Abstract: In a method of forming a hollow product in a molding apparatus having an upstream and a downsteam end a parison of thermoplastic material is extruded in a molten state from a heated extruder at the upstream end and moved through a product shaping region towards the downstream end of the apparatus. The material is cooled by passing a cooling medium internally of the product from the downstream end towards the upstream end of the apparatus.

Abstract: A narrow tape of high strength and low elongation to break for use for example as a tear tape or packaging tape is formed by extruding continuously from preferably polypropylene a strip of tape and applying to the strip an adhesive layer on one surface. After extrusion and after application of the adhesive strip, the tape is drawn longitudinally by an amount sufficient to substantially fully orient the tape in the longitudinal direction to provide the required low elongation to break and high strength. The tape is extruded in a width so that when drawn the width of the drawn tape is equal to the required width of the finished tape. Instead of slitting the tape from a wide web, therefore, the tape is extruded directly in tape width without slitting or trimming thus obviating any waste. In addition the longitudinal drawing of the tape reduces the thickness of the adhesive to a thickness just sufficient to provide the required level of pressure sensitive adhesion without use of excess materials.

Abstract: A method and apparatus for continuously extruding a product, and forming it into a bend by applying a force to it at a point of application downstream of where its surface becomes solid. The force has a transverse component relative to the die axis, and performs work upon the extruded material, extra to the work that has already been performed to extrude it. Non-contact members of applying the force are described, and various ram-type contacting members are illustrated. Alternative means of operation are described in which the point of application of the force to the extrudate during bending varies relative both to the extrudate and to the die, relative to the extrudate only, and relative to the die only. Means to alter the direction of bending are described, and to diminish the necessary bending force by creating a fluctuating melt pressure within the die.

Abstract: An apparatus is provided for extruding a polymer which is subject to periodic surges. The apparatus includes a barrel with an upstream portion for receiving polymer, a downstream portion and a discharge port near the downstream portion. The apparatus also includes a shaft mounted for rotational movement about a longitudinal axis within the barrel as well as drive means connected to rotate the shaft. The apparatus has a surge suppressor for urging polymer upstream toward the discharge port while permitting a portion of polymer to flow downstream into the surge suppressor. A sensor is positioned within the apparatus to detect surges in the polymer and a controller is connected to the sensor and to the drive means for adjusting shaft rotation in response to polymer surges.

Abstract: The invention relates to a hollow body made of fluoro resin, especially of PTFE, obtained by paste extrusion, exhibiting an anisotropy ratio lower than 1 and substantially equal to 0.5. For the manufacture of such hollow bodies a fluoro resin powder, especially unsintered PTFE, is mixed with lubricant, the mixture is compressed to obtain an isotropic compact tubular preform, the preform is introduced into an extrusion press, the preform is expelled through a passage of small cross-section of a die so as to form lengthwise-oriented fibers, the fibers are compressed at the exit of the passage in an internal expansion chamber of enlarged cross-section, so as to orient the fibers transversely, and the fibers are expelled through the exit orifice of the die to obtain a hollow body.

Abstract: A method and apparatus for extruding a multi-layer plastic pipe are provided wherein a second liquified plastic is injected into and through a prow and, subsequently, into a radial flow conduit of a die assembly in which a first liquified plastic flows through the radial flow conduit. Subsequently, the first and second liquified plastic are introduced into and through an annular flow conduit and a third liquified plastic is injected into the annular flow conduit of the die assembly. Wherein within the die assembly the first liquified plastic forms a first layer, the second liquified plastic forms a second layer inside the first layer and the third liquified plastic forms a third layer outside the first layer. Additionally, a multi-layered plastic pipe which can be produced by the inventive die assembly is provided. The multi-layered plastic pipe has an ultraviolet light-protective outer layer and a light-reflecting inner layer.

Abstract: A process for making a polyvinyl chloride and wood composite pellet by extrusion. The polyvinyl chloride and wood fiber are introduced into the extruder at a ratio of approximately 6:4 by weight, respectively. The polyvinyl chloride is melted and blended with the wood fiber so that the interstitial voids of the wood fiber are filled with polyvinyl chloride. After being extruded through a die, the molten material is cut into pellets having a bulk density of preferably between 0.7 to 0.8 gm/mm.sup.3.

Abstract: The present invention relates to a method for making a multilayer coextruded thermoplastic stretch wrap film useful for the packaging or pelletizing of goods. More particularly films made according to this invention include at least three layers: two outer layers and an intermediate layer positioned between the outer layers. The intermediate layer contains a mixture of a first linear low density polyethylene and a polyolefin selected for the group consisting of homopolymers of propylene, copolymers of propylene and ethylene and mixtures thereof. At least one of the two outer layers is a second polyethylene. The force required to stretch films made according to this method is controlled by varying the intermediate layer blend ratio between 85% polyethylene/15% propylene and 95% polyethylene/5% propylene.

Abstract: A process is provided for producing a plastic part that cannot be colonized by germs and/or fungi. The process includes the step of sequentially treating the plastic part with a swelling agent to provide a swollen plastic part, and then treating the swollen plastic part with a solution of a water-insoluble compound containing a bactericidal and/or fungicidal metal, where the solution has a bactericidally and/or fungicidally effective concentration of the insoluble compound.

Abstract: The present invention provides a novel process for preparing composites including layers having thermally distinct processing requirements. Beneficially, the process may use a single manifold die. By the process, useful containers may be manufactured.

Abstract: The present invention relates to a flexible tubular conduit with a jacket or tube made of crosslinked polyethylene, specially crosslinked polyethylene, and a method for manufacturing the conduit. A jacket or tube is made from polyethylene crosslinked by hydrolysis.

Abstract: The invention describes a process for cooling and if necessary calibrating elongated, especially continuously extruded objects (7) made of plastic as well as a cooling and calibrating device (5) for carrying out the process. With this the object (7) during its advancement in the longitudinal direction is exposed in consecutive regions (13 to 18; 86 to 89, 95 to 97) to a higher vacuum in each case and is cooled with respect to the initial temperature to a lower final temperature. The heat to be removed for cooling is extracted by a coolant washing round the object (7).

Abstract: A method for increasing the adhesion of a first layer comprising fluoroplastic to a second layer containing a peroxide-curable hydrocarbon elastomer is disclosed. The method involves adding a primary-amine containing unsaturated compound or polymer of less than 10,000 molecular weight to the hydrocarbon elastomer layer.

Abstract: Molten resin is extruded in a predetermined width from an extrusion nozzle. The molten resin is forced to a die wheel, which is situated facing the extrusion nozzle with a predetermined gap therewith, has inside a cooling unit and is adapted to be rotated in one direction. On the surface of the die wheel, a flat-plate-like substrate member and engaging members are integrally molded of the molten resin. Simultaneously, as a continuous filament is supplied, loop members are successively formed. Then the loop members are pressed against the substrate member in upright posture and are successively fused therewith.

Abstract: A method and apparatus for recycling previously used agricultural plastic film mulch in which the plastic film mulch is fed by a conveyor along a predetermined path of travel, while being agitated and shaken on the conveyor to dislodge and remove dirt and debris therefrom, shredding the plastic film mulch into discreet pieces in a shredder while removing additional dirt and debris therefrom, conveying the shredded plastic film mulch through a vertical separator along a second, tortuous path of travel, while drying the shredded plastic mulch by heated air and agitating the plastic film mulch by projections extending into the second path of travel to dislodge and remove still further dirt and debris therefrom, and extruding the cleaned and shredded plastic film mulch into a reusable form in an extruder, which melts the plastic film mulch, screens solids from the molten plastic, and extrudes the molten plastic into a reusable form, such as pellets.

Abstract: A process for the production of a plate with a polymer frame shaped onto the edge of the plate. The frame is extruded onto the plate while the latter is held stationary in a working station of a handling automaton or robot with a support device which corresponds to the shape of the plate in such a way that the edge of the plate projects freely over the support face of the support device. With the aid of the robot, an extrusion die having a through, mouth-like slot with two jaws engages the top and bottom surfaces of the circumferential edge of the plate as the mouth-like slot engages the plate edge. At the front end of the two jaws of the die mouth, there are sealing ledges movable at right angles to the plate surfaces, which are supported on the latter during the extrusion process.

Abstract: High molecular weight polyethylene products of high strength, good thermal resistance and creep resistance process in which the polyethylene is melt drawn in a multiple-stage drawing process in which the polyethylene extrudate is treated sequentially by a first drawing process which uses an elongating draw at an elongation strain rate of from about 0.03 to 0.5 S.sup.-1, a subsequent stage of elongating draw at a lower elongational strain rate, whilst subjecting the extruded polyethylene to UV crosslinking during the subsequent stage of elongating draw at lower elongational strain rate.

Abstract: An improved extrusion method is employed in a process which is used to form tubing for medical applications. The method includes providing an extrusion apparatus having a die which includes a die cavity and a mandrel within the die cavity. The die is rotated in a first rotational direction while the mandrel is rotated in a second rotational direction opposite the first direction. While the die and the mandrel are rotating, a PTFE paste is passed through the annular passage defined between the die and the mandrel. The die cavity is cooled to maintain the PTFE paste passing therethrough at a substantially non-elevated temperature.

Abstract: This invention relates in general to a method for the formation of films having a controlled molecular orientation prepared from rod-like extended chain aromatic-heterocyclic ordered polymers, and containing a binder in the micro-infrastructure. Such films have high tensile strength, modulus, and environmental resistance characteristics.

Abstract: A plasticizing method uses an apparatus (10) including a barrel (12) having a bore (14) therethrough. An auger (24) and a rotor (30) are positioned in the bore, each extending from opposed ends (16, 18) of the barrel (12) and having ends (26, 34) that are substantially flush. The auger (24) conveys particulate plastic material along the bore (14), the plastic being frictionally melted before passing the auger discharge end (26). The rotor (30) is provided to uniformly heat the melted plastic. Auger (24) and rotor (30) each are associated with independent means for rotating (28, 32) and means for controlling the speed of rotation (50, 52). The speed of rotation of the auger (24) controls the flow rate of plastic through the bore, and the speed of rotation of the rotor (30) controls the temperature of the melted plastic.