Extrusionblown

Extrusionblown refers to a manufacturing technique that combines extrusion and blow molding, commonly employed in the production of plastic bags, containers, and a variety of hollow shapes. The process begins with the extrusion of a polymer melt through a circular die, forming a tube or “parison” of molten plastic. The extruded parison is then cooled and cut into sections, each of which is inserted into a mold cavity. High‑pressure air is introduced into the interior of the parison, expanding it against the mold walls. Once the polymer solidifies, the mold is opened, and the fully formed product is ejected. This method allows for continuous, high‑volume production while maintaining precise dimensional control and complex shapes.

Extrusionblown is favored in packaging due to its speed, low energy consumption, and minimal waste generation. It is utilized primarily with polyethylene (PE) and polypropylene (PP) but can also accommodate certain nylon blends and PVC grades. Typical end products include disposable grocery bags, trash bags, food storage pouches, and flotation devices. Because the resulting items are lightweight and possess good barrier properties, the method is widely adopted in both consumer and industrial markets.

Advantages of extrusionblown include rapid cycle times, the ability to produce one‑piece closures (e.g., flip‑top or zip‑lock), and the potential for integrated features such as heat seals and printing directly onto the bag surface. However, the process requires careful temperature regulation to avoid instability in the melt and can suffer from limited thickness range compared to injection molding. Still, the combination of cost‑efficiency and product diversity keeps extrusionblown a staple in polymer manufacturing.