US 4,535,901 AGranted

Blow-molded multi-ply vessel

AssigneeToyo Boseki Kabushiki Kaisha

InventorsTadashi Okudaira, Akio Tsuboi, Yoshihisa Hama, Mamoru Hara

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Abstract

A blow-molded multi-ply vessel having excellent physical properties and good appearance which comprises two or more kinds of thermoplastic resins, at least one of which is a thermoplastic polyester resin, said vessel having a multi-ply structure of three or more layers at least at the thin wall part of the body thereof and a single layer structure at least at the open end of the mouth part thereof, and at least the thin wall part of the body being biaxially orientated. The vessel is produced by sequently and alternatively injecting two or more kinds of molten thermoplastic resins into one mold with shifting injection timing from a molding machine having plural injection cylinders with one mold closing operation to form a multi-ply parison and then blow-molding the parison at an orientating temperature.

Claims6

Dependent claims

A blow-molded multi-ply vessel having an open end mouth part and a thin wall part, which comprises:

a multi-ply structure of three or more odd-numbered layers at least at the thin wall part;
two or more kinds of thermoplastic resins, at least one of which being a thermoplastic polyester resin mainly composed of the repeating units of ethylene terephthalate;
the innermost and the outermost layers of said multi-ply structure being composed of said thermoplastic polyester resin;
at least one of the middle layers of said multi-ply structure being composed of a thermoplastic resin the main component of which is a resin selected from the group consisting of a polyamide resin, a polymer having a high nitrile content, an ethylene/vinyl alcohol copolymer, a polyolefin resin, a polyacrylic resin, a polyvinyl chloride resin, a polycarbonate resin and a polystyrene resin;
said innermost and outermost layers extending over the entire inside and outside surfaces of said vessel and being integrated at least at the open end mouth part to form a single layer structure of said thermoplastic polyester resin to wrap the middle layers;
and
at least the thin wall part being biaxially oriented.

4 more elements

Dependencies are inferred from the claim text.