Container Having Barrier Properties and Method of Manufacturing the Same

Abstract

A method of manufacturing a multilayer or a monolayer plastic container is disclosed. The container has a barrier layer manufactured from (i) a polyester resin, preferably an aromatic polyester resin such as a polyethylene terephthalate, (ii) a polyamide material, preferably an aromatic polyamide material, and (iii) an oxygen scavenging material, preferably a transition method. The present invention also provides containers having a multilayer or a monolayer body. In the preparation of the barrier layer. a preform first is prepared by an injection-molding process wherein a preblend containing a diluent polyester, polyamide material, and an oxygen scavenging material is added to a base polyester during the injection molding process. The preform then is expanded to form a container.

1 - 33 . (canceled) 
     
     
         34 . A plastic container, comprising:
 an extruded or injection molded container having a barrier layer formed from a melt blended admixture of a base polyester and a preblend, the preblend comprising:
 a diluent polyester, 
 a polyamide material that comprises a polymer containing m-xylylenediamine monomer units, p-xylylenediamine monomer units, or a mixture thereof, and 
 cobalt or a complex or salt thereof present in the preblend an amount of 20 to 2,000 parts per million by weight; and 
   wherein the plastic container is stable during unfilled storage and the barrier layer has an oxygen scavenging property that is activated after filling the container with an aqueous fluid, and wherein activation results from filling.   
     
     
         35 . The plastic container of  claim 34 , wherein the plastic container comprises a monolayer plastic container. 
     
     
         36 . The plastic container of  claim 34 , wherein the plastic container comprises a multilayer plastic container. 
     
     
         37 . The plastic container of  claim 36 , wherein the barrier layer has a thickness of between about 1 and 10 percent of the total container wall thickness. 
     
     
         38 . The plastic container of  claim 36 , wherein the plastic container includes an inner layer and an outer layer in addition to the barrier layer. 
     
     
         39 . The plastic container of  claim 36 , wherein the inner and outer layers each comprise a polyethylene terephthalate layer. 
     
     
         40 . The plastic container of  claim 34 , wherein plastic container includes a five-layer structure. 
     
     
         41 . The plastic container of  claim 34 , wherein the plastic container comprises a soft drink bottle. 
     
     
         42 . The plastic container of  claim 34 , further including a food or beverage product packaged therein. 
     
     
         43 . The plastic container of  claim 42 , wherein the food or beverage product comprises beer, a citrus product, a tomato-based product, or an aseptically packaged meat. 
     
     
         44 . The plastic container of  claim 34 , wherein the plastic container comprises a preform that includes about 10 to about 80 ppm, by weight, of cobalt or a salt or complex thereof. 
     
     
         45 . The plastic container of  claim 34 , wherein the diluent polyester comprises a homopolymer or a copolymer of a polyethylene terephthalate, a polyethylene naphthalate, a polybutylene terephthalate, a cyclohexane dimethanol/polyethylene terephthalate copolymer, or a mixture thereof. 
     
     
         46 . The plastic container of  claim 34 , wherein the base polyester is a virgin bottle grade polyester and the admixture consists essentially of the base polyester and the preblend. 
     
     
         47 . The plastic container of  claim 34 , wherein the polyamide material comprises a polymerization product of m-xylyenediamine and adipic acid. 
     
     
         48 . The plastic container of  claim 34 , wherein the preblend and the base polyester are admixed in an amount of 0.5% to 20%, by weight, of the preblend, and 80% to 99.5%, by weight, of the base polyester. 
     
     
         49 . The plastic container of  claim 48 , wherein the cobalt or a salt or complex thereof is present in the preblend in an amount of about 100 to about 1,000 parts per million. 
     
     
         50 . The plastic container of  claim 34 , wherein the preblend comprises about 30% to about 70%, by weight, of the diluent polyester comprising a polyethylene terephalate, a polyethylene naphthalate, or a mixture thereof; about 30% to about 70%, by weight, of the polyamide material; and about 50 to about 1500 ppm, by weight, of cobalt or a salt or complex thereof. 
     
     
         51 . The plastic container of  claim 34 , wherein the base polyester and the diluent polyester are each independently selected from a polyethylene terephthalate, a polynaphthalene terephthalate, a polybutylene terephthalate, a cyclohexane dimethanol/polyethylene terephthalate copolymer, or a mixture thereof. 
     
     
         52 . The plastic container of  claim 34 , wherein the plastic container has an oxygen permeability of 0.035 cc O 2 /package/day or less after filling with water for 48 hours. 
     
     
         53 . The plastic container of  claim 34 , wherein the plastic container has an oxygen permeability in cc O 2 /package/day after filling with water for 48 hours, that is less than the oxygen permeability of the container prior to filling with water, and wherein activation of oxygen-scavenging results from filling.