MANUFACTURE OF THERMOPLASTIC RESIN FOAMED SHEET

摘要

PURPOSE:To obtain the titled sheet smooth having an even fine bubble with a high void content by extrusion foaming by cooling and molding a thermoplastic resin foamed body smooth with a roll immediately as extruded from a cap lip of an extruder being foamed. CONSTITUTION:For example, a thermoplastic resin (preferably polypropylene homopolymer or the like) is extruded in a sheet being foamed from the tip 7 through a cap lip 2 (preferably, formed by sticking out the tip 7 in the extrusion direction) mounted on an extruder while a sheet-shaped foam body 4 is cooled with a cooling roll 3 immediately to be formed smooth whereby an intended sheet is obtained. The distance 11 between the center 10 of the cooling roll 3 with the radius R and the tip 7 of the lip is preferably less than (R<2>+ 16)<1/2>mm. and the tip 7 of the lip may be almost brought into contact with a sheet contact line 8 of the roll.