Disposable containers coated with a latex coating

Abstract

A molded thermoplastic container e.g. cup, bowl made from expandable thermoplastic particles e.g. expandable polystyrene, has a latex coating, e.g. latex of methyl methacrylate and styrene copolymer, latex of methyl acrylate and styrene copolymer, latex of acrylic acid and styrene copolymer, and latex of butadiene and styrene copolymer, applied to at least its inner surface via dipping, brushing or spraying processes for improved leakage and/or stain resistance and/or storage longevity. The coating may be applied to the outer surface of the container for leak resistance and printing purposes. A related method for forming the container, an article of manufacture, and an improved method for storing liquid and food substances are also disclosed.

1 . A molded thermoplastic container for retaining liquid and food substances and having inner and outer surfaces, comprising: 
 a latex coating applied to at least a portion of at least one of said inner and outer surfaces of said molded thermoplastic container for coating said container.    
     
     
         2 . The molded thermoplastic container of  claim 1  wherein said molded thermoplastic container is made from expandable thermoplastic particles.  
     
     
         3 . The molded thermoplastic container of  claim 2  wherein said expandable thermoplastic particles are expandable polystyrene particles.  
     
     
         4 . The molded thermoplastic container of  claim 1  wherein said latex coating is comprised of a monomer selected from the group consisting of butadiene, n-butyl acrylate, i-butyl acrylate, 2-ethylhexyl acrylate, methyl acrylate, ethyl acrylate, octyl acrylate, vinyl acetate, vinyl chloride, vinylidene chloride, vinyl pivalate, vinyl neo-decanoate, acrylonitrile, methyl acrylonitrile, acrylamide, styrene, α-methyl styrene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate.  
     
     
         5 . The molded thermoplastic container of  claim 4  wherein said latex coating is comprised of a polymer selected from the group consisting of a homopolymer, a copolymer of two or more of said monomers, and a copolymer of two or more of said monomers with the following functional monomers including acrylic acid, methacrylic acid, itaconic acid, fumaric acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, diethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, acrylamide, dimethyl meta-isopropenyl benzyl isocyanate, N-methylolacrylamide, N-methylol methacrylamide, N-(iso-butoxymethyl)acrylamide, glycidyl acrylate, glycidyl methacrylate, sodium styrene sulfonate.  
     
     
         6 . The molded thermoplastic container of  claim 1  wherein said latex coating is comprised of a polymer selected from the group consisting of acrylate, ethyl acrylate, methyl methacrylate, methacrylate, acrylic acid, methacrylic acid, and monomers or copolymers of said monomers combined with vinyl acetate or styrene.  
     
     
         7 . The molded thermoplastic container of  claim 1  wherein said latex coating is selected from the group consisting of latex of methyl methacrylate and styrene copolymer, latex of methyl acrylate and styrene copolymer, latex of acrylic acid and styrene copolymer, and latex of butadiene and styrene copolymer.  
     
     
         8 . The molded thermoplastic container of  claim 7  wherein said latex coating is latex of methyl acrylate and styrene copolymer.  
     
     
         9 . The molded thermoplastic container of  claim 1  wherein said latex coating has a thickness ranging from about 0.10 mils to about 5.0 mils.  
     
     
         10 . The molded thermoplastic container of  claim 1  wherein said latex coating is applied to said surfaces of said container via a spraying process, and wherein said latex coating when diluted has a solids content ranging from about 40% to about 47% by weight.  
     
     
         11 . The molded thermoplastic container of  claim 1  wherein said latex coating is applied to said surfaces of said container via a dipping process, and wherein said latex coating when diluted has a solids content ranging from about 8% to about 20% by weight.  
     
     
         12 . The molded thermoplastic container of  claim 1  wherein said latex coating is applied to said surfaces of said container via a brushing process, and wherein said latex coating when diluted has a solids content ranging from about 40% to about 47% by weight.  
     
     
         13 . The molded thermoplastic container of  claim 1  wherein said latex coating is comprised of a solids phase and a water phase, and wherein said solids phase is about 50% by weight based on the weight of the latex coating.  
     
     
         14 . A method for forming a container for retaining liquid and food substances, the steps comprising: 
 forming a molded thermoplastic container having an inner surface and an outer surface, and    applying a latex coating to at least a portion of at least one of said inner surface and said outer surface of said container for making said container leakage and/or stain resistant to said liquid and food substances.    
     
     
         15 . The method of  claim 14  the steps further comprising: 
 applying said latex coating to said inner surface of said container.    
     
     
         16 . The method of  claim 14  the steps further comprising: 
 applying said latex coating to said outer surface of said container.    
     
     
         17 . The method of  claim 14  wherein said latex coating is selected from the group consisting of latex of methyl methacrylate and styrene copolymer, latex of methyl acrylate and styrene copolymer, latex of acrylic acid and styrene copolymer, and latex of butadiene and styrene copolymer.  
     
     
         18 . The method of  claim 14  wherein said latex coating is latex of methyl acrylate and styrene copolymer.  
     
     
         19 . The method of  claim 14  wherein said latex coating is applied to said container via a spraying process.  
     
     
         20 . The method of  claim 14  wherein said latex coating is applied to said container via a dipping process.  
     
     
         21 . The method of  claim 14  wherein said latex coating is applied to said container via a brushing process.  
     
     
         22 . An article of manufacture having improved storage longevity, improved stain resistance, and/or improved leakage resistance, comprising: 
 a molded thermoplastic container coated with a latex coating and containing a liquid substance or a food substance.    
     
     
         23 . An article of manufacture of  claim 22  wherein said container has improved stain resistance.  
     
     
         24 . An improved method for storing liquid and food substances by using the container of  claim 1.