| 摘要 |
A porcess for producing a foamed synthetic resin body comprising continuously extruding a foamable thermoplastic resin extrudate composition from an extruder die (2, 3) into a reduced pressure zone (11, 19), subjecting the extrudate (F) to en expansion molding step, a cooling-hardening step and a cutting step while transporting the extrudate through the reduced pressure zone to obtain a foamed piece of predetermined length (F min ), shutting off a portion (19) of the reduced pressure zone surrounding the foamed piece from the other portion thereof when the foamed piece has reached a specified position to restore the foamed piece surrounding portion to a normal pressure, subsequently discharging the foamed piece into the atmosphere, and thereafter bringing the surrounding portion into communication with the reduced pressure zone again upon reducing the pressure. Foamed resin bodies of desired expansion ratio and shape can be prepared continuously with high cooling efficiency. An apparatus for practicing the process is also disclosed. Such apparatus includes means to form a continuous length of extrudate with a vacuum chamber and means to cut the extrudate to length and means to pass (10, 10 min ) the cut extrudate into a second chamber (19), and then to cause the cut length to exit the second chamber (11) without affecting the reduced pressure in the chamber or reduced pressure zone. |
