Abstract: The process includes: A) feeding the propylene-based polymer to the first inlet and discharging the first melt composition from the first outlet, wherein the first screw is operated at a first screw speed and B) feeding the first melt composition to the second inlet and feeding the further component to the side inlet and discharging the second melt composition from the second outlet, wherein the second screw is operated at a second screw speed smaller than the first screw speed.

Abstract: A compounding extruder includes a melting section having a first cylindrical tube having a first inlet to receive a propylene polymer and a first outlet to discharge a first melt composition and a first screw arranged in the first cylindrical tube and having a first length, a first outer screw diameter Do1 and a first inner screw diameter to convey the propylene polymer and to the first outlet and a mixing section comprising a second cylindrical tube having a second inlet to receive, the first melt composition from the first outlet, an end having a second outlet and a side inlet between the second inlet and the second outlet to receive a further component, and a second screw arranged in the second cylindrical to convey the first melt composition and the further component to the second outlet, wherein Do1 is 0.82 to 1.2×Do2.

Abstract: A process for producing a polypropylene composition using a compounding extruder includes a) a melting section having a first elongated cylindrical tube with a first inlet port to receive a propylene-based polymer and additives containing an elastomer of ethylene and ?-olefin comonomer having 4 to 8 carbon atoms and a first outlet port to discharge a first melt composition containing a melt of the propylene-based polymer and the additives and a first screw arranged in the first elongated cylindrical tube, convey the propylene-based polymer and the additives to the first outlet port, and a mixing section including a second elongated cylindrical tube having a second inlet port to receive the first melt composition, and a second outlet port to discharge a second melt composition containing the first melt composition and the optional further component and a second screw arranged in the second elongated cylindrical tube to convey the first melt composition to the second outlet, wherein the first screw and the seco