Sealing Element for Vessel or Container Closures Having Improved Barrier Properties

Abstract

Described is a closure for a container. The closure element has a sealing element which contains a thermoplastic polymer; an effective absorbing amount of a cyclodextrin material; and at least one amide lubricant. The cyclodextrin material may be α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, derivatives of α-cyclodextrin, derivatives of β-cyclodextrin and derivatives of γ-cyclodextrin and mixtures thereof. The sealing element forms an effective barrier against volatile migrant contaminants, such as aromatic substances, trichloroanisole, aldehydes or ketones, and reduces the contamination with oxidative decomposition products resulting from the lubricant.

1 . A method of reducing oxidation of an unsaturated amide lubricant in a sealing element of a beverage bottle and providing an effective barrier against volatile migrant contaminants from entering an aperture of the beverage bottle, the method comprising:
 dispersing a cyclodextrin material having a cavity in a thermoplastic polymer, wherein the cyclodextrin material is selected from the group consisting of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, derivatives of α-cyclodextrin, derivatives of β-cyclodextrin and derivatives of γ-cyclodextrin and mixtures thereof;   complexing an unsaturated amide lubricant within the cavity of the cyclodextrin material dispersed in the thermoplastic material, thus providing a mixture of the thermoplastic polymer and an inclusion complex of the cyclodextrin material and the unsaturated amide lubricant;   forming a sealing element from the mixture;   placing the sealing element on an inner side of a beverage bottle cap; and   placing the beverage bottle cap over an aperture of a beverage bottle such that the sealing element is located at an interface between the beverage bottle cap and the beverage bottle;   wherein the inclusion complex of the cyclodextrin material and the unsaturated amide lubricant protects the unsaturated amide lubricant from oxidation reactions; and   wherein the cyclodextrin material complexes volatile migrant contaminants.   
     
     
         2 . The method of  claim 1 , further comprising the step of complexing decomposition compounds formed during the step of forming the sealing element in the cyclodextrin material. 
     
     
         3 . The method of  claim 1 , wherein the thermoplastic polymer is a heterogeneous blend of a butyl rubber phase and high density polyethylene (HDPE) phase. 
     
     
         4 . The method of  claim 3 , wherein the cyclodextrin material is dispersed in the high density polyethylene phase of the thermoplastic polymer. 
     
     
         5 . The method of  claim 3 , wherein the cyclodextrin material is dispersed in the butyl rubber phase of the thermoplastic polymer. 
     
     
         6 . The method of  claim 1 , wherein the cyclodextrin material is a γ-cyclodextrin having three acetyl groups per cyclodextrin unit. 
     
     
         7 . A method of reducing oxidation of an unsaturated amide lubricant in a sealing element of a beverage bottle and providing an effective barrier against volatile migrant contaminants from entering an aperture of the beverage bottle, the method comprising:
 providing a beverage bottle cap including a sealing element situated on an inner side of the beverage bottle cap, the sealing element including:
 a) a thermoplastic polymer, 
 b) a cyclodextrin material having a cavity dispersed in the thermoplastic polymer, and 
 c) an unsaturated amide lubricant dispersed in the thermoplastic polymer, 
 wherein the cyclodextrin material is selected from the group consisting of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, derivatives of α-cyclodextrin, derivatives of β-cyclodextrin and derivatives of γ-cyclodextrin and mixtures thereof; 
   forming an inclusion complex of the unsaturated amide lubricant in the cavity of the cyclodextrin material; and   sealing the aperture of the beverage bottle with the beverage bottle cap such that the sealing element is located at an interface between the beverage bottle cap and the beverage bottle;   wherein the inclusion complex of the cyclodextrin material and the unsaturated amide lubricant protects the unsaturated amide lubricant from oxidation reactions; and   wherein the cyclodextrin material complexes volatile migrant contaminants.   
     
     
         8 . The method of  claim 7 , wherein the cyclodextrin material includes pendant moieties or substituents that render the cyclodextrin material more compatible with the thermoplastic polymer. 
     
     
         9 . The method of  claim 7 , wherein the cyclodextrin material reduces the loss of flavors or flavoring substances from inside the beverage bottle. 
     
     
         10 . The method of  claim 7 , wherein the cyclodextrin material is a γ-cyclodextrin having three acetyl groups per cyclodextrin unit. 
     
     
         11 . A method of reducing oxidation of an unsaturated amide lubricant in a closure of a beverage bottle and providing an effective barrier against volatile migrant contaminants from entering an aperture of the beverage bottle, the method comprising:
 dispersing a cyclodextrin material having a cavity in a thermoplastic polymer, wherein the cyclodextrin material is selected from the group consisting of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, derivatives of α-cyclodextrin, derivatives of β-cyclodextrin and derivatives of γ-cyclodextrin and mixtures thereof;   complexing an unsaturated amide lubricant within the cavity of the cyclodextrin material dispersed in the thermoplastic material, thus providing a polymeric mixture of the thermoplastic polymer and an inclusion complex of the cyclodextrin material and the unsaturated amide lubricant;   forming a portion of the beverage bottle closure from the polymeric mixture; and   placing the beverage bottle closure over an aperture of a beverage bottle such that the aperture of the beverage bottle is covered by the beverage bottle closure;   wherein the inclusion complex of the cyclodextrin material and the unsaturated amide lubricant protects the unsaturated amide lubricant from oxidation reactions; and   wherein the cyclodextrin material complexes volatile migrant contaminants.   
     
     
         12 . The method of  claim 11 , wherein the cyclodextrin material is a γ-cyclodextrin having three acetyl groups per cyclodextrin unit. 
     
     
         13 . The method of  claim 11 , wherein the cyclodextrin material has a moisture content of less than 5,000 ppm by weight of the cyclodextrin material. 
     
     
         14 . The method of  claim 11 , wherein the cyclodextrin material has a moisture content of less than 2,000 ppm by weight of the cyclodextrin material.