Abstract: A movable mold is movable toward and away from a fixed mold so as to close and open the mold. The fixed mold includes an intermediate plate facing a movable-side mold plate. This intermediate plate has a retainer-molding recess which cooperates with the movable-side mold plate to form a retainer-molding cavity, and a core pin, which cooperates with a housing-molding recess to form a housing-molding cavity, is mounted on the intermediate plate. A retainer, molded in the molding cavity, is moved downward by an ejector pin into a position where the retainer is disposed coaxial with a housing. Then, the two molds are again closed together, so that the housing and the retainer are connected together, and then this assembled product is taken out.

Abstract: A method of fireproofing a component of thermoplastic material belonging to an installation for distributing a flammable liquid such as a fuel, the method consisting in coating the outside of the component in a compound based on polyvinyl chloride (PVC) that is grafted so as to be cross-linked.

Abstract: Miniaturized planar column devices are described for use in liquid phase analysis, the devices comprising microstructures fabricated by laser ablation in a variety of novel support substrates. Devices formed according to the invention include associated laser-ablated features required for function, such as analyte detection means and fluid communication means. Miniaturized columns constructed under the invention find use in any analysis system performed on either small and/or macromolecular solutes in the liquid phase and may employ chromatographic, electrophoretic, electrochromatographic separation means, or any combination thereof.

Abstract: A method and an apparatus for unloading plastic material products from a plastic material injection molding machine are disclosed. The method comprises the steps of unmolding the products from a mold of the injection molding machine and, after the step of unmolding, cooling the products on two product surfaces by contacting the two product surfaces with two corresponding cooling surfaces of a cooling apparatus. The apparatus is provided with corresponding unmolding devices and cooling plates.

Abstract: A moving mold 100 consisting of slidable housing molds 110 and 110 and retainer molds 120 and 120 and a fixed mold 200 pairing with the moving mold 100 are used to mold a housing 20 and retainers 30a and 30b in resin at the same time. When the fixed mold 200 and the moving mold 100 are opened, the housing molds 110 and 110 are opened and a space is formed between the housing 20 and the retainers 30a and 30b to be fitted to each other. The retainers 30a and 30b are pressed against the housing 20 with the retainers 30a and 30b held in the retainer molds 120 and 120 from both the left and right sides, whereby the housing 20 and the retainers 30a and 30b are assembled.

Abstract: An apparatus and method are provided for manufacturing articles, such as syringe barrels, substantially free from contaminants. The apparatus is an enclosure defining at least a class 100 and MCB-3 environment, and includes a molding isolation module and a packaging isolation module. Any contaminants that may exist within the enclosure are removed by the use of horizontal and vertical laminar airflows directed into air filter units. Further, the molding temperature may be selected such that it renders the fabricated articles substantially free from contaminants. The molding isolation module and packaging isolation module keep the fabricated articles substantially free from contaminants from the time the articles are molded to the time the articles are placed in sealed containers for shipment.

Abstract: A method for the manufacture of intravascular stents of bioresorbable material comprises the following steps:preparing a viscous solution of poly-.beta.-hydroxybutanoic acid as a bioresorbable polymeric material in a solvent,successively coating a male mold core with layers of the polymer solution in several steps by precipitation of the polymeric material by the solvent being evaporated and by the layer previously precipitated being dissolved at least partially for a homogeneous stent blank to build up,drawing the stent blank off the male mold core, andsubsequently treating the stent blank to finish the shaping of the stent.

Abstract: A connector includes a connector housing and a retainer, which can be moved from a temporarily secured position to a fully secured position in the connector housing. The retainer secures a terminal in the connector housing and cannot be erroneous moved into the fully secured position. The connector comprises a connector housing with a retainer insertion hole in a front surface, which reaches flexibly deformable spaces of lances provided in cavities. The retainer is inserted into the retainer insertion hole and held in a temporarily secured position. After a terminal member is inserted into the housing, the retainer is further pushed into the retainer insertion hole and moved to a fully secured position, which restricts flexible deformation of the lances. The direction that the retainer is moved into the temporarily secured position is generally at right angles to the direction the retainer is moved from the temporarily secured position to the fully secured position.

Abstract: Miniaturized planar column devices are described for use in liquid phase analysis, the devices comprising microstructures fabricated by laser ablation in a variety of novel support substrates. Devices formed according to the invention include associated laser-ablated features required for function, such as analyte detection means and fluid communication means. Miniaturized columns constructed under the invention find use in any analysis system performed on either small and/or macromolecular solutes in the liquid phase and may employ chromatographic, electrophoretic, electrochromatographic separation means, or any combination thereof.

Abstract: A shoe that conforms to foot contours and provides cushioning is comprised of a shoe sole and a shoe upper attached to the shoe sole. The shoe upper is comprised of an outer layer, an inner layer and a conforming layer therebetween, wherein a first portion of the conforming layer is comprised of viscoelastic gel and a second portion of the conforming layer is comprised of environmentally-responsive gel. The environmentally-responsive gel is preferably a temperature-responsive gel that will react to the heat emanating from a foot inserted into the shoe to express a liquid. The viscoelastic gel is preferably a soft, flowable gel that conforms to foot contours.

Abstract: The present inventions relates to a mold for forming a one piece flip-top cap and process for making such a cap. A mold for forming and closing the one piece flip-top cap prior to ejection from the mold includes a first mold part, an inner core mold part and a second mold part movable into relationship with the first mold part and the inner core mold so as to form a mold cavity therebetween. The mold produces a one piece flip-top cap with a living hinge between the body and lid of the cap and which is maintained in a closed position upon ejection from the mold. Pull straps are used to ensure full closure of the cap lid to the body prior to ejection.

Abstract: A composite web structure utilizing a thin first layer of material having a plurality of structural fibers arranged to lie essentially in a unidirectional orientation. A thin second layer of material is positioned adjacent the first layer and includes a plurality of structural fibers. First and second layers are impregnated with a matrix material for binding fibers within the first and second layers and for binding the first and second layers together. The web may be formed into a composite structure such as a honeycomb core for fabrication into a panel.

Abstract: A method utilizes components from a kit for easily and conveniently obtaining a fingerprint impression which is subsequently used to create an accurate three-dimensional fingerprint replication. The kit, the components of which are used to practice the method comprises at least one unique finger sleeve, a base material and a catalyst for forming an amount of impression material, and instructions for using the kit to obtain the fingerprint impression using the finger sleeve and the impression material.

Abstract: A process and apparatus for forming a leak proof body and cap. The process including the steps of defining a mold cavity between a first mold part and a second mold part, injecting a molten material into the mold cavity thereby forming from the molten material a body and cap, and retracting the first mold part from the second mold part to separate the first mold part from the body and cap. Thereafter, engaging at least the body with a robotic arm and moving the body with the robotic arm into a capping device while the body and cap are at a temperature at which the material is not fully set. The body is then sealed by moving the cap into engagement with the body to form a leak proof seal.

Abstract: A method of producing a connector with a rear holder, wherein a housing 2 and a rear holder 3 are molded separately from each other by a set of molds 31 to 34. After molding, one of the molds (33) is moved to form a space between the housing 2 and the rear holder 3, and using another (34) of the molds, the rear holder 3 is moved toward the housing 2, thereby provisionally retaining the rear holder 3 on the housing 2.

Abstract: A method of making a sealing or guiding assembly for sealing or guiding a corner of a movable window glass, such as for the window in a motor vehicle door. The assembly comprises two lengths of sealing or guiding strip which are connected together to form a corner matching the corner of the window glass. The corner between the two lengths of strip is bridged across by a flexible flap which is produced by an in-situ molding operation forming part of the method. The two lengths of strip are placed into the mould which has a cavity matching the shape of the flexible flap but which is arranged so that the flap is connected to each sealing strip only over a small part of the total area of the sealing strip which is overlapped by the flap. The flap is therefore otherwise spaced from each sealing strip by a gap which, during the molding operation, is occupied by a plate which defines part of the mold cavity for forming the flap.

Abstract: An apparatus and method are provided for manufacturing articles, such as syringe barrels, substantially free from contaminants. The apparatus is an enclosure defining at least a class 100 and MCB-3 environment, and includes a molding isolation module and a packaging isolation module. Any contaminants that may exist within the enclosure are removed by the use of horizontal and vertical laminar airflows directed into air filter units. Further, the molding temperature may be selected such that it renders the fabricated articles substantially free from contaminants. The molding isolation module and packaging isolation module keep the fabricated articles substantially free from contaminants from the time the articles are molded to the time the articles are placed in sealed containers for shipment.

Abstract: A plastic beverage closure including a base wall, a peripheral skirt and a plurality of threads on the inner surface of the skirt for engagement with the threads of a container which may be made of glass or plastic. The plastic closure includes a compression molded seal extending about the periphery of the inner surface of the base wall and the juncture of the base wall to the peripheral skirt. The closure includes a central axially thickened portion; a channel surrounding the thickened portion and extending radially to an annular radially thickened portion on the skirt at the juncture with the base wall. A concave surface extends from the base of the channel and merges with the surface of the annular portion. A compression molded liner is provided on the thickened portion, channel and concave surface of the closure and defines a planar sealing surface of contact with the end surface of the finish of a container and an arcuate surface for engaging the arcuate surface of a container.

Abstract: A utility cart having a tool handle holding device for firmly holding the handle of a long handled lawn or garden tool to the side of the utility cart is disclosed. The device comprises one or more clips that are disposed below the rim of the bin of the utility cart. The cart and the clip(s) may be integrally molded from a suitable plastic material, such as high density polyethylene. Each clip is deformable within its elastic limit so that a tool handle may be insertingly forced into the clip wherein it is held within the clip, upon elastic contraction of the clip, by a tool retaining flange and a tool retaining lip. Removal of the tool handle from the clip is effected by removingly forcing the handle out of the clip whereupon the clip deforms sufficiently to allow the tool handle to pass between the tool retaining flange and the tool retaining lip. Upon removal of the handle from the clip, the clip then contracts to its pre-insertion, nondeformed condition.

Abstract: A method and an apparatus for stabilizing a microporous marking structure is disclosed. The method comprises the steps of placing a microporous marking structure in conjunction with an absorbent material within a stabilizing device. A positive pressure is then applied to the microporous marking structure within the stabilizing device until a sufficient amount of ink originally retained within the microporous marking structure is forced to flow therefrom into the absorbent material so that the microporous marking structure obtains a substantially stabilized state. The apparatus may comprise a pair of substantially rigid plates arranged for relative movement with respect to each other wherein at least one of the substantially rigid plates is adapted to support a microporous marking structure thereon until the microporous marking structure is arranged between the plates.

Abstract: Filaments made from a mixture of absorbable polymers and plasticizers are used to make surgical articles. Preferred plasticizers used in the mixture are stearic acid and its salts.

Abstract: A wrist support (10) and method for constructing the wrist support is described. The wrist support includes a base (12) with a cushion layer (14) mounted on the top surface (12A) and an outer covering (16) surrounding the base and cushion layer. The bottom surface (12B) of the base has an adhesive (13) which is protected by a release paper (15). The release paper is removed in order to secure the ends (16A) of the outer covering to the base. The wrist support is constructed from a sheet of base material (36) and a sheet of cushion material (38) which are cut into a wrist support preform (26) in a mold (20). The sheets are inserted between a first half (22) and a second half (32) of the mold with the base adjacent the second half of the mold. The first half of the mold is then moved downward into contact with the second half which causes the second half to also move downward and which enables the plunger (34) of the second half to extend into the indentation (24) of the first half.

Abstract: A method of fabricating a controlled and uniform cell size blotter roll for blotting liquid images consisting of toner particles and carrier liquid. The method includes the step of mixing a first grade of salt having first particles of a first uniform size with a polymer material so as to form a first mixture. The method next includes a step of extruding the first mixture to form an extruded sleeve having intimately compacted polymer material and salt particles, an outer surface, and an inner surface defining a hollow interior.

Abstract: A seal structure between a leg part 15 of a front lens and a seal groove 12, wherein a seal member 20 is applied into the seal groove 12 formed on a periphery of a front opening portion of a lamp body 10, the leg part 15 of the front lens engaging with the seal groove 12 is secured to the seal groove 12 by a mechanical fastening means (clip 30) to prevent a removal, and the seal member 20 in the seal groove 12 is compressed by the lens leg part 15, characterized in that the seal member 20 is formed of a solid foamed material which foams from an initial fluid state and hardens while keeping elasticity, and which can be stripped off.

Abstract: A method for forming a coved backsplash system, comprising two adjacent perpendicular wall sections joined by a curved corner joint. In particular, a designed relief, or groove, is formed on the rear surface of the material at a predetermined depth. The grooved material is placed on a shaped mandrel having the capacity of maintaining controlled heating, limited to the area being formed on the material. The grooved area is also heated by a device in conjunction with the surface area being heated by the mandrel. The solid surface material is brought to a thermoforming temperature by conductivity of the heat generated in the mandrel and heating devices. A wiping arm is used to form the solid surface material to the mandrel, the solid surface material being brought in contact with a flat work surface by the wiping arm. The non-grooved, flat surface areas of the material are then held in place by the wiping arm while the solid surface material begins the cooling process.

Abstract: A particulate plastics material, a polysaccharide and water are fed to an extruder which is operated under such heat and pressure conditions that upon emergence of the extrudate from the extruder die, the extrudate assumes a cross-section greater than that of the exit orifice of the die. The extrudate is then further processed, either by shredding to produce particulate material for feeding to filter-making section of a cigarette making machine, or by forming into smoking article filter rod lengths.

Abstract: A tamper-evident thermoplastic fitment having a spout and a closure for said spout are welded to a polymer-coated paperboard container or to a flexible plastic container. The fitment and closure are initially molded simultaneously but with a substantial space between the two parts interconnected by an elongated runner which conducts molten plastic from the closure to the fitment. Upon retraction of the core of the mold, the closure is pulled into the spout until shoulders on the parts engage, whereupon the closure is stripped from the mold core. The runner comprises a tear tab which slides through an apertured space on the closure. When the parts engage tangs on the tear tab engage the space, making the assembly tamper-evident. The fitment has a flange which may be welded or otherwise secured to the container. The tab may be pulled by the consumer to open the container. The closure may be unscrewed from the spout or otherwise disengaged.

Abstract: A decorative molding for a corner formed by a ceiling and a vertical wall comprises a thin strip of flexible plastic and is secured to the wall by an attachment allowing the molding strip along its upper and lower edges to be flexible to conform with uneven surfaces in the ceiling and/or wall. In one form the strip is attached to the wall by an adhesive. In another form, a wall track and clip arrangement is utilized to provide easy removal from the wall for paint or wallpaper application. A corner element is provided in one form in which ends of the strips are adhesively secured thereto in overlapping engagement. In another embodiment, the strips are telescopically connected to the corner element.

Abstract: A primary outer shell includes, in its most preferred embodiment, a base and a wall which includes at least one embedded foreign object and defines openings into an inner cavity containing a burnable candle member which causes the outer shell to glow and cast shadows without melting. The outer shell is constructed according to a unique molding method which includes at least partially immersing a swollen distensible mold, such as a water-filled balloon, into a reservoir of molding material, such as wax, to allow the molding material to form a molded shell around the distensible mold. After the distensible mold with the attached molded shell is removed from the reservoir of molding material, it is placed upon a flat surface to form a flat bottom into the molded shell.

Abstract: A cigarette packet of the rigid type having a hinged lid is fashioned in a mold, composed of a bottom die and a top die which combine to create two distinct voids and a slender channel by which the voids are interconnected. A moldable material is directed between the bottom die and top die, filling the voids and the channel completely and resulting in the formation respectively of a container, a lid, and a hinge connecting the lid to the container.

Abstract: A molding mechanism and method of using that mechanism for simultaneously forming, by injection molding, two molded parts intended to be interference fit together and then, while the two molded parts are still within the molding mechanism, repositioning them and fitting them together. The sequenced interplay of the moving parts of the molding mechanism which accomplishes this process may be controlled by either a two-part or a single-part camming mechanism. The two molded parts may be an actuator-overcap and a spray nozzle insert.

Abstract: A process for moulding a fastener formed from two members arranged one inside the other, in which the two members are moulded from a fluid plastic material within separate moulding cavities of the same mould with the use of a common cylindrical core so as to form the members separate from one another but facing each other axially. Subsequently, while the members are at a high enough temperature so as to ensure their high deformability, the mould is opened by the movement of respective parts forming the lower die so as to release only the first member, and the subsequent withdrawal of the core causes the insertion of the first member into a through-hole in the second member and, finally the core is withdrawn completely from the fastener. The latter is then expelled from the mould.

Abstract: A method of forming a textured surface in a sheet of photographic paper by washing the paper for a predetermined period of time, repeatedly cockling the sheet to form a plurality of randomly placed ridges and valleys in the paper, drying the paper, and compressing the paper in a press.

Abstract: An electrostatic RF absorbant circuit carrier assembly production method including the steps of forming a polymeric support structure having a base and surrounding walls which form an internal cavity from plastic, disposing a plurality of conductor paths within the cavity, forming a polymeric cover having wall members integrally fashioned into a surface thereof, for making contact with conductor paths within the cavity, depositing a layer of surface material on the cover and the cover wall members, said surface material comprising:a thermosetting binder,a non-conductive RF absorbing filler comprising 25 to 87 percent by weight loading of the binder, such that the surface material absorbs RF energy within a range of 1-60 GHz, anda conductive filler comprising 1 to 4 percent by weight loading of the binder and the RF absorbing filler, such that the surface material has a surface resistivity of 10.sup.5 -10.sup.

Abstract: An abrasive tool such as a grinding wheel or a saw is characterized by the working portion comprising a mass of ultra-hard abrasive particles dispersed in a non-porous thermoplastic polymer matrix. Examples of suitable thermoplastic polymers are polyetheretherketone, polyaryletherketone, poly (amide-imide), polyphenylene sulphide, liquid crystal polymer and mixtures thereof.

Abstract: A device for injection moulding plastic articles by the fusible-core technique includes a unit (1) for moulding fusible cores, a unit (2) for injection moulding, a unit (3) for melting and for recovering the fusible cores and a unit (4) for washing the moulded parts. The first two units are served by a mobile transfer robot (5) equipped with a rotatable arm having a ripper adapted to catch a fusible core and a gripper adapted to catch a moulded part. The two latter units are served by a stationary robot for melting (8) which interacts with the transfer robot (5). By programming the various functions performed by the robots, it is possible to carry out in parallel the moulding cycles of fusible cores and of injection moulding of the desired parts with a minimum of non-productive time and hence to obtain an automatic production with a high yield.

Abstract: A method for manufacturing a drip irrigation emitter, including the steps of molding onto an injection-mold core having at least n different active diameters, n different, axially spaced apart members of the emitter, at least n-1 of the members being substantially annular, the inside diameter of at least one of the annular members being a tight fit on the outside diameter of the next smaller of the members, stripping the members off the core, starting from the member having the largest inside diameter, thereby causing the members to be tightly nested one inside the other, in a predetermined axial and angular relationship, and ejecting the thus fully assembled emitter from the mold. There is also provided an injection mold for producing fully assembled multi-part drip-irrigation emitters.

Abstract: A method of fabrication of a sphincterotome, such as a papillotome, for surgical cutting using an electrically conductive cutter wire. The sphincterotome includes a multi-lumen tubular member, with one lumen having an electrical conductor disposed therein, and the other lumen having a reinforcing wire disposed therein. The reinforcing wire is preferably rectangular in cross-section, providing a greater moment of inertia in a resisting axis than in a bending axis. Accordingly, the cutting edge of the cutting wire may be oriented to the 12 o'clock position of the papillary orifice to avoid injury to the duodenal wall or pancreatic duct in the patient, and to maintain the cutting edge in a predetermined cutting plane. Fluoroscopic indicating stripes may be provided at the distal end of the sphincterotome.

Abstract: An injection molding apparatus and process for forming a plurality of first parts and a plurality of complementary second parts during a single molding cycle has a system for removing parts molded during each cycle and for assembling the parts into finished articles. The system includes a plurality of rotatable suction cups for removing the parts and for aligning them with and inserting them into a series of loading ports in a central mold member so as to mate respective ones of the first parts with respective ones of the second parts. The central mold member further has internal chute assemblies for conveying assembled articles away from the mold. A novel system for driving the rotatable suction cups uses a rotatable member mounted to various mold halves and a camming arrangement whereby relative movement of the mold halves during the mold closing and opening motions causes rotation of the suction cups.

Abstract: Apparatus and method for extracting tubular articles from their molds and inserting them into corresponding workpiece holders comprising a first orienting device for delivering the molded tubular articles in their molds to a first conveyer whereupon the axis of each mold and the tubular article therein has been rotated 90.degree., i.e.

Abstract: A tie-rod assembly used in a press having an inside fixed mold end plate, an outside fixed end plate spaced from the inside plate, a movable mold plate between the end plates, and an actuator for displacing the movable mold plate toward the inside mold end plate for pressing tools carried by the mold plates together in a closing direction and for moving the tools apart in an opposite opening direction includes a tie rod extending along an axis in the direction through the movable plate and having a threaded inside end and an outside end and a stationary threaded element carried on the inside end plate and axially aligned with the tie rod displaced by the actuator independently of the movable plate between a use position and a changeover position with the threaded end withdrawn in the opening direction and spaced from the inside end plate, a nut actuated by a rotary drive for screwing the nut in the changeover position from the tie-rod on the threaded element and inside and outside bracing devices engageable b

Abstract: Disclosed are electroactivated shaped articles, well adapted as cathode elements and composites, especially for electrolytic cells for the electrolysis of sodium chloride. The articles include a mass of fibrous material consolidated in a matrix of fluoropolymer binder wherein at least a portion of the fibers are electrically conductive. The shaped articles have a resistivity of less than 0.4 ohm cm, and have at least one electrocatalytically active agent uniformly dispersed therethrough. The electrocatalytically active agent(s) is (are) selected from Raney metals or Raney alloys depleted in fugitive metal values.

Abstract: An apparatus and method for aseptic, particle-free production of articles. A shroud is placed around at least a portion of the device which produces the articles to substantially isolate that portion from the external environment. The device for producing the articles and the shroud are sterilized and the air inside the shroud is filtered and sterilized. A laminar or other type of flow of filtered, sterilized air is imparted through the shroud over the articles being produced. A secondary shroud encloses the corridor or work area adjacent the shroud and device which produces the articles. The corridor and secondary shroud are sterilized, and sterilized and filtered air is continually introduced therein. The articles therefore are particle-free and sterilized for further use. The apparatus and method can be used for any component production process employing high temperatures and/or pressures, including, but not limited to, blow molding, injection molding, and production of semiconductor electronic components.

Abstract: A screen unit for a screening machine comprises a screen layer which is bonded to a screen frame spanning an opening thereof. The screen layer is uniformly heated before such bonding is effected so that cooling after bonding generates a tension in the screen layer to allow it to have a trampoline or drumhead vibratile action. The tension is maintained by a reinforcing frame embedded in the frame body.

Abstract: There is disclosed a cloth-like tape substrate. The substrate is made from an essentially unbonded cellulose web having a breaking length between about 0.71 km and 2.66 km which is saturated with a soft rubber-like polymer, coated with a low stiffness polymer, and then embossed. The unbonded web is formed from at least 25% by weight of pulp having R.sub.10 values greater than 94%. The soft rubber-like polymer has a glass-transition temperature between -50.degree. C. and 0.degree. C. and the low stiffness polymer coating has a tensile modulus less than 1,000 MPa.

Abstract: A method of forming a dispenser for delivering a beneficial agent to a biological environment. A beneficial agent and an expandable composition are placed in a capsule made of fluid dissolvable material. The capsule is closed and surrounded by a semipermeable wall which is permeable to fluid but not to the beneficial agent. Then a passageway is drilled in the capsule between the exterior and the interior which contains the beneficial agent.

Abstract: A mold for forming the vial and cap and for seating the cap on the vial prior to ejecting the vial from the mold is provided and includes a frame for the mold, a first mold half arranged on the frame, and a second mold half movable arranged relative to the first mold half so as to form a mold cavity therebetween. The mold produces a vial and cap including smooth radii provided at several locations to facilitate the seating of the cap on the vial.

Abstract: A weftless warp of yarns being drawn and wound on a beam is fed through a tension detector, located prior to the drawing step and responsive to tension in any of the yarns equalling a predetermined non-zero level, for stopping the process. This prevents damage to or breakage of a yarn which might have become snagged in the warp source.

Abstract: Method and apparatus for continuously forming articles and stacking them ready for formation of batches from the stack. Some of the articles are treated by being given a disfigurement which makes them identifiable in the stack so that batch lengths containing predetermined numbers of articles are clearly seen. These disfigurements are caused by moving a moveable element forming part of the forming surface of the machine whereby the surface shape is changed to cause change in shape of the articles. The invention is particularly useful during forming and stacking of shallow thermoformed thermoplastic articles.

Abstract: The specification discloses an apparatus and method for concurrently manufacturing at least two semiround tubing structures. An extruder including plasticizing means for a plurality of plastic resins extrudes semiround and linear strips of plastic material in generally two back to back D-shaped sleeves. Between the D-shaped sleeves, a strip of adhesively non-compatible material is extruded so that the D-shaped sleeves may be separated. The rounded portions of the D-shaped sleeves are molded in a continuous blow molding arrangement to form the top wall of the semiround tubing. The tubing is cooled, and the two semiround tubing lengths separated from the adhesively non-compatible strip inbetween. Optionally, the base of the semiround tubing may be perforated. The two lengths of semiround tubing are folded with the base inside the top wall and coiled into large reels.