloids to form a selective layer. The membranes are useful for separation of gas or liquid or vapor mixtures.

Abstract: A three zone, reinforced, continuous, geometrically symmetrical microporous membrane including a porous support material encapsulated within a middle zone disposed between an upper zone and a lower zone wherein at least one of the three zones has a pore size at least about twenty (20%) percent different than the pore size of the other two zones is disclosed. Apparatus and methods for fabricating three zone reinforced, continuous, geometrically symmetrical, microporous membrane are also disclosed.

Abstract: The invention concerns a filter material characterized in that it is impregnated with an amphiphilic substance or with a hydrophilic and a hydrophobic substance to control the water wettability and water absorption.

Abstract: An asymmetric support membrane can be prepared by using a phase separation method. The method includes immersing a polymer solvent solution into water. The polymer solution is made by dissolving 15 to 35% by weight of the polymer into a solvent that lets the polymer solution become a gel at a temperature of 0 to 50° C. The solution is then allowed to gel and brought into a final membrane form in water for phase separation and formation of the asymmetric support membrane. The polymer may be poly(vinyl chloride), polyethersulfone, polyetherimide and polyamic(methylester). The solvent is &ggr;-butyrolactone alone as a major solvent or is a mixed solvent with N-methyl-2-pyrrolidone as a cosolvent. The asymmetric support membrane is a porous support membrane of a sponge form having open pores that are connected to one another with a narrow pore size distribution. Thus, the asymmetric support membrane has an improved permeance and mechanical strength.

Abstract: A ceramic-supported polymer membrane is disclosed where a porous ceramic membrane support of average pore size no larger than 500 Å is activated by attaching a vinyl terminated lower alkoxy silane to the surface of the ceramic membrane pores. The resulting membrane retains at least 10 micromoles of the vinyl terminated loweralkoxy silane per square meter of the ceramic membrane surface. A method for optimizing the amount of vinyl loweralkoxy silane reacted with the ceramic support surface is also disclosed. The large amount of vinyl terminated loweralkoxy silane which is chemically bonded to the surface of the ceramic porous support produces activated ceramic membrane support surface which is useful for graft polymerization of vinyl monomers onto the porous ceramic membrane support surface. A vinyl monomer is then graft polymerized onto the activated membrane.

Abstract: Highly asymmetric polymeric membranes with large pores which yield bubble points in the range of 0.5 to 25 psid and superior flow characteristics. The membranes can be cast from both metastable dispersions and from homogenous casting formulations. The technique of synthesis involves exposure of the cast membrane to humid air to create large surface pores on the exposed side.

Abstract: An at least two zone, unsupported, continuous microporous membrane is disclosed. The at least two zone, unsupported, continuous microporous membrane may include at least two different membrane pore size zones or the pore sizes may have about the same pore size. Apparatus and processes for fabricating at least a two zone unsupported, continuous, microporous membrane are also disclosed.

Abstract: Provided are a polysulfone type blood-purifying membrane which is improved in blood compatibility and separation properties and less in polyvinyl pyrrolidone eluting in the internal surface of the hollow fiber membrane, as well as a process for producing the same.

Abstract: Water- and ion-conducting membranes composed of sulfonated statistical arylvinyl polymers, the arylvinyl polymer comprising at least one arylvinyl monomer and at least one olefin monomer and wherein aromatic moieties derived from the arylvinyl monomer are at least partially sulfonated, are used as proton-conducting membranes for production of electricity, as water-conducting membranes for humidification of fuel gases in fuel cells and heat and moisture exchange in heating/ventilation/air conditioning systems. Water-conducting membranes composed of sulfonated arylvinyl polymers, the arylvinyl polymer comprising at least one arylvinyl monomer and wherein aromatic moieties derived from the arylvinyl monomer are at least partially sulfonated are used for desalination of seawater.

Abstract: A composite polyamide reverse osmosis membrane and method of producing same. In one embodiment, the membrane is made by coating a porous polysulfone support for about 40 seconds with an aqueous solution containing (i) a polyfunctional amine in the form of 2 wt % of meta-phenylenediamine (MPD), (ii) a polar solvent in the form of 0.3 wt % 2-ethyl-1,3-hexanediol (EHD), and (iii) an amine salt-forming combination of 2.3 wt % camphorsulfonic acid (CSA) and 1.1 wt % triethylamine (TEA). Next, the excess aqueous solution is removed, and the coated support is dipped for about 1 minute in a 0.1 wt % organic solvent solution of trimesoyl chloride (TMC) in a mixture of alkanes having from 8 to 12 carbon atoms. After draining the organic solvent solution off, the resulting composite membrane is heated at 90° C. for about 3.5 minutes and then rinsed in a 0.2% Na2CO3 aqueous solution at room temperature. The resultant membrane exhibits a flux of 47.9 gfd and a salt rejection of 97.

Abstract: Membrane materials for removing uremic toxins from a hydrophobic polymer such as polysulfone and two polyvinyl pyrrolidones, hydrophilic polymers of different molecular weights, that is 10-50 wt. % of a low molecular weight component (molecular weight<100,000) and 90-50 wt. % of a high molecular weight component (molecular weight≧100,000). The membranes are permselective useful in dialysis. The membrane material may have an overall mass transfer coefficient (K0), for a Strokes' radius of at least 30 Å (as determined by a diffusion test during dextran), of ≧0.0025 cm/min and a permeability to albumin of ≦4%.

Abstract: An asymmetric membrane comprising a tubular polymer film in combination with a tubular braid on which the film is supported, requires the braid be macroporous and flexible, yet sufficiently strong to withstand continuous flexing, stretching and abrasion during use for microfiltration (MF) or ultrafiltration (UF). The specifications for a braid of a long-lived membrane are provided. A membrane is formed by supporting a polymer film in which particles of calcined &agr;-alumina are dispersed, on the defined tubular braid.

Abstract: There is disclosed a fibrous sheet using a modified polyvinyl alcohol as a binder with which an aqueous solution containing a water-soluble organic salt, water-soluble inorganic salt and/or water-soluble boron compound is impregnated whereby wet strength of the fibrous sheet can be maintained. The fibrous sheet thus obtained is excellent in water-disintegratability and strength, and its water-disintegratability and strength are not lowered even at high temperatures. Furthermore, it is excellent in water-disintegratability even in cold water.

Abstract: A porous material is disclosed, made of a semi IPN type polymer alloy of a crosslinked polymer (A) obtained by the crosslinking polymerization of a crosslinking-polymerizable vinyl monomer and/or oligomer (a) with a non-crosslinked polymer (D) which is soluble in a solvent (B) capable of dissolving said monomer and/or oligomer (a) therein and subjecting said crosslinked polymer (A) to gelation but is insoluble in a coagulating solution (C) which is compatible with said solvent (B) but doesn't subject said crosslinked polymer (D) to gelation. A porous material excellent in mechanical strength as well as in heat resistance can be prepared. Various functional groups can be introduced into the surface of the porous material. Further, the pore diameter can be easily controlled.

Abstract: A porous hollow fiber polyvinylidene fluoride resin membrane, characterized in that the membrane has a unitary three-dimensional network structure entirely composed of a polyvinylidene fluoride resin and has an inside diameter of 1.5-5 mm and a wall thickness of 0.5-2 mm and in that the relationship between membrane bubble point and water flux per unit wall thickness is on or above the curve shown in FIG. 1.

Abstract: A hollow fiber membrane made of an ethylene-vinyl alcohol polymer, comprising a dense layer existing in the inner surface and a porous layer existing in the layer other than the dense layer, wherein the hollow fiber membrane has a porosity of 60 to 90%, an overall mass transfer coefficient for myoglobin in a water-based system of not less than 0.003 cm/min., and a rejection rate for albumin in a bovine blood system of not less than 97%. The EVA hollow fiber membrane is useful for hemopurification membranes such as hemodialysis membranes, hemodiafiltration membranes, hemofiltration membranes and continuous hemofiltration membranes, and a process for producing the same.

Abstract: Nonwoven webs in accordance with the present invention include multicomponent fibers bonded by a multiplicity of bond sites to form a coherent web. The multicomponent fibers include a first component formed of a hydrophobic polypropylene and a second component formed of a blend of a hydrophobic polyolefin and a hydrophilic melt additive. This second component is disposed at the surface of the fibers. The hydrophilic melt additive-modified polyolefin component can be arranged in various configurations in the cross-section of the fiber and the fibers can have various cross sections. For example, the hydrophilic component can occupy a portion of the surface of the fiber, as would occur for example with a side-by-side or segmented pie multicomponent fiber configuration. Alternatively, the modified hydrophilic polyolefin can occupy substantially the entire surface of fiber, as for example by producing the fibers in a sheath core configuration with the hydrophilic modified component forming the sheath.

Abstract: It is an object of the present invention to provide a microporous polyolefin membrane, high in elongation and porosity, low in shrinkage, and capable of improving battery characteristics, safety and productivity, when used for battery separators. The microporous polyolefin membrane of the present invention comprises (A) an ultra-high-molecular-weight polyolefin having a weight-average molecular weight of 5×105 or more, or (B) a composition containing an ultra-high-molecular-weight polyolefin having a weight-average molecular weight of 5×105 or more, and having a porosity of 45 to 95%, elongation at break of 300% or more, bubble point exceeding 980 KPa and thermal shrinkage in the TD direction of 3% or less. The present invention also provides a method for producing the above microporous polyolefin membrane.

Abstract: The present invention relates to produce a polysulfone based hollow fiber membrane, having high water permeable coefficient and excellent permeability with no deterioration of separation capability, characterized by using an internal coagulating liquid and/or an external coagulating liquid containing diethylene glycol(DEG) and/or salt which can form a hydrate in the process of producing the polysulfone based hollow fiber membrane by following steps: (a) Extrude a spinning dope comprising polysulfones resin, organic solvent and polyvinyl pyrrolydone(PVP) into air through a biannular spinning nozzle to obtain an extrudate in the form of a hollow fiber, (b) Simultaneously inject an internal coagulating liquid into the biannular spinning nozzle at inside bore thereof, and (c) Subsequently introduce said extrudate to an external coagulating liquid.

Abstract: A method for casting-in-place composite and/or non-filled structures which are useful as sorptive or reactive media or for size-based separations. Any particular housing size or configuration can be used, and the inclusion of a large amount of adsorptive particles in polymer is achieved while still maintaining the membrane three dimensional structure. In a first preferred embodiment, the composite structures comprise particles entrapped within a porous polymeric substrate, and are cast in-place into a housing such as a pipette tip, thereby providing an effective platform for micromass handling. With the appropriate selection of particle chemistry, virtually any separation or purification operation can be conducted, including selective bind/elute chromatography operations, on sample mass loads less than 1 microgram in volumes of a few microliters, as well as larger mass loads and volumes. The present invention also encompasses the composite structures as well as sample preparation devices containing the same.