Abstract: The invention relates to a process for the removal of components causing turbidity, from a fluid, by means of microfiltration, whereby the fluid is beer, wine, fruit juice, bacterial suspension, blood, milk, enzyme suspension, etc. According to the invention, the fluid to be treated is fed across an asymmetric membrane having a pore structure such that the pores on the feed side of the membrane are larger than the nominal pore size and the pores of nominal pore size occur in the cross section toward the permeate side, the filtered off components are back-flushed from the membrane and are subsequently carried away with the fluid. The nominal pore size is usually 0.1-5.0 .mu.m and preferably 0.2-1.0 .mu.m. The membrane may be tubular, flat or capillary. Back-flushing takes place intermittently with a frequency of 1 second to 10 minutes for 0.1-1 second at a counter pressure of 0.5-5 bar. The feed velocity is preferably below 2 m/s and the pressure difference over the membrane is less than 0.5 bar.

Abstract: The invention relates to a microfiltration and/or ultrafiltration membrane consisting of a polymer having nominal pores of 0.001-10 .mu.m. The special feature of the membranes according to the invention is that the matrix of the membrane incorporates an active adsorbent which is preferably polyvinyl pyrrolidone. Usually the polyvinyl polypyrrolidon is present in the membrane in an amount of 5-90% by weight and preferably in an amount of 30-70% by weight. Preferably the membrane is hydrophilic and is usually asymmetric or is constructed of different layers. The nominal pore size of the membrane is 0N05--5 .mu.m and preferably 0.2-1.0 .mu.m, while the membrane is tubular, flat or capillary.

Abstract: A semi-permeable composite with a porous substrate having a polymer network obtained by interfacial polymerization of a reactive polyfunctional monomer having reactive groups --NHR. (R.sub.1 is H or a C.sub.1 -C.sub.20 alkyl groups), --OH or --SH and a reactive polyfunctional material having --NCO reactive groups built from a polyalkylene oxide with terminal --OH groups and a polyisocyanate, and a process for separating components in an organic liquid medium by using said composite.

Abstract: Semipermeable composite membrane, with a porous carrier substrate, whereby said carrier substrate is provided with a polymer network obtained by polycondensation, especially interfacial polymerization, which is built up of at least one reactive polyfunctional monomer or oligomer or prepolymer or polymer, and at least one acid halide containing polymer.The specialty of this semi-permeable composite membrane consists therein that the acid halide containing polymere itself is built up of one or more vinyl containing monomers.The acid halide containing polymer is generally a copolymer of acryloylchloride H.sub.2 C.dbd.CHCOCl or methacryloyl chloride H.sub.2 C.dbd.C(CH13)COCl with one or more vinyl containing monomers.Usually the vinyl containing monomer is an acrylate or an acrylamide or a mixture thereof.

Abstract: The present invention deals with a process and device for the separation of a body fluid from particulate materials in the fluid to be used for a chemical analysis of the fluid components. The process and device are in particular suitable for the separation of plasma from whole blood. Furthermore the present invention relates to a testing kit for the above mentioned separation and analysis purposes. The device has a collector membrane of defined capacity which intimately contacts the small pore side of a separator membrane having asymmetric pores passing through it permitting the application of a body fluid to the large pore side of the separator membrane.

Abstract: The invention relates to a semi-permeable composite membrane with a porous carrier substrate whereon a polymer network obtained by interfacial polymerization is applied, said network comprises an additional polymer. According to the present invention said additional polymer is dissolved in the water phase or in the organic phase, from which said interfacial polymerization occurs, which additional polymer is molecularly entangled in said network and may regulate in particular the selectivity and the permeability of the composite membrane.Preferably the additional polymer is a non-reactive polymer.Furthermore, the invention relates to a process for manufacturing the above-mentioned semi-permeable membrane.

Abstract: The invention relates to a method for producing a flat porous product, in which a solution of an elastomeric material is deposited on a temporary substrate and the elastomeric material is coagulated on the substrate from the solution with the aid of a nonsolvent, wherein the surface of the substrate has an adhesion to the coagulating elastomer which is such that, after coagulation, the elastomeric flat product can be removed from the substrate without damage and the side (macroporous zone or bottom layer) of the elastomeric flat product facing the substrate possesses pores having a diameter in the region of 20-200 .mu.m and has a porosity of more than 75%, a flat product which can be obtained according to this method for use as wound covering material and a method for treating wounds therewith.

Abstract: The invention relates to a process for preparing a microporous membrane, starting from a mixture of at least a hydrophobic polymer and a hydrophilic polymer, by dissolving these polymers first in a suitable solvent or mixture of solvents and subsequently by coagulating in a coagulation bath. According to the invention a more or less hydrophilic membrane is prepared by removing the membrane so obtained from the coagulation bath and subsequently by leaching at least a part of the hydrophilic polymer from the matrix, alternatively followed by hydrophobization. Said leaching of the hydrophilic polymer occurs by treatment of the membrane with an oxidizing/hydrolizing agent. The invention furthermore comprises microporous membranes, flat or tubular or in the form of hollow fibers, having a good chemical resistance and good mechanical strength.

Abstract: This invention relates to a process for the preparation of hydrophilic membranes by coagulation of a solution of at least one hydrophobic polymer and at least one hydrophilic polymer in a suitable solvent medium in a coagulation medium. The process according to the invention is characterized in that hydrophilic microfiltration and/or ultrafiltration membranes are prepared by cross-linking the hydrophilic polymer which is present in or on the obtained membrane matrix after the coagulation in an essentially non-swollen state and fixing same as such in or on the polymer matrix. Advantageously the solvents and the undesirable components of the coagulation medium are removed whereby the hydrophilic polymer is converted into an essentially non-swollen state prior to cross-linking. The removal of the undesirable components from the membrane takes place by means of a non-solvent for the hydrophilic polymer according to the invention.

Abstract: This invention relates to a process for the preparation of hydrophilic membranes by coagulation of a solution of at least one hydrophobic polymer and at least one hydrophilic polymer in a suitable solvent medium in a coagulation medium. The process according to the invention is characterized in that hydrophilic microfiltration and/or ultrafiltration membranes are prepared by cross-linking the hydrophilic polymer which is present in or on the obtained membrane matrix after the coagulation in an essentially non-swollen state and fixing same as such in or on the polymer matrix. Advantageously the solvents and the undesirable components of the coagulation medium are removed whereby the hydrophilic polymer is converted into an essentially non-swollen state prior to cross-linking. The removal of the undesirable components from the membrane takes place by means of a non-solvent for the hydrophilic polymer according to the invention.