Abstract: A novel expandable composition and method for using the same are disclosed. The disclosed method relates to using the composition, for example, as an automotive cavity sealant. The inventive composition normally is a combination of at least one base polymer, at least one expansion or blowing agents, at least one hydrocarbon resin, at least one curing agent or catalyst and optionally at least one additives such as a supplemental polymer, colorant, tackifier, processing oil, among others.

Abstract: The invention, in one aspect, provides a strip for tear collection. The strip has a first end and an opposite second end and preferably has substantially uniform cross-sections from the first end to the second end. The strip is made of a hydrogel material in substantially dry state. The strip is characterized by having a substantially uniform swelling along the hydrogel strip from the first end to the second end when fully wicked by a tear fluid and by having a correlation between the volume of tear uptake by said strip and the length of the wicked end portion of said strip. A strip of the invention is useful for assay of an analyte of interest in a tear fluid. The invention also provides a method and kits for assaying an analyte of interest (e.g., lactoferrin, glucose, herpes simplex virus, hormones, etc.).

Abstract: The present invention relates to a process for preparing a water-soluble foam matrix which is capable of delivering an active ingredient and articles of manufacture comprising said foam matrix, said article comprising: i) a water-soluble polymeric component in the form of a foam matrix; and ii) an active ingredient component dispersed throughout said matrix; said process comprising the steps of: a) admixing a water-soluble polymer and an active ingredient to form a homogeneous admixture, said admixture having a viscosity of at least 150 Pa-sec; b) introducing a gas or a compound capable of releasing a gas into said admixture to form a foam matrix; and c) optionally, shaping said matrix to provide a matrix having a shape or a form.

Abstract: The present invention relates to foam components comprising polymeric material and an active ingredient, such as detergent ingredients, which are to be delivered to aqueous environment. Highly preferred active ingredients include enzymes. The foam component is stable upon contact with air but dissolves, disintegrates or disperses in water. The invention also relates to compositions containing the foam components and methods for making the foam components.

Abstract: Reinforced, laminated, impregnated, and materials with composite properties as cross linked polyvinyl alcohol hydrogel structures in bulk or cellular matrix forms that can take essentially any physical shape, or can have essentially any size, degree of porosity and surface texture. They have a wide range of physical properties, unusual and unique combinations of physical properties and unique responses to stress fields, which allows for their use in many end use applications.

Abstract: An organic porous material having a continuous pore structure, which comprises interconnected macropores and mesopores with a radius of 0.01 to 100 ?m in the walls of the macropores, having a total pore volume of 1 to 50 ml/g and having pore distribution curve characteristics wherein the value obtained by dividing the half-width of the pore distribution curve at the main peak by the radius at the main peak is 0.5 or less. The organic porous material is useful as an adsorbent having high physical strength and excelling in adsorption amount and adsorption speed, an ion exchanger excelling in durability against swelling and shrinkage, and a filler for chromatography exhibiting high separation capability.

Abstract: The invention relates to methods for preparing a syntactic foam composition suitable for use as a carrier for chemicals or other compounds, including pharmaceuticals. The invention further relates to compositions prepared in accordance with the methods of the present invention.

Abstract: Disclosed are formulations adapted to form a foamed cementitious composition, the foamed cementitious composition itself, a method of forming a hydraulic binder foam, and a method of conveying and applying the resulting foam to a substrate. A pumpable cementitious slurry is formed, the slurry is mixed with a gas such as air, and is subjected to mechanically created turbulence to generate gas bubbles and create a foam, which preferably is stabilized by a foam stabilizing agent such as polyvinyl alcohol present in the slurry. The foam is then conveyed to a nozzle or other suitable dispense point from which it is applied, for example sprayed, preferably uniformly, onto a substrate to be coated. Prior to dispensing, a set accelerator is preferably injected, which causes the foam to gel, which in turn improves the hangability of the product on a substrate. The spray material adheres to the substrate and hardens to form an insulative coating on the substrate.

Abstract: Disclosed are formulations adapted to form a foamed cementitious composition, the foamed cementitious composition itself, a method of forming a hydraulic binder foam, and a method of conveying and applying the resulting foam to a substrate. A pumpable cementitious slurry is formed, the slurry is mixed with a gas such as air, and is subjected to mechanically created turbulence to generate gas bubbles and create a foam, which preferably is stabilized by a foam stabilizing agent such as polyvinyl alcohol present in the slurry. The foam is then conveyed to a nozzle or other suitable dispense point from which it is applied, for example sprayed, preferably uniformly, onto a substrate to be coated. Prior to dispensing, a set accelerator is preferably injected, which causes the foam to gel, which in turn improves the hangability of the product on a substrate. The spray material adheres to the substrate and hardens to form an insulative coating on the substrate.

Abstract: Disclosed are formulations adapted to form a foamed cementitious composition, the foamed cementitious composition itself, a method of forming a hydraulic binder foam, and a method of conveying and applying the resulting foam to a substrate. A pumpable cementitious slurry is formed, the slurry is mixed with a gas such as air, and is subjected to mechanically created turbulence to generate gas bubbles and create a foam, which preferably is stabilized by a foam stabilizing agent such as polyvinyl alcohol present in the slurry. The foam is then conveyed to a nozzle or other suitable dispense point from which it is applied, for example sprayed, preferably uniformly, onto a substrate to be coated. Prior to dispensing, a set accelerator is preferably injected, which causes the foam to gel, which in turn improves the hangability of the product on a substrate. The spray material adheres to the substrate and hardens to form an insulative coating on the substrate.

Abstract: A pre-applied, remoistenable foamed adhesive useful in bonding substrates together.

Abstract: The present invention relates to a process for preparing a water-soluble foam matrix which is capable of delivering an active ingredient and articles of manufacture comprising said foam matrix, said article comprising:

Abstract: A method is provided for preparing a novel therapeutic agent-containing reservoir (26, 28) for use in conjunction with an electrotransport drug delivery system (10). A polymeric matrix is foamed in a selected atmosphere and then cross-linked to form a polymeric closed-cell foam matrix reservoir (26, 28). The method enables relatively smaller quantities of therapeutic agent to be loaded into the electrotransport system (10) and is especially useful for the transdermal delivery of more costly drugs, such as peptides and proteins produced from genetically engineered cell lines, and/or highly potent drugs for which a small dosage is efficacious. Reservoirs (26, 28) prepared according to this method and electrotransport devices (10) containing such reservoirs are also provided.

Abstract: What is disclosed herein are physically cross-linked, cellular hydrogels and methods for their preparation. The cellular materials are highly resilient, hydrophilic materials having broad uses. The cellular materials are prepared by the physical crosslinking of frothed polymers and providing materials that have cellular pores provided by the use of removable materials during the formation of the cellular materials.

Abstract: Polymers comprising fluorinated vinyl alcohol units and having acid labile groups partially introduced are novel. Using such polymers, resist compositions featuring transparency to excimer laser light and alkali solubility are obtained.

Abstract: A method of manufacturing a porous matrix-type drug delivery system is provided. It comprises the steps of: dispersing, stirring, and emulsifying an aqueous solution of a drug in an organic solvent having a polymer compound and a surface active agent solved therein; thereafter forming it into a desirable matrix shape; lyophilizing or drying it at a low temperature or room temperature until the matrix surface is hardened; and drying it again in order to remove the water and the organic solvent.

Abstract: The present invention relates to a process for preparing a water-soluble foam matrix which is capable of delivering an active ingredient and articles of manufacture comprising said foam matrix, said article comprising:

Abstract: A foamable binder composition and methods for producing the same are provided. The foamable binder composition of the present invention comprises a corrosion preventing agent, a main adhesion material, a surfactant capable of inducing formation of foams, and water. In addition, a fast wet tack material may also be present. In one application, the foamable binder composition is used with insulating materials in thermally insulating a building.

Abstract: The invention is directed to methods of making novel porous and solid polyvinyl alcohol hydrogels. These hydrogels are particularly suited for use in the replacement and augmentation of soft tissue or non-load bearing bone of the face, head and cranium.

Abstract: Nasal, sinus and otic packings exhibiting a less adherent surface when in contact with tissue and being less traumatic on removal are prepared. In a first embodiment, polyvinyl acetal foamed packing material undergoes a surface modification imparting a non-adherent hydrogel coated surface. The surface modification is accomplished after final processing and fabrication of the packing product shape. The packing material is subjected to either an atomized spray of an aqueous solution of ethyl alcohol or a polyvinyl acetate/polyvinyl alcohol copolymer. In another embodiment, a foamed polyvinyl acetal material is produced by crosslinking polyvinyl alcohol with an organic compound containing two hydroxyl reactive groups in the presence of an inert gas. An aqueous solution containing polyvinylpyrrolidone is mixed into the reaction during crosslinking.

Abstract: Nasal, sinus and otic packings exhibiting a less adherent surface when in contact with tissue and being less traumatic on removal are prepared. In a first embodiment, polyvinyl acetal foamed packing material undergoes a surface modification imparting a non-adherent hydrogel coated surface. The surface modification is accomplished after final processing and fabrication of the packing product shape. The packing material is subjected to either an atomized spray of an aqueous solution of ethyl alcohol or a polyvinyl acetate/polyvinyl alcohol copolymer. In another embodiment, a foamed polyvinyl acetal material is produced by crosslinking polyvinyl alcohol with an organic compound containing two hydroxyl reactive groups in the presence of an inert gas. An aqueous solution containing polyvinylpyrrolidone is mixed into the reaction during crosslinking.

Abstract: The present invention relates to porous crosslinked polymeric microbeads having cavities joined by interconnecting pores wherein at least some of the cavities at the interior of each microbead communicate with the surface of the microbead. The present invention also relates to a process for producing a porous, crosslinked polymeric microbead as well as the product of this process. This process involves combining an oil phase with an aqueous discontinuous phase to form an emulsion, adding the emulsion to an aqueous suspension medium to form an oil-in-water suspension of dispersed emulsion droplets, and polymerizing the emulsion droplets to form microbeads. At least 10% of the microbeads produced in accordance with the present invention are substantially spherical or substantially ellipsoidal or a combination of the two.

Abstract: This invention relates to a foamed material for fireproofing and/or insulating purposes, consisting of 30 to 90 parts by weight of a solution that contains 20 to 70 wt-% Al (H.sub.2 PO.sub.4).sub.3 and 30 to 80 wt-% water, 5 to 55 parts by weight of a mixture that contains 10 to 70 wt-% MgO, 0 to 70 wt-% mica, 0 to 70 wt-% aluminium hydroxide and 1 to 20 wt-% MnO.sub.2, as well as 1 to 30 parts by weight of a foaming agent that contains 3 to 33 wt-% H.sub.2 O.sub.2 and 67 to 97 wt-% water. In accordance with the invention, the term "insulating purposes" refers to the use of the inventive foamed material for heat and sound insulation.

Abstract: A water content of a water-containing gel of a hydrophilic cross-linked polymer is reduced by pressuring (calendaring) it. Then, a gel composition including, for example, a water-containing gel including cross-linked poly(meth)acrylic acid (salt), glycerol (polyhydric alcohol) and polyester fibers (auxiliary forming material), etc., is fed to a drum dryer on an upstream side of a pressurizing roller. Then, the resulting gel composition is pressurized (calendared) heated by a pressurizing roller to be formed into a sheet. As a result, a sheet-like absorbent material having at least one smooth surface can be obtained. The absorbent material resulting from the described method shows excellent properties and especially absorbing properties such as absorbing rate, absorbency under load, and shape retaining properties.

Abstract: A microporous shaped article is provided. The article comprises ethylene-vinyl alcohol copolymer which has an internal structure of a multiplicity of spaced, randomly dispersed, non-uniform shaped particles of ethylene-vinyl alcohol copolymer.

Abstract: Disclosed is a process for preparing an absorbent foam. The process generally comprises forming a solution of a polymer in a solvent, freezing the solution at a relatively slow cooling rate to a temperature below the freezing point of the solvent, removing the solvent from the frozen solution, and recovering the polymer to form a water-swellable, water-insoluble polymeric foam. The process has been found to enable one to prepare an absorbent foam that exhibits desirable softness and flexibility properties yet is highly absorbent. Such an absorbent foam may be used in a disposable absorbent product intended for the absorption of fluids such as body fluids.

Abstract: The present invention relates to porous crosslinked polymeric microbeads having cavities joined by interconnecting pores wherein at least some of the cavities at the interior of each microbead communicate with the surface of the microbead. The present invention also relates to a process for producing a porous, crosslinked polymeric microbead as well as the product of this process. This process involves combining an oil phase with an aqueous discontinuous phase to form an emulsion, adding the emulsion to an aqueous suspension medium to form an oil-in-water suspension of dispersed emulsion droplets, and polymerizing the emulsion droplets to form microbeads. At least 10% of the microbeads produced in accordance with the present invention are substantially spherical or substantially ellipsoidal or a combination of the two.

Abstract: A germicidal absorptive material for use in surgical packings, sanitary tampons and similar uses is provided by a sponge-like matrix of polyvinyl alcohol-acetal copolymer to which is tightly bound a germicidal disinfectant dye. Polyvinyl alcohol-acetal polymer shows exceptional avidity for a number of disinfectant dyes, both acidic and basic, such as methylene blue and gentian violet. Consequently, sponges of this material containing disinfectant dye release no dye to an aqueous solution The material is generally a porous matrix that releases no particles or fines into wounds or body orifices. Presence of bound disinfectant dye allows the sponge to inhibit bacterial growth in a number of different situations. Several common bacteria are killed by being incubated in the present of an embodiment of the invention which contains both methylene blue and gentian violet.

Abstract: Biodegradable foamed plastic material having a bulk density comprised within the range of from 5 to 13 kg/m.sup.3, comprising:30-99.5 by weight of polisaccharide containing more than 50% of thermoplastic starch or starch complexed by polimeric structures, having an intrinsic viscosity (in DMSO) lower than 1.3 dl/g and less than 20% by weight of soluble fraction in ethanol;0.5-70% by weight of a thermoplastic polymer which is soluble in starch, or is capable of complexing it;0-20% by weight of water.The material can be used as a loose filler or for other foamed articles.

Abstract: A resin composition for low expansion moldings which comprises (A) 20 to 80 parts by weight of a vinyl chloride resin having an average degree of polymerization of from 500 to 1700 and (B) correspondingly from 80 to 20 parts by weight of a copolymer made of 60 to 90 parts by weight a polymerizable monomer mixture consisting of 20 to 40 wt % of acrylonitrile, 20 to 60 wt % of .alpha.-methylstyrene and 20 to 40 wt % of styrene and, correspondingly, 40 to 10 parts by weight of a crosslinked acrylic rubber. The resin composition further comprises (C) 0.5 to 30 parts by weight of an acrylic resin having a reduced viscosity of not less than 3.0 dl/g when measured by use of a chloroform solution of the acrylic resin at a concentration of 0.1 g/100 ml, (D) 0.1 to 10 parts by weight of a thermally decomposable rosining agent, and (E) from 1 to 10 parts by weight of a stabilizer, each based on 100 parts by weight of a mixture of the components (A) and (B).

Abstract: A hydrophilic polymer alloy which has a permanent hydrophilic nature, a sufficient mechanical strength and a high safety and which is suitable for the formation of hydrophilic porous membranes manufacturable by an industrially advantageous process can be prepared by blending an amorphous hydrophilic copolymer (X) containing 10 mole % or more of an ethylene unit, 10 to 60 mole % of a vinyl alcohol unit and 1 mole % or more of a vinyl acetate unit with a polyolefin (Y). Furthermore, this polymer alloy is also suitable for the formation of hydrophilic (porous) fibers having a sufficient mechanical strength and antistatic function.

Abstract: A foamed plastic manufactured by foaming a mixture of a resin and a volatile polymerizable foaming agent, wherein the pressure in the foams of the foamed plastic is less than atmospheric pressure, is disclosed. Further, a foamed plastic manufactured by hermetically sealing with an airtight film and foaming a mixture of a resin and a volatile polymerizable foaming agent, wherein the pressure in a gap region between the airtight film and the foamed plastic and the pressure in the foams of the foamed plastic are less than atmospheric pressure is disclosed. Further, a method of manufacturing foamed plastic comprising foaming a mixture of a volatile polymerizable foaming agent and a resin, and irradiating the foamed plastic with an energy beam.

Abstract: A molded porous polyvinyl alcohol sponge includes an outer skin capable of absorbing and passing water to interior portions of the sponge, and is substantially smooth except for predetermined structural details imparted by the mold used in its making. The outer skin has smaller average pore size than does the interior portion of the product.

Abstract: A molded porous polyvinyl alcohol sponge includes an outer skin capable of absorbing and passing water to interior portions of the sponge, and is substantially smooth except for predetermined structural details imparted by the mold used in its making. The outer skin has smaller average pore size than does the interior portion of the product.

Abstract: A process for making a crosslinked, highly porous body derived from a water-soluble, hydrogel polymer, wherein the porous body is characterized in that it has an open-celled 3-dimensional lattice structure, a density of less than about 1.0 g/cm.sup.3, a surface area of equal to or greater than about 30 m.sup.2 /g, and a compression strength of equal to or less than about 75% yield at 300 psi.

Abstract: A crosslinked, highly porous body derived from a water-soluble, hydrogel polymer, wherein the porous body is characterized in that it has an open-celled 3-dimensional lattice structure, a density of less than about 1.0 g/cm.sup.3 a surface area of equal to or greater than about 30 m.sup.2 /g, a compression strength of equal to or less than about 10% yield at 10 psi, and an average pore diameter of less than about 1000 Angstroms.When the hydrogel polymer used is guar gum, the resulting product is particularly useful for thermal insulation applications.

Abstract: An ultra-low density, microcellular open-celled polymer foam and a method for making such foam. A polymer is dissolved in a heated solution consisting essentially of at least one solvent for the dissolution of the polymer in the heated solution and the phase inversion of the dissolved polymer to a liquid gel upon sufficient cooling of the heated solution. The heated solution is contained in a containment means provided with a nucleating promoting means having a relatively rough surface formed of fixed nucleating sites. The heated solution is cooled for a period of time sufficient to form a liquid gel of the polymer by phase inversion. From the gel, a porous foam having a density of less than about 12.0 mg/cm.sup.3 and open porosity provided by well interconnected strut morphology is formed.

Abstract: A crosslinked, highly porous body derived from a water-soluble, hydrogel polymer, wherein the porous body is characterized in that it has an open-celled 3-dimensional lattice structure, a density of less than about 1.0 g/cm.sup.3, a surface area of equal to or greater than about 30 m.sup.2 /g, and a compression strength of equal to or less than about 75% yield at 300 psi.

Abstract: A foamed plastic manufactured by foaming a mixture of a resin and a volatile polymerizable foaming agent, wherein the pressure in the foams of the foamed plastic is less than atmospheric pressure, is disclosed. Further, a foamed plastic manufactured by hermetically sealing with an airtight film and foaming a mixture of a resin and a volatile polymerizable foaming agent, wherein the pressure in a gap region between the airtight film and the foamed plastic and the pressure in the foams of the foamed plastic are less than atmospheric pressure is disclosed. Further, a method of manufacturing foamed plastic comprising foaming a mixture of a volatile polymerizable foaming agent and a resin, and irradiating the foamed plastic with an energy beam.

Abstract: A compostable, biodegradable foam core board has a facing sheet adhered to a foam core sheet made of a foamable biodegradable material selected from a polyvinyl alcohol polymer, a starch-based thermoplastic polymer, a polylactic acid polymer, and other foamable, biodegradable polymers having structural rigidity when foamed. The foam core sheet has selected structural properties including a foam core weight in a preferred range of 30 to 50 lbs/msf, a foam density in a preferred range of 1.5 to 9 lbs/ft.sup.3, and a foam cell size in a preferred range of 0.30 to 0.70 mm. In one example, the foam core material is composed of a mixture of a polyvinyl alcohol polymer and high-melt-index polystyrene as a structural polymer additive. In another preferred example, the foam core material contains a blend of destructurized starch, polyethylene, polyvinyl alcohol, polyvinyl acetate, and glycerol as a plasticizer.

Abstract: Flexible, porous, absorbent polymeric macrostructures having flexibility even after extended periods at elevated temperatures and/or low humidities are disclosed. The macrostructure comprises an interparticle crosslinked aggregate and an effective amount of a suitable plasticizer. The macrostructures are suitable for use, for example, in disposable absorbent articles such as diapers.

Abstract: A process for producing a biodegradable resin foam, having the steps of mixing a starch polymer containing from 5% by weight to 30% by weight of water, a vinyl alcohol resin containing from 5% by weight to 30% by weight of water, a nonionic surfactant, an inorganic or organic filler, and optionally a thickening agent; optionally adjusting the water content of the mixture, to prepare a composition having from 5% by weight to 30% by weight of water on the whole, based on total weight of the composition; melting and expanding it to prepare a foam, which has a low density and fine closed cells, and shows a good surface condition in a molded body.

Abstract: A method to prepare uniform populations of macroscopic beads containing pores of at least 0.1 microns diameter is described. The beads consist essentially of a copolymer of a monoethylenically unsaturated monomer and a crosslinking polyethylenically unsaturated monomer, said resulting copolymer optionally being derivatized with functional groups, linking moieties, and/or affinity ligands. The macroporous beads are obtained by utilizing, as porogen in the polymerization reaction, porous inorganic particles which have been preabsorbed with a blowing agent. The blowing agent is not activated until after the polymerization takes place; when the blowing agent is activated, the organic polymer which isolates the inorganic porogen particles from each other in the bead is destroyed. Upon subsequent dissolution of the inorganic porogen, a network of pores throughout the organic copolymer-formed particle is formed. The resulting beads are useful in a variety of chromatographic, analytical and biomedical techniques.

Abstract: A process for producing a foamed polyvinyl alcohol film, which comprises mechanically foaming an aqueous solution containing a polyvinyl alcohol and a plasticizer, coating the foamed solution on the substrate, followed by heat-drying.

Abstract: Hydrogel foamsa) based on gelatin and water,b) optionally containing polyvinyl alcohol,c) containing a crosslinking agent selected from the group comprisingca) the compounds of at least trivalent metals or semimetals, for example boric acid, borates, aluminium salts, titanates and alkyl titanates, and/or from the group comprisingcb) organic and/or inorganic acids and/or salts thereof, for example gallic acid, gallates, phosphoric acids, phosphates, dihydroxybenzoic acid and dihydroxybenzoates,d) and optionally containing organic plasticizers, and/or auxiliary agents and/or additives.

Abstract: Thermoplastic compositions of internally plasticized polyvinyl alcohol material and a low molecular weight alcohol are provided that can be extruded into water soluble biodegradable foams. The compositions can be modified to provide foams that have varying degrees of water solubility and a broad range of physical characteristics.

Abstract: An expandable, powder coating composition is disclosed which comprises (a) a thermoplastic resin containing a hydroxyl group-containing polymer, (b) a cross-linking agent containing a polyisocyanate compound which is capable of reacting with the hydroxyl groups of the polymer to crosslink the polymer at a temperature higher than the melting point of the thermoplastic resin and which is solid at room temperature, and (c) a blowing agent capable of decomposing and generating a gas when heated to a temperature higher than the melting point of the thermoplastic resin. Powder coating with the coating composition can give a heat-insulating, foamed sheath or lining over the surface of a metal tube or box to be used in air conditioners.

Abstract: Aesthetically attractive, free standing dispensers for the controlled release of volatile liquid materials such as perfumes and fragrances into the atmosphere are prepared by (1) forming a first solution by heating a mixture comprising polyvinyl alcohol and water and/or dimethyl sulfoxide under atmospheric pressure, (2) adding a second solution comprising a volatile liquid material and a monohydric alcohol in a solvent that is miscible with the first solution under conditions that avoid precipitation of polyvinyl alcohol, and then (3) cooling the resultant solution to below room temperature to form a gel in the shape of the final dispenser. The exterior surfaces of the dispenser remainds dry to the touch throughout its useful life.

Abstract: Aesthetically attractive, free standing dispensers for the controlled release of volatile liquid materials such as perfumes and fragrances into the atmosphere consist essentially of composite hydrogels comprising a continuous phase of a solubilized polyvinyl alcohol, a dispersed phase comprising a polyelectrolyte and an aqueous solution of the volatile liquid that is distributed between said continuous and dispersed phases. The exterior surfaces of the dispenser remain dry to the touch throughout its useful life.

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.