Patent ID: 6406661
Filing Date: 2002-06-18
Classification: B29C,B29K,Y10S

Abstract:
A heat set blow molding process, comprising:providing a plastic preform; thermally conditioning the preform, to achieve a temperature profile across the wall of the preform wherein the inner surface of the preform is at a higher temperature than the outer surface of the preform, said temperature profile being within the molecular orientation temperature range of the plastic; heating the outer surface of the preform, to increase the temperature of the outer surface of the preform by at least about 10Â° C.; enclosing the preform in a hot mold; expanding the preform to form a container within the hot mold, by introducing a blowing fluid into the preform to induce biaxial orientation in the expanded preform upon stretching and force the expanded preform into conforming contact with the hot mold; and maintaining the expanded preform in conforming contact with the hot mold for a time sufficient to induce at least partial crystallization of the plastic material and to cool and to make rigid the inner surface of the expanded preform.