Abstract: A slurry containing a precursor fiber convertible to carbon fiber and/or a carbon fiber and, based on 100 parts by weight of the fiber, 10 to 300 parts by weight of a thermosetting resin, e.g. phenol resin, is processed into a random web. This web may contain a pitch or an organic granular material. The web is hot-pressed between a pair of belts while curing of the resin is inhibited to prepare a prepreg sheet. This sheet is disposed, leaving a clearance, in a mold having ribs on a molding surface and heated over the melting point of the resin for expansion and complete cure to provide a porous composite sheet equipped with grooves. This porous composite sheet is carbonized or graphitized to produce a porous carbonaceous material for use as a fuel cell electrode material and so on. This porous carbonaceous material has high homogeneity, gas permeability, electrical conductivity, heat conductivity and mechanical strength.

Abstract: An anhydride-containing thermoplastic resin such as a styrene maleic anhydride copolymer is processed in a vented extruder in the present of a nitrogenous chemical blowing agent to both imidize at least a portion of the anhydride groups and remove volatile residues such as unreacted styrene monomer from the resin.

Abstract: A raw material formed by a mixture of, for example, soybean protein and water, is extruded by an extruder. Then, high-frequency electroconductive heating is performed by placing the material between a pair of electrodes and applying a voltage between the electrodes. As a result, a biodegradable molded article is obtained. In this method, biodegradable molded articles having a uniform structure are manufactured in a short period of time without increasing the cost of equipment or adversely affecting the working environment.

Abstract: A process and apparatus is provided for the moulding of a product formed from the mixing of a plurality of different feedstocks where different ratios of the feedstock materials are required in different areas or sections of a mould to produce a product with different properties in the different areas or sections of the final moulded product. A plurality of streams of the different feedstocks, each from separate feedstock supply vessels, are combined to form a mixed feedstock in a delivery head or heads prior to delivery to the mould. Separate pumps are provided to deliver, at constant speed of operation, a predetermined volume of each feedstock at a predetermined flow rate to the mould during a moulding cycle, driven by an electric motor operating at constant speed under constant load.

Abstract: A method of producing and the product of heat-proof laminate boards are disclosed. Each laminate board cut from a continuous laminate has a corrugated upper layer, a middle foam layer produced by spraying foam agent onto one side of the upper layer which will expand into shape automatically, a bottom layer having opposite edges folded in conformance to the corresponding edges of the upper layer so as to sealedly confine the foam in between the upper layer and bottom layer. The upper layer can be made of one of the materials including steel plate, PVC, PC, PP, aluminum plate, iron sheet. The bottom layer is made of materials including PVC film, PP film, papery film, fabric film, nylon film or wooden fiber sheet.

Abstract: A polyurethane seat pad having a center seat portion and bank portions therearound is molded by using a mold defining a cavity having a center region corresponding to the center seat portion and side regions corresponding to the bank portions, placing collecting vessels of expanded polyolefin in the side regions of the mold cavity, pouring a foamable polyurethane liquid for low hardness foam into the cavity between said collecting vessels, pouring a foamable polyurethane liquid for high hardness foam into said collecting vessels, and causing the foamable liquids to expand, thereby producing a polyurethane seat pad having the collecting vessels embedded therein. The expanded polyolefin is a crosslinked polyolefin foam having an index of surface wetting of at least 36 dyne/cm. The seat pad in which the bank portions have higher hardness than the seating portion and which is fully durable against repetitive loading can be produced to the desired configuration in a stable manner.

Abstract: A mixture in the form of slurry obtained from mixing a soybean protein, sugar and water is placed between a pair of electrodes. Then, an electroconductive heating process is applied to the mixture under an applied voltage between the electrodes for a predetermined time period, thereby obtaining the sheet-like biodegradable molded article. In this method, the biodegradable molded articles have a homogeneous structure and can be prepared in a short period of time without increasing the cost of equipment of creating unfavorable working conditions.

Abstract: A method of forming a three-dimensional object (38) is provided using a combination of molding and machining. In its most basic form, the method of the present invention is achieved by depositing a first layer of mold material (40) onto a support surface (20), machining a first cavity (42) into the first layer of mold material, depositing a first layer of construction material (52) onto the first layer of mold material such that an overlapping portion (52a) of the first layer of construction material fills the first cavity to form a first three-dimensional section of the object and such that a superposing portion (52b) of the layer of construction material covers the first layer of mold material, and machining the superposing portion (52b) to form a second three-dimensional section of the object. A larger object may be produced by repeating such steps in like sequence to form additional three-dimensional sections.

Abstract: A liquid resin composition prepared by mixing an ionic material and/or a chargeable material into a thermosetting or thermoplastic resin is injected into a mold having a predetermined inner shape, and a DC voltage is applied to the liquid resin composition to concentrate the ionic material and/or chargeable material on a desired portion or to distribute the ionic material and/or chargeable material continuously. Thereafter, the resin composition is thermally cured when the resin composition contains the thermosetting resin, or the resin composition is hardened by cooling when the resin composition contains the thermoplastic resin, thereby obtaining a molding having a predetermined shape.

Abstract: The disclosed oriented polyolefin film contains at least one voided layer. The voided layer contains an amorphous void-initiating polymer which, after orienting, is present as a separate particle inside the void. In the process for producing the polyolefin film, a molten blend comprising an olefin polymer and the amorphous polymer is extruded through a die at an extrusion temperature above the glass temperature or Vicat softening point of the amorphous polymer, the resulting film is drawn off on one or more rollers, and is then subjected to stretch orientation, followed optionally by thermofixing and a surface treatment.

Abstract: A foam having an internal structure comprising vertical walls, formed by curing individual rows of foam and subsequently layering multiple rows of foam to produce a billet or core is shown for use in the core of a structure where improved resistance to compression is desired, such as in the core of a surfboard, sailboard, or the like.

Abstract: There is disclosed a method for making a vibration dampener, the dampener cluding a body for disposition between two relatively movable members, the body being formed from a carrier of a gel material and particles having electrorheological properties embedded in the carrier with the particles electrically aligned and pseudo-bonded. The dampener is made by passing a current through a mixture of the particles and the carrier while the carrier cures into a gel material.

Abstract: An improvement process for producing a coated porous ceramic, ceramic composite or metal structure, wherein the impregnation step is carried out by (a) fluidizing said slurry with steam or heated water and spraying said shape with said fluidized slurry or (b) heating said slurry so as to reduce its viscosity and spraying said shape with said reduced viscosity slurry. Manufacture of a single component which functions both as a filter and as a heating element, is made possible by the process of the present invention.

Abstract: A flow regulator for catheters and similar devices and a process for their manufacture. The regulator consists of a tube having both cross-sectional and longitudinal dimensions of pre-determined precision, the regulator having extended tubular extremities for connecting to the catheter feed system. The manufacturing process includes the insertion of an axially mobile internal rod concentric with the tube, followed by molding stage by flattening the tube around the internal rod which is inside the tube, high frequency heating of the tube around the internal rod to heat internal regions of the tube, and then, after suitable cooling period has elapsed, withdrawing the internal rod to leave the tube with its precisely dimensioned bore.

Abstract: A solid phase extraction (SPE) filtration disk provides a glass fiber disk embedded with bonded silica/particulate chemistries homogeneously dispersed throughout the disk. Bonded silica/particulate chemistries are added to the glass fibers (and acidified water/solvent solution) during the formation of the glass fiber paper, as opposed to after the formation of the glass fiber paper. This enables homogenous dispersion of silica throughout the entire depth of the filtration disk.

Abstract: The invention relates to a process for the preparation of single-layered or multilayered molded articles from particles of polyisocyanate-polyaddition products by shaping a specified mixtures under heat and pressure. The mixture contains quasi-thermoplastic particles of polyisocyanate-polyaddition products and one or more processing aids.

Abstract: A method for forming an air chamber in a shoe sole includes disposing a film between two EVA sheet materials and hot-pressing the sheet materials so as to fuse the sheet materials together. The film prevents the sheet materials from being fused together so as to form a gap between the sheet materials. The air generated during hot-pressing and foaming process is accumulated in the gap so as to form an air chamber in the shoe sole such that the air chamber can be formed in the shoe sole without air bags and without injecting pressurized air into the shoe soles.

Abstract: A thermoplastic material, mainly to be used for splints and supports in orthopaedical, surgical and veterinary practice, is proposed for the fixation of body parts, the material including a copolymer of .epsilon.-caprolactone, polyurethane, and ethylene-butylene-styrene mixed with triallylcyanurate and oleic acid-imide, the copolymer mixture being gamma irradiated after processing, such that a degree of cross-linking of the molecules and a partially crystalline configuration results in a molded material with reproducible flexibility, elasticity and reciprocal stretch properties.

Abstract: Compounds containing ester groups and tertiary amino groups and optionally hydroxyl groups are made by reacting optionally hydroxyfunctional acetoacetic acid esters of monofunctional or polyfunctional alcohols (particularly polyfunctional polyether polyols) with primary/tertiary polyamines (particularly diamines). These compounds are useful as optionally incorporable catalysts for the isocyanate addition reaction in the production of polyurethane foams by the isocyanate polyaddition process.

Abstract: A molded closure for a liquid container comprising a thermoplastic elastomer and a blowing agent. The molded closure is particularly suitable for use as a synthetic wine cork in a wine bottle. The molded closure does not permit passage of oxygen into the container, does not absorb oxygen from the contents of the container, can be removed from the container using a corkscrew without significant expansion, crumbling or disintegration, does not significantly taint a liquid in the container, permits the container to be placed horizontally immediately after insertion of the molded closure, and can permanently retain printed matter on its surface.

Abstract: A shaped-article for use in producing a fiber-reinforced composite member is formed of short fibers and deformed fibers. The deformed fibers have a plurality of needle-like portions extending from a nucleus portion. The short fibers are orientated at random by dispersing the deformed fibers. The fiber shaped-article is formed by pouring a slurry of the short fibers and deformed fibers dispensed in a liquid into a mold, compressing the slurry and removing the liquid.

Abstract: Foams are prepared under reduced pressure and are subsequently encased in a material which will prevent ambient air from entering the cell voids. In the most preferred embodiment of the invention a polyurethane or polyisocyanurate foam is formed by mixing the polyol and isocyanate components under reduced pressure, allowing the gas within the foam to reach equilibrium at a lesser pressure then in prior systems. The need for blowing agents is substantially reduced and the K-factor of such foams is highly desirable. The foams are particularly well suited for use in refrigeration applications where the foams can be encased to prevent air from entering the cells after curing of the foam.

Abstract: The invention relates to membranes for facilitated ion transport in aqueous solutions. The membrane is an adduct of a heteropolysiloxane and a crown-ether, and contains certain ions such as picrate or fluoroborate. This membrane is efficient for the selective transport of potassium ions.

Abstract: An injection molding of a synthetic resin having a foamed injection pressure transmission material remaining in an injection pressure transmission channel can be produced with lower clamping force and with greater dimensional accuracy. The molding preferably has the following characteristics:(1) a thick-walled section is substantially connected to a gate;(2) an injection pressure transmission channel is formed in the inside of the thick-walled section;(3) the injection pressure transmission channel is filled with the foamed injection pressure transmission material;(4) the injection pressure transmission material comprises a foamable low molecular weight polymer:(5) an amount of the injection pressure transmission material is 1/10 or less of that of the synthetic resin by volume;(6) a viscosity of the low molecular weight polymer is 1/50 or less that of the synthetic resin at injection, and 0.5 poise or more;(7) a ratio of (a viscosity of the low molecular weight polymer at 120.degree. C.)/(that at 220.degree.

Abstract: A structural component such as a car door panel or door trim insert panel is produced in a single molding operation. For this purpose at least one premolded hard foam material block or member is inserted in a respective nesting mold cavity. Then an intermediate fiber material layer preferably in fleece form is placed on top of the foam material block. Then, a surface cover layer, such as a layer with a decorative exterior surface is placed on the intermediate fiber material layer with the decorative surface facing an upper mold section. The mold is then closed and the necessary heat and molding pressure are applied to laminate the intermediate fiber material layer to the cover layer. Then a nesting die applies additional pressure to the hard foam block for bonding the hard foam block to the intermediate fiber material layer.

Abstract: A process is disclosed for producing multiple-layer moulded bodies by injection of a laminate (16) composed of an essentially flexible, foil-like surface material (19) such as leather or textiles, and a foam layer (22) laminated on the back side of the surface material. Before the laminate is introduced in the injection mould, a separating layer (17) is applied on the surface of the foam material. The separating layer is composed of a separating agent that contains a mixture of an aqueous rubber dispersion and a aqueous silicone emulsion.

Abstract: Disclosed is a hydrophobic porous membrane with a polymer having fluorinated alkyl side chains held in physical contact with the surface of a polyolefin porous membrane in which the fluorinated alkyl side chains of the polymer are crystallized, as well as its manufacturing process. Also disclosed is a hydrophobic porous membrane with a fluorinated crosslinked polymer from a fluorinated monomer with a fluorinated alkyl side chain and a crosslinking monomer held in physical contact with the surface of a polyolefin porous membrane, in which the fluorinated alkyl side chains of the fluorinated crosslinked polymer are crystallized, as well as its manufacturing process. These porous membranes use polyolefin porous membranes having a higher mechanical strength and lower costs than the fluorinated polymer porous membranes and still provide superior hydrophobicity over polytetrafluoroethylene type membranes.

Abstract: A passive insulating system can provide highly effective protection in the presence of transient high temperatures. The system comprises, for example, a porous body forming a multiplicity of fine cells with a material having low thermal conductivity, a thermally absorptive liquid, providing an endothermic reaction in the presence of a catalyst, and a finely divided catalyst for the reaction uniformly distributed in the porous body. In preferred systems, the thermally absorptive liquid is para-hydrogen, the catalyst is granulated ferric oxide, and the liquid para-hydrogen changes to gaseous para-hydrogen, and from para-hydrogen to ortho-hydrogen in the presence of the ferric oxide catalyst, absorbing heat by its heat of vaporization and endothermic catalytic reaction and reducing heat transfer through the porous body.

Abstract: A method of forming in a mould an article using a thermoplastic sandwich material, which material has a core of a thermoplastic foam and one or two, optionally fiber-reinforced, covering layers of a thermoplastic resin, the method having the steps of providing in the mould a foamable thermoplastic synthetic material and said one or two fiber-reinforced covering layers, supplying a liquid to the mould at an elevated pressure and temperature, whereby the temperature of the thermoplastic synthetic material is raised to a temperature above the temperature at which the material foams, followed by lowering the pressure of the liquid and removing the liquid from the mould with foaming of the thermoplastic synthetic material.

Abstract: an apparatus for producing bodies of polymeric material having an outer shell and a core of foamed material is disclosed. The apparatus includes an extruder and accumulation chamber for extruding a tubular element, i.e., a parison, and a second extruder and accumulation chamber for injecting a foamable polymeric material for forming the core of the body inside the parison. The injection occurs inside the walls of a mold, which causes the tubular parison to undergo swelling due to the expansion of the foamable material until the parison conforms to the shape of the mold.

Abstract: A method of production of a plastic laminate having a protective layer on a foamed layer comprising coating plastisol containing a vinyl chloride resin or an acrylic resin having epoxy group and having average particle diameter of 0.05 to 5 mm and plasticizer as the essential components on the surface of vinyl chloride resin layer containing an organic foaming agent, then forming the combined layers by heating and foaming is provided. A plastic laminate having a protective layer of polyvinyl chloride having excellent surface strength, abrasion resistance and resistance to chemicals on a foamed layer can be produced efficiently.

Abstract: A composite article is prepared by intimately bonding a latex foam with a thermoplastic molded part containing polyphenylene ether, the latex consisting of the following components, relative to its total rubber content:I. 20-100% by weight of SBR latex with a minimum proportion of more than 15% by weight of styrene in the solid polymer, andII. 80-0% by weight of natural-rubber latex or other, synthetic latexes.The combination is vulcanized to form a product which exhibits cohesive rupture within the foam body, when the foam body is subjected to separation.

Abstract: A heat-resisting porous membrane comprises a porous polyolefin membrane having a crosslinked copolymer held on at least a part of the pore surfaces thereof, the crosslinked copolymer being composed of a monomer (A) comprising at least one multifunctional (meth)acrylate and a monomer (B) comprising at least one monofunctional (meth)acrylate having a hydrocarbon radical of 5 to 20 carbon atoms; and the heat-resisting porous membrane can be hydrophilized by additionally having a crosslinked polymer thereon. These heat-resisting porous membranes can be used in hot water for a long period of time without deteriorating the mechanical properties inherently possessed by the matrix of the porous membrane.

Abstract: An EVA insole manufacturing process includes a step of mixing an EVA resin with a foaming agent for producing a molding through squeezing and cutting procedures, and a step of heating the molding thus obtained in a mold so that it forms into a predetermined shape. Two or more moldings which respectively contain a different concentration of foaming agent or a different pigment color may be molded together so as to produce an insole which has different hardness and color at different parts thereof.

Abstract: An EVA insole manufacturing process includes a step of making a molding by injecting molding an EVA resin and foaming agent mixture without through crushing or cutting procedure, and a step of heating the molding thus obtained in a mold so that it forms into a predetermined shape. Two or more moldings which respectively contain a different concentration of foaming agent or a different pigment color may be molded together so as to produce an insole which has different hardness and color at different parts thereof.

Abstract: A method of producing a wood type golf club head which comprises molding and curing integrally an outer shell portion of a head main body having a hollow portion thereinside and equipped with a recess on at least one of the toe, back and heel sides thereof facing the hollow portion, from a synthetic resin as a main material, fixing a weight member having an adjustable weight into the at least one recess, packing a core member into the hollow portion, and fitting a sole plate to a sole portion of the club head.

Abstract: The present invention is directed to the discovery that certain additives of the type described in U.S. Pat. No. 3,726,952 effectively slow down the reaction rate of certain RIM systems based upon aliphatic amine terminated polyethers.

Abstract: A process for the production of composite bodies consisting of a polyurethane core and a polyurethane covering, with the core being positioned inside a mold so that an average distance of at least 0.5 mm exists between the surface of the core and the internal wall of the mold. The gap between the core and the internal wall of the mold is filled with a reaction mixture composed of a) a polyisocyanate component, and b) a polyol component. The polyol component b) must have a weight ratio of carbon to oxygen of at least 2.5:1.

Abstract: An injection mold for forming a thick-walled front cabinet which has a front frame panel and a cabinet portion integral with each other and which is used for an image display device containing a cathode ray tube therein. The mold has a cavity having a large depth corresponding to the large wall thickness of said cabinet, the depth of said cavity being reduced at at least a portion for forming an edge of said front frame panel contactable with said cathode ray tube, a sprue, a single runner communicating with said sprue, and a single film-type tunnel gate communicating with said runner and communicating with a portion of said cavity for forming an upper portion of said cabinet. First molten synthetic resin is first injected by a first cylinder of a sandwich injection molding machine through said tunnel gate into a portion of said cavity including said reduced depth portion.

Abstract: Foamable thermoplastic resin compositions are provided having vinyl chloride polymer, a graft copolymer having a superstrate grafted to a substrate wherein the superstrate has alphamethyl styrene, unsaturated nitrile, and unsubstituted styrene therein, and the substrate is a butadiene rubber, a rubber-free copolymer having alkylmethacrylate, vinyl aromatic, and unsaturated nitrile therein, and a chemical blowing agent. The foamable thermoplastic resin composition may be coextruded with a nonfoamed thermoplastic resin skin to produce a coextruded rigid foamed structure by a process of coextruding the skin and foamable thermoplastic composition. The composition and process are useful for making coextruded rigid foam structures which are useful in rigid foam applications such as foamed pipe and foamed sheet.

Abstract: A multihardness foamed seat having side rolls including one or more zones of a second polyurethane foam encapsulated in a first polyurethane foam is prepared by arranging the seat mould (10) so that the side roll well (12) is inclined in a direction parallel to its length, introducing a liquid first foam formulation into the side roll well, and then introducing a liquid second foam formulation within a time interval corresponding to between 0.01t to 1.5t where t is the cream time of the first foam formulation. The process is particularly useful for the preparation of automobile seats having side rolls.

Abstract: Display cushion (1), especially for pieces of jewellery, with a cushion layer (3) of foamed material.A novel jewellery display cushion, which can be simply and inexpensively manufactured but nevertheless fully meets the high aesthetic requirements of the jewellery trade and presents additional handling advantages, is made available by the fact that the cushion layer (3) consists of a thermoplastic plastic material and is hot-formed to produce a moulding corresponding to the shape of the cushion.A process for manufacturing such jewellery cushions is also the subject of the invention.

Abstract: A sandwich of a permeate fabric material within a folded sheet of semipermeable membrane is spirally wound together with a sheet of porous feed pathway material about a mandrel which, upon its removal, provides a central hollow region in the wound element. A single band of adhesive seals the outer end of the envelope, and once wrapping is completed, a thin layer of porous tape holds the winding tight. A porous small diameter tube is inserted into a pocket adjacent the fold in the semipermeable membrane material near the center of the winding and serves as a permeate discharge conduit. Axial ends of the spirally wound subassembly are sequentially potted in resin to complete the basic fabrication of the element. Communication with the feed pathway material is provided by drilling through the resin into the center hollow region.

Abstract: Improved durability and sharper chemical embossing images are obtained in a thick foamed thermoplastic floor structure by the use of an unfoamed inner layer. The floor covering is formed on a release paper and includes an unfoamed thermoplastic base coat, lower foamed thermoplastic layer, an unfoamed thermoplastic inner layer, an upper foamed thermoplastic layer and a clear coat. The enhanced chemical embossing is achieved by printing an inhibitor containing ink on the inner layer and below the upper foamed layer. Multilevel embossing is obtained by embossing both foamed thermoplastic layers or applying a growth-controlling agent to both surfaces of one foamable thermoplastic layer. The preferred embodiment includes a pearl platelet containing layer above the upper foamed layer to give the illusion of deeper embossing. The preferred embodiment also includes a wear coat of the reaction product of an aminoplast, a urethane and a polyol.

Abstract: A filtration medium especially useful in cross-flow type filtration systems comprising a length of porous strong substrate, preferably woven, and a thin porous membrane, such membrane being bonded to the strands of the substrate by islands of resin uniformly spaced apart and disposed generally between the substrate and the membrane. The islands of resin enhance the integrity of the composite during its use in a filtration system. A method and apparatus for the manufacture of the filtration medium is disclosed.

Abstract: Moldings made from polyolefin particle foams having a mean density of from 0.015 to 0.100 g/cm.sup.3 and having at least two different regions whose densities differ by from 0.005 to 0.030 g/cm.sup.3 have a transition zone between the different density regions having a thickness of not more than 25 mm. A method of forming the moldings, using removable mold dividing walls, is described.

Abstract: A method for forming a porous carbonaceous preform comprises, forming a mixture comprised of up to about 50 volume percent of furfuryl alcohol or tetrahydrofurfuryl alcohol, about 1 to 10 volume percent of a nonionic polyethylene oxide polymer ranging in molecular weight from about 100,000 to 5,000,000, about 30 to 80 volume percent of a carbonaceous material, and the balance water. The mixture is cast to form a body, and heated to decompose the polymer and form the porous preform. A molding composition for carbonaceous material comprises, up to about 50 volume percent of furfuryl alcohol or tetrahydrofurfuryl alcohol, about 1 to 10 volume percent of a nonionic polyethylene oxide polymer ranging in molecular weight from about 100,000 to 5,000,000, about 30 to 80 volume percent of the carbonaceous material, and the balance water.

Abstract: A polyurethane seat padding having a center seat portion and a bank portion on either side thereof is molded by using a mold defining a cavity having a center region corresponding to the center seat portion and side regions corresponding to the bank portions, placing collecting vessels of expanded polypropylene or polyethylene in the side regions of the mold cavity, pouring a foaming polyurethane liquid for flexible foam into the cavity between the collecting vessels, pouring a foaming polyurethane liquid for rigid foam into the collecting vessels, and causing the foaming liquids to expand, thereby producing a polyurethane seat padding having the collecting vessels embedded therein.

Abstract: A membrane for a filter device or a device for gas or liquid separation, the membrane being constituted by a porous structure made of at least one material selected from sintered ceramic, sintered metals, microporous carbon, microporous glass, and polymers, said structure including at least one microporous layer, wherein the entire outside surface and inside surface of the pores of said structure is covered by a thin and continuous film of a polyphosphazene, the thickness of said film lying in the range 0.01% to 10% of the mean diameter of the pores of said microporous layer.

Abstract: A process for forming a porous polymer film formed by allowing a solvent to evaporate from a solution of polymer containing water and alcohol. It is possible to form a porous polymer film in which the size and distribution of the pores are uniformalized. Also described is a process for producing a composite film in which the pores of the porous polymer film are filled with a functional low molecular substance such as liquid crystal or dye so that the dispersion diameter of the functional low molecular substance and the distribution of the same are uniformalized. In the production of the above-mentioned porous polymer film, the size of the pores on the porous polymer film can be controlled by controlling the humidity of the forming atmosphere or the water content in the solution of polymer.