Title:
Polymeric container
Kind Code:
A1


Abstract:
A container has a bottom formed from polymeric material having a floor and a skirt projecting from the floor and a sidewall formed from polymeric material having opposite sides joined to one another and a lower end joined to the skirt so as to form an interior having a mouth, wherein the mouth has a dimension not less than the floor.



Inventors:
Fritz, James J. (West Bend, WI, US)
Hansen, Michael F. (Mequon, WI, US)
Johnson, Craig N. (Germantown, WI, US)
Johnson, Gary L. (Delafield, WI, US)
Application Number:
11/195582
Publication Date:
12/28/2006
Filing Date:
08/02/2005
Assignee:
Paper Machinery Corporation
Primary Class:
Other Classes:
229/400
International Classes:
B65D3/00
View Patent Images:



Primary Examiner:
GROSSO, HARRY A
Attorney, Agent or Firm:
FOLEY & LARDNER LLP (3000 K STREET N.W. SUITE 600, WASHINGTON, DC, 20007-5109, US)
Claims:
What is claimed is:

1. A container comprising: a bottom formed from a polymeric material having a floor and a skirt projecting from the floor; and a sidewall formed from a polymeric material having opposite sides joined to one another and a lower end joined to the skirt so as to form an interior having a mouth, the mouth having a dimension not less than the floor.

2. The container of claim 1, wherein the skirt has an edge and wherein the lower end of the sidewall wraps about the edge.

3. The container of claim 1, wherein at least one of the bottom and the sidewall is formed from polypropylene.

4. The container of claim 1, wherein at least one of the bottom and the sidewall includes a layer of recycled polypropylene material sandwiched between two layers of virgin polypropylene material.

5. The container of claim 1, wherein the container has an interior, wherein at least one of the bottom and the sidewall has an inner layer of virgin polymeric material adjacent the interior and a layer of recycled polymeric material adjacent an exterior to the layer of virgin polymeric material.

6. The container of claim 5, wherein the inner layer of virgin polymeric material has a minimum thickness of at least about 0.001 inches.

7. The container of claim 6, wherein the inner layer of virgin polymeric material has a maximum thickness of no greater than 0.040 inches.

8. The container of claim 5, wherein the inner layer of virgin polymeric material has a maximum thickness of no greater than 0.040 inches.

9. The container of claim 5, wherein the layer of recycled polymeric material has a minimum thickness of 0.005 inches.

10. The container of claim 5, wherein the layer of recycled polymeric material has a maximum thickness of no greater than 0.040 inches.

11. The container of claim 5 including an outer layer of polymeric material adjacent an exterior to the layer of recycled polymeric material.

12. The container of claim 11, wherein the outer layer of virgin polymeric material has a minimum thickness of no greater than 0.001 inches.

13. The container of claim 12, wherein the outer layer of virgin polymeric material has a maximum thickness of no greater than 0.040 inches.

14. The container of claim 11, wherein the outer layer of virgin polymeric material has a maximum thickness of no greater than 0.040 inches.

15. The container of claim 1, wherein the sidewall has a maximum thickness of no greater than 0.040 inches.

16. The container of claim 1, wherein the sidewall has a minimum thickness of at least 0.007 inches.

17. The container of claim 5, wherein at least one of the layers includes a filler material.

18. The container of claim 17, wherein the filler material comprises talc.

19. The container of claim 1, wherein at least one of the bottom and the sidewall includes a filler material.

20. The container of claim 1, wherein the skirt includes a plurality of inwardly extending notches.

21. The container of claim 20, wherein the notches are V-shaped.

22. The container of claim 21, wherein the notches have an outer most radial width of between about 0.2 inches and 0.3 inches.

23. The container of claim 21, wherein the ends of the notches are spaced between 0.1 inches and 0.125 inches from the floor.

24. The container of claim 20, wherein the notches are equally spaced about an entire perimeter of the skirt.

25. The container of claim 20 including at least 10 notches.

26. The container of claim 20, wherein the bottom includes a circular score at a junction of the floor and the skirt.

27. The container of claim 26, wherein the bottom has a thickness and wherein the circumferential score has a depth of at least one-half the thickness.

28. The container of claim 1, wherein the bottom has a plurality of inwardly extending scores.

29. The container of claim 28, wherein the plurality of scores extend from an edge of the skirt to the floor.

30. The container of claim 28, wherein the plurality of scores are uniformly spaced along an entirety of the skirt.

31. The container of claim 1, wherein the skirt includes a plurality of inwardly extending slits.

32. The container of claim 31, wherein the slits extend at least two-thirds of a radial width of the skirt.

33. The container of claim 31, wherein the slits are uniformly spaced along an entirety of the skirt.

34. The container of claim 1, wherein the skirt is fused to the sidewall.

35. The container of claim 1, wherein the bottom is formed entirely from at least one polymeric material.

36. The container of claim 1, wherein the sidewall includes printing on an outer surface.

37. A container comprising: a bottom having a floor and a skirt; and a sidewall having opposite side ends joined to one another and a lower end joined to the skirt to form a container interior, wherein at least one of the bottom and sidewall includes an inner layer of virgin polymeric material adjacent the interior and a layer of recycled polymeric material exterior to the layer of virgin polymeric material.

38. The container of claim 37, wherein at least one of the bottom and the sidewall is formed from polypropylene.

39. The container of claim 37 including an outer layer of virgin polymeric material adjacent to the layer of recycled polymeric material.

40. A container comprising: a bottom formed substantially from a polymeric material and having a floor and a skirt; and a sidewall formed substantially from a polymeric material having opposite sides joined to one another and a lower end joined to the skirt, wherein the skirt includes a plurality of resiliency lessening treatments.

41. The container of claim 40, wherein the resiliency lessening treatments comprise notches.

42. The container of claim 41, wherein the notches are V-shaped.

43. The container of claim 41, wherein ends of the notches are spaced between about 0.1 inches and about 0.125 inches from the floor.

44. The container of claim 41, wherein the notches are equally spaced about the entire perimeter of the skirt.

45. The container of claim 41, wherein the bottom includes a circular score at a junction of the floor and the skirt.

46. The container of claim 45, wherein the bottom has a thickness and wherein the circumferential score has a depth of at least one-half of the thickness.

47. The container of claim 40, wherein the resiliency lessening treatments comprise slits.

48. The container of claim 40, wherein the resiliency lessening treatments comprise scores.

49. The container of claim 40, wherein at least one of the bottom and the sidewall includes a layer of virgin polymeric material.

50. The container of claim 40, wherein the floor extends in a first plane and wherein the sidewall extends in a second plane perpendicular to the first plane.

51. A method for forming a container, the method comprising: forming a substantially planar bottom blank from a first sheet formed substantially from at least one polymeric material; forming a circumferential score in the bottom blank, the score separating the bottom blankblank into a floor and a skirt; bending the skirt relative to the floor; forming a substantially planar sidewall blank from a second sheet formed substantially from at least one polymeric material; joining opposite sides of the sidewall blank; and joining a lower end of the sidewall blank to the skirt such that the floor extends in a first plane and such that the sidewall extends in a second plane perpendicular to the first plane.

52. The method of claim 51 including treating the skirt at a plurality of spaced locations to weaken resiliency of the at least one polymeric material.

53. The method of claim 52, wherein treating includes scoring the skirt.

54. The method of claim 52, wherein treating includes slitting the skirt.

55. The method of claim 52, wherein treating includes notching the skirt.

56. The method of claim 51 including wrapping the lower end of the sidewall about an edge of the skirt.

57. The method of claim 51 including fusing the lower end of the sidewall to the skirt.

58. The method of claim 51, wherein the sheet includes a first layer of virgin polymeric material and a second layer of recycled polymeric material and wherein the method includes positioning the virgin polymeric material adjacent an interior of the cylinder.

59. A method for forming a container, the method comprising: forming a substantially planar bottom blank from a first sheet formed substantially from at least one polymeric material; forming a circumferential score in the bottom blank, the score separating the bottom blank into a floor and a skirt; bending the skirt relative to the floor; forming a substantially planar sidewall blank from a second sheet formed substantially from at least one polymeric material; joining opposite sides of the sidewall blank; and joining a lower end of the sidewall blank to the skirt, wherein at least one of the first sheet and the second sheet includes a first layer of virgin polymeric material and a second layer of recycled polymeric material and wherein the method further includes positioning the virgin polymeric material adjacent an interior of the container.

60. A method for forming a container, the method comprising: forming a substantially planar bottom blank from a sheet formed substantially from at least one polymeric material; forming a circumferential score in the bottom blank the score separating the bottom blank into a floor and a skirt; bending the skirt relative to the floor; forming a substantially planar sidewall blank from a sheet formed substantially from at least one polymeric material; joining opposite sides of the sidewall blank; and joining a lower end of the sidewall blank to the skirt, the additional step of treating the skirt at a plurality of spaced locations to weaken resiliency of the at least one polymeric material.

Description:

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims priority to co-pending U.S. Provisional Patent Application Ser. No. 60/598,550, filed on Aug. 2, 2004, by Fritz et al., entitled POLYMERIC CONTAINER, from which priority is claimed under 35 U.S.C. §119(e), the full disclosure of which, in its entirety, is hereby incorporated by reference.

BACKGROUND

Paperboard containers have been in use for many years. Despite their popularity, paperboard containers are not well suited for containing items that require either a moisture vapor barrier or a gas barrier.

Polymeric or plastic containers are better suited for containing substances that require a moisture vapor or gas barrier. Thermoforming such plastic containers requires the containers to have a tapered sidewall. In many instances, a true straight wall may be desired and is not achievable with thermoforming. Injection molding can be made straight wall, but is expensive and does not achieve high barrier requirements. Thermoforming requires an excessive amount of plastic material to accommodate the stretching and deformation of the plastic material during thermoforming. Moreover, the stretching or deformation of the plastic material during thermoforming prevents the printing of labels, data or images directly on the plastic material prior to the plastic material being shaped into a 3-dimensional container. Printing directly upon the plastic material after it has been shaped into a 3-dimensional container is costly and is limited in the quality of the image produced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of one example of a container according to one example embodiment.

FIG. 2 is a top plan view of one example of a sheet 60 from which a sidewall blank is provided according to one example embodiment.

FIG. 3 is a sectional view of the sidewall blank of FIG. 2 according to one example embodiment.

FIG. 4 is a top plan view of a bottom blank from which a bottom may be formed according to one example embodiment.

FIG. 5 is a sectional view of the bottom blank of FIG. 4 according to one example embodiment.

FIG. 6 is a sectional view of another embodiment of the cup of FIG. 1 according to an example embodiment.

FIG. 7 is a top plan view of one example of a sheet from which one embodiment of a bottom blank may be provided according to one example embodiment.

FIG. 8 is a top plan view of another sheet from which another embodiment of a bottom blank may be provided according to one example embodiment.

FIG. 9 is a top plan view of another sheet from which another embodiment of a bottom blank may be provided according to one example embodiment.

FIG. 10 is a side elevational view of another embodiment of the cup of FIG. 1 according to one example embodiment.

FIG. 11 is a fragmentary sectional view of the cup of FIG. 10 according to one example embodiment.

FIG. 12 is a top plan view of a sidewall blank from which the cup of FIG. 10 may be formed according to one example embodiment.

FIG. 13 is a side elevational view of another embodiment of the cup of FIG. 1 according to one example embodiment.

FIG. 14 is a fragmentary sectional view of the cup of FIG. 13 according to one example embodiment.

FIG. 15 is a top plan view of a sidewall blank from which the cup of FIG. 13 may be formed according to one example embodiment.

FIG. 16 is a top plan view of a sheet from which a bottom blank may be provided for forming the cup of FIG. 13 according to one example embodiment.

FIG. 17 is a top plan view of a machine for forming a cup according to one example embodiment.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 is a sectional view of a container 10 according to one exemplary embodiment. Container 10 includes bottom 12 and sidewall 16. Bottom 12 includes floor 18 and skirt 20. Skirt 20 projects from floor 18. Skirt 20 and floor 18 are integrally formed as part of a single unitary body. In particular, both floor 18 and skirt 20 of bottom 12 are substantially formed from at least one plastic or polymeric material.

Sidewall 16 comprises a panel substantially formed from at least one polymeric material. For purposes of this disclosure, the phrase “formed substantially from at least one polymeric material” means that a member, panel or structure is formed from one or more layers of plastic or polymeric material such that main structural support or a majority of the thickness of the member is provided by the plastic or polymeric material. In particular embodiments, the plastic or polymeric material may have disbursed or impregnated filler materials. The one or more layers of plastic or polymeric materials may also include much thinner layers of non-polymeric or plastic materials wherein such layers have a de minimus or insubstantial thickness such that the non-polymeric layer or layers add little to the overall thickness of the member or do not substantially increase the rigidity or strength of the member.

As shown by FIG. 1, sidewall 16 has a pair of opposite ends 22, 24 which are joined to one another. In the particular example shown, ends 22 and 24 overlap one another. Sidewall 16 further includes a lower end 26 which wraps about edge 28 of skirt 20. As a result, lower end 26 of sidewall 16 cooperates with skirt 20 of bottom 12 to form a 3-ply wall below floor 18. In the particular example shown, ends 22, 24 are joined to one another by heating and melting the exterior plastic or polymeric materials of sidewall 16 such that overlapping portions of ends 22 and 24 are fused to one another to form a substantially moisture impermeable and gas impermeable seal when sidewall 16 is formed from appropriate materials. Examples of materials that may be used to provide an effective moisture vapor transfer barrier include polypropylene and low density polyethylene. An example of a material that may be used to provide an effective gas or oxygen transfer barrier is ethylene vinyl alcohol (EVOH). In a similar fashion, polymeric surfaces 32, 34 and 36 of lower end 28 of sidewall 16, as well as surfaces 38 and 40 of skirt 20 of bottom 12 are heated so as to fuse skirt 20 to lower end 28 of sidewall 16. The heating of such surfaces may be achieved by radiant heat, convection heat or by generating friction such as by ultrasonic welding. Skirt 20 and end 28 as well as ends 22 and 24 may be joined with glue. Like the junction between ends 22 and 24, the junction between bottom 18 and sidewall 16 forms a substantially moisture impermeable and gas impermeable seal.

As further shown by FIG. 1, sidewall 16 includes an upper end 44 which is curled or rolled for up to 270 degrees to provide the mouth 46 of container 10 with a smooth surface. In the particular example shown, upper end 44 is curled utilizing a push in curl in which ends 44 are pushed towards bottom 18 to form the noted curl. Alternatively, ends 44 may be formed by multiple push in curls or spin curls.

Bottom 12 and sidewall 16, when joined, form container 10 which has interior 48. Like containers formed from thermoformed or injection molded plastic, container 10 provides an interior 48 well suited for containing liquids or other contents which require a moisture or gas impermeable barrier. Although not shown, container 10 may additionally be provided with a lid or cover. Unlike polymeric containers formed by thermoforming or injection molding, container 10 does not require stretching or deformation of those exterior portions 50 of sidewall 16 that extend generally above floor 18. In addition, the fabrication of container 10 does not require that portion 50 be subjected to extreme heat. As a result, at least portions 50 of sidewall 16 may be made from a thinner panel, requiring less material. In addition, portions 50 of sidewall 16 may be configured so as to extend along axes or planes 52 which are substantially perpendicular to the plane 54 of floor 18 of bottom 12, providing container 10 with a true straight sidewall. Moreover, portions 50 of sidewall 16 may have text and/or images preprinted directly upon the surface of sidewall 16 prior to ends 22, 24 being joined to one another and prior to sidewall 16 being converted from a generally flat 2-dimensional panel to a 3-dimensional structure as part of container 10. Such printing may be achieved with less chance of printing becoming distorted during the formation of container 10.

FIGS. 2-5 illustrate examples of materials from which bottom 12 and sidewall 16 may be formed. FIG. 2 is a top plan view of a sheet 60 from which a sidewall blank 62 is formed. FIG. 3 is a sectional view of the sidewall 62. In one embodiment, sidewall blank 62 is cut from sheet 60. According to one particular method, sidewall blank 62 is stamped from sheet 60 and is generally 2-dimensional. As shown by FIG. 3, sidewall blank 62 includes three substantially coextensive layers 64, 66 and 68. In one embodiment, layers 64, 66 and 68 are coextruded with one another. In another embodiment, layers 64, 66 and 68 are laminated to one another. Layer 64 generally comprises a layer of a recycled polymer. In one embodiment, layer 64 comprises recycled polypropylene. Layer 64 is sandwiched between layers 66 and 68. In other embodiments, one of layers 66 and 68 may be omitted. Although not shown, additional binding or tie layers may be added as needed.

Layer 66 comprises a layer substantially formed of a virgin polymer. In one embodiment, layer 66 is formed from virgin polypropylene. Because layer 66 is formed from virgin polypropylene, the surfaces of layer 66 may be positioned along interior 48 of container 10 (shown in FIG. 1) where it may come in contact with the content of container 10 such as a food or beverage.

Layer 68 comprises a layer of a virgin polymer. In the particular example shown, layer 68 comprises a layer of virgin polypropylene. Because layer 68 is formed from a virgin polymer, layer 68 may be located along an exterior of sidewall 16 where it may come into contact with food or beverages, a person's hand or other surfaces for which contact with layer 64 would be undesirable. Layer 66 and 68 cooperate with one another to substantially cover and seal off the recycled polymer of layer 64.

Because sheet 60 and sidewall blank 62 formed from it include layer 64 of a recycled polymer, sidewall blank 62 and the resulting container 10 may be less expensively formed. In addition, sidewall blank 62 and the resulting container 10 are more environmentally friendly in that at least a portion is formed utilizing the recycled polymer rather than being formed entirely from virgin polymer. The reduced cost and environmental benefit achieved by using a recycled polymer is further enhanced with the configuration of container 10. In particular, because container 10 is formed utilizing a two-piece construction, neither bottom 12 nor sidewall 16 need to be substantially deformed or stretched as would otherwise be required in a thermoforming process. Because neither bottom 12 nor sidewall 16 is substantially stretched or thinned during the formation of container 10, layers 66 and 68 of the virgin polymer may be made thinner with a lesser risk of layer 64 becoming exposed. Because layers 66 and 68 may be made thinner, less virgin polymer and a greater amount of recycled polymer may be utilized, lessening the cost and increasing the environmental friendliness of container 10.

In the particular example shown, layer 64 has a minimum thickness of at least 0.005 inches and a maximum thickness of no greater than 0.040 inches. Layer 66 has a minimum thickness of at least about 0.001 inches and a maximum thickness of no greater than 0.040 inches. Layer 68 has a minimum thickness of at least about 0.001 inches and a maximum thickness of no greater 0.040 inches. In the particular example illustrated, layers 64, 66 and 68 are each additionally provided with a filler material which is impregnated or disbursed throughout the one or more polymers. In one embodiment, the filler material comprises talc. The talc filler material lessens the resiliency or memory of the polymeric material forming layers 64, 66 and 68. In other embodiments, less than all the layers 64, 66 and 68 may be provided with a filler material. In still other embodiments, layers 64, 66 and 68 may each omit any filler material. In still other embodiments, sidewall 16 may be formed from a single layer (such as formed out of a homopolymer material) of a polymeric material with or without a filler material disbursed throughout.

FIG. 4 is a top plan view of a sheet 80 from which a bottom blank 82 is formed. FIG. 5 is an enlarged sectional view of bottom blank 82. Sheet 80 is generally a planar 2-dimensional structure from which bottom blank 82 is formed. In one embodiment, bottom blank 82 is cut from sheet 80. In the particular example shown, bottom blank 82 is stamped from sheet 80.

As shown by FIG. 5, bottom blank 82 includes three substantially coextensive layers 84, 86 and 88. In one embodiment, bottom blank 82 is cut from sheet 80. According to one particular method bottom blank 82 is stamped from sheet 80 and is generally 2-dimensional. As shown by FIG. 5, bottom blank 82 includes three substantially coextensive layers 84, 86 and 88. In one embodiment, layers 84, 86 and 88 are coextruded with one another. In another embodiment, layers 84, 86 and 88 are laminated to one another. Layer 84 generally comprises a layer of a recycled polymer. In one embodiment, layer 84 comprises recycled polypropylene. Layer 84 is sandwiched between layers 86 and 88. In other embodiments, one of layers 66 and 68 may be omitted.

Layer 86 comprises a layer substantially formed of a virgin polymer. In one embodiment, layer 86 is formed from virgin polypropylene. Because layer 66 is formed from virgin polypropylene, the surfaces of layer 66 may be positioned along interior 48 of container 10 (shown in FIG. 1) where it may come in contact with the content of container 10 such as a food or beverage.

Layer 88 comprises a layer of a virgin polymer. In the particular example shown, layer 88 comprises a layer of virgin polypropylene. Because layer 88 is formed from a virgin polymer, layer 88 may be located along an exterior of sidewall 16 where it may come into contact with food or beverages, a person's hand or other surfaces for which contact with layer 84 would be undesirable. Layer 86 and 88 cooperate with one another to substantially cover and seal off the recycled polymer of layer 84.

Because sheet 80 and sidewall blank 62 formed from it include layer 84 of a recycled polymer, sidewall blank 62 and the resulting container 10 may be less expensively formed. In addition, sidewall blank 62 and the resulting container 10 are more environmentally friendly in that at least a portion is formed utilizing the recycled polymer rather than being formed entirely from virgin polymer. The reduced cost and environmental benefit achieved by using a recycled polymer is further enhanced with the configuration of container 10. In particular, because container 10 is formed utilizing a two-piece construction, neither bottom 12 nor sidewall 16 need to be substantially deformed or stretched as would otherwise be required in a thermoforming process. Because sidewall 16 is not substantially stretched or thinned during the formation of container 10, layers 86 and 88 of the virgin polymer may be made thinner with a lesser risk of layer 84 becoming exposed. Because layers 66 and 68 may be made thinner, less virgin polymer and a greater amount of recycled polymer may be utilized, lessening the cost and increasing the environmental friendliness of container 10.

In the particular example shown, layer 84 has a minimum thickness of at least 0.005 inches and a maximum thickness of no greater than 0.040 inches. Layer 86 has a minimum thickness of at least about 0.001 inches and a maximum thickness of no greater than 0.040 inches. Layer 88 has a minimum thickness of at least about 0.001 inches and a maximum thickness of no greater 0.040 inches. In the particular example illustrated, layers 84, 86 and 88 are each additionally provided with a filler material which is impregnated or disbursed throughout the one or more polymers. In one embodiment, the filler material comprises talc. The talc filler material lessens the resiliency or memory of the polymeric material forming layers 84, 86 and 88. In other embodiments, less than all the layers 84, 86 and 88 may be provided with a filler material. In still other embodiments, layers 84, 86 and 88 may each omit any filler material. In still other embodiments, sidewall 16 may be formed from a single layer (such as formed out of a homopolymer material) of a polymeric material with or without a filler material disbursed throughout.

As further shown by FIGS. 4 and 5, bottom blank 82 additionally includes a circumferential score 90. Score 90 extends partly into or partly through the thickness of bottom blank 82. Circumferential score 90 facilitates the bending or other deformation of a perimeter portion of blank 82 along score 90 to form floor 18 and skirt 20. Although score 90 is illustrated as being continuous, score 90 may alternatively intermittently extend circumferentially along and substantially parallel to an edge perimeter of bottom blank 82. Although the edge perimeter of bottom blank 82 as well as score 90 are illustrated as being substantially circular, bottom blank 82 and score 90 may have other shapes and configurations depending upon the desired shape of container 10. For example, bottom 82 may alternatively be square or rectangular in shape with generally rounded corners. In other embodiments, bottom blank 82 may be oval. In such embodiments, the joining of ends 22 and 24 of sidewall 16 (shown in FIG. 1) and the joining of lower end 28 of sidewall 16 to bottom blank 82 would result in a container having a non-circular or non-cylindrical interior.

The formation of container 10 is generally as follows. Initially, sidewall blank 62 and bottom blank 82 are formed from sheets 60 and 80 which are formed from at least one polymeric material, respectively. Either before or after bottom link 82 is separated from sheet 80, scores 90 are formed which extend between floor 18 and skirt 20. Skirt 20 is bent or otherwise deformed relative to floor 18. Skirt 20 is joined to lower end 28 of sidewall blank 62 while ends 22 and 24 of sidewall blank 62 are joined to one another. In the embodiment in which sheet 60 and sheet 80 include a layer of recycled of polymer and an adjacent layer of virgin polymer, sidewall blank 62 and bottom blank 82 are positioned so as to position the layer of virgin polymer adjacent to an interior of the resulting container. Printing upon sidewall blank 62 is done before sidewall blank 62 is joined to bottom blank 82 and while sidewall blank 62 is in a generally 2-dimensional form. In the particular example shown, lower end 28 and/or skirt 20 are heated, ultrasonically welded, adhered with a hot melt or glue or otherwise treated so as to fuse, weld or otherwise join lower end 28 to skirt 20. In one particular embodiment, lower end 28 is wrapped about skirt 20. Although sidewall blank 62 is configured so as to form a substantially straight sidewall which extends along axes or in an arcuate plane substantially perpendicular to the plane in which floor 18 extends, sidewall blank 62 may alternatively be configured so as to form an outwardly tapered sidewall with respect to the plane in which floor 18 extends.

FIG. 6 is a sectional view of container 110, another embodiment of container 10 shown in FIG. 1. Container 110 is similar to container 10 except that lower end 26 of sidewall 16 does not wrap about end 28 of skirt 20 of bottom 12. Rather, surface 38 of skirt 20 and surface 32 of lower end 26 of sidewall 16 are sealed to one another. In one embodiment, the sealing is achieved by melting the polymer material of surfaces 32 and 38 to fuse the surfaces together, and to have melted polymer floor into gaps caused by the convolute forming process. In another embodiment, the fusion may be achieved by ultrasonic welding or adhesives.

In contrast to paperboard, plastic or polymeric materials have a much greater elasticity or shape memory. Moreover, plastic or polymeric material does not compress like paperboard. As a result, during bending of skirt 20 away from floor 18, portions of skirt 20 may overlap one another and build up. With paperboard material, the paper compresses. Due to its shape, memory or elasticity, the polymeric material of skirt 20 does not easily compress which may result in the formation of gaps between sidewalls 16 and skirt 20. These gaps present leakage issues and forming issues.

FIGS. 7-9 illustrate techniques for treating skirt 20 of bottom 12 (or of bottom blank 82) to lessen the resiliency or shape memory of skirt 20 and to reduce the likelihood of a potential leak causing gaps between skirt 20 and sidewall 16 (or sidewall blank 62). FIG. 7 is a top plan view of bottom blank 182 formed from sheet 80 described above with respect to FIG. 4. As noted above, sheet 80 includes three layers 84, 86 and 88 (shown in FIG. 5). In other embodiments, sheet 80 may alternatively comprise a single of polymeric material or a homopolymer plastic sheet. One or more layers 84, 86, 88 or an alternative homopolymer plastic sheet may additionally include an organic filler, such as talc. Like sidewall 16, bottom 12 (formed from bottom blank 82 or blank 182) may be opaque, translucent or clear.

Bottom blank 182 has a generally circular perimeter edge 192 and an inwardly spaced circumferential score 190. Score 190 extends partially into the thickness or caliber of bottom blank 182 to separate bottom blank 182 into floor 18 and skirt 20. In one particular embodiment, score 190 has a depth of one-half the thickness or caliber of bottom blank 182. In the particular embodiment, score 190 continuously extends circumferentially about a center of bottom blank 182 and is inwardly spaced from outer edge 192 by a minimum distance of at least 0.100 inches. In other embodiments, both outer edge 192 and score 190 may have shapes other than circles. For example outer edge 192 and score 190 may alternatively be oval, square or rectangular. In square and rectangular embodiments, the corners are rounded.

As shown by FIG. 7, skirt 20 of bottom blank 182 is additionally treated at a plurality of spaced locations to weaken the resiliency of one or more polymeric materials from which bottom blank 182 is formed. In the embodiment shown in FIG. 7, skirt 20 is treated by scoring. In particular, skirt 20 includes a plurality of uniformly or equally spaced scores 196. Scores 196 have a depth of at least one-third of the thickness or caliber of bottom blank 182. In the particular example shown, bottom blank 182 has a caliber thickness of 0.020 inches and scores have a depth of approximately 0.010 inches. Scores 196 extend from edge 192 to circumferential score 190. In the particular example shown, each score 190 has a length of at least 0.100 inches and nominally of about 0.375 inches. Scores 196 weaken the resilient nature or shape memory of the polymeric material of skirt 20 to facilitate bending of skirt 20 relative to floor 18 and to facilitate better securement of skirt 20 to sidewall 16.

FIG. 8 is a top plan view illustrating bottom blank 282 formed from sheet 80. Bottom blank 282 is similar to bottom blank 182 except that skirt 20 of bottom blank 282 is treated at a plurality of spaced locations with slits 296 in lieu of scores 196. Slits 296 comprise cuts which extend inwardly from outer edge 192 and which extend completely through the thickness or caliber of bottom blank 282. Slits 296 extend inwardly from outer edge 192 and have terminal ends 298 spaced from circumferential score 190. Slits 296 have a length such that terminal ends 298 are spaced from circumferential score 190 by at least 0.1 inches. In one embodiment, slits 296 have a length of approximately two-thirds of the bottom depth BD (FIG. 1). In other embodiments, slits 282 may have other lengths such that ends 298 are spaced from score 190 by other distances. A number of slits 296 as well as the uniform spacing of slits 296 is determined based upon the radial difference between outer edge 192 and circumferential score 190. In the particular example shown, slits 296 are evenly spaced from one another about the circumference.

Slits 296 weaken the resilient nature or shape of memory of skirt 20 to facilitate bending or deformation of skirt 20 relative to floor 18. Slits 296 further facilitate the joining of skirts 20 to sidewall 16. As compared to scores 196, slits 296 are relatively better at weakening the resilient nature of skirt 20, enabling easier and more reliable joining of skirt 20 to sidewall 16, improved heating and reducing the potential for leakage between bottom 12 and sidewall 16.

FIG. 9 is a top plan view illustrating bottom blank 382 formed from sheet 80. Bottom blank 382 is substantially similar to bottom blank 182 except that skirt 20 of bottom blank 382 is treated at a plurality of spaced locations to weaken the shape memory or resilient nature of the polymeric material of skirt 20 by notching in lieu of scoring. In particular, skirt 20 includes a plurality of inwardly extending notches 396. Notches 396 are different than scores 196 and slits 296 in that notches 396 are formed by removal of material from skirt 20. Because material is removed, notches 396 better minimize overlapping or pleating of skirt 20 when it is bent or deformed relative to floor 18 as compared to scores 196 or slits 296. By reducing pleating of skirt 20, notches 396 reduce the likelihood of leaks occurring between skirt 20 and sidewall 16 (shown in FIG. 1). Notches 396 further enable bottom blank 382 to be more easily formed into floor 12 and joined to sidewall 16.

As shown by FIG. 9, notches 396 are uniformly spaced about the entirety of skirt 20. The spacing and the quantity of notches 396 is determined based upon the radial distance between outer edge 192 and score 190. In the particular example shown, notches 396 have a radial length of approximately two-thirds of the bottom depth BD (FIG. 1). Notches 396 extend inwardly from outer edge 192 towards score 190. In the particular example shown, notches 192 are generally V-shaped. Because notches 396 are V-shaped, notches 396 better reduce shape memory of skirt 20. In other embodiments, notches 396 may have other shapes. In the particular example shown, notches 396 have end points 398 which terminate prior to reaching score 190. In the particular example shown, end points 398 are spaced from score 190 by a minimum radial distance of 0.1 inches and a maximum radial distance of 0.125 inches. In the embodiment shown, each notch 396 has a radial depth of about 0.02 inches and 0.03 inches.

Overall, containers 10 and 110 provide several advantages over typical paperboard containers and conventional thermoformed or injection molded polymeric containers. Unlike paperboard containers, containers 10 and 110 provide reliable moisture and gas impermeable sealed containers capable of containing foods and other content which are sensitive to moisture or gas. Unlike thermoformed polymeric containers, containers 10 and 110 enables the mouth of the container the same size as the opposite floor of the container. Containers 10 and 110 facilitate the preprinting of information or images upon the outer surface of sidewall 16 above floor 18 while sidewall 16 is in a 2-dimensional state with less distortion during the completion of the formation of the container. Containers 10 and 110 further facilitate thinner walled containers, the greater use of recycled polymeric materials and the conservation of virgin polymeric material due, in part, to sidewall 16 not being stretched or deformed to form the container. Containers 10 and 110, when having bottom 12 formed from bottom blank 182, 282 or 382 are easier to manufacture and are less likely to have leaks along the juncture of bottom 12 and sidewall 16.

Although containers 10 and 110 are each illustrated as having mouths 46 which have the same diameter as the opposite floor 18, containers 10 and 110 may alternatively have various other configurations. For example, containers 10 and 110 may have outwardly tapered sidewalls 16. FIGS. 10-13 illustrate container 410, another embodiment of container 10 (shown in FIG. 1). Container 410 is substantially similar to container 10 except that container 410 has outwardly tapering sidewalls 416. Those remaining components of container 410 which correspond to container 10 are numbered similarly. FIG. 13 illustrates sidewall 416 after it has been cut or formed from sheet 60 (described above). Sidewall 416 is joined to bottom 12 in a similar manner to that of the joining of sidewall 16 to bottom 12.

Although containers 10 and 110 are illustrated as being substantially imperforate along sidewall 16 and bottom 12, containers 10 and 110 may alternatively be perforate. FIGS. 13-16 illustrate container 510, another embodiment of container 10. Container 510 is similar to container 410 except that container 510 includes a perforated bottom 512 and sidewall 516 in lieu of bottom 12 and sidewall 416 of container 410. According to one embodiment, bottom 512 is formed from sheet 80 described above. In other embodiments, bottom 512 may be formed from sheets of other materials. As compared to bottom 12, bottom 512 additionally includes cutouts or notches 596 and perforations 598. Notches 596 minimize overlapping or pleating of skirt 20 when it is bent or deformed relative to floor 18. As a result, cutouts 96 reduce the likelihood of leaks occurring between skirt 20 and sidewall 516. Cutouts 596 further enable bottom blank 582 to be more easily formed into bottom 512 and joined to sidewall 516.

Perforations 598 constitute openings extending through floor 18 of bottom 512. Perforations 598 facilitate the escape of moisture from the interior of container 510 and the in-flow of external air into container 510. As a result, container 510 is well suited for containing soil, plants or other similar contents.

Sidewall 516 is similar to sidewall 416 except that sidewall 516 includes notches 602. Notches 602 have a sufficient depth or dimension so as to facilitate wrapping of sidewall 516 and bending of the lower end of sidewall 16 about skirt 20 of bottom 512 while minimizing overlapping of portions of sidewall 16 to reduce leakage potential. In other embodiments, notches 602 may be omitted.

Containers 10, 110, 410 and 510 may be formed using a variety of different machines. FIG. 17 illustrates a floor plan of one example of a machine 610 configured to form container 10, container 410 or container 510. In particular, the machine shown is configured to perform the above-described steps. Machine 610 generally includes mandrel turret 612, rimming turret 614, transfer turret 616, bottom maker 618, bottom preheat station 620, sidewall heater 622, blank or roll feed 624, bottom heat station 626, bottom in-curl station 628, rimming stations 630 and cup discharge 640. Bottom maker 618 forms bottom 12. In one embodiment, bottom maker 618 additionally includes hole puncher 632 for forming perforations 598 (shown in FIG. 16) when a cup such as cup 510 is being formed. In other embodiments, hole puncher 632 may be omitted.

Bottoms 12 formed by bottom maker 16 are carried by mandrel turret 612 to preheat station 620 where bottoms 12 are preheated prior to bonding of sidewall such as sidewall 16 thereto. Sidewalls, such as sidewalls 16, are formed by blank or feed roll 616 supplying sidewall blanks to transfer turret 624 which transfers the sidewalls to sidewall heater 622 and subsequently into position with respect to bottoms 12, where sidewalls 16 are wrapped about bottoms 12 and the sides of sidewall 16 are bonded to one another. Thereafter, mandrel turret 612 transfers the bottom sidewall assembly to bottom heat station which further secures bottom 12 to sidewall 16.

Mandrel turret 612 subsequently transfers the assembly to bottom in-curl station 628 where the lower end of sidewall 16 is curled about skirt 20. Once the lower end of sidewall 16 is curled about skirt 20 of bottom 12, the partially formed cup is transferred to rimming turret 614. In other embodiments where sidewall 16 is not curled or in-curled about skirt 20 of bottom 12, bottom in-curl station 628 may be omitted.

Rimming turret 614 transfers the cup to each of rimming station 630 which curl a top of sidewall 16. After the top of sidewall 16 has been curled, the finished cup is discharged at a cup discharge 614. FIG. 17 illustrates just one example of a machine for forming any one of cups 10, 110, 410 and 510. Other machines may also be utilized to form such cups.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. For example, although different preferred embodiments may have been described as including one or more features providing one or more benefits, it is contemplated that the described features may be interchanged with one another or alternatively be combined with one another in the described preferred embodiments or in other alternative embodiments. Because the technology of the present invention is relatively complex, not all changes in the technology are foreseeable. The present invention described with reference to the preferred embodiments and set forth in the following claims is manifestly intended to be as broad as possible. For example, unless specifically otherwise noted, the claims reciting a single particular element also encompass a plurality of such particular elements.