Lidded paperboard container

Abstract

This invention relates generally to lidded disposable pressed paperboard containers and more particularly to a disposable lid with an engagement profile particularly useful for paperboard containers comprising evert outer portions. The lid of the present invention provides a good fit for paperboard container bases having evert outer portions while still allowing the lid to be removed from the base without the need for excessive force. The lid profile is relatively insensitive to size variations of paperboard container bases having evert outer portions and allows for flexing of paperboard during application so as to provide an unexpectedly good seal so as to provide lidded, disposable paperboard containers.

1 ) A disposable container comprising: 
 a) a domed lid having: 
 i) a central lid portion;  
 ii) a fluted sidewall extending downwardly from the central lid portion, the fluted sidewall of the domed lid being provided with a plurality of flutes, such that the fluted sidewall defines a fluted base at its lower portion; and  
 iii) a rim extending outwardly and downwardly from the fluted sidewall providing an annular engagement portion defining a lid engagement circumference, the rim being further provided with a plurality of generally equally spaced undercut lugs around the annular engagement portion of the domed lid; and  
 iv) a pressed paperboard container having an evert outer portion;  
   wherein the plurality of undercut lugs of the lid rim are sized to secure the lid to the container and have a collective undercut span of from about 15% to about 30% of the lid engagement circumference, and wherein the perimeter of the base and the annular engagement portion of the lid rim are sized to engage each other when the lid is installed on the base.    
     
     
         2 ) The container of  claim 1 , wherein the plurality of undercut lugs of the lid rim define an undercut span of from about 20% to about 25% of the lid engagement circumference.  
     
     
         3 ) The container of  claim 1 , wherein the lid rim is provided with from about 7 to about 15 generally equally spaced undercut lugs around the annular engagement portion thereof.  
     
     
         4 ) The container of  claim 1 , wherein the lid rim is provided with from about 10 to about 12 generally equally spaced undercut lugs around the annular engagement portion thereof.  
     
     
         5 ) The container of  claim 1 , wherein the undercut lugs of the lid rim have an undercut depth of from about 25 mils to about 100 mils.  
     
     
         6 ) The container of  claim 1 , wherein the undercut lugs of the lid rim have an undercut circumferential span of from about ¼″ to about 1″.  
     
     
         7 ) The container of  claim 1 , wherein the lid rim has an outwardly extending wall adjacent the fluted base of the sidewall and a downwardly extending engagement wall defining the annular engagement portion of the rim above the undercut lugs, wherein the outwardly extending wall defines a headspace of at least about 30 mils above the brim of the container base when the lid is installed on the base.  
     
     
         8 ) The container to  claim 1 , wherein the lid rim has an outwardly extending wall adjacent the fluted base of the sidewall and a downwardly extending engagement wall defining the annular engagement portion of the rim above the undercut lugs, wherein the outwardly extending wall defines a headspace of from about 30 mils to about 150 mils when the lid is installed on the base.  
     
     
         9 ) The container of  claim 1 , wherein the sidewall of the lid is provided with a plurality of outwardly convex flutes.  
     
     
         10 ) The container of  claim 9 , wherein the flutes have a radius of curvature of from about 0.125″ to about 1″.  
     
     
         11 ) The container of  claim 9 , wherein there is from about 1.5 to about 1.9 outwardly convex flutes per inch of engagement circumference of the lid.  
     
     
         12 ) The container of  claim 1 , wherein the domed lid is provided with from about 35 to about 75 generally uniform outwardly convex flutes.  
     
     
         13 ) The container of  claim 1 , wherein the domed lid and container base are configured and dimensioned such that the perimeter of the container base is vertically aligned with the fluted base of the sidewall within an offset distance of about ¼ to about ⅜″ when the domed lid is installed on the base.