CA2520024A1

CA2520024A1 - Liquid container with uninterrupted comfort band and method of forming same

Info

Publication number: CA2520024A1
Application number: CA 2520024
Authority: CA
Inventors: Gerald Van Handel
Original assignee: Individual
Current assignee: GPCP IP Holdings LLC
Priority date: 2004-09-17
Filing date: 2005-09-16
Publication date: 2006-03-17
Anticipated expiration: 2025-09-16
Also published as: CA2520024C

Abstract

The sidewall portion of a cup or other container for a heated beverage or other hot liquid comprises a relatively rigid outer wall and a relatively flexible inner liner. The wall and liner are attached together at respective upper and lower circumferential bands and at least an intermediate portion of the liner between the upper and lower circumferential bands is separable from the outer wall, to thereby form a sealed void between the outer wall and the inner liner which extends circumferentially along the entire comfort band and which defines a comfort band encircling at least a middle region of the cup. In one embodiment, a liner preform is placed on a tapered mandrel provided with selectively heated circumferential bands for sealing the upper and lower circumferential bands of the liner to an inner surface of the outer wall. Preferably, the container is a stackable disposable cup with a liner formed of a heat shrinkable material which is activated (i.e., has its tension released) only after the cup is filled with a hot liquid.

Claims

1. A sidewall surrounding the interior of a container, said sidewall comprising:
a rigid outer wall, and a flexible inner liner, wherein the outer wall and the inner liner are attached together at respective upper and lower circumferential bands of the liner, and at least an intermediate portion of said liner between the upper and lower circumferential bands is separable from the outer wall to thereby form a sealed void defining a comfort band encircling said container between said upper and lower circumferential bands, and said sealed void is defined at least in part by an outer surface of the inner liner and an inner surface of the outer wall.

2. The sidewall of claim 1 wherein the inner liner is formed from a heat shrinkable plastic material and, in response to the application of heat to said inner liner, said outer surface is spaced apart from said inner surface along the entirety of an intermediate circumference between said upper and lower circumferential bands.

3. The sidewall of claim 2 wherein said sidewall forms a cup for a heated beverage, and heat from the beverage causes the liner to shrink away from the outer wall.

4. The sidewall of claim 1 wherein the inner surface of the outer wall is coated with a plastic material.

5. The sidewall of claim 4 wherein the plastic material is a polyethylene plastic material.

6. The sidewall of claim 1 wherein the inner liner is formed of a biaxially oriented heat shrinkable plastic material.

7. The sidewall of claim 6 wherein the container is a stackable disposable cup and the liner is activated only after the cup is filled with a hot liquid, whereby the liner remains in close contact with the outer sidewall prior to use by the consumer and two or more unused cups may be conveniently stacked inside one another without the liner of a lower cup pressing against the outer sidewall of an upper cup.

8. The sidewall of claim 1 wherein the inner surface of the outer wall is coated with a polyethylene plastic material, the inner liner is formed of a heat shrinkable plastic material, and a sealed insulating airspace is formed by heat sealing the heat shrinkable plastic material to the polyethylene plastic coating.

9. A stackable insulated cup for holding a hot beverage, said cup having a generally frusto-conical shape and comprising:
a tapered sidewall portion including a rigid outer wall and a flexible inner lining wherein the inner lining is attached to the outer wall at respective upper and lower circumferential bands of the inner lining, to thereby form a sealed void between said outer wall and said lining; and a circular bottom portion attached to the tapered sidewall, wherein said sealed void is defined by an outer surface of the flexible inner lining and an inner surface of the rigid outer wall, said outer surface is separable from said inner surface along the entirety of an intermediate circumference between said upper and lower circumferential bands, the inner surface of the outer wall is coated with a polyethylene plastic material, the inner wall is formed of a heat shrinkable plastic material, and the sealed void is formed by heat sealing the heat shrinkable plastic material to the polyethylene plastic coating.

10. The stackable insulated cup of claim 9 wherein the heat shrinkable plastic material is activated only after the cup is filled with a hot liquid, whereby the liner remains in close contact with the outer sidewall prior to consumer use and two or more unused cups may be stacked inside one another without the liner of a lower cup pressing against the outer sidewall of an upper cup.

11. The stackable insulated cup of claim 9 wherein said rigid outer wall has a generally frusto-conical shape with an overlapping side seam, the overlapping side seam extends from below the bottom circumferential band to above the top circumferential band, and the outer surface of the inner wall is separable from at least a portion of said side seam in the vicinity of said intermediate circumference.

12. The stackable insulated cup of claim 9 wherein said rigid outer wall is made of disposable paperboard.

13. A method for manufacturing a tapered container with insulated sidewalls, comprising:
forming a flexible preform from an elastic plastic material;

placing the preform over a tapered mandrel between a smaller lower circumference to a larger upper circumference, to thereby form a flexible inner liner having a generally frusto conical shape with a lower circumferential band adjacent said lower circumference and an upper circumferential band adjacent said upper circumference;
covering the flexible inner liner with a rigid outer wall;
sealing the outer wall to the inner liner at said upper and lower circumferential bands to thereby form a sidewall of the container;
removing the sidewall from the mandrel; and permitting at least an intermediate portion of the inner wall to separate from the outer wall to thereby form an insulating comfort band along the entirety of an intermediate circumference between upper and lower circumferential bands of said liner.

14. The method of claim 13 wherein said mandrel comprises a pair of selectively heated bands in respective contact with said lower and upper circumferential bands.

15. The method of claim 13 wherein the flexible preform comprises a single sheet of heat shrinkable plastic generally in the shape of a sector of an annulus and the flexible inner liner comprises a vertical seam connecting two radial edges of said sector.

16. The method of claim 15 wherein the mandrel comprises a selectively heated vertical band in contact with said vertical seam.

17. The method of claim 13 wherein the flexible preform comprises two similarly shaped layers of heat shrinkable plastic and the flexible inner liner comprises a respective seam connecting the two layers at each of two edges of said preform.

18. The method of claim 17 wherein each said respective seam is formed prior to placing said preform on said mandrel.

19. The method of claim 13 wherein the flexible preform comprises a tube that is pulled over the mandrel.

20. The method of claim 19 wherein the tube includes a pair of outwardly extending fins that are secured to a respective pair of grippers as the tube is being pulled over the mandrel.

21. The method of claim 19 wherein an original diameter of the tube is less than or equal to a lower diameter of said mandrel at said lower circumferential band and is substantially less than an intermediate diameter of said mandrel at said intermediate circumference, whereby when said sidewall is removed from said mandrel, an intermediate portion of the flexible tube will tend to shrink from said intermediate diameter to said original diameter.

22. The method of claim 19 wherein the tube is formed from a heat shrinkable plastic.

23. The method of claim 13 wherein said mandrel comprises a pair of selectively heated bands in respective contact with said circumferential bands.

24. The method of claim 13 wherein the liner is formed from a heat shrinkable plastic and any heat produced during the sealing operation is confined to the upper and lower circumferential bands of the liner, thereby not releasing the tension in the intermediate portion of the liner material such that the liner may remain in close contact with the outer sidewall prior to filling with a hot liquid and two or more unused containers may be stacked inside one another without the liner of a lower container pressing against the outer sidewall of an upper container.