Abstract: Disclosed is a method of preparing an asbestos diaphragm containing a thermoplastic resin. According to the method disclosed herein, an asbestos mat is prepared by drawing the asbestos mat from a salt free, aqueous, asbestos slurry, providing the resin, and thereafter heating the mat to form the resin reinforced mat.

Abstract: An improved method for the production of an extrudate of poly(phenylene sulfide) and filler with the resulting extrudate having a stiffness of less than 10,000 psi as determined by ASTM D747-70. The extrudate formed is very flexible. The method includes the step of applying pressure to a heated mixture of poly(phenylene sulfide) and filler and flowing the mixture through a first orifice into an expansion chamber and out of the expansion chamber through a second orifice. The extrudate exiting the second orifice is extruded into the atmosphere or into a mold cavity for the molding of a piece part. The resulting extrudate is flexible and can be used as a packing or gasket material.

Abstract: An electrical resistor is manufactured by molding a mixture of the powders of tetrafluoropolyethylene, carbon and metal and then sintering the molded body. Terminals comprising a mixture of a powder of tetrafluoropolyethylene and a powder of soft metal are provided by simultaneously molding a lamination of the first mentioned mixture and the second mentioned mixture.

Abstract: A porous film of polytetrafluoroethylene having an accurately controlled pore diameter and a superior pore diameter distribution, and a process for preparing the film.

Abstract: Disclosed are gasket and seal materials comprising particulate material interconnected and entrapped by fibrillated polytetrafluoroethylene and methods for manufacturing and using them.

Abstract: Fluoroelastomers, including ultra high temperature, thermally stable fluoroelastomers, are bonded to a metal backing member by (a) compounding the fluoroelastomers with CaO, (b) curing the fluoroelastomers in contact with a pretreated surface of the metal member, and (c) postcuring the fluoroelastomers/metal unit at elevated temperatures.

Abstract: A novel cloth comprising asbestos fibers, particularly in the form of a micro-porous membrane is provided and a method of obtaining this cloth. It is characterized in that said cloth is obtained by the dry mixing of asbestos fibers and at least one filler or charge substance, then working up by malaxation in the presence of a latex, forming the cloth and, optionally, elimination of the filler substance. The invention is particularly applicable in the production of a micro-porous membrane for use in electrolysis diaphragms.

Abstract: An improved felt-like material made from filamentary polytetrafluoroethylene (PTFE) is provided. The improvement is the presence of fibrils of PTFE criss-crossing interstices of the felt. These improved felt-like materials have a higher air porosity, while maintaining as high a filtering efficiency, than the currently-used felt-like materials.

Abstract: A plug valve whose chamber or bore and whose runs or port passages are fully lined with corrosion-resistant material, most preferably polytetrafluoroethylene, such valve having recesses in its runs, near their intersection with the bore, into which lining material distended by heat and pressure may creep, and with the valve body defining an internally-rounded concave wall or dome at the bottom of the bore. The lining material is formed within the runs so as to be under tension longitudinally between the bore and the outer ends of the runs, and the lining material extends integrally upwardly from the bore and outwardly of the valve body to define a thick collar immediately above the neck of the bore. The valve is manufactured by use of an integral hollow rubber or like forming element comprised of tubular legs, and is placed inside the valve body with one such tubular leg extending through each run and through the bore.

Abstract: A method of obtaining a micro-porous membrane is provided as well as the improved membrane. Said method is characterized in that a homogeneous paste is prepared from a pore-forming filler substance and a latex, and said paste, which is reduced to powder form, is dried and a membrane is formed therefrom and then (fritted) sintered, and the pore-forming filler substance is then removed. The membrane thus obtained is particularly useful as a diaphragm for electrolysis cells.

Abstract: Finely divided granular polytetrafluoroethylene powders are agglomerated by mechanically agitating them while the PTFE is wetted with an aqueous solution containing a protective colloid.

Abstract: A uniform, porous, homogeneous diaphragm for use in electrolysis cells is provided by bringing together a homogeneous, stable suspension of asbestos fibers in water and a fluorinated polymeric resin latex with a pore-forming agent in the presence of a sulfonated anionic surfactant, the resulting suspension being shaped to the desired form of the diaphragm by filtration, the desired shape of the diaphragm then being dried and sintered at a temperature above the crystalline melting point of the fluorinated polymeric resin, the pore-forming agent finally being removed from the resulting diaphragm by decomposition or extraction.

Abstract: Polytetrafluoroethylene bags used in solids filtering units are preshrunk to preclude tearing or ripping of the bags.

Abstract: A process for free sintering parts made from mixtures of poly(phenylene sulfide) and at least one selected filler by subjecting molded parts to gradually increasing temperatures and then curing at an elevated temperature. Precured poly(phenylene sulfide) is first mixed with the selected filler and then compression molded to form a part of a desired shape. The part is then free sintered by being subjected to a gradually increasing temperature in an oven and cured. After curing, the part is cooled and is ready for use.

Abstract: An improved hydrophobic polymer matrix having preselected wettable characteristics.