Method for blow molding plastic articles

A method for forming a molecularly oriented thermoplastic container, wherein a thermoplastic blowable shape such as a parison or a blown pre-form is blown to the configuration of the container within a blow mold cavity. The temperature of the blowable shape is within a range conducive to molecular orientation during the blowing step, which is rapidly performed by hot blow air at a temperature between about 100 DEG to 400 DEG F. Typically, a blowable shape formed of polyethylene terephthalate is blown while the shape is at a temperature within the range of 165 DEG to 200 DEG F. by the introduction into the shape of hot blow air at a temperature within the range of about 165 DEG to 200 DEG F. If desired, the blowable plastic shape may be axially stretched mechanically in addition to being blown in order to improve the biaxial orientation of the thermoplastic material in the final article.