Stock material or miscellaneous articles – Structurally defined web or sheet – Including variation in thickness
Reexamination Certificate
1997-04-11
2001-11-20
Dye, Rena L. (Department: 1772)
Stock material or miscellaneous articles
Structurally defined web or sheet
Including variation in thickness
C428S195100, C428S318400, C428S319300, C428S537500, C428S036500, C264S045100, C156S079000
Reexamination Certificate
active
06319590
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to heat-insulating stock material and containers having a foamed layer of a thermoplastic film thereon and methods for producing the stock material and containers. More particularly, the present invention is directed to controlling the expansion of the foamed layer on the surface of the stock material or container.
BACKGROUND OF THE INVENTION
Several types of heat-insulating containers have been used commercially to pack hot liquids. A polystyrene foam heat-insulating container is one example. It is prepared by casting unfoamed polystyrene into a mold, heating the resin under pressure to foam it, and removing the foamed resin from the mold. Alternatively, a foamed styrene sheet may be shaped into a container. The container thus produced has outstanding heat-insulating properties but, on the other hand, it needs reconsideration from the viewpoint of saving petroleum resources or increasing the efficiency of incinerating waste containers. As a further problem, a slow, inefficient and high waste printing process is required to print on the outer surfaces of polystyrene foam heat-insulating containers since printing can only be effected after individual cups have been shaped. Further, the tapered surface of the container contributes to print flur at positions near the top and bottom of the container unless specialized and expensive printing technology is employed. As a further disadvantage, the outer surface of the foamed styrene heat-insulating container is often not sufficiently smooth to accept high resolution screen printing further affecting printability. Thus, the polystyrene foam containers suffer the disadvantage of low printability.
The conventional paper heat-insulating container can not be manufactured at low cost, and one reason is the complexity of the manufacturing process. One example is a container wherein the side wall of the body member is surrounded by a corrugated heat-insulating jacket. The process of manufacturing such container involves additional steps of forming the corrugated jacket and bonding it to the outer surface of the side wall of the body member. One defect of this type of container is that letters, figures or other symbols are printed on the corrugated surface and the resulting deformed letters or patterns do not have aesthetic appeal to consumers. Another defect is that the jacket is bonded to the side wall of the body member in such a manner that only the valley ridges contact the side wall, and the bond between the jacket and the side wall, and the bond between the jacket and the side wall is so weak that the two can easily separate. Often times, corrugated containers are not suitable for stacking and thus require large storage space.
Another type of paper heat-insulating container has a “dual” structure wherein an inner cup is given a different taper than an outer cup to form a heat-insulating air layer. The two cups are made integral by curling their respective upper portions into a rim. The side wall of the outer cap is flat and has high printability, however, the two cups may easily separate. Another disadvantage is that the dual structure increases the manufacturing cost.
U.S. Pat. No. 4,435,344 issued to Iioka teaches a heat-insulating paper container consisting of a body member and a bottom panel member, characterized in that at least one surface of the body member is coated or laminated with a foamed heat-insulating layer of a thermoplastic synthetic resin film whereas the other surface of the body member is coated or laminated with a thermoplastic synthetic resin film, a foamed heat-insulating layer of thermoplastic synthetic resin film or an aluminum foil. When manufacturing such a container, the water in the paper is vaporized upon heating, causing the thermoplastic synthetic resin film on the surface to foam. The container under consideration has the advantage that it exhibits fairly good heat-insulating properties and that it can be manufactured at low cost by a simple process. However, the thermoplastic synthetic resin film will not foam adequately if the water content in the paper is low. While high water content is advantageous for the purpose of film foaming, the mechanical strength of the container may deteriorate. Moreover, even if successful foaming is done, the thickness of the foam layer is uniform and cannot be controlled from one portion of the container to another. Further, the foam layer reaches an expansion limit regardless of the moisture content of the base layer.
In an effort to overcome the aforementioned shortcomings, U.S. Pat. No., 5,490,631 issued to Iioka discloses a heat-insulating paper container including a body wherein part of the outer surface of the body members provided with a printing of an organic solvent based ink. The body portion is subsequently coated with a thermoplastic synthetic resin film which when heated forms a thick foamed heat-insulating layer in the printed area of the outer surface whereas a less thick foamed heat-insulating layer is formed in the non-printed areas. Further, there are portions of the outer surface which remain unfoamed. In manufacturing a container in this manner, the printing is carried out on the paperboard layer and consequently viewing of the printed matter by the consumer is obstructed by the foamed insulating layer. Moreover, because the foamed layer overlying the printed areas are thicker than the remaining portions of the foamed layers, these areas will be even more obstructed. Consequently, this container suffers from similar drawbacks as those containers discussed hereinabove.
Accordingly, there is a need for insulated stock material and containers wherein the expansion of the foamed layer on the surface of the stock material or container is controlled and which includes printed matter which may be readily observed by the consumer while providing a container presenting an appearance of having been debossed or embossed.
SUMMARY OF THE INVENTION
A primary object of the present invention is to overcome the aforementioned shortcomings associated with the containers discussed hereinabove.
A further object of the present invention is to provide a heat-insulating container wherein the expansion of the insulating layer is controlled by way of printed matter on an outer surface of the heat-insulating layer.
Yet another object of the present invention is to provide a decorative heat-insulating container and stock material for forming the same wherein the container appears to be either debossed or embossed without actually carrying out such a process.
Yet another object of the present invention is to provide a heat-insulating container wherein the expansion of the heat-insulating layer is maximized.
Still another object of the present invention is to provide a heat-insulating container and stock material wherein the expansion of the foam layer is enhanced while still providing a smooth outer surface.
A still further object of the present invention is to provide a heat-insulating container and stock material for forming the same which includes not only enhanced foaming but further controls the foaming in selected areas so as to create the appearance of a debossed or embossed surface.
These as well as additional advantages of the present invention are achieved by forming an insulating container comprising a container body having at least one side wall and a bottom wall with the at least one side wall including a paper base layer, an insulating layer on at least a portion of the paper base layer and a printed pattern printed on at least a portion of the surface of the insulating layer wherein a thickness of the insulating layer is controlled by the printed pattern printed on the selected portion of the insulating layer. Similarly, stock material incorporating the present invention includes a base layer, an insulating layer formed on at least a portion of at least one surface of the base layer and a printed pattern printed on at least a portion of the surface of the insulating layer wherein the thickness of the
Breining Michael Andrew
Geddes Daniel James
Schmelzer Michael
Dye Rena L.
Fort James Corporation
Nixon & Peabody LLP
Studebaker Donald R.
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