Blåsefilmproduksjon

Blåsefilmproduksjon, or blown film extrusion, is a manufacturing process used to create plastic films. It involves melting plastic pellets and then forcing the molten plastic through a circular die, forming a hollow tube. This tube is then inflated with air, much like a balloon, which stretches the plastic radially and axially, thinning it to the desired thickness. As the tube rises and cools, it is flattened into a lay-flat tube or slit into individual sheets.

The process begins with raw plastic resin, typically polyethylene (PE) or polypropylene (PP), which is fed into an extruder. The extruder heats and melts the plastic, homogenizing it before it is pushed through the die. The diameter of the die and the amount of air introduced into the bubble control the film's width and thickness. The bubble is then cooled, often by a water bath or air rings, to solidify the plastic. Finally, the bubble is collapsed and wound onto rolls or cut to size.

Blown film is widely used for packaging applications due to its strength, flexibility, and puncture resistance. Common examples include plastic bags, agricultural films, shrink wrap, and industrial liners. The process allows for the production of films with excellent biaxial orientation, meaning the polymer chains are aligned in both directions, contributing to the film's strength and tear resistance. Adjustments in processing parameters like melt temperature, blow-up ratio, and cooling rate allow for tailoring the film's properties for specific end uses.