초록 ▼

In a process for producing a hollow body with a wall which partially comprises foamed thermoplastic material by an extrusion blow molding procedure, a preform which comprises at least first and second layers of which at least one comprises foamable plastics material is first extruded, the layer of f

In a process for producing a hollow body with a wall which partially comprises foamed thermoplastic material by an extrusion blow molding procedure, a preform which comprises at least first and second layers of which at least one comprises foamable plastics material is first extruded, the layer of foamable material is foamed, and then the preform is expanded in a blow molding mold by the application of an internal pressure. The hollow body may have a welded seam at a region of the hollow body at which an operation of squeezing off excess material has been carried out, the seam being in the form of an outwardly projecting flange web portion and the thickness thereof being such that the layer of foamable material is compressed at least to such an extent that it is not thicker than in the unfoamed condition.

대표청구항 ▼

A hollow body of thermoplastic material produced by a co-extrusion blow molding process and comprising a wall provided by a plurality of layers of which at least one layer is at least partially foamed, wherein the hollow body which is produced from a co-extrusion preform has a welded seam for closin

A hollow body of thermoplastic material produced by a co-extrusion blow molding process and comprising a wall provided by a plurality of layers of which at least one layer is at least partially foamed, wherein the hollow body which is produced from a co-extrusion preform has a welded seam for closing the hollow body at regions thereof at which excess material has been squeezed off the preform when the mold was closed, wherein said welded seam at least over part of the extent thereof is in the form of a flange portion which projects outwardly relative to the adjacent wall regions of the hollow body, and wherein the flange portion is of a thickness perpendicularly to its longitudinal extent, which is less than double the wall thickness of the preform in the foamed condition of said at least one layer of foamable material.