Packaging laminates based on cardboard and paper

Abstract

A folded moisture and heat resistant container is manufactured of a material of laminate type in the form of a sheet or a web, said laminate comprising at least a base layer ( 1 ), an outer coating ( 2 ) and an inner coating ( 3 ). The material is at least on one side thereof heat treated in an autoclave. In the material the case layer ( 1 ) consists of a liquid absorbing material, the outer coating ( 2 ) consists of a polymer selected from the group including polypropylene, oriented polypropylene, metalized high density polyethylene, linear low density polyethylene, unmodified polyester, metalized polyester and amorphous polyester, and the inner coating ( 3 ) consists of a polymer selected from the group including polypropylene, high density polyethylene, linear low density polyethylene, unmodified amorphous polyester

What is claimed is:  
     
         1 . A folded moisture and heat resistant container manufactured from a laminate in the form of a sheet or a web, said laminate comprising at least one base layer, an outer coating and an inner coating, said laminate on at least one side thereof being heat treated in an autoclave, characterized in that the base layer consists of a liquid absorbing material, the outer coating consists of a polymer selected from the group consisting of polypropylene, oriented polypropylene, metalized oriented polypropylene, high density polyethylene, metalized high density polyethylene, linear low density polyethylene, unmodified polyester, metalized polyester and amorphous polyester, and the inner coating consists of a polymer selected from the group consisting of polypropylene, high density polyethylene, linear low density polyethylene, unmodified polyester and amorphous polyester.  
     
     
         2 . A container as claimed in  claim 1 , wherein said base layer consists of paper or cardboard.  
     
     
         3 . A container as claimed in  claim 1 , wherein said laminate additionally includes a barrier layer between the base layer and the inner coating, said barrier layer comprising a material selected from the group consisting of aluminum, an aluminum oxide coating, a silica coating, ethylene/vinyl alcohol, polyvinyl alcohol, metalized oriented polyester and metalized oriented polypropylene.  
     
     
         4 . A container as claimed in  claim 1 , wherein said laminate additionally includes a layer between the base layer and the outer coating, said layer being selected from the group consisting of polypropylene, low density polyethylene, medium density polyethylene, high density polyethylene and amorphous polyester.  
     
     
         5 . A container as claimed in  claim 3 , wherein said laminate additionally includes a coating adjacent one or both sides of the barrier layer, said coating being selected from the group consisting of an adhesion plastic, a heated sealable plastic, a primer and a lacquer.  
     
     
         6 . A container as claimed in  claim 1  wherein said laminate is capable of withstanding heat treatment in an autoclave at a temperature of approximately 105-122° C. and at a pressure at above or greater than atmosphere.