Sealing element for vessel or container closures having improved barrier properties
Described is a closure element for a container. The closure elements has a sealing element which contains a thermoplastic polymer, and an effective absorbing amount of an unmodified cyclodextrin material. The unmodified cyclodextrin material may be an α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and mixtures thereof. The sealing element can act as a barrier with respect to permeants, such as aromatic substances, trichloroanisole, aldehydes or ketones and/or impurities from the polymer.
1. A closure for an aperture of a beverage bottle, comprising:
a cap having an inner side; the cap selected from the group consisting of a twist crown, a crown cork and a screw cap; and
a sealing element situated on an inner side of the cap which, in use substantially faces the beverage bottle, the sealing element being tightly fitted onto the aperture by a pressure from the cap to seal the aperture, the sealing element including (a) an extrudable thermoplastic polymer and (b) an effective absorbing amount of an unmodified cyclodextrin material,
wherein the unmodified cyclodextrin material is selected from the group consisting of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and mixtures thereof; and
wherein the unmodified cyclodextrin material is dispersed in the thermoplastic polymer.
2. The closure of claim 1 , wherein the thermoplastic polymer comprises a polyolefine.
3. The closure of claim 1 , wherein the thermoplastic polymer comprises a high density polyethylene (HDPE).
4. The closure of claim 1 , wherein the amount of unmodified cyclodextrin material in the sealing element is in the range between 0.01 and 5 wt-%, based on the weight of the thermoplastic polymer in the sealing element.
5. The closure of claim 1 , wherein the amount of unmodified cyclodextrin material in the sealing element is in the range between 0.1 and 1 wt-%, based on the weight of the thermoplastic polymer in the sealing element.
6. The closure of claim 1 , wherein the sealing element includes a heterogeneous blend of the thermoplastic polymer and a rubber component.
7. The closure of claim 1 , wherein the sealing element includes a heterogeneous blend of the thermoplastic polymer and butyl rubber, wherein the thermoplastic polymer is a high-density polyethylene.
8. The closure of claim 1 , wherein the sealing element includes a first layer and at least one additional layer containing the thermoplastic polymer and an effective absorbing amount of the unmodified cyclodextrin material.
9. The closure of claim 8 , wherein the sealing element is situated on the inner side of the cap and wherein the at least one additional layer is arranged on the inner side of the cap, substantially facing the beverage bottle.
10. The closure of claim 8 , wherein the at least one additional layer fits into the aperture of the beverage bottle and does not extend to an area clamped between an edge of the aperture and the closure.
11. The closure of claim 1 , wherein the sealing element is a laminate.
12. The closure of claim 1 , wherein the sealing element is extruded thermoplastic polymer containing the effective absorbing amount of a cyclodextrin material.
13. The closure of claim 1 , wherein the thermoplastic polymer comprises one of a butyl rubber and a polypropylene.