Molded container having wall composed of oriented resin blend

A molded container having a wall composed of a thermoplastic resin oriented in at least one direction on the wall face, wherein the container wall has a multi-layer structure including at least one layer of a blend composed of a plurality of melt-extrudable thermoplastic resins, each of said thermoplastic resins having a solubility parameter (Sp) of at least 9.5 and at least one layer composed of a moisture-resistant thermoplastic resin having a moisture permeability lower than 100.times.10.sup.-12 g.multidot.cm/cm.sup.2 .multidot.sec.multidot.cmHg as measured at a temperature not exceeding 50.degree. C., each of said thermoplastic resins in said blend layer having an oxygen permeability lower than 5.times.10.sup.-11 cc.multidot.cm/cm.sup.2 .multidot.sec.multidot.cmHg, one (A) of said thermoplastic resins being an ethylene-vinyl alcohol copolymer having an ethylene content of 25 to 50 mole %, another (B) of said thermosplastic resins in said blend layer including at least one member selected from the group consisting of homopolyamides and copolyamides having 3 to 30 amide groups per 100 carbon atoms in the molecule, said blend being one formed by mixing said resin (A) and said resin (B) at a weight ratio (A):(B) of from 90:10 to 10:90 with the difference (.DELTA.Sp) of the solubility parameter in said thermoplastic resins being not greater than 4.5 and the elongation of said resin blend being higher than the arithmetric mean (.epsilon.) of elongations of the respective thermoplastic resins in the resin blend, said moisture-resistant thermoplastic resin being a polyolefin or a copolymer of an olefin with a carbonyl group-containing ethylenically unsaturated monomer, the multi-layer structure including an inner layer of said moisture-resistant thermoplastic resin, an intermediate layer of said blend and an outer layer of said moisture-resistant thermoplastic resin, said multi-layer structure has an interlaminar bonding strength of at least 20 g/cm, and said multi-layer structure having been molecularly oriented so that said structure has a thermal shrinkability (.delta.) of at least 5% in the orientation direction of said container wall.

A container formed by biaxial draw-blow molding of a parison composed of a thermoplastic resin, said parison having a multi-layer structure including at least one layer of a blend composed mainly of a plurality of melt-extrudable thermoplastic resins, each melt-extrudable thermoplastic resin having a solubility parameter (Sp) of at least 9.5, and at least one layer composed of a creep-resistant thermoplastic resin in which the sum of the instantaneous modulus (Eg) and retardation modulus (E.sub.1) at a temperature of 23.degree. C. and a stress of 7.times.10.sup.7 dyne/cm.sup.2 is at least 1.times.10.sup.10 dyne/cm.sup.2 and which has a steady state flow viscosity (.eta..sub..infin.) of at least 1.times.10.sup.17 poise and a retardation time (t.sub.R) shorter than 6.times.10.sup.6 sec, each of said thermoplastic resins in said blend having an oxygen permeability lower than 5.times.10.sup.-11 cc.multidot.cm/cm.sup.2 .multidot.sec.multidot.cmHg, one (A) of said thermoplastic resins in said blend being an ethylene-vinyl alcohol copolymer having an ethylene content of 25 to 50 mole %, another (B) of said thermoplastic resins in said blend including at least one member selected from the group consisting of homopolyamides and copolyamides having 3 to 30 amide groups per 100 carbon atoms in the molecule, said blend being one formed by mixing said resin (A) and said resin (B) at a weight ratio (A):(B) of from 90:10 to 10:90, with the difference (.DELTA.Sp) of the solubility parameter in said thermoplastic resins being not greater than 4.5 and the elongation of said resin blend being higher than the arithmetric mean (.epsilon.) of elongations of the respective thermoplastic resins in the resin blend, the creep-resistant thermoplastic resin being a member selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polycarbonates, acrylonitrile-butadiene-styrene resins, acrylonitrile-styrene resins, polyacetals, polyamides, polymethyl methacrylate, isotactic polypropylene, polystyrene, polyacrylates, polyphenylene oxide and polysulfones, and wherein said molded container is molecularly oriented so that said container has a thermal shrinkability (.delta.) of at least 5% in the orientation direction of said container wall.

A container formed by draw molding of a film or sheet composed of a thermoplastic resin, said film or sheet having a multi-layer structure including at least one layer of a blend composed mainly of a plurality of melt-extrudable thermoplastic resins, each of said melt-extrudable thermoplastic resins having a solubility parameter (Sp) of at least 9.5, and at least one layer composed of a creep-resistant thermoplastic resin in which the sum of the instantaneous modulus (Eg) and retardation modulus (E.sub.1) at a temperature of 23.degree. C. and a stress of 7.times.10.sup.7 dyne/cm.sup.2 is at least 1.times.10.sup.10 dyne/cm.sup.2 and which has a steady state flow viscosity (.eta..sub..infin.) of at least 1.times.10.sup.17 poise and a retardation time (t.sub.R) shorter than 6.times.10.sup.6 sec., each of said thermoplastic resins in said blend having an oxygen permeability lower than 5.times.10.sup.-11 cc.multidot.cm/cm.sup.2 .multidot.sec.multidot.cmHg, one (A) of said thermoplastic resins in said blend being an ethylene-vinyl alcohol copolymer having an ethylene content of 25 to 50 mole %, another (B) of said thermoplastic resins in said blend including at least one member selected from the group consisting of homopolyamides and copolyamides having 3 to 30 amide groups per 100 carbon atoms in the molecule, said blend being one formed by mixing said resin (A) and said resin (B) at a weight ratio (A):(B) of from 90:10 to 10:90 with the difference (.DELTA.Sp) of the solubility parameter in said thermoplastic resins being not greater than 4.5 and the elongation of said resin blend being higher than the arithmetric mean (.epsilon.) of elongations of the respective thermoplastic resins in the resin blend, the creep-resistant thermoplastic resin being a member selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polycarbonates, acrylonitrile-butadiene-styrene resins, acrylonitrile-styrene resins, polyacetals, polyamides, polymethyl methacrylate, isotactic polypropylene, polystyrene, polyacrylates, polyphenylene oxide and polysulfones, said multi-layer structure having an interlaminar bonding strength of at least 20 g/cm, and wherein said molded container is molecularly oriented so that said container has a thermal shrinkability (.delta.) of at least 5% in the orientation direction of said container wall.