Stretch blow molding process and apparatus for the manufacturing of plastic containers

摘要

A stretch blow molding process and apparatus for the manufacturing of plastic containers includes the step of preheating the preform. In particular the preheating step includes directly heating the inside of the preform. This is particularly important during the processing of polypropylene. The method for heating plastic preforms for the stretch blow molding thereof comprises the steps of heating the outside of the preforms with at least one infrared radiation lamp and directly heating the inside of the preforms. Preferably the heating of the outside and the heating of the inside is performed concurrently. The apparatus for use in the preheat step of a preform during a stretch blow molding process includes a channel; a plurality of chucks and a method of directly heating the inside of the preforms. The plurality of chucks are movably connected to the channel and each chuck is adapted to receive a preform. The inside of the preform is heated as the chuck moves along the channel. The inside of the preform may be directly heated by blowing hot air into the preform, inserting a calory or infrared rod inside the preform or a combination of both.