Abstract: A method of forming a consolidated structure. The method comprises placing a thermoplastic material onto a forming tool to form a structure; positioning the structure within a tool; and consolidating the structure to form the consolidated structure. The tool has a number of die liners configured to generate heat in response to a magnetic field. Consolidating comprises applying a magnetic field to the number of die liners to heat the structure to a consolidation temperature.

Abstract: The present invention relates to an external cooling system for a molten film tube produced by a blown film tubular extrusion process. Embodiments of the present disclosure provide a unidirectional cooling element having a unidirectional cooling interface containing a cooling gas deflector spaced adjacent to the molten film tube. The unidirectional cooling element operably expels cooling gas in a path with the flow of the molten film tube toward an exit gap formed between the unidirectional cooling interface and the molten film tube. The minimum gap between the unidirectional cooling interface and the molten film tube occurs at the exit gap, and advantageously, the unidirectional cooling interface is provided with one or more compound angles to maximize stability and cooling efficiency.

Abstract: The invention relates to a film product (10) for packing products, particularly liquids (200), pasty and/or pourable materials, in sealed film packages (100), comprising at least two film layers (20a, 20b), wherein the outwardly facing film layer (20a) is thermally stable, and the inwardly facing film layer (20b) is sealable, and both film layers (20a, 20b) are produced in a water-cooled coextrusion blow molding process.

Abstract: A flexible pipe body and methods of producing a flexible pipe body are disclosed. The method may include providing a tubular length of polymeric material for forming a polymeric layer of flexible pipe body; providing a strength layer radially outwards of the polymeric layer; and treating the polymeric layer with a non-ambient temperature and pressure.

Abstract: An absorbent article including a chassis and a laminate. The chassis has a topsheet side, a backsheet side, and first and second opposing longitudinal edges extending from a rear waist region to an opposing front waist region. The laminate includes a carrier having a first face and a second face and a fastening patch on a portion of the first face of the carrier. The laminate is wrapped around the first longitudinal edge of the chassis in the rear waist region so that the second face of the carrier contacts the topsheet side and the backsheet side of the chassis. The fastening patch includes fastening elements that are exposed on the topsheet side of the chassis. A method of making the absorbent article is also disclosed.

Abstract: After a second liquid is applied to a support and dried, a first liquid is applied thereon. On a film of the first liquid, a third liquid (water) is supplied in droplets using an inkjet-type liquid supply unit. An area supplied with the droplets is referred to as porous area. Next, an organic solvent is evaporated from the film and the droplets are evaporated from the porous area. Thus, a porous film is obtained. The porous film has the porous areas in which a plurality of pores are arranged. Since the droplets are directly formed by an inkjet printing method, a condensation process and a droplet growing process are unnecessary. Thus, the porous film is produced efficiently. Shapes of the porous areas can be changed easily. The porous areas can be formed on the porous film in various patterns.

Abstract: A process and apparatus for multi-shot, liquid-resin-molding of continuous-fiber composite articles is disclosed. The process involves the step-wise fabrication of an article wherein continuity of the fibers is maintained between the multiple workpieces of the finished composite article.

Abstract: A process is disclosed of forming cellulose fibers. The process includes extruding an aqueous solution of cellulose and a solvent through a first member to form filaments. The first member has multiple rows of first and second openings with a nozzle positioned in each of the first openings. At least one of the nozzles in one row is staggered from at least one of the nozzles in an adjacent row. At least a portion of each of the filaments is shrouded in a pressurized gas emitted through each of the first openings. Each of the filaments is contacted with a liquid to remove some of the solvent and transform each of the filaments into a continuous solid fiber. The continuous solid fibers are then collected on a moving surface to form a non-woven cellulose web.

Abstract: A method for making a polymeric web exhibiting a soft and silky tactile impression on at least one side thereof. The method comprises the steps of providing a forming structure being moveable upon a forming drum and comprising a plurality of protrusions extending from the forming structure, the protrusions being generally columnar forms having an average aspect ratio of at least about 1. The forming structure is disposed adjacent a vacuum chamber and vacuum is applied at a sufficient level to induce a sufficient partial pressure to conform a precursor web to the forming structure, thereby forming the polymeric web. The precursor web can be cast directly onto the forming structure, or it can be re-heated by re-heat means to elevate its temperature sufficiently to permit vacuum formation.

Abstract: This invention relates to blown films produced from copolymer made by a process for polymerizing olefins in which the amount of trimethylaluminum in a methylalumoxane solution is adjusted to be from 1 to 25 mol %, prior to use as an activator, where the mol % trimethylaluminum is determined by 1H NMR of the solution prior to combination with any support. This invention also relates to a process for polymerizing olefins in which the amount of an unknown species present in a methylalumoxane solution is adjusted to be from 0.10 to 0.65 integration units prior to use as an activator, where the amount of the unknown species is determined by the 1H NMR spectra of the solution performed prior to combination with any support. Preferably, the methylalumoxane solution is present in a catalyst system also comprising a metallocene transition metal compound.

Abstract: A process and apparatus for multi-shot, liquid-resin-molding of continuous-fiber composite articles is disclosed. The process involves the step-wise fabrication of an article wherein continuity of the fibers is maintained between the multiple workpieces of the finished composite article.

Abstract: A process and apparatus for multi-shot, liquid-resin-molding of continuous-fiber composite articles is disclosed. The process involves the step-wise fabrication of an article wherein continuity of the fibers is maintained between the multiple workpieces of the finished composite article.

Abstract: A devolatilizer nozzle comprising at least one perforated flow tube having a non-circular cross-section. In an embodiment, the non-circular cross-section has equal to or greater than 3 sides. The non-circular cross-section of said nozzle may be a triangle, diamond, pentagon, hexagon, heptagon, or octagon. A majority of the perforations in the flow tube of said nozzle may have a maximum strand angle of equal to or less than 45 degrees. The nozzle may further comprise tapered holes, which may be formed by a water jet. The nozzle may further comprise a plurality of parallel flow tubes. The nozzle may comprise 304 stainless steel, AL-6XN stainless steel, or LDX 2101 stainless steel.

Abstract: A surface for an article has an artificially producible base structure (10). The structure (12) has or develops a capillary effect at which the quotient from capillary work (K) and adhesion work (A) is larger 1. The capillary structures and their capillaries have a negative capillary rise such that liquid is forced from the capillaries, allowing for a self-cleaning effect.

Abstract: The present invention relates to an apparatus and method for cooling material during continuous vacuum forming. The apparatus includes one or more cooling regions positioned adjacent one or more vacuum regions. A rotatable support belt including perforations therein supports a flexible patterned belt. The flexible patterned belt includes apertures spaced along the length and width thereof. The one or more cooling regions provide a cooling fluid to be drawn through the apertures in the flexible patterned belt to form an area of cooling fluid on the flexible patterned belt which contacts a bottom surface of a hot material received on the flexible patterned belt in order to cool the bottom surface of the material and the flexible patterned belt. The vacuum regions are in fluid flow communication with the perforations of the support belt and the apertures of the flexible patterned belt for drawing the material onto the flexible patterned belt.

Abstract: A process is disclosed of forming cellulose fibers. The process includes extruding an aqueous solution of cellulose and a solvent through a first member to form molten filaments. The first member has multiple rows of first and second openings with a nozzle positioned in each of the first openings. At least one of the nozzles in one row is staggered from at least one of the nozzles in an adjacent row. At least a portion of each of the molten filaments is shrouded in a pressurized gas emitted through each of the first openings. Each of the molten filaments is contacted with a liquid to remove some of the solvent and transform each of the molten filaments into a continuous solid fiber. The continuous solid fibers are then collected on a moving surface to form a non-woven cellulose web.

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 ?m.

Abstract: A method for producing abrasive non-woven cloth includes forming a non-woven web of fibers including a first layer adjacent to a first surface of the web containing at least about 5% by weight of thermoplastic fibers. The web is patterned to generate raised regions and lowered regions in the first surface, and then heat treated to cause at least part of the thermoplastic fibers to form nodules, thereby imparting abrasive properties to at least the raised regions of the first surface. The non-woven web preferably includes a second layer adjacent to a second surface of the web made up primarily of fibers which do not form nodules under the heat treatment.

Abstract: The present invention relates to an apparatus and method for cooling material during continuous vacuum forming. The apparatus includes one or more cooling regions positioned adjacent one or more vacuum regions. A rotatable support belt including perforations therein supports a flexible patterned belt. The flexible patterned belt includes apertures spaced along the length and width thereof. The one or more cooling regions provide a cooling fluid to be drawn through the apertures in the flexible patterned belt to form an area of cooling fluid on the flexible patterned belt which contacts a bottom surface of a hot material received on the flexible patterned belt in order to cool the bottom surface of the material and the flexible patterned belt. The vacuum regions are in fluid flow communication with the perforations of the support belt and the apertures of the flexible patterned belt for drawing the material onto the flexible patterned belt.

Abstract: A low crystallizability polypropylene sheet which has an average spherulite radius between 0.1 ?m and 4 ?m, an average number of spherulites of 600/mm2 or less in a sheet cross section, a solid density of 0.895 g/cm3 or less, a fusion enthalpy H of less than 90 J/g at the highest endothermic peak of the differential scanning calorimetry (DSC) curve, a degree of gloss of 90% or higher on at least one side and shows an exothermic peak of 1 J/g or higher at the low temperature side of said highest endothermic peak and a thickness of 50 ?m or more.

Abstract: The invention relates to a method for producing extruded, cellulosic continuous shaped bodies from an extrusion solution containing cellulose, water and tertiary amino-oxide. In order to improve the textile properties of the extruded continuous shaped bodies with regard to the prior art, the invention provides that the continuous shaped body (5) is conveyed, with essentially no tensile stress, on a conveying device (11) between an extrusion nozzle opening and a take-off unit (24). To this end, the speed of conveyance of the interconnected conveying device (11) is preferably less than the extrusion rate and less than the take-off rate of the take-off unit (24). By employing these measures, the textile properties such as loop strength and tendency to fibrillate can be considerably improved.

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: A topsheet for body fluids absorbent article is made of thermoplastic synthetic fibers mechanically entangled so as to extend substantially in a desired one direction and formed with liquid-permeable openings. The openings comprise a first group of openings each having a substantially oval shape defined by its major axis extending substantially in parallel to the direction in which the fibers extend and its minor axis extending orthogonally to the major axis and a second group of openings each having a substantially oval shape defined by its minor axis extending substantially in parallel to the direction in which the fibers 11 extend and its major axis extending orthogonally to the minor axis.

Abstract: This invention relates to methods and apparatus for manufacturing shaped polymeric articles by substantially continuous vacuum forming. The method includes providing a sheet of hot polymeric material which is disposed onto a rotating belt having a mold impression. Vacuum pressure is applied to the polymeric material through the belt so as to draw the hot polymeric material into intimate contact with the mold impression to form a patterned sheet portion and a remaining sheet portion. This method thereafter cools at least the patterned sheet portion below a heat deflection temperature of the polymeric material, forms the remaining sheet portion, and then cools the remaining sheet portion below the heat deflection temperature so that features other than the central pattern, such as nail and butt edges, can be mechanically worked into the polymeric sheet.

Abstract: A nonwoven fabric from spun fibers wherein the density of the spun fibers in the fabric varies between strips of relatively high density and strips of relatively low density. The strips extend along the length of the fabric in the machine direction in an alternating pattern, with the high density strips separated from each other by low density strips. The alternating high density and low density strips provide the fabric with a higher percent elongation in the cross direction than in the machine direction. The alternating pattern is achieved through use of a pattern screen defining a plurality of elongated air permeable regions separated by elongated substantially or relatively air impermeable regions, the elongated regions extending in the machine direction in an alternating pattern, with the air permeable regions separated from each other by the substantially or relatively air impermeable regions.

Abstract: A nonwoven fabric from spun fibers wherein the density of the spun fibers in the fabric varies between strips of relatively high density and strips of relatively low density. The strips extend along the length of the fabric in the machine direction in an alternating pattern, with the high density strips separated from each other by low density strips. The alternating high density and low density strips provide the fabric with a higher percent elongation in the cross direction than in the machine direction. The alternating pattern is achieved through use of a pattern screen defining a plurality of elongated air permeable regions separated by elongated substantially or relatively air impermeable regions, the elongated regions extending in the machine direction in an alternating pattern, with the air permeable regions separated from each other by the substantially or relatively air impermeable regions.

Abstract: This invention relates to methods and apparatus for manufacturing shaped polymeric articles by substantially continuous vacuum forming. The method includes providing a sheet of hot polymeric material which is disposed onto a rotating belt having a mold impression. Vacuum pressure is applied to the polymeric material through the belt so as to draw the hot polymeric material into intimate contact with the mold impression to form a patterned sheet portion and a remaining sheet portion. This method thereafter cools at least the patterned sheet portion below a heat deflection temperature of the polymeric material, forms the remaining sheet portion, and then cools the remaining sheet portion below the heat deflection temperature so that features other than the central pattern, such as nail and butt edges, can be mechanically worked into the polymeric sheet.

Abstract: A porous structure is provided between a forming member and an underlying support structure so as to facilitate the drainage of liquid through the porous member when a web is supported on the porous member and columnar streams of liquid are directed at the web to form apertures in the web. The porous structure can include a plurality of spaced-apart, wire-like elements, a metal screen, thermoplastic netting, mesh, webbing, and the like. An improved apertured web made with the improved process employing such a porous structure has little or no lining or marking and has relatively few, if any, poorly formed apertures.

Abstract: A lamination process for orienting and conforming a film or sheet material to a substrate surface having a surface feature such that the film or sheet material reflects the surface feature includes interposing an adhesive between the film or sheet material and the substrate surface and opposing the film or sheet material and the substrate surface; providing at least two manifolds, where each manifold provides a plurality of flow streams of a pressurized liquid, each flow stream being oriented to effectuate a clear but minimally overlapped resulting flow stream from each manifold; and directing the resulting flow streams onto the film or sheet material to coincide at a contact nip line with at a force effective to conform the film or sheet material to the surface feature of the substrate surface. The resulting flow streams are maintained for sufficient time to adhere the film or sheet material to the substrate.

Abstract: According to the invention thin sheets of foil are stiffened in a particular way by means of vault-structuring. The vault-structuring occurs either by self-organizing or following a self-organized design with a spade-shaped or drop-shaped pattern.

Abstract: A process of making a biaxially-oriented multilayer film, comprises extruding a tubular multilayer tape and inflating the tape so that the tape is biaxially oriented by stretching in the transverse direction and machine direction at the same time, so that a tubular multilayer film is formed.

Abstract: A fiber-reinforced, tubular food casing based on regenerated cellulose, which is produced using an amount of viscose solution which is decreased by 10 to 30% in comparison with the standard casing at a spinning speed increased by at least 25%.

Abstract: A porous structure is provided between a forming member and an underlying support structure so as to facilitate the drainage of liquid through the porous member when a web is supported on the porous member and columnar streams of liquid are directed at the web to form apertures in the web. The porous structure can include a plurality of spaced-apart, wire-like elements, a metal screen, thermoplastic netting, mesh, webbing, and the like. An improved apertured web made with the improved process employing such a porous structure has little or no lining or marking and has relatively few, if any, poorly formed apertures.

Abstract: A process for producing a non-woven fabric of ultrafine polyolefin fibers by subjecting a web of splittable conjugate polyolefin fibers to a water needle processing, and non-woven fabric thus obtained are described. The polyolefin composite fibers, contain 1.0 to 7.0% by weight of a hydrophilic component blended therein. The non-woven fabrics include ultrafine fibers having a size of 0.5 denier or less and a non-circular cross-section. Splitting and peeling off of the conjugate fibers and generation of static electricity with the composite fibers at a carding step is suppressed. The non-woven fabrics have an excellent wiping property, softness, and hydrophilic property.

Abstract: Oil resistant adhesive compositions and nonwoven articles comprising an adhesive prepared from polymeric dimer fatty acid polyamide resins which are especially suited for use in the elastic attachment of disposable nonwoven products and particularly for leg or waist bond closures for disposable products such as diapers are disclosed.

Abstract: A para-oriented polyamide porous film comprising a fibril having a diameter of not more than 1.mu., with fibrils planarly arranged as a network or nonwoven fabric and laminated in a layer, the thermal linear expansion coefficient at 200.degree.-300.degree. C. within .+-.50.times.10.sup.-6 /.degree.C. and 30-95% vacant spaces. Also, a battery separator using the porous film. Also, a production process of: (a) forming a film-like material from a solution containing 1-10% of a para-oriented aromatic polyamide having an inherent viscosity of 1.0-2.8 dl/g and 1-10% of a chloride of an alkali metal or an alkali earth metal in a polar amide or polar urea solvent; (b) maintaining the film-like material at not less than 20.degree. C. and not more than -5.degree. C.

Abstract: Convoluted tubing of thermoplastic resin is made by extruding the resin as a molten tubular extrudate, feeding said extrudate into the interior of a rotating tubular member which has a helical thread in the interior of said member, the spiral thread having a deformation zone receiving the extrudate and a cooling zone downstream from the deformation zone. A vacuum can be used to force the extrudate against the spiral thread in the deformation zone to spirally convolute the extrudate. The rotation of the tubular member causes the resultant convoluted tubing to engage the spiral thread in the cooling zone for conveyance through such zone. Apparatus comprising the rotating tubular member with the interior thread for forming the convoluted tubing is provided.

Abstract: The present invention relates to a method for the production of a fiber-reinforced cellulose tube by continuous coating of a fibrous non-woven fabric with an alkaline viscose solution which is neutralized by means of an acid-containing precipitating liquid and is converted into regenerated cellulose, wherein on the path between viscose coating and immersion in the precipitating bath, aqueous, acid-containing precipitating agents are caused to act upon the fresh viscose tube within the tube for the purpose of stiffening and regeneration to form regenerated cellulose, the process being begun with the application of the precipitating liquid directly after conclusion of the embedding of fiber in viscose and the precipitating liquid being guided together with the tube with the aid of optionally fixed internal devices which are designed in such a way that they support the tube that has had precipitating bath applied to it and in the process maintain it in rounded shape, that the length of the inner preliminary prec

Abstract: A coextruded, multilayer polymeric film having a core layer including a surfactant and at least one outer layer is placed on a forming structure. The forming structure moves in a direction parallel to the direction of travel of the multilayer film and carries the multilayer film in that direction. A fluid pressure differential is applied across the thickness of the multilayer film along the direction of movement of the forming structure. The fluid pressure differential is sufficiently great to cause the multilayer film to conform with the forming structure forming a formed polymeric web. The formed polymeric web is exposed to a temperature which is sufficiently great enough to allow the surfactant in the core layer to migrate to the outer layer to form a surfactant treated formed polymeric web.

Abstract: Apparatus and process for gauging and controlling extruded profiled elements, particularly extruded profiled elements made of synthetic material. The apparatus includes at least one control and correction gauge arrangeable downstream of an extrusion die along the extrusion direction and in which there is a passage shaped so as to match the profile of the extruded profiled element. The passage can be crossed by the extruded profiled element, and there are holes and/or channels for heating and cooling preset regions of the profiled element to correct the profile and/or the internal tensions of the profiled element.

Abstract: The invention relates to a method in connection with a process for insulating or sheathing conductors or the like, wherein plastic material is extruded into at least one layer on the surface of the conductor (1), and the conductor coated with the plastic material (2, 3, 4) is cooled in a predetermined manner. To avoid problems caused by the shrinking of the plastic material, after the cooling of the conductor (1) and the plastic material in vicinity to it to a predetermined level in the insulating or sheathing process, the surface layer of the plastic material and the plastic material portions in vicinity to it are reheated to a predetermined temperature in a pressurized space filled with a medium.

Abstract: A continuous, multi-phase process for microaperturing and microembossing a substantially continuous web of substantially planar polymeric film to conform with the image of multiple forming structures, each having a patterned forming surface with a multiplicity of fine-scale apertures and an opposed surface. Each forming structure is open from the apertures in the forming surface to its opposed surface. The web of film has an indefinite length, a first surface, a second surface and a thickness. The thickness is the distance between the first surface and the second surface. The process includes at least two sequential forming phases, one of which involves aperturing of the web of film to coincide with fine-scale apertures in the first forming structure and another of which involves conformance of the web of film to the profile of the fine-scale apertures in the second forming structure.

Abstract: A pressure-sensitive adhesive fastener having a textured fastening surface so as to have a relatively high shear resistance and a desired peel resistance. The pressure-sensitive adhesive fastener comprises a backing web having bulbous surface aberrations projecting from a first surface of the backing web and a layer of pressure-sensitive adhesive coated over and bonded to at least a portion of the surface of the bulbous surface aberrations of the backing web. The present invention also relates to a fastening system using the pressure-sensitive adhesive fastener of the present invention.

Abstract: A low fluid pressure dual-sided fiber entangling method and apparatus for manufacturing a nonwoven fabric. A fibrous starting material whose individual fibers are capable of movement relatively to one another under the influence of applied fluid forces is subjected to coacting opposed fluid streams while being confined between a flexible screen belt and a rigid perforated hollow drum. The fibers of the starting material are entagled under the effect of fluid forces applied in opposition, forming a reticular network which defines a pattern of blind holes, each hole extending transversely to the fabric plane and containing a protuberant fiber packing at a closed end thereof.

Abstract: A process of expanding plastics film is disclosed, together with an apparatus for performing that process, in which expansion of the plastics film is performed under the control of a liquid providing a stable hydraulic mass, by the downward extrusion and drawing of the plastics film, and the final expansion thereof, exclusively under the influence of the static and dynamic pressure of a hydraulic mass, at a position spaced downwardly of the extrusion head, the hydraulic mass being one that remains in a liquid phase at all temperatures encountered during the step of lateral stretching of the plastics film, to the exclusion of vaporization of the hydraulic mass.

Abstract: A soft, silky, cloth-like polymeric web exhibiting either patterns of microapertured or microbubbled surface aberrations, said webs further including a contrasting visually discernible pattern which imparts an embossed appearance to at least one surface thereof. Such polymeric webs may be either fluid-pervious or fluid-impervious, as desired, depending upon the particular end use. In a particularly preferred embodiment, the visually discernible pattern comprises a regularly repeating pattern which imparts an improved aesthetic appearance to the webs. Method and apparatus for producing such polymeric webs are also disclosed.

Abstract: A method for making hollow fibers having a selective permeability, wherein a majority of the hollow fibers each has on the periphery thereof 1 to 10 fins extending in the longitudinal direction, and the occupancy ratio y of the sections, defined by the peripheries, of all the hollow fibers exclusive of the fin portions in the hollow fiber bundle to the section, vertical to the axial direction of the hollow fiber bundle, of the inner wall of the shell is within a range defined by the following formula (I):41-3.1.sqroot..alpha.x.ltoreq.y.ltoreq.61-3.1.sqroot..alpha.x (I)wherein x stands for the average fin number per hollow fiber in the hollow fiber bundle, and .alpha. indicates the ratio H/d of the average fin height H (.mu.)in the hollow fiber bundle to the average outer diameter d (.mu.) of the hollow fibers exclusive of the fin portions.

Abstract: A process of cooling a heated polyethylene terephthalate film by applying cooling liquid to both surfaces of the heated film and, after the temperature of the film has decreased sufficiently, removing the cooling liquid from the film, wherein the cooling liquid has a pH value between 6 and 3.

Abstract: Processes for extruding thermoplastic coatings on substrates are provided by this invention. The processes include directing a substrate between two pressure roll means wherein one of the pressure roll means has a temperature less than the melting point of the thermoplastic. Next, the processes include providing a molten curtain of thermoplastic which is then directed with a current of a fluid medium, such as compressed air, so as to cause at least a first portion of the molten curtain to contact the first pressure roll means for a time sufficient to form a thermoplastic sheet. Next, the processes include extruding at least this thermoplastic sheet with the substrate between the two pressure roll means so as to form an extruded substrate having a thermoplastic layer which is separable from the substrate.

Abstract: Isotropic microporous polysulfone membranes can be prepared by using a particular combination of casting solution and precipitation solution formulations, and casting conditions. Both hollow fiber and flat membranes can be prepared in this manner. The membranes are skinless and are characterized by uniform porosity throughout the membrane.