Paper laminate and method for producing the laminate and paperboard containers

A flattened tube blank for erection and sealing as a container, the tube blank being formed of the following laminate:

• a paperboard layer;
• a layer of a polyolefinic resin bonded to the outer surface of the paperboard layer;
• and
• a preformed layer of biaxially oriented polyethylene terephthalate film covering the inner surface of the paperboard layer, the film having one surface thereof bonded to the paperboard layer, its remaining surface having the property of being heat sealable to itself and being exposed inwardly within the tube blank;
• the tube blank having a side seam formed by overlapping surfaces of the polyethylene terephthalate film and polyolefinic resin activated and bonded to one another by flame heat sealing without interposition of an adhesive.

A process for improving the resistance of a paper substrate to the migration or absorption of volatiles from a packaged material, comprising the following steps:

• bonding a first surface of the paper substrate to one surface of a preformed layer of biaxially oriented polyethylene terephthalate film, the remaining film surface having the property of being heat sealable to itself;
• coating the remaining surface of the paper substrate with a polyolefinic resin;
• and
• manufacturing a container by exposing the coated outer surface of the paper substrate and the remaining surface of the film to a flame to activate and bond the surfaces during utilization of flame heat sealing techniques without interposition of an adhesive.