Lightweight closure and container package

Abstract

A closure and container package for pressurized products, such as carbonated beverages, includes a closure comprising a closure cap having a top wall portion, and an annular skirt portion depending from the top wall portion. Features of the closure construction, and selection of the polymer from which the closure is formed, permits the closure to meet sealing, impact resistance, and other performance criteria, with desirably reduced use of polymeric material. Significant cost savings can thus be achieved.

What is claimed is: 
     
         1 . A lightweight closure, comprising:
 a closure cap having a top wall portion, and an annular skirt portion depending from said top wall portion,   said skirt portion including external knurl pattern, and an internal thread formation for threaded engagement with an external thread formation of an associated container; and   a tamper-evident band at least partially detachably connected to said skirt portion, said tamper-evident band being detachably connected to said skirt portion by a plurality of circumferentially spaced frangible bridges, each of said bridges being defined between scores that extend into said closure between said skirt portion and said tamper-evident band,   said closure being formed from high-density polyethylene polymer having a density of about 0.945 grams/cubic centimeter to about 0.97 grams/cubic centimeter, and having an Aggregate Lightweight Performance Index of at least about 40.   
     
     
         2 . A lightweight closure in accordance with  claim 1 , including:
 an outer seal element depending from said top wall portion inwardly of said annular skirt potion, said outer seal element being generally annular, and defining a generally inwardly facing sealing surface for engagement with a generally outwardly facing sealing surface of said container.   
     
     
         3 . A lightweight closure in accordance with  claim 2 , including:
 a plurality of circumferentially spaced, seal reinforcement elements on the inside surface of said skirt portion radially outwardly of said outer seal element and adjacent said top wall portion, said reinforcement elements being engageable by said outer seal element to limit outward deflection of said outer seal element, to enhance sealing cooperation of said outer seal element with the associated container.   
     
     
         4 . A lightweight closure for a container in accordance with  claim 1 , including:
 an inner plug seal element depending from said top wall portion, said plug seal element being generally cylindrical, and defining an outwardly facing sealing surface for sealing engagement with a generally inwardly facing, inside surface of an associated container.   
     
     
         5 . A lightweight closure for a container in accordance with  claim 1 , wherein:
 said polymer includes a colorant, and a nucleator.   
     
     
         6 . A lightweight closure for a container in accordance with  claim 1 , wherein:
 said closure weighs no more than approximately 1.95 grams.   
     
     
         7 . A lightweight closure for a container in accordance with  claim 1 , wherein:
 said polymer includes approximately 0.2 to 0.3% lubricant by weight.   
     
     
         8 . A lightweight closure for a container in accordance with  claim 1 , wherein:
 said tamper-evident band includes an annular band portion depending from said skirt portion that is detachably connected thereto, and an annular inner flange portion, extending inwardly from a lower margin of said annular band portion, said inner flange portion defining a plurality of circumferentially spaced openings spaced from a free edge thereof.   
     
     
         9 . A lightweight closure for a container in accordance with  claim 1 , wherein
 said internal thread formation is configured to provide a variation in retention force which decreases in a direction away from said top wall portion.   
     
     
         10 . A lightweight closure, comprising:
 a closure cap having a top wall portion, and an annular skirt portion depending from said top wall portion,   said skirt portion including external knurl pattern, and an internal thread formation for threaded engagement with an external thread formation of an associated container; and   a tamper-evident band at least partially detachably connected to said skirt portion, said tamper-evident band being detachably connected to said skirt portion by a plurality of circumferentially spaced frangible bridges, each of said bridges being defined between scores that extend into said closure between said skirt portion and said tamper-evident band,   said closure being formed from high-density polyethylene polymer having a density of about 0.945 grams/cubic centimeter to about 0.97 grams/cubic centimeter, and having a Sealing Index greater than about 1.3.   
     
     
         11 . A lightweight closure, comprising:
 a closure cap having a top wall portion, and an annular skirt portion depending from said top wall portion,   said skirt portion including external knurl pattern, and an internal thread formation for threaded engagement with an external thread formation of an associated container; and   a tamper-evident band at least partially detachably connected to said skirt portion, said tamper-evident band being detachably connected to said skirt portion by a plurality of circumferentially spaced frangible bridges, each of said bridges being defined between scores that extend into said closure between said skirt portion and said tamper-evident band,   said closure being formed from high-density polyethylene polymer having a density of about 0.945 grams/cubic centimeter to about 0.97 grams/cubic centimeter, and having a Strip Torque Value of greater than about 15.   
     
     
         12 . A lightweight closure, comprising:
 a closure cap having a top wall portion, and an annular skirt portion depending from said top wall portion,   said skirt portion including external knurl pattern, and an internal thread formation for threaded engagement with an external thread formation of an associated container,   said internal thread formation being configured to provide a variation in retention force which decreases in a direction away from said top wall portion;   an outer seal element depending from said top wall portion inwardly of said annular skirt potion, said outer seal element being generally annular, and defining a generally inwardly facing sealing surface for engagement with a generally outwardly facing sealing surface of said container, and   a tamper-evident band at least partially detachably connected to said skirt portion, said tamper-evident band being detachably connected to said skirt portion by a plurality of circumferentially spaced frangible bridges, each of said bridges being defined between circumferentially spaced scores that extend into said closure between said skirt portion and said tamper-evident band,   said closure being formed from high-density polyethylene polymer having a density of about 0.945 grams/cubic centimeter to about 0.97 grams/cubic centimeter, said polymer including a colorant, and a nucleator to minimize dimensional variations of the closure.   
     
     
         13 . A lightweight closure in accordance with  claim 12 , including
 a plurality of circumferentially spaced, seal reinforcement elements on the inside surface of said skirt portion radially outwardly of said outer seal element and adjacent said top wall portion, said reinforcement elements being engageable by said outer seal element to limit outward deflection of said outer seal element, to enhance sealing cooperation of said outer seal element with the associated container, and   
     
     
         14 . A lightweight closure in accordance with  claim 12 , including
 an outer seal element depending from said top wall portion inwardly of said annular skirt portion, said outer seal element being generally annular, and defining a generally inwardly facing sealing surface for engagement with a generally outwardly facing sealing surface of said container, and   an inner plug seal element depending from said top wall portion, said plug seal element being generally cylindrical, and defining an outwardly facing sealing surface for sealing engagement with a generally inwardly facing, inside surface of an associated container.   
     
     
         15 . A lightweight closure in accordance with  claim 12 , wherein
 said tamper-evident band includes an annular band portion depending from said skirt portion that is detachably connected thereto, and an annular inner flange portion, extending inwardly from a lower margin of said annular band portion,   said inner flange portion defining a plurality of circumferentially spaced openings spaced from a free edge thereof.   
     
     
         16 . A lightweight closure in accordance with  claim 12 , including
 an inner plug seal element depending from said top wall portion, said plug seal element being generally cylindrical, and defining an outwardly facing sealing surface for sealing engagement with a generally inwardly facing, inside surface of an associated container.   
     
     
         17 . A package, comprising:
 a container having carbonated contents; and   a lightweight closure, comprising a closure cap formed from a polymer and having a top wall portion, and an annular skirt portion depending from said top wall portion,   said skirt portion including external knurl pattern, and an internal thread formation for threaded engagement with an external thread formation of an associated container; and   a tamper-evident band at least partially detachably connected to said skirt portion, said tamper-evident band being detachably connected to said skirt portion by a plurality of circumferentially spaced frangible bridges, each of said bridges being defined between scores that extend into said closure between said skirt portion and said tamper-evident band,   an outer seal element depending from said top wall portion inwardly of said annular skirt potion, said outer seal element being generally annular, and defining a generally inwardly facing sealing surface for engagement with a generally outwardly facing sealing surface of said container, and   an inner plug seal element depending from said top wall portion, said plug seal element being generally cylindrical, and defining an outwardly facing sealing surface for sealing engagement with a generally inwardly facing, inside surface of an associated container,   wherein said closure has a weight of no more than about 1.95 grams, and an Aggregate Lightweight Performance Index of at least about 40.   
     
     
         18 . A package in accordance with  claim 17 , wherein
 said polymer includes approximately 0.2 to 0.3% lubricant by weight, a colorant, and a nucleator to minimize dimensional variations of the closure.   
     
     
         19 . A package in accordance with  claim 17 , wherein
 said closure being is formed from high-density polyethylene polymer having a density of about 0.945 grams/cubic centimeter to about 0.97 grams/cubic centimeter, said polymer including a colorant, and a nucleator to minimize dimensional variations of the closure.   
     
     
         20 . A package in accordance with  claim 17 , including
 a plurality of circumferentially spaced, seal reinforcement elements on the inside surface of said skirt portion radially outwardly of said outer seal element and adjacent said top wall portion, said reinforcement elements being engageable by said outer seal element to limit outward deflection of said outer seal element, to enhance sealing cooperation of said outer seal element with said container.