Inner seal with a sub tab layer
A pull-tab sealing member for a container containing an upper laminate forming a pull-tab bonded to a lower laminate capable of being heat sealed to a container's mouth or opening. The upper laminate defines the pull tab wholly within a perimeter or circumference of the seal. The sealing member further includes a sub tab layer or member under the gripping tab for structural support.
1. A concentrically stable tabbed sealing member for sealing to a rim surrounding a container opening, the sealing member formed out of a multi-layer laminate sheet comprising:
a lower laminate portion including a heat seal layer for bonding to the container rim, a metal foil layer above the heat seal layer for heating the heat seal layer, a polymer foam layer above the metal foil layer, and at least one non-foam polyolefin film support layer above the polymer foam layer;
an upper laminate portion including one or more layers and partially bonded to the lower laminate portion and including a free portion not bonded to the at least one non-foam polyolefin film support layer;
a tab stock polymer layer extending partway across the concentrically stable tabbed sealing member, the tab stock polymer layer bonded to one of the layers in the upper laminate portion and not bonded to the lower laminate portion, wherein the free portion and the tab stock polymer layer form a gripping tab defined wholly within a perimeter of the sealing member, the gripping tab for removing the sealing member from a container opening; and
the at least one non-foam polyolefin film support layer coextensive with at least the gripping tab at a periphery thereof to provide structural support and stabilize the lower laminate portion below the gripping tab of the sealing member.
2. The sealing member of claim 1 , wherein the at least one non-foam polyolefin film support layer is bonded to the polymer foam layer and not bonded to the free portion forming the gripping tab.
3. The sealing member of claim 1 , wherein the at least one non-foam polyolefin film support layer is bonded to the polymer foam layer and not bonded to the tab stock polymer layer.
4. The sealing member of claim 1 , wherein the at least one non-foam polyolefin film support layer is about 1 to about 5 mils thick.
5. The sealing member of claim 1 , wherein the polymer foam layer has an internal rupture strength of about 2,000 to about 3,500 grams per inch.
6. The sealing member of claim 1 , wherein the polymer foam layer has a density of about 0.4 to about 0.6 grams per cubic centimeter.
7. The sealing member of claim 1 , wherein the upper laminate portion includes a heat activated bonding layer forming the at least partial bond to the lower laminate portion.
8. The sealing member of claim 7 , wherein the heat activated bonding layer is selected from the group consisting of ethylene vinyl acetate, polyolefin, two-component polyurethane, ethylene acrylic acid copolymers, curable two-part urethane adhesives, epoxy adhesives, ethylene methacrylate copolymers, and combinations thereof.
9. The sealing member of claim 1 , wherein the at least one non-foam polyolefin film support layer is coextensive with the upper laminate and the partial bond of the upper laminate portion to the lower laminate portion is to the non-foam polyolefin film support layer.
10. A laminate for forming a concentrically stable tabbed sealing member for sealing to a rim surrounding a container opening, the laminate comprising:
a lower laminate portion including a heat seal layer for bonding to a container rim when the laminate is formed into the concentrically stable stabbed sealing member, a metal foil layer above the heat seal layer for heating the heat seal layer, a polymer foam layer above the metal foil layer, and at least one non-foam polyolefin film support layer above the polymer foam layer;
an upper laminate portion including one or more layers and partially bonded to the lower laminate portion and including a free portion not bonded to the at least one non-foam polyolefin film support layer for forming a gripping tab when the laminate is formed into the concentrically stable tabbed sealing member;
the at least one non-foam polyolefin film support layer to provide structural support and stabilize the lower laminate portion below the free portion when the laminate is formed into the concentrically stable tabbed sealing member; and
a tab stock polymer layer extending partway across the upper laminate portion, the tab stock polymer layer bonded to one of the layers in the upper laminate portion and not bonded to the lower laminate portion.
11. The laminate of claim 10 , wherein the at least one non-foam polyolefin film support layer is bonded to the polymer foam layer and not bonded to the free portion.
12. The laminate of claim 10 , wherein the at least one non-foam polyolefin film support layer is bonded to the polymer foam layer and not bonded to the tab stock polymer layer.
13. The laminate of claim 10 , wherein the at least one non-foam polyolefin film support layer is about 1 to about 5 mils thick.
14. The laminate of claim 10 , wherein the polymer foam layer has an internal rupture strength of about 2,000 to about 3,500 grams per inch.
15. The laminate of claim 10 , wherein the polymer foam layer has a density of about 0.4 to about 0.6 grams per cubic centimeter.
16. The laminate of claim 10 , wherein the upper laminate portion includes a heat activated bonding layer forming the at least partial bond to the lower laminate portion.
17. The laminate of claim 16 , wherein the heat activated bonding layer is selected from the group consisting of ethylene vinyl acetate, polyolefin, two-component polyurethane, ethylene acrylic acid copolymers, curable two-part urethane adhesives, epoxy adhesives, ethylene methacrylate copolymers, and combinations thereof.
18. The laminate of claim 10 , wherein the at least one non-foam polyolefin film support layer is coextensive with the upper laminate and the partial bond of the upper laminate portion to the lower laminate portion is to the non-foam polyolefin film support layer.