Abstract: A multilayer plastic film or sheet having a series of component layers and optional bonding layers tying said component layers together is provided. The multilayer film or sheet comprises a central barrier layer comprising first and second layers of polyvinylidene chloride polymer bonded together with a tie or bonding layer, an outer layer adjacent to an outer side of the first PVDC layer, and a sealant layer adjacent to an outer side of the second PVDC layer.

Abstract: A multilayer plastic film or sheet having a series of component layers and optional bonding layers tying said component layers together is provided. The multilayer film or sheet comprises a central barrier layer comprising first and second layers of polyvinylidene chloride polymer bonded together with a tie or bonding layer, an outer layer adjacent to an outer side of the first PVDC layer, and a sealant layer adjacent to an outer side of the second PVDC layer.

Abstract: A multi-layer tubular film is co-extruded and cooled to form a first bubble, then collapsed, preheated and blown into a second bubble. The second bubble is further heated from outside to produce a decreasing temperature gradient from the outside surface of the film to the inside surface of the film. The outside surface of the film is hotter than the inside surface of the film and the inside surface of the f film is hot enough for re-blowing but sufficiently cool to avoid blocking. The film is then collapsed, blown into a third bubble and cooled to produce biaxially-oriented film, which is then collapsed, blown into a fourth bubble, heated and then cooled film to relieve stress and impart desired shrink properties to the film to produce ship-stable biaxially-oriented film.

Abstract: A multilayer film is herein provided. The film, which is useful for packaging, comprises: —a core barrier layer having an outer side and an inner side, said core barrier layer comprising one or more barrier polymers that exhibit moisture and/or oxygen barrier properties, wherein said barrier polymer is optionally coupled to a slow crystallizing polyamide or a polymer blend thereof; —an outer layer bonded to the outer side of the core barrier layer comprising a rigid polymer having an inherent viscosity (IV) in the range of about 3.2 to 4.7, wherein the outer layer optionally comprises slow crystallizing polymer (SCP) or a polymer blend thereof; and —a sealant layer bonded to the inner side of the core barrier layer comprising one or more polyolefins sufficient to provide a seal.

Abstract: A mixing section for an extrusion screw comprises a shaft having at least one set of spaced-apart cuspidate shaft teeth, with the shaft teeth extending radially outwardly from a root of the shaft. Each of the shaft teeth comprises a flank face and a rake face opposite the flank face, with the tooth transitioning between the flank face and the rake face at an outermost cusp. Some embodiments have one or more longitudinally extending, longitudinally spaced series of annular sets of circumferentially spaced shaft teeth. Some embodiments have one or more helically extending series of spaced-apart cuspidate shaft teeth. The mixing section may be received in a mixing section barrel to form a mixing portion of a screw extruder.

Abstract: A novel multilayer plastic film is provided comprising a series of component layers and optionally bonding layers to tie said component layers together, said component layers comprising: a central oxygen barrier layer, a first polymeric barrier layer on a first side of said central oxygen barrier layer, a second polymeric barrier layer on a second side of said central oxygen barrier layer, an outer layer adjacent the first polymeric barrier layer for providing mechanical strength, and a sealant layer adjacent the second polymeric barrier layer. At least one layer comprises two different polymers.

Abstract: A mixing section for an extrusion screw comprises a shaft having at least one set of spaced-apart cuspidate shaft teeth, with the shaft teeth extending radially outwardly from a root of the shaft. Each of the shaft teeth comprises a flank face and a rake face opposite the flank face, with the tooth transitioning between the flank face and the rake face at an outermost cusp. Some embodiments have one or more longitudinally extending, longitudinally spaced series of annular sets of circumferentially spaced shaft teeth. Some embodiments have one or more helically extending series of spaced-apart cuspidate shaft teeth. The mixing section may be received in a mixing section barrel to form a mixing portion of a screw extruder.

Abstract: A body member for an extrusion die for multilayer film has a passage-forming surface and an open feed channel formed in the passage-forming surface. The feed channel continuously decreases in depth from the feed channel inlet, and the feed channel is of substantially constant-width substantially rectangular cross-section along substantially its entire extent. Corners of the feed channel may be slightly rounded. Substantially constant-width feed channels of substantially rectangular cross-section may be used in blown film applications, in which case the feed channel extends in a spiral from the feed channel inlet, and in cast film applications, in which case the feed channel extends substantially linearly from the feed channel inlet. Dies can be assembled by arranging two body members with their respective passage-forming surfaces opposed to one another.

Abstract: An annular co-extrusion die for extruding multi-layer tubular plastic film has inner die mandrels stacked one upon another. Each die mandrel has a generally U-shaped cross-section with side walls extending substantially in parallel with the longitudinal axis of the die. The outer surfaces of the die side walls each have a series of helical shaped grooves formed therein. An annular outer die member surrounds the first inner die mandrel and the inner surface of the outer member and the outer surface of the first inner die mandrel form a longitudinally extending annular extrusion passage. Additional longitudinally extending annular extrusion passages are formed between outer and inner surfaces of nesting inner die mandrels.

Abstract: Packaging containing a PVDC barrier layer is manufactured without any significant orientation, with the result that the PVDC harrier layer remains flexible at significantly greater thicknesses than when it is oriented. This increased thickness compensates for the reduced barrier properties resulting from less crystallinity of the PVDC, and hence multilayer plastic tubing can be manufactured in which PVDC is used as a barrier layer instead of aluminum.

Abstract: Stretch film is treated by passing a web of tackifier-containing, unbloomed thin polymer film through a heater so that the web is heated to a temperature sufficient to cause tackifier bloom prior to the web reaching a next stage in an in-line process. Also, a pattern can be applied to a thin polymer film. An oriented web of thin polymer film is passed across at least one heated roller having the pattern engraved thereon to define face regions and relief regions collectively conforming to the pattern. As the web contacts each roller surface, portions of the web positioned over the relief regions receive less heat than portions of the web positioned over the face regions, thereby causing the respective portions of the web to undergo differential, heat-induced shrinkage which imparts the pattern to the thin polymer film.

Abstract: Apparatus for controlled shrinking of molten plastic sheet material comprises a series of parallel cylindrical rollers for moving the plastic sheet material from a first position to a second position. At least one heater is aligned with the rollers for maintaining the plastic sheet material in a molten state while the rollers move the plastic sheet material, and a drive mechanism rotates the rollers so that the tangential speed of the rollers progressively decreases from the first position toward the second position. As a result of the progressive decrease in tangential speed of the rollers, the speed of the plastic sheet material is progressively reduced as the plastic sheet material approaches the second position, so that portions of the plastic sheet material closer to the second position move toward the second position more slowly than portions of the plastic sheet material further from the second position.

Abstract: Stretch film is treated by passing a web of tackifier-containing, unbloomed thin polymer film through a heater so that the web is heated to a temperature sufficient to cause tackifier bloom prior to the web reaching a next stage in an in-line process. Also, a pattern can be applied to a thin polymer film. An oriented web of thin polymer film is passed across at least one heated roller having the pattern engraved thereon to define face regions and relief regions collectively conforming to the pattern. As the web contacts each roller surface, portions of the web positioned over the relief regions receive less heat than portions of the web positioned over the face regions, thereby causing the respective portions of the web to undergo differential, heat-induced shrinkage which imparts the pattern to the thin polymer film.

Abstract: Stretch film is treated by passing a web of tackifier-containing, unbloomed thin polymer film through a heater so that the web is heated to a temperature sufficient to cause tackifier bloom prior to the web reaching a next stage in an in-line process. Also, a pattern can be applied to a thin polymer film. An oriented web of thin polymer film is passed across at least one heated roller having the pattern engraved thereon to define face regions and relief regions collectively conforming to the pattern. As the web contacts each roller surface, portions of the web positioned over the relief regions receive less heat than portions of the web positioned over the face regions, thereby causing the respective portions of the web to undergo differential, heat-induced shrinkage which imparts the pattern to the thin polymer film.

Abstract: An interlocking sheet is formed from a resilient, flexible material. The interlocking sheet comprises a plurality of regularly spaced locking members projecting from a first side of the sheet. Each locking member is hollow and an aperture on the second side of the sheet opens into the interior volume of the locking member. Each locking member has a proximal portion adjacent the aperture, a medial portion further from the aperture than the proximal portion, and a distal portion further from the aperture than the medial portion. The maximum width of the medial portion is greater than the narrowest width of the proximal portion, measured in a common direction, and each locking member tapers from the medial portion to the distal portion. The locking members may be elongate linear locking members or discrete legs. A method and apparatus for making the interlocking sheets are also described.

Abstract: Stretch film is treated by passing a web of tackifier-containing, unbloomed thin polymer film through a heater so that the web is heated to a temperature sufficient to cause tackifier bloom prior to the web reaching a next stage in an in-line process. Also, a pattern can be applied to a thin polymer film. An oriented web of thin polymer film is passed across at least one heated roller having the pattern engraved thereon to define face regions and relief regions collectively conforming to the pattern. As the web contacts each roller surface, portions of the web positioned over the relief regions receive less heat than portions of the web positioned over the face regions, thereby causing the respective portions of the web to undergo differential, heat-induced shrinkage which imparts the pattern to the thin polymer film.

Abstract: Disclosed is a winder having: a drum about which a web passes in use; a cutter which severs the web as it passes around the drum into segments; a suction facility which draws air through a suction portion of the drum such that, when severed, the trailing web segment is carried by the suction portion to a release position; a loader which, for each segment, receives a core at a starting position whereat the core is rotated by contact with said drum and whereat the core receives the leading edge of said trailing segment, without fold-over, from said drum when the trailing segment reaches the take-up position; a guide which receives the core after the segment has started to wind thereupon; and a transfer mechanism which receives the core from the guide and supports same in driven contact with the drum as the segment is wound the Disclosed is a winder having: a drum about which a web passes in use; a cutter which severs the web as it passes around the drum into segments; a suction facility which draws air through