Container assemblies including metal closures and thermoplastic containers and methods of hot-filling food and beverage products

Abstract

Container assemblies are described herein that include a metal closure and a container including a plastic finish. The container assemblies may be characterized by improved performance including reproducibility of force needed to remove the closure. Furthermore, the container assemblies described herein may be compatible for use with hot-fill packaging processes.

1 . A container assembly comprising:
 a plastic container including an opening and a finish, said finish including a plastic material that is softer than glass;   wherein said finish includes one or more threads; and   a one-piece metal closure including a top panel, a sidewall extending downward from said top panel, and four lugs extending inward from said sidewall;   wherein said lugs are configured to engage said one or more threads when said metal closure is placed and rotated on said plastic container to pull said plastic container and said metal closure together in order to provide an engaged configuration;   wherein each of said lugs includes at least one of a top portion with a radius of curvature of greater than about 2.5 mm and an inner portion with a radius of curvature of greater than about 1.5 mm;   wherein a shape of said lugs is configured to minimize a sample-to-sample variation of a force needed to open said container assembly when said container assembly is in said engaged configuration.   
     
     
         2 . The container assembly of  claim 1  wherein said top portion has a radius of curvature of between about 2.5 mm and about 3.5 mm. 
     
     
         3 . The container assembly of  claim 1  wherein said inner portion has a radius of curvature of between about 1.5 mm and about 2.5 mm. 
     
     
         4 . The container assembly of  claim 1  wherein said plastic material is a thermoplastic material. 
     
     
         5 . The container assembly of  claim 1  wherein said plastic material is polyethylene terephthalate. 
     
     
         6 . The container assembly of  claim 1  wherein said lugs are evenly spaced about said metal closure. 
     
     
         7 . The container assembly of  claim 1  wherein said metal closure comprises an inner diameter of about 38 mm. 
     
     
         8 . The container assembly of  claim 1  wherein said finish comprises an inner diameter of about 28 mm to about 32 mm. 
     
     
         9 . The container assembly of  claim 1  wherein said finish comprises an outer diameter of about 33 mm to about 37 mm. 
     
     
         10 . The container assembly of  claim 1  wherein said closure sidewall comprises a cylindrical sidewall. 
     
     
         11 . The container assembly of  claim 1  wherein said metal closure comprises a gasketing material configured for sealing engagement with a top edge of said finish. 
     
     
         12 . A beverage product comprising:
 a beverage sterilized using a hot-fill packaging process; and   a container assembly in which said beverage is disposed and including a one-piece metal closure engaged on a container that includes a thermoplastic finish having one or more threads in order to provide sealing engagement between said container and said one-piece metal closure;   wherein said container includes an opening of about 28 mm to about 32 mm;   wherein said one-piece metal closure includes a top panel including a curved profile providing an enhanced level of flexibility over a corresponding flat top panel and an annular edge portion, a cylindrical sidewall depending from said edge portion, and four lugs depending inward from said sidewall;   wherein each of said lugs includes a curled edge, the curled edge including at least one of a top portion with a radius of curvature of greater than about 2.5 mm and an inner portion with a radius of curvature of greater than about 1.5 mm;   wherein said lugs are configured to engage said one or more threads in order to provide said sealing engagement between said container and said metal closure, a shape of said lugs being configured to minimize disruption of said sealing engagement due to thermoplastic deformation of said thermoplastic finish during said hot-fill packaging process.   
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . The product of  claim 12   wherein said top portion has a radius of curvature of between about 2.5 mm and about 3.5 mm.   
     
     
         16 . The product of  claim 12   wherein said inner portion has a radius of curvature of between about 1.5 mm and about 2.5 mm.   
     
     
         17 . A method of packaging a food or beverage product comprising:
 treating a food or beverage product to a condition that includes application of an elevated temperature greater than about 50° C.;   partially cooling the food or beverage product;   adding the food or beverage product to a container comprising a thermoplastic finish having at least one thread;   capping the food or beverage product in said container by rotating a one-piece metal closure onto said finish, said one-piece metal closure comprising four lugs engaged with said at least one thread sufficient to provide an air-vacuum tight seal;   wherein the one-piece metal closure includes a curved top panel, the curved top panel providing an increased degree of flexibility as compared to a flat top panel;   wherein each of said lugs includes a curled edge, the curled edge including at least one of a top portion with a radius of curvature of greater than about 2.5 mm and an inner portion with a radius of curvature of greater than about 1.5 mm;   maintaining the food or beverage product and the container at a hold temperature less than said elevated temperature; and   further cooling the food or beverage product and the container.   
     
     
         18 . The method of  claim 17  wherein said elevated temperature is no greater than about 100° C. and wherein said hold temperature is between about 65° C. to about 90° C. 
     
     
         19 . The method of  claim 17  wherein said curved top panel is a vacuum-indicating top panel. 
     
     
         20 . The method of  claim 17  wherein said capping further comprises engaging said lugs with a sidewall of said finish. 
     
     
         21 . The container assembly of  claim 1  wherein said top panel includes a curved profile providing an enhanced level of flexibility over a similar flat top panel. 
     
     
         22 . The container assembly of  claim 1  wherein said lugs include a lug width from about 3.0 mm to about 3.5 mm.