Abstract: A process for extruding biaxially oriented high density polyethylene film in which an additional secondary gaseous cooling medium is applied at strategic strain inducing locations of the blown bubble to control the final product properties of the extruded material.

Abstract: Apparatus including an extruder, a die member and a vacuum device connected in series. The vacuum device includes a chamber and a device at at least the outlet thereof to air-tightly seal the chamber around the extruded mass of foamed thermoplastic resin. The air-shielding or sealing device is an annular tube which is inflatable radially inwardly having a flexible inner face which seals around the extruded mass. A durable, abrasion-resistant, flexible protective sheet can be interposed between the mass and the tube.

Abstract: Extruded web multiple panels are produced with undulated webs by extrusion of a thermoplastic material by a device including an extruder, a slotted die connected thereto which comprises core pieces in the die slot for forming the webs, a movable mold channel placed downstream of the slotted die, and a removal device. The undulation of the webs is produced by friction forces rhythmically alternating in direction crosswise to the extrusion direction. The friction forces are allowed to act in the mold channel on the extrudate in an area where it is still above its softening temperature. The friction forces are produced either by a rhythmic crosswise movement of the entire mold channel or by movable sections of the mold channel walls of a special mold channel.

Abstract: Apparatus for cooling plastic film or sheet obtained by blowing tubing, comprising at its intermediate section an intensive blowing ring for directing air towards the tubing and at its upper section an upper chamber in which the tubing is in contact with an air flow directed in the drawing direction of the tubing. At the lower section of the apparatus is a non-closed lower chamber provided with at least one opening. The apparatus can be used to form blown films having superior optical properties, particularly clarity and turbidity, from a large number of resins.

Abstract: A method of making a tendon suitable for use in the post-tensioning of concrete as well as for other applications is disclosed. The method comprises the steps of coating a wire or a multiple-wire strand with a thin coat of a corrosion inhibitor. In the preferred embodiment, the thin coat may be more easily applied by coating the wire or multiple-wire strand with a thick coating of corrosion inhibitor and then removing the surplus amount of the corrosion inhibitor from the outer periphery of the strand, including the interstices, to leave the desired thin coat. A seamless plastic jacket is then formed around the wire or the multiple-wire strand while simultaneously creating a differential pressure across the wall of the seamless plastic jacket to provide a loosely fitting seamless plastic jacket.

Abstract: A high stalk blown film extrusion apparatus and method is described which produces a stabilized high stalk for increasing the production rate of blown, low to high molecular weight polymers, while increasing the film's physical and mechanical properties. The high stalk is stabilized by application of high velocity, low volume flow rate of air over the interior and exterior surfaces of the extruded film.

Abstract: Wire which has been coated with a polymeric material is useful in a wide variety of applications. One such application is as a winding for electrical equipment such as motors, transformers, magnetic coils, relays and the like. Generally, coated wires of this type have been prepared by coating the wire with multiple layers of a solution of the coating material. It has been determined that metal wires can be satisfactorily coated with a specific type of thermoplastic composition in a single layer without using solvents. This process utilizes a tubing type cross-head die with the thermoplastic composition comprising a mixture of 80% to 99% by weight polyethylene terephthalate and from 1% to 20% by weight of polyethylene, polypropylene, or a mixture thereof.

Abstract: A process for producing an air-permeable film, which comprises:(a) biaxially stretching a tubular unstretched film of a composition comprising 42 to 87 vol % of a thermoplastic resin and 58 to 13 vol % of an inorganic filler along a truncated-conical mandrel;(b) blowing a gas over the outside of the biaxially stretched tubular film to cool said film; and(c) simultaneously blowing a gas continuously into the tube of the film so as to penetrate the gas through the film and go outside.

Abstract: A curing mold for curing glass fiber pipe insulation contains alternating positive and negative pressure zones and hot curing gases are introduced to the glass fibers during advancement through the positive pressure zones, and the curing gases are exhausted from elongated exhaust openings in the mold during advancement through the negative pressure zones, and the exhaust openings are cleaned without interrupting the advancement of the glass fibers through the curing mold.

Abstract: A vat under vacuum bears in its sidewall a sizing sleeve, the cylindrical downstream portion of which includes annular channels interconnected by distribution channels. Injection ducts leave the bottoms of the annular channels and open out in the inside surface of the sleeve. The interior of the sleeve communicates with the interior of the vat via rows of radial suction ducts. During operation, the injection ducts are supplied with water under pressure which forms a film between the outside of the tubing and the inside surface of the sleeve even when the tubing is pressed against that inside surface owing to the partial vacuum prevailing within the vat.

Abstract: A collapsing frame for collapsing an extruded tube of plastics material to flattened form employs two converging frame members each having a large number of parallel rows of rollers mounted with their axes of rotation transverse to the direction of movement of the tube. Each row consists of a large number of small diameter, short length rollers of low density material mounted closely side-by-side to provide a continuous engagement surface, but freely rotatable independently of one another on the common axle. The rollers are of low friction, high temperature resistance material such as polytetrafluorethylene or nylon. The new frame results in better surface appearance owing to absence of scratches and reduction of wrinkling, and better tracking of the tube through the frame. There is also an unexpected improvement in flatness believed due to better support of the tube.

Abstract: Elastomeric hoses are vulcanized by a process wherein the outer surface layer (sheath) is completely vulcanized while the remainder remains unvulcanized. The surface layer and part of the resistant structure are maintained in an elastic elongated state while vulcanizing the remainder of the hose. An apparatus for vulcanizing the hose in accordance with the process is disclosed.

Abstract: In the manufacture of an inflation film for forming a thermoplastic resin having a melt tension of not more than 4 g into a tubular bubble, a tubular bubble extruded from an extruding nozzle is cooled from the inner circumferential surface thereof by air supplied from a first air supply opening. The outer circumferential surface of the bubble is cooled with air from a first external air-cooling ring arranged at the outside of the bubble. The first air-cooling ring has a guide plate for guiding the bubble, a second air supply opening for supplying air between the guide plate and the bubble from an inlet port arranged at the lower end of the guide plate, and a third air supply opening for supplying air to the bubble from an outlet port arranged at the upper end of the guide plate. The bubble which is cooled by the first external air-cooling ring is further cooled by the air supplied from a second external air-cooling ring. The bubble is solidified.

Abstract: A tubular film process wherein molten resin is extruded from an extrusion die into a tubular resin, blown by an internal pressure, cooling air is discharged at least at a point between the vicinity of the extrusion die and the vicinity of a bubble expansion ending point in a direction of the extrusion of the resin and in a direction opposite to the extrusion of the resin to, thereby cool the tubular resin, and the tubular resin is continuously taken up upon being cooled and solidified. The cooling air has higher flow rate in the extrusion direction. The cooling air is discharged not only in the direction of the extrusion of the resin but also in the direction opposite to the extrusion of the resin, whereby hot air stream is prevented from accompanying the flow of the resin, thus enabling to effectively cool the tubular resin.

Abstract: The invention contemplates the manufacture of a wrinkle-free, amorphous, unoriented polyester film which is produced by an extrusion blowing process. The process consists of extruding a bubble of polyester, expanding the bubble, and then collapsing the bubble at a temperature above the polyester's glass transition temperature to prevent the formation of wrinkles. The collapsing step is effected through the use of a shroud which receives the bubble and has a low friction surface.

Abstract: An improved method and apparatus for fabricating insulated cables, particularly polymeric insulated electrical power cables, resistant to the formation and growth of electrochemical trees is disclosed. Internal pressure on the conductor side of the cable is maintained lower than the external pressure on the outer surface of the insulation during extrusion. Extrusion pressure higher than the external pressure results in expansion of the insulation following extrusion. This expansion or swelling reduces the number and size of cracks and voids which are precursors of electrochemical trees. In addition, pressure curing the extruded, insulated cable with a curing medium above its melting point followed by gradual gradient cooling under internal pressure and higher external cooling fluid pressure to around room temperature optimizes the resistance of the cable to nucleation and growth of electrochemical trees.

Abstract: The upper and lower ends of numbers of curved cooling pipes are rotatably supported in the variable-type bubble water cooling apparatus according to the present invention. The cooling water is supplied to the pipes. The diameter of enveloping circle formed by these curved cooling pipes at a determined horizontal position is varied by relatively rotating the upper and lower support members of pipes. Thus, as the diameter of bubble passing portion of the apparatus can freely be varied, bubbles of variety of sizes can be produced by a single apparatus. Also, the cooling effects and positions are constant and the produced bubble has no unevenness of its thickness.

Abstract: Apparatus for making profiled plastic tube and comprising two circulating endless chains, each making a plurality of mold halves move along with a tube coming from an extruder, these mold halves pairwise constituting a mold cavity in which the tube is being given its profile. According to the invention the molds are movable relative to the chain links in a direction perpendicular to the direction of movement of the links. The machine frame is provided with guides for the mold halves, some located interiorly, others exteriorly, with respect to the chain loop, such that once closed, the cavity formed by the pairs of mold halves will remain closed and undisturbed up to the end.Preferably the transitions between curved portions and the operative portion of the path of the mold halves at the entrance and the exit ends are bending points of mathematically calculated paths and the operative straight path tangentially joins said transitional portions.

Abstract: A process for forming a blown film from a thermoplastic resin wherein a source of cooling air is induced to flow from the atmosphere in contact with another source of pressurized cooling air whereby increased production rates can be obtained.

Abstract: A process is disclosed for forming blown film of a low strain hardening polymer, such as a low pressure polymerized-low density ethylene copolymer, including an improved film bubble expanding technique which permits high production rates to be achieved with good film bubble stability. Advantageously, most of the films produced by the process have a relatively high degree of film clarity.

Abstract: The present invention relates to a method and apparatus for the extrusion of thermoplastic film which comprises extruding a melt of thermoplastic through an annular orifice to form a bubble or tube and while the tube is still in a semi-molten condition, passing the tube through a cooling and stabilizing means which surrounds the tube and is characterized by having a variable diameter to accommodate varying sizes of tubing.

Abstract: A plastic film is formed by annealing a molten tubular film in a first enclosed space and immediately thereafter directing cold air perpendicular to the axis thereof and expanding and solidifying the film in a second enclosed space while in contact with cold air flowing parallel to film travel.

Abstract: A guide assembly for blown plastic tubes to guide and support the tube after its extrusion from a die consists of a frame carrying a plurality of pairs of vertically-extending members distributed circumferentially around the tube. Each of the vertically-extending members carries a plurality of vertically-spaced parallel radially-inwardly-extending arms. Each arm of one vertical member of the pair cooperates with a respective arm of the other member of the pair, each cooperating pair of arms having a flexible wire support member extending between these ends, the wire engaging the tube and conforming to its circumference. As the tube diameter decreases the arms are moved simultaneously radially inward by opposite rotation of the respective vertical members, whereupon the wire conforms to the new reduced diameter, and vice-versa. The actual contact of the support member with the tube is by side-by-side cylindrical rollers (e.g. of nylon) threaded on the wire.

Abstract: A process for the manufacture of a flat-shaped hollow body through the use of a forming die, wherein mold segment halves move continuously along a forming die and which, upon entering the forming die, are moved in an operating direction facing each other in pairs in a closed mold in tight proximity to each other. The mold is injected with warm thermoplastic hose stock which is shaped under vacuum action in the mold. In order to produce flat-shaped hollow bodies on a continuous basis the hose stock is subjected to vacuum action over at least a portion of its cross section even before mold segment halves are brought together and is pressed together accompanied by the formation of welds and the creation of hollow spaces over a portion of its cross section.

Abstract: Reduced breakage and reduced internal gas pressure is achieved in the trapped bubble process for the preparation of film by applying vacuum to the region of the tube where the bubble starts to form.

Abstract: A nozzle ring of an extruder for blowing tubular plastics film is divided into cooling sectors provided with adjusting elements. The thicknesses of the blown film are measured over the circumference thereof and a number of film sectors of equal circumferential length corresponding to the number of cooling sectors is established. Assuming that the film sector of maximum or minimum thickness has been extruded in the correct position for the purpose of determining the cooling sector associated with the film sector, the subsequent film sectors are in turn allocated to successive cooling sectors. The mean thickness distributions are determined from the measurements over the individual film sectors.

Abstract: A casing of stretched plastic material, whether or not filled with a fluid such as gas or air, is wound with some tension about a smooth heated mandrel. During its curved path of travel said casing is on the one hand subjected to a contact or a radiation heat and on the other hand to a convection heat, said contact radiation heat prevailing during a period of time which is greater than that of the convection heat, thus causing the inner curved portion of the said casing to set during the time that the outer portions of the casing windings have already cooled down, so that smooth curved surfaces are obtained.

Abstract: An apparatus for making biaxially stretched tubular films of thermoplastic synthetic resin which permits operation in a stabilized manner and economically by using the hot air used in stretching a bubble again in heating a raw film. In said apparatus, a suction ring is provided in the section where a heated raw film is inflated by the gas filled therein under pressure, and the diameter of the resulting stretched bubble reaches its maximum diameter. The suction ring sucks the air used for heating the stretching part simultaneously with the air used for cooling it after stretching to attain a thermal interception effect between the stretching part and the cooling part after stretching. Air flow around the stretching bubble is made uniform.

Abstract: A stretched plastic casing is tensioned by means of a fluid medium after having been introduced into two clamping rollers, and conveyed to a bending member in front of or at the location of which it is subjected to a thermal treatment such, that it is bent out of its original path, while being thermally deformed, and is subsequently conveyed in the same direction of curvature, in a bent form, so as to be cooled down.

Abstract: A process and apparatus are disclosed for forming blown film of a low strain hardening polymer, such as a low pressure polymerized-low density ethylene copolymer, including an improved film bubble cooling technique which permits high production rates to be achieved with good film bubble stability. The disclosed process comprises cooling a molten film bubble by contacting the outside of the film bubble with separate annular streams of cooling fluid fed through at least two stacked annular cooling rings disposed around the film bubble, wherein all or substantially all of the cooling fluid exits the system through a common plane formed by the last cooling ring.

Abstract: Provision is made for evenly controlling the cooling of the inner die pin of an extrusion die assembly so that the hot plastic coming in contact therewith is frosted. A conduit extends through the inner die pin to a point near the tip of the inner die pin. A cap is mounted on the end of the conduit and spaced from the front face thereof to provide an annular discharge opening. At least the tip portion of the inner die pin is formed of a material of good heat conductivity, such as brass, and the cooling air is directed through the discharge opening relatively evenly over the inner portion of the inner die pin to effect uniform inside frosting of a plastic tube formed in the apparatus. The inside of the plastic tube is open to the atmosphere.

Abstract: A molten thermoplastic resin is extruded in the form of a double-layer cylindrical hollow film with the two film layers being interconnected with each other by a number of spaced legs and is then immediately passed through an annular gap defined by annular side walls of inner and outer vessels in such a manner that the two film layers are in contact with the respective side walls defining the gap. Coolant is supplied to the inner and outer vessels and overflows above the side walls to bring the coolant into contact with the resin. The level of the coolant overflowing above both side walls is adjusted to be equal and also to have a liquid pressure on the extruded resin balanced with a gas pressure supplied in between the two film layers and the legs of the extruded resin.

Abstract: The present invention relates to a process for extruding a thermoplastic sheath in the form of a tubular film provided with perforations and to a device for carrying out the process, according to which the extruded film passes over a skirt through which are blown jets of hot air provoking the perforation and formation of openings in the film; in the areas where the film is not to be perforated, air jets are also blown through channels of smaller width, therefore with a reduced pressure, so that the jets do not provoke the perforation of the film but form an air-cushion facilitating the flow of the film on the skirt; the channels are supplied from a pneumatic chamber with interposition of a rotary distributor formed by a ring made of graphite or self-lubricating material. The invention is applicable to the manufacture of partially perforated tubular films with a view to making packings.

Abstract: An apparatus for producing biaxially stretched tubular films which enables heating air for stretching to pass uniformly around the circumference of a stretching bubble thereby to effect stabilized operation. Said apparatus comprises 1 a circular hood fitted to the section where a loaded raw film starts stretching and a formed stretching bubble expands to its maximum diameter, 2 holders for a plurality of rolls, which holders are mounted on the lower part of said hood, said rolls being held each on the end of said holders which an elasticity allowing swinging of said rolls only in the direction radial to the central axis of said bubble but resistant to being distorted in the direction of circumference of said stretching bubble, and 3 a flexible and shrinkable cylindrical sheet attached to and along the inside lower surface of said hood, the lower end of said sheet being situated immediately above the roll part of said holders.

Abstract: A method and apparatus for extruding a radiant energy heat exchanging panel structure having a multiplicity of parallel passages extending longitudinally therethrough defined by a multiplicity of longitudinally extending integrally interconnected exterior and interior thin wall sections, in which the temperature of the plastic material moving longitudinally away from the extrusion outlet is reduced by flowing fluid into said passages and on the exterior sides thereof, by contacting the exterior sides with pairs of cooled rollers, by rolling a liquid medium upon the operative exterior side, and by flowing a liquid spray thereon to provide a radiation absorbing coating on the exterior side of the panel structure opposite from the operative side thereof. Certain of the flowing fluids are reactant fluids which chemically react with the hot plastic material or condense thereupon to form molecular coatings thereon enhancing the properties thereof as a panel structure.

Abstract: A method for manufacturing retortable cans is taught which includes the step of cable extruding a tube of plastic. Subsequently, a substantially gas-tight material is laminated to the outside of the tube and a plastic layer is laminated to the layer of substantially gas-tight material. Preferably, the gas-tight material comprises a metallic foil.

Abstract: What is disclosed are methods and apparatus for coating a hollow synthetic resin tube with a pre-formed film coating by applying the film coating to an exterior surface of such a tube directly after extrusion, while the resin thereof is thermoplastic, and then passing them through a shaping channel while maintaining a modest pressure differential between the interior and exterior of the tube, whereby the film coating and tube are adhered by the compression thereof against the walls of the shaping channel.

Abstract: In the method of the present invention preferably an apparatus is connected directly on-line with an extruder to inject fluid into or to remove fluid from a fresh extrusion on a continuous basis as the latter is extruded. In one case the fluid injected is a catalyst that causes curing of a mixture of particulate matter and resin binder. In the method one part of a two part binder mechanism is mixed with a particulate material, and the mixture is extruded on a continuous basis. The second part of the binder then is injected into the fresh extrusion on a continuous basis downstream of the extruder output to cure the extrusion. The extruder die also may include fluid injecting paths, on the one hand, for injecting lubricant or, on the other hand, for injecting of the second binder part, e.g. catalyst, into the relatively less dense material near the upstream end of the die.

Abstract: The woven tubing is continuously advanced and is opened and backed from the inside in a certain region, in which plastics material tubing which is larger in diameter than the woven tubing is extruded and oriented around and is forced in a soft condition against the woven tubing and then cooled.

Abstract: What is disclosed is a method and apparatus for forming a radially expanded and stretched tube of synthetic resin having a plurality of longitudinal-support members, corrugated in the longitudinal tube direction, joined to and extending between two opposing tube walls, by extruding the tube such that that areas of the opposing walls extending between two adjacent support members comprise alternating thick and thin wall portions in the longitudinal direction and every thin portion has a laterally-adjacent thick wall portion, whereby on subsequent stretching and expansion, the thick and thin wall portions stretch disproportionately and deform the support members attached thereto unequally to effect their corrugation in the longitudinal direction.

Abstract: In a blown film process for manufacturing plastic film bags, the shape of the film bag being formed is dynamically controlled by sensors provided at specific locations. At these locations, any deviation of the bag shape from the ideal shape will result in significant differences in quality of the produced film bag, or may result in a break of the film bag. Such deviation in shape is prevented by using the output signals from the sensors to control various process parameters.

Abstract: In the manufacture of fiber-reinforced cellulose casing wherein a paper tube is passed downwardly over a mandrel, impregnated with viscose and subjected to the action of a coagulating liquid to regenerate cellulose, a gas stream is flowed upwardly within the tube as the tube is passed over the mandrel, the gas stream pressure being sufficient to maintain the cylindrical dimensions of the tube but insufficient to cause a measurable change in the dimensions of the tube walls whereby contact of the internal surface of the impregnated tube with the mandrel is reduced or substantially eliminated.

Abstract: A vacuum sizing apparatus is positioned downstream from an extruder along a path followed by a body of thermoplastics material as the body exudes in a heated, deformable state from the extruder. The apparatus includes structure defining an elongate sizing surface extending along the path of travel of the body. A multiplicity of vacuum channels are formed in the structure and open through the sizing surface for drawing outer wall portions of the body into conforming engagement with the sizing surface as the wall portions cool and rigidify while moving along the sizing surface. The structure includes a plurality of side-by-side structural segments, each of which defines a portion of the sizing surface, adjacent ones of which have mating side walls. The vacuum channels are of small cross section and are formed as grooves milled or ground in the side walls of the segments. A clamping system releasably clamps the segments together and permits their disassembly to provide access to the vacuum channels for cleaning.

Abstract: The method permits selective cooling of tubular plastic material as formed to provide for an exchange of internal cooling air through the central opening of the blow head. Air supply rings having outlet slots facing the tubing, as well as air guide surfaces of small axial length, are provided inside the tubing and spaced from the annular die orifice to serve to support the tubing. The interior cooling air supply rings have axially directed passages for the flow of cooling air while the exterior air supply ring or rings deliver air at higher temperatures to provide a substantial thermal differential between the tube surfaces as formed to provide a flare-top edge upon severance. Also, the method permits forming a foam-film composite of thermoplastic materials by the blown bubble co-extrusion process.

Abstract: .Iadd.An improved extrusion method is provided to produce plastic tubes having at least one end thereof an increased wall thickness. The method includes the steps of continuously advancing plastic material through an extruder to form a cylinder, cooling the extruded cylinder as it passes from the extruder, periodically increasing the speed at which the plastic material is fed to the extruder relative to the speed at which the cylinder is drawn from the extruder to produce a section having an increased wall thickness and dividing the cylinder thus formed. .Iaddend.