Abstract: Process for the preparation of polyether-amide solutions, steam-sterilizable dialysis membranes obtainable using the polyether-amide solutions, and a process for the production of these membranes.Polycondensation of one or more dicarboxylic acid derivatives of the formula I ##STR1## with one or more aromatic diamines of the formula II ##STR2## and, if appropriate, m-phenylenediamine, in aprotic polar solvents is known.As a result of passing ammonia, in an amount sufficient to neutralize the HCl formed, into the polymer solution obtained after the end of the polycondensation and filtering off the ammonium chloride formed, it is possible to prepare neutral, salt-free and particularly storage-stable polyether-amide solutions which can be further processed to membranes without isolation of the polymer. The resulting membranes are steam-sterilizable, chemically and thermally stable and show efficiency data in the region of that of good high-flux dialysis membranes.

Abstract: Highly uniform microporous foam suitable for medical applications and methods for preparing these foams. The highly uniform microporous foams are of controlled pore size that may be utilized in a variety of applications. In preparing the foams, an organic crystalline polymer is melted and combined with a selected solid crystalline fugitive compound to produce a substantially isotropic solution. The solution is cooled under controlled conditions, which foster solid--solid phase separation by the simultaneous crystallization of the fugitive compound and the polymer, to produce a foam precursor containing the solidified fugitive compound dispersed through a matrix of the organic polymer. Crystals of fugitive compound are then removed by solvent extraction and/or sublimation, or like process to produce microcellular foams having a continuous, open-cell structure.

Abstract: An implant is provided with an open-celled silicone elastomer foam outer layer. The implant may be formed by compressively deforming beads mixed with liquid elastomer in a mold containing a preformed support structure. The elastomer is cured and the beads dissolved out. Infusion and sensor catheters covered with the foam provide improved transport rates and faster response.

Abstract: The present invention provides a filtration medium comprising an ultrafiltration membrane and a monomer surface coating thereon of an acrylic or methacrylic acid monomer having alcohol functional groups, wherein the filtration medium after having been fully dried is characterized by having a titer reduction of at least about 10.sup.3 with respect to PP7 bacteriophage and a critical wetting surface tension of at least about 70 mN/m. The filtration medium preferably further comprises a fibrous nonwoven web embedded in the membrane. The present invention also provides a method of filtering a fluid through the present inventive filtration medium, as well as a method of preparing such a filtration medium.

Abstract: Plasticizer extraction from polymer membranes such as battery separators and the like, by exposure to a solvent-water combination. The water or steam is supplied to form an additional interface in a bulk solvent, and to agitate the solvent and control the temperature, as well. At the extractor exit, as well as the inlet, a water elbow is furnished in such a manner as to prevent solvent vapor contact with the atmosphere, and to keep the extractor body under some excessive pressure.

Abstract: A microporous membrane made of a non-crystalline polymer having, within its wall, microfibrils and slit-like micropores which are oriented in the lengthwise direction of the membrane, said slit-like micropores communicating from one surface to the other surface of the membrane, and forming a stacked construction. This membrane has a high flux value of AFR and WFR, excellent heat-, solvent-, and pressure-resistance, and a high mechanical strength, and does not contain any undesirable materials which eluate during use. This membrane is thus useful as a multi-purpose separation membrane, such as for medical uses, food industries, purification of water or air, and the separation of hot liquids.

Abstract: A process for the preparation of solid aggregate materials is disclosed. This process makes use of an aluminosilicate containing non-soft or waste material in combination with iron oxide, an alkali, a water soluble silicate and water to produce a mixture which is subsequently formed into a cohesive mass and then allowed to cure until the solid aggregate material is formed. The process is useful for both the production of low compressive strength materials such as landfill and high compressive strength materials such as bricks. As curable aluminosilicate containing materials includes fly ash, the process provides a means by which substantial amounts of such materials may be converted into a useful form.

Abstract: Polyamide (nylon) microporous membranes are prepared from a polyamide (nylon) polymer which contains aromatic rings, aliphatic carbon chains, and amide groups. The membranes exhibit improved long term performance characteristics.

Abstract: An improved, rapid process is provided for making microporous and mesoporous materials, including aerogels and pre-ceramics. A gel or gel precursor is confined in a sealed vessel to prevent structural expansion of the gel during the heating process. This confinement allows the gelation and drying processes to be greatly accelerated, and significantly reduces the time required to produce a dried aerogel compared to conventional methods. Drying may be performed either by subcritical drying with a pressurized fluid to expel the liquid from the gel pores or by supercritical drying. The rates of heating and decompression are significantly higher than for conventional methods.

Abstract: An asymmetric, microporous hollow fiber membrane comprising a polyimide is disclosed. The hollow fiber membrane is chemically inert to aqueous solutions and/or blood, is immediately rewettable after repeated steam and chemical sterilizations, has superior clearance, sieving, and water permeability characteristics and is usable over a wide range of applications such as dialysis and water filtration. Also disclosed is the process for manufacturing the polyimide hollow fiber membrane.

Abstract: A polymeric foam with continuous, open-cell pores containing living cells suitable for medical applications and methods for preparing these foams. The microporous foams are of controlled pore size that may be utilized in a variety of applications. In general, the foams are characterized in that the pores are continuous and open-celled. In preparing the foams, an organic polymer is melted and combined with a selected solid crystalline fugitive compound, that melts above about 25.degree. C. and/or that sublimates at above about 25.degree. C. or can be extracted, to produce a substantially isotropic solution. The solution is cooled under controlled conditions to produce a foam precursor containing the solidified fugitive composition dispersed through a matrix of the organic polymer. Crystals of fugitive composition are then removed by solvent extraction and/or sublimation, or a like process to produce microcellular foams having a continuous, open-cell structure.

Abstract: A filter for the filtration of a liquid, characterized by comprising a number of pores based on a number of microballoons formed in a hardened activation energy-setting resin layer, said pores being communicated with each other another so that said liquid can pass through said resin layer.The filter can be desirably formed in a desired form at a desired position at a high precision. The filter is suitable for use as a filter, especially in an ink jet head.

Abstract: The present invention is embodied in a method of producing a ceramic foam. The steps for producing the ceramic foam include first mixing a liquid pre-ceramic resin with a liquid phenolic resin, second allowing the resultant mixture to chemically foam, third curing the mixture for a time and at a temperature sufficiently to convert the mixture to a polymeric foam, and then heating the resultant polymeric foam for a time and at a temperature sufficiently to completely break-down polymers of the polymeric foam and convert the polymeric foam to a ceramic foam.

Abstract: A method of fabricating a controlled and uniform cell size blotter roll for blotting liquid images consisting of toner particles and carrier liquid. The method includes the step of mixing a first grade of salt having first particles of a first uniform size with a polymer material so as to form a first mixture. The method next includes a step of extruding the first mixture to form an extruded sleeve having intimately compacted polymer material and salt particles, an outer surface, and an inner surface defining a hollow interior.

Abstract: A vascular prosthesis is formed from a luminate vessel by precipitating onto the vessel a sheet of polymer from a solution including an organic solvent and precipitable polymer, and forming an aperture in the sheet, the aperture communicating with the lumen of the vessel.

Abstract: Baked pencil leads in which a filler such as flaky graphite is oriented in a concentric tubular form in an outer peripheral portion of each lead and which has one or more layers spaced in a radial direction from the outer peripheral portion and comprising the filler oriented in the concentric tubular form between the central portion and the outer peripheral portion of each lead and in which the filler is at random or radially oriented in the other portions of each lead. The baked pencil leads can be obtained by the use of a plurality of concentric conical tubular straightening plates having the sectional area of a flow path continuously decreased toward a nozzle orifice, in extruding a kneaded material mainly comprising the filler and a binder. In the baked pencil leads, strength can be remarkably improved without lowering density, and thus these baked pencil leads are excellent in the balance between the strength and the density.

Abstract: Addition of minor amounts of polymeric ethers, having oxyalkylene tentacles dangling from a carbon backbone, to ultrafiltration membranes improves rate of flow of purified water.

Abstract: A method of making a granulocyte adsorbing carrier, which is provided on its surface with irregularities having a center line average height Ra of 0.2 to 10 .mu.m and a mean spacing Sm of unevenness being within a range of 5 to 200 .mu.m, and a granulocyte remover employing the granulocyte adsorbing carrier, is conducted by methanol extraction.

Abstract: A modified polyvinyl chloride (PVC) separation membrane and a method for its preparation. The membrane has improved water permeability, contamination resistance, and hydrophilic properties. The method comprises contacting a PVC membrane with a treating solution containing a compound having an amino functional group, preferably in the presence of an alkali alcoholate catalyst, and heat-treating the PVC membrane at elevated temperature. The membrane can be dipped in the treating bath at high temperature or dipped in solution at room temperature and heat-treated after removal from the treating bath.

Abstract: Membranes composed of sulphonated polyaryl ether sulphones are disclosed in which the repetitive polymer units have the formula ##STR1## in which the aryl radicals are substituted by SO.sub.3 X where X is hydrogen or an alkali metal and the polymer includes from about 0.3 to 0.6 SO.sub.3 X radicals per unit. Processes for producing these membranes are also disclosed.

Abstract: The present invention provides a method for fabricating an asymmetric fluoropolymer membrane comprised of a fluoropolymer material, the membrane having a first surface comprised of a dense layer of the fluoropolymer material, and an opposite second surface comprised of a porous layer of the fluoropolymer material, comprising the steps of:(a) dissolving a fluoropolymer material in a solvent to form a solution;(b) depositing the solution on a casting surface; and(c) removing the solvent from the solution, thereby precipitating the membrane therefrom.The present invention also provides asymmetric fluoropolymer membranes comprised of a fluoropolymer material, wherein the membrane has a first surface comprised of a dense layer of the fluoropolymer material, and an opposite second surface comprised of a porous layer of the fluoropolymer material, and provides compositions for making the same.

Abstract: A spongy material is produced by the steps of suspending a suitable quantity of finely divided particles of a thermoreversible gel in an aqueous solution of glucomannan-rich flour, adding an alkali to the suspension, allowing the suspension to gel, freezing the gelled suspension, thawing and leaching the same with hot water to leave a skeleton of a water-insoluble, thermally irreversible gel matrix. After drying, a spongy material having a relatively uniform cellular texture and a pleasant feel to the skin is obtained.

Abstract: An acrylic synthetic fiber having in the transverse section thereof many openings having an indeterminate shape and a size of 0.1 to 1.6 .mu.m, wherein in the interior of the fiber, each opening forms a vein-like or straw-like void extending substantially in parallel to the longitudinal axis of the fiber and having a length of at least 60 .mu.m. This acrylic fiber is prepared by a) dissolving in a suitable solvent an acrylic polymer comprising at least 60 weight % of an acrylonitrile unit and 5 to 20 weight %, based on the weight of the acrylic polymer, of a polyalkylene glycol having a number average molecular weight of 5,000 to 50,000, b) aging the formed spinning solution for at least 4 hours, and c) extruding the spinning solution into a coagulating medium. The acrylic fiber is useful, e.g., as a frictional material comprising (a) a pulpy material made from the acrylic fiber, (b) a resin and (c) a filler.

Abstract: A process for thermoplastic processing and sintering an unplastifiable polymer comprises dispersing the unplastifiable polymer in powder form in a melt of a polyacetal or a mixture of polyacetals, cooling the resulting mixture, granulating it, forwarding the granules to a thermoplastic processing stage, injection or extrusion molding, exposing the molding to an atmosphere which contains an acidic gas, thereby de-polymerizing the polyacetal, enveloping the remaining porous molding on all sides in a gas/liquid-impermeable film, heating in an autoclave, and isostatically sintering the molding with pressure from all sides to form the finished article.

Abstract: A figure adjusting pad is capable of permitting a periphery of the pad to exhibit satisfactory shape retention without any independent core. The pad includes a silicone gel element formed therein with perforations and a stretchable fabric arranged for covering the silicone gel element and is trimmed. The perforations of the silicone gel element are formed by traces defined by elution of particles incorporated in a silicone gel stock solution for the silicone gel element. The trimmed portion includes the silicone gel element and is double-sewn together with the silicone gel element.

Abstract: Disclosed are a porous membrane which is made from a material containing, as its main component, a polytetrafluoroethylene resin, and a method of producing a porous membrane comprising forming a hollow or sheet-like film from a mixture of a polytetrafluoroethylene resin dispersion and a fiber-forming polymer, heat-treating the film at a temperature not lower than the melting temperature of the resin, and removing the fiber-forming polymer. Production of polytetrafluoroethylene porous membranes of a variety of pore sizes and porosities is possible by suitably varying the type and amount of additives added to an original liquid. The membrane finds spreading use in the field of separation in high-temperature and strong decomposing or strong dissolving mediums.

Abstract: A PVDF membrane exposed to a quarternary ammonium hydroxide solution retains it hydrophobicity and resistance to corrosive environments, yet spontaneously and completely wets with concentrated sulfuric and nitric acids. The modified membrane is incorporated into filtration devices that are in situ integrity testable in concentrated inorganic mineral acids.

Abstract: A method for preparing a microporous polyolefin shaped article which includes the steps of (1) melt blending a polyolefin with an additive which is miscible with the polymer at the melt temperature of the blend but which phase separates on cooling to form a solution; (2) forming a shaped article from the solution; (3) cooling the shaped article by use of a patterned chill roll to provide areas on the surface of the article where the polymer mixture does not contact the chill roll; and (4) (a) removing at least a substantial portion of the compatible liquid; or (b) stretching the article in at least one direction sufficient to permanently attenuate the article and effect orientation of the polymer; or (c) a combination of (a) and (b) to form a microporous polyolefin shaped article. The article is of substantially uniform thickness and has a patterned surface. The patterned surface provides substantially skinless areas having high microporosity and skinned areas or reduced porosity.

Abstract: A microporous polymeric film of high porosity comprises a halopolymer in which the repeating units are --(C.sub.n H.sub.2n)-- and --(C.sub.m X.sub.2m)-- in which each X independently represents fluorine or chlorine and the values of n and m are greater than one and less than six. The film is the result of firstly melt processing a mixture of the halopolymer, more than 150 parts by weight of an extractable salt and not more than 80 parts by weight of an extractable polymer per 100 parts by weight of the halopolymer, the extractable polymer not being completely and homogeneously mixed with the halopolymer and being less viscous than the halopolymer when both are molten so that the surfaces of the film resulting from melt processing are rich in the extractible polymer, and secondly extracting at least some of the extractable salt to render the film porous and extracting at least some of said polymer to impart surface porosity to the film.

Abstract: A novel process for making fluoropolymer-fiber composites is disclosed, which produces composites with improved physical properties. The composites are useful in parts that require chemical and/or thermal stability, as in chemical process equipment.

Abstract: A porous hydrophilic polypropylene membrane possessing a fine reticular structure, which is characterized by the fact that at least either of the opposite surfaces of membrane forms a surface layer of a reticular structure substantially equal to that in the interior of membrane, the membrane surfaces and the surfaces of pores in the membrane have a hydrophilic polymer chemically bonded thereto, and the membrane is composed substantially of a polypropylene possessing an average pore diameter in the range 0.1 to 2.0 .mu.m, a bubble point of not more than 2.0 kg/cm.sup.2, a porosity in the range of 60 to 85%, and a water permeability of not less than 2 ml/min.mmHgm.sup.2, a method for the production thereof, and a blood plasma separation apparatus incorporating such membranes in a housing are disclosed.

Abstract: A method of producing cellular, reticulated structures of elastomeric materials having interconnected networks of cavities which are useable in retaining and self-metering liquids. The method of producing such microporous polymeric structure includes forming a homogeneous mixture including at least one polymeric resin, combined with void former and a polyfunctional compound. The ratio by weight between the polymeric material and the polyfunctional compound is preferably from 18:1 to 1:3. The void former, polymeric material and polyfunctional compound are preferably admixed at approximately room temperature and then shaped at low temperature. The mixture is then cooled and the void former is extracted with a suitable solvent.

Abstract: Method of producing a paint or other plastic resinous material or product which on application to a surface imparts the surface with a tanned skin or leather-like appearance. The method includes incorporating into a paint or a plastic resin fluid a granular non-flocculating resin-plastic-compatible leather powder having a specific gravity of about 0.38 to about 0.5 g/cc. The leather powder is produced from tanned skin and/or leather chips and/or strips which have been steam heated a period of time sufficient to permit the chips and/or strips to swell and simultaneously cause the naturally occurring twisted and tangled collagen fibers therein to shrinkk and to automatically loosen and become less twisted and less tangled which upon pulverization produces a powder including relatively smooth granules having lubricity and relatively non-fibrous.

Abstract: A microporous polyolefin shaped article is provided. The article comprises a polyolefin substrate of substantially uniform thickness having a patterned surface, the patterned surface providing substantially skinless areas having high microporosity and skinned areas of reduced microporosity. A method for preparing the article is also provided.

Abstract: A method for the manufacture of a hollow fiber membrane by mixing polypropylene, an organic filler capable of uniformly dispersing in the polypropylene in a fused state and easily dissolving in an extractant being used, and a crystal seed forming agent. The resulting mixture, in a molten state, is discharged in the shape of a hollow fiber through an annular spinning nozzle and into contact with a liquid made of said organic filler or a compound similar thereto. This results in cooling and solidifying the hollow fiber, which is then forwarded into contact with an extractant incapable of dissolving polypropylene, to remove the organic filler and form the membrane.

Abstract: A method of producing a highly porous melt spun fibrous tube for use as a separation medium comprising melt spinning a blend containing from 30 to 70 parts by weight of a first polymeric component and from 70 to 30 parts by weight of a second polymeric component to form a tube having a wall consisting of interpenetrating networks of the two polymeric components and, using a suitable solvent, leaching out of the tube wall one of the two polymer networks so producing a tube having a wall comprising the other polymer network.

Abstract: A microporous polybenzimidazole membrane having a uniform pore structure and a narrow pore size distribution, and a process for making the membrane. The process requires coating a polybenzimidazole powder with a high temperature stable polymer and compression molding the coated particles at a temperature in the approximate range of 435.degree.-450.degree. C. to form a sheet or membrane. The polymer is then extracted from the sheet, leaving a fine, uniform, polybenzimidazole microporous structure.

Abstract: Asymmetric, semipermeable membranes cast from a solution comprised of poly(aryletherketone) dissolved in a strongly protic non-reactive acid.

Abstract: An electrode comprising a gas permeable and liquid permeable coating bonded to an ion exchange membrane, said coating comprising low overvoltage electrocatalytic particles, more electroconductive electrolyte resistant particles and an electrolyte resistant binder compatible with the membrane to bond the particles thereto, the electrode coating being provided with a plurality of pores with a pore size of at least 0.1 microns.Effective porosity is imparted to the layer of particles by means of a sacrificial, pore-forming agent and by leaching out such agent after the particles have been bonded together and the layer formed is in its desired thickness, preferably after it has been deposited upon the membrane.Surface resistivity of the layer is reduced and the layer is effectively reinforced by incorporating electroconductive particles which often have a higher overvoltage than the electrocatalytic particles and also have high electroconductivity.

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: This invention relates to methods for porous resin moldings, for ultrafine fibers for ultrafine fiber nonwoven fabrics. In essence, the invention comprises providing a molding, spun fiber or crude nonwoven fabric containing a thermoplastic resin and a special high molecular compound which has an adequate affinity for the thermoplastic resin and able to dissolve rapidly in water and dissolving out the high molecular compound from the molding, spun fiber or crude nonwoven fabric. The method of the invention involve no risk of explosion or fire hazard in manufacture, free from adverse effects on health, and help curtail the manufacturing time.

Abstract: There is disclosed a porous inorganic material, suitable for use as a support material for biological macromolecules, comprising substantially spherical particles of an aluminosilicate ceramic material, any internal cavities present in a particle occupying no more than 10% of the volume of the particle, each particle having a diameter in the range of from 5 micrometers to 5 millimeters and consisting predominantly of an open three-dimensional matrix of needles of the ceramic material each of which needles has a length in the range of from 2 to 20 micrometers and a width in the range of from about 0.2 to 2 micrometers, the ceramic needles defining between them interconnecting pores of width of from 0.1 to 5 micrometers. Also disclosed is a method of preparing such a porous inorganic material.

Abstract: A process for producing a polyhalogenated microporous film having a very narrow pore size distribution and good temperature and chemical resistance. The process involves blending a polyhalogenated copolymer with a polyethyloxazoline utilizing a solvent which is a nonsolvent for the polyhalogenated copolymer but a solvent for polyethyloxazoline, forming a film from the blend, drying the film, heating the film to a temperature at or above the melting point of the polyhalogenated copolymer and under conditions such that the microparticulate particles at their points of mutual contact will neck together to form a relatively continuous matrix and extracting the polyethyloxazoline from the film utilizing a solvent for the binder particle to form a microporous film.

Abstract: A method of making a plugged microporous film from a film which comprises a structural component having pores extending therethrough, and a plugging material within the pores, the method comprising:(a) selectively treating the plugging material so that its susceptibility to a crosslinking treatment differs from a first region of the film to a second region thereof;(b) crosslinking the plugging material at the second region of the film; and(c) removing the uncrosslinked plugging material from the first region of the film leaving plugs of crosslinked plugging material in the pores at the second region of the film.

Abstract: A process for producing a polyhalogenated microporous film having a very narrow pore size distribution and good temperature and chemical resistance. The process involves blending a polyhalogenated copolymer having a very small particle size with a binder polymer utilizing a solvent which is a nonsolvent for the polyhalogenated copolymer but a solvent for the binder polymer, forming a film from the blend, drying the film, heating the film to a temperature at or above the melting point of the polyhalogenated copolymer and under conditions such that the microparticulate particles at their points of mutual contact will neck together to form a relatively continuous matrix and extracting the binder polymer from the film utilizing a solvent for the binder particle to form a microporous film.

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.

Abstract: The present invention is directed to a membrane filter having predetermined controlled porosity and to the method for making such a membrane filter. The membrane filter has a plurality of pores, with each of the pores having a predetermined size from top to bottom located at predetermined locations across the membrane filter. The pores each have a tapered configuration with the larger opening at the surface of the membrane filter and the smaller opening at the bottom of the membrane filter. This tapered configuration permits pre-filtering. The membrane filter is made by a method which utilizes a probe having a tapered piercing tip that pierces the membrane to form the pores. Preferably, a plurality of probes are nested together so that a predetermined number of pores can be made with one reciprocation. If additional pores are needed for increased flow rate, the bundled probes can be laterally shifted or jogged with respect to the membrane material and further pores formed.

Abstract: A process for preparing microporous membranes by coextruding a melt of a plurality of interdigitated layers of at least two polymers, one having preferential solubility over the other, dividing and reorienting the layers of said melt into discrete domains of random orientation, forming a thin membrane or like article and leaching the preferentially soluble polymer out of the resulting article.

Abstract: A method for producing a biodegradable polymer having a preferentially oriented pore structure and a method for using the polymer to regenerate damaged nerve tissue is disclosed. The preferentially oriented pores are produced by an axial freezing process and serve to promote proper vascularation and regeneration of the damaged nerve. Preferably, the biodegradable polymer comprises uncrosslinked collagen-glycosaminoglycan.

Abstract: A fishing line, or just a leader, has a core (11) which is coated by plastic material as it is pulled through an extruder (3) and then a quench bath (4) by a variable speed drive device (9). Very fine control can be exerted by laser devices (11, 12) before and after coating, and adjusting a selection of parameters such as drive speed, extrusion rate, pressure and temperature, and cooling. A double coating may be applied or additives mixed in the extruded plastics which will give a desired floating or sinking characteristic.