Gas-barrier containers

Abstract

A gas-barrier container having at least one gas-barrier layer, characterized in that the gas-barrier layer is made of a cured epoxy resin obtained by curing an epoxy resin composition mainly comprising an epoxy rein and a curing agent for epoxy resin and that the cured epoxy resin contains the skeletal structure of formula (1) in an amount of 30 wt % or above. The gas-barrier container exhibits high gas-barrier properties and a low environmental load by virtue of the use of a non-halogen gas-barrier material and is advantageous in economical efficiency and workability in production steps and excellent in interlaminar strength, gas-barrier properties under high humidity, impact resistance, and resistance to retorting, thus being usable as container for foods or drinks, packing material for drugs, and so on.

1 . A gas-barrier container comprising at least one gas-barrier layer made of an epoxy resin cured product that is formed by curing an epoxy resin composition mainly containing an epoxy resin and an epoxy resin-curing agent, and contains a skeletal structure represented by the formula (1):  
       
         
           
           
               
               
           
         
       
       in an amount of 30% by weight or higher.  
     
     
         2 . The gas-barrier container according to  claim 1 , wherein the gas-barrier layer has an oxygen permeability of 2 mL·mm/m 2 ·day·MPa or lower as measured at a temperature of 23° C. and a relative humidity of 60%.  
     
     
         3 . The gas-barrier container according to  claim 1 , wherein the epoxy resin contains, as a main component, at least one resin selected from the group consisting of epoxy resins containing glycidylamine moieties derived from m-xylylenediamine, epoxy resins containing glycidylamine moieties derived from 1,3-bis(aminomethyl)cyclohexane, epoxy resins containing glycidylamine moieties derived from diaminodiphenylmethane, epoxy resins containing glycidylamine moieties and/or glycidyl ether moieties derived from p-aminophenol, epoxy resins containing glycidyl ether moieties derived from bisphenol A, epoxy resins containing glycidyl ether moieties derived from bisphenol F, epoxy resins containing glycidyl ether moieties derived from phenol novolak, and epoxy resins containing glycidyl ether moieties derived from resorcinol.  
     
     
         4 . The gas-barrier container according to  claim 3 , wherein the epoxy resin contains as a main component, the epoxy resin containing glycidylamine moieties derived from m-xylylenediamine and/or the epoxy resin containing glycidyl ether moieties derived from bisphenol F.  
     
     
         5 . The gas-barrier container according to  claim 4 , wherein the epoxy resin contains, as a main component, the epoxy resin containing glycidylamine moieties derived-from-m-xylylenediamine.  
     
     
         6 . The gas-barrier container according to  claim 1 , wherein the epoxy resin-curing agent is a reaction product of the following components (A) and (B) or a reaction product of the following components (A), (B) and (C): 
 (A) m-xylylenediamine or p-xylylenediamine;    (B) a polyfunctional compound having at least one acyl group which is capable of forming amido moieties and, as a result, an oligomer by the reaction with m-xylylenediamine or p-xylylenediamine; and    (C) a C 1  to C 8  monocarboxylic acid and/or a derivative thereof.    
     
     
         7 . The gas-barrier container according to  claim 6 , wherein the epoxy resin-curing agent is a reaction product of m-xylylenediamine with acrylic acid, methacrylic acid and/or a derivative thereof.  
     
     
         8 . The gas-barrier container according to  claim 1 , wherein the container is produced by forming a gas-barrier laminated film or sheet containing at least one flexible polymer layer and at least one gas-barrier layer into a desired shape.  
     
     
         9 . The gas-barrier container according to  claim 8 , wherein the flexible polymer layer is a layer made of at least one thermoplastic resin selected from the group consisting of polyolefin-based resins, polyester-based resins, polyacrylonitrile-based resins, polystyrene-based resins and polyamide-based resins.  
     
     
         10 . The gas-barrier container according to  claim 8 , wherein at least one of the flexible polymer layers is a layer made of a heat-sealable polymer.  
     
     
         11 . The gas-barrier container according to  claim 8 , wherein a blending ratio between the epoxy resin and the epoxy resin-curing agent in the epoxy resin composition contained in the gas-barrier layer is controlled such that an equivalent ratio of active hydrogen contained in the epoxy resin-curing agent to epoxy groups contained in the epoxy resin is in the range of 1.5 to 3.0.  
     
     
         12 . The gas-barrier container according to  claim 8 , wherein the epoxy resin-curing agent contained in the gas-barrier layer is a reaction product of the following components (A) and (B) or a reaction product of the following components (A), (B) and (C) from which a part or whole of the unreacted component (A) is removed after the reaction between (A) and (B) or between (A), (B) and (C): 
 (A) m-xylylenediamine or p-xylylenediamine;    (B) a polyfunctional compound having at least one acyl group which is capable of forming amido moieties and, as a result, an oligomer by the reaction with m-xylylenediamine or p-xylylenediamine; and    (C) a C 1  to C 8  monocarboxylic acid and/or a derivative thereof.    
     
     
         13 . The gas-barrier container according to  claim 1 , wherein the container is in the form of a hollow container in which 60 to 100% of a surface area of at least one of an outer surface and an inner surface thereof is coated with the gas-barrier layer.  
     
     
         14 . The gas-barrier container according to  claim 13 , wherein the hollow container is formed from a layer made of at least one thermoplastic resin selected from the group consisting of polyolefin-based resins, polyester-based resins, polyacrylonitrile-based resins, polystyrene-based resins and polyamide-based resins.  
     
     
         15 . The gas-barrier container according to  claim 2 , wherein the epoxy resin contains, as a main component, at least one resin selected from the group consisting of epoxy resins containing glycidylamine moieties derived from m-xylylenediamine, epoxy resins containing glycidylamine moieties derived from 1,3-bis(aminomethyl)cyclohexane, epoxy resins containing glycidylamine moieties derived from diaminodiphenylmethane, epoxy resins containing glycidylamine moieties and/or glycidyl ether moieties derived from p-aminophenol, epoxy resins containing glycidyl ether moieties derived from bisphenol A, epoxy resins containing glycidyl ether moieties derived from bisphenol F, epoxy resins containing glycidyl ether moieties derived from phenol novolak, and epoxy resins containing glycidyl ether moieties derived from resorcinol.  
     
     
         16 . The gas-barrier container according to  claim 15 , wherein the epoxy resin-curing agent is a reaction product of the following components (A) and (B) or a reaction product of the following components (A), (B) and (C): 
 (A) m-xylylenediamine or p-xylylenediamine;    (B) a polyfunctional compound having at least one acyl group which is capable of forming amido moieties and, as a result, an oligomer by the reaction with m-xylylenediamine or p-xylylenediamine; and    (C) a C 1  to C 8  monocarboxylic acid and/or a derivative thereof.    
     
     
         17 . The gas-barrier container according to  claim 3 , wherein the epoxy resin-curing agent is a reaction product of the following components (A) and (B) or a reaction product of the following components (A), (B) and (C): 
 (A) m-xylylenediamine or p-xylylenediamine;    (B) a polyfunctional compound having at least one acyl group which is capable of forming amido moieties and, as a result, an oligomer by the reaction with m-xylylenediamine or p-xylylenediamine; and    (C) a C 1  to C 8  monocarboxylic acid and/or a derivative thereof.    
     
     
         18 . The gas-barrier container according to  claim 17 , wherein the container is in the form of a hollow container in which 60 to 100% of a surface area of at least one of an outer surface and an inner surface thereof is coated with the gas-barrier layer.  
     
     
         19 . The gas-barrier container according to  claim 6 , wherein the container is in the form of a hollow container in which 60 to 100% of a surface area of at least one of an outer surface and an inner surface thereof is coated with the gas-barrier layer.