Mehrschichtige geschäumte Polyolefin-Folie, Verfahren und Vorrichtung zur deren Herstellung

摘要

The present invention relates to a process for producing a multilayer polyolefin foamed sheet, and concretely to a process and an apparatus for producing a multilayer polyolefin foamed sheet which has a smooth surface and is excellent in vacuum formability. Further, the present invention specifically relates to a multilayer polyolefin foamed sheet excellent in vacuum formability and to a foamed container body and a foamed container using the same. As a producing method of the present invention, for example, a method for producing a multilayer polyolefin foamed sheet comprising at least one polyolefin foamed layer and at least one polyolefin non-foamed layer, wherein the method uses a producing apparatus (1) comprising at least one first extruder (3) for extruding a material for forming a polyolefin foamed layer wherein the first extruder (3) is equipped with a foaming agent-supplying device for supplying a foaming agent to a cylinder, at least one second extruder (5) for extruding a material for forming a polyolefin non-foamed layer and at least one extrusion die (7) for co-extruding the material for forming a polyolefin foamed layer and the material for forming a polyolefin non-foamed layer therethrough to form the multilayer polyolefin foamed sheet, the method comprising: a melt kneading step in which, in the first extruder (3), a resin material for forming a polyolefin foamed layer is melted and the melted resin material for forming a polyolefin foamed layer and a foaming agent supplied from the foaming agent-supplying device (6) are mixed to form the material for forming a polyolefin foamed layer; a melting step in which the material for forming a polyolefin non-foamed layer is melted in the second extruder (5); and a co-extruding step in which the material for forming a polyolefin foamed layer and the material for forming a polyolefin non-foamed layer in their melted states are co-extruded into atmospheric pressure though the extrusion die (7) and the extruded material for forming a polyolefin foamed layer is foamed to form the multilayer polyolefin foamed sheet, and the like is provided.