Abstract: A porous polytetrafluoroethylene (PTFE) article which is made up of a number of smaller articles with a microstructure of nodes interconnected by fibrils, these articles having been joined to one another such that their microstructure is virtually unaltered across the join. A process for producing such a PTFE article by closely abutting small-shaped PTFE segments and applying a force perpendicular to the seam while heating to a temperature above the crystalline melt point of the segments.

Abstract: Tubing of a thermoplastic polymer for handling corrosive materials is laminated or reinforced by covering the same with a heat-softenable bonding agent as an adhesive, inserting the adhesive-covered tube in a cylindrical glass fabric sleeve, inserting the assembly in a hollow cylinder, heating the tube to a temperature to cause the softening of the bonding agent and adhesion to the tube, forcing the tube with air or centrifugal force against the inside of the cylinder to force softened bonding agent into the interstices of the glass fabric, and cooling the entire assembly while expanded to adhere the bonding agent to the fabric and thereby form a unitary structure. The reinforced tube can be bonded to the inside of a preformed steel or fiberglass-reinforced plastic pipe to serve as a protective liner therefor.

Abstract: The present invention provides a process for treating polyvinyl fluoride surfaces to enhance adhesion of other polymers thereto comprising applying to at least one surface thereof a solution consisting essentially of a coating polymer selected from a polyurethane or an alkyl polymethacrylate and at least one aprotic polar solvent in which said polymer is soluble, and exposing said surface to a temperature of from about 120.degree. C. to 230.degree. C. for a time sufficient to evaporate said solvent. The treated polyvinyl fluoride having an adhering intermediary surface of polyurethane or alkyl polymethacrylate usefully serves as a means to secure the polyvinyl fluoride to another polymer which otherwise would not adhere to polyvinyl.

Abstract: An improvement in a process for preparing a laminate consisting of a fluorocarbon copolymer sheet of 5 or more mill thickness and a fabric is disclosed. The improvement is using a thin sheet of a fluorocarbon copolymer having a specific melt viscosity low enough to enable the copolymer to wet and penetrate the fabric at fabrication temperatures as an interlayer between the fabric and thick fluorocarbon copolymer sheet and then integrally bonding the laminate by means of heat and pressure. The use of the interlayer increases the level of adhesion between the thick sheet and the fabric.

Abstract: Sheets, strips or filaments of thermoplastic resin are produced by one or more extruders working into a remote shaping die that is movably juxtaposed with a cooling drum around which the hot product issuing from the die mouth is to be wound, the die being connected with the extruder or extruders via one or more flexible ducts having heating elements embedded in their walls. Each duct may comprise an inner hose of Teflon, an outer envelope of reinforced silicone rubber and various intermediate layers including a heating layer in the form of a wire coil or mesh and a surrounding heat barrier of asbestos.

Abstract: An evaporator adapted to convert a liquified gas, such as chlorine, into a gas, the evaporator including an enclosed vapor chamber functioning as a pressure vessel. The vapor chamber is suspended within a water chamber having a heater serving to raise the temperature of the water to a level at which heat transfer through the wall of the vapor chamber causes the liquified gas fed therein through an inlet pipe to evaporate and produce a superheated gas that is discharged through an outlet pipe. The vapor chamber is fabricated of a steel tank whose outer surface is coated with a film of tetrafluoroethylene having a thickness just sufficient to render the film impermeable to water, thereby inhibiting corrosion of the steel surface and the formation of scale thereon, the thickness of the film being insufficient to materially reduce the heat transfer characteristics of the vapor chamber.

Abstract: A method and apparatus are disclosed for producing a composite pipe for handling destructive materials under pressure and vacuum conditions. The pipe includes a tubular liner formed of thermoplastic material capable of withstanding the destructive material. A strip of glass fiber fabric is helically wrapped around the outer surface of the liner. Heat is applied externally to the wrapped liner at a sufficient rate to simultaneously melt the exterior surface of the liner and thermally expand the liner radially outwardly into the openings in the fabric. Upon cooling, a permanent mechanical bond is achieved between the liner and the fabric. A layer of fiber glass and resin is then applied to the outer surface of the wrapped liner for structional rigidity and strength.