BACKGROUND AND SUMMARY OF THE INVENTION:

The present invention is generally related to containers for various products such as foods,

chemicals, drugs, powders, liquids and particulates, and more particularly, to a container including

a closure apparatus for sealing the container, using an induction heatable sealant.

Paperboard containers are known in the art. The present invention is concerned with

unique closure of containers and means by which opening of the container may be accomplished.

The present invention is concerned with providing a high quality cover or lid for paperboard

containers, which will enable ease of pouring of the contents from the container and/or ease of access to the contents, without sacrificing containment of the contents during periods of non-use. The present invention is not concerned with aerosol packages.

With popularity of microwave ovens, it is beneficial to have a container, designed to

accommodate foods, for example, which can be microwaved to heat the food contents without

removing the food from the container. One of the factors preventing the microwaving of some containers is that they include aluminum foil among the composite layers of paperboard which form the walls of such containers. Since metals cannot be microwaved, paperboard containers

having aluminum foil content are not suitable for microwaving. Recent innovation has allowed

for the removal of aluminum foil from paperboard containers. Another feature of the present

invention is that it will not exhibit undesirable reaction in response to microwave radiation.

In the case of foods in a paperboard container, it is desirable for the hd of the container

to accommodate pouring and/or access to the food from the container. The hd or opening should

be designed to maintain the hermetic nature of the container for aseptic packaging applications.

One of the important elements of any opening for a shelf-stable food package is the manner in

which the feature connects to and seals onto the body or wall of the container. The seals preferably ήjMπt the outside air from entering the package.

The present invention is designed to accomplish the aforementioned objectives. The present invention includes a lid and opening feature for a paperboard container. The present invention is designed to enable the container to be microwaved. The present invention comprises

a plastic frame having a channel therein, the channel being adapted to receive the leading edge of

a paperboard container. The channel is preferably filled with a sealant material. The leading edge of the paperboard container resides in the channel amidst the sealant material and may be induction welded in place to form a bond between the frame, sealant material, and leading edge of the paperboard container, adequate for the formation ofa seal of hermetic quality. The frame

may comprise a number of different embodiments to accomplish pouring of the contents from the container. In one embodiment the interior of the frame may be a plastic thermoformed insert having a pop-up lid. In another embodiment the frame may have a removable flexible or semi¬ rigid seal secured to the frame to cover the opening defined by the frame. In yet another embodiment, the frame may have a paperboard insert covering the opening defined by the frame. Combinations of these materials may also be used in association with the frame to cover the opening defined by the frame.

The invention will be described in greater detail in the following drawings and detailed description ofa preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view ofa paperboard container of the present invention;

Figure 2A-E shows a dkgrammatical view of the steps ofa preferred manner of assembly of the closure of the present invention having a thermoformed insert lid;

Figure 3A-E shows a ά^grammatical view of the steps ofa preferred manner of assembly

of the closure of the present invention having a paperboard plastic or combination thereof insert

hd;

Figure 4 is a plan view of the frame of the present invention;

Figure 5 shows a dkgrarmnatical overview of a preferred preparation of packages

incorporating the present invention;

Figure 6 is a sectional view of another embodiment ofa package closure apparatus of the present invention;

Figure 7 is a sectional view of another embodiment ofa package closure apparatus of the

present invention; and

Figure 8 shows a package filling assembly for use with the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the drawings, and particularly Figure 1, there is shown a paperboard

container 10 including the present invention. The container 10 is comprised of a paperboard kminate structure which forms the walls 12 of the container. The opening 14 for the container

is defined by a cover 16. Any one of several different materials (as described in greater detail

below) may be used to seal the open area defined by the cover 16.

Referring now to Figure 2A, a cross-sectional view of the cover 16 is shown. The cover

16 may be of a unitary construction, such as a thermoformed or injection molded plastic. A

channel 18 is formed in the cover 16 at its outer edge. Figure 2B shows an insert 20 in an

opening 14 of the cover 16. The insert 20 would be in the closed position (not shown) while the

product is on store shelves. For pouring contents of the container, the insert 20 may be opened

as shown in Figure 2B. The insert 20 may be comprised of a plastic material, a paperboard

irjaterial, a flexible material, other suitable materials, and combinations thereof Furthermore, the insert material may be entirely removed, as in the case with plastic or foil based peel-off

membranes (prior to use in a microwave), or it may have a hinged opening feature such as shown

in Figure 2B.

Figure 2C shows the introduction ofa sealant material 22 or coupling agent inside the channel 18 formed in the cover 16. The sealant material may be an adhesive polymer containing carbon or a metal such as iron, steel or other. To enable the container to be microwaved, the metal content in the adhesive polymer is preferably held to a minimum content to allow for

induction heating but not so great as to interfere with the microwave process.

Figure 2D shows the leading edge 24 of the paperboard container 10 about to come into contact with the adhesive polymer 22 within the channel 18. Figure 2E shows the leading edge 24 of the paperboard in contact with the adhesive polymer 22. At this point the induction heating process (also known as induction weldiαg to those of ordinary skill in the art) is used to melt the excitable material characteristics of the adhesive polymer which acts to bond the paperboard leading edge 24 within the channel 18 to form a hermetic seal. In addition to preferably preventing outside bacterial contaminants from entering the container around the sealed edge, the seal must also prevent leakage of the contents from the package. Between the steps shown in Figure 2D and 2E the content is placed into the container and as shown in Figure 2E, the insert is closed.

Figures 3A-E reveal much the same steps as shown in Figures 2A-E, except Figure 2A-E is for an insert made of paperboard. A frame 26 is shown in Figure 3A. A separate member 28

is secured to the frame 26 as shown in Figure 3B. The frame is preferably made from plastic material, while the member 28 may be of plastic, paperboard, or other suitable materials, or combinations thereof The renaming steps shown in Figures 3C-E are generally the same as

described with respect to Figures 2C-E. In a preferred embodiment of the present invention, the cover 16 and frame 26 as shown in Figures 2A and 3A respectively, include a guiding edge 30 for assisting the leading edge 24 of the paperboard into proper position within the channel 18, 32.

Figure 4 shows a plan view of the frame 26 apart from the container 10. The frame 26 may take on any shape desirable to fit a particular shape of a container opening 14. The rectangular shape shown in Figure 4 is provided for example purposes and should not be considered as limiting the scope of the present invention. The adhesive polymer sealant material 22 may be placed within the channel 32 of the frame prior to assembly. The sealant 22 may be

comprised ofa carbon or metallic material and a polymer, such as polypropylene.

Figure 5 reveals a preferred embodiment of the steps for the preparation ofa package hd incorporating the features of the present invention. Step 1 shows the initial loading step of arranging a plurality of preformed Ms or inserts onto machinery, such as an injection molding machine. In Step 2 the inserts are injection molded into the frames comprising the Ms. The frames may actually be created at this stage of the process, in the injection molding machine. In Step 3 the frames are filled with the sealant material. The material is preferably placed in a channel formed in the frame. In Step 4 the Ms may be off-loaded for application to a package filling process to be prepared for assembly onto a package.

The present invention may be further configured to advance the purpose of packaging as shown in Figures 6 and 7. A polyethylene membrane 34 may be secured to the undersurface 36 of the frame and insert prior to placement onto the package. Other portions of the frame and insert may also have a membrane layer thereon, which is left to the manufacturer's discretion according to his particular application for the present invention. For example, in Figure 7 the entire Kd structure is encapsulated by a membrane layer. Once in position on the package opening

the membrane may be heat sealed creating a bond between the package and the frame in much the

same way as the sealant material creates a bond as described above. In this embodiment, the polyethylene membrane will form a bond inside the channel causing the paperboard and frame to

be secured together in the channel. For access to the package contents, the membrane would be

punctured when a portion of the insert is opened. Specific areas of the membrane, around critical joints, would adhere to the insert. Figure 8 shows a preferred package filling arrangement in which the packages of the present invention may be filled with product, closed, sealed, and prepared for shipment.

The present invention is not intended to be construed as limited to the particular embodiments described above. It will be apparent to those skilled in the art that numerous modifications, variations, substitutions, and equivalents for features of the invention described herein, do not materially depart from the scope of this invention. The embodiments disclosed are to be regarded as illustrative rather than restrictive. Accordingly, it is expressly intended that all such modifications, variations, substitutions, and equivalents which fall within the spirit and scope of the invention as defined by the claims be embraced thereby.