Nylon barrier board structure

Abstract

A paperboard laminate useful for making gable top juice cartons is provided. The laminate provides for a high melting point polymer such as a semi-crystalline nylon to be applied directly to a board surface as an oxygen barrier layer. An anti-scalping layer is also provided by a polar polymer which is connected by a tie layer to an outermost skin coat layer. Positioned between the skin coat layer and the oxygen barrier layer are one or more bulk layers of polyolefins. The resulting laminate affords a juice carton which has good oxygen barrier and Vitamin C retention properties, is resistant to overactivation during heat sealing, has minimal scalping of d-limonene and essential oils, and has excellent bulge resistance.

1 . A laminate structure comprising: 
 a paperboard substrate having an inner surface and an outer surface;    a layer of a heat-sealable polymer coated on the outer surface of the paperboard substrate;    a semi-crystalline polyamide polymer layer coated on the inner surface of the paperboard substrate;    a first tie layer coated on an inner surface of the semi-crystalline polyamide polymer layer;    at least one layer of polyolefin polymer coated on an inner surface of the first tie layer;    a second tie layer positioned on an inner surface of the at least one layer of polyolefin polymer;    a polar polymer scalping barrier layer selected from the group consisting of a semi-crystalline nylon, an amorphous nylon, a polyester, and combinations thereof on an inner surface of the second tie layer;    a third tie layer positioned on an inner surface of the polar polymer scalping barrier layer; and,    a heat-sealable polymer layer coated on an inner surface of the third tie layer.    
   
   
       2 . The laminate structure according to  claim 1  wherein said semi-crystalline polyamide polymer layer further comprises a nylon selected from the group consisting of Nylon 4/6, Nylon 6/6, Nylon 6/12, Nylon 11, Nylon 12, and combinations thereof.  
   
   
       3 . The laminate structure according to  claim 1  wherein the polar polymer scalping barrier layer is a high melting point semi-crystalline polyamide.  
   
   
       4 . The laminate structure according to  claim 2  wherein said polar polymer scalping barrier layer comprises a high melting point semi-crystalline polyamide.  
   
   
       5 . The laminate structure according to  claim 1  wherein said semi-crystalline polyamide polymer layer and said polar polymer scalping barrier layer are Nylon 6.  
   
   
       6 . The laminate structure according to  claim 1  wherein said semi-crystalline polyamide polymer layer and said polar polymer scalping barrier layer is Nylon 6/6.  
   
   
       7 . The laminate structure according to  claim 1  wherein said at least one layer of polyolefin polymer on an inner surface of the first tie layer has a coating weight of about 12 to about 24 lbs/3,000 sq. ft.  
   
   
       8 . A laminate structure consisting essentially of: 
 a paperboard substrate having an inner surface and an outer surface;    a layer of a heat-sealable polymer coated on the outer surface of the paperboard substrate;    a semi-crystalline polyamide polymer layer coated on the inner surface of the paperboard substrate;    a first tie layer coated on an inner surface of the semi-crystalline polyamide polymer layer;    at least one layer of polyolefin polymer coated on an inner surface of the first tie layer;    a second tie layer positioned on an inner surface of the at least one layer of polyolefin polymer;    a polar polymer scalping barrier layer selected from the group consisting of a semi-crystalline nylon, an amorphous nylon, a polyester, and combinations thereof on an inner surface of the second tie layer;    a third tie layer positioned on an inner surface of the polar polymer scalping barrier layer; and,    a heat-sealable polymer layer coated on an inner surface of the third tie layer.