Tamper-evident push-through packaging
The present invention relates to a tamper-evident push-through packaging secured against fraudulent reuse comprising: —a polymer base web ( 1 ) comprising at least one pocket; —a multilayer lidding film ( 2 ) covering said pocket, said multilayer lidding film ( 2 ) comprising on its seal side a coextruded polymer film, said coextruded polymer film comprising a push-through polymer layer ( 3 ) sealed on the base web by a permanent seal and a peelable protective polymer layer ( 4 ), the polymers of both layers ( 3,4 ) being incompatible and in direct contact with each other, without interlayer, the adhesion between said push-through polymer layer ( 3 ) and said peelable protective polymer layer ( 4 ) being lower than the seal strength between said polymer base web ( 1 ) and said push-through polymer layer ( 3 ), wherein, in use, the push-trough layer leaves a seal seam ( 6 ), after removing the part of the push-trough layer ( 3 ) covering the pocket and wherein said protective layer ( 4 ) cannot be resealed by a heat sealing process on said seal seam ( 6 ).
1. Tamper-evident push-through packaging secured against fraudulent reuse comprising: —a polymer base web ( 1 ) comprising at least one pocket;
a multilayer lidding film ( 2 ) covering said at least one pocket, said multilayer lidding film ( 2 ) comprising on a seal side thereof a coextruded polymer film, said coextruded polymer film comprising a push-through polymer layer ( 3 ) sealed on the base web by a permanent seal and a peelable protective polymer layer ( 4 ), the polymers of both layers ( 3 , 4 ) being incompatible and in direct contact with each other, without an interlayer, the adhesion between said push-through polymer layer ( 3 ) and said peelable protective polymer layer ( 4 ) being lower than the seal strength between said polymer base web ( 1 ) and said push-through polymer layer ( 3 ), wherein, in use, the push-through layer leaves a seal seam ( 6 ), after removing the part of the push-through layer ( 3 ) covering the at least one pocket and wherein said protective layer ( 4 ) cannot be resealed by a heat sealing process on said seal seam ( 6 ).
2. A tamper-evident push-through packaging according to claim 1 , wherein said multilayer lidding film ( 2 ) comprises at least one additional layer.
3. A tamper-evident push-through packaging according to claim 2 , wherein said at least one additional layer is selected from the group consisting of paper, metal and polymer.
4. A tamper-evident push-through packaging according to claim 1 , wherein the adhesion between said push-through layer ( 3 ) and said protective layer ( 4 ) is between 0.3N/15 mm and 3.5N/15 mm measured according to ASTM F88-00.
5. A tamper-evident push-through packaging according to claim 1 , wherein the puncture resistance of the push-through layer ( 3 ) is between 0.6 N and 7 N, measured according to ASTM F1306-90.
6. A tamper-evident push-through packaging according to claim 1 , wherein the puncture resistance of the push-through layer ( 3 ) is between 1.4 N and 4 N, measured according to ASTM F1306-90.
7. A tamper-evident push-through packaging according to claim 1 , wherein the thickness of the push-through layer ( 3 ) is lower than 20 μm.
8. A tamper-evident push-through packaging according to claim 1 , wherein the thickness of the push-through layer ( 3 ) is lower than 15 μm.
9. A tamper-evident push-through packaging according to claim 1 , wherein the combinations of the incompatible polymers of the push-through polymer layer ( 3 ) and the peelable protective polymer layer ( 4 ) are selected from the group consisting of PETG and PP block copolymer; PETG and LDPE; ethylene-propylene block copolymer and PETG; MDPE and PP; MDPE and PETG; and EMA and PA.
10. A tamper-evident push-through packaging according to claim 1 , wherein the push-through polymer layer ( 3 ) comprises inorganic filler.
11. A tamper-evident push-through packaging according to claim 1 , wherein the push-through polymer layer ( 3 ) has another colour or aspect than the protective polymer layer ( 4 ); or another colour and aspect than the protective polymer layer ( 4 ).
12. A tamper-evident push-through packaging according to claim 1 , wherein the compatibility between the polymers of the push-through layer ( 3 ) and the base web ( 1 ) ensures the presence of a permanent seam ( 6 ) permanently sealed onto the base web ( 1 ) even after removing the part of the push-through layer covering the at least one pocket.