US 3557947 A
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United States Patent  References Cited UNITED STATES PATENTS  Inventor Joseph D. Greenwell Wilmington, Del. 722,662
 Appl. No.  Filed 3,140,039 229/62 3,388,788 6/1968 Hellem..,................ 206/45 33 3,447,675 206/4533 Apr. 19, 1968 Patented Jan. 26, 1971 Assignee EJ-du pom De Nemours and Company 6/1969 Wilmington, Del. Primary ExaminerJames B. Marbert a corporation of Delaware. Attorneylvan G, Szanto  Z i Z CONTAINER PACKAGE ABSTRACT: A package of a plurality of cans arranged in adalms, 7 Drawing Figs.
jacent linear rows and overwrapped 1n a heat-shrunken tubu-  US. lar web of thermoplastic film having joined overlapping web layers on the top of the package with finger holes within the area of the joined overlapped web layers located above the void spaces formed within the can groupings.
206/65  Int. B65d 65/02  Field 206/65C,
45.33; 229/40, 62, 48T, SC, (Digest) PATENTEU JAN26 197i FIG-2' FIG-5 FIG-6b FIG-6(1 INVENTOR JOSEPH D. GREENWELL ATTORNEY MULTIPLE CONTAINER PACKAGE BACKGROUND OF THE INVENTION 1 Field of the Invention This invention is related to packaging and more particularly to the packaging of a plurality of cans in a heat-shrinkable, thermoplastic film overwrap.
2. Description of the Prior Art One of the most prevalent packages for canned beverages on the market today is the multipack type of package. This package usually comprises a grouping of from four to eight cans into a common assemblage. voluminous art exists relating to the designs of sixpack types of packages. One such design comprises the grouping of cans overvvrapped in a tubular web of heat shrunken thermoplastic film and has finger receiving holes in the overwrap located above the void areas formed by the groupings of four adjacent cans. This design of package generally requires a heavier gage web on the package top where the finger holes are located than is required for the achievement of sufficient strength on the package sides and bottom. In practice such overwraps commonly are formed of two webs which are side sealed together to form a tube prior to the heat shrinking of the overwrap. For example, a l mil thick web of heat shrinkable polyethylene is employed for use on the sides and the bottom of the package. and a I 1% mil thick web of heat shrinkable polyethylene is employed on the top, finger-hole side with both webs sealed one to the other to form a tube. This procedure insures a stronger web on the package top where most of the handling stresses on the overwrap take place but requires the use of the two webs of material to form the overwrap.
Another design of a similar type of package employs a tubular sleeve of heat shrinkable thermoplastic film on which is bonded a separate reinforcing strip in the area of the finger receiving holes. This package design provides for a strengthened top portion of the overwrap but also requires that a separate web be used in the fabrication of the package to achieve the reinforcement of the package's finger-hole area.
SUMMARY OF THE INVENTION According to the present invention there is provided in a package comprising a plurality of containers arranged in a substantial wall-abutting relationship with one another whereby void spaces are formed within container groupings and an overwrap of heat shrunken thermoplastic tubular film whose tubular axis is perpendicular to the direction of the axes of the containers, the overwrap arranged in a contour conforming configuration with the containers wherein the improved overwrap comprises:
a web of thermoplastic film formed into a sleeve,
a band on the top of the package formed by at least two overlapping layers of the web, the band having at least one finger hole substantially aligned with the void space formed within the container groupings, and
a bond between the two overlapping layers of the band.
The package of the present invention can be fabricated more readily than can the existing packages of comparable design since the only packaging material required is a single web of heat-shrinkable thermoplastic film. The cost of the packaging materials required is significantly lower than is the cost for existing packages of comparable design.
BRIEF DESCRIPTION OF THE DRAWINGS Reference to the following drawings will facilitate the understanding of this invention.
FIG. 2 is a fragmentary transverse sectional view of the overwrap of the package taken across one of the finger holes of the package of FIG. I at Section 2-2.
FIG. 3 is a fragmentary transverse sectional view of another embodiment of the overwrap of the package taken across one of the finger holes otthe package.
FIG. 4 is a fragmentary transverse sectional view of still another embodiment of the overwrap of the package taken across one of the finger holes of the package.
FIG. 5 is a schematic illustration ofa three layered reinforcing band.
FIG. 6a and 6b are schematic illustrationsof four layered reinforcing bands.
DESCRIPTION OF THE PREFERRED EMBODIMENTS The package shown in FIG. I comprises a grouping of cans I and a thermoplastic, heat'shrinkable overwrap 2. The cans I may have cylindrical walls, as shown, or flat walls forming a polyhedron. The construction of the cans I can be of the three-piece type or of the two-piece type having an upper recessed chime. The cans 1 can be fabricated from metal. paper or combinations of metal and paper products. The only limitation in reference to the cans used in the package of this invention is in their arrangement. The cans are arranged as shown in FIG. I with their axes parallel with one another and arranged in abutting linear groups so that void spaces are formed within the grouping of any four grouped cans. Groups of eg four, six, eight or more cans so arranged can be accommodated by the package of the present invention. In the preferred embodiment the overwrap 2 is a 1% mil heatshrinkable polyethylene web such as 240 EH Clysan' (produced by E. l. du Pont de Nemours and Co.). This particular film is a balanced. biaxially oriented. heat-shrinkable polyethylene but the practice of this invention is equally accomplished using uniaxially oriented film with the stretch axis running normal to the flow path of the cans being overwrapped. Other types of heat-shrinkable films useful in forming the package shown in FIG. I are those manufactured by commercial methods from polymers such as polypropylene, polyvinyl chloride, polyethylene terephthalate and polystyrene. The heat-shrinkable web employed must have sufficient shrinkage capability to tightly envelop the grouping of cans into a rigid structure that can be handled conveniently. Thus, the required degree of orientation of the film employed for the overwrap 2 is dependent on the configuration of the cans l and the type of apparatus used to fabricate the package.
The overwrap 2 is formed from a single web of film. It preferably is formed into a tubular sleeve by overlapping the edges 2a and 2b of the web on the top of the package being formed and sealing the overlapped web layers by use of a single or preferably parallel, double, continuous seals 3 and 4 which are separated from each other to form a band 5 comprising two layers of the web used to form the overwrap 2. To obtain additional reinforcement the edges can be folded a number of times yielding e.g. three or four overlapped film layers, as shown on FIG. 5 (2g, 2g, 21, 21'), respectively. Finger holes 6 and 7 as shown in FIG. I are melted into the band 5 directly above the void spaces formed within the grouping of any four grouped cans. It is preferred that these holes be formed by a shaped heated element so that a polymeric bead is formed around the periphery of each hole for reinforcement of the overwrap 2 at each finger hole.
FIG. 2 shows a fragmentary transverse sectional view of the overwrap 2 taken across Section 2-2 of FIG. 1 to further illustrate the structure of the reinforced finger holes. The overlapping edges 20 and 2b of the overwrap 2 are sealed by heat or adhesive seals 3 and 4 to form the band 5 shown in FIG. 1. Finger hole 6 is formed in the double layered band 5 between seals 3 and 4. A reinforcing finger hole bead 8 bounds the finger hole 6 and joins the two layers of the web in this region. It is not necessary that a finger hole be formed in the overwrap above each void space within every grouping of four cans since the provision of one finger hole per package provides an adequate carrying means for the package. In the use of a single finger hole the person handling the package uses the one finger hole while placing his thumb in the region 9, shown in FIG. I, of the overwrap. Six-pack and eight-pack packages can be carried comfortably in this manner for extended periods of time.
H68. 3 and 4 show fragmentary sectional views of other embodiments of the overwrap taken across a finger hole to illustrate the structure of the overlapped web layers adjacent to the reinforced finger holes. ln FIG. 3 the overlapping web layers 20 and 2d are bonded together in the wide seal area and the finger hole 60 lies within the seal area 10 of the bonded web layers and 2d. The web layers 2c and M can be bonded by use of a heated laminating roll similar to the rolls employed to form the heat seals 3 and 4 shown in FIGv 2. The web layers 2c and 2d can also be adhesively bonded e.g. by applying a vinyl acetate copolymer or latex adhesive between the web layers prior to the passage of the overlapping web layers through a laminating device.
In the embodiment shown in H6. 4 the web layers 22 and 2f are joined together by a series of heat seals such as seals ll, 12, 13 and 14. These seals can be continuous as are those shown in FIG. 1 or they can be discontinuous. Sealed areas such as obtained by use of heated knurled rolls or of heated waffle-grid surfaced rolls also provide joined web layers of this same type wherein the web layers are joined in a bonded pattern as determined by the surface of the heated sealing roll employed to effect the seal between the web layers.
In the commercial production of the packages of this invention the heat-shrinkable, thermoplastic web is fed from a continuous length supply roll into a tube forming section where the tubular sleeve is formed around preselected groups of containers. The two top seals are made as the sleeve is closed around the container groupings. The desired number of finger holes are then melted through the double-web layer on top of the container groupings. After the thermoplastic sleeve is formed around the groupings of containers it is severed between groupings to permit an excess of the prefonned sleeve to extend beyond the longitudinal confines of the individual container groupings.
Each package consisting of the grouped containers and the surrounding thermoplastic sleeve is then passed through a heat shrinking chamber. Typical heat shrinking temperatures employed while packaging at the rate of l20 packages per minute using 240 EH Clysan' film (heat shrinkable polyethylene produced by E. l. du Pont dc Nemours and Co.) were 330 F. for preshrinking and 280 F. for total shrinking. The overwrap during this operation shrinks in all directions yielding a package as shown in FIG. 1. The shrinking forces exerted by the thermoplastic film causes the overwrap to tightly enclose the containers on six sides so that relative container-to-container movement is restricted under normal handling conditions. The heat required to shrink the overwrap is normally transmitted by use of circulated hot air currents or by radiant heat transfer such as emitted from infrared light sources or from electrically energized resistance heating ele ments.
1. In a package comprising a plurality of containers arranged in a substantial wall-abutting relationship with one another whereby void spaces are formed within container groupings and an overwrap of heat shrunken thermoplastic tubular film whose tubular axis is perpendicular to the direction of the axes of the containers, said overwrap arranged in a contour conforming configuration with the containers wherein the improved overwrap comprises:
a web of thermoplastic film formed into a sleeve;
a hand on the top of the package formed by at least two overlapping layers of said web. said band having at least one finger hole substantially aligned with the void space formed within the container groupings; and
a bond between the overlapping layers of said band.
2. The package of claim 1 wherein said band comprises three overlapping layers of said web.
3. The package of claim 1 wherein said band compriscs four overlapping layers of said web.
4. The package of claim 1 wherein said bond is a layer of adhesive.
5. The package of claim 1 wherein said bond is a heat seal bond.
6. The package of claim I wherein said bond consists of at least two heat seal joints substantiallyparallel to the axis of said sleeve.
7. The package of claim 1 wherein said bond consists of two continuous linear heai seal joints substantially parallel to the axis of said sleeve.
8. The package of claim 1 wherein the thermoplastic film is heat-shrinkable polyethylene.
' .9. The package of claim 1 wherein the containers are arranged in two abutting rows.
10. A package comprising a grouping of cans arranged in two adjacent linear rows each consisting of at least two cans and an overwrap formed from a web of thermoplastic film enclosing said grouping 'of cans, said web being formed into a tubular sleeve whose tubular axis is perpendicular to the direction of the axes of the cans and said web having its overlapping edges sealed together to form a band comprising at least two layers of film, said cans being arranged in abutting relationship with each other and forming a void space within a grouping of any four grouped cans and said band being positioned between said rows of cans and having means defining at least one finger hole therein substantially aligned with a said void space within a said grouping of four grouped cans.