Packaging with peelable lid
First Claim
1. A method of sealing a peelable lid to a package which contains a base and a flexible web of plastics material covering and held to the base at the perimeter thereof which together define a space therebetween, said method comprising the steps of:
- placing said lid over said flexible web;
sealing said lid by a thermosealing process to said flexible web over said base with a strip seal which extends around the perimeter of said base, said seal having an inner portion and an outer portion, said thermosealing process providing a temperature gradient across the width of the striplike seal from the inner portion to the outer portion thereof,said seal further having a peelable adhesion gradient across the width of said strip seal, the inner portion of the seal which is adjacent the space having an adhesion which is lower than the adhesion of the outer portion of said seal so that when said lid is stripped from said package, said flexible web is unlikely to rupture.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of sealing a peelable lid (7) to a package is disclosed. The package contains a base (1) and a potentially rupturable flexible web (5) of plastics material covering the base (1) which together define a sealed space therebetween. The lid (7) is in turn sealed above the flexible web (5). The method comprises the steps of: 1) placing a lid (7) over a thin flexible web (5); 2) sealing the lid (7) to the thin flexible web (5) over the base (1) with a strip like seal (13) which extends around the perimeter of the space so the lid (7) will be sealed at the same region as the thin flexible web (5) is sealed to the base (1). The sealing is achieved by a thermosealing process which provides a temperature gradient across the width provides the seal (13) with a peelable adhesion gradient across its width so that when the lid (7) is stripped from the package, it will be unlikely to rupture the thin flexible web (5). A package made by the method is also disclosed.
90 Citations
42 Claims
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1. A method of sealing a peelable lid to a package which contains a base and a flexible web of plastics material covering and held to the base at the perimeter thereof which together define a space therebetween, said method comprising the steps of:
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placing said lid over said flexible web; sealing said lid by a thermosealing process to said flexible web over said base with a strip seal which extends around the perimeter of said base, said seal having an inner portion and an outer portion, said thermosealing process providing a temperature gradient across the width of the striplike seal from the inner portion to the outer portion thereof, said seal further having a peelable adhesion gradient across the width of said strip seal, the inner portion of the seal which is adjacent the space having an adhesion which is lower than the adhesion of the outer portion of said seal so that when said lid is stripped from said package, said flexible web is unlikely to rupture. - View Dependent Claims (2, 3, 4)
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- 5. A package comprising a base, a flexible web of plastics material covering said base and adhered to said base to define a space therebetween, and a lid sealed to said flexible web at the same region as said flexible web is adhered to said base, the sealing of said lid to said flexible web being by way of a strip seal having an inner portion and an outer portion which extends around said base, and wherein there is a peelable adhesion gradient across the width of the strip, the inner portion of the strip seal being adjacent the space and having a lower adhesion than the outer portion thereof, such that, said flexible web is inhibited against rupturing when said lid is peeled from said package.
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11. Apparatus for sealing a peelable lid to a package which contains a base and a flexible web of plastics covering and held to the base which together define a space therebetween for receipt of goods, said base having a cup shaped depression on which said goods are received and a peripheral lip surrounding said cup shaped depression,
said apparatus comprising a lower chamber part to receive said base and said flexible web, platen means for heat sealing said lid to said flexible web and to cause adhesion of said flexible web to said lip, said platen forming a sealing strip surface around said depression and alignable with said lip, said sealing strip having an inner portion and an outer portion; -
means for heating said platen so said sealing strip surface has a temperature gradient thereacross, such that a higher temperature is applied at the outer portion of said sealing strip surface; and means for moving said platen means to effect such sealing and adhesion. - View Dependent Claims (12, 13)
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14. A method of sealing a peelable lid to a package which contains a base and a flexible web of plastics material covering and held to the base at the perimeter thereof which together define a space therebetween, said method comprising the steps of:
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placing said lid over said flexible web; sealing said lid by a thermosealing process to said flexible web over said base with a strip seal by applying a heated platen to the lid and effecting a thermo sealing adhesion, said strip seal having an inner portion and an outer portion and extending around the perimeter of said base, said thermosealing process providing a temperature gradient across the width of the strip like seal from the inner portion to the outer portion thereof, said seal further having a peelable adhesion gradient across the width of said strip seal, the inner portion of the seal which is adjacent the space having an adhesion which is lower than the adhesion of the outer portion of said seal so that when said lid is stripped from said package, said flexible web is unlikely to rupture.
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15. A method of producing a gas barrier package which comprises a first gas barrier web, a gas permeable web of plastics material covering and held to the first gas barrier web to define a goods containing space therebetween, and a second gas barrier web covering said gas permeable web and peelably sealed relative to said first gas barrier web to define a gas barrier packaging containing said goods, said method having the steps of:
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sealing said gas permeable web to said first gas barrier web with a first strip seal which extends around said space and closes said space containing goods; sealing said second gas barrier web relative to said first gas barrier web by a second strip seal which is peelable and which extends around said first gas barrier web external of said first strip seal to define said gas barrier package; so that when said second gas barrier web is peeled to open said gas barrier package, said first strip seal remains intact and retains said gas permeable web sealed to said first gas barrier web with goods therebetween, such that gas can permeate said gas permeable web and contact said goods. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A gas barrier package comprising
a first gas barrier web and a gas permeable web of plastics material covering and sealed to said first gas barrier web to define a goods containing space therebetween; -
a second gas barrier web covering said gas permeable web; a first strip seal sealing the gas permeable web to the first gas barrier web, said first strip seal extending around and closing said space; and a second strip seal sealing said second gas barrier web relative to said first barrier web, said second strip seal being peelable and extending around said first gas barrier web external of said first strip seal, said second seal having a higher adhesion gradient than said first seal, such that when said second gas barrier web is peeled to open said gas barrier package, said first strip seal remains intact and retains said gas permeable web sealed to said first gas barrier web with goods therebetween, and wherein gas can permeate said gas permeable web to then contact said goods. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29)
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30. Apparatus for producing a gas barrier package comprising a first gas barrier web and a gas permeable web of plastics material covering and held to the first gas barrier web to define goods containing space therebetween, and a second gas barrier web covering said gas permeable web and peelably sealed relative to said first gas barrier web, said first gas barrier web having a cup shaped depression therein in which said goods are received and a peripheral lip surrounding said cup shaped depression, said apparatus comprising:
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sealing means for providing a first strip seal between said gas permeable web and said first gas barrier web, said first strip seal extending around said space and closing said space, said sealing means also providing a second strip seal for sealing said second gas barrier web relative to said first gas barrier web with a peelable seal, said second strip seal extending around said first gas barrier web external of said first strip seal and having a higher adhesion gradient than said first seal, such that when said second gas barrier web is peeled to open said gas barrier package, said first strip seal remains intact and retains said gas permeable web sealed to said first gas barrier web with goods therebetween, and wherein gas can permeate said gas permeable web to then contact said goods. - View Dependent Claims (31, 32, 33, 34)
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35. A gas barrier package comprising
a first gas barrier web and a gas permeable web of plastics material covering and sealed to said first gas barrier web to define a goods containing space therebetween; -
a second gas barrier web covering said gas permeable web; a first strip seal sealing the gas permeable web to the first gas barrier web, said first strip seal extending around and closing said space; and a second strip seal sealing said second gas barrier web relative to said first barrier web, said second strip seal having a higher adhesion gradient than said first seal and being peelable and extending around said first gas barrier web adjacent to said first strip seal; such that when said second gas barrier web is peeled to open said gas barrier package, said first strip seal remains intact and retains said gas permeable web sealed to said first gas barrier web with goods therebetween, and wherein gas can permeate said gas permeable web to then contact said goods. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42)
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Specification