Package lid, method for manufacturing the same and package sealed with the lid

Abstract

The invention relates to a lid ( 1 ) that can be heat-sealed to the opening of a package ( 2 ) and peeled off as the package is opened. In addition, the invention comprises methods for manufacturing such a lid and a package sealed with the lid, and also a sealed package equipped with a lid. The lid ( 1 ) consists of a fibrous material layer ( 6 ), whichmay be paper or cardboard, a polymer oxygen-barrier layer ( 7 ), suitable materials of which are polyethylene terephthalate (PET), ethylene vinyl alcohol copolymer (EVOH) or polyamide (PA), and a polymer heat-seal layer ( 8 ). In accordance with the invention, the heat-seal layer ( 8 ) combines ethylene methyl acrylate copolymer (EMA), ethylene vinyl acetate copolymer (EVA) and polyamide wax, adherence of the heat-seal layer directly to the oxygen-barrier layer ( 7 ) having been allowed without any intermediate binder. During the manufacture of the lid, the oxygen-barrier and heat-seal layers ( 7, 8 ) can be applied onto paper or cardboard by coextrusion. The packages equipped with a lid in accordance with the invention comprises boxes, cups or goblets, for instance, into which foodstuffs, such as drinks, nutrients fats or ready-made foods have been packaged.

1 . A lid that can be heated-sealed to an opening of a package and peeled off as the package is opened, the lid comprising: 
 a fibrous material layer,    a polymer oxygen-barrier layer, and    a polymer heat-seal layer comprising ethylene methyl acrylate copolymer, ethylene vinyl acetate copolymer and polyamide wax,    wherein the oxygen-barrier layer having a higher melting point than the polymer heat seal layer and wherein the heat-seal layer is adhered directly to the oxygen-barrier layer without any intermediate binder.    
     
     
         2 . A lid as defined in  claim 1 , wherein the polymer coating on the fibrous material consists merely of said oxygen-barrier and the heat-seal layer.  
     
     
         3 . A lid as defined in  claim 1 , wherein the polymer in the oxygen-barrier layer is comprised of at least one of polyethylene terephthalate, ethylene vinyl alcohol co-polymer and/or polyamide.  
     
     
         4 . A lid as defined in  claim 3 , wherein the PET or PA oxygen-barrier layer has a weight in the range from 10 to 70 g/m 2 , preferably from 20 to 40 g/m 2 .  
     
     
         5 . A lid as defined in  claim 3 , wherein the EVOH oxygen-barrier layer has a weight in the range from 5 to 25 g/m 2 , preferably from 10 to 20 g/m 2 .  
     
     
         6 . A lid as defined in  claim 1 , wherein the heat-seal layer has a weight in the range from 5 to 30 g/m 2 , preferably from 10 to 20 g/m 2 .  
     
     
         7 . A lid as defined in  claim 1 , wherein the fibrous material layer is made up of paper having a weight in the range from 30 to 120 g/m 2 , preferably from 40 to 80 g/m 2 .  
     
     
         8 . A lid as defined in  claim 1 , wherein the fibrous material layer is made up of cardboard having a weight in the range from 130 to 600 g/m 2 , preferably from 220 to 300 g/m 2 .  
     
     
         9 . A method from manufacturing a lid fixable by heat sealing to an opening of a package that may be peeled off as the package is opened, the method comprising the steps of: 
 coating fibrous material by co-extrusion in one single step with two polymer layers adhering to fibers of the fibrous material and to one another, one of said layers forming the oxygen-barrier layer and the other forming a heat-seal layer comprising at least one of a blend of ethylene methyl acrylate copolymer ethylene vinyl acetate copolymer and polyamide wax.    
     
     
         10 . A method as defined in  claim 9 , further comprising the steps of: 
 providing the fibrous material as a moving fibrous material web,    extruding the polymer layers as continuous films on said moving fibrous material web; and    separating discrete from the web by one of cutting and punching.    
     
     
         11 . A method for manufacturing a sealed package, with a lid that allows the lid to be peeled off as the package is opened, the method comprising the steps of: 
 forming the lid from a fibrous material layer, a polymer oxygen-barrier layer and a heat-seal layer, the heat-seal layer adhered directly to the oxygen-barrier layer without intermediate binder, the heat-seal layer containing a blend of ethylene methyl acrylate copolymer, ethylene vinyl acetate copolymer and polyamide wax, and    heat-sealing the lid at the opening of the package.    
     
     
         12 . A method as defined in  claim 11 , further comprising the step of having the heat-sealing temperature is in the range from 150 to 190° C.  
     
     
         13 . A sealed package manufactured with the method of  claim 11  wherein the package comprises a container, a packaged product contained in the container and a lid heat-sealed at the opening of the container, the lid being made up of a fibrous material layer, a subjacent polymer oxygen-barrier layer, and a heat-seal layer forming the inner surface of the lid and adhered directly to the oxygen-barrier layer without any intermediate binder, the heat-seal layer containing ethylene methyl acrylate copolymer, ethylene vinyl acetate copolymer and polyamide wax, and allowing the lid to be peeled off as the package is opened.  
     
     
         14 . A package as defined in  claim 13 , wherein the container is a cardboard box, cup or goblet coated with polymer on the inside and/or the outside.  
     
     
         15 . A package as defined in  claim 13 , wherein the container is a plastic box, cup or goblet.  
     
     
         16 . A package as defined in  claim 13 , wherein the container is made of glass.  
     
     
         17 . A package as defined in  claim 13 , wherein the package is a sealed food package.  
     
     
         18 . A package having a lid heated-sealed to an opening of the package and peelable off as the package is opened, the lid comprising: 
 a fibrous material layer,    a polymer oxygen-barrier layer, and    a polymer heat-seal layer comprising at least one of ethylene methyl acrylate copolymer, ethylene vinyl acetate copolymer and polyamide wax,    wherein the oxygen-barrier layer has a higher melting point than the polymer heat seal layer and wherein the heat-seal layer is adhered directly to the oxygen-barrier layer without any intermediate binder.