PET - Injection Stretch Blow Molding

The first part of the lesson describes the chemical and molecular structure of PET. The description of molecular chains is necessary to understanding the viscosity of the resin. The course covers the importance of the crystallinity of the preform as it transitions from preform to blown bottle. Two types of crystallinity are also described as the preform is heated and blown. This lesson takes a close look at the goals of the blow molding process; to create a bottle with strength, clarity, and uniform consistency.

The second part of the lesson describes the conditions that affect raw materials and includes a detailed description of the injection molding machine conditions that will affect the preform. Plastic temperature, pressure and cooling rate all have key importance to crystallinity control of the preform. Factors that will help reduce crystallinity formation in the preform are also discussed.