Abstract: Process for producing an integrally asymmetrical hydrophobic polyolefinic membrane with a sponge-like, open-pored, microporous support structure and a separation layer with a denser structure compared to the support structure, via a thermally induced liquid-liquid phase separation process. A solution of at least one polyolefin in a solvent system consisting of a compound A and a compound B is extruded to form a shaped object. Compound A is a weak solvent and compound B a non-solvent for the polymer. After leaving the die, the shaped object is cooled using a solid or liquid cooling medium that does not dissolve or react chemically with the polymer at temperatures up to the die temperature, until the phase separation and solidification of the high-polymer-content phase take place.

Abstract: The present invention provides imprint compositions useful for capturing, isolating, detecting and/or quantifying macromolecules in a sample, methods of making and using the same. Generally, the imprint compositions comprise a matrix material defining an imprint of a template molecule, and the template molecule typically corresponds to a portion of a macromolecule of interest.

Abstract: To provide a cellulose acetate semipermeable membrane having a high filtration rate and high mechanical strength and which is hardly degraded by microorganisms, the present invention provides a cellulose acetate semipermeable membrane containing a cellulose acetate having an &agr;-cellulose content of not less than 99% by weight, a 6 wt/vol % viscosity of 20 to 220 mPa·s at 25±1° C. and an acetylation degree of 58 to 62%. The cellulose acetate semipermeable membrane is suitable particularly as a hollow fiber membrane.

Abstract: Solid free form fabrication techniques such as fused deposition modeling and three-dimensional printing are used to create a dental restoration. Three-dimensional printing comprises inkjet printing a binder into selected areas of sequentially deposited layers of powder. Each layer is created by spreading a thin layer of powder over the surface of a powder bed. Instructions for each layer may be derived directly from a CAD representation of the restoration. The area to be printed is obtained by computing the area of intersection between the desired plane and the CAD representation of the object. All the layers required for an aesthetically sound restoration can be deposited concurrently slice after slice and sintered/cured simultaneously. The amount of green body oversize is equivalent to the amount of shrinkage which occurs during sintering or curing.

Abstract: A polysaccharide sponge characterized by having: (i) an average pore size in the range between about 10 &mgr;m to about 300 &mgr;m; (ii) an average distance between the pores being the wall thickness of the pores in the range between about 5 &mgr;m to about 270 &mgr;m; and (iii) an E-modulus of elasticity being a measure of the rigidity of the sponge in the range of about 50 kPa to about 500 kPa.

Abstract: A polyacrylonitrile-based hollow fiber filtration membrane, wherein said membrane comprises a sponge structure free from polymer defect sites of sizes larger than 10 &mgr;m inside the membrane, pore sizes of the membrane continuously decrease towards both surfaces of the membrane, and the pore size on the outer surface of the membrane is differentiated from that on the inner surface.

Abstract: Solid free form fabrication techniques such as fused deposition modeling and three-dimensional printing are used to create a dental restoration. Three-dimensional printing includes ink-jet printing a binder into selected areas of sequentially deposited layers of powder. Each layer is created by spreading a thin layer of powder over the surface of a powder bed. Instructions for each layer may be derived directly from a CAD representation of the restoration. The area to be printed is obtained by computing the area of intersection between the desired plane and the CAD representation of the object. All the layers required for an aesthetically sound restoration can be deposited concurrently slice after slice and sintered/cured simultaneously. The amount of green body oversize is equivalent to the amount of shrinkage which occurs during sintering or curing.

Abstract: A porous material is disclosed, made of a semi IPN type polymer alloy of a crosslinked polymer (A) obtained by the crosslinking polymerization of a crosslinking-polymerizable vinyl monomer and/or oligomer (a) with a non-crosslinked polymer (D) which is soluble in a solvent (B) capable of dissolving said monomer and/or oligomer (a) therein and subjecting said crosslinked polymer (A) to gelation but is insoluble in a coagulating solution (C) which is compatible with said solvent (B) but doesn't subject said crosslinked polymer (D) to gelation. A porous material excellent in mechanical strength as well as in heat resistance can be prepared. Various functional groups can be introduced into the surface of the porous material. Further, the pore diameter can be easily controlled.

Abstract: A porous hollow fiber polyvinylidene fluoride resin membrane, characterized in that the membrane has a unitary three-dimensional network structure entirely composed of a polyvinylidene fluoride resin and has an inside diameter of 1.5-5 mm and a wall thickness of 0.5-2 mm and in that the relationship between membrane bubble point and water flux per unit wall thickness is on or above the curve shown in FIG. 1.

Abstract: Process for preparing a flexible polyurethane foam by reacting a polyisocyanate and two different polyols under foam forming conditions so as to prepare a rigid foam and by crushing the rigid foam so obtained in a direction perpendicular to the direction of rise of the foam. Flexible foams are obtained which do not show a major glass transition temperature between −100° C. and +25° C. and which have an anisotropy of 1.80 to 4.00.

Abstract: An improved dielectric material having pores formed therein and a method for forming the material are disclosed. The material is formed of a polymer. Pores within the polymer are formed by forming solid organic particles within the polymer and eventually vaporizing the particles to form pores within the polymer.

Abstract: Systems and methods for processing dope for the manufacture of microporous phase inversion membrane having any one of a plurality of different pore sizes from a single master dope batch is disclosed. The systems and methods include formulating a single master batch of dope preferably maximizing the non-solvent to solvent ratio for a given weight percentage of polymer for use in a microporous phase inversion membrane casting operation to produce phase inversion membranes having one of a plurality of different predetermined pore sizes. The master dope batch is controllably formulated in a vessel such that the temperature of the dope does not exceed a predetermined maximum mixing temperature and is maintained at a relatively low temperature (lower than the mixing temperature) suitable for storage.

Abstract: A method for preparing microparticles having a selected polymer molecular weight. The hold time and temperature of a solution containing a nucleophilic compound and a polymer having a starting molecular weight are controlled in order to control the molecular weight of the polymer in the finished microparticle product. In this manner, a selected polymer molecular weight in the finished microparticle product can be achieved from a variety of starting material molecular weights.

Abstract: A mesoporous polymeric membrane for use as an ionically-conductive inter-electrode separator in a rechargeable battery cell is prepared from a coatable composition comprising a polymeric material, a volatile fluid solvent for the polymeric material, and a second fluid miscible with and of lesser volatility than the solvent, the second fluid being a nonsolvent exhibiting no significant solvency for the polymeric material. A layer is cast from the composition to form a layer which is gelled and solidified to a self-supporting membrane by volatilizing the solvent and nonsolvent coating vehicle fluids under conditions in which the solvent volatilizes at a rate substantially faster than that of the nonsolvent. As a result the polymeric material initially gells in the more nonsolvent-predominant regions of the layer and isolates the nonsolvent as droplets substantially uniformly distributed throughout a matrix of polymeric material.

Abstract: Lyocell fibres contain elongated domains of polyester, polyamide or an olefin copolymer, the domains having an aspect ratio at least 1.5 and being aligned substantially parallel to the axis of the fibre. A process for the preparation of lyocell fibre or film by extruding a solution of cellulose in amine oxide through a spinneret or film die at elevated temperature via an air gap into an aqueous precipitation bath is characterised in that 0.1 to 60 wt % based on cellulose of a thermoplastic low-melting polymer is incorporated into the cellulose solution. A process for the preparation of a bicomponent fibre by extruding two polymers through a spinneret in side-by-side relationship at elevated temperature is characterised in that one of the polymers is a solution of cellulose in amine oxide and the other polymer is a molten thermoplastic polymer having a melting point above 25° C. but below the extrusion temperature.

Abstract: The present invention relates to hydrophilic membranes containing blends of polysulfone polymers and sulfonated polymers or copolymers, where the sulfonated polymers or copolymers are sulfonated before blending with the polysulfone polymer. The invention also relates to methods of preparing the hydrophilic membranes. In one aspect of the invention, the membranes are formed by casting a mixed polymer solution comprising a sulfone polymer and a copolymer of a sulfonated polymer and a sulfone polymer and quenching the film in an aqueous bath to produce a coagulated membrane. The membranes can be ultrafiltration or microfiltration membranes, symmetric or asymmetric.

Abstract: A composite polyamide reverse osmosis membrane and method of producing same. In one embodiment, the membrane is made by coating a porous polysulfone support for about 40 seconds with an aqueous solution containing (i) a polyfunctional primary or secondary amine in the form of 1.6 wt. % of meta-phenylenediamine (MPD), (ii) a polyfunctional tertiary amine in the form of 0.4 wt. % N,N,N′,N′-tetramethyl-1,6-hexanediamine (TMHD), and (iii) a polar solvent in the form of 0.2 wt. % 2-ethyl-1,3-hexanediol (EHD). Next, the excess aqueous solution is removed, and the coated support is dipped for about 1 minute in a 0.1 wt. % organic solvent solution of trimesoyl chloride (TMC) in a mixture of alkanes having from 8 to 12 carbon atoms. After draining the organic solvent solution off, the resulting composite membrane is air dried at room temperature for about 1 minute and then rinsed in a 0.2% Na2CO3 aqueous solution for 30 minutes at room temperature. The resultant membrane exhibits a flux of 46.

Abstract: It is an object of the present invention to provide a microporous polyolefin membrane, high in elongation and porosity, low in shrinkage, and capable of improving battery characteristics, safety and productivity, when used for battery separators. The microporous polyolefin membrane of the present invention comprises (A) an ultra-high-molecular-weight polyolefin having a weight-average molecular weight of 5×105 or more, or (B) a composition containing an ultra-high-molecular-weight polyolefin having a weight-average molecular weight of 5×105 or more, and having a porosity of 45 to 95%, elongation at break of 300% or more, bubble point exceeding 980 KPa and thermal shrinkage in the TD direction of 3% or less. The present invention also provides a method for producing the above microporous polyolefin membrane.

Abstract: A device useful for localized delivery of a therapeutic material is provided. The device includes a structure including a porous material; and a water-insoluble salt of a therapeutic material dispersed in the porous material. The water-insoluble salt is formed by contacting an aqueous solution of a therapeutic salt with a heavy metal water-soluble salt dispersed throughout a substantial portion of the porous material. The porous material can be made of a polymer other than fibrin with fibrin incorporated into the pores, which can be the only layer of polymeric material on the medical device (e.g., stent). A new method for preparing a porous polymer material on a medical device.

Abstract: A fiber material of PTFE and, optionally, hydrophilizing additives, for use in the production of diaphragms for the electrolysis of alkali chlorides, as well as for filter layers. The fiber material comprises fiber bundles and these, in turn, comprise individual microfibrils, there being irregularly shaped interstices between the microfibrils. The fiber material is produced in that a PTFE dispersion, consisting of a salt solution with PTFE particles and, optionally, hydrophilizing additives, is treated in a hot gas/vapor stream in a fluidized bed apparatus charged with inert solids. The method permits the fiber material to be produced also in larger quantities in an economic manner.

Abstract: A process for producing a nanoporous polymer film of no greater than 10 micron thickness having low dielectric constant value, including the steps of: (a) providing a polymer in a solution with at least two solvents for the polymer in which a lowest boiling solvent and a highest boiling solvent have a difference in their respective boiling points of approximately 50° C. or greater; (b) forming a film of the polymer in solution with at least the two solvents on a substrate; (c) removing a predominant amount of the lowest boiling solvent; (d) contacting the film with a fluid which is a non-solvent for the polymer, but which is miscible with the at least two solvents to induce phase inversion in the film; (e) forming an average pore size in the film in the range of less than 30 nanometers. The present invention is also nanoporous films made by the above process.

Abstract: A method for producing polymeric, e.g., polybenzimidazole (PBI) films, is provided by forming a porous membrane by coagulating a polymeric dope solution in a liquid coagulation bath containing a non-solvent alone or a mixture of a non-solvent and solvent; submerging the resulting membrane into a non-solvent bath to remove any residual solvent; placing the membrane into an acid solution, whereby the pores become filled with the acid solution; and drying the membrane to remove residual non-solvent which collapses the porous structure entrapping the acid and forming a dense film. An alternative method involves coagulating said polymer solution directly into an acid/solvent/non-solvent mixture to produce a porous membrane which imbibes the acid solution, followed by drying.

Abstract: The present invention relates to anionically charge-modified membranes and methods of preparing such membranes. In one major aspect of the invention, the membranes are internally hydrophilic and formed from casting a film of a mixed polymer solution that includes an anionic agent.

Abstract: A porous membrane is provided which is formed from a porous polyperfluorocarbon membrane substrate having its surface modified with a perfluorocarbon polymer composition. The modified surface is directly wet with an aqueous liquid.

Abstract: Improved asymmetric hyperfiltration membranes and their method of preparation and use are disclosed. The membranes are fashioned from polyimides and conditioned with a lubricating oil. Permselective separation of aromatic hydrocarbons from non-aromatic hydrocarbons in a feed stream may be accomplished using the membranes under hyperfiltration conditions.

Abstract: The invention relates to a process for the manufacture of cellulosic flat films and of cellulosic membranes in the form of flat membranes whereby a solution of cellulose in an aqueous tertiary amine oxide is extruded by means of an extrusion nozzle, which has an extrusion gap, whereby the solution is shaped in the form of a film and the solution is led into a precipitation bath via an air gap and is characterized in that an extrusion nozzle is used which has an extrusion gap with a minimum length of 40 cm.

Abstract: The invention relates to the use of a neutral or cationic polymer for preventing activation of the contact phase of blood or plasma which comes into contact with a semi-permeable membrane based on polyacrylonitrile bearing fixed negative charges, which is fitted in apparatus for the treatment of blood or plasma by extra-corporal circulation, by combination of the neutral or cationic polymer, before or after formation of the membrane and before its sterilization, so as to modify the electrical properties of the membrane, the Zeta potential “Z” and the electrical resistivity “R” in order to obtain: either an electrokinetic index “I” of less than or equal to 0.8, “I” corresponding to Log10 (|Z|/R), or a positive Zeta potential “Z” of between 0 and 15 mV (limits not included).

Abstract: A hollow fiber filter membrane where the inner surface comprises a three-dimensional network structure having thick trunks of 10-30 .mu.m in maximum diameter and the average pore diameter of a minimum pore diameter layer of the membrane is 0.01 .mu.m or more and less than 1 .mu.m.

Abstract: Reverse osmosis membranes with improved water flux and excellent solute rejection characteristics are formed by interfacial reaction of an essentially monomeric polyamine reactant having an average of at least two amine functional groups with an essentially monomeric amine-reactive reactant having an average of at least 2.05 acyl halide functional groups, the polymerization reaction being conducted in the presence of a monohydric phenol on the surface of a porous substrate. A specific example is a high flux composite membrane prepared by coating a porous substrate with an aqueous solution containing about 0.1-20 wt % m-phenylenediamine and 0.1-9.9 wt % phenol, and interfacially contacting the coated substrate with a nonaqueous solution of about 0.01-10 wt % trimesoyl chloride for a time sufficient to form a polyamide coating, followed optionally by one or more washing and drying steps to remove the nonaqueous solvent and most or all of residual unreacted chemicals.

Abstract: A process for producing plexifilamentary products by spinning from a spin fluid of a polyolefin dissolved in a primary spin agent selected from the group consisting of 1,1,2-trichloro-2,2-difluoroethane and isomers thereof; 1,1,3-trichloro-2,2,3,3-tetrafluoropropane and isomers thereof; 1,2-dichloro-3,3,3-trifluoropropane and isomers thereof; and 1,2-dichloro-1-fluoroethylene; and a co-spin agent; and also a spin fluid of a polyolefin dissolved in a primary spin agent selected from the group consisting of 1,1,2-trichloro-2,2-difluoroethane and isomers thereof; 1,1,3-trichloro-2,2,3,3-tetrafluoropropene and isomers thereof; 1,2-dichloro-3,3,30-trifluoropropane and isomers thereof; and 1,2-dichloro-1-fluoroethylene; and a co-spin agent.

Abstract: Liposomal bupivacaine compositions are prepared using an ammonium sulfate gradient loading procedure, at a pH which prevents precipitation of the drug from the loading solution. Also described are liposome suspensions comprising `GMV` (giant multivesicular) liposomes and methods for their preparation. The liposomal compositions are characterized by high drug-to-lipid ratios and provide long term analgesia.

Abstract: In a method of making solvent and acid resistant membrane on the basis of polyacrylnitrile (PAN) and a comonomer copolymerized therewith wherein the membrane is formed from a solution by phase inversion, glycidylmethacrylate is used as the comonomer and the membrane formed thereby is then subjected to ammonia.

Abstract: A pharmaceutical implant for the delivery of an effective amount of a bioactive peptide or peptide analog over a period of 1 to 12 months. This implant has a diameter of about 1 to 2 mm, a length of between about 10 and 25 mm and is obtainable from a process which includes the steps of grinding a copolymer of lactic acid and glycolic acid having a ratio of glycolide to lactide units of from about 0 to 5:1 to a particle size of between about 50 and 150 .mu.m; sterilizing the ground copolymer with a dose of between about 1 and 2.5 Mrads of ionizing .gamma.-radiation; wetting the ground and sterilized copolymer with a sterile aqueous slurry of a bioactive peptide or peptide analog; aseptically blending the copolymer and the slurry to obtain a homogeneous mixture of the copolymer and between about 10 and 50% of the bioactive peptide or peptide analog; drying the mixture at reduced pressure and at temperature not exceeding 25.degree. C.

Abstract: A method for loading liposomes with biopolymeric substances functional in humans involves combining a physiologically compatible solution of the biopolymeric substances with one or more dry, liposome-forming lipids, effecting a lipid-containing fraction, combining the lipid-containing fraction with an organic solvent, effecting an organic solvent fraction, and drying the organic solvent fraction, which effects a dry fraction of liposomes loaded with the biopolymeric substances.

Abstract: As per the World Health organization (WHO) requirement, the water for drinking purposes should be 100% virus free. This invention reports a polymer impregnated porous substrate membrane and method for the preparation of said membrane for capturing viruses from water. The water filtered through the membrane prepared by the process of the present invention has been tested to be virus free and fully potable based on the tests carried out at the Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India and Sriram Institute for Industrial Research (an ISO 9001 R&D Organization), New Delhi, India. The invention will be of immense use especially for the developing countries and third world countries which are subjected to the problem of unsafe drinking water. This invention is useful also for the developed countries for use in water treatment plants due to highly industrialized nature and existence of a variety of manufacturing units like chemicals and fertilizers.

Abstract: This invention relates to a process for the preparation of an oral solid rapidly disintegrating dosage form of a pharmaceutically active substance which has an unacceptable taste which process comprises: (i) forming a solution or a suspension in a solvent of a water soluble or water dispersible carrier, a filler and the pharmaceutically active substance with the unacceptable taste in association with a lipid, the weight ratio of the pharmaceutically active substance to the lipid being in the range of from 1:1 to 1:10 and the weight ratio of the carrier to the lipid being in the range of from 5:1 to 1:15; (ii) forming discrete units of the suspension or solution; and (iii) removing the solvent from the discrete units under conditions whereby unit dosages are formed comprising a network of carrier/filler carrying a dosage of the pharmaceutically active substance in association with the lipid; oral solid rapidly disintegrating dosage forms prepared by such a process are also provided.

Abstract: Described are an injectable formulation of nanoparticulate naproxen that produces minimal or no pain or burning sensation upon administration, and methods of making and using such a formulation. The injectable formulation comprises nanoparticulate naproxen having a povidone polymer adsorbed on the surface thereof in an amount sufficient to maintain an effective average particle size of less than about 600 nm.

Abstract: A method for producing a highly permeable microporous polyolefin membrane including the steps of preparing a polyolefin solution containing 5-40 weight % of a polyolefin or a polyolefin composition and 95-60 weight % of a solvent, the polyolefin having a weight-average molecular weight of not less than 3.times.10.sup.5 and less than 1.times.10.sup.6 and a weight-average molecular weight/number-average molecular weight of 5-300, and the polyolefin composition having a weight-average molecular weight of not less than 3.times.10.sup.5 and less than 1.times.10.sup.6 and a weight-average molecular weight/number-average molecular weight of 5-300 as a whole, extruding the polyolefin solution, stretching the extrudate uniaxially at a draft ratio of 3-50 in a molten state, cooling the stretched extrudate to solidify to a gel-like sheet, removing residual solvent, drying the resultant sheet, and heat-setting at a temperature of 80.degree. C. or higher and its melting point or lower.

Abstract: A process for the entrapment of amphiphilic compounds as uncharged or ionic with different mole ratios of phospholipid to the amphiphilic compound. Preparations of ionic species of amphiphilic compounds in the absence of crystals can be prepared, while preparations of uncharged amphiphilic compounds can be prepared with the compound exclusively entrapped inside the liposomes, or partly entrapped inside the liposomes with extraliposomal crystals.

Abstract: Microcapsules containing a biologically active material which is sensitive to ultraviolet light are prepared which contain an ultraviolet light protectant selected from titanium dioxide, zinc oxide and mixtures thereof, suspended and thoroughly dispersed in a liquid.

Abstract: The present invention relates to the field synthetic polymeric membrane materials formed from casting polyvinylidene difluoride (PVDF) polymer solutions and/or dispersions. Membranes formed in accordance with the present invention are all highly porous. Both internally isotropic membranes and highly asymmetric PVDF membranes are disclosed. Membranes of the invention may be hydrophobic or hydrophilic. The membranes of the invention are useful in a variety of microfiltration and ultrathin applications.

Abstract: Compositions comprising an aqueous dispersion of lipid vesicles having an aqueous core, wherein the dispersion comprises at least one uncoated pigment dispersed in the aqueous phase and wherein the lipid vesicles with an aqueous core and a lipid membrane formed from at least one fatty acid ester, these compositions being stable, of homogeneous color and containing no or virtually no lumps of pigment, and a process for dispersing a filler in an oil-in-water dispersion of lipid vesicles by means of a high-pressure homogenizer.

Abstract: A process for preparing nanoparticles and microparticles is provided. The process involves forming a mixture of a polymer and a solvent, wherein the solvent is present in a continuous phase and introducing the mixture into an effective amount of a nonsolvent to cause the spontaneous formation of microparticles.

Abstract: Novel amidinium derivatives of formula (I), wherein R1 is a cholesterol derivative or an alkylamino-NR'R" grouping, and each of R2 and R3 is independently a hydrogen atom or a grouping of formula (II), wherein each of R4 and R5 is independently a hydrogen atom or a grouping of formula (III), are disclosed. The corresponding pharmaceutical compositions, which are particularly useful in gene therapy for transferring therapeutic genes into cells, are also disclosed.

Abstract: A microcapsule includes a shape memory resin shell wall formed with fissures that do not completely pass through the shell wall, and a dye encapsulated in the shell wall. The shell wall exhibits a temperature/pressure characteristic such that the fissures open, when the shell wall is squashed and compacted under a predetermined pressure at a predetermined temperature, whereby a seepage of the dye frog the squashed and compacted shell wall through the opened fissures is adjustable.

Abstract: A multivesicular liposome composition containing at least one acid other than a hydrohalic acid and at least one biologically active substance, the vesicles having defined size distribution, adjustable average size, internal chamber size and number, provides a controlled release rate of the biologically active substance from the composition. A process for making the composition features addition of a non-hydrohalic acid effective to sustain and control the rate of release of an encapsulated biologically active substance from the vesicles at therapeutic levels in vivo.

Abstract: High concentration drag reducing agents may be prepared by microencapsulating polymer drag reducing agent. The microencapsulation may be performed prior to, during, or after the polymerization of monomer into effective drag reducing polymer. If encapsulation is done before or during polymerization, a catalyst may be present, but little or no solvent is required. The result is very small scale bulk polymerization within the microcapsule. The inert capsule or shell may be removed before, during or after introduction of the microencapsulated drag reducer into a flowing liquid. No injection probes or other special equipment is expected to be required to introduce the drag reducing slurry into the liquid stream, nor is grinding (cryogenic otherwise) of the polymer necessary to form a suitable drag reducing agent.

Abstract: Methods for making microporous polyvinylidene fluoride (PVDF) membranes from vinylidene fluoride polymers and the products produced. The PVDF microporous membranes have a significantly faster flow rate at a given pore size as compared to equally-sized microporous membranes made by conventional procedures. The PVDF microporous membranes also have significantly smaller pore sizes than conventional microporous PVDF membranes. The present membranes have unique macrostructural features responsible, in part, for their unique functional properties. The process includes dissolving the polymer in a liquid that includes a solvent and a co-solvent for the polymer. The dissolution of the polymer can be at temperatures ranging from about 20.degree.C. to about 50.degree.C. while the formation of the microporous membrane can be at temperatures ranging from about -10.degree.C. to 50.degree.C.

Abstract: A polyethylene microporous film excellent in mechanical strength, permeability and productivity and having a very high reliability such that the safety of a battery may be secured even under severe circumstances which film has a crosslinked structure and has a porosity of 20-80%, a gel fraction of 1% or more, and an average pore diameter determined by the permeation method of 0.001-0.1 .mu.m, and a process for producing the polyethylene microporous film.

Abstract: Breathable microporous films are provided having controlled regional breathability with high WVTR regions and thicker low WVTR regions. The zoned breathable microporous films are be made by selectively applying adhesive to the microporous film.