Hoover Universal, Inc.

Owens-illinois, Inc.

Owens-illinois Plastic Products Inc.

Hoover University, Inc.

Michael Hirschberger

Thomas A Shapler

Thomas R Buehler

An extrusion head assembly for adjustably positioning a view stripe in a tubular parison to correct the view stripe positioning in situations where twisting of the parison prior to molding occurs. The apparatus includes an externally adjustable member which circumferentially positions the view stripe in the parison relative to the extrusion head assembly so that the view stripe will correspond with the mold parting line of a container blow molded from the parison. The adjustable member circumferentially positions the view stripe without causing the development of stagnation pockets in the stream of the plastic forming the view stripe. Degregation is prevented by dividing the flow of the plastic forming the view stripe into two streams which individually and continuously flow from a common inlet port to a common exit port.

Extrusion head with adjustable view stripe positioning

A multi-layer, multi-parison extrusion head in which nearly identical parisons are extruded from each extrusion station of the head when operated in an intermittent mode. Resin passages are provided within the extrusion head for supplying each of the resins to each extrusion station with the passages configured in a manner such that the ratio of resin volume for one resin in the passages for a given extrusion station compared to the volume of a second resin in the flow passages to the same extrusion station is the same for all extrusion stations while the volumes of resins feeding each station are not equal. As a result, a relatively simple configuration of passages is provided without requiring all of the passages to be of equal length.

Intermittent multi-layer multi-parison extrusion head

A sidefed die head for forming multiple tubular plastic parisons having a plurality of barrier walls contained in a matrix resin so as to form a plurality of discontinuous, substantially two dimensional barrier walls within the matrix resin which overlap one another so as to form a barrier to permeability. The die head includes a diverter sleeve for each parison to create two counter-rotating circumferential spiral flow channels of resin to form each parison wherein the barrier resin within the matrix resin is stretched to form streaks which are then elongated to form platelets within the matrix resin. The two spiral flow channels form parisons having two concentric layers, each layer having a radial weld line. By positioning the weld lines in each layer circumferentially offset from each other, a single radial weld line through the parison is prevented. The spiral flow channel also increase the impact strength of the container and improves the uniformity in the parison wall thickness.

Die head for plastic with barrier forming material

An extrusion device for producing an article of a heterogeneous blend of incompatible polymers, one polymer forming a matrix and the other being in a discontinuous phase within the matrix. The device is used with either side-fed or center-fed multiple parison die heads. The desired heterogeneous resin structure is formed and maintained by a unique extrusion screw and adapter configuration that avoids division of the melt stream to feed the multiple parison die head after formation of the desired resin structure. This is accomplished by a plurality of arcuate flow passages in the terminal portion of the extrustion screw directly feeding each die. The arcuate flow passages are formed by ribs that extend radially inwardly from the extruder barrel toward a flightless terminal portion of the screw shaft and tip. Circulatory resin flow in the arcuate flow passages driven by the screw rotation forms the desired laminar resin structure.

Multiple parison extrusion device for producing laminar articles

An extrusion die head for producing multiple layer tubular plastic bodies is disclosed in which the size of the tubular resin flow passage for at least one of the resin layers is infinitely adjustable at the point where two or more resin layers merge together to form a multiple layer stream. The adjustable passages are formed by two spaced inclined surfaces at the downstream end of the passages. The thickness of the passages is varied by axially moving one surface relative to the other. The moveable inclined surface is carried on an annular ring member mounted in the die head. In one embodiment, the ring is replaceable with another ring member to axially move the surface, thereby adjusting the layer thickness. In another embodiment, the ring member is threadably mounted in the die head so that rotation of the ring causes axial movement of the surface to adjust layer thickness. In the preferred embodiment the ring member is rotated by a drive mechanism operable from outside the die head for adjustment without disassembly of the die head. Adjustability of the gap sizes in the die head widens the range the relative thicknesses of the layers and widens the range of relative viscosity values that can be used. The versatility and usefulness of the die head is thus increased over that of die heads employing fixed gaps.

Improved multiple layer die head with adjustable gaps

Dual parison extrusion head for multi-layer extrusion blow molding in which a die body surrounds two parallel spaced mandrels to form two cylindrical passages from which parisons are extruded. A series of resin supply conduits are provided for directing each resin to both passages. The series of conduits are axially spaced in the extrusion head to direct a plurality of plastic resins to each of the passages to form a multi-layer parison. The resin supply conduits are symmetrical about a vertical plane transversely bisecting the extrusion head between the two passages to produce flow and thermal symmetry in the resin to balance the resin flow to both passages. The resin supply conduits are configured so as to produce the dual parisons with the resin weld line of the multiple resin layers being located on the blow mold parting line. The resin conduits are positioned to minimize the center distance between parisons to reduce the size of the extrusion head. This is accomplished in part by feeding the resin downwardly before the resin flows into the cylindrical passages to form the parisons.

Dual parison extrusion head for multi-layer blow molding

Apparatus for blow molding plastic containers with a longitudinal view stripe of a transparent resin in the side wall for visually monitoring the level of the contents of the container. The apparatus includes a plurality of die heads each of which includes a mandrel sleeve having a diverter for directing the flow of a pigmented resin around the mandrel sleeve to form a tubular parison, and for inserting a longitudinal stripe of a clear resin into the pigmented resin. The container mold halves are positioned relative to the parison such that the view stripe is located on the parting line of the mold halves such that the length of the view stripe along the top and bottom walls of the container is controlled.

Apparatus for forming a parison with a view stripe

A polymer composition and articles are disclosed wherein the composition comprises a low density polyethylene resin having a density between approximately 0.920 and 0.935 gram/cc and a melt index between approximately 0.5 and 1.0 grams/10 minutes, admixed with a linear low density polyethylene resin having a density between approximately 0.923 and 0.940 grams/cc and a melt index between approximately 0.75 and 5.0 gram/10 minutes. The composition is useful for forming article carriers, especially those used in carrying groups of metal cans.

Low density polyethylene and linear low density polyethylene blended

A process is disclosed for extruding heavy tubular shaped articles from high molecular weight, high density linear ethylene polymers under shearstress conditions such that the exterior surface of the extruded article would undergo melt fracture. Melt fracture is avoided by coextruding a thin layer of a second ethylene polymer in contact with the high molecular weight, high density linear ethylene polymer and the outer lip of the annular die. The second ethylene polymer has melt flow properties such that it does not exhibit melt fracture at the temperature and shear rate employed in extruding the tubular shaped article.

Growing community of inventors

Sylvania, OH, United States of America

Michael Hirschberger