It is the process by which hollow parts are molded by expanding the semi-molted polypropylene against the internal surface of a mold. The process includes the extrusion of a resin tube or Parison downwards between the open walls of a mold, which is later closed; both the upper and lower parts of the Parison are then cut or sealed off. Afterwards, air is injected inside the Parison with the help of a metallic insert which has been specially designed for this purpose. The resin acquires the shape of the mold, after which it is cooled down and removed from the mold.

Among the most common applications of this process we can find: bottles for milk, juices, mineral water, detergents, serums and large bottles for mineral water, among others.

enlarge the image