Blow molding process for production of hollow type articles

摘要

A blow molding process of producing molded articles including the steps of extruding a parison of the plasticized material from a die into a gap between mold halves while the mold is open and blowing gas into the parison, while the mold is closed, to have the parison form a molded hollow article within the mold. The parison is heated before molding by heating the inner shell contoured parts of the mold at the surfaces thereof and the plasticized material at the outer surface by using an instantaneous radiation heater disposed in the mold half gap to partially encompass the parison while the mold is open and the inner shell contoured part is heated by a heating medium passed through the heat medium passages. The molded article is cooled by cooling the mold at the inner shell contoured parts thereof by flowing a cooling medium through the heat medium passages of the mold while the mold is closed. The cooling of the mold occurs alternately with the heating of the mold by the heating medium.