Controlled atmosphere package

• US 6,085,930 A
• Filed: 03/16/1998
• Issued: 07/11/2000
• Est. Priority Date: 11/13/1995
• Status: Expired due to Fees

• Current Assignee: Pactiv
• Original Assignee: Pactiv
• Inventors: Curtis, Danny S.
• Primary Examiner(s): POLLARD, STEVEN M
• Application Number:
  US09/039,672
• Time in Patent Office: 848 Days
• Field of Search: 220/371, 220/370, 220/256, 220/258, 206/508
• US Class Current: 220/371
• CPC Class Codes: B65D 21/0222 the closure and the bottom presenting co-operating peripheral ribs and grooves
• CPC Class Codes: B65D 2205/02 Venting holes
• CPC Class Codes: B65D 2251/0018 of the 43-type
• CPC Class Codes: B65D 2251/0093 Membrane
• CPC Class Codes: B65D 2543/00194 square or rectangular with curved sides B65D2543/00101
• CPC Class Codes: B65D 2543/00296 Plastic
• CPC Class Codes: B65D 51/1611 by means of an orifice, capillary or labyrinth passage B65D51/1616, B65D51/1622 take precedence
• CPC Class Codes: B65D 51/20 Caps, lids, or covers co-operating with an inner closure arranged to be opened by piercing, cutting, or tearing B65D51/185 takes precedence; co-operating with an auxiliary container for additional articles or materials B65D51/28
• CPC Class Codes: B65D 81/263 for ventilating the contents B65D5/4295, B65D51/1605 take precedence

Abstract

A package for maintaining a modified atmosphere around contents being contained therein when stored in an ambient environment is set forth. The modified-atmosphere package includes a tray, a membrane, and a structural member. The tray has a base and side walls extending upwardly from the base. The side walls and the base define a cavity wherein the contents are disposed. A membrane is attached to a top portion of the side walls and encloses the cavity. The structural member is detachably connected to the top portion of the side walls and is disposed above the membrane to prevent the membrane from contacting an external structure which inhibits permeation through the membrane. The structural member also has at least one opening for exposing the membrane to the ambient environment. Stacking means at the base of the tray and the top of the structural member allow the modified-atmosphere packages to be easily stacked. A vented-environment package is also shown which is very similar to the modified-atmosphere package except the permeable membrane is absent and the tray has at least one opening at its base. This opening on the lid is at least partially aligned with the base opening on the tray and simultaneously exposed to the ambient environment when two vented-environment packages are stacked. The lids utilized on the vented-environment package and the modified-atmosphere package are interchangeable.

Claims

1. A package for maintaining a modified atmosphere around food contents being contained therein when stored in an ambient environment, said modified-atmosphere package comprising:

a tray having a base and side walls extending upwardly from said base, said side walls and said base defining a cavity for receiving said food contents, said side walls including a top portion, said tray being a unitary member;

a membrane attached to said top portion of said side walls and enclosing said cavity, said membrane having an upper surface facing away from said cavity, said upper surface above said cavity being free of contact from any structure above said cavity; and

a structural member detachably connected to said top portion of said side walls, said structural member being disposed above said membrane to prevent said membrane from contacting an external structure, said structural member having at least one opening for exposing said membrane to said ambient environment, said structural member being a unitary member.

2. The modified-atmosphere package of claim 1, wherein said structural member includes a lid, said top portion of said side walls defining a periphery and said lid being detachably connected to a substantial portion of said periphery.

3. The modified-atmosphere package of claim 2, wherein an upper segment of said lid has a first stacking means and said base of said tray has a second stacking means, said first stacking means being engageable with said second stacking means, said first and second stacking means providing for stacking of said modified-atmosphere package with a second modified-atmosphere package.

4. The modified-atmosphere package of claim 1, wherein said structural member has a first stacking means and said base of said tray has a second stacking means, said first stacking means being engageable with said second stacking means, said first and second stacking means providing for stacking of said modified-atmosphere package with a second modified-atmosphere package.

5. The modified-atmosphere package of claim 4, wherein said first stacking means includes a downwardly projecting recess and said second stacking means includes a downwardly projecting member.

6. The modified-atmosphere package of claim 1, wherein said unitary structural member and said unitary tray are free of a hinged connection.

7. The modified-atmosphere package of claim 1, wherein said tray and said structural member are made of materials selected from the group consisting of polystyrene, polyester, and polypropylene.

8. The modified-atmosphere package of claim 1, wherein a region between said structural member and said membrane contains only air.

9. The modified-atmosphere package of claim 1, wherein said membrane is made of a material selected from the group consisting of polystyrene, polyethylene and polypropylene.

10. The modified-atmosphere package of claim 1, wherein said upper surface is unobstructedly exposed to a lower surface of said structural member.

11. The modified-atmosphere package of claim 1, wherein said membrane is a permeable film configured to limit the exchange of gases between said cavity and said ambient environment.

12. The modified-atmosphere package of claim 1, wherein said membrane is sandwiched between said top portion of said side walls and said structural member.

13. The modified-atmosphere package of claim 1, wherein said membrane is a film of polyethylene in combination with at least one of polyvinylidene chloride and ethylene vinyl alcohol for significantly reducing the exchange of gases between said cavity and said ambient environment.

14. An arrangement for maintaining a controlled environment around packaged food contents stored in an ambient environment, said arrangement comprising:

lower and upper vented-environment packages, each of said lower and upper vented-environment packages including;

a tray having a base and side walls extending upwardly from said base, said side walls and said base defining a cavity wherein food said contents are disposed, said base having a first opening and a first stacking means; and

a lid detachably connected to a top portion of said side walls, said lid having a second opening and a second stacking means,

wherein said lower vented-environment package and said upper vented-environment package are stackable when the first stacking means of said upper vented-environment package engages the second stacking means of said lower vented-environment package, the second opening on the lid of said lower vented-environment package being at least partially aligned with and directly adjacent to the first opening on said base of said upper vented-environment package and being simultaneously exposed to said ambient environment when said lower and upper vented-environment packages are stacked.

15. The vented-environment packages of claim 14, wherein said first opening is smaller than said second opening.

16. The vented-environment packages of claim 14, wherein said first stacking means includes a downwardly projecting member and said second stacking means includes a downwardly projecting recess.

17. The vented-environment packages of claim 14, wherein said first opening is adjacent an edge where one of said side walls meets said base.

18. The vented-environment packages of claim 17, wherein said one of said side walls of said upper vented-environment package includes an indentation extending inwardly toward said cavity adjacent said first opening, said indentation exposing said second opening on said lid of said lower vented-environment package to said ambient environment when said upper and lower vented-environment packages are stacked.

19. The vented-environment packages of claim 14, wherein said tray is made of a material selected from the group consisting of polystyrene, polyester, and polypropylene.

20. The vented-environment packages of claim 14, wherein said lid is made of a material selected from the group consisting of polystyrene, polyester, and polypropylene.

21. The vented-environment packages of claim 14, wherein portions of said base near said first opening are contacting portions of said lid near said second opening.

22. A food package for maintaining a modified atmosphere around perishable food contents contained therein when said food package is stored in an ambient environment, said food package comprising:

a tray having a base and side walls extending upwardly from said base, said side walls and said base defining a cavity;

perishable food disposed within said cavity;

a membrane attached to a top portion of said side walls and enclosing said perishable food within said cavity; and

a structural member detachably connected to said top portion of said side walls, said structural member being disposed above said membrane to prevent contact with an upper surface of said membrane, a region between said membrane and said structural member containing only air, said structural member forming a passageway to provide for communication between said region and said ambient environment.

23. The food package of claim 22, wherein an upper surface of said membrane is unobstructedly exposed to a lower surface of said structural member.

24. The food package of claim 22, wherein said membrane has an upper surface which is free of contact any structure above said cavity.

25. The food package of claim 22, wherein an upper segment of said structural member has a first stacking means and said base of said tray has a second stacking means, said first stacking means being engageable with said second stacking means, said first and second stacking means providing for stacking of said food package with a second food package, wherein said at least one opening is at least partially unobstructed when said first and second stacking means are engaged.

26. The food package of claim 22, wherein said tray is a unitary member and said structural member is a unitary member.

27. The food package of claim 22, wherein said membrane is a permeable film configured to limit the exchange of gases between said cavity and said ambient environment.

28. The food package of claim 22, wherein said membrane is sandwiched between said top portion of said side walls and said structural member.

29. The food package of claim 22, wherein said membrane is a film of polyethylene in combination with at least one of polyvinylidene chloride and ethylene vinyl alcohol for significantly reducing the exchange of gases between said cavity and said ambient environment.

30. An arrangement for maintaining a controlled environment around packaged contents stored in an ambient environment, said arrangement comprising:

a first tray having a first base and first side walls extending upwardly from said first base, said first side walls and said first base defining a first cavity, said first base having a first opening and a first stacking means;

a first group of perishable food disposed within said first cavity;

a first lid detachably connected to a top portion of said first side walls, said first tray, said first group of perishable food and said first lid being an upper package;

a second tray having a second base and second side walls extending upwardly from said second base, said second side walls and said second base defining a second cavity,

a second group of perishable food disposed within said second cavity;

a second lid detachably connected to a top portion of said second side walls;

said second lid having a second opening and a second stacking means, said second tray, said second group of perishable food and said second first lid being a lower package;

wherein said lower said upper packages are stackable when said first stacking means and second stacking means are engaged, said second opening on said lid of said lower package being at least partially aligned with and adjacent to said first opening on said first base of said upper package and being simultaneously exposed to said ambient environment when said lower and upper packages are stacked.

31. The arrangement of packages of claim 30 wherein said first opening is adjacent an edge where one of said first side walls meets said first base.

32. The arrangement of packages of claim 31, wherein said one of said first side walls of said upper package includes an indentation extending inwardly toward said first cavity adjacent said first opening, said indentation exposing said second opening on said second lid of said lower package to said ambient environment when said upper and lower packages are stacked.

33. A package for maintaining a modified atmosphere around food contents, comprising:

a tray having a base and at least one wall extending upwardly from said base, said at least one wall and said base defining a cavity for receiving said food contents;

a membrane contacting said at least one wall and enclosing said cavity;

a lid connected to said at least one wall, said lid and said membrane being separated from each other and defining a continuous gap therebetween above said cavity; and

means for venting gases from said gap to an ambient environment.

34. The modified-atmosphere package of claim 33, wherein said membrane only contacts said lid directly adjacent to said at least one wall.

35. The modified-atmosphere package of claim 33, wherein said venting means is located on said lid.

36. The modified-atmosphere package of claim 33, wherein said venting means includes at least one opening.

37. The modified-atmosphere package of claim 33, wherein said venting means is located adjacent to a periphery of said lid.

38. The modified-atmosphere package of claim 37, wherein said venting means includes at least one opening.

39. The modified-atmosphere package of claim 33, wherein said venting means is located adjacent to said at least one wall of said tray.

40. The modified-atmosphere package of claim 39, wherein said venting means includes at least one opening in said lid above said at least one wall.

41. The modified-atmosphere package of claim 33, wherein said tray has an outwardly extending flange and said lid has a mating structure for detachable connection to said flange, said venting means being located in a region where said mating structure and said flange are detachably connected.

42. The modified-atmosphere package of claim 33, wherein tray has a generally polygonal periphery.

43. The modified-atmosphere package of claim 33, wherein said tray is a unitary member and said structural member is a unitary member.

44. The modified-atmosphere package of claim 33, wherein said membrane is a permeable film configured to limit the exchange of gases between said cavity and said ambient environment.

45. The modified-atmosphere package of claim 33, wherein said membrane is sandwich between said side walls and said lid.

46. The modified-atmosphere package of claim 33, wherein said membrane is a film of polyethylene in combination with at least one of polyvinylidene chloride and ethylene vinyl alcohol for significantly reducing the exchange of gases between said cavity and said ambient environment.

47. A package for maintaining a modified atmosphere around food contents, comprising:

a tray having a base and at least one wall extending upwardly from said base, said at least wall and said base defining a cavity for receiving said food contents;

a membrane contacting said at least one wall and enclosing said cavity;

a lid connected to said at least one wall, said lid and said membrane being separated from each other and defining a continuous gap therebetween above said cavity; and

a passageway in communication with said gap adapted to replenish gases within said gap with gases from an ambient environment.

48. The modified-atmosphere package of claim 47, wherein said passageway is formed by material of said lid.

49. The modified-atmosphere package of claim 48, wherein said passageway is an opening in said material of said lid.

50. The modified-atmosphere package of claim 47, wherein said membrane is a permeable film configured to limit the exchange of gases between said cavity and said ambient environment.

51. The modified-atmosphere package of claim 47, wherein said tray is a unitary member and said structural member is a unitary member.

52. A package for maintaining a modified atmosphere around food contents, comprising:

a tray having a base and at least one wall extending upwardly from said base, said at least one wall and said base defining a cavity for receiving said food contents;

a membrane contacting said at least one wall and enclosing said cavity; and

a lid connected to said at least one wall, said lid being separated from said membrane by a gap to prevent contact with a substantial portion of an upper surface of said membrane, said lid having a lid stacking element for mating with a corresponding stacking element of a package positioned thereabove, said lid being constructed such that said gap is in communication with an ambient environment when said lid stacking element mates with said corresponding stacking element.

53. The modified-atmosphere package of claim 52, wherein said membrane is sandwich between said side walls and said lid.

54. The modified-atmosphere package of claim 52, wherein said gap communicates with said ambient environment near a periphery of said lid.

55. The modified-atmosphere package of claim 52, wherein said gap communicates with said ambient environment through an opening formed in said lid.

56. The modified-atmosphere package of claim 52, wherein said upper surface of said membrane is unobstructedly exposed to a lower surface of said lid.

57. The modified-atmosphere package of claim 53, wherein said upper surface is free of contact from any structure above said cavity.

58. A method of maintaining a modified atmosphere around food contents disposed in a tray, comprising:

placing said food contents in said tray;

providing a predetermined mixture of gases within said tray;

sealing said tray with a permeable membrane capable of limiting the flow of specific gases from a lower surface of said membrane exposed to said food contents to an upper surface of said membrane;

inhibiting contact with a substantial portion of said upper surface of said membrane; and

venting said specific gases released from said upper surface of said membrane to an ambient environment.

59. The method of claim 58, wherein said inhibiting contact with said upper surface includes attaching a structural member to said tray, said structural member being above said upper surface of said membrane.

60. The method of claim 59, wherein said venting said specific gases includes forming said structural member to provide said specific gases with a path to said ambient environment when said structural member is attached to said tray.

61. The method of claim 60, wherein said forming said structural member includes producing at least one opening in the material of said structural member.

62. The method of claim 59, wherein said specific gases include byproduct gases produced by said food contents.