Cooling Draw ratios

Cast film extrusion. In a cast film extrusion process, a thin film is extruded through a slit onto a chilled, highly polished, turning roll where it is quenched from one side. The speed of the roller controls the draw ratio and final film thickness. The film is then sent to a second roller for cooling of the other side. Finally, the film passes through a system of rollers and is wound onto a roll. A typical film casting process is depicted in Figs. 3.53... 

Fig. 9. Draw ratio as a function of time of draw for quenched (open circles) and slow-cooled (solid circles) LPE samples...

Fig. 10. Modulus versus draw ratio for a variety of quenched (open symbols) and slow-cooled (solid symbols) LPE samples drawn at 75 °C...

Figure 11-17. Change in the crystallinity acryst and the degree of orientation /with draw ratio a on stretching a poly(ethylene) at 60°C. The poly(ethylene) was either quenched (0) or slowly cooled (O) from the melt before drawing. (After W. Glenz and A. Peterlin.)...

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