Thermoplastic film for a disposable container made of expandable thermoplastic particles

Abstract

A foam thermoplastic container e.g. cup, bowl molded from expandable thermoplastic particles e.g. expandable polystyrene, has a film made of a thermoplastic resin e.g. solid polystyrene, rubber-modified polystyrene, PET, polyethylene, polypropylene, fused to its inner sidewall surface by heat and pressure to create a barrier to resist the leakage of liquid and food with oil and/or fatty components and to increase the rim strength of the container. The thermoplastic resin film can be fused to the outer surface of the container for printing purposes and/or to create a barrier and/or can be fused to the base surfaces of the container. The molding machine used to form the foam container is used to fuse the film to the container.

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       13 . A method for forming a container for holding liquid and/or foods containing oil and/or fatty components, the steps comprising: 
 forming a foam thermoplastic container having a sidewall with an inner surface and an outer surface, and a base with an inner surface and an outer surface, and    fusing a thermoplastic film made of thermoplastic resin to at least one of said inner surface and said outer surface of said sidewall of said container to make said container resistant to the penetration of said liquid and/or said oil and/or fat components of said food through said sidewall of said container.    
   
   
       14 . A method of  claim 13  wherein said fusing comprises the application of heat at a temperature ranging from about 60° C. to about 120° C. for about 5 to about 20 seconds and the application of pressure to said thermoplastic film ranging from about 20 to about 80 pounds per square inch (psi).  
   
   
       15 . A method of  claim 13  wherein said foam thermoplastic container is fabricated via a container machine, the steps further comprising: 
 fusing said thermoplastic film to said one of said inner surface and said outer surface of said sidewall of said container said container machine.    
   
   
       16 . A method of  claim 13  the steps further comprising: 
 fusing a thermoplastic film made of thermoplastic resin to said inner surface of said sidewall of said container.    
   
   
       17 . A method of  claim 13  the steps further comprising: 
 fusing a thermoplastic film made of thermoplastic resin to said outer surface of said sidewall of said container.    
   
   
       18 . A method of  claim 13  the steps further comprising: 
 fusing a thermoplastic film made of thermoplastic resin to said base of said container.    
   
   
       19 . A method for preparing a thin walled container made from expandable polystyrene particles and which container is made to hold liquids and/or foods containing oil and/or fatty components, the steps comprising: 
 pre-expanding said expandable polystyrene particles to a density ranging from about 2.6 to about 3.6 pounds per cubic foot to form pre-expanded polystyrene particles,    in a molding process, using said pre-expanded polystyrene particles and further expanding said polystyrene particles to form said thin walled container comprising a sidewall with an inner surface, an outer surface and a rim, and said sidewall having voids formed between said polystyrene particles, and    after forming said thin walled container, encircling a thermoplastic film around said inner surface of said thin walled container and fusing said thermoplastic film to said inner surface to cover said voids in said sidewall and to further expand said polystyrene particles to make said container resistant to the penetration of said liquids and/or said oil and/or fat components of said foods through said sidewall of said thin walled container and to improve the strength of said rim of said thin walled container.    
   
   
       20 . A method of  claim 19  wherein said thermoplastic film is made of a polymer selected from the group consisting of solid polystyrene, rubber modified polystyrene, polymethyl methacrylate, polypropylene, polyethylene, polyethylene terephthalate (PET), and mixtures thereof.  
   
   
       21 . A method of  claim 20  wherein said thermoplastic film has a thickness ranging from about 0.10 mil to about 5.0 mils.  
   
   
       22 . A method of  claim 19  wherein said fusing comprises the application of heat at a temperature ranging from about 60° C. to about 120° C. for about 5 to about 20 seconds and the application of pressure to said thermoplastic film ranging from about 20 to about 80 pounds per square inch (psi).  
   
   
       23 . A method of  claim 19  wherein said foam thermoplastic container is fabricated via a container machine, the steps further comprising: 
 fusing said thermoplastic film to said one of said inner surface and said outer surface of said sidewall of said container by using said container machine.    
   
   
       24 . A method of  claim 19  the steps further comprising: 
 fusing a thermoplastic film made of thermoplastic resin to said outer surface of said sidewall of said container.    
   
   
       25 . A method of  claim 19  where said container further comprises a base, and the steps further comprising: 
 fusing a thermoplastic film made of thermoplastic resin to said base of said container.