US3334799A - Container top closure construction - Google Patents

Description

Aug 8 1967 D. J. CRAWFORD l 3,334,799

CONTAINER TOP CLOSURE CONSTRUCTION Filed Aug. 19, 1966 ATTORNEY United States Patent O 3,334,799 CONTAINER TOP CLOSURE CONSTRUCTION Duncan J. Crawford, Franklin, Mich., assgnor to Ex-Cell-O Corporation Filed Aug. 19, 1966, Ser. No. 573,535 1 Claim. (Cl. 229-17) ABSTRACT OF THE DISCLOSURE A liquid-tight extensible pouring spout for a large sized gable-top container formed of paperboard having an overall surface of heat scalable thermoplastic material with an abhesive sealing resistant coating applied over the surface adjacent the lip of pouring spout such that the abhesive coating is spaced from the lip of the spout a predetermined amount to define a marginal lip sealing area when the pouring spout is pressure heat sealed.

The present invention relates to packaging and more specifically to a container top closure construction. The invention finds particular, but not exclusive, utility in disposable containers adapted for uid packaging, milk, orange juice, concentrated syrups and other products.

One form of container of the type just noted and presently in wide commercial use, is disclosed in U.S. Patent 3,116,002, issued Dec. 31, 1963, to D. I. Crawford and V. Arslanian. Such a container is customarily erected from a at blank formed of sheet stock, such a paperboard having -an overall coating of thermoplastic film, such as polyethylene applied on the surfaces of the sheet. The blank has been cut to shape and impressed with an appropriate pattern of score lines which define a plurality of side panels, together with corresponding upper and lower extensions of flaps or closure members.

The container having a sealed closure of the type referred to in the above patent was designed for use in packaging fluids, such as milk and other dairy products. When a carton of this type is used to package concentrated syrups and other food products having a longer shelf life, the necessity of providing an improved closure seal is encountered to eliminate so-called top leakers. Although the sealed top closure of the type disclosed in the patent 3,116,002 have been commercially successful, they do possess critical areas for the developing of incipient fluid escape channels. It has been discovered that with the increase in size of the container, such -as the gallon container, the diiculty in sealing the escape channels is due to the heavier caliper paperboard. The increased amount of material in the larger size containers makes the control of the folding and sealing operation more difcult with the increased possibility of resulting fluid escape channels.

It is an object of this invention to provide a new and improved sealed gable top closure which can easily be released and extended by the consumer.

Another object of the present invention is to provide a container of the above characteristics which includes a sanitary extensible pouring spout having Ia line seal at the pouring lip edge.

A further object of the present invention is to provide an improved sealed container closure for large sized plastic coated paperboard containers which can be heat sealed over a pair of continuous offset parallel surfaces to eliminate incipient huid escape channels, While elimi- V nating the problem of effecting a continuous seal at their transition area, yet can be easily released while leaving the pouring lip area in a serviceable condition.

FIG. 1 shows an illustrative container having an enclosed pouring spout to which the present invention has been applied.

3,334,799 Patented Aug. 8, 1967 lCC FIG. 2 illustrates a container of the type shown in FIG. 1 with the pouring spout opened and the pouring p in position for dispensing the container contents.

FIG. 3 is a layout view of an inside surface of a container blank, with the side panels broken away, showing the inventive structure.

FIG. 4 is a cross-section View through the container rib and the upper portion of the pouring spout structure shown in FIG. 1.

One container of the type with which the present invention finds particular, but not necessarily exclusive utility, is shown in the accompanying drawings. Such a container is also disclosed in considerably greater detail in copending Egleston and Monroe U.S. Patent 3,270,940, issued Sept. 6, 1966. For purposes of the present invention, however, it will suffice to note that such container may `be formed from paperboard or other appropriate foldable sheet material and is self-sustaining in shape. The sheet material is rendered liquid-tight as by means of an overall coating, on both surface, of a thermoplastic material such as polyethylene, making the container capable of holding such acidic liquids as milk. This thermoplastic coating also serves as a heat sensitive adhesive of which overlapping layers of the sheet material may be sealed together when erecting and sealing the container. The coating adheres tightly to the paperboard so that it, as Well as any seals utilizing the coating, remains permanent and liquid-tight.

Referring more specifically to FIG. l, there is shown an illustrative container C, with its pouring spout extended, of the character set forth above and formed of plastic coated paperboard. The container comprises a tubular body 20 of generally rectangular cross-section having a dat bottom closure (not shown), and a top closure 22, which will Ibe Irecognized as the familiar gable top closure characterized by inclined roof panels 24, 25, surmounted by an upstanding central sealing rib or truss 26. In the present instance, the paperboard from 'which the container is formed is preferably a laminated blank of the type disclosed in 'US. Patent 3,239,126, issued Mar. 8, 1966, and assigned to the assignees of the present application. Typical dimensional figures designating the thickness of the outer layer which is in use in a onegallon container range from .0005 inch to .0004 inch of polyethylene. The paperboard material which is used as the main material of the container ranges from .017 inch to .030 inch. The inside coating of the container preferably comprises a laminate coating consisting of an adhesive layer 4ranging from .00030 inch to .00050 inch, an aluminum foil layer of approximately .00035 inch and a product contacting layer of polyethylene having -a thickness in the range of .00075 inch to .0010 inch.

The gable top closure is formed by the inclined roof panels 24, 25 each of which is surmounted by an outer.

sealing rib panel 29, 30 together with a pair of irl-turned triangular end panels 31, 32 each joined to the adjacent roof panels 24, 25 by triangular fold-back panels, 34, 35 and 36, 37 respectively. A side seam flap 38 is provided at one edge of the blank for the container C, for joinder with roof panel 24 and its associated side and bottom panels, to complete the body of the container. To complete the rib portion, each of the triangular fold-back panels includes adjacent its upper edge a corresponding one of inner rib panels 39, 40, 41, 42. These panels are shown more clearly in FIGURE 3 which illustrates a layout of the inside surface of a blank adapted to be erected into the completed container and closure of FIG- URE 1. When a container is erected from such a blank, the side seam ap38 is rst attached to the opposite edge portion of the blank to produce a flat-folded tube. This ilat folded tubular blank may be erected in any manner known in the art to form a container and closure.

. located on the pouring lip edge 4heat is applied to the thermoplastic coating on the various rib panels justrbefore the container is closed, after which a sealing pressure is applied to the sealing rib or truss 29, 30 thus formed by the various rib panels so that the hot plastic on contacting the lrib surface fuses to form a liquid tightV sanitary seal.

In order to dispense the contents of the container C, a suitable opening or spout is accessibly provided as a part of theclosure. In the case of the gable top closure as shown in FIGURE 1, one end of the closure is adapted to be pulled out to form a pouring spout -as shown in FIGURE 2. The steps of opening the spout are well known and are shown and described in my U.S. Patent 3,116,002. When the closure is heated `and subjectedgto pressure to effect a seal and thereby provide a sanitary package, all of the rib panels are subjected to heat at a temperature suiiiciently high to render the thermoplastic coating on the container moltenor tacky soV as to effect a liquid tight seal when the container closure elements are pressed together. As explained in Patent 3,116,002, a heat andA sealing resistant material which may, for example, be of the organo-siloxane type, is placed on the inner surface of the blank as shown as the shaded areas 46, 47 and 48 in the drawings, where it is desired to avoid permanent sealing.

As shown on FIGURE 3, the abhesive layers are printed or otherwise applied on each of the inner rib panels `39, 40 extending from a line 49, located a fraction of an inch below and parallel to the pouring edge 50. The abhesive extends downwardly and somewhat below the transverse score line 51,. By dropping theV printed layer 46 a small amount, as i approximately %4 inch on the blank used to form the onegallon size container, a marginal sealing area 52 of untreated material is retained on the surface of the blank. Also the abhesive layer 46 on each of the inner rib panels 39, 40 terminate short of the outer end thereof, as disclosed in our issued Patent 3,116,002, leaving at the 1 outer end of each such rib panel the sealing areas 53 of untreatedmate-rial on the surface of the blank.

It can thus be seen that in order to seal the pouring "spout ofr the instant invention itis only necessary to apply` pressure to the outer rib panels 29, 30 and inY turn to Vthe inner rib panels 39, 40 and 41, 42. However, it is not essential that the upper rib panels 54, 55 be heat sealed along their entire length to effectuate a fluid tight seal of the closure. As explained previously when the abhesive layer extended completely to the pouring edge 50 it was essential that a coextensive heat seal be attained between the upper rib panel` 54, 55. With the employment of heavier -gage paperboard the difiiculty of preventing an escape channel to form along the mating edge 50 is increasingly difiicult. This is due to the larger radius of curvature indicated at the transition area 56 in FIG- URE 4 caused by the transition from the four ply area Vof the container rib to the two ply area formed by panel 54, 55. By virtue of applicants invention it is now only required to engage and heat pressure seal the opposed co-planar surfaces 29, 30 to liquid seal the pouring spout along heat seal 57 while attaining a seal along the upper and outer extremities of panel 54, 55 to sanitarily protect the pouring spout. p

In order to insure that the channel 58 is completely closed to the passage of liquids of low viscosity it may additionally be required to provide tufts 59, 60 that are 50 adjacent the vertical fold lines 61, 62 of the container blank. It will be noted that tufts 59, 60, which are formed as integral continuations of the sheet material, are spaced equidistant from the scores 61, 62 suchY that upon formation of the conor example a distance of Y tainer they will be positioned in opposed relation near the outer extremity of rib 26. It can be seen from FIGURE 4 that the height of tufts 59, 60 are sufficient such that upon the formation of heat seal 63 the tufts will be crowded together under substantial compression in both a vertical and horizontal direction to completely block channel 58. In this-regard it should also be noted that the length tufts 59, 60 is limited to a distance in the order of one twentieth the total length of their associated edges 50. This is to prevent the accumulation of too great an amount of blocking material withinrchannel 58 such that the folding and sealing operation of the container packaging machines is disrupted.`

The cross-section View of FIGURE 4 also shows the inner surfaces of panel 39, 40Y provided with a pressure heat-seal 64 located in the vertical plane of pressure heat-seal 63. It will be noted that U.S. VPatent 3,116,022 shows this portion of lrib panels 39, 40 provided with a coating of rabhesive material to prevent the bonding of the juxtaposed surfaces of panels 39, 40. However, in the instant closure these surfaces, as indicated in FIGURE 2, are not coated with abhesive material with the resultant formation of the pressure heat-seal 64.

By virtue of the upward movement of the fold-back panel 34, 35 during the container opening sequence the seal 64 is initially broken prior to the seal 63. It was discovered that this sequential operationy made it possible to eliminate the abhesive coating on the juxtaposed surfaces of panel 39, 40 without interferring with the easy release characteristics of the closure.

While it will be apparent that thepreferred embodi- Vment of the invention therein disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation,

and change without departing from the proper scope orV board of thickness the order of .024 inch having arpolyethylene coating covering each surface thereof and comprising a tubular body having a bottom closure thereon, a pair of opposed roof panels inclined toward each other and overlying said body, a pair of opposed triangular end panels infolded between saidroof panels from the opposite gable ends formed by the latter, two pairs of triangular fold-back panels each pair of which is integral with a yrespective one of said infolded triangular end panels along fold lines which are substantially with said roof panels, said fold-back panels being folded against the undersides of said roof panels, a pair of side rib panels each integral with and surmounting a respective roof panel, two pairs of end rib panels, each end rib panel being integral with and surmounting a respective fold-back panel, the end rib panels of each pair being folded to lie against each other and to lie against the inner surface of a respective side rib panel, the Vheight of said end rib panels being less than the height ofsaid rib panels, said rib panels defining a central laminar top'rib divided longitudinally into a fixed portion and a movable portion, a sanitarily protected extensible pouring spout panels, said rib panels being adapted to be sealed together to form a liquid-tight seal by the Vapplication of heat and pressure thereto to bond together the contactingY polyethylene coated surfaces thereto, the improvement in the liquid-tight seal therein comprising: Y

(a) an abhesive coating covering a substantially rec-f tangular first strip portion on the inner surface areas of said adjacent pair of end rib panels, (b) said first strip portion extending parallel to and spaced from the upper free edges of said pair of end in contact 5 5 rib panels a distance of the order of %4 inch, said References Cited PXDDTSD SIICS] UNTTED STATES PATENTS panels, said last named strip portions being 1ocated 3,270,940 9/1966 Egleston et 'al 229" 17 the upper boundary of said irst strip portion to coincide therewith to provide a marginal 1iquidtight m JOSEPH R' LECLAI'R P' muy Emmmer releasable pressure heat seal having a ratio of length DAVID M. BOCKENEK, Examiner.

to width of the order of 30:1 to permit ease 0f opening upon formation of the container.

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