Envelopes – wrappers – and paperboard boxes – Paperboard box – Multi-layer side or bottom wall having two or more layers of...
Reexamination Certificate
2000-03-06
2001-02-13
Elkins, Gary E. (Department: 3727)
Envelopes, wrappers, and paperboard boxes
Paperboard box
Multi-layer side or bottom wall having two or more layers of...
C229S004500, C229S122320, C229S403000, C229S406000
Reexamination Certificate
active
06186394
ABSTRACT:
TECHNICAL FIELD
The present invention is directed to paperboard containers formed from a composite web and more particularly to the formation of containers formed from layer embossed paperboard sheets and methods of forming such containers.
BACKGROUND OF THE INVENTION
It is well known in the art to form disposal containers such as cups, bowls, plates or trays from a variety of material, particularly from paper, expanded resins or polystyrene. In this regard, polystyrene containers are aesthetically pleasing, however, they can only be used for holding cold products and are not biodegradable or recyclable. Containers formed of expanded synthetic resin material have found wide acceptance in that the material is an excellent thermal insulator such that the containers can maintain the temperature of the food product whether hot or cold for long periods of time. However, as with polystyrene, such containers are not environmentally friendly in that they are not biodegradable or recyclable. As a result, many municipalities and establishments are turning away from the use of such material.
Standard single layer paper containers are recyclable and are therefore environmentally sound. However, because the single layer paper container is a poor insulator, any food product placed in such container will quickly achieve ambient temperature, thus losing any heat or coolness associated with the product. Moreover, when handling extremely hot or cold food products, such food products are uncomfortable to handle with single layer paper containers. Particularly, any hot food product placed in a single layer container may burn the consumer whereas a cold food product will cause condensation on the outside of the container making them slippery and difficult to handle. Furthermore, while the single layer construction is very inexpensive, such containers are fragile and can easily lose their shape when being used.
In an effort to overcome the aforementioned shortcomings, numerous multi-layer containers have been developed.
U.S. Pat. No. 3,908,523 issued to Shikaya is directed to a multi-layer container wherein as at least one layer of the container is a corrugated layer. However, when manufacturing containers such as cups which require the formation of a brim curl or other formation of an upper periphery of the container, the flexibility of corrugated paperboard is limited. Accordingly, the versatility of containers formed utilizing such corrugated layers is limited.
In an effort to overcome the aforementioned shortcomings, U.S. Pat. No. 5,092,485 issued to Lee discloses a paper container formed of multiple layers wherein an internal layer is similarly formed of corrugations. In order to overcome the problems encountered in forming the brim about an upper periphery of the container, the container of the '485 patent is formed from three distinct layers including an outer shell, a middle corrugated layer and an inner shell having a brim curl previously formed thereon. Clearly, such container requires minimal tolerance between the layers and consequently increases manufacturing costs. Moreover, the container continues to falter by being extremely rigid in one direction while being extremely pliable in the direction parallel to the corrugations.
In yet another effort to overcome the aforementioned shortcomings associated with prior containers, U.S. Pat. No. 3,363,982 issued to Sadlier discloses a multi-layer insulated container formed from a continuous sheet. Therein, the container is formed from a sheet having a first layer and third layers of greater dimensions than that of the corrugated central layer such that the inner and outer layers may readily receive a bottom portion and such that the brim curl can more readily be formed about an upper periphery of the container. While such a container, in fact, overcomes a number of the shortcomings associated with the prior art containers, this container still falters in that the container lacks substantial stability in the direction parallel to the corrugations.
Moreover, with each of the above-noted containers, while containers in the form of cups can be readily formed, containers having other configurations such as plates, bowls or trays are not readily formed in the manner set forth therein. Accordingly, the teachings of the aforementioned prior art containers are not readily adaptable to the formation of various types of containers.
In yet a further effort to overcome these shortcomings, an embossed or dimpled combined paperboard product is disclosed in each of U.S. Pat. Nos. 5,316,622 and 5,374,468 issued to Babinsky et al. Therein, embossed or dimpled combined paperboard product is formed wherein an inner layer of embossed material is sandwiched between two substantially planar layers of paperboard material of substantially the same thickness. These combined layers form a paperboard product of greater thickness and rigidity than that of a conventional three-ply board, however, this paperboard product as well as the method of manufacturing such product is highly suitable for the formation of paperboard boxes, however, such a product is not readily suitable for the formation of containers such as cups, plates, bowls or trays.
Clearly, there is a need for a composite paperboard material formed of layers of lightweight paper in which one or more of the layers are heavily embossed such that the composite paperboard can be used in the formation of cups, plates, bowls or trays which may be readily formed from the composite material.
SUMMARY OF THE INVENTION
A primary object of the present invention is to overcome the aforementioned shortcomings associated with the prior art containers.
Yet another object of the present invention is to provide a container which resists bending while providing thermal insulation.
A still further object of the present invention is to provide a composite paperboard material which can accommodate bends or curves in products such as cups, plates, bowls or trays.
Yet another object of the present invention is to provide methods of manufacturing cups, plates, bowls or trays from a composite paperboard material without destroying the inherent stiffness of the composite web.
A still further object of the present invention is to provide a composite web which includes air gaps between the layers of the composite structure to produce a thermal resistance significantly higher than that of a solid board made of an equivalent amount of material.
Yet another object of the present invention is to provide a composite paperboard material exhibiting high flexural stiffness as well as low buckling resistance of lightweight paper.
Another object of the invention is to provide methods of manufacturing paperboard cups, plates, bowls or trays from the composite paperboard material wherein the containers are formed by laminating separate layers around a mandrel or in a die in the form of the container desired.
These, as well as additional objects of the present invention, are achieved by providing a composite paperboard container including a first substantially planar sheet of paperboard material having a content contacting surface and a back surface, a first embossed sheet of paperboard material having a plurality of raised portions adhered to the back surface of the first planar sheet and a second embossed sheet of paperboard material having a plurality of raised portions adhered to the first embossed sheet of paperboard material. Additional planar sheets or embossed sheets may be added as desired in order to achieve the desired flexural stiffness and thermal resistance. Such containers being in the form of cups, plates, bowls or trays and formed by providing the substantially planar sheet of paperboard material, forming the planar sheet of paperboard material into a container shell, providing a first embossed sheet of paperboard material having raised portions and adhering the raised portions of the first embossed sheet of paperboard material to the planar sheet of paperboard material, providing a second embossed sheet of paperboard material ha
Dees Jerome G.
Kimbel Kirk
Elkins Gary E.
Fort James Corporation
Nixon & Peabody LLP
Studebaker Donald R.
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