February 21st, 2009Manufacturing process of Mylar sheets
Mylar is a plastic film that is used for its intense strength. The process of its manufacturing starts with a layer of melt Polyethylene Terephthalate (PET) that is been extruded on a cool roll, which extinguish it into a shapeless state. It is been then biaxially leaned by drawing Mostly this is been done through sequential process, in this firstly we draw the film in the direction of machine by the help of heated rollers and then it is been drawn in the other direction. It is also been expected to draw it in both the directions concurrently, though the equipment necessary for this is rather more complicated. Drawing ratios are usually about 3 to 4 in every direction.
Once this process is been completed, the film is then crystallized in the oven at a temperature of more than 200 °C. This step stops the film from reducing back to its real outstretched form and it locks the molecular direction in film plane. The direction of the chains of polymer is the reason for the stiffness and high strength of Mylar. The most significant effect of the molecular is that it encourages the creation of various crystal nuclei.
