A mixer structure for a film die for a polymer melt includes multiple web elements. The web elements include a first web element and a second web element. The first web element and the second web element include at least an end, which is connected to a base. A film die includes a first tool element, a second tool element, and a flow channel for the polymer melt extending between the first tool element and the second tool element. The mixer structure is arranged in the flow channel. The mixer structure is held in at least one of the tool elements by a holding element.

Techniques recycle plastics in multiple successive process steps. A polymer, preferably a recyclable material, is melted using a discharge extruder, filtered using a first filter device under a positive pressure atmosphere, filtered and degassed using a degassing device, and discharged using a discharge extruder. The degassing device has at least one filter element and a vacuum chamber with a negative pressure atmosphere for filtering and degassing purposes, wherein the plastic melt can be conducted into the negative pressure atmosphere of the vacuum chamber through the filter element.

An extruder includes a mixing device having a mixing chamber formed by a housing, a stator and a rotor. The stator and the rotor are arranged at least partially within the mixing chamber. The stator is connected to the housing and/or is formed by the housing. The rotor is rotatable about an axis of rotation (D). At least one free space, into which the stator projects at least partially in the direction of the axis of rotation (D), is formed by the rotor. The stator and/or the rotor have/has at least one temperature control channel, through which a temperature control fluid can be made to flow in order to control the temperature of the stator and/or of the rotor. The extruder further includes a screw housing, a screw drive, and an extruder screw, which is mounted to the screw housing and is coupled to the screw drive.

Rheology-modified, additive-containing ethylenic polymer compositions are prepared in a continuously operated extruder comprising first, second and third zones by a process comprising the steps of: mixing in the second zone of the extruder an ethylenic polymer and a high-temperature decomposing peroxide at a temperature such that the half-life of the peroxide is equal to or greater than one minute and for a sufficient period of time to modify the rheology of the ethylenic polymer to produce a rheology-modified, melted ethylenic polymer for transfer to the third zone of the extruder; and adding to the third zone one or more additives to the rheology-modified, melted ethylenic polymer to produce the rheology-modified, additive-containing ethylenic polymer.