A PROCESS AND APPARATUS FOR PREPARING A FOAMED ARTICLE AND A DIE THEREFOR

摘要

An improved process for preparing foamed articles of thermoplastic resin having a hard, mar-resistant surface that is flat and smooth and resembles natural wood, and an extrusion die therefor. In the process a softened thermoplastic is extruded through apertures of the extrusion die of the invention which is a fiered die having a resin discharge plate having a peripheral recessing portion and a protruding interior portion which are formed on the resin discharge plate by one or more step-ups. Each of the peripheral and interior portions of the resin discharge plate is provided with a plurality of apertures, the aperture density of the peripheral portion being greater than that of the interior portion. A longitudinally extending cooling frame is mounted adjacent the resin discharge plate and extends in the direction of extrusion to at least the forward face of the interior portion of the plate. The cooling frame together with the interior portion of the resin discharge plate form a restrictive contact zone into which foamable resin members from the recessing portion are extruded. These members are thereafter coalesced with resin members extruded from the interior portion of the plate.