Expanded Polystyrene is a German invented insulation material which is light weight, has good mechanical strength, low water absorption properties, and is resistant to most chemical and micro-organism attack.
Manufacturing process of insolite Expanded polystyrene. Raw EPS beads are converted into blocks and moulded parts in three stages: Pre-expansion, Intermediate ageing and moulding.
The raw material is heated with steam in foaming units to 800C – 1100C. The apparent density drops from around 630Kg/M3 (39Pcf) to around10Kg/M3 (0.625Pcf). To make packages and other types of mouldings styropore is re-expanded to 18-30Kg/M3(1.12 – 1.87 Pcf).
Prefoaming converts the compact styropor beads into foam beads with small closed cells.
As the foamed particles cool, blowing agent and steam condense insidethe cells producing a vacuum which should be equalized by air diffusing into the cells. This imparts greater mechanical stability to the beads, as well as additional foaming power. This process takes place in ventilated silos where the beads also dry.
The cavity of the foaming mould is filled pneumatically with pre-foamed material. Steam is used to soften and expand the beads which are compressed and forced against the mould wall until they fuse. The resultant block is cooled by spraying water and applying vacuum.
This technique can be used to make large blocks, boards or mouldings of almost any shape or size.