Abstract: A process for producing an expanded or foamed body of a fluorocarbon resin comprising molding the resin in a molten state in the presence of a depolymerizable polymer, polyether or polycarbonyloxy compound.

Abstract: A ribbed, porous tube suitable for use as a vascular graft prosthesis is prepared by scoring a stretched or unstretched tube of PTFE, stretching the tube at 200.degree.-320.degree. C. to develop the desired porosity, and heat setting the scored, stretched tube at 327.degree.-450.degree. C. while restraining the tube from axial shrinkage.

Abstract: A method of constructing a gate valve includes the step of placing a slidable valve gate (46) in a valve cavity (16) between aligned holes (21) of a valve body (10) in a position for closing a fluid passage through the body. Removable mold fixtures (22, 24 and 26) are attached at each opening into the valve body for covering it and thereby preventing liquid material from flowing out of the hole. The valve body (10) and its attachments are heated and a molten resinous material is inserted into the valve cavity so as to surround the aligned holes (21) and to fill spaces between the body (10) and the valve gate (46). The valve body and the resinous material are then allowed to cool so that the resinous material hardens to form a valve liner in which the valve gate moves for opening and closing the fluid passage (80). The mold fixtures are shaped to form flange rings (76, 78) outside the valve-body openings and to form a cavity (84) for packing material (86). A fluoropolymer is used as the resinous material.

Abstract: A release agent applicator for a copying machine in which voids in the release agent contained in the applicator are substantially eliminated, thus providing an improved spreading performance of the release agent onto a fixing roll of the copying machine. The release agent applicator is made of a porous polyethylene tetrafluoride tube, the pores of which are partially closed except in areas where the release agent is to ooze out onto the fixing roll. Those partially closed pores in the tube are partially closed by a flattening operation so that they cannot draw release agent thereinto by capillary action.

Abstract: A method of producing unitary hollow structures, for example radomes, comprised of fiber reinforced plastic with a large percentage of the fibers being randomly oriented in directions essentially parallel to the wall surfaces of the structures and with at least one surface having grooves to reduce microwave reflection is presented. The structures are produced by packing a layer of fiber filled polymeric material in powder form around a mandrel which may have a pattern of grooves of ridges in its outer surface. The mandrel and packed powder are subjected to isostatic pressing to properly orient the fibers and achieve a density increase and powder cohesion. The pressed structure is sintered and the outer surface subesquently machined to a finished contour.

Abstract: Novel particulate polymeric materials which can be arranged in a predetermined three dimensional pattern in or on a surface, fused and cooled to provide fused, three dimensional polymeric articles. The particulate polymeric materials have the capability to provide a release coating about the fused polymeric article which permits removal of the article from the surface carrying the article.

Abstract: The preferred embodiment provides such a hydrogen-stored electrode extremely useful for application to the cathode of alkaline battery. It makes it possible to manufacture such a useful hydrogen-stored electrode molded into electrode form after activation of hydrogen-stored alloy by means of hydrogen generated by immersion of blends into solution, in which the blends is composed of hydrogen-stored alloy and additives that generate hydrogen through their reaction with the above solution.

Abstract: A radome being a unitary structure comprised of a fiber reinforced plastic is produced with a large percentage of the fibers being randomly oriented in a plane parallel to the inner surface of the radome. The radome is produced by packing a layer of fiber filled powder around a mandrel having its outer contour resemble the inner contour of the radome. The mandrel and packed powder are then subjected to isostatic pressing to properly orient the fibers. The radome is finished by sintering the powder and removing the finished form from the mandrel.

Abstract: The present invention relates to a method of making a tape suitable for impregnation into a porous metal matrix which generally comprises the steps of mixing a liquid dispersion of PTFE with a coagulant to form a paste, placing the paste between a layer of supporting material and a layer of filter paper to form a sandwich, compressing the sandwich, transferring the sandwich to a gauze-like material so that the filter paper layer of the sandwich is adjacent the gauze-like material, applying a vacuum to the gauze-like material and adjacent filter paper layer to remove some excess liquid from the paste, and removing the layer of filter paper from the sandwich to leave a tape comprising PTFE and liquid and a layer of supporting material adjacent the tape. The method of the present invention may be used to apply, by impregnation, a PTFE based composition, which may include various fillers therein, to a porous metal matrix or interlayer.

Abstract: A method for producing a thermoplastic resin sheet or a filler-containing thermoplastic resin sheet by which method a difficultly-workable thermoplastic resin as well as an ordinary thermoplastic resin can be formed into a sheet and various kinds of fillers can be compounded into the sheet. The method is characterized in that a thermoplastic resin or a composition of a thermoplastic resin and a filler is fed in powder or preformed sheet form between a pair of tensioned endless belts disposed parallel and travelling together around a set of rolls, the endless belts being heated by being brought into surface-to-surface contact with heating rolls while travelling along a path having at least one bend formed by the heating rolls, and the material is heated and compressed between the endless belts and melted into an integral body at or above the melting point or softening point of the thermoplastic resin.

Abstract: A radome combines low dielectric constant and dissipation factor at microwave frequencies with mechanical strength and rigidity as well as resistance to ablation and rain erosion at hypersonic velocities in the range of Mach 4 to 6. Continuous filament glass fabric and/or strand is saturated with PTFE dispersion. Layers are applied to a mandrel and cold isostatically pressed. The pressed layer may be machined between applications and subsequent pressings. After all layers are applied and pressed, optionally including an outer ablation resistant random fiber reinforced PTFE composite, the densified structure is heat cycled above the crystalline melt point of the polymer to maximize mechanical properties.

Abstract: A method for manufacturing a metal sintered body disclosed herein is characterized by the use of steps of: mixing 70 to 90 weight % of self-fluxing alloy powder and 10 to 30 weight % of metal powder of high melting point having a higher melting point than that of the self-soluble metal powder and in which the self-fluxing alloy powder is liable to be deposited thereon to obtain a metal powder having a sintering property; using a material in which 1 to 10 weight % of plastic binder is kneaded with the metal powder having a sintering property to obtain a molded body having a predetermined shape; and sintering the molded body at a temperature in excess of a liquid phase line of the self-fluxing alloy powder.

Abstract: A semisintered polytetrafluoroethylene article which is prepared by heating an unsintered polytetrafluoroethylene article at a temperature of at least the melting point of a sintered polymer, the article having an endothermic curve at a temperature of 345.+-.5.degree. C. on a crystalline melting chart measured with a differential scanning carolimeter and a crystalline conversion of from 0.10 to 0.85 defined by heat of fusion of the unsintered, semisintered and sintered polymer, and the crystallinity of the semisintered article measured by X-ray diffraction being from 80 to 93%. The article is expandable biaxially to afford a porous polytetrafluoroethylene material having an almost unporous surface.

Abstract: A water-condensing heat exchanger recovers heat from a hot flue gas, subjecting tubes of the heat exchanger to substantial thermal expansion and contraction, and corrosive constituents in the flue gas require that metal tube sheets be thoroughly insulated from the flue gas during operation in a water-condensing mode. The heat exchanger is constructed by heat-forming edge portions of holes in plastic sheets through holes in tube sheets, temporarily plugging the plastic-lined holes to limit diametrical reduction, and entering tubes through the plastic-lined holes sufficiently shortly after unplugging the holes that further diametrical reduction of the holes causes them to grip and fixedly locate the tubes relative to the tube sheets. The method of manufacture also concerns providing a fluroplastic coating, e.g., polytetrafluoroethylene, on the interior elements of the heat exchanger to inhibit corrosion thereof; such coatings are hydrophobic thus allowing falling condensate to be washed away easily.

Abstract: A material for use as a gaseous diffusion electrode is provided. The material has improved durability resulting in long life. the material comprises a composite of a first layer of polytetrafluoroethylene (PTFE) containing a filler of a powdered electroconductive substance and a second layer of PTFE in bonded laminar contact with the first layer. The second layer preferably contains no electroconductive filler. The first and second layers are bonded together under pressure to form an intermediate composite and this intermediate composite is stretched, to produce the material of the invention which is a composite layered product of expanded PTFE having nodes interconnected by fibrils, one layer containing electroconductive material and the second layer preferably containing no electroconductive material. A catalytic substance can be incorporated onto or into at least the first layer by either deposition or by a filler of catalytic powder for use as the gas diffusing electrode of the invention.

Abstract: A composition of matter, and the method of making same, suitable for in vivo implantation to provide an environment in which normal tissue growth is fostered, which composition is a porous, fibrous structure of polytetrafluoroethylene fibers and resin, wherein the combination is sintered at a temperature which fuses the fibers together without substantial detriment to their tensile strength. The composition is prepared containing a material which is soluble in a suitable solvent, which subsequent to sintering of the composition, may be removed to produce the desired amount of void space in the composition.

Abstract: A method of preparing a tear-resistant composite sheet material having hydrophilic, absorptive particles enmeshed in a network of interlaced microfibrous polytetrafluoroethylene forming a fibril matrix, the hydrophilic absorptive particles having absorptive particles with absorptive capacity greater than 1.0 gram of water per gram of dry particle, wherein the method comprises:(1) dry blending one or more hydrophilic, absorptive particulate materials;(2) admixing water to particulate to form a damp mixture;(3) adding gradually, with stirring, to the mixture an equal weight of an aqueous emulsion of polytetrafluoroethylene;(4) mixing the mass to cause initial fibrillation of the polytetrafluoroethylene particles;(5) biaxially calendering the mass to produce a tear-resistant sheet having a tensile strength of at least 0.5 megapascal; and(6) drying the resultant sheet to remove water.

Abstract: A gas diffusion electrode for the reduction of oxygen, which contains a hydrophobic electro-catalyst layer, is described. One side of this layer is covered with a hydrophilic layer which is composed of at least one transition metal or an oxide or mixed oxide of transition metals and can also contain a current collector in the form of a mesh. For producing the gas diffusion electrode, a hydrophobic electro-catalyst layer can first be prepared from a pulverulent mixture which contains the electro-catalyst and a hydrophobic polymer, and at least one transition metal or an oxide or mixed oxide of transition metals can be applied in a finely divided form to one side of this layer and bonded to the hydrophobic electro-catalyst layer by the application of pressure.

Abstract: An improvement is provided for the manufacture of perhalogenated polymer, e.g., PTFE, bonded electrodes.The formulation comprises a mixture of an active material is carbon monofluoride (otherwise known as fluorinated graphite or fluorinated carbon or CF.sub.x or (C.sub.2 F).sub.n); a conductive carbon additive, such as acetylene black or graphite; and polytetrafluoroethylene (PTFE).The process comprises high shear mixing to cause the PTFE to fibrillate. The mixture is then wet with a non-polymeric pore-former to make the mixture more pliable and to create micropores in the electrode when the solution is removed by evaporation. The wet mixture is then sequentially suitably formed into a, e.g., extruded, or calendered or pressed to flatten the mixture to a thin sheet and rolled up and folded and pressed out again until a uniform sheet is obtained and the like.

Abstract: A method for extruding, stretching and sintering polytetrafluoroethylene in a single pass operation to form articles of low density sintered polytetrafluoroethylene and articles such as electric cable (C) having low density, sintered polytetrafluoroethylene insulation (F) applied about a conductor (W) by such method.

Abstract: A cleansing composition is disclosed that is particularly suited for compaction into tablet form, and comprises a phosphate salt, an improved perborate salt mixture wherein the improvement comprises a combination of anhydrous perborate and monohydrate perborate in the amount of about 50% to about 70% by weight of the total cleansing composition, wherein the combination includes at least 20% by weight of the total cleansing composition of anhydrous perborate, said combination having a portion present in a compacted granulated mixture with from about 0.01% to about 0.70% by weight of said combination of a polymeric fluorocarbon, said cleansing composition being capable of cleansing stained surfaces and the like with a soaking time of five minutes or less when dissolved in aqueous solution and producing a marked improvement in clarity of solution upon disintegration over the prior art.

Abstract: A shaped article having a synthetic resinous body and a thin fluoropolymer weld layer on its surface is formed by a process which comprises heating a heat conductive metallic core member, forming a thin fluoropolymer weld layer on the surface of the core member, treating the exposed surface of the fluoropolymer layer, forming a synthetic resinous body on the outer, treated surface of the fluoropolymer layer and removing the core member, such as by dissolving. In the shaped article thus produced, a thin fluoropolymer weld layer is formed on the surface of the synthetic resinous body, and the thickness of the fluoropolymer coating can be reduced. This permits the production of shaped articles at low cost and having high mechanical strength, even for complicated shapes. According to the invention, it is possible to produce articles having complex shapes such as corrosion resistant vessels, molds having good release characteristics, and so forth, at a comparatively low cost.

Abstract: A perfluorocarbon copolymer film which, upon heat shrinking, does not expand in the direction perpendicular to stretching.

Abstract: A process for producing a tube or rod of a polytetrafluoroethylene is described. The process comprises molding a polytetrafluoroethylene containing a liquid lubricant into a tube or rod by a paste process, removing the liquid lubricant, stretching the tube or rod in the lengthwise direction, and thereafter, by sintering the stretched tube or rod at a temperature of at least 327.degree. C. wherein the stretching of the tube or rod is carried out by the use of at least one pair of heating rolls which are each provided with a plurality of grooves. The process provided uniform stretching making it possible to produce a tube or rod with very small internal diameter.

Abstract: The invention provides an improved method for producing a filler-loaded thermoplastic resin composite by mixing a thermoplastic resin with a filler, making it possible to be applied to molding machine such as extrusion and injection molding machines without the disadvantage of segregation between the resin and the filler otherwise inevitable leading to inferior uniformity of the shaped articles. The invention is characterized by the presence of a fibrillatable polytetrafluoroethylene during the mixing under mechanical shearing forces, wherein the thermoplastic resin is melted in one case and not melted in other case. The invention is also effective for shaping cellular foamed bodies of a filler-loaded thermoplastic resin with fine and uniform cellular structure.

Abstract: A dimensionally stable asbestos diaphragm is formed by direct coating on the foraminous cathode of an electrolytic cell from an asbestos fiber-particulate polymer slurry, followed by fusion of the thermoplastic polymer.

Abstract: Porous polytetrafluoroethylene materials having high strength and coarse microstructure are produced by densifying the materials after removal of lubricant and then stretching. The term, "coarse," is used to indicate that the nodes are larger, the fibrils are longer, and the effective pore size is larger than conventional materials of the same matrix tensile strength. Densification can be achieved through the use of such devices as a densification die, a calender machine, or a press. This invention can be used to produce all kinds of shaped articles.

Abstract: The film (11) extruded from a vinylidene fluoride polymer is subjected to a stretching of at least 200% while still in the molten state, and then cooled rapidly to a temperature below 50.degree. C.The equipment comprises, in series, an extruding device (1) (2), a cooling device consisting of a thermostatically controlled liquid bath (6), the level of which is located at a distance of 10 to 300 mm from the extruding device, and a device (8) (9) for stretching the extruded film by at least 200% in its part located between the extruding device and the cooling device.The film obtained is suitable for manufacturing piezoelectric films.

Abstract: A method of manufacturing a porous tetrafluoroethylene tube comprises forming a sheet of tetrafluoroethylene containing a lubricant, winding it into a tubular shape, wrapping reinforcing material about the tubular shape to form a tubular product, rolling the tubular product so that it may have a uniform wall thickness, preheating the tubular product at a temperature lower than 327.degree. C., stretching the tubular product longitudinally, and heating it at a temperature higher than 327.degree. C., while holding it in its stretched position. The method may also be used to manufacture a tube containing 15 to 95% by weight of a filler.

Abstract: A method for producing a multi-component, porous PTFE article. Components of PTFE containing a liquid lubricant are placed in intimate contact, dried and then stretched in one or more directions. The PTFE components may optionally contain a filler. The resultant product has a virtually uninterrupted structure at the join and possesses very high bond strengths.

Abstract: This disclosure is directed to the preparation of a self-sustaining hydrophobic backing layer which also possesses excellent electrical conductivity so that it can serve as an intermediate layer between the current distributor and the active layer of a complete oxygen cathode. Said backing layer is formed by a simple process in which an intimate liquid dispersion containing finely divided carbon black and not more than equal parts by weight of PTFE particles ranging in size from about 0.05 to about 0.5 microns is dewatered and shaped into a thin layer which is thereafter lightly pressed and consolidated at elevated temperatures. Preferably, the carbon black is an acetylene black of a particle size range between 50 and 3000 Angstroms and the weight proportion of same is greater than the PTFE.

Abstract: A method for making polymer bonded electrode (PBE) structures wherein the particulate and particles of perfluorocarbon copolymer are combined with a solvent for the copolymer at a temperature where significant solvation of the perfluorocarbon does not occur. The resulting blended dispersion is spread to form the PBE, and the solvent removed. The PBE is then fused under heat and pressure for use.

Abstract: A composition comprising a chopped, bondable low friction yarn which is made by twisting together filaments of low friction material with filaments of bondable material and by impregnating the yarn with a bonding resin. A low friction bearing, and a process for manufacturing the same, involving the molding of bondable low friction yarn which has been chopped into small pieces, is also disclosed.

Abstract: A process for preparation of filler-containing polytetrafluoroethylene fine powder by coagulating polytetrafluoroethylene together with at least one filler selected from the group consisting of polyimide resins, polyamide-imide resins, polyamide resins and carbon fiber powders from their aqueous dispersion, characterized in that a water-insoluble organic liquid having a boiling point of from 30.degree. to 150.degree. C. and a surface tension of not more than 35 dyne/cm at 20.degree. C. is added to the aqueous dispersion under agitation at any stage from the start to the end of the coagulation.

Abstract: This invention provides a waterproof and breathable elastomeric polytetrafluoroethylene layered article for use in, for example, material for protective articles. The waterproof and breathable polytetrafluoroethylene layered article can for example, exhibit elastomeric properties of stretch to break of 275% in the machine direction, and 145% in the transverse direction and a total stretch recovery of at least 39% after being stretched to 75% extension for 100 cycles. This invention further provides a waterproof and breathable elastomeric polytetrafluoroethylene layered article bonded to a stretch fabric. The waterproof and breathable elastomeric polytetrafluoroethylene layered article bonded to a stretch fabric is thus durable and possesses a moisture vapor transmission rate exceeding 1000 gms/m.sup.2 day, and preferably above about 2000 gms/m.sup.2 day.

Abstract: Tetrafluoroethylene polymer tubes suitable for the preparation of lined pipe are prepared by ram extrusion wherein the tube is extruded above the sinter temperature and cooled below its crystalline melting point while radially unsupported to provide a tube of improved dimensional stability under thermal cycling.

Abstract: Tetrafluoroethylene polymer tubes are ram extruded. Desirable quality tubes are obtained by positioning an insert between ram and mandrel to maintain the ram and mandrel concentric.

Abstract: An extruder process for blending carbon fiber and tetrafluoroethylene copolymer resins, and laminates from the product of the process.

Abstract: A process for producing articles of polytetrafluoroethylene (PTFE) is disclosed. The process allows some of the conventional plastic fabrication techniques to be used with PTFE which until now have not been possible. The process comprises the steps of intensively mixing and thermokinetically heating PTFE resin in an enclosed container with a plurality of blades attached to arms rotating about an axis, with a blade tip speed of at least 30 meters/second, to a predetermined discharge temperature of above 370.degree. C., discharging the resin at the discharge temperature, forming the resin into a desired shape at a temperature at or below the discharge temperature, holding the resin in the desired shape above a predetermined forming temperature for a predetermined time, and cooling the resin in the desired shape.

Abstract: A composition suitable for manufacturing into wear-resistant and chemically-inert articles, the composition being a mixture of 74 to 84% polytetrafluoroethylene, 7-17% graphite fibers, and 4-14% fluorinated graphite.

Abstract: This disclosure is directed to strengthening carbon-black particulate "Teflon" (PTFE) mixes destined to be formed into active layers in air cathodes, which comprises mixing an aqueous dispersion of particulate polytetrafluoroethylene with an aqueous suspension of particulate carbon-black; washing and drying; mixing with a pore-forming agent; fibrillating said mixtures; washing and drying; adding polytetrafluoroethylene fibers while chopping said dried fibrillated mixture and thereafter forming said chopped mixture into a sheet, which was washed and dried.

Abstract: A flame retarded composition containing tetrahalophthalate plasticizer and a halogenated resin is provided.

Abstract: A piano action mechanism wherein a shaft pin for rotatably supporting a rotatable member on a flange is carried in bearings formed of bushing cloth glued to the surface of bushing holes in the rotatable member. With a pin inserted through the cylinders of bushing cloth, the assembly is dipped in water, dried, dipped in a solution of resin bonded fluorocarbon solids, again dried and the pin removed, to provide a durable and stable bearing having a low coefficient of friction and which is essentially noise-free and insensitive to changes in temperature and humidity.

Abstract: A method for producing a multi-component, porous PTFE article. Components of PTFE containing a liquid lubricant are placed in intimate contact, dried and then stretched in one or more directions. The PTFE components may optionally contain a filler. The resultant product has a virtually uninterrupted structure at the join and possesses very high bond strengths.

Abstract: The method of the present invention produces a porous, electrolyte permeable polytetrafluoroethylene diaphragm with a thickness of about 5 to about 100 mils and an average pore size of about 0.1 to about 100 microns. This diaphragm is suitable for use in an electrolytic diaphragm cell adapted to electrolytically form chlorine and an alkali metal hydroxide from an aqueous alkali chloride solution.

Abstract: Particle boards are currently prepared by treating the particles (e.g. wood chips) with a binder comprising an organic polyisocyanate and an internal release agent and then subjecting the treated particles to a forming process involving heat and pressure. While the resulting particle board will generally release well from the caul plates of the press after forming, due to the effect of the internal release agent, it has been found that the ease of release is enhanced by precoating the surfaces of the caul plates or platens which come into contact with the particle board with a layer of polytetrafluoroethylene which layer optionally contains an internal release agent.

Abstract: A fluorocarbon composite is provided for use as liners and particularly for use as wire insulation and in extruded tubing for push-pull cable assemblies. The composite has excellent anti-friction and abrasion-resistant properties and can be utilized in environments requiring operation over a wide range of temperatures and load conditions, including high temperature applications. The composition comprises a mixture of a polymer of tetrafluoroethylene and a polymer of arylene sulfide, which mixture may also include a filler.

Abstract: The present disclosure is directed to a process for treating gas electrodes containing a wetproofing (backing) layer which contains a polytetrafluoroethylene (PTFE) in conjunction with a water-soluble pore-forming agent and a PTFE-containing active layer to preserve and enhance their structural integrity which comprises contacting the electrode first with an alkylene polyol, or other water-soluble organic material having a plurality of hydroxyl groups, at temperatures ranging from about 50.degree. to about 100.degree. C. for a sufficient period of time to thoroughly wet the PTFE-containing active layer thereof, and thereafter contacting the thus-treated electrode with water in one or more washing steps to substantially remove the pore-forming agent. Between the hot soak with the alkylene polyol, or equivalent material, and the water wash(es), the electrode can optionally be dried.

Abstract: A method of connecting a plastic tube to a plastic hub is disclosed which includes preforming the tube by externally heating it in selected areas to cause outward bulging of the tube in those areas, applying an axial force on the tube to cause the bulges to compress axially while heated and molding the hub with the tube bulges in the mold.

Abstract: An improved preformed cathode is described for use in a primary electrochemical cell. The novel cathode of the present invention is a self-supporting member having a configuration which is determined by the spatial limitations of the particular primary electrochemical cell in which the cathode is to be utilized. The cathode is formed from about 65 to 94 weight percent of carbon black, at least 1 weight percent of a mechanical binder which is inert in the primary electrochemical cell, 1 to 10 weight percent of a fibrous material such as carbon, glass, ceramic fluoropolymer, and/or metallic fibers, and any remainder thereof is graphite powder. The preformed cathode is formed by mixing the individual components together with a quantity of a suitable liquid to form a uniform mixture which is sheeted to a self-supporting structure of the desired thickness.