Abstract: Composite polymeric articles, which may be in layer or film form, comprise a larger portion of a polymer which is water soluble at 20.degree. C. against a smaller proportion of a polymer which is substantially water-insoluble at that temperature. For example, a layer product may have a thin layer (e.g. less than 5 microns) of insoluble polymer superimposed on a thicker layer (e.g. at least 20 microns) of soluble polymer. Both polymers are conveniently polyvinyl alcohol, which is non-toxic and useful in a number of domestic applications, e.g. as a diaper backing sheet. The insoluble portion gives water resistance but negligible mechanical strength; the soluble part gives the mechanical strength. On dissolution of the soluble portion, the insoluble portion disintegrates mechanically. Articles may be made by co-extrusion or by molding.

Abstract: An instrument panel top cover with a seamless breakaway air bag door made as a unitary composite from multiple layers of plastics by extruding a parison with inner and outer layers of different recyclable plastics having different physical characteristics but which are from the same plastics family. The parison is injected and expanded with low pressure gas and forming dies with door scoring tools are closed thereover. The plastics will resultantly conform to the shaping surfaces of the dies to form the composite while the perimeter of the air bag door is scored. A quantity of the plastic material interior of the door score lines is removed after the top cover is removed from the dies so that a seamless or hidden door is provided that can readily break open at the peripheral scores to augment air bag operation when the air bag is triggered.

Abstract: A plastic bottle having at least an outer face formed of an olefin-base resin, wherein the olefin-base resin has a density and a melt tension satisfying the following formula (1):Y<-AX+B (1)wherein Y is the density (g/cm.sup.3) of the olefin-base resin, X is the melt tension (g) of the olefin-base resin, A is a constant having a value of 0.0116 and B is a constant having a value of 0.962,and the bottle outer face has a glossiness of 60% (60.degree. gloss) or more. Also disclosed is a process for making the above-described plastic bottle.

Abstract: A rod 3 is driven forward to open an annular slit 5 between a die 2 and a mandrel 4 and the molten resin in a resin accumulation chamber 10 is expelled from annular slit 5 to form a parison. In this operation, the die 2 is displaced from an original position adjoining to the mandrel 4 (axially aligned position) upon opening of the annular slit 5 to correct for any variation in thickness of parison P to be extruded from the annular slit 5. Then, the molten resin accumulated in accumulation chamber 10 is expelled from annular slit 5 to form parison P. The die 2 is then reset to the original position to bring the die 2 and mandrel 4 into axial alignment. Therefore, as the rod 3 is driven back, the annular slit 5 can be closed tight by the mandrel 4 to prevent resin leakage. After closure of the annular slit 5, molten resin is accumulated again in the accumulation chamber 10 and the annular slit 5 is opened. This procedure is repeated to produce parisons on an intermittent basis.

Abstract: A sports ball bladder and method of manufacture which produces a sports ball in which a valve element (48) is fused to the bladder and is disposed away from a parting line (40) of a mold (34). The bladder is made by extruding a parison (64) and closing a mold cavity (42) in surrounding relation thereof. A blow needle (46) supports the valve element thereon and delivers fluid pressure to an interior area (68) of the parison. The expanding parison fills the mold cavity and impinges on the valve element. The expanded parison is cooled to solidify the thermoplastic material. The pressure in the interior area is then relieved through the blow needle and the mold is opened. To avoid thinning of the bladder adjacent to the parting line, thermoplastic material is pushed inwardly into the mold cavity from a pinch pocket (80) as the mold is closed. After the ball bladder is formed, a valve member (72) is inserted into the valve element to enable holding of the bladder in an inflated condition.

Abstract: A polymer resin extrusion head includes one or more annular extrusion modules in which a spiral channel means having one or more convolutions extends from a resin inlet on the periphery of the module to an annular extrusion outlet. Preferably, the channel means gradually opens into an annular frustoconical space leading to the extreusion outlet at the inner edge of the module. The spiral channel extends symmetrically around the extrusion module or modules in a manner so as to subject all of the extruded polymer flowing from the inlet to the extrusion outlet to substantially the same process conditions along the flow path. As a result, the polymer is distributed at the outlet with properties which are substantially symmetrical around the axis of the extrusion module or modules for all resin distributed to the outlet.

Abstract: A composite camel structure includes an elongate hollow, rigid cylindrical core, opposite ends of the core having respective caps sealingly connected thereto, a buoyant material of cured urethane foam substantially filling the core and being sealingly enclosed therein. A cushion is thermally bonded to and sealingly surrounds the core, the cushion having a substantially unbroken outside surface, being formed of a polymeric component consisting of polyethylene being at least 80 percent low-density polyethylene, and a process additive component including an effective amount of an ultraviolet inhibitor. A pair of parallel-spaced, transversely oriented guides extend between opposite sides of the cushion in axially spaced relation to the core, each guide defining a guide opening through the cushion for receiving hawser chains whereby the camel structure rides up and down with the tide.

Abstract: A process for producing a muffler hose having opposite ends, an intermediate portion having a noise-reducing communication hole, and a noise-reducing expansion chamber. The process includes the steps of fitting a protector at the opposite ends of the hose, and disposing the hose and the protectors in a separable blow-molding mold having a jaw; extruding a tubular parison around the hose and the protectors, closing the blow-molding mold, reducing the parison diametrically at two axially-apart positions by the jaw, clamping the parison around the hose at two axially-opposite positions of the hose, the two axially-opposite positions being intervened by the communication hole, and placing the opposite ends of the parison around the protectors; and blowing air into the parison through one of the protectors, and the communication hole of the hose to expand the parison, thereby forming the expansion chamber.

Abstract: A cover unit is constituted such that a conductive member is provided on the entirety of the inner wall of a hollow cover, and the periphery of the conductive member is fixed to the cover.

Abstract: A method and apparatus for blow molding articles having a circumferential sidewall terminating in a closed top in which at least one preformed solid hoop is partially fused to the circumferential wall of the article and projecting axially above at least a portion of said top end. The entire outer peripheral edge portion of each reinforcing hoop is concentrically placed underneath the extrusion head with a suitable fitting. Thereafter, a tube of soft thermoplastic material is extruded through the totally open central portion of the hoops until the end of the tube overlies the pneumatic nozzles. Each mold half consists of a center sections and intermediate sections that are relatively movable in a direction lengthwise of the mold to enable both engaging the hoops and loosening the blow molded article of the mold. End mold sections slide on an incline to fully close the mold. The semi-cylindrical mold central halves close to radially position the hoops and form a cylindrical mold.

Abstract: An at least 4-layer co-extruded, biaxially stretched, tubular seamless casing for sausages to be heated in water and cooking-sausages, having improved tearing properties in the filled state associated with a decreased tendency to burst open when the sausage product is first cut, containing at least two layers composed predominantly of aliphatic polyamide, which form the inner and outer surfaces of the tube, and at least two additional layers, which are enclosed by the inner and outer polyamide layers, with at least one of the enclosed layers acting as a water vapor barrier and having the structure of a polyolefin and at least one other of the enclosed layers acting as an oxygen barrier and consisting mainly of ethylene vinyl alcohol copolymers, the quotient of the tear resistance in the transverse direction to the tear resistance in the longitudinal direction lying between about 0.65 and 0.85, with the degree of surface stretching of the film product being between 8 and 11.

Abstract: An apparatus for forming a thermoplastic pipe having a profiled surface includes a nozzle having an extrusion orifice feeding extrudate in a downstream direction to a mold path which extends from the nozzle and along which are provided a first mold block and a second mold block downstream of the first mold block. The mold blocks are closable around the extrudate to form the pipe and are openable to release the pipe. The mold blocks are moved together with one another and with the pipe in the downstream direction when the mold blocks are closed and are opened and sequentially moved in an upstream direction along an axis contiguous with the axis of the mold path while the extrudate continues to move in the downstream direction. The first mold block is moved in the upstream direction before the second mold block such that the mold blocks never pass one another on the mold path.

Abstract: A squeezable tubular container (a) which is formed from a composition containing a polyethylene having a density of 0.900 to 0.975 g/cm.sup.3 and an ethylene/.alpha.-olefin copolymer having a density smaller than 0.900 g/cm.sup.3, (b) has a crosslinking caused under irradiation with electron beam, and (c) is sterilizable at a high temperature or is heat-sealable or ultrasonically sealable; and a process for the production thereof.

Abstract: An apparatus for manufacturing multilayer hollow articles having sections different from one another in respect to the kinds of resins, number of layers, and thickness of layers along the circumference in the horizontal section of an article with the narrowest of the sections in any one of the resin layers extending in a specified width along the longitudinal wall of an article and being capable of satisfying the sectional performance requirements. An apparatus is provided for manufacturing multilayer hollow articles with the wall thickness ratio of resin layers in each section varying along the longitudinal wall of an article or those with the sectional width in each resin layer varying along the longitudinal wall of an article. Hollow articles molded by the apparatus of this invention are particularly useful for automotive bumpers, the seats and backs of chairs, and boiler-room doors.

Abstract: Provided is a blow-molded article which can be readily formed with good Gloss and with substantially no surface unevenness, even without application of surface coating, and which can be used as a finished product without further treatment. The blow-molded article has a base layer and a surface layer. The base layer is formed from a thermoplastic resin material having a melt index (MI) of about 0.05-2.0 and a flexural modulus of 1,470 MPa (15,000 kgf/cm.sup.2) or more. The surface layer is formed from a colored or transparent thermoplastic resin material having an MI of about 1-30 provided that it is higher than that of the base layer, and excellent weather resistance. The thermoplastic resins used to form the base and surface layers should be resins of the same family.

Abstract: In the manufacture of composite paperboard/polymer packages, the adhesion between the polymer component and paperboard component can be enhanced by treating the polymer film with a surface treatment, for example, ozone, before the two components are brought together. The present invention is particularly applicable to a blow molding process employing one or more paperboard blanks and a blow molded polymer film.

Abstract: An extrusion molding apparatus includes a die head with first, second, third and fourth annular nozzles. An adhesive extruder is connected to the first and third nozzles, a barrier extruder is connected to the second nozzle and a reclaimed material extruder is connected to the fourth nozzle. Inner and outer main material flow passages are connected to a main material extruder, as well. The annular nozzles and the main material flow passages are connected to an extrusion nozzle for forming a parison. The barrier material extruder has a cylinder which is connected to the second nozzle. A screw lies within the cylinder. The second nozzle has a ridge opposite an end of the screw, for dividing the extruded barrier flow material, mitigating stagnation of the barrier material as it passes through the second nozzle. A method of forming a parison is described, as well.

Abstract: An energy absorbing interior automotive trim part (36) has a shell (42) made from polypropylene sections (62), (68), and (69) divided via partitions (58) and (72) extending from the outer wall (44) of shell (42) and touching the passenger compartment facing wall (46). The shell (42) is blow molded with carpet (74), vinyls and other fabric materials (76) integrally molded to adhere directly to wall (46). After molding, interior section or partial section (62) is filled with a structurally engineered energy absorbing foam (64) to provide an energy absorbing structure which will compress a pre-determined distance while absorbing the compressive force applied.

Abstract: A container incorporating post-consumer recycled ("PCR") plastic and a method of making that type of container. The container utilizes a layer of polypropylene or EVOH or a film of fluorinated polyethylene toward the interior from the recycled plastic to prevent contaminants from the latter entering the container's contents. When utilizing EVOH, the container usually has an additional layer of polyethylene or polypropylene covering the EVOH to prevent its deterioration by moisture. Making the container involves first composing a resin including the recycled plastic. Forming the various layers listed above produces a container that includes recycled plastic and a barrier to limit the migration of contaminants from the recycled material to the container's contents. This permits the use of the resulting containers for food. For a fluorinated polyethylene film, fluorination can occur either during or after the container's formation.

Abstract: A process for producing a hollow or sheet molded product having a superior appearance is provided, which process is characterized in that a multi-layer molded product having a surface layer (A) of a propylene random polymer of m.p. of 100.degree. to 150.degree. C. having a thickness of 1 to 20% of that of the molded product, and a substrate layer (B) of a thermoplastic resin of a m.p. higher than that of the propylene random polymer is formed and the surface layer (A) is heat-treated into a molten state, followed by immediately cooling to form a smooth surface.

Abstract: A preform mold assembly for the injection molding of a multi-layer preform for use in the blow molding of container. The preform mold assembly comprises a preform mold having a gate for receiving molten plastic material. The preform mold has a cavity with longitudinal axis and defines an inner surface. A core-pin is situated within the cavity and spaced from said inner surface. A preform cavity is formed between the inner surface of the cavity and the core-pin for receiving molten plastic from the gate. A threadsplit portion is situated within the cavity at a location remote from said gate. The inner surface of the cavity defines a plurality of flutes formed generally parallel to the cavity longitudinal axis and extend longitudinally along the inner surface of the mold to the threadsplit portion.

Abstract: A multi-layer preform for forming multi-layer containers includes an extruded inner barrier layer containing polyethylene naphthalate, said inner layer having an upper portion adapted to be formed into an upper portion of a container, an intermediate portion adapted to be formed into an intermediate portion of a container, an extruded and a base portion adapted to form a base portion of a container. The preform includes an outer injection molded layer. The inner layer has a thickness which differs from the base portion to the upper portion.

Abstract: A composite legal type bicycle frame is disclosed which contains a front frame portion and a rear frame portion. The front frame portion contains a central main and a plurality of legs for connecting the central main with various components of the bicycle, and the rear frame portion contains a rear fork, which consists of a left rear branch and a right rear branch. The left and right rear branches are first cured and glued together at respective abutting surfaces thereof to form an integral rear fork before they are adjoined with the front frame portion, via prepregs and using a cocuring procedure. The left and right rear branches are formed to contain cross-shaped matching protrusion and recess, respectively, on the abutting surfaces thereof, so as to enhance the integrity of the integral rear fork. As a result, a great flexibility of design options can be obtained. For example, the rear fork can be connected to one of the legs but not to the central main.

Abstract: A die head for extruding an annular body includes a mandrel having a warp portion with a number of segments spaced around the circumference of the mandrel. Heat is selectively flowed to the segments to warp the mandrel and vary the position of a die pin on the end of the mandrel in a die bushing to control the thickness of the extruded body.

Abstract: This invention provides a blow molding process for manufacturing multilayer hollow articles having sections different from one another in respect to the kind of resins, number of layers, and thickness of layers along the circumference in the horizontal section of an article with the narrowest of the sections in any one of the resin layers extending in a specified width along the longitudinal wall of an article and being capable of satisfying the sectional performance requirements, an apparatus, and said hollow articles. It also provides a process for manufacturing multilayer hollow articles with the wall thickness ratio of resin layers in each section varying along the longitudinal wall of an article or those with the sectional width in each resin layer varying along the longitudinal wall of an article, an apparatus, and said hollow articles.

Abstract: A balloon catheter comprises a flexible, elongated member, an inflatable balloon carried on the elongated member to define an inflated chamber within the balloon, and an inflation conduit extending along the member and communicating with the inflation chamber. The inflatable balloon, in turn, defines a wall which comprises at least three bonded layers. A first pair of the layers comprises a flexible plastic material which is typically a condensation polymer. A second of the layers comprises a flexible polymer which is typically a vinylic polymer which is covalently bonded to the first layers and positioned between them.

Abstract: A hollow plastic container having a finish which has a diameter less than the diameter of the body portion of the container which is made by forming a parison with a neck portion for defining the finish and a body portion and thereafter expanding the body portion to a cross section greater than the cross section of the neck portion. The neck is then trimmed by removing plastic material from the outside of the neck and from the top of the neck to form the finish to the final dimensions. In one form, the prison is a multi-layer parison in order to form a multi-layer plastic container.

Abstract: A non-coextrusion process for making multi-layer angioplasty balloons involves pre-forming separate parisons and then concentrically disposing the plural parisons to form a composite parison which is then subjected to a blow-molding process. The resulting balloon can have its properties tailored by appropriate selection of the particular plastics to be used for the multiple parisons.

Abstract: A method of attaching a clip to a tubular blow molded article and the clip, the method comprising the steps of: preparing a clip including a clip body and a clip base which is provided at a base portion of the clip body and has a hollow and a number of through-holes communicating with the hollow; inserting the clip body of the clip into a cavity formed on a molding surface of the mold such that the clip base projects from the molding surface; setting softened synthetic resin to the mold; and bringing the synthetic resin into close contact with the molding surface of the mold at a blow pressure so as to deliver the synthetic resin to the hollow and the through-holes of the clip base such that the synthetic resin is filled into the hollow and the through-holes of the clip base, whereby the synthetic resin is molded to the blow molded article having the clip projecting from its outer peripheral surface.

Abstract: In a multilayer bottle having at least two layers including an outer layer and an inner layer according to the present invention, the inner layer and the outer layer adjacent thereto are separable from each other at a body of the bottle while the inner layer and the outer layer are adhered to each other at least a part thereof in order to prevent the deformation of the bottle due to the reduction of a pressure in the bottle. When the pressure in the bottle reduces due to the volatilization of a content in the bottle or due to the discharge of the content by a pump and the like, the inner layer is separated from the outer layer and is crushed in the form of a bag, so that the outer layer is not deformed at all.

Abstract: A squeezable tubular container (a) which is formed from a composition containing a polyethylene having a density of 0.900 to 0.975 g/cm.sup.3 and an ethylene/.alpha.-olefin copolymer having a density smaller than 0.900 g/cm.sup.3, (b) has a crosslinking caused under irradiation with electron beam, and (c) is sterilizable at a high temperature or is heat-sealable or ultrasonically sealable; and a process for the production thereof.

Abstract: A coextruded multilayer film having increased retention of volatile antioxidants and process for making the film. The multilayer film includes an antioxidant layer containing a volatile antioxidant, said antioxidant layer being semipermeable to the volatile antioxidant; and a barrier layer, impermeable to the volatile antioxidant. The film can be produced on a conventional blown film process with the barrier layer coextruded externally to the antioxidant layer. The barrier layer traps the volatile antioxidant inside the tube of the blown film process, reducing the amount of volatile antioxidant migrating from the film.

Abstract: In a process for the production of a hollow body of thermoplastic material which is to include an additional portion, by expansion of a preform in a blow molding mold, the additional portion is connected to the hollow body upon expansion of the preform to form the hollow body. To form the connection between the hollow body and the additional portion, the latter is heated by a heating element which is brought into contact with at least the surface of the additional portion that is to involve the welded connection to the hollow body, prior to expansion of the preform. The heating element is brought into contact with the additional portion when already disposed in the blow molding mold in order in that way to heat at least the appropriate surface of the additional portion to a temperature which premotes the production of an adhesive join to the hollow body. The region of the additional portion that is to be heated is at least substantially covered relative to the outside atmosphere by the heating element.

Abstract: A composite molded wheel assembly and method of construction wherein a separately formed injection molded tread is flow melt bonded to a blow molded rim. The tread may comprise multiple tread pieces which are spaced over a tread surface. Bond enhancing grooves and/or projections may be provided on inner surfaces of the tread pieces and/or rim. The tread pieces flow melt bond to the rim during the molding of the rim. The rim includes an axle bore containing hub, a tread support wheel box and a plurality of connecting spokes and intervening web pieces. The method includes the steps of preparing and retaining the tread within the rim forming mold, introducing a parison of rim material having a melt temperature greater than the tread material, injecting pressurized air or gas to conform the rim material to the mold and tread pieces and controlling the molding cycle temperature, pressure and time parameters to promote bonding.

Abstract: A method for making a fuel tank containing an internal gas removal system by introducing a breathing and/or a venting system into a blow mold for a fuel tank and subsequently blow-molding the fuel tank around these systems.

Abstract: An easy open tear control package, preferably a pouch, from a film of polymeric barrier material is disclosed. Methods and films for making of such packages are also disclosed. The easy open tear control feature arises from roughening portions of the outer or inner surface of the films, prior to fabricating into the package. The roughened portion is on one face or on each face of the package and is at least a full width of a seal when the film is made into the package. The roughened portion can extend the entire width of the package and can be of any desired length.

Abstract: A method of manufacturing a wire harness protector (2), which can reduce the manufacturing cost with excellent productivity. A resin material is employed to form a hollow compact (1) by numerically controlled (NC) blow molding. Then, the as-formed hollow compact (1) is cut with a laser beam to remove unnecessary portions, thereby manufacturing a solid wire harness protector (2).

Abstract: A machine for making plastic tubing including a plurality of separate carriages for carrying mold blocks about the continuous path. A mold train drive engages a selected number of carriages at the beginning of the mold tunnel to continuously drive the carriages along the mold tunnel. A shuttle drive follows the continuous path through a shuttle area and spaced from the path along a substantial portion of the mold tunnel, and includes first and second carriage engaging sections at substantially opposite points along the drive so that a carriage at the end of the mold tunnel becomes engaged by one shuttle drive engaging section while the other shuttle drive engaging section engages a carriage at the beginning of the mold tunnel.

Abstract: For the continuous manufacture of a compound pipe with a spigot which is substantially smooth on its outside, the compound pipe including a smooth internal tube and an external tube provided with transverse grooves and welded together with the internal tube, an external tube and an internal tube are extruded, the latter into the external tube. While the spigot which is substantially smooth on the outside is manufactured, its external wall is pressure-relieved by compensation chambers.

Abstract: This invention provides a blow molding process for manufacturing multilayer hollow articles having sections different from one another in respect to the kind of resins, number of layers, and thickness of layers along the circumference in the horizontal section of an article with the narrowest of the sections in any one of the resin layers extending in a specified width along the longitudinal wall of an article and being capable of satisfying the sectional performance requirements, an apparatus, and said hollow articles. It also provides a process for manufacturing multilayer hollow articles with the wall thickness ratio of resin layers in each section varying along the longitudinal wall of an article or those with the sectional width in each resin layer varying along the longitudinal wall of an article, an apparatus, and said hollow articles.

Abstract: A process for producing a hollow or sheet molded product having a superior appearance is provided, which process is characterized in that a multi-layer molded product having a surface layer (A) of a propylene random polymer of m.p. of 100.degree. to 150.degree. C. having a thickness of 1 to 20% of that of the molded product, and a substrate layer (B) of a thermoplastic resin of a m.p. higher than that of the propylene random polymer is formed and the surface layer (A) is heat-treated into a molten state, followed by immediately cooling to form a smooth surface.

Abstract: An appliance door particularly suited for use as a refrigerator or freezer door includes a hollow, blow molded door slab, and a food storage shell or casing projecting from one wall of the slab. The parts forming the shell are prepared in a first step, e.g., by blow molding, and then are removably mounted as inserts in registering recesses formed in the bottom of the cavity of one of two plates or sections forming the mold for the door slab. The two mold sections are then closed over a tubular, plastic parison which is then inflated to form in the mold the hollow door slab, portions of one wall of which mold over and around a series of male projections which extend into the mold cavity from the mold inserts, thus causing the shell to be molded to and to project from the slab upon subsequent opening of the mold sections and removal of the slab therefrom.

Abstract: Disclosed is an elastic film having improved properties. The elastic film can be blown, cast or cast embossed. The elastic film is processed by polymerizing olefins in the presence of a metallocene catalyst system.

Abstract: The bottle-shaped container is made in a coextrusion blow molding process and has a dimensionally stable outer container and an easily deformable inner bag which consist of different thermoplastic materials that cannot be welded to each other. The preform has a diameter greater than that of the bottle neck so that, when the blow mold is closed, the blow mold halves squeeze off excess material not only on the bottom, but also in the shoulder and neck area. Unwelded seams of the outer container are thereby formed in the shoulder and neck area. In the bottom area the outer container is closed by a weld seam which has been formed by displacing material, the weld seam of the inner bag being fixed in said area. After negative pressure has been applied to the inner bag, holes are formed in the upper area of the outer container for the purpose of a permanent pressure compensation. All openings in the outer container are covered by the pump housing. The container operates reliably in the upside-down position.

Abstract: A method of securing a member to the interior of a blow-molded article including the steps of extruding a pliable tubular parison having interior and exterior surfaces; positioning the member within the parison; and contacting the member with the interior parison surface. A movable blow-pin urges the member against the parison wall. The member has a recessed attaching surface that interlocks with the parison wall to form a secure attachment.

Abstract: Heat-shrinkable cap comprising a heat-shrinkable tube sealed at one end by heat recovering that end of tube over a dimensionally stable, solid plug. The tube and plug are mutually weldable under heat, or are bonded together, thereby providing an air and water-tight seal at the sealed end. The open end of the cap may be internally coated with adhesive to provide an air and water-tight seal over an object such as a cable-end when the cap is heat recovered over said object.

Abstract: A parison molding method and its apparatus in which at least two kinds of materials are used, and the layer formation and dispersion are uniform in the weld part and in the circumferential direction. In the parison molding method and its apparatus, molten resin at a weld part within a parison head is discharged out of the parison head by way of a flow control valve.

Abstract: A travelling mold tunnel for forming double walled corrugated tube has a first portion for forming corrugated tube and a second belled portion for forming a cuff portion suitable for coupling with another tube. At the upstream end of the belled portion, radial small diameter passages are provided so that a pressure differential may be set up between the inside and the outside of a first parison within the belled portion. Thus, vacuum may be applied through the radial passages to allow an inner parison to laminate with the first parison over its inner surface in the belled portion. The first parison is drawn into the passages in protruding balloons. These may be ruptured. Alternatively, positive pressure may be used. In this case, the balloons may be ruptured inwardly.

Abstract: A die for co-extruding structural shapes is provided with a central cylindrical duct through which the molten polymeric material destined to constitute the central core of the structural shape flows, and a conical gap, coaxial with the central duct, into which the polymeric coating material is fed which will constitute the outer skin of the structural shape.

Abstract: A process for making a continuous fiber reinforced thermoplastic article that is sufficiently strong and rigid for use as a structural member includes the steps of providing a tubular composite parison that has continuous, axially oriented glass fiber filaments dispersed in a thermoplastic resin and admitting pressurized air into the interior of the tubular parison to expand the tubular parison to a desired shape.