Abstract: A layered film of thermoplastic material and method of manufacturing the same are disclosed. The film is defined by a plurality of superposed layers, the material forming a pair of adjacent layers having molecular chains oriented in certain directions which respectively cross each other at an angle in a range of between 5.degree. and 90.degree.. The film is manufactured by heating solid thermoplastic material to its softening point, conveying the viscous molten mass so formed while mechanically working the same to an annular material shaping opening of a rotary die or matrix from which the material is discharged in the form of a tubular segment which is directed into the nip defined by a pair of rotating stretching cylinders which flatten the tubular segment to form the layered film and which are rotated at a speed which tends to orient the molecular chains in an axial or machine direction.

Abstract: A system of automatically controlling the size of thermoplastic blown film to minimize scrap generation by guiding the bubble at an elevation above the melting point of the bubble, to keep it centered above the extrusion die, sensing when the bubble is too wide or too narrow and automatically actuating a means to selectively remove or deliver gas or air to or from the bubble to return the bubble to the predetermined desired diameter of width and sensing when the predetermined diameter or width is obtained.

Abstract: A process for simultaneously, biaxially orienting tubular ethylene polymer film by expansion and extension of the tube under particular conditions for heating the expanding tube, to give a heat shrinkable film. The heat shrinkable film has excellent heat shrinkability, shrinkage stress, transparency, heat sealability and impact resistance, and is very suited for use in shrink packaging.

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: A process for reducing melt fracture formed during extrusion of a molten narrow molecular weight distribution, linear, ethylene polymer, which comprises extruding said polymer through a die having a discharge outlet defining an exit die gap formed by opposing die lip surfaces and wherein one surface of the die lip and/or die land in contact with the molten polymer extends beyond the opposing surface of the die lip and/or die land in the direction of the axis of flow of the molten polymer through the die exit whereby melt fracture is reduced on the surface of the polymer leaving the extended die lip surface.

Abstract: A nozzle ring of an extruder for blowing tubular plastics film is divided into correcting 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 cross-sectional area corresponding to the number of correcting sectors is established from the measured thicknesses. Assuming that the film sector of maximum or minimum thickness has been extruded in the correct position for the purpose of determining the correcting sector associated with the film sector, the subsequent film sectors of equal cross-sectional area are in turn allocated to successive correcting sectors. The throughput and cross-sectional area or temperature of the respective correcting sector is adjusted until the circumferential lengths of the film sectors are equal.

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 from the measured thicknesses. 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. From the measurements, the mean thickness distributions are determined over the individual film sectors. These values of mean thickness distribution define a measure for the correcting command for the adjusting elements of the cooling sectors that are associated with the respective film sectors.

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: An assembly at an extruder for controlling the width of a two-layer web flattened from a tube extruded from a rotating or oscillating head of the extruder comprises monitors for detecting the velocity and edge-positions of the web upon transport thereof away from the extruder. A control circuit calculates the deviation of the actual web width from a predetermined width and emits a correction signal relayed via a stationary infrared-radiation transmitter and a receiver on the extruder head to valves controlling the pressurization of the extruded tube by a blower also mounted on the extruder head.

Abstract: The invention relates to a tubular film for packing foodstuffs that in the state in which they are introduced into the tube are paste-like or fluid and that either after packing are heated to approximately 70.degree. to 95.degree. C. or are packed in the hot, fluid state. The tubular film consists of at least one aliphatic polyamide, of which the glass transition temperature of .gtoreq.321 K in the dry state can be lowered, by moisture absorption, to 293 K, or of a mixture of this polyamide with at least one ionomer resin, wherein the ionomer resin may be partly or completely replaced by a modified ethylene/vinyl acetate copolymer. The tubular film according to the invention lies wrinkle-free against the contents after cooling. The tubular film is produced by shaping the plastic or plastic mixture and subjecting to biaxial stretching according to processes that are known per se.

Abstract: Extrusion of a homogeneous single phase fusion melt of acrylonitrile polymer and water through a circular die into a steam-pressurized solidification zone enables the tubular film formed to be drawn longitudinally and expanded transversely to provide a biaxially oriented barrier film especially suitable for food wrapping.

Abstract: An apparatus for producing tubular plastic films having extremely small variation of flat width in stabilized manner is provided. Said apparatus comprises a blower, a valve for controlling the amount of air, an air reservoir, a connecting pipe for connecting these blower, valve and air reservoir and another connecting pipe which connects said reservoir to the inside of a bubble formed on the tip end of a mold fixed to the outlet of an extruder through said mold to feed or discharge the air into the inside of said bubble continuously in a non-step manner, thereby to keep the inside pressure of said bubble uniform.

Abstract: A method for rendering initiation of stretching easier in the production of biaxial stretched film of plastic tube carried out by enclosing gas in said tube and by the difference in the peripheral velocity between delivery nip rolls and take-up nip rolls is provided. This method is characterized by passing said tube between at last one pair of nipping means for enclosing gas, having therebetween a clearance adjustable in the range of 1.about.10 mm. The nipping means are provided before or behind said take-up nip rolls and driven at a peripheral speed same as that of said take-up nip rolls.

Abstract: A method is disclosed for preparing polypropylene endless loop by blow-moulding polypropylene raw materials into tubular sheet, drawing the same transversely to an extent to provide a draw ratio of at least 4, and before or after the drawing step, cutting the tubular sheet to form individual endless loops, then twisting the cut and drawer loops to provide a twisted endless loop. The preferred polypropylene endless loop product is also disclosed.

Abstract: A die assembly of the present invention for extrudable materials includes a first member providing an external wall of a continuous cavity for passage of the extrudable material, a second member providing the internal wall of the cavity, a bushing for directing the flow of extrudable material within the cavity in one axial direction, a distributor interposed within the cavity, providing a restricted space therein for passage of the extrudable material, and a channel formed between the bushing and distributor through which the extrudable material flows axially and peripherally. The die assembly of the present invention can be modified for the coextrusion of two or more layers.

Abstract: A method for reducing sharkskin melt fracture during extrusion of a molten narrow molecular weight distribution linear ethylene polymer which comprises extruding said polymer through a die having a die gap greater than about 50 mils and wherein at least a portion of one surface of the die lip and/or die land in contact with the molten polymer is at an angle of divergence or convergence relative to the axis of flow of the molten polymer through the die.

Abstract: Described is a mildly biaxially oriented, blown polyethylene film characterized by a cross directional (CD) shrink force in the range of about 60 to 300 psi, an average heat seal energy of at least about 2.0 in - lbs., an average internal tear resistance of at least about 30 gms/ply, and a minimum shrink temperature no higher than 220.degree. F. and which is less than crystalline melt point (or points) of polyethylene material. This film also has a shrink force in the machine direction (MD) which is typically in the range of about 200 to 300 psi.Also described is the process by which this film is produced.

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: Films, 0.5-10 mils thick, which are rapidly and completely soluble in cold water, and which are suitable for use as packaging film in automatic packaging equipment, can be prepared by conventional melt extrusion processes when prepared from a novel composition consisting essentially of 5-20 parts by weight of a polyethylene glycol (having an average molecular weight in the range between 325 and 550) in 100 parts by weight of a partially hydrolyzed low molecular weight polyvinyl alcohol.

Abstract: A method for reducing the melt fracture during extrusion of a molten narrow molecular weight distribution ethylene polymer which comprises extruding said polymer through a die having a die gap greater than about 50 mils and wherein at least a portion of one surface of the die lip and/or die land in contact with the molten polymer is at an angle of divergence or convergence relative to the axis of flow of the molten polymer through the die.

Abstract: A method and apparatus are disclosed for the manufacture of a web of foamed thermoplastic material. The material web is extruded to form a tubular member and then expanded by action of a compressed fluid so that the outside of the tubular member is forced against a calibrating element arranged adjacent the tubular member. The tubular member is then cooled to a temperature below the softening temperature of the material and then is cut and converted into web form.

Abstract: In a film blowing plant comprising an extruder for the melt, a film blowhead, calibrating means for the blown tubular film, oscillatory take-off means for the film and a coiler for the flattened film, the output of the plant is set to an optimum figure by a process computer controlling the width and thickness of the film. The height of the line of solidification of the film above the blowhead is measured and, in response to a departure of this height from a given desired value, the output of the extruder is increased or reduced as the case may be.

Abstract: A process for making film from a narrow molecular weight distribution low density ethylene hydrocarbon copolymer, which process comprises extruding said copolymer through a die gap of greater than about 50 mils. The film exhibits an excellent balance of optical and mechanical properties.

Abstract: A process for manufacturing thermoplastic materials having an elevated gas impermeability and/or improved physical properties. This process is characterized in that it comprises mixing at least partially incompatible polymers, gelling them by the combined action of heat, pressure and kneading. The gelled mixture is then subjected to laminar flow through substantially parallel surfaces in which the ratio of the length of the surfaces to the distance between them is greater than 10.A thermoplastic material having increased gas impermeability as well as containers made out of said materials.A packaging method in which the thermoplastic materials of the invention are used to package oxygen sensitive materials.

Abstract: This invention relates to the production of tubular articles, made from synthetic thermoplastic materials, which resemble wood, rattan, bamboo, cane, reed, wicker, reed, rush, and similar natural materials, and also to the production of furniture, structures, and every kind of ornament in general employing thermoplastic materials which replace the natural materials mentioned above, coloring and veining such thermoplastic materials, and also joining and securing by means of ties made from rigid, semi-rigid or plastified polyvinyl the natural and artificial materials above mentioned, for the purpose of assembling furniture and structures in general.

Abstract: Polymer sheets or films are provided with tear paths that are substantially indistinguishable from the remainder of the polymer sheet or film in outward appearance and in chemical properties. Throughout the tear path, molecular chains of the polymer are oriented generally along a predetermined axis, while the molecular chains of the remainder of the polymer sheet or film are oriented generally differently from said predetermined axis. Such tear paths are typically formed by means of a device that extracts heat from the polymer as it is extruded or otherwise molded, the extraction rate being faster than the rate at which the remainder of the molded polymer is cooled in order to encourage maintenance of the substantially monoaxial orientation of the polymer chains along the tear path when the entire polymer is subsequently blown up or otherwise reoriented.

Abstract: The present invention provides a process for the manufacture of a polyethylene film having improved tear strength in the transverse direction. The process involves extruding a partially crosslinked polyethylene into film having a thickness between 10 and 100 .mu.m, by a blown film process. The blow-up ratio is in the range of 1.2:1 to 4:1 and the MD draw-down ratio is in the range of 2 to 60. Polyethylenes used in the present invention had prior to being partially crosslinked a density in the range of 0.940 to 0.970 g/cm.sup.3 and a melt index in the range of 0.2 to 15.0 g/10 min. The polyethylene is crosslinked to an extent sufficient to provide a film having an Elmendorf tear strength in the transverse direction substantially less than the tear strength of film made from the uncrosslinked polyethylene. Crosslinking may be accomplished using any known method e.g. by irradiation, through use of crosslinking agents.

Abstract: An apparatus for the manufacture of transversely contoured tubing from thermoplastic material. The tube emerges in the plastic state from an extrusion nozzle and is guided into a mold composed of a plurality of mold sections in series, with inner side working surfaces forming the transverse contours. Each of the mold sections is composed of two mold halves which are arrayed along a straight molding run in two confronting rows and which are circulated. In the circulation, the first two mold halves are moved apart and out of the molding run at the end of the molding run and are guided to a return run on which they are separately returned to the beginning of the molding run where they are rejoined to the preceding mold half. The mold halves are guided on the return run in a continuous, accelerated and then decelerated movement by a transfer mechanism which couples and uncouples from the mold halves as actuated by pneumatic cylinders under the control of limit switches.

Abstract: This invention is a process for making a self-welding packaging film by blending at least two ethylene polymers, one of the polymers having a melt flow substantially greater than any of the other polymers in the blend, and thereafter extruding a film from the blend. The film may be self-supporting or it may be an inner layer in a multi-ply film. Preferred ethylene polymers for the blend are the ethylene-vinyl acetate copolymers wherein one copolymer has a melt flow of less than 5.0 and the other has a melt flow greater than 28.0.

Abstract: The present invention is concerned with the art of manufacturing film from synthetic thermoplastic resinous materials, and more particularly relates to an improved method and apparatus for the manufacture of thermoplastic resinous film in tubular form.

Abstract: Apparatus is provided for preparing continuous, seamless blown thermoplastic film tubing by extruding a melt of the thermoplastic through an annular orifice into a tubular shape, inflating the film tube thus formed and cooling such inflated tubing. In the apparatus, the extruded tube while still plastic is passed through an external cooling means having one or more multi-perforated air rings shaped in congruance to the desired shape of the inflating tube. Additionally, final cooling means is provided which cools the precooled film tube with air supplied from a continuous, non interrupted annulus surrounding the tube. A major advantage of this apparatus is that production speeds can be increased while maintaining bubble stability.

Abstract: A method of producing a curved sausage casing by treating a sausage casing before curving with caustic solution and neutralizing the casing while in the curved configuration.

Abstract: In a blown tube process of producing thermoplastic film or sheeting, the blown tube is collapsed by passing it through a trapezoidal frame assembly to change the circular cross section of the tube to a square cross section. The square cross section tube passing from the trapezoidal frame assembly is then passed through a predeterminedly controlled flattening transition section to a pair of nip rolls in a manner that the film arrives at the nip rolls with minimal stretching.

Abstract: Composition and method for improving the thermoplastic processing characteristics of poly(ethylene terephthalate) (PET) in amphorous form are disclosed, as well as PET with improved melt strength.

Abstract: In order, in the molding of corrugated thermoplastic tubing, to overcome the disadvantage that pressurized air which is supplied to a zone within the tube of thermoplastic material as it is extruded from an extrusion head into the entrance of a tubular mold tunnel may tend to cause rupturing of the tube at the area immediately adjacent to the extrusion head where the tube is unsupported by the wall of the tubular mold tunnel the pressurized gas is supplied at a low pressure to a first zone within the tube of thermoplastic material to support the tube against the wall of the tunnel, and pressurized gas at a higher pressure is supplied to a second zone within the tube to urge the tube outwardly into the corrugations of the tubular mold tunnel. A first sealing arrangement separates the first zone from the second zone which is disposed downstream of the first zone, and a second sealing arrangement defines the downstream end of the second zone.

Abstract: a process is provided wherein polyethylene is melt-extruded in tubular form while simultaneously maintaining an environment of an inert gas such as nitrogen internally of the tubular form of polyethylene to preclude formation of a layer of large spherulites.