Planetary roller extruder with a degassing section

An extruder for producing and processing polymer-based adhesives and polymer mixture-based adhesives, including a planetary roller degassing section comprising:

• a housing;
• a bushing arranged within the housing, the bushing having an internal toothing with a pitch diameter and a root circle;
• an externally toothed central spindle arranged within the housing;
• planetary spindles, configured and disposed to rotate about the central spindle between the central spindle and the bushing while intermeshing with the toothing of the central spindle and the toothing of the bushing;
• a heat transfer fluid which is guided through fluid channels which extend helically along an outer surface of the bushing and guide the heat transfer fluid axially;
• and
• a degassing opening to which a negative pressure is applied for degassing, wherein:
• a minimum radial thickness (t) of the bushing between the root circle of the internal toothing on an inside of the bushing and a bottom of the fluid channels on an outside of the bushing is selected based on the pitch diameter (d) of the internal toothing according to the following table:
• minimum material
• pitch diameter (d)
• thickness (t)
• d ≤ 85 mm
• t ≤ 4.5 mm
• 85 mm < d ≤ 125 mm
• t ≤ 4.5 mm
• 125 mm < d ≤ 165 mm
• t ≤ 5.0 mm
• 165 mm < d ≤ 190 mm
• t ≤ 5.7 mm
• 190 mm < d ≤ 225 mm
• t ≤ 5.6 mm
• 225 mm < d ≤ 265 mm
• t ≤ 5.7 mm
• 265 mm < d ≤ 290 mm
• t ≤ 6.0 mm
• 290 mm < d ≤ 350 mm
• t ≤ 6.0 mm
• d > 350 mm
• t ≤ 6.5 mm
• the extruder comprises fewer planetary spindles than a maximum number of planetary spindles that could be accommodated between the central spindle and the bushing;
• and
• gas is extracted from a cavity formed at an inlet side of the extruder,
• whereby the minimum radial thickness of the bushing provides a wall thickness that increases heat transfer between
• the polymer-based adhesives or polymer mixture-based adhesives and
• the heat transfer fluid in the fluid channels to avoid deterioration of the polymer-based adhesives or polymer mixture-based adhesives during the processing.