Leak-proof containers, made from expandable thermoplastic resin beads

Abstract

This invention discloses a leak proof disposable container, comprising of a bottom portion composed of expandable thermoplastic resin beads and a lidding film, for containing non-carbonated drinks or food products that do not require heating prior to consumption. The inventive container eliminates the use of polypropylene and polystyrene snap-on lids currently used for cups and containers. The snap-on lid is replaced with a thermoplastic lidding film, a leak proof seal is formed between the lidding film and upper flange of the bottom portion. Replacement of the snap-on lid with lidding film, reduces the weight of the disposable lidding material by 74 percent. Through the appropriate selection of materials, one can produce a leak proof container that is 100 percent recyclable under the #6 PS (polystyrene) symbol.

What is claimed is: 
     
         1 . A leak proof container for packaging food or drink comprising: a bottom portion having an upper flange circumferentially extending around at least one compartment for supporting a food or drink, wherein said bottom portion comprises expanded thermoplastic beads; and a lidding film attached to said upper flange, forming a leak proof seal, enclosing said food or drink. 
     
     
         2 . A leak proof container according to  claim 1 , wherein said bottom portion comprises expanded polystyrene beads. 
     
     
         3 . A leak proof container according to  claim 2 , wherein said bottom portion has a density from 0.5 pounds per cubic foot (8 g/L) to 12 pounds per cubic foot (192 g/L). 
     
     
         4 . A leak proof container according to  claim 3 , wherein said lidding film is a monolayer film. 
     
     
         5 . A leak proof container according to  claim 4 , wherein said monolayer lidding film comprises a styrene butadiene copolymer. 
     
     
         6 . A leak proof container according to  claim 5 , wherein an Average Plateau Peeling Force required to peel said monolayer lidding film from said leak proof container is greater than 0.32 pounds-force, or 1.4 Newton; wherein said Average Plateau Peeling Force is calculated from an Instron load-displacement curve (extension-mode) as said monolayer lidding film is peeled from 1 inch to 3 inches of travel on said upper flange. 
     
     
         7 . A leak proof container according to  claim 5 , wherein said monolayer lidding film attached to said leak proof container has an Average Puncture Force at Straw Breakthrough that is greater than 2.9 pounds-force, or 13 Newton; wherein said Average Puncture Force at Straw Breakthrough is calculated from an Instron load-displacement curve (compression-mode). 
     
     
         8 . A leak proof container according to  claim 4 , wherein said monolayer lidding film comprises an ethylene vinyl acetate copolymer containing from 3 wt % to 16 wt % vinyl acetate and a melt index from 0.2 dg/min to 20 dg/min; wherein melt index is determined by ASTM D-1238 at 190° C. and a 2.16 kg load. 
     
     
         9 . A leak proof container according to  claim 4 , wherein said monolayer lidding film comprises a polyolefin with a DSC melting point from 90° C. to 125° C. and a melt index from 0.2 dg/min to 20 dg/min; wherein melt index is determined by ASTM D-1238 at 190° C. and a 2.16 kg load. 
     
     
         10 . A leak proof container according to  claim 3 , wherein said lidding film is a multilayer film. 
     
     
         11 . A leak proof container according to  claim 10 , wherein said multilayer lidding film comprises an inner most layer comprising a styrene butadiene copolymer. 
     
     
         12 . A leak proof container according to  claim 11 , wherein an Average Plateau Peeling Force required to peel said multilayer lidding film from said leak proof container is greater than 0.32 pounds-force, or 1.4 Newton; wherein said Average Plateau Peeling Force is calculated from an Instron load-displacement curve (extension-mode) as said monolayer lidding film is peeled from 1 inch to 3 inches of travel on said upper flange. 
     
     
         13 . A leak proof container according to  claim 10 , wherein said multilayer lidding film comprises an inner most layer comprising an ethylene vinyl acetate copolymer containing 3 wt % to 16 wt % vinyl acetate and a melt index from 0.2 dg/min to 20 dg/min; wherein the melt index is determined by ASTM D-1238 at 190° C. and a 2.16 kg load. 
     
     
         14 . A leak proof container according to  claim 13 , wherein an Average Plateau Peeling Force required to peel said multilayer lidding film from said leak proof container is greater than 0.24 pounds-force, or 1.1 Newton; wherein said Average Plateau Peeling Force is calculated from an Instron load-displacement curve (extension-mode) as said multilayer lidding film is peeled from 1 inch to 3 inches of travel on said upper flange. 
     
     
         15 . A leak proof container according to  claim 10 , wherein the multilayer lidding film comprises an inner most layer comprising a polyolefin with a DSC melting point from 90° C. to 125° C. and a melt index from 0.2 dg/min to 20 dg/min; wherein the melt index is determined by ASTM D-1238 at 190° C. and a 2.16 kg load. 
     
     
         16 . A process for producing a leak proof container for food or drink comprising: (A) shape molding a bottom portion having an upper flange circumferentially extending around at least one compartment for supporting a food or drink, wherein said bottom portion comprises expanded thermoplastic beads; (B) transporting said bottom portion to a filling station; (C) filling said compartment(s) with said food or drink, forming a filled container; (D) transporting said filled container to a lidding station; (E) attaching a lidding film to said upper flange on said filled container, forming a leak proof container; (F) manually transporting said leak proof container to a point of purchase (single serving retail counter), or optionally mechanically transporting said leak proof container to a fully integrated bulk packaging line. 
     
     
         17 . A process according to  claim 16 , wherein said bottom portion comprises expanded polystyrene beads. 
     
     
         18 . A process according to  claim 17 , wherein said bottom portion has a density from 0.5 pounds per cubic foot (8 g/L) to 12 pounds per cubic foot (192 g/L). 
     
     
         19 . A process according to  claim 18 , wherein said lidding film is a monolayer film. 
     
     
         20 . A process according to  claim 19 , wherein said monolayer lidding film comprises a styrene butadiene copolymer. 
     
     
         21 . A process according to  claim 20 , wherein an Average Plateau Peeling Force required to peel said monolayer lidding film from said leak proof container is greater than 0.32 pounds-force, or 1.4 Newton; wherein said Average Plateau Peeling Force is calculated from an Instron load-displacement curve (extension-mode) as said monolayer lidding film is peeled from 1 inch to 3 inches of travel on said upper flange. 
     
     
         22 . A process according to  claim 20 , wherein said monolayer lidding film attached to said leak proof container has an Average Puncture Force at Straw Breakthrough that is greater than 2.9 pounds-force, or 13 Newton; wherein said Average Puncture Force at Straw Breakthrough is calculated from an Instron load-displacement curve (compression-mode). 
     
     
         23 . A process according to  claim 19 , wherein said monolayer lidding film comprises an ethylene vinyl acetate copolymer containing from 3 wt % to 16 wt % vinyl acetate and a melt index from 0.2 dg/min to 20 dg/min; wherein melt index is determined by ASTM D-1238 at 190° C. and a 2.16 kg load. 
     
     
         24 . A process according to  claim 19 , wherein said monolayer lidding film comprises a polyolefin with a DSC melting point from 90° C. to 125° C. and a melt index from 0.2 dg/min to 20 dg/min; wherein melt index is determined by ASTM D-1238 at 190° C. and a 2.16 kg load. 
     
     
         25 . A process according to  claim 18 , wherein said lidding film is a multilayer film. 
     
     
         26 . A process according to  claim 25 , wherein said multilayer lidding film comprises an inner most layer comprising styrene butadiene copolymer. 
     
     
         27 . A process according to  claim 26 , wherein an Average Plateau Peeling Force required to peel said multilayer lidding film from said leak proof container is greater than 0.32 pounds-force, or 1.4 Newton; wherein said Average Plateau Peeling Force is calculated from an Instron load-displacement curve (extension-mode) as said monolayer lidding film is peeled from 1 inch to 3 inches of travel on said upper flange. 
     
     
         28 . A process according to  claim 25 , wherein said multilayer lidding film comprises an inner most layer comprising an ethylene vinyl acetate copolymer containing 3 wt % to 16 wt % vinyl acetate and a melt index from 0.2 dg/min to 20 dg/min; wherein the melt index is determined by ASTM D-1238 at 190° C. and a 2.16 kg load. 
     
     
         29 . A process according to  claim 28 , wherein an Average Plateau Peeling Force required to peel said multilayer lidding film from said leak proof container is greater than 0.24 pounds-force, or 1.1 Newton; wherein said Average Plateau Peeling Force is calculated from an Instron load-displacement curve (extension-mode) as said multilayer lidding film is peeled from 1 inch to 3 inches of travel on said upper flange. 
     
     
         30 . A process according to  claim 25 , wherein the multilayer lidding film comprises an inner most layer comprising a polyolefin with a DSC melting point from 90° C. to 125° C. and a melt index from 0.2 dg/min to 20 dg/min; wherein the melt index is determined by ASTM D-1238 at 190° C. and a 2.16 kg load.