US3140808A - Container - Google Patents

Description

July 14, 1964 W E TAYLOR 3,140,808

CONTAINER Filed June 10, 1965 BY @LLM/@Mm United States Patent Office @,lliii Patented July 14, 1954 3,140,808 CONTAINER William Edward Taylor, Fairfield, Conn., assigner to American Can Company, New York, N.Y., a corporation of New Jersey Filed June 10, 1963, Ser. No. 286,737 9 Claims. (Cl. 229-45) This invention relates to easy open libre-bodied containers wherein the opening is effected by tearing open a glued lap type side seam, and has particular reference to a container body wherein the adhesively secured surfaces of the lap seam area are covered with films having varying, predetermined rupturing characteristics to positively ldirect the tear into the fibres of the side seam underlap layer to thus insure that the tear ends cleanly at the side seam underlap edge without objectionable onion-skinning.

It is very desirable, from an economical and functional standpoint, to package products such as cakes of biscuit dough, frozen foods or the like, in easy open composite containers which include a tubular fibre body having metal end closures permanently secured thereto. In one container of this type, the side seam edges of the fibre body are joined in an adhesively secured lap side seam. In order to facilitate opening of the container, a flap or tab is provided at the terminal end of the overlap layer of the side seam. This tab extends along the entire length of the seam on the outside of the body so that it may be readily gripped and pulled to tear open the container at the seam.

In order to prevent inadvertant, premature opening of this type of seam, a relatively strong adhesive is used to provide the seam bond. Thus, when the tabs are pulled outwardly to break open the seam to open the containers, the tearing action does not take place in the adhesive layer. Instead, the tear is randomly directed into either the underlap or overlap of the lap seam. When it is directed into the underlap, it ends cleanly at the terminal edge of the underlap, and a satisfactory opening condi tion is obtained. However, when it is directed into the overlap, the tear extends past this terminal underlap edge and results in a partial delamination of the main body wall. This condition is known in the trade as onion- Skinning, and is undesirable, since it is unsightly, and results in an unsatisfactory opening operation.

The present invention contemplates the elimination of onion-Skinning by the utilization of body coatings or laminations having different tearing strengths, the weaker coating being disposed immediately inwardly of the side seam adhesive and the stronger coating being disposed immediately outwardly of the adhesive. As a result, the weaker coating ruptures when the pull tab is pulled, and the tear is consistently directed into the side seam underlap layer, thus insuring the complete elimination of onion-Skinning.

An object of the invention, therefore is the provision of an easy-open lap seam fibre body wherein coating films having different tearing strengths are utilized to direct the tear into the lap seam underlap layer.

Another object is the provision of such a fibre container body which is made from a blank which has these coating films pre-applied so that only the conventional seam forming operations are required when the blank is formed into the body.

A further object of the invention is the provision of such a body construction wherein the differences in the tearing strengths of the protective films is effected by varying the thicknesses of the film, by utilizing films having different tensile strengths, or by a combination of both.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, Vdiscloses a preferred embodiment thereof.

Referring to the drawings:

FIGURE 1 is a perspective View of a sealed composite container embodying the instant invention;

FIG. 2 is a plan view of a flat blank from which the body of the container illustrated in FIG. l is made, a central portion of the blank being broken away;

FIG. 3 is an enlarged fragmentary sectional view taken through the side seam of the container, the view being taken along a plane indicataed by the lines 3--3 in FIG. 1; and

FIG. 4 is a view similar to PEG. 3 showing how the tear is directed into the side seam underlap when the opening flap is pulled to open the container.

As a preferred and exemplary embodiment of the instant invention the drawings illustrate a composite container C which comprises a tubular libre body 10 formed of one or more layers 11 of fibrous stock and having sheet metal top and bottom closure members 12 formed from tin plate, aluminum or the like material which are secured to the body 10 in suitable end seams 13.

The fibre body 10 preferably is made from a one-piece flat blank 14 (FIG. 2) bent into tubular shape to produce a cylindrical body with its opposing marginal edge portions secured together by a suitable adhesive 15 (FIGS. 3 and 4) to produce a lap side seam 16 having an underlap 17 and overlap 18.

Prior to its being formed into the body 10, the flat blank 14 is protected on its inner and outer wall surfaces by suitable films 23, 24 of protective coating material to produce a body which is gasproof, moistureproof and greaseproof. In the illustrated form of the invention, the films 23, 24 are shown as being formed of aluminum alloy foil which is prelaminated to the bre body stock 11 in the usual manner, being preferably adhered thereto by a suitable adhesive (not shown). The outer film 24 may be suitably imprinted to form a label layer, while the inner film 23 forms a lining for the body 1t) which prevents leakage of its contents. If desired, the inner raw edge of the underlap 17 may be coated with a suitable wax, etc. (not shown) to shield the brous body stock edge from the container contents.

As clearly seen in FIG. 4, the films 23, 24 extend into the lap side seam 16 and are disposed on opposite sides of and adhered to the adhesive layer 15, the film 24 forming the outer face of the underlap 17 and the film 23 forming the inner face of the overlap 18. To permit easy opening of the container, it is provided with a pull tab 26 which is formed integral with and forms an extension of the overlap 18 and with a pair of circumferential lines of weakening 27, 28, such as score lines (see FIGS. l and 2) which extend from the side seam 16 almost completely around the body. The tab 26 preferably extends for substantially the full length of the side seam 16, so that when it is grasped and pulled radially outwardly, the side seam 16 is torn open and the body thereafter torn along the score lines 27, 23 to expose the contents (not shown).

In order to provide a strong side seam 16, the adhesive which forms the layer 15 is preferably selected so that it and the bonds which it forms with the lilms 23, 24 are stronger than the adjacent portions of the lap seam 16. As a result, the tear which results when the flap 26 is pulled does not take place in the adhesive layer 15, nor does it result in rupture of the bond between the films 23, 24 and the adhesive layer 15. Instead, the container is constructed to direct the tear into the fibre stock 11 of the underlap 17 so that the tear ends cleanly at the underlap edge 29, thus eliminating any possibility of onion-skinning, which would occur if the tear were directed into the iibre stock of the overlap 18.

In order to insure that the tear is thus directed into the underlap 17, the container is Constructed so that the pro tective film 24, which forms the outer layer of the underlap 17, is weaker and less resistant to rupture or tearing than is the protective film 23, which forms the inner layer of the overlap 18. Thus, when the flap is pulled, the film 24, being the weakest layer subjected to the pulling force, is the seam component which ruptures. The resultant rupture 27 occurs at the edge of the adhesive layer 15, adjacent the juncture of the fiap 26 and the overlap 18, as best seen in FIG. 4. As a result, the tearing action extends through the film 24 and into the fibre stock of the underlap 17 and thence circumferentially through the latter, asl seen in FIG. 4, until4 it reaches the underlap edge 29 Where it terminates cleanly.

In the instant container, the films 23, 24 are both formed of the same metallic foil, such as aluminum or aluminum alloy so that both have the same tensile strength. In order to insure that the film 24 ruptures during the opening operation, it is made thinner than the film 23 so that its resistance to tearing is less. In one suggested construction, the film 23 is made .0006 inch in thickness, while the film 24 is made .0003 inch thick. It will be understood that other methods may be used to provide a film 24 of lesser strength than the film 23. Thus, each of these films may be made of a different aluminum alloy which differ in tensile strength, the film 23 of course having the greater strength. In such event, the lm 24 may be of the same or lesser thickness than the film 23.

It Will also be realized that the invention is not limited to the use of metal foils for both the films 23, 24. If desired these films may be formed of suitable plastics, such as nylon, mylar, polyethylene, copolymers of vinyl chloride and vinyl acetate, etc., which may either be prelaminated to the fibre stock v11 as integral layers, as by a casting or extrusion process, or may be sprayed, roller coated, or otherwise deposited thereon, either with or without a solvent base, as required. As with the metallic foils, the dsired tearing characteristics of the films 23,24 may be obtained by varying the thicknesses of these films, by using lms having different tensile strengths, or by a combination of these properties, consideration also being given to the properties (such as water, grease and moisture proofness) necessary to the effective functioning of the films 23, 24 as container liners and labels. Generally speaking, when different materials are used, the plastics having the higher tensile strengths, such as mylar, will be particularly appropriate for the film 23, while the weaker films, such as polyethylene, are particularly appropriate for use as the film 24. It will also be realized that a construction where one film is plastic and the other a metallic foil will also provide a satisfactory combination, provided the film 24 be substantially less resistant to rupture than the film 23. In one such suggested combination, the film 24 comprises an aluminum or aluminum alloy foil label, while the liner film 24 comprises a tough plastic such as mylar or nylon.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction, and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A container comprising a tubular fibre body having an inside coating and an outside coating and having opposed marginal edge portions thereof overlapped and secured together to provide a lap side seam having an underlap and an overlap, and a pull tab extending from the overlap of said seam to facilitate opening the container, said inside coating being more resistant to rupture than said outside coating for producing a break in the outside coating on the underlap of said lap side seam and for directing the tear into the fibre stock of the underlap of the side seam following the break in said outside coating when said container is opened.

2. A container of the character defined in claim 1 wherein said inside coating and said outside coating are of different materials having substantially the same thickness.

3. A container of the character defined in claim 1 wherein said inside coating and said outside coating are of the same material having different thickness.

4. A container of the character defined in claim 1 wherein said inside coating and said outside coating are of different materials having different thickness.

5. A container comprising a tubular fibre body having an inside coating of a moisture impervious material and Van outside coating of a moisture impervious material,

said body having opposed marginal edge portions overlapped as an inner lap and an outer lap and adhesively secured together to provide a lap side seam, and a pull tab extending from said outer lap of said seam for pulling said laps apart to open said container, said inside coating material and said outside coating material having different tensile strengths and tear characteristics for controlling and confining a break in a predetermined coating material on one of said laps of said side seam and a tear in the fibre body covered by said predetermined coating material when said container is opened.

6. A container of the character defined in claim 5 wherein said inside and said outside coating materials are plastic films.

7. A container of the character defined in claim 6 wherein one of said coating materials is a plastic film and the other is a metallic film.

8. A container of the character defined in claim 5 wherein said inside and said outside coating materials are metallic films.

9. A container comprising a tubular fibre body having an inner layer of aluminum foil secured to the interior wall surface of said body and an outer layer of aluminum foil secured to the exterior wall surface of said body, said body having opposed marginal edge portions disposed in overlapping relation with the layers of aluminum foil therebetween as an inner lap and an outer lap and adhesively secured together to provide a lap side seam, and a pull tab extending from said outer lap of said Seam to open said container, said inner layer of aluminum foil having a greater thickness and strength than said outer layer of aluminum foil so that when said laps are pulled apart to open said container the outside layer of foil on Vsaid inner lap having the thinner and weaker layer will break first and will adhere to and be completely torn away with the outer lap as the fibrous material in the inner lap of said body is delaminated toward its terminal edge.

References Cited in the file of this patent UNITED STATES PATENTS l2,814,428 Magill Nov. 26, 1957

Claims (1)

1. A CONTAINER COMPRISING A TUBULAR FIBRE BODY HAVING AN INSIDE COATING AND AN OUTSIDE COATING AND HAVING OPPOSED MARGINAL EDGE PORTIONS THEREOF OVERLAPPED AND SECURED TOGETHER TO PROVIDE A LAP SIDE SEAM HAVING AN UNDERLAP AND AN OVERLAP, AND A PULL TAB EXTENDING FROM THE OVERLAP OF SAID SEAM TO FACILITATE OPENING THE CONTAINER, SAID INSIDE COATING BEING MORE RESISTANT TO RUPTURE THAN SAID OUTSIDE COATING FOR PRODUCING A BREAK IN THE

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