Abstract: A method of forming a two-layer plastic pipe (4;8) to be laid in the ground for conducting material therethrough forms a core pipe (2) consisting essentially of a first plastic material and forms a detachable outer hose (3;7) of a second plastic material around said core pipe (2) by a suitable coating method, including in said second plastic material an amount of additives effective to protect said core pipe with said outer hose from stresses and loads of laying said core pipe and outer hose and usage thereof in ground.

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: This invention relates to a process for making laminar articles by blending multicomponent pellets of a heterogeneous blend of a barrier resin, typically a condensation polymer, and a compatibilizer with a polyolefin. The pellets advantageously prevent segregation of the barrier resin and the compatibilizer during processing. This provides uniform, reproducible laminar articles with improved barrier properties and mechanical properties. The articles exhibit good fluid barrier and mechanical properties.

Abstract: Disclosed is an evacuated and unevacuated microcellular foam containing an infrared attenuating agent (IAA). The evacuated foam has an average cell size of about 70 micrometers or less. The unevacuated foam has an average cell size of 1.0 micrometers or less. The IAA provide a greater proportional reduction in foam thermal conductivity in these foams than in foams of larger cell size. Further disclosed is a method of using the foams.

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: A crosshead die for an extrusion system provides a balanced, even flow of molten material around a circumference. The die has a cylindrical body with opposite first and second ends, an outer wall, a horizontal centerline and a vertical centerline. The die further includes a reduced diameter end portion at the second end thereof. The reduced diameter end portion includes an axial bore. The cylindrical body further has a recessed surface in the first end, and a circular groove in the recessed surface. The groove has an inner edge and an outer edge and the outer edge includes two inwardly curved blending wedges which are positioned in opposed relation on the vertical centerline. The inner edge of the groove merges into a frusto-conical inner wall which tapers axially inwardly and merges with the axial bore in the reduced diameter end portion. The inner edge of the groove has a lesser height than the recessed surface.

Abstract: An oriented multilayer film comprises a barrier layer of polymerized ethylene vinyl alcohol, and an orientation-compatible polymeric layer having a modulus of at least about 4.times.10.sup.4 psi. The a barrier layer occupies from about 2 to 15 volume percent of the oriented multilayer film, and has a thickness of from about 0.01 to 0.75 mils. The polymerized ethylene vinyl alcohol has an ethylene content of from about 38 to 48 weight percent. The orientation compatible layer has a thickness of from about 0.49 to 4.5 mils. The multilayer film is oriented at a temperature of from about 165.degree. F. to 212.degree. F., has an orientation ratio greater than 9, an oxygen permeability at 0% relative humidity of from about 1 and 6 cm.sup.3 -mil/day-m.sup.2 -atm, and a total thickness of from about 0.5 to 5 mils.

Abstract: A surface-segregatable, melt-extrudable thermoplastic composition is provided which includes at least one thermoplastic polyolefin and at least one additive having the general formula, ##STR1## in which: (A) R.sub.1 -R.sub.9 are independently selected monovalent C.sub.1 -C.sub.3 alkyl groups;(B) R.sub.10 is hydrogen or a monovalent C.sub.1 -C.sub.3 alkyl group;(C) m represents an integer of from 1 to about 4;(D) n represents an integer of from 0 to about 3;(E) the sum of m and n is in the range of from 1 to about 4;(F) p represents an integer of from 0 to about 5;(G) x represents an integer of from 1 to about 10;(H) y represents an integer of from 0 to about 5;(I) the ratio of x to y is equal to or greater than 2;(J) the additive has a molecular weight of from about 350 to about 1,400; and(K) the additive is present in an amount of from about 0.5 to about 5 percent by weight, based on the amount of thermoplastic polyolefin.

Abstract: Underground pipelines that carry wastewater, water, natural gas, and industrial fluids deteriorate with age. This invention is a process and apparatus for installing a thermoplastic liner in a dry pipeline to accomplish in situ rehabilitation. It involves extruding a tube of thermoplastic liner material within the interior of a dried and preheated pipeline in situ, said tube having an outside diameter smaller than the inside diameter of said pipeline. The tube is next expanded so that the outside diameter of said tube is substantially equal to the inside diameter of said pipeline. The expanded tube is then cooled and hardened in a liner configuration.

Abstract: A method for making a film which is useful in the packaging of newly formed blocks of cheese and demonstrates flexibility, extensibility, and improved sealing strength comprises extruding an ethylene vinyl acetate/very low density polyethylene sealing layer. In addition to barrier properties, flexibility and extensibility are, preferably, also provided by coextruding a core layer of ethylene vinyl alcohol copolymer containing at least 32% by weight of ethylene with the sealing layer.

Abstract: A method of manufacturing a multilayer heat-shrinkable, puncture-resistant biaxially oriented film is disclosed. The method includes a double bubble orientation step and extruding a primary tube that includes at least one substantially linear ethylene homopolymer or interpolymer, wherein the substantially linear ethylene homopolymer or interpolymer has an uniform branching distribution, a melt flow ratio, I.sub.10 /I.sub.2,.gtoreq.5.63, and a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63, and is also characterized as having essentially no linear polymer fraction, a single DSC melting peak, a density greater than about 0.85 g/cc, and a favorable gas extrusion critical shear rate at the onset of surface melt fracture.

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: Tubular, biaxially stretched, heat shrinkable multilayer film food casings comprising inner and outer polyamide layers on either side of a core layer predominantly of one or more polyolefins such as VLDPE or EVA and a coextrusion process for making the film.

Abstract: Apparatus for producing a tubular plastic product, for example film, has a die body with inner and outer die members defining between them an annular space, and a first inlet for feeding a first stream of resin into the annular space. The inner and outer die members define an annular chamber communicating between the first inlet and the annular space. The resin stream from the first resin inlet divides into two substreams which flow in the annular chamber in opposite directions about the longitudinal axis of the annular space and then join. A second inlet downstream of the first inlet feeds a second stream of resin into the annular space and over the weld line of the annular resin stream. The annular resin stream is expressed through an annular orifice to form the tubular film.

Abstract: A process of forming a spa shell by selecting a coextruded polypropylene sheet, selectively heating the sheet, vacuum forming the heated sheet on a deep draw female mold to form a molded spa shell shape, flame treating one surface of the molded shell shape, heating the flame-treated surface, and applying a layer of polyurethane foam to the heated surface.

Abstract: An apparatus for the manufacturing of plastic pipes has half shells of which two at a time combine as a pair to form a mold. It is provided with a temperature-regulating bell. Supply lines are formed as flexible supply hoses of temperature-resistant plastic material. A line conduit accommodating them is provided with a protecting tube, which accommodates the supply hoses and which is provided with a heat insulation towards an injection head.

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 process for producing an oriented blown film of a thermoplastic resin by blown film extrusion, carried out by blowing air into an extruded bubble of the resin extruded from a ring die to expand the bubble and cooling the expanded bubble with air from a cooling air ring, wherein blown film extrusion is carried out under such conditions that the ratio of (b) the final diameter of the expanded bubble to (a) the diameter of the bubble at the crystallizing temperature of the thermoplastic resin ((b)/(a)) ranges from 1.5 to 10. The process provides an oriented blown film excellent in strength, appearance, and heat shrinkage characteristics.

Abstract: A hollow plastic container including a coextruded translucent plastic outer layer, an opaque plastic inner layer, and a viewing stripe of translucent or clear plastic material extending longitudinally in the inner layer. In one form the container viewing stripe is in the inner layer made of clear plastic material placed behind a thin translucent layer. In another form, the stripe is made of the same translucent plastic material as the outer layer. In a further form an additional inner layer is provided of translucent or clear plastic material. The hollow plastic container is made by coextruding a parison of at least two plastic layers to form an outer translucent plastic layer and an inner opaque plastic layer, and simultaneously coextruding a viewing stripe in the inner layer and extending longitudinally of the parison. This method allows production of a distinct viewing stripe of the same nominal outside color of an otherwide opaque plastic container.

Abstract: A method for producing polymeric tubing which is resistant to permeation by organic material contained therein which has at least one region defined by a plurality of outwardly extending annular ridges. In this method, tubular polymeric material having a first outer diameter and composed of at least three overlying polymeric layers is introduced into a mold device upon exit of the tubular polymeric material from a suitable extrusion device, the surface of the mold device having at least one region defined by an annular depression in an essentially cylindrical surface. Once the tubular material is introduced, it is expanded to a second outer diameter such that the tubular material deformably contacts the mold surface. The corrugated tubular material then exits from the die device after completion of the expansion step.

Abstract: A novel process and novel apparatus for producing prestretched plastic film is presented. The method and apparatus are capable of forming a film from molten material and cooling the film to a non-molten condition so the film can be stretched. The cooled film is engaged and passed through a primary nip and second nip to plasticly and elastically stretch the cooled film to cold orient the film such that the film is stretched beyond the material's yield point. The cooled film is engaged with a plurality of idler rollers at a relatively low tension over a distance sufficient to allow the cooled film to relax to recover a major portion of its elastic deformation. Thereafter, the film is formed into a roll prior to being affixed to a unit.

Abstract: A method for producing a high strength multi-layered film excellent in heat resistance, shrinkability and stretchability and usable for wrapping of various articles which comprises at least five layers comprising a surface layer (S layer) mainly composed of at least one polymer selected from (A), (B), etc. and as inner layers at least one base layer (SBC layer) containing mainly a mixed composition comprising a combination such as (A)+(B)+(C), at least one core layer (H layer) containing mainly a polymer selected from (C), and at least one auxiliary layer (R layer) containing mainly at least one polymer selected from (A) and (B), with a proviso that when the R layer is placed-adjacent to the S layer, the R layer comprises the resin different from that of the S layer, said (A) being a low-density polyethylene or a copolymer of ethylene with a specific monomer, said (B) being a soft thermoplastic elastomer having a Vicat softening point of 80.degree. C.

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: The present invention relates to novel multi-layer coextruded thermoplastic stretch wrap films useful for the packaging or palletizing of goods. More particularly the films of this invention comprise at least three layers having two outer layers and at least one intermediate layer placed between the outer layers. The intermediate layer is formed from a high pressure low density polyethylene resin and the outer layers are formed from a linear low density polyethylene copolymer such as ethylene copolymerized with a minor amount of at least one C.sub.4 to C.sub.10 alpha-olefin, such as hexene-1, octene-1, decene-1, 4-methyl-pentene-1 and butene-1. The force required to stretch the novel films of this invention may be controlled by the thickness of the intermediate layer relative to overall film thickness, the melt index of the intermediate layer resin, the molecular weight of the intermediate layer resin or a combination thereof.

Abstract: The present invention relates to multilayer coextruded thermoplastic stretch wrap films useful for the packaging or palletizing of goods. More particularly the films of this invention include at least three layers, the three layers having two outer layers and an intermediate layer positioned between said outer layers, the intermediate layer comprising a mixture of a first linear low density polyethylene and a polyolefin selected from the group consisting of homopolymers of propylene, copolymers of propylene and ethylene and mixtures thereof and at least one of the two outer layers comprising a second linear low density polyethylene. The force required to stretch the films of this invention may be controlled by the ratio of polyethylene to the selected polyolefin of the intermediate layer, by controlling the thickness of the intermediate layer relative to overall film thickness, by controlling the melt flow properties of the intermediate layer polyolefin resin or by a combination thereof.

Abstract: A method for producing an extruded film article such as a bag, which is a blend of a thermoplastic polymer such as ethylene vinyl acetate and an olefinic oxide polymer such as poly(ethylene oxide), with a modifier such as liquid smoke absorbed in the blend. The modifier is transferable from the film to a receiving surface such as a food body in fluid transfer relationship with the film.

Abstract: A cross-oriented multi-layer laminated plastic film is produced by first providing a flattened tubular plastic film having a outer plastic film layer with a first melting temperature and an inner plastic film layer with a second melting temperature lower than the first melting temperature, the outer plastic film layer having a molecular orientation substantially in the direction of the length of the tubular plastic film. The flattened tubular plastic film is passed from an expanding station in an expanded condition along a predetermined path in the direction of the length of said film to a collapsing station in a continuous manner. The expanded tubular plastic film is rotated about the predetermined path as the film passes from the expanding station to the collapsing station to effect cross-orientation of the outer film layer in directions inclined to the direction of travel of the tubular plastic film.

Abstract: A system and process for producing a tubular multilaminate film having a plurality of bonded resin sheets. At least one of the sheets is formed from an annular resin stream of spirally extruded resin and at least one of the sheets is formed from an annular resin stream of non-spirally extruded resin.

Abstract: A method of manufacturing heat-shrinkable, puncture resistant, biaxially stretched thermoplastic films from very low density polyethylene (VLDPE). The film may be entirely VLDPE or it may be multilayer with an oxygen barrier core layer formed of material such as a polyvinylidene chloride copolymer or an ethylene vinyl alcohol copolymer, and two outer layers. One of these outer layers may for example be a blend of ethylene vinyl acetate (EVA) and VLDPE, and the other outer layer may be EVA. The film may be fabricated into bags suitable for packaging food articles such as frozen poultry, primal meat cuts, and processed meat products. The bags have high shrink and improved toughness.

Abstract: A process of expanding plastics film is disclosed, together with an apparatus for performing that process, in which expansion of the plastics film is performed under the control of a liquid providing a stable hydraulic mass, by the downward extrusion and drawing of the plastics film, and the final expansion thereof, exclusively under the influence of the static and dynamic pressure of a hydraulic mass, at a position spaced downwardly of the extrusion head, the hydraulic mass being one that remains in a liquid phase at all temperatures encountered during the step of lateral stretching of the plastics film, to the exclusion of vaporization of the hydraulic mass.

Abstract: The present invention is directed to a process for manufacturing a cladded optical fiber. The cladding and core are halide materials. An interface for inhibiting radiation scatter is provided at the boundary between the halide cladding and the halide core. The process steps include extruding a first halide or halide core from a first chamber, and extruding a second halide or halide cladding from a second chamber into contact with the halide core. The halide cladding is joined to the halide core at the boundary.

Abstract: A method of manufacturing a multi-layer hollow article which consists of extruding a multi-layer parison having at least a chief resin layer, a sub resin (barrier) layer, and an adhesive resin layer located between the chief resin layer and the sub resin layer. The adhesive resin layer is made of the same essential material as the chief resin material and of the same quality. The sub resin layer is cut off by the use of a raised extrusion pressure of the adhesive resin when the multi-layer parison has been extruded a predetermined length. The parison is received in a mold so that the cut off sub resin (barrier) layer lies within the mold below pinch offs. Flash is produced as a result of the molding. The flash consists of the chief resin material or the chief resin material and the adhesive resin material. The flash is recycled as part of the chief resin material. Collecting a flash of a hollow article made by a blow molding and rebirthing the flash a rebirth chief resin material.

Abstract: A composite parison generally cylindrical in shape and including two or more plastic materials different in characteristic is formed. Using this composite parison, a hollow plastic product of any desired shape having a locally different characteristic, such as in softness, heat-resistance or wear-resistance, can be manufactured with ease, for example, by conventional blow molding.

Abstract: This invention relates to extruding films made from vinylidene chloride copolymers. Specifically, this invention relates to a method for lowering the oxygen permeability and enhancing the thermal stability and enhancing the melt shear stability of packaging films having a layer of vinylidene chloride copolymer film by adding a processing aid such as an epoxy resin to vinylidene chloride copolymer of low molecular weight. The conventional stabilizer/plasticizer combination of epoxy resin and 2-ethyl-hexyl diphenyl phosphate may be employed with the vinylidene chloride copolymer. The layer of vinylidene chloride copolymer can be as thin as 0.18 mil.

Abstract: Apparatus and method for fabricating films and packages, especially films and packages containing a layer of vinylidene chloride copolymer. The preferred apparatus includes a coextrusion feedblock (20) in combination with an annular extrusion die (10) having an internal crosshead mandrel (11), and intervening spacing means for conveying the melt stream (24) from the feedblock to the die. The mandrel (11) has a cross-head groove (14), whose preferred design resembles elements of a rectangle. The inner surface of the outer die wall (19) preferably has an offset portion, including one of a pair of ramps (33A, 33B) traversed by the melt stream (24) as it leaves the groove. The die (10) maintains the melt stream in a single basic shape as the melt stream traverses the die. The VDC copolymer is shielded from the equipment surfaces beyond the VDC copolymer extruder. Equipment surfaces beyond the VDC copolymer extruder are protected from the VDC copolymer.

Abstract: The present invention provides a process for increasing the orientation rate during manufacturing a heat-shrinkable (oriented) polymeric film including: (a) introducing a pro-rad agent to a cross-linkable polymer by blending the cross-linking agent with the cross-linkable polymer, (b) extruding the blended cross-linkable polymer, (c) subjecting the extruded polymer to irradiation, (d) orienting the extruded polymer in at least one direction, and (e) recovering an oriented polymeric film, wherein (f) both the original amount of pro-rad agent and the dosage of irradiation are to an extent sufficient to provide an amount of cross-linking effective to accomplish an increased orientation rate during the orientation step.

Abstract: Underground pipelines that carry wastewater water, natural gas and industrial fluids deteriorate with age. Shown is a process and apparatus for installing a thermoplastic liner in such existing pipelines to accomplish in situ rehabilitation. It involves extruding a tube of thermoplastic liner material within the interior of a pipeline in situ, said tube having an outside diameter smaller than the inside diameter of said pipeline. The tube is next expanded so that the outside diameter of said tube is essentially equal to the inside diameter of said pipeline. The expanded tube is then cooled and hardened in a liner configuration.

Abstract: The invention relates to processes for producing biaxially oriented single-layered and multilayered films. The biaxially oriented single-layered film receives stresses in the range of 500 kg/cm.sup.2 to 1500 kg/cm.sup.2 each in the machine and transverse directions of the film. The multilayered film receives stresses in the range of 300 kg/cm.sup.2 to 1250 kg/cm.sup.2 each in the machine and transverse directions of the film. Thus, the molding stability in biaxial orientation of a nylon film is improved and the thickness accuracy of a resulting film is improved.

Abstract: The present invention is directed to a multilayered coextruded thermoplastic structure useful as a packaging material having a barrier layer of polyvinylidene chloride, a polycarbonate layer and an adhesive layer interposed therebetween. The polycarbonate resin of the invention is characterized by its low molecular weight. In a preferred embodiment the polycarbonate is further characterized by its special chain terminating agent.

Abstract: An electrical cable having a jacket surrounding a metal shield which, in turn, surrounds the cable core. The jacket comprises a polyolefin with a modifier provided by a carboxylic acid or anhydride thereof with the jacket lying in intimate overall contact with an outer surface of the shield and being bonded by the modifier throughout the overall contact areas to the shield.

Abstract: A plastic can, having a cylindrical sidewall with circumferential beads and a flange at each end is disclosed. The material of construction preferably includes a structural layer and a barrier layer; the thickness and dimensions of the wall permit lidding with metal lids and retorting of the filled can without leakage or collapse.

Abstract: A vertically movable blow molding arrangement includes a whole set of molds and mold plates, two blowing needle cylinders, a set of oil spraying structures, and a conveying machine. The whole set of molds and mold plates can close or open for receiving, pinching, sealing and inflating a plastic material to shape, and moves up and down vertically between an extrusion head and the conveying machine by means of oil pressure. The whole set of molds and mold plates can automatically inflate the material without air blowing for shaping.

Abstract: A hot drawn multilayered structure including a layer of an ethylene-vinyl alcohol copolymer composition containing 70 to 95 wt % of EVOH having an ethylene content of 25 to 60 mol % and a saponification degree of at least 90%; and 5 to 30 wt % of an aliphatic copolymer polyamide containing capramide as a main structural unit, having a ratio of the number of methylene gorups to the number of amide groups satisfying the equation:6.6.ltoreq.CH.sub.2 /NHCO.ltoreq.10having a melting point of 110.degree. to 180.degree. C. and exhibiting a melt index of 0.1 to 10 g/10 mins.; having a thermoplastic resin layer on at least one surface of said layer. The multilayered structure has excellent gas barrier properties and minimized variability in gas barrier properties measured in different areas and minimal gel, hard spots, etc.

Abstract: Multiple lumen tubing is extruded by first extruding an inner tube of molten plastic about a metallic, bore-forming mandrel wire, followed by extruding about the inner tube an outer tube of molten plastic having a lumen formed by air mandrel means, with the inner and outer tubes being bonded together. This may be accomplished by means of a mandrel which is positioned in an extrusion die, with the mandrel defining a distal end portion positioned and shaped to form a lumen in the tubing, and an air flow passage extending through the mandrel to provide an air mandrel to the newly formed lumen to prevent its collapse. The distal end portion of the mandrel may be carried by an intermediate neck portion which has at least one transverse dimension that is less than the corresponding transverse dimension of the distal end portion.

Abstract: A method of making a fire hose including the steps of extruding a tube having inner 12 and outer coverings of elastomeric material on a woven jacket made from woven synthetic textile yarns and having a weft which is unusually highly crimped. The extruded tube is placed in a confining mould or sheath having an internal diameter substantially the same as the external diameter of the hose, curing the material of the tube by internal application of heat and pressure, pressing the outer covering into tight engagement with the sheath. The sheath effectively prevents radial expansion of the hose during the curing and the outer covering is thus embossed with the surface topography of the inner surface of the sheath upon removal of the sheath. The hose thus formed has good diametral swell properties and consequently reduces the frictional forces in relation to the amount of water flowing through the hose.

Abstract: A blow molding mold for making a hollow double-walled product includes male and female mold members movable toward and away from each other. The female mold member has a bottom and has first and second pairs of confronting peripheral wall segments, the wall segments of the second pair being pivotal relative to the bottom between open and closed positions. In one embodiment, the peripheral wall segments of the first pair are fixedly coupled to the bottom. In a different embodiment, the wall segments of the first pair are also pivotal between open and closed positions, and have expansion prevention walls which project outwardly from opposite sides thereof and which, when the wall segments of the first and second pairs are in their closed positions, project outwardly beyond the peripheral wall segments of the second pair.

Abstract: A method of producing an oxygen barrier film, and the resulting film, includes the coextrusion of a multi-layer extrudate having an outside ethylene vinyl alcohol copolymer layer which has been passed through a hot water system to soften and wet the ethylene vinyl alcohol copolymer. The wetted film can be more easily oriented to produce a shrinkable film.

Abstract: The present invention relates to multi-layer coextruded thermoplastic stretch wrap films useful for the packaging or palletizing of goods. More particularly the films of this invention include at least three layers having two outer layers and at least one intermediate layer placed between the outer layers. The intermediate layer is formed from a high pressure low density polyethylene resion and the outer layers are formed from a linear low density polyethylene copolymer such as ethylene copolymerized with a minor amount of at least on C.sub.4 to C.sub.10 alpha-olefin, such as hexene-1, octene-1, decene-1, 4-methyl-pentene-1 and butene-1. The force required to stretch the films of this invention may be controlled by the thickness of the intermediate layer relative to overall film thickness, the melt index of the intermediate layer resin, the molecular weight of the intermediate layer resin or a combination thereof.

Abstract: The invention concerns a process and an apparatus for the production of hollow bodies from thermoplastic material, the wall of which is in the form of a laminate, by extrusion blow molding. Tubular preforms for making the hollow bodies are first produced in an intermittent mode of operation, the wall thereof also being in the form of a laminate which includes a suitable number of layers. Within an extrusion head having an annular storage chamber for receiving the laminate-formation preform and an annular piston for emptying the storage chamber, the flows of material for forming the layers of the laminate of the preform are passed through the annular piston into the storage chamber in which they combine to form the laminate. The width of the outlets at which the flows of material issue from the annular piston can be so selected that it is proportional to the thickness of the respective layers to be formed therefrom in the laminate produced in the storage chamber.

Abstract: A coextruded, heat shrinkable, thermoplastic multilayer film for packaging fresh red meat cuts and processed meats. The film is produced by coextruding a multilayer structure which includes a first layer comprising very low density polyethylene, a first core layer of vinylidene chloride-methyl acrylate copolymer, and a second layer comprising very low density polyethylene. In another embodiment the first layer is a second core layer confined between said first core layer and a first outer layer comprising a heat sealable thermoplastic polymer or copolymer. In a further embodiment the second layer is a second core layer confined between said first core layer and a second outer layer comprising a thermoplastic polymer or copolymer.