Container

Abstract

A package is provided with a lid and container that are heat sealed together. A multi-ply sheet material is provided for being thermoformed to define the container which has a tapering wall and bulge-resistant bottom end. Prior to thermoforming the container from the sheet, the sheet is heated with oval pads on a plurality of plates which are arranged in a configuration to facilitate control of the sheet temperature. A plug is used in the thermoforming process to contact the sheet and position the sheet within a die. A lid sheet is heat sealed to the container sheet over the thermoformed containers so as to produce a pair of spaced-apart, annular bead heat seals. The package is completed by severing the sealed-together sheets at the periphery of the container with a punch and die set that produces and clean, smooth cut surface.

What is claimed is:  
     
         1 . A sealed package comprising; 
 a container having a body defining a mouth and having a flange around said mouth; and    a lid disposed on said container across said mouth and flange, said flange having an annular, upset first bead of a heat-sealable thermoplastic material, said lid having an annular second bead of a heat-sealable thermoplastic material adjacent said first bead, said first and second beads being sealed together with a first heat seal comprising a resolidification of a melted interface portion of said first and second beads.    
     
     
         2 . A sealed package in accordance with    claim 1   , wherein: 
 said flange has an annular, upset third board of a heat-sealable thermoplastic material;    said lid has an annular fourth bead of a heat sealable thermoplastic material adjacent said third bead; and    said package includes a second heat seal comprising a resolidification of a melted interface portion of said third and fourth beads.    
     
     
         3 . A sealed package in accordance with    claim 2   , wherein said first and third beads are spaced apart and are located between said second and fourth beads.  
     
     
         4 . A sealed package in accordance with    claim 2   , wherein said lid is sealed to said flange outwardly of said lid fourth bead in a substantially annular configuration extending from said fourth bead to an outer edge of said flange.  
     
     
         5 . A sealed package in accordance with    claim 2   , wherein said flange is deformed between said first and third beads to define a recess receiving a downwardly projecting portion of said lid.  
     
     
         6 . A sealed package in accordance with    claim 2   , wherein said lid defining an upwardly projecting portion above said second bead and an upwardly projecting portion above said fourth bead.  
     
     
         7 . A sealed package in accordance with    claim 6   , wherein said lid is deformed between said upwardly projecting portions of said lid to define an annular recess on an exterior of said lid.  
     
     
         8 . A sealed package in accordance with    claim 2   , wherein said lid comprises a heat sealable material, and wherein said second and third beads are formed from a lateral displacement of said heat sealable material.  
     
     
         9 . A container formed from a sheet material, said container comprising a unitary structure of said sheet material, said container further comprising: 
 peripheral flange defining an opening;    a downwardly and inwardly tapering hollow body defined around a longitudinal axis by a generally annular sidewall extending downwardly from said flange;    a bottom wall comprising: (1) an annular, curved, peripheral base extending from a lower end of said body sidewall, said base constructed to engage a flat support surface along a generally circular line of contact; (2) an annular first end wall extending from said annular curved, peripheral base both inwardly and toward said opening defined by said flange; (3) an annular second end wall located closer to said opening than said first end wall and extending from said first end wall both inwardly and toward said opening defined by said flange; and (4) a central, third end wall located closer to said opening defined by said flange than said second end wall and extending from said second end wall.    
     
     
         10 . A container in accordance with    claim 9   , wherein said first end wall defines a substantially frustoconical exterior surface.  
     
     
         11 . A container in accordance with    claim 9   , wherein a thickness of said sidewall increases with increasing distance from said flange toward said base.  
     
     
         12 . A container in accordance with    claim 9   , wherein said sidewall tapers at an angle of between about 1.8 degrees and about 3.2 degrees relative to said longitudinal axis.  
     
     
         13 . A container in accordance with    claim 9   , wherein said sheet material comprises: 
 a plurality of layers of material co-extruded together to form a multi-ply sheet comprising first, second, third, fourth, and fifth layers, said sheet first layer adapted for functioning as an exterior side of the container and comprising polypropylene, said second layer functioning as an adhesive joining said first and third layers, said third layer functioning as an oxygen barrier and comprising ethylene vinyl alcohol, said fourth layer functioning as an adhesive joining said third and fifth layers, and said fifth layer adapted for functioning as an interior side of the container and comprising polypropylene.    
     
     
         14 . A container in accordance with    claim 9   , wherein said second end wall defines an angle of about 45 degrees relative to said longitudinal axis.  
     
     
         15 . A container formed from a sheet material, said container comprising a unitary structure of said sheet material, said container further comprising: 
 a peripheral flange defining an opening;    a downwardly and inwardly tapering hollow body defined around a longitudinal axis by a generally frustoconical annular sidewall extending downwardly from said flange;    a bottom which includes an annular, curved, peripheral base extending from a lower end of said body sidewall, said sidewall increasing in thickness with increasing distance from said opening.    
     
     
         16 . A container in accordance with    claim 15   , wherein said sidewall defines a generally frustoconical exterior surface defining an angle between about 1.8 degrees and about 3.2 degrees relative to said longitudinal axis.  
     
     
         17 . A container in accordance with    claim 15   , wherein said sheet material comprises: 
 a plurality of layers of material co-extruded together to form a multi-ply sheet comprising first, second, third, fourth, and fifth layers, said sheet first layer adapted for functioning as an exterior side of the container and comprising polypropylene, said second layer functioning as an adhesive joining said first and third layers, said third layer functioning as an oxygen barrier and comprising ethylene vinyl alcohol, said fourth layer functioning as an adhesive joining said third and fifth layers, and said fifth layer adapted for functioning as an interior side of the container and comprising polypropylene.    
     
     
         18 . A container formed from a thermoplastic sheet material, said container comprising a unitary structure of said sheet material, said container further comprising: 
 a peripheral flange defining an opening;    a downwardly and inwardly tapering hollow body defined around a longitudinal axis by a sidewall extending downwardly from said flange; and    a bottom defined by (1) an annular, peripheral base extending from a lower end of said body sidewall, and (2) an end wall structure that extends radially inwardly from said peripheral base and that is located closer to said opening than is said peripheral base.    
     
     
         19 . A container in accordance with    claim 18   , wherein said first end wall defines a substantially frustoconical exterior surface.  
     
     
         20 . A container in accordance with    claim 18   , wherein said sidewall defines a generally frustoconical exterior surface defining an angle between about 1.8 degrees and about 3.2 degrees relative to said longitudinal axis.