Patent GB-1427531-A (GB)
Title: Formation of laminated packaging blanks
IPC: B65D5/56
Filed: 1972-04-10
Abstract: 1427531 Cartons KEVOLOK CO Inc 9 April 1972 [10 April 1972 1 Aug 1972 4 Nov 1972] 16351/72 35779/72 and 50956/72 Heading B8P [Also in Divisions B4-B5] A method of forming blanks, each of which comprises a unitary substrate X, e.g. of cardboard or stiff paper, adhered by a heat-weakenable laminating wax, e.g. a microcrystalline wax blend to an essentially overall layer Y of heatsealable material, e.g. coated film, coated metal foil, coated paper or thermoplastic film, wherein the improvement comprises providing a continuous web of fibrous material substrate, removing selected areas 1 of the web to provide openings which register with at least one end or side sealing region in respect of each individual blank to be formed, using a heat-weakenable laminating wax having a melting temperature of between about 140 and about 190 F. to laminate a continuous web of a moistureresistant sheeting over one surface of the fibrous material substrate web including the openings, the sheet being heat-sealable to itself at a temperature above the melting temperature of the laminating wax, and thereafter forming at least two parallel rows of blanks along the length of the continuous web by completing cutting along the periphery of each individual blank to separate each blank from adjacent blanks in the same row and in adjacent rows, the combined substrate-sheeting blank being thus severed along paths which cut the sheeting at at least some of the openings, to form individual blanks each having at least one unsupported sheeting portion at an edge location along the profile thereof, which unsupported sheeting portion constitutes an end or side sealing region of the blank that is designed to be heat-sealed to another location on the blank in the formation of the blank into a container by the application of heat directly to the unsupported portion. The blank may be formed and sealed into a moistureresistant packaging by folding the blank so that the unsupported portion lies generally adjacent another part of the sheeting, directly heating the unsupported portion and sealing the heated portion to the other part of the sheeting by the application of pressure whilst simultaneously melting the wax by which the other part of the sheeting is adhered to the substrate to detach the same. In an alternative procedure, heat and pressure are applied directly to the unsupported portion while it is in contact with the other sheeting region to seal it thereto while simultaneously melting the wax by which the other sheeting region is adhered to the substrate and detaching same therefrom, and folding and sealing the detached substrate. In the embodiment shown in Figs. 1 and 2, fragments of what will become six blanks are shown, the end portions of the two blanks principally shown each including two gussets 3 and flap 4, an area 1 from which a portion of the substrate has been removed being common to both blanks, severance locations between the gusset 3 and flap 4 being shown as solid lines and fold lines as broken lines. During the first die-cutting stage, select perforating is effected on a continuous web of the substrate X and the substrate occupying area 1 is cut from the web prior to lamination with the sheeting Y, the first die-cutting stage optionally including other perforation in addition to removal of area 1, e.g. forming spaced cuts and slots, and usually including the formation of fold lines, e.g. creases or scores defining the body panels 32, 33, 34, 35 and panels 4, 3, 30, 31, 37, 38, 39 to be sealed to other parts of the carton, the blanks being formed by severance along the lines A, B and C, Fig. 3, shows an open-ended carton-formed from a blank according to the invention in which the unsupported sheeting sealing fin 2 is disposed immediately above portions of the panels that form the end closure, the supported edge margins of fin 2 being adhered to the gussets 3 and closure flap 4. When the gussets are outfolded (Fig. 3a), the fin 2 comes into contact with the opposed portions of the sheeting, heat sufficient to form the sealed fin and to separate the sheeting from the substrate at the areas 3, 4, 30, 31, 37, 38 is applied and the gussets are infolded (Fig. 3b) to form a fin sealed container lying wholly within the substrate areas of the carton when the gussets are fully infolded with flap 4 folded over and sealed. In an alternative embodiment described with. reference to Figs. 4 to 7 (not shown), the blank is formed into a tray-shaped container. In a further embodiment described with reference to Figs. 8 to 12 (not shown), a blank is formed into a container comprising a carton of the substrate within a hermetic overwrapping, e.g. of aluminium foil.