| 摘要 |
PURPOSE: To improve film characteristics by stably guiding a neck-shaped parison with the help of a conical drag mandrel whose height can be adjusted immediately before expansion and applying a highly intensive internal cooling action to an expandable transfer area right after the guidance. CONSTITUTION: Polyethylene pellets are loaded into a hopper 43, then are plasticized by an extruder 2 and are caused to pass through a breaker plate 35 and a die 1 under high pressure to be molded into a neck-shaped parison 44. The neck-shaped parison 44 is expanded into a tubular film 15 passing through a transfer area 45 after the parison 44 is long enough to be about 4-10 times the diameter of a nozzle. However, the neck-shaped parison 44 is guided by the conical contact face 47 of a drag mandrel 9, so that the neck-shaped parison 44 and the tubular film 15 are stabilized. And a cool air for cooling the interior passes through a space between both coaxial pipes 24, 23 inside a die 1 and also a space between an outer pipe 7 and an inner pipe 8 outside the die 1, and then is supplied to inner nozzle lips 10, 11, 12, 13 via the conical drag mandrel 9. Consequently, it is possible to obtain superb physical and mechanical film characteristics. |
