Contactless simultaneous biorientation

In order to produce biaxially oriented shrink films, GAP has developed the new Simultaneox range of systems based on the double bubble technology, enabling the contactless simultaneous bi-orientation of films. These systems make it possible to manufacture 5- to 11-layer films with widths ranging from 500 to 2000 mm, reducing their overall thickness through the orientation process while preserving their barrier and transparency properties.
The double bubble technology involves the extrusion of polymers through a circular head and their immediate cooling down with water in order to obtain a first tubular film. This film is then heated until it reaches a temperature suitable for the orientation process, and then blown so as to create the main thin film bubble. The contactless simultaneous orientation technique takes advantage of the air introduced at the beginning of the production process in order to blow the tubular film, thus obtaining a volume increase and, as a result, a transversal orientation (transverse direction - TD) of the film, while a longitudinal orientation (machine flow direction - MD) is obtained by varying firstly the operating speed and, secondly, the orientation zone itself. The film bubble is then cooled down with air, then collapsed and trimmed in order to achieve the final width. The shrink film manufactured with this process is finally wound in two bobbins.
The extruder can be equipped with an in-line stabilisation system using an additional bubble, a tenter or a set of rolls. The in-line stabilisation process makes it possible to obtain a partially stabilised film suitable for lid applications.
The Simultaneox range enables the production of biaxially oriented polyolefin shrink films, with the possibility to perform a cross-link irradiation, destined for the manufacturing of conventional packaging for a wide range of items (boxes for toys, chocolate packaging, CDs etc.), or barrier films up to 11 layer based on PA and EVOH matrixes for food packaging (meat, counter products etc.). For the latter items, the company offers a multilayer barrier film line for R&D and pre-marketing activities, used in particular to manufacture shrink barrier bags and films or oriented films for lid applications.