Container Closure

Abstract

A container closure is disclosed for a single service, or non-reuseable, container. In the preferred form of the invention the container has a pair of wall sections made of paper material and placed in side-by-side relationship, the outer surfaces of these wall sections being coated with polyethylene. A closure strip having its inner surface coated with polyethylene is bonded to both of the wall sections by application of suitable heat and pressure. The polyethylene coating on the inner surface of the closure strip is substantially thicker than the coating on the outer surfaces of the wall sections, hence the application of heat and pressure for bonding the coatings together also causes the coating of the closure strip to permeate much more deeply into the material of the closure strip and thereby become more securely bonded to the closure strip than the coatings of the wall sections are bonded to the wall sections. A pull tab on the closure strip is used to pull the strip, resulting in tearing of the coatings from the wall sections, so that the wall sections are no longer joined together.

Description

BACKGROUND OF THE INVENTION

Many containers are not designed to be reuseable, that is, the container is delivered to a customer containing a product which is typically a food product, and when the product has been entirely consumed then the container is thrown away. A typical example is a cardboard carton having the surface of the cardboard coated with a waxy material to render it impervious to the flow of liquid, the container being filled with milk or a soft drink. Some means is provided for opening the container in order to dispense its contents when and as required. When the contents have been consumed the container is thrown away.

In that type of container it is desirable that the opening through which the liquid contents are dispensed is capable of being re-closed, although it is not necessary that it be re-sealed. The opening must be closed in order to prevent dirt or other solid materials from falling into the container, but sealing is not necessary because the container is generally kept under refrigeration until the liquid contents thereof have been consumed.

In the foregoing application of disposable containers it is also desirable to be able to re-seal the opening of the container, but that is not an absolute requirement.

The primary object and purpose of the present invention is to provide a closure mechanism for a single service container, which is cheap and easy to manufacture and which is entirely reliable and satisfactory in its operation.

Another object of the invention is to provide a container closure which utilizes, in a new and different and more effective manner, the very same material from which the containers themselves have commonly been made heretofore.

SUMMARY OF THE INVENTION

According to the invention, a pair of wall sections of a container are joined and sealed by bonding a closure strip to the adjacent surfaces of both of the wall sections, and the closure strip is provided with a pull tab at one end thereof for tearing the closure strip from the wall sections so that the wall sections will then be no longer joined together. The tearing away of the closure strip results in a partial destruction of the wall sections of the container but that apparent disadvantage is more than offset by the cheap and easy nature of the manufacturing process as well as the easy and satisfactory manner in which the closure is opened.

More specifically, in its preferred form the invention contemplates the use of container walls made of a paper material, and having their exterior surfaces covered with a waxy coating material such as polyethylene, for rendering the walls impervious to the flow of liquid therethrough. The closure strip is securely bonded to the waxy coating of the container walls, and when the closure strip is pulled it tears off the coating portions which underlie the closure strip, so that the wall sections of the container are no longer joined together.

Still more specifically, the closure strip itself has a coating of waxy material such as polyethylene, and the coating on the closure strip is bonded to the closure strip more firmly than the coatings on the wall sections of the container are bonded to those wall sections. When the closure strip is pulled the weakest of the three bonds, that is the bond between the wall sections and the wall section coatings, is the one which is pulled loose.

According to the presently preferred form of the invention the coating on the closure strip is made thicker than the coatings on the container wall sections, as a means of creating a stronger bond between the closure strip and its coating. Application of heat and pressure in bonding the closure strip to the wall sections causes the coating material of the closure strip, by virtue of its greater thickness, to diffuse more deeply into the coating strip and thereby create a stronger bond. The chemical action between the two coatings is such that the bond between the two coatings is inherently stronger than the bond of a coating to a paper material.

According to another preferred feature of the invention the coatings on the wall sections of the container are scored along score lines located adjacent the edges of the closure strip. The result of this feature is that when the closure strip is pulled, the coatings of the container wall sections tear along the score lines.

DRAWING SUMMARY

FIG. 1 is a perspective view of a bipartite separable container provided in accordance with the invention;

FIG. 2 is a cross-sectional view taken on the line 2--2 of FIG. 1;

FIG. 3 is a cross-sectional view taken on the line 3--3 of FIG. 1;

FIG. 4 is a perspective view showing the closure strip being pulled from the container of FIG. 1;

FIG. 5 is a view like FIG. 2 but showing how the pulling of the closure strip causes a tearing of the wall section coatings;

FIG. 6 is a perspective view of the two separate halves of the container of FIG. 1 after they have become fully separated;

FIG. 7 is a perspective view of another type of container provided in accordance with the invention;

FIG. 8 is a cross-sectional view taken on the line 8--8 of FIG. 7;

FIG. 9 is a perspective view showing the closure strip being pulled from the container of FIG. 7; and

FIG. 10 is a perspective view of a third form of container provided in accordance with the invention.

EMBODIMENT OF FIGS. 1 TO 6

In FIGS. 1 to 6, inclusive, there is illustrated a bipartite separable container A which includes two separate open-topped rectangular cartons 10 and 11. The cartons 10 and 11 are disposed in aligned relationship with their open tops in mating engagement, and a closure strip 12 is bonded to the periphery of the tops of the two cartons for holding them together. Closure strip 12 has a pull tab portion 13 at one end thereof.

As best seen in FIG. 2 the carton 10 has a peripheral wall 15 on whose external surface there is a waxy coating 16. The carton 11 has a peripheral wall 20 on whose external surface there is a waxy coating 21. The mating edges of the walls 15, 20 are abutted together at 24. Closure strip 12 includes a paper-board strip 25 having a waxy coating 26 on its inner surface and a waxy coating 27 on its outer surface. The closure strip 12 is positioned symmetrically with respect to the cartons 10, 11, so that half of the closure strip overlies the wall 15 of carton 10 while the other half overlies the wall 20 of carton 11. Inner coating 26 of the closure strip 12 is securely bonded to the corresponding surface portions of the coating strips 16, 21, respectively. As also clearly shown in FIG. 2, the coating 16 is marked with a score line 17 located adjacent the corresponding edge of closure strip 12, and the coating 21 is marked with a score line 22 adjacent the corresponding edge of closure strip 12.

In the closure structure as shown in FIG. 2 the bond between coating 26 and paper-board strip 25 is stronger than the bond between coatings 16, 21, and their respective wall sections, and the bond between coating 26 and the coatings 16, 21 is also stronger than the bond between those latter coatings and their respective wall sections 15, 20.

In order to achieve the relative strengths of the bonds that is desired, the preferred construction is as follows. Coatings 16 and 21 are preferably made of polyethylene material having a thickness of about 2 mils. The coating 26 is preferably made of polystyrene material having a thickness of about 4 mils. Closure strip 12 is fastened to the cartons 10, 11 by the application of heat and pressure, and this process causes the material from the inner surface coating 26 to diffuse or permeate into the structure of paper-board 25 to a much greater extent than the material from coatings 16, 21 permeate into their respective wall sections. The bonding of the coating 26 to strip 25 is, therefore, stronger than the bondings of the other two coatings.

The coatings may be made of a substantially water insoluble material which is normally solid at room temperature and which adheres to paper products and fabrics. Suitable waxy materials include, for example, low molecular weight natural and synthetic polymeric materials such as polyethylene,polypropylene, natural resins, beeswax and the like.

FIG. 3 shows a detail of the wall construction of the carton 10. The paper-board wall is designated by numeral 18, a coating on the inner wall surface is designated as 18a, and a coating on the outer wall surface is designated as 18b. The paper-board wall 18 is typically of about 15 mils thickness, while the coatings 18a, 18b typically have a thickness of about 11/2 to 2 mils.

FIGS. 4 and 5 portray the operation of removing the closure strip 12. As the pull tab portion 13 is pulled away, the portion of the closure strip that is bonded to the surface coating 16, 21 commences to tear those coatings loose, as best seen in FIG. 5. Coatings 16, 21 are torn away along the score lines 17, 22, respectively.

Of course the container closure shown in FIGS. 1 to 6, inclusive, will operate very satisfactorily without the use of score lines 17, 22. The advantage of using the score lines, however, is that the closure will open in a predetermined manner, thus avoiding an appearance which might be considered unsightly, if the coatings were torn from the wall members 15, 20 in an irregular configuration.

When the closure strip 12 is removed in its entirety the two cartons 10, 11 become completely separated from each other, as shown in FIG. 6. Each of these cartons then provides a separate, independent, open-topped container. One application of these containers, for example, is for the delivery of milk cartons to schools. Each carton 10, 11 is filled with a quantity of individual milk cartons. The composite container A as shown in FIG. 1 is delivered in a fully sealed configuration. When closure strip 12 has been removed the cartons 10, 11 may then be transported individually.

Cut out handles in the end walls of the cartons are provided for convenience in handling. The cartons are rather inexpensive, and are of light weight, and after their initial useage they will ordinarily not be returned to the supplier from whence they came.

EMBODIMENT OF FIGS. 7 TO 9

Another embodiment of the invention is shown in FIGS. 7 to 9, inclusive. A container B has a wall member in which a generally U-shaped cut 29 is made, resulting in an opening flap 35 being formed within the U. Wall sections on the respective sides of the opening flap 35 are designated as 30, 31, respectively. A closure strip 32 lies over the opening flap 35 as well as the immediately adjoining portions of the wall sections 30, 31. Closure strip 32 has a pull tab portion 33 on one end thereof. As best seen in FIG. 8, wall section 30 has an exterior surface coating 41, and the pull tab 35 and wall section 31 have exterior coatings 46, 42, respectively. The entire upper wall of the container B is preferably formed as a single sheet member, hence the coatings 41, 46, 42 are preferably made of the same material having uniform thickness and characteristics throughout. Score lines 36, 37 in the coatings 41, 42 are provided adjacent the respective edges of the closure strip 32, in the same manner as described previously with reference to the first embodiment.

The closure strip 32 includes a paper-board member 43 having a coating 44 on its inner surface and a coating 45 on its outer surface. As before, the coating 44 is bonded more securely to the paper-board strip 43 than the coatings 41, 42 are bonded to their wall sections 30, 31, respectively. The bond between coating 44 and coating 41, 42 is also stronger than the bonding of those latter coatings to their respective wall sections. Therefore, when the pull tab portion 33 of closure strip 32 is pulled up, as shown in FIG. 9, the coatings 41, 42 will tear along the score lines 36, 37, respectively. Opening flap 35 moves with the closure strip 32, however, thus providing an opening for the container B.

In the container closure of FIGS. 7 to 9 the closure strip 32 is not torn away entirely, but only to the point where the opening flap 35 has become fully open. A portion of the liquid contents may be drawn from the container B, and then the closure strip 32 with accompanying flap 35 may be closed back to the original position, until it is again desired to draw more of the contents from the container. The re-closing of the flap 35 with closure strip 32 is generally satisfactory, even without re-sealing, as has been previously explained.

EMBODIMENT OF FIG. 10

FIG. 10 shows another form of container C provided in accordance with the invention. One wall of the container has a generally U-shaped cut 54 which is, more specifically, of such configuration as to provide an opening flap having the shape of a toilet seat. Closure strip 52 covers the opening flap and adjacent portions of the wall member, and has an opening tab 53 on one end thereof. The arrangement of exterior surface coatings on the opening flap and adjacent wall sections, and of an interior surface coating on the closure strip 52, is the same as described previously with reference to the embodiment of FIGS. 7 to 9.

ALTERNATIVE FORMS

According to one alternative form of the invention an aluminum closure strip may be utilized, having a relatively thick polyethylene coating over its surface, the polyethylene coating extending around the side edges as well as over the top and bottom of the aluminum strip. In this manner a tight securement of the polyethylene coating to the closure strip is obtained, and lifting of the closure strip will pull the coatings away from the exterior surfaces of the wall sections of the container and cause them to tear, in the same manner as explained previously.

While the invention has been described in considerable detail in order to comply with the patent laws requiring a full public disclosure of at least one of its forms, such detailed description is not intended in any way to limit the broad features of principles of the invention or the scope of patent monopoly to be granted.

Claims

What is claimed as new in support of Letters Patent is:

1. A container closure comprising

a pair of wall sections disposed in a common plane to form respective portions of a flat wall, each of said wall sections having a coating on its exterior surface,

an elongated closure strip having an inner surface with a coating thereon,

said closure strip having a portion of its length positioned in engagement with both of said wall sections and said coating on said inner surface of said closure strip being bonded to said coatings on said exterior surfaces of both of said wall sections,

said closure strip also having a pull tab portion that is not bonded to said wall sections,

the coating on said closure strip being more firmly secured to said closure strip than the coatings on said wall sections are secured to said wall sections, so that when said pull tab portion of said closure strip is grasped and pulled the coatings on said wall sections are torn away so that said wall sections are no longer joined together.

2. A container closure as claimed in claim 1 wherein said wall sections and said closure strip are made of a paper material, and each of said coatings is made of a chemical composition capable of being bonded to the paper material as well as to the other coating.

3. A container closure as claimed in claim 2 wherein said coatings are bonded to the paper material and to each other by the application of heat and pressure.

4. A container closure as claimed in claim 3 wherein the coating on said inner surface of said closure strip is substantially thicker than the coatings on the exterior surfaces of said wall sections, whereby the application of heat and pressure in the bonding of said closure strip to said wall sections causes a greater permeation of said closure strip coating into the material of said closure strip, thereby resulting in a stronger bond of said closure strip coating to said closure strip.

5. The container closure as claimed in claim 2 wherein said coatings are made of polyethylene.

6. A container closure as claimed in claim 1 which further includes an opening flap located between said wall sections and disposed in said common plane thereof, said opening flap also having a coating on its exterior surface, and said coating on said inner surface of said closure strip being bonded to said coating on the exterior surface of said opening flap; the operation being such that when said pull tab portion of said closure strip is pulled, said opening flap is pulled away from said wall sections to provide an opening to the container.

7. The container closure claimed in claim 6 wherein said wall sections and said opening flap constitute respective portions of a single sheet member, said opening flap being formed by means of an essentially U-shaped cut in said sheet member, said closure strip being bonded to the surface of said member around the entire periphery of said opening flap.

8. A container incorporating the container closure of claim 1, said container including a pair of open-topped rectangular cartons disposed in aligned relationship with their open tops in mating engagement, said closure strip of claim 1 being bonded to the peripheries of said open tops for holding them together.

9. A container closure as claimed in claim 1, wherein said coatings of said wall sections are scored along score lines located adjacent the edges of said closure strip, whereupon the pulling of the closure strip causes said wall section coatings to tear along the score lines.