Prodn of foam sheeting by feeding polyurethane liquid onto conveyor - and applying pressers against foam in region of expansion

摘要

Liq. polyurethane contg. a foaming agent is extruded onto a conveyor provided with side walls the conveyor and side walls being covered with a lining matl. and a facing sheet being applied to the upper surface of the foam. Presser elements (e.g. rollers, plates) are mounted on pivotal arms and are applied against the upper surface of foam in the region of expansion to control the expansion, the arms being adjustable to control the force applied by the presser elements to the foam. A device, pref. a heater is provided to bond the facin sheet to the foam and the lining when the foam is fully expanded, and a perforator, e.g. a needled roll is provided to perforate the facing sheet to allow escape of gases produced during expansion. The central region of the foam, which is hotter, is prevented by the presser elements from expanding by a greater amt., to ensure a flat smooth upper surface on the final foam sheet.