Extrusion-Coated Lidding Foil For Push-Through Blister Packaging

Abstract

An extrusion-coated lidding foil for blister packaging particularly suitable for push-through pharmaceutical and food blister packaging. The lidding foil includes a foil layer on which one or more tie layer and one or more sealant layer, one or both of which include an embrittling agent mixed therein, are extrusion coated resulting in a lidding foil having push-through ability. The push-through ability of the lidding foil is characterized by a Mullen burst strength of about 10 psi to about 30 psi and an MD tear strength of about 30 to about 100 grams-force.

1 . A push-through blister packaging comprising:
 a. a lidding foil comprising:
 i. an aluminum foil; and 
 ii. one or more tie layer comprising ethylene acid copolymer extrusion coated on said aluminum foil and one or more sealant layer comprising modified ethylene acrylate copolymer extrusion coated on said tie layer, one or both of said tie and sealant layers having an embrittling agent mixed therein in an amount of about 5 to about 50% by weight; 
   wherein said lidding foil is characterized by a Mullen burst strength of about 50 kPa to about 250 kPa and a MD tear strength of about 0.25 N to about 1.0 N; and   b. a polymeric blister film,   wherein said lidding foil is heat sealed to said blister film to form said push-through blister packaging containing a substance which may be retrieved from said packaging by pushing the substance against and breaking said lidding foil.   
     
     
         2 . The lidding foil of  claim 1  wherein said embrittling agent is mixed in one or both of said tie and sealant layers in an amount of about 10 to about 30% by weight. 
     
     
         3 . The lidding foil of  claim 1  wherein said embrittling agent is a mineral. 
     
     
         4 . The lidding foil of  claim 3  wherein said embrittling agent is one or more of:
 a. calcium carbonate; 
 b. calcium sulfate; 
 c. glass fiber; 
 d. kaolin; 
 e. mica; 
 f. silica 
 g. talc 
 h. wollastonite; and 
 i. a mixture of two or more of a-h. 
 
     
     
         5 . The lidding foil of  claim 1  wherein said embrittling agent is equally distributed within said sealant layer. 
     
     
         6 . The lidding foil of  claim 1  wherein said embrittling agent is non-equally distributed within said sealant layer, said embrittling agent being more concentrated within a portion of said sealant layer that is adjacent to said tie layer. 
     
     
         7 . The lidding foil of  claim 1  wherein said aluminum foil has a thickness of about 20 μm to about 25 μm. 
     
     
         8 . The lidding foil of  claim 1  wherein said aluminum foil is hard tempered (unannealed). 
     
     
         9 . The lidding foil of  claim 1  wherein said aluminum foil is soft tempered (annealed). 
     
     
         10 . The lidding foil of  claim 1  wherein said one or more tic layer is coated on said foil in an amount of about 3 to about 8 g/m 2 , and said one or more sealant layer is coated on said tie layer in an amount of about 6 to about 16 g/m 2 . 
     
     
         11 . A push-through blister packaging comprising:
 a. a lidding foil comprising:
 i. an aluminum foil; 
 ii. one or more tie layer comprising ethylene acid copolymer extrusion coated on said aluminum foil and one or more sealant layer comprising modified ethylene acrylate copolymer extrusion coated on said tie layer, one or both of said tie and sealant layers having an embrittling agent mixed therein in an amount of about 5 to about 50% by weight; 
   wherein said tie layer is extrusion coated to a coatweight of about 3 to about 8 g/m 2  and said sealant layer is extrusion coated to a coatweight of about 6 to about 16 g/m 2 .; and   b. a polymeric blister film,   wherein said lidding foil is heat sealed to said blister film to form said push-through blister packaging containing a substance which may be retrieved from said packaging by pushing the substance against and breaking said lidding foil.   
     
     
         12 . The lidding foil of  claim 11  wherein said lidding foil is characterized by a Mullen burst strength of about 50 kPa to about 250 kPa and a MD tear strength of about 0.25 N to about 1.0 N. 
     
     
         13 . The lidding foil of  claim 11  wherein said embrittling agent is mixed in one or both of said tie and sealant layers in an mount of about 10 to about 30% by weight. 
     
     
         14 . The lidding foil of  claim 11  wherein said embrittling agent is a mineral. 
     
     
         15 . The lidding foil of  claim 14  wherein said embrittling agent is one or more of:
 a. calcium carbonate; 
 b. calcium sulfate; 
 c. glass fiber; 
 d. kaolin; 
 e. mica; 
 f. silica 
 g. talc 
 h. wollastonite; and 
 i. a mixture of two or more of a-h. 
 
     
     
         16 . The lidding foil of  claim 11  wherein said embrittling agent is equally distributed within said sealant layer. 
     
     
         17 . The lidding foil of  claim 11  wherein said embrittling agent is non-equally distributed within said sealant layer, said embrittling agent being more concentrated within a portion of said sealant layer that is adjacent to said tie layer. 
     
     
         18 . The lidding foil of  claim 11  wherein said aluminum foil has a thickness of about 20 μm to about 25 μm. 
     
     
         19 . The lidding foil of  claim 11  wherein said aluminum foil is hard tempered (i.e. unannealed). 
     
     
         20 . The lidding foil of  claim 11  wherein said aluminum foil is soft tempered (i.e. annealed). 
     
     
         21 . A method of making a push-through blister packaging comprising the steps of:
 a. making a lidding foil comprising the steps of:
 i. providing an extrusion coating machine; 
 ii. providing a roll of aluminum foil on the extrusion coating machine; 
 iii. extrusion coating a tie layer comprising ethylene acid copolymer having a coatweight of about 3 to about 8 g/m 2  onto said aluminum foil; 
 iv. extrusion coating a sealant layer comprising modified ethylene acrylate copolymer having a coatweight of about 6 to about 16 g/m 2  onto said tie resin, one or both of said tie and sealant layers having an embrittling agent mixed therein in an amount of about 5 to about 50% by weight; 
   b. providing a polymeric blister film; and   c. sealing said lidding foil to said blister film containing a consumable substance and thereby forming said push-through blister packaging,   whereby said consumable substance may be retrieved from said blister packaging by pushing the consumable substance against and breaking said lidding foil open.   
     
     
         22 . The method of  claim 21  wherein said blister film comprises a polymer selected from the group consisting or PVC, PVDC, PS, HIPS, PCTFE, HDPE, LLDPE, LDPE, PP, PETG, SBC, COC, and combinations thereof. 
     
     
         23 . The method of  claim 22  wherein said blister film comprises polychlorotrifluoroethylene (PCTFE) 
     
     
         24 . The method of  claim 22  wherein said blister film comprises a cyclic olefin copolymer (COC). 
     
     
         25 . The method of  claim 21  further comprising the step of adding an embrittling agent mixed into one or both of said tie and sealant layers in an amount of about 5 to about 50% by weight. 
     
     
         26 . The method of  claim 25  wherein said embrittling agent is one or more of:
 a. calcium carbonate; 
 b. calcium sulfate; 
 c. glass fiber; 
 d. kaolin; 
 e. mica; 
 f. silica 
 g. talc 
 h. wollastonite; and 
 i. a mixture of two or more of a-h. 
 
     
     
         27 . The method of  claim 25  wherein said embrittling agent is equally distributed within said sealant layer. 
     
     
         28 . The method of  claim 25  wherein said embrittling agent is non-equally distributed within said sealant layer, said embrittling agent being more concentrated within a portion of said sealant layer that is adjacent to said tie layer. 
     
     
         29 . The method of  claim 21  wherein said tie layer and said sealant layer are simultaneously co-extruded onto the aluminum foil. 
     
     
         30 . The method of  claim 21  wherein said tie layer and said sealant layer are sequentially extrusion-coated onto the aluminum foil. 
     
     
         31 . The method of  claim 21  wherein said aluminum foil has a thickness of about 20 μm to about 25 μm.