Unsupported lap-sealable liner for composite container

Abstract

An unsupported lap-sealable liner for a composite container comprises a heat seal layer, a barrier web having a first surface attached to the heat seal layer and having an opposite second surface, and a sealable primer applied as an aqueous dispersion to the second surface of the barrier web and then dried. The sealable primer comprises a polymer having bonding affinity with wet adhesive used for bonding the liner to a paperboard surface of a composite container. The sealable primer furthermore is heat-sealable to the heat seal layer such that the liner is lap-sealable.

1 . A composite container, comprising: 
 a tubular body wall comprising paperboard material, the body wall defining an inner paperboard surface facing toward an interior of the container; and    an unsupported liner free of paper layers and adhered to the inner paperboard surface of the body wall via a wet adhesive interposed between the liner and the inner paperboard surface, the liner comprising a heat seal layer defining an innermost surface of the container, a barrier web attached to a radially outer surface of the heat seal layer, and a sealable primer applied as an aqueous dispersion to a radially outer surface of the barrier web and then dried, the sealable primer comprising a polymer having bonding affinity with the wet adhesive and furthermore being heat-sealable to the heat seal layer of the liner, the liner having opposite edges that form a lap joint therebetween via heat sealing of the heat seal layer to the sealable primer.    
     
     
         2 . The composite container of  claim 1 , wherein the sealable primer comprises a modified ethylene polymer.  
     
     
         3 . The composite container of  claim 1 , wherein the sealable primer is selected from the group consisting of modified ethylene polymers, modified acrylic primers, acrylic heat seal coatings, and vinyl primers/washcoats.  
     
     
         4 . The composite container of  claim 1 , wherein the heat seal layer comprises a layer of ionomer resin.  
     
     
         5 . The composite container of  claim 4 , wherein the ionomer resin comprises ethylene acid copolymer having acid groups partially neutralized by zinc or sodium ions.  
     
     
         6 . The composite container of  claim 4 , wherein the heat seal layer further comprises a layer of high-density polyethylene coextruded with the layer of ionomer resin.  
     
     
         7 . The composite container of  claim 1 , wherein the barrier web comprises metal foil.  
     
     
         8 . The composite container of  claim 1 , wherein the barrier web comprises metallized polymer film.  
     
     
         9 . An unsupported, lap-sealable liner for a composite container, the liner being free of paper layers and comprising: 
 a heat seal layer;    a barrier web having a first surface attached to the heat seal layer and having an opposite second surface; and    a sealable primer applied as an aqueous dispersion to the second surface of the barrier web and then dried, the sealable primer comprising a polymer having bonding affinity with wet adhesive used for bonding the liner to a paperboard surface of a composite container, the sealable primer furthermore being heat-sealable to the heat seal layer whereby the liner is lap-sealable.    
     
     
         10 . The unsupported, lap-sealable liner of  claim 9 , wherein the sealable primer comprises a modified ethylene polymer.  
     
     
         11 . The unsupported, lap-sealable liner of  claim 9 , wherein the sealable primer is selected from the group consisting of modified ethylene polymers, modified acrylic primers, acrylic heat seal coatings, and vinyl primers/washcoats.  
     
     
         12 . The unsupported, lap-sealable liner of  claim 9 , wherein the heat seal layer comprises a layer of ionomer resin.  
     
     
         13 . The unsupported, lap-sealable liner of  claim 12 , wherein the ionomer resin comprises ethylene acid copolymer having acid groups partially neutralized by zinc or sodium ions.  
     
     
         14 . The unsupported, lap-sealable liner of  claim 12 , wherein the heat seal layer further comprises a layer of high-density polyethylene coextruded with the layer of ionomer resin.  
     
     
         15 . The unsupported, lap-sealable liner of  claim 9 , wherein the barrier web comprises metal foil.  
     
     
         16 . The unsupported, lap-sealable liner of  claim 9 , wherein the barrier web comprises metallized polymer film.  
     
     
         17 . The unsupported, lap-sealable liner of  claim 9 , wherein the heat seal layer comprises a blow or cast film and is adhesively laminated to the barrier web.  
     
     
         18 . The unsupported, lap-sealable liner of  claim 9 , wherein the heat seal layer comprises an extrusion coating on the barrier web.  
     
     
         19 . A method of making an unsupported, lap-sealable liner for a composite container, comprising the steps of: 
 providing a barrier web having opposite first and second surfaces;    attaching a heat seal layer to the first surface of the barrier web; and    applying an aqueous dispersion of a sealable primer to the second surface of the barrier web and allowing the aqueous dispersion to dry such that a layer of the sealable primer covers the second surface of the barrier web, the sealable primer comprising a polymer having bonding affinity with wet adhesive used for bonding the liner to a paperboard surface of a composite container, the sealable primer furthermore being heat-sealable to the heat seal layer whereby the liner is lap-sealable.    
     
     
         20 . The method of  claim 19 , wherein the heat seal layer comprises a blow or cast sealant film, and the step of attaching the heat seal layer comprises adhesively laminating the sealant film to the barrier web.  
     
     
         21 . The method of  claim 19 , wherein the step of applying the aqueous dispersion comprises using a gravure roll to apply the aqueous dispersion onto the barrier web.  
     
     
         22 . The method of  claim 19 , wherein the step of attaching the heat seal layer comprises extrusion coating the heat seal layer onto the barrier web.  
     
     
         23 . The method of  claim 19 , wherein the sealable primer is selected from the group consisting of modified ethylene polymers, modified acrylic primers, acrylic heat seal coatings, and vinyl primers/washcoats.