Method of fabricating bottle-shaped container of saturated polyester

A method of fabricating a bottle-shaped container from a preformed cylindrical piece of polyethylene terephthalate with a bottom, comprising:

• selecting a preformed piece with an intrinsic viscosity of more than 0.55,
• heating the piece to a temperature for orienting,
• loading the heated piece into the blowing mold which is heated at a temperature in the range between the glass transition temperature and the orientation temperature of the saturated polyester,
• biaxially orienting the piece by longitudinally orienting the piece and then laterally orienting it by introducing compressed air into the interior of the piece while said piece is contained in the mold until the outer wall of the piece comes into contact with the inner wall of the mold;
• the container expanded by said biaxially orienting step being thermally set by contact with the outer wall of the container with the inner wall of the mold retained at a temperature in the range between the glass transition temperature and the orientation temperature for a period of time in the range of six to eight seconds,
• opening the mold to unload and rapidly cool the container thus molded,
• said mold having a capacity upwardly adjusted by about 6% relative to the desired final capacity of said container, said blowing mold temperature being in the range of about 70.degree. C. to less than about 80.degree. C.