The present invention relates to an extruder for a polymer, and a process for extruding a polymer using said extruder. In particular, the present invention provides an extruder comprising: (i) two or more barrel sections arranged sequentially from: (a) an upstream feed barrel section to which polymer feedstock to be extruded is fed, the upstream feed barrel section containing two or more screws each having a diameter of X; to (b) a downstream barrel section from which melted polymer is passed to a die and extruded; and (ii) one or more feed ports for feeding polymer feedstock to be extruded into the extruder at its upstream end, characterised in that the total area of the one or more feed ports through which polymer feedstock is introduced is greater than 4*X2, and a process for extrusion of polymer comprising feeding a polymer feedstock to the feed port of such an extruder.