Closure with gasket

Abstract

A metal closure having multiple thread engaging lugs configured to decrease the pressure exerted by the closure lugs on the neck of a container is provided. In various embodiments, the metal closure comprises a top wall, a skirt extending downward from a peripheral edge of the top wall, a lower edge included on the skirt, and a plurality of lugs formed at the lower edge of the skirt. Pressure may be decreased by the closure having more lugs and/or larger lugs than other metal closures. The closure is provided with a gasket configured to provide enhanced sealing properties when the closure is secured to a container.

We claim: 
     
         1 . A closure configured for used with a plastic container, the closure comprising:
 a circular top panel;   a skirt extending downwardly from an outer periphery of the top panel;   at least five metallic lugs spaced about and extending radially inwardly from a lower portion of the skirt, wherein the lugs are configured to engage plastic threads formed on a neck of the container;   wherein each of the lugs comprises a front end and a rear end, the front end of each lug extending further radially inwards than the rear end of each lug, the lugs extending along a non-zero angle between the front end and the rear end;   the closure having a diameter of at least 58 mm, and each lug having a length as defined in a circumferential direction of between 0.5 inches and 1.5 inches;   a gasket attached to and extending about at least a portion of a lower surface of the top panel;   wherein the gasket has a permanent deformation of between approximately 30% and 70% as measured under conditions in which a specimen of the gasket is compressed by approximately 25% for a period of twenty-two (22) hours at a temperature of 158° F., and is subsequently allowed to cool for 30 minutes.   
     
     
         2 . The closure of  claim 1 , wherein the gasket is formed from a polymer material comprising a minimum content of 5% by weight of styrene-based block copolymer and a minimum content of 10% by weight of a propylene polymer and/or propylene copolymer. 
     
     
         3 . A closure according to  claim 1 , wherein the gasket is formed from a polymer material having barrier properties to oxygen and volatile compounds, at least one oxygen depleting compound, and comprises no more than 5% by weight of an oil or any other component that is liquid at room temperature. 
     
     
         4 . The closure of  claim 3 , wherein the polymer material is a non-cross linked barrier polymer. 
     
     
         5 . The closure of  claim 4 , wherein the non-cross linked barrier polymer material is selected from the group consisting of butyl rubber, polyisoprene, polyisobutylene, styrene isoprene butadiene (SIBS), polybutene, and polyolefin;
 the non-cross linked barrier polymer being present in an amount of between 10% to 50% by weight of the polymer-containing composition.   
     
     
         6 . The closure of  claim 3 , wherein the polymer comprises a polyolefin selected from the group consisting of high-density polyethylene (HDPE), polypropylene (PP) or a copolymer of polypropylene and ethylene (co-PP). 
     
     
         7 . The closure of  claim 5 , wherein the polymer material has a Shore D hardness from 20 to 60 and a melt flow index (190° C., 5 kg) from 5 to 25. 
     
     
         8 . A closure configured for used with a plastic container, the closure comprising:
 a circular top panel;   a skirt extending downwardly from an outer periphery of the top panel;   five or more lugs spaced about and extending radially inwardly from a lower portion of the skirt, wherein the lugs are configured to engage threads formed on a neck of the container;   the closure having a diameter of at least 58 mm;   each lug occupying between 5 percent and 15 percent of a perimeter defined by the lower portion of the skirt;   wherein a midpoint of each lug is spaced no more than approximately 72 degrees form a midpoint of an adjacent lug, as measured from a center of the closure;   a gasket attached to and extending about at least a portion of a lower surface of the top panel, the gasket formed of a material comprising at least one polymer;
 wherein the gasket is configured such that, following a hot filling process of up to 100° C. for up to 60 minutes the gasket retains the ability to provide a hermetic seal for contents of a container to which the closure is attached; 
 the gasket further being configured such that following the hot-fill process, the migration of the components of the material forming the gasket into the contents of the container is no more than 1,000 parts-per-billion. 
   
     
     
         9 . The closure of  claim 8 , wherein the gasket is formed from a polymer material comprising a copolymer which comprises polyethylene and octene. 
     
     
         10 . The closure of  claim 9 , wherein the polymer material further comprises a of a random copolymer composed of a linear or branched interpolymer of ethylene and at least one C 3 -C 20  alpha-olefin. 
     
     
         11 . The closure of  claim 8 , wherein the gasket is formed from a polymer comprising a thermoplastic elastomer, at least one polyolefin component and white oil in an amount of not more than 50%. 
     
     
         12 . The closure of  claim 11 , wherein the thermoplastic elastomer is based on styrene-ethylene-butylene-styrene and is present at 20% to 30% of the weight of the polymer. 
     
     
         13 . The closure of  claim 12 , wherein the polyolefin is selected from the group consisting of: between 10% to 30% linear low-density polyethylene (LLDPE); between 5% to 25% low density polyethylene (LDPE); between 2% to 20% copolymer consisting of polypropylene and polyethylene; at least 20% of a block copolymer that is an interpolymer of ethylene and at least one C 3 -C 20  alpha-olefin and at least 20% a copolymer of ethylene and one C 3 -C 20  alpha-olefin. 
     
     
         14 . The closure of  claim 13 , wherein the polymer comprises between 20% to 45% white oil. 
     
     
         15 . The closure of  claim 13 , the polymer further comprising one oxygen-scavenging substance. 
     
     
         16 . The closure of  claim 15 , wherein the Shore A hardness of the polymer is between 60 to 80 and the polymer exhibits a permanent deformation between 30% and 90% determined after 25% compression at 70° C., and 22 h. 
     
     
         17 . The closure of  claim 15  wherein the oxygen-scavenging substance comprises sodium sulfite with an average particle size smaller than 20 microns. 
     
     
         18 . A method of forming a closure comprising:
 providing a closure having:
 a circular top panel having an upper surface and a lower surface; 
 a channel formed in and extending circumferentially about a portion of the lower surface of the top panel configured to overlie a mouth of a container to which the closure is configured to be applied; 
 a skirt extending downwardly from an outer periphery of the top panel; 
 a plurality of lugs spaced about a lower portion of the skirt, the lugs extending radially inwardly towards a center of the closure such that at least a portion of each lug extends over and blocks access to at least a portion of the lower surface of the top panel; 
 wherein the number of lugs is at least five; 
 wherein the closure has a diameter of at least 58 mm; and 
   extruding a gasket-forming material onto the lower surface of the top panel, the gasket-forming material being sufficiently flowable such that at least a portion of the extruded material flows into and fills the channel to form a gasket that is configured to engage and seal the mouth of the container;   the gasket-forming material being extruded onto the top panel subsequent to the lugs being formed;
 wherein the gasket-forming material has a permanent deformation of between approximately 30% and 70% as measured under conditions in which a specimen of the gasket is compressed by approximately 25% for a period of twenty-two (22) hours at a temperature of 158° F., and is subsequently allowed to cool for 30 minutes. 
   
     
     
         19 . The method of  claim 18 , wherein the gasket-forming material is shaped by stamping. 
     
     
         20 . The method of  claim 18 , wherein the gasket-forming material has a Shore A hardness of between 40 to 90.