| 摘要 |
Process comprises (a) extruding and pre-expanding a tubular foam sheet through an annular die, (b) cooling, cutting and flattening the pre-expanded extrudate, (c) subjecting the sheet, immediately after flattening, to final foaming, by passing through a heated aq. bath, or treating with steam, and (d) sheathing the foam sheet on both sides, e.g. with paper, in a conventional sheathing station. No intermediate storage of the sheet is required, prodn. being uninterrupted from extrusion to sheathing. Provision of a large storage area is unnecessary. Design provides excellent adhesion between the foam sheet and the sheathing material and gives foam sheets having a uniform cellular surface, formation of solid crusts being avoided. |
