Container having a rolled rim, and method of making the same
View Patent ↗A blank for a container having a rolled rim, comprising a hollow body of polyolefin material, having an open first end and an opposite second end with a sidewall extending between the first end and the second end, and a rim formed at the first end of the hollow body. The rim includes a flange extending outwardly from the sidewall, the flange defining a flange thickness and having an inner portion proximate the sidewall and an outer portion opposite the inner portion. The rim further includes a skirt extending downwardly from the outer portion of the flange, the skirt defining a skirt thickness and having an upper portion proximate the flange and a lower portion opposite the upper portion, the flange thickness being greater than the skirt thickness.
1. A container having a rolled rim, comprising:
a hollow body of a thermoformed sheet consisting essentially of unfoamed polyolefin material, having an open first end and an opposite second end with a sidewall extending between the first end and the second end;
a rigid rolled rim formed of the unfoamed polyolefin material at the first end of the hollow body, the rigid rolled rim including a flange extending outwardly from the sidewall, the flange defining a flange thickness and having an inner portion proximate the sidewall and an outer portion opposite the inner portion, the rigid rolled rim further including a skirt extending downwardly from the outer portion of the flange toward the sidewall, the skirt defining a skirt thickness and having an upper portion proximate the flange and a lower portion opposite the upper portion, the flange thickness being greater than the skirt thickness.
2. The container of claim 1 , wherein the flange thickness is at least about twice the skirt thickness prior to being rolled.
3. The container of claim 1 , wherein the skirt thickness varies between the upper portion and the lower portion prior to being rolled.
4. The container of claim 3 , wherein the skirt thickness decreases from the upper portion to the lower portion.
5. The container of claim 4 , wherein the skirt thickness decreases from the upper portion to the lower portion defining a taper, the taper is approximately 3 degrees from normal.
6. The container of claim 1 , wherein the outer portion of the flange and the upper portion of the skirt form a joint therebetween prior to being rolled.
7. The container of claim 6 , wherein the joint includes an upper surface having an outer radius and a lower surface having an inner radius, the outer radius being at least about twice the inner radius.
8. The container of claim 7 , wherein the outer radius is approximately 0.033 inches and the inner radius is approximately 0.016 inches.
9. The container of claim 6 , wherein the joint defines a hinge point between the skirt and the flange.
10. The container of claim 6 , wherein the joint defines a joint thickness, the joint thickness is less than the flange thickness.
11. The container of claim 1 , wherein the flange extends outward from the sidewall at approximately 90 degrees from the sidewall.
12. The container of claim 1 , wherein the skirt extends at an angle of approximately 90 degrees from the flange prior to being rolled.
13. The container of claim 1 , wherein the flange has a width between the inner portion and the outer portion of at least approximately 0.165 inches.
14. The container of claim 1 , wherein the container is selected from: a cup, a plate, a bowl, and a lid.
15. The container of claim 1 , wherein the second end is closed to define a bottom wall.
16. The container of claim 1 , wherein the hollow body is a single piece.
17. A method for forming a container having a rolled rim, comprising:
providing a thermoformable sheet consisting essentially of unfoamed polyolefin material;
thermoforming the sheet of unfoamed polyolefin material to form a hollow body having an open first end and an opposite second end with a sidewall extending between the first end and the second end, and a rim formed at the first end of the hollow body, the rim including a flange extending outwardly from the sidewall, the flange defining a flange thickness and having an inner portion proximate the sidewall and an outer portion opposite the inner portion, the rim further including a skirt extending downwardly from the outer portion of the flange, the skirt defining a skirt thickness and having an upper portion proximate the flange and a lower portion opposite the upper portion, the flange thickness being greater than the skirt thickness; and
rolling the rim to form a rigid rolled rim along the open first end of the hollow body, wherein the skirt extends toward the sidewall after being rolled.
18. The method of claim 17 , wherein the flange thickness is at least about twice the skirt thickness prior to being rolled.
19. The method of claim 17 , wherein the skirt thickness varies between the upper portion and the lower portion prior to being rolled.
20. The method of claim 19 , wherein the skirt thickness decreases from the upper portion to the lower portion.
21. The method of claim 20 , wherein the skirt thickness decreases from the upper portion to the lower portion defining a taper, the taper is approximately 3 degrees from normal.
22. The method of claim 17 , wherein the outer portion of the flange and the upper portion of the skirt form a joint therebetween prior to being rolled.
23. The method of claim 22 , wherein the joint includes an upper surface having an outer radius and a lower surface having an inner radius, the outer fadius being at least about twice the inner radius.
24. The method of claim 23 , wherein the outer radius is approximately 0.033 inches and the inner radius is approximately 0.016 inches.
25. The method of claim 22 , wherein the joint defines a hinge point between the skirt and the flange.
26. The method of claim 22 , wherein the joint defines a joint thickness, the joint thickness is less than the flange thickness.
27. The method of claim 17 , wherein the flange extends outward from the sidewall at approximately 90 degrees from the sidewall.
28. The method of claim 17 , wherein the skirt extends at an angle of approximately 90 degrees from the flange prior to being rolled.
29. The method of claim 17 , wherein the flange has a width between the inner portion and the outer portion of at least approximately 0.165 inches.
30. The method of claim 17 , wherein the container is selected from: a cup, a plate, a bowl, and a lid.
31. The method of claim 17 , wherein the second end is closed to define a bottom wall.
32. The method of claim 17 , wherein the hollow body is a single piece.
33. The container of claim 1 , wherein the polyolefin material is selected from: polypropylene, high-density polyethylene, or blends thereof.
34. The method of claim 17 , wherein the polyolefin material is selected from: polypropylene, high-density polyethylene, or blends thereof.
35. The container of claim 1 , wherein the polyolefin material includes at least one of filler or additive.
36. The method of claim 17 , wherein the polyolefin material includes at least one of filler or additive.
37. The container of claim 1 , wherein the container is formed from a blank.