Injection molded body having excellent barrier property

Abstract

A multilayer injection molded article comprising a layer of a barrier resin composition including (A) 10 to 70% by mass of a polyamide resin including a diamine constitutional unit 70 mol % or more of which is derived from m-xylylenediamine and a dicarboxylic acid constitutional unit 70 mol % or more of which is derived from a dicarboxylic acid containing a C 4 to C 20 α,ω-linear aliphatic dicarboxylic acid and isophthalic acid at a molar ratio of from 30:70 to 100:0, (B) 90 to 30% by mass of a modified polyolefin, and the like.

1 . An injection molded article comprising:
 a multilayer structure comprising at least one layer comprising a barrier resin composition comprising (A) 10 to 70% by mass of a polyamide resin comprising a diamine unit 70 mol % or more of which is one or more m-xylylenediamine units and a dicarboxylic acid unit 70 mol % or more of which is one or more dicarboxylic acid units comprising a C 4  to C 20  α,ω-linear aliphatic dicarboxylic acid and isophthalic acid at a molar ratio of from 30:70 to 100:0; (B) 90 to 30% by mass of a modified polyolefin; and (C) 0 to 50% by mass of a polyolefin.   
     
     
         2 . An injection molded article comprising:
 (A) 10 to 60% by mass of a polyamide resin comprising a diamine unit 70 mol % or more of which is one or more m-xylylenediamine units and a dicarboxylic acid unit 70 mol % or more of which is one or more dicarboxylic acid units comprising a C 4  to C 20  α,ω-linear aliphatic dicarboxylic acid and isophthalic acid at a molar ratio of from 30:70 to 100:0; and   (E) 40 to 90% by mass of a mixed polyolefin comprising (C) 40 to 100% by mass of a polyolefin and (B) 0 to 60% by mass of a modified polyolefin,   wherein at least a part of the polyamide resin (A) is dispersed in a layered state.   
     
     
         3 . The injection molded article according to  claim 1 , wherein the polyamide (A) has a relative viscosity of 2.5 or more as measured at 25° C. in 96% by mass concentrated sulfuric acid as a solvent with a concentration of 1 g/100 mL. 
     
     
         4 . The injection molded article according to  claim 1 , wherein the modified polyolefin (B) is obtained by graft-modifying the polyolefin (C) with an unsaturated carboxylic acid or an anhydride thereof. 
     
     
         5 . The injection molded article according to  claim 1 , further comprising thermoplastic resin layers (F), wherein the layer comprising the barrier resin composition is sandwiched between thermoplastic resin layers (F) each made of a polyolefin. 
     
     
         6 . The injection molded article according to  claim 1 , wherein the article is a multilayer stretched injection molded article obtained by subjecting a multilayer injection molded article to biaxial stretch blow molding. 
     
     
         7 . The injection molded article according to  claim 1 , wherein the barrier resin composition comprises the polyolefin (C) comprising at least one selected from the group consisting of a homopolymer of an ethylenically unsaturated hydrocarbon having 2 to 8 carbon atoms, a homopolymer of an α-olefin having 3 to 20 carbon atoms, a copolymer of an α-olefin having 3 to 20 carbon atoms, and a copolymer of an α-olefin having 3 to 20 carbon atoms with a cyclic olefin. 
     
     
         8 . The injection molded article according to  claim 1 , wherein the resin composition comprises the polyolefin (C) comprising at least one selected from the group consisting of polyethylene, polypropylene, and 1-polybutene. 
     
     
         9 . The injection molded article according to  claim 1 , wherein the resin composition comprises the polyolefin (C) having a melt flow rate of from 1 to 100 g/10 min as measured at 190° C. under a load of 2.16 kgf. 
     
     
         10 . The injection molded article according to  claim 2 , wherein the modified polyolefin (B) is obtained by graft-modifying the polyolefin (C) with an unsaturated carboxylic acid or an anhydride thereof. 
     
     
         11 . The injection molded article according to  claim 2 , wherein the mixed polyolefin (E) comprises (C) 50 to 90% by mass of a polyolefin and (B) 10 to 50% by mass of a modified polyolefin.