Apparatus and methods for molding expanded synthetic resin

摘要

A mold apparatus for producing a synthetic resin foam part has a mold assembly (1) comprising a lower mold (2), an upper mold (3) removably attached to the lower mold to define a closed space, and an insert (4) removably disposed in the closed space. The insert has a partition (6) which is faced to the upper mold through a gap (11). The partition defines a chamber (7) between the insert and the upper mold. The closed space excluding the chamber constitutes a cavity (8) into which a molding compound is introduced. A pressure regulator means (21) is provided for exhausting air from the chamber (7) to keep the chamber in a subatmospheric pressure whereby air in the cavity (8) is also exhausted through the gap. A foam part is produced by feeding a synthetic resin blow molding compound into the cavity (8) under atmospheric pressure, tightly closing the mold assembly, exhausting air from the chamber and from the cavity through the gap to establish a subatmospheric pressure in the cavity, and causing the molding compound to be blow molded.