Abstract: A lay-flat device of a blown film extrusion installation includes brush rollers in the upper half entirely or partly. The brush rollers include bristles which are directed obliquely outwards and which, on contact with an extruded film tube, exert a slight spreading force on the film, by which folding is avoided.

Abstract: A single-layer or multi-layer blowing head distributes melt essentially by horizontal spiral mandrel distributors. As a result, the usual dead spaces underneath the otherwise inclined spirals are avoided, which leads to better flow conditions in the blowing head and avoids formation of specks caused by long retention times. Furthermore, the overall height is reduced by the compact arrangement of the spirals.

Abstract: A method for producing multilayer films by the blown film method includes of producing a nine-layer film by combining at least two melt streams and at most three melt streams at each of plural combining locations in a blowing head. The coextrusion blowing head includes a base plate and ten concentric rings defining nine melt channels for the nine individual melt streams. At least two of the concentric rings are supporting rings including flanged attachments for respectively receiving at least one other of the rings. The supporting rings are arranged directly on the base plate.

Abstract: A lay-flat device of a blown film extrusion installation includes brush rollers in the upper half entirely or partly. The brush rollers include bristles which are directed obliquely outwards and which, on contact with an extruded film tube, exert a slight spreading force on the film, by which folding is avoided.

Abstract: Processes and apparatus and filaments produced thereby wherein endless, molecularly oriented, multifile filaments of thermoplastic polymers are produced by extrusion of foil or web which is longitudinally ribbed to provide longitudinally extending breaking or tearing lines or zones with filament-forming ribbons or strips of polygonal cross section therebetween; cooling said foil upon exit from extrusion nozzle or immediately thereafter by air jet, cooling rollers or drums, or immersion in liquid coolant; drawing the extruded foil by at least several times its original length, e.g.