Blown Film Apparatus

We seek to produce a multilayered film of two polymers from a coextrusion blown film apparatus. The die is of the annular type with the mandrel rotating (see Fig. 6.31a) and its dimensions are kR = 4.8 cm, R = 5.0 cm, and L = 15 cm. The two polymers, which are presented in the schematic by black and white colors, have the same Newtonian viscosity, fj, = 500 Pa-s, at the extrusion temperature. The pressure drop in the die is AP = 3.45 MPa (500 psi) and the total volumetric flow rate is Q = 9.43 cm /s. The feedport system consists of 20 equal-size ports in total, 10 for the first polymer (black) and the other 10 for the second polymer (white). A similar feedport system with 16 ports in total is shown in... 

Figure 7.4 Tubular film apparatus (a) extruder (b) rotating blown film die (c) haul-off unit (d) pretreatment unit (e) wind-up unit (f) edge trimmer (g) longitudinal cutter (h) transverse cutter...

The die is a circular apparatus with a slit around the circumference of the die where the molten polyethylene exits the extruder to begin the blown-film-forming step. 

Dow Chemical claims a patent on a blend [11] with a decreased tendency toward delamination, which exhibits a desirable balance of properties, a high level of impact resistance, solvent resistance, and processability. The product can be blown into films, spun into fibers, extruded into sheets, formed into multilayer laminates, and molded into any desired shape and can be used in data storage apparatus, appliance and instrument housings, motor vehicle body panels, and other parts and components for use in electrical, automotive, and electronic industries. 

---