Abstract: A process of debinding a ceramic product utilizes a furnace for heating the ceramic product therein in the presence of a surrounding gas so as to remove an organic binder contained in the ceramic product. The ceramic product is continuously heated to an elevated temperature during which the organic binder is decomposed to generate a cracked gas. The process monitors the condition of the cracked gas and controls, depending upon the monitored condition, to vary a temperature gradient at which the ceramic product is heated and at the same time to vary an amount of the surrounding gas being supplied to the furnace in such a manner as to remove the organic binder successfully from within the ceramic product without leaving any unacceptable defect therein.

Abstract: Using an organic binder containing at least one water-soluble thermoplastic organic polymer and at least one water-insoluble thermoplastic organic polymer, the water-soluble thermoplastic organic polymer is extracted by debinding treatment in which a plastic molded part such as injection molded part and water are brought into contact with each other to prevent the occurrence of cracks in the molded part. Removal by extraction of the water-soluble thermoplastic polymer reduces the amount of the organic binder contained in the molded part sufficiently, thus preventing the softening and deformation of the molded part at the time of optionally heating and removing the remainder of the organic binder and/or sintering of the molded part and also preventing the occurrence of swelling and cracks by the effect of guide passage formed by the extraction of the organic polymer.

Abstract: Objects of thermoplastic polymer foam such as, e.g., sheeting of polyolefins such as polyethylene, are treated at elevated temperatures effective to rapidly purge the foam of a substantial portion of the residual blowing agent. Significant economies are achieved by reducing the amounts of residual blowing agents (such as flammable, toxic or environmentally hazardous gases) to levels presenting no fire hazard or other safety hazards in times substantially less than required in conventional aging under ambient conditions. The processes can be carried out in ovens or other heating zones which form continuations of the basic production line, with the extracted blowing agents recycled or disposed of by combustion.

Abstract: Plastic molded articles having low friction and excellent wear resistance are produced by treating the surface of the plastic article with an aqueous solution of an inorganic fluoride such as hydrogen fluoride. Plastic articles which can be made in accordance with the invention include plastic brake pistons, bearings, motors and drives, commutators, slip ring alternators for DC drive motors, thrust washers, spacers and reactors, clutch plates, electrical switching equipment with sliding parts, gears, pulleys for belt drives, such as cog belt pulleys, V-belt pulleys and poly V-belt pulleys, gas meter discs, and the like. In addition to the treatment step, the plastic articles are neutralized, washed and dried.

Abstract: A method of manufacturing ceramic products. This method comprises the steps of mixing ceramic powder, organic materials imparting formability to the ceramic powder, and a first solvent, thereby preparing a mixture, shaping the mixture thereby forming a product of a simple shape, drying the product, immersing the dried product in a bath of a second solvent, thereby plasticizing the product, and re-shaping the plasticized product.

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 process for rapidly removing the binder from a greenbody composed of a sinterable powder dispersed within a polyacetal binder is achieved by contacting the molded ceramic greenbody with an acid which depolymerizes the polyacetal binder.

Abstract: Shaped hydrogel articles such as soft contact lenses are prepared by (1) molding or casting a polymerization mixture comprising: (a) a monomer mixture comprising a major proportion of a hydrophilic (meth)acrylate ester such as 2-hydroxyethyl methacrylate, an alkyl (meth)acrylate wherein the alkyl group contains at least four carbon atoms, and a cross-linking monomer; and (b) a water-displaceable diluent, wherein said diluent has a viscosity of at least 100 MPa Sec at 30.degree. C., and wherein said diluent consists essentially of a boric acid ester of certain dihydric alcohols, said dihydric alcohols having Hansen polar (w.sub.p) and Hansen hydrogen bonding (w.sub.h) cohesion parameters falling within the area of a circle defined as having a center at w.sub.h =20.5, w.sub.p =13, and a radius of 8.5, to produce a shaped gel of a copolymer of said monomers and said diluent, and (2) thereafter replacing said diluent with water.

Abstract: The method of making a plastic article having a plurality of small openings which utilizes a plurality of thin plastic tubular members combined together in a side-by-side relationship forming an assemblage. Each tubular member has an exterior layer of a first plastic and a core of a second plastic. The second plastic is to be dissolvable by a solvent. This assemblage is passed through a furnace with the result that the assemblage is drawn into a thin filament. Once cooled, the thin filament is cut into segments of a desired length and these segments are placed within a solvent bath for a sufficient period of time in order to affect complete removal of the second type of plastic resulting in producing of a plurality of small, through openings within each section.

Abstract: A method of casting a powdered material. A slurry is formed by dispersing metal powder or ceramic powder into a dispersing medium mainly consisting of a substance extractable by a liquid or supercritical carbon dioxide and having a melting point between 0.degree. C. and 100.degree. C., and the slurry is poured into a liquid non-absorbing mold where the slurry is cooled to freeze and solidify into a molding. The main constituent of the dispersing medium in the molding is extracted and removed by the liquid or supercritical carbon dioxide.

Abstract: A method for removing a paraffin wax based binder containing a fatty acid from a green article, wherein the article is made of material selected from the group consisting of ceramic powders and metallic powders, which comprises heating the article in a non-oxidizing atmosphere in a furnace by raising the temperature at a rate of about 0.5.degree. C. to 1.0.degree. C. per minute to a first temperature of about 50.degree. C. to 80.degree. C. and thereafter maintaining the first temperature for about 30 to 90 minutes to essentially completely melt the binder, raising the temperature from the first temperature at a rate of about 0.5.degree. C. to 1.0.degree. C. per minute to a second temperature of about 200.degree. C. to 225.degree. C. and thereafter maintaining the second temperature for about 30 to 90 minutes to essentially completely vaporize the paraffin wax, raising the temperature from the second temperature at a rate of about 0.5.degree. C. to 1.0.degree. C. per minute to a third temperature of about 260.

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: To automate the roughening of the peripheral surface of a shoe upper in the region to be soled, the application of adhesive along such surface and a final deburring operation, prior to injection molding the last supported shoe upper in the region of lateral side mold elements is measured at the peripheral curvature to determine a curved line of spacial coordinates and angles of curvature starting at a preselected null point, and the values are stored. Another last supported shoe upper is moved by a rotary turntable to be scanned at selected points along its periphery for comparing the selected points to the spacial coordinates and angles of curvature. Any deviation therefrom is adapted to a second preselected null point, after which the shoe upper is guided by a computer controlled robotic device along the curved line starting from the second null point.

Abstract: A method for casting a metal or ceramic powder which comprises casting a slurry of the metal or ceramic powder suspended in a dispersion medium containing at least 10 wt. % of a liquid extractable with a supercritical fluid or a liquefied gas into a porous mold, keeping the slurry placed in the porous mold at a temperature not lower than the melting point of the dispersion medium, and extracting at least 10 wt. % of the dispersion medium with the supercritical fluid or liquefied gas to impart a formability to the extracted body.In the method of the invention, since the volume change of the dispersion medium due to phase change does not occur, the internal strain and deformation of the molded body occur little. As a result, the sintered body obtained has a highly dimensional accuracy.

Abstract: Graphite blocks are produced by a process wherein one or plural polymer films having a thickness of from 1 to 400 .mu.m and selected from aromatic polyimides, aromatic polyamides and polyoxadiazoles are heat treated to obtain carbonaceous films. A plurality of the carbonaceous films are hot pressure under certain conditions to obtain thick graphite blocks. The blocks have a remarkably improved rocking characteristic and are useful as radiation optical elements such as X-ray or neutron ray monochromators or filters. The blocks may be curved to obtain bent-type graphite articles.

Abstract: A method for manufacturing a sintered body is provided, comprising the steps of dispersing powdery silicon nitride and a sintering assistant into a first dispersion medium composed mainly of substance capable of being extracted by supercritical fluid to form a first slurry and casting the first slurry to form a compact; dispersing powdery material into a second medium composed mainly of substance capable of being extracted by the supercritical fluid to form a second slurry and coating the second slurry on the surface of the compact to form a film layer; dipping the compact covered with the film layer in the supercritical fluid to extract the first dispersion medium and the second dispersion medium, respectively from the compact and the film layer; heating the compact from which the first and second dispersion mediums have been removed to form the film layer into a film layer impermeable to gas; and sintering the compact covered with the film layer impermeable.

Abstract: In the process for making gypsum fiberboard the boards are formed or molded rom a mash containing calcium sulfate dihydrate and fiberous material. By heating and subsequently cooling the boards the dihydrate is first converted into the hemihydrate and subsequently recrystallized again to the dihydrate. Known processes require day line setting times which are economically disadvantageous. According to the present invention these times are shortened by pulling or drawing water, an aqueous solution or a water containing mixture through the boards after the cooling step. Advantageously a setting accelerating agent can be dissolved in the water. By these features the setting time can be shortened to less than two hours. By addition of a binding agent, e.g. starch, to the fluid drawn through the boards the strength of the boards is increased.

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: The invention relates to a process for the treatment of surfaces of highly oriented polyolefin objects, obtained by converting a solution or melt of a linear polyolefin with a weight average molecular weight of at least 400.000 g/mol, at a temperature above the dissolution temperature, respectively above the melting temperature, into a shaped object, converting this object into a gel-object by cooling, and stretching the gel-object at elevated temperature optionally after full or partial removal of the solvent, in which the surface of the object is contacted with a solution of a radical-forming compound and that the object is then exposed to a temperature of at least 30.degree. C. for at least 1 minute.

Abstract: This invention is a method and an apparatus for rapidly devolatilizing a product of a polymerization process containing at least one volatile material. The product is initially devolatilized in a high temperature zone, and the foamed devolatilized product is separated into a gas and a liquid polymer phase and rapidly removed therefrom to minimize depolymerization and degradation of the polymer. The partially devolatilized product is further devolatilized by feeding it into a rotatable chamber which is rotated at a sufficient angular velocity to create a high gravitational field to form a vapor and a polymer liquid pool.

Abstract: The adhesion of highly oriented polyolefin objects, in particular polyethylene filaments, to e.g. polar, polymer matrices is improved by contacting the surface of the object with a solvent for 0.5-2 minutes at a temperature above the dissolution temperature of the polyolefin.

Abstract: A process is disclosed for producting thin stretched films having a thickness between 0.1 and 20 .mu.m from polyolefins of ultrahigh molecular weight by dissolving the polyolefin in a solvent, shaping the solution at a temperature above the solution temperature of the polyolefin to a tape, cooling the tape to a temperature below the solution temperature to obtain gelation and stretching the gelled tape. In this process the gelled tape is initially subjected to a preliminary orientation in one direction, under solvent removal, and is then stretched in a direction essentially perpendicular to the direction of preliminary orientation, at elevated temperature, followed by final stretching to obtain the finished thin films. This process makes possible the production of films which are free from pores, that is to say transparent and which posses high Young's moduli, high tensile strengths and favorable values for elongation at break.

Abstract: Removing chloroprene dimers from polychloroprene by feeding to a screw extruder a polychloroprene latex and coagulating the latex in the extruder, feeding the coagulated latex to a dewatering zone and discharging the coagulated polychloroprene through a flow restriction which heats and pressurizes the polychloroprene to an area of reduced pressure to form a porous crumb. Also, the flow restriction applies back pressure sufficient that the water in the polychloroprene is forced out of a vent port. The polychloroprene crumb discharged from the extruder is heated to strip chloroprene dimer therefrom.

Abstract: There is disclosed a method for eliminating an organic dispersion medium from a molded product obtained by plasticizing-molding or casting-molding of metallic and/or ceramic powders wherein the elimination is by extraction by liquid carbon dioxide at a temperature not lower than -30.degree. C. and not higher than -31.1.degree. C. The method prevents nonuniform volumetric decrease of the molded product to be otherwise caused by the extraction of the organic dispersion medium, while also making it possible to completely eliminate the organic dispersion medium without causing residual strain or deformation in the molded product.

Abstract: A stereolithographic method which employs an ultraviolet-curable liquid composition adapted to cure rapidly to a lightly cross-linked solvent-swellable three-dimensional complexly-shaped polymeric thin-walled element constituted by heat-softenable solid polymer upon exposure to ultraviolet dosage in the range of about 0.1 to about 10 Joules per square centimeter and which possesses reduced distortion comprises, from 20 to 80 weight percent, of a resinous polyacrylate or polymethacrylate dissolved in a combination of 10 to 45 weight percent of a liquid polyacrylate or polymethacrylate, which is preferably trifunctional, and 10 to 45 weight percent of liquid N-vinyl monomer, preferably N-vinyl pyrrolidone. Thus, the weight ratio of polyacrylate: polymethacrylate: N-vinyl monomer is about 1:2:2 to about 8:1:1. One of the foregoing polyacrylates or polymethacrylates is a polyacrylate and the other is a polymethacrylate so that good cure speed is accompanied by good distortion resistance.

Abstract: A method for treating porous polytetrafluoroethylene and other types of synthetic materials having low surface tension to render the material suitable for use in bonding to living tissue. The synthetic material is enveloped with a liquid of sufficiently low surface tension to permit the liquid to enter the pores of the material. The liquid has a sufficiently low gas content to enable the liquid to absorb or displace essentially all gas nuclei held in the pores of the material as the liquid fills essentially all pores. After the low surface tension liquid has permeated all pores of the porous material, such liquid is replaced with a solution compatible with the body fluid and in which proteins have a low solubility to render the material suitable for implant. When such material is placed in contact with exposed tissue, an immediate bond is formed which permits implanting the material without the need of sutures to hold the material in place.

Abstract: A synthetic vascular prosthesis comprises a hollow tubular base member having a multitude of continuous pores and formed of an elastomer material, and a hydrogel layer formed on the inner surface of the base member. The hydrogel layer is partly embedded in the inner portion of the base member at the pores, thereby permitting anchoring adhesion between the hydrogel layer and the base member. A method for manufacturing the synthetic vascular prosthesis is also disclosed, in which the formation of pores in the base member is effected by two separate steps and the hydrogel layer is formed after formation of an inner porous portion of the base member.

Abstract: An ultraviolet radiation screening composition for on-line surface impregnating hot polycarbonate sheet. The composition includes an ultraviolet radiation screener and carrier solution which contains respective amounts of dipropylene glycol methyl ether, tripropylene glycol methyl ether, 1,2 propanediol and 1,4 butanediol. The carrier solution provides a desired level of volatility and aggressiveness for on-line surface impregnation of hot aromatic polycarbonate sheet and film.

Abstract: Methods for preparing highly conductive, oriented polymers are disclosed. In the preferred embodiment, solution of conductive polymer is cast onto the surface of a stretchable support material, and oriented polymer is produced by removing solvent from the solution and stretching the support material. The invention is particularly useful for preparing oriented films of polyaniline which films have been shown to exhibit conductivities in the range of 300-2500 S/cm.

Abstract: Method for manufacturing a sintered body with high density comprises: turning first powder into a first slurry by dispersing the first powder in a first dispersion medium composed mainly of substances capable of being extracted by supercritical fluid and forming a compact which contains the first dispersion medium, by casting the first slurry; turning second powder into a second slurry by dispersing the second powder in a second dispersion medium composed mainly of substances capable of being extracted by supercritical fluid, and forming a film layer by coating the surface of the compact with the second slurry; extracting and removing the substances contained in the compact and the substances contained in the film layer by means of the supercritical fluid; turning the film layer on the surface of the compact into an impermeable film layer to gas by heating the compact, from which the substances have been extracted and removed; and applying a hot isostatic pressing process to the compact, the film layer on the

Abstract: A power-plant clarifier sludge having the following dry composition:______________________________________ SiO.sub.2 2 to 30 weight percent, Fe.sub.2 O.sub.3 2 to 20 weight percent, Al.sub.2 O.sub.3 0.5 to 5 weight percent, CaO 15 to 50 weight percent, MgO 1 to 8 weight percent, MnO 0.01 to 0.5 weight percent, Na.sub.2 O 0.1 to 0.5 weight percent, K.sub.2 O 0.1 to 1 weight percent, SO.sub.3 in sulfate 0.1 to 2 weight percent, and CO.sub.2 in carbonate 5 to 40 weight percent; ______________________________________is used in the desulfurization of power-plant flue gas and the desulfurization slurry is dewatered and pressed into construction blocks.

Abstract: A method of vaporizing and removing a binder from a powder-molded product containing the binder, which method comprises:coating the greater part of the surface of said powder-molded product with a thin resin film having air-tightness thereby leasing an exposed surface portion;pressurizing the thus-coated surface portion of the pressure-molded product hydrostatically;vaporizing the binder in the power-molded product under said hydrostatic pressurization; andremoving the vaporized binder to the exterior of the power-molded product through said exposed surface portion not coated with the thin film.

Abstract: A melt spun film or tape of a thermoplastic fibre-forming polymer comprising spaced fibrils fo the polymer which are substantially aligned to the longitudinal axis of the film. Such aligned, spaced fibrils being interconnected to each other in a random manner.

Abstract: A carbonaceous cylindrical body including a composite body of a carbonized material of a thin paper-like supporting body having a strength ratio of lengthwise direction to widthwise direction of 2 to 10 and obtained by manufacturing a paper-like body so that its carbonizable fibers are oriented and a carbonaceous matrix having an optically isotropic structure under a polarizing microscope and which shows a carbon content of at least 85% by weight, an oxygen gas permeation coefficient of 10.sup.-2 to 10.sup.-7 cm.sup.2 /sec. under a partial pressure of oxygen of 1 atmosphere and a bulk density of from 1.4 to 1.9 g/cm.sup.3. A process for producing the carbonaceous cylindrical body is also provided.

Abstract: A process to produce oriented, crystalline polyaniline films using simultaneous heat treatment and stressing of polyaniline films. Films stressed while being held at elevated temperatures (T.gtoreq.110.degree. C.), showed anisotropic x-ray, IR and visible optical response.

Abstract: A method for refining powders comprising the steps of: (a) adding polytetrafluoroethylene powders to non-oxide ceramic powders to form a mixture by mixing; and (b) heating the mixture in non-oxidizing atmosphere to convert oxides existing on the surface of the non-oxide ceramic powders into gaseous fluorides, and removing gaseous fluorides. The fluororesin is a polytetrafluoroethylene resin. The heating temperature in the non-oxidizing atmosphere is 500.degree. C. to 1300.degree. C.

Abstract: A method for preparing a soft ocular lens, which comprises machining a machinably hard polymer blend body composed essentially of a soft lens material and a hard polymer into an ocular lens shape, and removing the hard polymer from the shaped product.

Abstract: Fully aromatic polyamide (aramid) resins can be cast into ultraporous and microporous membranes by forming a solution of the resin in an amount sufficient to cast a coherent membrane, diluting the solution with a liquid pore modifier which is a nonsolvent for the resin so as to produce a metastable dispersion of the resin, adding a precipitant to form a turbid casting dope, casting the dope onto a surface, and gelling the so-cast film.

Abstract: This invention relates to a method of treating liquid-wet polycarbonate membranes to improve gas separation properties.

Abstract: An asbestos-free insulating material suitable for use as a header in molten metal casting. The material is made from a dry mixture comprising lime, siliceous component, delaminated vermiculite or spodumene or lithium aluminate or mixtures thereof, and optionally, wollastonite and organic fiber. The dry mixture is mixed with water to form a slurry, shaped, heated in the presence of steam, and dried to remove free water.

Abstract: A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, whereafter the product may be sintered.

Abstract: A method of forming hollow, porous elastomeric bodies and hollow, duo-layered elastomeric bodies wherein one layer is porous and contiguous with the other layer which is solid by (a) coating a surface of a mandrel with a coating liquid, (b) adhering a layer of water-elutable particles onto the coated mandrel surface, (c) applying a layer of fluid elastomer composition to the particle-coated mandrel surface wherein the elastomeric composition is capable of forming a water-insoluble elastomer, (d) causing said elastomeric composition to form a cohesive mass while in contact with the particle-coated mandrel surface, (e) dissolving said elutable particles from the cohesvie mass with a water-based solvent, and (f) removing the cohesive mass from the mandrel. The coating liquid comprises water and may also further comprise a wetting agent and/or a sugar. The invention also relates to the method wherein the water-elutable particles are adhered to the mandrel surface by heating the mandrel surface.

Abstract: Shaped hydrogel articles such as soft contact lenses are prepared by (1) molding or casting a polymerization mixture comprising: (a) a monomer mixture comprising a major proportion of a hydrophilic (meth)acrylate ester such as 2-hydroxyethyl methacrylate, and a cross-linking monomer; and (b) a water-displaceable diluent, wherein said diluent has a viscosity of at least 100 MPa Sec at 30.degree. C., and wherein said diluent consists essentially of a boric acid ester of certain dihydric alcohols, said dihydric alcohols having Hansen polar (.delta..sub.p) and Hansen hydrogen bonding (.delta..sub.h) cohesion parameters falling within the area of a circle defined as having a center at .delta..sub.h =20.5, .delta..sub.p =13, and a radius of 8.5, to produce a shaped gel of a coploymer of said monomers and said diluent, and (2) thereafter replacing said diluent with water.

Abstract: A method for preparing porous membranes containing a homogeneous microporous structure and narrow pore size distribution which are useful for ultrafiltration, distillation and substrates for composite membranes, including preparing films, pellets or sheets containing alternating microlayers of high density polyethylene and polystyrene, recoextruding these films, pellets or sheets, pulverizing into fine granules or powder, compression molding or sintering into thin films, immersing these films in a solvent bath into which one component is selectively dissolved and separating the resultant porous membrane from the solvent.

Abstract: A process for producing a filter including a microporous membrane and a supporting structure connected thereto, including producing a mold for the membrane and the supporting structure, filling the mold with a molding material whose solubility can be changed by high energy radiation, and forming the micropores by partial irradiation of the membrane with high energy radiation and removal of the regions having increased solubility. The filter produced according to the above method is a unitary structure with the supporting structure integrally connected to the membrane.

Abstract: A method for preparing an asymmetric, semi-permeable membrane containing a uniform microporous structure for gas and liquid separation, including forming a dense separation on one major surface of a microporous support structure. The microporous support structure is initially formed as a solid unitary film, fiber or sheet by the simultaneous extrusion of at least two streams of heat-plastified polymeric materials including at least two differentially soluble polymeric materials. The separation layer can be formed on the support structure prior to or after the soluble polymeric material has been dissolved out of, as by leaching from the solid support structure to form the microporous support for the separation layer. Preparation in this manner greatly reduces the tendency to form undesiralbe pinholes in the membrane.

Abstract: A process for producing a relatively thick microporous ultra-high-molecular-weight polyolefin membrane, including the steps of: (1) preparing a solution of an ultra-high-molecular-weight polyolefin having a weight-average molecular weight of 5.times.10.sup.5 or more; (b) extruding the solution from a die while rapidly cooling it in advance to its gelation temperature or below, thereby forming a gel-like sheet; (c) removing at least 10 wt % of the solvent from the gel-like sheet so that the gel-like sheet contains 10 to 90 wt % of the ultra-high-molecular-weight polyolefin; (d) stretching the gel-like sheet at a temperature equal to or lower than that which is 10.degree. C. above the melting point of the ultra-high-molecular-weight polyolefin; and (e) removing the residual solvent from the stretched product.

Abstract: A method of manufacturing hydrogel dressings from synthetic and natural polymers by polymerization and cross-linking involves pouring aqueous solutions of synthetic polymers, such as polyacrylamide and polyvinylpyrolidone, their monomers or their mixtures, natural polymers, such as gelatine or agar, or their mixtures and, possibly, plasticizing agents, such as poly/ethylene glycol/, poly/propylene glycol/ and silicone oils, of the following composition: 2-20 percent by weight of synthetic polymers, not more than 5 percent by weight of natural polymers, not less than 75 percent by weight of distilled water and 1-3 percent by weight of plasticizing agent, into a mould imparting a shape to the dressing, tightly closing in that mould and subjecting to an ionizing radiation dose not smaller than 25 kGy.

Abstract: In a process of producing a high-temperature resistant film or a polyimide polymer, a solution of the polymer in an organic solvent is caused to flow out through a slots spinneret of a film forming arrangement and to coagulate in an aqueous precipitation bath containing the organic solvent. The film made up of coagulated liquid is stripped, the organic solvent is removed and the film is dried. In order to attain sufficient strength properties without subsequent orientation and, thus, achieve a better dimensional stability at elevated temperatures, the liquid film formed in the slot spinneret is allowed to fall directly freely into the aqueous precipitation bath through a short air gap. The film formed is drawn off the precipitation bath and is subjected to a subsequent thermal treatment to achieve a transparent homogeneous film. The organic solvent is then removed by treatment with an aqueous extraction agent, and the film is finally dried.

Abstract: A process for producing a porous ceramic filter for use in the filtering of particulates from diesel exhaust gases, and the filter so produced, in which a foamable ceramic composition based upon an aluminosilicate hydrogel binder is expanded into a self-supporting, open-celled porous body of desired shape by virtue of in situ reaction between components of the composition, and thereafter treated to substantially reduce its alkali metal content and fired to produce ceramic bonds, the process further preferably providing on the intended outlet surface of the filter a thin porous ceramic membrane layer whose pores have an average diameter less than that of the pores within and at other surfaces of the ceramic filter.