| 摘要 |
1505286 Moulding isotropic foams NIHON SOFLAN CHEMICAL & ENG CO Ltd 24 Oct 1975 [12 Sept 1975] 43901/75 Heading B5A A process for forming a polyisocyanate foam having an isotropic cell structure comprises allowing the foaming composition to rise freely and to spread out in at least one direction perpendicular to the free rising direction Z. The foam may be formed in a mould provided with walls which can be opened out to allow the foam to spread, e.g. hinged metal or plywood walls 3, as shown in Figs. 8, 9, walls having folds at the corners (Fig. 15, not shown), or throughout in a bellows construction (Figs. 13, 14, not shown). During foaming the walls may be opened out by a screw- or hydraulically operated arm 12 mounted on an outer frame or container 1. The latter may be provided with rollers 2 to facilitate mould removal. The mould may comprise a base-plate 4 having a wall spacer 5 and supported on cushioning material 9. Metal fittings 8 allow the walls 3 to be separated from one another. The walls 3 may be opened out in dependence upon the foaming height and/or velocity in the free rising direction Z. A pivotable or vertically movable contact detector 11 may be employed to initiate movement of the arm(s) 12. The foam may be formed as a plate, cube, or arcuate in cross-section and may comprise a polyurethane, a polyisocyanurate, a polycarbodiimide or a mixture of two or more thereof. Paper, plastics sheets, plywood, asbestos and metal laminates may be incorporated in the foam. |
