Extruding plastics as foam core - foam being injected into sleeve inside barrel with degassing vents in core tool

摘要

Plastics are extruded as a foam core surrounded by a solid material by feeding the latter into an extruder and simultaneously introducing the foam in position, the gases from the core being vented away through the extruder, aided if necessary by adjustable vacuum. Core is homogeneous and uniformly fills the central space, product is suitable for e.g. window shutters.