Bio-oriented Film (BOPP)

Biaxial orientation consists on stretching the polypropylene film in two perpendicular directions, the film is longitudinally stretched in the direction of the machine and it is then stretched in its transversal direction; this action provides a high orientation and excellent tensile properties in both directions.

The BOPP film is used for packing cookies, candies, spices, coffee, pastas, cigarettes, boxes of video cassettes and adhesive tapes, among others.

Cast and tubular (TWQ) films

The Cast film is obtained by the extrusion of a sheet which (still in its melting state) contacts a cold metal roll (chill roll), where it solidifies.   In the TWQ (tubular water quenching) process a polypropylene tube is extruded downwards as air is injected inside and it is covered with cold water.

A comparison of both processes is shown in the following table.

Table 1. Comparison between the cast film and TWQ processes in polypropylene.

Property Cast Tubular Transparency + + Stiffness - + Toughness - + Barrier - + Thickness Uniformity + -

Films obtained through these processes are mainly used for packages containing food, flour, coffee, grains and flower wrappings.

GRADE APPLICATIONS I.F. M.F. R.I. Detail F600 Extrusion. Tubular water quenched film. 8 1500 25 F605 Extrusion. Cast Film. 10 1500 30 F651 Extrusion. General Purpose for cast, BOPP and TWQ films. 7 900 65