Abstract: Process and apparatus are disclosed for manufacturing foamed articles such as tubes used as pipe insulation, which tubes are of a high impermeability and flexibility and are formed of a polymer, such as polyethylene or polypropylene, containing up to about 25% of an elastomer.

Abstract: An expandable polymeric styrene particle is provided from which molded foamed articles can be produced exhibiting reduced flammability characteristics. The expandable polymeric styrene particle contains a blowing agent, a minor amount of pentaerythritol tetrastearate and a minor amount of hexabromocyclododecane. The additives can be incorporated during impregnation with the blowing agent or by blending with the expandable particles after impregnation.

Abstract: A process for alkylating aromatic substrates is disclosed which includes contacting the aromatic substrate with an alkylating agent in a reaction zone at temperatures of from about 350.degree. C. to about 500.degree. C. in the presence of a crystalline silica polymorph silicalite catalyst material.

Abstract: A process is disclosed for the formation of pipe comprising one or more layers of thermoplastic resin whereby an annular stream of thermoplastic material is transported through an annular extrusion passageway. The downstream annular portion of the extrusion passageway has a radially movable outer wall. The outer wall is radially moved by heat expansion of a bolt thereagainst to change the thickness of a particular arcuate section of the stream. The thickness of the particular arcuate section of the stream may be further changed through selectively heating by electrical resistive elements an arcuate section of the extrusion passageway to heat the stream of thermoplastic material transported in proximity thereto.

Abstract: Disclosed is a multiple heat exchanger system utilizing an inlet manifold to distribute the flow of thermoplastic material from an extruder to the inlet ends of each of the heat exchangers, and a discharge manifold to converge the flow of thermoplastic material from the discharge ends of each of the heat exchangers and to direct the flow to an extrusion die. The inlet and outlet manifolds include a main port in communication with a plurality of passageways within the manifold to allow flow between a main conduit in communication with the main port and a plurality of distribution conduits in communication with each of the heat exchangers. A flow control means positioned at each distribution port includes a sleeve, having a flow space therethrough, axially aligned within both the distribution port and distribution conduit. The distribution conduit includes a plurality of orifices about the circumference thereof in communication with the heat exchanger for the flow of thermoplastic material.

Abstract: An apparatus for the formation of a multiple layered pipe comprising a die housing having a bore therethrough with a mandrel longitudinally supported within the bore by a spider to provide an annular extrusion passageway defined by the inside surface of the housing and the outer surface of the mandrel. The mandrel comprises a series of sequentially positioned annular feed rings for the laydown of thermoplastic material on the inner surface of the main thermoplastic material flowing thereover through the extrusion passageway. The extrusion passageway is constricted downstream of the spider but prior to the annular sequentially positioned feed rings to reunite the thermoplastic material after the flow disruption created by the spider. Also included in the mandrel is a longitudinal passageway in communication with the inlet section of the bore for the transportation of thermoplastic material therethrough to one or more of the annular feed rings.

Abstract: A rotary extruder contains pump rings positioned at opposite ends of the rotor shaft to collect excess thermoplastic melt forced outwardly to the housing ends and to redirect this excess melt to the feed section of the extruder. Redirection of the melt is accomplished by helical grooves located on the inside surfaces of the pump rings having an axial component directed toward the center of the extruder to provide a conduit for the melt. The melt is also directed by a series of angular grooves positioned circumferentially about the rotor opposite the pump rings which rotationally and axially propel the melt as the extruder rotor rotates. The rotor shaft is supported by bearings at opposite ends of the shaft which are offset from the axial center of the bearing housing.

Abstract: A thermoplastic container bottom is inertially spin welded into the interior of a cylindrical container body of paperboard internally lined with a layer of thermoplastic material. A body supporting mandrel has an expansible body engaging portion which is inserted into the body and subsequently expanded to define a cylindrical surface of a diameter exactly equal to that of the specified internal diameter of the body. A seating member at the end of the body supporting mandrel establishes the depth to which the container bottom is inserted into the body and is provided with a low-friction projecting resilient member which contacts the rotating bottom.