Process for the production of oriented hollow bodies

Claim 1

In a process for the production of an oriented hollow body of thermoplastic material provided with a neck finish composed of an upper molded part having an axially symmetrical outer surface and presenting an orifice collar and a lower molded part, by initially blow molding a hot tubular parison of thermoplastic material in a preform mold to produce a preform, conveying the preform from the preform mold to a final blow mold, thermally conditioning the resulting preform to a temperature capable of inducing orientation of the thermoplastic material during subsequent stretching, and finally blow molding the preform to produce the desired final hollow body, the improvement wherein said step of initially blow molding is carried out in a manner to give only the orifice collar its definitive form and to produce a false neck located above the orifice collar, said step of conveying is effected in a manner to allow the preform to assume any arbitrary orientation about its longitudinal axis during introduction into the final blow mold, and said step of finally blow molding is carried out in a manner to form the lower molded part of the neck finish below the orifice collar.