Transparent closure cap liner having oxygen barrier properties

Abstract

Plastic compositions for liners in closures are disclosed. The compositions are blends of a synthetic butyl rubber component, a polyolefinic component and two or more lubricant type additives. The liners made from the composition are substantially transparent.

What is claimed:  
     
         1 . A substantially oxygen-impermeant closure cap liner composition comprising a blend of: 
 approximately 40-75%, by weight, of one or more butyl-based compounds;    approximately 25-60%, by weight, of a one or more polyolefinic compounds; and    approximately 1-17%, by weight, of two or more lubricant-type additives.    
     
     
         2 . The composition of  claim 1  wherein one or more said butyl-based compounds include polyisobutylene and butyl rubber.  
     
     
         3 . The composition of  claim 2  wherein the ratio of polyisobutylene to butyl rubber is between approximately 40:60 and 60:40.  
     
     
         4 . The composition of  claim 1  wherein one or more polyolefinic compounds include polymers selected from the group consisting of polypropylene, polyethylene, polybutylene and co-polymers thereof.  
     
     
         5 . The composition of  claim 4  wherein said one or more polyolefinic compounds include polyethylene and polypropylene.  
     
     
         6 . The composition of  claim 1  comprising a homopolymer of polypropylene and a co-polymer of polypropylene wherein the ratio of homopolymer to co-polymer is between approximately 40:60 and 60:40.  
     
     
         7 . The composition of  claim 1  wherein said lubricant-type additives are selected from the group consisting of silicone, fatty amide, microcrystalline wax and saturated monoglyceride.  
     
     
         8 . The composition of  claim 1  comprising: 
 approximately 20-60 parts, by weight, polyisobutylene;  
 approximately 20-60 parts, by weight, butyl rubber;  
 approximately 5-20 parts, by weight, polypropylene co-polymer;  
 approximately 5-20, parts, by weight, polypropylene homopolymer;  
 approximately 1-10 parts, by weight, microcrystalline wax;  
 approximately 1-10, parts by weight, fatty amide;  
 approximately 1-10 parts, by weight, silicone; and  
 approximately 1-10 parts, by weight, saturated monoglyceride.  
 
     
     
         9 . The composition of  claim 8  comprising: 
 approximately 35 parts, by weight, polyisobutylene;  
 approximately 40 parts, by weight, butyl rubber;  
 approximately 13 parts, by weight, polypropylene co-polymer;  
 approximately 12, parts, by weight, polypropylene homopolymer;  
 approximately 4 parts, by weight, microcrystalline wax;  
 approximately 5, parts by weight, fatty amide;  
 approximately 2.5-4 parts, by weight, silicone; and  
 approximately 4 parts, by weight, saturated monoglyceride.  
 
     
     
         10 . The composition of  claim 1  wherein said blend is substantially transparent.  
     
     
         11 . A closure comprising: 
 a plastic shell having and end panel and an integral skirt downwardly extending from the periphery thereof, said end panel having an inner surface;    substantially oxygen-impermeant liner adhered to said inner surface of said end panel wherein said liner comprises a blend of one or more butyl-rubber compounds, one or more polyolefinic compounds and two or more lubricant-type additives.    
     
     
         12 . The closure of  claim 11  wherein said liner is substantially transparent.  
     
     
         13 . The closure of  claim 12  wherein said end panel includes printing.  
     
     
         14 . The closure of  claim 11  wherein said liner comprises a blend of: 
 approximately 40-75%, by weight, of one or more butyl-based compounds;  
 approximately 25-60%, by weight, of a one or more polyolefinic compounds; and  
 approximately 1-17%, by weight, of two or more lubricant-type additives.  
 
     
     
         15 . The closure of  claim 13  wherein one or more said butyl-based compounds include polyisobutylene and butyl rubber.  
     
     
         16 . The closure of  claim 13  wherein one or more polyolefinic compounds include polymers selected from the group consisting of polypropylene, polyethylene, polybutylene and co-polymers thereof.  
     
     
         17 . The closure of  claim 13  wherein said lubricants are selected from the group consisting of silicone, fatty amide, microcrystalline wax and saturated monoglyceride.  
     
     
         18 . The closure of  claim 15  wherein the ratio of polyisobutylene to butyl rubber is between approximately 40:60 and 60:40.  
     
     
         19 . The closure of  claim 15  comprising a homopolymer of polypropylene and a co-polymer of polypropylene wherein the ratio of homopolymer to co-polymer is between approximately 40:60 and 60:40.  
     
     
         20 . The closure of  claim 11  comprising: 
 approximately 20-60 parts, by weight, polyisobutylene;  
 approximately 20-60 parts, by weight, butyl rubber;  
 approximately 5-20 parts, by weight, polypropylene co-polymer;  
 approximately 5-20, parts, by weight, polypropylene homopolymer;  
 approximately 1-10 parts, by weight, microcrystalline wax;  
 approximately 1-10, parts by weight, fatty amide;  
 approximately 1-10 parts, by weight, silicone; and  
 approximately 1-10 parts, by weight, saturated monoglyceride.