Plastic container

Abstract

Disclosed is a plastic container having a wall comprising a layer made of a composition comprising a major amount of crystalline propylene-ethylene-butene-1 copolymer which has specific structural unit proportions and a specific melt flow rate and a minor amount of ethylene-α-olefin copolymer which has specific structural unit proportions, a specific melt flow rate and a specific density, the container being superior in flexibility, impact strength at low temperatures anddurability.

1 . A plastic container having a wall comprising a layer made of a composition comprising from 70 to 99 parts by weight of a crystalline propylene-ethylene-butene-1 copolymer having features [1] and [2] defined below and from 1 to 30 parts by weight of an ethylene-α-olefin copolymer having features [3], [4]and [5], where the combined amount of both copolymers is 100 parts by weight: 
 [1] to have a content of propylene-derived structural units of from 70 to 97% by weight, a content of ethylene-derived structural units of from 1 to 10% by weight and a content of butene-1-derived structural units of from 2 to 20% by weight,    [2] to have a melt flow rate, measured at a temperature of 230° C. and a load of 2.16 kgf, of from 1 to 10 g/10 min,    [3] to be a copolymer of ethylene and an α-olefin having from 4 to 12 carbon atoms, the copolymer having a content of ethylene-derived structural units of 50% by weight or more,    [4] to have a melt flow rate, measured at a temperature of 190° C. and a load of 2.16 kgf, of from 0.1 to 50 g/10 min, and    [5] to have a density of from 865 to 898 kg/m 3 .    
     
     
         2 . The container according to  claim 1 , wherein the propylene-ethylene-butene-1 copolymer satisfies formula (1) defined below: 
           x +1 <y   (1) 
       wherein x denotes a content (% by weight) of ethylene-derived structural units and y denotes a content (% by weight) of butene-1-derived structural units.  
     
     
         3 . The container according to  claim 1  or  2 , wherein the wall is composed of a single layer made of the composition.  
     
     
         4 . The container according to  claim 1  or  2 , wherein the wall is composed of two or more layers including at least one layer made of the composition.  
     
     
         5 . The container according to  claim 1  or  2 , wherein the container is obtained by extrusion blow molding.  
     
     
         6 . The container according to  claim 1  or  2 , wherein the container is a container for medical use.