Membrana Gmbh

3M Innovative Properties Company

Celgard Inc.

Em Innovative Properties Company

Oliver Schuster

Friedbert Wechs

Wolfgang Ansorge

Quan Huang

Bodo Von Harten

Arne Gehlen

Richard Kruger

Karl Bauer

Phung Ngoc Duong

Zhengming Zhang

Britta Zimmerer

Ernst Spindler

Richard Krüger

Ngoc-Phung Duong

Martin Rütering

Klaus Dombrowski

Phung Duong

Hydrophobic flat membrane made from a vinylidene fluoride polymer with a wall, a first surface, and a second surface. The membrane has on its first surface a network structure with open pores and on its second surface a continuous skin in which pores are formed, and adjacent to the skin of the second surface a supporting layer with an isotropic pore structure across the wall thickness, wherein the supporting layer extends over at least 80% of the wall thickness and wherein the pores of the supporting layer have an average diameter of less than 1 &#x3bc;m. The weight average of the molecular weight Mof the vinylidene fluoride polymer lies in the range from 300 000 to 500 000 daltons, and the polydispersivity M/Mis greater than 5.5. The pores in the skin of the second surface have a closed perimeter in the plane of the skin and an average ratio of the extension in the direction of the longest axis thereof to the extension in the direction of the shortest axis thereof of at most 5. The pores in the first surface and second surface have an essentially isotropic distribution of their orientation. The porosity of the membrane lies in the range from 50 to 90 vol. % and the wall thickness in the range from 50 to 300 &#x3bc;m. The membrane has a maximum separating pore diameter din the range from 0.05 to 1.5 &#x3bc;m.

Microporous polyvinyl fluoride planar membrane and production thereof

Hydrophobic hollow-fiber membrane made from a vinylidene fluoride polymer with a wall and a wall thickness, an outer surface on its outer side, an inner surface on its inner side and facing its lumen and adjacent to the inner surface a supporting layer having a structure that is substantially isotropic across the wall thickness, the supporting layer extending over at least 80% of the wall thickness and comprising pores having an average diameter of less than 1 &#x3bc;m, and wherein the hollow-fiber membrane has pores on its outer surface and on its inner surface, characterized in that the vinylidene fluoride polymer has a weight-average molecular weight Min the range from 550 000 to 700 000 daltons and a polydispersivity greater than 3.0; the pores in the outer and in the inner surface are formed like islands and have a maximum ratio of their longitudinal extension to the transverse extension of 10; the porosity lies in the range from 50 to 90 vol. %, the wall thickness in the range from 50 to 300 &#x3bc;m, and the diameter of the lumen in the range from 100 to 500 &#x3bc;m; and the hollow-fiber membrane has a maximum separating pore diameter din the range from 0.3 to 0.7 &#x3bc;m, determined according to the bubble point method.

Microporous polyvinylidene fluoride membrane

The invention relates to a hollow-fiber membrane for ultrafiltration made from a hydrophobic aromatic sulfone polymer and at least one hydrophilic polymer, the membrane having an open-pore separating layer on the lumen side, an adjoining supporting layer with asymmetric, sponge-like pore structure without finger pores and an outer layer adjoining the supporting layer towards the outer surface. The separating layer has a cutoff between 20 000 and 200 000 daltons, a thickness of max. 10% of the membrane thickness and an essentially isotropic pore structure. The size of the pores in the supporting layer initially increases up to a zone with maximum pore size, and then decreases towards the outer layer, and the outer layer exhibits a thickness of 10 to 30% of the wall thickness and an essentially isotropic pore structure. The mean size of the pores in the outer layer is larger than in the separating layer, but smaller than in the supporting layer. The wall thickness of the hollow-fiber membrane lies in the range from 100 to 450 &#x3bc;m. The invention relates furthermore to a method for the production of these hollow-fiber membranes.

Ultrafiltration membrane

Method for producing this membrane from a casting solution comprising the hydrophobic first sulfone polymer and the hydrophilic second polymer in a solvent system, the method comprising the steps of pouring the casting solution, conditioned to a molding temperature, onto a carrier to form a film, which carrier has a temperature that is higher in comparison to the molding temperature, conveying the film through a climate-controlled zone, initiating the coagulation in a coagulation bath for the formation of a membrane structure, withdrawing the membrane structure from the carrier with a speed that is increased in comparison to the carrier speed, stabilizing, extracting, and subsequently drying the membrane.

Microfiltration membrane with improved filtration properties

A hydrophilic semipermeable hollow-fiber membrane for blood treatment, with an integrally asymmetric structure based on a synthetic polymer. The hollow-fiber membrane possesses on its inner surface a separating layer and an adjoining open-pored supporting layer, and has an ultrafiltration rate in albumin solution of 5 to 25 ml/(h&#xb7;m&#xb7;mmHg). The hollow-fiber membrane is free from pore-stabilizing additives and has a maximum sieving coefficient for albumin of 0.005 and a sieving coefficient for cytochrome c that satisfies the equationSC&#x2267;5&#xb7;10&#xb7;UFR&#x2212;0.004&#xb7;UFR+1.081&#xb7;UFR&#x2212;0.25.

Dialysis membrane with improved removal of middle molecules

The invention relates to a hydrophobic, integrally asymmetrical hollow-fiber membrane made of a vinylidene fluoride homopolymer or copolymer, wherein the wall of the membrane has a microporous supporting layer having a sponge-like, open-pored, essentially isotropic pore structure without finger pores, the supporting layer extending across at least 90% of the wall thickness and having pores with an average diameter of less than 0.5 &#x3bc;m. The hollow-fiber membrane is characterized in that it has a separating layer adjacent to the supporting layer on its outer surface and that it has an outer surface with a homogeneous, uniform structure without pores, a porosity in the range from 40 to 80 vol. %, a wall thickness from 25 to 100 &#x3bc;m, a diameter of the lumen of the hollow-fiber membrane from 100 to 500 &#x3bc;m, a permeability for nitrogen of at least 25 ml/(cm&#xb7;min&#xb7;bar), and an elongation at break of at least 250%. The invention further relates to a method for producing hollow-fiber membranes of this type.

Hydrophobic ozone-stable membrane made of polyvinylidene fluoride

A hydrophilic, semipermeable hollow-fiber membrane for blood treatment, with an integrally asymmetric structure based on a synthetic polymer. The hollow-fiber membrane possesses on its inner surface a porous separating layer and an open-pored supporting layer adjoining the separating layer, and has an ultrafiltration rate in albumin solution of 25 to 60 ml/(h&#xb7;m&#xb7;mmHg). The hollow-fiber membrane is free from pore-stabilizing additives, and has a minimum sieving coefficient for cytochrome c of 0.8 and maximum sieving coefficient for albumin of 0.005. Method for the preparation of such membranes based on coagulation induced by a non-solvent, whereby a spinning solution of a synthetic first polymer and possibly a hydrophilic second polymer is extruded into a hollow fiber through the annular slit of a hollow-fiber die with simultaneous extrusion of a coagulation medium as the interior filler through the central opening of the hollow-fiber die, the interior filler initiating coagulation in the interior of the hollow fiber as a result of which a separating layer on the inner surface of the hollow-fiber membrane is formed as well as the membrane structure, the method being characterized in that the interior filler contains a polyelectrolyte with negative fixed charges.

High-flux dialysis membrane with an improved separation behaviour

A hydrophilic semipermeable hollow-fibre membrane for blood treatment, with an integrally asymmetric structure based on a synthetic polymer. The hollow-fiber membrane possess on its inner surface a separating layer and an adjoining open-pored supporting layer, and has an ultrafiltration rate in albumin solution of 5 to &#x2266;25 ml/(h&#xb7;m&#xb7;mmHg). The hollow fiber membrane is free from pore-stabilizing additives and has a maximum sieving coefficient for albumin of 0.005 and a sieving coefficient of cytochrome c that satisfies the equation&#x2212;0.25.

Dialysis membrane having improved ability for removal of middle molecules

A direct methanol fuel cell has a proton conducting membrane (PCM), a catalyst in contact with the PCM, a gas diffusion layer in contact with the catalyst, and a conducting plate in contact with the gas diffusion membrane. The gas diffusion layer comprises a microporous membrane. The microporous membrane may be a microporous membrane, a laminate of a microporous membrane, and a skinned microporous membrane.

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Gevelsberg, Germany

Oliver Schuster