In-mold foaming of polyolefin components includes interrupting cooling at a certain pressure, removing from mold and hardening in a support

摘要

Polyolefin components are made by filling (23) a mold space (4) with pre-foamed pellets, heating with steam (30a) and cooling. During cooling the pressure is measured and at a predetermined pressure, e.g. between 0.02 and 0.2 Mpa, cooling is stopped. The component is removed from the mold and hardening completed, e.g. for 5 to 60 minutes, while the component is held in a support. Cooling is carried out largely by external water sprays (20) and the mold walls are not perforated by access holes for air or water.