Method and blank for forming a package within a wrapping
United States Patent Silver METHOD AND BLANK FOR FORMING A PACKAGE WITHIN A WRAPPING [75] Inventor: Stanley M. Silver, London, England [73] Assignee: Paxall, Inc., Chicago, 111.  
  22 Filed: Dec. 18, 1972 [21] Appl. No.: 316,238  
 Paulsen 229/37 R 3,040,963 6/1962 Turpin 229/14 BL 3,152,694 10/1964 Nashed et al...... 206/632 3,191,845 6/1965 Wainberg 229/32 [451 Apr. 15, 1975 3,411.694 11/1968 Silver 229/37 R 3.560.223 2/1971 Turbak 99/109 3,572,576 3/1971 Foster 229/31 [57] ABSTRACT A method and blank for forming an overwrapped package that is impervious to atmospheric moisture and vapor. The package is formed from a blank having a substratum of relatively stiff package-forming material on the exterior of which is secured a protective sheeting of moisture impervious material that is secured to the substratum by an adhesive of low melting point that is likewise moisture impervious and may be delaminated from the substratum by the application of heat. The method includes the steps of delaminating areas of the blank, folding the substratum of the delaminated area away from the sheeting and then folding the delaminated sheeting against the exterior of an adjacent portion of the blank.  
 13 Claims, 10 Drawing Figures METHOD AND BLANK FOR FORMING A PACKAGE WITHIN A WRAPPING The present invention relates to a method of and blank for forming a package, such as a box or carton and, more particularly. to such a method and blank for forming such package that will maintain its contents hermetically sealed against environmental effects, such as moisture, odors or the like, and is a variation and extension of my invention described and claimed in my US. Pat. No. 3,411,694.  
  The invention of my said patent is concerned with boxes or cartons which form a barrier against leakage of their contents, both liquid and gaseous, to the exterior. The present invention is directed to the provision of a method and blank for forming packages which bar the penetration into their interior of atmospheric moisture or vapor that might adversely affect the contents of the package and its walls.  
  Heretofore, endeavor has been made to protect contents of packages against, and the weakening of its walls by, the effects of atmospheric moisture by an overwrap of a film or foil, either loose or tight. Many such overwraps, as heretofore used, do not form effective bars against moisture and vapor and, therefore, do not provide complete protection. Also, they require for their production the use of overwrapping machines that are capable of a rate of production greatly below that of the cartoning machines, such as carton erectors, fillers and sealers. Additionally, such overwraps required the use of amounts of film substantially greater in area than the exterior of the cartons enclosed within them and, when such film or foil is very thin, they presented difficulties in moving through the machine. Tight overwrapping is the chosen method when exacting package appearance is required. However, such tight overwrapping further lowers production speed because of the need for application of glue in the course of the process.  
  The present invention is directed to a system and blank for forming an overwrap type of package in which all of the foregoing shortcomings are eliminated.  
  It is, thus, one of the objects of the present invention to devise methods and provide blanks for forming packages of the overwrap type that are substantially hermetically sealed, to thoroughly protect the box or package contents and the package walls against atmospheric penetration, especially atmospheric moisture or vapor, and thus protect both the contents and the walls of the box or package from deleterious effects of such environmental elements.  
  It is also an object of the present invention to devise methods and provide blanks to form overwrap type of packages, of the character described, which may be produced at a rate of speed greatly in excess than possible with conventional overwrap type of packages.  
  It is another object of the present invention to devise methods and provide blanks for forming overwrap type of packages, of the character described, which are economical in the use of the overwrapping material and in which the overwrapping material is capable of receiving surface printing and decoration and which will remain on the package after it is opened.  
  Broadly stated, the present invention employs the basic phenomenon of membrane delamination which is described and utilized in my aforesaid patent for forming the packages of the invention.  
  More specifically stated. the present invention provides a method for forming an overwrap package having moisture-barrier characteristics from a blank that is struck from a sheet of delaminable material. Such material comprises a substratum, of conventional packaging material having a degree of porosity as paper board, stiff paper and the like, and a multi-ply covering sheeting which includes inner and outer heat sealable plies or coatings between which is adhesively held a ply of stiffening material such as metal foil paper or polypropylene film or the like; which sheeting is delaminably secured to the substratum by a moisture resistent, heatweakenable laminant, such as a micro-crystalline wax blend. The method of the invention includes the steps of delaminating at least one select area of the blank, such as the overlapping flaps of a carton before folding, under the influence of heat to strip the sheeting from the substratum, and thereafter folding the stripped substratum into one selected position, and adhering the stripped sheeting to the sheeting of another blank area of the package exterior, thereby forming a substantially hermetic sheeting to sheeting seal.  
  To that end, the stripped folded portions of the substratum may include foldable gussets connecting other foldable portions of the substratum, with the gussets having a portion of their delaminated sheeting cut away and removed.  
  Clearer and more specific details of the packages of the present invention and of the methods and blanks by and from which they may be formed, and their foregoing and other objects and advantages, will be more clearly understood from the accompanying drawings and from the description following. It is to be understood, however, that the embodiment of the invention shown in the drawing is intended to be only illustrative of the invention and not as limiting the same to the specific details shown.  
 In the drawings,  
  FIG. 1 is a plan view of one end ofa blank formed according to the present invention, nested with and abutting one end of a second blank which is shown in phantom;  
  FIGS. 1A, 1B, 1C and 1D show four typical forms of laminations from which the blank may be struck;  
  FIG. 2 shows, in perspective, one corner of the blank in a first step of formation into a package and an associated apparatus element for producing the formation step illustrated.  
  FIG. 3 shows, in perspective, the same corner of the blank of FIG. 2; at a later stage of formation;  
  FIG. 4 is an elevational view of one side wall of the package and an associated apparatus mandrel member used in the formation of the package;  
  FIG. 5 is an isometric view of an erected package prior to sealing; and  
  FIG. 6 is a top plan view of the package at a later stage of formation.  
  More specifically stated, FIGS. 1A to 1D, inclusive, show four typical forms of lamination from which blanks according to the present invention may be struck. In all four, folding box board, 1, is the preferred substratum and a micro-crystalline wax blend, 2, is the preferred heat weakenable laminant which releasably secures the barrier sheeting thereto.  
  FIG. IA illustrates a barrier sheeting which comprises a lamination of a first inner heat sealable sheet or film of polyethylene 3; a stiffening ply of metal foil,  
 such as aluminum foil sheet 4; and a further, outer polyethylene sheet, 30. FIG. 1B. shows a barrier sheeting which comprises a first inner sheet of polyethylene film, 3, a thin paper sheet, 5; an adhesive layer, 6, over paper sheet, 5; an aluminum foil sheet, 4; and an outer polyethylene sheet, 30.  
  FIG. 1C shows a barrier sheeting which comprises a first inner sheet of polyethylene film, 3; a polypropylene sheet, 7, above it; and a further polyethylene sheet, 30.  
  The barrier sheeting illustrated in FIG. 1D comprises a first inner sheet of polyethylene, 3; a thin paper sheet, 5; and a further polyethylene sheet, 30.  
  It may here be stated that many other overwrap sheeting combinations may be employed in which, for instance, heat sealable polyvinyl films may be substituted for polyethylene, as well as heat sealable lac quers. The particular package style described herein requires that the sheeting be thermoplastically adhesive on both sides, but it may be noted that such characteristic would not be required with other packaged styles if mandrel means could be employed to make pressure contact with all the plies to be fused together.  
  In FIG. 1, there is shown one end of a blank formed from a lamination, such as detailed above, a blank end being in substantially common, knife-nested relationship with the end of another blank which is shown in phantom. The other end of the blank, which is not shown, is identical to the end of the blank shown in phantom. The blank is creased and scored for folding into a carton or box to define the various panels and flaps forming the sides and ends of the package. All creases are indicated in the drawings by broken lines and all score lines, which cut through the sheeting, by unbroken lines. The arrow X indicates the preferred grain direction of both the substratum and sheeting; though in certain instances the grain direction could be at an angle of 90 to that indicated in the drawings.  
  The panels of the blank comprise a base, 8, a front side wall, 9, a rear side wall, 10, and a top, 11, and a tucking panel, 12. Connected to the base, 8, is a side panel, 13, which has connected thereto a sealing flap, 14.  
  Side panel, 13, is connected, at each end, to front and rear side walls, 9 and 10, respectively, by a preferably L-shaped gusset, 15. Each gusset, 15, is connected along one edge to adjacent side wall, 9 or 10, as the case may be, by a crease line, 17. Each gusset, 15, is connected by its other edge to side panel 13, at its inner end by a crease line, 18, and outwardly thereof by a score line, 16, which extends at its inner end diagonally across gusset, 15, and continues, thereafter, parallel to crease line, 17, to the free edge of the gusset, the score line, 16, extending through the sheeting ply.  
  Gusset, 15, is foldable on a fold line, 19, which is formed to bend in a direction opposite to fold lines, 17 and 18, along which it is foldable relative to adjacent wall, 9 and 10, and to side panel 13.  
  FIG. 2 illustrates the treatment of the gusset, 15, at a first stage of formation of the container and shows the portion of the sheeting overlying the gusset as having been rendered delaminable through the employment of local heat and the portion 20 thereof outwardly of scored line 16, as having been removed, to leave a completely denuded gusset area which is designated in the drawing by stippling. The remainder of the delaminated portion of the gusset sheeting curls away from the substratum of thc gusset. This is the result of the method utilized in the local heating of the gusset area which is effected by a block, 100, formed with a serrated gusset contacting surface.  
  The gusset contacting surface of block, 100, is preferably serrated and coated with an adhesion-repellent coating, such as the substance commonly and widely distributed under the trademark of Teflon.&#34;  
  Block 100, which is heated and overlies the entire area of gusset, 15, will cause ply, 2, of the blank, namely the micro-crystalline wax, to melt, thereby causing a delamination between the sheeting 3 and the substratum 1 of the gusset and at the same time will cause the portion of the sheeting outwardly of score lines, 17, to superficially adhere to the heated, serrated surface of the block, 100, as indicated at 20, from which it may be easily removed, by reason of the serrated surface of the block by a mating tool not shown. It should be noted that throughout the operation, when sufficient heat is applied to the gusset, the wax blend laminant, which melts at Fahrenheit, will, at a higher temperature, lose all of its tack strength and will become fluid and be absorbed in the porosity of the substratum board, so that the sheeting and the substratum become instantly and completely nonadhesively separated.  
  FIG. 3 illustrates a further stage in the formation of the container in which the substratum of the gusset, 15, is folded inwardly on fold line 19 as side panel, 13, and the adjacent front and rear side walls 9 and 10 are erected. The substratum of the gusset, 15, will fold inwardly by reason of the direction of creasing and the pressure applied at the time of erecting, and also by reason of the direction of the grain of the substratum. However, the remainder of the gusset sheeting which has been delaminated from its substratum and is some what curled away therefrom and which has its own stiffness and its own grain direction, will tend to remain static and foldable outwardly on crease 19, and will backfold 90 on crease 18, forming an exterior gusset which can be wiped and folded and adhered to side panel 13, with the outer portion of the gusset sheeting overlying the triangular portion, 23, of the sheeting lying between fold line, 19, therein, and crease line 18 (FIG. 4).  
  FIG. 4 shows the open topped tray immediately underlying a mandrel forming member 21, the cooperating female forming member of which is not shown. The mandrel reciprocates as the arrow indicates and is here shown removed from the tray subsequent to the folding of the sheeting gusset by 90, and adhering to the side panels 13. A portion of panel 13 has been torn away to reveal the interior of the tray; also shown is the substratum portion 22 of the gusset, disposed in the same direction within the pack as the gusset sheeting portion is outside.  
  The portion of the sheeting gusset that is backfolded by onto itself is defined by a dotted line and is marked 23.  
  In heat sealing the corner-staying gussets into position, the following stages are preferred:  
  Subsequent to heating the gusset and removing the scrap as shown in FIG. 2, and as quickly thereafter as is possible, mandrel 21 forces the blank through the cooperating female die member and other members, cooperate to shape the board and sheeting gussets as required. When all the pack corner members are positioned, intensive heat, preferably hot air. is locally applied to the surface of the sheeting gusset and the pack side wall with which it will be brought into pressure contact. When both surfaces have been sufficiently heated, the new adhesive surfaces may be brought into contact. In practice, it has been found that a wiping action applied to the sheeting gusset is preferred. Such wiping is best effected by a Teflon coated flat spring with a radius at the free end, such radius making initial contact along crease l7 and wiping across the whole of the sheeting gusset. As the mandrel is removed from the tray, the wipers return to their root position.  
  It should be noted that the sheeting is heat scalable on both sides, therefore an instant bond results from the combination of heat and pressure; it has been found that no pressure dwell-time is required.  
  FIG. 5 assists in the description of multiple stages of production. The tray is erected as shown in FIG. 4; the tray corners are securely adhered and the package ready for filling with product. It is to be presumed therefore that in FIG. 5 the pack would already contain product and is in one stage of being transported on a series of three endless conveyors.  
  The first direction of travel is indicated by a single arrow. In this direction the filled pack is transported by spaced pusher members, attached to an endless chain or the like. During transportation, panels 14 are splayed 90 outwards from their root position. This is simultaneous with panel 11 being back-folded 90 in relation to its root position. Panels 14 may now be brought into range of proximity heat introduced onto the sheeting surface. An alternative method is to bring panels 14 into contact with a serrated heated, Teflon coated roller. If a roller is employed, the sheeting, once in contact therewith, is pulled into an arcuate path. Hence it is necessary to employ a co-operating tool that is seated within the serrations and instantly strips the sheeting from the roller.  
  Immediately prior to stripping the sheeting from the roller, a blade-like tool may enter between the sheeting 14D and the substratum 14, thereby to effect positive separation therebetween. Immediately thereafter panel substrata 114 are folded inwardly by 90 from the root position. The pack in this condition is transferred onto a second conveyor, substantially as aforedescribed, whereupon panel 12 is delaminated in a manner similar to panels 14. Immediately thereafter, panel 11 is folded 90 in relation to panel 10, stripped substratum 12 is tucked to lie parallel with the interior of panel 9 and stripped sheeting 12D is disposed to lie parallel to the exterior of panel 9. Panel 9 and sheeting 12D may then be heated on those surfaces that will contact each other, and pressure is applied in the wiping manner described in FIG. 4.  
  It should now be understood why the preferred sheeting for the pack described herein has a heat scalable surface on both sides. It will be obvious that the fusing of sheeting ll2D to panel 9 does not permit the employment of a mandrel; therefore the pressure that can be applied is limited. As a consequence it becomes necessary to bring cohesive surfaces together. It would be impossible to adhere a non-adhesive surface to achieve the quality of adhesion that results from heat scalable coatings without considerable pressure.  
  The third and final sealing stage involves another change of direction as shown by the three-part arrow and once again adhesion is caused in the manner aforedescribed to seal sheeting 14D.  
  In FIG. 6 there is shown the pack condition immediately prior to the last stage described with reference to FIG. 5. At this stage margins of cover panel 11 and sheetings 14D are heated and folded to contact each other. It should be noted that some structural rigidity is contributed by denuded panels 14, both of which are seen through the torn away portions of cover 11. Also shown is the gusseted substratum 22.  
  The pack that has been described is ideally suited for the barrier protection requirements of dry hygroscopic products. If the interior of the pack is coated with a moisture resistant material, then the pack will be suitable for products containing high moisture or even a limited amount of free liquid. Once the pack is completely assembled, the wrapper is sealed hermetically with the sole exception of four corner pinholes that appear at the top of the pack. These are breaks in the continuity of the sheeting and are equal to the thickness of the substratum, this not being the case at any other pack seam, all of which are totally imperforate. It should be noted, however, that the pinholes in the cover sheeting are backed up by multiple plies of waxed board.  
  All my previous work on the subject of membrane delamination provided the opportunity to create separate shapes from unitary sheet material comprising a substratum and a delaminable sheeting adhered thereon, provided that the panel(s) that were to be delaminated were always defined by a fold line. Attachment between the delaminable panel and an opposed panel(s) was required before delamination could take place, such being required prior to altering of the geometry of the stripped board.  
  These stages in series imposed certain limitations on the number of geometric shapes that could be produced. The technique of scoring only a portion of the sheeting in relation to the total panel of which it is a part, makes it possible to create a broader range of three dimensional shapes. Simply stated, one can score only a select portion of a panel area, and by so doing make only a select area of the sheeting freeable. Packs employing this technique may be provided with fold lines suitable for the main pack configuration whilst select areas of the blank may be scored potentially to free the sheeting where required. The freeable sheeting may be cleanly released by the local application of heat. The board that is stripped of all or part of its sheeting may be positioned as required and the freed sheeting maintained in reserve to perform a later sealing function. It is apparent that this is readily accomplished without necessarily relying on the fold lines required for the formation of the substratum into pack form. The process technique aforedescribed is obviously applicable to many other pack styles.  
 What I claim is:  
  l. A method for forming an overwrapped package, of the character described, comprising the steps of forming a blank having foldable portions, said blank including a substratum formed of substantially stiff package forming material and a moisture resistant sheeting having self-adhering surfaces, delaminably secured to said substratum by a moisture resistant heat weakenable laminant, delaminating at least one foldable area of the blank under the influence of heat to strip the sheeting from the substratum thereof, folding said stripped substratum area to a selected position, away from its delaminated sheeting, and thereafter folding the stripped sheeting over and adhering it to the sheeting portion of another blank area on the exterior thereof. to thereby form a sheeting to sheeting seal between said stripped sheeting and said sheeting portion.  
  2. The method according to claim 1 wherein said sheeting to sheeting adhesion is effected by the application of heat.  
  3. The method of claim 1, wherein the substratum material is porous to at least partly absorb the laminant material upon the application of heat.  
  4. The method of claim 1 wherein said blank foldable area comprises a gussetted corner wall which interconnects adjacent wall panels and wherein a score line extends through said sheeting in the gussetted wall region and defines a detachable area so that, when said delaminating of said foldable area occurs, said detachable area of sheeting separates from the remainder of said delaminated sheeting.  
  5. A blank for forming an overwrapped package of the character described comprising a substratum ply of substantially stiff package forming material and a sheeting ply overlying said substratum and secured thereto by a moisture-resistant heat-weakenable laminant material, whereby said sheeting is delaminable from said substratum by the application of heat, said blank including wall panels pre-creased for folding away from a delaminated portion of said sheeting, at least one area of the sheeting on said blank being severed from the remainder thereof and detachable from the rest of said blank upon delamination.  
  6. The blank of claim 5, wherein said heatweakenable laminant material is of low melting point,  
 and wherein said substratum comprises porous fibrous material adapted to absorb the said heat-weakenablc laminant upon application of sufficient heat for melting the same.  
  7. The blank of claim-5, wherein said sheeting comprises heat-sealable inner and outer surfaces.  
  8. The blank of claim 5, wherein said sheeting comprises adhering multi-plies of material including inner and outer plies of heat-scalable film and an intermediate ply of stiffening material.  
  9. The blank of claim 8, wherein said inner and outer plies comprise polyethylene film.  
  10. The blank of claim 8 wherein said intermediate ply comprises a sheet of material selected from the group of paper, metal foil and polypropylene film.  
  11. The blank of claim 5 wherein said blank comprises a plurality of panels defined by fold lines and wherein said severed area is defined by a score line cut completely through said sheeting which crosses one fold line and which is spaced from another fold line for at least a portion of the length of said score line.  
  12. The blank of claim 5 wherein said substratum includes a base to which are hinged side panels and a front panel, said pre-creased wall panels being gussets hinged respectively to said front panel and to one of said side panels, each of said gussets including a diagonal crease extending outward from a corner of said base, said severed sheeting area overlying a portion of said gusset.  
  13. The blank of claim 12 wherein said area is severed along a line that is spaced from one of the lines along which said gusset is hinged to one of said panels and that crosses said diagonal crease.