Injection-molded body of olefin/vinyl alcohol copolymer and process for preparation thereof

An injection-molded body obtained by injecting a melt of an olefin/vinyl alcohol copolymer into a cooled mold through an injection nozzle, wherein the olefin/vinyl alcohol copolymer in the injection-molded body has a weight average molecular weight (Mw) of at least 80,000 and a molecular weight distribution (Mw/Mn) of at least 2.1.

An injection-molded body which comprises an ethylene/vinyl alcohol copolymer having a weight average molecular weight (Mw) of at least 80,000 and a molecular weight distribution (Mw/Mn) of at least 2.1, said molded body being obtained by melt-kneading a composition comprising (i) a high-molecular-weight olefin/vinyl alcohol copolymer having a melt flow rate of 0.4 to 6.0 g/10 min as determined at 190.degree. C. and a vinyl alcohol content of 40 to 80 mole % and (ii) a low-molecular-weight olefin/vinyl alcohol copolymer having a melt flow rate of 3.0 to 60 g/10 min as determined at 190.degree. C., which is higher by at least 0.5 g/10 min than that of the high-molecular-weight ethylene/vinyl alcohol copolymer (i), and a vinyl alcohol content of 45 to 85 mole %, at a weight ratio of from 98/2 to 40/60, and injecting the melt-kneaded composition into a mold through a nozzle.

A multi-layer injection-molded body which comprises inner and outer layers of a creep-resistant thermoplastic resin and an intermediate layer of an ethylene/vinyl alcohol copolymer, wherein the ethylene/vinyl alcohol copolymer has a weight average molecular weight (Mw) of at least 80,000 and a molecular weight distribution (Mw/Mn) of at least 2.1.

A multi-layer injection-molded body comprising inner and outer layers of a creep-resistant thermoplastic resin and an intermediate layer of an olefin/vinyl alcohol copolymer, which is obtained by simultaneously or sequentially injecting the olefin/vinyl alcohol copolymer and the creep-resistant thermoplastic resin, wherein the olefin/vinyl alcohol copolymer in the multi-layer injection-molded body has a weight average molecular weight (Mw) of at least 80,000 and a molecular weight distribution (Mw/Mn) of at least 2.1.