Method of extrusion blow molding into paperboard inserts to form a composite package

• US 5,169,470 A
• Filed: 07/30/1991
• Issued: 12/08/1992
• Est. Priority Date: 09/22/1989
• Status: Expired due to Fees

• Current Assignee: Meadwestvaco (WestRock Company)
• Original Assignee: Westvaco Corporation (Meadwestvaco Corporation)
• Inventors: Goldberg, Barry A.
• Primary Examiner(s): Silbaugh, Jan H.
• Assistant Examiner(s): Timm, Catherine
• Application Number:
  US07/741,195
• Time in Patent Office: 497 Days
• Field of Search: 264/509, 264/511, 264/515, 264/516, 264/543, 264/152, 264/159, 264/161, 264/163, 425/503, 156/244.14, 156/244.19, 156/244.22, 156/245, 156/285, 156/287, 156/250, 156/264, 156/530, 156/251
• US Class Current: 156/244.14
• CPC Class Codes: B29C 2049/4635 being sterile
• CPC Class Codes: B29C 49/04 Extrusion blow-moulding
• CPC Class Codes: B29C 49/24 Lining or labelling
• CPC Class Codes: B29C 49/36 rotatable about one axis
• CPC Class Codes: B29C 49/70 Removing or ejecting blown articles from the mould
• CPC Class Codes: B29C 51/267 Two sheets being thermoformed in separate mould parts and joined together while still in the mould B29C49/0691 takes precedence
• CPC Class Codes: B31B 2105/00 Rigid or semi-rigid containers made by assembling separate sheets, blanks or webs
• CPC Class Codes: B31B 2110/10 having a cross section of varying size or shape, e.g. conical or pyramidal
• CPC Class Codes: B31B 2120/10 provided with covers, e.g. lids
• CPC Class Codes: B31B 2120/402 by applying a liner to already made boxes, e.g. opening or distending of the liner or the box
• CPC Class Codes: B31B 50/81 Forming or attaching accessories, e.g. opening devices, closures or tear strings
• CPC Class Codes: B32B 27/10 of paper or cardboard
• CPC Class Codes: B65D 5/2047 trapezoidal, e.g. to form a body with diverging side walls B65D5/2033 takes precedence
• CPC Class Codes: B65D 5/28 with extensions of sides permanently secured to adjacent sides, with sides permanently secured together by adhesive strips, or with sides held in place solely by rigidity of material
• CPC Class Codes: B65D 5/56 Linings or internal coatings , e.g. pre-formed trays provided with a blow- or thermoformed layer to protect the articles from mechanical damage B65D81/127
• CPC Class Codes: Y10T 156/1052 with cutting, punching, tearing or severing
• CPC Class Codes: Y10T 156/1054 and simultaneously bonding [e.g., cut-seaming]
• CPC Class Codes: Y10T 156/1075 of plural laminae from single stock and assembling to each other or to additional lamina

Abstract

The vessel portion of a gas-tight container suitable for packaging fresh foods is produced as a composite of paperboard and polymer film. A pair of folded paperboard blanks, pre-cut and pre-formed, are inserted into the opposite halves of split mold elements to a blow molding machine. Vacuum orifices in each mold half unit temporarily secure the position of a respective paperboard blank. The paperboard lined mold halves are closed upon a hot, extruded parison of malleable polymer leaving an end portion of the parison tube projecting from the closed mold unit. A fluid conducting needle penetrates this projected end portion to inflate the parison with an apppropriate blowing gas. Such inflation expands the malleable polymer, seamlessly and creaselessly, into the internal corners and crevices of the folded paperboard blanks. Following chilling, the mold unit is opened and the pair of paperboard blanks are ejected as a singular unit, joined by a molded flange of the continuous polymer film. Finally, the two polymer coated paperboard vessels are separated by trimming about the flange.

Claims

1. A method of manufacturing articles capable of fluid containment comprising the steps of:

providing a continuous supply line of pre-cut article blanks formed of 0.007 to 0.035 inch thick paperboard having press applied graphics on a predetermined exterior surface of said blank, each article blank within said continuous supply line having score lines for fold forming to a fluid containment configuration with an interior vessel surface opposite of said exterior blank surface;

providing a plurality of divided blow mold units on a mechanism for cyclically positioning and removing said units relative to a coextrusion polymer parison head, each of said mold units having respective pairs of half sections which comprise wall boundaries for respective cavities therewithin and means for cyclically opening and closing said half sections;

inserting a pair of said article blanks that have been pre-folded along said score line against cavity walls respective to an open pair of mold unit half sections whereby said exterior blank surfaces face a cavity wall and said interior vessel surfaces face the cavity bounded by said wall;

extruding a plural layered parison of diverse polymers between said pair of interior vessel surfaces while said pair of half sections are open;

closing said pair of mold unit half sections around said parison; and

,

inflating said parison against said pair of interior vessel surfaces whereby said interior vessel surfaces, internal corners and crevices are coated with a continuous, seamless and creaseless fluid barrier of laminated polymer film having a thickness about half of said paperboard thickness.

2. A method of manufacturing articles as described by claim 1 wherein said article blanks are held by vacuum against said respective cavity walls.

3. A method of manufacturing articles as described by claim 1 wherein exposed portions of said respective cavity walls remain within a separation space between said opposing pair of shaped article blanks when said parison is inflated whereby a continuous band of laminated polymer film is formed against said exposed cavity wall portions between said separated article blanks.

4. A method of manufacturing articles as described by claim 3 wherein independent film coated articles respective to said pair of shaped article blanks are obtained by trimming said continuous band.

5. A method of manufacturing articles as described by claim 3 whereby said continuous band of film between said shaped article blanks is partially trimmed to leave a hinge portion of film connecting said pair of shaped article blanks.

6. A method of manufacturing articles as described by claim 3 whereby said continuous band of film between aid shaped article blanks is trimmed about the band perimeter thereof and subsequently fused along a perimeter increment to provide a hinge portion of film connecting said pair of shaped article blanks.

7. A method of manufacturing articles as described by claim 1 wherein said article blank vessel surfaces are delineated by respective flanges about the perimeter thereof formed as an integral continuation of said paperboard, said polymer film coating continuing integrally from said interior vessel surface onto an adjacent surface of said respective flange.

8. A method of manufacturing articles as described by claim 7 wherein said opposing pair of article blanks are oriented within said respective blow mold cavities with said film coat receiving flange surfaces in spaced, facing opposition.

9. A method of manufacturing articles as described by claim 8 wherein exposed wall portions of said respective mold cavities remain as an outer boundary of a separation space between said opposing pair of film coat receiving flange surfaces when said parison is inflated whereby a continuous band of polymer film is formed against said exposed cavity wall portions between said separated flange surfaces.

10. A method of manufacturing articles as described by claim 9 whereby independent film coated articles respective to said pair of shaped article blanks are obtained by trimming said continuous band of film between said opposing pair of flange surfaces.

11. A method of manufacturing articles as described by claim 9 whereby said continuous band of film between said opposing pair of flange surfaces is partially trimmed to leave a hinge portion of film connecting said pair of shaped article blanks.

12. A method of manufacturing articles as described by claim 9 whereby said continuous band of film between said opposing pair of flange surfaces is trimmed about the band perimeter thereof and subsequently fused along a perimeter increment to provide a hinge portion of film connecting said pair of shaped article blanks.