Film Manufacturing and Technology
Below is a brief
explanation of the standard extrusion process used in manufacturing polyester
- Polyester polymer grades
(made in continuous process or batch reactors) are extruded onto casting
drum (gives ultra smooth surface to plastic film).
- Film is stretched in forward
and transverse directions.
- Two-stage process: first
forward draw is over series of precision motorized rollers, sideways
draw uses clips in main multiple oven where film is heated in tightly
controlled temperature zones.
- Most advanced technology
uses simultaneous forward and sideways draw.
- In all processes, tension
and temperatures are critical to final quality of film.
- Sophisticated scanners and
control systems maintain process conditions at optimal point.
- Advanced structures are
made by extruding layers of polymer simultaneously and coating film
as it is stretched.
- Film is wound into large
master rolls (can be slit to precision widths before delivery to customer).
- Film thicknesses typically
range from 1 micron to 350 microns.
- Each asset usually designed
for narrow range of thicknesses.
- Offering complete range
of films requires heavy investment in multiple lines (from $50 million